17 results on '"Shin Morioka"'
Search Results
2. Elongation of Long-Chain Fatty Acids Is Crucial for Hematopoietic Stem Cell Engraftment and Leukemia Propagation
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Takayasu Kato, Yusuke Kiyoki, Sakura Kito, Takashi Matsuzaka, Shin Morioka, Junko Sasaki, Tatsuhiro Sakamoto, Hidekazu Nishikii, Naoshi Obara, Mamiko Sakata-Yanagimoto, Takehiko Sasaki, Hitoshi Shimano, and Shigeru Chiba
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Immunology ,Cell Biology ,Hematology ,Biochemistry - Published
- 2022
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3. Dynamic erectile responses of a novel penile organ model utilizing TPEM†
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Kentaro Suzuki, Makoto Tachibana, Atsushi Yoshiki, Shin Morioka, Daiki Hashimoto, Shunsuke Kuroki, Takehiko Sasaki, Tomoya Kataoka, Hisao Yamamura, Taiju Hyuga, Kota Fujimoto, Kazunori Kimura, Nobuhiko Yamamoto, Tsuyoshi Hirashima, and Gen Yamada
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Male ,Contraction (grammar) ,RHOA ,030232 urology & nephrology ,Erectile tissue ,Biology ,Models, Biological ,Nitric oxide ,Mice ,03 medical and health sciences ,chemistry.chemical_compound ,Organ Culture Techniques ,0302 clinical medicine ,Erectile Dysfunction ,medicine ,Animals ,Phenylephrine ,Cells, Cultured ,Mice, Inbred ICR ,Microscopy ,030219 obstetrics & reproductive medicine ,Penile Erection ,Cell Biology ,General Medicine ,medicine.disease ,Tadalafil ,Cell biology ,medicine.anatomical_structure ,Erectile dysfunction ,Reproductive Medicine ,chemistry ,biology.protein ,Penis ,medicine.drug - Abstract
Male penis is required to become erect during copulation. In the upper (dorsal) part of penis, the erectile tissue termed corpus cavernosum (CC) plays fundamental roles for erection by regulating the inner blood flow. When blood flows into the CC, the microvascular complex termed sinusoidal space is reported to expand during erection. A novel in vitro explant system to analyze the dynamic erectile responses during contraction/relaxation is established. The current data show regulatory contraction/relaxation processes induced by phenylephrine (PE) and nitric oxide (NO) donor mimicking dynamic erectile responses by in vitro CC explants. Two-photon excitation microscopy (TPEM) observation shows the synchronous movement of sinusoidal space and the entire CC. By taking advantages of the CC explant system, tadalafil (Cialis) was shown to increase sinusoidal relaxation. Histopathological changes have been generally reported associating with erection in several pathological conditions. Various stressed statuses have been suggested to occur in the erectile responses by previous studies. The current CC explant model enables to analyze such conditions through directly manipulating CC in the repeated contraction/relaxation processes. Expression of oxidative stress marker and contraction-related genes, Hypoxia-inducible factor 1-alpha (Hif1a), glutathione peroxidase 1 (Gpx1), Ras homolog family member A (RhoA), and Rho-associated protein kinase (Rock), was significantly increased in such repeated contraction/relaxation. Altogether, it is suggested that the system is valuable for analyzing structural changes and physiological responses to several regulators in the field of penile medicine.
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- 2021
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4. Establishment of mouse line showing inducible priapism-like phenotypes
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Daiki Hashimoto, Kota Fujimoto, Shin Morioka, Shinya Ayabe, Tomoya Kataoka, Ryutaro Fukumura, Yuko Ueda, Mizuki Kajimoto, Taiju Hyuga, Kentaro Suzuki, Isao Hara, Shinichi Asamura, Shigeharu Wakana, Atsushi Yoshiki, Yoichi Gondo, Masaru Tamura, Takehiko Sasaki, and Gen Yamada
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Reproductive Medicine ,Cell Biology - Abstract
Penile research is expected to reveal new targets for treatment and prevention of the complex mechanisms of its disorder including erectile dysfunction (ED). Thus, analyses of the molecular processes of penile ED and continuous erection as priapism are essential issues of reproductive medicine.By performing mouse N-ethyl-N-nitrosourea mutagenesis and exome sequencing, we established a novel mouse line displaying protruded genitalia phenotype (PGP; priapism-like phenotype) and identified a novelWe evaluated the role of phospholipids during erection for the first time and showed the mutants of inducible phenotypes of priapism. Moreover, quantitative analysis using LC-ESI/MS/MS revealed that the level of phosphatidylinositol (PI) was significantly lower in the mutant penile samples. These results imply that PI may contribute to penile erection by PITPα.Our findings suggest that the current mutant is a mouse model for priapism and abnormalities in PI signaling pathways through PITPα may lead to priapism providing an attractive novel therapeutic target in its treatment.
