scholarly journals Myofibroblast differentiation is governed by adhesion mechanics, and inhibition of the stress sensor Talin2 reverses lung fibrosis

2021 ◽  
Author(s):  
MICHAEL John Victor WHITE ◽  
Melis Ozkan ◽  
Jorge Emiliano Gomez Medellin ◽  
Jeffrey Hubbell
Keyword(s):  
Lung Fibrosis ◽  
Smooth Muscle Actin ◽  
The United States ◽  
Myofibroblast Differentiation ◽  
Muscle Actin ◽  
Protein Target ◽  
Novel Treatment ◽  
Adhesion Mechanics ◽  
Novel Targets ◽  
Novel Protein

Fibrosis is involved in 45% of deaths in the United States, and no treatment exists to reverse progression of the disease. In order to find novel targets for fibrosis therapeutics, we developed a model for the differentiation of monocytes to myofibroblasts that allowed us to screen for proteins involved in myofibroblast differentiation. We assessed these screening results for proteins to target for novel fibrosis therapeutics. Here we test whether inhibition of a novel protein target generated by our model, talin2, can prevent and even reverse myofibroblast differentiation. We find that knockdown of talin2 de-differentiates myofibroblasts, altering myofibroblast morphology, α-smooth muscle actin and collagen content, and the secretome. Talin2 inhibition reverses bleomycin-induced lung fibrosis in mice. Talin2 inhibition could be a novel treatment for reversing lung fibrosis.

scholarly journals Myofibroblast transcriptome indicates SFRP2+ fibroblast progenitors in systemic sclerosis skin

2021 ◽  
Author(s):  
Tracy Tabib ◽  
Mengqi Huang ◽  
Nina Morse ◽  
Anna Papazoglou ◽  
Rithika Behera ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Transcription Factors ◽  
Systemic Sclerosis ◽  
Lung Fibrosis ◽  
Smooth Muscle Actin ◽  
Cell Types ◽  
Myofibroblast Differentiation ◽  
Muscle Actin ◽  
Alpha Smooth Muscle Actin ◽  
Single Cell Rna Sequencing

ABSTRACTSkin and lung fibrosis in systemic sclerosis (SSc) is driven by myofibroblasts, alpha-smooth muscle actin expressing cells that arise from a variety of cell types in murine fibrosis models. Utilizing single cell RNA-sequencing to examine the transcriptome changes, we show that SSc dermal myofibroblasts arise from an SFRP2/DPP4-expressing progenitor fibroblast population that globally upregulates expression of transcriptome markers, such as PRSS23 and THBS1. Only a fraction of SSc fibroblasts differentiate into myofibroblasts, as shown by expression of additional markers, SFRP4 and FNDC1. The myofibroblast transcriptome implicates upstream transcription factors that drive myofibroblast differentiation.

scholarly journals Focal adhesion size controls tension-dependent recruitment of α-smooth muscle actin to stress fibers

2006 ◽  
Vol 172 (2) ◽  
pp. 259-268 ◽  
Author(s):  
Jérôme M. Goffin ◽  
Philippe Pittet ◽  
Gabor Csucs ◽  
Jost W. Lussi ◽  
Jean-Jacques Meister ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Focal Adhesion ◽  
Stress Resistance ◽  
Smooth Muscle Actin ◽  
Focal Adhesions ◽  
Stress Fibers ◽  
Myofibroblast Differentiation ◽  
Muscle Actin ◽  
High Tension ◽  
Tension Generation

