Schistosoma japonicum Infection Promotes the Response of Tfh Cells Through Down-Regulation of Caspase-3-Mediating Apoptosis

Recombinant Interleukin - 2 2 Immunotherapy Ameliorates Inflammation and Promotes the Release of Monoamine Neurotransmitters in the Gut-Brain Axis of Schistosoma mansoni-Infected Mice

Recombinant interleukin-22 (rIL-22) has been reported as a protective agent in murine models of diseases driven by epithelial injury. Parasites have a circadian rhythm and their sensitivity to a certain drug may vary during the day. Therefore, this work aimed to investigate the effect of rIL-22 administration at different times of the day on the inflammation, oxidative status, and neurotransmitter release in the gut-brain axis of the Schistosoma mansoni-infected mice. Sixty male BALB/c mice aged six weeks weighing 25-30 g were divided into a control group (injected intraperitoneally with PBS), mice infected with 80 ± 10 cercariae of S. mansoni (infected group) then injected intraperitoneally with PBS, and rIL-22 treated groups. rIL-22 was administrated intraperitoneally (400 ng/kg) either at the onset or offset of the light phase for 14 days. IL-22 administration reduced the levels of IL-1β, tumor necrosis factor-alpha (TNF-α), nuclear factor kappa beta (NF-κβ), and enhanced the production of IL-22 and IL-17. The treatment with IL-22 increased glutathione (GSH) and reduced malondialdehyde (MDA) and nitric oxide (NO) levels both in the ileum and brain. The B-cell lymphoma 2 (BCL2) protein level in the ileum was diminished after IL-22 administration. Brain-derived neurotrophic factor (BDNF) and neurotransmitter release (serotonin, 5HT, norepinephrine, NE, dopamine, DA, Glutamate, Glu, and -amino butyric acid, GABA) were improved by rIL-22. In conclusion, rIL-22 showed promising immunotherapy for inflammation, oxidative damage, and neuropathological signs associated with schistosomiasis. The efficacy of IL-22 increased significantly upon its administration at the time of light offset.

TLR7 enhancing follicular helper T (Tfh) cells response in C57BL/6 mice infected with Plasmodium yoelii NSM TLR7 mediated Tfh cells in P. yoelii infected mice

Toll-like receptors (TLRs) play an important role in inducing innate and acquired immune responses against infection. However, the effect of Toll-like receptor 7 (TLR7) on follicular helper T (Tfh) cells in mice infected with Plasmodium is still not clear. The results showed that the splenic CD4+ CXCR5+ PD-1+ Tfh cells were accumulated after Plasmodium yoelii NSM infection, the content of splenic Tfh cells was correlated to parasitemia and/or the red blood cells (RBCs) counts in the blood. Moreover, the expression of TLR7 was found higher than TLR2, TLR3 and TLR4 in splenic Tfh cells of the WT mice. TLR7 agonist R848 and the lysate of red blood cells of infected mice (iRBCs) could induce the activation and differentiation of splenic Tfh cells. Knockout of TLR7 leads to a decrease in the proportion of Tfh cells, down-regulated expression of functional molecules CD40L, IFN-γ, IL-21 and IL-10 in Tfh cells; decreased the proportion of plasma cells and antibody production and reduces the expression of STAT3 and Ikzf2 in Tfh cells. Administration of R848 could inhibit parasitemia, enhance splenic Tfh cell activation and increase STAT3 and Ikzf2 expression in Tfh cells. In summary, this study shows that TLR7 could regulate the function of Tfh cells, affecting the immune response in the spleen of Plasmodium yoelii NSM-infected mice.

