Interstitial macrophage-derived thrombospondin-1 contributes to hypoxia-induced pulmonary hypertension.
Cardiovasc Res 2020;
116:2021-2030. [PMID:
31710666 PMCID:
PMC7519884 DOI:
10.1093/cvr/cvz304]
[Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 03/06/2019] [Accepted: 11/08/2019] [Indexed: 01/05/2023] Open
Abstract
AIMS
Transforming growth factor-β (TGF-β) signalling is required for chronic hypoxia-induced pulmonary hypertension (PH). The activation of TGF-β by thrombospondin-1 (TSP-1) contributes to the pathogenesis of hypoxia-induced PH. However, neither the cellular source of pathologic TSP-1 nor the downstream signalling pathway that link activated TGF-β to PH have been determined. In this study, we hypothesized that circulating monocytes, which are recruited to become interstitial macrophages (IMs), are the major source of TSP-1 in hypoxia-exposed mice, and TSP-1 activates TGF-β with increased Rho-kinase signalling, causing vasoconstriction.
METHODS AND RESULTS
Flow cytometry revealed that a specific subset of IMs is the major source of pathologic TSP-1 in hypoxia. Intravenous depletion and parabiosis experiments demonstrated that these cells are circulating prior to recruitment into the interstitium. Rho-kinase-mediated vasoconstriction was a major downstream target of active TGF-β. Thbs1 deficient bone marrow (BM) protected against hypoxic-PH by blocking TGF-β activation and Rho-kinase-mediated vasoconstriction.
CONCLUSION
In hypoxia-challenged mice, BM derived and circulating monocytes are recruited to become IMs which express TSP-1, resulting in TGF-β activation and Rho-kinase-mediated vasoconstriction.
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