The basolateral localization of OCTs has also been observed in hepatocytes and kidney proximal tubule [9], where the transcellular movement of organic cations has been shown to depend upon the combined action of electrogenic OCT-mediated uptake at the basolateral side and the apical efflux supported by the pump em ABCB1 /em /P-gp and MATEs [5]. OCTs and OCTNs expression, along with that of Amino acid Transporter B0,+ (ATB0,+)transporter, was determined by measuring the number of mRNA molecules through quantitative Polymerase Chain Reaction (qPCR). The conversation of the transporters with bronchodilators was also assessed. Results spotlight significant differences between Pomalidomide-C2-NH2 hydrochloride Calu-3 cells and EpiAirway?, since, in the latter, OCTs are active only around the basolateral membrane where they interact with the bronchodilator ipratropium. No activity of OCTs is usually detectable at the apical side; there, the most abundant carrier is usually, instead, (OCT1), (OCT3), (ATB0,+) 1. Introduction Human transporters belonging to the solute carrier family 22A (SLC22A) play a central role in physiology, pharmacology, and toxicology because of the broad spectrum of endogenous metabolites, drugs, and toxins that they can move across cell plasma membranes [1,2]. According to a simplified classification based on the electric nature of the substrates, the human SLC22A family includes Organic cation transporters (OCTs: OCT1, OCT2, and OCT3) that operate as electrogenic Pomalidomide-C2-NH2 hydrochloride uniporters for organic Rabbit Polyclonal to FPRL2 cations, the so-called Novel organic cation transporters (OCTNs) mediating Na+-cotransport of selected zwitterions, and Organic Anions Transporters (OATs), that physiologically work as organic anion exchangers [3]. For the transepithelial secretion of organic cations, OCTs are frequently paired to the obligatory exchangers multidrug and toxin extruders (MATEs) belonging to the SLC47 family [4], with OCTs typically operating the basolateral uptake of organic cations and MATEs responsible for the apical efflux [5,6]. All three OCTs transport endogenous compounds, such as monoamine neurotransmitters, carnitine derivatives, and creatinine, as well as several drugs, and model substrates for OCTs are 1-methyl-4-phenylpyridinium (MPP+) and tetraethylammonium (TEA) [3,7]. These transporters display a characteristic multi-selectivity with broadly overlapping sites of expression in many tissues such as liver, kidney, heart, skeletal muscle, placenta, lung, brain, immune system [8,9], as well as in the whole gastrointestinal tract [10]. Studies concerning OCTs transporters have mainly focused on hepatocytes and kidney proximal tubule, owing to the key role of these tissues in Pomalidomide-C2-NH2 hydrochloride the metabolism of endogenous compounds and xenobiotics and in the excretion of water-soluble drugs and derivatives [5]. As far as the lung is concerned, the physiological role of OCT transporters is usually thus far incompletely comprehended, despite the fact that it is known that OCTs mediate the transport of inhaled drugs [11,12]. The expression and activity of OCTs has been addressed in various cell models representative of different respiratory tracts [13,14,15]. To this concern, in a previous study, we focused on OCTs in respiratory epithelial cell lines of human origin, i.e., in Calu-3, 16HBE14o-, NCl-H441, and BEAS-2B [16], and highlighted significant differences in the expression of the transporters among the cell models. Indeed, while A549 and NCl-H441 were endowed with the activity of the sole OCT3 and OCT1 respectively, both transporters were operative in Calu-3 and BEAS-2B. OCT2 transporter was not detected in any of the cell lines employed. The major concern raised from that and comparable studies is usually that they all employed transfected or immortal cell lines as models, and the possibility exists that their biological features may differ from those of primary differentiated cells. Thus, the need for a reliable model of normal respiratory epithelium in vitro is usually urgent for research concerning drug absorption and disposition in the airways. Recently, innovative culture systems of human respiratory and nasal epithelial cells, such as the EpiAirway? (MatTek Corporation) and MucilAir? (Epithelix) systems, have been developed [6]. Due to their composition and structure, these models, composed of well-differentiated ciliated and goblet Pomalidomide-C2-NH2 hydrochloride cells, properly reflect the phenotype of barriers in vivo [17], thus appearing useful tools for studies of drug permeability. Since no information is usually available about OCTs in this cell system, the aim of Pomalidomide-C2-NH2 hydrochloride the present study is usually to characterize their expression and activity in EpiAirway?. 2. Materials and Methods 2.1. Cell Cultures EpiAirway? tissues (AIR-200-PE6.5), supplied by MatTek Lifesciences (Ashland, MA, USA), were used. Cultured on microporous membrane inserts at the airCliquid.