Hongliang Xu, A. V. Hertzel, K. Steen, D. Bernlohr
Activation of proinflammatory macrophages plays an important role in the pathogenesis of insulin resistance, type 2 diabetes, and atherosclerosis. Previous work using high fat-fed mice has shown that ablation of the adipocyte fatty acid binding protein (FABP4/aP2) in macrophages leads to an antiinflammatory state both in situ and in vivo, and the mechanism is linked, in part, to increased intracellular monounsaturated fatty acids and the up-regulation of uncoupling protein 2. Here, we show that loss of FABP4/aP2 in macrophages additionally induces sirtuin 3 (SIRT3) expression and that monounsaturated fatty acids (C16:1, C18:1) lead to increased SIRT3 protein expression. Increased expression of SirT3 in FABP4/aP2 null macrophages occurs at the protein level with no change in SirT3 mRNA. When compared with controls, silencing of SIRT3 in Raw246.7 macrophages leads to increased expression of inflammatory cytokines, inducible nitric oxide synthase and cyclooxygenase 2. In contrast, loss of SIRT3 in FABP4/aP2-deficient macrophages attenuates the suppressed inflammatory signaling, reduced reactive oxygen species production, lipopolysaccharide-induced mitochondrial dysfunction, and increased fatty acid oxidation. These results suggest that the antiinflammatory phenotype of FABP4/aP2 null mice is mediated by increased intracellular monounsaturated fatty acids leading to the increased expression of both uncoupling protein 2 and SirT3.
{"title":"Loss of Fatty Acid Binding Protein 4/aP2 Reduces Macrophage Inflammation Through Activation of SIRT3.","authors":"Hongliang Xu, A. V. Hertzel, K. Steen, D. Bernlohr","doi":"10.1210/me.2015-1301","DOIUrl":"https://doi.org/10.1210/me.2015-1301","url":null,"abstract":"Activation of proinflammatory macrophages plays an important role in the pathogenesis of insulin resistance, type 2 diabetes, and atherosclerosis. Previous work using high fat-fed mice has shown that ablation of the adipocyte fatty acid binding protein (FABP4/aP2) in macrophages leads to an antiinflammatory state both in situ and in vivo, and the mechanism is linked, in part, to increased intracellular monounsaturated fatty acids and the up-regulation of uncoupling protein 2. Here, we show that loss of FABP4/aP2 in macrophages additionally induces sirtuin 3 (SIRT3) expression and that monounsaturated fatty acids (C16:1, C18:1) lead to increased SIRT3 protein expression. Increased expression of SirT3 in FABP4/aP2 null macrophages occurs at the protein level with no change in SirT3 mRNA. When compared with controls, silencing of SIRT3 in Raw246.7 macrophages leads to increased expression of inflammatory cytokines, inducible nitric oxide synthase and cyclooxygenase 2. In contrast, loss of SIRT3 in FABP4/aP2-deficient macrophages attenuates the suppressed inflammatory signaling, reduced reactive oxygen species production, lipopolysaccharide-induced mitochondrial dysfunction, and increased fatty acid oxidation. These results suggest that the antiinflammatory phenotype of FABP4/aP2 null mice is mediated by increased intracellular monounsaturated fatty acids leading to the increased expression of both uncoupling protein 2 and SirT3.","PeriodicalId":18812,"journal":{"name":"Molecular endocrinology","volume":"10 1","pages":"325-34"},"PeriodicalIF":0.0,"publicationDate":"2016-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1210/me.2015-1301","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66016519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lei Yang, D. Yao, Haiyuan Yang, Ying-jie Wei, Yunru Peng, Yongfang Ding, L. Shu
Diabetes is characterized by a loss and dysfunction of the β-cell. Glucagon-like peptide 1 receptor (GLP-1R) signaling plays an important role in β-cell survival and function. It is meaningful to identify promising agents from natural products which might activate GLP-1R signaling. In this study, puerarin, a diet isoflavone, was evaluated its beneficial effects on β-cell survival and GLP-1R pathway. We showed that puerarin reduced the body weight gain, normalized blood glucose, and improved glucose tolerance in high-fat diet-induced and db/db diabetic mice. Most importantly, increased β-cell mass and β-cell proliferation but decreased β-cell apoptosis were observed in puerarin-treated diabetic mice as examined by immunostaining of mice pancreatic sections. The protective effect of puerarin on β-cell survival was confirmed in isolated mouse islets treated with high glucose. Further mechanism studies showed that the circulating level of GLP-1 in mice was unaffected by puerarin. However, puerarin enhanced GLP-1R signaling by up-regulating expressions of GLP-1R and pancreatic and duodenal homeobox 1, which subsequently led to protein kinase B (Akt) activation but forkhead box O1 inactivation, and promoted β-cell survival. The protective effect of puerarin was remarkably suppressed by Exendin(9-39), an antagonist of GLP-1R. Our study demonstrated puerarin improved glucose homeostasis in obese diabetic mice and identified a novel role of puerarin in protecting β-cell survival by mechanisms involving activation of GLP-1R signaling and downstream targets.
