Phenylphenols,biphenols, bisphenol-A and 4-tert-octylphenol exhibit alpha and beta estrogen activities and antiandrogen activity in reporter cell lines

We previously demonstrated the interactions of different chemical compounds with estrogen receptors ERalpha and ERbeta and the androgen receptor (AR) using different reporter cell lines. In this study, we characterize the ERalpha, ERbeta and AR activity of different biphenyls using the same tools. We provide evidence that several phenyl derivatives present both estrogenic and antiandrogenic activity. The extent of hydroxylation and the position of the hydroxyl function were important in determining their estrogenicity and antiandrogenicity. Of the tested compounds, bisphenol-A and 4,4' biphenol had very high estrogenic activity, although it was lower than that of the strong estrogenic alkylphenol, 4-tert-octylphenol. Bisphenol-A and 4,4' biphenol were able to activate ERs at concentrations lower than 1 microM, whereas the other compounds only activated at concentrations above 1 microM. Interestingly, 4,4' biphenol was a better agonist for ERbeta than for ERalpha. No androgenic activity was detected for any of these compounds. Bisphenol-A, 3-OH phenylphenol, 4-OH phenylphenol and 4,4' biphenol exhibited antiandrogenic activity close to that of 4-tert-octylphenol (IC(50) approximately 5 microM). In whole cell binding assays, these compounds displaced [3H] R1881 with Ki = 10 microM. Although these Ki values seem high in comparison with that of hydroxyflutamide (0.4 microM), one must keep in mind that environmental chemicals can accumulate in adipose tissues for several years. In conclusion, these environmental chemicals may have a negative impact on androgen action during fetal and post-natal life.     

Long-term protective effect of post-exposure Havrix TM administration during viral hepatitis Type A outbreaks

Administration of human normal immunoglobulin (HNIG) post-exposure has been routinely used in Slovakia for outbreak control of hepatitis A, but requires deep intramuscular injection, provides only short-lived protection and is a human blood product. The protective effect of post-exposure administration of an inactivated hepatitis A vaccine was evaluated during 10 outbreaks in Slovakia. Direct contacts of confirmed hepatitis A cases received either: a single dose of hepatitis A vaccine (n = 2171) or immunoglobulin (HNIG, n = 3837). In the HNIG group the number of hepatitis A confirmed cases dropped within the first 7 weeks, however the decrease was not as rapid or as marked as that observed in the vaccinated group where the number of hepatitis A cases dropped within the first 4 weeks after vaccination. Among contacts, 67 cases of hepatitis A were detected during the maximum incubation period of 45 days: 16 cases (0.7%) in the vaccine group and 51 cases (1.3%) in the HNIG group (p  <  0.05). After two and three years respectively, 50 and 39 volunteers who had previously received one dose of hepatitis A vaccine received a booster dose and anti-HAV antibodies were measured. Differences in anti-HAV antibody GMCs before and after the booster were statistically significant. The longer time interval (3 years instead of 2) between primary vaccination and booster administration did not seem to impact the magnitude of the booster response. The results of this study show that active post-exposure immunisation with only one dose of inactivated vaccine confers high and long-term protection and effectively controls viral hepatitis A outbreaks.     

A prognostic DNA signature for T1T2 node‐negative breast cancer patients

Predicting evolution of small node‐negative breast carcinoma is a real challenge in clinical practice. The aim of this study was to search whether qualitative or quantitative DNA changes may help to predict metastasis of small node‐negative breast carcinoma. Small invasive ductal carcinomas without axillary lymph node involvement (T1T2N0) from 168 patients with either good (111 patients with no event at 5 years after diagnosis) or poor (57 patients with early metastasis) outcome were analyzed with comparative genomic hybridization (CGH) array. A CGH classifier, identifying low‐ and high‐risk groups of metastatic recurrence, was established in a training set of 78 patients, then validated, and compared with clinicopathological parameters in a distinct set of 90 patients. The genomic status of regions located on 2p22.2, 3p23, and 8q21‐24 and the number of segmental alterations were defined in the training set to classify tumors into low‐ or high‐risk groups. In the validation set, in addition to estrogen receptors and grade, this CGH classifier provided significant prognostic information in multivariate analysis (odds ratio, 3.34; 95% confidence interval 1.01–11.02; P = 4.78 × 10^?2, Wald test). This study shows that tumor DNA contains important prognostic information that may help to predict metastasis in T1T2N0 tumors of the breast. © 2010 Wiley‐Liss, Inc.     

