Pro‐inflammatory activation of microglia in the cerebellum hyperexcites Purkinje cells to trigger ataxia

ABSTRACT: Specific medications to combat cerebellar ataxias, a group of debilitating movement disorders characterized by difficulty with walking, balance and coordination. Notably, cerebellar microglial activation appears to be a common feature in different types of ataxic patients and rodent models. However, the causal link between the activation of microglia in the cerebellum and ataxias remains inconclusive. In the present study, using a classic mouse model of cerebellar ataxia induced by 3-acetylpyridine (3-AP), we find a early-onset and long-lasting microglial activation accompanied by neuronal loss and dysfunction in the cerebellum. Transcriptome and behavior analyses indicate that microglial depletion in 3-AP ataxic mice decreases neuroinflammatory response in the cerebellum and rescues the ataxic motor symptoms including motor incoordination, gait abnormality, and locomotor dysfunction. Moreover, specific chemogenetic activation of cerebellar microglia in the vermis by M3D(Gq), a designer receptor exclusively activated by designer drugs (DREADDs), directly induces an expression of pro-inflammatory cytokines and aggravates ataxic motor deficits of 3-AP mice. On the contrary, inhibition of cerebellar microglial activation by M4D(Gi) or minocycline reduces the production of pro-inflammatory cytokines including TNF-α and alleviates motor deficits. Furthermore, blockage of TNF-α signaling attenuates the microglial-triggered hyperactivity of Purkinje cells (PCs). These results suggest that cerebellar microglial activation aggravates neuroinflammatory response, and subsequently induces dysfunction of PCs, which in turn triggers ataxic motor deficits. Our findings thus reveal a causal relationship between pro-inflammatory activation of cerebellar microglia and the ataxic motor symptoms, which may offer novel evidence for therapeutic intervention for cerebellar ataxias by targeting microglia and microglia-derived inflammatory mediators.

ORGANISM(S): Mus musculus

PROVIDER: GSE221991 | GEO | 2023/07/01

REPOSITORIES: GEO