Imaging Mass Spectrometry Reveals Acyl-Chain- and Region-Specific Sphingolipid Metabolism in the Kidneys of Sphingomyelin Synthase 2-Deficient Mice

PLoS One. 2016 Mar 24;11(3):e0152191. doi: 10.1371/journal.pone.0152191. eCollection 2016.

Abstract

Obesity was reported to cause kidney injury by excessive accumulation of sphingolipids such as sphingomyelin and ceramide. Sphingomyelin synthase 2 (SMS2) is an important enzyme for hepatic sphingolipid homeostasis and its dysfunction is considered to result in fatty liver disease. The expression of SMS2 is also high in the kidneys. However, the contribution of SMS2 on renal sphingolipid metabolism remains unclear. Imaging mass spectrometry is a powerful tool to visualize the distribution and provide quantitative data on lipids in tissue sections. Thus, in this study, we analyzed the effects of SMS2 deficiency on the distribution and concentration of sphingomyelins in the liver and kidneys of mice fed with a normal-diet or a high-fat-diet using imaging mass spectrometry and liquid chromatography/electrospray ionization-tandem mass spectrometry. Our study revealed that high-fat-diet increased C18-C22 sphingomyelins, but decreased C24-sphingomyelins, in the liver and kidneys of wild-type mice. By contrast, SMS2 deficiency decreased C18-C24 sphingomyelins in the liver. Although a similar trend was observed in the whole-kidneys, the effects were minor. Interestingly, imaging mass spectrometry revealed that sphingomyelin localization was specific to each acyl-chain length in the kidneys. Further, SMS2 deficiency mainly decreased C22-sphingomyelin in the renal medulla and C24-sphingomyelins in the renal cortex. Thus, imaging mass spectrometry can provide visual assessment of the contribution of SMS2 on acyl-chain- and region-specific sphingomyelin metabolism in the kidneys.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Ceramides / metabolism
  • Diet, High-Fat
  • Humans
  • Kidney / injuries
  • Kidney / metabolism*
  • Kidney / pathology
  • Liver / injuries
  • Liver / metabolism
  • Mass Spectrometry
  • Mice
  • Mice, Knockout
  • Obesity / metabolism*
  • Obesity / pathology
  • Sphingolipids / metabolism*
  • Sphingomyelins / metabolism
  • Transferases (Other Substituted Phosphate Groups) / deficiency
  • Transferases (Other Substituted Phosphate Groups) / genetics
  • Transferases (Other Substituted Phosphate Groups) / metabolism*

Substances

  • Ceramides
  • Sphingolipids
  • Sphingomyelins
  • Transferases (Other Substituted Phosphate Groups)
  • Sgms2 protein, mouse

Grants and funding

This study was supported by the Creation of Innovation Centers for Advanced Interdisciplinary Research Areas Program, Ministry of Education, Culture, Sports, Science and Technology, Japan (URL: http://www.jst.go.jp/shincho/sentanyugo/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. This study was also funded by Shionogi & Co., Ltd. (http://www.shionogi.co.jp/index.html). The funder provided support in the form of salaries for authors [MS MW TY KH YN TO], but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the 'author contributions' section.