Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 57
Filter
Add more filters

Country/Region as subject
Publication year range
1.
Mol Psychiatry ; 16(1): 97-107, 2011 Jan.
Article in English | MEDLINE | ID: mdl-19786962

ABSTRACT

Dyslexia is one of the most common learning disorders affecting about 5% of all school-aged children. It has been shown that event-related potential measurements reveal differences between dyslexic children and age-matched controls. This holds particularly true for mismatch negativity (MMN), which reflects automatic speech deviance processing and is altered in dyslexic children. We performed a whole-genome association analysis in 200 dyslexic children, focusing on MMN measurements. We identified rs4234898, a marker located on chromosome 4q32.1, to be significantly associated with the late MMN component. This association could be replicated in an independent second sample of 186 dyslexic children, reaching genome-wide significance in the combined sample (P = 5.14e-08). We also found an association between the late MMN component and a two-marker haplotype of rs4234898 and rs11100040, one of its neighboring single nucleotide polymorphisms (SNPs). In the combined sample, this marker combination withstands correction for multiple testing (P = 6.71e-08). Both SNPs lie in a region devoid of any protein-coding genes; however, they both show significant association with mRNA-expression levels of SLC2A3 on chromosome 12, the predominant facilitative glucose transporter in neurons. Our results suggest a possible trans-regulation effect on SLC2A3, which might lead to glucose deficits in dyslexic children and could explain their attenuated MMN in passive listening tasks.


Subject(s)
Chromosomes, Human, Pair 4 , Dyslexia/genetics , Evoked Potentials, Auditory/genetics , Glucose Transporter Type 3/genetics , Speech Perception/genetics , Adolescent , Case-Control Studies , Child , Contingent Negative Variation/genetics , Discrimination, Psychological/physiology , Female , Genome-Wide Association Study , Humans , Male , Reference Values , Young Adult
2.
Osteoporos Int ; 19(12): 1759-67, 2008 Dec.
Article in English | MEDLINE | ID: mdl-18414963

ABSTRACT

UNLABELLED: The genetic contribution to age-related bone loss is not well understood. We estimated that genes accounted for 25-45% of variation in 5-year change in bone mineral density in men and women. An autosome-wide linkage scan yielded no significant evidence for chromosomal regions implicated in bone loss. INTRODUCTION: The contribution of genetics to acquisition of peak bone mass is well documented, but little is known about the influence of genes on subsequent bone loss with age. We therefore measured 5-year change in bone mineral density (BMD) in 300 Mexican Americans (>45 years of age) from the San Antonio Family Osteoporosis Study to identify genetic factors influencing bone loss. METHODS: Annualized change in BMD was calculated from measurements taken 5.5 years apart. Heritability (h(2)) of BMD change was estimated using variance components methods and autosome-wide linkage analysis was carried out using 460 microsatellite markers at a mean 7.6 cM interval density. RESULTS: Rate of BMD change was heritable at the forearm (h(2) = 0.31, p = 0.021), hip (h(2) = 0.44, p = 0.017), spine (h(2) = 0.42, p = 0.005), but not whole body (h(2) = 0.18, p = 0.123). Covariates associated with rapid bone loss (advanced age, baseline BMD, female sex, low baseline weight, postmenopausal status, and interim weight loss) accounted for 10% to 28% of trait variation. No significant evidence of linkage was observed at any skeletal site. CONCLUSIONS: This is one of the first studies to report significant heritability of BMD change for weight-bearing and non-weight-bearing bones in an unselected population and the first linkage scan for change in BMD.


Subject(s)
Bone Density/genetics , Mexican Americans/genetics , Osteoporosis/genetics , Absorptiometry, Photon , Anthropometry , Bone Density/physiology , Female , Genetic Linkage , Genetic Predisposition to Disease , Genotype , Humans , Male , Microsatellite Repeats/genetics , Middle Aged , Osteoporosis/physiopathology , Texas/ethnology , Weight-Bearing/physiology
3.
J Clin Invest ; 105(12): 1833-8, 2000 Jun.
Article in English | MEDLINE | ID: mdl-10862799

ABSTRACT

Paget's disease is characterized by highly localized areas of increased osteoclast (OCL) activity. This suggests that the microenvironment in pagetic lesions is highly osteoclastogenic, or that OCL precursors in these lesions are hyperresponsive to osteoclastogenic factors (or both). To examine these possibilities, we compared RANK ligand (RANKL) mRNA expression in a marrow stromal cell line developed from a pagetic lesion (PSV10) with that in a normal stromal cell line (Saka), and expression in marrow samples from affected bones of Paget's patients with that in normal marrow. RANKL mRNA was increased in PSV10 cells and pagetic marrow compared with Saka cells and normal marrow, and was also increased in marrow from affected bones compared with uninvolved bones from Paget's patients. Furthermore, pagetic marrow cells formed OCLs at much lower RANKL concentrations than did normal marrow. Anti-IL-6 decreased the RANKL responsivity of pagetic marrow to normal levels, whereas addition of IL-6 to normal marrow enhanced RANKL responsivity. Thus, RANKL expression and responsivity is increased in pagetic lesions, in part mediated by IL-6. These data suggest that the combination of enhanced expression of RANKL in affected bones and increased RANKL sensitivity of pagetic OCL precursors may contribute to the elevated numbers of OCLs in Paget's disease.