{"title":"Puerarin Protects Pancreatic β-Cells in Obese Diabetic Mice via Activation of GLP-1R Signaling.","authors":"Lei Yang, D. Yao, Haiyuan Yang, Ying-jie Wei, Yunru Peng, Yongfang Ding, L. Shu","doi":"10.1210/me.2015-1213","DOIUrl":"https://doi.org/10.1210/me.2015-1213","url":null,"abstract":"Diabetes is characterized by a loss and dysfunction of the β-cell. Glucagon-like peptide 1 receptor (GLP-1R) signaling plays an important role in β-cell survival and function. It is meaningful to identify promising agents from natural products which might activate GLP-1R signaling. In this study, puerarin, a diet isoflavone, was evaluated its beneficial effects on β-cell survival and GLP-1R pathway. We showed that puerarin reduced the body weight gain, normalized blood glucose, and improved glucose tolerance in high-fat diet-induced and db/db diabetic mice. Most importantly, increased β-cell mass and β-cell proliferation but decreased β-cell apoptosis were observed in puerarin-treated diabetic mice as examined by immunostaining of mice pancreatic sections. The protective effect of puerarin on β-cell survival was confirmed in isolated mouse islets treated with high glucose. Further mechanism studies showed that the circulating level of GLP-1 in mice was unaffected by puerarin. However, puerarin enhanced GLP-1R signaling by up-regulating expressions of GLP-1R and pancreatic and duodenal homeobox 1, which subsequently led to protein kinase B (Akt) activation but forkhead box O1 inactivation, and promoted β-cell survival. The protective effect of puerarin was remarkably suppressed by Exendin(9-39), an antagonist of GLP-1R. Our study demonstrated puerarin improved glucose homeostasis in obese diabetic mice and identified a novel role of puerarin in protecting β-cell survival by mechanisms involving activation of GLP-1R signaling and downstream targets.","PeriodicalId":18812,"journal":{"name":"Molecular endocrinology","volume":"30 3 1","pages":"361-71"},"PeriodicalIF":0.0,"publicationDate":"2016-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1210/me.2015-1213","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66016313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ye Lin, Xiaoming Hou, W. Shen, R. Hanssen, V. Khor, Y. Cortez, A. Roseman, S. Azhar, F. Kraemer
Vesicular transport involving soluble N-ethylmaleimide sensitive factor attachment protein receptor (SNARE) proteins is known to be responsible for many major cellular activities. In steroidogenic tissues, chronic hormone stimulation results in increased expression of proteins involved in the steroidogenic pathway, whereas acute hormone stimulation prompts the rapid transfer of cholesterol to the inner mitochondrial membrane to be utilized as substrate for steroid hormone production. Several different pathways are involved in supplying cholesterol to mitochondria, but mobilization of stored cholesteryl esters appears to initially constitute the preferred source; however, the mechanisms mediating this cholesterol transfer are not fully understood. To study the potential contribution of SNARE proteins in steroidogenesis, we examined the expression levels of various SNARE proteins in response to hormone stimulation in steroidogenic tissues and cells and established an in vitro mitochondria reconstitution assay system to assess the contribution of various SNARE proteins on cholesterol delivery for steroidogenesis. Our results from reconstitution experiments along with knockdown studies in rat primary granulosa cells and in a Leydig cell line show that soluble N-ethylmaleimide sensitive factor attachment protein-α, synaptosomal-associated protein of 25 kDa, syntaxin-5, and syntaxin-17 facilitate the transport of cholesterol to mitochondria. Thus, although StAR is required for efficient cholesterol movement into mitochondria for steroidogenesis, specific SNAREs participate and are necessary to mediate cholesterol movement to mitochondria.
