ATP Binding Cassette Transporter Mediates Both Heme and Pesticide Detoxification in Tick Midgut Cells.
ATP Binding Cassette Transporter Mediates Both Heme and Pesticide Detoxification in Tick Midgut Cells.
复制标题
ATP结合盒转运蛋白介导tick中肠细胞中的血红素和农药排毒。
DOI：
10.1371/journal.pone.0134779
复制
发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Oliveira PL
中科院分区：
文献类型：
--
作者：
Lara FA;Pohl PC;Gandara AC;Ferreira Jda S;Nascimento-Silva MC;Bechara GH;Sorgine MH;Almeida IC;Vaz Ida S Jr;Oliveira PL
在蜱中，血液的消化发生在细胞内，血红蛋白的蛋白水解消化发生在专门类型的溶酶体（消化囊泡）中，随后血红蛋白的血红素部分转移到专门的细胞器中，该细胞器积累大的血红素聚集体，称为血小体。在目前的工作中，我们研究了荧光金属卟啉，作为血红素类似物，和双甲脒，最常用的杀螨剂之一，以控制牛蜱侵扰，由扇头蜱（牛蜱）microplus中肠细胞的吸收。这两种化合物在体外被中肠细胞吸收并在血小体内积累。这两种分子的转运对环孢霉素A（CsA）敏感，CsA是一种众所周知的ATP结合盒（ABC）转运蛋白抑制剂。罗丹明123，一种荧光探针，也是公认的ABC底物，同样以CsA敏感的方式指向血小体。利用针对PgP-1型ABC转运蛋白保守结构域的抗体，我们能够将PgP-1免疫定位在消化囊泡膜上。两个R.对双甲脒具有抗性和敏感性的microplus菌株的研究表明，抗性菌株比敏感菌株更有效地解毒双甲脒和Sn-Pp IX，这一过程也对CsA敏感。与敏感菌株相比，含有ABC转运蛋白签名的转录物在双甲脒唑耐药菌株中的表达增加了2.5倍。RNAi诱导的ABC转运蛋白下调导致金属卟啉在消化泡中的积累，中断血红素运输到血小体。这一证据进一步证实了该转录本编码血红素转运蛋白。这是第一次报告血红素运输的吸血生物。虽然血红素体的主要生理功能是解毒血红素和减弱其毒性，我们认为，蜱使用这种杀螨剂解毒途径可能代表了一种新的分子机制，对农药的抗性。
In ticks, the digestion of blood occurs intracellularly and proteolytic digestion of hemoglobin takes place in a dedicated type of lysosome, the digest vesicle, followed by transfer of the heme moiety of hemoglobin to a specialized organelle that accumulates large heme aggregates, called hemosomes. In the present work, we studied the uptake of fluorescent metalloporphyrins, used as heme analogs, and amitraz, one of the most regularly used acaricides to control cattle tick infestations, by Rhipicephalus (Boophilus) microplus midgut cells. Both compounds were taken up by midgut cells in vitro and accumulated inside the hemosomes. Transport of both molecules was sensitive to cyclosporine A (CsA), a well-known inhibitor of ATP binding cassette (ABC) transporters. Rhodamine 123, a fluorescent probe that is also a recognized ABC substrate, was similarly directed to the hemosome in a CsA-sensitive manner. Using an antibody against conserved domain of PgP-1-type ABC transporter, we were able to immunolocalize PgP-1 in the digest vesicle membranes. Comparison between two R. microplus strains that were resistant and susceptible to amitraz revealed that the resistant strain detoxified both amitraz and Sn-Pp IX more efficiently than the susceptible strain, a process that was also sensitive to CsA. A transcript containing an ABC transporter signature exhibited 2.5-fold increased expression in the amitraz-resistant strain when compared with the susceptible strain. RNAi-induced down-regulation of this ABC transporter led to the accumulation of metalloporphyrin in the digestive vacuole, interrupting heme traffic to the hemosome. This evidence further confirms that this transcript codes for a heme transporter. This is the first report of heme transport in a blood-feeding organism. While the primary physiological function of the hemosome is to detoxify heme and attenuate its toxicity, we suggest that the use of this acaricide detoxification pathway by ticks may represent a new molecular mechanism of resistance to pesticides.