Subject(s)
Bone Marrow Cells/metabolism , Carrier Proteins/genetics , Gene Expression Regulation , Membrane Glycoproteins/genetics , Osteitis Deformans/metabolism , Antibodies/pharmacology , Bone Marrow Cells/cytology , Bone Marrow Cells/pathology , Bone and Bones/cytology , Bone and Bones/metabolism , Bone and Bones/pathology , Cells, Cultured , Humans , Interleukin-6/antagonists & inhibitors , Interleukin-6/physiology , Osteitis Deformans/pathology , Osteoclasts/metabolism , RANK Ligand , RNA, Messenger/genetics , Receptor Activator of Nuclear Factor-kappa B , Reference Values , Stromal Cells/cytology , Stromal Cells/metabolism , Stromal Cells/pathology , Transcription, Genetic
4.
J Clin Invest ; 102(5): 929-37, 1998 Sep 01.
Article in English | MEDLINE | ID: mdl-9727061

ABSTRACT

We have used adenoviral-mediated gene transfer of a constitutively active (V12rac1) and dominant negative (N17rac1) isoform of rac1 to assess the role of this small GTPase in cardiac myocyte hypertrophy. Expression of V12rac1 in neonatal cardiac myocytes results in sarcomeric reorganization and an increase in cell size that is indistinguishable from ligand-stimulated hypertrophy. In addition, V12rac1 expression leads to an increase in atrial natriuretic peptide secretion. In contrast, expression of N17rac1, but not a truncated form of Raf-1, attenuated the morphological hypertrophy associated with phenylephrine stimulation. Consistent with the observed effects on morphology, expression of V12rac1 resulted in an increase in new protein synthesis, while N17rac1 expression inhibited phenylephrine-induced leucine incorporation. These results suggest rac1 is an essential element of the signaling pathway leading to cardiac myocyte hypertrophy.


Subject(s)
Cardiomegaly/physiopathology , GTP-Binding Proteins/physiology , Myocardium/cytology , Signal Transduction/physiology , Adenoviridae/genetics , Animals , Animals, Newborn , Atrial Natriuretic Factor/metabolism , Calcium-Calmodulin-Dependent Protein Kinases/analysis , Cell Size/physiology , Cells, Cultured , Fluorescent Antibody Technique , GTP Phosphohydrolases/physiology , Gene Expression Regulation/physiology , Gene Transfer Techniques , Phenylephrine/pharmacology , Protein Biosynthesis , Proto-Oncogene Proteins c-raf/physiology , Rats , Rats, Sprague-Dawley , Sarcomeres/ultrastructure , rac GTP-Binding Proteins
5.
J Clin Invest ; 101(9): 1821-6, 1998 May 01.
Article in English | MEDLINE | ID: mdl-9576744

ABSTRACT

We demonstrate that adenoviral-mediated gene transfer of a dominant negative rac1 gene product (N17rac1) inhibits the intracellular burst of reactive oxygen species (ROS) that occurs after reoxygenation of vascular smooth muscle cells. In contrast, expression of a dominant negative ras gene (N17ras) had no effect. Challenge of control cells and cells expressing N17rac1 with a direct oxidant stress produced an equivalent increase in intracellular ROS levels and subsequent cell death. This suggests that N17rac1 expression appears to block production of harmful oxygen radicals and does not act directly or indirectly to scavenge ROS generated during reoxygenation. Expression of N17rac1 results in protection from hypoxia/reoxygenation-induced cell death in a variety of cell types including vascular smooth muscle cells, fibroblasts, endothelial cells, and ventricular myocytes. These results suggest that reoxygenation injury requires the activation of rac proteins, and that inhibition of rac-dependent pathways may be a useful strategy for the prevention of reperfusion injury in ischemic tissues.


Subject(s)
GTP-Binding Proteins/antagonists & inhibitors , Muscle, Smooth, Vascular/drug effects , Oxygen/pharmacology , Aerobiosis , Anaerobiosis , Animals , Aorta/cytology , Cell Death/drug effects , Cells, Cultured , Free Radical Scavengers , GTP-Binding Proteins/genetics , Humans , Muscle, Smooth, Vascular/pathology , Rats , Reactive Oxygen Species/metabolism , Recombinant Proteins/antagonists & inhibitors , Reperfusion Injury/prevention & control , Signal Transduction , Umbilical Veins/cytology , rac GTP-Binding Proteins , ras Proteins/metabolism
6.
Mol Cell Biol ; 9(11): 5143-53, 1989 Nov.
Article in English | MEDLINE | ID: mdl-2601713

ABSTRACT

We have identified a cellular enhancer-binding protein, present in nuclear extracts prepared from human and rodent cells, that binds to the adenovirus E1A enhancer element I sequence. The factor has been termed EF-1A, for enhancer-binding factor to the E1A core motif. EF-1A was found to bind to two adjacent, related sequence motifs in the E1A enhancer region (termed sites A and B). The binding of EF-1A to these adjacent sites, or to synthetic dimerized sites of either motif, was cooperative. The cooperative binding of EF-1A to these sites was not subject to strict spacing constraints. EF-1A also bound to related sequences upstream of the E1A enhancer region and in the polyomavirus and adenovirus E4 enhancer regions. The EF-1A-binding region in the E1A enhancer stimulated expression of a linked gene in human 293 cells when multimerized. Based on the contact sites for EF-1A binding determined by chemical interference assays, this protein appears to be distinct from any previously characterized nuclear binding protein.


