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1.
Biochem Biophys Res Commun ; 479(4): 793-799, 2016 Oct 28.
Artículo en Inglés | MEDLINE | ID: mdl-27687546

RESUMEN

The Wnt signalling pathway in beta-cells has been linked to the development of type 2 diabetes. Investigating the impact of a non-canonical Wnt ligand, Wnt4, on beta-cell function we found that in INS-1 cells, Wnt4 was able to completely block Wnt3a stimulated cell growth and insulin secretion. However, despite high levels of Wnt4 protein being detected in INS-1 cells, reducing the expression of Wnt4 had no impact on cell growth or Wnt3a signalling. As such, the role of the endogenously expressed Wnt4 in beta-cells is unclear, but the data showing that Wnt4 can act as a negative regulator of canonical Wnt signalling in beta-cells suggests that this pathway could be a potential target for modulating beta-cell function.


Asunto(s)
Células Secretoras de Insulina/metabolismo , Proteína Wnt3A/metabolismo , Proteína Wnt4/metabolismo , Animales , Línea Celular , Proliferación Celular , Glucosa/metabolismo , Glucosa/farmacología , Humanos , Inmunohistoquímica , Insulina/metabolismo , Secreción de Insulina , Células Secretoras de Insulina/citología , Células Secretoras de Insulina/efectos de los fármacos , Islotes Pancreáticos/citología , Islotes Pancreáticos/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , ARN Interferente Pequeño/genética , Ratas , Vía de Señalización Wnt , Proteína Wnt3A/antagonistas & inhibidores , Proteína Wnt3A/farmacología , Proteína Wnt4/genética , Proteína Wnt4/farmacología , beta Catenina/genética , beta Catenina/metabolismo
2.
Clin Endocrinol (Oxf) ; 72(3): 334-41, 2010 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-19549246

RESUMEN

INTRODUCTION: Zinc-alpha2-glycoprotein (ZAG) is a novel adipokine, which may act locally to influence adipocyte metabolism. This study assessed the effect of increased adiposity on ZAG expression in adipose tissue in human subjects. The study also examined the association between ZAG and adiponectin expression in human adipose tissue, and whether ZAG modulates adiponectin secretion by human adipocytes. METHODS: Adipose tissue (visceral and subcutaneous) was collected from human subjects with a wide range of BMIs. Human Simpson-Golabi-Behmel syndrome (SGBS) adipocytes were used for in vitro studies. ZAG mRNA levels were quantified by real-time PCR and protein by Western blotting. RESULTS: In human subjects, ZAG mRNA level was negatively correlated with BMI (r = -0.61, P < 0.001, n = 23, visceral; r = -0.6, P < 0.05, n = 14, subcutaneous) and fat mass (r = -0.62, P < 0.01, visceral; r = -0.6, P < 0.05, subcutaneous). Negative associations were also found between ZAG mRNA and insulin resistance parameters including plasma insulin (r = -0.65, P < 0.001, visceral; r = -0.55, P < 0.05, subcutaneous) and homeostasis model of insulin resistance (HOMA-IR) (r = -0.65, P < 0.001, visceral; r = -0.52, P = 0.055, subcutaneous), and C reactive protein (CRP) (r = -0.46, P < 0.05, visceral; r = -0.53, P < 0.05, subcutaneous). However, ZAG mRNA was positively correlated with adiponectin (r = 0.5, P < 0.05, visceral; r = 0.82, P < 0.001, subcutaneous) but negatively associated with leptin mRNA (r = -0.42, P < 0.05, visceral; r = -0.54, P < 0.05, subcutaneous). ZAG secretion by differentiated human adipocytes was abundant. Addition of recombinant ZAG stimulated adiponectin release from human adipocytes. CONCLUSION: ZAG gene expression in adipose tissue is downregulated with increased adiposity and circulating insulin. ZAG mRNA is positively correlated with adiponectin mRNA, and ZAG enhances adiponectin production by human adipocytes. We suggest that ZAG is linked to obesity and obesity-related insulin resistance.


Asunto(s)
Adipoquinas/metabolismo , Adiponectina/metabolismo , Grasa Intraabdominal/metabolismo , Obesidad/metabolismo , Proteínas de Plasma Seminal/metabolismo , Grasa Subcutánea Abdominal/metabolismo , Adipocitos/metabolismo , Adiposidad , Adulto , Femenino , Expresión Génica , Humanos , Resistencia a la Insulina , Leptina/metabolismo , Masculino , Persona de Mediana Edad , ARN Mensajero/metabolismo , Zn-alfa-2-Glicoproteína
3.
Diabetes Obes Metab ; 12(4): 360-3, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-20380658

RESUMEN

In this study, the regional adipose tissue-adiponectin (AT-ADN) and adiponectin receptor (R1 and R2) expression and their relation with metabolic parameters, circulating and AT-derived cytokine expressions were compared. Paired subcutaneous adipose tissue (SCAT) and visceral adipose tissue (VAT) were taken from 18 lean and 39 obese humans, AT-mRNA expression of adipokines analysed by RT-PCR and corresponding serum levels by enzyme-linked immunosorbent assay (ELISA). R1 and R2 adipocyte expression was compared with 17 other human tissues. ADN-gene expression was lower in VAT than SCAT [mean (SD) 1.54 (1.1) vs. 2.84 (0.87); p < 0.001], and lower in obese subjects (VAT : p = 0.01;SCAT : p < 0.001). SCAT-ADN correlated positively with serum ADN (r = 0.33;p = 0.036) but not VAT-ADN. AT expressions of ADN and macrophage migration inhibiting factor (MMIF), IL18 and cluster of differentiation factor 14 (CD14) in both depots showed inverse correlations. R1 and R2 were expressed ubiquitously and R2 highest in SCAT, and this is much higher (x100) than R1 (x100). R expression was similar in lean and obese subjects and unrelated to the metabolic syndrome, however, receptors correlated with VAT-MMIF (R 1: r = 0.4;p = 0.008;R 2: r = 0.35,p = 0.02) and SCAT-MMIF expression (R 2: r = 0.43;p = 0.004). Unlike ADN, its receptors are expressed in many human tissues. Human R2 expression is not highest in the liver but in AT where it is associated with MMIF expression. The adiponectin-dependent insulin-sensitizing action of thiazolidinediones is thus probably to differ amongst species with weaker effects on the human liver.


