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Hu Y, He T, Zhu J, Wang X, Tong J, Li Z, Dong J. The Link between Circadian Clock Genes and Autophagy in Chronic Obstructive Pulmonary Disease. Mediators Inflamm 2021; 2021:2689600. [PMID: 34733115 PMCID: PMC8560276 DOI: 10.1155/2021/2689600] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 10/08/2021] [Indexed: 11/29/2022] Open
Abstract
Chronic obstructive pulmonary disease (COPD), a progressive respiratory disease, is characterized by the alveolar epithelium injury and persistent airway inflammation. It is documented that oscillation and dysregulated expression of circadian clock genes, like Bmal1, Per1, and Per2, involved in COPD pathogenies, including chronic inflammation and imbalanced autophagy level, and targeting the associations of circadian rhythm and autophagy is promising strategies in the management and treatment of COPD. Herein, we reviewed the mechanisms of the circadian clock and the unbalance of the autophagic level in COPD, as well as the link between the two, so as to provide further theoretical bases for the study on the pathogenesis of COPD.
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Affiliation(s)
- Yuedi Hu
- College of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, No. 1, Qianjiang Road, Hefei City, Anhui Province, China
| | - Tiantian He
- College of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, No. 1, Qianjiang Road, Hefei City, Anhui Province, China
| | - Jie Zhu
- College of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, No. 1, Qianjiang Road, Hefei City, Anhui Province, China
- Institutes of Integrative Medicine, Fudan University, Shanghai, China
- Institute of Traditional Chinese Medicine Prevention and Control on Respiratory Disease, Anhui Academy of Chinese Medicine, No. 117, Meishan Road, Hefei City, Anhui Province, China
| | - Xiaole Wang
- Institute of Traditional Chinese Medicine Prevention and Control on Respiratory Disease, Anhui Academy of Chinese Medicine, No. 117, Meishan Road, Hefei City, Anhui Province, China
| | - Jiabing Tong
- Institute of Traditional Chinese Medicine Prevention and Control on Respiratory Disease, Anhui Academy of Chinese Medicine, No. 117, Meishan Road, Hefei City, Anhui Province, China
- Department of Respiratory Medicine, First Affiliated Hospital of Anhui University of Traditional Chinese Medicine, Meishan Road, Hefei City, Anhui Province, China
| | - Zegeng Li
- Institute of Traditional Chinese Medicine Prevention and Control on Respiratory Disease, Anhui Academy of Chinese Medicine, No. 117, Meishan Road, Hefei City, Anhui Province, China
- Department of Respiratory Medicine, First Affiliated Hospital of Anhui University of Traditional Chinese Medicine, Meishan Road, Hefei City, Anhui Province, China
| | - Jingcheng Dong
- Institutes of Integrative Medicine, Fudan University, Shanghai, China
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2
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Yoo J, Jeong IK, Ahn KJ, Chung HY, Hwang YC. Fenofibrate, a PPARα agonist, reduces hepatic fat accumulation through the upregulation of TFEB-mediated lipophagy. Metabolism 2021; 120:154798. [PMID: 33984335 DOI: 10.1016/j.metabol.2021.154798] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 04/18/2021] [Accepted: 05/09/2021] [Indexed: 01/27/2023]
Abstract
BACKGROUND Recent studies have shown that dysregulation of autophagy is involved in the development of nonalcoholic fatty liver disease (NAFLD). Transcription factors E3 (TFE3) and EB (TFEB) are master regulators of the transcriptional response of basic cellular processes such as lysosomal biogenesis and autophagy. Here, we investigated the role of fenofibrate, a PPARα agonist, in promotion of intracellular lipid clearance by upregulation of TFEB/TFE3. METHODS We investigated whether the effects of fenofibrate on livers were dependent on TFEB in high fat diet (HFD)-fed mice and in vivo Tfeb knockdown mice. These mice were analyzed for characteristics of obesity and diabetes; the effects of fenofibrate on hepatic fat content, glucose sensitivity, insulin resistance, and autophagy functional dependence on TFEB were investigated. HepG2, Hep3B, TSC2+/+ and tsc2-/- MEFs, tfeb wild type- and tfeb knockout-HeLa cells were used for in vitro experiments. RESULTS Fenofibrate treatment activated autophagy and TFEB/TFE3 and reduced hepatic fat accumulation in an mTOR-independent manner. Knockdown of TFEB offset the effects of fenofibrate on autophagy and hepatic fat accumulation. In addition, fenofibrate treatment induced lysosomal Ca2+ release through mucolipin 1, activated calcineurin and the CaMKKβ-AMPK-ULK1 pathway, subsequently promoted TFEB and TFE3 dephosphorylation and nuclear translocation. Treatment with calcium chelator or knockdown of mucolipin 1 in hepatocytes offset the effects of fenofibrate treatment on autophagy and hepatic fat accumulation. CONCLUSION Activation of PPARα ameliorates hepatic fat accumulation via activation of TFEB and lipophagy induction. Lysosomal calcium signaling appears to play a critical role in this process. In addition, activation of TFEB by modulating nuclear receptors including PPARα with currently available drugs or new molecules might be a therapeutic target for treatment of NAFLD and other cardiometabolic diseases.
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Affiliation(s)
- Jin Yoo
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul, Republic of Korea; Department of Endocrinology and Metabolism, Kyung Hee University Hospital at Gangdong, Seoul, Republic of Korea
| | - In-Kyung Jeong
- Department of Endocrinology and Metabolism, Kyung Hee University Hospital at Gangdong, Seoul, Republic of Korea; Division of Endocrinology and Metabolism, Department of Internal Medicine, Kyung Hee University School of Medicine, Seoul, Republic of Korea
| | - Kyu Jeung Ahn
- Department of Endocrinology and Metabolism, Kyung Hee University Hospital at Gangdong, Seoul, Republic of Korea; Division of Endocrinology and Metabolism, Department of Internal Medicine, Kyung Hee University School of Medicine, Seoul, Republic of Korea
| | - Ho Yeon Chung
- Department of Endocrinology and Metabolism, Kyung Hee University Hospital at Gangdong, Seoul, Republic of Korea; Division of Endocrinology and Metabolism, Department of Internal Medicine, Kyung Hee University School of Medicine, Seoul, Republic of Korea
| | - You-Cheol Hwang
- Department of Endocrinology and Metabolism, Kyung Hee University Hospital at Gangdong, Seoul, Republic of Korea; Division of Endocrinology and Metabolism, Department of Internal Medicine, Kyung Hee University School of Medicine, Seoul, Republic of Korea.
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3
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Kim M, Lu L, Dvornikov AV, Ma X, Ding Y, Zhu P, Olson TM, Lin X, Xu X. TFEB Overexpression, Not mTOR Inhibition, Ameliorates RagC S75Y Cardiomyopathy. Int J Mol Sci 2021; 22:5494. [PMID: 34071043 PMCID: PMC8197163 DOI: 10.3390/ijms22115494] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [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: 04/30/2021] [Revised: 05/20/2021] [Accepted: 05/21/2021] [Indexed: 12/29/2022] Open
Abstract
A de novo missense variant in Rag GTPase protein C (RagCS75Y) was recently identified in a syndromic dilated cardiomyopathy (DCM) patient. However, its pathogenicity and the related therapeutic strategy remain unclear. We generated a zebrafish RragcS56Y (corresponding to human RagCS75Y) knock-in (KI) line via TALEN technology. The KI fish manifested cardiomyopathy-like phenotypes and poor survival. Overexpression of RagCS75Y via adenovirus infection also led to increased cell size and fetal gene reprogramming in neonatal rat ventricle cardiomyocytes (NRVCMs), indicating a conserved mechanism. Further characterization identified aberrant mammalian target of rapamycin complex 1 (mTORC1) and transcription factor EB (TFEB) signaling, as well as metabolic abnormalities including dysregulated autophagy. However, mTOR inhibition failed to ameliorate cardiac phenotypes in the RagCS75Y cardiomyopathy models, concomitant with a failure to promote TFEB nuclear translocation. This observation was at least partially explained by increased and mTOR-independent physical interaction between RagCS75Y and TFEB in the cytosol. Importantly, TFEB overexpression resulted in more nuclear TFEB and rescued cardiomyopathy phenotypes. These findings suggest that S75Y is a pathogenic gain-of-function mutation in RagC that leads to cardiomyopathy. A primary pathological step of RagCS75Y cardiomyopathy is defective mTOR-TFEB signaling, which can be corrected by TFEB overexpression, but not mTOR inhibition.
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Affiliation(s)
- Maengjo Kim
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55901, USA; (M.K.); (L.L.); (A.V.D.); (X.M.); (Y.D.); (P.Z.); (X.L.)
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55901, USA;
| | - Linghui Lu
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55901, USA; (M.K.); (L.L.); (A.V.D.); (X.M.); (Y.D.); (P.Z.); (X.L.)
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55901, USA;
- School of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Alexey V. Dvornikov
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55901, USA; (M.K.); (L.L.); (A.V.D.); (X.M.); (Y.D.); (P.Z.); (X.L.)
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55901, USA;
- Department of Cellular and Molecular Medicine, The University of Arizona, Tucson, AZ 85721, USA
| | - Xiao Ma
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55901, USA; (M.K.); (L.L.); (A.V.D.); (X.M.); (Y.D.); (P.Z.); (X.L.)
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55901, USA;
| | - Yonghe Ding
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55901, USA; (M.K.); (L.L.); (A.V.D.); (X.M.); (Y.D.); (P.Z.); (X.L.)
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55901, USA;
| | - Ping Zhu
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55901, USA; (M.K.); (L.L.); (A.V.D.); (X.M.); (Y.D.); (P.Z.); (X.L.)
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55901, USA;
| | - Timothy M. Olson
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55901, USA;
- Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology, Mayo Clinic, Rochester, MN 55901, USA
| | - Xueying Lin
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55901, USA; (M.K.); (L.L.); (A.V.D.); (X.M.); (Y.D.); (P.Z.); (X.L.)
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55901, USA;
| | - Xiaolei Xu
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55901, USA; (M.K.); (L.L.); (A.V.D.); (X.M.); (Y.D.); (P.Z.); (X.L.)
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55901, USA;
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Ballesteros-Álvarez J, Dilshat R, Fock V, Möller K, Karl L, Larue L, Ögmundsdóttir MH, Steingrímsson E. MITF and TFEB cross-regulation in melanoma cells. PLoS One 2020; 15:e0238546. [PMID: 32881934 PMCID: PMC7470386 DOI: 10.1371/journal.pone.0238546] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 08/18/2020] [Indexed: 01/24/2023] Open
Abstract
The MITF, TFEB, TFE3 and TFEC (MiT-TFE) proteins belong to the basic helix-loop-helix family of leucine zipper transcription factors. MITF is crucial for melanocyte development and differentiation, and has been termed a lineage-specific oncogene in melanoma. The three related proteins MITF, TFEB and TFE3 have been shown to be involved in the biogenesis and function of lysosomes and autophagosomes, regulating cellular clearance pathways. Here we investigated the cross-regulatory relationship of MITF and TFEB in melanoma cells. Like MITF, the TFEB and TFE3 genes are expressed in melanoma cells as well as in melanoma tumors, albeit at lower levels. We show that the MITF and TFEB proteins, but not TFE3, directly affect each other's mRNA and protein expression. In addition, the subcellular localization of MITF and TFEB is subject to regulation by the mTOR signaling pathway, which impacts their cross-regulatory relationship at the transcriptional level. Our work shows that the relationship between MITF and TFEB is multifaceted and that the cross-regulatory interactions of these factors need to be taken into account when considering pathways regulated by these proteins.
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Affiliation(s)
- Josué Ballesteros-Álvarez
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, BioMedical Center, University of Iceland, Reykjavík, Iceland
| | - Ramile Dilshat
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, BioMedical Center, University of Iceland, Reykjavík, Iceland
| | - Valerie Fock
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, BioMedical Center, University of Iceland, Reykjavík, Iceland
| | - Katrín Möller
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, BioMedical Center, University of Iceland, Reykjavík, Iceland
| | - Ludwig Karl
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, BioMedical Center, University of Iceland, Reykjavík, Iceland
| | - Lionel Larue
- Institut Curie, PSL Research University, INSERM U1021, Normal and Pathological Development of Melanocytes, Orsay, France
- Univ Paris-Sud, Univ Paris-Saclay, CNRS UMR 3347, Orsay, France
- Equipe Labellisée Ligue Contre le Cancer
| | | | - Eiríkur Steingrímsson
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, BioMedical Center, University of Iceland, Reykjavík, Iceland
- * E-mail:
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Ortigosa A, Fonseca S, Franco-Zorrilla JM, Fernández-Calvo P, Zander M, Lewsey MG, García-Casado G, Fernández-Barbero G, Ecker JR, Solano R. The JA-pathway MYC transcription factors regulate photomorphogenic responses by targeting HY5 gene expression. Plant J 2020; 102:138-152. [PMID: 31755159 DOI: 10.1111/tpj.14618] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 10/28/2019] [Accepted: 11/05/2019] [Indexed: 05/18/2023]
Abstract
Jasmonates are key regulators of the balance between defence and growth in plants. However, the molecular mechanisms by which activation of defence reduces growth are not yet fully understood. Here, we analyze the role of MYC transcription factors (TFs) and jasmonic acid (JA) in photomorphogenic growth. We found that multiple myc mutants share light-associated phenotypes with mutants of the phytochrome B photoreceptor, such as delayed seed germination in the dark and long hypocotyl growth. Overexpression of MYC2 in a phyB background partially suppressed its long hypocotyl phenotype. Transcriptomic analysis of multiple myc mutants confirmed that MYCs are required for full expression of red (R) light-regulated genes, including the master regulator HY5. ChIP-seq analyses revealed that MYC2 and MYC3 bind directly to the promoter of HY5 and that HY5 gene expression and protein levels are compromised in multiple myc mutants. Altogether, our results pinpoint MYCs as photomorphogenic TFs that control phytochrome responses by activating HY5 expression. This has important implications in understanding the trade-off between growth and defence as the same TFs that activate defence responses are photomorphogenic growth regulators.
