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1.
iScience ; 26(10): 107997, 2023 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-37810249

RESUMO

15-keto-PGE2 is one of the eicosanoids with anti-inflammatory properties. In this study, we demonstrated that 15-keto-PGE2 post-translationally modified the nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) subunits p105/p50 and p65 at Cys59 and Cys120 sites, respectively, hence inhibiting the activation of NF-κB signaling in macrophages. In mice fed a high-fat and high-sucrose diet (HFHSD), 15-keto-PGE2 treatment reduced pro-inflammatory cytokines and fasting glucose levels. In mice with non-alcoholic steatohepatitis (NASH) induced by a prolonged HFHSD, 15-keto-PGE2 treatment significantly decreased liver inflammation, lowered serum levels of alanine transaminase (ALT) and aspartate transferase (AST), and inhibited macrophage infiltration. It also reduced lipid droplet size and downregulated key regulators of lipogenesis. These findings highlight the potential of 15-keto-PGE2, through NF-κB modification, in preventing the development and progression of steatohepatitis, emphasizing the significance of endogenous lipid mediators in the inflammatory response.

2.
Am J Nephrol ; 54(9-10): 359-369, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37437553

RESUMO

INTRODUCTION: Chronic kidney disease, which is defined by a reduced estimated glomerular filtration rate and albuminuria, imposes a large health burden worldwide. Ethnicity-specific associations are frequently observed in genome-wide association studies (GWAS). This study conducts a GWAS of albuminuria in the nondiabetic population of Taiwan. METHODS: Nondiabetic individuals aged 30-70 years without a history of cancer were enrolled from the Taiwan Biobank. A total of 6,768 subjects were subjected to a spot urine examination. After quality control using PLINK and imputation using SHAPEIT and IMPUTE2, a total of 3,638,350 single-nucleotide polymorphisms (SNPs) remained for testing. SNPs with a minor allele frequency of less than 0.1% were excluded. Linear regression was used to determine the relationship between SNPs and log urine albumin-to-creatinine ratio. RESULTS: Six suggestive loci are identified in or near the FCRL3 (p = 2.56 × 10-6), TMEM161 (p = 4.43 × 10-6), EFCAB1 (p = 2.03 × 10-6), ELMOD1 (p = 2.97 × 10-6), RYR3 (p = 1.34 × 10-6), and PIEZO2 (p = 2.19 × 10-7). Genetic variants in the FCRL3 gene that encode a secretory IgA receptor are found to be associated with IgA nephropathy, which can manifest as proteinuria. The PIEZO2 gene encodes a sensor for mechanical forces in mesangial cells and renin-producing cells. Five SNPs with a p-value between 5 × 10-6 and 5 × 10-5 are also identified in five genes that may have a biological role in the development of albuminuria. CONCLUSION: Five new loci and one known suggestive locus for albuminuria are identified in the nondiabetic Taiwanese population.


Assuntos
Glomerulonefrite por IGA , Insuficiência Renal Crônica , Humanos , Estudo de Associação Genômica Ampla , Albuminúria/genética , Albuminúria/epidemiologia , Testes de Função Renal , Polimorfismo de Nucleotídeo Único
3.
Life (Basel) ; 13(4)2023 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-37109553

