DS (Down's syndrome) is the most common human aneuploidy associated with mental retardation and early neurodegeneration. Mitochondrial dysfunction has emerged as a crucial factor in the pathogenesis ...of numerous neurological disorders including DS, but the cause of mitochondrial damage remains elusive. In the present study, we identified new molecular events involved in mitochondrial dysfunction which could play a role in DS pathogenesis. We analysed mitochondrial respiratory chain function in DS-HSFs (Down's syndrome human foetal skin fibroblasts; human foetal skin fibroblasts with chromosome 21 trisomy) and found a selective deficit in the catalytic efficiency of mitochondrial complex I. The complex I deficit was associated with a decrease in cAMP-dependent phosphorylation of the 18 kDa subunit of the complex, due to a decrease in PKA (protein kinase A) activity related to reduced basal levels of cAMP. Consistently, exposure of DS-HSFs to db-cAMP (dibutyryl-cAMP), a membrane-permeable cAMP analogue, stimulated PKA activity and consequently rescued the deficit of both the cAMP-dependent phosphorylation and the catalytic activity of complex I; conversely H89, a specific PKA inhibitor, suppressed these cAMP-dependent activations. Furthermore, in the present paper we report a 3-fold increase in cellular levels of ROS (reactive oxygen species), in particular superoxide anion, mainly produced by DS-HSF mitochondria. ROS accumulation was prevented by db-cAMP-dependent activation of complex I, suggesting its involvement in ROS production. Taken together, the results of the present study suggest that the drastic decrease in basal cAMP levels observed in DS-HSFs participates in the complex I deficit and overproduction of ROS by DS-HSF mitochondria.
A critical role for mitochondrial dysfunction has been proposed in the pathogenesis of Down's syndrome (DS), a human multifactorial disorder caused by trisomy of chromosome 21, associated with mental ...retardation and early neurodegeneration. Previous studies from our group demonstrated in DS cells a decreased capacity of the mitochondrial ATP production system and overproduction of reactive oxygen species (ROS) in mitochondria. In this study we have tested the potential of epigallocatechin-3-gallate (EGCG) - a natural polyphenol component of green tea - to counteract the mitochondrial energy deficit found in DS cells. We found that EGCG, incubated with cultured lymphoblasts and fibroblasts from DS subjects, rescued mitochondrial complex I and ATP synthase catalytic activities, restored oxidative phosphorylation efficiency and counteracted oxidative stress. These effects were associated with EGCG-induced promotion of PKA activity, related to increased cellular levels of cAMP and PKA-dependent phosphorylation of the NDUFS4 subunit of complex I. In addition, EGCG strongly promoted mitochondrial biogenesis in DS cells, as associated with increase in Sirt1-dependent PGC-1α deacetylation, NRF-1 and T-FAM protein levels and mitochondrial DNA content. In conclusion, this study shows that EGCG is a promoting effector of oxidative phosphorylation and mitochondrial biogenesis in DS cells, acting through modulation of the cAMP/PKA- and sirtuin-dependent pathways. EGCG treatment promises thus to be a therapeutic approach to counteract mitochondrial energy deficit and oxidative stress in DS.
Rett syndrome (RTT) is a pervasive neurodevelopmental disorder mainly caused by mutations in the X-linked MECP2 gene associated with severe intellectual disability, movement disorders, and ...autistic-like behaviors. Its pathogenesis remains mostly not understood and no effective therapy is available. High circulating levels of oxidative stress markers in patients and the occurrence of oxidative brain damage in MeCP2-deficient mouse models suggest the involvement of oxidative stress in RTT pathogenesis. However, the molecular mechanism and the origin of the oxidative stress have not been elucidated. Here we demonstrate that a redox imbalance arises from aberrant mitochondrial functionality in the brain of MeCP2-308 heterozygous female mice, a condition that more closely recapitulates that of RTT patients. The marked increase in the rate of hydrogen peroxide generation in the brain of RTT mice seems mainly produced by the dysfunctional complex II of the mitochondrial respiratory chain. In addition, both membrane potential generation and mitochondrial ATP synthesis are decreased in RTT mouse brains when succinate, the complex II respiratory substrate, is used as an energy source. Respiratory chain impairment is brain area specific, owing to a decrease in either cAMP-dependent phosphorylation or protein levels of specific complex subunits. Further, we investigated whether the treatment of RTT mice with the bacterial protein CNF1, previously reported to ameliorate the neurobehavioral phenotype and brain bioenergetic markers in an RTT mouse model, exerts specific effects on brain mitochondrial function and consequently on hydrogen peroxide production. In RTT brains treated with CNF1, we observed the reactivation of respiratory chain complexes, the rescue of mitochondrial functionality, and the prevention of brain hydrogen peroxide overproduction. These results provide definitive evidence of mitochondrial reactive oxygen species overproduction in RTT mouse brain and highlight CNF1 efficacy in counteracting RTT-related mitochondrial defects.
