101
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Kamimura J, Wakui K, Kadowaki H, Watanabe Y, Miyake K, Harada N, Sakamoto M, Kinoshita A, Yoshiura KI, Ohta T, Kishino T, Ishikawa M, Kasuga M, Fukushima Y, Niikawa N, Matsumoto N. The IHPK1 gene is disrupted at the 3p21.31 breakpoint of t(3;9) in a family with type 2 diabetes mellitus. J Hum Genet 2004; 49:360-365. [PMID: 15221640 DOI: 10.1007/s10038-004-0158-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2004] [Accepted: 03/31/2004] [Indexed: 11/30/2022]
Abstract
Type 2 diabetes mellitus (T2DM) is a group of multifactorial disorders due to either defective insulin secretion or action. Despite the fact that numerous genetic researches of T2DM have been pursued, the pathogenic mechanisms remain obscure. We encountered a T2DM family associated with a balanced reciprocal translocation, t(3;9)(p21.31;q33.1). To isolate a candidate gene susceptible to T2DM, we constructed physical maps covering both the 3p and 9q breakpoints of the translocation in the family. Consequently, the inositol hexaphosphate kinase 1 gene ( IHPK1) (OMIM *606991) was found to be disrupted at the 3p21.31 breakpoint. We then carried out sequence analysis for all coding regions of IHPK1 in 405 unrelated T2DM patients in order to validate whether aberrations of the gene are common in T2DM patients, but we failed to detect any pathogenic changes. The disruption of IHPK1 or another predisposing gene affected by position effect of the translocation may explain the T2DM phenotype at least in this family. Alternatively, the IHPK1 disruption in the family is a chance association.
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MESH Headings
- Adolescent
- Chromosomes, Artificial, Bacterial
- Chromosomes, Human, Pair 3
- Chromosomes, Human, Pair 9
- Cloning, Molecular
- Cosmids/metabolism
- DNA Mutational Analysis
- Diabetes Mellitus, Type 2/genetics
- Exons
- Family Health
- Female
- Humans
- In Situ Hybridization, Fluorescence
- Male
- Models, Genetic
- Mutation
- Phosphotransferases (Phosphate Group Acceptor)/genetics
- Sequence Analysis, DNA
- Software
- Translocation, Genetic
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Affiliation(s)
- Junichi Kamimura
- Department of Human Genetics, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
- Department of Obstetrics and Gynecology, Asahikawa Medical College, Asahikawa, Japan
- CREST, Japan Science and Technology Agency, Kawaguchi, Japan
| | - Keiko Wakui
- Department of Medical Genetics, Shinshu University School of Medicine, Matsumoto, Japan
| | - Hiroko Kadowaki
- Department of Clinical Bioinformatics, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
| | - Yukio Watanabe
- Department of Human Genetics, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
- Department of Obstetrics and Gynecology, Asahikawa Medical College, Asahikawa, Japan
| | - Kazuaki Miyake
- Division of Diabetes, Digestive and Kidney Disease, Department of Clinical Molecular Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Naoki Harada
- Department of Human Genetics, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
- CREST, Japan Science and Technology Agency, Kawaguchi, Japan
- Kyushu Medical Science Nagasaki Laboratory, Nagasaki, Japan
| | - Michiyo Sakamoto
- Division of Pediatrics, Yamagata City Hospital Saiseikan, Yamagata, Japan
| | - Akira Kinoshita
- Department of Human Genetics, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
- CREST, Japan Science and Technology Agency, Kawaguchi, Japan
| | - Koh-Ichiro Yoshiura
- Department of Human Genetics, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
- CREST, Japan Science and Technology Agency, Kawaguchi, Japan
| | - Tohru Ohta
- CREST, Japan Science and Technology Agency, Kawaguchi, Japan
- Division of Functional Genomics, Research Center for Frontier Life Sciences, Nagasaki University, Nagasaki, Japan
| | - Tatsuya Kishino
- CREST, Japan Science and Technology Agency, Kawaguchi, Japan
- Division of Functional Genomics, Research Center for Frontier Life Sciences, Nagasaki University, Nagasaki, Japan
| | - Mutsuo Ishikawa
- Department of Obstetrics and Gynecology, Asahikawa Medical College, Asahikawa, Japan
| | - Masato Kasuga
- Division of Diabetes, Digestive and Kidney Disease, Department of Clinical Molecular Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yoshimitsu Fukushima
- CREST, Japan Science and Technology Agency, Kawaguchi, Japan
- Department of Medical Genetics, Shinshu University School of Medicine, Matsumoto, Japan
| | - Norio Niikawa
- Department of Human Genetics, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
- CREST, Japan Science and Technology Agency, Kawaguchi, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
- CREST, Japan Science and Technology Agency, Kawaguchi, Japan.
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan.
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102
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Brunelli S, Tagliafico E, De Angelis FG, Tonlorenzi R, Baesso S, Ferrari S, Niinobe M, Yoshikawa K, Schwartz RJ, Bozzoni I, Ferrari S, Cossu G. Msx2 and necdin combined activities are required for smooth muscle differentiation in mesoangioblast stem cells. Circ Res 2004; 94:1571-8. [PMID: 15155529 DOI: 10.1161/01.res.0000132747.12860.10] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Little is known about the molecular mechanism underlying specification and differentiation of smooth muscle (SM), and this is, at least in part, because of the few cellular systems available to study the acquisition of a SM phenotype in vitro. Mesoangioblasts are vessel-derived stem cells that can be induced to differentiate into different cell types of the mesoderm, including SM. We performed a DNA microarray analysis of a mesoangioblast clone that spontaneously expresses an immature SM phenotype and compared it with a sister clone mainly composed of undifferentiated progenitor cells. This study allowed us to define a gene expression profile for "stem" cells versus smooth muscle cells (SMCs) in the absence of differentiation inducers such as transforming growth factor beta. Two transcription factors, msx2 and necdin, are expressed at least 100 times more in SMCs than in stem cells, are coexpressed in all SMCs and tissues, are induced by transforming growth factor beta, and, when coexpressed, induce a number of SM markers in mesoangioblast, fibroblast, and endothelial cell lines. Conversely, their downregulation through RNA interference results in a decreased expression of SM markers. These data support the hypothesis that Msx2 and necdin act as master genes regulating SM differentiation in at least a subset of SMCs.
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103
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Heo YS, Kim SK, Seo CI, Kim YK, Sung BJ, Lee HS, Lee JI, Park SY, Kim JH, Hwang KY, Hyun YL, Jeon YH, Ro S, Cho JM, Lee TG, Yang CH. Structural basis for the selective inhibition of JNK1 by the scaffolding protein JIP1 and SP600125. EMBO J 2004; 23:2185-95. [PMID: 15141161 PMCID: PMC419904 DOI: 10.1038/sj.emboj.7600212] [Citation(s) in RCA: 221] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2003] [Accepted: 03/22/2004] [Indexed: 11/08/2022] Open
Abstract
The c-jun N-terminal kinase (JNK) signaling pathway is regulated by JNK-interacting protein-1 (JIP1), which is a scaffolding protein assembling the components of the JNK cascade. Overexpression of JIP1 deactivates the JNK pathway selectively by cytoplasmic retention of JNK and thereby inhibits gene expression mediated by JNK, which occurs in the nucleus. Here, we report the crystal structure of human JNK1 complexed with pepJIP1, the peptide fragment of JIP1, revealing its selectivity for JNK1 over other MAPKs and the allosteric inhibition mechanism. The van der Waals contacts by the three residues (Pro157, Leu160, and Leu162) of pepJIP1 and the hydrogen bonding between Glu329 of JNK1 and Arg156 of pepJIP1 are critical for the selective binding. Binding of the peptide also induces a hinge motion between the N- and C-terminal domains of JNK1 and distorts the ATP-binding cleft, reducing the affinity of the kinase for ATP. In addition, we also determined the ternary complex structure of pepJIP1-bound JNK1 complexed with SP600125, an ATP-competitive inhibitor of JNK, providing the basis for the JNK specificity of the compound.
