120 results on '"Yoshitomo Suhara"'
Search Results
2. Effect of lonidamine derivatives on the inhibition of transformed cell area expansion
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Megumi Aoyama, Taiki Homma, Ryohto Koharazawa, Yoshitomo Suhara, and Kentaro Semba
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Transformed cell ,Cancer cells ,Lonidamine ,Biology (General) ,QH301-705.5 ,Biochemistry ,QD415-436 - Abstract
Expansion of transformed cell area is regulated by the surrounding nontransformed cells. Lonidamine (LND) was recently found to regulate transformed cell area expansion through suppressing the cell motility of nontransformed cells; however, the structure–activity relationship between LND and this inhibitory activity has yet to be elucidated. We synthesized several LND derivatives and evaluated their inhibitory activity against the expansion of transformed cell area and found that the halogenation pattern on the benzene ring moiety, the carboxylic acid moiety, and the overall hydrophobicity of the molecule were correlated with inhibition activity. We also found that the localization of the tight junction protein, zonula occludens-1 (ZO-1), in nontransformed cells was significantly altered after treatment with the LND derivatives that displayed inhibitory activity. Further studies with LND derivatives and monitoring the localization of ZO-1 may help to develop more active compounds for suppressing transformed cell area expansion and lead to new anticancer treatments.
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- 2023
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3. Eldecalcitol is more effective in promoting osteogenesis than alfacalcidol in Cyp27b1-knockout mice.
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Yoshihisa Hirota, Kimie Nakagawa, Keigo Isomoto, Toshiyuki Sakaki, Noboru Kubodera, Maya Kamao, Naomi Osakabe, Yoshitomo Suhara, and Toshio Okano
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Medicine ,Science - Abstract
Calcium (Ca) absorption from the intestinal tract is promoted by active vitamin D (1α,25D3). Vitamin D not only promotes Ca homeostasis, but it also inhibits bone resorption and promotes osteogenesis, thus playing a role in the maintenance of normal bone metabolism. Because 1α,25D3 plays an important role in osteogenesis, vitamin D formulations, such as alfacalcidol (ALF) and eldecalcitol (ELD), are used for treating osteoporosis. While it is known that, in contrast to ALF, ELD is an active ligand that directly acts on bone, the reason for its superior osteogenesis effects is unknown. Cyp27b1-knockout mice (Cyp27b1-/-mice) are congenitally deficient in 1α,25D3 and exhibit marked hypocalcemia and high parathyroid hormone levels, resulting in osteodystrophy involving bone hypocalcification and growth plate cartilage hypertrophy. However, because the vitamin D receptor is expressed normally in Cyp27b1-/-mice, they respond normally to 1α,25D3. Accordingly, in Cyp27b1-/-mice, the pharmacological effects of exogenously administered active vitamin D derivatives can be analyzed without being affected by 1α,25D3. We used Cyp27b1-/-mice to characterize and clarify the superior osteogenic effects of ELD on the bone in comparison with ALF. The results indicated that compared to ALF, ELD strongly induces ECaC2, calbindin-D9k, and CYP24A1 in the duodenum, promoting Ca absorption and decreasing the plasma concentration of 1α,25D3, resulting in improved osteogenesis. Because bone morphological measurements demonstrated that ELD has stronger effects on bone calcification, trabecular formation, and cancellous bone density than ALF, ELD appears to be a more effective therapeutic agent for treating postmenopausal osteoporosis, in which cancellous bone density decreases markedly. By using Cyp27b1-/-mice, this study was the first to succeed in clarifying the osteogenic effect of ELD without any influence of endogenous 1α,25D3. Furthermore, ELD more strongly enhanced bone mineralization, trabecular proliferation, and cancellous bone density than did ALF. Thus, ELD is expected to show an effect on postmenopausal osteoporosis, in which cancellous bone mineral density decreases markedly. In the future, this study may enable the development of next-generation active vitamin D derivatives with higher affinity for bone than ELD.
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- 2018
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4. Comparison of the sympathetic stimulatory abilities of B-type procyanidins based on induction of uncoupling protein-1 in brown adipose tissue (BAT) and increased plasma catecholamine (CA) in mice.
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Yuta Nakagawa, Kana Ishimura, Satomi Oya, Masaki Kamino, Yasuyuki Fujii, Fumio Nanba, Toshiya Toda, Takeshi Ishii, Takahiro Adachi, Yoshitomo Suhara, and Naomi Osakabe
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Medicine ,Science - Abstract
OBJECTIVES:We previously found that elevated energy expenditure following a single oral dose of flavan 3-ols (FL), a mixture of catechins and B type procyanidins, is caused by sympathetic nerve activation. In the present study, we compared the activity of the FL components (-)-epicatechin (EC; monomer), procyanidin B2 (B2; dimer), procyanidin C1 (C1; trimer), cinnamtannin A2 (A2; tetramer), and more than pentamer fraction (P5). METHODS:Male ICR mice were treated with a single oral dose of FL, EC, B2, C1, A2, or P5. The animals were sacrificed and blood and brown adipose tissue (BAT) sampled. The plasma catecholamine (CA) levels and BAT uncoupling protein (UCP)-1 mRNA expression were determined. RESULTS:A single dose of 10 mg/kg FL significantly increased plasma CA and UCP-1 mRNA levels. B2, C1, and A2, but not EC and P5 (all at 1 mg/kg), significantly increased plasma adrenaline levels. Plasma noradrenaline was significantly elevated by B2 and A2, but not by EC, C1, or P5. UCP-1 mRNA levels were significantly increased by C1 and P5. In the dose response study of A2, 10-3 mg/kg A2 increased UCP-1 mRNA levels significantly, but not 10-2 and 10-1 mg/kg A2. In addition, combination treatment with 10-1 mg/kg A2 and yohimbine, an α2 adrenalin blocker, remarkably increased UCP-1 mRNA levels. CONCLUSION:These results suggest that FL and its components, except EC, increase UCP-1 mRNA and plasma CA with varying efficacy.
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- 2018
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5. Elucidation of the Interaction between Flavan-3-ols and Bovine Serum Albumin and Its Effect on Their In-Vitro Cytotoxicity
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Yasuyuki Fujii, Yoshitomo Suhara, Yusuke Sukikara, Tomohiro Teshima, Yoshihisa Hirota, Kenjiro Yoshimura, and Naomi Osakabe
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flavan-3-ols ,bovine serum albumin ,docking simulation ,b-type procyanidin ,cytotoxicity ,Organic chemistry ,QD241-441 - Abstract
Flavan-3-ols (FLs), specifically catechin and its oligomer B-type procyanidins, are suggested to potently bind to bovine serum albumin (BSA). We examined the interaction between BSA and FLs by fluorescence quenching and found the following order of binding activities to BSA: cinnamtannin A2 (A2; tetramer) > procyanidin C1 (C1; trimer) ≈ procyanidin B2 (B2, dimer) > (−)epicatechin (EC, monomer). Docking simulations between BSA and each compound at the binding site showed that the calculated binding energies were consistent with the results of our experimental assay. FLs exerted cytotoxicity at 1000 μg/mL in F11 cell culture with fetal bovine serum containing BSA. In culture containing serum-free medium, FLs exhibited significant cell proliferation at 10−4 μg/mL and cytotoxicity was observed at concentrations greater than 10 μg/mL. Results of this study suggest that interactions between polyphenols and BSA should be taken into account when evaluating procyanidin in an in vitro cell culture system.
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- 2019
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6. New Aspects of Vitamin K Research with Synthetic Ligands: Transcriptional Activity via SXR and Neural Differentiation Activity
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Yoshihisa Hirota and Yoshitomo Suhara
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vitamin K ,ã-glutamyl carboxylase (GGCX) ,steroid and xenobiotic receptor (SXR) ,neural differentiation action ,UBIAD1 ,derivatives research ,Biology (General) ,QH301-705.5 ,Chemistry ,QD1-999 - Abstract
Vitamin K is classified into three homologs depending on the side-chain structure, with 2-methyl-1,4-naphthoqumone as the basic skeleton. These homologs are vitamin K1 (phylloquinone: PK), derived from plants with a phythyl side chain; vitamin K2 (menaquinone-n: MK-n), derived from intestinal bacteria with an isoprene side chain; and vitamin K3 (menadione: MD), a synthetic product without a side chain. Vitamin K homologs have physiological effects, including in blood coagulation and in osteogenic activity via γ-glutamyl carboxylase and are used clinically. Recent studies have revealed that vitamin K homologs are converted to MK-4 by the UbiA prenyltransferase domain-containing protein 1 (UBIAD1) in vivo and accumulate in all tissues. Although vitamin K is considered to have important physiological effects, its precise activities and mechanisms largely remain unclear. Recent research on vitamin K has suggested various new roles, such as transcriptional activity as an agonist of steroid and xenobiotic nuclear receptor and differentiation-inducing activity in neural stem cells. In this review, we describe synthetic ligands based on vitamin K and exhibit that the strength of biological activity can be controlled by modification of the side chain part.
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- 2019
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7. UBIAD1 Plays an Essential Role in the Survival of Pancreatic Acinar Cells
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Kimie Nakagawa, Kiyomi Fujiwara, Akihiro Nishimura, Chinami Murakami, Kanaha Kawamoto, Chihiro Ichinose, Yumi Kunitou, Yoshitomo Suhara, Toshio Okano, and Hiroshi Hasegawa
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UBIAD1 ,MK-4 ,tamoxifen ,knockout mice ,pancreas ,acinar cells ,Biology (General) ,QH301-705.5 ,Chemistry ,QD1-999 - Abstract
UbiA prenyltransferase domain-containing protein 1 (UBIAD1) is a vitamin K2 biosynthetic enzyme. We previously showed the lethality of this enzyme in UBIAD1 knockout mice during the embryonic stage. However, the biological effects of UBIAD1 deficiency after birth remain unclear. In the present study, we used a tamoxifen-inducible systemic UBIAD1 knockout mouse model to determine the role of UBIAD1 in adult mice. UBIAD1 knockout resulted in the death of the mice within about 60 days of administration of tamoxifen. The pancreas presented with the most prominent abnormality in the tamoxifen-induced UBIAD1 knockout mice. The pancreas was reduced remarkably in size; furthermore, the pancreatic acinar cells disappeared and were replaced by vacuoles. Further analysis revealed that the vacuoles were adipocytes. UBIAD1 deficiency in the pancreatic acinar cells caused an increase in oxidative stress and autophagy, leading to apoptotic cell death in the tamoxifen-induced UBIAD 1 knockout mice. These results indicate that UBIAD1 is essential for maintaining the survival of pancreatic acinar cells in the pancreas.
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- 2019
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8. Functional characterization of the vitamin K2 biosynthetic enzyme UBIAD1.
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Yoshihisa Hirota, Kimie Nakagawa, Natsumi Sawada, Naoko Okuda, Yoshitomo Suhara, Yuri Uchino, Takashi Kimoto, Nobuaki Funahashi, Maya Kamao, Naoko Tsugawa, and Toshio Okano
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Medicine ,Science - Abstract
UbiA prenyltransferase domain-containing protein 1 (UBIAD1) plays a significant role in vitamin K2 (MK-4) synthesis. We investigated the enzymological properties of UBIAD1 using microsomal fractions from Sf9 cells expressing UBIAD1 by analysing MK-4 biosynthetic activity. With regard to UBIAD1 enzyme reaction conditions, highest MK-4 synthetic activity was demonstrated under basic conditions at a pH between 8.5 and 9.0, with a DTT ≥0.1 mM. In addition, we found that geranyl pyrophosphate and farnesyl pyrophosphate were also recognized as a side-chain source and served as a substrate for prenylation. Furthermore, lipophilic statins were found to directly inhibit the enzymatic activity of UBIAD1. We analysed the aminoacid sequences homologies across the menA and UbiA families to identify conserved structural features of UBIAD1 proteins and focused on four highly conserved domains. We prepared protein mutants deficient in the four conserved domains to evaluate enzyme activity. Because no enzyme activity was detected in the mutants deficient in the UBIAD1 conserved domains, these four domains were considered to play an essential role in enzymatic activity. We also measured enzyme activities using point mutants of the highly conserved aminoacids in these domains to elucidate their respective functions. We found that the conserved domain I is a substrate recognition site that undergoes a structural change after substrate binding. The conserved domain II is a redox domain site containing a CxxC motif. The conserved domain III is a hinge region important as a catalytic site for the UBIAD1 enzyme. The conserved domain IV is a binding site for Mg2+/isoprenyl side-chain. In this study, we provide a molecular mapping of the enzymological properties of UBIAD1.
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- 2015
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9. A Single Oral Administration of Theaflavins Increases Energy Expenditure and the Expression of Metabolic Genes.
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Naoto Kudo, Yasunori Arai, Yoshitomo Suhara, Takeshi Ishii, Tsutomu Nakayama, and Naomi Osakabe
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Medicine ,Science - Abstract
Theaflavins are polyphenols found in black tea, whose physiological activities are not well understood. This study on mice evaluated the influence of a single oral administration of theaflavins on energy metabolism by monitoring the initial metabolic changess in skeletal muscle and brown adipose tissue (BAT). Oxygen consumption (VO2) and energy expenditure (EE) were increased significantly in mice treated with theaflavin rich fraction (TF) compared with the group administered vehicle alone. There was no difference in locomotor activity. Fasting mice were euthanized under anesthesia before and 2 and 5, 20-hr after treatment with TF or vehicle. The mRNA levels of uncoupling protein-1 (UCP-1) and peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α) in BAT were increased significantly 2-hr after administration ofTF. The levels of UCP-3 and PGC-1α in the gastrocnemius muscle were increased significantly 2 and 5-hr after administration of TF. The concentration of phosphorylated AMP-activated protein kinase (AMPK) 1α was also increased significantly in the gastrocnemius 2 and 5-hr after treatment with TF. These results indicate that TF significantly enhances systemic energy expenditure, as evidenced by an increase in expression of metabolic genes.
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- 2015
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10. Substitution at the C-3 Position of Catechins Has an Influence on the Binding Affinities against Serum Albumin
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Masaki Ikeda, Manabu Ueda-Wakagi, Kaori Hayashibara, Rei Kitano, Masaya Kawase, Kunihiro Kaihatsu, Nobuo Kato, Yoshitomo Suhara, Naomi Osakabe, and Hitoshi Ashida
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catechin ,serum albumin ,interaction ,docking study ,fluorescence analysis ,Organic chemistry ,QD241-441 - Abstract
It is known that catechins interact with the tryptophan (Trp) residue at the drug-binding site of serum albumin. In this study, we used catechin derivatives to investigate which position of the catechin structure strongly influences the binding affinity against bovine serum albumin (BSA) and human serum albumin (HSA). A docking simulation showed that (−)-epigallocatechin gallate (EGCg) interacted with both Trp residues of BSA (one at drug-binding site I and the other on the molecular surface), mainly by π–π stacking. Fluorescence analysis showed that EGCg and substituted EGCg caused a red shift of the peak wavelength of Trp similarly to warfarin (a drug-binding site I-specific compound), while 3-O-acyl-catechins caused a blue shift. To evaluate the binding affinities, the quenching constants were determined by the Stern–Volmer equation. A gallate ester at the C-3 position increased the quenching constants of the catechins. Against BSA, acyl substitution increased the quenching constant proportionally to the carbon chain lengths of the acyl group, whereas methyl substitution decreased the quenching constant. Against HSA, neither acyl nor methyl substitution affected the quenching constant. In conclusion, substitution at the C-3 position of catechins has an important influence on the binding affinity against serum albumin.
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- 2017
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11. Vitamin K2 biosynthetic enzyme, UBIAD1 is essential for embryonic development of mice.
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Kimie Nakagawa, Natsumi Sawada, Yoshihisa Hirota, Yuri Uchino, Yoshitomo Suhara, Tomoka Hasegawa, Norio Amizuka, Tadashi Okamoto, Naoko Tsugawa, Maya Kamao, Nobuaki Funahashi, and Toshio Okano
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Medicine ,Science - Abstract
UbiA prenyltransferase domain containing 1 (UBIAD1) is a novel vitamin K2 biosynthetic enzyme screened and identified from the human genome database. UBIAD1 has recently been shown to catalyse the biosynthesis of Coenzyme Q10 (CoQ10) in zebrafish and human cells. To investigate the function of UBIAD1 in vivo, we attempted to generate mice lacking Ubiad1, a homolog of human UBIAD1, by gene targeting. Ubiad1-deficient (Ubiad1(-/-)) mouse embryos failed to survive beyond embryonic day 7.5, exhibiting small-sized body and gastrulation arrest. Ubiad1(-/-) embryonic stem (ES) cells failed to synthesize vitamin K2 but were able to synthesize CoQ9, similar to wild-type ES cells. Ubiad1(+/-) mice developed normally, exhibiting normal growth and fertility. Vitamin K2 tissue levels and synthesis activity were approximately half of those in the wild-type, whereas CoQ9 tissue levels and synthesis activity were similar to those in the wild-type. Similarly, UBIAD1 expression and vitamin K2 synthesis activity of mouse embryonic fibroblasts prepared from Ubiad1(+/-) E15.5 embryos were approximately half of those in the wild-type, whereas CoQ9 levels and synthesis activity were similar to those in the wild-type. Ubiad1(-/-) mouse embryos failed to be rescued, but their embryonic lifespans were extended to term by oral administration of MK-4 or CoQ10 to pregnant Ubiad1(+/-) mice. These results suggest that UBIAD1 is responsible for vitamin K2 synthesis but may not be responsible for CoQ9 synthesis in mice. We propose that UBIAD1 plays a pivotal role in embryonic development by synthesizing vitamin K2, but may have additional functions beyond the biosynthesis of vitamin K2.
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- 2014
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12. Sympathetic Hyperactivity Induced by Oral Administration of the Astringent (-)-Epicatechin Tetramer Cinnamtannin A2 Through Activation of Transient Receptor Potential Channels Via ROS
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Taiki Fushimi, Chie Hirahata, Kento Hiroki, Yasuyuki Fujii, Yoshitomo Suhara, and Naomi Osakabe
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- 2023
13. A novel vitamin K derived anticoagulant tolerant to genetic variations of vitamin K epoxide reductase
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Darrel W. Stafford, Xuejie Chen, G. Paul Savage, Jian Ke Tie, Da Yun Jin, Natsuko Furukawa, Craig M. Williams, Yizhou Liu, and Yoshitomo Suhara
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Vitamin ,Vitamin K ,medicine.drug_class ,030204 cardiovascular system & hematology ,Article ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Vitamin K Epoxide Reductases ,medicine ,Animals ,Warfarin resistance ,Blood Coagulation ,Clotting factor ,chemistry.chemical_classification ,Chemistry ,Warfarin ,Anticoagulants ,Vitamin K 1 ,Hematology ,Vitamin K antagonist ,Enzyme ,Biochemistry ,Carboxylation ,Vitamin K epoxide reductase ,medicine.symptom ,medicine.drug - Abstract
Background Vitamin K antagonists (VKAs), such as warfarin, have remained the cornerstone of oral anticoagulation therapy in the prevention and treatment of thromboembolism for more than half a century. They function by impairing the biosynthesis of vitamin K-dependent (VKD) clotting factors through the inhibition of vitamin K epoxide reductase (VKOR). The challenge of VKAs therapy is their narrow therapeutic index and highly variable dosing requirements, which are partially the result of genetic variations of VKOR. Objectives The goal of this study was to search for an improved VKA that is tolerant to the genetic variations of its target enzyme. Methods A series of vitamin K derivatives with benzyl and related side-chain substitutions at the 3-position of 1,4-naphthoquinone were synthesized. The role of these compounds in VKD carboxylation was evaluated by mammalian cell-based assays and conventional in vitro activity assays. Results Our results showed that replacing the phytyl side-chain with a methylene cyclooctatetraene (COT) moiety at the 3-position of vitamin K1 converted it from a substrate to an inhibitor for VKD carboxylation. Strikingly, this COT-vitamin K derivative displayed a similar inhibition potency in warfarin-resistant VKOR mutations whose warfarin resistance varied more than 400-fold. Further characterization of COT-vitamin K for the inhibition of VKD carboxylation suggested that this compound targets multiple enzymes in the vitamin K redox cycle. Importantly, the anticoagulation effect of COT-vitamin K can be rescued with high doses of vitamin K1 . Conclusion We discovered a vitamin K analogue that functions as a VKA and is tolerant to genetic variations in the target enzyme.
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- 2021
14. Synthesis of new vitamin K derivatives with a ketone group at the C-1′ position of the side chain and their conversion to menaquinone-4
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Natsuko Furukawa, Xuejie Chen, Satoshi Asano, Marina Matsumoto, Yuxin Wu, Kohei Murata, Atsuko Takeuchi, Chisato Tode, Taiki Homma, Ryohto Koharazawa, Kouki Usami, Jian-Ke Tie, Yoshihisa Hirota, and Yoshitomo Suhara
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Inorganic Chemistry ,Organic Chemistry ,Spectroscopy ,Analytical Chemistry - Published
- 2023
15. Recent Advances in the Medicinal Chemistry of Vitamin K Derivatives: An Overview (2000–2021)
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Shinya Fujii, Yoshitomo Suhara, and Hiroyuki Kagechika
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In recent decades, many physiological and pharmacological functions of vitamin K other than its role as the cofactor of γ-glutamyl carboxylase (GGCX) have been identified, and consequently, many vitamin K derivatives and related congeners, including putative metabolites, have been designed and synthesized. Their biological activities include antitumor activity, anti-inflammatory activity, neuroprotective effects, neural differentiation-inducing activity, and modulating potency toward the nuclear steroid and xenobiotic receptor (SXR). These activities make vitamin K and its derivatives attractive candidates for drug discovery. In this chapter, an overview of recent advances in the medicinal chemistry of vitamin K, focusing especially on SXR modulation, neural differentiation, and antitumor activities, was provided.
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- 2022
16. Author response for 'Naturally occurring UBIAD1 mutations differentially affect menaquinone biosynthesis and vitamin K‐dependent carboxylation'
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Yizhou Liu, Craig M. Williams, Da-Yun Jin, Darrel W. Stafford, Xuejie Chen, Jian Ke Tie, Natsuko Furukawa, and Yoshitomo Suhara
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Menaquinone biosynthesis ,Carboxylation ,Biochemistry ,Chemistry ,Vitamin k ,Affect (psychology) - Published
- 2021
17. Naturally occurring UBIAD1 mutations differentially affect menaquinone biosynthesis and vitamin K-dependent carboxylation
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Jian Ke Tie, Darrel W. Stafford, Yoshitomo Suhara, Natsuko Furukawa, Xuejie Chen, Craig M. Williams, Da-Yun Jin, and Yizhou Liu
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Vitamin K ,Prenyltransferase ,medicine.disease_cause ,Biochemistry ,Cofactor ,Article ,chemistry.chemical_compound ,Mice ,Biosynthesis ,medicine ,Animals ,Humans ,Molecular Biology ,Gene ,Corneal Dystrophies, Hereditary ,Mutation ,biology ,Chemistry ,HEK 293 cells ,Vitamin K 2 ,Cell Biology ,Dimethylallyltranstransferase ,Phenotype ,HEK293 Cells ,Carboxylation ,biology.protein - Abstract
UbiA prenyltransferase domain-containing protein-1 (UBIAD1) is responsible for the biosynthesis of menaquinone-4 (MK-4), a cofactor for extrahepatic carboxylation of vitamin K-dependent (VKD) proteins. Genetic variations of UBIAD1 are mainly associated with Schnyder corneal dystrophy (SCD), a disease characterized by abnormal accumulation of cholesterol in the cornea. Results from in vitro studies demonstrate that SCD-associated UBIAD1 mutations are defective in MK-4 biosynthesis. However, SCD patients do not exhibit typical phenotypes associated with defects of MK-4 or VKD carboxylation. Here, we coupled UBIAD1’s biosynthetic activity of MK-4 with VKD carboxylation in HEK293 cells that stably express a chimeric VKD reporter protein. The endogenous Ubiad1 gene in these cells were knocked out by CRISPR-Cas9-mediated genome editing. The effect of UBIAD1 mutations on MK-4 biosynthesis and VKD carboxylation were evaluated in Ubiad1-deficient reporter cells by determining the production of MK-4 or by measuring the efficiency of reporter-protein carboxylation. Our results show that the hot-spot mutation N102S has a moderate impact on MK-4 biosynthesis (retained ~82% activity) but does not affect VKD carboxylation. However, the G186R mutation significantly affected both MK-4 biosynthesis and VKD carboxylation. Other mutations exhibit varying degrees of effects on MK-4 biosynthesis and VKD carboxylation. These results are consistent with in vivo results obtained from gene knock-in mice and SCD patients. Our findings suggest that UBIAD1’s MK-4 biosynthetic activity does not directly correlate with the phenotypes of SCD patients. The established cell-based assays in this study provide a powerful tool for the functional studies of UBIAD1 in a cellular milieu.
- Published
- 2021
18. Development of Selective TGR5 Ligands Based on the 5,6,7,8-Tetrahydro-5,5,8,8-tetramethylnaphthalene Skeleton
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Yuta Yanase, Hidetomo Yokoo, Makoto Makishima, Takashi Misawa, Ryusei Terui, Yoshitomo Suhara, and Yosuke Demizu
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Pharmacology ,Agonist ,Dose-Response Relationship, Drug ,Molecular Structure ,Stereochemistry ,Chemistry ,medicine.drug_class ,Organic Chemistry ,Ligands ,Biochemistry ,G protein-coupled bile acid receptor ,Receptors, G-Protein-Coupled ,Retinoic acid receptor ,Structure-Activity Relationship ,Drug Development ,Drug Discovery ,medicine ,Molecular Medicine ,Humans ,Farnesoid X receptor ,General Pharmacology, Toxicology and Pharmaceutics ,Receptor ,Cytotoxicity ,IC50 ,G protein-coupled receptor - Abstract
TGR5, a G-protein-coupled receptor (GPCR), plays an important role in several physiological functions. TGR5 activation through bile acids induces an increase in energy expenditure. Therefore, synthetic TGR5 ligands could be useful for the treatment of obesity or dyslipidemia. In this study, we designed and synthesized a set of TGR5 ligands with a 5,6,7,8-tetrahydro-5,5,8,8-tetramethylnaphthalene (TMN) skeleton, and evaluated their TGR5 agonistic activity. We also investigated the selectivity of the synthesized compounds for TGR5 relative to the farnesoid X receptor (FXR) and retinoic acid receptor (RAR). Our results show that compound 4 b [N-(2-chlorophenyl)-5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenecarboxamide] exhibited potent TGR5 agonist activity with an IC50 value of 8.4 nM without significant cytotoxicity. In addition, compound 4 b showed only slight agonistic activity toward FXR and RAR at 1 μM treatment. These data indicate that compound 4 b is a selective TGR5 agonist, and could be a promising therapeutic agent for dyslipidemia.
- Published
- 2020
19. Study on structure-activity relationship of vitamin K derivatives: Conversion of the naphthoquinone part into another aromatic ring and evaluation of their neuronal differentiation-inducing activity
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Yuta Takagi, Yoshihisa Hirota, Atsuko Takeuchi, Maya Kamao, Yoshitomo Suhara, Naomi Osakabe, Chisato Tode, Seiya Soda, Hiroshi Yoshimura, and Mayu Okazeri
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Quantitative structure–activity relationship ,Vitamin K ,Stereochemistry ,Clinical Biochemistry ,Pharmaceutical Science ,Quantitative Structure-Activity Relationship ,Ring (chemistry) ,01 natural sciences ,Biochemistry ,chemistry.chemical_compound ,Mice ,Drug Discovery ,Side chain ,Benzene Derivatives ,Benzoquinones ,Structure–activity relationship ,Moiety ,Animals ,Molecular Biology ,Neurons ,Dose-Response Relationship, Drug ,Molecular Structure ,010405 organic chemistry ,Organic Chemistry ,Cell Differentiation ,Benzoquinone ,Naphthoquinone ,0104 chemical sciences ,Quinone ,010404 medicinal & biomolecular chemistry ,chemistry ,Molecular Medicine ,Naphthoquinones - Abstract
We synthesized novel vitamin K derivatives by converting the naphthoquinone group to benzene derivatives and benzoquinone. We evaluated their neuronal differentiation activities to investigate the effect of the quinone moiety on this process. We observed that the 1,4-quinone as well as the side chain part play important roles in neuronal differentiation. We also performed QSAR analysis to predict the compounds which would have higher differentiation activity.
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- 2020
20. Paradigm Shift of Vitamin K Research: Discovery of New Biological Activities of Vitamin K and Synthesis of the Analogues
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Yoshihisa Hirota and Yoshitomo Suhara
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- 2017
21. Synthesis of novel vitamin K derivatives with alkylated phenyl groups introduced at the ω-terminal side chain and evaluation of their neural differentiation activities
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Yuta Takagi, Akimori Wada, Makoto Makishima, Kimito Kimura, Yoshitomo Suhara, Shigefumi Kuwahara, Rie Sakane, Yoshihisa Hirota, and Michiyasu Ishizawa
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0301 basic medicine ,Vitamin K ,Alkylation ,Stereochemistry ,medicine.medical_treatment ,Cellular differentiation ,Clinical Biochemistry ,Pharmaceutical Science ,030204 cardiovascular system & hematology ,PC12 Cells ,Biochemistry ,Cofactor ,Steroid ,Mice ,Structure-Activity Relationship ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Neural Stem Cells ,Drug Discovery ,medicine ,Side chain ,Animals ,Structure–activity relationship ,Phenyl group ,Receptor ,Molecular Biology ,Cells, Cultured ,biology ,Organic Chemistry ,Cell Differentiation ,Ligand (biochemistry) ,Rats ,030104 developmental biology ,Microscopy, Fluorescence ,chemistry ,biology.protein ,Molecular Medicine ,Microtubule-Associated Proteins - Abstract
Vitamin K is an essential cofactor of γ-glutamylcarboxylase as related to blood coagulation and bone formation. Menaquinone-4, one of the vitamin K homologues, is biosynthesized in the body and has various biological activities such as being a ligand for steroid and xenobiotic receptors, protection of neuronal cells from oxidative stress, and so on. From this background, we focused on the role of menaquinone in the differentiation activity of progenitor cells into neuronal cells and we synthesized novel vitamin K derivatives with modification of the ω-terminal side chain. We report here new vitamin K analogues, which introduced an alkylated phenyl group at the ω-terminal side chain. These compounds exhibited potent differentiation activity as compared to control.
- Published
- 2017
22. Determination of Menadione by Liquid Chromatography-Tandem Mass Spectrometry Using Pseudo Multiple Reaction Monitoring
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Maya Kamao, Kimie Nakagawa, Toshio Okano, Hiroshi Hasegawa, Yoshihisa Hirota, Naoko Tsugawa, and Yoshitomo Suhara
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0301 basic medicine ,Swine ,Coefficient of variation ,Analytical chemistry ,Mass spectrometry ,01 natural sciences ,Analytical Chemistry ,Ion ,03 medical and health sciences ,chemistry.chemical_compound ,Menadione ,Tandem Mass Spectrometry ,Liquid chromatography–mass spectrometry ,Lc ms ms ,Animals ,Humans ,Cells, Cultured ,Chromatography, High Pressure Liquid ,Detection limit ,Chromatography ,Molecular Structure ,Chemistry ,010401 analytical chemistry ,Selected reaction monitoring ,Vitamin K 3 ,0104 chemical sciences ,030104 developmental biology - Abstract
This study aimed to develop a menadione (MD) determination method employing liquid chromatography-tandem mass spectrometry (LC-MS/MS) using a pseudo multiple reaction monitoring (MRM) technique, wherein two quadrupoles are used to monitor the same ion. Detection limits of 40 and 2 pg were obtained for MD and its deuterium-labeled form, respectively, whereas MD intra- and inter-assay coefficient of variation values were determined as 5.4 - 8.2%, with the corresponding recoveries equaling 90.5 - 109.6%. The developed method enables determination of MD in urine, plasma, cell extract, and culture media, demonstrating that pseudo multiple reaction monitoring can achieve quantification of compounds forming no suitable product ions, such as MD.
- Published
- 2017
23. Synthesis of Novel Synthetic Vitamin K Analogues Prepared by Introduction of a Heteroatom and a Phenyl Group That Induce Highly Selective Neuronal Differentiation of Neuronal Progenitor Cells
- Author
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Yoshihisa Hirota, Atsuko Takeuchi, Akimori Wada, Chisato Tode, Kimito Kimura, Yoshitomo Suhara, Shigefumi Kuwahara, and Naomi Osakabe
- Subjects
0301 basic medicine ,Vitamin K ,Stereochemistry ,Neurogenesis ,Heteroatom ,Vitamin k ,Mice ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Neural Stem Cells ,Drug Discovery ,Side chain ,Animals ,Phenyl group ,Progenitor cell ,Cells, Cultured ,Aniline Compounds ,Chemistry ,Vitamin K2 ,Vitamin K 2 ,Vitamins ,In vitro ,Mice, Inbred C57BL ,030104 developmental biology ,nervous system ,Biochemistry ,Molecular Medicine ,Female ,Selectivity ,030217 neurology & neurosurgery - Abstract
We synthesized novel vitamin K2 analogues that incorporated a heteroatom and an aromatic ring in the side chain and evaluated their effect on the selective differentiation of neuronal progenitor cells into neurons in vitro. The results showed that a menaquinone-2 analogue bearing a p-fluoroaniline had the most potent activity, which was more than twice as great as the control. In addition, the neuronal selectivity was more than 3 times greater than the control.
