Helminth infection promotes colonization resistance via type 2 immunity

Functional characterization of helminth-associated Clostridiales reveals covariates of Treg differentiation

BACKGROUND

Parasitic helminths influence the composition of the gut microbiome. However, the microbiomes of individuals living in helminth-endemic regions are understudied. The Orang Asli, an indigenous population in Malaysia with high burdens of the helminth Trichuris trichiura, display microbiotas enriched in Clostridiales, an order of spore-forming obligate anaerobes with immunogenic properties. We previously isolated novel Clostridiales that were enriched in these individuals and found that a subset promoted the Trichuris life cycle. In this study, we aimed to further characterize the functional properties of these bacteria.

RESULTS

Clostridiales isolates were profiled for their ability to perform 57 enzymatic reactions and produce short-chain fatty acids (SCFAs) and hydrogen sulfide, revealing that these bacteria were capable of a range of activities associated with metabolism and host response. Consistent with this finding, monocolonization of mice with individual isolates identified bacteria that were potent inducers of regulatory T-cell (Treg) differentiation in the colon. Comparisons between variables revealed by these studies identified enzymatic properties correlated with Treg induction and Trichuris egg hatching.

CONCLUSION

We identified Clostridiales species that are sufficient to induce high levels of Tregs. We also identified a set of metabolic activities linked with Treg differentiation and Trichuris egg hatching mediated by these newly isolated bacteria. Altogether, this study provides functional insights into the microbiotas of individuals residing in a helminth-endemic region. Video Abstract.

Dual stressors of infection and warming can destabilize host microbiomes

Climate change is causing extreme heating events and intensifying infectious disease outbreaks. Animals harbour microbial communities, which are vital for their survival and fitness under stressful conditions. Understanding how microbiome structures change in response to infection and warming may be important for forecasting host performance under global change. Here, we evaluated alterations in the microbiomes of several wild Caenorhabditis elegans isolates spanning a range of latitudes, upon warming temperatures and infection by the parasite Leucobacter musarum. Using 16S rRNA sequencing, we found that microbiome diversity decreased, and dispersion increased over time, with the former being more prominent in uninfected adults and the latter aggravated by infection. Infection reduced dominance of specific microbial taxa, and increased microbiome dispersion, indicating destabilizing effects on host microbial communities. Exposing infected hosts to warming did not have an additive destabilizing effect on their microbiomes. Moreover, warming during pre-adult development alleviated the destabilizing effects of infection on host microbiomes. These results revealed an opposing interaction between biotic and abiotic factors on microbiome structure. Lastly, we showed that increased microbiome dispersion might be associated with decreased variability in microbial species interaction strength. Overall, these findings improve our understanding of animal microbiome dynamics amidst concurrent climate change and epidemics. This article is part of the theme issue 'Sculpting the microbiome: how host factors determine and respond to microbial colonization'.

Regulation of host metabolic health by parasitic helminths

Obesity is a worldwide pandemic and major risk factor for the development of metabolic syndrome (MetS) and type 2 diabetes (T2D). T2D requires lifelong medical support to limit complications and is defined by impaired glucose tolerance, insulin resistance (IR), and chronic low-level systemic inflammation initiating from adipose tissue. The current preventative strategies include a healthy diet, controlled physical activity, and medication targeting hyperglycemia, with underexplored underlying inflammation. Studies suggest a protective role for helminth infection in the prevention of T2D. The mechanisms may involve induction of modified type 2 and regulatory immune responses that suppress inflammation and promote insulin sensitivity. In this review, the roles of helminths in counteracting MetS, and prospects for harnessing these protective mechanisms for the development of novel anti-diabetes drugs are discussed.

Ascaris lumbricoides harbors a distinct gut microbiota profile from its human host: Preliminary insights

In indigenous populations where soil-transmitted helminths (STH) infections are endemic, STH parasites (i.e., Ascaris lumbricoides, Trichuris trichiura, hookworms) often co-exist and co-evolve with the gut microbiota of their human hosts. The association between STH infections and the gut microbiota of the colonized human hosts has been established, but few studies explored the gut microbiota of the parasites. This preliminary study aimed to characterize the microbiota of the STH parasite for further understanding the STH parasite-host relationship. The gut microbial genomic DNA from four adult A. lumbricoides worms recovered from a six-year-old indigenous Negrito boy living in an STH-endemic village in Perak, Peninsular Malaysia was extracted and sequenced for the V3-V4 region of the 16S rRNA. The microbiota profiles of these worms were characterized and compared with the gut microbiota of their human host, including the profiles from four STH-positive and three STH-negative individuals from the same tribe and village. The gut microbial structure of A. lumbricoides was found to be differed significantly from their human host. The worms contained lower gut bacterial abundance and diversity than human. This difference was evident in the beta diversity analysis which showed a clear separation between the two sample types. While both Firmicutes (52.3%) and Bacteroidetes (36.6%) are the predominant phyla followed by Proteobacteria (7.2%) in the human gut, the microbiota of Ascaris gut is highly dominated by Firmicutes, constituting 84.2% relative abundance (mainly from the genus Clostridium), followed by Proteobacteria (11.1%), Tenericutes (1.8%) and Bacteroidetes (1.5%). The parasites were also found to alter the microbial structure of the human gut following infection based on the relatively higher bacterial abundance in STH-positive versus STH-negative participants. Further studies with a greater number of Ascaris adults and human hosts are needed to confirm the gut microbiota profiles.

Deciphering the Dual Role of Heligmosomoides polygyrus Antigens in Macrophage Modulation and Breast Cancer Cell Growth

In our study, we explored how parasitic nematodes, specifically Heligmosomoides polygyrus, influence the immune response, focusing on their potential role in tumor growth. The study aimed to understand the mechanisms by which these parasites modify immune cell activation, particularly in macrophages, and how this might create an environment conducive to tumor growth. Our methods involved analyzing the effects of H. polygyrus excretory-secretory antigens on macrophage activation and their subsequent impact on breast cancer cell lines EMT6 and 4T1. We observed that these antigens significantly increased the expression of genes associated with both pro-inflammatory and anti-inflammatory molecules, such as inducible nitric oxide synthase, TNF-α, (Tumor Necrosis Factor) Il-6 (Interleukin), and arginase. Additionally, we observed changes in the expression of macrophage surface receptors like CD11b, F4/80, and TLR4 (Toll-like receptor 4). Our findings indicate that the antigens from H. polygyrus markedly alter macrophage behavior and increase the proliferation of breast cancer cells in a laboratory setting. This study contributes to a deeper understanding of the complex interactions between parasitic infections and cancer development, highlighting the need for further research in this area to develop potential new strategies for cancer treatment.

Moniezia benedeni drives CD3+ T cells residence in the sheep intestinal mucosal effector sites

Introduction

T cells are the core of the cellular immunity and play a key role in the regulation of intestinal immune homeostasis. In order to explore the impact Moniezia benedeni (M. benedeni) infection on distributions of CD3+ T cells in the small intestine of the sheep.

Methods

In this study, sheep pET-28a-CD3 recombinant plasmid were constructed and expressed in BL21 receptor cells, then the rabbit anti-sheep CD3 polyclonal antibody was prepared through recombinant protein inducing. The M. benedeni-infected sheep (infection group, n = 6) and healthy sheep (control group, n = 6) were selected, and the distributions of CD3+ T cells in intestinal laminae propria (LP) and mucous epitheliums were observed and analyzed systematically.