RESUMO

Diabetic patients have a two- to four-fold increase in the risk of heart failure (HF), and the co-existence of diabetes and HF is associated with poor prognosis. In randomized clinical trials (RCTs), compelling evidence has demonstrated the beneficial effects of sodium-glucose co-transporter-2 inhibitors on HF. The mechanism includes increased glucosuria, restored tubular glomerular feedback with attenuated renin-angiotensin II-aldosterone activation, improved energy utilization, decreased sympathetic tone, improved mitochondria calcium homeostasis, enhanced autophagy, and reduced cardiac inflammation, oxidative stress, and fibrosis. The RCTs demonstrated a neutral effect of the glucagon-like peptide receptor agonist on HF despite its weight-reducing effect, probably due to it possibly increasing the heart rate via increasing cyclic adenosine monophosphate (cAMP). Observational studies supported the markedly beneficial effects of bariatric and metabolic surgery on HF despite no current supporting evidence from RCTs. Bromocriptine can be used to treat peripartum cardiomyopathy by reducing the harmful cleaved prolactin fragments during late pregnancy. Preclinical studies suggest the possible beneficial effect of imeglimin on HF through improving mitochondrial function, but further clinical evidence is needed. Although abundant preclinical and observational studies support the beneficial effects of metformin on HF, there is limited evidence from RCTs. Thiazolidinediones increase the risk of hospitalized HF through increasing renal tubular sodium reabsorption mediated via both the genomic and non-genomic action of PPARγ. RCTs suggest that dipeptidyl peptidase-4 inhibitors, including saxagliptin and possibly alogliptin, may increase the risk of hospitalized HF, probably owing to increased circulating vasoactive peptides, which impair endothelial function, activate sympathetic tones, and cause cardiac remodeling. Observational studies and RCTs have demonstrated the neutral effects of insulin, sulfonylureas, an alpha-glucosidase inhibitor, and lifestyle interventions on HF in diabetic patients.

4.
Biomedicines ; 11(3)2023 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-36979641

RESUMO

Diabetic cardiomyopathy is characterized by abnormal myocardial structure or performance in the absence of coronary artery disease or significant valvular heart disease in patients with diabetes mellitus. The spectrum of diabetic cardiomyopathy ranges from subtle myocardial changes to myocardial fibrosis and diastolic function and finally to symptomatic heart failure. Except for sodium-glucose transport protein 2 inhibitors and possibly bariatric and metabolic surgery, there is currently no specific treatment for this distinct disease entity in patients with diabetes. The molecular mechanism of diabetic cardiomyopathy includes impaired nutrient-sensing signaling, dysregulated autophagy, impaired mitochondrial energetics, altered fuel utilization, oxidative stress and lipid peroxidation, advanced glycation end-products, inflammation, impaired calcium homeostasis, abnormal endothelial function and nitric oxide production, aberrant epidermal growth factor receptor signaling, the activation of the renin-angiotensin-aldosterone system and sympathetic hyperactivity, and extracellular matrix accumulation and fibrosis. Here, we summarize several important emerging treatments for diabetic cardiomyopathy targeting specific molecular mechanisms, with evidence from preclinical studies and clinical trials.

5.
J Biomed Sci ; 30(1): 13, 2023 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-36803854

RESUMO

BACKGROUND: Genome-wide association studies (GWASs) have linked RRBP1 (ribosomal-binding protein 1) genetic variants to atherosclerotic cardiovascular diseases and serum lipoprotein levels. However, how RRBP1 regulates blood pressure is unknown. METHODS: To identify genetic variants associated with blood pressure, we performed a genome-wide linkage analysis with regional fine mapping in the Stanford Asia-Pacific Program for Hypertension and Insulin Resistance (SAPPHIRe) cohort. We further investigated the role of the RRBP1 gene using a transgenic mouse model and a human cell model. RESULTS: In the SAPPHIRe cohort, we discovered that genetic variants of the RRBP1 gene were associated with blood pressure variation, which was confirmed by other GWASs for blood pressure. Rrbp1- knockout (KO) mice had lower blood pressure and were more likely to die suddenly from severe hyperkalemia caused by phenotypically hyporeninemic hypoaldosteronism than wild-type controls. The survival of Rrbp1-KO mice significantly decreased under high potassium intake due to lethal hyperkalemia-induced arrhythmia and persistent hypoaldosteronism, which could be rescued by fludrocortisone. An immunohistochemical study revealed renin accumulation in the juxtaglomerular cells of Rrbp1-KO mice. In the RRBP1-knockdown Calu-6 cells, a human renin-producing cell line, transmission electron and confocal microscopy revealed that renin was primarily retained in the endoplasmic reticulum and was unable to efficiently target the Golgi apparatus for secretion. CONCLUSIONS: RRBP1 deficiency in mice caused hyporeninemic hypoaldosteronism, resulting in lower blood pressure, severe hyperkalemia, and sudden cardiac death. In juxtaglomerular cells, deficiency of RRBP1 reduced renin intracellular trafficking from ER to Golgi apparatus. RRBP1 is a brand-new regulator of blood pressure and potassium homeostasis discovered in this study.


