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The construction of a chemical library based on natural products is a promising method for the synthesis of natural product-like compounds. In this study, we synthesized a terpenoid alkaloid-like compound library based on the humulene skeleton. Our strategy, which enables access to diverse ring systems such as 11-membered monocyclic, oxabicyclic, and medium-sized aza ring-containing scaffolds, involves the introduction of a nitrogen atom, an intermolecular C-O bond formation via Lewis acid-mediated epoxide-opening transannulation, and a ring-reconstruction strategy based on olefin metathesis. A cheminformatics analysis based on their structural and physicochemical properties revealed that the synthesized compounds have high three-dimensionality and high natural product likeness scores but with structural novelty. The usefulness of the terpenoid alkaloid-like compound library for drug discovery and the accessibility to structure-activity relationship studies were validated by performing an assay for osteoclast-specific tartrate-resistant acid phosphatase activity, resulting in the identification of a seed compound for bone-resorptive diseases such as osteoporosis.
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Electron channeling contrast imaging (ECCI) was applied by precisely controlling the primary electron beam incident direction of the crystal plane in scanning electron microscope (SEM), and the dislocation contrast in steel materials was investigated in detail via SEM/ECCI. The dislocation contrast was observed near a channeling condition, where the incident electron beam direction of the crystal plane varied, and the backscattered electron intensity reached a local minimum. Comparing the dislocation contrasts in the visualized electron channeling contrast (ECC) images and transmission electron microscope (TEM) images, the positions of all dislocation lines were coincident. During the SEM/ECCI observation, the dislocation contrast varied depending on the incident electron beam direction of the crystal plane and accelerating voltages, and optimal conditions existed. When the diffraction condition g and the Burgers vector b of dislocation satisfied the condition g⸱b = 0, the screw dislocation contrast in the ECC image disappeared. An edge dislocation line was wider than a screw dislocation line. Thus, the SEM/ECCI method can be used for dislocation characterization and the strain field evaluation around dislocation, like the TEM method. The depth information of SEM/ECCI, where the channeling condition is strictly satisfied, can be obtained from dislocation contrast deeper than 5ξg, typically used for depth of SEM/ECCI.
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Propolis is a honeybee product with various biological activities, including antidiabetic effects. We previously reported that artepillin C, a prenylated cinnamic acid derivative isolated from Brazilian green propolis, acts as a peroxisome proliferator-activated receptor γ (PPARγ) ligand and promotes adipocyte differentiation. In this study, we examined the effect of baccharin, another major component of Brazilian green propolis, on adipocyte differentiation. The treatment of mouse 3T3-L1 preadipocytes with baccharin resulted in increased lipid accumulation, cellular triglyceride levels, glycerol-3-phosphate dehydrogenase activity, and glucose uptake. The mRNA expression levels of PPARγ and its target genes were also increased by baccharin treatment. Furthermore, baccharin enhanced PPARγ-dependent luciferase activity, suggesting that baccharin promotes adipocyte differentiation via PPARγ activation. In diabetic ob/ob mice, intraperitoneal administration of 50 mg/kg baccharin significantly improved blood glucose levels. Our results suggest that baccharin has a hypoglycemic effect on glucose metabolic disorders, such as type 2 diabetes mellitus.
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Adipocitos/metabolismo , Hiperglucemia/metabolismo , Própolis/química , Animales , Diferenciación Celular/genética , Diferenciación Celular/fisiología , Glicerolfosfato Deshidrogenasa/genética , Glicerolfosfato Deshidrogenasa/metabolismo , Hiperglucemia/genética , RatonesRESUMEN
Skeletal muscle is a major tissue of glucose consumption and plays an important role in glucose homeostasis. Prenylflavonoids, a component of Macaranga tanarius fruits, have been reported to have antioxidant, antibacterial, and anticancer effects. However, the effects of these compounds on skeletal muscle glucose metabolism are unclear. Here, we isolated five prenylflavonoids from M. tanarius fruits, and investigated the mechanism of action of these compounds on skeletal muscle cells using L6 myotubes. We found that isonymphaeol B and 3'-geranyl naringenin increased glucose uptake in a dose-dependent manner. Furthermore, both isonymphaeol B and 3'-geranyl naringenin increased AMPK phosphorylation but did not affect PI3K-Akt phosphorylation. Isonymphaeol B and 3'-geranyl naringenin also increased Glut1 mRNA expression and plasma membrane GLUT1 protein levels. These results suggest that isonymphaeol B and 3'-geranyl naringenin have beneficial effects on glucose metabolism through AMPK and GLUT1 pathway. Isonymphaeol B and 3'-geranyl naringenin may be potential lead candidates for antidiabetic drug development.