Results

The results showed that the rabbit anti-sheep CD3 polyclonal antibody had good potency and specificity. In the effector area of small intestine, a large number of CD3+ T cells were mainly diffusely distributed in the intestinal LP as well as in the mucous epitheliums, and the densities of intestinal LP from duodenum to jejunum to ileum were 6.01 cells/104 μm2, 7.01 cells/104 μm2 and 6.43 cells/104 μm2, respectively. Their distribution densities in mucous epitheliums were 6.71 cells/104 μm2, 7.93 cells/104 μm2 and 7.21 cells/104 μm2, respectively; in the infected group, the distributions of CD3+ T cells were similar to that of the control group, and the densities in each intestinal segment were all significantly increased (p < 0.05), meanwhile, the total densities of CD3+ T cells in duodenum, jejunum and ileum were increased by 33.43%, 14.50%, and 34.19%. In LP and mucous epitheliums, it was increased by 33.57% and 27.92% in duodenum; by 25.82% and 7.07% in jejunum, and by 27.07% and 19.23% in ileum, respectively.

Discussion

It was suggested that M. benedeni infection did not change the spatial distributions of CD3+ T cells in the small intestine of sheep, but significantly increased their densities, which lays a foundation for further research on the regulatory mechanism of sheep intestinal mucosal immune system against M. benedeni infection.

Galectin from Trichinella spiralis alleviates DSS-induced colitis in mice by regulating the intestinal microbiota

According to numerous reports, Trichinella spiralis (T. spiralis) and its antigens can reduce intestinal inflammation by modulating regulatory immunological responses in the host to maintain immune homeostasis. Galectin has been identified as a protein that is produced by T. spiralis, and its characterization revealed this protein has possible immune regulatory activity. However, whether recombinant T. spiralis galectin (rTs-gal) can cure dextran sulfate sodium (DSS)-induced colitis remains unknown. Here, the ability of rTs-gal to ameliorate experimental colitis in mice with inflammatory bowel disease (IBD) as well as the potential underlying mechanism were investigated. The disease activity index (DAI), colon shortening, inflammatory cell infiltration, and histological damage were used as indicators to monitor clinical symptoms of colitis. The results revealed that the administration of rTs-gal ameliorated these symptoms. According to Western blotting and ELISA results, rTs-gal may suppress the excessive inflammatory response-mediated induction of TLR4, MyD88, and NF-κB expression in the colon. Mice with colitis exhibit disruptions in the gut flora, including an increase in gram-negative bacteria, which in turn can result in increased lipopolysaccharide (LPS) production. However, injection of rTs-gal may inhibit changes in the gut microbiota, for example, by reducing the prevalence of Helicobacter and Bacteroides, which produce LPS. The findings of the present study revealed that rTs-gal may inhibit signalling pathways that involve enteric bacteria-derived LPS, TLR4, and NF-κB in mice with DSS-induced colitis and attenuate DSS-induced colitis in animals by modulating the gut microbiota. These findings shed additional light on the immunological processes underlying the beneficial effects of helminth-derived proteins in medicine.

MICDnet: Multimodal information processing networks for Crohn's disease diagnosis

Crohn's disease (CD) is a chronic inflammatory disease with increasing incidence worldwide and unclear etiology. Its clinical manifestations vary depending on location, extent, and severity of the lesions. In order to diagnose Crohn's disease, medical professionals need to comprehensively analyze patients' multimodal examination data, which includes medical imaging such as colonoscopy, pathological, and text information from clinical records. The processes of multimodal data analysis require collaboration among medical professionals from different departments, which wastes a lot of time and human resources. Therefore, a multimodal medical assisted diagnosis system for Crohn's disease is particularly significant. Existing network frameworks find it hard to effectively capture multimodal patient data for diagnosis, and multimodal data for Crohn's disease is currently lacking. In addition,a combination of data from patients with similar symptoms could serve as an effective reference for disease diagnosis. Thus, we propose a multimodal information diagnosis network (MICDnet) to learn CD feature representations by integrating colonoscopy, pathology images and clinical texts. Specifically, MICDnet first preprocesses each modality data, then uses encoders to extract image and text features separately. After that, multimodal feature fusion is performed. Finally, CD classification and diagnosis are conducted based on the fused features. Under the authorization, we build a dataset of 136 hospitalized inspectors, with colonoscopy images of seven areas, pathology images, and clinical record text for each individual. Training MICDnet on this dataset shows that multimodal diagnosis can improve the diagnostic accuracy of CD, and the diagnostic performance of MICDnet is superior to other models.

Akkermansia muciniphila: a deworming partner independent of type 2 immunity

The gut microbiota has coevolved with the host for hundreds of millions of years, playing a beneficial role in host health. Human parasitic helminths are widespread and pose a pervasive global public health issue. Although Type 2 immunity provides partial resistance to helminth infections, the composition of the gut microbiota can change correspondingly. Therefore, it raises the question of what role the gut microbiota plays during helminth infection. Akkermansia muciniphila has emerged as a notable representative of beneficial microorganisms in the gut microbiota. Recent studies indicate that A. muciniphila is not merely associated with helminth infection but is also causally linked to infection. Here, we provide an overview of the crosstalk between A. muciniphila and enteric helminth infection. Our goal is to enhance our understanding of the interplay among A. muciniphila, helminths, and their hosts while also exploring the potential underlying mechanisms.

Trichinella spiralis -induced immunomodulation signatures on gut microbiota and metabolic pathways in mice

The hygiene hypothesis proposes that decreased exposure to infectious agents in developed countries may contribute to the development of allergic and autoimmune diseases. Trichinella spiralis, a parasitic roundworm, causes trichinellosis, also known as trichinosis, in humans. T. spiralis had many hosts, and almost any mammal could become infected. Adult worms lived in the small intestine, while the larvae lived in muscle cells of the same mammal. T. spiralis was a significant public health threat because it could cause severe illness and even death in humans who eat undercooked or raw meat containing the parasite. The complex interactions between gastrointestinal helminths, gut microbiota, and the host immune system present a challenge for researchers. Two groups of mice were infected with T. spiralis vs uninfected control, and the experiment was conducted over 60 days. The 16S rRNA gene sequences and untargeted LC/MS-based metabolomics of fecal and serum samples, respectively, from different stages of development of the Trichinella spiralis-mouse model, were examined in this study. Gut microbiota alterations and metabolic activity accompanied by parasite-induced immunomodulation were detected. The inflammation parameters of the duodenum (villus/crypt ratio, goblet cell number and size, and histological score) were involved in active inflammation and oxidative metabolite profiles. These profiles included increased biosynthesis of phenylalanine, tyrosine, and tryptophan while decreasing cholesterol metabolism and primary and secondary bile acid biosynthesis. These disrupted metabolisms adapted to infection stress during the enteral and parenteral phases and then return to homeostasis during the encapsulated phase. There was a shift from an abundance of Bacteroides in the parenteral phase to an abundance of probiotic Lactobacillus and Treg-associated-Clostridia in the encapsulated phase. Th2 immune response (IL-4/IL-5/IL-13), lamina propria Treg, and immune hyporesponsiveness metabolic pathways (decreased tropane, piperidine and pyridine alkaloid biosynthesis and biosynthesis of alkaloids derived from ornithine, lysine, and nicotinic acid) were all altered. These findings enhanced our understanding of gut microbiota and metabolic profiles of Trichinella -infected mice, which could be a driving force in parasite-shaping immune system maintenance.

