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Suppression of Lipid Accumulation in the Differentiation of 3T3-L1 Preadipocytes and Human Adipose Stem Cells into Adipocytes by TAK-715, a Specific Inhibitor of p38 MAPK. Life (Basel) 2023; 13:life13020412. [PMID: 36836769 PMCID: PMC9965126 DOI: 10.3390/life13020412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/20/2023] [Accepted: 01/29/2023] [Indexed: 02/05/2023] Open
Abstract
Excessive preadipocyte differentiation is linked with obesity. Although previous studies have shown that p38 MAPK is associated with adipogenesis, the regulation of preadipocyte differentiation by TAK-715, an inhibitor of p38 mitogen-activated protein kinase (MAPK), remains unclear. Interestingly, TAK-715 at 10 μM vastly suppressed the accumulation of lipid and intracellular triglyceride (TG) content with no cytotoxicity during 3T3-L1 preadipocyte differentiation. On mechanistic levels, TAK-715 significantly decreased the expressions of the CCAAT/enhancer-binding protein-α (C/EBP-α), peroxisome proliferator-activated receptor gamma (PPAR-γ), fatty acid synthase (FAS), and perilipin A. Similarly, the phosphorylation of the signal transducer and activator of transcription-3 (STAT-3) in differentiating 3T3-L1 cells was also reduced with TAK-715 treatment. Moreover, TAK-715 significantly blocked the phosphorylation of activating transcription factor-2 (ATF-2), a p38 MAPK downstream molecule, during 3T3-L1 preadipocyte differentiation. Of importance, TAK-715 also markedly impeded the phosphorylation of p38 MAPK and suppressed lipid accumulation during the adipocyte differentiation of human adipose stem cells (hASCs). Concisely, this is the first report that TAK-715 (10 μM) has potent anti-adipogenic effects on the adipogenesis process of 3T3-L1 cells and hASCs through the regulation of the expression and phosphorylation of p38 MAPK, C/EBP-α, PPAR-γ, STAT-3, FAS, and perilipin A.
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Chen M, Liu Y, Yang Y, Qiu Y, Wang Z, Li X, Zhang W. Emerging roles of activating transcription factor (ATF) family members in tumourigenesis and immunity: Implications in cancer immunotherapy. Genes Dis 2022; 9:981-999. [PMID: 35685455 PMCID: PMC9170601 DOI: 10.1016/j.gendis.2021.04.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 04/20/2021] [Accepted: 04/26/2021] [Indexed: 12/12/2022] Open
Abstract
Activating transcription factors, ATFs, are a group of bZIP transcription factors that act as homodimers or heterodimers with a range of other bZIP factors. In general, ATFs respond to extracellular signals, indicating their important roles in maintaining homeostasis. The ATF family includes ATF1, ATF2, ATF3, ATF4, ATF5, ATF6, and ATF7. Consistent with the diversity of cellular processes reported to be regulated by ATFs, the functions of ATFs are also diverse. ATFs play an important role in cell proliferation, apoptosis, differentiation and inflammation-related pathological processes. The expression and phosphorylation status of ATFs are also related to neurodegenerative diseases and polycystic kidney disease. Various miRNAs target ATFs to regulate cancer proliferation, apoptosis, autophagy, sensitivity and resistance to radiotherapy and chemotherapy. Moreover, ATFs are necessary to maintain cell redox homeostasis. Therefore, deepening our understanding of the regulation and function of ATFs will provide insights into the basic regulatory mechanisms that influence how cells integrate extracellular and intracellular signals into genomic responses through transcription factors. Under pathological conditions, especially in cancer biology and response to treatment, the characterization of ATF dysfunction is important for understanding how to therapeutically utilize ATF2 or other pathways controlled by transcription factors. In this review, we will demonstrate how ATF1, ATF2, ATF3, ATF4, ATF5, ATF6, and ATF7 function in promoting or suppressing cancer development and identify their roles in tumour immunotherapy.
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Affiliation(s)
| | | | | | | | | | | | - Wenling Zhang
- Corresponding author. Department of Medical Laboratory Science, the Third Xiangya Hospital, Central South University, Tongzipo Road 172, Yuelu District, Changsha, Hunan 410013, PR China.
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Low HB, Wong ZL, Wu B, Kong LR, Png CW, Cho YL, Li CW, Xiao F, Xin X, Yang H, Loo JM, Lee FYX, Tan IBH, DasGupta R, Shen HM, Schwarz H, Gascoigne NRJ, Goh BC, Xu X, Zhang Y. DUSP16 promotes cancer chemoresistance through regulation of mitochondria-mediated cell death. Nat Commun 2021; 12:2284. [PMID: 33863904 PMCID: PMC8052345 DOI: 10.1038/s41467-021-22638-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 03/18/2021] [Indexed: 02/02/2023] Open
Abstract
Drug resistance is a major obstacle to the treatment of most human tumors. In this study, we find that dual-specificity phosphatase 16 (DUSP16) regulates resistance to chemotherapy in nasopharyngeal carcinoma, colorectal cancer, gastric and breast cancer. Cancer cells expressing higher DUSP16 are intrinsically more resistant to chemotherapy-induced cell death than cells with lower DUSP16 expression. Overexpression of DUSP16 in cancer cells leads to increased resistance to cell death upon chemotherapy treatment. In contrast, knockdown of DUSP16 in cancer cells increases their sensitivity to treatment. Mechanistically, DUSP16 inhibits JNK and p38 activation, thereby reducing BAX accumulation in mitochondria to reduce apoptosis. Analysis of patient survival in head & neck cancer and breast cancer patient cohorts supports DUSP16 as a marker for sensitivity to chemotherapy and therapeutic outcome. This study therefore identifies DUSP16 as a prognostic marker for the efficacy of chemotherapy, and as a therapeutic target for overcoming chemoresistance in cancer.
