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1.
J Neurochem ; 151(3): 370-385, 2019 11.
Artículo en Inglés | MEDLINE | ID: mdl-31063584

RESUMEN

Neuronal expression of beta-secretase 1 (BACE1) has been implicated in the progression of Alzheimer's disease. However, the mechanisms that regulate BACE1 expression are unclear. Here, we show that peroxisome proliferator-activated receptor delta (PPARδ) decreases BACE1 expression by up-regulating suppressor of cytokine signaling 1 (SOCS1) in SH-SY5Y neuroblastoma cells. The activation of PPARδ by GW501516, a specific PPARδ agonist, inhibited expression of BACE1. This effect was abrogated by shRNA-mediated knockdown of PPARδ and by treatment with the PPARδ antagonist GSK0660, indicating that PPARδ is involved in GW501516-mediated suppression of BACE1 expression. On the other hand, GW501516-activated PPARδ induced expression of SOCS1, which is a negative regulator of cytokine signal transduction, at the transcriptional level by binding to a PPAR response element in its promoter. This GW501516-mediated induction of SOCS1 expression led to down-regulation of BACE1 expression via inactivation of signal transducer and activator of transcription 1. GW501516-activated PPARδ suppressed the generation of neurotoxic amyloid beta (Aß) in accordance with the decrease in BACE1 expression. Taken together, these results indicate that PPARδ attenuates BACE1 expression via SOCS1-mediated inhibition of signal transducer and activator of transcription 1 signaling, thereby suppressing BACE1-associated generation of neurotoxic Aß.


Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/efectos de los fármacos , Péptidos beta-Amiloides/metabolismo , Ácido Aspártico Endopeptidasas/efectos de los fármacos , Proteína 1 Supresora de la Señalización de Citocinas/efectos de los fármacos , Tiazoles/farmacología , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Ácido Aspártico Endopeptidasas/metabolismo , Humanos , Janus Quinasa 2/efectos de los fármacos , Janus Quinasa 2/metabolismo , Factor de Transcripción STAT1/metabolismo , Proteína 1 Supresora de la Señalización de Citocinas/metabolismo , Regulación hacia Arriba
2.
FASEB J ; 33(6): 7707-7720, 2019 06.
Artículo en Inglés | MEDLINE | ID: mdl-30897345

RESUMEN

Peroxisome proliferator-activated receptor (PPAR)-γ has been implicated as a key player in the regulation of adiponectin levels via both transcriptional and posttranscriptional mechanisms. Herein, we show that PPAR-γ interacts with human antigen R (HuR) and that the PPAR-γ-HuR complex dissociates following activation of PPAR-γ by rosiglitazone, a specific ligand of PPAR-γ. This rosiglitazone-dependent dissociation of HuR from PPAR-γ leads to nucleocytoplasmic shuttling of HuR and its binding to the 3'-UTR of adiponectin mRNA. PPAR-γ with H321A and H447A double mutation (PPAR-γH321/447A), a mutant lacking ligand-binding activity, impaired HuR dissociation from the PPAR-γ-HuR complex, resulting in reduced nucleocytoplasmic shuttling, even in the presence of rosiglitazone. Consequently, rosiglitazone up-regulated adiponectin levels by modulating the stability of adiponectin mRNA, whereas these effects were abolished by HuR ablation or blocked in cells expressing the PPAR-γH321/447A mutant, indicating that the interaction of PPAR-γ and HuR is a critical event during adiponectin expression. Taken together, the findings demonstrate a novel mechanism for regulating adiponectin expression at the posttranscriptional level and suggest that ligand-mediated activation of PPAR-γ to interfere with interaction of HuR could offer a therapeutic strategy for inflammation-associated diseases that involve decreased adiponectin mRNA stability.-Hwang, J. S., Lee, W. J., Hur, J., Lee, H. G., Kim, E., Lee, G. H., Choi, M.-J., Lim, D.-S., Paek, K. S., Seo, H. G. Rosiglitazone-dependent dissociation of HuR from PPAR-γ regulates adiponectin expression at the posttranscriptional level.


Asunto(s)
Adiponectina/metabolismo , Proteína 1 Similar a ELAV/metabolismo , PPAR gamma/metabolismo , Procesamiento Postranscripcional del ARN/efectos de los fármacos , Rosiglitazona/farmacología , Adiponectina/genética , Animales , Línea Celular , Humanos , Ligandos , Unión Proteica , Transcripción Genética
3.
PLoS One ; 14(1): e0210482, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30620754

RESUMEN

We investigated the effect of peroxisome proliferator-activated receptor δ (PPARδ) on angiotensin II (Ang II)-triggered hypertrophy of vascular smooth muscle cells (VSMCs). Activation of PPARδ by GW501516, a specific ligand of PPARδ, significantly inhibited Ang II-stimulated protein synthesis in a concentration-dependent manner, as determined by [3H]-leucine incorporation. GW501516-activated PPARδ also suppressed Ang II-induced generation of reactive oxygen species (ROS) in VSMCs. Transfection of small interfering RNA (siRNA) against PPARδ significantly reversed the effects of GW501516 on [3H]-leucine incorporation and ROS generation, indicating that PPARδ is involved in these effects. By contrast, these GW501516-mediated actions were potentiated in VSMCs transfected with siRNA against NADPH oxidase (NOX) 1 or 4, suggesting that ligand-activated PPARδ elicits these effects by modulating NOX-mediated ROS generation. The phosphatidylinositol 3-kinase inhibitor LY294002 also inhibited Ang II-stimulated [3H]-leucine incorporation and ROS generation by preventing membrane translocation of Rac1. These observations suggest that PPARδ is an endogenous modulator of Ang II-triggered hypertrophy of VSMCs, and is thus a potential target to treat vascular diseases associated with hypertrophic changes of VSMCs.


