May 26, 2011
Study Of Bloodless Worms Yields Insight On Human Blood, Parasites & Iron Deficiency
Using a tiny bloodless worm, University of Maryland Associate Professor Iqbal Hamza and his team have discovered a large piece in the puzzle of how humans, and other organisms, safely move iron around in the body. The findings, published in the journal Cell, could lead to new methods for treating age-old scourges - parasitic worm infections, which affect more than a quarter of the world's population, and iron deficiency, the world's number one nutritional disorder.
Using C. elegans, a common microscopic worm that lives in dirt, Hamza and his team have identified a protein, called HRG-3 that transports heme -- the iron containing molecule that creates hemoglobin in blood -- from the mother's intestine to her developing embryos. According to Hamza and his coauthors this newly identified HRG-3-mediated pathway for transporting heme to developing oocytes also appears to be an excellent target for stopping the reproduction of hookworms and other parasites that feed on host red blood cell hemoglobin.
This new finding builds on a breakthrough Hamza's team made three years ago, when he and colleagues discovered HRG-1, a protein common to humans, which transports heme from the environment into the intestine of C. elegans.
"We've known the structure of hemoglobin for a really long time," said Hamza, "but we haven't been able to figure out how the heme gets into the globin, or exactly how humans and other living organisms move heme, which like iron is toxic, around and between cells." Such an understanding of how heme is transported in the body is critical to our understanding of how our bodies process and use iron, and thus of the development of more effective ways to deliver iron for absorption in the human intestine, he explained.
Hamza first started trying to uncover the secrets of heme transport in 2003. He and his team were studying the molecules and mechanisms involved in heme absorption in the intestine of C. elegans when, in 2008, they discovered that the protein HRG-1 escorts heme into the worm's gut, the first step of the intercellular journey.
"Now, in this current study we've looked at the next step in the transport process, which is how the worm moves heme from the intestine to other parts of its body" he said.
Hamza explained that for this step they chose to first study transport of heme between the mother