Inhibition of prostatic smooth muscle contraction by the inhibitor of G protein-coupled receptor kinase 2/3, CMPD101

Yu, Qingfeng; Gratzke, Christian; Wang, Yiming; Herlemann, Annika; Strittmatter, Frank; Rutz, Beata; Stief, Christian G. und Hennenberg, Martin (2018): Inhibition of prostatic smooth muscle contraction by the inhibitor of G protein-coupled receptor kinase 2/3, CMPD101. In: European Journal of Pharmacology, Bd. 831: S. 9-19

Abstract

Alpha1-adrenoceptors induce prostate smooth muscle contraction, and hold a prominent role for pathophysiology and therapy of lower urinary tract symptoms in benign prostatic hyperplasia. G protein-coupled receptors are regulated by posttranslational regulation, including phosphorylation by G protein-coupled receptor kinases 2 and 3 (GRK2/3). Although posttranslational adrenoceptor regulation has been recently suggested to occur in the prostate, this is still marginally understood. With the newly developed CMPD101, a small molecule inhibitor with assumed specificity for GRK2/3 is now available. Here, we studied effects of CMPD101 on smooth muscle contraction of human prostate tissue. Electric field stimulation caused frequency-dependent contractions, which were inhibited concentration-dependently by CMPD101 (5 mu M, 50 mu M). 50 mu M of CMPD101 did not affect myosin light chain (MCL) phosphorylation or Rho kinase activity, and did not alter contractions induced by highmolar KCl. Noradrenaline, the alpha(1)-adrenoceptor agonist phenylephrine, endothelin-1, and the thromboxane A(2) analogue U46619 induced concentration-dependent contractions, which were inhibited by CMPD101 (50 mu M). CMPD101 ( 50 mu M) did not change phosphorylation of beta(2)-adrenoceptors or beta(2)-adrenergic relaxation of prostate strips. Molecular detection by Western blot and peroxidase staining suggested expression of GRK2 and GRK3 in human prostates. Double labeling in fluorescence staining confirmed that immunoreactivity for GRK2 and GRK3 was located to smooth muscle cells in the prostate stroma. In conclusion, CMPD101 inhibits adrenergic, neurogenic, and non-adrenergic smooth muscle contractions in the human prostate. Underlying mechanisms may be independent from GRK inhibition, and from inhibition of MLC kinase and Rho kinase. This may point to unknown properties of CMPD101.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Medizin
• Themengebiete: 600 Technik, Medizin, angewandte Wissenschaften > 610 Medizin und Gesundheit
• ISSN: 0014-2999
• Sprache: Englisch