Department of Biomolecular Sciences, Section of Biotechnology, University of Urbino Carlo Bo, via Arco d'Augusto 2, 61032, Fano, PU, Italy.
Centro di Referenza Nazionale Per le Leishmaniosi (C.Re.Na.L.), OIE Leishmania Reference Laboratory, Istituto Zooprofilattico Sperimentale della Sicilia A. Mirri, via G. Marinuzzi 3, 90129, Palermo, PA, Italy.
BMC Vet Res. 2022 Jun 27;18(1):247. doi: 10.1186/s12917-022-03359-5.
Leishmaniases are a group of anthropo-zoonotic parasitic diseases caused by a protozoan of the Leishmania genus, affecting both humans and other vertebrates, including dogs. L. infantum is responsible for the visceral and occasionally cutaneous form of the disease in humans and canine leishmaniasis. Previously, we have shown that L. infantum induces a mild but significant increase in endoplasmic reticulum (ER) stress expression markers to promote parasites survival in human and murine infected macrophages. Moreover, we demonstrated that the miRNA hsa-miR-346, induced by the UPR-activated transcription factor sXBP1, was significantly upregulated in human macrophages infected with different L. infantum strains. However, the ER stress response in infected dogs, which represent an important reservoir for Leishmania parasite, was described once recently, whereas the miR-346 expression was not reported before. Therefore, this study aimed to investigate these pathways in the canine macrophage-like cell line DH82 infected by Leishmania spp. and to evaluate the presence of cfa-miR-346 in plasma of non-infected and infected dogs. The DH82 cells were infected with L. infantum and L. braziliensis parasites and the expression of cfa-mir-346 and several ER stress markers was evaluated by quantitative PCR (qPCR) at different time points. Furthermore, the cfa-miR-346 was monitored in plasma collected from non-infected dogs (n = 11) and dogs naturally infected by L. infantum (n = 18).
The results in DH82 cells showed that cfa-mir-346 was induced at both 24 h and 48 h post-infection with all Leishmania strains but not with tunicamycin, accounting for a mechanism of induction independent from sXBP1, unlike what was previously observed in human cell lines. Moreover, the cfa-miR-346 expression analysis on plasma revealed a significant increase in infected dogs compared to non-infected dogs.
Here for the first time, we report the upregulation of cfa-miR-346 induced by Leishmania infection in canine macrophage-like cells and plasma samples of naturally infected dogs. According to our results, the cfa-miR-346 appears to be linked to infection, and understanding its role and identifying its target genes could contribute to elucidate the mechanisms underlying the host-pathogen interaction in leishmaniasis.
利什曼病是一组由原生动物利什曼原虫引起的人畜共患寄生虫病，影响人类和其他脊椎动物，包括狗。L. infantum 是导致人类内脏利什曼病和犬利什曼病的原因。此前，我们已经表明，L. infantum 诱导内质网（ER）应激表达标志物轻度但显著增加，以促进人类和鼠感染巨噬细胞中的寄生虫存活。此外，我们证明了由 UPR 激活转录因子 sXBP1 诱导的 miRNA hsa-miR-346 在感染不同 L. infantum 株的人巨噬细胞中显著上调。然而，感染狗的 ER 应激反应最近才被描述过，而 miR-346 的表达以前没有报道过。因此，本研究旨在研究感染利什曼原虫的犬巨噬细胞样细胞系 DH82 中的这些途径，并评估非感染和感染犬血浆中的 cfa-miR-346 。DH82 细胞用 L. infantum 和 L. braziliensis 寄生虫感染，并用定量 PCR（qPCR）在不同时间点评估 cfa-mir-346 和几种 ER 应激标志物的表达。此外，监测了来自非感染犬（n=11）和自然感染 L. infantum 的犬（n=18）的血浆中的 cfa-miR-346。
DH82 细胞的结果表明，cfa-mir-346 在感染所有利什曼菌株后 24 和 48 小时均被诱导，但在用衣霉素处理时没有被诱导，这与先前在人类细胞系中观察到的情况不同，表明诱导机制独立于 sXBP1。此外，对感染犬和非感染犬血浆中的 cfa-miR-346 表达分析显示，感染犬的表达显著增加。
这里首次报道了 cfa-miR-346 在犬巨噬细胞样细胞和自然感染犬的血浆样本中被利什曼原虫感染诱导。根据我们的结果，cfa-miR-346 似乎与感染有关，了解其作用并确定其靶基因可能有助于阐明利什曼病中宿主-病原体相互作用的机制。
