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Hinton A, Katti P, Mungai M, Hall DD, Koval O, Shao J, Vue Z, Lopez EG, Rostami R, Neikirk K, Ponce J, Streeter J, Schickling B, Bacevac S, Grueter C, Marshall A, Beasley HK, Do Koo Y, Bodine SC, Nava NGR, Quintana AM, Song LS, Grumbach IM, Pereira RO, Glancy B, Abel ED. ATF4-dependent increase in mitochondrial-endoplasmic reticulum tethering following OPA1 deletion in skeletal muscle. J Cell Physiol 2024; 239:e31204. [PMID: 38419397 DOI: 10.1002/jcp.31204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 12/15/2023] [Accepted: 01/16/2024] [Indexed: 03/02/2024]
Abstract
Mitochondria and endoplasmic reticulum (ER) contact sites (MERCs) are protein- and lipid-enriched hubs that mediate interorganellar communication by contributing to the dynamic transfer of Ca2+, lipid, and other metabolites between these organelles. Defective MERCs are associated with cellular oxidative stress, neurodegenerative disease, and cardiac and skeletal muscle pathology via mechanisms that are poorly understood. We previously demonstrated that skeletal muscle-specific knockdown (KD) of the mitochondrial fusion mediator optic atrophy 1 (OPA1) induced ER stress and correlated with an induction of Mitofusin-2, a known MERC protein. In the present study, we tested the hypothesis that Opa1 downregulation in skeletal muscle cells alters MERC formation by evaluating multiple myocyte systems, including from mice and Drosophila, and in primary myotubes. Our results revealed that OPA1 deficiency induced tighter and more frequent MERCs in concert with a greater abundance of MERC proteins involved in calcium exchange. Additionally, loss of OPA1 increased the expression of activating transcription factor 4 (ATF4), an integrated stress response (ISR) pathway effector. Reducing Atf4 expression prevented the OPA1-loss-induced tightening of MERC structures. OPA1 reduction was associated with decreased mitochondrial and sarcoplasmic reticulum, a specialized form of ER, calcium, which was reversed following ATF4 repression. These data suggest that mitochondrial stress, induced by OPA1 deficiency, regulates skeletal muscle MERC formation in an ATF4-dependent manner.
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Affiliation(s)
- Antentor Hinton
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Fraternal Order of Eagles Diabetes Research Center, Iowa City, Iowa, USA
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Prasanna Katti
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Margaret Mungai
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Fraternal Order of Eagles Diabetes Research Center, Iowa City, Iowa, USA
| | - Duane D Hall
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Olha Koval
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Fraternal Order of Eagles Diabetes Research Center, Iowa City, Iowa, USA
| | - Jianqiang Shao
- Central Microscopy Research Facility, Iowa City, Iowa, USA
| | - Zer Vue
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Edgar Garza Lopez
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Rahmati Rostami
- Department of Genetic Medicine, Joan & Sanford I. Weill Medical College of Cornell University, New York, New York, USA
| | - Kit Neikirk
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Jessica Ponce
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Fraternal Order of Eagles Diabetes Research Center, Iowa City, Iowa, USA
| | - Jennifer Streeter
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Fraternal Order of Eagles Diabetes Research Center, Iowa City, Iowa, USA
| | - Brandon Schickling
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Department of Medicine, Duke University, Durham, North Carolina, USA
| | - Serif Bacevac
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Fraternal Order of Eagles Diabetes Research Center, Iowa City, Iowa, USA
| | - Chad Grueter
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Fraternal Order of Eagles Diabetes Research Center, Iowa City, Iowa, USA
| | - Andrea Marshall
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Heather K Beasley
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Young Do Koo
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Fraternal Order of Eagles Diabetes Research Center, Iowa City, Iowa, USA
| | - Sue C Bodine
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Fraternal Order of Eagles Diabetes Research Center, Iowa City, Iowa, USA
- Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Nayeli G Reyes Nava
- Department of Biological Sciences, Border Biomedical Research Center, The University of Texas at El Paso, El Paso, Texas, USA
| | - Anita M Quintana
- Department of Biological Sciences, Border Biomedical Research Center, The University of Texas at El Paso, El Paso, Texas, USA
| | - Long-Sheng Song
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Fraternal Order of Eagles Diabetes Research Center, Iowa City, Iowa, USA
| | - Isabella M Grumbach
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Fraternal Order of Eagles Diabetes Research Center, Iowa City, Iowa, USA
| | - Renata O Pereira
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Fraternal Order of Eagles Diabetes Research Center, Iowa City, Iowa, USA
| | - Brian Glancy
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - E Dale Abel
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Fraternal Order of Eagles Diabetes Research Center, Iowa City, Iowa, USA
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
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Lu HJ, Koju N, Sheng R. Mammalian integrated stress responses in stressed organelles and their functions. Acta Pharmacol Sin 2024:10.1038/s41401-023-01225-0. [PMID: 38267546 DOI: 10.1038/s41401-023-01225-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 12/30/2023] [Indexed: 01/26/2024] Open
Abstract
The integrated stress response (ISR) triggered in response to various cellular stress enables mammalian cells to effectively cope with diverse stressful conditions while maintaining their normal functions. Four kinases (PERK, PKR, GCN2, and HRI) of ISR regulate ISR signaling and intracellular protein translation via mediating the phosphorylation of eukaryotic translation initiation factor 2 α (eIF2α) at Ser51. Early ISR creates an opportunity for cells to repair themselves and restore homeostasis. This effect, however, is reversed in the late stages of ISR. Currently, some studies have shown the non-negligible impact of ISR on diseases such as ischemic diseases, cognitive impairment, metabolic syndrome, cancer, vanishing white matter, etc. Hence, artificial regulation of ISR and its signaling with ISR modulators becomes a promising therapeutic strategy for relieving disease symptoms and improving clinical outcomes. Here, we provide an overview of the essential mechanisms of ISR and describe the ISR-related pathways in organelles including mitochondria, endoplasmic reticulum, Golgi apparatus, and lysosomes. Meanwhile, the regulatory effects of ISR modulators and their potential application in various diseases are also enumerated.
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Affiliation(s)
- Hao-Jun Lu
- Department of Pharmacology and Laboratory of Aging and Nervous Diseases, Jiangsu Key Laboratory of Neuropsychiatric Diseases, College of Pharmaceutical Sciences of Soochow University, Suzhou, 215123, China
| | - Nirmala Koju
- Department of Pharmacology and Laboratory of Aging and Nervous Diseases, Jiangsu Key Laboratory of Neuropsychiatric Diseases, College of Pharmaceutical Sciences of Soochow University, Suzhou, 215123, China
| | - Rui Sheng
- Department of Pharmacology and Laboratory of Aging and Nervous Diseases, Jiangsu Key Laboratory of Neuropsychiatric Diseases, College of Pharmaceutical Sciences of Soochow University, Suzhou, 215123, China.
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Li R, Yang L, Li S, Chen S, Ren Y, Shen L, Dong L, Chen X, Li J, Xu M. C/EBPα alleviates hepatic ischemia-reperfusion injury by inhibiting endoplasmic reticulum stress via HDAC1-mediated deacetylation of ATF4. J Biochem Mol Toxicol 2024; 38:e23630. [PMID: 38229308 DOI: 10.1002/jbt.23630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 12/01/2023] [Accepted: 12/14/2023] [Indexed: 01/18/2024]
Abstract
Hepatic ischemia-reperfusion (IR) injury is a complex systemic process causing a series clinical problem. C/EBPα is a key transcription factor for hepatocyte function, but its role and mechanism in regulating hepatic IR injury are largely unknown. Occluding portal vein and hepatic artery was used to establish a mouse model of hepatic IR injury. C/EBPα expression was decreased in IR-injured liver compared with the sham, accompanied by increased contents of serum alanine transaminase (ALT), aspartate transaminase (AST), high mobility group box-1, and proportion of hepatic cells. Oxygen and glucose deprivation/recovery (OGD/R) was used to establish a cellular hepatic IR model in WRL-68 hepatocytes in vitro, and C/EBPα was overexpressed in the hepatocytes to evaluate its effect on hepatic IR injury. OGD/R promoted oxidative stress, cell apoptosis and endoplasmic reticulum (ER) stress in hepatocytes, which was reversed by C/EBPα overexpression. Then, we found that C/EBPα promoted histone deacetylase 1 (HDAC1) transcription through binding to HDAC1 promoter. Moreover, HDAC1 deacetylated the activating transcription factor 4 (ATF4), a key positive regulator of ER stress. Trichostatin-A (an HDAC inhibitor) or ATF4 overexpression reversed the improvement of C/EBPα on OGD/R-induced ER stress and hepatocyte dysfunction. 4-Phenylbutyric acid (an endoplasmic reticulum stress inhibitor) also reversed the hepatic IR injury induced by ATF4 overexpression. Finally, lentivirus-mediated C/EBPα overexpression vector was applied to administrate hepatic IR mice, and the results showed that C/EBPα overexpression ameliorated IR-induced hepatic injury, manifesting with reduced ALT/AST, oxidative stress and ER stress. Altogether, our findings suggested that C/EBPα ameliorated hepatic IR injury by inhibiting ER stress via HDAC1-mediated deacetylation of ATF4 promoter.
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Affiliation(s)
- Rong Li
- Department of Anesthesiology, The Second Affiliated Hospital of Xi'an JiaoTong University, Xi'an, People's Republic of China
| | - Longbao Yang
- Department of Gastroenterology, The Second Affiliated Hospital of Xi'an JiaoTong University, Xi'an, People's Republic of China
| | - Shunle Li
- Department of General Surgery, The Second Affiliated Hospital of Xi'an JiaoTong University, Xi'an, People's Republic of China
| | - Shuo Chen
- Department of General Surgery, The Second Affiliated Hospital of Xi'an JiaoTong University, Xi'an, People's Republic of China
| | - Yifan Ren
- Department of General Surgery, The Second Affiliated Hospital of Xi'an JiaoTong University, Xi'an, People's Republic of China
| | - Lin Shen
- Department of Gastroenterology, The Second Affiliated Hospital of Xi'an JiaoTong University, Xi'an, People's Republic of China
| | - Lei Dong
- Department of Gastroenterology, The Second Affiliated Hospital of Xi'an JiaoTong University, Xi'an, People's Republic of China
| | - Xi Chen
- Department of General Surgery, The Second Affiliated Hospital of Xi'an JiaoTong University, Xi'an, People's Republic of China
| | - Junhui Li
- Department of General Surgery, The Second Affiliated Hospital of Xi'an JiaoTong University, Xi'an, People's Republic of China
| | - Meng Xu
- Department of General Surgery, The Second Affiliated Hospital of Xi'an JiaoTong University, Xi'an, People's Republic of China
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Jiao Y, Peng X, Wang Y, Hao Z, Chen L, Wu M, Zhang Y, Li J, Li W, Zhan X. Malignant ascites supernatant enhances the proliferation of gastric cancer cells partially via the upregulation of asparagine synthetase. Oncol Lett 2023; 26:418. [PMID: 37664666 PMCID: PMC10472050 DOI: 10.3892/ol.2023.14005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 06/09/2023] [Indexed: 09/05/2023] Open
Abstract
Malignant ascites (MA) is a common manifestation of advanced gastric cancer (GC) with peritoneal metastasis (PM), which usually indicates a poor prognosis. The present study aimed to explore the effects of MA, a unique microenvironment of PM, on the proliferation of cancer cells and investigate the underlying mechanisms. Ex vivo experiments demonstrated that GC cells treated with MA exhibited enhanced proliferation. RNA sequencing indicated that asparagine synthetase (ASNS) was one of the differentially expressed genes in GC cells following incubation with MAs. Furthermore, the present study suggested that MA induced an upregulation of ASNS expression and the stimulatory effect of MA on cancer cell proliferation was alleviated upon ASNS downregulation. Activating transcription factor 4 (ATF4), a pivotal transcription factor regulating ASNS, was upregulated when cells were treated with MA supernatant. After ATF4 knockdown, the proliferation of MA-treated GC cells and the expression of ASNS decreased. In addition, the decline in the proliferation of the ATF4-downregulated AGS GC cell line was rescued by ASNS upregulation. The findings indicated that MA could promote the proliferation of GC cells via activation of the ATF4-ASNS axis. Hence, it may be a potential target for treating GC with PM and MA.
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Affiliation(s)
- Yuan Jiao
- Department of Oncology, Changhai Hospital, Naval Medical University, Shanghai 200433, P.R. China
| | - Xiaobo Peng
- Department of Oncology, Changhai Hospital, Naval Medical University, Shanghai 200433, P.R. China
| | - Yujie Wang
- Department of Oncology, Changhai Hospital, Naval Medical University, Shanghai 200433, P.R. China
| | - Zhibin Hao
- Department of Oncology, Changhai Hospital, Naval Medical University, Shanghai 200433, P.R. China
| | - Ling Chen
- Department of Oncology, Changhai Hospital, Naval Medical University, Shanghai 200433, P.R. China
| | - Meihong Wu
- Department of Oncology, Changhai Hospital, Naval Medical University, Shanghai 200433, P.R. China
| | - Yingyi Zhang
- Department of Oncology, Changhai Hospital, Naval Medical University, Shanghai 200433, P.R. China
| | - Jie Li
- Department of Oncology, Changhai Hospital, Naval Medical University, Shanghai 200433, P.R. China
| | - Wenlin Li
- Department of Cell Biology, Naval Medical University, Shanghai 200433, P.R. China
| | - Xianbao Zhan
- Department of Oncology, Changhai Hospital, Naval Medical University, Shanghai 200433, P.R. China
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Kumar A, Karuppagounder SS, Chen Y, Corona C, Kawaguchi R, Cheng Y, Balkaya M, Sagdullaev BT, Wen Z, Stuart C, Cho S, Ming GL, Tuvikene J, Timmusk T, Geschwind DH, Ratan RR. 2-Deoxyglucose drives plasticity via an adaptive ER stress-ATF4 pathway and elicits stroke recovery and Alzheimer's resilience. Neuron 2023; 111:2831-2846.e10. [PMID: 37453419 PMCID: PMC10528360 DOI: 10.1016/j.neuron.2023.06.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 05/10/2023] [Accepted: 06/20/2023] [Indexed: 07/18/2023]
Abstract
Intermittent fasting (IF) is a diet with salutary effects on cognitive aging, Alzheimer's disease (AD), and stroke. IF restricts a number of nutrient components, including glucose. 2-deoxyglucose (2-DG), a glucose analog, can be used to mimic glucose restriction. 2-DG induced transcription of the pro-plasticity factor, Bdnf, in the brain without ketosis. Accordingly, 2-DG enhanced memory in an AD model (5xFAD) and functional recovery in an ischemic stroke model. 2-DG increased Bdnf transcription via reduced N-linked glycosylation, consequent ER stress, and activity of ATF4 at an enhancer of the Bdnf gene, as well as other regulatory regions of plasticity/regeneration (e.g., Creb5, Cdc42bpa, Ppp3cc, and Atf3) genes. These findings demonstrate an unrecognized role for N-linked glycosylation as an adaptive sensor to reduced glucose availability. They further demonstrate that ER stress induced by 2-DG can, in the absence of ketosis, lead to the transcription of genes involved in plasticity and cognitive resilience as well as proteostasis.