Microbial underdogs: exploring the significance of low-abundance commensals in host-microbe interactions

Our understanding of host-microbe interactions has broadened through numerous studies over the past decades. However, most investigations primarily focus on the dominant members within ecosystems while neglecting low-abundance microorganisms. Moreover, laboratory animals usually do not have microorganisms beyond bacteria. The phenotypes observed in laboratory animals, including the immune system, have displayed notable discrepancies when compared to real-world observations due to the diverse microbial community in natural environments. Interestingly, recent studies have unveiled the beneficial roles played by low-abundance microorganisms. Despite their rarity, these keystone taxa play a pivotal role in shaping the microbial composition and fulfilling specific functions in the host. Consequently, understanding low-abundance microorganisms has become imperative to unravel true commensalism. In this review, we provide a comprehensive overview of important findings on how low-abundance commensal microorganisms, including low-abundance bacteria, fungi, archaea, and protozoa, interact with the host and contribute to host phenotypes, with emphasis on the immune system. Indeed, low-abundance microorganisms play vital roles in the development of the host's immune system, influence disease status, and play a key role in shaping microbial communities in specific niches. Understanding the roles of low-abundance microbes is important and will lead to a better understanding of the true host-microbe relationships.

Impact of pinworm infection on the development of murine B-cell leukemia/lymphoma in the presence and absence of ETV6::RUNX1

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Helminths' therapeutic potential to treat intestinal barrier dysfunction

The intestinal barrier is a dynamic multi-layered structure which can adapt to environmental changes within the intestinal lumen. It has the complex task of allowing nutrient absorption while limiting entry of harmful microbes and microbial antigens present in the intestinal lumen. Excessive entry of microbial antigens via microbial translocation due to 'intestinal barrier dysfunction' is hypothesised to contribute to the increasing incidence of allergic, autoimmune and metabolic diseases, a concept referred to as the 'epithelial barrier theory'. Helminths reside in the intestinal tract are in intimate contact with the mucosal surfaces and induce a range of local immunological changes which affect the layers of the intestinal barrier. Helminths are proposed to prevent, or even treat, many of the diseases implicated in the epithelial barrier theory. This review will focus on the effect of helminths on intestinal barrier function and explore whether this could explain the proposed health benefits delivered by helminths.

Excretory-secretory products from adult helminth Nippostrongylus brasiliensis have in vitro bactericidal activity

Introduction. Intestinal helminths and microbiota share the same anatomical niche during infection and are likely to interact either directly or indirectly. Whether intestinal helminths employ bactericidal strategies that influence their microbial environment is not completely understood.Hypothesis. In the present study, the hypothesis that the adult hookworm Nippostrongylus brasiliensis produces molecules that impair bacterial growth in vitro, is tested.Aim. To investigate the in vitro bactericidal activity of Nippostrongylus brasiliensis against commensal and pathogenic bacteria.Methodology. The bactericidal effect of somatic extract and excretory-secretory products of adult Nippostrongylus brasiliensis on Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli, Salmonella enterica serovar Typhimurium, and Klebsiella pneumoniae) bacteria was assessed using growth assays. Minimum inhibitory concentration and minimum bactericidal concentration assays were performed using excretory-secretory products released from the pathogen.Results. Broad-spectrum in vitro bactericidal activity in excretory-secretory products, but not somatic extract of adult Nippostrongylus brasiliensis was detected. The bactericidal activity of excretory-secretory products was concentration-dependent, maintained after heat treatment, and preserved after repeated freezing and thawing.Conclusion. The results of this study demonstrate that helminths such as Nippostrongylus brasiliensis release molecules via their excretory-secretory pathway that have broad-spectrum bactericidal activity. The mechanisms responsible for this bactericidal activity remain to be determined and further studies aimed at isolating and identifying active bactericidal molecules are needed.

Akkermansia muciniphila participates in the host protection against helminth-induced cardiac fibrosis via TLR2

Helminth Trichinella spiralis (Ts) is one of the major pathogens of human infective myocarditis that can lead to cardiac fibrosis (CF). The gut microbiota involved in this pathology are of interest. Here, we use mice infected with Ts as a model to examine the interactions between gut microbes and host protection to CF. Infected mice show enhanced CF severity. We find that antibiotics treatment to deplete the microbiota aggravates the disease phenotype. Attempts to restore microbiota using fecal microbiota transplantation ameliorates helminth-induced CF. 16S rRNA gene sequencing and metagenomics sequencing reveal a higher abundance of Akkermansia muciniphila in gut microbiomes of Ts-infected mice. Oral supplementation with alive or pasteurized A. muciniphila improves CF via TLR2. This work represents a substantial advance toward our understanding of causative rather than correlative relationships between the gut microbiota and CF.

The impact of MIF deficiency on alterations of fecal microbiota in C57BL/6 mice induced by Trichinella spiralis infection

Trichinellosis caused by Trichinella spiralis (T. spiralis) is a major food-borne parasitic zoonosis worldwide. Prevention of trichinellosis is an effective strategy to improve patient quality of life. Macrophage migration inhibitory factor (MIF) is closely related to the occurrence and development of several parasitic diseases. Studying the impact of MIF deficiency (Mif-/- ) on the alterations in host fecal microbiota due to T. spiralis infection may contribute to proposing a novel dual therapeutic approach for trichinellosis. To reveal the diversity and differences in fecal microbial composition, feces were collected from T. spiralis-uninfected and T. spiralis-infected wild-type (WT) and MIF knockout (KO) C57BL/6 mice at 0, 7, 14, and 35 days post-infection (dpi), and the samples were sent for 16S rRNA amplicon sequencing on the Illumina NovaSeq platform. Flow cytometry was used to determine the expression levels of IFN-γ and IL-4 in the CD4+ /CD8+  T-cell sets of mouse spleens. The results showed that operational taxonomic unit (OTU) clustering, relative abundance of microbial composition, alpha diversity, and beta diversity exhibited significant changes among the eight groups. The LEfSe analysis selected several potential biomarkers at the genus or species level, including Akkermansia muciniphila, Lactobacillus murinus, Coprococcus catus, Firmicutes bacterium M10_2, Parabacteroides sp. CT06, and Bacteroides between the KTs and WTs groups. The predicted bacterial functions of the fecal microbiota were mainly involved in metabolism, such as the metabolism of carbohydrates, amino acids, energy, cofactors, vitamins, nucleotides, glycans, and lipids. Flow cytometry revealed an increased CD3+ CD8- /CD3+ CD8+  T-cell ratio and increased IFN-γ and IL-4 levels in CD3+ CD8- T-cell sets from WT and MIF KO mice at 7 dpi. The results indicated that both MIF KO and infection time have a significant influence on the CD3+ CD8- IFN-γ+ and CD3+ CD8- IL-4+ response in mice after T. spiralis. In conclusion, this research showed alterations of the fecal microbiota and immune response in both WT and MIF KO mice before and after T. spiralis infection. These results revealed a potential role of MIF in regulating the pathogenesis of trichinellosis related to the intestinal microbiota. Importantly, the selected potential biomarkers combined with MIF will also offer a novel therapeutic approach to treat trichinellosis in the future.

Bacterial contact induces polar plug disintegration to mediate whipworm egg hatching

The bacterial microbiota promotes the life cycle of the intestine-dwelling whipworm Trichuris by mediating hatching of parasite eggs ingested by the mammalian host. Despite the enormous disease burden associated with Trichuris colonization, the mechanisms underlying this transkingdom interaction have been obscure. Here, we used a multiscale microscopy approach to define the structural events associated with bacteria-mediated hatching of eggs for the murine model parasite Trichuris muris. Through the combination of scanning electron microscopy (SEM) and serial block face SEM (SBFSEM), we visualized the outer surface morphology of the shell and generated 3D structures of the egg and larva during the hatching process. These images revealed that exposure to hatching-inducing bacteria catalyzed asymmetric degradation of the polar plugs prior to exit by the larva. Unrelated bacteria induced similar loss of electron density and dissolution of the structural integrity of the plugs. Egg hatching was most efficient when high densities of bacteria were bound to the poles. Consistent with the ability of taxonomically distant bacteria to induce hatching, additional results suggest chitinase released from larva within the eggs degrade the plugs from the inside instead of enzymes produced by bacteria in the external environment. These findings define at ultrastructure resolution the evolutionary adaptation of a parasite for the microbe-rich environment of the mammalian gut.

