Age-related changes in collagen gel contraction by cultured human lung fibroblasts resulting in cross-over of contraction curves between young and aged cells

AbstractMany lung diseases are characterized by fibrosis, leading to impaired tissue patency and reduced lung function. Development of fibrotic tissue depends on two-way interaction between the cells and the extra-cellular matrix (ECM). Concentration-dependent increased stiffening of the ECM is sensed by the cells, which in turn increases intracellular contraction and pulling on the matrix causing matrix reorganization and further stiffening. It is generally accepted that the inflammatory cytokine growth factor β1 (TGF-β1) is a major driver of lung fibrosis through the stimulation of ECM production. However, TGF-β1 also regulates the expression of members of the tropomyosin (Tm) family of actin associating proteins that mediate ECM reorganization through intracellular-generated forces. Thus, TGF-β1 may mediate the bi-directional signaling between cells and the ECM that promotes tissue fibrosis. Using combinations of cytokine stimulation, mRNA, protein profiling and cellular contractility assays with human lung fibroblasts, we show that concomitant induction of key Tm isoforms and ECM by TGF-β1, significantly accelerates fibrotic phenotypes. Knocking down Tpm2.1 reduces fibroblast-mediated collagen gel contraction. Collectively, the data suggest combined ECM secretion and actin cytoskeleton contractility primes the tissue for enhanced fibrosis. Our study suggests that Tms are at the nexus of inflammation and tissue stiffening. Small molecules targeting specific Tm isoforms have recently been designed; thus targeting Tpm2.1 may represent a novel therapeutic target in lung fibrosis.

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Vitamin D Augments Collagen Gel Contraction Mediated By Human Lung Fibroblasts

10.1164/ajrccm-conference.2012.185.1_meetingabstracts.a1919 ◽

2012 ◽

Author(s):

Xiangde Liu ◽

Amy Nelson ◽

Xingqi Wang ◽

Maha Farid ◽

Yoko Gunji ◽

...

Keyword(s):

Vitamin D ◽

Human Lung ◽

Collagen Gel ◽

Lung Fibroblasts ◽

Human Lung Fibroblasts ◽

Collagen Gel Contraction

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Red blood cells increase secretion of matrix metalloproteinases from human lung fibroblasts in vitro

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00057.2005 ◽

2006 ◽

Vol 290 (2) ◽

pp. L326-L333 ◽

Cited By ~ 20

Author(s):

K. Fredriksson ◽

X. D. Liu ◽

J. Lundahl ◽

J. Klominek ◽

S. I. Rennard ◽

...

Keyword(s):

Western Blot ◽

Human Lung ◽

Active Form ◽

Collagen Gel ◽

Gelatin Zymography ◽

Lung Fibroblasts ◽

Tissue Inhibitors Of Metalloproteinases ◽

Collagen Gels ◽

Human Lung Fibroblasts ◽

Collagen Gel Contraction

Tissue remodeling is an important process in many inflammatory and fibrotic lung disorders. RBC may in these conditions interact with extracellular matrix (ECM). Fibroblasts can produce and secrete matrix components, matrix-degrading enzymes (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). Imbalance in matrix synthesis/degradation may result in rearrangement of tissue architecture and lead to diseases such as emphysema or fibrosis. Neutrophil elastase (NE), a protease released by neutrophils, is known to activate MMP. We hypothesized that RBC can stimulate secretion of MMPs from human lung fibroblasts and that NE can augment this effect. Human fetal lung fibroblasts were cultured in floating collagen gels with or without RBC. After 4 days, the culture medium was analyzed with gelatin zymography, Western blot, and ELISA for MMP-1, -2, -3 and TIMP-1, -2. RBC augmented NE-induced fibroblast-mediated collagen gel contraction compared with NE alone (18.4 ± 1.6%, 23.7 ± 1.4% of initial gel area, respectively). A pan-MMP inhibitor (GM-6001) completely abolished the stimulating effect of NE. Gelatin zymography showed that RBC stimulated MMP-2 activity and that NE enhanced conversion to the active form. Addition of GM-6001 completely inhibited MMP-2 activity in controls, whereas it only partially altered RBC-induced MMP activity. Western blot confirmed the presence of MMP-1 and MMP-3 in fibroblasts stimulated with RBC, and ELISA confirmed increased concentrations of pro-MMP-1. We conclude that stimulation of MMP secretion by fibroblasts may explain the ability of RBC to augment fibroblast-mediated collagen gel contraction. This might be a potential mechanism by which hemorrhage in inflammatory conditions leads to ECM remodeling.

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Fibronectin production by cultured human lung fibroblasts in three-dimensional collagen gel culture

In Vitro Cellular & Developmental Biology - Animal ◽

10.1007/s11626-998-0125-7 ◽

1998 ◽

Vol 34 (3) ◽

pp. 203-210 ◽

Cited By ~ 27

Author(s):

Yuichi Adachi ◽

Tadashi Mio ◽

Keiichi Takigawa ◽

Ilja Striz ◽

Debra J. Romberger ◽

...

Keyword(s):

Human Lung ◽

Three Dimensional ◽

Collagen Gel ◽

Lung Fibroblasts ◽

Human Lung Fibroblasts ◽

Collagen Gel Culture ◽

Gel Culture

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PGE2Desensitizesβ-Agonist Effect on Human Lung Fibroblast-Mediated Collagen Gel Contraction through Upregulating PDE4

Mediators of Inflammation ◽

10.1155/2013/145197 ◽

2013 ◽

Vol 2013 ◽

pp. 1-9 ◽

Cited By ~ 1

Author(s):

Qiuhong Fang ◽

Yingmin Ma ◽

Jing Wang ◽

Joel Michalski ◽

Stephen I. Rennard ◽

...

Keyword(s):

Human Lung ◽

Collagen Gel ◽

Inhibitory Effect ◽

Lung Fibroblast ◽

Lung Fibroblasts ◽

Pde4 Inhibitor ◽

Dependent Manner ◽

Human Lung Fibroblast ◽

Collagen Gel Contraction ◽

Long Acting

In the current study, we investigated the effect of a long-actingβ-agonist (salmeterol) and a phosphodiesterase 4 (PDE4) inhibitor (cilomilast) on human lung fibroblast-mediated collagen gel contraction. Higher concentrations of salmeterol (10−7and 10−6 M) inhibited fibroblast-mediated collagen gel contraction. No effect was observed with cilomilast alone (up to 10−5 M). In the presence of 10−8 M salmeterol, however, cilomilast could significantly inhibit fibroblast-mediated collagen gel contraction in a concentration-dependent manner (10−7~10−5 M). Blockade of endogenous PGE2by indomethacin further potentiated the inhibitory effect of salmeterol on fibroblast-mediated collagen gel contraction, but it did not affect cilomilast's effect. Pretreatment with PGE2abolished the inhibitory effect of salmeterol, but it potentiated the inhibitory effect of cilomilast on fibroblast-mediated collagen gel contraction. Finally, indomethacin slightly inhibited PDE4C expression, while PGE2stimulated the expression of PDE4A and -4C in human lung fibroblasts. These findings suggest that long-actingβ-agonist and PDE4 inhibitor have a synergistic effect in regulating fibroblast tissue repair functions and that PGE2can modulate the effect ofβ-agonist and PDE4 inhibitor at least in part through the mechanism of regulating PDE4 expression.

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