Knockdown of RUVBL2 improves hnRNPA2/B1-stress granules dynamics to inhibit perioperative neurocognitive disorders in aged mild cognitive impairment rats.

Abstract

Perioperative neurocognitive disorders (PND) is common in aged mild cognitive impairment (MCI) patients and can accelerate the progression to dementia. This process involves heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNPA2/B1)-mediated aggregates of stress granules (SGs), while RUVBL2 influences the dynamics of these SGs. Our research explored a new target for modulating hnRNAPA2/B1-SGs dynamics to accelerate their disassembly and potentially delay MCI progression due to PND. We assessed the effect of hippocampal RUVBL2 knockdown on hnRNPA2/B1-SGs in aged MCI rats through behavioral studies, biochemical experiments and MRI. We also examined hnRNPA2/B1-SGs dynamics using immunofluorescence staining and fluorescence recovery after photobleaching (FRAP) in rat primary hippocampal neurons. Our results revealed that hnRNPA2/B1 in the hippocampus of aged MCI rats translocates to the cytoplasm to form SGs following anesthesia. RUVBL2 knockdown promotes the disappearance of hnRNPA2/B1-SGs, allowing hnRNPA2/B1 to return to the nucleus and enhancing functional activity in the brain regions of aged MCI rats. In primary hippocampal neurons, RUVBL2 deletion facilitated hnRNPA2/B1-SGs transition from hydrogel to liquid, promoting disassembly. We compared three commonly used general anesthetics-3% sevoflurane, 40 mg·kg^-1·h^-1 propofol, and 9% desflurane. Sevoflurane upregulated RUVBL2, which decreased the intraneuronal pH and disrupted energy metabolism. These changes resulted in greater stabilization of hnRNPA2/B1- SGs. In conclusion, our findings indicated that the knockdown of RUVBL2 expression contributes to the transition of hnRNPA2/B1-SGs from the hydrogel phase to the liquid phase. Targeted interference with RUVBL2 may represent a novel approach to delay the progression to dementia due to PND in aged MCI patients.