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Affiliation(s)
- Amit Kumar
- Burke Neurological Institute and Brain and Mind Research Institute, Weill Cornell Medicine, 785 Mamaroneck Ave, White Plains, NY, USA
| | - Saravanan S Karuppagounder
- Burke Neurological Institute and Brain and Mind Research Institute, Weill Cornell Medicine, 785 Mamaroneck Ave, White Plains, NY, USA
| | - Yingxin Chen
- Burke Neurological Institute and Brain and Mind Research Institute, Weill Cornell Medicine, 785 Mamaroneck Ave, White Plains, NY, USA
| | - Carlo Corona
- Burke Neurological Institute and Brain and Mind Research Institute, Weill Cornell Medicine, 785 Mamaroneck Ave, White Plains, NY, USA
| | - Riki Kawaguchi
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Yuyan Cheng
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Mustafa Balkaya
- Burke Neurological Institute and Brain and Mind Research Institute, Weill Cornell Medicine, 785 Mamaroneck Ave, White Plains, NY, USA
| | - Botir T Sagdullaev
- Burke Neurological Institute and Brain and Mind Research Institute, Weill Cornell Medicine, 785 Mamaroneck Ave, White Plains, NY, USA; Regeneron Pharmaceuticals, Tarrytown, New York, NY, USA
| | - Zhexing Wen
- Departments of Psychiatry and Behavioral Sciences, Cell Biology, and Neurology, Emory University School of Medicine, Atlanta, GA, USA
| | - Charles Stuart
- East Tennessee State University Quillen College of Medicine, Johnson City, TN, USA
| | - Sunghee Cho
- Burke Neurological Institute and Brain and Mind Research Institute, Weill Cornell Medicine, 785 Mamaroneck Ave, White Plains, NY, USA
| | - Guo-Li Ming
- Department of Neuroscience, Perelman School for Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jürgen Tuvikene
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
| | - Tõnis Timmusk
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
| | - Daniel H Geschwind
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Rajiv R Ratan
- Burke Neurological Institute and Brain and Mind Research Institute, Weill Cornell Medicine, 785 Mamaroneck Ave, White Plains, NY, USA.
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Nagao Y, Amo-Shiinoki K, Nakabayashi H, Hatanaka M, Kondo M, Matsunaga K, Emoto M, Okuya S, Tanizawa Y, Tanabe K. Gsk-3-Mediated Proteasomal Degradation of ATF4 Is a Proapoptotic Mechanism in Mouse Pancreatic β-Cells. Int J Mol Sci 2022; 23:13586. [PMID: 36362372 PMCID: PMC9657557 DOI: 10.3390/ijms232113586] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 10/30/2022] [Accepted: 11/02/2022] [Indexed: 03/14/2024] Open
Abstract
Endoplasmic reticulum (ER) stress is a key pathogenic factor in type 1 and 2 diabetes. Glycogen synthase kinase 3 (Gsk-3) contributes to β-cell loss in mice. However, the mechanism by which Gsk-3 leads β-cell death remains unclear. ER stress was pharmacologically induced in mouse primary islets and insulinoma cells. We used insulinoma cells derived from Akita mice as a model of genetic ER stress. Gsk-3 activity was blocked by treating with Gsk-3 inhibitors or by introducing catalytically inactive Gsk-3β. Gsk-3 inhibition prevented proteasomal degradation of activating transcriptional factor 4 (ATF4) and alleviated apoptosis. We found that ATF4-S214 was phosphorylated by Gsk-3, and that this was required for a binding of ATF4 with βTrCP, which mediates polyubiquitination. The anti-apoptotic effect of Gsk-3 inhibition was attenuated by introducing DN-ATF4 or by knockdown of ATF4. Mechanistically, Gsk-3 inhibition modulated transcription targets of ATF4 and in turn facilitated dephosphorylation of eIF2α, altering the protein translational dynamism under ER stress. These observations were reproduced in the Akita mouse-derived cells. Thus, these results reveal the role of Gsk-3 in the regulation of the integrated stress response, and provide a rationale for inhibiting this enzyme to prevent β-cell death under ER stress conditions.
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Affiliation(s)
- Yuko Nagao
- Division of Endocrinology, Metabolism, Haematological Sciences and Therapeutics, Graduate School of Medicine, Yamaguchi University, Ube 755-8505, Japan
| | - Kikuko Amo-Shiinoki
- Division of Endocrinology, Metabolism, Haematological Sciences and Therapeutics, Graduate School of Medicine, Yamaguchi University, Ube 755-8505, Japan
- Department of Diabetes Research, School of Medicine, Yamaguchi University, Ube 755-8505, Japan
| | - Hiroko Nakabayashi
- Division of Endocrinology, Metabolism, Haematological Sciences and Therapeutics, Graduate School of Medicine, Yamaguchi University, Ube 755-8505, Japan
| | - Masayuki Hatanaka
- Division of Endocrinology, Metabolism, Haematological Sciences and Therapeutics, Graduate School of Medicine, Yamaguchi University, Ube 755-8505, Japan
| | - Manabu Kondo
- Division of Endocrinology, Metabolism, Haematological Sciences and Therapeutics, Graduate School of Medicine, Yamaguchi University, Ube 755-8505, Japan
| | - Kimie Matsunaga
- Division of Endocrinology, Metabolism, Haematological Sciences and Therapeutics, Graduate School of Medicine, Yamaguchi University, Ube 755-8505, Japan
| | - Masahiro Emoto
- Division of Endocrinology, Metabolism, Haematological Sciences and Therapeutics, Graduate School of Medicine, Yamaguchi University, Ube 755-8505, Japan
| | - Shigeru Okuya
- Health Administration Centre, Organisation for University Education, Yamaguchi University, Yamaguchi 753-8511, Japan
| | - Yukio Tanizawa
- Division of Endocrinology, Metabolism, Haematological Sciences and Therapeutics, Graduate School of Medicine, Yamaguchi University, Ube 755-8505, Japan
| | - Katsuya Tanabe
- Division of Endocrinology, Metabolism, Haematological Sciences and Therapeutics, Graduate School of Medicine, Yamaguchi University, Ube 755-8505, Japan
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Wen Z, Xiong X, Chen D, Shao L, Tang X, Shen X, Zhang S, Huang S, Zhang L, Chen Y, Zhang Y, Wang C, Liu J. Activating transcription factor 4 protects mice against sepsis-induced intestinal injury by regulating gut-resident macrophages differentiation. Chin Med J (Engl) 2022; 135:2585-2595. [PMID: 36469355 PMCID: PMC9945183 DOI: 10.1097/cm9.0000000000002543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Gut-resident macrophages (gMacs) supplemented by monocytes-to-gMacs differentiation play a critical role in maintaining intestinal homeostasis. Activating transcription factor 4 (ATF4) is involved in immune cell differentiation. We therefore set out to investigate the role of ATF4-regulated monocytes-to-gMacs differentiation in sepsis-induced intestinal injury. METHODS Sepsis was induced in C57BL/6 wild type (WT) mice and Atf4- knockdown ( Atf4+/ - ) mice by cecal ligation and puncture or administration of lipopolysaccharide (LPS). Colon, peripheral blood mononuclear cells, sera, lung, liver, and mesenteric lymph nodes were collected for flow cytometry, hematoxylin and eosin staining, immunohistochemistry, quantitative reverse transcription polymerase chain reaction, and enzyme-linked immunosorbent assay, respectively. RESULTS CD64, CD11b, Ly6C, major histocompatibility complex-II (MHC-II), CX3CR1, Ly6G, and SSC were identified as optimal primary markers for detecting the process of monocytes-to-gMacs differentiation in the colon of WT mice. Monocytes-to-gMacs differentiation was impaired in the colon during sepsis and was associated with decreased expression of ATF4 in P1 (Ly6C hi monocytes), the precursor cells of gMacs. Atf4 knockdown exacerbated the impairment of monocytes-to-gMacs differentiation in response to LPS, resulting in a significant reduction of gMacs in the colon. Furthermore, compared with WT mice, Atf4+/- mice exhibited higher pathology scores, increased expression of inflammatory factor genes ( TNF-α, IL-1β ), suppressed expression of CD31 and vascular endothelial-cadherin in the colon, and increased translocation of intestinal bacteria to lymph nodes and lungs following exposure to LPS. However, the aggravation of sepsis-induced intestinal injury resulting from Atf4 knockdown was not caused by the enhanced inflammatory effect of Ly6C hi monocytes and gMacs. CONCLUSION ATF4, as a novel regulator of monocytes-to-gMacs differentiation, plays a critical role in protecting mice against sepsis-induced intestinal injury, suggesting that ATF4 might be a potential therapeutic target for sepsis treatment.
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Affiliation(s)
- Zhenliang Wen
- Department of Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Xi Xiong
- Department of Critical Care Medicine, Shanghai Children's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200062, China
- Institute of Pediatric Infection, Immunity, and Critical Care Medicine, Shanghai Children's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200062, China
| | - Dechang Chen
- Department of Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Lujing Shao
- Department of Critical Care Medicine, Shanghai Children's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200062, China
- Institute of Pediatric Infection, Immunity, and Critical Care Medicine, Shanghai Children's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200062, China
| | - Xiaomeng Tang
- Department of Critical Care Medicine, Shanghai Children's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200062, China
- Institute of Pediatric Infection, Immunity, and Critical Care Medicine, Shanghai Children's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200062, China
| | - Xuan Shen
- Department of Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Sheng Zhang
- Department of Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Sisi Huang
- Department of Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Lidi Zhang
- Department of Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Yizhu Chen
- Department of Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Yucai Zhang
- Department of Critical Care Medicine, Shanghai Children's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200062, China
| | - Chunxia Wang
- Institute of Pediatric Infection, Immunity, and Critical Care Medicine, Shanghai Children's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200062, China
- Institute of Pediatric Critical Care, Shanghai Jiao Tong University, Shanghai 200062, China
| | - Jiao Liu
- Department of Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
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8
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Zhu S, Nguyen A, Pang J, Zhao J, Chen Z, Liang Z, Gu Y, Huynh H, Bao Y, Lee S, Kluger Y, Ouyang K, Evans SM, Fang X. Mitochondrial Stress Induces an HRI-eIF2α Pathway Protective for Cardiomyopathy. Circulation 2022; 146:1028-1031. [PMID: 36154620 PMCID: PMC9523491 DOI: 10.1161/circulationaha.122.059594] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Siting Zhu
- Department of Medicine, University of California San Diego, La Jolla, California, USA
- Department of Cardiovascular Surgery, Peking University Shenzhen Hospital, School of Chemical Biology and Biotechnology, State Key Laboratory of Chemical Oncogenomics, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Anh Nguyen
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Jing Pang
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Jun Zhao
- Department of Pathology, Yale School of Medicine, New Haven, CT, USA
| | - Ze’e Chen
- Department of Medicine, University of California San Diego, La Jolla, California, USA
- Department of Cardiovascular Surgery, Peking University Shenzhen Hospital, School of Chemical Biology and Biotechnology, State Key Laboratory of Chemical Oncogenomics, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Zhengyu Liang
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Yusu Gu
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Helen Huynh
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Yutong Bao
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Sharon Lee
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Yuval Kluger
- Department of Pathology, Yale School of Medicine, New Haven, CT, USA
| | - Kunfu Ouyang
- Department of Cardiovascular Surgery, Peking University Shenzhen Hospital, School of Chemical Biology and Biotechnology, State Key Laboratory of Chemical Oncogenomics, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Sylvia M Evans
- Department of Medicine, University of California San Diego, La Jolla, California, USA
- Department of Pharmacology, University of California San Diego, La Jolla, California, USA
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, USA
| | - Xi Fang
- Department of Medicine, University of California San Diego, La Jolla, California, USA
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9
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Wang M, Lu Y, Wang H, Wu Y, Xu X, Li Y. High ATF4 Expression Is Associated With Poor Prognosis, Amino Acid Metabolism, and Autophagy in Gastric Cancer. Front Oncol 2022; 11:740120. [PMID: 34976799 PMCID: PMC8718699 DOI: 10.3389/fonc.2021.740120] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 11/19/2021] [Indexed: 12/30/2022] Open
Abstract
Background The role of activating transcription factor 4 (ATF4) underlying gastric cancer (GC) remains unclear. The purpose of this study was to investigate the expression levels and biological functions of ATF4 in GC. Methods Expression of ATF4 was detected by quantitative PCR (qPCR), Western blotting, and immunohistochemistry. Cox regression was used for survival analysis and the construction of the nomogram. Immunofluorescence was used to identify the intracellular localization of ATF4. Knockdown and overexpression of ATF4 in GC cells followed by wound healing and Transwell assays, EdU and Calcein-AM/propidium iodide (PI) staining, and cell cycle detection were performed to examine its function in vitro. Transmission electron microscopy was performed to assess the autophagy levels upon ATF4 silencing. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis and gene set enrichment analysis (GSEA) were used to determine gene enrichment. SPSS 22.0 software, GraphPad Prism 7.0, and R version 3.6.1 were used for statistical analysis. Results ATF4 expression was upregulated in GC cells and tissues compared with corresponding normal tissues. Survival analysis suggested that a high ATF4 expression was strongly associated with worse overall survival (OS) of GC patients (p < 0.001). The nomogram and the receiver operating characteristic (ROC) curves demonstrated that ATF4 was a highly sensitive and specific prognostic marker of GC [C-index = 0.797, area under the ROC curve (AUC) of 3-year OS = 0.855, and AUC of 5-year OS = 0.863]. In addition, ATF4 knockdown inhibited the cell proliferation, migration, invasion, and cell cycle progression of GC cells in vitro, while overexpression of ATF4 exerted the opposite effects. Bioinformatics analysis showed that ATF4 could promote GC progression possibly by regulating asparagine (Asn) metabolism and autophagy pathways. Further experiments indicated that ATF4 expression was significantly positively correlated with ASNS expression. The inhibition of cell clone formation in Asn-deprived conditions was more significant in the shATF4 group. Finally, we found that ATF4 promoted autophagy through regulating the mTORC1 pathway in GC cells. Conclusion These findings suggested that ATF4 can significantly promote GC development and serve as an independent prognostic factor for GC.
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Affiliation(s)
- Mingliang Wang
- General Surgery Department, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Yida Lu
- General Surgery Department, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Huizhen Wang
- General Surgery Department, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Youliang Wu
- General Surgery Department, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Xin Xu
- General Surgery Department, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Yongxiang Li
- General Surgery Department, The First Affiliated Hospital of Anhui Medical University, Hefei, China
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10
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Yasuda H, Tanaka M, Nishinaka A, Nakamura S, Shimazawa M, Hara H. Role of Activating Transcription Factor 4 in Murine Choroidal Neovascularization Model. Int J Mol Sci 2021; 22:8890. [PMID: 34445595 DOI: 10.3390/ijms22168890] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/17/2021] [Accepted: 08/17/2021] [Indexed: 12/04/2022] Open
Abstract
Neovascular age-related macular degeneration (nAMD) featuring choroidal neovascularization (CNV) is the principal cause of irreversible blindness in elderly people in the world. Integrated stress response (ISR) is one of the intracellular signals to be adapted to various stress conditions including endoplasmic reticulum (ER) stress. ISR signaling results in the upregulation of activating transcription factor 4 (ATF4), which is a mediator of ISR. Although recent studies have suggested ISR contributes to the progression of some age-related disorders, the effects of ATF4 on the development of CNV remain unclear. Here, we performed a murine model of laser-induced CNV and found that ATF4 was highly expressed in endothelial cells of the blood vessels of the CNV lesion site. Exposure to integrated stress inhibitor (ISRIB) reduced CNV formation, vascular leakage, and the upregulation of vascular endothelial growth factor (VEGF) in retinal pigment epithelium (RPE)-choroid-sclera complex. In human retinal microvascular endothelial cells (HRMECs), ISRIB reduced the level of ATF4 and VEGF induced by an ER stress inducer, thapsigargin, and recombinant human VEGF. Moreover, ISRIB decreased the VEGF-induced cell proliferation and migration of HRMECs. Collectively, our findings showed that pro-angiogenic effects of ATF4 in endothelial cells may be a potentially therapeutic target for patients with nAMD.
