Inflammatory role of ASC in antigen-induced arthritis is independent of caspase-1, NALP-3, and IPAF.

Because IL-1beta plays an important role in inflammation in human and murine arthritis, we investigated the contribution of the inflammasome components ASC, NALP-3, IPAF, and caspase-1 to inflammatory arthritis. We first studied the phenotype of ASC-deficient and wild-type mice during Ag-induced arthritis (AIA). ASC(-/-) mice showed reduced severity of AIA, decreased levels of synovial IL-1beta, and diminished serum amyloid A levels. In contrast, mice deficient in NALP-3, IPAF, or caspase-1 did not show any alteration of joint inflammation, thus indicating that ASC associated effects on AIA are independent of the classical NALP-3 or IPAF inflammasomes. Because ASC is a ubiquitous cytoplasmic protein that has been implicated in multiple cellular processes, we explored other pathways through which ASC may modulate inflammation. Ag-specific proliferation of lymph node and spleen cells from ASC-deficient mice was significantly decreased in vitro, as was the production of IFN-gamma, whereas IL-10 production was enhanced. TCR ligation by anti-CD3 Abs in the presence or absence of anti-CD28 Abs induced a reduction in T cell proliferation in ASC(-/-) T cells compared with wild-type ones. In vivo lymph node cell proliferation was also significantly decreased in ASC(-/-) mice, but no effects on apoptosis were observed either in vitro or in vivo in these mice. In conclusion, these results strongly suggest that ASC modulates joint inflammation in AIA through its effects on cell-mediated immune responses but not via its implication in inflammasome formation.

Diagnosing lung cancer using etoposide microparticles labeled with 99mTc.

The diagnosis of lung cancer mostly occurs when the cancer is already in an advanced stage. In this situation, there are few options for the treatment and most of them have few chances of success. In this study, we developed and tested etoposide microparticles as a diagnostic agent for imaging lung cancer at early stages of development. We tested etoposide microparticles labeled with technetium 99m in inducted mice. The results demonstrated that over 10% of the total dose used was uptake by the tumor site. Also, the results showed that the microparticles had a good renal clearance and low uptake by liver and spleen. The data suggest that these micro-radiopharmaceuticals may be used for lung cancer imaging exam, especially single-photo emission computed tomography (SPECT).[Formula: see text].

Metformin inhibits adenosine 5'-monophosphate-activated kinase activation and prevents increases in neuropeptide Y expression in cultured hypothalamic neurons.

The oral antidiabetic agent metformin acts at least partially via an activation of AMP-activated kinase (AMPK) in liver and muscle cells. It has appeared recently that hypothalamic AMPK is a key regulator of feeding in mammals. Because metformin also exhibits anorectic effects in animal models as well as in humans, we hypothesized that AMPK may be a target of metformin in hypothalamic neurons. In this study, we show that, in primary cultures of rat hypothalamic neurons, low glucose levels stimulate the phosphorylation of AMPK, thus increasing neuropeptide Y (NPY) gene expression. The addition of metformin in low glucose conditions was found to block AMPK phosphorylation. Consistently, the stimulation of NPY observed in low glucose conditions was also inhibited by the drug. Proopiomelanocortin gene expression measured in parallel was inhibited under low glucose conditions, but in contrast to NPY, it was not dependent upon AMPK and not affected by metformin. Taken together, our data demonstrate that metformin can inhibit AMPK activity in hypothalamic neurons, thus modulating the expression of the orexigenic peptide NPY. These results provide, for the first time, a potential mechanism of action for the anorectic effects of metformin, a widely used drug that could represent a valuable adjunct to novel therapies aimed at modulating central feeding pathways.

Hypogonadism in a patient with a mutation in the luteinizing hormone beta-subunit gene.