Intestinal Helminth Infection Impairs Oral and Parenteral Vaccine Efficacy

The impact of endemic parasitic infection on vaccine efficacy is an important consideration for vaccine development and deployment. We have examined whether intestinal infection with the natural murine helminth Heligmosomoides polygyrus bakeri alters Ag-specific Ab and cellular immune responses to oral and parenteral vaccination in mice. Oral vaccination of mice with a clinically relevant, live, attenuated, recombinant Salmonella vaccine expressing chicken egg OVA (Salmonella-OVA) induced the accumulation of activated, OVA-specific T effector cells rather than OVA-specific regulatory T cells in the GALT. Intestinal helminth infection significantly reduced Th1-skewed Ab responses to oral vaccination with Salmonella-OVA. Activated, adoptively transferred, OVA-specific CD4+ T cells accumulated in draining mesenteric lymph nodes of vaccinated mice, regardless of their helminth infection status. However, helminth infection increased the frequencies of adoptively transferred OVA-specific CD4+ T cells producing IL-4 and IL-10 in the mesenteric lymph node. Ab responses to the oral Salmonella-OVA vaccine were reduced in helminth-free mice adoptively transferred with OVA-specific CD4+ T cells harvested from mice with intestinal helminth infection. Intestinal helminth infection also significantly reduced Th2-skewed Ab responses to parenteral vaccination with OVA adsorbed to alum. These findings suggest that vaccine-specific CD4+ T cells induced in the context of helminth infection retain durable immunomodulatory properties and may promote blunted Ab responses to vaccination. They also underscore the potential need to treat parasitic infection before mass vaccination campaigns in helminth-endemic areas.

Updated immunomodulatory roles of gut flora and microRNAs in inflammatory bowel diseases

Inflammatory bowel disease is a heterogeneous intestinal inflammatory disorder, including ulcerative colitis (UC) and Crohn's disease (CD). Existing studies have shown that the pathogenesis of IBD is closely related to the host's genetic susceptibility, intestinal flora disturbance and mucosal immune abnormalities, etc. It is generally believed that there are complicated interactions between host immunity and intestinal microflora/microRNAs during the occurrence and progression of IBD. Intestinal flora is mainly composed of bacteria, fungi, viruses and helminths. These commensals are highly implicated in the maintenance of intestinal microenvironment homeostasis alone or in combination. MiRNA is an endogenous non-coding small RNA with a length of 20 to 22 nucleotides, which can perform a variety of biological functions by silencing or activating target genes through complementary pairing bonds. A large quantity of miRNAs are involved in intestinal inflammation, mucosal barrier integrity, autophagy, vesicle transportation and other small RNA alterations in IBD circumstance. In this review, the immunomodulatory roles of gut flora and microRNAs are updated in the occurrence and progression of IBD. Meanwhile, the gut flora and microRNA targeted therapeutic strategies as well as other immunomodulatory approaches including TNF-α monoclonal antibodies are also emphasized in the treatment of IBD.

The eukaryome of African children is influenced by geographic location, gut biogeography, and nutritional status

Eukaryotes have historically been studied as parasites, but recent evidence suggests they may be indicators of a healthy gut ecosystem. Here, we describe the eukaryome along the gastrointestinal tract of children aged 2-5 years and test for associations with clinical factors such as anaemia, intestinal inflammation, chronic undernutrition, and age. Children were enrolled from December 2016 to May 2018 in Bangui, Central African Republic and Antananarivo, Madagascar. We analyzed a total of 1104 samples representing 212 gastric, 187 duodenal, and 705 fecal samples using a metabarcoding approach targeting the full ITS2 region for fungi, and the V4 hypervariable region of the 18S rRNA gene for the overall eukaryome. Roughly, half of all fecal samples showed microeukaryotic reads. We find high intersubject variability, only a handful of taxa that are likely residents of the gastrointestinal tract, and frequent co-occurrence of eukaryotes within an individual. We also find that the eukaryome differs between the stomach, duodenum, and feces and is strongly influenced by country of origin. Our data show trends towards higher levels of Fusarium equiseti, a mycotoxin producing fungus, and lower levels of the protist Blastocystis in stunted children compared to nonstunted controls. Overall, the eukaryome is poorly correlated with clinical variables. Our study is of one of the largest cohorts analyzing the human intestinal eukaryome to date and the first to compare the eukaryome across different compartments of the gastrointestinal tract. Our results highlight the importance of studying populations across the world to uncover common features of the eukaryome in health.

Interaction between tissue-dwelling helminth and the gut microbiota drives mucosal immunoregulation

Tissue-dwelling helminths affect billions of people around the world. They are potent manipulators of the host immune system, prominently by promoting regulatory T cells (Tregs) and are generally associated with a modified host gut microbiome. However, the role of the gut microbiota in the immunomodulatory processes for these non-intestinal parasites is still unclear. In the present study, we used an extra-intestinal cestode helminth model-larval Echinococcus multilocularis to explore the tripartite partnership (host-helminth-bacteria) in the context of regulating colonic Tregs in Balb/c mice. We showed that larval E. multilocularis infection in the peritoneal cavity attenuated colitis in Balb/c mice and induced a significant expansion of colonic Foxp3⁺ Treg populations. Fecal microbiota depletion and transplantation experiments showed that the gut microbiota contributed to increasing Tregs after the helminth infection. Shotgun metagenomic and metabolic analyses revealed that the gut microbiome structure after infection was significantly shifted with a remarkable increase of Lactobacillus reuteri and that the microbial metabolic capability was reprogrammed to produce more Treg cell regulator-short-chain fatty acids in feces. Furthermore, we also prove that the L. reuteri strain elevated in infected mice was sufficient to promote the colonic Treg frequency and its growth was potentially associated with T cell-dependent immunity in larval E. multilocularis infection. Collectively, these findings indicate that the extraintestinal helminth drives expansions of host colonic Tregs through the gut microbes. This study suggests that the gut microbiome serves as a critical component of anti-inflammation effects even for a therapy based on an extraintestinal helminth.

Functional characterization of helminth-associated Clostridiales reveals covariates of Treg differentiation

Parasitic helminths influence the composition of the gut microbiome. However, the microbiomes of individuals living in helminth-endemic regions are understudied. The Orang Asli, an indigenous population in Malaysia with high burdens of the helminth Trichuris trichiura, displayed microbiotas enriched in Clostridiales, an order of spore-forming obligate anaerobes previously shown to have immunogenic properties. We previously isolated novel Clostridiales that were enriched in these individuals and found that a subset promoted the Trichuris life cycle. Here, we further characterized the functional properties of these bacteria. Enzymatic and metabolomic profiling revealed a range of activities associated with metabolism and host response. Consistent with this finding, monocolonization of mice with individual isolates identified bacteria that were potent inducers of regulatory T cell (Treg) differentiation in the colon. Comparisons between variables revealed by these studies identified enzymatic properties correlated with Treg induction and Trichuris egg hatching. These results provide functional insights into the microbiotas of an understudied population.