Assuntos
Proteínas de Transporte , Hiperpotassemia , Hipertensão , Hipoaldosteronismo , Animais , Humanos , Camundongos , Aldosterona , Óxido de Alumínio , Pressão Sanguínea , Estudo de Associação Genômica Ampla , Homeostase , Hiperpotassemia/complicações , Hipoaldosteronismo/complicações , Potássio , Renina/genética , Proteínas de Transporte/genética , Proteínas de Transporte/fisiologia
6.
Biomolecules ; 11(10)2021 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-34680107

RESUMO

Chronic hyperglycemia and hyperlipidemia hamper beta cell function, leading to glucolipotoxicity. Mitochondrial aldehyde dehydrogenase 2 (ALDH2) detoxifies reactive aldehydes, such as methylglyoxal (MG) and 4-hydroxynonenal (4-HNE), derived from glucose and lipids, respectively. We aimed to investigate whether ALDH2 activators ameliorated beta cell dysfunction and apoptosis induced by glucolipotoxicity, and its potential mechanisms of action. Glucose-stimulated insulin secretion (GSIS) in MIN6 cells and insulin secretion from isolated islets in perifusion experiments were measured. The intracellular ATP concentrations and oxygen consumption rates of MIN6 cells were assessed. Furthermore, the cell viability, apoptosis, and mitochondrial and intracellular reactive oxygen species (ROS) levels were determined. Additionally, the pro-apoptotic, apoptotic, and anti-apoptotic signaling pathways were investigated. We found that Alda-1 enhanced GSIS by improving the mitochondrial function of pancreatic beta cells. Alda-1 rescued MIN6 cells from MG- and 4-HNE-induced beta cell death, apoptosis, mitochondrial dysfunction, and ROS production. However, the above effects of Alda-1 were abolished in Aldh2 knockdown MIN6 cells. In conclusion, we reported that the activator of ALDH2 not only enhanced GSIS, but also ameliorated the glucolipotoxicity of beta cells by reducing both the mitochondrial and intracellular ROS levels, thereby improving mitochondrial function, restoring beta cell function, and protecting beta cells from apoptosis and death.


Assuntos
Aldeído-Desidrogenase Mitocondrial/genética , Células Secretoras de Insulina/metabolismo , Mitocôndrias/genética , Estresse Oxidativo/efeitos dos fármacos , Trifosfato de Adenosina/genética , Aldeídos/farmacologia , Animais , Apoptose/efeitos dos fármacos , Benzamidas/farmacologia , Benzodioxóis/farmacologia , Morte Celular/efeitos dos fármacos , Modelos Animais de Doenças , Glucose/metabolismo , Humanos , Secreção de Insulina/genética , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/patologia , Lipídeos/genética , Desintoxicação Metabólica Fase I/genética , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Espécies Reativas de Oxigênio/metabolismo
7.
Antioxidants (Basel) ; 10(3)2021 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-33805825

RESUMO

Diabetes mellitus has reached epidemic proportion worldwide. One of the diabetic complications is cardiomyopathy, characterized by early left ventricular (LV) diastolic dysfunction, followed by development of systolic dysfunction and ventricular dilation at a late stage. The pathogenesis is multifactorial, and there is no effective treatment yet. In recent years, 4-hydroxy-2-nonenal (4-HNE), a toxic aldehyde generated from lipid peroxidation, is implicated in the pathogenesis of cardiovascular diseases. Its high bioreactivity toward proteins results in cellular damage. Mitochondrial aldehyde dehydrogenase 2 (ALDH2) is the major enzyme that detoxifies 4-HNE. The development of small-molecule ALDH2 activator provides an opportunity for treating diabetic cardiomyopathy. This study found that AD-9308, a water-soluble andhighly selective ALDH2 activator, can improve LV diastolic and systolic functions, and wall remodeling in streptozotocin-induced diabetic mice. AD-9308 treatment dose-dependently lowered serum 4-HNE levels and 4-HNE protein adducts in cardiac tissue from diabetic mice, accompanied with ameliorated myocardial fibrosis, inflammation, and apoptosis. Improvements of mitochondrial functions, sarco/endoplasmic reticulumcalcium handling and autophagy regulation were also observed in diabetic mice with AD-9308 treatment. In conclusion, ADLH2 activation effectively ameliorated diabetic cardiomyopathy, which may be mediated through detoxification of 4-HNE. Our findings highlighted the therapeutic potential of ALDH2 activation for treating diabetic cardiomyopathy.

