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1.
Cell ; 147(3): 666-77, 2011 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-22036572

RESUMO

Synaptic transmission involves a fast synchronous phase and a slower asynchronous phase of neurotransmitter release that are regulated by distinct Ca(2+) sensors. Though the Ca(2+) sensor for rapid exocytosis, synaptotagmin I, has been studied in depth, the sensor for asynchronous release remains unknown. In a screen for neuronal Ca(2+) sensors that respond to changes in [Ca(2+)] with markedly slower kinetics than synaptotagmin I, we observed that Doc2--another Ca(2+), SNARE, and lipid-binding protein--operates on timescales consistent with asynchronous release. Moreover, up- and downregulation of Doc2 expression levels in hippocampal neurons increased or decreased, respectively, the slow phase of synaptic transmission. Synchronous release, when triggered by single action potentials, was unaffected by manipulation of Doc2 but was enhanced during repetitive stimulation in Doc2 knockdown neurons, potentially due to greater vesicle availability. In summary, we propose that Doc2 is a Ca(2+) sensor that is kinetically tuned to regulate asynchronous neurotransmitter release.


Assuntos
Proteínas de Ligação ao Cálcio/metabolismo , Cálcio/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Neurotransmissores/metabolismo , Transmissão Sináptica , Potenciais de Ação , Animais , Células Cultivadas , Técnicas de Silenciamento de Genes , Hipocampo/citologia , Hipocampo/metabolismo , Humanos , Metabolismo dos Lipídeos , Camundongos , Neurônios/metabolismo , Ratos , Proteínas SNARE/metabolismo , Vesículas Sinápticas/metabolismo , Sinaptotagmina I/genética , Sinaptotagmina I/metabolismo
2.
Retina ; 44(5): 820-830, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38194677

RESUMO

PURPOSE: To evaluate novice and senior vitreoretinal surgeons after various exposures. Multiple comparisons ranked the importance of these exposures for surgical dexterity based on experience. METHODS: This prospective cohort study included 15 novice and 11 senior vitreoretinal surgeons (<2 and >10 years' practice, respectively). Eyesi-simulator tasks were performed after each exposure. Day 1, placebo, 2.5 mg/kg caffeine, and 5.0 mg/kg caffeine; day 2, placebo, 0.2 mg/kg propranolol, and 0.6 mg/kg propranolol; day 3, baseline simulation, breathalyzer readings of 0.06% to 0.10% and 0.11% to 0.15% blood alcohol concentrations; day 4, baseline simulation, push-up sets with 50% and 85% repetitions maximum; and day 5, 3-hour sleep deprivation. Eyesi-generated score (0-700, worst-best), out-of-tolerance tremor (0-100, best-worst), task completion time (minutes), and intraocular pathway (in millimeters) were measured. RESULTS: Novice surgeons performed worse after caffeine (-29.53, 95% confidence interval [CI]: -57.80 to -1.27, P = 0.041) and alcohol (-51.33, 95% CI: -80.49 to -22.16, P = 0.001) consumption. Alcohol caused longer intraocular instrument movement pathways (212.84 mm, 95% CI: 34.03-391.65 mm, P = 0.02) and greater tremor (7.72, 95% CI: 0.74-14.70, P = 0.003) among novices. Sleep deprivation negatively affected novice performance time (2.57 minutes, 95% CI: 1.09-4.05 minutes, P = 0.001) and tremor (8.62, 95% CI: 0.80-16.45, P = 0.03); however, their speed increased after propranolol (-1.43 minutes, 95% CI: -2.71 to -0.15 minutes, P = 0.029). Senior surgeons' scores deteriorated only following alcohol consumption (-47.36, 95% CI: -80.37 to -14.36, P = 0.005). CONCLUSION: Alcohol compromised all participants despite their expertise level. Experience negated the effects of caffeine, propranolol, exercise, and sleep deprivation on surgical skills.


Assuntos
Competência Clínica , Destreza Motora , Oftalmologistas , Cirurgia Vitreorretiniana , Estudos Prospectivos , Estudos de Coortes , Simulação por Computador , Cafeína/efeitos adversos , Privação do Sono , Consumo de Bebidas Alcoólicas/efeitos adversos , Oftalmologistas/estatística & dados numéricos , Cirurgia Vitreorretiniana/estatística & dados numéricos , Destreza Motora/efeitos dos fármacos , Destreza Motora/fisiologia , Exposição Ambiental/efeitos adversos , Propranolol/efeitos adversos , Exercício Físico , Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade
3.
Mediators Inflamm ; 2023: 2364121, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37868614

RESUMO

Background: Inflammation is a major cause of hepatic tissue damage and accelerates the progression of nonalcoholic fatty liver disease (NAFLD). Amphiregulin (AREG), an epidermal growth factor receptor ligand, is associated with human liver cirrhosis and hepatocellular carcinoma. We aimed to investigate the effects of AREG on hepatic inflammation during NAFLD progression, in vivo and in vitro. Methods: AREG gene expression was measured in the liver of mice fed a methionine choline-deficient (MCD) diet for 2 weeks. We evaluated inflammatory mediators and signaling pathways in HepG2 cells after stimulation with AREG. Nitric oxide (NO), prostaglandin E2 (PGE2), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) were analyzed using an enzyme-linked immunosorbent assay and western blotting. Nuclear transcription factor kappa-B (NF-κB) and mitogen-activated protein kinases (MAPKs), including extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38 mitogen-activated protein kinase, were analyzed using western blotting. Results: Proinflammatory cytokines (interleukin (IL)-6, IL-1ß, and IL-8) and immune cell recruitment (as indicated by L3T4, F4/80, and ly6G mRNA expression) increased, and expression of AREG increased in the liver of mice fed the MCD diet. AREG significantly increased the expression of IL-6 and IL-1ß and the production of NO, PGE2, and IL-8 in HepG2 cells. It also activated the protein expression of iNOS and COX-2. AREG-activated NF-κB and MAPKs signaling, and together with NF-κB and MAPKs inhibitors, AREG significantly reduced the protein expression of iNOS and COX-2. Conclusion: AREG plays a role in hepatic inflammation by increasing iNOS and COX-2 expression via NF-κB and MAPKs signaling.


