SUP Program: SURF

Presentation Time: 9:25-9:45

Home University: UNC-Chapel Hill

Research Mentor: Dr. Todd Cohen, Neurology Department

Program: SURF

Research Title: Investigating the Phosphorylation of HDAC6 in Protection Against Alzheimer’s Disease

Alzheimer’s disease (AD) is characterized by the accumulation of waste proteins, often referred to as tangles, which are considered the primary contributor to neuronal death. The main component of these tangles is tau protein which undergoes modifications that correlate with cognitive decline. Of these modifications, lysine acetylation is particularly relevant as it strongly accelerates tangle formation. Histone deacetylase 6 (HDAC6) is known to remove acetyl groups from tau protein, and thus, serves as a potential modifier for AD pathogenesis. Here, we hypothesize that HDAC6 activity is regulated by specific kinases via phosphorylation at Ser-22. In this study, we performed subcellular fractionation, co-immunoprecipitation, and immunofluorescence approaches using HEK-293 cells. We further investigate which kinases most effectively interact with and phosphorylate HDAC6, and analyze the downstream events of HDAC6 phosphorylation, such as nuclear-cytoplasmic shuttling. Our results showed that the Parkinson’s disease (PD)-relevant kinase LRRK2, and GSK-3, a kinase long implicated in AD progression, exhibited potent kinase activities towards HDAC6 and mediated subcellular translocation of HDAC6. This study highlights potential upstream enzymes of HDAC6 and the succeeding events of HDAC6 phosphorylation. Further investigation of these kinases in disease models could reveal alternative strategies for AD treatment and potentially bridge gaps between AD and PD pathologies.

Presentation Time: 9:50-10:10

Home University: UNC-Chapel Hill

Research Mentor: Leslie Hicks, UNC Chemistry

Program: SURF

Research Title: Prediction and discovery of small open reading frame encoded polypeptides from Enterococcus faecalis

Recent multi-omic efforts have facilitated the discovery of unannotated small open reading frame encoded polypeptides (SEPs). SEPs are small proteins (< 50 amino acids in length) representing an underexplored class of biomolecules due to the lack of genome prediction software and challenges in identification. However, increasing evidence demonstrates that SEPs play critical roles in cellular processes and serve diverse microbiological functions. Some known SEPs exhibit functions such as promoting pathogenesis, stabilizing protein complexes, and containing antimicrobial properties. Enterococcus faecalis is a ubiquitous member of healthy human gut microbiota with duality as a probiotic commensal as well as an opportunistic pathogen. The absence of pathogen-specific genes or pathogen-specific features suggests that E. faecalis’s virulence is determined by the host-microbe interaction. To this end, we hypothesize that the expression of various SEPs associate with E. faecalis’ transition from a commensal to pathogenic in changing environments. Herein, a six-frame genome translation and smORFinder were used for creating a predicted E. faecalis SEP database. In vivo translation of predicted SEPs is pursued via mass spectrometry.

Presentation Time: 10:15-10:35

Home University: UNC-Chapel Hill

Research Mentor: Matthew Redinbo, Chemistry

Program: SURF

Research Title: Investigating the Structural and Functional Diversity of Azoreductases Across the Human Intestinal Microbiome

Azo-linked compounds are ubiquitous across foods, textiles, paints, and cosmetics, as well as prodrugs that treat Inflammatory Bowel Disease (IBD). Azoreductases (AzoRs) are a family of enzymes produced by bacteria residing in the human gastrointestinal tract that reductively cleave these azo linkages; however rates of activity differ dramatically depending on the species of origin. Through metagenomic analyses, our lab has identified over 100 putative azoreductases across the human gut microbiome. In this study, we compare two novel azoreductases from Klebsiella pneumoniae (KpAzoR) and Clostridium marseille (CmAzoR) to the well-characterized Escherichia coli azoreductase A (EcAzoRA). We determined the catalytic efficiencies of these enzymes in metabolizing four sterically diverse azo dyes: methyl red, amaranth red, acid orange 7, and brilliant black. Then, we used in silico modeling to compare the structures of these enzymes in the context of their observed activities. We show disparate catalytic efficiencies across our panel of azoreductases and identify key active site differences that may account for the observed differences in activity. In future studies, we aim to characterize more azoreductases and their activities with prodrug substrates to pinpoint the azoreductases integral to the treatment of IBD. Exploring these structural and functional differences can help us better understand how azoreductases differentially activate prodrugs and may enable the manipulation of these differences for targeted therapeutics.

Presentation Time: 10:40-11:00

Home University: UNC-Chapel Hill

Research Mentor: Shu Wen Ng, Nutrition

Program: SURF

Research Title: Urban and Rural Purchasing Patterns of SNAP Participants in North Carolina

Urban and rural residents have different food environments and different resources available to them. Research has shown that healthy foods are more likely to be more expensive in rural areas and less accessible. SNAP beneficiaries may face particular barriers from purchasing healthy foods due to their limited budgets. We used existing de-identified transaction data from a large grocery chain with nearly 500 stores throughout North Carolina to look at SNAP purchases from rural vs urban stores from October 2019 through December 2020. We are interested in understanding if rural stores contribute to more/less healthy purchases (fruits and vegetables with and without additives) or unhealthy purchases (sugary beverages) by SNAP participants compared to urban stores. We will also investigate if these differences widened or narrowed since COVID. We have organized the large amount of transaction level data, conducted data diagnostics, layered on auxiliary data and created relevant measures/variables for analyses. We will be conducting descriptive and regression-based modeling over the next month.

