How Malaria Turns Our RBCs Against Us

When red blood cells are infected with malaria parasites, subtle changes in their membrane structure cause them to deform and stick to blood vessel walls.

AsianScientist (May 8, 2015) – Scientists have discovered that infection with malaria parasites changes the shape of our red blood cells (RBCs), resulting in cells becoming stuck in brain blood vessels. This finding may provide an alternative way to combat malaria that could lead to new drug targets to help RBCs resist being transformed during infection.

Published in the Proceedings of the National Academy of Sciences, Professor Leann Tilley from the University of Melbourne and the Bio21 Institute said lifegiving RBCs are turned into potential killers upon invasion by malaria parasites.

A red blood cell travels 500 kilometers during its four-month lifespan. During each circulation of the body, the RBC squeezes through capillaries whose width is only about one quarter of RBC’s resting diameter and is exposed to high turbulence in the arteries. To survive this marathon, the RBC needs a very special membrane structure around the cell that is flexible enough to change shape but resilient enough to avoid damage.

“When an RBC becomes infected with the malaria parasite, the properties of the RBC change. The infected RBC becomes quite rigid and the cells stick to the walls of the host’s blood vessels. Accumulation in capillaries in organs such as the brain causes the severe symptoms associated with cerebral malaria,” Tilley said.

Cerebral malaria occurs mainly in children. It is a complication that occurs when parasites stick to blood vessels in the brain. It causes coma and once it is initiated, even with the best possible treatment, 10-20 percent of patients die.

Until now, it was not understood how the parasite that is growing inside the RBC makes its host cell so rigid. To better understand this, Tilley worked with a team of physicists and engineers, including Professor Zhang Sulin from Penn State University and colleagues from the Massachusetts Institute of Technology and Carnegie Mellon University.

“The engineers created a sophisticated mathematical model that describes how all the components work together,” she said.

The mathematical model explains how subtle changes to the molecular structure of the RBC membrane can change its ability to undergo deformation. It also explains how the rigidification of the host RBC membrane helps infected RBCs stick to blood vessel walls.

The team is hopeful that this new understanding will help design drugs that block the parasite-induced rearrangements of the RBC.

The article can be found at: Zhang et al. (2015) Multiple Stiffening Effects Of Nanoscale Knobs On Human Red Blood Cells Infected With Plasmodium falciparum Malaria Parasite.


Source: The University of Melbourne.
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