Deakin scientists find new way to starve out malaria parasite

Deakin University scientists have discovered a new way to combat malaria, one of the world's top three infectious disease killers.

Senior researcher Professor Tania de Koning-Ward, from Deakin's Centre for Molecular and Medical Research, said her team had found a way to starve the malaria parasite, which in 2015 killed more than 400,000 people from an estimated 212 million cases.

"Malaria parasites live inside a red blood cell. They produce a group of proteins to change the permeability of the red blood cell, making it more porous, so they can absorb vital nutrients from plasma, and remove toxic waste products," Professor de Koning-Ward said.

"What we've shown is that if you genetically block one of these parasite proteins, you can effectively starve the parasite and it dies.

"Scientists have long been unsure about how the parasite makes the red blood cell permeable, so it's exciting to now have the evidence that shows this protein plays an important part in allowing the malaria parasite to take hold."

Professor de Koning-Ward said her team's finding was critical as the malaria parasites were becoming more resistant to current malaria medications, and half the world's population is estimated to be at risk of contracting the disease.

"Obviously we'd like to prevent malaria in first place, but unfortunately we don't yet have a vaccine that works really well," she said.

"We can also use preventative measures like mosquito nets, but even with these people are always going to get infected, so we need to be able to treat them with drugs.

"But along the line the parasites have become resistant to drugs. The World Health Organisation has recommended artemisinin combination therapies for people with malaria but now people in South East Asia are developing resistance to that.

"If that resistance spreads, we lose our last anti-malarial drugs. So we are really desperate to find new strategies to combat malaria.

"We're constantly searching for new drugs. We need to give people a combination of drugs that act on different pathways in the parasite so that we don't give the parasite a chance to thrive."

The scientists' findings were recently published in eLife, with a paper titled: 'Plasmodium parasites deploy RhopH2 into the host erythrocyte to obtain nutrients, grow and replicate'.

The work was published alongside two other papers from research groups in the UK and USA who used different approaches to also show this parasite protein, and another protein it interacts with, are critical for red blood cell permeability.

Lead author Dr Natalie Counihan, a research fellow at Deakin's School of Medicine, said the work was a crucial step in developing new drug targets.

"If you had a drug that blocked this protein then the parasite will die. Once you know what's responsible for something you can start designing drugs to fight that," Dr Counihan said.

"The fact that three research groups have independently come to the same conclusion is a real strength and means that we can now get on with designing drugs to block these pathways.

"To address the World Health Organisation's goal of control and elimination of malaria by 2030, effective new anti-malaria drugs are desperately required."

The Deakin-led research was completed with support from the Burnet Institute and Monash Institute of Pharmacological Sciences.

Article: Plasmodium falciparum parasites deploy RhopH2 into the host erythrocyte to obtain nutrients, grow and replicate, Natalie Counihan, Scott A Chisholm, Hayley E Bullen, Anubhav Srivastava, Paul R Sanders, Thorey K Jonsdottir, Greta E Weiss, Sreejoyee Ghosh, Brendan S Crabb, Darren J Creek, Paul R Gilson, Tania F de Koning-Ward, eLife, doi: 10.7554/eLife.23217, published 2 March 2017.