背景:在地中海盆地,已经确定了三种利什曼原虫:婴儿乳杆菌,L.Major和L.tropica,引起人畜共患内脏利什曼病(VL),人畜共患皮肤利什曼病(CL)和人证CL,分别。尽管动物模型和基因组/转录组学研究提供了重要的见解,调节VL和CL发展的致病因素仍然知之甚少。这项工作旨在鉴定感染了婴儿乳球菌的细胞共享的宿主转录特征,L.少校,和L.热带,以及由导致VL的寄生虫引起的特定转录特征(即,L.婴儿)和参与CL的寄生虫(即,L.少校,L.热带)。
结果:U937细胞分化成巨噬细胞样细胞,L.major和L.tropica为24h和48h,提取总RNA。RNA测序,在IlluminaNovaSeq6000平台上进行,用于在两个时间点评估感染细胞相对于未感染细胞的转录特征。EdgeR包用于鉴定差异表达的基因(倍数变化>2和FDR调整的p值<0.05)。然后,功能富集分析用于鉴定这些基因所涉及的富集的本体论术语。在感染后24小时,在所有感染条件中共有463个失调基因的共同特征被认识到,而在感染后48小时,共同特征减少到120个基因。除了常见的转录反应,我们证明了不同的上调功能途径表征婴儿乳球菌感染细胞,如VEGFA-VEGFR2和NFE2L2相关通路,表明血管重塑和氧化应激的减少是内脏化的潜在重要因素。
结论:确定寄生虫引起VL或CL的途径可能会导致利什曼病的新治疗策略,将经典的抗利什曼原虫化合物与宿主导向疗法相结合。
BACKGROUND: In the Mediterranean basin, three Leishmania species have been identified: L. infantum, L. major and L. tropica, causing zoonotic visceral leishmaniasis (VL), zoonotic cutaneous leishmaniasis (CL) and anthroponotic CL, respectively. Despite animal models and genomic/transcriptomic studies provided important insights, the pathogenic determinants modulating the development of VL and CL are still poorly understood. This work aimed to identify host transcriptional signatures shared by cells infected with L. infantum, L. major, and L. tropica, as well as specific transcriptional signatures elicited by parasites causing VL (i.e., L. infantum) and parasites involved in CL (i.e., L. major, L. tropica).
RESULTS: U937 cells differentiated into macrophage-like cells were infected with L. infantum, L. major and L. tropica for 24h and 48h, and total RNA was extracted. RNA sequencing, performed on an Illumina NovaSeq 6000 platform, was used to evaluate the transcriptional signatures of infected cells with respect to non-infected cells at both time points. The EdgeR package was used to identify differentially expressed genes (fold change > 2 and FDR-adjusted p-values < 0.05). Then, functional enrichment analysis was employed to identify the enriched ontology terms in which these genes are involved. At 24h post-infection, a common signature of 463 dysregulated genes shared among all infection conditions was recognized, while at 48h post-infection the common signature was reduced to 120 genes. Aside from a common transcriptional response, we evidenced different upregulated functional pathways characterizing L. infantum-infected cells, such as VEGFA-VEGFR2 and NFE2L2-related pathways, indicating vascular remodeling and reduction of oxidative stress as potentially important factors for visceralization.
CONCLUSIONS: The identification of pathways elicited by parasites causing VL or CL could lead to new therapeutic strategies for leishmaniasis, combining the canonical anti-leishmania compounds with host-directed therapy.