Functional analysis of human olfactory receptors with a high basal activity using LNCaP cell line

Abstract

Humans use a family of more than 400 olfactory receptors (ORs) to detect odorants. However, deorphanization of ORs is a critical issue because the functional properties of more than 80% of ORs remain unknown, thus, hampering our understanding of the relationship between receptor function and perception. HEK293 cells are the most commonly used heterologous expression system to determine the function of a given OR; however, they cannot functionally express a majority of ORs probably due to a lack of factor(s) required in cells in which ORs function endogenously. Interestingly, ORs have been known to be expressed in a variety of cells outside the nose and play critical physiological roles. These findings prompted us to test the capacity of cells to functionally express a specific repertoire of ORs. In this study, we selected three cell lines that endogenously express functional ORs. We demonstrated that human prostate carcinoma (LNCaP) cell lines successfully identified novel ligands for ORs that were not recognized when expressed in HEK293 cells. Further experiments suggested that the LNCaP cell line was effective for functional expression of ORs, especially with a high basal activity, which impeded the sensitive detection of ligand-mediated activity of ORs. This report provides an efficient functional assay system for a specific repertoire of ORs that cannot be characterized in current cell systems.

An efficient behavioral screening platform classifies natural products and other chemical cues according to their chemosensory valence inC. elegans

“…Our finding that acetophenone attracts wild-type C. elegans and repels tax-4 mutants (Figs 6, 7) implies that there are also at least two acetophenone receptors in C. elegans. Three of these plant SMs, anisole, camphor, and cinnamyl alcohol, also activate human olfactory GPCRs [88][89][90]. The weak repellents, ellagic acid and methyl palmitate, activate human GPR35 and the CB1/2 receptors [91,92], respectively, and oleanolic acid and ursolic acid both activate GPBAR1 [93,94].…”

Olfactory Receptors as an Emerging Chemical Sensing Scaffold

“… 80 More recently, the ability of ORs to functionally express ectopically has led to the use of human prostate carcinoma to generate OR-based sensors. 81 …”

“…Alternative cell lines include HeLA/Olf, where cAMP increases results in a Ca 2+ influx that can be measure via fluorescence . More recently, the ability of ORs to functionally express ectopically has led to the use of human prostate carcinoma to generate OR-based sensors …”

“…80 More recently, the ability of ORs to functionally express ectopically has led to the use of human prostate carcinoma to generate OR-based sensors. 81 A major application of OR-based sensors in mammalian cells has been OR deorphanization, with much of our knowledge about OR-ligand pairs coming from these assays. Deorphanization of ORs has a generally low hit rate.…”

Diverse yet selective tuning of an odorant receptor for sensing four classes of musk compounds

“…The sequence information of human ORs used in this study was reported previously 10,40 . Genes coding human ORs, trace amine-associated receptors (TAARs), and vomeronasal receptors type I (VN1R1s) were ampli ed from human genomic DNA (Promega, Madison, WI, USA).…”