Gene Expression in Rat Lacrimal Gland Duct Cells Collected Using Laser Capture Microdissection: Evidence for K⁺Secretion by Duct Cells

Abstract

Laser capture microdissection in conjunction with gene expression analysis provides an excellent approach for studying lacrimal gland duct cells about which relatively little is known at the molecular level. As demonstrated in a proposed model, the polarized expression of transporters and channels on lacrimal gland duct membranes is consistent with the hypothesis that duct cells secrete the relatively high K+ in lacrimal fluid.

Functional and molecular characterization of multiple K–Cl cotransporter isoforms in corneal epithelial cells

“…The more rapid RVD response by HCEC than in RCEC, could be attributed to higher KCC1 expression levels. These results validate that-as in many other cell types (Adragna et al, 2006;Adragna et al, 2004;Gillen et al, 1996;Ubels et al, 2006)-KCC1 is the "house-keeping" isoform, involved in maintenance of steady-state ionic homeostasis as well as CEC volume regulation.…”

Role of transmembrane chloride transporters in the fluid secretion of lacrimal gland duct cells

“…Ubels and colleagues introduced the laser capture microdissection technique in LG research to perform gene expression studies on collected duct cells from frozen rat LG sections (11). Numerous genes coding basolateral-to-apical K + secretion-related transport proteins were found to be highly expressed in duct cells compared to acinar cells.…”

“…Their work provided indirect evidence that coupled transport of Na + and Cl -is important in LG fluid secretion. Experimental evidence was found for expression of NKCC1 on the basolateral membranes of LG duct cells of rat, rabbit and mouse (11,15,16).…”

“…Despite of these clinical observations role of CFTR in production of preocular tear film is only partially investigated and its functional involvement in LG secretion is unknown. Accumulating evidences from rat and rabbit LG gene expression studies demonstrated the predominant expression of CFTR in LG duct cells (11,15,26). These studies were mostly descriptive without exploring the functional aspect of CFTR in LG secretion.…”

Physiological and pathophysiological investigation of lacrimal and pancreatic ductal epithelial cells

“…Ca 2+ and cAMP signaling pathways in activation of epithelial fluid and electrolyte secretion are well studied in different gland types such as pancreas and salivary gland, however we are lacking of information about LG secretory functions. Based on findings from our laboratory and gene expression studies a scematic figure of lacrimal gland ductal secretion was designed ( Figure 1B) [14,[45][46][47][48].…”