Assuntos
NF-kappa B , Hepatopatia Gordurosa não Alcoólica , Camundongos , Humanos , Animais , NF-kappa B/metabolismo , Ciclo-Oxigenase 2/metabolismo , Anfirregulina/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Dinoprostona , Interleucina-8/metabolismo , Inflamação/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Interleucina-6/metabolismo , Lipopolissacarídeos/farmacologia , Óxido Nítrico/metabolismo
4.
J Hepatol ; 77(3): 735-747, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35421426

RESUMO

BACKGROUND & AIMS: Mitochondrial dysfunction is considered a pathogenic linker in the development of non-alcoholic steatohepatitis (NASH). Inappropriate mitochondrial protein-quality control, possibly induced by insufficiency of the mitochondrial matrix caseinolytic protease P (ClpP), can potentially cause mitochondrial dysfunction. Herein, we aimed to investigate hepatic ClpP levels in a diet-induced model of NASH and determine whether supplementation of ClpP can ameliorate diet-induced NASH. METHODS: NASH was induced by a high-fat/high-fructose (HF/HFr) diet in C57BL/6J mice. Stress/inflammatory signals were induced in mouse primary hepatocytes (MPHs) by treatment with palmitate/oleate (PA/OA). ClpP levels in hepatocytes were reduced using the RNAi-mediated gene knockdown technique but increased through the viral transduction of ClpP. ClpP activation was induced by administering a chemical activator of ClpP. RESULTS: Hepatic ClpP protein levels in C57BL/6J mice fed a HF/HFr diet were lower than the levels in those fed a normal chow diet. PA/OA treatment also decreased the ClpP protein levels in MPHs. Overexpression or activation of ClpP reversed PA/OA-induced mitochondrial dysfunction and stress/inflammatory signal activation in MPHs, whereas ClpP knockdown induced mitochondrial dysfunction and stress/inflammatory signals in these cells. On the other hand, ClpP overexpression or activation improved HF/HFr-induced NASH characteristics such as hepatic steatosis, inflammation, fibrosis, and injury in the C57BL/6J mice, whereas ClpP knockdown further augmented steatohepatitis in mice fed a HF/HFr diet. CONCLUSIONS: Reduced ClpP expression and subsequent mitochondrial dysfunction are key to the development of diet-induced NASH. ClpP supplementation through viral transduction or chemical activation represents a potential therapeutic strategy to prevent diet-induced NASH. LAY SUMMARY: Western diets, containing high fat and high fructose, often induce non-alcoholic steatohepatitis (NASH). Mitochondrial dysfunction is considered pathogenically linked to diet-induced NASH. We observed that the mitochondrial protease ClpP decreased in the livers of mice fed a western diet and supplementation of ClpP ameliorated western diet-induced NASH.


Assuntos
Hepatopatia Gordurosa não Alcoólica , Animais , Dieta Hiperlipídica/efeitos adversos , Suplementos Nutricionais , Modelos Animais de Doenças , Endopeptidase Clp , Frutose/efeitos adversos , Frutose/metabolismo , Fígado/patologia , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias/metabolismo , Hepatopatia Gordurosa não Alcoólica/etiologia , Hepatopatia Gordurosa não Alcoólica/metabolismo , Hepatopatia Gordurosa não Alcoólica/prevenção & controle , Ácido Oleico/metabolismo , Peptídeo Hidrolases/metabolismo
5.
Biochem Biophys Res Commun ; 588: 154-160, 2022 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-34971904

RESUMO

Non-alcoholic fatty liver disease (NAFLD) includes a broad spectrum of liver diseases characterized by steatosis, inflammation, and fibrosis. This study aimed to investigate the potential of dipeptidyl peptidase-4 inhibitors and sodium-glucose cotransporter 2 inhibitors in alleviating the progression of NAFLD. The NAFLD model was generated by feeding male C57BL/6J mice a choline-deficient, L-amino acid-defined, high-fat diet (CDAHFD) for 7 weeks. After 2 weeks of CDAHFD feeding, the NAFLD model mice were assigned to four groups, namely (ⅰ) VEHICLE, (ⅱ) gemigliptin (GEMI), (ⅲ) empagliflozin (EMPA), and (ⅳ) GEMI + EMPA. For the next 5 weeks, mice received the vehicle or the drug based upon the group to which they belonged. Thereafter, the triglyceride concentration, extent of fibrosis, and the expression of genes encoding inflammatory cytokines, chemokines, and antioxidant enzymes were analyzed in the livers of mice. The NAFLD activity score and hepatic fibrosis grade were assessed via hematoxylin and eosin and Sirius Red staining of the liver tissue samples. All mice belonging to the GEMI, EMPA, and GEMI + EMPA groups showed improvements in the accumulation of liver triglycerides and the expression of inflammatory cytokines and chemokines. Additionally, the oxidative stress was reduced due to inhibition of the c-Jun N-terminal kinase pathway and upregulation of the antioxidant enzymes. Furthermore, in these three groups, the galectin-3 and interleukin 33-induced activity of tumor necrosis factor-α was inhibited, thereby preventing the progression of liver fibrosis. These findings suggest that the GEMI, EMPA, and GEMI + EMPA treatments ameliorate hepatic steatosis, inflammation, oxidative stress, and fibrosis in CDAHFD-induced NAFLD mouse models.