Presentation Time: 11:05-11:25

Home University: UNC-Chapel Hill

Research Mentor: Ian Davis, UNC School of Medicine

Program: SURF

Research Title: Exploring Synergistic Effects of Small Molecules in Ewing sarcoma

Ewing sarcoma, the second most common bone cancer in children and young adults, is driven by a chromosomal translocation that generates the critical fusion oncoprotein EWS-FLI11. EWS-FLI1 binds to specific genomic loci where it increases chromatin accessibility. EWS-FLI1 results in nucleosome depletion at targeted sites, and silencing EWS-FLI in cells results in decreased chromatin accessibility at EWS-FLI1 target sites. Previously, the Davis Lab demonstrated that small molecules can also decrease chromatin accessibility at EWS-FLI1 target sites (Pattenden et al). Furthermore, a small molecule modulator of EWS-FLI1 protein stability, 7ai, has been recently identified, but its effects on chromatin accessibility have not been as well characterized (Su et. al). As these compounds have different mechanisms of action, we asked whether synergy might be achieved by combining compounds with effects on chromatin accessibility . Using FAIRE-qPCR, I will characterize the effects of 7ai on chromatin accessibility at EWS-FLI1 target loci alone and in combination with UNC0621 and Varinostat, small molecules that decrease chromatin accessibility at these sites. As these compounds also have effects on Ewing sarcoma cell proliferation, I will use two proliferation assays, the WST assay and the real-time microscopy using the Incucyte to assess the effect of the compounds singly and in combination on the metabolic activity and proliferation of Ewing sarcoma cells, respectively. Ultimately, this drug discovery research not only aids to understand the mechanism of EWS-FLI1, but it also has the possibility to increase Ewing Sarcoma survival rates

Presentation Time: 11:55-12:15

Home University:

Research Mentor: Rachel Force, Psychiatry

Program: SURF

Research Title: Use of Transcranial Alternating Current Stimulation for the Treatment of Major Depressive Disorder

Major depressive disorder (MDD) is a common, severe psychiatric illness that has a lifetime prevalence of about 16.6% in adults. Patients with major depression respond to antidepressant drugs; however, approximately one-third of these patients remain treatment-resistant after adequate trials of multiple monoamine-based therapies. Treatment-resistant depression is a difficult condition to treat and has an impact on medical comorbidities such as heart disease, cancer, thyroid disease, manifestations of impending relapse, and genetic vulnerability. To combat this, we wanted to further explore the efficacy of alternative treatment methods with transcranial alternating current stimulation (tACS).

MDD has been associated with increased alpha oscillations (8-12 Hz) in the left dorsolateral prefrontal cortex. Therefore, targeting and reducing alpha oscillations in this area could prove beneficial to patients with MDD. Targeted stimulation modalities, such as tACS, can directly engage and selectively modulate oscillations through the application of weak electric currents to the scalp. In addition, tACS has mild side effects, and no serious adverse events have yet been reported. A recent pilot study showcased the preliminary efficacy of tACS to decrease alpha oscillations, but the neurophysiological mechanism of action of how tACS caused this change is still unclear.

This presentation will showcase how we hope to better understand the mechanism of action of tACS in MDD patients. This can be primarily understood with high-density EEG measurements taken before and after every stimulation session. For this study, eligible patients will participate in 5 consecutive 40-minute tACS stimulation sessions, with either sham or 10Hz (alpha) stimulation. In addition to the stimulation session, I will help collect eyes open Resting-State EEG (RSEEG) recordings immediately before and after the 40-minutes of stimulation. This will help determine the immediate after-effects of tACS on brain activity, specifically on alpha oscillation power. If a direct relationship between tACS and alpha power is established, then noninvasive therapies can be considered as a reliable treatment option to alleviate symptoms several symptoms in MDD patients.

Presentation Time: 2:45-3:05

Home University: UNC-Chapel Hill

Research Mentor: Anthony Zannas, Psychiatry

Program: SURF

Research Title: The Relation Between Stress-Induced Epigenetic Changes and Cell Morphology

Historically, cellular morphology has been described using non-specific qualitative language and example images rather than quantitative data, limiting its investigation. The novel technologies ilastik and CellProfiler have emerged to solve this issue and allow for the high-throughput analysis of images to yield quantitative metrics such as cell area, perimeter, circularity, and branching using artificial intelligence (AI)-based cell recognition. Here, we created an ilastik and CellProfiler pipeline that focuses on the morphological measurement of IMR-90 fetal lung fibroblasts using composite images generated by the overlay of transmission microscopy and DAPI nuclear staining images. This pipeline has been utilized to compare the stress-based morphological changes induced by cortisol treatment of cells at a physiological level of 100 nm. Stressed and control groups do not differ in cell area, circularity, or perimeter. However, the stressed cells have a shorter average length per projection per cell. Further work is being done to correlate these morphological changes with known epigenetic changes, and to examine the influence of proliferation on them. Broadly, this pipeline is easily expandable to other cell types, meaning that many more morphological changes stand to be investigated.