8.
J Diabetes Investig ; 12(6): 909-913, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33686797

RESUMO

Metformin improves mitochondrial function and enhances autophagy of T helper 17 cells, leading to decreased inflammation. This highlights the importance of metabolic modulation of immune cells.


Assuntos
Envelhecimento/imunologia , Diabetes Mellitus Tipo 2/imunologia , Resistência à Insulina/imunologia , Células Th17/imunologia , Animais , Humanos , Hipoglicemiantes/farmacologia , Metformina/farmacologia , Camundongos , Células Th17/efeitos dos fármacos
9.
J Diabetes Investig ; 9(5): 1067-1074, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29364582

RESUMO

AIMS/INTRODUCTION: Vascular adhesion protein-1 (VAP-1) is a membrane-bound amine oxidase highly expressed in mature adipocytes and released into the circulation. VAP-1 has been strongly implicated in several pathological processes, including diabetes, inflammation, hypertension, hepatic steatosis and renal diseases, and is an important disease marker and therapeutic target. Here, we aimed to identify the genetic loci for circulating VAP-1 levels. MATERIALS AND METHODS: We carried out a genomic-wide linkage scan for the quantitative trait locus of circulating VAP-1 levels in 1,100 Han Chinese individuals from 398 families in the Stanford Asian Pacific Program for Hypertension and Insulin Resistance study. Regional association fine mapping was carried out using additional single-nucleotide polymorphisms. RESULTS: The estimated heritability of circulating VAP-1 levels is high (h2 = 69%). The most significant quantitative trait locus for circulating VAP-1 was located at 38 cM on chromosome 20, with a maximum empirical logarithm of odds score of 4.11 (P = 6.86 × 10-6 ) in females. Regional single-nucleotide polymorphism fine mapping within a 1-unit support region showed the strongest association signals in the MACRO domain containing 2 (MACROD2) gene in females (P = 5.38 × 10-6 ). Knockdown of MACROD2 significantly suppressed VAP-1 expression in human adipocytes, as well as the expression of key adipogenic genes. Furthermore, MACROD2 expression was found to be positively associated with VAP-1 in human visceral adipose tissue. CONCLUSION: MACROD2 is a potential genetic determinant of serum VAP-1 levels, probably through transcriptional regulation of adipogenesis.


Assuntos
Adipogenia/genética , Amina Oxidase (contendo Cobre)/genética , Biomarcadores/metabolismo , Moléculas de Adesão Celular/genética , Enzimas Reparadoras do DNA/genética , Regulação da Expressão Gênica , Ligação Genética , Hidrolases/genética , Feminino , Seguimentos , Humanos , Resistência à Insulina , Masculino , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas , Taiwan
10.
Free Radic Biol Med ; 115: 113-126, 2018 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-29175486

