Molecular mechanisms of glucocorticoid action: what is important?

Glucocorticoid Receptor-mediated transactivation is hampered by Striatin-3, a novel interaction partner of the receptor

The transcriptional activity of the glucocorticoid receptor (GR) is co-determined by its ability to recruit a vast and varying number of cofactors. We here identify Striatin-3 (STRN3) as a novel interaction partner of GR that interferes with GR’s ligand-dependent transactivation capacity. Remarkably, STRN3 selectively affects only GR-dependent transactivation and leaves GR-dependent transrepression mechanisms unhampered. We found that STRN3 down-regulates GR transactivation by an additional recruitment of the catalytic subunit of protein phosphatase 2A (PPP2CA) to GR. We hypothesize the existence of a functional trimeric complex in the nucleus, able to dephosphorylate GR at serine 211, a known marker for GR transactivation in a target gene-dependent manner. The presence of STRN3 appears an absolute prerequisite for PPP2CA to engage in a complex with GR. Herein, the C-terminal domain of GR is essential, reflecting ligand-dependency, yet other receptor parts are also needed to create additional contacts with STRN3.

Mechanistic Multi-Tissue Modeling of Glucocorticoid-Induced Leucine Zipper Regulation: Integrating Circadian Gene Expression with Receptor-Mediated Corticosteroid Pharmacodynamics

The glucocorticoid-induced leucine zipper (GILZ) is an important mediator of anti-inflammatory corticosteroid action. The pharmacokinetic/pharmacodynamic/pharmacogenomic effects of acute and chronic methylprednisolone (MPL) dosing on the tissue-specific dynamics of GILZ expression were examined in rats. A mechanism-based model was developed to investigate and integrate the role of MPL and circadian rhythms on the transcriptional enhancement of GILZ in multiple tissues. Animals received a single 50-mg/kg intramuscular bolus or a 7-day 0.3-mg/kg/h subcutaneous infusion of MPL and were euthanized at several time points. An additional group of rats were euthanized at several times and served as 24-hour light/dark (circadian) controls. Plasma MPL and corticosterone concentrations were measured by high-performance liquid chromatography. The expression of GILZ and glucocorticoid receptor (GR) mRNA was quantified in tissues using quantitative real-time reverse-transcription polymerase chain reaction. The pharmacokinetics of MPL were described using a two-compartment model. Mild-to-robust circadian oscillations in GR and GILZ mRNA expression were characterized in muscle, lung, and adipose tissues and modeled using Fourier harmonic functions. Acute MPL dosing caused significant down-regulation (40%-80%) in GR mRNA and enhancement of GILZ mRNA expression (500%-1080%) in the tissues examined. While GILZ returned to its rhythmic baseline following acute dosing, a new steady-state was observed upon enhancement by chronic dosing. The model captured the complex dynamics in all tissues for both dosing regimens. The model quantitatively integrates physiologic mechanisms, such as circadian processes and GR tolerance phenomena, which control the tissue-specific regulation of GILZ by corticosteroids. These studies characterize GILZ as a pharmacodynamic marker of corticosteroid actions in several tissues.

Effects of Cellular 11β-hydroxysteroid Dehydrogenase 1 on LPS-induced Inflammatory Responses in Synovial Cell Line, SW982

11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) catalyzes the conversion of inactive cortisone into active cortisol, which has pleiotropic roles in various biological conditions, such as immunological and metabolic homeostasis. Cortisol is mainly produced in the adrenal gland, but can be locally regenerated in the liver, fat, and muscle. Its diverse actions are primarily mediated by binding to the glucocorticoid receptor. SW982, a human synovial cell line, expresses 11β-HSD type 1, but not type 2, that catalyzes the conversion of cortisone to cortisol. In this study, therefore, we investigated the control of lipopolysaccharide (LPS)-induced inflammatory responses by prereceptor regulation-mediated maintenance of cortisol levels. Preliminarily, cell seeding density and incubation period were optimized for analyzing the catalytic activity of SW982. Additionally, cellular 11β-HSD1 still remained active irrespective of monolayer or spheroid culture conditions. Inflammatory stimulants, such as interleukin (IL)-1β, tumor necrosis factor (TNF)α, and LPS, did not affect the catalytic activity of 11β-HSD1, although a high dose of LPS significantly decreased its activity. Additionally, autocrine effects of cortisol on inflammatory responses were investigated in LPS-stimulated SW982 cells. LPS upregulated pro-inflammatory cytokines, including IL-6 and IL-1β, in SW982 cells, while cortisol production, catalyzed by cellular 11β-HSD1, downregulated LPS-stimulated cytokines. Furthermore, suppression of NFκB activation-mediated pro-inflammatory responses by cortisol was revealed. In conclusion, the activity of cellular 11β-HSD1 was closely correlated with suppression of LPS-induced inflammation. Therefore, these results partly support the notion that prereceptor regulation of locally regenerated cortisol could be taken into consideration for treatment of inflammation-associated diseases, including arthritis.

A Quantitative Study of Internal and External Interactions of Homodimeric Glucocorticoid Receptor Using Fluorescence Cross-Correlation Spectroscopy in a Live Cell

Glucocorticoid receptor (GRα) is a well-known ligand-dependent transcription-regulatory protein. The classic view is that unliganded GRα resides in the cytoplasm, relocates to the nucleus after ligand binding, and then associates with a specific DNA sequence, namely a glucocorticoid response element (GRE), to activate a specific gene as a homodimer. It is still a puzzle, however, whether GRα forms the homodimer in the cytoplasm or in the nucleus before DNA binding or after that. To quantify the homodimerization of GRα, we constructed the spectrally different fluorescent protein tagged hGRα and applied fluorescence cross-correlation spectroscopy. First, the dissociation constant (K_d) of mCherry₂-fused hGRα or EGFP-fused hGRα was determined in vitro. Then, K_d of wild-type hGRα was found to be 3.00 μM in the nucleus, which was higher than that in vitro. K_d of a DNA-binding-deficient mutant was 3.51 μM in the nucleus. This similarity indicated that GRα homodimerization was not necessary for DNA binding but could take place on GRE by means of GRE as a scaffold. Moreover, cytoplasmic homodimerization was also observed using GRα mutated in the nuclear localization signal. These findings support the existence of a dynamic monomer pathway and regulation of GRα function both in the cytoplasm and nucleus.

Inhaled corticosteroids have a protective effect against lung cancer in female patients with chronic obstructive pulmonary disease: a nationwide population-based cohort study

Whether the use of inhaled corticosteroids (ICS) protects patients with chronic obstructive pulmonary disease (COPD) from lung cancer remains undetermined. In this retrospective nationwide population-based cohort study, we extracted data of 13,686 female COPD patients (ICS users, n = 1,290, ICS non-users, n = 12,396) diagnosed between 1997 and 2009 from the Taiwan's National Health Insurance database. These patients were followed-up until 2011, and lung cancer incidence was determined. Cox regression analysis was used to estimate hazard ratios (HRs) for lung cancer incidence. The time to lung cancer diagnosis was significantly different between ICS users and non-users (10.75 vs. 9.68 years, P < 0.001). Per 100,000 person-years, the lung cancer incidence rate was 235.92 for non-users and 158.67 for users [HR = 0.70 (95% confidence interval {CI}: 0.46-1.09)]. After adjusting for patients' age, income, and comorbidities, a cumulative ICS dose > 39.48 mg was significantly associated with a lower risk of lung cancer [ICS users > 39.48 mg, HR = 0.45 (95% CI: 0.21-0.96)]. Age ≥ 60 years, pneumonia, diabetes mellitus, and hypertension decreased lung cancer risk, whereas pulmonary tuberculosis increased the risk. Our results suggest that ICS have a potential role in lung cancer prevention among female COPD patients.

