Quantitative Mass Spectrometry incorporates collaborative projects in which the Mass Spectrometry Group provides quantitative information about, typically, small molecules by GCMS, LCMS and LCMSMS or a combination. We currently have several major collaborations underway. 1) With the Zeldin Lab quantitating arachidonic acid metabolites that are relevant to inflammatory, vasodilatory, endothelial protective and post-ischemic cardioprotective effects. We provided quantitative information for a project on epoxyeicosatrienoic acids (EETs), lipid mediators produced by cytochrome P450 epoxygenases, regulate inflammation, angiogenesis, and vascular tone. Despite pleiotropic effects on cells, the role of these epoxyeicosanoids in normal organ and tissue regeneration remains unknown. EETs are produced predominantly in the endothelium. Normal organ and tissue regeneration require an active paracrine role of the microvascular endothelium, which in turn depends on angiogenic growth factors. The hypothesis of this project is that endothelial cells stimulate organ and tissue regeneration via production of bioactive EETs. To determine whether endothelial-derived EETs affect physiologic tissue growth in vivo, genetic and pharmacological tools were used to manipulate endogenous EET levels. It was shown that endothelial-derived EETs play a critical role in accelerating tissue growth in vivo, including liver regeneration, kidney compensatory growth, lung compensatory growth, wound healing, corneal neovascularization, and retinal vascularization. Administration of synthetic EETs recapitulated these results, whereas lowering EET levels, either genetically or pharmacologically, delayed tissue regeneration, demonstrating that pharmacological modulation of EETs can affect normal organ and tissue growth. It was also shown that soluble epoxide hydrolase inhibitors, which elevate endogenous EET levels, promote liver and lung regeneration. Thus, our observations indicate a central role for EETs in organ and tissue regeneration and their contribution to tissue homeostasis. 2) Plasma epoxyeicosatrienoic acid (EET), dihydroxyeicosatrienoic acid (DHET), and 20-hydroxyeicosatetraenoic acid (20-HETE) levels were quantified by HPLC-MS/MS in 106 patients with stable, angiographically-confirmed CAD. Relationships between biomarkers of CYP-mediated eicosanoid metabolism and vascular function phenotypes were evaluated by Pearsons correlation.A significant inverse association was observed between 20-HETE levels (a biomarker of CYP u-hydroxylase metabolism) and brachial artery flow-mediated dilation (r = -0.255, p = 0.010). An inverse association was also observed between 14,15-EET:DHET ratios (a biomarker of sEH metabolism) and both monocyte chemoattractant protein-1 levels (r = -0.252, p = 0.009) and a consolidated cellular adhesion molecule score reflecting the levels of E-selectin and P-selectin (r = -0.216, p = 0.027). No associations with C-reactive protein or epithelial neutrophil-activating protein-78 levels were observed. Conclusions: Collectively, these findings demonstrate that enhanced CYP u-hydroxylase and sEH metabolic function are associated with more advanced endothelial dysfunction and vascular inflammation, respectively, in patients with established atherosclerotic cardiovascular disease. These findings lay the foundation for future clinical research in this area. 3) Quantitate Bisphenol A exposure from rodent bedding and diet to help assess the importance given to the estrogenic content of the animal's diet, bedding, caging, and water bottles when evaluating the estrogenic activity of bisphenol A. There is uncertainty regarding the lowest observed adverse effect levels for Bisphenol A (BPA) in mice and rats because results have been inconsistent. This study compares the unwanted estrogenic content of animal diets, bedding, cages and drinking water and its impact on determining the estrogenic activity of BPA. A mini review of the literature on BPA was conducted to determine the most frequently reported diets, bedding, cages and water bottles used in BPA studies. In low dose BPA animal studies, a high correlation existed between the use of high phytoestrogen diets, the subcutaneous route of exposure and inconsistent results. This is important because diets that contain genistein (250g/g diet) can negate the epigenetic effects of BPA (50g/g diet). Our literature review indicates that the identification and reporting of the diet, bedding, caging and water bottles used in BPA studies are not consistent. Based on these findings: We recommend that a diet containing reduced levels of phytoestrogen (<20 g/g diet) and estrogen free bedding, cages and water bottles should be used for studies evaluating the estrogenic activity of EDCs such as BPA. The oral route of BPA exposure should be used when results are to determine lowest observed adverse effects levels in humans. 4) Identify lipid/s carried by the cockroach antigen Bla g 1 in collaboration with G. Mueller (LSB) and Lars Pedersen (LSB):The structure of an rBla g 1 construct with comparable IgE and IgG reactivity to the natural allergen was solved by x-ray crystallography. The Bla g 1 repeat forms a novel fold with 6 helices. Two repeats encapsulate a large and nearly spherical hydrophobic cavity, defining the basic structural unit. Lipids in the cavity varied depending on the allergen origin. Palmitic, oleic, and stearic acids were associated with nBla g 1 from cockroach frass. One unit of Bla g 1 was equivalent to 104 ng of allergen. Conclusions: Bla g 1 has a novel fold with a capacity to bind various lipids, which suggests a digestive function associated with nonspecific transport of lipid molecules in cockroaches. Defining the basic structural unit of Bla g 1 facilitates the standardization of assays in absolute units for the assessment of environmental allergen exposure. 5) Quantitate cholestenoic acid in serum as a potential marker of severity and length of recovery of chronic lung disease. We are currently optimizing extraction and analysis conditions for tis project.
|Sayers, Brian C; Taylor, Alexia J; Glista-Baker, Ellen E et al. (2013) Role of cyclooxygenase-2 in exacerbation of allergen-induced airway remodeling by multiwalled carbon nanotubes. Am J Respir Cell Mol Biol 49:525-35|
|Panigrahy, Dipak; Kalish, Brian T; Huang, Sui et al. (2013) Epoxyeicosanoids promote organ and tissue regeneration. Proc Natl Acad Sci U S A 110:13528-33|
|Thigpen, Julius E; Setchell, Kenneth D R; Kissling, Grace E et al. (2013) The estrogenic content of rodent diets, bedding, cages, and water bottles and its effect on bisphenol a studies. J Am Assoc Lab Anim Sci 52:130-41|