TitleUrokinase plasminogen activator induces pro-fibrotic/m2 phenotype in murine cardiac macrophages.
Publication TypeJournal Article
Year of Publication2013
AuthorsMeznarich, J, Malchodi, L, Helterline, D, Ramsey, SA, Bertko, K, Plummer, T, Plawman, A, Gold, E, Stempien-Otero, A
JournalPLoS One
Date Published2013
KeywordsAnimals, Cell Movement, Cell Polarity, Collagen, Fibroblasts, Fibrosis, Gene Expression, Gene Expression Profiling, Inflammation Mediators, Interleukin-6, Macrophage Activation, Macrophages, Mice, Mice, Transgenic, Myocardium, Phenotype, Transcription, Genetic, Urokinase-Type Plasminogen Activator

OBJECTIVE: Inflammation and fibrosis are intertwined in multiple disease processes. We have previously found that over-expression of urokinase plasminogen activator in macrophages induces spontaneous macrophage accumulation and fibrosis specific to the heart in mice. Understanding the relationship between inflammation and fibrosis in the heart is critical to developing therapies for diverse myocardial diseases. Therefore, we sought to determine if uPA induces changes in macrophage function that promote cardiac collagen accumulation.

METHODS AND RESULTS: We analyzed the effect of the uPA transgene on expression of pro-inflammatory (M1) and pro-fibrotic (M2) genes and proteins in hearts and isolated macrophages of uPA overexpressing mice. We found that although there was elevation of the pro-inflammatory cytokine IL-6 in hearts of transgenic mice, IL-6 is not a major effector of uPA induced cardiac fibrosis. However, uPA expressing bone marrow-derived macrophages are polarized to express M2 genes in response to IL-4 stimulation, and these M2 genes are upregulated in uPA expressing macrophages following migration to the heart. In addition, while uPA expressing macrophages express a transcriptional profile that is seen in tumor-associated macrophages, these macrophages promote collagen expression in cardiac but not embryonic fibroblasts.

CONCLUSIONS: Urokinase plasminogen activator induces an M2/profibrotic phenotype in macrophages that is fully expressed after migration of macrophages into the heart. Understanding the mechanisms by which uPA modulates macrophage function may reveal insights into diverse pathologic processes.

Alternate JournalPLoS One
PubMed ID23536772
PubMed Central IDPMC3594198
Grant ListK08 HL070941 / HL / NHLBI NIH HHS / United States
K25 HL098807 / HL / NHLBI NIH HHS / United States
K08HL70941 / HL / NHLBI NIH HHS / United States