Associate Professor Biomedical Sciences Department 246 Padnos Hall Allendale, Michigan 49401 Phone: 616-331-8708 Fax: 616-331-2090 email: email@example.com OFFICE HOURS:
See available times here,
or by appointment
Research Associate, City University of New York, 2000 - 2004
Post-doctoral fellow, National Eye Institute, NIH, 1996 - 2000. Ph.D. Wayne State University School of Medicine, 1996 B.S. (Biology) Oakland University, Rochester, MI, 1985
Research in my lab examines the underlying biochemical and molecular processes that regulate the physiological state of a cell. In other words, we want to understand how a cell 'knows' what it is suppose to do and what triggers a cell to change its behavior. More specifically, we do vision research using the ocular lens as our scientific model. The lens is a remarkable tissue in that lens cells continually divide and differentiate throughout the entire life of an organism; yet every cell is retained, remaining tightly packed within the lens capsule.These ongoing processes are ideal for studying normal development and aging as well as pathological states such as cataract formation.
Our research is focused on the effects of transforming growth factor beta (TGF- ) on the terminal differentiation of chick lens cells. In culture, TGF- stimulates these cells to produce and deposit extracellular matrix proteins as well as to secrete and activate various matrix metalloproteinases, enzymes involved in the degradation and modification of matrix proteins. Therefore, in vivo, TGF- may be a major factor controlling lens cell migration along the capsule. Clinically, manipulation of TGF- concentrations within the eye could possibly inhibit the migration of lens cells; thus conceivably prevent secondary cataract formation following intra-ocular lens implantation. We use cultured chick lens cells treated with multiple concentrations of TGF- to examine the induction of gene expression of various extracellular proteins, metalloproteinases and integrins. We also want to investigate intercellular proteins involved in the TGF- signaling pathway. Techniques used in the lab include: tissue culture, protein and DNA isolation, PCR, enzyme activity assays, zymography, polyacrylamide gel electrophoresis and western blotting.
S.A. McClellan, X. Huang, R.P. Barrett, S. Lighvan, Y. Zhang, D.M. Richiert and L.D. Hazlett. Matrix metalloproteinase-9 amplifies the immune response to pseudomonas aeruginosa corneal infection. Invest Opthal. Vis. Sci. 47(1):256-64, 2006.
S.J. Tumminia, J.I. Clark, D.M. Richiert, K.P. Mitton, Y. Duglas-Tabor, J.A. Kowalak, D.L. Garland and P. Russell. Three distinct stages of lens opacification in transgenic mice expressing the HIV-1 protease. Exp. Eye Res. 72(2):115-121, 2001. T. Yamada, D.M. Richiert, S.J. Tumminia and P. Russell. The tensegrity model applied to the lens: a hypothesis for the presence of fiber cell ball and sockets. Med. Hypotheses 55(1):36-39, 2000. D.M. Richiert and M.E. Ireland. Matrix metalloproteinase secretion is stimulated by TGF- in cultured lens epithelial cells. Curr. Eye Res. 19(3):269-275, 1999. D.M. Richiert and M.E. Ireland. Transforming growth factor- elicits fibronectin secretion and proliferation in cultured chick lens epithelial cells. Curr. Eye Res. 18(1):62-71, 1999. M.E. Ireland, D.M. Richiert and K. Tran. Regulation of lens -adrenergic receptors by receptor occupancy and dexamethasone. J. Ocular Phar. 10(3):543-551, 1994. A.Banerjee, D.M. Richiert and M. Bagchi. Phosphorylation of small molecular weight polypetides in the iris-ciliary complex, aqueous humor and vitreous humor. Biochem. Biophys. Acta 1077(1):56-64, 1991. A.Banerjee, D.M. Richiert, K. Emanuel, A.K. Singh and M. Bagchi. Studies on the possible role of vitreous humor on the protein synthesis and morphology of the organ cultured adult rabbit lens. II. Epithelial cells. Biochem. Biophys. Acta 1076(3):330-336, 1991.