Asunto(s)
Angiotensina II/farmacología , Músculo Liso Vascular/efectos de los fármacos , Miocitos del Músculo Liso/efectos de los fármacos , PPAR delta/metabolismo , Especies Reactivas de Oxígeno/antagonistas & inhibidores , Animales , Aumento de la Célula/efectos de los fármacos , Células Cultivadas , Hipertrofia , Ligandos , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/patología , Miocitos del Músculo Liso/metabolismo , NADPH Oxidasa 1/genética , NADPH Oxidasa 1/metabolismo , PPAR delta/agonistas , Transporte de Proteínas/efectos de los fármacos , Interferencia de ARN , Ratas , Especies Reactivas de Oxígeno/metabolismo , Tiazoles/metabolismo , Tiazoles/farmacología , Proteína de Unión al GTP rac1/metabolismo
4.
Int J Cancer ; 143(11): 2985-2996, 2018 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-30204243

RESUMEN

Peroxisome proliferator-activated receptor (PPAR) δ is a promising therapeutic target in metabolic and inflammatory disorders. However, its role in oncogenesis is controversial, and its therapeutic potential remains to be determined. In our study, we show that ligand-activated PPARδ forms a complex with the proto-oncogene product c-Myc. The interaction of PPARδ with c-Myc affected the transcriptional activity of c-Myc and the expression of its target genes. The PPARδ-dependent regulation of c-Myc activity was associated with decreased tumorigenicity in breast cancer cells. Administration of the PPARδ ligand GW501516 inhibited tumor growth in xenograft model mice bearing MDA-MB-231 cells stably expressing wild-type PPARδ, but not those expressing dominant-negative PPARδ, by interfering with c-Myc function through protein-protein interaction. Our results indicating that PPARδ forms an antitumorigenic complex with c-Myc in the presence of ligand suggest a potential role of PPARδ in breast cancer development.


Asunto(s)
Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/metabolismo , Carcinogénesis/efectos de los fármacos , Carcinogénesis/metabolismo , PPAR delta/metabolismo , Proteínas Proto-Oncogénicas c-myc/metabolismo , Tiazoles/farmacología , Células A549 , Animales , Línea Celular , Línea Celular Tumoral , Transformación Celular Neoplásica/efectos de los fármacos , Transformación Celular Neoplásica/metabolismo , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Células HEK293 , Células HeLa , Humanos , Ligandos , Células MCF-7 , Células PC12 , Proto-Oncogenes Mas , ARN Interferente Pequeño/metabolismo , Ratas
5.
J Cell Biochem ; 119(7): 5609-5619, 2018 07.
Artículo en Inglés | MEDLINE | ID: mdl-29388693

RESUMEN

Neuroinflammation-associated release of glutamate from activated microglia has been implicated in the progression of neurodegenerative diseases. However, the regulatory mechanisms underlying this glutamate release are poorly understood. Here, we show that peroxisome proliferator-activated receptor delta (PPARδ) modulates neurotoxicity by inhibiting glutamate release in lipopolysaccharide (LPS)-activated BV-2 microglial cells. Activation of PPARδ by GW501516, a specific PPARδ agonist, inhibited glutamate release in BV-2 cells. This effect of GW501516 was significantly blocked by shRNA-mediated knockdown of PPARδ and by treatment with GSK0660, a specific PPARδ antagonist, indicating that PPARδ is associated with blockade of glutamate release. Additionally, GW501516-activated PPARδ suppressed generation of reactive oxygen species and expression of gp91phox, a functional subunit of NADPH oxidase 2, in BV-2 cells stimulated with LPS. The inhibitory effect of GW501516 on gp91phox expression and glutamate release was further potentiated in the presence of AG490, a specific inhibitor of janus kinase 2 (JAK2), leading to the inhibition of signal transducer and activator of transcription 1 (STAT1). By contrast, GW501516 upregulated the expression of suppressor of cytokine signaling 1 (SOCS1), an endogenous inhibitor of JAK2. Furthermore, neurotoxicity induced by conditioned media from LPS-stimulated BV-2 cells was significantly reduced when conditioned media from BV-2 cells treated with both LPS and GW501516 were used. These results indicate that PPARδ attenuates LPS-triggered neuroinflammation by enhancing SOCS1-mediated inhibition of JAK2/STAT1 signaling, thereby inhibiting neurotoxicity associated with glutamate release.


Asunto(s)
Ácido Glutámico/metabolismo , Lipopolisacáridos/toxicidad , Microglía/efectos de los fármacos , Neuroblastoma/tratamiento farmacológico , Síndromes de Neurotoxicidad/tratamiento farmacológico , PPAR delta/agonistas , Tiazoles/farmacología , Animales , Células Cultivadas , Janus Quinasa 2/metabolismo , Ratones , Microglía/metabolismo , Microglía/patología , Neuroblastoma/metabolismo , Neuroblastoma/patología , Síndromes de Neurotoxicidad/metabolismo , Síndromes de Neurotoxicidad/patología , PPAR delta/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Factor de Transcripción STAT1/metabolismo , Transducción de Señal
6.
J Vasc Res ; 55(2): 75-86, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29408825