Plantaricin BM-1 decreases viability of SW480 human colorectal cancer cells by inducing caspase-dependent apoptosis

Plantaricin BM-1 is a class IIa bacteriocin produced by Lactobacillus plantarum BM-1 that has significant antimicrobial activity against food-borne bacteria. In this study, a cell proliferation assay and scanning electron microscopy were used to detect changes in the viability of SW480, Caco-2, and HCT-116 colorectal cancer cells treated with plantaricin BM-1. We found that plantaricin BM-1 significantly reduced the viability of all colorectal cancer cell lines tested, especially that of the SW480 cells. Scanning electron microscopy showed that plantaricin BM-1 treatment reduced the number of microvilli and slightly collapsed the morphology of SW480 cells. Fluorescence microscopy and flow cytometry demonstrated that plantaricin BM-1 induced apoptosis of SW480 cells in a concentration-dependent manner. Western blotting further showed that plantaricin BM-1-induced apoptosis of SW480 cells was mediated by the caspase pathway. Finally, transcriptomic analysis showed that 69 genes were differentially expressed after plantaricin BM-1 treatment (p < 0.05), of which 65 were downregulated and four were upregulated. The Kyoto Encyclopedia of Genes and Genomes enrichment analysis showed that expression levels of genes involved in the TNF, NF-κB, and MAPK signaling pathways, as well as functional categories such as microRNAs in cancer and transcriptional misregulation in cancer, were affected in SW480 cells following the treatment with plantaricin BM-1. In conclusion, plantaricin BM-1 induced death in SW480 cells via the caspase-dependent apoptosis pathway. Our study provides important information for further development of plantaricin BM-1 for potential applications in anti-colorectal cancer.

The Protective Effect of the Soluble Egg Antigen of Schistosoma japonicum in A Mouse Skin Transplantation Model

Background

Organ transplantation is currently an effective method for treating organ failure. Long-term use of immunosuppressive drugs has huge side effects, which severely restricts the long-term survival of patients. Schistosoma can affect the host’s immune system by synthesizing, secreting, or excreting a variety of immunomodulatory molecules, but its role in transplantation was not well defined. In order to explore whether Schistosoma-related products can suppress rejection and induce long-term survival of the transplant, we used soluble egg antigen (SEA) of Schistosoma japonicum in mouse skin transplantation models.

Materials and methods

Each mouse was intraperitoneally injected with 100 μg of SEA three times a week for four consecutive weeks before allogenic skin transplant. Skin transplants were performed on day 0 to observe graft survival. Pathological examination of skin grafts was conducted 7 days post transplantation. The skin grafts were subjected to mRNA sequencing. Bioinformatics analysis was conducted and the expression of hub genes was verified by qPCR. Flow cytometry analysis was performed to evaluate the immune status and validate the results from bioinformatic analysis.

Results

The mean survival time (MST) of mouse skin grafts in the SEA-treated group was 11.67 ± 0.69 days, while that of the control group was 8.00 ± 0.36 days. Pathological analysis showed that Sj SEA treatment led to reduced inflammatory infiltration within skin grafts 7 days after allogenic skin transplantation. Bioinformatics analysis identified 86 DEGs between the Sj SEA treatment group and the control group, including 39 upregulated genes and 47 downregulated genes. Further analysis revealed that Sj SEA mediated regulation on cellular response to interferon-γ, activation of IL-17 signaling and chemokine signaling pathways, as well as cytokine–cytokine receptor interaction. Flow cytometry analysis showed that SEA treatment led to higher percentages of CD4⁺IL-4⁺ T cells and CD4⁺Foxp3⁺ T cells and decreased CD4⁺IFN-γ⁺ T cells in skin transplantation.

Conclusion

Sj SEA treatment suppressed rejection and prolonged skin graft survival by regulating immune responses. Sj SEA treatment might be a potential new therapeutic strategy to facilitate anti-rejection therapy and even to induce tolerance.

Inhibition of COX-2 ameliorates murine liver schistosomiasis japonica through splenic cellular immunoregulation

Background

We have reported the positive association of the 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 regulates immune response during Sj infection is still unclear.

Methods

Hematoxylin and eosin staining was used to evaluate the effect of the COX-2-specific inhibitor NS398 on liver granulomatous inflammation and fibrosis. Flow cytometry was used to explore the frequency and amount of different immune cell infiltration in the spleen during Sj infection.

