Abstract Thu079: Preserving Nuclear Envelope Integrity Prevents Autosis

Autosis is a unique form of autophagic cell death that occurs during the late phase of ischemia/reperfusion in the heart, characterized by distinct morphological and biochemical features. However, the mechanisms by which dysregulated autophagy leads to this specific form of cell death remain unclear. In this study, we demonstrate that the LINC complex, which connects the nucleus to the cytoskeleton, plays a protective role in autosis. Tat-Beclin1, a known autosis inducer, disrupts nuclear morphology and induces an abnormal distribution of GFP-tagged Nesprin-3, an outer nuclear membrane protein, whereas this effect is not observed under apoptosis-inducing conditions. Nesprin-3 dispersion is also observed in cells subjected to EBSS treatment or hypoxia/reoxygenation, both of which can trigger autosis. The mislocalized Nesprin-3 shifts into a heavy membrane fraction and colocalizes with ER-RFP-positive vesicles, whereas SUN1, an inner nuclear membrane protein, remains unaffected. Moreover, Nesprin-3 undergoes degradation in a time-dependent manner, coinciding with LINC complex dissociation during autosis. Notably, Nesprin-3 overexpression enhances resistance to Tat-Beclin1-induced autosis, whereas a Nesprin-3 mutant lacking the KASH domain fails to provide protection. Furthermore, Nesprin-3 colocalizes with Vimentin, and its protective effect against autosis is lost in Vimentin-knockout cells. These findings provide new insights into how nuclear envelope integrity regulates autotic cell death and suggest potential therapeutic strategies for preventing autosis-associated heart diseases.