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V Gentile

Publications and source records attributed to V Gentile.

At least 37 records · Page 2Linked to original sources
PubMed2000

[Role of nitric oxide in the urogenital system: physiology and pathology].

A review has been made on the role of nitric oxide in the physiology and pathophysiology of penis, bladder, prostate and the nervous structures involved in the urinary control. NO is an essential mediator in penile erection and his action can be modulated by sildenafil. Nitric oxide could be involved in bladder detrusor relaxation and in the development of interstitial cystitis. Little is known about the role of nitric oxide in the physiology and pathophysiology of the prostate: this molecule is released by the epithelial and stromal cells of the prostate, and by the prostatic nerves. Actually some studies hypothesize a role played by nitric oxide in benign prostatic hyperplasia development.

Humans↗
PubMed1999

Tissue transglutaminase expression in quail epiphyseal chondrocytes.

Tissue transglutaminase (tTGase) is a GTP-binding Ca(2+)-dependent enzyme which catalyses the post-translational modification via epsilon(gamma-glutamyl)lysine bridges. The physiological role of tTGase is not fully understood. It has been shown that in cartilage the expression of tTGase correlates with terminal differentiation of chondrocytes. Recent evidence suggests that the GTP-binding activity of tTGase may play a role in the control of cell cycle progression thus explaining some of the suggested roles for the enzyme.tTGase activity is present in primary cultures of epiphyseal chondrocytes and increases transiently upon retinoic acid (RA) treatment. Increase in enzyme activity occurs upon RA addition and is accompanied by a parallel increase in protein and mRNA levels. Stimulation of tTGase expression by RA correlates with suppression of cell growth and occurs independently of cell adhesion and cell differentiation.tTGase expression is not observed in MC2, a permanent chondrocyte cell line derived from retrovirus infected chondrocytes. RA treatment fails to activate tTGase expression in MC2 cells and to completely suppress cell proliferation. Our findings lend support to the idea that tTGase might play a role in non-dividing cultured chondrocytes.

Animals↗
PubMed1999

Pathogenesis of inclusion bodies in (CAG)n/Qn-expansion diseases with special reference to the role of tissue transglutaminase and to selective vulnerability.

At least eight neurodegenerative diseases, including Huntington disease, are caused by expansions in (CAG)n repeats in the affected gene and by an increase in the size of the corresponding polyglutamine domain in the expressed protein. A hallmark of several of these diseases is the presence of aberrant, proteinaceous aggregates in the nuclei and cytosol of affected neurons. Recent studies have shown that expanded polyglutamine (Qn) repeats are excellent glutaminyl-donor substrates of tissue transglutaminase, and that the substrate activity increases with increasing size of the polyglutamine domain. Tissue transglutaminase is present in the cytosol and nuclear fractions of brain tissue. Thus, the nuclear and cytosolic inclusions in Huntington disease may contain tissue transglutaminase-catalyzed covalent aggregates. The (CAG)n/Qn-expansion diseases are classic examples of selective vulnerability in the nervous system, in which certain cells/structures are particularly susceptible to toxic insults. Quantitative differences in the distribution of the brain transglutaminase(s) and its substrates, and in the activation mechanism of the brain transglutaminase(s), may explain in part selective vulnerability in a subset of neurons in (CAG)n-expansion diseases, and possibly in other neurodegenerative disease. If tissue transglutaminase is found to be essential for development of pathogenesis, then inhibitors of this enzyme may be of therapeutic benefit.

Animals↗
PubMed1999

Changes in tissue transglutaminase activity and expression during retinoic acid-induced growth arrest and apoptosis in primary cultures of human epithelial prostate cells.