•The origin of oxidative stress in Rett syndrome (RTT) was studied.•Impaired mitochondrial complex II induces H2O2 overproduction in RTT mouse brain.•Reactivation of mitochondrial respiratory chain by CNF1 prevented H2O2 production.•Drugs targeting brain mitochondria functionality could be considered for RTT therapy.
Children and adolescents with neurodevelopmental disorders generally show adaptive, cognitive and motor skills impairments associated with behavioral problems, i.e., alterations in attention, anxiety ...and stress regulation, emotional and social relationships, which strongly limit their quality of life. This narrative review aims at providing a critical overview of the current knowledge in the field of serious games (SGs), known as digital instructional interactive videogames, applied to neurodevelopmental disorders. Indeed, a growing number of studies is drawing attention to SGs as innovative and promising interventions in managing neurobehavioral and cognitive disturbs in children with neurodevelopmental disorders. Accordingly, we provide a literature overview of the current evidence regarding the actions and the effects of SGs. In addition, we describe neurobehavioral alterations occurring in some specific neurodevelopmental disorders for which a possible therapeutic use of SGs has been suggested. Finally, we discuss findings obtained in clinical trials using SGs as digital therapeutics in neurodevelopment disorders and suggest new directions and hypotheses for future studies to bridge the gaps between clinical research and clinical practice.
•Neurodevelopmental disorders have impairment in emotional, social and cognitive skills.•Serious games (SGs) are designed for therapeutic purpose not for pure entertainment.•SGs development for digital therapeutic purpose in children requires a multimodal approach.•SGs is proposed as non-pharmacological-assisted therapy for behavioral disorder in children.•Randomized controlled trials are necessary to validate a SG efficacy in neurobehavior.
Metformin is the most common anti-diabetic drug and a promising therapy for disorders beyond diabetes, including Rett syndrome (RTT), a rare neurologic disease characterized by severe intellectual ...disability. A 10-day-long treatment rescued aberrant mitochondrial activity and restrained oxidative stress in a female RTT mouse model. However, this treatment regimen did not improve the phenotype of RTT mice. In the present study, we demonstrate that a 4-month-long treatment with metformin (150 mg/Kg/day, delivered in drinking bottles) provides a selective normalization of cognitive flexibility defects in RTT female mice at an advanced stage of disease, but it does not affect their impaired general health status and abnormal motor skills. The 4-month-long treatment also rescues the reduced activity of mitochondrial respiratory chain complex activities, the defective brain ATP production and levels as well as the increased production of reactive oxidizing species in the whole blood of RTT mice. A significant boost of PGC-1α-dependent pathways related to mitochondrial biogenesis and antioxidant defense occurs in the brain of RTT mice that received the metformin treatment. Further studies will have to verify whether these effects may underlie its long-lasting beneficial effects on brain energy metabolism.
•Metformin normalizes flexible responses for new external cues in Rett syndrome mice.•A rescue of Rett brain mitochondrial defects persists after chronic Met treatment.•Oxidative imbalance is restored after chronic Met treatment in Rett mouse blood.•Modulation of PGC-1α dependent pathways may explain Met beneficial effects for Rett.
