Mechanical stretch sustains myofibroblast phenotype and function in microtissues through latent TGF-β1 activation

AbstractFibrosis is a leading cause of death in developed countries that is characterized by a progressive deterioration of tissue mechanical behavior. Developing methods to study tissue mechanics and myofibroblast activation may lead to new targets for therapeutic treatments that are urgently needed. Microtissue arrays are a promising approach to conduct relatively high throughput research into fibrosis as they recapitulate key biomechanical aspects of the disease through a relevant 3D extracellular environment. In early work, our group developed a device called the MVAS-force to stretch microtissues while enabling simultaneous assessment of their dynamic mechanical behavior. Here we investigated TGF-β1 induced fibroblast to myofibroblast differentiation in microtissue cultures using our MVAS-force device through assessing α-SMA expression, contractility and stiffness. By doing so, we linked cell-level phenotypic changes to functional changes that characterize the clinical manifestation of fibrotic disease. As expected, TGF-β1 treatment promoted a myofibroblastic phenotype and microtissues became stiffer and possessed increased contractility. Furthermore, these changes were partially reversible upon TGF-β1 withdrawal. In contrast, however, long-term cyclic stretching maintained myofibroblast activation. Furthermore stretching had no effect compared static cultures when TGF-β1 receptors were inhibited and stretching promoted myofibroblast differentiation when given latent TGF-β1. Together these results suggest that external mechanical stretch may activate latent TGF-β1 and might be a powerful stimulus for continued myofibroblast activation to progress fibrosis. Further exploration of this pathway with our approach may yield new insights into myofibroblast activation and more effective therapeutic treatments for fibrosis.Insight boxUsing a novel high-throughput approach, we quantified the effects of dynamic mechanical stretching on the phenotype and function of cells in 3D microtissue cultures during myofibroblast activation with TGF-β1 treatment and subsequent withdrawal. Our findings show that mechanical stretch may activate endogenously produced latent TGF-β1 to maintain the presence and activity of myofibroblasts after tissue injury. Importantly, through this feed forward mechanism, mechanical stretch might be a powerful stimulus that directs tissues away from recovery and towards the development of fibrosis.

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Mechanical stretch sustains myofibroblast phenotype and function in microtissues through latent TGF-β1 activation

Integrative Biology ◽

10.1093/intbio/zyaa015 ◽

2020 ◽

Vol 12 (8) ◽

pp. 199-210 ◽

Cited By ~ 1

Author(s):

Matthew Walker ◽

Michel Godin ◽

Andrew E Pelling

Keyword(s):

Static Condition ◽

Mechanical Stretch ◽

Tissue Mechanics ◽

Myofibroblast Differentiation ◽

Fibrotic Disease ◽

Functional Changes ◽

Cyclic Stretching ◽

Powerful Stimulus ◽

And Function ◽

Tgf Β1

Abstract Developing methods to study tissue mechanics and myofibroblast activation may lead to new targets for therapeutic treatments that are urgently needed for fibrotic disease. Microtissue arrays are a promising approach to conduct relatively high-throughput research into fibrosis as they recapitulate key biomechanical aspects of the disease through a relevant 3D extracellular environment. In early work, our group developed a device called the MVAS-force to stretch microtissues while enabling simultaneous assessment of their dynamic mechanical behavior. Here, we investigated TGF-β1-induced fibroblast to myofibroblast differentiation in microtissue cultures using our MVAS-force device through assessing α-SMA expression, contractility and stiffness. In doing so, we linked cell-level phenotypic changes to functional changes that characterize the clinical manifestation of fibrotic disease. As expected, TGF-β1 treatment promoted a myofibroblastic phenotype and microtissues became stiffer and possessed increased contractility. These changes were partially reversible upon TGF-β1 withdrawal under a static condition, while, in contrast, long-term cyclic stretching maintained myofibroblast activation. This pro-fibrotic effect of mechanical stretching was absent when TGF-β1 receptors were inhibited. Furthermore, stretching promoted myofibroblast differentiation when microtissues were given latent TGF-β1. Altogether, these results suggest that external mechanical stretch may activate latent TGF-β1 and, accordingly, might be a powerful stimulus for continued myofibroblast activation to progress fibrosis. Further exploration of this pathway with our approach may yield new insights into myofibroblast activation and more effective therapeutic treatments for fibrosis.

