Behind every heartbeat is the sarcomere, a microscopic structure inside each heart cell that ignites the contraction. Now, researchers have found a protein called BAG3 may be responsible for sarcomere renewal — an indication that restoring the protein levels could repair the heart and inform future heart failure treatments, according to research published May 19 in Nature Communications.
The study, led by researchers from Loyola University Chicago, found that the protein binds to the sarcomere and ignites a process where tired, worn out proteins are guided out to be degraded by the cell. They found heart failure patients have a loss of sarcomere-anchored BAG3, which led to a build-up of worn-out components. Additionally, patients with the lowest levels of the protein were found to have the weakest cells.
As part of the research, the team induced heart failure in mice and waited two months before delivering BAG3 gene therapy, which was found to renew the sarcomere and its ability to contract at normal levels.
"We've known for almost half a century that the capacity of the sarcomere to generate force is significantly reduced in heart failure patients," Thomas Martin, lead study author and graduate student at Loyola, said in a news release sent to Becker's. "However, our research shows the importance of BAG3 and sarcomere protein renewal in disease and this may be an approach to strengthen the weakened heart."