The effects of E. granulosus PSCs proteins on host immune cells were elucidated through Transcriptomic and Metabolomic analyses

BackgroundEchinococcus granulosus (E. granulosus), a causative agent of zoonotic diseases, is widely prevalent across most regions and primarily affects vital organs such as the liver and lungs. The parasite secretes immunomodulatory substances, and its protoscolex proteins (PSCs) have been identified as potential diagnostic antigens and vaccine candidates. Although transcriptomics and metabolomics approaches have been employed to investigate echinococcosis, the impact of PSCs on the functionality of host immune cells and the expression of immunomodulatory-related genes remains largely unexplored. MethodsIn this study, immunofluorescence analysis was employed to determine the binding of PSCs to lymphocytes. The CCK-8 assay was utilized to evaluate the impact of varying concentrations of PSCs on cell viability, while ELISA was performed to quantify the levels of cytokines such as IL-9 and IL-4. Furthermore, by integrating LC-MS/MS-based metabolomics and RNA-Seq-based transcriptomics technologies, a systematic analysis was conducted to investigate the metabolic reprogramming and differential gene expression in lymphocytes following PSCs treatment, thereby elucidating the molecular mechanisms underlying its immune regulatory effects. ResultsPSCs proteins inhibited lymphocyte proliferation in a concentration-dependent manner, promoted IL-9 secretion at low concentrations, enhanced IL-4 expression at medium concentrations, and continuously up-regulated TGF-{beta} with increasing concentrations. Transcriptomic analysis identified 1,840 differentially expressed genes (991 up-regulated and 849 down-regulated), and KEGG enrichment analysis highlighted metabolic pathways, including phenylalanine metabolism. Gene Ontology (GO) analysis revealed that the functions of these genes were primarily associated with immunometabolic reprogramming and regulation of the intestinal barrier. Metabonomic profiling detected 12 significantly altered metabolites (8 up-regulated and 4 down-regulated). These findings suggest that PSCs reshape the host immune microenvironment via a metabolic-gene network. This study systematically elucidates how PSCs regulate immune cell function and metabolic homeostasis through multiple targets, providing novel insights into the immune escape mechanisms of parasites. ConclusionPSCs can induce host immune metabolic reprogramming, characterized by the activation of pyrimidine metabolism and the inhibition of bilirubin-mediated oxidative stress, through concentration-dependent regulation of Th9 cytokines (IL-9, IL-4/TGF-{beta}) and suppression of the PI3K-Akt signaling pathway. This process remodels the immune tolerance microenvironment. The aim is to elucidate the molecular mechanisms underlying parasite escape via multi-dimensional immunometabolic regulation, thereby providing a novel direction for the targeted treatment of echinococcosis. Author summaryE. granulosus is a zoonotic disease that can cause space-occupying lesions in the liver, lung and other organs, seriously threaten human health and cause economic losses in animal husbandry. It evades immune attack through a variety of mechanisms.This study investigates the regulatory effects of E. granulosus PSCs on host immune cell function, with a focus on their concentration-dependent influence on Th9 cell differentiation and cytokine expression, including IL-9. Through integrative analyses of transcriptomics and metabolomics, we elucidate the molecular mechanisms underlying immunometabolic reprogramming induced by PSCs. Our findings demonstrate that at low concentrations, PSCs promote the secretion of IL-9 associated with Th9 cells, upregulate IL-4/TGF-{beta} signaling, activate pyrimidine metabolism (leading to thymidine accumulation), enhance bile secretion pathways, and increase bilirubin levels to suppress oxidative stress and T-cell function, thereby establishing an immune-tolerant microenvironment. This research provides the first comprehensive illustration of immune microenvironment remodeling mediated by PSCs via multi-omics network regulation, offering novel insights into the treatment of cystic echinococcosis and host-parasite interactions.