Rapid nongenomic inhibitory effects of glucocorticoids on phagocytosis and superoxide anion production by macrophages

Diabetes-associated neutrophil NETosis: pathogenesis and interventional target of diabetic complications

Neutrophil extracellular traps (NETs) are known as extracellular fibers networks consisting of antimicrobial proteins and decondensated chromatin DNA released by activated neutrophils. NETosis is a NETs-induced neutrophilic cell death which is unique from necrosis or apoptosis. Besides its neutralizing pathogen, NETosis plays a crucial role in diabetes and diabetes-related complications. In patients with diabetes, NETs-releasing products are significantly elevated in blood, and these findings confirm the association of NETosis and diabetic complications, including diabetic wound healing, diabetic retinopathy, and atherosclerosis. This article briefly summarizes the mechanisms of NETosis and discusses its contribution to the pathogenesis of diabetes-related complications and suggests new therapeutic targets by some small molecule compounds.

New pro-inflammatory cytokine IL-40 is produced by activated neutrophils and plays a role in the early stages of seropositive rheumatoid arthritis

OBJECTIVE

Interleukin (IL)-40 is a new cytokine related to immune system function and malignancies. Recently, an association of IL-40 with rheumatoid arthritis (RA) and externalisation of neutrophil extracellular traps (NETosis) was found. As neutrophils are implicated in RA development, we investigated IL-40 in early stages of RA (ERA).

METHODS

IL-40 was determined in serum of treatment naïve patients with ERA at baseline (n=60) and 3 months after initiation of conventional therapy and in healthy controls (HC; n=60). Levels of IL-40, cytokines and NETosis markers were measured by ELISA. NETosis was visualised by immunofluorescence. In vitro experiments were performed on peripheral blood neutrophils from ERA patients (n=14). Cell-free DNA was analysed in serum and supernatants.

RESULTS

Serum IL-40 was elevated in ERA compared with HC (p<0.0001) and normalised after 3 months of therapy (p<0.0001). Baseline serum IL-40 correlated with rheumatoid factor (IgM) (p<0.01), anti-cyclic citrullinated peptide (p<0.01) autoantibodies and NETosis markers (proteinase 3; neutrophil elastase (NE); myeloperoxidase) (p<0.0001). Levels of NE significantly decreased after therapy (p<0.01) and correlated with the decrease of serum IL-40 (p<0.05). In vitro, neutrophils enhanced IL-40 secretion following NETosis induction (p<0.001) or after exposure to IL-1β, IL-8 (p<0.05), tumour necrosis factor or lipopolysaccharide (p<0.01). Recombinant IL-40 up-regulated IL-1β, IL-6 and IL-8 (p<0.05 for all) in vitro.

CONCLUSION

We showed that IL-40 is significantly up-regulated in seropositive ERA and decreases after conventional therapy. Moreover, neutrophils are an important source of IL-40 in RA, and its release is potentiated by cytokines and NETosis. Thus, IL-40 may play a role in ERA.

Macrophages Rapidly Seal off the Punctured Zebrafish Larval Brain through a Vital Honeycomb Network Structure

There is accumulating evidence that macrophages play additional important roles in tissue damage besides their typical phagocytosis. Although the aggregation of macrophages on injured sites has long been observed, few researchers have focused on the role of the overall structure of macrophage aggregation. In this study, we developed a standardized traumatic brain injury (TBI) model in zebrafish larvae to mimic edema and brain tissue spillage symptoms after severe brain trauma. Using time-lapse imaging, we showed that macrophages/microglia in zebrafish larvae responded rapidly and dominated the surface of injured tissue, forming a meaningful honeycomb network structure through their compact aggregation and connection. Disrupting this structure led to fatal edema-like symptoms with severe loss of brain tissue. Using the RNA-Seq, together with the manipulation of in vitro cell lines, we found that collagen IV was indispensable to the formation of honeycomb network structures. Our study thus revealed a novel perspective regarding macrophages forming a protective compact structure with collagen IV. This honeycomb network structure acted as a physical barrier to prevent tissue loss and maintain brain homeostasis after TBI. This study may provide new evidence of macrophages’ function for the rapid protection of brain tissue after brain injury.