RESUMO

Sepsis is a systemic inflammation accompanied by multi-organ dysfunction due to microbial infection. Prostaglandins and their metabolites have long been studied for their importance in regulating the innate immune response. 15-keto-PGE2 (15k-PGE2) is a prostaglandin E2 (PGE2) metabolite, whose further processing is catalyzed by prostaglandin reductase 2 (PTGR2). We showed disruption of the Ptgr2 gene in mice improves the survival rate under both LPS- and cecum ligation/puncture (CLP)-induced experimental sepsis. Knockdown of PTGR2 showed significant accumulation of intracellular 15k-PGE2 in activated macrophages. Both PTGR2 knockdown and exogenous treatment with 15k-PGE2 resulted in reduced pro-inflammatory cytokines production in LPS-stimulated RAW264.7 cells or bone marrow-derived macrophages (BMDM). The same treatment in RAW264.7 and BMDM also led to increased levels of the anti-oxidative transcription factor, Nuclear factor (erythroid-2) related factor-2 (NRF2), augmented anti-oxidant response element (ARE)-mediated reporter activity and upregulated expression of the corresponding anti-oxidant genes. 15k-PGE2 further demonstrated modification to Kelch-like ECH-associated protein 1 (Keap1), a negative regulator of Nrf2, at cysteine 288 (Cys288) site post-translationally. Finally, 15k-PGE2-treated mice were found to be more resistant to experimental sepsis. Taken together, our study affirms the significance of PTGR2 and 15k-PGE2 in mitigating inflammatory responses and suggests a novel anti-oxidative and anti-inflammatory therapy for sepsis through targeting PTGR2 and administering15k-PGE2.


Assuntos
15-Oxoprostaglandina 13-Redutase/metabolismo , Álcool Desidrogenase/metabolismo , Dinoprostona/análogos & derivados , Inflamação/imunologia , Macrófagos/imunologia , Sepse/metabolismo , Álcool Desidrogenase/genética , Animais , Dinoprostona/metabolismo , Modelos Animais de Doenças , Células HEK293 , Humanos , Imunidade Inata , Proteína 1 Associada a ECH Semelhante a Kelch/metabolismo , Lipopolissacarídeos/imunologia , Camundongos , Camundongos Knockout , Terapia de Alvo Molecular , Células RAW 264.7 , Espécies Reativas de Oxigênio , Transdução de Sinais
11.
PLoS One ; 11(1): e0147390, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26820738

RESUMO

Prostaglandin reductase 2 (PTGR2) is the enzyme that catalyzes 15-keto-PGE2, an endogenous PPARγ ligand, into 13,14-dihydro-15-keto-PGE2. Previously, we have reported a novel oncogenic role of PTGR2 in gastric cancer, where PTGR2 was discovered to modulate ROS-mediated cell death and tumor transformation. In the present study, we demonstrated the oncogenic potency of PTGR2 in pancreatic cancer. First, we observed that the majority of the human pancreatic ductal adenocarcinoma tissues was stained positive for PTGR2 expression but not in the adjacent normal parts. In vitro analyses showed that silencing of PTGR2 expression enhanced ROS production, suppressed pancreatic cell proliferation, and promoted cell death through increasing 15-keto-PGE2. Mechanistically, silencing of PTGR2 or addition of 15-keto-PGE2 suppressed the expressions of solute carrier family 7 member 11 (xCT) and cystathionine gamma-lyase (CTH), two important providers of intracellular cysteine for the generation of glutathione (GSH), which is widely accepted as the first-line antioxidative defense. The oxidative stress-mediated cell death after silencing of PTGR2 or addition of 15-keto-PGE2 was further abolished after restoring intracellular GSH concentrations and cysteine supply by N-acetyl-L-cysteine and 2-Mercaptomethanol. Our data highlight the therapeutic potential of targeting PTGR2/15-keto-PGE2 for pancreatic cancer.


Assuntos
Álcool Desidrogenase/genética , Carcinoma Ductal Pancreático/enzimologia , Dinoprostona/análogos & derivados , Estresse Oxidativo , Neoplasias Pancreáticas/enzimologia , 15-Oxoprostaglandina 13-Redutase , Álcool Desidrogenase/metabolismo , Sistema y+ de Transporte de Aminoácidos/genética , Sistema y+ de Transporte de Aminoácidos/metabolismo , Apoptose , Linhagem Celular Tumoral , Proliferação de Células , Sobrevivência Celular , Cistationina gama-Liase/genética , Cistationina gama-Liase/metabolismo , Dinoprostona/fisiologia , Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Glutationa/metabolismo , Humanos , PPAR gama/metabolismo , Espécies Reativas de Oxigênio/metabolismo
12.
Anal Cell Pathol (Amst) ; 2015: 972891, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26613076

