By studying flies genetically engineered to have muscle defects, scientists have taken a step toward explaining the mechanism and pathology of certain heart diseases in people. After making changes to the building blocks of the fruit fly version of a protein called troponin T, the researchers performed open-heart surgery and used microscopy to observe how the heart functioned differently than that of healthy fruit flies. Healthy fly hearts consist of a single tube that relaxes and expands to pump hemolymph – “fly blood.” However, the fly hearts with the defective troponin T did not relax and expand as well as healthy fly hearts, and also stayed contracted longer during the pumping phase. “This suggests that people with similar defects in this heart muscle protein may have hypercontracted hearts that aren’t able to relax, properly fill and pump as much blood through the body,” says Anthony Cammarato, Ph.D., assistant professor of cardiology at the Johns Hopkins University School of Medicine.
Fruit flies with defective troponin T were also unable to fly. When the researchers examined the muscles responsible for powering their wings, they realized that the muscles were torn to shreds from chronic hypercontraction. In addition to continuing work with troponin T, Cammarato says he plans to use fruit fly genetics to look for additional drug targets that could be used to develop treatments for inherited heart disease, like muscle proteins that promote relaxation
Johns Hopkins researchers at American Society of Cell Biology Annual Meeting
Special Interest Subgroup: Actin and Actin-Associated Proteins III
Tuesday, Dec. 18, 2012; Exhibit Halls A-C, 2 – 3:30 p.m.