Inhibition of NETosis for treatment purposes: friend or foe?

Active neutrophils participate in innate and adaptive immune responses through various mechanisms, one of the most important of which is the formation and release of neutrophil extracellular traps (NETs). The NETs are composed of network-like structures made of histone proteins, DNA and other released antibacterial proteins by activated neutrophils, and evidence suggests that in addition to the innate defense against infections, NETosis plays an important role in the pathogenesis of several other non-infectious pathological states, such as autoimmune diseases and even cancer. Therefore, targeting NET has become one of the important therapeutic approaches and has been considered by researchers. NET inhibitors or other molecules involved in the NET formation, such as the protein arginine deiminase 4 (PAD4) enzyme, an arginine-to-citrulline converter, participate in chromatin condensation and NET formation, is the basis of this therapeutic approach. The important point is whether complete inhibition of NETosis can be helpful because by inhibiting this mechanism, the activity of neutrophils is suppressed. In this review, the biology of NETosis and its role in the pathogenesis of some important diseases have been summarized, and the consequences of treatment based on inhibition of NET formation have been discussed.

A Novel Polysaccharide Isolated From Fresh Longan (Dimocarpus longan Lour.) Activates Macrophage via TLR2/4-Mediated PI3/AKT and MyD88/TRAF6 Pathways

A novel immunomodulatory polysaccharide (LP4) with a molecular weight 6.31 × 10⁴ g/mol was purified from fresh longan pulp. It was composed of mannose, glucose, glucuronic acid, galactose, xylose, arabinose, galacturonic acid, fucose, and rhamnose in a molar percentage of 36:31:10:7:4:4:3:2:2, and mainly linked by (1→6)-β-Man, (1→4)-β-Glc and (1→6)-α-Glc. LP4 can obviously enhance the phagocytosis of macrophages and promote the proliferation of lymphocytes. After treating macrophages with LP4 (12.5–50 μg/ml), the production of IL-1β and TNF-α was significantly increased. These increases of cytokines were suppressed when the TLR2/TLR4 receptors were inhibited by anti-TLR2 and/or anti-TLR4 antibodies. Moreover, the mRNA expression of INOS, AKT, PI3K, TRAF6 and MyD88 was significantly suppressed by TLR2/TLR4 antibodies. These results indicated that LP4 induced macrophage activation mainly via the TLR2 and TLR4-induced PI3K/AKT and MyD88/TRAF6 pathways.

Psychologically Traumatic Oxidative Stress; A Comprehensive Review of Redox Mechanisms and Related Inflammatory Implications

The organism's energy requirements for homeostatic balance are covered by the redox mechanisms. Yet in case of psychologically traumatic stress, allostatic regulations activate both pro-oxidant and antioxidant molecules as well as respective components of the inflammatory system. Thus a new setpoint of dynamic interactions among redox elements is reached. Similarly, a multifaceted interplay between redox and inflammatory fields is activated with the mediation of major effector systems such as the immune system, Hypothalamic-Pituitary-Adrenal axis, kynurenine, and the glycaemic regulatory one. In case of sustained and/or intense traumatic stress the prophylactic antioxidant components are inadequate to provide the organism with neuroprotection finally culminating in Oxidative Stress and subsequently to cellular apoptosis. In parallel multiple inflammatory systems trigger and/or are triggered by the redox systems in tight fashion so that the causation sequence appears obscure. This exhaustive review aims at the comprehension of the interaction among components of the redox system as well as to the collection of disperse findings relative to the redox-inflammatory interplay in the context of traumatic stress so that new research strategies could be developed.

