Högskolan i Skövde

Type 2 diabetes (T2D) is a widespread metabolic disorder characterized by chronic hyperglycemia and insulin resistance (IR), impacting over 90% of diabetes cases globally. Despite extensive research, the precise molecular mechanisms of T2D remain unclear, highlighting the need for further investigation into its pathophysiology. This study aims to elucidate the relationship between pancreatic islet cell electrophysiological activity and gene expression profiles to enhance our understanding of T2D’s cellular mechanisms.

Pancreatic islets from non-diabetic mice and humans were isolated, dissociated into single cells, and analyzed using high-density microelectrode arrays (HD-MEA) for electrophysiological across various glucose concentrations. The electrophysiological was monitored over 3-5 days, with validation through calcium fluorescence imaging. Single-cell RNA sequencing (scRNA-seq) was employed to analyze gene expression changes for alpha and beta cell types.

Results revealed distinct electrophysiological patterns in response to glucose, with variations inspike frequency. Differential gene expression analysis identified gene expression changes in alpha and beta cells. The TRIB3 and FFAR4 genes were found to be downregulated in T2D compared tonon-diabetic non-obese (NN) individuals, and both are involved in glucose transmembrane transport. Additionally, FFAR4 showed reduced expression in T2D relative to non-diabetic obese(NO) individuals, and is associated with peptide hormone secretion. Conversely, PDE4B was upregulated in T2D compared to NO individuals, impacting calcium channel voltage gating and cAMP signaling pathways. FXYD2, related to sodium channel regulation, was also downregulated in T2D compared to NO individuals. In alpha cells, the genes TMEM236, TMEM45B, and SYTL5 were upregulated in T2D compared to both NN and NO individuals, suggesting alterations in cellular membrane dynamics and signaling pathways.

The integration of HD-MEA with scRNA-seq provided insights into the functional and transcriptomic profiles of human pancreatic islets under different metabolic states. Findings highlight significant changes in gene expression and electrophysiology, emphasizing the impactof T2D and obesity on islet function. While this study enhances our understanding of islet dysfunction in T2D, it also points to limitations such as small sample sizes and the focus on only alpha and beta cells, suggesting the need for broader studies to further elucidate T2D mechanisms.