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Role of Cardiac Macrophages on Cardiac Inflammation, Fibrosis and Tissue Repair

Cells ◽

10.3390/cells10010051 ◽

2020 ◽

Vol 10 (1) ◽

pp. 51

Author(s):

William P. Lafuse ◽

Daniel J. Wozniak ◽

Murugesan V. S. Rajaram

Keyword(s):

Tissue Damage ◽

Tissue Repair ◽

Cardiac Tissue ◽

Tissue Injury ◽

The Body ◽

T And B Cells ◽

Functional Changes ◽

Cardiac Inflammation ◽

And Function

The immune system plays a pivotal role in the initiation, development and resolution of inflammation following insult or damage to organs. The heart is a vital organ which supplies nutrients and oxygen to all parts of the body. Heart failure (HF) has been conventionally described as a disease associated with cardiac tissue damage caused by systemic inflammation, arrhythmia and conduction defects. Cardiac inflammation and subsequent tissue damage is orchestrated by the infiltration and activation of various immune cells including neutrophils, monocytes, macrophages, eosinophils, mast cells, natural killer cells, and T and B cells into the myocardium. After tissue injury, monocytes and tissue-resident macrophages undergo marked phenotypic and functional changes, and function as key regulators of tissue repair, regeneration and fibrosis. Disturbance in resident macrophage functions such as uncontrolled production of inflammatory cytokines, growth factors and inefficient generation of an anti-inflammatory response or unsuccessful communication between macrophages and epithelial and endothelial cells and fibroblasts can lead to aberrant repair, persistent injury, and HF. Therefore, in this review, we discuss the role of cardiac macrophages on cardiac inflammation, tissue repair, regeneration and fibrosis.

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Apigenin Alleviates Renal Fibroblast Activation through AMPK and ERK Signaling Pathways In Vitro

Current Pharmaceutical Biotechnology ◽

10.2174/1389201021666200320140908 ◽

2020 ◽

Vol 21 (11) ◽

pp. 1107-1118

Author(s):

Ningning Li ◽

Zhan Wang ◽

Tao Sun ◽

Yanfei Lei ◽

Xianghua Liu ◽

...

Keyword(s):

Renal Fibrosis ◽

Transforming Growth Factor ◽

Therapeutic Potential ◽

Protective Role ◽

Fibroblast Proliferation ◽

Fibroblast Activation ◽

And Function ◽

Activated Fibroblasts ◽

Tgf Β1

Objective: Renal fibrosis is a common pathway leading to the progression of chronic kidney disease. Activated fibroblasts contribute remarkably to the development of renal fibrosis. Although apigenin has been demonstrated to play a protective role from fibrotic diseases, its pharmacological effect on renal fibroblast activation remains largely unknown. Materials and Methods: Here, we examined the functional role of apigenin in the activation of renal fibroblasts response to transforming growth factor (TGF)-β1 and its potential mechanisms. Cultured renal fibroblasts (NRK-49F) were exposed to apigenin (1, 5, 10 and 20 μM), followed by the stimulation of TGF-β1 (2 ng/mL) for 24 h. The markers of fibroblast activation were determined. In order to confirm the anti-fibrosis effect of apigenin, the expression of fibrosis-associated genes in renal fibroblasts was assessed. As a consequence, apigenin alleviated fibroblast proliferation and fibroblastmyofibroblast differentiation induced by TGF-β1. Result: Notably, apigenin significantly inhibited the fibrosis-associated genes expression in renal fibroblasts. Moreover, apigenin treatment significantly increased the phosphorylation of AMP-activated protein kinase (AMPK). Apigenin treatment also obviously reduced TGF-β1 induced phosphorylation of ERK1/2 but not Smad2/3, p38 and JNK MAPK in renal fibroblasts. Conclusion: In a summary, these results indicate that apigenin inhibits renal fibroblast proliferation, differentiation and function by AMPK activation and reduced ERK1/2 phosphorylation, suggesting it could be an attractive therapeutic potential for the treatment of renal fibrosis.

