Title

Identification Of Post-Translationally Modified (O-GlcNAc) Hepatic Proteins In Fasted And Re-Fed Mice

Author(s)

Mattie Piness

School Name

South Carolina Governor's School for Science and Mathematics

Grade Level

12th Grade

Presentation Topic

Chemistry

Presentation Type

Mentored

Mentor

Mentor: Lauren Ball, Department of Pharmacology, Medical University of South Carolina

Abstract

Diabetes mellitus type 2 affects over eight percent of all Americans. However, despite the prevalence of the disease, much is unknown. Previous studies have shown that O-linked N-acteylglucosamine (O-GlcNAc) modification of proteins increases in frequency when blood glucose levels are elevated. We sought to determine which proteins receive the O-GlcNAc modification as well as the function of those proteins in response to hyperglycemia. To identify the modified proteins, we created a unique methodology based on a combination of established techniques. Samples from a control group of fasted mice modeled lower blood glucose levels and from an experimental group of fasted then re-fed mice modeled higher blood glucose levels. Dimethyl labeling was applied to distinguish the experimental and control mice. A lectin weak affinity chromatography (LWAC) column was used to isolate O-GlcNAc modified proteins. The identity of the modified proteins was determined with a combination of heavy and light mass spectrometry. The initial steps of this novel protocol were successful. Dimethyl labels appeared on the mass spectra and enabled us to confirm an increase in O-GlcNAc modification in response to glucose in the re-fed mice. Future studies will utilize this labeling technique in combination with chromatography and mass spectrometry with larger sample sizes to further understand the role of O-GlcNAc modification in Diabetes mellitus.

Start Date

4-11-2015 9:45 AM

End Date

4-11-2015 10:00 AM

COinS
 
Apr 11th, 9:45 AM Apr 11th, 10:00 AM

Identification Of Post-Translationally Modified (O-GlcNAc) Hepatic Proteins In Fasted And Re-Fed Mice

Diabetes mellitus type 2 affects over eight percent of all Americans. However, despite the prevalence of the disease, much is unknown. Previous studies have shown that O-linked N-acteylglucosamine (O-GlcNAc) modification of proteins increases in frequency when blood glucose levels are elevated. We sought to determine which proteins receive the O-GlcNAc modification as well as the function of those proteins in response to hyperglycemia. To identify the modified proteins, we created a unique methodology based on a combination of established techniques. Samples from a control group of fasted mice modeled lower blood glucose levels and from an experimental group of fasted then re-fed mice modeled higher blood glucose levels. Dimethyl labeling was applied to distinguish the experimental and control mice. A lectin weak affinity chromatography (LWAC) column was used to isolate O-GlcNAc modified proteins. The identity of the modified proteins was determined with a combination of heavy and light mass spectrometry. The initial steps of this novel protocol were successful. Dimethyl labels appeared on the mass spectra and enabled us to confirm an increase in O-GlcNAc modification in response to glucose in the re-fed mice. Future studies will utilize this labeling technique in combination with chromatography and mass spectrometry with larger sample sizes to further understand the role of O-GlcNAc modification in Diabetes mellitus.