From left: Steve Barnes, Steve Watts, Miranda Collier, Janusz Kabarowski and David Graves with the Bruker Autoflex Speed MALDI-TOF/TOF mass spectrometer An interdisciplinary collaboration at the University of Alabama at Birmingham recently established a research method that has expanded the institution’s already robust capacity for discovery, addressing a need that will aid in critical initiatives addressing a variety of diseases including cancer, chronic inflammatory autoimmune diseases and age-related degenerative diseases.
The matrix-assisted laser desorption/ionization imaging mass spectrometry, or MALDI-IMS, method is a powerful tool for investigating the distribution of molecules within biological systems through the direct analysis of thin tissue sections.
Biomedical research is typically aimed at answering the fundamental questions of how, when, where and why important biological processes occur in the body and determining their relevance to human disease.
School of Medicine Department of Microbiology Associate Professor Janusz Kabarowski, Ph.D., says experimental tools have been available for determining how, when and why particular tissue or organ molecules act in the body; but he has not had sophisticated enough methods to determine exactly where they are produced or where they accumulate to perform their important functions.
“The uncontrolled production of a biologically active molecule that is normally produced in response to defined signals to orchestrate changes in the behavior of cells required for the proper function of tissues can lead to abnormal cellular behavior,” Kabarowski said. “The result can be life-threatening diseases such as cancer or autoimmune disease.”
Fragmentation analyses identify molecules structurally via MALDI-IMS. Here a zebrafish eye lens shows different lipids in blue and red.Implications in cancer research are extensive, for example, as MALDI-IMS can provide important spatial characterization of biomarkers or drugs in tumors, surrounding tissues and non-involved organs.
The method uses a common type of mass spectrometry called matrix-assisted laser desorption/ionization time of flight, or MALDI-TOF, to visualize small molecules directly in frozen sections such as those taken in research laboratories and clinics for pathological, histological or immunohistochemical analysis.
It took faculty and technology from around campus to make MALDI-IMS a reality at UAB.
“We combined our collective knowledge and physical assets to open new research opportunities,” said David Graves, professor and chair of the Department of Chemistry, who was party to the collaboration that included departments in the College of Arts and Sciences and School of Medicine, as well as the Targeted Metabolomics and Proteomics Laboratory.
Students like Miranda Collier, an undergraduate chemistry major in the University Honors and Chemistry Scholars Fellowship programs, often benefit from UAB’s cutting-edge technology. In the case of the MALDI-IMS, UAB benefited from her involvement in return.
Collier’s work among diverse researchers across departments allowed her to gain valuable experience and served as a model for the new method.
Kabarowski and Collier first assembled the necessary apparatus, including items custom-built by the UAB Research Machine Shop, to prepare tissue sections for imaging analysis, then used a Bruker Autoflex Speed MALDI-TOF/TOF mass spectrometer in the Department of Chemistry mass spectrometry facility.
Computer software was then purchased that allows the ability to gather data on the relative amounts and precise localizations of molecules in the tissue.
Distinct fragmentation patterns of different lipids (red and green) can be seen in a mouse kidney using MALDI-IMS.“Data is processed so that the distribution of any molecule detected can be visualized to give an image,” said Collier, a Barry M. Goldwater Scholar. “This is important because it tells us exactly where in a tissue a particular molecule is located after we have determined by conventional mass spectrometry that its overall levels are changed, for example, by disease, aging or drug treatment.”
Kabarowski and Steve Barnes, Ph.D., professor of pharmacology and toxicology and director of the UAB Targeted Metabolomics and Proteomics Laboratory, helped Collier determine how an important family of small molecules (lipids) changes with age in the eye lens. Working with Steve Watts, Ph.D., professor of biology and co-director of the UAB Zebrafish Research Facility, they examined the lipid composition of lenses from young and old zebrafish to identify lipid molecules that increase or decrease with age. Such changes in lipids may be involved in diseases like cataracts, which typically affect the aging population.
A 5600 Triple-TOF mass spectrometer was then used to find several interesting lipid molecules that were changed with age in the zebrafish lens to determine where exactly in the lens they are localized.
“The ability to obtain spatial information in different tissue types using this imaging method has implications with respect to many areas of fundamental and clinical research,” Barnes said. “It is exciting when researchers from different disciplines team to advance science, and it makes it all the more special that our students benefit directly with valuable experience.”