USP14-mediated deubiquitination of KRT19 promotes pyroptosis in myocardial ischemia/reperfusion injury.

Background

Myocardial ischemia/reperfusion (MI/R) injury remains a major clinical challenge characterized by inflammation and progressive cardiomyocyte loss. Although pyroptosis is known to drive this pathogenesis, the upstream molecular switches that trigger the pyroptotic cascade remain poorly understood. Here, we investigated the role of Keratin 19 (KRT19) and its regulation by the deubiquitinase USP14 in MI/R-induced pyroptosis.

Materials And Methods

In vivo mouse models of MI/R and in vitro neonatal mouse cardiomyocyte (NMCM) models of hypoxia/reoxygenation (H/R) were established. Following genetic manipulation of USP14 or KRT19, we evaluated cardiac function (via echocardiography), cell death (via flow cytometry and LDH release assays), mitochondrial function (via Seahorse analysis), and molecular interactions (via co-immunoprecipitation, domain-mapping, and ubiquitination assays).

Results

Both USP14 and KRT19 expression levels are significantly elevated in MI/R mouse hearts and H/R-exposed NMCMs. Knockdown of either USP14 or KRT19 mitigated NLRP3/Caspase-1/GSDMD-mediated pyroptosis both in vivo and in vitro. Mechanistically, USP14 interacted with KRT19 to prevent its K48-linked proteasomal degradation. Domain-mapping assays revealed that the C-terminal USP catalytic domain of USP14 bound to the Coil1B domain of KRT19. The resulting stabilization and accumulation of KRT19 promoted mitochondrial dysfunction and reactive oxygen species (mtROS) generation, thereby activating the pyroptotic cascade.

Conclusions

The USP14-KRT19 axis is a critical driver of cardiomyocyte pyroptosis and MI/R injury. Targeting this deubiquitination-mediated cytoskeletal stabilization cascade represents a promising therapeutic strategy to mitigate reperfusion injury.