RESUMEN

Autism spectrum disorder (ASD) is known as a group of neurodevelopmental conditions including stereotyped and repetitive behaviors, besides social and sensorimotor deficits. Anatomical and functional evidence indicates atypical maturation of the striatum. Astrocytes regulate the maturation and plasticity of synaptic circuits, and impaired calcium signaling is associated with repetitive behaviors and atypical social interaction. Spontaneous calcium transients (SCT) recorded in the striatal astrocytes of the rat were investigated in the preclinical model of ASD by prenatal exposure to valproic acid (VPA). Our results showed sensorimotor delay, augmented glial fibrillary acidic protein -a typical intermediate filament protein expressed by astrocytes- and diminished expression of GABAA-ρ3 through development, and increased frequency of SCT with a reduced latency that resulted in a diminished amplitude in the VPA model. The convulsant picrotoxin, a GABAA (γ-aminobutyric acid type A) receptor antagonist, reduced the frequency of SCT in both experimental groups but rescued this parameter to control levels in the preclinical ASD model. The amplitude and latency of SCT were decreased by picrotoxin in both experimental groups. Nipecotic acid, a GABA uptake inhibitor, reduced the mean amplitude only for the control group. Nevertheless, nipecotic acid increased the frequency but diminished the latency in both experimental groups. Thus, we conclude that striatal astrocytes exhibit SCT modulated by GABAA-mediated signaling, and prenatal exposure to VPA disturbs this tuning.

Asunto(s)

Astrocitos , Cuerpo Estriado , Animales , Astrocitos/metabolismo , Astrocitos/efectos de los fármacos , Cuerpo Estriado/metabolismo , Cuerpo Estriado/efectos de los fármacos , Femenino , Embarazo , Ratas , Ácido Valproico/farmacología , Ratas Wistar , Picrotoxina/farmacología , Señalización del Calcio/efectos de los fármacos , Señalización del Calcio/fisiología , Modelos Animales de Enfermedad , Masculino , Calcio/metabolismo , Trastorno del Espectro Autista/metabolismo , Trastorno Autístico/metabolismo , Efectos Tardíos de la Exposición Prenatal/metabolismo

RESUMEN

Autism spectrum disorder (ASD) comprises a complex neurodevelopmental condition characterized by an impairment in social interaction, involving communication deficits and specific patterns of behaviors, like repetitive behaviors. ASD is clinically diagnosed and usually takes time, typically occurring not before four years of age. Genetic mutations affecting synaptic transmission, such as neuroligin and neurexin, are associated with ASD and contribute to behavioral and cognitive deficits. Recent research highlights the role of astrocytes, the brain's most abundant glial cells, in ASD pathology. Aberrant Ca2+ signaling in astrocytes is linked to behavioral deficits and neuroinflammation. Notably, the cytokine IL-6 overexpression by astrocytes impacts synaptogenesis. Altered neurotransmitter levels, disruptions in the blood-brain barrier, and cytokine dysregulation further contribute to ASD complexity. Understanding these astrocyte-related mechanisms holds promise for identifying ASD subtypes and developing targeted therapies.

Asunto(s)

Astrocitos , Trastorno del Espectro Autista , Neuronas , Trastorno del Espectro Autista/metabolismo , Trastorno del Espectro Autista/genética , Humanos , Astrocitos/metabolismo , Neuronas/metabolismo , Animales , Transmisión Sináptica , Barrera Hematoencefálica/metabolismo , Encéfalo/metabolismo

RESUMEN

Vitamin A (VA) has many functions in the body, some of which are key for the development and functioning of the nervous system, while some others might indirectly influence neural function. Both hypovitaminosis and hypervitaminosis A can lead to clinical manifestations of concern for individuals and for general global health. Scientific evidence on the link between VA and autism spectrum disorder (ASD) is growing, with some clinical studies and accumulating results obtained from basic research using cellular and animal models. Remarkably, it has been shown that VA deficiency can exacerbate autistic symptomatology. In turn, VA supplementation has been shown to be able to improve autistic symptomatology in selected groups of individuals with ASD. However, it is important to recognize that ASD is a highly heterogeneous condition. Therefore, it is important to clarify how and when VA supplementation can be of benefit for affected individuals. Here we delve into the relationship between VA and ASD, discussing clinical observations and mechanistic insights obtained from research on selected autistic syndromes and laboratory models to advance in defining how the VA signaling pathway can be exploited for treatment of ASD.

