Transforming growth factor-alpha enhances alveolar epithelial cell repair in a new in vitro model

1994 ◽  
Vol 267 (6) ◽  
pp. L728-L738 ◽  
Author(s):  
F. Kheradmand ◽  
H. G. Folkesson ◽  
L. Shum ◽  
R. Derynk ◽  
R. Pytela ◽  
...  

Alveolar epithelial type II cells are essential for regenerating an intact alveolar barrier after destruction of type I cells in vivo. The first objective of these experimental studies was to develop an in vitro model to quantify alveolar epithelial cell wound repair. The second objective was to investigate mechanisms of alveolar epithelial cell wound healing by studying the effects of serum and transforming growth factor-alpha (TGF-alpha) on wound closure. Primary cultures of rat alveolar type II cells were prepared by standard methods and grown to form confluent monolayers in 48 h. Then a wound was made by denuding an area (mean initial area of 2.1 +/- 0.6 mm2) of the monolayer. Re-epithelialization of the denuded area over time in the presence or absence of serum was measured using quantitative measurements from time-lapse video microscopy. The half time of wound healing was significantly enhanced in the presence of serum compared with serum-free conditions (2.4 +/- 0.2 vs. 17.4 +/- 0.8 h, P < 0.001). We then tested the hypothesis that TGF-alpha is an important growth factor for stimulating wound repair of alveolar epithelial cells. Exogenous addition of TGF-alpha in serum-free medium resulted in a significantly more rapid wound closure, and, furthermore, the addition of a monoclonal antibody to TGF-alpha in the presence of serum significantly decreased fourfold the rate of wound closure. Measurement of internuclear cell distance confirmed that both cell motility and cell spreading were responsible for closure of the wound. These data demonstrate that 1) the mechanisms of alveolar cell repair can be studied in vitro and that 2) TGF-alpha is a potent growth factor that enhances in vitro alveolar epithelial cell wound closure.

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257281
Author(s):  
Silvia Speca ◽  
Caroline Dubuquoy ◽  
Christel Rousseaux ◽  
Philippe Chavatte ◽  
Pierre Desreumaux ◽  
...  

The development of more effective, better tolerated drug treatments for progressive pulmonary fibrosis (of which idiopathic pulmonary fibrosis is the most common and severe form) is a research priority. The peroxisome proliferator-activated receptor gamma (PPAR-γ) is a key regulator of inflammation and fibrosis and therefore represents a potential therapeutic target. However, the use of synthetic PPAR-γ agonists may be limited by their potentially severe adverse effects. In a mouse model of bleomycin (BLM)-induced pulmonary fibrosis, we have demonstrated that the non-racemic selective PPAR-γ modulator GED-0507 is able to reduce body weight loss, ameliorate clinical and histological features of pulmonary fibrosis, and increase survival rate without any safety concerns. Here, we focused on the biomolecular effects of GED-0507 on various inflammatory/fibrotic pathways. We demonstrated that preventive and therapeutic administration of GED-0507 reduced the BLM-induced mRNA expression of several markers of fibrosis, including transforming growth factor (TGF)-β, alpha-smooth muscle actin, collagen and fibronectin as well as epithelial-to-mesenchymal transition (EMT) and expression of mucin 5B. The beneficial effect of GED-0507 on pulmonary fibrosis was confirmed in vitro by its ability to control TGFβ-induced myofibroblast activation in the A549 human alveolar epithelial cell line, the MRC-5 lung fibroblast line, and primary human lung fibroblasts. Compared with the US Food and Drug Administration-approved antifibrotic drugs pirfenidone and nintedanib, GED-0507 displayed greater antifibrotic activity by controlling alveolar epithelial cell dysfunction, EMT, and extracellular matrix remodeling. In conclusion, GED-0507 demonstrated potent antifibrotic properties and might be a promising drug candidate for the treatment of pulmonary fibrosis.