Assuntos
Compostos Benzidrílicos/uso terapêutico , Dieta Hiperlipídica , Glucosídeos/uso terapêutico , Fígado/patologia , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Piperidonas/farmacologia , Piperidonas/uso terapêutico , Substâncias Protetoras/uso terapêutico , Pirimidinas/farmacologia , Pirimidinas/uso terapêutico , Aminoácidos , Animais , Compostos Benzidrílicos/farmacologia , Colina , Citocinas/metabolismo , Modelos Animais de Doenças , Progressão da Doença , Glucosídeos/farmacologia , Inflamação/patologia , Mediadores da Inflamação/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Fígado/efeitos dos fármacos , Ativação de Macrófagos/efeitos dos fármacos , Masculino , Camundongos Endogâmicos C57BL , Estresse Oxidativo/efeitos dos fármacos , Fosforilação/efeitos dos fármacos , Substâncias Protetoras/farmacologia
6.
Int J Mol Sci ; 23(17)2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-36077368

RESUMO

The accumulation of hepatic lipid droplets (LDs) is a hallmark of non-alcoholic fatty liver disease (NAFLD). Appropriate degradation of hepatic LDs and oxidation of complete free fatty acids (FFAs) are important for preventing the development of NAFLD. Histone deacetylase (HDAC) is involved in the impaired lipid metabolism seen in high-fat diet (HFD)-induced obese mice. Here, we evaluated the effect of MS-275, an inhibitor of HDAC1/3, on the degradation of hepatic LDs and FFA oxidation in HFD-induced NAFLD mice. To assess the dynamic degradation of hepatic LDs and FFA oxidation in fatty livers of MS-275-treated HFD C57BL/6J mice, an intravital two-photon imaging system was used and biochemical analysis was performed. The MS-275 improved hepatic metabolic alterations in HFD-induced fatty liver by increasing the dynamic degradation of hepatic LDs and the interaction between LDs and lysozyme in the fatty liver. Numerous peri-droplet mitochondria, lipolysis, and lipophagy were observed in the MS-275-treated mouse fatty liver. Biochemical analysis revealed that the lipolysis and autophagy pathways were activated in MS-275 treated mouse liver. In addition, MS-275 reduced the de novo lipogenesis, but increased the mitochondrial oxidation and the expression levels of oxidation-related genes, such as PPARa, MCAD, CPT1b, and FGF21. Taken together, these results suggest that MS-275 stimulates the degradation of hepatic LDs and mitochondrial free fatty acid oxidation, thus protecting against HFD-induced NAFLD.


Assuntos
Hepatopatia Gordurosa não Alcoólica , Animais , Benzamidas , Dieta Hiperlipídica/efeitos adversos , Ácidos Graxos não Esterificados/metabolismo , Gotículas Lipídicas/metabolismo , Metabolismo dos Lipídeos , Fígado/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Obesos , Hepatopatia Gordurosa não Alcoólica/metabolismo , Piridinas
7.
J Gastroenterol Hepatol ; 36(9): 2592-2600, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33600604

RESUMO

BACKGROUND AND AIM: Non-alcoholic fatty liver disease (NAFLD) ranges from simple steatosis to non-alcoholic steatohepatitis, which is characterized by hepatic inflammation that can progress to fibrosis, cirrhosis, and hepatocellular carcinoma. Visfatin, an adipocytokine, was reported to induce pro-inflammatory cytokines and can be associated with liver fibrosis. We investigated the role of visfatin on hepatic inflammation and fibrosis in a methionine-choline-deficient (MCD)-diet-induced steatohepatitis mouse model. METHODS: Eight-week-old male C57BL/6 J mice were randomly assigned into one of three groups: (1) saline-injected control diet group; (2) saline-injected MCD diet group; and (3) visfatin-injected MCD diet group (n = 8 per group). Mice were administered intravenous saline or 10 µg/kg of recombinant murine visfatin for 2 weeks. Histologic assessment of liver and biochemical and molecular measurements of endoplasmic reticulum (ER) stress, reactive oxidative stress (ROS), inflammation, and fibrosis were performed in livers from these animals. RESULTS: Visfatin injection aggravated hepatic steatosis and increased plasma alanine aminotransferase and aspartate aminotransferase concentrations. Visfatin increased inflammatory cell infiltration (as indicated by F4/80, CD68, ly6G, and CD3 mRNA expression) and expression of chemokines in the liver. Visfatin also increased the expression of pro-inflammatory cytokines (IL-1ß, TNF-α, and IL-6) and activated fibrosis markers (CTGF, TIMP1, collagen 1α2, collagen 3α2, αSMA, fibronectin, and vimentin) in liver. Livers of visfatin-injected mice showed upregulation of ER stress and ROS and activation of JNK signaling. CONCLUSIONS: These results suggest that visfatin aggravates hepatic inflammation together with induction of ER and oxidative stress and exacerbates fibrosis in an MCD-diet-fed mouse model of NAFLD.


