C3aR1 on β cells enhances β cell function and survival

Area of Science:

• Immunology
• Endocrinology
• Metabolic Diseases

Background:

• Pancreatic beta cell dysfunction is a key factor in type 2 diabetes (T2D) development.
• Maintaining beta cell homeostasis is crucial for metabolic health, particularly under conditions like obesity.

Purpose of the Study:

• To investigate the role of the complement receptor C3aR1 on pancreatic beta cells in maintaining beta cell function and homeostasis.
• To elucidate the signaling axis between C3a and beta cell-expressed C3aR1 in the context of metabolic stress.

Main Methods:

• Generation of mice with beta cell-specific deletion of the C3ar1 gene (β-C3aR1 KO).
• Assessment of glucose tolerance, insulin levels, and beta cell mass in β-C3aR1 KO mice.
• Analysis of insulin secretion from isolated islets and examination of beta cell identity and stress markers.
• Evaluation of beta cell lipotoxicity and correlation of C3AR1 expression with insulin secretion in human islets.

Main Results:

• β-C3aR1 KO mice exhibited impaired glucose tolerance, reduced insulin levels, and decreased beta cell mass.
• Islets from β-C3aR1 KO mice showed impaired insulin secretion and an ablated response to C3a.
• Loss of C3aR1 led to decreased beta cell identity markers, increased stress markers, and heightened susceptibility to lipotoxicity.
• C3AR1 expression positively correlated with insulin secretion in human islets.

Conclusions:

• C3aR1 on pancreatic beta cells is essential for maintaining beta cell homeostasis and function, particularly under metabolic duress.
• The C3a-C3aR1 signaling axis plays a critical role in regulating beta cell function and survival.
• Targeting C3aR1 on beta cells may represent a therapeutic strategy for preserving beta cell function in type 2 diabetes.