Effects of cadmium on antioxidant and non-specific immunity of Macrobrachium nipponense

As a non-essential and toxic element, cadmium poses an important threat to aquatic organisms and human food safety. In this study, the effects of cadmium on antioxidant and non-specific immunity of Macrobrachium nipponense were studied from the physiological and biochemical indexes, histology and expression of related genes. These results showed that low concentrations (0.01, 0.02 mg/L) of cadmium have a positive effect on the non-specific immunity of M. nipponense, but high concentration (0.04 mg/L) of cadmium could inhibit or even damage the non-specific immunity of M. nipponense. The cadmium could induce oxidative stress in M. nipponense, and M. nipponense actived the antioxidant defense system to deal with oxidative stress, but high concentration (0.04 mg/L) of cadmium could inhibit the antioxidant defense system of M. nipponense, leading to oxidative damage, and may induce apoptosis in severe case. At the same time, the results of histology showed that cadmium can damage the structure of gill and hepatopancreas tissues of M. nipponense. This study provides theoretical data for evaluating the influences of heavy metal cadmium on M. nipponense and the toxic mechanism of heavy metal cadmium.

A guide to changing paradigms of glucocorticoid receptor function-a model system for genome regulation and physiology

The glucocorticoid receptor (GR) is a bona fide ligand-regulated transcription factor. Cloned in the 80s, the GR has become one of the best-studied and clinically most relevant members of the nuclear receptor superfamily. Cooperative activity of GR with other transcription factors and a plethora of coregulators contribute to the tissue- and context-specific response toward the endogenous and pharmacological glucocorticoids (GCs). Furthermore, nontranscriptional activities in the cytoplasm are emerging as an additional function of GR. Over the past 40 years, the concepts of GR mechanisms of action had been constantly changing. Different methodologies in the pregenomic and genomic era of molecular biological research and recent cutting-edge technology in single-cell and single-molecule analysis are steadily evolving the views, how the GR in particular and transcriptional regulation in general act in physiological and pathological processes. In addition to the development of technologies for GR analysis, the use of model organisms provides insights how the GR in vivo executes GC action in tissue homeostasis, inflammation, and energy metabolism. The model organisms, namely the mouse, but also rats, zebrafish, and recently fruit flies carrying mutations of the GR became a major driving force to analyze the molecular function of GR in disease models. This guide provides an overview of the exciting research and paradigm shifts in the GR field from past to present with a focus on GR transcription factor networks, GR DNA-binding and single-cell analysis, and model systems.

Oxidative Dysregulation in Early Life Stress and Posttraumatic Stress Disorder: A Comprehensive Review

Traumatic stress may chronically affect master homeostatic systems at the crossroads of peripheral and central susceptibility pathways and lead to the biological embedment of trauma-related allostatic trajectories through neurobiological alterations even decades later. Lately, there has been an exponential knowledge growth concerning the effect of traumatic stress on oxidative components and redox-state homeostasis. This extensive review encompasses a detailed description of the oxidative cascade components along with their physiological and pathophysiological functions and a systematic presentation of both preclinical and clinical, genetic and epigenetic human findings on trauma-related oxidative stress (OXS), followed by a substantial synthesis of the involved oxidative cascades into specific and functional, trauma-related pathways. The bulk of the evidence suggests an imbalance of pro-/anti-oxidative mechanisms under conditions of traumatic stress, respectively leading to a systemic oxidative dysregulation accompanied by toxic oxidation byproducts. Yet, there is substantial heterogeneity in findings probably relative to confounding, trauma-related parameters, as well as to the equivocal directionality of not only the involved oxidative mechanisms but other homeostatic ones. Accordingly, we also discuss the trauma-related OXS findings within the broader spectrum of systemic interactions with other major influencing systems, such as inflammation, the hypothalamic-pituitary-adrenal axis, and the circadian system. We intend to demonstrate the inherent complexity of all the systems involved, but also put forth associated caveats in the implementation and interpretation of OXS findings in trauma-related research and promote their comprehension within a broader context.

