Discovery of the Leishmania parasite's ability to block enzymes

Author(s): Jesslyn Thay, Source: Agência FAPESP , Date: 29 March 2021

A new discovery has led to further understanding of the how the parasites that cause leishmaniasis can cause widespread damage and deformities in those infected. Researchers from Fundação De Amparo À Pesquisa Do Estado De São Paulo published a study in the journal iScience about the discovery of the protozoa’s ability to block actions of defensive enzymes in human cells.

The mechanism involves Leishmania, macrophages and a virus that lives endosymbiotically in the parasite and is known as the Leishmania RNA virus (LRV), this itself was a recent discovery by the same team and project funded by the São Paulo Research Foundation in 2019.

The researchers found that the parasite inhibits activation of caspase-11 via LRV-induced autophagy. The caspase-mediated enzyme pathway results in programmed cell death and also assists the innate immune system.

This new discovery of the LRV ability to inhibit the caspase enzyme, helps scientists understand what hinders the human cells from blocking progression of the leishmaniasis disease. 

Mucocutaneous leishmaniasis is the most destructive type of the parasitic disease leaving those infected with facial ulcers and often incurable deformities. Visceral leishmaniasis is the deadliest form of the disease and can claim lives of those infected.

Leishmaniasis is a disease caused by parasites of the Leishmania type. It is spread by the bite of certain types of sandflies (genus Phlebotomus), and occurs across the tropics and sub-tropics of Africa, Asia, the Americas, and southern Europe.

Leishmaniasis is considered by the World Health Organization to one of the most important neglected tropical diseases, they estimate that about 4 to 12 million people are currently infected worldwide. yearly roughly 2 million new cases are diagnosed, an estimated 20,000 and 50,000 deaths due to the disease.

Renan V. H. de Carvalho Carvalho, currently a researcher at the Rockefeller University's Laboratory of Lymphocyte Dynamics in New York, said: "The iScience article solidifies our understanding that caspase-11 is extremely important to the pathogenesis of leishmaniasis"

"Everything we've shown about this system involving Leishmania, viruses and macrophages can have an impact on the fight against other diseases," continued Carvalho. "Hence the importance of basic science. Understanding biology serves as a foundation for the rapid future development of new therapies for diseases that already exist or could emerge in the future." 

To read the full article follow the link~:


Endosymbiotic RNA virus inhibits Leishmania-induced caspase-11 activation

de Carvalho, Renan V.H. et al.

iScience, Volume 24, Issue 1, 102004