Expression of α-smooth muscle actin (α-SMA) renders fibroblasts highly contractile and hallmarks myofibroblast differentiation. We identify α-SMA as a mechanosensitive protein that is recruited to stress fibers under high tension. Generation of this threshold tension requires the anchoring of stress fibers at sites of 8–30-μm-long “supermature” focal adhesions (suFAs), which exert a stress approximately fourfold higher (∼12 nN/μm2) on micropatterned deformable substrates than 2–6-μm-long classical FAs. Inhibition of suFA formation by growing myofibroblasts on substrates with a compliance of ≤11 kPa and on rigid micropatterns of 6-μm-long classical FA islets confines α-SMA to the cytosol. Reincorporation of α-SMA into stress fibers is established by stretching 6-μm-long classical FAs to 8.1-μm-long suFA islets on extendable membranes; the same stretch producing 5.4-μm-long classical FAs from initially 4-μm-long islets is without effect. We propose that the different molecular composition and higher phosphorylation of FAs on supermature islets, compared with FAs on classical islets, accounts for higher stress resistance.

scholarly journals Neuronal Wiskott-Aldrich syndrome protein (N-WASP) is critical for formation of α-smooth muscle actin filaments during myofibroblast differentiation

2012 ◽  
Vol 303 (8) ◽  
pp. L692-L702 ◽  
Author(s):  
Guo-Qiang Cai ◽  
Chu-Fang Chou ◽  
Meng Hu ◽  
Anni Zheng ◽  
Louis F. Reichardt ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Actin ◽  
Critical Role ◽  
Lung Fibroblasts ◽  
Myofibroblast Differentiation ◽  
Muscle Actin ◽  
Wiskott Aldrich Syndrome ◽  
Cytoplasmic Filaments ◽  
Syndrome Protein ◽  
Tgf Β1

Myofibroblasts are implicated in pathological stromal responses associated with lung fibrosis. One prominent phenotypic marker of fully differentiated myofibroblasts is the polymerized, thick cytoplasmic filaments containing newly synthesized α-smooth muscle actin (α-SMA). These α-SMA-containing cytoplasmic filaments are important for myofibroblast contractility during tissue remodeling. However, the molecular mechanisms regulating the formation and maturation of α-SMA-containing filaments have not been defined. This study demonstrates a critical role for neuronal Wiskott-Aldrich syndrome protein (N-WASP) in regulating the formation of α-SMA-containing cytoplasmic filaments during myofibroblast differentiation and in myofibroblast contractility. Focal adhesion kinase (FAK) is activated by transforming growth factor-β1 (TGF-β1) and is required for phosphorylation of tyrosine residue 256 (Y256) of N-WASP. Phosphorylation of Y256 of N-WASP is essential for TGF-β1-induced formation of α-SMA-containing cytoplasmic filaments in primary human lung fibroblasts. In addition, we demonstrate that actin-related protein (Arp) 2/3 complex is downstream of N-WASP and mediates the maturation of α-SMA-containing cytoplasmic filaments. Together, this study supports a critical role of N-WASP in integrating FAK and Arp2/3 signaling to mediate formation of α-SMA-containing cytoplasmic filaments during myofibroblast differentiation and maturation.

Acidic fibroblast growth factor decreases α-smooth muscle actin expression and induces apoptosis in human normal lung fibroblasts

2006 ◽  
Vol 291 (5) ◽  
pp. L871-L879 ◽  
Author(s):  
Carlos Ramos ◽  
Martha Montaño ◽  
Carina Becerril ◽  
José Cisneros-Lira ◽  
Lourdes Barrera ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Growth Rate ◽  
Smooth Muscle ◽  
Caspase 3 ◽  
Smooth Muscle Actin ◽  
Myofibroblast Differentiation ◽  
Fibroblast Growth ◽  
Muscle Actin ◽  
Acidic Fibroblast Growth Factor ◽  
Tgf Β1

