Objective

Altered gene expression contributes to the development of type 2 diabetes (T2D); thus, the analysis of differentially expressed genes between diabetes-susceptible and diabetes-resistant mouse models is an important tool for the determination of candidate genes that participate in the pathology. Based on RNA-seq and array data comparing pancreatic gene expression of diabetes-prone New Zealand Obese (NZO) mice and diabetes-resistant B6.V-ob/ob (B6-ob/ob) mice, the gap junction protein beta 4 (Gjb4) was identified as a putative novel T2D candidate gene.

Methods

Gjb4 was overexpressed in primary islet cells derived from C57BL/6 (B6) mice and INS-1 cells via adenoviral-mediated infection. The proliferation rate of cells was assessed by BrdU incorporation, and insulin secretion was measured under low (2.8 mM) and high (20 mM) glucose concentration. INS-1 cell apoptosis rate was determined by Western blotting assessing cleaved caspase 3 levels.

Results

Overexpression of Gjb4 in primary islet cells significantly inhibited the proliferation by 47%, reduced insulin secretion of primary islets (46%) and INS-1 cells (51%), and enhanced the rate of apoptosis by 63% in INS-1 cells. Moreover, an altered expression of the miR-341-3p contributes to the Gjb4 expression difference between diabetes-prone and diabetes-resistant mice.

Conclusions

The gap junction protein Gjb4 is highly expressed in islets of diabetes-prone NZO mice and may play a role in the development of T2D by altering islet cell function, inducing apoptosis and inhibiting proliferation.

中文翻译：

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Gjb4 的过度表达会损害原代胰岛细胞的细胞增殖和胰岛素分泌。

 客观的

基因表达改变导致 2 型糖尿病 (T2D) 的发展；因此，分析糖尿病易感小鼠模型和糖尿病抵抗小鼠模型之间的差异表达基因是确定参与病理学的候选基因的重要工具。根据比较易患糖尿病的新西兰肥胖 (NZO) 小鼠和抗糖尿病 B6.V -ob/ob (B6- ob/ob ) 小鼠的胰腺基因表达的 RNA-seq 和阵列数据，间隙连接蛋白 β4 ( Gjb4 ) 被鉴定为推定的新型 T2D 候选基因。

 方法

Gjb4通过腺病毒介导的感染在源自 C57BL/6 (B6) 小鼠的原代胰岛细胞和 INS-1 细胞中过表达。通过 BrdU 掺入评估细胞增殖率，并在低（2.8 mM）和高（20 mM）葡萄糖浓度下测量胰岛素分泌。通过蛋白质印迹法评估裂解的 caspase 3 水平来确定 INS-1 细胞凋亡率。

 结果

原代胰岛细胞中G​​jb4的过表达显着抑制了47％的增殖，减少了原代胰岛（46％）和INS-1细胞（51％）的胰岛素分泌，并使INS-1细胞的凋亡率增加了63％。此外，miR-341-3p 表达的改变导致易患糖尿病和耐糖尿病小鼠之间Gjb4表达差异。

 结论

间隙连接蛋白 Gjb4 在易患糖尿病的 NZO 小鼠胰岛中高表达，可能通过改变胰岛细胞功能、诱导细胞凋亡和抑制增殖在 T2D 的发展中发挥作用。