Multi-site investigation of gut microbiota in CDKL5 deficiency disorder mouse models: Targeting dysbiosis to improve neurological outcomes.

Cyclin-dependent kinase-like 5 (CDKL5) deficiency disorder (CDD) is a rare neurodevelopmental disorder often associated with gastrointestinal (GI) issues and subclinical immune dysregulation, suggesting a link to the gut microbiota. We analyze the fecal microbiota composition in two CDKL5 knockout (KO) mouse models at postnatal days (P) 25, 32 (youth), and 70 (adulthood), revealing significant microbial imbalances, particularly during juvenile stages. To investigate the role of the intestinal microbiota in CDD and assess causality, we administer antibiotics, which lead to improved visual cortical responses and reduce hyperactivity. Additionally, microglia morphology changes, indicative of altered surveillance and activation states, are reversed. Strikingly, fecal transplantation from CDKL5 KO to wild-type (WT) recipient mice successfully transfers both visual response deficits and hyperactive behavior. These findings show that gut microbiota alterations contribute to the severity of neurological symptoms in CDD, shedding light on the interplay between microbiota, microglia, and neurodevelopmental outcomes.