Alterations of the Mice Gut Microbiome via Schistosoma japonicum Ova-Induced Granuloma

Identification and comparison of intestinal microbial diversity in patients at different stages of hepatic cystic echinococcosis

There is a significant focus on the role of the host microbiome in different outcomes of human parasitic diseases, including cystic echinococcosis (CE). This study was conducted to identify the intestinal microbiome of patients with CE at different stages of hydatid cyst compared to healthy individuals. Stool samples from CE patients as well as healthy individuals were collected. The samples were divided into three groups representing various stages of hepatic hydatid cyst: active (CE1 and CE2), transitional (CE3), and inactive (CE4 and CE5). One family member from each group was selected to serve as a control. The gut microbiome of patients with different stages of hydatid cysts was investigated using metagenomic next-generation amplicon sequencing of the V3-V4 region of the 16S rRNA gene. In this study, we identified 4862 Operational Taxonomic Units from three stages of hydatid cysts in CE patients and healthy individuals with a combined frequency of 2,955,291. The most abundant genera observed in all the subjects were Blautia, Agathobacter, Faecalibacterium, Bacteroides, Bifidobacterium, and Prevotella. The highest microbial frequency was related to inactive forms of CE, and the lowest frequency was observed in the group with active forms. However, the lowest OTU diversity was found in patients with inactive cysts compared with those with active and transitional cyst stages. The genus Agatobacter had the highest OTU frequency. Pseudomonas, Gemella, and Ligilactobacillus showed significant differences among the patients with different stages of hydatid cysts. Additionally, Anaerostipes and Candidatus showed significantly different reads in CE patients compared to healthy individuals. Our findings indicate that several bacterial genera can play a role in the fate of hydatid cysts in patients at different stages of the disease.

Gut microbiota and immune profiling of microbiota-humanised versus wildtype mouse models of hepatointestinal schistosomiasis

Mounting evidence of the occurrence of direct and indirect interactions between the human blood fluke, Schistosoma mansoni, and the gut microbiota of rodent models raises questions on the potential role(s) of the latter in the pathophysiology of hepatointestinal schistosomiasis. However, substantial differences in both the composition and function between the gut microbiota of laboratory rodents and that of humans hinders an in-depth understanding of the significance of such interactions for human schistosomiasis. Taking advantage of the availability of a human microbiota-associated mouse model (HMA), we have previously highlighted differences in infection-associated changes in gut microbiota composition between HMA and wildtype (WT) mice. To further explore the dynamics of schistosome-microbiota relationships in HMA mice, in this study we (i) characterize qualitative and quantitative changes in gut microbiota composition of a distinct line of HMA mice (D2 HMA) infected with S. mansoni prior to and following the onset of parasite egg production; (ii) profile local and systemic immune responses against the parasite in HMA as well as WT mice and (iii) assess levels of faecal inflammatory markers and occult blood as indirect measures of gut tissue damage. We show that patent S. mansoni infection is associated with reduced bacterial alpha diversity in the gut of D2 HMA mice, alongside expansion of hydrogen sulphide-producing bacteria. Similar systemic humoral responses against S. mansoni in WT and D2 HMA mice, as well as levels of faecal lipocalin and markers of alternatively activated macrophages, suggest that these are independent of baseline gut microbiota composition. Qualitative comparative analyses between faecal microbial profiles of S. mansoni-infected WT and distinct lines of HMA mice reveal that, while infection-induced alterations of the gut microbiota composition are highly dependent on the baseline flora, bile acid composition and metabolism may represent key elements of schistosome-microbiota interactions through the gut-liver axis.

Advances in the study of the interaction between schistosome infections and the host's intestinal microorganisms

Schistosomiasis, also called bilharziasis, is a neglected tropical disease induced by schistosomes that infects hundreds of millions of people worldwide. In the life cycle of schistosomiasis, eggs are regarded as the main pathogenic factor, causing granuloma formation in the tissues and organs of hosts, which can cause severe gastrointestinal and liver granulomatous immune responses and irreversible fibrosis. Increasing evidence suggests that the gut microbiome influences the progression of schistosomiasis and plays a central role in liver disease via the gut-liver axis. When used as pharmaceutical supplements or adjunctive therapy, probiotics have shown promising results in preventing, mitigating, and even treating schistosomiasis. This review elucidates the potential mechanisms of this three-way parasite-host-microbiome interaction by summarizing schistosome-mediated intestinal flora disorders, local immune changes, and host metabolic changes, and elaborates the important role of the gut microbiome in liver disease after schistosome infection through the gut-liver axis. Understanding the mechanisms behind this interaction may aid in the discovery of probiotics as novel therapeutic targets and sustainable control strategies for schistosomiasis.

Neurobiology of Pathogen Avoidance and Mate Choice: Current and Future Directions

Animals are under constant threat of parasitic infection. This has influenced the evolution of social behaviour and has strong implications for sexual selection and mate choice. Animals assess the infection status of conspecifics based on various sensory cues, with odours/chemical signals and the olfactory system playing a particularly important role. The detection of chemical cues and subsequent processing of the infection threat that they pose facilitates the expression of disgust, fear, anxiety, and adaptive avoidance behaviours. In this selective review, drawing primarily from rodent studies, the neurobiological mechanisms underlying the detection and assessment of infection status and their relations to mate choice are briefly considered. Firstly, we offer a brief overview of the aspects of mate choice that are relevant to pathogen avoidance. Then, we specifically focus on the olfactory detection of and responses to conspecific cues of parasitic infection, followed by a brief overview of the neurobiological systems underlying the elicitation of disgust and the expression of avoidance of the pathogen threat. Throughout, we focus on current findings and provide suggestions for future directions and research.