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Proteínas Quinasas Activadas por AMP , Euphorbiaceae , Proteínas Quinasas Activadas por AMP/genética , Proteínas Quinasas Activadas por AMP/metabolismo , Euphorbiaceae/metabolismo , Frutas , Glucosa/metabolismo , Transportador de Glucosa de Tipo 4/genética , Transportador de Glucosa de Tipo 4/metabolismo , Insulina/metabolismo , Fibras Musculares Esqueléticas , Músculo Esquelético/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , FosforilaciónRESUMEN
The cAMP-response element (CRE) is critical in the formation of long-term memory. To prove the pharmacological effects of the methoxyflavones-rich residue (MRR) and its constituent methoxyflavones (1-9) extracted from the rhizomes of Kaempferia parviflora on the nervous system, we examined the effects of the MRR and methoxyflavones (1-9) on CRE-mediated transcription in PC12D cells. The MRR increased CRE-mediated transcription in PC12D cells. In addition, among methoxyflavones (1-9) isolated from MRR, compounds 1-4 increased CRE-mediated transcription. These results suggest that K. parviflora and methoxyflavone might be very useful materials for preventing and recovering from cognitive decline.
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Flavonas/farmacología , Transcripción Genética/efectos de los fármacos , Zingiberaceae/química , Animales , Supervivencia Celular/efectos de los fármacos , Flavonas/aislamiento & purificación , Flavonas/toxicidad , Estructura Molecular , Células PC12 , Extractos Vegetales/aislamiento & purificación , Extractos Vegetales/farmacología , Extractos Vegetales/toxicidad , Ratas , Elementos de Respuesta/fisiología , Relación Estructura-ActividadRESUMEN
Bone mass is regulated by osteoblast-mediated bone formation and osteoclast-mediated bone resorption. Osteoporosis is a bone metabolism disorder in which bone mass decreases due to increased bone resorption rather than bone formation. We focused on the traditional plant Alpinia zerumbet in Okinawa, Japan, and searched for promising compounds for the prevention and treatment of osteoporosis. Pinocembrin isolated from the leaves of A. zerumbet showed enhanced alkaline phosphatase (ALP) activity and mineralization and increased mRNA expression of osteoblast-related genes Alp and Osteocalcin (Ocn) in MC3T3-E1 cells. Pinocembrin increased the mRNA expression of Runx2 and Osterix, which are important transcription factors in osteoblast differentiation, and the mRNA expression of Dlx5 and Msx2, which are enhancers of these transcription factors. The bone morphogenetic protein (BMP) antagonist noggin, its receptor kinase inhibitor LDN-193189 and p38 MAPK inhibitor SB203580 attenuated pinocembrin-promoted ALP activity. Pinocembrin increased the mRNA of Bmp-2 and its target gene Id1. In addition, the estrogen receptor (ER) inhibitor ICI182780 suppressed pinocembrin-stimulated ALP activity. Pinocembrin may increase BMP-2 expression via ER. Then, the BMP-2 promotes osteoblast specific genes expression and mineralization through both Smad-dependent and independent pathway following Runx2 and Osterix induction. Our findings suggest that pinocembrin has bone anabolic effects and may be useful for the prevention and treatment of bone metabolic diseases such as osteoporosis.
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BACKGROUND AND AIMS: Nobiletin (NOB), a functional ingredient found in citrus peel, is said to act against diabetes, obesity, and atherosclerosis. It has been reported to activate AMPK pathway, as well as increase SREBP1c, PPARα and PPARγ expression. However, no molecular mechanism has been elucidated to be able to integrate these sporadic findings with some controversies to lead to concrete outcomes. In this study, regulation of HDL biogenesis by NOB was investigated modulating ABCA1 and ABCG1 expression. METHODS AND RESULTS: Regulation of ABCA1/G1 by NOB was investigated in mouse macrophages J774.1. NOB increased mRNA and protein levels of ABCA1/G1, and cell cholesterol release by these factors. It also increased mRNA of PPARγ and LXRα but not PPARα. The increase in ABCA1/G1 mRNA levels by NOB was suppressed by antagonists of PPARγ and LXRα. The increase in PPARγ mRNA levels by NOB was suppressed by an LXRα antagonist, and the increase in LXRα mRNA levels was suppressed by a PPARγ antagonist. NOB increased CD36 mRNA and this was suppressed by an LXRα antagonist. The increase in ABCA1 mRNA by a PPARγ agonist was also suppressed by an LXRα antagonist. NOB did not influence LPL1 mRNA expression levels. NOB stimulated AMPK phosphorylation, and the increase in ABCA1/G1, LXRα and PPARγ mRNA levels and ABCA1/G1 protein levels by NOB was reversed by an AMPK inhibitor. AMPK siRNA suppressed ABCA1 expression. CONCLUSIONS: NOB activates AMPK and subsequently LXRα to promote the expression of ABCA1 and ABCG1, and an LXRα - PPARγ loop pathway amplifies these signals.
