Jia Xin-Ming, Ma Zhi-Ping, Jia Yu, Gao Ping-Hui, Zhang Jun-Dong, Wang Yan, Xu Yong-Gang, Wang Lin, Cao Ying-Ying, Cao Yong-Bing, Zhang Li-Xin, Jiang Yuan-Ying
Department of Pharmacology, School of Pharmacy, Second Military Medical University, Shanghai 200433, China.
Biochem Biophys Res Commun. 2008 Sep 5;373(4):631-6. doi: 10.1016/j.bbrc.2008.06.093. Epub 2008 Jul 2.
Widespread and repeated use of azoles, particularly fluconazole, has led to the rapid development of azole resistance in Candida albicans. Overexpression of CDR1, CDR2, and CaMDR1 has been reported contributing to azole resistance in C. albicans. In this study, hyper-resistant C. albicans mutant, with the above three genes deleted, was obtained by exposure to fluconazole and fluphenezine for 28 passages. Thirty-five differentially expressed genes were identified in the hyper-resistant mutant by microarray analysis; among the 13 up-regulated genes, we successfully constructed the rta2 and ipf14030 null mutants in C. albicans strain with deletions of CDR1, CDR2 and CaMDR1. Using spot dilution assay, we demonstrated that the disruption of RTA2 increased the susceptibility of C. albicans to azoles while the disruption of IPF14030 did not influence the sensitivity of C. albicans to azoles. Meanwhile, we found that ectopic overexpression of RTA2 in C. albicans strain with deletions of CDR1, CDR2 and CaMDR1 conferred resistance to azoles. RTA2 expression was found elevated in clinical azole-resistant isolates of C. albicans. In conclusion, our findings suggest that RTA2 is involved in the development of azole resistance in C. albicans.
唑类药物，尤其是氟康唑的广泛且反复使用，已导致白色念珠菌对唑类药物的耐药性迅速发展。据报道，CDR1、CDR2和CaMDR1的过表达与白色念珠菌的唑类耐药性有关。在本研究中，通过将白色念珠菌暴露于氟康唑和氟奋乃静28代，获得了上述三个基因缺失的超耐药白色念珠菌突变体。通过微阵列分析在该超耐药突变体中鉴定出35个差异表达基因；在13个上调基因中，我们成功构建了CDR1、CDR2和CaMDR1缺失的白色念珠菌菌株中的rta2和ipf14030基因敲除突变体。使用斑点稀释试验，我们证明RTA2的缺失增加了白色念珠菌对唑类药物的敏感性，而IPF14030的缺失不影响白色念珠菌对唑类药物的敏感性。同时，我们发现CDR1、CDR2和CaMDR1缺失的白色念珠菌菌株中RTA2的异位过表达赋予了对唑类药物的抗性。在临床唑类耐药的白色念珠菌分离株中发现RTA2表达升高。总之，我们的研究结果表明RTA2参与了白色念珠菌唑类耐药性的形成。
