Kei Yamamoto, Yoshimi Miki, H. Sato, R. Murase, Y. Taketomi and M. Murakami : Secreted Phospholipase A2 Specificity on Natural Membrane Phospholipids, Nov. 2016.
(Summary)
The secreted phospholipase A2 (sPLA2) family contains 10 catalytically active isoforms. Current in vitro biochemical studies have shown that individual sPLA2s have distinct substrate selectivity in terms of the polar head groups or sn-2 fatty acids of their substrate phospholipids. Importantly, transgenic or knockout mice for distinct sPLA2s display nonoverlapping phenotypes, arguing that they do act on different phospholipid substrates and mobilize unique lipid metabolites in vivo. In an effort to comprehensively understand lipid metabolism driven by individual sPLA2s under pathophysiological conditions, we took advantages of mass spectrometric lipidomics technology to monitor the spatiotemporal changes in phospholipids (substrates) and products (fatty acids, lysophospholipids, and their metabolites) in tissues or cells of sPLA2-transgenic or knockout mice. The in vivo lipidomic data were compared with the in vitro activity of recombinant sPLA2s toward phospholipid mixtures extracted from the target tissues, cells, or extracellular membrane components on which sPLA2s may intrinsically act. These approaches reveal that the overall tendency in in vitro assays using natural membranes is recapitulated in several in vivo systems, often with even more selective patterns of hydrolysis. In this chapter, we will summarize current understanding of the in vivo substrate specificity of sPLA2s toward natural membrane phospholipids.
M. Murakami, K. Yamamoto, Yoshimi Miki, R. Murase, H. Sato and Y. Taketomi : The Roles of the Secreted Phospholipase A2 Gene Family in Immunology, Jun. 2016.
(Summary)
Within the phospholipase A2 (PLA2) family that hydrolyzes phospholipids to yield fatty acids and lysophospholipids, secreted PLA2 (sPLA2) enzymes comprise the largest group containing 11 isoforms in mammals. Individual sPLA2s exhibit unique tissue or cellular distributions and enzymatic properties, suggesting their distinct biological roles. Although PLA2 enzymes, particularly cytosolic PLA2 (cPLA2α), have long been implicated in inflammation by driving arachidonic acid metabolism, the precise biological roles of sPLA2s have remained a mystery over the last few decades. Recent studies employing mice gene-manipulated for individual sPLA2s, in combination with mass spectrometric lipidomics to identify their target substrates and products in vivo, have revealed their roles in diverse biological events, including immunity and associated disorders, through lipid mediator-dependent or -independent processes in given microenvironments. In this review, we summarize our current knowledge of the roles of sPLA2s in various immune responses and associated diseases.
Mamun Mohammad Sikder, Sumire Sasaki, Yoshimi Miki, Yuki Nagasaki, ichi Ken Ohta, Zahir Hussain, Hiroyuki Saiga, Mari Ohmura-Hoshino, Katsuaki Hoshino, Masaki Ueno, Miki Okada-Iwabu, Makoto Murakami, Natsuo Ueda and Toru Uyama : PLAAT5 as an N-acyltransferase responsible for the generation of anti-inflammatory N-acylethanolamines in testis, Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids, 1870, 2, 159583, 2024.
(Summary)
N-Acylethanolamines (NAEs) are a class of lipid mediators that exhibit anti-inflammatory and appetite-suppressive activities. Among them, palmitoylethanolamide (PEA) and arachidonoylethanolamide (AEA) bind to peroxisomal proliferator-activated receptor (PPAR) α and cannabinoid receptor CB1, respectively. N-Acyl-phosphatidylethanolamine (NAPE) as a precursor of NAEs is biosynthesized from membrane phospholipids by N-acyltransferases, which consist of group IVE cytosolic phospholipase A2ϵ (cPLA2ϵ) and PLAAT (phospholipase A and acyltransferase) family enzymes. While cPLA2ϵ is responsible for the production of NAEs not only in specific tissues, including muscle, skin, and the stomach, but also under pathological conditions, such as psoriasis and brain ischemia, the involvement of the PLAAT family in vivo remains unclear. Considering the specific expression of PLAAT5 in testes, we investigated the potential role of PLAAT5 in the formation of NAEs in testes using PLAAT5-deficient (Plaat5-/-) mice. High-performance liquid chromatography coupled with tandem mass spectrometry showed that PLAAT5 deficiency decreased the total level of NAEs by 61 %, with PEA and AEA being reduced by 64 % and 87 %, respectively. Following a treatment with cadmium chloride, an environmental toxin that induces testicular inflammation, the expression of inflammatory genes (Il6, Tnf, and Nos2) in testes was markedly higher in Plaat5-/- mice than in Plaat5+/+ mice, and their expression was attenuated by the administration of PEA and AEA. Furthermore, these anti-inflammatory effects were canceled by a co-treatment with the antagonists of PPARα or CB1. These results suggest that PLAAT5 is responsible for the biosynthesis of anti-inflammatory NAEs in testes.
(Keyword)
Anti-inflammation / N-acylethanolamine / N-acyltransferase / PLAAT / Testis
Interaction of mast cells (MCs) with fibroblasts is essential for MC maturation within tissue microenvironments, although the underlying mechanism is incompletely understood. Through a phenotypic screening of >30 mouse lines deficient in lipid-related genes, we found that deletion of the lysophosphatidic acid (LPA) receptor LPA1, like that of the phospholipase PLA2G3, the prostaglandin D2 (PGD2) synthase L-PGDS, or the PGD2 receptor DP1, impairs MC maturation and thereby anaphylaxis. Mechanistically, MC-secreted PLA2G3 acts on extracellular vesicles (EVs) to supply lysophospholipids, which are converted by fibroblast-derived autotaxin (ATX) to LPA. Fibroblast LPA1 then integrates multiple pathways required for MC maturation by facilitating integrin-mediated MC-fibroblast adhesion, IL-33-ST2 signaling, L-PGDS-driven PGD2 generation, and feedforward ATX-LPA1 amplification. Defective MC maturation resulting from PLA2G3 deficiency is restored by supplementation with LPA1 agonists or PLA2G3-modified EVs. Thus, the lipid-orchestrated paracrine circuit involving PLA2G3-driven lysophospholipid, eicosanoid, integrin, and cytokine signaling fine-tunes MC-fibroblast communication, ensuring MC maturation.
Asako Hamu-Tanoue, Koichi Takagi, Yoshitaka Taketomi, Yoshimi Miki, Yasumasa Nishito, Kuniyuki Kano, Junken Aoki, Takahiro Matsuyama, Kiyotaka Kondo, Yoichi Dotake, Hiromi Matsuyama, Kentaro Machida, Makoto Murakami and Hiromasa Inoue : Group III secreted phospholipase A2-driven lysophospholipid pathway protects against allergic asthma, The FASEB journal, 38, 2, e23428, 2024.
(Summary)
Asthma is a chronic inflammatory disease of the airways characterized by recurrent episodes of airway obstruction, hyperresponsiveness, remodeling, and eosinophilia. Phospholipase A2 s (PLA2 s), which release fatty acids and lysophospholipids from membrane phospholipids, have been implicated in exacerbating asthma by generating pro-asthmatic lipid mediators, but an understanding of the association between individual PLA2 subtypes and asthma is still incomplete. Here, we show that group III-secreted PLA2 (sPLA2 -III) plays an ameliorating, rather than aggravating, role in asthma pathology. In both mouse and human lungs, sPLA2 -III was expressed in bronchial epithelial cells and decreased during the asthmatic response. In an ovalbumin (OVA)-induced asthma model, Pla2g3-/- mice exhibited enhanced airway hyperresponsiveness, eosinophilia, OVA-specific IgE production, and type 2 cytokine expression as compared to Pla2g3+/+ mice. Lipidomics analysis showed that the pulmonary levels of several lysophospholipids, including lysophosphatidylcholine, lysophosphatidylethanolamine, and lysophosphatidic acid (LPA), were decreased in OVA-challenged Pla2g3-/- mice relative to Pla2g3+/+ mice. LPA receptor 2 (LPA2 ) agonists suppressed thymic stromal lymphopoietin (TSLP) expression in bronchial epithelial cells and reversed airway hyperresponsiveness and eosinophilia in Pla2g3-/- mice, suggesting that sPLA2 -III negatively regulates allergen-induced asthma at least by producing LPA. Thus, the activation of the sPLA2 -III-LPA pathway may be a new therapeutic target for allergic asthma.