Asunto(s)
Grasa Intraabdominal/metabolismo , Factores Inhibidores de la Migración de Macrófagos/metabolismo , Receptores de Adiponectina/metabolismo , Grasa Subcutánea/metabolismo , Adiponectina/metabolismo , Ensayo de Inmunoadsorción Enzimática , Humanos , Masculino
4.
Clin Endocrinol (Oxf) ; 70(3): 383-9, 2009 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-18616714

RESUMEN

OBJECTIVES: Ghrelin, an important central acting orexigenic hormone, is predominantly secreted in the gastrointestinal tract. However little is known about the action of ghrelin in human adipose tissue (AT). AIM: To study the expression of ghrelin in AT, the effects of octanoyl-(OTG) and des-acyl (DSG) ghrelin on lipolysis and lipogenesis, leptin release and potential peripheral signalling through the Y1 receptor. METHODS: Ex vivo human AT was obtained from women undergoing elective surgery (46 (mean +/- SD) 6.8 years, body mass index (BMI): 25.6 +/- 5.0 kg/m(2), n = 20). Abdominal-subcutaneous (AbdSc) adipocytes were isolated and treated with recombinant human (rh) OTG and DSG to assess lipid metabolism leptin release and the influence of Y1-receptor blocker. RESULTS: Ghrelin was expressed in AbdScAT and negatively correlated with BMI (lean: 3.6 +/- 0.74 optical-density-units (OD), obese: 1.64 +/- 0.45 OD, *P < 0.05). Only DSG significantly suppressed glycerol release (Control (C): 286 +/- 58 microl/l; DSG 1 nm: 224 +/- 38 microl/l downward arrow*; DSG 100 nm: 172 +/- 13 microl/l downward arrow*,* downward arrow P < 0.05, n = 7) and reduced hormone sensitive lipase expression (C: 1.0 +/- 0.3 OD; DSG 1 nm: 0.8 +/- 0.3 OD downward arrow*; DSG 100 nm: 0.6 +/- 0.1 OD downward arrow*, n = 4). However, both isoforms increased lipoprotein lipase expression (C: 1.0 +/- 0.3OD; DSG 100 nm: 0.2 +/- 0.4 OD upward arrow*; OTG 100 nm: 2.5 +/- 0.3 OD upward arrow*, n = 4), whilst blockade of Y1 eliminated this effect in both. Leptin was down-regulated by DSG only (DSG 1 nm: 5.3 +/- 0.7 ng/ml; DSG 100 nm: 4.1 +/- 0.7 ng/ml*) and was significant after BMI adjustment (P = 0.029). CONCLUSION: Ghrelin was expressed in human AbdSc AT. In vitro, both OGT and DSG appear to mediate fat deposition with the lipogenic effects in part mediated by the Y1 receptor, whilst the influence of DSG affected lipolysis, lipogenesis and leptin secretion. Taken together, these studies support a local action for ghrelin isoforms on lipid and adipokine metabolism that further supports a cross talk between organs.


Asunto(s)
Ghrelina/metabolismo , Grasa Subcutánea/metabolismo , Adipocitos/citología , Adipocitos/efectos de los fármacos , Adipocitos/metabolismo , Adulto , Arginina/análogos & derivados , Arginina/farmacología , Índice de Masa Corporal , Células Cultivadas , Femenino , Ghrelina/farmacología , Humanos , Leptina/metabolismo , Lipogénesis/efectos de los fármacos , Lipogénesis/fisiología , Lipólisis/efectos de los fármacos , Lipólisis/fisiología , Lipoproteína Lipasa/metabolismo , Persona de Mediana Edad , Receptores de Neuropéptido Y/antagonistas & inhibidores , Grasa Subcutánea/citología , Grasa Subcutánea/efectos de los fármacos
5.
Diabetes Obes Metab ; 11(4): 285-92, 2009 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-19175376

