N. Kishore Babu

By Sushma Singh and N. Kishore Babu

Sterol biosynthetic pathway is explored for its therapeutic potential for Visceral Leishmaniasis. In Leishmania, this pathway produces ergosterol which is absent in host and therefore is a promising strategy to combat proliferation of both extracellular and intracellular forms of the parasite with minimal host toxicity. The present chapter focuses on 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) enzyme which is the rate-limiting enzyme of the ergosterol biosynthesis. HMGR gene of L. donovani was biochemically and biophysically characterized for the first time. HMGR over expressing transgenic parasites were generated to evaluate its role in parasite growth and infection ability. A series of statins like atorvastatin, simvastatin and mevastatin were evaluated for its therapeutic efficacy and mode of action elucidated. Atorvastatin and mevastatin were found to be killing both the promastigote and amastigote forms of the parasite without exhibiting host cytotoxicity. Besides, non-statin class of molecules like resveratrol and glycyrrhizic acid were also analyzed for antileishmanial potential. Two antidepressants, ketanserin and mianserin were found to kill both L. donovani promastigotes and intracellular amastigotes with no apparent toxicity to the host cells. Since targeting of the sterol biosynthetic pathway enzymes may be useful therapeutically, the present work may have implications in treatment of Leishmaniasis.

Part of the book: Leishmaniases as Re-emerging Diseases