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Transportador 1 de Casete de Unión a ATP/metabolismo , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 1/metabolismo , Flavonas/farmacología , Hipolipemiantes/farmacología , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Proteínas Quinasas Activadas por AMP/metabolismo , Transportador 1 de Casete de Unión a ATP/genética , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 1/genética , Animales , Línea Celular , Activación Enzimática , Receptores X del Hígado/genética , Receptores X del Hígado/metabolismo , Ratones , PPAR gamma/genética , PPAR gamma/metabolismo , Fosforilación , Regulación hacia ArribaRESUMEN
Thymic stromal lymphopoietin (TSLP) is a key epithelial-derived factor that aggravates allergic diseases. Therefore, TSLP inhibitors are candidate compounds for the treatment of allergic diseases. Previously, we reported that KCMH-1, a mouse keratinocyte cell line, constitutively produces TSLP. In this study, we tried to identify inhibitors of TSLP by screening 2169 compounds in KCMH-1 cells and found one such chalcone derivative (code no. 16D10). 16D10 inhibited TSLP expression and TSLP promoter activation in HaCaT cells, a human keratinocyte cell line. Although nuclear factor kappa-B (NF-κB) is a key transcription factor for the induction of TSLP, 16D10 did not inhibit the activation pathway of NF-κB, such as degradation of inhibitor of κB (IκB) and p65 nuclear translocation. 16D10 activated the Kelch-like ECH-associated protein 1 (Keap1)-nuclear factor (erythroid-derived 2)-like 2 (Nrf2) system, although this system was not involved in the inhibitory effect of 16D10. 16D10 also inhibited TSLP production in a lipopolysaccharide (LPS)- or ovalbumin (OVA)-induced air-pouch-type inflammation model. Further, repeated 16D10 administration diminished serum immunoglobulin G1 (IgG1) and IgE concentration in an OVA-induced air-pouch-type sensitization model. Taken together, these results indicate that 16D10 is an inhibitor of TSLP production and has an anti-allergic effect. This inhibitory effect is independent of the activation of NF-κB and the Keap1-Nrf2 system. Therefore, 16D10 could be a new type of candidate drug for allergic diseases.
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Formación de Anticuerpos/efectos de los fármacos , Chalconas/química , Chalconas/farmacología , Citocinas/metabolismo , Queratinocitos/efectos de los fármacos , Queratinocitos/metabolismo , Ovalbúmina/farmacología , Animales , Línea Celular , Evaluación Preclínica de Medicamentos , Humanos , Queratinocitos/inmunología , Masculino , Ratones , FN-kappa B/metabolismo , Linfopoyetina del Estroma TímicoRESUMEN
Thymic stromal lymphopoietin (TSLP), a master switch of allergic inflammation, plays an important role in the pathogenesis of allergic diseases. Although many compounds upregulate TSLP expression in vivo or in vitro, most of them are pollutants or toxicants. In the previous study, for the first time, we found that a steroid alkaloid derivative 02F04, which has a unique skeletal structure compared with other TSLP-inducing chemicals, significantly induced TSLP production in mouse keratinocytes. However, it is not investigated thoroughly that how 02F04 produces TSLP and why. In this study, we did a detailed investigation on the inducible effect and underlying molecular mechanism of 02F04 on TSLP production. We found that the peak time of TSLP mRNA level induced by 02F04 at 48â¯h led to a slow and continuous TSLP production in PAM212 cells. Besides, 02F04-induced TSLP production was significantly suppressed by inhibitors of Rho-associated protein kinase (ROCK), guanine nucleotide-binding protein subunit alpha q/11 (Gq/11) and extracellular signal-regulated kinase 1/2 (ERK1/2) at not only protein but also mRNA levels, and by siRNA-mediated knockdown of Gq or G11. This suggested that ROCK, Gq/11 and ERK1/2 signaling pathways were involved in 02F04-induced TSLP production. Increase in the level of p-ERK1/2 induced by 02F04 was suppressed by both inhibitors of ROCK and Gq/11, indicating that ROCK and Gq/11 molecules were located at the upstream of ERK1/2 to regulate 02F04-induced TSLP production. Gq/11 was located at the upstream of ROCK because the specific Gq/11 inhibitor of YM-254890 significantly reduced 02F04-induced actin stress fiber formation. Taken together, 02F04 upregulates a slow and continuous TSLP production through a novel Gq/11-ROCK-ERK1/2 signaling pathway. The thorough understanding the effect and mechanism of 02F04 on TSLP production is expected to supply it as a novel TSLP-regulating compound and a potential new tool for investigating the role of TSLP in allergic disorders.
