Disregulation of Autophagy in the Transgenerational Cc2d1a Mouse Model of Autism

A nonsense CC2D1A variant is associated with congenital anomalies, motor delay, hypotonia, and slight deformities

Background

Autosomal recessive intellectual developmental disorder-3 is caused by homozygous or compound heterozygous mutations in the CC2D1A gene. The disorder is characterized by intellectual disability (ID) and autism spectrum disorder (ASD). To date, 39 patients from 17 families with CC2D1A -related disorders have been reported worldwide, in whom only six pathogenic or likely pathogenic loss-of-function variants and three variants of uncertain significance (VUS) in the CC2D1A gene have been identified in these patients.

Methods

We described a patient with ID from a non-consanguineous Chinese family and whole-exome sequencing (WES) was used to identify the causative gene.

Results

The patient presented with severe ID and ASD, speech impairment, motor delay, hypotonia, slight facial anomalies, and finger deformities. Threatened abortion and abnormal fetal movements occurred during pregnancy with the proband but not his older healthy sister. WES analysis identified a homozygous nonsense variant, c.736C > T (p.Gln246Ter), in the CC2D1A gene. In addition, six novel likely pathogenic CC2D1A variants were identified by a retrospective review of the in-house database.

Conclusions

This study expands the genetic and clinical spectra of CC2D1A-associated disorders, and may aid in increasing awareness of this rare condition. Our findings have provided new insights into the clinical heterogeneity of the disease and further phenotype-genotype correlation, which could help to offer scope for more accurate genetic testing and counseling to affected families.

Identification and Analysis of ZIC-Related Genes in Cerebellum of Autism Spectrum Disorders

Objective

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder with significant genetic heterogeneity. The ZIC gene family can regulate neurodevelopment, especially in the cerebellum, and has been implicated in ASD-like behaviors in mice. We performed bioinformatic analysis to identify the ZIC gene family in the ASD cerebellum.

Methods

We explored the roles of ZIC family genes in ASD by investigating (i) the association of ZIC genes with ASD risk genes from the Simons Foundation Autism Research Initiative (SFARI) database and ZIC genes in the brain regions of the Human Protein Atlas (HPA) database; (ii) co-expressed gene networks of genes positively and negatively correlated with ZIC1, ZIC2, and ZIC3, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, and receiver operating characteristic (ROC) curve analysis of genes in these networks; and (iii) the relationship between ZIC1, ZIC2, ZIC3, and their related genes with cerebellar immune cells and stromal cells in ASD patients.

Results

(i) ZIC1, ZIC2, and ZIC3 were associated with neurodevelopmental disorders and risk genes related to ASD in the human cerebellum and (ii) ZIC1, ZIC2, and ZIC3 were highly expressed in the cerebellum, which may play a pathogenic role by affecting neuronal development and the cerebellar internal environment in patients with ASD, including immune cells, astrocytes, and endothelial cells. (iii) OLFM3, SLC27A4, GRB2, TMED1, NR2F1, and STRBP are closely related to ZIC1, ZIC2, and ZIC3 in ASD cerebellum and have good diagnostic accuracy. (iv) ASD mice in the maternal immune activation model demonstrated that Zic3 and Nr2f1 levels were decreased in the immune-activated cerebellum.

Conclusion

Our study supports the role of ZIC1, ZIC2, and ZIC3 in ASD pathogenesis and provides potential targets for early and accurate prediction of ASD.

Metabolome subtyping reveals multi-omics characteristics and biological heterogeneity in major psychiatric disorders

Growing evidence suggests that major psychiatric disorders (MPDs) share common etiologies and pathological processes. However, the diagnosis is currently based on descriptive symptoms, which ignores the underlying pathogenesis and hinders the development of clinical treatments. This highlights the urgency of characterizing molecular biomarkers and establishing objective diagnoses of MPDs. Here, we collected untargeted metabolomics, proteomics and DNA methylation data of 327 patients with MPDs, 131 individuals with genetic high risk and 146 healthy controls to explore the multi-omics characteristics of MPDs. First, differential metabolites (DMs) were identified and we classified MPD patients into 3 subtypes based on DMs. The subtypes showed distinct metabolomics, proteomics and DNA methylation signatures. Specifically, one subtype showed dysregulation of complement and coagulation proteins, while the DNA methylation showed abnormalities in chemical synapses and autophagy. Integrative analysis in metabolic pathways identified the important roles of the citrate cycle, sphingolipid metabolism and amino acid metabolism. Finally, we constructed prediction models based on the metabolites and proteomics that successfully captured the risks of MPD patients. Our study established molecular subtypes of MPDs and elucidated their biological heterogeneity through a multi-omics investigation. These results facilitate the understanding of pathological mechanisms and promote the diagnosis and prevention of MPDs.

