Transcriptional and post-transcriptional mechanisms of glucocorticoid antiproliferative effects

The medial prefrontal cortex: coordinator of autonomic, neuroendocrine and behavioural responses to stress

Responding to real or potential threats in the environment requires the coordination of autonomic, neuroendocrine and behavioural processes to promote adaptation and survival. These diverging systems necessitate input from the limbic forebrain to integrate and modulate functional output in accordance with contextual demand. In the present review, we discuss the potential role of the medial prefrontal cortex (mPFC) as a coordinator of behavioural and physiological stress responses across multiple temporal and contextual domains. Furthermore, we highlight converging evidence from rodent and human research indicating the necessity of the mPFC for modulating physiological energetic systems to mobilise or limit energetic resources as needed to ultimately promote behavioural adaptation in the face of stress. We review the literature indicating that glucocorticoids act as one of the primary messengers in the reallocation of energetic resources having profound effects locally within the mPFC, as well as shaping how the mPFC acts within a network of brain structures to modulate responses to stress. Finally, we discuss how both rodent and human studies point toward a critical role of the mPFC in the coordination of anticipatory responses to stress and why this distinction is an important one to make in stress neurobiology.

Short-term administration of steroids does not affect postoperative complications following liver resection: Evidence from a meta-analysis of randomized controlled trials

AIM

Although perioperative short-term administration of steroids can attenuate surgical stress response following liver resection, there is no consensus concerning the effect on postoperative complications. This study aims to use meta-analysis to quantitatively investigate the effect of perioperative short-term administration of steroids on postoperative complications following liver resection.

METHODS

A systematic published work search was performed to detect randomized controlled trials (RCT) assessing the effect of perioperative short-term administration of steroids on outcomes following liver resection. Parameters of surgical stress, hospital stay and postoperative complications were analyzed. Two authors independently assessed study quality and extracted data. All data were analyzed using RevMan version 5 and meta-analyses were performed using a random-effects model.

RESULTS

Five RCT published between 2001 and 2011 containing a total of 379 patients were eligible for final analysis. Serum total bilirubin, interleukin-6 and C-reactive protein were significantly lower in the steroid than in the control group on postoperative day 1 (P = 0.02, 0.004 and 0.02, respectively). There was no difference in duration of hospital stay between the steroid and control group (P = 0.37). The analysis of end-points including infective complications (odds ratio [OR], 0.95), wound complications (OR, 0.67), bile leakage (OR, 0.58) and overall complications (OR, 0.50) revealed no difference between steroid administration and no treatment. There was no postoperative death or adverse effect attributable to steroid treatment in all patients.

CONCLUSION

On currently available evidence, short-term administration of steroids does not increase incidence of complications in patients undergoing liver resection.

Physiological roles of glucocorticoids during early embryonic development of the zebrafish (Danio rerio)

While glucocorticoids (GCs) are known to be present in the zebrafish embryo, little is known about their physiological roles at this stage. We hypothesised that GCs play key roles in stress response, hatching and swim activity during early development. To test this, whole embryo cortisol (WEC) and corticosteroid-related genes were measured in embryos from 6 to 120 h post fertilisation (hpf) by enzyme linked immunosorbent assay (ELISA) and quantitative real-time polymerase chain reaction (qRT-PCR). Stress response was assessed by change in WEC following stirring, hypoxia or brief electrical impulses applied to the bathing water. The impact of pharmacological and molecular GC manipulation on the stress response, spontaneous hatching and swim activity at different stages of development was also assessed. WEC levels demonstrated a biphasic pattern during development with a decrease from 0 to 36 hpf followed by a progressive increase towards 120 hpf. This was accompanied by a significant and sustained increase in the expression of genes encoding cyp11b1 (GC biosynthesis), hsd11b2 (GC metabolism) and gr (GC receptor) from 48 to 120 hpf. Metyrapone (Met), an inhibitor of 11β-hydroxylase (encoded by cyp11b1), and cyp11b1 morpholino (Mo) knockdown significantly reduced basal and stress-induced WEC levels at 72 and 120 hpf but not at 24 hpf. Spontaneous hatching and swim activity were significantly affected by manipulation of GC action from approximately 48 hpf onwards. We have identified a number of key roles of GCs in zebrafish embryos contributing to adaptive physiological responses under adverse conditions. The ability to alter GC action in the zebrafish embryo also highlights its potential value for GC research.

Infradian modulation of circadian rhythms of proliferative activity of the esophageal and corneal epithelium

Many-day rhythms of proliferative activity of the corneal and esophageal epithelium and serum corticosterone levels were studied in adult male Wistar rats. We detected a 4-day rhythm of proliferative activity of esophageal epithelium negatively correlating with corticosterone level. A more pronounced decrease in the number of mitoses in the esophageal and corneal epithelium was recorded every 12 days. Analysis of the rhythm of mitotic activity in different experimental series carried out over 9 months showed that the acrophase of the detected 4- and 12-day periods is shifted 1 day forward every 69-73 days. The detected infradian constituents of the circadian rhythms of epithelial proliferative activity should be taken into consideration in experimental studies and in development of chronobiological approaches to the treatment of diseases caused by disorders of the proliferative activity of the epithelium.