Assuntos
Adipocinas , Doença Hepática Induzida por Substâncias e Drogas , Dieta , Nicotinamida Fosforribosiltransferase , Hepatopatia Gordurosa não Alcoólica , Adipocinas/efeitos adversos , Animais , Doença Hepática Induzida por Substâncias e Drogas/etiologia , Doença Hepática Induzida por Substâncias e Drogas/imunologia , Doença Hepática Induzida por Substâncias e Drogas/patologia , Deficiência de Colina/complicações , Dieta/efeitos adversos , Modelos Animais de Doenças , Inflamação/induzido quimicamente , Inflamação/imunologia , Inflamação/patologia , Fígado/imunologia , Fígado/patologia , Cirrose Hepática/induzido quimicamente , Cirrose Hepática/imunologia , Cirrose Hepática/patologia , Masculino , Metionina/deficiência , Camundongos , Camundongos Endogâmicos C57BL , Nicotinamida Fosforribosiltransferase/efeitos adversos , Hepatopatia Gordurosa não Alcoólica/etiologia , Hepatopatia Gordurosa não Alcoólica/patologia
8.
J Neurosci ; 39(18): 3537-3550, 2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-30819799

RESUMO

The circadian clock organizes the physiology and behavior of organisms to their daily environmental rhythms. The central circadian timekeeping mechanism in eukaryotic cells is the transcriptional-translational feedback loop (TTFL). In the Drosophila TTFL, the transcription factors CLOCK (CLK) and CYCLE (CYC) play crucial roles in activating expression of core clock genes and clock-controlled genes. Many signaling pathways converge on the CLK/CYC complex and regulate its activity to fine-tune the cellular oscillator to environmental time cues. We aimed to identify factors that regulate CLK by performing tandem affinity purification combined with mass spectrometry using Drosophila S2 cells that stably express HA/FLAG-tagged CLK and V5-tagged CYC. We identified SNF4Aγ, a homolog of mammalian AMP-activated protein kinase γ (AMPKγ), as a factor that copurified with HA/FLAG-tagged CLK. The AMPK holoenzyme composed of a catalytic subunit AMPKα and two regulatory subunits, AMPKß and AMPKγ, directly phosphorylated purified CLK in vitro Locomotor behavior analysis in Drosophila revealed that knockdown of each AMPK subunit in pacemaker neurons induced arrhythmicity and long periods. Knockdown of AMPKß reduced CLK levels in pacemaker neurons, and thereby reduced pre-mRNA and protein levels of CLK downstream core clock genes, such as period and vrille Finally, overexpression of CLK reversed the long-period phenotype that resulted from AMPKß knockdown. Thus, we conclude that AMPK, a central regulator of cellular energy metabolism, regulates the Drosophila circadian clock by stabilizing CLK and activating CLK/CYC-dependent transcription.SIGNIFICANCE STATEMENT Regulation of the circadian transcription factors CLK and CYC is fundamental to synchronize the core clock with environmental changes. Here, we show that the AMPKγ subunit of AMPK, a central regulator of cellular metabolism, copurifies with the CLK/CYC complex in Drosophila S2 cells. Furthermore, the AMPK holoenzyme directly phosphorylates CLK in vitro This study demonstrates that AMPK activity regulates the core clock in Drosophila by activating CLK, which enhances circadian transcription. In mammals, AMPK affects the core clock by downregulating circadian repressor proteins. It is intriguing to note that AMPK activity is required for core clock regulation through circadian transcription enhancement, whereas the target of AMPK action is different in Drosophila and mammals (positive vs negative element, respectively).


Assuntos
Proteínas Quinases Ativadas por AMP/genética , Proteínas CLOCK/genética , Ritmo Circadiano/genética , Proteínas de Drosophila/genética , Regulação da Expressão Gênica , Animais , Regulação para Baixo , Drosophila melanogaster , Locomoção/genética , Masculino , Neurônios/metabolismo , Subunidades Proteicas/metabolismo
9.
Histopathology ; 76(7): 1032-1041, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31994201

RESUMO

AIMS: The classification of paediatric spindle mesenchymal tumours is evolving, and the spectrum of so-called 'infantile fibrosarcoma' has expanded to include tumours with NTRK, BRAF and MET gene fusions. RET-rearranged paediatric spindle cell neoplasms are an emerging group; there is sparse literature on their clinical, pathological and genetic features, and their nosological place in the canon of soft tissue tumours is uncertain. In this study, we report five RET-rearranged paediatric spindle cell tumours with fusion partners MYH10, KIAA1217 and CLIP2. METHODS AND RESULTS: The tumours occurred in the pelvic region, paraspinal region, kidney and subcutaneous tissue of hand and abdomen. The patients' ages ranged from 6 months to 13 years (median 1 year). The tumours were composed of monomorphic spindle cells arranged in a fascicular pattern. Lesional cells had minimally atypical ovoid or tapered nuclei and pale cytoplasm with indistinct borders. Necrosis was not identified. Mitoses numbered three to 12 per 10 high-power field. Cases showed inconsistent and variable expression of S100, CD34 and SMA. Clinical behaviour ranged from small lesions potentially cured by simple resection to large lesions exhibiting metastasis, but responsive to kinase inhibitor therapy. CONCLUSIONS: Our findings help to define RET-rearranged spindle cell tumours. Although it is likely that these tumours comprise part of the morphological and clinical spectrum of infantile fibrosarcoma (IFS), identification of RET gene alteration is important for its unique therapeutic implications.


