Prenatal interleukin 6 elevation increases glutamatergic synapse density and disrupts hippocampal connectivity in offspring

The AHNAK induces increased IL-6 production in CD4+ T cells and serves as a potential diagnostic biomarker for recurrent pregnancy loss

Disorganized maternal-fetal immune tolerance contributes to the occurrence of unexplained recurrent pregnancy loss (RPL). AHNAK is a scaffolding protein participating in the regulation of Ca2+ entry into T cells and the pathophysiology of diverse diseases. We performed differential gene expression analysis in decidual immune cells (DICs) isolated from three patients with RPL and from three healthy controls via RNA-sequencing (RNA-seq), which revealed 407 differentially expressed genes (DEGs). Among these DEGs, we underscored the clinical significance of elevated AHNAK mRNA and protein levels in DICs, peripheral blood mononuclear cells (PBMCs), and decidua of the patients with RPL, suggesting its potential use as a biomarker for the diagnosis of RPL. Especially, the ratios of decidual and blood AHNAK+CD4+ T cells in the CD4+ T cell population were significantly increased in patients with RPL, and the loss of AHNAK was further shown to inhibit interleukin (IL)-6 secretion in the CD4+ Jurkat cell line. Similar patterns were also observed in the clinical decidual and blood specimens. We uncovered that the AHNAK+CD4+ T cells could secrete more IL-6 than that the corresponding AHNAK-CD4+ T cells. Moreover, the frequencies of decidual and blood IL-6+CD4+ T cells in the CD4+ T-cell population were also increased in patients with RPL and showed significant positive correlations with the frequencies of AHNAK+CD4+ T cells. Our findings suggest that the elevated AHNAK expressed by CD4+ T cells may be involved in the immune dysregulation of RPL by increasing IL-6 production, illustrating its potential as a novel intervention target for RPL.

Systemic inflammatory regulators and 7 major psychiatric disorders: A two-sample Mendelian randomization study

Systemic inflammation has been thought to play a considerable part in psychiatric disorders. However, the causal relationships between systemic inflammation and psychiatric disorders and the directions of the causal effects remain elusive and need further investigation. By leveraging the summary statistics of genome-wide association studies, the standard inverse variance weighted method was applied to assess the causal associations among 41 systemic inflammatory regulators and 7 major psychiatric disorders, including attention-deficit/hyperactivity disorder (ADHD), anorexia nervosa (AN), autism spectrum disorder (ASD), bipolar disorder (BIP), major depression disorder (MDD), obsessive-compulsive disorder (OCD), and schizophrenia (SCZ), within a two-sample bidirectional Mendelian randomization analysis. Additionally, the weighted median test and the Mendelian randomization pleiotropy residual sum and outlier test were conducted for sensitivity analyses. The results suggested a total of 15 unique systemic inflammatory regulators might be causally associated with disease risk, including 2 for ADHD, 4 for AN, 2 for ASD, 2 for MDD, 2 for OCD, and 5 for SCZ. Among them, the genetically predicted concentration of basic fibroblast growth factor was significantly related to AN at the Bonferroni-corrected threshold (Odds ratio = 0.403, 95% confidence interval = (0.261, 0.622), P = 4.03 × 10^-5). Furthermore, the concentrations of 9 systemic inflammatory regulators might be influenced by neuropsychiatric disorders, including 2 by ADHD, 2 by BIP, 3 by MDD, and 2 by SCZ, and the causal effects of ASD, AN, and OCD need to be further assessed when more significant genetic variants are identified in the future. Overall, this study provides additional insights into the relationships between systemic inflammation and psychiatric disorders and may provide new clues regarding the aetiology, diagnosis and treatment of psychiatric disorders.

JUN and PDGFRA as Crucial Candidate Genes for Childhood Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder, characterized by marked genetic heterogeneity. In this study, two independent microarray datasets of cerebellum of ASD were integrative analyzed by NetworkAnalyst to screen candidate crucial genes. NetworkAnalyst identified two up-regulated genes, Jun proto-oncogene (JUN) and platelet derived growth factor receptor alpha (PDGFRA), as the most crucial genes in cerebellum of ASD patients. Based on KEGG pathway database, genes associated with JUN in the cerebellum highlight the pathways of Th17 cell differentiation and Th1 and Th2 cell differentiation. Genes associated with PDGFRA in the cerebellum were found enriched in pathways in EGFR tyrosine kinase inhibitor resistance and Rap1 signaling pathway. Analyzing all differentially expressed genes (DEGs) from the two datasets, Gene Set Enrichment Analysis (GSEA) brought out IL17 signaling pathway, which is related to the expression of JUN and PDGFRA. The ImmuCellAI found the elevated expression of JUN and PDGFRA correlating with increased Th17 and monocytes suggests JUN and PDGFRA may regulate Th17 cell activation and monocytes infiltrating. Mice model of maternal immune activation demonstrated that JUN and PDGFRA are up-regulated and related to the ASD-like behaviors that provide insights into the molecular mechanisms underlying the altered IL17 signaling pathway in ASD and may enable novel therapeutic strategies.

Maternal inflammation and its ramifications on fetal neurodevelopment

Exposure to heightened inflammation in pregnancy caused by infections or other inflammatory insults has been associated with the onset of neurodevelopmental and psychiatric disorders in children. Rodent models have provided unique insights into how this maternal immune activation (MIA) disrupts brain development. Here, we discuss the key immune factors involved, highlight recent advances in determining the molecular and cellular pathways of MIA, and review how the maternal immune system affects fetal development. We also examine the roles of microbiomes in shaping maternal immune function and the development of autism-like phenotypes. A comprehensive understanding of the gut bacteria-immune-neuro interaction in MIA is essential for developing diagnostic and therapeutic measures for high-risk pregnant women and identifying targets for treating inflammation-induced neurodevelopmental disorders.

Establishment of tissue-resident immune populations in the fetus

The immune system establishes during the prenatal period from distinct waves of stem and progenitor cells and continuously adapts to the needs and challenges of early postnatal and adult life. Fetal immune development not only lays the foundation for postnatal immunity but establishes functional populations of tissue-resident immune cells that are instrumental for fetal immune responses amidst organ growth and maturation. This review aims to discuss current knowledge about the development and function of tissue-resident immune populations during fetal life, focusing on the brain, lung, and gastrointestinal tract as sites with distinct developmental trajectories. While recent progress using system-level approaches has shed light on the fetal immune landscape, further work is required to describe precise roles of prenatal immune populations and their migration and adaptation to respective organ environments. Defining points of prenatal susceptibility to environmental challenges will support the search for potential therapeutic targets to positively impact postnatal health.

IL-6 boosts synaptogenesis STAT!

Maternal infection during pregnancy increases the offspring's risk of developing neurodevelopmental disorders. While IL-6 is involved, the mechanism by which IL-6 and other cytokines affect developing neural circuits is unknown. In this issue of Immunity, Mirabella et al. (2021) show that the pro-inflammatory cytokine IL-6 specifically increases synaptogenesis in immature excitatory neurons through downstream neuronal STAT3-dependent transcriptional regulation of Rgs4.