BOSTON, MA—Researchers at Brigham and Women's Hospital (BWH) have discovered a new gene that regulates hemoglobin synthesis during red blood cell formation. The findings advance the biomedical community's understanding and treatment of human anemias and mitochondrial disorders.
The study will be published online on November 7, 2012 in Nature.
The researchers used an unbiased zebrafish genetic screen to clone mitochondrial ATPase inhibitory factor-1 gene, or Atpif1. The gene allows animals—zebrafish, mice and humans for instance—to efficiently make hemoglobin. Hemoglobin is the protein in red blood cells responsible for transporting oxygen in the blood.
The researchers found that loss of Atpif1 causes severe anemia. Moreover, the researchers uncovered a broader mechanistic role for Atpif1—regulating the enzymatic activity of ferrochelatase, or Fech. Fech is the terminal enzyme in heme (a component of hemoglobin) synthesis.
"Our study has established a unique functional link between Atpif1-regulated mitochondrial pH, redox potential, and [2Fe-2S] cluster binding to Fech in modulating its heme synthesis," said Dhvanit Shah, PhD, BWH Division of Hematology, Department of Medicine, first study author.
The researchers were also able to produce data on the human version of Atpif1, noting its functional importance for normal red blood cell differentiation, and noting that a deficiency may contribute to human diseases, such as congenital sideroblastic anemias and other diseases related to dysfunctional mitochondria (the energy powerhouses of cells).
"Discovering the novel mechanism of Atpif1 as a regulator of heme synthesis advances the understanding of mitochondrial heme homeostasis and red blood cell development," said Barry Paw, MD, PhD, BWH Division of Hematology, Department of Medicine, senior study author.
Shah and Paw continue to identify new genes responsible for hematopoietic stem cell development and red cell differentiation. Their identification of new genes will elucidate the new mechanisms regulating hematopoiesis—the formation of blood cell components. Their work not only provides greater insight into human congenital anemias, but also new opportunities for improved therapies.
Anemia, a condition in which your blood has a lower than normal number of red blood cells or hemoglobin levels, can affect people of all ages. Women of childbearing age and older adults are at higher risk. Babies and children are also at risk for anemia due to nutritional iron deficiency or lead poisoning.
Shah and Paw also have faculty appointments at Harvard Medical School, Boston, MA.
This research was primarily supported by the Cooley's Anemia Foundation; March of Dimes Foundation; National Institute of Diabetes and Digestive and Kidney Diseases; and National Heart, Lung, and Blood Institute.
Brigham and Women's Hospital (BWH) is a 793-bed nonprofit teaching affiliate of Harvard Medical School and a founding member of Partners HealthCare. BWH has more than 3.5 million annual patient visits, is the largest birthing center in New England and employs nearly 15,000 people. The Brigham's medical preeminence dates back to 1832, and today that rich history in clinical care is coupled with its national leadership in patient care, quality improvement and patient safety initiatives, and its dedication to research, innovation, community engagement and educating and training the next generation of health care professionals. Through investigation and discovery conducted at its Biomedical Research Institute (BRI), BWH is an international leader in basic, clinical and translational research on human diseases, involving nearly 1,000 physician-investigators and renowned biomedical scientists and faculty supported by nearly $625 million in funding. BWH continually pushes the boundaries of medicine, including building on its legacy in organ transplantation by performing the first face transplants in the U.S. in 2011. BWH is also home to major landmark epidemiologic population studies, including the Nurses' and Physicians' Health Studies, OurGenes and the Women's Health Initiative. For more information and resources, please visit BWH's online newsroom.
Journal
Nature