{"title":"SNARE-Mediated Cholesterol Movement to Mitochondria Supports Steroidogenesis in Rodent Cells.","authors":"Ye Lin, Xiaoming Hou, W. Shen, R. Hanssen, V. Khor, Y. Cortez, A. Roseman, S. Azhar, F. Kraemer","doi":"10.1210/me.2015-1281","DOIUrl":"https://doi.org/10.1210/me.2015-1281","url":null,"abstract":"Vesicular transport involving soluble N-ethylmaleimide sensitive factor attachment protein receptor (SNARE) proteins is known to be responsible for many major cellular activities. In steroidogenic tissues, chronic hormone stimulation results in increased expression of proteins involved in the steroidogenic pathway, whereas acute hormone stimulation prompts the rapid transfer of cholesterol to the inner mitochondrial membrane to be utilized as substrate for steroid hormone production. Several different pathways are involved in supplying cholesterol to mitochondria, but mobilization of stored cholesteryl esters appears to initially constitute the preferred source; however, the mechanisms mediating this cholesterol transfer are not fully understood. To study the potential contribution of SNARE proteins in steroidogenesis, we examined the expression levels of various SNARE proteins in response to hormone stimulation in steroidogenic tissues and cells and established an in vitro mitochondria reconstitution assay system to assess the contribution of various SNARE proteins on cholesterol delivery for steroidogenesis. Our results from reconstitution experiments along with knockdown studies in rat primary granulosa cells and in a Leydig cell line show that soluble N-ethylmaleimide sensitive factor attachment protein-α, synaptosomal-associated protein of 25 kDa, syntaxin-5, and syntaxin-17 facilitate the transport of cholesterol to mitochondria. Thus, although StAR is required for efficient cholesterol movement into mitochondria for steroidogenesis, specific SNAREs participate and are necessary to mediate cholesterol movement to mitochondria.","PeriodicalId":18812,"journal":{"name":"Molecular endocrinology","volume":"68 1","pages":"234-47"},"PeriodicalIF":0.0,"publicationDate":"2016-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1210/me.2015-1281","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66016235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Pauerstein, K. Park, H. Peiris, Jing Wang, Seung K. Kim
The 2 most abundant human pancreatic islet cell types are insulin-producing β-cells and glucagon-producing α-cells. Defined cis-regulatory elements from rodent Insulin genes have permitted genetic labeling of human islet β-cells, enabling lineage tracing and generation of human β-cell lines, but analogous elements for genetically labeling human α-cells with high specificity do not yet exist. To identify genetic elements that specifically direct reporter expression to human α-cells, we investigated noncoding sequences adjacent to the human GLUCAGON and ARX genes, which are expressed in islet α-cells. Elements with high evolutionary conservation were cloned into lentiviral vectors to direct fluorescent reporter expression in primary human islets. Based on the specificity of reporter expression for α- and β-cells, we found that rat glucagon promoter was not specific for human α-cells but that addition of human GLUCAGON untranslated region sequences substantially enhanced specificity of labeling in both cultured and transplanted islets to a degree not previously reported, to our knowledge. Specific transgene expression from these cis-regulatory sequences in human α-cells should enable targeted genetic modification and lineage tracing.
