Mechanisms of glucocorticoid receptor signaling during inflammation

Carbenoxolone prevents chemical eye ischemia-reperfusion-induced cell death via 11β-hydroxysteroid dehydrogenase type 1 inhibition

Glaucoma is one of the leading causes of preventable blindness diseases, affecting more than 2 million people in the United States. Recently, 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) inhibitors were found to exert preventive effects against glaucoma. Therefore, we investigated whether carbenoxolone (CBX), an 11β-HSD1 inhibitor, prevents chemical ischemia-reperfusion-induced cell death in human trabecular meshwork (HTM) cells. The present study demonstrated that CBX inhibited cell death caused by iodoacetic acid (IAA)-induced ischemia-reperfusion, and its effect was associated with the inhibition of 11β-HSD1 expression and activity. Furthermore, CBX reversed the IAA-induced structural damage on filamentous actin in HTM cells. In IAA-treated cells, the levels of 11β-HSD1 and the apoptosis-related factors Bax and FASL were increased throughout the reperfusion period, and CBX was able to attenuate the expression of 11β-HSD1 and the apoptosis-related factors. CBX also effectively suppressed IAA-induced intracellular ROS formation and cytochrome c release, which are involved in the mitochondrial apoptosis pathway. In addition, IAA-induced chemical ischemia-reperfusion stimulated TNF-α expression and NF-κB p65 phosphorylation, and these effects were attenuated by CBX. 11β-HSD1 RNAi also suppressed IAA-induced cell apoptosis via reduction of oxidative stress and inhibition of the pro-inflammatory pathway. Taken together, the present study demonstrated that the inhibition of 11β-HSD1 protected the TM against chemical ischemia-reperfusion injury, suggesting that the use of 11β-HSD1 inhibitors could be a useful strategy for glaucoma therapy.

Epigenetic landscapes reveal transcription factors that regulate CD8+ T cell differentiation

Dynamic changes in the expression of transcription factors (TFs) can influence the specification of distinct CD8+ T cell fates, but the observation of equivalent expression of TFs among differentially fated precursor cells suggests additional underlying mechanisms. Here we profiled the genome-wide histone modifications, open chromatin and gene expression of naive, terminal-effector, memory-precursor and memory CD8+ T cell populations induced during the in vivo response to bacterial infection. Integration of these data suggested that the expression and binding of TFs contributed to the establishment of subset-specific enhancers during differentiation. We developed a new bioinformatics method using the PageRank algorithm to reveal key TFs that influence the generation of effector and memory populations. The TFs YY1 and Nr3c1, both constitutively expressed during CD8+ T cell differentiation, regulated the formation of terminal-effector cell fates and memory-precursor cell fates, respectively. Our data define the epigenetic landscape of differentiation intermediates and facilitate the identification of TFs with previously unappreciated roles in CD8+ T cell differentiation.

Flightless-I homolog regulates glucocorticoid receptor-mediated transcription via direct interaction of the leucine-rich repeat domain

Flightless-I homolog (FLII) is a member of the gelsolin family of proteins, and has been identified as a coactivator of estrogen receptor-mediated transcription. Here, we investigate the role of FLII in the glucocorticoid receptor (GR) signaling pathway. Reporter gene assay and real-time quantitative PCR in A549 were performed to investigate the function of FLII in the expression of GR target genes. Co-immunoprecipitation assay and in vitro binding assay were used to identify binding domain of FLII. Chromatin immunoprecipitation assay were carried out with FLII-depleted A549 cells to determine the role of FLII at GR binding sites. We demonstrate that FLII potentiates GR-mediated reporter gene activity synergistically with CARM1 and p300 to enhance GR transcriptional activity in the presence of dexamethasone (Dex) in A549 cells. Depletion of endogenous FLII inhibited the expression of Dex-regulated GR target genes in A549 cells, indicating that FLII is required for GR-mediated transcription. Further, we observed that FLII binds to GR via its N-terminal leucine-rich repeat (LRR) region, suggesting that the enhancement of GR activation may occur through the interaction of GR and FLII. Moreover, chromatin immunoprecipitation analysis demonstrated that FLII is recruited to the GR binding sites. In addition, depletion of endogenous FLII decreased the recruitment of p300, and subsequently RNA polymerase II, to specific sites of GR target genes. Taken together, these studies reveal a functional involvement of FLII in activating transcription of GR target genes, suggesting a physiological role for FLII in the GR signaling pathway.

A review of associated controversies surrounding glucocorticoid use in veterinary emergency and critical care

OBJECTIVE

To review the literature in human and veterinary medicine regarding the indications for, efficacy of, and controversies surrounding glucocorticoid (GC) administration in the emergency and critical care (ECC) setting, and to provide an overview of the most commonly used synthetic GC formulations.

MEDICATIONS

Synthetic GCs vary in GC and mineralocorticoid potency, hypothalamic pituitary axis suppression, duration of action, route of administration, and clinical indication for use. Some of the GC compounds commonly used in human and veterinary ECC include hydrocortisone, prednisone, methylprednisolone, and dexamethasone.

INDICATIONS FOR USE

GCs are used in human and veterinary ECC for a variety of disorders including anaphylaxis, acute lung injury/acute respiratory distress syndrome, septic shock, and spinal cord injury. Evidence for morbidity or mortality benefit with administration of GC within these populations exists; however, data are sparse and often conflicting.

ADVERSE EFFECTS AND CONTRAINDICATIONS

Routine use of GC in some conditions such as trauma, hemorrhagic shock, and traumatic brain injury is likely contraindicated. GC use has been associated with hyperglycemia, pneumonia, urinary tract infection, gastrointestinal ulceration, or increased mortality in some populations.

Angiopoietin-Like Protein 7 Promotes an Inflammatory Phenotype in RAW264.7 Macrophages Through the P38 MAPK Signaling Pathway

Angiopoietin-like protein 7 (Angptl7) has been extensively studied for decades, but its potential immune functions have not been characterized. Hence, we investigated the relationship between Angptl7 and inflammation by using RAW264.7 monocyte/macrophage cells. The expression of genes encoding inflammation-associated factors cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β), IL-6, IL-10, and transforming growth factor beta 1 (TGF-β1)) decreased after RAW264.7 cells were treated with anti-Angptl7 polyclonal antibody but increased after the cells were transfected with an Angptl7-expressing plasmid. Angptl7 overexpression enhanced phagocytosis and inhibited the proliferation of RAW264.7 cells. In addition, Angptl7 antagonized the anti-inflammatory effects of TGF-β1 and dexamethasone. Pathway analysis showed that Angptl7 promoted the phosphorylation of both p65 and p38, but only the P38 mitogen-activated protein kinase (MAPK) signaling pathway mediated Angptl7-associated inflammatory functions. Additionally, after 1 week of daily intraperitoneal injections of recombinant TNF-α in a mouse model of peripheral inflammation, Angptl7 expression increased in the mouse eyes. Thus, Angptl7 is a factor that promotes pro-inflammatory responses in macrophages through the P38 MAPK signaling pathway and represents a potential therapeutic target for treatment of inflammatory diseases.

Effects of the synthetic corticosteroid dexamethasone on bovine herpesvirus 1 productive infection

Sensory neurons are a primary site for life-long latency of bovine herpesvirus 1 (BoHV-1). The synthetic corticosteroid dexamethasone induces reactivation from latency and productive infection, in part because the BoHV-1 genome contains more than 100 glucocorticoid receptor (GR) responsive elements (GREs). Two GREs in the immediate early transcription unit 1 promoter are required for dexamethasone induction. Recent studies also demonstrated that the serum and glucocorticoid receptor protein kinase (SGK) family stimulated BoHV-1 replication. Consequently, we hypothesized that dexamethasone influences several aspects of productive infection. In this study, we demonstrated that dexamethasone increased expression of the immediate early protein bICP4, certain late transcripts, and UL23 (thymidine kinase) by four hours after infection. SGK1 expression and Akt phosphorylation were also stimulated during early stages of infection and dexamethasone treatment further increased this effect. These studies suggest that stress, as mimicked by dexamethasone treatment, has the potential to stimulate productive infection by multiple pathways.