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- 2022
5. A mass spectrometric method for in-depth profiling of phosphoinositide regioisomers and their disease-associated regulation
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Shin Morioka, Hiroki Nakanishi, Toshiyoshi Yamamoto, Junya Hasegawa, Emi Tokuda, Tomoya Hikita, Tomoko Sakihara, Yuuki Kugii, Chitose Oneyama, Masakazu Yamazaki, Akira Suzuki, Junko Sasaki, and Takehiko Sasaki
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Male ,Class I Phosphatidylinositol 3-Kinases ,Science ,Gene Expression ,General Physics and Astronomy ,Exosomes ,Phosphatidylinositols ,Article ,Chromatography, Affinity ,Mass Spectrometry ,General Biochemistry, Genetics and Molecular Biology ,Mice ,Animals ,Humans ,Phospholipids ,Chromatography ,Multidisciplinary ,Epidermal Growth Factor ,PTEN Phosphohydrolase ,Prostate ,Prostatic Neoplasms ,Stereoisomerism ,General Chemistry ,HEK293 Cells ,Pyrimidines ,Lipidomics ,PC-3 Cells ,Metabolome ,Quinazolines ,lipids (amino acids, peptides, and proteins) ,HeLa Cells - Abstract
Phosphoinositides are a family of membrane lipids essential for many biological and pathological processes. Due to the existence of multiple phosphoinositide regioisomers and their low intracellular concentrations, profiling these lipids and linking a specific acyl variant to a change in biological state have been difficult. To enable the comprehensive analysis of phosphoinositide phosphorylation status and acyl chain identity, we develop PRMC-MS (Phosphoinositide Regioisomer Measurement by Chiral column chromatography and Mass Spectrometry). Using this method, we reveal a severe skewing in acyl chains in phosphoinositides in Pten-deficient prostate cancer tissues, extracellular mobilization of phosphoinositides upon expression of oncogenic PIK3CA, and a unique profile for exosomal phosphoinositides. Thus, our approach allows characterizing the dynamics of phosphoinositide acyl variants in intracellular and extracellular milieus., Different phosphoinositide isomers are involved in a variety of physiological and pathological processes. Here, the authors combine chiral column chromatography and mass spectrometry to measure phosphoinositide regioisomers, revealing their dynamic changes in intra- and extracellular cancer cell milieus.
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- 2022
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6. Polarized PtdIns(4,5)P 2 distribution mediated by a voltage-sensing phosphatase (VSP) regulates sperm motility
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Kenji Sakimura, Hiroki Nakanishi, Toyoshi Fujimoto, Haruhiko Miyata, Takafumi Kawai, Yasushi Okamura, Souhei Sakata, Shin Morioka, Junko Sasaki, Takehiko Sasaki, Masahiko Watanabe, and Masahito Ikawa
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Multidisciplinary ,Sperm flagellum ,urogenital system ,Capacitation ,Chemistry ,Phosphatase ,Distribution (pharmacology) ,Flagellum ,Sperm ,Sperm motility ,Ion channel ,Cell biology - Abstract
The voltage-sensing phosphatase (VSP) is a unique protein that shows voltage-dependent phosphoinositide phosphatase activity. Here we report that VSP is activated in mice sperm flagellum and generates a unique subcellular distribution pattern of PtdIns(4,5)P2 Sperm from VSP-/- mice show more Ca2+ influx upon capacitation than VSP+/- mice and abnormal circular motion. VSP-deficient sperm showed enhanced activity of Slo3, a PtdIns(4,5)P2-sensitive K+ channel, which selectively localizes to the principal piece of the flagellum and indirectly enhances Ca2+ influx. Most interestingly, freeze-fracture electron microscopy analysis indicates that normal sperm have much less PtdIns(4,5)P2 in the principal piece than in the midpiece of the flagellum, and this polarized PtdIns(4,5)P2 distribution disappeared in VSP-deficient sperm. Thus, VSP appears to optimize PtdIns(4,5)P2 distribution of the principal piece. These results imply that flagellar PtdIns(4,5)P2 distribution plays important roles in ion channel regulation as well as sperm motility.