{"title":"Research Resource: Genetic Labeling of Human Islet Alpha Cells.","authors":"P. Pauerstein, K. Park, H. Peiris, Jing Wang, Seung K. Kim","doi":"10.1210/me.2015-1220","DOIUrl":"https://doi.org/10.1210/me.2015-1220","url":null,"abstract":"The 2 most abundant human pancreatic islet cell types are insulin-producing β-cells and glucagon-producing α-cells. Defined cis-regulatory elements from rodent Insulin genes have permitted genetic labeling of human islet β-cells, enabling lineage tracing and generation of human β-cell lines, but analogous elements for genetically labeling human α-cells with high specificity do not yet exist. To identify genetic elements that specifically direct reporter expression to human α-cells, we investigated noncoding sequences adjacent to the human GLUCAGON and ARX genes, which are expressed in islet α-cells. Elements with high evolutionary conservation were cloned into lentiviral vectors to direct fluorescent reporter expression in primary human islets. Based on the specificity of reporter expression for α- and β-cells, we found that rat glucagon promoter was not specific for human α-cells but that addition of human GLUCAGON untranslated region sequences substantially enhanced specificity of labeling in both cultured and transplanted islets to a degree not previously reported, to our knowledge. Specific transgene expression from these cis-regulatory sequences in human α-cells should enable targeted genetic modification and lineage tracing.","PeriodicalId":18812,"journal":{"name":"Molecular endocrinology","volume":"30 2 1","pages":"248-53"},"PeriodicalIF":0.0,"publicationDate":"2016-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1210/me.2015-1220","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66016414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Matthew J. Fuxjager, Jae-Hyung Lee, Tak-Ming Chan, J. Bahn, Jenifer G. Chew, X. Xiao, B. Schlinger
Male vertebrate social displays vary from physically simple to complex, with the latter involving exquisite motor command of the body and appendages. Studies of these displays have, in turn, provided substantial insight into neuromotor mechanisms. The neotropical golden-collared manakin (Manacus vitellinus) has been used previously as a model to investigate intricate motor skills because adult males of this species perform an acrobatic and androgen-dependent courtship display. To support this behavior, these birds express elevated levels of androgen receptors (AR) in their skeletal muscles. Here we use RNA sequencing to explore how testosterone (T) modulates the muscular transcriptome to support male manakin courtship displays. In addition, we explore how androgens influence gene expression in the muscles of the zebra finch (Taenopygia guttata), a model passerine bird with a limited courtship display and minimal muscle AR. We identify androgen-dependent, muscle-specific gene regulation in both species. In addition, we identify manakin-specific effects that are linked to muscle use during the manakin display, including androgenic regulation of genes associated with muscle fiber contractility, cellular homeostasis, and energetic efficiency. Overall, our results point to numerous genes and gene networks impacted by androgens in male birds, including some that underlie optimal muscle function necessary for performing acrobatic display routines. Manakins are excellent models to explore gene regulation promoting athletic ability.
