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1.
Pediatr Pulmonol ; 2024 May 02.
Article in English | MEDLINE | ID: mdl-38695576

ABSTRACT

OBJECTIVE: Recent evidence suggests that alexithymic deficits in emotional processing may also affect physical health, and alexithymia may also be associated with organic disorders. The emotional well-being of patients with primary ciliary dyskinesia (PCD) is often negatively affected by uncertainty about the prognosis, lack of ongoing medical care, and lack of symptom control. This study aims to evaluate the frequency of alexithymia and its possible impact on the management of childhood PCD. MATERIALS AND METHODS: Subjects were recruited from patients with PCD and healthy volunteers aged 8-18 years. The questionnaire included sociodemographic characteristics and self-report scales. Data were compared between patient and control groups. RESULTS: In the >14 years of age group, the total Toronto Alexithymia Scale (TAS-20) score was significantly higher in the patients (56.60 ± 13.01) compared to the control group (46.47 ± 7.50) (p = .007). There were 6 (30) patients with a TAS-20 score ≥61. There was a significant correlation between TAS-20 and Pediatric Quality of Life (PedsQL) score (child), but no correlation between TAS-20 and Kovacs Children Depression Inventory (CDI) and PedsQL score (parents). The TAS-20 score was significantly higher in patients with bronchiectasis (p = .035), nasal polyps (p = .045), and siblings with PCD (p = .001). Furthermore, the TAS-20 score had a significant negative correlation with pulmonary function tests. CONCLUSION: Although this study is based on limited data from a single center and cannot be generalized to all PCD patient communities, our results show that PCD patients are more likely to have alexithymia compared to healthy controls and highlight the need to evaluate for alexithymia in patients with PCD. It is important for pediatric pulmonologists to have a thorough knowledge of the alexithymic features associated with PCD and to refer patients to pediatric psychiatry when necessary, especially in patients who are noncompliant with treatment protocols.

2.
Biochem Biophys Res Commun ; 693: 149370, 2024 Jan 22.
Article in English | MEDLINE | ID: mdl-38100998

ABSTRACT

CD146/MCAM has garnered significant attention for its potential contribution to cardiovascular disease; however, the transcriptional regulation and functions remain unclear. To explore these processes regarding cardiomyopathy, we employed doxorubicin, a widely used stressor for cardiomyocytes. Our in vitro study on H9c2 cardiomyoblasts highlights that, besides impairing the fatty acid uptake in the cells, doxorubicin suppressed the expression of fatty acid binding protein 4 (Fabp4) along with the histone deacetylase 9 (Hdac9), bromodomain and extra-terminal domain proteins (BETs: Brd2 and Brd4), while augmented the production of CD146/MCAM. Silencing and chemical inhibition of Hdac9 further augmented CD146/MCAM and deteriorated fatty acid uptake. In contrast, chemical inhibition of BETs as well as silencing of MCAM/CD146 ameliorated fatty acid uptake. Moreover, protein kinase C (PKC) inhibition abrogated CD146/MCAM, particularly in the nucleus. Taken together, our results suggest that epigenetic dysregulation of Hdac9, Brd2, and Brd4 alters CD146/MCAM expression, deteriorating fatty acid uptake by downregulating Fabp4. This process depends on the PKC-mediated nuclear translocation of CD146. Thus, this study highlights a pivotal role of CD146/MCAM in doxorubicin-induced cardiomyopathy.


Subject(s)
Cardiomyopathies , Transcription Factors , Humans , CD146 Antigen/genetics , CD146 Antigen/metabolism , Transcription Factors/genetics , Transcription Factors/metabolism , Nuclear Proteins/genetics , Nuclear Proteins/metabolism , Epigenesis, Genetic
3.
Kidney Blood Press Res ; 48(1): 326-337, 2023.
Article in English | MEDLINE | ID: mdl-37019097

