HSP70 activates selective autophagy via UBQLN2 to alleviate hSOD1G93A-mediated neurotoxicity in NSC-34 cellular model of ALS

Abstract Purpose: To determine whether HSP70 restores damaged autophagic flux via UBQLN2 to counteract SOD1 mutant neurotoxicity and elucidate the UBQLN2-HSP70 mechanism in ALS proteostasis. Methods: Human wild‑type (WT) and G93A mutant (MUT) SOD1 eukaryotic expression plasmids were constructed and transiently transfected into NSC34 cells to establish an hSOD1 G93A -ALS cell model. Eight groups were set up: blank control, empty-vector, WT, MUT, HSP70-overexpressing, HSP70-knockdown, UBQLN2-knockdown, and rapamycin-treated (positive control) groups. Cell viability was assessed by CCK‑8 assay; Protein levels of SOD1, LC3‑II, p62, HSP70, and UBQLN2 were measured by Western blot; The HSP70‑UBQLN2 interaction was verified by co‑immunoprecipitation (Co‑IP). Results: The hSOD1 G93A -NSC34 model was successfully established. Compared with controls, model cells (MUT) showed lower viability ( p p p p p p p p p p p p Conclusion : In hSOD1 G93A ‑ALS,HSP70 restores damaged autophagic flux and promotes mutant SOD1 clearance through UBQLN2 mediation. UBQLN2 is a necessary medium for HSP70 to exert neuroprotective effects. Targeting the UBQLN2-HSP70 axis is expected to become a new strategy to interfere with the imbalance of ALS protein homeostasis.