1
|
Sionov RV, Ahdut-HaCohen R. A Supportive Role of Mesenchymal Stem Cells on Insulin-Producing Langerhans Islets with a Specific Emphasis on The Secretome. Biomedicines 2023; 11:2558. [PMID: 37761001 PMCID: PMC10527322 DOI: 10.3390/biomedicines11092558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 09/06/2023] [Accepted: 09/14/2023] [Indexed: 09/29/2023] Open
Abstract
Type 1 Diabetes (T1D) is a chronic autoimmune disease characterized by a gradual destruction of insulin-producing β-cells in the endocrine pancreas due to innate and specific immune responses, leading to impaired glucose homeostasis. T1D patients usually require regular insulin injections after meals to maintain normal serum glucose levels. In severe cases, pancreas or Langerhans islet transplantation can assist in reaching a sufficient β-mass to normalize glucose homeostasis. The latter procedure is limited because of low donor availability, high islet loss, and immune rejection. There is still a need to develop new technologies to improve islet survival and implantation and to keep the islets functional. Mesenchymal stem cells (MSCs) are multipotent non-hematopoietic progenitor cells with high plasticity that can support human pancreatic islet function both in vitro and in vivo and islet co-transplantation with MSCs is more effective than islet transplantation alone in attenuating diabetes progression. The beneficial effect of MSCs on islet function is due to a combined effect on angiogenesis, suppression of immune responses, and secretion of growth factors essential for islet survival and function. In this review, various aspects of MSCs related to islet function and diabetes are described.
Collapse
Affiliation(s)
- Ronit Vogt Sionov
- The Institute of Biomedical and Oral Research (IBOR), Faculty of Dental Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Ronit Ahdut-HaCohen
- Department of Medical Neurobiology, Institute of Medical Research, Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel;
- Department of Science, The David Yellin Academic College of Education, Jerusalem 9103501, Israel
| |
Collapse
|
2
|
Kutpruek S, Suksri K, Maneethorn P, Semprasert N, Yenchitsomanus PT, Kooptiwut S. Imatinib prevents dexamethasone-induced pancreatic β-cell apoptosis via decreased TRAIL and DR5. J Cell Biochem 2023; 124:1309-1323. [PMID: 37555250 DOI: 10.1002/jcb.30450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 07/04/2023] [Accepted: 07/07/2023] [Indexed: 08/10/2023]
Abstract
Prolonged administration of dexamethasone, a potent anti-inflammatory drug, can lead to steroid-induced diabetes. Imatinib, a medication commonly prescribed for chronic myeloid leukemia (CML), has been shown to improve diabetes in CML patients. Our recent study demonstrated that dexamethasone induces pancreatic β-cell apoptosis by upregulating the expression of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and its receptor, death receptor 5 (DR5). We hypothesized that imatinib may protect against dexamethasone-induced pancreatic β-cell apoptosis by reducing the expression of TRAIL and DR5, thereby favorably modulating downstream effectors in apoptotic pathways. We test this hypothesis by assessing the effects of imatinib on dexamethasone-induced apoptosis in rat insulinoma cell line cells. As anticipated, dexamethasone treatment led to increased TRAIL and DR5 expression, as well as an elevation in superoxide production. Conversely, expression of the TRAIL decoy receptor (DcR1) was decreased. Moreover, key effectors in the extrinsic and intrinsic apoptosis pathways, such as B-cell lymphoma 2 (BCL-2) associated X (BAX), nuclear factor kappa B (NF-κb), P73, caspase 8, and caspase 9, were upregulated, while the antiapoptotic protein BCL-2 was downregulated. Interestingly and importantly, imatinib at a concentration of 10 µM reversed the effect of dexamethasone on TRAIL, DR5, DcR1, superoxide production, BAX, BCL-2, NF-κB, P73, caspase 3, caspase 8, and caspase 9. Similar effects of imatinib on dexamethasone-induced TRAIL and DR5 expression were also observed in isolated mouse islets. Taken together, our findings suggest that imatinib protects against dexamethasone-induced pancreatic β-cell apoptosis by reducing TRAIL and DR5 expression and modulating downstream effectors in the extrinsic and intrinsic apoptosis pathways.
Collapse
Affiliation(s)
- Suchanoot Kutpruek
- Department of Physiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Kanchana Suksri
- Department of Physiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Petcharee Maneethorn
- Department of Physiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Namoiy Semprasert
- Department of Physiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Pa-Thai Yenchitsomanus
- Research Department, Division of Molecular Medicine, Mahidol University, Bangkok, Thailand
| | - Suwattanee Kooptiwut
- Department of Physiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| |
Collapse
|
3
|
Zhu Y, Xu N, Wu S, Luan Y, Ke H, Wu L, Li Y, Lu Y, Xing X, Tian N, Liu Q, Tong L, Hu L, Ji Y, Chen Z, Zhang P, Tong X. MEK1-dependent MondoA phosphorylation regulates glucose uptake in response to ketone bodies in colorectal cancer cells. Cancer Sci 2023; 114:961-975. [PMID: 36398713 PMCID: PMC9986092 DOI: 10.1111/cas.15667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 11/06/2022] [Accepted: 11/15/2022] [Indexed: 11/19/2022] Open
Abstract
The Mondo family transcription factor MondoA plays a pivotal role in sensing metabolites, such as glucose, glutamine, and lactic acid, to regulate glucose metabolism and cell proliferation. Ketone bodies are important signals for reducing glucose uptake. However, it is unclear whether MondoA functions in ketone body-regulated glucose transport. Here we reported that ketone bodies promoted MondoA nuclear translocation and binding to the promoter of its target gene TXNIP. Ketone bodies reduced glucose uptake, increased apoptosis and decreased proliferation of colorectal cancer cells, which was impeded by MondoA knockdown. Moreover, we identified MEK1 as a novel component of the MondoA protein complex using a proteomic approach. Mechanistically, MEK1 interacted with MondoA and enhanced tyrosine 222, but not serine or threonine, phosphorylation of MondoA, inhibiting MondoA nuclear translocation and transcriptional activity. Ketone bodies decreased MEK1-dependent MondoA phosphorylation by blocking MondoA and MEK1 interaction, leading to MondoA nuclear translocation, TXNIP transcription, and inhibition of glucose uptake. Therefore, our study not only demonstrated that ketone bodies reduce glucose uptake, promote apoptosis, and inhibit cell proliferation in colorectal cancer cells by regulating MondoA phosphorylation but also identified MEK1-dependent phosphorylation as a new mechanism to manipulate MondoA activity.
Collapse
Affiliation(s)
- Yemin Zhu
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Nannan Xu
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Siming Wu
- Department of Clinical Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yu Luan
- Department of Clinical Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Huiyi Ke
- Department of Clinical Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lifang Wu
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yakui Li
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ying Lu
- Department of Biochemistry and Molecular Biology of School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Xindan Xing
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Na Tian
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China
| | - Qi Liu
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lingfeng Tong
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lei Hu
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yingning Ji
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhangbing Chen
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ping Zhang
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xuemei Tong
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| |
Collapse
|
4
|
Li M, Zhang J, Yang G, Zhang J, Han M, Zhang Y, Liu Y. Effects of Anterior Pituitary Adenomas' Hormones on Glucose Metabolism and Its Clinical Implications. Diabetes Metab Syndr Obes 2023; 16:409-424. [PMID: 36816815 PMCID: PMC9937076 DOI: 10.2147/dmso.s397445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 02/02/2023] [Indexed: 02/17/2023] Open
Abstract
Pituitary adenomas have recently become more common and their incidence is increasing yearly. Functional pituitary tumors commonly secrete prolactin, growth hormones, and adrenocorticotropic hormones, which cause diseases such as prolactinoma, acromegaly, and Cushing's disease, but rarely secrete luteinizing, follicle-stimulating, thyroid-stimulating, and melanocyte-stimulating hormones. In addition to the typical clinical manifestations of functional pituitary tumors caused by excessive hormone levels, some pituitary tumors are also accompanied by abnormal glucose metabolism. The effects of these seven hormones on glucose metabolism are important for the treatment of diabetes secondary to pituitary tumors. This review focuses on the effects of hormones on glucose metabolism, providing important clues for the diagnosis and treatment of related diseases.
Collapse
Affiliation(s)
- Mengnan Li
- Department of Endocrinology, First Hospital of Shanxi Medical University, Taiyuan, People’s Republic of China
- First Clinical Medical College, Shanxi Medical University, Taiyuan, People’s Republic of China
| | - Jian Zhang
- Department of Endocrinology, First Hospital of Shanxi Medical University, Taiyuan, People’s Republic of China
- First Clinical Medical College, Shanxi Medical University, Taiyuan, People’s Republic of China
| | - Guimei Yang
- Department of Endocrinology, First Hospital of Shanxi Medical University, Taiyuan, People’s Republic of China
- First Clinical Medical College, Shanxi Medical University, Taiyuan, People’s Republic of China
| | - Jiaxin Zhang
- Department of Endocrinology, First Hospital of Shanxi Medical University, Taiyuan, People’s Republic of China
- First Clinical Medical College, Shanxi Medical University, Taiyuan, People’s Republic of China
| | - Minmin Han
- Department of Endocrinology, First Hospital of Shanxi Medical University, Taiyuan, People’s Republic of China
- First Clinical Medical College, Shanxi Medical University, Taiyuan, People’s Republic of China
| | - Yi Zhang
- Department of Pharmacology, Shanxi Medical University, Taiyuan, People’s Republic of China
- Correspondence: Yi Zhang, Department of Pharmacology, Shanxi Medical University, Taiyuan, People’s Republic of China, Email
| | - Yunfeng Liu
- Department of Endocrinology, First Hospital of Shanxi Medical University, Taiyuan, People’s Republic of China
- Yunfeng Liu, Department of Endocrinology, First Hospital of Shanxi Medical University, Taiyuan, People’s Republic of China, Tel +86 18703416196, Email
| |
Collapse
|
5
|
Jiang N, Liu J, Guan C, Ma C, An J, Tang X. Thioredoxin-interacting protein: A new therapeutic target in bone metabolism disorders? Front Immunol 2022; 13:955128. [PMID: 36059548 PMCID: PMC9428757 DOI: 10.3389/fimmu.2022.955128] [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] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 07/28/2022] [Indexed: 12/05/2022] Open
Abstract
Target identification is essential for developing novel therapeutic strategies in diseases. Thioredoxin-interacting protein (TXNIP), also known as thioredoxin-binding protein-2, is a member of the α-arrestin protein family and is regulated by several cellular stress factors. TXNIP overexpression coupled with thioredoxin inhibits its antioxidant functions, thereby increasing oxidative stress. TXNIP is directly involved in inflammatory activation by interacting with Nod-like receptor protein 3 inflammasome. Bone metabolic disorders are associated with aging, oxidative stress, and inflammation. They are characterized by an imbalance between bone formation involving osteoblasts and bone resorption by osteoclasts, and by chondrocyte destruction. The role of TXNIP in bone metabolic diseases has been extensively investigated. Here, we discuss the roles of TXNIP in the regulatory mechanisms of transcription and protein levels and summarize its involvement in bone metabolic disorders such as osteoporosis, osteoarthritis, and rheumatoid arthritis. TXNIP is expressed in osteoblasts, osteoclasts, and chondrocytes and affects the differentiation and functioning of skeletal cells through both redox-dependent and -independent regulatory mechanisms. Therefore, TXNIP is a potential regulatory and functional factor in bone metabolism and a possible new target for the treatment of bone metabolism-related diseases.