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Affiliation(s)
- Heng Boon Low
- grid.4280.e0000 0001 2180 6431Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore ,grid.4280.e0000 0001 2180 6431Immunology Programme, the Life Science Institute, National University of Singapore, Singapore, Singapore
| | - Zhen Lim Wong
- grid.4280.e0000 0001 2180 6431Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore ,grid.4280.e0000 0001 2180 6431Immunology Programme, the Life Science Institute, National University of Singapore, Singapore, Singapore
| | - Bangyuan Wu
- grid.4280.e0000 0001 2180 6431Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore ,grid.4280.e0000 0001 2180 6431Immunology Programme, the Life Science Institute, National University of Singapore, Singapore, Singapore ,grid.411527.40000 0004 0610 111XCollege of Life Science, China West Normal University, Nanchong, Sichuan China
| | - Li Ren Kong
- grid.4280.e0000 0001 2180 6431Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Chin Wen Png
- grid.4280.e0000 0001 2180 6431Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore ,grid.4280.e0000 0001 2180 6431Immunology Programme, the Life Science Institute, National University of Singapore, Singapore, Singapore
| | - Yik-Lam Cho
- grid.4280.e0000 0001 2180 6431Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Chun-Wei Li
- grid.412615.5Department of Otorhinolaryngology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Fengchun Xiao
- grid.417400.60000 0004 1799 0055Department of Pathology, The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, China
| | - Xuan Xin
- grid.4280.e0000 0001 2180 6431Department of Mathematics, National University of Singapore, Singapore, Singapore
| | - Henry Yang
- grid.4280.e0000 0001 2180 6431Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Jia Min Loo
- grid.418377.e0000 0004 0620 715XGenome Institute of Singapore, Agency of Science Technology and Research (A*Star), Singapore, Singapore
| | - Fiona Yi Xin Lee
- grid.410724.40000 0004 0620 9745Division of Medical Oncology, National Cancer Center, Singapore, Singapore
| | - Iain Bee Huat Tan
- grid.410724.40000 0004 0620 9745Division of Medical Oncology, National Cancer Center, Singapore, Singapore
| | - Ramanuj DasGupta
- grid.418377.e0000 0004 0620 715XGenome Institute of Singapore, Agency of Science Technology and Research (A*Star), Singapore, Singapore
| | - Han-Ming Shen
- grid.4280.e0000 0001 2180 6431Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore ,grid.437123.00000 0004 1794 8068Faculty of Health Sciences, University of Macau, Macau, China
| | - Herbert Schwarz
- grid.4280.e0000 0001 2180 6431Immunology Programme, the Life Science Institute, National University of Singapore, Singapore, Singapore ,grid.4280.e0000 0001 2180 6431Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Nicholas R. J. Gascoigne
- grid.4280.e0000 0001 2180 6431Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore ,grid.4280.e0000 0001 2180 6431Immunology Programme, the Life Science Institute, National University of Singapore, Singapore, Singapore
| | - Boon Cher Goh
- grid.4280.e0000 0001 2180 6431Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore ,grid.440782.d0000 0004 0507 018XDepartment of Haematology-Oncology, National University Cancer Institute, Singapore, Singapore ,grid.4280.e0000 0001 2180 6431Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Xiaohong Xu
- grid.417400.60000 0004 1799 0055Department of Breast Surgery, The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, China
| | - Yongliang Zhang
- grid.4280.e0000 0001 2180 6431Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore ,grid.4280.e0000 0001 2180 6431Immunology Programme, the Life Science Institute, National University of Singapore, Singapore, Singapore
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Ma Y, Song Y, Li L, Dong L, Wang C, Wang P, Yang L. Mechano growth factor pretreatment yield mechanical stimuli induced cell stress responses in ligament fibroblasts of osteoarthritis via activating ATF-2. Biotechnol Lett 2020; 42:1337-1349. [PMID: 32222864 DOI: 10.1007/s10529-020-02866-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Accepted: 12/09/2019] [Indexed: 01/05/2023]
Abstract
OBJECTIVE The purpose of this study is to investigate whether mechanical growth factor (MGF) promotes mechanical response to ligament fibroblasts in osteoarthritis knee cavity via activating transcription factor 2 (ATF-2). RESULTS Osteoarthritis ligament fibroblasts (OA-LFs) were suffered from 12% static mechanical stretch to mimic mechanical force mediated ligament injury. Meanwhile, OA-LFs were treated with MGF before and during mechanical stretch. We observed that OA delayed LFs response to mechanical injury, while MGF pretreatment promoted cells timely feedback the mechanically stimuli by inducing cellular stress. Additionally, MGF accelerated the ligament injury repair by promoting cell migration, decreasing the MMP-2 activity, and remitting the cell deformation via ATF-2 activating in cells. CONCLUSIONS Our study shows that MGF pretreatment of OA-LFs can respond quickly to mechanical damage and repair ligament tissue by activating ATF-2. Therefore, MGF has potential as a therapeutic for OA patients.
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Affiliation(s)
- Yu Ma
- '111' Project Laboratory of Biomechanics and Tissue Repair, Bioengineering College, Chongqing University, Chongqing, 400044, China
| | - Yang Song
- '111' Project Laboratory of Biomechanics and Tissue Repair, Bioengineering College, Chongqing University, Chongqing, 400044, China. .,Department of Bioengineering, University of California Los Angeles, Los Angeles, 90095, USA.
| | - Linhao Li
- Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, 100083, China.,Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China
| | - Lili Dong
- '111' Project Laboratory of Biomechanics and Tissue Repair, Bioengineering College, Chongqing University, Chongqing, 400044, China
| | - Chunli Wang
- '111' Project Laboratory of Biomechanics and Tissue Repair, Bioengineering College, Chongqing University, Chongqing, 400044, China
| | - Pingping Wang
- Department of Bioengineering, University of California Los Angeles, Los Angeles, 90095, USA. .,Beijing Key Laboratory of Bioelectromagnetism, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, 100190, China.
| | - Li Yang
- '111' Project Laboratory of Biomechanics and Tissue Repair, Bioengineering College, Chongqing University, Chongqing, 400044, China. .,Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, 100083, China.
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Zhang D, Shi R, Xiang W, Kang X, Tang B, Li C, Gao L, Zhang X, Zhang L, Dai R, Miao H. The Agpat4/LPA axis in colorectal cancer cells regulates antitumor responses via p38/p65 signaling in macrophages. Signal Transduct Target Ther 2020; 5:24. [PMID: 32296017 PMCID: PMC7099097 DOI: 10.1038/s41392-020-0117-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 12/23/2019] [Accepted: 01/06/2020] [Indexed: 12/23/2022] Open
Abstract
Lipid metabolic reprogramming plays an essential role in regulating the progression of colorectal cancer (CRC). However, the effect of lysophosphatidic acid (LPA) metabolism on CRC development is incompletely characterized. Here, we compared the mRNA levels of human CRC tissues to those of paracarcinoma tissues and focused on the notably enriched LPA metabolic pathways. We identified and verified that 1-acylglycerol-3-phosphate O-acyltransferase 4 (Agpat4) was aberrantly expressed in CRC tissues and predicted poor survival in CRC patients. Manipulating Agpat4 expression in CRC cells did not affect the growth or migration of CRC cells in vitro, whereas Agpat4 silencing suppressed CRC cell growth in subcutaneous and peritoneal xenograft models. Mechanistically, Agpat4 silencing-induced LPA release from CRC cells and polarized macrophages to an M1-like phenotype through LPA receptors 1 and 3. This M1 activation, characterized by elevated p38/p65 signaling and increased proinflammatory cytokines, promoted the infiltration and activation of CD4+ and CD8+ T cells in the tumor microenvironment. Modulation of the Agpat4/LPA/p38/p65 axis regulated macrophage polarization, T-cell activity and CRC progression. Notably, combined therapy with LPA and regular chemotherapy drugs synergistically suppressed CRC development. Taken together, our results showed that the Agpat4/LPA axis in CRC cells regulated p38/p65 signaling-dependent macrophage polarization, T-cell activation, and CRC progression. The Agpat4/LPA/p38/p65 axis might represent a potential target for therapy in the clinic.
