1,720,986 research outputs found
A mouse reporting on ER transcriptional activity to understand the complexities of female physiology in mammals
No full textEstrogens, apoptosis and cells of neural origin
No full textIn view of the relevant complexity of estradiol actions in the nervous system, we have proposed to utilize a reductionist approach and gain an insight on its role in neural cells via the identification of the genes target for this hormone. Once obtained a biochemical footprint of the responses elicited by E2 in the neural target cells we believe that the physiological effects exerted by this hormone will be more easily elucidated; in addition, we might find novel targets for drugs aimed at mimicking or blocking E2 effects. We here summarize preliminary results obtained in the cell line SK-ER3 appropriately engineered by us to express the ERalpha. We show that nip-2, one of the genes found to be regulated by E2, is involved in the mechanisms leading to cell death. This finding led us to investigate on estrogen effects on SK-ER3 apoptosis. We found that E2 has a significant anti-apoptotic activity in SKER3 cells. These results are in line with the recent reports from other laboratories indicating that E2 may prevent death of neural cells exposed to toxic stimuli. We conclude that these initial studies seem to support the strategy of our research and underline the strength of inverse genetics in the study of the physiology of sex hormone activities
A transgenic mouse for screening and pharmacodynamic and pharmacokynetic studies of ligands of estrogen and intracellular receptors and method for its preparation
No full textThe object of the invention is a method for the production of a non-human transgenic mammal by means of which it is possible to monitor in vivo and in all the tissues the state of activation of any intracellular receptor, utilising a reporter gene inducible by natural or synthetic molecules which modulate the activity of such receptor. The mammal is question is preferably a mouse
Steroid hormones and receptors of the GABAA supramolecular complex. 1. Benzodiazepine receptor level changes in some extrahypothalamic brain areas of the female rat following sex steroid treatment
No full textThe effects of sex steroid hormones on the different receptor binding sites of the GABA(A) molecule remain unclear. In this report we have demonstrated, using autoradiography techniques, that the distribution pattern of the benzodiazepine receptors (a component of the GABA(A) molecule) in some extrahypothalamic brain regions is altered by both in vivo and in vitro sex steroid hormone treatment. In vivo administration of the sex steroids estradiol and progesterone induced a significant change in [H-3]flunitrazepam (benzodiazepine agonist) binding levels in the amygdala, and cortico and posterior brain nuclei of the female rat. In fact, elevated and diminished receptor-binding levels were obtained in the corticomedial amygdala nucleus and in the pontine central gray matter respectively, following the administration of estradiol. Significant hormonal effects were also shown for animals that received only a progesterone dose, as demonstrated by the increased and decreased receptor levels in the basolateral amygdala nucleus and cortex lamina VI and in the substantia nigra pars reticulata, respectively. It was interesting, at this point, to investigate whether the hormone effects on [H-3]flunitrazepam binding changes might be mediated through a GABA-dependent activity, because the benzodiazepine and GABA(A) receptors are coupled to a chloride ion channel in an allosteric manner. When 50 muM GABA was added to the incubation medium, substantially altered binding levels were recorded in animals that received progesterone replacement therapy only. The GABA-induced progesterone effects both increased substantially the binding levels in the oriens-pyramidalis CA1 layer of the hippocampus and in the intermediate gray layer of the superior colliculus as well as reducing receptor levels in the substantia nigra pars reticulata. Due to the significant progesterone effects on [H-3]flunitrazepam binding, we also examined whether progesterone per se or whether the potent progesterone metabolite 3alpha-hydroxy-5alpha-dihydroprogesterone was responsible for the receptor-binding changes. Addition of this progesterone metabolite not only produced greater binding changes in brain areas that responded to the in vivo progesterone treatment but also increased, in a GABA-dependent manner, [H-3]flunitrazepam binding levels in the lateral amygdala nucleus. These results suggest that the anxiolytic, sedative and anti-aggressive behavioral effects, which are progesterone-dependent, are very likely mediated via a steroid-GABAergic interaction
Reporter mice and drug discovery and development
No full textIn vivo reporter gene and imaging technologies have the potential to contribute to the drug discovery pipeline in several areas. They provide systems that enable the study of the biochemical activity of a target in disease, and in response to a drug, to be monitored over periods of time, and offer more accurate methods of measuring pharmacodynamics and toxicity. Although reporter-gene technology is in its infancy, with further refinement reporter animals could become a valuable tool in the early stages of target and lead identification and preclinical drug development
