Exuberant fibroblast activity compromises lung function via ADAMTS4.
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ABSTRACT:
SUBMITTER: Boyd DF
PROVIDER: S-EPMC7883627 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundMyofibroblasts are the critical effector cells in the pathogenesis of pulmonary fibrosis which carries a high degree of morbidity and mortality. We have previously identified Type II TGF? receptor interacting protein 1 (TRIP-1), through proteomic analysis, as a key regulator of collagen contraction in primary human lung fibroblasts--a functional characteristic of myofibroblasts, and the last, but critical step in the process of fibrosis. However, whether or not TRIP-1 modulates fibroblast trans-differentiation to myofibroblasts is not known.MethodsTRIP-1 expression was altered in primary human lung fibroblasts by siRNA and plasmid transfection. Transfected fibroblasts were then analyzed for myofibroblast features and function such as ?-SMA expression, collagen contraction ability, and resistance to apoptosis.ResultsThe down-regulation of TRIP-1 expression in primary human lung fibroblasts induces ?-SMA expression and enhances resistance to apoptosis and collagen contraction ability. In contrast, TRIP-1 over-expression inhibits ?-SMA expression. Remarkably, the effects of the loss of TRIP-1 are not abrogated by blockage of TGF? ligand activation of the Smad3 pathway or by Smad3 knockdown. Rather, a TRIP-1 mediated enhancement of AKT phosphorylation is the implicated pathway. In TRIP-1 knockdown fibroblasts, AKT inhibition prevents ?-SMA induction, and transfection with a constitutively active AKT construct drives collagen contraction and decreases apoptosis.ConclusionsTRIP-1 regulates fibroblast acquisition of phenotype and function associated with myofibroblasts. The importance of this finding is it suggests TRIP-1 expression could be a potential target in therapeutic strategy aimed against pathological fibrosis.
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Project description:PurposeFibrosis in peripheral airways is responsible for airflow limitation in chronic obstructive pulmonary disease (COPD). Annexin A1 modulates several key biological events during inflammation. However, little is known about its role in airway fibrosis in COPD. We investigated whether levels of Annexin A1 were upregulated in patients with COPD, and whether it promoted airway fibrosis.MethodsWe quantified serum Annexin A1 levels in never-smokers (n=12), smokers without COPD (n=11), and smokers with COPD (n=22). Correlations between Annexin A1 expression and clinical indicators (eg, lung function) were assessed. In vitro, human bronchial epithelial (HBE) cells were exposed to cigarette smoke extract (CSE) and Annexin A1 expression was assessed. Primary human lung fibroblasts were isolated from patients with COPD and effects of Annexin A1 on fibrotic deposition of lung fibroblasts were evaluated.ResultsSerum Annexin A1 was significantly higher in patients with Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines stage III or IV than in those with GOLD stages I or II (12.8±0.8 ng/mL versus 9.8±0.7 ng/mL; p=0.016). Annexin A1 expression was negatively associated with airflow obstruction (forced expiratory volume in one second % predicted; r=-0.72, p<0.001). In vitro, Annexin A1 was significantly increased in CSE-exposed HBE cells in a time- and concentration-dependent manner. Annexin A1 promoted lung fibroblasts proliferation, migration, differentiation, and collagen deposition via the ERK1/2 and p38 mitogen-activated protein kinase pathways.ConclusionAnnexin A1 expression is upregulated in patients with COPD and affects lung fibroblast function. However, more studies are needed to clarify the role of Annexin A1 in airway fibrosis of COPD.
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