Integration of VDR genome wide binding and GWAS genetic variation data reveals co-occurrence of VDR and NF-κB binding that is linked to immune phenotypes

Background

The nuclear hormone receptor superfamily acts as a genomic sensor of diverse signals. Their actions are often intertwined with other transcription factors. Nuclear hormone receptors are targets for many therapeutic drugs, and include the vitamin D receptor (VDR). VDR signaling is pleotropic, being implicated in calcaemic function, antibacterial actions, growth control, immunomodulation and anti-cancer actions. Specifically, we hypothesized that the biologically significant relationships between the VDR transcriptome and phenotype-associated biology could be discovered by integrating the known VDR transcription factor binding sites and all published trait- and disease-associated SNPs. By integrating VDR genome-wide binding data (ChIP-seq) with the National Human Genome Research Institute (NHGRI) GWAS catalog of SNPs we would see where and which target gene interactions and pathways are impacted by inherited genetic variation in VDR binding sites, indicating which of VDR’s multiple functions are most biologically significant.

Results

To examine how genetic variation impacts VDR function we overlapped 23,409 VDR genomic binding peaks from six VDR ChIP-seq datasets with 191,482 SNPs, derived from GWAS-significant SNPs (Lead SNPs) and their correlated variants (r² > 0.8) from HapMap3 and the 1000 genomes project. In total, 574 SNPs (71 Lead and 503 SNPs in linkage disequilibrium with Lead SNPs) were present at VDR binding loci and associated with 211 phenotypes. For each phenotype a hypergeometric test was used to determine if SNPs were enriched at VDR binding sites. Bonferroni correction for multiple testing across the 211 phenotypes yielded 42 SNPs that were either disease- or phenotype-associated with seven predominately immune related including self-reported allergy; esophageal cancer was the only cancer phenotype. Motif analyses revealed that only two of these 42 SNPs reside within a canonical VDR binding site (DR3 motif), and that 1/3 of the 42 SNPs significantly impacted binding and gene regulation by other transcription factors, including NF-κB. This suggests a plausible link for the potential cross-talk between VDR and NF-κB.

Conclusions

These analyses showed that VDR peaks are enriched for SNPs associated with immune phenotypes suggesting that VDR immunomodulatory functions are amongst its most important actions. The enrichment of genetic variation in non-DR3 motifs suggests a significant role for the VDR to bind in multimeric complexes containing other transcription factors that are the primary DNA binding component. Our work provides a framework for the combination of ChIP-seq and GWAS findings to provide insight into the underlying phenotype-associated biology of a given transcription factor.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-017-3481-4) contains supplementary material, which is available to authorized users.

Corticosterone Inhibits the Proliferation of C6 Glioma Cells via the Translocation of Unphosphorylated Glucocorticoid Receptor

Astroglial cells have been considered to have passive brain function by helping to maintain neurons. However, recent studies have revealed that the dysfunction of such passive functions may be associated with various neuropathological diseases, such as schizophrenia, Alzheimer's disease, amyotrophic lateral sclerosis and major depression. Corticosterone (CORT), which is often referred to as the stress hormone, is a well-known regulator of peripheral immune responses and also shows anti-inflammatory properties in the brain. However, it is still obscure how CORT affects astroglial cell function. In this study, we investigated the effects of CORT on the proliferation and survival of astroglial cells using C6 glioma cells. Under treatment with CORT for 24h, the proliferation of C6 glioma cells decreased in a dose-dependent manner. Moreover, this inhibition was diminised by treatment with mifepristone, a glucocorticoid receptor (GR) antagonist, but not by spironolactone, a mineralocorticoid receptor (MR) antagonist, and was independent of GR phosphorylation and other GR-related intracellular signaling cascades. Furthermore, it was observed that the translocation of GR from the cytosol to the nucleus was promoted by the treatment with CORT. These results indicate that CORT decreases the proliferation of C6 glioma cells by modifying the transcription of a particular gene related to cell proliferation independent of GR phosphorylation.

New Insights in Glucocorticoid Receptor Signaling-More Than Just a Ligand-Binding Receptor

The clinical use of classical glucocorticoids (GC) is narrowed by the many side effects it causes and the resistance to GC observed in some diseases. Since the great majority of GC effects depend on the activation of a glucocorticoid receptor (GR), many research groups had focused to better understand the signaling pathways involving those receptors. Transgenic animal models and genetic modifications of the receptor brought a huge insight into GR mechanisms of action. This in turn opened a new window for the search of selective GR modulators that ideally may have agonistic and antagonistic combined effects and activate one specific signaling pathway, inducing mostly transrepression or transactivation mechanisms. Another important research field concerns to posttranslational modifications that affect the GR and consequently also affect its signaling and function. In this mini review, we discuss many of those aspects of GR signaling, as well as findings like the ligand-independent activation of GR, which add another layer of complexity in GR signaling pathways. Although several recent data have been added to the GR field, much work has yet to be done, especially to find out the biological relevance of those alternative GR signaling pathways. Improving the knowledge about alternative GR signaling pathways and understanding how these pathways intercommunicate and in which situations they are relevant might help to develop new strategies to take benefit of it and to improve GC or other compounds efficacy causing minimal side effects.

Proinflammatory cytokines remain elevated despite long-term remission in Cushing's disease: a prospective study

CONTEXT

Inflammation contributes to the development of metabolic and cardiovascular disease. Cushing's disease (CD), a state of chronic glucocorticoid (GC) excess characterized by visceral obesity and insulin resistance, may be associated with increased systemic inflammation. Cardiovascular mortality in CD remains elevated even after successful remission. It is unclear whether a chronic low-grade inflammatory state persists even after remission of CD, which may account for the increased CVD mortality.

PURPOSE

(1) To assess circulating proinflammatory cytokines in patients with active CD and BMI-matched controls; (2) to prospectively follow plasma cytokine concentrations in patients with CD before and after surgical remission; and (3) to assess whether plasma cytokine concentrations correlate with adipose tissue distribution and ectopic lipid content in liver and muscle.

METHODS

Plasma cytokines from prospectively enrolled patients with CD (N = 31) were quantified during active disease (v1) vs controls (N = 18) and 19·5 ± 12·9 months after surgical remission (v2). Fasting plasma IL-6, IL-1β, TNF-α, IL-8, IL-17 and IL-10 were quantified using a multiplex assay. Total and regional fat masses were measured by whole-body MRI.

RESULTS

Circulating IL-6 and IL-1β were elevated in patients with active CD vs controls (P < 0·05) and remained elevated in CD after surgical remission, despite decreases in BMI (P < 0·001), HOMA-IR (P < 0·001), and visceral, hepatic and intermuscular fat (P < 0·001, <0·001 and 0·03, respectively).

CONCLUSIONS

Despite long-term remission and improvements in fat distribution and insulin sensitivity, patients with CD may suffer from a state of chronic low-grade inflammation, which could contribute to increased cardiovascular mortality.

Hall of Fame among Pro-inflammatory Cytokines: Interleukin-6 Gene and Its Transcriptional Regulation Mechanisms

Pro-inflammatory cytokines that are generated by immune system cells and mediate many kinds of immune responses are kinds of endogenous polypeptides. They are also the effectors of the autoimmune system. It is generally accepted that interleukin (IL)-4, IL-6, IL-9, IL-17, and tumor necrosis factor-α are pro-inflammatory cytokines; however, IL-6 becomes a protagonist among them since it predominately induces pro-inflammatory signaling and regulates massive cellular processes. It has been ascertained that IL-6 is associated with a large number of diseases with inflammatory background, such as anemia of chronic diseases, angiogenesis acute-phase response, bone metabolism, cartilage metabolism, and multiple cancers. Despite great progress in the relative field, the targeted regulation of IL-6 response for therapeutic benefits remains incompletely to be understood. Therefore, it is conceivable that understanding mechanisms of IL-6 from the perspective of gene regulation can better facilitate to determine the pathogenesis of the disease, providing more solid scientific basis for clinical treatment translation. In this review, we summarize the candidate genes that have been implicated in clinical target therapy from the perspective of gene transcription regulation.

