P2X7R deficiency alleviates cardiac senescence by enhancing mitophagy via the HuR/TRIM26/NR4A1 axis.

Serum levels of P2X7R increase with advancing age in humans and P2X7R expression is upregulated during cardiac senescence in mice.

• P2X7R expression was assessed in human serum samples across different age groups
• P2X7R upregulation was observed in mouse cardiac tissue during senescence
• Two mouse ageing models were used: natural ageing (20-month-old mice) and chronic subcutaneous D-galactose (D-gal) injection

P2X7R deficiency alleviates ageing-related cardiac dysfunction, senescence phenotypes, and impaired mitophagy.

• P2X7R knockout (P2X7R-/-) mice were used to assess the role of P2X7R in cardiac ageing
• Cardiac function and histopathological changes in cardiac tissues were evaluated in P2X7R-/- mice
• P2X7R deficiency reduced senescence phenotypes and improved mitophagy in ageing hearts
• Both natural ageing (20-month) and D-gal-induced ageing models were used to confirm findings

Cardiomyocyte-specific overexpression of P2X7R exacerbates myocardial dysfunction, senescence phenotype, and mitophagy disruption induced by D-galactose.

• Recombinant adeno-associated virus serotype 9 (AAV9) was employed to achieve cardiac-specific overexpression of P2X7R
• P2X7R overexpression worsened D-gal-induced myocardial dysfunction
• P2X7R overexpression increased senescence phenotypes and disrupted mitophagy in cardiomyocytes
• Findings confirm a gain-of-function role for P2X7R in cardiac ageing

P2X7R promotes HuR nucleocytoplasmic shuttling in ageing hearts, thereby increasing the mRNA stability of TRIM26 and expression of the E3 ubiquitin ligase TRIM26.

• Transcriptome sequencing was applied to elucidate the potential mechanisms of P2X7R in cardiac senescence
• P2X7R activation facilitated the shuttling of human antigen R (HuR) from nucleus to cytoplasm
• HuR binding to TRIM26 mRNA increased its stability and thus TRIM26 protein expression
• TRIM26 is identified as an E3 ubiquitin ligase in this signalling pathway

TRIM26 mediates NR4A1 ubiquitination and proteasomal degradation, which suppresses mitophagy in cardiomyocytes and accelerates cardiac ageing.

• TRIM26 was identified as the E3 ubiquitin ligase responsible for NR4A1 ubiquitination
• NR4A1 (nuclear receptor subfamily 4 group A member 1) undergoes proteasomal degradation following TRIM26-mediated ubiquitination
• NR4A1 degradation suppresses mitophagy in cardiomyocytes
• AAV9-mediated cardiac-specific overexpression of NR4A1 was used to validate its role in the pathway
• The complete axis identified is HuR/TRIM26/NR4A1 as the key signalling pathway through which P2X7R regulates cardiac ageing