Collapse
Affiliation(s)
- Na Jiang
- The First Clinical Medical College of Lanzhou University, Lanzhou, China
| | - Jinjin Liu
- The First Clinical Medical College of Lanzhou University, Lanzhou, China
- Department of Endocrinology, The First Hospital of Lanzhou University, Lanzhou, China
| | - Conghui Guan
- The First Clinical Medical College of Lanzhou University, Lanzhou, China
- Department of Endocrinology, The First Hospital of Lanzhou University, Lanzhou, China
| | - Chengxu Ma
- Department of Endocrinology, The First Hospital of Lanzhou University, Lanzhou, China
| | - Jinyang An
- The First Clinical Medical College of Lanzhou University, Lanzhou, China
| | - Xulei Tang
- The First Clinical Medical College of Lanzhou University, Lanzhou, China
- Department of Endocrinology, The First Hospital of Lanzhou University, Lanzhou, China
- *Correspondence: Xulei Tang,
| |
Collapse
|
6
|
Abstract
Prolonged excess of glucocorticoids (GCs) has adverse systemic effects leading to significant morbidities and an increase in mortality. Metabolic alterations associated with the high level of the GCs are key risk factors for the poor outcome. These include GCs causing excess gluconeogenesis via upregulation of key enzymes in the liver, a reduction of insulin sensitivity in skeletal muscle, liver and adipose tissue by inhibiting the insulin receptor signalling pathway, and inhibition of insulin secretion in beta cells leading to dysregulated glucose metabolism. In addition, chronic GC exposure leads to an increase in visceral adipose tissue, as well as an increase in lipolysis resulting in higher circulating free fatty acid levels and in ectopic fat deposition. Remission of hypercortisolism improves these metabolic changes, but very often does not result in full resolution of the abnormalities. Therefore, long-term monitoring of metabolic variables is needed even after the resolution of the excess GC levels.
Collapse
Affiliation(s)
- Rezvan Salehidoost
- Centre for Endocrinology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Márta Korbonits
- Centre for Endocrinology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| |
Collapse
|
7
|
Gong Z, Qin Y, Wang Y, Liu X, Jiang L, Cui D, Zhang M. β-cell function and insulin sensitivity contributions on incident diabetes in patients with endogenous Cushing's syndrome. Diabetes Res Clin Pract 2022; 190:109994. [PMID: 35843312 DOI: 10.1016/j.diabres.2022.109994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 07/03/2022] [Accepted: 07/11/2022] [Indexed: 11/03/2022]
Abstract
OBJECTIVE To evaluate the relative contributions of β-cell function and insulin sensitivity on the deterioration of glucose tolerance from OGTT in patients with endogenous CS. METHODS We retrospectively analyzed the data of 60 patients with CS and determined the glucose metabolism and β-cell function through OGTT. Their general characteristics were retrieved. A series of parameters for assessing insulin sensitivity and β-cell function was calculated. The logistic regression model was used to investigate insulin sensitivity and β-cell function contributions on incident diabetes. RESULTS Of the 60 patients with CS, 10 (16.7%), 21 (35%), and 29 (48.3%) were classified as CS/ normal glucose tolerance (NGT), CS/prediabetes, and CS/diabetes mellitus (DM). Compared with the HCs, the CS/NGT patients had higher HOMA-IR and lower ISI-Matsuda but with a compensatory increase in HOMA-β. Significant decreasing trends were observed in HOMA-β, AUCI/G and ΔI30/ΔG30 among CS/NGT, CS/prediabetes and CD/DM groups. The OR of incident diabetes compared with the high AUCI/G/high ISI group was significant in the low AUCI/G/high ISI group. CONCLUSION Impairment of the β-cell function had a more profound effect on incident diabetes than decreased insulin sensitivity. An approach based on an OGTT has utility for diagnosing dysglycaemia and β-cell dysfunction in patients with CS.
Collapse
Affiliation(s)
- Ziye Gong
- Department of Endocrinology, the First Affiliated Hospital with Nanjing Medical University, Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029, China
| | - Yao Qin
- Department of Endocrinology, the First Affiliated Hospital with Nanjing Medical University, Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029, China
| | - Yucheng Wang
- Department of Endocrinology, the First Affiliated Hospital with Nanjing Medical University, Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029, China
| | - Xiaoyun Liu
- Department of Endocrinology, the First Affiliated Hospital with Nanjing Medical University, Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029, China
| | - Lin Jiang
- Department of Endocrinology, the First Affiliated Hospital with Nanjing Medical University, Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029, China
| | - Dai Cui
- Department of Endocrinology, the First Affiliated Hospital with Nanjing Medical University, Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029, China
| | - Mei Zhang
- Department of Endocrinology, the First Affiliated Hospital with Nanjing Medical University, Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029, China.
| |
Collapse
|
8
|
Suksri K, Semprasert N, Limjindaporn T, Yenchitsomanus PT, Kooptiwoot S, Kooptiwut S. Cytoprotective effect of genistein against dexamethasone-induced pancreatic β-cell apoptosis. Sci Rep 2022; 12:12950. [PMID: 35902739 PMCID: PMC9334585 DOI: 10.1038/s41598-022-17372-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 07/25/2022] [Indexed: 11/10/2022] Open
Abstract
Steroid-induced diabetes is a well-known metabolic side effect of long-term use of glucocorticoid (GC). Our group recently demonstrated dexamethasone-induced pancreatic β-cell apoptosis via upregulation of TRAIL and TRAIL death receptor (DR5). Genistein protects against pancreatic β-cell apoptosis induced by toxic agents. This study aimed to investigate the cytoprotective effect of genistein against dexamethasone-induced pancreatic β-cell apoptosis in cultured rat insulinoma (INS-1) cell line and in isolated mouse islets. In the absence of genistein, dexamethasone-induced pancreatic β-cell apoptosis was associated with upregulation of TRAIL, DR5, and superoxide production, but downregulation of TRAIL decoy receptor (DcR1). Dexamethasone also activated the expression of extrinsic and intrinsic apoptotic proteins, including Bax, NF-κB, caspase-8, and caspase-3, but suppressed the expression of the anti-apoptotic Bcl-2 protein. Combination treatment with dexamethasone and genistein protected against pancreatic β-cell apoptosis, and reduced the effects of dexamethasone on the expressions of TRAIL, DR5, DcR1, superoxide production, Bax, Bcl-2, NF-κB, caspase-8, and caspase-3. Moreover, combination treatment with dexamethasone and genistein reduced the expressions of TRAIL and DR5 in isolated mouse islets. The results of this study demonstrate the cytoprotective effect of genistein against dexamethasone-induced pancreatic β-cell apoptosis in both cell line and islets via reduced TRAIL and DR5 protein expression.
Collapse
Affiliation(s)
- Kanchana Suksri
- Division of Endocrinology, Department of Physiology, Faculty of Medicine Siriraj Hospital, Mahidol University, 2 Wanglang Road, Bangkoknoi, Bangkok, 10700, Thailand
| | - Namoiy Semprasert
- Division of Endocrinology, Department of Physiology, Faculty of Medicine Siriraj Hospital, Mahidol University, 2 Wanglang Road, Bangkoknoi, Bangkok, 10700, Thailand
| | - Thawornchai Limjindaporn
- Department of Anatomy, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Pa-Thai Yenchitsomanus
- Division of Molecular Medicine, Research Department, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Sirirat Kooptiwoot
- Department of Psychiatry, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Suwattanee Kooptiwut
- Division of Endocrinology, Department of Physiology, Faculty of Medicine Siriraj Hospital, Mahidol University, 2 Wanglang Road, Bangkoknoi, Bangkok, 10700, Thailand.
| |
Collapse
|
9
|
Abstract
Generation of three-dimensional (3D)-structured functional human islets is expected to be an alternative cell source for cadaveric human islet transplantation for the treatment of insulin-dependent diabetes. Human pluripotent stem cells (hPSCs), such as human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs), offer infinite resources for newly synthesized human islets. Recent advancements in hPSCs technology have enabled direct differentiation to human islet-like clusters, which can sense glucose and secrete insulin, and those islet clusters can ameliorate diabetes when transplanted into rodents or non-human primates (NHPs). However, the generated hPSC-derived human islet-like clusters are functionally immature compared with primary human islets. There remains a challenge to establish a technology to create fully functional human islets in vitro, which are functionally and transcriptionally indistinguishable from cadaveric human islets. Understanding the complex differentiation and maturation pathway is necessary to generate fully functional human islets for a tremendous supply of high-quality human islets with less batch-to-batch difference for millions of patients. In this review, I summarized the current progress in the generation of 3D-structured human islets from pluripotent stem cells and discussed the importance of adapting physiology for in vitro functional human islet organogenesis and possible improvements with environmental cues.
Collapse
Affiliation(s)
- Eiji Yoshihara
- Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA, United States.,David Geffen School of Medicine at University of California, Los Angeles, CA, United States
| |
Collapse
|
10
|
Delangre E, Liu J, Tolu S, Maouche K, Armanet M, Cattan P, Pommier G, Bailbé D, Movassat J. Underlying mechanisms of glucocorticoid-induced β-cell death and dysfunction: a new role for glycogen synthase kinase 3. Cell Death Dis 2021; 12:1136. [PMID: 34876563 PMCID: PMC8651641 DOI: 10.1038/s41419-021-04419-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 11/10/2021] [Accepted: 11/18/2021] [Indexed: 11/08/2022]
Abstract
Glucocorticoids (GCs) are widely prescribed for their anti-inflammatory and immunosuppressive properties as a treatment for a variety of diseases. The use of GCs is associated with important side effects, including diabetogenic effects. However, the underlying mechanisms of GC-mediated diabetogenic effects in β-cells are not well understood. In this study we investigated the role of glycogen synthase kinase 3 (GSK3) in the mediation of β-cell death and dysfunction induced by GCs. Using genetic and pharmacological approaches we showed that GSK3 is involved in GC-induced β-cell death and impaired insulin secretion. Further, we unraveled the underlying mechanisms of GC-GSK3 crosstalk. We showed that GSK3 is marginally implicated in the nuclear localization of GC receptor (GR) upon ligand binding. Furthermore, we showed that GSK3 regulates the expression of GR at mRNA and protein levels. Finally, we dissected the proper contribution of each GSK3 isoform and showed that GSK3β isoform is sufficient to mediate the pro-apoptotic effects of GCs in β-cells. Collectively, in this work we identified GSK3 as a viable target to mitigate GC deleterious effects in pancreatic β-cells.