Endothelial Response to Glucocorticoids in Inflammatory Diseases

The endothelium plays a crucial role in inflammation. A balanced control of inflammation requires the action of glucocorticoids (GCs), steroidal hormones with potent cell-specific anti-inflammatory properties. Besides the classic anti-inflammatory effects of GCs on leukocytes, recent studies confirm that endothelial cells also represent an important target for GCs. GCs regulate different aspects of endothelial physiology including expression of adhesion molecules, production of pro-inflammatory cytokines and chemokines, and maintenance of endothelial barrier integrity. However, the regulation of endothelial GC sensitivity remains incompletely understood. In this review, we specifically examine the endothelial response to GCs in various inflammatory diseases ranging from multiple sclerosis, stroke, sepsis, and vasculitis to atherosclerosis. Shedding more light on the cross talk between GCs and endothelium will help to improve existing therapeutic strategies and develop new therapies better tailored to the needs of patients.

Antioxidant activities of ginsenoside Rg1 against cisplatin-induced hepatic injury through Nrf2 signaling pathway in mice

Oxidative stress is mainly caused by reactive oxygen species (ROS). The damage causes a net stress on normal organs, leading to a gradual loss of vital physiological function. ROS, such as free radicals, represent a class of molecules which are derived from the metabolism of oxygen and exist inherently. However, excessive produced ROS can damage all aerobic organisms. Ginseng is one of the most commonly used alternative herbal medicines, also as a traditional Chinese medicine. The aim of this study is to investigate the antioxidant potential function of ginsenoside Rg1 against cisplatin-caused hepatic damage. Male mice were treated with cisplatin to induce oxidative stress to mimic the side effect of anti-cancer drug cisplatin. Ginsenoside Rg1 effectively prevented against cisplatin-induced hepatotoxicity, alleviating histological lesions. Antioxidant functions of Rg1 were restrained by the activation of p62-Keap1-Nrf2 signaling pathway, simultaneously accompanied with expression of protein products. Accumulative p62 and increased activation of JNK in hepatocytes promoted the activation of Nrf2. For the other, degradation of Nrf2 was guided by tyrosine phosphorylation, ubiquitin, and Keap1. In summary, Rg1 prevents hepatotoxicity mainly by inhibiting the binding of Keap1 and Nrf2, partly by p62 accumulation, and more importantly by increasing the production of antioxidative proteins associated to Nrf2. Pharmacological activation of Nrf2 is an effective way in combating against liver injury.

Aluminum chloride induced splenic lymphocytes apoptosis through NF-κB inhibition

This research investigated the relationship between lymphocytes apoptosis, hypothalamic-pituitary-adrenal (HPA) axis and NF-κB in AlCl3-treated rats. Eighty Wistar rats were orally exposed to 0 (control group, CG), 0.4 mg/mL (low-dose group, LG), 0.8 mg/mL (mid-dose group, MG) and 1.6 mg/mL (high-dose group, HG) AlCl3 for 90 days, respectively. A variety of measurements were taken including lymphocyte apoptosis index, serum corticotropin-releasing hormone (CRH), adrenocorticotrophic hormone (ACTH) and glucocorticoids (GCs) contents, GC receptors (GCR) and NF-κB mRNA and nuclear protein expressions, caspase 3 and 9 mRNA expressions and activities. The results showed that in the AlCl3-treated rats serum CRH, ACTH and GCs contents, lymphocyte GC receptors (GCR) mRNA and nuclear protein expressions, caspase 3 and 9 mRNA expressions and activities increased, while Bcl-2/Bax ratio and NF-κB mRNA and nuclear protein expressions decreased compared with the CG. Furthermore GCR and NF-κB nuclear protein expressions were negatively correlated. And NF-κB mRNA expression was positively correlated with that of Bcl-2, but negatively correlated with that of Bax in AlCl3-treated rats. These findings indicated that AlCl3 activated HPA axis, then induced splenic lymphocytes apoptosis through NF-κB inhibition.

Systems Pharmacology Dissection of the Integrated Treatment for Cardiovascular and Gastrointestinal Disorders by Traditional Chinese Medicine

Though cardiovascular diseases (CVDs) and gastrointestinal disorders (GIDs) are different diseases associated with different organs, they are highly correlated clinically. Importantly, in Traditional Chinese Medicine (TCM), similar treatment strategies have been applied in both diseases. However, the etiological mechanisms underlying them remain unclear. Here, an integrated systems pharmacology approach is presented for illustrating the molecular correlations between CVDs and GIDs. Firstly, we identified pairs of genes that are associated with CVDs and GIDs and found that these genes are functionally related. Then, the association between 115 heart meridian (HM) herbs and 163 stomach meridian (SM) herbs and their combination application in Chinese patent medicine was investigated, implying that both CVDs and GIDs can be treated by the same strategy. Exemplified by a classical formula Sanhe Decoration (SHD) treating chronic gastritis, we applied systems-based analysis to introduce a drug-target-pathway-organ network that clarifies mechanisms of different diseases being treated by the same strategy. The results indicate that SHD regulated several pathological processes involved in both CVDs and GIDs. We experimentally confirmed the predictions implied by the effect of SHD for myocardial ischemia. The systems pharmacology suggests a novel integrated strategy for rational drug development for complex associated diseases.

Challenges to develop novel anti-inflammatory and analgesic drugs

Chronic inflammatory diseases and persistent pain of different origin represent common medical, social, and economic burden, and their pharmacotherapy is still an unresolved issue. Therefore, there is a great and urgent need to develop anti-inflammatory and analgesic agents with novel mechanisms of action, but it is a very challenging task. The main problem is the relatively large translational gap between the preclinical experimental data and the clinical results due to characteristics of the models, difficulties with the investigational techniques particularly for pain, as well as species differences in the mechanisms. We summarize here the current state-of-the-art medication and related ongoing strategies, and the novel targets with lead molecules under clinical development. The first members of the gold-standard categories, such as nonsteroidal anti-inflammatory drugs, glucocorticoids, and opioids, were introduced decades ago, and since then very few drugs with novel mechanisms of action have been successfully taken to the clinics despite considerable development efforts. Several biologics targeting different key molecules have provided breakthrough in some autoimmune/inflammatory diseases, but they are expensive, only parenterally available, their long-term side effects often limit their administration, and they do not effectively reduce pain. Some kinase inhibitors and phosphodiesterase-4 blockers have recently been introduced as new directions. There are in fact some promising novel approaches at different clinical stages of drug development focusing on transient receptor potential vanilloid 1/ankyrin 1 channel antagonism, inhibition of voltage-gated sodium/calcium channels, several enzymes (kinases, semicarbazide-sensitive amine oxidases, and matrix metalloproteinases), cytokines/chemokines, transcription factors, nerve growth factor, and modulation of several G protein-coupled receptors (cannabinoids, purinoceptors, and neuropeptides). WIREs Nanomed Nanobiotechnol 2017, 9:e1427. doi: 10.1002/wnan.1427 For further resources related to this article, please visit the WIREs website.

Epigenetics and the glucocorticoid receptor: A review of the implications in depression

Depression is a serious psychiatric disorder that effects at least 350 million people worldwide today. Dysregulation of the hypothalamic-pituitary-adrenal axis (HPAA) is a robust finding in the pathophysiology of depression. This dysregulation is hypothesized to result from altered central glucocorticoid receptor (GR) levels and/or function as a consequence of chronic glucocorticoid (GC) release, leading to receptor resistance. Pivotal animal and human research to date has identified that early life exposure to prolonged levels of GCs, stress and/or depression, can induce epigenetic modifications at key regions on the GR gene that lead to alterations in GR expression and function. Epigenetics provides an attractive mechanism to explain how ones' genes and environment can interact to produce different disease phenotypes. This review aims to compile the information that has been collected to date and to identify key areas for further investigation.