A 30-year-old man who presented with delayed puberty and infertility was found to have hypogonadism associated with an absence of circulating luteinizing hormone. The patient had a homozygous missense mutation in the gene that encodes the beta subunit of luteinizing hormone (Gly36Asp), a mutation that disrupted a vital cystine knot motif and abrogated the heterodimerization and secretion of luteinizing hormone. Treatment with human chorionic gonadotropin increased circulating testosterone, promoted virilization, and was associated with the appearance of normal spermatozoa in low concentrations. This case illustrates the important physiological role that luteinizing hormone plays in male sexual maturation and fertility.

Effects of cytokines on gonadotropin-releasing hormone (GnRH) gene expression in primary hypothalamic neurons and in GnRH neurons immortalized conditionally.

Various cytokines produced during the immune reaction can modulate the neuroendocrine reproductive axis, probably by inducing changes in the activity of hypothalamic GnRH neurons. However, the precise cellular and molecular effects of cytokines on these neurons have not been reported yet. To gain a better insight into these regulations, we first examined the pattern of expression of cytokine receptors in a novel neuronal cell line expressing GnRH (Gnv-4 cells). Among others, gp130 is expressed in Gnv-4 cells, together with the ligand receptor subunits specific for IL-6 as well as oncostatin M (OSM). Consistent with the latter observation, we show that OSM stimulates the expression of the immediate early genes c-fos and early growth response-1 in Gnv-4 cells, an effect dependent upon the activation of the MAPK Erk1/2 intracellular signaling pathway. Functional studies performed in parallel in Gnv-4 cells and in primary hypothalamic neuronal cell cultures show that OSM, although devoid of any effect of its own on GnRH gene expression, can inhibit dose-dependently the stimulation of GnRH expression by N-methyl-d-aspartic acid. In conclusion, these data demonstrate that a GnRH-expressing neuronal cell line can be modulated in vitro by cytokines implicated in the regulation of the reproductive axis. Moreover, they provide the first evidence of an involvement of OSM in these regulations.

Gonadotropin-releasing hormone-expressing neurons immortalized conditionally are activated by insulin: implication of the mitogen-activated protein kinase pathway.

Energy balance exerts a critical influence on reproduction via changes in the circulating levels of hormones such as insulin. This modulation of the neuroendocrine reproductive axis ultimately involves variations in the activity of hypothalamic neurons expressing GnRH. Here we studied the effects of insulin in primary hypothalamic cell cultures as well as a GnRH neuronal cell line that we generated by conditional immortalization of adult hypothalamic neurons. These cells, which represent the first successful conditional immortalization of GnRH neurons, retain many of their mature phenotypic characteristics. In addition, we show that they express the insulin receptor. Consistently, their stimulation with insulin activates both the phosphatidylinositol 3-kinase and the Erk1/2 MAPK signaling pathways and stimulates a rapid increase in the expression of c-fos, demonstrating their responsiveness to this hormone. Further work performed in parallel in immortalized GnRH-expressing cells and primary neuronal cultures containing non-GnRH-expressing neurons shows that insulin induces the expression of GnRH in both models. In primary cultures, inhibition of the Erk1/2 pathway abolishes the stimulation of GnRH expression by insulin, whereas blockade of the phosphatidylinositol 3-kinase pathway has no effect. In conclusion, these data strongly suggest that GnRH neurons are directly sensitive to insulin and implicate for the first time the MAPK Erk1/2 signaling pathway in the central effects of insulin on the neuroendocrine reproductive axis.

Impaired histone deacetylases 5 and 6 expression mimics the effects of obesity and hypoxia on adipocyte function.