11β-Hydroxysteroid Dehydrogenase Type II is a Potential Target for Prevention of Colorectal Tumorigenesis

Colorectal cancer (CRC) is a leading cause of cancer death, yet primary prevention remains the best approach to reducing overall morbidity and mortality. There is a clear molecular link between cyclooxygenase-2 (COX-2)-derived prostaglandin E₂ (PGE₂) production and CRC progression. Although selective COX-2 inhibitors as well as non-steroidal anti-inflammatory drugs (NSAIDs) reduce the number and sizes of colonic adenomas, increased cardiovascular risks of selective COX-2 inhibitors and increased gastrointestinal side-effects of NSAIDs limit their use in chemoprevention of CRC. Glucocorticoids induce apoptosis and are endogenous, potent COX-2 inhibitors. Glucocorticoids have been used for the treatment of hematologic malignancies, but not for solid tumors due to adverse side-effects such as immunosuppression and osteoporosis. In tissues, glucocorticoid actions are down-regulated by t y p e 2 1 1 β-hydroxysteroid dehydrogenase (11βHSD2), and inhibition of 11βHSD2 activity will elevate intracellular active glucocorticoid to levels that effectively suppress COX-2 expression. Both COX-2 and 11βHSD2 increase in Apc^+/min mouse intestinal adenomas and human colonic adenomas and either pharmacologic or genetic 11βHSD2 inhibition leads to decreases in COX-2-mediated PGE₂ production in tumors and prevents adenoma formation, tumor growth, and metastasis. 11βHSD2 inhibition may represent a novel approach for CRC chemoprevention by increasing tumor cell intracellular glucocorticoid activity, which in turn inhibits tumor growth by suppressing the COX-2-derived PGE₂ pathway, as well as other pathways, without potential side-effects relating to chronic application of COX-2 inhibitors, NSAIDs and glucocorticoids.

Several-day rhythmic changes in lymphocyte subpopulation composition and peripheral blood levels of interleukin-2 and hydrocortisone in donors

Several-day rhythmic changes in the lymphocyte subpopulation composition and peripheral blood levels of IL-2 and hydrocortisone were studied in healthy men. The samples were collected daily at 8.00. A 4-day rhythm of hydrocortisone secretion manifested synchronously in different individuals. Rhythmic changes in IL-2 level, T-helper/T-suppressor cytotoxic lymphocyte index, and percentage of NK cells in the peripheral blood related to the hormone levels were detected. Rhythmic changes in these parameters should be taken into consideration when evaluating the hormonal profiles and immunological status of healthy subjects and development of methods for correction of abnormalities.

Monocyte and T-cell responses to exercise training in elderly subjects

The purpose of this study was to examine the effects of exercise training on age-related impairment of immune parameters related to T-cell activation in elderly individuals. Twenty-four elderly subjects were assigned to an exercise training group (EXC: 3 men, 9 women; age 61-76 years) or a nonexercise control group (CON: 4 men, 8 women; age 62-79 years). Subjects in EXC participated in exercise sessions 2 d·wk(-1) for 12 weeks. The training session included stretching and endurance exercise (10 minutes), resistance training comprised leg extension, leg press, hip abduction, and hip adduction using exercise machine and each subject's body weight. Subjects in CON maintained their normal physical activity levels during the study period. Blood samples were collected before and after the training period. Samples were measured for the numbers of leukocytes, lymphocytes, and monocytes, and for CD3(+), CD4(+), CD8(+), CD28(+)CD4(+), CD28(+)CD8(+), TRL-4(+)CD14(+), and CD80(+)CD14(+) cells. The number of leukocytes, lymphocytes, monocytes, CD3(+), CD4(+), and CD8(+) cells did not change after 12 weeks in either EXC or CON. The number of CD28(+)CD8(+) cells increased significantly after training in EXC (p ≤ 0.05), although CON showed no significant change. In the EXC group, CD80(+)CD14(+) cell counts were significantly higher after training (p ≤ 0.05), but the TLR-4(+)CD14(+) cell counts were unchanged. In the CON group, no significant alteration existed in TLR-4(+)CD14(+) and CD80(+)CD14(+) cell numbers. In conclusion, exercise training in elderly people is associated with increased CD28-expressing Tc cells and CD80-expressing monocytes. Therefore, exercise training might upregulate monocyte and T-cell-mediated immunity in elderly people.

Fish metalloproteins as biomarkers of environmental contamination

Fish are well-recognized bioindicators of environmental contamination. Several recent proteomic studies have demonstrated the validity and value of using fish in the search and discovery of new biomarkers. Certain analytical tools, such as comparative protein expression analyses, both in field and lab exposure studies, have been used to improve the understanding of the potential for chemical pollutants to cause harmful effects. The metallomic approach is in its early stages of development, but has already shown great potential for use in ecological and environmental monitoring contexts. Besides discovering new metalloproteins that may be used as biomarkers for environmental contamination, metallomics can be used to more comprehensively elucidate existing biomarkers, which may enhance their effectiveness. Unfortunately, metallomic profiling for fish has not been explored, because only a few fish metalloproteins have thus far been discovered and studied. Of those that have, some have shown ecological importance, and are now successfully used as biomarkers of environmental contamination. These biomarkers have been shown to respond to several types of environmental contamination, such as cyanotoxins, metals, and sewage effluents, although many do not yet possess any known function. Examples of successes include MMPs, superoxide dismutases, selenoproteins, and iron-bound proteins. Unfortunately, none of these have, as yet, been extensively studied. As data are developed for them, valuable new information on their roles in fish physiology and in inducing environmental effects should become available.