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Affiliation(s)
- Yong-Seok Heo
- The Division of Drug Discovery, CrystalGenomics, Inc., Daeduk Biocommunity, Jeonmin-dong, Yuseong-gu, Daejon, Korea
- Molecular Enzymology Laboratory, School of Chemistry and Molecular Engineering, Seoul National University, Seoul, Korea
| | - Su-Kyoung Kim
- The Division of Drug Discovery, CrystalGenomics, Inc., Daeduk Biocommunity, Jeonmin-dong, Yuseong-gu, Daejon, Korea
| | - Chang Il Seo
- The Division of Drug Discovery, CrystalGenomics, Inc., Daeduk Biocommunity, Jeonmin-dong, Yuseong-gu, Daejon, Korea
| | - Young Kwan Kim
- The Division of Drug Discovery, CrystalGenomics, Inc., Daeduk Biocommunity, Jeonmin-dong, Yuseong-gu, Daejon, Korea
| | - Byung-Je Sung
- The Division of Drug Discovery, CrystalGenomics, Inc., Daeduk Biocommunity, Jeonmin-dong, Yuseong-gu, Daejon, Korea
| | - Hye Shin Lee
- The Division of Drug Discovery, CrystalGenomics, Inc., Daeduk Biocommunity, Jeonmin-dong, Yuseong-gu, Daejon, Korea
| | - Jae Il Lee
- The Division of Drug Discovery, CrystalGenomics, Inc., Daeduk Biocommunity, Jeonmin-dong, Yuseong-gu, Daejon, Korea
| | - Sam-Yong Park
- Protein Design Laboratory, Yokohama City University, Suechiro-cho, Tsurumi, Yokohama, Japan
| | - Jin Hwan Kim
- The Division of Drug Discovery, CrystalGenomics, Inc., Daeduk Biocommunity, Jeonmin-dong, Yuseong-gu, Daejon, Korea
| | - Kwang Yeon Hwang
- The Division of Drug Discovery, CrystalGenomics, Inc., Daeduk Biocommunity, Jeonmin-dong, Yuseong-gu, Daejon, Korea
| | - Young-Lan Hyun
- The Division of Drug Discovery, CrystalGenomics, Inc., Daeduk Biocommunity, Jeonmin-dong, Yuseong-gu, Daejon, Korea
| | - Young Ho Jeon
- The Division of Drug Discovery, CrystalGenomics, Inc., Daeduk Biocommunity, Jeonmin-dong, Yuseong-gu, Daejon, Korea
| | - Seonggu Ro
- The Division of Drug Discovery, CrystalGenomics, Inc., Daeduk Biocommunity, Jeonmin-dong, Yuseong-gu, Daejon, Korea
| | - Joong Myung Cho
- The Division of Drug Discovery, CrystalGenomics, Inc., Daeduk Biocommunity, Jeonmin-dong, Yuseong-gu, Daejon, Korea
| | - Tae Gyu Lee
- The Division of Drug Discovery, CrystalGenomics, Inc., Daeduk Biocommunity, Jeonmin-dong, Yuseong-gu, Daejon, Korea
- CrystalGenomics, Inc., Daeduk Biocommunity, Jeonmin-dong, Yuseong-gu, Daejeon 305-390, Korea. Tel.: +82 42 866 9320; Fax: +82 42 866 9301; E-mail:
| | - Chul-Hak Yang
- Molecular Enzymology Laboratory, School of Chemistry and Molecular Engineering, Seoul National University, Seoul, Korea
- Molecular Enzymology Laboratory, School of Chemistry and Molecular Engineering, Seoul National University, NS60, Seoul 151-742, Korea. Tel.: +82 2 878 8545; Fax: +82 2 889 1568; E-mail:
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104
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Abderrahmani A, Niederhauser G, Plaisance V, Roehrich ME, Lenain V, Coppola T, Regazzi R, Waeber G. Complexin I regulates glucose-induced secretion in pancreatic β-cells. J Cell Sci 2004; 117:2239-47. [PMID: 15126625 DOI: 10.1242/jcs.01041] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The neuronal-specific protein complexin I (CPX I) plays an important role in controlling the Ca2+-dependent neurotransmitter release. Since insulin exocytosis and neurotransmitter release rely on similar molecular mechanisms and that pancreatic β-cells and neuronal cells share the expression of many restricted genes, we investigated the potential role of CPX I in insulin-secreting cells. We found that pancreatic islets and several insulin-secreting cell lines express high levels of CPX I. The β-cell expression of CPX I is mediated by the presence of a neuron restrictive silencer element located within the regulatory region of the gene. This element bound the transcriptional repressor REST, which is found in most cell types with the exception of mature neuronal cells and β-cells. Overexpression of CPX I or silencing of the CPX I gene (Cplx1) by RNA interference led to strong impairment in β-cell secretion in response to nutrients such as glucose, leucine and KCl. This effect was detected both in the early and the sustained secretory phases but was much more pronounced in the early phase. We conclude that CPX I plays a critical role in β-cells in the control of the stimulated-exocytosis of insulin.
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Affiliation(s)
- Amar Abderrahmani
- Department of Internal Medicine, University of Lausanne, Lausanne, Switzerland
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105
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Abderrahmani A, Niederhauser G, Plaisance V, Haefliger JA, Regazzi R, Waeber G. Neuronal traits are required for glucose-induced insulin secretion. FEBS Lett 2004; 565:133-8. [PMID: 15135066 DOI: 10.1016/j.febslet.2004.04.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2004] [Revised: 04/01/2004] [Accepted: 04/01/2004] [Indexed: 10/26/2022]
Abstract
The transcriptional repressor RE1 silencer transcription factor (REST) is an important factor that restricts some neuronal traits to neurons. Since these traits are also present in pancreatic beta-cells, we evaluated their role by generating a model of insulin-secreting cells that express REST. The presence of REST led to a decrease in expression of its known target genes, whereas insulin expression and its cellular content were conserved. As a consequence of REST expression, the capacity to secrete insulin in response to mitochondrial fuels, a particularity of mature beta-cells, was impaired. These data provide evidence that REST target genes are required for an appropriate glucose-induced insulin secretion.
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Affiliation(s)
- Amar Abderrahmani
- Department of Internal Medicine, University of Lausanne, CHUV-1011 Lausanne, Switzerland
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106
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Abstract
PURPOSE OF REVIEW Numerous epidemiological and clinical data suggest that neurodegenerative disorders, such as Alzheimer's disease, may be related directly or indirectly to cardiovascular risk. Genetic studies have demonstrated that they share at least one common susceptibility gene, encoding apolipoprotein E, a modulator of cardiac risk and of cognitive impairment. Several studies have suggested that other genes involved in the development of cardiovascular diseases may be involved. Previous studies indicated that additional genes contribute to Alzheimer's disease, in particular to the sporadic, more common late-onset form. In this review, the authors focus on recent findings concerning the modulation of the risk of Alzheimer's disease by genes also involved in the development of cardiovascular diseases. RECENT FINDINGS The intensive search conducted in the past year gave rise to many publications, more than half of which were related to genes common to cardiovascular and neurodegenerative disorders. The majority of the genes studied are involved in cholesterol metabolism, hypertension, lipid oxidation and detoxication, or inflammatory processes. SUMMARY In the past year, approximately 100 studies concerning the genetics of Alzheimer's disease were published around the world. Results suggest that the risk of Alzheimer's disease is modulated by various genes encoding proteins involved in cholesterol metabolism, in the detoxication of lipoprotein oxidation or encoding cytokines.
