Biology subjects

Grencis, R. K.

Publications and source records attributed to Grencis, R. K..

14 recordsLinked to original sources

bioRxiv2025

Caecal epithelium-derived thymic stromal lymphopoietin is not required for protective immunity against whipworm

Recent research examining classical type two alarmin TSLP has uncovered non-epithelial cellular sources of the cytokine during various murine challenges. Trichuris muris is a key model of type two immunity in the intestine with expulsion being TSLP-dependent. Previous research was suggestive of epithelial production of TSLP in the caecum, but its production during infection has not been characterised in detail. Here, using qPCR, transcript-based imaging, and conditional knockout, we demonstrate caecal epithelium to be a poor source of Tslp, and that non-epithelial upregulation occurs during Trichuris infection, peaking around day 14 post-infection. Conditional knockout of TSLP expression in caecal epithelial cells did not here impact parasite expulsion, but, surprisingly, neutralisation of TSLP from days 15 to 25 produced full susceptibility. These data build on previous work to raise important questions regarding the interaction of TSLP with immunity broadly, as well as the conditions for production of immunity to intestinal helminths.

immunology↗

bioRxiv2025

Host microbiome determines host specificity of the human whipworm, Trichuris trichiura

Long-term whipworm-host co-evolution has resulted in tropism for the caecum of specific hosts, an organ with the densest microbial population in the body. Here, we demonstrate that the host specificity of human whipworms (Trichuris trichiura) is host microbiome-driven. We successfully establish a T. trichiura infection in a non-primate host using a humanised-microbiota mouse model. We further show, in vitro, that hatching of T. trichiura was triggered by mucosal scrapings of the caecum of human microbiota-associated mice, but not from wild-type mice, which only induced T. muris hatching. Comparative metagenomic analysis of the murine versus humanised microbiomes directly implicated specific bacterial species in T. trichiura egg hatching. Additionally, we demonstrate that host tissue does not directly determine host specificity, as T. trichiura readily infected mouse caecaloids. Our findings indicate that host-microbiome-whipworm co-evolution has resulted in exquisite bacterial-whipworm egg interactions critical for hatching and development of these parasites in their definitive hosts.

microbiology↗

bioRxiv2025

The immunomodulatory p43 secreted protein of Trichuris whipworm parasites is a lipid carrier that binds signalling lipids and precursors

Parasitic helminths such as the Trichuris whipworms contribute to significant disease and morbidity in humans and other animals. They cause prolonged infections despite intact immune systems of their hosts, and their persistence is increasingly attributed to immunomodulatory activities of their secreted products. We examined the p43 (Tm-DLP-1) protein of Trichuris muris that comprises about 95% of the protein secreted by the adult parasite, is known to bind matrix proteoglycans, and have IL-13-neutralising activity. We show here that worm-derived p43 purified from secretions binds fatty acids and retinol, including signalling lipids or precursors thereof. This binding activity might therefore contribute to the parasites modulation of the infection site by delivering or sequestering influential lipids. A recombinant orthologue of p43 from the human whipworm, Trichuris trichiura (p47; Tt-DLP-1), has similar lipid-binding activity, with a similarly highly apolar biding site. From the known molecular structure of p43, we note the existence of extensive surface-accessible cavities with diverse surface charge characteristics which may indicate binding of a range of small molecule types in addition to lipids, and that its internally duplicated subdomains likely possess discrete characteristics. p43 belongs to the "dorylipophorins" that have only been found in Dorylaimia (Clade I) nematodes and appear to be the chief lipid carrier in their pseudocoelomic fluids, replacing the major lipid transporters of other nematode clades. In T. muris, and potentially other trichurids, these molecules appear to have been adapted for both internal physiological and external immunomodulatory activities.

biochemistry↗

bioRxiv2024

Hatching of whipworm eggs induced by bacterial contact is serine-protease dependent

