Enhancement of T Follicular Helper Cell-Mediated Humoral Immunity Reponses During Development of Experimental Autoimmune Myasthenia Gravis.

Myasthenia gravis (MG) is a prototypical antibody-mediated neurological autoimmune disease with the involvement of humoral immune responses in its pathogenesis. T follicular helper (Tfh) cells have been implicated in many autoimmune diseases. However, whether and how Tfh cells are involved in MG remain unclear. Here, we established and studied a widely-used and approved animal model of human MG, the rat model with acetylcholine receptor alpha (AChRα) subunit (R-AChR97-116)-induced experimental autoimmune myasthenia gravis (EAMG). This model presented mild body-weight loss 10 days after the first immunization (representing the early stage of disease) and more obvious clinical manifestations and body-weight loss 7 days after the second immunization (representing the late stage of disease). AChR-specific pre-Tfh cells and mature Tfh cells were detected in these two stages, respectively. In co-cultures of Tfh cells and B cells, the number of IgG2b-secreting B cells and the level of anti-AChR antibodies in the supernatant were higher in the cultures containing EAMG-derived Tfh cells. In immunohistochemistry and immunofluorescence assays, a substantial number of CD4+/Bcl-6+ T cells and a greater number of larger germinal centers were observed in lymph node tissues resected from EAMG rats. Based on these results, we hypothesize that an AChR-specific Tfh cell-mediated humoral immune response contributes to the development of EAMG.

MicroRNA 182 inhibits CD4+CD25+Foxp3+ Treg differentiation in experimental autoimmune encephalomyelitis.

MicroRNA 182 has been found to have a distinct contribution in the clonal expansion of activated- and functioning of specialized-helper T cells. In this study we knocked down microRNA 182 in vivo and induced experimental autoimmune encephalomyelitis (EAE) to determine the influences of microRNA 182 in the Treg cells functional specialization through Foxo1 dependent pathway in the peripheral lymphoid organs. Down-regulation of microRNA 182 significantly increased the proportions of Foxp3+ T cells in the peripheral lymph nodes and spleen. In vivo study verified a positive correlation between microRNA 182 levels and symptom severity of EAE, and a negative correlation between microRNA 182 and the transcriptional factor Foxp3. In vitro polarization study also confirmed the contribution of Foxo1 in microRNA 182 mediated down-regulation of Foxp3+ T cells. Together, our results provide evidence that during the development of EAE, microRNA 182 repressed Treg cells differentiation through the Foxo1 dependent pathway.

Effects of IL-17A on the occurrence of lung adenocarcinoma.

The relationship between IL-17A and cancer, whether beneficial or antagonistic, continues to be a controversial issue. In this study, effects of IL-17A on lung adenocarcinoma were investigated using lung cancer cell lines, 95D and 95C. In the presence or absence of IL-17A, cell proliferation and VEGF secretion were detected. Effects of IL-17A on capillary networks and process of angiogenesis were also evaluated. In vivo, the level of IL-17A was assayed in the serum of lung adenocarcinoma patients. At the same time, slices of adenocarcinoma tissue were analyzed for expression of IL-17A, its receptor (IL-17RA), VEGF, CD4(+)-IL-17A+ cells and CD8(+)-IL-17A+ cells by immunohistochemistry and immunofluorescence assays. IL-17A did not have effect on the proliferation of 95D or 95C cells, however, the elevated expression of VEGF in supernatant of 95D or 95C cells was found to be IL-17A concentration-dependent. Supernatants from 95D or 95C cells treated with IL-17A could obviously facilitate angiogenesis, compared with IL-17A absence group (P < 0.01). Higher levels of IL-17A were detected in serum of patients with lung adenocarcinoma than healthy controls (P < 0.001). Higher positive expressions of IL-17A, IL-17RA and VEGF were confirmed in lung adenocarcinoma lesion tissues compared to pericancerous normal tissues (P < 0.001). Tnc17 cells, as well as Th17 cells were found in adenocarcinoma tissue, indicating a potential role of these cells in disease. In summary, IL-17A might affect lung adenocarcinoma by promoting angiogenesis, while the role of Tnc17 cells or Th17 cells remains to be elucidated.

BM stromal cells ameliorate experimental autoimmune myasthenia gravis by altering the balance of Th cells through the secretion of IDO.