{"title":"Research Resource: Hormones, Genes, and Athleticism: Effect of Androgens on the Avian Muscular Transcriptome.","authors":"Matthew J. Fuxjager, Jae-Hyung Lee, Tak-Ming Chan, J. Bahn, Jenifer G. Chew, X. Xiao, B. Schlinger","doi":"10.1210/me.2015-1270","DOIUrl":"https://doi.org/10.1210/me.2015-1270","url":null,"abstract":"Male vertebrate social displays vary from physically simple to complex, with the latter involving exquisite motor command of the body and appendages. Studies of these displays have, in turn, provided substantial insight into neuromotor mechanisms. The neotropical golden-collared manakin (Manacus vitellinus) has been used previously as a model to investigate intricate motor skills because adult males of this species perform an acrobatic and androgen-dependent courtship display. To support this behavior, these birds express elevated levels of androgen receptors (AR) in their skeletal muscles. Here we use RNA sequencing to explore how testosterone (T) modulates the muscular transcriptome to support male manakin courtship displays. In addition, we explore how androgens influence gene expression in the muscles of the zebra finch (Taenopygia guttata), a model passerine bird with a limited courtship display and minimal muscle AR. We identify androgen-dependent, muscle-specific gene regulation in both species. In addition, we identify manakin-specific effects that are linked to muscle use during the manakin display, including androgenic regulation of genes associated with muscle fiber contractility, cellular homeostasis, and energetic efficiency. Overall, our results point to numerous genes and gene networks impacted by androgens in male birds, including some that underlie optimal muscle function necessary for performing acrobatic display routines. Manakins are excellent models to explore gene regulation promoting athletic ability.","PeriodicalId":18812,"journal":{"name":"Molecular endocrinology","volume":"30 2 1","pages":"254-71"},"PeriodicalIF":0.0,"publicationDate":"2016-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1210/me.2015-1270","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66016145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alice K Treen, V. Luo, J. Chalmers, P. Dalvi, D. Tran, Wenqing Ye, G. Kim, Z. Friedman, D. Belsham
Kisspeptin (Kiss) and G-protein-coupled receptor (Gpr)54 have emerged as key regulators of reproduction. 17β-estradiol (E2)-mediated regulation of these neurons is nuclei specific, where anteroventral periventricular (AVPV) Kiss neurons are positively regulated by E2, whereas arcuate nucleus (ARC) neurons are inhibited. We have generated immortalized Kiss cell lines from male and female adult-derived murine hypothalamic primary culture, as well as cell lines from microdissected AVPV and ARC from female Kiss-green fluorescent protein (GFP) mice. All exhibit endogenous Kiss-1 expression, estrogen receptors (ER)s (ERα, ERβ, and Gpr30), as well as known markers of AVPV Kiss neurons in the mHypoA-50 and mHypoA-Kiss/GFP-4, vs markers of ARC Kiss neurons in the mHypoA-55 and the mHypoA-Kiss/GFP-3 lines. There was an increase in Kiss-1 mRNA expression at 24 hours in the AVPV lines and a repression of Kiss-1 mRNA at 4 hours in the ARC lines. An E2-mediated decrease in ERα mRNA expression at 24 hours in the AVPV cell lines was detected, and a significant decrease in Gpr30, ERα, and ERβ mRNA levels at 4 hours in the ARC cell lines was evident. ER agonists and antagonists determined the specific ERs responsible for mediating changes in gene expression. In the AVPV, ERα is required but not ERβ or GPR30, vs the ARC Kiss-expressing cell lines that require GPR30, and either ERα and/or ERβ. We determined cAMP response element-binding protein 1 was necessary for the down-regulation of Kiss-1 mRNA expression using small interfering RNA knockdown in the ARC cell model. These studies elucidate some of the molecular events involved in the differential E2-mediated regulation of unique and specific Kiss neuronal models.
