Project description:Objective: Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS), characterized by a global increasing incidence driven by relapsing-remitting disease in females. p38 MAP kinase (MAPK) has been described as a key regulator of inflammatory responses in autoimmunity, but its role in the sexual dimorphism in MS or MS models remains unexplored. Methods: Toward this end, we used experimental autoimmune encephalomyelitis (EAE), the principal animal model of MS, combined with pharmacologic and genetic inhibition of p38 MAPK activity and transcriptomic analyses. Results: Pharmacologic inhibition of p38 MAPK selectively ameliorated EAE in female mice. Conditional deletion studies demonstrated that p38M-NM-1 signaling in macrophages/myeloid cells, but not T cells or dendritic cells, recapitulated this sexual dimorphism. Analysis of CNS inflammatory infiltrates showed that female, but not male mice lacking p38M-NM-1 in myeloid cells exhibited reduced immune cell activation compared with controls, while peripheral T cell priming was unaffected in both sexes. Transcriptomic analyses of myeloid cells revealed differences in p38M-NM-1-controlled transcripts comprising female- and male-specific gene modules, with greater p38M-NM-1 dependence of pro-inflammatory gene expression in females. Interpretation: Our findings demonstrate a key role for p38M-NM-1 in myeloid cells in CNS autoimmunity and uncover important molecular mechanisms underlying sex differences in disease pathogenesis. Taken together, our results suggest that the p38 MAPK signaling pathway represents a novel target for much needed disease modifying therapies for MS WT vs. p38alphaCKO macrophages, male vs. female
Project description:Objective: Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS), characterized by a global increasing incidence driven by relapsing-remitting disease in females. p38 MAP kinase (MAPK) has been described as a key regulator of inflammatory responses in autoimmunity, but its role in the sexual dimorphism in MS or MS models remains unexplored. Methods: Toward this end, we used experimental autoimmune encephalomyelitis (EAE), the principal animal model of MS, combined with pharmacologic and genetic inhibition of p38 MAPK activity and transcriptomic analyses. Results: Pharmacologic inhibition of p38 MAPK selectively ameliorated EAE in female mice. Conditional deletion studies demonstrated that p38α signaling in macrophages/myeloid cells, but not T cells or dendritic cells, recapitulated this sexual dimorphism. Analysis of CNS inflammatory infiltrates showed that female, but not male mice lacking p38α in myeloid cells exhibited reduced immune cell activation compared with controls, while peripheral T cell priming was unaffected in both sexes. Transcriptomic analyses of myeloid cells revealed differences in p38α-controlled transcripts comprising female- and male-specific gene modules, with greater p38α dependence of pro-inflammatory gene expression in females. Interpretation: Our findings demonstrate a key role for p38α in myeloid cells in CNS autoimmunity and uncover important molecular mechanisms underlying sex differences in disease pathogenesis. Taken together, our results suggest that the p38 MAPK signaling pathway represents a novel target for much needed disease modifying therapies for MS
Project description:p38 MAP kinase signaling in microglia plays a sex-specific protective role in CNS autoimmunity and regulates microglial transcriptional states
Project description:p38 MAP kinase signaling in microglia plays a sex-specific protective role in CNS autoimmunity and regulates microglial transcriptional states
Project description:p38 MAP kinase signaling in microglia plays a sex-specific protective role in CNS autoimmunity and regulates microglial transcriptional states [female]
Project description:p38 MAP kinase signaling in microglia plays a sex-specific protective role in CNS autoimmunity and regulates microglial transcriptional states [male]
Project description:sex-specific role of p38-MAPK in EAE is regulated by estrogen receptor alpha; Biological sex is a critical factor in regulating immune function. A striking example of this is the higher prevalence of autoimmune diseases such as multiple sclerosis (MS) and lupus in females compared to males. While many studies have implicated the role of sex hormones such as estrogens and androgens in these sex differences, surprisingly little is known about other molecular pathways that underlie sex differences or interact with sex hormones. We have previously shown that conditional ablation of p38α MAP kinase signaling in myeloid cells (p38αCKO) was protective in a mouse model of MS, experimental autoimmune encephalomyelitis (EAE), in female but not male mice. This sex difference was dependent on the presence of sex hormones, leading us to hypothesize that the pathogenic function of p38α in EAE depends on estrogen signaling via one of the two nuclear estrogen receptors, encoded by Esr1 and Esr2. To test this hypothesis, we performed experiments with p38αCKO macrophages, which demonstrated that the effects of estradiol and p38α were independent of one another in vitro. Since many sex hormone effects are lost in vitro, we generated p38αCKO mice lacking either Esr1 or Esr2, and evaluated their EAE susceptibility in vivo. Myeloid-specific deletion of Esr1 abrogated protection in p38αCKO females, although global deletion of Esr1 and Esr2 did not. Moreover, global or myeloid-specific disruption of Esr1 unexpectedly promoted protection from EAE in p38αCKO males. Mechanistically, Esr1 deletion resulted in partial reprogramming of p38α-dependent transcriptional modules in male macrophages, in particular those regulated by TGFβ, BRD4, and SMARCA4. These results demonstrate that estrogen signaling in myeloid cells plays an important sex-specific role in programming their dependence on specific intracellular signaling pathways in the context of autoimmune disease pathogenesis, suggesting potential avenues for sex-specific therapeutics or combinatorial approaches for the treatment of such diseases.
