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Docosahexaenoeic acid (DHA, 22:6 n-3) is an omega-3 polyunsaturated fatty acid that is found in fish oil and exerts cytotoxic effect on a variety of cell lines. The molecular target, responsible for mediating this effect of DHA, still remains unknown. In this report, we presented experimental evidences for the role of PPAR-gamma in conveying the cytotoxic effect of DHA. We showed that DHA induces apoptosis in Reh and Ramos cells and apoptotic effect of DHA is inhibited by the PPAR-gamma antagonist GW9662, indicating that PPAR-gamma functions as the mediator of the apoptotic effect of DHA. Furthermore, our result showed that DHA induces the PPAR-gamma protein levels in both Reh and Ramos cells. Interestingly, DHA was found to induce the expression of p53 protein in Reh cells in a PPAR-gamma-dependent manner. The up-regulation of p53 protein by DHA kinetically correlated with the activation of caspase 9, caspase 3, and induction of apoptosis, suggesting a role for p53 in DHA-mediated apoptosis in Reh cells. Taken together, these findings suggest a new signaling pathway, DHA-PPAR-gamma-p53, in mediating the apoptotic effect of DHA in Reh cells.

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Peripheral blood fibrocytes make up a newly identified leukocyte subpopulation that displays fibroblast-like properties. These blood-borne cells can rapidly enter the site of injury at the same time as circulating inflammatory cells. Marrow stroma includes a subpopulation of undifferentiated cells that are capable of becoming one of a number of phenotypes, including chondrocytes, osteoblasts, adipocytes, and fibroblasts. Adult human bone marrow contains a minority population of bone marrow mesenchymal stem cells (BMSCs) that contribute to the regeneration of tissues such as bone, cartilage, muscle, ligaments, tendons, fat, and stroma. Evidence that these BMSCs are pluripotent, rather than being a mixture of committed progenitor cells each with a restricted potential, includes their rapid proliferation in culture. We hypothesized that peripheral blood mesenchymal stem cells (PBMSCs) and BMSCs have an effective role in wound healing. In this study, we identified and quantified the marrow stem cells (MSCs) derived from blood and bone marrow recruited and migrated to the wound site. Our results show that the synergistic effects of transforming growth factor-beta (TGF-β) and basic fibroblast growth factor (b-FGF) lead to a significant increase in migration and recruitment of both PBMSCs and BMSCs to the wound site, with more potent effects on PBMSCs as compared with BMSCs. Reverse transcription polymerase chain reaction of collagen type I (COL1A1) transcripts (348 bp) confirmed that TGF-β and b-FGF activate collagen I (production in marrow stem cells at higher transcription levels), with more vigorous effects of TGF-β on PBMSCs as compared with the same condition on BMSCs.

SUMMARYCellular immune mechanisms resulting in interferon-gamma (IFN-g) production are essential for protection against cutaneous leishmaniasis. Antigens of the intracellular amastigote form of the parasite, found in mammalian hosts, are likely to be good candidates for the induction of T cell response and protection from development of leishmaniasis. We purified a stage-specific antigen from amastigote soluble antigen (A-SLA) of Leishmania major by immunoaffinity chromatography. The purified protein was characterized as a cysteine proteinase with enzymatic activity which is inhibited by E-64, and it was named the amastigote cysteine proteinase (ACP). BALB/c mice were immunized by two intraperitoneal injections, at a month interval, of 5 m g of ACP or A-SLA in Freund's complete adjuvant (FCA). Animals were challenged 4 weeks later with 10 6 L. major promastigotes and examined 4 months after the last injection. The immunized animals developed significantly smaller or no lesions compared with controls. Spleen cells from immunized mice showed a significant proliferative response and produced a high level of IFN-g in response to ACP, suggesting the induction of Th1 cells after immunization. These results make 24-kD ACP a possible component for an eventual cocktail vaccine against L. major infection.

Astrocytes actively play a pivotal role in inflammatory disease intensity of central nervous system especially multiple sclerosis (MS). Although IFN-β is a selective therapy for MS but the role of IFN-β in stimulating the astrocytes to produce cytokines is not clearly revealed. Therefore, it is encouraging to assess the modulatory role of IFN-β on astrocytes of brain tissue. The aim of our study was to analyze the molecular mechanisms of recombinant IFN-β 1a directly affecting IL-10, iNOS, MMP-9 and TIMP-1 expression in central nervous system for the first time. In this way, in vitro procedures conducted by human astrocytoma A172 and 1321N1 cell lines as a model system. The total RNA from A172 and 1321N1 cells treated with IFN-β and LPS/IFN-γ/IFN-β and untreated cells were extracted and evaluated for IL-10, iNOS, MMP-9 and TIMP-1 expression by real-time RT-PCR. We found a significant dose-dependent increase in IL-10 gene expression in A172 and 1321N1 cells treated with IFN-β or LPS/IFN-γ/IFN-β. Moreover, a significant decrease was observed in iNOS expression suggesting a similar mechanism of action for both cells. Eventually there were no significant changes concerning the modulation of the MMP-9 and TIMP-1 in response to IFN-β treatment. In part, the immunomodulatory effect of IFN-β may be due to increase of IL-10 and suppression of iNOS expression in astrocytes of brain tissue.

In sum, the current study supports the hypothesis that EA may be used as a promising pre-therapy to prevent the MIH.