Immunosuppressive drugs affect interferon (IFN)-γ and programmed cell death 1 (PD-1) kinetics in patients with newly diagnosed autoimmune hepatitis

Autoimmune hepatitis (AIH) is characterized by overwhelming effector immune responses associated with defective regulatory T cells (T_regs ). Several lines of evidence indicate CD4 as the main effectors involved in autoimmune liver damage. Herein we investigate the in-vitro effects of prednisolone, 6-mercaptopurine, cyclosporin, tacrolimus, mycophenolic acid (MPA) and rapamycin, immunosuppressive drugs (ISDs) used in AIH treatment, on the expression of proinflammatory cytokines, co-inhibitory molecules and ability to proliferate of CD4⁺ CD25^- cells, isolated from the peripheral blood of treatment-naive patients with AIH. We note that in healthy subjects (HS) following polyclonal stimulation and in the absence of ISDs, the expression of interferon (IFN)-γ, interleukin (IL)-17 and tumour necrosis factor (TNF)-α by CD4 effectors peaks at 48 h and decreases at 96 h to reach baseline levels. In contrast, in AIH the expression of all these proinflammatory cytokines continue rising between 48 and 96 h. Levels of programmed cell death-1 (PD-1), T cell immunoglobulin and mucin domain-containing molecule-3 (TIM-3) and cytotoxic T lymphocyte antigen-4 (CTLA-4) increase over 96-h culture both in HS and AIH, although with faster kinetics in the latter. Exposure to ISDs contains IFN-γ and PD-1 expression in AIH, where control over CD4⁺ CD25^- cell proliferation is also noted upon exposure to MPA. Treatment with tacrolimus and cyclosporin render CD4⁺ CD25^- cells more susceptible to T_reg control. Collectively, our data indicate that in treatment-naive patients with AIH, all ISDs restrain T helper type 1 (Th1) cells and modulate PD-1 expression. Furthermore, they suggest that tacrolimus and cyclosporin may ameliorate effector cell responsiveness to T_regs .

Dexamethasone treatment decreases replication of viral hemorrhagic septicemia virus in Epithelioma papulosum cyprini cells

The expression of Mx1 in EPC cells after treatment with poly(I:C) or infection with viral hemorrhagic septicemia virus (VHSV) was significantly suppressed by treatment with dexamethasone. However, the titer of VHSV did not increase but instead decreased after dexamethasone treatment. This suggests that dexamethasone not only downregulates type I IFN but also affects certain factors that are necessary for VHSV replication. An important effect of HSP90 on replication of RNA viruses and downregulation of HSP90 by glucocorticoids have been reported. In this study, dexamethasone downregulated HSP90α expression in EPC cells that were stimulated with poly(I:C) or infected with VHSV. Furthermore, cells treated with an HSP90 inhibitor, geldanamycin, showed significantly decreased titers of VHSV, suggesting that HSP90 may be an important host component involved in VHSV replication, and HSP90 inhibition might be one of the causes for the observed reduction in viral titer caused by dexamethasone treatment.

Protective Roles for RGS2 in a Mouse Model of House Dust Mite-Induced Airway Inflammation

The GTPase-accelerating protein, regulator of G-protein signalling 2 (RGS2) reduces signalling from G-protein-coupled receptors (GPCRs) that signal via Gαq. In humans, RGS2 expression is up-regulated by inhaled corticosteroids (ICSs) and long-acting β2-adrenoceptor agonists (LABAs) such that synergy is produced in combination. This may contribute to the superior clinical efficacy of ICS/LABA therapy in asthma relative to ICS alone. In a murine model of house dust mite (HDM)-induced airways inflammation, three weeks of intranasal HDM (25 μg, 3×/week) reduced lung function and induced granulocytic airways inflammation. Compared to wild type animals, Rgs2-/- mice showed airways hyperresponsiveness (increased airways resistance and reduced compliance). While HDM increased pulmonary inflammation observed on hematoxylin and eosin-stained sections, there was no difference between wild type and Rgs2-/- animals. HDM-induced mucus hypersecretion was also unaffected by RGS2 deficiency. However, inflammatory cell counts in the bronchoalveolar lavage fluid of Rgs2-/- animals were significantly increased (57%) compared to wild type animals and this correlated with increased granulocyte (neutrophil and eosinophil) numbers. Likewise, cytokine and chemokine (IL4, IL17, IL5, LIF, IL6, CSF3, CXCLl, CXCL10 and CXCL11) release was increased by HDM exposure. Compared to wild type, Rgs2-/- animals showed a trend towards increased expression for many cytokines/chemokines, with CCL3, CCL11, CXCL9 and CXCL10 being significantly enhanced. As RGS2 expression was unaffected by HDM exposure, these data indicate that RGS2 exerts tonic bronchoprotection in HDM-induced airways inflammation. Modest anti-inflammatory and anti-remodelling roles for RGS2 are also suggested. If translatable to humans, therapies that maximize RGS2 expression may prove advantageous.

Anti-Inflammatory Effects of Protein Kinase Inhibitor Pyrrol Derivate

In our previous studies we showed antitumor and anti-inflammatory activities of protein kinases inhibitor pyrrol derivate 1-(4-Cl-benzyl)-3-Cl-4-(CF3-fenylamino)-1H-pyrrol-2,5-dione (MI-1) on rat colon cancer model. Therefore anti-inflammatory effect of MI-1 on rat acetic acid induced ulcerative colitis (UC) model was aimed to be discovered. The anti-inflammatory effects of MI-1 (2.7 mg/kg daily) compared to reference drug Prednisolone (0.7 mg/kg daily) after 14-day usage were evaluated on macro- and light microscopy levels and expressed in 21-grade scale. Redox status of bowel mucosa was also estimated. It was shown that in UC group the grade of total injury (GTI) was equal to 9.6 (GTI_control = 0). Increase of malonic dialdehyde (MDA) by 89% and protein carbonyl groups (PCG) by 60% and decrease of superoxide dismutase (SOD) by 40% were also observed. Prednisolone decreased GTI to 3 and leveled SOD activity, but MDA and PCG remained higher than control ones by 52% and 42%, respectively. MI-1 restored colon mucosa integrity and decreased mucosa inflammation down to GTI = 0.5 and leveled PCG and SOD. Thus, MI-1 possessed anti-inflammatory properties, which were more expressed that Prednisolone ones, as well as normalized mucosa redox balance, and so has a prospect for correction of inflammatory processes.

INVITED REVIEW: The usefulness of measuring glucocorticoids for assessing animal welfare

Glucocorticoids (corticosterone in birds and rodents and cortisol in all other mammals) are glucoregulatory hormones that are synthesized in response to a range of stimuli including stress and are regularly measured in the assessment of animal welfare. Glucocorticoids have many normal or non-stress-related functions, and glucocorticoid synthesis can increase in response to pleasure, excitement, and arousal as well as fear, anxiety, and pain. Often, when assessing animal welfare, little consideration is given to normal non-stress-related glucocorticoid functions or the complex mechanisms that regulate the effects of glucocorticoids on physiology. In addition, it is rarely acknowledged that increased glucocorticoid synthesis can indicate positive welfare states or that a stress response can increase fitness and improve the welfare of an animal. In this paper, we review how and when glucocorticoid synthesis increases, the actions mediated through type I and type II glucocorticoid receptors, the importance of corticosteroid-binding globulin, the role of 11 β-hydroxysteroid dehydrogenase, and the key aspects of neurophysiology relevant to activating the hypothalamo-pituitary-adrenal axis. This is discussed in the context of animal welfare assessment, particularly under the biological functioning and affective states frameworks. We contend that extending the assessment of animal welfare to key brain regions afferent to the hypothalamus and incorporating the aspects of glucocorticoid physiology that affect change in target tissue will advance animal welfare science and inspire more comprehensive assessment of the welfare of animals.

Glucocorticoid-Induced Leucine Zipper in Central Nervous System Health and Disease

The central nervous system (CNS) is a large network of intercommunicating cells that function to maintain tissue health and homeostasis. Considerable evidence suggests that glucocorticoids exert both neuroprotective and neurodegenerative effects on the CNS. Glucocorticoids act by binding two related receptors in the cytoplasm, the mineralocorticoid receptor (MR) and the glucocorticoid receptor (GR). The glucocorticoid receptor complex mediates cellular responses by transactivating target genes and by protein: protein interactions. The paradoxical effects of glucocorticoids on neuronal survival and death have been attributed to the concentration and the ratio of mineralocorticoid to glucocorticoid receptor activation. Glucocorticoid-induced leucine zipper (GILZ) is a recently identified protein transcriptionally upregulated by glucocorticoids. Constitutively, expressed in many tissues including brain, GILZ mediates many of the actions of glucocorticoids. It mimics the anti-inflammatory and anti-proliferative effects of glucocorticoids but exerts differential effects on stem cell differentiation and lineage development. Recent experimental data on the effects of GILZ following induced stress or trauma suggest potential roles in CNS diseases. Here, we provide a short overview of the role of GILZ in CNS health and discuss three potential rationales for the role of GILZ in Alzheimer's disease pathogenesis.

