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C Trocmé

Publications and source records attributed to C Trocmé.

10 recordsLinked to original sources
PubMed2001

CREM and ICER are differentially implicated in trans-synaptic induction of tyrosine hydroxylase gene expression in adrenal medulla and sympathetic ganglia of rat.

Reserpine treatment leads to a trans-synaptic increase of the tyrosine hydroxylase (TH) gene transcription rate, mRNA and protein levels in catecholaminergic tissues including the adrenal medulla (AM) and the superior cervical ganglia (SCG). The TPA-responsive element plays an important role in the trans-synaptically-induced transcription of the TH gene in the AM, whereas it does not appear to be involved in the SCG (Trocmé et al. [1997] J. Neurosci. Res. 48:489-498). In this study, we show that another regulatory sequence of the TH proximal promoter, the cAMP-responsive element (CRE), binds different factors in the AM and in the SCG. To elucidate the dynamics of promoter regulation a complete time course analysis was conducted. Reserpine treatment enhances, between 1 hr and 8 hr after the injection, the expression and the binding of the repressor ICER in the AM, whereas in the SCG it enhances the binding of CREM factors. These results suggest that the mechanisms mediating trans-synaptic induction of the TH gene are different in the AM and SCG. The interplay between positive and negative transcription factors and their kinetics of action are responsive of the long-term regulation of the TH gene.

Adrenal Medulla↗
PubMed2000

TIMP-1/MMP-9 imbalance in an EBV-immortalized B lymphocyte cellular model: evidence for TIMP-1 multifunctional properties.

Tissue inhibitors of metalloproteinases (TIMPs) were initially described as agents controlling metalloproteinase activity. The purpose of this study was to investigate the expression and the roles of TIMP-1 secreted by Epstein-Barr-virus (EBV)-immortalized B lymphocytes. TIMP-1 was isolated from conditioned medium of interleukin (IL)-1beta stimulated EBV-B lymphocytes; purified TIMP-1 was identified by mass spectrometry and immunochemistry. TIMP-1-free MMP-9 was quantified after purification by zymography and enzyme-linked immunosorbent assay. EBV-B lymphocyte-secreted TIMP-1 inhibited MMP-9 gelatinolytic activity resulting in decreased B-cell transmigration as measured in vitro. The release of huge amounts of TIMP-1 in proportion to MMP-9 from B lymphocytes after EBV transformation was shown to be correlated with secretion of IL-10 and dependent on culture time. In contrast, there was little TIMP-1 and almost no IL-10 released from native B cells, suggesting a possible IL-10 mediated autocrine regulation mechanism of TIMP-1 synthesis. The MMP-9/TIMP-1 imbalance observed in the culture medium of EBV-B lymphocytes (TIMP-1>MMP-9) and of native B cells (MMP-9>TIMP-1) is suggestive of a new function for TIMP-1. We propose that TIMP-1 acts as a survival factor controlling B-cell growth and apoptosis through an autocrine regulation process involving IL-10 secreted by EBV-B lymphocytes.

Amino Acid Sequence↗
PubMed1998

Human B lymphocytes synthesize the 92-kDa gelatinase, matrix metalloproteinase-9.

Matrix metalloproteinases (MMPs) are involved in the remodeling of connective tissue as well as in disease states associated with acute and chronic inflammation or tumoral metastatic processes. Despite detailed and extensive studies of the mechanisms of lymphocyte extravasation, remarkably little is known about the expression and regulation of metalloproteinases involved in the migratory process. By using zymography and reverse transcription-polymerase chain reaction experiments, we have demonstrated that Epstein-Barr virus-immortalized B lymphocytes are able to secrete a 92-kDa metalloproteinase with gelatinolytic activity which has been purified and identified as being MMP-9. Moreover, the tissue inhibitor of metalloproteinase was shown to be constitutively expressed by the B cells. The expression of 92-kDa gelatinase is mediated by cytokines, growth factors, lipopolysaccharide, concanavalin A, and the tumor promotor phorbol 12-myristate 13-acetate. Time dependence activity increased rapidly up to 24 h of incubation with lipopolysaccharide or concanavalin A stimulation while it requires a delay and more time to have an optimum effect when cytokines were the stimulating agents; transforming growth factor-beta abolished 92-kDa gelatinase production. Both staurosporine and wortmannin are inductive stimuli, and the level of MMP-9 secreted into the media is greater than that observed with other agents except concanavalin A. Elicitation of the chemotactic migration of B cells through a model basement membrane by lipopolysaccharide was shown to be correlated with gelatinase expression and inhibited by 7 mM captopril. Our study indicates that Epstein-Barr virus-B lymphocytes express 92-kDa gelatinase, the production of which can be modified by a variety of physiological and pharmacological signals which have been shown to differ according to the cell type.