Collapse
Affiliation(s)
- Etienne Delangre
- Université de Paris, BFA, UMR 8251, CNRS, Team « Biologie et Pathologie du Pancréas Endocrine », Paris, France
| | - Junjun Liu
- Université de Paris, BFA, UMR 8251, CNRS, Team « Biologie et Pathologie du Pancréas Endocrine », Paris, France
- Shandong Institute of Endocrine & Metabolic Diseases, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China
| | - Stefania Tolu
- Université de Paris, BFA, UMR 8251, CNRS, Team « Biologie et Pathologie du Pancréas Endocrine », Paris, France
| | - Kamel Maouche
- Université de Paris, BFA, UMR 8251, CNRS, Team « Biologie et Pathologie du Pancréas Endocrine », Paris, France
| | - Mathieu Armanet
- Cell Therapy Unit, Saint-Louis hospital, AP-HP, and Université de Paris, Paris, France
| | - Pierre Cattan
- Cell Therapy Unit, Saint-Louis hospital, AP-HP, and Université de Paris, Paris, France
| | - Gaëlle Pommier
- Université de Paris, BFA, UMR 8251, CNRS, Team « Biologie et Pathologie du Pancréas Endocrine », Paris, France
| | - Danielle Bailbé
- Université de Paris, BFA, UMR 8251, CNRS, Team « Biologie et Pathologie du Pancréas Endocrine », Paris, France
| | - Jamileh Movassat
- Université de Paris, BFA, UMR 8251, CNRS, Team « Biologie et Pathologie du Pancréas Endocrine », Paris, France.
| |
Collapse
|
11
|
Lai W, Mo Y, Wang D, Zhong Y, Lu L, Wang J, Cui L, Liu Y, Yang Y. Tanshinol Alleviates Microcirculation Disturbance and Impaired Bone Formation by Attenuating TXNIP Signaling in GIO Rats. Front Pharmacol 2021; 12:722175. [PMID: 34335280 PMCID: PMC8316650 DOI: 10.3389/fphar.2021.722175] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 06/30/2021] [Indexed: 12/25/2022] Open
Abstract
Impaired bone formation is the main characteristics of glucocorticoid (GC)-induced osteoporosis (GIO), which can be ameliorated by tanshinol, an aqueous polyphenol isolated from Salvia miltiorrhiza Bunge. However, the underlying mechanism is still not entirely clear. In the present study, we determined the parameters related to microstructure and function of bone tissue, bone microcirculation, and TXNIP signaling to investigate the beneficial effects of tanshinol on skeleton and its molecular mechanism in GIO rats. Male Sprague-Dawley rats aged 4 months were administrated orally with distilled water (Con), tanshinol (Tan, 25 mg kg−1 d−1), prednisone (GC, 5 mg kg−1 d−1) and GC plus tanshinol (GC + Tan) for 14 weeks. The results demonstrated that tanshinol played a significant preventive role in bone loss, impaired microstructure, dysfunction of bone metabolism and poor bone quality, based on analysis of correlative parameters acquired from the measurement by using Micro-CT, histomorphometry, ELISA and biomechanical assay. Tanshinol also showed a significant protective effect in bone microcirculation according to the evidence of microvascular perfusion imaging of cancellous bone in GIO rats, as well as the migration ability of human endothelial cells (EA.hy926, EA cells). Moreover, tanshinol also attenuated GC-elicited the activation of TXNIP signaling pathway, and simultaneously reversed the down-regulation of Wnt and VEGF pathway as manifested by using Western-blot method in GIO rats, EA cells, and human osteoblast-like MG63 cells (MG cells). Collectively, our data highlighted that tanshinol ameliorated poor bone health mediated by activation of TXNIP signaling via inhibiting microcirculation disturbance and the following impaired bone formation in GIO rats.
Collapse
Affiliation(s)
- Wenxiu Lai
- Department of Pharmacology, Guangdong Key Laboratory for Research and Development of Natural Drugs, Guangdong Medical University, Zhanjiang, China.,Department of Phamacy, Yuebei People's Hospital, Shaoguan, China
| | - Yulin Mo
- Department of Pharmacology, Guangdong Key Laboratory for Research and Development of Natural Drugs, Guangdong Medical University, Zhanjiang, China.,Department of Orthopedics and Traumatology, Nanning Hospital of Traditional Chinese Medicine, Guangxi University of Chinese Medicine, Nanning, China
| | - Dongtao Wang
- Department of Traditional Chinese Medicine, Shenzhen Hospital, Southern Medical University, Shenzhen, China.,Department of the Ministry of Science and Technology, Guangxi International Zhuang Medicine Hospital, Nanning, China
| | - Ying Zhong
- Department of Pharmacology, Guangdong Key Laboratory for Research and Development of Natural Drugs, Guangdong Medical University, Zhanjiang, China
| | - Lujiao Lu
- Department of Pharmacology, Guangdong Key Laboratory for Research and Development of Natural Drugs, Guangdong Medical University, Zhanjiang, China
| | - Jiajia Wang
- Department of Pharmacology, Guangdong Key Laboratory for Research and Development of Natural Drugs, Guangdong Medical University, Zhanjiang, China
| | - Liao Cui
- Department of Pharmacology, Guangdong Key Laboratory for Research and Development of Natural Drugs, Guangdong Medical University, Zhanjiang, China.,Marine Medical Research Institute, Guangdong Medical University, Zhanjiang, China
| | - Yanzhi Liu
- Department of Pharmacology, Guangdong Key Laboratory for Research and Development of Natural Drugs, Guangdong Medical University, Zhanjiang, China.,Marine Medical Research Institute, Guangdong Medical University, Zhanjiang, China
| | - Yajun Yang
- Department of Pharmacology, Guangdong Key Laboratory for Research and Development of Natural Drugs, Guangdong Medical University, Zhanjiang, China.,Marine Medical Research Institute, Guangdong Medical University, Zhanjiang, China
| |
Collapse
|
12
|
Noblet B, Benhamed F, O-Sullivan I, Zhang W, Filhoulaud G, Montagner A, Polizzi A, Marmier S, Burnol AF, Guilmeau S, Issad T, Guillou H, Bernard C, Unterman T, Postic C. Dual regulation of TxNIP by ChREBP and FoxO1 in liver. iScience 2021; 24:102218. [PMID: 33748706 PMCID: PMC7966993 DOI: 10.1016/j.isci.2021.102218] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 11/17/2020] [Accepted: 02/18/2021] [Indexed: 12/12/2022] Open
Abstract
TxNIP (Thioredoxin-interacting protein) is considered as a potential drug target for type 2 diabetes. Although TxNIP expression is correlated with hyperglycemia and glucotoxicity in pancreatic β cells, its regulation in liver cells has been less investigated. In the current study, we aim at providing a better understanding of Txnip regulation in hepatocytes in response to physiological stimuli and in the context of hyperglycemia in db/db mice. We focused on regulatory pathways governed by ChREBP (Carbohydrate Responsive Element Binding Protein) and FoxO1 (Forkhead box protein O1), transcription factors that play central roles in mediating the effects of glucose and fasting on gene expression, respectively. Studies using genetically modified mice reveal that hepatic TxNIP is up-regulated by both ChREBP and FoxO1 in liver cells and that its expression strongly correlates with fasting, suggesting a major role for this protein in the physiological adaptation to nutrient restriction. TxNIP is considered as a potential candidate drug target for type 2 diabetes We provide better understanding of Txnip regulation and function in liver Hepatic Txnip is up-regulated by both ChREBP and FoxO1 transcription factors We suggest a role for TxNIP in the physiological adaptation to nutrient restriction
Collapse
Affiliation(s)
- Benedicte Noblet
- Université de Paris, Institut Cochin, CNRS, INSERM, 75014 Paris, France
| | - Fadila Benhamed
- Université de Paris, Institut Cochin, CNRS, INSERM, 75014 Paris, France
| | - InSug O-Sullivan
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612.,Medical Research Service, Jesse Brown VA Medical Center, Chicago, IL 60612, USA
| | - Wenwei Zhang
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612.,Medical Research Service, Jesse Brown VA Medical Center, Chicago, IL 60612, USA
| | - Gaëlle Filhoulaud
- Université de Paris, Institut Cochin, CNRS, INSERM, 75014 Paris, France
| | - Alexandra Montagner
- Toxalim, Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, Toulouse 31027, France
| | - Arnaud Polizzi
- Toxalim, Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, Toulouse 31027, France
| | - Solenne Marmier
- Université de Paris, Institut Cochin, CNRS, INSERM, 75014 Paris, France
| | | | - Sandra Guilmeau
- Université de Paris, Institut Cochin, CNRS, INSERM, 75014 Paris, France
| | - Tarik Issad
- Université de Paris, Institut Cochin, CNRS, INSERM, 75014 Paris, France
| | - Hervé Guillou
- Toxalim, Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, Toulouse 31027, France
| | | | - Terry Unterman
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612.,Medical Research Service, Jesse Brown VA Medical Center, Chicago, IL 60612, USA
| | - Catherine Postic
- Université de Paris, Institut Cochin, CNRS, INSERM, 75014 Paris, France
| |
Collapse
|
13
|
Beaupere C, Liboz A, Fève B, Blondeau B, Guillemain G. Molecular Mechanisms of Glucocorticoid-Induced Insulin Resistance. Int J Mol Sci 2021; 22:E623. [PMID: 33435513 DOI: 10.3390/ijms22020623] [Citation(s) in RCA: 72] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/29/2020] [Accepted: 01/02/2021] [Indexed: 12/12/2022] Open
Abstract
Glucocorticoids (GCs) are steroids secreted by the adrenal cortex under the hypothalamic-pituitary-adrenal axis control, one of the major neuro-endocrine systems of the organism. These hormones are involved in tissue repair, immune stability, and metabolic processes, such as the regulation of carbohydrate, lipid, and protein metabolism. Globally, GCs are presented as ‘flight and fight’ hormones and, in that purpose, they are catabolic hormones required to mobilize storage to provide energy for the organism. If acute GC secretion allows fast metabolic adaptations to respond to danger, stress, or metabolic imbalance, long-term GC exposure arising from treatment or Cushing’s syndrome, progressively leads to insulin resistance and, in fine, cardiometabolic disorders. In this review, we briefly summarize the pharmacological actions of GC and metabolic dysregulations observed in patients exposed to an excess of GCs. Next, we describe in detail the molecular mechanisms underlying GC-induced insulin resistance in adipose tissue, liver, muscle, and to a lesser extent in gut, bone, and brain, mainly identified by numerous studies performed in animal models. Finally, we present the paradoxical effects of GCs on beta cell mass and insulin secretion by the pancreas with a specific focus on the direct and indirect (through insulin-sensitive organs) effects of GCs. Overall, a better knowledge of the specific action of GCs on several organs and their molecular targets may help foster the understanding of GCs’ side effects and design new drugs that possess therapeutic benefits without metabolic adverse effects.
