• Small GTPases in LTP, hippocampus-dependent learning and memory.
• Implication of small GTPases in defective synaptic plasticity.
• Rac1-dependent regulation of neuronal morphology in cognitive disabilities.

Our research is focused on elucidating the role of the small GTPase Rac 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.

A second aspect of our research is related to mental retardation (MR) syndromes. Precise synaptic connectivity is essential for normal brain function and the most common neuropathology associated with MR 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 in MR, 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 in MR 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 MR syndromes.

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.

Research Images

Students

Luis Alberto Martinez, B.S. (UH 2004)
Graduate Student (Pharmacology)
e-mail: lmartin306@gmail.com
Research: Therapeutic approaches in Autism

Stacy Nguy
Undergraduate Student, Biochemistry major
e-mail: n_stacy67@yahoo.com
Research: Small GTPase inhibitors and cognitive disorders

Tri Le
Undergraduate Student, Biology major with Chemistry and Health minors
e-mail: tle10@mail.uh.edu
Research: Statins and Autism

Nadeem Tajuddin, B.S. Medical Sciences      
University of Western Ontario
Summer 2008

Jermeece Augustine, B.S. Biology
University of Houston, Texas
May 2008 – May 2009

Mary Elhardt, B.S. Biology and Political Science
University of Houston, Texas
May 2008 – August 2010

Emmanuel Oni, B.S. Biology and Psychology
University of Houston, Texas
May 2009 – May 2010

Karlis Butler, B.S. Pharmaceutical Sciences
University of Houston, Texas
May 2009 – July 2010

Annie Pally, Undergraduate Student (Biochemistry/Honors College)
University of Houston, Texas
January 2011 – December 2011

Tina Nguyen, Undergraduate Student (Biochemistry)
University of Houston, Texas
January 2012 – May 2012

Odelia Bongmba, Ph.D. in Pharmacology (2012)
University of Houston, Texas
September 2007 – May 2012

Laboratory

Rodent Behavioral Room

May 2012    

Odelia Bongmba attended Novel Therapies in Neuroscience-International Conference on Neurology & Therapeutics-Neuro 2012 in Las Vegas, CA. She presented an oral talk entitled “Small GTP-binding proteins as a therapeutic target for cognitive deficiencies.”

July 2012

Dr. Tejada-Simon attended the 13th International Fragile X conference in Miami, FL. She presented the most recent work on “Exploring cholesterol dysfunction in a mouse model of Fragile X syndrome.”

August 2012

Dr. Tejada-Simon was awarded a renewal on her grant with the FRAXA Research foundation to continue her studies regarding novel targets and treatment for Fragile X syndrome.

September 2012

Luis Martinez received a FASEB-MARC award to attend next October the 2012 SACNAS National meeting that will be held in Seattle, WA.

Tri Le, undergraduate student in Biology, has joined the lab.

Stacy Nguy, undergraduate student in Biochemistry, has joined the lab.

October 2012

Professor Gunter P. Eckert, from the University of Frankfurt am Main in Frankfurt (Germany) visited the laboratory and the Department. He gave a seminar entitled “Enhanced brain isoprenoid levels: a novel common pathological hallmark of neurodegenerative diseases.”

Dr. Tejada-Simon presented “Exploring isoprenoids dysfunction in an animal model of autism” at the Society for Neuroscience annual meeting, in New Orleans, LA.

Dr. Tejada-Simon attended the first International Prenylation Society conference, held in New Orleans, LA, presenting her work on prenylated protein and their role in autism.

With an award from the FASEB-MARC program, Luis Martinez attended the SACNAS National meeting, in Seattle, WA. Luis Martinez presented his work in a poster entitled “Association of Rac1 dysregulation and learning disability.”

December 2012

Tri Le, undergraduate student in Biology, was awarded with the Spring 2013 Provost Undergraduate Research Scholarship (PURS), to conduct research exploring the role of statins in autistic disorders.

January 2013

Graduate student Luis Martinez received a FASEB-MARC award to attend 2013 Experimental Biology conference in April.