Role of testosterone in regulating induction of TNF-α in rat spleen via ERK signaling pathway

Spleen is a pivotal organ for regulating immune homeostasis. It has been shown that testosterone diminishes secretion of various inflammatory molecules under multiple conditions. However, the mechanisms of action of endogenous testosterone affecting immune responses in the spleen remain unknown. The aim of the present study was to evaluate the immune functions of the spleen in response to testosterone withdrawal after orchidectomy, and the impact of splenocytes on the bacterial endotoxin lipopolysaccharide (LPS)-induced secretion of inflammatory molecules. Male rats were divided into 3 groups, i.e. intact, orchidectomized (Orch) and orchidectomized plus replacement of testosterone propionate (TP) (Orch+TP). The Orch and Orch+TP rats underwent bilateral orchidectomy one week before TP replacement (2mg/kg body weight) or sesame oil in intact rats as controls for seven days. Orch resulted in a significant increase of spleen weight and basal secretion of nitric oxide (NO) from splenocytes. Additionally, LPS up-regulated cell proliferation and the secretion of tumor necrosis factor-alpha (TNF-α) in splenocytes of Orch rats. Orch further up-regulated phosphorylation of extracellular signal-regulated kinases. Interestingly, the plasma corticosterone concentration in the Orch group was higher than that in the intact and Orch+TP groups. Deficiency of testosterone-elevated TNF-α and NO secretion in response to LPS were confirmed in the rat splenocytes. Testosterone also significantly attenuated LPS-elicited release of TNF-α and NO in a dose-dependent manner. However, testosterone did not suppress splenic blastogenesis at doses in the 10(-10)-10(-7)M concentration range. In this context, testosterone might have a protective role against inflammatory responses in the spleen. The present study provides evidence to indicate that testosterone might modulate the immune system.

Antidepressant therapies inhibit inflammation and microglial M1-polarization

Macrophages and their counterparts in the central nervous system, the microglia, detect and subsequently clear microbial pathogens and injured tissue. These phagocytic cells alter and adapt their phenotype depending on their prime activity, i.e., whether they participate in acute defence against pathogenic organisms ('M1'-phenotype) or in clearing damaged tissues and performing repair activities ('M2'-phenotype). Stimulation of pattern recognition receptors by viruses (vaccines), bacterial membrane components (e.g., LPS), alcohol, or long-chain saturated fatty acids promotes M1-polarization. Vaccine or LPS administration to healthy human subjects can result in sickness symptoms and low mood. Alcohol abuse and abdominal obesity are recognized as risk factors for depression. In the M1-polarized form, microglia and macrophages generate reactive oxygen and nitrogen radicals to eradicate microbial pathogens. Inadvertently, also tetrahydrobiopterin (BH4) may become oxidized. This is an irreversible reaction that generates neopterin, a recognized biomarker for depression. BH4 is a critical cofactor for the synthesis of dopamine, noradrenaline, and serotonin, and its loss could explain some of the symptoms of depression. Based on these aspects, the suppression of M1-polarization would limit the inadvertent catabolism of BH4. In the current review, we evaluate the evidence that antidepressant treatments (monoamine reuptake inhibitors, PDE4 inhibitors, lithium, valproate, agomelatine, tianeptine, electroconvulsive shock, and vagus nerve stimulation) inhibit LPS-induced microglia/macrophage M1-polarization. Consequently, we propose that supplementation with BH4 could limit the reduction in central monoamine synthesis and might represent an effective treatment for depressed mood.

The serum and glucocorticoid-regulated protein kinases (SGK) stimulate bovine herpesvirus 1 and herpes simplex virus 1 productive infection

Serum and glucocorticoid-regulated protein kinases (SGK) are serine/threonine protein kinases that contain a catalytic domain resembling other protein kinases: AKT/protein kinase B, protein kinase A, and protein kinase C-Zeta for example. Unlike these constitutively expressed protein kinases, SGK1 RNA and protein levels are increased by growth factors and corticosteroids. Stress can directly stimulate SGK1 levels as well as stimulate bovine herpesvirus 1 (BoHV-1) and herpes simplex virus 1 (HSV-1) productive infection and reactivation from latency suggesting SGK1 can stimulate productive infection. For the first time, we provide evidence that a specific SGK inhibitor (GSK650394) significantly reduced BoHV-1 and HSV-1 replication in cultured cells. Proteins encoded by the three BoHV-1 immediate early genes (bICP0, bICP4, and bICP22) and two late proteins (VP16 and gE) were consistently reduced by GSK650394 during early stages of productive infection. In summary, these studies suggest SGK may stimulate viral replication following stressful stimuli.

Development and assessment of countermeasure formulations for treatment of lung injury induced by chlorine inhalation

Chlorine is a commonly used, reactive compound to which humans can be exposed via accidental or intentional release resulting in acute lung injury. Formulations of rolipram (a phosphodiesterase inhibitor), triptolide (a natural plant product with anti-inflammatory properties), and budesonide (a corticosteroid), either neat or in conjunction with poly(lactic:glycolic acid) (PLGA), were developed for treatment of chlorine-induced acute lung injury by intramuscular injection. Formulations were produced by spray-drying, which generated generally spherical microparticles that were suitable for intramuscular injection. Multiple parameters were varied to produce formulations with a wide range of in vitro release kinetics. Testing of selected formulations in chlorine-exposed mice demonstrated efficacy against key aspects of acute lung injury. The results show the feasibility of developing microencapsulated formulations that could be used to treat chlorine-induced acute lung injury by intramuscular injection, which represents a preferred route of administration in a mass casualty situation.

Obesity, Asthma, and the Microbiome

Obesity is a risk factor for asthma, but standard asthma drugs have reduced efficacy in the obese. Obesity alters the gastrointestinal microbial community structure. This change in structure contributes to some obesity-related conditions and also could be contributing to obesity-related asthma. Although currently unexplored, obesity may also be altering lung microbiota. Understanding the role of microbiota in obesity-related asthma could lead to novel treatments for these patients.

Stress-Related Immune Markers in Depression: Implications for Treatment

Major depression is a serious psychiatric disorder; however, the precise biological basis of depression still remains elusive. A large body of evidence implicates a dysregulated endocrine and inflammatory response system in the pathogenesis of depression. Despite this, given the heterogeneity of depression, not all depressed patients exhibit dysregulation of the inflammatory and endocrine systems. Evidence suggests that inflammation is associated with depression in certain subgroups of patients and that those who have experienced stressful life events such as childhood trauma or bereavement may be at greater risk of developing depression. Consequently, prolonged exposure to stress is thought to be a key trigger for the onset of a depressive episode. This review assesses the relationship between stress and the immune system, with a particular interest in the mechanisms by which stress impacts immune function, and how altered immune functioning, in turn, may lead to a feed forward cascade of multiple systems dysregulation and the subsequent manifestation of depressive symptomology. The identification of stress-related immune markers and potential avenues for advances in therapeutic intervention is vital. Changes in specific biological markers may be used to characterize or differentiate depressive subtypes or specific symptoms and may predict treatment response, in turn facilitating a more effective, targeted, and fast-acting approach to treatment.

Local corticosterone activation by 11β-hydroxysteroid dehydrogenase 1 in keratinocytes: the role in narrow-band UVB-induced dermatitis

Keratinocytes are known to synthesize cortisol through activation of the enzyme 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1). To confirm the function of 11β-HSD1 in keratinocytes during inflammation in vivo, we created keratinocyte-specific-11β-HSD1 knockout mice (K5-Hsd11b1-KO mice) and analyzed the response to narrow-band ultraviolet B (NB-UVB) irradiation. Firstly, we measured the mRNA and protein levels of 11β-HSD1 following NB-UVB irradiation and found that the expression of 11β-HSD1 in keratinocytes of mouse ear skin was enhanced at 3 and 24 hours after 250 mJ/cm(2), 500 mJ/cm(2), 1 J/cm(2), and 2 J/cm(2) NB-UVB irradiation. Next, we determined that 24 hours after exposure to 1 J/cm(2) NB-UVB irradiation, the numbers of F4/80-, CD45-, and Gr-1-positive cells were increased in K5-Hsd11b1-KO mice compared to wild type (WT) mice. Furthermore, the expression of the chemokine (C-X-C-motif) ligand 1 (CXCL1) and interleukin (IL)-6 was also significantly enhanced in NB-UVB-irradiated K5-Hsd11b1-KO mice compared with WT mice. In addition, activation of nuclear factor-kappa B (NF-κB) after NB-UVB irradiation was enhanced in K5-Hsd11b1-KO mice compared to that in WT mice. Thus, NB-UVB-induced inflammation is augmented in K5-Hsd11b1-KO mice compared with WT mice. These results indicate that 11β-HSD1 may suppress NB-UVB-induced inflammation via inhibition of NF-κB activation.

