Thioredoxin peroxidase secreted by Echinococcus granulosus (sensu stricto) promotes the alternative activation of macrophages via PI3K/AKT/mTOR pathway

Effects of annexin B18 from Echinococcus granulosus sensu lato on mouse macrophages

Cystic echinococcosis (CE) is a zoonotic disease, caused by Echinococcus granulosus sensu lato (E. granulosus s. l.), which posed significant public health concern globally. E. granulosus s. l. annexin B18 (EgANXB18) acts as a secretory protein, exerting a crucial influence in mediating host-parasite interactions. Recombinant annexin B18 (rEgANXB18) was expressed by Escherichia coli and the immunoreactivity was assessed by western blotting. The binding affinity between rEgANXB18 and total protein of RAW264.7 cells was assessed by ELISA. The impact of rEgANXB18 on the metabolic activity of RAW264.7 cells was assayed by Cell Counting Kit-8 assay. The mRNA levels of polarization markers (inducible nitrous oxide synthase (iNOS) and arginase 1 (Arg1)) and key cellular factors (IL-1β，IL-6，IL-10 and TNFα) were evaluated by qRT-PCR. rEgANXB18 was successfully expressed and recognized by E. granulosus s.l. infected canine sera, as well as could bind to the total protein of RAW264.7 cells. Additionally, rEgANXB18 could promote metabolic activity at 5, 10, 20, and 40 μg/mL while no significant impact on metabolic activity was observed at 80 μg/mL. Co-culture RAW264.7 cells with rEgANXB18 resulted in significantly upregulation of the transcript levels of polarization markers iNOS and Arg1. Moreover, rEgANXB18 significantly upregulated the transcript levels of IL-1β, IL-6, TNFα, and IL-10, while dose-effect relationship was observed in IL-1β, IL-6, and IL-10. Our results indicated that EgANXB18 showed the potential to regulate immune response of macrophages by shifting the cell polarization and cytokine profile, thereby promoting the parasitism of CE.

Immunomodulatory effects of hydatid antigens on mesenchymal stem cells: gene expression alterations and functional consequences

Background

Cystic echinococcosis, caused by the larval stage of Echinococcus granulosus, remains a global health challenge. Mesenchymal stem cells (MSCs) are renowned for their regenerative and immunomodulatory properties. Given the parasite's mode of establishment, we postulate that MSCs likely play a pivotal role in the interaction between the parasite and the host. This study aims to explore the response of MSCs to antigens derived from Echinococcus granulosus, the etiological agent of hydatid disease, with the hypothesis that exposure to these antigens may alter MSC function and impact the host's immune response to the parasite.

Methods

MSCs were isolated from mouse bone marrow and co-cultured with ESPs, HCF, or pLL antigens. We conducted high-throughput sequencing to examine changes in the MSCs' mRNA expression profile. Additionally, cell cycle, migration, and secretory functions were assessed using various assays, including CCK8, flow cytometry, real-time PCR, Western blot, and ELISA.

Results

Our analysis revealed that hydatid antigens significantly modulate the mRNA expression of genes related to cytokine and chemokine activity, impacting MSC proliferation, migration, and cytokine secretion. Specifically, there was a downregulation of chemokines (MCP-1, CXCL1) and pro-inflammatory cytokines (IL-6, NOS2/NO), alongside an upregulation of anti-inflammatory mediators (COX2/PGE2). Furthermore, all antigens reduced MSC migration, and significant alterations in cellular metabolism-related pathways were observed.

Conclusion

Hydatid disease antigens induce a distinct immunomodulatory response in MSCs, characterized by a shift towards an anti-inflammatory phenotype and reduced cell migration. These changes may contribute to the parasite's ability to evade host defenses and persist within the host, highlighting the complex interplay between MSCs and hydatid disease antigens. This study provides valuable insights into the pathophysiology of hydatid disease and may inform the development of novel therapeutic strategies.

