Expression of the high-affinity choline transporter CHT1 in epithelia.
Uptake of choline by the high-affinity choline transporter CHT1 is the rate-limiting step in neuronal acetylcholine (ACh) synthesis. Here, we investigated by RT-PCR, in-situ hybridisation, immunohistochemistry, and Western blotting whether CHT1 is also expressed in cholinergic epithelia. CHT1-mRNA and -protein were detected in keratinocytes of human skin, rat skin and tongue, the human keratinocyte cell line HaCaT, and the ciliated cells of the rat tracheal epithelium. Immunohistochemically, CHT1 was predominantly localized to the epithelial cell membranes, in case of ciliated tracheal cells it was restricted to the apical membrane. This is the first study to demonstrate the expression of CHT1 in non-neuronal cells. The close apposition of CHT1 to reported sites of localization of choline acetyltransferase in these cells is strongly in favour of ACh synthesis being fuelled by choline uptake via CHT1 in these epithelia.
Pfeil
Uwe
U
Institute for Anatomy and Cell Biology, Justus-Liebig-University, Aulweg 123, 35385 Giessen, Germany.
Haberberger
Rainer V
RV
Lips
Katrin S
KS
Eberling
Lars
L
Grau
Veronika
V
Kummer
Wolfgang
W
D000818:Animals; D002799:Cholinergic Fibers / Q000378:metabolism; D002923:Cilia / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D026901:Membrane Transport Proteins / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014132:Trachea / Q000166:cytology / Q000187:drug effects / Q000378:metabolism
D026901:Membrane Transport Proteins; D012333:RNA, Messenger; C065637:choline transporter