Longitudinal Analysis of the Impacts of Urogenital Schistosomiasis on the Gut microbiota of Adolescents in Nigeria

The gut microbiome is important for many host physiological processes and helminths and these interactions may lead to microbial changes. We carried out a longitudinal study of the impacts of S. haematobium infection on the gut microbiome of adolescents (11-15 years) in northern Nigeria pre and post praziquantel treatment. Using 16S sequencing a total of 267 DNA from faecal samples of infected versus uninfected adolescents were amplified and sequenced on an Illumina Miseq. We assessed the diversity of the taxa using alpha diversity metrices and observed that using Shannon index we obtained significant differences when we compared infected samples at 3, 9 and 12 months to baseline uninfected controls (P= <0.0001, P=0.0342 and P=0.0003 respectively). Microbial community composition analysis revealed that there were only significant differences at 3, 9 and 12 months (P=0.001, P=0.001, P=0.001 and P=0.001, respectively). We also demonstrated that the effects of the infection on the gut was more significant than praziquantel. Overall, our data suggests that S. haematobium, a non-gut resident parasite has indirect interactions with the gut. The bacterial taxa changes we have identified opens up the opportunity to investigate their role in human health, especially in urogenital schistosomiasis endemic communities.

Dangerous liaisons: how helminths manipulate the intestinal epithelium

Intestinal helminths remain highly pervasive throughout the animal kingdom by modulating multiple aspects of the host immune response. The intestinal epithelium functions as a physical barrier as well as a sentinel innate immune tissue with the ability to sense and respond to infectious agents. Although helminths form intimate interactions with the epithelium, comprehensive knowledge about host-helminth interactions at this dynamic interface is lacking. In addition, little is known about the ability of helminths to directly shape the fate of this barrier tissue. Here, we review the diverse pathways by which helminths regulate the epithelium and highlight the emerging field of direct helminth regulation of intestinal stem cell (ISC) fate and function.

Networking between helminths, microbes, and mammals

Just as mammals have coevolved with the intestinal bacterial communities that are part of the microbiota, intestinal helminths represent an important selective force on their mammalian host. The complex interaction between helminths, microbes, and their mammalian host is likely an important determinant of mutual fitness. The host immune system in particular is a critical interface with both helminths and the microbiota, and this crosstalk often determines the balance between tolerance and resistance against these widespread parasites. Hence, there are many examples of how both helminths and the microbiota can influence tissue homeostasis and homeostatic immunity. Understanding these processes at a cellular and molecular level is an exciting area of research that we seek to highlight in this review and that will potentially guide future treatment approaches.

The ins and outs of innate and adaptive type 2 immunity

Type 2 immunity is orchestrated by a canonical group of cytokines primarily produced by innate lymphoid cells, group 2, and their adaptive counterparts, CD4+ helper type 2 cells, and elaborated by myeloid cells and antibodies that accumulate in response. Here, we review the cytokine and cellular circuits that mediate type 2 immunity. Building from insights in cytokine evolution, we propose that innate type 2 immunity evolved to monitor the status of microbe-rich epithelial barriers (outside) and sterile parenchymal borders (inside) to meet the functional demands of local tissue, and, when necessary, to relay information to the adaptive immune system to reinforce demarcating borders to sustain these efforts. Allergic pathology likely results from deviations in local sustaining units caused by alterations imposed by environmental effects during postnatal developmental windows and exacerbated by mutations that increase vulnerabilities. This framework positions T2 immunity as central to sustaining tissue repair and regeneration and provides a context toward understanding allergic disease.

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.

Helminth-associated changes in host immune phenotype connect top-down and bottom-up interactions during co-infection

1. Within-host parasite interactions can be mediated by the host and changes in host phenotypes often serve as indicators of the presence or intensity of parasite interactions. 2. Parasites like helminths induce a range of physiological, morphological, and immunological changes in hosts that can drive bottom-up (resource-mediated) or top-down (immune-mediated) interactions with co-infecting parasites. Although top-down and bottom-up interactions are typically studied in isolation, the diverse phenotypic changes induced by parasite infection may serve as a useful tool for understanding if, and when, these processes act in concert. 3. Using an anthelmintic treatment study of African buffalo (Syncerus caffer), we tracked changes in host immunological and morphological phenotypes during helminth-coccidia co-infection to investigate their role in driving independent and combinatorial bottom-up and top-down parasite interactions. We also examined repercussions for host fitness. 4. Clearance of a blood-sucking helminth, Haemonchus, from the host gastrointestinal tract induced a systemic Th2 immune phenotype, while clearance of a tissue-feeding helminth, Cooperia, induced a systemic Th1 phenotype. Furthermore, the Haemonchus-associated systemic Th2 immune phenotype drove simultaneous top-down and bottom-up effects that increased coccidia shedding by changing the immunological and morphological landscapes of the intestine. 5. Higher coccidia shedding was associated with lower host body condition, a lower chance of pregnancy, and older age at first pregnancy, suggesting that coccidia infection imposed significant condition and reproductive costs on the host. 6. Our findings suggest that top-down and bottom-up interactions may commonly co-occur and that tracking key host phenotypes that change in response to infection can help uncover complex pathways by which parasites interact.

Bacterial contact induces polar plug disintegration to mediate whipworm egg hatching

The bacterial microbiota promotes the life cycle of the intestine-dwelling whipworm Trichuris by mediating hatching of parasite eggs ingested by the mammalian host. Despite the enormous disease burden associated with Trichuris colonization, the mechanisms underlying this transkingdom interaction have been obscure. Here, we used a multiscale microscopy approach to define the structural events associated with bacteria-mediated hatching of eggs for the murine model parasite Trichuris muris . Through the combination of scanning electron microscopy (SEM) and serial block face SEM (SBFSEM), we visualized the outer surface morphology of the shell and generated 3D structures of the egg and larva during the hatching process. These images revealed that exposure to hatching-inducing bacteria catalyzed asymmetric degradation of the polar plugs prior to exit by the larva. Although unrelated bacteria induced similar loss of electron density and dissolution of the structural integrity of the plugs, egg hatching was most efficient in the presence of bacteria that bound poles with high density such as Staphylococcus aureus . Consistent with the ability of taxonomically distant bacteria to induce hatching, additional results suggest chitinase released from larva within the eggs degrade the plugs from the inside instead of enzymes produced by bacteria in the external environment. These findings define at ultrastructure resolution the evolutionary adaptation of a parasite for the microbe-rich environment of the mammalian gut.

Amino acid availability acts as a metabolic rheostat to determine the magnitude of ILC2 responses

Group 2 innate lymphoid cells (ILC2) are functionally poised, tissue-resident lymphocytes that respond rapidly to damage and infection at mucosal barrier sites. ILC2 reside within complex microenvironments where they are subject to cues from both the diet and invading pathogens-including helminths. Emerging evidence suggests ILC2 are acutely sensitive not only to canonical activating signals but also perturbations in nutrient availability. In the context of helminth infection, we identify amino acid availability as a nutritional cue in regulating ILC2 responses. ILC2 are found to be uniquely preprimed to import amino acids via the large neutral amino acid transporters Slc7a5 and Slc7a8. Cell-intrinsic deletion of these transporters individually impaired ILC2 expansion, while concurrent loss of both transporters markedly impaired the proliferative and cytokine-producing capacity of ILC2. Mechanistically, amino acid uptake determined the magnitude of ILC2 responses in part via tuning of mTOR. These findings implicate essential amino acids as a metabolic requisite for optimal ILC2 responses within mucosal barrier tissues.

The helminth holobiont: a multidimensional host-parasite-microbiota interaction

Gastrointestinal helminths have developed multiple mechanisms by which they manipulate the host microbiome to make a favorable environment for their long-term survival. While the impact of helminth infections on vertebrate host immunity and its gut microbiota is relatively well studied, little is known about the structure and functioning of microbial populations supported by metazoan parasites. Here we argue that an integrated understanding of the helminth-associated microbiome and its role in the host disease pathogenesis may facilitate the discovery of specific microbial and/or genetic patterns critical for parasite biology and subsequently pave the way for the development of alternative control strategies against parasites and parasitic disease.