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Affiliation(s)
- Nicole Helbecque
- Service d'Epidémiologie et de Santé Publique, INSERM U508, Institut Pasteur de Lille, France
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107
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Abstract
The c-Jun N-terminal kinase (JNK) signaling pathway is a major mediator of stress responses in cells. Similar to other mitogen-activated protein kinases (MAPKs), JNK activity is controlled by a cascade of protein kinases and by protein phosphatases, including dual-specificity MAPK phosphatases. Components of the JNK pathway associate with scaffold proteins that modulate their activities and cellular localization. The JNK-interacting protein-1 (JIP-1) scaffold protein specifically binds JNK, MAPK kinase 7 (MKK7), and members of the mixed lineage kinase (MLK) family, and regulates JNK activation in neurons. In this study we demonstrate that distinct regions within the N termini of MKK7 and the MLK family member dual leucine zipper kinase (DLK) mediate their binding to JIP-1. We have also identified amino acids in JNK required for: (a) binding to JIP-1 and for JIP-1-mediated JNK activation, (b) docking to MAPK kinase 4 (MKK4) and efficient phosphorylation by MKK4, and (c) docking to its substrate c-Jun and efficient c-Jun phosphorylation. None of the amino acids identified were essential for JNK docking to MKK7 or the dual-specificity phosphatase MAPK phosphatase 7 (MKP7). These findings uncover molecular determinants of JIP-1 scaffold complex assembly and demonstrate that there are overlapping, but also distinct, binding determinants within JNK that mediate interactions with scaffold proteins, activators, phosphatases, and substrates.
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Affiliation(s)
- Lorraine M Mooney
- School of Biological Sciences, University of Manchester, 2.205 Stopford Building, Oxford Road, Manchester M13 9PT, United Kingdom
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108
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Wuyts W, Waeber G, Meinecke P, Schüler H, Goecke TO, Van Hul W, Bartsch O. Proximal 11p deletion syndrome (P11pDS): additional evaluation of the clinical and molecular aspects. Eur J Hum Genet 2004; 12:400-6. [PMID: 14872200 DOI: 10.1038/sj.ejhg.5201163] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The combination of multiple exostoses (EXT) and enlarged parietal foramina (foramina parietalia permagna, FPP) represent the main features of the proximal 11p deletion syndrome (P11pDS), a contiguous gene syndrome (MIM 601224) caused by an interstitial deletion on the short arm of chromosome 11. Here we present clinical aspects of two new P11pDS patients and the clinical follow-up of one patient reported in the original paper describing this syndrome. Recognised clinical signs include EXT, FPP, mental retardation, facial asymmetry, asymmetric calcification of coronary sutures, defective vision (severe myopia, nystagmus, strabismus), skeletal anomalies (small hands and feet, tapering fingers), heart defect, and anal stenosis. In addition fluorescence in situ hybridisation and molecular analysis were performed to gain further insight in potential candidate genes involved in P11pDS.
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Affiliation(s)
- Wim Wuyts
- Department of Medical Genetics, University of Antwerp, Belgium.
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109
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Martin D, Tawadros T, Meylan L, Abderrahmani A, Condorelli DF, Waeber G, Haefliger JA. Critical role of the transcriptional repressor neuron-restrictive silencer factor in the specific control of connexin36 in insulin-producing cell lines. J Biol Chem 2003; 278:53082-9. [PMID: 14565956 DOI: 10.1074/jbc.m306861200] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Connexin36 (Cx36) is specifically expressed in neurons and in pancreatic beta-cells. Cx36 functions as a critical regulator of insulin secretion and content in beta-cells. In order to identify the molecular mechanisms that control the beta-cell expression of Cx36, we initiated the characterization of the human 5' regulatory region of the CX36 gene. A 2043-bp fragment of the human CX36 promoter was identified from a human BAC library and fused to a luciferase reporter gene. This promoter region was sufficient to confer specific expression to the reporter gene in insulin-secreting cell lines. Within this 5' regulatory region, a putative neuron-restrictive silencer element conserved between rodent and human species was recognized and binds the neuron-restrictive silencing factor (NRSF/REST). This factor is not expressed in insulin-secreting cells and neurons; it functions as a potent repressor through the recruitment of histone deacetylase to the promoter of neuronal genes. The NRSF-mediated repression of Cx36 in HeLa cells was abolished by trichostatin A, confirming the functional importance of histone deacetylase activity. Ectopic expression, by viral gene transfer, of NRSF/REST in different insulin-secreting beta-cell lines induced a marked reduction in Cx36 mRNA and protein content. Moreover, mutations in the Cx36 neuron-restrictive silencer element relieved the low transcriptional activity of the human CX36 promoter observed in HeLa cells and in INS-1 cells expressing NRSF/REST. The data showed that cx36 gene expression in insulin-producing beta-cell lines is strictly controlled by the transcriptional repressor NRSF/REST indicating that Cx36 participates to the neuronal phenotype of the pancreatic beta-cells.
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Affiliation(s)
- David Martin
- Department of Internal Medicine, University Hospital, CHUV-1011 Lausanne, Switzerland
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110
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Kawamori D, Kajimoto Y, Kaneto H, Umayahara Y, Fujitani Y, Miyatsuka T, Watada H, Leibiger IB, Yamasaki Y, Hori M. Oxidative stress induces nucleo-cytoplasmic translocation of pancreatic transcription factor PDX-1 through activation of c-Jun NH(2)-terminal kinase. Diabetes 2003; 52:2896-904. [PMID: 14633849 DOI: 10.2337/diabetes.52.12.2896] [Citation(s) in RCA: 166] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Oxidative stress is induced in pancreatic beta-cells under diabetic conditions and causes beta-cell dysfunction. Antioxidant treatment of diabetic animals leads to recovery of insulin biosynthesis and increases the expression of its controlling transcription factor, pancreatic duodenal homeobox-1 (PDX-1), in pancreatic beta-cells. Here, we show that PDX-1 is translocated from the nuclei to the cytoplasm of pancreatic beta-cells in response to oxidative stress. When oxidative stress was charged upon beta-cell-derived HIT-T15 cells, both endogenous PDX-1 and exogenously introduced green fluorescent protein-tagged PDX-1 moved from the nuclei to the cytoplasm. The addition of a dominant negative form of c-Jun NH(2)-terminal kinase (JNK) inhibited oxidative stress-induced PDX-1 translocation, suggesting an essential role of JNK in mediating this phenomenon. Whereas the nuclear localization signal (NLS) in PDX-1 was not affected by oxidative stress, leptomycin B, a specific inhibitor of the classical leucine-rich nuclear export signal (NES), inhibited nucleo-cytoplasmic translocation of PDX-1 induced by oxidative stress. Moreover, we identified an NES at position 82-94 of the mouse PDX-1 protein. Thus, our present results revealed a novel mechanism that negatively regulates PDX-1 function. The identification of the NES, which overrides the function of the NLS in an oxidative stress-responsive, JNK-dependent manner, supports the complicated regulation of PDX-1 function in vivo and may further the understanding of beta-cell pathophysiology in diabetes.