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Affiliation(s)
- Dapeng Zhang
- Department of Biochemistry and Molecular Biology, Southwest Medical University, Luzhou, 646000, China.,Department of Biochemistry and Molecular Biology, Third Military Medical University (Army Medical University), Chongqing, 400038, China
| | - Rongchen Shi
- Department of Biochemistry and Molecular Biology, Third Military Medical University (Army Medical University), Chongqing, 400038, China
| | - Wei Xiang
- Department of Biochemistry and Molecular Biology, Third Military Medical University (Army Medical University), Chongqing, 400038, China
| | - Xia Kang
- Department of Biochemistry and Molecular Biology, Third Military Medical University (Army Medical University), Chongqing, 400038, China
| | - Bo Tang
- Department of General Surgery, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China
| | - Chuan Li
- Department of General Surgery, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China
| | - Linfeng Gao
- Department of General Surgery, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China
| | - Xuan Zhang
- Department of Oncology, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China
| | - Lili Zhang
- Department of Military Psychology, School of Psychology, Third Military Medical University (Army Medical University), Chongqing, 400038, China
| | - Rongyang Dai
- Department of Biochemistry and Molecular Biology, Southwest Medical University, Luzhou, 646000, China.
| | - Hongming Miao
- Department of Biochemistry and Molecular Biology, Southwest Medical University, Luzhou, 646000, China. .,Department of Biochemistry and Molecular Biology, Third Military Medical University (Army Medical University), Chongqing, 400038, China.
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6
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Li X, Fan K, Li Q, Pan D, Hai R, Du C. Melanocortin 4 receptor-mediated effects of amylin on thermogenesis and regulation of food intake. Diabetes Metab Res Rev 2019; 35:e3149. [PMID: 30851142 DOI: 10.1002/dmrr.3149] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 03/02/2019] [Accepted: 03/05/2019] [Indexed: 02/02/2023]
Abstract
AIMS Amylin, a pancreatic hormone cosecreted with insulin, exerts important anorexic and weight-loss effects. Melanocortin 4 receptor (MC4R) signalling plays a critical role in energy homeostasis; however, its role on amylin-dependent regulation of food intake and adaptive thermogenesis of interscapular brown adipose tissue (IBAT) are unclear. In this study, we examined the effects of amylin on food intake and thermogenesis on IBAT via the MC4R pathway in mice. MATERIALS AND METHODS Acute food consumption and thermogenesis in IBAT were measured in male wild-type (WT) and MC4R-deficient mice following intraperitoneal injection of amylin and SHU9119, an MC3R/4R antagonist, to determine the role of the central melanocortin system on the hypothalamus and IBAT. RESULTS Amylin (50 μg/kg) suppressed feeding and stimulated thermogenesis on IBAT via activation of the MC4R system in mice. Pharmacological blockade of MC4R using SHU9119 (50 μg/kg) attenuated amylin-induced inhibition of feeding and stimulation of thermogenesis in IBAT. No changes were observed when SHU9119 was injected alone. Moreover, amylin significantly increased MC4R expression and c-Fos neuronal signals in the arcuate nucleus and significantly increased acetyl-CoA carboxylase (ACC) phosphorylation in the hypothalamus and IBAT and uncoupling protein-1 (UCP1) expression in the IBAT of WT mice via the MC4R pathway. CONCLUSION The melanocortin system was involved in amylin-induced suppression of food intake and activation of thermogenesis in both the hypothalamus and IBAT via modulation of ACC phosphorylation and UCP1 expression.
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Affiliation(s)
- Xiaojing Li
- College of Agronomy, Inner Mongolia Agricultural University, Hohhot, China
| | - Kuikui Fan
- College of Veterinary Medicine, Inner Mongolia Agricultural University, Hohhot, China
| | - Qiang Li
- College of Veterinary Medicine, Inner Mongolia Agricultural University, Hohhot, China
| | - Deng Pan
- College of Veterinary Medicine, Inner Mongolia Agricultural University, Hohhot, China
| | - Rihan Hai
- Vocational and Technical College, Inner Mongolia Agricultural University, Baotou, China
| | - Chenguang Du
- College of Veterinary Medicine, Inner Mongolia Agricultural University, Hohhot, China
- Vocational and Technical College, Inner Mongolia Agricultural University, Baotou, China
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Watson G, Ronai ZA, Lau E. ATF2, a paradigm of the multifaceted regulation of transcription factors in biology and disease. Pharmacol Res 2017; 119:347-357. [PMID: 28212892 PMCID: PMC5457671 DOI: 10.1016/j.phrs.2017.02.004] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 02/01/2017] [Accepted: 02/02/2017] [Indexed: 01/16/2023]
Abstract
Stringent transcriptional regulation is crucial for normal cellular biology and organismal development. Perturbations in the proper regulation of transcription factors can result in numerous pathologies, including cancer. Thus, understanding how transcription factors are regulated and how they are dysregulated in disease states is key to the therapeutic targeting of these factors and/or the pathways that they regulate. Activating transcription factor 2 (ATF2) has been studied in a number of developmental and pathological conditions. Recent findings have shed light on the transcriptional, post-transcriptional, and post-translational regulatory mechanisms that influence ATF2 function, and thus, the transcriptional programs coordinated by ATF2. Given our current knowledge of its multiple levels of regulation and function, ATF2 represents a paradigm for the mechanistic complexity that can regulate transcription factor function. Thus, increasing our understanding of the regulation and function of ATF2 will provide insights into fundamental regulatory mechanisms that influence how cells integrate extracellular and intracellular signals into a genomic response through transcription factors. Characterization of ATF2 dysfunction in the context of pathological conditions, particularly in cancer biology and response to therapy, will be important in understanding how pathways controlled by ATF2 or other transcription factors might be therapeutically exploited. In this review, we provide an overview of the currently known upstream regulators and downstream targets of ATF2.
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Affiliation(s)
- Gregory Watson
- Department of Tumor Biology and Program in Chemical Biology and Molecular Medicine, H. Lee Moffitt Cancer Center, Tampa, FL, USA
| | - Ze'ev A Ronai
- Tumor Initiation and Maintenance Program, Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA; Technion Integrated Cancer Center, Rappaport Faculty of Medicine, Technion, Haifa, 3109601, Israel
| | - Eric Lau
- Department of Tumor Biology and Program in Chemical Biology and Molecular Medicine, H. Lee Moffitt Cancer Center, Tampa, FL, USA.
