Dataset Information

Myofibroblast-specific Smad7 protects the pressure-overloaded heart by restraining collagen deposition and denaturation, and by inhibiting paracrine macrophage activation

ABSTRACT: Rationale: Expansion and activation of cardiac fibroblasts contributes to adverse remodeling, fibrosis and dysfunction in the pressure-overloaded heart. Although early fibroblast TGF-β/Smad3 activation protects the pressure overloaded heart by preserving the matrix, sustained TGF-β activation may be deleterious, accentuating fibrosis and dysfunction. Thus, endogenous mechanisms that negatively regulate the TGF- response in fibroblasts may be required to protect from progressive fibrosis and adverse remodeling. Objective: To study the role of fibroblast-specific induction of Smad7, an inhibitory Smad that restrains TGF-β signaling, in regulation of fibrosis, remodeling and dysfunction of the pressure-overloaded heart. Methods and Results: In a mouse model of pressure overload induced through transverse aortic constriction (TAC), Smad7 was upregulated in cardiac fibroblasts and myofibroblasts. Mice with myofibroblast-specific loss of Smad7 (MFS7KO) had increased mortality, accentuated systolic dysfunction and dilative remodeling, and accelerated diastolic dysfunction in response to TAC. Increased dysfunction in MFS7KO hearts was associated with accentuated fibrosis and increased collagen denaturation, in the absence of effects on cardiomyocyte death. Secretomic analysis showed that Smad7 loss accentuates secretion of structural collagens and matricellular proteins, and markedly increases secretion of matrix metalloproteinase-2 (MMP2). In a 3D model of fibroblasts populating collagen lattices the effects of Smad7 on fibroblast-induced collagen denaturation and pad contraction were partly mediated via MMP2 downregulation. Surprisingly, MFS7KO mice also exhibited significant macrophage expansion caused by paracrine actions of Smad7 null fibroblasts that stimulate macrophage proliferation and fibrogenic activation. Secretomic analysis and in vitro experiments suggested that macrophage activation involves the combined effects of the fibroblast-derived matricellular proteins CD5L, SPARC, CTGF, ECM1 and TGFBI. Conclusions: The anti-fibrotic effects of Smad7 in the pressure-overloaded heart protect from dysfunction and involve not only reduction in collagen deposition, but also suppression of MMP2-mediated matrix denaturation and paracrine effects that suppress macrophage activation through inhibition of matricellular proteins.

INSTRUMENT(S): Orbitrap Fusion Lumos

ORGANISM(S): Mus Musculus (mouse)

TISSUE(S): Heart

SUBMITTER: Simone Sidoli

LAB HEAD: Simone Sidoli

PROVIDER: PXD043577 | Pride | 2025-07-28

REPOSITORIES: Pride

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Dataset's files

Source:

			Action	DRS
	20200702_Jenny_Claudio_57T6_1.msf	Msf
	20200702_Jenny_Claudio_57T6_1.raw	Raw
	20200702_Jenny_Claudio_57T6_2.raw	Raw
	20200702_Jenny_Claudio_57T6_3.raw	Raw
	20200702_Jenny_Claudio_57WT_1.raw	Raw

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Publications

Fibroblast Smad7 Induction Protects the Remodeling Pressure-Overloaded Heart.

Humeres Claudio C Shinde Arti V AV Tuleta Izabela I Hernandez Silvia C SC Hanna Anis A Huang Shuaibo S Venugopal Harikrishnan H Aguilan Jennifer T JT Conway Simon J SJ Sidoli Simone S Frangogiannis Nikolaos G NG

Circulation research 20240620 3

<h4>Background</h4>Cardiac fibroblast activation contributes to adverse remodeling, fibrosis, and dysfunction in the pressure-overloaded heart. Although early fibroblast TGF-β (transforming growth factor-β)/Smad (small mother against decapentaplegic)-3 activation protects the pressure-overloaded heart by preserving the matrix, sustained TGF-β activation is deleterious, accentuating fibrosis and dysfunction. Thus, endogenous mechanisms that negatively regulate the TGF-β response in fibroblasts ma ...[more]