Asunto(s)

Trastorno del Espectro Autista , Vitamina A , Trastorno del Espectro Autista/metabolismo , Humanos , Vitamina A/metabolismo , Animales , Deficiencia de Vitamina A/complicaciones , Deficiencia de Vitamina A/metabolismo , Suplementos Dietéticos

RESUMEN

This study aimed to investigate the gut microbiota composition in children with autism spectrum disorder (ASD) compared to neurotypical (NT) children, with a focus on identifying potential differences in gut bacteria between these groups. The microbiota was analyzed through the massive sequencing of region V3-V4 of the 16S RNA gene, utilizing DNA extracted from stool samples of participants. Our findings revealed no significant differences in the dominant bacterial phyla (Firmicutes, Bacteroidota, Actinobacteria, Proteobacteria, Verrucomicrobiota) between the ASD and NT groups. However, at the genus level, notable disparities were observed in the abundance of Blautia, Prevotella, Clostridium XI, and Clostridium XVIII, all of which have been previously associated with ASD. Furthermore, a sex-based analysis unveiled additional discrepancies in gut microbiota composition. Specifically, three genera (Megamonas, Oscilibacter, Acidaminococcus) exhibited variations between male and female groups in both ASD and NT cohorts. Particularly noteworthy was the exclusive presence of Megamonas in females with ASD. Analysis of predicted metabolic pathways suggested an enrichment of pathways related to amine and polyamine degradation, as well as amino acid degradation in the ASD group. Conversely, pathways implicated in carbohydrate biosynthesis, degradation, and fermentation were found to be underrepresented. Despite the limitations of our study, including a relatively small sample size (30 ASD and 31 NT children) and the utilization of predicted metabolic pathways derived from 16S RNA gene analysis rather than metagenome sequencing, our findings contribute to the growing body of evidence suggesting a potential association between gut microbiota composition and ASD. Future research endeavors should focus on validating these findings with larger sample sizes and exploring the functional significance of these microbial differences in ASD. Additionally, there is a critical need for further investigations to elucidate sex differences in gut microbiota composition and their potential implications for ASD pathology and treatment.

Asunto(s)

Trastorno del Espectro Autista , Microbioma Gastrointestinal , Humanos , Microbioma Gastrointestinal/genética , Trastorno del Espectro Autista/microbiología , Trastorno del Espectro Autista/metabolismo , Femenino , Masculino , Niño , ARN Ribosómico 16S/genética , Bacterias/clasificación , Bacterias/genética , Bacterias/metabolismo , Bacterias/aislamiento & purificación , Heces/microbiología , Preescolar , Factores Sexuales , Caracteres Sexuales , Redes y Vías Metabólicas

RESUMEN

Background: The prevalence of autism spectrum disorder (ASD) has significantly risen in the past three decades, prompting researchers to explore the potential contributions of environmental factors during pregnancy to ASD development. One such factor of interest is gestational hypothyroxinemia (HTX), a frequent condition in pregnancy associated with cognitive impairments in the offspring. While retrospective human studies have linked gestational HTX to autistic traits, the cellular and molecular mechanisms underlying the development of ASD-like phenotypes remain poorly understood. This study used a mouse model of gestational HTX to evaluate ASD-like phenotypes in the offspring. Methods: To induce gestational HTX, pregnant mice were treated with 2-mercapto-1-methylimidazole (MMI), a thyroid hormones synthesis inhibitor, in the tap-drinking water from embryonic days (E) 10 to E14. A separate group received MMI along with a daily subcutaneous injection of T4, while the control group received regular tap water during the entire pregnancy. Female and male offspring underwent assessments for repetitive, anxious, and social behaviors from postnatal day (P) 55 to P64. On P65, mice were euthanized for the evaluation of ASD-related inflammatory markers in blood, spleen, and specific brain regions. Additionally, the expression of glutamatergic proteins (NLGN3 and HOMER1) was analyzed in the prefrontal cortex and hippocampus. Results: The HTX-offspring exhibited anxious-like behavior, a subordinate state, and impaired social interactions. Subsequently, both female and male HTX-offspring displayed elevated proinflammatory cytokines in blood, including IL-1ß, IL-6, IL-17A, and TNF-α, while only males showed reduced levels of IL-10. The spleen of HTX-offspring of both sexes showed increased Th17/Treg ratio and M1-like macrophages. In the prefrontal cortex and hippocampus of male HTX-offspring, elevated levels of IL-17A and reduced IL-10 were observed, accompanied by increased expression of hippocampal NLGN3 and HOMER1. All these observations were compared to those observed in the Control-offspring. Notably, the supplementation with T4 during the MMI treatment prevents the development of the observed phenotypes. Correlation analysis revealed an association between maternal T4 levels and specific ASD-like outcomes. Discussion: This study validates human observations, demonstrating for the first time that gestational HTX induces ASD-like phenotypes in the offspring, highlighting the need of monitoring thyroid function during pregnancy.