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Koturbash I, Jadavji NM, Kutanzi K, Rodriguez-Juarez R, Kogosov D, Metz GA, Kovalchuk O. Fractionated low-dose exposure to ionizing radiation leads to DNA damage, epigenetic dysregulation, and behavioral impairment. ENVIRONMENTAL EPIGENETICS 2016; 2:dvw025. [PMID: 29492301 PMCID: PMC5804539 DOI: 10.1093/eep/dvw025] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 10/25/2016] [Accepted: 10/27/2016] [Indexed: 05/04/2023]
Abstract
Studies of Fractionated Exposure to Low Doses of Ionizing Radiation (FELDIR) has become of increasing importance to clinical interventions. Its consequences on DNA damage, physical, and mental health have been insufficiently investigated, however. The goal of this study was to determine the effects of FELDIR on the brain using a mouse model. We addressed the levels of DNA damage, global genomic methylation, and DNA methylation machinery in cerebellum, frontal lobe, olfactory bulb and hippocampal tissues, as well as behavioral changes linked to FELDIR exposure. The results reveal increased levels of DNA damage, as reflected by increased occurrence of DNA Strand Breaks (SBs) and dysregulation of stress-response kinase p38. FELDIR also resulted in initial loss of global genomic methylation and altered expression of methyltransferases DNMT1 (down-regulation) and DNMT3a (up-regulation), as well as methyl-binding protein MeCP2 (up-regulation). FELDIR-associated behavioral changes included impaired skilled limb placement on a ladder rung task, increased rearing activity in an open field, and elevated anxiety-like behaviors. The said alterations showed significant dose and tissue specificity. Thus, FELDIR represents a critical impact on DNA integrity and behavioral outcomes that need to be considered in the design of clinical intervention studies.
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Affiliation(s)
- Igor Koturbash
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB, Canada T1K3M4
| | - Nafisa M. Jadavji
- Department of Neuroscience, University of Lethbridge, Lethbridge, AB, Canada T1K3M4
| | - Kristy Kutanzi
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB, Canada T1K3M4
| | - Rocio Rodriguez-Juarez
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB, Canada T1K3M4
| | - Dmitry Kogosov
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB, Canada T1K3M4
| | - Gerlinde A.S. Metz
- Department of Neuroscience, University of Lethbridge, Lethbridge, AB, Canada T1K3M4
- Alberta Epigenetics Network, Calgary, AB, Canada
| | - Olga Kovalchuk
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB, Canada T1K3M4
- Alberta Epigenetics Network, Calgary, AB, Canada
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9
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Zhang S, Liu H, Chuang CL, Li X, Au M, Zhang L, Phillips ARJ, Scott DW, Cooper GJS. The pathogenic mechanism of diabetes varies with the degree of overexpression and oligomerization of human amylin in the pancreatic islet β cells. FASEB J 2014; 28:5083-96. [PMID: 25138158 DOI: 10.1096/fj.14-251744] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The aggregation of human amylin (hA) to form cytotoxic structures has been closely associated with the causation of type 2 diabetes. We sought to advance understanding of how altered expression and aggregation of hA might link β-cell degeneration with diabetes onset and progression, by comparing phenotypes between homozygous and hemizygous hA-transgenic mice. The homozygous mice displayed elevated islet hA that correlated positively with measures of oligomer formation (r=0.91; P<0.0001). They also developed hyperinsulinemia with transient insulin resistance during the prediabetes stage and then underwent rapid β-cell loss, culminating in severe juvenile-onset diabetes. The prediabetes stage was prolonged in the hemizygous mice, wherein β-cell dysfunction and extensive oligomer formation occurred in adulthood at a much later stage, when hA levels were lower (r=-0.60; P<0.0001). This is the first report to show that hA-evoked diabetes is associated with age, insulin resistance, progressive islet dysfunction, and β-cell apoptosis, which interact variably to cause the different diabetes syndromes. The various levels of hA elevation cause different extents of oligomer formation in the disease stages, thus eliciting early- or adult-onset diabetes syndromes, reminiscent of type 1 and 2 diabetes, respectively. Thus, the hA-evoked diabetes phenotypes differ substantively according to degree of amylin overproduction. These findings are relevant to the understanding of the pathogenesis and the development of experimental therapeutics for diabetes.
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Affiliation(s)
- Shaoping Zhang
- The School of Biological Sciences and The Maurice Wilkins Centre for Molecular BioDiscovery, Faculty of Science, University of Auckland, Auckland, New Zealand
| | - Hong Liu
- The School of Biological Sciences and
| | | | | | - Maggie Au
- The School of Biological Sciences and
| | - Lin Zhang
- The School of Biological Sciences and
| | - Anthony R J Phillips
- The School of Biological Sciences and The Maurice Wilkins Centre for Molecular BioDiscovery, Faculty of Science, University of Auckland, Auckland, New Zealand
| | | | - Garth J S Cooper
- The School of Biological Sciences and The Maurice Wilkins Centre for Molecular BioDiscovery, Faculty of Science, University of Auckland, Auckland, New Zealand Centre for Advanced Discovery and Experimental Therapeutics, Central Manchester University Hospitals National Health Service (NHS) Foundation Trust, Manchester, UK; and Centre for Endocrinology and Diabetes, Institute of Human Development, Faculty of Medical and Human Sciences, Manchester Academic Health Sciences Centre, The University of Manchester, Manchester, UK
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10
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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] [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.
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Affiliation(s)
- Moshe Cohen-Kutner
- Department of Biological Chemistry, The Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 919104, Israel
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11
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Lang F, Ullrich S, Gulbins E. Ceramide formation as a target in beta-cell survival and function. Expert Opin Ther Targets 2011; 15:1061-71. [PMID: 21635197 DOI: 10.1517/14728222.2011.588209] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
INTRODUCTION Ceramide may be synthesized de novo or generated by sphingomyelinase-dependent hydrolysis of sphingomyelin. AREAS COVERED The role of ceramide, ceramide-sensitive signaling and ion channels in β-cell apoptosis, lipotoxicity and amyloid-induced β-cell death. EXPERT OPINION Ceramide participates in β-cell dysfunction and apoptosis after exposure to TNFα, IL-1β and IFN-γ, excessive amyloid and islet amyloid polypeptide or non-esterified fatty acids (lipotoxicity). Knockout of sphingomyelin synthase 1, which converts ceramide to sphingomyelin, leads to impairment of insulin secretion. Increased ceramidase activity or pharmacological inhibition of ceramide synthetase, inhibits β-cell apoptosis. Ceramide contributes to endoplasmatic reticulum (ER) stress, decreased mitochondrial membrane potential in insulin-secreting cells and mitochondrial release of cytochrome c into the cytosol, which are all triggers of apoptotic cell death. Ceramide-dependent signaling involves activation of extracellularly regulated kinases 1 and 2 (ERK1/2), downregulation of Period (Per)-aryl hydrocarbon receptor nuclear translocator (Arnt)-single-minded (Sim) kinase (PASK), activation of okadaic-acid-sensitive protein phosphatase 2A (PP2A) and stimulation of NADPH-oxidase with generation of superoxides and lipid peroxides. Ceramide reduces the activity of voltage gated potassium (Kv)-channels in insulin-secreting cells. The role of ceramide in β-cell survival and function may be therapeutically relevant, because ceramide formation can be suppressed by pharmacological inhibition of ceramide synthetase and/or sphingomyelinase.
