Alpk1 activates JAK2/STAT3 signaling to enhance M1-microglial activation in epileptic rats

Epilepsy is a chronic brain disorder characterized by recurrent, highly synchronous abnormal neuronal discharges leading to cerebral dysfunction. This study investigates the role of alpha kinase 1 (ALPK1), a pattern recognition receptor, in epilepsy.

ALPK1 expression and distribution were analyzed using the GSE190452 dataset and a pilocarpine-induced rat model. An adeno-associated virus delivering Alpk1 shRNA was injected intra-hippocampally into model rats, followed by seizure monitoring. Pathological changes were assessed via hematoxylin and eosin and Nissl staining. Primary microglia and BV2 cells transfected with Alpk1 siRNA were stimulated with kainic acid. Immunofluorescence, quantitative real-time polymerase chain reaction, and Western blot were used to evaluate M1 microglial marker and pro-inflammatory cytokines. Gene Set Enrichment Analysis (GSEA) was performed to identify potential signaling associated with Alpk1 function.

ALPK1 was widely distributed and highly expressed in epileptic microglia. Alpk1 knockdown alleviated seizure symptoms in rats, including hippocampal damage, Nissl body loss, reduced Racine scores, and decreased daily seizure frequency and duration. Both in vivo and in vitro, Alpk1 knockdown downregulated the M1 marker inducible nitric oxide synthase and pro-inflammatory cytokines (tumor necrosis factor-alpha, interleukin-1 beta, interleukin-6). GSEA indicated Alpk1 activates Janus kinase 2 (JAK2) / signal transducer and activator of transcription 3 (STAT3) signaling. Stat3 overexpression reversed the inhibitory effects of Alpk1 knockdown on M1 activation and inflammation.

ALPK1 is highly expressed in epileptic microglia. Silencing Alpk1 alleviates M1-microglial activation and inflammation in epilepsy by inhibiting the JAK2/STAT3 signaling.