Characterization of the immunosuppressive environment induced by larval Echinococcus granulosus during chronic experimental infection

The larval stage of Echinococcus granulosus causes the chronic infection known as cystic echinococcosis, deploying strong inhibitory mechanisms on host immune responses. Using experimental intraperitoneal infection in C57BL/6 mice, we carried out an in-depth analysis of the local changes in macrophage populations associated with chronic infection. In addition, we analyzed T cells and relevant soluble mediators. Infected animals showed an increase in local cell numbers, mostly accounted for by eosinophils, T cells, and macrophages. Within macrophage populations, the largest increases in cell numbers corresponded to resident large peritoneal macrophages (LPM). Monocyte recruitment appeared to be active, as judged by the increased number of monocytes and cells in the process of differentiation towards LPM, including small (SPM) and converting peritoneal macrophages (CPM). In contrast, we found no evidence of macrophage proliferation. Infection induced the expression of M2 markers in SPM, CPM, and LPM. It also enhanced the expression of the co-inhibitor PD-L1 in LPM, SPM, and CPM and induced the co-inhibitor PD-L2 in SPM and CPM. Therefore, local macrophages acquire M2-like phenotypes with probable suppressive capacities. Regarding T cells, infection induced an increase in the percentage of CD4+ cells that are PD-1+, which represent a potential target of suppression by PD-L1+/PD-L2+ macrophages. In possible agreement, CD4+ T cells from infected animals showed blunted proliferative responses to in vitro stimulation with anti-CD3. Further evidence of immune suppression in the parasite vicinity arose from the observation of an expansion in FoxP3+ CD4+ regulatory T cells and increases in the local concentrations of the anti-inflammatory cytokines TGF-β and IL-1Ra.

Ghrelin regulating liver activity and its potential effects on liver fibrosis and Echinococcosis

Ghrelin widely exists in the central nervous system and peripheral organs, and has biological activities such as maintaining energy homeostasis, regulating lipid metabolism, cell proliferation, immune response, gastrointestinal physiological activities, cognition, memory, circadian rhythm and reward effects. In many benign liver diseases, it may play a hepatoprotective role against steatosis, chronic inflammation, oxidative stress, mitochondrial dysfunction, endoplasmic reticulum stress and apoptosis, and improve liver cell autophagy and immune response to improve disease progression. However, the role of Ghrelin in liver Echinococcosis is currently unclear. This review systematically summarizes the molecular mechanisms by which Ghrelin regulates liver growth metabolism, immune-inflammation, fibrogenesis, proliferation and apoptosis, as well as its protective effects in liver fibrosis diseases, and further proposes the role of Ghrelin in liver Echinococcosis infection. During the infectious process, it may promote the parasitism and survival of parasites on the host by improving the immune-inflammatory microenvironment and fibrosis state, thereby accelerating disease progression. However, there is currently a lack of targeted in vitro and in vivo experimental evidence for this viewpoint.

Hepatic macrophages play critical roles in the establishment and growth of hydatid cysts in the liver during Echinococcus granulosus sensu stricto infection

Cystic echinococcosis (CE) is a worldwide neglected zoonotic disease caused by infection with the larval stage of the tapeworm Echinococcus granulosus sensu lato (E. granulosus s.l.), which predominantly resides in the liver accompanied by mild inflammation. Macrophages constitute the main cellular component of the liver and play a central role in controlling the progression of inflammation and liver fibrosis. However, the role of hepatic macrophages in the establishment and growth of hydatid cysts in the liver during E. granulosus sensu stricto (E. granulosus s.s.) infection has not been fully elucidated. Here, we showed that CD68+ macrophages accumulated in pericystic areas of the liver and that the expression of CD163, a marker of anti-inflammatory macrophages, was more evident in active CE patients than in inactive CE patients. Moreover, in a mouse model of E. granulosus s.s. infection, the pool of hepatic macrophages expanded dramatically through the attraction of massive amounts of monocyte-derived macrophages (MoMFs) to the infection site. These infiltrating macrophages preferentially polarized toward an iNOS+ proinflammatory phenotype at the early stage and then toward a CD206+ anti-inflammatory phenotype at the late stage. Notably, the resident Kupffer cells (KCs) predominantly maintained an anti-inflammatory phenotype to favor persistent E. granulosus s.s. infection. In addition, depletion of hepatic macrophages promoted E. granulosus s.s. larval establishment and growth partially by inhibiting CD4+ T-cell recruitment and liver fibrosis. The above findings demonstrated that hepatic macrophages play a vital role in the progression of CE, contributing to a better understanding of the local inflammatory responses surrounding hydatid cysts and possibly facilitating the design of novel therapeutic approaches for CE.

