title: LGL1 modulates proliferation, apoptosis, and migration of human fetal lung fibroblasts.
abstract: Rapid growth and formation of new gas exchange units (alveogenesis) are hallmarks of the perinatal lung. Bronchopulmonary dysplasia (BPD), common in very premature infants, is characterized by premature arrest of alveogenesis. Mesenchymal cells (fibroblasts) regulate both lung branching and alveogenesis through mesenchymal-epithelial interactions. Temporal or spatial deficiency of late-gestation lung 1/cysteine-rich secretory protein LD2 (LGL1/CRISPLD2), expressed in and secreted by lung fibroblasts, can impair both lung branching and alveogenesis (LGL1 denotes late gestation lung 1 protein; LGL1 denotes the human gene; Lgl1 denotes the mouse/rat gene). Absence of Lgl1 is embryonic lethal. Lgl1 levels are dramatically reduced in oxygen toxicity rat models of BPD, and heterozygous Lgl1(+/-) mice exhibit features resembling human BPD. To explore the role of LGL1 in mesenchymal-epithelial interactions in developing lung, we developed a doxycycline (DOX)-inducible RNA-mediated LGL1 knockdown cellular model in human fetal lung fibroblasts (MRC5(LGL1KD)). We assessed the impact of LGL1 on cell proliferation, cell migration, apoptosis, and wound healing. DOX-induced MRC5(LGL1KD) suppressed cell growth and increased apoptosis of annexin V(+) staining cells and caspase 3/7 activity. LGL1-conditioned medium increased migration of fetal rat primary lung epithelial cells and human airway epithelial cells. Impaired healing by MRC5(LGL1KD) cells of a wound model was attenuated by addition of LGL1-conditioned medium. Suppression of LGL1 was associated with dysregulation of extracellular matrix genes (downregulated MMP1, ColXVα1, and ELASTIN) and proapoptosis genes (upregulated BAD, BAK, CASP2, and TNFRSF1B) and inhibition of 44/42MAPK phosphorylation. Our findings define a role for LGL1 in fibroblast expansion and migration, epithelial cell migration, and mesenchymal-epithelial signaling, key processes in fetal lung development.
authors.affiliation: Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada;
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Hospital for Sick Children Research Institute, Toronto, Ontario, Canada; Departments of Pediatrics and Physiology, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Neil B
authors.initials: NB
authors.lastname: Sweezey
authors.affiliation: Departments of Human Genetics and Pediatrics, McGill University, Montreal, Quebec, Canada; Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada; feige.kaplan@mcgill.ca.
authors.forename: Feige
authors.initials: F
authors.lastname: Kaplan
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism; D001997:Bronchopulmonary Dysplasia / Q000196:embryology / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism*; D002465:Cell Movement / Q000502:physiology*; D049109:Cell Proliferation / Q000502:physiology*; D016326:Extracellular Matrix Proteins / Q000096:biosynthesis / Q000235:genetics; D005333:Fetus / Q000166:cytology / Q000196:embryology*; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D050835:Interferon Regulatory Factors / Q000235:genetics / Q000378:metabolism*; D008168:Lung / Q000166:cytology / Q000196:embryology*; D051379:Mice; D018345:Mice, Knockout; D048052:Mitogen-Activated Protein Kinase 3 / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D020545:Respiratory Mucosa / Q000166:cytology / Q000196:embryology; D015398:Signal Transduction / Q000502:physiology
chemical_list: D051017:Apoptosis Regulatory Proteins; C525599:CRISPLD2 protein, human; D015815:Cell Adhesion Molecules; D016326:Extracellular Matrix Proteins; D050835:Interferon Regulatory Factors; D048052:Mitogen-Activated Protein Kinase 3
keywords: Lgl1(Crispld2); bronchopulmonary dysplasia; human fetal lung fibroblast; mesenchymal-epithelial interaction; proliferation/migration/apoptosis