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1.
Sheng Li Xue Bao ; 73(5): 795-804, 2021 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-34708236

RESUMO

Farnesoid X receptor (FXR) has been identified as an inhibitor of platelet function and an inducer of fibrinogen protein complex. However, the regulatory mechanism of FXR in hemostatic system remains incompletely understood. In this study, we aimed to investigate the functions of FXR in regulating antithrombin III (AT III). C57BL/6 mice and FXR knockout (FXR KO) mice were treated with or without GW4064 (30 mg/kg per day). FXR activation significantly prolonged prothrombin time (PT) and activated partial thromboplastin time (APTT), lowered activity of activated factor X (FXa) and concentrations of thrombin-antithrombin complex (TAT) and activated factor II (FIIa), and increased level of AT III, whereas all of these effects were markedly reversed in FXR KO mice. In vivo, hepatic AT III mRNA and protein expression levels were up-regulated in wild-type mice after FXR activation, but down-regulated in FXR KO mice. In vitro study showed that FXR activation induced, while FXR knockdown inhibited, AT III expression in mouse primary hepatocytes. The luciferase assay and ChIP assay revealed that FXR can bind to the promoter region of AT III gene where FXR activation increased AT III transcription. These results suggest FXR activation inhibits coagulation process via inducing hepatic AT III expression in mice. The present study reveals a new role of FXR in hemostatic homeostasis and indicates that FXR might act as a potential therapeutic target for diseases related to hypercoagulation.


Assuntos
Antitrombina III , Hepatócitos , Receptores Citoplasmáticos e Nucleares , Animais , Coagulação Sanguínea , Fígado , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Receptores Citoplasmáticos e Nucleares/genética
2.
Cell Mol Immunol ; 18(11): 2530-2540, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34556823

RESUMO

Immunomodulation is considered a potential therapeutic approach for chronic kidney disease (CKD). Although it has been previously reported that CD4+ T cells contribute to the development of renal fibrosis, the role of MHC class II (MHCII) in the development of renal fibrosis remains largely unknown. The present study reports that the expression of MHCII molecules in renal cortical tubules is upregulated in mouse renal fibrosis models generated by unilateral ureter obstruction (UUO) and folic acid (FA). Proximal tubule epithelial cells (PTECs) are functional antigen-presenting cells that promote the proliferation of CD4+ T cells in an MHCII-dependent manner. PTECs from mice with renal fibrosis had a stronger ability to induce T cell proliferation and cytokine production than control cells. Global or renal tubule-specific ablation of H2-Ab1 significantly alleviated renal fibrosis following UUO or FA treatment. Renal expression of profibrotic genes showed a consistent reduction in H2-Ab1 gene-deficient mouse lines. Moreover, there was a marked increase in renal tissue CD4+ T cells after UUO or FA treatment and a significant decrease following renal tubule-specific ablation of H2-Ab1. Furthermore, renal tubule-specific H2-Ab1 gene knockout mice exhibited higher proportions of regulatory T cells (Tregs) and lower proportions of Th2 cells in the UUO- or FA-treated kidneys. Finally, Immunohistochemistry (IHC) studies showed increased renal expression of MHCII and the profibrotic gene α smooth muscle actin (α-SMA) in CKD patients. Together, our human and mouse data demonstrate that renal tubular MHCII plays an important role in the pathogenesis of renal fibrosis.

3.
Am J Physiol Renal Physiol ; 321(5): F617-F628, 2021 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-34569253

RESUMO

The ligand-activated nuclear receptor, farnesoid X receptor (FXR), plays a pivotal role in regulating renal function. Activation of FXR by its specific agonists exerts renoprotective action in animals with acute kidney injury (AKI). In the present study, we aimed to identify naturally occurring agonists of FXR with potential as therapeutic agents in renal ischemia-reperfusion injury. In vitro and in vivo FXR activation was determined by a dual-luciferase assay, docking analysis, site-directed mutagenesis, and whole kidney transcriptome analysis. Wild-type (WT) and FXR knockout (FXR-/-) mice were used to determine the effect of potential FXR agonist on renal ischemia-reperfusion injury (IRI). We found that alisol B 23-acetate (ABA), a major active triterpenoid extracted from Alismatis rhizoma, a well-known traditional Chinese medicine, can activate renal FXR and induce FXR downstream gene expression in mouse kidney. ABA treatment significantly attenuated renal ischemia-reperfusion-induced AKI in WT mice but not in FXR-/- mice. Our results demonstrate that ABA can activate renal FXR to exert renoprotection against ischemia-reperfusion injury-induced AKI. Therefore, ABA may represent a potential therapeutic agent in the treatment of ischemic AKI.NEW & NOTEWORTHY In the present study, we found that alisol B 23-acetate (ABA), an identified natural farnesoid X receptor (FXR) agonist from the well-known traditional Chinese medicine Alismatis rhizoma, protects against ischemic acute kidney injury (AKI) in an FXR-dependent manner, as reflected by improved renal function, reduced renal tubular apoptosis, ameliorated oxidative stress, and suppressed inflammatory factor expression. Therefore, ABA may have great potential as a novel therapeutic agent in the treatment of AKI in the future.