ABSTRACT

INTRODUCTION: While recent investigations show that klotho exerts renoprotective actions, it has not been fully addressed whether klotho protein supplementation reverses renal damage. METHODS: The impacts of subcutaneous klotho supplementation on rats with subtotal nephrectomy were examined. Animals were divided into 3 groups: group 1 (short remnant [SR]): remnant kidney for 4 weeks, group 2 (long remnant [LR]): remnant kidney for 12 weeks, and group 3 (klotho supplementation [KL]): klotho protein (20 µg/kg/day) supplementation on the remnant kidney. Blood pressure, blood and urine compositions with conventional methods such as enzyme-linked immunosorbent assay and radioimmunoassay, kidney histology, and renal expressions of various genes were analyzed. In vitro studies were also performed to support in vivo findings. RESULTS: Klotho protein supplementation decreased albuminuria (-43%), systolic blood pressure (-16%), fibroblast growth factor (FGF) 23 (-51%) and serum phosphate levels (-19%), renal angiotensin II concentration (-43%), fibrosis index (-70%), renal expressions of collagen I (-55%), and transforming growth factor ß (-59%) (p < 0.05 for all). Klotho supplementation enhanced fractional excretion of phosphate (+45%), glomerular filtration rate (+76%), renal expressions of klotho (+148%), superoxide dismutase (+124%), and bone morphogenetic protein (BMP) 7 (+174%) (p < 0.05 for all). CONCLUSION: Our data indicated that klotho protein supplementation inactivated renal renin-angiotensin system, reducing blood pressure and albuminuria in remnant kidney. Furthermore, exogenous klotho protein supplementation elevated endogenous klotho expression to increase phosphate excretion with resultant reductions in FGF23 and serum phosphate. Finally, klotho supplementation reversed renal dysfunction and fibrosis in association with improved BMP7 in remnant kidney.


Subject(s)
Albuminuria , Kidney Diseases , Animals , Rats , Albuminuria/metabolism , Dietary Supplements , Fibrosis , Kidney/pathology , Kidney Diseases/pathology , Klotho Proteins/therapeutic use , Phosphates/metabolism
6.
J Hypertens ; 39(8): 1567-1576, 2021 08 01.
Article in English | MEDLINE | ID: mdl-33758157

ABSTRACT

BACKGROUND: Klotho interacts with various membrane proteins, such as transforming growth factor-ß (TGFß) and insulin-like growth factor (IGF) receptors. The renal expression of klotho is diminished in chronic kidney disease. METHOD: In this study, we assessed the effects of klotho supplementation on a murine model of IgA nephropathy. Twenty-four-week-old hyper serum IgA (HIGA) mice were subcutaneously injected daily with recombinant human klotho protein (20 µg/kg per day) or the vehicle. After 2 months, the mice were killed using an anesthesia overdose and their kidneys were harvested for analysis. RESULTS: Supplementation of exogenous klotho protein reduced SBP, albuminuria, 8-epi-prostaglandin F2α excretion, glomerular filtration rate, renal angiotensin II concentration, and angiotensinogen expression in HIGA mice. Additionally, it enhanced renal expression of superoxide dismutase (SOD) and renal klotho itself. The findings using laser-manipulated microdissection demonstrated that klotho supplementation reduced the glomerular expression of TGFß, fibronectin, and IGF, and increased the glomerular expression of connexin (Cx) 40. CONCLUSION: These results indicate that klotho supplementation reduces blood pressure by suppressing the renin--angiotensin system in HIGA mice. Klotho inhibits IGF signaling to preserve glomerular Cx40 levels, ameliorating albuminuria in HIGA mice. Klotho protein supplementation attenuates mesangial expansion by inhibiting TGFß signaling in HIGA mice.