Understanding how long-acting β2 -adrenoceptor agonists enhance the clinical efficacy of inhaled corticosteroids in asthma - an update

In moderate-to-severe asthma, adding an inhaled long-acting β₂ -adenoceptor agonist (LABA) to an inhaled corticosteroid (ICS) provides better disease control than simply increasing the dose of ICS. Acting on the glucocorticoid receptor (GR, gene NR3C1), ICSs promote anti-inflammatory/anti-asthma gene expression. In vitro, LABAs synergistically enhance the maximal expression of many glucocorticoid-induced genes. Other genes, including dual-specificity phosphatase 1(DUSP1) in human airways smooth muscle (ASM) and epithelial cells, are up-regulated additively by both drug classes. Synergy may also occur for LABA-induced genes, as illustrated by the bronchoprotective gene, regulator of G-protein signalling 2 (RGS2) in ASM. Such effects cannot be produced by either drug alone and may explain the therapeutic efficacy of ICS/LABA combination therapies. While the molecular basis of synergy remains unclear, mechanistic interpretations must accommodate gene-specific regulation. We explore the concept that each glucocorticoid-induced gene is an independent signal transducer optimally activated by a specific, ligand-directed, GR conformation. In addition to explaining partial agonism, this realization provides opportunities to identify novel GR ligands that exhibit gene expression bias. Translating this into improved therapeutic ratios requires consideration of GR density in target tissues and further understanding of gene function. Similarly, the ability of a LABA to interact with a glucocorticoid may be suboptimal due to low β₂ -adrenoceptor density or biased β₂ -adrenoceptor signalling. Strategies to overcome these limitations include adding-on a phosphodiesterase inhibitor and using agonists of other Gs-coupled receptors. In all cases, the rational design of ICS/LABA, and derivative, combination therapies requires functional knowledge of induced (and repressed) genes for therapeutic benefit to be maximized.

The Non-Conventional Effects of Glucocorticoids in Cancer

Synthetic corticosteroids are widely used for the treatment of a variety of diseases, including pre-malignant and malignant conditions. In striking contrast, recent evidence suggests that corticosteroids can bear tumor-promoting effects in solid tumors of epithelial origin. We have recently shown that epithelial tissues, including the mucosa of the oral cavity and the skin, are able to modulate the local concentration of active corticosteroids and to produce steroids de novo. This has important clinical and physiopathological implications, because tissue-specific regulation of glucocorticoids plays a key role in the overall effect of these molecules. In the present review of the current English literature, performed using MEDLINE/PubMed/Ovid databases, we collected published evidence to demonstrate that corticosteroids induce effects that are more complex and controversial than previously acknowledged. Published studies clearly demonstrate that this class of molecules influences pathophysiological processes that are strictly related to malignancy, providing the rationale for further investigation. J. Cell. Physiol. 231: 2368-2373, 2016. © 2016 Wiley Periodicals, Inc.

RNA sequencing analysis of human podocytes reveals glucocorticoid regulated gene networks targeting non-immune pathways

Glucocorticoids are steroids that reduce inflammation and are used as immunosuppressive drugs for many diseases. They are also the mainstay for the treatment of minimal change nephropathy (MCN), which is characterised by an absence of inflammation. Their mechanisms of action remain elusive. Evidence suggests that immunomodulatory drugs can directly act on glomerular epithelial cells or ‘podocytes’, the cell type which is the main target of injury in MCN. To understand the nature of glucocorticoid effects on non-immune cell functions, we generated RNA sequencing data from human podocyte cell lines and identified the genes that are significantly regulated in dexamethasone-treated podocytes compared to vehicle-treated cells. The upregulated genes are of functional relevance to cytoskeleton-related processes, whereas the downregulated genes mostly encode pro-inflammatory cytokines and growth factors. We observed a tendency for dexamethasone-upregulated genes to be downregulated in MCN patients. Integrative analysis revealed gene networks composed of critical signaling pathways that are likely targeted by dexamethasone in podocytes.

Bronchoprotection and bronchorelaxation in asthma: New targets, and new ways to target the old ones

Despite over 50years of inhaled beta-agonists and corticosteroids as the default management or rescue drugs for asthma, recent research suggests that new therapeutic options are likely to emerge. This belief stems from both an improved understanding of what causes and regulates airway smooth muscle (ASM) contraction, and the identification of new targets whose inhibition or activation can relax ASM. In this review we discuss the recent findings that provide new insight into ASM contractile regulation, a revolution in pharmacology that identifies new ways to "tune" G protein-coupled receptors to improve therapeutic efficacy, and the discovery of several novel targets/approaches capable of effecting bronchoprotection or bronchodilation.

Discovery of Compound A--a selective activator of the glucocorticoid receptor with anti-inflammatory and anti-cancer activity

Glucocorticoids are among the most effective anti-inflammatory drugs, and are widely used for cancer therapy. Unfortunately, chronic treatment with glucocorticoids results in multiple side effects. Thus, there was an intensive search for selective glucocorticoid receptor (GR) activators (SEGRA), which retain therapeutic potential of glucocorticoids, but with fewer adverse effects. GR regulates gene expression by transactivation (TA), by binding as homodimer to gene promoters, or transrepression (TR), via diverse mechanisms including negative interaction between monomeric GR and other transcription factors. It is well accepted that metabolic and atrophogenic effects of glucocorticoids are mediated by GR TA. Here we summarized the results of extensive international collaboration that led to discovery and characterization of Compound A (CpdA), a unique SEGRA with a proven “dissociating” GR ligand profile, preventing GR dimerization and shifting GR activity towards TR both in vitro and in vivo. We outlined here the unusual story of compound's discovery, and presented a comprehensive overview of CpdA ligand properties, its anti-inflammatory effects in numerous animal models of inflammation and autoimmune diseases, as well as its anti-cancer effects. Finally, we presented mechanistic analysis of CpdA and glucocorticoid effects in skin, muscle, bone, and regulation of glucose and fat metabolism to explain decreased CpdA side effects compared to glucocorticoids. Overall, the results obtained by our and other laboratories underline translational potential of CpdA and its derivatives for treatment of inflammation, autoimmune diseases and cancer.

An inhaled dose of budesonide induces genes involved in transcription and signaling in the human airways: enhancement of anti- and proinflammatory effector genes

Although inhaled glucocorticoids, or corticosteroids (ICS), are generally effective in asthma, understanding their anti‐inflammatory actions in vivo remains incomplete. To characterize glucocorticoid‐induced modulation of gene expression in the human airways, we performed a randomized placebo‐controlled crossover study in healthy male volunteers. Six hours after placebo or budesonide inhalation, whole blood, bronchial brushings, and endobronchial biopsies were collected. Microarray analysis of biopsy RNA, using stringent (≥2‐fold, 5% false discovery rate) or less stringent (≥1.25‐fold, P ≤ 0.05) criteria, identified 46 and 588 budesonide‐induced genes, respectively. Approximately two third of these genes are transcriptional regulators (KLF9, PER1, TSC22D3, ZBTB16), receptors (CD163, CNR1, CXCR4, LIFR, TLR2), or signaling genes (DUSP1, NFKBIA, RGS1, RGS2, ZFP36). Listed genes were qPCR verified. Expression of anti‐inflammatory and other potentially beneficial genes is therefore confirmed and consistent with gene ontology (GO) terms for negative regulation of transcription and gene expression. However, GO terms for transcription, signaling, metabolism, proliferation, inflammatory responses, and cell movement were also associated with the budesonide‐induced genes. The most enriched functional cluster indicates positive regulation of proliferation, locomotion, movement, and migration. Moreover, comparison with the budesonide‐induced expression profile in primary human airway epithelial cells shows considerable cell type specificity. In conclusion, increased expression of multiple genes, including the transcriptional repressor, ZBTB16, that reduce inflammatory signaling and gene expression, occurs in the airways and blood and may contribute to the therapeutic efficacy of ICS. This provides a previously lacking insight into the in vivo effects of ICS and should promote strategies to improve glucocorticoid efficacy in inflammatory diseases.

Heart Transplantation

Although the number of available donor hearts severely limits the epidemiologic impact of heart transplantation on patients with heart failure, patients with end-stage heart failure unresponsive to medical management currently have no other viable alternatives. Destination therapy with a ventricular assist device is the closest toward approaching clinical reality but has been plagued with problems of infection and stroke. The purpose of this review is to summarize recent developments in the field that may broaden the clinical impact of heart transplantation. For example, novel methods of cardiac preservation are being designed to safely evaluate and utilize “extended criteria” donors. Surgical techniques and medical management have reduced the incidence of postoperative right heart failure, and immunosuppressive regimens promise to limit chronic graft vascular disease.

The effect of pre-operative methylprednisolone on the incidence of delayed graft function in renal transplantation

Introduction:

This study explores the effect of different corticosteroid administration timings on the incidence of slow/delayed graft function.

