Nrdp1-mediated Macrophage Phenotypic Regulation Promotes Functional Recovery in Mice with Mild Neurological Impairment after Intracerebral Hemorrhage.

Neuregulin receptor degradation protein 1 (Nrdp1) is a ring finger E3 ubiquitin ligase involved in some inflammation through ubiquitination, including macrophage polarization following cerebral hemorrhage. However, there is limited understanding regarding the mechanisms through which Nrdp1 modulates macrophage polarization and the potential impact of this modulation on neurological function. Using stereotactic injection and adenoviral transfection techniques, the corresponding animal models were constructed through injecting adenovirus, saline, or blood into the mouse striatum at different periods of time in this research. The alteration in the ratio of various M1/M2 phenotype-associated markers (e.g., CD86, CD206, IL-6, IL-10, etc.) was evaluated through immunohistochemistry, immunofluorescence, western blotting, and elisa assays. Additionally, neurological function scores and behavioral tests were utilized to evaluate changes in neurological function in mice after cerebral hemorrhage. Our results show that overexpression of Nrdp1 promotes the expression of a variety of M2 macrophage-associated markers and enhance transcriptional activity of arginase-1 (Arg1) protein through ubiquitination for early regulation M2 macrophage polarization. Additionally, Nrdp1 promotes hematoma absorption, increases IL-10 expression, inhibits inducible nitric oxide synthase (iNOS), IL-6, and TNF-α production, alleviates neurological impairment and brain edema, and accelerates functional recovery. These findings suggest that modulating macrophage polarization through Nrdp1 could be a therapeutic strategy for neurofunctional impairment in cerebral 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.

Toll-like receptor-4-mediated autophagy contributes to microglial activation and inflammatory injury in mouse models of intracerebral haemorrhage.

AIMS: Much evidence demonstrates that Toll-like receptor-4 (TLR4)-mediated microglial activation is an important contributor to the inflammatory injury in intracerebral haemorrhage (ICH). However, the exact mechanism of TLR4-mediated microglial activation induced by ICH is not clear. In addition, microglial autophagy is involved other forms of nervous system injury. To explore the relationship between TLR4 and autophagy, we investigated the role of TLR4-mediated microglial autophagy and inflammation in ICH. METHODS: We detected TLR4 expression, autophagy and inflammation of microglia treated with lysed erythrocytes in vitro, and observed the cerebral water content and neurological deficit of ICH mice [TLR4-/- and wild type (WT)] in vivo. RESULTS: We found that lysed erythrocyte treated microglia (TLR4-/-) had reduced autophagy and inflammation compared with microglia (WT) in vitro. ICH mice (TLR4-/-) had reduced water content and neurological injury compared with ICH mice (WT). The autophagy inhibitor (3-methyladenine) decreased microglial activation and inflammatory injury due to lysed erythrocyte treatment, and improved the neurological function of ICH mice. CONCLUSIONS: Taken together, these data suggested that TLR4 induced autophagy contributed to the microglial activation and inflammatory injury and might provide novel therapeutic interventions for ICH.

Regulatory T cells inhibit microglia activation and protect against inflammatory injury in intracerebral hemorrhage.

Numerous evidence demonstrate that microglia mediated inflammatory injury plays a critical role in intracerebral hemorrhage (ICH). Therefore, the way to inhibit the inflammatory response is greatly needed. Treg cells have been shown to play a critical role in immunologic self-tolerance as well as anti-tumor immune responses and transplantation. In the current study, we transfered Treg cells in the ICH model, and investigated the effect. The cytokines of microglia were measured by ELISA, JNK/ERK and NF-κB were measured by Western blot and EMSA (Electrophoretic Mobility Shift Assay), animal behavior was evaluated by animal behavioristics. We found that Treg cells could inhibit microglia mediated inflammatory response through NF-κB activation via the JNK/ERK pathway in vitro, and improve neurological function in vivo. Our findings suggest that Treg cells could suppress inflammatory injury and represent a novel cell-based therapeutical strategy in ICH.

Dendritic cells transduced with CPEB4 induced antitumor immune response.

Much evidence leads to the exploration of immunologic approaches for eliminating tumor cells. Cytoplasmic polyadenylation element binding protein 4 (CPEB4) is considered to be a novel therapeutical target for glioblastoma. In this study, we transduced DCs with CPEB4 to explore the immune response in vivo. We found that DCs transduced with recombinant adenovirus encoding CPEB4 could induce specific cytotoxic T lymphocytes (CTLs) to lyse glioma cells and augment the number of IFN-γ secreting T-cells in mice. In addition, the modified DCs could effectively protect mice from lethal challenges against glioma cells, reduce tumor growth and increase the mice life span. These results suggest that the DC transduced with CPEB4 may induce anti-tumor immunity against glioma cells and might be used as an efficient tumor vaccine in clinical applications.

Microglial activation with reduction in autophagy limits white matter lesions and improves cognitive defects during cerebral hypoperfusion.

Microglial activation plays a vital role in the pathogenesis of white matter lesions (WMLs) during chronic cerebral hypo perfusion. Autophagy has been associated with both microglia survival and cell death. Yet, the role of autophagy during microglial activation in chronic cerebral ischemia is still unknown. We used a chronic cerebral hypoperfusion model by permanent stenosis of bilateral common carotid artery in mice to study microglial activation and autophagy. However, the autophagy inhibitor (3-methyladenine) could attenuate microglial autophagic activation, decrease white matter lesions, and improve working memory during chronic cerebral hypoperfusion in mice. In conclusion, chronic cerebral hypoperfusion that leads to microglial activation and autophagy induction exacerbates white matter lesions and cognitive deficits in mice. Our findings represent a potential novel target for chronic cerebral hypoperfusion 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.

Isthmin inhibits glioma growth through antiangiogenesis in vivo.

Among glioma treatment strategies, antiangiogenesis emerges as a meaningful and feasible treatment approach for inducing long-term survival. Isthmin is a gene highly expressed in the isthmus of the midbrain-hindbrain organizer in Xenopus, and has recently been identified as a novel angiogenesis inhibitor. However, the potential of isthmin on the glioma angiogenesis has not been well studied. In the present study, we demonstrated that the recombinant adenovirus isthmin (Ad-isthmin) could inhibit VEGF-stimulated endothelial cell proliferation and induce apoptosis through a caspase-dependent pathway. In addition, Ad-isthmin significantly suppressed glioma growth through antiangiogenesis without apparent side effects. Taken together, our results demonstrated that isthmin could act as a novel angiogenesis inhibitor and might be utilized in the glioma antiangiogenesis therapy.