Asunto(s)

Trastorno del Espectro Autista , Efectos Tardíos de la Exposición Prenatal , Animales , Femenino , Embarazo , Trastorno del Espectro Autista/etiología , Trastorno del Espectro Autista/metabolismo , Ratones , Masculino , Efectos Tardíos de la Exposición Prenatal/metabolismo , Fenotipo , Conducta Animal , Hipotiroidismo/metabolismo , Tiroxina/sangre , Biomarcadores/metabolismo , Ratones Endogámicos C57BL , Complicaciones del Embarazo/metabolismo , Modelos Animales de Enfermedad , Inflamación/metabolismo , Conducta Social

RESUMEN

Zika virus (ZIKV) infection was first associated with Central Nervous System (CNS) infections in Brazil in 2015, correlated with an increased number of newborns with microcephaly, which ended up characterizing the Congenital Zika Syndrome (CZS). Here, we investigated the impact of ZIKV infection on the functionality of iPSC-derived astrocytes. Besides, we extrapolated our findings to a Brazilian cohort of 136 CZS children and validated our results using a mouse model. Interestingly, ZIKV infection in neuroprogenitor cells compromises cell migration and causes apoptosis but does not interfere in astrocyte generation. Moreover, infected astrocytes lost their ability to uptake glutamate while expressing more glutamate transporters and secreted higher levels of IL-6. Besides, infected astrocytes secreted factors that impaired neuronal synaptogenesis. Since these biological endophenotypes were already related to Autism Spectrum Disorder (ASD), we extrapolated these results to a cohort of children, now 6-7 years old, and found seven children with ASD diagnosis (5.14 %). Additionally, mice infected by ZIKV revealed autistic-like behaviors, with a significant increase of IL-6 mRNA levels in the brain. Considering these evidence, we inferred that ZIKV infection during pregnancy might lead to synaptogenesis impairment and neuroinflammation, which could increase the risk for ASD.

Asunto(s)

Astrocitos , Trastorno del Espectro Autista , Enfermedades Neuroinflamatorias , Sinapsis , Infección por el Virus Zika , Virus Zika , Infección por el Virus Zika/patología , Infección por el Virus Zika/metabolismo , Infección por el Virus Zika/virología , Infección por el Virus Zika/complicaciones , Trastorno del Espectro Autista/virología , Trastorno del Espectro Autista/metabolismo , Trastorno del Espectro Autista/etiología , Trastorno del Espectro Autista/patología , Humanos , Animales , Ratones , Virus Zika/fisiología , Femenino , Niño , Sinapsis/metabolismo , Sinapsis/patología , Enfermedades Neuroinflamatorias/virología , Enfermedades Neuroinflamatorias/metabolismo , Enfermedades Neuroinflamatorias/patología , Enfermedades Neuroinflamatorias/etiología , Astrocitos/virología , Astrocitos/metabolismo , Astrocitos/patología , Masculino , Interleucina-6/metabolismo , Interleucina-6/genética , Embarazo , Factores de Riesgo , Células Madre Pluripotentes Inducidas/virología , Células Madre Pluripotentes Inducidas/metabolismo , Brasil/epidemiología , Modelos Animales de Enfermedad , Neurogénesis

RESUMEN

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder that involves functional and structural defects in selective central nervous system (CNS) regions, harming the individual capability to process and respond to external stimuli, including impaired verbal and non-verbal communications. Etiological causes of ASD have not been fully clarified; however, prenatal activation of the innate immune system by external stimuli might infiltrate peripheral immune cells into the fetal CNS and activate cytokine secretion by microglia and astrocytes. For instance, genomic and postmortem histological analysis has identified proinflammatory gene signatures, microglia-related expressed genes, and neuroinflammatory markers in the brain during ASD diagnosis. Active neuroinflammation might also occur during the developmental stage, promoting the establishment of a defective brain connectome and increasing susceptibility to ASD after birth. While still under investigation, we tested the hypothesis whether the monocyte chemoattractant protein-1 (MCP-1) signaling is prenatally programmed to favor peripheral immune cell infiltration and activate microglia into the fetal CNS, setting susceptibility to autism-like behavior. In this review, we will comprehensively provide the current understanding of the prenatal activation of MCP-1 signaling by external stimuli during the developmental stage as a new selective node to promote neuroinflammation, brain structural alterations, and behavioral defects associated to ASD diagnosis.