2,6-Disubstituted benzothiazoles, analogues of the aromatic core of D-luciferin : synthesis and evaluation of the affinity for Photinus pyralis luciferase
No full textA few 2,6-disubstituted benzothiazoles have been prepared as reference compounds or starting material for the preparation of derivatives containing positron emitting fluorine in the aromatic ring. Their affinity for Photinus pyralis luciferase has been evaluated and values of IC50 (8.8-45.2 μM) suggest that they are competitive inhibitors of the enzyme
Techniques : reporter mice – a new way to look at drug action
No full textIn vivo reporter gene and imaging technologies have the potential to contribute to the drug discovery pipeline in several areas. They provide systems that enable the study of the biochemical activity of a target in disease, and in response to a drug, to be monitored over periods of time, and offer more accurate methods of measuring pharmacodynamics and toxicity. Although reporter-gene technology is in its infancy, with further refinement reporter animals could become a valuable tool in the early stages of target and lead identification and preclinical drug development
A new synthesis of 2-cyano-6-hydroxybenzothiazole, the key intermediate of D-luciferin, starting from 1,4-benzoquinone
No full text2-cyano-6-hydroxybenzothiazole is the key intermediate for the synthesis of D-luciferin, the natural substrate of firefly luciferases. A new synthesis of 2-cyano-6-hydroxybenzothiazole has been realized starting from the reaction of 1,4-benzoquinone with L-cysteine ethyl ester, followed by an oxidation-cyclization of the intermediate ethyl (R)-2-amino-3-(2,5-dihydroxyphenylsulfanyl)propanoate hydrochloride to 2-carbethoxy-6-hydroxybenzothiazole. A suitable protection of this intermediate and a conversion to the corresponding nitrile gave, after deprotection, 2-cyano-6-hydroxybenzothiazole (32% yield from 1,4-benzoquinone). This nitrile reacts with D-cysteine to afford D-luciferin at room temperature in a nearly quantitative yield (90-95%)
17beta-estradiol inhibits inflammatory gene expression by controlling NF-kB intracellular localization
No full textEstrogen is an immunoregulatory agent, in that hormone deprivation increases while 17ß-estradiol (E2) administration blocks the inflammatory response; however, the underlying mechanism is still unknown. The transcription factor p65/relA, a member of the nuclear factor kB (NF-kB) family, plays a major role in inflammation and drives the expression of proinflammatory mediators. Here we report a novel mechanism of action of E2 in inflammation. We observe that in macrophages E2 blocks lipopolysaccharide-induced DNA binding and transcriptional activity of p65 by preventing its nuclear translocation. This effect is selectively activated in macrophages to prevent p65 activation by inflammatory agents and extends to other members of the NF-kB family, including c-Rel and p50. We observe that E2 activates a rapid and persistent response that involves the activation of phosphatidylinositol 3-kinase, without requiring de novo protein synthesis or modifying Ik-Ba degradation and mitogen-activated protein kinase activation. Using a time course experiment and the microtubule-disrupting agent nocodazole, we observe that the hormone inhibits p65 intracellular transport to the nucleus. This activity is selectively mediated by estrogen receptor alpha (ERa) and not ERb and is not shared by conventional anti-inflammatory drugs. These results unravel a novel and unique mechanism for E2 anti-inflammatory activity, which may be useful for identifying more selective ligands for the prevention of the inflammatory response
Estrogen anti-inflammatory activity in brain: a therapeutic opportunity for menopause and neurodegenerative diseases
Full text linkRecent studies highlight the prominent role played by estrogens in protecting the central nervous system (CNS) against the noxious consequences of a chronic inflammatory reaction. The neurodegenerative process of several CNS diseases, including Multiple Sclerosis, Alzheimer's and Parkinson's Diseases, is associated with the activation of microglia cells, which drive the resident inflammatory response. Chronically stimulated during neurodegeneration, microglia cells are thought to provide detrimental effects on surrounding neurons. The inhibitory activity of estrogens on neuroinflammation and specifically on microglia might thus be considered as a beneficial therapeutic opportunity for delaying the onset or progression of neurodegenerative diseases; in addition, understanding the peculiar activity of this female hormone on inflammatory signalling pathways will possibly lead to the development of selected anti-inflammatory molecules. This review summarises the evidence for the involvement of microglia in neuroinflammation and the anti-inflammatory activity played by estrogens specifically in microglia
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