Species interactions, stability, and resilience of the gut microbiota - Helminth assemblage in horses

The nature and strength of interactions entertained among helminths and their host gut microbiota remain largely unexplored. Using 40 naturally infected Welsh ponies, we tracked the gut microbiota-cyathostomin temporal dynamics and stability before and following anthelmintic treatment and the associated host blood transcriptomic response. High shedders harbored 14 species of cyathostomins, dominated by Cylicocyclus nassatus. They exhibited a highly diverse and temporal dynamic gut microbiota, with butyrate-producing Clostridia likely driving the ecosystem steadiness and host tolerance toward cyathostomins infection. However, anthelmintic administration sharply bent the microbial community. It disrupted the ecosystem stability and the time-dependent network of interactions, affecting longer term microbial resilience. These observations highlight how anthelmintic treatments alter the triangular relationship of parasite, host, and gut microbiota and open new perspectives for adding nutritional intervention to current parasite management strategies.

Infection-elicited microbiota promotes host adaptation to nutrient restriction

The microbiota performs multiple functions vital to host fitness, including defense against pathogens and adaptation to dietary changes. Yet, how environmental challenges shape microbiota resilience to nutrient fluctuation remains largely unexplored. Here, we show that transient gut infection can optimize host metabolism toward the usage of carbohydrates. Following acute infection and clearance of the pathogen, mice gained more weight as a result of white adipose tissue expansion. Concomitantly, previously infected mice exhibited enhanced carbohydrate (glucose) disposal and insulin sensitivity. This metabolic remodeling depended on alterations to the gut microbiota, with infection-elicited Betaproteobacteria being sufficient to enhance host carbohydrate metabolism. Further, infection-induced metabolic alteration protected mice against stunting in the context of limited nutrient availability. Together, these results propose that alterations to the microbiota imposed by acute infection may enhance host fitness and survival in the face of nutrient restriction, a phenomenon that may be adaptive in settings where both infection burden and food precarity are prevalent.

Neglected gut microbiome: interactions of the non-bacterial gut microbiota with enteric pathogens

A diverse array of commensal microorganisms inhabits the human intestinal tract. The most abundant and most studied members of this microbial community are undoubtedly bacteria. Their important role in gut physiology, defense against pathogens, and immune system education has been well documented over the last decades. However, the gut microbiome is not restricted to bacteria. It encompasses the entire breadth of microbial life: viruses, archaea, fungi, protists, and parasitic worms can also be found in the gut. While less studied than bacteria, their divergent but important roles during health and disease have become increasingly more appreciated. This review focuses on these understudied members of the gut microbiome. We will detail the composition and development of these microbial communities and will specifically highlight their functional interactions with enteric pathogens, such as species of the family Enterobacteriaceae. The interactions can be direct through physical interactions, or indirect through secreted metabolites or modulation of the immune response. We will present general concepts and specific examples of how non-bacterial gut communities modulate bacterial pathogenesis and present an outlook for future gut microbiome research that includes these communities.

Gut microbiota of endangered Australian sea lion pups is unchanged by topical ivermectin treatment for endemic hookworm infection

The gut microbiota is essential for the development and maintenance of the hosts' immune system. Disturbances to the gut microbiota in early life stages can result in long-lasting impacts on host health. This study aimed to determine if topical ivermectin treatment for endemic hookworm (Uncinaria sanguinis) infection in endangered Australian sea lion (Neophoca cinerea) pups resulted in gut microbial changes. The gut microbiota was characterised for untreated (control) (n = 23) and treated (n = 23) Australian sea lion pups sampled during the 2019 and 2020/21 breeding seasons at Seal Bay, Kangaroo Island. Samples were collected pre- and post-treatment on up to four occasions over a four-to-five-month period. The gut microbiota of untreated (control) and treated pups in both seasons was dominated by five bacterial phyla, Fusobacteria, Firmicutes, Proteobacteria, Actinobacteria and Bacteroidetes. A significant difference in alpha diversity between treatment groups was seen in pups sampled during the 2020/21 breeding season (p = 0.008), with higher richness and diversity in treated pups. Modelling the impact of individual pup identification (ID), capture, pup weight (kg), standard length (cm), age and sex on beta diversity revealed that pup ID accounted for most of the variation (35% in 2019 and 42% in 2020/21), with pup ID, capture, and age being the only significant contributors to microbial variation (p < 0.05). There were no statistically significant differences in the composition of the microbiota between treatment groups in both the 2019 and 2020/21 breeding seasons, indicating that topical ivermectin treatment did not alter the composition of the gut microbiota. To our knowledge, this is the first study to characterise the gut microbiota of free-ranging Australian pinniped pups, compare the composition across multiple time points, and to consider the impact of parasitic treatment on overall diversity and microbial composition of the gut microbiota. Importantly, the lack of compositional changes in the gut microbiota with treatment support the utility of topical ivermectin as a safe and minimally invasive management strategy to enhance pup survival in this endangered species.

Gut microbiome of helminth-infected indigenous Malaysians is context dependent

BACKGROUND

While microbiomes in industrialized societies are well characterized, indigenous populations with traditional lifestyles have microbiomes that are more akin to those of ancient humans. However, metagenomic data in these populations remains scarce, and the association with soil-transmitted helminth infection status is unclear. Here, we sequenced 650 metagenomes of indigenous Malaysians from five villages with different prevalence of helminth infections.

RESULTS

Individuals from villages with higher prevalences of helminth infections have more unmapped reads and greater microbial diversity. Microbial community diversity and composition were most strongly associated with different villages and the effects of helminth infection status on the microbiome varies by village. Longitudinal changes in the microbiome in response to albendazole anthelmintic treatment were observed in both helminth infected and uninfected individuals. Inference of bacterial population replication rates from origin of replication analysis identified specific replicating taxa associated with helminth infection.

CONCLUSIONS

Our results indicate that helminth effects on the microbiota were highly dependent on context, and effects of albendazole on the microbiota can be confounding for the interpretation of deworming studies. Furthermore, a substantial quantity of the microbiome remains unannotated, and this large dataset from an indigenous population associated with helminth infections is a valuable resource for future studies. Video Abstract.

Effects of challenge with Clostridium perfringens, Eimeria and both on ileal microbiota of yellow feather broilers

In the poultry industry worldwide, Clostridium perfringens has been causing major economic loss as it can cause necrotic enteritis (NE). The coccidial infection has been considered as the most important predisposing factor of NE caused by C. perfringens. In this study, we aimed to advance our knowledge on ileal microbiota of yellow feather broilers under C. perfringens and/or Eimeria challenge. Total of 80 healthy day old yellow feather broilers were randomly assigned to four groups including: Control, C. perfringens challenge group (C. Per), Eimeria challenge group (Cocc), and C. perfringens plus Eimeria challenge group (Comb). On day 14, the Cocc and Comb group broilers were orally gavaged 1 ml PBS solution containing 25,000 oocysts of Eimeria brunetti and 25,000 oocysts of Eimeria maxima. Starting on day 17, the C. Per and Comb group broilers were orally gavaged 10 mL of C. perfringens per bird (4 × 107 CFU/mL, ATCC® 13124™ Strain) every day for 6 days. 16S rRNA gene sequencing was performed on extracted DNA of ileal digesta samples. The results showed that C. perfringens alone did not affect the alpha diversity of ileal microbiome in yellow feather broilers but co-infection with Eimeria significantly decreased the diversity of ileal microbiota. C. perfringens and Eimeria challenge also decreased the relative abundance of beneficial bacteria including Bacteroidetes at the phylum level and Faecalibacterium at the genus level. At the species level, the relative abundance of Candidatus Arthromitus was significantly decreased in the Eimeria challenged groups. This microbial shift information of ileal microbiota under C. Perfringens and Eimeria challenge provide important reference data for the development of therapeutic approaches to necrotic enteritis in yellow-feather broiler chickens.

