Inhibition of COX-2 Ameliorates Murine Liver Schistosomiasis Japonica Through Splenic Cellular Immunoregulation

We have reported the positive association of cyclooxygenase 2 (COX-2)/prostaglandin E2 (PGE2) axis with liver fibrosis induced by Schistosoma japonicum (Sj) infection, and TLR4 signaling controlled this axis. However, how COX-2 regulated immune response during Sj infection is still unclear. Here we further studied the effect of COX-2 specific inhibitor-NS398 on liver granulomatous inflammation, fibrosis and explored the mechanisms via evaluating different immune cell during Sj infection.The results showed that NS398 significantly reduced the size of liver granuloma, spleen and mesenteric lymph node (MLN) and alleviated chronic granulomatous inflammation. Mechanically, it might be via decreasing the numbers of Sj-induced T helper type 1 (Th1), Th2, T follicular helper (Tfh), T follicular regulatory cells (Tfr) and germinal center B (GCB) cells to alleviate the liver inflammation and fibrosis. In addition, there were no difference of the numbers of macrophages, neutrophils, MDSCs,Th17 and total B cells in the spleen of the mice with or without NS-398 treatment. Our above data suggests that COX-2/PGE2 inhibition may represent a potential therapeutic approach to schistosomiasis japonica.

Wnt5A Signaling Blocks Progression of Experimental Visceral Leishmaniasis

Visceral Leishmaniasis, caused by L. donovani infection is fatal if left untreated. The intrinsic complexity of visceral leishmaniasis complicated further by the increasing emergence of drug resistant L. donovani strains warrants fresh investigations into host defense schemes that counter infections. Accordingly, using a mouse model of experimental visceral leishmaniasis we explored the utility of host Wnt5A in restraining L. donovani infection, using both antimony sensitive and antimony resistant L. donovani strains. We found that Wnt5A heterozygous (Wnt5A +/-) mice are more susceptible to L. donovani infection than their wild type (Wnt5A +/+) counterparts as depicted by the respective Leishman Donovan Units (LDU) enumerated from the liver and spleen harvested from infected mice. Higher LDU in Wnt5A +/- mice correlated with increased level of plasma gammaglobulin, liver granuloma and disorganization of splenic germinal centers. Progression of infection in mice by both antimony sensitive and antimony resistant strains of L. donovani could be prevented by activation of Wnt5A signaling as evident from the lowered LDU and gammaglobulin level, and intactness of splenic germinal centers through intravenous administration of rWnt5A prior to L. donovani infection. Wnt5A mediated blockade of L. donovani infection correlated with the preservation of splenic macrophages and activated T cells, and a TH1 like cytokine thrust. Taken together our results indicate that depletion of Wnt5A promotes susceptibility to visceral leishmaniasis and revamping Wnt5A signaling in the host is able to curb L. donovani infection irrespective of antimony sensitivity or resistance and mitigate the progression of visceral leishmaniasis.

In vivo assessment of the antischistosomal activity of curcumin loaded nanoparticles versus praziquantel in the treatment of Schistosoma mansoni

Schistosomiasis is a serious parasitic infection affecting millions worldwide. This study aimed to explore the anti-schistosomal activity of curcumin and curcumin loaded gold-nanoparticles (Cur-GNPs) with or without praziquantel (PZQ). We used six groups of the C57BL/6 mice in which five groups were infected with Schistosoma Mansoni (S. mansoni) cercariae and exhibited, separately, to different treatment regimens of curcumin, curcumin loaded nanoparticle, and PZQ, in addition to one untreated group which acts as a control. Mice were sacrificed at the 8th week where both worms and eggs were counted in the hepatic and porto-mesenteric vessels in the liver and intestine, respectively, in addition to a histopathological examination of the liver granuloma. Curcumin caused a significant reduction in the worms and egg count (45.45%) at the 3rd week. A significant schistosomicidal effect of PZQ was found in all groups. Cur-GNPs combined with PZQ 97.4% reduction of worm burden in the 3rd week and the highest reduction in the intestinal and hepatic egg content, as well, besides 70.1% reduction of the granuloma size. The results suggested the curcumin in combination with PZQ as a strong schistosomicidal regimen against S. mansoni as it alters the hematological, biochemical, and immunological changes induced.