RESUMEN

Thrombospondin-1 (TSP-1) is implicated in vascular diseases associated with oxidative stress, such as abdominal aortic aneurysms, ischemia-reperfusion injury, and atherosclerosis. However, the regulatory mechanisms underlying TSP-1 expression are not fully elucidated. In this study, we found that peroxisome proliferator-activated receptor δ (PPARδ) inhibited oxidative stress-induced TSP-1 expression and migration in vascular smooth muscle cells (VSMCs). Activation of PPARδ by GW501516, a specific ligand for PPARδ, significantly attenuated hydrogen peroxide (H2O2)-induced expression of TSP-1 in VSMCs. Small interfering RNA-mediated knockdown of PPARδ and treatment with GSK0660, a selective PPARδ antagonist, reversed the effect of GW501516 on H2O2-induced expression of TSP-1, suggesting that PPARδ is associated with GW501516 activity. Furthermore, JNK (c-Jun N-terminal kinase), but not p38 and ERK (extracellular signal-regulated kinase), mediated PPARδ-dependent inhibition of TSP-1 expression in VSMCs exposed to H2O2. GW501516- activated PPARδ also reduced the H2O2-induced generation of reactive oxygen species, concomitant with inhibition of VSMC migration. In particular, TSP-1 contributed to the action of PPARδ in the regulation of H2O2-induced interleukin-1ß expression. These results suggest that PPARδ-modulated downregulation of TSP-1 is associated with reduced cellular oxidative stress, thereby inhibiting H2O2-induced pheno-typic changes in vascular cells.


Asunto(s)
Antioxidantes/farmacología , Músculo Liso Vascular/efectos de los fármacos , Miocitos del Músculo Liso/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , PPAR delta/agonistas , Tiazoles/farmacología , Trombospondina 1/metabolismo , Animales , Aorta Torácica/efectos de los fármacos , Aorta Torácica/metabolismo , Movimiento Celular/efectos de los fármacos , Células Cultivadas , Relación Dosis-Respuesta a Droga , Peróxido de Hidrógeno/farmacología , Interleucina-1beta/metabolismo , Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , Masculino , Músculo Liso Vascular/metabolismo , Miocitos del Músculo Liso/metabolismo , PPAR delta/genética , PPAR delta/metabolismo , Interferencia de ARN , Ratas Sprague-Dawley , Transducción de Señal/efectos de los fármacos , Factores de Tiempo , Transfección
7.
PeerJ ; 6: e4208, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29312829

RESUMEN

BACKGROUND: The release of high mobility group box 1 (HMGB1) induced by inflammatory signals acts as a cellular alarmin to trigger a chain of inflammatory responses. Although the inflammatory actions of HMGB1 are well studied, less is known about the therapeutic agents that can impede its release. This study investigated whether the isoflavonoid formononetin can modulate HMGB1 release in cellular inflammatory responses. METHODS: RAW264.7 murine macrophages were exposed to lipopolysaccharide (LPS) in the presence or absence of formononetin. The levels of HMGB1 release, sirtuin 1 (SIRT1) expression, and HMGB1 acetylation were analyzed by immunoblotting and real-time polymerase chain reaction. The effects of resveratrol and sirtinol, an activator and inhibitor of SIRT1, respectively, on LPS-induced HMGB1 release were also evaluated. RESULTS: Formononetin modulated cellular inflammatory responses by suppressing the release of HMGB1 by macrophages exposed to LPS. In RAW264.7 cells, formononetin significantly attenuated LPS-induced release of HMGB1 into the extracellular environment, which was accompanied by a reduction in its translocation from the nucleus to the cytoplasm. In addition, formononetin significantly induced mRNA and protein expression of SIRT1 in a peroxisome proliferator-activated receptor δ (PPARδ)-dependent manner. These effects of formononetin were dramatically attenuated in cells treated with small interfering RNA (siRNA) against PPARδ or with GSK0660, a specific inhibitor of PPARδ, indicating that PPARδ is involved in formononetin-mediated SIRT1 expression. In line with these effects, formononetin-mediated inhibition of HMGB1 release in LPS-treated cells was reversed by treatment with SIRT1-targeting siRNA or sirtinol, a SIRT1 inhibitor. By contrast, resveratrol, a SIRT1 activator, further potentiated the inhibitory effect of formononetin on LPS-induced HMGB1 release, revealing a possible mechanism by which formononetin regulates HMGB1 release through SIRT1. Furthermore, modulation of SIRT1 expression by transfection of SIRT1- or PPARδ-targeting siRNA significantly counteracted the inhibitory effects of formononetin on LPS-induced HMGB1 acetylation, which was responsible for HMGB1 release. DISCUSSION: This study shows for the first time that formononetin inhibits HMGB1 release by decreasing HMGB1 acetylation via upregulating SIRT1 in a PPARδ-dependent manner. Formononetin consequently exhibits anti-inflammatory activity. Identification of agents, such as formononetin, which can block HMGB1 release, may help to treat inflammation-related disorders.

8.
Diabetes ; 67(3): 360-371, 2018 03.
Artículo en Inglés | MEDLINE | ID: mdl-29233935

RESUMEN

Peroxisome proliferator-activated receptor (PPAR) δ plays a pivotal role in metabolic homeostasis through its effect on insulin signaling. Although diverse genomic actions of PPARδ are postulated, the specific molecular mechanisms whereby PPARδ controls insulin signaling have not been fully elucidated. We demonstrate here that short-term activation of PPARδ results in the formation of a stable complex with nuclear T-cell protein tyrosine phosphatase 45 (TCPTP45) isoform. This interaction of PPARδ with TCPTP45 blocked translocation of TCPTP45 into the cytoplasm, thereby preventing its interaction with the insulin receptor, which inhibits insulin signaling. Interaction of PPARδ with TCPTP45 blunted interleukin 6-induced insulin resistance, leading to retention of TCPTP45 in the nucleus, thereby facilitating deactivation of the signal transducer and activator of transcription 3 (STAT3)-suppressor of cytokine signaling 3 (SOCS3) signal. Finally, GW501516-activated PPARδ improved insulin signaling and glucose intolerance in mice fed a high-fat diet through its interaction with TCPTP45. This novel interaction of PPARδ constitutes the most upstream component identified of the mechanism downregulating insulin signaling.


