Lipid Imaging Mass Spectrometry.

Transcription

1 Lipid Imaging Mass Spectrometry. NH 2 P H H H H P H H P H N N Advanced Graduate Course in Metabolomics Janusz Kabarowski, Dept. of Microbiology, UAB. Matrix-Assisted Laser Desorption/Ionization (MALDI): Matrix molecules absorb laser light, enter an excited state, and collide with sample molecules, facilitating charge transfer to create ions. Conventional MALDI plate MALDI-TF instrument Mass Spectrometric Imaging for biomedical tissue analysis Kamila Chughtai and Ron M.A. Heeren Chem Rev. Vol.110(5): pp , 2010.

2 Cryosectioning onto Indium Tin xide (IT) coated glass slides and scanning digital image of slide for teaching FlexControl software on MALDI-TF. Vacuum sublimation is used to apply an even microscopically thin uniform layer of matrix compound onto tissue section without the need for solvents. Sublimation: the transition of a substance from solid to gas phase without an intermediate liquid phase. MALDI matrices for lipid imaging: DHB: 2,5-dihydrobenzoic acid (+ve mode) 1,5-diaminonapthalene (-ve mode)

3 How do we apply matrix for MALDI Imaging? We built a vacuum sublimation apparatus. Digital vacuum monitor Vacuum micro-valves Pirani vacuum gauge Vacuum sublimation chamber vacuum exhaust Heated sand bath Vacuum at 0.05 Torr pressure is required in sublimation chamber and is monitored by electronic Pirani vacuum gauge. 750 Torr (atmospheric pressure) 0.05 Torr

4 Matrix deposition by vacuum sublimation C Cold condensor unit of vacuum sublimation chamber 0.05 Torr IT (indium-tin-oxide coated) slide with cryosections Matrix compound 140 C Heated sand Slides with matrix applied by vacuum sublimation. Deposition of the matrix compound is at the molecular level because gaseous molecules recrystallize at the relatively cold surface of the tissue section attached to the cold condenser. The uniformity of matrix deposition onto the slide attached to the cold condenser surface reflects the random Brownian motion of the released gaseous matrix molecules.

5 Adaptated MALDI plate holds slides for MALDIimaging Mass Spectrometry. Conventional MALDI plate MALDI plate for cryosections Setting up a MALDI-IMS run after matrix sublimation. (1) The slide is placed into a Bruker slide adaptor and into the MALDI-TF instrument (2) Regions to image are selected from the scanned photo of the slide

6 MALDI-IMS in action. MALDI-IMS in action.

7 How are we applying MALDI-IMS to our research? Lipid based mechanisms of immune suppression and antiinflammatory action by HDL in Lupus. Acute kidney injury (UAB/UCSD Brien Center). Lipids as mediators of age-related changes in eye lens. Zebrafish - an emerging model in biomedical research.. $0.39/tank/day (max fish per tank) embryos weekly per sexually mature female Functional vision by 5 days of age Transparent embryos permeable to small molecules Various mutants model human ocular disorders $0.75/cage/day (max 4-5 mice per cage) 6-8 pups monthly per sexually mature female Functional vision by 2 weeks of age Stephen Watts, Ph.D., Department of Biology, Director UAB Aquatic Animal Research Core for NRC.

8 Age associated changes in the lens lipidome of Mouse and Zebrafish. 2 month-old Zebrafish 12 month-old Zebrafish 300 M 300 M AGING 1 month-old Mouse 12 month-old Mouse AGING 300 M 300 M Specific aims of the study: 1) To characterize and compare the lens lipidomes of Mice and Zebrafish. 2) To analyze the changes that occur in the lens lipdome with aging. 3) To determine where lipid changes are occurring in the lens. 8 weeks 12 months 2 weeks 12 months 6 x 12 lenses 6 x 5 lenses 6 x 3 lenses 6 x 1 lens Normalized weight Analyzed using ESI-MS/MS on Triple-TF Mass Spectrometer Stephen Barnes, Ph.D., Department of Pharmacology & Toxicology, Director UAB TMPL.

9 ESI-MS/MS on Triple-TF Mass Spectrometer. Complete and Comprehensive Data Collection TF MS Scanning Storing all Product Ions Lipidomic Profiling Map of Rat Brain Extracts Acquired in Negative Mode signal intensity Fragment mass m/z Q1 selection window amu Precursor mass m/z Mouse lens positive mode (Total lipids). 6 -log 10 p p 0.05 (-log 10 p>1.301) Log 2 FC PG -44:2 (-PG) SM 38:4;2 (SM) LPE 12:3 (LPE p ) LPC 16:0 PC 36:4 (16:0/20:4) PC -32:1 (PC) [alkyl link] PE 36:0 (-PE) SM 24:1;2 (SM) SM 32:3;4 (SM) SM 34:0;4 (SM) SM 34:1;3 (LCB 18:2, 2-2H2, LCB 18:1;3-3H2) LMMPE 18:0 (-MMPE) MM(monomethyl) PE 36:0 (-MMPE)

