Compounds with Potential Activity against Mycobacterium tuberculosis

Abstract

The high acquisition rate of drug resistance by necessitates the ongoing search for new drugs to be incorporated in the tuberculosis (TB) regimen. Compounds used for the treatment of other diseases have the potential to be repurposed for the treatment of TB. In this study, a high-throughput screening of compounds against thiol-deficient strains and subsequent validation with thiol-deficient strains revealed that and mutants had increased susceptibility to azaguanine (Aza) and sulfaguanidine (Su); and mutants had increased susceptibility to bacitracin (Ba); and, , and mutants had increased susceptibility to fusaric acid (Fu). Further analyses revealed that some of these compounds were able to modulate the levels of thiols and oxidative stress in This study reports the activities of Aza, Su, Fu, and Ba against and provides a rationale for further investigations.

Generation and characterization of thiol-deficient Mycobacterium tuberculosis mutants

“…In addition, in order to relate the role of ERG to MSH, a MSH-deficient mutant was generated through an in frame hygromycin marked deletion of mshA 8 ( Table 1 ). Intracellular 8 and extracellular 9 thiol levels of the generated mutants were measured by liquid chromatography tandem mass spectrometry (LC-MS).…”

“…In addition, it facilitates experimental optimizations since it is fast-growing (doubling time of ~3-4 h relatively to a doubling time of ~24 h for M.tb ) 14 , 15 , taking into account that the HTS required a series of optimizations. Few hits were obtained by the HTS 9 . Four hits were further expounded on M.tb , namely azaguanine (Aza), sulfaguanidine (Su), bacitracin (Ba) and fusaric acid (Fu).…”

“…Four hits were further expounded on M.tb , namely azaguanine (Aza), sulfaguanidine (Su), bacitracin (Ba) and fusaric acid (Fu). They were tested against thiol-deficient M.tb mutants by growth profiles analysis under the various treatments 9 . The growth inhibition of each compound on each strain was calculated from the growth curves raw data.…”

“…The growth inhibition of each compound on each strain was calculated from the growth curves raw data. To further understand the mechanism of action of these compounds in relation to thiols, the ability of these compounds to modulate the level of thiols (relative to the untreated controls) was investigated by LC-MS 9 . Since the general role of thiols is to protect cells against oxidative stress 16 , the ability of these compounds to generate oxidative stress (relative to the untreated controls) was also evaluated 9 .…”

“…To further understand the mechanism of action of these compounds in relation to thiols, the ability of these compounds to modulate the level of thiols (relative to the untreated controls) was investigated by LC-MS 9 . Since the general role of thiols is to protect cells against oxidative stress 16 , the ability of these compounds to generate oxidative stress (relative to the untreated controls) was also evaluated 9 . This was achieved by measuring the fluorescence intensity of the highly fluorescent 2',7'-dichlorofluorescein (DCF) 17 that resulted from the cleavage by oxidation of the acetate groups of the non-fluorescent 2′,7′-dichlorofluorescein diacetate (DCFDA).…”