Assuntos
Biomarcadores Tumorais/genética , Fibrossarcoma/genética , Proteínas Proto-Oncogênicas c-ret/genética , Neoplasias de Tecidos Moles/genética , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Fusão Oncogênica/genética , Proteínas de Fusão Oncogênica/genética
10.
Osteoporos Int ; 31(3): 547-555, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31720711

RESUMO

Thyroid dysfunction is associated with the loss of bone density (osteoporosis). However, the connection between subclinical thyroid dysfunction and osteoporosis remains controversial. This study found no apparent association between subclinical hypothyroidism or subclinical hyperthyroidism and bone mineral density (BMD) in the lumbar spine and femur. INTRODUCTION: The present study examined the relationship between subclinical thyroid dysfunction and BMD in healthy middle-aged adults. METHODS: A total of 25,510 healthy Koreans with normal free thyroxine levels were enrolled from January 2011 to December 2016, and 91% of subjects visited only once. The average age of the 15,761 women was 45, and the average age of the 9749 men was 48. Levels of thyroid-stimulating hormone (TSH) and BMD were recorded in all subjects. BMD was measured using dual-energy X-ray absorptiometry. RESULTS: No apparent association was found between subclinical thyroid dysfunction and BMD in the lumbar spine, femur-neck, and proximal femur sites compared with a euthyroid group. Age, body mass index (BMI), and postmenopausal status affected BMD in women, and only BMI affected BMD in men. Subclinical hypothyroidism was independently associated with a lower risk of osteoporosis (odds ratio 0.657, 95% confidence interval 0.464-0.930) in 4710 postmenopausal women. CONCLUSIONS: No apparent association was found between subclinical hypothyroidism or subclinical hyperthyroidism defined on single TSH measurement and BMD at the lumbar spine and femur in a large cohort of middle-aged men and women. Subclinical hypothyroidism was independently associated with a lower risk of osteoporosis in postmenopausal women.


Assuntos
Densidade Óssea , Osteoporose , Absorciometria de Fóton , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Osteoporose/epidemiologia , Osteoporose/etiologia , República da Coreia/epidemiologia
11.
FASEB J ; 33(2): 1771-1786, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30207798

RESUMO

Free fatty acid is considered to be one of the major pathogenic factors of inducing insulin resistance. The association between iron disturbances and insulin resistance has recently begun to receive a lot of attention. Although skeletal muscles are a major tissue for iron utilization and storage, the role of iron in palmitate (PA)-induced insulin resistance is unknown. We investigated the molecular mechanism underlying iron dysregulation in PA-induced insulin resistance. Interestingly, we found that PA simultaneously increased intracellular iron and induced insulin resistance. The iron chelator deferoxamine dramatically inhibited PA-induced insulin resistance, and iron donors impaired insulin sensitivity by activating JNK. PA up-regulated transferrin receptor 1 (tfR1), an iron uptake protein, which was modulated by iron-responsive element-binding proteins 2. Knockdown of tfR1 and iron-responsive element-binding proteins 2 prevented PA-induced iron uptake and insulin resistance. PA also translocated the tfR1 by stimulating calcium influx, but the calcium chelator, BAPTA-AM, dramatically reduced iron overload by inhibiting tfR1 translocation and ultimately increased insulin sensitivity. Iron overload may play a critical role in PA-induced insulin resistance. Blocking iron overload may thus be a useful strategy for preventing insulin resistance and diabetes.-Cui, R., Choi, S.-E., Kim, T. H., Lee, H. J., Lee, S. J., Kang, Y., Jeon, J. Y., Kim, H. J., Lee, K.-W. Iron overload by transferrin receptor protein 1 regulation plays an important role in palmitate-induced insulin resistance in human skeletal muscle cells.


Assuntos
Antígenos CD/metabolismo , Resistência à Insulina , Sobrecarga de Ferro/metabolismo , Músculo Esquelético/efeitos dos fármacos , Ácido Palmítico/farmacologia , Receptores da Transferrina/metabolismo , Adulto , Animais , Antígenos CD/genética , Estudos de Casos e Controles , Células Cultivadas , Desferroxamina/farmacologia , Diabetes Mellitus Tipo 2/metabolismo , Ativação Enzimática , Técnicas de Silenciamento de Genes , Humanos , Quelantes de Ferro/farmacologia , MAP Quinase Quinase 4/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Músculo Esquelético/citologia , Músculo Esquelético/metabolismo , Receptores da Transferrina/genética
12.
Mol Biol Rep ; 47(6): 4285-4293, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32418112

