transforming-growth-factor-beta and Emphysema

Fibrogenic lung reactions occur as a common phenotype shared among disorders of heterogeneous etiologies. Even with a common etiology, the extent and pattern of fibrosis vary greatly among individuals, even within families, suggesting complex gene-environment interactions. The search for mechanisms shared among all fibrotic lung diseases would represent a major advance in the identification of therapeutic targets that could have a broad impact on lung health. Although it is difficult to grasp all of the complexities of the varied cell types and cytokine networks involved in lung fibrogenic responses, and to predict the biologic responses to the overexpression or deficiency of individual cytokines, a large body of evidence converges on a single common theme: the central importance of the transforming growth factor beta (TGF-beta) pathway. Therapies that act upstream or downstream of TGF-beta activation have the therapeutic potential to treat all fibrogenic responses in the lung.

Topics: Asthma; Emphysema; Fibroblasts; Humans; Lung Diseases; Pulmonary Disease, Chronic Obstructive; Pulmonary Fibrosis; Transforming Growth Factor beta

The transforming growth factor (TGF)-beta superfamily of secreted growth factors consists of more than 40 members, including the TGF-beta isoforms themselves, bone morphogenetic proteins, and activins. Most of these factors have been shown to be essential for proper organ development, a process often recapitulated in chronic diseases. Importantly, TGF-beta superfamily members are key regulators of extracellular matrix composition and alveolar epithelial cell and fibroblast function in the lung. Both during lung development and disease, TGF-betas therefore control lung homeostasis by providing the structural requirements and functional micromilieu needed for physiological epithelial cell function and proper gas exchange. Prolonged alterations of TGF-beta signaling have been shown to result in structural changes in the lung that compromise gas exchange and lung function, as seen in arrested lung development, a feature of bronchopulmonary dysplasia, lung fibrosis, and chronic obstructive pulmonary disease. All these syndromes share a loss of functional alveolar structures, which ultimately leads to a decreased life expectancy. In this review, we cover our current understanding of the impact of TGF-beta signaling on chronic lung disease. We focus on distorted TGF-beta signaling in bronchopulmonary dysplasia and chronic obstructive pulmonary disease as prototype diseases of the premature and matured lung, respectively, which are both characterized by functional and structural loss of alveolar units.

Topics: Bronchopulmonary Dysplasia; Emphysema; Humans; Infant, Newborn; Pulmonary Alveoli; Pulmonary Disease, Chronic Obstructive; Signal Transduction; Transforming Growth Factor beta

Heterotrimeric guanine nucleotide-binding protein (G protein) signaling links hundreds of G protein-coupled receptors with four G protein signaling pathways. Two of these, one mediated by G

Topics: Animals; Emphysema; GTP-Binding Protein alpha Subunits, Gq-G11; Interleukin-33; Macrophages, Alveolar; Matrix Metalloproteinase 12; Mice; Mice, Transgenic; Respiratory Mucosa; Signal Transduction; Transforming Growth Factor beta; Ventilator-Induced Lung Injury

Progressive pulmonary inflammation and emphysema have been implicated in the progression of chronic obstructive pulmonary disease (COPD), while current pharmacological treatments are not effective. Transplantation of bone marrow mesenchymal stem cells (MSCs) has been identified as one such possible strategy for treatment of lung diseases including acute lung injury (ALI) and pulmonary fibrosis. However, their role in COPD still requires further investigation. The aim of this study is to test the effect of administration of rat MSCs (rMSCs) on emphysema and pulmonary function. To accomplish this study, the rats were exposed to cigarette smoke (CS) for 11 weeks, followed by administration of rMSCs into the lungs. Here we show that rMSCs infusion mediates a down-regulation of pro-inflammatory mediators (TNF-α, IL-1β, MCP-1, and IL-6) and proteases (MMP9 and MMP12) in lung, an up-regulation of vascular endothelial growth factor (VEGF), VEGF receptor 2, and transforming growth factor (TGFβ-1), while reducing pulmonary cell apoptosis. More importantly, rMSCs administration improves emphysema and destructive pulmonary function induced by CS exposure. In vitro co-culture system study of human umbilical endothelial vein cells (EA.hy926) and human MSCs (hMSCs) provides the evidence that hMSCs mediates an anti-apoptosis effect, which partly depends on an up-regulation of VEGF. These findings suggest that MSCs have a therapeutic potential in emphysematous rats by suppressing the inflammatory response, excessive protease expression, and cell apoptosis, as well as up-regulating VEGF, VEGF receptor 2, and TGFβ-1.