Form and Function in the Digenea, with an Emphasis on Host-Parasite and Parasite-Bacteria Interactions

This review covers the general aspects of the anatomy and physiology of the major body systems in digenetic trematodes, with an emphasis on new knowledge of the area acquired since the publication of the second edition of this book in 2019. In addition to reporting on key recent advances in the morphology and physiology of tegumentary, sensory, neuromuscular, digestive, excretory, and reproductive systems, and their roles in host-parasite interactions, this edition includes a section discussing the known and putative roles of bacteria in digenean biology and physiology. Furthermore, a brief discussion of current trends in the development of novel treatment and control strategies based on a better understanding of the trematode body systems and associated bacteria is provided.

Alterations in gut microbiome and metabolite profile of patients with Schistosoma japonicum infection

BACKGROUND

Schistosoma infection is a significant public health issue, affecting over 200 million individuals and threatening 700 million people worldwide. The species prevalent in China is Schistosoma japonicum. Recent studies showed that both gut microbiota and metabolome are closely related to schistosomiasis caused by S. japonicum, but clinical study is limited and the underlying mechanism is largely unclear. This study aimed to explore alterations as well as function of gut microbiota and metabolite profile in the patients with S. japonicum infection.

METHODS

This study included 20 patients diagnosed with chronic schistosomiasis caused by S. japonicum, eight patients with advanced schistosomiasis caused by S. japonicum and 13 healthy volunteers. The fresh feces of these participators, clinical examination results and basic information were collected. 16S ribosomal RNA gene sequencing was used to investigate gut microbiota, while ultraperformance liquid chromatography-mass spectrometry (UHPLC-MS) was applied to explore the metabolome of patients in different stages of schistosomiasis.

RESULTS

The study found that gut microbiota and metabolites were altered in patients with different stages of S. japonicum infection. Compared with healthy control group, the gut microbial diversity in patients with chronic S. japonicum infection was decreased significantly. However, the diversity of gut microbiota in patients with chronic schistosomiasis was similar to that in patients with advanced schistosomiasis. Compared with uninfected people, patients with schistosomiasis showed decreased Firmicutes and increased Proteobacteria. As disease progressed, Firmicutes was further reduced in patients with advanced S. japonicum infection, while Proteobacteria was further increased. In addition, the most altered metabolites in patients with S. japonicum infection were lipids and lipid-like molecules as well as organo-heterocyclic compounds, correlated with the clinical manifestations and disease progress of schistosomiasis caused by S. japonicum.

CONCLUSIONS

This study suggested that the gut microbiota and metabolome altered in patients in different stages of schistosomiasis, which was correlated with progression of schistosomiasis caused by S. japonicum. This inter-omics analysis may shed light on a better understanding of the mechanisms of the progression of S. japonicum infection and contribute to identifying new potential targets for the diagnosis and prognosis of S. japonicum infection. However, a large sample size of validation in clinic is needed, and further study is required to investigate the underlying mechanism.

Bacillus amyloliquefaciens alleviates the pathological injuries in mice infected with Schistosoma japonicum by modulating intestinal microbiome

Schistosoma japonicum causes serious pathological organ damage and alteration of the intestinal microbiome in the mammalian host, threatening the health of millions of people in China. Bacillus amyloliquefaciens has been reported to be able to alleviate the damage to the gut and liver and maintain the homeostasis of the intestinal microenvironment. However, it was unclear whether B. amyloliquefaciens could alleviate the hepatic and intestinal symptoms caused by S. japonicum. In this study, the intragastric administration of B. amyloliquefaciens was performed to treat S. japonicum-infected mice during the acute phase. Histopathological analysis and 16S rRNA gene sequencing were used to evaluate the pathological damage and changes in the intestinal microbiome. The results of the study showed that B. amyloliquefaciens treatment significantly reduced the degree of granuloma and fibrosis in infected mice. Additionally, recovery of diversity in the intestinal microbiome, decrease in the relative abundance of potential pathogenic bacteria such as Escherichia-Shigella, and reshaping of the interactive network between genera in the intestine were also observed after treatment with B. amyloliquefaciens. Our findings indicated that treatment with B. amyloliquefaciens effectively alleviated the pathological injuries of the liver and intestine in mice infected with S. japonicum by modulating the intestinal microbiome, implying that this probiotic can function as an effective therapeutic agent against schistosomiasis. We hope our study will provide auxiliary strategies and methods for the early prevention of schistosomiasis japonica.

Impact of helminth-microbiome interactions on childhood health and development-A clinical perspective

Humans have co-existed with parasites for virtually the entirety of our existence as a species. Today, nearly one third of the human population is infected with at least one helminthic species, most of which reside in the intestinal tract, where they have co-evolved alongside the human gut microbiota (GM). Appreciation for the interconnected relationship between helminths and GM has increased in recent years. Here, we review the evidence of how helminths and GM can influence various aspects of childhood development and the onset of paediatric diseases. We discuss the emerging evidence of how many of the changes that parasitic worms inflict on their host is enacted through gut microbes. In this light, we argue that helminth-induced microbiota modifications are of great importance in both facing the global challenge of overcoming parasitic infections, and in replicating helminthic protective effects against inflammatory diseases. We propose that deepening our knowledge of helminth-microbiota interactions will uncover novel, safer and more effective therapeutic strategies in combatting an array of childhood disorders.

