ASPET Researchers
This ASPET Institutional Summer Undergraduate Research Fellowship (SURF) Program provides hands-on summer research experiences to undergraduate students.
The scientific research focus of this SURF program is Neuropharmacology.
Research will be conducted under the mentorship of faculty in the Department of Biomedical Sciences at the University of North Dakota School of Medicine & Health Sciences in Grand Forks, ND. Mentors, all of whom are members of ASPET will work closely with students to develop an independent research project. Some possible research projects involve adrenergic regulation of neurogenesis & cognitive function; dopamine transporter (DAT) pharmacology & regulation; DAT & serotonin transporter structure function; epigenomic modification; neuroimmunology.
These research projects are relevant to a number of neurological disorders including Addiction, Alzheimer’s disease, Anxiety, Depression, Epilepsy, Parkinson’s disease, and Schizophrenia.
ASPET faculty mentors include:
Colin K. Combs, Ph.D.
Project: Novel Strategies for Attenuating the Inflammatory Contribution to Alzheimer’s Disease
Mentor: Colin K. Combs, Ph.D.
Professor and Chair, Department of Biomedical Sciences
Research Aims: This project’s goal is to determine the mechanisms by which immune cells in the periphery
interact with brain resident immune cells to influence brain function during aging
and Alzheimer’s disease (AD). Population and single cell transcriptomic analysis of
brain resident immune cells, microglia, clearly demonstrate that these cells change
their phenotype during AD. Moreover, numerous epidemiological and GWAS studies support
a critical role for inflammatory changes during disease. Although some of these changes
are related to the microenvironment of the brain, the influence of peripheral immune
cell behavior on the phenotype of microglia has become increasingly understood during
disease. Our prior work has shown that selectively manipulating peripheral immune
cell behavior with immunomodulatory strategies is sufficient to provide protective
changes in microglial phenotype. Using a transgenic mouse model of Alzheimer’s disease,
this project seeks to better define molecular signals influencing the inflammatory
changes that regulate disease progression. Specific pharmacologic interventions using
non brain-penetrant biologic and small molecule approaches will be tested for their
ability to attenuate the peripheral to brain communication of inflammatory changes.
Techniques: Students will learn rodent husbandry, genotyping and drug delivery via intravenous/intraperitoneal injection and oral gavage. In addition, they will become familiar with PK/PD related testing. Finally, students will learn assays, ELISA, flow cytometry, immunohistochemistry, mass spectrometry, and microscopic techniques relevant to brain along with statistical analysis, hypothesis testing, and scientific writing skills.
Student Independence: The SURF student will work with Dr. Combs to design a particular drug delivery paradigm to administer novel immunomodulatory therapeutics to control AD mice. The student will also be responsible for literature review and suggestion of possible delivery paradigm and animal collection. Once the student has been trained on the staff and passes an in-lab certification for the particular delivery paradigm, he/she will be responsible for scheduling and delivering drugs to final brain and blood collections. The student will be expected to help plan the particular series of analyses from the collected tissue and present findings at weekly lab meetings. At all times, the student will have access to Dr. Combs, lab manager, multiple post-docs, graduate students, and additional undergraduate students for any assistance that is needed.
Van A. Doze, Ph.D.
Project: Noradrenergic Regulation of Neurogenesis and Cognitive Function
Mentor: Van A. Doze, Ph.D.
Associate Professor, Department of Biomedical Sciences
Research Project: Norepinephrine (NE), an important neuromodulator in the brain, modulates cognitive
function and synaptic plasticity. NE mediates its effects via activation of adrenergic
receptors (ARs). We discovered that adult mice with chronically activated alpha1A-ARs
exhibit significantly improved learning and memory, synaptic transmission, mood, and
lifespan. In contrast, we found that mice lacking alpha1A-ARs have reduced cognitive
function, mood, and lifespan. The mice with activated alpha1A-ARs also show increased
neurogenesis in their hippocampus, an area of the brain critical for learning and
memory. The molecular cues and genes regulating this process include a wide range
of growth and survival factors, but a direct link between NE activity, gene regulation,
and neurogenesis has not been explored. This project will test the hypothesis that
NE, through alpha1A-AR activation regulates differentiation and cell fate of neuronal
and glial progenitors in the adult mouse brain, and subsequently enhances cognitive
function. This project will characterize alpha1A-AR influences on adult mammalian
neurogenesis and learning and memory. These results may have important implications
for the treatment of certain neurodegenerative disorders such as Alzheimer’s disease
and epilepsy.
Techniques: The SURF student will learn immunolabeling, stereology, behavioral studies, electrophysiology, transgenic methodology, imaging, as well as pharmacological principles, statistical analysis, and hypothesis testing. The student will also be exposed to literature on adrenergic pharmacology, adult neurogenesis, transgenic, and Alzheimer’s disease, as well as research findings in posters and papers.
Student Independence: The SURF student will have independence to do experiments daily, with assistance as needed, and to analyze results for discussion with Dr. Doze. The student will be able to suggest experimental directions as dictated by findings and formulate new ideas.
James D. Foster, Ph.D.
Project: Regulation of Membrane Transporters by Palmitoylation
Mentor: James D. Foster, Ph.D.