Childhood Bereavement and Type 1 Diabetes: a Danish National Register Study

BACKGROUND

Death of a close family member such as a parent or a sibling can cause prolonged stress and changes in the family structure that may have extensive social and health effects on a young child. The aim of this paper is to examine the rate of type 1 diabetes following bereavement due to death of a first-degree family member in early life.

METHODS

We used data from the Danish Civil Registration System (CRS) to identify singleton births in Denmark born 1 January 1980 through 31 December 2005, n = 1 740 245 and their next of kin. We categorised children as exposed to bereavement if they lost a mother, father or sibling from age 5 years onwards, the remaining children were considered unexposed. Children were followed until first diagnosis of diabetes, death, emigration, or 31 December 2010. We estimated incidence rate ratios (IRRs) from birth using log-linear Poisson regression models with person-years as an offset variable. Exposed children were followed up for an average of 9.1 years [standard deviation (SD) 6.7] and unexposed children were followed up for an average of 12.3 years (SD 7.3).

RESULTS

In our sample 94 943 children were exposed to bereavement, and 6110 cases of type 1 diabetes were identified. Bereavement was associated with an increased rate of type 1 diabetes when exposure onset began after 11 years of age (adjusted IRR 1.28, 95% confidence interval 1.08, 1.51).

CONCLUSION

We found some evidence to indicate an increase in the rate of type 1 diabetes among children exposed to bereavement when exposure occurred after 11 years of age.

Interferon-alpha-induced inflammation is associated with reduced glucocorticoid negative feedback sensitivity and depression in patients with hepatitis C virus

Major medical illnesses are associated with increased risk for depression and alterations in hypothalamic-pituitary-adrenal (HPA) axis function. Pathophysiological processes such as inflammation that occur as a part of medical illnesses and their treatments have been shown to cause depressive symptoms, and may also affect the HPA axis. We previously reported that patients with hepatitis C virus chronically administered interferon (IFN)-alpha develop increased evening plasma cortisol concentrations and a flattened diurnal cortisol slope, which correlated with increased tumor necrosis factor (TNF) and its soluble receptor 2 (sTNFR2). Increased TNF and sTNFR2 were further correlated with depression and fatigue scores. The current study examined whether flattened cortisol slope might be secondary to reduced glucocorticoid receptor (GR) sensitivity, by measuring glucocorticoid negative feedback to dexamethasone (DEX) administration followed by corticotropin releasing hormone (CRH) challenge. In an exploratory analysis, 28 male and female patients with hepatitis C virus were studied at baseline (Visit 1) and after 12weeks (Visit 2) of either IFN-alpha plus ribavirin (n=17) or no treatment (n=11). Patients underwent dexamethasone DEX-CRH challenge, neuropsychiatric assessments, and measurement of plasma TNF and sTNFR2 during each visit. IFN-alpha did not affect neuroendocrine responses following CRH but did increase post-DEX cortisol, which was correlated with flattening of the diurnal cortisol slope (r=0.57, p=0.002) and with increased depression scores (r=0.38, p=0.047). Furthermore, the change in post-DEX cortisol was associated with IFN-alpha-induced increase in sTNFR2 (r=0.51, p=006), which was in turn correlated with depression (r=0.63, p<0.001) and fatigue (r=0.51, p=0.005) scores. Whereas the relationship between sTNFR2 and depression scores were independent of the change in post-DEX cortisol, the correlation between post-DEX cortisol and depression scores was not significant when controlling for sTNFR2. These findings suggest that inflammation induced in patients with hepatitis C virus during IFN-alpha therapy precipitates decreased GR sensitivity to lead to a flattened diurnal cortisol slope. Decreased GR sensitivity may in turn further increase inflammation and its ultimate effects on behavior. Treatments that target inflammation and/or GR sensitivity may reduce depressive symptoms associated with medical illnesses.

Ginsenoside metabolite compound K exerts joint-protective effect by interfering with synoviocyte function mediated by TNF-α and Tumor necrosis factor receptor type 2

Ginsenoside metabolite compound K (CK), metabolite of the ginsenoside, is considered to exert numerous pharmacological efficacies of ginsenoside, including anti-inflammation and immunoregulatory effects. Rheumatoid arthritis (RA) is a multi-systemic autoimmune disease characterized by hyperplastic synovial membrane and systemic inflammation, which ultimately lead to progressive destructive inflammatory arthropathy. To evaluate the potential joint-protective effects of CK and the underlying mechanism, adjuvant arthritis (AA) was induced by complete Freund's adjuvant in rats. After the onset of arthritis, The effect of CK on AA rats was evaluated by histopathology of the joint. The proliferation of fibroblast-like synoviocyte(FLS) was assayed by the Cell Counting Kit-8.The migration of FLS was assayed by transwell migration assay. Cytokines in the supernatant from FLS were measured by ELISA kit. Expression of Tumor Necrosis Factor Receptor Type 1(TNFR1) and Tumor Necrosis Factor Receptor Type 2(TNFR2) were detected by immunostaining analysis and western blot analysis. CK (80mg/kg) significantly ameliorated the histopathological change of joint in AA rats, balanced the RANKL/OPG ratio and attenuated the proliferation and migration of AA-FLS. CK suppressed the secretion of proinflammatory cytokines TNF-α and downregulated the expression of TNFR2 on AA-FLS. In vitro CK also significantly suppressed proliferation, migration and secretion of AA-FLS mediated by TNF-α. Further studies showed that the effects of CK on AA-FLS were reversed by using glucocorticoid receptor (GR) antagonist (mifepristone). Our data suggest that CK exerts joint-protective effect by interfering with synoviocyte function mediated by TNF-α and TNFR2, and this effect may be mediated by GR.

An emphasis on molecular mechanisms of anti-inflammatory effects and glucocorticoid resistance

Glucocorticoids (GC) are universally accepted agents for the treatment of anti-inflammatory and immunosuppressive disorders. They are used in the treatment of rheumatic diseases and various inflammatory diseases such as allergy, asthma and sepsis. They bind with GC receptor (GR) and form GC-GR complex with the receptor and exert their actions. On activation the GC-GR complex up-regulates the expression of nucleus anti-inflammatory proteins called as transactivation and down-regulates the expression of cytoplasmic pro-inflammatory proteins called as transrepression. It has been observed that transactivation mechanisms are notorious for side effects and transrepressive mechanisms are identified for beneficial anti-inflammatory effects of GC therapy. GC hampers the function of numerous inflammatory mediators such as cytokines, chemokines, adhesion molecules, arachidonic acid metabolites, release of platelet-activating factor (PAF), inflammatory peptides and enzyme modulation involved in the process of inflammation. The GC resistance is a serious therapeutic problem and limits the therapeutic response of GC in chronic inflammatory patients. It has been observed that the GC resistance can be attributed to cellular microenvironment changes, as a consequence of chronic inflammation. Various other factors responsible for resistance have been identified, including alterations in both GR-dependent and GR-independent signaling pathways of cytokine action, hypoxia, oxidative stress, allergen exposure and serum-derived factors. The present review enumerates various aspects of inflammation such as use of GC for treatment of inflammation and its mechanism of action. Molecular mechanisms of anti-inflammatory action of GC and GC resistance, alternative anti-inflammatory treatments and new strategy for reversing the GC resistance have also been discussed.

