CCH1或MID1基因缺失对白念珠菌药物耐受性及致病性的影响

Effect of CCH1 or MID1 gene disruption on drug tolerance and pathogenesis of Candida albicans

摘要:

CCH1和MID1基因编码的钙闸门是外源钙进入细胞内的重要通道，Ca2+作为细胞内重要的第2信使分子，其浓度的升高可激活相应的途径参与各种细胞反应过程。该研究将利用钙通路CCH1和MID1基因的单缺失菌株，并构建其相应的回补菌株，研究CCH1或MID1基因缺失后对白念珠菌药物耐受性和致病性的影响作用。通过药物平板敏感性试验和微量液基稀释法比较不同菌株对唑类药物敏感性的变化，进一步添加钙通道阻滞剂和钙离子螯合剂来分析钙离子浓度变化对药物作用的影响，结果发现CCH1或MID1基因的缺失明显对氟康唑和伊曲康唑表现出敏感性，且药物作用受到钙离子浓度变化的调节。最后建立小鼠感染模型分析不同菌株的毒力变化差异，确定CCH1或MID1基因的缺失显著减弱了白念珠菌的致病性。

Abstract:

The calcium gate encoded by CCH1 and MID1 genes is the main channel for external calcium absorption. As one of the important secondary messengers, the elevation of calcium concentration could activate some pathways to take part in various cell processes. In this study, we used CCH1 and MID1 mutant strains and also constructed their complementary strains to study the effect of drug tolerance and virulence of Candida albicans after CCH1 or MID1 deletion. By drug plate sensitivity assay and the broth microdilution method, we compared the changes between different strains. Moreover, we added calcium channel blocker and inhibitors to analyze the effect of calcium concentration on drug action. After the deletion of CCH1 or MID1 gene, the strain exhibited an obvious sensitivity to FLUC and ITRA, and the drug action was regulated by the calcium concentration. In a mouse model of intravenous infection, we found that attenuated virulence of cch1Δ/Δ or mid1Δ/Δ strain is specifically due to a loss of CCH1 or MID1 gene.