Primary rat alveolar epithelial cells for use in biotransformation and toxicity studies - Surfactants

Primary rat alveolar epithelial cells for use in biotransformation and toxicity studies
Received 17 May 2005; accepted 17 October 2005. Available online 2 December 2005.
Tanja Hansena, Maren Blickwedea and J?rgen Borlak, a,
Toxicology in Vitro
Volume 20, Issue 5 , August 2006
ScienceDirect
aFraunhofer Institute of Toxicology and Experimental Medicine, Drug Research and Medical Biotechnology, Nikolai-Fuchs-Str. 1, 30625 Hannover, Germany
Abstract
The alveolar epithelium may function as a barrier for airborne xenobiotics, and in vitro models mimicking this barrier are useful for metabolism and toxicity studies. To gain insight into the metabolic competence of alveolar epithelial cells (AECs), we investigated transcript expression of 10 different cytochrome P450 monooxygenases as well as expression of surfactant proteins A to D. We also investigated gene expression of the transcription factors PCNA, TTF-1, HNF3? , GATA-6, C/EBPa and C/EBPd which drive, at least in part, development and differentiation of alveolar epithelium. We further studied the metabolism of testosterone, a substrate for cytochrome P450 (CYP) monooxygenases, in cultures of AECs. Essentially, medium supplementation with 5% rat serum, as opposed to 10% FCS, promoted a high level of differentiation, as judged by the mRNA expression of CYP monooxygenases, e.g. 1A1, 1A2, 2B1 and 2J3, the expression of the surfactant proteins A, B, and C, the immunohistochemical staining for surfactant protein C, and staining for alkaline phosphatase activity. Further, AECs, when cultured in the presence of 5% rat serum, promoted metabolic competence, as evidenced by the fingerprinting of individual testosterone metabolites. We thus characterized AECs in culture and found these respiratory epithelial cells to express an array of differentiation markers and showed these cultures to be metabolically competent under optimized culture conditions.
Keywords: Alveolar epithelial cells; Differentiation markers; Cytochrome P450 monooxygenases; Testosterone metabolism
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