title: TLR3 downregulates expression of schizophrenia gene Disc1 via MYD88 to control neuronal morphology.
abstract: Viral infection during fetal or neonatal stages increases the risk of developing neuropsychiatric disorders such as schizophrenia and autism spectrum disorders. Although neurons express several key regulators of innate immunity, the role of neuronal innate immunity in psychiatric disorders is still unclear. Using cultured neurons and in vivo mouse brain studies, we show here that Toll-like receptor 3 (TLR3) acts through myeloid differentiation primary response gene 88 (MYD88) to negatively control Disrupted in schizophrenia 1 (Disc1) expression, resulting in impairment of neuronal development. Cytokines are not involved in TLR3-mediated inhibition of dendrite outgrowth. Instead, TLR3 signaling suppresses expression of several psychiatric disorder-related genes, including Disc1 The impaired dendritic arborization caused by TLR3 activation is rescued by MYD88 deficiency or DISC1 overexpression. In addition, TLR3 activation at the neonatal stage increases dendritic spine density, but narrows spine heads at postnatal day 21 (P21), suggesting a long-lasting effect of TLR3 activation on spinogenesis. Our study reveals a novel mechanism of TLR3 in regulation of dendritic morphology and provides an explanation for how environmental factors influence mental health.
authors.affiliation: Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan.
authors.forename: Chiung-Ya
authors.initials: CY
authors.lastname: Chen
authors.affiliation: Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan.
authors.forename: Hsin-Yu
authors.initials: HY
authors.lastname: Liu
authors.affiliation: Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan yph@gate.sinica.edu.tw.
authors.forename: Yi-Ping
authors.identifier: 0000-0002-0866-6275
authors.initials: YP
authors.lastname: Hsueh
mesh_terms: D000818:Animals; D015415:Biomarkers; D002460:Cell Line; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism; D003712:Dendrites / Q000235:genetics / Q000378:metabolism; D004195:Disease Models, Animal; D005786:Gene Expression Regulation; D055785:Gene Knockdown Techniques; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D009024:Morphogenesis / Q000235:genetics; D053594:Myeloid Differentiation Factor 88 / Q000235:genetics / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D012559:Schizophrenia / Q000235:genetics* / Q000378:metabolism*; D015398:Signal Transduction; D051196:Toll-Like Receptor 3 / Q000235:genetics / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D016207:Cytokines; C412476:DISC1 protein, human; D053594:Myeloid Differentiation Factor 88; D009419:Nerve Tissue Proteins; D051196:Toll-Like Receptor 3
keywords: dendritic growth; dendritic spine formation; innate immunity; neonatal infection; neural development