Project description:Highly pathogenic avian influenza viruses (HPAIV) induce severe inflammation in poultry and men. There is still an ongoing threat that these viruses may acquire the capability to freely spread as novel pandemic virus strains that may cause major morbidity and mortality. One characteristic of HPAIV infections is the induction of a cytokine burst that strongly contributes to viral pathogenicity. It has been suggested, that this cytokine overexpression is an intrinsic feature of infected cells and involves hyperinduction of p38 mitogen activated protein kinase (MAPK). Here we investigate the role of MAPK p38 signaling in the antiviral response against HPAIV in mice as well as in endothelial cells, the latter a primary source for cytokines during systemic infections. Global gene expression profiling of HPAIV infected endothelial cells in the presence of the MAP kinase p38-specific inhibitor SB202190 revealed, that inhibition of MAPK p38 leads to reduced expression of interferon (IFN) and other cytokines after A/Thailand/1(KAN-1)/2004 (H5N1) and A/FPV/Bratislava/79 (H7N7) infection. Furthermore, the expression of interferon stimulated genes (ISGs) after treatment with IFN or conditioned media from HPAIV infected cells was decreased when the target cells were preincubated with SB202190. Finally, promoter analysis confirmed a direct impact of p38 MAPK on the IFN-enhanceosome and ISG-promoter activity. In vivo inhibition of MAP kinase p38 greatly diminishes virus induced cytokine expression concomitant with reduced viral titers, thereby protecting mice from lethal infection. These observations show, that MAPK p38 acts on two levels of the antiviral IFN response: Initially the kinase regulates IFN induction and at a later stage MAPK p38 controls IFN signaling and thereby expression of IFN-stimulated genes. Thus, inhibition of MAP kinase p38 may be an antiviral strategy that significantly protects mice from lethal influenza via suppression of overshooting cytokine expression. HUVEC were infected with FPV in the presence or absence of a p38 MAP kinase inhibitor
Project description:Mitogen-activated protein kinases (MAPKs) regulate cardiomyocyte growth and apoptosis in response to extracellular stimulation, but the downstream effectors that mediate their pathophysiological effects remain poorly understood. We determined the targets and role of p38 MAPK in the heart in vivo by using local adenovirus-mediated gene transfer of constitutively active upstream kinase mitogen-activated protein kinase kinase 3b (MKK3bE) and wild-type p38α in rats. DNA microarray analysis of animals with cardiac-specific overexpression of p38 MAPK revealed that 264 genes were upregulated more than 2-fold including multiple genes controlling cell division, cell signaling, inflammation, adhesion and transcription. Several previously unknown p38 target genes were found. Using gel mobility shift assays we identified several cardiac transcription factors that were directly activated by p38 MAPK. Finally, we determined the functional significance of the altered cardiac gene expression profile by histological analysis and echocardiographic measurements, which indicated that p38 MAPK overexpression induced gene expression results in cell proliferation, myocardial inflammation and fibrosis. In conclusion, we defined the novel target genes and transcription factors as well as the functional effects of p38 MAPK in the heart. Expression profiling of p38 MAPK overexpression identified cell cycle regulatory and inflammatory genes critical for pathological processes in the adult heart. Experiment Overall Design: Left ventricular gene expression profiles three days after MKK3bE + WT p38α gene transfer were compared with those of Lac Z âtreated animals by screening Affymetrix Rat Expression Set 230_2.0 Arrays (there are 5 samples in both group).