Methods:

One hundred and twelve kidney transplants from January 2011 to March 2014 were retrospectively analysed. Thirty-six cases were excluded because they were donor-specific antibody positive ( n=16), received thymoglobulin/plasma exchange ( n=11), were ABO-incompatible ( n=6) or suffered graft loss from vascular thrombosis within the first week post-transplant ( n=3). The study period straddled three eras of corticosteroid administration, from intra-operative intravenous (IV) hydrocortisone (Era 1; n=26), to intra-operative IV methylprednisolone (Era 2; n=38) and pre-operative IV methylprednisolone (Era 3; n=12). The primary endpoint was the incidence of slow/delayed graft function. Secondary outcomes included estimated glomerular filtration rate at discharge and 120 and 365 days, rejection (acute and one-year), wound complications, post-transplant diabetes, increase in low-density lipoprotein or body mass index, and cytomegalovirus or BK viraemia within one year.

Results:

On univariate analysis, pre-operative methylprednisolone was associated with lower incidence of slow/delayed graft function (17%, 55%, 58% in Eras 3, 2, 1 respectively; p=0.041), superior estimated glomerular filtration rate at discharge (median 56, 37 and 43 ml/min for Eras 3, 2, 1 respectively; p=0.033) and at 120 days (median 60, 52, and 46 ml/min for Eras 3, 2, 1 respectively; p=0.017). On multivariate analysis, pre-operative IV methylprednisolone ( vs. Eras 1 and 2 combined; odds ratio 4.79 (90% confidence interval 1.16–19.80); p=0.07) and living donor type ( vs. deceased; odds ratio 5.56 (90% confidence interval 2.25–13.77); p=0.002) were associated with lower incidence of slow/delayed graft function.

Conclusion:

Pre-operative methylprednisolone was associated with reduced slow/delayed graft function and improved early estimated glomerular filtration.

Short- and long-term exposure to alternating magnetic field (50 Hz, 0.5 mT) affects rat pituitary ACTH cells: Stereological study

The aim of the present study was to determine does extremely low frequency magnetic field (ELF-MF, 50 Hz, 0.5 mT) affect pituitary adrenocorticotroph (ACTH) cells in adult animals. We performed two series of experiments: (1) short-term exposure of 3-month-old rats to ELF-MF for 1 and 7 days, and (2) long-term exposure of rats to ELF-MF from their conception to 3 months of age. Stereological study was performed on immunolabeled pituitary ACTH cells. The total number and volume of ACTH cells, the volume of their nuclei and pituitary volume were measured. ELF-MF exposure for 1 day significantly decreased total number and volume of ACTH cells, the volume of their nuclei, as well as pituitary volume. ELF-MF exposure for 7 days significantly reduced only the volume of ACTH cells. Life-long exposure to ELF-MF induced decrease in the volume of ACTH cells and pituitary volume. We can conclude that the applied ELF-MF has a strong influence on morphometrical parameters of the pituitary ACTH cells and could be considered as a stressogenic factor.

Balancing the Budget: Accounting for Glucocorticoid Bioactivity and Fate during Water Treatment

Numerous studies have identified the presence and bioactivity of glucocorticoid receptor (GR) active substances in water; however, the identification and activity-balance of GR compounds remained elusive. This study determined the occurrence and attenuation of GR bioactivity and closed the balance by determining those substances responsible. The observed in vitro GR activity ranged from 39 to 155 ng dexamethasone-equivalent/L (ng Dex-EQ/L) in the secondary effluents of four wastewater treatment plants. Monochromatic ultraviolet light of 80 mJ/cm(2) disinfection dose was efficient for GR activity photolysis, whereas chlorination could not appreciably attenuate the observed GR activity. Ozonation was effective only at relatively high dose (ozone/TOC 1:1). Microfiltration membranes were not efficient for GR activity attenuation; however, reverse osmosis removed GR activity to levels below the limits of detection. A high-sensitivity liquid chromatography with tandem mass spectrometry (LC-MS/MS) method was then developed to screen 27 GR agonists. Twelve were identified and quantified in effluents at summed concentrations of 9.6-21.2 ng/L. The summed Dex-EQ of individual compounds based on their measured concentrations was in excellent agreement with the Dex-EQ obtained from bioassay, which demonstrated that the detected glucocorticoids can entirely explain the observed GR bioactivity. Four synthetic glucocorticoids (triamcinolone acetonide, fluocinolone acetonide, clobetasol propionate, and fluticasone propionate) predominantly accounted for GR activity. These data represent the first known publication where a complete activity balance has been determined for GR agonists in an aquatic environment.

Glucocorticoid-induced changes in glucocorticoid receptor mRNA and protein expression in the human placenta as a potential factor for altering fetal growth and development

Glucocorticoids (GCs) control essential metabolic processes in virtually every cell in the body and play a vital role in the development of fetal tissues and organ systems. The biological actions of GCs are mediated via glucocorticoid receptors (GRs), the cytoplasmic transcription factors that regulate the transcription of genes involved in placental and fetal growth and development. Several experimental studies have demonstrated that fetal exposure to high maternal GC levels early in gestation is associated with adverse fetal outcomes, including low birthweight, intrauterine growth restriction and anatomical and structural abnormalities that may increase the risk of cardiovascular, metabolic and neuroendocrine disorders in adulthood. The response of the fetus to GCs is dependent on gender, with female fetuses becoming hypersensitive to changes in GC levels whereas male fetuses develop GC resistance in the environment of high maternal GCs. In this paper we review GR function and the physiological and pathological effects of GCs on fetal development. We propose that GC-induced changes in the placental structure and function, including alterations in the expression of GR mRNA and protein levels, may play role in inhibiting in utero fetal growth.

Transcriptional Regulation of Human Transforming Growth Factor-α in Astrocytes

Transforming growth factor-alpha (TGF-α) is known to play multifunctional roles in the central nervous system (CNS), including the provision of neurotropic properties that protect neurons against various neurotoxic insults. Previously, we reported that TGF-α mediates estrogen-induced enhancement of glutamate transporter GLT-1 function in astrocytes. However, the regulatory mechanism of TGF-α at the transcriptional level remains to be established. Our findings revealed that the human TGF-α promoter contains consensus sites for several transcription factors, such as NF-κB and yin yang 1 (YY1). NF-κB served as a positive regulator of TGF-α promoter activity, corroborated by observations that overexpression of NF-κB p65 increased, while mutation in the NF-κB binding sites in the TGF-α promoter reduced the promoter activity in rat primary astrocytes. Pharmacological inhibition of NF-κB with pyrrolidine dithiocarbamate (PDTC; 50 μM) or quinazoline (QNZ; 10 μM) also abolished TGF-α promoter activity, and NF-κB directly bound to its consensus site in the TGF-α promoter as evidenced by electrophoretic mobility shift assay (EMSA). Dexamethasone (DX) increased TGF-α promoter activity by activation of NF-κB. Treatment of astrocytes with 100 nM of DX for 24 h activated its glucocorticoid receptor and signaling proteins, including MAPK, PI3K/Akt, and PKA, via non-genomic pathways, to enhance TGF-α promoter activity and expression. YY1 served as a critical negative regulator of the TGF-α promoter as overexpression of YY1 decreased, while mutation of YY1 binding site in the promoter increased TGF-α promoter activity. Treatment for 3 h with 250 μM of manganese (Mn), an environmental neurotoxin, decreased astrocytic TGF-α expression by activation of YY1. Taken together, our results suggest that NF-κB is a critical positive regulator, whereas YY1 is a negative regulator of the TGF-α promoter. These findings identify potential molecular targets for neurotherapeutics that may modulate TGF-α regulation and afford neuroprotection.

Leukocyte Subset Changes in Response to a 164-km Road Cycle Ride in a Hot Environment

The purpose of this observational study was to determine the circulating leukocyte subset response to completing the 2013 Hotter'N Hell Hundred recreational 164-km road cycle event in a hot and humid environmental condition. Twenty-eight men and four women were included in this study. Whole blood samples were obtained 1-2 hours before (PRE) and immediately after (POST) the event. Electronic sizing/sorting and cytometry were used to determine complete blood counts (CBC) including neutrophil, monocyte, and lymphocyte subsets. The concentration of circulating total leukocytes (10³·μL^-1) increased 134% from PRE to POST with the greatest increase in neutrophils (319%, p<0.0001). Circulating monocytes (including macrophages) increased 24% (p=0.004) and circulating lymphocytes including B and T cells increased 53% (p<0.0001). No association was observed between rolling time or relative intensity and leukocyte subset. Completing the Hotter n' Hell Hundred (HHH), a 100 mile recreational cycling race in extreme (hot and humid) environmental conditions, induces a substantial increase in total leukocytes in circulation. The contribution of increases in specific immune cell subsets is not equal, with neutrophils increasing to greater than 4-fold starting values from PRE to POST race. It is likely that exercise in stressful environmental conditions affects the complement of circulating immune cells, although activational state and characterization of specific leukocyte subsets remains unclear. The observed increase in circulating cell sub-populations suggests that the circulating immune surveillance system may be acutely affected by exercise in hot and humid conditions.