Early-Life Mebendazole Exposure Increases the Risk of Adult-Onset Ulcerative Colitis: A Population-Based Cohort Study

INTRODUCTION

According to the hygiene hypothesis, exposure to parasites may protect against inflammatory bowel disease (IBD). Our aim was to examine the risk of IBD with childhood exposure to mebendazole, a broad-spectrum antihelminthic agent.

METHODS

We conducted a population-based cohort study using prospectively collected historical data of all individuals born in Denmark between 1995 and 2018. We identified mebendazole exposure at age younger than 18 years and during early life (younger than 5 years). We performed adjusted Cox proportional hazards regression analysis to determine the risk of IBD, ulcerative colitis (UC), and Crohn's disease with mebendazole exposure after adjusting for potential confounders.

RESULTS

Of 1,520,290 individuals in the cohort, 615,794 had childhood or adolescence mebendazole exposure. One thousand five hundred fifty-five and 1,499 individuals were subsequently diagnosed with pediatric-onset and adult-onset IBD, respectively. On multivariable analysis, mebendazole exposure at age younger than 18 years did not affect pediatric-onset or adult-onset IBD risk (adjusted hazard ratio [aHR] 0.97, 95% confidence interval [CI] 0.87, 1.07, and 1.08, 95% CI 0.97, 1.19, respectively). On limiting mebendazole exposure to age younger than 5 years while there was no association with pediatric-onset IBD (aHR 0.98, 95% CI 0.87, 1.11), adult-onset IBD risk was increased (aHR 1.17, 95% CI 1.04, 1.31). This increase in risk was driven by UC (aHR 1.32, 95% CI 1.12, 1.55), but not Crohn's disease (1.03, 95% CI 0.87, 1.22).

DISCUSSION

Early-life mebendazole exposure is associated with an increase in the risk of adult-onset UC. These findings suggest the importance of early-life exposures in shaping the risk of IBD later in life.

Clostridia isolated from helminth-colonized humans promote the life cycle of Trichuris species

Soil-transmitted intestinal worms known as helminths colonize over 1.5 billion people worldwide. Although helminth colonization has been associated with altered composition of the gut microbiota, such as increases in Clostridia, individual species have not been isolated and characterized. Here, we isolate and sequence the genome of 13 Clostridia from the Orang Asli, an indigenous population in Malaysia with a high prevalence of helminth infections. Metagenomic analysis of 650 fecal samples from urban and rural Malaysians confirm the prevalence of species corresponding to these isolates and reveal a specific association between Peptostreptococcaceae family members and helminth colonization. Remarkably, Peptostreptococcaceae isolated from the Orang Asli display superior capacity to promote the life cycle of whipworm species, including hatching of eggs from Trichuris muris and Trichuris trichiura. These findings support a model in which helminths select for gut colonization of microbes that support their life cycle.

Echinococcus granulosus sensu stricto and antigen B may decrease inflammatory bowel disease through regulation of M1/2 polarization

Background

Inflammatory bowel disease (IBD) is a chronic idiopathic disease characterized by inflammation-related epithelial barrier damage in the intestinal tract. Helminth infection reduces autoimmune disease symptoms through regulation of inflammatory responses based on hygiene theory. However, the underlying mechanisms remain unclear.

Methods

BALB/c mice were infected with microcysts of E. granulosus sensu stricto and drank water containing 3.5% dextran sodium sulfate (DSS) at the 100th day post-infection. After 7 days of drinking DSS, the mouse body weight change and disease activity index (DAI) were recorded every day, and colon length and histological score were evaluated after sacrifice. After injection with antigen B (AgB), inducible nitric oxide synthase (iNOS) and Fizz1 expression and F4/80⁺CD11c⁺ M1 and F4/80⁺CD206⁺ M2 in the peritoneal cells and colon tissues were analysed by qPCR and flow cytometry, respectively. Gut microbiota were profiled by 16S rRNA sequencing of the mouse faecal samples. For in vitro assay, RAW264.7 macrophages were cultured in medium containing AgB before induction by lipopolysaccharide (LPS). Then, NO in the supernatant was measured, and the expression of cytokine genes associated with macrophages were determined by qRT-PCR.

Results

Echinococcus granulosus s.s. infection and AgB significantly reduced the symptoms and histological scores of IBD induced by DSS (P < 0.05). Flow cytometry showed that AgB inoculation increased F4/80⁺ and CD206⁺ in peritoneal cells. The results of qPCR showed that AgB significantly decreased iNOS and increased Fizz1 expression in the colon of mice inoculated by DSS (P < 0.05). Furthermore, AgB injection led to significant changes in the profiles of five genera (Paraprevotella, Odoribacter, Clostridium cluster XlVa, Oscillibacter, and Flavonifractor) in faecal samples. In vitro analysis showed that AgB reduced NO levels (P < 0.01), with a significant decrease in iNOS expression (P < 0.05) in RAW264.7 cells induced by LPS.

Conclusions

Echinococcus granulosus infection and AgB may improve IBD conditions by inducing an M2-predominant cellular (F4/80⁺ CD206⁺) profile and decreasing type 1 macrophages (F4/80⁺CD11c⁺) in the intestinal lamina propria. In addition, AgB intervention induced changes in the microbiota condition of the gastrointestinal duct and reversed NO expression. Thus, AgB may be a drug candidate for IBD treatment.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05498-y.

Limited microbiome differences in captive and semi-wild primate populations consuming similar diets

Gut microbial communities are shaped by a myriad of extrinsic factors, including diet and the environment. Although distinct human populations consistently exhibit different gut microbiome compositions, variation in diet and environmental factors are almost always coupled, making it difficult to disentangle their relative contributions to shaping the gut microbiota. Data from discrete animal populations with similar diets can help reduce confounds. Here, we assessed the gut microbiota of free-ranging and captive rhesus macaques with at least 80% diet similarity to test the hypothesis that hosts in difference environments will have different gut microbiomes despite a shared diet. Although we found that location was a significant predictor of gut microbial composition, the magnitude of observed differences was relatively small. These patterns suggest that a shared diet may limit the typical influence of environmental microbial exposure on the gut microbiota.

Efficacy of triple dose albendazole treatment for soil-transmitted helminth infections

In Malaysia, soil-transmitted helminth (STH) infections still persist among indigenous communities. In the past, local studies have focused mostly on epidemiologic aspects of STH infections with a scarcity of information on the efficacy of deworming treatment. The present study consisted of 2 phases: a cross-sectional phase on current epidemiological status and risk factors of STH infections and a longitudinal study over 6 weeks on triple dose albendazole efficacy against STH infections. A total of 253 participants were recruited at baseline and a pre-tested questionnaire was administered to obtain information on socio-demographics, environmental and behavioural risk factors. Stool samples were evaluated using a modified Kato-Katz technique. Cure rate (CR) and egg reduction rate (ERR) were assessed at 3 weeks following a 3-day course of 400mg albendazole treatment and infection status were observed again at 6 weeks. Baseline positivity of trichuriasis, ascariasis and hookworm infections were 56.1%, 11.9% and 20.2%, respectively. Multivariate analysis showed age below 18 years old (P = 0.004), without latrine in house (P = 0.042) and indiscriminate defecation (P = 0.032) were associated with STH infections. In the longitudinal study (N = 89), CR for trichuriasis was 64.6%, while CR of 100% was observed for both ascariasis and hookworm. ERR was above 90% for all three STH species. A rapid increased of Trichuris trichiura egg output was observed at 6 weeks. In conclusion, STH infections are highly prevalent among indigenous communities. Children and teenagers, poor sanitation and hygiene behaviour were determinants for STH infections. Triple dose albendazole is found to be efficacious against Ascaris lumbricoides and hookworm infections but has moderate curative effect with high ERR against T. trichiura. Although triple dose albendazole regimen has logistic challenges and may not be a routine option, consideration of this treatment regime may still be necessary in selective communities to reduce high intensity of T. trichiura infection.