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- 2019
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7. IMP dehydrogenase-2 drives aberrant nucleolar activity and promotes tumorigenesis in glioblastoma
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Ingrid Grummt, Sergey Mareninov, Holger Bierhoff, Paul S. Mischel, Hiroko Shimada, Lionel M.L. Chow, Nazanin Majd, Makoto Suematsu, Greg Lucey, Alexander Otto Eberhardt, Maya Asano, Yuki Ban, Kaori Kofuji, Eric P. Smith, Eric C. Holland, Noriaki Minami, Ralph J. DeBerardinis, Daisuke Yamashita, Ichiro Nakano, Kazutaka Sumita, Yoshiki Ikeda, Hirofumi Yoshino, Yuki Sugiura, Robert Bachoo, Lisa Lange, Akshiv Malhotra, Mika Sasaki, Risa Kawaguchi, Yonehiro Kanemura, Akiyoshi Hirayama, Annmarie Ramkissoon, William H. Yong, Masaru Mori, Trisha Wise-Draper, Tomoyoshi Soga, Dimitrios Anastasiou, Jumpei Terakawa, Juri Kiyokawa, Tatsuya Ozawa, Hiroaki Wakimoto, Kara Wolfe, Atsuo T. Sasaki, Nobuyuki Onishi, Satoshi Kofuji, Satsuki Ikeda, Craig Horbinski, Takiko Daikoku, Koichi Okumura, Mikako Warren, Shin Morioka, Hideyuki Saya, Naoya Sakamoto, Shuji Kitahara, Oltea Sampetrean, Wataru Yasui, Tomoyuki Mashimo, and Victoria L. Flanary
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Carcinogenesis ,Nucleolus ,IMP Dehydrogenase 2 ,Biology ,medicine.disease_cause ,Article ,03 medical and health sciences ,IMP Dehydrogenase ,0302 clinical medicine ,Downregulation and upregulation ,Transcription (biology) ,Cell Line, Tumor ,medicine ,Humans ,education ,Cell Proliferation ,030304 developmental biology ,chemistry.chemical_classification ,0303 health sciences ,education.field_of_study ,Cell growth ,Cell Biology ,Cell biology ,Cell Transformation, Neoplastic ,Enzyme ,chemistry ,RNA, Ribosomal ,030220 oncology & carcinogenesis ,Transfer RNA ,Glioblastoma ,Cell Nucleolus - Abstract
In many cancers, high proliferation rates correlate with elevation of rRNA and tRNA levels, and nucleolar hypertrophy. However, the underlying mechanisms linking increased nucleolar transcription and tumorigenesis are only minimally understood. Here we show that IMP dehydrogenase-2 (IMPDH2), the rate-limiting enzyme for de novo guanine nucleotide biosynthesis, is overexpressed in the highly lethal brain cancer glioblastoma. This leads to increased rRNA and tRNA synthesis, stabilization of the nucleolar GTP-binding protein nucleostemin, and enlarged, malformed nucleoli. Pharmacological or genetic inactivation of IMPDH2 in glioblastoma reverses these effects and inhibits cell proliferation, whereas untransformed glia cells are unaffected by similar IMPDH2 perturbations. Impairment of IMPDH2 activity triggers nucleolar stress and growth arrest of glioblastoma cells even in the absence of functional p53. Our results reveal that upregulation of IMPDH2 is a prerequisite for the occurance of aberrant nucleolar function and increased anabolic processes in glioblastoma, which constitutes a primary event in gliomagenesis.