Topics: Animals; Disease Models, Animal; Emphysema; Gene Expression Regulation; Humans; Lung Injury; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Pneumonia; Pulmonary Disease, Chronic Obstructive; Rats; Receptors, Vascular Endothelial Growth Factor; Smoking; Tobacco Products; Transforming Growth Factor beta; Vascular Endothelial Growth Factor A

Transforming growth factor β (TGF-β) regulates inflammation, immunosuppression, and wound-healing cascades, but it remains unclear whether any of these functions involve regulation of myeloid cell function. The present study demonstrates that selective deletion of TGF-βRII expression in myeloid phagocytes i) impairs macrophage-mediated suppressor activity, ii) increases baseline mRNA expression of proinflammatory chemokines/cytokines in the lung, and iii) enhances type 2 immunity against the hookworm parasite Nippostrongylus brasiliensis. Strikingly, TGF-β-responsive myeloid cells promote repair of hookworm-damaged lung tissue, because LysM(Cre)TGF-βRII(flox/flox) mice develop emphysema more rapidly than wild-type littermate controls. Emphysematous pathology in LysM(Cre)TGF-βRII(flox/flox) mice is characterized by excessive matrix metalloprotease (MMP) activity, reduced lung elasticity, increased total lung capacity, and dysregulated respiration. Thus, TGF-β effects on myeloid cells suppress helminth immunity as a consequence of restoring lung function after infection.

Topics: Animals; Bone Marrow Cells; Emphysema; Hookworm Infections; Immunity; Lung; Lymphocyte Activation; Macrophages, Alveolar; Matrix Metalloproteinases; Mice; Mice, Inbred C57BL; Mice, Knockout; Myeloid Cells; Nippostrongylus; Pneumonia; Protein Serine-Threonine Kinases; Pulmonary Fibrosis; Receptor, Transforming Growth Factor-beta Type II; Receptors, Transforming Growth Factor beta; T-Lymphocytes; Transforming Growth Factor beta; Wound Healing

Topics: Adrenergic beta-Antagonists; Angiotensin II Type 1 Receptor Blockers; Animals; Aortic Aneurysm; Clinical Trials as Topic; Disease Models, Animal; Emphysema; Fibrillins; Humans; Losartan; Marfan Syndrome; Mice; Microfilament Proteins; Mutation; Transforming Growth Factor beta

To define the factors that control the tissue effects of IL-4, we compared the effects of Tg IL-4 in Balb/c and C57BL/6 mice. In the former, IL-4 caused modest eosinophilic inflammation and mild airway fibrosis and did not shorten survival. In C57BL/6 mice, IL-4 caused profound eosinophilic inflammation, airway fibrosis, emphysematous alveolar destruction, and premature death. These differences could not be accounted for by changes in Th2 or Th1 cytokines, receptor components, STAT6 activation, MMPs, or cathepsins. In contrast, in C57BL/6 mice, alveolar remodeling was associated with decreased levels of tissue inhibitors of metalloproteinase 2, -3, and -4 and alpha1-antitrypsin, and fibrosis was associated with increased levels of total and bioactive TGF-beta1. Impressive differences in adenosine metabolism were also appreciated, with increased tissue adenosine levels and A(1), A(2B), and A(3) adenosine receptor expression and decreased adenosine deaminase (ADA) activity in C57BL/6 animals. Treatment with ADA also reduced the inflammation, fibrosis, and emphysematous destruction and improved the survival of C57BL/6 Tg animals. These studies demonstrate that genetic influences control IL-4 effector pathways in the murine lung. They also demonstrate that IL-4 has different effects on adenosine metabolism in Balb/c and C57BL/6 mice and that these differences contribute to the different responses that IL-4 induces in these inbred animals.

