Paraquat modulates immunological function in bone marrow-derived macrophages.

The herbicide paraquat (PQ) is known to affect the immune system. Many reports have indicated that PQ impacts on the viability and functions of the immune cells, however, the underlying mechanism in detail is still unknown. The aim of this study was to evaluate the effects of PQ on the free radical production, oxidative stress, cell death and pro-inflammatory gene expression of murine bone marrow-derived macrophages (BMDMs) from C57BL/6NJcl mice in vitro. BMDMs were incubated with PQ at 0, 200 and 400 µM concentrations for 24 h. Intracellular reactive oxygen species (ROS) production, apoptosis, cell viability, nitric oxide, inducible nitric oxide synthase (iNOS), and IL-6 expression levels were measured. The results revealed that PQ treatments led to a decrease in the cell viability and induced apoptotic cell death in a dose-dependent manner. Additionally, PQ also induced the generation of ROS. The mRNA level of the pro-inflammatory mediator genes iNOS and IL-6 were also elevated, while the level of lipid peroxide (malondialdehyde) production remained unaltered. Interestingly, the PQ treatment led to a decrease in the nitric oxide production. These results indicate that the increased cellular ROS production, due to the PQ treatment, induces apoptosis and the herbicide triggers production of iNOS and IL-6 in BMDMs.

The circulating immunoglobulins negatively impact on the parasite clearance in the liver of Leishmania donovani-infected mice via dampening ROS activity.

Visceral leishmaniasis, the most severe form of leishmaniasis, is caused by Leishmania donovani and L. infantum. Immunity to Leishmania infection has been shown to depend on the development of Th1 cells; however, the roles of B cells and antibodies during infection remain unclear. In the present study, we showed that AID and µs double-deficient mice (DKO), which have B cells but not circulating immunoglobulins (cIgs), became resistant to L. donovani infection, whereas µs or AID single-deficient mice did not. This resistance in DKO mice occurred in the liver from an early stage of the infection. The depletion of IFN-γ did not affect the rapid reduction of parasite burden, whereas NADPH oxidases was up-regulated in the livers of infected DKO mice. The inhibition of the reactive oxygen species pathway in vivo by apocynin, a NADPH oxidase inhibitor, resulted in a significant increase in the parasite burden in DKO mice. These results indicate that a circulating Ig deficiency induces a protective response against L. donovani infection by elevating IFN-γ-independent NADPH oxidase activity, and also that cIgs play a regulatory role in controlling L. donovani infection in mice.

Nonencapsulated Trichinella pseudospiralis Infection Impairs Follicular Helper T Cell Differentiation with Subclass-Selective Decreases in Antibody Responses.

Infectious microorganisms often modify host immunity to escape from immune elimination. Trichinella is a unique nematode of the helminth family, whose members parasitize the muscle cells inside the host without robust eliminative reactions. There are several species of Trichinella; some develop in muscle cells that become encapsulated (e.g., Trichinella spiralis) and others in cells that do not encapsulate (e.g., Trichinella pseudospiralis). It has already been established that Trichinella infection affects host immune responses in several experimental immune diseases in animal models; however, most of those studies were done using T. spiralis infection. As host immune responses to T. spiralis and T. pseudospiralis infections have been reported to be different, it is necessary to clarify how T. pseudospiralis infection influences the host immune responses. In this study, we investigated the influence on host humoral immunity in T. pseudospiralis-infected mice. We demonstrated that T. pseudospiralis infection decreased antigen-specific IgG2a and IgG2b antibody (Ab) production in mice immunized with a model antigen. This selective decrease in gamma interferon (IFN-γ)-dependent Ab production was not due to a decrease in IFN-γ production, and we instead found impaired follicular helper T (Tfh) cell differentiation. The affinity maturation of antigen-specific Ab tended to be delayed but was not significant in T. pseudospiralis-infected mice. We also observed that CD11b+ spleen cells in T. pseudospiralis-infected mice expressed CD206 and PD-L2, the phenotype of which was M2 macrophages with weak production of interleukin-6 (IL-6), possibly resulting in impaired Tfh differentiation. Taken together, our results indicate that nonencapsulated Trichinella infection induces selective dampening in humoral immunity with the suppression of Tfh differentiation.

Significance of S100P as a biomarker in diagnosis, prognosis and therapy of opisthorchiasis-associated cholangiocarcinoma.

