Monitoring autophagic flux in vivo revealed its physiological response and significance of heterogeneity in pancreatic beta cells

Shuhei Aoyama; Yuya Nishida; Hirotsugu Uzawa; Miwa Himuro; Akiko Kanai; Kyosei Ueki; Minami Ito; Hitoshi Iida; Isei Tanida; Takeshi Miyatsuka; Yoshio Fujitani; Masaki Matsumoto; Hirotaka Watada

doi:10.1016/j.chembiol.2023.03.001

Monitoring autophagic flux in vivo revealed its physiological response and significance of heterogeneity in pancreatic beta cells

Cell Chem Biol. 2023 Jun 15;30(6):658-671.e4. doi: 10.1016/j.chembiol.2023.03.001. Epub 2023 Mar 20.

Authors

Affiliations

¹ Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
² Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan. Electronic address: y-nishida@juntendo.ac.jp.
³ Department of Cellular and Molecular Neuropathology, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
⁴ Department of Endocrinology, Diabetes and Metabolism, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara 252-0374, Japan.
⁵ Laboratory of Developmental Biology and Metabolism, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi 371-8512, Japan.
⁶ Department of Omics and Systems Biology, Graduate School of Medical and Dental Sciences, Niigata University, 757 Ichibancho, Asahimachi-dori, Chuo-ku, Niigata City, Niigata 951-8510, Japan.

PMID: 36944338
DOI: 10.1016/j.chembiol.2023.03.001

Abstract

Autophagy plays an essential role in preserving cellular homeostasis in pancreatic beta cells. However, the extent of autophagic flux in pancreatic islets induced in various physiological settings remains unclear. In this study, we generate transgenic mice expressing pHluorin-LC3-mCherry reporter for monitoring systemic autophagic flux by measuring the pHluorin/mCherry ratio, validating them in the starvation and insulin-deficient model. Our findings reveal that autophagic flux in pancreatic islets enhances after starvation, and suppression of the flux after short-term refeeding needs more prolonged re-starvation in islets than in the other insulin-targeted organs. Furthermore, heterogeneity of autophagic flux in pancreatic beta cells manifests under insulin resistance, and intracellular calcium influx by glucose stimulation increases more in high- than low-autophagic flux beta cells, with differential gene expression, including lipoprotein lipase. Our pHluorin-LC3-mCherry mice enable us to reveal biological insight into heterogeneity in autophagic flux in pancreatic beta cells.

Keywords: autophagy; diabetes mellitus; heterogeneity; insulin resistance; insulin secretion; pHluorin; pancreatic beta cells.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Autophagy / physiology
Insulin / metabolism
Insulin-Secreting Cells* / metabolism
Islets of Langerhans* / metabolism
Mice
Mice, Transgenic

Substances

Insulin