CDKL5 deficiency disorder (CDD), a rare and severe neurodevelopmental disease caused by mutations in the X-linked CDKL5 gene, is characterized by early-onset epilepsy, intellectual disability, and autistic features. Although pharmacotherapy has shown promise in the CDD mouse model, safe and effective clinical treatments are still far off. Recently, we found increased microglial activation in the brain of a mouse model of CDD, the Cdkl5 KO mouse, suggesting that a neuroinflammatory state, known to be involved in brain maturation and neuronal dysfunctions, may contribute to the pathophysiology of CDD. The present study aims to evaluate the possible beneficial effect of treatment with luteolin, a natural flavonoid known to have anti-inflammatory and neuroprotective activities, on brain development and behavior in a heterozygous Cdkl5 (+/−) female mouse, the mouse model of CDD that best resembles the genetic clinical condition. We found that inhibition of neuroinflammation by chronic luteolin treatment ameliorates motor stereotypies, hyperactive profile and memory ability in Cdkl5 +/− mice. Luteolin treatment also increases hippocampal neurogenesis and improves dendritic spine maturation and dendritic arborization of hippocampal and cortical neurons. These findings show that microglia overactivation exerts a harmful action in the Cdkl5 +/− brain, suggesting that treatments aimed at counteracting the neuroinflammatory process should be considered as a promising adjuvant therapy for CDD.

CDKL5 (cyclin-dependent kinase-like 5) deficiency disorder (CDD) is a severe neurodevelopmental disease that mostly affects girls, who are heterozygous for mutations in the X-linked CDKL5 gene. Mutations in the CDKL5 gene lead to a lack of CDKL5 protein expression or function and cause numerous clinical features, including early-onset seizures, marked hypotonia, autistic features, gastrointestinal problems, and severe neurodevelopmental impairment. Mouse models of CDD recapitulate several aspects of CDD symptomology, including cognitive impairments, motor deficits, and autistic-like features, and have been useful to dissect the role of CDKL5 in brain development and function. However, our current knowledge of the function of CDKL5 in other organs/tissues besides the brain is still quite limited, reducing the possibility of broad-spectrum interventions. Here, for the first time, we report the presence of cardiac function/structure alterations in heterozygous Cdkl5 +/− female mice. We found a prolonged QT interval (corrected for the heart rate, QTc) and increased heart rate in Cdkl5 +/− mice. These changes correlate with a marked decrease in parasympathetic activity to the heart and in the expression of the Scn5a and Hcn4 voltage-gated channels. Interestingly, Cdkl5 +/− hearts showed increased fibrosis, altered gap junction organization and connexin-43 expression, mitochondrial dysfunction, and increased ROS production. Together, these findings not only contribute to our understanding of the role of CDKL5 in heart structure/function but also document a novel preclinical phenotype for future therapeutic investigation.

Cyclin-dependent kinase-like 5 (CDKL5) deficiency disorder (CDD) is a rare neurodevelopmental disease caused by mutations in the X-linked CDKL5 gene. CDD is characterized by a broad spectrum of clinical manifestations, including early-onset refractory epileptic seizures, intellectual disability, hypotonia, visual disturbances, and autism-like features. The Cdkl5 knockout (KO) mouse recapitulates several features of CDD, including autistic-like behavior, impaired learning and memory, and motor stereotypies. These behavioral alterations are accompanied by diminished neuronal maturation and survival, reduced dendritic branching and spine maturation, and marked microglia activation. There is currently no cure or effective treatment to ameliorate the symptoms of the disease. Aerobic exercise is known to exert multiple beneficial effects in the brain, not only by increasing neurogenesis, but also by improving motor and cognitive tasks. To date, no studies have analyzed the effect of physical exercise on the phenotype of a CDD mouse model. In view of the positive effects of voluntary running on the brain of mouse models of various human neurodevelopmental disorders, we sought to determine whether voluntary daily running, sustained over a month, could improve brain development and behavioral defects in Cdkl5 KO mice. Our study showed that long-term voluntary running improved the hyperlocomotion and impulsivity behaviors and memory performance of Cdkl5 KO mice. This is correlated with increased hippocampal neurogenesis, neuronal survival, spine maturation, and inhibition of microglia activation. These behavioral and structural improvements were associated with increased BDNF levels. Given the positive effects of BDNF on brain development and function, the present findings support the positive benefits of exercise as an adjuvant therapy for CDD.