In addition to their capacity to differentiate, BM stromal cells (BMSC) have immunosuppressive qualities that make them strong candidates for use in cell therapy against human autoimmune diseases. We studied the immunoregulatory activities of BMSC on experimental autoimmune myasthenia gravis (EAMG) in vitro and in vivo. Intravenous administration of syngenic BMSC to EAMG-model rats on the day of their second immunization was effective in ameliorating the pathological features of the disease. In vitro, the proliferative ability of T cells or B cells from EAMG rats was inhibited when they were cocultured with BMSC at proper ratios. This inhibitory effect was at least partially dependent on the secretion of IDO. We also determined that the development of EAMG is accompanied by an imbalance among the Th1, Th2, Th17, and Treg cell subsets, and that this can be corrected by the administration of BMSC, which leads to an increase of Th2 (IL-4) and Treg (Foxp3) cells, and a reduction of Th1 (IFN-gamma) and Th17 (IL-17) cells, through an IDO-dependent mechanism. These results provide further insights into the pathogenesis of MG, EAMG, and other immune-mediated diseases, and support a potential role for BMSC in their treatment.

Administration of bone marrow stromal cells ameliorates experimental autoimmune myasthenia gravis by altering the balance of Th1/Th2/Th17/Treg cell subsets through the secretion of TGF-beta.

Bone marrow stromal cells (BMSCs) are strong candidates for cell therapy against human autoimmune diseases. Intravenous administration of syngenic BMSCs to EAMG-model rats effectively ameliorated the disease, partially through a TGF-beta-dependent mechanism. The proliferative ability of T or B cells from EAMG rats was inhibited by BMSCs at proper cocultured ratios. And the imbalance of Th1, Th2, Th17 and Treg cell subsets accompanied with the development of EAMG was corrected by the administration of BMSCs. These results provide further insights into the pathogenesis of MG, EAMG, and other immune-mediated diseases, and support a potential role for BMSCs in their treatment.

RAGE expression is up-regulated in human cerebral ischemia and pMCAO rats.

To determine whether the receptor for advanced glycation endproducts (RAGE) contributes to cerebral ischemia, we evaluated RAGE expression in human cerebral ischemia and a model of permanent middle cerebral artery occlusion (pMCAO) in rats. Biopsy specimens were obtained from 12 patients with unilateral cerebral infarction. For the pMCAO model, the middle cerebral artery (MCA) of Sprague-Dawley (SD) rats was permanently occluded. Immunohistochemistry and Western blotting were used to measure RAGE expression in the ischemic hemisphere relative to the normal hemisphere. PC12 cells subjected to oxygen and glucose deprivation (OGD) were used to evaluate the role of RAGE in cell injury. As expected, cerebral ischemia patients expressed elevated levels of RAGE in the ischemic hemisphere. In 1 and 2 days pMCAO rats, levels of RAGE were higher in the ischemic hemisphere relative to the non-ischemic hemisphere, and expression was primarily located in the penumbra of the ischemic hemisphere. In PC12 cells, levels of RAGE increased after 7h of OGD culture. Notably, blockade of RAGE with a selective RAGE antibody in vitro reduced the cytotoxicity caused by OGD. The present data suggest that RAGE is up-regulated in human cerebral ischemia and pMCAO rats, suggesting a role for RAGE in brain ischemia.

[Study on therapy of experimental autoimmune neuritis by bone marrow stromal cells].

AIM: To investigate the therapeutic effect of bone marrow stromal cells (BMSCs) transplantation on experimental autoimmune neuritis (EAN) and study the possible mechanism. METHODS: EAN model was established by immunizing Lewis rats with P(0)180-199 peptide and complete Freund's adjuvant (CFA). In the therapy group, BMSCs (2x10(6) cells/rat) were marked with fluorochrome PKH26 and injected into the rats' caudal vein 10 d after immunization. The therapeutic effect of BMSC transplantation on EAN rats was investigated by clinical assessment, immunohistochemical staining, and ELISA, respectively. RESULTS: The injected BMSCs could migrate to the demyelinated nerve tissues, and the demyelination and inflammatory infiltration was relieved. The infiltration of CD4(+) and CD8(+) T cells and the sera level of IFN-gamma and TNF-alpha were decreased significantly (P<0.05), whereas IL-4 level in the supernatant of cultured lymphocytes was increased (P<0.05). CONCLUSION: Certain therapeutic effect of BMSC transplantation on EAN was observed. BMSCs could reverse the disbalance of Th1/Th2 cells by regulating the cytokine expression and could inhibit the activation and proliferation of T cells.