Assistant Professor, Department of Biomedical Sciences
Research Project: The dopamine transporter (DAT) and serotonin transporter (SERT) are membrane proteins
responsible for clearance of corresponding substrates (dopamine and serotonin) from
the extracellular space during neurotransmission. Each monoamine controls distinct
behavioral and physiological functions in the nervous system. Extraneuronal monoamine
levels are controlled spatially and temporally by transporter mediated reuptake of
released transmitter into presynaptic neurons. Abnormalities in transmitter levels
and subsequent neurotransmission are linked to neurological disorders including major
depression, schizophrenia, bipolar disorder, attention deficit hyperactivity disorder,
Tourette syndrome, and Parkinson disease, through mechanisms that are incompletely
understood. In addition, the transporters are sites of action for therapeutic drugs
such as methylphenidate, bupropion, selective serotonin and norepinephrine reuptake
inhibitors, used to treat these disorders, and are also targets for addictive drugs
including cocaine, amphetamine, methamphetamine, and MDMA (ecstasy). We previously
discovered that rat, mouse and human DATs are modified by S-palmitoylation, a post-translational
modification in which C16 saturated palmitic acid is added via a thioester linkage
to cysteine. Our studies indicate that DAT palmitoylation has the capacity to impact
dopamine signaling acutely by regulating DA transport kinetics independent of surface
losses and chronically by opposing DAT degradation. We have also identified NET, SERT
and the sodium hydrogen ion exchanger 1 (NHE1) as palmitoylated transporters but the
sites of modification remain unknown. We have begun to identify the signaling pathways
regulating palmitoylation of these functional outcomes and their proposed project
for the SURF student will be to characterize transporter palmitoylation in response
to one of the following drugs of abuse (AMPH, MDMA, etc.), growth factors (insulin,
BDNF, etc.) or specific signaling pathway inhibitors, and resulting effects on transport
capacity and cell surface transporter expression as time permits.
Techniques: The SURF student will learn culture and transfection of cells, basic biochemistry, and cell biology techniques related to palmitoylation, including acyl-biotin exchange, Western Blotting, and radioligand binding. The student will also be exposed to pharmacological principles, cell culture and transfection, statistical analysis, and hypothesis testing. The student will also be given exposure to transporter literature, and the opportunity to write up research findings for posters or papers.
Student Independence: The SURF student will perform daily experiments, with guidance as needed, and will analyze results for discussion with Dr. Foster. Initially, it is expected that more assistance will be needed while the student gains more independence. In the latter weeks of the experience, the student will have significant input into the interpretation of results and planning of further experiments.
Keith Henry, Ph.D.
Project: Substrate and Antagonist Molecular Determinants in the Dopamine and Serotonin Transporters
Mentor: L. Keith Henry, Ph.D.
Associate Professor, Department of Biomedical Sciences
Research Project: The project will focus on identification and characterization of molecular determinants
that discriminate substrates from antagonists in the serotonin and dopamine transporters.
We have identified that substrate selectivity for neurotransmitters and drugs of abuse
such as MDMA (ecstasy) occur through divergent interactions. Understanding these key
differences could lead to unique pharmacological approaches to selectively block the
actions of drugs of abuse. This project is ideal for an undergraduate and will focus
on generating site-directed mutants in amino acids attributed to outer gate function
as well as the phosphorylation sites located on the N-terminus. The functional readouts
will include expression and transport levels using radiolabeled and fluorescent transport
assays along with Western Blot techniques.
Techniques: The SURF student will learn basic and advanced principles of pharmacology and small molecule interactions with targets using biochemical and computational approaches. These will include (but not limited to) transport assays, binding assays, Western Blots, chemical crosslinking, molecular mutagenesis and cloning, and affinity purification.
Student Independence: The SURF student will be given a project that is independent of other students but will be provided guidance and mentorship appropriate for their experience and background with the understanding they are expected to move toward independence on their project. Dr. Henry will oversee this process and assess regularly via questions and monitoring.
Roxanne A. Vaughan, Ph.D.
Project: Dopamine Transporter Regulation
Mentor: Roxanne A. Vaughan, Ph.D.
Professor, Department of Biomedical Sciences
Research Project: The dopamine transporter, DAT, is a synaptic protein that drives reuptake of dopamine
from the synapse into the presynaptic neuron, and is the major mechanism for regulation
of DA neurotransmission. DAT activity is regulated by phosphorylation of multiple
serine and threonine residues, driven by multiple protein kinases, but many major
questions remain as to the mechanisms underlying the responses. Regulatory mechanisms
linked to phosphorylation are induced not only by exogenous activators of Protein
Kinase C (PKC), but also by amphetamine and methamphetamine, indicating the involvement
of these abused drugs in endogenous regulatory mechanisms. More recently we have extended
our studies to regulation processes of the synthetic cathinones mephedrone (MCAT)
and methylenedioxypyrovalerone (MDPV). These psychoactive and addictive compounds
are of major concern in the drug abuse community, but their mechanisms of action are
currently poorly understood.
**Preliminary work in our lab has shown that pretreatment of DAT-expressing cells with MCAT and MDPV induce DAT regulatory responses and affect phosphorylation of DAT residue Threonine (T53). We have generated a phospho-specific antibody against T53 for analysis of this site, and our proposed project for the SURF student will be to characterize this phosphorylation process for dose and time courses of responses to MCAT and MDPV, using previously characterized amphetamine or PKC as controls. As time permits, the student will determine levels of DAT and transport activity in parallel conditions and assess DAT regulatory responses in a phosphorylation-null T53A mutant. The results will indicate if MCAT and MDPV exert physiological dysfunction in DAT as part of their overall actions.
Techniques: The project is suitable for execution by an undergraduate student in that the constructs and assay conditions have been worked out, and the questions to be answered are scientifically important. The study will introduce the student to many pharmacological principles related to DAT and drug abuse, as well as basic scientific principles in experimental methodology, including radiolabeling, Western Blotting, cell culture, transfection, statistical analysis, and hypothesis testing. The student will also be given exposure to DAT literature, and the chance to write up research findings for posters or papers.
Student Independence: The SURF student will have independence to execute daily experiments, with assistance as needed, and to analyze results for discussion with Dr. Vaughan. The student will be able to suggest experimental directions as dictated by findings and formulate plans for execution of ideas.