<i>In vitro</i>, <i>in vivo</i> and <i>in silico</i> rationale for the muscle loss due to therapeutic drugs used in the treatment of <i>Mycobacterium tuberculosis</i> infection

Tuberculosis globally affects millions of people every year and is responsible for high rates of mortality and morbidity in tropical countries like India. The treatment of tuberculosis involves using the first line of drugs especially Isoniazid, Pyrazinamide, Streptomycin, Ethambutol and Rifampicin for treatment under the DOTS (Directly Observed Treatment Shots) regime which can last up to minimum of six months. These drugs although widely used against <i>Mycobacterium tuberculosis</i> has given rise to multi drug resistant (MDR) tuberculosis strain. It has been observed widely that prolonged drug treatment for tuberculosis patient has rendered several side effects that include increasing muscle wasting and malnutrition. In our study, we have investigated the role of these major tuberculosis drugs namely Rifampicin, Streptomycin, Isoniazid, Pyrazinamide, and Ethambutol on actin polymerization which are famously known to be a central player in the sarcomere region of the muscle in human body. For <i>in vitro</i> studies, we have used biophysical approaches such as 90° scattering assay (RLS), size exclusion chromatography (SEC), Dynamic light scattering (DLS), Circular dichroism spectroscopy (CD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), kinetic analysis to understand the time taken to break down effect of above mentioned drugs on actin disruption. I<i>n vivo</i> analysis was carried out on yeast Δ<i>end3</i> mutants which are rich in F-actin filaments in order to understand the effect of the aforementioned drugs in rendering the muscle wasting phenomenon in tuberculosis. Furthermore, we also carried out <i>in silico</i> analysis to understand the probable modes of binding of these drugs on actin filaments. Communicated by Ramaswamy H. Sarma

全球每年有数百万人感染结核病，在印度等热带国家，该病的死亡率与发病率均处于高位。结核病的临床治疗采用一线抗结核药物，包括异烟肼（Isoniazid）、吡嗪酰胺（Pyrazinamide）、链霉素（Streptomycin）、乙胺丁醇（Ethambutol）及利福平（Rifampicin），并遵循DOTS（直接面视下短程化疗，Directly Observed Treatment Shots）方案，治疗周期最短可达6个月。尽管上述药物被广泛用于对抗结核分枝杆菌（*Mycobacterium tuberculosis*），但已催生了耐多药结核病（multi drug resistant, MDR）菌株。临床广泛观察到，结核病患者接受长期药物治疗会引发多种不良反应，其中包括肌肉消耗与营养不良症状加剧。本研究针对5种主要抗结核药物：利福平、链霉素、异烟肼、吡嗪酰胺及乙胺丁醇，探究其对肌动蛋白聚合的调控作用。肌动蛋白是人体肌肉肌小节区域的核心功能蛋白。本研究的体外（in vitro）实验采用多种生物物理手段，包括90°散射测定（RLS）、尺寸排阻色谱（SEC）、动态光散射（DLS）、圆二色谱（CD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）及动力学分析，以明确上述药物引发肌动蛋白解聚所需的时间。体内（in vivo）实验以富含F-肌动蛋白丝的酵母Δend3突变体为模型，旨在探究上述药物对结核病相关肌肉消耗现象的影响。此外，本研究还开展了计算机模拟分析（in silico），以明确上述药物与肌动蛋白丝的潜在结合模式。由Ramaswamy H. Sarma转交。