期刊
DIABETES
卷 70, 期 8, 页码 1717-1728出版社
AMER DIABETES ASSOC
DOI: 10.2337/db21-0037
关键词
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资金
- Canadian Institutes of Health Research
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) [R01-DK-090490]
- Department of Veterans Affairs [I01 BX005107]
- University of Iowa Pappajohn Biomedical Institute Convergence Pilot Grant
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa
- NIDDK [R01-DK-104998, 2UC4-DK-098085]
This study demonstrates that mitochondrial CIC is not essential for glucose-stimulated insulin secretion, and there are additional complexities in the role of Idh1 and NADPH in regulating beta-cell function.
The defining feature of pancreatic islet beta -cell function is the precise coordination of changes in blood glucose levels with insulin secretion to regulate systemic glucose homeostasis. While ATP has long been heralded as a critical metabolic coupling factor to trigger insulin release, glucose-derived metabolites have been suggested to further amplify fuel-stimulated insulin secretion. The mitochondrial export of citrate and isocitrate through the citrate-isocitrate carrier (CIC) has been suggested to initiate a key pathway that amplifies glucose-stimulated insulin secretion, though the physiological significance of beta -cell CIC-to-glucose homeostasis has not been established. Here, we generated constitutive and adult CIC beta -cell knockout (KO) mice and demonstrate that these animals have normal glucose tolerance, similar responses to diet-induced obesity, and identical insulin secretion responses to various fuel secretagogues. Glucose-stimulated NADPH production was impaired in beta -cell CIC KO islets, whereas glutathione reduction was retained. Furthermore, suppression of the downstream enzyme cytosolic isocitrate dehydrogenase (Idh1) inhibited insulin secretion in wild-type islets but failed to impact beta -cell function in beta -cell CIC KO islets. Our data demonstrate that the mitochondrial CIC is not required for glucose-stimulated insulin secretion and that additional complexities exist for the role of Idh1 and NADPH in the regulation of beta -cell function.
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