Subject(s)
Adenoviridae/genetics , DNA-Binding Proteins/genetics , Enhancer Elements, Genetic , Transcription, Genetic , Animals , Base Sequence , Binding Sites , Binding, Competitive , Electrophoresis, Polyacrylamide Gel , HeLa Cells , Humans , Molecular Sequence Data , Mutation
7.
Mol Cell Biol ; 15(8): 4260-71, 1995 Aug.
Article in English | MEDLINE | ID: mdl-7623820

ABSTRACT

T-cell activation requires two different signals. The T-cell receptor's recognition of a specific antigen on antigen-presenting cells provides one, and the second signal comes from costimulatory molecules such as CD28. In contrast, T cells that are stimulated with antigen in the absence of the CD28 costimulatory signal can become anergic (nonresponsive). The CD28 response element (CD28RE) has been identified as the DNA element mediating interleukin 2 (IL-2) gene activation by CD28 costimulation. Our previous work demonstrates that the Rel/NF-kappa B family proteins c-Rel, RelA (p65), and NFKB1 (p50) are involved in the complex that binds to the CD28RE. We also showed that c-Rel, but not NFKB1 (p50), can bind to the CD28RE and activate CD28RE-driven transcription in cotransfection assays. However, the role of RelA (p65) in CD28 signaling has not yet been addressed. We provide evidence that RelA (p65) itself bound directly to the CD28RE of the IL-2 promoter and other lymphokine promoters. In addition, RelA (p65) was a potent transcriptional activator of the CD28RE in vivo. We show that a RelA (p65)-c-Rel heterodimer bound to the CD28RE and synergistically activated the CD28RE enhancer activity. We also demonstrate that activated Raf-1 kinase synergized with RelA (p65) in activating the CD28RE enhancer activity. Interestingly, a soluble anti-CD28 monoclonal antibody alone, in the absence of other stimuli, also synergized with RelA (p65) in activating the CD28RE. Furthermore, we show that RelA (p65) activated expression of the wild-type IL-2 promoter but not the CD28RE-mutated IL-2 promoter. A combination of RelA (p65) and NFKB1 (p50) also activated the IL-2 promoter through the CD28RE site. These results demonstrate the functional regulation of the CD28RE, within the IL-2 promoter, by Rel/NF-kappa B transcription factors.


Subject(s)
CD28 Antigens/metabolism , Gene Expression Regulation , I-kappa B Proteins , Interleukin-2/genetics , NF-kappa B/metabolism , Promoter Regions, Genetic/genetics , T-Lymphocytes/physiology , Base Sequence , DNA-Binding Proteins/pharmacology , Enhancer Elements, Genetic , Granulocyte-Macrophage Colony-Stimulating Factor/genetics , Humans , Interferon-gamma/genetics , Interleukin-2/biosynthesis , Interleukin-3/genetics , Lymphocyte Activation , Molecular Sequence Data , NF-KappaB Inhibitor alpha , NF-kappa B/genetics , Protein Binding , Protein Serine-Threonine Kinases/metabolism , Proto-Oncogene Proteins/metabolism , Proto-Oncogene Proteins c-raf , Recombinant Proteins/metabolism , Signal Transduction , Transcription Factor RelA , Transcription, Genetic/drug effects , Transcriptional Activation
8.
Oncogene ; 8(9): 2443-8, 1993 Sep.
Article in English | MEDLINE | ID: mdl-8361757

ABSTRACT

We examined the effect of overexpression of growth factor-regulated second messenger enzymes, alone and in combination, on transformation of NIH3T3 cells. Signal transducers included phospholipase C-gamma (PLC-gamma), protein kinase C-gamma (PKC-gamma), and two proto-oncogenes, c-H-ras and c-raf-1. Three of these proteins, PLC-gamma, PKC-gamma and Raf-1, did not transform NIH3T3 cells alone or in combination. c-H-ras, which under its own promoter control has low transforming activity, also did not cooperate with PLC-gamma or PKC-gamma. In contrast, the combination of normal or oncogenic p21 H-Ras with the Raf-1 kinase dramatically increased transformation efficiency. The level of Ras protein required for transformation was reduced in Raf-1 co-transfectants, implying that, at low levels of p21 Ras, p74 Raf-1 is rate limiting. As transformation by Ras depends on jun-mediated transcriptional events, we also examined H-ras and c-raf-1 cooperation in transcriptional transactivation of TPA-responsive element (TRE)-dependent reporters. Like the H-ras/c-raf-1 cooperation in transformation, we observed this synergistic stimulation of TRE-dependent transcription. This pathway for transformation and transcriptional activation by increased levels of normal Ras and Raf may be important in tumors that show overexpression but lack mutationally activated forms of these two proto-oncogenes.