Whipworms (Trichuris spp) are ubiquitous parasites of humans and domestic and wild mammals that cause chronic disease, considerably impacting human and animal health. Egg hatching is a critical phase in the whipworm life cycle that marks the initiation of infection, with newly hatched larvae rapidly migrating to and invading host intestinal epithelial cells. Hatching is triggered by the host microbiota; however, the physical and chemical interactions between bacteria and whipworm eggs, as well as the bacterial and larval responses that result in the disintegration of the polar plug and larval eclosion, are not completely understood. Here, we examined hatching in the murine whipworm, Trichuris muris, and investigated the role of specific bacterial and larval structures and molecules in this process. Using scanning and transmission electron microscopy, we characterised the physical interactions of both fimbriated (Escherichia coli, Salmonella typhimurium and Pseudomonas aeruginosa) and non-fimbriated (Staphylococcus aureus) bacteria with the egg polar plugs during the induction/initiation stage and visualised the process of degradation of the polar plugs that leads to larval eclosion. Further, we found that protease inhibitors blocked whipworm hatching induced by both fimbriated and non-fimbriated bacteria in a dose-dependent manner, suggesting the partial involvement of bacterial enzymes in this process. In addition, we identified the minimal egg developmental timing required for whipworm hatching, and transcriptomic analysis of T. muris eggs through embryonation revealed the specific upregulation of serine proteases (S01A family) in fully embryonated eggs containing hatch-ready L1 larvae. Finally, we demonstrated that inhibition of serine proteases with the serine-protease inhibitor Pefabloc ablated T. muris egg hatching induced by bacteria. Collectively, our findings unravel the temporal and physicochemical bacterial-egg interactions leading to whipworm hatching and indicate serine proteases of both bacterial and larval origin mediate these processes. Author summaryHuman whipworms are parasites that cause the gastrointestinal disease trichuriasis in millions of people around the world. Infections occur when whipworm eggs, ingested in contaminated food and water, hatch in the intestine in response to gut bacteria (microbiota). The egg encloses a larva within an egg-shell and has a plug at each end. Hatching liberates the larva that burrows inside the cells that line the gut. Interactions between the microbiota of the gut and whipworm eggs are needed for hatching but are poorly understood. In this study, using the natural mouse whipworm as an infection model, we show that bacteria bind the whipworm egg plugs during the initial stages of hatching, resulting in their degradation and leading to larval exit. We further show that disintegration of the egg plugs is caused by protein-degrading enzymes produced by the bacteria and the larvae. The production of those enzymes by the parasite is dependent on the full development of the larva inside the whipworm egg. These new mechanistic insights pave the way for future studies to understand human whipworm infection and develop new tools to tackle these globally important parasites.

microbiology↗

bioRxiv2023

Myeloid A20 is critical for type-2 immune mediated helminth resistance

Protective immunity against intestinal helminths requires induction of robust Type-2 immunity orchestrated by various cellular and soluble effectors which promote goblet cell hyperplasia, mucus production, epithelial proliferation and smooth muscle contractions to expel worms and reestablish immune homeostasis. Conversely, defects in type-2 immunity result in ineffective helminth clearance, persistent infection and chronic inflammation. We identify A20 as an essential myeloid factor for the induction of type-2 immune responses against the intestinal parasite Trichuris muris. Myeloid cell-specific loss of A20 in mice (A20myel-KO) results in chronic Trichuris muris infection and intestinal inflammation. Myeloid A20 deficient mice are not able to induce anti-helmith type-2 immune responses while instead mount detrimental Th1/Th17 polarized immune responses. Antibody-mediated neutralization of the type-1 cytokines IFN{gamma}, IL18 and IL12 prevents Th1/Th17 polarization and reestablishes Type-2 mediated protective immunity against Trichuris muris in A20myel-KO mice. In contrast, the strong Th1/Th17 biased immunity in A20myel-KO mice offers protection against Salmonella infection. We hereby identify A20 as an essential myeloid factor to initiate approriate adaptive immunity in response to infection, and to induce a balanced type-2 immune response against the intestinal parasite Trichuris muris. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=140 SRC="FIGDIR/small/556360v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@632052org.highwire.dtl.DTLVardef@1def1f2org.highwire.dtl.DTLVardef@1de8459org.highwire.dtl.DTLVardef@1c316ff_HPS_FORMAT_FIGEXP M_FIG C_FIG Graphical abstractThe clearance of gastrointestinal helmiths depends on type-2 immunity. Helminths interact with and damage intestinal tissue, which leads to the release of intracellular DAMPs and cytokines such as TSLP and IL33, and IL25 produced by epithelial cells. These factors may activate myeloid cells and ILCs, which further activate T and B cells to mount effective Th2 responses and the secretion of IL4, IL5 and IL13 cytokines, as well as helminth-specific IgG1 immunoglobulins, leading to effective expulsion of the helminths. Deletion of A20 in the myeloid cells leads to enhanced secretion of type-1 cytokines, including IL12, IL18 and IFN{gamma}, which impede type-2 immune-mediated helminth clearance and promotes chronic intestinal inflammation.

