Transcriptomics and single-cell RNA sequencing analysis of long-term cultured human islets in vitro [RNA-Seq]

β-cell dysfunction in pancreatic islets is the leading cause of progression to type I diabetes (T1D), but the reason for the loss of β-cell mass in T1D is still not fully understood. Using in vitro long-term cultured (LTC) human islets, we have investigated gene profiling and subtype cells changes in the leftover cells and compared them with residual cells in samples of T1D or T2D. While most of the dysregulated genes were downregulated during LTC, we found there are specific groups of mRNA or miRNA that were upregulated, and they are involved in specific pathways. In general, α-cells and β-cells of LTC-islets have elevated expressions of MAFB and MAFA, respectively. We also found exocrine cells were eliminated faster than endocrine cells, and β-cells were lost at a higher rate than α-cells. Interestingly, a specific group of cells that were classified as α-cells but have immature β-cells-like characteristics, were enriched in LTC, revealed the possibility of transdifferentiating of α-cells to β-cells under in vitro culture. Our results suggested that there are intrinsic cellular and molecular mechanisms in pancreatic cells that are associated with their maturity and correlated with their survival ability under unfavorable living conditions.