Data_Sheet_1_Schistosoma mansoni coactivator associated arginine methyltransferase 1 (SmCARM1) effect on parasite reproduction.PDF

IntroductionThe human blood fluke parasite Schistosoma mansoni relies on diverse mechanisms to adapt to its diverse environments and hosts. Epigenetic mechanisms play a central role in gene expression regulation, culminating in such adaptations. Protein arginine methyltransferases (PRMTs) promote posttranslational modifications, modulating the function of histones and non-histone targets. The coactivator-associated arginine methyltransferase 1 (CARM1/PRMT4) is one of the S. mansoni proteins with the PRMT core domain.MethodsWe carried out in silico analyses to verify the expression of SmPRMTs in public datasets from different infection stages, single-sex versus mixed-worms, and cell types. The SmCARM1 function was evaluated by RNA interference. Gene expression levels were assessed, and phenotypic alterations were analyzed in vitro, in vivo, and ex vivo.ResultsThe scRNAseq data showed that SmPRMTs expression is not enriched in any cell cluster in adult worms or schistosomula, except for Smcarm1 expression which is enriched in clusters of ambiguous cells and Smprmt1 in NDF+ neurons and stem/germinal cells from schistosomula. Smprmt1 is also enriched in S1 and late female germ cells from adult worms. After dsRNA exposure in vitro, we observed a Smcarm1 knockdown in schistosomula and adult worms, 83 and 69%, respectively. Smcarm1-knockdown resulted in reduced oviposition and no significant changes in the schistosomula or adult worm phenotypes. In vivo analysis after murine infection with Smcarm1 knocked-down schistosomula, showed no significant change in the number of worms recovered from mice, however, a significant reduction in the number of eggs recovered was detected. The ex vivo worms presented a significant decrease in the ovary area with a lower degree of cell differentiation, vitelline glands cell disorganization, and a decrease in the testicular lobe area. The worm tegument presented a lower number of tubercles, and the ventral sucker of the parasites presented a damaged tegument and points of detachment from the parasite body.DiscussionThis work brings the first functional characterization of SmCARM1 shedding light on its roles in S. mansoni biology and its potential as a drug target. Additional studies are necessary to investigate whether the reported effects of Smcarm1 knockdown are a consequence of the SmCARM1-mediated methylation of histone tails involved in DNA packaging or other non-histone proteins.

引言：人类血吸虫寄生虫曼氏血吸虫（Schistosoma mansoni）依赖多种机制以适应其多样化的环境和宿主。表观遗传机制在基因表达调控中扮演着核心角色，最终导致这些适应性变化。蛋白精氨酸甲基转移酶（Protein arginine methyltransferases，PRMTs）通过促进翻译后修饰，调节组蛋白和非组蛋白靶点的功能。辅活化蛋白相关精氨酸甲基转移酶1（Coactivator-associated arginine methyltransferase 1，CARM1/PRMT4）是具有PRMT核心结构域的曼氏血吸虫蛋白之一。方法：我们进行了计算机模拟分析，以验证SmPRMTs在不同感染阶段、单性别与混合虫体以及细胞类型中的表达。通过RNA干扰技术评估了SmCARM1的功能。基因表达水平在体外、体内和离体条件下进行了分析。结果：单细胞RNA测序（scRNAseq）数据显示，SmPRMTs的表达在成虫或毛蚴的任何细胞簇中均未富集，除Smcarm1在模糊细胞簇中富集外，Smprmt1在毛蚴的NDF+神经元和干细胞/原基细胞中富集。Smprmt1在成虫的S1和晚期雌性原基细胞中也富集。体外暴露于双链RNA（dsRNA）后，我们在毛蚴和成虫中观察到Smcarm1敲低，分别达到83%和69%。Smcarm1敲低导致产卵量减少，且在毛蚴或成虫表型中未观察到显著变化。在体内分析中，感染Smcarm1敲低毛蚴的小鼠中，从小鼠体内回收的虫体数量没有显著变化，然而，回收的虫卵数量显著减少。离体虫体表现出卵巢面积显著减小，细胞分化程度降低，蛋黄腺细胞排列紊乱，睾丸叶面积减小。虫体表皮出现痘疮数量减少，寄生虫的腹吸盘呈现受损表皮和与虫体分离的断裂点。讨论：本研究首次对SmCARM1的功能进行了描述，揭示了其在曼氏血吸虫生物学中的作用及其作为药物靶点的潜力。为进一步研究Smcarm1敲低的效果是否为Smcarm1介导的组蛋白尾甲基化（涉及DNA包装）或其他非组蛋白蛋白甲基化的结果，需要进一步的研究。