General Adaptation in Critical Illness: Glucocorticoid Receptor-alpha Master Regulator of Homeostatic Corrections

In critical illness, homeostatic corrections representing the culmination of hundreds of millions of years of evolution, are modulated by the activated glucocorticoid receptor alpha (GRα) and are associated with an enormous bioenergetic and metabolic cost. Appreciation of how homeostatic corrections work and how they evolved provides a conceptual framework to understand the complex pathobiology of critical illness. Emerging literature place the activated GRα at the center of all phases of disease development and resolution, including activation and re-enforcement of innate immunity, downregulation of pro-inflammatory transcription factors, and restoration of anatomy and function. By the time critically ill patients necessitate vital organ support for survival, they have reached near exhaustion or exhaustion of neuroendocrine homeostatic compensation, cell bio-energetic and adaptation functions, and reserves of vital micronutrients. We review how critical illness-related corticosteroid insufficiency, mitochondrial dysfunction/damage, and hypovitaminosis collectively interact to accelerate an anti-homeostatic active process of natural selection. Importantly, the allostatic overload imposed by these homeostatic corrections impacts negatively on both acute and long-term morbidity and mortality. Since the bioenergetic and metabolic reserves to support homeostatic corrections are time-limited, early interventions should be directed at increasing GRα and mitochondria number and function. Present understanding of the activated GC-GRα's role in immunomodulation and disease resolution should be taken into account when re-evaluating how to administer glucocorticoid treatment and co-interventions to improve cellular responsiveness. The activated GRα interdependence with functional mitochondria and three vitamin reserves (B1, C, and D) provides a rationale for co-interventions that include prolonged glucocorticoid treatment in association with rapid correction of hypovitaminosis.

Human cytomegalovirus IE2 protein regulates macrophage-mediated immune escape by upregulating GRB2 expression in UL122 genetically modified mice

Although cytomegalovirus (HCMV) infection is asymptomatic in healthy individuals, the virus can remain latent for many years due to its ability to evade host immune surveillance. However, reactivation of HCMV can lead to life-threatening disease. Recent studies have shown that HCMV infection mediates immune escape by regulating macrophage activity, although the role of the HCMV-encoded IE2 protein is unclear. A ul122 transgenic mouse model was created to stably expresses the IE2 protein, and the proportion of M1 and M2 macrophage populations in their spleen and bone marrow was compared to that in wild-type controls. In addition, the phagocytic function of the macrophages was evaluated in terms of neutral red dye uptake. Spleen and bone marrow macrophages in IE2-expressing mice were mainly of the M2 phenotype and displayed enhanced phagocytic function compared to that in control mice. The relative levels of expression of macrophage-related GRB2 and of IL-4, IFN-γ, IL-13, and TNF-α were also analyzed in the spleen and bone marrow of the two groups. The IE2-expressing mice had increased expression of GRB2 and increased expression of the M2-related cytokines IL-4 and IL-13. Taken together, the current results suggest that HCMV IE2 polarizes the host macrophages to the M2 type via a GRB2/IL-4-related pathway, which enables long-term survival of the virus in the host.

The impact of preterm adversity on cardiorespiratory function

NEW FINDINGS

What is the topic of this review? We review the influence of prematurity on the cardiorespiratory system and examine the common sequel of alterations in oxygen tension, and immune activation in preterm infants. What advances does it highlight? The review highlights neonatal animal models of intermittent hypoxia, hyperoxia and infection that contribute to our understanding of the effect of stress on neurodevelopment and cardiorespiratory homeostasis. We also focus on some of the important physiological pathways that have a modulatory role on the cardiorespiratory system in early life.

ABSTRACT

Preterm birth is one of the leading causes of neonatal mortality. Babies that survive early-life stress associated with immaturity have significant prevailing short- and long-term morbidities. Oxygen dysregulation in the first few days and weeks after birth is a primary concern as the cardiorespiratory system slowly adjusts to extrauterine life. Infants exposed to rapid alterations in oxygen tension, including exposures to hypoxia and hyperoxia, have altered redox balance and active immune signalling, leading to altered stress responses that impinge on neurodevelopment and cardiorespiratory homeostasis. In this review, we explore the clinical challenges posed by preterm birth, followed by an examination of the literature on animal models of oxygen dysregulation and immune activation in the context of early-life stress.

