Infection with Toxoplasma gondii induces inheritable epigenetic changes in mouse sperm. Infection with Toxoplasma gondii induces inheritable epigenetic changes in mouse sperm

In this study we sought to analyse if infection with the common human parasite Toxoplasma gondii aftered sperm epigenetics by sequecing small RNA from parasite infected and mock infected mice. Epigenetic changes in sperm is a well described process of inheritanece of paternal environmental experiences to their progeny. Using high throughput Illumina sequencing, we revealed differences between the sperm small RNA profiles of Toxoplasma-infected and control animals . We found 25.88% of small RNAs were differentially expressed after correcting for false discovery rate, of which 9.21% and 16.67% were up- and down-regulated, respectively. Further quantitative analysis revealed enriched small RNA load in our samples and biotypes composition analysis showed a majority tRNA population followed by miRNA and piRNA populations, while the rest contained various other small RNA transcripts.When we looked at miRNA changes between Toxoplasma-infected and control samples, we found that of the total miRNA mapped (585), 174 were differentially expressed in the Toxoplasma-infected group (FDR 2, respectively. Lastly, using gene enrichment analysis, we identified pathways regulated by small RNA’s that are differentially expressed and found that small RNA’s targeted distinct biological pathways. Overall design: Sequencing of sperm small RNA from mice injected with PBS control or Toxoplasma. 5 biological replicates in each group, each consisting of samples pooled from 2 mice.

本研究旨在探究常见人体寄生虫刚地弓形虫（Toxoplasma gondii）感染是否会影响小鼠精子表观遗传调控，通过对寄生虫感染组与模拟感染对照组小鼠的精子小RNA进行测序分析。精子表观遗传改变是将父代环境暴露信息传递给子代的经典遗传调控过程，该机制已有广泛研究报道。借助高通量Illumina测序技术，本研究分析发现弓形虫感染组与对照组小鼠的精子小RNA表达谱存在显著差异。经错误发现率（false discovery rate, FDR）校正后，共有25.88%的小RNA呈现差异表达，其中9.21%为表达上调，16.67%为表达下调。进一步定量分析显示本研究样本中的小RNA负载量显著富集；小RNA生物型组成分析结果表明，样本中占比最高的为转运RNA（transfer RNA, tRNA），其次为微RNA（microRNA, miRNA）与PIWI互作RNA（piwi-interacting RNA, piRNA），剩余部分则包含多种其他类型的小RNA转录本。在分析弓形虫感染组与对照组样本的miRNA表达差异时，本研究共比对到585个miRNA，其中174个在弓形虫感染组中呈现差异表达（原文此处FDR参数未完整标注）。最后，通过基因富集分析，本研究鉴定出差异表达小RNA所调控的信号通路，发现这些小RNA可靶向调控多条特异性生物学通路。实验整体设计：对注射PBS空白对照或弓形虫的小鼠精子小RNA进行测序。每组设置5个生物学重复，每个重复由2只小鼠的样本混合制备。