Microbiome Alterations Driven by Trypanosoma cruzi Infection in Two Disjunctive Murine Models

Association between Capillaria hepatica infection-induced alterations in gut microbiota and estrogen expression in Brandt's voles (Lasiopodomys brandtii)

BACKGROUND

Capillaria hepatica, a zoonotic parasite, is present in the population of Brandt's voles (Lasiopodomys brandtii) and has been a central issue in ecological studies regarding its impact on host populations. Brandt's voles are known for their extremely high reproductive capacity, and the population explosion of Brandt's voles have occurred multiple times in the grasslands of Inner Mongolia over the past few decades. However, the mechanisms underlying the population dynamics of Brandt's voles, particularly in response to C. hepatica infection, remain poorly understood. Given the critical role of the gut microbiota in modulating hormones within the reproductive endocrine system, this study aims to explore how alterations in the gut microbiota influence the host's population dynamics in response to C. hepatica infection.

METHODS

Female Brandt's voles were inoculated with eggs of infected C. hepatica, and BALB/C mice were used as a control. At the end of the experimental period, cecal contents were collected for 16 S rRNA amplicon sequencing, and the expression levels of reproductive-related hormones were determined using enzyme-linked immunosorbent assay (ELISA).

RESULTS

C. hepatica infection leads to an increased diversity of gut microbiota in Brandt's voles, with significant changes in microbial composition. The relative abundance of Muribaculaceae and Eubacteriaceae increased significantly, while that of Rikenellaceae and Lachnospiraceae decreased significantly. The expression level of estradiol in the serum of infected Brandt's voles shows a slight decrease without statistical significance. However, the expression of equol is significantly higher in the infected group compared to the uninfected group, and the expression of enterolactone is significantly lower in the infected group than in the uninfected group.

CONCLUSIONS

This study demonstrates that infection with C. hepatica indirectly affect the abundance of specific gut microbiota in Brandt's voles, which are associated with reproductive hormones. This indirect effect on hormone expression can subsequently impact the reproductive function of the host. By investigating the changes in specific gut microbiota, this study sheds light on the mechanisms through which parasites regulate population fluctuations in Brandt's voles.

System-based insights into parasitological and clinical treatment failure in Chagas disease

Infectious disease treatment success requires symptom resolution (clinical treatment success), which often but not always involves pathogen clearance. Both of these treatment goals face disease-specific and general challenges. In this review, we summarize the current state of knowledge in mechanisms of clinical and parasitological treatment failure in the context of Chagas disease, a neglected tropical disease causing cardiac and gastrointestinal symptoms. Parasite drug resistance and persistence, drug pharmacokinetics and dynamics, as well as persistently altered host immune responses and tissue damage are the most common reasons for Chagas disease treatment failure. We discuss the therapeutics that failed before regulatory approval, limitations of current therapeutic options and new treatment strategies to overcome persistent parasites, inflammatory responses, and metabolic alterations. Large-scale omics analyses were critical in generating these insights and will continue to play a prominent role in addressing the challenges still facing Chagas disease drug treatment.

Parasite-microbiota interactions: a pathway to innovative interventions for Chagas disease, leishmaniasis, and ascariasis

Parasitic infections are a major global health challenge, driven in part by complex interactions between parasites, host microbiota, and immune responses. Recent advances in microbiome research highlight the critical role of microbiota in influencing disease outcomes and treatment effectiveness. This review examines how changes in the microbiota impact parasite transmission, disease progression, and responses to treatment, focusing on key parasitic diseases such as Chagas disease, leishmaniasis, and ascariasis. The microbiota can either exacerbate or mitigate disease severity, depending on its composition, providing critical insights for novel therapeutic strategies. Emerging approaches discussed include the use of targeted probiotics, prebiotics, and microbiota-modulating drugs to influence parasite dynamics and enhance conventional therapies. The review also explores the potential of integrating microbiota knowledge into vaccine design and immunotherapy, aiming to develop vaccines that elicit stronger immune responses and identify new therapeutic targets. A multidisciplinary approach is essential for translating these findings into effective clinical solutions, with future research focusing on validating microbiota-based interventions in clinical settings. In conclusion, the interaction between microbiota and parasitic infections presents a promising avenue for innovative therapies, with the potential to significantly improve global health outcomes.

The intersection of host in vivo metabolism and immune responses to infection with kinetoplastid and apicomplexan parasites

SUMMARYProtozoan parasite infection dramatically alters host metabolism, driven by immunological demand and parasite manipulation strategies. Immunometabolic checkpoints are often exploited by kinetoplastid and protozoan parasites to establish chronic infection, which can significantly impair host metabolic homeostasis. The recent growth of tools to analyze metabolism is expanding our understanding of these questions. Here, we review and contrast host metabolic alterations that occur in vivo during infection with Leishmania, trypanosomes, Toxoplasma, Plasmodium, and Cryptosporidium. Although genetically divergent, there are commonalities among these pathogens in terms of metabolic needs, induction of the type I immune responses required for clearance, and the potential for sustained host metabolic dysbiosis. Comparing these pathogens provides an opportunity to explore how transmission strategy, nutritional demand, and host cell and tissue tropism drive similarities and unique aspects in host response and infection outcome and to design new strategies to treat disease.

Small molecule mediators of host-T. cruzi-environment interactions in Chagas disease

Small molecules (less than 1,500 Da) include major biological signals that mediate host-pathogen-microbiome communication. They also include key intermediates of metabolism and critical cellular building blocks. Pathogens present with unique nutritional needs that restrict pathogen colonization or promote tissue damage. In parallel, parts of host metabolism are responsive to immune signaling and regulated by immune cascades. These interactions can trigger both adaptive and maladaptive metabolic changes in the host, with microbiome-derived signals also contributing to disease progression. In turn, targeting pathogen metabolic needs or maladaptive host metabolic changes is an important strategy to develop new treatments for infectious diseases. Trypanosoma cruzi is a single-celled eukaryotic pathogen and the causative agent of Chagas disease, a neglected tropical disease associated with cardiac and intestinal dysfunction. Here, we discuss the role of small molecules during T. cruzi infection in its vector and in the mammalian host. We integrate these findings to build a theoretical interpretation of how maladaptive metabolic changes drive Chagas disease and extrapolate on how these findings can guide drug development.

Localized cardiac small molecule trajectories and persistent chemical sequelae in experimental Chagas disease

Post-infectious conditions present major health burdens but remain poorly understood. In Chagas disease (CD), caused by Trypanosoma cruzi parasites, antiparasitic agents that successfully clear T. cruzi do not always improve clinical outcomes. In this study, we reveal differential small molecule trajectories between cardiac regions during chronic T. cruzi infection, matching with characteristic CD apical aneurysm sites. Incomplete, region-specific, cardiac small molecule restoration is observed in animals treated with the antiparasitic benznidazole. In contrast, superior restoration of the cardiac small molecule profile is observed for a combination treatment of reduced-dose benznidazole plus an immunotherapy, even with less parasite burden reduction. Overall, these results reveal molecular mechanisms of CD treatment based on simultaneous effects on the pathogen and on host small molecule responses, and expand our understanding of clinical treatment failure in CD. This link between infection and subsequent persistent small molecule perturbation broadens our understanding of infectious disease sequelae.