Anthocyanins inhibit high-glucose-induced cholesterol accumulation and inflammation by activating LXRα pathway in...

Area of Science:

• Biochemistry
• Molecular Biology
• Pharmacology

Background:

• Diabetic nephropathy (DN) progression is linked to disrupted cholesterol metabolism and inflammation.
• Anthocyanins, found in food, possess antioxidant, anti-inflammatory, and lipid-lowering properties.
• The specific mechanisms of anthocyanins in DN, particularly regarding cholesterol efflux and inflammation, require further elucidation.

Purpose of the Study:

• To investigate the effects of anthocyanins (cyanidin-3-O-β-glucoside chloride [C3G] and cyanidin chloride [Cy]) on cholesterol metabolism and inflammation in high-glucose (HG)-stimulated HK-2 cells.
• To elucidate the molecular mechanisms underlying anthocyanin action, focusing on the interplay between cholesterol efflux and inflammatory pathways.

Main Methods:

• Utilized high-glucose (HG)-stimulated HK-2 cells to model aspects of diabetic nephropathy.
• Assessed the impact of anthocyanins on cholesterol efflux, ABCA1 expression, and the expression of key signaling molecules including PPARα, LXRα, and NFκB.
• Employed a PPARα-specific inhibitor (GW6471) and LXRα shRNA to investigate the roles of these receptors in mediating anthocyanin effects.
• Examined the expression of pro-inflammatory cytokines (ICAM1, MCP1, TGFβ1) and NFκB activation.

Main Results:

• Anthocyanins significantly enhanced cholesterol efflux and ABCA1 expression in HK-2 cells.
• Anthocyanins increased PPARα and LXRα expression and suppressed HG-induced pro-inflammatory cytokine expression (ICAM1, MCP1, TGFβ1) and NFκB activation.
• Inhibition of PPARα or LXRα attenuated anthocyanin-induced cholesterol efflux, indicating a PPARα-LXRα-ABCA1-dependent mechanism.
• LXRα knockout abolished the anti-inflammatory effects of anthocyanins, suggesting LXRα's crucial role in mediating these effects, potentially by modulating NFκB nuclear translocation.

Conclusions:

• Anthocyanins promote cholesterol efflux via the PPARα-LXRα-ABCA1 pathway in kidney cells.
• Anthocyanins exert anti-inflammatory effects in DN models, primarily through the LXRα pathway's influence on NFκB signaling.
• These findings highlight anthocyanins as potential agents for managing diabetic nephropathy by concurrently addressing cholesterol dysregulation and inflammation.