Mass Spectrometry Imaging Reveals Elevated Glomerular ATP/AMP in Diabetes/obesity and Identifies Sphingomyelin as a Possible Mediator.
AMP-activated protein kinase (AMPK) is suppressed in diabetes and may be due to a high ATP/AMP ratio, however the quantitation of nucleotides in vivo has been extremely difficult. Via matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) to localize renal nucleotides we found that the diabetic kidney had a significant increase in glomerular ATP/AMP ratio. Untargeted MALDI-MSI analysis revealed that a specific sphingomyelin species (SM(d18:1/16:0)) accumulated in the glomeruli of diabetic and high-fat diet-fed mice compared with wild-type controls. In vitro studies in mesangial cells revealed that exogenous addition of SM(d18:1/16:0) significantly elevated ATP via increased glucose consumption and lactate production with a consequent reduction of AMPK and PGC1α. Furthermore, inhibition of sphingomyelin synthases reversed these effects. Our findings suggest that AMPK is reduced in the diabetic kidney due to an increase in the ATP/AMP ratio and that SM(d18:1/16:0) could be responsible for the enhanced ATP production via activation of the glycolytic pathway.
Institute of Metabolomic Medicine, University of California San Diego, La Jolla, CA 92093, USA; Center for Renal Translational Medicine, Division of Nephrology-Hypertension, University of California San Diego, La Jolla, CA 92093, USA; Division of Nephrology-Hypertension, Veterans Affairs San Diego Healthcare System, La Jolla, CA 92093, USA; Department of Nephrology, Rheumatology, Endocrinology and Metabolism, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan.
Satoshi
S
Miyamoto
Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093, USA; Department of Chemistry, National Taiwan University, Taipei 106, Taiwan.
Cheng-Chih
CC
Hsu
ImaBiotech, MS Imaging Department, Lille 59120, France.
Gregory
G
Hamm
Institute of Metabolomic Medicine, University of California San Diego, La Jolla, CA 92093, USA; Center for Renal Translational Medicine, Division of Nephrology-Hypertension, University of California San Diego, La Jolla, CA 92093, USA.
Manjula
M
Darshi
Institute of Metabolomic Medicine, University of California San Diego, La Jolla, CA 92093, USA; Center for Renal Translational Medicine, Division of Nephrology-Hypertension, University of California San Diego, La Jolla, CA 92093, USA; Division of Nephrology-Hypertension, Veterans Affairs San Diego Healthcare System, La Jolla, CA 92093, USA.
Maggie
M
Diamond-Stanic
Center for Renal Translational Medicine, Division of Nephrology-Hypertension, University of California San Diego, La Jolla, CA 92093, USA.
Anne-Emilie
AE
Declèves
Institute of Metabolomic Medicine, University of California San Diego, La Jolla, CA 92093, USA; Center for Renal Translational Medicine, Division of Nephrology-Hypertension, University of California San Diego, La Jolla, CA 92093, USA; Division of Nephrology-Hypertension, Veterans Affairs San Diego Healthcare System, La Jolla, CA 92093, USA.
Larkin
L
Slater
Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA.
Subramaniam
S
Pennathur
ImaBiotech, MS Imaging Department, Lille 59120, France.
Jonathan
J
Stauber
Institute of Metabolomic Medicine, University of California San Diego, La Jolla, CA 92093, USA; Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093, USA; Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093, USA.
Pieter C
PC
Dorrestein
Institute of Metabolomic Medicine, University of California San Diego, La Jolla, CA 92093, USA; Center for Renal Translational Medicine, Division of Nephrology-Hypertension, University of California San Diego, La Jolla, CA 92093, USA; Division of Nephrology-Hypertension, Veterans Affairs San Diego Healthcare System, La Jolla, CA 92093, USA. Electronic address: kumarsharma@ucsd.edu.
Kumar
K
Sharma
D055372:AMP-Activated Protein Kinases / Q000378:metabolism; D000249:Adenosine Monophosphate / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D002460:Cell Line; D003920:Diabetes Mellitus / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D006801:Humans; D007678:Kidney Glomerulus / Q000737:chemistry* / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism; D050527:Mesangial Cells / Q000737:chemistry / Q000166:cytology / Q000187:drug effects; D051379:Mice; D009765:Obesity / Q000378:metabolism*; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods; D013109:Sphingomyelins / Q000378:metabolism* / Q000494:pharmacology
D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D013109:Sphingomyelins; D019344:Lactic Acid; D000249:Adenosine Monophosphate; D000255:Adenosine Triphosphate; D055372:AMP-Activated Protein Kinases; D005947:Glucose
AMPK; ATP; Chronic kidney disease; Glycolysis; Matrix-assisted laser desorption/ionization mass spectrometry imaging; Sphingomyelin