Long live the host! Proteomic analysis reveals possible strategies for parasitic manipulation of its social host

Parasites with complex life cycles often manipulate the phenotype of their intermediate hosts to increase the probability of transmission to their definitive hosts. Infection with Anomotaenia brevis, a cestode that uses Temnothorax nylanderi ants as intermediate hosts, leads to a multiple-fold extension of host lifespan and to changes in behaviour, morphology and colouration. The mechanisms behind these changes are unknown, as is whether the increased longevity is achieved through parasite manipulation. Here, we demonstrate that the parasite releases proteins into its host with functions that might explain the observed changes. These parasitic proteins make up a substantial portion of the proteome of the hosts' haemolymph, and thioredoxin peroxidase and superoxide dismutase, two antioxidants, exhibited the highest abundances among them. The largest part of the secreted proteins could not be annotated, indicating they are either novel or severely altered during recent coevolution to function in host manipulation. We also detected shifts in the hosts' proteome with infection, in particular an overabundance of vitellogenin-like A in infected ants, a protein that regulates division of labour in Temnothorax ants, which could explain the observed behavioural changes. Our results thus suggest two different strategies that might be employed by this parasite to manipulate its host: secreting proteins with immediate influence on the host's phenotype and altering the host's translational activity. Our findings highlight the intricate molecular interplay required to influence the phenotype of a host and point to potential signalling pathways and genes involved in parasite-host communication.

Molecular characterization and functional implications on mouse peripheral blood mononuclear cells of annexin proteins from Echinococcus granulosus sensu lato

BACKGROUND

Cystic echinococcosis (CE) is a life-threatening zoonotic disease caused by the larval stage of Echinococcus granulosus sensu lato, which employs various strategies to evade the host immune system for survival. Recent advances have revealed the role of annexins as excretory/secretory products, providing new insights into the immune regulation by these proteins in the pathogenesis of CE.

METHODS

Echinococcus granulosus annexin B proteins EgANXB2, EgANXB18, EgANXB20, and EgANXB23 were cloned, expressed, and analyzed using bioinformatic tools. Membrane binding analysis was used to assess their bioactivity, while their immunoreactivity and tissue distribution characteristics were determined experimentally using western blotting and immunofluorescence staining, respectively. Furthermore, quantitative real-time reverse transcription PCR (qRT-PCR) was used to analyze the mRNA expression profiles of EgANXBs in different developmental stages of E. granulosus. Finally, immunofluorescence staining, cell counting kit 8 assays, flow cytometry, transwell migration assays, and qRT-PCR were used to evaluate the functional effects of rEgANXB18 and rEgANXB20 on mouse peripheral blood mononuclear cells (PBMCs).

RESULTS

In this study, we identified four EgANXBs with conserved protein structures and calcium-dependent phospholipid binding activities. rEgANXBs were recognized by serum from sheep infected with E. granulosus and distributed in the germinal layer of fertile cysts. Interestingly, transcription levels of the four EgANXBs were significantly higher in protoscoleces than in 28-day strobilated worms. Moreover, we demonstrated that rEgANXB18 and rEgANXB20 were secretory proteins that could bind to PBMCs and regulate their function. Specifically, rEgANXB18 inhibited cell proliferation and migration while promoting cell apoptosis, NO production, and cytokine profile shifting. In contrast, rEgANXB20 showed limited effects on apoptosis but inhibited NO production.

CONCLUSIONS

Our findings suggested that among the four identified EgANXBs, EgANXB2 and EgANXB23 might play a pivotal role for the development of protoscoleces, while EgANXB18 and EgANXB20, as secretory proteins, appeared to participate in the host-parasite interaction by regulating the function of immune cells.

