Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0034069 (pulmonary fibrosis)
 7,050 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Activin A is a homodimeric protein structurally and functionally related to transforming growth factor beta (TGF-beta), and the expression of activin A is modulated by TGF-beta. Here, we demonstrate the expression of activin A in normal and bleomycin (BLM)-treated murine lungs. ICR mice were treated with BLM intraperitoneally for 10 days, whereas saline vehicle was injected into control mice. Intra-alveolar fibrotic changes were observed in the lung tissue obtained from the mice at day 14 after the final BLM administration. Immunohistochemical studies using a polyclonal antibody to activin A revealed the presence of activin A in the bronchiolar epithelium and smooth muscle cells of veins in both control and BLM-treated mice. In the BLM-treated mice at days 7 and 14, the marked infiltration of immunoreactive alveolar macrophages was observed in the area of fibrotic changes. Bioactivity of activin A measured by erythroid differentiation factor assay in the conditioned medium of alveolar macrophages obtained from BLM-treated mice at day 14 was significantly increased. These findings indicate that alveolar macrophages are a potent source of activin A after BLM treatment. The present study demonstrates for the first time the abundant expression of activin A in murine lung tissues after BLM administration, suggesting that activin A may play a role in the pathogenesis of BLM-induced pulmonary fibrosis.
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PMID:Expression of immunoreactive and bioactive activin A protein in adult murine lung after bleomycin treatment. 754 Dec 20

The expression of activin A, one of the transforming growth factor-beta supergene family, was studied in various pulmonary conditions associated with interstitial pulmonary fibrosis (3 cases with diffuse alveolar damage, 6 cases with idiopathic pulmonary fibrosis, and 1 case with pulmonary fibrosis associated with rheumatoid arthritis) using immunohistochemical techniques on paraffin-embedded sections. Controls consisted of 10 cases with normal pulmonary parenchyma, and 2 cases with primary pulmonary hypertension and 1 case with secondary pulmonary hypertension were also studied. The lung specimens from normal parenchyma weakly expressed immunoreactive activin A on the bronchiolar epithelium. In marked contrast, all of the specimens from cases with diffuse alveolar damage and interstitial pulmonary fibrosis demonstrated strong expression of activin A on metaplastic epithelium, hyperplastic smooth muscle cells, desquamated cells, and alveolar macrophages. Pulmonary arteries from patients with primary or secondary pulmonary hypertension showed abundant immunoreactive activin A on smooth muscle cells. These findings suggest a potential role for this growth factor, activin A, in the pathogenesis of pulmonary tissue remodeling associated with interstitial pulmonary fibrosis.
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PMID:Expression of immunoreactive activin A protein in remodeling lesions associated with interstitial pulmonary fibrosis. 877 26

An increase in fibroblasts and associated connective tissue is a feature of pulmonary fibrosis. Activin A belongs to the transforming growth factor-beta (TGF-beta) supergene family and is known to have important roles in the induction of mesoderm and differentiation processes during development in early embryogenesis. It also modifies the growth and differentiation of various target cells. In this study we determined whether activin A could modulate human lung fibroblast (HFL1) activity, particularly with respect to proliferation and its differentiation into myofibroblast. A maximal effect on cell proliferation was observed at a low concentration of activin A (10(-11) M), and the effect of activin A was abolished by follistatin, an activin-binding protein. Activin A stimulated differentiation of HFL1 into myofibroblast in a dose-dependent manner. Thus activin A has potential effects on proliferation of lung fibroblast and its differentiation into myofibroblast, and may contribute to structural remodeling observed in pulmonary fibrosis.
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PMID:Effects of activin A on proliferation and differentiation of human lung fibroblasts. 892 Sep 25

Growth factors are known not only to cause a mitogenic response and alter differentiated characteristics of the target cells, but also to play important roles in intercellular signaling. Many growth factors are expressed in the embryonic and regulate embryogenesis. Pulmonary fibrosis is characterized by a complex process involving chronic inflammatory reaction, fibroblast proliferation, and abnormal deposition of interstitial collagen as a result of excess healing reaction. In the early phases, TNF-alpha, IL-beta and GM-CSF secreted by alveolar macrophages regulate and enhance pulmonary inflammation. On the contrary, TGF-alpha, KGF and HGF have been reported to enhance repair of alveolar epithelium and vascular endothelium in the injured lung. Furthermore, growth factors produced by alveolar macrophages and epithelium, such as PDGF, TGF-beta and activin A and belongs to the TGF-beta supergene family are known to play cardinal roles in fibroblast proliferation and pulmonary fibrosis. Further works concerning this complex growth factors (cytokines) network are required to provide a basis of the pathophysiology of pulmonary fibrosis.
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PMID:[Growth factors in the process of inflammation and fibrosis in the lung]. 974 56

Activin A is a member of the transforming growth factor-beta superfamily that exerts its diverse biological effects through bindings to activin specific transmembrane serine/threonine kinase receptors. The fibroblast-mediated contraction of a collagen gel is thought to be a model of part of the wound-repair response and tissue contraction. In this study, we found the expression of activin type I receptors (ActR-I and ActR-IB) and type II receptor (ActR-II) on human fetal lung fibroblasts (HFL-1) by RT-PCR and immunocytochemistry. We also examined the effects of activin A on the HFL-1-mediated collagen gel contraction. Activin A stimulated collagen gel contraction in a dose dependent manner and its effect was abolished by an activin-binding protein, follistatin, that specifically suppresses activin A activities. This study demonstrated that ActR-I, ActR-1B and ActR-II are expressed on human fetal lung fibroblast and that activin A regulates fibroblast-mediated collagen gel contraction, suggesting that activin A might contribute to human lung fibroblast activities and structural remodeling observed in pulmonary fibrosis.
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PMID:Activin receptors are expressed on human lung fibroblast and activin A facilitates fibroblast-mediated collagen gel contraction. 1126 90