Retinoic acid metabolism and signaling pathways in the adult and developing mouse testis

As a first step in investigating the role of retinoic acid (RA) in mouse testis, we analyzed the distribution pattern of the enzymes involved in vitamin A storage (lecithin:retinol acyltransferase), RA synthesis (beta-carotene 15,15'-monoxygenase and retinaldehyde dehydrogenases) and RA degradation (cytochrome P450 hydroxylases) as well as those of all isotypes of receptors transducing the RA signal [RA receptors (RARs) and rexinoid receptors (RXRs)]. Our data indicate that in adult testis 1) cytochrome P450 hydroxylase enzymes may generate in peritubular myoid cells a catabolic barrier that prevents circulating RA and RA synthesized by Leydig cells to enter the seminiferous epithelium; 2) the compartmentalization of RA synthesis within this epithelium may modulate, through paracrine mechanisms, the coupling between spermatogonia proliferation and spermatogenesis; 3) retinyl esters synthesized in round spermatids by lecithin:retinol acyltransferase may be transferred and stored in Sertoli cells, in the form of adipose differentiation-related protein-coated lipid droplets. We also show that RARalpha and RXRbeta are confined to Sertoli cells, whereas RARgamma is expressed in spermatogonia and RARbeta, RXRalpha, and RXRgamma are colocalized in step 7-8 spermatids. Correlating these expression patterns with the pathological phenotypes generated in response to RAR and RXR mutations and to postnatal vitamin A deficiency suggests that spermiation requires RXRbeta/RARalpha heterodimers in Sertoli cells, whereas spermatogonia proliferation involves, independently of RXR, two distinct RAR-mediated signaling pathways in both Sertoli cells and spermatogonia. Our data also suggest that the involvement of RA in testis development starts when primary spermatogonia first appear.     

Implication of 5-HT2A subtype receptors in DOI activity in the four-plates test-retest paradigm in mice

The four-plates test (FPT) is an animal model of anxiety which allows the detection of anxiolytic effect not only of benzodiazepines (BZDs) but also of other non-BZDs anxiolytic compounds such as antidepressants (ADs). Furthermore, DOI, a 5-HT(2A/2C) agonist, has been shown to exert an anxiolytic-like effect in this model. Retesting mice in animal models of anxiety (test-retest paradigm) induces an anxiogenic-like and a loss of anxiolytic-like effects in response to BZDs and ADs. On the contrary, DOI has been reported to oppose the fear potentiation induced by trial 1 in the FPT. Despite DOI is considered as one of the most selective 5-HT(2A) available, it acts as agonist at all three 5-HT(2) receptor subtypes (5-HT(2A), 5-HT(2B) and 5-HT(2C)). The aim of this study was thus to investigate in the FPT test-retest paradigm, which 5-HT(2) receptor subtype(s) was involved in the DOI-induced effect in experienced mice. The effect of DOI (0.25-4 mg/kg) and the agonists, 5-HT(2B), BW 723C86 (1-16 mg/kg) and 5-HT(2C), RO 60-0175 (0.25-4 mg/kg) have also been studied. Then, antagonism studies were conducted combinating the 5-HT(2A) receptor antagonist SR 46349B, the 5-HT(2B/2C) receptor antagonist SB 206553 or the selective 5-HT(2C) receptor antagonist RS 10-2221 (at the doses of 0.1 and 1 mg/kg) with the DOI (1 mg/kg). Our study shows that the BW 723C86 had no effect on retesting mice, whereas it exerted an anxiolytic-like effect in naive mice. By contrast to DOI, the RO 60-0175 had no effect neither in naive nor experienced mice. Furthermore, only the SR 46349B antagonized the DOI-induced anti-punishment effect. Diazepam included as a positive control also increased in each case the number of punished passages in naive mice. Our findings altogether also suggest that DOI exerts its anxiolytic-like effect in the FPT test-retest paradigm through 5-HT(2A) receptors.     

Enhancement of social novelty discrimination by positive allosteric modulators at metabotropic glutamate 5 receptors: adolescent administration prevents adult-onset deficits induced by neonatal treatment with phencyclidine

Metabotropic glutamate-5 receptors (mGluR5), which physically and functionally interact with N-methyl-d-Aspartate (NMDA) receptors, likewise control cognitive processes and have been proposed as targets for novel classes of antipsychotic agent. Since social cognition is impaired in schizophrenia and disrupted by NMDA receptor antagonists like dizocilpine, we evaluated its potential modulation by mGluR5. Acute administration (0.63–40 mg/kg) of the mGluR5 positive allosteric modulators (PAMs), 3-cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide (CDPPB) and ADX47273, reversed a delay-induced impairment in social novelty discrimination (SND) in adult rats. The action of CDPPB was blocked by the mGluR5 antagonist, 2-methyl-6-(phenylethynyl)-pyridine (2.5–10 mg/kg), and was also expressed upon microinjection into frontal cortex (0.63–10 μg/side), but not striatum. Supporting an interrelationship between mGluR5 and NMDA receptors, enhancement of SND by CDPPB was blocked by dizocilpine (0.08 mg/kg) while, reciprocally, dizocilpine-induced impairment in SND was attenuated by CDPPB (10 mg/kg). The SND deficit elicited by post-natal administration of phencyclidine (10 mg/kg, days?7–11) was reversed by CDPPB or ADX47273 in adults at week?8. This phencyclidine-induced impairment in cognition emerged in adult rats from week?7 on, and chronic, pre-symptomatic treatment of adolescent rats with CDPPB over weeks?5–6 (10 mg/kg per day) prevented the appearance of SND deficits in adults until at least week?13. In conclusion, as evaluated by a SND procedure, mGluR5 PAMs promote social cognition via actions expressed in interaction with NMDA receptors and exerted in frontal cortex. MGluR5 PAMs not only reverse but also (when given during adolescence) prevent the emergence of cognitive impairment associated with a developmental model of schizophrenia.     

