TDP-43 pathology triggers neuroinflammation and cognitive impairment by inducing microglial necroptosis.

Abstract

Pathological TAR DNA-binding protein-43 (TDP-43) is a defining feature of several neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD) and Alzheimer's disease (AD). However, the mechanism by which TDP-43 pathology disrupts microglial function and drives neuroinflammation remains unclear. In this study, we demonstrated that cytoplasmically mis-localized TDP-43 exacerbated neuroinflammation, induced cell death, and impaired phagocytic function in microglial cells, primarily through receptor interacting serine/threonine kinase 3 (RIPK3)-dependent necroptosis. Pharmacological inhibition of RIPK3 with GSK872 markedly attenuated these pathological effects in vitro. These findings were further corroborated in a murine model with cytoplasmic TDP-43 mis-localization, where GSK872 treatment remarkably alleviated neuroinflammation and restored cognitive deficits. Mechanistically, our findings indicate that the nuclear depletion of TDP-43, resulted from its cytoplasmic mis-localization, impairs its ability to transcriptionally repress the Ripk3 gene, subsequently leading to RIPK3 upregulation and activation of RIPK3-dependent necroptosis. Collectively, our findings establish RIPK3-dependent necroptosis as a critical driver of TDP-43 pathology-mediated neuroinflammation and identified necroptosis as a promising therapeutic target in TDP-43-associated neurodegenerative disorders.