Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0014070 (encephalomyelitis)
 13,017 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Bphs controls Bordetella pertussis toxin (PTX)-induced vasoactive amine sensitization elicited by histamine (VAASH) and has an established role in autoimmunity. We report that congenic mapping links Bphs to the histamine H1 receptor gene (Hrh1/H1R) and that H1R differs at three amino acid residues in VAASH-susceptible and -resistant mice. Hrh1-/- mice are protected from VAASH, which can be restored by genetic complementation with a susceptible Bphs/Hrh1 allele, and experimental allergic encephalomyelitis and autoimmune orchitis due to immune deviation. Thus, natural alleles of Hrh1 control both the autoimmune T cell and vascular responses regulated by histamine after PTX sensitization.
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PMID:Identification of Bphs, an autoimmune disease locus, as histamine receptor H1. 1214 41

Analysis of mRNA from multiple sclerosis lesions revealed increased amounts of transcripts for several genes encoding molecules traditionally associated with allergic responses, including prostaglandin D synthase, histamine receptor type 1 (H1R), platelet activating factor receptor, Ig Fc epsilon receptor 1 (Fc epsilon RI), and tryptase. We now demonstrate that, in the animal model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE), mediated by T helper 1 (Th1) T cells, histamine receptor 1 and 2 (H1R and H2R) are present on inflammatory cells in brain lesions. Th1 cells reactive to myelin proteolipid protein expressed more H1R and less H2R than Th2 cells. Pyrilamine, an H1R antagonist, blocked EAE, and the platelet activating factor receptor antagonist CV6209 reduced the severity of EAE. EAE severity was also decreased in mice with disruption of the genes encoding Ig Fc gamma RIII or both Fc gamma RIII and Fc epsilon RI. Prostaglandin D synthase and tryptase transcripts were elevated in EAE brain. Taken together, these data reveal extensive involvement of elements of the immune response associated with allergy in autoimmune demyelination. The pathogenesis of demyelination must now be viewed as encompassing elements of both Th1 responses and "allergic" responses.
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PMID:Multiple elements of the allergic arm of the immune response modulate autoimmune demyelination. 1257 52

Histamine, a biogenic amine with both neurotransmitter and vasoactive properties, is well recognized as an immunomodulatory agent in allergic and inflammatory reactions. It also plays a regulatory role in the development of antigen-specific immune responses. CD4+ T-cells from histamine H1 receptor (H1R)-deficient (H1RKO) mice produce significantly less interferon-gamma and more interleukin (IL)-4 in in vitro recall assays compared to wild-type controls. H1RKO mice are also less susceptible to acute early-phase experimental allergic encephalomyelitis indicating that H1R signaling in CD4+ T cells plays a central role in regulating pathogenic T-cell responses. In this study, we show that mice lacking histamine H2 receptor (H2RKO) are similar to H1RKO mice in that they develop encephalitogen-specific T-cell responses as assessed by proliferation and IL-2 production and present with less severe acute early-phase experimental allergic encephalomyelitis. However, unlike T cells from H1RKO mice, which exhibit a strong Th2 bias, T cells from H2RKO mice do not. Rather, they are uniquely characterized by a significant inhibition of Th1 effector cell responses. Given that both histamine and adjuvants such as pertussis toxin modulate antigen-presenting cell (APC) maturation and function, including T-cell-polarizing activity, we analyzed the cytokines/chemokines secreted by APCs from wild-type, H1RKO, and H2RKO mice. Significant differences in cytokine/chemokine production by APCs from unimmunized and immunized mice were delineated. APCs from H2RKO mice produce significantly less IL-12 and IL-6 and markedly greater amounts of MCP-1 compared to wild-type and H1RKO mice. Because MCP-1 is known to inhibit IL-12 production, the failure of H2RKO mice to generate encephalitogenic Th1 effector cell responses is consistent with inhibition of negative regulation of MCP-1 secretion by H2R signaling in APCs.
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PMID:Attenuation of Th1 effector cell responses and susceptibility to experimental allergic encephalomyelitis in histamine H2 receptor knockout mice is due to dysregulation of cytokine production by antigen-presenting cells. 1498 42

Histamine receptor H1 (H1R) is a susceptibility gene in both experimental autoimmune encephalomyelitis (EAE) and experimental autoimmune orchitis (EAO), 2 classical T cell-mediated models of organ-specific autoimmune disease. Here we showed that expression of H1R in naive CD4+ T cells was required for maximal IFN-gamma production but was dispensable for proliferation. Moreover, H1R signaling at the time of TCR ligation was required for activation of p38 MAPK, a known regulator of IFN-gamma expression. Importantly, selective reexpression of H1R in CD4+ T cells fully complemented both the IFN-gamma production and the EAE susceptibility of H1R-deficient mice. These data suggest that the presence of H1R in CD4+ T cells and its interaction with histamine regulates early TCR signals that lead to Th1 differentiation and autoimmune disease.
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PMID:Histamine receptor H1 is required for TCR-mediated p38 MAPK activation and optimal IFN-gamma production in mice. 1796 72