RESUMO

Chemokines interact with hepatic resident cells during inflammation and fibrosis. CC chemokine ligand (CCL) 20 has been reported to be important in inflammation and fibrosis in the liver. We hypothesized that visfatin, an adipocytokine, could play a role in hepatic fibrosis via CCL20. We investigated the effect of visfatin on CCL20 in THP-1 human promonocytic cells and examined the molecular mechanisms involved. Following treatment of THP-1 cells with visfatin, CCL20 expression and secretion were assessed. We assessed the intracellular signaling molecules IKK/NF-κB, JAK2/STAT3, MAPKs, and MKK3/6 by western blotting. We treated THP-1 cells with visfatin and signaling inhibitors, and examined CCL20 mRNA and protein levels. To investigate the effect of visfatin-induced CCL20 expression in hepatic stellate cells (HSCs), LX-2 cells were co-cultured with the culture supernatant of THP-1 cells with or without anti-CCL20 neutralizing antibodies, and fibrosis markers were examined by RT-PCR and immunoblotting. In THP-1 cells, visfatin increased the CCL20 mRNA and protein levels. visfatin increased the activities of the NF-κB, p38, and MLK3/6 signaling pathways but not those of the JAK2/STAT3 and ERK pathways. Visfatin treatment together with an NF-κB, p38, or MLK3 inhibitor reduced the mRNA and protein levels of CCL20. The visfatin-induced CCL20 increased the expression of fibrosis markers and CCR6 in HSCs. Following neutralization of CCL20, the levels of fibrosis markers and CCR6 were decreased. Visfatin increases the expression of CCL20 via the NF-κB and MKK3/6-p38 signaling pathways in macrophages, and visfatin-induced CCL20 expression promotes the fibrosis markers in HSCs.


Assuntos
Quimiocina CCL20/metabolismo , Células Estreladas do Fígado/metabolismo , Nicotinamida Fosforribosiltransferase/farmacologia , Quimiocina CCL20/fisiologia , Quimiocinas/metabolismo , Hepatócitos/metabolismo , Humanos , Janus Quinase 2/metabolismo , MAP Quinase Quinase 3/metabolismo , MAP Quinase Quinase 6/metabolismo , Sistema de Sinalização das MAP Quinases/fisiologia , Macrófagos/metabolismo , NF-kappa B/metabolismo , Nicotinamida Fosforribosiltransferase/metabolismo , Fator de Transcrição STAT3/metabolismo , Transdução de Sinais/efeitos dos fármacos , Células THP-1 , Fator de Transcrição RelA/metabolismo
13.
Nature ; 516(7529): 108-11, 2014 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-25383523

RESUMO

Lysosomal degradation of cytoplasmic components by autophagy is essential for cellular survival and homeostasis under nutrient-deprived conditions. Acute regulation of autophagy by nutrient-sensing kinases is well defined, but longer-term transcriptional regulation is relatively unknown. Here we show that the fed-state sensing nuclear receptor farnesoid X receptor (FXR) and the fasting transcriptional activator cAMP response element-binding protein (CREB) coordinately regulate the hepatic autophagy gene network. Pharmacological activation of FXR repressed many autophagy genes and inhibited autophagy even in fasted mice, and feeding-mediated inhibition of macroautophagy was attenuated in FXR-knockout mice. From mouse liver chromatin immunoprecipitation and high-throughput sequencing data, FXR and CREB binding peaks were detected at 178 and 112 genes, respectively, out of 230 autophagy-related genes, and 78 genes showed shared binding, mostly in their promoter regions. CREB promoted autophagic degradation of lipids, or lipophagy, under nutrient-deprived conditions, and FXR inhibited this response. Mechanistically, CREB upregulated autophagy genes, including Atg7, Ulk1 and Tfeb, by recruiting the coactivator CRTC2. After feeding or pharmacological activation, FXR trans-repressed these genes by disrupting the functional CREB-CRTC2 complex. This study identifies the new FXR-CREB axis as a key physiological switch regulating autophagy, resulting in sustained nutrient regulation of autophagy during feeding/fasting cycles.


Assuntos
Autofagia/genética , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Regulação da Expressão Gênica , Receptores Citoplasmáticos e Nucleares/metabolismo , Animais , Jejum/fisiologia , Regulação da Expressão Gênica/efeitos dos fármacos , Isoxazóis/farmacologia , Fígado/citologia , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Ligação Proteica , Receptores Citoplasmáticos e Nucleares/agonistas
14.
Retina ; 39(4): 648-655, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29232334

RESUMO

PURPOSE: To evaluate the 52-week safety and efficacy of intravitreal ziv-aflibercept in patients with neovascular age-related macular degeneration. METHODS: All patients received three monthly intravitreal injections of 0.05 mL of ziv-aflibercept (1.25 mg) followed by a pro re nata regimen. The best-corrected visual acuity and spectral domain optical coherence tomography were obtained at baseline and monthly. Full-field and multifocal electroretinograms were obtained at baseline and 4, 13, 26, and 52 weeks. For some full-field electroretinography parameters, we calculated the differences between baseline and 52 weeks and then compared those differences between treated and untreated fellow eyes. RESULTS: Fifteen patients were included and 14 completed the 52-week follow-up. The mean best-corrected visual acuity improved from 0.95 ± 0.41 (20/200) at baseline to 0.75 ± 0.51 (20/125) logarithm of the minimum angle of resolution at 52 weeks (P = 0.0066). The baseline central retinal thickness decreased from 478.21 ± 153.48 µm to 304.43 ± 98.59 µm (P = 0.0004) at 52 weeks. Full-field electroretinography parameters used to assess retinal toxicity after intravitreal injections (rod response and oscillatory potentials) remained unchanged during follow-up. The average multifocal electroretinography macular response in 5° showed increased N1-P1 amplitude and decreased P1 implicit time (P < 0.05). One patient presented with intraocular inflammation after the seventh intravitreal procedure. CONCLUSION: The results suggested that intravitreal ziv-aflibercept might be safe and effective for treating neovascular age-related macular degeneration. More patients and a longer follow-up are needed to confirm the long-term outcomes of intravitreal ziv-aflibercept.


