Clinical Mass Spectrometry
There are currently several protein biomarkers used in the medical field to diagnose cancer. Among these are PSA for prostate cancer and CA125 for ovarian cancer. CA125 is a mucin glycoprotein which is known to have a wide variety of oligosaccharides attached. Our group has set out to identify these oligosaccharides. The first step is to obtain cell lines from various cancers and determine the types of biomolecules observed. This will allow for the creation of a protocol which can then be applied to patient serum samples.
An example of the peaks found in normal serum An Example of the peaks found in patient serum
Project 2: Application of High Mass Accuracy Peptide Mass Fingerprinting to the Proteomic Analysis of a Human Neurodegenerative Disease
While the exceptional mass accuracy attainable with Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) has been shown tremendously advantageous in the identification of proteins by peptide mass fingerprinting (PMF), remarkably few applications of this approach to the proteomic analysis of disease have been reported to date. Our research in this area is concerned with elucidating the protein compliment of the neuronal and astrocytic intranuclear inclusions characteristic of fragile X-associated tremor/ataxia syndrome (FXTAS), a human neurological disorder recently recognized by our collaborators in Dr. Paul Hagerman’s group at the School of Medicine. While the inclusions are not themselves thought to be pathogenic, it is believed that the development of these inclusions is linked to the fundamental events that incite FXTAS onset; thus, knowledge of the inclusion composition is potentially revealing of the underlying processes that contribute to the onset of the disease.
Our analytical scheme is depicted in the figure below. Inclusions are isolated from the post-mortem brain tissue of FXTAS patients and subjected to separation by two-dimensional gel electrophoresis (isoelectric focusing followed by SDS-PAGE). The 2-D gels are visualized using Sypro Ruby, and protein bands are excised for in-gel tryptic digestion. In-gel digests are purified purified, and mass spectral analysis is performed by MALDI-FTICR-MS with internal mass calibration. PMF analysis is performed using MASCOT (www.matrixscience.com). To date, several protein constituents of the inclusions have been identified with high confidence based on accurate mass analysis of tryptic peptides in tandem with protein database interrogation.
