News Feature | March 18, 2014

MicroRNA Implicated In Heart Failure Can Be Blocked, Researchers Say

By Estel Grace Masangkay

A team of cardiovascular researchers have identified a microRNA which plays a crucial role in the onset and progression of heart failure. The researchers’ findings were published online in the journal Nature.

Researchers from the Cardiovascular Research Center at Icahn School of Medicine at Mount Sinai, Sanford-Burnham Medical Research Institute (Sanford-Burnham), and the University of California, San Diego showed how the newly discovered microRNA called miR-25 can be blocked to stop the chronic and fatal heart condition.

Mark Mercola, professor in the Development, Aging, and Regeneration Program at Sanford-Burnham and professor of bioengineering at UC San Diego Jacobs School of Engineering, and also a senior co-author in the study, said “Before the availability of high-throughput functional screening, our chance of teasing apart complex biological processes involved in disease progression like heart failure was like finding a needle in a haystack. The results of this study validate our approach to identifying microRNAs as potential therapeutic targets with significant clinical value.”

miR-25 blocks a gene called SERCA2a which regulates incoming and outgoing flow of calcium in the heart muscle cells. Decreased SERCA2a activity is a primary cause of poor heart contraction and enlargement of heart muscles leading to cardiac failure. The researchers used a screening system to discover how miR-25 delayed proper calcium uptake in patients suffering from heart failure.

Icahn School of Medicine researchers showed that by injecting a small piece of RNA, effects of miR-25 were inhibited leading to a dramatic stop to heart-failure progression in test mice. Inhibiting miR-25 also improved cardiac function and survival in the test subjects. Co-senior author Roger Hajjar said, “Currently, heart-failure medications do not effectively address the underlying mechanisms that weaken contractile function and lead to the enlargement of heart-muscle cells. Our study provides us with the key evidence we need to begin developing miR-25 as an important new therapeutic target, while adding our successful technique to block this microRNA to our growing arsenal of promising heart-failure therapies that we will further develop and test in future clinical trials.”

Almost six million people in the U.S. alone are afflicted with heart failure. The chronic condition is a leading cause of hospitalization in elderly patients. Various medications are used to provide temporary relief of heart failure’s debilitating symptoms but do not improve cardiac function or arrest disease progression.