Study Identifies Aging-Associated Mitochondrial Circular RNAs

BUFFALO, NY — February 24, 2026 — A new #research paper was #published in Volume 18 of Aging-US on February 10, 2026, titled “Aging-associated mitochondrial circular RNAs.” Led by first author Hyejin Mun from the University of Oklahoma — with corresponding authors Je-Hyun Yoon from the University of Oklahoma and Young-Kook Kim from Chonnam National University Medical School — the study profiles mitochondrial circular RNAs in Peripheral Blood Mononuclear Cells (PBMCs) from young and old human cohorts and probes how mitochondrial circRNAs and the mitochondrial RNA-binding protein GRSF1 relate to mitochondrial metabolism and cellular senescence. Using total RNA sequencing of PBMCs from young and old donors and complementary cell-based experiments, the authors report that a large fraction of circular RNA junctions originates from the mitochondrial genome, with MT-RNR2 producing the most abundant circular junctions. They show that circMT-RNR2 levels are depleted in older cohorts and in replicative senescence of human fibroblasts, and that the mitochondria-localized RNA-binding protein GRSF1 interacts with both linear and circular MT-RNR2. Loss of GRSF1 reduced circMT-RNR2 levels, decreased mitochondrial TCA intermediates (fumarate and succinate), and accelerated cellular senescence and mitochondrial dysfunction — findings that link mitochondrial circRNAs to mitochondrial energetics and proliferative status in younger cells. “Taken together, our findings demonstrate the existence and possible function of circular MT-RNR2 during human aging and senescence, implicating its role in promoting the TCA cycle.” The authors note key limitations and outline next steps: clarifying the biogenesis mechanism of mitochondrial circular RNAs (including whether trans-splicing contributes), mapping direct interactions between mitochondrial transcripts and metabolic enzymes, and performing mechanistic studies (in vivo and in additional human cohorts) to test how circMT-RNR2 and GRSF1 influence mitochondrial energetics and organismal aging. These follow-ups will determine whether mitochondrial circular RNAs are actionable targets for modulating mitochondrial metabolism or delaying aspects of cellular aging. DOI - https://doi.org/10.18632/aging.206354 Corresponding authors - Je-Hyun Yoon - [email protected], and Young-Kook Kim - [email protected] Abstract video - https://www.youtube.com/watch?v=f8uZ6_tcOHw Sign up for free Altmetric alerts about this article - https://aging.altmetric.com/details/email_updates?id=10.18632%2Faging.206354 Subscribe for free publication alerts from Aging - https://www.aging-us.com/subscribe-to-toc-alerts Keywords - aging, circular RNA, MT-RNR2, GRSF1, TCA cycle To learn more about the journal, please visit https://www.Aging-US.com​​ and connect with us on social media at: Bluesky - https://bsky.app/profile/aging-us.bsky.social ResearchGate - https://www.researchgate.net/journal/Aging-1945-4589 X - https://twitter.com/AgingJrnl Facebook - https://www.facebook.com/AgingUS/ Instagram - https://www.instagram.com/agingjrnl/ LinkedIn - https://www.linkedin.com/company/aging/ Reddit - https://www.reddit.com/user/AgingUS/ Pinterest - https://www.pinterest.com/AgingUS/ YouTube - https://www.youtube.com/@Aging-US Spotify - https://open.spotify.com/show/1X4HQQgegjReaf6Mozn6Mc [email protected]