Inhibition of Insulin Secretion Induces Golgi Morphological Changes.

OBJECTIVES

The role of autophagy in pancreatic β cells has been reported, but the relationship between autophagy and insulin metabolism is complex and is not fully understood yet.

DESIGN

We here analyze the relationship between autophagy and insulin metabolism from a morphological aspect.

METHODS

We observe the morphological changes of β cell-specific Atg7-deficient mice and Atg5-deficient MIN6 cells with electron microscopy.

RESULTS

We find that Atg7-deficient β cells exhibit a marked expansion of the endoplasmic reticulum (ER). We also find that the inhibitory state of insulin secretion causes morphological changes in the Golgi, including ministacking and swelling. The same morphological alterations are observed when insulin secretion is suppressed in Atg5-deficient MIN6 cells.

CONCLUSIONS

The defect of autophagy induces ER expansion, and inhibition of insulin secretion induces Golgi swelling, probably via ER stress and Golgi stress, respectively.