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Affiliation(s)
- Florian Lang
- University of Tübingen, Institute of Physiology, Germany.
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12
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Ribas VT, Arruda-Carvalho M, Linden R, Chiarini LB. Early c-Jun N-terminal kinase-dependent phosphorylation of activating transcription factor-2 is associated with degeneration of retinal ganglion cells. Neuroscience 2011; 180:64-74. [PMID: 21300140 DOI: 10.1016/j.neuroscience.2011.01.059] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Revised: 01/24/2011] [Accepted: 01/26/2011] [Indexed: 12/12/2022]
Abstract
Neuron death due to deprivation of target-derived neurotrophic factors depends on protein synthesis regulated by transcription factor activity. We investigated the content and phosphorylation of activating transcription factor 2 (ATF-2) in axon-damaged retinal ganglion cells of neonatal rats. In the retina of neonatal rats, the ATF-2 protein is predominantly located in the nucleus of the ganglion cells. A gradual loss of the immunoreactivity for ATF-2 occurred after explantation. ATF-2 is phosphorylated early after explantation, with a peak within 3 hours, preceding the peak of cell death that occurs at 18 hours. Both the phosphorylation of ATF-2 and ganglion cell death were blocked by treatment with an inhibitor of c-Jun N-terminal kinase (JNK), whereas an inhibitor of p38 reduced only slightly the rate of ganglion cell death with no effect upon phosphorylation of ATF-2. Inhibitors of phosphatidyl inositol 3 kinase (PI-3K), protein kinase C (PKC) or extracellular regulated kinase (ERK) had no effect. Finally, the inhibitor of JNK blocked the upregulation of both c-Jun and Hrk in the GCL after retinal explantation. The data show that phosphorylation of ATF-2 by JNK is associated with retinal ganglion cell death after axon damage.
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Affiliation(s)
- V T Ribas
- Instituto de Biofísica Carlos Chagas Filho, UFRJ, Rio de Janeiro, Brasil
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13
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The chaperone proteins HSP70, HSP40/DnaJ and GRP78/BiP suppress misfolding and formation of β-sheet-containing aggregates by human amylin: a potential role for defective chaperone biology in Type 2 diabetes. Biochem J 2010; 432:113-21. [PMID: 20735358 DOI: 10.1042/bj20100434] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Misfolding of the islet β-cell peptide hA (human amylin) into β-sheet-containing oligomers is linked to β-cell apoptosis and the pathogenesis of T2DM (Type 2 diabetes mellitus). In the present study, we have investigated the possible effects on hA misfolding of the chaperones HSP (heat-shock protein) 70, GRP78/BiP (glucose-regulated protein of 78 kDa/immunoglobulin heavy-chain-binding protein) and HSP40/DnaJ. We demonstrate that hA underwent spontaneous time-dependent β-sheet formation and aggregation by thioflavin-T fluorescence in solution, whereas rA (rat amylin) did not. HSP70, GRP78/BiP and HSP40/DnaJ each independently suppressed hA misfolding. Maximal molar protein/hA ratios at which chaperone activity was detected were 1:200 (HSP70, HSP40/DnaJ and GRP78/BiP). By contrast, none of the chaperones modified the secondary structure of rA. hA, but not rA, was co-precipitated independently with HSP70 and GRP78/BiP by anti-amylin antibodies. As these effects occur at molar ratios consistent with chaperone binding to relatively rare misfolded hA species, we conclude that HSP70 and GRP78/BiP can detect and bind misfolded hA oligomers, thereby effectively protecting hA against bulk misfolding and irreversible aggregation. Defective β-cell chaperone biology could contribute to hA misfolding and initiation of apoptosis in T2DM.
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Zraika S, Hull RL, Verchere CB, Clark A, Potter KJ, Fraser PE, Raleigh DP, Kahn SE. Toxic oligomers and islet beta cell death: guilty by association or convicted by circumstantial evidence? Diabetologia 2010; 53:1046-56. [PMID: 20182863 PMCID: PMC3164873 DOI: 10.1007/s00125-010-1671-6] [Citation(s) in RCA: 144] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2009] [Accepted: 12/04/2009] [Indexed: 12/31/2022]
Abstract
Type 2 diabetes is a progressive disease characterised by islet amyloid deposits in the majority of patients. Amyloid formation is considered a significant factor in deterioration of islet function and reduction in beta cell mass, and involves aggregation of monomers of the normally soluble beta cell peptide, human islet amyloid polypeptide (hIAPP) into oligomers, fibrils and, ultimately, mature amyloid deposits. Despite extensive in vitro studies, the process of hIAPP aggregation in vivo is poorly understood, though it is widely reported to promote cytotoxicity. Recently, studies have suggested that only the early stages of fibril assembly, and in particular small hIAPP oligomers, are responsible for beta cell cytotoxicity. This challenges the prior concept that newly formed fibrils and/or mature fibrillar amyloid are cytotoxic. Herein, evidence both for and against the toxic hIAPP oligomer hypothesis is presented; from this, it is apparent that what exactly causes beta cell death when hIAPP aggregates remains debatable. Moreover, substantially more work with more specific reagents and techniques than are currently available will be required to identify conclusively the toxic species resulting from hIAPP aggregation. Keeping an open mind on the nature of the cytotoxic insult has implications for therapeutic developments and clinical care in type 2 diabetes.
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Affiliation(s)
- S Zraika
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, VA Puget Sound Health Care System and University of Washington, 1660 South Columbian Way (151), Seattle, WA 98108, USA.
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15
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Cooper GJS, Aitken JF, Zhang S. Is type 2 diabetes an amyloidosis and does it really matter (to patients)? Diabetologia 2010; 53:1011-6. [PMID: 20229094 DOI: 10.1007/s00125-010-1715-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2010] [Accepted: 02/10/2010] [Indexed: 12/17/2022]
Affiliation(s)
- G J S Cooper
- School of Biological Sciences, and Maurice Wilkins Centre of Excellence for Molecular Biodiscovery, Faculty of Science, University of Auckland, Auckland, New Zealand.