immunology↗

bioRxiv2022

Increased gut microbial mucin foraging promotes clearance of a parasitic worm

BACKGROUND & AIMSHost-secreted gastrointestinal mucus plays a key role in the expulsion of intestinal nematode parasites. A balance between mucin secretion by the host and the gut microbial mucin foraging is essential to maintain the intestinal homeostasis, yet little is known about how changes in the mucin-microbiome interactions affect worm infections. Here, we aimed to examine how mucin foraging activity by the microbiome changes the course of parasitic worm infections by modulating the host immune responses. METHODSWe utilized a gnotobiotic mouse model containing a synthetic human gut microbiota that allows for: 1) a complete removal of the mucin-degrading bacteria from the community; and 2) diet-driven manipulation of the microbiota toward mucin foraging. We infected mice with a murine nematode, Trichuris muris, which resembles human infection with Trichuris trichiura. We examined the temporal dynamics of worm infection including worm burden and the host immune responses, and coupled these readouts to the microbial changes and mucin foraging activity. RESULTSThe absence of mucin-degrading bacteria in the microbiota enhances susceptibility to parasitic infection--evidenced by higher worm number--by promoting stronger Th1 immune responses. Dietary fiber deprivation increases the microbial mucin-foraging activity, which coincides with a shift in host immune responses from susceptible (chronic, Th1 type) to resistant (acute, Th2 type), thereby promoting worm clearance. CONCLUSIONSOur results provide mechanistic insights into how the colonic mucin-degrading bacteria promote anti-parasitic immunity through modulation of the host immune responses. Our study documents a clinically-relevant, novel link in the microbiome-parasite-host immune axis that is useful prerequisite knowledge in managing parasitic infections.

immunology↗

bioRxiv2021

Rhythmicity of Intestinal IgA Responses Confers Oscillatory Commensal Microbiota Mutualism

Mutualistic interactions with the commensal microbiota are enforced through a range of immune responses that confer metabolic benefits for the host and ensure tissue health and homeostasis. Immunoglobulin (Ig)A responses directly determine the composition of commensal species that colonize the intestinal tract but require significant metabolic resources to fuel antibody production by tissue-resident plasma cells. Here we demonstrate IgA responses are subject to diurnal regulation by dietary-derived metabolic cues and a cell-intrinsic circadian clock. Rhythmicity in IgA secretion conferred oscillatory patterns on the commensal microbial community and its associated metabolic activity, resulting in changes to metabolite availability over the course of the circadian day. Our findings suggest circadian networks comprising intestinal IgA, the diet and the microbiota align to ensure metabolic health. One-Sentence SummaryWe demonstrate diurnal rhythms in intestinal IgA act to cross-regulate oscillations in the abundance of commensal microbes to foster mutualism.

immunology↗

bioRxiv2021

Sustained post-developmental T-bet expression is critical for the maintenance of type 1 innate lymphoid cells in vivo

Innate lymphoid cells (ILC) play a significant role in the intestinal immune response and T-bet+ CD127+ group 1 cells (ILC1) have been linked to the pathogenesis of human inflammatory bowel disease (IBD). However, the functional importance of ILC1 in the context of an intact adaptive immune response has been controversial. In this report we demonstrate that induced depletion of T-bet using a Rosa26-Cre-ERT2 model resulted in the loss of intestinal ILC1, pointing to a post-developmental requirement of T-bet expression for these cells. In contrast, neither colonic lamina propria (cLP) ILC2 nor cLP ILC3 abundance were altered upon induced deletion of T-bet. Mechanistically, we report that STAT1 or STAT4 are not required for intestinal ILC1 development and maintenance. Mice with induced deletion of T-bet and subsequent loss of ILC1 were protected from the induction of severe colitis in vivo. Hence, this study provides support for the clinical development of an IBD treatment based on ILC1 depletion via targeting T-bet or its downstream transcriptional targets.

immunology↗

bioRxiv2020

Large Neutral Amino acid uptake and mTOR activation within CD4+ T cells coordinate Type 2 immunity and host resistance to Trichuris muris

Trichuris trichiura (whipworm) is a gastrointestinal nematode that infects approximately 465 million people worldwide. T. muris is used as a tractable model for the human whipworm. In wild type mice, infection with a high dose of T. muris eggs leads to worm expulsion, which is dependent on a CD4+Th2 response and interleukin (IL-)13 production. It is known that T cells up-regulate glycolysis and uptake of substrates upon activation. The amino acid transporter SLC7A5 has been shown necessary for activation of mTORC1, a nutrient/energy/redox sensor critical for T cell differentiation into effector cells. We found that at the peak of the immune response to T. muris, mice lacking SLC7A5 in CD4+T cells have delayed worm expulsion, lower levels of IL-13, reduced pmTOR and glycolytic rates. However, at later stages of infection IL-13 levels partially recovered alongside resistance. The critical role of CD4+T cell metabolism per se and down-stream mTOR in CD4+T cells in resistance was shown in mice lacking mTOR in CD4+T cells, that failed to expel a high dose of parasites and developed chronic infection. Our study shows that mTOR is essential for effective functioning of T cells during whipworm infection and that deletion of Slc7a5 significantly delays worm clearance.