Asunto(s)
Intolerancia a la Glucosa/prevención & control , Hepatocitos/efectos de los fármacos , Resistencia a la Insulina , Obesidad/tratamiento farmacológico , PPAR delta/agonistas , Proteína Tirosina Fosfatasa no Receptora Tipo 2/metabolismo , Tiazoles/farmacología , Transporte Activo de Núcleo Celular/efectos de los fármacos , Adipocitos Blancos/efectos de los fármacos , Adipocitos Blancos/inmunología , Adipocitos Blancos/metabolismo , Adipocitos Blancos/patología , Empalme Alternativo , Animales , Antiinflamatorios no Esteroideos/farmacología , Antiinflamatorios no Esteroideos/uso terapéutico , Línea Celular , Células Cultivadas , Intolerancia a la Glucosa/etiología , Intolerancia a la Glucosa/inmunología , Hepatocitos/inmunología , Hepatocitos/metabolismo , Hepatocitos/patología , Humanos , Masculino , Ratones Endogámicos ICR , Fibras Musculares Esqueléticas/efectos de los fármacos , Fibras Musculares Esqueléticas/inmunología , Fibras Musculares Esqueléticas/metabolismo , Fibras Musculares Esqueléticas/patología , Obesidad/metabolismo , Obesidad/patología , Obesidad/fisiopatología , PPAR delta/antagonistas & inhibidores , PPAR delta/genética , PPAR delta/metabolismo , Multimerización de Proteína/efectos de los fármacos , Proteína Tirosina Fosfatasa no Receptora Tipo 2/química , Proteína Tirosina Fosfatasa no Receptora Tipo 2/genética , Interferencia de ARN , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/metabolismo , Organismos Libres de Patógenos Específicos , Tiazoles/uso terapéutico
9.
Oncotarget ; 8(55): 94091-94103, 2017 Nov 07.
Artículo en Inglés | MEDLINE | ID: mdl-29212212

RESUMEN

Migration and invasion of cancer cells into surrounding tissue is a key stage of cancer metastasis. Here, we show that peroxisome proliferator-activated receptor (PPAR) δ regulates migration and invasion of human breast cancer cells via thrombospondin-1 (TSP-1) and its degrading protease, a disintegrin and metalloprotease domains with thrombospondin motifs 1 (ADAMTS1). Activation of PPARδ by GW501516, a specific ligand for PPARδ, led to marked inhibition in the cell migration and TSP-1 expression of breast cancer. These effects were suppressed by small interfering RNA-mediated knock-down of ADAMTS1, indicating that ADAMTS1 is involved in PPARδ-mediated inhibition of migration and TSP-1 expression in breast cancer cells. In addition, ligand-activated PPARδ upregulated expression of ADAMTS1 at the transcriptional level via binding of PPARδ to a direct repeat-1 site within the ADAMTS1 gene promoter. Furthermore, ligand-activated PPARδ suppressed invasion of breast cancer cells in an ADAMTS1-dependent manner. Taken together, these results demonstrate that PPARδ suppresses migration and invasion of breast cancer cells by downregulating TSP-1 in a process mediated by upregulation of ADAMTS1.

10.
BMC Complement Altern Med ; 17(1): 212, 2017 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-28403838

RESUMEN

BACKGROUND: Dalbergia odorifera T. Chen (Leguminosae) is an indigenous medicinal herb that is widely used as a popular remedy in northern and eastern Asia. However, the cellular mechanisms underlying the biological activity of D. odorifera are not fully elucidated. METHODS: Anti-inflammatory effect of D. odorifera extract (DOE) was determined through intraperitoneal injection in a mouse model of endotoxemia induced by lipopolysaccharide (LPS). RAW 264.7 cells, a murine macrophage, were also treated with LPS to generate a cellular model of inflammation, and investigated the anti-inflammatory activity and underlying mechanisms of DOE and its constituent isoliquiritigenin. RESULTS: DOE dose-dependently inhibited LPS-induced release of high mobility group box 1 (HMGB1), a late proinflammatory cytokine, and decreased cytosolic translocation of HMGB1 in RAW264.7 cells. This inhibitory effect of DOE on HMGB1 release was observed in cells treated with DOE before or after LPS treatment, suggesting that DOE is effective for both treatment and prevention. In addition, DOE significantly inhibited LPS-induced formation of nitric oxide (NO) and expression of inducible NO synthase (iNOS) in a dose-dependent manner. These effects of DOE were accompanied by suppression of HMGB1 release triggered by LPS, suggesting a possible mechanism by which DOE modulates HMGB1 release through NO signaling. Isoriquiritigenin, a constituent of DOE, also attenuated LPS-triggered NO formation and HMGB1 release in RAW264.7 cells, indicating that isoriquiritigenin is an indexing molecule for the anti-inflammatory properties of DOE. Furthermore, c-Jun N-terminal kinase, but not extracellular signal-regulated kinase and p38, mediated DOE-dependent inhibition of HMGB1 release and NO/iNOS induction in RAW 264.7 cells exposed to LPS. Notably, administration of DOE ameliorated survival rates in a mouse model of endotoxemia induced by LPS, where decreased level of circulating HMGB1 was observed. CONCLUSION: These results suggest that DOE confers resistance to LPS-triggered inflammation through NO-mediated inhibitory effects on HMGB1 release.


