TitleCharacteristics of the rat cardiac sphingolipid pool in two mitochondrial subpopulations.
Publication TypeJournal Article
Year of Publication2010
AuthorsMonette JS, Gómez LA, Moreau RF, Bemer BA, Taylor AW, Hagen TM
JournalBiochem Biophys Res Commun
Date Published2010 Jul 23
KeywordsAnimals, Male, Mitochondria, Heart, Rats, Rats, Inbred F344, Sarcolemma, Sphingolipids

Mitochondrial sphingolipids play a diverse role in normal cardiac function and diseases, yet a precise quantification of cardiac mitochondrial sphingolipids has never been performed. Therefore, rat heart interfibrillary mitochondria (IFM) and subsarcolemmal mitochondria (SSM) were isolated, lipids extracted, and sphingolipids quantified by LC-tandem mass spectrometry. Results showed that sphingomyelin (approximately 10,000 pmol/mg protein) was the predominant sphingolipid regardless of mitochondrial subpopulation, and measurable amounts of ceramide (approximately 70 pmol/mg protein) sphingosine, and sphinganine were also found in IFM and SSM. Both mitochondrial populations contained similar quantities of sphingolipids except for ceramide which was much higher in SSM. Analysis of sphingolipid isoforms revealed ten different sphingomyelins and six ceramides that differed from 16- to 24-carbon units in their acyl side chains. Sub-fractionation experiments further showed that sphingolipids are a constituent part of the inner mitochondrial membrane. Furthermore, inner membrane ceramide levels were 32% lower versus whole mitochondria (45 pmol/mg protein). Three ceramide isotypes (C20-, C22-, and C24-ceramide) accounted for the lower amounts. The concentrations of the ceramides present in the inner membranes of SSM and IFM differed greatly. Overall, mitochondrial sphingolipid content reflected levels seen in cardiac tissue, but the specific ceramide distribution distinguished IFM and SSM from each other.

Alternate JournalBiochem. Biophys. Res. Commun.
PubMed ID20599536
PubMed Central IDPMC2939858
Grant ListR01 AG017141 / AG / NIA NIH HHS / United States
R01 AG017141-02 / AG / NIA NIH HHS / United States
2R01AG017141 / AG / NIA NIH HHS / United States
ES00240 / ES / NIEHS NIH HHS / United States