{"title":"Divergent Regulation of ER and Kiss Genes by 17β-Estradiol in Hypothalamic ARC Versus AVPV Models.","authors":"Alice K Treen, V. Luo, J. Chalmers, P. Dalvi, D. Tran, Wenqing Ye, G. Kim, Z. Friedman, D. Belsham","doi":"10.1210/me.2015-1189","DOIUrl":"https://doi.org/10.1210/me.2015-1189","url":null,"abstract":"Kisspeptin (Kiss) and G-protein-coupled receptor (Gpr)54 have emerged as key regulators of reproduction. 17β-estradiol (E2)-mediated regulation of these neurons is nuclei specific, where anteroventral periventricular (AVPV) Kiss neurons are positively regulated by E2, whereas arcuate nucleus (ARC) neurons are inhibited. We have generated immortalized Kiss cell lines from male and female adult-derived murine hypothalamic primary culture, as well as cell lines from microdissected AVPV and ARC from female Kiss-green fluorescent protein (GFP) mice. All exhibit endogenous Kiss-1 expression, estrogen receptors (ER)s (ERα, ERβ, and Gpr30), as well as known markers of AVPV Kiss neurons in the mHypoA-50 and mHypoA-Kiss/GFP-4, vs markers of ARC Kiss neurons in the mHypoA-55 and the mHypoA-Kiss/GFP-3 lines. There was an increase in Kiss-1 mRNA expression at 24 hours in the AVPV lines and a repression of Kiss-1 mRNA at 4 hours in the ARC lines. An E2-mediated decrease in ERα mRNA expression at 24 hours in the AVPV cell lines was detected, and a significant decrease in Gpr30, ERα, and ERβ mRNA levels at 4 hours in the ARC cell lines was evident. ER agonists and antagonists determined the specific ERs responsible for mediating changes in gene expression. In the AVPV, ERα is required but not ERβ or GPR30, vs the ARC Kiss-expressing cell lines that require GPR30, and either ERα and/or ERβ. We determined cAMP response element-binding protein 1 was necessary for the down-regulation of Kiss-1 mRNA expression using small interfering RNA knockdown in the ARC cell model. These studies elucidate some of the molecular events involved in the differential E2-mediated regulation of unique and specific Kiss neuronal models.","PeriodicalId":18812,"journal":{"name":"Molecular endocrinology","volume":"30 2 1","pages":"217-33"},"PeriodicalIF":0.0,"publicationDate":"2016-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1210/me.2015-1189","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66016172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Makiko Fukaya, C. Brorsson, Kira Meyerovich, L. Catrysse, Diane Delaroche, E. Vanzela, F. Ortis, R. Beyaert, L. Nielsen, M. L. Andersen, H. Mortensen, F. Pociot, G. van Loo, J. Størling, A. K. Cardozo
Activation of the transcription factor nuclear factor kappa B (NFkB) contributes to β-cell death in type 1 diabetes (T1D). Genome-wide association studies have identified the gene TNF-induced protein 3 (TNFAIP3), encoding for the zinc finger protein A20, as a susceptibility locus for T1D. A20 restricts NF-κB signaling and has strong antiapoptotic activities in β-cells. Although the role of A20 on NF-κB inhibition is well characterized, its other antiapoptotic functions are largely unknown. By studying INS-1E cells and rat dispersed islet cells knocked down or overexpressing A20 and islets isolated from the β-cell-specific A20 knockout mice, we presently demonstrate that A20 has broader effects in β-cells that are not restricted to inhibition of NF-κB. These involves, suppression of the proapoptotic mitogen-activated protein kinase c-Jun N-terminal kinase (JNK), activation of survival signaling via v-akt murine thymoma viral oncogene homolog (Akt) and consequently inhibition of the intrinsic apoptotic pathway. Finally, in a cohort of T1D children, we observed that the risk allele of the rs2327832 single nucleotide polymorphism of TNFAIP3 predicted lower C-peptide and higher hemoglobin A1c (HbA1c) levels 12 months after disease onset, indicating reduced residual β-cell function and impaired glycemic control. In conclusion, our results indicate a critical role for A20 in the regulation of β-cell survival and unveil novel mechanisms by which A20 controls β-cell fate. Moreover, we identify the single nucleotide polymorphism rs2327832 of TNFAIP3 as a possible prognostic marker for diabetes outcome in children with T1D.
