• Biomolecules & Therapeutics
• /
• v.24 no.3
• /
• pp.252-259
• /
• 2016

Neuropathic pain is a complex state showing increased pain response with dysfunctional inhibitory neurotransmission. The TREK family, one of the two pore domain $K^+$ (K2P) channel subgroups were focused among various mechanisms of neuropathic pain. These channels influence neuronal excitability and are thought to be related in mechano/thermosensation. However, only a little is known about the expression and role of TREK-1 and TREK-2, in neuropathic pain. It is performed to know whether TREK-1 and/or 2 are positively related in dorsal root ganglion (DRG) of a mouse neuropathic pain model, the chronic constriction injury (CCI) model. Following this purpose, Reverse Transcription Polymerase Chain Reaction (RT-PCR) and western blot analyses were performed using mouse DRG of CCI model and compared to the sham surgery group. Immunofluorescence staining of isolectin-B4 (IB4) and TREK were performed. Electrophysiological recordings of single channel currents were analyzed to obtain the information about the channel. Interactions with known TREK activators were tested to confirm the expression. While both TREK-1 and TREK-2 mRNA were significantly overexpressed in DRG of CCI mice, only TREK-1 showed significant increase (~9 fold) in western blot analysis. The TREK-1-like channel recorded in DRG neurons of the CCI mouse showed similar current-voltage relationship and conductance to TREK-1. It was easily activated by low pH solution (pH 6.3), negative pressure, and riluzole. Immunofluorescence images showed the expression of TREK-1 was stronger compared to TREK-2 on IB4 positive neurons. These results suggest that modulation of the TREK-1 channel may have beneficial analgesic effects in neuropathic pain patients.

• Journal of Embryo Transfer
• /
• v.26 no.3
• /
• pp.209-214
• /
• 2011

Endometrium undergoing hormonal change plays important roles in preparation for implantation, fetal growth, and well-being. During pregnancy, cellular remodeling and hormonal changes in endometrium could change two-pore domain K$^+$ channel (K$_{2P}$) expression. This study was performed to identify whether K$_{2P}$ channel expression is changed in endometrium of pregnant Korean cattle, and whether the expression level is modulated by progesterone treatment. We investigated changes in the mRNA and protein expressions of K$_{2P}$ channel in pregnant endometrium using RT-PCR and Western blot analyses. The expression levels of all K$_{2P}$ channel mRNAs tested in this study, except that of TREK-1, were changed in the pregnant endometrium. mRNA levels of TASK-3 and TRAAK were significantly down-regulated, whereas those of TREK-2 and TRESK were up-regulated in the pregnant endometrium. In parallel with the RT-PCR results, Western blot analysis revealed up-regulations of TREK-2 (7.9-fold) and TRESK (2-fold) proteins levels in the pregnant endometrium. In addition, TREK-2 and TRESK protein levels were up-regulated in bovine endometrial cells by progesterone treatment (10 ${\mu}g$/ml). From these results, we suggest that the up-regulation of TREK-2 and TRESK by progesterone may contribute to the regulation of physiological changes during pregnancy.

• Journal of Embryo Transfer
• /
• v.22 no.3
• /
• pp.149-154
• /
• 2007

Endometrial cells play important roles in implantation and during pregnancy. This study was carried out to identify whether two-pore domain $K^+\;(K_{2P})$ channels are expressed in endometrial cells of Korean cattle. $K_{2P}$ channels set the resting membrane potential of many kinds of neuronal cells in the central and peripheral nervous systems. RT-PCR data showed that TASK-1, TASK-3, TREK-1, TREK-2, and TRAAK were expressed in bovine endometrial cells, and the mRNA expression levels were similar between endometrial cells with or without endometritis. The protein expression was confirmed by using commercially available polyclonal antibodies (TASK-3, TREK-1, TREK-2, and TRAAK). TASK-3 and TREK-1 were expressed in all area of endometrial cells including nuclei, while TREK-2 and TRAAK were expressed in all area of cells except nuclei. These results demonstrate for the first time the presence of $K_{2P}$ channel in endometrial cells of Korean cattle.

• The Korean Journal of Physiology and Pharmacology
• /
• v.17 no.6
• /
• pp.511-516
• /
• 2013

Bladder cancer is the seventh most common cancer in men that smoke, and the incidence of disease increases with age. The mechanism of occurrence has not yet been established. Potassium channels have been linked with cell proliferation. Some two-pore domain $K^+$ channels (K2P), such as TASK3 and TREK1, have recently been shown to be overexpressed in cancer cells. Here we focused on the relationship between cell growth and the mechanosensitive K2P channel, TREK2, in the human bladder cancer cell line, 253J. We confirmed that TREK2 was expressed in bladder cancer cell lines by Western blot and quantitative real-time PCR. Using the patch-clamp technique, the mechanosensitive TREK2 channel was recorded in the presence of symmetrical 150 mM KCl solutions. In 253J cells, the TREK2 channel was activated by polyunsaturated fatty acids, intracellular acidosis at -60 mV and mechanical stretch at -40 mV or 40 mV. Furthermore, small interfering RNA (siRNA)-mediated TREK2 knockdown resulted in a slight depolarization from $-19.9mV{\pm}0.8$ (n=116) to $-8.5mV{\pm}1.4$ (n=74) and decreased proliferation of 253J cells, compared to negative control siRNA. 253J cells treated with TREK2 siRNA showed a significant increase in the expression of cell cycle boundary proteins p21 and p53 and also a remarkable decrease in protein expression of cyclins D1 and D3. Taken together, the TREK2 channel is present in bladder cancer cell lines and may, at least in part, contribute to cell cycle-dependent growth.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.3
• /
• pp.1964-1971
• /
• 2015

Human bone marrow or human umbilical cord vein derived-mesenchymal stem cells (hBM-MSCs or hUC-MSCs) have known as a potentially useful cell type for clinical therapeutic applications. We investigated two-pore domain potassium (K2P) channels in these cells. K2P channels play a major role in setting the resting membrane potential in many cell types. Among them, TREK1 is targets of hydrogen, hypoxia, polyunsaturated fatty acids, antidepressant, and neurotransmitters. We investigated whether hBM-MSCs and hUC-MSCs express functional TREK1 channel using RT-PCR analysis and patch clamp technique. Potassium channel with a single channel conductance of 100 pS was found in hUC-MSCs and BM-MSCs and the channel was activated by membrane stretch (-5 mmHg ~ -15 mmHg), arachidonic acid ($10{\mu}M$) and intracellular acidosis (pH 6.0). These electrophysiological properties were similar to those of TREK1. Our results suggest that TREK1 is functionally present in hBM-MSCs and hUC-MSCs, where they contribute to its resting membrane potential.