ABSTRACT
In previous studies, it was indicated that there is an interaction between neutrophils and mesenchymal stem cells. On the other hand, it seems that the microenvironment of mesenchymal stem cells can affect the status of their related neutrophils. The present study was carried out to investigate the effect of bone marrow-derived mesenchymal stem cell pulsed with 1alpha, 25-dihydroxyvitamin D3 on neutrophils functions. In the present study, at first, after isolation of mesenchymal stem cells from bone marrow of rats, these cells were pulsed with 50,100 and 200 nanomolar of vitamin D3 for 24, 48, and 72h. Then, mesenchymal stem cells co-cultured with neutrophils for 1 hour. Then, they were evaluated for phagocytosis activity against opsonized yeast, respiratory burst by NBT reduction assay, and viability by acridine orange/propidium iodide staining. The data were analyzed using one-way analysis of variance and Dunnett tests. Significance level was considered to be p < 0.05. Phagocytosis ability of neutrophils in all treatments was significant in the minimum concentration of 100 nanomolar. Respiratory intensity of respiratory burst of all the treatments showed significant difference in minimum concentration of 50 nanomolar. Furthermore, vitamin D3 at the minimum concentration of 50 nanomolar caused a significant increase in the mesenchymal stem cells ability for the survival of neutrophils [p < 0.05]. Altogether, it seems that the treatment of bone marrow derived mesenchymal stem cells with vitamin D3 potentiates the function of mesenchymal stem cells in the increase of survival, phagocytic ability and respiratory burst of neutrophil
ABSTRACT
Recent studies have demonstrated an essential role for IL-17 in the pathogenesis of experimental autoimmune encephalomyelitis [EAE]. Furthermore, it has been shown that FoxP3+Treg cells play an important role in the suppression of auto inflammatory reactions. Although, previous studies have determined the immunomodulatory potentials of all-trans-retinoic acid [ATRA], but these immunomodulations have been mostly justified by alteration in Thl/Th2 cytokines. The present study was carried out to investigate the therapeutic effects of ATRA on EAE and its effects on T-helper cells responses. EAE was induced by MOG[35-55] peptide and complete Freund's adjuvant in female C57BL/6 mice. The mice were allocated to two therapeutic groups [n=7 per group]. Treatment with ATRA [500 microg/mouse; every other day] was initiated in treatment group on day 12 when they developed a disability score. EAE controls received vehicle alone with the same schedule. Signs of disease were recorded daily until day 33 when the mice were sacrificed. Splenocytes were tested for proliferation by MTT test, cytokine production by ELISA and FoxP3[+] reg cell frequency by flowcytometry. ATRA significantly reduced the clinical signs of established EAE. Aside from decreasing lymphocytic proliferation [P<0.05], ATRA significantly inhibited the production of pro-inflammatory IL-17 [P<0.005] as well as IFN-gamma [P<0.0005] upon antigen-specific restimulation of splenocytes. FoxP3+Treg cell frequency and IL-10 levels were not altered significantly. However, IFN-gamma to IL-10 and IL-17 to IL-10 ratios decreased significantly [P<0.0005]. Parallel to reducing autoreactive lymphocyte proliferation and cytokine production in favor of pro-inflammatory cytokines, all-trans-retinoic acid ameliorated established experimental autoimmune encephalomyelitis