Dominick Centurioni
The Study of Membrane Microdomains Using Atomic Force Microscopy
G protein-coupled receptors (GPCR) are membrane proteins that are important to our physiological senses, neurological signal transduction, our immune system, and cellular processes like cell proliferation. The human follicle stimulating hormone receptor (hFSHR) is a G protein-coupled receptor important to the regulation of reproduction and other related processes. It has been speculated that lipid rafts could regulate signal transduction by manipulating the trafficking of a GPCR like hFSHR or by modulating the partners it can associate with at the cell membrane. To further examine the mechanism by which these rafts contribute to signal transduction, tapping mode atomic force microscopy was performed. Using this approach allowed us to generate high resolution images of cell membrane structures. Live cell imaging was performed on human epithelial cells to monitor changes in cell membrane microdomains after samples were treated with methyl-β-cyclodextrin (MBCD). MBCD removes the cholesterol component of the cell membrane, causing the dissociation of lipid rafts. For the hFSHR, this inhibits signal transduction. Based upon our research, we can conclude that MBCD had a disrupting effect on these cell membrane microdomains involved in the hFSHR signaling mechanism.
Russell Creed
Percieved Stress as the Basis for Salivary Cortisol Levels
Understanding the physiological response to stress in college students is an important goal for helping students maintain good psychological health during their academic careers. My hypothesis was that perceived stress would show a stronger correlation to salivary cortisol than either depression or anxiety. An additional hypothesis was that over an academic term students experience increasing amounts of perceived stress and salivary cortisol levels taken at the time of these stress tests will reflect the increased amount of stress. Three different self-reporting surveys, along with a brief questionnaire were used to measure the stress levels of students. These three tests were The Beck Depression Inventory (BDI), The State Trait Anxiety Inventory, and The Perceived Stress Scale. The PSS provides a good measure of the stress that people perceive in their life. To measure the salivary cortisol levels I utilized a passive drool collection and cortisol levels were measured by an enzyme linked immunosorbent assay (ELISA). Preliminary findings show that there is a positive correlation between perceived stress and the time of the academic term. Correlation with salivary cortisol could provide an interesting method to track student stress during the term and identify students who are at risk.
Maria Dzialo
Characterization of a putative caveolin interaction motif in the human follicle stimulating hormone receptor
Compartmentalization of signal transducing proteins into membrane microdomains is one explanation as to why cells are capable of producing rapid and efficient signaling responses. These microdomains, or membrane rafts, provide scaffolding for cell signaling molecules to come into close proximity with other effectors. Follicle stimulating hormone receptor (FSHR) is a G protein-coupled receptor shown to localize in membrane rafts, potentially in a raft subtype called caveolae. Previous work in this lab has shown that human FSHR co-immunoprecipitates with caveolin, a scaffolding protein that serves as the molecular marker for caveolae. Presence of a putative caveolin binding motif (ΦXΦXXXXΦXXΦ) in the fourth transmembrane domain of hFSHR suggests that the receptor interacts with caveolin at this site; this interaction could prove necessary for hormone binding, signal transduction, or membrane trafficking. We created two mutant receptors with point mutations within the motif (F481L and F489L). Preliminary data suggests that wild-type receptor and mutant receptor F481L interact with caveolin while mutant receptor F489L does not. We have also found that receptor F481L is still capable of binding to hormone; F489L is unable to bind to hormone suggesting that caveolin may be essential for hFSHR’s ability to bind ligand or for trafficking to the cell membrane.
Ann Keller
Differences in Stress Between Student Athletes and Non-athletes
For years, it has been understood that exercising helps to cope with mental stress. Based on this presumption, this study set out see if there was a difference in stress levels between student athletes and student non-athletes. It was hypothesized that with the amount of exercise that student athletes endure, they would cope differently with stress than student non-athletes, who do not have such a strict exercise regimen. To test this theory, athlete participants were recruited from the Union College hockey teams and non-athletes were recruited from the general Union College student population. Using self reported surveys, individuals in both groups recorded their stress levels for four different weeks throughout the course of the trimester (specifically weeks 1, 5, 7, and 10). Obvious differences in stress levels between the two groups became apparent upon analysis. While average stress levels of the non-athlete population trended upwards throughout the term, the average stress levels of the athlete population began high in week 1 as compared to the non-athletes but remained constant throughout the term. Comparing the results from the surveys to salivary cortisol (a stress hormone) levels could serve as a supplementary method for tracking this comparison in stress.