Study of the immunomodulatory properties of gamithromycin and dexamethasone in a lipopolysaccharide inflammation model in calves

The aim of this study was to define the in vivo immunomodulatory properties of the macrolide antibiotic gamithromycin in calves, with respect to the acute phase response. Additionally, the corticosteroid dexamethasone was included as a positive control immunomodulatory drug. Both drugs, as well as their combination,were studied in a previously developed inflammation model,which was initiated by an intravenous lipopolysaccharide (LPS) challenge (0.5 μg/kg body weight). Twenty-four 4-week-old male Holstein Friesian calves were randomized into four groups: no pharmacological treatment (n = 6) or a pharmacological treatment with gamithromycin (n= 6), dexamethasone (n= 6) or their combination (n= 6) 1 h prior to LPS administration. Blood collection and clinical scoring were performed at regular time points until 72 h post LPS challenge. Plasma concentrations of selected cytokines (tumour necrosis factor-α (TNF-α) and interleukin 6 (IL-6)) and acute phase proteins (serum amyloid A and haptoglobin) were subsequently determined. Gamithromycin did not have any beneficial effect on the LPS-induced clinical signs (dyspnea, fever, anorexia and depression), nor on the studied inflammatory mediators. In the dexamethasone and combination groups, the occurrence of dyspnea and fever was not prominently influenced, although the calves recovered significantly faster from the challenge. Moreover, dexamethasone significantly inhibited the levels of TNF-α and IL-6, suggesting a key role for these cytokines in sickness behaviour. In conclusion, unlike dexamethasone, gamithromycin did not directly reduce cytokine release in an LPS inflammation model in calves.

Treatment of Cancer Pain by Targeting Cytokines

Inflammation is one of the most important causes of the majority of cancer symptoms, including pain, fatigue, cachexia, and anorexia. Cancer pain affects 17 million people worldwide and can be caused by different mediators which act in primary efferent neurons directly or indirectly. Cytokines can be aberrantly produced by cancer and immune system cells and are of particular relevance in pain. Currently, there are very few strategies to control the release of cytokines that seems to be related to cancer pain. Nevertheless, in some cases, targeted drugs are available and in use for other diseases. In this paper, we aim to review the importance of cytokines in cancer pain and targeted strategies that can have an impact on controlling this symptom.

Phenotype-dependent alteration of pathways and networks reveals a pure synergistic mechanism for compounds treating mouse cerebral ischemia

AIM

Our previous studies have showed that ursodeoxycholic acid (UA) and jasminoidin (JA) effectively reduce cerebral infarct volume in mice. In this study we explored the pure synergistic mechanism of these compounds in treatment of mouse cerebral ischemia, which was defined as synergistic actions specific for phenotype variations after excluding interference from ineffective compounds.

METHODS

Mice with focal cerebral ischemia were treated with UA, JA or a combination JA and UA (JU). Concha margaritifera (CM) was taken as ineffective compound. Cerebral infarct volume of the mice was determined, and the hippocampi were taken for microarray analysis. Particular signaling pathways and biological functions were enriched based on differentially expressed genes, and corresponding networks were constructed through Ingenuity Pathway Analysis.

RESULTS

In phenotype analysis, UA, JA, and JU significantly reduced the ischemic infarct volume with JU being superior to UA or JA alone, while CM was ineffective. As a result, 4 pathways enriched in CM were excluded. Core pathways in the phenotype-positive groups (UA or JA) were involved in neuronal homeostasis and neuropathology. JU-contributing pathways included all UA-contributing and the majority (71.7%) of JA-contributing pathways, and 10 new core pathways whose effects included inflammatory immunity, apoptosis and nervous system development. The functions of JU group included all functions of JA group, the majority (93.1%) of UA-contributing functions, and 3 new core functions, which focused on physiological system development and function.

CONCLUSION

The pure synergism between UA and JA underlies 10 new core pathways and 3 new core functions, which are involved in inflammation, immune responses, apoptosis and nervous system development.

Using corticosteroids to reshape the gut microbiome: implications for inflammatory bowel diseases

BACKGROUND

Commensal gut microbiota play an important role in regulating metabolic and inflammatory conditions. Reshaping intestinal microbiota through pharmacologic means may be a viable treatment option. We sought to delineate the functional characteristics of glucocorticoid-mediated alterations on gut microbiota and their subsequent repercussions on host mucin regulation and colonic inflammation.

METHODS

Adult male C57Bl/6 mice, germ-free, Muc2-heterozygote (±), or Muc2-knockout (-/-) were injected with dexamethasone, a synthetic glucocorticoid, for 4 weeks. Fecal samples were collected for gut microbiota analysis through 16S rRNA terminal restriction fragment length polymorphism and amplicon sequencing. Intestinal mucosa was collected for mucin gene expression studies. Germ-free mice were conventionalized with gut microbes from treated and nontreated groups to determine their functional capacities in recipient hosts.

RESULTS

Exposure to dexamethasone in wild-type mice led to substantial shifts in gut microbiota over a 4-week period. Furthermore, a significant downregulation of colonic Muc2 gene expression was observed after treatment. Muc2-knockout mice harbored a proinflammatory environment of gut microbes, characterized by the increase or decrease in prevalence of specific microbiota populations such as Clostridiales and Lactobacillaceae, respectively. This colitogenic phenotype was transmissible to IL10-knockout mice, a genetically susceptible model of colonic inflammatory disorders. Microbiota from donors pretreated with dexamethasone, however, ameliorated symptoms of inflammation.

CONCLUSIONS

Commensal gut bacteria may be a key mediator of the anti-inflammatory effects observed in the large intestine after glucocorticoid exposure. These findings underscore the notion that intestinal microbes comprise a "microbial organ" essential for host physiology that can be targeted by therapeutic approaches to restore intestinal homeostasis.

Immunomodulatory and immunorestorative activities of β-D-glucan-rich extract and polysaccharide fraction of mushroom, Pleurutus tuberregium

CONTEXT

Some edible mushrooms are reputed to possess useful medicinal properties which are related to their ability to modulate the protective responses of the immune system.

OBJECTIVE

This study explored the immunomodulatory and immunorestorative properties of a hot aqueous extract (APTR) and of a β-d-glucan-enriched polysaccharide fraction (BGP) of a local oyster mushroom Pleurutus tuberregium (Fr.) Singer (Pleurotaceae).

MATERIALS AND METHODS

Immunomodulatory activities were investigated by assessing specific and none-specific immune responses in immunocompetent and immunosuppressed mice; as well as in vitro in culture of RAW264.7 macrophages stimulated with BGP.

RESULTS

In a homologous prime-boost immunization schedule, oral supplementation with APTR (100, 200, or 400 mg/kg) and BGP (100 or 200 mg/kg) resulted in significantly higher titers of total IgG, IgG1, and IgG2a by as much as 2-4-folds compared with the levels in untreated control mice. The mean hemagglutination (HA) titer in immunized mice that were treated with dexamethasone (DEX; 5 mg/kg) was significantly (p < 0.05) lower than the titer in groups that did not receive dexamethasone; however, short-term alternate day administration of APTR (200 mg/kg) to mice that had been immunosuppressed with 5 mg DEX/kg produced significant increases in secondary anti-SRBC antibody compared with the mean titer of mice immunized and treated with DEX alone. In in vitro studies, stimulation of RAW264.7 macrophages with BGP caused significant increases in iNO and TNF-α expression, and phagocytic functions of the cell.

CONCLUSION

Taken together, the results of these studies showed that P. tuberregium imparts immunostimulatory and immunorestorative effects that could be explained, in part, by the actions of its β-d-glucan constituent(s) on macrophages.

Microemboli alter the acute stress response and cause prolonged expression of MCP-1 in the hippocampus

Microvascular ischemia is linked to cardiovascular disease pathology, as well as alterations in mood and cognition. Ischemia activates the hypothalamic-pituitary-adrenal (HPA) axis and through chronic activation, alters HPA axis function. Dysregulation of the HPA axis can lead to the chronic release of glucocorticoids, a hyper-inflammatory cerebral response, cell damage, and changes in behavior. Although the interactions between injury and HPA axis activity have been established in global ischemia, HPA-related repercussions of diffuse ischemic damage and subsequent inflammation have not been assessed. The current study used a rat model of microsphere embolism (ME) ischemia to test the hypothesis that microvascular ischemia would lead to long term alterations in HPA axis function and inflammatory activity. Furthermore, given the pro-inflammatory nature of chronic stress, we assessed the implications of chronic stress for gene expression of inflammatory factors and key components of the glucocorticoid receptor response, following microvascular ischemia. Results indicated that ME altered the response to an acute stress fourteen days following ME injury and increased hippocampal expression of monocyte chemoattractant protein 1 (Mcp-1) as long as 4 weeks following ME injury, without concomitant effects on gene expression of the glucocorticoid receptor or its co-chaperones. Furthermore, no exacerbative effects of chronic stress exposure were observed following ME injury beyond the effects of ME injury alone. Together, these results indicate that ME injury is sufficient to alter both HPA axis activity and cerebral inflammation for a prolonged period of time following injury.