Results

NS398 significantly reduced the size of liver granuloma, spleen, and mesenteric lymph node (MLN) and alleviated chronic granulomatous inflammation. Mechanically, this might be by decreasing the number of Sj-induced macrophages and T helper type 1 (Th1), Th2, T follicular helper (Tfh), T follicular regulatory (Tfr), and germinal center B (GC B) cells. There were no differences in the number of neutrophils, myeloid-derived suppressor cells, Th17 cells, regulatory T cells (Treg), or total B cells in the spleen of the mice with or without NS398 treatment.

Conclusions

COX-2/PGE2 inhibition may represent a potential therapeutic approach for schistosomiasis japonica through splenic cellular immunoregulation.

Graphical Abstract

TLR7 modulating B-cell immune responses in the spleen of C57BL/6 mice infected with Schistosoma japonicum

B cells played an important role in Schistosoma infection-induced diseases. TLR7 is an intracellular member of the innate immune receptor. The role of TLR7 on B cells mediated immune response is still unclear. Here, C57BL/6 mice were percutaneously infected by S. japonicum for 5-6 weeks. The percentages and numbers of B cells increased in the infected mice (p < 0.05), and many activation and function associated molecules were also changed on B cells. More splenic cells of the infected mice expressed TLR7, and B cells were served as the main cell population. Moreover, a lower level of soluble egg antigen (SEA) specific antibody and less activation associated molecules were found on the surface of splenic B cells from S. japonicum infected TLR7 gene knockout (TLR7 KO) mice compared to infected wild type (WT) mice (p < 0.05). Additionally, SEA showed a little higher ability in inducing the activation of B cells from naive WT mice than TLR7 KO mice (p < 0.05). Finally, the effects of TLR7 on B cells are dependent on the activation of NF-κB p65. Altogether, TLR7 was found modulating the splenic B cell responses in S. japonicum infected C57BL/6 mice.

T follicular helper cells: Their development and importance in the context of helminthiasis

The development of T follicular helper cells (Tfh) is a multifactorial process that occurs in multiple stages. After their activation the Tfh cells interact with the B cells to complete their differentiation. During this process, the Tfh cells begin to express canonical molecules such as the transcription factor B-cell lymphoma 6 protein, the CXC chemokine receptors type 5, and the inducible T-cell costimulator, as well as secreting other molecules such as IL-21. This whole process is regulated positively and negatively by several factors so that the best response is offered in the face of diseases of various origins, among them helminthiasis. In this context, the role of circulating Tfh, IL-4 and IgG subtypes is essential for an effective response against these pathogens. In this review, the migration process and the differentiation of Tfh, the regulation, their cell subtypes and the role of Tfh in the context of helminth infections will be addressed.

Ikzf2 Regulates the Development of ICOS+ Th Cells to Mediate Immune Response in the Spleen of S. japonicum-Infected C57BL/6 Mice

Background

Th cells (helper T cells) have multiple functions in Schistosoma japonicum (S. japonicum) infection. Inducible co-stimulator (ICOS) is induced and expressed in activated T lymphocytes, which enhances the development of B cells and antibody production through the ICOS/ICOSL pathway. It remains unclear about the role and possible regulating mechanism of ICOS+ Th cells in the spleen of S. japonicum-infected C57BL/6 mice.

Methods

C57BL/6 mice were infected with cercariae of S. japonicum through the abdomen. The expression of ICOS, activation markers, and the cytokine production on CD4+ ICOS+ Th cells were detected by flow cytometry (FCM) and quantitative real-time PCR (qRT-PCR). Moreover, the differentially expressed gene data of ICOS+ and ICOS- Th cells from the spleen of infected mice were obtained by mRNA sequencing. Besides, Western blot and chromatin immunoprecipitation (ChIP) were used to explore the role of Ikzf2 on ICOS expression.