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Affiliation(s)
- Andrés Ortigosa
- Department of Plant Molecular Genetics, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), 28049, Madrid, Spain
| | - Sandra Fonseca
- Department of Plant Molecular Genetics, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), 28049, Madrid, Spain
| | - José M Franco-Zorrilla
- Genomics Unit, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), 28049, Madrid, Spain
| | - Patricia Fernández-Calvo
- Department of Plant Molecular Genetics, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), 28049, Madrid, Spain
| | - Mark Zander
- Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
- Howard Hughes Medical Institute, The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Mathew G Lewsey
- Department of Animal, Plant and Soil Science, La Trobe University, AgriBio Building, Bundoora, VIC, 3086, Australia
- Australian Research Council Research Hub for Medicinal Agriculture, Centre for AgriBioscience, La Trobe University, AgriBio Building, Bundoora, VIC, 3086, Australia
| | - Gloria García-Casado
- Genomics Unit, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), 28049, Madrid, Spain
| | - Gemma Fernández-Barbero
- Department of Plant Molecular Genetics, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), 28049, Madrid, Spain
| | - Joseph R Ecker
- Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
- Howard Hughes Medical Institute, The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Roberto Solano
- Department of Plant Molecular Genetics, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), 28049, Madrid, Spain
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Bao Q, Zhang B, Suo Y, Liu C, Yang Q, Zhang K, Yuan M, Yuan M, Zhang Y, Li G. Intermittent hypoxia mediated by TSP1 dependent on STAT3 induces cardiac fibroblast activation and cardiac fibrosis. eLife 2020; 9:e49923. [PMID: 31934850 PMCID: PMC6992386 DOI: 10.7554/elife.49923] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [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: 07/04/2019] [Accepted: 01/10/2020] [Indexed: 12/14/2022] Open
Abstract
Intermittent hypoxia (IH) is the predominant pathophysiological disturbance in obstructive sleep apnea (OSA), known to be independently associated with cardiovascular diseases. However, the effect of IH on cardiac fibrosis and molecular events involved in this process are unclear. Here, we tested IH in angiotensin II (Ang II)-induced cardiac fibrosis and signaling linked to fibroblast activation. IH triggered cardiac fibrosis and aggravated Ang II-induced cardiac dysfunction in mice. Plasma thrombospondin-1 (TSP1) content was upregulated in both IH-exposed mice and OSA patients. Moreover, both in vivo and in vitro results showed IH-induced cardiac fibroblast activation and increased TSP1 expression in cardiac fibroblasts. Mechanistically, phosphorylation of STAT3 at Tyr705 mediated the IH-induced TSP1 expression and fibroblast activation. Finally, STAT3 inhibitor S3I-201 or AAV9 carrying a periostin promoter driving the expression of shRNA targeting Stat3 significantly attenuated the synergistic effects of IH and Ang II on cardiac fibrosis in mice. This work suggests a potential therapeutic strategy for OSA-related fibrotic heart disease.
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Affiliation(s)
- Qiankun Bao
- Tianjin key laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of CardiologyThe Second Hospital of Tianjin Medical UniversityTianjinChina
| | - Bangying Zhang
- Tianjin key laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of CardiologyThe Second Hospital of Tianjin Medical UniversityTianjinChina
| | - Ya Suo
- Tianjin key laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of CardiologyThe Second Hospital of Tianjin Medical UniversityTianjinChina
| | - Chen Liu
- Department of Clinical LaboratoryPeking University People's HospitalBeijingChina
| | - Qian Yang
- Tianjin key laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of CardiologyThe Second Hospital of Tianjin Medical UniversityTianjinChina
| | - Kai Zhang
- Tianjin key laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of CardiologyThe Second Hospital of Tianjin Medical UniversityTianjinChina
| | - Ming Yuan
- Tianjin key laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of CardiologyThe Second Hospital of Tianjin Medical UniversityTianjinChina
| | - Meng Yuan
- Tianjin key laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of CardiologyThe Second Hospital of Tianjin Medical UniversityTianjinChina
| | - Yue Zhang
- Tianjin key laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of CardiologyThe Second Hospital of Tianjin Medical UniversityTianjinChina
| | - Guangping Li
- Tianjin key laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of CardiologyThe Second Hospital of Tianjin Medical UniversityTianjinChina
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Sharma A, Rather GA, Misra P, Dhar MK, Lattoo SK. Jasmonate responsive transcription factor WsMYC2 regulates the biosynthesis of triterpenoid withanolides and phytosterol via key pathway genes in Withania somnifera (L.) Dunal. Plant Mol Biol 2019; 100:543-560. [PMID: 31090025 DOI: 10.1007/s11103-019-00880-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [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: 01/02/2019] [Accepted: 05/08/2019] [Indexed: 06/09/2023]
Abstract
Functional characterization of WsMYC2 via artificial microRNA mediated silencing and transient over-expression displayed significant regulatory role vis-à-vis withanolides and stigmasterol biosyntheses in Withania somnifera. Further, metabolic intensification corroborated well with higher expression levels of putative pathway genes. Additionally, copious expression of WsMYC2 in response to exogenous elicitors resulted in enhanced withanolides production. Withania somnifera, a high value multipurpose medicinal plant, is a rich reservoir of structurally diverse and biologically active triterpenoids known as withanolides. W. somnifera has been extensively pursued vis-à-vis pharmacological and chemical studies. Nonetheless, there exists fragmentary knowledge regarding the metabolic pathway and the regulatory aspects of withanolides biosynthesis. Against this backdrop, a jasmonate-responsive MYC2 transcription factor was identified and functionally characterized from W. somnifera. In planta transient over-expression of WsMYC2 showed significant enhancement of mRNA transcript levels which corroborated well with the enhanced content of withanolides and stigmasterol. Further, a comparative analysis of expression levels of some of the genes of triterpenoid pathway viz. WsCAS, WsCYP85A, WsCYP90B and WsCYP710A in corroboration with the over-expression and silencing of WsMYC2 suggested its positive influence on their regulation. These corroboratory approaches suggest that WsMYC2 has cascading effect on over-expression of multiple pathway genes leading to the increased triterpenoid biosynthesis in infiltered plants. Further, the functional validation of WsMYC2 was carried out by artificial micro-RNA mediated silencing. It resulted in significant reduction of withanolides and stigmasterol levels, indicative of crucial role of WsMYC2 in the regulation of their biosyntheses. Taken together, these non-complementary approaches provided unambiguous understanding of the regulatory role of WsMYC2 in context to withanolides and stigmasterol biosyntheses. Furthermore, the upstream promoter of WsMYC2 presented several cis-regulatory elements primarily related to phytohormone responsiveness. WsMYC2 displayed inducible nature in response to MeJA. It had substantial influence on the higher expression of WsMYC2 which was in consonance with enhanced accumulation of withanolides.
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Affiliation(s)
- Arti Sharma
- Plant Biotechnology Division, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu Tawi, 180001, India
| | - Gulzar A Rather
- Plant Biotechnology Division, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu Tawi, 180001, India
| | - Prashant Misra
- Plant Biotechnology Division, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu Tawi, 180001, India
| | - Manoj K Dhar
- School of Biotechnology, Department of Life Sciences, University of Jammu, Jammu Tawi, 180006, India.
| | - Surrinder K Lattoo
- Plant Biotechnology Division, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu Tawi, 180001, India.
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Bai J, He Z, Li Y, Jiang X, Yu H, Tan Q. Mono-2-ethylhexyl phthalate induces the expression of genes involved in fatty acid synthesis in HepG2 cells. Environ Toxicol Pharmacol 2019; 69:104-111. [PMID: 31004931 DOI: 10.1016/j.etap.2019.04.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [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: 10/28/2018] [Revised: 03/28/2019] [Accepted: 04/08/2019] [Indexed: 06/09/2023]
Abstract
Mono-2-ethylhexyl phthalate (MEHP) is a major bioactive metabolite in the widely used industrial plasticizer diethylhexyl phthalate (DEHP) that has been found to be toxic to the liver. The aim of this study is to determine whether MEHP exposure can change the expression of fatty acid metabolism-related genes in HepG2 cells, which might be related to non-alcoholic fatty liver disease (NAFLD). The results revealed that exposure to MEHP promoted lipid accumulation in HepG2 cells. The levels of intracellular triglycerides in the hepatocytes increased after exposure to 0.8-100 μM MEHP for 24 h and 48 h. The genetic expressions of SREBP-1c, ChREBP, ACC1, FASN, and SCD significantly increased at 6 h after exposure to MEHP. At 24 h, the expression of the SREBP-1c and ChREBP genes remained increased, while the expression of the FASN and SCD genes decreased. At 48 h, the expression of SREBP-1c, ChREBP, ACC1, FASN, and SCD decreased. Furthermore, the levels of proteins including ACC1, FASN, SCD, and ChREBP (except SREBP-1c) increased at 24 h. These findings suggest that MEHP exposure can promote fatty acid synthesis in hepatocytes by regulating the expression of relevant genes and proteins, contributing to NAFLD.
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Affiliation(s)
- Jianying Bai
- Department of Environmental Health, School of Public Health, Shanxi Medical University, Taiyuan, 030001, China.
| | - Zhen He
- Department of Environmental Health, School of Public Health, Shanxi Medical University, Taiyuan, 030001, China
| | - Yaofu Li
- Department of Environmental Health, School of Public Health, Shanxi Medical University, Taiyuan, 030001, China
| | - Xuexia Jiang
- Department of Environmental Health, School of Public Health, Shanxi Medical University, Taiyuan, 030001, China
| | - Hongmei Yu
- Department of Health Statistics, School of Public Health, Shanxi Medical University, Taiyuan, 030001, China
| | - Qing Tan
- Department of Environmental Health, School of Public Health, Shanxi Medical University, Taiyuan, 030001, China
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Nakazaki A, Yamada K, Kunieda T, Sugiyama R, Hirai MY, Tamura K, Hara-Nishimura I, Shimada T. Leaf Endoplasmic Reticulum Bodies Identified in Arabidopsis Rosette Leaves Are Involved in Defense against Herbivory. Plant Physiol 2019; 179:1515-1524. [PMID: 30696747 PMCID: PMC6446793 DOI: 10.1104/pp.18.00984] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 01/15/2019] [Indexed: 05/20/2023]
Abstract
ER bodies are endoplasmic reticulum (ER)-derived organelles specific to the order Brassicales and are thought to function in plant defense against insects and pathogens. ER bodies are generally classified into two types: constitutive ER bodies in the epidermal cells of seedlings, and wound-inducible ER bodies in rosette leaves. Herein, we reveal a third type of ER body found in Arabidopsis (Arabidopsis thaliana) rosette leaves and designate them "leaf ERbodies" (L-ER bodies). L-ER bodies constitutively occurred in specific cells of the rosette leaves: marginal cells, epidermal cells covering the midrib, and giant pavement cells. The distribution of L-ER bodies was closely associated with the expression profile of the basic helix-loop-helix transcription factor NAI1, which is responsible for constitutive ER-body formation. L-ER bodies were seldom observed in nai1 mutant leaves, indicating that NAI1 is involved in L-ER body formation. Confocal imaging analysis revealed that L-ER bodies accumulated two types of β-glucosidases: PYK10, the constitutive ER-body β-glucosidase; and BETA-GLUCOSIDASE18 (BGLU18), the wound-inducible ER-body β-glucosidase. Combined with the absence of L-ER bodies in the bglu18 pyk10 mutant, these results indicate that BGLU18 and PYK10 are the major components of L-ER bodies. A subsequent feeding assay with the terrestrial isopod Armadillidium vulgare revealed that bglu18 pyk10 leaves were severely damaged as a result of herbivory. In addition, the bglu18 pyk10 mutant was defective in the hydrolysis of 4-methoxyindol-3-ylmethyl glucosinolate These results suggest that L-ER bodies are involved in the production of defensive compound(s) from 4-methoxyindol-3-ylmethyl glucosinolate that protect Arabidopsis leaves against herbivory attack.