Androstadienes↗
PubMed1998

CRE and TRE sequences of the rat tyrosine hydroxylase promoter are required for TH basal expression in adult mice but not in the embryo.

Tyrosine hydroxylase (TH), the rate-limiting enzyme in the biosynthesis of catecholamine neurotransmitters, is expressed in a restricted number of areas, and subject to numerous regulations during development and in adulthood. Two transcription factor binding sites present in the proximal region of the TH gene, the TPA-responsive element (TRE) and the c-AMP responsive element (CRE), have been shown to play important roles in TH gene regulation in vitro. In order to elucidate in vivo the role of these two sites, we produced transgenic mice bearing a 5.3-kb fragment from the 5' flanking sequence of the TH gene with mutations in either the CRE-or TRE-sites. Using the intact 5.3-kb fragment fused to two different reporter genes (HSV1-tk and lacZ), we show that this promoter fragment is able to specifically direct expression in catecholaminergic tissues both in adult mice and embryos. Interestingly, the CRE- and TRE-mutated transgenes were not expressed in adult mice, contrary to the situation in embryos where they were specifically expressed in catecholaminergic regions. These results demonstrate that the CRE and TRE play an essential role in basal TH expression in adult tissues in vivo. Moreover, they suggest that distinct transcription factors are involved in TH regulation in developing and adult tissues. In support of this, gel mobility shift experiments revealed a complex present only in embryonic tissues. Taken together, these data highlight the diversity of the mechanisms underlying the establishment and maintenance of the catecholaminergic phenotype.

Adrenal Medulla↗
PubMed1997

AP-1 mediates trans-synaptic induction of tyrosine hydroxylase gene expression in adrenal medulla but not in superior cervical ganglia.

Reserpine treatment leads to a rapid trans-synaptic increase of the tyrosine hydroxylase (TH) gene transcription rate and mRNA levels in catecholaminergic tissues including the adrenal medulla (AM) and the superior cervical ganglia (SCG). In the AM, the formation of a specific protein complex with the TPA-responsive element located in the proximal region of the TH gene was enhanced between 30 min and 8 hr following the injection. This complex appears to contain a member of the Fos family and an antigenically related Jun protein. Moreover, the prolonged and enhanced expression of the c-Fos protein in the AM and its phosphorylation are likely to contribute to the increased TH transcription following reserpine treatment. Most strikingly, in the SCG, the trans-synaptic induction of TH transcription is transduced by totally different mechanisms, since no AP-1 complex and only minute amounts of c-Fos immunoreactivity were detected. Our study provides the first demonstration that, following the same stimulus, the induced expression of a single gene is mediated by different cis- and trans-acting factors in two distinct tissues sharing the same embryonic origin.

Adrenal Medulla↗
PubMed1983

[Not Available].

Explore the source record for details and available documents.

Edema↗
PubMedDate not supplied

[Focalized matrix proteolysis and inflammation].

The zinc metalloproteinases (MMPs or matrixins) are capable of damaging most of the constituents of the extra-cellular matrix and the basement membrane. The matrix proteolysis is the result of an imbalance both in the turnover of these constituants and in the ratio of the tissue inhibitors of metalloproteinases (TIMPs) versus metalloproteinases. After a brief description of the nature and structure of MMPs and TIMPs, this article reports on recent progress concerning the intra and extra-cellular activation mechanisms of proenzymes (proMMPs) which bring into play a series of proteolytic activations involving different proteinase families. Two points are stressed: 1) the main sites of focalized matrix proteolysis regulation, illustrated in the cellular interaction of inflammation, and 2) the wide phenotypic variety of MMPs and TIMPs.

Amino Acid Sequence↗