Type 2 diabetes is one of the most prevalent and serious metabolic diseases.Under diabetic conditions,chronic hyperglycemia and subsequent induction of oxidative stress deteriorate pancreaticβ-cell function,which lea...Type 2 diabetes is one of the most prevalent and serious metabolic diseases.Under diabetic conditions,chronic hyperglycemia and subsequent induction of oxidative stress deteriorate pancreaticβ-cell function,which leads to the aggravation of type 2 diabetes.Although such phenomena are well known as glucose toxicity,its molecular mechanism remains unclear.In this review article,we describe the possible molecular mechanism forβ-cell dysfunction found in type 2 diabetes,focusing on(1)oxidative stress,(2)pancreatic transcription factors(PDX-1 and MafA)and(3)incretin receptors(GLP-1 and GIP receptors).Under such conditions,nuclear expression levels of PDX-1 and MafA are decreased,which leads to suppression of insulin biosynthesis and secretion.In addition,expression levels of GLP-1 and GIP receptors are decreased,which likely contributes to the impaired incretin effects found in diabetes.Taken together,it is likely that downregulation of pancreatic transcription factors(PDX-1and MafA)and down-regulation of incretin receptors(GLP-1 and GIP receptors)explain,at least in part,the molecular mechanism forβ-cell dysfunction found in type 2 diabetes.展开更多
AIM： To examine the effects of adiponectin on the functions of Kupffer cells, key modulators of lipopolysaccharide （LPS） -induced liver injury.METHODS： D-galactosamine （GAIN） and LPS were injected intraperitonea...AIM： To examine the effects of adiponectin on the functions of Kupffer cells, key modulators of lipopolysaccharide （LPS） -induced liver injury.METHODS： D-galactosamine （GAIN） and LPS were injected intraperitoneally into adiponectin-/- mice and wild type mice. Kupffer cells, isolated from Sprague-Dawley rats, were preincubated with or without adiponectin, and then treated with LPS.RESULTS： In knockout mice, GalN/LPS injection significantly lowered the survival rate, significantly raised the plasma levels of alanine transaminase and tumor necrosis factor-α （TNF-α） and significantly reduced IL-10 levels compared with wild type mice. TNF-α gene expression in the liver was which higher and those of IL-10 were lower in knockout mice than in wild type mice. In cultured adiponectin-pre-treated Kupffer cells, LPS significantly lowered TNF-α levels and raised IL-10 levels in the culture media and their respective gene expression levels, compared with Kupffer cells without adiponectinpre-treatment.CONCLUSION： Adiponectin supresses TNF-α production and induces IL-10 production by Kupffer cells in response to LPS stimulation, and a lack of adiponectin enhances LPS-induced liver injury.展开更多
文摘Type 2 diabetes is one of the most prevalent and serious metabolic diseases.Under diabetic conditions,chronic hyperglycemia and subsequent induction of oxidative stress deteriorate pancreaticβ-cell function,which leads to the aggravation of type 2 diabetes.Although such phenomena are well known as glucose toxicity,its molecular mechanism remains unclear.In this review article,we describe the possible molecular mechanism forβ-cell dysfunction found in type 2 diabetes,focusing on(1)oxidative stress,(2)pancreatic transcription factors(PDX-1 and MafA)and(3)incretin receptors(GLP-1 and GIP receptors).Under such conditions,nuclear expression levels of PDX-1 and MafA are decreased,which leads to suppression of insulin biosynthesis and secretion.In addition,expression levels of GLP-1 and GIP receptors are decreased,which likely contributes to the impaired incretin effects found in diabetes.Taken together,it is likely that downregulation of pancreatic transcription factors(PDX-1and MafA)and down-regulation of incretin receptors(GLP-1 and GIP receptors)explain,at least in part,the molecular mechanism forβ-cell dysfunction found in type 2 diabetes.
文摘AIM： To examine the effects of adiponectin on the functions of Kupffer cells, key modulators of lipopolysaccharide （LPS） -induced liver injury.METHODS： D-galactosamine （GAIN） and LPS were injected intraperitoneally into adiponectin-/- mice and wild type mice. Kupffer cells, isolated from Sprague-Dawley rats, were preincubated with or without adiponectin, and then treated with LPS.RESULTS： In knockout mice, GalN/LPS injection significantly lowered the survival rate, significantly raised the plasma levels of alanine transaminase and tumor necrosis factor-α （TNF-α） and significantly reduced IL-10 levels compared with wild type mice. TNF-α gene expression in the liver was which higher and those of IL-10 were lower in knockout mice than in wild type mice. In cultured adiponectin-pre-treated Kupffer cells, LPS significantly lowered TNF-α levels and raised IL-10 levels in the culture media and their respective gene expression levels, compared with Kupffer cells without adiponectinpre-treatment.CONCLUSION： Adiponectin supresses TNF-α production and induces IL-10 production by Kupffer cells in response to LPS stimulation, and a lack of adiponectin enhances LPS-induced liver injury.