Echinococcus multilocularis protoscoleces enhance glycolysis to promote M2 Macrophages through PI3K/Akt/mTOR Signaling Pathway

Alveolar Echinococcosis (AE) is a zoonotic parasitic disease caused by Echinococcus multilocularis, but its pathogenesis remains unclear. The primary objective of this study is to explore whether Echinococcus multilocularis protoscoleces (PSCs) regulate macrophage polarization and glucose metabolism by PI3K/Akt/mTOR signaling pathway. We found that large numbers of CD68⁺ macrophages gathered in close liver issue from the lesion in AE patients. PSCs preferentially differentiated into M2 macrophages and the expressions of HK1, PFKL, PKM2, PI3K, Akt, p-Akt, mTOR and p-mTOR increased. The above results show that Echinococcus multilocularis protoscoleces enhance glycolysis to promote M2 macrophages through PI3K/Akt/mTOR signaling pathway.

Evolutionary Adaptations of Parasitic Flatworms to Different Oxygen Tensions

During the evolution of the Earth, the increase in the atmospheric concentration of oxygen gave rise to the development of organisms with aerobic metabolism, which utilized this molecule as the ultimate electron acceptor, whereas other organisms maintained an anaerobic metabolism. Platyhelminthes exhibit both aerobic and anaerobic metabolism depending on the availability of oxygen in their environment and/or due to differential oxygen tensions during certain stages of their life cycle. As these organisms do not have a circulatory system, gas exchange occurs by the passive diffusion through their body wall. Consequently, the flatworms developed several adaptations related to the oxygen gradient that is established between the aerobic tegument and the cellular parenchyma that is mostly anaerobic. Because of the aerobic metabolism, hydrogen peroxide (H₂O₂) is produced in abundance. Catalase usually scavenges H₂O₂ in mammals; however, this enzyme is absent in parasitic platyhelminths. Thus, the architecture of the antioxidant systems is different, depending primarily on the superoxide dismutase, glutathione peroxidase, and peroxiredoxin enzymes represented mainly in the tegument. Here, we discuss the adaptations that parasitic flatworms have developed to be able to transit from the different metabolic conditions to those they are exposed to during their life cycle.

Coding and Noncoding RNA Expression Profiles of Spleen CD4+ T Lymphocytes in Mice with Echinococcosis

Cystic echinococcosis (CE) is a severe and neglected zoonotic disease that poses health and socioeconomic hazards. So far, the prevention and treatment of CE are far from meeting people's ideal expectations. Therefore, to gain insight into the prevention and diagnosis of CE, we explored the changes in RNA molecules and the biological processes and pathways involved in these RNA molecules as E. granulosus infects the host. Interferon (IFN)-γ, interleukin (IL)-2, IL-4, IL-6, IL-10, IL-17A, and tumor necrosis factor (TNF)-α levels in peripheral blood serum of E. granulosus infected and uninfected female BALB/c mice were measured using the cytometric bead array mouse Th1/Th2/Th17 cytokine kit. mRNA, microRNA (miRNA), long noncoding RNA (lncRNA), and circular RNA (circRNA) profiles of spleen CD4+ T cells from the two groups of mice were analyzed using high-throughput sequencing and bioinformatics. The levels of IFN-γ, IL-2, IL-4, IL-6, IL-10, IL-17A, and TNF-α were significantly higher in the serum of the CE mice than in control mice (P < 0.01). In total, 1,758 known mRNAs, 37 miRNAs, 175 lncRNAs, and 22 circRNAs were differentially expressed between infected and uninfected mice (|fold change| ≥ 0.585, P < 0.05). These differentially expressed molecules are involved in chromosome composition, DNA/RNA metabolism, and gene expression in cell composition, biological function, and cell function. Moreover, closely related to the JAK/STAT signaling pathways, mitogen-activated protein kinase signaling pathways, P53 signaling pathways, PI3K/AKT signaling pathways, cell cycle, and metabolic pathways. E. granulosus infection significantly increased the levels of IFN-γ, IL-2, IL-4, IL-6, IL-10, IL-17A, and TNF-α in mouse peripheral blood of mice and significantly changed expression levels of various coding and noncoding RNAs. Further study of these trends and pathways may help clarify the pathogenesis of CE and provide new insights into the prevention and treatment of this disease.