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Affiliation(s)
- Akiko Nakazaki
- Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Kenji Yamada
- Malopolska Center of Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Tadashi Kunieda
- Faculty of Science and Engineering, Konan University, Kobe 658-8501, Japan
| | - Ryosuke Sugiyama
- RIKEN Center for Sustainable Resource Science, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Masami Yokota Hirai
- RIKEN Center for Sustainable Resource Science, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Kentaro Tamura
- Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | | | - Tomoo Shimada
- Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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10
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Min JH, Park CR, Jang YH, Ju HW, Lee KH, Lee S, Kim CS. A basic helix-loop-helix 104 (bHLH104) protein functions as a transcriptional repressor for glucose and abscisic acid signaling in Arabidopsis. Plant Physiol Biochem 2019; 136:34-42. [PMID: 30639920 DOI: 10.1016/j.plaphy.2019.01.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [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: 10/21/2018] [Revised: 01/05/2019] [Accepted: 01/05/2019] [Indexed: 06/09/2023]
Abstract
Transduction of glucose (Glc) signaling is critical for plant development, metabolism, and stress responses. However, identifying initial Glc sensing and response stimulating mechanisms in plants has been difficult due to dual functions of glucose as energy sources and signaling component. A basic Helix-Loop-Helix 104 (bHLH104) protein is a homolog of bHLH34 previously isolated from Arabidopsis that functions as a transcriptional activator of Glc and abscisic acid (ABA) responses. In this study, we characterized bHLH104 as a transcription factor that binds to the regulatory region of Arabidopsis Plasma membrane Glc-responsive Regulator (AtPGR) gene. The bHLH104 binds to 5'-AANA-3' element of the promoter region of AtPGR in vitro and represses beta-glucuronidase (GUS) activity in AtPGR promoter-GUS transgenic plants. Genetic approaches show that bHLH104 positively regulates Glc and abscisic acid (ABA) response. These results suggest that bHLH104 is involved in Glc- and ABA-mediated signaling pathway. Taken together, these findings provide evidence that bHLH104 is an important transcription regulator in plant-sensitivity to Glc and ABA signaling.
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Affiliation(s)
- Ji-Hee Min
- Department of Plant Biotechnology, Chonnam National University, Gwangju, 61186, Republic of Korea
| | - Cho-Rong Park
- Department of Plant Biotechnology, Chonnam National University, Gwangju, 61186, Republic of Korea
| | - Yun-Ha Jang
- Department of Plant Biotechnology, Chonnam National University, Gwangju, 61186, Republic of Korea
| | - Hyun-Woo Ju
- Department of Plant Biotechnology, Chonnam National University, Gwangju, 61186, Republic of Korea
| | - Kyeong-Hwan Lee
- Department of Rural and Biosystems Engineering, Agricultural Robotics and Automation Research Center, Chonnam National University, Gwangju, 61186, Republic of Korea
| | - Sungbeom Lee
- Research Division for Biotechnology, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup-si, Jeollabuk-do, 56212, Republic of Korea
| | - Cheol Soo Kim
- Department of Plant Biotechnology, Chonnam National University, Gwangju, 61186, Republic of Korea.
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11
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Wang LT, Wang SN, Chiou SS, Liu KY, Chai CY, Chiang CM, Huang SK, Yokoyama KK, Hsu SH. TIP60-dependent acetylation of the SPZ1-TWIST complex promotes epithelial-mesenchymal transition and metastasis in liver cancer. Oncogene 2019; 38:518-532. [PMID: 30154425 PMCID: PMC6345675 DOI: 10.1038/s41388-018-0457-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [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: 01/17/2018] [Revised: 05/28/2018] [Accepted: 06/03/2018] [Indexed: 02/08/2023]
Abstract
Metastasis is the main cause of cancer mortality. However, the triggering mechanisms and regulation of epithelial-mesenchymal transition (EMT) factors in the commitment of metastasis have not been well characterized. Spermatogenic Zip 1 (SPZ1) acts as a proto-oncogene and an upstream regulator of EMT during tumorigenesis. Here we report that the HIV-1 Tat-interacting protein 60 kDa (Tip60) acetyltransferase mediates acetylation at lysine residues of SPZ1 at positions 369 and 374, and of TWIST1 at positions 73 and 76, which are required for SPZ1-TWIST1 complex formation and cancer cell migration in vitro and in vivo. Ectopic SPZ1 and TWIST1 expression, but not that of TWIST1 alone, enhanced vascular endothelial growth factor (VEGF) expression via the recruitment of bromodomain-containing protein 4 (BRD4), thus enhancing RNA-Pol II-dependent transcription and inducing metastasis. Neutralization of VEGF using humanized monoclonal antibodies such as Avastin, effectively abrogated the EMT and oncogenesis induced by the acetylated SPZ1-TWIST1 complex. Our findings highlight the importance of acetylation signaling in the SPZ1-TWIST1-BRD4 axis in the mediation of EMT and its regulation during tumor initiation and metastasis.
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Affiliation(s)
- Li-Ting Wang
- Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan
| | - Shen-Nien Wang
- Department of Surgery, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan
- Pingtung Hospital, Ministry of Health and Welfare, Pingtung 900, Taiwan
| | - Shyh-Shin Chiou
- Department of Pediatrics, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan
- Division of Hematology-Oncology, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan
| | - Kwei-Yan Liu
- Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan
| | - Chee-Yin Chai
- Department of Pathology, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan
| | - Cheng-Ming Chiang
- Simmons Comprehensive Cancer Center, Departments of Pharmacology and Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8807, USA
| | - Shau-Ku Huang
- Division of Environmental Health and Occupational Medicine, National Health Research Institutes, 115, Zhunan, Taiwan
| | - Kazunari K Yokoyama
- Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
- Center of Infectious Disease and Cancer Research, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
- Center for Stem Cell Research, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
- Department of Molecular Preventive Medicine, Graduate School of Medicine, the University of Tokyo, Tokyo, 113-0033, Japan.
| | - Shih-Hsien Hsu
- Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
- Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
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Song Z, Xiaoli AM, Yang F. Regulation and Metabolic Significance of De Novo Lipogenesis in Adipose Tissues. Nutrients 2018; 10:nu10101383. [PMID: 30274245 PMCID: PMC6213738 DOI: 10.3390/nu10101383] [Citation(s) in RCA: 217] [Impact Index Per Article: 36.2] [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: 08/29/2018] [Revised: 09/20/2018] [Accepted: 09/21/2018] [Indexed: 12/20/2022] Open
Abstract
De novo lipogenesis (DNL) is a complex and highly regulated process in which carbohydrates from circulation are converted into fatty acids that are then used for synthesizing either triglycerides or other lipid molecules. Dysregulation of DNL contributes to human diseases such as obesity, type 2 diabetes, and cardiovascular diseases. Thus, the lipogenic pathway may provide a new therapeutic opportunity for combating various pathological conditions that are associated with dysregulated lipid metabolism. Hepatic DNL has been well documented, but lipogenesis in adipocytes and its contribution to energy homeostasis and insulin sensitivity are less studied. Recent reports have gained significant insights into the signaling pathways that regulate lipogenic transcription factors and the role of DNL in adipose tissues. In this review, we will update the current knowledge of DNL in white and brown adipose tissues with the focus on transcriptional, post-translational, and central regulation of DNL. We will also summarize the recent findings of adipocyte DNL as a source of some signaling molecules that critically regulate energy metabolism.
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Affiliation(s)
- Ziyi Song
- Departments of Medicine and Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| | - Alus M Xiaoli
- Departments of Medicine and Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| | - Fajun Yang
- Departments of Medicine and Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
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13
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Zhang Y, Higgins CB, Mayer AL, Mysorekar IU, Razani B, Graham MJ, Hruz PW, DeBosch BJ. TFEB-dependent induction of thermogenesis by the hepatocyte SLC2A inhibitor trehalose. Autophagy 2018; 14:1959-1975. [PMID: 29996716 PMCID: PMC6152536 DOI: 10.1080/15548627.2018.1493044] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 06/13/2018] [Accepted: 06/18/2018] [Indexed: 02/08/2023] Open
Abstract
The macroautophagy/autophagy-inducing disaccharide, trehalose, has been proposed to be a promising therapeutic agent against neurodegenerative and cardiometabolic diseases. We recently showed that trehalose attenuates hepatic steatosis in part by blocking hepatocyte glucose transport to induce hepatocyte autophagic flux. However, although every major demonstration of trehalose action invokes activating autophagic flux as its primary function, the mechanism of action of trehalose in whole-body energy metabolism remains poorly defined. Here, we demonstrate that trehalose induces hepatocyte TFEB (transcription factor EB)-dependent thermogenesis in vivo, concomitant with upregulation of hepatic and white adipose expression of UCP1 (uncoupling protein 1 [mitochondrial, protein carrier]). Mechanistically, we provide evidence that hepatocyte fasting transcriptional and metabolic responses depend upon PPARGC1A (peroxisome proliferative activated receptor, gamma, coactivator 1 alpha), TFEB, and FGF21 (fibroblast growth factor 21) signaling. Strikingly, hepatocyte-selective TFEB knockdown abrogated trehalose induction of thermogenesis and white adipose tissue UCP1 upregulation in vivo. In contrast, we found that trehalose action on thermogenesis was independent of LEP (leptin) and the autophagy pathway, as there was robust thermogenic induction in trehalose-treated ob/ob, Becn1, Atg16l1, and Epg5 mutant mice. We conclude that trehalose induces metabolically favorable effects on whole-body thermogenesis in part via hepatocyte-centered fasting-like mechanisms that appear to be independent of autophagic flux. Our findings elucidate a novel mechanism by which trehalose acts as a metabolic therapeutic agent by activating hepatic fasting responses. More broadly, the hepatic glucose fasting response may be of clinical utility against overnutrition-driven disease, such as obesity and type 2 diabetes mellitus.
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Affiliation(s)
- Yiming Zhang
- Pediatrics, Washington University School of Medicine, St. Louis, MO, USA
| | | | - Allyson L. Mayer
- Pediatrics, Washington University School of Medicine, St. Louis, MO, USA
| | - Indira U. Mysorekar
- Obstetrics and Gynecology, Washington University School of Medicine, St. Louis, MO, USA
- Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Babak Razani
- Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Mark J. Graham
- IONIS Pharmaceuticals, Washington University School of Medicine, St. Louis, MO, USA
| | - Paul W. Hruz
- Pediatrics, Washington University School of Medicine, St. Louis, MO, USA
- Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Brian J. DeBosch
- Pediatrics, Washington University School of Medicine, St. Louis, MO, USA
- Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, USA
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14
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Feng YJ, Wang J, Cao ZJ, Li D, Huo HY, Zhang XM, Jiao XY. [Angiotensin II promotes the expression of TXNIP through angiotensin II type 1 receptor in islet β cells]. Sheng Li Xue Bao 2018; 70:149-157. [PMID: 29691579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
This study investigated the effect of angiotensin II (Ang II) on apoptosis and thioredoxin-interacting protein (TXNIP) expression in INS-1 islet cells and the underlying mechanism. INS-1 cells cultured in vitro were treated with different concentration of Ang II for different time, and the viability was measured using cell counting kit-8 (CCK-8). After treatment with 1 × 10-6 mol/L Ang II for 24 h, flow cytometry and Western blot were used to measure the cell apoptosis, and Western blot was used to analyze the protein expression of TXNIP, carbohydrate response element-binding protein (ChREBP) and angiotensin II type 1 receptor (AT1R). Real-time PCR was used to detect TXNIP and ChREBP mRNA expression. IF/ICC was used to observe the TXNIP, ChREBP and AT1R expression. The results showed that Ang II reduced cell viability and induced the expression of TXNIP in a dose- and time-dependent manner (P < 0.05, n = 6) compared with the control group. Ang II induced apoptosis and up-regulated the expression of ChREBP and AT1R (P < 0.05, n = 6). AT1R inhibitor, telmisartan (TM), blocked Ang II-induced TXNIP and ChREBP overexpression (P < 0.05, n = 6) and inhibited Ang II-induced apoptosis. Taken together, Ang II increased ChREBP activation through AT1R, which subsequently increased TXNIP expression and promoted cell apoptosis. These findings suggest a therapeutic potential of targeting TXNIP in preventing Ang II-induced INS-1 cell apoptosis in diabetes.