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Dynamic Mechanical Behavior of Hybrid Flax/Basalt Fiber Polymer Composites

Mechanical and Dynamic Properties of Biocomposites ◽

10.1002/9783527822331.ch17 ◽

2021 ◽

pp. 305-312

Author(s):

Arun Prasath Kanagaraj ◽

Amuthakkannan Pandian ◽

Veerasimman Arumugaprabu ◽

Rajendran Deepak Joel Johnson ◽

Vigneswaran Shanmugam ◽

...

Keyword(s):

Mechanical Behavior ◽

Polymer Composites ◽

Basalt Fiber ◽

Dynamic Mechanical ◽

Dynamic Mechanical Behavior

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Right Heart Structure, Geometry and Function Assessed by Echocardiography in 6-Year-Old Children Born Extremely Preterm—A Population-Based Cohort Study

Journal of Clinical Medicine ◽

10.3390/jcm10010122 ◽

2020 ◽

Vol 10 (1) ◽

pp. 122

Author(s):

Lilly-Ann Mohlkert ◽

Jenny Hallberg ◽

Olof Broberg ◽

Gunnar Sjöberg ◽

Annika Rydberg ◽

...

Keyword(s):

Preterm Birth ◽

Ductus Arteriosus ◽

Population Based ◽

Right Heart ◽

Functional Changes ◽

Cardiac Phenotype ◽

Extremely Preterm ◽

Healthy Control ◽

The Right ◽

And Function

Preterm birth has been associated with altered cardiac phenotype in adults. Our aim was to test the hypothesis that children surviving extremely preterm birth have important structural or functional changes of the right heart or pulmonary circulation. We also examined relations between birth size, gestational age, neonatal diagnoses of bronchopulmonary dysplasia (BPD) and patent ductus arteriosus (PDA) with cardiac outcomes. We assessed a population-based cohort of children born in Sweden before 27 weeks of gestation with echocardiography at 6.5 years of age (n = 176). Each preterm child was matched to a healthy control child born at term. Children born preterm had significantly smaller right atria, right ventricles with smaller widths, higher relative wall thickness and higher estimated pulmonary vascular resistance (PVR) than controls. In preterm children, PVR and right ventricular myocardial performance index (RVmpi’) were significantly higher in those with a PDA as neonates than in those without PDA, but no such associations were found with BPD. In conclusion, children born extremely preterm exhibit higher estimated PVR, altered right heart structure and function compared with children born at term.

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Butyrate Prevents TGF-β1-Induced Alveolar Myofibroblast Differentiation and Modulates Energy Metabolism

Metabolites ◽

10.3390/metabo11050258 ◽

2021 ◽

Vol 11 (5) ◽

pp. 258

Author(s):

Hyo Yeong Lee ◽

Somi Nam ◽

Mi Jeong Kim ◽

Su Jung Kim ◽

Sung Hoon Back ◽

...

Keyword(s):

Energy Metabolism ◽

Pulmonary Fibrosis ◽

Transforming Growth Factor ◽

Mitochondrial Dynamics ◽

Tca Cycle ◽

Lung Fibroblasts ◽

Myofibroblast Differentiation ◽

Pulmonary Fibroblasts ◽

Matrix Deposition ◽

Tgf Β1

Idiopathic pulmonary fibrosis (IPF) is a serious lung disease characterized by excessive collagen matrix deposition and extracellular remodeling. Signaling pathways mediated by fibrotic cytokine transforming growth factor β1 (TGF-β1) make important contributions to pulmonary fibrosis, but it remains unclear how TGF-β1 alters metabolism and modulates the activation and differentiation of pulmonary fibroblasts. We found that TGF-β1 lowers NADH and NADH/NAD levels, possibly due to changes in the TCA cycle, resulting in reductions in the ATP level and oxidative phosphorylation in pulmonary fibroblasts. In addition, we showed that butyrate (C4), a short chain fatty acid (SCFA), exhibits potent antifibrotic activity by inhibiting expression of fibrosis markers. Butyrate treatment inhibited mitochondrial elongation in TGF-β1-treated lung fibroblasts and increased the mitochondrial membrane potential (MMP). Consistent with the mitochondrial observations, butyrate significantly increased ADP, ATP, NADH, and NADH/NAD levels in TGF-β1-treated pulmonary fibroblasts. Collectively, our findings indicate that TGF-β1 induces changes in mitochondrial dynamics and energy metabolism during myofibroblast differentiation, and that these changes can be modulated by butyrate, which enhances mitochondrial function.

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