Asunto(s)

Quimiocina CCL2 , Transducción de Señal , Humanos , Quimiocina CCL2/metabolismo , Animales , Susceptibilidad a Enfermedades , Trastorno Autístico/metabolismo , Trastorno Autístico/patología , Femenino , Microglía/metabolismo , Microglía/patología , Embarazo , Trastorno del Espectro Autista/metabolismo , Trastorno del Espectro Autista/patología , Encéfalo/metabolismo , Encéfalo/patología , Desarrollo Fetal/fisiología

RESUMEN

Autism spectrum disorder (ASD) is a diverse group of neurodevelopmental conditions with complex origins. Individuals with ASD present various neurobiological abnormalities, including an altered immune response in the central nervous system and other tissues. Animal models like the C58/J inbred mouse strain are used to study biological characteristics of ASD. This strain is considered an idiopathic autism model because of its demonstrated reduced social preference and repetitive behaviours. Notably, C58/J mice exhibit alterations in dendritic arbour complexity, density and dendritic spines maturation in the hippocampus and prefrontal cortex (PFC), but inflammatory-related changes have not been explored in these mice. In this study, we investigated proinflammatory markers in the hippocampus and PFC of adult male C58/J mice. We discovered elevated levels of interferon gamma (IFN-γ) and monocyte chemoattractant protein 1 (MCP-1) in the hippocampus, suggesting increased inflammation, alongside a reduction in the anti-inflammatory enzyme arginase 1 (ARG1). Conversely, the PFC displayed reduced levels of TNF-α and MCP-1. Microglial analysis revealed higher levels of transmembrane protein 119 (TMEM119) and increased microglial density in a region-specific manner of the autistic-like mice, particularly in the PFC and hippocampus. Additionally, an augmented expression of the fractalkine receptor CX3CR1 was observed in the hippocampus and PFC of C58/J mice. Microglial morphological analysis shows no evident changes in the hippocampus of mice with autistic-like behaviours versus wild-type strain. These region-specific changes can contribute to modulate processes like inflammation or synaptic pruning in the C58/J mouse model of idiopathic autism.

Asunto(s)

Trastorno del Espectro Autista , Trastorno Autístico , Ratones , Masculino , Animales , Trastorno Autístico/metabolismo , Trastorno del Espectro Autista/metabolismo , Microglía/metabolismo , Ratones Endogámicos , Corteza Prefrontal/metabolismo , Hipocampo/metabolismo , Inflamación/metabolismo , Modelos Animales de Enfermedad , Ratones Endogámicos C57BL

RESUMEN

Autism Spectrum Disorder (ASD) is a set of neurodevelopmental disorders mainly characterized by repetitive, restrictive and stereotypical behaviors, and impaired communication skills. Several lines of evidence indicate that alterations of the immune system account for ASD development, including the presence of brain-reactive antibodies, abnormal T cell activation, altered cytokine levels in brain, cerebrospinal fluid and peripheral blood circulation, increased levels of circulating monocytes, and dysregulation in Natural Killer (NK) cells activity. Regarding NK cells, a lower cytotoxic activity, a higher level of activation and an increased number of these cells in individuals with ASD have been described. In 2019, a study showed that NK cells derived from patients with ASD show a characteristic pattern of NKG2C overexpression, highlighting the importance of the NK cell pathway in ASD. In fact, the study of genes related to NK cell activity has proven to be an excellent research target, both in terms of susceptibility as well as a marker for the different clinical manifestations observed in ASD individuals. Here, we evaluated the influence of KLRC2 gene deletion as well as KLRK1 rs1049174 and rs2255336 variants in a cohort of 185 children diagnosed with ASD and their respective biological parents in southern Brazil. Of note, this is the first study concerning genetic variants of the KLRC2 and KLRK1 genes in an ASD sample. The KLRC2 gene deletion (p = 0.001; pc = 0.009), KLRK1 rs1049174 (p = 0.005; pc = 0.045) and KLRK1 rs2255336 (p = 0.001; pc = 0.009) were associated with epilepsy in ASD patients. The results indicate that KLRC2 deletion, KLRK1 rs2255336, and KLRK1 rs1049174 could be involved in epilepsy manifestation in ASD patients, possibly impacting the NK dysregulation already described in ASD and epileptic patients.

Asunto(s)

Trastorno del Espectro Autista , Epilepsia , Niño , Humanos , Trastorno del Espectro Autista/genética , Trastorno del Espectro Autista/metabolismo , Células Asesinas Naturales , Encéfalo/metabolismo , Epilepsia/genética , Brasil , Subfamília C de Receptores Similares a Lectina de Células NK/metabolismo

RESUMEN

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder characterized by a persistent impairment of social skills, including aspects of perception, interpretation, and response, combined with restricted and repetitive behavior. ASD is a complex and multifactorial condition, and its etiology could be attributed to genetic and environmental factors. Despite numerous clinical and experimental studies, no etiological factor, biomarker, and specific model of transmission have been consistently associated with ASD. However, an imbalance in cholesterol levels has been observed in many patients, more specifically, a condition of hypocholesterolemia, which seems to be shared between ASD and ASD-related genetic syndromes such as fragile X syndrome (FXS), Rett syndrome (RS), and Smith- Lemli-Opitz (SLO). Furthermore, it is known that alterations in cholesterol levels lead to neuroinflammation, oxidative stress, impaired myelination and synaptogenesis. Thus, the aim of this review is to discuss the cholesterol metabolic pathways in the ASD context, as well as in genetic syndromes related to ASD, through clinical observations and animal models. In fact, SLO, FXS, and RS patients display early behavioral markers of ASD followed by cholesterol disturbances. Several studies have demonstrated the role of cholesterol in psychiatric conditions and how its levels modulate brain neurodevelopment. This review suggests an important relationship between ASD pathology and cholesterol metabolism impairment; thus, some strategies could be raised - at clinical and pre-clinical levels - to explore whether cholesterol metabolism disturbance has a generally adverse effect in exacerbating the symptoms of ASD patients.