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Affiliation(s)
- Yan-Jin Feng
- Department of Physiology, Key Laboratory for Cellular Physiology of Ministry of Education, Shanxi Medical University, Taiyuan 030001, China
| | - Jin Wang
- Department of Physiology, Key Laboratory for Cellular Physiology of Ministry of Education, Shanxi Medical University, Taiyuan 030001, China
| | - Zhu-Jie Cao
- Department of Physiology, Key Laboratory for Cellular Physiology of Ministry of Education, Shanxi Medical University, Taiyuan 030001, China
| | - Dan Li
- Department of Physiology, Key Laboratory for Cellular Physiology of Ministry of Education, Shanxi Medical University, Taiyuan 030001, China
| | - Hai-Yan Huo
- Department of Physiology, Key Laboratory for Cellular Physiology of Ministry of Education, Shanxi Medical University, Taiyuan 030001, China
| | - Xu-Mei Zhang
- Department of Physiology, Key Laboratory for Cellular Physiology of Ministry of Education, Shanxi Medical University, Taiyuan 030001, China
| | - Xiang-Ying Jiao
- Department of Physiology, Key Laboratory for Cellular Physiology of Ministry of Education, Shanxi Medical University, Taiyuan 030001, China.
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15
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Pehote G, Bodas M, Brucia K, Vij N. Cigarette Smoke Exposure Inhibits Bacterial Killing via TFEB-Mediated Autophagy Impairment and Resulting Phagocytosis Defect. Mediators Inflamm 2017; 2017:3028082. [PMID: 29445254 PMCID: PMC5763241 DOI: 10.1155/2017/3028082] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2017] [Accepted: 10/03/2017] [Indexed: 01/07/2023] Open
Abstract
INTRODUCTION Cigarette smoke (CS) exposure is the leading risk factor for COPD-emphysema pathogenesis. A common characteristic of COPD is impaired phagocytosis that causes frequent exacerbations in patients leading to increased morbidity. However, the underlying mechanism is unclear. Hence, we investigated if CS exposure causes autophagy impairment as a mechanism for diminished bacterial clearance via phagocytosis by utilizing murine macrophages (RAW264.7 cells) and Pseudomonas aeruginosa (PA01-GFP) as an experimental model. METHODS Briefly, RAW cells were treated with cigarette smoke extract (CSE), chloroquine (autophagy inhibitor), TFEB-shRNA, CFTR(inh)-172, and/or fisetin prior to bacterial infection for functional analysis. RESULTS Bacterial clearance of PA01-GFP was significantly impaired while its survival was promoted by CSE (p < 0.01), autophagy inhibition (p < 0.05; p < 0.01), TFEB knockdown (p < 0.01; p < 0.001), and inhibition of CFTR function (p < 0.001; p < 0.01) in comparison to the control group(s) that was significantly recovered by autophagy-inducing antioxidant drug, fisetin, treatment (p < 0.05; p < 0.01; and p < 0.001). Moreover, investigations into other pharmacological properties of fisetin show that it has significant mucolytic and bactericidal activities (p < 0.01; p < 0.001), which warrants further investigation. CONCLUSIONS Our data suggests that CS-mediated autophagy impairment as a critical mechanism involved in the resulting phagocytic defect, as well as the therapeutic potential of autophagy-inducing drugs in restoring is CS-impaired phagocytosis.
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Affiliation(s)
- Garrett Pehote
- College of Medicine, Central Michigan University, Mount Pleasant, MI, USA
| | - Manish Bodas
- College of Medicine, Central Michigan University, Mount Pleasant, MI, USA
| | - Kathryn Brucia
- College of Medicine, Central Michigan University, Mount Pleasant, MI, USA
| | - Neeraj Vij
- College of Medicine, Central Michigan University, Mount Pleasant, MI, USA
- Department of Pediatrics and Pulmonary Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Wang C, Yao X, Yu D, Liang G. Fe-deficiency-induced expression of bHLH104 enhances Fe-deficiency tolerance of Arabidopsis thaliana. Planta 2017; 246:421-431. [PMID: 28451750 DOI: 10.1007/s00425-017-2703-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [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: 03/20/2017] [Accepted: 04/20/2017] [Indexed: 06/07/2023]
Abstract
Expression of bHLH104 - GFP driven by the MYB72 promoter improves plants' tolerance to Fe deficiency and increases seed Fe concentrations. Iron (Fe) deficiency causes reduced crop yield and quality. In humans, Fe deficiency is directly associated with Fe-deficiency anemia. Therefore, breeding Fe-deficiency tolerant and Fe-enriched plants are an ideal approach to deal with these problems. Here, different strategies were explored to generate Fe-deficiency tolerant and Fe-enriched plants. Unexpectedly, the overexpression of Fe-deficiency responsive genes (IRT1, MYB72, and bHLH100) resulted in enhanced sensitivity to Fe deficiency, including leaf chlorosis and short roots under Fe-deficiency conditions. Next, three different types of Fe-deficiency responsive promoters (Pro IRT1 , Pro MYB72, and Pro bHLH100 ) were used to drive the expression of bHLH104-GFP fusion gene in Arabidopsis. Pro IRT1 :bHLH104-GFP plants showed the enhanced sensitivity to Fe deficiency on Fe-deficient media and the reduced fertility in alkaline soil. In contrast, Pro bHLH100 :bHLH104-GFP plants displayed a slight tolerance to Fe deficiency and Pro MYB72 :bHLH104-GFP plants had a significant advantage in growth in alkaline soil, including increased root length, chlorophyll, and biomass. Further analysis revealed that the expression of Fe-deficiency responsive genes was dramatically upregulated in both Pro MYB72 :bHLH104-GFP and Pro bHLH100 :bHLH104-GFP plants under Fe-deficiency conditions. When grown in alkaline soil, Pro MYB72 :bHLH104-GFP plants greatly improved the seed yield and Fe concentration. These results are fundamental for plant manipulation approaches to modify tolerance to Fe deficiency and Fe accumulation through alterations of bHLH104 gene expression.
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Affiliation(s)
- Ce Wang
- Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiani Yao
- Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Diqiu Yu
- Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China.
| | - Gang Liang
- Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China.
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17
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Nabar NR, Kehrl JH. The Transcription Factor EB Links Cellular Stress to the Immune Response
. Yale J Biol Med 2017; 90:301-315. [PMID: 28656016 PMCID: PMC5482306] [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] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
The transcription factor EB (TFEB) is the master transcriptional regulator of autophagy and lysosome biogenesis. Recent advances have led to a paradigm shift in our understanding of lysosomes from a housekeeping cellular waste bin to a dynamically regulated pathway that is efficiently turned up or down based on cellular needs. TFEB coordinates the cellular response to nutrient deprivation and other forms of cell stress through the lysosome system, and regulates a myriad of cellular processes associated with this system including endocytosis, phagocytosis, autophagy, and lysosomal exocytosis. Autophagy and the endolysosomal system are critical to both the innate and adaptive arms of the immune system, with functions in effector cell priming and direct pathogen clearance. Recent studies have linked TFEB to the regulation of the immune response through the endolysosmal pathway and by direct transcriptional activation of immune related genes. In this review, we discuss the current understanding of TFEB's function and the molecular mechanisms behind TFEB activation. Finally, we discuss recent advances linking TFEB to the immune response that positions lysosomal signaling as a potential target for immune modulation.
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Affiliation(s)
- Neel R. Nabar
- B cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institutes of Allergy and Infection Disease, National Institutes of Health, Bethesda, MD
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
| | - John H. Kehrl
- B cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institutes of Allergy and Infection Disease, National Institutes of Health, Bethesda, MD
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18
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Iizuka K. The Role of Carbohydrate Response Element Binding Protein in Intestinal and Hepatic Fructose Metabolism. Nutrients 2017; 9:nu9020181. [PMID: 28241431 PMCID: PMC5331612 DOI: 10.3390/nu9020181] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [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: 01/17/2017] [Revised: 02/16/2017] [Accepted: 02/20/2017] [Indexed: 12/21/2022] Open
Abstract
Many articles have discussed the relationship between fructose consumption and the incidence of obesity and related diseases. Fructose is absorbed in the intestine and metabolized in the liver to glucose, lactate, glycogen, and, to a lesser extent, lipids. Unabsorbed fructose causes bacterial fermentation, resulting in irritable bowl syndrome. Therefore, understanding the mechanisms underlying intestinal and hepatic fructose metabolism is important for the treatment of metabolic syndrome and fructose malabsorption. Carbohydrate response element binding protein (ChREBP) is a glucose-activated transcription factor that controls approximately 50% of de novo lipogenesis in the liver. ChREBP target genes are involved in glycolysis (Glut2, liver pyruvate kinase), fructolysis (Glut5, ketohexokinase), and lipogenesis (acetyl CoA carboxylase, fatty acid synthase). ChREBP gene deletion protects against high sucrose diet-induced and leptin-deficient obesity, because Chrebp−/− mice cannot consume fructose or sucrose. Moreover, ChREBP contributes to some of the physiological effects of fructose on sweet taste preference and glucose production through regulation of ChREBP target genes, such as fibroblast growth factor-21 and glucose-6-phosphatase catalytic subunits. Thus, ChREBP might play roles in fructose metabolism. Restriction of excess fructose intake will be beneficial for preventing not only metabolic syndrome but also irritable bowl syndrome.
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Affiliation(s)
- Katsumi Iizuka
- Department of Diabetes and Endocrinology, Graduate School of Medicine, Gifu University, Gifu 501-1194, Japan.
- Gifu University Hospital Center for Nutritional Support and Infection Control, Gifu 501-1194, Japan.
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19
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Liu N, Staswick PE, Avramova Z. Memory responses of jasmonic acid-associated Arabidopsis genes to a repeated dehydration stress. Plant Cell Environ 2016; 39:2515-2529. [PMID: 27451106 DOI: 10.1111/pce.12806] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [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: 03/18/2016] [Revised: 07/13/2016] [Accepted: 07/17/2016] [Indexed: 05/22/2023]
Abstract
Dehydration stress activates numerous genes co-regulated by diverse signaling pathways. Upon repeated exposures, however, a subset of these genes does not respond maintaining instead transcription at their initial pre-stressed levels ('revised-response' genes). Most of these genes are involved in jasmonic acid (JA) biosynthesis, JA-signaling and JA-mediated stress responses. How these JA-associated genes are regulated to provide different responses to similar dehydration stresses is an enigma. Here, we investigate molecular mechanisms that contribute to this transcriptional behavior. The memory-mechanism is stress-specific: one exposure to dehydration stress or to abscisic acid (ABA) is required to prevent transcription in the second. Both ABA-mediated and JA-mediated pathways are critical for the activation of these genes, but the two signaling pathways interact differently during a single or multiple encounters with dehydration stress. Synthesis of JA during the first (S1) but not the second dehydration stress (S2) accounts for the altered transcriptional responses. We propose a model for these memory responses, wherein lack of MYC2 and of JA synthesis in S2 is responsible for the lack of expression of downstream genes. The similar length of the memory displayed by different memory-type genes suggests biological relevance for transcriptional memory as a gene-regulating mechanism during recurring bouts of drought.
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Affiliation(s)
- Ning Liu
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Paul E Staswick
- Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Zoya Avramova
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA.
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Ahn B, Soundarapandian MM, Sessions H, Peddibhotla S, Roth GP, Li JL, Sugarman E, Koo A, Malany S, Wang M, Yea K, Brooks J, Leone TC, Han X, Vega RB, Kelly DP. MondoA coordinately regulates skeletal myocyte lipid homeostasis and insulin signaling. J Clin Invest 2016; 126:3567-79. [PMID: 27500491 DOI: 10.1172/jci87382] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 06/09/2016] [Indexed: 01/09/2023] Open
Abstract
Intramuscular lipid accumulation is a common manifestation of chronic caloric excess and obesity that is strongly associated with insulin resistance. The mechanistic links between lipid accumulation in myocytes and insulin resistance are not completely understood. In this work, we used a high-throughput chemical biology screen to identify a small-molecule probe, SBI-477, that coordinately inhibited triacylglyceride (TAG) synthesis and enhanced basal glucose uptake in human skeletal myocytes. We then determined that SBI-477 stimulated insulin signaling by deactivating the transcription factor MondoA, leading to reduced expression of the insulin pathway suppressors thioredoxin-interacting protein (TXNIP) and arrestin domain-containing 4 (ARRDC4). Depleting MondoA in myocytes reproduced the effects of SBI-477 on glucose uptake and myocyte lipid accumulation. Furthermore, an analog of SBI-477 suppressed TXNIP expression, reduced muscle and liver TAG levels, enhanced insulin signaling, and improved glucose tolerance in mice fed a high-fat diet. These results identify a key role for MondoA-directed programs in the coordinated control of myocyte lipid balance and insulin signaling and suggest that this pathway may have potential as a therapeutic target for insulin resistance and lipotoxicity.
