Prevention of Bleomycin-Induced Pulmonary Fibrosis by a Novel Antifibrotic Peptide with Relaxin-Like Activity

Abstract

Pulmonary fibrosis is a progressive and lethal lung disease characterized by accumulation of extracellular matrix and loss of pulmonary function. No cure exists for this pathologic condition, and current treatments often fail to slow its progression or relieve its symptoms. Relaxin was previously shown to induce a matrix-degrading phenotype in human lung fibroblasts in vitro and to inhibit pulmonary fibrosis in vivo. A novel peptide that targets the relaxin RXFP1/LGR7 receptor was recently identified using our computational platform designed to predict novel G protein-coupled receptor peptide agonists. In this study, we examined the antifibrotic properties of this novel peptide, designated CGEN25009, in human cell-based assays and in a murine model of bleomycin-induced pulmonary fibrosis. Similar to relaxin, CGEN25009 was found to have an inhibitory effect on transforming growth factor-␤1-induced collagen deposition in human dermal fibroblasts and to enhance MMP-2 expression. The peptide's biological activity was also similar to relaxin in generating cellular stimulation of cAMP, cGMP, and NO in the THP-1 human cell line. In vivo, 2-week administration of CGEN25009 in a preventive or therapeutic mode (i.e., concurrently with or 7 days after bleomycin treatment, respectively) caused a significant reduction in lung inflammation and injury and ameliorated adverse airway remodeling and peribronchial fibrosis. The results of this study indicate that CGEN25009 displays antifibrotic and anti-inflammatory properties and may offer a new therapeutic option for the treatment of pulmonary fibrosis.

International Union of Basic and Clinical Pharmacology. XCV. Recent Advances in the Understanding of the Pharmacology and Biological Roles of Relaxin Family Peptide Receptors 1–4, the Receptors for Relaxin Family Peptides

“…Short linear peptides derived from a naturally occurring protein containing a collagen-like repeat have been reported to act at RXFP1 (Shemesh et al, 2009). Although the effects produced by the peptides CGEN-25009 and CGEN-25010 in several systems were extremely variable and the effects of human relaxin in these systems unusual (Shemesh et al, 2008(Shemesh et al, , 2009, there is some evidence to suggest relaxin-like activity of these peptides in THP-1 cells and in a fibrosis model (Pini et al, 2010). In the latter study, CGEN-25009 and human relaxin increased cAMP, cGMP, and nitrite and decreased collagen deposition and increased matrix metalloproteinase-2 (MMP-2) activity in human dermal fibroblasts (Pini et al, 2010).…”

Role of histamine H 4 receptor ligands in bleomycin-induced pulmonary fibrosis

“…At day 21 after surgery, the mice were subjected to measurement of airway resistance to inflation, a functional parameter related to fibrosis-induced lung stiffness, by using a constant volume mechanical ventilation method [27,28]. In brief, upon anaesthesia, the mice were operated on to insert a 22-gauge cannula (Venflon 2; Viggo Spectramed, Windlesham, UK, 0.8 mm diameter) into the trachea and then ventilated with a small-animal respirator (Ugo Basile, Comerio, Italy), adjusted to deliver a tidal volume of 0.8 ml at a rate of 20 strokes/min.…”

Expression of RXFP1 Is Decreased in Idiopathic Pulmonary Fibrosis. Implications for Relaxin-based Therapies

“…Enthusiasm for this strategy ebbed following the failure of a clinical trial of relaxin therapy for systemic sclerosis (SSc) (8,9). The recent success of relaxin in clinical trials for acute heart failure (10), however, has renewed interest in studying relaxin-based therapies in fibrotic diseases, including IPF (11,12).…”

“…To investigate the potential application of relaxin-based therapies in IPF, we queried the LTRC gene expression dataset to determine expression of RXFP1 in IPF. We employed a relaxin-like peptide, CGEN25009 (12), as a model of a relaxinbased therapy to test in bleomycin injury and in ex vivo human lung fibroblasts.…”