Collapse
|
14
|
Zhou W, Shao W, Zhang Y, Liu D, Liu M, Jin T. Glucagon-like peptide-1 receptor mediates the beneficial effect of liraglutide in an acute lung injury mouse model involving the thioredoxin-interacting protein. Am J Physiol Endocrinol Metab 2020; 319:E568-E578. [PMID: 32723174 PMCID: PMC7839242 DOI: 10.1152/ajpendo.00292.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Repurposing clinically used drugs is among the important strategies in drug discovery. Glucagon-like peptide-1 (GLP-1) and its diabetes-based drugs, such as liraglutide, possess a spectrum of extra-pancreatic functions, while GLP-1 receptor (GLP-1R) is most abundantly expressed in the lung. Recent studies have suggested that GLP-1-based drugs exert beneficial effects in chronic, as well as acute, lung injury rodent models. Here, we show that liraglutide pretreatment reduced LPS induced acute lung injury in mice. It significantly reduced lung injury score, wet/dry lung weight ratio, bronchoalveolar lavage fluid immune cell count and protein concentration, and cell apoptosis in the lung, and it was associated with reduced lung inflammatory cytokine and chemokine gene expression. Importantly, these effects were virtually absent in GLP-1R-/- mice. A well-known function of GLP-1 and GLP-based drugs in pancreatic β-cells is the attenuation of high-glucose stimulated expression of thioredoxin-interacting protein (TxNIP), a key component of inflammasome. LPS-challenged lungs showed elevated TxNIP mRNA and protein expression, which was attenuated by liraglutide treatment in a GLP-1R-dependent manner. Hence, our observations suggest that GLP-1R is essential in mediating beneficial effects of liraglutide in acute lung injury, with the inflammasome component TxNIP as a potential target.
Collapse
Affiliation(s)
- Wenyong Zhou
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Thoracic Surgery, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Weijuan Shao
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Yu Zhang
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Dinghui Liu
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Cardiology, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Mingyao Liu
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Department of Surgery, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Tianru Jin
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Banting and Best Diabetes Centre, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| |
Collapse
|
15
|
Yoshihara E. TXNIP/TBP-2: A Master Regulator for Glucose Homeostasis. Antioxidants (Basel) 2020; 9:E765. [PMID: 32824669 DOI: 10.3390/antiox9080765] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/09/2020] [Accepted: 08/10/2020] [Indexed: 02/07/2023] Open
Abstract
Identification of thioredoxin binding protein-2 (TBP-2), which is currently known as thioredoxin interacting protein (TXNIP), as an important binding partner for thioredoxin (TRX) revealed that an evolutionarily conserved reduction-oxidation (redox) signal complex plays an important role for pathophysiology. Due to the reducing activity of TRX, the TRX/TXNIP signal complex has been shown to be an important regulator for redox-related signal transduction in many types of cells in various species. In addition to its role in redox-dependent regulation, TXNIP has cellular functions that are performed in a redox-independent manner, which largely rely on their scaffolding function as an ancestral α-Arrestin family. Both the redox-dependent and -independent TXNIP functions serve as regulatory pathways in glucose metabolism. This review highlights the key advances in understanding TXNIP function as a master regulator for whole-body glucose homeostasis. The potential for therapeutic advantages of targeting TXNIP in diabetes and the future direction of the study are also discussed.
Collapse
|
16
|
Song S, Qiu D, Wang Y, Wei J, Wu H, Wu M, Wang S, Zhou X, Shi Y, Duan H. TXNIP deficiency mitigates podocyte apoptosis via restraining the activation of mTOR or p38 MAPK signaling in diabetic nephropathy. Exp Cell Res 2020; 388:111862. [PMID: 31982382 DOI: 10.1016/j.yexcr.2020.111862] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 01/19/2020] [Accepted: 01/22/2020] [Indexed: 12/22/2022]
Abstract
Thioredoxin-interacting protein (TXNIP), is identified as an inhibitor of the thiol oxidoreductase thioredoxin that acts endogenously, and is increased by high glucose (HG). In this study, we investigated the potential function of TXNIP on apoptosis of podocytes and its potential mechanism in vivo and in vitro in diabetic nephropathy (DN). TXNIP silencing attenuated HG-induced apoptosis and obliterated the activation of signaling pathways of mammalian target of rapamycin (mTOR) and p38 mitogen-activated protein kinase (MAPK) in conditionally immortalized mouse podocytes. Furthermore, the Raptor and Rictor shRNAs, mTOR specific inhibitor KU-0063794 and p38 MAPK inhibitor SB203580 were used to assess the role of mTOR or p38 MAPK pathway on podocyte apoptosis induced by HG. The Rictor and Raptor shRNAs and KU-0063794 appeared to reduce HG-induced apoptosis in podocytes. Simultaneously, SB203580 could also restrain HG-induced apoptosis in podocytes. Streptozotocin rendered equivalent diabetes in TXNIP-/- (TKO) and wild-type (WT) control mice. TXNIP deficiency mitigated renal injury in diabetic mice. Additionally, TXNIP deficiency also descended the apoptosis-related protein and Nox4 levels, the mTOR signaling activation and the p38 MAPK phosphorylation in podocytes of diabetic mice. All these data indicate that TXNIP deficiency may mitigate apoptosis of podocytes by inhibiting p38 MAPK or mTOR signaling pathway in DN, underlining TXNIP as a putative target for therapy.
Collapse
|
17
|
He S, Wu W, Wan Y, Nandakumar KS, Cai X, Tang X, Liu S, Yao X. GLP-1 Receptor Activation Abrogates β-Cell Dysfunction by PKA Cα-Mediated Degradation of Thioredoxin Interacting Protein. Front Pharmacol 2019; 10:1230. [PMID: 31708773 PMCID: PMC6824261 DOI: 10.3389/fphar.2019.01230] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 09/27/2019] [Indexed: 11/29/2022] Open
Abstract
Glucagon-like peptide 1 receptor (GLP-1R) agonist (Exendin-4) is a well-known agent used to improve β-cell dysfunctions via protein kinase A (PKA), but the detailed downstream molecular mechanisms are still elusive. We have now found that PKA Cα mediated- TXNIP phosphorylation and degradation played a vital role in the β-cell protective role of exendin-4. After PKA activator (Exendin-4 or FSK) treatment, PKA Cα could directly interact with TXNIP by bimolecular fluorescence complementation and Co-IP assays in INS-1 cells. And PKA Cα overexpression decreased TXNIP level, whereas TXNIP level was largely increased in PKA Cα-KO β-cells by CRISPR-Cas9. Interestingly, TXNIP overexpression or PKA Cα-KO has impaired β-cell functions, including loss of insulin secretion and activation of inflammation. PKA Cα directly phosphorylated TXNIP at Ser307 and Ser308 positions, leading to its degradation via activation of cellular proteasome pathway. Consistent with this observation, TXNIP (S307/308A) mutant resisted the degradation effects of PKA Cα. However, exendin-4 neither affected TXNIP level in TXNIP (S307/308A) mutant overexpressed β-cells nor in PKA Cα-KO β-cells. Moreover, exendin-4 treatment reduced the inflammation gene expression in TXNIP overexpressed β-cells, but exendin-4 treatment has no effect on the inflammation gene expression in TXNIP (S307/308A) overexpressed β-cells. In conclusion, our study reveals the integral role of PKA Cα/TXNIP signaling in pancreatic β-cells and suggests that PKA Cα-mediated TXNIP degradation is vital in β-cell protective effects of exendin-4.
Collapse
Affiliation(s)
- Shijun He
- State Key Laboratory of Organ Failure Research, Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
| | - Wenyu Wu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Yihong Wan
- State Key Laboratory of Organ Failure Research, Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
| | - Kutty Selva Nandakumar
- State Key Laboratory of Organ Failure Research, Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
| | - Xiuchao Cai
- State Key Laboratory of Organ Failure Research, Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
| | - Xiaodong Tang
- State Key Laboratory of Organ Failure Research, Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
| | - Shuwen Liu
- State Key Laboratory of Organ Failure Research, Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China.,Center of Pharmacy, Nanhai Hospital, Southern Medical University, Foshan, China
| | - Xingang Yao
- State Key Laboratory of Organ Failure Research, Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China.,Center of Clinical Pharmacy, Nanfang Hospital, Southern Medical University, Guangzhou, China
| |
Collapse
|
18
|
Nasoohi S, Ismael S, Ishrat T. Thioredoxin-Interacting Protein (TXNIP) in Cerebrovascular and Neurodegenerative Diseases: Regulation and Implication. Mol Neurobiol 2018; 55:7900-20. [PMID: 29488135 DOI: 10.1007/s12035-018-0917-z] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Accepted: 01/21/2018] [Indexed: 02/07/2023]
Abstract
Neurological diseases, including acute attacks (e.g., ischemic stroke) and chronic neurodegenerative diseases (e.g., Alzheimer's disease), have always been one of the leading cause of morbidity and mortality worldwide. These debilitating diseases represent an enormous disease burden, not only in terms of health suffering but also in economic costs. Although the clinical presentations differ for these diseases, a growing body of evidence suggests that oxidative stress and inflammatory responses in brain tissue significantly contribute to their pathology. However, therapies attempting to prevent oxidative damage or inhibiting inflammation have shown little success. Identification and targeting endogenous "upstream" mediators that normalize such processes will lead to improve therapeutic strategy of these diseases. Thioredoxin-interacting protein (TXNIP) is an endogenous inhibitor of the thioredoxin (TRX) system, a major cellular thiol-reducing and antioxidant system. TXNIP regulating redox/glucose-induced stress and inflammation, now is known to get upregulated in stroke and other brain diseases, and represents a promising therapeutic target. In particular, there is growing evidence that glucose strongly induces TXNIP in multiple cell types, suggesting possible physiological roles of TXNIP in glucose metabolism. Recently, a significant body of literature has supported an essential role of TXNIP in the activation of the NOD-like receptor protein (NLRP3)-inflammasome, a well-established multi-molecular protein complex and a pivotal mediator of sterile inflammation. Accordingly, TXNIP has been postulated to reside centrally in detecting cellular damage and mediating inflammatory responses to tissue injury. The majority of recent studies have shown that pharmacological inhibition or genetic deletion of TXNIP is neuroprotective and able to reduce detrimental aspects of pathology following cerebrovascular and neurodegenerative diseases. Conspicuously, the mainstream of the emerging evidences is highlighting TXNIP link to damaging signals in endothelial cells. Thereby, here, we keep the trend to present the accumulative data on CNS diseases dealing with vascular integrity. This review aims to summarize evidence supporting the significant contribution of regulatory mechanisms of TXNIP with the development of brain diseases, explore pharmacological strategies of targeting TXNIP, and outline obstacles to be considered for efficient clinical translation.