Macrophages are essential for the proper inflammatory and reparative processes that lead to regeneration of skeletal muscle after injury. Recent studies have demonstrated close links between the function of activated macrophages and their cellular metabolism. Sterol regulatory element-binding protein 1 (SREBP1) is a key regulator of lipid metabolism and has been shown to affect the activated states of macrophages. However, its role in tissue repair and regeneration is poorly understood. Here we show that systemic deletion of Srebf1, encoding SREBP1, or macrophage-specific deletion of Srebf1a, encoding SREBP1a, delays resolution of inflammation and impairs skeletal muscle regeneration after injury. Srebf1 deficiency impairs mitochondrial function in macrophages and suppresses the accumulation of macrophages at sites of muscle injury. Lipidomic analyses showed the reduction of major phospholipid species in Srebf1-/- muscle myeloid cells. Moreover, diet supplementation with eicosapentaenoic acid restored the accumulation of macrophages and their mitochondrial gene expression and improved muscle regeneration. Collectively, our results demonstrate that SREBP1 in macrophages is essential for repair and regeneration of skeletal muscle after injury and suggest that SREBP1-mediated fatty acid metabolism and phospholipid remodeling are critical for proper macrophage function in tissue repair.
Haruka Hakoi, Yoshimi Miki, Saki Nomura, Kimiko Nakajima, Chiaki Terashima-Murase, Takuya Takeichi, Shigetoshi Sano, Masashi Akiyama, ichi Shin Sakasegawa, Makoto Murakami and Kei Yamamoto : Lysophospholipase D from Thermocrispum limits psoriatic inflammation by hydrolyzing epidermal lysoplasmalogen produced by group IIF secreted phospholipase A2, Biochimie, 215, 75-87, 2023.
(Summary)
Epidermal lipids play important roles in skin homeostasis and diseases. Psoriasis is an inflammatory disease characterized by keratinocyte hyperproliferation and Th17 immune responses. We previously reported that ethanolamine-type lysoplasmalogen (P-LPE), preferentially produced by group IIF secreted PLA2 (sPLA2-IIF/PLA2G2F) that is expressed in the suprabasal epidermis, promotes epidermal hyperplasia in psoriatic inflammation. Herein, we show that forcible degradation of epidermal P-LPE by topical application of recombinant lysophospholipase D (LyPls-PLD) from Thermocrispum, a lysoplasmalogen-specific hydrolase, attenuated epidermal hyperplasia and inflammation in imiquimod-induced and K5.Stat3C-transgenic mouse psoriasis models. In humans, P-LPE levels were elevated in the tape-stripped stratum corneum of patients with psoriasis. Moreover, in primary cultured human epidermal keratinocytes, aberrant cell proliferation and activation by psoriatic cytokines were sPLA2-IIF/P-LPE-dependent and were suppressed by the addition of LyPls-PLD with a decrease in P-LPE. These findings confirm that the sPLA2-IIF/P-LPE axis in the epidermis indeed regulates psoriasis, that P-LPE is a lipid biomarker that predicts the severity of psoriasis, and that pharmacological removal of this bioactive lipid is useful to prevent the disease. Thus, our study may lead to the development of drug discovery and diagnostic techniques based on this pathway.
(Keyword)
Group IIF phospholipase A2 / Lipidomics / Lysoplasmalogen / Psoriasis / Thermocrispum lysophospholipase D
The brain is generally resistant to regeneration after damage. The cerebral endogenous mechanisms triggering brain self-recovery have remained unclarified to date. We here discovered that the secreted phospholipase PLA2G2E from peri-infarct neurons generated dihomo-γ-linolenic acid (DGLA) as necessary for triggering brain-autonomous neural repair after ischemic brain injury. Pla2g2e deficiency diminished the expression of peptidyl arginine deiminase 4 (Padi4), a global transcriptional regulator in peri-infarct neurons. Single-cell RNA sequencing (scRNA-seq) and epigenetic analysis demonstrated that neuronal PADI4 had the potential for the transcriptional activation of genes associated with recovery processes after ischemic stroke through histone citrullination. Among various DGLA metabolites, we identified 15-hydroxy-eicosatrienoic acid (15-HETrE) as the cerebral metabolite that induced PADI4 in peri-infarct-surviving neurons. Administration of 15-HETrE enhanced functional recovery after ischemic stroke. Thus, our research clarifies the promising potential of brain-autonomous neural repair triggered by the specialized lipids that initiate self-recovery processes after brain injury.
M.Khaledur S. Rahman, Sumire Sasaki, Toru Uyama, Zahir Hussain, Mamun Mohammad Sikder, Hiroyuki Saiga, Mari Ohmura-Hoshino, ichi Ken Ohta, Yoshimi Miki, Katsuaki Hoshino, Masaki Ueno, Makoto Murakami and Natsuo Ueda : PLAAT1 deficiency alleviates high-fat diet-induced hepatic lipid accumulation in mice, The FASEB journal, 37, 7, e23032, 2023.
(Summary)
The phospholipase A and acyltransferase (PLAAT) family is composed of three isoforms in mice (PLAAT1, 3, and 5), all of which function as phospholipid-metabolizing enzymes exhibiting phospholipase A1 /A2 and acyltransferase activities. Plaat3-deficient (Plaat3-/- ) mice were previously reported to show lean phenotype and remarkable hepatic fat accumulation under high-fat diet (HFD) feeding, while Plaat1-/- mice have not been analyzed. In the present study, we generated Plaat1-/- mice and investigated the effects of PLAAT1 deficiency on HFD-induced obesity, hepatic lipid accumulation, and insulin resistance. After HFD treatment, PLAAT1 deficiency caused a lower body weight gain compared to wild-type mice. Plaat1-/- mice also showed reduced liver weight with negligible hepatic lipid accumulation. In accordance with these findings, PLAAT1 deficiency improved HFD-induced hepatic dysfunction and lipid metabolism disorders. Lipidomics analysis in the liver revealed that in Plaat1-/- mice, the levels of various glycerophospholipids tended to increase, while all classes of lysophospholipids examined tended to decrease, suggesting that PLAAT1 functions as phospholipase A1 /A2 in the liver. Interestingly, the HFD treatment of wild-type mice significantly increased the mRNA level of PLAAT1 in the liver. Furthermore, the deficiency did not appear to elevate the risk of insulin resistance in contrast to PLAAT3 deficiency. These results suggested that the suppression of PLAAT1 improves HFD-induced overweight and concomitant hepatic lipid accumulation.
Tetsuya Hirabayashi, Mai Kawaguchi, Sayaka Harada, Misa Mouri, Rina Takamiya, Yoshimi Miki, Hiroyasu Sato, Yoshitaka Taketomi, Kohei Yokoyama, Tetsuyuki Kobayashi, M. Suzumi Tokuoka, Yoshihiro Kita, Emiko Yoda, Shuntaro Hara, Kyohei Mikami, Yasumasa Nishito, Norihito Kikuchi, Rieko Nakata, Mari Kaneko, Hiroshi Kiyonari, Kohji Kasahara, Toshiki Aiba, Kazutaka Ikeda, Tomoyoshi Soga, Makoto Kurano, Yutaka Yatomi and Makoto Murakami : Hepatic phosphatidylcholine catabolism driven by PNPLA7 and PNPLA8 supplies endogenous choline to replenish the methionine cycle with methyl groups, Cell Reports, 42, 2, 111940, 2023.
(Summary)
Choline supplies methyl groups for regeneration of methionine and the methyl donor S-adenosylmethionine in the liver. Here, we report that the catabolism of membrane phosphatidylcholine (PC) into water-soluble glycerophosphocholine (GPC) by the phospholipase/lysophospholipase PNPLA8-PNPLA7 axis enables endogenous choline stored in hepatic PC to be utilized in methyl metabolism. PNPLA7-deficient mice show marked decreases in hepatic GPC, choline, and several metabolites related to the methionine cycle, accompanied by various signs of methionine insufficiency, including growth retardation, hypoglycemia, hypolipidemia, increased energy consumption, reduced adiposity, increased fibroblast growth factor 21 (FGF21), and an altered histone/DNA methylation landscape. Moreover, PNPLA8-deficient mice recapitulate most of these phenotypes. In contrast to wild-type mice fed a methionine/choline-deficient diet, both knockout strains display decreased hepatic triglyceride, likely via reductions of lipogenesis and GPC-derived glycerol flux. Collectively, our findings highlight the biological importance of phospholipid catabolism driven by PNPLA8/PNPLA7 in methyl group flux and triglyceride synthesis in the liver.
Izumi Tsukayama, Yuki Kawakami, Asako Tamenobu, Keisuke Toda, Saya Maruoka, Yuki Nagasaki, Yoshiko Mori, Risa Sawazumi, Kensuke Okamoto, Keita Kanzaki, Hideyuki Ito, Yoshitaka Takahashi, Yoshimi Miki, Kei Yamamoto, Makoto Murakami and Toshiko Suzuki-Yamamoto : Malabaricone C derived from nutmeg inhibits arachidonate 5-lipoxygenase activity and ameliorates psoriasis-like skin inflammation in mice, Free Radical Biology and Medicine, 193, Pt 1, 1-8, 2022.
(Summary)
As pro-inflammatory lipid mediators, leukotrienes have pathophysiological activities in several inflammatory diseases, including psoriasis. In the biosynthesis of leukotrienes from arachidonic acid, 5-lipoxygenase catalyzes the first two steps. In the present study, we showed that nutmeg (Myristica fragrans) strongly inhibited the catalytic activity of 5-lipoxygenase. To characterize the bioactive component(s) of nutmeg, we performed 5-lipoxygenase inhibitory activity-guided fractionation of aqueous ethanol extract of nutmeg, resulting in the isolation of malabaricone C having antioxidant activity. Malabaricone C exhibited potent competitive inhibition of 5-lipoxygenase with an IC50 value of 0.2 μM. In mice with imiquimod-induced psoriasis-like skin lesions, topical application of 2 mM malabaricone C significantly ameliorated hyperplasia and inflammatory cell infiltration, and suppressed the expression of the psoriasis-associated genes S100a9, Krt1, Il17a, and Il22. Lipid metabolome analysis of these psoriasis-like skin lesions showed that malabaricone C markedly decreased the level of leukotriene B4 but did not significantly increase the other pro-inflammatory lipid mediators. These findings suggest that malabaricone C decreases LTB4 by the 5-lipoxygenase inhibition and ameliorates the symptoms of psoriasis-like skin inflammation.
Yuki Nagasaki, Erika Kawai, Saya Maruoka, Miho Osumi, Izumi Tsukayama, Yuki Kawakami, Yoshitaka Takahashi, Yuka Okazaki, Yoshimi Miki, Yoshitaka Taketomi, Kei Yamamoto, Makoto Murakami and Toshiko Suzuki-Yamamoto : Lipid profiling reveals the presence of unique lipid mediators in human milk from healthy and mastitic subjects, Biochemical and Biophysical Research Communications, 630, 84-91, 2022.
(Summary)
Milk lipids are an important energy source for infants, but the composition of milk lipids has not yet been clarified in detail. In this study, we analyzed free fatty acids and their metabolites in milk from humans and cows. In comparison to cow milk, human milk showed a higher content of free fatty acids including polyunsaturated fatty acids, especially ω-3 fatty acids and their metabolites. Polyunsaturated fatty acids were enriched at an early period of lactation, while saturated fatty acids did not change significantly over the period. Moreover, human milk contained high levels of ω-3 fatty acid metabolites, particularly 18-hydroxyeicosapentaenoic acid, an eicosapentaenoic acid-derived metabolite with anti-inflammatory activity. In comparison with human normal milk, thromboxane B2 and protectin D1 levels were significantly elevated in milk from individuals with mastitis, suggesting that these lipid mediators could be potential biomarkers of obstructive mastitis. Overall, the unique lipid profile of human milk supports the efficacy of breast-feeding for supply of more nutritional and bioactive lipids in comparison to artificial or cow milk to infants, in whom digestive and absorptive functions are still immature.
Makoto Murakami, Rina Takamiya, Yoshimi Miki, Nao Sugimoto, Yuki Nagasaki, Toshiko Suzuki-Yamamoto and Yoshitaka Taketomi : Segregated functions of two cytosolic phospholipase A2 isoforms (cPLA2α and cPLA2ϵ) in lipid mediator generation, Biochemical Pharmacology, 203, 115176, 2022.
(Summary)
Among the phospholipase A2 (PLA2) superfamily, group IVA cytosolic PLA2 (cPLA2α) is currently attracting much attention as a central regulator of arachidonic acid (AA) metabolism linked to eicosanoid biosynthesis. Following cell activation, cPLA2α selectively releases AA, a precursor of a variety of eicosanoids, from phospholipids in perinuclear membrane compartments. cPLA2α-null mice display various phenotypes that could be largely explained by reduced eicosanoid signaling. In contrast, group IVE cPLA2ϵ, another member of the cPLA2 family, acts as a Ca2+-dependent N-acyltransferase rather than a PLA2, thereby regulating the biosynthesis of N-acylethanolamines (NAEs), a unique class of lipid mediators with an anti-inflammatory effect. In response to Ca2+ signaling, cPLA2ϵ translocates to phosphatidylserine-rich organelle membranes in the endocytic/recycling pathway. In vivo, cPLA2ϵ is induced in keratinocytes of psoriatic skin, and its genetic deletion exacerbates psoriatic inflammation due to a marked reduction of NAE-related lipids. cPLA2ϵ also contributes to NAE generation in several if not all mouse tissues. Thus, the two members of the cPLA2 family, cPLA2α and cPLA2ϵ, catalyze distinct enzymatic reactions to mobilize distinct sets of lipid mediators, thereby differently regulating pathophysiological events in health and disease. Such segregation of the cPLA2α-eicosanoid and cPLA2ϵ-NAE pathways represents a new paradigm of research on PLA2s and lipid mediators.
Luyiyun Liang, Rina Takamiya, Yoshimi Miki, Kanako Heike, Yoshitaka Taketomi, Nao Sugimoto, Midori Yamaguchi, Hiroshi Shitara, Yasumasa Nishito, Tetsuyuki Kobayashi, Tetsuya Hirabayashi and Makoto Murakami : Group IVE cytosolic phospholipase A2 limits psoriatic inflammation by mobilizing the anti-inflammatory lipid N-acylethanolamine, The FASEB journal, 36, 5, e22301, 2022.
(Summary)
Psoriasis is an inflammatory disorder characterized by keratinocyte hyper-proliferation and Th17-type immune responses. However, the roles of bioactive lipids and the regulation of their biosynthesis in this chronic skin disease are not fully understood. Herein, we show that group IVE cytosolic phospholipase A2 (cPLA2 ϵ/PLA2G4E) plays a counterregulatory role against psoriatic inflammation by producing the anti-inflammatory lipid N-acylethanolamine (NAE). Lipidomics analysis of mouse skin revealed that NAE species and their precursors (N-acyl-phosphatidylethanolamine and glycerophospho-N-acylethanolamine) were robustly increased in parallel with the ongoing process of imiquimod (IMQ)-induced psoriasis, accompanied by a marked upregulation of cPLA2 ϵ in epidermal keratinocytes. Genetic deletion of cPLA2 ϵ exacerbated IMQ-induced ear swelling and psoriatic marker expression, with a dramatic reduction of NAE-related lipids in IMQ-treated, and even normal, skin. Stimulation of cultured human keratinocytes with psoriatic cytokines concomitantly increased PLA2G4E expression and NAE production, and supplementation with NAEs significantly attenuated the cytokine-induced upregulation of the psoriatic marker S100A9. Increased expression of cPLA2 ϵ was also evident in the epidermis of psoriatic patients. These findings reveal for the first time the in vivo role of cPLA2 ϵ, which is highly induced in the keratinocytes of the psoriatic skin, promotes the biosynthesis of NAE-related lipids, and contributes to limiting psoriatic inflammation.
Kai Kudo, Yoshimi Miki, Joaquim Carreras, Shunya Nakayama, Yasushi Nakamoto, Masatoshi Ito, Etsuko Nagashima, Kei Yamamoto, Hiroshi Higuchi, ya Shin Morita, Asuka Inoue, Junken Aoki, Kiyoshi Ando, Naoya Nakamura, Makoto Murakami and Ai Kotani : Secreted phospholipase A2 modifies extracellular vesicles and accelerates B cell lymphoma, Cell Metabolism, 34, 4, 615-633.e8, 2022.
(Summary)
Extracellular vesicles (EVs) including exosomes act as intercellular communicators by transferring protein and microRNA cargoes, yet the role of EV lipids remains unclear. Here, we show that the pro-tumorigenic action of lymphoma-derived EVs is augmented via secreted phospholipase A2 (sPLA2)-driven lipid metabolism. Hydrolysis of EV phospholipids by group X sPLA2, which was induced in macrophages of Epstein-Barr virus (EBV) lymphoma, increased the production of fatty acids, lysophospholipids, and their metabolites. sPLA2-treated EVs were smaller and self-aggregated, showed better uptake, and increased cytokine expression and lipid mediator signaling in tumor-associated macrophages. Pharmacological inhibition of endogenous sPLA2 suppressed lymphoma growth in EBV-infected humanized mice, while treatment with sPLA2-modified EVs reversed this phenotype. Furthermore, sPLA2 expression in human large B cell lymphomas inversely correlated with patient survival. Overall, the sPLA2-mediated EV modification promotes tumor development, highlighting a non-canonical mechanistic action of EVs as an extracellular hydrolytic platform of sPLA2.
Yoshimi Miki, Yoshitaka Taketomi, Yuh Kidoguchi, Kei Yamamoto, Kazuaki Muramatsu, Yasumasa Nishito, Jonguk Park, Koji Hosomi, Kenji Mizuguchi, Jun Kunisawa, Tomoyoshi Soga, Eric Boilard, B. Siddabasave Gowda Gowda, Kazutaka Ikeda, Makoto Arita and Makoto Murakami : Group IIA secreted phospholipase A2 controls skin carcinogenesis and psoriasis by shaping the gut microbiota, JCI Insight, 7, 2, 2022.
(Summary)
Besides promoting inflammation by mobilizing lipid mediators, group IIA secreted phospholipase A2 (sPLA2-IIA) prevents bacterial infection by degrading bacterial membranes. Here, we show that, despite the restricted intestinal expression of sPLA2-IIA in BALB/c mice, its genetic deletion leads to amelioration of cancer and exacerbation of psoriasis in distal skin. Intestinal expression of sPLA2-IIA is reduced after treatment with antibiotics or under germ-free conditions, suggesting its upregulation by gut microbiota. Metagenome, transcriptome, and metabolome analyses have revealed that sPLA2-IIA deficiency alters the gut microbiota, accompanied by notable changes in the intestinal expression of genes related to immunity and metabolism, as well as in the levels of various blood metabolites and fecal bacterial lipids, suggesting that sPLA2-IIA contributes to shaping of the gut microbiota. The skin phenotypes in Pla2g2a-/- mice are lost (a) when they are cohoused with littermate WT mice, resulting in the mixing of the microbiota between the genotypes, or (b) when they are housed in a more stringent pathogen-free facility, where Pla2g2a expression in WT mice is low and the gut microbial compositions in both genotypes are nearly identical. Thus, our results highlight a potentially new aspect of sPLA2-IIA as a modulator of gut microbiota, perturbation of which affects distal skin responses.
Hideaki Morishita, Yuki Kanda, Takeshi Kaizuka, Haruka Chino, Kazuki Nakao, Yoshimi Miki, Yoshitaka Taketomi, Lin Jun Guan, Makoto Murakami, Atsu Aiba and Noboru Mizushima : Autophagy Is Required for Maturation of Surfactant-Containing Lamellar Bodies in the Lung and Swim Bladder, Cell Reports, 33, 10, 108477, 2020.
(Summary)
Autophagy is an intracellular degradation system, but its physiological functions in vertebrates are not yet fully understood. Here, we show that autophagy is required for inflation of air-filled organs: zebrafish swim bladder and mouse lung. In wild-type zebrafish swim bladder and mouse lung type II pulmonary epithelial cells, autophagosomes are formed and frequently fuse with lamellar bodies. The lamellar body is a lysosome-related organelle that stores a phospholipid-containing surfactant complex that lines the air-liquid interface and reduces surface tension. We find that autophagy is critical for maturation of the lamellar body. Accordingly, atg-deficient zebrafish fail to maintain their position in the water, and type-II-pneumocyte-specific Fip200-deficient mice show neonatal lethality with respiratory failure. Autophagy suppression does not affect synthesis of the surfactant phospholipid, suggesting that autophagy supplies lipids and membranes to lamellar bodies. These results demonstrate an evolutionarily conserved role of autophagy in lamellar body maturation.
Kazuhiro Watanabe, Yoshitaka Taketomi, Yoshimi Miki, Kiyotaka Kugiyama and Makoto Murakami : Group V secreted phospholipase A2plays a protective role against aortic dissection, The Journal of Biological Chemistry, 295, 30, 10092-10111, 2020.
(Summary)
Aortic dissection is a life-threatening aortopathy involving separation of the aortic wall, whose underlying mechanisms are still incompletely understood. Epidemiological evidence suggests that unsaturated fatty acids improve cardiovascular health. Here, using quantitative RT-PCR, histological analyses, magnetic cell sorting and flow cytometry assays, and MS-based lipidomics, we show that the activity of a lipid-metabolizing enzyme, secreted phospholipase A2 group V (sPLA2-V), protects against aortic dissection by endogenously mobilizing vasoprotective lipids. Global and endothelial cell-specific sPLA2-V-deficient mice frequently developed aortic dissection shortly after infusion of angiotensin II (AT-II). We observed that in the AT-II-treated aorta, endothelial sPLA2-V mobilized oleic and linoleic acids, which attenuated endoplasmic reticulum stress, increased the expression of lysyl oxidase, and thereby stabilized the extracellular matrix in the aorta. Of note, dietary supplementation with oleic or linoleic acid reversed the increased susceptibility of sPLA2-V-deficient mice to aortic dissection. These findings reveal an unexplored functional link between sPLA2-driven phospholipid metabolism and aortic stability, possibly contributing to the development of improved diagnostic and/or therapeutic strategies for preventing aortic dissection.
Hiroyasu Sato, Yoshitaka Taketomi, Yoshimi Miki, Remi Murase, Kei Yamamoto and Makoto Murakami : Secreted Phospholipase PLA2G2D Contributes to Metabolic Health by Mobilizing ω3 Polyunsaturated Fatty Acids in WAT, Cell Reports, 31, 5, 107579, 2020.
(Summary)
Polyunsaturated fatty acids (PUFAs) confer health benefits by preventing inflammation and obesity and by increasing thermogenesis in brown and beige adipocytes. As well as being supplied exogenously as nutrients, PUFAs are largely stored in membrane glycerophospholipids and released by phospholipase A2s (PLA2s). However, the molecular identity of the PLA2 subtype(s) that supplies endogenous PUFAs for metabolic homeostasis remains unclear. Here we show that PLA2G2D, a secreted PLA2 isoform, is constitutively expressed in M2-type macrophages in white adipose tissue (WAT) and shows a reciprocal correlation with obesity. Studies using global and macrophage-specific Pla2g2d-deficient mice reveal that PLA2G2D increases energy expenditure and thermogenesis by facilitating adipocyte browning, thereby ameliorating diet-induced obesity, insulin resistance, and WAT inflammation. Mechanistically, PLA2G2D constitutively supplies a pool of PUFAs, ω3 in particular, in WAT. Thus, our present findings underscore the contribution of the macrophage-driven PLA2G2D-ω3 PUFA axis to metabolic health.
