Estradiol-regulated expression of the immunophilins cyclophilin 40 and FKBP52 in MCF-7 breast cancer cells

The immunophilins, cyclophilin 40 (CyP40) and FKBP52, are associated with the unactivated estrogen receptor in mutually exclusive heterocomplexes and may differentially modulate receptor activity, We have recently shown that CyP40 and FKBP52 mRNA's are differentially elevated in breast carcinomas compared with normal breast tissue. Other studies suggest that such alterations ill the ratio of immunophilins might potentially influence steroid receptor function. Studies were therefore initiated to investigate the influence of estradiol on CyP40 and FKBP52 expression in MCF-7 breast cancer cells. Over a 24-h-treatment period with estradiol, CyP40 and FKBP52 mRNA expression was increased approximately five- and 14-fold, respectively. The corresponding protein levels were also elevated in comparison to controls. The antiestrogen, ICI 182,780, was an antagonist for CyP40 and FKBP52 mRNA induction. Cycloheximide treatment did not inhibit this increased immunophilin expression, suggesting that estradiol-mediated activation is independent off de novo protein synthesis. Treatment of MCF-7 cells with estradiol resulted in an increased half-life of both CyP40 and FKBP52 mRNA, as determined by actinomycin D studies. These results suggest that estradiol regulates CyP40 and FKBP52 mRNA expression through both transcriptional and posttranscriptional mechanisms. (C) 2001 Academic Press.

Nuclear localization of RelB is associated with effective antigen-presenting cell function

Dendritic cells (DC) are potent APCs that enter resting tissues as precursors and, after Ag exposure, differentiate and migrate to draining lymph nodes. The phenotype of RelB knockout mice implicates this member of the NF kappa B/Rel family in DC differentiation. To further elucidate the role of RelB in DC differentiation, mRNA, intracellular protein expression, and DNA binding activity of RelB were examined in immature and differentiated human DC, as well as other PB mononuclear cell populations. RelB protein and mRNA were detected constitutively in lymphocytes and in activated monocytes, differentiated DC, and monocyte-derived DC. Immunohistochemical staining demonstrated RelB within the differentiated lymph node interdigitating DC and follicular DC, but not undifferentiated DC in normal skin. Active nuclear RelB was detected by supershift assay only in differentiated DC derived from either PB precursors or monocytes and in activated B cells. These RelB+ APC were potent stimulators of the MLR. The data indicate that RelB expression is regulated both transcriptionally and post-translationally in myeloid cells. Within the nucleus, RelB may specifically transactivate genes that are critical for APC function.

Nuclear localization of RelB is associated with effective antigen-presenting cell function

Dendritic cells (DC) are potent APCs that enter resting tissues as precursors and, after Ag exposure, differentiate and migrate to draining lymph nodes. The phenotype of RelB knockout mice implicates this member of the NF kappa B/Rel family in DC differentiation. To further elucidate the role of RelB in DC differentiation, mRNA, intracellular protein expression, and DNA binding activity of RelB were examined in immature and differentiated human DC, as well as other PB mononuclear cell populations. RelB protein and mRNA were detected constitutively in lymphocytes and in activated monocytes, differentiated DC, and monocyte-derived DC. Immunohistochemical staining demonstrated RelB within the differentiated lymph node interdigitating DC and follicular DC, but not undifferentiated DC in normal skin. Active nuclear RelB was detected by supershift assay only in differentiated DC derived from either PB precursors or monocytes and in activated B cells. These RelB(+) APC were potent stimulators of the MLR. The data indicate that RelB expression is regulated both transcriptionally and post-translationally in myeloid cells. Within the nucleus, RelB may specifically transactivate genes that are critical for APC function.

HYPOTHALAMIC COCAINE- AND AMPHETAMINE-REGULATED TRANSCRIPT AND CORTICOTROPHIN RELEASING FACTOR NEURONS ARE STIMULATED BY EXTRACELLULAR VOLUME AND OSMOTIC CHANGES

