Autophagy is known to play a pivotal role in intracellular quality control through the degradation of subcellular damaged organelles and components. Whereas autophagy is essential for maintaining β-cell function in pancreatic islets, it remains unclear as to how the cellular autophagy affects the homeostasis and function of glucagon-secreting α cells. To analyze the role of autophagy in α cells, we generated a mutant mouse model lacking Atg7, a key molecule for autophagosome formation, specifically in α cells. Histological analysis demonstrated an increased number of glucagon-positive cells, with a multilayered structure, in the islets under Atg7 deficiency, although metabolic profiles, such as body weight, blood glucose and plasma glucagon levels, were comparable between Atg7-deficient mice and control littermates. Consistent with our previous findings that Atg7 deficiency suppressed β-cell proliferation, cellular proliferation was suppressed in Atg7-deficient α cells.

These findings suggest that α-cell autophagy plays a role in maintaining α-cell mass and normal islet architecture, but appears to be dispensable for metabolic homeostasis.

Disclosure

M. Himuro: None. T. Miyatsuka: None. L. Suzuki: None. M. Miura: None. T. Katahira: None. H. Goto: None. Y. Nishida: None. S. Sasaki: None. Y. Fujitani: Research Support; Self; Takeda Pharmaceutical Company Limited. H. Watada: Research Support; Self; Astellas Pharma Inc., Boehringer Ingelheim Pharmaceuticals, Inc., Daiichi Sankyo Company, Limited, Kissei Pharmaceutical Co., Ltd., Merck Sharp & Dohme Corp., Mitsubishi Tanabe Pharma Corporation, Novartis Pharmaceuticals Corporation, Novo Nordisk A/S, Pfizer Inc., Sanofi, Sumitomo Dainippon Pharma Co., Ltd., Takeda Pharmaceutical Company Limited, Teijin Pharma Limited. Speaker's Bureau; Self; Astellas Pharma Inc., Boehringer Ingelheim Pharmaceuticals, Inc., Daiichi Sankyo Company, Limited, Eli Lilly and Company, Merck Sharp & Dohme Corp., Mitsubishi Tanabe Pharma Corporation, Novo Nordisk A/S, Ono Pharmaceutical Co., Ltd., Sanofi, Takeda Pharmaceutical Company Limited, Terumo Medical Corporation. Other Relationship; Self; Boehringer Ingelheim Pharmaceuticals, Inc., Kowa Pharmaceutical Europe Co. Ltd., Merck Sharp & Dohme Corp., Mitsubishi Tanabe Pharma Corporation, Ono Pharmaceutical Co., Ltd., Sanwa Chemical Industry Co. Ltd., Takeda Pharmaceutical Company Limited.

Funding

Japan Society for the Promotion of Science

© 2019 by the American Diabetes Association.
2019
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