Increased proliferation of human bladder smooth muscle cells is mediated by physiological cyclic stretch via the PI3K‑SGK1‑Kv1.3 pathway

Tian,Ye; Yue,Xuan; Luo,Deyi; Wazir,Romel; Wang,Jianzhong; Wu,Tao; Chen,Lin; Liao,Banghua; Wang,Kunjie

doi:10.3892/mmr.2013.1473

Increased proliferation of human bladder smooth muscle cells is mediated by physiological cyclic stretch via the PI3K‑SGK1‑Kv1.3 pathway

Authors:
- Ye Tian
- Xuan Yue
- Deyi Luo
- Romel Wazir
- Jianzhong Wang
- Tao Wu
- Lin Chen
- Banghua Liao
- Kunjie Wang
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Affiliations: Department of Urology, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China
Published online on: May 13, 2013 https://doi.org/10.3892/mmr.2013.1473
Pages: 294-298

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Abstract

It is well known that specific mechanical stimuli induce positive changes in the physiological function and status of a number of cell types. However, an in‑depth understanding of the application of mechanical forces has yet to be developed. The aim of the present study was to explore the optimal elongation and frequency of stretch‑induced proliferation of human bladder smooth muscle cells (HBSMCs) and to investigate the mechanism involved in this process. HBSMCs were seeded in a silicone membrane and subjected to cyclic stretch of 2.5, 5, 10 and 15% equibiaxial elongation at frequencies of 0.05, 0.1, 0.2, 0.5 and 1 Hz, respectively. Bromodeoxyuridine (BrdU) assays were used to detect the proliferative activity of each group. To further determine the mechanism of the cell proliferation process triggered by physiological cyclic stretch, the expression of PI3K/SGK1/Akt/Kv1.3 was investigated at the transcriptional and translational levels by RT‑PCR and western blot analysis, respectively. Optimal physiological stretch was established as 5% elongation at a frequency of 0.1 Hz, whereby HBSMCs revealed a marked increase in proliferative activity compared with the other groups, including the non‑stretched group, which served as the control (P<0.05). The expression of PI3K/SGK1/Kv1.3; however, not Akt, were upregulated by cyclic stretch as compared with the control group. When separately treated with inhibitors of SGK1 and Kv1.3, increased stretch‑induced proliferation was largely eliminated. These results markedly indicate that cyclic stretch induces the proliferation of HBSMCs and the PI3K‑SGK1‑Kv1.3 pathway is involved in this process, either fully or at least partially, rather than its related pathway, PI3K‑Akt.

