β-Cell Succinate Dehydrogenase Deficiency Triggers Metabolic Dysfunction and Insulinopenic Diabetes

Area of Science:

• Cell Biology
• Metabolic Diseases
• Mitochondrial Biology

Background:

• Mitochondrial dysfunction is implicated in type 2 diabetes (T2D) pathogenesis.
• The specific role of succinate dehydrogenase (SDH) in pancreatic beta-cell failure remains unclear.

Purpose of the Study:

• To investigate the role of SDH deficiency in beta-cell dysfunction and insulinopenic diabetes.
• To elucidate the molecular mechanisms linking SDH deficiency to beta-cell failure.

Main Methods:

• Analysis of human diabetic samples and a beta-cell-specific SDH-ablated mouse model (SDHBbetaKO).
• Assessment of mitochondrial respiration, membrane potential, ATP production, and insulin secretion.
• Metabolomic and transcriptomic analyses to identify molecular alterations.
• Evaluation of mTOR inhibition using rapamycin.

Main Results:

• SDH deficiency impairs glucose-induced oxidative phosphorylation and mitochondrial membrane potential in beta-cells.
• Loss of SDH leads to succinate accumulation, activating mTOR complex 1 and promoting anabolic processes like lipid synthesis.
• These SDH deficiency-induced changes mimic human diabetic beta-cell dysfunction and are partially reversed by rapamycin.

Conclusions:

• SDH deficiency is a key driver of mitochondrial dysfunction and progressive beta-cell failure in T2D.
• mTOR complex 1 inhibition presents a potential therapeutic avenue for mitigating T2D-associated beta-cell loss.