Insufficient TRPM5 Mediates Lipotoxicity-induced Pancreatic β-cell Dysfunction.

Area of Science:

• Endocrinology
• Cell Biology
• Metabolic Diseases

Background:

• Transient receptor potential channel subfamily M member 5 (TRPM5) reduction is observed in type 2 diabetic mouse models.
• The specific role of TRPM5 in lipotoxicity-induced pancreatic beta-cell dysfunction is not fully understood.

Purpose of the Study:

• To investigate the role of TRPM5 in pancreatic beta-cell dysfunction induced by lipotoxicity.

Main Methods:

• Examined TRPM5 expression in pancreatic islets from high-fat-diet (HFD) fed mice using immunofluorescence.
• Induced lipotoxicity in primary mouse islets and MIN6 cells using palmitate (Palm).
• Assessed TRPM5 expression via qRT-PCR and Western blotting, and measured glucose-stimulated insulin secretion (GSIS) after Trpm5 knockdown or overexpression.

Main Results:

• HFD feeding and palmitate treatment significantly decreased TRPM5 mRNA and protein levels in pancreatic islets and MIN6 cells.
• Trpm5 knockdown impaired GSIS but did not affect insulin biosynthesis.
• Trpm5 overexpression reversed palmitate-induced GSIS defects and restored beta-cell maturation markers.

Conclusions:

• Lipotoxicity inhibits TRPM5 expression in pancreatic beta cells both in vivo and in vitro.
• Reduced TRPM5 expression is a key mechanism driving lipotoxicity-induced beta-cell dysfunction.