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11
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Chen L, Liu X, Zhou H, Li G, Huang F, Zhang J, Xia T, Lei W, Zhao J, Li C, Chen M. Activating transcription factor 4 regulates angiogenesis under lipid overload via methionine adenosyltransferase 2A-mediated endothelial epigenetic alteration. FASEB J 2021; 35:e21612. [PMID: 33948996 DOI: 10.1096/fj.202100233r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/19/2021] [Accepted: 04/06/2021] [Indexed: 02/05/2023]
Abstract
Lipid overload is intimately connected with the change of endothelial epigenetic status which impacts cellular signaling activities and endothelial function. Activating transcription factor 4 (ATF4) is involved in the regulation of lipid metabolism and meanwhile an epigenetic modifier. However, the role of ATF4 in the angiogenesis under lipid overload is not well understood. Here, to induce lipid overload status, we employed high-fat diet (HFD)-induced obese mouse model in vivo and palmitic acid (PA) to stimulate endothelial cells in vitro. Compared with mice fed with normal chow diet (NCD), HFD-induced obese mice showed angiogenic defects evidenced by decline in (1) blood flow recovery after hind limb ischemia, (2) wound healing speed after skin injury, (3) capillary density in injured tissues and matrigel plugs, and (4) endothelial sprouts of aortic ring. ATF4 deficiency aggravated above angiogenic defects in mice while ATF4 overexpression improved the blunted angiogenic response. Mechanistically, lipid overload lowered the H3K4 methylation levels at the regulatory regions of NOS3 and ERK1 genes, leading to reduced angiogenic signaling activity. Methionine adenosyltransferase 2A (MAT2A) is identified as a target of ATF4 and formed complex with ATF4 to direct lysine methyltransferase 2A (MLL1) to the regulatory regions of both genes for the maintenance of the H3K4 methylation level and angiogenic signaling activity. Here, we uncovered a novel metabolic-epigenetic coupling orchestrated by the ATF4-MAT2A axis for angiogenesis. The ATF4-MAT2A axis links lipid overload milieu to altered epigenetic status of relevant angiogenic signaling in endothelial cells, suggesting a potential therapeutic target for angiogenesis impaired by lipid overload.
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Affiliation(s)
- Li Chen
- Laboratory of Cardiovascular Disease, Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Xiaojing Liu
- Laboratory of Cardiovascular Disease, Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Hao Zhou
- Laboratory of Cardiovascular Disease, Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Guoyong Li
- Department of Cardiology, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Fangyang Huang
- Department of Cardiology, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Jialiang Zhang
- Department of Cardiology, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Tianli Xia
- Department of Cardiology, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Wenhua Lei
- Laboratory of Cardiovascular Disease, Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, P.R. China.,Department of Cardiology, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Jiahao Zhao
- Laboratory of Cardiovascular Disease, Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Changming Li
- Department of Cardiology, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Mao Chen
- Department of Cardiology, West China Hospital, Sichuan University, Chengdu, P.R. China
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12
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Bao J, Qian Z, Liu L, Hong X, Che H, Wu X. Pharmacological Disruption of Phosphorylated Eukaryotic Initiation Factor-2α/ Activating Transcription Factor 4/Indian Hedgehog Protects Intervertebral Disc Degeneration via Reducing the Reactive Oxygen Species and Apoptosis of Nucleus Pulposus Cells. Front Cell Dev Biol 2021; 9:675486. [PMID: 34164397 PMCID: PMC8215438 DOI: 10.3389/fcell.2021.675486] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 04/20/2021] [Indexed: 12/29/2022] Open
Abstract
Excessive reactive oxygen species (ROS) and apoptosis in nucleus pulposus (NP) cells accelerate the process of intervertebral disc degeneration (IDD). Here, we integrated pathological samples and in vitro and in vivo framework to investigate the impact of phosphorylation of eukaryotic initiation factor-2α (eIF2α)/activating transcription factor 4 (ATF4)/Indian hedgehog (Ihh) signaling in the IDD. From the specimen analysis of the IDD patients, we found phosphorylated eIF2α (p-eIF2α), ATF4 and Ihh protein levels were positively related while the NP tissue went degenerative. In vitro, tumor necrosis factor (TNF)-α caused the NP cell degeneration and induced a cascade of upregulation of p-eIF2α, ATF4, and Ihh. Interestingly, ATF4 could enhance Ihh expression through binding its promoter region, and silencing of ATF4 decreased Ihh and protected the NP cells from degeneration. Moreover, ISRIB inhibited the p-eIF2α, which resulted in a suppression of ATF4/Ihh, and alleviated the TNF-α-induced ROS production and apoptosis of NP cells. On the contrary, further activating p-eIF2α aggravated the NP cell degeneration, with amplification of ATF4/Ihh and a higher level of ROS and apoptosis. Additionally, applying cyclopamine (CPE) to suppress Ihh was efficient to prevent NP cell apoptosis but did not decrease the ROS level. In an instability-induced IDD model in mice, ISRIB suppressed p-eIF2α/ATF4/Ihh and prevented IDD via protecting the anti-oxidative enzymes and decreased the NP cell apoptosis. CPE prevented NP cell apoptosis but did not affect anti-oxidative enzyme expression. Taken together, p-eIF2α/ATF4/Ihh signaling involves the ROS level and apoptosis in NP cells, the pharmacological disruption of which may provide promising methods in preventing IDD.
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Affiliation(s)
- Junping Bao
- Spine Center, The Affiliated Zhongda Hospital of Southeast University, Nanjing, China.,School of Medicine, Southeast University, Nanjing, China
| | - Zhanyang Qian
- Spine Center, The Affiliated Zhongda Hospital of Southeast University, Nanjing, China.,School of Medicine, Southeast University, Nanjing, China
| | - Lei Liu
- Spine Center, The Affiliated Zhongda Hospital of Southeast University, Nanjing, China.,School of Medicine, Southeast University, Nanjing, China
| | - Xin Hong
- Spine Center, The Affiliated Zhongda Hospital of Southeast University, Nanjing, China.,School of Medicine, Southeast University, Nanjing, China
| | - Hui Che
- Faculty of Medicine, Medical Center, Albert-Ludwigs-University of Freiburg, Freiburg im Breisgau, Germany
| | - Xiaotao Wu
- Spine Center, The Affiliated Zhongda Hospital of Southeast University, Nanjing, China.,School of Medicine, Southeast University, Nanjing, China
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13
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Pereira RO, Marti A, Olvera AC, Tadinada SM, Bjorkman SH, Weatherford ET, Morgan DA, Westphal M, Patel PH, Kirby AK, Hewezi R, Bùi Trân W, García-Peña LM, Souvenir RA, Mittal M, Adams CM, Rahmouni K, Potthoff MJ, Abel ED. OPA1 deletion in brown adipose tissue improves thermoregulation and systemic metabolism via FGF21. eLife 2021; 10:e66519. [PMID: 33944779 PMCID: PMC8128440 DOI: 10.7554/elife.66519] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 05/02/2021] [Indexed: 12/14/2022] Open
Abstract
Adrenergic stimulation of brown adipocytes alters mitochondrial dynamics, including the mitochondrial fusion protein optic atrophy 1 (OPA1). However, direct mechanisms linking OPA1 to brown adipose tissue (BAT) physiology are incompletely understood. We utilized a mouse model of selective OPA1 deletion in BAT (OPA1 BAT KO) to investigate the role of OPA1 in thermogenesis. OPA1 is required for cold-induced activation of thermogenic genes in BAT. Unexpectedly, OPA1 deficiency induced fibroblast growth factor 21 (FGF21) as a BATokine in an activating transcription factor 4 (ATF4)-dependent manner. BAT-derived FGF21 mediates an adaptive response by inducing browning of white adipose tissue, increasing resting metabolic rates, and improving thermoregulation. However, mechanisms independent of FGF21, but dependent on ATF4 induction, promote resistance to diet-induced obesity in OPA1 BAT KO mice. These findings uncover a homeostatic mechanism of BAT-mediated metabolic protection governed in part by an ATF4-FGF21 axis, which is activated independently of BAT thermogenic function.
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Affiliation(s)
- Renata O Pereira
- Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, United States
| | - Alex Marti
- Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, United States
| | - Angela Crystal Olvera
- Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, United States
| | - Satya Murthy Tadinada
- Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, United States
| | - Sarah Hartwick Bjorkman
- Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, United States
- Department of Obstetrics and Gynecology, Reproductive Endocrinology and Infertility, Roy J. and Lucille A. Carver College of Medicine, Iowa City, United States
| | - Eric Thomas Weatherford
- Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, United States
| | - Donald A Morgan
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, United States
| | - Michael Westphal
- Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, United States
| | - Pooja H Patel
- Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, United States
| | - Ana Karina Kirby
- Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, United States
| | - Rana Hewezi
- Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, United States
| | - William Bùi Trân
- Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, United States
| | - Luis Miguel García-Peña
- Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, United States
| | - Rhonda A Souvenir
- Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, United States
| | - Monika Mittal
- Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, United States
| | - Christopher M Adams
- Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, United States
| | - Kamal Rahmouni
- Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, United States
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, United States
| | - Matthew J Potthoff
- Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, United States
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, United States
| | - E Dale Abel
- Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, United States
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14
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Ying Y, Xue R, Yang Y, Zhang SX, Xiao H, Zhu H, Li J, Chen G, Ye Y, Yu M, Liu X, Zhong Y. Activation of ATF4 triggers trabecular meshwork cell dysfunction and apoptosis in POAG. Aging (Albany NY) 2021; 13:8628-8642. [PMID: 33714955 PMCID: PMC8034903 DOI: 10.18632/aging.202677] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 02/01/2021] [Indexed: 11/28/2022]
Abstract
Primary open angle glaucoma (POAG) is the leading cause of irreversible blindness. Dysfunction of the trabecular meshwork (TM), resulting in decreased outflow of aqueous humor and increased intraocular pressure (IOP), plays an important role in the pathogenesis of POAG. However, the underlying mechanisms still remain unclear. In this study, we demonstrated that the eIF2-α/ATF4/CHOP branch of unfolded protein response (UPR) was activated in human trabecular meshwork cells (HTMCs) upon tert-butyl hydroperoxide (TBHP) exposure. Inhibition of ATF4 ameliorated TBHP-induced apoptosis and inflammatory cytokine production, while ectopic expression of ATF4 increased the expression of endothelial leukocyte adhesion molecule (ELAM)-1 and IL-8 in HTMCs. Furthermore, we found that ATF4 inhibition reduced tunicamycin-induced caspase-3 activation, ROS production, ELAM-1 expression, and HTMCs phagocytosis impairment. By an in vivo study in mice, we showed that overexpression of ATF4 in the TM induced C/EBP homologous protein (CHOP) expression and TM cells apoptosis, contributing to inflammatory cytokine production, and probably IOP elevation. More importantly, upregulation of ATF4 and CHOP, and colocalization of ATF4 with ELAM-1 were found in the TM of POAG patients. These results suggest that ATF4 is a critical mediator of oxidative stress and ER stress-induced TM cell dysfunction and apoptosis in POAG.
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Affiliation(s)
- Ying Ying
- Department of Physiology, Shenzhen University Health Science Center, Shenzhen University, Shenzhen, Guangdong, China
| | - Ran Xue
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Yangfan Yang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Sarah X Zhang
- Department of Ophthalmology and Ross Eye Institute, University at Buffalo, State University of New York, Buffalo, NY 14209, USA.,SUNY Eye Institute, State University of New York, New York, NY 10036, USA.,Department of Biochemistry, University at Buffalo, State University of New York, Buffalo, NY 14203, USA
| | - Hui Xiao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Huazhang Zhu
- Department of Physiology, Shenzhen University Health Science Center, Shenzhen University, Shenzhen, Guangdong, China
| | - Jingming Li
- Department of Ophthalmology, The First Affiliated Hospital of Xi'an Jiaotong University College of Medicine, Xi an, Shanxi, China
| | - Guo Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Yiming Ye
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Minbin Yu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Xing Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Yimin Zhong
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, China
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15
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Takahashi N, Harada M, Azhary JMK, Kunitomi C, Nose E, Terao H, Koike H, Wada-Hiraike O, Hirata T, Hirota Y, Koga K, Fujii T, Osuga Y. Accumulation of advanced glycation end products in follicles is associated with poor oocyte developmental competence. Mol Hum Reprod 2020; 25:684-694. [PMID: 31504800 DOI: 10.1093/molehr/gaz050] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 07/14/2019] [Accepted: 08/12/2019] [Indexed: 12/13/2022] Open
Abstract
Advanced glycation end products (AGEs) affect the follicular microenvironment. The close relationship between AGEs, proinflammatory cytokine production and activation of the unfolded protein response (UPR), which involves activating transcription factor 4 (ATF4), is crucial for regulation of various cellular functions. We examined whether accumulation of AGEs in follicles was associated with proinflammatory cytokine production and activation of the UPR in granulosa cells and decreased oocyte developmental competence. Concentrations of AGEs, soluble receptor for AGE (sRAGE), interleukin (IL)-6 and IL-8 in follicular fluid (FF) were examined by ELISAs in 50 follicles. mRNA expression of ATF4, IL-6 and IL-8 in cumulus cells (CCs) were examined by quantitative RT-PCR in 77 samples. Cultured human granulosa-lutein cells (GLCs) were treated with AGE-bovine serum albumin (BSA) alone or following transfection of ATF4-targeting small interfering RNA. The AGE concentration and the AGE/sRAGE ratio in FF were significantly higher in follicles containing oocytes that developed into poor-morphology embryos (group I) than those with good-morphology embryos (group II). When compared with sibling follicles from the same patients, the AGE/sRAGE and concentrations of IL-6 and IL-8 in FF, as well as ATF4, IL-6 and IL-8 mRNA expression in CCs, were significantly higher in group I follicles than group II. AGE treatment increased mRNA expression of ATF4, IL-6 and IL-8 in cultured GLCs. Knockdown of ATF4 abrogated the stimulatory effects of AGE on mRNA expression and protein secretion of IL-6 and IL-8. Our findings support the idea that accumulation of AGEs in follicles reduces oocyte competence by triggering inflammation via activation of ATF4 in the follicular microenvironment.
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Affiliation(s)
- Nozomi Takahashi
- Department of Obstetrics and Gynecology, Faculty of Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo, Tokyo, Japan
| | - Miyuki Harada
- Department of Obstetrics and Gynecology, Faculty of Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo, Tokyo, Japan
| | - Jerilee M K Azhary
- Department of Obstetrics and Gynecology, Faculty of Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo, Tokyo, Japan
| | - Chisato Kunitomi
- Department of Obstetrics and Gynecology, Faculty of Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo, Tokyo, Japan
| | - Emi Nose
- Department of Obstetrics and Gynecology, Faculty of Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo, Tokyo, Japan
| | - Hiromi Terao
- Department of Obstetrics and Gynecology, Faculty of Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo, Tokyo, Japan
| | - Hiroshi Koike
- Department of Obstetrics and Gynecology, Faculty of Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo, Tokyo, Japan
| | - Osamu Wada-Hiraike
- Department of Obstetrics and Gynecology, Faculty of Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo, Tokyo, Japan
| | - Tetsuya Hirata
- Department of Obstetrics and Gynecology, Faculty of Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo, Tokyo, Japan
| | - Yasushi Hirota
- Department of Obstetrics and Gynecology, Faculty of Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo, Tokyo, Japan
| | - Kaori Koga
- Department of Obstetrics and Gynecology, Faculty of Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo, Tokyo, Japan
| | - Tomoyuki Fujii
- Department of Obstetrics and Gynecology, Faculty of Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo, Tokyo, Japan
| | - Yutaka Osuga
- Department of Obstetrics and Gynecology, Faculty of Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo, Tokyo, Japan
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16
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Abstract
Primary Effusion Lymphoma (PEL) is a rare and aggressive B-lymphoma caused by Kaposi's sarcoma-associated herpes virus (KSHV) infection that occurs in immunocompromised patients. PEL patients have a poor prognosis. KSHV modulates various cellular signaling pathways to maintain latent infection, and causes malignant conversion of host cells. We previously reported that capsaicin suppressed extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) signaling and induced apoptosis in PEL. Generally, cellular stress such as nutrient starvation, oxidation and virus infection induce CCAAT/enhancer binding protein (C/EBP) homologous protein (CHOP) expression by activating transcription factor 4 (ATF4), however endoplasmic reticulum (ER) stress induces CHOP expression by both ATF4 and ATF6. CHOP is associated with apoptosis induction and upregulates growth arrest and DNA damage-inducible protein 34 (GADD34) and p53 up-regulated modulator of apoptosis (PUMA) mRNA expression. In this study, we found a new mechanism in which capsaicin induces apoptosis via ATF4-CHOP-PUMA. Capsaicin promoted transcriptional activation of CHOP, which increased mRNA expression of GADD34 and PUMA, resulting in PEL apoptosis. Furthermore, capsaicin increased ATF4 protein levels by promoting ATF4 translation, not transcription, and had no effect on ATF6-dependent transcriptional activation. In sum, capsaicin promotes ATF4 translation and transcriptional induction of CHOP, which results in PUMA expression and apoptosis in PEL cells.