Existing evidence about HIV and SARS-CoV-2 co-infection has, so far, yield conflicting results. Methods: This is a cohort, single center, clinical study aimed at identifying possible characteristics ...of PLWH that could correlate with the risk of acquiring SARS-CoV-2 and would influence the outcome. 155 cases of SARS-CoV-2 infection were compared with 307 PLWH who tested negative. No variable was associated with an increased risk of infection. SARS-CoV-2 PLWH were completely asymptomatic in 20.6% of cases. Factors associated with severe COVID-19 were age (P=0.001), diabetes (P=0.009) hypertension (P=0.004), cardiovascular disease (P=0.001) or an increasing number of chronic co-morbidities (P=0.002); only the first two variables retained statistical significance in a multivariable model. Only older age and a lower CD4 count were statistically associated with death in the multivariate model. Sixteen PLWH not included in the analysis were infected by SARS-Cov-2 after vaccination. In 4 cases the infection was completely asymptomatic, while in the remaining 12 cases the infection was mild and resembled a flu-like syndrome. Conclusions: No baseline characteristic defines patients at greater risk of SARS-CoV-2 infection. Older age and the presence of multi-comorbidities are risk factors for a severe clinical course. Lower CD4 counts correlate with a fatal outcome.
Dual treatments could help clinicians to avoid drawbacks and toxicities due to the nucleosidic backbone, while maintaining the efficacy and convenience of robust combination antiretroviral therapy ...(cART). We explored the combination of rilpivirine plus boosted darunavir (DRV) as an option when switching from standard cART in patients who are virologically suppressed. In this randomized, open-label, proof-of-concept, noninferiority trial, we recruited patients aged 18 years or older with chronic HIV-1 infection and on a stable, effective (>6 months) protease inhibitor-based cART including a nucleosidic backbone. The primary endpoint was noninferiority of the virological response between treatment groups, according to FDA snapshot approach. Sixty patients were randomly allocated to dual treatment with rilpivirine plus boosted DRV or to continue their ongoing triple treatment. Noninferiority was shown at the prespecified level of -12% both at 24 and 48 weeks. At week 24, 100% of patients in the dual arm presented a blood HIV-RNA level <50 copies per milliliter compared with 90.1% in the triple drug arm (difference 9.9%, 95% CI: -0.7 to 20.7), whereas, at 48 weeks, the same proportions were 96.7% and 93.4%, respectively (difference 3.3%, 95% CI: -7.15 to 13.5). The mean change in CD4 cell count from baseline was 6.0 cells per microliter (SD, 184) for dual treatment and 16.5 cells per microliter (SD, 142) for triple treatment. A relevant decrement in CD838HLADR cells was observed in both arms. The reduction was, however, significantly more pronounced in the dual-therapy arm. At week 48, the CD838HLADR cell count was 3.4% (SD, 2.2) in the dual-therapy arm and 5.2% (SD, 3.1) in the triple arm (P = 0.018). None of the patients developed severe adverse events nor had to stop treatment because of adverse events or presented grade 3-4 laboratory abnormalities. A greater reduction of bone stiffness (-2.25; SD, 7.1) was observed in patients randomized to continue triple therapy compared with patients switched to dual therapy (-0.32; SD, 8.8). Finally, baseline HIV-DNA content directly correlated with pre-cART viral load of patients (P = 0.021), but not with time on cART or time with HIV-RNA below 50 copies per milliliter. Independently of the study arm, patients with a n HIV-RNA level constantly above 3 copies per milliliter or showing viral blips had baseline HIV-DNA levels significantly higher (64,656 copies per 10 cells; SD, 93057) compared with patients who constantly presented a HIV-RNA level below the detection limit of 3 copies per milliliter (14,457 copies per 10 cells; SD, 14098) (P = 0.001). A rilpivirine-boosted plus ritonavir-boosted DRV therapy was not inferior over 48 weeks to a standard boosted protease inhibitor-based triple cART. The dual therapy did not negatively affect lipid profile and renal function and was more friendly on bone metabolism. This approach constitutes an alternative for patients experiencing nucleoside reverse transcriptase inhibitor-related toxicities.