5-lipoxygenase is a key enzyme in the synthesis of leukotrienes from arachidonic acid. The produced leukotrienes are involved in inflammatory diseases including psoriasis, asthma, and atherosclerosis. A suitable 5-lipoxygenase inhibitor might be useful for preventing and improving the symptoms of leukotriene-related inflammatory diseases. Here, we investigate the mechanism underlying the anti-inflammatory effect of a proanthocyanidin found in red-kerneled rice. Red-kerneled rice proanthocyanidin exhibited potent mixed noncompetitive inhibition of human and rat 5-lipoxygenases, with an IC50 values of 15.1 μM against human enzyme, and 7.0 μM against rat enzyme, respectively. This compound decreased leukotriene B4 production in rat basophilic leukemia-2H3 cells. In imiquimod-induced psoriasis-like mouse skin, topical application of the proanthocyanidin suppressed hyperplasia, decreased inflammatory cell infiltration, and down-regulated expression of the psoriasis-associated genes Il17a, Il22, S100a9, and Krt1. Lipid metabolome analysis by electrospray ionization mass spectrometry showed that red-kerneled rice proanthocyanidin treatment of psoriasis-like mouse skin dose-dependently decreased the production of leukotriene B4 but no other arachidonate metabolites. Red-kerneled rice proanthocyanidin inhibits 5-lipoxygenase, resulting in a decrease in leukotriene B4 production and psoriasis-like mouse skin inflammation. These results suggest that this proanthocyanidin may be therapeutically effective for treating leukotriene-related diseases.
Akio Mori, Taku Hatano, Tsuyoshi Inoshita, Kahori Shiba-Fukushima, Takahiro Koinuma, Hongrui Meng, Shin-ichiro Kubo, Spencer Spratt, Changxu Cui, Chikara Yamashita, Yoshimi Miki, Kei Yamamoto, Tetsuya Hirabayashi, Makoto Murakami, Yoshikazu Yakahashi, Hideo Shindou, Takashi Nonaka, Masato Hasegawa, Ayami Okuzumi, Yuzuru Imai and Nobutaka Hattori : Parkinsons disease-associated iPLA2-VIA/PLA2G6 regulates neuronal functions and α-synuclein stability through membrane remodeling, Proceedings of the National Academy of Sciences of the United States of America, 116, 41, 20689-20699, 2019.
(Summary)
Mutations in the gene are responsible for -linked Parkinson's disease (PD) with α-synucleinopathy. However, it is unclear how mutations lead to α-synuclein (α-Syn) aggregation and dopaminergic (DA) neurodegeneration. Here, we report that -deficient exhibits defects in neurotransmission during early developmental stages and progressive cell loss throughout the brain, including degeneration of the DA neurons. Lipid analysis of brain tissues reveals that the acyl-chain length of phospholipids is shortened by loss, which causes endoplasmic reticulum (ER) stress through membrane lipid disequilibrium. The introduction of wild-type human iPLA2-VIA or the mitochondria-ER contact site-resident protein C19orf12 in -deficient flies rescues the phenotypes associated with altered lipid composition, ER stress, and DA neurodegeneration, whereas the introduction of a disease-associated missense mutant, A80T, fails to suppress these phenotypes. The acceleration of α-Syn aggregation by loss is suppressed by the administration of linoleic acid, correcting the brain lipid composition. Our findings suggest that membrane remodeling by iPLA2-VIA is required for the survival of DA neurons and α-Syn stability.
Remi Murase, Yoshitaka Taketomi, Yoshimi Miki, Yasumasa Nishito, Moe Saito, Kiyoko Fukami, Kei Yamamoto and Makoto Murakami : Group III phospholipase A2 promotes colitis and colorectal cancer, Scientific Reports, 7, 1, 12261, 2017.
(Summary)
Lipid mediators play pivotal roles in colorectal cancer and colitis, but only a limited member of the phospholipase A2 (PLA2) subtypes, which lie upstream of various lipid mediators, have been implicated in the positive or negative regulation of these diseases. Clinical and biochemical evidence suggests that secreted PLA2 group III (sPLA2-III) is associated with colorectal cancer, although its precise role remains obscure. Here we have found that sPLA2-III-null (Pla2g3 -/-) mice are highly resistant to colon carcinogenesis. Furthermore, Pla2g3 -/- mice are less susceptible to dextran sulfate-induced colitis, implying that the amelioration of colonic inflammation by sPLA2-III ablation may underlie the protective effect against colon cancer. Lipidomics analysis of the colon revealed significant reduction of pro-inflammatory/pro-tumorigenic lysophosholipids as well as unusual steady-state elevation of colon-protective fatty acids and their oxygenated metabolites in Pla2g3 -/- mice. Overall, our results establish a role of sPLA2-III in the promotion of colorectal inflammation and cancer, expand our understanding of the divergent roles of multiple PLA2 enzymes in the gastrointestinal tract, and point to sPLA2-III as a novel druggable target for colorectal diseases.
Atsushi Irie, Kei Yamamoto, Yoshimi Miki and Makoto Murakami : Phosphatidylethanolamine dynamics are required for osteoclast fusion, Scientific Reports, 7, 46715, 2017.
(Summary)
Osteoclasts, responsible for bone resorption, are multinucleated cells formed by cell-cell fusion of mononuclear pre-osteoclasts. Although osteoclast fusion is a pivotal step for osteoclastogenesis, little is known about the mechanism involved. To clarify the underlying process, we investigated dynamics of membrane phospholipids during osteoclastogenesis in vitro. We found that the cellular content of phospholipids, phosphatidylethanolamine (PE) in particular, was increased during osteoclast differentiation. Furthermore, PE was greatly increased in the outer leaflet of the plasma membrane bilayer during osteoclastogenesis, being concentrated in filopodia involved in cell-cell fusion. Immobilisation of the cell surface PE blocked osteoclast fusion, revealing the importance of PE abundance and distribution. To identify the molecules responsible for these PE dynamics, we screened a wide array of lipid-related genes by quantitative PCR and shRNA-mediated knockdown. Among them, a PE-biosynthetic enzyme, acyl-CoA:lysophosphatidylethanolamine acyltransferase 2 (LPEAT2), and two ATP-binding cassette (ABC) transporters, ABCB4 and ABCG1, were markedly increased during osteoclastogenesis, and their knockdown in pre-osteoclasts led to reduction in PE exposure on the cell surface and subsequent osteoclast fusion. These findings demonstrate that the PE dynamics play an essential role in osteoclast fusion, in which LPEAT2, ABCB4 and ABCG1 are key players for PE biosynthesis and redistribution.
(Keyword)
ATP Binding Cassette Transporter, Subfamily B / ATP Binding Cassette Transporter, Subfamily G, Member 1 / Acyltransferases / Animals / Bone Resorption / Cell Fusion / Cell Membrane / Cells, Cultured / Mice, Inbred C57BL / Osteoclasts / Osteogenesis / Phosphatidylethanolamines
Kei Yamamoto, Yoshimi Miki, Hiroyasu Sato, Yasumasa Nishito, H. Michael Gelb, Yoshitaka Taketomi and Makoto Murakami : Expression and function of group IIE phospholipase A2 in mouse skin, The Journal of Biological Chemistry, 291, 30, 15602-15613, 2016.
(Summary)
Recent studies using knock-out mice for various secreted phospholipase A2 (sPLA2) isoforms have revealed their non-redundant roles in diverse biological events. In the skin, group IIF sPLA2 (sPLA2-IIF), an "epidermal sPLA2" expressed in the suprabasal keratinocytes, plays a fundamental role in epidermal-hyperplasic diseases such as psoriasis and skin cancer. In this study, we found that group IIE sPLA2 (sPLA2-IIE) was expressed abundantly in hair follicles and to a lesser extent in basal epidermal keratinocytes in mouse skin. Mice lacking sPLA2-IIE exhibited skin abnormalities distinct from those in mice lacking sPLA2-IIF, with perturbation of hair follicle ultrastructure, modest changes in the steady-state expression of a subset of skin genes, and no changes in the features of psoriasis or contact dermatitis. Lipidomics analysis revealed that sPLA2-IIE and -IIF were coupled with distinct lipid pathways in the skin. Overall, two skin sPLA2s, hair follicular sPLA2-IIE and epidermal sPLA2-IIF, play non-redundant roles in distinct compartments of mouse skin, underscoring the functional diversity of multiple sPLA2s in the coordinated regulation of skin homeostasis and diseases.
Yoshimi Miki, Yuh Kidoguchi, Mariko Sato, Yoshitaka Taketomi, Choji Taya, Kazuaki Muramatsu, H. Michael Gelb, Kei Yamamoto and Makoto Murakami : Dual roles of group IID phospholipase A2 in inflammation and cancer, The Journal of Biological Chemistry, 291, 30, 15588-15601, 2016.
(Summary)
Phospholipase A2 enzymes have long been implicated in the promotion of inflammation by mobilizing pro-inflammatory lipid mediators, yet recent evidence suggests that they also contribute to anti-inflammatory or pro-resolving programs. Group IID-secreted phospholipase A2 (sPLA2-IID) is abundantly expressed in dendritic cells in lymphoid tissues and resolves the Th1 immune response by controlling the steady-state levels of anti-inflammatory lipids such as docosahexaenoic acid and its metabolites. Here, we show that psoriasis and contact dermatitis were exacerbated in Pla2g2d-null mice, whereas they were ameliorated in Pla2g2d-overexpressing transgenic mice, relative to littermate wild-type mice. These phenotypes were associated with concomitant alterations in the tissue levels of ω3 polyunsaturated fatty acid (PUFA) metabolites, which had the capacity to reduce the expression of pro-inflammatory and Th1/Th17-type cytokines in dendritic cells or lymph node cells. In the context of cancer, however, Pla2g2d deficiency resulted in marked attenuation of skin carcinogenesis, likely because of the augmented anti-tumor immunity. Altogether, these results underscore a general role of sPLA2-IID as an immunosuppressive sPLA2 that allows the microenvironmental lipid balance toward an anti-inflammatory state, exerting beneficial or detrimental impact depending upon distinct pathophysiological contexts in inflammation and cancer.
Kei Yamamoto, Yoshimi Miki, Mariko Sato, Yoshitaka Taketomi, Yasumasa Nishito, Choji Taya, Kazuaki Muramatsu, Kazutaka Ikeda, Hiroki Nakanishi, Ryo Taguchi, Naotomo Kambe, Kenji Kabashima, Gérard Lambeau, Michael H. Gelb and Makoto Murakami : The role of group IIF secreted phospholipase A2 in epidermal homeostasis and hyperplasia., The Journal of Experimental Medicine, 212, 11, 1901-1919, 2015.
(Summary)
Epidermal lipids are important for skin homeostasis. However, the entire picture of the roles of lipids, particularly nonceramide lipid species, in epidermal biology still remains obscure. Here, we report that PLA2G2F, a functionally orphan-secreted phospholipase A2 expressed in the suprabasal epidermis, regulates skin homeostasis and hyperplasic disorders. Pla2g2f(-/-) mice had a fragile stratum corneum and were strikingly protected from psoriasis, contact dermatitis, and skin cancer. Conversely, Pla2g2f-overexpressing transgenic mice displayed psoriasis-like epidermal hyperplasia. Primary keratinocytes from Pla2g2f(-) (/-) mice showed defective differentiation and activation. PLA2G2F was induced by calcium or IL-22 in keratinocytes and preferentially hydrolyzed ethanolamine plasmalogen-bearing docosahexaenoic acid secreted from keratinocytes to give rise to unique bioactive lipids (i.e., protectin D1 and 9S-hydroxyoctadecadienoic acid) that were distinct from canonical arachidonate metabolites (prostaglandins and leukotrienes). Ethanolamine lysoplasmalogen, a PLA2G2F-derived marker product, rescued defective activation of Pla2g2f(-/-) keratinocytes both in vitro and in vivo. Our results highlight PLA2G2F as a previously unrecognized regulator of skin pathophysiology and point to this enzyme as a novel drug target for epidermal-hyperplasic diseases.
Rahul Vijay, Xiaoyang Hua, K. David Meyerholz, Yoshimi Miki, Kei Yamamoto, Michael Gelb, Makoto Murakami and Stanley Perlman : Critical role of phospholipase A2 group IID in age-related susceptibility to severe acute respiratory syndrome-CoV infection, The Journal of Experimental Medicine, 212, 11, 1851-1868, 2015.
(Summary)
Oxidative stress and chronic low-grade inflammation in the lungs are associated with aging and may contribute to age-related immune dysfunction. To maintain lung homeostasis, chronic inflammation is countered by enhanced expression of proresolving/antiinflammatory factors. Here, we show that age-dependent increases of one such factor in the lungs, a phospholipase A2 (PLA2) group IID (PLA2G2D) with antiinflammatory properties, contributed to worse outcomes in mice infected with severe acute respiratory syndrome-coronavirus (SARS-CoV). Strikingly, infection of mice lacking PLA2G2D expression (Pla2g2d(-/-) mice) converted a uniformly lethal infection to a nonlethal one (>80% survival), subsequent to development of enhanced respiratory DC migration to the draining lymph nodes, augmented antivirus T cell responses, and diminished lung damage. We also observed similar effects in influenza A virus-infected middle-aged Pla2g2d(-/-) mice. Furthermore, oxidative stress, probably via lipid peroxidation, was found to induce PLA2G2D expression in mice and in human monocyte-derived macrophages. Thus, our results suggest that directed inhibition of a single inducible phospholipase, PLA2G2D, in the lungs of older patients with severe respiratory infections is potentially an attractive therapeutic intervention to restore immune function.
Hiroyasu Sato, Yoshitaka Taketomi, Ayako Ushida, Yuki Isogai, Takumi Kojima, Tetsuya Hirabayashi, Yoshimi Miki, Kei Yamamoto, Yasumasa Nishito, Tetsuyuki Kobayashi, Kazutaka Ikeda, Ryo Taguchi, Shuntaro Hara, Satoshi Ida, Yuji Miyamoto, Masayuki Watanabe, Hideo Baba, Keishi Miyata, Yuichi Oike, H. Michael Gelb and Makoto Murakami : The adipocyte-inducible secreted phospholipases PLA2G5 and PLA2G2E play distinct roles in obesity, Cell Metabolism, 20, 1, 119-132, 2014.
(Summary)
Metabolic disorders, including obesity and insulin resistance, have their basis in dysregulated lipid metabolism and low-grade inflammation. In a microarray search of unique lipase-related genes whose expressions are associated with obesity, we found that two secreted phospholipase A2s (sPLA2s), PLA2G5 and PLA2G2E, were robustly induced in adipocytes of obese mice. Analyses of Pla2g5(-/-) and Pla2g2e(-/-) mice revealed distinct roles of these sPLA2s in diet-induced obesity. PLA2G5 hydrolyzed phosphatidylcholine in fat-overladen low-density lipoprotein to release unsaturated fatty acids, which prevented palmitate-induced M1 macrophage polarization. As such, PLA2G5 tipped the immune balance toward an M2 state, thereby counteracting adipose tissue inflammation, insulin resistance, hyperlipidemia, and obesity. PLA2G2E altered minor lipoprotein phospholipids, phosphatidylserine and phosphatidylethanolamine, and moderately facilitated lipid accumulation in adipose tissue and liver. Collectively, the identification of "metabolic sPLA2s" adds this gene family to a growing list of lipolytic enzymes that act as metabolic coordinators.
