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Vitamin D and Eicosanoids

Oxylipins

The laboratory of Dr. Bruce Hammock will offer advanced metabolomics services and development in the area of oxylipins.

The lab was among the first to develop standardized and validatedmass spectrometry assays for oxylipins. Oxylipins are a group of oxidized metabolites ofpolyunsaturated fatty acids, and play important roles in many physiological processes, such as cell proliferation,apoptosis, tissue repair, blood clotting, blood vessel permeability, inflammation and immune cell behavior.

Assessment of oxidized fatty acid levels is important for understanding their homeostatic and physiologicalroles under regulation of cyclooxygenase (COX), lipoxygenase (LOX), and cytochrome P450 (CYP) enzymes. Because there is cross talk among oxylipins as well as cross talk among oxylipins andchemokines, cytokines and other chemical mediators, it is vital to use comprehensive profiling for oxylipins. Wedeveloped solid phase extraction-liquid chromatography-electrospray ionization MS/MS (SPE-LC-ESI MS/MS) methods to monitor these important metabolites covering102 oxylipins for up to 1,000 samples per year tobe available in the Advanced Services Core, for example in pilot and feasibility studies.

oxylipins

profiling regulatory lipid mediators derived from variety of PUFAs anding UPLC-MS/MS

 

We propose to advance the use of oxylipin metabolic profiling in several ways:

  1. We will enlarge the active target lists for oxylipin metabolite profiling, including, for example, for inclusion of cysteinyl peptides such as the slow relaxing substance of anaphylaxis LTD4 and related compounds associated with asthma, as well as lipid amides including endocannibanoids. We will further add bioactive oxylipin formed from omega-3 lipids. This becomes increasingly important as omega-3 lipids are added to our diet as value added materials. From an environmental perspective, the arachidonate cascade is a biological monitor of health and thus may yield useful biomarkers for altered health. These platforms will be used to probe questions of the interaction between nutrition and environmental exposures.
  2. We will reduce the sample volume using nano LC/MS system. With nanoLC, we can reduce the injection sample volume from the current 10 μL to around 20-60 nL, and therefore reduce the use of biological fluids or tissues, which will serve as bridge to ‘image-guided metabolomics’.
  3. We will improve the sensitivity using derivatization methods. For example, a one-step extraction and derivatization method has been proposed, essentially based on a dispersive liquid-liquid microextraction. We will try different derivatization agents to derivatize certain oxylipins with low sensitivity, and to decrease the limit of detection.
  4. The Hammock laboratory will work together with the Gaikwad and Newman laboratories to improve data processing strategies, including in-filling of missing values.
  5. We will develop other platforms related to the interaction of nutrition and environmental health.

 

Equipment

Mass Spectrometry: Eight instruments are available including three electrospray triple quadrapole LC-MSsystems (Waters Aquity UPLC/Waters Xevo TQ-S, Shimadzu AP10/Micromass Quattro Ultima, WatersUPLC/Waters Quattro Premier), a linear ion trap LC-MS (Agilent HP1200/ABI QTRAP4000), an electrosprayTOF LC-MS (Waters 2795 HPLC/Micromass LCT TOF high resolution MS), an electrospray Q-TOF LC-MS(Agilent HP1200 and Agilent 1200 NanoLC /ABI QSTAR XL high resolution MS), two benchtop GLC-MS(HP6890/HP5973 MSD equipped with a purge and trap (Tekmar 3000) for volatile analysis, Agilent7890/5975 MSD) and a Finnigan GCQ GC-MS with ion trap analyzer capable of MS/MS and chemicalionization.

 

Nuclear Magnetic Resonance Spectrometry Resources: We enjoy access to NMR spectrometers availablethrough the campus shared-use NMR Facility. There are a total of 10 spectrometers of varying purposes andcapabilities available. Four instruments (2 Mercury-300 MHz, 1 Inova-400 MHz, 1 VNMRS-600 MHz) arelargely devoted to structural characterization of organic and inorganic molecules. Two additional instruments(Avance 500 MHz and Avance 600 MHz) are available for solution studies of biomolecules. All thespectrometers are multinuclear and a large variety of solvents are available for use.

 

Staff

Bruce D. Hammock    bdhammock@ucdavis.edu (530)752-8465

Postdoctoral scholar for Pilot & Feasibility studies: Niu Jun, PhD

Jun Yang                   junyang@ucdavis.edu (530)752-5109

Hua Dong                 hdong@ucdavis.edu            (530) 752-5109

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