Asunto(s)

Trastorno del Espectro Autista , Animales , Trastorno del Espectro Autista/complicaciones , Trastorno del Espectro Autista/metabolismo , Colesterol/sangre , Colesterol/metabolismo , Síndrome del Cromosoma X Frágil , Modelos Animales , Trastornos del Neurodesarrollo , Síndrome de Rett , Hipercolesterolemia

RESUMEN

Brain-derived neurotrophic factor (BDNF) and insulin-like growth factor 1 (IGF-1) promote the development and maintenance of neural circuits. Alterations in these factors might contribute to autism spectrum disorder (ASD). We asked whether serum BDNF, proBDNF, and IGF-1 levels are altered in an ASD population compared to controls. We measured serum BDNF, proBDNF, and IGF-1 immunoreactive protein in boys and girls aged 5-15 years old with mild to moderate ASD and non-autistic controls by ELISA. IGF-1 was increased in ASD serum compared to controls and was correlated with age and with CARS scores. Serum BDNF levels did not differ between groups, however, proBDNF serum levels were decreased in subjects with ASD compared to non-autistic controls. Medicated, but not unmedicated, ASD subjects exhibited lower serum proBDNF levels compared to controls, while neither IGF-1 nor BDNF levels differed between treatment groups. These data support the involvement of proBDNF and IGF-1 in the pathogenesis and treatment of autism.

Asunto(s)

Trastorno del Espectro Autista , Trastorno Autístico , Factor Neurotrófico Derivado del Encéfalo/sangre , Factor I del Crecimiento Similar a la Insulina/análisis , Adolescente , Trastorno del Espectro Autista/metabolismo , Niño , Preescolar , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Masculino

RESUMEN

Oligogenic inheritance of autism spectrum disorder (ASD) has been supported by several studies. However, little is known about how the risk variants interact and converge on causative neurobiological pathways. We identified in an ASD proband deleterious compound heterozygous missense variants in the Reelin (RELN) gene, and a de novo splicing variant in the Cav3.2 calcium channel (CACNA1H) gene. Here, by using iPSC-derived neural progenitor cells (NPCs) and a heterologous expression system, we show that the variant in Cav3.2 leads to increased calcium influx into cells, which overactivates mTORC1 pathway and, consequently, further exacerbates the impairment of Reelin signaling. Also, we show that Cav3.2/mTORC1 overactivation induces proliferation of NPCs and that both mutant Cav3.2 and Reelin cause abnormal migration of these cells. Finally, analysis of the sequencing data from two ASD cohorts-a Brazilian cohort of 861 samples, 291 with ASD; the MSSNG cohort of 11,181 samples, 5,102 with ASD-revealed that the co-occurrence of risk variants in both alleles of Reelin pathway genes and in one allele of calcium channel genes confer significant liability for ASD. Our results support the notion that genes with co-occurring deleterious variants tend to have interconnected pathways underlying oligogenic forms of ASD.

Asunto(s)

Trastorno del Espectro Autista , Canales de Calcio Tipo T , Trastorno del Espectro Autista/genética , Trastorno del Espectro Autista/metabolismo , Canales de Calcio/genética , Canales de Calcio Tipo T/genética , Predisposición Genética a la Enfermedad , Humanos , Diana Mecanicista del Complejo 1 de la Rapamicina/genética , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Herencia Multifactorial

RESUMEN

Autism spectrum disorder (ASD) is a prevalent neurodevelopmental disorder characterized by several alterations, including disorganized brain cytoarchitecture and excitatory/inhibitory (E/I) imbalance. We aimed to analyze aspects associated with the inhibitory components in ASD, using bioinformatics to develop notions about embryonic life and tissue analysis for postnatal life. We analyzed microarray and RNAseq datasets of embryos from different ASD models, demonstrating that regions involved in neuronal development are affected. We evaluated the effect of prenatal treatment with resveratrol (RSV) on the neuronal organization and quantity of parvalbumin-positive (PV+), somatostatin-positive (SOM+), and calbindin-positive (CB+) GABAergic interneurons, besides the levels of synaptic proteins and GABA receptors in the medial prefrontal cortex (mPFC) and hippocampus (HC) of the ASD model induced by valproic acid (VPA). VPA increased the total number of neurons in the mPFC, while it reduced the number of SOM+ neurons, as well as the proportion of SOM+, PV+, and CB+ neurons (subregion-specific manner), with preventive effects of RSV. In summary, metabolic alterations or gene expression impairments could be induced by VPA, leading to extensive damage in the late developmental stages. By contrast, due to its antioxidant, neuroprotective, and opposite action on histone properties, RSV may avoid damages induced by VPA.