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16
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Aitken JF, Loomes KM, Scott DW, Reddy S, Phillips AR, Prijic G, Fernando C, Zhang S, Broadhurst R, L'Huillier P, Cooper GJ. Tetracycline treatment retards the onset and slows the progression of diabetes in human amylin/islet amyloid polypeptide transgenic mice. Diabetes 2010; 59:161-71. [PMID: 19794060 PMCID: PMC2797917 DOI: 10.2337/db09-0548] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
OBJECTIVE Aggregation of human amylin/islet amyloid polypeptide (hA/hIAPP) into small soluble beta-sheet-containing oligomers is linked to islet beta-cell degeneration and the pathogenesis of type 2 diabetes. Here, we used tetracycline, which modifies hA/hIAPP oligomerization, to probe mechanisms whereby hA/hIAPP causes diabetes in hemizygous hA/hIAPP-transgenic mice. RESEARCH DESIGN AND METHODS We chronically treated hemizygous hA/hIAPP transgenic mice with oral tetracycline to determine its effects on rates of diabetes initiation, progression, and survival. RESULTS Homozygous mice developed severe spontaneous diabetes due to islet beta-cell loss. Hemizygous transgenic animals also developed spontaneous diabetes, although severity was less and progression rates slower. Pathogenesis was characterized by initial islet beta-cell dysfunction followed by progressive beta-cell loss. Islet amyloid was absent from hemizygous animals with early-onset diabetes and correlated positively with longevity. Some long-lived nondiabetic hemizygous animals also had large islet-amyloid areas, showing that amyloid itself was not intrinsically cytotoxic. Administration of tetracycline dose-dependently ameliorated hyperglycemia and polydipsia, delayed rates of diabetes initiation and progression, and increased longevity compared with water-treated controls. CONCLUSIONS This is the first report to show that treating hA/hIAPP transgenic mice with a modifier of hA/hIAPP misfolding can ameliorate their diabetic phenotype. Fibrillar amyloid was neither necessary nor sufficient to cause diabetes and indeed was positively correlated with longevity therein, whereas early- to mid-stage diabetes was associated with islet beta-cell dysfunction followed by beta-cell loss. Interventions capable of suppressing misfolding in soluble hA/hIAPP oligomers rather than mature fibrils may have potential for treating or preventing type 2 diabetes.
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Affiliation(s)
- Jacqueline F. Aitken
- School of Biological Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, Faculty of Science, University of Auckland, Auckland, New Zealand
| | - Kerry M. Loomes
- School of Biological Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, Faculty of Science, University of Auckland, Auckland, New Zealand
| | - David W. Scott
- School of Biological Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
- Department of Medicine, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Shivanand Reddy
- School of Biological Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Anthony R.J. Phillips
- School of Biological Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, Faculty of Science, University of Auckland, Auckland, New Zealand
- Department of Surgery, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Gordana Prijic
- School of Biological Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Chathurini Fernando
- School of Biological Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Shaoping Zhang
- School of Biological Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, Faculty of Science, University of Auckland, Auckland, New Zealand
| | | | | | - Garth J.S. Cooper
- School of Biological Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, Faculty of Science, University of Auckland, Auckland, New Zealand
- Department of Medicine, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
- Department of Pharmacology, Medical Sciences Division, University of Oxford, Oxford, U.K
- Corresponding author: Garth J.S. Cooper,
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Joly E, Roduit R, Peyot ML, Habinowski SA, Ruderman NB, Witters LA, Prentki M. Glucose represses PPARα gene expression via AMP-activated protein kinase but not via p38 mitogen-activated protein kinase in the pancreatic β-cell. J Diabetes 2009; 1:263-72. [PMID: 20923527 DOI: 10.1111/j.1753-0407.2009.00043.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Peroxisome proliferator-activated receptor α (PPARα) regulates the expression of fatty acid metabolism genes and is thought to play a role in the regulation of insulin secretion and lipid detoxification. We have examined the mechanism whereby glucose decreases PPARα gene expression in the pancreatic β-cell. METHODS INS832/13 β-cell and isolated rat islets were incubated at 3 and 20 mM glucose for 18 h in the absence or presence of adenosine monophosphate (AMP)-activated protein kinase (AMPK) activators and inhibitors, as well as p38 mitogen-activated protein kinase (p38 MAPK) inhibitors. In another set of experiments, INS832/13 were infected with an adenovirus expressing a dominant-negative form of AMPK. PPARα expression levels were measured by reverse transcription polymerase chain reaction and Western blot. RESULTS Elevated glucose reduced the abundance of the PPARα transcript and protein, and its target genes acyl-coenzyme A (CoA) oxidase (ACO) and uncoupling protein 2 (UCP-2) in INS832/13 β-cell and isolated rat islets. Glucose reduced AMPK activity, while the AMPK activators 5-amino-4-imidazolecarboxamide riboside and metformin increased PPARα expression and suppressed the action of glucose. By contrast, the AMPK inhibitor compound C mimicked the glucose effect. A dominant negative form of AMPKα reduced the PPARα, ACO and UCP-2 transcripts to the same extent as elevated glucose. Pharmacological evidence indicated that glucose-regulated PPARα expression does not involve p38 MAPK, a target of AMPK in several cell types. CONCLUSIONS The results indicate that glucose represses PPARα gene expression via AMPK, but not via p38 MAPK in the β-cell.
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Affiliation(s)
- Erik Joly
- Montreal Diabetes Research Center and CRCHUM, Montréal, Québec, Canada.
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18
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Li XL, Xu G, Chen T, Wong YS, Zhao HL, Fan RR, Gu XM, Tong PC, Chan JC. Phycocyanin protects INS-1E pancreatic beta cells against human islet amyloid polypeptide-induced apoptosis through attenuating oxidative stress and modulating JNK and p38 mitogen-activated protein kinase pathways. Int J Biochem Cell Biol 2009; 41:1526-35. [PMID: 19166964 DOI: 10.1016/j.biocel.2009.01.002] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2008] [Revised: 12/22/2008] [Accepted: 01/05/2009] [Indexed: 12/20/2022]
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Sphingomyelinase dependent apoptosis following treatment of pancreatic beta-cells with amyloid peptides Aß1-42 or IAPP. Apoptosis 2009; 14:878-89. [DOI: 10.1007/s10495-009-0364-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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20
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Park SY, Cho JH, Oh DY, Park JW, Ahn MJ, Han JS, Oh JW. House dust mite allergen Der f 2-induced phospholipase D1 activation is critical for the production of interleukin-13 through activating transcription factor-2 activation in human bronchial epithelial cells. J Biol Chem 2009; 284:20099-110. [PMID: 19487697 DOI: 10.1074/jbc.m109.010017] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The purpose of this study was to identify the role of phospholipase D1 (PLD1) in Der f 2-induced interleukin (IL)-13 production. The major house dust mite allergen, Der f 2, increased PLD activity in human bronchial epithelial cells (BEAS-2B), and dominant negative PLD1 or PLD1 siRNA decreased Der f 2-induced IL-13 expression and production. Treatment of Der f 2 activated the phospholipase Cgamma (PLCgamma)/protein kinase Calpha (PKCalpha)/p38 MAPK pathway. Der f 2-induced PLD activation was attenuated by PLCgamma inhibitors (U73122 and PAO), PKCalpha inhibitors (RO320432 and GO6976), and p38 MAPK inhibitors (SB203580 and SB202190). These results indicate that PLCgamma, PKCalpha, and p38 MAPK act as upstream activators of PLD in Der f 2-treated BEAS-2B cells. Furthermore, expression and production of IL-13 increased by Der f 2 were also blocked by inhibition of PLCgamma, PKCalpha, or p38 MAPK, indicating that IL-13 expression and production are related to a PLCgamma/PKCalpha/p38 MAPK pathway. We found that activating transcription factor-2 (ATF-2) was activated by Der f 2 in BEAS-2B cells and activation of ATF-2 was controlled by PLD1. When ATF-2 activity was blocked with ATF-2 siRNA, Der f 2-induced IL-13 expression and production were decreased. Thus, ATF-2 might be one of the transcriptional factors for the expression of IL-13 in Der f 2-treated BEAS-2B cells. Taken together, PLD1 acts as an important regulator in Der f 2-induced expression and production of IL-13 through activation of ATF-2 in BEAS-2B cells.
