Reprogramming Scars

After a heart attack, cardiac fibroblasts (shown) immediately patch up the damage to save the tissue. But, the scar they form is tough and non-contractile meaning the heart’s pumping function is compromised, which can ultimately result in its failure. To improve outcomes of patients after heart attacks, scientists are investigating in mice ways to reprogram the fibroblasts into muscle. The problem is, adult fibroblasts are particularly reluctant to change – in part, it seems, because of a transcription factor called Epas1 (stained red). But, a cocktail of RNA molecules that block Epas1 and promote muscle identity seems to do the trick. When scientists packaged this cocktail into membrane-bound droplets (called exosomes) and delivered them to the injured hearts of mice, the fibroblasts reprogrammed, scarring was reduced and heart function improved. If such an approach can be adapted for humans, it may help to maintain heart function and prolong life after a heart attack.

Written by Ruth Williams

Ruth Williams

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Ruth is a freelance science journalist based in the US. She's a regular correspondent for The Scientist, and her work has appeared in The Lancet, Nature, Scientific American Mind, BBC Focus and elsewhere. Twitter @rooph

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• Image from work by Hualing Sun and colleagues
• Mandel Center for Heart and Vascular Research, and the Duke Cardiovascular Research Center, Duke University Medical Center, Durham, NC, USA
• Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in Journal of Biological Chemistry, April 2023