Rabbit Anti-Human BLM Polyclonal Antibody

Background Idiopathic pulmonary fibrosis (IPF) is a devastating disease with a median survival of only three to 5 years. Fibroblast proliferation is a hallmark of IPF as is secretion of extracellular matrix proteins from fibroblasts. However, it is still uncertain how IPF fibroblasts acquire the ability to progressively proliferate. Periostin is a matricellular protein highly expressed in the lung tissues of IPF patients, playing a critical role in the pathogenesis of pulmonary fibrosis. However, it remains undetermined whether periostin affects lung fibroblast proliferation. Methods In this study, we first aimed at identifying periostin-dependently expressed genes in lung fibroblasts using DNA microarrays. We then examined whether expression of cyclins and CDKs controlling cell cycle progression occur in a periostin-dependent manner. We next examined whether downregulation of cell proliferation-promoting genes by knockdown of periostin or integrin, a periostin receptor, using siRNA, is reflected in the cell proliferation of lung fibroblasts. We then looked at whether lung fibroblasts derived from IPF patients also require periostin for maximum proliferation. We finally investigated whether CP4715, a potent inhibitor against integrin alpha(V)beta(3) (a periostin receptor), which we have recently found blocks TGF-beta signaling, followed by reduced BLM-induced pulmonary fibrosis in mice, can block proliferation of lung fibroblasts derived from IPF patients. Results Many cell-cycle-related genes are involved in the upregulated or downregulated genes by periostin knockdown. We confirmed that in lung fibroblasts, periostin silencing downregulates expression of several cell-cycle-related molecules, including the cyclin, CDK, and, E2F families, as well as transcription factors such as B-MYB and FOXM1. Periostin or integrin silencing slowed proliferation of lung fibroblasts and periostin silencing increased the distribution of the G0/G1 phase, whereas the distribution of the G2/M phase was decreased. Lung fibroblasts derived from IPF patients also required periostin for maximum proliferation. Moreover, CP4715 downregulated proliferation along with expression of cell-cycle-related genes in IPF lung fibroblasts as well as in normal lung fibroblasts. Conclusions Periostin plays a critical role in the proliferation of lung fibroblasts and the present results provide us a solid basis for considering inhibitors of the periostin/integrin alpha(V)beta(3) interaction for the treatment of IPF patients.

This study was designed to investigate the effect of particulate matter with a diameter of <= 2.5 mu m(PM2.5) on bleomycin (BLM) induced pulmonary fibrosis. Thirty-two Sprague Dawley rats were assigned into four groups (intratracheal instillation of 500 mu L of PBS (control), 2 mg/kg PM2.5, 3.5 mg/kg BLM A5, and BLM plus 2.0 mg/kg PM2.5) and were fed for 14 days. All rats were sacrificed after the study. Lung tissues and bronchoalveolar lavage fluid were prepared for histological and biological analysis. We found that PM2.5 caused dose-trend pulmonary alveolitis and fibrosis. Histological scores, expression of alpha-SMA and Collagen I as well as contents of TNF-alpha and IL-6 in lung tissues were upregulated by treatment of PM2.5. PM2.5 did not change the percentage of neutrophils and macrophages. The expression of endoplasmic reticulum (ER) stress markers Chop and GRP78 was upregulated by treatment of PM2.5. In comparison with either PM2.5 or BLM treatment, BLM plus PM2.5 treatment induced higher histological scores, higher expression of alpha-SMA, collagen I, TNF-alpha, IL-6, Chop, and GRP78, with increased neutrophil counts and decreased macrophage counts. We concluded that PM2.5 instillation caused pulmonary alveolitis and fibrosis by stimulating ER stress responses in rat. PM2.5 also showed a synergistic effect on BLM-induced pulmonary fibrosis.