Asunto(s)

Trastorno del Espectro Autista , Trastorno Autístico , Efectos Tardíos de la Exposición Prenatal , Resveratrol , Ácido Valproico , Animales , Trastorno del Espectro Autista/metabolismo , Trastorno Autístico/inducido químicamente , Trastorno Autístico/tratamiento farmacológico , Trastorno Autístico/genética , Modelos Animales de Enfermedad , Femenino , Interneuronas/metabolismo , Embarazo , Efectos Tardíos de la Exposición Prenatal/inducido químicamente , Ratas , Resveratrol/uso terapéutico , Ácido Valproico/efectos adversos

RESUMEN

Autism spectrum disorder (ASD) is a heterogeneous neurodevelopment disorder resulting from different etiological factors, both genetic and/or environmental. These factors can lead to abnormal neuronal development on dendrite and synaptic function at the central nervous system. Recent studies have shown that a subset of ASD patients display increased circulation levels of the tyrosine metabolite, p-cresol, related to chronic intestinal disorders because of dysbiosis of the intestinal microbiota. In particular, abnormal presence of intestinal Clostridium sp. has been linked to high levels of p-cresol in ASD children younger than 8 years. However, the role of p-cresol during development of the central nervous system is unknown. Here, we evaluated in vitro the effect of p-cresol on neurite outgrowth in N2a and PC12 cell lines and dendritic morphology, synaptic density, neuronal activity, and calcium responses in primary rat hippocampal neurons. p-cresol inhibits neural differentiation and neurites outgrowth in N2a and PC12 neuronal cell lines. In hippocampal neuronal cultures, Sholl's analysis shows a decrease in the dendritic arborization of neurons treated with p-cresol. Synaptic density analyzed with the synaptic markers Piccolo and Shank2 is diminished in hippocampal neurons treated with p-cresol. Electrically evoked intracellular calcium rise was drastically, but reversely, blocked by p-cresol, whereas that spontaneous neuronal activity was severely affected by early addition of the metabolite. These findings show that p-cresol alters dendrite development, synaptogenesis, and synapse function of neurons in culture, therefore, neuronal alterations occurring in ASD children may be related to this metabolite and dysbiosis of the intestinal microbiota.

Asunto(s)

Trastorno del Espectro Autista , Animales , Trastorno del Espectro Autista/metabolismo , Calcio/metabolismo , Células Cultivadas , Cresoles , Disbiosis/metabolismo , Hipocampo/metabolismo , Humanos , Neuronas/metabolismo , Ratas , Sinapsis/metabolismo

RESUMEN

The lack of specific pharmacological therapy for Autistic Spectrum Disorder (ASD) and its clinical heterogeneity demand efforts directed toward the identification of biomarkers to aid in diagnosis. Proteomics offers a new perspective for studying the altered proteins associated with autism spectrum disorders (ASD) and we have saliva as an easy-to-collect biological fluid with important biomolecules for investigating biomarkers in various diseases. In this sense, saliva could be used to identify potential biomarkers of ASD. In the current work, saliva samples were collected from children with different degrees of ASD and healthy children and proteomics approaches were applied to generate data on differentially expressed proteins between groups which will serve as a basis for future validation studies as protein markers. Data are available via ProteomeXchange with identifier PXD030065. As results, 132 proteins were present in 80% of the saliva pools of all analyzed groups. Twenty-five proteins were identified as overexpressed in the group of severe and mild/moderate ASD carriers, among which, eight were identified as potential biomarkers for ASD.

Asunto(s)

Trastorno del Espectro Autista , Proteómica , Trastorno del Espectro Autista/diagnóstico , Trastorno del Espectro Autista/metabolismo , Biomarcadores/metabolismo , Niño , Humanos , Saliva/metabolismo

