Translational and Clinical Neuroscience

Research Description

The goal of my basic science research is to understand the mechanisms by which genetic ion channel variants identified in patients with early-onset epilepsy translate to altered channel biophysics when isolated in an expression system, to abnormal intrinsic neuronal excitability when studied in patient-derived neurons (made from induced pluripotent stem cell lines), and to circuit-level disruption resulting in epileptogenesis in transgenic animal models. This three-pronged approach shares a common pathophysiologic protein, and is intended to identify new therapeutic targets by complementary ion channel, neuronal, and synaptic modulation.

For more information please view the faculty profile of Tracy Gertler, MD, PhD.

Publications

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Research Description

Publications

Contact

Research Description

Research in my laboratory centers on the molecular and cellular mechanisms that control the formation and modification of dendritic spines in the mammalian brain. These mechanisms underlie the normal development and plasticity of the brain, and contribute to higher brain functions, including cognitive, social, and communication behavior. However, when these mechanisms go awry, they lead to mental and neurological disorders. Our analysis integrates multiple organizational levels, from molecular, cellular, circuit, and rodent models, to human subjects. We employ both a “translational” strategy, utilizing basic mechanistic data we generate to understand disease pathogenesis, and a “reverse-translational” strategy, in which genetic, neuropathological, and imaging studies in human subjects help guide the discovery of novel mechanistic insight. The ultimate goal of these studies is to develop therapeutic approaches to prevent or reverse neuropsychiatric disorders, by targeting mechanisms that control dendritic spines and synapses.

• Mechanistic studies on the molecular mechanisms of dendritic spine plasticity: This line of research aims to identify and elucidate functions of novel molecular regulators of synaptic circuit modification during the lifespan. We investigate the formation, remodeling, and elimination of spiny synapses in neurons using both in vitro and in vivo models. We are particularly interested in signaling, adhesion, and scaffolding molecules that control cell-to-cell communication and mediate intracellular signaling by neurotransmitter receptors. My laboratory continues to investigate small GTPase pathways and the roles of guanine-nucleotide exchange factors, such as kalirin and Epac2, and their downstream targets Rac, PAK, Rap and Ras. In addition, we have made important contributions to understanding how synaptic activity controls synapse size and strength through a pathway involving NMDA receptors, CaMKII, kalirin, Rac1 and actin, how rapid synaptic plasticity in the brain is regulated by locally synthesized estrogen, how adhesion molecules including N-cadherin control synapse size and strength, and how dopamine and neuroligin control synapse stability though Epac2 and Rap1.
• Translational and reverse-translational studies on the molecular substrates of dendritic spine pathology: Investigations of genetic, neuropathological, and neuromorphological alterations in human subjects with psychiatric disorders have started to reveal the pathogenic mechanisms behind these illnesses, and are also guiding the discovery of unexpected basic mechanisms of brain development and function. Through studies performed in the lab and through collaborations, we investigate molecular and cellular alterations occurring in patients with schizophrenia, bipolar disorder, autism, and Alzheimer’s disease. We then use model systems, such as neuronal cultures or mice, to elucidate the functions and pathogenic mechanisms of key molecules. We are currently investigating the basic synaptic functions of several leading mental disorder risk genes, to understand how they contribute to normal brain function and to synapse pathology. Conversely, many molecules we have been studying in the lab have more recently been implicated in the pathogenesis of mental disorders through independent neuropathological or genetic studies. We have shown that molecules that control basic synapse structural plasticity, such as kalirin and Epac2, functionally interact with leading mental disorder risk molecules, such as neuregulin1, ErbB4, DISC1, 5HT2A receptors, dopamine receptors, neuroligin, and Shank3. We have generated mutant mice in which kalirin or Epac2 are ablated, and have shown that these molecules control behaviors relevant for mental disorders, such as sociability, working memory, sensory motor gating, and vocalizations. These animal models can thus help to understand the synaptic substrates of specific aspects of mental disorders. To investigate the abnormal regulation of these molecular pathways in schizophrenia, autism, Alzheimer’s disease, and the impact of these molecular abnormalities on disease phenotypes in human subjects, we are collaborating with neuropathologists, brain imaging experts, and geneticists who investigate human subjects.

Therapeutic reversal of neuropsychiatric disease by targeting synaptic connectivity. By harnessing the knowledge from our basic and reverse-translational studies, my goal is to develop novel therapeutic approaches to prevent, delay, or reverse the course of mental and neurodegenerative disorders. Because abnormal synaptic connections play central roles in the pathogenesis of schizophrenia, autism, and Alzheimer’s disease, pharmacological targeting of key molecules implicated in synaptic plasticity and pathology can rescue disease associated abnormalities, and thereby influence the outcome of the disease. We are currently developing transgenic animal models to validate synaptic signaling molecules as therapeutic targets in mental disorders. We are also developing cellular assays which we will use in high-throughput screens for small-molecule regulators of synapse remodeling. Our goal is to identify small-molecule regulators of synapse remodeling which can be taken into clinical trials as therapeutics aimed at reversing synaptic deficits, and thus cognitive dysfunction, in mental disorders.

In our studies, we employ a multidisciplinary approach, using an array of methods that include advanced cellular and in vivo microscopy, biochemistry, electrophysiology, manipulations of gene expression in vivo, mouse behavioral analysis, circuit mapping, and human genetics and neuropathology.

For lab information and more, see Dr. Penzes' faculty profile.

Publications

See Dr. Penzes' publications on PubMed.

Contact

Contact Dr. Penzes at 312-503-5379.

Research Faculty: Marc Forrest, Euan Parnell, Sehyoun Yoon, Colleen Zaccard

Postdoctoral Fellows: Nicolas Piguel, Marc Dos Santos

Technical Staff: Jessica Christiansen Blair Eckman