Liquid Biopsy for Promising Non-invasive Diagnostic Biomarkers in Parasitic Infections

BACKGROUND

Liquid biopsy refers to the sampling and molecular analysis of body fluids such as blood, saliva, and urine in contrast to conventional tissue biopsies. Liquid biopsy approach can offer powerful non-invasive biomarkers (circulating markers) for diagnosis and monitoring treatment response of a variety of diseases, including parasitic infections.

METHODS

In this review, we concentrate on cell-free DNA (cfDNA), microRNA (miRNA), and exosomes in the published literature.

RESULTS

Considering the high prevalence and severity of parasitic infections worldwide, circulating biomarkers can provide a new insight into the diagnosis and prognosis of parasites in the near future. Moreover, identifying and characterizing parasite- or host-derived circulating markers are important for a better understanding of the pathogenesis of parasite infection and host-parasite relationship at the molecular level. Profiling of biomarkers for parasitic diseases is a promising potential field, though further studies and optimization strategies are required, both in vitro and in vivo.

CONCLUSION

In this review, we discuss three approaches in the liquid biopsy including circulating cfDNA, miRNAs, and exosomes for diagnosis and evaluation of parasites and summarize circulating biomarkers in non-invasive samples during parasitic infections.

Construction of ceRNA regulatory network in mice with Echinococcosis-induced allergic reactions

BACKGROUND

Cystic echinococcosis (CE) is a common chronic zoonotic parasitic disease infected with the Echinococcus granulosus. This study aimed to construct the competitive endogenous RNA (ceRNA) network and investigate the mechanism of mice in echinococcosis sensitization.

METHODS

The animal model of echinococcosis was established in mice, and the RNA sequencing was then performed using cysts. The differentially expressed RNAs (DERNAs: DEmRNAs, DEmiRNAs, and DElncRNAs) were screened between anaphylactic mice or non-anaphylactic mice and controls, respectively. The interactions of two DERNAs groups were identified and the ceRNA network was constructed. Moreover, the potential biological functions and pathways of the DEmRNAs were explored by enrichment analyses. Finally, the qRT-PCR and the western blot were performed to validate the expression levels of key RNAs and proteins.

RESULTS

A total of 285 common DEmRNAs, 157 common DElncRNAs and 4 common DEmiRNAs were observed. CeRNA network contained 3 DElncRNAs, 4 DEmiRNAs, and 27 DEmRNAs corporately. Enrichment results revealed that the functions of DEmRNAs focus on biological functions and pathways that specifically interact with the immune inflammatory response. In addition, the expression of 1700099I09Rik, let-7a-5p, Ccl28 and IL-13 was validated by RT-qPCR and western blot.

CONCLUSION

In this study, ceRNA network associated with CE sensitization in mice was constructed. The DEmRNAs in this network may be key clues for the immune mechanism of CE sensitization.

Parasite-Derived Excretory-Secretory Products Alleviate Gut Microbiota Dysbiosis and Improve Cognitive Impairment Induced by a High-Fat Diet

High-fat (HF) diet-induced neuroinflammation and cognitive decline in humans and animals have been associated with microbiota dysbiosis via the gut-brain axis. Our previous studies revealed that excretory-secretory products (ESPs) derived from the larval Echinococcus granulosus (E. granulosus) function as immunomodulators to reduce the inflammatory response, while the parasitic infection alleviates metabolic disorders in the host. However, whether ESPs can improve cognitive impairment under obese conditions remain unknown. This study aimed to investigate the effects of E. granulosus-derived ESPs on cognitive function and the microbiota-gut-brain axis in obese mice. We demonstrated that ESPs supplementation prevented HF diet-induced cognitive impairment, which was assessed behaviorally by nest building, object location, novel object recognition, temporal order memory, and Y-maze memory tests. In the hippocampus (HIP) and prefrontal cortex (PFC), ESPs suppressed neuroinflammation and HF diet-induced activation of the microglia and astrocytes. Moreover, ESPs supplementation improved the synaptic ultrastructural impairments and increased both pre- and postsynaptic protein levels in the HIP and PFC compared to the HF diet-treated group. In the colon, ESPs reversed the HF diet-induced gut barrier dysfunction, increased the thickness of colonic mucus, upregulated the expression of zonula occludens-1 (ZO-1), attenuated the translocation of bacterial endotoxins, and decreased the colon inflammation. Notably, ESPs supplementation alleviated the HF diet-induced microbiota dysbiosis. After clarifying the role of antibiotics in obese mice, we found that broad-spectrum antibiotic intervention abrogated the effects of ESPs on improving the gut microbiota dysbiosis and cognitive decline. Overall, the present study revealed for the first time that the parasite-derived ESPs alleviate gut microbiota dysbiosis and improve cognitive impairment induced by a high-fat diet. This finding suggests that parasite-derived molecules may be used to explore novel drug candidates against obesity-associated neurodegenerative diseases.

