Nicholas A Delamere

Nicholas A Delamere

Department Head, Physiology
Professor, Physiology
Professor, Ophthalmology
Member of the Graduate Faculty
Professor, BIO5 Institute
Primary Department
Department Affiliations
Contact
(520) 626-6425

Research Interest

Nicholas Delamere, Ph.D., studies how ocular pressure (pressure in the eye) is controlled and the way cells transport fluid, and seeks to find methods to regulate the mechanisms involved. His goal is to develop drugs that reduce intraocular pressure, thereby decreasing the severity of glaucoma and damage to the retina. His cataract research also offers a promising model for tissue preservation, which will delay the onset of cataracts. https://delamerelab.medicine.arizona.edu/

Publications

Delamere, N., Pelis, R. M., Shahidullah, M., Ghosh, S., Coca-Prados, M., Wright, S. H., & Delamere, N. A. (2009). Localization of multidrug resistance-associated protein 2 in the nonpigmented ciliary epithelium of the eye. The Journal of pharmacology and experimental therapeutics, 329(2).

The nonpigmented epithelium (NPE) of the ciliary body represents an important component of the blood-aqueous barrier of the eye. Many therapeutic drugs penetrate poorly across the NPE into the aqueous humor of the eye interior. Several of these therapeutic drugs, such as methotrexate, vincristine, and etoposide, are substrates of the multidrug resistance-associated protein 2 (MRP2). Abundant MRP2 protein was detected by Western blot in homogenates of human ciliary body and freshly dissected porcine NPE. In cultured porcine NPE, the intracellular accumulation of the MRP2 substrates calcein (1.8-fold), 5-(and-6)-carboxy-2',7'-dichlorofluorescein (22.1-fold), and doxorubicin (1.9-fold) was significantly increased in the presence of 50 microM MK571 ((E)-3-[[[3-[2-(7-chloro-2-quinolinyl)-ethenyl]phenyl]-[[3-dimethylamino)-3-oxopropyl]thio]methyl]thio]-propanoic acid), an MRP inhibitor. In addition, the intracellular accumulation of the MRP2 substrate glutathione methylfluorescein was increased by 50 microM MK571 (4.3-fold), 500 microM indomethacin (2.6-fold), and 50 microM cyclosporin A (2.1-fold) but not by 500 microM sulfinpyrazone. These data are consistent with MRP2-mediated transport activity in cultured NPE, and MRP2 mRNA (reverse transcriptase-polymerase chain reaction) and protein (Western blot) were detected in the cultured cells. Immunolocalization studies in native human and porcine eyes showed MRP2 protein at the apical interface of the NPE and pigmented cell layers. Close examination of MRP2 immunoreactivity supported the conclusion that MRP2 is localized in the apical membrane of the NPE. MRP2 at the apical membrane of NPE cells may be involved in protecting intraocular tissues from exposure to potentially harmful toxins.