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Faculty Profile

Maria Victoria Tejada-SimonMaria Victoria Tejada-Simon

Assistant Professor of Pharmacology
Pharmacological and Pharmaceutical Sciences Department

Office: SR2 551
Contact: mvtejada@mail.uh.edu - (713) 743-7835

Education: Ph.D., Michigan State University, Lansing


Learning and memory

Our research is focused on elucidating the role of the small GTPases in LTP and in hippocampus-dependent learning and memory. In area CA1 of the hippocampus, the most commonly studied form of LTP is dependent on the activation of NMDA receptors. Previously in our laboratory we have found that Rac is highly expressed in the adult mouse hippocampus where it is equally distributed between cytosolic and membrane fractions, indicating that this protein might be cycling between inactive and active forms. In addition, our investigation showed that NMDA receptor activation in hippocampal slices causes Rac to translocate to the membrane in a manner similar to that observed in activated phagocytic cells, and that translocation and activation of Rac occurs during associative contextual fear learning in the hippocampus of the adult animal. We are currently investigating whether Rac is an important molecule involved post-developmentally in synaptic plasticity in the adult mice, playing a role in the neuro-anatomical and cyto-architectural changes of neurons and in the activation of signal transduction pathways associated with LTP and hippocampal learning and memory.

Defective neuronal plasticity in diseases with cognitive impairment

A second aspect of our research is the study of diseases with cognitive impairment, such as mental retardation (MR) syndromes, autistic disorders and schizophrenia. Precise synaptic connectivity is essential for normal brain function and the most common neuropathology associated with this type of syndromes is an alteration of this connectivity due to aberrant dendritic spine morphology. Abnormalities in dendrites and spines have been associated with the impaired cognitive abilities, but how they were generated is not yet well understood. It is of great interest to understand the mechanism that lead to lose of synapses and defective synaptic plasticity. In this regard, there is evidence pointing to the Rho family of small GTPases, proteins that mediate actin cytoskeleton reorganization, neuronal morphogenesis and gene expression. The role of the small GTPases-linked genes could provide a connection between the mechanism and the neuronal microstructural deficits observed in these cognitive disorders. Thus, our laboratory is investigating Rac-dependent regulation of neuronal morphology in syndromes presenting impaired cognition.

For all these studies we use a multidisciplinary approach, a combination of pharmacological, biochemical, electrophysiological and behavioral studies, coupled with the use of genetically altered mice.