Decreased levels of alpha synuclein in families with autism spectrum disorder and relationship between the disease severity

Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental disorders that begin in early childhood. Mutations in α-synuclein (SNCA) gene have been shown to result in the accumulation of α-synuclein, which occurs in many neurodegenerative diseases. Our aim was to determine the changes in the expression profile and protein level of this gene by comparing the autistic children with their healthy siblings, their mothers and healthy controls in order to elucidate the possible contribution of the SNCA gene to the etiology of ASD. 50 autistic patients, their mothers, siblings and 25 healthy controls and their mothers were enrolled to determine SNCA gene expression and serum α-synuclein levels. It was determined that α-synuclein serum levels decreased in the autistic patients. Similarly, it was found that SNCA gene expression and serum α-synuclein levels were significantly decreased in the mothers of the patients. Significant negative correlation was observed between the SNCA gene and protein expression amounts in the 6-8 age of the patients. This family-based study is the first in the literature, with both gene expression and serum levels of α-synuclein. The relationship between ASD severity and α-synuclein level needs to be confirmed in larger-scale studies.

Silymarin, an antioxidant flavonoid, protects the liver from the toxicity of the anticancer drug paclitaxel

One of the biggest factors that negatively affect the cancer treatment plan is the toxic effects of chemotherapeutics on non-target cells and tissues. This information prompted us to investigate the protective effects of silymarin (SL), a hepatoprotective agent, against the hepatotoxic effects of the anticancer drug paclitaxel (PAC). Four groups were formed from 28 rats as control, PAC (2 mg/kg), SL (100 mg/kg) and PAC + SL (combination of PAC with SL). After completing the experimental procedures, the tissues collected after anesthesia were analyzed by Western blot, qRT-PCR, biochemical, stereological, immunohistochemical, and histopathological techniques. Administration of PAC significantly increased the expression of tumor necrosis factor-alpha (TNF-α), Bax, cytochrome-c (cyt-c), and active caspase-3, as well as malondialdehyde (MDA) levels in liver tissue and decreased glutathione (GSH) levels compared with the control group. PAC also resulted in a significant increase in serum triglyceride (TG), cholesterol (CH), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels compared with the control group. Pathological changes such as microvesicular steatosis, the formation of Councilman bodies, an increase in total sinusoidal volume, and a decrease in the total number of hepatocytes were observed in the liver tissue of the PAC group. Almost all analysis results in the PAC + SL group were similar to those in the control group, and no significant pathological alterations were observed in this group. The data obtained show that SL protects the liver from the harmful effects of PAC, especially thanks to its TNF-α suppressor, anti-inflammatory, anti-apoptotic and antioxidant effects. Based on this result, in cases where PAC is used in cancer treatment, it can be recommended to be used together with SL to prevent harmful effects on healthy liver tissue and to continue treatment uninterruptedly and effectively.

Heterozygous Cc2d1a mice show sex-dependent changes in the Beclin-1/p62 ratio with impaired prefrontal cortex and hippocampal autophagy

Autism Spectrum Disorders (ASD) are a group of neurodevelopmental disorders characterized by repetitive behaviors, lack of social interaction and communication. CC2D1A is identified in patients as an autism risk gene. Recently, we suggested that heterozygous Cc2d1a mice exhibit impaired autophagy in the hippocampus. We now report the analysis of autophagy markers (Lc3, Beclin and p62) in different regions hippocampus, prefrontal cortex, hypothalamus and cerebellum, with an overall decrease in autophagy and changes in Beclin-1/p62 ratio in the hippocampus. We observed sex-dependent variations in transcripts and protein expression levels. Moreover, our analyses suggest that alterations in autophagy initiated in Cc2d1a heterozygous parents are variably transmitted to offspring, even when the offspring's genotype is wild type. Aberration in the autophagy mechanism may indirectly contribute to induce synapse alteration in the ASD brain.

