Hematoma Resolution In Vivo Is Directed by Activating Transcription Factor 1

Anusha Seneviratne, Yumeng Han, Eunice Wong, Edward R H Walter, Lijun Jiang, Luke Cave, Nicholas J Long, David Carling, Justin C Mason, Dorian O Haskard, Joseph J Boyle

Research output: Contribution to journalArticlepeer-review


RATIONALE: The efficient resolution of tissue hemorrhage is an important homeostatic function. In human macrophages in vitro, heme activates an AMPK (AMP-activated protein kinase)/ATF1 (activating transcription factor-1) pathway that directs Mhem macrophages through coregulation of HO-1 (heme oxygenase-1; HMOX1) and lipid homeostasis genes.

OBJECTIVE: We asked whether this pathway had an in vivo role in mice.

METHODS AND RESULTS: Perifemoral hematomas were used as a model of hematoma resolution. In mouse bone marrow-derived macrophages, heme induced HO-1, lipid regulatory genes including LXR (lipid X receptor), the growth factor IGF1 (insulin-like growth factor-1), and the splenic red pulp macrophage gene Spic. This response was lost in bone marrow-derived macrophages from mice deficient in AMPK (Prkab1-/-) or ATF1 (Atf1-/-). In vivo, femoral hematomas resolved completely between days 8 and 9 in littermate control mice (n=12), but were still present at day 9 in mice deficient in either AMPK (Prkab1-/-) or ATF1 (Atf1-/-; n=6 each). Residual hematomas were accompanied by increased macrophage infiltration, inflammatory activation and oxidative stress. We also found that fluorescent lipids and a fluorescent iron-analog were trafficked to lipid-laden and iron-laden macrophages respectively. Moreover erythrocyte iron and lipid abnormally colocalized in the same macrophages in Atf1-/- mice. Therefore, iron-lipid separation was Atf1-dependent.

CONCLUSIONS: Taken together, these data demonstrate that both AMPK and ATF1 are required for normal hematoma resolution. Graphic Abstract: An online graphic abstract is available for this article.

Original languageEnglish
Pages (from-to)928-944
Number of pages17
JournalCirculation Research
Issue number7
Publication statusPublished - 11 Sept 2020
Externally publishedYes


  • AMP-Activated Protein Kinases/genetics
  • Activating Transcription Factor 1/genetics
  • Animals
  • Cells, Cultured
  • DNA-Binding Proteins/genetics
  • Disease Models, Animal
  • Erythrocytes/metabolism
  • Female
  • Hematoma/genetics
  • Heme Oxygenase-1/genetics
  • Insulin-Like Growth Factor I/genetics
  • Iron/metabolism
  • Lipid Metabolism
  • Liver X Receptors/genetics
  • Macrophages/metabolism
  • Male
  • Membrane Proteins/genetics
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Oxidative Stress
  • Time Factors

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