Institute of Preventive Veterinary Medicine, Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, College of Animal Sciences, Zhejiang University, Hangzhou, 310058, People's Republic of China.
Shenzhen Entry-exit Inspection and Quarantine Bureau, Shenzhen, Guangdong, 518045, People's Republic of China.
Parasit Vectors. 2020 Jan 29;13(1):40. doi: 10.1186/s13071-020-3911-z.
Haemonchus contortus, a blood-feeding parasite, is constantly surrounded by large quantities of heme released from the catabolism of host red blood cells. To cope with the toxicity of free heme, H. contortus needs to uptake and detoxify the heme, a process believed to be paramount for parasite survival.
A heme-responsive gene Hc-hrg-2 was identified which is the homologue of Ce-hrg-2. The transcriptional levels in all developmental stages and heme-responsive ability of Hc-hrg-2 were analyzed by qRT-PCR. Immunofluorescence analysis and cell transfections were performed to analyze the expression pattern of Hc-HGR-2. Statistical analyses were performed with GraghPad Prism 6.0 using Student's t-test.
To investigate the heme homeostasis of H. contortus, we first identified a heme-responsive gene Hc-hrg-2, a homolog of Ce-hrg-2 that is involved in heme transport in the hypodermis of Caenorhabditis elegans. Using qRT-PCR, we showed that Hc-hrg-2 mRNA was expressed throughout all life-cycle stages of H. contortus with the highest level in the third-stage larvae (L3s). Notably, transcription of Hc-hrg-2 in the exsheathed L3s was significantly upregulated in the presence of high concentration of heme. We found that Hc-HRG-2 protein was mainly located in the hypodermal tissues of adult H. contortus in vivo and the endoplasmic reticulum in the transfected mammalian cells. Our in vitro assay demonstrated that Hc-HRG-2 is a heme-binding protein with glutathione S-transferase activity and heme had a significant effect on its enzymatic activity when a model substrate 1-chloro-2, 4-dinitrobenzene (CDNB) was used.
Hc-hrg-2 is a heme-responsive gene and engaged in heme homeostasis regulation in hypodermal tissues during the free-living stages of H. contortus.
捻转血矛线虫是一种吸血寄生虫，它一直被宿主红细胞分解产生的大量血红素所包围。为了应对游离血红素的毒性，捻转血矛线虫需要摄取和解毒血红素，这个过程被认为是寄生虫生存的关键。
本研究鉴定了一个血红素反应基因 Hc-hrg-2，它是 Ce-hrg-2 的同源物。通过 qRT-PCR 分析了 Hc-hrg-2 在所有发育阶段的转录水平和血红素反应能力。通过免疫荧光分析和细胞转染来分析 Hc-HGR-2 的表达模式。使用 GraphPad Prism 6.0 中的 Student's t-test 进行统计分析。
为了研究捻转血矛线虫的血红素稳态，我们首先鉴定了一个血红素反应基因 Hc-hrg-2，它是秀丽隐杆线虫表皮血红素转运中的 Ce-hrg-2 的同源物。通过 qRT-PCR，我们显示 Hc-hrg-2mRNA 在捻转血矛线虫的整个生命周期中都有表达，在第三期幼虫（L3s）中表达水平最高。值得注意的是，在高浓度血红素存在下，脱鞘 L3s 中的 Hc-hrg-2 转录显著上调。我们发现 Hc-HRG-2 蛋白主要位于体内成年捻转血矛线虫的表皮组织和转染的哺乳动物细胞的内质网中。我们的体外实验表明，Hc-HRG-2 是一种具有谷胱甘肽 S-转移酶活性的血红素结合蛋白，当使用模型底物 1-氯-2,4-二硝基苯（CDNB）时，血红素对其酶活性有显著影响。
Hc-hrg-2 是一个血红素反应基因，参与捻转血矛线虫自由生活阶段表皮组织的血红素稳态调节。