RESUMEN

CONTEXT: Dipeptidyl peptidase IV (DPP-IV) inactivates the incretin hormone glucagon-like peptide. It can also affect the orexigenic hormone neuropeptide Y (NPY(1-36)) which is truncated by DPP-IV to NPY(3-36), as a consequence NPY's affinity changes from receptor Y1, which mediates the antilipolytic function of NPY, to other NPY receptors. Little is known whether DPP-IV inhibitors for the treatment of type 2 diabetic (T2DM) patients could influence these pathways. AIMS: To investigate the in vitro effects of NPY with DPP-IV inhibition in isolated abdominal subcutaneous (AbdSc) adipocytes on fat metabolism, and assessment of NPY receptor and DPP-IV expression in adipose tissue (AT). METHODS: Ex vivo human AT was taken from women undergoing elective surgery (body mass index: 27.5 (mean +/- s.d.) +/- 5 kg/m2, age: 43.7 +/- 10 years, n = 36). Isolated AbdSc adipocytes were treated with human recombinant (rh)NPY (1-100 nM) with and without DPP-IV inhibitor (1 M); glycerol release and tissue distribution of DPP-IV, Y1 and Y5 messenger RNA (mRNA) were measured and compared between lean and obese subjects. RESULTS AND CONCLUSION: rhNPY reduced glycerol release, an effect that was further enhanced by co-incubation with a DPP-IV inhibitor [control: 224 (mean +/- s.e.) +/- 37 micromol/l; NPY, 100 nM: 161 +/- 27 micromol/l**; NPY 100 nM/DPP-IV inhibitor, 1 M: 127 +/- 14 micromol/l**; **p < 0.01, n = 14]. DPP-IV was expressed in AbdSc AT and omental AT with relative DPP-IV mRNA expression lower in AbdSc AT taken from obese [77 +/- 6 signal units (SU)] vs. lean subjects (186 +/- 29 SU*, n = 10). Y1 was predominantly expressed in fat and present in all fat depots but higher in obese subjects, particularly the AbdSc AT-depot (obese: 1944 +/- 111 SU vs. lean: 711 +/- 112 SU**, n = 10). NPY appears to be regulated by AT-derived DPP-IV. DPP-IV inhibitors augment the antilipolytic effect of NPY in AT. Further studies are required to show whether this explains the lack of weight loss in T2DM patients treated with DPP-IV inhibitors.


Asunto(s)
Adipocitos/efectos de los fármacos , Inhibidores de la Dipeptidil-Peptidasa IV/farmacología , Neuropéptido Y/farmacología , Grasa Subcutánea Abdominal/efectos de los fármacos , Adipocitos/metabolismo , Adulto , Células Cultivadas , Dipeptidil Peptidasa 4/metabolismo , Dipeptidil Peptidasa 4/fisiología , Femenino , Glicerol/metabolismo , Humanos , Lipólisis/efectos de los fármacos , Persona de Mediana Edad , Obesidad/metabolismo , Obesidad/patología , Proteínas Recombinantes/farmacología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Grasa Subcutánea Abdominal/metabolismo , Grasa Subcutánea Abdominal/patología
6.
Diabet Med ; 25(12): 1400-5, 2008 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19046237

RESUMEN

AIMS: Maternal leptin affects placental growth hormone (GH), whereas ghrelin, a natural ligand of the growth-hormone-secretagogue receptor, modulates GH action. Both hormones may affect fetal growth, and dysregulation in diabetes may lead to fetal growth disturbances. The aim was to investigate changes in maternal ghrelin during pregnancy with diabetes and to establish reference leptin levels. METHODS: Twelve healthy non-diabetic (ND) and 12 pregnant women with Type 1 diabetes (T1DM) were recruited. Age and body mass index (BMI) [ND: age 29.9 +/- 4.7 years (mean +/- sd), BMI 25.2 +/- 3.7 kg/m2; T1DM: age 31 +/- 5.5 years, BMI 27 +/- 3.1 kg/m2] were similar in the groups. HbA1c in T1DM was 6.2 +/- 1.1% at 20 weeks, 6.3 +/- 1.1% at 30 weeks' gestation and 7.8 +/- 2.1% postpartum. Fasting plasma ghrelin, total leptin, free leptin (FL) and soluble leptin receptor (sOB-R) levels were measured at 20 and 30 weeks' gestation and postpartum and determined by radioimmunoassay. RESULTS: All pregnancies resulted in full-term singleton births with no differences in birth weight between groups [T1DM: 3.4 +/- 0.56 kg (mean +/- SE); ND: 3.6 +/- 0.3 kg, P = NS]. Ghrelin levels were lower in T1DM when corrected for age and mothers' weight (T1DM: 458 +/- 36 pg/ml and 432.9 +/- 26.6 pg/ml; ND: 562 +/- 52 pg/ml and 515.8 +/- 63 pg/ml at 20 and 30 weeks, respectively, P < 0.05). T1DM mothers had higher levels of sOB-R and FL levels declined at 30 weeks' gestation in T1DM (P = 0.04) but not in ND. CONCLUSION: In a population of pregnant women with expected changes in leptin levels as previously reported, ghrelin levels were lower in T1DM pregnancies at 20 and 30 weeks. This may have implications for fetal development and requires further study in diabetes, particularly in pregnancies that result in macrosomia.


Asunto(s)
Diabetes Mellitus Tipo 1/sangre , Ghrelina/metabolismo , Leptina/metabolismo , Embarazo en Diabéticas/sangre , Adulto , Peso al Nacer/fisiología , Femenino , Desarrollo Fetal/fisiología , Hormona del Crecimiento/metabolismo , Humanos , Embarazo , Resultado del Embarazo , Valores de Referencia , Adulto Joven
7.
Diabetes Metab ; 43(3): 240-247, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28131740