Partial changes in apoptotic pathways in hippocampus and hypothalamus of Cc2d1a heterozygous

Alterations in the apoptosis pathway have been linked to changes in serotonin levels seen in autistic patients. Cc2d1a is a repressor of the HTR1A gene involved in the serotonin pathway. The hippocampus and hypothalamus of Cc2d1a ± mice were analyzed for the expression of apoptosis markers (caspase 3, 8 and 9). Gender differences were observed in the expression levels of the three caspases consistent with some altered activity in the open-field assay. The number of apoptotic cells was significantly increased. We concluded that apoptotic pathways are only partially affected in the pathogenesis of the Cc2d1a heterozygous mouse model. A) Apoptosis is suppressed because the cell does not receive a death signal, or the receptor cannot activate the caspase 8 pathway despite the death signal. B) Since Caspase 8 and Caspase 3 expression is downregulated in our mouse model, the mechanism of apoptosis is not activated.

Prkn knockout mice show autistic-like behaviors and aberrant synapse formation

Autism spectrum disorder (ASD) is a neurodevelopmental disorder with high genetic heterogeneity, affecting one in 44 children in the United States. Recent genomic sequencing studies from autistic human individuals indicate that PARK2, a gene that has long been considered in the pathogenesis of Parkinson's disease, is involved in ASD. Here, we report that Prkn knockout (KO) mice demonstrate autistic-like behaviors including impaired social interaction, elevated repetitive behaviors, and deficits in communication. In addition, Prkn KO mice show reduced neuronal activity in the context of sociability in the prelimbic cortex. Cell morphological examination of layer 5 prelimbic cortical neurons shows a reduction in dendritic arborization and spine number. Furthermore, biochemistry and immunocytochemistry analyses reveal alterations in synapse density and the molecular composition of synapses. These findings indicate that Prkn is implicated in brain development and suggest the potential use of the Prkn KO mouse as a model for autism research.

Amino Acids, B Vitamins, and Choline May Independently and Collaboratively Influence the Incidence and Core Symptoms of Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a developmental disorder of variable severity, characterized by difficulties in social interaction, communication, and restricted or repetitive patterns of thought and behavior. In 2018, the incidence of ASD was 2.4 times higher than estimated in 2000. Behavior and brain development abnormalities are present in the complex disorder of ASD. Nutritional status plays a key role in the incidence and severity of the core symptoms of ASD. The aim of this study was to review the available peer-reviewed studies that evaluated the relationship between amino acids, choline, B vitamins, and ASD incidence and/or severity of symptoms. Through examining plasma profiles, urine samples, and dietary intake, researchers found that low choline, abnormal amino acid, and low B vitamin levels were present in children with ASD compared to those without ASD. The evidence supports the need for future research that implements simultaneous supplementation of all essential nutrients in individuals with ASD and among prenatal mothers. Future evidence could lead to scientific breakthroughs, ultimately reducing the rates of ASD incidence and severity of symptoms by applying nutritional interventions in at-risk populations.

Autophagy deficiency in neurodevelopmental disorders

Autophagy is a cell self-digestion pathway through lysosome and plays a critical role in maintaining cellular homeostasis and cytoprotection. Characterization of autophagy related genes in cell and animal models reveals diverse physiological functions of autophagy in various cell types and tissues. In central nervous system, by recycling injured organelles and misfolded protein complexes or aggregates, autophagy is integrated into synaptic functions of neurons and subjected to distinct regulation in presynaptic and postsynaptic neuronal compartments. A plethora of studies have shown the neuroprotective function of autophagy in major neurodegenerative diseases, such as Alzheimer’s disease (AD), Parkinson’s disease (PD), Huntington’s disease (HD) and amyotrophic lateral sclerosis (ALS). Recent human genetic and genomic evidence has demonstrated an emerging, significant role of autophagy in human brain development and prevention of spectrum of neurodevelopmental disorders. Here we will review the evidence demonstrating the causal link of autophagy deficiency to congenital brain diseases, the mechanism whereby autophagy functions in neurodevelopment, and therapeutic potential of autophagy.

