Palaniappan Balamurugan, Solomon Adline Princy, C David Raj
Quorum Sensing Laboratory, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur 613401, Tamil Nadu, India.
Central Animal Facility, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur 613401, Tamil Nadu, India.
Life Sci. 2021 May 15;273:119306. doi: 10.1016/j.lfs.2021.119306. Epub 2021 Mar 1.
The present study aims to target the quorum sensing (QS) accessory gene regulator A (AgrA) of Staphylococcus aureus to curtail bacterial virulence through drug repurposing approach.
In silico screening of chemical ligands that bind specifically to the S. aureus C-LytTR domain of AgrA (AgrA) was carried out. AgrA inhibition and downregulation of virulence genes linked to QS system of S. aureus were determined. Efficacy, dermal toxicity and drug tolerance induction were tested in Balb/C mice dermonecrosis model.
Bumetanide bound to the conserved amino acid Tyr-229 of AgrA and showed 70% AgrA inhibition at 0.1 μM. Highly significant reduction in the expression of representative virulence genes such as alpha-hemolysin (5 log-fold), phenol-soluble modulins (4 log-fold) and panton-valentine leukocidin (~3 log-fold) was noted in vitro. In vivo studies signified bumetanide to be highly effective in controlling the ulcer development and promoted wound healing. Also, the tested substance did not have dermal toxicity and no tolerance induction as well.
Targeting the QS regulators could be a possible alternative approach to curtail virulence in S. aureus. In addition, if the QS inhibitors are repurposed it could accelerate the drug development process and reduce the cost. The identified drug bumetanide inhibited AgrA and the results were in comparable to that of a known virulence inhibitor, diflunisal. The newly reported results of bumetanide in this study are expected to mark the drug's visibility for antibiotic adjunctive therapy and topical drug formulations for skin infections research.
本研究旨在通过药物重新利用的方法，靶向金黄色葡萄球菌的群体感应（QS）辅助基因调节因子A（AgrA），以降低细菌毒力。
对与AgrA的金黄色葡萄球菌C-LytTR结构域特异性结合的化学配体进行计算机筛选。测定AgrA抑制以及与金黄色葡萄球菌QS系统相关的毒力基因的下调情况。在Balb/C小鼠皮肤坏死模型中测试疗效、皮肤毒性和耐药性诱导情况。
布美他尼与AgrA保守氨基酸Tyr-229结合，在0.1μM时显示出70%的AgrA抑制率。在体外观察到代表性毒力基因如α-溶血素（约5个对数倍）、酚溶性调节蛋白（约4个对数倍）和杀白细胞素（约3个对数倍）的表达显著降低。体内研究表明布美他尼在控制溃疡发展和促进伤口愈合方面非常有效。此外，受试物质没有皮肤毒性，也没有耐药性诱导。
靶向QS调节因子可能是降低金黄色葡萄球菌毒力的一种可行替代方法。此外，如果重新利用QS抑制剂，可以加速药物开发过程并降低成本。已鉴定的药物布美他尼抑制AgrA，其结果与已知的毒力抑制剂双氟尼酸相当。本研究中布美他尼的新报道结果有望提高该药物在抗生素辅助治疗和皮肤感染研究局部药物制剂方面的知名度。