Subject(s)
Cell Transformation, Neoplastic/genetics , Genes, ras , Proto-Oncogene Proteins p21(ras)/metabolism , Proto-Oncogene Proteins/genetics , 3T3 Cells , Animals , Gene Expression , Growth Substances/physiology , In Vitro Techniques , Mice , Protein Kinase C/physiology , Protein-Tyrosine Kinases/metabolism , Proto-Oncogene Proteins c-raf , Second Messenger Systems , Transcription, Genetic , Transfection , Type C Phospholipases/physiology
9.
Oncogene ; 7(9): 1867-73, 1992 Sep.
Article in English | MEDLINE | ID: mdl-1386920

ABSTRACT

A dominant negative mutant of Ras, M17 Ras, was used to study the role of Ras in receptor coupling of Raf-1 and B-Raf protein serine/threonine kinases (PSKs). We found that mutant Ras blocks serum- and 12-O-tetradecanoyl phorbol 13-acetate-induced activation of Raf-1 kinase in NIH3T3 cells and Raf-1 as well as B-Raf PSK stimulation by nerve growth factor (NGF) in PC12 pheochromocytoma cells. Mitogen stimulation of Raf kinase was measured by determination of Raf hyperphosphorylation and activity towards exogenous substrates and both of these events were inhibited in cells expressing M17 Ras. In contrast, tyrosine phosphorylation of a direct substrate of activated tyrosine kinase receptors, phospholipase C-gamma 1 (PLC-gamma 1), was unaffected. These data indicate that tyrosine phosphorylation of PLC-gamma 1 is not sufficient for growth induction in NIH3T3 cells and that Ras mediates signal transfer from activated membrane receptors to Raf kinases in the cytosol. As activated Raf induced differentiation in PC12 cells expressing M17 Ras we conclude that Raf kinase activation may be sufficient to account for this aspect of NGF function.


Subject(s)
Genes, ras , Protein Kinase C/physiology , Protein Kinases/physiology , Proto-Oncogene Proteins/physiology , 3T3 Cells , Amino Acid Sequence , Animals , Blood Physiological Phenomena , Cytosol/metabolism , Dexamethasone/pharmacology , ErbB Receptors/physiology , Mice , Molecular Sequence Data , Nerve Growth Factors/pharmacology , Phosphorylation , Protein Serine-Threonine Kinases , Protein-Tyrosine Kinases/metabolism , Proto-Oncogene Proteins c-raf , Receptor, Macrophage Colony-Stimulating Factor/physiology , Tetradecanoylphorbol Acetate/pharmacology
10.
Curr Opin Biotechnol ; 8(5): 583-9, 1997 Oct.
Article in English | MEDLINE | ID: mdl-9353227

ABSTRACT

Adenoviruses began to be developed into highly effective gene expression vectors in the early 1980s. Recently, the increased interest in utilizing this transfer system in vivo has posed new problems for heterologous gene-transfer, spurring a renewed effort in the field of vector development toward solving the structural, immunological and targeting problems posed by gene therapy applications.


Subject(s)
Adenoviridae/genetics , Genetic Vectors , Recombinant Proteins/biosynthesis , Transfection/methods , Animals , Antibody Formation , Cytokines/biosynthesis , Genetic Therapy/methods , Humans , Immunity, Cellular , Immunotherapy/methods
11.
Mol Endocrinol ; 10(1): 35-44, 1996 Jan.
Article in English | MEDLINE | ID: mdl-8838143

ABSTRACT

Treatment of GT1-7 neuronal cells with the phorbol ester, 12-O-tetradecanoyl phorbol 13-acetate (TPA), inhibits GnRH gene transcription. The present studies investigated the role of AP-1 (Fos and Jun) in this repression. Treatment of cells with TPA increased c-fos mRNA 20-fold with only a 2-fold increase in c-jun mRNA levels. In transient transfection studies, a luciferase expression vector containing fragments of the 5'-flanking DNA of the rat GnRH (rGnRH) promoter was cotransfected with Fos and Jun expression vectors to mimic the effects of TPA. A dose-dependent decrease in reporter activity was noted with increasing amounts of Fos but not with Jun overexpression. Deletion analysis mapped the region that mediates repression by AP-1 to the area between -126 and -73 base pairs (bp) of the rGnRH 5'-flanking region: the same area that mediates TPA-induced repression and contains an imperfect TPA response element sequence at -99. Gel retardation assays, however, showed that a DNA fragment from -111 to -73 of the rGnRH promoter does not directly interact with Fos in GT1-7 extracts. Coexpression of Fos proteins with mutations in the DNA-binding region, the dimerization domain, or carboxy terminus partially blocked inhibition of rGnRH promoter activity. These data support a novel mechanism of AP-1 repression of GnRH transcription that is mediated by Fos interaction with other protein(s) that directly bind to the proximal rGnRH promoter.