The Basal NPO crh Fluctuation is Sustained Under Compromised Glucocorticoid Signaling in Diurnal Zebrafish

The circadian activity of the hypothalamo-pituitary-adrenal/interrenal (HPA/I) axis is crucial for maintaining vertebrate homeostasis. In mammals, both the principle regulator, corticotropin-releasing hormone (crh) in the hypothalamic paraventricular nucleus (PVN) and the final effector, the glucocorticoids show daily rhythmic patterns. While glucocorticoids are the main negative regulator of PVN crh under stress, whether they modulate the PVN crh rhythm under basal condition is unclear in diurnal animals. Using zebrafish larvae, a recently-established diurnal model organism suited for the HPA/I axis and homeostasis research, we ask if glucocorticoid changes are required to maintain the daily variation of PVN crh. We first characterized the development of the HPI axis overtime and showed that the basal activity of the HPI axis is robust and tightly regulated by circadian cue in 6-day old larvae. We demonstrated a negative correlation between the basal cortisol and neurosecretory preoptic area (NPO) crh variations. To test if cortisol drives NPO crh variation, we analyzed the NPO crh levels in glucorcorticoid antagonist-treated larvae and mutants lacking circadian cortisol variations. We showed that NPO crh basal fluctuation is sustained although the level was decreased without proper cortisol signaling in zebrafish. Our data indicates that glucocorticoids do not modulate the basal NPO crh variations but may be required for maintaining overall NPO crh levels. This further suggests that under basal and stress conditions the HPA/I axis activity is modulated differently by glucocorticoids.

Negative Feed-forward Control of Tumor Necrosis Factor (TNF) by Tristetraprolin (ZFP36) Is Limited by the Mitogen-activated Protein Kinase Phosphatase, Dual-specificity Phosphatase 1 (DUSP1): IMPLICATIONS FOR REGULATION BY GLUCOCORTICOIDS

TNF is central to inflammation and may play a role in the pathogenesis of asthma. The 3'-untranslated region of the TNF transcript contains AU-rich elements (AREs) that are targeted by the RNA-binding protein, tristetraprolin (also known as zinc finger protein 36 (ZFP36)), which is itself up-regulated by inflammatory stimuli, to promote mRNA degradation. Using primary human bronchial epithelial and pulmonary epithelial A549 cells, we confirm that interleukin-1β (IL1B) induces expression of dual-specificity phosphatase 1 (DUSP1), ZFP36, and TNF. Whereas IL1B-induced DUSP1 is involved in feedback control of MAPK pathways, ZFP36 exerts negative (incoherent) feed-forward control of TNF mRNA and protein expression. DUSP1 silencing increased IL1B-induced ZFP36 expression at 2 h and profoundly repressed TNF mRNA at 6 h. This was partly due to increased TNF mRNA degradation, an effect that was reduced by ZFP36 silencing. This confirms a regulatory network, whereby DUSP1-dependent negative feedback control reduces feed-forward control by ZFP36. Conversely, whereas DUSP1 overexpression and inhibition of MAPKs prevented IL1B-induced expression of ZFP36, this was associated with increased TNF mRNA expression at 6 h, an effect that was predominantly due to elevated transcription. This points to MAPK-dependent feed-forward control of TNF involving ZFP36-dependent and -independent mechanisms. In terms of repression by dexamethasone, neither silencing of DUSP1, silencing of ZFP36, nor silencing of both together prevented the repression of IL1B-induced TNF expression, thereby demonstrating the need for further repressive mechanisms by anti-inflammatory glucocorticoids. In summary, these data illustrate why understanding the competing effects of feedback and feed-forward control is relevant to the development of novel anti-inflammatory therapies.

Highly Selective Artificial Cholesteryl Crown Ether K(+)-Channels

The bacterial KcsA channel conducts K(+) cations at high rates while excluding Na(+) cations. Herein, we report an artificial ion-channel formed by H-bonded stacks of crown-ethers, where K(+) cation conduction is highly preferred to Na(+) cations. The macrocycles aligned along the central pore surround the K(+) cations in a similar manner to the water around the hydrated cation, compensating for the energetic cost of their dehydration. In contrast, the Na(+) cation does not fit the macrocyclic binding sites, so its dehydration is not completely compensated. The present highly K(+)-selective macrocyclic channel may be regarded as a biomimetic of the KcsA channel.

Pharmacotherapy of critical asthma syndrome: current and emerging therapies

The critical asthma syndrome (CAS) encompasses the most severe, persistent, refractory asthma patients for the clinician to manage. Personalized pharmacotherapy is necessary to prevent the next acute severe asthma exacerbation, not just the control of symptoms. The 2007 National Asthma Education and Prevention Program Expert Panel 3 provides guidelines for the treatment of uncontrolled asthma. The patient's response to recommended pharmacotherapy is highly variable which risks poor asthma control leading to frequent exacerbations that can deteriorate into CAS. Controlling asthma symptoms and preventing acute exacerbations may be two separate clinical activities with their own unique demands. Clinicians must be prepared to use the entire spectrum of asthma medications available but must concurrently be aware of potential drug toxicities some of which can paradoxically worsen asthma control. Medications normally prescribed for COPD can potentially be useful in the CAS patient, particularly those with asthma-COPD overlap syndrome. Immunomodulation with drugs like omalizumab in IgE-mediated asthma syndromes is one important approach. New and emerging drugs address unique aspects of airway inflammation and biology but at a significant financial cost. The pharmacology and toxicities of the agents that may be used in the treatment of CAS to control asthma symptoms and prevent severe exacerbations are reviewed.

The acute management of asthma

Patients presenting to the emergency department (ED) or clinic with acute exacerbation of asthma (AEA) can be very challenging varying in both severity and response to therapy. High-dose, frequent or continuous nebulized short-acting beta2 agonist (SABA) therapy that can be combined with a short-acting muscarinic antagonist (SAMA) is the backbone of treatment. When patients do not rapidly clinically respond to SABA/SAMA inhalation, the early use of oral or parenteral corticosteroids should be considered and has been shown to impact the immediate need for ICU admission or even the need for hospital admission. Adjunctive therapies such as the use of intravenous magnesium and helium/oxygen combination gas for inhalation and for driving a nebulizer to deliver a SABA and or SAMA should be considered and are best used early in the treatment plan if they are likely to impact the patients' clinical course. The use of other agents such as theophylline, leukotriene modifiers, inhaled corticosteroids, long-acting beta2 agonist, and long-acting muscarinic antagonist currently does not play a major role in the immediate treatment of AEA in the clinic or the ED but is an important therapeutic option for physicians to be aware of and to consider initiating at the time of discharge from clinic, hospital, or ED to reduce later clinical worsening and readmission to the ED and hospital. A comprehensive summary is provided of the currently available respiratory pharmaceuticals approved for asthma and other airway syndromes. Clinicians must be prepared to use the entire spectrum of medications available for the treatment of acute asthma exacerbations and the agents that should be initiated to prevent worsening or additional exacerbations. They need to be familiar with the major potential drug toxicities associated with their use.

Relative contribution of P450c17 towards the acute cortisol response: Lessons from sheep and goats

The rapid release of cortisol from the adrenal cortex upon ACTH receptor activation plays an integral role in the stress response. It has been suggested that the quantitative control over adrenal steroidogenesis (quantity of total steroids produced) depends on the activities of cytochrome P450 side-chain cleavage and steroidogenic acute regulatory protein that supplies pregnenolone precursor to the pathway. The qualitative control (which steroids) then depends on the downstream steroidogenic enzymes, including cytochrome P450 17α-hydroxylase/17,20-lyase (P450c17). In this review we focus on the relative contribution of P450c17 in the qualitative control of cortisol production with data collected from studies on South African Angora and Boer goats, as well as Merino sheep. Unique P450c17 genotypes were identified in these breeds with isoforms differing only with a couple of single amino acid residue substitutions. This review demonstrates how molecular and cellular differences relating to P450c17 activity can affect physiological and behavioural responses.