Fibroblast/myofibroblast expansion is critical in the pathogenesis of pulmonary fibrosis. To date, most research has focused on profibrotic mediators, whereas studies on antifibrotic factors are scanty. In this study, we explored the effects of acidic fibroblast growth factor (FGF-1) and FGF-1 plus heparin (FGF-1+H) on fibroblast growth rate, apoptosis, and myofibroblast differentiation. Heparin was used because it participates in FGF-1 signaling. Growth rate was evaluated by WST-1 colorimetric assay, DNA synthesis by [3H]thymidine incorporation, and apoptosis by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) and cleaved caspase 3. Expression of α-smooth muscle actin (α-SMA) was examined by immunocytochemistry, flow cytometry, real-time PCR, and immunoblotting. Despite the induction of DNA synthesis, FGF-1+H significantly reduced fibroblast growth rate. This correlated with a significant increase in apoptosis, evaluated by TUNEL (41.6 ± 1.4% vs. 12.5 ± 0.6% from controls; P < 0.01) and cleaved caspase 3 (295 ± 32 vs. 200 ± 19 ng/106 cells from controls; P < 0.05). Double immunostaining (α-SMA-TUNEL) revealed that the levels of induced apoptosis were similar in fibroblasts and myofibroblasts. FGF-1+H inhibited the effect of TGF-β1 on myofibroblast differentiation. α-SMA-positive cells were reduced by immunocytochemistry from 44.5 ± 6.5% to 10.9 ± 1.9% and by flow cytometry from 30.6 ± 2.5% to 7.7 ± 0.6% ( P < 0.01). Also, FGF-1+H significantly inhibited the TGF-β1 induction of α-SMA quantified by real-time PCR and Western blot. This decrease was associated with a 35% reduction in TGF-β1-induced collagen gel contraction. The effect of FGF-1+H was mediated by a significant decrease of TGF-β1-induced Smad2 phosphorylation. FGF-1 alone exhibited similar but lower effects. These findings suggest that FGF-1 can have an antifibrogenic role, inducing apoptosis of fibroblasts and inhibiting myofibroblast differentiation.

Increased Alveolar Concentration of Nitric Oxide Is Related to Serum-induced Lung Fibroblast Proliferation in Patients with Systemic Sclerosis

2010 ◽  
Vol 37 (8) ◽  
pp. 1680-1687 ◽  
Author(s):  
THONG HUA-HUY ◽  
KIET PHONG TIEV ◽  
CHRISTIANE CHÉREAU ◽  
SY DUONG-QUY ◽  
JEAN CABANE ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Systemic Sclerosis ◽  
Lung Fibrosis ◽  
Smooth Muscle Actin ◽  
Lung Fibroblast ◽  
Fibroblast Proliferation ◽  
Muscle Actin ◽  
Brdu Labeling ◽  
Actin Expression ◽  
Pulmonary Fibroblast

Objective.Lung inflammation is present in patients with systemic sclerosis (SSc) and interstitial lung disease (ILD), but the mechanisms linking inflammatory and fibrotic processes in ILD are unknown. Our aim was to investigate whether alveolar inflammation, reflected by increased alveolar concentration of exhaled nitric oxide (CANO), is related to the ability of serum from patients with SSc to induce pulmonary fibroblast proliferation (PFP) and myofibroblast conversion.Methods.CANO was measured in all subjects (37 patients with SSc and 10 healthy controls) whose sera were used to stimulate PFP (assessed by BrdU labeling index) and myofibroblast conversion (detected by α-smooth muscle actin expression). The PFP index in patients with SSc was compared to control values, and between patients with SSc who had elevated (> 4.3 ppb) and normal (≤ 4.3 ppb) CANO values.Results.Both CANO and the PFP index were significantly greater in patients with SSc compared to controls. In patients with SSc, the PFP index was directly related to CANO levels (r = 0.48; p = 0.002). The median PFP index was significantly higher in patients with SSc who had elevated CANO (> 4.3 ppb; n = 25, median 1.1, range 0.98–1.23) than in patients with SSc who had normal CANO (≤ 4.3 ppb; n = 12, median 0.93, range 0.82–1.08; p = 0.01). Similarly, myofibroblast conversion induced by SSc serum was significantly greater in patients with CANO > 4.3 ppb than in patients whose CANO was ≤ 4.3 ppb (p < 0.001) and controls (p < 0.001).Conclusion.Alveolar inflammation reflected by increased nitric oxide production was related to serum-induced PFP and myofibroblast conversion, linking the active alveolitis process to cell proliferation and lung fibrosis in patients with SSc.

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