Heme detoxification by heme oxygenase-1 reinstates proliferative and immune balances upon genotoxic tissue injury.

ABSTRACT: Phenotypic changes of myeloid cells are critical to the regulation of premature aging, development of cancer, and responses to infection. Heme metabolism has a fundamental role in the regulation of myeloid cell function and activity. Here, we show that deletion of heme oxygenase-1 (HO-1), an enzyme that removes heme, results in an impaired DNA damage response (DDR), reduced cell proliferation, and increased cellular senescence. We detected increased levels of p16INK4a, H2AX?, and senescence-associated-?-galactosidase (SA-?-Gal) in cells and tissues isolated from HO-1-deficient mice. Importantly, deficiency of HO-1 in residential macrophages in chimeric mice results in elevated DNA damage and senescence upon radiation-induced injury. Mechanistically, we found that mammalian target of rapamycin (mTOR)/S6 protein signaling is critical for heme and HO-1-regulated phenotype of macrophages. Collectively, our data indicate that HO-1, by detoxifying heme, blocks p16INK4a expression in macrophages, preventing DNA damage and cellular senescence.

SUBMITTER: Hedblom A 

PROVIDER: S-EPMC6347604 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature