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Yoshimi Miki,
Kei Yamamoto,
Yoshitaka Taketomi,
Hiroyasu Sato,
Kanako Shimo,
Tetsuyuki Kobayashi,
Yukio Ishikawa,
Toshiharu Ishii, Hiroki Nakanishi,
Kazutaka Ikeda,
Ryo Taguchi,
Kenji Kabashima,
Makoto Arita,
Hiroyuki Arai,
Gérard Lambeau,
James M Bollinger,
Shuntaro Hara,
Michael H Gelb,
Makoto Murakami
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ABSTRACT: Resolution of inflammation is an active process that is mediated in part by antiinflammatory lipid mediators. Although phospholipase A2 (PLA2) enzymes have been implicated in the promotion of inflammation through mobilizing lipid mediators, the molecular entity of PLA2 subtypes acting upstream of antiinflammatory lipid mediators remains unknown. Herein, we show that secreted PLA2 group IID (PLA2G2D) is preferentially expressed in CD11c(+) dendritic cells (DCs) and macrophages and displays a pro-resolving function. In hapten-induced contact dermatitis, resolution, not propagation, of inflammation was compromised in skin and LNs of PLA2G2D-deficient mice (Pla2g2d(-/-)), in which the immune balance was shifted toward a proinflammatory state over an antiinflammatory state. Bone marrow-derived DCs from Pla2g2d(-/-) mice were hyperactivated and elicited skin inflammation after intravenous transfer into mice. Lipidomics analysis revealed that PLA2G2D in the LNs contributed to mobilization of a pool of polyunsaturated fatty acids that could serve as precursors for antiinflammatory/pro-resolving lipid mediators such as resolvin D1 and 15-deoxy-Δ(12,14)-prostaglandin J2, which reduced Th1 cytokine production and surface MHC class II expression in LN cells or DCs. Altogether, our results highlight PLA2G2D as a "resolving sPLA2" that ameliorates inflammation through mobilizing pro-resolving lipid mediators and points to a potential use of this enzyme for treatment of inflammatory disorders.
Journal of Experimental Medicine 05/2013; · 13.85 Impact Factor
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Yoko Tajima,
Masaki Ishikawa,
Keiko Maekawa,
Mayumi Murayama,
Yuya Senoo,
Tomoko Nishimaki-Mogami, Hiroki Nakanishi,
Kazutaka Ikeda,
Makoto Arita,
Ryo Taguchi,
Alato Okuno,
Ryuta Mikawa,
Shumpei Niida,
Osamu Takikawa,
Yoshiro Saito
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ABSTRACT: BACKGROUND: Alzheimer's disease (AD), the most common cause of dementia among neurodegenerative diseases, afflicts millions of elderly people worldwide. In addition to amyloid-beta (Abeta) peptide and phosphorylated tau, lipid dysregulation is suggested to participate in AD pathogenesis. However, alterations in individual lipid species and their role in AD disease progression remain unclear. METHODS: We performed a lipidomic analysis using brain tissues and plasma obtained from mice expressing mutated human amyloid precursor protein (APP) and tau protein (Tg2576xJNPL3) (APP/tau mice) at 4 (pre-symptomatic phase), 10 (early symptomatic) and 15 months (late symptomatic). RESULTS: Levels of docosahexaenoyl (22:6) cholesterol ester (ChE) were markedly increased in APP/tau mice compared to controls at all stages examined. Several species of ethanolamine plasmalogens (pPEs) and sphingomyelins (SMs) showed different levels between brains from APP/tau and control mice at various stages of AD. Increased levels of 12-hydroxyeicosatetraenoic acid (12-HETE) during the early symptomatic phase were consistent with previous reports using human AD brain tissue. In addition, 19,20-dihydroxy-docosapentaenoic acid (19,20-diHDoPE) and 17,18-dihydroxy-eicosatetraenoic acid (17,18-diHETE), which are produced from docosahexaenoic acid and eicosapentaenoic acid via 19,20-epoxy-docosapentaenoic acid (19,20-EpDPE) and 17,18-epoxy-eicosatetraenoic acid (17,18-EpETE), respectively, were significantly increased in APP/tau brains during the pre-symptomatic phase, and concomitant increases occurred in plasma. Several arachidonic acid metabolites such as prostaglandin D2 (PGD2) and 15-hydroxyeicosatetraenoic acid (15-HETE), which have potential deteriorating and protective actions, respectively, were decreased in the early symptomatic phase of APP/tau mice. Significant decreases in phosphatidylcholines and PEs with polyunsaturated fatty acids were also detected in the late symptomatic phase, indicating a perturbation of membrane properties. CONCLUSION: Our results provide fundamental information on lipid dysregulation during various stages of human AD.
Lipids in Health and Disease 05/2013; 12(1):68. · 2.17 Impact Factor
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Keiko Maekawa,
Akiyoshi Hirayama,
Yuko Iwata,
Yoko Tajima,
Tomoko Nishimaki-Mogami,
Shoko Sugawara,
Noriko Ueno,
Hiroshi Abe,
Masaki Ishikawa,
Mayumi Murayama,
Yumiko Matsuzawa, Hiroki Nakanishi,
Kazutaka Ikeda,
Makoto Arita,
Ryo Taguchi,
Naoto Minamino,
Shigeo Wakabayashi,
Tomoyoshi Soga,
Yoshiro Saito
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ABSTRACT: Dilated cardiomyopathy (DCM), a common cause of heart failure, is characterized by cardiac dilation and reduced left ventricular ejection fraction, but the underlying mechanisms remain unclear. To investigate the mechanistic basis, we performed global metabolomic analysis of myocardial tissues from the left ventricles of J2N-k cardiomyopathic hamsters. This model exhibits symptoms similar to those of human DCM, owing to the deletion of the δ-sarcoglycan gene. Charged and lipid metabolites were measured by capillary electrophoresis mass spectrometry (MS) and liquid chromatography MS(/MS), respectively, and J2N-k hamsters were compared with J2N-n healthy controls at 4 (presymptomatic phase) and 16weeks (symptomatic) of age. Disturbances in membrane phospholipid homeostasis were initiated during the presymptomatic phase. Significantly different levels of charged metabolites, occurring mainly in the symptomatic phase, were mapped to primary metabolic pathways. Reduced levels of metabolites in glycolysis, the pentose phosphate pathway, and the tricarboxylic acid cycle, together with large decreases in major triacylglycerol levels, suggested that decreased energy production leads to cardiac contractile dysfunction in the symptomatic phase. A mild reduction in glutathione and a compensatory increase in ophthalmate levels suggest increased oxidative stress in diseased tissues, which was confirmed by histochemical staining. Increased levels of 4 eicosanoids, including prostaglandin (PG) E2 and 6-keto-PGF1α, in the symptomatic phase suggested activation of the protective response pathways. These results provide mechanistic insights into DCM pathogenesis and may help identify new targets for therapeutic intervention and diagnosis.
Journal of Molecular and Cellular Cardiology 02/2013; · 5.17 Impact Factor
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Nagisa Arimitsu,
Takeshi Kogure,
Takashi Baba,
Kazuki Nakao,
Hiroshi Hamamoto,
Kazuhisa Sekimizu,
Akitsugu Yamamoto, Hiroki Nakanishi,
Ryo Taguchi,
Mitsuo Tagaya,
Katsuko Tani
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ABSTRACT: p125/Sec23ip is a phospholipase A(1)-like protein that interacts with Sec23, a coat component of COPII vesicles that bud from endoplasmic reticulum exit sites. To understand its physiological function, we produced p125 knockout mice. The p125 knockout mice grew normally, but males were subfertile. Sperm from p125-deficient mice had round heads and lacked the acrosome, an organelle containing the enzymes responsible for fertilization. p125 was found to be expressed at stages I-XII of spermatogenesis, similar to the expression pattern of proteins involved in acrosome biogenesis. These results suggest that p125 plays an important role in spermiogenesis.
FEBS letters 05/2011; 585(14):2171-6. · 3.54 Impact Factor
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ABSTRACT: Salamander large cells facilitated identification and localization of lipids by MALDI imaging mass spectrometry. Salamander retina lipid extract showed similarity with rodent retina lipid extract in phospholipid content and composition. Like rodent retina section, distinct layer distributions of phospholipids were observed in the salamander retina section. Phosphatidylcholines (PCs) composing saturated and monounsaturated fatty acids (PC 32:0, PC 32:1, and PC 34:1) were detected mainly in the outer and inner plexiform layers (OPL and IPL), whereas PCs containing polyunsaturated fatty acids (PC 36:4, PC 38:6, and PC 40:6) composed the inner segment (IS) and outer segment (OS). The presence of PCs containing polyunsaturated fatty acids in the OS layer implied that these phospholipids form flexible lipid bilayers, which facilitate phototransduction process occurring in the rhodopsin rich OS layer. Distinct distributions and relative signal intensities of phospholipids also indicated their relative abundance in a particular cell or a cell part. Using salamander large cells, a single cell level localization and identification of biomolecules could be achieved by MALDI imaging mass spectrometry.
The Journal of Lipid Research 03/2011; 52(3):463-70. · 5.56 Impact Factor
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Kei Yamamoto,
Yoshitaka Taketomi,
Yuki Isogai,
Yoshimi Miki,
Hiroyasu Sato,
Seiko Masuda,
Yasumasa Nishito,
Kiyokazu Morioka,
Yoshikazu Ishimoto,
Noriko Suzuki,
Yasunori Yokota,
Kohji Hanasaki,
Yukio Ishikawa,
Toshiharu Ishii,
Tetsuyuki Kobayashi,
Kiyoko Fukami,
Kazutaka Ikeda, Hiroki Nakanishi,
Ryo Taguchi,
Makoto Murakami
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ABSTRACT: Although perturbed lipid metabolism can often lead to skin abnormality, the role of phospholipase A(2) (PLA(2)) in skin homeostasis is poorly understood. In the present study we found that group X-secreted PLA(2) (sPLA(2)-X) was expressed in the outermost epithelium of hair follicles in synchrony with the anagen phase of hair cycling. Transgenic mice overexpressing sPLA(2)-X (PLA2G10-Tg) displayed alopecia, which was accompanied by hair follicle distortion with reduced expression of genes related to hair development, during a postnatal hair cycle. Additionally, the epidermis and sebaceous glands of PLA2G10-Tg skin were hyperplasic. Proteolytic activation of sPLA(2)-X in PLA2G10-Tg skin was accompanied by preferential hydrolysis of phosphatidylethanolamine species with polyunsaturated fatty acids as well as elevated production of some if not all eicosanoids. Importantly, the skin of Pla2g10-deficient mice had abnormal hair follicles with noticeable reduction in a subset of hair genes, a hypoplasic outer root sheath, a reduced number of melanin granules, and unexpected up-regulation of prostanoid synthesis. Collectively, our study highlights the spatiotemporal expression of sPLA(2)-X in hair follicles, the presence of skin-specific machinery leading to sPLA(2)-X activation, a functional link of sPLA(2)-X with hair follicle homeostasis, and compartmentalization of the prostanoid pathway in hair follicles and epidermis.
Journal of Biological Chemistry 01/2011; 286(13):11616-31. · 4.77 Impact Factor
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ABSTRACT: Acute inflammation in healthy individuals is self-limiting and has an active termination program. The mechanisms by which acute inflammation is resolved are of interest. In murine zymosan-induced peritonitis, we found that eosinophils are recruited to the inflamed loci during the resolution phase of acute inflammation. In vivo depletion of eosinophils caused a resolution deficit, namely impaired lymphatic drainage with reduced appearance of phagocytes carrying engulfed zymosan in the draining lymph node, and sustained numbers of polymorphonuclear leukocytes in inflamed tissues. Liquid chromatography-tandem mass spectrometry-based lipidomics of the resolving exudates revealed that locally activated eosinophils in the resolution phase produced proresolving mediators, including protectin D1 (PD1) from docosahexaenoic acid. The resolution deficit caused by eosinophil depletion was rescued by eosinophil restoration or the administration of PD1. Eosinophils deficient in 12/15-lipoxygenase could not rescue the resolution phenotype. The present results indicate that mouse eosinophils and eosinophil-derived lipid mediators, including PD1, have a role in promoting the resolution of acute inflammation, expanding the roles of eosinophils in host defense and resolution.
The FASEB Journal 10/2010; 25(2):561-8. · 5.71 Impact Factor
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ABSTRACT: Recent epidemiological studies have shown a positive association of a high-fat diet with the risk of colon cancer. Indeed, increments in the serum levels of triglycerides (TG) and cholesterols are positively related with colon carcinogenesis. We previously reported that an age-dependent hyperlipidemic state is characteristic of Min mice, an animal model for human familial adenomatous polyposis (FAP). However, qualitative and quantitative changes of lipid metabolism are poorly understood in this state. Here, we provide detailed analysis of serum lipids in Min mice using reverse-phased liquid chromatography/electrospray ionization mass spectrometry (RPLC/ESI-MS). We also demonstrate local analysis of lipid droplets in the villi of the small intestine using laser capture microdissection and a sensitive chip-based nanoESI-MS system. As a result, oxidized phosphatidylcholines (PC) such as aldehyde and carboxylic acid types were increased, even at an early stage of intestinal polyp formation in serum. In addition, hydroperoxidizable TG precursors containing linoleic acid (18:2n-6) were deposited at the tip of the villi with aging, and these hydroperoxidized TG were also increased in serum. Meanwhile, increments of the oxidizable TG precursors in serum and small intestinal mucosa were suppressed by treatment with pitavastatin, a novel third generation lipophilic statin. These results suggest that quantitative and qualitative lipid changes such as hydroperoxidizable TG precursors are important in the course of intestinal polyp formation and oxidative stress might lead to the development of intestinal polyp formation in Min mice.
Cancer Science 09/2010; 102(1):79-87. · 3.33 Impact Factor
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Hisayuki Horai,
Masanori Arita,
Shigehiko Kanaya,
Yoshito Nihei,
Tasuku Ikeda,
Kazuhiro Suwa,
Yuya Ojima,
Kenichi Tanaka,
Satoshi Tanaka,
Ken Aoshima, [......],
Daisuke Shibata,
Steffen Neumann,
Takashi Iida,
Ken Tanaka,
Kimito Funatsu,
Fumito Matsuura,
Tomoyoshi Soga,
Ryo Taguchi,
Kazuki Saito,
Takaaki Nishioka
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ABSTRACT: MassBank is the first public repository of mass spectra of small chemical compounds for life sciences (<3000 Da). The database contains 605 electron-ionization mass spectrometry (EI-MS), 137 fast atom bombardment MS and 9276 electrospray ionization (ESI)-MS(n) data of 2337 authentic compounds of metabolites, 11 545 EI-MS and 834 other-MS data of 10,286 volatile natural and synthetic compounds, and 3045 ESI-MS(2) data of 679 synthetic drugs contributed by 16 research groups (January 2010). ESI-MS(2) data were analyzed under nonstandardized, independent experimental conditions. MassBank is a distributed database. Each research group provides data from its own MassBank data servers distributed on the Internet. MassBank users can access either all of the MassBank data or a subset of the data by specifying one or more experimental conditions. In a spectral search to retrieve mass spectra similar to a query mass spectrum, the similarity score is calculated by a weighted cosine correlation in which weighting exponents on peak intensity and the mass-to-charge ratio are optimized to the ESI-MS(2) data. MassBank also provides a merged spectrum for each compound prepared by merging the analyzed ESI-MS(2) data on an identical compound under different collision-induced dissociation conditions. Data merging has significantly improved the precision of the identification of a chemical compound by 21-23% at a similarity score of 0.6. Thus, MassBank is useful for the identification of chemical compounds and the publication of experimental data.
Biological Mass Spectrometry 07/2010; 45(7):703-14. · 3.41 Impact Factor
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Hiroyasu Sato,
Yoshitaka Taketomi,
Yuki Isogai,
Yoshimi Miki,
Kei Yamamoto,
Seiko Masuda,
Tomohiko Hosono,
Satoru Arata,
Yukio Ishikawa,
Toshiharu Ishii,
Tetsuyuki Kobayashi, Hiroki Nakanishi,
Kazutaka Ikeda,
Ryo Taguchi,
Shuntaro Hara,
Ichiro Kudo,
Makoto Murakami
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ABSTRACT: Although lipid metabolism is thought to be important for the proper maturation and function of spermatozoa, the molecular mechanisms that underlie this dynamic process in the gonads remains incompletely understood. Here, we show that group III phospholipase A2 (sPLA2-III), a member of the secreted phospholipase A2 (sPLA2) family, is expressed in the mouse proximal epididymal epithelium and that targeted disruption of the gene encoding this protein (Pla2g3) leads to defects in sperm maturation and fertility. Although testicular spermatogenesis in Pla2g3-/- mice was grossly normal, spermatozoa isolated from the cauda epididymidis displayed hypomotility, and their ability to fertilize intact eggs was markedly impaired. Transmission EM further revealed that epididymal spermatozoa in Pla2g3-/- mice had both flagella with abnormal axonemes and aberrant acrosomal structures. During epididymal transit, phosphatidylcholine in the membrane of Pla2g3+/+ sperm underwent a dramatic shift in its acyl groups from oleic, linoleic, and arachidonic acids to docosapentaenoic and docosahexaenoic acids, whereas this membrane lipid remodeling event was compromised in sperm from Pla2g3-/- mice. Moreover, the gonads of Pla2g3-/- mice contained less 12/15-lipoxygenase metabolites than did those of Pla2g3+/+ mice. Together, our results reveal a role for the atypical sPLA2 family member sPLA2-III in epididymal lipid homeostasis and indicate that its perturbation may lead to sperm dysfunction.
The Journal of clinical investigation 05/2010; 120(5):1400-14. · 15.39 Impact Factor
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Hiroyuki Seki,
Koichi Fukunaga,
Makoto Arita,
Hiroyuki Arai, Hiroki Nakanishi,
Ryo Taguchi,
Taku Miyasho,
Rina Takamiya,
Koichiro Asano,
Akitoshi Ishizaka,
Junzo Takeda,
Bruce D Levy
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ABSTRACT: Whereas pneumonia is the most common cause of death and disability worldwide, most cases of pneumonia spontaneously resolve. Mechanisms that promote pneumonia resolution remain to be determined. Resolvin E1 (RvE1) is an endogenous mediator that displays proresolving actions in sterile inflammation. In this study, we developed a new model of aspiration pneumonia to evaluate the effect of RvE1 on acute lung injury caused by acid aspiration and subsequent bacterial challenge. Mice received hydrochloric acid into the left lung followed by the enteric pathogen Escherichia coli. I.v. administration of RvE1 (approximately 0.005 mg/kg) prior to acid injury selectively decreased lung neutrophil accumulation by 55% and enhanced clearance of E. coli. RvE1 significantly decreased lung tissue levels of several proinflammatory chemokines and cytokines, including IL-1beta, IL-6, HMGB-1, MIP-1alpha, MIP-1beta, keratinocyte-derived chemokine, and MCP-1, in a manner independent of the anti-inflammatory mediators IL-10 and lipoxin A4. In addition, animals treated with RvE1 had a marked improvement in survival. These findings in experimental aspiration pneumonia have uncovered protective roles for RvE1 in pathogen-mediated inflammation that are both anti-inflammatory for neutrophils and protective for host defense, suggesting that RvE1 represents the first candidate for a novel therapeutic strategy for acute lung injury and pneumonia that harnesses natural resolution mechanisms.
The Journal of Immunology 12/2009; 184(2):836-43. · 5.79 Impact Factor
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Jin Endo,
Motoaki Sano,
Takaharu Katayama,
Takako Hishiki,
Ken Shinmura,
Shintaro Morizane,
Tomohiro Matsuhashi,
Yoshinori Katsumata,
Yan Zhang,
Hideyuki Ito, [......],
Fumiyuki Hattori,
Vasilis Vasiliou,
Takeshi Adachi,
Ikuroh Ohsawa,
Ryo Taguchi,
Yoshio Hirabayashi,
Shigeo Ohta,
Makoto Suematsu,
Satoshi Ogawa,
Keiichi Fukuda
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ABSTRACT: Aldehyde accumulation is regarded as a pathognomonic feature of oxidative stress-associated cardiovascular disease.
We investigated how the heart compensates for the accelerated accumulation of aldehydes.
Aldehyde dehydrogenase 2 (ALDH2) has a major role in aldehyde detoxification in the mitochondria, a major source of aldehydes. Transgenic (Tg) mice carrying an Aldh2 gene with a single nucleotide polymorphism (Aldh2*2) were developed. This polymorphism has a dominant-negative effect and the Tg mice exhibited impaired ALDH activity against a broad range of aldehydes. Despite a shift toward the oxidative state in mitochondrial matrices, Aldh2*2 Tg hearts displayed normal left ventricular function by echocardiography and, because of metabolic remodeling, an unexpected tolerance to oxidative stress induced by ischemia/reperfusion injury. Mitochondrial aldehyde stress stimulated eukaryotic translation initiation factor 2alpha phosphorylation. Subsequent translational and transcriptional activation of activating transcription factor-4 promoted the expression of enzymes involved in amino acid biosynthesis and transport, ultimately providing precursor amino acids for glutathione biosynthesis. Intracellular glutathione levels were increased 1.37-fold in Aldh2*2 Tg hearts compared with wild-type controls. Heterozygous knockout of Atf4 blunted the increase in intracellular glutathione levels in Aldh2*2 Tg hearts, thereby attenuating the oxidative stress-resistant phenotype. Furthermore, glycolysis and NADPH generation via the pentose phosphate pathway were activated in Aldh2*2 Tg hearts. (NADPH is required for the recycling of oxidized glutathione.)
The findings of the present study indicate that mitochondrial aldehyde stress in the heart induces metabolic remodeling, leading to activation of the glutathione-redox cycle, which confers resistance against acute oxidative stress induced by ischemia/reperfusion.
Circulation Research 10/2009; 105(11):1118-27. · 9.49 Impact Factor
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ABSTRACT: Endogenous phosphatidylcholine in biological membranes exists as isomers with acyl moieties at the sn-1 or sn-2 positions of the glycerol backbone. However, detailed biochemical information on these positional isomers is not generally available. This study is the first report on the separation and identification of positional isomers of endogenous phosphatidylcholine using reversed-phase LC-ESIMS/MS. The separation of positional isomers in PC was achieved by using ultra performance LC, which uses a high-resolution HPLC system. To identify positional isomers in individual PC species, their lyso-PC-related fragments and fatty acids, which were obtained by MS/MS analysis in the negative ion mode, were used. From the application results of biological samples, the lipid extracts of mouse brain were found to be abundant in PC containing 22:6 at the sn-1 position of the glycerol backbone. However, the lipid extracts from mouse heart and liver were not abundant in positional isomers. This achievement demonstrates that the relative amounts of positional isomers in various tissues or molecular species differ. These results will be useful for the clarification of the biological mechanisms of remodelling enzymes such as phospholipase and acyltransferase. Thus, our report provides a novel and critical milestone in understanding how molecular composition of phospholipids is established and their biological roles.
Journal of biochemistry 10/2009; 147(2):245-56. · 1.95 Impact Factor
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ABSTRACT: TRIC channels function as monovalent cation-specific channels that mediate counter ion movements coupled with ryanodine receptor-mediated Ca(2+) release from intracellular stores in muscle cells. Mammalian tissues differentially contain two TRIC channel subtypes: TRIC-A is abundantly expressed in excitable cells, whereas TRIC-B is ubiquitously expressed throughout tissues. Here, we report the physiological role of TRIC-B channels in mouse perinatal development. TRIC-B-knockout neonates were cyanotic owing to respiratory failure and died shortly after birth. In the mutant neonates, the deflated lungs exhibited severe histological defects, and alveolar type II epithelial cells displayed ultrastructural abnormalities. The metabolic conversion of glycogen into phospholipids was severely interrupted in the mutant type II cells, and surfactant phospholipids secreted into the alveolar space were insufficient in the mutant neonates. Moreover, the mutant type II cells were compromised for Ca(2+) release mediated by inositol-trisphosphate receptors, despite Ca(2+) overloading in intracellular stores. Our results indicate that TRIC-B channels take an active part in Ca(2+) signalling to establish specialised functions in type II cells and are thus essential for perinatal lung maturation.
Development 08/2009; 136(14):2355-61. · 6.60 Impact Factor
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Satori Tokudome,
Motoaki Sano,
Ken Shinmura,
Tomohiro Matsuhashi,
Shintaro Morizane,
Hidenori Moriyama,
Kayoko Tamaki,
Kentaro Hayashida, Hiroki Nakanishi,
Noritada Yoshikawa, [......],
Ruri Kaneda,
Kengo Tomita,
Naomi Eguchi,
Yoshihiro Urade,
Koichiro Asano,
Yasunori Utsunomiya,
Takeshi Suzuki,
Ryo Taguchi,
Hirotoshi Tanaka,
Keiichi Fukuda
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ABSTRACT: Lipocalin-type prostaglandin D synthase (L-PGDS), which was originally identified as an enzyme responsible for PGD2 biosynthesis in the brain, is highly expressed in the myocardium, including in cardiomyocytes. However, the factors that control expression of the gene encoding L-PGDS and the pathophysiologic role of L-PGDS in cardiomyocytes are poorly understood. In the present study, we demonstrate that glucocorticoids, which act as repressors of prostaglandin biosynthesis in most cell types, upregulated the expression of L-PGDS together with cytosolic calcium-dependent phospholipase A2 and COX2 via the glucocorticoid receptor (GR) in rat cardiomyocytes. Accordingly, PGD2 was the most prominently induced prostaglandin in vivo in mouse hearts and in vitro in cultured rat cardiomyocytes after exposure to GR-selective agonists. In isolated Langendorff-perfused mouse hearts, dexamethasone alleviated ischemia/reperfusion injury. This cardioprotective effect was completely abrogated by either pharmacologic inhibition of COX2 or disruption of the gene encoding L-PGDS. In in vivo ischemia/reperfusion experiments, dexamethasone reduced infarct size in wild-type mice. This cardioprotective effect of dexamethasone was markedly reduced in L-PGDS-deficient mice. In cultured rat cardiomyocytes, PGD2 protected against cell death induced by anoxia/reoxygenation via the D-type prostanoid receptor and the ERK1/2-mediated pathway. Taken together, these results suggest what we believe to be a novel interaction between glucocorticoid-GR signaling and the cardiomyocyte survival pathway mediated by the arachidonic acid cascade.
The Journal of clinical investigation 06/2009; 119(6):1477-88. · 15.39 Impact Factor
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ABSTRACT: Previous studies have shown that MALDI-imaging mass spectrometry (IMS) can be used to visualize the distribution of various biomolecules, especially lipids, in the cells and tissues. In this study, we report the cell-selective distribution of PUFA-containing glycerophospholipids (GPLs) in the mouse brain. We established a practical experimental procedure for the IMS of GPLs. We demonstrated that optimization of the composition of the matrix solution and spectrum normalization to the total ion current (TIC) is critical. Using our procedure, we simultaneously differentiated and visualized the localizations of specific molecular species of GPLs in mouse brain sections. The results showed that PUFA-containing phosphatidylcholines (PCs) were distributed in a cell-selective manner: arachidonic acid- and docosahexaenoic acid-containing PCs were seen in the hippocampal neurons and cerebellar Purkinje cells, respectively. Furthermore, these characteristic localizations of PUFA-PCs were formed during neuronal maturation. The phenomenon of brain cell-selective production of specific PUFA-GPLs will help elucidate the potential physiological functions of PUFAs in specific brain regions.
The Journal of Lipid Research 06/2009; 50(9):1776-88. · 5.56 Impact Factor
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ABSTRACT: p2y5 is an orphan G protein-coupled receptor that is closely related to the fourth lysophosphatidic acid (LPA) receptor, LPA4. Here we report that p2y5 is a novel LPA receptor coupling to the G13-Rho signaling pathway. "LPA receptor-null" RH7777 and B103 cells exogenously expressing p2y5 showed [3H]LPA binding, LPA-induced [35S]guanosine 5'-3-O-(thio)triphosphate binding, Rho-dependent alternation of cellular morphology, and Gs/13 chimeric protein-mediated cAMP accumulation. LPA-induced contraction of human umbilical vein endothelial cells was suppressed by small interfering RNA knockdown of endogenously expressed p2y5. We also found that 2-acyl-LPA had higher activity to p2y5 than 1-acyl-LPA. A recent study has suggested that p2y5 is an LPA receptor essential for human hair growth. We confirmed that p2y5 is a functional LPA receptor and propose to designate this receptor LPA6.