- Published
- 2017
24. Nongenomic effects of 1α,25-dihydroxyvitamin D 3 on cartilage formation deduced from comparisons between Cyp27b1 and Vdr knockout mice
- Author
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Kimie Nakagawa, Naoko Tsugawa, Noboru Kubodera, Toshiyuki Sakaki, Toshio Okano, Yoshitomo Suhara, Yoshihisa Hirota, Maya Kamao, Natsumi Sawada, and Shino Mimatsu
- Subjects
0301 basic medicine ,medicine.medical_specialty ,Biophysics ,chemistry.chemical_element ,Endogeny ,Calcium ,Biology ,Biochemistry ,Calcitriol receptor ,Chondrocyte ,03 medical and health sciences ,0302 clinical medicine ,Internal medicine ,polycyclic compounds ,medicine ,Vitamin D and neurology ,Molecular Biology ,Cartilage ,Cell Biology ,030104 developmental biology ,medicine.anatomical_structure ,Endocrinology ,chemistry ,embryonic structures ,Knockout mouse ,lipids (amino acids, peptides, and proteins) ,030217 neurology & neurosurgery ,Homeostasis - Abstract
The active form of vitamin D, 1α,25-dihydroxyvitamin D3 (1α,25D3), plays an important role in the maintenance of calcium (Ca) homeostasis, bone formation, and cell proliferation and differentiation via nuclear vitamin D receptor (VDR). It is formed by the hydroxylation of vitamin D at the 1α position by 25-hydroxyvitamin D 1α-hydroxylase (CYP27B1) in the kidney. However, Cyp27b1-/- mice, deficient in CYP27B1, and VDR-deficient mice (Vdr-/-) have not been extensively examined, particularly in a comparative framework. To clarify the physiological significance of 1α,25D3 and VDR, we produced Cyp27b1-/- mice and compared their phenotypes with those of Vdr-/- mice. Cyp27b1-/- mice exhibited hypocalcemia, growth defects, and skeletogenesis dysfunction, similar to Vdr-/- mice. However, unlike Cyp27b1-/- mice, Vdr-/- mice developed alopecia. Cyp27b1-/- mice exhibited cartilage mass formation and had difficulty walking on hindlimbs. Furthermore, a phenotypic analysis was performed on Cyp27b1-/- mice provided a high Ca diet to correct for the Ca metabolic abnormality. In addition, the effects of 1α,25D3 that are not mediated by Ca metabolic regulatory activity were investigated. Even when the blood Ca concentration was corrected, abnormalities in growth and cartilage tissue formation did not improve in Cyp27b1-/- mice. These results suggested that 1α,25D3 directly controls chondrocyte proliferation and differentiation. Using Cyp27b1-/- mice produced in this study, we can analyze the physiological effects of novel vitamin D derivatives in the absence of endogenous 1α,25D3. Accordingly, this study provides a useful animal model for the development of novel vitamin D formulations that are effective for the treatment and prevention of osteoporosis.
- Published
- 2017
25. Elucidation of the Interaction between Flavan-3-ols and Bovine Serum Albumin and Its Effect on Their In-Vitro Cytotoxicity
- Author
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Yoshihisa Hirota, Yasuyuki Fujii, Yusuke Sukikara, Tomohiro Teshima, Naomi Osakabe, Kenjiro Yoshimura, and Yoshitomo Suhara
- Subjects
Pharmaceutical Science ,01 natural sciences ,Catechin ,Culture Media, Serum-Free ,Analytical Chemistry ,Anthocyanins ,chemistry.chemical_compound ,Drug Discovery ,B-type procyanidin ,Bovine serum albumin ,Cytotoxicity ,skin and connective tissue diseases ,Procyanidin B2 ,0303 health sciences ,biology ,Molecular Structure ,Serum Albumin, Bovine ,musculoskeletal system ,Molecular Docking Simulation ,Chemistry (miscellaneous) ,Molecular Medicine ,cytotoxicity ,Procyanidin C1 ,Protein Binding ,musculoskeletal diseases ,Serum albumin ,Article ,Flavan-3-ols ,Cell Line ,lcsh:QD241-441 ,03 medical and health sciences ,Tetramer ,lcsh:Organic chemistry ,docking simulation ,bovine serum albumin ,Animals ,Biflavonoids ,Proanthocyanidins ,Physical and Theoretical Chemistry ,030304 developmental biology ,Cell Proliferation ,Flavonoids ,Chromatography ,Binding Sites ,010405 organic chemistry ,Organic Chemistry ,0104 chemical sciences ,Rats ,chemistry ,Cell culture ,biology.protein ,Cattle ,Fetal bovine serum - Abstract
Flavan-3-ols (FLs), specifically catechin and its oligomer B-type procyanidins, are suggested to potently bind to bovine serum albumin (BSA). We examined the interaction between BSA and FLs by fluorescence quenching and found the following order of binding activities to BSA: cinnamtannin A2 (A2, tetramer) >, procyanidin C1 (C1, trimer) &asymp, procyanidin B2 (B2, dimer) >, (&minus, )epicatechin (EC, monomer). Docking simulations between BSA and each compound at the binding site showed that the calculated binding energies were consistent with the results of our experimental assay. FLs exerted cytotoxicity at 1000 &mu, g/mL in F11 cell culture with fetal bovine serum containing BSA. In culture containing serum-free medium, FLs exhibited significant cell proliferation at 10&minus, 4 &mu, g/mL and cytotoxicity was observed at concentrations greater than 10 &mu, g/mL. Results of this study suggest that interactions between polyphenols and BSA should be taken into account when evaluating procyanidin in an in vitro cell culture system.
- Published
- 2019
26. UBIAD1 Plays an Essential Role in the Survival of Pancreatic Acinar Cells
- Author
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Hiroshi Hasegawa, Chihiro Ichinose, Kanaha Kawamoto, Kiyomi Fujiwara, Yoshitomo Suhara, Chinami Murakami, Kimie Nakagawa, Toshio Okano, Akihiro Nishimura, and Yumi Kunitou
- Subjects
acinar cells ,Neutrophils ,Apoptosis ,Vacuole ,medicine.disease_cause ,lcsh:Chemistry ,Mice ,Adipocytes ,pancreas ,lcsh:QH301-705.5 ,Spectroscopy ,chemistry.chemical_classification ,Mice, Knockout ,tamoxifen ,Vitamin K2 ,General Medicine ,Immunohistochemistry ,Computer Science Applications ,Cell biology ,medicine.anatomical_structure ,Phenotype ,Neutrophil Infiltration ,Knockout mouse ,MK-4 ,Female ,Pancreas ,medicine.drug ,Genotype ,Cell Survival ,Biology ,Catalysis ,Article ,Cell Line ,Inorganic Chemistry ,medicine ,Autophagy ,Animals ,Physical and Theoretical Chemistry ,Molecular Biology ,Organic Chemistry ,Mesenchymal Stem Cells ,Dimethylallyltranstransferase ,Oxidative Stress ,Enzyme ,chemistry ,lcsh:Biology (General) ,lcsh:QD1-999 ,Genes, Lethal ,Atrophy ,UBIAD1 ,Oxidative stress ,Tamoxifen ,knockout mice - Abstract
UbiA prenyltransferase domain-containing protein 1 (UBIAD1) is a vitamin K2 biosynthetic enzyme. We previously showed the lethality of this enzyme in UBIAD1 knockout mice during the embryonic stage. However, the biological effects of UBIAD1 deficiency after birth remain unclear. In the present study, we used a tamoxifen-inducible systemic UBIAD1 knockout mouse model to determine the role of UBIAD1 in adult mice. UBIAD1 knockout resulted in the death of the mice within about 60 days of administration of tamoxifen. The pancreas presented with the most prominent abnormality in the tamoxifen-induced UBIAD1 knockout mice. The pancreas was reduced remarkably in size, furthermore, the pancreatic acinar cells disappeared and were replaced by vacuoles. Further analysis revealed that the vacuoles were adipocytes. UBIAD1 deficiency in the pancreatic acinar cells caused an increase in oxidative stress and autophagy, leading to apoptotic cell death in the tamoxifen-induced UBIAD 1 knockout mice. These results indicate that UBIAD1 is essential for maintaining the survival of pancreatic acinar cells in the pancreas.
- Published
- 2019
27. New Aspects of Vitamin K Research with Synthetic Ligands: Transcriptional Activity via SXR and Neural Differentiation Activity
- Author
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Yoshitomo Suhara and Yoshihisa Hirota
- Subjects
0301 basic medicine ,Vitamin ,Transcriptional Activation ,Vitamin K ,medicine.medical_treatment ,Neurogenesis ,Prenyltransferase ,Review ,030204 cardiovascular system & hematology ,Catalysis ,Steroid ,lcsh:Chemistry ,Inorganic Chemistry ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Menadione ,Neural Stem Cells ,neural differentiation action ,medicine ,Animals ,Humans ,steroid and xenobiotic receptor (SXR) ,Physical and Theoretical Chemistry ,lcsh:QH301-705.5 ,Molecular Biology ,Spectroscopy ,Chemistry ,Organic Chemistry ,Vitamin K2 ,Pregnane X Receptor ,Biological activity ,General Medicine ,Vitamins ,ã-glutamyl carboxylase (GGCX) ,Computer Science Applications ,Pyruvate carboxylase ,derivatives research ,030104 developmental biology ,lcsh:Biology (General) ,lcsh:QD1-999 ,Nuclear receptor ,Biochemistry ,UBIAD1 - Abstract
Vitamin K is classified into three homologs depending on the side-chain structure, with 2-methyl-1,4-naphthoqumone as the basic skeleton. These homologs are vitamin K1 (phylloquinone: PK), derived from plants with a phythyl side chain; vitamin K2 (menaquinone-n: MK-n), derived from intestinal bacteria with an isoprene side chain; and vitamin K3 (menadione: MD), a synthetic product without a side chain. Vitamin K homologs have physiological effects, including in blood coagulation and in osteogenic activity via γ-glutamyl carboxylase and are used clinically. Recent studies have revealed that vitamin K homologs are converted to MK-4 by the UbiA prenyltransferase domain-containing protein 1 (UBIAD1) in vivo and accumulate in all tissues. Although vitamin K is considered to have important physiological effects, its precise activities and mechanisms largely remain unclear. Recent research on vitamin K has suggested various new roles, such as transcriptional activity as an agonist of steroid and xenobiotic nuclear receptor and differentiation-inducing activity in neural stem cells. In this review, we describe synthetic ligands based on vitamin K and exhibit that the strength of biological activity can be controlled by modification of the side chain part.