Asunto(s)
Antiinflamatorios no Esteroideos/uso terapéutico , Dalbergia/química , Endotoxemia/tratamiento farmacológico , Proteína HMGB1/antagonistas & inhibidores , Fitoterapia , Extractos Vegetales/uso terapéutico , Animales , Antiinflamatorios no Esteroideos/aislamiento & purificación , Modelos Animales de Enfermedad , Endotoxemia/inducido químicamente , Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , Lipopolisacáridos , Macrófagos/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos BALB C , Óxido Nítrico/metabolismo , Células RAW 264.7 , Transducción de Señal/efectos de los fármacos
11.
Pharmacol Res ; 114: 47-55, 2016 12.
Artículo en Inglés | MEDLINE | ID: mdl-27771463

RESUMEN

Silent mating type information regulation 2 homolog 1 (SIRT1), a NAD-dependent deacetylase, mediates cellular processes involved in gene silencing and aging. The regulation of lifespan by SIRT1 has been extensively investigated, but less is known about the mechanisms associated with its cellular turnover during inflammatory responses. In this study, we found that peroxisome proliferator-activated receptor (PPAR) γ is associated with SIRT1 stability in murine macrophage RAW 264.7 cells exposed to lipopolysaccharide (LPS). Activation of PPARγ by rosiglitazone, a specific ligand of PPARγ, rescues LPS-induced destabilization of SIRT1, with a concomitant decrease in phosphorylation of residue Ser-46, which is targeted by JNK-1 to promote proteasome-mediated degradation of SIRT1. The rosiglitazone-mediated increase in SIRT1 stability is accompanied by upregulation of mitogen-activated protein kinase phosphatase (MKP)-7, a JNK-specific phosphatase. These effects are significantly influenced by ablation or ectopic expression of PPARγ, indicating that PPARγ is directly involved in the regulation of SIRT1 stability. Furthermore, gain of MKP-7 function mimicked the effect of rosiglitazone on LPS-induced destabilization and ubiquitination of SIRT1. These results indicate that PPARγ-dependent upregulation of MKP-7 improves the stability of SIRT1 by inactivating JNK during inflammatory responses of LPS-activated macrophages.


Asunto(s)
Fosfatasas de Especificidad Dual/inmunología , Hipoglucemiantes/farmacología , Lipopolisacáridos/inmunología , Macrófagos/efectos de los fármacos , Proteína Quinasa 8 Activada por Mitógenos/antagonistas & inhibidores , Fosfatasas de la Proteína Quinasa Activada por Mitógenos/inmunología , Sirtuina 1/inmunología , Tiazolidinedionas/farmacología , Animales , Células CHO , Cricetulus , Humanos , Macrófagos/inmunología , Macrófagos/metabolismo , Ratones , Proteína Quinasa 8 Activada por Mitógenos/inmunología , PPAR gamma/inmunología , Proteolisis/efectos de los fármacos , Células RAW 264.7 , Rosiglitazona , Sirtuina 1/metabolismo , Regulación hacia Arriba/efectos de los fármacos
12.
Mol Pharmacol ; 90(5): 522-529, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27573670

RESUMEN

Peroxisome proliferator-activated receptor δ (PPARδ) has been implicated in vascular pathophysiology. However, its functions in atherogenic changes of the vascular wall have not been fully elucidated. PPARδ activated by GW501516 (2-[2-methyl-4-[[4-methyl-2-[4-(trifluoromethyl)phenyl]-1,3-thiazol-5-yl]methylsulfanyl]phenoxy]acetic acid) significantly inhibited the migration and proliferation of vascular smooth muscle cells (VSMCs) triggered by oxidized low-density lipoprotein (oxLDL). These GW501516-mediated effects were significantly reversed by PPARδ-targeting small-interfering RNA (siRNA), indicating that PPARδ is involved in the action of GW501516. The antiproliferative effect of GW501516 was directly linked to cell cycle arrest at the G0/G1 to S phase transition, which was followed by the down-regulation of cyclin-dependent kinase 4 along with increased levels of p21 and p53. In VSMCs treated with GW501516, the expression of sirtuin 1 (SIRT1) mRNA and protein was time-dependently increased. This GW501516-mediated up-regulation of SIRT1 expression was also demonstrated even in the presence of oxLDL. In addition, GW501516-dependent inhibition of oxLDL-triggered migration and proliferation of VSMCs was almost completely abolished in the presence of SIRT1-targeting siRNA. These effects of GW501516 on oxLDL-triggered phenotypic changes of VSMCs were also demonstrated via activation or inhibition of SIRT1 activity by resveratrol or sirtinol, respectively. Finally, gain or loss of SIRT1 function imitated the action of PPARδ on oxLDL-triggered migration and proliferation of VSMCs. Taken together, these observations indicate that PPARδ-dependent up-regulation of SIRT1 contributes to the antiatherogenic activities of PPARδ by suppressing the migration and proliferation of VSMCs linked to vascular diseases such as restenosis and atherosclerosis.


