Team discovers genetic material in blood cells that may affect malaria parasites

August 15, 2012

Researchers at Duke University Medical Center may finally have discovered why people with sickle cell disease get milder cases of malaria than individuals who have normal red blood cells.

In a finding that has eluded scientists for years, Duke researchers discovered that genetic material in may help alter parasite activity via a novel mechanism that alters parasite gene regulation.

"One of the most interesting findings in our study is that the human microRNA (very small units of genetic material) found in sickle red cells directly participate in the of malaria parasites," said Dr. Jen-Tsan Chi, M.D., Ph.D., senior author and associate professor in the Duke Institute for and Policy and Department of and Microbiology. "These microRNAs enriched in the sickle red cells reduce the parasite's ability to propagate, so that certain people stay more protected."

MicroRNAs are small units of RNA, which come from DNA. MicroRNAs are only 20-25 nucleotides long and help to regulate .

The scientists also showed that when two different microRNAs were introduced at higher levels in normal red cells, the parasite growth also was decreased.

The findings appear in the journal .

"This finding should lead to greater understanding of the host-parasite interaction and parasite lifecycle, which may eventually develop into a new approach to therapy for malaria, which up to 500 million people develop each year worldwide," Chi said.

Every year about 1.5 to 3 million people die from the disease, most of them children, according to the (WHO). Between 1,000 and 2,000 cases occur in the United States.

"I think this work will expand our understanding of the interaction between the and its , given that this is a completely new mode of interaction between them, and will give us a far greater understanding of the parasite life cycle," said lead author Greg LaMonte, a scientist in the Chi laboratory.

The malaria parasites grow in the human red cells, cells that scientists thought lacked any genetic material. Many scientists had looked for the components in sickle cells that could help them resist the parasite, but the Duke researchers found one component by thinking outside of scientific norms.

The Duke team found microRNAs in the red and showed that their composition is dramatically different in the sickle red blood cells. Counter to what they expected, they showed that these differences directly contribute to the malaria resistance in sickle cell disease.

The scientists also conducted a different experiment that showed blocking these microRNAs (miR-451 and Let-7i is particular) in sickle cells reduced the ability of the cells to protect against malaria.

"If you block the miRNAs, the parasite grows two or three times as well," Chi said.

Another surprise in this investigation was the presence of a chimera, a fusion of human microRNA with the parasites' mRNAs.

"We never expected to find this," Chi said. "The fusion of human and parasite RNA represents a unique form of host-parasite interaction, and may reflect either a novel form of host-cell immunity or a mechanism by which the parasite is able to adapt to the host-cell environment."

Explore further: Sickle cell anemia as malaria defense

Related Stories

Sickle cell anemia as malaria defense

November 30, 2011
Sickle cell anemia causes pain, fatigue and delayed growth, all because of a lack of enough healthy red blood cells. And yet genetic mutations that cause it - recessive genes for the oxygen-carrying hemoglobin protein - have ...

Malaria parasite requires a single receptor to invade human red blood cells

November 9, 2011
Researchers have today revealed a key discovery in understanding how the most deadly species of malaria parasite, Plasmodium falciparum, invades human red blood cells. Using a technique developed at the Wellcome Trust Sanger ...

Mystery solved: How sickle hemoglobin protects against malaria

April 28, 2011
The latest issue of the journal Cell carries an article that is likely to help solve one of the long-standing mysteries of biomedicine. In a study that challenges currently held views, researchers at the Instituto Gulbenkian ...

Recommended for you

Large variety of microbial communities found to live along female reproductive tract

October 18, 2017
(Medical Xpress)—A large team of researchers from China (and one each from Norway and Denmark) has found that the female reproductive tract is host to a far richer microbial community than has been thought. In their paper ...

Study of what makes cells resistant to radiation could improve cancer treatments

October 18, 2017
A Johns Hopkins University biologist is part of a research team that has demonstrated a way to size up a cell's resistance to radiation, a step that could eventually help improve cancer treatments.

Inflammation trains the skin to heal faster

October 18, 2017
Scars may fade, but the skin remembers. New research from The Rockefeller University reveals that wounds or other harmful, inflammation-provoking experiences impart long-lasting memories to stem cells residing in the skin, ...

New approach helps rodents with spinal cord injury breathe on their own

October 17, 2017
One of the most severe consequences of spinal cord injury in the neck is losing the ability to control the diaphragm and breathe on one's own. Now, investigators show for the first time in laboratory models that two different ...

Pair of discoveries illuminate new paths to flu and anthrax treatments

October 17, 2017
Two recent studies led by biologists at the University of California San Diego have set the research groundwork for new avenues to treat influenza and anthrax poisoning.

New method to measure how drugs interact

October 17, 2017
Cancer, HIV and tuberculosis are among the many serious diseases that are frequently treated with combinations of three or more drugs, over months or even years. Developing the most effective therapies for such diseases requires ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.