Ruoqi Peng

Bleomycin induces molecular changes directly relevant to idiopathic pulmonary fibrosis: a model for "active" disease.

The preclinical model of bleomycin-induced lung fibrosis, used to investigate mechanisms related to idiopathic pulmonary fibrosis (IPF), has incorrectly predicted efficacy for several candidate compounds suggesting that it may be of limited value. As an attempt to improve the predictive nature of this model, integrative bioinformatic approaches were used to compare molecular alterations in the lungs of bleomycin-treated mice and patients with IPF. Using gene set enrichment analysis we show for the first time that genes differentially expressed during the fibrotic phase of the single challenge bleomycin model were significantly enriched in the expression profiles of IPF patients. The genes that contributed most to the enrichment were largely involved in mitosis, growth factor, and matrix signaling. Interestingly, these same mitotic processes were increased in the expression profiles of fibroblasts isolated from rapidly progressing, but not slowly progressing, IPF patients relative to control subjects. The data also indicated that TGFβ was not the sole mediator responsible for the changes observed in this model since the ALK-5 inhibitor SB525334 effectively attenuated some but not all of the fibrosis associated with this model. Although some would suggest that repetitive bleomycin injuries may more effectively model IPF-like changes, our data do not support this conclusion. Together, these data highlight that a single bleomycin instillation effectively replicates several of the specific pathogenic molecular changes associated with IPF, and may be best used as a model for patients with active disease.

BET Bromodomain Proteins Mediate Downstream Signaling Events following Growth Factor Stimulation in Human Lung Fibroblasts and Are Involved in Bleomycin-Induced Pulmonary Fibrosis

Epigenetic alterations, such as histone acetylation, regulate the signaling outcomes and phenotypic responses of fibroblasts after growth factor stimulation. The bromodomain and extra-terminal domain–containing proteins (Brd) bind to acetylated histone residues, resulting in recruitment of components of the transcriptional machinery and subsequent gene transcription. Given the central importance of fibroblasts in tissue fibrosis, this study sought to determine the role of Brd proteins in human lung fibroblasts (LFs) after growth factor stimulation and in the murine bleomycin model of lung fibrosis. Using small interfering RNA against human Brd2 and Brd4 and pharmacologic Brd inhibitors, this study found that Brd2 and Brd4 are essential in mediating the phenotypic responses of LFs downstream of multiple growth factor pathways. Growth factor stimulation of LFs causes increased histone acetylation, association of Brd4 with growth factor–responsive genes, and enhanced transcription of these genes that could be attenuated with pharmacologic Brd inhibitors. Of note, lung fibrosis induced after intratracheal bleomycin challenge in mice could be prevented by pretreatment of animals with pharmacologic inhibitors of Brd proteins. This study is the first demonstration of a role for Brd2 and Brd4 proteins in mediating the responses of LFs after growth factor stimulation and in driving the induction of lung fibrosis in mice in response to bleomycin challenge.

Discovery of Highly Selective and Orally Active Lysophosphatidic Acid Receptor-1 Antagonists with Potent Activity on Human Lung Fibroblasts

Lysophosphatidic acid is a class of bioactive phospholipid that mediates most of its biological effects through LPA receptors, of which six isoforms have been identified. The recent results from LPA1 knockout mice suggested that blocking LPA1 signaling could provide a potential novel approach for the treatment of idiopathic pulmonary fibrosis. Here, we report the design and synthesis of pyrazole- and triazole-derived carbamates as LPA1-selective and LPA1/3 dual antagonists. In particular, compound 2, the most selective LPA1 antagonist reported, inhibited proliferation and contraction of normal human lung fibroblasts (NHLF) following LPA stimulation. Oral dosing of compound 2 to mice resulted in a dose-dependent reduction of plasma histamine levels in a murine LPA challenge model. Furthermore, we applied our novel antagonists as chemistry probes and investigated the contribution of LPA1/2/3 in mediating the pro-fibrotic responses. Our results suggest LPA1 as the major receptor subtype mediating LPA-induced proliferation and contraction of NHLF.

House dust mite models: Will they translate clinically as a superior model of asthma?

Canada; Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec, Canada; the Department of Oncology and the Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Quebec, Canada; the Division of Dermatology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada; the Division of Allergy and Clinical Immunology, Department of Pediatrics, McGill University, Montreal, Quebec, Canada; the University of Dundee, Dundee, United Kingdom; Laval University, Quebec City, Quebec, Canada; the Departments of Human Genetics and Medicine, McGill University, Montreal, Quebec, Canada; Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada; Trinity College Dublin, Dublin, Ireland; and the Division of Allergy/Clinical Immunology, Department of Medicine, McGill University, Montreal, Quebec, Canada. E-mail: yuka.asai@mail.mcgill.ca. Y.A. is supported by a Canadian Institutes for Health Research Fellowship, the Allergy, Genes and Environment Network of Centres of Excellence (AllerGen NCE), and the Canadian Dermatology Foundation (CDF). C.G. is supported by the Weekend to End Cancer at the Jewish General Hospital. P.R.H. is supported by the CDF and the University of Saskatchewan’s Department of Medicine Research Fund. M.B.-S. is an Emerging Clinician-Scientist of the AllerGen NCE. S.J.B. is supported by a Wellcome Trust Intermediate Clinical Fellowship (ref 086398/Z/08/Z). A.D.I. is supported by the National Children’s Research Centre, Dublin, and the Wellcome Trust. Research in the lab of W.H.I.M. is supported by grants from the British Skin Foundation, National Eczema Society, Medical Research Council (G0700314), the Wellcome Trust (090066/B/09/Z and 092530/Z/10/Z), and donations from anonymous families affected by eczema in the Tayside Region of Scotland. TheMcGill peanut allergy case group is supported by the Foundation of the Montreal Children’s Hospital and by grants from the Canadian Allergy, Asthma, and Immunology Foundation and the AllerGen NCE. Disclosure of potential conflict of interest: Y. Asai has received research support from the Foundation of the Montreal Children’s Hospital, AllerGen NCE, Canadian Allergy, Asthma, and Immunology Foundation, and the CIHR and has received travel support from the Canadian Dermatology Foundation. S. J. Brown has received research support from the Wellcome Trust and has received travel support for the 2012 AAAAI Meeting and BSACI Meeting. J. Bussi eres and F. Rousseau have received research support from AllerGen NCE. W. H. I. McLean has received research support from the Wellcome Trust. The rest of the authors declare that they have no relevant conflicts of interest. Parts of this work have been previously presented at the Dermatogenetics Conference (Nature Genetics and Journal of Investigative Dermatology joint meeting, Miami, Florida, February 9-12, 2012) and the AllerGen NCE 2012 Annual Conference (Innovation from cell to society; Toronto, Ontario, Canada, February 5-7, 2012).