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- 2019
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8. Lysophosphatidylinositol‐acyltransferase‐1 is involved in cytosolic Ca2+oscillations in macrophages
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Masaaki Ito, Hiroki Nakanishi, Kiyomi Nigorikawa, Junko Sasaki, Shinya Takemasu, Shunsuke Takasuga, Kaoru Hazeki, Shin Morioka, Isao Matsuoka, Takehiko Sasaki, Satoshi Kofuji, and Satoshi Eguchi
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0303 health sciences ,Inflammation ,Stimulation ,Cell Biology ,Biology ,Phospholipase ,Cell biology ,03 medical and health sciences ,Cytosol ,Immune system ,Genetics ,medicine ,Extracellular ,medicine.symptom ,Receptor ,Intracellular ,030304 developmental biology - Abstract
Lysophosphatidylinositol-acyltransferase-1 (LPIAT1) specifically catalyzes the transfer of arachidonoyl-CoA to lysophosphoinositides. LPIAT-/- mice have been shown to have severe defects in the brain and liver; however, the exact molecular mechanisms behind these conditions are not well understood. As immune cells have been implicated in liver inflammation based on disfunction of LPIAT1, we generated Raw264.7 macrophages deficient in LPIAT1, using shRNA and CRISPR/Cas9. The amount of C38:4 species in phosphoinositides, especially in PtdInsP2 , was remarkably decreased in these cells. Unlike in wild-type cells, LPIAT1-deficient cells showed prolonged oscillations of intracellular Ca2+ upon UDP stimulation, which is known to activate phospholipase Cβ through the Gq-coupled P2Y6 receptor, even in the absence of extracellular Ca2+ . It is speculated that the prolonged Ca2+ response may be relevant to the increased risk of liver inflammation induced by LPIAT1 disfunction.
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- 2019
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9. Polarized PtdIns(4,5)P
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Takafumi, Kawai, Haruhiko, Miyata, Hiroki, Nakanishi, Souhei, Sakata, Shin, Morioka, Junko, Sasaki, Masahiko, Watanabe, Kenji, Sakimura, Toyoshi, Fujimoto, Takehiko, Sasaki, Masahito, Ikawa, and Yasushi, Okamura
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Male ,Mice, Knockout ,Phosphatidylinositol 4,5-Diphosphate ,urogenital system ,Biological Sciences ,Spermatozoa ,Ion Channels ,Phosphoric Monoester Hydrolases ,Membrane Potentials ,Mice ,Flagella ,Sperm Tail ,Sperm Motility ,Animals ,Calcium Channels ,Large-Conductance Calcium-Activated Potassium Channels - Abstract
The voltage-sensing phosphatase (VSP) is a unique protein that shows voltage-dependent phosphoinositide phosphatase activity. Here we report that VSP is activated in mice sperm flagellum and generates a unique subcellular distribution pattern of PtdIns(4,5)P(2). Sperm from VSP(−/−) mice show more Ca(2+) influx upon capacitation than VSP(+/−) mice and abnormal circular motion. VSP-deficient sperm showed enhanced activity of Slo3, a PtdIns(4,5)P(2)-sensitive K(+) channel, which selectively localizes to the principal piece of the flagellum and indirectly enhances Ca(2+) influx. Most interestingly, freeze-fracture electron microscopy analysis indicates that normal sperm have much less PtdIns(4,5)P(2) in the principal piece than in the midpiece of the flagellum, and this polarized PtdIns(4,5)P(2) distribution disappeared in VSP-deficient sperm. Thus, VSP appears to optimize PtdIns(4,5)P(2) distribution of the principal piece. These results imply that flagellar PtdIns(4,5)P(2) distribution plays important roles in ion channel regulation as well as sperm motility.