Results

After S. japonicum infection, the expression of ICOS molecules gradually increased in splenic lymphocytes, especially in Th cells (P < 0.01). Compared with ICOS- Th cells, more ICOS+ Th cells expressed CD69, CD25, CXCR5, and CD40L (P < 0.05), while less of them expressed CD62L (P < 0.05). Also, ICOS+ Th cells expressed more cytokines, such as IFN-γ, IL-4, IL-10, IL-2, and IL-21 (P < 0.05). RNA sequencing results showed that many transcription factors were increased significantly in ICOS+ Th cells, especially Ikzf2 (P < 0.05). And then, the expression of Ikzf2 was verified to be significantly increased and mainly located in the nuclear of ICOS+ Th cells. Finally, ChIP experiments and dual-luciferase reporter assay confirmed that Ikzf2 could directly bind to the ICOS promoter in Th cells.

Conclusion

In this study, ICOS+ Th cells were found to play an important role in S. japonicum infection to induce immune response in the spleen of C57BL/6 mice. Additionally, Ikzf2 was found to be one important transcription factor that could regulate the expression of ICOS in the spleen of S. japonicum-infected C57BL/6 mice.

MiR-130a-3p Alleviates Liver Fibrosis by Suppressing HSCs Activation and Skewing Macrophage to Ly6Clo Phenotype

Emerging evidences have highlighted the crucial role of microRNAs (miRNAs) in the liver cirrhosis, but the relationship between miR-130a-3p and liver cirrhosis is not entirely clear. As we all know, schistosomiasis, as one of the zoonoses, can lead to liver cirrhosis when it advances. In this study, we investigated the biological functions of miR-130a-3p on the liver fibrosis of schistosomiasis in vivo and in vitro. The mice infected with Schistosoma japonicum (S. japonicum) were treated with lentivirus vector (LV)-miR-130a-3p by hydrodynamic injection through the tail vein. Our findings showed significantly decreased expression of miR-130a-3p both in the serum of patients with cirrhosis and in the liver of mice infected with S. japonicum. The results showed that LV-miR-130a-3p could effectively enter into the liver and alleviate liver granulomatous inflammation and collagen deposition. Simultaneously, LV-miR-130a-3p-promoted macrophages presented the Ly6Clo phenotype, concomitant with the decreased expression of the tissue inhibitor of metalloproteinases (TIMP) 1, and increased the expression of matrix metalloproteinase (MMP) 2, which contributed to the dissolution of collagen. Furthermore, overexpression of miR-130a-3p not only inhibited the activation and proliferation of hepatic stellate cells (HSCs) but also induced the apoptosis of HSCs. In addition, we also confirmed that miR-130a-3p enables to bind with mitogen-activated protein kinase (MAPK) 1 and transforming growth factor-beta receptors (TGFBR) 1 and TGFBR2 genes and inhibit the expressions of these genes. Our findings suggested that miR-130a-3p might represent as the potential candidate biomarker and therapeutic target for the prognosis identification and treatment of schistosomiasis liver fibrosis.

Schistosoma japonicum Infection in Treg-Specific USP21 Knockout Mice

The E3 deubiquitinating enzyme ubiquitin-specific proteolytic enzyme 21 (USP21) plays vital roles in physiological activities and is required for Treg-cell-mediated immune tolerance. Using a murine model infected with Schistosoma japonicum, we observed that there were more cercariae developed into adults and more eggs deposited in the livers of the USP21^fl/flFOXP3^Cre (KO) mice. However, immunohistochemistry showed that the degree of egg granuloma formation and liver fibrosis was reduced. In USP21^fl/flFOXP3^Cre mice, levels of IFN-gamma, IL-4, anti-soluble egg antigen (SEA) IgG and anti-soluble worm antigen preparation (SWAP) IgG increased in blood, as determined using ELISAs and multiplex fluorescent microsphere immunoassays, while the levels of IL-10, lL-17A, IL-23, IL-9, and anti-SEA IgM decreased. In addition, the levels of the USP21 protein and mRNA in the liver and spleen of KO mice decreased. We further observed increased Th1 responses amplified by Tregs (regulatory T cells) and compromised Th17 responses, which alleviated the liver immunopathology. We speculated that these changes were related to polarization of Th1-like Tregs. Our results revealed the roles of USP21 in Treg-cell-mediated regulation of immune interactions between Schistosoma and its host. USP21 may have potential for regulating hepatic fibrosis in patients with schistosomiasis.