Fibrotic Signaling in Cardiac Fibroblasts and Vascular Smooth Muscle Cells: The Dual Roles of Fibrosis in HFpEF and CAD

Figures

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  Figure 2. Extracellular matrix (ECM) gene expression in primary human cardiac fibroblasts and primary human coronary artery vascular smooth muscle cells varies in different in vitro phenotypes. (A) Schematic overview of cell types used and experimental set-up. Commercially available human primary left ventricular cardiac fibroblasts (CF, Cat# CC-2904, Lonza, Basel, Switzerland) and primary human coronary artery vascular smooth muscle cells (VSMC, Cat# 121 0612, Provitro, Berlin, Germany) from three organ donors for each cell type were seeded in 6-well plates in passage six. CFs were cultured in growth media containing 10% fetal bovine serum (FBS, Cat# 16140071, Thermo Fischer Scientific, Waltham, MA, USA) and stimulated with 10 µmol/l transforming growth factor (TGF) β receptor (TGFβR) I inhibitor (Cat# SB421542, Sigma, St. Louis, MI, USA) and 25 µmol/L Rho-associated kinase (ROCK) inhibitor (Cat# Y27632, BD Biosciences, Heidelberg, Germany) for 48 h, or 10 ng/mL TGF-β1 (Cat# 7754-BH, R&D Systems, Minneapolis, MN, USA) for 24 h. VSMC were cultured in growth media containing 10% FBS or in serum starvation media containing 0.5% FBS for 72 h, with subsequent stimulation with 10 ng/mL TGF-β1…

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  Figure 1. Dual roles of fibrotic remodeling in cardiovascular disease. Targeting ECM remodeling to reduce cardiac fibrosis in patients with Heart Failure with Preserved Ejection Fraction (HFpEF) and atherosclerosis-driven coronary artery disease (CAD) may entail a risk of destabilizing coronary atherosclerotic plaques, thereby causing myocardial infarction (MI). Cardiac fibroblasts (CFs) and vascular smooth muscle cells (VSMCs) regulate fibrotic remodeling of the myocardium and atherosclerotic plaque, respectively. They change phenotype in response to pathological stress and increase their production of ECM. These ECM-producing pathological CFs and VSMCs are given different names in the literature (as listed in the figure), depending on their phenotype, but may indicate similar subpopulations. These described cells are central for the induction of interstitial and perivascular fibrosis in HF patients and stabilization of the coronary atherosclerotic plaques in patients with CAD. The optimal treatment of patients with HFpEF and CAD should reduce cardiac fibrosis while maintaining, or promoting, a stable atherosclerotic plaque.

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  Figure 3. Signaling pathways that drive extracellular matrix remodeling in cardiac fibroblasts and vascular smooth muscle cells. Many signaling pathways that induce changes in gene expression, such as Wnt, Platelet-Derived Growth Factor (PDGF), interleukin (IL)-1, IL-6, IL-11, IL-17 and IL-18, and mechanical signaling, do so by affecting Transforming Growth Factor (TGF)-β and Angiotensin (Ang) II signaling. TGF-β and Ang II will, in turn, affect gene expression leading to extracellular matrix (ECM) synthesis or degradation through their multiple, and overlapping, downstream signaling pathways. Thus, TGF-β and Ang II are central in regulating the homeostasis of ECM turnover. NFĸB, nuclear factor kappa B; PKC, protein kinase C; MAPK, Mitogen-Activated Protein Kinase; ERK, Extracellular signal-regulated kinase 1/2; JNK, Jun N-terminal kinases; MRTF, Myocardin-Related Transcription Factor, ROCK, Rho-associated protein kinase; Smad, Suppressor of Mothers against Decapentaplegic.