METHODOLOGY: The present study was carried out to determine the role of TLR-4 on eliciting the immunomodulatory effects of recombinant BCG expressing MSP-1C of Plasmodium falciparum leading to the production of NO and IL-10, as well as the expression of iNOS. Six groups of mice (n = 6 per group) were immunised thrice, three weeks apart with intraperitoneal phosphate buffered saline T80 (PBS-T80), BCG or rBCG in the presence or absence of a TLR-4 inhibitor; TAK-242, given one hour prior to each immunisation. Peritoneal macrophages were harvested from the mice and cultured for the determination of NO, iNOS and IL-10 via Griess assay, ELISA and Western blot respectively.
RESULTS: The results showed significant inhibition of the production of NO and IL-10 and the expression of iNOS in all groups of mice in the presence of TAK-242.
CONCLUSIONS: These results presented evidence of the role of TLR-4/rBCG attachment mechanism in modulating the production of NO and IL-10 and the expression of iNOS in response to our rBCG-based malaria vaccine candidate expressing MSP-1C of P. falciparum.
METHODS: In vitro anti-inflammatory activity and hydrogen peroxide (H2O2) scavenging activity were performed according to the established procedure. Inflammation was induced using CARR in BALB/c mice at the foot paw and peritoneal cavity. Hourly measurement of paw swelling was performed. The level of nitric oxide (NO), myeloperoxidase (MPO), cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2) and nuclear factor κB (NF-κB) was determined using enzyme-linked immunosorbent assay (ELISA). Peritoneal fluid was collected to investigate total count, differential count of leukocytes, and capillary permeability.
RESULTS: In vitro anti-inflammatory evaluations revealed the potential role of MAOI to inhibit heat-induced protein denaturation and human red cell membrane destabilization. H2O2 inhibition activity of MAOI also proved their powerful role as an H2O2 scavenger. Treatment with MAOI in CARR-induced mice significantly reduced paw edema, leukocyte extravasation, and total and differential leukocyte count. The result of ELISA showed MAOI effectively reduce the level of COX-2, PGE2 and NF-κB in inflamed tissue.
CONCLUSIONS: In short, this study demonstrates that inhibition of H2O2 by MAOI alleviates CARR-induced paw edema possibly by inhibiting the H2O2-mediated NF-κB-COX-2 pathway. The present investigation identifies MAOI might reprofile for the treatment of acute inflammation also, the MAO enzyme may use as a novel therapeutic target to design and develop new class of anti-inflammatory agents.