The MSPIRE research that I have engaged in involves the study of oxidized phospholipids by MALDI-MS. My research focuses on multi-stage tandem mass spectrometry (MSn) and mass spectrometric imaging (MSI) of phospholipid oxidation products in oxidatively stressed nervous tissues. These techniques have been used to characterize chemical changes in phospholipid standards following in vitro oxidation and in tissues from Sprague-Dawley rats dosed with dichloroacetate. Both long-chain and short-chain phospholipid oxidation products have been identified. As seen in the figure below, MALDI-MS shows the presence of multiple oxygen additions to the PC (16:0/18:2) standard following in vitro oxidation. For long-chain products, multi-stage tandem MS has been used to determine the location of the oxygen additions. Also, MSI has been used to evaluate the localization of these lipid oxidation products in spinal cord tissue. We are currently extending these studies to characterize reactive aldehydes such as HNE and MDA in tissues with oxidative damage.

Figure. In vitro oxidation of PC. MS spectra of PC (16:0/18:2) standard following exposure to light. Methylene Blue was added (a) to produce singlet oxygen. Water was added as a control (b). Mass shifts of 16 amu are observed, which are indicative of oxygen additions.