DIANNA A. JOHNSON, Ph.D.

Hiatt Professor

Department of Ophthalmology

Department of Anatomy and Neurobiology

The University of Tennessee College of Medicine

Address

The University of Tennessee Health Science Center

Hamilton Eye Institute

930 Madison Avenue, Suite 710

Memphis, TN 38163

Tel: (901) 448-1375; Fax: (901) 448-5028;

Education

Ph.D. Institution: University of Kansas, Lawrence, KSA

Postdoctoral: University of California, Irvine, CA

Research Interests

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.

Links

Ophthalmology - Dianna A. Johnson

Recent Publications

• Zhao T, Wang D, Cheranov SY, Karpurapu M, Chava KR, Kundumani-Sridharan V, Johnson DA, Penn JS, Rao GN. A novel role for activating transcription factor-2 in 15(S)-hydroxyeicosatetraenoic acid-induced angiogenesis. J Lipid Res. 2009 Mar;50(3):521-33. Epub 2008 Oct 10. PMID: 18849464
• Sharma RK, Netland PA, Kedrov MA, Johnson DA. Preconditioning protects the retinal pigment epithelium cells from oxidative stress-induced cell death. Acta Ophthalmol. 2009 Feb;87(1):82-8. Epub 2008 May 20. PMID: 18494742
• Bajpai AK, Blaskova E, Pakala SB, Zhao T, Glasgow WC, Penn JS, Johnson DA, Rao GN. 15(S)-HETE production in human retinal microvascular endothelial cells by hypoxia: Novel role for MEK1 in 15(S)-HETE induced angiogenesis. Invest Ophthalmol Vis Sci. 2007 Nov;48(11):4930-8. PMID: 17962441
• Ajioka I, Martins RA, Bayazitov IT, Donovan S, Johnson DA, Frase S, Cicero SA, Boyd K, Zakharenko SS, Dyer MA. Differentiated horizontal interneurons clonally expand to form metastatic retinoblastoma in mice. Cell. 2007 Oct 19;131(2):378-90. PMID: 17956737
• Johnson DA, Zhang J, Frase S, Wilson M, Rodriguez-Galindo C, Dyer MA. Neuronal differentiation and synaptogenesis in retinoblastoma. Cancer Res. 2007 Mar 15;67(6):2701-11. PMID: 17363591
• Johnson DA, Donovan SL, Dyer MA. Mosaic deletion of Rb arrests rod differentiation and stimulates ectopic synaptogenesis in the mouse retina. J Comp Neurol. 2006 Sep 1;498(1):112-28. PMID: 16856163

view complete list of references (pubmed link)