The effects of iloprost treatment on molecular and neurocognitive responses to inhibited il-4r alpha function in a mouse model of trypanosomiasis
Year: 2025
Type: article
Abstract: The development of neurological disorders following trypanosome brain infection has been recognized for over a century. However, a comprehensive understanding of the neurocognitive and neuropathological changes associated with such infection and their progression remains a work in progress. Concurrently, there is ongoing research aimed at identifying innovative and effective trypanocidal compounds. Current therapeutic strategies are shifting toward the pharmacological activation of classical macrophage type-2 (M2) phenotype induced by IL-4 or IL-13 anti-inflammatory cytokines. Unlike proinflammatory M1 macrophages, which contribute to chronic inflammation and tissue damage, M2 macrophages exhibit anti-inflammatory properties, promoting healing and reducing pathological immune responses. Targeting M2 polarization has emerged as a promising strategy for treating inflammatory diseases, neurodegenerative disorders, and tissue injuries, by leveraging the body's innate mechanisms of immune modulation and repair. This study aims to investigate whether prostacyclin analogue (Iloprost) treatment against CNS Trypanosoma brucei infection would beneficially affect cognitive and anxiety-like behaviours in IL-4/IL-13-expressing mice, with the additional aim to understand whether trypanosome-induced pathological alterations in neurocognitive processes can be therapeutically reversed and to delineate the underpinned molecular and epigenetic mechanisms. A total of eighty male albino Swiss mice (8-10 weeks old) were used for the study, comprising sixteen mice for the pilot study and sixty-four mice for the main experiment. They were divided into two groups (n=32 per group); mice with pharmacologically inhibited interleukin 4 receptor (IL-4Rα┴) and their wild-type (WT) littermates. At day 4 (D4) post-infection with Trypanosoma brucei brucei, both WT and IL-4Rα┴ infected mice received repeated intraperitoneal injections of Iloprost (200μg/kg) for 3 days. Thereafter, the animals were assessed for locomotion, anxiety-like behaviour and reference memory using the open field test, elevated plus maze and novel object recognition task respectively. Blood samples were collected for parasitaemia and hemogram tests. The expression of target gene transcripts in the prefrontal cortices (PFC) and hippocampal (HPC) tissues was quantified using RT-PCR. Also, cytokine expression and methylation profiling were assessed using ELISA and EZ DNA methylation kits, respectively. IL-4R inhibition induced systemic inflammation in IL-4Rα┴ mice, whereas Iloprost treatment reversed this. Molecular analysis reveals downregulation of IL-4Rα genes in both the PFC and HPC of IL-4Rα┴ mice with IL-4 and IL-4Rα genes exhibiting decreased expression only in the HPC of IL-4Rα┴ infected mice, suggesting distinct regional responses to infection. Furthermore, IL-4Rα in synergy with Iloprost treatments not only reversed downregulated BDNF gene expression in the PFC but also attenuated the downregulation of TNF-α genes in both brain regions, while simultaneously suppressing the presence of trypanosome parasites in the CNS parenchyma by decreasing Pfr gene expression, NO, NF-κB and CXCL-10 levels in the PFC and HPC. The study further revealed hypomethylation within the promoter regions of IL-4, IL-4R, IL-13 and BDNF genes in both PFC and HPC of WT mice. In contrast, there was significant hypermethylation at xvi TNF-α, IL-4R, IL-4 and IL-13 promoter regions in the PFC and HPC of the Iloprost-treated infected groups for both WT and IL-4Rα┴ mice. Iloprost significantly (P<0.05) increased NF-kB levels but markedly decreased TNF-α in the HPC and PFC. This study revealed that Iloprost promotes angiogenesis and suppresses trypanosome-induced inflammation. IL-4 plays a role in cognitive learning, and prostacyclin is well known for its anti-inflammatory properties. Furthermore, Iloprost treatment enhanced both IL-4 and IL-13 signalling, and contributed to the reversal of anxiety-like behaviours and cognitive deficits induced by CNS trypanosome infection. The findings suggest that Iloprost plays a significant role in suppressing neuroinflammation in trypanosome-infected mice and that activation of IL-4Rα pathway via upregulation of BDNF and IL-4 signalling, may contribute to the neuroprotective effects of Iloprost against cognitive challenge.
Author: Olaolu, Oluwashola Samuel
Language: English
Subfield: Epidemiology
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W7220801762