The role of the host gut microbiome in the pathophysiology of schistosomiasis

The pathophysiology of schistosomiasis is linked to the formation of fibrous granulomas around eggs that become trapped in host tissues, particularly the intestines and liver, during their migration to reach the lumen of the vertebrate gut. While the development of Schistosoma egg-induced granulomas is the result of finely regulated crosstalk between egg-secreted antigens and host immunity, evidence has started to emerge of the likely contribution of an additional player-the host gut microbiota-to pathological processes that culminate with the formation of these tissue lesions. Uncovering the role(s) of schistosome-mediated changes in gut microbiome composition and function in granuloma formation and, more broadly, in the pathophysiology of schistosomiasis, will shed light on the mechanisms underlying this three-way parasite-host-microbiome interplay. Such knowledge may, in turn, pave the way towards the discovery of novel therapeutic targets and control strategies.

Parasite infections, neuroinflammation, and potential contributions of gut microbiota

Many parasitic diseases (including cerebral malaria, human African trypanosomiasis, cerebral toxoplasmosis, neurocysticercosis and neuroschistosomiasis) feature acute or chronic brain inflammation processes, which are often associated with deregulation of glial cell activity and disruption of the brain blood barrier's intactness. The inflammatory responses of astrocytes and microglia during parasite infection are strongly influenced by a variety of environmental factors. Although it has recently been shown that the gut microbiota influences the physiology and immunomodulation of the central nervous system in neurodegenerative diseases like Alzheimer's disease and Parkinson's, the putative link in parasite-induced neuroinflammatory diseases has not been well characterized. Likewise, the central nervous system can influence the gut microbiota. In parasite infections, the gut microbiota is strongly perturbed and might influence the severity of the central nervous system inflammation response through changes in the production of bacterial metabolites. Here, we review the roles of astrocytes and microglial cells in the neuropathophysiological processes induced by parasite infections and their possible regulation by the gut microbiota.

The gut microbial metabolic capacity of microbiome-humanized vs. wild type rodents reveals a likely dual role of intestinal bacteria in hepato-intestinal schistosomiasis

Increasing evidence shows that the host gut microbiota might be involved in the immunological cascade that culminates with the formation of tissue granulomas underlying the pathophysiology of hepato-intestinal schistosomiasis. In this study, we investigated the impact of Schistosoma mansoni infection on the gut microbial composition and functional potential of both wild type and microbiome-humanized mice. In spite of substantial differences in microbiome composition at baseline, selected pathways were consistently affected by parasite infection. The gut microbiomes of infected mice of both lines displayed, amongst other features, enhanced capacity for tryptophan and butyrate production, which might be linked to the activation of mechanisms aimed to prevent excessive injuries caused by migrating parasite eggs. Complementing data from previous studies, our findings suggest that the host gut microbiome might play a dual role in the pathophysiology of schistosomiasis, where intestinal bacteria may contribute to egg-associated pathology while, in turn, protect the host from uncontrolled tissue damage.

Keratinocyte-derived defensins activate neutrophil-specific receptors Mrgpra2a/b to prevent skin dysbiosis and bacterial infection

Healthy skin maintains a diverse microbiome and a potent immune system to fight off infections. Here, we discovered that the epithelial-cell-derived antimicrobial peptides defensins activated orphan G-protein-coupled receptors (GPCRs) Mrgpra2a/b on neutrophils. This signaling axis was required for effective neutrophil-mediated skin immunity and microbiome homeostasis. We generated mutant mouse lines lacking the entire Defensin (Def) gene cluster in keratinocytes or Mrgpra2a/b. Def and Mrgpra2 mutant animals both exhibited skin dysbiosis, with reduced microbial diversity and expansion of Staphylococcus species. Defensins and Mrgpra2 were critical for combating S. aureus infections and the formation of neutrophil abscesses, a hallmark of antibacterial immunity. Activation of Mrgpra2 by defensin triggered neutrophil release of IL-1β and CXCL2 which are vital for proper amplification and propagation of the antibacterial immune response. This study demonstrated the importance of epithelial-neutrophil signaling via the defensin-Mrgpra2 axis in maintaining healthy skin ecology and promoting antibacterial host defense.

A framework for testing the impact of co-infections on host gut microbiomes

Parasitic infections disturb gut microbial communities beyond their natural range of variation, possibly leading to dysbiosis. Yet it remains underappreciated that most infections are accompanied by one or more co-infections and their collective impact is largely unexplored. Here we developed a framework illustrating changes to the host gut microbiome following single infections, and build on it by describing the neutral, synergistic or antagonistic impacts on microbial α- and ß-diversity expected from co-infections. We tested the framework on microbiome data from a non-human primate population co-infected with helminths and Adenovirus, and matched patterns reported in published studies to the introduced framework. In this case study, α-diversity of co-infected Malagasy mouse lemurs (Microcebus griseorufus) did not differ in comparison with that of singly infected or uninfected individuals, even though community composition captured with ß-diversity metrices changed significantly. Explicitly, we record stochastic changes in dispersion, a sign of dysbiosis, following the Anna-Karenina principle rather than deterministic shifts in the microbial gut community. From the literature review and our case study, neutral and synergistic impacts emerged as common outcomes from co-infections, wherein both shifts and dispersion of microbial communities following co-infections were often more severe than after a single infection alone, but microbial α-diversity was not universally altered. Important functions of the microbiome may also suffer from such heavily altered, though no less species-rich microbial community. Lastly, we pose the hypothesis that the reshuffling of host-associated microbial communities due to the impact of various, often coinciding parasitic infections may become a source of novel or zoonotic diseases.

