Masaru Miyagi, Ph.D.
Assistant Professor
Case Center for Proteomics
Department of Pharmacology
Department of Ophthalmology
Phone:(216) 368-5917
Fax: (216) 368-6846
E-mail:masaru.miyagi@case.edu
BRB 928
Research
My laboratory has two major research interests: 1) molecular mechanisms of retinal light damage and 2) development of proteomic methods.
Molecular Mechanisms of Light-induced Photoreceptor Cell Degeneration in Experimental Animals
Acute light-induced photoreceptor cell degeneration in experimental animals has been studied for more than 40 years as a model for visual cell loss arising from human retinal degenerative diseases such as age-related macular degeneration (AMD). The exact cause of AMD is unknown, but the photoreceptor cell degeneration, whether in AMD or a result of experimental light exposure, is generally characterized by apoptosis of photoreceptor cells. Oxidative stress has been indicated to be involved in the photoreceptor cell death in both AMD and the experimental model, because certain doses of antioxidants such as vitamin C appear to help control the advance of late AMD and to prevent the experimental light-induced damage. Therefore, elucidating the molecular mechanisms that trigger intense light-induced apoptosis might help to identify similar mechanisms in human diseases and lead to therapies that prevent AMD and other retinal degenerative diseases.We use proteomic and biochemical approaches to study molecular mechanisms of light-induced photoreceptor cell degeneration. It has been demonstrated that light-induced photoreceptor degeneration is circadian dependent; greater damage in rats exposed to light during the nighttime period than during the daytime period, suggesting that the expression profile of photoreceptor rod outer segments (ROS) proteins at the onset of light exposure appears to be important in determining light damage susceptibility. Therefore, we hypothesize that there are proteins expressed in ROS during the daytime period that protect photoreceptor cells from light damage. Our research effort has been focused on identifying such protective proteins against light damage.
Development of Proteomic Methods
The completion of the genome sequencing of humans and other species and the emergence of new technologies in mass spectrometry have together fostered unprecedented opportunities for studying proteins on a large scale. Although mass spectrometry is the pre-eminent technology in proteomics studies, currently available methods on the front end of the mass spectrometer are not satisfied for the maximum use of mass spectrometry technology. Therefore, development of new proteomics methods on the front end of the mass spectrometer is of critical importance towards the advancement of proteomics studies.
We are currently developing two proteomics methods. One is a proteolytic 18O labeling method for quantitative proteomics and the other is a method for selectively enriching nitrotyrosine containing peptides for determining the sites of nitration.
Selected References:
Hajkova, D., K. C. Rao, K. C. S., Miyagi, M. (2006) The pH dependency of the carboxyl oxygen exchange reaction catalyzed by lysyl endopeptidase and trypsin. J. Proteome Res. (In press)
Rao, K. C. S., Palamalai, V, Dunlevy, J. R. and Miyagi, M. (2005) Peptidyl-Lys Metalloendopeptidase Catalyzed 18O Labeling for Comparative Proteomics: Application to Cytokines/LPS Treated Human Retinal Pigment Epithelium Cell Line. Mol. Cell. Proteomics, 4, 1550-1557
Rao, K. C. S., Carruth R. T., Miyagi, M. (2005) Proteolytic 18O labeling by peptidyl-Lys metalloendopeptidase for comparative proteomics. J. Proteome Res. 4, 507-514
Qiu, Y., Ogawa, H., Miyagi, M., Misono, K. S. (2004) Constitutive activation and uncoupling of the atrial natriuretic peptide receptor by mutations at the dimer interface: Role of the dimer structure in signaling. J. Biol. Chem., 279, 6115-6123
Sakaguchi, H., Miyagi, M., Darrow, R. M., Crabb, J. S., Hollyfield J. G., Organisciak, D. T., and Crabb, J. W. (2003) Intense light exposure changes the crystalline content in Retina. Exp. Eye. Res., 76, 131-133
Crabb, J. W., Miyagi, M., Gu, X, Shadrach, K. G., West, K. A., Sakaguchi, H., Kamei, M., Hasan, A., Yan, L., Rayborn, M. E., Salomon, R. G., and Hollyfield, J. G. (2002) Drusen Proteome analysis as an approach to the etiology of age related macular degeneration. Proc. Natl. Acad. Sci. USA, 99, 14682-14687
Miyagi, M., Sakaguchi, H., Darrow, R. M., Yan, L., West, K. A., Aulak, K. S., Stuehr, D. J., Hollyfield J. G., Organisciak, D. T., and Crabb, J. W. (2002) Evidence that light modulates protein nitration in rat retina. Mol. Cell. Proteomics, 1, 293-303
Aulak, K. S., Miyagi, M., Yan, L., West, K. A., Massillon, D., Crabb, J. W., and Stuehr, D. J. (2001) Proteomic method to identify proteins nitrated in vivo during inflammatory challenge. Proc. Natl. Acad. Sci. USA, 98, 12056-12061
Miyagi, M., Zhang, X., and Misono, K. S. (2000) Glycosylation sites in the atrial natriuretic peptide receptor: Oligosaccharide structures are not required for hormone binding. Eur. J. Biochem., 267, 5758-5768
van den Akker, F, Zhang X., Miyagi, M., Huo, X., Misono, K S., and Yee, V. C. (2000) Structure of the dimerized hormone-binding domain of a guanylyl- cyclase-coupled receptor. Nature, 406, 101 – 104
Miyagi, M. and Misono, K. S., (2000) Disulfide bond structure of the atrial natriuretic peptide receptor extracellular domain: Conserved disulfide bond among guanylate cyclase-coupled receptors. Biochim. Biophys. Acta, 1478, 30-38
Pudota, B. N., Miyagi, M., Kevin, H., West, K. A., Crabb, J. W., Misono, K. S., and Berkner, K. L. (2000) Identification of the vitamin K dependent carboxylase active site: Cys99 and Cys450 bind glutamyl residues to properly orient vitamin K and initiate catalysis., Proc. Natl. Acad. Sci. USA, 97, 13033-13038