Assuntos
Injúria Renal Aguda/prevenção & controle , Colestenonas/farmacologia , Medicamentos de Ervas Chinesas/farmacologia , Rim/efeitos dos fármacos , Receptores Citoplasmáticos e Nucleares/agonistas , Traumatismo por Reperfusão/prevenção & controle , Injúria Renal Aguda/metabolismo , Injúria Renal Aguda/patologia , Animais , Apoptose/efeitos dos fármacos , Modelos Animais de Doenças , Células HEK293 , Células Hep G2 , Humanos , Mediadores da Inflamação/metabolismo , Rim/metabolismo , Rim/patologia , Ligantes , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Estresse Oxidativo/efeitos dos fármacos , Receptores Citoplasmáticos e Nucleares/genética , Receptores Citoplasmáticos e Nucleares/metabolismo , Traumatismo por Reperfusão/metabolismo , Traumatismo por Reperfusão/patologia , Transdução de Sinais
4.
Sheng Li Xue Bao ; 73(4): 597-605, 2021 Aug 25.
Artigo em Chinês | MEDLINE | ID: mdl-34405216

RESUMO

Prostaglandin E2 (PGE2) plays an important role in cardiovascular system. PGE2 regulates blood pressure through its 4 G protein coupled receptors, i.e., EP1, EP2, EP3, and EP4. The aim of this study was to investigate the role of EP4 receptors in vascular smooth muscle cells (VSMC) in blood pressure regulation. VSMC-specific human EP4 transgenic (VSMC-hEP4 Tg) mice were generated and genotyped. The systolic blood pressure (SBP) of the VSMC-hEP4 Tg mice and the wild-type (WT) littermates was measured under normal, low-salt (LSD) and high-salt diet (HSD) conditions using a tail-cuff method. Both WT and VSMC-hEP4 Tg mice were administered with a chronic infusion of angiotensin II (Ang II) with an osmotic pump and SBP levels were monitored every week. The mean arterial blood pressure (MAP) of WT and VSMC-hEP4 Tg mice upon Ang II intravenous infusion was measured via carotid arterial catheterization. Ang II-induced vasoconstriction of the mesenteric arterial rings from WT and VSMC-hEP4 Tg mice was measured using the multi myograph system. The effect of PGE1-OH (a selective EP4 agonist) on Ang II-induced phosphorylation of myosin phosphatase target subunit 1 (MYPT1) was detected by Western blot. The effect of two additional EP4 specific agonists (CAY10580 and CAY10598, 0.5 mg/kg) on blood pressure of WT mice was measured by carotid arterial catheterization. The results showed that the VSMC-hEP4 Tg mice were successfully generated and their basal SBP levels were lower than those of WT mice. Although blood pressure levels were significantly altered in WT mice under LSD and HSD, little change was observed in the VSMC-hEP4 Tg mice. After a chronic infusion and an acute intravenous injection of Ang II, SBP levels of VSMC-hEP4 Tg mice were significantly lower than those of WT mice. In addition, both CAY10580 and CAY10598 significantly reduced MAP levels of WT mice. Ex vivo study showed that treatment of isolated mesenteric arteries with PGE1-OH inhibited Ang II-induced phosphorylation of MYPT1. Collectively, these results demonstrate that specific overexpression of human EP4 gene in VSMCs significantly reduces basal blood pressure levels and attenuates Ang II-induced hypertension, possibly via inhibiting Ang II/AT1 signaling pathway. Our findings suggest that EP4 may represent an attractive target for the treatment of hypertension.