10 Zebrafish lens positive mode (Total lipids). 12 -log 10 p p 0.05 (-log 10 p>1.301) Log 2 FC PG -44:2 (-PG) SM 38:4;2 (SM) LPE 12:3 (LPE p ) LPC 16:0 PC 36:4 (16:0/20:4) PC -32:1 (PC) [alkyl link] PE 36:0 (-PE) SM 24:1;2 (SM) SM 32:3;4 (SM) SM 34:0;4 (SM) SM 34:1;3 (LCB 18:2, 2-2H2, LCB 18:1;3-3H2) LMMPE 18:0 (-MMPE) MM(monomethyl) PE 36:0 (-MMPE) Sphingomyelins are increased with ageing in mouse (Black) and Zebrafish (white) lens. SM 31:2;4 SM 33:2;4 SM 30:2;4 -Log 10 p Mouse Zebrafish SM 34:0;4 SM 38:4;2 SM 32:3;4 SM 34:1;3 SM 24:4;3 P NH H N 8 6 SM 34:1;3 (LCB 18:2;2-2H2, LCB 18:1;3-3H2) 4 p 0.05 (-log 10 p>1.301) Log 2 FC

11 Mouse lens Phosphatidylcholines (white) and Lysophosphatidylcholines (black). H P H H H P H p 0.05 (-log 10 p>1.301) N 36:6 PC -Log 10 p :3 LPC ND 22:3 LPC ND 30:2 PC ND -linked acyl PCs only detected in Mouse 1-alkyl, 2-acyl PC CH H 3 N CH P 3 H :1 PC N (125m/z MSMS) :1 PC :4 PC 16:0 LPC -40:2 PC 42:2 PC :3 PC 14:0 LPC 34:5 PC -32:1 PC 30:1 PC 16:0 LPC (125m/z MSMS) Log 2 FC Zebrafish lens Phosphatidylcholines (white) and Lysophosphatidylcholines (black). H P H H H P H N N 42:3 PC 42:2 PC 42:1 PC -Log 10 p No alkyl (-) PCs detected in Zebrafish 36:4 PC 30:1 PC 20:3 LPC 1-alkyl, 2-acyl PC CH H 3 N CH P 3 H 14:0 LPC 34:5 PC 36:6 PC 22:3 LPC 16:0 LPC 30:2 PC 3 p 0.05 (-log 10 p>1.301) Log 2 FC

12 ESI-MS/MS fragments from m/z 36:4 PC (+mode) phosphocholine head group H P H N Intensity log 10 p p Log 2 FC Mass/Charge, Da Precursor: Da, CE: 50.0 Spectrum from MSMSALL_Pos F2.wiff (sample 1) - Pos F-2, Experiment 2, +TF MS^2 ( ) from min 1150 ESI-MS/MS fragments from m/z 36:4 PC acetate adduct (-mode) Intensity FA 20: FA 16: H P H N Mass/Charge, Da Precursor: Da Spectrum from MSMSALL_Neg F2.wiff (sample 1) - Neg F-2, Experiment 2, -TF MS^2 ( ) from min

13 So where in the lens are these changes in 16:0/20:4 PC occuring? A 300 M B 300 M 10% gelatin/cryosection H&E Formalin/paraffin H&E Tissue processing for matrix application and eye lens MALDI-IMS is challenging Formalin fixed paraffin sections of lens (B) cannot be used for MALDI-IMS (although certain modifications of fixation protocols might allow for subsequent lipid MALDI-IMS). Cryosectioning (after tissue embedding in 10% gelatin) must therefore be optimized for the tissue being studied. In the case of lens, this is very challenging as the dense lens material has a propensity to crack (A). Positive ion mode MALDI average mass spectra of (A) 8 week old and (B) 12 month old Zebrafish eyes, showing the location of the peaks for which images were subsequently taken. A 8 week old Zebrafish H + Na + K + B 12 month old Zebrafish H + Na + K + Peaks correspond to expected protonated, sodiated, and potassiated adducts of PC(36:4).