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17
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Zhong WQ, Li ZZ, Jiang H, Zou YP, Wang HT, Cai Y, Zhao Y, Zhao JH. Elevated ATF4 Expression in Odontogenic Keratocysts Epithelia: Potential Involvement in Tissue Hypoxia and Stromal M2 Macrophage Infiltration. J Histochem Cytochem 2019; 67:801-812. [PMID: 31424999 DOI: 10.1369/0022155419871550] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The aim of this study was to investigate the expression of the activating transcription factor 4 (ATF4) in odontogenic keratocysts (OKC), its association with hypoxia and M2-polarized macrophages infiltration, and its potential relationships with angiogenesis in OKC. The expression of ATF4, hypoxia-inducible factor 1α (HIF-1α), macrophage colony-stimulating factor (M-CSF), and receptor activator of nuclear factor κ-B ligand (RANKL) in OKC samples and normal oral mucosa (OM) was detected by immunohistochemistry. Meanwhile, microvessel density (MVD) was measured using antibody against CD31. M2-polarized macrophages were identified using double-staining for CD68+ and CD163+. The correlations of ATF4 with HIF-1α, M-CSF, and M2-polarized macrophages infiltration were determined by Spearman's rank correlation test and hierarchical clustering. Human immortalized oral epithelial cells (HIOECs) were used in in vitro experiments. Our data showed that the expression of HIF-1α, ATF4, and M-CSF was significantly upregulated in the epithelium of OKC when compared with the OM. The expression of ATF4 was positively correlated with that of HIF-1α, M-CSF, MVD, and M2-polarized macrophages infiltration. Elevated expression of ATF4 in the epithelial lining of OKC may facilitate the M2 macrophages infiltration in response to hypoxia, leading to the development of OKC.
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Affiliation(s)
- Wen-Qun Zhong
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China.,Department of Oral and Maxillofacial Surgery, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Zhi-Zheng Li
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Hao Jiang
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Yan-Ping Zou
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Hai-Tao Wang
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Yu Cai
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China.,Department of Oral and Maxillofacial Surgery, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Yi Zhao
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China.,Department of Prosthodontics, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Ji-Hong Zhao
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China.,Department of Oral and Maxillofacial Surgery, School & Hospital of Stomatology, Wuhan University, Wuhan, China
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18
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Ou L, Sun T, Cheng Y, Huang L, Zhan X, Zhang P, Yang J, Zhang Y, Zhou Z. MicroRNA-214 contributes to regulation of necroptosis via targeting ATF4 in diabetes-associated periodontitis. J Cell Biochem 2019; 120:14791-14803. [PMID: 31090954 DOI: 10.1002/jcb.28740] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2018] [Revised: 02/01/2019] [Accepted: 02/14/2019] [Indexed: 12/26/2022]
Abstract
Diabetes and periodontal diseases have a mutual promoting relationship that induces severe tissue damage and cell death. The potential roles of microRNAs (miRNAs) and the type of cell death involved in diabetes-associated periodontitis are obscure. The gingival tissues of patients were obtained and MC3T3-E1 cells were costimulated with high glucose and lipopolysaccharide (LPS). Osseous morphometric analysis was evaluated with micro-CT, and histological characteristics were measured by hematoxylin/eosin and immunohistochemical staining. Cytokine secretion was confirmed by enzyme-linked immunosorbent assay, and reactive oxygen species (ROS) was measured using a DCFH-DA probe kit. Gene expression was measured by real-time quantitative reverse transcription PCR (qRT-PCR), and protein expression was assessed by Western blot and immunofluorescence analysis. The miR-214 level, receptor-interacting serine-threonine protein (RIP) 1, RIP3, and phospho-mixed lineage kinase domain-like (p-MLKL) protein expression were elevated in the inflamed gingival tissues of diabetes-associated periodontitis patients, with activating transcription factor 4 (ATF4) expression showing the opposite effect. The high glucose (22 mM) could not induce significant increase of RIP1, RIP3, and p-MLKL; however, the high glucose and LPS (500-1000 ng/mL) cotreatment resulted in increase in the number of RIP1, RIP3, and p-MLKL in MC3T3-E1 cells. NAC (ROS inhibitor) inhibited RIP1, RIP3, and increased ATF4; however, necrostatin-1 (Nec-1) (RIP1 inhibitor) specifically inhibited the protein expression of RIP1 and RIP3 and had no influence on ATF4. The use of antagomir-214 suppressed the expression of miR-214, RIP1, RIP3, and p-MLKL, but increased ATF4 protein level in glucose and LPS-induced cells. ATF4 knockdown by ATF4 small interfering RNA offset the effect of antagomir-214. RIP1- and RIP3-dependent necroptosis was confirmed in the inflamed gingival tissues of diabetes-associated periodontitis patients and high glucose- and LPS- cotreated cells. It was suggested that miR-214-targeted ATF4 participated in the regulation of necroptosis in vivo and in vitro.
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Affiliation(s)
- Lingling Ou
- Department of Stomatology, The First Affiliated Hospital of Jinan University, Guangzhou, P.R. China
| | - Ting Sun
- Department of Stomatology, The First Affiliated Hospital of Jinan University, Guangzhou, P.R. China
| | - Yaodong Cheng
- Department of Stomatology, The First Affiliated Hospital of Jinan University, Guangzhou, P.R. China
| | - Linwei Huang
- Department of Stomatology, The First Affiliated Hospital of Jinan University, Guangzhou, P.R. China
| | - Xiaozhen Zhan
- Department of Stomatology, The First Affiliated Hospital of Jinan University, Guangzhou, P.R. China
| | - Peng Zhang
- Department of Pathology, Medical School of Yichun University, Yichun, Jiangxi, P.R. China
| | - Junjie Yang
- Department of Stomatology, The First Affiliated Hospital of Jinan University, Guangzhou, P.R. China
| | - Ye Zhang
- Department of Stomatology, The First Affiliated Hospital of Jinan University, Guangzhou, P.R. China
| | - Zhiying Zhou
- Department of Stomatology, The First Affiliated Hospital of Jinan University, Guangzhou, P.R. China
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19
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Haro D, Marrero PF, Relat J. Nutritional Regulation of Gene Expression: Carbohydrate-, Fat- and Amino Acid-Dependent Modulation of Transcriptional Activity. Int J Mol Sci 2019; 20:E1386. [PMID: 30893897 DOI: 10.3390/ijms20061386] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 03/12/2019] [Accepted: 03/13/2019] [Indexed: 12/21/2022] Open
Abstract
The ability to detect changes in nutrient levels and generate an adequate response to these changes is essential for the proper functioning of living organisms. Adaptation to the high degree of variability in nutrient intake requires precise control of metabolic pathways. Mammals have developed different mechanisms to detect the abundance of nutrients such as sugars, lipids and amino acids and provide an integrated response. These mechanisms include the control of gene expression (from transcription to translation). This review reports the main molecular mechanisms that connect nutrients’ levels, gene expression and metabolism in health. The manuscript is focused on sugars’ signaling through the carbohydrate-responsive element binding protein (ChREBP), the role of peroxisome proliferator-activated receptors (PPARs) in the response to fat and GCN2/activating transcription factor 4 (ATF4) and mTORC1 pathways that sense amino acid concentrations. Frequently, alterations in these pathways underlie the onset of several metabolic pathologies such as obesity, insulin resistance, type 2 diabetes, cardiovascular diseases or cancer. In this context, the complete understanding of these mechanisms may improve our knowledge of metabolic diseases and may offer new therapeutic approaches based on nutritional interventions and individual genetic makeup.
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20
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Zhou Y, Liu X, Li W, Sun X, Xie Z. Endoplasmic reticulum stress contributes to the pathogenesis of stress urinary incontinence in postmenopausal women. J Int Med Res 2018; 46:5269-5277. [PMID: 30426803 PMCID: PMC6300970 DOI: 10.1177/0300060518807602] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Objective To investigate the relationship between endoplasmic reticulum stress (ERS) and the pathogenesis of stress urinary incontinence (SUI) in postmenopausal women. Methods Anterior vaginal wall tissue was collected from postmenopausal women with SUI and control subjects. Western blotting was performed for glucose-regulated protein (GRP78), inositol-requiring enzyme 1(IRE1), protein kinase-like endoplasmic reticulum kinase (PERK), activating transcription factor 6 (ATF6), C/EBP-homologous protein (CHOP), and B-cell lymphoma 2 (Bcl-2). Additionally, mRNA expression levels of PERK, activating transcription factor 4 (ATF4), and CHOP were examined by real-time polymerase chain reaction. Results GRP78 protein and mRNA expression levels were significantly lower in women with SUI, compared with control subjects. PERK and p-PERK expression levels were higher in women with SUI than in control subjects. However, no differences in IRE1 or ATF6 expression levels were observed in either group. Notably, higher CHOP and lower Bcl-2 protein expression levels were detected in women with SUI, compared with control subjects. Furthermore, PERK, ATF4, and CHOP mRNA expression levels were significantly higher in women with SUI than in control subjects. Conclusions Alterations of ERS markers in SUI suggest that ERS may be involved in the development of SUI in postmenopausal women.
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Affiliation(s)
- Yong Zhou
- Department of Gynecology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, People's Republic of China
| | - Xiaoxia Liu
- Department of Gynecology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, People's Republic of China
| | - Wenjuan Li
- Department of Gynecology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, People's Republic of China
| | - Xiaoyan Sun
- Department of Gynecology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, People's Republic of China
| | - Zhenwei Xie
- Department of Gynecology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, People's Republic of China
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21
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Huo JF, Chen XB. P2X4R silence suppresses glioma cell growth through BDNF/TrkB/ATF4 signaling pathway. J Cell Biochem 2018; 120:6322-6329. [PMID: 30362154 DOI: 10.1002/jcb.27919] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 09/27/2018] [Indexed: 02/06/2023]
Abstract
Purinergic receptor P2X 4 (P2X4R), a member of purinergic channels family and a subtype of ionotropic adenosine triphosphate receptors, plays a critical role in tumorigenesis. Evidence suggested that P2X4R is expressed in rat C6 glioma model, however, its role and the underlying mechanism of action are still unclear in human glioblastoma multiforme (GBM). In the current study, our aim is to examine the function and the molecular basis of P2X4R in GBM. We first observed that GBM cells, U251, T98, U87, U373, and A172 were all high expressed P2X4R, when compared with the normal human astrocytes (NHA) cells. To gain the function of P2X4R, P2X4R silence cells were constructed by transfection with P2X4R small interfering RNA (siRNA). We found that P2X4R deletion impeded T98 and U87 cell viability and proliferation, and further studies indicated that cell apoptosis and caspase-3 activity was increased in T98 and U87 cell transfected with P2X4R siRNA. Subsequently, we confirmed that P2X4R silence suppressed brain-derived neurotrophic factor (BDNF), Trk receptor tyrosine kinases (TrkB), and activating transcription factor 4 (ATF4) expression in T98 and U87 cells. And P2X4R siRNA-induced ATF4-expression inhibition dependent on BDNF/TrkB signaling pathway. The impact of P2X4R silence on T98 and U87 cell growth and apoptosis was reversed by ATF4 overexpression. In summary, this study provides the first evidence that P2X4R plays important roles in GBM cell growth and apoptosis.
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Affiliation(s)
- Jun-Feng Huo
- Second Ward, Department of Neurosurgery, Huaihe Hospital of Henan University, Kaifeng, China
| | - Xiao-Bing Chen
- Second Ward, Department of Neurosurgery, Huaihe Hospital of Henan University, Kaifeng, China
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22
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Wu K, Huang J, Li N, Xu T, Cai W, Ye Z. Antitumor effect of ginsenoside Rg3 on gallbladder cancer by inducing endoplasmic reticulum stress-mediated apoptosis in vitro and in vivo. Oncol Lett 2018; 16:5687-5696. [PMID: 30344724 PMCID: PMC6176246 DOI: 10.3892/ol.2018.9331] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 07/05/2018] [Indexed: 12/18/2022] Open
Abstract
Recent studies have highlighted the importance of the endoplasmic reticulum (ER) in apoptotic processes. In the present study, the traditional herbal medicine ginsenoside Rg3 was used to treat gallbladder cancer in vitro and in vivo. The underlying signaling mechanisms were investigated using various molecular biology techniques, including flow cytometry, western blot analysis, ELISA and reverse transcription-quantitative polymerase chain reaction (RT-qPCR). It was indicated that Rg3 exerted pro-apoptotic activity against the gallbladder cancer cell line GBC-SD through the ER stress-mediated signaling pathway. This was demonstrated by increased expression of phosphorylation of eukaryotic translation-initiation factor 2α (eIF2α), activating transcription factor 4 (ATF4), CCAAT/enhancer-binding protein homologous protein and lipocalin 2. In addition, eIF2α and ATF4 knockdown attenuated the pro-apoptotic effect of Rg3 by inhibiting reactive oxygen species. Furthermore, the results of RT-qPCR analysis indicated that long intergenic non-protein coding RNA-p21 was significantly upregulated following Rg3 treatment. In conclusion, the results of the present study demonstrated that Rg3 inhibited tumor growth in a GBC-SD gallbladder cancer xenograft, by upregulating the ER stress-mediated signaling pathway. Therefore, ER stress activation is suggested to mediate the antitumor effect of Rg3 in gallbladder cancer activity in vitro and in vivo.
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Affiliation(s)
- Keren Wu
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310006, P.R. China
| | - Jie Huang
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310006, P.R. China
| | - Ning Li
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310006, P.R. China
| | - Tao Xu
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310006, P.R. China
| | - Wenyu Cai
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310006, P.R. China
| | - Zhipeng Ye
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310006, P.R. China
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23
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Rajesh K, Krishnamoorthy J, Gupta J, Kazimierczak U, Papadakis AI, Deng Z, Wang S, Kuninaka S, Koromilas AE. The eIF2α serine 51 phosphorylation-ATF4 arm promotes HIPPO signaling and cell death under oxidative stress. Oncotarget 2018; 7:51044-51058. [PMID: 27409837 PMCID: PMC5239457 DOI: 10.18632/oncotarget.10480] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 06/23/2016] [Indexed: 11/25/2022] Open
Abstract
The HIPPO pathway is an evolutionary conserved regulator of organ size that controls both cell proliferation and death. This pathway has an important role in mediating cell death in response to oxidative stress through the inactivation of Yes-associated protein (YAP) and inhibition of anti-oxidant gene expression. Cells exposed to oxidative stress induce the phosphorylation of the alpha (α) subunit of the translation initiation factor eIF2 at serine 51 (eIF2αP), a modification that leads to the general inhibition of mRNA translation initiation. Under these conditions, increased eIF2αP facilitates the mRNA translation of activating transcription factor 4 (ATF4), which mediates either cell survival and adaptation or cell death under conditions of severe stress. Herein, we demonstrate a functional connection between the HIPPO and eIF2αP-ATF4 pathways under oxidative stress. We demonstrate that ATF4 promotes the stabilization of the large tumor suppressor 1 (LATS1), which inactivates YAP by phosphorylation. ATF4 inhibits the expression of NEDD4.2 and WWP1 mRNAs under pro-oxidant conditions, which encode ubiquitin ligases mediating the proteasomal degradation of LATS1. Increased LATS1 stability is required for the induction of cell death under oxidative stress. Our data reveal a previously unidentified ATF4-dependent pathway in the induction of cell death under oxidative stress via the activation of LATS1 and HIPPO pathway.