Modulation of the mTOR pathway plays a central role in dendritic cell functions after Echinococcus granulosus antigen recognition

Immune evasion is a hallmark of persistent echinococcal infection, comprising modulation of innate immune cells and antigen-specific T cell responses. However, recognition of Echinococcus granulosus by dendritic cells (DCs) is a key determinant of the host's response to this parasite. Given that mTOR signaling pathway has been described as a regulator linking metabolism and immune function in DCs, we reported for the first time in these cells, global translation levels, antigen uptake, phenotype, cytokine transcriptional levels, and splenocyte priming activity upon recognition of the hydatid fluid (HF) and the highly glycosylated laminar layer (LL). We found that LL induced a slight up-regulation of CD86 and MHC II in DCs and also stimulated the production of IL-6 and TNF-α. By contrast, HF did not increase the expression of any co-stimulatory molecules, but also down-modulated CD40 and stimulated the expression of the anti-inflammatory cytokine IL-10. Both parasitic antigens promoted protein synthesis through mTOR activation. The use of rapamycin decreased the expression of the cytokines tested, empowered the down-modulation of CD40 and also reduced splenocyte proliferation. Finally, we showed that E. granulosus antigens increase the amounts of LC3-positive structures in DCs which play critical roles in the presentation of these antigens to T cells.

Tropical Medicine in China: Bibliometric Analysis Based on Web of Science (2010-2019)

Purpose

The current study quantitatively assessed research trends in tropical medicine in China via a bibliometric method, which used the Web of Science database to analyse the research-based literature related to tropical medicine published from 2010 to 2019.

Methods

Articles were analysed according to the output and research performance of institutes and countries that collaborated with China. Distribution of keywords was applied to evaluate research trends.

Results

Our findings showed that 3372 articles in the field of tropical medicine have been indexed under the Web of Science database during the past 10 years, indicating that studies pertaining to tropical medicine have been growing from 2010 to 2019. The Chinese Center for Disease Control and Prevention (China CDC) system, which published 549 articles on tropical medicine, may be considered as the flagship of tropical medicine in China. The United States ranked first in internationally collaborative articles with China. Furthermore, Parasite & Vectors, which published 707 papers, emerged as the top journal according to the number of publications.

Conclusions

This study highlights the key institutes and topics pertaining to tropical medicine research in China. Although there has been rapid progress in research on tropical medicine in China, some gaps still remain.

Molecular cloning and functional characterization of a thioredoxin peroxidase gene in Echinococcus multilocularis

Thioredoxin peroxidase (TPx) plays an important role in protecting parasites against oxidative damage. However, studies on the role of TPxs in Echinococcus multilocularis are limited. In this study, one tpx gene of E. multilocularis, named as emtpx-1, was identified. EmTPx-1 shares two positionally conserved cysteine residues (Cys48 and Cys169) with orthologs from other platyhelminths. EmTPx-1 is highly expressed in the germinal layer and present in exosome-like vesicles secreted by E. multilocularis metacestodes. EmTPx-1 displays peroxidase activity, which removes hydrogen peroxide in the presence of dithiothreitol. Furthermore, EmTPx-1 could protect DNA from oxidative damages, and EmTPx-1-expressing E. coli cells had an enhanced resistance to oxidative stress. In addition, EmTPx-1 enhanced the expression of arg1, ym1, and il-10, but suppressed inos, tnf-α, and il-1β expression in LPS-stimulated macrophages. Our data suggest a critical role for EmTPx-1 in oxidative stresses and M2 macrophage polarization.