Differences in microbiome of healthy Sprague Dawley rats with Paragonimus proliferus infection and potential pathogenic role of microbes in paragonimiasis

Paragonimiasis, which is caused by Paragonimus, is considered to be a neglected tropical disease by the World Health Organization. The pathogenicity of Paragonimus mainly manifests as mechanical damage and immunotoxicity caused by adult worms and larvae. However, microbiota associated with Paragonimus and potential disturbance of host microbiota after infection are unknown. Paragonimus proliferus is a rare species, and its successful infection rate in experimental rats is 100%. In the current study, we compared the microbial community in lung tissues, small intestine contents, and fecal samples from Sprague Dawley (SD) rats with and without P. proliferus infection. To determine the impact of P. proliferus on the microbial community in rats, we identified the microbiota in adult worms of P. proliferus via high-throughput sequencing. Results showed dramatic differences in the composition of microbiota in lung tissues between infected and uninfected rats. Paragonimus metacercariae introduced both environmental and gut microbes into the lung tissues of rats. Many potentially pathogenic microbes were also found in the lung of infected rats. Paragonimus infection increased the chances of potentially pathogenic microbiota invading and colonizing the lungs. However, for the purpose of long-term parasitism, there might be a complex interrelationship between Paragonimus and microorganisms. Our study might shed lights on the understanding of the pathogenicity of Paragonimus.

Clinical helminth infections alter host gut and saliva microbiota

Background

Previous reports show altered gut bacterial profiles are associated with helminth infected individuals. Our recently published molecular survey of clinical helminthiases in Thailand border regions demonstrated a more comprehensive picture of infection prevalence when Kato Katz microscopy and copro-qPCR diagnostics were combined. We revealed that Opisthorchis viverrini, hookworm, Ascaris lumbricoides and Trichuris trichiura were the most predominant helminth infections in these regions. In the current study, we have profiled the faecal and saliva microbiota of a subset of these helminth infected participants, in order to determine if microbial changes are associated with parasite infection.

Methods

A subset of 66 faecal samples from Adisakwattana et al., (2020) were characterised for bacterial diversity using 16S rRNA gene profiling. Of these samples a subset of 24 participant matched saliva samples were also profiled for microbiota diversity. Sequence data were compiled, OTUs assigned, and diversity and abundance analysed using the statistical software Calypso.

Results

The data reported here indicate that helminth infections impact on both the host gut and oral microbiota. The profiles of faecal and saliva samples, irrespective of the infection status, were considerably different from each other, with more alpha diversity associated with saliva (p-value≤ 0.0015). Helminth infection influenced the faecal microbiota with respect to specific taxa, but not overall microbial alpha diversity. Conversely, helminth infection was associated with increased saliva microbiota alpha diversity (Chao 1 diversity indices) at both the genus (p-value = 0.042) and phylum (p-value = 0.026) taxa levels, compared to uninfected individuals. Elevated individual taxa in infected individuals saliva were noted at the genus and family levels. Since Opisthorchis viverrini infections as a prominent health concern to Thailand, this pathogen was examined separately to other helminths infections present. Individuals with an O. viverrini mono-infection displayed both increases and decreases in genera present in their faecal microbiota, while increases in three families and one order were also observed in these samples.

Discussion

In this study, helminth infections appear to alter the abundance of specific faecal bacterial taxa, but do not impact on overall bacterial alpha or beta diversity. In addition, the faecal microbiota of O. viverrini only infected individuals differed from that of other helminth single and dual infections. Saliva microbiota analyses of individuals harbouring active helminth infections presented increased levels of both bacterial alpha diversity and abundance of individual taxa. Our data demonstrate that microbial change is associated with helminthiases in endemic regions of Thailand, and that this is reflected in both faecal and saliva microbiota. To our knowledge, this is the first report of an altered saliva microbiota in helminth infected individuals. This work may provide new avenues for improved diagnostics; and an enhanced understanding of both helminth infection pathology and the interplay between helminths, bacteria and their host.

Microbial byproducts determine reproductive fitness of free-living and parasitic nematodes

Trichuris nematodes reproduce within the microbiota-rich mammalian intestine and lay thousands of eggs daily, facilitating their sustained presence in the environment and hampering eradication efforts. Here, we show that bacterial byproducts facilitate the reproductive development of nematodes. First, we employed a pipeline using the well-characterized, free-living nematode C. elegans to identify microbial factors with conserved roles in nematode reproduction. A screen for E. coli mutants that impair C. elegans fertility identified genes in fatty acid biosynthesis and ethanolamine utilization pathways, including fabH and eutN. Additionally, Trichuris muris eggs displayed defective hatching in the presence of fabH- or eutN-deficient E. coli due to reduced arginine or elevated aldehydes, respectively. T. muris reared in gnotobiotic mice colonized with these E. coli mutants displayed morphological defects and failed to lay viable eggs. These findings indicate that microbial byproducts mediate evolutionarily conserved transkingdom interactions that impact the reproductive fitness of distantly related nematodes.

Effects of helminths on the human immune response and the microbiome

Helminths have evolved sophisticated immune regulating mechanisms to prevent rejection by their mammalian host. Our understanding of how the human immune system responds to these parasites remains poor compared to mouse models of infection and this limits our ability to develop vaccines as well as harness their unique properties as therapeutic strategies against inflammatory disorders. Here, we review how recent studies on human challenge infections, self-infected individuals, travelers, and endemic populations have improved our understanding of human type 2 immunity and its effects on the microbiome. The heterogeneity of responses between individuals and the limited access to tissue samples beyond the peripheral blood are challenges that limit human studies on helminths, but also provide opportunities to transform our understanding of human immunology. Organoids and single-cell sequencing are exciting new tools for immunological analysis that may aid this pursuit. Learning about the genetic and immunological basis of resistance, tolerance, and pathogenesis to helminth infections may thus uncover mechanisms that can be utilized for therapeutic purposes.

Functional Diversity of the Excretory/Secretory Proteins of Nematode Parasites

INTRODUCTION

Parasites release a wide array of protein as excretory and secretory products (ESPs). Irrespective of their mode of propagation, ESPs are found to be secreted or excreted by both naturally occurring and laboratory-cultivated parasites. Mass spectrometry-based approaches have been extensively used to identify and characterize the ESP constituents. ESPs are involved in various cellular activities such as immune modulation, proteolysis, inhibition of proteases and protection of cells against oxidants. Specifically, their role in host immune evasion by down-regulation of pro-inflammatory cytokines and up-regulation of anti-inflammatory cytokines attracts scientific attention. A thorough investigation of functional diversity of ESPs may be helpful in planning control strategies against many parasites.

METHODS

This review focuses on diversity of ES proteins, various approaches to identify them and discusses about the biochemical and functional aspects of such proteins.

RESULTS

The diverse array of proteins secreted or excreted (a, GST-1, acetylcholinesterase, GAPDH) by the parasites are also described emphasizing their role in cellular physiology.

CONCLUSION

Finally, it concludes by citing some of these proteins as potential therapeutic agents against helminth challenge.