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Alcaloides/farmacología , Citocinas/metabolismo , Queratinocitos/efectos de los fármacos , Queratinocitos/metabolismo , Alcaloides/química , Animales , Células Cultivadas , Citocinas/efectos de los fármacos , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Ratones , Proteína Quinasa 3 Activada por Mitógenos/metabolismo , Fosforilación/efectos de los fármacos , Activación Transcripcional/efectos de los fármacos , Regulación hacia Arriba/efectos de los fármacos , Linfopoyetina del Estroma TímicoRESUMEN
The structural diversity of natural products and their derivatives have long contributed to the development of new drugs. However, the difficulty in obtaining compounds bearing skeletally novel structures has recently led to a decline of pharmaceutical research into natural products. This paper reports the construction of a meroterpenoid-like library containing 25 compounds with diverse molecular scaffolds obtained from diversity-enhanced extracts. This method constitutes an approach for increasing the chemical diversity of natural-product-like compounds by combining natural product chemistry and diversity-oriented synthesis. Extensive pharmacological screening of the library revealed promising compounds for anti-osteoporotic and anti-lymphoma/leukemia drugs. This result indicates that the use of diversity-enhanced extracts is an effective methodology for producing chemical libraries for the purpose of drug discovery.
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BACKGROUND: Epimagnolin A is an ingredient of the Chinese crude drug Shin-i, derived from the dried flower buds of Magnolia fargesii and Magnolia flos, which has been traditionally used for the treatment of allergic rhinitis and nasal congestion, empyema, and sinusitis. The pharmacokinetic activity of epimagnolin A remains to be evaluated. PURPOSE: In this study, we examined the possible interactions of epimagnolin A with human ATP-binding cassette (ABC) transporter ABCB1, a membrane protein vital in regulating the pharmacokinetics of drugs and xenobiotics. STUDY DESIGN/METHODS: The interaction of epimagnolin A with ABCB1 was evaluated in calcein, ATPase, and MTT assays by using Flp-In-293/ABCB1 cells and purified ABCB1 and simulated in molecular docking studies. RESULTS: Epimagnolin A inhibited calcein export by Flp-In-293/ABCB1 cells in a concentration-dependent manner in a calcein assay. ATPase assay revealed a concentration-dependent stimulation of the ATPase activity of ABCB1 by epimagnolin A. Epimagnolin A also showed saturation kinetics in the relationship between the compound-stimulated ATPase activity and the compound concentration, suggesting Michaelis-Menten kinetics similar to those of the control drug, verapamil. Km and Vmax values were calculated from Hanes-Woolf plots of (compound concentration)â¯×â¯(compound-stimulated ATPase activity)-1â¯vs. (compound concentration); the Km of epimagnolin and verapamil was 42.9⯱â¯7.53 ⯵M and 12.3⯱â¯4.79⯠µM, respectively, and the corresponding Vmax values were 156⯱â¯15.0⯠µM and 109⯱â¯3.18⯠µM. Molecular docking studies on human ABCB1 showed that epimagnolin A docked to the same binding pocket as verapamil, and 3-(4,5-dimethyl-2-thiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assays showed that the sensitivities of Flp-In-293/ABCB1 cells against anti-cancer drugs were enhanced upon exposure to 10⯠µM epimagnolin A. CONCLUSION: These results strongly suggest that epimagnolin A affects the transport activity of ABCB1 as a substrate.
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Resistencia a Múltiples Medicamentos/efectos de los fármacos , Resistencia a Antineoplásicos/efectos de los fármacos , Lignanos/farmacología , Subfamilia B de Transportador de Casetes de Unión a ATP/metabolismo , Adenosina Trifosfatasas/metabolismo , Antineoplásicos Fitogénicos/farmacología , Línea Celular Tumoral , Humanos , Magnolia/química , Simulación del Acoplamiento Molecular , Verapamilo/farmacologíaRESUMEN
Thymic stromal lymphopoietin (TSLP) plays critical roles in inducing and exacerbating allergic diseases. Chemical compounds that induce TSLP production can enhance sensitization to antigens and exacerbate allergic inflammation. Hence, identifying such chemicals will be important to prevent an increase in allergic diseases. In the present study, we found, for the first time, that a steroid alkaloid derivative, code no. 02F04, concentration and time dependently induced mRNA expression and production of TSLP in a mouse keratinocyte cell line, PAM212. In particular, the activity of 02F04 was selective to TSLP. As an analogue of the liver X receptor (LXR) endogenous ligand, 02F04 rapidly increased ATP-binding cassette transporter A1 (ABCA1) expression by regulating the nuclear receptor of LXR. However, instead of being inhibited by the LXR antagonist, 02F04-induced TSLP production was delayed and markedly suppressed by inhibitors of phospholipase C (PLC), pan-protein kinase C (PKC), PKCδ, Rho-associated protein kinase (ROCK), extracellular signal-regulated kinase (ERK) 1/2, and IκΒ kinase 2 (IKK2). Treatment with 02F04 caused the formation of F-actin filaments surrounding the nucleus of PAM212 cells, which then disappeared following addition of ROCK inhibitor. 02F04 also induced phosphorylation of ERK1/2 from 2h after treatment, with a maximum at 24h, and increased nuclear factor-κB (NF-κB) promoter activity by 1.3-fold. Taken together, these results indicate that 02F04-induced TSLP production is regulated via distinct signal transduction pathways, including PLC, PKC, ROCK, ERK1/2, and NF-κB but not nuclear receptors. 02F04, with a unique skeletal structure in inducing TSLP production, can represent a potential new tool for investigating the role of TSLP in allergic diseases.