Subject(s)
Genes, fos/genetics , Genes, jun/genetics , Gonadotropin-Releasing Hormone/genetics , Promoter Regions, Genetic , Tetradecanoylphorbol Acetate/pharmacology , Transcription, Genetic/drug effects , Animals , Base Sequence , Binding Sites , DNA/metabolism , Gene Expression , Leucine Zippers , Luciferases/genetics , Molecular Sequence Data , RNA, Messenger/metabolism , Rats , Transcription Factor AP-1/pharmacology , Transfection
12.
Hum Gene Ther ; 11(1): 139-49, 2000 Jan 01.
Article in English | MEDLINE | ID: mdl-10646646

ABSTRACT

Adenovirus vectors expressing gene products that can induce apoptosis have potential utility in gene therapy applications ranging from the treatment of proliferative diseases to transplantation. However, adenovirus vectors carrying proapoptotic gene products are difficult to produce, as the apoptotic environment is not conducive to adenovirus gene expression and replication. Production of AdFasL/G, an adenovirus vector that expresses high levels of Fas ligand, was severely reduced in the 293 packaging cell line. Increased yields of AdFasL/G were achieved by inclusion of peptide-based caspase inhibitors in the growth medium. However, use of these inhibitors for large-scale production would be difficult and expensive. A screen for gene products that increase the yield of AdFasL/G in 293 cells revealed that the poxvirus serpin CrmA and the adenovirus 14.7K product were able to increase virus yields significantly. Apoptosis induced by AdFasL/G was attenuated in 293CrmA cell lines and virus titers were increased dramatically. However, serial passage of AdFasL/G on 293CrmA cells resulted in the generation of replication-competent adenovirus. To resolve this problem, the CrmA gene was introduced into AE25 cells, an E1-complementing cell line that has limited sequence identity with the vectors. AdFasL/G titers were increased 100-fold on AE25CrmA cells relative to the AE25 cells and RCA contamination was not detectable. In addition, adenovirus vectors that express FADD, caspase 8, and Fas/APO1 were produced efficiently in AE25CrmA and 293CrmA.


Subject(s)
Adenoviridae/genetics , Apoptosis/genetics , Genetic Vectors , Transgenes , Apoptosis/drug effects , Caspase Inhibitors , Cysteine Proteinase Inhibitors/pharmacology , Humans , In Situ Nick-End Labeling , Tumor Cells, Cultured
13.
Hum Gene Ther ; 12(12): 1499-512, 2001 Aug 10.
Article in English | MEDLINE | ID: mdl-11506693

ABSTRACT

Proapoptotic adenovirus vectors offer great promise for the treatment of cancer and nonmalignant conditions. Benign prostate hyperplasia (BPH) is a common nonmalignant enlargement of the prostate that involves epithelial, stromal, and smooth muscle components of the gland. We tested the hypothesis that an adenovirus vector expressing Fas ligand can be used to induce apoptosis in the prostate. We analyzed the efficiency of transduction and apoptosis induction in primary cultures of human prostate cells after adenovirus-mediated gene transfer. Efficient transduction was observed in primary prostate epithelial cells. Stromal and smooth muscle cells were more difficult to transduce, as no coxsackie-adenovirus receptor (CAR) expression was detectable on these cells. However, transduction was achieved in these cells when the multiplicity of infection was increased to 100 focal-forming units per cell, or when the vectors were delivered as calcium phosphate precipitates. Infection of all three primary prostate cell types with an adenovirus vector that expresses Fas ligand (AdFasL/G) resulted in rapid apoptosis. Direct injection of the rat prostate with an adenovirus vector carrying luciferase resulted in substantial luciferase expression. TUNEL analysis demonstrated that AdFasL/G administration induced low-level apoptosis in prostatic epithelial cells throughout the gland. As a first step toward enhancing the efficiency of prostate transduction in vivo, we tested an adenovirus vector that was engineered to have an expanded tropism. This vector, AdZ.F2K(pK7), was 10- to 500-fold more efficient than unmodified vectors in transducing prostate epithelial, smooth muscle, and stromal cells in culture. Moreover, AdZ.F2K(pK7) was more efficient than an unmodified vector at transducing the rat prostate in vivo, although the effect was dose dependent.


Subject(s)
Adenoviridae/genetics , Apoptosis , Genetic Vectors , Hyperplasia/therapy , Prostate/metabolism , Transduction, Genetic , Animals , Calcium Phosphates/metabolism , Cells, Cultured , Dose-Response Relationship, Drug , Epithelial Cells/metabolism , Fas Ligand Protein , Flow Cytometry , Genetic Vectors/genetics , Humans , In Situ Nick-End Labeling , Luciferases/metabolism , Male , Membrane Glycoproteins/genetics , Muscle, Smooth/cytology , Muscle, Smooth/metabolism , Poly(ADP-ribose) Polymerases/metabolism , Prostate/pathology , Rats , Tumor Cells, Cultured , beta-Galactosidase/metabolism
14.
Endocrinology ; 131(6): 2552-8, 1992 Dec.
Article in English | MEDLINE | ID: mdl-1446598