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Affiliation(s)
- Kamindla Rajesh
- Lady Davis Institute for Medical Research, McGill University, Sir Mortimer B. Davis-Jewish General Hospital, Montreal, Quebec, Canada
| | - Jothilatha Krishnamoorthy
- Lady Davis Institute for Medical Research, McGill University, Sir Mortimer B. Davis-Jewish General Hospital, Montreal, Quebec, Canada
| | - Jyotsana Gupta
- Lady Davis Institute for Medical Research, McGill University, Sir Mortimer B. Davis-Jewish General Hospital, Montreal, Quebec, Canada
| | - Urszula Kazimierczak
- Lady Davis Institute for Medical Research, McGill University, Sir Mortimer B. Davis-Jewish General Hospital, Montreal, Quebec, Canada.,Department of Cancer Immunology, Poznan University of Medical Sciences, Poznan, Poland
| | - Andreas I Papadakis
- Lady Davis Institute for Medical Research, McGill University, Sir Mortimer B. Davis-Jewish General Hospital, Montreal, Quebec, Canada
| | - Zhilin Deng
- Lady Davis Institute for Medical Research, McGill University, Sir Mortimer B. Davis-Jewish General Hospital, Montreal, Quebec, Canada
| | - Shuo Wang
- Lady Davis Institute for Medical Research, McGill University, Sir Mortimer B. Davis-Jewish General Hospital, Montreal, Quebec, Canada
| | - Shinji Kuninaka
- Division of Gene Regulation, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, Japan
| | - Antonis E Koromilas
- Lady Davis Institute for Medical Research, McGill University, Sir Mortimer B. Davis-Jewish General Hospital, Montreal, Quebec, Canada.,Department of Oncology, Faculty of Medicine, McGill University, Montreal, Quebec, Canada
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24
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Panda DK, Bai X, Sabbagh Y, Zhang Y, Zaun HC, Karellis A, Koromilas AE, Lipman ML, Karaplis AC. Defective interplay between mTORC1 activity and endoplasmic reticulum stress-unfolded protein response in uremic vascular calcification. Am J Physiol Renal Physiol 2018; 314:F1046-F1061. [PMID: 29357413 DOI: 10.1152/ajprenal.00350.2017] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Vascular calcification increases the risk of cardiovascular disease and death in patients with chronic kidney disease (CKD). Increased activity of mammalian target of rapamycin complex 1 (mTORC1) and endoplasmic reticulum (ER) stress-unfolded protein response (UPR) are independently reported to partake in the pathogenesis of vascular calcification in CKD. However, the association between mTORC1 activity and ER stress-UPR remains unknown. We report here that components of the uremic state [activation of the receptor for advanced glycation end products (RAGE) and hyperphosphatemia] potentiate vascular smooth muscle cell (VSMC) calcification by inducing persistent and exaggerated activity of mTORC1. This gives rise to prolonged and excessive ER stress-UPR as well as attenuated levels of sestrin 1 ( Sesn1) and Sesn3 feeding back to inhibit mTORC1 activity. Activating transcription factor 4 arising from the UPR mediates cell death via expression of CCAAT/enhancer-binding protein (c/EBP) homologous protein (CHOP), impairs the generation of pyrophosphate, a potent inhibitor of mineralization, and potentiates VSMC transdifferentiation to the osteochondrocytic phenotype. Short-term treatment of CKD mice with rapamycin, an inhibitor of mTORC1, or tauroursodeoxycholic acid, a bile acid that restores ER homeostasis, normalized mTORC1 activity, molecular markers of UPR, and calcium content of aortas. Collectively, these data highlight that increased and/or protracted mTORC1 activity arising from the uremic state leads to dysregulated ER stress-UPR and VSMC calcification. Manipulation of the mTORC1-ER stress-UPR pathway opens up new therapeutic strategies for the prevention and treatment of vascular calcification in CKD.
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Affiliation(s)
- Dibyendu K Panda
- Division of Nephrology, Department of Medicine and Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University , Montreal, Quebec , Canada
| | - Xiuying Bai
- Division of Endocrinology and Metabolism, Department of Medicine and Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University , Montreal, Quebec , Canada
| | - Yves Sabbagh
- Rare Disease, Sanofi Genzyme, Framingham, Massachusetts
| | - Yan Zhang
- Division of Nephrology, Department of Medicine and Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University , Montreal, Quebec , Canada
| | - Hans-Christian Zaun
- Division of Nephrology, Department of Medicine and Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University , Montreal, Quebec , Canada
| | - Angeliki Karellis
- Division of Endocrinology and Metabolism, Department of Medicine and Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University , Montreal, Quebec , Canada
| | - Antonis E Koromilas
- Department of Oncology and Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University , Montreal, Quebec , Canada
| | - Mark L Lipman
- Division of Nephrology, Department of Medicine and Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University , Montreal, Quebec , Canada
| | - Andrew C Karaplis
- Division of Endocrinology and Metabolism, Department of Medicine and Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University , Montreal, Quebec , Canada
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25
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Abstract
Activation of the endoplasmic reticulum (ER) stress and ER stress response, also known as the unfolded protein response (UPR), is common to various degenerative disorders. Therefore, signaling components of the UPR are currently emerging as potential targets for intervention and treatment of human diseases. One UPR signaling member, activating transcription factor 4 (ATF4), has been found up-regulated in many pathological conditions, pointing to therapeutic potential in targeting its expression. In cells, ATF4 governs multiple signaling pathways, including autophagy, oxidative stress, inflammation, and translation, suggesting a multifaceted role of ATF4 in the progression of various pathologies. However, ATF4 has been shown to trigger both pro-survival and pro-death pathways, and this, perhaps, can explain the contradictory opinions in current literature regarding targeting ATF4 for clinical application. In this review, we summarized recent published studies from our labs and others that focus on the therapeutic potential of the strategy controlling ATF4 expression in different retinal and neurodegenerative disorders.
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Affiliation(s)
- Priyamvada M Pitale
- Department of Optometry and Vision Science, School of Optometry, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Oleg Gorbatyuk
- Department of Optometry and Vision Science, School of Optometry, University of Alabama at Birmingham, Birmingham, AL, United States.,Department of Neurology, Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Marina Gorbatyuk
- Department of Optometry and Vision Science, School of Optometry, University of Alabama at Birmingham, Birmingham, AL, United States
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26
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Dai B, Yan T, Shen YX, Xu YJ, Shen HB, Chen D, Wang JR, He SH, Dong QR, Zhang AL. Edaravone protects against oxygen-glucose-serum deprivation/restoration-induced apoptosis in spinal cord astrocytes by inhibiting integrated stress response. Neural Regen Res 2017; 12:283-289. [PMID: 28400812 PMCID: PMC5361514 DOI: 10.4103/1673-5374.199006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
We previously found that oxygen-glucose-serum deprivation/restoration (OGSD/R) induces apoptosis of spinal cord astrocytes, possibly via caspase-12 and the integrated stress response, which involves protein kinase R-like endoplasmic reticulum kinase (PERK), eukaryotic initiation factor 2-alpha (eIF2α) and activating transcription factor 4 (ATF4). We hypothesized that edaravone, a low molecular weight, lipophilic free radical scavenger, would reduce OGSD/R-induced apoptosis of spinal cord astrocytes. To test this, we established primary cultures of rat astrocytes, and exposed them to 8 hours/6 hours of OGSD/R with or without edaravone (0.1, 1, 10, 100 μM) treatment. We found that 100 μM of edaravone significantly suppressed astrocyte apoptosis and inhibited the release of reactive oxygen species. It also inhibited the activation of caspase-12 and caspase-3, and reduced the expression of homologous CCAAT/enhancer binding protein, phosphorylated (p)-PERK, p-eIF2α, and ATF4. These results point to a new use of an established drug in the prevention of OGSD/R-mediated spinal cord astrocyte apoptosis via the integrated stress response.
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Affiliation(s)
- Bin Dai
- Department of Orthopedics, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China; Department of Orthopedics, Binhai County People's Hospital, Binhai, Jiangsu Province, China
| | - Ting Yan
- Safety Assessment and Research Center for Drug, Pesticide and Veterinary Drug of Jiangsu Province, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Yi-Xing Shen
- Department of Orthopedics, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - You-Jia Xu
- Department of Orthopedics, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - Hai-Bin Shen
- Department of Orthopedics, Binhai County People's Hospital, Binhai, Jiangsu Province, China
| | - Dong Chen
- Department of Orthopedics, Binhai County People's Hospital, Binhai, Jiangsu Province, China
| | - Jin-Rong Wang
- Department of Orthopedics, Binhai County People's Hospital, Binhai, Jiangsu Province, China
| | - Shuang-Hua He
- Department of Orthopedics, Third Affiliated Hospital of Soochow University, Changzhou, Jiangsu Province, China
| | - Qi-Rong Dong
- Department of Orthopedics, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - Ai-Liang Zhang
- Department of Orthopedics, Third Affiliated Hospital of Soochow University, Changzhou, Jiangsu Province, China
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Abstract
Aging impairs skeletal muscle protein synthesis, leading to muscle weakness and atrophy. However, the underlying molecular mechanisms remain poorly understood. Here, we review evidence that mammalian/mechanistic target of rapamycin complex 1 (mTORC1)-mediated and activating transcription factor 4 (ATF4)-mediated amino acid (AA) sensing pathways, triggered by impaired AA delivery to aged skeletal muscle, may play important roles in skeletal muscle aging. Interventions that alleviate age-related impairments in muscle protein synthesis, strength, and/or muscle mass appear to do so by reversing age-related changes in skeletal muscle AA delivery, mTORC1 activity, and/or ATF4 activity. An improved understanding of the mechanisms and roles of AA sensing pathways in skeletal muscle may lead to evidence-based strategies to attenuate sarcopenia.
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Affiliation(s)
- Tatiana Moro
- Department of Nutrition and Metabolism, University of Texas Medical Branch, Galveston, TX, USA; Sealy Center on Aging, University of Texas Medical Branch, Galveston, TX, USA
| | - Scott M Ebert
- Department of Internal Medicine, University of Iowa, Iowa City, IA, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA, USA; Iowa City Veterans Affairs Medical Center, Iowa City, IA, USA
| | - Christopher M Adams
- Department of Internal Medicine, University of Iowa, Iowa City, IA, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA, USA; Iowa City Veterans Affairs Medical Center, Iowa City, IA, USA
| | - Blake B Rasmussen
- Department of Nutrition and Metabolism, University of Texas Medical Branch, Galveston, TX, USA; Sealy Center on Aging, University of Texas Medical Branch, Galveston, TX, USA.
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28
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Pakos-Zebrucka K, Koryga I, Mnich K, Ljujic M, Samali A, Gorman AM. The integrated stress response. EMBO Rep 2016; 17:1374-1395. [PMID: 27629041 DOI: 10.15252/embr.201642195] [Citation(s) in RCA: 1399] [Impact Index Per Article: 174.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 08/23/2016] [Indexed: 02/06/2023] Open
Abstract
In response to diverse stress stimuli, eukaryotic cells activate a common adaptive pathway, termed the integrated stress response (ISR), to restore cellular homeostasis. The core event in this pathway is the phosphorylation of eukaryotic translation initiation factor 2 alpha (eIF2α) by one of four members of the eIF2α kinase family, which leads to a decrease in global protein synthesis and the induction of selected genes, including the transcription factor ATF4, that together promote cellular recovery. The gene expression program activated by the ISR optimizes the cellular response to stress and is dependent on the cellular context, as well as on the nature and intensity of the stress stimuli. Although the ISR is primarily a pro-survival, homeostatic program, exposure to severe stress can drive signaling toward cell death. Here, we review current understanding of the ISR signaling and how it regulates cell fate under diverse types of stress.
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Affiliation(s)
- Karolina Pakos-Zebrucka
- Apoptosis Research Centre, National University of Ireland Galway, Galway, Ireland School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Izabela Koryga
- Apoptosis Research Centre, National University of Ireland Galway, Galway, Ireland School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Katarzyna Mnich
- Apoptosis Research Centre, National University of Ireland Galway, Galway, Ireland School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Mila Ljujic
- Apoptosis Research Centre, National University of Ireland Galway, Galway, Ireland School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Afshin Samali
- Apoptosis Research Centre, National University of Ireland Galway, Galway, Ireland School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Adrienne M Gorman
- Apoptosis Research Centre, National University of Ireland Galway, Galway, Ireland School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
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29
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Atherton PJ, Greenhaff PL, Phillips SM, Bodine SC, Adams CM, Lang CH. Control of skeletal muscle atrophy in response to disuse: clinical/preclinical contentions and fallacies of evidence. Am J Physiol Endocrinol Metab 2016; 311:E594-604. [PMID: 27382036 PMCID: PMC5142005 DOI: 10.1152/ajpendo.00257.2016] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 07/05/2016] [Indexed: 01/08/2023]
Abstract
Muscle wasting resulting wholly or in part from disuse represents a serious medical complication that, when prolonged, can increase morbidity and mortality. Although much knowledge has been gained over the past half century, the underlying etiology by which disuse alters muscle proteostasis remains enigmatic. Multidisciplinary and novel methodologies are needed to fill gaps and overcome barriers to improved patient care. The present review highlights seminal concepts from a symposium at Experimental Biology 2016. These proceedings focus on 1) the role of insulin resistance in mediating disuse-induced changes in muscle protein synthesis (MPS) and breakdown (MPB), as well as cross-talk between carbohydrate and protein metabolism; 2) the relative importance of MPS/MPB in mediating involuntary muscle loss in humans and animals; 3) interpretative limitations associated with MPS/MPB "markers," e.g., MuRF1/MAFbx mRNA; and finally, 4) how OMIC technologies can be leveraged to identify molecular pathways (e.g., ATF4, p53, p21) mediating disuse atrophy. This perspective deals primarily with "simple atrophy" due to unloading. Nonetheless, it is likely that disuse is a pervasive contributor to muscle wasting associated with catabolic disease-related atrophy (i.e., due to associated sedentary behaviour of disease burden). Key knowledge gaps and challenges are identified to stimulate discussion and identify opportunities for translational research. Data from animal and human studies highlight both similarities and differences. Integrated preclinical and clinical research is encouraged to better understand the metabolic and molecular underpinnings and translational relevance,for disuse atrophy. These approaches are crucial to clinically prevent or reverse muscle atrophy, thereby reestablishing homeostasis and recovery.
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Affiliation(s)
- Philip J Atherton
- Royal Derby Medical School, Royal Derby Hospital, Derby, United Kingdom;
| | - Paul L Greenhaff
- MRC-ARUK Centre for Musculoskeletal Ageing Research, ARUK Centre for Sport, Exercise, and Osteoarthritis, School of Life Sciences, The Medical School, University of Nottingham, Nottingham, United Kingdom
| | - Stuart M Phillips
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Sue C Bodine
- Departments of Neurobiology, Physiology and Behavior, and Physiology and Membrane Biology, University of California Davis, Veterans Affairs Northern California Health Care System, Mather, California
| | - Christopher M Adams
- Departments of Internal Mediciane and Molecular Physiology and Biophysics and Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa; Iowa City Veterans Affairs Medical Center, Iowa City, Iowa; and
| | - Charles H Lang
- Department of Cellular and Molecular Physiology, Pennsylvania State College of Medicine, Hershey, Pennsylvania
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30
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Zeng H, Zhang JM, Du Y, Wang J, Ren Y, Li M, Li H, Cai Z, Chu Q, Yang C. Crosstalk between ATF4 and MTA1/HDAC1 promotes osteosarcoma progression. Oncotarget 2016; 7:7329-42. [PMID: 26797758 PMCID: PMC4872789 DOI: 10.18632/oncotarget.6940] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 01/01/2016] [Indexed: 02/01/2023] Open
Abstract
The stress response gene activating transcription factor 4 (ATF4) is involved in metastatic behavior and cellular protection. Here we show that ATF4 is upregulated in osteosarcoma (OS) cell lines and patient clinical samples as compared to matched non-tumor tissue. Overexpression of ATF4 in OS cells promoted cell proliferation, migration and lung metastasis. Furthermore, the expression of ATF4 was markedly reduced in metastasis associated protein (MTA1) or histone deacetylase 1 (HDAC1) knockdown OS cells, but MTA1 overexpression increased the stability and activity of ATF4 protein via ATF4 deacetylation by HDAC1. ATF4 in turn enhanced the expression of MTA1 and HDAC1 at the transcription level, suggesting a positive feedback loop between ATF4 and MTA1/HDAC1. Clinically, the level of ATF4 was positively correlated with that of MTA1 in OS. Mice injected with ATF4-overexpressing cells exhibited a higher rate of tumor growth, and the average weight of these tumors was ~90% greater than the controls. Taken together, these data establish a direct correlation between ATF4-induced OS progression and MTA1/HDAC1-associated metastasis, and support the potential therapeutic value of targeting ATF4 in the treatment of OS.
