Design of RNA Polymerase Inhibitors as Therapeutics for Tuberculous Meningitis.

Abstract

Background: Tuberculosis is an infectious disease caused by Mycobacterium tuber-culosis. The current treatment protocols for pulmonary tuberculosis are quite effective, even though the treatment requires 3-6 months. The current treatment protocols for extrapulmonary tuberculosis are based on the same drugs that are used for pulmonary tuberculosis. However, the success rates are much lower for certain types of extrapulmonary tuberculosis, such as tubercu-lous meningitis. Tuberculous meningitis is one of the very few diseases attributable to bacteria that have a very high short-term mortality rate among diagnosed patients, even after treatment with antibiotics that are effective for pulmonary tuberculosis. For example, rifampicin is highly effective for the treatment of pulmonary tuberculosis, but its effectiveness for the treatment of tuberculous meningitis is much lower. The reason for the lower effectiveness of rifampicin against tuberculous meningitis is that it has low Blood-Brain Barrier (BBB) permeability, which results in lower concentrations of the drug at the required sites in the central nervous system.

Methods: In this work, ligands having improved BBB permeability and pharmacokinetic and pharmacodynamic properties, either similar to or better than that of rifampicin, have been designed. The BBB permeability of the designed molecules was assessed by using pkCSM, a machine-learning model. Pharmacokinetic properties, drug-likeness, and synthesizability were assessed by using SWISS-MODEL. The binding affinity of the designed drugs was assessed by using AutoDock Vina. A customized scoring function, StWN score, was used for a quantitative weighted assessment of all the properties of interest to rank the designed molecules.

Results: In this study, drug-like ligands have been designed that have been predicted to have high BBB permeability as well as high affinity for RNA polymerase β of Mycobacterium tuberculosis.

Conclusion: The best ligands generated by the tools employed were selected as potential drugs to address the current need for better options for the treatment of tuberculous meningitis.