Secretory stimuli distinctly regulate insulin secretory granule maturation through structural remodeling

Area of Science:

• Cell Biology
• Endocrinology
• Biophysics

Background:

• Insulin secretory granule (ISG) maturation is vital for insulin secretion and glucose homeostasis.
• The regulation of ISG maturation and the impact of stimuli on their maturity and localization are not well understood.

Purpose of the Study:

• To quantitatively map ISG morphology, density, and location in response to various secretory stimuli.
• To understand how different stimuli uniquely affect ISG structure and cellular organization.

Main Methods:

• Soft X-ray tomography (SXT) was employed to analyze ISGs in INS-1E and mouse pancreatic beta-cells.
• Quantitative mapping of ISG morphology, density, and subcellular localization was performed.

Main Results:

• Activation of glucokinase (GK), GIPR, GLP-1R, and GPR40 was found to promote ISG maturation.
• Each stimulus induced specific structural remodeling of ISGs, affecting their size and density.
• Mobilization and redistribution of ISGs altered the overall cellular structural organization.

Conclusions:

• Secretory stimuli differentially regulate ISG maturation through distinct signaling pathways.
• Findings provide insights into how current diabetes and obesity therapies affect ISG maturation.
• This study may inform the development of novel therapeutic strategies targeting ISG maturation.