Assuntos
Angiotensina II , Hipertensão , Animais , Humanos , Hipertensão/induzido quimicamente , Camundongos , Camundongos Endogâmicos C57BL , Músculo Liso Vascular , Miócitos de Músculo Liso
5.
Sheng Li Xue Bao ; 73(4): 657-664, 2021 Aug 25.
Artigo em Chinês | MEDLINE | ID: mdl-34405221

RESUMO

Arachidonic acid (AA) is an ω-6 polyunsaturated fatty acid, which mainly exists in the cell membrane in the form of phospholipid. Three major enzymatic pathways including the cyclooxygenase (COX), lipoxygenase (LOX) and cytochrome P450 monooxygenase (CYP450) pathways are involved in AA metabolism leading to the generation of a variety of lipid mediators such as prostaglandins, leukotrienes, hydroxyeicosatetraenoic acids (HETEs) and epoxyeicoastrienoic acids (EETs). These bioactive AA metabolites play an important role in the regulation of many physiological processes including the maintenance of liver glucose and lipid homeostasis. As the central metabolic organ, the liver is essential in metabolism of carbohydrates, lipids and proteins, and its dysfunction is associated with the pathogenesis of many metabolic diseases such as type 2 diabetes mellitus, dyslipidemia and nonalcoholic fatty liver disease (NAFLD). This article aims to provide an overview of the enzymatic pathways of AA and discuss the role of AA-derived lipid mediators in the regulation of hepatic glucose and lipid metabolism and their associations with the pathogenesis of major metabolic disorders.


Assuntos
Diabetes Mellitus Tipo 2 , Glucose , Ácido Araquidônico/metabolismo , Glucose/metabolismo , Homeostase , Humanos , Metabolismo dos Lipídeos , Fígado
7.
FASEB J ; 35(5): e21530, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33813752

RESUMO

Circadian clock is involved in regulating most renal physiological functions, including water and electrolyte balance and blood pressure homeostasis, however, the role of circadian clock in renal pathophysiology remains largely unknown. Here we aimed to investigate the role of Bmal1, a core clock component, in the development of renal fibrosis, the hallmark of pathological features in many renal diseases. The inducible Bmal1 knockout mice (iKO) whose gene deletion occurred in adulthood were used in the study. Analysis of the urinary water, sodium and potassium excretion showed that the iKO mice exhibit abolished diurnal variations. In the model of renal fibrosis induced by unilateral ureteral obstruction, the iKO mice displayed significantly decreased tubulointerstitial fibrosis reflected by attenuated collagen deposition and mitigated expression of fibrotic markers α-SMA and fibronectin. The hedgehog pathway transcriptional effectors Gli1 and Gli2, which have been reported to be involved in the pathogenesis of renal fibrosis, were significantly decreased in the iKO mice. Mechanistically, ChIP assay and luciferase reporter assay revealed that BMAL1 bound to the promoter of and activate the transcription of Gli2, but not Gli1, suggesting that the involvement of Bmal1 in renal fibrosis was possibly mediated via Gli2-dependent mechanisms. Furthermore, treatment with TGF-ß increased Bmal1 in cultured murine proximal tubular cells. Knockdown of Bmal1 abolished, while overexpression of Bmal1 increased, Gli2 and the expression of fibrosis-related genes. Collectively, these results revealed a prominent role of the core clock gene Bmal1 in tubulointerstitial fibrosis. Moreover, we identified Gli2 as a novel target of Bmal1, which may mediate the adverse effect of Bmal1 in obstructive nephropathy.


Assuntos
Fatores de Transcrição ARNTL/fisiologia , Fibrose/prevenção & controle , Regulação da Expressão Gênica , Nefropatias/prevenção & controle , Proteínas Circadianas Period/fisiologia , Proteína Gli2 com Dedos de Zinco/antagonistas & inibidores , Animais , Animais Recém-Nascidos , Fibrose/etiologia , Fibrose/metabolismo , Fibrose/patologia , Nefropatias/etiologia , Nefropatias/metabolismo , Nefropatias/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteína Gli2 com Dedos de Zinco/genética , Proteína Gli2 com Dedos de Zinco/metabolismo
8.
Sci Adv ; 7(14)2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33811074

RESUMO

Selective modulation of the heterotrimeric G protein α S subunit-coupled prostaglandin E2 (PGE2) receptor EP2 subtype is a promising therapeutic strategy for osteoporosis, ocular hypertension, neurodegenerative diseases, and cardiovascular disorders. Here, we report the cryo-electron microscopy structure of the EP2-Gs complex with its endogenous agonist PGE2 and two synthesized agonists, taprenepag and evatanepag (CP-533536). These structures revealed distinct features of EP2 within the EP receptor family in terms of its unconventional receptor activation and G protein coupling mechanisms, including activation in the absence of a typical W6.48 "toggle switch" and coupling to Gs via helix 8. Moreover, inspection of the agonist-bound EP2 structures uncovered key motifs governing ligand selectivity. Our study provides important knowledge for agonist recognition and activation mechanisms of EP2 and will facilitate the rational design of drugs targeting the PGE2 signaling system.

9.
Biochim Biophys Acta Mol Basis Dis ; 1867(3): 165996, 2021 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-33127475

RESUMO

Cisplatin-induced acute kidney injury (CAKI) has been recognized as one of the most serious side effects of cisplatin. Pregnane X receptor (PXR) is a ligand-dependent nuclear receptor and serves as a master regulator of xenobiotic detoxification. Increasing evidence also suggests PXR has many other functions including the regulation of cell proliferation, inflammatory response, and glucose and lipid metabolism. In this study, we aimed to investigate the role of PXR in cisplatin-induced nephrotoxicity in mice. CAKI model was performed in wild-type or PXR knockout mice. Pregnenolone 16α­carbonitrile (PCN), a mouse PXR specific agonist, was used for PXR activation. The renal function, biochemical, histopathological and molecular alterations were examined in mouse blood, urine or renal tissues. Whole transcriptome analysis was performed by RNA sequencing. We found that PXR activation significantly attenuated CAKI as reflected by improved renal function, reduced renal tubular apoptosis, ameliorated oxidative and endoplasmic reticulum stress, and suppressed inflammatory gene expression. RNA sequencing analysis revealed that the renoprotective effect of PXR was associated with multiple crucial signaling pathways, especially the PI3K/AKT pathway. In vitro study further revealed that PXR protected against cisplatin-induced apoptosis of cultured proximal tubule cells in a PI3K-dependent manner. Our results demonstrate that PXR activation can preserve renal function in cisplatin-induced AKI and suggest a possibility of PXR as a novel protective target for cisplatin-induced nephrotoxicity.


Assuntos
Injúria Renal Aguda/induzido quimicamente , Injúria Renal Aguda/metabolismo , Antineoplásicos/efeitos adversos , Cisplatino/efeitos adversos , Rim/efeitos dos fármacos , Receptor de Pregnano X/metabolismo , Injúria Renal Aguda/patologia , Animais , Células Cultivadas , Rim/metabolismo , Rim/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fatores de Proteção , Transdução de Sinais/efeitos dos fármacos
10.
Sheng Li Xue Bao ; 72(6): 699-706, 2020 Dec 25.
Artigo em Chinês | MEDLINE | ID: mdl-33349826

RESUMO

Systematic integration teaching is a curriculum system focusing on organs and systems, which is an important direction of medical education reform in China. Based on the practice of integrated curriculum teaching in Dalian Medical University for more than 10 years, combined with the experience in 15 medical colleges and universities in China, this paper analyzed the modes of systematic integrated teaching at the basic medicine teaching stage for medical higher education, and specified the purpose and significance of this teaching reform. The results showed that: (1) The systematic integrated teaching is a well-accepted and widely used teaching mode in domestic medical colleges and universities, which mainly includes three types of methodologies, i.e., integration of basic medicine courses, integration of clinical medicine courses and integration of basic and clinical medicine courses. The systematic integrated teaching is carried out by reforming various teaching methods including problem-based learning (PBL), case-based learning (CBL) and team-based learning (TBL). (2) The systematic integration teaching at the basic medicine teaching stage can significantly optimize the transition between basic and clinical courses, promote the cooperation and exchange between basic and clinical teachers, and improve the medical students' knowledge construction and critical thinking, and teachers' teaching ability as well. (3) The systematic integration teaching concept of "Six focuses" and "Five combinations" effectively guides the design and implementation of the integrated curriculum at the basic medical teaching stage of Dalian Medical University. With the deepening and development of medical education system reform in China, giving full play to the respective advantages of the systematic integrated teaching and traditional single-subject teaching at the basic medicine stage, and strengthening the integration of basic and clinical courses will play an important role in optimizing medical education curriculum system with Chinese characteristics.


Assuntos
Educação Médica , Medicina , Grupo com Ancestrais do Continente Asiático , China , Currículo , Humanos
11.
Pflugers Arch ; 472(11): 1631-1641, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32914211

RESUMO

Crystallin zeta (CRYZ) is a phylogenetically restricted water-soluble protein and provides cytoprotection against oxidative stress via multiple mechanisms. Increasing evidence suggests that CRYZ is high abundantly expressed in the kidney where it acts as a transacting factor in increasing glutaminolysis and the Na+/K+/2Cl- cotransporter (BSC1/NKCC2) expression to help maintain acid-base balance and medullary hyperosmotic gradient. However, the mechanism by which CRYZ is regulated in the kidney remains largely uncharacterized. Here, we show that CRYZ is a direct target of farnesoid X receptor (FXR), a nuclear receptor important for renal physiology. We found that CRYZ was ubiquitously expressed in mouse kidney and constitutively expressed in the cytoplasm of medullary collecting duct cells (MCDs). In primary cultured mouse MCDs, CRYZ expression was significantly upregulated by the activation and overexpression of FXR. FXR-induced CRYZ expression was almost completely abolished in the MCD cells with siRNA-mediated FXR knockdown. Consistently, treatment with FXR agonists failed to induce CRYZ expression in the MCDs isolated from mice with global and collecting duct-specific FXR deficiency. We identified a putative FXR response element (FXRE) on the CRYZ gene promoter. The luciferase reporter and ChIP assays revealed that FXR can bind directly to the FXRE site, which was further markedly enhanced by FXR activation. Furthermore, we found CRYZ overexpression in MCDs significantly attenuated hypertonicity-induced cell death possibly via increasing Bcl-2 expression. Collectively, our findings demonstrate that CRYZ is constitutively expressed in renal medullary collecting duct cells, where it is transcriptionally controlled by FXR. Given a critical role of FXR in MCDs, CRYZ may be responsible for protective effect of FXR on the survival of MCDs under hypertonic condition during dehydration.


Assuntos
Túbulos Renais Coletores/metabolismo , Receptores Citoplasmáticos e Nucleares/metabolismo , zeta-Cristalinas/genética , Animais , Células Cultivadas , Citoplasma/metabolismo , Túbulos Renais Coletores/citologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Pressão Osmótica , Receptores Citoplasmáticos e Nucleares/genética , Elementos de Resposta , zeta-Cristalinas/metabolismo
12.
J Pharmacol Exp Ther ; 375(1): 40-48, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32759273

RESUMO

Deletion of microsomal prostaglandin E2 synthase-1 (mPGES-1) inhibits inflammation and protects against atherosclerotic vascular diseases but displayed variable influence on pathologic cardiac remodeling. Overactivation of ß-adrenergic receptors (ß-ARs) causes heart dysfunction and cardiac remodeling, whereas the role of mPGES-1 in ß-AR-induced cardiac remodeling is unknown. Here we addressed this question using mPGES-1 knockout mice, subjecting them to isoproterenol, a synthetic nonselective agonist for ß-ARs, at 5 or 15 mg/kg per day to induce different degrees of cardiac remodeling in vivo. Cardiac structure and function were assessed by echocardiography 24 hours after the last of seven consecutive daily injections of isoproterenol, and cardiac fibrosis was examined by Masson trichrome stain in morphology and by real-time polymerase chain reaction for the expression of fibrosis-related genes. The results showed that deletion of mPGES-1 had no significant effect on isoproterenol-induced cardiac dysfunction or hypertrophy. However, the cardiac fibrosis was dramatically attenuated in the mPGES-1 knockout mice after either low-dose or high-dose isoproterenol exposure. Furthermore, in vitro study revealed that overexpression of mPGES-1 in cultured cardiac fibroblasts increased isoproterenol-induced fibrosis, whereas knocking down mPGES-1 in cardiac myocytes decreased the fibrogenesis of fibroblasts. In conclusion, mPGES-1 deletion protects against isoproterenol-induced cardiac fibrosis in mice, and targeting mPGES-1 may represent a novel strategy to attenuate pathologic cardiac fibrosis, induced by ß-AR agonists. SIGNIFICANCE STATEMENT: Inhibitors of microsomal prostaglandin E2 synthase-1 (mPGES-1) are being developed as alternative analgesics that are less likely to elicit cardiovascular hazards than cyclooxygenase-2 selective nonsteroidal anti-inflammatory drugs. We have demonstrated that deletion of mPGES-1 protects inflammatory vascular diseases and promotes post-myocardial infarction survival. The role of mPGES-1 in ß-adrenergic receptor-induced cardiomyopathy is unknown. Here we illustrated that deletion of mPGES-1 alleviated isoproterenol-induced cardiac fibrosis without deteriorating cardiac dysfunction. These results illustrated that targeting mPGES-1 may represent an efficacious approach to the treatment of inflammatory cardiovascular diseases.