转录因子核因子κ B (NFkB)的激活有助于1型糖尿病(T1D)的β细胞死亡。全基因组关联研究发现，编码锌指蛋白A20的tnf诱导蛋白3 (TNFAIP3)基因是T1D的易感位点。A20抑制NF-κB信号传导，在β-细胞中具有较强的抗凋亡活性。虽然A20在NF-κB抑制中的作用已被明确，但其其他抗凋亡功能在很大程度上尚不清楚。通过研究敲除或过表达A20的INS-1E细胞和大鼠分散胰岛细胞，以及从β细胞特异性敲除A20的小鼠中分离的胰岛细胞，我们目前证明A20在β细胞中具有更广泛的作用，不仅限于抑制NF-κB。这些包括抑制促凋亡丝裂原激活的蛋白激酶c-Jun n-末端激酶(JNK)，通过v-akt小鼠胸腺瘤病毒癌基因同源物(Akt)激活存活信号，从而抑制内在凋亡途径。最后，在一组T1D儿童中，我们观察到TNFAIP3 rs2327832单核苷酸多态性的风险等位基因预测疾病发病12个月后c肽降低和血红蛋白A1c (HbA1c)水平升高，表明残余β细胞功能降低和血糖控制受损。总之，我们的研究结果表明A20在调节β细胞存活中起着关键作用，并揭示了A20控制β细胞命运的新机制。此外，我们发现TNFAIP3的单核苷酸多态性rs2327832可能是T1D儿童糖尿病结局的预后标志物。
{"title":"A20 Inhibits β-Cell Apoptosis by Multiple Mechanisms and Predicts Residual β-Cell Function in Type 1 Diabetes.","authors":"Makiko Fukaya, C. Brorsson, Kira Meyerovich, L. Catrysse, Diane Delaroche, E. Vanzela, F. Ortis, R. Beyaert, L. Nielsen, M. L. Andersen, H. Mortensen, F. Pociot, G. van Loo, J. Størling, A. K. Cardozo","doi":"10.1210/me.2015-1176","DOIUrl":"https://doi.org/10.1210/me.2015-1176","url":null,"abstract":"Activation of the transcription factor nuclear factor kappa B (NFkB) contributes to β-cell death in type 1 diabetes (T1D). Genome-wide association studies have identified the gene TNF-induced protein 3 (TNFAIP3), encoding for the zinc finger protein A20, as a susceptibility locus for T1D. A20 restricts NF-κB signaling and has strong antiapoptotic activities in β-cells. Although the role of A20 on NF-κB inhibition is well characterized, its other antiapoptotic functions are largely unknown. By studying INS-1E cells and rat dispersed islet cells knocked down or overexpressing A20 and islets isolated from the β-cell-specific A20 knockout mice, we presently demonstrate that A20 has broader effects in β-cells that are not restricted to inhibition of NF-κB. These involves, suppression of the proapoptotic mitogen-activated protein kinase c-Jun N-terminal kinase (JNK), activation of survival signaling via v-akt murine thymoma viral oncogene homolog (Akt) and consequently inhibition of the intrinsic apoptotic pathway. Finally, in a cohort of T1D children, we observed that the risk allele of the rs2327832 single nucleotide polymorphism of TNFAIP3 predicted lower C-peptide and higher hemoglobin A1c (HbA1c) levels 12 months after disease onset, indicating reduced residual β-cell function and impaired glycemic control. In conclusion, our results indicate a critical role for A20 in the regulation of β-cell survival and unveil novel mechanisms by which A20 controls β-cell fate. Moreover, we identify the single nucleotide polymorphism rs2327832 of TNFAIP3 as a possible prognostic marker for diabetes outcome in children with T1D.","PeriodicalId":18812,"journal":{"name":"Molecular endocrinology","volume":"46 1","pages":"48-61"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1210/me.2015-1176","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66016105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-01-01DOI: 10.1210/mend.2016.30.issue-8.toc
intellipap de DeVilbiss
{"title":"Table of Contents.","authors":"intellipap de DeVilbiss","doi":"10.1210/mend.2016.30.issue-8.toc","DOIUrl":"https://doi.org/10.1210/mend.2016.30.issue-8.toc","url":null,"abstract":"","PeriodicalId":18812,"journal":{"name":"Molecular endocrinology","volume":"30 8 1","pages":"5A-6A"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66020922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-01-01DOI: 10.1210/mend.2016.30.issue-2.toc
J. Huseynov, Committee Chair
The dissertation of Javid J. Huseynov is approved and is acceptable in quality and form for publication on microfilm and in digital formats: ii DEDICATION To my mother and to all others that are dear to me...
