Professor, Department of Cell Biology,
George Lynn Cross Research Professor
Dean McGee Professor of Ophthalmology,
Adjunct Professor of Geriatric Medicine
B.A.., Mathematics, Texas A & M University, College Station, Texas
M.S., Biochemistry, Texas A & M University, College Station, Texas
Ph.D., Biochemistry, Texas A & M University, College Station, Texas
M.D., Baylor College of Medicine, Houston, Texas
American Association for the Advancement of Science
American Society for Cell Biology
American Society for Neurochemistry
Association for Research in Vision and Ophthalmology (ARVO)
FASEB (American Society for Biochemistry and Molecular Biology)
International Society for Eye Research
International Society for Neurochemistry
International Society for the Study of Fatty Acids and Lipids
Society for Neuroscience
We are studying signaling pathways and mechanisms in the retina and brain that provide neuroprotection from light (retina) and mutational stresses (retina and brain) that cause neurodegenerations. Several in vivo and in vitro approaches are used.
1). We made the unique observation that light activates the phosphoinositide signaling pathway through tyrosine phosphorylation of the insulin receptor, which leads to downstream activation of anti-apoptotic molecules, including Akt/PKB. It is our hypothesis that light capture by the rod and cone visual pigments routinely activates this pathway, which provides daily protection for these important post-mitotic neurons. Experiments are designed to elucidate the various steps that occur between photon capture and the stabilization of mitochondria/inhibition of caspases, which are necessary for neuroprotection. A variety of cell biological, biochemical, and molecular biological techniques are utilized in these studies, including the use of transgenic mice that express Cre recombinase in photoreceptor cells under the control of an inducible promoter. This approach has allowed us to knock out specific genes expressing proteins known to be involved in neuroprotection/apoptosis, only in specific cells such as rod and cone photoreceptors.
2). Stargardt-like macular dystrophy (STGD3) is a dominantly inherited juvenile macular degeneration that eventually leads to loss of vision. We have determined that the mutated gene in STGD3, identified by others as ELOVL4, encoded an enzyme responsible for biosynthesis of very long chain polyunsaturated (VLC-PUFA) and saturated (VLC-SFA) fatty acids (≥ 28 carbons) in the retina and a few select tissues (brain, skin, testes). Although we now know the function of the enzyme, it still remains to be determined why photoreceptor cells die in STGD3 patients. The answer to this question is important because it will determine therapeutic strategy. There are at least three explanations for the retinal phenotype seen in STGD3 patients: 1) VLC-PUFAs are necessary for cell survival and their loss leads to cell death, 2) Loss of ER retention signal leads to mislocalization of the ELOVL4 protein, which causes a metabolic stress that ultimately kills the cell, and 3) Mislocalization of the ELOVL4 leads to production of a intermediate (a 3-keto fatty acid) that is toxic to the cell. We are actively testing these three possible causes of cell death.
3). We have recently discovered that very long chain saturated fatty acids (VLC-SFA) synthesized in the brain by ELOVL4 are in sphingolipids and are enriched in synaptic vesicles. Deletion of the Elovl4 gene results in seizures at P19 and death by P21. Extracellular recordings of hippocampal slices using a 64-electrode array found increased spontaneous activity. FM dye uptake studies on primary cultures of hippocampal neurons showed faster fusion of vesicles in the Elovl4 deleted mice, consistent with the electrophysiology and seizure phenotype. Current studies are directed towards: 1) Determining if we can correct the seizure phenotype by providing pregnant dams VLC-SFA either in their diet or by transgenic expression of Elovl4 in their livers, 2) Mapping the distribution of ELOVL4-expressing neurons in the brain (collaboration with Dr. David Sherry), 3) Determining which genes may be up- or down-regulated in the Elovl4-deleted neurons by doing RNA-Seq analysis on P10 and P19 mutant, heterozygous, and wild type pups and in cultured neurons from E19 mice with and without VLC-SFA supplementation and with rescue with WT and mutant Elovl4 adenoviral constructs (RNA-Seq studies done in collaboration with Dr. Willard Freeman).
Notable discoveries from Dr. Anderson's laboratory include: 1) First demonstration of the essentiality of omega-3 fatty acids in retinal function, 2) The role of the phosphoinositide cascade in phototransduction in the invertebrate retina, 3) The role of the insulin receptor/PI 3-kinase/Akt pathway in stress-induced retinal degenerations, 4) The role of oxidant stress in light-induced apoptosis of photoreceptor cells, 5) The identification of the biosynthetic step catalyzed by the ELOVL4 protein, which is mutated in Stargardt-like macular dystrophy, 6) Discovery that phenyl-N-tert-butyl nitrones (PBN) protects the retina from stress-induced degeneration by inhibiting RPE65, a retinol ester isomerase in the retinalpigment epithelium, and 7) Discovery that VLC-SFA are essential for normal brain development and function.
