Dataset Information

JNK1 Deficient Insulin-Producing Cells Are Protected against Interleukin-1?-Induced Apoptosis Associated with Abrogated Myc Expression.

ABSTRACT: The relative contributions of the JNK subtypes in inflammatory ?-cell failure and apoptosis are unclear. The JNK protein family consists of JNK1, JNK2, and JNK3 subtypes, encompassing many different isoforms. INS-1 cells express JNK1?1, JNK1?2, JNK1?1, JNK1?2, JNK2?1, JNK2?2, JNK3?1, and JNK3?2 mRNA isoform transcripts translating into 46 and 54?kDa isoform JNK proteins. Utilizing Lentiviral mediated expression of shRNAs against JNK1, JNK2, or JNK3 in insulin-producing INS-1 cells, we investigated the role of individual JNK subtypes in IL-1?-induced ?-cell apoptosis. JNK1 knockdown prevented IL-1?-induced INS-1 cell apoptosis associated with decreased 46?kDa isoform JNK protein phosphorylation and attenuated Myc expression. Transient knockdown of Myc also prevented IL-1?-induced apoptosis as well as caspase 3 cleavage. JNK2 shRNA potentiated IL-1?-induced apoptosis and caspase 3 cleavage, whereas JNK3 shRNA did not affect IL-1?-induced ?-cell death compared to nonsense shRNA expressing INS-1 cells. In conclusion, JNK1 mediates INS-1 cell death associated with increased Myc expression. These findings underline the importance of differentiated targeting of JNK subtypes in the development of inflammatory ?-cell failure and destruction.

SUBMITTER: Prause M

PROVIDER: S-EPMC4745310 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

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JNK1 Deficient Insulin-Producing Cells Are Protected against Interleukin-1β-Induced Apoptosis Associated with Abrogated Myc Expression.

Prause Michala M Mayer Christopher Michael CM Brorsson Caroline C Frederiksen Klaus Stensgaard KS Billestrup Nils N Størling Joachim J Mandrup-Poulsen Thomas T

Journal of diabetes research 20160110

The relative contributions of the JNK subtypes in inflammatory β-cell failure and apoptosis are unclear. The JNK protein family consists of JNK1, JNK2, and JNK3 subtypes, encompassing many different isoforms. INS-1 cells express JNK1α1, JNK1α2, JNK1β1, JNK1β2, JNK2α1, JNK2α2, JNK3α1, and JNK3α2 mRNA isoform transcripts translating into 46 and 54 kDa isoform JNK proteins. Utilizing Lentiviral mediated expression of shRNAs against JNK1, JNK2, or JNK3 in insulin-producing INS-1 cells, we investigat ...[more]

PMID: 26962537

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Project description:OBJECTIVE:The nuclear receptor TAK1/TR4/NR2C2 is expressed in several tissues that are important in the control of energy homeostasis. In this study, we investigate whether TAK1 functions as a regulator of lipid and energy homeostasis and has a role in metabolic syndrome. RESEARCH DESIGN AND METHODS:We generated TAK1-deficient (TAK1?(/)?) mice to study the function of TAK1 in the development of metabolic syndrome in aged mice and mice fed a high-fat diet (HFD). (Immuno)histochemical, biochemical, and gene expression profile analyses were performed to determine the effect of the loss of TAK1 expression on lipid homeostasis in liver and adipose tissues. In addition, insulin sensitivity, energy expenditure, and adipose-associated inflammation were compared in wild-type (WT) and TAK1?(/)? mice fed a HFD. RESULTS:TAK1-deficient (TAK1?(/)?) mice are resistant to the development of age- and HFD-induced metabolic syndrome. Histo- and biochemical analyses showed significantly lower hepatic triglyceride levels and reduced lipid accumulation in adipose tissue in TAK1?(/)? mice compared with WT mice. Gene expression profiling analysis revealed that the expression of several genes encoding proteins involved in lipid uptake and triglyceride synthesis and storage, including Cidea, Cidec, Mogat1, and CD36, was greatly decreased in the liver and primary hepatocytes of TAK1?(/)? mice. Restoration of TAK1 expression in TAK1?(/)? hepatocytes induced expression of several lipogenic genes. Moreover, TAK1?(/)? mice exhibited reduced infiltration of inflammatory cells and expression of inflammatory genes in white adipose tissue, and were resistant to the development of glucose intolerance and insulin resistance. TAK1?(/)? mice consume more oxygen and produce more carbon dioxide than WT mice, suggesting increased energy expenditure. CONCLUSIONS:Our data reveal that TAK1 plays a critical role in the regulation of energy and lipid homeostasis, and promotes the development of metabolic syndrome. TAK1 may provide a new therapeutic target in the management of obesity, diabetes, and liver steatosis.

Project description:BackgroundThe leucine-rich repeats and immunoglobulin-like domains (LRIG) proteins constitute an integral membrane protein family that has three members: LRIG1, LRIG2, and LRIG3. LRIG1 negatively regulates growth factor signaling, but little is known regarding the functions of LRIG2 and LRIG3. In oligodendroglial brain tumors, high expression of LRIG2 correlates with poor patient survival. Lrig1 and Lrig3 knockout mice are viable, but there have been no reports on Lrig2-deficient mice to date.Methodology/principal findingsLrig2-deficient mice were generated by the ablation of Lrig2 exon 12 (Lrig2E12). The Lrig2E12-/- mice showed a transiently reduced growth rate and an increased spontaneous mortality rate; 20-25% of these mice died before 130 days of age, with the majority of the deaths occurring before 50 days. Ntv-a transgenic mice with different Lrig2 genotypes were transduced by intracranial injection with platelet-derived growth factor (PDGF) B-encoding replication-competent avian retrovirus (RCAS)-producing DF-1 cells. All injected Lrig2E12+/+ mice developed Lrig2 expressing oligodendroglial brain tumors of lower grade (82%) or glioblastoma-like tumors of higher grade (18%). Lrig2E12-/- mice, in contrast, only developed lower grade tumors (77%) or had no detectable tumors (23%). Lrig2E12-/- mouse embryonic fibroblasts (MEF) showed altered induction-kinetics of immediate-early genes Fos and Egr2 in response to PDGF-BB stimulation. However, Lrig2E12-/- MEFs showed no changes in Pdgfr? or Pdgfr? levels or in levels of PDGF-BB-induced phosphorylation of Pdgfr?, Pdgfr?, Akt, or extracellular signal-regulated protein kinases 1 and 2 (ERK1/2). Overexpression of LRIG1, but not of LRIG2, downregulated PDGFR? levels in HEK-293T cells.ConclusionsThe phenotype of Lrig2E12-/- mice showed that Lrig2 was a promoter of PDGFB-induced glioma, and Lrig2 appeared to have important molecular and developmental functions that were distinct from those of Lrig1 and Lrig3.

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Dataset Information

JNK1 Deficient Insulin-Producing Cells Are Protected against Interleukin-1?-Induced Apoptosis Associated with Abrogated Myc Expression.

Publications

JNK1 Deficient Insulin-Producing Cells Are Protected against Interleukin-1β-Induced Apoptosis Associated with Abrogated Myc Expression.

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