Cholangiocarcinoma (CCA) is a malignancy of bile duct with the difficulty in early diagnosis, poor prognosis and less alternation in therapy. S100P is a member of S100 family proteins and plays important roles in cancers. We investigated the S100P expression and its correlation with clinicopathology in 78 cases of opisthorchiasis-associated CCA, and the effects of S100P knockdown with shRNA interference on the proliferation, cell cycle, migration, apoptosis and sensitivity to anti-cancer drug. Extremely high expression of S100P mRNA was detected in the CCA tumor tissues. The increased S100P protein expression was immunohistochemically confirmed and localized in the CCA cytoplasm and/or nuclei as well as in the hyperneoplasia and dysplasia bile ducts, but not in normal bile ducts. The intensity of immunostaining was correlated with survival, tumor stage and metastasis, and the high expression could be an independent prognostic factor. High levels of S100P were detected in the serum and bile fluid of CCA patients. The shRNA-mediated knockdown of S100P expression inhibited the proliferation in vitro and in vivo, and migration of CCA cells, arrested cell cycle with the up-regulated expression of cell cycle arrest related factors, p21, p27, GADD45A, and 14-3-3 zeta. S100P knockdown also promoted CCA cell apoptosis by up-regulating expression of apoptosis related factors, DR5, TRADD, caspase 3 and BAX, and increased the sensitivity of CCA cells to the chemotherapeutic agents sunitinib and apigenin. Taken together, this study indicates that S100P might be a promising biomarker for the diagnosis, prognosis and therapy of CCA.

Comparison of lipopolysaccharide-mediated peripheral blood mononuclear cell activation between Brahman and Brahman × Thai native crossbreed cattle.

Background and Aims: Lipopolysaccharide (LPS) is a robust endotoxin known to activate the immune system in cattle. The objective of this study was to investigate the effect of LPS on the morphology, cell viability, malondialdehyde (MDA), nitric oxide (NO), and total antioxidant capacity (TAC) of peripheral blood mononuclear cells (PBMCs) in Brahman and Brahman × Thai native crossbreed cattle. Materials and Methods: PBMCs were isolated from Brahman and Brahman × Thai native crossbreed cattle and treated with 0, 0.1, 1, and 10 µg/mL Escherichia coli LPS, respectively. Morphological changes in PBMCs were assessed at 24 and 48 h. In addition, we measured PBMC cell viability, MDA, NO, and TAC. Results: LPS stimulation caused cell deformation and partial PBMC area enlargement, but there were no differences between Brahman and Brahman × Thai native crossbreed cattle. Stimulation at all levels did not affect the viability of PBMCs (p > 0.05). MDA and NO levels were significantly higher in Brahman cattle than in Brahman Thai native crossbred cattle (p < 0.05). TAC was significantly higher in Brahman × Thai native crossbred cattle than in Brahman cattle (p < 0.05). Conclusion: Immune cells of crossbreed cattle have a higher activation response to LPS than those of purebred cattle, and native crossbreed beef cattle have a higher antioxidant capacity than purebred beef cattle. This result may explain why hybrid cattle of indigenous breeds are more resistant to disease than purebred cattle.

Derrischalcone suppresses cholangiocarcinoma cells through targeting ROS-mediated mitochondrial cell death, Akt/mTOR, and FAK pathways.

Chemotherapy is a palliative treatment for unresectable patients with cholangiocarcinoma (CCA). However, drug resistance is a major cause of the failure of this treatment. Derrischalcone (DC), a novel chalcone isolated from Derris indica fruit, has been shown pharmacologically active; though, the effect of DC on CCA is unknown. The present study investigated the cytotoxic, antiproliferative, anti-migration, and anti-invasion effects and underlying mechanisms of DC on CCA KKU-M156 and KKU-100 cells. Cytotoxicity and apoptosis were evaluated by acridine orange and ethidium bromide fluorescent staining. Reactive oxygen species (ROS) was measured by dihydroethidium assay. Cell proliferation and reproductive cell death were assessed by sulforhodamine B staining and colony-forming assay. Migration and invasion were determined by wound healing and transwell chamber assays. Protein expressions associated with cell death, proliferation, migration, and invasion were analyzed by western immunoblotting. We found that DC induced cytotoxicity and apoptosis in association with ROS formation and oxidative stress. Treatment with N-acetylcysteine suppressed ROS formation and attenuated DC-induced cytotoxic and apoptotic effects. DC increased the expression of p53, p21, Bax, and cytochrome c proteins in association with cell death. DC-induced antiproliferation, colony formation, anti-migration, and anti-invasion were associated with the suppression of Akt/mTOR/cyclin D1 and FAK signaling pathways. These findings suggest that the multi-targeting strategies with DC may be a novel treatment for cancer therapy.