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Maurya JP, Sethi V, Gangappa SN, Gupta N, Chattopadhyay S. Interaction of MYC2 and GBF1 results in functional antagonism in blue light-mediated Arabidopsis seedling development. Plant J 2015; 83:439-450. [PMID: 26047210 DOI: 10.1111/tpj.12899] [Citation(s) in RCA: 21] [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] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Revised: 05/24/2015] [Accepted: 05/28/2015] [Indexed: 06/04/2023]
Abstract
Regulations of Arabidopsis seedling growth by two proteins, which belong to different classes of transcription factors, are poorly understood. MYC2 and GBF1 belong to bHLH and bZIP classes of transcription factors, respectively, and function in cryptochrome-mediated blue light signaling. Here, we have investigated the molecular and functional interrelation of MYC2 and GBF1 in blue light-mediated photomorphogenesis. Our study reveals that MYC2 and GBF1 colocalize and physically interact in the nucleus. This interaction requires the N-terminal domain of each protein. The atmyc2 gbf1 double mutant analyses and transgenic studies have revealed that MYC2 and GBF1 act antagonistically and inhibit the activity of each other to regulate hypocotyl growth and several other biological processes. This study further reveals that MYC2 and GBF1 bind to HYH promoter and inhibit each other through non-DNA binding bHLH-bZIP heterodimers. These results, taken together, provide insights into the mechanistic view on the concerted regulatory role of MYC2 and GBF1 in Arabidopsis seedling development.
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Affiliation(s)
- Jay P Maurya
- Department of Biotechnology, National Institute of Technology, Durgapur, 713209, India
| | - Vishmita Sethi
- Department of Biotechnology, National Institute of Technology, Durgapur, 713209, India
| | | | - Nisha Gupta
- Department of Biotechnology, National Institute of Technology, Durgapur, 713209, India
| | - Sudip Chattopadhyay
- Department of Biotechnology, National Institute of Technology, Durgapur, 713209, India
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22
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Qi T, Wang J, Huang H, Liu B, Gao H, Liu Y, Song S, Xie D. Regulation of Jasmonate-Induced Leaf Senescence by Antagonism between bHLH Subgroup IIIe and IIId Factors in Arabidopsis. Plant Cell 2015; 27:1634-49. [PMID: 26071420 PMCID: PMC4498205 DOI: 10.1105/tpc.15.00110] [Citation(s) in RCA: 176] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 05/04/2015] [Accepted: 05/26/2015] [Indexed: 05/20/2023]
Abstract
Plants initiate leaf senescence to relocate nutrients and energy from aging leaves to developing tissues or storage organs for growth, reproduction, and defense. Leaf senescence, the final stage of leaf development, is regulated by various environmental stresses, developmental cues, and endogenous hormone signals. Jasmonate (JA), a lipid-derived phytohormone essential for plant defense and plant development, serves as an important endogenous signal to activate senescence-associated gene expression and induce leaf senescence. This study revealed one of the mechanisms underlying JA-induced leaf senescence: antagonistic interactions of the bHLH subgroup IIIe factors MYC2, MYC3, and MYC4 with the bHLH subgroup IIId factors bHLH03, bHLH13, bHLH14, and bHLH17. We showed that MYC2, MYC3, and MYC4 function redundantly to activate JA-induced leaf senescence. MYC2 binds to and activates the promoter of its target gene SAG29 (SENESCENCE-ASSOCIATED GENE29) to activate JA-induced leaf senescence. Interestingly, plants have evolved an elaborate feedback regulation mechanism to modulate JA-induced leaf senescence: The bHLH subgroup IIId factors (bHLH03, bHLH13, bHLH14, and bHLH17) bind to the promoter of SAG29 and repress its expression to attenuate MYC2/MYC3/MYC4-activated JA-induced leaf senescence. The antagonistic regulation by activators and repressors would mediate JA-induced leaf senescence at proper level suitable for plant survival in fluctuating environmental conditions.
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Affiliation(s)
- Tiancong Qi
- Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jiaojiao Wang
- Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Huang Huang
- Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Bei Liu
- Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Hua Gao
- Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yule Liu
- Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Susheng Song
- Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Daoxin Xie
- Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
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Sethi V, Raghuram B, Sinha AK, Chattopadhyay S. A mitogen-activated protein kinase cascade module, MKK3-MPK6 and MYC2, is involved in blue light-mediated seedling development in Arabidopsis. Plant Cell 2014; 26:3343-57. [PMID: 25139007 PMCID: PMC4371833 DOI: 10.1105/tpc.114.128702] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 07/18/2014] [Accepted: 08/03/2014] [Indexed: 05/20/2023]
Abstract
Mitogen-activated protein kinase (MAPK) pathways are involved in several signal transduction processes in eukaryotes. Light signal transduction pathways have been extensively studied in plants; however, the connection between MAPK and light signaling pathways is currently unknown. Here, we show that MKK3-MPK6 is activated by blue light in a MYC2-dependent manner. MPK6 physically interacts with and phosphorylates a basic helix-loop-helix transcription factor, MYC2, and is phosphorylated by a MAPK kinase, MKK3. Furthermore, MYC2 binds to the MPK6 promoter and regulates its expression in a feedback regulatory mechanism in blue light signaling. We present mutational and physiological studies that illustrate the function of the MKK3-MPK6-MYC2 module in Arabidopsis thaliana seedling development and provide a revised mechanistic view of photomorphogenesis.
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Affiliation(s)
- Vishmita Sethi
- National Institute of Plant Genome Research, New Delhi 110067, India
| | - Badmi Raghuram
- National Institute of Plant Genome Research, New Delhi 110067, India
| | | | - Sudip Chattopadhyay
- National Institute of Plant Genome Research, New Delhi 110067, India Department of Biotechnology, National Institute of Technology, Durgapur 713209, India
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24
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Antony L, van der Schoor F, Dalrymple SL, Isaacs JT. Androgen receptor (AR) suppresses normal human prostate epithelial cell proliferation via AR/β-catenin/TCF-4 complex inhibition of c-MYC transcription. Prostate 2014; 74:1118-31. [PMID: 24913829 PMCID: PMC4856018 DOI: 10.1002/pros.22828] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [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: 04/18/2014] [Accepted: 05/02/2014] [Indexed: 11/11/2022]
Abstract
INTRODUCTION Physiologic testosterone continuously stimulates prostate stromal cell secretion of paracrine growth factors (PGFs), which if unopposed would induce hyperplastic overgrowth of normal prostate epithelial cells (PrECs). METHODS Lentiviral shRNA stable knock down of c-MYC, β-catenin, or TCF-4 completely inhibits normal (i.e., non-transformed) human PrECs growth. c-MYC enhancer driven reporter expression and growth is inhibited by two chemically distinct molecules, which prevent β-catenin signaling either by blocking TCF-4 binding (i.e., toxoflavin) or by stimulating degradation (i.e., AVX939). Recombinant DKK1 protein at a dose, which inhibits activation of canonical Wnt signaling does not inhibit PrEC growth. Nuclear β-catenin translocation and PrEC growth is prevented by both lack of PGFs or Akt inhibitor-I. Growth inhibition induced by lack of PGFs, toxoflavin, or Akt inhibitor-I is overcome by constitutive c-MYC transcription. RESULTS In the presence of continuous PGF signaling, PrEC hyperplasia is prevented by androgen binding to AR suppressing c-MYC transcription, resulting in G0 arrest/terminal differentiation independent of Rb, p21, p27, FoxP3, or down regulation of growth factors receptors and instead involves androgen-induced formation of AR/β-catenin/TCF-4 complexes, which suppress c-MYC transcription. Such suppression does not occur when AR is mutated in its zinc-finger binding domain. DISCUSSION Proliferation of non-transformed human PrECs is dependent upon c-MYC transcription via formation/binding of β-catenin/TCF-4 complexes at both 5' and 3' c-MYC enhancers stimulated by Wnt-independent, PGF induced Akt signaling. In the presence of continuous PGF signaling, PrEC hyperplasia is prevented by androgen-induced formation of AR/β-catenin/TCF-4 complexes, which retains binding to 3' c-MYC enhancer, but now suppresses c-MYC transcription.
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Affiliation(s)
- Lizamma Antony
- Chemical Therapeutics Program and Prostate Cancer Program, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Maryland
- Department of Urology, The Brady Urological Institute, The Johns Hopkins School of Medicine, Baltimore, Maryland
- Correspondence to: Lizamma Antony, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, 1650 Orleans St., Baltimore, MD 21287.
| | - Freek van der Schoor
- Chemical Therapeutics Program and Prostate Cancer Program, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Maryland
- Department of Urology, The Brady Urological Institute, The Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Susan L. Dalrymple
- Chemical Therapeutics Program and Prostate Cancer Program, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Maryland
- Department of Urology, The Brady Urological Institute, The Johns Hopkins School of Medicine, Baltimore, Maryland
| | - John T. Isaacs
- Chemical Therapeutics Program and Prostate Cancer Program, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Maryland
- Department of Urology, The Brady Urological Institute, The Johns Hopkins School of Medicine, Baltimore, Maryland
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Kulyté A, Belarbi Y, Lorente-Cebrián S, Bambace C, Arner E, Daub CO, Hedén P, Rydén M, Mejhert N, Arner P. Additive effects of microRNAs and transcription factors on CCL2 production in human white adipose tissue. Diabetes 2014; 63:1248-58. [PMID: 24379347 DOI: 10.2337/db13-0702] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Adipose tissue inflammation is present in insulin-resistant conditions. We recently proposed a network of microRNAs (miRNAs) and transcription factors (TFs) regulating the production of the proinflammatory chemokine (C-C motif) ligand-2 (CCL2) in adipose tissue. We presently extended and further validated this network and investigated if the circuits controlling CCL2 can interact in human adipocytes and macrophages. The updated subnetwork predicted that miR-126/-193b/-92a control CCL2 production by several TFs, including v-ets erythroblastosis virus E26 oncogene homolog 1 (avian) (ETS1), MYC-associated factor X (MAX), and specificity protein 12 (SP1). This was confirmed in human adipocytes by the observation that gene silencing of ETS1, MAX, or SP1 attenuated CCL2 production. Combined gene silencing of ETS1 and MAX resulted in an additive reduction in CCL2 production. Moreover, overexpression of miR-126/-193b/-92a in different pairwise combinations reduced CCL2 secretion more efficiently than either miRNA alone. However, although effects on CCL2 secretion by co-overexpression of miR-92a/-193b and miR-92a/-126 were additive in adipocytes, the combination of miR-126/-193b was primarily additive in macrophages. Signals for miR-92a and -193b converged on the nuclear factor-κB pathway. In conclusion, TF and miRNA-mediated regulation of CCL2 production is additive and partly relayed by cell-specific networks in human adipose tissue that may be important for the development of insulin resistance/type 2 diabetes.
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Affiliation(s)
- Agné Kulyté
- Department of Medicine, Huddinge, Lipid Laboratory, Karolinska Institutet, Stockholm, Sweden
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Zhang X, Zhu Z, An F, Hao D, Li P, Song J, Yi C, Guo H. Jasmonate-activated MYC2 represses ETHYLENE INSENSITIVE3 activity to antagonize ethylene-promoted apical hook formation in Arabidopsis. Plant Cell 2014; 26:1105-17. [PMID: 24668749 PMCID: PMC4001372 DOI: 10.1105/tpc.113.122002] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 02/11/2014] [Accepted: 03/03/2014] [Indexed: 05/20/2023]
Abstract
The apical hook is an essential structure that enables epigeal plants to protrude through the soil. Arabidopsis thaliana HOOKLESS1 (HLS1) is reported to be a key regulator of hook development and a direct target gene of the ethylene (ET)-activated transcription factors ETHYLENE INSENSITIVE3 (EIN3) and its close homolog EIN3-Like1. Previous research has shown that the phytohormones jasmonate (JA) and ET antagonistically regulate apical hook development, although the underlying molecular mechanism is largely unknown. Here, we report that JA represses hook formation by reducing HLS1 expression. Our results further reveal that the JA-activated transcription factor MYC2 represses EIN3 function to reduce HLS1 expression through at least the following two layers of regulation: (1) MYC2 binds to the promoter of an F-box gene, EIN3 BINDING F-BOX PROTEIN1, to induce its expression and thus promote EIN3 degradation; and (2) MYC2 physically interacts with EIN3 and inhibits its DNA binding activity. Collectively, our findings shed light on the molecular mechanism underlying the antagonism between JA and ET during apical hook development and provide insight into the coaction of multiple phytohormones in the regulation of plant growth and development.