  • Elhardt, M.E.; Martinez, L.A.; Tejada-Simon, M.V. (2009). Parallels among molecular, behavioral and architectural effects in the schizophrenia mouse model of NMDA receptor hypofunction. (in review).
  • LeBaron, R.G.; Asher, A.M.; Medina, D.A.; Navarro, M.M.; Tejada-Simon, M.V. (2008). Extracellular ligands involved in learning and memory. Matrix Biology, 27:46.
  • Hoeffer, C.A., Tang, W., Wong, H., Santillan, A., Patterson, R.J., Martinez, L.A., Tejada-Simon, M.V., Paylor, R., Hamilton, S.L., and Klann, E. (2008). Removal of FKBP12 enhances mTOR/Raptor interactions, LTP, memory, and perseverative/repetitive behavior. Neuron, 60(5):832-845.
  • Martinez, L.A.; Klann, E.; Tejada-Simon, M.V. (2007). Translocation and activation of Rac in the hippocampus during associative contextual fear learning. Neurobiol. Lear. Mem., 88:104-113.
  • Tejada-Simon, M.V. (2007). Bringing together the main players on synaptic potentiation. Cell Science, 4(1):37-42.
  • Tejada-Simon, M.V.; Villasana, L.E.; Serrano, F.; Klann, E. (2006). NMDA receptor activation induces membrane translocation and activation of Rac in mouse hippocampal area CA1 . Biochem. Biophys. Res. Comm., 343(2):504-512.
  • Villasana, L.E.; Klann, E.; Tejada-Simon, M.V. (2006). Rapid isolation of synaptoneurosomes and postsynaptic densities from adult mouse hippocampus. J. Neurosci. Met., 158:30-36.
  • Tejada-Simon, M.V.; Serrano, F.; Villasana, L.E.; Kanterewicz, B.; Wu, G-Y.; Quinn, M.; Klann, E. (2005). Synaptic localization of a functional NADPH oxidase in the mouse hippocampus. Mol. Cell. Neurosci., 59:97-106.
  • Tejada-Simon, M.V.; Zang, Y.C.; Hong, J.; Rivera, V.M.; Zhang, J.Z. (2003). Cross-reactivity with myelin basic protein and human herpesvirus-6 in multiple sclerosis. Ann.Neurol., 53(2):189-197.
  • Klann, E.; Serrano, F.; Tejada-Simon, M.V.; Villasana, L.E.; Kishida, K.T. (2003) Reactive oxygen species: cellular signaling molecules critical for hippocampal LTP and memory. J. Neurochem., 87:21.
  • Klann, E.; Tejada-Simon, M.V.; Serrano, F.; Villasana, L.E.; Kishida, K.T. (2003) Redox signaling in hippocampal LTP and memory formation. J. Physiol., 551P, SA5.
  • Hong, J., Tejada-Simon, M.V., Rivera, V.M., Zang, Y.C. and Zhang, J.Z. (2002) Anti-viral properties of interferon beta treatment in patients with multiple sclerosis. Mult. Scler., 8(3):237-242.
  • Tejada-Simon, M.V.; Zang, Y.C..; Hong, J.; Rivera, V.M.; Killian, J.M.; Zhang, J.Z. (2002). Detection of viral DNA and Immune responses to the Human Herpesvirus-6 101-Kilodalton virion protein in patients with Multiple Sclerosis and in controls. J. Virol., 76(12):6147-6154.
  • Zhang, J.Z.; Rivera, V.M.; Tejada-Simon, M.V.; Yang, D.Y.; Hong, J.; Li, S.F.; Haykal, H.; Killian, J.; Zang, Y.C.Q. (2002). T cell vaccination in multiple sclerosis: Results of a preliminary study. J. Neurol., 249 (2): 212-218.
  • Godkin, A.J.; Smith, K.J.; Willis, A.; Tejada-Simon, M.V.; Zhang, J.; Elliott, T.; Hill, A.V.S. (2001). Naturally processed HLA class II peptides reveal highly conserved immunogenic flanking region sequence preferences that reflect antigen processing rather than peptide-MHC interactions. J. Immunol., 166:6720-6727.
  • Tejada-Simon, M.V.; Hong, J. and Zhang, J.Z. (2001). Autoimmune responses to myelin oligodendrocyte glycoprotein in Multiple Sclerosis. Clin. Immunol., 99(1):138.
  • Tejada-Simon, M.V.; Hong, J.; Zang, Y.C.Q. and Zhang, J.Z. (2001). Association of human herpesvirus-6 and Multiple Sclerosis. Clin. Immunol., 99(1):158.
  • Tejada-Simon, M.V.; Hong, J.; Rivera, V.M.; Zhang, J. (2001). Reactivity pattern and cytokine profile of T cells primed by myelin peptides in Multiple Sclerosis and healthy individuals. Eur. J. Immunol., 31(3):907-917.
  • Tejada-Simon, M.V.; Hong, J.; Rivera, V.M.; Zhang, J.Z. (2002). Skewed autoantibody reactivity to the extracellular domain of Myelin Oligodendrocyte Glycoprotein in Multiple Sclerosis. Immunol., 107(4): 403-410.
  • Tejada-Simon, M.V.; Zang, Y.C.Q.; Hong, J.; Li, S.; and Zhang, J.Z. (2000). Aberrant T cell responses to myelin antigens during exacerbation in patients with Multiple Sclerosis. FASEB J., 14(6):A1106, sup.
  • Tejada-Simon, M.V.; Zang, Y.C.Q.; Yang, D.; Hong, J.; Li, S.; Singh, R.A.K.; Killian, J.M.; Rivera, V.M.; Zhang, J. (2000). Aberrant T cells responses to myelin antigens during exacerbation in patients with Multiple Sclerosis. Int. Immunol., 12:1629-1639.