immunology↗

bioRxiv2020

Defining the early stages of intestinal colonisation by whipworms

Whipworms are large metazoan parasites that inhabit distinct multi-intracellular epithelial burrows described as syncytial tunnels, in the large intestine of their hosts. How first-stage larvae invade host epithelia and establish infection remains unclear. Here, we investigate early infection events both using Trichuris muris infections of mice and murine caecaloids, the first in-vitro system for whipworm infection. We show that larvae degrade the mucus layers to access epithelial cells. In early syncytial tunnels, larvae are completely intracellular but woven through multiple live enterocytes and goblet cells. We also use single cell RNA sequencing for the first time to describe the mouse caecum. From infected caeca, the transcriptome data reveal the progression of infection results in cell damage and an expansion of enterocytes with a type-I interferon (IFN) signature, characterised by the expression of Isg15, instigating the host immune response to the whipworm and tissue repair. Our results unravel intestinal epithelium invasion by whipworms and reveal new specific interactions between the host and the parasite that allow the whipworm to establish its multi-intracellular niche.

immunology↗

bioRxiv2020

Development of caecaloids to study host-pathogen interactions: new insights into immunoregulatory functions of Trichuris muris extracellular vesicles in the caecum

The caecum, an intestinal appendage in the junction of the small and large intestines, displays a unique epithelium that serves as an exclusive niche for a range of pathogens including whipworms (Trichuris spp). While protocols to grow organoids from small intestine (enteroids) and colon (colonoids) exist, the conditions to culture organoids from the caecum have yet to be described. Here, we report methods to grow, differentiate and characterise mouse adult stem cell-derived caecal organoids, termed caecaloids. We compare the cellular composition of caecaloids to that of enteroids identifying differences in intestinal epithelial cell (IEC) populations that mimic those found in the caecum and small intestine. The remarkable similarity in the IECs composition and spatial conformation of caecaloids and their tissue of origin enables their use as an in vitro model to study host interactions with important caecal pathogens. Thus, exploiting this system we investigated the responses of caecal IECs to extracellular vesicles (EVs) secreted/excreted by the intracellular helminth Trichuris muris. Our findings reveal novel immunoregulatory effects of whipworm EVs on the caecal epithelium, including the downregulation of responses to nucleic acid recognition and type-I interferon (IFN) signalling.

immunology↗

bioRxiv2019

IL-17A both initiates (via IFNγ suppression) and limits the pulmonary type 2 immune response to nematode infection

Nippostrongylus brasiliensis is a well-defined model of type-2 immunity but the early lung-migrating phase is dominated by innate IL-17A production and neutrophilia. Using N. brasiliensis infection we confirm previous observations that Il17a-KO mice exhibit an impaired type-2 immune response. Neutrophil depletion and reconstitution studies demonstrated that neutrophils contribute to the subsequent eosinophilia but are not responsible for the ability of IL-17A to promote type-2 cytokine responses. Transcriptional profiling of the lung on day 2 of N. brasiliensis infection revealed an increased Ifn{gamma} signature in the Il17a-KO mice confirmed by enhanced IFN{gamma} protein production. Depletion of early IFN{gamma} rescued type-2 immune responses in the Il17a-KO mice demonstrating that IL-17A-mediated suppression of IFN{gamma} promotes type-2 immunity. Notably, when IL-17A was blocked later in infection, the type-2 response increased. IL-17A regulation of type-2 immunity was lung-specific and infection with Trichuris muris, revealed that IL-17A promotes a type-2 immune response in the lung even when a parasite lifecycle is restricted to the intestine. Together our data reveal IL-17A as a major regulator of pulmonary type-2 immunity which supports the development of a protective type-2 immune response but subsequently limits the magnitude of that response.