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Affiliation(s)
- Dan Kawamori
- Department of Internal Medicine and Therapeutics, Osaka University Graduate School of Medicine, Suita City, Osaka, Japan
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111
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Im JY, Lee KW, Kim MH, Lee SH, Ha HY, Cho IH, Kim D, Yu MS, Kim JB, Lee JK, Kim YJ, Youn BW, Yang SD, Shin HS, Han PL. Repression of phospho-JNK and infarct volume in ischemic brain of JIP1-deficient mice. J Neurosci Res 2003; 74:326-32. [PMID: 14515362 DOI: 10.1002/jnr.10761] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Mice lacking JIP1, a scaffold protein that organizes JNK pathway components, were constructed independently by two groups. The proposed in vivo function, however, remains contradictory; One study reported that targeted disruption of the jip1 caused embryonic death due to the requirement of JIP1 for fertilized eggs (Thompson et al. [2001] J. Biol. Chem. 276:27745-27748). In contrast, another group (Whitmarsh et al. [2001] Genes Dev. 15:2421-2432) demonstrated that JIP1-deficient mice were viable and that the JIP1 null mutation inhibited the kainic acid-induced JNK activation and neuronal death. The current study was undertaken to re-elucidate the in vivo roles of JIP1 using newly generated JIP1 knockout mice. Our JIP1-deficient mice were viable and healthy. The transient focal ischemic insult produced by middle cerebral artery occlusion (MCAO) strongly activated JNK in brain of jip1(+/+), jip1(+/-), and jip1(-/-) mice. Increased JNK activity was sustained for more than 22 hr in jip1(+/+) and jip1(+/-), whereas it was repressed rapidly in jip1(-/-). Concomitantly, the infarct volume produced by the ischemic insult in jip1(-/-) was reduced notably compared to that in jip1(+/+) brain. These results suggest that JIP1 plays a pivotal role in regulating the maintenance of phosphorylated JNK and neuronal survival in postischemic brain, but is not essential for JNK activation and early development.
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Affiliation(s)
- Joo-Young Im
- Department of Neuroscience, Ewha Institute of Neuroscience and Medical Research Center, Ewha Womans University School of Medicine, Seoul, Korea
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112
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Ling Z, Van de Casteele M, Dong J, Heimberg H, Haefliger JA, Waeber G, Schuit F, Pipeleers D. Variations in IB1/JIP1 expression regulate susceptibility of beta-cells to cytokine-induced apoptosis irrespective of C-Jun NH2-terminal kinase signaling. Diabetes 2003; 52:2497-502. [PMID: 14514632 DOI: 10.2337/diabetes.52.10.2497] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We previously reported that interleukin-1beta (IL-1beta) alone does not cause apoptosis of beta-cells, whereas when combined with gamma-interferon (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha), it exerts a distinct apoptotic effect. Studies in beta-cell lines indicated that IL-1beta reduced expression of islet brain (IB)-1/JNK interacting protein (JIP)-1, a JNK scaffold protein with antiapoptotic action. We examined whether variations in IB1/JIP-1 expression in purified primary beta-cells affect their susceptibility to cytokine-induced apoptosis. Exposure to IL-1beta for 24 h decreased cellular IB1/JIP-1 content by 66 +/- 17%; this IL-1beta effect was maintained in the presence of TNF-alpha + IFN-gamma, which did not influence IB1/JIP-1 levels by themselves. Addition of IL-1beta to TNF-alpha + IFN-gamma increased apoptosis from 20 +/- 2% to 59 +/- 5%. A similar increase in TNF-alpha + IFN-gamma-induced apoptosis was produced by adenoviral expression of antisense IB1/JIP-1 and was not further enhanced by addition of IL-1beta, indicating that IL-1beta-mediated suppression of IB1/JIP-1 in beta-cells increases their susceptibility to cytokine-induced apoptosis. However, adenovirally mediated overexpression of IB1/JIP-1 also potentiated TNF-alpha + IFN-gamma-induced apoptosis, suggesting that the antiapoptotic effect of IB1/JIP-1 depends on well-defined cellular levels. We conclude that the IB1/JIP-1 level in beta-cells can control their susceptibility to apoptosis independent of JNK signaling.
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Affiliation(s)
- Zhidong Ling
- Diabetes Research Center, Brussels Free University-VUB, Brussels, Belgium.
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113
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Allaman-Pillet N, Størling J, Oberson A, Roduit R, Negri S, Sauser C, Nicod P, Beckmann JS, Schorderet DF, Mandrup-Poulsen T, Bonny C. Calcium- and proteasome-dependent degradation of the JNK scaffold protein islet-brain 1. J Biol Chem 2003; 278:48720-6. [PMID: 14507925 DOI: 10.1074/jbc.m306745200] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
In models of type 1 diabetes, cytokines induce pancreatic beta-cell death by apoptosis. This process seems to be facilitated by a reduction in the amount of the islet-brain 1/JNK interacting protein 1 (IB1/JIP1), a JNK-scaffold with an anti-apoptotic effect. A point mutation S59N at the N terminus of the scaffold, which segregates in diabetic patients, has the functional consequence of sensitizing cells to apoptotic stimuli. Neither the mechanisms leading to IB1/JIP1 down-regulation by cytokines nor the mechanisms leading to the decreased capacity of the S59N mutation to protect cells from apoptosis are understood. Here, we show that IB1/JIP1 stability is modulated by intracellular calcium. The effect of calcium depends upon JNK activation, which primes the scaffold for ubiquitination-mediated degradation via the proteasome machinery. Furthermore, we observe that the S59N mutation decreases IB1/JIP1 stability by sensitizing IB1/JIP1 to calcium- and proteasome-dependent degradation. These data indicate that calcium influx initiated by cytokines mediates ubiquitination and degradation of IB1/JIP1 and may, therefore, provide a link between calcium influx and JNK-mediated apoptosis in pancreatic beta-cells.
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Affiliation(s)
- Nathalie Allaman-Pillet
- Department of Internal Medicine, Centre Hospitalier Universitaire Vaudois, CH-1011 Lausanne, Switzerland.
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114
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Abstract
Members of the JNK pathway are organized together by virtue of interactions with JNK interacting protein 1 (JIP1), a scaffold protein. Here we have investigated the possibility that JIP1 may also affect the catalytic activity of Akt1, a serine/threonine kinase that has been implicated in multiple cellular processes, including survival and proliferation. JIP1 expression enhanced Akt1 kinase activity in a dose-dependent manner following serum starvation in 293 cells. Cellular activation of Akt1 following stimulation with low concentrations of insulin-like growth factor (IGF-1) was elevated in the presence of JIP1. JIP1 expression also prolonged Akt1 stimulation after a short IGF-1 pulse. The mechanism of JIP1-mediated Akt1 activation involved JIP1 protein binding to the Akt1 pleckstrin homology domain, which in turn promoted the phosphorylation of the activation T-loop of Akt1 by phosphoinositide-dependent kinase-1. These results suggest that, in certain cellular contexts, JIP1 may act as an Akt1 scaffold, which regulates the enzymatic activity of Akt1. This study also indicates that JIP1 expression can exert signaling effects independent of JNK activity.
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Affiliation(s)
- Albert H Kim
- Molecular Neurobiology Program, Skirball Institute for Biomolecular Medicine, Department of Cell Biology, New York University School of Medicine, New York, New York 10016, USA
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115
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Magara F, Haefliger JA, Thompson N, Riederer B, Welker E, Nicod P, Waeber G. Increased vulnerability to kainic acid-induced epileptic seizures in mice underexpressing the scaffold protein Islet-Brain 1/JIP-1. Eur J Neurosci 2003; 17:2602-10. [PMID: 12823467 DOI: 10.1046/j.1460-9568.2003.02701.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Islet-Brain 1, also known as JNK-interacting protein-1 (IB1/JIP-1) is a scaffold protein mainly involved in the regulation of the pro-apoptotic signalling cascade mediated by c-Jun-N-terminal kinase (JNK). IB1/JIP-1 organizes JNK and upstream kinases in a complex that facilitates JNK activation. However, overexpression of IB1/JIP-1 in neurons in vitro has been reported to result in inhibition of JNK activation and protection against cellular stress and apoptosis. The occurrence and the functional significance of stress-induced modulations of IB1/JIP-1 levels in vivo are not known. We investigated the regulation of IB1/JIP-1 in mouse hippocampus after systemic administration of kainic acid (KA), in wild-type mice as well as in mice hemizygous for the gene MAPK8IP1, encoding for IB1/JIP-1. We show here that IB1/JIP-1 is upregulated transiently in the hippocampus of normal mice, reaching a peak 8 h after seizure induction. Heterozygous mutant mice underexpressing IB1/JIP-1 showed a higher vulnerability to the epileptogenic properties of KA, whereas hippocampal IB1/JIP-1 levels remained unchanged after seizure induction. Subsequently, an increasing activation of JNK in the 8 h following seizure induction was observed in IB1/JIP-1 haploinsufficient mice, which also underwent more severe excitotoxic lesions in hippocampal CA3, as assessed histologically 3 days after KA administration. Taken together, these data indicate that IB1/JIP-1 in hippocampus participates in the regulation of the neuronal response to excitotoxic stress in a level-dependent fashion.
