USP28 potentiates endothelial necroptosis via deubiquitinating NMMHC IIA in septic male mice

Endothelial dysfunction contributes to multi-organ injury in sepsis, but the underlying mechanisms remain incompletely understood. Here we show that endothelial ubiquitin-specific protease 28 (USP28) is increased in patients with sepsis and in male mice in a murine polymicrobial sepsis model. Mechanistically, USP28 stabilizes non-muscle myosin heavy chain IIA (NMMHC IIA) by removing K48-linked ubiquitination at K1413. Moreover, NMMHC IIA promotes interferon-α/β receptor 1 (IFNAR1) trafficking to the plasma membrane, enhancing IFNAR1/signal transducer and activator of transcription 1 (STAT1) signaling and endothelial necroptosis. In turn, STAT1 transcriptionally increases USP28 expression, forming a positive feedback loop. Endothelial USP28 deletion or pharmacological inhibition attenuates sepsis-induced multi-organ injury, whereas USP28 overexpression exacerbates it. Conversely, endothelial NMMHC IIA or IFNAR1 overexpression largely abrogates the protection conferred by USP28 deficiency in septic male mice. These findings identify a USP28–NMMHC IIA axis that promotes endothelial necroptosis and multi-organ injury in sepsis through IFNAR1/STAT1 signaling.