Subject(s)
Glomerulonephritis, IGA , Glucuronidase , Albuminuria , Animals , Blood Pressure , Dietary Supplements , Disease Models, Animal , Glomerulonephritis, IGA/drug therapy , Klotho Proteins , Mice
7.
Mol Cancer Ther ; 19(9): 1844-1855, 2020 09.
Article in English | MEDLINE | ID: mdl-32669314

ABSTRACT

We previously reported that silencing of the PRR gene, which encodes the (pro)renin receptor [(P)RR], significantly reduced Wnt/ß-catenin-dependent development of pancreatic ductal adenocarcinoma (PDAC). Here, we examined the effects of a panel of blocking mAbs directed against the (P)RR extracellular domain on proliferation of the human PDAC cell lines PK-1 and PANC-1 in vitro and in vivo We observed that four rat anti-(P)RR mAbs induced accumulation of cells in the G0-G1-phase of the cell cycle and significantly reduced proliferation in vitro concomitant with an attenuation of Wnt/ß-catenin signaling. Systemic administration of the anti-(P)RR mAbs to nude mice bearing subcutaneous PK-1 xenografts significantly decreased tumor expression of active ß-catenin and the proliferation marker Ki-67, and reduced tumor growth. In contrast, treatment with the handle region peptide of (pro)renin did not inhibit tumor growth in vitro or in vivo, indicating that the effects of the anti-(P)RR mAbs were independent of the renin-angiotensin system. These data indicate that mAbs against human (P)RR can suppress PDAC cell proliferation by hindering activation of the Wnt/ß-catenin signaling pathway. Thus, mAb-mediated (P)RR blockade could be an attractive therapeutic strategy for PDAC.


Subject(s)
Antibodies, Monoclonal/administration & dosage , Antineoplastic Agents, Immunological/administration & dosage , Carcinoma, Pancreatic Ductal/drug therapy , Pancreatic Neoplasms/drug therapy , Receptors, Cell Surface/chemistry , Vacuolar Proton-Translocating ATPases/chemistry , Animals , Antibodies, Monoclonal/pharmacology , Antineoplastic Agents, Immunological/pharmacology , Carcinoma, Pancreatic Ductal/metabolism , Cell Cycle/drug effects , Cell Line, Tumor , Cell Proliferation/drug effects , Gene Expression Regulation, Neoplastic/drug effects , HEK293 Cells , Humans , Male , Mice , Pancreatic Neoplasms/metabolism , Protein Domains , Rats , Receptors, Cell Surface/antagonists & inhibitors , Vacuolar Proton-Translocating ATPases/antagonists & inhibitors , Wnt Signaling Pathway/drug effects , Xenograft Model Antitumor Assays
9.
Int J Mol Sci ; 20(2)2019 Jan 17.
Article in English | MEDLINE | ID: mdl-30658440

ABSTRACT

The human gastrointestinal tract is inhabited by many types of microbiota, including bacteria, viruses, and fungi. Dysregulations of their microenvironment are associated with various health problems, not only limited to gastrointestinal disorders, such as inflammatory bowel disease, but to impacts beyond the intestine. For example, intestinal microbiota can affect the liver in non-alcoholic fatty liver disease, visceral adipose tissue during adipogenesis, and the heart in atherosclerosis. The factors contributing to these pathogeneses involve the gut microbiota and the effector organs of the host, and everything in between. The nuclear receptor peroxisome proliferator-activated receptors (PPARs) are pivotal for the modulation of many of the pathogeneses mentioned above. It is, therefore, conceivable that, in the process of host-microbiota interactions, PPARs play important roles. In this review, we focus on the interactions between host PPARs in different organs and gut microbiota and their impacts on maintaining health and various diseases.


Subject(s)
Disease Susceptibility , Gastrointestinal Microbiome , Host-Pathogen Interactions , Peroxisome Proliferator-Activated Receptors/metabolism , Adaptation, Biological , Animals , Energy Metabolism , Gene Expression Regulation , Humans , Immunomodulation , Peroxisome Proliferator-Activated Receptors/genetics , Signal Transduction
10.
Int J Mol Sci ; 19(2)2018 Jan 30.
Article in English | MEDLINE | ID: mdl-29385702