Quantitative tissue-specific dynamics of in vivo GILZ mRNA expression and regulation by endogenous and exogenous glucocorticoids

Glucocorticoids (GC) are steroid hormones, which regulate metabolism and immune function. Synthetic GCs, or corticosteroids (CS), have appreciable clinical utility via their ability to suppress inflammation in immune-mediated diseases like asthma and rheumatoid arthritis. Recent work has provided insight to novel GC-induced genes that mediate their anti-inflammatory effects, including glucocorticoid-induced leucine zipper (GILZ). Since GILZ comprises an important part of GC action, its regulation by both drug and hormone will influence CS therapy. In addition, GILZ expression is often employed as a biomarker of GC action, which requires judicious selection of sampling time. Understanding the in vivo regulation of GILZ mRNA expression over time will provide insight into both the physiological regulation of GILZ by endogenous GC and the dynamics of its enhancement by CS. A highly quantitative qRT-PCR assay was developed for measuring GILZ mRNA expression in tissues obtained from normal and CS-treated rats. This assay was applied to measure GILZ mRNA expression in eight tissues; to determine its endogenous regulation over time; and to characterize its dynamics in adipose tissue, muscle, and liver following treatment with CS. We demonstrate that GILZ mRNA is expressed in several tissues. GILZ mRNA expression in adipose tissue displayed a robust circadian rhythm that was entrained with the circadian oscillation of endogenous corticosterone; and is strongly enhanced by acute and chronic dosing. Single dosing also enhanced GILZ mRNA in muscle and liver, but the dynamics varied. In conclusion, GILZ is widely expressed in the rat and highly regulated by endogenous and exogenous GCs.

Stress in Atlantic salmon: response to unpredictable chronic stress

Combinations of stressors occur regularly throughout an animal's life, especially in agriculture and aquaculture settings. If an animal fails to acclimate to these stressors, stress becomes chronic, and a condition of allostatic overload arises with negative results for animal welfare. In the current study, we describe effects of exposing Atlantic salmon parr to an unpredictable chronic stressor (UCS) paradigm for 3 weeks. The paradigm involves exposure of fish to seven unpredictable stressors three times a day. At the end of the trial, experimental and control fish were challenged with yet another novel stressor and sampled before and 1 h after that challenge. Plasma cortisol decreased steadily over time in stressed fish, indicative of exhaustion of the endocrine stress axis. This was confirmed by a lower cortisol response to the novel stressor at the end of the stress period in chronically stressed fish compared with the control group. In the preoptic area (POA) and pituitary gland, chronic stress resulted in decreased gene expression of 11βhsd2, gr1 and gr2 in the POA and increased expression of those genes in the pituitary gland. POA crf expression and pituitary expression of pomcs and mr increased, whereas interrenal gene expression was unaffected. Exposure to the novel stressor had no effect on POA and interrenal gene expression. In the pituitary, crfr1, pomcs, 11βhsd2, grs and mr were down-regulated. In summary, our results provide a novel overview of the dynamic changes that occur at every level of the hypothalamic-pituitary gland-interrenal gland (HPI) axis as a result of chronic stress in Atlantic salmon.

An intra-articular, extended-release formulation of triamcinolone acetonide prolongs and amplifies analgesic effect in patients with osteoarthritis of the knee: a randomized clinical trial

BACKGROUND

Intra-articular corticosteroids are a mainstay in the treatment of knee osteoarthritis, and in clinical trials, they demonstrate a large initial analgesic effect that wanes over one to four weeks with the rapid efflux of drug from the joint. The present study was undertaken to determine if FX006, an extended-release formulation of triamcinolone acetonide, can provide pain relief that is superior to the current standard of care, immediate-release triamcinolone acetonide.

METHODS

In this Phase-2, double-blind, multicenter study, 228 patients with moderate to severe knee osteoarthritis pain were randomized to a single intra-articular injection of FX006 (containing 10, 40, or 60 mg of triamcinolone acetonide) or 40 mg of immediate-release triamcinolone acetonide. Data on the mean daily pain on the 11-point Numeric Rating Scale were collected over twelve weeks; the primary efficacy end point was the change from baseline to each of eight, ten, and twelve weeks in the weekly mean of the mean daily pain intensity scores analyzed with a longitudinal mixed-effects model.

RESULTS

The 10-mg dose of FX006 produced pain relief that was improved relative to immediate-release triamcinolone acetonide at two through twelve weeks, although the difference in pain relief was not significant (p ≥ 0.05). The 40-mg dose of FX006 produced pain relief that was improved at two through twelve weeks and was significantly superior to immediate-release triamcinolone acetonide at five to ten weeks (p < 0.05 at each time point). At the 40-mg dose of FX006, prespecified secondary analyses, including responder analyses and all Western Ontario and McMaster Universities subscales, were significantly superior (p < 0.05) to immediate-release triamcinolone acetonide at eight weeks, and the time-weighted mean pain relief (assessed with mean daily pain intensity scores) was significantly superior to immediate-release triamcinolone acetonide over one to twelve weeks (p = 0.04). The 60-mg dose did not provide additional improvement relative to the 40-mg dose. Adverse events were generally mild and similar across all treatments.

CONCLUSIONS

Intra-articular injection of FX006, an extended-release formulation of triamcinolone acetonide, provided a clinically relevant improvement in pain relief in patients with knee osteoarthritis relative to immediate-release triamcinolone acetonide, the current standard of care.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Inhibition of 11β-Hydroxysteroid Dehydrogenase Type II Suppresses Lung Carcinogenesis by Blocking Tumor COX-2 Expression as Well as the ERK and mTOR Signaling Pathways

Lung cancer is by far the leading cause of cancer death. Early diagnosis and prevention remain the best approach to reduce the overall morbidity and mortality. Experimental and clinical evidence have shown that cyclooxygenase-2 (COX-2) derived prostaglandin E₂ (PGE2) contributes to lung tumorigenesis. COX-2 inhibitors suppress the development and progression of lung cancer. However, increased cardiovascular risks of COX-2 inhibitors limit their use in chemoprevention of lung cancers. Glucocorticoids are endogenous and potent COX-2 inhibitors, and their local actions are down-regulated by 11β–hydroxysteroid dehydrogenase type II (11ßHSD2)-mediated metabolism. We found that 11βHSD2 expression was increased in human lung cancers and experimental lung tumors. Inhibition of 11βHSD2 activity enhanced glucocorticoid-mediated COX-2 inhibition in human lung carcinoma cells. Furthermore, 11βHSD2 inhibition suppressed lung tumor growth and invasion in association with increased tissue active glucocorticoid levels, decreased COX-2 expression, inhibition of ERK and mTOR signaling pathways, increased tumor endoplasmic reticulum stress as well as increased lifespan. Therefore, 11βHSD2 inhibition represents a novel approach for lung cancer chemoprevention and therapy by increasing tumor glucocorticoid activity, which in turn selectively blocks local COX-2 activity and/or inhibits the ERK and mTOR signaling pathways.

Cholesterol-derived glucocorticoids control early fate specification in embryonic stem cells

Aside from its role in cell membrane integrity, cholesterol is a key component in steroid hormone production. The vital functions of steroid hormones such as estrogen, testosterone, glucocorticoids (Gcrts) and mineralocorticoids (Mnrts) in perinatal and adult life are well understood; however, their role during early embryonic development remains largely unexplored. Here we show that siRNA-mediated perturbation of steroid hormone production during mesoderm formation has important consequences on cardiac differentiation in mouse embryonic stem cells (mESC). Both Gcrts and Mnrts are capable of driving cardiac differentiation in mESC. Interestingly, the Gcrt receptor is widely expressed during gastrulation in the mouse, and is exclusively localized in the nuclei-and thus active-in visceral endoderm cells, suggesting that it functions much earlier than previously anticipated. We therefore studied Gcrt signaling in mESC as a model of the gastrulating embryo, and found that Gcrt signaling regulates expression of the transcription factor Hnf4a and the secreted Nodal and BMP inhibitor Cer1 in the early visceral endoderm. RNAi-mediated knockdown of Gcrt function blocked cardiomyocyte differentiation, with limited effects on other cardiovascular cell types including vascular endothelial cells and smooth muscle. Furthermore, the cardiogenic effect of Gcrts required Hnf4a and paracrine Cer1. These results establish a novel function for cholesterol-derived steroid hormones and identify Gcrt signaling in visceral endoderm cells as a regulator of Cer1 and cardiac fate.

Waterborne beclomethasone dipropionate affects the physiology of fish while its metabolite beclomethasone is not taken up

Asthma is commonly treated with inhalable glucocorticosteroids, including beclomethasone dipropionate (BDP). This is a synthetic prodrug which is metabolized to the more active monopropionate (BMP) and free beclomethasone in humans. To evaluate potential effects of residual drugs on fish, we conducted a 14 day flow-through exposure experiment with BDP and beclomethasone using rainbow trout, and analyzed effects on plasma glucose, hepatic glutathione and catalase activity together with water and body concentrations of the BDP, BMP and beclomethasone. We also analyzed hepatic gene expression in BDP-exposed fish by microarray and quantitative PCR. Beclomethasone (up to 0.65 μg/L) was not taken up in the fish while BDP (0.65 and 0.07 μg/L) resulted in accumulation of both beclomethasone, BMP and BDP in plasma, reaching levels up to those found in humans during therapy. Accordingly, exposure to 0.65 μg/L of BDP significantly increased blood glucose as well as oxidized glutathione levels and catalase activity in the liver. Exposure to beclomethasone or the low concentration of BDP had no effect on these endpoints. Both exposure concentrations of BDP resulted in significantly higher transcript abundance of phosphoenolpyruvate carboxykinase involved in gluconeogenesis, and of genes involved in immune responses. As only the rapidly metabolized prodrug was potent in fish, the environmental risks associated with the use of BDP are probably small. However, the observed physiological effects in fish of BDP at plasma concentrations known to affect human physiology provides valuable input to the development of read-across approaches in the identification of pharmaceuticals of environmental concern.