Prednisolone phosphate-containing TRX-20 liposomes inhibit cytokine and chemokine production in human fibroblast-like synovial cells: a novel approach to rheumatoid arthritis therapy

To evaluate the potential of using prednisolone phosphate (PSLP)-containing 3,5-dipentadecyloxybenzamidine hydrochloride (TRX-20) liposomes to treat rheumatoid arthritis (RA), we examined their ability to bind human fibroblast-like synovial (HFLS) cells and their effects in these cells. To test for binding, Lissamine rhodamine B-1, 2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine (rhodamine)-labelled PSLP-containing TRX-20 liposomes were added to HFLS cells, and the fluorescence intensity of the rhodamine bound to the cells was evaluated. Rhodamine-labelled PSLP-containing liposomes without TRX-20 were used as a negative control. To evaluate the uptake of liposomes by the HFLS cells, we used TRX-20 liposomes containing 8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS) and p-xylene-bis-pyridinium bromide (DPX), and observed the cells by fluorescence microscopy. The effects of the PSLP in TRX-20 liposomes on HFLS cells were assessed by the inhibition of the production of two inflammatory cytokines (interleukin 6 and granulocyte macrophage colony-stimulating factor) and one inflammatory chemokine (interleukin 8). The interaction of the PSLP-containing TRX-20 liposomes with HFLS cells was approximately 40 times greater than that of PSLP-containing liposomes without TRX-20. PSLP-containing TRX-20 liposomes bound to HFLS cells primarily via chondroitin sulfate. TRX-20 liposomes taken up by the cell were localized to acidic compartments. Furthermore, the PSLP-containing TRX-20 liposomes inhibited the production of the inflammatory cytokines and the chemokine more effectively than did the PSLP-containing liposomes without TRX-20. These results indicate that PSLP-containing TRX-20 liposomes show promise as a novel drug delivery system that could enhance the clinical use of glucocorticoids for treating RA.

Glucocorticoid-induced leucine zipper (GILZ): a new important mediator of glucocorticoid action

Glucocorticoids (GCs) represent the mainstay of current anti-inflammatory and immunosuppressive strategies, mediating effects that mostly result in transcriptional regulation of glucocorticoid receptor target genes. A variety of actions are tied together in the response to GC treatment. Dissecting the beneficial from the detrimental actions in GC therapy is a major challenge in basic research, raising the critical issue of whether a single target gene or gene family might eventually be linked to a specific GC function. Glucocorticoid-induced leucine zipper (GILZ) was originally discovered in studies aimed at characterizing genes targeted by dexamethasone. The first suggestion that GILZ plays an important role in GC immunomodulation came from observations of GILZ up-regulation by GCs, mainly in lymphoid organs, and inhibition of anti-CD3-induced activation and apoptosis. The identification of GILZ interaction with and inhibition of NF-kappaB provided a first molecular mechanistic basis for explaining GILZ effects on T cells. Subsequently, other GILZ targets have been identified, including AP-1, Raf-1, and Ras, all involved in GC effects. The finding that GILZ silencing abrogates the antiproliferative activity of dexamethasone and reduces GC inhibition of cytokine-induced COX-2 expression clearly gained GILZ a distinguished reputation within the critical mediators of GC effects. The multiple functions of GILZ and their potential biological relevance are here reviewed.

Distinctly different expression of cytokines and chemokines in the lungs of two H5N1 avian influenza patients

The pathogenesis of human H5N1 influenza remains poorly understood and controversial. 'Cytokine storm' has been hypothesized to be the main cause of the severity of this disease. However, the significance of this hypothesis has been called into question by a recent report, which demonstrates that inhibition of the cytokine response did not protect against lethal H5N1 influenza infection in mice. Here we showed discrepant findings in two adult H5N1 autopsies and a fetus obtained at autopsy which also raise doubt about this hypothesis. Antigens of 10 cytokines/chemokines which were found to be significantly elevated in previous H5N1-infected patients and in vitro experiments, and mRNA of eight of these, were absent from the lungs of a pregnant woman and her fetus. In contrast, antigens of seven cytokines/chemokines and mRNA of six of these were found to be increased in the lungs of a male autopsy. The cells expressing these cytokines and chemokines were identified as type II pneumocytes, bronchial epithelial cells, macrophages and vascular endothelial cells. Levels of cytokines and chemokines in the serum of the male case were also significantly higher than those of infectious (infection other than by H5N1) and non-infectious controls. In comparison with results from our previous study, it appeared that the male case had increased cytokine/chemokine expression but reduced viral load, while the pregnant female had diminished cytokine/chemokine expression but a significantly increased viral load in the lungs. These disparate findings in these two cases suggest that 'cytokine storm' alone could not be a sufficient explanation for the severe lung injury of this newly emerging disease.

