TGF-ß enhances deposition of perlecan from COPD airway smooth muscle.

Chronic obstructive pulmonary disease (COPD) and asthma are characterized by irreversible remodeling of the airway walls, including thickening of the airway smooth muscle layer. Perlecan is a large, multidomain, proteoglycan that is expressed in the lungs, and in other organ systems, and has been described to have a role in cell adhesion, angiogenesis, and proliferation. This study aimed to investigate functional properties of the different perlecan domains in relation to airway smooth muscle cells (ASMC). Primary human ASMC obtained from donors with asthma (n = 13), COPD (n = 12), or other lung disease (n = 20) were stimulated in vitro with 1 ng/ml transforming growth factor-ß(1) (TGF-ß(1)) before perlecan deposition and cytokine release were analyzed. In some experiments, inhibitors of signaling molecules were added. Perlecan domains I-V were seeded on tissue culture plates at 10 µg/ml with 1 µg/ml collagen I as a control. ASM was incubated on top of the peptides before being analyzed for attachment, proliferation, and wound healing. TGF-ß(1) upregulated deposition of perlecan by ASMC from COPD subjects only. TGF-ß(1) upregulated release of IL-6 into the supernatant of ASMC from all subjects. Inhibitors of SMAD and JNK signaling molecules decreased TGF-ß(1)-induced perlecan deposition by COPD ASMC. Attachment of COPD ASMC was upregulated by collagen I and perlecan domains IV and V, while perlecan domain II upregulated attachment only of asthmatic ASMC. Seeding on perlecan domains did not increase proliferation of any ASMC type. TGF-ß(1)-induced perlecan deposition may enhance attachment of migrating ASMC in vivo and thus may be a mechanism for ASMC layer hypertrophy in COPD.

Matrix proteins from smoke-exposed fibroblasts are pro-proliferative.

Airway remodeling decreases lung function in chronic obstructive pulmonary disease (COPD). Extracellular matrix (ECM) deposition is increased in remodeled airways and drives cellular processes of proliferation, migration, and inflammation. We investigated the role of cigarette smoke in altering the ECM deposited from human lung fibroblasts. Lung fibroblasts isolated from patients with COPD or other lung disease were exposed to cigarette smoke extract (CSE) and 5 ng/ml transforming growth factor-ß1 for 72 hours; in some experiments, inhibitors of signaling molecules were added. Deposition of perlecan, fibronectin, and elastin were measured by ELISA, as was release of IL-8 and IL-13. Unstimulated fibroblast cells were reseeded onto deposited matrix and assessed for proliferation and cytokine release. CSE (5%) increased deposition of fibronectin and perlecan from only COPD fibroblasts. Fibronectin and perlecan deposition was attenuated by addition of the NF-κB inhibitor, BMS-345541, and the signal transduction and activator of transcription-1/3 inhibitor, pyridone 6, respectively. CSE (5%) increased IL-8 release from COPD fibroblasts more than non-COPD fibroblasts. This increase was attenuated by BMS-345541. Matrix deposited after 5% CSE stimulation increased proliferation of fibroblasts, but did not alter cytokine release. ECM produced from COPD fibroblasts after CSE exposure has proproliferative effects. Thus, the ECM in patients with COPD may create an environment that promotes airway remodeling.