Journal of Biological Chemistry 05/2009; 284(26):17731-41. · 4.77 Impact Factor
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ABSTRACT: In this chapter we are going to mention about three different approaches in lipidomics and how to effectively profile or calculate the amounts of phospholipids from major molecular species up to minor ones. 1) Precise identification and profiling of individual molecular species of phospholipids by data-dependent LC-ESIMS/MS combination with "Lipid Search". We have been using this method as a global analysis of phospholipid. We usually applied this method at least once for new biological samples. We constructed an automated search engine, "Lipid Search", for identification and profiling of phospholipids. Once after applying this analysis, a specified retention time can be obtained for each elution peak of individual phospholipid molecular species. Thus, reproducible identification results can be effectively obtained by our search engine from the data obtained by single LC or combination of LC with specified head group survey by using precursor ion scanning or neutral loss scanning. 2) An effective analytical method of LC-ESIMS for the identification of acidic phospholipids such as phosphatidic acid and phosphatidylserine. This is an approach of how to obtain sharp chromatographic peaks for acidic lipids such as phosphatidic acid and phosphatidylserine that are normally detected as broad elution peaks. With this improvement very small amount of molecular species in minor acidic phospholipids were effectively obtained. 3) Identification and profiling of molecular species in focused phospholipids. Third one is a combination analysis of focused methods such as precursor ion scanning or neutral loss scanning and high efficient LC separation. As reported previously, different combinations of fatty acids on sn-1 and sn-2 can be mostly detected as separate peaks by reverse phase LC-ESIMS. Detection limit of precursor ion scanning or neutral loss scanning is more than ten times higher than that of the method without LC separation, because of decreased ion suppression. We will mention about application of this methods for focused analysis on phosphatidylethanolamine-plasmalogens.
Methods in molecular biology (Clifton, N.J.) 01/2009; 579:287-313.
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ABSTRACT: Recently, it was reported that oxidized phosphatidylcholine shows biological activities via scavenger receptor CD36 or Toll-like receptor 4 (TLR4)-TRIF. Thus, the analysis of oxidized phospholipids is essential in understanding these biological roles. Here, we report an analytical method for oxidized phosphatidylcholines using multiple reaction monitoring (MRM) with theoretically expanded data sets. This analytical method was performed by a quadrupole linear ion trap mass spectrometer with ultra performance LC (UPLC). To investigate whether this established analytical method was applicable to biological samples, we performed variation analysis of oxidized PCs using a myocardial ischemia-reperfusion model. Most oxidized PCs were detected in higher amounts in the ischemic myocardium than in the non-ischemic myocardium. From these application results, this established method is a valuable tool for the global analysis of oxidized PCs. In the future, our study can provide further understanding of how oxidized phospholipids are produced and are correlated to various diseases.
Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 11/2008; 877(13):1366-74. · 2.78 Impact Factor
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ABSTRACT: We recently developed a matrix-assisted laser desorption/ionization quadrupole ion trap time-of-flight (MALDI-QIT-TOF)-based imaging mass spectrometry (IMS) system. This system enables us to perform structural analyses using tandem mass spectrometry (MS/MS), as well as to visualize phospholipids and peptides in frozen sections. In the retina, phototransduction is regulated by the light-sensitive interaction between visual pigment-coupled receptor proteins, such as rhodopsin, and G proteins, such as transducin. There are some reports that the conformation of rhodopsin is influenced by the composition of phospholipids in the lipid bilayer membrane. However, these results were based on in vitro experiments and have not been analyzed in vivo. In this study, we visualized and identified phospholipids in mouse retinal sections with the MALDI-QIT-TOF-based IMS system. From a spectrum obtained by raster-scanned analysis of the sections, ions with high signal intensities were selected and analyzed by MS/MS. As a result, sixteen ions were identified as being from four diacyl-phosphatidylcholine (PC) species, i.e., PC (16:0/16:0), PC (16:0/18:1), PC (16:0/22:6), and PC (18:0/22:6), with different ion forms. The ion images revealed different distributions on the retinal sections: PC (16:0/18:1) was distributed in the inner nuclear layer and outer plexiform layer, PC (16:0/16:0) in the outer nuclear layer and inner segment, and both PC (16:0/22:6) and PC (18:0/22:6) in the outer segment and pigment epithelium. In conclusion, our in vivo IMS analyses demonstrated a three-zone distribution of PC species on the retinal sections. This approach may be useful for analyzing lipid changes and their contribution to phototransduction in the retina.
Rapid Communications in Mass Spectrometry 10/2008; 22(21):3415-26. · 2.79 Impact Factor