Asunto(s)
Movimiento Celular/efectos de los fármacos , Lipoproteínas LDL/farmacología , Músculo Liso Vascular/citología , Miocitos del Músculo Liso/citología , Miocitos del Músculo Liso/metabolismo , PPAR delta/metabolismo , Sirtuina 1/metabolismo , Adenoviridae/metabolismo , Animales , Ciclo Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Regulación hacia Abajo/efectos de los fármacos , Técnicas de Silenciamiento del Gen , Miocitos del Músculo Liso/efectos de los fármacos , Interferencia de ARN/efectos de los fármacos , Ratas , Tiazoles
13.
Sci Rep ; 5: 15971, 2015 Nov 02.
Artículo en Inglés | MEDLINE | ID: mdl-26522327

RESUMEN

Inflammatory signal-mediated release of high-mobility group box 1 (HMGB1) is a damage-associated molecular pattern or alarmin. The inflammatory functions of HMGB1 have been extensively investigated; however, less is known about the mechanisms controlling HMGB1 release. We show that SIRT1, the human homolog of the Saccharomyces cerevisiae protein silent information regulator 2, which is involved in cellular senescence and possibly the response to inflammation, forms a stable complex with HMGB1 in murine macrophage RAW264.7 cells. SIRT1 directly interacted with HMGB1 via its N-terminal lysine residues (28-30), and thereby inhibited HMGB1 release to improve survival in an experimental model of sepsis. By contrast, inflammatory stimuli such as lipopolysaccharide (LPS) and tumor necrosis factor-α promoted HMGB1 release by provoking its dissociation from SIRT1 dependent on acetylation, thereby increasing the association between HMGB1 and chromosome region maintenance 1, leading to HMGB1 translocation. In vivo infection with wild-type SIRT1 and HMGB1(K282930R), a hypo-acetylation mutant, improved survival (85.7%) during endotoxemia more than infection with wild-type SIRT1 and HMGB1-expressing adenovirus, indicating that the acetylation-dependent interaction between HMGB1 and SIRT1 is critical for LPS-induced lethality. Taken together, we propose that SIRT1 forms an anti-inflammatory complex with HMGB1, allowing cells to bypass the response to inflammation.


Asunto(s)
Endotoxemia/metabolismo , Proteína HMGB1/metabolismo , Sirtuina 1/metabolismo , Acetilación , Animales , Línea Celular , Línea Celular Tumoral , Modelos Animales de Enfermedad , Células HEK293 , Células HL-60 , Humanos , Inflamación/inducido químicamente , Inflamación/metabolismo , Lipopolisacáridos/farmacología , Macrófagos/metabolismo , Ratones , Sepsis/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Células U937
14.
J Dermatol Sci ; 80(3): 186-95, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26481780

RESUMEN

BACKGROUND: The phenotypic changes that accompany differentiation of resident fibroblasts into myofibroblasts are important aspects of the wound healing process. Recent studies showed that peroxisome proliferator-activated receptor (PPAR) δ plays a critical role in wound healing. OBJECTIVE: To determine whether the nuclear receptor PPARδ can modulate the differentiation of human dermal fibroblasts (HDFs) into myofibroblasts. METHODS: These studies were undertaken in primary HDFs using Western blot analyses, small interfering (si)RNA-mediated gene silencing, reporter gene assays, chromatin immunoprecipitation (ChIP), migration assays, collagen gel contraction assays, and real-time PCR. RESULTS: Activation of PPARδ by GW501516, a specific ligand of PPARδ, specifically upregulated the myofibroblast marker α-smooth muscle actin (α-SMA) in a time- and concentration-dependent manner. This induction was significantly inhibited by the presence of siRNA against PPARδ, indicating that PPARδ is involved in myofibroblast transdifferentiation of HDFs. Ligand-activated PPARδ increased α-SMA promoter activity in a dual mode by directly binding a direct repeat-1 (DR1) site in the α-SMA promoter, and by inducing expression of transforming growth factor (TGF)-ß, whose downstream effector Smad3 interacts with a Smad-binding element (SBE) in another region of the promoter. Mutations in these cis-elements totally abrogated transcriptional activation of the α-SMA gene by the PPARδ ligand; thus both sites represent novel types of PPARδ response elements. GW501516-activated PPARδ also increased the migration and contractile properties of HDFs, as demonstrated by Transwell and collagen lattice contraction assays, respectively. In addition, PPARδ-mediated upregulation of α-SMA was correlated with elevated expression of myofibroblast markers such as collagen I and fibronectin, with a concomitant reduction in expression of the epithelial marker E-cadherin. CONCLUSION: PPARδ plays pivotal roles in wound healing by promoting fibroblast-to-myofibroblast differentiation via TGF-ß/Smad3 signaling.


Asunto(s)
Actinas/metabolismo , Diferenciación Celular , PPAR delta/efectos de los fármacos , PPAR delta/metabolismo , Tiazoles/farmacología , Cicatrización de Heridas , Actinas/genética , Cadherinas/metabolismo , Movimiento Celular , Células Cultivadas , Colágeno Tipo I/metabolismo , Fibroblastos , Fibronectinas/metabolismo , Humanos , Ligandos , PPAR delta/genética , Regiones Promotoras Genéticas , ARN Interferente Pequeño/farmacología , Elementos de Respuesta , Transducción de Señal , Piel/citología , Proteína smad3/metabolismo , Activación Transcripcional , Factor de Crecimiento Transformador beta/genética , Factor de Crecimiento Transformador beta/metabolismo , Regulación hacia Arriba/efectos de los fármacos
15.
Int J Biochem Cell Biol ; 62: 54-61, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25732738