ABSTRACT

The effects of the phorbol ester 12-O-tetradecanoyl phorbol 13-acetate (TPA), an activator of protein kinase C (PKC), and the PKC inhibitor staurosporine on GnRH secretion and mRNA levels were studied in GT1-7 hypothalamic neuronal cells. Dose-response and time-course studies revealed that TPA (10(-8) M) acutely increased GnRH secretion 3-fold at 3-6 h, which then declined to baseline at 24 h, while it progressively decreased GnRH mRNA levels by 50% and 70% at 6 and 24 h, respectively. To ensure that these effects were due to activation and not down-regulation of PKC, cells were treated for 30 min with TPA (10(-8) M). This brief exposure to TPA also resulted in a decrease (60%) in GnRH mRNA levels at 6 h, with a 1.5- to 2-fold increase in GnRH secretion compared to control values, suggesting that activation of PKC decreases the pretranslational expression of GnRH while increasing GnRH secretion. Additional studies measured PKC activity and documented a shift from a cytosolic to a membrane fraction after incubation with TPA, again supporting PKC activation. Exposure of GT1-7 cells to staurosporine (10(-8) M), a PKC inhibitor, resulted in no change in the level of GnRH mRNA or secretion at 6 h. However, incubation with both TPA and staurosporine prevented the decrease in GnRH mRNA levels and partially blocked the increase in GnRH secretion induced by TPA. We conclude that TPA, by activating the PKC pathway, acutely increases GnRH secretion, but dramatically decreases GnRH gene expression. The exact mechanism of these divergent effects on the synthesis and secretion of GnRH remain to be elucidated.


Subject(s)
Gene Expression/drug effects , Gonadotropin-Releasing Hormone/genetics , Protein Kinase C/metabolism , Tetradecanoylphorbol Acetate/pharmacology , Alkaloids/pharmacology , Animals , Cell Line , DNA Probes , Dose-Response Relationship, Drug , Enzyme Activation/drug effects , Gonadotropin-Releasing Hormone/metabolism , Kinetics , Mice , Nucleic Acid Hybridization , Protein Kinase C/antagonists & inhibitors , Rats , Staurosporine , Tetradecanoylphorbol Acetate/administration & dosage
15.
BMC Cell Biol ; 2: 1, 2001.
Article in English | MEDLINE | ID: mdl-11178103

ABSTRACT

BACKGROUND: Atherosclerosis and coronary heart disease (CHD) are significant contributors to morbidity and mortality in developed countries. A noted exception is the low mortality of CHD in France, particularly the southwest region. This phenomenon, commonly referred to as the French paradox, may be associated with high consumption of red wine. We investigate whether the cardioprotective activity of red wine may involve the grape skin-derived polyphenol, resveratrol. We further test the possibility that resveratrol acts by modulating structural and functional changes in endothelial cells lining the blood vessel wall. RESULTS: Bovine pulmonary artery endothelial cells (BPAEC) were incubated with resveratrol, with and without concurrent exposure to simulated arterial shear stress. Resveratrol significantly affected proliferation and shape of BPAEC; growth was suppressed and cells became elongated, based on morphologic analysis of rhodamine-conjugated phalloidin stained F-actin by confocal microscopy. Using selective signaling inhibitors, we showed that the resveratrol-induced cellular phenotype was dependent on intracellular calcium and tyrosine kinase activities, and assembly of actin microfilaments and microtubules, but was unrelated to PKC activity. Exposure to simulated arterial flow revealed that, whereas controls cells easily detached from the culture support in a time-dependent manner, resulting in total cell loss after a 5 min challenge with simulated arterial flow conditions, a significant percentage of the treated cells remained attached to the cultured plastic coverslips under identical experimental conditions, suggesting that they adhered more strongly to the surface. Western blot analysis shows that whereas cells treated with 25 microM and 100 microM resveratrol had no change in total ERK1/2, treatment did result in an increase in phosphorylated ERK1/2, which probably involved stabilization of the active enzyme. An increase in nitric oxide synthase expression was detected as early as 6 h and persisted for up to 4 days of treatment. CONCLUSIONS: Results of our studies show that resveratrol interacts with endothelial cells in vitro to elicit morphological and structural changes; the observed changes support the interpretation that resveratrol acts as a cardioprotective agent.


Subject(s)
Cardiotonic Agents/pharmacology , Cytoskeleton/ultrastructure , Endothelium, Vascular/drug effects , Pulmonary Artery/cytology , Stilbenes/pharmacology , Actin Cytoskeleton/drug effects , Actin Cytoskeleton/ultrastructure , Animals , Calcium Signaling , Cattle , Cell Adhesion , Cell Division/drug effects , Cells, Cultured , Cytoskeleton/drug effects , Dose-Response Relationship, Drug , Endothelium, Vascular/cytology , Endothelium, Vascular/physiology , Endothelium, Vascular/ultrastructure , Enzyme Inhibitors/pharmacology , Eukaryotic Initiation Factor-4E/metabolism , Microtubules/drug effects , Microtubules/ultrastructure , Mitogen-Activated Protein Kinases/metabolism , Nitric Oxide Synthase/metabolism , Nitric Oxide Synthase Type III , Protein-Tyrosine Kinases/antagonists & inhibitors , Pulmonary Artery/physiology , Resveratrol , Signal Transduction/drug effects , Stress, Mechanical
16.
Mol Cell Endocrinol ; 99(2): 177-82, 1994 Mar.
Article in English | MEDLINE | ID: mdl-8206325