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Affiliation(s)
- Fulvio Magara
- Department of Internal Medicine, BH 10-640, University Hospital CHUV, 1011 Lausanne, Switzerland
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116
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Roehrich ME, Mooser V, Lenain V, Herz J, Nimpf J, Azhar S, Bideau M, Capponi A, Nicod P, Haefliger JA, Waeber G. Insulin-secreting beta-cell dysfunction induced by human lipoproteins. J Biol Chem 2003; 278:18368-75. [PMID: 12594227 DOI: 10.1074/jbc.m300102200] [Citation(s) in RCA: 152] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Diabetes is associated with significant changes in plasma concentrations of lipoproteins. We tested the hypothesis that lipoproteins modulate the function and survival of insulin-secreting cells. We first detected the presence of several receptors that participate in the binding and processing of plasma lipoproteins and confirmed the internalization of fluorescent low density lipoprotein (LDL) and high density lipoprotein (HDL) particles in insulin-secreting beta-cells. Purified human very low density lipoprotein (VLDL) and LDL particles reduced insulin mRNA levels and beta-cell proliferation and induced a dose-dependent increase in the rate of apoptosis. In mice lacking the LDL receptor, islets showed a dramatic decrease in LDL uptake and were partially resistant to apoptosis caused by LDL. VLDL-induced apoptosis of beta-cells involved caspase-3 cleavage and reduction in the levels of the c-Jun N-terminal kinase-interacting protein-1. In contrast, the proapoptotic signaling of lipoproteins was antagonized by HDL particles or by a small peptide inhibitor of c-Jun N-terminal kinase. The protective effects of HDL were mediated, in part, by inhibition of caspase-3 cleavage and activation of Akt/protein kinase B. In conclusion, human lipoproteins are critical regulators of beta-cell survival and may therefore contribute to the beta-cell dysfunction observed during the development of type 2 diabetes.
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Affiliation(s)
- Marc-Estienne Roehrich
- Department of Internal Medicine and Institute of Cellular Biology and Morphology, University Hospital, Lausanne 1011, Switzerland
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117
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Haefliger JA, Tawadros T, Meylan L, Gurun SL, Roehrich ME, Martin D, Thorens B, Waeber G. The scaffold protein IB1/JIP-1 is a critical mediator of cytokine-induced apoptosis in pancreatic beta cells. J Cell Sci 2003; 116:1463-9. [PMID: 12640031 DOI: 10.1242/jcs.00356] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In insulin-secreting cells, cytokines activate the c-Jun N-terminal kinase (JNK), which contributes to a cell signaling towards apoptosis. The JNK activation requires the presence of the murine scaffold protein JNK-interacting protein 1 (JIP-1) or human Islet-brain 1(IB1), which organizes MLK3, MKK7 and JNK for proper signaling specificity. Here, we used adenovirus-mediated gene transfer to modulate IB1/JIP-1 cellular content in order to investigate the contribution of IB1/JIP-1 to beta-cell survival. Exposure of the insulin-producing cell line INS-1 or isolated rat pancreatic islets to cytokines (interferon-gamma, tumor necrosis factor-alpha and interleukin-1beta) induced a marked reduction of IB1/JIP-1 content and a concomitant increase in JNK activity and apoptosis rate. This JNK-induced pro-apoptotic program was prevented in INS-1 cells by overproducing IB1/JIP-1 and this effect was associated with inhibition of caspase-3 cleavage. Conversely, reducing IB1/JIP-1 content in INS-1 cells and isolated pancreatic islets induced a robust increase in basal and cytokine-stimulated apoptosis. In heterozygous mice carrying a selective disruption of the IB1/JIP-1 gene, the reduction in IB1/JIP-1 content in happloinsufficient isolated pancreatic islets was associated with an increased JNK activity and basal apoptosis. These data demonstrate that modulation of the IB1-JIP-1 content in beta cells is a crucial regulator of JNK signaling pathway and of cytokine-induced apoptosis.
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118
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Helbecque N, Abderrahamani A, Meylan L, Riederer B, Mooser V, Miklossy J, Delplanque J, Boutin P, Nicod P, Haefliger JA, Cottel D, Amouyel P, Froguel P, Waeber G, Abderrhamani A. Islet-brain1/C-Jun N-terminal kinase interacting protein-1 (IB1/JIP-1) promoter variant is associated with Alzheimer's disease. Mol Psychiatry 2003; 8:413-22, 363. [PMID: 12740599 DOI: 10.1038/sj.mp.4001344] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Islet-brain1 (IB1) or c-Jun NH2 terminal kinase interacting protein-1 (JIP-1), the product of the MAPK8IP1 gene, functions as a neuronal scaffold protein to allow signalling specificity. IB1/JIP-1 interacts with many cellular components including the reelin receptor ApoER2, the low-density lipoprotein receptor-related protein (LRP), kinesin and the Alzheimer's amyloid precursor protein. Coexpression of IB1/JIP-1 with other components of the c-Jun NH2 terminal-kinase (JNK) pathway activates the JNK activity; conversely, selective disruption of IB1/JIP-1 in mice reduces the stress-induced apoptosis of neuronal cells. We therefore hypothesized that IB1/JIP-1 is a risk factor for Alzheimer's disease (AD). By immunocytochemistry, we first colocalized the presence of IB1/JIP-1 with JNK and phosphorylated tau in neurofibrillary tangles. We next identified a -499A>G polymorphism in the 5' regulatory region of the MAPK8IP1 gene. In two separate French populations the -499A>G polymorphism of MAPK8IP1 was not associated with an increased risk to AD. However, when stratified on the +766C>T polymorphism of exon 3 of the LRP gene, the IB1/JIP-1 polymorphism was strongly associated with AD in subjects bearing the CC genotype in the LRP gene. The functional consequences of the -499A>G polymorphism of MAPK8IP1 was investigated in vitro. In neuronal cells, the G allele increased transcriptional activity and was associated with an enhanced binding activity. Taken together, these data indicate that the increased transcriptional activity in the presence of the G allele of MAPK8IP1 is a risk factor to the onset of in patients bearing the CC genotype of the LRP gene.
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Affiliation(s)
- N Helbecque
- Institut National de la Santé et de la Recherche Médicale U508, Pasteur Institute, Lille, France
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119
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Abstract
A precise knowledge of the defects underlying type 1 and type 2 diabetes is essential for designing appropriate therapeutic strategies. Because experiments in humans are limited, naturally occurring, and especially genetically engineered rodent models, have revolutionized research in diabetes. We review some of the models created recently and discuss their impact on human diabetes.
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Affiliation(s)
- Rohit N Kulkarni
- Joslin Diabetes Center, One Joslin Place, Room 602, Boston, MA 02215, USA.