Several studies suggest that hypothalamic cocaine- and amphetamine-regulated transcript (CART) may interact with the hypothalamic-pituitary-adrenal (HPA) axis in the control of neuroendocrine function and may also participate in cardiovascular regulation. Therefore, this study aimed to evaluate, in experimental models of isotonic (I-EVE) and hypertonic (H-EVE) extracellular volume expansion and water deprivation (WD), the activation of CART- and corticotrophin releasing factor (CRF)-immunoreactive neurons, as well as the relative expression of CART and CRF mRNAs in the paraventricular (PVN) and supraoptic (SON) nuclei of the hypothalamus. Both H-EVE (0.30M NaCl, 2mL/100g of body weight, in 1 minute) and 24 hours of WD significantly increased plasma sodium concentrations, producing, respectively, either an increase or a decrease in extracellular volume. I-EVE (0.15M NaCl, 2mL/100g of body weight, in 1 minute) evoked a significant increase in the circulating volume accompanied by unaltered plasma concentrations of sodium. CART-expressing neurons of both magnocellular and parvocellular hypothalamic divisions were activated to produce Fos in response to H-EVE but not in response to I-EVE. Furthermore, increased expression of CART mRNA was found in the PVN of H-EVE but not I-EVE rats. These data show for the first time that EVE not only activates hypothalamic CRF neurons but also increases CRF mRNA expression in the PVN. In contrast, WD increases the number of CART-immunoreactive neurons activated to produce Fos in the PVN and SON but does not change the number of neurons double labeled for Fos and CRF or expression of CRF mRNA in the PVN. These findings provided new insights into the participation of CART in diverse processes within the PVN and SON, including its possible involvement in activation of the HPA axis and cardiovascular regulation in response to changes in extracellular volume and osmolality. (C) 2011 IBRO. Published by Elsevier Ltd. All rights reserved.

Ovarian function in Nelore (Bos taurus indicus) cows after post-ovulation hormonal treatments

Maternal recognition of pregnancy in the cow requires successful signaling by the conceptus to block luteolysis. Conceptus Growth and function depend on an optimal uterine environment, regulated by luteal progesterone. The objective of this study was to test strategies to optimize luteal function, as well as prevent a dominant follicle from initiating luteolysis. Nelore (Bos taurus indicus) beef cows (n = 40) were submitted to a GnRH/PGF(2 alpha)/GnRH protocol. Cows that ovulated from a dominant ovarian follicle (ovulation = Day 0) were allocated to receive: no additional treatment (Gc; n = 7); 3000 IU of hCG on Day 5 (G(hCG); n = 5); 5 mg of estradiol-17 beta on Day 12 (G(E2); n = 6); or 3000 IU of hCG on Day 5 and 5 mg of estradiol-17 beta on Day 12 (G(hCG/E2); n = 5). Ultrasonographic imaging of the ovaries, assessment of plasma progesterone concentration, and detection of estrus were done daily from Day 5 to the day of subsequent ovulation. Treatment with hCG induced an accessory CL, increased CL volume, and plasma progesterone concentration throughout the luteal phase (P < 0.01). Estradiol-17 beta induced atresia and recruitment of a new wave of follicular growth; it eliminated a potentially estrogen-active, growing ovarian follicle within the critical period for maternal recognition of pregnancy, but it also hastened luteolysis (Days 16 or 17 vs. Days 18 or 19 in non-treated cows). In conclusion, the approaches tested enhanced luteal function (hCG) and altered ovarian follicular dynamics (estradiol-17 beta), but were unable to extend the life-span of the CL in Nelore cows. (c) 2008 Elsevier Inc. All rights reserved.

Cdc25B activity is regulated by 14-3-3

In the G2 phase cell cycle checkpoint arrest, the cdc25-dependent activation of cyclin B/cdc2, a critical step in regulating entry into mitosis, is blocked. Studies in yeast have demonstrated that the inhibition of cdc25 function involves 14-3-3 binding to cdc25, In humans, two cdc25 isoforms have roles in G2/M progression, cdc25B and cdc25C, both bind 14-3-3, Abrogating 14-3-3 binding to cdc25C attenuates the G2 checkpoint arrest, but the contribution of 14-3-3 binding to the regulation of cdc25B function is unknown. Here we demonstrate that high level over-expression of cdc25B in G2 checkpoint arrested cells can activate cyclin B/cdc2 and overcome the checkpoint arrest. Mutation of the major 14-3-3 binding site, S323, or removal of the N-terminal regulatory domain are strong activating mutations, increasing the efficiency with which the mutant forms of cdc25B not only overcome the arrest, but also initiate aberrant mitosis, We also demonstrate that 14-3-3 binding to the S323 site on cdc25B blocks access of the substrate cyclin/cdks to the catalytic site of the enzyme, thereby directly inhibiting the activity of cdc25B, This provides direct mechanistic evidence that 14-3-3 binding to cdc25B can regulate its activity, thereby controlling progression into mitosis.