The in vivo mitochondrial two-step maturation of human frataxin

Deficiency in the nuclear-encoded mitochondrial protein frataxin causes Friedreich ataxia (FRDA), a progressive neurodegenerative disorder associating spinocerebellar ataxia and cardiomyopathy. Although the exact function of frataxin is still a matter of debate, it is widely accepted that frataxin is a mitochondrial iron chaperone involved in iron-sulfur cluster and heme biosynthesis. Frataxin is synthesized as a precursor polypeptide, directed to the mitochondrial matrix where it is proteolytically cleaved by the mitochondrial processing peptidase to the mature form via a processing intermediate. The mature form was initially reported to be encoded by amino acids 56-210 (m(56)-FXN). However, two independent reports have challenged these studies describing two different forms encoded by amino acids 78-210 (m(78)-FXN) and 81-210 (m(81)-FXN). Here, we provide evidence that mature human frataxin corresponds to m(81)-FXN, and can rescue the lethal phenotype of fibroblasts completely deleted for frataxin. Furthermore, our data demonstrate that the migration profile of frataxin depends on the experimental conditions, a behavior which most likely contributed to the confusion concerning the endogenous mature frataxin. Interestingly, we show that m(56)-FXN and m(78)-FXN can be generated when the normal maturation process of frataxin is impaired, although the physiological relevance is not clear. Furthermore, we determine that the d-FXN form, previously reported to be a degradation product, corresponds to m(78)-FXN. Finally, we demonstrate that all frataxin isoforms are generated and localized within the mitochondria. The clear identification of the N-terminus of mature FXN is an important step for designing therapeutic approaches for FRDA based on frataxin replacement.     

Antinociceptive effect of peripheral serotonin 5-HT2B receptor activation on neuropathic pain

Serotonin is critically involved in neuropathic pain. However, its role is far from being understood owing to the number of cellular targets and receptor subtypes involved. In a rat model of neuropathic pain evoked by chronic constriction injury (CCI) of the sciatic nerve, we studied the role of 5-HT(2B) receptor in dorsal root ganglia (DRG) and the sciatic nerve. We showed that 5-HT(2B) receptor activation both prevents and reduces CCI-induced allodynia. Intrathecal administration of 5-HT(2B) receptor agonist BW723C86 significantly attenuated established mechanical and cold allodynia; this effect was prevented by co-injection of RS127445, a selective 5-HT(2B) receptor antagonist. A single application of BW723C86 on the sciatic nerve concomitantly to CCI dose-dependently prevented mechanical allodynia and significantly reduced cold allodynia 17 days after CCI. This behavioral effect was accompanied with a marked decrease in macrophage infiltration into the sciatic nerve and, in the DRG, with an attenuated abnormal expression of several markers associated with local neuroinflammation and neuropathic pain. CCI resulted in a marked upregulation of 5-HT(2B) receptor expression in sciatic nerve and DRG. In the latter structure, it was biphasic, consisting of a transient early increase (23-fold), 2 days after the surgery and before the neuropathic pain emergence, followed by a steady (5-fold) increase, that remained constant until pain disappeared. In DRG and sciatic nerve, 5-HT(2B) receptors were immunolocalized on sensory neurons and infiltrating macrophages. Our data reveal a relationship between serotonin, immunocytes, and neuropathic pain development, and demonstrate a critical role of 5-HT(2B) receptors in blood-derived macrophages.     

Alu-mediated deletion of SOX10 regulatory elements in Waardenburg syndrome type 4

Waardenburg syndrome type 4 (WS4) is a rare neural crest disorder defined by the combination of Waardenburg syndrome (sensorineural hearing loss and pigmentation defects) and Hirschsprung disease (intestinal aganglionosis). Three genes are known to be involved in this syndrome, that is, EDN3 (endothelin-3), EDNRB (endothelin receptor type B), and SOX10. However, 15-35% of WS4 remains unexplained at the molecular level, suggesting that other genes could be involved and/or that mutations within known genes may have escaped previous screenings. Here, we searched for deletions within recently identified SOX10 regulatory sequences and describe the first characterization of a WS4 patient presenting with a large deletion encompassing three of these enhancers. Analysis of the breakpoint region suggests a complex rearrangement involving three Alu sequences that could be mediated by a FosTes/MMBIR replication mechanism. Taken together with recent reports, our results demonstrate that the disruption of highly conserved non-coding elements located within or at a long distance from the coding sequences of key genes can result in several neurocristopathies. This opens up new routes to the molecular dissection of neural crest disorders.