Remote regulation of type 2 immunity by intestinal parasites

Adult Hymenolepis nana and its excretory-secretory products elicit mouse immune responses via tuft/IL-13 and FOXM1 signaling pathways

BACKGROUND

Hosts typically elicit diverse immune responses to the infection of various parasitic worms, with intestinal epithelial cells playing pivotal roles in detecting parasite invasion. Hymenolepis nana (H. nana) is a zoonotic parasitic worm that resides in the host's intestine. The contribution and underlying mechanisms of tuft cell-mediated immune reactions against H. nana remain unexplored.

METHODS

This study endeavors to examine the immune responses in the mouse intestine elicited by the adult H. nana and its excretory-secretory products (ESP). Ileal tissue alteration was detected using hematoxylin and eosin (H&E) staining, changes in the number of intestinal stem cells, goblet cells, tuft cells, and Paneth cells were detected by immunohistochemistry (IHC), immunofluorescence (IF), etc., and changes in the expression of type 2 cytokines and FOXM1 were detected by Western blotting (WB) or real-time quantitative polymerase chain reaction (RT-qPCR).

RESULTS

The presence of adult H. nana and its ESP enhanced the number of tuft cells and goblet cells while fostering the production of type 2 cytokines. Furthermore, the surge in Paneth cells and FOXM1 triggered by H. nana aids in maintaining intestinal stem cells homeostasis and proliferation. Notably, the FOXM1 inhibitor RCM-1 dampened intestinal stem cells differentiation and type 2 cytokines secretion, potentially impeding the host's capacity to eliminate H. nana.

CONCLUSIONS

The adult H. nana and its ESP stimulate the immune responses in mice through tuft/interleukin (IL)-13 and FOXM1 signaling pathways and promote the elimination of H. nana from the host through the differentiation of intestinal stem cells into tuft cells, goblet cells, and Paneth cells, as well as the activation of type 2 immune responses. Meanwhile, RCM-1 inhibits the immune responses to H. nana in mice, thus affecting the excretion of H. nana by host.

The role of helminths and their antigens in cancer therapy: insights from cell line models

BACKGROUND

Recent articles have explored the effect of worms on cancer cells. This review focused on various cell cultures employed to understand which cells are more commonly and less utilized.

METHODS

The present review analyzed studies published between 2013 and 2023 to obtain information about different cell cultures used in cancer studies involving helminths. Databases such as PubMed, Google Scholar, HINARI, and the Cochrane Library were searched.

RESULTS

This search yielded 130 records, but 97 papers were excluded because they were either irrelevant to the research topic (n = 72) or contradicted the research idea (n = 25).The remaining twenty-one articles focused on different types of worms, such as Echinococcus granulosus, Clonorchis sinensis, Opisthorchis felineus, Opisthorchis viverrini, Trichinella spiralis, Toxocara canis, and Heligmosomoides polygyrus.

CONCLUSION

Due to the presence of numerous antigens, parasites at different growth stages can impact various cells through unknown mechanisms. Given the high diversity of antigens and their effects, artificial intelligence can assist in predicting initial outcomes for future studies.

Chronic small intestinal helminth infection perturbs bile acid homeostasis and disrupts bile acid signaling in the murine small intestine

Intestinal helminths have evolved an abundance of immunomodulatory mechanisms to ensure long-lived infections in mammalian hosts. To manipulate mammalian immune responses helminths can directly produce immunomodulatory molecules, but helminth infection can also elicit functional changes in the intestinal microbiome which can impact immune functioning. Here we examined how bile acids (BA)s, a group of host-produced, microbiota-modified immunomodulatory metabolites, were altered in abundance and composition during a murine small intestinal helminth infection. We found that murine helminth infection resulted in consistently reduced concentrations of specific taurine-conjugated primary BAs (T-α-MCA and T-CDCA) in the small intestinal luminal contents of mice. BA transporters facilitate the uptake of BAs from the small intestinal lumen, allowing BAs to engage with nuclear BA receptors, and helminth infected mice showed reduced expression of genes encoding basal BA transporters in the small intestine. Finally, we report that there is reduced signaling through the nuclear BA receptor FXR in both the proximal small intestine and ileum of mice during small intestinal helminth infection. Together, our data reveal disruptions to BA homeostasis and signaling in the small intestine during helminth infection. As BAs are known to impact many aspects of mucosal physiology and immunity, examining the functional consequences of BA disruptions during helminth infection will be an important avenue for future research.

Trained immunity: A “new” weapon in the fight against infectious diseases

Innate immune cells can potentiate the response to reinfection through an innate form of immunological memory known as trained immunity. The potential of this fast-acting, nonspecific memory compared to traditional adaptive immunological memory in prophylaxis and therapy has been a topic of great interest in many fields, including infectious diseases. Amidst the rise of antimicrobial resistance and climate change—two major threats to global health—, harnessing the advantages of trained immunity compared to traditional forms of prophylaxis and therapy could be game-changing. Here, we present recent works bridging trained immunity and infectious disease that raise important discoveries, questions, concerns, and novel avenues for the modulation of trained immunity in practice. By exploring the progress in bacterial, viral, fungal, and parasitic diseases, we equally highlight future directions with a focus on particularly problematic and/or understudied pathogens.

The Role of Nuclear Factor Kappa B (NF-κB) in the Immune Response against Parasites

The immune system consists of various cells, organs, and processes that interact in a sophisticated manner to defend against pathogens. Upon initial exposure to an invader, nonspecific mechanisms are raised through the activation of macrophages, monocytes, basophils, mast cells, eosinophils, innate lymphoid cells, or natural killer cells. During the course of an infection, more specific responses develop (adaptive immune responses) whose hallmarks include the expansion of B and T cells that specifically recognize foreign antigens. Cell to cell communication takes place through physical interactions as well as through the release of mediators (cytokines, chemokines) that modify cell activity and control and regulate the immune response. One regulator of cell states is the transcription factor Nuclear Factor kappa B (NF-κB) which mediates responses to various stimuli and is involved in a variety of processes (cell cycle, development, apoptosis, carcinogenesis, innate and adaptive immune responses). It consists of two protein classes with NF-κB1 (p105/50) and NF-κB2 (p100/52) belonging to class I, and RelA (p65), RelB and c-Rel belonging to class II. The active transcription factor consists of a dimer, usually comprised of both class I and class II proteins conjugated to Inhibitor of κB (IκB). Through various stimuli, IκB is phosphorylated and detached, allowing dimer migration to the nucleus and binding of DNA. NF-κB is crucial in regulating the immune response and maintaining a balance between suppression, effective response, and immunopathologies. Parasites are a diverse group of organisms comprised of three major groups: protozoa, helminths, and ectoparasites. Each group induces distinct effector immune mechanisms and is susceptible to different types of immune responses (Th₁, Th₂, Th₁₇). This review describes the role of NF-κB and its activity during parasite infections and its contribution to inducing protective responses or immunopathologies.