Choi Joongwon, Han Deok H, Chae Mee R, Sung Hyun H, Kang Su J, Shin Jimin, Lee Sung W
Department of Urology, VHS Medical Center, Seoul, Republic of Korea.
Department of Urology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
Andrology. 2021 May;9(3):933-943. doi: 10.1111/andr.12967. Epub 2021 Feb 1.
Relaxation of prostate smooth muscle tone is a key strategy for the medical treatment of lower urinary tract symptoms (LUTS) in men. However, potassium channel's physiological role inhuman prostatic smooth muscle (HPrSM) has yet to be determined.
In this study, we examined the molecular characteristics and physiological roles of Kv7 channels in HPrSM.
The expressions of KCNQ1-5 (Kv7 channel pore-forming α-subunits) and KCNE1-5 (β-regulatory subunits) isoforms in HPrSM were examined using real-time PCR. The relaxation effect of ML213 was investigated by cumulatively adding ML213 to the prostate strips. Kv7 currents were recorded using an amphotericin-B perforated patch-clamp technique.
In HPrSM cells, KCNQ4, KCNQ5, and KCNE4 isoforms were predominantly expressed, while KCNQ1, KCNQ5, and KCNE3 isoforms were the most abundantly expressed in human prostatic tissues. Western blot analysis revealed the protein expression of the Kv7.1, 7.4, and 7.5 channel subtypes in human prostate tissues (n = 3). ML213 (an activator of Kv7.2/7.4/7.5) induced the concentration-dependent relaxation of HPrSM strips (n = 15, p = 0.001), and this effect was attenuated by pretreatment with XE991 (a Kv7.1-7.5 blocker). In electrophysiology studies, ML213 significantly increased the amplitude of whole-cell Kv7 currents in HPrSM cells. ML213-induced outward currents were greater than retigabine (a Kv7.2-7.5 channel activator). The subsequent addition of XE991 completely inhibited the ML213-induced currents (n = 9, p < 0.01 vs. ML213). ML213 hyperpolarized the HPrSM cell membrane potential and was fully reversed by XE991. In situ PLA revealed the colocalization of heteromeric KV7.4/KV7.5 channels in HPrSM cells.
Our findings suggest that Kv7.4 and 7.5 channels in prostatic smooth muscle play a critical role in the regulation of HPrSM tone and that Kv7 channel subtypes may be novel therapeutic targets for the treatment of LUTS associated with BPH.
前列腺平滑肌张力的松弛是男性下尿路症状（LUTS）医学治疗的关键策略。然而，钾通道在人前列腺平滑肌（HPrSM）中的生理作用尚未确定。
在本研究中，我们研究了Kv7通道在HPrSM中的分子特征和生理作用。
采用实时PCR检测HPrSM中KCNQ1 - 5（Kv7通道形成孔的α亚基）和KCNE1 - 5（β调节亚基）亚型的表达。通过向前列腺条带中累积添加ML213来研究其舒张作用。使用两性霉素B穿孔膜片钳技术记录Kv7电流。
在HPrSM细胞中，KCNQ4、KCNQ5和KCNE4亚型主要表达，而KCNQ1、KCNQ5和KCNE3亚型在人前列腺组织中表达最为丰富。蛋白质印迹分析显示人前列腺组织（n = 3）中Kv7.1、7.4和7.5通道亚型的蛋白表达。ML213（一种Kv7.2/7.4/7.5激活剂）诱导HPrSM条带浓度依赖性舒张（n = 15，p = 0.001），并且这种作用被XE991（一种Kv7.1 - 7.5阻滞剂）预处理减弱。在电生理学研究中，ML213显著增加HPrSM细胞中全细胞Kv7电流的幅度。ML213诱导的外向电流大于瑞替加滨（一种Kv7.2 - 7.5通道激活剂）。随后添加XE991完全抑制了ML213诱导的电流（n = 9，与ML213相比，p < 0.01）。ML213使HPrSM细胞膜电位超极化，并被XE991完全逆转。原位PLA显示HPrSM细胞中异源KV7.4/KV7.5通道的共定位。
我们的研究结果表明，前列腺平滑肌中的Kv7.4和7.5通道在调节HPrSM张力中起关键作用，并且Kv7通道亚型可能是治疗与良性前列腺增生相关的LUTS的新型治疗靶点。