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1	Fraser M, Thomas DF, Pitt E, Harnden P, Trejdosiewicz LK and Southgate J: A surgical model of composite cystoplasty with cultured urothelial cells: a controlled study of gross outcome and urothelial phenotype. BJU Int. 93:609–616. 2004. View Article : Google Scholar : PubMed/NCBI
2	Southgate J, Gross W, Eardley I, Thomas DF and Trejdosiewicz LK: Bladder reconstruction - from cells to materials. Proc Inst Mech Eng H. 217:311–316. 2003. View Article : Google Scholar : PubMed/NCBI
3	Zhang Y, Frimberger D, Cheng EY, Lin HK and Kropp BP: Challenges in a larger bladder replacement with cell-seeded and unseeded small intestinal submucosa grafts in a subtotal cystectomy model. BJU Int. 98:1100–1105. 2006. View Article : Google Scholar
4	Lee DY, Yeh CR, Chang SF, Lee PL, Chien S, Cheng CK and Chiu JJ: Integrin-mediated expression of bone formation-related genes in osteoblast-like cells in response to fluid shear stress: roles of extracellular matrix, Shc and mitogen-activated protein kinase. J Bone Miner Res. 23:1140–1149. 2008. View Article : Google Scholar
5	Liu D, Genetos DC, Shao Y, Geist DJ, Li J, Ke HZ, Turner CH and Duncan RL: Activation of extracellular-signal regulated kinase (ERK1/2) by fluid shear is Ca(2⁺)- and ATP-dependent in MC3T3-E1 osteoblasts. Bone. 42:644–652. 2008. View Article : Google Scholar : PubMed/NCBI
6	Lee AA, Graham DA, Dela CS, Ratcliffe A and Karlon WJ: Fluid shear stress-induced alignment of cultured vascular smooth muscle cells. J Biomech Eng. 124:37–43. 2002. View Article : Google Scholar : PubMed/NCBI
7	Wei X, Li DB, Xu F, Wang Y, Zhu YC, Li H and Wang KJ: A novel bioreactor to simulate urinary bladder mechanical properties and compliance for bladder functional tissue engineering. Chin Med J (Engl). 124:568–573. 2011.PubMed/NCBI
8	Ramachandran A, Gong EM, Pelton K, Ranpura SA, Mulone M, Seth A, Gomez P 3rd and Adam RM: FosB regulates stretch-induced expression of extracellular matrix proteins in smooth muscle. Am J Pathol. 179:2977–2989. 2011. View Article : Google Scholar : PubMed/NCBI
9	Farhat WA and Yeger H: Does mechanical stimulation have any role in urinary bladder tissue engineering? World J Urol. 26:301–305. 2008. View Article : Google Scholar : PubMed/NCBI
10	Chen L, Wei TQ, Wang Y, Zhang J, Li H and Wang KJ: Simulated bladder pressure stimulates human bladder smooth muscle cell proliferation via the PI3K/SGK1 signaling pathway. J Urol. 188:661–667. 2012. View Article : Google Scholar : PubMed/NCBI
11	Wu T, Chen L, Wei TQ, Wang Y, Xu F and Wang K: Effect of cyclic hydrodynamic pressure-induced proliferation of human bladder smooth muscle through Ras-related C3 botulinum toxin substrate 1, mitogen-activated protein kinase kinase 1/2 and extracellular regulated protein kinases 1/2. Int J Urol. 19:867–874. 2012. View Article : Google Scholar
12	Brivanlou AH and Darnell JJ: Signal transduction and the control of gene expression. Science. 295:813–818. 2002. View Article : Google Scholar : PubMed/NCBI
13	Elbadawi A: Pathology and pathophysiology of detrusor in incontinence. Urol Clin North Am. 22:499–512. 1995.PubMed/NCBI
14	el-Feky H, Mangoud AM, Aly MA, Eissa MH, Abdel-Wahab RM, Kamhawy M, Ghobish A, Sabry AH, el Zayyat EA and Morsy TA: Detrusor morphology and pathology in relation to bladder outflow obstruction in bilharzial patients. J Egypt Soc Parasitol. 21:699–706. 1991.PubMed/NCBI
15	Cerruto MA, Asimakopoulos AD, Artibani W, Del Popolo G, La Martina M, Carone R and Finazzi-Agrò E: Insight into new potential targets for the treatment of overactive bladder and detrusor overactivity. Urol Int. 89:1–8. 2012. View Article : Google Scholar : PubMed/NCBI
16	Webster MK, Goya L, Ge Y, Maiyar AC and Firestone GL: Characterization of sgk, a novel member of the serine/threonine protein kinase gene family which is transcriptionally induced by glucocorticoids and serum. Mol Cell Biol. 13:2031–2040. 1993.PubMed/NCBI