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- 2019
10. Sac1 Phosphoinositide Phosphatase Regulates Foam Cell Formation by Modulating SR-A Expression in Macrophages
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Satoshi Kofuji, Takuma Matsumura, Shin Morioka, Hiromi Sakamoto, Kaoru Hazeki, Shunsuke Takasuga, and Kiyomi Nigorikawa
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0301 basic medicine ,Glycosylation ,Cell ,Phosphatase ,Pharmaceutical Science ,Protein degradation ,03 medical and health sciences ,chemistry.chemical_compound ,Mice ,0302 clinical medicine ,medicine ,Animals ,RNA, Messenger ,Scavenger receptor ,RNA, Small Interfering ,Foam cell ,Pharmacology ,Gene knockdown ,Membrane Proteins ,Scavenger Receptors, Class A ,General Medicine ,Transfection ,Cell biology ,Lipoproteins, LDL ,030104 developmental biology ,medicine.anatomical_structure ,RAW 264.7 Cells ,chemistry ,030220 oncology & carcinogenesis ,lipids (amino acids, peptides, and proteins) ,Phosphoinositide Phosphatases ,Foam Cells - Abstract
Macrophages endocytose modified low-density lipoproteins (LDL) vigorously via scavenger receptor A (SR-A) to become foam cells. In the present study, we found that Sac1, a member of the Sac family of phosphoinositide phosphatases, increases the protein level of SR-A and upregulates foam cell formation. Mouse macrophages (RAW264.7) were transfected with short hairpin RNAs (shRNAs) against Sac1. Sac1 knockdown decreased cell surface SR-A levels and impaired acetylated LDL-induced foam cell formation. Transfection of Sac1-knockdown cells with shRNA-resistant flag-Sac1 effectively rescued the expression of SR-A. Glycosylation of SR-A was largely attenuated by Sac1 knockdown, but neither mRNA expression nor protein degradation of SR-A were affected. These results suggest that Sac1 maintains SR-A protein levels by modulating SR-A glycosylation.
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- 2019
11. Lysophosphatidylinositol-acyltransferase-1 is involved in cytosolic Ca
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Shinya, Takemasu, Masaaki, Ito, Shin, Morioka, Kiyomi, Nigorikawa, Satoshi, Kofuji, Shunsuke, Takasuga, Satoshi, Eguchi, Hiroki, Nakanishi, Isao, Matsuoka, Junko, Sasaki, Takehiko, Sasaki, and Kaoru, Hazeki
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Mice ,RAW 264.7 Cells ,Animals ,Calcium Signaling ,Acyltransferases - Abstract
Lysophosphatidylinositol-acyltransferase-1 (LPIAT1) specifically catalyzes the transfer of arachidonoyl-CoA to lysophosphoinositides. LPIAT
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- 2019
12. Myeloid cell-specific inositol polyphosphate-4-phosphatase type I knockout mice impair bacteria clearance in a murine peritonitis model
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Junko Sasaki, Shin Morioka, Takehiko Sasaki, Kaoru Hazeki, Yoshihiro Kasuu, Osamu Hazeki, and Kiyomi Nigorikawa
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0301 basic medicine ,Immunology ,Peritonitis ,Biology ,Microbiology ,Proinflammatory cytokine ,Dephosphorylation ,Mice ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Phosphatidylinositol Phosphates ,Escherichia coli ,Animals ,Humans ,Inositol ,Phosphatidylinositol ,Lung ,Molecular Biology ,Protein kinase B ,Cells, Cultured ,Escherichia coli Infections ,PI3K/AKT/mTOR pathway ,Mice, Knockout ,Cell Biology ,Shock, Septic ,Molecular biology ,Phosphoric Monoester Hydrolases ,Mice, Inbred C57BL ,Disease Models, Animal ,030104 developmental biology ,Infectious Diseases ,chemistry ,Knockout mouse ,Macrophages, Peritoneal ,Cytokines ,Signal transduction ,Proto-Oncogene Proteins c-akt ,Signal Transduction ,030215 immunology - Abstract
Phosphatidylinositol 3-kinase (PI3K)/Akt signaling has been implicated in the anti-inflammatory response in a mouse model of endotoxemia and sepsis. The present study focused on the role of inositol polyphosphate-4-phosphatase type I (Inpp4a), which dephosphorylates PtdIns(3,4)P2 to PtdIns(3)P, in bacterial infections. We prepared myeloid cell-specific Inpp4a-conditional knockout mice. Macrophages from these mice showed increased Akt phosphorylation and reduced production of inflammatory cytokines in response to LPS or Escherichia coli in vitro. The Inpp4a knockout mice survived for a shorter time than wild type mice after i.p. infection with E. coli, with less production of inflammatory cytokines. Additionally, E. coli clearance from blood and lung was significantly impaired in the knockout mice. A likely mechanism is that the Inpp4a-catalyzed dephosphorylation of PtdIns(3,4)P2 down-regulates Akt pathways, which, in turn, increases the production of inflammatory mediators. This mechanism at least fits the decreased E. coli clearance and short survival in the Inpp4a knockout mice.