We treated primary epithelial cells from human normal prostate (NEPC) and prostate cancer (CEPC) with all-trans-retinoic acid (RA) to study whether it regulates the activity of tissue transglutaminase (tTGase), an enzyme that accumulates in cells undergoing apoptosis. tTGase activity was assessed by [14C]spermidine incorporation; tTGase, P53, Bcl-2, and p21 protein levels were evaluated by Western blotting; and RA receptors (RAR alpha, -beta, and -gamma), tTGase, retinol-binding protein (RBP), and cellular RBP type I transcripts were determined by semiquantitative RT-PCR. After 72-96 h of 10(-6) mol/L RA treatment, cell growth inhibition and apoptosis were associated with increased tTGase activity in both NEPC and CEPC, and with increased tTGase protein and messenger ribonucleic acid levels only in NEPC. Moreover, RA down-regulated RAR alpha and -beta and increased RBP messenger ribonucleic acid levels in NEPC, whereas it increased RAR beta gene expression and decreased Bcl-2 protein levels in CEPC. Our results suggest that RA induces tTGase gene expression and enzyme activity in normal prostate cells, and that RA-regulated pathways are impaired in cancer cells. Moreover, down-regulation of Bcl-2 protein and up-regulation of RAR beta suggest that retinoid may act on the genetic defect responsible for prostate cancer progression.

Apoptosis↗
PubMed1998

Tissue transglutaminase expression affects hypusine metabolism in BALB/c 3T3 cells.

Post-translational formation of hypusine in eukaryotic initiation factor 5A (eIF-5A) is essential for cell viability. Recently, we showed that hypusine protein is an in vitro substrate for transglutaminases (TGases). We report the effect of tissue TGase expression on the in vivo hypusine metabolic pathway. The stable expression of tTGase in BALB/c 3T3 cells induced a 100-fold reduction of hypusine levels and a 50% increase of gamma-glutamyl-omega-hypusine formation. Such changes were paralleled by a consistent decrease in the free polyamine pool and an enhancement of their excretion and of the formation of their gamma-glutamyl derivatives. These effects occurred together with a significant reduction of cell proliferation. In this report we suggest, for the first time, that tTGase affects hypusine metabolism, thus regulating the eIF-5A activity and cell proliferation.

3T3 Cells↗
PubMed1998

Tissue transglutaminase-catalyzed formation of high-molecular-weight aggregates in vitro is favored with long polyglutamine domains: a possible mechanism contributing to CAG-triplet diseases.

To investigate possible biochemical mechanisms underlying the "toxic gain of function" associated with polyglutamine expansions, the ability of guinea pig liver tissue transglutaminase to catalyze covalent attachments of various polyamines to polyglutamine peptides was examined. Of the polyamines tested, spermine is the most active substrate, followed by spermidine and putrescine. Formation of covalent cross links between polyglutamine peptides and polyamines yields high-M(r) aggregates--a process that is favored with longer polyglutamines. In the presence of tissue transglutaminase, purified glyceraldehyde-3-phosphate dehydrogenase (a key glycolytic enzyme that binds tightly to the polyglutamine domains of both huntingtin and dentatorubral-pallidoluysian atrophy proteins) is covalently attached to polyglutamine peptides in vitro, resulting in the formation of high-M(r) aggregates. In addition, endogenous glyceraldehyde-3-phosphate dehydrogenase of a Balb-c 3T3 fibroblast cell line overexpressing human tissue transglutaminase forms cross-links with a Q60 polypeptide added to the cell homogenate. Possibly, expansion of polyglutamine domains (thus far known to occur in the gene products associated with at least seven neurodegenerative diseases) leads to increased/aberrant tissue transglutaminase-catalyzed cross-linking reactions with both polyamines and susceptible proteins, such as glyceraldehyde-3-phosphate dehydrogenase. Formation of cross-linked heteropolymers may lead to deposition of high-M(r) protein aggregates, thereby contributing to cell death.

Animals↗
PubMed1998

Simultaneous detection of HPV and other sexually transmitted agents in chronic urethritis.

