Reduced serum levels of pro-inflammatory chemokines in fragile X syndrome

Hippocampal Upregulation of Complement Component C3 in Response to Lipopolysaccharide Stimuli in a Model of Fragile-X Syndrome

The complement system is part of the innate immune system and has been shown to be altered in autism spectrum disorder (ASD). Fragile-X syndrome (FXS) is the main genetic cause of ASD and studies suggest a dysregulation in the immune system in patients with the disorder. To assess if an animal model of FXS presents with altered complement signaling, we treated male Fmr1 knockout (KO) mice with lipopolysaccharide (LPS) and collected the hippocampus 24 h later. Assessment of the expression of the complement genes C1q, C3, and C4 identified the upregulation of C3 in both wild-type (WT) and knockout mice. Levels of C3 also increased in both genotypes. Analysis of the correlation between the expression of C3 and the cytokines IL-6, IL-1β, and TNF-α identified a different relationship between the expression of the genes in Fmr1 KO when compared to WT mice. Our findings did not support our initial hypotheses that the lack of the FMR1 gene would alter complement system signaling, and that the induction of the complement system in response to LPS in Fmr1 KO mice differed from wild-type conspecifics.

Dysregulation of immune and metabolism pathways in maternal immune activation induces an increased risk of autism spectrum disorders

AIMS

Maternal immune activation (MIA) via infection during pregnancy is known to be an environmental risk factor for neurodevelopmental disorders and the development of autism spectrum disorders (ASD) in the offspring, but it still remains elusive that the molecular relevance between infection-induced abnormal neurodevelopmental events and an increased risk for ASD development.

MAIN METHODS

Fully considering the extremely high genetic heterogeneity of ASD and the universality of risk-gene with minimal effect-sizes, the gene and pathway-based association analysis was performed with the transcriptomic and DNA methylation landscapes of temporal human embryonic brain development and ASD, and the time-course transcriptional profiling of MIA. We conducted the transcriptional profiling of mouse abnormal neurodevelopment two days following induced MIA via LPS injection at E10.5.

KEY FINDINGS

A novel evidence was proved that illustrated altering four immune and metabolism-related risk pathways, including starch and sucrose metabolism, ribosome, protein processing in endoplasmic reticulum, and retrograde endocannabinoid signaling pathway, which were prominent involvement in the process of MIA regulating abnormal fetal brain development to induce an increased risk of ASD. Here, we have observed that almost all key genes within these risk pathways are significantly differentially expressed at embryonic days (E) 10.5-12.5, which is considered to be the optimal coincidence window of mouse embryonic brain development to study the intimate association between MIA and ASD using mouse animal models.

SIGNIFICANCE

There search establishes that MIA causes dysregulation of immune and metabolic pathways, which leads to abnormal embryonic neurodevelopment, thus promoting development of ASD symptoms in offspring.

The diagnostic importance of multiple cytokines in adult hemophagocytic lymphohistiocytosis

BACKGROUND

Hemophagocytic lymphohistiocytosis (HLH) is a category of immunological illnesses that cause out-of-control T cells and macrophages to release life-threatening cytokines. The HLH-2004 diagnostic criteria are the gold standard for HLH diagnosis, but there is a need to investigate the usefulness of various cytokines for HLH diagnosis.

METHODS

Patients admitted to Beijing Friendship Hospital of Capital Medical University from January 2016 to December 2020 were included in this retrospective study, with 166 patients with confirmed HLH and 142 febrile patients requiring differential diagnosis completing the sum. Multiplex cytokine assays using multifactor liquid phase microarray technology-based multifactor liquid phase microarray technology were used to detect 33 cytokines. Twenty-eight cytokines detected using the Luminex analytical platform technology were ultimately included in the analysis.

RESULTS

Interleukin-1 receptor antagonist (IL-1 RA), IL-18, interferon-γ (IFN-γ), and interferon-induced protein 10 (IP-10) regulated upon activation normal T cell expressed and secreted (RANTES), eotaxin, growth-related oncogene α (GRO-α), and macrophage inflammatory protein-1 α (MIP-1α) were higher in the HLH group than in the non-HLH group, and the differences were statistically significant. Among them, the area under the curve (AUC) for IL-18 for HLH diagnosis was reported for the first time as 82.69%, with a sensitivity of 76.32% and a specificity of 79.61%; the AUC of IL-1 RA was 72.34%, with a sensitivity of 62.71% and a specificity of 75.97%; and the AUC of IP-10 was 71.73%, with a sensitivity of 60.14% and a specificity of 75.15%. Moreover, the AUC of the combined diagnostic tests for IL-1 RA, IL-18, IFN-γ, IP-10, and RANTES was 99.6%, with a sensitivity of 95.8% and a specificity of 98.6%.

CONCLUSION

Our study concluded that multiple cytokines are valid biological markers for the diagnosis of HLH. The findings of this study remain to be validated in an external dataset.

