Type 2 diabetes一associated with impaired insulin/insulin-like growth factor-1 (IGF1) signaling (IIS)一is a risk factor for cognitive impairment and dementia including Alzheimer's disease (AD). The insulin recepto...Type 2 diabetes一associated with impaired insulin/insulin-like growth factor-1 (IGF1) signaling (IIS)一is a risk factor for cognitive impairment and dementia including Alzheimer's disease (AD). The insulin receptor substrate (IRS) proteins are major components of IIS, which transmit upstream signals via the insulin receptor and/or IGF1 receptor to multiple intracellular signaling pathways, including AKT/protein kinase B and extracellular-signal-regulated kinase cascades. Of the four IRS proteins in mammals, IRS1 and IRS2 play key roles in regulating growth and survival, metabolism, and aging. Meanwhile, the roles of IRS1 and IRS2 in the central nervous system with respect to cognitive abilities remain to be clarified. In contrast to IRS2 in peripheral tissues, inactivation of neural IRS2 exerts beneficial effects, resulting in the reduction of amyloid p accumulation and premature mortality in AD mouse models. On the other hand, the increased phosphorylation of IRS 1 at several serine sites is observed in the brains from patients with AD and animal models of AD or cognitive impairment induced by type 2 diabetes. However, these serine sites are also activated in a mouse model of type 2 diabetes, in which the diabetes drug metformin improves memory impairment. Because IRS1 and IRS2 signaling pathways are regulated through complex mechanisms including positive and negative feedback loops, whether the elevated phosphorylation of IRS1 at specific serine sites found in AD brains is a primary response to cognitive dysfunction remains unknown. Here, we examine the associations between IRS 1 /1 RS2-mediated signaling in the central nervous system and cognitive decline.展开更多
Objective: To investigate the influence of nutrients on the expression of insulin receptor and its related substrate genes in the mice muscle.Methods: C57BL/6J mice were randomly divided into 4 groups: ①HF, mice on h...Objective: To investigate the influence of nutrients on the expression of insulin receptor and its related substrate genes in the mice muscle.Methods: C57BL/6J mice were randomly divided into 4 groups: ①HF, mice on high fat diet; ② G + F, supplemented with glutamine after 3 months on high fat diet; ③Gln, high fat with glutamine;④Control,normal diet. Each group has been on the diet for 5.5 months. RT-PCR was used to determine the mRNA levels of insulin receptor (IR), insulin receptor substrate-1(IRS-1), insulin receptor substrate-2(IRS-2) and phosphatidylinositol 3-kinase(PI-3-ki- nase). Results: The results showed that the mRNA levels of IR, IRS-1, IRS-2 and PI-3 kinase of the mice on high fat diet were lowered to some degree, they were 81%,63%,59% and 45% of that of control respectively. Cnoclusion: Glutamine can prevent reduction of the mRNA level with the above-mentioned genes in fat group. The results suggest that nutrients may influence insulin sensitivity through regulation of gene expression.展开更多
AIM: To investigate the effects of blockade of insulin receptor substrate-1(IRS-1) on the bio-function of tube formation of human choroidal endothelial cells(HCECs).METHODS: Quantitative reverse transcriptionpolymeras...AIM: To investigate the effects of blockade of insulin receptor substrate-1(IRS-1) on the bio-function of tube formation of human choroidal endothelial cells(HCECs).METHODS: Quantitative reverse transcriptionpolymerase chain reaction(RT-PCR) and Western blot were performed to determine the expression level of IRS-1 and phospho-IRS-1 in HCECs. Tube formation of HCECs was analyzed using three dimensional in vitro Matrigel assay with or without IRS-1 blockage via IRS-1 inhibitor(GS-101) and vascular endothelial growth factor receptor 2(VEGFR2) inhibitor. In addition, cell counting kit(CCK)-8 and Transwell migration assay were exerted to analyze the effects of blockade of IRS-1 on the bio-function of proliferation and migration of HCECs, respectively. The apoptosis of