2000 ◽  
Vol 279 (6) ◽  
pp. L1184-L1190 ◽  
Author(s):  
Thomas Geiser ◽  
Pierre-Henri Jarreau ◽  
Kamran Atabai ◽  
Michael A. Matthay

Biologically active interleukin (IL)-1β is present in the pulmonary edema fluid obtained from patients with acute lung injury and has been implicated as an important early mediator of nonpulmonary epithelial wound repair. Therefore, we tested the hypothesis that IL-1β would enhance wound repair in cultured monolayers from rat alveolar epithelial type II cells. IL-1β (20 ng/ml) increased the rate of in vitro alveolar epithelial repair by 118 ± 11% compared with that in serum-free medium control cells ( P < 0.01). IL-1β induced cell spreading and migration at the edge of the wound but not proliferation. Neutralizing antibodies to epidermal growth factor (EGF) and transforming growth factor-α or inhibition of the EGF receptor by tyrphostin AG-1478 or genistein inhibited IL-1β-induced alveolar epithelial repair, indicating that IL-1β enhances in vitro alveolar epithelial repair by an EGF- or transforming growth factor-α-dependent mechanism. Moreover, the mitogen-activated protein kinase pathway is involved in IL-1β-induced alveolar epithelial repair because inhibition of extracellular signal-regulated kinase activation by PD-98059 inhibited IL-1β-induced alveolar epithelial repair. In conclusion, IL-1β augments in vitro alveolar epithelial repair, indicating a possible novel role for IL-1β in the early repair process of the alveolar epithelium in acute lung injury.


1994 ◽  
Vol 266 (1) ◽  
pp. L17-L22 ◽  
Author(s):  
R. M. Ryan ◽  
M. M. Mineo-Kuhn ◽  
C. M. Kramer ◽  
J. N. Finkelstein

The type II alveolar epithelial cell plays a critical role in the repair of lung injury by repopulating the entire damaged alveolar epithelium. We report our studies of the effects of known growth factors on the in vitro proliferation of isolated neonatal rabbit type II cells. Transforming growth factor-alpha (TGF-alpha) and epidermal growth factor (EGF) increased [3H]thymidine incorporation, cell number, and labeling index above control. Transforming growth factor-beta (TGF-beta) decreased [3H]thymidine incorporation, cell number, and labeling index compared with control. When added simultaneously, TGF-beta blocked the stimulatory effect of TGF-alpha or EGF. If TGF-alpha is added before TGF-beta, the ability of TGF-beta to block the mitogenic effect of TGF-alpha was diminished the later in time TGF-beta was added. If TGF-beta was added first, later addition of TGF-alpha had no effect. The current work demonstrates that specific growth factors, including some known to be produced by other lung cells, alter the proliferation in vitro of isolated neonatal rabbit type II alveolar epithelial cells.


1997 ◽  
Vol 272 (2) ◽  
pp. F222-F228
Author(s):  
C. Kjelsberg ◽  
H. Sakurai ◽  
K. Spokes ◽  
C. Birchmeier ◽  
I. Drummond ◽  
...  

The growth factor/receptor combination of hepatocyte growth factor (HGF)/c-met has been postulated to be critical for mesenchymal-to-epithelial conversion and tubule formation in the developing kidney. We therefore isolated and immortalized cells from embryonic kidneys of met -/- transgenic mice to determine whether these cells were epithelial and able to chemotax and form tubules in vitro. The cells were immortalized with retrovirus expressing human papillomavirus 16 (HPV 16) E6/E7 genes. Two rapidly dividing clones were isolated and found to express the epithelial cell markers cytokeratin, zonula occludens-1, and E-cadherin but not to express the fibroblast marker vimentin. The met -/- cells were able to chemotax in response to epidermal growth factor and transforming growth factor-alpha (TGF-alpha) and form tubules in vitro in response to TGF-alpha but not HGF. These experiments suggest that the HGF/c-met axis is not essential for epithelial cell development in the embryonic kidney and demonstrate that other growth factors are capable of supporting early tubulogenesis.


2005 ◽  
Vol 31 (5) ◽  
pp. 461-482 ◽  
Author(s):  
Colin E. Olsen ◽  
Brant E. Isakson ◽  
Gregory J. Seedorf ◽  
Richard L. Lubman ◽  
Scott Boitano

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