The ultimate goal of our retinal research program is to elucidate the molecular mechanisms of retinal degenerations and to use this knowledge to provide medical therapy to patients that suffer from devastating blinding diseases such as age-related macular degeneration, retinitis pigmentosa, Usher Syndrome, and Stargardt Disease. The goal of our brain research program is to define the role of very long chain fatty acids in the synapse and to find ways of providing the missing fatty acids to patients with neurodegenerative diseases such as spinocerebellar ataxia.
Rajala A, Gupta, VK, Anderson RE, Rajala RVS. (2013). Insulin-phosphoinositide 3-kinase pathway regulates hexokinase-mitochondria interaction in the retina. Mitochondrion 13:566-576. [August 30, Epub ahead of print]. PMC3818532
Rajala A, Dighe R, Agbaga, M-P, Anderson RE, Rajala RVS. (2013). Insulin receptor signaling in cones. J Biol Chem, 288:19503-19515. May 14. [Epub ahead of print]. PMC3707652
Logan S, Agbaga M-P, Chan MD, Kabir N, Mandal NA, Brush RS, Anderson RE. (2013). Deciphering mutant ELOVL4 activity in autosomal dominant Stargardt Macular Dystrophy. Proc. Natl. Acad. Sci. USA, 110:5446-51. Mar 18. [Epub ahead of print]. PMC3619277
Garanto A, Mandal NA , Egido-Gabás M, Marfany G, Fabriàs G, Anderson RE, Casas J, Gonzàlez-Duarte, R. (2013) Specific sphingolipid content decrease in Cerkl knockdown mouse retinas. Exp. Eye Res. 110:96-106.
Logan S, Agbaga M-P, Chan MD, Brush RS, Anderson RE. (2014). ER microenvironment and conserved histidines govern ELOVL4 activity in VLC fatty acid elongation. J. Lipid Res. 55:698-708.
Bennett LD, Brush RS, Chen M, Lydic TA, Reese K, Reid GE, Busik JV, Elliott MH, Anderson RE (2014). Effect of reduced retinal VLC-PUFA on rod and cone photoreceptors. Invest Ophthalmol Vis Sci., 55:3150-3157. On line April 10.
Bennett LD, Hopiavuori BR, Brush RS, Chen M, Van Hook MJ, Thoreson WB, Anderson RE. (2014). Examination of VLC-PUFA-deficient photoreceptor terminals. Invest Ophthalmol Vis Sci. 55:3150-3157. On line April 24.
Mandal, NA, Tran J-TA, Zheng L, Wilkerson JL, Brush RS, McRae J, Agbaga M-P, Zhang K, Petrukhin K, Ayyagari R, Anderson RE (2014). In vivo effect of mutant ELOVL4 on the expression and function of wild type ELOVL4. Invest Ophthalmol Vis Sci. 55:2705-2713. On line March 18.
Agbaga M-P, Tam BM, Wong JS, Yang LL, Anderson RE, Moritz OL (2014). Mutant ELOVL4 that causes autosomal dominant Stargardt-3 macular dystrophy is misrouted to rod outer segment disks. Invest Ophthalmol Vis Sci. 55:3669-3680. On line May 15.
Rajala RVS, Rajala A, Morris AJ, Anderson RE (2014). Phosphoinositides: Minor lipids make a major impact on photoreceptor cell functions. Scientific Reports, On line June 26, 2014.
Rajala RV, Ranjo-Bishop M, Wang Y, Rajala A, Anderson RE. (2015). The p110α Isoform of Phosphoinositide 3-Kinase is Essential for Cone Photoreceptor Survival. Biochimie. 112:35-40. On line Mar 2. pii: S0300-9084(15)00053-X. doi: 10.1016/j.biochi.2015.02.018. [Epub ahead of print] PMC4402270
Stiles M, Moiseyev GP, Eckerd A, Brush RS, Budda ML, White GL, Wolf RF, Ma J-x, Floyd R, Anderson RE, Mandal NA (2015). PBN (phenyl-N-tert-butylnitrone)-derivatives are effective in slowing the visual cycle and rhodopsin regeneration and in protecting the retina from light-induced damage. PLoS One. 2015 Dec 22;10(12):e0145305. doi: 10.1371/journal.pone.0145305. eCollection 2015. PMID: 26694648 PMC4687940
Simón MV, Agnolazza DL, German OL, Garelli A, Politi LE, Agbaga M-P, Anderson RE, Rotstein NP (2016). Synthesis of docosahexaenoic acid from eicosapentaenoic acid in retina neurons protects photoreceptors from oxidative stress. J Neurochem. 136:931-946 PMID: 26662863
Dean A. McGee Eye Institute
608 Stanton L. Young, Blvd.
Oklahoma City, OK 73104
Phone: (405) 271-8250
Fax: (405) 271-8128 Robert-Anderson@ouhsc.edu