ABSTRACT

The morning surge in blood pressure (BP) coincides with increased cardiovascular (CV) events. This strongly suggests that an altered circadian rhythm of BP plays a crucial role in the development of CV disease (CVD). A disrupted circadian rhythm of BP, such as the non-dipping type of hypertension (i.e., absence of nocturnal BP decline), is frequently observed in metabolic disorders and chronic kidney disease (CKD). The circadian timing system, controlled by the central clock in the suprachiasmatic nucleus of the hypothalamus and/or by peripheral clocks in the heart, vasculature, and kidneys, modulates the 24 h oscillation of BP. However, little information is available regarding the molecular and cellular mechanisms of an altered circadian timing system-mediated disrupted dipping pattern of BP in metabolic disorders and CKD that can lead to the development of CV events. A more thorough understanding of this pathogenesis could provide novel therapeutic strategies for the management of CVD. This short review will address our and others' recent findings on the molecular mechanisms that may affect the dipping pattern of BP in metabolic dysfunction and kidney disease and its association with CV disorders.


Subject(s)
Blood Pressure , Cardiovascular Diseases/physiopathology , Circadian Rhythm , Kidney Diseases/physiopathology , Cardiovascular Diseases/pathology , Cardiovascular Diseases/therapy , Humans , Kidney Diseases/pathology , Kidney Diseases/therapy
11.
J Cell Biochem ; 119(6): 4627-4635, 2018 06.
Article in English | MEDLINE | ID: mdl-29266408

ABSTRACT

Proper balance between lipolysis and lipogenesis in adipocytes determines the release of free fatty acids (FFA) and glycerol, which is crucial for whole body lipid homeostasis. Although, dysregulation of lipid homeostasis contributes to various metabolic complications such as insulin resistance, the regulatory mechanism remains elusive. This study clarified the individual and combined roles for glucocorticoid receptor (GCR) and peroxisome proliferator-activated receptor (PPAR)γ pathways in lipid metabolism of adipocytes. In mature 3T3-L1 adipocytes, GCR activation using dexamethasone upregulated adipose triglyceride lipase (ATGL) and downregulated phosphoenolpyruvate carboxykinase (PEPCK), resulting in enhanced glycerol release into the medium. In contrast, PPARγ ligand pioglitazone modestly upregulated ATGL and hormone sensitive lipase (HSL), but markedly enhanced PEPCK and glycerol kinase (GK), thereby suppressed glycerol release. Dexamethasone showed permissive like effect on PPARγ target genes including perilipin A and aP2, therefore co-administration of dexamethasone and pioglitazone demonstrated synergistic upregulation of these enzymes excepting PEPCK, of which downregulation by dexamethasone was abolished by pioglitazone to the level above control. Thus, the excessive glycerol release was prevented as the net outcome of the co-administration. Consistently, the bodipy stain demonstrated that dexamethasone reduced the amount of cytosolic lipid, which was preserved in co-treated adipocytes. Moreover, silencing of PPARγ suppressed the synergistic effects of co-treatment on the lipolytic and lipogenic genes, and therefore the GCR pathway indeed involves PPARγ. In conclusion, crosstalk between GCR and PPARγ is largely synergistic but counter-regulatory in lipogenic genes, of which enhancement prevents excessive glycerol and possibly FFA release by glucocorticoids into the circulation.


Subject(s)
Adipocytes/metabolism , Lipolysis , PPAR gamma/metabolism , Receptors, Glucocorticoid/metabolism , 3T3-L1 Cells , Adipocytes/cytology , Animals , Dexamethasone/pharmacology , Mice , PPAR gamma/genetics , Pioglitazone/pharmacology , Receptors, Glucocorticoid/agonists , Receptors, Glucocorticoid/genetics
12.
Exp Cell Res ; 358(2): 343-351, 2017 09 15.
Article in English | MEDLINE | ID: mdl-28689812