Elevated maternal corticosterone during lactation hinders the neonatal adaptive immune response to herpes simplex virus (HSV) infection

The neonate's immune system is relatively immature. For short-term protection against pathogens the neonate is reliant primarily on maternally derived antibodies delivered via the mother's milk. However, neonates soon acquire the ability to generate adaptive immune responses for long-term protection. Products of the nervous and endocrine systems that are elicited by psychological stress are known to modulate a variety of immune responses. Additionally, psychological stressors are well recognized for their ability to increase corticosterone levels. The studies described herein examined the effects of increases in maternally derived corticosterone on the neonatal cell-mediated immune response to, and pathogenicity of, herpes simplex virus (HSV) infection. Water containing corticosterone was made available to nursing mothers for a period of 6 consecutive days beginning on either the day of or 6 days post-delivery. At 12 days of age, neonates were infected with HSV-1 in the rear footpads. These neonates exhibited a decrease in the proliferative ability of splenic-derived cells due to the reduction of IL-2 production and IL-2 receptor alpha subunit (IL-2R alpha) expression by these cells. These neonates also exhibited a decrease in the number and function of popliteal lymph node-resident HSV-1 gB(498-505) peptide-specific CD8(+) T cells as measured by tetramer analysis, CTL lytic activity, expression of CD107a, cytokine production, and proliferation. Additionally, these HSV-infected neonates exhibited increased morbidity and mortality. Together, these studies indicate that exposure of neonates to maternally derived corticosterone via the milk hinders their ability to generate an adaptive cell-mediated immune response to a viral infection and illustrate the potential importance of maternal stress in neonatal resistance to infectious pathogens.

Glucocorticoids alter craniofacial development and increase expression and activity of matrix metalloproteinases in developing zebrafish (Danio rerio)

Teratogenic effects are observed following long-term administration of glucocorticoids, although short-term glucocorticoid therapy is still utilized to reduce fetal mortality, respiratory distress syndrome, and intraventricular hemorrhage in preterm infants. However, the mechanism of glucocorticoid-induced teratogenicity is unknown. We hypothesize that glucocorticoid-induced teratogenesis is mediated through the glucocorticoid receptor (GR) and results from altering the expression and activity of the matrix metalloproteinases (MMPs). During embryogenesis, degradation of the extracellular matrix to allow for proper cellular migration and tissue organization is a tightly regulated process requiring appropriate temporal and spatial expression and activity of the MMPs. Studies have demonstrated that MMP gene expression can be either inhibited or induced by glucocorticoids in a variety of model systems. Using the zebrafish (Danio rerio) as a model of development, the data presented here demonstrate that embryonic exposure to the glucocorticoids dexamethasone or hydrocortisone increased expression of two gelatinases, MMP-2 ( approximately 1.5-fold) and MMP-9 (7.6- to 9.0-fold), at 72 h postfertilization (hpf). Further, gelatinase activity was increased approximately threefold at 72 hpf following glucocorticoid treatment, and changes in craniofacial morphogenesis were also observed. Cotreatment of zebrafish embryos with each glucocorticoid and the GR antagonist RU486 resulted in attenuation of glucocorticoid-induced increases in MMP expression (52-84% decrease) and activity (41-94% decrease). Furthermore, the abnormal craniofacial phenotype observed following glucocorticoid exposure was less severe following RU486 cotreatment. These studies demonstrate that in the embryonic zebrafish, dexamethasone, and hydrocortisone alter expression and activity of MMP-2 and -9, and suggest that these increases may be mediated through the GR.

Trichostatin A, sodium butyrate, and 5-aza-2′-deoxycytidine alter the expression of glucocorticoid receptor α and β isoforms in Hut-78 T- and Raji B-lymphoma cell lines

The glucocorticoid receptor (GR) is mainly expressed as nine-exon alternatively spliced variants, encoding functional GRalpha and nonfunctional GRbeta. Overexpression of GRbeta splice variant was found in glucocorticoid-resistant patients with some autoimmune diseases and hematological malignancies. Employing reverse transcription, real-time quantitative PCR, and western blot analysis, we determined an effect of trichostatin A (TSA), sodium butyrate (NaBu) and 5-aza-2'-deoxycytidine (5-dAzaC) on GRalpha and GRbeta expression in Hut-78 T- and Raji B-lymphoma cell lines. We found that TSA, NaBu, and 5-dAzaC significantly increase the expression of GRalpha transcript and protein, whereas GRbeta transcript and protein expression was profoundly decreased in Hut-78 T- and Raji B- lymphoma cell lines. Our observation suggests that changes of epigenetic milieu inside cells may alter the expression of GRalpha and GRbeta isoforms.

GILZ mediates the antiproliferative activity of glucocorticoids by negative regulation of Ras signaling

Tsc22d3 coding for glucocorticoid-induced leucine zipper (GILZ) was initially identified as a dexamethasone-responsive gene involved in the control of T lymphocyte activation and apoptosis. However, the physiological role of this molecule and its function in the biological activity of glucocorticoids (GCs) has not been clarified. Here, we demonstrate that GILZ interacts directly with Ras in vitro and in vivo as shown by GILZ and Ras coimmunoprecipitation and colocalization upon PMA activation in primary mouse spleen T lymphocytes and thymus cells. The analysis of GILZ mutants showed that they bound Ras through the tuberous sclerosis complex box (TSC) and, depending on the Ras activation level, formed a trimeric complex with Ras and Raf, which we previously identified as a GILZ binder. As a consequence of these interactions, GILZ diminished the activation of Ras and Raf downstream targets including ERK1/2, AKT/PKB serine/threonine kinase, and retinoblastoma (Rb) phosphorylation and cyclin D1 expression, leading to inhibition of Ras- and Raf-dependent cell proliferation and Ras-induced NIH-3T3 transformation. GILZ silencing resulted in an increase in concanavalin A-induced T cell proliferation and, most notably, inhibition of dexamethasone antiproliferative effects. Together, these findings indicate that GILZ serves as a negative regulator of Ras- and Raf-induced proliferation and is an important mediator of the antiproliferative effect of GCs.

