Polarized secretion of fibrinogen by lung epithelial cells.
نویسندگان
چکیده
The lung epithelium has recently been identified as a novel site of fibrinogen (FBG) biosynthesis. A coordinated upregulation of A alpha, B beta, and gamma chain FBG gene transcription occurs upon stimulation of A549 lung epithelial cells with dexamethasone (DEX) and the proinflammatory mediator interleukin-6 (IL-6). Subsequently, the cells synthesize and secrete fully assembled FBG. This study addresses the polarity of such FBG secretion by A549 cells cultured on polycarbonate membrane filters. After induction with IL-6 and DEX, cells were metabolically labeled, and FBG was immunopurified from the apical and basolateral chambers. Analysis by gel electrophoresis revealed that A549 cells secreted newly synthesized FBG in a polarized manner, with the majority (80%) of FBG secreted basolaterally. Consistent with this observation, immunoelectron microscopy using Protein A-gold labeling showed FBG within secretory vesicles in close proximity to the basolateral aspect of the A549 cell membrane. Polarized secretion was microtubule-dependent since depolymerization using colchicine significantly reduced the basolateral component of secretion, causing intracellular retention of FBG. These data provide evidence that FBG is secreted by lung alveolar epithelial cells vectorially toward the basement membrane, which may reflect in vivo processes associated with local injury, inflammation, and repair mechanisms.
منابع مشابه
Polarized and Non-Poarized Human Oviduct Epithelial Cell Ultrastructure in Vitro
Purpose: This study designed to examine polarized culture of epithelial cells from human ovidutc and their ultrastracture under polarizing condition. Materials and Methods: The human oviduct was obtained from patients having undergone total hysterectomy and epithelial cells were isolated using collagenase type I. The epithelial cells were either cultured on ECM (Extracellular matrix) Gel coate...
متن کاملتاثیر تک لایه های قطبی و غیر قطبی سلول های پوششی لوله رحم انسان بر تکوین جنین های دو سلولی موش
Background and purpose: Ëmbryo co-culture systems with somatic cells have been a subject of extensive study as valuable tools to promote embryo in vitro development. The aim of this study was to evaluate, the Ëffects of a special kind of co-culture system in which somatic cells were cultured as polarized monolayer on mouse embryo development. Materials and methods : Human oviduct was obtai...
متن کاملEffect of Two Polarized Culture System Prepared From Human Female Genital Tract on Mouse Embryo Development
Purpose: To compare effects of polarized epithelial monolayer prepared from human oviduct and uterus on mouse one and two-cell embryo development. Materials and Methods: Human oviduct and endometrial tissue was obtained from patients who had undergone total hysterectomy. The epithelial cells were isolated from tissue and cultured on extracellular matrix (ECM) Gel coated Millipore filter insert...
متن کاملEffect of Matrigel on Function and Morphology of Human Endometrial Epithelial Cell in vitro
The importance of extra cellular matrix (ECM) in development and function of different cells has been reported but little is known about its role in human endometrial epithelial cells. The aim of the present study was to examine effects of artificial ECM (Matrigel) and progesterone on the function and morphology of human endometrial epithelial cells in vitro. Methods: Endometrial samples were ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- American journal of respiratory cell and molecular biology
دوره 17 1 شماره
صفحات -
تاریخ انتشار 1997