Assuntos
Inibidores da Angiogênese/uso terapêutico , Neovascularização de Coroide/tratamento farmacológico , Receptores de Fatores de Crescimento do Endotélio Vascular/uso terapêutico , Proteínas Recombinantes de Fusão/uso terapêutico , Degeneração Macular Exsudativa/tratamento farmacológico , Idoso , Inibidores da Angiogênese/efeitos adversos , Neovascularização de Coroide/diagnóstico , Neovascularização de Coroide/fisiopatologia , Eletrorretinografia , Feminino , Seguimentos , Humanos , Injeções Intravítreas , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Proteínas Recombinantes de Fusão/efeitos adversos , Retina/fisiologia , Tomografia de Coerência Óptica , Resultado do Tratamento , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Acuidade Visual/fisiologia , Degeneração Macular Exsudativa/diagnóstico , Degeneração Macular Exsudativa/fisiopatologia
15.
Diabet Med ; 34(11): 1591-1598, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28734090

RESUMO

AIMS: To evaluate the association between sleep duration and the risk of progression to diabetes among people with prediabetes, defined by HbA1c values. METHODS: We conducted a cohort study in 17 983 adults who underwent health check-up examinations, including assessments of sleep duration and quality. Diabetes was defined as either HbA1c ≥48 mmol/mol (6.5%), or the use of antidiabetic medication. Time-dependent proportional hazards models were used to evaluate the association between sleep duration and the risk of progression to diabetes. RESULTS: During 31,582 person-years of follow-up, 664 incident cases of diabetes were identified; the incidence rate was 21.0 per 1000 person-years. The multivariate adjusted hazard ratios for progression to diabetes in people with sleep durations of ≤5, 6 and ≥8 h compared with 7 h were 1.68 (95% CI 1.30-2.16), 1.44 (95% CI 1.17-1.76) and 1.23 (95% CI 0.85-1.78), respectively (P for quadratic trend <0.001). This association was partially mediated by biomarkers of adiposity, fatty liver and insulin resistance. CONCLUSION: In this large study in young and middle-aged adults with prediabetes, we found an association between short sleep duration and the risk of progression to diabetes. Our findings suggest that sufficient sleep duration is important for delaying or preventing the progression of prediabetes to diabetes.


Assuntos
Diabetes Mellitus Tipo 2/diagnóstico , Diabetes Mellitus Tipo 2/fisiopatologia , Hemoglobinas Glicadas/análise , Estado Pré-Diabético/patologia , Estado Pré-Diabético/fisiopatologia , Sono/fisiologia , Adulto , Estudos de Coortes , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/epidemiologia , Progressão da Doença , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estado Pré-Diabético/sangue , Estado Pré-Diabético/epidemiologia , República da Coreia/epidemiologia
16.
Soft Matter ; 13(42): 7753-7759, 2017 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-29018860

RESUMO

Polymeric thin films coated on non-wettable substrates undergo film-instabilities, which are usually manifested as surface deformation in the form of dewetting or wrinkling. The former takes place in fluidic films, whereas the latter occurs in solid films. Therefore, there have rarely been reports of systems involving simultaneous deformations of dewetting and wrinkling. In this study, we propose polymeric thin films of liquid crystalline (LC) mesogens prepared on a non-wettable Si substrate and apply a treatment of plasma irradiation to form a thin polymerized layer at the surface. The resulting compressive stress generated in the surface region drives the formation of wrinkles, while at the same time, dipolar attraction between LC molecules induces competitive cohesive dewetting. Intriguing surface structures were obtained whereby dewetting-like hole arrays are nested inside the randomly propagated wrinkles. The structural features are readily controlled by the degree of surface cross-linking, hydrophilicity of the substrates, and the LC film thickness. In particular, dewetting of LC mesogens is observed to be restricted to occur at the trough regions of wrinkles, exhibiting the typical behavior of geometrically confined dewetting. Finally, wrinkling-dewetting mixed structures are separated from the substrate in the form of free standing films to demonstrate the potential applicability as membranes.

18.
Proc Natl Acad Sci U S A ; 109(40): 16137-42, 2012 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-22988100

RESUMO

MicroRNA-34a (miR-34a) is the most highly elevated hepatic miR in obese mice and is also substantially elevated in patients who have steatosis, but its role in obesity and metabolic dysfunction remains unclear. After a meal, FGF19 is secreted from the ileum; binds to a hepatic membrane receptor complex, FGF19 receptor 4 and coreceptor ß-Klotho (ßKL); and mediates postprandial responses under physiological conditions, but hepatic responses to FGF19 signaling were shown to be impaired in patients with steatosis. Here, we show an unexpected functional link between aberrantly elevated miR-34a and impaired ßKL/FGF19 signaling in obesity. In vitro studies show that miR-34a down-regulates ßKL by binding to the 3' UTR of ßKL mRNA. Adenoviral-mediated overexpression of miR-34a in mice decreased hepatic ßKL levels, impaired FGF19-activated ERK and glycogen synthase kinase signaling, and altered expression of FGF19 metabolic target genes. Consistent with these results, ßKL levels were decreased and hepatic responses to FGF19 were severely impaired in dietary obese mice that have elevated miR-34a. Remarkably, in vivo antisense inhibition of miR-34a in obese mice partially restored ßKL levels and improved FGF19 target gene expression and metabolic outcomes, including decreased liver fat. Further, anti-miR-34a treatment in primary hepatocytes of obese mice restored FGF19-activated ERK and glycogen synthase kinase signaling in a ßKL-dependent manner. These results indicate that aberrantly elevated miR-34a in obesity attenuates hepatic FGF19 signaling by directly targeting ßKL. The miR-34a/ßKL/FGF19 axis may present unique therapeutic targets for FGF19-related human diseases, including metabolic disorders and cancer.


