NIH study identifies new targets for anti-malaria drugs

October 26, 2017

The deadliest malaria parasite needs two proteins to infect red blood cells and exit the cells after it multiplies, a finding that may provide researchers with potential new targets for drug development, according to researchers funded by the National Institutes of Health. Their study appears in the latest issue of Science.

Plasmodium falciparum, the species of parasite that causes the most malaria deaths worldwide, has developed drug-resistance in five countries in Southeast Asia.

In the current study, researchers sought to uncover the role of plasmepsins IX and X, two of the 10 types of plasmepsin proteins produced by P. falciparum for metabolic and other processes. They created malaria parasites that lacked plasmepsin IX or X under experimental conditions and compared them to those that had the two proteins.

The team found plasmepsin IX in rhoptries, specialized cell structures inside the parasite, which help it invade red blood cells. Parasites lacking plasmepsin IX had defective rhoptries. In addition, the team observed plasmepsin X in exonemes--small vesicles (balloon-like structures) that help malaria parasites exit infected cells. The team also discovered that plasmepsin X processes an important protein called SUB1. When deprived of plasmepsin X, the parasites couldn't process SUB1 and couldn't infect red blood cells or exit these cells after multiplying.

The researchers also identified three experimental malaria drugs that may work by targeting plasmepsin X. One drug, called CWHM-117, has already been tested in a mouse model of malaria. The new findings may help researchers modify CWHM-117 to make it more effective. Furthermore, parasites lacking the plasmepsins could potentially be used to screen candidate drugs to identify additional anti-malaria compounds.
-end-
The study was conducted in part by researchers from NIH's Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) and the Washington University School of Medicine in Saint Louis. Funding also was provided by the National Institute of Allergy and Infectious Diseases, the National Heart, Lung, and Blood Institute, and the National Institute of General Medical Sciences.

ARTICLE:

Nasamu AS, Glushakova S, Russo I, Vaupel B, Oksman A, Kim AS, Fremont DH, Tolia N, Beck JR, Meyers MJ, Niles JC, Zimmerberg J, and Goldberg DE. Plasmepsins IX and X are essential and druggable mediators of malaria parasite egress and invasion. Science DOI: 10.1126/science.aan1478 (2017)

About the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD):

NICHD conducts and supports research in the United States and throughout the world on fetal, infant and child development; maternal, child and family health; reproductive biology and population issues; and medical rehabilitation. For more information, visit https://www.nichd.nih.gov.

About the National Institutes of Health (NIH):

NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit http://www.nih.gov.

NIH/Eunice Kennedy Shriver National Institute of Child Health and Human Development

Related Malaria Articles from Brightsurf:

Clocking in with malaria parasites
Discovery of a malaria parasite's internal clock could lead to new treatment strategies.

Breakthrough in malaria research
An international scientific consortium led by the cell biologists Volker Heussler from the University of Bern and Oliver Billker from the UmeƄ University in Sweden has for the first time systematically investigated the genome of the malaria parasite Plasmodium throughout its life cycle in a large-scale experiment.

Scientists close in on malaria vaccine
Scientists have taken another big step forward towards developing a vaccine that's effective against the most severe forms of malaria.

New tool in fight against malaria
Modifying a class of molecules originally developed to treat the skin disease psoriasis could lead to a new malaria drug that is effective against malaria parasites resistant to currently available drugs.

Malaria expert warns of need for malaria drug to treat severe cases in US
The US each year sees more than 1,500 cases of malaria, and currently there is limited access to an intravenously administered (IV) drug needed for the more serious cases.

Monkey malaria breakthrough offers cure for relapsing malaria
A breakthrough in monkey malaria research by two University of Otago scientists could help scientists diagnose and treat a relapsing form of human malaria.

Getting to zero malaria cases in zanzibar
New research led by the Johns Hopkins Center for Communication Programs, Ifakara Health Institute and the Zanzibar Malaria Elimination Program suggests that a better understanding of human behavior at night -- when malaria mosquitoes are biting -- could be key to preventing lingering cases.

Widely used malaria treatment to prevent malaria in pregnant women
A global team of researchers, led by a research team at the Liverpool School of Tropical Medicine (LSTM), are calling for a review of drug-based strategies used to prevent malaria infections in pregnant women, in areas where there is widespread resistance to existing antimalarial medicines.

Protection against Malaria: A matter of balance
A balanced production of pro and anti-inflammatory cytokines at two years of age protects against clinical malaria in early childhood, according to a study led by ISGlobal, an institution supported by ''la Caixa'' Foundation.

The math of malaria
A new mathematical model for malaria shows how competition between parasite strains within a human host reduces the odds of drug resistance developing in a high-transmission setting.

Read More: Malaria News and Malaria Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.