Table_1_Schistosoma mansoni coactivator associated arginine methyltransferase 1 (SmCARM1) effect on parasite reproduction.XLSX

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Schistosoma mansoni依靠多样化的机制以适应其多样的环境和宿主。表观遗传机制在基因表达调控中扮演核心角色，最终导致这些适应性变化。蛋白质精氨酸甲基转移酶（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。辅活化因子相关精氨酸甲基转移酶1（CARM1/PRMT4）是具有PRMT核心结构域的S. mansoni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公共数据集中的表达。通过RNA干扰评估了SmCARM1的功能。基因表达水平得到评估，并在体外、体内和离体条件下分析了表型变化。结果：单细胞RNA测序数据表明，SmPRMTs的表达在成虫或毛蚴的任何细胞群中均不富集，除了Smcarm1的表达在模糊细胞群中富集，Smprmt1在毛蚴的NDF+神经元和茎/生殖细胞中富集。Smprmt1还富集于成虫的S1和晚期雌性生殖细胞中。体外暴露于双链RNA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，但在毛蚴或成虫的表型中未观察到显著变化。在感染小鼠后，对Smcarm1敲低的毛蚴进行体内分析，发现从小鼠中恢复的虫体数量没有显著变化，然而检测到的卵数量显著减少。体外虫体表现出卵巢面积显著减少，细胞分化程度降低，蛋黄腺细胞组织紊乱，以及睾丸叶面积减少。虫体表皮出现虫瘤数量减少，寄生虫的腹吸盘出现受损的表皮和与寄生虫身体分离的点。讨论：本研究首次对SmCARM1进行了功能鉴定，揭示了其在S. mansoni生物学中的作用及其作为药物靶点的潜力。需要进一步研究以确定所报道的Smcarm1敲低效应是否为Smcarm1介导的参与DNA包装的组蛋白尾巴或其他非组蛋白蛋白甲基化的结果。