RESUMEN

Autism spectrum disorder (ASD) is a disease characterized by reduced social interaction and stereotypic behaviors and related to macroscopic volumetric changes in cerebellar and somatosensory cortices (SPP). Epidemiological and preclinical models have confirmed that a proinflammatory profile during fetal development increases ASD susceptibility after birth. Here, we aimed to globally identify the effect of maternal exposure to high-energy dense diets, which we refer to as cafeteria diet (CAF) on peripheral and central proinflammatory profiles, microglia reactivity, and volumetric brain changes related to assisting defective social interaction in the mice offspring. We found a sex-dependent effect of maternal exposure to CAF diet or inoculation of the dsARN mimetic Poly (I:C) on peripheral proinflammatory and social interaction in the offspring. Notably, maternal exposure to CAF diet impairs social interaction and favors an increase in anxiety in male but not female offspring. Also, CAF diet exposure or Poly (I:C) inoculation during fetal programming promote peripheral proinflammatory profile in the ASD-diagnosed male but not in females. Selectively, we found a robust accumulation of the monocyte chemoattractant protein-1 (MCP-1) in plasma of ASD-diagnosed males exposed to CAF during fetal development. Biological assessment of MCP-1 signaling in brain confirms that systemic injection of MCP-1-neutralizing antibody reestablished social interaction and blocked anxiety, accompanied by a reduction in cerebellar lobule X (CbX) volume and an increase volume of the primary somatosensory (SSP) cortex in male offspring. These data highlight the contribution of diet-dependent MCP-1 signaling on volumetric brain changes and microglia morphology promoting ASD-like behavior in male mice.

Asunto(s)

Trastorno del Espectro Autista , Quimiocina CCL2 , Efectos Tardíos de la Exposición Prenatal , Animales , Trastorno del Espectro Autista/metabolismo , Trastorno del Espectro Autista/patología , Encéfalo/anatomía & histología , Encéfalo/metabolismo , Quimiocina CCL2/metabolismo , Femenino , Masculino , Ratones , Microglía/citología , Embarazo , Conducta Social

RESUMEN

In recent years, accumulating evidence has shown that the innate immune complement system is involved in several aspects of normal brain development and in neurodevelopmental disorders, including autism spectrum disorder (ASD). Although abnormal expression of complement components was observed in post-mortem brain samples from individuals with ASD, little is known about the expression patterns of complement molecules in distinct cell types in the developing autistic brain. In the present study, we characterized the mRNA and protein expression profiles of a wide range of complement system components, receptors and regulators in induced pluripotent stem cell (iPSC)-derived neural progenitor cells, neurons and astrocytes of individuals with ASD and neurotypical controls, which constitute in vitro cellular models that recapitulate certain features of both human brain development and ASD pathophysiology. We observed that all the analyzed cell lines constitutively express several key complement molecules. Interestingly, using different quantification strategies, we found that complement C4 mRNA and protein are expressed in significantly lower levels by astrocytes derived from ASD individuals compared to control astrocytes. As astrocytes participate in synapse elimination, and diminished C4 levels have been linked to defective synaptic pruning, our findings may contribute to an increased understanding of the atypically enhanced brain connectivity in ASD.

Asunto(s)

Astrocitos/patología , Trastorno del Espectro Autista/patología , Complemento C4/metabolismo , Células Madre Pluripotentes Inducidas/patología , Células-Madre Neurales/patología , Neuronas/patología , Astrocitos/metabolismo , Trastorno del Espectro Autista/genética , Trastorno del Espectro Autista/metabolismo , Células Cultivadas , Complemento C4/genética , Humanos , Células Madre Pluripotentes Inducidas/metabolismo , Células-Madre Neurales/metabolismo , Plasticidad Neuronal/fisiología , Neuronas/metabolismo

RESUMEN

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) regulates several cellular processes including survival, proliferation, and metabolism. In the brain, PTEN is a key modulator of synaptic function, and is involved in regulating synaptogenesis, connectivity, and synaptic plasticity. Herein we discuss how alterations in PTEN can disturb these mechanisms, thus compromising normal synaptic function and consequently contributing to behavioral and cognitive phenotypes observed in autism spectrum disorder (ASD). As the role of PTEN in synaptic function is linked to ASD, a deeper understanding of this interaction will shed light on the pathological mechanisms involved in ASD, contributing to the development of new therapies.

Asunto(s)

Trastorno del Espectro Autista/metabolismo , Trastorno del Espectro Autista/fisiopatología , Plasticidad Neuronal/fisiología , Fosfohidrolasa PTEN/metabolismo , Femenino , Humanos , Masculino , Transducción de Señal/fisiología

RESUMEN

Atypical connectivity between brain regions and altered structure of the corpus callosum (CC) in imaging studies supports the long-distance hypoconnectivity hypothesis proposed for autism spectrum disorder (ASD). The aim of this study was to unveil the CC ultrastructural and cellular changes employing the valproic acid (VPA) rat model of ASD. Male Wistar rats were exposed to VPA (450 mg/kg i.p.) or saline (control) during gestation (embryonic day 10.5), and maturation, exploration, and social behavior were subsequently tested. Myelin content, ultrastructure, and oligodendroglial lineage were studied in the CC at post-natal days 15 (infant) and 36 (juvenile). As a functional outcome, brain metabolic activity was determined by positron emission tomography. Concomitantly with behavioral deficits in juvenile VPA rats, the CC showed reduced myelin basic protein, conserved total number of axons, reduced percentage of myelinated axons, and aberrant and less compact arrangements of myelin sheath ultrastructure. Mature oligodendrocytes decreased and oligodendrocyte precursors increased in the absence of astrogliosis or microgliosis. In medial prefrontal and somatosensory cortices of juvenile VPA rats, myelin ultrastructure and oligodendroglial lineage were preserved. VPA animals exhibited global brain hypometabolism and local hypermetabolism in brain regions relevant for ASD. In turn, the CC of infant VPA rats showed reduced myelin content but preserved oligodendroglial lineage. Our findings indicate that CC hypomyelination is established during infancy and prior to oligodendroglial pattern alterations, which suggests that axon-oligodendroglia communication could be compromised in VPA animals. Thus, CC hypomyelination may underlie white matter alterations and contribute to atypical patterns of connectivity and metabolism found in ASD.