- Published
- 2019
28. Front Cover: Development of Selective TGR5 Ligands Based on the 5,6,7,8‐Tetrahydro‐5,5,8,8‐tetramethylnaphthalene Skeleton (ChemMedChem 3/2021)
- Author
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Hidetomo Yokoo, Makoto Makishima, Yuta Yanase, Yosuke Demizu, Ryusei Terui, Yoshitomo Suhara, and Takashi Misawa
- Subjects
Pharmacology ,Front cover ,Stereochemistry ,Chemistry ,Organic Chemistry ,Drug Discovery ,Molecular Medicine ,General Pharmacology, Toxicology and Pharmaceutics ,Biochemistry ,Skeleton (computer programming) - Published
- 2021
29. Elucidation of the Interaction Between Flavan-3-ols and Protein in Digestive Fluid and its Effect on in Vitro Neurotoxicity
- Author
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Yusuke Sukikara, Fujii Yasuyuki, Naomi Osakabe, Yoshitomo Suhara, Yoshihisa Hirota, Kenjiro Yoshimura, and Tomohiro Teshima
- Subjects
chemistry.chemical_compound ,Biochemistry ,chemistry ,Flavan ,Physiology (medical) ,Neurotoxicity ,medicine ,medicine.disease ,In vitro - Published
- 2020
30. Synthesis and In Vitro Evaluation of Novel Liver X Receptor Agonists Based on Naphthoquinone Derivatives
- Author
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Yuki Ito, Makoto Makishima, Atsuko Takeuchi, Chisato Tode, Kaori Endo-Umeda, Yoshitomo Suhara, Yoshihisa Hirota, Tatsuma Nishioka, Naomi Osakabe, and Akane Shimoda
- Subjects
Agonist ,Transcription, Genetic ,Stereochemistry ,medicine.drug_class ,naphthoquinone ,Pharmaceutical Science ,Ligands ,01 natural sciences ,Article ,Pyrrolidine ,Cell Line ,Analytical Chemistry ,03 medical and health sciences ,chemistry.chemical_compound ,Menadione ,Morpholine ,Drug Discovery ,medicine ,Humans ,α-selective ,Physical and Theoretical Chemistry ,Receptor ,Liver X receptor ,agonist ,transcriptional activity ,Liver X Receptors ,030304 developmental biology ,0303 health sciences ,010405 organic chemistry ,liver X receptor (LXR) ,Organic Chemistry ,Naphthoquinone ,0104 chemical sciences ,HEK293 Cells ,chemistry ,Chemistry (miscellaneous) ,Docking (molecular) ,Molecular Medicine ,Naphthoquinones - Abstract
We aimed to synthesize novel liver X receptor (LXR) agonists with potent agonist activity and subtype selectivity. Our synthetic scheme started with naphthoquinone derivatives, such as menadione and 2,3-dichloro-1,4-naphthoquinone. We introduced different substituents into the naphthoquinone structures, including aniline, piperidine, pyrrolidine, and morpholine, in one or two steps, and thus, we produced 14 target compounds. All 14 synthetic ligands were tested to determine whether they mediated LXR-mediated transcriptional activity. We investigated the transcriptional activity of each compound with two types of receptors, LXR&alpha, and LXR&beta, Among all 14 compounds, two showed weak LXR&beta, agonist activity, and two others exhibited potent LXR&alpha, agonist activity. We also performed docking studies to obtain a better understanding of the modes of compound binding to LXR at the atomic level. In conclusion, we successfully synthesized naphthoquinone derivatives that act as LXR&alpha, /&beta, agonists and selective LXR&alpha, agonists.
- Published
- 2019
31. Eldecalcitol is more effective for promoting osteogenesis than alfacalcidol in Cyp27b1-knockout Mice
- Author
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Kimie Nakagawa, Keigo Isomoto, Maya Kamao, Toshiyuki Sakaki, Naomi Osakabe, Yoshitomo Suhara, Yoshihisa Hirota, Noboru Kubodera, and Toshio Okano
- Subjects
medicine.medical_specialty ,Osteoporosis ,Alfacalcidol ,Parathyroid hormone ,Eldecalcitol ,medicine.disease ,Calcitriol receptor ,Bone resorption ,chemistry.chemical_compound ,Endocrinology ,medicine.anatomical_structure ,chemistry ,Internal medicine ,medicine ,Vitamin D and neurology ,Cancellous bone - Abstract
Calcium (Ca) absorption from the intestinal tract is promoted by active vitamin D (1α,25D3). Vitamin D not only promotes Ca homeostasis, but it also inhibits bone resorption and promotes osteogenesis, thus playing a role in the maintenance of normal bone metabolism. Because 1α,25D3 plays an important role in osteogenesis, vitamin D formulations, such as alfacalcidol (ALF) and eldecalcitol (ELD), are used for treating osteoporosis. While it is known that, in contrast to ALF, ELD is an active ligand that directly acts on bone, the reason for its superior osteogenesis effects is unknown. Cyp27b1-knockout mice (Cyp27b1−/− mice) are congenitally deficient in 1α,25D3 and exhibit marked hypocalcemia and high parathyroid hormone levels, resulting in osteodystrophy involving bone hypocalcification and growth plate cartilage hypertrophy. However, because the vitamin D receptor is expressed normally in Cyp27b1−/− mice, they respond normally to 1α,25D3. Accordingly, in Cyp27b1−/− mice, the pharmacological effects of exogenously administered active vitamin D derivatives can be analyzed without being affected by 1α,25D3. We used Cyp27b1−/− mice to characterize and clarify the superior osteogenic effects of ELD on the bone in comparison with ALF. The results indicated that compared to ALF, ELD strongly induces ECaC2, calbindin-D9k, and CYP24A1 in the duodenum, promoting Ca absorption and decreasing the plasma concentration of 1α,25D3, resulting in improved osteogenesis. Because bone morphological measurements demonstrated that ELD has stronger effects on bone calcification, trabecular formation, and cancellous bone density than ALF, ELD appears to be a more effective therapeutic agent for treating postmenopausal osteoporosis, in which cancellous bone density decreases markedly. By using Cyp27b1−/− mice, this study was the first to succeed in clarifying the osteogenic effect of ELD without any influence of endogenous 1α,25D3. Furthermore, ELD more strongly enhanced bone mineralization, trabecular proliferation, and cancellous bone density than did ALF. Thus, ELD is expected to show an effect on postmenopausal osteoporosis, in which cancellous bone mineral density decreases markedly.
- Published
- 2018
32. Comparison of the sympathetic stimulatory abilities of B-type procyanidins based on induction of uncoupling protein-1 in brown adipose tissue (BAT) and increased plasma catecholamine (CA) in mice
- Author
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Toshiya Toda, Masaki Kamino, Naomi Osakabe, Yasuyuki Fujii, Yuta Nakagawa, Kana Ishimura, Satomi Oya, Yoshitomo Suhara, Fumio Nanba, Takeshi Ishii, and Takahiro Adachi
- Subjects
Male ,0301 basic medicine ,Physiology ,Administration, Oral ,Adipose tissue ,lcsh:Medicine ,Biochemistry ,chemistry.chemical_compound ,Catecholamines ,Adipose Tissue, Brown ,Brown adipose tissue ,Blood plasma ,Medicine and Health Sciences ,Amines ,lcsh:Science ,Procyanidin B2 ,Uncoupling Protein 1 ,Liquid Chromatography ,Mice, Inbred ICR ,Multidisciplinary ,Organic Compounds ,Ingestion ,Chromatographic Techniques ,Neurochemistry ,Neurotransmitters ,Thermogenin ,Body Fluids ,Yohimbine ,Chemistry ,Blood ,medicine.anatomical_structure ,Adipose Tissue ,Physical Sciences ,Seeds ,Brown Adipose Tissue ,Anatomy ,Research Article ,medicine.drug ,Procyanidin C1 ,Biogenic Amines ,medicine.medical_specialty ,Epinephrine ,Materials by Structure ,Materials Science ,Research and Analysis Methods ,Blood Plasma ,03 medical and health sciences ,Internal medicine ,medicine ,Animals ,Proanthocyanidins ,RNA, Messenger ,030102 biochemistry & molecular biology ,Organic Chemistry ,lcsh:R ,Chemical Compounds ,Biology and Life Sciences ,Hormones ,High Performance Liquid Chromatography ,Gastrointestinal Tract ,Biological Tissue ,030104 developmental biology ,Endocrinology ,Gene Expression Regulation ,chemistry ,Oligomers ,Catecholamine ,lcsh:Q ,Soybeans ,Physiological Processes ,Digestive System ,Neuroscience - Abstract
Objectives We previously found that elevated energy expenditure following a single oral dose of flavan 3-ols (FL), a mixture of catechins and B type procyanidins, is caused by sympathetic nerve activation. In the present study, we compared the activity of the FL components (-)-epicatechin (EC; monomer), procyanidin B2 (B2; dimer), procyanidin C1 (C1; trimer), cinnamtannin A2 (A2; tetramer), and more than pentamer fraction (P5). Methods Male ICR mice were treated with a single oral dose of FL, EC, B2, C1, A2, or P5. The animals were sacrificed and blood and brown adipose tissue (BAT) sampled. The plasma catecholamine (CA) levels and BAT uncoupling protein (UCP)-1 mRNA expression were determined. Results A single dose of 10 mg/kg FL significantly increased plasma CA and UCP-1 mRNA levels. B2, C1, and A2, but not EC and P5 (all at 1 mg/kg), significantly increased plasma adrenaline levels. Plasma noradrenaline was significantly elevated by B2 and A2, but not by EC, C1, or P5. UCP-1 mRNA levels were significantly increased by C1 and P5. In the dose response study of A2, 10−3 mg/kg A2 increased UCP-1 mRNA levels significantly, but not 10−2 and 10−1 mg/kg A2. In addition, combination treatment with 10−1 mg/kg A2 and yohimbine, an α2 adrenalin blocker, remarkably increased UCP-1 mRNA levels. Conclusion These results suggest that FL and its components, except EC, increase UCP-1 mRNA and plasma CA with varying efficacy.
- Published
- 2018
33. Synthetic Small Molecules Derived from Natural Vitamin K Homologues that Induce Selective Neuronal Differentiation of Neuronal Progenitor Cells
- Author
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Rie Sakane, Yoshitomo Suhara, Toshio Okano, Yoshihisa Hirota, Sachiko Eguchi, Shun Nishina, Akimori Wada, Kazuhiko Takahashi, Hiroaki Tokiwa, Kimie Nakagawa, and Norika Hanada
- Subjects
Neurons ,Chemistry ,Multipotent Stem Cells ,Cellular differentiation ,Vitamin K2 ,Cell Differentiation ,Neocortex ,Stereoisomerism ,Vitamin K 2 ,Small molecule ,Neural stem cell ,In vitro ,Mice ,Structure-Activity Relationship ,Neural Stem Cells ,Biochemistry ,Drug Discovery ,Animals ,Molecular Medicine ,Structure–activity relationship ,Progenitor cell - Abstract
We synthesized new vitamin K2 analogues with ω-terminal modifications of the side chain and evaluated their selective differentiation of neuronal progenitor cells into neurons in vitro. The result of the assay showed that the menaquinone-3 analogue modified with the m-methylphenyl group had the most potent activity, which was twice as great as the control. This finding indicated that it is possible to obtain much more potent compounds with modification of the structure of vitamin K2.