17	Park J, Leong ML, Buse P, Maiyar AC, Firestone GL and Hemmings BA: Serum and glucocorticoid-inducible kinase (SGK) is a target of the PI 3-kinase-stimulated signaling pathway. EMBO J. 18:3024–3033. 1999. View Article : Google Scholar : PubMed/NCBI
18	Kobayashi T and Cohen P: Activation of serum- and glucocorticoid-regulated protein kinase by agonists that activate phosphatidylinositide 3-kinase is mediated by 3-phosphoinositide-dependent protein kinase-1 (PDK1) and PDK2. Biochem J. 339:319–328. 1999. View Article : Google Scholar
19	Lang F, Böhmer C, Palmada M, Seebohm G, Strutz-Seebohm N and Vallon V: (Patho)physiological significance of the serum- and glucocorticoid-inducible kinase isoforms. Physiol Rev. 86:1151–1178. 2006. View Article : Google Scholar : PubMed/NCBI
20	Liu G, Hitomi H, Hosomi N, Lei B, Nakano D, Deguchi K, Mori H, Masaki T, Ma H, Griendling KK and Nishiyama A: Mechanical stretch augments insulin-induced vascular smooth muscle cell proliferation by insulin-like growth factor-1 receptor. Exp Cell Res. 317:2420–2428. 2011. View Article : Google Scholar : PubMed/NCBI
21	Stover J and Nagatomi J: Cyclic pressure stimulates DNA synthesis through the PI3K/AKT signaling pathway in rat bladder smooth muscle cells. Ann Biomed Eng. 35:1585–1594. 2007. View Article : Google Scholar : PubMed/NCBI
22	Sakoda H, Gotoh Y, Katagiri H, Kurokawa M, Ono H, Onishi Y, Anai M, Ogihara T, Fujishiro M, Fukushima Y, Abe M, Shojima N, Kikuchi M, Oka Y, Hirai H and Asano T: Differing roles of AKT and serum- and glucocorticoid-regulated kinase in glucose metabolism, DNA synthesis and oncogenic activity. J Biol Chem. 278:25802–25807. 2003. View Article : Google Scholar : PubMed/NCBI
23	Gamper N, Fillon S, Huber SM, Feng Y, Kobayashi T, Cohen P and Lang F: IGF-1 up-regulates K⁺ channels via PI3-kinase, PDK1 and SGK1. Pflugers Arch. 443:625–634. 2002.PubMed/NCBI
24	Cheng J, Wang Y, Ma Y, Chan BT, Yang M, Liang A, Zhang L, Li H and Du J: The mechanical stress-activated serum-, glucocorticoid-regulated kinase 1 contributes to neointima formation in vein grafts. Circ Res. 107:1265–1274. 2010. View Article : Google Scholar : PubMed/NCBI
25	Wonderlin WF and Strobl JS: Potassium channels, proliferation and G1 progression. J Membr Biol. 154:91–107. 1996. View Article : Google Scholar : PubMed/NCBI
26	Pardo LA: Voltage-gated potassium channels in cell proliferation. Physiology (Bethesda). 19:285–292. 2004. View Article : Google Scholar : PubMed/NCBI
27	Jackson WF: KV1.3: a new therapeutic target to control vascular smooth muscle cell proliferation. Arterioscler Thromb Vasc Biol. 30:1073–1074. 2010. View Article : Google Scholar : PubMed/NCBI
28	Atala A: Tissue engineering of human bladder. Br Med Bull. 97:81–104. 2011. View Article : Google Scholar
29	Lang F, Bohmer C, Palmada M, Seebohm G, Strutz-Seebohm N and Vallon V: (Patho)physiological significance of the serum- and glucocorticoid-inducible kinase isoforms. Physiol Rev. 86:1151–1178. 2006. View Article : Google Scholar : PubMed/NCBI
30	Kahl CR and Means AR: Regulation of cell cycle progression by calcium/calmodulin-dependent pathways. Endocr Rev. 24:719–736. 2003. View Article : Google Scholar : PubMed/NCBI
31	Parekh AB and Penner R: Store depletion and calcium influx. Physiol Rev. 77:901–930. 1997.PubMed/NCBI
32	Berridge MJ, Lipp P and Bootman MD: The versatility and universality of calcium signalling. Nat Rev Mol Cell Biol. 1:11–21. 2000. View Article : Google Scholar : PubMed/NCBI
33	Means AR: Calcium, calmodulin and cell cycle regulation. FEBS Lett. 347:1–4. 1994. View Article : Google Scholar : PubMed/NCBI
34	Allard D, Figg N, Bennett MR and Littlewood TD: AKT regulates the survival of vascular smooth muscle cells via inhibition of FoxO3a and GSK3. J Biol Chem. 283:19739–19747. 2008. View Article : Google Scholar : PubMed/NCBI
35	Wu W, Chaudhuri S, Brickley DR, Pang D, Karrison T and Conzen SD: Microarray analysis reveals glucocorticoid-regulated survival genes that are associated with inhibition of apoptosis in breast epithelial cells. Cancer Res. 64:1757–1764. 2004. View Article : Google Scholar : PubMed/NCBI