BACKGROUND: Many pathogens may be responsible of Non Gonococcal Urethritis (NGU) with the possible occurrence of symptomatic and asymptomatic mixed viral and bacterial infections. In particular, genital papillomaviruses (HPVs) have been searched since they are linked to both benign and malignant lesions of the penis and urethra and the presence of a potential male carried state has received limited scrutiny while the screening of sexually active females has received substantial attention. METHODS: In male patients affected by chronic NGU, the presence of DNA of Chlamydia trachomatis, herpes simplex virus (HSV) type 1 and 2 and human papillomaviruses by PCR and the occurrence of Gram positive and Gram negative micro-organisms, of Mycoplasma hominis and Ureaplasma urealyticum, by conventional cultural methods have been investigated. RESULTS: Results obtained indicated a high percentage of mixed infections, up to 36%. Genital HPV DNA was detected in 31% of specimens positive for two or more agents, and HSV DNA was detected in 10% of studied population. CONCLUSIONS: The concomitant presence of different infectious agents could determine latent, sub-clinical or chronic infections with periodic reactivation. In particular results suggest that HPV and HSV may stimulate cytokine production which can up regulate the expression of other infectious agents and may be responsible for latent chlamydial infections characterised by the persistence of this micro-organism in an altered form, viable but in a culture negative state. Therefore an increased awareness of mixed infections is relevant to define the management and treatment of chronic urethritis.

Adult↗
PubMed1997

tTGase/G alpha h protein expression inhibits adenylate cyclase activity in Balb-C 3T3 fibroblasts membranes.

Stably transfected Balb-C 3T3 fibroblasts (clone 5), overexpressing a catalytically active tissue transglutaminase, showed a basal adenylate cyclase activity lower than control cells (clone 1). Several modulators of the adenylate cyclase activity (forskolin, Mn2+ and pertussis toxin) showed the existence of a marked negative control on the adenylate cyclase activity present in clone 5 cells. Very interestingly, this same marked negative control was also found in a Balb-C 3T3 fibroblast clone stably transfected with a mutagenized human tissue transglutaminase (mut277 cys > ser) virtually devoid of transglutaminase catalytic activity (clone Ser). Conversely, a significant increase of the adenylate cyclase activity was observed in bovine aortic endothelial cells after the lowering of tissue transglutaminase expression levels by the transfection of an eukaryotic expression vector containing the gene for tissue transglutaminase in antisense orientation. All these findings suggest a possible role for type II tissue transglutaminase as a negative modulator of the adenylate cyclase activity in different cell types, beside its transglutaminase enzyme activity.

3T3 Cells↗
PubMed1997

Lack of 'tissue' transglutaminase protein cross-linking leads to leakage of macromolecules from dying cells: relationship to development of autoimmunity in MRLIpr/Ipr mice.

Genetic defects of the CD95 (Fas/Apo-1) receptor/ligand system, has recently been involved in the development of human and murine autoimmunity. We investigated whether a deregulation of the ;tissue' transglutaminase (tTG), a multifunctional enzyme which is part of the molecular program of apoptosis, may act as a cofactor in the development of autoimmunity. We found that MRLlpr/lpr, which are characterized by a defect in the CD95 receptor and suffer of a severe systemic lupus erythematosus-like disease, produce large amounts of circulating tTG autoantibodies. This phenomenon is paralleled by an abnormal accumulation of an inactive enzyme protein in the accessory cells of lymphoid organs. To investigate the molecular mechanisms by which tTG inhibition may contribute to the development of autoimmunity we generated a cell culture model system consisting of L929 cells stably transfected with a full length tTG cDNA. When L929 cells were killed by Tumor Necrosis Factor alpha (TNFalpha) a pronounced release of DNA and Lactate Dehydrogenase (LDH) was observed. Overexpression of tTG in these cells largely prevented the leakage of macromolecules determined by TNFalpha treatment, an effect which is abolished by inactivating the enzyme cross-linking activity by a synthetic inhibitor. These in vitro observations provided the basis to explain the increased levels of plasmatic LDH we detected in MRLlpr/lpr mice. These data suggest that lack of an active tTG may represent a cofactor in the development of autoimmunity.

Journal Article↗
PubMed1996

Alprostadil sterile powder formulation for intracavernous treatment of erectile dysfunction.

