2020

Role of Gut Mucosal Immunity on Behavioral and Neuroinflammatory Profile in a Mouse Model of Autism – The Early-Life Immune-Activation Model

Monica Boirivant, Laura Ricceri, Roberta De Simone, Rosa Luisa Potenza
Istituto Superiore di Sanità in Rome, Italy

Inflammatory and immune changes are recognized as pivotal mechanisms in ASD, particularly the ones involving the microbiota-mucosal immune response development. Few data are so far available in ASD mouse models concerning the primary contribution of mucosal immune dysfunction to behavioral and neuroinflammatory profiles as well as to dysbiosis. This project aims to investigate the role of gut mucosal immunity on behavioral and neuroinflammatory profile in the early-life immune activation mouse (EIA), a model including both prenatal and postnatal immune challenges. We plan to achieve our aim by the evaluation of the effect of selective blockade of gut-experienced lymphocyte traffic to intestinal lamina propria (by the administration of an antibody directed against the integrin alpha4 beta7, an integrin responsible for lymphocyte trafficking in the gut mucosa). The effects of the treatment will be assessed on ASD-behavioral phenotype, on local (brain and gut-associated lymphoid tissue) and systemic (blood and spleen) immune-inflammatory changes, as well as on fecal microbiota composition. Results will:  a) clarify the mucosal contribution in ASD pathogenesis and b) possibly provide specific biomarkers to be used in future studies to identify subsets of ASD patients for personalized therapeutic approaches.

The Relationship between Hypermobility-Related Disorders in Mothers with Fragile X premutation, Maternal Fragile X Mental Retardation Protein (FMRP) Levels, and Autism Risk in the Child

Carrie Buchanan, MD, Greenwood Genetic Center
Emily Casanova, PhD

Previous research suggests that hypermobility-related disorders in mothers, such as Ehlers-Danlos syndrome (EDS), may be a significant risk factor for development of autism in their children. Our team has identified an EDS-like presentation in a subset of adult women with the Fragile X premutation. Meanwhile, roughly 50% of children with Fragile X syndrome (FXS) develop autism. However, it has usually been assumed that the variables underlying that risk are due to differences in genetic background. In this study, we will be investigating the maternal EDS presentation in Fragile X premutation and its potential relationship to the occurrence of autism in the child as a first step towards addressing the roles of the uterine environment in autism risk. In addition, because our preliminary data suggests the EDS-like presentation in Fragile X premutation may be associated with unusually low fragile X mental retardation protein (FMRP) levels, we will be collecting blood samples to measure FMRP levels in order to further study its relationship with hypermobility in these mothers.

Quantitative Subcellular Proteomics in Children and Adults with Idiopathic Autism

S. Hossein Fatemi, MD, PhD
University of Minnesota

Autism is a severe neurodevelopmental disorder with a rising prevalence of 18.5 per 1000 (1 in 54) in the United States. There have been few studies of the proteome of brains of individuals with autism. Our long-range goal is to identify biomarkers for autism by combining subcellular fractionation and proteomics. The objective of the current application is to determine the subcellular proteomes of individuals with autism vs. controls. The central hypothesis is that proteomics will identify unique subcellular proteomes in subjects with autism vs. controls and that there will be differences related to age and brain region. The rationale for the current proposal is that there is a dearth of brain subcellular proteomic studies related to autism. The project consists of the following specific aim: Determine the proteome of the synaptic fraction in superior frontal cortex (BA9) and cerebellar vermis of subjects with idiopathic autism vs. healthy controls. Our work is innovative because these studies will provide important information about protein dysregulation in autism.

Integrity of Vision and Eye Morphology in Autism Spectrum Disorders

Vanessa Troiani, PhD and Antoinette Dicriscio, PhD

Numerous studies have identified atypical visual attention and perception within Autism Spectrum Disorders (ASD), yet there is relatively little research on eye morphology, clinical measures of vision, and/or ocular function in these individuals. A few small studies have noted increased prevalence of refractive errors and optic nerve abnormalities in those with ASD, suggesting that atypical visual processing and perception may be driven, in part, by abnormal morphology and function in the eye and retina. In order to dramatically improve our understanding of atypical vision in ASD, we will leverage existing clinical optometry and ophthalmologic records to characterize abnormal eye and retinal features associated with ASD. Critically, the use of existing data from electronic health records will enable characterization of ocular function in a large sample that includes both low and high functioning individuals. Additionally, we will recruit a subsample of individuals seeking an ASD diagnosis at our neurodevelopmental clinic in order to assess the relationship between functional visual metrics, ocular anomalies, and their association with core diagnostic traits of ASD. Understanding differences in eye-level metrics in individuals with ASD will lay the groundwork for understanding the link between eye function and social, cognitive, and perceptual skills.