OBJECTIVE: The goal of the study was to investigate the role of histone deacetylases (HDACs) in adipocyte function associated with obesity and hypoxia. METHODS: Total proteins and RNA were prepared from human visceral adipose tissues (VAT) of human obese and normal weight subjects and from white adipose tissue (WAT) of C57Bl6-Rj mice fed a normal or high fat diet (HFD) for 16 weeks. HDAC activity was measured by colorimetric assay whereas the gene and protein expression were monitored by real-time PCR and by western blotting, respectively. RNA interference (RNAi) was used to silence the expression of genes in 3T3-L1 adipocytes. RESULTS: Total HDAC activity was decreased in VAT and WAT from obese individuals and from mice fed a HFD, respectively. The HDAC activity reduction was associated with decreased HDAC5/Hdac5 and HDAC6/Hdac6 expression in human and mice adipocyte fraction. Similarly, hypoxia hampered total Hdac activity and reduced the expression of Hdac5 and Hdac6 in 3T3-L1 adipocytes. The decrease of both Hdac5 and Hdac6 by hypoxia was associated with altered expression of adipokines and of the inducible cAMP early repressor (Icer), a key repressor that is defective in human and mice obesity. Silencing of Icer in adipocytes reproduced the changes in adipokine levels under hypoxia and obesity, suggesting a causative effect. Finally, modeling the defect of the two Hdacs in adipocytes by RNAi or selective inhibitors mimicked the effects of hypoxia on the expression of Icer, leading to impairment of insulin-induced glucose uptake. CONCLUSION: Hdac5 and Hdac6 expression are required for the adequate expression of Icer and adipocyte function. Altered adipose expression of the two Hdacs in obesity by hypoxia may contribute to the development of metabolic abnormalities.

Progressive onset of adrenal insufficiency and hypogonadism of pituitary origin caused by a complex genetic rearrangement within DAX-1.

DAX-1 [dosage-sensitive sex reversal, adrenal hypoplasia congenital (AHC) critical region on the X chromosome, gene 1] is a transcription factor expressed in the adrenal gland and at all levels of the gonadotrope axis. Inactivating mutations of DAX1 result in the X-linked form of AHC with associated hypogonadotropic hypogonadism. AHC usually reveals itself as adrenal failure in early infancy, although a wide range of phenotypic expression has been reported. We describe a patient who was diagnosed with adrenal failure at 6 wk of age, but who experienced recovery of adrenal function of several months' duration later in infancy. He subsequently failed to undergo puberty because of hypogonadotropic hypogonadism of pituitary origin, and he was also diagnosed with schizophrenia in early adulthood. Molecular genetic analyses revealed a complex rearrangement in DAX1, including a 2.2-kb deletion spanning the entire second exon and a small 27-bp insertion. The putative protein encoded by this mutated gene is 429 amino acids long. The initial 389 residues probably correspond to the wild-type DAX-1 sequence, whereas the last 40 amino acids are presumably completely unrelated, being transcribed from the intronic sequence adjacent to exon 1. In vitro functional analyses confirm the absence of repressor activity exerted by such mutant protein. These studies expand the genotypic and phenotypic spectrum of DAX-1 insufficiency in humans.

Decompensation of ß-cells in diabetes: when pancreatic ß-cells are on ICE(R).

Insulin production and secretion are temporally regulated. Keeping insulin secretion at rest after a rise of glucose prevents exhaustion and ultimately failure of ß-cells. Among the mechanisms that reduce ß-cell activity is the inducible cAMP early repressor (ICER). ICER is an immediate early gene, which is rapidly induced by the cyclic AMP (cAMP) signaling cascade. The seminal function of ICER is to negatively regulate the production and secretion of insulin by repressing the genes expression. This is part of adaptive response required for proper ß-cells function in response to environmental factors. Inappropriate induction of ICER accounts for pancreatic ß-cells dysfunction and ultimately death elicited by chronic hyperglycemia, fatty acids, and oxidized LDL. This review underlines the importance of balancing the negative regulation achieved by ICER for preserving ß-cell function and survival in diabetes.

Identification of relevant conformational epitopes on the HER2 oncoprotein by using Large Fragment Phage Display (LFPD).