The main aim of this double-blind randomized crossover study was to compare the efficacy and safety of alprostadil sterile powder (Caverject) (PGE1) in a new sterile powder formulation versus placebo in producing erection in patients with erectile dysfunction. Each patient was treated with 5 or 10 micrograms PGE1 and placebo in random order. If the results of the three injections were unsatisfactory, 20 micrograms PGE1 was administered in an open fashion. A total of 45 patients were recruited and evaluated; 31/45 patients (68.8%) responded to at least one injection of alprostadil. A dose-response relation was observed during the double-blind phase; the 10-micrograms dose was effective in 55.5% of patients. The acceptability and tolerability of the preparation, evaluated both clinically and by laboratory tests, was very good. In particular, only four drug-related side effects were observed, three (penile burning, penile pain and pain after injection) after 10 micrograms and one (hematoma) after 5 micrograms PGE.

Adolescent↗
PubMed1996

In vitro study of a double infection by herpes simplex virus type 2 and Chlamydia trachomatis.

Sexually transmitted diseases (STDs) may recognize multiple etiological agents. Among them, Chlamydia trachomatis (Ct) and herpes simplex virus type 2 (HSV-2) cause symptomatic, subclinical and asymptomatic infections of the urogenital tract which can lead to serious sequelae. In the present study the coinfection and superinfection by Ct and HSV-2 in epithelial cultured cells from human cervix (HeLa 229) are described. A double infection, followed by the intracellular synthesis of chlamydial and viral antigens, was established. Both synergistic and interfering phenomena were recorded: viral antigen synthesis resulted increased whereas Ct inclusion bodies were produced to a lower extent.

Antigens, Bacterial↗
PubMed1995

The importance of the GTP-binding protein tissue transglutaminase in the regulation of cell cycle progression.

Tissue transglutaminase (tTgase) is a GTP-binding Ca(2+)-dependent enzyme which catalyses the post-translational modification of proteins via epsilon(gamma-glutamyl) lysine bridges. Recent evidence suggests that the GTP-binding activity of tTgase may be important in intracellular signaling thus explaining some of the diverse suggested roles for the enzyme. In the following work a malignant hamster fibrosarcoma (Met B) has been stably transfected with both the full length tTgase cDNA (wild type) and a mutant form of the cDNA whereby the active site cysteine (Cys 277) has been replaced by serine. Expression of this mutant cDNA leads to a protein with GTP binding activity which is deficient of protein crosslinking activity. When synchronised into S-phase and allowed to progress through the cell cycle tTgase transfected clones (both mutant and wild type), when compared to transfected controls, show a delayed progression from S-phase to G2/M when analysed by flow cytometry which appears to be elicited by the G-protein activity of the tTgase.

Animals↗
PubMed1995

Isolation and characterization of the human tissue transglutaminase gene promoter.

Tissue transglutaminase belongs to a family of calcium-dependent enzymes, the transglutaminases that catalyze the covalent cross-linking of specific proteins by the formation of epsilon (gamma-glutamyl)lysine isopeptide bonds. The goal of this study has been the isolation and characterization of the human tissue transglutaminase gene promoter. Genomic DNA clones, spanning the 5' region of the gene, were isolated and the structure of the 5'-end of the human tissue transglutaminase gene was determined. 1.74 kilobases of flanking DNA were sequenced and were found to contain a TATA box element (TATAA), a CAAT box element (GGACAAT), a series of potential transcription factor-binding sites (AP1, SP1, interleukin-6 response element), and a glucocorticoid response elements. Transient transfection experiments showed that this DNA fragment included a functional promoter, which is constitutively active in multiple cell types.

3T3 Cells↗
PubMed1994

The human tissue transglutaminase gene maps on chromosome 20q12 by in situ fluorescence hybridization.

