Researchers at Cedars‑Sinai published a Science Translational Medicine paper describing TY1, a synthetic RNA‑based agent that augments TREX1 activity in macrophages to clear damaged DNA and promote cardiac tissue repair after ischemic injury. The team labeled TY1 the first “exomer” — a small‑RNA mimetic derived from therapeutic exosome cargo — and reported efficacy in animal models of myocardial infarction. TY1 was developed after sequencing RNA cargo from reparative heart progenitor cell exosomes; engineers designed a stabilized molecule that increases TREX1‑mediated exonuclease activity, reduces scar formation and improves functional recovery in preclinical studies. The investigators emphasized the drug’s design to mimic clinically validated RNA therapeutics. The work opens a potential new class of non‑cellular, RNA‑based regenerative therapies for ischemic and inflammatory tissue damage, though translation will require GLP toxicology, scalable manufacturing and human safety testing.