Assuntos
Fatores de Crescimento de Fibroblastos/metabolismo , Fígado/metabolismo , Proteínas de Membrana/metabolismo , MicroRNAs/metabolismo , Obesidade/metabolismo , Período Pós-Prandial/fisiologia , Transdução de Sinais/fisiologia , Animais , Primers do DNA/genética , Humanos , Proteínas Klotho , Luciferases , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Obesidade/fisiopatologia , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase em Tempo Real
19.
J Biol Chem ; 288(32): 23252-63, 2013 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-23824184

RESUMO

Bile acids (BAs) are recently recognized key signaling molecules that control integrative metabolism and energy expenditure. BAs activate multiple signaling pathways, including those of nuclear receptors, primarily farnesoid X receptor (FXR), membrane BA receptors, and FXR-induced FGF19 to regulate the fed-state metabolism. Small heterodimer partner (SHP) has been implicated as a key mediator of these BA signaling pathways by recruitment of chromatin modifying proteins, but the key question of how SHP transduces BA signaling into repressive histone modifications at liver metabolic genes remains unknown. Here we show that protein kinase Cζ (PKCζ) is activated by BA or FGF19 and phosphorylates SHP at Thr-55 and that Thr-55 phosphorylation is critical for the epigenomic coordinator functions of SHP. PKCζ is coimmunopreciptitated with SHP and both are recruited to SHP target genes after bile acid or FGF19 treatment. Activated phosphorylated PKCζ and phosphorylated SHP are predominantly located in the nucleus after FGF19 treatment. Phosphorylation at Thr-55 is required for subsequent methylation at Arg-57, a naturally occurring mutation site in metabolic syndrome patients. Thr-55 phosphorylation increases interaction of SHP with chromatin modifiers and their occupancy at selective BA-responsive genes. This molecular cascade leads to repressive modifications of histones at metabolic target genes, and consequently, decreased BA pools and hepatic triglyceride levels. Remarkably, mutation of Thr-55 attenuates these SHP-mediated epigenomic and metabolic effects. This study identifies PKCζ as a novel key upstream regulator of BA-regulated SHP function, revealing the role of Thr-55 phosphorylation in epigenomic regulation of liver metabolism.


Assuntos
Ácidos e Sais Biliares/metabolismo , Epigênese Genética/fisiologia , Fígado/metabolismo , Proteína Quinase C-épsilon/metabolismo , Receptores Citoplasmáticos e Nucleares/metabolismo , Transdução de Sinais/fisiologia , Animais , Ácidos e Sais Biliares/genética , Fatores de Crescimento de Fibroblastos/genética , Fatores de Crescimento de Fibroblastos/metabolismo , Células Hep G2 , Humanos , Masculino , Metilação , Camundongos , Camundongos Endogâmicos BALB C , Mutação , Fosforilação/fisiologia , Proteína Quinase C-épsilon/genética , Receptores Citoplasmáticos e Nucleares/genética
20.
Bone Joint J ; 106-B(3): 240-248, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38423112

RESUMO

Aims: The aim of this study was to evaluate whether achieving medial joint opening, as measured by the change in the joint line convergence angle (∆JLCA), is a better predictor of clinical outcomes after high tibial osteotomy (HTO) compared with the mechanical axis deviation, and to find individualized targets for the redistribution of load that reflect bony alignment, joint laxity, and surgical technique. Methods: This retrospective study analyzed 121 knees in 101 patients. Patient-reported outcome measures (PROMs) were collected preoperatively and one year postoperatively, and were analyzed according to the surgical technique (opening or closing wedge), postoperative mechanical axis deviation (deviations above and below 10% from the target), and achievement of medial joint opening (∆JLCA > 1°). Radiological parameters, including JLCA, mechanical axis deviation, and the difference in JLCA between preoperative standing and supine radiographs (JLCAPD), an indicator of medial soft-tissue laxity, were measured. Cut-off points for parameters related to achieving medial joint opening were calculated from receiver operating characteristic (ROC) curves. Results: Patients in whom the medial joint opening was achieved had significantly better postoperative PROMs compared with those without medial opening (all p < 0.05). Patients who were outliers with deviation of > 10% from the target mechanical axis deviation had significantly similar PROMs compared with patients with an acceptable axis deviation (all p > 0.05). Medial joint opening was affected by postoperative mechanical axis deviation and JLCAPD. The influence of JLCAPD on postoperative axis deviation was more pronounced in a closing wedge than in an opening wedge HTO. Conclusion: Medial joint opening rather than the mechanical axis deviation determined the clinical outcome in patients who underwent HTO. The JLCAPD identified the optimal postoperative axis deviation necessary to achieve medial joint opening. For patients with increased laxity, lowering the target axis deviation is recommended to achieve medial joint opening. The target axis deviation should also differ according to the technique of undergoing HTO.


Assuntos
Articulação do Joelho , Osteoartrite do Joelho , Humanos , Articulação do Joelho/diagnóstico por imagem , Articulação do Joelho/cirurgia , Osteoartrite do Joelho/diagnóstico por imagem , Osteoartrite do Joelho/cirurgia , Osteoartrite do Joelho/etiologia , Estudos Retrospectivos , Tíbia/diagnóstico por imagem , Tíbia/cirurgia , Osteotomia/métodos
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