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Affiliation(s)
- Heng Zeng
- Department of Orthopedics, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
| | - Jin-ming Zhang
- Department of Orthopedics, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
| | - Yu Du
- Department of Orthopedics, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Chongqing Medical University, Chongqing 400016, P.R. China
| | - Jiang Wang
- Department of Orthopedics, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
| | - Ye Ren
- Department of Orthopedics, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
| | - Mi Li
- Department of Orthopedics, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
| | - Hao Li
- Department of Orthopedics, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
| | - Zhuo Cai
- Department of Orthopedics, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
| | - Qian Chu
- Department of Oncology, Tongji Hospital of Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
| | - Caihong Yang
- Department of Orthopedics, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
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Jin Y, Wang L, Qu S, Sheng X, Kristian A, Mælandsmo GM, Pällmann N, Yuca E, Tekedereli I, Gorgulu K, Alpay N, Sood A, Lopez-Berestein G, Fazli L, Rennie P, Risberg B, Wæhre H, Danielsen HE, Ozpolat B, Saatcioglu F. STAMP2 increases oxidative stress and is critical for prostate cancer. EMBO Mol Med 2015; 7:315-31. [PMID: 25680860 PMCID: PMC4364948 DOI: 10.15252/emmm.201404181] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The six transmembrane protein of prostate 2 (STAMP2) is an androgen-regulated gene whose mRNA expression is increased in prostate cancer (PCa). Here, we show that STAMP2 protein expression is increased in human PCa compared with benign prostate that is also correlated with tumor grade and treatment response. We also show that STAMP2 significantly increased reactive oxygen species (ROS) in PCa cells through its iron reductase activity which also depleted NADPH levels. Knockdown of STAMP2 expression in PCa cells inhibited proliferation, colony formation, and anchorage-independent growth, and significantly increased apoptosis. Furthermore, STAMP2 effects were, at least in part, mediated by activating transcription factor 4 (ATF4), whose expression is regulated by ROS. Consistent with in vitro findings, silencing STAMP2 significantly inhibited PCa xenograft growth in mice. Finally, therapeutic silencing of STAMP2 by systemically administered nanoliposomal siRNA profoundly inhibited tumor growth in two established preclinical PCa models in mice. These data suggest that STAMP2 is required for PCa progression and thus may serve as a novel therapeutic target.
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Affiliation(s)
- Yang Jin
- Department of Biosciences, University of Oslo, Oslo, Norway Institute for Cancer Genetics and Informatics, Oslo University Hospital, Oslo, Norway
| | - Ling Wang
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Su Qu
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Xia Sheng
- Department of Biosciences, University of Oslo, Oslo, Norway Institute for Cancer Genetics and Informatics, Oslo University Hospital, Oslo, Norway
| | | | | | - Nora Pällmann
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Erkan Yuca
- Department of Experimental Therapeutics, MD Anderson Cancer Center, Houston, TX, USA
| | - Ibrahim Tekedereli
- Department of Experimental Therapeutics, MD Anderson Cancer Center, Houston, TX, USA
| | - Kivanc Gorgulu
- Department of Experimental Therapeutics, MD Anderson Cancer Center, Houston, TX, USA
| | - Neslihan Alpay
- Department of Experimental Therapeutics, MD Anderson Cancer Center, Houston, TX, USA
| | - Anil Sood
- Gynecological Oncology, MD Anderson Cancer Center, Houston, TX, USA
| | | | - Ladan Fazli
- The Vancouver Prostate Centre, Vancouver, BC, Canada
| | - Paul Rennie
- The Vancouver Prostate Centre, Vancouver, BC, Canada
| | - Bjørn Risberg
- Institute for Cancer Genetics and Informatics, Oslo University Hospital, Oslo, Norway Division of Pathology, Oslo University Hospital, Oslo, Norway Division of Surgery, Oslo University Hospital, Oslo, Norway
| | - Håkon Wæhre
- Institute for Cancer Genetics and Informatics, Oslo University Hospital, Oslo, Norway Division of Pathology, Oslo University Hospital, Oslo, Norway Division of Surgery, Oslo University Hospital, Oslo, Norway Center for Cancer Biomedicine, University of Oslo, Oslo, Norway
| | - Håvard E Danielsen
- Institute for Cancer Genetics and Informatics, Oslo University Hospital, Oslo, Norway Center for Cancer Biomedicine, University of Oslo, Oslo, Norway Department of Informatics, University of Oslo, Oslo, Norway
| | - Bulent Ozpolat
- Department of Experimental Therapeutics, MD Anderson Cancer Center, Houston, TX, USA
| | - Fahri Saatcioglu
- Department of Biosciences, University of Oslo, Oslo, Norway Institute for Cancer Genetics and Informatics, Oslo University Hospital, Oslo, Norway
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Ahluwalia M, Butcher L, Donovan H, Killick-Cole C, Jones PM, Erusalimsky JD. The gene expression signature of anagrelide provides an insight into its mechanism of action and uncovers new regulators of megakaryopoiesis. J Thromb Haemost 2015; 13:1103-12. [PMID: 25851510 DOI: 10.1111/jth.12959] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 04/02/2015] [Indexed: 11/29/2022]
Abstract
BACKGROUND Anagrelide is a cytoreductive agent used to lower platelet counts in essential thrombocythemia. Although the drug has been known to selectively inhibit megakaryopoiesis for many years, the molecular mechanism accounting for this activity is still unclear. OBJECTIVES AND METHODS To address this issue we have compared the global gene expression profiles of human hematopoietic cells treated ex-vivo with and without anagrelide while growing under megakaryocyte differentiation conditions, using high-density oligonucleotide microarrays. Gene expression data were validated by the quantitative polymerase chain reaction and mined to identify functional subsets and regulatory pathways. RESULTS We identified 328 annotated genes differentially regulated by anagrelide, including many genes associated with platelet functions and with the control of gene transcription. Prominent among the latter was TRIB3, whose expression increased in the presence of anagrelide. Pathway analysis revealed that anagrelide up-regulated genes that are under the control of the transcription factor ATF4, a known TRIB3 inducer. Notably, immunoblot analysis demonstrated that anagrelide induced the phosphorylation of eIF2α, which is an upstream regulator of ATF4, and increased ATF4 protein levels. Furthermore, salubrinal, an inhibitor of eIF2α dephosphorylation, increased the expression of ATF4-regulated genes and blocked megakaryocyte growth. CONCLUSIONS These findings link signaling through eIF2α/ATF4 to the anti-megakaryopoietic activity of anagrelide and identify new potential modulators of megakaryopoiesis.
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Affiliation(s)
- M Ahluwalia
- School of Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - L Butcher
- School of Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - H Donovan
- School of Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - C Killick-Cole
- School of Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - P M Jones
- School of Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - J D Erusalimsky
- School of Health Sciences, Cardiff Metropolitan University, Cardiff, UK
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33
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Zhou AX, Wang X, Lin CS, Han J, Yong J, Nadolski MJ, Borén J, Kaufman RJ, Tabas I. C/EBP-Homologous Protein (CHOP) in Vascular Smooth Muscle Cells Regulates Their Proliferation in Aortic Explants and Atherosclerotic Lesions. Circ Res 2015; 116:1736-43. [PMID: 25872946 DOI: 10.1161/circresaha.116.305602] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Accepted: 04/13/2015] [Indexed: 01/27/2023]
Abstract
RATIONALE Myeloid-derived C/EBP-homologous protein (CHOP), an effector of the endoplasmic reticulum stress-induced unfolded protein response, promotes macrophage apoptosis in advanced atherosclerosis, but the role of CHOP in vascular smooth muscle cells (VSMCs) in atherosclerosis is not known. OBJECTIVE To investigate the role of CHOP in SM22α(+) VSMCs in atherosclerosis. METHODS AND RESULTS Chop(fl/fl) mice were generated and crossed into the Apoe(-/-) and SM22α-CreKI(+) backgrounds. SM22α-CreKI causes deletion of floxed genes in adult SMCs. After 12 weeks of Western-type diet feeding, the content of α-actin-positive cells in aortic root lesions was decreased in Chop(fl/fl)SM22α-CreKI(+)Apoe(-/-) versus control Chop(fl/fl)Apoe(-/-) mice, and aortic explant-derived VSMCs from the VSMC-CHOP-deficient mice displayed reduced proliferation. Krüppel-like factor 4 (KLF4), a key suppressor of VSMC proliferation, was increased in lesions and aortic VSMCs from Chop(fl/fl)SM22α-CreKI(+)Apoe(-/-) mice, and silencing Klf4 in CHOP-deficient VSMCs restored proliferation. CHOP deficiency in aortic VSMCs increased KLF4 through 2 mechanisms mediated by the endoplasmic reticulum stress effector activating transcription factor 4: transcriptional induction of Klf4 mRNA and decreased proteasomal degradation of KLF4 protein. CONCLUSIONS These findings in SM22α-CHOP-deficient mice imply that CHOP expression in SM22α(+) VSMCs promotes cell proliferation by downregulating KLF4. The mechanisms involve newly discovered roles of CHOP in the transcriptional and post-translational regulation of KLF4.
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Affiliation(s)
- Alex-Xianghua Zhou
- From the Departments of Medicine (A.-X.Z., X.W., M.J.N., I.T.), Pathology and Cell Biology (C.S.L., I.T.), and Physiology and Cellular Biophysics (I.T.), Columbia University, New York, NY; Department of Molecular and Clinical Medicine/Wallenberg Laboratory, University of Gothenburg and Sahlgrenska University Hospital, Gothenburg, Sweden (A.-X.Z., J.B.); CVMD iMed Translational Science, AstraZeneca R and D, Mölndal, Sweden (A.-X.Z.); Soonchunhyang Institute of Med-Bio Science, Soonchunhyang University, Cheon-an, South Korea (J.H.); and Degenerative Disease Program, Sanford-Burnham Medical Research Institute, La Jolla, CA (J.H., J.Y., R.J.K.)
| | - Xiaobo Wang
- From the Departments of Medicine (A.-X.Z., X.W., M.J.N., I.T.), Pathology and Cell Biology (C.S.L., I.T.), and Physiology and Cellular Biophysics (I.T.), Columbia University, New York, NY; Department of Molecular and Clinical Medicine/Wallenberg Laboratory, University of Gothenburg and Sahlgrenska University Hospital, Gothenburg, Sweden (A.-X.Z., J.B.); CVMD iMed Translational Science, AstraZeneca R and D, Mölndal, Sweden (A.-X.Z.); Soonchunhyang Institute of Med-Bio Science, Soonchunhyang University, Cheon-an, South Korea (J.H.); and Degenerative Disease Program, Sanford-Burnham Medical Research Institute, La Jolla, CA (J.H., J.Y., R.J.K.).
| | - Chyuan Sheng Lin
- From the Departments of Medicine (A.-X.Z., X.W., M.J.N., I.T.), Pathology and Cell Biology (C.S.L., I.T.), and Physiology and Cellular Biophysics (I.T.), Columbia University, New York, NY; Department of Molecular and Clinical Medicine/Wallenberg Laboratory, University of Gothenburg and Sahlgrenska University Hospital, Gothenburg, Sweden (A.-X.Z., J.B.); CVMD iMed Translational Science, AstraZeneca R and D, Mölndal, Sweden (A.-X.Z.); Soonchunhyang Institute of Med-Bio Science, Soonchunhyang University, Cheon-an, South Korea (J.H.); and Degenerative Disease Program, Sanford-Burnham Medical Research Institute, La Jolla, CA (J.H., J.Y., R.J.K.)
| | - Jaeseok Han
- From the Departments of Medicine (A.-X.Z., X.W., M.J.N., I.T.), Pathology and Cell Biology (C.S.L., I.T.), and Physiology and Cellular Biophysics (I.T.), Columbia University, New York, NY; Department of Molecular and Clinical Medicine/Wallenberg Laboratory, University of Gothenburg and Sahlgrenska University Hospital, Gothenburg, Sweden (A.-X.Z., J.B.); CVMD iMed Translational Science, AstraZeneca R and D, Mölndal, Sweden (A.-X.Z.); Soonchunhyang Institute of Med-Bio Science, Soonchunhyang University, Cheon-an, South Korea (J.H.); and Degenerative Disease Program, Sanford-Burnham Medical Research Institute, La Jolla, CA (J.H., J.Y., R.J.K.)
| | - Jing Yong
- From the Departments of Medicine (A.-X.Z., X.W., M.J.N., I.T.), Pathology and Cell Biology (C.S.L., I.T.), and Physiology and Cellular Biophysics (I.T.), Columbia University, New York, NY; Department of Molecular and Clinical Medicine/Wallenberg Laboratory, University of Gothenburg and Sahlgrenska University Hospital, Gothenburg, Sweden (A.-X.Z., J.B.); CVMD iMed Translational Science, AstraZeneca R and D, Mölndal, Sweden (A.-X.Z.); Soonchunhyang Institute of Med-Bio Science, Soonchunhyang University, Cheon-an, South Korea (J.H.); and Degenerative Disease Program, Sanford-Burnham Medical Research Institute, La Jolla, CA (J.H., J.Y., R.J.K.)
| | - Marissa J Nadolski
- From the Departments of Medicine (A.-X.Z., X.W., M.J.N., I.T.), Pathology and Cell Biology (C.S.L., I.T.), and Physiology and Cellular Biophysics (I.T.), Columbia University, New York, NY; Department of Molecular and Clinical Medicine/Wallenberg Laboratory, University of Gothenburg and Sahlgrenska University Hospital, Gothenburg, Sweden (A.-X.Z., J.B.); CVMD iMed Translational Science, AstraZeneca R and D, Mölndal, Sweden (A.-X.Z.); Soonchunhyang Institute of Med-Bio Science, Soonchunhyang University, Cheon-an, South Korea (J.H.); and Degenerative Disease Program, Sanford-Burnham Medical Research Institute, La Jolla, CA (J.H., J.Y., R.J.K.)
| | - Jan Borén
- From the Departments of Medicine (A.-X.Z., X.W., M.J.N., I.T.), Pathology and Cell Biology (C.S.L., I.T.), and Physiology and Cellular Biophysics (I.T.), Columbia University, New York, NY; Department of Molecular and Clinical Medicine/Wallenberg Laboratory, University of Gothenburg and Sahlgrenska University Hospital, Gothenburg, Sweden (A.-X.Z., J.B.); CVMD iMed Translational Science, AstraZeneca R and D, Mölndal, Sweden (A.-X.Z.); Soonchunhyang Institute of Med-Bio Science, Soonchunhyang University, Cheon-an, South Korea (J.H.); and Degenerative Disease Program, Sanford-Burnham Medical Research Institute, La Jolla, CA (J.H., J.Y., R.J.K.)
| | - Randal J Kaufman
- From the Departments of Medicine (A.-X.Z., X.W., M.J.N., I.T.), Pathology and Cell Biology (C.S.L., I.T.), and Physiology and Cellular Biophysics (I.T.), Columbia University, New York, NY; Department of Molecular and Clinical Medicine/Wallenberg Laboratory, University of Gothenburg and Sahlgrenska University Hospital, Gothenburg, Sweden (A.-X.Z., J.B.); CVMD iMed Translational Science, AstraZeneca R and D, Mölndal, Sweden (A.-X.Z.); Soonchunhyang Institute of Med-Bio Science, Soonchunhyang University, Cheon-an, South Korea (J.H.); and Degenerative Disease Program, Sanford-Burnham Medical Research Institute, La Jolla, CA (J.H., J.Y., R.J.K.)
| | - Ira Tabas
- From the Departments of Medicine (A.-X.Z., X.W., M.J.N., I.T.), Pathology and Cell Biology (C.S.L., I.T.), and Physiology and Cellular Biophysics (I.T.), Columbia University, New York, NY; Department of Molecular and Clinical Medicine/Wallenberg Laboratory, University of Gothenburg and Sahlgrenska University Hospital, Gothenburg, Sweden (A.-X.Z., J.B.); CVMD iMed Translational Science, AstraZeneca R and D, Mölndal, Sweden (A.-X.Z.); Soonchunhyang Institute of Med-Bio Science, Soonchunhyang University, Cheon-an, South Korea (J.H.); and Degenerative Disease Program, Sanford-Burnham Medical Research Institute, La Jolla, CA (J.H., J.Y., R.J.K.).