Hypothalamic-pituitary-adrenal axis function during perinatal depression

Abnormal function of the hypothalamic-pituitary-adrenal (HPA) axis is an important pathological finding in pregnant women exhibiting major depressive disorder. They show high levels of cortisol pro-inflammatory cytokines, hypothalamic-pituitary peptide hormones and catecholamines, along with low dehydroepiandrosterone levels in plasma. During pregnancy, the TH2 balance together with the immune system and placental factors play crucial roles in the development of the fetal allograft to full term. These factors, when altered, may generate a persistent dysfunction of the HPA axis that may lead to an overt transfer of cortisol and toxicity to the fetus at the expense of reduced activity of placental 11β-hydroxysteroid dehydrogenase type 2. Epigenetic modifications also may contribute to the dysregulation of the HPA axis. Affective disorders in pregnant women should be taken seriously, and therapies focused on preventing the deleterious effects of stressors should be implemented to promote the welfare of both mother and baby.

Structure of a 13-fold superhelix (almost) determined from first principles

Nuclear hormone receptors are cytoplasm-based transcription factors that bind a ligand, translate to the nucleus and initiate gene transcription in complex with a co-activator such as TIF2 (transcriptional intermediary factor 2). For structural studies the co-activator is usually mimicked by a peptide of circa 13 residues, which for the largest part forms an α-helix when bound to the receptor. The aim was to co-crystallize the glucocorticoid receptor in complex with a ligand and the TIF2 co-activator peptide. The 1.82 Å resolution diffraction data obtained from the crystal could not be phased by molecular replacement using the known receptor structures. HPLC analysis of the crystals revealed the absence of the receptor and indicated that only the co-activator peptide was present. The self-rotation function displayed 13-fold rotational symmetry, which initiated an exhaustive but unsuccessful molecular-replacement approach using motifs of 13-fold symmetry such as α- and β-barrels in various geometries. The structure was ultimately determined by using a single α-helix and the software ARCIMBOLDO, which assembles fragments placed by PHASER before using them as seeds for density modification model building in SHELXE. Systematic variation of the helix length revealed upper and lower size limits for successful structure determination. A beautiful but unanticipated structure was obtained that forms superhelices with left-handed twist throughout the crystal, stabilized by ligand interactions. Together with the increasing diversity of structural elements in the Protein Data Bank the results from TIF2 confirm the potential of fragment-based molecular replacement to significantly accelerate the phasing step for native diffraction data at around 2 Å resolution.

An analysis of glucocorticoid receptor-mediated gene expression in BEAS-2B human airway epithelial cells identifies distinct, ligand-directed, transcription profiles with implications for asthma therapeutics

BACKGROUND AND PURPOSE

International asthma guidelines recommend that inhaled glucocorticoids be used as a monotherapy in all patients with mild to moderate disease because of their ability to suppress airways inflammation. Current evidence suggests that the therapeutic benefit of glucocorticoids is due to the transactivation and transrepression of anti-inflammatory and pro-inflammatory genes respectively. However, the extent to which clinically relevant glucocorticoids are equivalent in their ability to modulate gene expression is unclear.

EXPERIMENTAL APPROACH

A pharmacodynamics investigation of glucocorticoid receptor (GR)-mediated gene transactivation in BEAS-2B human airway epithelial cells was performed using a glucocorticoid response element luciferase reporter coupled with an analysis of glucocorticoid-inducible genes encoding proteins with anti-inflammatory and adverse-effect potential.

KEY RESULTS

Using transactivation as a functionally relevant output, a given glucocorticoid displayed a unique, gene expression 'fingerprint' where intrinsic efficacy and GR density were essential determinants. We showed that depending on the gene selected for analysis, a given glucocorticoid can behave as an antagonist, partial agonist, full agonist or even 'super agonist'. In the likely event that different, tissue-dependent gene expression profiles are reproduced in vivo, then the anti-inflammatory and adverse-effect potential of many glucocorticoids currently available as asthma therapeutics may not be equivalent.

CONCLUSIONS AND IMPLICATIONS

The generation of gene expression 'fingerprints' in target and off-target human tissues could assist the rational design of GR agonists with improved therapeutic ratios. This approach could identify compounds that are useful in the management of severe asthma and other inflammatory disorders where systemic exposure is desirable.

Genomic and non-genomic effects of glucocorticoids: implications for breast cancer

Glucocorticoids (GC) are essential steroid hormones for human life. They regulate a series of important processes by binding with three glucocorticoid receptors (GR) and activating genomic and non-genomic pathways. Activated cytoplasmic GR can directly bind DNA and transactivate or transrepress specific genes. Additionally, it can interact with other transcription factors to affect gene expression indirectly. The two membrane GR can interact with mitogen-activated protein (MAP) kinases or activate cAMP and Ca(2+)-dependent pathways, respectively. Glucocorticoids have been widely used as co-treatment of patients with breast cancer (BC) due to reduction of chemotherapy-induced side effects such as nausea, lack of appetite, and inflammation. However, GC may exert a direct effect on tumor response to chemotherapy. In vitro, GC inhibits chemotherapy, radiation and cytokine-induced apoptosis by upregulating antiapoptotic genes and detoxifying proteins. They also upregulate the proto-oncogene c-fms, tumor suppressor gene Nm23, several members of the epidermal growth factor (EGF) signaling pathway and the estrogen sulfotransferase signaling pathway, thus indirectly inhibiting estrogen receptor activation. They inhibit the proangiogenic gene (vascular endothelial growth factor (VEGF); Therefore, they could play a role in reducing angiogenesis. Interestingly, the phosphorylation status of ser-211 in the GR is dependent on the expression of the BRCA1 gene, a tumor suppressor gene that is mutated in the majority of patients with triple negative BC. Some clinical randomized trials have also attempted to address the effect of GC on patients with BC. Thus, in this review we summarize GC mechanisms of action and their participation in several facets of BC.

Steroids for acute respiratory distress syndrome?

The development and severity of acute respiratory distress syndrome (ARDS) are closely related to dysregulated inflammation, and the duration of ARDS and eventual outcomes are related to persistent inflammation and abnormal fibroproliferation. Corticosteroids are potent modulators of inflammation and inhibitors of fibrosis that have been used since the first description of ARDS in attempts to improve outcomes. There is no evidence that corticosteroids prevent the development of ARDS among patients at risk. High-dose and short-course treatment with steroids does not improve the outcomes of patients with ARDS. Additional studies are needed to recommend treatment with steroids for ARDS.

Comprehensive assessment of proteins regulated by dexamethasone reveals novel effects in primary human peripheral blood mononuclear cells

Inflammation is a physiological process involved in many diseases. Monitoring proteins involved in regulatory effects may help to improve our understanding of inflammation. We have analyzed proteome alterations induced in peripheral blood mononuclear cells (PBMCs) upon inflammatory activation in great detail using high-resolution mass spectrometry. Moreover, the activated cells were treated with dexamethasone to investigate their response to this antiphlogistic drug. From a total of 6886 identified proteins, 469 proteins were significantly regulated upon inflammatory activation. Data are available via ProteomeXchange with identifiers PXD001415-23. Most of these proteins were counter-regulated by dexamethasone, with some exceptions concerning members of the interferon-induced protein family. To confirm some of these results, we performed targeted MRM analyses of selected peptides. The inflammation-induced upregulation of proteins such as IL-1β, IL-6, CXCL2, and GROα was confirmed, however, with strong quantitative interindividual differences. Furthermore, the inability of dexamethasone to downregulate inflammation-induced proteins such as PTX3 and TSG6 was clearly demonstrated. In conclusion, the relation of cell function as well as drug-induced modulation thereof was successfully mapped to proteomes, suggesting targeted analysis as a novel and powerful drug evaluation method. Although most consequences of dexamethasone were found to be compatible with the expected mode of action, some unexpected but significant observations may be related to adverse effects.

