Human antigen R regulates hypoxia-induced mitophagy in renal tubular cells through PARKIN/BNIP3L expressions

Area of Science:

• Cellular Biology
• Renal Pathophysiology
• Molecular Mechanisms

Background:

• Mitochondrial dysfunction is central to acute kidney injury (AKI) pathophysiology.
• Mitophagy, the selective degradation of damaged mitochondria, is crucial for maintaining cellular homeostasis.
• RNA-binding proteins (RBPs) play vital roles in regulating gene expression and cellular functions.

Purpose of the Study:

• To investigate the role of human antigen R (HuR) in hypoxia-induced mitophagy within renal tubular cells.
• To elucidate the molecular mechanisms by which HuR influences mitophagy pathways.

Main Methods:

• Western blot analysis to quantify mitophagy markers (PARKIN, PINK1, BNIP3L, etc.).
• Immunofluorescence microscopy to visualize mitophagosomes, mitolysosomes, and protein co-localization.
• RNA-immunoprecipitation and RNA stability assays to assess HuR-mRNA interactions and regulation.

Main Results:

• Hypoxia induced mitochondrial dysfunction and activated mitophagy, upregulating PARKIN, PINK1, BNIP3, and BNIP3L.
• HuR knockdown impaired hypoxia-induced mitophagosome and mitolysosome formation.
• HuR directly bound to PARKIN and BNIP3L mRNA under hypoxia, stabilizing them and increasing their expression.

Conclusions:

• HuR plays a critical role in regulating mitophagy in renal tubular cells under hypoxic conditions.
• HuR enhances mitophagy by stabilizing PARKIN and BNIP3L mRNA, thereby promoting the clearance of damaged mitochondria.
• These findings highlight HuR as a potential therapeutic target for AKI associated with mitochondrial dysfunction.