Pharmacotherapeutic Uses of Hormones

This article reviews the use of hormones and related molecules in pharmacology. Examples of hormones in the treatment of specific diseases is presented, including those where normal physiologic levels of hormones are restored, and others where supraphysiologic levels are used to achieve a therapeutic effect. Examples of the abuse of hormones are also described.

Glucocorticoid up-regulates transforming growth factor-beta (TGF-beta) type II receptor and enhances TGF-beta signaling in human prostate cancer PC-3 cells

Previous studies have shown that dexamethasone (Dex) induces the expression of TGF-beta1 in androgen-independent prostate cancer both in vitro and in vivo. However, it is not clear whether Dex has a direct effect on the expression of TGF-beta receptors. In this study, using the androgen-independent human prostate cancer cell line, PC-3 cells, we demonstrated that Dex increased the expression of TGF-beta receptor type II (TbetaRII), but not TGF-beta receptor type I (TbetaRI) in a time- and dose-dependent manner. The up-regulation of TbetaRII expression by Dex was mediated by glucocorticoid receptor and occurred at the transcriptional level. Dex also enhanced TGF-beta1 signaling and increased the expression of cyclin-dependent kinase inhibitors p15(INK4B) (p15) and p27(KIP1) (p27), which are the target genes of TGF-beta1 and have been identified as inducers of cell cycle arrest at the G1 checkpoint. The antiproliferative effect of Dex was partially blocked by anti-TbetaRII antibody, indicating that elevated TbetaRII and TGF-beta1 signaling were involved in the antiproliferative effect of Dex. Because the TGF-beta1 pathway could not fully explain the antiproliferative effect of Dex, we further examined the effects of Dex on the transcriptional activity of nuclear factor-kappaB (NF-kappaB) and the expression of IL-6 and found that Dex suppressed the transcriptional activity of NF-kappaB and IL-6 mRNA expression in PC-3 cells. These results demonstrated that glucocorticoid inhibited the proliferation of PC-3 cells not only through enhancing growth-inhibitory TGF-beta1 signaling, but also through suppressing transcriptional activities of NF-kappaB.

Glucocorticoid receptors modulate auditory sensitivity to acoustic trauma

Glucocorticoids are widely used to treat different hearing disorders yet the exact mechanisms of glucocorticoid action on the inner ear are not known. The inner ear of both humans and experimental animals demonstrate an abundance of glucocorticoid receptors (GRs) in both neuronal and non-neuronal tissues. In this review, we discuss how activation of the hypothalamic-pituitary-adrenal axis can directly modulate hearing sensitivity. Recent findings indicate that several factors define the responsiveness of the peripheral auditory system to glucocorticoids including the concentration of agonist, availability of the GR, and the activation of GR and NF-kappaB. These findings will further our understanding of individual glucocorticoid responsiveness to steroid treatment, and will help improve the development of pharmaceuticals to selectively target GR in the inner ear for individuals with increased sensitivity to acoustic trauma.

The Physiology of Human Glucocorticoid Receptor beta (hGRbeta) and Glucocorticoid Resistance

The development of glucocorticoid (GC) resistance is a serious problem that complicates the treatment of immune-related diseases, such as asthma, ulcerative colitis, and hematologic cancers. hGRalpha and hGRbeta are two isoforms of the human glucocorticoid receptor, which differ in the structural composition of the carboxy-terminal end of the ligand-binding domain and therefore in their ability to bind glucocorticoid ligand and in their physiological function. hGRalpha is the classically functional GR, while hGRbeta seems to act mainly as a dominant negative to the function of hGRalpha. Because of the ability of hGRbeta to antagonize the action of hGRalpha, it has been hypothesized that changes in the expression of hGRbeta may underlie the development of glucocorticoid resistance. In this article we review what is known about the expression and physiological action of hGRbeta in normal cells and tissue as well as in several disease states. Taken together, the evidence suggests that the ratio of hGRalpha:hGRbeta expression is indeed critical to the glucocorticoid responsiveness of various cells. This ratio can be altered by changing the expression level of hGRalpha, hGRbeta, or both receptors simultaneously. Higher ratios correlate with glucocorticoid sensitivity, while lower ratios correlate with glucocorticoid resistance. Thus hGRbeta can be an important modulator of glucocorticoid responsiveness.