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- 2016
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13. TMEM55a localizes to macrophage phagosomes to down-regulate phagocytosis
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Yoshihiro Kasuu, Miho Yamada, Kiyomi Nigorikawa, Yoshimasa Tanaka, Satoshi Kofuji, Kaoru Hazeki, Shin Morioka, Shunsuke Takasuga, Takehiko Sasaki, Hiroki Nakanishi, and Eri Okada
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Phosphatidylinositol 4,5-Diphosphate ,0301 basic medicine ,Phagocytic cup ,Phagocytosis ,Phosphatase ,Vesicular Transport Proteins ,Biology ,Phosphatidylinositols ,Mice ,Phosphatidylinositol 3-Kinases ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Phagosomes ,Animals ,Macrophage ,Phosphatidylinositol ,Phagosome ,Macrophages ,Cell Membrane ,Cell Biology ,Transfection ,In vitro ,Cell biology ,Phosphotransferases (Alcohol Group Acceptor) ,RAW 264.7 Cells ,030104 developmental biology ,chemistry ,Phosphoinositide Phosphatases ,030217 neurology & neurosurgery ,Protein Binding - Abstract
TMEM55a (also known as PIP4P2) is an enzyme that dephosphorylates the phosphatidylinositol (PtdIns) PtdIns(4,5)P2 to form PtdIns(5)P in vitro However, the in vivo conversion of the polyphosphoinositide into PtdIns(5)P by the phosphatase has not yet been demonstrated, and the role of TMEM55a remains poorly understood. Here, we found that mouse macrophages (Raw264.7) deficient in TMEM55a showed an increased engulfment of large particles without affecting the phagocytosis of Escherichia coli Transfection of a bacterial phosphatase with similar substrate specificity to TMEM55a, namely IpgD, into Raw264.7 cells inhibited the engulfment of IgG-erythrocytes in a manner dependent on its phosphatase activity. In contrast, cells transfected with PIP4K2a, which catalyzes PtdIns(4,5)P2 production from PtdIns(5)P, increased phagocytosis. Fluorescent TMEM55a transfected into Raw264.7 cells was found to mostly localize to the phagosome. The accumulation of PtdIns(4,5)P2, PtdIns(3,4,5)P3 and F-actin on the phagocytic cup was increased in TMEM55a-deficient cells, as monitored by live-cell imaging. Phagosomal PtdIns(5)P was decreased in the knockdown cells, but the augmentation of phagocytosis in these cells was unaffected by the exogenous addition of PtdIns(5)P. Taken together, these results suggest that TMEM55a negatively regulates the phagocytosis of large particles by reducing phagosomal PtdIns(4,5)P2 accumulation during cup formation.