RESUMEN

The peroxisome proliferator-activated receptor delta (PPARδ) has been implicated in the modulation of vascular homeostasis. However, its roles in the apoptotic cell death of vascular smooth muscle cells (VSMCs) are poorly understood. Here, we demonstrate that PPARδ modulates oxidized low-density lipoprotein (oxLDL)-induced apoptosis of VSMCs through the transforming growth factor-ß (TGF-ß) and focal adhesion kinase (FAK) signaling pathways. Activation of PPARδ by GW501516, which is a specific ligand, significantly inhibited oxLDL-induced cell death and generation of reactive oxygen species in VSMCs. These inhibitory effects were significantly reversed in the presence of small interfering (si)RNA against PPARδ, or by blockade of the TGF-ß or FAK signaling pathways. Furthermore, PPARδ-mediated recovery of FAK phosphorylation suppressed by oxLDL was reversed by SB431542, a specific ALK5 receptor inhibitor, indicating that a TGF-ß/FAK signaling axis is involved in the action of PPARδ. Among the protein kinases activated by oxLDL, p38 mitogen-activated protein kinase was suppressed by ligand-activated PPARδ. In addition, oxLDL-induced expression and translocation of pro-apoptotic or anti-apoptotic factors were markedly affected in the presence of GW501516. Those effects were reversed by PPARδ siRNA, or inhibitors of TGF-ß or FAK, which also suggests that PPARδ exerts its anti-apoptotic effect via a TGF-ß/FAK signaling axis. Taken together, these findings indicate that PPARδ plays an important role in the pathophysiology of disease associated with apoptosis of VSMC, such as atherosclerosis and restanosis.


Asunto(s)
Apoptosis/efectos de los fármacos , Lipoproteínas LDL , Músculo Liso Vascular/efectos de los fármacos , Miocitos del Músculo Liso/efectos de los fármacos , PPAR delta/fisiología , Animales , Apoptosis/genética , Aterosclerosis/genética , Aterosclerosis/patología , Aterosclerosis/prevención & control , Células Cultivadas , Reestenosis Coronaria/genética , Reestenosis Coronaria/patología , Reestenosis Coronaria/prevención & control , Proteína-Tirosina Quinasas de Adhesión Focal/metabolismo , Músculo Liso Vascular/fisiología , Miocitos del Músculo Liso/fisiología , PPAR delta/agonistas , PPAR delta/antagonistas & inhibidores , ARN Interferente Pequeño/farmacología , Ratas , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genética , Tiazoles/farmacología , Factor de Crecimiento Transformador beta/metabolismo
16.
Biosci Biotechnol Biochem ; 79(5): 760-6, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25560618

RESUMEN

Dalbergia odorifera T. Chen (Leguminosae), an indigenous medicinal herb, has been widely used in northern and eastern Asia to treat diverse diseases. Here, we investigated the anti-senescent effects of ethanolic extracts of Dalbergia odorifera (EEDO) in ultraviolet (UV) B-irradiated skin cells. EEDO significantly inhibited UVB-induced senescence of human keratinocytes in a concentration-dependent manner, concomitant with inhibition of reactive oxygen species (ROS) generation. UVB-induced increases in the levels of p53 and p21, biomarkers of cellular senescence, were almost completely abolished in the presence of EEDO. Sativanone, a major constituent of EEDO, also attenuated UVB-induced senescence and ROS generation in keratinocytes, indicating that sativanone is an indexing (marker) molecule for the anti-senescence properties of EEDO. Finally, treatment of EEDO to mice exposed to UVB significantly reduced ROS levels and the number of senescent cells in the skin. Thus, EEDO confers resistance to UVB-induced cellular senescence by inhibiting ROS generation in skin cells.


Asunto(s)
Dalbergia/química , Queratinocitos/efectos de los fármacos , Queratinocitos/efectos de la radiación , Extractos Vegetales/farmacología , Animales , Células Cultivadas , Senescencia Celular/efectos de los fármacos , Niño , Cromatografía Líquida de Alta Presión , Relación Dosis-Respuesta a Droga , Etanol/química , Humanos , Isoflavonas/química , Isoflavonas/farmacología , Ratones Pelados , Extractos Vegetales/química , Protectores contra Radiación/farmacología , Especies Reactivas de Oxígeno , Piel/citología , Piel/efectos de los fármacos , Piel/efectos de la radiación , Protectores Solares/farmacología , Rayos Ultravioleta/efectos adversos
17.
Drug Dev Res ; 76(1): 48-56, 2015 02.
Artículo en Inglés | MEDLINE | ID: mdl-25620496

RESUMEN

Preclinical Research Emerging evidence suggests that Dalbergia odorifera T. Chen (Leguminosae), an indigenous medicinal herb, has therapeutic potential. This study examined the antiwrinkle effects of ethanol extracts of D. odorifera in UVB-irradiated human skin cells. Ethanol extracts of D. odorifera and thier constituents, dalbergin and sativanone, induced expression of collagen type I and transforming growth factor (TGF)-ß1 in human dermal fibroblasts. In HR-1 hairless mice exposed to UVB, the ethanol extract reduced wrinkle formation and skin thickness. This inhibitory effect of ethanol extract was associated with the restoration of collagen type I, TGF-ß1, and elastin to levels approaching those in skin tissues not exposed to UVB, which was accompanied by the reduction of matrix metalloproteinase-2 and upregulation of tissue inhibitors of metalloproteinase (TIMP)-2 and TIMP-3 in skin tissue exposed to UVB. These results suggest that the ethanol extracts prevent some effects of photoaging and maintain skin integrity by regulating the degradation of the extracellular matrix proteins. © 2015 Wiley Periodicals, Inc.

