Investigation of 10% Neutral Buffered Formalin and Other Similar Aqueous Tissue Washes for Mass Spectrometry Imaging of Crustacean Neuropeptides

ABSTRACT: Neuropeptides are low abundant signaling molecules that modulate almost every physiological process and dysregulation of neuropeptides is implicated in disease pathology. Mass spectrometry (MS) imaging is becoming increasingly useful for studying neuropeptides as new sample preparation methods for improving neuropeptide detection are developed. In particular, MS imaging washes have shown to be quick and effective at increasing the number of detectable neuropeptides. Treating tissues with solvents typically results in the gain and loss of detection of analytes, and characterization of these wash effects is important for studies targeting sub-classes of neuropeptides. In this communication, we apply aqueous tissue washes that contain sodium phosphate salts, including 10% neutral buffered formalin (NBF), on crustacean brain tissues. The choice of 10% NBF was motivated by previous studies showing neuropeptides can escape formalin-mediated crosslinking during formalin-fixation and therefore able to be detected using MS imaging from formalin-fixed paraffin-embedded (FFPE) tissue without applying antigen retrieval. Our optimized method resulted in complimentary identification of neuropeptides between washed and unwashed, control tissue, indicating that our wash protocol may be used to increase neuropeptide identifications. Finally, we show that identical neuropeptides were detected between tissues treated with 10% NBF and an aqueous sodium phosphate solution, implying that formaldehyde did not improve neuropeptide detection when compared with detection from our salt solution wash protocol.

INSTRUMENT(S): LTQ Orbitrap

ORGANISM(S): Callinectes Sapidus (ncbitaxon:6763)

SUBMITTER: Lingjun Li  

PROVIDER: MSV000085824 | MassIVE | Fri Jul 24 12:50:00 BST 2020

REPOSITORIES: MassIVE