Fabry disease is a glycosphingolipidosis caused by deficient activity of α-galactosidase A; it is one of a few diseases that are associated with priapism, an abnormal prolonged erection of the penis. The goal of this study was to investigate the pathogenesis of Fabry disease-associated priapism in a mouse model of the disease. We found that Fabry mice develop late-onset priapism. Neuronal nitric oxide synthase (nNOS), which was predominantly present as the 120-kDa N-terminus-truncated form, was significantly upregulated in the penis of 18-month-old Fabry mice compared to wild type controls (~fivefold). Endothelial NOS (eNOS) was also upregulated (~twofold). NO level in penile tissues of Fabry mice was significantly higher than wild type controls at 18 months. Gene transfer-mediated enzyme replacement therapy reversed abnormal nNOS expression in the Fabry mouse penis. The penile nNOS level was restored by antiandrogen treatment, suggesting that hyperactive androgen receptor signaling in Fabry mice may contribute to nNOS upregulation. However, the phosphodiesterase-5A expression level and the adenosine content in the penis, which are known to play roles in the development of priapism in other etiologies, were unchanged in Fabry mice. In conclusion, these data suggested that increased nNOS (and probably eNOS) content and the consequential elevated NO production and high arterial blood flow in the penis may be the underlying mechanism of priapism in Fabry mice. Furthermore, in combination with previous findings, this study suggested that regulation of NOS expression is susceptible to α-galactosidase A deficiency, and this may represent a general pathogenic mechanism of Fabry vasculopathy.
Journal of inherited metabolic disease. 2017 Nov 06 [Epub]
Xing-Li Meng, Erland Arning, Mary Wight-Carter, Taniqua S Day, Siamak Jabbarzadeh-Tabrizi, Shuyuan Chen, Robin J Ziegler, Teodoro Bottiglieri, Jay W Schneider, Seng H Cheng, Raphael Schiffmann, Jin-Song Shen
Institute of Metabolic Disease, Baylor Research Institute, 3812 Elm Street, Dallas, TX, 75226, USA., Animal Resources Center Diagnostic Laboratory, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390, USA., Baylor Research Institute, Dallas, TX, 75226, USA., Sanofi, 49 New York Avenue, Framingham, MA, 01701, USA., Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390, USA., Institute of Metabolic Disease, Baylor Research Institute, 3812 Elm Street, Dallas, TX, 75226, USA. .