ABSTRACT

We previously showed that activation of protein kinase C (PKC) with the phorbol ester, 12-O-tetradecanoylphorbol 13-acetate (TPA) in GT1-7 hypothalamic cells decreases GnRH mRNA levels in a dose and time dependent fashion. In the present studies, we examined the mechanism of this effect. Analysis of the half-life of GnRH mRNA levels after transcriptional arrest with actinomycin-D (5 micrograms/ml) estimated the half-life of GnRH mRNA to be 22 h. TPA treatment did not alter the GnRH mRNA half-life directly, suggesting that the effects of TPA occur predominantly at the level of gene transcription. Exposure of cells transiently transfected with various deletion constructs of the rat (r)GnRH promoter to TPA resulted in a decrease of 60% in luciferase reporter activity. This repression was maintained in constructs deleted to position -126 and was lost with further deletion to position -73. In conclusion, these experiments suggest that phorbol esters repress GnRH expression at the level of transcription through DNA sequences in the proximal rGnRH promoter.


Subject(s)
Gene Expression Regulation/drug effects , Gonadotropin-Releasing Hormone/genetics , Promoter Regions, Genetic , Tetradecanoylphorbol Acetate/pharmacology , Transcription, Genetic/drug effects , Animals , Base Sequence , Blotting, Northern , Cell Line , DNA/chemistry , Dactinomycin/pharmacology , Half-Life , Mice , Protein Kinase C/metabolism , RNA, Messenger/metabolism , Rats
17.
J Steroid Biochem Mol Biol ; 62(5-6): 461-6, 1997 Aug.
Article in English | MEDLINE | ID: mdl-9449250

ABSTRACT

Studies suggest that the steroid, dehydroepiandrosterone (DHEA) can exert effects directly, in addition to its indirect role serving as a precursor for other steroids such as androgens and estrogens. Because DHEA is one of the most abundant adrenal steroids secreted in man, we investigated the functional activity of DHEA on the classic estrogen response element (ERE) in the presence of the estrogen receptor (ER) in transiently transfected cells. GT1-7 hypothalamic neuronal cells, devoid of the estrogen receptor, were transiently transfected with the estrogen receptor expression plasmid (HEGO) and the estrogen response element luciferase (ERELUC) reporter vector. As expected, a dose-response stimulation of luciferase activity was observed in cells treated with estradiol. Concentrations of estradiol from 10(-10)-10(-6) M resulted in a 136-195 percent increase in luciferase activity compared with control. A dose-response stimulation was also observed in the cells treated with DHEA. A maximum stimulation of 177 percent increase in luciferase activity compared with control was observed with DHEA at a concentration of 10(-5) M. Both the estradiol and DHEA stimulation of ERE luciferase activity was inhibited by the estrogen receptor antagonist, ICI 182,780. The aromatase inhibitor, formestane in combination with estradiol or DHEA had no effect on luciferase activity, suggesting that the effect of DHEA is independent of its conversion to estradiol. Estradiol levels, as measured by ELISA, were appropriately elevated in the estradiol-treated cells but were not significantly different from the control cells in the DHEA-treated cells. These studies suggest a functional in vitro role of DHEA in activating the ERE in the presence of the classic ER.


Subject(s)
Dehydroepiandrosterone/pharmacology , Receptors, Estrogen/genetics , Androstenedione/analogs & derivatives , Androstenedione/pharmacology , Animals , Aromatase Inhibitors , Cell Line , Dehydroepiandrosterone/metabolism , Enzyme Inhibitors/pharmacology , Estradiol/analogs & derivatives , Estradiol/metabolism , Estradiol/pharmacology , Estrogen Antagonists/pharmacology , Fulvestrant , Genes, Reporter , Genetic Vectors , Humans , Luciferases/genetics , Mice , Receptors, Estrogen/antagonists & inhibitors , Receptors, Estrogen/metabolism , Transfection
18.
Br J Ophthalmol ; 85(7): 861-7, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11423463

ABSTRACT

AIM: To investigate the efficacy of "ex vivo" adenoviral vector mediated gene transfection of human conjunctival epithelial cell as a possible route for gene therapy for the distribution of anti-inflammatory agents for the potential treatment of immune mediated ocular inflammatory disorders. METHODS: Human conjunctival cells (HCs) were cultured with various concentrations of recombinant adenoviral vectors carrying a reporter gene LacZ, GFP, or an immunomodulating cytokine vIL-10. vIL-10 in culture supernatant was detected by sandwich ELISA and biological activity was assessed by suppression of ConA stimulated splenocyte proliferation. X-gal and GFP expression was assessed by histochemistry. RESULTS: The extent of adenoviral vector mediated transfer of both reporter genes and vIL-10 was dose dependent. LacZ expression could be detected for at least 50 day after infection with multiple of infection (MOI) 200. Following AdCMVvIL-10 transduction, vIL-10 protein expression occurred between 4-6 days post-transduction, and was maintained at a detectable level for at least 1 month. Secreted vIL-10 showed biological activity, significantly inhibiting Con A induced splenocyte proliferation. Additionally, transfection of HCs with two Adv vectors, one carrying LacZ and the other carrying GFP, resulted in co-expression within a single cell. CONCLUSION: These results confirm previous successful adenoviral vector mediated gene transfer to HCs and further show that expression can be maintained. Furthermore the data show HCs can secrete biologically active vIL-10 that could be developed as a strategy to suppress immune mediated disorders. The successful co-transduction of HCs as described for other tissues, opens avenues to develop a multiple target gene therapy locally.


