Extracellular matrix deposition by primary human lung fibroblasts in response to TGF-β1 and TGF-β3

1999 ◽  
Vol 276 (5) ◽  
pp. L814-L824 ◽  
Author(s):  
Oliver Eickelberg ◽  
Eleonore Köhler ◽  
Frank Reichenberger ◽  
Sybille Bertschin ◽  
Thomas Woodtli ◽  
...  

Increased collagen and extracellular matrix (ECM) deposition within the lung is a characteristic feature of lung fibrosis. Transforming growth factor (TGF)-β isoforms play a pivotal role in the production of collagen and ECM. In this study, we investigated the effects of TGF-β1 and TGF-β3 on the main processes controlling ECM deposition using primary human lung fibroblasts. We analyzed 1) collagen metabolism by [3H]proline incorporation, 2) matrix metalloproteinase (MMP) expression by substrate gel zymography, and 3) tissue inhibitor of metalloproteinases (TIMP) expression by Western blot analysis. TGF-β1 and TGF-β3 increased the percentage of secreted collagens in supernatants of primary fibroblasts from 8.0 ± 1.2 (control) to 23.6 ± 4.6 and 22.3 ± 1.3%, respectively. The collagen percentage in deposited ECM was increased from 5.8 ± 0.3 (control) to 9.0 ± 0.5 and 8.8 ± 0.5% by TGF-β1 and TGF-β3, respectively. Secretion of MMP-1 (interstitial collagenase) by fibroblasts was reduced by both TGF-β isoforms, whereas secretion of MMP-2 (gelatinase A) was unaffected by either of the two isoforms. Both TGF-β isoforms increased TIMP-1 protein expression, whereas TIMP-2 protein was decreased. We thus conclude that TGF-β1 and TGF-β3 are equally potent in increasing ECM deposition. Their fibrotic effect in lung fibroblasts results from 1) an increase in the secretion and deposition of total ECM and collagens, 2) a decrease in MMP-1 secretion, and 3) an increase of TIMP-1 expression.

Author(s):  
Mary T. Doolin ◽  
Ian M. Smith ◽  
Kimberly M. Stroka

Idiopathic pulmonary fibrosis (IPF) is a chronic disease of the lung caused by a rampant inflammatory response that results in the deposition of excessive extracellular matrix (ECM). IPF patient lungs also develop fibroblastic foci that consist of activated fibroblasts and myofibroblasts. In concert with ECM deposition, the increased cell density within fibroblastic foci imposes confining forces on lung fibroblasts. In this work, we observed that increased cell density increases the incidence of fibroblast to myofibroblast transition (FMT), but mechanical confinement imposed by micropillars has no effect on FMT incidence. We found that human lung fibroblasts (HLFs) express more α-SMA and deposit more collagen matrix, which are both characteristics of myofibroblasts, in response to TGF-β1 when cells were seeded at a high density compared to a medium or a low density. These results support the hypothesis that HLFs undergo FMT more readily in response to TGF-β1 when cells are densely packed, and this effect could be dependent on increased OB-cadherin expression. This work demonstrates that cell density is an important factor to consider when modelling IPF in vitro, and it may suggest decreasing cell density within fibroblastic foci as a strategy to reduce IPF burden.


Metabolites ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 258
Author(s):  
Hyo Yeong Lee ◽  
Somi Nam ◽  
Mi Jeong Kim ◽  
Su Jung Kim ◽  
Sung Hoon Back ◽  
...  

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.


2015 ◽  
Vol 309 (8) ◽  
pp. L821-L833 ◽  
Author(s):  
Anurag Mishra ◽  
Todd A. Stueckle ◽  
Robert R. Mercer ◽  
Raymond Derk ◽  
Yon Rojanasakul ◽  
...  

Carbon nanotubes (CNTs) induce rapid interstitial lung fibrosis, but the underlying mechanisms are unclear. Previous studies indicated that the ability of CNTs to penetrate lung epithelium, enter interstitial tissue, and stimulate fibroblasts to produce collagen matrix is important to lung fibrosis. In this study, we investigated the activation of transforming growth factor-β receptor-1 [TGF-β R1; i.e., activin receptor-like kinase 5 (ALK5) receptor] and TGF-β/Smad signaling pathway in CNT-induced collagen production in human lung fibroblasts. Human lung fibroblasts and epithelial cells were exposed to low, physiologically relevant concentrations (0.02–0.6 μg/cm2) of single-walled CNTs (SWCNT) and multiwalled CNTs (MWCNT) in culture and analyzed for collagen, TGF-β1, TGF-β R1, and SMAD proteins by Western blotting and immunofluorescence. Chemical inhibition of ALK5 and short-hairpin (sh) RNA targeting of TGF-β R1 and Smad2 were used to probe the fibrogenic mechanism of CNTs. Both SWCNT and MWCNT induced an overexpression of TGF-β1, TGF-β R1 and Smad2/3 proteins in lung fibroblasts compared with vehicle or ultrafine carbon black-exposed controls. SWCNT- and MWCNT-induced collagen production was blocked by ALK5 inhibitor or shRNA knockdown of TGF-β R1 and Smad2. Our results indicate the critical role of TGF-β R1/Smad2/3 signaling in CNT-induced fibrogenesis by upregulating collagen production in lung fibroblasts. This novel finding may aid in the design of mechanism-based risk assessment and development of rapid screening tests for nanomaterial fibrogenicity.


1969 ◽  
Vol 41 (1) ◽  
pp. 298-311 ◽  
Author(s):  
Tom Elsdale ◽  
Robert Foley

Randomly seeded Petri dish cultures of embryonic human lung fibroblasts generate, in the course of their growth, highly ordered cellular arrangements. Thick, bilaterally symmetrical ridges with an axial polarity and an orthogonal, multilayered internal organization are observed within stationary cultures. The generation of these structures has been investigated. Ridges result from the spontaneous aggregation of cells in postconfluent cultures brought about by directed cell movements. These movements are promoted by the localized production of extracellular matrix sheets containing collagen, which provide new substrates for cellular colonization. Cells that have colonized one matrix substrate may secrete another above themselves, which will in turn be colonized. By a continuation of this cycle, thick stacks consisting of alternate layers of cells and matrix are produced to yield the observed aggregations. The distribution and shape of ridges in a culture imply that matrix substrates are confined to specific locations. The suggested control hypothesis assumes that all the cells in fibroblast cultures are potential producers of a single species of matrix. The serviceability of this matrix as a substrate for cellular colonization, however, is destroyed if the producer cells are motile. Matrix substrates, therefore, are only made by nonmotile cells.


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