- Published
- 2015
34. YY1 positively regulates human UBIAD1 expression
- Author
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Yoshitomo Suhara, Toshio Okano, Yoshihisa Hirota, Masato Watanabe, Kimie Nakagawa, Natumi Sawada, and Nobuaki Funahashi
- Subjects
Chromatin Immunoprecipitation ,Small interfering RNA ,DNA, Complementary ,Transcription, Genetic ,Blotting, Western ,Molecular Sequence Data ,Biophysics ,Electrophoretic Mobility Shift Assay ,Biology ,Real-Time Polymerase Chain Reaction ,Biochemistry ,chemistry.chemical_compound ,Menadione ,Rapid amplification of cDNA ends ,Humans ,RNA, Messenger ,Promoter Regions, Genetic ,Molecular Biology ,Gene ,YY1 Transcription Factor ,Regulation of gene expression ,Messenger RNA ,Base Sequence ,Promoter ,Cell Biology ,Dimethylallyltranstransferase ,Molecular biology ,HEK293 Cells ,Gene Expression Regulation ,chemistry ,Chromatin immunoprecipitation ,Protein Binding - Abstract
Vitamin K is involved in bone formation and blood coagulation. Natural vitamin K compounds are composed of the plant form phylloquinone (vitamin K1) and a series of bacterial menaquionones (MK-n; vitamin K2). Menadione (vitamin K3) is an artificial vitamin K compound. MK-4 contains 4-isoprenyl as a side group in the 2-methyl-1,4-naphthoquinone common structure and has various bioactivities. UbiA prenyltransferase domain containing 1 (UBIAD1 or TERE1) is the menaquinone-4 biosynthetic enzyme. UBIAD1 transcript expression significantly decreases in patients with prostate carcinoma and overexpressing UBIAD1 inhibits proliferation of a tumour cell line. UBIAD1 mRNA expression is ubiquitous in mouse tissues, and higher UBIAD1 mRNA expression levels are detected in the brain, heart, kidneys and pancreas. Several functions of UBIAD1 have been reported; however, regulation of the human UBIAD1 gene has not been elucidated. Here we report cloning and characterisation of the human UBIAD1 promoter. A 5' rapid amplification of cDNA ends analysis revealed that the main transcriptional start site was 306 nucleotides upstream of the translation initiation codon. Deletion and mutation analyses revealed the functional importance of the YY1 consensus motif. Electrophoretic gel mobility shift and chromatin immunoprecipitation assays demonstrated that YY1 binds the UBIAD1 promoter in vitro and in vivo. In addition, YY1 small interfering RNA decreased endogenous UBIAD1 mRNA expression and UBIAD1 conversion activity. These results suggest that YY1 up-regulates UBIAD1 expression and UBIAD1 conversion activity through the UBIAD1 promoter.
- Published
- 2015
35. Nongenomic effects of 1α,25-dihydroxyvitamin D
- Author
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Yoshihisa, Hirota, Kimie, Nakagawa, Shino, Mimatsu, Natsumi, Sawada, Toshiyuki, Sakaki, Noboru, Kubodera, Maya, Kamao, Naoko, Tsugawa, Yoshitomo, Suhara, and Toshio, Okano
- Subjects
25-Hydroxyvitamin D3 1-alpha-Hydroxylase ,Male ,Mice, Knockout ,Body Weight ,Alopecia ,Cell Differentiation ,Phosphorus ,Real-Time Polymerase Chain Reaction ,Mice ,Cartilage ,Chondrocytes ,Phenotype ,Calcitriol ,Osteogenesis ,Parathyroid Hormone ,Animals ,Osteoporosis ,Receptors, Calcitriol ,Calcium ,Female ,Femur ,Cell Proliferation - Abstract
The active form of vitamin D, 1α,25-dihydroxyvitamin D
- Published
- 2016
36. Menadione (Vitamin K3) Is a Catabolic Product of Oral Phylloquinone (Vitamin K1) in the Intestine and a Circulating Precursor of Tissue Menaquinone-4 (Vitamin K2) in Rats
- Author
-
Atsuko Takeuchi, Yuri Uchino, Kiyoshi Tanaka, Yoshihisa Hirota, Natsumi Sawada, Kimie Nakagawa, Yoshitomo Suhara, Toshio Okano, Maya Kamao, Akimori Wada, Naoko Tsugawa, and Takashi Okitsu
- Subjects
Male ,Vitamin ,Prenyltransferase ,Biochemistry ,Rats, Sprague-Dawley ,Mice ,chemistry.chemical_compound ,Species Specificity ,Menadione ,Prenylation ,Animals ,Intestinal Mucosa ,Molecular Biology ,chemistry.chemical_classification ,Catabolism ,Vitamin K2 ,Vitamin K 3 ,Vitamin K 2 ,Vitamin K 1 ,Vitamins ,Cell Biology ,Metabolism ,Dimethylallyltranstransferase ,Lipids ,Recombinant Proteins ,Rats ,Enzyme ,chemistry ,Female - Abstract
Mice have the ability to convert dietary phylloquinone (vitamin K1) into menaquinone-4 (vitamin K2) and store the latter in tissues. A prenyltransferase enzyme, UbiA prenyltransferase domain-containing 1 (UBIAD1), is involved in this conversion. There is evidence that UBIAD1 has a weak side chain cleavage activity for phylloquinone but a strong prenylation activity for menadione (vitamin K3), which has long been postulated as an intermediate in this conversion. Further evidence indicates that when intravenously administered in mice phylloquinone can enter into tissues but is not converted further to menaquinone-4. These findings raise the question whether phylloquinone is absorbed and delivered to tissues in its original form and converted to menaquinone-4 or whether it is converted to menadione in the intestine followed by delivery of menadione to tissues and subsequent conversion to menaquinone-4. To answer this question, we conducted cannulation experiments using stable isotope tracer technology in rats. We confirmed that the second pathway is correct on the basis of structural assignments and measurements of phylloquinone-derived menadione using high resolution MS analysis and a bioassay using recombinant UBIAD1 protein. Furthermore, high resolution MS and (1)H NMR analyses of the product generated from the incubation of menadione with recombinant UBIAD1 revealed that the hydroquinone, but not the quinone form of menadione, was an intermediate of the conversion. Taken together, these results provide unequivocal evidence that menadione is a catabolic product of oral phylloquinone and a major source of tissue menaquinone-4.
- Published
- 2013
37. Structure-Activity Relationship of Novel Vitamin K Analogues as Steroid and Xenobiotic Receptor (SXR) Agonists
- Author
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Yoshihisa Hirota, Toshio Okano, Yoshitomo Suhara, Sayaka Motoyoshi, Natsumi Sawada, Hiroaki Tokiwa, and Kimie Nakagawa
- Subjects
Pharmacology ,Receptors, Steroid ,Vitamin K ,CYP3A4 ,Chemistry ,Stereochemistry ,medicine.medical_treatment ,Vitamin K2 ,Receptors, Cytoplasmic and Nuclear ,Pharmaceutical Science ,Ligands ,Xenobiotics ,Steroid ,Structure-Activity Relationship ,Nuclear receptor ,Downregulation and upregulation ,Transcription (biology) ,Constitutive androstane receptor ,medicine ,Side chain ,Humans - Abstract
Vitamin K2 is a ligand for a nuclear receptor, steroid and xenobiotic receptor (SXR), that induces the gene expressions of CYP3A4. We synthesized new vitamin K analogues with the same isoprene side chains symmetrically introduced at the 2 and 3 positions of 1,4-naphthoquinone and vitamin K2 analogues with hydroxyl or phenyl groups at the ω-terminal of the side chain. The upregulation of SXR-mediated transcription of the target gene by the analogues was dependent on the length of the side chain and the hydrophobicity of the ω-terminal residues. Phenyl analogue menaquinone-3 was as active as the known SXR ligand rifampicin.
- Published
- 2012
38. Structure–Activity Relationship of Novel Menaquinone-4 Analogues: Modification of the Side Chain Affects their Biological Activities
- Author
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Takashi Okitsu, Yoshitomo Suhara, Kazuhiko Takahashi, Toshio Okano, Masato Watanabe, Norika Hanada, Kimie Nakagawa, Miho Sakai, Kazuyoshi Takeda, Akimori Wada, and Hiroaki Tokiwa
- Subjects
Receptors, Steroid ,Transcription, Genetic ,Double bond ,Stereochemistry ,Plasma protein binding ,Structure-Activity Relationship ,chemistry.chemical_compound ,Genes, Reporter ,Transcription (biology) ,Cell Line, Tumor ,Drug Discovery ,Side chain ,Humans ,Structure–activity relationship ,Moiety ,Luciferases ,Demethylation ,chemistry.chemical_classification ,Pregnane X Receptor ,Vitamin K 2 ,Deuterium ,Retinoid X Receptors ,chemistry ,Molecular Medicine ,Protein Multimerization ,Protein Binding ,Methyl group - Abstract
We synthesized new vitamin K analogues with demethylation or reduction of the double bonds of the side chain of menaquinone-4 (MK-4) and evaluated their SXR-mediated transcriptional activity as well as the extent of their conversion to MK-4. The results indicated that the analogue with the methyl group deleted at the 7' site of the side chain part affected conversion activity to MK-4. In contrast, a decrease in the number of the double bonds in the side chain moiety appeared to decrease the SXR-mediated transcriptional activity.
- Published
- 2012
39. A single oral dose of flavan-3-ols enhances energy expenditure by sympathetic nerve stimulation in mice
- Author
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Naoya Kamio, Takuma Suzuki, Naomi Osakabe, Yuto Watanabe, and Yoshitomo Suhara
- Subjects
0301 basic medicine ,Male ,medicine.medical_specialty ,Sympathetic Nervous System ,Stimulation ,030204 cardiovascular system & hematology ,Biochemistry ,Butoxamine ,Propanolamines ,03 medical and health sciences ,0302 clinical medicine ,Adrenergic beta-2 Receptor Antagonists ,Physiology (medical) ,Internal medicine ,medicine ,Uncoupling protein ,Animals ,Receptor ,Protein kinase A ,Uncoupling Protein 1 ,Flavonoids ,Mice, Inbred ICR ,Chemistry ,AMPK ,Skeletal muscle ,Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha ,Thermogenin ,030104 developmental biology ,Endocrinology ,medicine.anatomical_structure ,Adrenergic beta-3 Receptor Antagonists ,Energy Metabolism - Abstract
Numerous clinical studies have found that ingestion of chocolate reduces the risk of metabolic syndrome, however, the mechanisms were remain unclear. We have reported that a single dose of a flavan-3-ol fraction derived from cocoa (FL) enhanced energy expenditure (EE) and increased the mRNA expression levels of uncoupling proteins (UCPs) and peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α), and the protein level of phosphorylated AMP-activated protein kinase (AMPK)α in tissues, along with plasma adrenaline level. In the present study, we examined whether the EE enhancing activity of FL is mediated by adrenergic effect using several adrenalin receptor (AR) blockers. In the first study, mice were butoxamine, as β2AR blocker, with vehicle or 10mg/kg FL orally. We found that pretreatment with butoxamine prevented the increases of EE, the mRNA expression of UCP-3, and phosphorylated AMPKα that were induced in the gastrocnemius muscle of mice by 10mg/kg FL. Secondly, mice were given SR52930, as β3AR blocker. Pretreatment with SR52930 prevented the increases of EE, the mRNA expression of UCP-3, and phosphorylated AMPKα that were induced in the gastrocnemius muscle of mice by 10mg/kg FL. Pretreatment with a combination of both blockers also reduced the increments in mRNA expression levels of UCPs and PGC-1α, however, phosphorylated AMPKα in skeletal muscle was rather increased. These results suggest that the ability of a single oral dose of FL to enhance metabolic activity is mediated by sympathetic nerve system (SNS).
