Alveolar cell monolayers

Dodoo AN, Bansal SS, Barlow DJ, Bennet F, Hider RC, Lansley AB, Lawrence MJ, Marriott C (2000) Use of alveolar cell monolayers of varying electrical resistance to measure pulmonary peptide transport. J Pharm Sci 89(2) 223-231... 

As a nonspecific fluid-phase endocytosis marker, HRP was used to evaluate the transport characteristics across rat alveolar epithelia cell monolayers. HRP was transported relatively intact (about 50%) across the alveolar barrier via nonspecific fluid-phase endocytosis. The permeability coefficient of HRP was decreased upon lowering the temperature [51], but after conjugation with transferrin via a disulfide linkage, HRP uptake by alveolar cell monolayers was significantly increased. Receptor-mediated internalization of the conjugated HRP was verified by competition for the transferrin receptor [52]. 

Figure 16 Correlation of effective pore radius of the paracellular route of rat alveolar epithelial cell monolayers with transepithelial electrical resistance and time in culture. Pore radii were calculated from the data shown in Figure 14.

Matsukawa Y, Lee VHL, Crandall ED, Kim K-J (1997) Size-dependent dextran transport across rat alveolar epithelial cell monolayers. J Pharm Sci 86 305-309. 

Kobayashi S, Kondo S, Juni K (1995) Permeability of peptides and proteins in human cultured alveolar A549 cell monolayer. Pharm Res 12(8) 1115-1119... 

Wang Z, Zhang Q (2004) Transport of proteins and peptides across human cultured alveolar A549 cell monolayer. Int J Pharm 269(2) 451—456... 

Shen J, Elbert KJ, Yamashita F, Lehr CM, Kim KJ, Lee VH (1999) Organic cation transport in rabbit alveolar epithelial cell monolayers. Pharm Res 16(8) 1280-1287... 

Morimoto K, Yamahara H, Lee VH, Kim KJ (1993) Dipeptide transport across rat alveolar epithehal cell monolayers. Pharm Res 10(11) 1668—1674... 

Widera A, Kim KJ, Crandall ED, Shen WC (2003) Transcytosis of GCSF-transferrin across rat alveolar epithelial cell monolayers. Pharm Res 20(8) 1231— 1238... 

Bur M, Huwer H, Lehr CM, Hagen N, Guldbrandt M, Kim KJ, Ehrhardt C (2006) Assessment of transport rates of proteins and peptides across primary human alveolar epithelial cell monolayers. Eur J Pharm Sci 28(3) 196-203... 

Endter S, Becker U, Damn N, Huwer H, Lehr CM, Gumbleton M, Ehrhardt C (2007) P-glycoprotein (MDR1) functional activity in human alveolar epithelial cell monolayers. Cell Tissue Res [Epub ahead of print] doi 10.1007/s00441-006-... 

Ehrhardt C, Kneuer C, Baldes C, Kim KJ, Lehr CM (2006) Albuterol is net absorbed across human alveolar epithelial cell monolayers. Proc Am Thor Soc 3A761... 

Kim KJ, Matsukawa Y, Yamahara H, Kalra VK, Lee VH, Crandall ED (2003) Absorption of intact albumin across rat alveolar epithelial cell monolayers. Am J Physiol 284(3) L458-L465... 

Matsukawa,Y., H. Yamahara,V.H. Lee, E.D. Crandall, and K.J. Kim. 1996. Horseradish peroxidase transport across rat alveolar epithelial cell monolayers. Pharm. Res. 13 1331-1335. 

The rate of protein clearance has been estimated as 10% of the rate of fluid clearance from alveoli [173]. IgG clearance is probably mediated by FcRn transcytosis in distal type I alveolar epithelium and more proximal bronchial epithelium. Type I alveolar epithelium and bronchial epithelium contain the necessary subcellular structures for FcRn-mediated transcytosis vesicles, membrane invaginations, caveolae, and clathrin-coated pits [173,174], FcRn mRNA is expressed in lung although the cell types and locations have not yet been determined [112], Moreover, primary alveolar epithelial monolayer cell cultures express functional FcRn [173], plgA-R/SC transcytosis is thought to contribute little to distal (alveolar) airway IgG transport but might mediate more proximal (bronchial or bronchiolar) IgA transport [173], Uptake of an aerosolized IgG Fc-erythropoietin fusion molecule and subsequent erythropoietin-induced reticulocytosis has been demonstrated in human and nonhuman primates [175],... 