(Keyword)
Adipose Tissue, White / Animals / Cells, Cultured / Diet, High-Fat / Female / Glucose Tolerance Test / Group II Phospholipases A2 / Group V Phospholipases A2 / Humans / Inflammation / Insulin / Leptin / Lipoproteins / Liver / Macrophages / Mice / Mice, Inbred C57BL / Mice, Knockout / Mice, Obese / Obesity / Proto-Oncogene Proteins c-akt / RNA, Messenger / Time Factors
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, M. James Bollinger, Shuntaro Hara, H. Michael Gelb and Makoto Murakami : Lymphoid tissue phospholipase A2 group IID resolves contact hypersensitivity by driving antiinflammatory lipid mediators, The Journal of Experimental Medicine, 210, 6, 1217-1234, 2013.
(Summary)
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.
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 and Makoto Murakamia : Hair follicular expression and function of group X secreted phospholipase A2 in mouse skin, The Journal of Biological Chemistry, 286, 13, 11616-11631, 2011.
(Summary)
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.
Although the secreted phospholipase A(2) (sPLA(2)) family has been generally thought to participate in pathologic events such as inflammation and atherosclerosis, relatively high and constitutive expression of group X sPLA(2) (sPLA(2)-X) in restricted sites such as reproductive organs, the gastrointestinal tract, and peripheral neurons raises a question as to the roles played by this enzyme in the physiology of reproduction, digestion, and the nervous system. Herein we used mice with gene disruption or transgenic overexpression of sPLA(2)-X to clarify the homeostatic functions of this enzyme at these locations. Our results suggest that sPLA(2)-X regulates 1) the fertility of spermatozoa, not oocytes, beyond the step of flagellar motility, 2) gastrointestinal phospholipid digestion, perturbation of which is eventually linked to delayed onset of a lean phenotype with reduced adiposity, decreased plasma leptin, and improved muscle insulin tolerance, and 3) neuritogenesis of dorsal root ganglia and the duration of peripheral pain nociception. Thus, besides its inflammatory action proposed previously, sPLA(2)-X participates in physiologic processes including male fertility, gastrointestinal phospholipid digestion linked to adiposity, and neuronal outgrowth and sensing.
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 and Makoto Murakami : Group III secreted phospholipase A2 regulates epididymal sperm maturation and fertility in mice, The Journal of Clinical Investigation, 120, 5, 1400-1414, 2010.
(Summary)
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.
Yoshimi Miki, Tomohito Amano, Niki Hirabayashi, Asuka Tamai, Akira Shigenaga, 村上 誠 and Kei Yamamoto : アセタール型リゾプラズマローゲンは創傷治癒を促進する, Proceedings of the Japanese Conference on the Biochemistry of Lipids, 66, 161-163, 2024.
Niki Hirabayashi, Tomohito Amano, Yoshimi Miki, 武市 拓也, 秋山 真志, 村上 誠 and Kei Yamamoto : sPLA2-IIF/P-LPE経路はアトピー性皮膚炎を制御する, Proceedings of the Japanese Conference on the Biochemistry of Lipids, 65, 118-119, 2023.
4.
Akari Fukuta, 重永 章, Haruna Taniguchi, Honami Inubushi, Tomohito Amano, Yoshimi Miki, 村上 誠 and Kei Yamamoto : sPLA2-IIFの二次産物であるアセタール型リゾプラズマローゲンは創傷治癒を改善する, Proceedings of the Japanese Conference on the Biochemistry of Lipids, 64, 267-269, 2022.
5.
長崎 祐樹, 川井 恵梨佳, 丸岡 紗也, 大角 美穂, 津嘉山 泉, 川上 祐生, 高橋 吉孝, 岡崎 愉加, Yoshimi Miki, Kei Yamamoto, 村上 誠 and 山本 登志子 : ヒトとウシの乳汁中脂質プロファイル比較, Proceedings of the Japanese Conference on the Biochemistry of Lipids, 63, 142-143, 2021.
6.
Kei Yamamoto, Haruka Hakoi, Yoshimi Miki and 村上 誠 : IIF型分泌性ホスホリパーゼA2/リゾプラズマローゲン経路は表皮肥厚性疾患の新規創薬ターゲットである, Proceedings of the Japanese Conference on the Biochemistry of Lipids, 61, 57-58, 2019.
7.
戸田 圭祐, 津嘉山 泉, 長崎 祐樹, 爲延 麻子, 鴻池 優佳, 我如古 菜月, 伊東 秀之, 川上 祐生, 高橋 吉孝, Yoshimi Miki, Kei Yamamoto, 村上 誠 and 山本 登志子 : 赤米由来プロアントシアニジンによる5-リポキシゲナーゼ阻害と乾癬予防効果, Proceedings of the Japanese Conference on the Biochemistry of Lipids, 61, 74-75, 2019.
8.
入江 敦, Kei Yamamoto, Yoshimi Miki, 武富 芳隆 and 村上 誠 : 破骨細胞における膜リン脂質の代謝動態:PEの合成・輸送・分解と膜融合, Proceedings of the Japanese Conference on the Biochemistry of Lipids, 59, 79-80, 2017.
9.
Yoshimi Miki, 城戸 口優, Kei Yamamoto and 村上 誠 : 炎症および癌病態におけるIID型sPLA2の二面的役割, Proceedings of the Japanese Conference on the Biochemistry of Lipids, 58, 114-116, 2016.
10.
武富 芳隆, 砂川 アンナ, 入江 敦, Yoshimi Miki, Kei Yamamoto, 佐藤 弘泰, 小林 哲幸 and 村上 誠 : マスト細胞を制御する第二のAnaphylatic sPLA2の同定, Proceedings of the Japanese Conference on the Biochemistry of Lipids, 58, 119-121, 2016.
11.
武富 芳隆, 砂川 アンナ, 入江 敦, Yoshimi Miki, Kei Yamamoto, 佐藤 弘泰, 小林 哲幸 and 村上 誠 : マスト細胞を制御する第二のAnaphylatic sPLA2の同定, Proceedings of the Japanese Conference on the Biochemistry of Lipids, 58, 119-121, 2016.
12.
Kei Yamamoto, Yoshimi Miki and 村上 誠 : IIF型分泌性ホスホリパーゼA2により産生されるアルケニル型リゾホスファチジルエタノールアミンは表皮肥厚性疾患のバイオマーカーである, Proceedings of the Japanese Conference on the Biochemistry of Lipids, 57, 136-137, 2015.
Review, Commentary:
1.
Yoshitaka Taketomi, Yoshimi Miki and Makoto Murakami : Old but New: Group IIA Phospholipase A2 as a Modulator of Gut Microbiota, Metabolites, 12, 4, Apr. 2022.
(Keyword)
gut microbiota / lipid metabolism / metabolomics / phospholipase A2
Makoto Murakami, Yoshimi Miki, Hiroyasu Sato, Remi Murase, Yoshitaka Taketomi and Kei Yamamoto : Group IID, IIE, IIF and III secreted phospholipase A 2 s, Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids, 1864, 6, 803-818, Aug. 2018.
(Summary)
Among the 11 members of the secreted phospholipase A2 (sPLA2) family, group IID, IIE, IIF and III sPLA2s (sPLA2-IID, -IIE, -IIF and -III, respectively) are "new" isoforms in the history of sPLA2 research. Relative to the better characterized sPLA2s (sPLA2-IB, -IIA, -V and -X), the enzymatic properties, distributions, and functions of these "new" sPLA2s have remained obscure until recently. Our current studies using knockout and transgenic mice for a nearly full set of sPLA2s, in combination with comprehensive lipidomics, have revealed unique and distinct roles of these "new" sPLA2s in specific biological events. Thus, sPLA2-IID is involved in immune suppression, sPLA2-IIE in metabolic regulation and hair follicle homeostasis, sPLA2-IIF in epidermal hyperplasia, and sPLA2-III in male reproduction, anaphylaxis, colonic diseases, and possibly atherosclerosis. In this article, we overview current understanding of the properties and functions of these sPLA2s and their underlying lipid pathways in vivo.
