Molecular Diabetes Laboratory, Division of Endocrinology, Diabetes, Hypertension and Nutrition, University Hospital/Diabetes Center/University of Geneva Medical School, Geneva, Switzerland.
Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva, Switzerland.
PLoS One. 2019 Mar 8;14(3):e0213299. doi: 10.1371/journal.pone.0213299. eCollection 2019.
Characterization of endocrine-cell functions and associated molecular signatures in diabetes is crucial to better understand why and by which mechanisms alpha and beta cells cause and perpetuate metabolic abnormalities. The now recognized role of glucagon in diabetes control is a major incentive to have a better understanding of dysfunctional alpha cells. To characterize molecular alterations of alpha cells in diabetes, we analyzed alpha-cell transcriptome from control and diabetic mice using diet-induced obesity model. To this aim, we quantified the expression levels of total mRNAs from sorted alpha and beta cells of low-fat and high-fat diet-treated mice through RNAseq experiments, using a transgenic mouse strain allowing collections of pancreatic alpha- and beta-cells after 16 weeks of diet. We now report that pancreatic alpha cells from obese hyperglycemic mice displayed minor variations of their transcriptome compared to controls. Depending on analyses, we identified 11 to 39 differentially expressed genes including non-alpha cell markers mainly due to minor cell contamination during purification process. From these analyses, we identified three new target genes altered in diabetic alpha cells and potently involved in cellular stress and exocytosis (Upk3a, Adcy1 and Dpp6). By contrast, analysis of the beta-cell transcriptome from control and diabetic mice revealed major alterations of specific genes coding for proteins involved in proliferation and secretion. We conclude that alpha cell transcriptome is less reactive to HFD diet compared to beta cells and display adaptations to cellular stress and exocytosis.
鉴定糖尿病中内分泌细胞功能及其相关分子特征对于更好地理解α和β细胞为什么以及通过何种机制导致和持续存在代谢异常至关重要。现在人们认识到胰高血糖素在糖尿病控制中的作用，这是更好地理解功能失调的α细胞的主要动力。为了描述糖尿病中α细胞的分子变化，我们使用饮食诱导肥胖模型分析了对照和糖尿病小鼠的α细胞转录组。为此，我们通过 RNAseq 实验定量了低脂肪和高脂肪饮食处理的小鼠分选的α和β细胞中的总 mRNA 的表达水平，使用一种转基因小鼠品系，可以在饮食 16 周后收集胰腺的α和β细胞。我们现在报告说，与对照相比，肥胖高血糖小鼠的胰腺α细胞的转录组仅有轻微变化。根据分析的不同，我们鉴定了 11 到 39 个差异表达基因，包括主要由于纯化过程中细胞污染而产生的非α细胞标记物。从这些分析中，我们鉴定了三个在糖尿病α细胞中改变的新靶基因，这些基因与细胞应激和胞吐作用密切相关（Upk3a、Adcy1 和 Dpp6）。相比之下，对照和糖尿病小鼠的β细胞转录组分析显示了参与增殖和分泌的特定基因编码蛋白的重大改变。我们得出结论，与β细胞相比，α细胞转录组对 HFD 饮食的反应性较小，并且显示出对细胞应激和胞吐作用的适应。
