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Reversal of TET-mediated 5-hmC loss in hypoxic fibroblasts by ascorbic acid

Laboratory Investigation (2019) | Download Citation


Hypoxia resulting in hypoxia-inducible factor-1 alpha (HIF-1α) induction is known to drive scar formation during cutaneous wound healing, and may be responsible for excessive fibrosis inherent to hypertrophic scars and keloids. Because epigenetic pathways play an important role in regulation of fibrosing processes, we evaluated patient scars for DNA hydroxymethylation (5-hydroxymethylcytosine; 5-hmC) status and documented a significant decrease in scar fibroblasts. To test this finding in vitro, human fibroblasts were cultured with cobalt chloride (CoCl2), a known stimulant of HIF-1α. HIF-1α induced so resulted in loss of 5-hmC similar to that seen in naturally occurring scars and was associated with significant downregulation of one of the 5-hmC converting enzymes—ten–eleven translocation 3 (TET3)—as well as increased expression of phosphorylated focal adhesion kinase (p-FAK), which is important in wound contracture. These changes were partially reversed by exposure to ascorbic acid, a recognized epigenetic regulator potentially capable of minimizing excessive scar formation and promoting a more regenerative healing response. Our results provide a novel and translationally relevant mechanism whereby epigenetic regulation of scar formation may be manipulated at the level of fibroblast DNA hydroxymethylation.

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We are grateful for funding from the Harvard Stem Cell Institute that supported part of this initiative. Michael Wells provided valuable editorial assistance.

Author information


  1. Program in Dermatopathology, Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA

    • Yukun Liu
    • , Shuyun Xu
    • , Tingjian Zu
    • , Feng Li
    • , Shengbo Sang
    • , Cynthia Liu
    • , George F. Murphy
    •  & Christine G. Lian
  2. Division of Plastic Surgery, Department of Surgery, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA

    • Yukun Liu
    • , Yang An
    • , Bobin Mi
    •  & Dennis P. Orgill
  3. Department Plastic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China

    • Yukun Liu


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Conflict of interest

The authors declare that they have no conflict of interest.

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Correspondence to George F. Murphy or Christine G. Lian.

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