Hemoglobin enhances miRNA-144 expression and autophagic activation mediated inflammation of microglia via mTOR pathway.

Intracerebral hemorrhage promotes autophagic activation of microglia and enhances neuroinflammation. MiRNAs are key factors to autophagy, contributed to negatively and posttranscriptionally regulate gene expression and function. However, the specific miRNAs involved in the intracerebral hemorrhage mediated microglia autophagic activation are unidentified. In this experiment, microglia was treated with hemoglobin. And then, miRNA-144 expression, autophagic activation and inflammation of microglia were detected. In addition, the mTOR target of miRNA-144 and its regulation were identified. Our data demonstrated that hemoglobin promoted miRNA-144 expression and autophagic activation mediated inflammation. Additionally, miRNA-144 targeted mTOR by directly interacting with the 3' untranslated regions (UTRs), mutations of the binding sites abolish the miRNA-144 responsiveness. Overexpression of mTOR decreased autophagic activation and inflammation of microglia. Therefore, our results suggested that miRNA-144 contributed to hemoglobin mediated autophagic activation and inflammation of microglia via mTOR pathway. And miRNA based treatment provided novel therapeutical strategy for intracerebral hemorrhage.

C5a/C5aR Pathway Plays a Vital Role in Brain Inflammatory Injury via Initiating Fgl-2 in Intracerebral Hemorrhage.

Intracerebral hemorrhage (ICH) is a serious emergency with high mortality and morbidity. Up to date, a limited understanding of ICH pathogenesis is difficult to implement effective therapeutic strategy. Much evidence demonstrates that the complement cascade is activated after experimental ICH. However, the exact mechanism has not been well studied in ICH. In the current study, C57BL/6J mice were injected with autologous whole blood. C5a/C5aR levels, microglia infiltration, inflammatory cytokine, and fibrinogen-like protein 2 (Fgl-2) expression in the perihematomal region were analyzed following ICH. In addition, brain water content and neurological dysfunction were detected following ICH. Our data demonstrated that ICH induced complement activation, along with an increase of C5a/C5aR levels, microglia infiltration, and inflammatory cytokine levels. However, C5aR-/- mice exhibited significant attenuation of inflammatory reaction, accompanied by a remarkable reduction of Fgl-2, brain water content, and neurological dysfunction. Furthermore, inhibiting extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 efficiently inhibited C5a-mediated Fgl-2 production following ICH. Taken together, these data suggest that C5a/C5aR plays a vital role in the ICH-induced inflammatory damage via Fgl-2, and ERK1/2 and p38 pathways also are involved in the pathogenesis of ICH. Therefore, inhibition of C5a/C5aR activation might enlarge our insights in ICH therapy.

A novel nanoparticle containing MOG peptide with BTLA induces T cell tolerance and prevents multiple sclerosis.

Accumulative evidence demonstrates that multiple sclerosis (MS) is caused by activation of myelin Ag-reactive CD4+ T cells. Therefore, the CD4+ T cells specific for myelin Ag may be the important therapeutical target of MS. The novel coinhibitory receptor B and T lymphocyte attenuator (BTLA) may have a regulatory role in maintaining peripheral tolerance, however, its role in MS is still unknown. In this study, a novel nanoparticle containing MOG peptide with BTLA was designed and transduced into dendritic cells (DCs), and MOG peptide-induced EAE mice were administrated with the genetically modified DCs in vivo. The results demonstrated that modified DCs significantly enhanced the proportion of Foxp3+ CD4+ regulatory T cells, increased IL-10 and TGF-ß cytokine secretion, while decreased IL-2 and IFN-γ cytokine secretion. Furthermore, modified DCs supressed the CD4+ T cell response to MOG, cell infiltration into spinal cord, and the severity of EAE. In contrast, immune response to irrelevant exogenous Ag was not impaired by treatment with modified DCs. These findings suggested that DCs transduced with nanoparticle could induce specific CD4+ T-cells tolerance, which provided a promising therapeutic means to negatively manipulate immune response for autoimmune diseases without inhibition of the immune response to irrelevant Ag.