Assuntos
Cardiomiopatias/genética , Microssomos/metabolismo , Miocárdio/patologia , Prostaglandina-E Sintases/genética , Receptores Adrenérgicos beta/metabolismo , Remodelação Ventricular/genética , Agonistas Adrenérgicos beta/farmacologia , Animais , Cardiomiopatias/metabolismo , Cardiomiopatias/patologia , Células Cultivadas , Feminino , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Fibrose , Isoproterenol/farmacologia , Masculino , Camundongos Knockout , Microssomos/efeitos dos fármacos , Miocárdio/metabolismo , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Ratos , Ratos Sprague-Dawley , Remodelação Ventricular/efeitos dos fármacos
13.
Front Immunol ; 11: 1224, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32636842

RESUMO

Increased serum IgE level is one of the features of allergic asthma. It is reported that IgE production can be enhanced by E-prostanoid 2 (EP2) receptor of prostaglandin E2 (PGE2); however, whether E-prostanoid 4 (EP4) receptor (encoded by Ptger4) has a unique or redundant role is still unclear. Here, we demonstrated the mice with B cell-specific deletion of the EP4 receptor (Ptger4 fl/fl Mb1 cre+/-) showed their serum levels of IgE were markedly increased. A much more severe airway allergic inflammation was observed in the absence of EP4 signal using the OVA-induced asthma model. Mechanistic studies demonstrated that the transcription levels of AID, GLTε, and PSTε in EP4-deficient B cells were found to be significantly increased, implying an enhanced IgE class switch. In addition, we saw higher levels of phosphorylated STAT6, a vital factor for IgE class switch. Biochemical analyses indicated that inhibitory effect of EP4 signal on IgE depended on the activation of the PI3K-AKT pathway. Further downstream, PPARγ expression was up-regulated. Independent of its activity as a transcription factor, PPARγ here primarily functioned as an E3 ubiquitin-ligase, which bound the phosphorylated STAT6 to initiate its degradation. In support of PPARγ as a key mediator downstream of the EP4 signal, PPARγ agonist induced the down-regulation of phospho-STAT6, whereas its antagonist was able to rescue the EP4-mediated inhibition of STAT6 activation and IgE production. Thus, our findings highlight a role for the PGE2-EP4-AKT-PPARγ-STAT6 signaling in IgE response, highlighting the therapeutic potential of combined application of EP4 and PPARγ agonists in asthma.


Assuntos
Asma/metabolismo , Dinoprostona/metabolismo , Switching de Imunoglobulina/imunologia , Imunoglobulina E/biossíntese , PPAR gama/metabolismo , Animais , Asma/imunologia , Dinoprostona/imunologia , Imunoglobulina E/imunologia , Camundongos , Camundongos Endogâmicos C57BL , PPAR gama/imunologia , Estabilidade Proteica , Receptores de Prostaglandina E Subtipo EP4/deficiência , Receptores de Prostaglandina E Subtipo EP4/imunologia , Fator de Transcrição STAT6/metabolismo , Transdução de Sinais/imunologia
14.
JCI Insight ; 5(13)2020 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-32641583

RESUMO

Prostaglandin E2 and its cognate EP1-4 receptors play important roles in blood pressure (BP) regulation. Herein, we show that endothelial cell-specific (EC-specific) EP4 gene-knockout mice (EC-EP4-/-) exhibited elevated, while EC-specific EP4-overexpression mice (EC-hEP4OE) displayed reduced, BP levels compared with the control mice under both basal and high-salt diet-fed conditions. The altered BP was completely abolished by treatment with l-NG-nitro-l-arginine methyl ester (l-NAME), a competitive inhibitor of endothelial nitric oxide synthase (eNOS). The mesenteric arteries of the EC-EP4-/- mice showed increased vasoconstrictive response to angiotensin II and reduced vasorelaxant response to acetylcholine, both of which were eliminated by l-NAME. Furthermore, EP4 activation significantly reduced BP levels in hypertensive rats. Mechanistically, EP4 deletion markedly decreased NO contents in blood vessels via reducing eNOS phosphorylation at Ser1177. EP4 enhanced NO production mainly through the AMPK pathway in cultured ECs. Collectively, our findings demonstrate that endothelial EP4 is essential for BP homeostasis.