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Alcaloides/farmacología , Citocinas/metabolismo , Hipersensibilidad/metabolismo , Queratinocitos/fisiología , Esteroides/farmacología , Alcaloides/química , Animales , Línea Celular , Citocinas/genética , Regulación de la Expresión Génica , Queratinocitos/efectos de los fármacos , Receptores X del Hígado/química , Sistema de Señalización de MAP Quinasas , Ratones , Fosforilación , Proteína Quinasa C/metabolismo , Esteroides/química , Fosfolipasas de Tipo C/metabolismo , Linfopoyetina del Estroma TímicoRESUMEN
Nepodin, found in the roots of Rumex japonicus Houtt. (Polygonaceae), inhibits osteoclast differentiation and has an antidiabetic effect. We propose nepodin as an ingredient of new functional foods or as a drug candidate for reducing the risk of reduced locomotion resulting from diseases such as osteoporosis. Although there are no previous reports of R. obtusifolius L., which is found throughout Japan, having roots containing nepodin, we found nepodin in the roots of this species. Therefore, R. obtusifolius as well as R. japonicus was considered a candidate raw material for nepodin extraction. We also discuss the suitability of R. japonicus and R. obtusifolius as sources of raw nepodin for cultivation on the Ryukyu Islands. In this study, all specimens on the Ryukyu Islands were identified as R. japonicus. Conversely, all specimens on mainland Japan were R. obtusifolius. The DNA sequence of the chloroplast trnL-trnF intergenic spacer region and partial nuclear internal transcribed spacer was consistent with the identification of R. japonicus and R. obtusifolius by morphological characteristics of the perianth segments. Therefore, to avoid erroneous identification and misuse of the plant species used for extraction of raw materials, it is preferable to develop DNA markers for these two regions. The content of nepodin varied from undetectable to 0.34% of the fresh weight (%FW) in R. japonicus and from undetectable to 0.21%FW in R. obtusifolius. From a pharmacological perspective, as plants that might be suitable as raw materials for nepodin extraction, it became clear that both R. japonicus and R. obtusifolius can be used with the same expected extraction efficiency. Based on our findings, R. obtusifolius could not be confirmed as inhabiting the Ryukyu Islands. For this reason, to conserve the endemic genetic characteristics of the Ryukyu Islands and to prevent genetic pollution by R. obtusifolius, only R. japonicus should be cultivated on the Ryukyu Islands.
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Naftalenos/aislamiento & purificación , Extractos Vegetales/aislamiento & purificación , Rumex/química , ADN de Plantas/genética , Japón , Naftalenos/química , Naftalenos/metabolismo , Dispersión de las Plantas , Extractos Vegetales/química , Extractos Vegetales/metabolismo , Raíces de Plantas/química , Raíces de Plantas/genética , Raíces de Plantas/metabolismo , Polimorfismo Genético , Rumex/genética , Rumex/metabolismoRESUMEN
SCOPE: Bone homeostasis is ensured by the balance between bone formation and resorption. Thus, control of the recruitment, proliferation, and differentiation of bone cells is essential to maintain bone mass. The aim of this study was to elucidate the effects of rosmarinic acid as a potential therapeutic agent on bone metabolism using bone cells and a mouse model. METHODS AND RESULTS: Rosmarinic acid increased alkaline phosphatase activity and induced mineralization in osteoblasts. Addition of rosmarinic acid to cultures of calvarial osteoblastic cells prepared from T-cell factor/ß-catenin TOP-GAL mutant mice strongly induced the expression of LacZ and promoted stabilization of ß-catenin in the cytoplasm of ST2 cells, suggesting that rosmarinic acid affects the canonical Wnt signaling pathway. Moreover, rosmarinic acid inhibited not only osteoclast formation in cocultures of mouse bone marrow cells and osteoblasts, but also receptor activator of nuclear factor kappa-B ligand (RANKL)-induced osteoclastic differentiation in bone marrow-derived macrophages. RANKL-induced p38 mitogen-activated protein kinase and the expression of nuclear factor of activated T cell, c-Jun, and c-Fos were inhibited by rosmarinic acid in bone marrow macrophages. Finally, we confirmed that rosmarinic acid improved bone mass in a soluble RANKL-induced bone loss mouse model. CONCLUSION: Rosmarinic acid has dual regulatory effects on bone metabolism and may control the bone functions by controlling osteoblastic and osteoclastic differentiation.
