Ticks and Tick-Borne Diseases ( IF 3.2 ) Pub Date : 2020-01-31 , DOI: 10.1016/j.ttbdis.2020.101402 Xin-Ru Wang 1 , Timothy J Kurtti 1 , Jonathan D Oliver 2 , Ulrike G Munderloh 1
Ticks are obligate hematophagous arthropods and must tolerate starvation during off‐host periods. Macroautophagy (hereafter autophagy) is a well-conserved self-eating mechanism of cell survival and is essential for recycling cellular contents during periods of starvation, stress, and injury in organisms. Although the genome sequence of Ixodes scapularis (Say) is available, the characteristics and functions of autophagy-related gene families remain largely unknown. To advance our understanding of autophagy in I. scapularis, we used comprehensive genomic approaches to identify Atg genes. Homologues of 14 Atg genes were identified, and their protein motif compositions were predicted. Phylogenetic analysis indicated that ATGs in I. scapularis were evolutionarily closely related to their homologues in Haemaphysalis longicornis and Rhipicephalus microplus ticks. Expression patterns of Atg genes differed across tick developmental stages. Immunofluorescence results by monodansylcadaverine (MDC) staining indicated that autophagy was activated after amino acid starvation treatments in I. scapularis embryo-derived cell lines ISE6 and IDE8. Subsequently, the expression of key Atg genes involved in autophagy pathway in both cell lines were examined. In ISE6 cells, the expression levels of three Atg genes (Atg4B, Atg6 and Atg8A) increased significantly after amino acid starvation; similarly, four Atg genes (Atg4A, Atg4B, Atg6 and Atg8B) were upregulated in IDE8 cells in response to starvation. In parallel, the MDC and lysotracker staining results indicated that autophagy was triggered after amino acid starvation treatments in R. microplus embryo-derived cell line BME26. Our observations showed that Atg family genes are highly conserved in ticks and function in autophagy pathway induced by amino acid starvation. These results also provide valuable insight for further autophagy-related research as a new strategy for blocking the transmission of tick-borne pathogens.
中文翻译:
肩x舌虫对氨基酸饥饿的响应与tick自噬相关基因的鉴定。
cks虫是专性的食血节肢动物,在寄主时期必须忍受饥饿。巨自噬(以下称自噬)是一种良好的自我生存的细胞存活机制,对于饥饿,压力和机体受伤期间的细胞内容物回收至关重要。尽管肩x突触螨的基因组序列是可用的,但自噬相关基因家族的特征和功能仍然未知。为了增进我们对肩cap鱼自噬的理解,我们使用了全面的基因组方法来鉴定Atg基因。鉴定了14个Atg基因的同源物,并预测了它们的蛋白基序组成。系统发育分析表明,ATGs在肩cap鱼在进化上与其在长血Ha和微小头R中的同源性密切相关。Atg基因的表达模式在tick的发育阶段有所不同。单丹酰尸胺(MDC)染色的免疫荧光结果表明,在肩鱼胚胎来源的细胞系ISE6和IDE8中进行氨基酸饥饿处理后,自噬被激活。随后,检查了两种细胞系中参与自噬途径的关键Atg基因的表达。在ISE6细胞,三个表达水平署理基因(Atg4B,ATG6和Atg8A)氨基酸饥饿后显着增加;类似地,四个署理基因(Atg4A,Atg4B,ATG6和Atg8B)在IDE8细胞响应于饥饿被上调。并行地,MDC和溶酶体示踪剂染色结果表明,自噬是在氨基酸饥饿处理后触发R. microplus胚胎衍生的细胞系BME26。我们的观察结果表明Atg家族基因在壁虱中高度保守,并在氨基酸饥饿诱导的自噬途径中起作用。这些结果也为进一步的自噬相关研究提供了宝贵的见识,作为阻止of传病原体传播的新策略。