BACKGROUND: Protein tyrosine phosphatases (PTPs) play key roles in β-cell function and diabetes development. PTPN2 is a candidate gene for type 1 diabetes (T1D) that negatively regulates JAK/STAT signalling. However, the impact of PTPN2 deficiency on the differentiation and functionality of human stem cell-derived somatic metabolic cells remains unclear.
METHODS: PTPN2 expression in β cells from T1D organ donors and during the differentiation of human stem cell-derived islets (SC-islets) was evaluated using single-cell RNA-Sequencing (scRNA-Seq) datasets. We differentiated CRISPR-Cas12a genome-edited PTPN2-deficient H1 human embryonic stem cells (H1-hESCs) into SC-islets, and scRNA-Seq was performed. The maturation and functionality of PTPN2-deficient SC-islets were assessed by implantation under the kidney capsule of NOD-SCID mice.
RESULTS: scRNA-Seq analysis showed that PTPN2 expression was increased in β cells from recently diagnosed T1D and decreased in long-standing T1D organ donors compared with controls. Conversely, we found that PTPN2 expression was decreased at the early stages of SC-islet differentiation and reconstituted at the later stages, suggesting a developmental dynamic. PTPN2 deficiency exacerbated interferon-induced inflammatory signalling in stem cells and differentiated somatic metabolic cells. Interestingly, PTPN2 deficiency increased hedgehog signalling and reduced SC-islet differentiation efficiency in vitro. In addition, PTPN2-knockout SC-islets exhibited reduced glycaemic control after implantation in vivo, mediated by reduced endocrine cell identity and enhanced interferon signalling.
CONCLUSIONS: Our study postulates a key role of PTPN2 in preserving β-cell function during inflammatory and metabolic stress in SC-islets.