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Resorción Ósea/tratamiento farmacológico , Cinamatos/farmacología , Depsidos/farmacología , Osteoblastos/efectos de los fármacos , Osteoclastos/efectos de los fármacos , Animales , Densidad Ósea/efectos de los fármacos , Células de la Médula Ósea/efectos de los fármacos , Resorción Ósea/inducido químicamente , Resorción Ósea/patología , Diferenciación Celular/efectos de los fármacos , Células Cultivadas , Técnicas de Cocultivo , Modelos Animales de Enfermedad , Masculino , Ratones Endogámicos C57BL , Ratones Endogámicos , Ratones Transgénicos , Osteoblastos/metabolismo , Osteoclastos/metabolismo , Ligando RANK/toxicidad , Proteína Wnt3A/genética , Proteína Wnt3A/metabolismo , beta Catenina/metabolismo , Ácido RosmarínicoRESUMEN
Nobiletin is a unique flavonoid having polymethoxy groups and has exhibited anti-inflammatory and antiobesity effects. Here, we examined the inhibition of nobiletin on melanogenesis induced by endothelin-1 (ET) and stem cell factor (SCF) in normal human melanocytes. Nobiletin dose dependently reduced ET plus SCF-stimulated tyrosinase activity without causing cytotoxicity. Nobiletin reduced cAMP-response element-binding protein (CREB) phosphorylation and microphthalmia-associated transcription factor (MITF) expression, which is a key transcription factor for tyrosinase expression in pigmentation induced by ET plus SCF stimulation. Nobiletin treatment effectively decreased ET plus SCF-induced Raf-1, MEK and ERK1/2 phosphorylation and also downregulated the forskolin-induced phosphorylation of CREB. Furthermore, nobiletin inhibited ET plus SCF-triggered production of melanin and expression of MITF/tyrosinase in a three-dimensional human epidermal model. In accordance with protein expression, the expression of genes related to the pigmentation was also increased in the cells stimulated with ET plus SCF and the cotreatment with nobiletin decreased obviously the ET plus SCF-triggered gene expressions of tyrosinase, PMEL, TRP1 and MITF. Nobiletin contributes to hypopigmentation by downregulating MITF and tyrosinase expression through reduced Raf-1 phosphorylation. Our findings implicate nobiletin as a potential new whitening agent.
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Endotelina-1/antagonistas & inhibidores , Flavonas/farmacología , Melaninas/antagonistas & inhibidores , Melanocitos/efectos de los fármacos , Preparaciones para Aclaramiento de la Piel/farmacología , Factor de Células Madre/antagonistas & inhibidores , Células Cultivadas , Colforsina/farmacología , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/genética , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/metabolismo , Endotelina-1/farmacología , Regulación de la Expresión Génica , Humanos , Quinasas Quinasa Quinasa PAM/genética , Quinasas Quinasa Quinasa PAM/metabolismo , Melaninas/biosíntesis , Melanocitos/citología , Melanocitos/metabolismo , Factor de Transcripción Asociado a Microftalmía/genética , Factor de Transcripción Asociado a Microftalmía/metabolismo , Proteína Quinasa 1 Activada por Mitógenos/genética , Proteína Quinasa 1 Activada por Mitógenos/metabolismo , Proteína Quinasa 3 Activada por Mitógenos/genética , Proteína Quinasa 3 Activada por Mitógenos/metabolismo , Monofenol Monooxigenasa/genética , Monofenol Monooxigenasa/metabolismo , Fosforilación/efectos de los fármacos , Proteínas Proto-Oncogénicas c-raf/genética , Proteínas Proto-Oncogénicas c-raf/metabolismo , Transducción de Señal , Factor de Células Madre/farmacología , Técnicas de Cultivo de Tejidos , Antígeno gp100 del Melanoma/genética , Antígeno gp100 del Melanoma/metabolismoRESUMEN
Many active components derived from edible natural resources such as plant extracts have recently attracted attention for their potential use as functional foods or drugs for preventing and treating metabolic diseases such as diabetes. To obtain a novel modulator of glucose metabolism, we conducted screening of a small compound library in cultured L6 myotubes. We identified nepodin that stimulated glucose uptake dose-dependently in differentiated L6 myotubes. The stimulatory effect of nepodin on glucose uptake was abrogated by a 5'-adenosine monophosphate-activated protein kinase (AMPK) inhibitor. In addition, nepodin stimulated the phosphorylation of AMPK. Nepodin also stimulated the translocation of GLUT4 to the plasma membrane in L6 myoblasts transfected with a Glut4 cDNA-coding vector and in differentiated L6 myotubes. In in vivo study, nepodin suppressed the increases in fasting blood glucose levels and improved the glucose intolerance of C57BL/KsJ-db/db mice, a type 2 diabetic animal model. Nepodin rescued the impaired phosphorylation of AMPK in the skeletal muscle of db/db mice. These results suggest that nepodin has an antidiabetic effect, which is at least partly mediated by stimulation of GLUT4 translocation via AMPK activation by nepodin.