We developed a new phage-display based approach, the Large Fragment Phage Display (LFPD), that can be used for mapping conformational epitopes on target molecules of immunological interest. LFPD uses a simplified and more effective phage-display approach in which only a limited set of larger fragments (about 100 aa in length) are expressed on the phage surface. Using the human HER2 oncoprotein as a target, we identified novel B-cell conformational epitopes. The same homologous epitopes were also detected in rat HER2 and all corresponded to the epitopes predicted by computational analysis (PEPITO software), showing that LFPD gives reproducible and accurate results. Interestingly, these newly identified HER2 epitopes seem to be crucial for an effective immune response against HER2-overexpressing breast cancers and might help discriminating between metastatic breast cancer and early breast cancer patients. Overall, the results obtained in this study demonstrated the utility of LFPD and its potential application to the detection of conformational epitopes on many other molecules of interest, as well as, the development of new and potentially more effective B-cell conformational epitopes based vaccines.

Evidence for tuning adipocytes ICER levels for obesity care.

Abnormal adipokine production, along with defective uptake and metabolism of glucose within adipocytes, contributes to insulin resistance and altered glucose homeostasis. Recent research has highlighted one of the mechanisms that accounts for impaired production of adiponectin (ADIPOQ) and adipocyte glucose uptake in obesity. In adipocytes of human obese subjects and mice fed with a high fat diet, the level of the inducible cAMP early repressor (ICER) is diminished. Reduction of ICER elevates the cAMP response element binding protein (CREB) activity, which in turn increases the repressor activating transcription factor 3. In fine, the cascade triggers reduction in the ADIPOQ and GLUT4 levels, which ultimately hampers insulin-mediated glucose uptake. The c-Jun N-terminal kinase (JNK) interacting-protein 1, also called islet brain 1 (IB1), is a target of CREB/ICER that promotes JNK-mediated insulin resistance in adipocytes. A rise in IB1 and c-Jun levels accompanies the drop of ICER in white adipose tissues of obese mice when compared with mice fed with a chow diet. Other than the expression of ADIPOQ and glucose transport, decline in ICER expression might impact insulin signaling. Impairment of ICER is a critical issue that will need major consideration in future therapeutic purposes.

Molecular characterization and phenotypic expression of mutations in genes for gonadotropins and their receptors in humans.

Gonadotropin hormones undergo important dynamic changes during life. Their rise during puberty stimulates gonadal steroid secretion, triggering the development of secondary sexual characteristics and the acquisition of fertility. The full spectrum of possible mutations and polymorphisms in the human gonadotropins and in their receptor genes has been described in recent years. Patients harboring these mutations display a very wide range of phenotypes affecting all aspects of the reproductive axis. An important insight provided by the careful study of these patients lies in the striking gender differences in the phenotypes associated with a given mutation. As a result, the careful study of these rare patients has allowed us to better define the respective roles of luteinizing hormone and follicle-stimulating hormone in normal human pubertal development and in the achievement of full fertility potential in either males or females. In this work, we describe briefly the known mutations in the genes for both gonadotropins and their receptors, and discuss their genotype/phenotype correlations in light of these important gender differences.

The fetal hypothalamus has the potential to generate cells with a gonadotropin releasing hormone (GnRH) phenotype.

BACKGROUND: Neurospheres (NS) are colonies of neural stem and precursor cells capable of differentiating into the central nervous system (CNS) cell lineages upon appropriate culture conditions: neurons, and glial cells. NS were originally derived from the embryonic and adult mouse striatum subventricular zone. More recently, experimental evidence substantiated the isolation of NS from almost any region of the CNS, including the hypothalamus. METHODOLOGY/FINDINGS: Here we report a protocol that enables to generate large quantities of NS from both fetal and adult rat hypothalami. We found that either FGF-2 or EGF were capable of inducing NS formation from fetal hypothalamic cultures, but that only FGF-2 is effective in the adult cultures. The hypothalamic-derived NS are capable of differentiating into neurons and glial cells and most notably, as demonstrated by immunocytochemical detection with a specific anti-GnRH antibody, the fetal cultures contain cells that exhibit a GnRH phenotype upon differentiation. CONCLUSIONS/SIGNIFICANCE: This in vitro model should be useful to study the molecular mechanisms involved in GnRH neuronal differentiation.

