Elucidating how transcription factors MAFA and MAFB and mitochondrial activity control human β cell identity and function

阐明转录因子 MAFA 和 MAFB 以及线粒体活性如何控制人类细胞的身份和功能

• 批准号: 10660007
• 负责人: Emily M Walker
• 金额: $ 14.25万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-04-01 至 2028-02-29
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10660007
• 关键词: Adult; Affect; B-Lymphocytes; Back; Beta Cell; Biogenesis; Biological Assay; Blood Glucose; Cell Differentiation process; Cell Line; Cell Maturation; Cell physiology; Cells; Complement Factor B; Consumption; Data; Defect; Diabetes Mellitus; Equilibrium; Etiology; Failure; Feedback; Functional disorder; Future; Gene Expression; Gene Expression Profile; Gene Expression Profiling; Gene Expression Regulation; Gene Targeting; Genes; Genetic; Genetic Transcription; Glucose; Health; Homo; Human; Impairment; Insulin; Life Cycle Stages; Metabolic; Metabolic Control; Mitochondria; Mitochondrial DNA; Mus; Non-Insulin-Dependent Diabetes Mellitus; Nuclear; Oxidative Stress; Oxygen Consumption; Pathway interactions; Patients; Phosphotransferases; Physiological; Proteins; Regulation; Reporting; Role; Signal Transduction; Structure; Testing; Transplantation; biological adaptation to stress; blood glucose regulation; cell dedifferentiation; factor A; functional restoration; human embryonic stem cell; humoral immunity deficiency; in vivo; insulin secretion; islet; knock-down; maturity onset diabetes of the young; metabolomics; mitochondrial dysfunction; oxidative damage; pharmacologic; programs; response; single-cell RNA sequencing; stem cells; targeted treatment; tool; transcription factor

Project Summary Type 2 diabetes (T2D) can be attributed to loss of β-cell identity or de-differentiation, marked by acquisition of immature cell markers and loss of insulin expression and secretion. While the etiology of β-cell immaturity in T2D is unclear, impairments in nuclear-encoded mitochondrial gene expression and transcription factor (TF) expression occur. Additionally, defects in mitochondrial structure and function leads to impaired glucose- stimulated insulin secretion (GSIS) and have been reported in β-cells of human T2D patients. Interestingly, the transcriptional changes that occur during β-cell immaturity involve loss of the nuclear-encoded mitochondrial gene expression program. My studies will test the hypothesis that β-cell immaturity in T2D is driven by loss of mitochondrial functional gene regulation by the TFs MAF bZIP transcription factor A (MAFA) or B (MAFB). Furthermore, I predict that MAFA/MAFB are themselves targets of mito-nuclear crosstalk through a retrograde signaling cascade induced by defects in mitochondrial function. I will elucidate the contribution of MAFA and MAFB on metabolic control in human β cells through regulation of mitochondrial function (Aim 1). I will determine how loss of MAFA and/or MAFB affects mitochondrial function and β cell identity by assaying oxygen consumption and gene expression in MAFA and/or MAFB knockdown human pseudoislets and EndoC-βH3 β cell lines. Metabolomics will be performed on EndoC- βH3 β cell lines to determine how MAFA/B influences fuel utilization. My preliminary data shows that genetic loss of mitophagy (i.e., the balance of mitochondrial biogenesis and turnover) reduces β-cell maturity. This includes physiologic, metabolic, and transcriptional signatures consistent with metabolic overload, oxidative damage, and the integrated stress response (ISR). MAFA (and likely MAFB) is known to be more sensitive to oxidative stress associated with T2D β-cell dysfunction than other TFs. While nuclear expression of β-cell mitochondrial genes are well known, mitochondrial feedback to drive β-cell nuclear gene expression (retrograde signaling) has not been analyzed. I will delineate if TF levels and β-cell maturity are altered in response to mitochondrial dysfunction (Aim 2). Further, I observed that pharmacological inhibition of the ISR relieves markers of immaturity in islets of mitophagy-deficient mice. Utilizing pharmacologic tools and analysis of gene expression in human pseudoislet transplants and EndoC-βH3 cells, I will interrogate how such conditions impact human β cells. I expect that MAFA (and possibly MAFB) levels will be reduced because of their ISR sensitivity. Moreover, I will determine if inhibition of the ISR restores MAFA/MAFB expression and reverses β-cell immaturity in the background of mitochondrial damage.

项目概要 2 型糖尿病 (T2D) 可归因于 β 细胞特性丧失或去分化，其特征是获得 不成熟的细胞标志物以及胰岛素表达和分泌的丧失，而 T2D 中 β 细胞不成熟的病因。 尚不清楚，核编码线粒体基因表达和转录因子（TF）的损伤 此外，线粒体结构和功能的缺陷会导致葡萄糖受损。 刺激胰岛素分泌 (GSIS)，并已在人类 T2D 患者的 β 细胞中得到报道。 β细胞不成熟期间发生的转录变化涉及核编码线粒体的丢失 我的研究将验证 T2D 中 β 细胞不成熟是由基因表达缺失引起的假设。 线粒体功能基因由 TF MAF bZIP 转录因子 A (MAFA) 或 B (MAFB) 调节。 此外，我预测 MAFA/MAFB 本身就是通过逆行线粒体核串扰的目标 线粒体功能缺陷引起的信号级联反应。 我将通过以下方式阐明 MAFA 和 MAFB 对人类 β 细胞代谢控制的贡献 线粒体功能的调节（目标 1）我将确定 MAFA 和/或 MAFB 的损失如何影响。 通过测定 MAFA 和/或中的耗氧量和基因表达来确定线粒体功能和 β 细胞身份 MAFB 敲低人类伪胰岛和 EndoC-βH3 β 细胞系将​​在 EndoC- 上进行代谢组学。 βH3 β 细胞系以确定 MAFA/B 如何影响燃料利用 我的初步数据表明遗传损失。 线粒体自噬（即线粒体生物发生和周转的平衡）会降低 β 细胞的成熟度。 生理、代谢和转录特征与代谢超载、氧化损伤和 已知综合应激反应 (ISR) 对氧化应激更敏感。 与 T2D β 细胞功能障碍相关性高于其他 TF，而 β 细胞线粒体基因的核表达。 众所周知，驱动 β 细胞核基因表达（逆行信号传导）的线粒体反馈尚未 我将描述 TF 水平和 β 细胞成熟度是否因线粒体功能障碍而改变。 （目标 2）此外，我观察到 ISR 的药理学抑制可减轻胰岛的不成熟标志。 利用药理学工具和分析人伪胰岛的基因表达。 移植和 EndoC-βH3 细胞，我将探究这些条件如何影响人类 β 细胞。 由于 ISR 敏感性，MAFA（可能还有 MAFB）水平会降低。此外，我将确定是否会降低。 抑制 ISR 可恢复 MAFA/MAFB 表达并逆转 β 细胞不成熟 线粒体损伤。