Targeted gut microbiota manipulation attenuates seizures in a model of infantile spasms syndrome

Infantile spasms syndrome (IS) is a devastating early-onset epileptic encephalopathy associated with poor neurodevelopmental outcomes. When first-line treatment options, including adrenocorticotropic hormone and vigabatrin, are ineffective, the ketogenic diet (KD) is often employed to control seizures. Since the therapeutic impact of the KD is influenced by the gut microbiota, we examined whether targeted microbiota manipulation, mimicking changes induced by the KD, would be valuable in mitigating seizures. Employing a rodent model of symptomatic IS, we show that both the KD and antibiotic administration reduce spasm frequency and are associated with improved developmental outcomes. Spasm reductions were accompanied by specific gut microbial alterations, including increases in Streptococcus thermophilus and Lactococcus lactis. Mimicking the fecal microbial alterations in a targeted probiotic, we administered these species in a 5:1 ratio. Targeted probiotic administration reduced seizures and improved locomotor activities in control diet–fed animals, similar to KD-fed animals, while a negative control (Ligilactobacillus salivarius) had no impact. Probiotic administration also increased antioxidant status and decreased proinflammatory cytokines. Results suggest that a targeted probiotic reduces seizure frequency, improves locomotor activity in a rodent model of IS, and provides insights into microbiota manipulation as a potential therapeutic avenue for pediatric epileptic encephalopathies.

Pathogenicity of Salmonella During Schistosoma-Salmonella Co-infections and the Importance of the Gut Microbiota

Antibiotic inefficacy in treating bacterial infections is largely studied in the context of developing resistance mechanisms. However, little attention has been paid to combined diseases mechanisms, interspecies pathogenesis and the resulting impact on antimicrobial treatment. This review will consider the co-infections of Salmonella and Schistosoma mansoni. It summarises the protective mechanisms that the pathophysiology of the two infections confer, which leads to an antibiotic protection phenomenon. This review will elucidate the functional characteristics of the gut microbiota in the context of these co-infections, the pathogenicity of these infections in infected mice, and the efficacy of the antibiotics used in treatment of these co-infections over time. Salmonella-Schistosoma interactions and the mechanism for antibiotic protection are not well established. However, antimicrobial drug inefficacy is an existing phenomenon in these co-infections. The treatment of schistosomiasis to ensure the efficacy of antibiotic therapy for bacterial infections should be considered in co-infected patients.

Potential of human helminth therapy for resolution of inflammatory bowel disease: The future ahead

Inflammatory bowel disease (IBD) is associated with a dysregulated mucosal immune response in the gastrointestinal tract. The number of patients with IBD has increased worldwide, especially in highly industrialized western societies. The population of patients with IBD in North America is forecasted to reach about four million by 2030; meanwhile, there is no definitive therapy for IBD. Current anti-inflammatory, immunosuppressive, or biological treatment may induce and maintain remission, but not all patients respond to these treatments. Recent studies explored parasitic helminths as a novel modality of therapy due to their potent immunoregulatory properties in humans. Research using IBD animal models infected with a helminth or administered helminth-derived products such as excretory-secretory products has been promising, and helminth-microbiota interactions exert their anti-inflammatory effects by modulating the host immunity. Recent studies also indicate that evidence that helminth-derived metabolites may play a role in anticolitic effects. Thus, the helminth shows a potential benefit for treatment against IBD. Here we review the current feasibility of "helminth therapy" from the laboratory for application in IBD management.

Observation of the Gut Microbiota Profile in C57BL/6 Mice Induced by Plasmodium berghei ANKA Infection

The genus of Plasmodium parasites can cause malaria, which is a prevalent infectious disease worldwide, especially in tropical and subtropical regions. C57BL/6 mice infected with P. berghei ANKA (PbA) will suffer from experimental cerebral malaria (ECM). However, the gut microbiota in C57BL/6 mice has rarely been investigated, especially regarding changes in the intestinal environment caused by infectious parasites. P. berghei ANKA-infected (PbA group) and uninfected C57BL/6 (Ctrl group) mice were used in this study. C57BL/6 mice were infected with PbA via intraperitoneal injection of 1 × 10⁶ infected red blood cells. Fecal samples of two groups were collected. The microbiota of feces obtained from both uninfected and infected mice was characterized by targeting the V4 region of the 16S rRNA through the Illumina MiSeq platform. The variations in the total gut microbiota composition were determined based on alpha and beta diversity analyses of 16S rRNA sequencing. The raw sequences from all samples were generated and clustered using ≥ 97% sequence identity into many microbial operational taxonomic units (OTUs). The typical microbiota composition in the gut was dominated by Bacteroidetes, Firmicutes, Proteobacteria, and Verrucomicrobia at the phylum level. Bacteroidetes and Verrucomicrobia were considerably decreased after PbA infection compared with the control group (Ctrl), while Firmicutes and Proteobacteria were increased substantially after PbA infection compared with Ctrl. The alpha diversity index showed that the observed OTU number was increased in the PbA group compared with the Ctrl group. Moreover, the discreteness of the beta diversity revealed that the PbA group samples had a higher number of OTUs than the Ctrl group. LEfSe analysis revealed that several potential bacterial biomarkers were clearly related to the PbA-infected mice at the phylogenetic level. Several bacterial genera, such as Acinetobacter, Lactobacillus, and Lachnospiraceae_NK4A136_group, were overrepresented in the PbA-infected fecal microbiota. Meanwhile, a method similar to gene coexpression network construction was used to generate the OTU co-abundance units. These results indicated that P. berghei ANKA infection could alter the gut microbiota composition of C57BL/6 mice. In addition, potential biomarkers should offer insight into malaria pathogenesis and antimalarial drug and malaria vaccine studies.