A cDNA encoding for the human tissue transglutaminase gene has been used to identify the chromosomal localization of the corresponding structural gene. The precise chromosomal and subregional localizations have been established by using in situ fluorescence mapping with a recombinant lambda-Zap phage containing the full cDNA coding sequence. The study showed that the human tissue transglutaminase gene is localized on chromosome 20 and, more precisely, within the band 20q12. To date, this is the third member of the transglutaminase gene family to be mapped. Human factor XIIIa (plasma transglutaminase), human keratinocyte transglutaminase (type I), and human tissue transglutaminase (type II) genes, although codifying for homologous enzymes, are localized on three different chromosomes.

Chromosomes, Human, Pair 20↗
PubMed1994

Chlamydia trachomatis genitourinary infections: laboratory diagnosis and therapeutic aspects. Evaluation of in vitro and in vivo effectiveness of azithromycin.

Chlamydia trachomatis (C.t.) cell culture represents a sensitive method for the diagnosis of chlamydial infection and the only one which makes it possible to determine the susceptibility of an isolate to antibiotics so that an appropriate drug can be selected for individual treatment. In 11 patients, affected by urethroprostatitis and suspected of treatment failure with standard drug regimens, either due to lack of compliance with therapy or antibiotic resistance, C.t. was isolated in McCoy cell culture from urethral swabs, after prostatic massage. The in vitro activity of azithromycin against these isolates and the in vivo efficacy of the drug in the patients treated with a single 1 g dose have been evaluated. All the C.t. strains tested were susceptible to the action of azithromycin (MIC range 0.125-1.0 microgram/ml). Bactericidal values were one dilution higher (MBC range 0.25-2.0 microgram/ml). These in vitro results are consistent with clinical observations as all the patients treated had negative culture at a 4-week follow-up visit.

Azithromycin↗
PubMed1994

Tissue transglutaminase and apoptosis: sense and antisense transfection studies with human neuroblastoma cells.

In this report, we show that the overexpression of tissue transglutaminase (tTG) in the human neuroblastoma cell line SK-N-BE(2) renders these neural crest-derived cells highly susceptible to death by apoptosis. Cells transfected with a full-length tTG cDNA, under the control of a constitutive promoter, show a drastic reduction in proliferative capacity paralleled by a large increase in cell death rate. The dying tTG-transfected cells exhibit both cytoplasmic and nuclear changes characteristic of cells undergoing apoptosis. The tTG-transfected cells express high Bcl-2 protein levels as well as phenotypic neural cell adhesion molecule markers (NCAM and neurofilaments) of cells differentiating along the neuronal pathway. In keeping with these findings, transfection of neuroblastoma cells with an expression vector containing segments of the human tTG cDNA in antisense orientation resulted in a pronounced decrease of both spontaneous and retinoic acid (RA)-induced apoptosis. We also present evidence that (i) the apoptotic program of these neuroectodermal cells is strictly regulated by RA and (ii) cell death by apoptosis in the human neuroblastoma SK-N-BE(2) cells preferentially occurs in the substrate-adherent phenotype. For the first time, we report here a direct effect of tTG in the phenotypic maturation toward apoptosis. These results indicate that the tTG-dependent irreversible cross-linking of intracellular protein represents an important biochemical event in the induction of the structural changes featuring cells dying by apoptosis.

Apoptosis↗
PubMed1994

Transfection of tissue transglutaminase into a highly malignant hamster fibrosarcoma leads to a reduced incidence of primary tumour growth.

Reduced expression of the tissue transglutaminase in both murine and human tumours has been consistently associated with tumour growth and progression. To investigate the functional effects of transglutaminase expression we have transfected a constitutive human tissue transglutaminase expression construct into a highly malignant hamster fibrosarcoma cell line Met B. Met B clones expressing the exogenous tissue transglutaminase exhibited a reduced incidence of primary tumour formation and an increased adherence to tissue culture plastic and fibronectin coated surfaces when compared to transfected and non transfected control cells. Transglutaminase transfected clones exhibited no significant differences in their growth rates measured in vitro, cell morphology or levels of spontaneous apoptosis measured by the determination of detergent insoluble apoptotic envelopes. The data demonstrates a suppressive effect of tissue transglutaminase on tumour growth and confirms its importance in the phenotypic changes associated with the cancer process.

Animals↗