RESUMO

The type 2 diabetes pandemic in recent decades is a huge global health threat. This pandemic is primarily attributed to the surplus of nutrients and the increased prevalence of obesity worldwide. In contrast, calorie restriction and weight reduction can drastically prevent type 2 diabetes, indicating a central role of nutrient excess in the development of diabetes. Recently, the molecular links between excessive nutrients, organelle stress, and development of metabolic disease have been extensively studied. Specifically, excessive nutrients trigger endoplasmic reticulum stress and increase the production of mitochondrial reactive oxygen species, leading to activation of stress signaling pathway, inflammatory response, lipogenesis, and pancreatic beta-cell death. Autophagy is required for clearance of hepatic lipid clearance, alleviation of pancreatic beta-cell stress, and white adipocyte differentiation. ROS scavengers, chemical chaperones, and autophagy activators have demonstrated promising effects for the treatment of insulin resistance and diabetes in preclinical models. Further results from clinical trials are eagerly awaited.


Assuntos
Diabetes Mellitus Tipo 2/patologia , Obesidade/patologia , Organelas/patologia , Estresse Fisiológico , Animais , Autofagia , Humanos , Mitocôndrias/patologia
13.
Endocrinology ; 154(3): 1117-29, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23389954

RESUMO

Adiponectin is an important adipose-specific protein, which possesses insulin (INS)-sensitizing, antiinflammatory, and antiatherosclerotic functions. However, its regulation remains largely unknown. In this study, we identified that ryanodine receptor (RyR)3 plays an important role in the regulation of adiponectin expression. RyR3 was expressed in 3T3-L1 preadipocytes, and its level was decreased upon adipogenesis. Silencing of RyR3 expression in 3T3-L1 preadipocytes resulted in up-regulated adiponectin promoter activity, enhanced adiponectin mRNA expression, and more adiponectin protein secreted into the medium. An inverse relation between RyR3 and adiponectin mRNA levels was also observed in adipose tissues of db/db mice. In addition, knockdown of RyR3 with small interfering RNA (siRNA) in db/db mice and high-fat diet-fed obese mice increased serum adiponectin level, improved INS sensitivity, and lowered fasting glucose levels. These effects were in parallel with decreased mitochondrial Ca(2+), increased mitochondrial mass, and reduced activating transcription factor 3 (atf3) expression. Overexpression of atf3 in 3T3-L1 preadipocytes blocked the effect of RyR3 silencing on adiponectin expression, indicating that an atf3-dependent pathway mediates the effect downstream of RyR3 silencing. Our data suggest that RyR3 may be a new therapeutic target for improving INS sensitivity and related metabolic disorders.


Assuntos
Fator 3 Ativador da Transcrição/genética , Adiponectina/genética , Canal de Liberação de Cálcio do Receptor de Rianodina/deficiência , Canal de Liberação de Cálcio do Receptor de Rianodina/genética , Células 3T3-L1 , Adipócitos/metabolismo , Adipogenia/genética , Animais , Sequência de Bases , Expressão Gênica , Técnicas de Silenciamento de Genes , Resistência à Insulina , Masculino , Camundongos , Camundongos Endogâmicos C3H , Camundongos Obesos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/genética , Transdução de Sinais
14.
J Cell Biochem ; 114(7): 1559-67, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23297177

RESUMO

Peroxisome proliferators-activated receptor gamma (PPARγ) receptor is a transcription factor that is located in and functions primarily in the nucleus. PPARγ is exported from the nucleus upon mitogen and ligand stimulation under certain circumstances. However, a cytoplasmic PPARγ interacting protein and its function have not been previously identified. Here, we report for the first time that cytosolic PPARγ interacts directly with cytoskeletal vimentin. We performed PPARγ immunoprecipitation followed by mass spectrometry to identify the vimentin-PPARγ complex. This interaction was confirmed by reciprocal vimentin and PPARγ immunoprecipitation and co-immunofluorescence examination. We demonstrated that PPARγ colocalized with vimentin in certain organelles that is golgi, mitochondria, and endoplasmic reticulum. In cells depleted of vimentin, PPARγ was ubiquitinated and targeted to a proteasomal degradation pathway. Together, these findings indicate a direct interaction of PPARγ with vimentin in the cytosolic compartment, in which vimentin appears to play a role in regulating the turnover rate of PPARγ, which may further regulate genomic or non-genomic activities through the regulation of PPARγ protein degradation.