Collapse
|
19
|
Su WJ, Peng W, Gong H, Liu YZ, Zhang Y, Lian YJ, Cao ZY, Wu R, Liu LL, Wang B, Wang YX, Jiang CL. Antidiabetic drug glyburide modulates depressive-like behavior comorbid with insulin resistance. J Neuroinflammation 2017; 14:210. [PMID: 29084550 PMCID: PMC5663104 DOI: 10.1186/s12974-017-0985-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 10/23/2017] [Indexed: 12/12/2022] Open
Abstract
Background Abundant reports indicated that depression was often comorbid with type 2 diabetes and even metabolic syndrome. Considering they might share common biological origins, it was tentatively attributed to the chronic cytokine-mediated inflammatory response which was induced by dysregulation of HPA axis and overactivation of innate immunity. However, the exact mechanisms remain obscure. Herein, we mainly focused on the function of the NLRP3 inflammasome to investigate this issue. Methods Male C57BL/6 mice were subjected to 12 weeks of chronic unpredictable mild stress (CUMS), some of which were injected with glyburide or fluoxetine. After CUMS procedure, behavioral and metabolic tests were carried out. In order to evaluate the systemic inflammation associated with inflammasome activation, IL-1β and inflammasome components in hippocampi and pancreases, as well as corticosterone and IL-1β in serum were detected separately. Moreover, immunostaining was performed to assess morphologic characteristics of pancreases. Results In the present study, we found that 12 weeks’ chronic stress resulted in depressive-like behavior comorbid with insulin resistance. Furthermore, antidiabetic drug glyburide, an inhibitor of the NLRP3 inflammasome, was discovered to be effective in preventing the experimental comorbidity. In brief, it improved behavioral performance, ameliorated insulin intolerance as well as insulin signaling in the hippocampus possibly through inhibiting NLRP3 inflammasome activation by suppressing the expression of TXNIP. Conclusions All these evidence supported our hypothesis that chronic stress led to comorbidity of depressive-like behavior and insulin resistance via long-term mild inflammation. More importantly, based on the beneficial effects of blocking the activation of the NLRP3 inflammasome, we provided a potential therapeutic target for clinical comorbidity and a new strategy for management of both diabetes and depression.
Collapse
Affiliation(s)
- Wen-Jun Su
- Laboratory of Stress Medicine, Faculty of Psychology and Mental Health, Second Military Medical University, 800 Xiangyin Road, Shanghai, China
| | - Wei Peng
- Laboratory of Stress Medicine, Faculty of Psychology and Mental Health, Second Military Medical University, 800 Xiangyin Road, Shanghai, China
| | - Hong Gong
- Laboratory of Stress Medicine, Faculty of Psychology and Mental Health, Second Military Medical University, 800 Xiangyin Road, Shanghai, China
| | - Yun-Zi Liu
- Laboratory of Stress Medicine, Faculty of Psychology and Mental Health, Second Military Medical University, 800 Xiangyin Road, Shanghai, China
| | - Yi Zhang
- Department of Psychiatry, Faculty of Psychology and Mental Health, Second Military Medical University, 800 Xiangyin Road, Shanghai, China
| | - Yong-Jie Lian
- Laboratory of Stress Medicine, Faculty of Psychology and Mental Health, Second Military Medical University, 800 Xiangyin Road, Shanghai, China
| | - Zhi-Yong Cao
- Laboratory of Stress Medicine, Faculty of Psychology and Mental Health, Second Military Medical University, 800 Xiangyin Road, Shanghai, China.,Department of Psychiatry, The 102nd Hospital of PLA, 55 North Heping Road, Changzhou, China
| | - Ran Wu
- Laboratory of Stress Medicine, Faculty of Psychology and Mental Health, Second Military Medical University, 800 Xiangyin Road, Shanghai, China
| | - Lin-Lin Liu
- Laboratory of Stress Medicine, Faculty of Psychology and Mental Health, Second Military Medical University, 800 Xiangyin Road, Shanghai, China
| | - Bo Wang
- Laboratory of Stress Medicine, Faculty of Psychology and Mental Health, Second Military Medical University, 800 Xiangyin Road, Shanghai, China
| | - Yun-Xia Wang
- Laboratory of Stress Medicine, Faculty of Psychology and Mental Health, Second Military Medical University, 800 Xiangyin Road, Shanghai, China
| | - Chun-Lei Jiang
- Laboratory of Stress Medicine, Faculty of Psychology and Mental Health, Second Military Medical University, 800 Xiangyin Road, Shanghai, China.
| |
Collapse
|
20
|
Scaroni C, Zilio M, Foti M, Boscaro M. Glucose Metabolism Abnormalities in Cushing Syndrome: From Molecular Basis to Clinical Management. Endocr Rev 2017; 38:189-219. [PMID: 28368467 DOI: 10.1210/er.2016-1105] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 03/15/2017] [Indexed: 12/13/2022]
Abstract
An impaired glucose metabolism, which often leads to the onset of diabetes mellitus (DM), is a common complication of chronic exposure to exogenous and endogenous glucocorticoid (GC) excess and plays an important part in contributing to morbidity and mortality in patients with Cushing syndrome (CS). This article reviews the pathogenesis, epidemiology, diagnosis, and management of changes in glucose metabolism associated with hypercortisolism, addressing both the pathophysiological aspects and the clinical and therapeutic implications. Chronic hypercortisolism may have pleiotropic effects on all major peripheral tissues governing glucose homeostasis. Adding further complexity, both genomic and nongenomic mechanisms are directly induced by GCs in a context-specific and cell-/organ-dependent manner. In this paper, the discussion focuses on established and potential pathologic molecular mechanisms that are induced by chronically excessive circulating levels of GCs and affect glucose homeostasis in various tissues. The management of patients with CS and DM includes treating their hyperglycemia and correcting their GC excess. The effects on glycemic control of various medical therapies for CS are reviewed in this paper. The association between DM and subclinical CS and the role of screening for CS in diabetic patients are also discussed.
Collapse
Affiliation(s)
- Carla Scaroni
- Endocrinology Unit, Department of Medicine, DIMED, University of Padova, Via Ospedale 105, 35128 Padua, Italy
| | - Marialuisa Zilio
- Endocrinology Unit, Department of Medicine, DIMED, University of Padova, Via Ospedale 105, 35128 Padua, Italy
| | - Michelangelo Foti
- Department of Cell Physiology & Metabolism, Centre Médical Universitaire, 1 Rue Michel Servet, 1211 Genèva, Switzerland
| | - Marco Boscaro
- Endocrinology Unit, Department of Medicine, DIMED, University of Padova, Via Ospedale 105, 35128 Padua, Italy
| |
Collapse
|
21
|
Abstract
The BH3-only Bim protein is a major determinant for initiating the intrinsic apoptotic pathway under both physiological and pathophysiological conditions. Tight regulation of its expression and activity at the transcriptional, translational and post-translational levels together with the induction of alternatively spliced isoforms with different pro-apoptotic potential, ensure timely activation of Bim. Under physiological conditions, Bim is essential for shaping immune responses where its absence promotes autoimmunity, while too early Bim induction eliminates cytotoxic T cells prematurely, resulting in chronic inflammation and tumor progression. Enhanced Bim induction in neurons causes neurodegenerative disorders including Alzheimer's, Parkinson's and Huntington's diseases. Moreover, type I diabetes is promoted by genetically predisposed elevation of Bim in β-cells. On the contrary, cancer cells have developed mechanisms that suppress Bim expression necessary for tumor progression and metastasis. This review focuses on the intricate network regulating Bim activity and its involvement in physiological and pathophysiological processes.
Collapse
Affiliation(s)
- Ronit Vogt Sionov
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel Canada, Hebrew University, Hadassah Medical School, Jerusalem, Israel
| | - Spiros A Vlahopoulos
- First Department of Pediatrics, University of Athens, Horemeio Research Laboratory, Thivon and Levadias, Goudi, Athens, Greece
| | - Zvi Granot
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel Canada, Hebrew University, Hadassah Medical School, Jerusalem, Israel
| |
Collapse
|
22
|
Harada N, Katsuki T, Takahashi Y, Masuda T, Yoshinaga M, Adachi T, Izawa T, Kuwamura M, Nakano Y, Yamaji R, Inui H. Androgen receptor silences thioredoxin-interacting protein and competitively inhibits glucocorticoid receptor-mediated apoptosis in pancreatic β-Cells. J Cell Biochem 2016; 116:998-1006. [PMID: 25639671 DOI: 10.1002/jcb.25054] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 12/18/2014] [Indexed: 01/09/2023]
Abstract
Androgen receptor (AR) is known to bind to the same cis-element that glucocorticoid receptor (GR) binds to. However, the effects of androgen signaling on glucocorticoid signaling have not yet been elucidated. Here, we investigated the effects of testosterone on dexamethasone (DEX, a synthetic glucocorticoid)-induced apoptosis of pancreatic β-cells, which might be involved in the pathogenesis of type 2 diabetes mellitus in males. We used INS-1 #6 cells, which were isolated from the INS-1 pancreatic β-cell line and which express high levels of AR. Testosterone and dihydrotestosterone inhibited apoptosis induced by DEX in INS-1 #6 cells. AR knockdown and the AR antagonist hydroxyflutamide each diminished the anti-apoptotic effects of testosterone. AR was localized in the nucleus of both INS-1 #6 cells and pancreatic β-cells of male rats. Induction of thioredoxin-interacting protein (TXNIP) is known to cause pro-apoptotic effects in β-cells. Testosterone suppressed the DEX-induced increase of TXNIP at the transcriptional level. A Chromatin immunoprecipitation assays showed that both AR and GR competitively bound to the TXNIP promoter in ligand-dependent manners. Recombinant DNA-binding domain of AR bound to the same cis-element of the TXNIP promoter that GR binds to. Our results show that AR and GR competitively bind to the same cis-element of TXNIP promoter as a silencer and enhancer, respectively. These results indicate that androgen signaling functionally competes with glucocorticoid signaling in pancreatic β-cell apoptosis.