Involvement of TLR4 signaling regulated-COX2/PGE2 axis in liver fibrosis induced by Schistosoma japonicum infection

Background

Hepatic stellate cell (HSC) activation plays a pivotal role in hepatic inflammation and liver fibrosis. TLR4 pathway activation has been reported to be involved in mice liver fibrosis induced by hepatitis virus infection, alcohol abuse, biliary ligation, carbon tetrachloride 4 treatment, and Schistosoma japonicum (Sj) infection. The effect and mechanisms of the cyclooxygenase 2 (COX2)/prostanoid E2 (PGE2) axis on liver fibrosis induced by Sj are still unclear.

Methods

Mice liver fibrosis were induced by cutaneous infection of Sj cercariae. COX-2 inhibitor, NS398 were injected from week 5 to week 7, while TLR4 inhibitor TAK242 were injected from week 4 to week 8 post Sj infection. Human HSCs line, LX-2 cells were cultured and exposed to LPS or synthetic PGE2, or pretreated by TAK242, TLR4-siRNA or NS398. Liver tissue and serum or in vitro cultured cell lysaste were collected at indicated time courses for exploring the relationship between TLR4 and COX2-PGE2 axis through qPCR, western blot, immunohistochemical assay, ect. One-way analysis of variance among multiple groups followed by Uncorrected Fisher’s LSD-t test or paired comparisons through t test were performed to tell the statistical differences.

Results

This study investigated the link between the COX2/PGE2 axis and TLR4 signaling in the induction of liver fibrogenesis in mice during Sj infection and in vitro culture of HSC strain-LX-2. The COX2/PGE2 axis was positively associated with Sj-induced liver fibrosis. TLR4 pathway activation stimulated the COX2/PGE2 axis in Sj-infected mice and in lipopolysaccharide (LPS)-exposed cultured HSCs. Synthetic PGE2 activated cultured HSCs through upregulation of alpha smooth muscle actin (α-SMA) expression. In LPS-triggered HSCs, NS398, a COX2 inhibitor, led to suppression of PGE2 synthesis and reduced expression of α-SMA and type I collagen (COL I).

Conclusions

These results indicate firstly the positive association of the COX2/PGE2 axis with liver fibrosis induced by Sj infection. TLR4 signaling may at least partially control the COX2/PGE2 axis in Sj-infected mice liver and in vitro cultured HSCs. The COX2/PGE2-EP2/EP4 axis might be a good drug target against liver fibrosis induced by Sj infection.

Graphic abstract

Gut microbiota signatures in Schistosoma japonicum infection-induced liver cirrhosis patients: a case-control study

Background

Several studies have assessed the role of gut microbiota in various cirrhosis etiologies, however, none has done so in the context of Schistosoma japonicum infection in humans. We, therefore, sought to determine whether gut microbiota is associated with S. japonicum infection-induced liver cirrhosis.

Methods

From December 2017 to November 2019, 24 patients with S. japonicum infection-induced liver cirrhosis, as well as 25 age- and sex-matched controls from the Zhejiang Province, China, were enrolled. Fecal samples were collected and used for 16S rRNA gene sequencing (particularly, the hypervariable V4 region) using the Illumina MiSeq system. Wilcoxon Rank-Sum and PERMANOVA tests were used for analysis.

Results

Eight hundred and seven operational taxonomic units (OTUs) were detected, of which, 491 were common between the two groups, whereas 123 and 193 were unique to the control and cirrhosis groups, respectively. Observed species, Chao, ACE, Shannon, Simpson, and Good’s coverage indexes, used for alpha diversity analysis, showed values of 173.4 ± 63.8, 197.7 ± 73.0, 196.3 ± 68.9, 2.96 ± 0.57, 0.13 ± 0.09, and 1.00 ± 0.00, respectively, in the control group and 154.0 ± 68.1, 178.6 ± 75.1, 179.9 ± 72.4, 2.68 ± 0.76, 0.19 ± 0.18, and 1.00 ± 0.00, respectively, in the cirrhosis group, with no significant differences observed between the groups. Beta diversity was evaluated by weighted UniFrac distances, with values of 0.40 ± 0.13 and 0.40 ± 0.11 in the control and cirrhosis groups, respectively (P > 0.05). PCA data also confirmed this similarity (P > 0.05). Meanwhile, the relative abundance of species belonging to the Bacilli class was higher in cirrhosis patients [median: 2.74%, interquartile range (IQR): 0.18–7.81%] than healthy individuals (median: 0.15%, IQR: 0.47–0.73%; P < 0.01), and that of Lactobacillales order was also higher in cirrhosis patients (median: 2.73%, IQR: 0.16–7.80%) than in healthy individuals (median: 0.12%, IQR: 0.03–0.70%; P < 0.05).

Conclusions

Cumulatively, our results suggest that the gut microbiota of S. japonicum infection-induced liver cirrhosis patients is similar to that of healthy individuals, indicating that bacterial taxa cannot be used as non-invasive biomarkers for S. japonicum infection-induced liver cirrhosis.