Mutations in the X-linked cyclin-dependent kinase-like 5 (CDKL5) gene cause CDKL5 Deficiency Disorder (CDD), a rare neurodevelopmental syndrome characterized by severe behavioural and physiological ...symptoms. No cure is available for CDD. CDKL5 is a kinase that is abundantly expressed in the brain and plays a critical role in neurodevelopmental processes, such as neuronal morphogenesis and plasticity. This study provides the first characterization of the neurobehavioural phenotype of 1 year old Cdkl5-null mice and demonstrates that stimulation of the serotonin receptor 7 (5-HT7R) with the agonist molecule LP-211 (0.25 mg/kg once/day for 7 days) partially rescues the abnormal phenotype and brain molecular alterations in Cdkl5-null male mice. In particular, LP-211 treatment completely normalizes the prepulse inhibition defects observed in Cdkl5-null mice and, at a molecular level, restores the abnormal cortical phosphorylation of rpS6, a downstream target of mTOR and S6 kinase, which plays a direct role in regulating protein synthesis. Moreover, we demonstrate for the first time that mitochondria show prominent functional abnormalities in Cdkl5-null mouse brains that can be restored by pharmacological stimulation of brain 5-HT7R.
•Characterization of behavioural phenotype in fully symptomatic Cdkl5-null mice.•The 5HT7R agonist LP-211 normalizes prepulse inhibition defects in Cdkl5-null mice.•LP-211 treatment rescues brain mitochondrial dysfunction in Cdkl5-null mice.•The abnormal phosphorylation of rpS6 in Cdkl5-null cortex is restored by LP-211.
Oxygen free radical burst is a prominent early event in the pathogenesis of Alzheimer’s disease (AD). Posttranslational modifications of Tau protein, primarily hyper-phosphorylation and truncation, ...are indicated as critical mediators of AD pathology. This finding is confirmed by the high levels of oxidative stress markers and by the increased susceptibility to oxygen radicals found in cultured neurons and in brains from transgenic animal models expressing toxic Tau forms, in concomitance with a dramatic reduction in their viability/survival. Here, we collect the latest progress in research focused on the reciprocal and dynamic interplay between oxygen radicals and pathological Tau, discussing how these harmful species cooperate and/or synergize in the progression of AD. In this context, a better understanding of the role of oxidative stress in determining Tau pathology, and vice versa, primarily could be able to define novel biomarkers of early stages of human tauopathies, including AD, and then to develop therapeutic strategies aimed at attenuating, halting, or reversing disease progression.
Abstract Rho GTPases are molecules critically involved in neuronal plasticity and cognition. We have previously reported that modulation of brain Rho GTPases by the bacterial toxin CNF1 rescues the ...neurobehavioral phenotype in MeCP2-308 male mice, a model of Rett syndrome (RTT). RTT is a rare X-linked neurodevelopmental disorder and a genetic cause of intellectual disability, for which no effective therapy is available. Mitochondrial dysfunction has been proposed to be involved in the mechanism of the disease pathogenesis. Here we demonstrate that modulation of Rho GTPases by CNF1 rescues the reduced mitochondrial ATP production via oxidative phosphorylation in the brain of MeCP2-308 heterozygous female mice, the condition which more closely recapitulates that of RTT patients. In RTT mouse brain, CNF1 also restores the alterations in the activity of the mitochondrial respiratory chain (MRC) complexes and of ATP synthase, the molecular machinery responsible for the majority of cell energy production. Such effects were achieved through the upregulation of the protein content of those MRC complexes subunits, which were defective in RTT mouse brain. Restored mitochondrial functionality was accompanied by the rescue of deficits in cognitive function (spatial reference memory in the Barnes maze), synaptic plasticity (long-term potentiation) and Tyr1472 phosphorylation of GluN2B, which was abnormally enhanced in the hippocampus of RTT mice. Present findings bring into light previously unknown functional mitochondrial alterations in the brain of female mice modeling RTT and provide the first evidence that RTT brain mitochondrial dysfunction can be rescued by modulation of Rho GTPases.
PDF