ABSTRACT

Hypoxia predisposes renal fibrosis. This study was conducted to identify novel approaches to ameliorate the pathogenic effect of hypoxia. Using human proximal tubular epithelial cells we showed that a pan-phosphodiesterase (PDE) inhibitor, 3-isobutyl-1-methylxanthine (IBMX) dose and time dependently downregulated hypoxia-inducible factor 1α (HIF-1α) mRNA expression, which was further augmented by addition of a transcriptional inhibitor, actinomycin D. IBMX also increased the cellular cyclic adenosine monophosphate (cAMP) level. Luciferase assay showed that blocking of protein kinase A (PKA) using H89 reduced, while 8-Br-cAMP agonized the repression of HIF-1α promoter activity in hypoxic condition. Deletion of cAMP response element binding sites from the HIF-1α promoter abrogated the effect of IBMX. Western blot and immunofluorescent study confirmed that the CoCl2 induced increased HIF-1α protein in whole cell lysate and in nucleus was reduced by the IBMX. Through this process, IBMX attenuated both CoCl2 and hypoxia induced mRNA expressions of two pro-fibrogenic factors, platelet-derived growth factor B and lysyl oxidase. Moreover, IBMX reduced production of a mesenchymal transformation factor, ß-catenin; as well as protected against hypoxia induced cell-death. Taken together, our study showed novel evidence that the PDE inhibitor IBMX can downregulate the transcription of HIF-1α, and thus may attenuate hypoxia induced renal fibrosis.


Subject(s)
1-Methyl-3-isobutylxanthine/pharmacology , Epithelial Cells/drug effects , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Cell Hypoxia/drug effects , Cells, Cultured , Cyclic AMP-Dependent Protein Kinases/metabolism , Epithelial Cells/metabolism , Humans , Proto-Oncogene Proteins c-sis/metabolism , Signal Transduction/drug effects , Xanthines/pharmacology , beta Catenin/metabolism
14.
Biochem Biophys Res Commun ; 486(1): 76-82, 2017 04 22.
Article in English | MEDLINE | ID: mdl-28263744

ABSTRACT

How nutritional excess leads to inflammatory responses in metabolic syndrome is not well characterized. Here, we evaluated the effects of ω-3 polyunsaturated fatty acid specific G-protein coupled receptor 120 (GPR120) activation on inflammatory pathways in adipocytes, and the influence of this process on macrophage migration. Using 3T3-L1 adipocytes, we found that agonizing GPR120 using its synthetic ligand, GSK137647, attenuated both basal and lipopolysaccharide-induced production of interleukin-6 (IL-6) and C-C motif chemokine ligand 2 (CCL2). Moreover, the intervention reduced the phosphorylation of nuclear factor kappa B inhibitor alpha (IκBα) and nuclear translocation of nuclear factor kappa-B p65 subunit (p65). Furthermore, the silencing of GPR120 itself reduced IL-6 and CCL2 mRNA expression. Inhibition of protein kinase C (PKC) augmented the down-regulatory effect of GSK137647 on IL-6 and CCL2 mRNA. Using a luciferase assay to measure promoter activity of the IL-6 gene in mouse embryonic fibroblasts, we demonstrated that exogenous transfection of GPR120 alone reduced the promoter activity, which was augmented by GSK137647. Inhibition of PKC further reduced the promoter activity. Nevertheless, RAW 264.7 macrophages grown in conditioned medium collected from GSK137647-treated adipocytes attenuated the expressions of matrix metalloproteinases-9 and -3, and tissue inhibitor of metalloproteinase-1. Conditioned medium also inhibited the lipopolysaccharide-induced migration of these macrophages. Taken together, these findings provide critical evidence that although GPR120 is associated with a PKC-mediated pro-inflammatory pathway, the direct inhibitory effects of GPR120 on the nuclear factor kappa B pathway are anti-inflammatory. Moreover, GPR120 activity can attenuate the adipocyte-mediated enhanced production of extracellular matrix-modulating factors in macrophages and can reduce their migration by a paracrine mechanism.


