SKAP2, a Candidate Gene for Type 1 Diabetes, Regulates β-Cell Apoptosis and Glycemic Control in Newly Diagnosed Patients.

The single nucleotide polymorphism rs7804356 located in the Src kinase-associated phosphoprotein 2 (SKAP2) gene is associated with type 1 diabetes (T1D), suggesting SKAP2 as a causal candidate gene. The objective of the study was to investigate if SKAP2 has a functional role in the β-cells in relation to T1D. In a cohort of children with newly diagnosed T1D, rs7804356 predicted glycemic control and residual β-cell function during the 1st year after diagnosis. In INS-1E cells and rat and human islets, proinflammatory cytokines reduced the content of SKAP2. Functional studies revealed that knockdown of SKAP2 aggravated cytokine-induced apoptosis in INS-1E cells and primary rat β-cells, suggesting an antiapoptotic function of SKAP2. In support of this, overexpression of SKAP2 afforded protection against cytokine-induced apoptosis, which correlated with reduced nuclear content of S536-phosphorylated nuclear factor-κB (NF-κB) subunit p65, lower nitric oxide production, and diminished CHOP expression indicative of decreased endoplasmic reticulum stress. Knockdown of CHOP partially counteracted the increase in cytokine-induced apoptosis caused by SKAP2 knockdown. In conclusion, our results suggest that SKAP2 controls β-cell sensitivity to cytokines possibly by affecting the NF-κB-inducible nitric oxide synthase-endoplasmic reticulum stress pathway. © 2020 by the American Diabetes Association.

Citation

Tina Fløyel, Kira Meyerovich, Michala C Prause, Simranjeet Kaur, Caroline Frørup, Henrik B Mortensen, Lotte B Nielsen, Flemming Pociot, Alessandra K Cardozo, Joachim Størling. SKAP2, a Candidate Gene for Type 1 Diabetes, Regulates β-Cell Apoptosis and Glycemic Control in Newly Diagnosed Patients. Diabetes. 2021 Feb;70(2):464-476

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PMID: 33203694

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