Targeting glucocorticoid side effects: selective glucocorticoid receptor modulator or glucocorticoid-induced leucine zipper? A perspective

Glucocorticoids (GCs) are steroid hormones that are necessary for life and important in health and disease. They regulate crucial homeostatic functions, including metabolism, cell growth, and development. Although GCs are regulated by circadian rhythm, increased production is associated with stress. Synthetic GCs are a valuable resource for anti-inflammatory and immunosuppressive therapy. Natural and synthetic GCs transduce signals mainly through GC receptor (GR) activation. Extensive research has explored the downstream targets of the GR, and optimization of GC therapy has required collaborative efforts. One highly promising approach involves new dissociative GR modulators. Because transrepression and transactivation of GR genes induce beneficial and adverse effects, respectively, this approach favors transrepression. Another approach involves the use of GC-dependent genes to generate proteins to mediate therapeutic GC effects. In a third approach, drug discovery is used to identify agents that selectively target GR isoforms to obtain differential gene transcription and effects. In this review, we focus on mechanisms of GR function compatible with the use of dissociative drugs. We highlight GC-induced leucine zipper (GILZ), a gene cloned in our laboratory, as a mediator of GC anti-inflammatory and immunosuppressive effects, to outline our perspective on the future of GC therapy.

Effect of progestins on immunity: medroxyprogesterone but not norethisterone or levonorgestrel suppresses the function of T cells and pDCs

OBJECTIVES

The potential effect of hormonal contraception on HIV-1 acquisition and transmission represents an important public health issue. Several observational studies have suggested an association between the use of hormonal contraception, in particular injectable depot medroxyprogesterone acetate (DMPA), and an increased risk of HIV-1 acquisition and transmission. We and others have previously demonstrated that DMPA acts as a potent inhibitor of innate and adaptive immune mechanisms. The study presented here addresses the immunomodulatory properties of several common progestins with a potential to replace DMPA.

STUDY DESIGN

To identify safe alternatives to DMPA, we tested the effect of commonly used progestins on the function of human primary T cells and plasmacytoid dendritic cells (pDCs) obtained from the blood of healthy premenopausal women.

RESULTS

Medroxyprogesterone acetate (MPA) inhibited the activation of T cells and pDCs in response to T cell receptor- and Toll-like receptor-mediated activation at physiological concentrations. Etonogestrel exerted a partial suppressive activity at high concentrations. In sharp contrast, norethisterone (NET) and levonorgestrel (LNG) did not exhibit detectable immunosuppressive activity.

CONCLUSION

Evidence indicating the immunosuppressive properties of DMPA strongly suggests that DMPA should be discontinued and replaced with other forms of long-term contraception. Since NET and LNG do not exert immunosuppressive properties at physiological concentrations, these progestins should be considered as alternative contraceptives for women at high risk for HIV-1 infection.

IMPLICATIONS

The presented data suggest that, at physiological levels, the progestins NET and LNG do not suppress cytokine production by immune cells and should be considered as alternatives to DMPA; however, more in vivo testing is needed to confirm this data.

Calorie restriction dose-dependently abates lipopolysaccharide-induced fever, sickness behavior, and circulating interleukin-6 while increasing corticosterone

In mice a 50% calorie restriction (CR) for 28days attenuates sickness behavior after lipopolysaccharide (LPS) and these mice demonstrate a central anti-inflammatory bias. This study examined the dose-dependent effect of CR on sickness behavior (fever, anorexia, cachexia) and peripheral immune markers post-LPS. Male Sprague-Dawley rats fed ad libitum or CR by 50% for 14, 21, or 28days were injected on day 15, 22, or 29 with 50μg/kg of LPS or saline (1mL/500g). Changes in body temperature (Tb), locomotor activity, body weight, and food intake were determined. A separate cohort of rats was fed ad libitum or CR by 50% for 28days and serum levels of corticosterone (CORT), interleukin 6 (IL-6), and IL-10 were determined at 0, 2, and 4h post-LPS. The rats CR for 28days demonstrated the largest attenuation of sickness behavior: no fever, limited reduction in locomotor activity, no anorexia, and reduced cachexia following LPS. Rats CR for 14 and 21days demonstrated a partial attenuation of sickness behavior. Rats CR for 14days demonstrated a larger increase in Tb, larger reduction in locomotor activity, and larger weight loss compared to rats CR for 21days. Serum CORT was increased at 2h post-LPS in ad libitum and CR groups; however it was two times larger in the CR animals. Levels of IL-6 were significantly attenuated at 2h post-LPS in the CR animals. IL-10 levels were similar post-LPS. CR results in an enhanced anti-inflammatory response in the form of increased CORT and diminished pro-inflammatory signals.

Identification of a selective glucocorticoid receptor ligand for the treatment of chronic inflammation in type 2 diabetes mellitus

The present study aimed to identify a new selective glucocorticoid receptor (GR) ligand for the treatment of chronic inflammation in type 2 diabetes mellitus. The IN Cell Analyzer 1000 platform was employed to screen for compounds that may promote GR nuclear translocation. A mammalian two-hybrid system and transactivation assay-were used to analyze the selected GR ligands and evaluate their activities for GR transcription and the recruitment of co-activators. A novel selective GR ligand, compound Q40, was identified that was able to promote GR nuclear translocation in a short period of time. It increased the ability of GR to recruit co-activators in a concentration-dependent manner, but had no positive effect on GR transcriptional activity. In conclusion, an increase in the expression levels of gluconeogeneic genes, induced by the transcriptional activation of GR, is the predisposing factor most commonly associated with the side-effects of glucocorticoids. The results suggest that compound Q40 is a ligand of the GR and exerts an agonistic action on the recruitment of co-activators without sugar dysmetabolism-related side-effects. Thus, compound Q40 has the potential to be used as an anti-inflammatory adjuvant therapy with minimal side-effects in patients with type 2 diabetes mellitus.

Effects of representative glucocorticoids on TNFα- and CD40L-induced NF-κB activation in sensor cells

Glucocorticoids are an important class of anti-inflammatory/immunosuppressive drugs. A crucial part of their anti-inflammatory action results from their ability to repress proinflammatory transcription factors such as nuclear factor-κB (NF-κB) and activator protein-1 (AP-1) upon binding to the glucocorticoid receptor (GR). Accordingly, sensor cells quantifying their effect on inflammatory signal-induced NF-κB activation can provide useful information regarding their potencies as well as their transrepression abilities. Here, we report results obtained on their effect in suppressing both the TNFα- and the CD40L-induced activation of NF-κB in sensor cells that contain an NF-κB-inducible SEAP construct. In these cells, we confirmed concentration-dependent NF-κB activation for both TNFα and CD40L at low nanomolar concentrations (EC50). Glucocorticoids tested included hydrocortisone, prednisolone, dexamethasone, loteprednol etabonate, triamcinolone acetonide, beclomethasone dipropionate, and clobetasol propionate. They all caused significant, but only partial inhibition of these activations in concentration-dependent manners that could be well described by sigmoid response-functions. Despite the limitations of only partial maximum inhibitions, this cell-based assay could be used to quantitate the suppressing ability of glucocorticoids (transrepression potency) on the expression of proinflammatory transcription factors caused by two different cytokines in parallel both in a detailed, full dose-response format as well as in a simpler single-dose format. Whereas inhibitory potencies obtained in the TNF assay correlated well with consensus glucocorticoid potencies (receptor-binding affinities, Kd, RBA, at the GR) for all compounds, the non-halogenated steroids (hydrocortisone, prednisolone, and loteprednol etabonate) were about an order of magnitude more potent than expected in the CD40 assay in this system.