(Keyword)
Knockout mice / Lipid-metabolic pathways / Lipidomics / Pathophysiological function / Secreted phospholipase A 2 / Transgenic mice
Makoto Murakami, Hiroyasu Sato, Yoshimi Miki, Kei Yamamoto and Yoshitaka Taketomi : A new era of secreted phospholipase A2, Journal of Lipid Research, 56, 7, 1248-1261, Mar. 2015.
(Summary)
Among more than 30 members of the phospholipase A2 (PLA2) superfamily, secreted PLA2 (sPLA2) enzymes represent the largest family, being Ca(2+)-dependent low-molecular-weight enzymes with a His-Asp catalytic dyad. Individual sPLA2s exhibit unique tissue and cellular distributions and enzymatic properties, suggesting their distinct biological roles. Recent studies using transgenic and knockout mice for nearly a full set of sPLA2 subtypes, in combination with sophisticated lipidomics as well as biochemical and cell biological studies, have revealed distinct contributions of individual sPLA2s to various pathophysiological events, including production of pro- and anti-inflammatory lipid mediators, regulation of membrane remodeling, degradation of foreign phospholipids in microbes or food, or modification of extracellular noncellular lipid components. In this review, we highlight the current understanding of the in vivo functions of sPLA2s and the underlying lipid pathways as revealed by a series of studies over the last decade.
Makoto Murakami, Yoshitaka Taketomi, Yoshimi Miki, Hiroyasu Sato, Kei Yamamoto and Gérard Lambeau : Emerging roles of secreted phospholipase A2 enzymes: The 3rd edition, Biochimie, 107, Part A, 105-113, Sep. 2014.
(Summary)
Within the phospholipase A2 (PLA2) superfamily, secreted PLA2 (sPLA2) enzymes comprise the largest family that contains 11 to 12 mammalian isoforms with a conserved His-Asp catalytic dyad. Individual sPLA2s exhibit unique tissue and cellular localizations and specific enzymatic properties, suggesting distinct biological roles. Individual sPLA2s are involved in diverse biological events through lipid mediator-dependent or -independent processes and act redundantly or non-redundantly in a given microenvironment. In the past few years, new biological aspects of sPLA2s have been clarified using their transgenic and knockout mouse lines in combination with mass spectrometric lipidomics to unveil their target substrates and products in vivo. In the 3rd edition of this review series, we highlight the newest understanding of the in vivo functions of sPLA2s in pathophysiological conditions in the context of immunity and metabolism. We will also describe the latest knowledge on PLA2R1, the best known sPLA2 receptor, which may serve either as a clearance or signaling receptor for sPLA2 or may even act independently of sPLA2 function.
Makoto Murakami, Yoshitaka Taketomi, Yoshimi Miki, Hiroyasu Sato, Tetsuya Hirabayashi and Kei Yamamoto : Recent progress in phospholipase A2 research: From cells to animals to humans, Progress in Lipid Research, 50, 2, 152-192, Dec. 2010.
(Summary)
Mammalian genomes encode genes for more than 30 phospholipase A2s (PLA2s) or related enzymes, which are subdivided into several classes including low-molecular-weight secreted PLA2s (sPLA2s), Ca²+-dependent cytosolic PLA2s (cPLA2s), Ca²+-independent PLA2s (iPLA2s), platelet-activating factor acetylhydrolases (PAF-AHs), lysosomal PLA2s, and a recently identified adipose-specific PLA. Of these, the intracellular cPLA2 and iPLA2 families and the extracellular sPLA2 family are recognized as the "big three". From a general viewpoint, cPLA2α (the prototypic cPLA2 plays a major role in the initiation of arachidonic acid metabolism, the iPLA2 family contributes to membrane homeostasis and energy metabolism, and the sPLA2 family affects various biological events by modulating the extracellular phospholipid milieus. The cPLA2 family evolved along with eicosanoid receptors when vertebrates first appeared, whereas the diverse branching of the iPLA2 and sPLA2 families during earlier eukaryote development suggests that they play fundamental roles in life-related processes. During the past decade, data concerning the unexplored roles of various PLA2 enzymes in pathophysiology have emerged on the basis of studies using knockout and transgenic mice, the use of specific inhibitors, and information obtained from analysis of human diseases caused by mutations in PLA2 genes. This review focuses on current understanding of the emerging biological functions of PLA2s and related enzymes.
Yoshimi Miki, Niki Hirabayashi, Asuka Tamai, Akira Shigenaga, Makoto Murakami and Kei Yamamoto : Novel acetal-type lysoplasmalogen, a secondary product of group IIF phospholipase A2, promotes skin wound healing, The 64th International Conference on the Bioscience of Lipids (ICBL2024), Taipei, Oct. 2024.
2.
Kei Yamamoto, Niki Hirabayashi, Makoto Murakami and Yoshimi Miki : Role of the group IIF phospholipase A2/lysoplasmalogen pathway in atopic dermatitis, The 64th International Conference on the Bioscience of Lipids (ICBL2024), Taipei, Oct. 2024.
3.
Kei Yamamoto, Haruka Hakoi, Yoshimi Miki and Makoto Murakami : Group IIF phospholipase A2/lysophosplasmalogen axis is a novel drug target for epidermal-hyperplastic diseases., 60th International Conference on the Bioscience of Lipids., Tokyo, Jun. 2019.
4.
Kei Yamamoto, Yoshimi Miki, Mariko Sato and Makoto Murakami : Group IIF sPLA2 promotes skin carcinogenesis., 6th International conference on phospholipase A2 and lipid mediators., Tokyo, Feb. 2015.
5.
Yoshimi Miki, Kei Yamamoto and Makoto Murakami : Group IID sPLA2 resolves psoriasis by driving pro-resolving lipid mediators., 6th International conference on phospholipase A2 and lipid mediators., Tokyo, Feb. 2015.
6.
Kei Yamamoto, Yoshimi Miki, Yoshitaka Taketomi, Naotomo Kambe, Kenji Kabashima, Gerard Lambeau, Gelb H. Michael and Makoto Murakami : A unique lipid pathway driven by group IIF sPLA2 undelies epidermal-hyperplasic disorders., 6th International conference on phospholipase A2 and lipid mediators., Tokyo, Feb. 2015.
Kei Yamamoto, Yoshimi Miki and 村上 誠 : IIF型分泌性ホスホリパーゼA2により産生されるアルケニル型リゾホスファチジルエタノールアミンは表皮肥厚性疾患のバイオマーカーである, 第57回日本脂質生化学会, May 2015.
Et cetera, Workshop:
1.
Kokoro Matsura, Saki Nomura, Yoshimi Miki and Kei Yamamoto : Functional analysis of the orphan G protein-coupled receptor GPR87 in the skin, Tokushima-Chiayi international research forum, National Chiayi University, Feb. 2025.
2.
Karin Hamazume, Yoshimi Miki and Kei Yamamoto : Functional analysis of orphan GPCRs expressed in liver, Tokushima-Chiayi international research forum, National Chiayi University, Feb. 2025.
3.
Ayane Matsuchi, Kokoro Matsura, Yoshimi Miki and Kei Yamamoto : Lipidomics analysis of 3D skin culture model, Tokushima-Chiayi international research forum, National Chiayi University, Feb. 2025.
4.
Ayane Matsuchi, Kokoro Matsura, Yoshimi Miki and Kei Yamamoto : Lipidomics analysis of 3D skin culture model, Tokushima-Chiayi international research forum, National Chiayi University, Feb. 2025.
Elucidation of disease control mechanism by intestinal bacteria-host interactions through extracellular phospholipid metabolism (Project/Area Number: 19K07042 )
Extracellular lipid metabolism and skin diseases (Project/Area Number: 16K18882 )
Construction of foundation on the function of the immune suppressive sPLA2 and toward its drug discovery (Project/Area Number: 26860051 )
Nobel roles of sPLA2 that resolves inflammatory immune response (Project/Area Number: 24890296 )