The host mTOR pathway and parasitic diseases pathogenesis

The mechanistic (or mammalian) target of rapamycin (mTOR) is considered as a critical regulatory enzyme involved in essential signaling pathways affecting cell growth, cell proliferation, protein translation, regulation of cellular metabolism, and cytoskeletal structure. Also, mTOR signaling has crucial roles in cell homeostasis via processes such as autophagy. Autophagy prevents many pathogen infections and is involved on immunosurveillance and pathogenesis. Immune responses and autophagy are therefore key host responses and both are linked by complex mTOR regulatory mechanisms. In recent years, the mTOR pathway has been highlighted in different diseases such as diabetes, cancer, and infectious and parasitic diseases including leishmaniasis, toxoplasmosis, and malaria. The current review underlines the implications of mTOR signals and intricate networks on pathogen infections and the modulation of this master regulator by parasites. Parasitic infections are able to induce dynamic metabolic reprogramming leading to mTOR alterations in spite of many other ways impacting this regulatory network. Accordingly, the identification of parasite effects and interactions over such a complex modulation might reveal novel information regarding the biology of the abovementioned parasites and might allow the development of therapeutic strategies against parasitic diseases. In this sense, the effects of inhibiting the mTOR pathways are also considered in this context in the light of their potential for the prevention and treatment of parasitic diseases.

The Degree of Helicobacter pylori Infection Affects the State of Macrophage Polarization through Crosstalk between ROS and HIF-1α

Methods

The expression of CD86, CD206, and HIF-1α in the gastric mucosa was evaluated through immunohistochemistry. RAW 264.7 cells were cocultured with H. pylori at various multiplicities of infection (MOIs), and iNOS, CD86, Arg-1, CD206, and HIF-1α expression was detected by Western blot, PCR, and ELISA analyses. ROS expression was detected with the fluorescent probe DCFH-DA. Macrophages were also treated with the ROS inhibitor NAC or HIF-1α inhibitor YC-1.

Results

Immunohistochemical staining revealed that the macrophage polarization state was associated with the progression of gastric lesions and state of H. pylori infection. The MOI of H. pylori affected macrophage polarization, and H. pylori enhanced the expression of ROS and HIF-1α in macrophages. A low MOI of H. pylori promoted both the M1 and M2 phenotypes, while a high MOI suppressed the M2 phenotype. Furthermore, ROS inhibition attenuated HIF-1α expression and switched macrophage polarization from M1 to M2. However, HIF-1α inhibition suppressed ROS expression and inhibited both the M1 phenotype and the M2 phenotype. Inhibition of ROS or HIF-1α also suppressed the activation of the Akt/mTOR pathway, which was implicated in H. pylori-induced macrophage polarization.

Conclusions

Macrophage polarization is associated with the progression of gastric lesions and state of H. pylori infection. The MOI of H. pylori influences the macrophage polarization state. Crosstalk between ROS and HIF-1α regulates H. pylori-induced macrophage polarization via the Akt/mTOR pathway.

The Functional Parasitic Worm Secretome: Mapping the Place of Onchocerca volvulus Excretory Secretory Products

Nematodes constitute a very successful phylum, especially in terms of parasitism. Inside their mammalian hosts, parasitic nematodes mainly dwell in the digestive tract (geohelminths) or in the vascular system (filariae). One of their main characteristics is their long sojourn inside the body where they are accessible to the immune system. Several strategies are used by parasites in order to counteract the immune attacks. One of them is the expression of molecules interfering with the function of the immune system. Excretory-secretory products (ESPs) pertain to this category. This is, however, not their only biological function, as they seem also involved in other mechanisms such as pathogenicity or parasitic cycle (molting, for example). We will mainly focus on filariae ESPs with an emphasis on data available regarding Onchocerca volvulus, but we will also refer to a few relevant/illustrative examples related to other worm categories when necessary (geohelminth nematodes, trematodes or cestodes). We first present Onchocerca volvulus, mainly focusing on the aspects of this organism that seem relevant when it comes to ESPs: life cycle, manifestations of the sickness, immunosuppression, diagnosis and treatment. We then elaborate on the function and use of ESPs in these aspects.