Activation of the hypothalamic-pituitary-adrenal axis and autonomic nervous system during inflammation and altered programming of the neuroendocrine-immune axis during fetal and neonatal development: lessons learned from the model inflammagen, lipopolysaccharide

The hypothalamic-pituitary-adrenal axis (HPAA) and autonomic nervous system (ANS) are both activated during inflammation as an elaborate multi-directional communication pathway designed to restore homeostasis, in part, by regulating the inflammatory and subsequent immune response. During fetal and neonatal development programming of the HPAA, ANS and possibly the immune system is influenced by signals from the surrounding environment, as part of an adaptive mechanism to enhance the survival of the offspring. It is currently hypothesized that if this programming is either misguided, or the individual's environment is drastically altered such that neuroendocrine programming becomes maladaptive, it may contribute to the pathogenesis of certain diseases. Current research, suggests that exposure to inflammatory signals during critical windows of early life development may influence the programming of various genes within the neuroendocrine-immune axis. This review will provide, (1) an overview of the HPAA and ANS pathways that are activated during inflammation, highlighting studies that have used lipopolysaccharide as a model inflammagen and, (2) evidence to support the hypothesis that inflammatory stress during fetal and neonatal development can alter programming of the neuroendocrine-immune axis, influencing stress and immune responsiveness, and possibly disease resistance later in life.

Camurati-Engelmann disease: review of the clinical, radiological, and molecular data of 24 families and implications for diagnosis and treatment

Camurati-Engelmann disease (CED) is a rare autosomal dominant type of bone dysplasia. This review is based on the unpublished and detailed clinical, radiological, and molecular findings in 14 CED families, comprising 41 patients, combined with data from 10 other previously reported CED families. For all 100 cases, molecular evidence for CED was available, as a mutation was detected in TGFB1, the gene encoding transforming growth factor (TGF) beta1. Pain in the extremities was the most common clinical symptom, present in 68% of the patients. A waddling gait (48%), easy fatigability (44%), and muscle weakness (39%) were other important features. Radiological symptoms were not fully penetrant, with 94% of the patients showing the typical long bone involvement. A large percentage of the patients also showed involvement of the skull (54%) and pelvis (63%). The review provides an overview of possible treatments, diagnostic guidelines, and considerations for prenatal testing. The detailed description of such a large set of CED patients will be of value in establishing the correct diagnosis, genetic counselling, and treatment.

Comparison of Helicobacter spp. in Cheetahs (Acinonyx jubatus) with and without gastritis

Chronic gastritis causes significant morbidity and mortality in captive cheetahs but is rare in wild cheetahs despite colonization by abundant spiral bacteria. This research aimed to identify the Helicobacter species that were associated with gastritis in captive cheetahs but are apparently commensal in wild cheetahs. Helicobacter species were characterized by PCR amplification and sequencing of the 16S rRNA, urease, and cagA genes and by transmission electron microscopy of frozen or formalin-fixed paraffin-embedded gastric samples from 33 cheetahs infected with Helicobacter organisms (10 wild without gastritis and 23 captive with gastritis). Samples were screened for mixed infections by denaturant gel gradient electrophoresis of the 16S rRNA gene and by transmission electron microscopy. There was no association between Helicobacter infection and the presence or severity of gastritis. Eight cheetahs had 16S rRNA sequences that were most similar (98 to 99%) to H. pylori. Twenty-five cheetahs had sequences that were most similar (97 to 99%) to "H. heilmannii" or H. felis. No cheetahs had mixed infections. The ultrastructural morphology of all bacteria was most consistent with "H. heilmannii," even when 16S rRNA sequences were H. pylori-like. The urease gene from H. pylori-like bacteria could not be amplified with primers for either "H. heilmannii" or H. pylori urease, suggesting that this bacteria is neither H. pylori nor "H. heilmannii." The cagA gene was not identified in any case. These findings question a direct role for Helicobacter infection in the pathogenesis of gastritis and support the premise that host factors account for the differences in disease between captive and wild cheetah populations.

The physiological regulation of toll-like receptor expression and function in humans

Eleven mammalian toll-like receptors (TLRs 1-11) have been identified to date and are known to play a crucial role in the regulation of immune responses; however, the factors that regulate TLR expression and function in vivo are poorly understood. Therefore, in the present study, we investigated the physiological regulation of TLR expression and function in humans. To examine the influence of diurnal rhythmicity on TLR expression and function, peripheral venous blood samples were collected from healthy volunteers (n = 8) at time points coinciding with the peak and nadir in the endogenous circulating cortisol concentration. While no diurnal rhythmicity in the expression of TLRs 1, 2, 4 or 9 was observed, the upregulation of costimulatory (CD80 and CD86) and antigen-presenting (MHC class II) molecules on CD14(+) monocytes following activation with specific TLR ligands was greater (P < 0.05) in samples obtained in the evening compared with the morning. To examine the influence of physical stress on TLR expression and function, peripheral venous blood samples were collected from healthy volunteers (n = 11) at rest and following 1.5 h of strenuous exercise in the heat (34 degrees C). Strenuous exercise resulted in a decrease (P < 0.005) in the expression of TLRs 1, 2 and 4 on CD14(+) monocytes. Furthermore, the upregulation of CD80, CD86, MHC class II and interleukin-6 by CD14(+) monocytes following activation with specific TLR ligands was decreased (P < 0.05) in samples obtained following exercise compared with at rest. These results demonstrate that TLR function is subject to modulation under physiological conditions in vivo and provide evidence for the role of immunomodulatory hormones in the regulation of TLR function.