Associations and Disease–Disease Interactions of COVID-19 with Congenital and Genetic Disorders: A Comprehensive Review

Since December 2019, the COVID-19 pandemic, which originated in Wuhan, China, has resulted in over six million deaths worldwide. Millions of people who survived this SARS-CoV-2 infection show a number of post-COVID complications. Although, the comorbid conditions and post-COVID complexities are to some extent well reviewed and known, the impact of COVID-19 on pre-existing congenital anomalies and genetic diseases are only documented in isolated case reports and case series, so far. In the present review, we analyzed the PubMed indexed literature published between December 2019 and January 2022 to understand this relationship from various points of view, such as susceptibility, severity and heritability. Based on our knowledge, this is the first comprehensive review on COVID-19 and its associations with various congenital anomalies and genetic diseases. According to reported studies, some congenital disorders present high-risk for developing severe COVID-19 since these disorders already include some comorbidities related to the structure and function of the respiratory and cardiovascular systems, leading to severe pneumonia. Other congenital disorders rather cause psychological burdens to patients and are not considered high-risk for the development of severe COVID-19 infection.

Disrupted Association of Sensory Neurons With Enveloping Satellite Glial Cells in Fragile X Mouse Model

Among most prevalent deficits in individuals with Fragile X syndrome (FXS) is hypersensitivity to sensory stimuli and somatosensory alterations. Whether dysfunction in peripheral sensory system contributes to these deficits remains poorly understood. Satellite glial cells (SGCs), which envelop sensory neuron soma, play critical roles in regulating neuronal function and excitability. The potential contributions of SGCs to sensory deficits in FXS remain unexplored. Here we found major structural defects in sensory neuron-SGC association in the dorsal root ganglia (DRG), manifested by aberrant covering of the neuron and gaps between SGCs and the neuron along their contact surface. Single-cell RNAseq analyses demonstrated transcriptional changes in both neurons and SGCs, indicative of defects in neuronal maturation and altered SGC vesicular secretion. We validated these changes using fluorescence microscopy, qPCR, and high-resolution transmission electron microscopy (TEM) in combination with computational analyses using deep learning networks. These results revealed a disrupted neuron-glia association at the structural and functional levels. Given the well-established role for SGCs in regulating sensory neuron function, altered neuron-glia association may contribute to sensory deficits in FXS.

An "Omic" Overview of Fragile X Syndrome

Fragile X syndrome (FXS) is a neurodevelopmental disorder associated with a wide range of cognitive, behavioral and medical problems. It arises from the silencing of the fragile X mental retardation 1 (FMR1) gene and, consequently, in the absence of its encoded protein, FMRP (fragile X mental retardation protein). FMRP is a ubiquitously expressed and multifunctional RNA-binding protein, primarily considered as a translational regulator. Pre-clinical studies of the past two decades have therefore focused on this function to relate FMRP's absence to the molecular mechanisms underlying FXS physiopathology. Based on these data, successful pharmacological strategies were developed to rescue fragile X phenotype in animal models. Unfortunately, these results did not translate into humans as clinical trials using same therapeutic approaches did not reach the expected outcomes. These failures highlight the need to put into perspective the different functions of FMRP in order to get a more comprehensive understanding of FXS pathophysiology. This work presents a review of FMRP's involvement on noteworthy molecular mechanisms that may ultimately contribute to various biochemical alterations composing the fragile X phenotype.

COVID-19 Infection in a Patient With Fragile-X Syndrome

Over the past several months we have learned about how pre-existent comorbidities may influence the outcome of patients infected with the coronavirus disease 2019 (COVID-19), with diabetes mellitus and obesity being commonly reported in association with increased mortality among these patients. In this report, the authors explore the case of a patient with Fragile-X Syndrome (FXS) who developed pneumonia due to COVID-19. FXS is an inherited cause of intellectual disability with potential neurologic and physiologic sequelae. In this narrative, we aim to describe how FXS may potentially play a role in the clinical course of patients with COVID-19.

Repurposing Fragile X Drugs to Inhibit SARS-CoV-2 Viral Reproduction

The COVID-19 pandemic is a global health crisis that requires the application of interdisciplinary research to address numerous knowledge gaps including molecular strategies to prevent viral reproduction in affected individuals. In response to the Frontiers Research Topic, "Coronavirus disease (COVID-19): Pathophysiology, Epidemiology, Clinical Management, and Public Health Response," this Hypothesis article proposes a novel therapeutic strategy to repurpose metabotropic glutamate 5 receptor (mGluR₅) inhibitors to interfere with viral hijacking of the host protein synthesis machinery. We review pertinent background on SARS-CoV-2, fragile X syndrome (FXS) and metabotropic glutamate receptor 5 (mGluR₅) and provide a mechanistic-based hypothesis and preliminary data to support testing mGluR₅ inhibitors in COVID-19 research.

Potential Cytokine Biomarkers in Intellectual Disability

Intellectual disability (ID), previously called mental retardation, is the most common neurodevelopmental disorder characterized by life-long intellectual and adaptive functioning impairments that have an impact on individuals, families, and society. Its prevalence is estimated to 3% of the general population and its etiology is still insufficiently understood. Besides the involvement of genetic and environmental factors, immunological dysfunctions have been also suggested to contribute to the pathophysiology of ID. Over the years, immune biomarkers related to ID have gained significant attention and researchers have begun to look at possible cytokine profiles in individuals suffered from this disorder. In fact, in addition to playing crucial physiological roles in the majority of normal neurodevelopmental processes, cytokines exert an important role in neuroinflammation under pathological conditions, and interactions between the immune system and central nervous system have long been under investigation. Cytokine levels imbalance has been reported associated with some behavioral characteristics and the onset of some syndromic forms of ID. In this review, we will focus on immunological biomarkers, especially the cytokine profiles that have been identified in people with ID. Thus, data reported and discussed in the present paper may provide additional information to start further studies and to plan strategies for early identification and managing of ID.