On-tissue identification of insulin: In situ reduction coupled with mass spectrometry imaging
ABSTRACT The aim of this study was to use on-tissue reduction followed by MALDI-MS imaging (MSI) to identify an m/z 5812.85 peak, which is over-expressed in healthy human pancreatic tissue compared with type one Diabetes (T1D) tissue.
A major constraint of MALDI-MSI is identification of compounds with m/z ≥4000. On-tissue reduction using tris (2-carboxyethyl) phosphine (TCEP) breaks the inter-domain disulphide bonds generating low-molecular-weight peptides amenable to direct MS/MS analysis. Pancreatic tissues from healthy (n=4) and diabetic subjects (n=4) were profiled by MALDI-MSI with/without reduction.
On-tissue reduction resulted in the loss of the over-expressed 5812.85 m/z peak and the simultaneous appearance of a 3430.664 m/z peak in healthy tissues. The latter peak presumably derived from the 5812.85 m/z peak was identified as the insulin B chain by MS/MS. MALDI-MSI images show that both the 5812.85 insulin peak before reduction and the 3430.664 peak after reduction co-localized with the healthy pancreatic islets.
On-tissue reduction followed by MALDI-MSI resulted in the identification of insulin and localization of pancreatic islets of langerhans. The approach will be useful in the future identification of novel therapeutic molecular targets to β-cells lost during type one diabetes.
SourceAvailable from: Martha Campbell-Thompson[Show abstract] [Hide abstract]
ABSTRACT: The Juvenile Diabetes Research Foundation (JDRF) Network for Pancreatic Organ Donors with Diabetes (JDRF nPOD) was established to obtain human pancreata and other tissues from organ donors with type 1 diabetes (T1D) in support of research focused on disease pathogenesis. Since 2007, nPOD has recovered tissues from over 100 T1D donors and distributed specimens to approximately 130 projects led by investigators worldwide. More recently, nPOD established a programmatic expansion that further links the transplantation world to nPOD, nPOD-Transplantation; this effort is pioneering novel approaches to extend the study of islet autoimmunity to the transplanted pancreas and to consent patients for postmortem organ donation directed towards diabetes research. Finally, nPOD actively fosters and coordinates collaborative research among nPOD investigators, with the formation of working groups and the application of team science approaches. Exciting findings are emerging from the collective work of nPOD investigators, which covers multiple aspects of islet autoimmunity and beta cell biology.Current Diabetes Reports 10/2014; 14(10):530. DOI:10.1007/s11892-014-0530-0 · 3.38 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: Pancreatic cancer is a highly lethal disease that is difficult to diagnose and treat. The advances of proteomics technology, especially quantitative proteomics, have stimulated a great interest to apply this technology for pancreatic cancer study. A variety of tissue proteomics approaches have been applied to investigate pancreatic cancer and the associated diseases. These studies were carried out with various goals, aiming to better understand the molecular mechanisms underlying pancreatic tumorigenesis, to improve therapeutic treatment and to identify cancer associated protein signatures, signaling events as well as interactions between cancer cells and tumor microenvironment. Here, we provide an overview on the tissue proteomics studies of pancreatic cancer reported in the past few years in light of discovery and technology development.Proteomics 02/2013; 13(3-4). DOI:10.1002/pmic.201200319 · 3.97 Impact Factor
Pediatric Diabetes 12/2013; DOI:10.1111/pedi.12097 · 2.13 Impact Factor