Asunto(s)
Diabetes Mellitus Tipo 2/tratamiento farmacológico , Hipoglucemiantes/farmacología , Naftalenos/farmacología , Adenilato Quinasa/metabolismo , Animales , Glucemia , Línea Celular , Diabetes Mellitus Tipo 2/sangre , Evaluación Preclínica de Medicamentos , Expresión Génica/efectos de los fármacos , Glucosa/metabolismo , Intolerancia a la Glucosa , Transportador de Glucosa de Tipo 4/metabolismo , Hipoglucemiantes/uso terapéutico , Insulina/sangre , Resistencia a la Insulina , Metabolismo de los Lípidos/efectos de los fármacos , Hígado/efectos de los fármacos , Hígado/enzimología , Masculino , Ratones Endogámicos C57BL , Ratones Obesos , Naftalenos/uso terapéutico , Raíces de Plantas/química , Procesamiento Proteico-Postraduccional/efectos de los fármacos , Transporte de Proteínas , Ratas , Rumex/química , Transducción de Señal/efectos de los fármacosRESUMEN
Daidzein shows estrogenic, antioxidant and antiandrogenic properties as well as cell cycle regulatory activity. However, the antihyperglycemic effect of daidzein remains to be elucidated. In this study, we investigated the in vitro effect of daidzein on glucose uptake, AMPK phosphorylation and GLUT4 translocation on plasma membrane in L6 myotubes and its in vivo antihyperglycmic effect in obese-diabetic model db/db mice. Daidzein was found to promote glucose uptake, AMPK phosphorylation and GLUT4 translocation by Western blotting analyses in L6 myotubes under a condition of insulin absence. Promotion by daidzein of glucose uptake as well as GLUT4 translocation to plasma membrane by immunocytochemistry was also demonstrated in L6 myoblasts transfected with a GLUT4 cDNA-coding vector. Daidzein (0.1% in the diet) suppressed the rises in the fasting blood glucose, serum total cholesterol levels and homeostasis model assessment index of db/db mice. In addition, daidzein supplementation markedly improved the AMPK phosphorylation in gastrocnemius muscle of db/db mice. Daidzein also suppressed increases in blood glucose levels and urinary glucose excretion in KK-Ay mice, another Type 2 diabetic animal model. These in vitro and in vivo findings suggest that daidzein is preventive for Type 2 diabetes and an antidiabetic phytochemical.
Asunto(s)
Diabetes Mellitus Tipo 2/metabolismo , Transportador de Glucosa de Tipo 4/metabolismo , Glucosa/metabolismo , Isoflavonas/farmacología , Células Musculares/efectos de los fármacos , Adenilato Quinasa/metabolismo , Animales , Secuencia de Bases , Membrana Celular/efectos de los fármacos , Membrana Celular/metabolismo , Cartilla de ADN , Ratones , Células Musculares/metabolismo , Fosforilación , Transporte de ProteínasRESUMEN
SCOPE: Molecular mechanisms for the potential antihyperglycemic effect of equol remain to be elucidated. In this study, we investigated the in vitro effect of equol on glucose uptake, AMP-activated protein kinase (AMPK) phosphorylation, and glucose transporter 4 (GLUT4) translocation to plasma membrane in L6 myocytes, and its in vivo antihyperglycemic effect in obese-diabetic model ob/ob mice. METHODS AND RESULTS: Equol was found to promote glucose uptake, AMPK phosphorylation, and GLUT4 translocation detected by Western blotting analyses in L6 myotubes under a condition of insulin absence. Equol (0.05% in diet) suppressed the rise in serum glucose, cholesterol, triglyceride, and lipid peroxide concentrations and the hepatic triglyceride level as compared with those in the control group. Moreover, equol treatment suppressed the rises in fasting blood glucose level and improved the impaired glucose tolerance in ob/ob mice. Furthermore, equol treatment was demonstrated to improve expression of hepatic gluconeogenesis- and lipogenesis-related genes in terms of glucose and lipid metabolism. CONCLUSION: The hypoglycemic effect of equol is related to increased GLUT4 translocation to the plasma membrane via AMPK activation. In addition, equol suppresses the fasting blood glucose level and gene expression of hepatic enzymes related to glucose metabolism. These results strongly suggest that equol has antidiabetic potential.