Javid J. Huseynov的论文在质量和形式上被批准，可以在缩微胶卷和数字格式上发表:ii献给我的母亲和所有对我来说亲爱的其他人……
{"title":"Table of Contents.","authors":"J. Huseynov, Committee Chair","doi":"10.1210/mend.2016.30.issue-2.toc","DOIUrl":"https://doi.org/10.1210/mend.2016.30.issue-2.toc","url":null,"abstract":"The dissertation of Javid J. Huseynov is approved and is acceptable in quality and form for publication on microfilm and in digital formats: ii DEDICATION To my mother and to all others that are dear to me...","PeriodicalId":18812,"journal":{"name":"Molecular endocrinology","volume":"30 2 1","pages":"4A-5A"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66020558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jing Li, Jun Song, H. Weiss, Todd Weiss, C. Townsend, B. Evers
AMP-activated protein kinase (AMPK), a critical fuel-sensing enzyme, regulates the metabolic effects of various hormones. Neurotensin (NT) is a 13-amino acid peptide predominantly localized in enteroendocrine cells of the small bowel and released by fat ingestion. Increased fasting plasma levels of pro-NT (a stable NT precursor fragment produced in equimolar amounts relative to NT) are associated with an increased risk of diabetes, cardiovascular disease, and mortality; however, the mechanisms regulating NT release are not fully defined. We previously reported that inhibition of the mammalian target of rapamycin (mTOR) complex 1 (mTORC1) increases NT secretion and gene expression through activation of the MEK/ERK pathway. Here, we show that activation of AMPK increases NT secretion from endocrine cell lines (BON and QGP-1) and isolated mouse crypt cells enriched for NT-positive cells. In addition, plasma levels of NT increase in mice treated with 5-aminoimidazole-4-carboxamide riboside, a pharmacologic AMPK activator. Small interfering RNA-mediated knockdown of AMPKα decrease, whereas overexpression of the subunit significantly enhances, NT secretion from BON cells treated with AMPK activators or oleic acid. Similarly, small interfering RNA knockdown of the upstream AMPK kinases, liver kinase B1 and Ca(2+) calmodulin-dependent protein kinase kinase 2, also attenuate NT release and AMPK phosphorylation. Moreover, AMPK activation increases NT secretion through inhibition of mTORC1 signaling. Together, our findings show that AMPK activation enhances NT release through inhibition of mTORC1 signaling, thus demonstrating an important cross talk regulation for NT secretion.
{"title":"Activation of AMPK Stimulates Neurotensin Secretion in Neuroendocrine Cells.","authors":"Jing Li, Jun Song, H. Weiss, Todd Weiss, C. Townsend, B. Evers","doi":"10.1210/me.2015-1094","DOIUrl":"https://doi.org/10.1210/me.2015-1094","url":null,"abstract":"AMP-activated protein kinase (AMPK), a critical fuel-sensing enzyme, regulates the metabolic effects of various hormones. Neurotensin (NT) is a 13-amino acid peptide predominantly localized in enteroendocrine cells of the small bowel and released by fat ingestion. Increased fasting plasma levels of pro-NT (a stable NT precursor fragment produced in equimolar amounts relative to NT) are associated with an increased risk of diabetes, cardiovascular disease, and mortality; however, the mechanisms regulating NT release are not fully defined. We previously reported that inhibition of the mammalian target of rapamycin (mTOR) complex 1 (mTORC1) increases NT secretion and gene expression through activation of the MEK/ERK pathway. Here, we show that activation of AMPK increases NT secretion from endocrine cell lines (BON and QGP-1) and isolated mouse crypt cells enriched for NT-positive cells. In addition, plasma levels of NT increase in mice treated with 5-aminoimidazole-4-carboxamide riboside, a pharmacologic AMPK activator. Small interfering RNA-mediated knockdown of AMPKα decrease, whereas overexpression of the subunit significantly enhances, NT secretion from BON cells treated with AMPK activators or oleic acid. Similarly, small interfering RNA knockdown of the upstream AMPK kinases, liver kinase B1 and Ca(2+) calmodulin-dependent protein kinase kinase 2, also attenuate NT release and AMPK phosphorylation. Moreover, AMPK activation increases NT secretion through inhibition of mTORC1 signaling. Together, our findings show that AMPK activation enhances NT release through inhibition of mTORC1 signaling, thus demonstrating an important cross talk regulation for NT secretion.","PeriodicalId":18812,"journal":{"name":"Molecular endocrinology","volume":"30 1 1","pages":"26-36"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1210/me.2015-1094","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66015867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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