HCECs was examined using flow cytometry(FCM).RESULTS: RT-PCR and Western blot revealed that IRS-1 phospho-IRS-1 were expressed in HCECs and the expression level was enhanced by stimulation of VEGF-A. The number of tube formation was decreased significantly in GS-101 treated groups compared to phosphate buffered saline(PBS) treated control groups. Furthermore, both cell proliferation and migration of HCECs were decreased in the presence of GS-101. FCM analysis showed that the apoptosis of HCECs was enhanced when the cells were treated with GS-101. Western blot also showed that the expression level of cleaved-caspase 3 in GS-101 treated group was higher than that in control group.CONCLUSION: Blockade of IRS-1 can inhibit tube formation of HCECs through reducing cell proliferation and migration and promoting cell apoptosis.展开更多
Aim: Metabolic syndrome (MetS) is a major risk factor for both diabetes mellitus and cardiovascular disease (CVD). The aims of the study were 1) to investigate the insulin receptor substrate-1 (IRS-1) and insulin rece...Aim: Metabolic syndrome (MetS) is a major risk factor for both diabetes mellitus and cardiovascular disease (CVD). The aims of the study were 1) to investigate the insulin receptor substrate-1 (IRS-1) and insulin receptor substrate-2 (IRS-2) gene polymorphisms in patients with MetS and 2) to examine the relationships between gene polymorphisms and components of MetS. Patients & Methods: The study population included 100 patients with MetS and 30 patients without MetS as control group. Metabolic syndrome (MS) was defined as in ATP III. Entire coding exons of IRS-1 and IRS-2 genes were amplified by polymerase chain reaction (PCR). Insulin resistance (IR) was estimated using the homeostasis model assessment (HOMA). Results: In patients with MetS, 34 (34%), had G972R (rs1801278) gene polymorphism and 66 (66%) had no nucleotide substitutions at the IRS-1 gene (p circumference, blood pressure, triglyceride, HDL-Cholesterol, LDL-Cholesterol and HOMA-IR levels. Conclusion: Insulin receptor substrate-1 and 2 gene polymorphisms were associated with metabolic syndrome but not its components.展开更多
基金supported by a MEXTGrant-in-Aid for Scientific Research on Innovative Areas(brain environment)(JP24111536 to AT)+3 种基金JSPS KAKENHI(JP24650201,JP26282026,JP17K19951,JP17H02188 to AT)grants from the Mitsubishi Foundation(to AT)NOVARTIS Foundation Japan for the Promotion of Science(to AT)
文摘Type 2 diabetes一associated with impaired insulin/insulin-like growth factor-1 (IGF1) signaling (IIS)一is a risk factor for cognitive impairment and dementia including Alzheimer's disease (AD). The insulin receptor substrate (IRS) proteins are major components of IIS, which transmit upstream signals via the insulin receptor and/or IGF1 receptor to multiple intracellular signaling pathways, including AKT/protein kinase B and extracellular-signal-regulated kinase cascades. Of the four IRS proteins in mammals, IRS1 and IRS2 play key roles in regulating growth and survival, metabolism, and aging. Meanwhile, the roles of IRS1 and IRS2 in the central nervous system with respect to cognitive abilities remain to be clarified. In contrast to IRS2 in peripheral tissues, inactivation of neural IRS2 exerts beneficial effects, resulting in the reduction of amyloid p accumulation and premature mortality in AD mouse models. On the other hand, the increased phosphorylation of IRS 1 at several serine sites is observed in the brains from patients with AD and animal models of AD or cognitive impairment induced by type 2 diabetes. However, these serine sites are also activated in a mouse model of type 2 diabetes, in which the diabetes drug metformin improves memory impairment. Because IRS1 and IRS2 signaling pathways are regulated through complex mechanisms including positive and negative feedback loops, whether the elevated phosphorylation of IRS1 at specific serine sites found in AD brains is a primary response to cognitive dysfunction remains unknown. Here, we examine the associations between IRS 1 /1 RS2-mediated signaling in the central nervous system and cognitive decline.
