University of Virginia Health System

October 6, 2004
Contact: Bob Beard
(434) 982-4490

CAT DISEASE GENE ONE KEY TO HEALTHY BLOOD IN HUMANS, U.Va. STUDY SUGGESTS

A gene linked to feline leukemia virus, a fatal cat disease, plays a role in human blood health, according to a study in the journal Cell by researchers at the University of Virginia Health System, in collaboration with researchers at the University of Washington, the University of Utah and Rockefeller University.

Red blood cells have a unique requirement for heme, the deep red, iron-containing component of hemoglobin to which oxygen binds. Without heme, mammals die.

Heme is also important for iron equilibrium and absorption in the body. However, heme can also be damaging to cells, which means it must be tightly regulated.  Cats infected with the “C” form of feline leukemia virus have a severe deficiency of oxygen-transporting red blood cells similar to a human disease called Pure Red Cell Aplasia. 

The group found that the human feline leukemia virus-C receptor, or FLVCR, a protein also found in the human body, acts as an "overflow valve," exporting excess heme from red blood-forming cells. The result suggests the gene protects developing red blood cells from heme toxicity.   The finding marks the discovery of the first heme transporter in mammals, providing another mechanism for control of heme in the body.

“This finding opens up an exciting new field of research into the mechanism that controls the movement of heme in and out of cells,” said study co-author Dr. Carl Berg, an expert in liver diseases and associate professor of internal medicine at U.Va. “One day, it may be possible to manipulate a protein to enhance iron absorption in the intestines providing treatment for iron deficiency, in the Third World for example. The protein can also be manipulated to minimize iron absorption in the liver, where too much iron can be harmful.”

“Some scientists believed that heme moved passively across cell membranes, but this research shows that transport proteins are required to regulate heme. We think this finding has broader implications in other diseases, such as iron overload” said Dr. Mark Worthington, a gastroenterologist and associate professor of internal medicine at U.Va. “This study also shows how effectively two independent academic institutions on different coasts, U. Va. and Washington, can collaborate on a new research finding that can be vital to blood health.”  

The study, titled “Identification of a Human Heme Exporter that Is Essentialfor Erythropoiesis,” is published in the Sept. 17 issue of Cell and can be found online at www.cell.com.

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