How Robust is the Evidence for a Role of Oxidative Stress in Autism Spectrum Disorders and Intellectual Disabilities?

A Novel Mutation in the MAP7D3 Gene in Two Siblings with Severe Intellectual Disability and Autistic Traits: Concurrent Assessment of BDNF Functional Polymorphism, X-Inactivation and Oxidative Stress to Explain Disease Severity

Intellectual disabilities (ID) and autism spectrum disorders (ASD) are characterized by extreme genetic and phenotypic heterogeneity. However, understanding this heterogeneity is difficult due to the intricate interplay among multiple interconnected genes, epigenetic factors, oxidative stress, and environmental factors. Employing next-generation sequencing (NGS), we revealed the genetic cause of ID and autistic traits in two patients from a consanguineous family followed by segregation analysis. Furthermore, in silico prediction methods and 3D modeling were conducted to predict the effect of the variants. To establish genotype-phenotype correlation, X-chromosome inactivation using Methylation-specific PCR and oxidative stress markers were also investigated. By analyzing the NGS data of the two patients, we identified a novel frameshift mutation c.2174_2177del (p.Thr725MetfsTer2) in the MAP7D3 gene inherited from their mother along with the functional BDNF Val66Met polymorphism inherited from their father. The 3D modeling demonstrated that the p.Thr725MetfsTer2 variant led to the loss of the C-terminal tail of the MAP7D3 protein. This change could destabilize its structure and impact kinesin-1's binding to microtubules via an allosteric effect. Moreover, the analysis of oxidative stress biomarkers revealed an elevated oxidative stress in the two patients compared to the controls. To the best of our knowledge, this is the first report describing severe ID and autistic traits in familial cases with novel frameshift mutation c.2174_2177del in the MAP7D3 gene co-occurring with the functional polymorphism Val66M in the BDNF gene. Besides, our study underlines the importance of investigating combined genetic variations, X-chromosome inactivation (XCI) patterns, and oxidative stress markers for a better understanding of ID and autism etiology.

DNA damage in dementia: Evidence from patients affected by severe Chronic Obstructive Pulmonary Disease (COPD) and meta-analysis of most recent literature

Oxidative stress that leads to oxidatively damaged DNA, plays a crucial role in chronic obstructive pulmonary disease (COPD) as well as in the onset of neurodegenerative diseases. The consequent genomic instability is the first neuropathological event found in the preclinical phase of cognitive impairment (CI), and the level of DNA damage is closely related to the degree of dementia. Since CI has been associated with COPD, we investigated the extent of DNA damage in isolated lymphocytes with the Comet assay, in a group of severe COPD patients with cognitive function measured by the Mini-Mental State Examination (MMSE). An increase in DNA damage was observed in COPD patients with dementia (MMSE≤24), although the difference was only borderline (22.4 ± 6.9 vs. 18.5 ± 7.1; p = 0.055). Meta-analysis, including the results of the current study, confirmed that patients with MMSE≤ 24 showed higher level of DNA damage than patients with MMSE> 24. We observed a significant reduction (p < 0.001) in the MMSE score in patients with cognitive decline in areas I (Orientation), III (Attention and Calculus) and V (Language). Only the temporal orientation category in area I was also associated with the level of oxidative damage, with higher levels of MDA (p < 0.01) and DNA damage (p < 0.03). Patients with the lowest temporal orientation score had a 12% higher mean DNA damage (Odds Ratio=1.12; 95% confidence interval (95%CI) 1.01-1.25; p < 0.036). Temporal orientation is a component of most screening tests for the diagnosis of cognitive impairment, on the bases that disorientation is a common factor in dementia. Present results show that each component of cognitive decline can have a different etiopathogenesis and clinical relevance. A more thorough assessment of the cognitive functions of patients starting COPD rehabilitation, together with the assessment of DNA and the level of oxidative stress, can provide essential information to adapt and customize the rehabilitation project.

Guggulsterone Mediated JAK/STAT and PPAR-Gamma Modulation Prevents Neurobehavioral and Neurochemical Abnormalities in Propionic Acid-Induced Experimental Model of Autism

Autism spectrum disorder is a neurodevelopmental disorder marked by repetitive behaviour, challenges in verbal and non-verbal communication, poor socio-emotional health, and cognitive impairment. An increased level of signal transducer and activator of transcription 3 (STAT3) and a decreased level of peroxisome proliferator-activated receptor (PPAR) gamma have been linked to autism pathogenesis. Guggulsterone (GST) has a neuroprotective effect on autistic conditions by modulating these signalling pathways. Consequently, the primary objective of this study was to examine potential neuroprotective properties of GST by modulating JAK/STAT and PPAR-gamma levels in intracerebroventricular propionic acid (ICV PPA) induced experimental model of autism in adult rats. In this study, the first 11 days of ICV-PPA injections in rats resulted in autism-like behavioural, neurochemical, morphological, and histopathological changes. The above modifications were also observed in various biological samples, including brain homogenate, CSF, and blood plasma. GST was also observed to improve autism-like behavioural impairments in autistic rats treated with PPA, including locomotion, neuromuscular coordination, depression-like behaviour, spatial memory, cognition, and body weight. Prolonged GST treatment also restored neurochemical deficits in a dose-dependent manner. Chronic PPA administration increased STAT3 and decreased PPAR gamma in autistic rat brain, CSF, and blood plasma samples, which were reversed by GST. GST also restored the gross and histopathological alterations in PPA-treated rat brains. Our results indicate the neuroprotective effects of GST in preventing autism-related behavioural and neurochemical alterations.

Glutathione S-Transferase Polymorphisms and Clinical Characteristics in Autism Spectrum Disorders

Background: Autism spectrum disorders (ASD) are a heterogeneous group of developmental disorders, with different levels of symptoms, functioning, and comorbidities. Recent findings suggested that oxidative stress and genetic variability in glutathione S-transferases (GSTs) might increase the risk of ASD development. We aimed to determine whether GST polymorphisms influence the severity of symptoms as well as the cognitive and adaptive abilities in children with ASD. Methods: The sample included 113 ASD cases. All participants were genotyped for GSTA1, GSTM1, GSTT1, and GSTP1 polymorphisms. The clinical characteristics were determined with Autism Diagnostic Interview-Revised (ADI-R) in all of the participants. In non-verbal participants, we explored the adaptive functioning using the Vineland Adaptive Behavior Scale II, while in verbal participants, we used the Wechsler Abbreviated Scale of Intelligence (WASI). Results: It was shown that the GSTA1 * CC genotype was a predictor of a lower non-verbal communication impairment as well as of a lower chance of having seizures during life. GSTM1-active genotype predicted a higher adaptive functioning. The predictive effect of GSTA1, GSTM1, and GSTT1 genotype was moderated by exposure during pregnancy (maternal smoking and medication). The GSTP1 * IleIle genotype was significantly associated to a better cognitive functioning in children with ASD. Conclusion: Besides the complex gene-environment interaction for the specific risk of developing ASD, there is also a possible complexity of interactions between genetic and environmental factors influencing the level of symptoms and impairment in people with ASD. Detoxification and antioxidant enzymes, such as GSTA1, might contribute to the core of this complexity.