Collapse
Affiliation(s)
- Naoki Harada
- Division of Applied Life Sciences, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka, 5998531, Japan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Abstract
In response to stress, the central nervous system initiates a signaling cascade, which leads to the production of glucocorticoids (GCs). GCs act through the glucocorticoid receptor (GR) to coordinate the appropriate cellular response with the primary goal of mobilizing the storage forms of carbon precursors to generate a continuous glucose supply for the brain. Although GCs are critical for maintaining energy homeostasis, excessive GC stimulation leads to a number of undesirable side effects, including hyperglycemia, insulin resistance, fatty liver, obesity, and muscle wasting leading to severe metabolic dysfunction. Summarized below are the diverse metabolic roles of glucocorticoids in energy homeostasis and dysregulation, focusing specifically on glucose, lipid, and protein metabolism.
Collapse
Affiliation(s)
- Lilia Magomedova
- Department of Pharmaceutical Sciences, University of Toronto, Toronto, ON, M5S 3M2, Canada
| | - Carolyn L Cummins
- Department of Pharmaceutical Sciences, University of Toronto, Toronto, ON, M5S 3M2, Canada.
| |
Collapse
|
24
|
Abstract
Glucocorticoids are steroid hormones that regulate multiple aspects of glucose homeostasis. Glucocorticoids promote gluconeogenesis in liver, whereas in skeletal muscle and white adipose tissue they decrease glucose uptake and utilization by antagonizing insulin response. Therefore, excess glucocorticoid exposure causes hyperglycemia and insulin resistance. Glucocorticoids also regulate glycogen metabolism. In liver, glucocorticoids increase glycogen storage, whereas in skeletal muscle they play a permissive role for catecholamine-induced glycogenolysis and/or inhibit insulin-stimulated glycogen synthesis. Moreover, glucocorticoids modulate the function of pancreatic α and β cells to regulate the secretion of glucagon and insulin, two hormones that play a pivotal role in the regulation of blood glucose levels. Overall, the major glucocorticoid effect on glucose homeostasis is to preserve plasma glucose for brain during stress, as transiently raising blood glucose is important to promote maximal brain function. In this chapter we will discuss the current understanding of the mechanisms underlying different aspects of glucocorticoid-regulated mammalian glucose homeostasis.
Collapse
|
25
|
Karunakaran U, Moon JS, Lee HW, Won KC. CD36 initiated signaling mediates ceramide-induced TXNIP expression in pancreatic beta-cells. Biochim Biophys Acta Mol Basis Dis 2015; 1852:2414-22. [PMID: 26297980 DOI: 10.1016/j.bbadis.2015.08.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 08/13/2015] [Accepted: 08/17/2015] [Indexed: 01/25/2023]
Abstract
Diverse mechanisms are involved in the pathogenesis of β-cell failure in type 2 diabetes. Of them, the accumulation of ceramide, a bioactive lipid metabolite, is suggested to play a major role in inflammatory and stress responses that induce diabetes. However, the downstream inflammatory target of ceramide has not been defined. Using rat islets and the INS-1 β-cell line, we hypothesized that activation of the redox sensitive protein TXNIP is involved in ceramide-induced β-cell dysfunction. Incubation of INS-1 cells and primary islets with C2-ceramide (N-acetyl-sphingosine) downregulated insulin and PDX-1 expression and increased β-cell apoptosis. Ceramide treatment induced a time dependent increase in TXNIP gene expression accompanied by activation of nuclear factor (NF)-κB and reduced mitochondrial thioredoxin (TRX) activity. Pretreatment with sulfo-N-succinimidyl oleate (SSO), an irreversible inhibitor of the scavenger receptor CD36, blocked ceramide-induced up-regulation of TXNIP expression and activity of NF-κB. Blockade of NF-κB nuclear translocation by the peptide SN50 prevented ceramide-mediated TXNIP induction. Furthermore, SSO also attenuated ceramide-induced early loss of insulin signaling and apoptosis. Collectively, our results unveil a novel role of CD36 in early molecular events leading to NF-κB activation and TXNIP expression. These data suggest that CD36 dependent NF-κB-TXNIP signaling contributes to the ceramide-induced pathogenesis of pancreatic β-cell dysfunction and failure.
Collapse
Affiliation(s)
- Udayakumar Karunakaran
- Institute of Medical Science, Yeungnam University College of Medicine, Daegu, South Korea
| | - Jun Sung Moon
- Department of Internal Medicine, Yeungnam University College of Medicine, Daegu, South Korea
| | - Hyoung Woo Lee
- Department of Internal Medicine, Yeungnam University College of Medicine, Daegu, South Korea
| | - Kyu Chang Won
- Institute of Medical Science, Yeungnam University College of Medicine, Daegu, South Korea; Department of Internal Medicine, Yeungnam University College of Medicine, Daegu, South Korea.
| |
Collapse
|
26
|
Abstract
Pancreatic β-cells are responsible for insulin production, and loss of functional β-cell mass is now recognized as a critical step in the pathogenesis of both type 1 and type 2 diabetes. However, the factors controlling the life and death of the pancreatic β-cell have only started to be elucidated. Discovered as the top glucose-induced gene in a human islet microarray study 12 years ago, thioredoxin-interacting protein (TXNIP) has now emerged as such a key player in pancreatic β-cell biology. Since then, β-cell expression of TXNIP has been found to be tightly regulated by multiple factors and to be dramatically increased in diabetic islets. Elevated TXNIP levels induce β-cell apoptosis, whereas TXNIP deficiency protects against type 1 and type 2 diabetes by promoting β-cell survival. TXNIP interacts with and inhibits thioredoxin and thereby controls the cellular redox state, but it also belongs to the α-arrestin family of proteins and regulates a variety of metabolic processes. Most recently, TXNIP has been discovered to control β-cell microRNA expression, β-cell function, and insulin production. In this review, the current state of knowledge regarding regulation and function of TXNIP in the pancreatic β-cell and the implications for drug development are discussed.
Collapse
Affiliation(s)
- Anath Shalev
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Alabama at Birmingham, Birmingham, Alabama 35294
| |
Collapse
|
27
|
Abstract
The prevalence of diabetes is increasing rapidly worldwide. A cardinal feature of most forms of diabetes is the lack of insulin-producing capability, due to the loss of insulin-producing β-cells, impaired glucose-sensitive insulin secretion from the β-cell, or a combination thereof, the reasons for which largely remain elusive. Reversible phosphorylation is an important and versatile mechanism for regulating the biological activity of many intracellular proteins, which, in turn, controls a variety of cellular functions. For instance, significant changes in protein kinase activities and in protein phosphorylation patterns occur subsequent to the stimulation of insulin release by glucose. Therefore, the molecular mechanisms regulating the phosphorylation of proteins involved in the insulin secretory process by the β-cell have been extensively investigated. However, far less is known about the role and regulation of protein dephosphorylation by various protein phosphatases. Herein, we review extant data implicating serine/threonine and tyrosine phosphatases in various aspects of healthy and diabetic islet biology, ranging from control of hormonal stimulus-secretion coupling to mitogenesis and apoptosis.
Collapse
Affiliation(s)
- Henrik Ortsäter
- Biovation Park TelgeSödertälje, SwedenResearch UnitSödertälje Hospital, SE-152 86 Södertälje, SwedenDegenerative Disease ProgramSanford-Burnham Medical Research Institute, Del E. Webb Neuroscience, Aging and Stem Cell Research Center, 10901 North Torrey Pines Road, La Jolla, California 92037, USADepartment of Biochemistry and Molecular BiologyCollege of Medicine, University of South Alabama, Mobile, Alabama 36688, USADepartment of Internal MedicineSödertälje Hospital, Södertälje, SwedenBiovation Park TelgeSödertälje, SwedenResearch UnitSödertälje Hospital, SE-152 86 Södertälje, SwedenDegenerative Disease ProgramSanford-Burnham Medical Research Institute, Del E. Webb Neuroscience, Aging and Stem Cell Research Center, 10901 North Torrey Pines Road, La Jolla, California 92037, USADepartment of Biochemistry and Molecular BiologyCollege of Medicine, University of South Alabama, Mobile, Alabama 36688, USADepartment of Internal MedicineSödertälje Hospital, Södertälje, Sweden
| | - Nina Grankvist
- Biovation Park TelgeSödertälje, SwedenResearch UnitSödertälje Hospital, SE-152 86 Södertälje, SwedenDegenerative Disease ProgramSanford-Burnham Medical Research Institute, Del E. Webb Neuroscience, Aging and Stem Cell Research Center, 10901 North Torrey Pines Road, La Jolla, California 92037, USADepartment of Biochemistry and Molecular BiologyCollege of Medicine, University of South Alabama, Mobile, Alabama 36688, USADepartment of Internal MedicineSödertälje Hospital, Södertälje, Sweden
| | - Richard E Honkanen
- Biovation Park TelgeSödertälje, SwedenResearch UnitSödertälje Hospital, SE-152 86 Södertälje, SwedenDegenerative Disease ProgramSanford-Burnham Medical Research Institute, Del E. Webb Neuroscience, Aging and Stem Cell Research Center, 10901 North Torrey Pines Road, La Jolla, California 92037, USADepartment of Biochemistry and Molecular BiologyCollege of Medicine, University of South Alabama, Mobile, Alabama 36688, USADepartment of Internal MedicineSödertälje Hospital, Södertälje, Sweden
| | - Åke Sjöholm
- Biovation Park TelgeSödertälje, SwedenResearch UnitSödertälje Hospital, SE-152 86 Södertälje, SwedenDegenerative Disease ProgramSanford-Burnham Medical Research Institute, Del E. Webb Neuroscience, Aging and Stem Cell Research Center, 10901 North Torrey Pines Road, La Jolla, California 92037, USADepartment of Biochemistry and Molecular BiologyCollege of Medicine, University of South Alabama, Mobile, Alabama 36688, USADepartment of Internal MedicineSödertälje Hospital, Södertälje, SwedenBiovation Park TelgeSödertälje, SwedenResearch UnitSödertälje Hospital, SE-152 86 Södertälje, SwedenDegenerative Disease ProgramSanford-Burnham Medical Research Institute, Del E. Webb Neuroscience, Aging and Stem Cell Research Center, 10901 North Torrey Pines Road, La Jolla, California 92037, USADepartment of Biochemistry and Molecular BiologyCollege of Medicine, University of South Alabama, Mobile, Alabama 36688, USADepartment of Internal MedicineSödertälje Hospital, Södertälje, SwedenBiovation Park TelgeSödertälje, SwedenResearch UnitSödertälje Hospital, SE-152 86 Södertälje, SwedenDegenerative Disease ProgramSanford-Burnham Medical Research Institute, Del E. Webb Neuroscience, Aging and Stem Cell Research Center, 10901 North Torrey Pines Road, La Jolla, California 92037, USADepartment of Biochemistry and Molecular BiologyCollege of Medicine, University of South Alabama, Mobile, Alabama 36688, USADepartment of Internal MedicineSödertälje Hospital, Södertälje, Sweden
| |
Collapse
|
28
|
Patel R, Williams-Dautovich J, Cummins CL. Minireview: new molecular mediators of glucocorticoid receptor activity in metabolic tissues. Mol Endocrinol 2014; 28:999-1011. [PMID: 24766141 DOI: 10.1210/me.2014-1062] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The glucocorticoid receptor (GR) was one of the first nuclear hormone receptors cloned and represents one of the most effective drug targets available today for the treatment of severe inflammation. The physiologic consequences of endogenous or exogenous glucocorticoid excess are well established and include hyperglycemia, insulin resistance, fatty liver, obesity, and muscle wasting. However, at the molecular and tissue-specific level, there are still many unknown protein mediators of glucocorticoid response and thus, much remains to be uncovered that will help determine whether activation of the GR can be tailored to improve therapeutic efficacy while minimizing unwanted side effects. This review summarizes recent discoveries of tissue-selective modulators of glucocorticoid signaling that are important in mediating the unwanted side effects of therapeutic glucocorticoid use, emphasizing the downstream molecular effects of GR activation in the liver, adipose tissue, muscle, and pancreas.
