Dr Gyanu Lamichhane from Johns Hopkins University visited GIBH

Dr Gyanu Lamichhane from Johns Hopkins University visited GIBH on the morning of 30th October 2012. He gave a presentation entitled: “Seeking new drugs to treat TB: Inhibiting biosynthesis of the peptidoglycan layer”. The seminar was hosted by Dr Zhang Tianyu from the center of infection and immunity, GIBH.

During his presentation, Dr Lamichhane highlighted his new findings on mycobacterial peptidoglycan layer. Mycobacterial peptidoglycan layer is cross-linked with both 4,3 and 3,3 linkages. Moreover, it was shown that 80% of the transpeptide linkages in the peptidoglycan of M. tuberculosis at stationary phase are of the non-classical 3,3 type. In Dr Lamichhane’s study, he reports the identification of a gene MT2594 that encodes an L,D-ranspeptidase for synthesis of non-classical 3,3 cross-linkages and shows that inactivation of the gene results in altered colony morphology, loss of virulence and increased susceptibility to amoxicillin-clavulanate during the chronic phase of infection. This suggests that 3,3 cross-linking is vital to the physiology of the peptidoglycan layer. Although a functional homolog exists, expression of MT2594 is dominant throughout the growth phases of M. tuberculosis. The 4,3 transpeitide linkages are targeted by one of the most widely used classes of antibacterial drugs in human clinical use today, namely β-lactams. Dr Lamichhane’s research shows that a combination of an L,D-transpeptidase and a β-lactamase inhibitors could effectively target persisters during chronic phase of TB. After the presentation, Dr Lamichhane had in depth discussion with the participants.

Dr Lamichhane has accomplished numerous achievements on the basic research of TB. He has published more than 20 papers on international top journals and he was awarded the “NIH Director’s New Inventor Award” in 2011.