Exposure of rat alveolar type II cells plated on polycarbonate filters in serum-free medium to 10 ng keratinocyte growth factor/ml on day 4 resulted in dose-dependent increases in short-circuit current (7sc) across alveolar epithelial cell monolayers compared with controls by day 5, with further increase occurring through day 8 (Borok et al. 1998). Relative Na -K -ATPase Qi-subunit mRNA abundance was increased by 41 % on day 6 and 8 after exposure to keratinocyte growth factor, whereas a2-subunit mRNA remained only marginally detectable in both the absence and presence of keratinocyte growth factor. Levels of mRNA for the Pi-subunit of Na" -K -ATPase did not increase, whereas cellular Oi-and Pi-subunit protein increased 70 and 31 %, respectively, on day 6. mRNA for a-, P-, and y-rat epithelial Na channel all decreased in abundance after treatment with keratinocyte growth factor. 

Adenosine triphosphatase (ATPase) was localised in the plasmalemma of guinea pig peritoneal macrophages (North 1966). Enzymatic activity could be removed from the cells by trypsin. While scanning electron microscopy of endothelial cells monolayers harvested using 0.25% trypsin or 0.125 % trypsin + 0.01 % EDTA failed to reveal any distinctive differences in their surface morphology (Kirkpatrick et al. 1986), bovine alveolar macrophages showed blebbing (Brehm 1996). 

Goodman, B., Brown, S. E. S., and Crandall, E. D., 1984, Regulation of transport across pulmonary alveolar epithelial cell monolayer, J. Appl. Physiol. 57 703-710. 

Transwell experiments were also performed to investigate BoNT / A transcytosis across a human pulmonary adenocarcinoma cell line (Calu-3), the MDCK cell line, and a primary rat alveolar epithelial cell line (Park and Simpson, 2003). Efficient BoNT/A transcytosis in both directions across polarized Calu-3 monolayers was observed, while toxin transcytosis occurred at a much lower rate across MDCK cells. These findings were in agreement with previous work demonstrating that the efficiency of BoNT/A transcytosis across MEXZK mono-layers was much lower than that observed across gut epithelial cells (Maksymowych and Simpson, 1998). BoNT/ A transcytosis was also observed across primary rat alveolar cells, although at a slightly slower rate than that seen for the human adenocarcinoma cells (Park... 

We used in vitro models of lung epithelial cell lines or primary cells to determine E25 permeability. Two different cell types were used to mimic the airway and alveolar epithelium of the lung to study transport. Calu-3, a human cell line derived from an airway carcinoma, when grown at an air/liquid interface, differentiate to form a secretory airway epithelium (17). Rat primary epithelial cells isolated as described by Cheek et al. (18) form a tight barrier similar in structure and function to the alveolar surface. Both cell types when grown to confluence form tight junctions and differentiate and polarize so that the apical or air surface has different characteristics than the basolateral or blood side. The typical transepithelial resistance observed was 350 or >1000 ohms-cm for Calu-3 cells or primary rat alveolar cells, respectively. Once an acceptable resistance was achieved, E25 (2 mg/mL) was placed in either the apical or the basolateral chamber. Cell monolayers were incubated at 37°C for up to 3 hours and ELISA measured the amount of E25 that translocated the epithelial layer and appeared in the receiver well. The apparent permeability (Papp) of the epithelium for E25 was calculated as ... 

Cheek JM, Evans MJ, Crandall ED. Type I ceU-Uke morphology in tight alveolar epithelial monolayers. Exp Cell Res 1989 184 375-387. 

Figure 14 Observed permeability coefficients of urea and mannitol across monolayers of rat alveolar epithelial cells in primary culture in the Transwell system are correlated with transepithelial electrical resistance and days in culture.

Steimer A, Franke H, Haltner-Ukomado E, Laue M, Ehrhardt C, Lehr CM (2007) Monolayers of porcine alveolar epithelial cells in primary culture as an in vitro model for drug absorption studies. Eur J Pharm Biopharm [Epub ahead of print] doi 10.1016/j.ejpb.2006.11.006... 

Cheek JM, Kim KJ, Crandall ED (1989) Tight monolayers of rat alveolar epithelial cells bioelectric properties and active sodium transport. Am J Physiol 256 (3 Pt 1 ) C688-C693... 

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