Subject(s)
Adipocytes/metabolism , Adipokines/metabolism , Inflammation Mediators/metabolism , Receptors, G-Protein-Coupled/metabolism , 3T3-L1 Cells , Adipocytes/drug effects , Adipokines/genetics , Animals , Blotting, Western , Cell Line , Cell Movement/drug effects , Cells, Cultured , Chemokine CCL2/genetics , Chemokine CCL2/metabolism , Interleukin-6/genetics , Interleukin-6/metabolism , Lipopolysaccharides/pharmacology , Macrophages/cytology , Macrophages/drug effects , Macrophages/metabolism , Matrix Metalloproteinase 3/genetics , Matrix Metalloproteinase 3/metabolism , Matrix Metalloproteinase 9/genetics , Matrix Metalloproteinase 9/metabolism , Mice , NF-KappaB Inhibitor alpha/metabolism , Phosphorylation/drug effects , Protein Kinase C/metabolism , RNA Interference , Receptors, G-Protein-Coupled/agonists , Receptors, G-Protein-Coupled/genetics , Reverse Transcriptase Polymerase Chain Reaction , Tissue Inhibitor of Metalloproteinase-1/genetics , Tissue Inhibitor of Metalloproteinase-1/metabolism , Transcription Factor RelA/metabolism
15.
Biogerontology ; 18(1): 55-68, 2017 02.
Article in English | MEDLINE | ID: mdl-27734200

ABSTRACT

Deterioration of adipocyte function due to increased oxidative stress predisposes patients to metabolic disorders in advanced age. However, the roles of tumor suppressors in such conditions remain largely unknown. Therefore, we aimed to address their dynamics in aged adipocytes using a long-term culture model. We compared 3T3-L1 adipocytes at 17-19 days (long-term) with those at 8-10 days (short-term) after initiation of adipogenic induction for mimicking 'aged' and 'young' adipocytes, respectively. H2O2 release and dihydroethidium (DHE) staining was increased, while superoxide dismutase (SOD) activity was reduced in long-term cultured adipocytes, which is suggestive of enhanced oxidative stress in this group. Moreover, qRT-PCR revealed increased mRNAs of Nox4 (a subunit of NADPH oxidase complex), Ccl2 (a proinflammatory chemokine) and Il6 [a marker of senescence-associated secretory phenotype (SASP)] along with decreased levels of Pparγ, Adipoq and Slc2a4 (genes related to glucose metabolism). These alterations were associated with increased expression of the tumor suppressors alternate-reading-frame protein p19Arf (Arf) and p16Ink4a. However, silencing of Arf reduced mRNAs of Adipoq and Slc2a4 and enhanced release of Il6. The effect was opposite in Arf overexpressing adipocytes, which showed reduced superoxide production as assessed with DHE staining and SOD activity. Western blots showed that Arf negatively regulates the phosphorylation of Akt. Luciferase assay in Hela cells additionally suggested that Arf negatively regulates Il6 transcriptional activity through a PI3 K/Akt mediated pathway. These findings strongly suggest that the enhanced Arf expression in oxidative stress plays compensatory protective roles against aging-related dysregulation of gene expression in adipocytes.


Subject(s)
Adipocytes/metabolism , Aging/metabolism , Cellular Senescence/physiology , Cyclin-Dependent Kinase Inhibitor p16/metabolism , Gene Expression Regulation, Developmental/physiology , Reactive Oxygen Species/metabolism , 3T3-L1 Cells , Animals , HeLa Cells , Humans , Mice , Up-Regulation/physiology
16.
Environ Urban ; 27(1): 217-230, 2015 Apr.
Article in English | MEDLINE | ID: mdl-26321797

ABSTRACT

Karachi is one of the world's fastest growing large cities. This paper describes the complex processes by which land is (formally and informally) made available for housing (and for commercial development), as well as who benefits - and how the low-income majority of Karachi citizens lose out. It also describes what underpins this - especially the political complications in a city that has grown so rapidly, has had fundamental changes in its ethnic composition (and thus also in its politics) and has attracted so many illegal immigrants. The paper describes the changes in formal and informal land markets over the last 50 years and the changing responses by government agencies to housing (and land for housing) issues. Also explored are the connections among land, housing and transport (which include different processes of densification) and the complex politics involved. The paper ends with recommendations for land titling, for changes in transport policies, for better use of land already owned by government agencies, for cross-political party agreement on how to address serious security issues (that are leading to loss of investment) and for increased political effectiveness of Karachi's active civil society organizations.

