Centro Internacional de Entrenamiento e Investigaciones Médicas (CIDEIM), Carrera 125 No. 19-225 Cali, Colombia.
J Antimicrob Chemother. 2014 Jan;69(1):139-49. doi: 10.1093/jac/dkt334. Epub 2013 Aug 24.
Treatment failure is multifactorial. Despite the importance of host cell drug transporters and metabolizing enzymes in the accumulation, distribution and metabolism of drugs targeting intracellular pathogens, their impact on the efficacy of antileishmanials is unknown. We examined the contribution of pharmacologically relevant determinants in human macrophages in the antimony-mediated killing of intracellular Leishmania panamensis and its relationship with the outcome of treatment with meglumine antimoniate.
Patients with cutaneous leishmaniasis who failed (n = 8) or responded (n =8) to treatment were recruited. Gene expression profiling of pharmacological determinants in primary macrophages was evaluated by quantitative RT-PCR and correlated to the drug-mediated intracellular parasite killing. Functional validation was conducted through short hairpin RNA gene knockdown.
Survival of L. panamensis after exposure to antimonials was significantly higher in macrophages from patients who failed treatment. Sixteen macrophage drug-response genes were modulated by infection and exposure to meglumine antimoniate. Correlation analyses of gene expression and intracellular parasite survival revealed the involvement of host cell metallothionein-2A and ABCB6 in the survival of Leishmania during exposure to antimonials. ABCB6 was functionally validated as a transporter of antimonial compounds localized in both the cell and phagolysosomal membranes of macrophages, revealing a novel mechanism of host cell-mediated regulation of intracellular drug exposure and parasite survival within phagocytes.
These results provide insight into host cell mechanisms regulating the intracellular exposure of Leishmania to antimonials and variations among individuals that impact parasite survival. Understanding of host cell determinants of intracellular pharmacokinetics/pharmacodynamics opens new avenues to improved drug efficacy for intracellular pathogens.
治疗失败是多因素的。尽管宿主细胞药物转运体和代谢酶在靶向细胞内病原体的药物的积累、分布和代谢中起着重要作用，但它们对抗利什曼原虫药物疗效的影响尚不清楚。我们研究了人巨噬细胞中与药物相关的决定因素在介导的内型利什曼原虫杀伤中的作用及其与葡甲胺锑治疗结果的关系。
招募了对治疗有反应（n=8）或失败（n=8）的皮肤利什曼病患者。通过定量 RT-PCR 评估了原代巨噬细胞中药物决定因素的基因表达谱，并将其与药物介导的寄生虫杀伤相关联。通过短发夹 RNA 基因敲低进行功能验证。
暴露于锑剂后，来自治疗失败患者的巨噬细胞中利什曼原虫的存活明显更高。16 个巨噬细胞药物反应基因受感染和葡甲胺锑暴露的调节。基因表达和寄生虫体内存活的相关性分析表明，宿主细胞金属硫蛋白-2A 和 ABCB6 参与了利什曼原虫在暴露于锑剂时的存活。ABCB6 作为一种位于巨噬细胞细胞和吞噬体膜中的锑化合物转运体得到了功能验证，揭示了宿主细胞调节细胞内药物暴露和吞噬细胞内寄生虫存活的新机制。
这些结果为宿主细胞调节利什曼原虫对锑剂的细胞内暴露的机制以及个体间影响寄生虫存活的差异提供了深入了解。对细胞内药代动力学/药效学的宿主细胞决定因素的理解为改善细胞内病原体的药物疗效开辟了新途径。