Assuntos
PPAR gama/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Vimentina/metabolismo , Células 3T3-L1 , Animais , Western Blotting , Biologia Computacional , Imunoprecipitação , Espectrometria de Massas , Camundongos , Microscopia de Fluorescência , Ligação Proteica
15.
PLoS One ; 8(1): e51459, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23326314

RESUMO

BACKGROUND: 3T3-L1 cells are widely used to study adipogenesis and insulin response. Their adipogenic potential decreases with time in the culture. Expressing exogenous genes in 3T3-L1 cells can be challenging. This work tries to establish and characterize an alternative model of cultured adipocytes that is easier to work with than the 3T3-L1 cells. METHODOLOGY/PRINCIPAL FINDINGS: INDUCED CELLS WERE IDENTIFIED AS ADIPOCYTES BASED ON THE FOLLOWING THREE CHARACTERISTICS: (1) Accumulation of triglyceride droplets as demonstrated by oil red O stain. (2) Transport rate of 2-deoxyglucose increased after insulin stimulation. (3) Expression of fat specific genes such as Fabp4 (aP2), Slc2a4 (Glut4) and Pparg (PPARγ). Among the cell lines induced under different conditions in this study, only NIH/3T3 cells differentiated into adipocytes after prolonged incubation in 3T3-L1 induction medium containing 20% instead of 10% fetal bovine serum. Rosiglitazone added to the induction medium shortened the incubation period from 14 to 7 days. The PI3K/AKT pathway showed similar changes upon insulin stimulation in these two adipocytes. C/EBPα mRNA was barely detectable in NIH/3T3 adipocytes. NIH/3T3 adipocytes induced in the presence of rosiglitazone showed higher 2-deoxyglucose transport rate after insulin stimulation, expressed less Agt (angiotensinogen) and more PPARγ. Knockdown of C/EBPα using shRNA blocked 3T3-L1 but not NIH/3T3 cell differentiation. Mouse adipose tissues from various anatomical locations showed comparable levels of C/EBPα mRNA. CONCLUSIONS/SIGNIFICANCE: NIH/3T3 cells were capable of differentiating into adipocytes without genetic engineering. They were an adipocyte model that did not require the reciprocal activation between C/EBPα and PPARγ to differentiate. Future studies in the C/EBPα independent pathways leading to insulin responsiveness may reveal new targets to diabetes treatment.


Assuntos
Adipócitos/efeitos dos fármacos , Adipogenia/efeitos dos fármacos , Proteína alfa Estimuladora de Ligação a CCAAT/genética , Meios de Cultura/farmacologia , Células 3T3-L1 , Adipócitos/citologia , Adipócitos/metabolismo , Adipogenia/genética , Animais , Transporte Biológico/efeitos dos fármacos , Western Blotting , Proteína alfa Estimuladora de Ligação a CCAAT/metabolismo , Bovinos , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/genética , Meios de Cultura/química , Desoxiglucose/metabolismo , Proteínas de Ligação a Ácido Graxo/genética , Proteínas de Ligação a Ácido Graxo/metabolismo , Expressão Gênica/efeitos dos fármacos , Hipoglicemiantes/farmacologia , Insulina/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Células NIH 3T3 , PPAR gama/genética , PPAR gama/metabolismo , Interferência de RNA , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Rosiglitazona , Soro , Tiazolidinedionas/farmacologia , Fatores de Tempo , Triglicerídeos/metabolismo
16.
Am J Pathol ; 181(4): 1316-26, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22998775