More Than Suppression: Glucocorticoid Action on Monocytes and Macrophages

Uncontrolled inflammation is a leading cause of many clinically relevant diseases. Current therapeutic strategies focus mainly on immunosuppression rather than on the mechanisms of inflammatory resolution. Glucocorticoids (GCs) are still the most widely used anti-inflammatory drugs. GCs affect most immune cells but there is growing evidence for cell type specific mechanisms. Different subtypes of monocytes and macrophages play a pivotal role both in generation as well as resolution of inflammation. Activation of these cells by microbial products or endogenous danger signals results in production of pro-inflammatory mediators and initiation of an inflammatory response. GCs efficiently inhibit these processes by down-regulating pro-inflammatory mediators from macrophages and monocytes. On the other hand, GCs act on “naïve” monocytes and macrophages and induce anti-inflammatory mediators and differentiation of anti-inflammatory phenotypes. GC-induced anti-inflammatory monocytes have an increased ability to migrate toward inflammatory stimuli. They remove endo- and exogenous danger signals by an increased phagocytic capacity, produce anti-inflammatory mediators and limit T-cell activation. Thus, GCs limit amplification of inflammation by repressing pro-inflammatory macrophage activation and additionally induce anti-inflammatory monocyte and macrophage populations actively promoting resolution of inflammation. Further investigation of these mechanisms should lead to the development of novel therapeutic strategies to modulate undesirable inflammation with fewer side effects via induction of inflammatory resolution rather than non-specific immunosuppression.

Fighting the Fire: Mechanisms of Inflammatory Gene Regulation by the Glucocorticoid Receptor

For many decades, glucocorticoids have been widely used as the gold standard treatment for inflammatory conditions. Unfortunately, their clinical use is limited by severe adverse effects such as insulin resistance, cardiometabolic diseases, muscle and skin atrophies, osteoporosis, and depression. Glucocorticoids exert their effects by binding to the Glucocorticoid Receptor (GR), a ligand-activated transcription factor which both positively, and negatively regulates gene expression. Extensive research during the past several years has uncovered novel mechanisms by which the GR activates and represses its target genes. Genome-wide studies and mouse models have provided valuable insight into the molecular mechanisms of inflammatory gene regulation by GR. This review focusses on newly identified target genes and GR co-regulators that are important for its anti-inflammatory effects in innate immune cells, as well as mutations within the GR itself that shed light on its transcriptional activity. This research progress will hopefully serve as the basis for the development of safer immune suppressants with reduced side effect profiles.

Nongenomic glucocorticoid effects and their mechanisms of action in vertebrates

Glucocorticoids (GC) act on multiple organ systems to regulate a variety of physiological processes in vertebrates. Due to their immunosuppressive and anti-inflammatory actions, glucocorticoids are an attractive target for pharmaceutical development. Accordingly, they are one of the most widely prescribed classes of therapeutics. Through the classical mechanism of steroid action, glucocorticoids are thought to mainly affect gene transcription, both in a stimulatory and suppressive fashion, regulating de novo protein synthesis that subsequently leads to the physiological response. However, over the past three decades multiple lines of evidence demonstrate that glucocorticoids may work through rapid, nonclassical mechanisms that do not require alterations in gene transcription or translation. This review assimilates evidence across the vertebrate taxa on the diversity of nongenomic actions of glucocorticoids and the membrane-associated cellular mechanisms that may underlie rapid glucocorticoid responses to include potential binding sites characterized to date.

Cefquinome-Loaded Microsphere Formulations in Protection against Pneumonia with Klebsiella pneumonia Infection and Inflammatory Response in Rats

PURPOSE

This study aimed to compare in vivo activity between cefquinome (CEQ)-loaded poly lactic-co-glycolic acid (PLGA) microspheres (CEQ-PLGA-MS) and CEQ injection (CEQ-INJ) against Klebsiella pneumonia in a rat lung infection model.

METHODS

Forty-eight rats were divided into control group (sham operated without infection and drug treatment), Klebsiella pneumonia model group (KPD + Saline), CEQ-PLGA-MS and CEQ-INJ therapy groups (KPD + CEQ-PLGA-MS and KPD + INJ, respectively). In the KPD + Saline group, rats were infected with Klebsiella pneumonia ATCC 10031. In the KPD + CEQ-PLGA-MS and KPD + INJ groups, infected rats were intravenously injected with 12.5 mg/kg body weight CEQ-PLGA-MS and CEQ-INJ, respectively.

