Laura Puentes, '15

Laura Puentes, '15

Cohort

2015

Biography

Laura Puentes was born in Bogota, Colombia and raised in Mt. Dora, Florida. She has an Associate's degree from Valencia Community College. She is pursuing a Bachelor's degree in Biotechnology and a minor in Anthropology. Knowing first-hand the difficulties that come with learning a new language, she developed a community service program called "Bridges" in order to help Spanish speaking individuals with translation services. Laura is interested in conducting research in drug discovery and development. She plans to obtain her Ph.D in Biomedical Engineering and Biotechnology and become a research scientist.

Undergraduate Major

Biotechnology

Future Plans

Ph.D. in Biomedical Engineering; Biotechnology

Research

Site-Specific Structural Changes in Unmodified and Pyroglutamylated Amyloid Beta Peptide by Idotope-Edited FTIR Conducted at the University of Central Florida Mentor: Greg Goldblatt1, Jason O. Matos2, Jeremy Gornto3 Biomedical Sciences Graduate Program, University of Central Florida, Orlando Abstract: Amyloid beta-peptide (Abeta) forms cytotoxic assemblies that contribute to Alzheimer's disease. Recent evidence indicates that prefibrillar aggregates and not the fibrillar deposits exert the main toxic effect. In addition, naturally occurring N-terminally truncated and pyroglutamylated peptide (pE-Abeta) displays augmented cytotoxicity by an unknown mechanism. This study examines the conformational changes in both unmodified Abeta and pE-Abeta upon exposure to an aqueous environment. FTIR and circular dichroism were used to identify alpha-helix-to-beta-sheet conformational transitions of both peptides during aggregation. To gain site-specific structural information, the peptides were 13C,15N-labeled at residues 16-18 (KLV) or 36-39 (VGGV), followed by FTIR analysis. The peptides dried from hexafluoroisopropanol were alpha-helical (amide I peak at 1660-1657 cm-1) and showed negligible intensity of the labeled segments around 1615 cm-1, suggesting that in alpha-helical conformation the labeled amide groups behave like isolated oscillators. Upon addition of aqueous buffer (pH 7.2) both peptides rapidly adopted beta-sheet structure (amide I peak at 1637-1629 cm-1), with disproportionally prominent components around 1604-1597 cm-1 generated by the labeled segments. The intensity and the frequency of the amide I mode of the isotope-labeled segments suggest 12C-13C vibrational coupling, consistent with formation of antiparallel beta-sheet structures. Moreover, the amide I contours of the peptides under near-physiological and low ionic strength conditions were significantly different; both peptides exhibited an increased alpha-helical and decreased beta-sheet propensity under low ionic strength conditions, indicating a strong influence of the ionic strength on the aggregation kinetics and accompanying structural changes. Ongoing studies focus on structural differences between the unmodified Abeta and pE-Abeta peptides as well as their mutual structural effects when combined at various molar ratios, in an attempt to understand the structural basis of the elevated cytotoxicity of pE-Abeta.

Summer Research

Functional Reversal: Short-Term and Long-Term Variations in Vascular Endothelium-Derived Reactive Oxygen Species Conducted at Brown University part of Leadership Alliance summer research program. Mentor: Ruhul Abid M.D, Ph.D Brown University Abstract: Understanding the time-dependent functional reversal in reactive oxygen species (ROS) is essential in order to develop therapeutic modalities for cardiovascular disease. The aim of our project is to focus on the transient exposure of reactive oxygen species (ROS) in vascular endothelium versus chronic exposure, and to understand the vascular functional variations by ROS that are contingent on its temporal presence. Chronic oxidative stress leads to the deactivation of mitochondrial superoxide dismutase (SOD2) and a reduction in mitochondrial membrane potential. We hypothesize that the deactivation of SOD2 leads to increased mitochondrial ROS production resulting in mitochondrial damage and decreased coronary vasodilation. Our laboratory found that endothelium-dependent coronary vasodilation improved in mice that overexpressed NOX2, a component of the ROS generating NADPH oxidase complex, for a period of 4-12 weeks (short-term). It is well established that long-term (12-16 weeks) overexpression of NOX2 results in chronic oxidative stress, leading to the disruption of nitric oxide (NO) synthesis. We generated a double transgenic TET ON/OFF mouse model to modulate endogenous ROS levels via the overexpression of NOX2. Based on our results we were able to confirm that NO and SOD2 increase during short-term ROS production due to the activation of the AMPK-eNOS pathway. Our findings further revealed that heightened levels of ROS, which are often associated with endothelial dysfunction and cardiovascular problems in advanced age, can play an acutely protective role in endothelial homeostasis by inducing eNOS activation and NO production during short-term increase. Future research in our laboratory will focus on measuring NO and mitochondrial ROS levels during long-term oxidative stress and analyze its effects on endothelial function.

Summer Research Institution

Brown University

Disciplines

Biomedical Engineering and Bioengineering

Laura Puentes, '15


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