RESUMEN

AIMS: Obstructive sleep apnea syndrome (OSAS) is associated with increased cardiovascular risk and diabetes independent of obesity. We investigated whether adipose tissue dysfunction is exacerbated due to increased tissue hypoxia. METHODS: Adipose tissue (AT) oxygenation was measured with a Clarke-type electrode (pATO2) in 16 men with OSAS before and after 4 months of continuous positive airway pressure therapy (CPAP) and in BMI-matched controls. Oxygenation was simultaneously monitored in arterial blood by pulse oximetry (SaO2); mixed blood in AT microcirculation by reflectance spectroscopy (SATO2) along with blood flow. Markers of hypoxia, adipo- and angiogenesis, inflammation and fibrosis were analysed in AT and serum. RESULTS: OSAS subjects were more insulin resistant. Despite lower arterial SaO2 (95.4±1.3% vs. 97.1±1.6%, P=0.013) in subjects with OSAS, there was no difference in the oxygen content of AT microcirculation (61.6±18.4 vs. 72.2±7.0%, P=0.07) or pATO2 (49.2±7.5 vs. 50.4±14.7mmHg, P=0.83) between groups. Resting AT blood flow was higher in OSAS compared to controls (108.5±22.7 vs. 78.9±24.9au, P<0.005) and strongly associated with inflammation markers IL-6 and MCP-1. AT of OSAS subjects showed increased inflammation (TNFA P=0.049) and fibrosis (COL3A1 P=0.02), a trend of higher HIF1A expression (P=0.06) and reduced adipogenesis (PPARG P=0.006). After CPAP, only expression of the lipid deposition marker LPL increased (30%, P=0.047). CONCLUSIONS: Adipose tissue of awake OSAS subjects appears no more hypoxic than adipose tissue of BMI-matched controls despite daytime hypoxaemia. Increased adipose tissue blood flow may be explained by an increased inflammatory response. We observe features of adipose dysfunction in subjects with OSAS, which attribute to increased cardiometabolic risk associated with this condition.


Asunto(s)
Tejido Adiposo/fisiopatología , Hipoxia/fisiopatología , Obesidad/fisiopatología , Apnea Obstructiva del Sueño/fisiopatología , Tejido Adiposo/metabolismo , Anciano , Estudios de Casos y Controles , Humanos , Hipoxia/metabolismo , Resistencia a la Insulina , Masculino , Persona de Mediana Edad , Obesidad/metabolismo , Oxígeno/análisis , Oxígeno/metabolismo , Apnea Obstructiva del Sueño/metabolismo
8.
Nutr Diabetes ; 6(12): e235, 2016 12 12.
Artículo en Inglés | MEDLINE | ID: mdl-27941938

RESUMEN

BACKGROUND/OBJECTIVES: Subjects with type-2 diabetes are typically obese with dysfunctional adipose tissue (AT). Glucagon-like peptide-1 (GLP-1) analogues are routinely used to improve glycaemia. Although, they also aid weight loss that improves AT function, their direct effect on AT function is unclear. To explore GLP-1 analogues' influence on human AT's cytokine and extracellular matrix (ECM) regulation, we therefore obtained and treated omental (OMAT) and subcutaneous (SCAT) AT samples with Exendin-4, an agonist of the GLP-1 receptor (GLP-1R). SUBJECTS/METHODS: OMAT and abdominal SCAT samples obtained from women during elective surgery at the Royal Devon & Exeter Hospital (UK) were treated with increasing doses of Exendin-4. Changes in RNA expression of adipokines, inflammatory cytokines, ECM components and their regulators were assessed and protein secretion analysed by ELISA. GLP-1R protein accumulation was compared in paired AT depot samples. RESULTS: Exendin-4 induced an increase in OMAT adiponectin (P=0.02) and decrease in elastin expression (P=0.03) in parallel with reduced elastin secretion (P=0.04). In contrast to OMAT, we did not observe an effect on SCAT. There was no change in the expression of inflammatory markers (CD14, TNFA, MCP-1), collagens, TGFB1 or CTGF. GLP-1R accumulation was higher in SCAT. CONCLUSIONS: Independently of weight loss, which may bias findings of in vivo studies, GLP-1 analogues modify human OMAT physiology favourably by increasing the insulin-sensitising cytokine adiponectin. However, the reduction of elastin and no apparent effect on AT's inflammatory cytokines suggest that GLP-1 analogues may be less beneficial to AT function, especially if there is no associated weight loss.


Asunto(s)
Adipoquinas/metabolismo , Tejido Adiposo/efectos de los fármacos , Citocinas/metabolismo , Matriz Extracelular/efectos de los fármacos , Incretinas/farmacología , Inflamación/metabolismo , Péptidos/farmacología , Ponzoñas/farmacología , Adipoquinas/genética , Adiponectina/genética , Adiponectina/metabolismo , Tejido Adiposo/metabolismo , Anciano , Citocinas/genética , Relación Dosis-Respuesta a Droga , Elastina/genética , Elastina/metabolismo , Exenatida , Matriz Extracelular/metabolismo , Femenino , Receptor del Péptido 1 Similar al Glucagón/agonistas , Humanos , Persona de Mediana Edad , Sobrepeso/metabolismo
9.
J Prev Alzheimers Dis ; 3(1): 43-52, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-29214280

RESUMEN

Emerging evidence suggests that low vitamin D concentrations are potentially involved in the pathogenesis of dementia. This is of particular interest when considering the high prevalence of vitamin D deficiency in elderly adults and the urgent need to identify modifiable risk factors for dementia. Studies have found that vitamin D is implicated in procognitive and neuroprotective functions, including the reduction of Alzheimer's disease hallmarks such as amyloid beta and phosphorylated tau. Cross-sectional studies have consistently found that vitamin D concentrations are significantly lower in individuals with Alzheimer's disease and cognitive impairment compared to healthy controls. Longitudinal studies support an association between low vitamin D concentrations and an increased risk of dementia and cognitive decline. Neuroimaging studies are beginning to uncover the potential neurodegenerative and cerebrovascular mechanisms that underlie these associations such as white matter hyperintensities and enlarged ventricular volume, although there is currently a lack of longitudinal studies. In contrast to observational studies, findings from interventional studies have produced mixed results on the benefits of vitamin D supplementation on dementia and cognitive outcomes. Interpretation of the findings from these studies is hampered by several major methodological limitations, such as small sample sizes, inadequate doses and inclusion of participants unlikely to benefit from vitamin D supplementation. There is a need for large double-blind randomised-control trials investigating whether vitamin D supplementation can halt or delay the risk of dementia-related outcomes in individuals with low vitamin D concentrations.

