AbstractBackgroundCDKL5 deficiency disorder (CDD), a severe neurodevelopmental disorder characterized by early onset epilepsy, intellectual disability, and autistic features, is caused by mutations in theCDKL5gene. Evidence in animal models of CDD showed that absence of CDKL5 negatively affects neuronal survival, as well as neuronal maturation and dendritic outgrowth; however, knowledge of the substrates underlying these alterations is still limited. Neuroinflammatory processes are known to contribute to neuronal dysfunction and death. Recent evidence shows a subclinical chronic inflammatory status in plasma from CDD patients. However, to date, it is unknown whether a similar inflammatory status is present in the brain of CDD patients and, if so, whether this plays a causative or exacerbating role in the pathophysiology of CDD.MethodsWe evaluated microglia activation using AIF-1 immunofluorescence, proinflammatory cytokine expression, and signaling in the brain of a mouse model of CDD, theCdkl5KO mouse, which is characterized by an impaired survival of hippocampal neurons that worsens with age. Hippocampal neuron survival was determined by DCX, NeuN, and cleaved caspase-3 immunostaining inCdkl5KO mice treated with luteolin (10 mg/kg), a natural anti-inflammatory flavonoid. Since hippocampal neurons ofCdkl5KO mice exhibit increased susceptibility to excitotoxic stress, we evaluated neuronal survival inCdkl5KO mice injected with NMDA (60 mg/kg) after a 7-day treatment with luteolin.ResultsWe found increased microglial activation in the brain of theCdkl5KO mouse. We found alterations in microglial cell morphology and number, increased levels of AIF-1 and proinflammatory cytokines, and activation of STAT3 signaling. Remarkably, treatment with luteolin recovers microglia alterations as well as neuronal survival and maturation inCdkl5KO mice, and prevents the increase in NMDA-induced cell death in the hippocampus.ConclusionsOur results suggest that neuroinflammatory processes contribute to the pathogenesis of CDD and imply the potential usefulness of luteolin as a treatment option in CDD patients.