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Affiliation(s)
- Xing Zhang
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China
- Peking-Tsinghua Center for Life Sciences, Beijing 100871, China
| | - Ziqiang Zhu
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China
- College of Life Sciences, Nanjing Normal University, Nanjing 210023, China
| | - Fengying An
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China
- Peking-Tsinghua Center for Life Sciences, Beijing 100871, China
| | - Dongdong Hao
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China
- Peking-Tsinghua Center for Life Sciences, Beijing 100871, China
| | - Pengpeng Li
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China
| | - Jinghui Song
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China
| | - Chengqi Yi
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China
- Peking-Tsinghua Center for Life Sciences, Beijing 100871, China
- Synthetic and Functional Biomolecules Center, Peking University, Beijing 100871, China
| | - Hongwei Guo
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China
- Peking-Tsinghua Center for Life Sciences, Beijing 100871, China
- Address correspondence to
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Bernal-Mizrachi E, Kulkarni RN, Scott DK, Mauvais-Jarvis F, Stewart AF, Garcia-Ocaña A. Human β-cell proliferation and intracellular signaling part 2: still driving in the dark without a road map. Diabetes 2014; 63:819-31. [PMID: 24556859 PMCID: PMC3931400 DOI: 10.2337/db13-1146] [Citation(s) in RCA: 139] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Enhancing β-cell proliferation is a major goal for type 1 and type 2 diabetes research. Unraveling the network of β-cell intracellular signaling pathways that promote β-cell replication can provide the tools to address this important task. In a previous Perspectives in Diabetes article, we discussed what was known regarding several important intracellular signaling pathways in rodent β-cells, including the insulin receptor substrate/phosphatidylinositol-3 kinase/Akt (IRS-PI3K-Akt) pathways, glycogen synthase kinase-3 (GSK3) and mammalian target of rapamycin (mTOR) S6 kinase pathways, protein kinase Cζ (PKCζ) pathways, and their downstream cell-cycle molecular targets, and contrasted that ample knowledge to the small amount of complementary data on human β-cell intracellular signaling pathways. In this Perspectives, we summarize additional important information on signaling pathways activated by nutrients, such as glucose; growth factors, such as epidermal growth factor, platelet-derived growth factor, and Wnt; and hormones, such as leptin, estrogen, and progesterone, that are linked to rodent and human β-cell proliferation. With these two Perspectives, we attempt to construct a brief summary of knowledge for β-cell researchers on mitogenic signaling pathways and to emphasize how little is known regarding intracellular events linked to human β-cell replication. This is a critical aspect in the long-term goal of expanding human β-cells for the prevention and/or cure of type 1 and type 2 diabetes.
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Affiliation(s)
- Ernesto Bernal-Mizrachi
- Division of Metabolism, Endocrinology, and Diabetes, University of Michigan, and U.S. Department of Veterans Affairs Ann Arbor Healthcare System, Ann Arbor, MI
- Corresponding authors: Ernesto Bernal-Mizrachi, , and Adolfo Garcia-Ocaña,
| | - Rohit N. Kulkarni
- Islet Cell Biology and Regenerative Medicine, Joslin Diabetes Center, Harvard Medical School, Boston, MA
- Department of Medicine, Harvard Medical School, Boston, MA
| | - Donald K. Scott
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Franck Mauvais-Jarvis
- Division of Endocrinology and Metabolism, Tulane University School of Medicine and Health Sciences Center, New Orleans, LA
| | - Andrew F. Stewart
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Adolfo Garcia-Ocaña
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
- Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY
- Corresponding authors: Ernesto Bernal-Mizrachi, , and Adolfo Garcia-Ocaña,
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Song S, Huang H, Gao H, Wang J, Wu D, Liu X, Yang S, Zhai Q, Li C, Qi T, Xie D. Interaction between MYC2 and ETHYLENE INSENSITIVE3 modulates antagonism between jasmonate and ethylene signaling in Arabidopsis. Plant Cell 2014; 26:263-79. [PMID: 24399301 PMCID: PMC3963574 DOI: 10.1105/tpc.113.120394] [Citation(s) in RCA: 235] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 12/09/2013] [Accepted: 12/13/2013] [Indexed: 05/20/2023]
Abstract
Plants have evolved sophisticated mechanisms for integration of endogenous and exogenous signals to adapt to the changing environment. Both the phytohormones jasmonate (JA) and ethylene (ET) regulate plant growth, development, and defense. In addition to synergistic regulation of root hair development and resistance to necrotrophic fungi, JA and ET act antagonistically to regulate gene expression, apical hook curvature, and plant defense against insect attack. However, the molecular mechanism for such antagonism between JA and ET signaling remains unclear. Here, we demonstrate that interaction between the JA-activated transcription factor MYC2 and the ET-stabilized transcription factor ETHYLENE-INSENSITIVE3 (EIN3) modulates JA and ET signaling antagonism in Arabidopsis thaliana. MYC2 interacts with EIN3 to attenuate the transcriptional activity of EIN3 and repress ET-enhanced apical hook curvature. Conversely, EIN3 interacts with and represses MYC2 to inhibit JA-induced expression of wound-responsive genes and herbivory-inducible genes and to attenuate JA-regulated plant defense against generalist herbivores. Coordinated regulation of plant responses in both antagonistic and synergistic manners would help plants adapt to fluctuating environments.
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Affiliation(s)
- Susheng Song
- Tsinghua-Peking Center for Life Sciences, MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Huang Huang
- Tsinghua-Peking Center for Life Sciences, MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Hua Gao
- Tsinghua-Peking Center for Life Sciences, MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jiaojiao Wang
- Tsinghua-Peking Center for Life Sciences, MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Dewei Wu
- Tsinghua-Peking Center for Life Sciences, MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xili Liu
- Department of Plant Pathology, China Agricultural University, Beijing 100193, China
| | - Shuhua Yang
- College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Qingzhe Zhai
- State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Chuanyou Li
- State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Tiancong Qi
- Tsinghua-Peking Center for Life Sciences, MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Daoxin Xie
- Tsinghua-Peking Center for Life Sciences, MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Address correspondence to
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Sasaki-Sekimoto Y, Jikumaru Y, Obayashi T, Saito H, Masuda S, Kamiya Y, Ohta H, Shirasu K. Basic helix-loop-helix transcription factors JASMONATE-ASSOCIATED MYC2-LIKE1 (JAM1), JAM2, and JAM3 are negative regulators of jasmonate responses in Arabidopsis. Plant Physiol 2013; 163:291-304. [PMID: 23852442 PMCID: PMC3762649 DOI: 10.1104/pp.113.220129] [Citation(s) in RCA: 142] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 07/12/2013] [Indexed: 05/18/2023]
Abstract
Jasmonates regulate transcriptional reprogramming during growth, development, and defense responses. Jasmonoyl-isoleucine, an amino acid conjugate of jasmonic acid (JA), is perceived by the protein complex composed of the F-box protein CORONATINE INSENSITIVE1 (COI1) and JASMONATE ZIM DOMAIN (JAZ) proteins, leading to the ubiquitin-dependent degradation of JAZ proteins. This activates basic helix-loop-helix-type MYC transcription factors to regulate JA-responsive genes. Here, we show that the expression of genes encoding other basic helix-loop-helix transcription factors, JASMONATE ASSOCIATED MYC2-LIKE1 (JAM1), JAM2, and JAM3, is positively regulated in a COI1- and MYC2-dependent manner in Arabidopsis (Arabidopsis thaliana). However, contrary to myc2, the jam1jam2jam3 triple mutant exhibited shorter roots when treated with methyl jasmonate (MJ), indicating enhanced responsiveness to JA. Our genome-wide expression analyses revealed that key jasmonate metabolic genes as well as a set of genes encoding transcription factors that regulate the JA-responsive metabolic genes are negatively regulated by JAMs after MJ treatment. Consistently, loss of JAM genes resulted in higher accumulation of anthocyanin in MJ-treated plants as well as higher accumulation of JA and 12-hydroxyjasmonic acid in wounded plants. These results show that JAMs negatively regulate the JA responses in a manner that is mostly antagonistic to MYC2.
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Decressac M, Mattsson B, Weikop P, Lundblad M, Jakobsson J, Björklund A. TFEB-mediated autophagy rescues midbrain dopamine neurons from α-synuclein toxicity. Proc Natl Acad Sci U S A 2013; 110:E1817-26. [PMID: 23610405 PMCID: PMC3651458 DOI: 10.1073/pnas.1305623110] [Citation(s) in RCA: 537] [Impact Index Per Article: 48.8] [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] [Indexed: 12/22/2022] Open
Abstract
The aggregation of α-synuclein plays a major role in Parkinson disease (PD) pathogenesis. Recent evidence suggests that defects in the autophagy-mediated clearance of α-synuclein contribute to the progressive loss of nigral dopamine neurons. Using an in vivo model of α-synuclein toxicity, we show that the PD-like neurodegenerative changes induced by excess cellular levels of α-synuclein in nigral dopamine neurons are closely linked to a progressive decline in markers of lysosome function, accompanied by cytoplasmic retention of transcription factor EB (TFEB), a major transcriptional regulator of the autophagy-lysosome pathway. The changes in lysosomal function, observed in the rat model as well as in human PD midbrain, were reversed by overexpression of TFEB, which afforded robust neuroprotection via the clearance of α-synuclein oligomers, and were aggravated by microRNA-128-mediated repression of TFEB in both A9 and A10 dopamine neurons. Delayed activation of TFEB function through inhibition of mammalian target of rapamycin blocked α-synuclein induced neurodegeneration and further disease progression. The results provide a mechanistic link between α-synuclein toxicity and impaired TFEB function, and highlight TFEB as a key player in the induction of α-synuclein-induced toxicity and PD pathogenesis, thus identifying TFEB as a promising target for therapies aimed at neuroprotection and disease modification in PD.
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Affiliation(s)
- Mickael Decressac
- Department of Experimental Medical Sciences, Wallenberg Neuroscience Center, Lund University, 22184 Lund, Sweden; and
| | - Bengt Mattsson
- Department of Experimental Medical Sciences, Wallenberg Neuroscience Center, Lund University, 22184 Lund, Sweden; and
| | - Pia Weikop
- Laboratory of Neuropsychiatry, Rigshospitalet University Hospital, DK-2100 Copenhagen, Denmark
| | - Martin Lundblad
- Department of Experimental Medical Sciences, Wallenberg Neuroscience Center, Lund University, 22184 Lund, Sweden; and
| | - Johan Jakobsson
- Department of Experimental Medical Sciences, Wallenberg Neuroscience Center, Lund University, 22184 Lund, Sweden; and
| | - Anders Björklund
- Department of Experimental Medical Sciences, Wallenberg Neuroscience Center, Lund University, 22184 Lund, Sweden; and
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Beaulieu ME, McDuff FO, Bédard M, Montagne M, Lavigne P. Methods for the expression, purification, preparation, and biophysical characterization of constructs of the c-Myc and Max b-HLH-LZs. Methods Mol Biol 2013; 1012:7-20. [PMID: 24006055 DOI: 10.1007/978-1-62703-429-6_2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Specific heterodimerization and DNA binding by the b-HLH-LZ transcription factors c-Myc and Max is central to the activation and repression activities of c-Myc that lead to cell growth, proliferation, and tumorigenesis (Adhikary and Eilers, Nat Rev Mol Cell Biol 6:635-645, 2005; Eilers and Eisenman, Genes Dev 22:2755-2766, 2008; Grandori et al., Annu Rev Cell Dev Biol 16:653-699, 2000; Whitfield and Soucek, Cell Mol Life Sci 69:931-934, 2011). Although many c-Myc-interacting partner proteins are known to interact through their HLH domain (Adhikary and Eilers, Nat Rev Mol Cell Biol 6:635-645, 2005), current knowledge regarding the structure and the determinants of molecular recognition of these complexes is still very limited. Moreover, recent advances in the development and use of b-HLH-LZ dominant negatives (Soucek et al., Nature 455:679-683, 2008) and inhibitors of c-Myc interaction with its protein partners (Bidwell et al., J Control Release 135:2-10, 2009; Mustata et al., J Med Chem 52:1247-1250, 2009; Prochownik and Vogt, Genes Cancer 1:650-659, 2010) or DNA highlight the importance of efficient protocols to prepare such constructs and variants. Here, we provide methods to produce and purify high quantities of pure and untagged b-HLH-LZ constructs of c-Myc and Max as well as specific c-Myc/Max heterodimers for their biophysical and structural characterization by CD, NMR, or crystallography. Moreover, biochemical methods to analyze the homodimers and heterodimers as well as DNA binding of these constructs by native electrophoresis are presented. In addition to enable the investigation of the c-Myc/Max b-HLH-LZ complexes, the protocols described herein can be applied to the biochemical characterization of various mutants of either partner, as well as to ternary complexes with other partner proteins.
