Potential Role of Heme Oxygenase-1 in the Resolution of Experimentally Induced Colitis through Regulation of Macrophage Polarization

Autor: Shin-Young Gwak, Su-Jung Kim, Jeongmin Park, Seung Hyeon Kim, Yeonsoo Joe, Ha-Na Lee, Wonki Kim, Ishrat Aklima Muna, Hye-Kyung Na, Hun Taeg Chung, Young-Joon Surh
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Gut and Liver, Vol 16, Iss 2, Pp 246-258 (2022)
Druh dokumentu: article
ISSN: 1976-2283
DOI: 10.5009/gnl210058
Popis: Background/Aims: Heme oxygenase-1 (HO-1) plays a central role in cellular defense against inflammatory insults, and its induction in macrophages potentiates their efferocytic activity. In this study, we explored the potential role of macrophage HO-1 in the resolution of experimentally induced colitis. Methods: To induce colitis, male C57BL/6 mice were treated with 2% dextran sulfate sodium (DSS) in the drinking water for 7 days. To investigate efferocytosis, apoptotic colon epithelial CCD 841 CoN cells were coincubated with bone marrow-derived macrophages (BMDMs). Results: Administration of the HO-1 inhibitor zinc protoporphyrin IX (ZnPP) blunted the resolution of DSS-induced intestinal inflammation and expression of the proresolving M2 macrophage marker CD206. BMDMs treated with apoptotic colonic epithelial cells showed significantly elevated expression of HO-1 and its regulator Nrf2. Under the same experimental conditions, the proportion of CD206-expressing macrophages was also enhanced. ZnPP treatment abrogated the upregulation of CD206 expression in BMDMs engulfing apoptotic colonic epithelial cells. This result was verified with BMDMs isolated from HO-1-knockout mice. BMDMs, when stimulated with lipopolysaccharide, exhibited increased expression of CD86, a marker of M1 macrophages. Coculture of lipopolysaccharide-stimulated BMDMs with apoptotic colonic epithelial cell debris dampened the expression of CD86 as well as the pro-inflammatory cytokines in an HO-1-dependent manner. Genetic ablation as well as pharmacologic inhibition of HO-1 significantly reduced the proportion of efferocytic BMDMs expressing the scavenger receptor CD36. Conclusions: HO-1 plays a key role in the resolution of experimentally induced colitis by modulating the polarization of macrophages.
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