- Published
- 2015
40. Synthesis of New Vitamin K Analogues as Steroid and Xenobiotic Receptor (SXR) Agonists: Insights into the Biological Role of the Side Chain Part of Vitamin K
- Author
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Masato Watanabe, Sayaka Motoyoshi, Kimie Nakagawa, Kazuhiko Takahashi, Toshio Okano, Kazuyoshi Takeda, Akimori Wada, Hiroaki Tokiwa, and Yoshitomo Suhara
- Subjects
Receptors, Steroid ,Vitamin K ,Transcription, Genetic ,medicine.medical_treatment ,Ligands ,Steroid ,Structure-Activity Relationship ,Hemiterpenes ,Genes, Reporter ,Pentanes ,Drug Discovery ,Gene expression ,Butadienes ,Side chain ,medicine ,Humans ,Structure–activity relationship ,Binding site ,Luciferases ,Receptor ,Pregnane X receptor ,Binding Sites ,Chemistry ,Vitamin K2 ,Pregnane X Receptor ,Hep G2 Cells ,Biochemistry ,Molecular Medicine - Abstract
Vitamin K(2) has been demonstrated to induce gene expression related to bone formation through a nuclear steroid and xenobiotic receptor (SXR). We synthesized new vitamin K analogues with the same isoprene side chains symmetrically introduced at the 2 and 3 positions of 1,4-naphthoquinone and evaluated the transcriptional activity of the target gene. The transcriptional activity was related to the length of the side chain which allowed optimal interaction with ligand-binding domain of SXR.
- Published
- 2011
41. Synthesis of Novel Vitamin K2 Analogues with Modification at the ω-Terminal Position and Their Biological Evaluation as Potent Steroid and Xenobiotic Receptor (SXR) Agonists
- Author
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Kazuyoshi Takeda, Yoichi Ito, Masato Watanabe, Yoshitomo Suhara, Kazuhiko Takahashi, Akimori Wada, Kimie Nakagawa, and Toshio Okano
- Subjects
Models, Molecular ,Receptors, Steroid ,Pregnane X receptor ,Transcription, Genetic ,CYP3A4 ,Chemistry ,Stereochemistry ,Ligand ,medicine.medical_treatment ,Pregnane X Receptor ,Vitamin K 2 ,Hep G2 Cells ,Ligands ,Steroid ,Structure-Activity Relationship ,Nuclear receptor ,Biochemistry ,Drug Discovery ,Side chain ,medicine ,Humans ,Molecular Medicine ,Structure–activity relationship ,Luciferases ,Receptor - Abstract
Vitamin K(2) is a ligand for a nuclear receptor, steroid and xenobiotic receptor (SXR), that induces the gene expressions of CYP3A4. We synthesized vitamin K(2) analogues with hydroxyl or phenyl groups at the ω-terminal of the side chain. The up-regulation of SXR-mediated transcription of the target gene by the analogues was dependent on the length of the side chain and the hydrophobicity of the ω-terminal residues. Phenyl analogue menaquinone-3 was as active as the known SXR ligand rifampicin.
- Published
- 2011
42. Identification of UBIAD1 as a novel human menaquinone-4 biosynthetic enzyme
- Author
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Yoshitomo Suhara, Masato Watanabe, Yoshihisa Hirota, Naohito Yuge, Yuri Uchino, Naoko Okuda, Yuka Shimomura, Kimie Nakagawa, Toshio Okano, and Natsumi Sawada
- Subjects
Small interfering RNA ,Vitamin K ,Prenyltransferase ,Spodoptera ,Biology ,Bone and Bones ,Cell Line ,Mice ,chemistry.chemical_compound ,Prenylation ,Menadione ,Biosynthesis ,Animals ,Humans ,RNA, Small Interfering ,chemistry.chemical_classification ,Osteoblasts ,Multidisciplinary ,Endoplasmic reticulum ,Proteins ,Vitamin K 2 ,Vitamin K 1 ,Dimethylallyltranstransferase ,Magnetic Resonance Imaging ,Enzyme ,chemistry ,Biochemistry ,Cell culture ,Warfarin ,Baculoviridae - Abstract
Vitamin K occurs in the natural world in several forms, including a plant form, phylloquinone (PK), and a bacterial form, menaquinones (MKs). In many species, including humans, PK is a minor constituent of hepatic vitamin K content, with most hepatic vitamin K content comprising long-chain MKs. Menaquinone-4 (MK-4) is ubiquitously present in extrahepatic tissues, with particularly high concentrations in the brain, kidney and pancreas of humans and rats. It has consistently been shown that PK is endogenously converted to MK-4 (refs 4-8). This occurs either directly within certain tissues or by interconversion to menadione (K(3)), followed by prenylation to MK-4 (refs 9-12). No previous study has sought to identify the human enzyme responsible for MK-4 biosynthesis. Previously we provided evidence for the conversion of PK and K(3) into MK-4 in mouse cerebra. However, the molecular mechanisms for these conversion reactions are unclear. Here we identify a human MK-4 biosynthetic enzyme. We screened the human genome database for prenylation enzymes and found UbiA prenyltransferase containing 1 (UBIAD1), a human homologue of Escherichia coli prenyltransferase menA. We found that short interfering RNA against the UBIAD1 gene inhibited the conversion of deuterium-labelled vitamin K derivatives into deuterium-labelled-MK-4 (MK-4-d(7)) in human cells. We confirmed that the UBIAD1 gene encodes an MK-4 biosynthetic enzyme through its expression and conversion of deuterium-labelled vitamin K derivatives into MK-4-d(7) in insect cells infected with UBIAD1 baculovirus. Converted MK-4-d(7) was chemically identified by (2)H-NMR analysis. MK-4 biosynthesis by UBIAD1 was not affected by the vitamin K antagonist warfarin. UBIAD1 was localized in endoplasmic reticulum and ubiquitously expressed in several tissues of mice. Our results show that UBIAD1 is a human MK-4 biosynthetic enzyme; this identification will permit more effective decisions to be made about vitamin K intake and bone health.
- Published
- 2010
43. Structure–activity relationships in the conversion of vitamin K analogues into menaquinone-4. Substrates essential to the synthesis of menaquinone-4 in cultured human cell lines
- Author
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Masato Watanabe, Kanae Nakamura, Kimie Nakagawa, Yoji Tachibana, Toshio Okano, Yoshitomo Suhara, and Akimori Wada
- Subjects
Vitamin K ,Double bond ,Stereochemistry ,Clinical Biochemistry ,Pharmaceutical Science ,Biochemistry ,Chemical synthesis ,Hemostatics ,Mass Spectrometry ,Cell Line ,Substrate Specificity ,Structure-Activity Relationship ,Cell Line, Tumor ,Drug Discovery ,Side chain ,Humans ,Structure–activity relationship ,Molecular Biology ,Chromatography, High Pressure Liquid ,chemistry.chemical_classification ,Molecular Structure ,Chemistry ,Organic Chemistry ,Vitamin K 2 ,In vitro ,Quinone ,Enzyme ,Cell culture ,Molecular Medicine - Abstract
To reveal an essential biological role of menaquinone-4, we have clarified that dietary PK was converted to menaquinone-4 (MK-4) in animal tissues using deuterated vitamin K analogues. However, the kinds of analogue converted into MK-4 have not been elucidated. In this study, we examined structure-activity relationships in the conversion of several vitamin K analogues, with a substituted side chain, into MK-4 using cultured human cell lines. The results differed with the side chain of the analogues, that is, (1) the length of the isoprene unit and (2) the number of double bonds in the side chain. These findings would be useful for clarifying the mechanism of conversion of other vitamin K homologs into MK-4 as well as related enzymes.
- Published
- 2010
44. Synthesis and development of biologically active fluorescent-labeled vitamin K analogues and monitoring of their subcellular distribution
- Author
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Maya Kamao, Naoko Tsugawa, Kimie Nakagawa, Shinya Abe, Yuka Shimomura, Yoshitomo Suhara, Toshio Okano, and Aya Murakami
- Subjects
Vitamin ,Organic Chemistry ,Biological activity ,Metabolism ,Vitamin k ,Biochemistry ,Fluorescence ,Naphthoquinone ,Subcellular distribution ,chemistry.chemical_compound ,chemistry ,Drug Discovery ,Peptide bond - Abstract
New fluorescent analogues of menaquinone-4 and phylloquinone were prepared and their subcellular distribution monitored using a confocal laser scanning microscope. These analogues incorporate an FITC group anchored to the naphthoquinone skeleton through an amide bond expected to be resistant to metabolism. On their addition to the culture medium, fluorescence was readily observed inside a human osteosarcoma cell line. This result indicates that the fluorescent analogues penetrate into cells the same as vitamin K, and therefore, would be useful for achieving insight into the action mechanism of vitamin K.
- Published
- 2008
45. Conversion of Phylloquinone (Vitamin K1) into Menaquinone-4 (Vitamin K2) in Mice
- Author
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Maya Kamao, Kimie Nakagawa, Makiko Yamane, Yuka Shimomura, Makiko Sugiura, Yoshitomo Suhara, and Toshio Okano
- Subjects
Vitamin ,Vitamin K2 ,Phylloquinone intake ,Cell Biology ,Vitamin k ,Biochemistry ,Enteral administration ,Dietary vitamin ,chemistry.chemical_compound ,chemistry ,Menadione ,Prenylation ,Molecular Biology - Abstract
There are two forms of naturally occurring vitamin K, phylloquinone and the menaquinones. Phylloquinone (vitamin K1) is a major type (>90%) of dietary vitamin K, but its concentrations in animal tissues are remarkably low compared with those of the menaquinones, especially menaquinone-4 (vitamin K2), the major form (>90%) of vitamin K in tissues. Despite this great difference, the origin of tissue menaquinone-4 has yet to be exclusively defined. It is postulated that phylloquinone is converted into menaquinone-4 and accumulates in extrahepatic tissues. To clarify this, phylloquinone with a deuterium-labeled 2-methyl-1,4-naphthoquinone ring was given orally to mice, and cerebra were collected for D NMR and liquid chromatography-tandem mass spectrometry analyses. We identified the labeled menaquinone-4 that was converted from the given phylloquinone, and this conversion occurred following an oral or enteral administration, but not parenteral or intracerebroventricular administration. By the oral route, the phylloquinone with the deuterium-labeled side chain in addition to the labeled 2-methyl-1,4-naphthoquinone was clearly converted into a labeled menaquinone-4 with a non-deuterium-labeled side chain, implying that phylloquinone was converted into menaquinone-4 via integral side-chain removal. The conversion also occurred in cerebral slice cultures and primary cultures. Deuterium-labeled menadione was consistently converted into the labeled menaquinone-4 with all of the administration routes and the culture conditions tested. Our results suggest that cerebral menaquinone-4 originates from phylloquinone intake and that there are two routes of accumulation, one is the release of menadione from phylloquinone in the intestine followed by the prenylation of menadione into menaquinone-4 in tissues, and another is cleavage and prenylation within the cerebrum.