Disruption of the blood-brain barrier (BBB) underlies the development of experimental autoimmune encephalomyelitis (EAE) and multiple sclerosis. Environmental factors, such as Bordetella pertussis, are thought to sensitize central endothelium to biogenic amines like histamine, thereby leading to increased BBB permeability. B. pertussis-induced histamine sensitization (Bphs) is a monogenic intermediate phenotype of EAE controlled by histamine H(1) receptor (Hrh1/H(1)R). Here, we transgenically overexpressed H(1)R in endothelial cells of Hrh1-KO (H(1)RKO) mice to test the role of endothelial H(1)R directly in Bphs and EAE. Unexpectedly, transgenic H(1)RKO mice expressing endothelial H(1)R under control of the von Willebrand factor promoter (H(1)RKO-vWF(H1R) Tg) were Bphs-resistant. Moreover, H(1)RKO-vWF(H1R) Tg mice exhibited decreased BBB permeability and enhanced protection from EAE compared with H(1)RKO mice. Thus, contrary to prevailing assumptions, our results show that endothelial H(1)R expression reduces BBB permeability, suggesting that endothelial H(1)R signaling may be important in the maintenance of cerebrovascular integrity.
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PMID:Endothelial histamine H1 receptor signaling reduces blood-brain barrier permeability and susceptibility to autoimmune encephalomyelitis. 2095 10

The histamine H(1) receptor (Hrh1/H(1)R) was identified as an autoimmune disease gene in experimental allergic encephalomyelitis (EAE), the principal autoimmune model of multiple sclerosis (MS). Previously, we showed that selective re-expression of H(1)R by endothelial cells or T cells in H(1)RKO mice significantly reduced or complemented EAE severity and cytokine responses, respectively. H(1)R regulates innate immune cells, which in turn influences peripheral and central nervous system CD4(+) T cell effector responses. Therefore, we selectively re-expressed H(1)R in CD11b(+) cells of H(1)RKO mice to test the hypothesis that H(1)R signaling in these cells contributes to EAE susceptibility. We demonstrate that transgenic re-expression of H(1)R by H(1)RKO-CD11b(+) cells neither complements EAE susceptibility nor T cell cytokine responses highlighting the cell-specific effects of Hrh1 in the pathogenesis of EAE and MS, and the need for cell-specific targeting in optimizing therapeutic interventions based on such genes.
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PMID:H(1)R expression by CD11B(+) cells is not required for susceptibility to experimental allergic encephalomyelitis. 2312 73

Histamine (HA) is a key regulator of experimental allergic encephalomyelitis (EAE), the autoimmune model of multiple sclerosis. HA exerts its effects through four known G-protein-coupled receptors: H1, H2, H3, and H4 (histamine receptors; H(1-4)R). Using HR-deficient mice, our laboratory has demonstrated that H1R, H2R, H3R, and H4R play important roles in EAE pathogenesis, by regulating encephalitogenic T cell responses, cytokine production by APCs, blood-brain barrier permeability, and T regulatory cell activity, respectively. Histidine decarboxylase-deficient mice (HDCKO), which lack systemic HA, exhibit more severe EAE and increased Th1 effector cytokine production by splenocytes in response to myelin oligodendrocyte gp35-55. In an inverse approach, we tested the effect of depleting systemic canonical HA signaling on susceptibility to EAE by generating mice lacking all four known G-protein-coupled-HRs (H(1-4)RKO mice). In this article, we report that in contrast to HDCKO mice, H(1-4)RKO mice develop less severe EAE compared with wild-type animals. Furthermore, splenocytes from immunized H(1-4)RKO mice, compared with wild-type mice, produce a lower amount of Th1/Th17 effector cytokines. The opposing results seen between HDCKO and H1-4RKO mice suggest that HA may signal independently of H1-4R and support the existence of an alternative HAergic pathway in regulating EAE resistance. Understanding and exploiting this pathway has the potential to lead to new disease-modifying therapies in multiple sclerosis and other autoimmune and allergic diseases.
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PMID:Systemic lack of canonical histamine receptor signaling results in increased resistance to autoimmune encephalomyelitis. 2377 30

Peripheral immune cells are critical to the pathogenesis of neurodegenerative diseases including multiple sclerosis (MS) (Hendriks et al., 2005; Kasper and Shoemaker, 2010). However, the precise sequence of tissue events during the early asymptomatic induction phase of experimental autoimmune encephalomyelitis (EAE) pathogenesis remains poorly defined. Due to the spatial-temporal constrains of traditional methods used to study this disease, most studies had been performed in the spine during peak clinical disease; thus the debate continues as to whether tissue changes such as vessel disruption represent a cause or a byproduct of EAE pathophysiology in the cortex. Here, we provide dynamic, high-resolution information on the evolving structural and cellular processes within the gray matter of the mouse cortex during the first 12 asymptomatic days of EAE induction. We observed that transient focal vessel disruptions precede microglia activation, followed by infiltration of and directed interaction between circulating dendritic cells and T cells. Histamine antagonist minimizes but not completely ameliorates blood vessel leaks. Histamine H1 receptor blockade prevents early microglia function, resulting in subsequent reduction in immune cell accumulation, disease incidence and clinical severity.
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PMID:Focal transient CNS vessel leak provides a tissue niche for sequential immune cell accumulation during the asymptomatic phase of EAE induction. 2570 87