Thymoquinone improves testicular damage and sperm quality in experimentally varicocele-induced adolescent rats

The aim of this study was to investigate the protective and therapeutic effects of thymoquinone against the negative effects of varicocele on testicular tissue and sperm morphology. Five groups were formed by random selection from a total of 40 adult male Wistar rats (n = 8). Thymoquinone (5 mg/kg/day) was administered intraperitoneally to the varicocele-dimethyl sulfoxide-olive oil-thymoquinone (VT) group and the sham-thymoquinone group. At the end of the 60th day, all groups were anaesthetised and the left testis was removed from the body quickly. One half of the testis tissue, which was divided into two, was separated for biochemical and Western blot analysis, while the other half were fixed in Bouin's fixative. As a result of biochemical, molecular and histopathological analyses, a statistically significant increase was found in the varicocele group testicular tissues in the malondialdehyde level, apoptotic index, Bax expression, cytochrome c expression and Bax/Bcl-2 ratio compared with the sham group. In addition, histopathological changes characterised by partial or complete degeneration of the germinal epithelium were observed in the seminiferous tubules in the same group. Total oxidant status level and sperm count with abnormal morphology increased in varicocele group, whereas total antioxidant status level decreased. In the VT group, all of the biochemical, molecular and histopathological changes detected in the varicocele group were statistically significantly reduced. When the findings obtained in this study are evaluated, it can be said that thymoquinone has the potential to be used as a preventive and therapeutic pharmacological agent in the medical treatment of varicocele. Although the exact mechanism of action of thymoquinone has not been fully elucidated, the findings obtained in this study support the view that thymoquinone showed a cytoprotective effect by reducing apoptosis, oxidative stress and lipid peroxidation.

Novel alterations of CC2D1A as a candidate gene in a Turkish sample of patients with autism spectrum disorder

BACKGROUND

Autism spectrum disorder (ASD) is a neurodevelopmental disorder with large genetic background, but identification of pathogenic variants has proceeded slowly because hundreds of loci are involved in this complex disorder. CC2D1A gene firstly associated with the intellectual disability (ID) in a family with a large deletion. We aimed to contribute to the literature by sequencing this gene and by this way we report novel CC2D1A variations in patients with ASD.

METHODS

Forty families who have a child with a diagnosis of ASD were enrolled to the study. DNA samples were obtained from each family member. Bidirectional CC2D1A gene sequencing was performed with CEQ Cycle Sequencing Kit, and the products were analyzed on the Beckman CEQ 8000. All of the genetic analysis was conducted in Erciyes University Genome and Stem Cell Center (GENKOK).

RESULTS

According to the sequencing results, we defined new alterations in this gene with two SNPs in exon 15 and 19 (rs747172992 and rs1364074600) in our patients. We found a pathogenic variant in one patient. This variant was located in the acceptor region. Six of the variants were missense mutations. Additionally, six different benign variants were detected in 30 patients; however, they were not associated with ASD. Two patients carried multiple rare variants.

CONCLUSION

In vitro and in vivo functional analysis with this gene will help to understand its contribution to ASD pathogenesis. Future studies may help to elucidate the underlying biological mechanisms of these variants leading to the autism phenotype.

The influence of choline treatment on behavioral and neurochemical autistic-like phenotype in Mthfr-deficient mice

Imbalanced one carbon metabolism and aberrant autophagy is robustly reported in patients with autism. Polymorphism in the gene methylenetetrahydrofolate reductase (Mthfr), encoding for a key enzyme in this pathway is associated with an increased risk for autistic-spectrum-disorders (ASDs). Autistic-like core and associated behaviors have been described, with contribution of both maternal and offspring Mthfr^+/- genotype to the different domains of behavior. Preconception and prenatal supplementation with methyl donor rich diet to human subjects and mice reduced the risk for developing autism and autistic-like behavior, respectively. Here we tested the potential of choline supplementation to Mthfr-deficient mice at young-adulthood to reduce behavioral and neurochemical changes reminiscent of autism characteristics. We show that offspring of Mthfr^+/- mothers, whether wildtype or heterozygote, exhibit autistic-like behavior, altered brain p62 protein levels and LC3-II/LC3-I levels ratio, both, autophagy markers. Choline supplementation to adult offspring of Mthfr^+/- mothers for 14 days counteracted characteristics related to repetitive behavior and anxiety both in males and in females and improved social behavior solely in male mice. Choline treatment also normalized deviant cortical levels of the autophagy markers measured in male mice. The results demonstrate that choline supplementation even at adulthood, not tested previously, to offspring of Mthfr-deficient mothers, attenuates the autistic-like phenotype. If this proof of concept is replicated it might promote translation of these results to treatment recommendation for children with ASDs bearing similar genetic/metabolic make-up.