Circadian PER2 promotes T-2 toxin-induced immunosenescence by activating the hippo/MST1 signaling in macrophages

T-2 toxin induces severe cytotoxicity and immunosenescence, but the underlying mechanisms, particularly the role of circadian rhythm disruption, still lack a clear understanding. This study explores the function of the circadian PER2 and the Hippo/MST1 signaling in T-2 toxin-induced immunosenescence using RAW 264.7 macrophages model. We found that T-2 toxin (14 nM, 0-24 h) disrupted the oscillatory rhythm of PER2, attenuating its amplitude and altering its peak-trough pattern. This disruption was mediated by T-2 toxin-induced and sustained activation of HIF-1α, as HIF-1α inhibition significantly suppressed PER2 expression. Functionally, pharmacological inhibition of PER2 with KL044 alleviated T-2 toxin-induced senescence, as evidenced by reduced SA-β-gal activity, downregulation of SASP factors (IL-6, IL-8, CCL-2), and attenuation of G1 phase cell cycle arrest. Mechanistically, we identified that PER2 acts as a positive regulator of the Hippo/MST1 signaling. T-2 toxin activated Hippo signaling, increasing MST1 and phospho-YAP levels while reducing total YAP. PER2 inhibition blunted this activation. Crucially, direct inhibition of the Hippo kinase MST1 mirrored the protective effects of PER2 inhibition, significantly reducing cellular senescence, SASP expression, and Apoptosis. Our findings demonstrate that T-2 toxin promotes immunosenescence by hijacking the circadian PER2 via a HIF-1α-dependent mechanism. The upregulated PER2, in turn, activates the Hippo/MST1 signaling, driving senescence. This study unveils the PER2/Hippo axis as a novel signaling cascade critical for T-2 toxin-induced immunosenescence.