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120
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Hirosumi J, Tuncman G, Chang L, Görgün CZ, Uysal KT, Maeda K, Karin M, Hotamisligil GS. A central role for JNK in obesity and insulin resistance. Nature 2002; 420:333-6. [PMID: 12447443 DOI: 10.1038/nature01137] [Citation(s) in RCA: 2395] [Impact Index Per Article: 108.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2002] [Accepted: 09/03/2002] [Indexed: 11/09/2022]
Abstract
Obesity is closely associated with insulin resistance and establishes the leading risk factor for type 2 diabetes mellitus, yet the molecular mechanisms of this association are poorly understood. The c-Jun amino-terminal kinases (JNKs) can interfere with insulin action in cultured cells and are activated by inflammatory cytokines and free fatty acids, molecules that have been implicated in the development of type 2 diabetes. Here we show that JNK activity is abnormally elevated in obesity. Furthermore, an absence of JNK1 results in decreased adiposity, significantly improved insulin sensitivity and enhanced insulin receptor signalling capacity in two different models of mouse obesity. Thus, JNK is a crucial mediator of obesity and insulin resistance and a potential target for therapeutics.
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Affiliation(s)
- Jiro Hirosumi
- Division of Biological Sciences and Department of Nutrition, Harvard School of Public Health, 665 Huntington Avenue, Boston, Massachusetts 02115, USA
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121
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Ozcan S, Mosley AL, Aryal BK. Functional expression and analysis of the pancreatic transcription factor PDX-1 in yeast. Biochem Biophys Res Commun 2002; 295:724-9. [PMID: 12099699 DOI: 10.1016/s0006-291x(02)00747-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The pancreas-specific transcription factor Pdx-1 is important for pancreas development and beta-cell specific gene expression in insulin-producing cells. We have expressed the mouse PDX-1 gene in the yeast Saccharomyces cerevisiae and characterized its functional domains. Pdx-1 functions as a strong activator in yeast and stimulates gene expression by more than 80-fold. The transcriptional activation domain of Pdx-1 is located within the first 144 amino-terminal amino acids. Pdx-1 is also able to bind and activate transcription from the A3 element of the human insulin gene promoter in yeast. Analysis of the effects of two-point mutations (Q59L and R197H) in the PDX-1 gene found in type II diabetes patients showed that both point mutations interfere with the ability of Pdx-1 to bind to DNA and to activate transcription in yeast.
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Affiliation(s)
- Sabire Ozcan
- Department of Molecular and Cellular Biochemistry, Chandler Medical Center, University of Kentucky, 800 Rose Street, Lexington 40536, USA.
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122
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Abstract
Maturity-onset diabetes of the young (MODY) are monogenic forms of type 2 diabetes that are characterized by an early disease onset, autosomal-dominant inheritance, and defects in insulin secretion. Genetic studies have identified mutations in at least eight genes associated with different forms of MODY. The majority of the MODY subtypes are caused by mutations in transcription factors that include hepatocyte nuclear factor (HNF)-4 alpha, HNF-1 alpha, PDX-1, HNF-1 beta, and NEURO-DI/BETA-2. In addition, genetic defects in the glucokinase gene, the glucose sensor of the pancreatic beta cells, and the insulin gene also lead to impaired glucose tolerance. Biochemical and genetic studies have demonstrated that the MODY genes are functionally related and form an integrated transcriptional network that is important for many metabolic pathways.
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Affiliation(s)
- David Q Shih
- Laboratory of Metabolic Diseases, Rockefeller University, 1230 York Avenue, Box 292, New York, NY 10021, USA
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123
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Hashimoto M, Hsu LJ, Rockenstein E, Takenouchi T, Mallory M, Masliah E. alpha-Synuclein protects against oxidative stress via inactivation of the c-Jun N-terminal kinase stress-signaling pathway in neuronal cells. J Biol Chem 2002; 277:11465-72. [PMID: 11790792 DOI: 10.1074/jbc.m111428200] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The expression of alpha-synuclein, a synaptic molecule implicated in the pathogenesis of neurodegenerative disorders such as Parkinson's disease and Lewy body disease is increased upon injury to the nervous system, indicating that it might play a role in regeneration and plasticity; however, the mechanisms are unclear. Because c-Jun N-terminal kinase (JNK), a member of the mitogen-activated protein kinase family, plays an important role in stress response, the main objective of the present study was to better understand the involvement of this pathway in the signaling responses associated with resistance to injury in cells expressing alpha-synuclein. For this purpose, the JNK-signaling pathway was investigated in alpha-synuclein-transfected neuronal cell line glucose transporter (GT) 1-7 under oxidative stress conditions. Although hydrogen peroxide challenge resulted in JNK activation and cell death in cells transfected with vector control or beta-synuclein, alpha-synuclein-transfected cells were resistant to hydrogen peroxide, and JNK was not activated. The inactivation of JNK in the alpha-synuclein-transfected cells was associated with increased expression and activity of JNK-interacting protein (JIP)-1b/islet-brain (IB)1, the scaffold protein for the JNK pathway. Similarly, cells transfected with JIP-1b/IB1 were resistant to hydrogen peroxide associated with inactivation of the JNK pathway. In these cells, expression of endogenous alpha-synuclein was significantly increased at the protein level. Furthermore, alpha-synuclein was co-localized with JIP-1b/IB1 in the growth cones. Taken together, these results suggest that increased alpha-synuclein expression might protect cells from oxidative stress by inactivation of JNK via increased expression of JIP-1b/IB1. Furthermore, interactions between alpha-synuclein and JIP-1b/IB1 may play a mutual role in the neuronal response to injury and neurodegeneration.
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Affiliation(s)
- Makoto Hashimoto
- Department of Neurosciences, University of California San Diego, School of Medicine, La Jolla, California 92093-0624, USA
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124
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Scheinfeld MH, Roncarati R, Vito P, Lopez PA, Abdallah M, D'Adamio L. Jun NH2-terminal kinase (JNK) interacting protein 1 (JIP1) binds the cytoplasmic domain of the Alzheimer's beta-amyloid precursor protein (APP). J Biol Chem 2002; 277:3767-75. [PMID: 11724784 DOI: 10.1074/jbc.m108357200] [Citation(s) in RCA: 128] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The familial Alzheimer's disease gene product amyloid beta precursor protein (APP) is sequentially processed by beta- and gamma-secretases to generate the Abeta peptide. The biochemical pathway leading to Abeta formation has been extensively studied since extracellular aggregates of Abeta peptides are considered the culprit of Alzheimer's disease. Aside from its pathological relevance, the biological role of APP processing is unknown. Cleavage of APP by gamma-secretase releases, together with Abeta, a COOH-terminal APP intracellular domain, termed AID. This peptide has recently been identified in brain tissue of normal control and patients with sporadic Alzheimer's disease. We have previously shown that AID acts as a positive regulator of apoptosis. Nevertheless, the molecular mechanism by which AID regulates this process remains unknown. Hoping to gain clues about the function of APP, we used the yeast two-hybrid system to identify interaction between the AID region of APP and JNK-interacting protein-1 (JIP1). This molecular interaction is confirmed in vitro, in vivo by fluorescence resonance energy transfer (FRET), and in mouse brain lysates. These data provide a link between APP and its processing by gamma-secretase, and stress kinase signaling pathways. These pathways are known regulators of apoptosis and may be involved in the pathogenesis of Alzheimer's disease.
