A sulfated manno-glucuronan ameliorates β-cell dysfunction in type 2 diabetes by targeting ALDH1A3

Area of Science:

• Biochemistry
• Endocrinology
• Cell Biology

Background:

• Pancreatic beta-cell dysfunction is a key driver of type 2 diabetes mellitus (T2DM).
• Identifying novel compounds that protect and restore beta-cell function is crucial for T2DM treatment.
• Sulfated polysaccharides represent a class of molecules with potential therapeutic applications.

Purpose of the Study:

• To investigate the effects of sulfated manno-glucuronan (GMn) on pancreatic beta-cell function and viability.
• To elucidate the underlying molecular mechanisms of GMn's action in T2DM models.
• To evaluate GMn's therapeutic potential for T2DM.

Main Methods:

• In vitro studies using MIN6 cells and primary mouse islets exposed to palmitic acid (PA).
• In vivo studies using high-fat diet/streptozotocin-induced T2DM mouse models.
• Analysis of beta-cell function, insulin secretion, cell viability, gene expression (ALDH1A3, PDX1, NKX6.1, MAFA, NeuroD1), and cell proportions.

Main Results:

• GMn showed no cytotoxicity and protected beta cells from PA-induced damage.
• GMn dose-dependently reversed PA-impaired glucose-stimulated insulin secretion (GSIS).
• In vivo, GMn attenuated hyperglycemia, increased insulin content, and modulated islet cell populations.
• GMn suppressed ALDH1A3 expression and retinol metabolism, while enhancing beta-cell transcription factors.

Conclusions:

• GMn demonstrates protective and restorative effects on pancreatic beta cells.
• GMn's mechanism involves downregulating ALDH1A3 and promoting beta-cell identity markers.
• GMn holds promise as a novel therapeutic agent for type 2 diabetes mellitus.