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Affiliation(s)
- Marie-Eve Beaulieu
- Département de Pharmacologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, QC, Canada
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Soggia A, Flosseau K, Ravassard P, Szinnai G, Scharfmann R, Guillemain G. Activation of the transcription factor carbohydrate-responsive element-binding protein by glucose leads to increased pancreatic beta cell differentiation in rats. Diabetologia 2012; 55:2713-2722. [PMID: 22760788 PMCID: PMC3433661 DOI: 10.1007/s00125-012-2623-0] [Citation(s) in RCA: 14] [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] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 05/17/2012] [Indexed: 01/05/2023]
Abstract
AIMS/HYPOTHESIS Pancreatic cell development is a tightly controlled process. Although information is available regarding the mesodermal signals that control pancreatic development, little is known about the role of environmental factors such as nutrients, including glucose, on pancreatic development. We previously showed that glucose and its metabolism through the hexosamine biosynthesis pathway (HBP) promote pancreatic endocrine cell differentiation. Here, we analysed the role of the transcription factor carbohydrate-responsive element-binding protein (ChREBP) in this process. This transcription factor is activated by glucose, and has been recently described as a target of the HBP. METHODS We used an in vitro bioassay in which pancreatic endocrine and exocrine cells develop from rat embryonic pancreas in a way that mimics in vivo pancreatic development. Using this model, gain-of-function and loss-of-function experiments were undertaken. RESULTS ChREBP was produced in the endocrine lineage during pancreatic development, its abundance increasing with differentiation. When rat embryonic pancreases were cultured in the presence of glucose or xylitol, the production of ChREBP targets was induced. Concomitantly, beta cell differentiation was enhanced. On the other hand, when embryonic pancreases were cultured with inhibitors decreasing ChREBP activity or an adenovirus producing a dominant-negative ChREBP, beta cell differentiation was reduced, indicating that ChREBP activity was necessary for proper beta cell differentiation. Interestingly, adenovirus producing a dominant-negative ChREBP also reduced the positive effect of N-acetylglucosamine, a substrate of the HBP acting on beta cell differentiation. CONCLUSIONS/INTERPRETATION Our work supports the idea that glucose, through the transcription factor ChREBP, controls beta cell differentiation from pancreatic progenitors.
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Affiliation(s)
- A Soggia
- INSERM U845, Research Center Growth and Signalling, Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine, Hôpital Necker, Paris, France
| | - K Flosseau
- INSERM U845, Research Center Growth and Signalling, Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine, Hôpital Necker, Paris, France
| | - P Ravassard
- CNRS - UMR 7225, CNRS - UMR 7225 Hôpital Pitié Salpêtrière, Paris, France
| | - G Szinnai
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - R Scharfmann
- INSERM U845, Research Center Growth and Signalling, Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine, Hôpital Necker, Paris, France
| | - G Guillemain
- INSERM U845, Research Center Growth and Signalling, Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine, Hôpital Necker, Paris, France.
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Petti AA, McIsaac RS, Ho-Shing O, Bussemaker HJ, Botstein D. Combinatorial control of diverse metabolic and physiological functions by transcriptional regulators of the yeast sulfur assimilation pathway. Mol Biol Cell 2012; 23:3008-24. [PMID: 22696679 PMCID: PMC3408426 DOI: 10.1091/mbc.e12-03-0233] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Revised: 06/04/2012] [Accepted: 06/06/2012] [Indexed: 01/03/2023] Open
Abstract
Methionine abundance affects diverse cellular functions, including cell division, redox homeostasis, survival under starvation, and oxidative stress response. Regulation of the methionine biosynthetic pathway involves three DNA-binding proteins-Met31p, Met32p, and Cbf1p. We hypothesized that there exists a "division of labor" among these proteins that facilitates coordination of methionine biosynthesis with diverse biological processes. To explore combinatorial control in this regulatory circuit, we deleted CBF1, MET31, and MET32 individually and in combination in a strain lacking methionine synthase. We followed genome-wide gene expression as these strains were starved for methionine. Using a combination of bioinformatic methods, we found that these regulators control genes involved in biological processes downstream of sulfur assimilation; many of these processes had not previously been documented as methionine dependent. We also found that the different factors have overlapping but distinct functions. In particular, Met31p and Met32p are important in regulating methionine metabolism, whereas p functions as a "generalist" transcription factor that is not specific to methionine metabolism. In addition, Met31p and Met32p appear to regulate iron-sulfur cluster biogenesis through direct and indirect mechanisms and have distinguishable target specificities. Finally, CBF1 deletion sometimes has the opposite effect on gene expression from MET31 and MET32 deletion.
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Affiliation(s)
- Allegra A. Petti
- The Lewis-Sigler Institute for Integrative Genomics, Columbia University, New York, NY 10027
| | - R. Scott McIsaac
- The Lewis-Sigler Institute for Integrative Genomics, Columbia University, New York, NY 10027
- Graduate Program in Quantitative and Computational Biology, Columbia University, New York, NY 10027
| | - Olivia Ho-Shing
- The Lewis-Sigler Institute for Integrative Genomics, Columbia University, New York, NY 10027
| | | | - David Botstein
- The Lewis-Sigler Institute for Integrative Genomics, Columbia University, New York, NY 10027
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
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Metukuri MR, Zhang P, Basantani MK, Chin C, Stamateris RE, Alonso LC, Takane KK, Gramignoli R, Strom SC, O’Doherty RM, Stewart AF, Vasavada RC, Garcia-Ocaña A, Scott DK. ChREBP mediates glucose-stimulated pancreatic β-cell proliferation. Diabetes 2012; 61:2004-15. [PMID: 22586588 PMCID: PMC3402328 DOI: 10.2337/db11-0802] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Glucose stimulates rodent and human β-cell replication, but the intracellular signaling mechanisms are poorly understood. Carbohydrate response element-binding protein (ChREBP) is a lipogenic glucose-sensing transcription factor with unknown functions in pancreatic β-cells. We tested the hypothesis that ChREBP is required for glucose-stimulated β-cell proliferation. The relative expression of ChREBP was determined in liver and β-cells using quantitative RT-PCR (qRT-PCR), immunoblotting, and immunohistochemistry. Loss- and gain-of-function studies were performed using small interfering RNA and genetic deletion of ChREBP and adenoviral overexpression of ChREBP in rodent and human β-cells. Proliferation was measured by 5-bromo-2'-deoxyuridine incorporation, [(3)H]thymidine incorporation, and fluorescence-activated cell sorter analysis. In addition, the expression of cell cycle regulatory genes was measured by qRT-PCR and immunoblotting. ChREBP expression was comparable with liver in mouse pancreata and in rat and human islets. Depletion of ChREBP decreased glucose-stimulated proliferation in β-cells isolated from ChREBP(-/-) mice, in INS-1-derived 832/13 cells, and in primary rat and human β-cells. Furthermore, depletion of ChREBP decreased the glucose-stimulated expression of cell cycle accelerators. Overexpression of ChREBP amplified glucose-stimulated proliferation in rat and human β-cells, with concomitant increases in cyclin gene expression. In conclusion, ChREBP mediates glucose-stimulated proliferation in pancreatic β-cells.
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Affiliation(s)
- Mallikarjuna R. Metukuri
- Department of Medicine, Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
| | - Pili Zhang
- Department of Medicine, Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Mahesh K. Basantani
- Department of Medicine, Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Connie Chin
- Department of Medicine, Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Rachel E. Stamateris
- Department of Medicine, Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Laura C. Alonso
- Department of Medicine, Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Karen K. Takane
- Department of Medicine, Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Roberto Gramignoli
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Stephen C. Strom
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Robert M. O’Doherty
- Department of Medicine, Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Andrew F. Stewart
- Department of Medicine, Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Rupangi C. Vasavada
- Department of Medicine, Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Adolfo Garcia-Ocaña
- Department of Medicine, Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Donald K. Scott
- Department of Medicine, Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania
- Corresponding author: Donald K. Scott,
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Wernicke CM, Richter GHS, Beinvogl BC, Plehm S, Schlitter AM, Bandapalli OR, Prazeres da Costa O, Hattenhorst UE, Volkmer I, Staege MS, Esposito I, Burdach S, Grunewald TGP. MondoA is highly overexpressed in acute lymphoblastic leukemia cells and modulates their metabolism, differentiation and survival. Leuk Res 2012; 36:1185-92. [PMID: 22748921 DOI: 10.1016/j.leukres.2012.05.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Revised: 05/17/2012] [Accepted: 05/21/2012] [Indexed: 01/28/2023]
Abstract
Acute lymphoblastic leukemia (ALL) is the most common childhood cancer. To identify novel candidates for targeted therapy, we performed a comprehensive transcriptome analysis identifying MondoA (MLXIP) - a transcription factor regulating glycolysis - to be overexpressed in ALL compared to normal tissues. Using microarray-profiling, gene-set enrichment analysis, RNA interference and functional assays we show that MondoA overexpression increases glucose catabolism and maintains a more immature phenotype, which is associated with enhanced survival and clonogenicity of leukemia cells. These data point to an important contribution of MondoA to leukemia aggressiveness and make MondoA a potential candidate for targeted treatment of ALL.
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Affiliation(s)
- Caroline M Wernicke
- Children's Cancer Research and Roman Herzog Comprehensive Cancer Center, Laboratory of Functional Genomics and Transplantation Biology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
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36
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37
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Iwasaki H, Naka A, Iida KT, Nakagawa Y, Matsuzaka T, Ishii KA, Kobayashi K, Takahashi A, Yatoh S, Yahagi N, Sone H, Suzuki H, Yamada N, Shimano H. TFE3 regulates muscle metabolic gene expression, increases glycogen stores, and enhances insulin sensitivity in mice. Am J Physiol Endocrinol Metab 2012; 302:E896-902. [PMID: 22297304 DOI: 10.1152/ajpendo.00204.2011] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The role of transcription factor E3 (TFE3), a bHLH transcription factor, in immunology and cancer has been well characterized. Recently, we reported that TFE3 activates hepatic IRS-2 and hexokinase, participates in insulin signaling, and ameliorates diabetes. However, the effects of TFE3 in other organs are poorly understood. Herein, we examined the effects of TFE3 on skeletal muscle, an important organ involved in glucose metabolism. We generated transgenic mice that selectively express TFE3 in skeletal muscles. These mice exhibit a slight acceleration in growth prior to adulthood as well as a progressive increase in muscle mass. In TFE3 transgenic muscle, glycogen stores were more than twofold than in wild-type mice, and this was associated with an upregulation of genes involved in glucose metabolism, specifically glucose transporter 4, hexokinase II, and glycogen synthase. Consequently, exercise endurance capacity was enhanced in this transgenic model. Furthermore, insulin sensitivity was enhanced in transgenic mice and exhibited better improvement after 4 wk of exercise training, which was associated with increased IRS-2 expression. The effects of TFE3 on glucose metabolism in skeletal muscle were different from that in the liver, although they did, in part, overlap. The potential role of TFE3 in regulating metabolic genes and glucose metabolism within skeletal muscle suggests that it may be used for treating metabolic diseases as well as increasing endurance in sport.
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Affiliation(s)
- Hitoshi Iwasaki
- Department of Internal Medicine, Faculty of Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Japan
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Maruta T, Inoue T, Tamoi M, Yabuta Y, Yoshimura K, Ishikawa T, Shigeoka S. Arabidopsis NADPH oxidases, AtrbohD and AtrbohF, are essential for jasmonic acid-induced expression of genes regulated by MYC2 transcription factor. Plant Sci 2011; 180:655-60. [PMID: 21421415 DOI: 10.1016/j.plantsci.2011.01.014] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2010] [Revised: 01/15/2011] [Accepted: 01/19/2011] [Indexed: 05/06/2023]
Abstract
To clarify genetically the involvement of two Arabidopsis NADPH oxidases (AtrbohD and AtrbohF) in the jasmonic acid (JA) signaling pathway, we characterized single knockout mutants lacking either Atrboh. The accumulation of reactive oxygen species (ROS) and expression of the genes regulated by MYC2, a transcription factor involved in the JA-evoked response, were significantly suppressed by treatment with methyl JA (MeJA) in both mutants. Further experiments using knockout mutants lacking CORONATINE-INSENSITIVE1 (COI1), a master regulator of the JA-evoked response, and MYC2 indicated a possibility that the production of ROS via Atrbohs depends on the function of COI1, but not MYC2.
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Affiliation(s)
- Takanori Maruta
- Department of Advanced Bioscience, Faculty of Agriculture, Kinki University, Nakamachi, Nara 631-8505, Japan
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39
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Nakagawa Y, Shimano H. [Transcription factor, TFE3 improves metabolic syndrome]. Nihon Rinsho 2011; 69 Suppl 1:790-796. [PMID: 21766698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Affiliation(s)
- Yoshimi Nakagawa
- Department of Internal Medicine (Endocrinology and Metabolism), Graduate School of Comprehensive Human Sciences, University of Tsukuba
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40
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Iizuka K. [ChREBP and other transcription factors]. Nihon Rinsho 2011; 69 Suppl 1:275-278. [PMID: 21766609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Affiliation(s)
- Katsumi Iizuka
- Department of Diabetes and Metabolism, Center for Nutritional Support and Infection Control, Gifu University Hospital
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41
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Makino Y, Isoe T, Haneda M. [HIF-1 in diabetic nephropathy]. Nihon Jinzo Gakkai Shi 2011; 53:1006-1009. [PMID: 22073864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
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42
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Gangappa SN, Chattopadhyay S. MYC2, a bHLH transcription factor, modulates the adult phenotype of SPA1. Plant Signal Behav 2010; 5:1650-2. [PMID: 21512327 PMCID: PMC3115125 DOI: 10.4161/psb.5.12.13981] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [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: 10/20/2010] [Accepted: 10/20/2010] [Indexed: 05/17/2023]
Abstract
MYC2 and SPA1 are two key regulatory proteins that negatively regulate light-controlled Arabidopsis seedling development. We have recently demonstrated the genetic and molecular relationships of MYC2 and SPA1 in light and JA (jasmonic acid) signaling pathways. Here, we have further shown the genetic interactions between these two proteins in flowering time and lateral root development.
