Effect of stress on learning and motivation-relevance to autism spectrum disorder

Complement C4-deficient mice have a high mortality rate during PTZ-induced epileptic seizures, which correlates with cognitive problems and the deficiency in the expression of Egr1 and other immediate early genes

Complement system plays an important role in the immune defense against pathogens; however, recent studies demonstrated an important role of complement subunits C1q, C4, and C3 in normal functions of the central nervous system (CNS) such as non-functional synapse elimination (synapse pruning), and during various neurologic pathologies. Humans have two forms of C4 protein encoded by C4A and C4B genes that share 99.5% homology, while mice have only one C4B gene that is functionally active in the complement cascade. Overexpression of the human C4A gene was shown to contribute to the development of schizophrenia by mediating extensive synapse pruning through the activation C1q-C4-C3 pathway, while C4B deficiency or low levels of C4B expression were shown to relate to the development of schizophrenia and autism spectrum disorders possibly via other mechanisms not related to synapse elimination. To investigate the potential role of C4B in neuronal functions not related to synapse pruning, we compared wildtype (WT) mice with C3- and C4B- deficient animals for their susceptibility to pentylenetetrazole (PTZ)- induced epileptic seizures. We found that C4B (but not C3)-deficient mice were highly susceptible to convulsant and subconvulsant doses of PTZ when compared to WT controls. Further gene expression analysis revealed that in contrast to WT or C3-deficient animals, C4B-deficient mice failed to upregulate expressions of multiple immediate early genes (IEGs) Egrs1-4, c-Fos, c-Jus, FosB, Npas4, and Nur77 during epileptic seizures. Moreover, C4B-deficient mice had low levels of baseline expression of Egr1 on mRNA and protein levels, which was correlated with the cognitive problems of these animals. C4-deficient animals also failed to upregulate several genes downstream of IEGs such as BDNF and pro-inflammatory cytokines IL-1β, IL-6, and TNF. Taken together, our study demonstrates a new role of C4B in the regulation of expression of IEGs and their downstream targets during CNS insults such as epileptic seizures.

Epidemiological Study of Autism Spectrum Disorders in Greece for 2021: Nationwide Prevalence in 2–17-Year-Old Children and Regional Disparities

This study estimated the crude prevalence of autism spectrum disorders (ASD) in Greece in 2021. A retrospective study was conducted for 2021 using data provided for research purposes for the first time by the Greek National Health Service Organization for Healthcare Services Provision (EOPYY) related to the ICD-10 diagnosis codes F84.0–F84.9 (ASD). Treatments were categorized by gender, age, and location. Statistical analysis was performed using the open-source software R. In total, 15,706 children aged 2–17 years were registered with ASD: 12,380 boys and 3326 girls. In total, 6,117,910 therapies were prescribed: 4,844,173 for boys and 1,273,737 for girls. Boys are estimated to be diagnosed 3.5 times more often than girls. On average, approximately 390 treatments are prescribed per person per year for both sexes. The annual prevalence is estimated at 0.94%, ranging from 0.42% to 1.44% depending on geographic region. Our findings provide evidence-based data for the planning of policies regarding health, education, and employment for people with ASD. The number of children and treatments makes ASD a public health concern to support children and their families and ensure equal participation in all aspects of society.

Genomics as a Clinical Decision Support Tool: Successful Proof of Concept for Improved ASD Outcomes

Considerable evidence is emerging that Autism Spectrum Disorder (ASD) is most often triggered by a range of different genetic variants that interact with environmental factors such as exposures to toxicants and changes to the food supply. Up to 80% of genetic variations that contribute to ASD found to date are neither extremely rare nor classified as pathogenic. Rather, they are less common single nucleotide polymorphisms (SNPs), found in 1-15% or more of the population, that by themselves are not disease-causing. These genomic variants contribute to ASD by interacting with each other, along with nutritional and environmental factors. Examples of pathways affected or triggered include those related to brain inflammation, mitochondrial dysfunction, neuronal connectivity, synapse formation, impaired detoxification, methylation, and neurotransmitter-related effects. This article presents information on four case study patients that are part of a larger ongoing pilot study. A genomic clinical decision support (CDS) tool that specifically focuses on variants and pathways that have been associated with neurodevelopmental disorders was used in this pilot study to help develop a targeted, personalized prevention and intervention strategy for each child. In addition to an individual's genetic makeup, each patient's personal history, diet, and environmental factors were considered. The CDS tool also looked at genomic SNPs associated with secondary comorbid ASD conditions including attention deficit hyperactivity disorder (ADHD), obsessive-compulsive disorder (OCD), anxiety, and pediatric autoimmune neuropsychiatric disorder associated with streptococcal infections/pediatric acute-onset neuropsychiatric syndrome (PANDAS/PANS). The interpreted genomics tool helped the treating clinician identify and develop personalized, genomically targeted treatment plans. Utilization of this treatment approach was associated with significant improvements in socialization and verbal skills, academic milestones and intelligence quotient (IQ), and overall increased ability to function in these children, as measured by autism treatment evaluation checklist (ATEC) scores and parent interviews.