Importance of genetic diagnosis of DAX-1 deficiency: example from a large, multigenerational family.

BACKGROUND: Inactivating mutations of DAX-1 give rise to the X-linked form of adrenal hypoplasia congenita (AHC). Affected fetuses are at risk of early postnatal Addisonian crisis, but the variable phenotypic expression of DAX-1 insufficiency renders this diagnosis challenging. METHODS: We describe the familial transmission of AHC over several generations. The proband was diagnosed with adrenal insufficiency at age 3.5 years: molecular analysis revealed a novel, 373-bp deletion including the second exon of DAX-1. Given the familial history of several unexplained deaths in male infants related to the proband via his maternal great-grandmother, we hypothesized that all these boys had been affected with AHC. Another female member of the family being pregnant with a male fetus at the time, we performed DAX-1 analysis on the mother and the newborn. The mother was heterozygous for the deletion, and the newborn hemizygous: he presented an adrenal crisis at 10 days of life, and is now doing well on hormone replacement therapy. CONCLUSION: The unfortunate deaths of male infants at each generation of this family underlie the importance of early and precise diagnosis of this rare condition, stressing the value of genetic diagnosis in six potential female carriers of this family entering their reproductive years.

Role of the tissue factor pathway in synovial inflammation.

OBJECTIVE: Clinical and experimental evidence suggests that extravascular fibrin deposition in arthritic joints is prominent and deleterious. The aim of this study was to investigate the contributions of tissue factor (TF) and its inhibitor, TF pathway inhibitor (TFPI), in arthritis. METHODS: Synovial tissue specimens obtained from 10 patients with rheumatoid arthritis (RA) and 12 patients with osteoarthritis (OA) were scored histologically for inflammation and fibrin content. TF and TFPI levels were assayed at antigenic and functional levels. TF messenger RNA (mRNA) levels were determined using RNase protection assays. The effect of TF inhibition in murine antigen-induced arthritis (AIA) was assessed by administering systemically active site-blocked activated factor VIIa (FVIIai). RESULTS: Functional TF activity was significantly increased in synovial membranes from RA patients compared with those from OA patients. In contrast, no difference in TF mRNA and TF antigenic levels was observed between these 2 groups. This discrepancy can be accounted for by TFPI, because we observed a negative correlation between TF activity and TFPI activity. There was a significant difference between the RA and OA groups in terms of synovial inflammation, with more inflammation observed in the RA group. Most importantly, TF activity was associated with fibrin (P = 0.024) and with histologic inflammation (P = 0.03) scores. In AIA, inhibition of TF-induced coagulation by FVIIai led, on day 9 of arthritis, to decreased synovial thickness and decreased articular cartilage damage, although only the latter difference between controls and treated mice reached significance (P < 0.04). Finally, in FVIIai-treated mice, there was a strong negative association between the prothrombin time and intraarticular fibrin deposition. CONCLUSION: Our results show that TF expression in arthritic synovial tissue favors extravascular coagulation and may play a role in inflammation in RA. In this context, TF inhibitors may be of therapeutic value.

Radiofarmácia e radiofármacos no Brasil: aspectos sanitários e fabris para a construção de uma linha de produção de radiofármacos PET / Radiopharmacy and radiopharmaceuticals in Brazil: sanitaries aspects related to a project of an industry of PET radiopharmaceuticals

O aumento do uso de radiofármacos PET (Pósitron Emission Tomography) vem chamando a atenção dos profissionais da área de Medicina Nuclear e Farmácia, assim como das agências reguladoras. O objetivo é prover parâmetros estruturais e legais mínimos como uma referência nacional em radiofarmácia, que possam auxiliar as agências regulatórias, focando principalmente no projeto fabril.

The increasing use of radiopharmaceuticals for PET (Positron Emission Tomography) has come to the attention of nuclear medicine staff and regulatory bodies. The aim of this study is to provide a national reference in radiopharmacy that could help all nuclear medicine staff and specially the Brazilian's regulatory bodies focused on the industrial project.