Assuntos
Pressão Sanguínea/fisiologia , Endotélio Vascular/metabolismo , Homeostase/fisiologia , Óxido Nítrico Sintase Tipo III/metabolismo , Receptores de Prostaglandina E Subtipo EP4/metabolismo , Animais , Pressão Sanguínea/efeitos dos fármacos , Dinoprostona/metabolismo , Dinoprostona/farmacologia , Células Endoteliais/metabolismo , Homeostase/efeitos dos fármacos , Hipertensão/metabolismo , Camundongos Transgênicos , NG-Nitroarginina Metil Éster/metabolismo , NG-Nitroarginina Metil Éster/farmacologia
15.
Exp Cell Res ; 390(1): 111949, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32145254

RESUMO

Farnesoid X receptor (FXR) is a metabolic nuclear receptor, which protects liver from many endogenous and exogenous injuries. Metallothioneins (MTs) belong to a low-molecular-weight protein family involved in metal homeostasis and the regulation of hepatic oxidative stress. In the present study, we aimed to investigate the effect of FXR on hepatic MT1 expression and the underlying mechanism. C57BL/6 mice or primary cultured mouse hepatocytes were treated with the synthetic FXR ligand GW4064 or natural ligand CDCA. RNA-Sequencing (RNA-seq) analysis was performed to identify gene expression profile in the livers of mice treated with GW4064. Real-time PCR and Western blot were applied to determine the expression of MT1 and other FXR target genes in the livers of mice and primary hepatocytes treated with GW4064 and CDCA. Cellular and subcellular locations of MT1 in the livers of mice treated with GW4064 were examined using immunohistochemistry assay. FXR small interfering RNAs (siRNA) was transfected to silence FXR. Luciferase reporter and chromatin immunoprecipitation (ChIP) assays were utilized to confirm the regulation of MT1 gene promoter activity by FXR. RNA-seq analysis revealed that GW4064 treatment significantly induced MT1 expression in mouse liver. Consistently, MT1 expression in the hepatocytes of mouse livers and cultured hepatocytes was upregulated by GW4064 as well as CDCA. In addition, adenovirus-mediated overexpression of FXR markedly increased, while siRNA-mediated FXR silencing significantly suppressed MT1 expression in cultured hepatocytes. Luciferase reporter and ChIP assays further confirmed that the MT1 gene was under the direct control of FXR. Collectively, our findings demonstrate that MT1 is a novel target gene of FXR and may contribute to antioxidative capacity of FXR in liver diseases.


Assuntos
Fígado/metabolismo , Metalotioneína/genética , Receptores Citoplasmáticos e Nucleares/metabolismo , Animais , Células Cultivadas , Hepatócitos/metabolismo , Humanos , Masculino , Metalotioneína/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Receptores Citoplasmáticos e Nucleares/genética
16.
Am J Physiol Renal Physiol ; 318(1): F193-F203, 2020 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-31682170

RESUMO

The kidney is the central organ involved in maintaining water and sodium balance. In human kidneys, nine aquaporins (AQPs), including AQP1-8 and AQP11, have been found and are differentially expressed along the renal tubules and collecting ducts with distinct and critical roles in the regulation of body water homeostasis and urine concentration. Dysfunction and dysregulation of these AQPs result in various water balance disorders. This review summarizes current understanding of physiological and pathophysiological roles of AQPs in the kidney, with a focus on recent progress on AQP2 regulation by the nuclear receptor transcriptional factors. This review also provides an overview of AQPs as clinical biomarkers and therapeutic targets for renal diseases.


Assuntos
Aquaporinas/metabolismo , Nefropatias/metabolismo , Rim/metabolismo , Equilíbrio Hidroeletrolítico/fisiologia , Animais , Homeostase/fisiologia , Humanos
18.
Sheng Li Xue Bao ; 71(3): 491-496, 2019 Jun 25.
Artigo em Chinês | MEDLINE | ID: mdl-31218341

RESUMO

Adipose tissue is the energy storage organ of the body, and excess energy is stored in adipocytes in the form of lipid droplets. The homeostasis of adipose tissue is the basis for the body to maintain normal metabolic activity. Prostaglandin E2 (PGE2) is an important lipid mediator in the body. It is synthesized in almost all tissues and participates in the regulation of many physiological processes such as blood pressure, glucose and lipid metabolism, and inflammation. PGE2 is abundant in white adipose tissue, where it is involved in the regulation of fat metabolism. PGE2 plays its biological role through binding to four G protein coupled receptors (prostaglandin E2 receptors), including EP-1, -2, -3, and -4. The EP4 subtype has been proved to play an important role in adipogenesis and adipose metabolism: it could inhibit adipogenesis while it was activated, whereas its knockout could promote lipolysis. This review summarized the relationship between EP4 and adipose metabolism, hoping to identify new targets of drug development for metabolic disorders.