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Affiliation(s)
- Meir H Scheinfeld
- Albert Einstein College of Medicine, Department of Microbiology & Immunology, Bronx, New York 10461, USA
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125
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Tawadros T, Formenton A, Dudler J, Thompson N, Nicod P, Leisinger HJ, Waeber G, Haefliger JA. The scaffold protein IB1/JIP-1 controls the activation of JNK in rat stressed urothelium. J Cell Sci 2002; 115:385-93. [PMID: 11839789 DOI: 10.1242/jcs.115.2.385] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The c-Jun N-terminal kinase (JNK) is critical for cell survival, differentiation, apoptosis and tumorigenesis. This signalling pathway requires the presence of the scaffold protein Islet-Brain1/c-Jun N-terminal kinase interacting protein-1 (IB1/JIP-1). Immunolabeling and in situ hybridisation of bladder sections showed that IB1/JIP-1 is expressed in urothelial cells. The functional role of IB1/JIP-1 in the urothelium was therefore studied in vivo in a model of complete rat bladder outlet obstruction. This parietal stress, which is due to urine retention, reduced the content of IB1/JIP-1 in urothelial cells and consequently induced a drastic increase in JNK activity and AP-1 binding activity. Using a viral gene transfer approach, the stress-induced activation of JNK was prevented by overexpressing IB1/JIP-1. Conversely, the JNK activity was increased in urothelial cells where the IB1/JIP-1 content was experimentally reduced using an antisense RNA strategy. Furthermore, JNK activation was found to be increased in non-stressed urothelial cells of heterozygous mice carrying a selective disruption of the IB1/JIP-1 gene. These data established that mechanical stress in urothelial cells in vivo induces a robust JNK activation as a consequence of regulated expression of the scaffold protein IB1/JIP-1. This result highlights a critical role for that scaffold protein in the homeostasis of the urothelium and unravels a new potential target to regulate the JNK pathway in this tissue.
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Affiliation(s)
- Thomas Tawadros
- Department of Internal Medicine, Service of Urology, University Hospital, CHUV-1011 Lausanne, Switzerland
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126
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Abderrahmani A, Steinmann M, Plaisance V, Niederhauser G, Haefliger JA, Mooser V, Bonny C, Nicod P, Waeber G. The transcriptional repressor REST determines the cell-specific expression of the human MAPK8IP1 gene encoding IB1 (JIP-1). Mol Cell Biol 2001; 21:7256-67. [PMID: 11585908 PMCID: PMC99900 DOI: 10.1128/mcb.21.21.7256-7267.2001] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Islet-brain 1 (IB1) is the human and rat homologue of JIP-1, a scaffold protein interacting with the c-Jun amino-terminal kinase (JNK). IB1 expression is mostly restricted to the endocrine pancreas and to the central nervous system. Herein, we explored the transcriptional mechanism responsible for this preferential islet and neuronal expression of IB1. A 731-bp fragment of the 5' regulatory region of the human MAPK8IP1 gene was isolated from a human BAC library and cloned upstream of a luciferase reporter gene. This construct drove high transcriptional activity in both insulin-secreting and neuron-like cells but not in unrelated cell lines. Sequence analysis of this promoter region revealed the presence of a neuron-restrictive silencer element (NRSE) known to bind repressor zinc finger protein REST. This factor is not expressed in insulin-secreting and neuron-like cells. By mobility shift assay, we confirmed that REST binds to the NRSE present in the IB1 promoter. Once transiently transfected in beta-cell lines, the expression vector encoding REST repressed IB1 transcriptional activity. The introduction of a mutated NRSE in the 5' regulating region of the IB1 gene abolished the repression activity driven by REST in insulin-secreting beta cells and relieved the low transcriptional activity of IB1 observed in unrelated cells. Moreover, transfection in non-beta and nonneuronal cell lines of an expression vector encoding REST lacking its transcriptional repression domain relieved IB1 promoter activity. Last, the REST-mediated repression of IB1 could be abolished by trichostatin A, indicating that deacetylase activity is required to allow REST repression. Taken together, these data establish a critical role for REST in the control of the tissue-specific expression of the human IB1 gene.
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Affiliation(s)
- A Abderrahmani
- Department of Internal Medicine, CHUV-University Hospital, Lausanne, Switzerland
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127
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Sreekumar KR, Aravind L, Koonin EV. Computational analysis of human disease-associated genes and their protein products. Curr Opin Genet Dev 2001; 11:247-57. [PMID: 11377959 DOI: 10.1016/s0959-437x(00)00186-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The complete genome sequences for human, Drosophila melanogaster and Arabidopsis thaliana have been reported recently. With the availability of complete sequences for many bacteria and archaea, and five eukaryotes, comparative genomics and sequence analysis are enabling us to identify counterparts of many human disease genes in model organisms, which in turn should accelerate the pace of research and drug development to combat human diseases. Continuous improvement of specialized protein databases, together with sensitive computational tools, have enhanced the power and reliability of computational prediction of protein function.
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Affiliation(s)
- K R Sreekumar
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894, USA
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128
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c-Jun N-terminal kinase (JNK)-interacting protein-1b/islet-brain-1 scaffolds Alzheimer's amyloid precursor protein with JNK. J Neurosci 2001. [PMID: 11517249 DOI: 10.1523/jneurosci.21-17-06597.2001] [Citation(s) in RCA: 138] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Using a yeast two-hybrid method, we searched for amyloid precursor protein (APP)-interacting molecules by screening mouse and human brain libraries. In addition to known interacting proteins containing a phosphotyrosine-interaction-domain (PID)-Fe65, Fe65L, Fe65L2, X11, and mDab1, we identified, as a novel APP-interacting molecule, a PID-containing isoform of mouse JNK-interacting protein-1 (JIP-1b) and its human homolog IB1, the established scaffold proteins for JNK. The APP amino acids Tyr(682), Asn(684), and Tyr(687) in the G(681)YENPTY(687) region were all essential for APP/JIP-1b interaction, but neither Tyr(653) nor Thr(668) was necessary. APP-interacting ability was specific for this additional isoform containing PID and was shared by both human and mouse homologs. JIP-1b expressed by mammalian cells was efficiently precipitated by the cytoplasmic domain of APP in the extreme Gly(681)-Asn(695) domain-dependent manner. Reciprocally, both full-length wild-type and familial Alzheimer's disease mutant APPs were precipitated by PID-containing JIP constructs. Antibodies raised against the N and C termini of JIP-1b coprecipitated JIP-1b and wild-type or mutant APP in non-neuronal and neuronal cells. Moreover, human JNK1beta1 formed a complex with APP in a JIP-1b-dependent manner. Confocal microscopic examination demonstrated that APP and JIP-1b share similar subcellular localization in transfected cells. These data indicate that JIP-1b/IB1 scaffolds APP with JNK, providing a novel insight into the role of the JNK scaffold protein as an interface of APP with intracellular functional molecules.
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129
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Whitmarsh AJ, Kuan CY, Kennedy NJ, Kelkar N, Haydar TF, Mordes JP, Appel M, Rossini AA, Jones SN, Flavell RA, Rakic P, Davis RJ. Requirement of the JIP1 scaffold protein for stress-induced JNK activation. Genes Dev 2001; 15:2421-32. [PMID: 11562351 PMCID: PMC312784 DOI: 10.1101/gad.922801] [Citation(s) in RCA: 186] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The c-Jun N-terminal kinase (JNK) signal transduction pathway is activated in response to the exposure of cells to environmental stress. Components of the JNK signaling pathway interact with the JIP1 scaffold protein. JIP1 is located in the neurites of primary hippocampal neurons. However, in response to stress, JIP1 accumulates in the soma together with activated JNK and phosphorylated c-Jun. Disruption of the Jip1 gene in mice by homologous recombination prevented JNK activation caused by exposure to excitotoxic stress and anoxic stress in vivo and in vitro. These data show that the JIP1 scaffold protein is a critical component of a MAP-kinase signal transduction pathway.
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Affiliation(s)
- A J Whitmarsh
- Howard Hughes Medical Institute and Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
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130
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van Tilburg J, van Haeften TW, Pearson P, Wijmenga C. Defining the genetic contribution of type 2 diabetes mellitus. J Med Genet 2001; 38:569-78. [PMID: 11546824 PMCID: PMC1734947 DOI: 10.1136/jmg.38.9.569] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Type 2 diabetes mellitus is a common multifactorial genetic syndrome, which is determined by several different genes and environmental factors. It now affects 150 million people world wide but its incidence is increasing rapidly because of secondary factors, such as obesity, hypertension, and lack of physical activity. Many studies have been carried out to determine the genetic factors involved in type 2 diabetes mellitus. In this review we look at the different strategies used and discuss the genome wide scans performed so far in more detail. New technologies, such as microarrays, and the discovery of SNPs will lead to a greater understanding of the pathogenesis of type 2 diabetes mellitus and to better diagnostics, treatment, and eventually prevention.