Autoantibody Mediated Pathology in Clinical Maternal Autoantibody Mediated (MAR) Autism Spectrum Disorder

Judy Van de Water, PhD
UC Davis, MIND Institute

The goal of this study is to understand the mechanisms driving the autoantibody mediated pathology in clinical Maternal Autoantibody Mediated (MAR) ASD, the most prevalent ASD subtype identified to date. Identification of disrupted cell-specific signaling pathways or the molecules involved provides an opportunity for early diagnostic or therapeutic intervention strategies.

One aim of this proposal is to verify the distribution and uptake of maternal MAR IgG throughout the brain. Preliminary analysis of MAR offspring suggests targeting of IgG to specific cells in the brain. Based upon the location and shape of the labeled cells, we hypothesize that MAR autoantibodies (aAbs) preferentially target neural precursor cells (NPCs). To validate the extent of Ab deposition in the brain, and to identify antibody-targeted cells, we will conduct multiplexed immunohistochemistry (IHC) on MAR rat brain tissue, using cell-specific markers for NPCs and differentiated cells, to detect IgG colocalization in the early postnatal rat brain. We also will determine how aAbs may interact with NPCs using cultured embryonic day 18 (E18) rat cortical tissue to examine NPC uptake of purified IgG from MAR rat dams. NPCs isolated from unexposed pups will be cultured with labeled MAR rat IgG, coupled with Fc-blocking strategies to examine whether Fc-receptor uptake may facilitate aAb uptake into cells.

We will also evaluate the effects of MAR aAb exposure on brain inflammation. Our hypothesis is that MAR IgG exposure during gestation will result in altered brain cytokine levels. To identify the nature of this response, we will examine brain lysates from post-natal day 2 (P2) MAR-exposed offspring to measure cytokines and chemokines related to inflammation, cell growth, and immune regulation. Interestingly, evaluation of preliminary cytokine data at P2 suggests upregulation of IL-6 and IFN-????, cytokines secreted mainly by glial subtypes in the brain. However, co-localization of IgG within glial cells was not apparent in preliminary IHC analysis. Therefore, we propose that the altered cytokine profile in P2 cortical brain lysates is a result of NPC-glia crosstalk. To evaluate this hypothesis, we will expose primary astrocytes and microglia to NPC culture supernatants from cells exposed to MAR or control rat IgG. This will allow assessment of the effects of MAR IgG on NPC-glia signaling during early development. We will determine if NPC-induced stimulation of astrocytes or microglia contributes to the altered cytokine secretion profile observed in neonatal animals exposed to MAR IgG treatment.

Probiotics, Microbiota, and Immunity: Therapy and Biomarkers of Social Behavior in Children Diagnosed with Autism Spectrum Disorders

Elisabetta Volpe, PhD
Santa Lucia Foundation – Molecular Neuroimmunology Unit

This study aims to test the potential benefit of Lactobacillus Reuteri MM4-1A in social behavior of children diagnosed with ASD. The project arises from recent studies in murine models demonstrating the benefits of the specific strain L. Reuteri MM4-1A in reducing behavioral symptoms of autism. We hypothesized that L. Reuteri MM4-1A may also favor social behaviors of autistic children. Moreover, we hypothesized that this specific probiotic improves social behavior by modifying gut microbiota composition and consequent immune response to gut microorganisms.

For this reason, we plan to perform 1) neuropsychiatric evaluation, 2) immunological analysis from blood samples, 3) microbiological analysis from stool, before supplementation with probiotic/placebo (time 0), and after six months of therapy.

From these analyses we will understand whether probiotic treatment is effective, and the involvement of immune system and microbiota in delineate the social behavior of children diagnosed with ASD.

Supplementation with L. Reuteri is non-invasive and no toxic therapy, and could be a treatment that significantly ameliorates the life of a person with autistic spectrum disorder. Moreover, the understanding of the role exerted by microbiota and immune system in social behavior, will be useful for for designing future therapeutic strategies aimed to implement the effect of L. Reuteri MM41-A.

Clinical Manifestations and the Intestinal Microbiome in Individuals on the Autism Spectrum with Inflammatory Bowel Diseases

Harland Winter, MD
Director, Pediatric IBD Program
Massachusetts General Hospital

Many individuals with an autism spectrum disorder (ASD) have comorbid conditions that impact not only on their quality of life,
but also on longevity. Deaths from comorbid gastrointestinal disorders in individuals with ASD are over 40 times higher than
neurotypical peers. Furthermore, unrecognized clinical presentations of underlying medical conditions may result in delayed
diagnosis.

Specific aims:
(1) To characterize the clinical presentation, response to therapy and outcomes of individuals with ASD who have Crohn’s
disease or ulcerative colitis;
(2) To describe the mucosal associated microbiome in individuals with ASD and Crohn’s disease/ulcerative colitis;
(3) To continue to develop the biorepository as a resource for investigators needing access to mucosal biopsies, serum, DNA,
RNA and stool from patients with and without ASD.