Expression of the mechanosensitive 2PK+ channel TREK-1 in human osteoblasts.
TREK-1 is a mechanosensitive member of the two-pore domain potassium channel family (2PK+) that is also sensitive to lipids, free fatty acids (including arachidonic acid), temperature, intracellular pH, and a range of clinically relevant compounds including volatile anaesthetics. TREK-1 is known to be expressed at high levels in excitable tissues, such as the nervous system, the heart and smooth muscle, where it is believed to play a prominent role in controlling resting cell membrane potential and electrical excitability. In this report, we use RT-PCR, Western blotting and immunohistochemistry to confirm that human derived osteoblasts and MG63 cells express TREK-1 mRNA and protein. In addition, we show gene expression of TREK2c and TRAAK channels. Furthermore, whole cell patch clamp electrophysiology demonstrates that these cells express a spontaneously active, outwardly rectifying potassium "background leak" current that shares many similarities to TREK-1. The outward current is largely insensitive to TEA and Ba2+, and is sensitive to application of lysophosphatidylcholine (LPC). In addition, blocking TREK-1 channel activity is shown to upregulate bone cell proliferation. It is concluded that human osteoblasts functionally express TREK-1 and that these channels contribute, at least in part, to the resting membrane potential of human osteoblast cells. We hypothesise a possible role for TREK-1 in mechanotransduction, leading to bone remodelling.
Hughes
Steven
S
Institute of Science and Technology in Medicine, Keele University Medical School, Hartshill Campus, Thornburrow Drive, Hartshill, Stoke-on-Trent, United Kingdom.
Magnay
Julia
J
Foreman
Megan
M
Publicover
Stephen J
SJ
Dobson
Jon P
JP
El Haj
Alicia J
AJ
D000293:Adolescent; D000328:Adult; D000818:Animals; D019556:COS Cells; D049109:Cell Proliferation; D002648:Child; D002522:Chlorocebus aethiops; D006801:Humans; D007150:Immunohistochemistry; D008244:Lysophosphatidylcholines / Q000494:pharmacology*; D008564:Membrane Potentials / Q000187:drug effects; D008875:Middle Aged; D010006:Osteoblasts / Q000378:metabolism* / Q000502:physiology*; D016133:Polymerase Chain Reaction; D026902:Potassium Channel Blockers; D024683:Potassium Channels, Tandem Pore Domain / Q000378:metabolism*; D014162:Transfection
D008244:Lysophosphatidylcholines; D026902:Potassium Channel Blockers; D024683:Potassium Channels, Tandem Pore Domain; C103742:potassium channel protein TREK-1