Electrophilic lipid mediator 15-deoxy-Δ12,14-prostaglandin j2 modifies glucocorticoid signaling via receptor SUMOylation

Cortisol, the central stress hormone in humans, activates the glucocorticoid receptor (GR). Anti-inflammatory effects are the most important pharmaceutical effects mediated by the GR. Inasmuch as electrophilic cyclopentenone prostaglandin 15-deoxy-Δ(12,14)-prostaglandin J2 (15d-PGJ2) has potent anti-inflammatory properties and activates the SUMOylation pathway, we have investigated the effect of 15d-PGJ2 on glucocorticoid signaling and receptor SUMOylation. To this end, we studied isogenic HEK293 cells expressing either wild-type GR or SUMOylation-defective GR. Interestingly, 15d-PGJ2 triggered SUMO-2 and -3 (SUMO-2/3) modification in the primary SUMOylation sites of the GR. Gene expression profiling and pathway analyses indicate that 15d-PGJ2 inhibits GR signaling in a genome-wide fashion that is significantly dependent on the GR SUMOylation sites. Chromatin immunoprecipitation assays showed that the repressive effect of 15d-PGJ2 on GR target gene expression occurs in parallel with the inhibition of receptor binding to the target gene chromatin. Furthermore, depletion of UBC9, the sole SUMO E2 conjugase, from HEK293 cells confirmed the involvement of active SUMOylation in the regulatory process. Taken together, our data indicate that GR SUMOylation modulates the glucocorticoid signaling during acute cell stress. Our data also suggest that GR SUMOylation modulates cross talk of the glucocorticoid signaling with other transcription factors that are responsive to cell stress.

Epigenetic influences on associations between air pollutants and lung function in elderly men: the normative aging study

BACKGROUND

Few studies have been performed on pulmonary effects of air pollution in the elderly--a vulnerable population with low reserve capacity--and mechanisms and susceptibility factors for potential effects are unclear.

OBJECTIVES

We evaluated the lag structure of air pollutant associations with lung function and potential effect modification by DNA methylation (< or ≥ median) at 26 individual CpG sites in nine candidate genes in a well-characterized cohort of elderly men.

METHODS

We measured forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV1), and blood DNA methylation one to four times between 1999 and 2009 in 776 men from the Normative Aging Study. Air pollution was measured at fixed monitors 4 hr to 28 days before lung function tests. We used linear mixed-effects models to estimate the main effects of air pollutants and effect modification by DNA methylation.

RESULTS

An interquartile range (IQR) increase in subchronic exposure (3 to 28 days cumulated), but not in acute exposure (during the previous 4 hr, or the current or previous day), to black carbon, total and nontraffic particles with aerodynamic diameter ≤ 2.5 μm (PM2.5), carbon monoxide, and nitrogen dioxide was associated with a 1-5% decrease in FVC and FEV1 (p < 0.05). Slope estimates were greater for FVC than FEV1, and increased with cumulative exposure. The estimates slopes for air pollutants (28 days cumulated) were higher in participants with low (< median) methylation in TLR2 at position 2 and position 5 and high (≥ median) methylation in GCR.

CONCLUSIONS

Subchronic exposure to traffic-related pollutants was associated with significantly reduced lung function in the elderly; nontraffic pollutants (particles, ozone) had weaker associations. Epigenetic mechanisms related to inflammation and immunity may influence these associations.

Liposomal corticosteroids for the treatment of inflammatory disorders and cancer

Glucocorticoids (GC) are known for their potent immunosuppressive and anti-inflammatory properties. As a consequence, they have been extensively used for the treatment of many different diseases. Prolonged and/or high-dose GC therapy, however, generally comes with severe side effects, resulting not only from their very diverse mechanism(s) of action, but also from their relatively poor biodistribution. Drug delivery systems, and in particular liposomes, have been extensively used to enhance the biodistribution and the target site accumulation of GC, and to thereby improve the balance between their efficacy and their toxicity. Many different types of liposomes have been employed, and both local and systemic treatments have been evaluated. We here summarize the progress made in the use of liposomal GC formulations for the treatment of asthma, rheumatoid arthritis, multiple sclerosis and cancer, and we show that the targeted delivery of GC to pathological sites holds significant clinical potential.

Dexamethasone Induces Apoptosis of Nasal Polyp-Derived Tissue Cultures Through JNK and p38 MAPK Activation

Objectives

Glucocorticoids, such as dexamethasone (DEX), increase apoptosis in a variety of white cells in nasal polyps and apoptosis is an important factor in the resolution of inflammation. However, the mechanism of glucocorticoids induced apoptosis in nasal polyp remains unclear. In this study the authors evaluated which pathways were engaged in apoptosis induced by DEX in an ex vivo model of nasal polyps.

Methods

Nasal polyp tissues were cultured using an air-liquid interface method. Cultures were maintained in the absence or presence of DEX (10 or 100 µM) for 24 hours. To investigate the involvement of the apoptotic signaling pathways in nasal polyp, such as caspase cascades, Fas-FasL signaling pathway, mitochondrial pathway and p38 mitogen-activated protein kinase (MAPK)/JNK pathway, the authors performed reverse transcription-polymerase chain reaction and Western blotting.

Results

The expression ratios of FasL, activated form of caspase-8, caspase-9, and caspase-3 were significantly higher in DEX-treated polyps (P<0.01). In the Bcl-2 family expression, the anti-apoptotic molecules, Bcl-2 and Bcl-XL decreased, but pro-apoptotic molecules, Bax increased, and Bid and Bad were activated. In the conventional MAPKs, JNK, and the phospho-p38 MAPK were significantly higher, but phospho-extracellular signal-regulated kinase (ERK)1/2 was significantly lower in DEX-treated polyps (P<0.01).

Conclusion

DEX induces apoptosis of nasal polyp via caspase cascades, Fas-FasL signaling pathway, mitochondrial pathway and p38 MAPK/JNK pathway.

Bortezomib induces apoptosis by interacting with JAK/STAT pathway in K562 leukemic cells

In the current study, we aimed to identify the cytotoxic and apoptotic effects of bortezomib (BOR) on human K562 chronic myelogenous leukemia cells and to evaluate the potential roles of Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway members STAT3, STAT5, and JAK2 on BOR-induced cell death of leukemic cells. Cell viability was assessed via trypan blue dye exclusion test, and cytotoxicity of the BOR-treated cells was conducted by 2,3-bis(2-methoxy-4-nitro-5-sulphophenyl)-2H-tetrazolium-5-carboxanilide inner salt (XTT) assay. The relative messenger RNA (mRNA) expression levels of STAT3, STAT5A, STAT5B, and JAK2 were analyzed by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). On the other hand, their protein expression levels were detected by western blot method. The obtained results indicated that BOR treatment reduced cell viability and induced leukemic cell apoptosis in a dose- and time-dependent manner as compared to untreated control cells. While mRNA expression levels of STAT5A, STAT5B, and STAT3 were significantly reduced following BOR treatment when compared to untreated controls, it had no effect upon JAK2 mRNA expression. As for protein levels, STAT expressions were downregulated after BOR treatment especially at 72nd and 96th hours. Our results pointed out that BOR treatment had a significant potential of being an anticancer agent for chronic myelogenous leukemia therapy, and this effect could be due to the expressional downregulations of JAK/STAT pathway members.

Maternal high-fat diet alters anxiety behavior and glucocorticoid signaling in adolescent offspring

Maternal obesity and overconsumption of saturated fats during pregnancy have profound effects on offspring health, ranging from metabolic to behavioral disorders in later life. The influence of high-fat diet (HFD) exposure on the development of brain regions implicated in anxiety behavior is not well understood. We previously found that maternal HFD exposure is associated with an increase in anxiety behavior and alterations in the expression of several genes involved in inflammation via the glucocorticoid signaling pathway in adult rat offspring. During adolescence, the maturation of feedback systems mediating corticosteroid sensitivity is incomplete, and therefore distinct from adulthood. In this study, we examined the influence of maternal HFD on several measures of anxiety behavior and gene expression in adolescent offspring. We examined the expression of corticosteroid receptors and related inflammatory processes, as corticosteroid receptors are known to regulate circulating corticosterone levels during basal and stress conditions in addition to influencing inflammatory processes in the hippocampus and amygdala. We found that adolescent animals perinatally exposed to HFD generally showed decreased anxiety behavior accompanied by a selective alteration in the expression of the glucocorticoid receptor and several downstream inflammatory genes in the hippocampus and amygdala. These data suggest that adolescence constitutes an additional period when the effects of developmental programming may modify mental health trajectories.