14 MALDI-IMS on protonated, sodiated, and potassiated adducts of PC(36:4) in zebrafish eye. [PC(36:4)+H] + = [PC(36:4)+Na] + = [PC(36:4)+K] + = months old 8 weeks old MS/MS on protonated adduct of PC(36:4) in Zebrafish eye choline head group H P H N parent ion weeks old ZF m/z MS/MS on m/z shows fragmentation indicative of PC(16:0/20:4) months old ZF Mass/Charge, Da Mass/Charge 800 (m/z), Da

15 MALDI-IMS on 16:0/20:4 PC(36:4) in mouse eye. 16:0/20:4 PC LD MUSE LENS #2 ( ) 16:0/20:4 PC 1 year old MUSE LENS #2 ( )

16 Restricted diacyl phospholipids in lens core. TTAL EYE spectrum Mouse eye, LENS PERIPHERY spectrum LENS PERIPHERY spectrum LENS CRE spectrum

17 Quantitative and Spatial Analysis of Lipids Involved in Acute Kidney Injury. Specific aims of the study: 1) To characterize the kidney lipidome of mice following acute injury (quantitatively) weeks old C57Bl6/J Sham IR Normalized kidney weight Analyzed using ESI-MS/MS on 5600 Triple-TF Mass Spectrometer

18 ESI-MS/MS on Triple-TF Mass Spectrometer. MS/MS of Every Precursor Product Ion Scan of Every Lipid Lipidomic Profiling Map of Rat Brain Acquired in Negative Mode storing all product ion spectra; 1.6 min Fragment mass m/z signal intensity Precursor mass m/z Specific aims of the study: 2) To analyze WHERE the changes in lipids occur in the kidney (spatially) and to characterize those lipids that remain unchanged quantitatively but might be spatially altered weeks old C57Bl6/J Sham IR Kidney cryosections MALDI-Imaging MS on a Bruker-TF Mass Spectrometer

19 In vivo mouse model of AKI: nephrectomy SWATH 5600 TF Resuspend lipids in MetH Dried lipids under Argon Sham or IR left kidney Extract lipids (Bligh Dyer) ½ Kidney homogenization in 1ml PBS/BHT Kidney homogenization in 1ml PBS/BHT Samples under Argon -80 C 30 mins renal ligation 6 hours reperfusion Euthanization PBS/BHT perfusion ½ Kidney 10% gelatin embedding MALDI-IMS Plasma creatinine (mg/dl) SHAM control IR (0.5/6 hrs) IR (0.5/24hrs) plasma creatinine 1-2mg/dL Mouse kidney lipids changed following IR (0.5/6hrs) 3.0 (5600 Triple-TF SWATH PE -40:5 positive mode) _639.6 GT2 26:0;2 (LCB 18:0;2-H 2 0) 900.8_284.3 p 0.05 (-log 10 p>1.301) -log 10 p GD2 32:2;2 (LCB 18:2;2-H 2 0, LCB 18:1;3-3H 2 ) 900.8_ PC -38: _184.1 PE -40: _641.6 PE -42: _198.1 CE 27:3 +NH 4 (chol) 790.7_369.4 LPC 22: _184.1 SM 39:3; _ weeks old C57Bl6/J (n=6) Log 2 FC

20 Mouse kidney lipids changed following IR (0.5/6hrs) (5600 Triple-TF SWATH negative mode). PC 16:0/18: _ log 10 p PE -40: _196.0 LPI -28: _223.0 PE 46: _196.0 PE 14:0/20: _227.2 PE -14:0/20: _303.2 PE 46: _ p 0.05 (-log 10 p>1.301) Log 2 FC 8-10 weeks old C57Bl6/J (n=6) 1-alkyl, 2-acyl PE 1-acyl, 2-acyl PE H P H NH 2 H P H NH 2 PE -40:4 intensity r=0.771 p= PE -40:5 intensity r=0.724 p= Plasma creatinine (IR 0.5/6hrs) Plasma creatinine (IR 0.5/6hrs)

21 1-alkyl, 2-acyl PC 1-acyl, 2-acyl PC H P H N H P H N PC -38:1 intensity r=0.730 p= SM -39:3;2 intensity r= p= Plasma creatinine (IR 0.5/6hrs) Plasma creatinine (IR 0.5/6hrs) CE 27:3 +NH 4 (chol) intensity r=0.886 p= Plasma creatinine (IR 0.5/6hrs) GD2 32:2;2 intensity r= p= Plasma creatinine (IR 0.5/6hrs)

22 SHAM control IR (0.5/6hrs) MALDI-IMS on PE -40:4 (782.6_641.6) -log 10 p PE -40: _639.6 p 0.05 (-log 10 p>1.301) PE -40: _641.6 SHAM Log 2 FC IR

23 Acknowledgments. Stephen Barnes Landon Wilson Ray Moore UAB, Targeted Metabolomics and Proteomics Lab David Graves UAB, Chair Department of Chemistry Anupam Agarwal UAB, Dept Medicine, Brien Acute Kidney Injury Research Center Trenton Schoeb UAB, Dept Genetics, Dir. Comparative Pathology Core Laboratory Miranda Collier UAB, Honors and Chemistry Scholars Undergraduate Fellowship Program (Currently Ph.D University of xford) Alex Johnson Kelly Walters UAB, Undergraduate Chemistry (Pre-Med) Sangeetha Rao UAB Resident Steve Burgess Dir. R&D, Avantipolar Lipids