immunology↗

bioRxiv2019

Trickle infection and immunity to Trichuris muris

The majority of experiments investigating the immune response to gastrointestinal helminth infection use a single bolus infection. However, in situ individuals are repeatedly infected with low doses. Therefore, to model natural infection, mice were repeatedly infected (trickle infection) with low doses of Trichuris muris. Trickle infection resulted in the slow acquisition of immunity reflected by a gradual increase in worm burden followed by a partial expulsion. Flow cytometry revealed that the CD4+ T cell response shifted from Th1 dominated to Th2 dominated, which coincided with an increase in Type 2 cytokines. The development of resistance following trickle infection was associated with increased worm expulsion effector mechanisms including goblet cell hyperplasia, Muc5ac production and increased epithelial cell turn over. Depletion of CD4+ T cells reversed resistance confirming their importance in protective immunity following trickle infection. In contrast, depletion of group 2 innate lymphoid cells did not alter protective immunity. T. muris trickle infection resulted in a dysbiotic mircrobiota which began to recover alpha diversity following the development of resistance.\n\nThese data support trickle infection as a robust and informative model for analysis of immunity to chronic intestinal helminth infection more akin to that observed under natural infection conditions and confirms the importance of CD4+ T cell adaptive immunity in host protection.\n\nAuthor SummaryInfection with parasitic worms (helminths) is a considerable cause of morbidity in humans. Understanding how we respond to infection is crucial to developing novel therapies. Laboratory models of helminth infection have been a valuable tool in understanding fundamental immune responses to infection. However, typically an individual mouse will be infected with a large, single-dose of the parasite. This is in contrast to the natural scenario in which individuals will receive frequent low level exposures. What is unknown is how repeated infection alters the development of immunity to infection. We have developed a laboratory model to tackle this question. We infected mice with the model helminth Trichuris muris on a weekly basis and assessed a range of responses in comparison with a more traditional infection system. We found striking differences in the dynamics of the infection, the host immune response, and in changes to host gut microbial populations. Our study shows how resistance to helminth infection can develop over time in response to repeat infection, and provides a model system that better reflects human immunity to this parasite.

immunology↗

bioRxiv2018

Exclusive dependence of IL-10Rα signalling on intestinal microbiota homeostasis and control of whipworm infection

The whipworm Trichuris trichiura is a soil-transmitted helminth that dwells in the epithelium of the caecum and proximal colon of their hosts causing the human disease, trichuriasis. Trichuriasis is characterized by colitis attributed to the inflammatory response elicited by the parasite while tunnelling through intestinal epithelial cells (IECs).\n\nThe IL-10 family of receptors, comprising combinations of subunits IL-10R, IL-10R{beta}, IL-22R and IL-28R, modulates intestinal inflammatory responses. Here we carefully dissected the role of these subunits in the resistance of mice to infection with T. muris, a mouse model of the human whipworm T. trichiura. Our findings demonstrate that whilst IL-22R and IL-28R are dispensable in the host response to whipworms, IL-10 signalling through IL-10R and IL-10R{beta} is essential to control caecal pathology, worm expulsion and survival during T. muris infections. We show that deficiency of IL-10, IL-10R and IL-10R{beta} results in dysbiosis of the caecal microbiota characterised by expanded populations of opportunistic bacteria of the families Enterococcaceae and Enterobacteriaceae. Moreover, breakdown of the epithelial barrier after whipworm infection in IL-10, IL-10R and IL-10R{beta}-deficient mice, allows the translocation of these opportunistic pathogens or their excretory products to the liver causing organ failure and lethal disease. Importantly, bone marrow chimera experiments indicate that signalling through IL-10R and IL-10R{beta} in haematopoietic cells, but not IECs, is crucial to control worm expulsion and immunopathology. These findings are supported by worm expulsion upon infection of conditional mutant mice for the IL-10R on IECs. Our findings emphasize the pivotal role of systemic IL-10R signalling on immune cells in promoting microbiota homeostasis and maintaining the intestinal epithelial barrier, thus preventing immunopathology during whipworms infections.\n\nAuthor summaryThe human gut is home to millions of bacteria, collectively called the microbiota, and also to parasites that include whipworms. The interactions between gut cells, the microbiota and whipworms define conditions for balanced parasitism. Cells lining the gut host whipworms but also interact with gut immune cells to deploy measures that control or expel whipworms whilst maintaining a barrier to prevent microbial translocation. Whipworms affect the composition of the microbiota, which in turn impacts the condition of the gut lining and the way in which immune cells are activated. In order to avoid tissue damage and disease, these interactions are tightly regulated. Here we show that signalling through a member of the IL-10 receptor family, IL-10R, in gut immune cells is critical for regulating of these interactions. Lack of this receptor on gut immune cells results in persistence of whipworms in the gut accompanied by an uncontrolled inflammation that destroys the gut lining. This tissue damage is accompanied by the overgrowth of members of the microbiota that act as opportunistic pathogens. Furthermore, the destruction of the gut barrier allows these bacteria to reach the liver where they cause organ failure and fatal disease.

immunology↗