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- 2018
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14. Inhibitory receptor FcγRIIb mediates the effects of IgG on a phagosome acidification and a sequential dephosphorylation system comprising SHIPs and Inpp4a
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Tomohiro Segawa, Kenshiro Miyamoto, Osamu Hazeki, Kiyomi Nigorikawa, Tomoki Tanizawa, Shin Morioka, Kaoru Hazeki, and Atsuko Nukuda
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0301 basic medicine ,Phagocytic cup ,Phagocytosis ,Phagosome acidification ,Immunology ,Biology ,Microbiology ,Dephosphorylation ,03 medical and health sciences ,Mice ,Phosphatidylinositol Phosphates ,Phagosomes ,Animals ,Phosphorylation ,RNA, Small Interfering ,Molecular Biology ,Protein kinase B ,Phagosome ,Macrophages ,Receptors, IgG ,Cell Biology ,Hydrogen-Ion Concentration ,Molecular biology ,Phosphoric Monoester Hydrolases ,Pleckstrin homology domain ,Oncogene Protein v-akt ,030104 developmental biology ,Infectious Diseases ,RAW 264.7 Cells ,Immunoglobulin G ,Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases ,Proto-oncogene tyrosine-protein kinase Src ,Protein Binding - Abstract
The relative abundance of phosphoinositide (PI) species on the phagosome membrane fluctuates over the course of phagocytosis. PtdIns(3,4,5)P3 and PtdIns(3,4)P2 rapidly increase in the forming of the phagocytic cup, following which they disappear after sealing of the cup. In the present study, we monitored the clearance of these PI species using the enhanced green fluorescent protein-fused pleckstrin homology domain of Akt, a fluorescence probe that binds both PtdIns(3,4,5)P3 and PtdIns(3,4)P2 in Raw 264.7 macrophages. The clearance of PIs was much faster when the phagocytosed particles were coated with IgG. The effect of IgG was not observed in the macrophages deficient in FcγRIIb, an inhibitory IgG receptor. To identify the lipid phosphatases responsible for the FcγRIIb-accelerated PI clearance, we prepared a panel of lipid phosphatase-deficient cells. The lack of a PI 5-phosphatase Src homology 2 domain-containing inositol-5-phosphatase (SHIP)1 or SHIP2 impaired the FcγRIIb-accelerated clearance of PIs. The lack of a PI 4-phosphatase Inpp4a also impaired the accelerated PIs clearance. In the FcγRIIb- and Inpp4a-deficient cells, acidification of the formed phagosome was slowed. These results suggested that FcγRIIb drives the sequential dephosphorylation system comprising SHIPs and Inpp4a, and accelerates phagosome acidification.
- Published
- 2017
15. Phosphoinositide phosphatase Sac3 regulates the cell surface expression of scavenger receptor A and formation of lipid droplets in macrophages
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Hiromi Sakamoto, Osamu Hazeki, Shunsuke Takasuga, Kaoru Hazeki, Michiko Ohmura, Shin Morioka, Kiyomi Nigorikawa, and Takuma Matsumura
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0301 basic medicine ,Scaffold protein ,Phosphatase ,Cell ,Biology ,03 medical and health sciences ,PIKFYVE ,Mice ,0302 clinical medicine ,Lipid droplet ,medicine ,Animals ,Humans ,Scavenger receptor ,Foam cell ,Receptors, Scavenger ,Gene knockdown ,Flavoproteins ,Macrophages ,Cell Membrane ,Scavenger Receptors, Class A ,Cell Biology ,Lipid Droplets ,Phosphoric Monoester Hydrolases ,Cell biology ,030104 developmental biology ,medicine.anatomical_structure ,RAW 264.7 Cells ,Gene Knockdown Techniques ,Phosphoinositide Phosphatases ,030217 neurology & neurosurgery - Abstract
The findings of this study suggest that the phosphoinositide phosphatase Sac3 maintains the protein level of scavenger receptor A (SR-A) and regulates foam cell formation. RAW264.7 macrophages were transfected with short hairpin RNAs that target Sac3. The knockdown decreased the level of the cell surface SR-A and suppressed the acetylated low density lipoprotein-induced foam cell formation. The associated regulator of PIKfyve (ArPIKfyve) is a scaffold protein that protects Sac3 from proteasome-dependent degradation. The knockdown of ArPIKfyve decreased Sac3, cell surface SR-A, and foam cell formation. The knockdown of PIKfyve had no effect on SR-A protein levels. These results suggest that the ArPIKfyve-Sac3 complex regulates SR-A protein levels independently of its effect on PIKfyve activity.