Schistosoma japonicum Infection Leads to the Reprogramming of Glucose and Lipid Metabolism in the Colon of Mice

The deposition of Schistosoma japonicum (S. japonicum) eggs commonly induces inflammation, fibrosis, hyperplasia, ulceration, and polyposis in the colon, which poses a serious threat to human health. However, the underlying mechanism is largely neglected. Recently, the disorder of glucose and lipid metabolism was reported to participate in the liver fibrosis induced by the parasite, which provides a novel clue for studying the underlying mechanism of the intestinal pathology of the disease. This study focused on the metabolic reprogramming profiles of glucose and lipid in the colon of mice infected by S. japonicum. We found that S. japonicum infection shortened the colonic length, impaired intestinal integrity, induced egg-granuloma formation, and increased colonic inflammation. The expression of key enzymes involved in the pathways regulating glucose and lipid metabolism was upregulated in the colon of infected mice. Conversely, phosphatase and tensin homolog deleted on chromosome ten (PTEN) and its downstream signaling targets were significantly inhibited after infection. In line with these results, in vitro stimulation with soluble egg antigens (SEA) downregulated the expression of PTEN in CT-26 cells and induced metabolic alterations similar to that observed under in vivo results. Moreover, PTEN over-expression prevented the reprogramming of glucose and lipid metabolism induced by SEA in CT-26 cells. Overall, the present study showed that S. japonicum infection induces the reprogramming of glucose and lipid metabolism in the colon of mice, and PTEN may play a vital role in mediating this metabolic reprogramming. These findings provide a novel insight into the pathogenicity of S. japonicum in hosts.

Alteration of the fecal microbiota in Chinese patients with Schistosoma japonicum infection

Schistosoma japonicum infection causes pathological injury to the host. Multiple studies have shown that intestinal helminth infection causes dysbiosis for the gut microbial community and impacts host immunology. However, the effect of acute S. japonicum infection on the gut microbiome structure (abundance and diversity) is still unclear. We collected fecal samples from healthy and infected patients from a single hospital in Hunan Province, China. The bacterial community was analyzed using 16S ribosomal RNA gene sequencing of the V4 hypervariable region using the HiSeq platform. Compared with healthy subjects, infected patients exhibited an increase in relative abundance of the TM7 phylum. At the genus level, there were seven differentially abundant genera between groups. The most significant finding was a Bacteroides enterotype in patients with acute schistosomiasis. These results suggest that S. japonicum infection has a significant effect on microbiome composition characterized by a higher abundance of the TM7 phylum and development of a Bacteroides enterotype.

Baseline Gut Microbiota Composition Is Associated With Schistosoma mansoni Infection Burden in Rodent Models

In spite of growing evidence supporting the occurrence of complex interactions between Schistosoma and gut bacteria in mice and humans, no data is yet available on whether worm-mediated changes in microbiota composition are dependent on the baseline gut microbial profile of the vertebrate host. In addition, the impact of such changes on the susceptibility to, and pathophysiology of, schistosomiasis remains largely unexplored. In this study, mice colonized with gut microbial populations from a human donor (HMA mice), as well as microbiota-wild type (WT) animals, were infected with Schistosoma mansoni, and alterations of their gut microbial profiles at 50 days post-infection were compared to those occurring in uninfected HMA and WT rodents, respectively. Significantly higher worm and egg burdens, together with increased specific antibody responses to parasite antigens, were observed in HMA compared to WT mice. These differences were associated to extensive dissimilarities between the gut microbial profiles of each HMA and WT groups of mice at baseline; in particular, the gut microbiota of HMA animals was characterized by low microbial alpha diversity and expanded Proteobacteria, as well as by the absence of putative immunomodulatory bacteria (e.g. Lactobacillus). Furthermore, differences in infection-associated changes in gut microbiota composition were observed between HMA and WT mice. Altogether, our findings support the hypothesis that susceptibility to S.mansoni infection in mice is partially dependent on the composition of the host baseline microbiota. Moreover, this study highlights the applicability of HMA mouse models to address key biological questions on host-parasite-microbiota relationships in human helminthiases.

Gut Microbiota Modulates Intestinal Pathological Injury in Schistosoma japonicum-Infected Mice

Trapping of Schistosoma japonicum (S. japonicum) eggs in host tissue, mainly in the intestine and liver, causes severe gastrointestinal and hepatic granulomatous immune responses and irreversible fibrosis. Although the gut microbiota plays a central role in regulating pathological responses in several diseases, the effect of the gut microbiota on the pathologenesis progression of schistosomiasis remains largely unknown. In this study, we aimed to investigate the regulatory function of the gut microbiota in schistosomiasis japonica. We found that the depletion of the gut microbiota significantly ameliorated egg granulomas formation and fibrosis in the intestine of infected mice. This role of the gut microbiota in intestinal granuloma formation and fibrosis was reinforced when normal and infected mice were housed together in one cage. Notably, changes in the gut microbiota induced by S. japonicum infection were partly reversible with microbiota transfer in the cohousing experiment. Transfer of the gut microbiota from normal to infected mice attenuated the intestinal pathological responses. Depletion of the gut microbiota by antibiotics, or transfer of the gut microbiota from normal to infected mice decreased the levels of IL-4, IL-5, and IL-13 and promoted the production of cytokines and mRNA levels of IL-10 and TGF-β in infected mice. Our findings indicated a regulatory effect of the gut microbiota on intestinal pathological injury associated with schistosomiasis japonica in mice, and thus suggested a potential strategy for schistosomiasis treatment.