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Affiliation(s)
- Sreeramaiah N Gangappa
- National Institute of Plant Genome Research; Aruna Asaf Ali Marg; New Delhi, Haryana, India
| | - Sudip Chattopadhyay
- National Institute of Plant Genome Research; Aruna Asaf Ali Marg; New Delhi, Haryana, India
- Department of Biotechnology; National Institute of Technology; Durgapur, West Bengal, India
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Abstract
Steatosis is an accumulation of triglycerides in the liver. Although an excessive availability of plasma fatty acids is an important determinant of steatosis, lipid synthesis from glucose (lipogenesis) is now also considered as an important contributing factor. Lipogenesis is an insulin- and glucose-dependent process that is under the control of specific transcription factors, sterol regulatory element binding protein 1c (SREBP-1c), activated by insulin and carbohydrate response element binding protein (ChREBP) activated by glucose. Insulin induces the maturation of SREBP-1c by a proteolytic mechanism initiated in the endoplasmic reticulum (ER). SREBP-1c in turn activates glycolytic gene expression, allowing glucose metabolism, and lipogenic genes in conjunction with ChREBP. Lipogenesis activation in the liver of obese markedly insulin-resistant steatotic rodents is then paradoxical. Recent data suggest that the activation of SREBP-1c and thus of lipogenesis is secondary in the steatotic liver to an ER stress. The ER stress activates the cleavage of SREBP-1c independent of insulin, thus explaining the paradoxical stimulation of lipogenesis in an insulin-resistant liver. Inhibition of the ER stress in obese rodents decreases SREBP-1c activation and lipogenesis and improves markedly hepatic steatosis and insulin sensitivity. ER is thus a new partner in steatosis and metabolic syndrome which is worth considering as a potential therapeutic target.
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Affiliation(s)
- P Ferré
- INSERM, UMR-S 872, Centre de Recherches des Cordeliers and Université Pierre et Marie Curie-Paris, Paris, France
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Zhao LF, Iwasaki Y, Zhe W, Nishiyama M, Taguchi T, Tsugita M, Kambayashi M, Hashimoto K, Terada Y. Hormonal regulation of acetyl-CoA carboxylase isoenzyme gene transcription. Endocr J 2010; 57:317-24. [PMID: 20139635 DOI: 10.1507/endocrj.k09e-298] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Both glucocorticoid and insulin are known to have an anabolic effect on lipogenesis. Acetyl-CoA, an intermediate product of glycolysis, is supplied for fatty acid synthesis when carbohydrate intake is sufficient. Acetyl-CoA carboxylase (ACC), consisting of two isoenzymes ACC1 and ACC2, mediates the conversion from acetyl-CoA to malonyl-CoA, and thus plays a key role for the regulation of lipogenesis. In this study, we surveyed the effects of glucocorticoid and insulin on the transcriptional activity of the alternative promoters of ACCs (PI-PIII for ACC1, and PI and PII for ACC2) using the HepG2 human hepatocyte cell line in vitro. We also examined the roles of the insulin and/or glucose-regulated transcriptional factor(s) such as SREBP1c, LXRalpha/beta, and ChREBP on each promoter of the ACC genes. We found that both insulin and glucocorticoid had potent positive effects on all the promoters examined, and additive effects of both hormones were recognized in ACC1 PI and ACC2 PI. Furthermore, a representative insulin-responsive transcription factor SREBP1c showed significant stimulatory effects on all the promoters of ACC genes, among which those on ACC1 PIII and ACC2 PI were most prominent. On the other hand, the effect of LXRalpha was rather selective; it showed a marked stimulatory effect only on ACC1 PII. LXRbeta and ChREBP had minimal, if any, effects on some of the promoters. Altogether, our data suggest that insulin and glucocorticoid have positive effects on both ACC1 and ACC2 gene transcription. SREBP1c might be a master regulator of the expression of both genes regardless of the promoter utilized, whereas LXRalpha seems to play a promoter-specific role. Since ACC1 facilitates lipogenesis by stimulating fatty acid synthesis and ACC2 inhibits lipolysis, both insulin and glucocorticoid seem to play an important role in the pathogenesis of obesity and/or hepatic steatosis.
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Affiliation(s)
- Li Feng Zhao
- Department of Endocrinology, Metabolism, and Nephrology, Kochi Medical School, Kochi University, Nankoku, Japan
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Abstract
Myc is the most frequently deregulated oncogene in human tumors. The protein belongs to the Myc/Max/Mxd network of transcriptional regulators important for cell growth, proliferation, differentiation, and apoptosis. The ratio between Mnt/Max and c-Myc/Max on the 5'-CACGTG-3' E-box sequence at shared target genes is of great importance for cell cycle progression and arrest. Serum stimulation of quiescent cells results in phosphorylation of Mnt and disruption of the critical Mnt-mSin3-HDAC1 interaction. This in turn leads to increased expression of the Myc/Mnt target gene cyclin D2. It is therefore possible that Myc function relies on its ability to overcome transcriptional repression by Mnt and that relief of Mnt-mediated transcriptional repression is of greater importance for regulation of target genes than the sole activation by Myc. In addition, Mnt has many features of a tumor suppressor and may thus be nonfunctional or inactivated in human tumors. In summary, accumulating evidence supports the model of Mnt as the key regulator of the network in vivo.
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Affiliation(s)
- Therese Wahlström
- Department of Microbiology, Tumor, and Cell Biology (MTC), Karolinska Institutet, SE-171 77 Stockholm, Sweden
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46
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Huo M, Yang JC, Guan YF. [The role of chREBP in regulating lipid metabolism in the liver]. Sheng Li Ke Xue Jin Zhan 2009; 40:337-340. [PMID: 21417035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
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47
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Matsuoka Y, Uehara N, Tsubura A. hnRNP U interacts with the c-Myc-Max complex on the E-box promoter region inducing the ornithine decarboxylase gene. Oncol Rep 2009; 22:249-255. [PMID: 19578763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023] Open
Abstract
The promoter of the ornithine decarboxylase (ODC) gene contains two E-boxes, which are critical sites for transcriptional activation by the binding of c-Myc-Max heterodimers. We have identified heterogeneous nuclear ribonuclear protein U (hnRNP U) as a component of the complex formed on the E-box-containing promoter region of the ODC gene by using DNA-affinity chromatography, immunoprecipitation and chromatin immunoprecipitation assays. The N-terminal domain of hnRNP U was responsible for the association with c-Myc-Max complex. Down-regulation of hnRNP U with RNA interference blocked the induction of the ODC gene and cell growth by serum stimulation, suggesting that hnRNP U is a coactivator of the c-Myc-Max complex and essential for cell proliferation. Electrophoretic mobility-shift assays revealed that the segment between the two E-boxes in the promoter is the primary binding site of hnRNP U. The putative binding sequence was narrowed-down to a 13-nucleotide segment by comparing the sequence between the E-boxes with the binding sites of hnRNP U, which were recently identified in the promoter of Bmal1, a core component of the circadian molecular oscillator. These findings increase our knowledge of how the c-Myc-Max complex exerts its transcriptional regulatory role and suggest that hnRNP U may be a coactivator of this transcriptional activator complex.
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Affiliation(s)
- Yoichiro Matsuoka
- Second Department of Pathology, Kansai Medical University, Osaka 570-8506, Japan.
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48
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Abstract
Excess carbohydrate intake leads to fat accumulation and insulin resistance. Glucose and insulin coordinately regulate de novo lipogenesis from glucose in the liver, and insulin activates several transcription factors including SREBP1c and LXR, while those activated by glucose remain unknown. Recently, a carbohydrate response element binding protein (ChREBP), which binds to the carbohydrate response element (ChoRE) in the promoter of rat liver type pyruvate kinase (LPK), has been identified. The target genes of ChREBP are involved in glycolysis, lipogenesis, and gluconeogenesis. Although the regulation of ChREBP remains unknown in detail, the transactivity of ChREBP is partly regulated by a phosphorylation/dephosphorylation mechanism. During fasting, protein kinase A and AMP-activated protein kinase phosphorylate ChREBP and inactivate its transactivity. During feeding, xylulose-5-phosphate in the hexose monophosphate pathway activates protein phosphatase 2A, which dephosphorylates ChREBP and activates its transactivity. ChREBP controls 50% of hepatic lipogenesis by regulating glycolytic and lipogenic gene expression. In ChREBP (-/-) mice, liver triglyceride content is decreased and liver glycogen content is increased compared to wild-type mice. These results indicate that ChREBP can regulate metabolic gene expression to convert excess carbohydrate into triglyceride rather than glycogen. Furthermore, complete inhibition of ChREBP in ob/ob mice reduces the effects of the metabolic syndrome such as obesity, fatty liver, and glucose intolerance. Thus, further clarification of the physiological role of ChREBP may be useful in developing treatments for the metabolic syndrome.
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Affiliation(s)
- Katsumi Iizuka
- Laboratory of Medical Genomics, the Institute for Molecular and Cellular Regulation, Gunma University, Maebashi-shi, Japan.
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Abstract
PURPOSE OF REVIEW The liver is responsible for the conversion of excess dietary carbohydrates into fatty acids, through de-novo lipogenesis. A clear understanding of the control of lipogenesis is crucial since excess fatty acids leads to hepatic steatosis and associated metabolic diseases. The transcription factor sterol regulatory element binding protein 1c and the nuclear receptor liver X receptor are implicated in the insulin-mediated induction of lipogenic genes. Recently, the transcription factor carbohydrate responsive element binding protein has emerged as the hepatic glucose sensor required for the induction of lipogenic genes in response to glucose. RECENT FINDINGS We have recently demonstrated that the liver-specific inhibition of carbohydrate responsive element binding protein decreases the rate of lipogenesis and improves hepatic steatosis and insulin resistance in obese ob/ob mice. These results suggest that carbohydrate responsive element binding protein is a potential therapeutic target, and an accurate knowledge of the mechanisms involved in regulating its expression or activation is needed for the development of pharmacological approaches for the treatment of metabolic diseases. Recent studies report that carbohydrate responsive element binding protein is regulated at the transcriptional level by glucose and by liver X receptor but that posttranslational modifications are needed for carbohydrate responsive element binding protein to become active. SUMMARY Here we review some of the studies that provided a better understanding of the role and regulation of the newly identified transcription factor carbohydrate responsive element binding protein in lipid homeostasis.
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Affiliation(s)
- Pierre-Damien Denechaud
- Cochin Institute, Department of Endocrinology, Metabolism and Cancer, Paris Descartes University, CNRS (UMR 8104), Paris, France
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Collier JJ, Zhang P, Pedersen KB, Burke SJ, Haycock JW, Scott DK. c-Myc and ChREBP regulate glucose-mediated expression of the L-type pyruvate kinase gene in INS-1-derived 832/13 cells. Am J Physiol Endocrinol Metab 2007; 293:E48-56. [PMID: 17341548 DOI: 10.1152/ajpendo.00357.2006] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Increased glucose flux generates metabolic signals that control transcriptional programs through poorly understood mechanisms. Previously, we demonstrated a necessity in hepatocytes for c-Myc in the regulation of a prototypical glucose-responsive gene, L-type pyruvate kinase (L-PK) (Collier JJ, Doan TT, Daniels MC, Schurr JR, Kolls JK, Scott DK. J Biol Chem 278: 6588-6595, 2003). Pancreatic beta-cells have many features in common with hepatocytes with respect to glucose-regulated gene expression, and in the present study we determined whether c-Myc was required for the L-PK glucose response in insulin-secreting (INS-1)-derived 832/13 cells. Glucose increased c-Myc abundance and association with its heterodimer partner, Max. Manipulations that prevented the formation of a functional c-Myc/Max heterodimer reduced the expression of the L-PK gene. In addition, glucose augmented the binding of carbohydrate response element binding protein (ChREBP), c-Myc, and Max to the promoter of the L-PK gene in situ. The transactivation of ChREBP, but not of c-Myc, was dependent on high glucose concentrations in the contexts of either the L-PK promoter or a heterologous promoter. The glucose-mediated transactivation of ChREBP was independent of mutations that alter phosphorylation sites thought to regulate the cellular location of ChREBP. We conclude that maximal glucose-induced expression of the L-PK gene in INS-1-derived 832/13 cells involves increased c-Myc abundance, recruitment of c-Myc, Max, and ChREBP to the promoter, and a glucose-stimulated increase in ChREBP transactivation.
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Affiliation(s)
- J Jason Collier
- Division of Endocrinology and Metabolism, University of Pittsburgh School of Medicine, E1147 BST, 200 Lothrop St., Pittsburgh, PA 15261, USA
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