10.
Mol Endocrinol ; 14(3): 429-39, 2000 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-10707960

RESUMEN

Activin, a member of the transforming growth factor-beta superfamily, can regulate neuropeptide gene expression in the nervous system and in neuroblastoma cells. Among the neuropeptide genes whose expression can be regulated by activin is the gene encoding the neuropeptide vasoactive intestinal peptide (VIP). To investigate the molecular mechanisms by which activin regulates neuronal gene expression, we have examined activin's regulation of VIP gene expression in NBFL neuroblastoma cells. We report here that NBFL cells respond to activin by increasing expression of VIP mRNA. Activin regulates VIP gene transcription in NBFL cells through a 180-bp element in the VIP promoter that was previously characterized to be necessary and sufficient to mediate the induction of VIP by the neuropoietic cytokines and termed the cytokine response element (CyRE). We find that the VIP CyRE is necessary and sufficient to mediate the transcriptional response to activin. In addition, ciliary neurotrophic factor (CNTF), a neuropoietic cytokine, synergizes with activin to increase VIP mRNA expression and transcription through the VIP CyRE. Mutations in either the Stat (signal transducer and activator of transcription) or AP-1 sites within the CyRE that reduce the response to CNTF, also reduce the response to activin. However, mutating both the Stat and AP-1 sites within the wild-type CyRE, while reducing the separate responses to either activin or CNTF, eliminates the synergy between them. These data suggest that activin and CNTF, two factors that appear to signal though distinct pathways, activate VIP gene transcription through a common transcriptional element, the VIP CyRE.


Asunto(s)
Factor Neurotrófico Ciliar/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Inhibinas/farmacología , Secuencias Reguladoras de Ácidos Nucleicos , Transducción de Señal/efectos de los fármacos , Péptido Intestinal Vasoactivo/biosíntesis , Activinas , Animales , Sitios de Unión/genética , Pollos , Proteínas de Unión al ADN/metabolismo , Sinergismo Farmacológico , Humanos , Mutación , Proteínas de Neoplasias/biosíntesis , Proteínas de Neoplasias/genética , Neuroblastoma/metabolismo , Neuroblastoma/patología , Regiones Promotoras Genéticas , Proteínas Recombinantes de Fusión/biosíntesis , Factor de Transcripción STAT1 , Transactivadores/metabolismo , Factor de Transcripción AP-1/metabolismo , Transfección , Factor de Crecimiento Transformador beta/farmacología , Células Tumorales Cultivadas/efectos de los fármacos , Péptido Intestinal Vasoactivo/genética
11.
Gene ; 210(1): 71-8, 1998 Mar 27.
Artículo en Inglés | MEDLINE | ID: mdl-9524226

RESUMEN

The ETS gene family encodes a group of proteins that function as transcription factors under physiological conditions and, if aberrantly expressed, can lead to cellular transformation. ETS transcription factors are characterized by a unique conserved DNA binding domain. A subset of these proteins is rearranged with EWS in Ewing tumors (ET). We recently described a spectrum of ETS genes coexpressed with EWS-FLI1 in an ETcell line to define proteins that potentially compete in target site selection. We now report on the cloning and characterization of a novel ETS family member, ELFR, displaying 92% homology to ELF-1 in its DNA binding domain while diverging in the rest of the protein. ELFR expression was found in a very tissue restricted pattern with the highest abundancy in placenta. We also report the chromosomal assignment of ELFR and ELF-1 to Xq26 and 13q13, respectively, by means of fluorescence in-situ hybridization (FISH).


Asunto(s)
Mapeo Cromosómico , Proteínas de Unión al ADN/química , Sarcoma de Ewing/química , Factores de Transcripción/química , Secuencia de Aminoácidos , Cromosomas Humanos Par 13/genética , Clonación Molecular , Proteínas de Unión al ADN/genética , Regulación Neoplásica de la Expresión Génica/genética , Genes Relacionados con las Neoplasias/genética , Genes Reporteros/genética , Humanos , Hibridación Fluorescente in Situ , Datos de Secuencia Molecular , ARN Mensajero/metabolismo , Alineación de Secuencia , Análisis de Secuencia de ADN , Factores de Transcripción/genética , Células Tumorales Cultivadas , Cromosoma X/genética
12.
Psychopharmacology (Berl) ; 158(1): 87-93, 2001 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11685388

