Carmel Z, Amsallem H, Métioui M, Dehaye J P, Moran A
Department of Physiology, Faculty of Health Science, Ben-Gurion University, Beer-Sheva, Israel.
Arch Oral Biol. 1999 May;44 Suppl 1:S63-6. doi: 10.1016/s0003-9969(99)90024-9.
A major obstacle in studying the physiological and biochemical processes of salivary secretion is the lack of a good ductal cell line model. HSY, an immortalised cell line originating from human parotid gland intercalated ducts, provides a possible model for purinergic mechanisms in ductal cells. Unlike the biphasic dose response to ATP of isolated submandibular ductal cells, the rise in [Ca2+]i in HSY cells shows single Michaelis-Menten kinetics with an apparent Ka of 0.8 microM. Pre-incubation with thapsigargin inhibited the ATP induced [Ca2+]i rise. Both ATP (10 microM) and carbachol (100 microM) increased IP3 production. Intercalated duct cells may differentiate into acinar or ductal cells in response to appropriate stimuli from extracellular matrix We therefore attempted to induce a duct-like phenotype in the striated duct-derived HSY cells by growing them on microcarrier beads coated with type I collagen. In Ca-containing medium cells grown on all substrates showed similar responses to ATP. In contrast, in Ca-free medium, [Ca2+]i rose only slightly in cells grown on beads relative to those on glass. This probably resulted from reduced IP3 production. Carbachol also induced a much smaller increase in [Ca2+]i and less IP3 production in cells grown on Cytodex-3. The HSY response to purinergic stimuli by an increase in [Ca2+]i and IP3 means that they can be used to study the metabotropic purinergic pathway. The impairment in the HSY responses grown on Cytodex-3 can be used to probe phosposinositol signal transduction in salivary cells.
