As a pathological hallmark of type 2 diabetes mellitus(T2DM),islet amyloid is formed by the aggregation of islet amyloid polypeptide(IAPP).Endoplasmic reticulum(ER)stress interacts with IAPP aggregates and has been im...As a pathological hallmark of type 2 diabetes mellitus(T2DM),islet amyloid is formed by the aggregation of islet amyloid polypeptide(IAPP).Endoplasmic reticulum(ER)stress interacts with IAPP aggregates and has been implicated in the pathogenesis of T2DM.To examine the role of ER stress in T2DM,we cloned the hIAPP promoter and analyzed its promoter activity in human b-cells.We found that ER stress significantly enhanced hIAPP promoter activity and expression in human b-cells via triggering X-box binding protein 1(XBP1)splicing.We identified a binding site of XBP1 in the hIAPP promoter.Disruption of this binding site by substitution or deletion mutagenesis significantly diminished the effects of ER stress on hIAPP promoter activity.Blockade of XBP splicing by MKC3946 treatment inhibited ER stress-induced hIAPP up-regulation and improved human b-cell survival and function.Our study uncovers a link between ER stress and IAPP at the transcriptional level and may provide novel insights into the role of ER stress in IAPP cytotoxicity and the pathogenesis of T2DM.展开更多
基金This work was supported by the National Natural Science Foundation of China(No.82201576)Beijing Hospitals Authority Youth Programme(China)(No.QML20210804)+2 种基金Beijing Medical Research 2021-8Key Laboratory of Alzheimer's Disease of Zhejiang Province of China(No.ZJAD-2021004 to YZ)the National Natural Science Foundation of China(No.82230043 to WS).
文摘As a pathological hallmark of type 2 diabetes mellitus(T2DM),islet amyloid is formed by the aggregation of islet amyloid polypeptide(IAPP).Endoplasmic reticulum(ER)stress interacts with IAPP aggregates and has been implicated in the pathogenesis of T2DM.To examine the role of ER stress in T2DM,we cloned the hIAPP promoter and analyzed its promoter activity in human b-cells.We found that ER stress significantly enhanced hIAPP promoter activity and expression in human b-cells via triggering X-box binding protein 1(XBP1)splicing.We identified a binding site of XBP1 in the hIAPP promoter.Disruption of this binding site by substitution or deletion mutagenesis significantly diminished the effects of ER stress on hIAPP promoter activity.Blockade of XBP splicing by MKC3946 treatment inhibited ER stress-induced hIAPP up-regulation and improved human b-cell survival and function.Our study uncovers a link between ER stress and IAPP at the transcriptional level and may provide novel insights into the role of ER stress in IAPP cytotoxicity and the pathogenesis of T2DM.