RESUMEN

RATIONALE: Various studies have shown that stressful manipulations in rats and mice lower the convulsant potency of GABA-related, but also some GABA-unrelated convulsants. The mechanism of this anticonvulsive effect of stress is still unknown. OBJECTIVES: We tested the possible involvement of alpha2-adrenoceptors in the previously observed anticonvulsive effect of swim stress. METHODS: The mice were, prior to exposure to swim stress and the IV infusion of picrotoxin, pre-treated with clonidine (an alpha2-adrenoceptor agonist), yohimbine (a non-selective alpha2-adrenoceptor antagonist), idazoxan (a selective alpha2-adrenoceptor antagonist), or niguldipine (an alpha1-adrenoceptor antagonist), and the latency to the onset of two convulsant signs was registered. RESULTS: In control unstressed animals clonidine (0.1 and 1 mg/kg IP), yohimbine (2 mg/kg IP) and idazoxan (1 mg/kg IP) failed to affect the doses of picrotoxin needed to produce convulsant signs, while niguldipine (5 mg/kg IP) prolonged the latency, i.e. it enhanced the doses of picrotoxin producing running/bouncing clonus and tonic hindlimb extension. In swim stressed mice clonidine enhanced, while idazoxan decreased doses of picrotoxin needed to produce two convulsive signs. Yohimbine decreased the dose of convulsant needed to produce tonic hindlimb extension, while niguldipine enhanced doses of picrotoxin needed to produce both symptoms. CONCLUSIONS: The results demonstrate the alpha2-adrenoceptor agonist-induced potentiation and alpha2-adrenoceptor antagonist-induced diminution of the anticonvulsive effect of stress. Additionally, they show the anticonvulsive effect of niguldipine in unstressed and stressed animals. Hence, the results suggest that alpha2-adrenoceptors are involved in the anticonvulsive effect of swim stress in mice.


Asunto(s)
Receptores Adrenérgicos alfa 2/fisiología , Convulsiones/prevención & control , Estrés Fisiológico/fisiopatología , Natación , Agonistas Adrenérgicos/administración & dosificación , Agonistas Adrenérgicos/farmacología , Antagonistas Adrenérgicos/administración & dosificación , Antagonistas Adrenérgicos/farmacología , Agonistas de Receptores Adrenérgicos alfa 2 , Antagonistas de Receptores Adrenérgicos alfa 2 , Animales , Convulsivantes/administración & dosificación , Convulsivantes/efectos adversos , Dihidropiridinas/administración & dosificación , Antagonistas de Receptores de GABA-A , Idazoxan/administración & dosificación , Infusiones Intravenosas , Inyecciones Intraperitoneales , Masculino , Ratones , Ratones Endogámicos CBA , Picrotoxina/administración & dosificación , Picrotoxina/efectos adversos , Convulsiones/inducido químicamente , Estrés Fisiológico/metabolismo
13.
Ann N Y Acad Sci ; 814: 209-25, 1997 Apr 24.
Artículo en Inglés | MEDLINE | ID: mdl-9160973

RESUMEN

Activin as a neurodifferentiation factor. Our studies of neurotransmitter expression have focused on the expression of neuropeptide transmitters in the avian ciliary ganglion (CG) and have examined the influence of choroidal vascular smooth muscle cells in regulating the differential expression of somatostatin in the CG. In these activities we have identified activin A as a potential target-derived neurodifferentiation factor that can stimulate somatostatin expression in cultured CG neurons. In cultured CG neurons, activin can stimulate the expression of somatostatin in choroid neurons, the pattern of neurotransmitter expression found in vivo, and in the ciliary neurons that would normally not express somatostatin. In vivo, mRNA transcripts of the cActR-IIA appear to be expressed by both choroid and ciliary CG neurons. This suggests that activin might serve as an instructive factor in controlling neuropeptide phenotype. For activin to serve as an instructive factor requires that activin be produced by choroid smooth-muscle target cells. Indeed, activin mRNA and activin-like immunoreactivity are found in choroid cells, in vitro. However, the lack of somatostatin expression by ciliary neurons suggests that activin is not produced by their targets, the iris and ciliary body. This simple view is countered by the observation that activin A mRNA is also present in the iris and activin-like immunoreactivity is detectable in the iris and ciliary body. Instead, the production of the specific activin inhibitor follistatin in the iris and ciliary body is likely to limit the availability of activin to only those neurites innervating the choroid layer, thus accounting for the differential expression of somatostatin in only the choroid CG neurons. This somewhat more complicated arrangement is similar to the mechanism thought to be employed for primary induction during frog embryogenesis. The observations reviewed here are all consistent with the hypothesized role for activin as a molecule whose availability to neurites in the target regulates neurotransmitter expression. Additional in vivo perturbation experiments are needed to further examine this hypothesis; nevertheless, activin appears as a strong candidate for a target-derived neurotransmitter differentiation factor. Activin's potential roles in differentiation: A wide variety of biological effects have been ascribed to activin. Initially identified and purified as a gonadal hormone stimulating the production and release of FSH from the pituitary, activin is also implicated in the stimulation of erythroid differentiation, as a modulator of follicular granulosa cell differentiation, as a mesodermalizing factor in both amphibian and avian early development, and as a component in establishing left-right axial patterning in the chicken embryo. Activin has also been found to be a survival factor for several neuronal cell lines and for rat embryonic neural retina cells in culture. However, activin is not a survival factor for chicken CG neurons in culture. Our observation that activin may play a function in target-derived control of neuropeptide expression adds yet another aspect to the list of its potential biological functions. In addition, activin shares regions of amino acid sequence identity with members of the TGF-beta superfamily, which includes the TGF-betas, Mullerian inhibitory substance, Drosophila decapentaplegic gene product, dorsalin, bone morphogenetic proteins, inhibin, and glial-derived neurotrophic factor. Interestingly, these are all factors that have effects upon cellular differentiation. Effects of activin on other neurons. Activin A--as well as two other TGF-beta superfamily members, BMP-2 and BMP-6--has been shown to induce expression of mRNAs for several neuropeptides in cultured rat sympathetic neurons. In addition, activin A induces ChAT mRNA in cultured sympathetic neurons. (ABSTRACT TRUNCATED)


Asunto(s)
Ganglios Parasimpáticos/metabolismo , Somatostatina/metabolismo , Activinas , Animales , Aves , Células Cultivadas , Plexo Coroideo/metabolismo , Ganglios Parasimpáticos/crecimiento & desarrollo , Hibridación in Situ , Inhibinas/genética , Inhibinas/metabolismo , Neuronas/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas
14.
J Neurol ; 225(3): 175-82, 1981.
Artículo en Inglés | MEDLINE | ID: mdl-6167682