Subject(s)
Adenoviridae/genetics , Conjunctivitis, Allergic/therapy , Genetic Vectors/administration & dosage , Interleukin-10/genetics , Transduction, Genetic/methods , Animals , Cell Division , Cells, Cultured , Culture Media, Conditioned/pharmacology , Green Fluorescent Proteins , Humans , Interleukin-10/analysis , Luminescent Proteins/genetics , Mice , Mice, Inbred C57BL , Spleen/cytology
19.
Int J Mol Med ; 8(1): 3-17, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11408943

ABSTRACT

Coronary heart disease (CHD) has been and remains a major contributor to morbidity and mortality in developed countries. The most common form of CHD in the western world is atherosclerosis (AS), especially of the major coronary arteries. Failure to maintain an intact endothelium, as a result of episodic and/or persistent injury and perturbation of the vascular endothelium, promotes formation of fatty streaks which are considered initiation events of AS. Cellular constituents contributing to endothelial injury include endothelial cells, monocytes, platelets, and smooth muscle cells. Individuals diagnosed with AS face complex, enduring clinical complications and enormous medical costs. Simple and easily compliant prevention and treatment measures are therefore strategic considerations in the management of this vascular disease. Based on known risk factors for CHD, priorities in AS prevention should include smoking cessation, blood pressure control, and diet modification. In recent years, the possible benefits of low to moderate consumption of alcoholic beverages, particularly of red wine, in the prevention of heart disease has received increasing attention and debate in the popular media as well as in the scientific community. Such attention has been prompted by research findings supporting a relationship between red wine consumption and the French paradox. This phenomenon refers to people residing in certain parts of France where red wine is customarily consumed during meals having a low CHD mortality, despite living a lifestyle considered to have comparably high CHD risks, as those in the US and many other developed countries. Studies have reported that the cardioprotective effects of red wine are greater than those attributed solely to ethanol and other types of alcoholic beverages. The mechanism(s) underlying the greater CHD protective benefits of red wine have not been elucidated. Recently the polyphenol resveratrol (3,5,4'-trihydroxy-trans-stilbene), known to be abundantly present in red wine, compared to white wine, beer, or spirits, has been demonstrated to elicit a broad spectrum of biological responses in in vitro and in animal studies, including effects that are compatible with the cardioprotective roles proposed for red wine. These recently described effects of resveratrol will be reviewed in this article. We will first summarize published data showing an inverse association between consumption of alcoholic beverages/red wine and risk of CHD. A review of biosynthesis of resveratrol and its presence in food groups and wines will follow. Recent studies relating exposure to wine/resveratrol with reduction in myocardial damage during ischemia-reperfusion, modulation of vascular cell functions, inhibition of LDL oxidation, and suppression of platelet aggregation will be presented. The last section of this review will focus on a discussion of mechanism(s) by which resveratrol acts as a potential cardioprotective agent.


Subject(s)
Antioxidants/therapeutic use , Coronary Disease/prevention & control , Stilbenes/therapeutic use , Wine , Animals , Humans , Resveratrol
20.
Am J Manag Care ; 7 Spec No: SP5-16, 2001 Sep 25.
Article in English | MEDLINE | ID: mdl-11599675

ABSTRACT

Osteoporosis is a prevalent condition among elderly women and is associated with an increased risk for fractures. With the burgeoning size of the elderly population, a practitioner is likely to face many questions regarding the evaluation and management of postmenopausal osteoporosis. This review discusses and compares available therapies. All women should have adequate calcium and vitamin D intake. Women diagnosed as having osteoporosis should be evaluated for secondary causes of osteoporosis and risk factors for falls. For women with postmenopausal osteoporosis, therapy with hormone replacement, bisphosphonates (alendronate sodium or risedronate sodium), raloxifene hydrochloride, or calcitonin should be considered. The results of ongoing studies will help refine the strategies used for management of postmenopausal osteoporosis.


Subject(s)
Osteoporosis/diagnosis , Osteoporosis/drug therapy , Postmenopause , Women's Health , Aged , Algorithms , Bone Density , Calcitonin/administration & dosage , Calcium/administration & dosage , Diphosphonates/administration & dosage , Estrogens/administration & dosage , Female , Fractures, Bone/etiology , Humans , Osteoporosis/complications , Osteoporosis/physiopathology , Raloxifene Hydrochloride/administration & dosage , Risk Factors , Selective Estrogen Receptor Modulators/administration & dosage , United States/epidemiology
SELECTION OF CITATIONS
SEARCH DETAIL