A polarized salivary cell monolayer useful for studying transepithelial fluid movement in vitro

Abstract

There are no reported, convenient in vitro models for studying polarized functions in salivary epithelial cells. Accordingly, we examined three often-used salivary cell lines for their ability to form a polarized monolayer on permeable, collagen-coated polycarbonate filters. Only the SMIE line, derived from rat submandibular gland, had this ability. The SMIE cell monolayer exhibited junctional complexes, with a tight-junction-associated protein, ZO-1, localized to cell-cell contact areas. The Na+/K+-ATPase alpha1-subunit was detected predominantly in the basolateral membranes, while the Na+/H+ exchanger isoform 2 appeared primarily in the apical membranes. Using adenovirus-mediated cDNA transfer, SMIE cells were shown to be capable of routing marker proteins (beta-galactosidase +/- a nuclear targeting signal, alpha1-antitrypsin, aquaporin-1) to appropriate locations. Furthermore, this salivary cell monolayer provided a convenient tool for studying aquaporin-1-mediated, osmotically directed, transepithelial fluid movement in vitro. Thus, SMIE cells appear to be a useful experimental model with which to study some polarized functions in a salivary epithelial cell line.

Systemic action of human growth hormone following adenovirus-mediated gene transfer to rat submandibular glands

“…Initially, to determine if AdCMVhGH could direct the expression of hGH in vitro, we infected SMIE cells, an epithelial cell line derived from the rat submandibular gland. 15 On Northern blot analysis infected SMIE cells transcribed an approximately 900 nt mRNA which hybridized with an hGH probe (not shown). This sized transcript is expected for the mature hGH, including the polyadenylation sequence.…”

“…In general, hGH levels decreased approximately 50% between 48 and 72 h. In some experiments, we also examined the polarity of hGH secretion by culturing SMIE cells on collagen-coated polycarbonate filters, a condition in which the cells are able to form a polarized monolayer. 15 The hGH secreted by the SMIE cells is primarily found in the basal side media. The cells were infected with AdCMVhGH at a MOI of 10 and produced approximately 270 ng hGH/3 × 10 6 cells in 24 h. Of this total hGH, 91.5% was detected in the culture medium and approximately 80% of that was found in basal side media (193 versus 54 ng found in the apical media).…”

Apical Localization of a Functional TRPC3/TRPC6-Ca2+-Signaling Complex in Polarized Epithelial Cells

“…Measurement of Transepithelial Electrical Resistance (TER)-TER across cell monolayers was measured as described previously (24). Briefly, cells were seeded at a density of 1 ϫ 10 6 per well and grown to confluence in 24-mm Transwell culture chambers (Corning Costar).…”

“…TRPC3 did not show polarized localization when grown on plastic (data not shown). We further examined localization of TRPC3 in a salivary gland epithelial cell line (SMIE) (24), which also forms polarized, high resistance monolayers on Transwell filters (TER measurements are not shown). As in MDCK cells, TRPC3-FLAG was seen in the apical membrane of polarized SMIE cells (SMIE, Fig.…”

Differential Sorting of Human Parathyroid Hormone After Transduction of Mouse and Rat Salivary Glands

“…In vitro studies were done with the SMIE cell line (He et al, 1998b) and the A5 cell line (Brown et al, 1989); both are rat submandibular cell lines. Cells were seeded at 80% confluence in 12-well plates in Dulbecco's modified Eagle's medium (DMEM)-10% fetal calf serum (FCS) and transduced with Ad.hPTH at multiplicities of infection (MOIs) ranging from 10 2 to 2 ϫ 10 4 .…”