RESULTS

Compared to CEQ-INJ treatment group, CEQ-PLGA-MS treatment further decreased the number of bacteria colonies (decreased to 1.94 lg CFU/g) in lung tissues and the levels of inflammatory cytokine including tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-4 (p < 0.05 or p < 0.01) in bronchoalveolar lavage fluid at 48 h. Consistently, a significant decreases of scores of inflammation severity were showed at 48 h in the KPD + CEQ-PLGA-MS treatment group, compared to the KPD + CEQ-INJ treatment group.

CONCLUSION

Our results reveal that CEQ-PLGA-MS has the better therapeutic effect than CEQ-INJ for Klebsiella pneumonia lung infections in rats. The vehicle of CEQ-PLGA-MS as the promising alternatives to control the lung infections with the important pathogens.

Membrane-initiated nuclear trafficking of the glucocorticoid receptor in hypothalamic neurons

Glucocorticoid binding to the intracellular glucocorticoid receptor (GR) stimulates the translocation of the GR from the cytosol to the nucleus, which leads to the transactivation or transrepression of gene transcription. However, multiple lines of evidence suggest that glucocorticoid signaling can also be initiated from the plasma membrane. Here, we provide evidence for membrane-initiated glucocorticoid signaling by a membrane-impermeant dexamethasone-bovine serum albumin (Dex-BSA) conjugate, which induced GR nuclear trafficking in hypothalamic neurons in vitro and in vivo. The GR nuclear translocation induced by a membrane-impermeant glucocorticoid suggests trafficking of an unliganded GR. The membrane-initiated GR trafficking was not blocked by inhibiting ERK MAPK, p38 MAPK, PKA, Akt, Src kinase, or calcium signaling, but was inhibited by Akt activation. Short-term exposure of hypothalamic neurons to dexamethasone (Dex) activated the glucocorticoid response element (GRE), suggesting transcriptional transactivation, whereas exposure to the Dex-BSA conjugate failed to activate the GRE, suggesting differential transcriptional activity of the liganded compared to the unliganded GR. Microarray analysis revealed divergent transcriptional regulation by Dex-BSA compared to Dex. Together, our data suggest that signaling from a putative membrane glucocorticoid receptor induces the trafficking of unliganded GR to the nucleus, which elicits a pattern of gene transcription that differs from that of the liganded receptor. The differential transcriptional signaling by liganded and unliganded receptors may contribute to the broad range of genetic regulation by glucocorticoids, and may help explain some of the different off-target actions of glucocorticoid drugs.

Cefquinome-loaded microsphere formulations against Klebsiella pneumonia infection during experimental infections

The aim of this study was to prepare cefquinome-loaded polylactic acid microspheres and to evaluate their in vitro and in vivo characteristics and pharmacodynamics for the therapy of pneumonia in a rat model. Microspheres were prepared using a 0.7 mm two-fluid nozzle spray drier in one step resulting in spherical and smooth microspheres of uniform size (9.8 ± 3.6 μm). The encapsulation efficiency and drug loading of cefquinome were 91.6 ± 2.6% and 18.7 ± 1.2%, respectively. In vitro release of cefquinome from the microspheres was sustained for 36 h. Cefquinome-loaded polylactic acid microspheres as a drug delivery system was successful for clearing experimental Klebsiella pneumonia lung infections. A decrease in inflammatory cells and an inhibition of inflammatory cytokines TNF-α, IL-1β and IL-8 after microspheres treatment was found. Changes in cytokine levels and types are secondary manifestations of drug bactericidal effects. Rats were considered to be microbiologically cured because the bacterial load was less than 100 CFU/g. These results also indicated that the spray-drying method of loading therapeutic drug into polylactic acid microspheres is a straightforward and safe method for lung-targeting therapy in animals.