GPI-anchored proteins are delivered to recycling endosomes via a distinct cdc42-regulated, clathrin-independent pinocytic pathway

Endocytosis of cell-surface proteins via specific pathways is critical for their function. We show that multiple glycosylphosphatidylinositol-anchored proteins (GPI-APs) are endocytosed to the recycling endosomal compartment but not to the Golgi via a nonclathrin, noncaveolae mediated pathway. GPI anchoring is a positive signal for internalization into rab5-independent tubular-vesicular endosomes also responsible for a major fraction of fluid-phase uptake; molecules merely lacking cytoplasmic extensions are not included. Unlike the internalization of detergent-resistant membrane (DRM)-associated interleukin 2 receptor, endocytosis of DRM-associated GPI-APs is unaffected by inhibition of RhoA or dynamin 2 activity. Inhibition of Rho family GTPase cdc42, but not Rac1, reduces fluid-phase uptake and redistributes GPI-APs to the clathrin-mediated pathway. These results describe a distinct constitutive pinocytic pathway, specifically regulated by cdc42.

CD40 and dendritic cell function

CD40 has emerged as a key signaling pathway for the function of B cells, monocytes, and dendritic cells (DC) in the immune system, and plays a major role in inflammatory pathways of nonhemopoletic cells. CD40 is expressed by monocytes and DC and is up-regulated when DC migrate from the periphery to draining lymph nodes (DLN) in response to microbial challenge. CD154 signaling by MHC-restricted, activated CD4* T cells induces differentiation of DC, as defined by an increased surface expression of MHC, costimulatory, and adhesion molecules. Thus, CD40 functions in the adaptive immune response as a trigger for the expression of costimulatory molecules for efficient T-cell activation. CD40 ligation of DC also has the capacity to induce high levels of the cytokine IL-12, which polarizes CD4(+) T cells toward a T helper 1 (Th1) type, enhances proliferation of CD8(+) T cells, and activates NK cells. CD40 may also play an important role in the decision between tolerance and immunity and the generation of regulatory CD4(+) T cells that are thought to maintain peripheral self-tolerance in vivo.

Solving a signalized traffic intersection problem with an hyperbolic penalty function

Mathematical Program with Complementarity Constraints (MPCC) finds many applications in fields such as engineering design, economic equilibrium and mathematical programming theory itself. A queueing system model resulting from a single signalized intersection regulated by pre-timed control in traffic network is considered. The model is formulated as an MPCC problem. A MATLAB implementation based on an hyperbolic penalty function is used to solve this practical problem, computing the total average waiting time of the vehicles in all queues and the green split allocation. The problem was codified in AMPL.

A regulated response to mitochondrial dysfunction modulates longevity and rates of living

Aging is a long-standing biological question of tremendous social and cultural importance. Despite this, only in the last 15 years has biology started to make significant progress in understanding the underlying mechanisms that regulate aging. This progress stemmed mainly from the use of model organisms, which allowed the discovery of several genes directly modulating longevity. Interestingly, several of these longevity genes are necessary for normal mitochondrial function, and disruption of their activity delays the aging process. This is somewhat paradoxical, considering the importance of cellular respiration for energy production and viability of eukaryotic organisms. One possible rationalization for this is that by decreasing cellular respiration, reactive oxygen species (ROS) generation is also reduced, and in that way, cellular decay and aging are delayed.(...)

Dissecting the function of the SpoIIIJ and YqjG membrane protein insertases during bacterial spore development

Dissertation presented to obtain the Ph.D degree in Biology, Microbial Biology

Regulation and function of the cell wall polymer lipoteichoic acid in staphylococcus aureus

A thesis submitted for the Degree of Master in Medical microbiology

The role of IFNγ in higher brain function: in health and under chronic stress

Tese de Doutoramento em Ciências da Saúde

Study of the retinoic acid regulated genes in the rodent hypothalamus controlling growth and appetite and the potential for the epigenetic control

Dissertação de mestrado em Bioquímica (área de especialização em Biomedicina)

Public enterprise reforms and efficiency in regulated environments: the case of the postal sector

Purpose - This paper focuses on analyzing the effect that public reforms have on the efficiency of state-owned enterprises in regulated environments. Design/methodology/approach - The research is focused in the postal sector where public and private companies must obey a legal framework related to provide a universal service. The analysis is carried out using a panel of 7 European postal operators for the period 1997-2003. The activity analyzed was the letter mail division; we take as key variable the unit cost of a letter and use a translog cost function where as independent variables we include traffic levels, labor cost per employee, quality and availability of the service as well as the type of ownership (public or private). Additionally, in a second stage the geographical differences among countries are considered. Findings - Results indicate that postal operators that experienced organizational changes without being privatized, such as the Spanish and Greek operators, do not have higher unit costs than privatized postal operators like the one of Germany and the Netherlands. Moreover, we find that in all cases the operator of Ireland appear to be the most efficient. In this case restructuring process has been carried out giving an important leadership role to workers. This suggests us that labor culture could be a key variable to study when analyzing reform processes in public enterprises. Originality/value - Our findings show that in a regulated environment like in the postal sector, public and private companies can obtain similar efficiency levels in term of unit costs.