RESUMEN

Among 234 haemophiliacs (A and B) treated between 1948 and 1975 at the First Medical Clinic of the University of Vienna, 25 (10.8%) with 36 peripheral nerve lesions have been observed. This amounts to 15.3% or 2.4 lesions within 100 observation years. The average age of the patients at the time of development of lesion was 26.4 years. Correlations between severity of haemophilia and frequency of occurrence of lesions were found. Patients with mild haemophilia did not show peripheral nerve disturbances. The numbers of times individual nerves were affected are as follows: maxillary (1), radial (2), medial (6), ulnar (4), obturator (1), lateral cutaneous nerve of thigh (1), femoral (12), including lesions of the 2nd and 3rd lumbar roots, sciatic (6), including lesions of te 5th lumbar and the 1st sacral roots, peroneal (3), and tibial (1). In 1978, 11 patients who previously had sustained 16 peripheral lesions were reexamined. Of these, 10 had fully recovered, 4 showed some persisting sensory disturbances, and 2 were unchanged. Motor nerve conduction velocity, distal latency and compound nerve action potentials were systematically examined in 11 cases on both sides of the body. In contrast to our expectations, no signs of subclinical peripheral nerve lesions were found. The comparability of the presence and previous results is discussed.


Asunto(s)
Hemofilia A/complicaciones , Hemofilia B/complicaciones , Enfermedades del Sistema Nervioso Periférico/etiología , Adolescente , Adulto , Factores de Edad , Niño , Estimulación Eléctrica , Hemorragia/complicaciones , Humanos , Nervio Mediano/fisiopatología , Persona de Mediana Edad , Conducción Nerviosa , Nervio Peroneo/fisiopatología , Pronóstico , Nervio Cubital/fisiopatología
15.
Inflammation ; 14(2): 205-16, 1990 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-2108925

RESUMEN

We investigated the dynamics of the acute-phase response (APR) and osteoblast trabecular surface in rats with subcutaneous inflammation provoked by magnesium silicate (talc). The first visible indicator of the APR was a rapid and profound hypozincemia, paralleled by a decrease in metaphyseal trabecular surfaces covered with osteoblasts in long bones. Both the intensity of serum APR and the decrease in osteoblast trabecular surface were directly proportional to the number of granulomas. Alterations in bone metabolism were specific for the inflammation, whereas mild hypozincemia and decrease in mononuclear and increase in polymorphonuclear peripheral white blood cell fractions developed in animals pair-fed with rats bearing two or four granulomas. Rats with talc granulomatosis had high serum ACTH and corticosterone levels, but neither adrenalectomy nor high doses of hydrocortisone could revert bone alterations in talc-injected animals. Glucocorticoids were necessary for the development of hypozincemia and hypercupremia seen in talc granulomatosis, as well as for normal bone metabolism. Inhibition of prostaglandin synthesis had no effect on bone alterations and serum APR in rats bearing talc-induced granulomas. We conclude that the decrease in bone formation constitutes an important aspect of the host acute-phase response in a rat model of talc granulomatosis.


Asunto(s)
Reacción de Fase Aguda/metabolismo , Huesos/metabolismo , Granuloma/etiología , Inflamación/metabolismo , Osteoblastos/metabolismo , Talco/toxicidad , Reacción de Fase Aguda/fisiopatología , Animales , Femenino , Glucocorticoides/fisiología , Granuloma/metabolismo , Granuloma/fisiopatología , Ratas
16.
Biol Trace Elem Res ; 29(2): 165-73, 1991 May.
Artículo en Inglés | MEDLINE | ID: mdl-1713473

RESUMEN

Subcutaneous inflammation induced by magnesium silicate (talc) leads to the suppression of bone elongation, osteoblast insufficiency, and subsequent bone loss in rats. Since bone and immunological changes in talc granulomatosis are similar to those observed in zinc deficiency, we investigated the kinetics of zinc tissue distribution and the effects of zinc supplementation on the development of bone loss in rats with talc-induced inflammation. Decrease in serum zinc concentration was observed between 5 and 15 h in rats with talc granulomatosis. It was paralleled by the accumulation of zinc in the liver and rapid disappearance of osteoblasts from the trabecular bone surfaces. However, talc-injected rats supplemented parenterally and orally with zinc sulfate exhibited a decrease in osteoblast trabecular surface comparable to that of unsupplemented rats bearing granulomas despite normalized serum zinc concentrations. Zinc supplementation slightly increased osteoblast trabecular surface in all supplemented groups, but this effect was not significant. We conclude that zinc is the earliest indicator of the acute-phase response in rats with talc granulomatosis. Although zinc appears to be important for the normal function of bone cells, there is no causative relationship between acute zinc deficiency and decreased osteoblast number and activity in rats with talc granulomatosis.