Immunosuppressive potential of astemizole against LPS activated T cell proliferation and cytokine secretion in RAW macrophages, zebrafish larvae and mouse splenocytes by modulating MAPK signaling pathway

In this study, the immunomodulatory effects of astemizole (AST) against lipopolysaccharide (LPS) mediated T cell proliferation and induction of inflammation in RAW macrophages (in vitro), and zebrafish larvae (in vivo) were determined. AST significantly suppressed the phagocytic activity of macrophages (3.303 ± 0.115) and inhibited lysosomal enzyme secretion (13.27 ± 2.52) induced by LPS (100 ng/ml). Moreover, AST subdued the morphological deformities such as yolk sac edema (YSE) and spinal curvature curving (SC) by inhibiting ROS generation in zebrafish larvae 24 h after microinjection of LPS (0.5 mg/ml). AST was also shown to inhibit the production of the major cytokines TNF-α (150.8 ± 0.6), IL-1β (276.5 ± 1.6), and PGE₂ (194.6 ± 0.6) pg/ml in RAW macrophages. It also subdued the ROS induced iNOS and COX-2 generated in response to LPS mediated immune dysfunctions in zebrafish larvae. These results suggested the immunosuppression effect of AST. Furthermore, induction of immune-suppression due to AST resulted in significant down-regulation of innate immunity directed by MAPK (p38, ERK and JNK), which was found to be associated with decreased production of acute inflammatory mediators both in vitro and in vivo. To confirm its activity, splenocytes were prepared using BALB/c mice and a mitogen activated splenocyte proliferation assay was also performed. Our findings suggest that AST has the ability to inhibit T cell proliferation and cytokine secretion both in vitro and in vivo by interfering with MAPK signaling pathway. Taken together, our results showed the potential of AST as a countermeasure to immune dysfunction and suggest its use as immunosuppressant compound in inflammatory disease.

Nongenomic cortisol signaling in fish

Glucocorticoids are critical regulators of the cellular processes that allow animals to cope with stressors. In teleosts, cortisol is the primary circulating glucocorticoid and this hormone mediates a suite of physiological responses, most importantly energy substrate mobilization that is essential for acute stress adaptation. Cortisol signaling has been extensively studied and the majority of work has been on the activation of the glucocorticoid receptor (GR), a ligand-bound transcription factor, and the associated downstream transcriptional and protein responses. Despite the role of this hormone in acute stress adaptation, very few studies have examined the rapid effects of this hormone on cellular function. The nongenomic corticosteroid effects, which are rapid (seconds to minutes) and independent of transcription and translation, involve changes to second-messenger pathways and effector proteins, but the primary receptors involved in this pathway activation remain elusive. In teleosts, a few studies suggested the possibility that GR located on the membrane may be initiating a rapid response based on the abrogation of this effect with RU486, a GR antagonist. However, studies have also proposed other signaling mechanisms, including a putative novel membrane receptor and changes to membrane biophysical properties as initiators of rapid signaling in response to cortisol stimulation. Emerging evidence suggests that cortisol activates multiple signaling pathways in cells to bring about rapid effects, but the underlying physiological implications on acute stress adaptation are far from clear.

Efficacy and safety of selective glucocorticoid receptor modulators in comparison to glucocorticoids in arthritis, a systematic review

Background

Long-term treatment with glucocorticoids (GCs) plays an important role in the management of arthritis patients, although the efficacy/safety balance is unfavorable. Alternatives with less (severe) adverse effects but with good efficacy are needed. Selective GC receptor modulators (SGRMs) are designed to engage the GC receptor with dissociative characteristics: transactivation of genes, which is mainly responsible for unwanted effects, is less strong while trans-repression of genes, reducing inflammation, is maintained. It is expected that SGRMs thus have a better efficacy/safety balance than GCs. A systematic review providing an overview of the evidence in arthritis is lacking.

Objective

To systematically review the current literature on efficacy and safety of oral SGRMs in comparison to GCs in arthritis.

Methods

A search was performed in Medline, Embase and the Cochrane Library, from inception dates of databases until May 2017. Experimental studies involving animal arthritis models or human material of arthritis patients, as well as clinical studies in arthritis patients were included, provided they reported original data. All types of arthritis were included. Data was extracted on the SGRM studied and on the GC used as reference standard; the design or setting of the study was extracted as well as the efficacy and safety results.

