P53 modulates hepatic insulin sensitivity through NF-κB and p38/ERK MAPK pathways

Area of Science:

• Cell Biology
• Metabolic Disease Research
• Molecular Oncology

Background:

• The tumor suppressor p53 has recently been recognized for its role in metabolic regulation.
• Its specific function in insulin resistance remains controversial.
• Investigating p53's role in hepatic insulin resistance is crucial for understanding metabolic disorders.

Purpose of the Study:

• To investigate the expression and function of p53 in experimental models of insulin resistance.
• To determine the effect of p53 modulation on insulin signaling and glucose metabolism in hepatic cells.

Main Methods:

• Examined p53 protein levels in high-fat diet-induced insulin resistant mice, ob/ob diabetic mice, and palmitate-treated HepG2 cells.
• Utilized nutlin-3α (p53 activator) and pifithrin-α (p53 inhibitor) in HepG2 cells.
• Assessed glucose consumption, insulin signaling pathways, and activation of NF-κB, p38, and ERK1/2.

Main Results:

• p53 protein levels were decreased in insulin-resistant hepatic tissues and cells, correlating with increased phosphor-p38, ERK1/2, and NF-κB p65.
• Nutlin-3α treatment prevented palmitate-induced reduction in glucose consumption and insulin signaling, while downregulating inflammatory pathways.
• Pifithrin-α treatment decreased glucose consumption, suppressed insulin signaling, and activated NF-κB, p38, and ERK1/2 pathways.

Conclusions:

• p53 plays a protective role in hepatic insulin resistance.
• p53 improves insulin sensitivity by inhibiting mitogen-activated protein kinases (MAPKs) and NF-κB pathways.
• Modulating p53 activity represents a potential therapeutic strategy for metabolic disorders like insulin resistance.