PMID: 38899461

Similar Datasets

Project description:Rationale: Expansion and activation of cardiac fibroblasts contributes to adverse remodeling, fibrosis and dysfunction in the pressure-overloaded heart. Although early fibroblast TGF-β/Smad3 activation protects the pressure overloaded heart by preserving the matrix, sustained TGF-β activation may be deleterious, accentuating fibrosis and dysfunction. Thus, endogenous mechanisms that negatively regulate the TGF- response in fibroblasts may be required to protect from progressive fibrosis and adverse remodeling. Objective: To study the role of fibroblast-specific induction of Smad7, an inhibitory Smad that restrains TGF-β signaling, in regulation of fibrosis, remodeling and dysfunction of the pressure-overloaded heart. Methods and Results: In a mouse model of pressure overload induced through transverse aortic constriction (TAC), Smad7 was upregulated in cardiac myofibroblasts. Mice with myofibroblast-specific loss of Smad7 (MFS7KO) had increased mortality, accentuated systolic dysfunction and dilative remodeling, and accelerated diastolic dysfunction in response to TAC. Increased dysfunction in MFS7KO hearts was associated with accentuated fibrosis and increased collagen denaturation, in the absence of effects on cardiomyocyte death. Secretomic analysis showed that Smad7 loss accentuates secretion of structural collagens and matricellular proteins, and markedly increases secretion of matrix metalloproteinase-2 (MMP2). In a 3D model of fibroblasts populating collagen lattices the effects of Smad7 on fibroblast-induced collagen denaturation and pad contraction were partly mediated via MMP2 downregulation. Surprisingly, MFS7KO mice also exhibited significant macrophage expansion caused by paracrine actions of Smad7 null fibroblasts that stimulate macrophage proliferation and fibrogenic activation. Secretomic analysis and in vitro experiments suggested that macrophage activation involves the combined effects of the fibroblast-derived matricellular proteins CD5L, SPARC, CTGF, ECM1 and TGFBI. Conclusions: The anti-fibrotic effects of Smad7 in the pressure-overloaded heart protect from dysfunction and involve not only reduction in collagen deposition, but also suppression of MMP2-mediated matrix denaturation and paracrine effects that suppress macrophage activation through inhibition of matricellular proteins.

Project description:Induction of the inhibitory Smad, Smad7 serves as a negative feedback mechanism that restrains TGF-b-mediated actions in injured tissues. In inflammatory cells, Smad7 has been suggested to exert both pro-inflammatory actions attributed to inhibition of TGF-b-induced suppression of inflammation, and anti-inflammatory effects due to disruption of the TAK-1/NF-kB system. Myocardial infarction triggers a macrophage-driven inflammatory response that plays a central role in cardiac repair, but also contributes to adverse remodeling and fibrosis. We hypothesized that Smad7 upregulation in infarct macrophages may play a modulatory role in cardiac repair, by restraining effects of TGF-b. To test the hypothesis, we investigated the response of Myeloid cell-specific Smad7 knockout mice (MyS7KO) following myocardial infarction protocols, and we examined the in vitro effects of Smad7 in isolated macrophages. Smad7 was upregulated in a subset of infarct macrophages, peaking 7 days after infarction. Myeloid cell-specific Smad7 loss did not affect baseline macrophage gene expression and had no significant effects on homeostatic functions. Although RNA-seq analysis predicted that, in the absence of Smad7, infarct macrophages may have attenuated activation of inflammatory pathways and suppressed TREM1 signaling, myeloid cell-specific Smad7 loss had no significant effects on ventricular dysfunction, adverse remodeling, scar remodeling and collagen deposition after myocardial infarction. In isolated macrophages, TGF-b attenuated pro-inflammatory cytokine and chemokine expression, modulated synthesis of matrix remodeling genes, and had profound effects on macrophage profile, inducing genes associated with activation of sphingosine-1 phosphate and integrin signaling pathways, and inhibiting cholesterol biosynthesis genes. However, RNA-seq and PCR array experiments showed that Smad7 loss has minimal effects on TGF-b-mediated macrophage responses, restraining synthesis of only a small fraction of TGF-b-induced genes, such as Itga5, Olfml3 and Fabp7. Smad7 absence did not affect the anti-inflammatory actions of TGF-b in TNF-stimulated cells. In conclusion, our findings suggest a limited role for macrophage Smad7 in regulation of post-infarction inflammation and repair, and demonstrate that the anti-inflammatory effects of TGF-b in macrophages are not restrained by endogenous Smad7 induction.