BECN1 regulates FADD/RIPK1/Caspase-8 complex formation via RIPK1 ubiquitination by downregulating OTUD1 in MI/R...

Area of Science:

• Molecular Biology
• Cardiovascular Research
• Cellular Apoptosis

Background:

• Cardiomyocyte apoptosis is a key factor in myocardial ischemia-reperfusion (MI/R) injury.
• The specific role of beclin1 (BECN1) in this process has not been fully elucidated.
• Understanding BECN1's function is crucial for developing therapeutic strategies against MI/R injury.

Purpose of the Study:

• To investigate the role of beclin1 (BECN1) in regulating cardiomyocyte apoptosis following MI/R injury.
• To elucidate the molecular mechanisms by which BECN1 influences cell death pathways in the context of MI/R.

Main Methods:

• In vivo studies utilized wild-type and BECN1-transgenic mice, employing TTC and Evan's blue staining, TUNEL assay, and western blotting to assess cardiac injury and apoptosis.
• In vitro experiments established a hypoxia/reoxygenation (H/R) model in H9c2 cells, analyzing apoptosis factors (RIPK1, Caspase-1, Caspase-3), mRNA levels (RT-PCR), and protein interactions (siRNA, lentiviral transfection, immunofluorescence, co-immunoprecipitation).
• Proteomics analysis was used to confirm apoptosis in the H/R cellular model.

Main Results:

• BECN1 significantly reduced cardiomyocyte apoptosis in vivo and in vitro, as evidenced by morphological and molecular analyses.
• BECN1 suppressed the formation of a RIPK1-FADD-Caspase-8 complex, a key initiator of apoptosis after H/R.
• BECN1 overexpression inhibited OTUD1, leading to increased RIPK1 ubiquitination and subsequent reduction in apoptosis.

Conclusions:

• BECN1 exerts a cardioprotective effect by modulating the FADD/RIPK1/Caspase-8 complex through RIPK1 ubiquitination, mediated by the downregulation of OTUD1.
• This mechanism effectively reduces cardiomyocyte apoptosis in the context of MI/R injury.
• BECN1 represents a promising therapeutic candidate for mitigating MI/R-induced cardiac damage.