Direct profiling of myelinated and demyelinated regions in mouse brain by mass spectrometry imaging

Abstract

One of the newly developed imaging mass spectrometry (IMS) technologies utilizes matrix-assisted laser desorption/ionization(MALDI) mass spectrometry to map proteins in thin tissue sections. In this stuy, we evaluated the power of MALDI IMS as we developed it in our (Bruker) MALDI TOF(Reflex IV) and TOF-TOF (Ultraflex II) systems to study myelin patterns in the mouse central nervous system under normal and pathological conditions. MALDI IMS was applied to assess myelin basic protein(MBP) isoform-specific profiles in different regions throughout the mouse brain. The distribution of ions of m/z 14,144 and 18,447 displayed a striking resemblance with white matter histology and were identified as MBP isoform 8 and 5, respectively. In addition, we demonstrated a significant reduction of the MBP-8 peak intensity upon MALDI IMS analysis of local ethidium bromide-induced demyelinated brain areas. Our MS images were validated by immunohistochemistry using MBP antibodies. This study underscores the potential of MALDI IMS to study the contribution of MBP to demyelinating diseases.