February 2013

Dr. Tejada-Simon received a FASEB-MARC faculty/student award to attend EB 2013.

March 2013

Dr. Tejada-Simon was awarded a renewal on her grant with the Jerome Lejeune foundation to continue her studies in Fragile X syndrome.

April 2013

Luis Martinez presented his work “Use of novel pharmacological agents to assess the role of Rho GTPase regulatory proteins in cognition” at Experimental Biology conference held in Boston, MA.

Dr. Tejada-Simon, and students Tri Le and Stacy Nguy attended the 2013 Experimental Biology Annual conference held in Boston, MA, sponsored by a Faculty-student award from FASEB-MARC.

Dr. Tejada-Simon received the inaugural 2013 Faculty Award for Mentoring Undergraduate Research (UH).

Dr. Tejada-Simon has been awarded a GEAR grant (Grants to Enhance and Advance Research) to study the “Therapeutic role of Statins in Autistic disorders.”

We are always looking for research graduate students, research technicians and post-doctoral fellows wishing to help unravel the causes for cognitive impairment, the signaling mechanisms involved and possible therapies to improve the quality of life of these patients. We use a combination of pharmacological, biochemical, electrophysiological and behavioral studies, coupled with the use of genetically altered mice.

Our research is mainly focused on providing important information regarding the signaling mechanisms that underlie synaptic plasticity, learning and memory processes. The consistent abnormality observed in brains of mental retardation subjects is an abnormal morphology of dendritic spines. These investigations might be translated to the basis of diseases involving memory impairment, such as Down syndrome, non-syndromic X-linked mental retardation (MRX), Fragile X mental retardation, Alzheimer’s disease, William’s syndrome, Angelman syndrome (AS), forebrain ischemia, and schizophrenia.

Please send a cover letter, CV, a brief statement of research interests, and contact information to: Dr. Tejada-Simon (mvtejada-simon@uh.edu).

• 2013 Faculty Award for Mentoring Undergraduate Research (UH)
• 2013 FASEB MARC Faculty-Student Award 
• 2012 Provost Faculty travel award
• 2010 Finalist, Sisley-Jerome LeJeune International Award
• 2010 FASEB-MARC Faculty-Student Award
• 2009 Carl Storm Scholarship, Gordon Research Conferences
• 2009 National Fragile X Foundation Travel Award
• 2008 Judge Funding Award, Annual Biomedical Research Conference for Minority Students (ABRCMS)
• 2008 Provost 2008-2009 Faculty Travel Award
• 2008 MEd Associates Scholarship award
• 2007 Academy Distinguished Educators Education Scholarship award (BCM)
• 2007 Biotechnology Institute Fellows Program Award. The Biotechnology Institute.
• 2006 Academy Distinguished Educators Education Award (BCM)
• 2005 Neuroscience Scholar Award (NINDS)
• 2004 National Institute of Neurological Disorders and Stroke (NINDS)
• 2001 Federation of Clinical Immunology Society Educational Award
• 2000 Methodist Hospital Foundation Grant Award, Methodist Hospital

Undergraduate courses

PCOL 3396, 4496 – Senior Research Project in Pharmacology

PCOL 3399, 4496 – Honors Thesis in Pharmacology

PharmD courses

PHAR 4400 – Cellular Life Science I

PHAR 5403 – Pharmacology II – CNS, psychosis and antipsychotics

Graduate courses

PCOL 7362 – Neuropharmacology

PCOL 6293, 6298, 6398 – Independent Studies in Pharmacology

PCOL 6370 – Advanced Pharmacology

PCOL 6498 – Special Problems in Pharmacology

PCOL 8300, 8699 – Doctoral Dissertation

• Society for Neuroscience (SFN)
• American Association of Colleges of Pharmacy (AACP)
• Soc. Advanc. Chicano & Native Americans in Science (SACNAS)
• American Society for Neurochemistry (ASN)
• American Physiology Society (APS)
• Molecular and Cellular Cognition Society (MCCS)
• National Hispanic Science Network (NHSN)
• International Prenylation Society (IPS)
• Biology of Behavior Institute (BoBI)