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Lees EK, Król E, Grant L, Shearer K, Wyse C, Moncur E, Bykowska AS, Mody N, Gettys TW, Delibegovic M. Methionine restriction restores a younger metabolic phenotype in adult mice with alterations in fibroblast growth factor 21. Aging Cell 2014; 13:817-27. [PMID: 24935677 PMCID: PMC4331744 DOI: 10.1111/acel.12238] [Citation(s) in RCA: 140] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/18/2014] [Indexed: 01/08/2023] Open
Abstract
Methionine restriction (MR) decreases body weight and adiposity and improves glucose homeostasis in rodents. Similar to caloric restriction, MR extends lifespan, but is accompanied by increased food intake and energy expenditure. Most studies have examined MR in young animals; therefore, the aim of this study was to investigate the ability of MR to reverse age-induced obesity and insulin resistance in adult animals. Male C57BL/6J mice aged 2 and 12 months old were fed MR (0.172% methionine) or control diet (0.86% methionine) for 8 weeks or 48 h. Food intake and whole-body physiology were assessed and serum/tissues analyzed biochemically. Methionine restriction in 12-month-old mice completely reversed age-induced alterations in body weight, adiposity, physical activity, and glucose tolerance to the levels measured in healthy 2-month-old control-fed mice. This was despite a significant increase in food intake in 12-month-old MR-fed mice. Methionine restriction decreased hepatic lipogenic gene expression and caused a remodeling of lipid metabolism in white adipose tissue, alongside increased insulin-induced phosphorylation of the insulin receptor (IR) and Akt in peripheral tissues. Mice restricted of methionine exhibited increased circulating and hepatic gene expression levels of FGF21, phosphorylation of eIF2a, and expression of ATF4, with a concomitant decrease in IRE1α phosphorylation. Short-term 48-h MR treatment increased hepatic FGF21 expression/secretion and insulin signaling and improved whole-body glucose homeostasis without affecting body weight. Our findings suggest that MR feeding can reverse the negative effects of aging on body mass, adiposity, and insulin resistance through an FGF21 mechanism. These findings implicate MR dietary intervention as a viable therapy for age-induced metabolic syndrome in adult humans.
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Affiliation(s)
- Emma K. Lees
- Institute of Medical Sciences; College of Life Sciences and Medicine; University of Aberdeen; Aberdeen AB25 2ZD UK
| | - Elżbieta Król
- Institute of Biological and Environmental Sciences; University of Aberdeen; Aberdeen AB24 2TZ UK
| | - Louise Grant
- Institute of Medical Sciences; College of Life Sciences and Medicine; University of Aberdeen; Aberdeen AB25 2ZD UK
| | - Kirsty Shearer
- Institute of Medical Sciences; College of Life Sciences and Medicine; University of Aberdeen; Aberdeen AB25 2ZD UK
| | - Cathy Wyse
- Institute of Biological and Environmental Sciences; University of Aberdeen; Aberdeen AB24 2TZ UK
| | - Eleanor Moncur
- Institute of Medical Sciences; College of Life Sciences and Medicine; University of Aberdeen; Aberdeen AB25 2ZD UK
| | - Aleksandra S. Bykowska
- Institute of Medical Sciences; College of Life Sciences and Medicine; University of Aberdeen; Aberdeen AB25 2ZD UK
| | - Nimesh Mody
- Institute of Medical Sciences; College of Life Sciences and Medicine; University of Aberdeen; Aberdeen AB25 2ZD UK
| | - Thomas W. Gettys
- Nutrient Sensing and Adipocyte Signaling Department; Pennington Biomedical Research Center; Baton Rouge LA 70808 USA
| | - Mirela Delibegovic
- Institute of Medical Sciences; College of Life Sciences and Medicine; University of Aberdeen; Aberdeen AB25 2ZD UK
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Fox DK, Ebert SM, Bongers KS, Dyle MC, Bullard SA, Dierdorff JM, Kunkel SD, Adams CM. p53 and ATF4 mediate distinct and additive pathways to skeletal muscle atrophy during limb immobilization. Am J Physiol Endocrinol Metab 2014; 307:E245-61. [PMID: 24895282 PMCID: PMC4121573 DOI: 10.1152/ajpendo.00010.2014] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Immobilization causes skeletal muscle atrophy via complex signaling pathways that are not well understood. To better understand these pathways, we investigated the roles of p53 and ATF4, two transcription factors that mediate adaptations to a variety of cellular stresses. Using mouse models, we demonstrate that 3 days of muscle immobilization induces muscle atrophy and increases expression of p53 and ATF4. Furthermore, muscle fibers lacking p53 or ATF4 are partially resistant to immobilization-induced muscle atrophy, and forced expression of p53 or ATF4 induces muscle fiber atrophy in the absence of immobilization. Importantly, however, p53 and ATF4 do not require each other to promote atrophy, and coexpression of p53 and ATF4 induces more atrophy than either transcription factor alone. Moreover, muscle fibers lacking both p53 and ATF4 are more resistant to immobilization-induced atrophy than fibers lacking only p53 or ATF4. Interestingly, the independent and additive nature of the p53 and ATF4 pathways allows for combinatorial control of at least one downstream effector, p21. Using genome-wide mRNA expression arrays, we identified p21 mRNA as a skeletal muscle transcript that is highly induced in immobilized muscle via the combined actions of p53 and ATF4. Additionally, in mouse muscle, p21 induces atrophy in a manner that does not require immobilization, p53 or ATF4, and p21 is required for atrophy induced by immobilization, p53, and ATF4. Collectively, these results identify p53 and ATF4 as essential and complementary mediators of immobilization-induced muscle atrophy and discover p21 as a critical downstream effector of the p53 and ATF4 pathways.
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Affiliation(s)
- Daniel K Fox
- Departments of Internal Medicine and Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; and
| | - Scott M Ebert
- Departments of Internal Medicine and Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; and
| | - Kale S Bongers
- Departments of Internal Medicine and Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; and
| | - Michael C Dyle
- Departments of Internal Medicine and Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; and
| | - Steven A Bullard
- Departments of Internal Medicine and Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; and Iowa City Veterans Affairs Medical Center, Iowa City, Iowa
| | - Jason M Dierdorff
- Departments of Internal Medicine and Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; and
| | - Steven D Kunkel
- Departments of Internal Medicine and Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; and
| | - Christopher M Adams
- Departments of Internal Medicine and Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; and Iowa City Veterans Affairs Medical Center, Iowa City, Iowa
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Abstract
MicroRNAs are small noncoding RNAs which regulate protein expression post-transcriptionally. They respond to changes in a cells environment and can promote cell death or cell survival depending on the context. Recent studies have linked microRNAs to the unfolded protein response pathway. This pathway is activated in the endoplasmic reticulum by conditions which interfere with the normal function of the endoplasmic reticulum. The cell fate outcomes consequent to the activation of the unfolded protein response are binary, either cell survival or cell death. MicroRNAs can regulate multiple components of this pathway to tip the cell towards either fate. Interestingly, inositol requiring enzyme 1 alpha, a canonical unfolded protein response sensor and mediator, has inherent endoribonuclease activity. Recently, it has been demonstrated that it can target microRNAs in addition to its previously known targets. This review highlights key papers in this rapidly emerging field.
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Nakamura MT, Yudell BE, Loor JJ. Regulation of energy metabolism by long-chain fatty acids. Prog Lipid Res 2013; 53:124-44. [PMID: 24362249 DOI: 10.1016/j.plipres.2013.12.001] [Citation(s) in RCA: 467] [Impact Index Per Article: 42.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 12/03/2013] [Accepted: 12/04/2013] [Indexed: 12/12/2022]
Abstract
In mammals, excess energy is stored primarily as triglycerides, which are mobilized when energy demands arise. This review mainly focuses on the role of long chain fatty acids (LCFAs) in regulating energy metabolism as ligands of peroxisome proliferator-activated receptors (PPARs). PPAR-alpha expressed primarily in liver is essential for metabolic adaptation to starvation by inducing genes for beta-oxidation and ketogenesis and by downregulating energy expenditure through fibroblast growth factor 21. PPAR-delta is highly expressed in skeletal muscle and induces genes for LCFA oxidation during fasting and endurance exercise. PPAR-delta also regulates glucose metabolism and mitochondrial biogenesis by inducing FOXO1 and PGC1-alpha. Genes targeted by PPAR-gamma in adipocytes suggest that PPAR-gamma senses incoming non-esterified LCFAs and induces the pathways to store LCFAs as triglycerides. Adiponectin, another important target of PPAR-gamma may act as a spacer between adipocytes to maintain their metabolic activity and insulin sensitivity. Another topic of this review is effects of skin LCFAs on energy metabolism. Specific LCFAs are required for the synthesis of skin lipids, which are essential for water barrier and thermal insulation functions of the skin. Disturbance of skin lipid metabolism often causes apparent resistance to developing obesity at the expense of normal skin function.
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Affiliation(s)
- Manabu T Nakamura
- Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, 905 South Goodwin Avenue, Urbana, IL 61801, USA.
| | - Barbara E Yudell
- Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, 905 South Goodwin Avenue, Urbana, IL 61801, USA
| | - Juan J Loor
- Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, 905 South Goodwin Avenue, Urbana, IL 61801, USA
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Caldeira MV, Salazar IL, Curcio M, Canzoniero LMT, Duarte CB. Role of the ubiquitin-proteasome system in brain ischemia: friend or foe? Prog Neurobiol 2013; 112:50-69. [PMID: 24157661 DOI: 10.1016/j.pneurobio.2013.10.003] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 10/08/2013] [Accepted: 10/15/2013] [Indexed: 11/26/2022]
Abstract
The ubiquitin-proteasome system (UPS) is a catalytic machinery that targets numerous cellular proteins for degradation, thus being essential to control a wide range of basic cellular processes and cell survival. Degradation of intracellular proteins via the UPS is a tightly regulated process initiated by tagging a target protein with a specific ubiquitin chain. Neurons are particularly vulnerable to any change in protein composition, and therefore the UPS is a key regulator of neuronal physiology. Alterations in UPS activity may induce pathological responses, ultimately leading to neuronal cell death. Brain ischemia triggers a complex series of biochemical and molecular mechanisms, such as an inflammatory response, an exacerbated production of misfolded and oxidized proteins, due to oxidative stress, and the breakdown of cellular integrity mainly mediated by excitotoxic glutamatergic signaling. Brain ischemia also damages protein degradation pathways which, together with the overproduction of damaged proteins and consequent upregulation of ubiquitin-conjugated proteins, contribute to the accumulation of ubiquitin-containing proteinaceous deposits. Despite recent advances, the factors leading to deposition of such aggregates after cerebral ischemic injury remain poorly understood. This review discusses the current knowledge on the role of the UPS in brain function and the molecular mechanisms contributing to UPS dysfunction in brain ischemia with consequent accumulation of ubiquitin-containing proteins. Chemical inhibitors of the proteasome and small molecule inhibitors of deubiquitinating enzymes, which promote the degradation of proteins by the proteasome, were both shown to provide neuroprotection in brain ischemia, and this apparent contradiction is also discussed in this review.
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Affiliation(s)
- Margarida V Caldeira
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal; Department of Life Sciences, University of Coimbra, 3004-517 Coimbra, Portugal
| | - Ivan L Salazar
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal; Doctoral Programme in Experimental Biology and Biomedicine, Center for Neuroscience and Cell Biology, University of Coimbra, Portugal; Institute for Interdisciplinary Research, University of Coimbra (IIIUC), Portugal
| | - Michele Curcio
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal; Department of Science and Technology, University of Sannio, Benevento, Italy
| | | | - Carlos B Duarte
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal; Department of Life Sciences, University of Coimbra, 3004-517 Coimbra, Portugal.
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Komoike Y, Matsuoka M. Exposure to tributyltin induces endoplasmic reticulum stress and the unfolded protein response in zebrafish. Aquat Toxicol 2013; 142-143:221-229. [PMID: 24055755 DOI: 10.1016/j.aquatox.2013.08.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 08/22/2013] [Accepted: 08/27/2013] [Indexed: 06/02/2023]
Abstract
Tributyltin (TBT) is a major marine contaminant and causes endocrine disruption, hepatotoxicity, immunotoxicity, and neurotoxicity. However, the molecular mechanisms underlying the toxicity of TBT have not been fully elucidated. We examined whether exposure to TBT induces the endoplasmic reticulum (ER) stress response in zebrafish, a model organism. Zebrafish-derived BRF41 fibroblast cells were exposed to 0.5 or 1 μM TBT for 0.5-16 h and subsequently lysed and immunoblotted to detect ER stress-related proteins. Zebrafish embryos, grown until 32 h post fertilization (hpf), were exposed to 1 μM TBT for 16 h and used in whole mount in situ hybridization and immunohistochemistry to visualize the expression of ER chaperones and an ER stress-related apoptosis factor. Exposure of the BRF41 cells to TBT caused phosphorylation of the zebrafish homolog of protein kinase RNA-activated-like ER kinase (PERK), eukaryotic translation initiation factor 2 alpha (eIF2α), and inositol-requiring enzyme 1 (IRE1), characteristic splicing of X-box binding protein 1 (XBP1) mRNA, and enhanced expression of activating transcription factor 4 (ATF4) protein. In TBT-exposed zebrafish embryos, ectopic expression of the gene encoding zebrafish homolog of the 78 kDa glucose-regulating protein (GRP78) and gene encoding CCAAT/enhancer-binding protein homologous protein (CHOP) was detected in the precursors of the neuromast, which is a sensory organ for detecting water flow and vibration. Our in vitro and in vivo studies revealed that exposure of zebrafish to TBT induces the ER stress response via activation of both the PERK-eIF2α and IRE1-XBP1 pathways of the unfolded protein response (UPR) in an organ-specific manner.
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Affiliation(s)
- Yuta Komoike
- Department of Hygiene and Public Health I, School of Medicine, Tokyo Women's Medical University, 8-1 Kawadacho, Shinjuku, Tokyo 162-8666, Japan.