18.
Am J Cancer Res ; 4(6): 674-82, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25520859

RESUMEN

Peroxisome proliferator-activated receptor (PPAR) δ is implicated in the carcinogenesis of several types of cancer. However, the therapeutic efficacy of PPARδ ligands against cancer progression is unclear. Here, we showed that PPARδ modulates the migration and invasion of melanoma cells by up-regulating Snail expression. Activation of PPARδ by GW501516, a specific ligand for PPARδ, significantly increased the migration and invasion of highly metastatic A375SM cells, but not that of low metastatic A375P cells. The migration- and invasion-promoting effects of PPARδ on A375SM cells was associated with increased Snail expression, which was accompanied by a decrease in E-cadherin expression. Furthermore, a significant concentration- and time-dependent increase in the levels of Snail mRNA and protein was observed in A375SM cells (but not A375P cells) treated with GW501516. The effects of GW501516 were almost completely abrogated by a small interfering RNA against PPARδ, suggesting that PPARδ mediates the effects of GW501516. Activation of PPARδ in SK-MEL-2 and SK-MEL-5 (but not SK-MEL-3) melanoma cell lines also led to significant increases in the expression of Snail mRNA and protein, which mirrored the invasive and migratory potential of these cell lines. These results suggest that PPARδ promotes the aggressive phenotype observed in highly metastatic melanoma cells by up-regulating Snail.

19.
J Vasc Res ; 51(3): 221-30, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25116733

RESUMEN

We investigated the role of peroxisome proliferator-activated receptor (PPAR) δ on angiotensin (Ang) II-induced activation of matrix metalloproteinase (MMP)-2 in vascular smooth muscle cells (VSMCs). Activation of PPARδ by GW501516, a specific ligand for PPARδ, attenuated Ang II-induced activation of MMP-2 in a concentration-dependent manner. GW501516 also inhibited the generation of reactive oxygen species in VSMCs treated with Ang II. A marked increase in the mRNA levels of tissue inhibitor of metalloproteinase (TIMP)-2 and -3, endogenous antagonists of MMPs, was also observed in GW501516-treated VSMCs. These effects were markedly reduced in the presence of siRNAs against PPARδ, indicating that the effects of GW501516 are PPARδ dependent. Among the protein kinases inhibited by GW501516, suppression of phosphatidylinositol 3-kinase/Akt signaling was shown to have the greatest effect on activation of MMP-2 in VSMCs treated with Ang II. Concomitantly, GW501516-mediated inhibition of MMP-2 activation in VSMCs treated with Ang II was associated with the suppression of cell migration to levels approaching those in cells not exposed to Ang II. Thus, activation of PPARδ confers resistance to Ang II-induced degradation of the extracellular matrix by upregulating expression of its endogenous inhibitor TIMP and thereby modulating cellular responses to Ang II in vascular cells.


Asunto(s)
Metaloproteinasa 2 de la Matriz/metabolismo , Miocitos del Músculo Liso/metabolismo , PPAR delta/metabolismo , Angiotensina II/farmacología , Animales , Células Cultivadas , Activación Enzimática/efectos de los fármacos , Masculino , Músculo Liso Vascular/metabolismo , Inhibidores de las Quinasa Fosfoinosítidos-3 , Proteínas Proto-Oncogénicas c-akt/antagonistas & inhibidores , Ratas , Transducción de Señal/efectos de los fármacos , Tiazoles
20.
J Dermatol Sci ; 76(1): 44-50, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25149191

RESUMEN

BACKGROUND: Changes in skin connective tissues mediated by ultraviolet (UV) radiation have been suggested to cause the skin wrinkling normally associated with premature aging of the skin. Recent investigations have shown that peroxisome proliferator-activated receptor (PPAR) δ plays multiple biological roles in skin homeostasis. OBJECTIVE: We attempted to investigate whether PPARδ modulates elastin protein levels and secretion of matrix metalloproteinase (MMP)-2 in UVB-irradiated human dermal fibroblasts (HDFs) and mouse skin. METHODS: These studies were undertaken in primary HDFs or HR-1 hairless mice using Western blot analyses, small interfering (si)RNA-mediated gene silencing, and Fluorescence microscopy. RESULTS: In HDFs, UVB irradiation induced increased secretion of MMP-2 and reduced levels of elastin. Activation of PPARδ by GW501516, a ligand specific for PPARδ, markedly attenuated UVB-induced MMP-2 secretion with a concomitant increase in the level of elastin. These effects were reduced by the presence of siRNAs against PPARδ or treatment with GSK0660, a specific inhibitor of PPARδ. Furthermore, GW501516 elicited a dose- and time-dependent increase in the expression of elastin. Modulation of MMP-2 secretion and elastin levels by GW501516 was associated with a reduction in reactive oxygen species (ROS) production in HDFs exposed to UVB. Finally, in HR-1 hairless mice, administration of GW501516 significantly reduced UVB-induced MMP-2 expression with a concomitant increase in elastin levels, and these effects were significantly reduced by the presence of GSK0660. CONCLUSION: Our results suggest that PPARδ-mediated modulation of MMP-2 secretion and elastin expression may contribute to the maintenance of skin integrity by inhibiting ROS generation.


Asunto(s)
Elastina/metabolismo , Fibroblastos/metabolismo , Regulación de la Expresión Génica , Metaloproteinasa 2 de la Matriz/metabolismo , PPAR delta/metabolismo , Piel/metabolismo , Animales , Relación Dosis-Respuesta en la Radiación , Silenciador del Gen , Homeostasis , Humanos , Ratones , Microscopía Fluorescente , ARN Interferente Pequeño/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Sulfonas/química , Tiofenos/química , Rayos Ultravioleta , Cicatrización de Heridas
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