CDKL5 deficiency disorder (CDD), a developmental encephalopathy caused by mutations in the cyclin-dependent kinase-like 5 (CDKL5) gene, is characterized by a complex and severe clinical picture, including early-onset epilepsy and cognitive, motor, visual, and gastrointestinal disturbances. This disease still lacks a medical treatment to mitigate, or reverse, its course and improve the patient’s quality of life. Although CDD is primarily a genetic brain disorder, some evidence indicates systemic abnormalities, such as the presence of a redox imbalance in the plasma and skin fibroblasts from CDD patients and in the cardiac myocytes of a mouse model of CDD. In order to shed light on the role of oxidative stress in the CDD pathophysiology, in this study, we aimed to investigate the therapeutic potential of Coenzyme Q10 (CoQ10), which is known to be a powerful antioxidant, using in vitro and in vivo models of CDD. We found that CoQ10 supplementation not only reduces levels of reactive oxygen species (ROS) and normalizes glutathione balance but also restores the levels of markers of DNA damage (γ-H2AX) and senescence (lamin B1), restoring cellular proliferation and improving cellular survival in a human neuronal model of CDD. Importantly, oral supplementation with CoQ10 exerts a protective role toward lipid peroxidation and DNA damage in the heart of a murine model of CDD, the Cdkl5 (+/−) female mouse. Our results highlight the therapeutic potential of the antioxidant supplement CoQ10 in counteracting the detrimental oxidative stress induced by CDKL5 deficiency.

CDKL5 deficiency disorder (CDD), a developmental encephalopathy caused by mutations in the cyclin-dependent kinase-like 5 (CDKL5) gene, is characterized by a complex and severe clinical picture, including early-onset epilepsy, cognitive, motor, visual, and gastrointestinal disturbances. This disease still lacks a medical treatment to mitigate, or reverse, its course, and improve the patient’s quality of life. Although CDD is primarily a genetic brain disorder, some evidence in-dicates systemic abnormalities, such as the presence of a redox imbalance in plasma and skin fi-broblasts from CDD patients and in cardiac myocytes of a mouse model of CDD. In order to shed light on the role of oxidative stress in the CDD pathophysiology, in this study we aimed to in-vestigate the therapeutic potential of Coenzyme Q10 (CoQ10), which is known to be a powerful antioxidant, using in vitro and in vivo models of CDD. We found that CoQ10 supplementation not only reduces levels of Reactive Oxygen Species (ROS) and normalizes glutathione balance, but also restores the levels of markers of DNA damage (γ-H2AX) and senescence (lamin B1), significantly improving cellular proliferation and survival in a human neuronal model of CDD. Importantly, oral supplementation with CoQ10 exerts a protective role toward lipid peroxidation and DNA damage in the heart of a murine model of CDD, the Cdkl5 (+/−) female mouse. Our results highlight the therapeutic potential of the antioxidant supplement CoQ10 in counteracting the detrimental oxidative stress induced by CDKL5 deficiency.

Cyclin-dependent kinase-like 5 (CDKL5) deficiency disorder (CDD) is a severe X-linked neurodevelopmental condition characterized by early-onset, intractable epilepsy, motor and cognitive impairment, and autistic-like features. Although constitutive Cdkl5 knockout (KO) models have established the importance of CDKL5 during early brain development, CDKL5’s role in the mature brain remains poorly defined. Here, we employed an inducible, conditional KO model in which Cdkl5 is selectively deleted from forebrain glutamatergic neurons in adult mice to investigate the postdevelopmental functions of CDKL5. Using a total of 48 adult male mice, including Cdkl5^flox/Y(Cre⁺) (n = 30) and Cdkl5^flox/Y(Cre⁻) littermate controls (n = 18), we found that tamoxifen-induced Cdkl5 deletion led to prominent behavioral impairments, including deficits in motor coordination, reduced sociability, and impaired hippocampus-dependent spatial memory, while behavioral features such as hyperactivity and stereotypic jumping, typically present in germline KOs, were absent. Sensory functions, including olfaction and pain perception, were also preserved. At the cellular level, the loss of Cdkl5 resulted in a marked reduction in excitatory synapse density in the cortex and hippocampus, accompanied by increased numbers of immature dendritic spines and decreased mature spines. Neuronal loss in the hippocampal CA1 region and selective microglial activation in the cortex were also observed. These alterations closely resemble those seen in constitutive KO models, underscoring the ongoing requirement for CDKL5 expression in excitatory neurons for maintaining synaptic integrity and neuronal homeostasis in the adult brain. This study underscores the importance of temporally controlled models for investigating the mechanisms underlying CDD pathophysiology in the adult brain.