RESUMO

Various prostanoids and peroxisome proliferator-activated receptor γ (PPARγ) ligands play an important role in gastric cancer. Previously, we demonstrated that prostaglandin reductase 2 (PTGR2) catalyzes the reduction of the PPARγ ligand 15-keto-PGE(2) into 13,14-dihydro-15-keto-PGE(2). Here, we present functional data and clinical relevance for the role of PTGR2 in gastric cancer. Using lentiviral technology in AGS and SNU-16 gastric cancer cell lines, we either down-regulated or overexpressed PTGR2. In vitro analysis showed that PTGR2 knockdown resulted in decreased proliferation rate and colony formation, and in vivo xenograft models showed slower growth of tumors. Mechanistically, PTGR2 knockdown induced cell death, altered mitochondrial function, and increased reactive oxygen species production, which led to activation of ERK1/2 and caspase 3, with increased Bcl-2 and suppressed Bax expression. PTGR2 overexpression showed the opposite outcomes. Clinically, immunopathological staining showed strong PTGR2 expression in the gastric tumor portion, relative to nearby nontumor portions, and its expression negatively correlated with survival of patients with intestinal-type gastric cancer. Finally, in contrast to PTGR2-overexpressing cells, PTGR2-knockdown cells were more sensitive to cisplatin and 5-fluorouracil. Taken together, our findings not only provide functional and mechanistic evidence of the involvement of PTGR2 in gastric cancer, but also provide clinical observations affirming the significance of PTGR2 in gastric cancer and suggesting that PTGR2-target based therapy is worth further evaluation.


Assuntos
Álcool Desidrogenase/metabolismo , Transformação Celular Neoplásica/patologia , Espécies Reativas de Oxigênio/metabolismo , Neoplasias Gástricas/mortalidade , Neoplasias Gástricas/patologia , 15-Oxoprostaglandina 13-Redutase , Animais , Caspase 3/metabolismo , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Transformação Celular Neoplásica/efeitos dos fármacos , Cisplatino/farmacologia , Cisplatino/uso terapêutico , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Feminino , Fluoruracila/farmacologia , Fluoruracila/uso terapêutico , Técnicas de Silenciamento de Genes , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Pessoa de Meia-Idade , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Modelos de Riscos Proporcionais , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Transdução de Sinais/efeitos dos fármacos , Neoplasias Gástricas/tratamento farmacológico , Neoplasias Gástricas/enzimologia , Análise de Sobrevida
17.
Obesity (Silver Spring) ; 20(8): 1558-65, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22331129

RESUMO

The deadenylase nocturnin (Noc, Ccrn4l) has been recently found to regulate lipid metabolism and to control preadipocyte differentiation. Here, we showed that among the five deadenylases tested, Noc and Pan2 exhibited a biphasic expression which is out of phase to each other during adipocyte differentiation of 3T3-L1 cells. The expression levels of other deadenylases, including Parn, Ccr4, and Caf1, were relatively unchanged or reduced. The immediate early expressed Noc during 3T3-L1 adipogenesis was involved in regulating mitotic clonal expansion (MCE) and cyclin D1 expression, as demonstrated in Noc-silenced 3T3-L1 cells and Noc(-/-) primary mouse embryonic fibroblasts (MEFs). Transcriptional profiling of Noc-depleted 3T3-L1 adipocytes revealed that most of the differentially expressed genes were related to cell growth and proliferation. In human adipose tissue, NOC mRNA level negatively associated with both fasting serum insulin and homeostasis model assessment of insulin resistance, and positively associated with both adiponectin mRNA levels and circulating adiponectin levels. Taken together, these results suggest the role of Noc in the modulation of early adipogenesis as well as systemic insulin sensitivity.


Assuntos
Adipogenia/fisiologia , Tecido Adiposo/metabolismo , Expressão Gênica , Resistência à Insulina , Mitose , Proteínas Nucleares/metabolismo , Obesidade/metabolismo , Fatores de Transcrição/metabolismo , Células 3T3-L1 , Adipogenia/genética , Adiponectina/sangue , Adiponectina/genética , Adiponectina/metabolismo , Tecido Adiposo/fisiologia , Adulto , Animais , Proliferação de Células , Ciclina D1/metabolismo , Jejum , Fibroblastos/metabolismo , Humanos , Insulina/sangue , Resistência à Insulina/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas Nucleares/genética , Obesidade/genética , RNA Mensageiro/metabolismo , Fatores de Transcrição/genética , Transcriptoma
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