- Published
- 2008
46. Functional characterization of the vitamin K2 biosynthetic enzyme UBIAD1
- Author
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Natsumi Sawada, Toshio Okano, Yuri Uchino, Naoko Okuda, Naoko Tsugawa, Maya Kamao, Yoshihisa Hirota, Kimie Nakagawa, Yoshitomo Suhara, Nobuaki Funahashi, and Takashi Kimoto
- Subjects
Insecta ,Molecular Sequence Data ,Protein domain ,Protein Prenylation ,Gene Expression ,Mevalonic Acid ,lcsh:Medicine ,Sequence alignment ,Biology ,Cell Line ,chemistry.chemical_compound ,Prenylation ,EVH1 domain ,Dimethylallyltranstransferase ,Microsomes ,Animals ,Humans ,Point Mutation ,Amino Acid Sequence ,Binding site ,lcsh:Science ,Multidisciplinary ,Geranyl pyrophosphate ,lcsh:R ,Vitamin K 2 ,Biosynthetic Pathways ,Protein Structure, Tertiary ,Cholesterol ,Biochemistry ,chemistry ,Protein prenylation ,lcsh:Q ,Sequence Alignment ,Research Article - Abstract
UbiA prenyltransferase domain-containing protein 1 (UBIAD1) plays a significant role in vitamin K2 (MK-4) synthesis. We investigated the enzymological properties of UBIAD1 using microsomal fractions from Sf9 cells expressing UBIAD1 by analysing MK-4 biosynthetic activity. With regard to UBIAD1 enzyme reaction conditions, highest MK-4 synthetic activity was demonstrated under basic conditions at a pH between 8.5 and 9.0, with a DTT ≥0.1 mM. In addition, we found that geranyl pyrophosphate and farnesyl pyrophosphate were also recognized as a side-chain source and served as a substrate for prenylation. Furthermore, lipophilic statins were found to directly inhibit the enzymatic activity of UBIAD1. We analysed the aminoacid sequences homologies across the menA and UbiA families to identify conserved structural features of UBIAD1 proteins and focused on four highly conserved domains. We prepared protein mutants deficient in the four conserved domains to evaluate enzyme activity. Because no enzyme activity was detected in the mutants deficient in the UBIAD1 conserved domains, these four domains were considered to play an essential role in enzymatic activity. We also measured enzyme activities using point mutants of the highly conserved aminoacids in these domains to elucidate their respective functions. We found that the conserved domain I is a substrate recognition site that undergoes a structural change after substrate binding. The conserved domain II is a redox domain site containing a CxxC motif. The conserved domain III is a hinge region important as a catalytic site for the UBIAD1 enzyme. The conserved domain IV is a binding site for Mg2+/isoprenyl side-chain. In this study, we provide a molecular mapping of the enzymological properties of UBIAD1.
- Published
- 2015
47. Comparative uptake, metabolism, and utilization of menaquinone-4 and phylloquinone in human cultured cell lines
- Author
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Toshio Okano, Aya Murakami, Yukari Mizuguchi, Kimie Nakagawa, and Yoshitomo Suhara
- Subjects
Vitamin ,Vitamin K ,Clinical Biochemistry ,Pharmaceutical Science ,Epoxide ,Biochemistry ,Mass Spectrometry ,Cell Line ,chemistry.chemical_compound ,In vivo ,Cell Line, Tumor ,Drug Discovery ,medicine ,Humans ,Molecular Biology ,Chromatography, High Pressure Liquid ,Organic Chemistry ,Vitamin K 2 ,Vitamin K 1 ,Metabolism ,Reference Standards ,In vitro ,Quinone ,medicine.anatomical_structure ,chemistry ,Cell culture ,Hepatocyte ,Calibration ,Molecular Medicine ,Indicators and Reagents - Abstract
It is generally accepted that the availability of vitamin K in vivo depends on its homologues, the biological activities of which would differ among organs. To test this hypothesis, we examined the uptake, metabolism, and utilization of menaquinone-4 (MK-4) and phylloquinone (PK) using 18O-labeled compounds in two cultured human cell lines (HepG2 and MG-63). Lipid extracts were prepared from the cells and media after 1, 3, and 6h of incubation. The detection of the vitamin K analogues (18O-, 16O-quinone, and epoxide forms) was carried out with LC-APCI-MS/MS as previously reported. The 18O of vitamin K was replaced with atmospheric 16O2 during the formation of vitamin K epoxide with a carboxylative catalytic reaction. As a result, a significant difference was observed between MK-4 and PK in the amounts taken up into the cells. The 18O-labeled MK-4 was rapidly and remarkably well absorbed into the cells and metabolized to the epoxide form via a hydroquinone form as compared to the 18O-labeled PK. The difference in uptake of MK-4 and PK was not affected by treatment with warfarin although the metabolism of both compounds was markedly inhibited. This methodology should be utilized to clarify some of the actions of vitamin K in target cells and facilitate the development of new vitamin K drugs.
- Published
- 2006
48. Efficient synthesis of carbopeptoid oligomers: insight into mimicry of β-peptide
- Author
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Atsushi Kittaka, Yoshitomo Suhara, Yoshitaka Ichikawa, and Masaaki Kurihara
- Subjects
chemistry.chemical_classification ,Molecular model ,Stereochemistry ,Organic Chemistry ,Glycosidic bond ,Peptide ,BOP reagent ,Polysaccharide ,Biochemistry ,chemistry.chemical_compound ,chemistry ,Glucosamine ,Amide ,Drug Discovery ,Derivative (chemistry) - Abstract
The ready access to a new class of carbohydrate mimetics was demonstrated by the synthesis of tetrameric carbopeptoids, in which glycosidic bonds were replaced with amide linkages. We herein describe the detailed synthetis method of β(1→2)- and β(1→6)-linked carbopeptoids starting from each d -glucosamine and d -glucose derivative. The building blocks were polymerized using BOP reagent and DIEA to form a homooligomer. These produced carbopeptoids are resistant to glycosidases and have interesting biological activity. With conformational analysis by molecular modeling calculation, β(1→2)-linked decamer showed a typical 16-helix form as a mimic of β-peptide. Therefore, our polysaccharide analogues have potential as peptide foldamers.
- Published
- 2006
49. Vitamin K status of healthy Japanese women: age-related vitamin K requirement for γ-carboxylation of osteocalcin
- Author
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Maya Kamao, Masataka Shiraki, Yoshitomo Suhara, Kiyoshi Tanaka, Naoko Tsugawa, and Toshio Okano
- Subjects
Adult ,Aging ,medicine.medical_specialty ,Deoxypyridinoline ,Vitamin K ,Osteocalcin ,Carboxylic Acids ,Nutritional Status ,Medicine (miscellaneous) ,Bone and Bones ,Bone remodeling ,Fractures, Bone ,chemistry.chemical_compound ,Japan ,N-terminal telopeptide ,Bone Density ,Risk Factors ,Internal medicine ,Vitamin K deficiency ,Blood plasma ,medicine ,Humans ,Aged ,Aged, 80 and over ,Bone mineral ,Nutrition and Dietetics ,biology ,Chemistry ,Age Factors ,Nutritional Requirements ,Vitamin K 2 ,Vitamin K 1 ,Vitamins ,Bone fracture ,Middle Aged ,medicine.disease ,Endocrinology ,biology.protein ,Female ,Vitamin K Deficiency ,Biomarkers - Abstract
Background Vitamin K deficiency is associated with low bone mineral density and increased risk of bone fracture. Phylloquinone (K1) and menaquinone 4 (MK-4) and 7 (MK-7) are generally observed in human plasma; however, data are limited on their circulating concentrations and their associations with bone metabolism or with gamma-carboxylation of the osteocalcin molecule. Objectives The objectives were to measure the circulating concentrations of K1, MK-4, and MK-7 in women and to ascertain whether each form of vitamin K is significantly associated with bone metabolism. Design Plasma concentrations of K1, MK-4, MK-7, undercarboxylated osteocalcin (ucOC; measured by using the new electrochemiluminescence immunoassay), intact osteocalcin (iOC), calcium, and phosphorus; bone-derived alkaline phosphatase activity; and concentrations of urinary creatinine, N-terminal telopeptide, and deoxypyridinoline were measured in healthy women (n = 396). Results On average, MK-7 and MK-4 were the highest and lowest, respectively, of the 3 vitamers in all age groups. K1 and MK-7 correlated inversely with ucOC, but associations between nutritional basal concentration of MK-4 and ucOC were not observed. Multiple regression analysis indicated that not only K1 and MK-7 concentrations but also age were independently correlated with ucOC concentration and the ratio of ucOC to iOC. The plasma K1 or MK-7 concentration required to minimize the ucOC concentration was highest in the group aged > or =70 y, and it decreased progressively for each of the younger age groups. Conclusions The definite role of ucOC remains unclear. However, if submaximal gamma-carboxylation is related to the prevention of fracture or bone mineral loss, circulating vitamin K concentrations in elderly people should be kept higher than those in young people.
- Published
- 2006
50. METABOLISM OF 2α-PROPOXY-1α,25-DIHYDROXYVITAMIN D3AND 2α-(3-HYDROXYPROPOXY)-1α,25-DIHYDROXYVITAMIN D3BY HUMAN CYP27A1 AND CYP24A1
- Author
-
Yoshitomo Suhara, Toshiyuki Sakaki, Masaki Kamakura, Toshie Fujishima, Daisuke Abe, Hiroaki Takayama, Hiromi Hamamoto, Nozomi Saito, Miho Ohta, Atsushi Kittaka, Kuniyo Inouye, and Tatsuya Kusudo
- Subjects
Pharmacology ,Vitamin ,medicine.medical_specialty ,Pharmaceutical Science ,chemistry.chemical_element ,Vitamin D3 24-Hydroxylase ,Biological activity ,Metabolism ,Calcium ,Calcitriol receptor ,chemistry.chemical_compound ,Endocrinology ,CYP24A1 ,Biochemistry ,chemistry ,Internal medicine ,medicine ,Enzyme kinetics - Abstract
Recently, we demonstrated that some A-ring-modified vitamin D3 analogs had unique biological activity. Of these analogs, 2alpha-propoxy-1alpha,25(OH)2D3 (C3O1) and 2alpha-(3-hydroxypropoxy)-1alpha,25(OH)2D3 (O2C3) were examined for metabolism by CYP27A1 and CYP24A1. Surprisingly, CYP27A1 catalyzed the conversion from C3O1 to O2C3, which has 3 times more affinity for vitamin D receptor than C3O1. Thus, the conversion from C3O1 to O2C3 by CYP27A1 is considered to be a metabolic activation process. Five metabolites were detected in the metabolism of C3O1 and O2C3 by human CYP24A1 including both C-23 and C-24 oxidation pathways. On the other hand, three metabolites of the C-24 oxidation pathway were detected in their metabolism by rat CYP24A1, indicating a species-based difference in the CYP24A1-dependent metabolism of C3O1 and O2C3 between humans and rats. Kinetic analysis revealed that the Km and kcat values of human CYP24A1 for O2C3 are, respectively, approximately 16 times more and 3 times less than those for 1alpha,25(OH)2D3. Thus, the catalytic efficiency, kcat/Km, of human CYP24A1 for O2C3 is only 2% of 1alpha,25(OH)2D3. These results and a high calcium effect of C3O1 and O2C3 in animal experiments using rats suggest that C3O1 and O2C3 are promising for clinical treatment of osteoporosis.
- Published
- 2005
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