AsianScientist (Oct. 22, 2018) – Scientists have discovered a potential treatment for severe malaria and drug-resistant malaria. Their findings are published in PLOS Pathogens.
Malaria is a mosquito-borne parasite which affects over 216 million people worldwide. There is no vaccine for malaria and antimalarial drugs are losing their efficacy with drug resistance on the rise, especially in Africa and South-east Asia. In 2017 alone, there were 445,000 malaria-induced deaths globally. For decades, doctors and scientists have been baffled by why some people are more vulnerable to malaria than others.
In the present study, a research collaboration among scientists from Massachusetts Institute of Technology, Singapore-MIT Alliance for Research and Technology and Nanyang Technological University, Singapore (NTU) have found a method to boost natural killer (NK) cells’ response to malaria infection.
During the initial phase of an infection by the malaria parasite, NK cells seek out and destroy infected red blood cells. Due to human genetic variation, some people have more responsive NK cells, while others do not.
By analyzing responsive and non-responsive NK cells, the joint research team discovered the pathway used by NK cells to detect infected red blood cells. They observed that infected red blood cells first secrete small microvesicles from their surface—extremely tiny sacs containing biomolecules such as ribonucleic acid (RNA), which are genetic instructions for producing proteins.
These microvesicles are then detected by the pathogen recognition receptor MDA5 located inside NK cells. The role of these receptors is to identify bacteria and viruses, subsequently triggering the NK cells to attack and kill infected red blood cells. Having established that NK cells with higher levels of MDA5 respond better to a malaria infection, the scientists were able to improve non-responding NK cells by activating MDA5 artificially with a synthetic drug compound in their lab tests.
“Moving forward, the possibility of applying the same concept for other infectious diseases is boundless. We know that MDA5 is a sensor for infected red blood cells, so we can use synthetic drugs to improve MDA5 and enhance NK cell function against other infectious diseases such as dengue, TB or even cancer,” said Professor Peter Preiser, Chair of NTU’s School of Biological Sciences and a senior author of the paper.
The article can be found at: Ye et al. (2018) Microvesicles From Malaria-infected Red Blood Cells Activate Natural Killer Cells via Mda5 Pathway.
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Source: Nanyang Technological University; Photo: Shutterstock.
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