Abstract
Significant loss of pigmentation can increase visual disability, skin cancer risk, and psychosocial stress. Tyrosinase (TYR) catalyzes the first and rate-limiting step of melanin synthesis. Inhibitors of TYR are well established and are currently used in clinical settings; however, there is a dearth of direct activators of TYR. Here, using a human TYR construct, we developed high-throughput screening methods, in cell confirmatory assays employing 13C-tyrosine tracing, and computational analysis techniques, and identified ampyrone (4-aminoantipyrine) as a TYR activator. Ampyrone increased the in vitro catalytic activity of the human recombinant intra-melanosomal domain of TYR (hTYR) and its hypomorphic variant, Pro406Leu (P406L), a cause of oculocutaneous albinism type 1B (OCA1B). Moreover, ampyrone induced melanin synthesis in both wild-type and OCA1B human melanocytes, mouse OCA2 melanocytes, as well as 3-dimensional (3D) human skin cultures. Computational studies provided additional insight into the effects of direct TYR agonists on enzyme activity. Our results identified ampyrone as a lead candidate for TYR activation, potentially supporting the development of therapies for patients with genetic and acquired diseases of hypopigmentation.
Authors
Monika B. Dolinska, Yuhong A. Wang, Nathan P. Coussens, Vijay K. Kalaskar, Zuhal Eraslan, Samuel J. Grondin, Joseph Bonica, Sarah Toay, Matthew D. Hall, Min Shen, Matthew Boxer, Qiuying Chen, Steven S. Gross, Nabeel Attarwala, Yingyos Jittayasothorn, Ramakrisha P. Alur, Dhyanam Shukla, Robin Kee, Charles DeYoung, Cuilee Sha, David R. Adams, Stacie K. Loftus, Tiziana Cogliati, Yuri V. Sergeev, Jonathan H. Zippin, Brian P. Brooks
This file is in Adobe Acrobat (PDF) format. If you have not installed and configured the Adobe Acrobat Reader on your system.
Having trouble reading a PDF?
PDFs are designed to be printed out and read, but if you prefer to read them online, you may find it easier if you increase the view size to 125%.
Having trouble saving a PDF?
Many versions of the free Acrobat Reader do not allow Save. You must instead save the PDF from the JCI Online page you downloaded it from. PC users: Right-click on the Download link and choose the option that says something like "Save Link As...". Mac users should hold the mouse button down on the link to get these same options.
Having trouble printing a PDF?
- Try printing one page at a time or to a newer printer.
- Try saving the file to disk before printing rather than opening it "on the fly." This requires that you configure your browser to "Save" rather than "Launch Application" for the file type "application/pdf", and can usually be done in the "Helper Applications" options.
- Make sure you are using the latest version of Adobe's Acrobat Reader.