Topics: Adenosine; Animals; Emphysema; Female; Fibrosis; Inflammation; Interleukin-4; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Pulmonary Alveoli; Rats; Species Specificity; Transforming Growth Factor beta; Transforming Growth Factor beta1

Marfan syndrome is an autosomal dominant disorder of connective tissue caused by mutations in fibrillin-1 (encoded by FBN1 in humans and Fbn1 in mice), a matrix component of extracellular microfibrils. A distinct subgroup of individuals with Marfan syndrome have distal airspace enlargement, historically described as emphysema, which frequently results in spontaneous lung rupture (pneumothorax; refs. 1-3). To investigate the pathogenesis of genetically imposed emphysema, we analyzed the lung phenotype of mice deficient in fibrillin-1, an accepted model of Marfan syndrome. Lung abnormalities are evident in the immediate postnatal period and manifest as a developmental impairment of distal alveolar septation. Aged mice deficient in fibrillin-1 develop destructive emphysema consistent with the view that early developmental perturbations can predispose to late-onset, seemingly acquired phenotypes. We show that mice deficient in fibrillin-1 have marked dysregulation of transforming growth factor-beta (TGF-beta) activation and signaling, resulting in apoptosis in the developing lung. Perinatal antagonism of TGF-beta attenuates apoptosis and rescues alveolar septation in vivo. These data indicate that matrix sequestration of cytokines is crucial to their regulated activation and signaling and that perturbation of this function can contribute to the pathogenesis of disease.

Topics: Animals; Apoptosis; Disease Models, Animal; Emphysema; Extracellular Matrix; Fibrillin-1; Fibrillins; Humans; Lung; Marfan Syndrome; Mice; Mice, Knockout; Mice, Transgenic; Microfilament Proteins; Neutralization Tests; Phenotype; Transforming Growth Factor beta

To characterize the possible role of a dysregulated proliferative capacity of pulmonary fibroblasts in insufficient tissue repair in lungs from patients with pulmonary emphysema, the authors undertook in vitro proliferative studies with pulmonary fibroblasts obtained from lung tissue of patients with emphysema. A comparison was made with fibroblasts from control subjects. The authors determined the in vitro proliferative capacity of fibroblasts at basal culture conditions and after modulation with interleukin-1beta, interferon-gamma, transforming growth factor-beta(1), and basic fibroblast growth factor. Proliferative capacity was determined by measurement of 5-bromo-2-deoxyuridine (BrdU) incorporation. BrdU incorporation by fibroblast cultures from both groups was very similar. Fibroblast cultures from control subjects, however, incorporated more BrdU after incubation with interleukin-1beta than cultures from patients with emphysema (P<.05). On the other hand, transforming growth factor-beta(1) decreased incorporation of BrdU stronger in fibroblast cultures from control subjects than from patients with emphysema (P<.05). Thus, the proliferative capacity of fibroblast cultures isolated from lung tissue of patients with pulmonary emphysema is different from that of control subjects. Although the difference is small, it may be an essential contribution to the development of pulmonary emphysema that only occurs after repeated smoke-induced injury over many years of an individual's life.

Topics: Adolescent; Adult; Aged; Bromodeoxyuridine; Cell Division; Cells, Cultured; Emphysema; Female; Fibroblast Growth Factor 2; Fibroblasts; Humans; Interferon-gamma; Interleukin-1; Lung; Male; Middle Aged; Transforming Growth Factor beta; Transforming Growth Factor beta1