Collapse
Affiliation(s)
- Rucha Patel
- Department of Pharmaceutical Sciences (R.P., J.W-D., C.L.C.), University of Toronto, Toronto, Ontario, M5S 3M2, Canada; and Banting and Best Diabetes Centre (C.L.C.), Toronto, Ontario M5G 2C4 Canada
| | | | | |
Collapse
|
29
|
Fransson L, Rosengren V, Saha TK, Grankvist N, Islam T, Honkanen RE, Sjöholm Å, Ortsäter H. Mitogen-activated protein kinases and protein phosphatase 5 mediate glucocorticoid-induced cytotoxicity in pancreatic islets and β-cells. Mol Cell Endocrinol 2014; 383:126-36. [PMID: 24361515 DOI: 10.1016/j.mce.2013.12.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [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: 06/18/2013] [Revised: 12/15/2013] [Accepted: 12/16/2013] [Indexed: 11/21/2022]
Abstract
Glucocorticoid excess is associated with glucose intolerance and diabetes. In addition to inducing insulin resistance, glucocorticoids impair β-cell function and cause β-cell apoptosis. In this study we show that dexamethasone activates mitogen-activated protein kinases (MAPKs) signaling in MIN6 β-cells, as evident by enhanced phosphorylation of p38 MAPK and c-Jun N-terminal kinase (JNK). In contrast, the integrated stress response pathway was inhibited by dexamethasone. A p38 MAPK inhibitor attenuated dexamethasone-induced apoptosis in β-cells and isolated islets and decreased glucocorticoid receptor phosphorylation at S220. In contrast, a JNK inhibitor augmented DNA fragmentation and dexamethasone-induced formation of cleaved caspase 3. We also show that inhibition of protein phosphatase 5 (PP5) augments apoptosis in dexamethasone-exposed islets and β-cells, with a concomitant activation of p38 MAPK. In conclusion, our data provide evidence that in islets and β-cells, p38 MAPK and JNK phosphorylation work in concert with PP5 to regulate the cytotoxic effects exerted by glucocorticoids.
Collapse
Affiliation(s)
- Liselotte Fransson
- Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet, Stockholm, Sweden
| | - Victoria Rosengren
- Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet, Stockholm, Sweden
| | - Titu Kumar Saha
- Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet, Stockholm, Sweden
| | - Nina Grankvist
- Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet, Stockholm, Sweden
| | - Tohidul Islam
- Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet, Stockholm, Sweden
| | - Richard E Honkanen
- Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet, Stockholm, Sweden; Department of Internal Medicine, Södertälje Hospital, SE 152 86 Södertälje, Sweden
| | - Åke Sjöholm
- Department of Internal Medicine, Södertälje Hospital, SE 152 86 Södertälje, Sweden; Department of Biochemistry and Molecular Biology, University of South Alabama, College of Medicine, Mobile, AL, USA
| | - Henrik Ortsäter
- Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet, Stockholm, Sweden; Research Unit, Södertälje Hospital, SE-152 86 Södertälje, Sweden.
| |
Collapse
|
30
|
Yoshihara E, Masaki S, Matsuo Y, Chen Z, Tian H, Yodoi J. Thioredoxin/Txnip: redoxisome, as a redox switch for the pathogenesis of diseases. Front Immunol 2014; 4:514. [PMID: 24409188 PMCID: PMC3885921 DOI: 10.3389/fimmu.2013.00514] [Citation(s) in RCA: 229] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 12/27/2013] [Indexed: 12/13/2022] Open
Abstract
During the past few decades, it has been widely recognized that Reduction-Oxidation (redox) responses occurring at the intra- and extra-cellular levels are one of most important biological phenomena and dysregulated redox responses are involved in the initiation and progression of multiple diseases. Thioredoxin1 (Trx1) and Thioredoxin2 (Trx2), mainly located in the cytoplasm and mitochondria, respectively, are ubiquitously expressed in variety of cells and control cellular reactive oxygen species by reducing the disulfides into thiol groups. Thioredoxin interacting protein (Txnip/thioredoxin binding protein-2/vitamin D3 upregulated protein) directly binds to Trx1 and Trx2 (Trx) and inhibit the reducing activity of Trx through their disulfide exchange. Recent studies have revealed that Trx1 and Txnip are involved in some critical redox-dependent signal pathways including NLRP-3 inflammasome activation in a redox-dependent manner. Therefore, Trx/Txnip, a redox-sensitive signaling complex is a regulator of cellular redox status and has emerged as a key component in the link between redox regulation and the pathogenesis of diseases. Here, we review the novel functional concept of the redox-related protein complex, named “Redoxisome,” consisting of Trx/Txnip, as a critical regulator for intra- and extra-cellular redox signaling, involved in the pathogenesis of various diseases such as cancer, autoimmune disease, and diabetes.
Collapse
Affiliation(s)
- Eiji Yoshihara
- Institute for Virus Research, Kyoto University , Kyoto , Japan
| | - So Masaki
- Institute for Virus Research, Kyoto University , Kyoto , Japan
| | | | - Zhe Chen
- Institute for Virus Research, Kyoto University , Kyoto , Japan
| | - Hai Tian
- Advanced Chemical Technology Center in Kyoto (ACT Kyoto), JBPA Research Institute , Kyoto , Japan ; Redox Bio Science Inc. , Kyoto , Japan
| | - Junji Yodoi
- Institute for Virus Research, Kyoto University , Kyoto , Japan ; Advanced Chemical Technology Center in Kyoto (ACT Kyoto), JBPA Research Institute , Kyoto , Japan ; Redox Bio Science Inc. , Kyoto , Japan
| |
Collapse
|
31
|
Abstract
In the past decades, glucocorticoid (GC) hormones and their cognate, intracellular receptor, the glucocorticoid receptor (GR), have been well established as critical checkpoints in mammalian energy homeostasis. Whereas many aspects in healthy nutrient metabolism require physiological levels and/or action of GC, aberrant GC/GR signalling has been linked to severe metabolic dysfunction, including obesity, insulin resistance and type 2 diabetes. Consequently, studies of the molecular mechanisms within the GC signalling axis have become a major focus in biomedical research, up-to-date particularly focusing on systemic glucose and lipid handling. However, with the availability of novel high throughput technologies and more sophisticated metabolic phenotyping capabilities, as-yet non-appreciated, metabolic functions of GC have been recently discovered, including regulatory roles of the GC/GR axis in protein and bile acid homeostasis as well as metabolic inter-organ communication. Therefore, this review summarises recent advances in GC/GR biology, and summarises findings relevant for basic and translational metabolic research.
Collapse
Affiliation(s)
- Adam J Rose
- Joint Research Division, Molecular Metabolic Control, German Cancer Research Center (DKFZ) Heidelberg, Center for Molecular Biology (ZMBH), Heidelberg University, Network Aging Research, University Hospital Heidelberg, Germany
| | | |
Collapse
|
32
|
Hanschmann EM, Godoy JR, Berndt C, Hudemann C, Lillig CH. Thioredoxins, glutaredoxins, and peroxiredoxins--molecular mechanisms and health significance: from cofactors to antioxidants to redox signaling. Antioxid Redox Signal 2013; 19:1539-605. [PMID: 23397885 PMCID: PMC3797455 DOI: 10.1089/ars.2012.4599] [Citation(s) in RCA: 489] [Impact Index Per Article: 44.5] [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] [Received: 03/05/2012] [Revised: 02/01/2013] [Accepted: 02/07/2013] [Indexed: 12/19/2022]
Abstract
Thioredoxins (Trxs), glutaredoxins (Grxs), and peroxiredoxins (Prxs) have been characterized as electron donors, guards of the intracellular redox state, and "antioxidants". Today, these redox catalysts are increasingly recognized for their specific role in redox signaling. The number of publications published on the functions of these proteins continues to increase exponentially. The field is experiencing an exciting transformation, from looking at a general redox homeostasis and the pathological oxidative stress model to realizing redox changes as a part of localized, rapid, specific, and reversible redox-regulated signaling events. This review summarizes the almost 50 years of research on these proteins, focusing primarily on data from vertebrates and mammals. The role of Trx fold proteins in redox signaling is discussed by looking at reaction mechanisms, reversible oxidative post-translational modifications of proteins, and characterized interaction partners. On the basis of this analysis, the specific regulatory functions are exemplified for the cellular processes of apoptosis, proliferation, and iron metabolism. The importance of Trxs, Grxs, and Prxs for human health is addressed in the second part of this review, that is, their potential impact and functions in different cell types, tissues, and various pathological conditions.