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Affiliation(s)
- Shin-Young Park
- Department of Biochemistry and Molecular Biology, College of Medicine, Hanyang University, Sungdong-Gu, Seoul, Korea
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21
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Chathoth S, Thayyullathil F, Hago A, Shahin A, Patel M, Galadari S. UVC-induced apoptosis in Dubca cells is independent of JNK activation and p53(Ser-15) phosphorylation. Biochem Biophys Res Commun 2009; 383:426-32. [PMID: 19376088 DOI: 10.1016/j.bbrc.2009.04.040] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2009] [Accepted: 04/02/2009] [Indexed: 01/15/2023]
Abstract
Ultraviolet C (UVC) irradiation in mammalian cell lines activates a complex signaling network that leads to apoptosis. By using Dubca cells as a model system, we report the presence of a UVC-induced apoptotic pathway that is independent of c-Jun N-terminal kinases (JNKs) activation and p53 phosphorylation at Ser(15). Irradiation of Dubca cells with UVC results in a rapid JNK activation and phosphorylation of its downstream target c-Jun, as well as, phosphorylation of activating transcription factor 2 (ATF2). Pre-treatment with JNK inhibitor, SP600125, inhibited UVC-induced c-Jun phosphorylation without preventing UVC-induced apoptosis. Similarly, inhibition of UVC-induced p53 phosphorylation did not prevent Dubca cell apoptosis, suggesting that p53(Ser-15) phosphorylation is not associated with UVC-induced apoptosis signaling. The pan-caspase inhibitor z-VAD-fmk inhibited UVC-induced PARP cleavage, DNA fragmentation, and ultimately apoptosis of Dubca cells. Altogether, our study clearly indicates that UVC-induced apoptosis is independent of JNK and p53 activation in Dubca cells, rather, it is mediated through a caspase dependent pathway. Our findings are not in line with the ascribed critical role for JNKs activation, and downstream phosphorylation of targets such as c-Jun and ATF2 in UVC-induced apoptosis.
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Affiliation(s)
- Shahanas Chathoth
- Cell Signaling Laboratory, Department of Biochemistry, Faculty of Medicine and Health Sciences, UAE University, P.O. Box 17666, Al Ain, United Arab Emirates
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Wong WP, Scott DW, Chuang CL, Zhang S, Liu H, Ferreira A, Saafi EL, Choong YS, Cooper GJ. Spontaneous diabetes in hemizygous human amylin transgenic mice that developed neither islet amyloid nor peripheral insulin resistance. Diabetes 2008; 57:2737-44. [PMID: 18633116 PMCID: PMC2551684 DOI: 10.2337/db06-1755] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2006] [Accepted: 06/30/2008] [Indexed: 01/09/2023]
Abstract
OBJECTIVES We sought to 1) Determine whether soluble-misfolded amylin or insoluble-fibrillar amylin may cause or result from diabetes in human amylin transgenic mice and 2) determine the role, if any, that insulin resistance might play in these processes. RESEARCH DESIGN AND METHODS We characterized the phenotypes of independent transgenic mouse lines that display pancreas-specific expression of human amylin or a nonaggregating homolog, [(25,28,29)Pro]human amylin, in an FVB/n background. RESULTS Diabetes occurred in hemizygous human amylin transgenic mice from 6 weeks after birth. Glucose tolerance was impaired during the mid- and end-diabetic phases, in which progressive beta-cell loss paralleled decreasing pancreatic and plasma insulin and amylin. Peripheral insulin resistance was absent because glucose uptake rates were equivalent in isolated soleus muscles from transgenic and control animals. Even in advanced diabetes, islets lacked amyloid deposits. In islets from nontransgenic mice, glucagon and somatostatin cells were present mainly at the periphery and insulin cells were mainly in the core; in contrast, all three cell types were distributed throughout the islet in transgenic animals. [(25,28,29)Pro]human amylin transgenic mice developed neither beta-cell degeneration nor glucose intolerance. CONCLUSIONS Overexpression of fibrillogenic human amylin in these human amylin transgenic mice caused beta-cell degeneration and diabetes through mechanisms independent from both peripheral insulin resistance and islet amyloid. These findings are consistent with beta-cell death evoked by misfolded but soluble cytotoxic species, such as those formed by human amylin in vitro.
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Affiliation(s)
- Winifred P.S. Wong
- School of Biological Sciences, Faculty of Science, University of Auckland, Auckland, New Zealand
| | - David W. Scott
- School of Biological Sciences, Faculty of Science, University of Auckland, Auckland, New Zealand
| | - Chia-Lin Chuang
- School of Biological Sciences, Faculty of Science, University of Auckland, Auckland, New Zealand
| | - Shaoping Zhang
- School of Biological Sciences, Faculty of Science, University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| | - Hong Liu
- School of Biological Sciences, Faculty of Science, University of Auckland, Auckland, New Zealand
| | - Athena Ferreira
- School of Biological Sciences, Faculty of Science, University of Auckland, Auckland, New Zealand
| | - Etuate L. Saafi
- School of Biological Sciences, Faculty of Science, University of Auckland, Auckland, New Zealand
| | - Yee Soon Choong
- School of Biological Sciences, Faculty of Science, University of Auckland, Auckland, New Zealand
| | - Garth J.S. Cooper
- School of Biological Sciences, Faculty of Science, University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
- MRC Immunochemistry Unit, Department of Biochemistry, University of Oxford, Oxford, U.K
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Integrative decomposition procedure and Kappa statistics set up ATF2 ion binding module in malignant pleural mesothelioma (MPM). ACTA ACUST UNITED AC 2008. [DOI: 10.1007/s11460-008-0086-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Haataja L, Gurlo T, Huang CJ, Butler PC. Islet amyloid in type 2 diabetes, and the toxic oligomer hypothesis. Endocr Rev 2008; 29:303-16. [PMID: 18314421 PMCID: PMC2528855 DOI: 10.1210/er.2007-0037] [Citation(s) in RCA: 469] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Type 2 diabetes (T2DM) is characterized by insulin resistance, defective insulin secretion, loss of beta-cell mass with increased beta-cell apoptosis and islet amyloid. The islet amyloid is derived from islet amyloid polypeptide (IAPP, amylin), a protein coexpressed and cosecreted with insulin by pancreatic beta-cells. In common with other amyloidogenic proteins, IAPP has the propensity to form membrane permeant toxic oligomers. Accumulating evidence suggests that these toxic oligomers, rather than the extracellular amyloid form of these proteins, are responsible for loss of neurons in neurodegenerative diseases. In this review we discuss emerging evidence to suggest that formation of intracellular IAPP oligomers may contribute to beta-cell loss in T2DM. The accumulated evidence permits the amyloid hypothesis originally developed for neurodegenerative diseases to be reformulated as the toxic oligomer hypothesis. However, as in neurodegenerative diseases, it remains unclear exactly why amyloidogenic proteins form oligomers in vivo, what their exact structure is, and to what extent these oligomers play a primary or secondary role in the cytotoxicity in what are now often called unfolded protein diseases.