Asunto(s)

Trastorno del Espectro Autista/metabolismo , Cuerpo Calloso/metabolismo , Red Nerviosa/metabolismo , Efectos Tardíos de la Exposición Prenatal/metabolismo , Conducta Social , Ácido Valproico/toxicidad , Animales , Trastorno del Espectro Autista/inducido químicamente , Trastorno del Espectro Autista/patología , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Encéfalo/patología , Cuerpo Calloso/efectos de los fármacos , Cuerpo Calloso/patología , Conducta Exploratoria/efectos de los fármacos , Conducta Exploratoria/fisiología , Femenino , Masculino , Red Nerviosa/efectos de los fármacos , Red Nerviosa/patología , Embarazo , Efectos Tardíos de la Exposición Prenatal/inducido químicamente , Efectos Tardíos de la Exposición Prenatal/patología , Ratas , Ratas Wistar , Tomografía Computarizada de Emisión de Fotón Único/métodos

RESUMEN

BACKGROUND: Autism spectrum disorders (ASD) are synaptopathies characterized by area-specific synaptic alterations and neuroinflammation. Structural and adhesive features of hippocampal synapses have been described in the valproic acid (VPA) model. However, neuronal and microglial contribution to hippocampal synaptic pattern and its time-course of appearance is still unknown. METHODS: Male pups born from pregnant rats injected at embryonic day 10.5 with VPA (450 mg/kg, i.p.) or saline (control) were used. Maturation, exploratory activity and social interaction were assessed as autistic-like traits. Synaptic, cell adhesion and microglial markers were evaluated in the CA3 hippocampal region at postnatal day (PND) 3 and 35. Primary cultures of hippocampal neurons from control and VPA animals were used to study synaptic features and glutamate-induced structural remodeling. Basal and stimuli-mediated reactivity was assessed on microglia primary cultures isolated from control and VPA animals. RESULTS: At PND3, before VPA behavioral deficits were evident, synaptophysin immunoreactivity and the balance between the neuronal cell adhesion molecule (NCAM) and its polysialylated form (PSA-NCAM) were preserved in the hippocampus of VPA animals along with the absence of microgliosis. At PND35, concomitantly with the establishment of behavioral deficits, the hippocampus of VPA rats showed fewer excitatory synapses and increased NCAM/PSA-NCAM balance without microgliosis. Hippocampal neurons from VPA animals in culture exhibited a preserved synaptic puncta number at the beginning of the synaptogenic period in vitro but showed fewer excitatory synapses as well as increased NCAM/PSA-NCAM balance and resistance to glutamate-induced structural synaptic remodeling after active synaptogenesis. Microglial cells isolated from VPA animals and cultured in the absence of neurons showed similar basal and stimuli-induced reactivity to the control group. Results indicate that in the absence of glia, hippocampal neurons from VPA animals mirrored the in vivo synaptic pattern and suggest that while neurons are primed during the prenatal period, hippocampal microglia are not intrinsically altered. CONCLUSIONS: Our study suggests microglial role is not determinant for developing neuronal alterations or counteracting neuronal outcome in the hippocampus and highlights the crucial role of hippocampal neurons and structural plasticity in the establishment of the synaptic alterations in the VPA rat model.

Asunto(s)

Anticonvulsivantes , Trastorno del Espectro Autista/inducido químicamente , Hipocampo/efectos de los fármacos , Neuronas/efectos de los fármacos , Sinapsis/efectos de los fármacos , Ácido Valproico , Animales , Trastorno del Espectro Autista/metabolismo , Conducta Animal/efectos de los fármacos , Células Cultivadas , Modelos Animales de Enfermedad , Femenino , Hipocampo/metabolismo , Hipocampo/ultraestructura , Masculino , Microglía/efectos de los fármacos , Moléculas de Adhesión de Célula Nerviosa/metabolismo , Plasticidad Neuronal/efectos de los fármacos , Neuronas/metabolismo , Neuronas/ultraestructura , Fosfoproteínas Fosfatasas/metabolismo , Embarazo , Ratas Wistar