Luciana Madeira da Silva and Stephen M. Beverley from the Washington University School of Medicine in St. Louis Missouri have discovered the Achilles’ heel of a deadly parasite. The parasite appears to be susceptible to a class of drugs that are already used to prevent organ rejection.
The parasite in question is called Leishmania, and is responsible for more misery than any other parasite on the planet, except for the one that causes malaria. As many as twelve million people worldwide are infected with Leishmania, with symptoms ranging from skin lesions and fever to death.
The Leishmania genome was found to contain three versions of a particular type of enzyme called a TOR kinase. Humans and other mammals have one version, mTOR. I wrote about this enzyme in conjunction with autism, but it is also essential for cell survival. Leishmania need all three mTOR genes in order to survive and infect humans.
In humans, the drug rapamycin is known to inhibit mTOR (which is why mTOR stands for ‘mammalian target of rapamycin’). Rapamycin is used as an immunosuppressant drug after organ transplantation. It’s also being tested as a cancer treatment. Now scientists plan to test it against Leishmania. If it doesn’t work, there are other drugs that might.
As Beverly optimistically states:
Given the numerous inhibitors already available, I think there's a pretty good chance that we'll be able to identify a compound that specifically inhibits one of Leishmania's TOR kinases.