Assuntos
Adipogenia , Tecido Adiposo/metabolismo , Receptores de Prostaglandina E Subtipo EP4/fisiologia , Adipócitos , Humanos
19.
Proc Natl Acad Sci U S A ; 116(17): 8457-8462, 2019 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-30948641

RESUMO

Prostaglandin E2 (PGE2) plays an important role in vascular homeostasis. Its receptor, E-prostanoid receptor 4 (EP4) is essential for physiological remodeling of the ductus arteriosus (DA). However, the role of EP4 in pathological vascular remodeling remains largely unknown. We found that chronic angiotensin II (AngII) infusion of mice with vascular smooth muscle cell (VSMC)-specific EP4 gene knockout (VSMC-EP4-/-) frequently developed aortic dissection (AD) with severe elastic fiber degradation and VSMC dedifferentiation. AngII-infused VSMC-EP4-/- mice also displayed more profound vascular inflammation with increased monocyte chemoattractant protein-1 (MCP-1) expression, macrophage infiltration, matrix metalloproteinase-2 and -9 (MMP2/9) levels, NADPH oxidase 1 (NOX1) activity, and reactive oxygen species production. In addition, VSMC-EP4-/- mice exhibited higher blood pressure under basal and AngII-infused conditions. Ex vivo and in vitro studies further revealed that VSMC-specific EP4 gene deficiency significantly increased AngII-elicited vasoconstriction of the mesenteric artery, likely by stimulating intracellular calcium release in VSMCs. Furthermore, EP4 gene ablation and EP4 blockade in cultured VSMCs were associated with a significant increase in MCP-1 and NOX1 expression and a marked reduction in α-SM actin (α-SMA), SM22α, and SM differentiation marker genes myosin heavy chain (SMMHC) levels and serum response factor (SRF) transcriptional activity. To summarize, the present study demonstrates that VSMC EP4 is critical for vascular homeostasis, and its dysfunction exacerbates AngII-induced pathological vascular remodeling. EP4 may therefore represent a potential therapeutic target for the treatment of AD.


Assuntos
Aneurisma Dissecante/metabolismo , Angiotensina II/metabolismo , Pressão Sanguínea/fisiologia , Inflamação/metabolismo , Receptores de Prostaglandina E Subtipo EP4 , Animais , Aorta/química , Aorta/metabolismo , Aneurisma Aórtico/metabolismo , Dinoprostona/metabolismo , Feminino , Hipertensão/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Músculo Liso Vascular/metabolismo , Receptores de Prostaglandina E Subtipo EP4/genética , Receptores de Prostaglandina E Subtipo EP4/metabolismo , Remodelação Vascular/genética
20.
Sheng Li Xue Bao ; 71(2): 311-318, 2019 Apr 25.
Artigo em Chinês | MEDLINE | ID: mdl-31008491

RESUMO

As a member of the nuclear receptor superfamily, the pregnane X receptor (PXR) is a ligand-activated transcription factor. PXR is highly expressed in liver and intestinal tissues, and also found in other tissues and organs, such as stomach and kidney. After heterodimerization with retinoid X receptor (RXR), PXR recruits numerous co-activating factors, and binds to specific DNA response elements to perform transcriptional regulation of the downstream target genes. As an acknowledged receptor for xenobiotics, PXR was initially considered as a nuclear receptor regulating drug metabolizing enzymes and transporters. However, nowadays, PXR has also been recognized as an important endobiotic receptor. Recent studies have shown that PXR activation can regulate glucose metabolism, lipid metabolism, steroid endocrine homeostasis, detoxification of cholic acid and bilirubin, bone mineral balance, and immune inflammation in vivo. This review focuses on the role of PXR in metabolism of endogenous substances.


Assuntos
Receptor de Pregnano X/metabolismo , Xenobióticos/metabolismo , Animais , Regulação da Expressão Gênica , Humanos
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