Restoring microRNA-499-5p Protects Sepsis-Induced Lung Injury Mice Via Targeting Sox6

Area of Science:

• Molecular Biology
• Immunology
• Pathology

Background:

• Sepsis is a life-threatening condition associated with significant organ damage.
• MicroRNAs (miRs) play a crucial role in the pathogenesis of sepsis.
• Sepsis-induced lung injury (SILI) is a major complication of sepsis.

Purpose of the Study:

• To investigate the protective role of miR-499-5p in a mouse model of sepsis-induced lung injury.
• To determine if miR-499-5p exerts its effects by targeting the sex-determining region Y-related high-mobility-group box 6 (Sox6) gene.
• To evaluate miR-499-5p as a potential therapeutic target for SILI.

Main Methods:

• A mouse model of sepsis-induced lung injury was established using cecal ligation and puncture.
• Assessed lung injury markers including wet/dry weight ratio, histological scores, collagen deposition, and pulmonary fibrosis.
• Quantified expression of miR-499-5p, Sox6, apoptosis markers (Caspase-3, Caspase-9, TUNEL), inflammatory factors, and oxidative stress indices.
• Employed loss- and gain-of-function assays to elucidate the regulatory relationship between miR-499-5p and Sox6.

Main Results:

• Sepsis induction led to increased lung W/D ratio and Sox6 expression, alongside decreased miR-499-5p levels.
• Restoration of miR-499-5p or depletion of Sox6 significantly ameliorated lung pathology and fibrosis.
• Treatment reduced apoptosis, inflammatory cytokine levels in bronchoalveolar lavage fluid and lung tissue, and oxidative stress.

Conclusions:

• High expression of miR-499-5p attenuates sepsis-induced lung injury by downregulating Sox6.
• This mechanism involves reducing cell apoptosis and inhibiting inflammation in lung tissues.
• miR-499-5p represents a promising therapeutic target and biomarker for sepsis-induced lung injury.