RESUMO
Some ABC transporters play a significant role in human health and illness because they confer multidrug resistance (MDR) through their overexpression. Compounds that inhibit the drug efflux mechanism can improve efficacy or reverse resistance. Of the eight described ABC transporter subfamilies, those proteins conferring MDR in humans are in subfamilies A, B, C, and G. In nematodes, transporters in subfamilies B and C are suggested to confer resistance to ivermectin. The Brugia malayi ABC transporter superfamily was examined to assess their potential to influence sensitivity to moxidectin. There was an increase in expression of ABC transporters in subfamilies A, B, C, and G following treatment. Co-administration of moxidectin with inhibitors of ABC transporter function did not enhance sensitivity to moxidectin in males; however, sensitivity was significantly enhanced in females and microfilariae. The work suggests that ABC transporters influence sensitivity to moxidectin and have a potential role in drug resistance.
Assuntos
Transportadores de Cassetes de Ligação de ATP/fisiologia , Antinematódeos/farmacologia , Brugia Malayi/efeitos dos fármacos , Resistência a Medicamentos/fisiologia , Transportadores de Cassetes de Ligação de ATP/genética , Animais , Antibióticos Antineoplásicos/farmacologia , Antinematódeos/antagonistas & inibidores , Brugia Malayi/metabolismo , Bloqueadores dos Canais de Cálcio/farmacologia , Daunorrubicina/farmacologia , Interações Medicamentosas , Feminino , Expressão Gênica , Macrolídeos/antagonistas & inibidores , Macrolídeos/farmacologia , Masculino , Microfilárias/efeitos dos fármacos , Microfilárias/metabolismo , Transcrição Gênica , Moduladores de Tubulina/farmacologia , Verapamil/farmacologia , Vimblastina/farmacologiaRESUMO
ABC systems are one of the largest described protein superfamilies. These systems have a domain organization that may contain 1 or more transmembrane domains (ABC_TM1F) and 1 or 2 ATP-binding domains (ABC_2). The functions (e.g., import, export and DNA repair) of these proteins distinguish the 3 classes of ABC systems. Mining and PCR-based cloning were used to identify 33 putative ABC systems from the Brugia malayi genome. There were 31 class 2 genes, commonly called ABC transporters, and 2 class 3 genes. The ABC transporters were divided into subfamilies. Three belonged to subfamily A, 16 to subfamily B, 5 to subfamily C, 1 to subfamily E and 3 to subfamilies F and G, respectively. None were placed in subfamilies D and H. Similar to other ABC systems, the ABC_2 domain of B. malayi genes was conserved and contained the Walker A and B motifs, the signature sequence/linker region and the switch region with the conserved histidine. The ABC_TM1F domain was less conserved. The relative abundance of ABC systems was quantified using real-time reverse transcription PCR and was significantly higher in female adults of B. malayi than in males and microfilaria, particularly those in subfamilies B and C, which are associated with drug resistance.
Assuntos
Transportadores de Cassetes de Ligação de ATP/química , Transportadores de Cassetes de Ligação de ATP/genética , Brugia Malayi/genética , Proteínas de Helminto/química , Proteínas de Helminto/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Motivos de Aminoácidos , Sequência de Aminoácidos , Animais , Brugia Malayi/classificação , Brugia Malayi/metabolismo , Feminino , Proteínas de Helminto/metabolismo , Masculino , Dados de Sequência Molecular , Filogenia , Estrutura Terciária de Proteína , Alinhamento de Sequência , Homologia de Sequência de AminoácidosRESUMO
The effect of ivermectin and moxidectin on the motility of Brugia malayi adults and microfilariae and on the fertility of B. malayi females was examined. Motility was reduced in adults after exposure to both drugs and worms were non-motile and dead within eight days. The motility of microfilariae was significantly reduced at all drug concentrations and ceased at concentrations of 2500 and 5000mug/mL. The motility of microfilariae released by females was reduced after exposure to both drugs, however ivermectin had a greater effect at concentrations between 170 and 5000mug/mL. Both drugs reduced the number of microfilariae released by females and within four days their release was inhibited. The presence of the bacterial endosymbiont Wolbachia was examined in adults and microfilariae after exposure to increasing concentrations of ivermectin and moxidectin. A decrease in wsp expression was correlated with increasing drug concentration.