Host Parasite Interactions Disease Modelling Molecular Mechanisms and Therapeutic Targeting

Abstract

Visceral leishmaniasis (VL) and its common cutaneous exacerbation known as Post Kala-azar Dermal Leishmaniasis (PKDL) cause a huge disease burden across the globe. In context to the early infection at the site of bite, the paucity exists in understanding the complex pathophysiology of Leishmania parasites while traversing the skin epithelia of the human host. In the current study firstly, we mimicked host-parasite interactions in host epithelium by establishing an in vitro cellular model involving co-culture of L. donovani with epithelial origin MDCK cells. Using various biochemical and cell biology-based techniques, we evaluate the host-pathogen interaction in the developed co-culture model system, which led to a novel mode of apoptosis called anoikis during co-infection. Further we studied the interplay of host factor fibronectin and parasite factor Gp63 (zinc metalloprotease) in-silico which played an important role in the anoikis phenomenon. Gp63 has a multifactorial role through the life cycle of parasite development and is known to bestow protection against complement-mediated lysis of parasites in the host system. Secondly, based on the available literature on zinc metalloprotease scaffolds and green chemistry approach, we designed and evaluated high affinity small molecule inhibitors. Upon treatment with these inhibitors, the various cellular and molecular assays clearly depicted detrimental effect on multiplication and infectivity of both promastigote and amastigote stages of parasite respectively. Thirdly, we also took peptide based therapeutic approach as an alternative measure to combat VL and PKDL. We developed non-coding genome derived tRNA peptide and evaluated leishmanicidal activity against promastigotes and intramacrophage amastigotes of Leishmania donovani. In summary, this work provides mechanistic insights leading to a better understanding of host-pathogen interaction. Moreover, it also lends weight for the development of novel pharmacological approaches against zinc metalloprotease that