17.
Mol Cell Endocrinol ; 406: 10-8, 2015 May 05.
Article in English | MEDLINE | ID: mdl-25697344

ABSTRACT

Vascular endothelial growth factor-A (VEGF-A) released from adipocytes promotes angiogenesis; and thereby ameliorates the local hypoxia-induced adipose inflammation and insulin resistance. Here, we newly found that eicosapentaenoic acid (EPA) upregulated both mRNA expression and release of VEGF-A in mature 3T3-L1 adipocytes. Silencing mRNA of G-protein coupled receptor 120 (GPR120) and specific inhibition of peroxisome proliferator-activated receptor γ (PPARγ) by GW9662 respectively attenuated the EPA-induced augmentation of VEGF-A release by adipocytes. Furthermore, transfection of GPR120 gene alone and PPARγ gene alone to HEK293 cells respectively increased the promoter activity of VEGF-A as assessed by luciferase reporter assay, which was further augmented when both genes were co-transfected. Promoter deletion analysis and chromatin immunoprecipitation assay revealed that co-transfection of GPR120 enhanced EPA-induced PPARγ binding to PPAR-response element in VEGF-A promoter region. Thus, by the synchronized activation of a membrane receptor GRP120 and a nuclear receptor PPARγ, EPA enhances VEGF-A production in adipocytes.


Subject(s)
Adipocytes/metabolism , Eicosapentaenoic Acid/pharmacology , PPAR gamma/metabolism , Receptors, G-Protein-Coupled/metabolism , Signal Transduction/drug effects , Up-Regulation/drug effects , Vascular Endothelial Growth Factor A/genetics , 3T3-L1 Cells , Adipocytes/drug effects , Animals , HEK293 Cells , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Mice , Models, Biological , Phosphatidylinositol 3-Kinases/metabolism , Protein Binding/drug effects , Protein Kinase C/metabolism , Response Elements/genetics , Vascular Endothelial Growth Factor A/metabolism
18.
Hypertens Res ; 37(7): 621-8, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24599011

ABSTRACT

Angiotensin (Ang) II receptor blockers (ARBs) alleviate obesity-related insulin resistance, which suggests an important role for the Ang II type 1 receptor (AT1R) in the regulation of adipocytokines. Therefore, we treated mature 3T3-L1 adipocytes with 50 µmol l(-1) of valsartan, a selective AT1R blocker without direct agonism to peroxisome proliferator-activated receptor (PPAR)-γ. In the absence of effective concentrations of Ang II, unstimulated mature adipocytes expressed and secreted high levels of interleukin (IL)-6. This constitutive proinflammatory activity was attenuated by the suppression of extracellular signal-regulated kinase phosphorylation by valsartan but was unaffected by the Ang II type 2 receptor blocker PD123319. COS7 cells co-transfected with AT1R and IL-6, which expressed NF-κB but lacked PPAR-γ, showed no constitutive but substantial ligand-dependent IL-6 reporter activity, which was counteracted by valsartan. Valsartan preserved cytosolic IκB-α and subsequently reduced nuclear NF-κB1 protein expression in mature adipocytes. Interestingly, valsartan did not increase PPAR-γ messenger RNA expression per se but enhanced the transcriptional activity of PPAR-γ in mature adipocytes; this enhancement was accompanied by upregulation of the PPAR coactivator (PGC)-1α. Moreover, T0090907, a PPAR-γ inhibitor, increased IL-6 expression, and this increase was attenuated by valsartan. Indeed, addition of valsartan without direct PPAR-γ agonism increased adiponectin production in mature adipocytes. Together, the findings indicate that valsartan blocks the constitutive AT1R activity involving the NF-κB pathway that limits PPAR-γ activity in mature adipocytes. Thus, inverse agonism of AT1R attenuates the spontaneous proinflammatory response and enhances the constitutive insulin-sensitizing activities of mature adipocytes, which may underlie the beneficial metabolic impacts of ARBs.