Superiority of combined phosphodiesterase PDE3/PDE4 inhibition over PDE4 inhibition alone on glucocorticoid- and long-acting β2-adrenoceptor agonist-induced gene expression in human airway epithelial cells

Glucocorticoids, also known as corticosteroids, induce effector gene transcription as a part of their anti-inflammatory mechanisms of action. Such genomic effects can be significantly enhanced by long-acting β2-adrenoceptor agonists (LABAs) and may contribute to the clinical superiority of inhaled corticosteroid (ICS)/LABA combinations in asthma and chronic obstructive pulmonary disease (COPD) over ICSs alone. Using models of cAMP- and glucocorticoid-induced transcription in human bronchial epithelial BEAS-2B cells, we show that combining inhibitors of phosphodiesterase (PDE) 3 and PDE4 provides greater benefits compared with inhibiting either PDE alone. In respect to cAMP-dependent transcription, inhibitors of PDE3 (siguazodan, cilostazol) and PDE4 (rolipram, GSK256066, roflumilast N-oxide) each sensitized to the LABA, formoterol. This effect was magnified by dual PDE3 and PDE4 inhibition. Siguazodan plus rolipram was also more effective at inducing cAMP-dependent transcription than either inhibitor alone. Conversely, the concentration-response curve describing the enhancement of dexamethasone-induced, glucocorticoid response element-dependent transcription by formoterol was displaced to the left by PDE4, but not PDE3, inhibition. Overall, similar effects were described for bona fide genes, including RGS2, CD200, and CRISPLD2. Importantly, the combination of siguazodan plus rolipram prolonged the duration of gene expression induced by formoterol, dexamethasone, or dexamethasone plus formoterol. This was most apparent for RGS2, a bronchoprotective gene that may also reduce the proinflammatory effects of constrictor mediators. Collectively, these data provide a rationale for the use of PDE3 and PDE4 inhibitors in the treatment of COPD and asthma where they may enhance, sensitize, and prolong the effects of LABA/ICS combination therapies.

Influence of chronic stress on brain corticosteroid receptors and HPA axis activity

BACKGROUND

Disruption of the glucocorticoid negative feedback system evoked in animals by chronic stress can be induced by downregulation of glucocorticoid receptors (GRs) in several brain regions. In the present study, the dynamics of the changes in GRs, in brain structures involved in stress reactions, prefrontal cortex, hippocampus and hypothalamus was compared with the peripheral hypothalamo-pituitary-adrenocortical (HPA) axis hormones response to chronic stress.

METHODS

Rats were exposed to 10 min restraint or restrained twice a day for 3, 7 or 14 days, and 24 h after the last stress session exposed to homotypic stress for 10 min. Control rats were not restrained. After rapid decapitation at 0, 1, 2, and 3 h after stress termination, trunk blood for plasma adrenocorticotropic hormone (ACTH) and corticosterone determinations was collected and prefrontal cortex, hippocampus and hypothalamus were excised and frozen. Plasma hormones were determined using commercially available kits and glucocorticoids and mineralocorticoids protein levels in brain structure samples were determined by western blot procedure.

RESULTS

Restraint stress alone significantly decreased glucocorticoid receptor (GR) level in prefrontal cortex and hippocampus, and increased mineralocorticoid receptor (MR) level in hypothalamus. Prior repeated stress for 3 days significantly increased GR protein level in hippocampus and diminished that level in hypothalamus in 7 days stressed rats. Acute stress-induced strong increase in plasma ACTH and corticosterone levels decreased to control level after 1 or 2 h, respectively. Prior repeated stress for 3 days markedly diminished the fall in plasma ACTH level and repeated stress for 7 days moderately deepened this decrease. Plasma ACTH level induced by homotypic stress in rats exposed to restraint for 3, 7, and 14 days did not markedly differ from its control level, whereas plasma corticosterone response was significantly diminished. The fast decrease of stress-induced high plasma ACTH and corticosterone levels was accompanied by a parallel decline of GR level only in prefrontal cortex but not in the hippocampus or hypothalamus.

CONCLUSIONS

Comparison of the dynamics of changes in plasma ACTH and corticosterone level with respective alterations in GR and MR in brain structures suggests that the buffering effect of repeated stress depends on the period of habituation to stress and the brain structure involved in regulation of these stress response.

Sex differences in stress-related psychiatric disorders: neurobiological perspectives

Stress is associated with the onset and severity of several psychiatric disorders that occur more frequently in women than men, including posttraumatic stress disorder (PTSD) and depression. Patients with these disorders present with dysregulation of several stress response systems, including the neuroendocrine response to stress, corticolimbic responses to negatively valenced stimuli, and hyperarousal. Thus, sex differences within their underlying circuitry may explain sex biases in disease prevalence. This review describes clinical studies that identify sex differences within the activity of these circuits, as well as preclinical studies that demonstrate cellular and molecular sex differences in stress responses systems. These studies reveal sex differences from the molecular to the systems level that increase endocrine, emotional, and arousal responses to stress in females. Exploring these sex differences is critical because this research can reveal the neurobiological underpinnings of vulnerability to stress-related psychiatric disorders and guide the development of novel pharmacotherapies.

Development of novel treatment strategies for inflammatory diseases-similarities and divergence between glucocorticoids and GILZ

Glucocorticoids (GC) are the most commonly prescribed medications for patients with inflammatory diseases, despite their well-known adverse metabolic effects. Previously, it was understood that the anti-inflammatory effects of the GC/GC receptor (GR) complex were mediated via transrepression, whilst the adverse metabolic effects were mediated via transactivation. It has recently become clear that this “divergent actions” paradigm of GC actions is likely insufficient. It has been reported that the GC/GR-mediated transactivation also contributes to the anti-inflammatory actions of GC, via up-regulation of key anti-inflammatory proteins. One of these is glucocorticoid-induced leucine zipper (GILZ), which inhibits inflammatory responses in a number of important immune cell lineages in vitro, as well as in animal models of inflammatory diseases in vivo. This review aims to compare the GILZ and GC effects on specific cell lineages and animal models of inflammatory diseases. The fact that the actions of GILZ permit a GILZ-based gene therapy to lack GC-like adverse effects presents the potential for development of new strategies to treat patients with inflammatory diseases.

Endobiogeny: a global approach to systems biology (part 2 of 2)

ENDOBIOGENY AND THE BIOLOGY OF FUNCTIONS ARE BASED ON FOUR SCIENTIFIC CONCEPTS THAT ARE KNOWN AND GENERALLY ACCEPTED: (1) human physiology is complex and multifactorial and exhibits the properties of a system; (2) the endocrine system manages metabolism, which is the basis of the continuity of life; (3) the metabolic activity managed by the endocrine system results in the output of biomarkers that reflect the functional achievement of specific aspects of metabolism; and (4) when biomarkers are related to each other in ratios, it contextualizes one type of function relative to another to which is it linked anatomically, sequentially, chronologically, biochemically, etc.

Roles for the mitogen-activated protein kinase (MAPK) phosphatase, DUSP1, in feedback control of inflammatory gene expression and repression by dexamethasone

Glucocorticoids act on the glucocorticoid receptor (NR3C1) to repress inflammatory gene expression. This is central to their anti-inflammatory effectiveness and rational improvements in therapeutic index depend on understanding the mechanism. Human pulmonary epithelial A549 cells were used to study the role of the mitogen-activated protein kinase (MAPK) phosphatase, dual-specificity phosphatase 1 (DUSP1), in the dexamethasone repression of 11 inflammatory genes induced, in a MAPK-dependent manner, by interleukin-1β (IL1B). Adenoviral over-expression of DUSP1 inactivated MAPK pathways and reduced expression of all 11 inflammatory genes. IL1B rapidly induced DUSP1 expression and RNA silencing revealed a transient role in feedback inhibition of MAPKs and inflammatory gene expression. With dexamethasone, which induced DUSP1 expression, plus IL1B (co-treatment), DUSP1 expression was further enhanced. At 1 h, this was responsible for the dexamethasone inhibition of IL1B-induced MAPK activation and CXCL1 and CXCL2 mRNA expression, with a similar trend for CSF2. Whereas, CCL20 mRNA was not repressed by dexamethasone at 1 h, repression of CCL2, CXCL3, IL6, and IL8 was unaffected, and PTGS2 repression was partially affected by DUSP1 knockdown. At later times, dexamethasone repression of MAPKs was unaffected by DUSP1 silencing. Likewise, 6 h post-IL1B, dexamethasone repression of all 11 mRNAs was essentially unaffected by DUSP1 knockdown. Qualitatively similar data were obtained for CSF2, CXCL1, IL6, and IL8 release. Thus, despite general roles in feedback inhibition, DUSP1 plays a transient, often partial, role in the dexamethasone-dependent repression of certain inflammatory genes. Therefore this also illustrates key roles for DUSP1-independent effectors in mediating glucocorticoid-dependent repression.