- Published
- 2017
16. Inpp5e increases the Rab5 association and phosphatidylinositol 3-phosphate accumulation at the phagosome through an interaction with Rab20
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Osamu Hazeki, Kaoru Hazeki, Tomohiro Segawa, Shunsuke Takasuga, Shin Morioka, Ying Guo, Kiyomi Nigorikawa, and Ken Asanuma
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Phagocytosis ,Phagosome acidification ,Phosphatase ,Biology ,Transfection ,Biochemistry ,Mice ,chemistry.chemical_compound ,Phosphatidylinositol Phosphates ,Phagosomes ,INPP5E ,Animals ,Molecular Biology ,Cells, Cultured ,rab5 GTP-Binding Proteins ,Phagosome ,Solid particle ,Macrophages ,Phosphatidylinositol 3-phosphate ,Cell Biology ,Phosphoric Monoester Hydrolases ,Cell biology ,chemistry ,rab GTP-Binding Proteins ,Guanine nucleotide exchange factor ,Acids ,Protein Binding - Abstract
Phosphoinositide 5′-phosphatases have been implicated in the regulation of phagocytosis. However, their precise roles in the phagocytic process are poorly understood. We prepared RAW264.7 macrophages deficient in Inpp5e (shInpp5e) to clarify the role of this lipid phosphatase. In the shInpp5e cells, the uptake of solid particles was increased and the rate of phagosome acidification was accelerated. As expected, levels of PtdIns(3,4,5)P3 and PtdIns(3,4)P2 were increased and decreased respectively, on the forming phagocytic cups of these cells. Unexpectedly, the most prominent consequence of the Inpp5e deficiency was the decreased accumulation of PtdIns3P and Rab5 on the phagosome. The expression of a constitutively active form of Rab5b in the shInpp5e cells rescued the PtdIns3P accumulation. Rab20 has been reported to regulate the activity of Rabex5, a guanine nucleotide exchange factor for Rab5. The association of Rab20 with the phagosome was remarkably abrogated in the shInpp5e cells. Over-expression of Rab20 increased phagosomal PtdIns3P accumulation and delayed its elimination. These results suggest that Inpp5e, through functional interactions with Rab20 on the phagosome, activates Rab5, which, in turn, increases PtdIns3P and delays phagosome acidification.
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- 2014
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17. Inositol Polyphosphate-4-Phosphatase Type I Negatively Regulates Phagocytosis via Dephosphorylation of Phagosomal PtdIns(3,4)P2
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Osamu Hazeki, Kiyomi Nigorikawa, Mikiko Miyake, Kaoru Hazeki, Shin Morioka, Yumio Omori, Junko Sasaki, Ying Guo, and Takehiko Sasaki
- Subjects
Male ,Phagocytosis ,Blotting, Western ,lcsh:Medicine ,Mice, Transgenic ,Biology ,Phosphatidylinositols ,Endocytosis ,Dephosphorylation ,Cell membrane ,Mice ,chemistry.chemical_compound ,Phagosomes ,medicine ,Animals ,Humans ,Inositol ,Phosphorylation ,lcsh:Science ,Cells, Cultured ,Phagosome ,Mice, Knockout ,Multidisciplinary ,Macrophages ,lcsh:R ,Cell Membrane ,Phosphoric Monoester Hydrolases ,Cell biology ,medicine.anatomical_structure ,chemistry ,Apoptosis ,lcsh:Q ,Female ,Research Article - Abstract
Phagocytosis is a highly conserved process whereby phagocytic cells engulf pathogens and apoptotic bodies. The present study focused on the role of inositol polyphosphate-4-phosphatase type I (Inpp4a) in phagocytosis. Raw264.7 cells that express shRNA against Inpp4a (shInpp4a cells) showed significantly increased phagocytic activity. The introduction of shRNA-resistant human Inpp4a abolished this increase. Macrophages from Inpp4a knockout mice showed similar increases in the phagocytic activity. Inpp4a was recruited to the phagosome membrane by a mechanism other than the direct interaction with Rab5. PtdIns(3,4)P2 increased on the phagosome of shInpp4a cells, while PtdIns(3)P significantly decreased. The results indicate that Inpp4a negatively regulates the phagocytic activity of macrophages as a member of the sequential dephosphorylation system that metabolizes phagosomal PtdIns(3,4,5)P3 to PtdIns(3)P.
- Published
- 2015
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