Steroid administration before partial hepatectomy with temporary inflow occlusion does not influence cyclin D1 and Ki-67 related liver regeneration

BACKGROUND AND AIMS

If temporary inflow occlusion is required during liver resection, the postoperative course might be complicated by ischaemia-reperfusion injury. Steroids protect against ischaemia-reperfusion injury; however, due to its anti-proliferative character concerns exist on its use on liver regeneration after resection. We investigated the effects of methylprednisolone on hepatocyte proliferation after partial hepatectomy with temporary inflow occlusion.

PATIENTS AND METHODS

Prior to surgery, one group of Wistar rats received methylprednisolone, while a second group served as non-treated controls. Ischaemia-reperfusion injury was indicated by AST, ALT, and GLDH at 6 h after surgery. Immunohistochemistry tools were used to determine the mitotic index and Ki-67 expression, while cyclin D1 expression characterized the proliferative activity on days 1, 4, 7, and 10.

RESULTS

The post-ischaemic liver enzyme release had significantly decreased in the methylprednisolone group, while expression of cyclin D1, percentage of Ki-67-positive cells, and mitotic cell index were comparable in both groups. Similar results were found for bilirubin and albumin and for weight of proliferating liver.

CONCLUSION

Although steroid administration significantly reduced ischaemia-reperfusion-associated tissue injury, it has no apparent effects on hepatic regeneration. Thus, steroids could be recommended if a temporary liver ischaemia is required during surgery, in order to reduce complications caused by severe ischaemia-related organ dysfunction.

[Topical corticosteroids]

Therapeutics in dermatology underwent complete change after the introduction of topical hydrocortisone in the Fifties. At the time, stronger derivatives than hydrocortisone were synthetised and the indications for topical corticosteroids were expanded. Around twenty different molecules, classified according to their strength, are currently available for prescription in France. Many inflammatory or tumoral skin diseases respond to these products. The choice of a topical corticosteroid (strength, vehicle.) and of its mode of application (technique, rhythm of application) is oriented by the context (dermatitis treated, localization) and must respect "Good clinical practice" guidelines so as to select the best benefit/risk ratio.

On the link between Bcl-2 family proteins and glucocorticoid-induced apoptosis

As immunosuppressive agents, glucocorticoids (GCs) act by inhibiting the expression of cytokines and adhesion molecules at the transcriptional and post-transcriptional levels. In addition, GCs exerted their effects by modulating apoptosis. In view of the central role of the Bcl-2 family protein in regulating apoptosis, it was tempting to speculate that GCs modulated apoptosis through modulation of the expression of proapoptotic (Bax, Bcl-X(S), Bak) and prosurvival (Bcl-2, Bcl-X(L), Bcl-w) Bcl-2 family members. Prosurvival Bcl-2 family members in various cell types antagonized GC-induced apoptosis, thereby suggesting a causal relationship between GC-induced apoptosis and Bcl-2 proteins. The antagonism of apoptosis afforded by prosurvival Bcl-2 proteins appeared to be specific for the GCs, as Bcl-2 and Bcl-x(L) blocked GC-induced apoptosis in T cell hybridomas but did not affect Fas or activation-induced apoptosis. Although it is speculated that GC-induced apoptosis may be mediated through the activation of proapoptotic Bcl-2 proteins, recent findings suggest that this may vary depending on the conditions and the cell types used. The mechanism by which Bcl-2 inhibited GC-induced apoptosis remains uncertain. It was suggested that Bcl-2 acted on outer mitochondrial membranes to preserve their function. Bcl-2 overexpression also inhibited GC-induced apoptotic events, including caspase activation and mitochondrial dysfunction. The cross-talk of the GC receptors with other secondary messengers could lead to modulation of the activity of Bcl-2 proteins through modification of their phosphorylation status, without ruling out the possibility of a physical interaction between activated GR with Bcl-2 proteins.

Acquired resistance of human T cells to sulfasalazine: stability of the resistant phenotype and sensitivity to non-related DMARDs

BACKGROUND

A recent study from our laboratory showed that induction of the multidrug resistance related drug efflux pump ABCG2 contributed to acquired resistance of human T cells to the disease modifying antirheumatic drug (DMARD) sulfasalazine (SSZ).

OBJECTIVES

To investigate the duration of SSZ resistance and ABCG2 expression after withdrawal of SSZ and rechallenging with SSZ, and to assess the impact of SSZ resistance on responsiveness to other DMARDs.

METHODS

Human CEM cells (T cell origin) with acquired resistance to SSZ (CEM/SSZ) were characterised for (a) SSZ sensitivity and ABCG2 expression during withdrawal and rechallenge of SSZ, and (b) antiproliferative efficacy of other DMARDs.

RESULTS

ABCG2 protein expression was stable for at least 4 weeks when CEM/SSZ cells were grown in the absence of SSZ, but gradually declined, along with SSZ resistance levels, to non-detectable levels after withdrawal of SSZ for 6 months. Rechallenging with SSZ led to a rapid (<2.5 weeks) resumption of SSZ resistance and ABCG2 expression as in the original CEM/SSZ cells. CEM/SSZ cells displayed diminished sensitivity to the DMARDs leflunomide (5.1-fold) and methotrexate (1.8-fold), were moderately more sensitive (1.6-2.0 fold) to cyclosporin A and chloroquine, and markedly more sensitive (13-fold) to the glucocorticoid dexamethasone as compared with parental CEM cells.

