Title : The extended RD1 region protein EspG1: Its role in mycobacterial virulence and pathogenicity
Abstract:
Tuberculosis (TB), caused by Mycobacterium tuberculosis, is one of the deadliest diseases worldwide. The major challenge to the existing TB treatment is the emergence of Multidrug Resistant (MDR) M. tuberculosis which limits the success rate of treatment and therefore generating the need for introduction of new approaches and ways for TB treatment. Many genomic and functional studies have associated Region of Difference 1(RD1) locus of Mycobacterium tuberculosis with its pathogenicity. Recent studies have also revealed the role of flanking region of RD1, termed as extended RD1 locus, in its pathogenicity. The EspG1 is one of the extended RD1 region proteins and in this study an attempt has been made to understand the role of EspG1 from M. marinum (Mh3866) and its homologue from M. smegmatis (Ms3866) in virulence and pathogenicity. The C57Bl6 mice were immunized with Mh3866 and Ms3866 individually followed by infection with M. marinum and the resultant pathological features were assessed using histopathological analysis and Micro-CT analysis. The examination of visual pathological features i.e. presence of lesions on mice tail and its histopathological analysis suggests that Mh3866 immunization delayed the emergence of disease symptoms when compared to unimmunized mice whereas Ms3866 immunization did not show any difference when compared to unimmunized mice. The micro-CT analysis of mice tail vertebrae showed that the Mh3866 and Ms3866 immunization did not provide any protection to the host against bone erosion and bone damage upon infection with M. marinum. The immunization of Mh3866 protein is able to give protection in early phase of M. marinum infection but not in later phase. A good understanding of structural and functional characteristics of this protein will provide us its putative role in disease establishment progression and will also generate any new intervention approaches for better management of the human tuberculosis disease.