The microbiota-microglia axis in central nervous system disorders

The innate immune system in the central nervous system (CNS) is mainly represented by specialized tissue-resident macrophages, called microglia. In the past years, various species-, host- and tissue-specific as well as environmental factors were recognized that essentially affect microglial properties and functions in the healthy and diseased brain. Host microbiota are mostly residing in the gut and contribute to microglial activation states, for example, via short-chain fatty acids (SCFAs) or aryl hydrocarbon receptor (AhR) ligands. Thereby, the gut microorganisms are deemed to influence numerous CNS diseases mediated by microglia. In this review, we summarize recent findings of the interaction between the host microbiota and the CNS in health and disease, where we specifically highlight the resident gut microbiota as a crucial environmental factor for microglial function as what we coin "the microbiota-microglia axis."

A longitudinal study reveals the alterations of the Microtus fortis colonic microbiota during the natural resistance to Schistosoma japonicum infection

The gut microbiota has been demonstrated to associate with protection against helminth infection and mediate via microbial effects on the host humoral immunity. As a non-permissive host of Schistosoma japonicum, the Microtus fortis provides an ideal animal model to be investigated, because of its natural self-healing capability. Although researches on the systemic immunological responses have revealed that the host immune system contributes a lot to the resistance, the role of gut microbiome remains unclear. In this study, we exposed the M. fortis to the S.japonicum infection, carried out a longitudinal research (uninfected control, infected for 7 days, 14 days, 21 days, and 31 days) on their colonic microbiota based on the 16S rRNA gene amplicon sequencing. The bacterial composition disclosed a disturbance-recovery alteration followed by the resistance to S. japonicum. The alpha diversity of colon microbiota was reduced after the infection, but it gradually recovered along with self-healing process. Further LEfSe analysis revealed that phyla shifted from Firmicutes to Bacteroidetes, which were mainly driven by an increase of Ruminococcaceae and a depletion of Muribaculaceae in the family level along the Control-Infection-Recovery (CIR) process. We identified a temporary blooming of Lactobacillaceae and Lactobacillus in the mid infection stage (D14). As a recognized probiotics repository, we speculate the increased abundance of Lactobacillaceae in M. fortis colonic microbiota might relate to the natural resistance to the schistosome. Besides, potential microbial functions were also significantly changed in the resistance process. These results demonstrate the remarkable alterations of reed vole colonic microbiota in both community structure and potential functions along with the resistance to S. japonicum infection. The identified microbial biomarkers might offer new ways for drug development to conquer human schistosomiasis.

Alterations of Gut Microbiome and Metabolite Profiling in Mice Infected by Schistosoma japonicum

Schistosoma japonicum (S. japonicum) is one of the etiological agents of schistosomiasis, a widespread zoonotic parasitic disease. However, the mechanism of the balanced co-existence between the host immune system and S. japonicum as well as their complex interaction remains unclear. In this study, 16S rRNA gene sequencing, combined with metagenomic sequencing approach as well as ultraperformance liquid chromatography–mass spectrometry metabolic profiling, was applied to demonstrate changes in the gut microbiome community structure during schistosomiasis progression, the functional interactions between the gut bacteria and S. japonicum infection in BALB/c mice, and the dynamic metabolite changes of the host. The results showed that both gut microbiome and the metabolites were significantly altered at different time points after the infection. Decrease in richness and diversity as well as differed composition of the gut microbiota was observed in the infected status when compared with the uninfected status. At the phylum level, the gut microbial communities in all samples were dominated by Firmicutes, Bacteroidetes, Proteobacteria, and Deferribacteres, while at the genus level, Lactobacillus, Lachnospiraceae NK4A136 group, Bacteroides, Staphylococcus, and Alloprevotella were the most abundant. After exposure, Roseburia, and Ruminococcaceae UCG-014 decreased, while Staphylococcus, Alistipes, and Parabacteroides increased, which could raise the risk of infections. Furthermore, LEfSe demonstrated several bacterial taxa that could discriminate between each time point of S. japonicum infection. Besides that, metagenomic analysis illuminated that the AMP-activated protein kinase (AMPK) signaling pathway and the chemokine signaling pathway were significantly perturbed after the infection. Phosphatidylcholine and colfosceril palmitate in serum as well as xanthurenic acid, naphthalenesulfonic acid, and pimelylcarnitine in urine might be metabolic biomarkers due to their promising diagnostic potential at the early stage of the infection. Alterations of glycerophospholipid and purine metabolism were also discovered in the infection. The present study might provide further understanding of the mechanisms during schistosome infection in aspects of gut microbiome and metabolites, and facilitate the discovery of new targets for early diagnosis and prognostic purposes. Further validations of potential biomarkers in human populations are necessary, and the exploration of interactions among S. japonicum, gut microbiome, and metabolites is to be deepened in the future.

Does Curcumin Have a Role in the Interaction between Gut Microbiota and Schistosoma mansoni in Mice?

