Rials and ReagentsAll reagents were purchased from Sigma-Aldrich (St. Louis, Missouri, USA) or Wako (Osaka, Japan), unless otherwise stated.Sphingolipid Extraction and LC/ESI-MS AnalysisTotal lipids in WAT were extracted by Bligh and Dyer’s method [32] and analyzed using an LC/ESI-MS system composed of a quadrapole/time of flight hybrid mass spectrometer (Q-TOF micro) and an ACQUITY UPLC (Waters Corporation, Milford, Massachusetts, USA) as described previously [28,33]. MS data processing was applied using Mass++ software (http://masspp.jp/) to detect each chromatogram peak with quantitative accuracy. The arbitrary units were respectively calculated by the peak area ratio of sphingomyelin, ceramide, or GM3 molecular species to each internal standard (sphingomyelin/d18:1-12:0, ceramide/ d18:1-12:0, GM3/d18:1-14:0).Animal StudiesAll experiments were performed using F3 generation mice. Animals were housed in a SPDP web temperature-controlled room with a 12 h-light/dark cycle. Food and water were available ad libitum unless noted. Mice were fed a normal diet (CE-2; CLEA, Japan). NAC (40 mM) was postnatally administered in drinking water. All experimental protocols were approved by the Ethics Review Committee for Animal Experimentation of Kumamoto University.Metabolic MeasurementsMouse adiposity was examined by CT scanning (LaTheta; Aloka, Mitaka, Japan) as described elsewhere [29]. Plasma lipoproteins were analyzed using an HPLC system at Skylight Biotech (Akita, Japan), according to a previously described procedure [30].Immunoblot AnalysisIsolated WAT or liver was homogenized in PBS containing 1 Triton X-100 supplemented with protease inhibitors. After centrifugation at 10,0006 g for 5 min, the aqueous phase was recovered for the following immunoblot analysis. Total proteins were separated by SDS-PAGE, transferred to a nitrocellulose membrane, and analyzed using ECL Western Blotting Detection Reagents (GE Healthcare, Buckinghamshire, England) as described previously [34]. Immunoblotting was performed with antiHsc70 antibody (Santa Cruz Biotechnology, Santa Cruz, California, USA) or anti-4-hydroxy-2-nonenal (4-HNE) antibody (R D Systems, Minneapolis, Minnesota, USA). When protein carbonylation was detected, total protein was separated by SDS-PAGE and transferred to PVDF membrane. The membrane was treated with 100 methanol, and then treated with TBS buffer 
(50 mM Tris-HCl, pH 7.4, 150 mM NaCl) containing 20 methanol. After equilibration in 2 M HCl, the membrane was 15755315 incubated with 2,4-dinitrophenylhydrazone (DNPH) solution. After washing 5 times in 2 M HCl, the membrane was equilibrated in TBS buffer. The membrane was subjected to immunoblot analysis with anti2,4-dinitrophenyl (DNP) antibody (SHIMA Laboratories, Tokyo, Japan).Measurement of LPL ActivityLPL activity was measured using a Total Lipase Test kit (Progen Biotechnik, Heidelberg, Germany) as previously described [31]. Briefly, tissues were homogenized in Krebs-Ringer buffer (10 mM HEPES-KOH, pH 7.4, 120 mM NaCl, 4.7 mM KCl, 2.2 mM CaCl2, 1.2 mM KH2PO4, 1.2 mM MgSO4, 5.4 mM glucose), and heparin (Ajinomoto, Tokyo, Japan) was added to a final concentration of 100 U/ml. After 45 min-incubation at 37uC, homogenates were centrifuged, and the aqueous phase was recovered and assayed. LPL activity was 101043-37-2 normalized to total protein concentration.In Vivo Analysis of Palmitate UptakeMice were deprived of food for 4 h and injected intraperitoneally with 0.02 mmol/kg [3H]palmitic acid bound to fatty acidf.Rials and ReagentsAll reagents were purchased from Sigma-Aldrich (St. Louis, Missouri, USA) or Wako (Osaka, Japan), unless otherwise stated.Sphingolipid Extraction and LC/ESI-MS AnalysisTotal lipids in WAT were extracted by Bligh and Dyer’s method [32] and analyzed using an LC/ESI-MS system composed of a quadrapole/time of flight hybrid mass spectrometer (Q-TOF micro) and an ACQUITY UPLC (Waters Corporation, Milford, Massachusetts, USA) as described previously [28,33]. MS data processing was applied using Mass++ software (http://masspp.jp/) to detect each chromatogram peak with quantitative accuracy. The arbitrary units were respectively calculated by the peak area ratio of sphingomyelin, ceramide, or GM3 molecular species to each internal standard (sphingomyelin/d18:1-12:0, ceramide/ d18:1-12:0, GM3/d18:1-14:0).Animal StudiesAll experiments were performed using F3 generation mice. Animals were housed in a temperature-controlled room with a 12 h-light/dark cycle. Food and water were available ad libitum unless noted. Mice were fed a normal diet (CE-2; CLEA, Japan). NAC (40 mM) was postnatally administered in drinking water. All experimental protocols were approved by the Ethics Review Committee for Animal Experimentation of Kumamoto University.Metabolic MeasurementsMouse adiposity was examined by CT scanning (LaTheta; Aloka, Mitaka, Japan) as described elsewhere [29]. Plasma lipoproteins were analyzed using an HPLC system at Skylight Biotech (Akita, Japan), according to a previously described procedure [30].Immunoblot AnalysisIsolated WAT or liver was homogenized in PBS containing 1 Triton X-100 supplemented with protease inhibitors. After centrifugation at 10,0006 g for 5 min, the aqueous phase was recovered for the following immunoblot analysis. Total proteins were separated by SDS-PAGE, transferred to a nitrocellulose membrane, and analyzed using ECL Western Blotting Detection Reagents (GE Healthcare, Buckinghamshire, England) as described previously [34]. Immunoblotting was performed with antiHsc70 antibody (Santa Cruz Biotechnology, Santa Cruz, California, USA) or anti-4-hydroxy-2-nonenal (4-HNE) antibody (R D Systems, Minneapolis, Minnesota, USA). When protein carbonylation was detected, total protein was separated by SDS-PAGE and transferred to PVDF membrane. The membrane was treated with 100 methanol, and then treated with TBS buffer (50 mM Tris-HCl, pH 7.4, 150 mM NaCl) containing 20 methanol. After equilibration in 2 M HCl, the membrane was 15755315 incubated with 2,4-dinitrophenylhydrazone (DNPH) solution. After washing 5 times in 2 M HCl, the membrane was equilibrated in TBS buffer. The membrane was subjected to immunoblot analysis with anti2,4-dinitrophenyl (DNP) antibody (SHIMA Laboratories, Tokyo, Japan).Measurement of LPL ActivityLPL activity was measured using a Total Lipase Test kit (Progen Biotechnik, Heidelberg, Germany) as previously described [31]. Briefly, tissues were homogenized in Krebs-Ringer buffer (10 mM HEPES-KOH, pH 7.4, 120 mM NaCl, 4.7 mM KCl, 2.2 mM CaCl2, 1.2 mM KH2PO4, 1.2 mM MgSO4, 5.4 mM glucose), and heparin (Ajinomoto, Tokyo, Japan) was added to a final concentration of 100 U/ml. After 45 min-incubation at 37uC, homogenates were centrifuged, 
and the aqueous phase was recovered and assayed. LPL activity was normalized to total protein concentration.In Vivo Analysis of Palmitate UptakeMice were deprived of food for 4 h and injected intraperitoneally with 0.02 mmol/kg [3H]palmitic acid bound to fatty acidf.