CONCLUSION

The drug efflux pump ABCG2 has a major role in conferring resistance to SSZ. The collateral sensitivity of SSZ resistant cells for some other (non-related) DMARDs may provide a further rationale for sequential mono- or combination therapies with distinct DMARDs upon decreased efficacy of SSZ.

The interplay between the glucocorticoid receptor and nuclear factor-kappaB or activator protein-1: molecular mechanisms for gene repression

The inflammatory response is a highly regulated physiological process that is critically important for homeostasis. A precise physiological control of inflammation allows a timely reaction to invading pathogens or to other insults without causing overreaction liable to damage the host. The cellular signaling pathways identified as important regulators of inflammation are the signal transduction cascades mediated by the nuclear factor-kappaB and the activator protein-1, which can both be modulated by glucocorticoids. Their use in the clinic includes treatment of rheumatoid arthritis, asthma, allograft rejection, and allergic skin diseases. Although glucocorticoids have been widely used since the late 1940s, the molecular mechanisms responsible for their antiinflammatory activity are still under investigation. The various molecular pathways proposed so far are discussed in more detail.

Human SP-A 3'-UTR variants mediate differential gene expression in basal levels and in response to dexamethasone

Human surfactant protein A (SP-A) is encoded by two genes (SP-A1, SP-A2), and each is identified with several alleles. SP-A is involved in normal lung function, innate immunity, inflammatory processes, and is regulated by glucocorticoids. We investigated the role of 3'-untranslated region (UTR) of 10 SP-A variants on gene expression using transient transfection of 3'-UTR constructs in the human lung adenocarcinoma cell line NCI-H441. We found: 1) both basal mRNA and protein levels of the reporter gene of SP-A 3'-UTR constructs are significantly (P < 0.01) reduced compared with controls (vector pGL3 and surfactant protein B pGL3) and that differences exist among alleles; and 2) after dexamethasone (Dex) treatment (100 nM for 16 h), mRNA was reduced (31-51%). Seven alleles showed a significant decrease (P < 0.05) in mRNA, and three did not. Reporter activity was also decreased, from 17% (1A(1)) to 38% (1A), with six alleles showing a significant decrease. The data indicate that the 3'-UTR of SP-As play a differential role in SP-A basal expression and in response to Dex. Therefore, a careful consideration of individual use of steroid treatment may be considered.

IL-20: a new target for the treatment of inflammatory skin disease

The discovery of dramatic pro-inflammatory effects of IL-20 on skin highlighted a novel regulatory pathway in cutaneous inflammation. Specific receptor complexes for IL-20 are induced on keratinocytes and transmit potent signals via the signal transducer and activator of transcription-3. In response to IL-20, keratinocytes proliferate and express pro-inflammatory genes including TNF-alpha, which leads to activation of NF-kappaB. Recently, two related cytokines, IL-19 and IL-24, have been shown to trigger the IL-20 receptor, and a second receptor complex has also been found to respond to IL-20 and IL-24. IL-20 signalling appears to be a prominent component of cutaneous inflammation, but the extent to which inflammatory processes rely upon it is unknown. Nonetheless, the prevalence of diseases involving pathological cutaneous inflammation makes the identification of safe and effective anti-inflammatory therapies for the skin a priority. Detailed understanding of the signal transduction pathways by which the skin responds to IL-20 and related factors may make it possible to develop new pharmaceutical agents to selectively suppress cutaneous inflammation.

Enzymology and Molecular Biology of Glucocorticoid Metabolism in Humans

Glucocorticoids (GCs) are a vital class of steroid hormones that are secreted by the adrenal cortex and that are regulated by ACTH largely under the control of the hypothalamic-pituitary-adrenal axis. GCs mediate profound and diverse physiological effects in vertebrates, ranging from development, metabolism, neurobiology, anti-inflammation and programmed cell death to many other fuctions. Multiple factors "downstream" of GC secretion, such as glucocorticoid receptor (GR) number and the abundance of plasma binding proteins have originally been considered as modulators of GC action. However, in the last decade the role of tissue-specific GC activating and inactivating enzymes have been identified as additional determinants in GC signalling pathways. On the cellular level, they function as important pre-receptor regulators by acting as "molecular switches" for receptor-active and receptor-inactive GC hormones. According to their biologic activity to catalyze the interconversion of C11-hydroxyl and C11-oxo GCs these enzymes have been named 11beta-hydroxysteroid dehydrogenase (11beta-HSD; EC 1.1.1.146). Two isoforms of 11beta-HSD have been cloned and characterized so far. 11beta-HSD type 1 is found in a wide range of tissues, acts predominantly as a reductase in intact cells and tissues by regenerating active cortisol from cortisone, and has been described to regulate GC access to the GR. 11beta-HSD type 2 is found mainly in mineralocorticoid target tissues such as kidney and colon, acts only as a dehydrogenase by producing inactive cortisone, and has been found to protect the mineralocorticoid receptor from high levels of receptor-active cortisol. Recently, 11beta-HSD 1 has become highly topical due to the finding that 11beta-HSD 1 plays a pivotal role in the pathogenesis of central obesity and the appearance of the metabolic syndrome. This review provides an overview on the components involved in GC signalling of 11beta-HSD type 1 as an important pre-receptor control enzyme that modulates activation of the GR.