文摘Objective: To investigate the influence of nutrients on the expression of insulin receptor and its related substrate genes in the mice muscle.Methods: C57BL/6J mice were randomly divided into 4 groups: ①HF, mice on high fat diet; ② G + F, supplemented with glutamine after 3 months on high fat diet; ③Gln, high fat with glutamine;④Control,normal diet. Each group has been on the diet for 5.5 months. RT-PCR was used to determine the mRNA levels of insulin receptor (IR), insulin receptor substrate-1(IRS-1), insulin receptor substrate-2(IRS-2) and phosphatidylinositol 3-kinase(PI-3-ki- nase). Results: The results showed that the mRNA levels of IR, IRS-1, IRS-2 and PI-3 kinase of the mice on high fat diet were lowered to some degree, they were 81%,63%,59% and 45% of that of control respectively. Cnoclusion: Glutamine can prevent reduction of the mRNA level with the above-mentioned genes in fat group. The results suggest that nutrients may influence insulin sensitivity through regulation of gene expression.
基金Supported by the National Natural Science Foundation in China(No.81671641 No.81970830+6 种基金 No.31600736)Suzhou Municipal Natural Science Foundation(No.SYS201745)Soochow University Doctoral Academic Talents Program(No.5832001313)Jiangsu Provincial Medical Youth Talent(No.QNRC2016718)Jiangsu Provincial Medical Innovation Team(No.CXTDA2017039)Jiangsu Provincial Natural Science Foundation(No.BK20151208)the Soochow Scholar Project of Soochow University(No.R5122001)
文摘AIM: To investigate the effects of blockade of insulin receptor substrate-1(IRS-1) on the bio-function of tube formation of human choroidal endothelial cells(HCECs).METHODS: Quantitative reverse transcriptionpolymerase chain reaction(RT-PCR) and Western blot were performed to determine the expression level of IRS-1 and phospho-IRS-1 in HCECs. Tube formation of HCECs was analyzed using three dimensional in vitro Matrigel assay with or without IRS-1 blockage via IRS-1 inhibitor(GS-101) and vascular endothelial growth factor receptor 2(VEGFR2) inhibitor. In addition, cell counting kit(CCK)-8 and Transwell migration assay were exerted to analyze the effects of blockade of IRS-1 on the bio-function of proliferation and migration of HCECs, respectively. The apoptosis of HCECs was examined using flow cytometry(FCM).RESULTS: RT-PCR and Western blot revealed that IRS-1 phospho-IRS-1 were expressed in HCECs and the expression level was enhanced by stimulation of VEGF-A. The number of tube formation was decreased significantly in GS-101 treated groups compared to phosphate buffered saline(PBS) treated control groups. Furthermore, both cell proliferation and migration of HCECs were decreased in the presence of GS-101. FCM analysis showed that the apoptosis of HCECs was enhanced when the cells were treated with GS-101. Western blot also showed that the expression level of cleaved-caspase 3 in GS-101 treated group was higher than that in control group.CONCLUSION: Blockade of IRS-1 can inhibit tube formation of HCECs through reducing cell proliferation and migration and promoting cell apoptosis.
文摘Aim: Metabolic syndrome (MetS) is a major risk factor for both diabetes mellitus and cardiovascular disease (CVD). The aims of the study were 1) to investigate the insulin receptor substrate-1 (IRS-1) and insulin receptor substrate-2 (IRS-2) gene polymorphisms in patients with MetS and 2) to examine the relationships between gene polymorphisms and components of MetS. Patients & Methods: The study population included 100 patients with MetS and 30 patients without MetS as control group. Metabolic syndrome (MS) was defined as in ATP III. Entire coding exons of IRS-1 and IRS-2 genes were amplified by polymerase chain reaction (PCR). Insulin resistance (IR) was estimated using the homeostasis model assessment (HOMA). Results: In patients with MetS, 34 (34%), had G972R (rs1801278) gene polymorphism and 66 (66%) had no nucleotide substitutions at the IRS-1 gene (p circumference, blood pressure, triglyceride, HDL-Cholesterol, LDL-Cholesterol and HOMA-IR levels. Conclusion: Insulin receptor substrate-1 and 2 gene polymorphisms were associated with metabolic syndrome but not its components.