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Affiliation(s)
- Leena Haataja
- Larry Hillblom Islet Research Center, UCLA David Geffen School of Medicine, 900 Weyburn Place #A, Los Angeles, California 90024-2852, USA
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25
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Fukuda K, Tesch GH, Yap FY, Forbes JM, Flavell RA, Davis RJ, Nikolic-Paterson DJ. MKK3 signalling plays an essential role in leukocyte-mediated pancreatic injury in the multiple low-dose streptozotocin model. J Transl Med 2008; 88:398-407. [PMID: 18283273 DOI: 10.1038/labinvest.2008.10] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
In vitro studies have implicated activation of the p38 mitogen-activated protein kinase (MAPK) signalling pathway in cytokine-mediated pancreatic beta-cell injury. Activation of the p38 MAPK occurs through two different upstream kinases, mitogen-activated protein kinase kinase 3 (MKK3) and MKK6. This study examined the role of MKK3 signalling in an in vivo model of cytokine-dependent pancreatic injury induced by multiple low doses of streptozotocin (MLD-STZ). Groups of wild-type (WT) or Mkk3-/- C57BL/6J mice received 5 daily injections of STZ (40 mg/kg) and were killed on day 5, week 2 or week 4. MLD-STZ in WT mice exhibited two distinct phases of pancreatic damage: islet cell apoptosis (immunostaining for cleaved caspase-3) on day 5 in the absence of leukocyte infiltration, and this was followed by islet inflammation (leukocyte infiltration and cytokine production) and further islet cell apoptosis on day 14 resulting in a loss of insulin-producing beta-cells and an 80% incidence of hyperglycaemia. Mkk3-/- mice were not protected from the initial phase of STZ-induced islet cell apoptosis day 5. However, Mkk3-/- mice were completely protected from the induction of hyperglycaemia. This was attributed to inhibition of leukocyte infiltration, production of pro-inflammatory cytokines and islet cell apoptosis at day 14 of MLD-STZ. In vitro studies showed that cultured islets from Mkk3-/- and WT mice are equally susceptible to STZ and cytokine-induced apoptosis. In conclusion, MKK3 signalling plays an essential role in the development of islet inflammation leading to destruction of beta-cells and hyperglycaemia in MLD-STZ-induced pancreatic injury.
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Affiliation(s)
- Kyoichi Fukuda
- Department of Nephrology, Monash Medical Centre, Clayton, Vic, Australia
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Zhang S, Liu H, Yu H, Cooper GJS. Fas-associated death receptor signaling evoked by human amylin in islet beta-cells. Diabetes 2008; 57:348-56. [PMID: 17977957 DOI: 10.2337/db07-0849] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Aggregation of human amylin (hA) into beta-sheet-containing oligomers is linked to islet beta-cell dysfunction and the pathogenesis of type 2 diabetes. Here, we investigated possible contributions of Fas-associated death-receptor signaling to the mechanism of hA-evoked beta-cell apoptosis. RESEARCH DESIGN AND METHODS We measured responses to hA in isolated mouse islets and two insulinoma cell lines, wherein we measured Fas/Fas ligand (FasL) and Fas-associated death domain (FADD) expression by quantitative RT-PCR, Western blotting, and immunofluorescence staining. We used two anti-Fas/FasL blocking antibodies and the Fas/FasL antagonist Kp7-6 to probe roles of Fas interactions in the regulation of apoptosis in hA-treated beta-cells and measured Kp7-6-mediated effects on beta-sheet formation and aggregation using circular dichroism and thioflavin-T binding. RESULTS hA treatment stimulated Fas and FADD expression in beta-cells. Both blocking antibodies suppressed hA-evoked apoptosis but did not modify its aggregation. Therefore, Fas receptor interactions played a critical role in induction of this pathway. Interestingly, hA-evoked beta-cell apoptosis was suppressed and rescued by Kp7-6, which also impaired hA beta-sheet formation. CONCLUSIONS This is the first report linking hA-evoked induction and activation of Fas and FADD to beta-cell apoptosis. We have identified a Fas/FasL antagonist, Kp7-6, as a potent inhibitor of hA aggregation and related beta-cell death. These results also support an interaction between hA and Fas on the surface of apoptotic beta-cells. Increased expression and activation of Fas in beta-cells could constitute a molecular event common to the pathogenesis of both type 1 and type 2 diabetes, although the mode of pathway activation may differ between these common forms of diabetes.
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Affiliation(s)
- Shaoping Zhang
- School of Biological Sciences, University of Auckland, Level 4, 3A Symonds St., Private Bag 92019, Auckland 1142, New Zealand
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Hay CW, Ferguson LA, Docherty K. ATF-2 stimulates the human insulin promoter through the conserved CRE2 sequence. ACTA ACUST UNITED AC 2007; 1769:79-91. [PMID: 17337306 DOI: 10.1016/j.bbaexp.2007.01.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2006] [Revised: 01/22/2007] [Accepted: 01/22/2007] [Indexed: 01/04/2023]
Abstract
The insulin promoter contains a number of dissimilar cis-acting regulatory elements that bind a range of tissue specific and ubiquitous transcription factors. Of the regulatory elements within the insulin promoter, the cyclic AMP responsive element (CRE) binds by far the most diverse array of transcription factors. Rodent insulin promoters have a single CRE site, whereas there are four CREs within the human insulin gene, of which CRE2 is the only one conserved between species. The aim of this study was to characterise the human CRE2 site and to investigate the effects of the two principal CRE-associated transcription factors; CREB-1 and ATF-2. Co-transfection of INS-1 pancreatic beta-cells with promoter constructs containing the human insulin gene promoter placed upstream of the firefly luciferase reporter gene and expression plasmids for ATF-2 or CREB-1 showed that ATF-2 stimulated transcriptional activity while CREB-1 elicited an inhibitory effect. Mutagenesis of CRE2 diminished the effect of ATF-2 but not that of CREB-1. ATF-2 was shown to bind to the CRE2 site by electrophoretic mobility shift assay and by chromatin immunoprecipitation, while siRNA mediated knockdown of ATF-2 diminished the stimulatory effects of cAMP related signalling on promoter activity. These results suggest that ATF-2 may be a key regulator of the human insulin promoter possibly stimulating activity in response to extracellular signals.
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Affiliation(s)
- Colin W Hay
- School of Medical Sciences, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen, AB25 2ZD, UK
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