Method of target protein distribution detection in normal and disease-associated protein in thin tissue sections


Technology: Researchers at MUSC have developed a sensitive and reliable matrix- assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS) method for in situ reporting extracellular matrix (ECM) sequences localized to tissue, yet without prior knowledge of a specific epitope, increased sequence information compared to most antibody epitopes, and unbiased as to tissue type. This method allows, for the first time, direct detection of localized biochemical information related to extracellular matrix collagens and elastin proteoforms.


This is achieved through a new workflow using matrix metalloproteinase (MMP) and/or collagenase type (COLases) enzymes with MALDI IMS to access and report on spatial localization of collagen and elastin sequences in formalin-fixed, paraffin-embedded (FFPE) tissues. For example, the figure below shows MALDI IMS imaging results when collagenase type III is used in a liver tissue section with a tumor and necrosis compared to histological staining. On adjacent slides, LC-MS/MS proteomic analysis can be used to report sequence information of the collagen and elastin peptide sequences cleaved by enzymes. This novel method is applicable to any mammalian tissue, organ, or system during health or disease.



Overview: Collagens and elastin form the fundamental framework of all tissues and organs, and are tightly regulated in disease and health. Although critical proteins of organogenesis, remodeling and repair, and disease, the abundant post translational modifications (PTMs), genetic alterations, and suprastructural arrangements through cross-linking have created significant challenges in studying the role of changes within the tissue microenvironment. Both antibody staining and conventional mass spectrometry (MS) have not been fruitful in interpreting collagens and elastin sequence variation in the tissue microenvironment. Antibody reporting of collagens and elastin is  limited by in situ biochemical and structural modulation of collagens and elastin. MS proteomic workflows using common enzymes (trypsin, LysC, and ArgC) that target arginines and lysines, which are heavily modified in collagens and elastins, do not produce suitable targets for subsequent MS analysis. MALDI IMS is an imaging modality that uses mass spectrometry to map localization of proteins from thin tissue sections regardless of PTM or mutation. MALDI IMS methods that can localize collagen and elastin peptides using enzymes with high collagenase/elastin activity would allow for determining novel tissue features relevant to basic, translational and clinical research.


Applications: Higher sequence coverage than single antibodies, diagnosing and evaluating diseases such as cancer, identification of new biomarkers


Advantages:  Utilizing panels of ECM proteins for detection of disease states earlier and more reliably, new biomarkers identified

Key Words: MALDI, imaging mass spectrometry, extracellular matrix, paraffin-embedded tissue imaging, peptide imaging, proteomics, tissue imaging


Publication: Angel PM et al., (2017) Mapping Extracellular Matrix Proteins in Formalin-Fixed, Paraffin-Embedded Tissues by MALDI Imaging Mass Spectrometry. J Proteome Res. DOI: 10.1021/acs.jproteome.7b00713


Inventors: Peggi Angel and Rick Drake       

Patent Status:        Provisional filed 10.16.17              

MUSC-FRD Technology ID: P1777     

Licensing Status: Available for licensing  



Patent Information:
For Information, Contact:
MUSC Foundation for Research Development
Peggi Angel
Richard Drake
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