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Affiliation(s)
- J van Tilburg
- Department of Medical Genetics, KC.04.084.2, University Medical Centre Utrecht, 3508 AB Utrecht, The Netherlands
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131
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Thompson NA, Haefliger JA, Senn A, Tawadros T, Magara F, Ledermann B, Nicod P, Waeber G. Islet-brain1/JNK-interacting protein-1 is required for early embryogenesis in mice. J Biol Chem 2001; 276:27745-8. [PMID: 11390367 DOI: 10.1074/jbc.c100222200] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Islet-brain1/JNK-interacting protein-1 (IB1/JIP-1) is a scaffold protein that organizes the JNK, MKK7, and MLK1 to allow signaling specificity. Targeted disruption of the gene MAPK8IP1 encoding IB1/JIP-1 in mice led to embryonic death prior to blastocyst implantation. In culture, no IB1/JIP-1(-/-) embryos were identified indicating that accelerated cell death occurred during the first cell cycles. IB1/JIP-1 expression was detected in unfertilized oocytes, in spermatozoa, and in different stages of embryo development. Thus, despite the maternal and paternal transmission of the IB1/JIP-1 protein, early transcription of the MAPK8IP1 gene is required for the survival of the fertilized oocytes.
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Affiliation(s)
- N A Thompson
- Department of Internal Medicine and Institute of Cellular Biology and Morphology and the Reproductive Medicine Unit, CHUV-University Hospital, 1011 Lausanne, Switzerland
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132
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Froguel P, Velho G. Maturity Onset Diabetes of the Young (Mody). GENETICS OF DIABETES MELLITUS 2001. [DOI: 10.1007/978-1-4615-1597-5_5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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133
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Bonny C, Oberson A, Negri S, Sauser C, Schorderet DF. Cell-permeable peptide inhibitors of JNK: novel blockers of beta-cell death. Diabetes 2001; 50:77-82. [PMID: 11147798 DOI: 10.2337/diabetes.50.1.77] [Citation(s) in RCA: 491] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Stress conditions and proinflammatory cytokines activate the c-Jun NH2-terminal kinase (JNK), a member of the stress-activated group of mitogen-activated protein kinases (MAPKs). We recently demonstrated that inhibition of JNK signaling with the use of the islet-brain (IB) 1 and 2 proteins prevented interleukin (IL)-1beta-induced pancreatic beta-cell death. Bioactive cell-permeable peptide inhibitors of JNK were engineered by linking the minimal 20-amino acid inhibitory domains of the IB proteins to the 10-amino acid HIV-TAT sequence that rapidly translocates inside cells. Kinase assays indicate that the inhibitors block activation of the transcription factor c-Jun by JNK. Addition of the peptides to the insulin-secreting betaTC-3 cell line results in a marked inhibition of IL-1beta-induced c-jun and c-fos expression. The peptides protect betaTC-3 cells against apoptosis induced by IL-1beta. All-D retro-inverso peptides penetrate cells as efficiently as the L-enantiomers, decrease c-Jun activation by JNK, and remain highly stable inside cells. These latter peptides confer full protection against IL-1beta-induced apoptosis for up to 2 weeks of continual treatment with IL-1beta. These data establish these bioactive cell-permeable peptides as potent pharmacological compounds that decrease intracellular JNK signaling and confer long-term protection to pancreatic beta-cells from IL-1beta-induced apoptosis.
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Affiliation(s)
- C Bonny
- Division of Medical Genetics, Centre Hospitalier Universitaire Vaudois-University Hospital, Lausanne, Switzerland.
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135
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Dupraz P, Cottet S, Hamburger F, Dolci W, Felley-Bosco E, Thorens B. Dominant negative MyD88 proteins inhibit interleukin-1beta /interferon-gamma -mediated induction of nuclear factor kappa B-dependent nitrite production and apoptosis in beta cells. J Biol Chem 2000; 275:37672-8. [PMID: 10967106 DOI: 10.1074/jbc.m005150200] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Insulin-dependent diabetes mellitus is an autoimmune disease in which pancreatic islet beta cells are destroyed by a combination of immunological and inflammatory mechanisms. In particular, cytokine-induced production of nitric oxide has been shown to correlate with beta cell apoptosis and/or inhibition of insulin secretion. In the present study, we investigated whether the interleukin (IL)-1beta intracellular signal transduction pathway could be blocked by overexpression of dominant negative forms of the IL-1 receptor interacting protein MyD88. We show that overexpression of the Toll domain or the lpr mutant of MyD88 in betaTc-Tet cells decreased nuclear factor kappaB (NF-kappaB) activation upon IL-1beta and IL-1beta/interferon (IFN)-gamma stimulation. Inducible nitric oxide synthase mRNA accumulation and nitrite production, which required the simultaneous presence of IL-1beta and IFN-gamma, were also suppressed by approximately 70%, and these cells were more resistant to cytokine-induced apoptosis as compared with parental cells. The decrease in glucose-stimulated insulin secretion induced by IL-1beta and IFN-gamma was however not prevented. This was because these dysfunctions were induced by IFN-gamma alone, which decreased cellular insulin content and stimulated insulin exocytosis. These results demonstrate that IL-1beta is involved in inducible nitric oxide synthase gene expression and induction of apoptosis in mouse beta cells but does not contribute to impaired glucose-stimulated insulin secretion. Furthermore, our data show that IL-1beta cellular actions can be blocked by expression of MyD88 dominant negative proteins and, finally, that cytokine-induced beta cell secretory dysfunctions are due to the action of IFN-gamma.
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Affiliation(s)
- P Dupraz
- Institute of Pharmacology and Toxicology, University of Lausanne, 27 Rue du Bugnon, 1005 Lausanne, Switzerland
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136
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Affiliation(s)
- R J Davis
- Howard Hughes Medical Institute, Department of Biochemistry and Molecular Biology, University of Massachusetts Medical School, Worcester 01605, USA.
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Bonny C, Oberson A, Steinmann M, Schorderet DF, Nicod P, Waeber G. IB1 reduces cytokine-induced apoptosis of insulin-secreting cells. J Biol Chem 2000; 275:16466-72. [PMID: 10748095 DOI: 10.1074/jbc.m908297199] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
IB1/JIP-1 is a scaffold protein that interacts with upstream components of the c-Jun N-terminal kinase (JNK) signaling pathway. IB1 is expressed at high levels in pancreatic beta cells and may therefore exert a tight control on signaling events mediated by JNK in these cells. Activation of JNK by interleukin 1 (IL-1beta) or by the upstream JNK constitutive activator DeltaMEKK1 promoted apoptosis in two pancreatic beta cell lines and decreased IB1 content by 50-60%. To study the functional consequences of the reduced IB1 content in beta cell lines, we used an insulin-secreting cell line expressing an inducible IB1 antisense RNA that lead to a 38% IB1 decrease. Reducing IB1 levels in these cells increased phosphorylation of c-Jun and increased the apoptotic rate in presence of IL-1beta. Nitric oxide production was not stimulated by expression of the IB1 antisense RNA. Complementary experiments indicated that overexpression of IB1 in insulin-producing cells prevented JNK-mediated activation of the transcription factors c-Jun, ATF2, and Elk1 and decreased IL-1beta- and DeltaMEKK1-induced apoptosis. These data indicate that IB1 plays an anti-apoptotic function in insulin-producing cells probably by controlling the activity of the JNK signaling pathway.
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Affiliation(s)
- C Bonny
- Division of Medical Genetics and the Department of Internal Medicine, CHUV University Hospital, 1011 Lausanne Switzerland.
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