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Bongers KS, Fox DK, Ebert SM, Kunkel SD, Dyle MC, Bullard SA, Dierdorff JM, Adams CM. Skeletal muscle denervation causes skeletal muscle atrophy through a pathway that involves both Gadd45a and HDAC4. Am J Physiol Endocrinol Metab 2013; 305:E907-15. [PMID: 23941879 PMCID: PMC3798708 DOI: 10.1152/ajpendo.00380.2013] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Skeletal muscle denervation causes muscle atrophy via complex molecular mechanisms that are not well understood. To better understand these mechanisms, we investigated how muscle denervation increases growth arrest and DNA damage-inducible 45α (Gadd45a) mRNA in skeletal muscle. Previous studies established that muscle denervation strongly induces Gadd45a mRNA, which increases Gadd45a, a small myonuclear protein that is required for denervation-induced muscle fiber atrophy. However, the mechanism by which denervation increases Gadd45a mRNA remained unknown. Here, we demonstrate that histone deacetylase 4 (HDAC4) mediates induction of Gadd45a mRNA in denervated muscle. Using mouse models, we show that HDAC4 is required for induction of Gadd45a mRNA during muscle denervation. Conversely, forced expression of HDAC4 is sufficient to increase skeletal muscle Gadd45a mRNA in the absence of muscle denervation. Moreover, Gadd45a mediates several downstream effects of HDAC4, including induction of myogenin mRNA, induction of mRNAs encoding the embryonic nicotinic acetylcholine receptor, and, most importantly, skeletal muscle fiber atrophy. Because Gadd45a induction is also a key event in fasting-induced muscle atrophy, we tested whether HDAC4 might also contribute to Gadd45a induction during fasting. Interestingly, however, HDAC4 is not required for fasting-induced Gadd45a expression or muscle atrophy. Furthermore, activating transcription factor 4 (ATF4), which contributes to fasting-induced Gadd45a expression, is not required for denervation-induced Gadd45a expression or muscle atrophy. Collectively, these results identify HDAC4 as an important regulator of Gadd45a in denervation-induced muscle atrophy and elucidate Gadd45a as a convergence point for distinct upstream regulators during muscle denervation and fasting.
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Affiliation(s)
- Kale S Bongers
- Departments of Internal Medicine and Molecular Physiology and Biophysics and Fraternal Order of Eagles Diabetes Research Center, Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, Iowa; and
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Apostolova N, Gomez-Sucerquia LJ, Alegre F, Funes HA, Victor VM, Barrachina MD, Blas-Garcia A, Esplugues JV. ER stress in human hepatic cells treated with Efavirenz: mitochondria again. J Hepatol 2013; 59:780-9. [PMID: 23792026 DOI: 10.1016/j.jhep.2013.06.005] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 05/23/2013] [Accepted: 06/10/2013] [Indexed: 12/04/2022]
Abstract
BACKGROUND & AIMS ER stress is associated with a growing number of liver diseases, including drug-induced hepatotoxicity. The non-nucleoside analogue reverse transcriptase inhibitor Efavirenz, a cornerstone of the multidrug strategy employed to treat HIV1 infection, has been related to the development of various adverse events, including metabolic disturbances and hepatic toxicity, the mechanisms of which remain elusive. Recent evidence has pinpointed a specific mitochondrial effect of Efavirenz in human hepatic cells. This study assesses the induction of ER stress by Efavirenz in the same model and the implication of mitochondria in this process. METHODS Primary human hepatocytes and Hep3B were treated with clinically relevant concentrations of Efavirenz and parameters of ER stress were studied using standard cell biology techniques. RESULTS ER stress markers, including CHOP and GRP78 expression (both protein and mRNA), phosphorylation of eIF2α, and presence of the spliced form of XBP1 were upregulated. Efavirenz also enhanced cytosolic Ca(2+) content and induced morphological changes in the ER suggestive of ER stress. This response was greatly attenuated in cells with altered mitochondrial function (Rho°). The effects of Efavirenz on the ER, and particularly in regard to the mitochondrial involvement, differed from those elicited by a standard pharmacological ER stressor. CONCLUSIONS This newly discovered mechanism of cellular insult involving ER stress and UPR response may help comprehend the hepatic toxicity that has been associated with the widespread and life-long use of Efavirenz. In addition, the specificity of the actions of Efavirenz observed expands our knowledge of the mechanisms that trigger ER stress and shed some light on the mitochondria/ER interplay in drug-induced hepatic challenge.
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Dennis MD, McGhee NK, Jefferson LS, Kimball SR. Regulated in DNA damage and development 1 (REDD1) promotes cell survival during serum deprivation by sustaining repression of signaling through the mechanistic target of rapamycin in complex 1 (mTORC1). Cell Signal 2013; 25:2709-16. [PMID: 24018049 DOI: 10.1016/j.cellsig.2013.08.038] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 08/30/2013] [Indexed: 12/25/2022]
Abstract
Regulated in DNA damage and development 1 (REDD1) functions to repress signaling through the mechanistic target of rapamycin (mTOR) protein kinase in complex 1 (mTORC1) in response to diverse stress conditions. In the present study, we investigated the role of REDD1 in the response of cells to growth cessation induced by serum deprivation. REDD1 expression was induced within 2h of depriving cells of serum, with the induction being mediated through ER stress, as evidenced by activation of PERK, enhanced eIF2α phosphorylation, and ATF4 facilitated transcription of the REDD1 gene. In wild-type cells, signaling through mTORC1 was rapidly (within 30min) repressed in response to serum deprivation and the repression was sustained for at least 10h. In contrast, in REDD1 knockout cells mTORC1 signaling recovered toward the end of the 10h-deprivation period. Interestingly, Akt phosphorylation initially declined in response to serum deprivation and then recovered between 2 and 4h in wild-type but not REDD1 knockout cells. The recovery of mTORC1 signaling and the failure of Akt phosphorylation to do so in the REDD1 knockout cells were accompanied by a dramatic increase in caspase-3 cleavage and cell death, both of which were blocked by rapamycin. Furthermore, overexpression of constitutively active Akt rescued REDD1 knockout cells from serum deprivation induced cell death. Overall, the results implicate REDD1 as a key regulatory checkpoint that coordinates growth signaling inputs to activate pro-survival mechanisms and reduce susceptibility to cell death.
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Wang X, Wang G, Kunte M, Shinde V, Gorbatyuk M. Modulation of angiogenesis by genetic manipulation of ATF4 in mouse model of oxygen-induced retinopathy [corrected]. Invest Ophthalmol Vis Sci 2013; 54:5995-6002. [PMID: 23942974 DOI: 10.1167/iovs.13-12117] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The activation of the unfolded protein response (UPR) and an increase in activating transcription factor 4 (ATF4) has been previously reported in the diabetic retina. Despite this, a direct link between ATF4 and the degree of proliferative retinopathy has not been demonstrated to date. Therefore, the objective of this study was to determine whether ATF4 deficiency could reduce neovascularization in mice with oxygen-induced retinopathy (OIR). METHODS We induced OIR in C57BL/6, ATF4(+/-), and endoplasmic reticulum stress-activated indicator (ERAI) mice and used quantitative RT-PCR and Western blot analysis to evaluate relative gene and protein expression. Histology and microscopy were used to calculate the extent of neovascularization in flat-mounted retinas. RESULTS Experimental data revealed Xbp1 splicing in the retinal ganglia cells, outer plexiform layer, inner nuclear layer, and outer nuclear layer and in pericytes of postdevelopment day 17 ERAI OIR mice, confirming the activation of IRE1 UPR signaling. In naive ATF4-deficient mice, we also observed an elevation in UPR-associated and vascular-associated gene expression (Bip, Atf6, Hif1a, Pik3/Akt, Flt1/Vegfa, and Tgfb1), which may have contributed to the alleviation of hypoxia-driven neovascularization in experimental ATF4(+/-) retinas. The OIR ATF4(+/-) retinas demonstrated reprogramming of the UPR seen at both the mRNA (Atf6 and Bip) and protein (pATF6 and peIf2α) levels, as well as a reduction in vascularization-associated gene expression (Flt1, Vegf1, Hif1, and Tgb1). These changes corresponded to the decline in the rate of neovascularization. CONCLUSIONS Our study validates ATF4 as a prospective therapeutic target to inhibit neovascularization in proliferative retinopathy.
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Affiliation(s)
- Xiaoqin Wang
- Department of Cell Biology and Anatomy, University of North Texas Health Science Center, North Texas Eye Research Institute, Fort Worth, Texas, USA
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Shan J, Hamazaki T, Tang TA, Terada N, Kilberg MS. Activation of the amino acid response modulates lineage specification during differentiation of murine embryonic stem cells. Am J Physiol Endocrinol Metab 2013; 305:E325-35. [PMID: 23736538 PMCID: PMC4116408 DOI: 10.1152/ajpendo.00136.2013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In somatic cells, a collection of signaling pathways activated by amino acid limitation have been identified and referred to as the amino acid response (AAR). Despite the importance of possible detrimental effects of nutrient limitation during in vitro culture, the AAR has not been investigated in embryonic stem cells (ESC). AAR activation caused the expected increase in transcription factors that mediate specific AAR pathways, as well as the induction of asparagine synthetase, a terminal AAR target gene. Neither AAR activation nor stable knockdown of activating transcription factor (Atf) 4, a transcriptional mediator of the AAR, adversely affected ESC self-renewal or pluripotency. Low-level induction of the AAR over a 12-day period of embryoid body differentiation did alter lineage specification such that the primitive endodermal, visceral endodermal, and endodermal lineages were favored, whereas mesodermal and certain ectodermal lineages were suppressed. Knockdown of Atf4 further enhanced the AAR-induced increase in endodermal formation, suggesting that this phenomenon is mediated by an Atf4-independent mechanism. Collectively, the results indicate that, during differentiation of mouse embryoid bodies in culture, the availability of nutrients, such as amino acids, can influence the formation of specific cell lineages.
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Affiliation(s)
- Jixiu Shan
- Department of Biochemistry and Molecular Biology, McKnight Brain Institute, Shands Cancer Center, and Center for Nutritional Sciences, University of Florida College of Medicine, Gainesville, Florida, USA
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Sano R, Reed JC. ER stress-induced cell death mechanisms. Biochim Biophys Acta 2013; 1833:3460-3470. [PMID: 23850759 DOI: 10.1016/j.bbamcr.2013.06.028] [Citation(s) in RCA: 1390] [Impact Index Per Article: 126.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 06/24/2013] [Accepted: 06/26/2013] [Indexed: 02/07/2023]
Abstract
The endoplasmic-reticulum (ER) stress response constitutes a cellular process that is triggered by a variety of conditions that disturb folding of proteins in the ER. Eukaryotic cells have developed an evolutionarily conserved adaptive mechanism, the unfolded protein response (UPR), which aims to clear unfolded proteins and restore ER homeostasis. In cases where ER stress cannot be reversed, cellular functions deteriorate, often leading to cell death. Accumulating evidence implicates ER stress-induced cellular dysfunction and cell death as major contributors to many diseases, making modulators of ER stress pathways potentially attractive targets for therapeutics discovery. Here, we summarize recent advances in understanding the diversity of molecular mechanisms that govern ER stress signaling in health and disease. This article is part of a Special Section entitled: Cell Death Pathways.
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Affiliation(s)
- Renata Sano
- Sanford-Burnham Medical Research Institute, La Jolla, CA, 92037, USA
| | - John C Reed
- Sanford-Burnham Medical Research Institute, La Jolla, CA, 92037, USA.
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Salazar M, Lorente M, García-Taboada E, Hernández-Tiedra S, Davila D, Francis SE, Guzmán M, Kiss-Toth E, Velasco G. The pseudokinase tribbles homologue-3 plays a crucial role in cannabinoid anticancer action. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:1573-8. [PMID: 23567453 DOI: 10.1016/j.bbalip.2013.03.014] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 03/27/2013] [Indexed: 01/16/2023]
Abstract
Δ(9)-Tetrahydrocannabinol (THC), the major active ingredient of marijuana, and other cannabinoids inhibit tumor growth in animal models of cancer. This effect relies, at least in part, on the up-regulation of several endoplasmic reticulum stress-related proteins including the pseudokinase tribbles homologue-3 (TRIB3), which leads in turn to the inhibition of the AKT/mTORC1 axis and the subsequent stimulation of autophagy-mediated apoptosis in tumor cells. Here, we took advantage of the use of cells derived from Trib3-deficient mice to investigate the precise mechanisms by which TRIB3 regulates the anti-cancer action of THC. Our data show that RasV(12)/E1A-transformed embryonic fibroblasts derived from Trib3-deficient mice are resistant to THC-induced cell death. We also show that genetic inactivation of this protein abolishes the ability of THC to inhibit the phosphorylation of AKT and several of its downstream targets, including those involved in the regulation of the AKT/mammalian target of rapamycin complex 1 (mTORC1) axis. Our data support the idea that THC-induced TRIB3 up-regulation inhibits AKT phosphorylation by regulating the accessibility of AKT to its upstream activatory kinase (the mammalian target of rapamycin complex 2; mTORC2). Finally, we found that tumors generated by inoculation of Trib3-deficient cells in nude mice are resistant to THC anticancer action. Altogether, the observations presented here strongly support that TRIB3 plays a crucial role on THC anti-neoplastic activity. This article is part of a Special Issue entitled Lipid Metabolism in Cancer.
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Chen Y, Wang J, Li J, Hosoya K, Ratan R, Townes T, Zhang S. Activating transcription factor 4 mediates hyperglycaemia-induced endothelial inflammation and retinal vascular leakage through activation of STAT3 in a mouse model of type 1 diabetes. Diabetologia 2012; 55:2533-45. [PMID: 22660795 PMCID: PMC3412945 DOI: 10.1007/s00125-012-2594-1] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Accepted: 04/25/2012] [Indexed: 10/28/2022]
Abstract
AIMS/HYPOTHESIS There is convincing evidence that endoplasmic reticulum (ER) stress is implicated in the pathogenesis of diabetes and its complications; however, the mechanisms are not fully understood. This study aimed to dissect the role and signalling pathways of activating transcription factor 4 (ATF4) in ER-stress-associated endothelial inflammation and diabetic retinopathy. METHODS ER stress and ATF4 activity were manipulated by complementary pharmacological and genetic approaches in cultured retinal endothelial (TR-iBRB) cells. Diabetes was induced by streptozotocin in heterozygous Atf4 knockout and wild-type mice. ER stress markers, inflammatory cytokines and adhesion molecules, activation of the signal transducer and activator of transcription 3 (STAT3) pathway, and retinal vascular permeability were measured. RESULTS High-glucose treatment resulted in rapid induction of ER stress, activation of ATF4, and increased production of inflammatory factors in TR-iBRB cells. Suppressing ER stress or inhibiting ATF4 activity markedly attenuated high-glucose-induced production of intercellular adhesion molecule 1, TNF-α and vascular endothelial growth factor. Conversely, enhancing ER stress or overexpressing Atf4 was sufficient to induce endothelial inflammation, which was, at least in part, through activation of the STAT3 pathway. Furthermore, knockdown of the Stat3 gene or inhibiting STAT3 activity restored ER homeostasis in cells exposed to high glucose and prevented ATF4 activation, suggesting that STAT3 is required for high-glucose-induced ER stress. Finally, we showed that downregulation of Atf4 significantly ameliorated retinal inflammation, STAT3 activation and vascular leakage in a mouse model of type 1 diabetes. CONCLUSIONS/INTERPRETATION Taken together, our data reveal a pivotal role of ER stress and the ATF4/STAT3 pathway in retinal endothelial inflammation in diabetic retinopathy.
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Affiliation(s)
- Y. Chen
- Department of Medicine, Endocrinology and Diabetes, University of Oklahoma Health Sciences Center, 941 Stanton L Young Blvd, Oklahoma City, OK 73104, USA
- Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Department of Medicine, Endocrinology, the Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - J.J. Wang
- Department of Medicine, Endocrinology and Diabetes, University of Oklahoma Health Sciences Center, 941 Stanton L Young Blvd, Oklahoma City, OK 73104, USA
- Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - J. Li
- Department of Medicine, Endocrinology and Diabetes, University of Oklahoma Health Sciences Center, 941 Stanton L Young Blvd, Oklahoma City, OK 73104, USA
- Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - K.I. Hosoya
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - R. Ratan
- Department of Neurology and Neuroscience, Weill Medical College of Cornell University, The Burke Medical Research Institute, White Plains, NY, USA
| | - T. Townes
- Department of Biochemistry & Molecular Genetics, the University of Alabama at Birmingham, Birmingham, AL, USA
| | - S.X. Zhang
- Department of Medicine, Endocrinology and Diabetes, University of Oklahoma Health Sciences Center, 941 Stanton L Young Blvd, Oklahoma City, OK 73104, USA
- Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
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