Ubiquitin ligase MDM2 mediates endothelial inflammation in Kawasaki disease vasculitis development

Area of Science:

• Cardiovascular Research
• Molecular Biology
• Immunology

Background:

• Kawasaki disease (KD) is a significant cause of acquired heart disease in children, often leading to coronary artery lesions (CALs).
• Signal transducer and activator of transcription 3 (STAT3) signaling plays a critical role in KD pathogenesis and is linked to CAL development.
• The precise regulatory mechanisms of STAT3, particularly ubiquitination, in KD remain largely unexplored.

Purpose of the Study:

• To investigate the role of ubiquitination in regulating STAT3 during Kawasaki disease.
• To identify the specific E3 ligase involved in STAT3 ubiquitination in KD.
• To elucidate the functional consequences of MDM2-STAT3 interaction in KD pathogenesis and CAL formation.

Main Methods:

• Bioinformatics analysis and immunoprecipitation assays to identify STAT3-interacting E3 ligases.
• Analysis of MDM2 expression in blood samples from KD patients before and after intravenous immunoglobulin (IVIG) treatment.
• In vitro studies using human coronary artery endothelial cells (HCAECs) and in vivo studies using a mouse model to examine MDM2-STAT3 signaling.

Main Results:

• Murine double minute 2 (MDM2) was identified as the E3 ligase responsible for STAT3 ubiquitination.
• MDM2 expression was decreased, while STAT3 and vascular endothelial growth factor A (VEGFA) levels were increased in KD patients with CALs and in a KD mouse model.
• MDM2 overexpression enhanced STAT3 ubiquitination, leading to decreased STAT3 and VEGFA levels, suggesting MDM2 acts as a negative regulator.

Conclusions:

• MDM2 functions as a negative regulator of STAT3 signaling in Kawasaki disease by promoting STAT3 ubiquitination.
• The MDM2-STAT3 ubiquitination pathway represents a potential therapeutic target for managing KD and preventing coronary artery lesions.