CRISPR/Cas9-mediated neuronal deletion of 5-lipoxygenase alleviates deficits in mouse models of epilepsy

Our previous work reveals a critical role of activation of neuronal Alox5 in exacerbating brain injury post seizures. However, whether neuronal Alox5 impacts the pathological process of epilepsy remains unknown. To prove the feasibility of neuron-specific deletion of Alox5 via CRISPR-Cas9 in the blockade of seizure onset and epileptic progression. Here, we employed a Clustered regularly interspaced short-palindromic repeat-associated proteins 9 system (CRISPR/Cas9) system delivered by adeno-associated virus (AAV) to specifically delete neuronal Alox5 gene in the hippocampus to explore its therapeutic potential in various epilepsy mouse models and possible mechanisms. Neuronal depletion of Alox5 was successfully achieved in the brain. AAV delivery of single guide RNA of Alox5 in hippocampus resulted in reducing seizure severity, delaying epileptic progression and improving epilepsy-associated neuropsychiatric comorbidities especially anxiety, cognitive deficit and autistic-like behaviors in pilocarpine- and kainic acid-induced temporal lobe epilepsy (TLE) models. In addition, neuronal Alox5 deletion also reversed neuron loss, neurodegeneration, astrogliosis and mossy fiber sprouting in TLE model. Moreover, a battery of tests including analysis of routine blood test, hepatic function, renal function, routine urine test and inflammatory factors demonstrated no noticeable toxic effect, suggesting that Alox5 deletion possesses the satisfactory biosafety. Mechanistically, the anti-epileptic effect of Alox5 deletion might be associated with reduction of glutamate level to restore excitatory/inhibitory balance by reducing CAMKII-mediated phosphorylation of Syn ISer603. Our findings showed the translational potential of AAV-mediated delivery of CRISPR-Cas9 system including neuronal Alox5 gene for an alternative promising therapeutic approach to treat epilepsy.