Subject(s)
Adipocytes/drug effects , Adipokines/genetics , Angiotensin II Type 1 Receptor Blockers/pharmacology , Drug Inverse Agonism , Obesity/metabolism , Receptor, Angiotensin, Type 1/physiology , Tetrazoles/pharmacology , Valine/analogs & derivatives , 3T3-L1 Cells , Active Transport, Cell Nucleus , Adipocytes/metabolism , Angiotensin II/pharmacology , Animals , COS Cells , Chlorocebus aethiops , Interleukin-6/genetics , Mice , NF-kappa B/metabolism , PPAR gamma/physiology , Valine/pharmacology , Valsartan
19.
PLoS One ; 8(11): e79724, 2013.
Article in English | MEDLINE | ID: mdl-24223187

ABSTRACT

The steroid receptor antagonist mifepristone is used as an anti-cancer agent, eliciting both cytostatic and cytotoxic effects on malignant cells. However, the metabolic effects of long-term treatment with mifepristone have remained unclear. The effects of mifepristone on insulin sensitivity and adiponectin secretion were evaluated both in in vivo and in vitro. First, we explored the effects of mifepristone, on metabolic functions in obese mice receiving a high-fat diet. When these mice were fed mifepristone, they exhibited a marked improvement in insulin sensitivity, attenuated hepatic injury, and decreased adipocyte size, compared with mice that received only the high-fat diet. Intriguingly, mifepristone-treated mice showed significantly elevated plasma adiponectin levels. Second, we tested the effects of mifepristone on differentiated 3T3-L1 adipocytes in vitro. When differentiated adipocytes were treated with mifepristone for 48 h, adiponectin was upregulated at both mRNA and protein levels. Collectively, these results reveal novel actions of mifepristone on metabolic functions, in vivo and in vitro, in which the drug exerts antidiabetic effects associated with an upregulation in adiponectin-secretion.


Subject(s)
Adiponectin/biosynthesis , Diet, High-Fat/adverse effects , Insulin Resistance , Mifepristone/pharmacology , Obesity/drug therapy , Obesity/metabolism , 3T3-L1 Cells , Adipose Tissue/drug effects , Adipose Tissue/metabolism , Adipose Tissue/pathology , Animals , Cell Differentiation/drug effects , Disease Models, Animal , Male , Mice , Mifepristone/therapeutic use , Obesity/etiology , Obesity/pathology
20.
Biochem Biophys Res Commun ; 411(2): 375-80, 2011 Jul 29.
Article in English | MEDLINE | ID: mdl-21741366

ABSTRACT

Pioglitazone, a synthetic ligand of peroxisome proliferator-activated receptor (PPAR)γ, causes preadipocyte proliferation through a mechanism which still remains elusive. Here, to address the mechanism, we investigated the effects of PPARγ and pioglitazone on the kinetics of cyclin-dependent kinase inhibitors, especially with p16(Ink4a) (p16) centered, by employing 3T3-L1 preadipocytes. Pioglitazone promoted preadipocyte proliferation by increasing S and G(2)/M cell-cycle entry, which was accompanied by decreased p16 mRNA expression. PPARγ overexpression along with the luciferase reporter assay confirmed that PPARγ was crucial for the downregulation of p16 mRNA transcription, and that the action was augmented by pioglitazone. Thus, pioglitazone exerted cell-cycle dependent promoting effect on preadipocyte proliferation, of which mechanisms include p16-downregulation through PPARγ.


Subject(s)
Adipocytes/drug effects , Cell Proliferation/drug effects , Cyclin-Dependent Kinase Inhibitor p16/antagonists & inhibitors , Hypoglycemic Agents/pharmacology , Thiazolidinediones/pharmacology , 3T3-L1 Cells , Adipocytes/cytology , Animals , Cell Cycle/drug effects , Cyclin-Dependent Kinase Inhibitor p16/genetics , Down-Regulation , Mice , PPAR gamma/agonists , PPAR gamma/metabolism , Pioglitazone , RNA, Messenger/antagonists & inhibitors , RNA, Messenger/biosynthesis , Transcription, Genetic/drug effects
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