Meredith Nearpass
The Investigation of the Function of Plasma Membrane Domains in Follicle Stimulating Hormone Signal Transduction
The human reproductive hormone, follicle stimulating hormone (hFSH) acts in females on granulosa cells in the ovaries to stimulate egg maturation. In males hFSH promotes spermatogenesis by stimulating Sertoli cells of the testes. The human FSH receptor (hFSHR) is a G protein-coupled receptor that is known to stimulate the production of cAMP as well as the p44/42 MAP kinase pathway. The multiple signaling responses of this hormone receptor complex may be due to its location in special membrane domains known as lipid rafts. Lipid rafts are rigid domains of the plasma membrane that are enriched in cholesterol, glycolipids and sphingomyelin. Previous studies have shown that disruption of these domains by removing cholesterol inhibits the hFSHR cAMP response but interestingly not the p44/42 MAPK pathway activation. My research investigated if degradation of lipid rafts by an enzyme called sphyingomyelinase (SMase) caused any changes in the signaling ability of hFSHR. SMase breaks down sphingomyelin, consequently destabilizing the lipid raft. Epithelial cells expressing hFSHR were pretreated with SMase followed by hFSH treatment and signal transduction was measured. Surprisingly, SMase did not inhibit cAMP production the same way removal of cholesterol did. Further experiments will be required to elucidate this difference.
John Peters
Relation of Microdomain Residency to the Function of the Follicle Stimulating Hormone Receptor
Human follicle stimulating hormone (hFSH) is a glycoprotein hormone that acts through a cell surface G protein-coupled receptor. Receptor activation stimulates cAMP production to promote normal gamete formation in both males and females. In men, FSH is responsible for stimulating spermatogenesis by stimulating the proliferation of Sertoli cells. In women, FSH functions with luteinizing hormone (LH) to regulate the menstrual cycle and to promote oocyte maturation in the ovary. Understanding and developing techniques to control the signal transduction pathway of the follicle stimulating hormone receptor (hFSHR) may lead to novel in vitro fertilization and contraceptive techniques. Our hypothesis is that the hFSHR signaling complex is compartmentalized within plasma membrane microdomains known as lipid rafts. The goal of this study was to investigate the role of lipid rafts in the function of hFSHR. A cholesterol-withdrawing agent called methyl-b-cyclodextrin was used to disrupt lipid rafts. Western blotting techniques were then used to analyze the activation of hFSHR downstream pathways, p38-MAP kinase and p44/42-MAP kinase. Cholesterol depletion resulted in the maintenance of p44/42 activity but interfered with activation of the p38 pathway. This suggests that these pathways have different mechanisms of activation and may represent a potential opportunity for therapeutic intervention.
Genevieve St. Hilaire
Quality Versus Quantity: Serum AMH Levels Predict Oocyte Viability and Pregnancy Success in Women Undergoing IVF
Anti-Müllerian Hormone (AMH) is a TGF-β protein essential to sexual differentiation during embryogenesis of the fetal male. Although AMH is best known for inducing apoptosis in target tissue, recent studies suggest that this hormone positively regulates the viability of pre-ovulatory oocytes by preventing over-selection by Follicle-Stimulating Hormone (FSH). This study has been a retrospective analysis of patient records at Albany IVF and Infertility, in which serum AMH levels were correlated with oocyte quality and pregnancy success for women undergoing In-Vitro Fertilization (IVF). As AMH reduces oocyte sensitivity to excessive FSH stimulation, it was hypothesized that median serum AMH levels would correspond with good quality oocytes and pregnancy success. Results thus far suggest that AMH levels in the 75th-100th percentile correlate with good quality blastocyst formation and successful pregnancy after IVF. Overall, this study reveals AMH to be a mediator of oocyte maturation and a key marker that may predict patient response to assisted reproductive technology (ART) procedures. Establishing AMH as a routine and relevant measurement in infertility clinics may help to alleviate the fiscally and emotionally taxing nature of ART for patients and practitioners.
Honorary Members:
Sophomore Scholars
- Jillian Coffey ’12
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