There is strong correlation between changes in abundance of specific bacterial species and several diseases including schistosomiasis. Several studies have described therapeutic effects of curcumin (CUR) which may arise from its regulative effects on intestinal microbiota. Thus, we examined the impact of CUR on the diversity of intestinal microbiota with/without infection by Schistosoma mansoni cercariae for 56 days. Enterobacteriaceae was dominating in a naive and S. mansoni infected mice group without CUR treatment, the most predominant species was Escherichia coli with relative density (R.D%) = 80.66% and the least one was Pseudomonas sp. (0.52%). The influence of CUR on murine microbiota composition was examined one week after oral administration of high (40) and low (20 mg/kg b.w.) CUR doses were administered three times, with two day intervals. CUR induced high variation in the Enterobacteriaceae family, characterized by a significant (p < 0.001) reduction in E. coli and asignificant (p < 0.001) increase in Pseudomonas sp. in both naïve and S. mansoni-infected mice, compared to untreated mice, in a dose-dependent manner. Additionally, our study showed the effects of high CUR doses on S. mansoni infection immunological and parasitological parameters. These data support CUR’s ability to promote Pseudomonas sp. known to produce schistosomicidal toxins and offset the sequelae of murine schistosomiasis.

Prior Toxoplasma Gondii Infection Ameliorates Liver Fibrosis Induced by Schistosoma Japonicum through Inhibiting Th2 Response and Improving Balance of Intestinal Flora in Mice

Schistosomiasis is an immunopathogenic disease in which a T helper (Th) cell type 2-like response plays vital roles. Hepatic fibrosis is its main pathologic manifestations, which is the leading cause of hepatic cirrhosis. Co-infections of Schistosoma japonicum (Sj) with other pathogens are frequently encountered but are easily ignored in clinical studies, and effective therapeutic interventions are lacking. In this study, we explored the effect of Toxoplasma gondii (Tg) prior infection on Th1/Th2 response, community shifts in gut microbiome (GM), and the pathogenesis of schistosomiasis in murine hosts. Mice were prior infected with Tg before Sj infection. The effects of co-infection on Th1/Th2 response and hepatic fibrosis were analyzed. Furthermore, we investigated this issue by sequencing 16S rRNA from fecal specimens to define the GM profiles during co-infection. Tg prior infection markedly reduced the granuloma size and collagen deposit in livers against Sj infection. Prior infection promoted a shift toward Th1 immune response instead of Th2. Furthermore, Tg infection promoted the expansion of preponderant flora and Clostridiaceae was identified as a feature marker in the GM of the co-infection group. Redundancy analysis (RDA)/canonical correspondence analysis (CCA) results showed that liver fibrosis, Th1/Th2 cytokines were significantly correlated (P < 0.05) with the GM compositions. Tg infection inhibits hepatic fibrosis by downregulating Th2 immune response against Sj infection, and further promotes the GM shifts through "gut-liver axis" in the murine hosts. Our study may provide insights into potential anti-fibrosis strategies in co-infection individuals.

Neglected Agent Eminent Disease: Linking Human Helminthic Infection, Inflammation, and Malignancy

Helminthic parasitic infection is grossly prevalent across the globe and is considered a significant factor in human cancer occurrence induced by biological agents. Although only three helminths (Schistosoma haematobium, Clonorchis sinensis, and Opisthorchis viverrini) so far have been directly associated with carcinogenesis; there are evidence suggesting the involvement of other species too. Broadly, human helminthiasis can cause chronic inflammation, genetic instability, and host immune modulation by affecting inter- and intracellular communications, disruption of proliferation-anti-proliferation pathways, and stimulation of malignant stem cell progeny. These changes ultimately lead to tumor development through the secretion of soluble factors that interact with host cells. However, the detailed mechanisms by which helminths introduce and promote malignant transformation of host cells are still not clear. Here, we reviewed the current understanding of immune-pathogenesis of helminth parasites, which have been associated with carcinogenesis, and how these infections initiate carcinogenesis in the host.

Impact of Endemic Infections on HIV Susceptibility in Sub-Saharan Africa

Human immunodeficiency virus (HIV) remains a leading cause of global morbidity with the highest burden in Sub-Saharan Africa (SSA). For reasons that are incompletely understood, the likelihood of HIV transmission is several fold higher in SSA than in higher income countries, and most of these infections are acquired by young women. Residents of SSA are also exposed to a variety of endemic infections, such as malaria and various helminthiases that could influence mucosal and systemic immunology. Since these immune parameters are important determinants of HIV acquisition and progression, this review explores the possible effects of endemic infections on HIV susceptibility and summarizes current knowledge of the epidemiology and underlying immunological mechanisms by which endemic infections could impact HIV acquisition. A better understanding of the interaction between endemic infections and HIV may enhance HIV prevention programs in SSA.

Helminth-microbiota cross-talk - A journey through the vertebrate digestive system

The gastrointestinal (GI) tract of vertebrates is inhabited by a vast array of organisms, i.e., the microbiota and macrobiota. The former is composed largely of commensal microorganisms, which play vital roles in host nutrition and maintenance of energy balance, in addition to supporting the development and function of the vertebrate immune system. By contrast, the macrobiota includes parasitic helminths, which are mostly considered detrimental to host health via a range of pathogenic effects that depend on parasite size, location in the GI tract, burden of infection, metabolic activity, and interactions with the host immune system. Sharing the same environment within the vertebrate host, the GI microbiota and parasitic helminths interact with each other, and the results of such interactions may impact, directly or indirectly, on host health and homeostasis. The complex relationships occurring between parasitic helminths and microbiota have long been neglected; however, recent studies point towards a role for these interactions in the overall pathophysiology of helminth disease, as well as in parasite-mediated suppression of inflammation. Whilst several discrepancies in qualitative and quantitative modifications in gut microbiota composition have been described based on host and helminth species under investigation, we argue that attention should be paid to the systems biology of the gut compartment under consideration, as variations in the abundances of the same population of bacteria inhabiting different niches of the GI tract may result in varying functional consequences for host physiology.