Citrus flavonoid naringenin inhibits TLR2 expression in adipocytes

Area of Science:

• Biochemistry
• Immunology
• Metabolic Diseases

Background:

• Toll-like receptors (TLRs) play a role in obesity-induced adipose tissue inflammation, contributing to insulin resistance and type 2 diabetes.
• Regulating TLR expression is a potential therapeutic strategy for obesity-related conditions.

Purpose of the Study:

• To investigate the effect of naringenin, a citrus flavonoid, on Toll-like receptor 2 (TLR2) expression in adipocytes.
• To elucidate the molecular mechanisms underlying naringenin's anti-inflammatory effects in the context of obesity.

Main Methods:

• Assessed naringenin's impact on TLR2 expression during adipocyte differentiation.
• Examined naringenin's effects on TLR2 expression induced by co-cultured adipocytes and macrophages.
• Investigated naringenin's influence on tumor necrosis factor-α (TNF-α)-induced TLR2 expression via nuclear factor-κB (NF-κB) and c-Jun NH2-terminal kinase (JNK) pathways.
• Evaluated naringenin's effect on TLR2 expression in adipose tissue of high-fat diet-fed mice.

Main Results:

• Naringenin inhibited TLR2 expression during adipocyte differentiation, partly via peroxisome proliferator-activated receptor γ (PPARγ) activation.
• Naringenin suppressed TLR2 expression induced by adipocyte-macrophage co-culture and TNF-α stimulation.
• Naringenin reduced NF-κB and JNK pathway activation in adipocytes.
• Naringenin decreased adipose tissue TLR2 expression in mice fed a high-fat diet, correlating with improved hyperglycemia and reduced inflammatory mediators (TNF-α, MCP-1).

Conclusions:

• Naringenin demonstrates anti-inflammatory properties by inhibiting TLR2 expression in adipocytes.
• Naringenin's mechanism involves regulating TLR2 expression and associated inflammatory pathways.
• Naringenin shows potential therapeutic benefits for obesity-related diseases like insulin resistance and type 2 diabetes.