Collapse
Affiliation(s)
- Eva-Maria Hanschmann
- Institute for Medical Biochemistry and Molecular Biology, University Medicine, Ernst-Moritz Arndt University, Greifswald, Germany
| | - José Rodrigo Godoy
- Institute of Physiology, Pathophysiology and Biophysics, Department of Biomedical Sciences, University of Veterinary Medicine, Vienna, Austria
| | - Carsten Berndt
- Department of Neurology, Medical Faculty, Heinrich-Heine University, Duesseldorf, Germany
| | - Christoph Hudemann
- Institute of Laboratory Medicine, Molecular Diagnostics, Philipps University, Marburg, Germany
| | - Christopher Horst Lillig
- Institute for Medical Biochemistry and Molecular Biology, University Medicine, Ernst-Moritz Arndt University, Greifswald, Germany
| |
Collapse
|
33
|
Gowda N, Dandu A, Singh J, Biswas S, Raghav V, Lakshmi MN, Shilpa PC, Sunil V, Reddy A, Sadasivuni M, Aparna K, Verma MK, Moolemath Y, Anup MO, Venkataranganna MV, Somesh BP, Jagannath MR. Treatment with CNX-011-67, a novel GPR40 agonist, delays onset and progression of diabetes and improves beta cell preservation and function in male ZDF rats. BMC Pharmacol Toxicol 2013; 14:28. [PMID: 23692921 PMCID: PMC3668190 DOI: 10.1186/2050-6511-14-28] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Accepted: 05/15/2013] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The role of G protein-coupled receptor (GPR40), which is highly expressed in pancreatic beta cells, has been studied extensively in the amelioration of beta cell dysfunction in T2D using rat and mouse islets, beta cell lines and in animal models of diabetes. But its potential as a therapeutic target has not been fully explored. This aim of the study is to evaluate the therapeutic potential of CNX-011-67, a highly selective, potent and orally bioavailable GPR40 agonist, in controlling diabetes and other metabolic parameters. METHODS Seven week old male ZDF rats were treated with either vehicle or CNX-011-67, 5 mg/kg twice daily, for seven weeks. The animals were subjected to oral glucose tolerance and insulin tolerance tests. Plasma glucose, insulin, triglyceride, HbA1c, fructosamine and free fatty acids were measured at selected time points. Pancreas from control and treated animals were subjected to insulin and pancreatic and duodenal homeobox 1 (PDX1) immunohistochemistry and were also evaluated by electron microscopy. Also the potential impact of CNX-011-67 on islet insulin secretion, content, ATP levels and markers of both glucose oxidation, beta cell health in rat islets under chronic glucolipotoxic conditions was evaluated. RESULTS Treatment of male ZDF rats with CNX-011-67 for 7 weeks significantly enhanced insulin secretion in response to oral glucose load, delayed the onset of fasting hyperglycemia by 3 weeks, reduced nonfasting glucose excursions, fasting free fatty acids and triglyceride levels. A significant increase in PDX1 expression and insulin content and reduction in plasma fructosamine, HOMA-IR, and beta cell apoptosis were observed. CNX-011-67 improves glucose mediated insulin secretion, insulin gene transcription and islet insulin content in cultured rat islets under chronic glucolipotoxic condition. Also enhanced glucose oxidation in the form of increased islet ATP content and overall improvement in beta cell health in the form of reduced expression of stress markers (TXNIP and CHOP mRNA) were observed. CONCLUSIONS These findings, suggest that long-term oral therapy with CNX-011-67 could be of clinical value to provide good glycemic control and improve islet beta cell function.
Collapse
|
34
|
Filhoulaud G, Guilmeau S, Dentin R, Girard J, Postic C. Novel insights into ChREBP regulation and function. Trends Endocrinol Metab 2013; 24:257-68. [PMID: 23597489 DOI: 10.1016/j.tem.2013.01.003] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 12/23/2012] [Accepted: 01/03/2013] [Indexed: 12/17/2022]
Abstract
Glucose is an energy source that also controls the expression of key genes involved in energetic metabolism through the glucose-signaling transcription factor carbohydrate response element-binding protein (ChREBP). ChREBP has recently emerged as a central regulator of glycolysis and de novo fatty acid synthesis in liver, but new evidence shows that it plays a broader and crucial role in various processes, ranging from glucolipotoxicity to apoptosis and/or proliferation in specific cell types. However, several aspects of ChREBP activation by glucose metabolites are currently controversial, as well as the effects of activating or inhibiting ChREBP, on insulin sensitivity, which might depend on genetic, dietary or environmental factors. Thus, much remains to be elucidated. Here, we summarize our current understanding of the regulation and function of this fascinating transcription factor.
Collapse
|
35
|
Gruver-Yates AL, Cidlowski JA. Tissue-specific actions of glucocorticoids on apoptosis: a double-edged sword. Cells 2013; 2:202-23. [PMID: 24709697 PMCID: PMC3972684 DOI: 10.3390/cells2020202] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 03/05/2013] [Accepted: 03/12/2013] [Indexed: 12/20/2022] Open
Abstract
First described for their metabolic and immunosuppressive effects, glucocorticoids are widely prescribed in clinical settings of inflammation. However, glucocorticoids are also potent inducers of apoptosis in many cell types and tissues. This review will focus on the established mechanisms of glucocorticoid-induced apoptosis and outline what is known about the apoptotic response in cells and tissues of the body after exposure to glucocorticoids. Glucocorticoid-induced apoptosis affects the skeletal system, muscular system, circulatory system, nervous system, endocrine system, reproductive system, and the immune system. Interestingly, several cell types have an anti-apoptotic response to glucocorticoids that is cytoprotective. Lastly, we will discuss the pro- and anti-apoptotic effects of glucocorticoids in cancers and their clinical implications.
Collapse
Affiliation(s)
- Amanda L Gruver-Yates
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA.
| | - John A Cidlowski
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA.
| |
Collapse
|
36
|
Abstract
The initial response of lymphoid malignancies to glucocorticoids (GCs) is a critical parameter predicting successful treatment. Although being known as a strong inducer of apoptosis in lymphoid cells for almost a century, the signaling pathways regulating the susceptibility of the cells to GCs are only partly revealed. There is still a need to develop clinical tests that can predict the outcome of GC therapy. In this paper, I discuss important parameters modulating the pro-apoptotic effects of GCs, with a specific emphasis on the microRNA world comprised of small players with big impacts. The journey through the multifaceted complexity of GC-induced apoptosis brings forth explanations for the differential treatment response and raises potential strategies for overcoming drug resistance.
Collapse
Affiliation(s)
- Ronit Vogt Sionov
- The Department of Biochemistry and Molecular Biology, The Institute for Medical Research-Israel-Canada, Hadassah Medical School, The Hebrew University of Jerusalem, Ein-Kerem, 91120 Jerusalem, Israel
| |
Collapse
|
37
|
Cohen-Kutner M, Khomsky L, Trus M, Aisner Y, Niv MY, Benhar M, Atlas D. Thioredoxin-mimetic peptides (TXM) reverse auranofin induced apoptosis and restore insulin secretion in insulinoma cells. Biochem Pharmacol 2013; 85:977-90. [PMID: 23327993 DOI: 10.1016/j.bcp.2013.01.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [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: 11/28/2012] [Revised: 01/07/2013] [Accepted: 01/08/2013] [Indexed: 01/11/2023]
Abstract
The thioredoxin reductase/thioredoxin system (TrxR/Trx1) plays a major role in protecting cells from oxidative stress. Disruption of the TrxR-Trx1 system keeps Trx1 in the oxidized state leading to cell death through activation of the ASK1-Trx1 apoptotic pathway. The potential mechanism and ability of tri- and tetra-oligopeptides derived from the canonical -CxxC- motif of the Trx1-active site to mimic and enhance Trx1 cellular activity was examined. The Trx mimetics peptides (TXM) protected insulinoma INS 832/13 cells from oxidative stress induced by selectively inhibiting TrxR with auranofin (AuF). TXM reversed the AuF-effects preventing apoptosis, and increasing cell-viability. The TXM peptides were effective in inhibiting AuF-induced MAPK, JNK and p38(MAPK) phosphorylation, in correlation with preventing caspase-3 cleavage and thereby PARP-1 dissociation. The ability to form a disulfide-bridge-like conformation was estimated from molecular dynamics simulations. The TXM peptides restored insulin secretion and displayed Trx1 denitrosylase activity. Their potency was 10-100-fold higher than redox reagents like NAC, AD4, or ascorbic acid. Unable to reverse ERK1/2 phosphorylation, TXM-CB3 (NAc-Cys-Pro-Cys amide) appeared to function in part, through inhibiting ASK1-Trx dissociation. These highly effective anti-apoptotic effects of Trx1 mimetic peptides exhibited in INS 832/13 cells could become valuable in treating adverse oxidative-stress related disorders such as diabetes.
Collapse
Affiliation(s)
- Moshe Cohen-Kutner
- Department of Biological Chemistry, The Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 919104, Israel
| | | | | | | | | | | | | |
Collapse
|
38
|
Abstract
Chronic hyperglycemia (HG)-associated reactive oxygen/nitrogen species (ROS/RNS) stress and low grade inflammation are considered to play critical roles in the development of diabetic retinopathy (DR). Excess glucose metabolic flux through the aldose reductase/polyol pathway, advanced glycation end product (AGE) formation, elevated hexosamine biosynthesis pathway (HBP), diacyl glycerol/PKC activation, and mitochondrial ROS generation are all implicated in DR. In addition, endoplasmic reticulum stress/unfolded protein response (er-UPR) and deregulation of mitochondrial quality control by autophagy/mitophagy are observed causing cellular bioenergetic deficiency and injury. Recently, a pro-oxidant and pro-apoptotic thioredoxin interacting protein (TXNIP) was shown to be highly upregulated in DR and by HG in retinal cells in culture. TXNIP binds to thioredoxin (Trx) inhibiting its oxidant scavenging and thiolreducing capacity. Hence, prolonged overexpression of TXNIP causes ROS/RNS stress, mitochondrial dysfunction, inflammation and premature cell death in DR. Initially, DR was considered as microvascular complications of endothelial dysfunction and pericyte loss characterized by capillary basement membrane thickening, pericyte ghost, blood retinal barrier leakage, acellular capillary and neovascularization. However, it is currently acknowledged that neuro-glia are also affected by HG in diabetes and that neuronal injury, glial activation, innate immunity/sterile inflammation, and ganglion apoptosis occur early in DR. In addition, retinal pigment epithelium (RPE) becomes dysfunctional in DR. Since TXNIP is induced by HG in most cells, its effects are not restricted to a particular cell type in DR. However, depending on the metabolic activity and anti-oxidant capacity, some cells may be affected earlier by TXNIP than others. Identification of TXNIP sensitive cells and elucidating the underlying mechanism(s) will be critical for preventing pre-mature cell death and progression of DR.
Collapse
Affiliation(s)
- Lalit P Singh
- Departments of Anatomy and Cell Biology and Ophthalmology, Wayne State University School of Medicine, Detroit, MI 48201, USA
| |
Collapse
|