Dianna A. Johnson, Ph.D.
Department of Ophthalmology
Department of Anatomy and Neurobiology
The University of Tennessee Health Science Center
Hamilton Eye Institute
930 Madison Avenue, Suite 710
Memphis, TN 38163
Phone: (901) 448-1375
Fax: (901) 448-5028
Email: Dianna A. Johnson
- Ph.D. Institution: University of Kansas, Lawrence, KSA
University of California, Irvine, CA
This laboratory focuses on studies of neurotransmitters in the retina and their general actions as molecular signals in the transmission of visual information. In addition, there is particular interest in what might be considered as special functions of transmitters, namely their role as developmental signals during early states of retina maturation and as signaling factors involved in certain retinal disease states. Based on their findings, it appears that GABA and glutamate are necessary for normal development of cone photoreceptor synaptic circuits in the outer plexiform layer in rabbit retina. Ongoing studies are examining the signaling transduction cascade involved in these developmental interactions.
Excitotoxic actions of glutamate have been well documented in virtually all types of nervous tissue including retina. It has been suggested that the loss of retinal neurons resulting from a variety of causes including ischemia, laser exposure, glaucoma and developmentally programmed cell death, may all involve a common pathway triggered by abnormal release of glutamate. In experiments utilizing both rabbit and human retinas, they are examining this hypothesis in order to determine the intra-cellular mechanisms involved and to test the efficacy of pharmacological agents in protecting against glutamate-induced cell death.
- Bhattacharya S, Chaum E, Johnson DA, Johnson LR. Age-related susceptibility to apoptosis in human retinal pigment epithelial cells is triggered by disruption of p53-Mdm2 association. Invest Ophthalmol Vis Sci. 2012 Dec 19;53(13):8350-66. doi: 10.1167/iovs.12-10495. PubMed PMID: 23139272.
- Steinle JJ, Zhang Q, Thompson KE, Toutounchian J, Yates CR, Soderland C, Wang F, Stewart CF, Haik BG, Williams JS, Jackson JS, Mandrell TD, Johnson D, Wilson MW. Intra-ophthalmic artery chemotherapy triggers vascular toxicity through endothelial cell inflammation and leukostasis. Invest Ophthalmol Vis Sci. 2012 Apr 30;53(4):2439-45. doi: 10.1167/iovs.12-9466. PubMed PMID: 22427570.
- Martins RA, Davis D, Kerekes R, Zhang J, Bayazitov IT, Hiler D, Karakaya M, Frase S, Gleason S, Zakharenko SS, Johnson DA, Dyer MA. Retinoblastoma (Rb) regulates laminar dendritic arbor reorganization in retinal horizontal neurons. Proc Natl Acad Sci U S A. 2011 Dec 27;108(52):21111-6. doi: 10.1073/pnas.1108141108. Epub 2011 Dec 12. PubMed PMID: 22160703; PubMed Central PMCID: PMC3248513.
- McEvoy J, Flores-Otero J, Zhang J, Nemeth K, Brennan R, Bradley C, Krafcik F, Rodriguez-Galindo C, Wilson M, Xiong S, Lozano G, Sage J, Fu L, Louhibi L, Trimarchi J, Pani A, Smeyne R, Johnson D, Dyer MA. Coexpression of normally incompatible developmental pathways in retinoblastoma genesis. Cancer Cell. 2011 Aug 16;20(2):260-75. doi: 10.1016/j.ccr.2011.07.005. PubMed PMID: 21840489; PubMed Central PMCID: PMC3551581.
- Bhattacharya S, Ray RM, Chaum E, Johnson DA, Johnson LR. Inhibition of Mdm2 sensitizes human retinal pigment epithelial cells to apoptosis. Invest Ophthalmol Vis Sci. 2011 May 1;52(6):3368-80. doi: 10.1167/iovs.10-6991. PubMed PMID: 21345989; PubMed Central PMCID: PMC3109032.
- Zhang Q, Wang D, Kundumani-Sridharan V, Gadiparthi L, Johnson DA, Tigyi GJ, Rao GN. PLD1-dependent PKCgamma activation downstream to Src is essential for the development of pathologic retinal neovascularization. Blood. 2010 Aug 26;116(8):1377-85. doi: 10.1182/blood-2010-02-271478. Epub 2010 Apr 26. PubMed PMID: 20421451; PubMed Central PMCID: PMC2938243.