Anti-inflammatory effects of natural flavonoid diosmetin in IL-4 and LPS-induced macrophage activation and atopic dermatitis model

Diosmetin, a citrus flavonoid, has a variety of therapeutic properties such as antibacterial, anti-inflammatory and antioxidant effects. However, the effect of diosmetin on atopic dermatitis (AD) development has not been reported. This study thus aims to investigate whether diosmetin possesses inhibitory effects on AD development. A dinitrochlorobenzene (DNCB)-induced AD mouse model was used to evaluate the effects of diosmetin on AD development. Treatment with diosmetin significantly reduced the dermatitis score, thickness of epidermis and dermis and number of mast cells in comparison with the untreated group. Furthermore, immunohistochemical analysis using an anti-F4/80 antibody demonstrated that diosmetin significantly suppressed macrophage infiltration into the AD lesion. It was observed that the levels of pro-inflammatory cytokines (TNF-α, IL-4 and IL-1β) in skin lesion decreased in response to treatment with diosmetin. In addition, the anti-inflammatory effect of diosmetin was evaluated in LPS- or IL-4-induced a mouse macrophage cell line (raw 264.7). Diosmetin inhibited the production of nitric oxide and decreased the expression of inducible nitric oxide synthase (iNOS). Diosmetin not only suppressed the phosphorylation of MAP kinase (ERK 1/2, p38 and JNK) but the activation of JAK/STAT signaling. The mRNA analysis demonstrated that diosmetin also reduced the level of inflammatory cytokines such as IL-1β and IL-6. Collectively, these results demonstrate that diosmetin exhibits the inhibitory effect on AD, suggesting that diosmetin may be a potential therapeutic agent for this atopic disorder.

Reprogramming of the Immune System by Stress and Faulty Hormonal Imprinting

PURPOSE

Hormonal imprinting is taking place perinatally at the first encounter between the developing hormone receptors and their target hormones. However, in this crucial period when the developmental window for physiological imprinting is open, other molecules, such as synthetic hormones and endocrine disruptors can bind to the receptors, leading to faulty imprinting with life-long consequences, especially to the immune system. This review presents the factors of stress and faulty hormonal imprinting that lead to reprogramming of the immune system.

METHODS

Relevant publications from Pubmed since 1990 were reviewed and synthesized.

FINDINGS

The developing immune system is rather sensitive to hormonal effects. Faulty hormonal imprinting is able to reprogram the original developmental program present in a given cell, with lifelong consequences, manifested in alteration of hormone binding by receptors, susceptibility to certain (non-infectious) diseases, and triggering of other diseases. As stress mobilizes the hypothalamic-pituitary-adrenal axis if it occurred during gestation or perinatally, it could lead to faulty hormonal imprinting in the immune system, manifested later as allergic and autoimmune diseases or weakness of normal immune defenses. Hormonal imprinting is an epigenetic process and is carried to the offspring without alteration of DNA base sequences. This means that any form of early-life stress alone or in association with hormonal imprinting could be associated with the developmental origin of health and disease (DOHaD). As puberty is also a period of reprogramming, stress or faulty imprinting can change the original (developmental) program, also with life-long consequences.

IMPLICATIONS

Considering the continuous differentiation of immune cells (from blast-cells) during the whole life, there is a possibility of late-imprinting or stress-activated reprogramming in the immune system at any periods of life, with later pathogenetic consequences.

Mast Cells, Stress, Fear and Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is a developmental condition characterized by impaired communication and obsessive behavior that affects 1 in 59 children. ASD is expected to affect 1 in about 40 children by 2020, but there is still no distinct pathogenesis or effective treatments. Prenatal stress has been associated with higher risk of developing ASD in the offspring. Moreover, children with ASD cannot handle anxiety and respond disproportionately even to otherwise benign triggers. Stress and environmental stimuli trigger the unique immune cells, mast cells, which could then trigger microglia leading to abnormal synaptic pruning and dysfunctional neuronal connectivity. This process could alter the "fear threshold" in the amygdala and lead to an exaggerated "fight-or-flight" reaction. The combination of corticotropin-releasing hormone (CRH), secreted under stress, together with environmental stimuli could be major contributors to the pathogenesis of ASD. Recognizing these associations and preventing stimulation of mast cells and/or microglia could greatly benefit ASD patients.