Asunto(s)
Equol/farmacología , Hipoglucemiantes/farmacología , Células Musculares/efectos de los fármacos , Proteínas Quinasas Activadas por AMP/genética , Proteínas Quinasas Activadas por AMP/metabolismo , Adiponectina/sangre , Animales , Glucemia/metabolismo , Línea Celular , Quimiocina CCL2/sangre , Colesterol/sangre , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Intolerancia a la Glucosa/tratamiento farmacológico , Transportador de Glucosa de Tipo 4/genética , Transportador de Glucosa de Tipo 4/metabolismo , Insulina/sangre , Metabolismo de los Lípidos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Obesos , Células Musculares/metabolismo , Fibras Musculares Esqueléticas/efectos de los fármacos , Fibras Musculares Esqueléticas/metabolismo , Fosforilación , Ratas , Sustancias Reactivas al Ácido Tiobarbitúrico/metabolismo , Triglicéridos/sangre , Factor de Necrosis Tumoral alfa/sangreRESUMEN
Sodium dodecyl sulfate (SDS) and sodium dodecyl benzenesulfonate (SDBS) are widely used anionic surfactants in household, industrial, and institutional cleaners. Although there are many reports of their toxic effects, few studies have focused on the pharmacological properties of these surfactants. Peroxisome proliferator-activated receptor (PPAR) γ is a transcriptional factor belonging to the nuclear receptor superfamily. The ligands of PPARγ regulate its transcriptional activity and modulate many biological functions, including adipocyte differentiation and lipid metabolism. In this study, we investigated the ligand activities of SDS and SDBS for nuclear receptors using time-resolved fluorescence resonance energy transfer-based coactivator recruitment assays. SDS and SDBS showed selective ligand activities for PPARγ and these ligand activities were eliminated by a PPARγ antagonist. SDS and SDBS also promoted adipocyte differentiation accompanied by upregulation of adipocyte-specific gene expression in 3T3-L1 preadipocytes. These findings reveal novel actions of anionic alkyl surfactants as PPARγ ligands.
Asunto(s)
Bencenosulfonatos/farmacología , PPAR gamma/fisiología , Dodecil Sulfato de Sodio/farmacología , Tensoactivos/farmacología , Células 3T3/metabolismo , Adipocitos/citología , Adipocitos/metabolismo , Anilidas/farmacología , Animales , Diferenciación Celular/efectos de los fármacos , Regulación de la Expresión Génica , Ligandos , Metabolismo de los Lípidos/efectos de los fármacos , Ratones , PPAR gamma/agonistas , PPAR gamma/antagonistas & inhibidores , Regulación hacia ArribaRESUMEN
Nobiletin (NOB) is a polymethoxylated flavone present in citrus fruits and has been reported to have antitumor and anti-inflammatory effects. However, little is known about the effects of NOB on obesity and insulin resistance. In this study, we examined the effects of NOB on obesity and insulin resistance, and the underlying mechanisms, in high-fat diet (HFD)-induced obese mice. Obese mice were fed a HFD for 8 weeks and then treated without (HFD control group) or with NOB at 10 or 100mg/kg. NOB decreased body weight gain, white adipose tissue (WAT) weight and plasma triglyceride. Plasma glucose levels tended to decrease compared with the HFD group and improved plasma adiponectin levels and glucose tolerance. Furthermore, NOB altered the expression levels of several lipid metabolism-related and adipokine genes. NOB increased the mRNA expression of peroxisome proliferator-activated receptor (PPAR)-γ, sterol regulatory element-binding protein-1c, fatty acid synthase, stearoyl-CoA desaturase-1, PPAR-α, carnitine palmitoyltransferase-1, uncoupling protein-2 and adiponectin, and decreased the mRNA expression of tumor necrosis factor-α and monocyte chemoattractant protein-1 in WAT. NOB also up-regulated glucose transporter-4 protein expression and Akt phosphorylation and suppressed IκBα degradation in WAT. Taken together, these results suggest that NOB improves adiposity, dyslipidemia, hyperglycemia and insulin resistance. These effects may be elicited by regulating the expression of lipid metabolism-related and adipokine genes, and by regulating the expression of inflammatory makers and activity of the insulin signaling pathway.