Asunto(s)
Reacción de Fase Aguda/metabolismo , Resorción Ósea/metabolismo , Granuloma/metabolismo , Zinc/deficiencia , Reacción de Fase Aguda/etiología , Reacción de Fase Aguda/patología , Análisis de Varianza , Animales , Resorción Ósea/etiología , Femenino , Granuloma/etiología , Granuloma/patología , Hígado/metabolismo , Ratas , Ratas Endogámicas F344 , Talco , Tibia/patología , Zinc/metabolismo
17.
Diabetologia ; 50(3): 634-42, 2007 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-17242917

RESUMEN

AIMS/HYPOTHESIS: Adiponectin is an adipocyte-derived secretory factor that is specifically produced in adipocytes. It exerts effects on energy homeostasis via peripheral and central mechanisms. However, it is not clear whether adiponectin crosses the blood-brain barrier in humans. In serum, adiponectin circulates in several different complexes, each of which has distinct functions. Here, we wanted to test whether adiponectin can be found in human cerebrospinal fluid (CSF) and whether specific adiponectin complexes are enriched in CSF compared with peripheral serum samples. We also wanted to establish whether there is a sex-related difference with regard to the distribution of adiponectin oligomers in CSF. MATERIALS AND METHODS: We studied 22 subjects (11 men, 11 women) in this study. Their average BMI was 28.0+/-4.7 kg/m2; average age was 70+/-7 years. RESULTS: Analysis of total adiponectin revealed that adiponectin protein is present in human CSF at approximately 0.1% of serum concentration. The distribution of adiponectin oligomers differs considerably in CSF from that of serum within matched samples from the same patients. Only the adiponectin trimeric and low-molecular-mass hexameric complexes are found in CSF, with a bias towards the trimeric form in most patients. Male subjects have a higher CSF:serum ratio of total adiponectin (p<0.05; n=20) and have slightly higher trimer levels in serum and CSF than female subjects. CONCLUSIONS/INTERPRETATION: We conclude that the adiponectin trimer is the predominant oligomer in human CSF.


Asunto(s)
Adiponectina/líquido cefalorraquídeo , Adiponectina/sangre , Anciano , Anciano de 80 o más Años , Índice de Masa Corporal , Femenino , Humanos , Masculino , Persona de Mediana Edad , Peso Molecular , Población Blanca
18.
J Neurobiol ; 32(1): 33-44, 1997 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-8989661

RESUMEN

Previous studies have suggested that activin may serve as a neurodifferentiation factor regulating somatostatin expression in neurons of the avian ciliary ganglion (CG). As one aspect of examining the role of activin in CG development, we inquired whether any of the known activin receptors are expressed by developing CG neurons in vivo. In addition, we examined whether activin A mRNA is expressed in the choroid layer and iris of the chicken eye. Oligonucleotide primers were designed for the chicken activin receptor type IIA (cActR-IIA), type IIB (cActR-IIB), and activin A. In reverse-transcription-polymerase chain reaction (rtPCR), an appropriately sized product was amplified from CG cDNA using primers to the cActR-IIA but not the cActR-IIB. Sequencing confirmed the identity of the PCR product as a fragment of the cActR-IIA. It thus appears that mRNA for the type IIA but not the type IIB activin receptor is expressed in the chicken CG. An antisense strand digoxigenin-labeled riboprobe complimentary to a 358-bp portion of the cActR-IIA kinase region hybridized to cells within cryostat sections of embryonic CG. From E6.5-E18, hybridization of this probe appears to be specific for cells with a neuronal morphology. Using rtPCR with activin A-specific primers we detected activin mRNA in the choroid layer of E14 and E19 eyes, and from the iris at E14. Our results are consistent with a role for activin as a neurodifferentiation factor in vivo, and imply that within the CG, the cActR-IIA is specifically expressed by neurons, and that activin A is expressed in the targets of these neurons.


Asunto(s)
Cuerpo Ciliar/citología , Neuronas/química , Receptores de Factores de Crecimiento/genética , Receptores de Activinas , Activinas , Animales , Embrión de Pollo , Coroides/química , Coroides/inervación , Digoxigenina , Regulación del Desarrollo de la Expresión Génica/fisiología , Regulación Enzimológica de la Expresión Génica/fisiología , Sustancias de Crecimiento/genética , Hibridación in Situ , Inhibinas/genética , Iris/química , Iris/inervación , Neuronas/fisiología , Reacción en Cadena de la Polimerasa , Proteínas Serina-Treonina Quinasas/genética , Sondas ARN , ARN Mensajero/metabolismo
19.
Opt Lett ; 23(13): 1001-3, 1998 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-18087409

RESUMEN

We report the observation of high-intensity solitons in a bulk strontium barium niobate crystal. The solitons are observed by use of 8-ns optical pulses with optical intensities greater than 100 MW/cm(2). Each soliton forms and attains its minimum width after roughly ten pulses and reaches e(-1) of the steady-state width after the first pulse. We find good agreement between experimental observations and theoretical predictions for the soliton existence curve.

20.
Infect Immun ; 43(3): 1094-6, 1984 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-6698604

RESUMEN

Mice fed a diet high in cholesterol, lard, and sucrose were shown to exhibit an impairment of specific immunity to Listeria monocytogenes. Whereas titers of L. monocytogenes in livers of normal mice decreased rapidly after 6 days of infection, L. monocytogenes persisted in livers of diet-fed mice. Adoptive transfer experiments indicated that L. monocytogenes-immune spleen cells are generated in diet-fed mice. However, the function of immune spleen cells from donors of either nutritional status was impaired in diet-fed recipients. The results indicate that the site(s) of impairment of specific immunity to L. monocytogenes in diet-fed mice occurs at a stage beyond the generation of immune T-cells.


Asunto(s)
Colesterol en la Dieta/efectos adversos , Síndromes de Inmunodeficiencia/inmunología , Listeriosis/complicaciones , Animales , Inmunidad Celular , Inmunización Pasiva , Síndromes de Inmunodeficiencia/etiología , Síndromes de Inmunodeficiencia/terapia , Hepatopatías/microbiología , Ratones , Ratones Endogámicos C57BL , Bazo/citología
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