Results

A total of 207 articles was retrieved of which 17 articles were eligible for our analysis. Two studies concerned randomized controlled trials (RCT), five studies were pre-clinical studies using human material, and 10 studies involved pre-clinical animal models (acute and/or chronic arthritis induced in mice or rats). PF-04171327, the only compound investigated in a clinical trial setting, had a better efficacy/safety balance compared to GCs: better clinical anti-inflammatory efficacy and similar safety.

Conclusion

Studies assessing both efficacy and safety of SGRMs are scarce. There is limited evidence for dissociation of anti-inflammatory and metabolic effects of the SGRMs studied. Development of many SGRMs is haltered in a preclinical phase. One SGRM showed a better clinical efficacy/safety balance.

Inhibition of IRAK1 Ubiquitination Determines Glucocorticoid Sensitivity for TLR9-Induced Inflammation in Macrophages

Inflammatory responses are controlled by signaling mediators that are regulated by various posttranslational modifications. Recently, transcription-independent functions for glucocorticoids (GC) in restraining inflammation have emerged, but the underlying mechanisms are unknown. In this study, we report that GC receptor (GR)-mediated actions of GC acutely suppress TLR9-induced inflammation via inhibition of IL-1R-associated kinase 1 (IRAK1) ubiquitination. β-TrCP-IRAK1 interaction is required for K48-linked ubiquitination of IRAK1 at Lys¹³⁴ and subsequent membrane-to-cytoplasm trafficking of IRAK1 interacting partners TNFR-associated factor 6 and TAK1 that facilitates NF-κB and MAPK activation. Upon costimulation of macrophages with GC and TLR9-engaging ligand, GR physically interacts with IRAK1 and interferes with protein-protein interactions between β-TrCP and IRAK1. Ablation of GR in macrophages prevents GC-dependent suppression of β-TrCP-IRAK1 interactions. This GC-mediated suppression of IRAK1 activation is unique to TLR9, as GC treatment impairs TLR9 but not TLR4 ligand-induced K48-linked IRAK1 ubiquitination and trafficking of IRAK1 interacting partners. Furthermore, mutations in IRAK1 at Lys¹³⁴ prevent TLR9 ligand-induced activation of inflammatory signaling mediators and synthesis of proinflammatory cytokines to an extent comparable to GC-mediated inhibition. Collectively, these findings identify a transcription-independent, rapid, and nongenomic GC suppression of TLR9 ligand-mediated IRAK1 ubiquitination as a novel mechanism for restraining acute inflammatory reactions.

Checks and balances: The glucocorticoid receptor and NFĸB in good times and bad

Mutual regulation and balance between the endocrine and immune systems facilitate an organism's stress response and are impaired following chronic stress or prolonged immune activation. Concurrent alterations in stress physiology and immunity are increasingly recognized as contributing factors to several stress-linked neuropsychiatric disorders including depression, anxiety, and post-traumatic stress disorder. Accumulating evidence suggests that impaired balance and crosstalk between the glucocorticoid receptor (GR) and nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) - effectors of the stress and immune axes, respectively - may play a key role in mediating the harmful effects of chronic stress on mood and behavior. Here, we first review the molecular mechanisms of GR and NFκB interactions in health, then describe potential shifts in the GR-NFκB dynamics in chronic stress conditions within the context of brain circuitry relevant to neuropsychiatric diseases. Furthermore, we discuss developmental influences and sex differences in the regulation of these two transcription factors.

Rapid permissive action of dexamethasone on the regulation of blood pressure in a rat model of septic shock

Glucocorticoids (GCs) play a vital role in the regulation of blood pressure by their permissive effects in potentiating vasoactive responses to catecholamines through glucocorticoid receptors. GCs achieve this function by controlling vascular smooth muscle tone. Clinically, low to moderate doses of GCs are generally used in the treatment of septic shock in recent years. GCs are now known to have both genomic and non-genomic effects. While genomic effects of GCs were well studied, few non-genomic effects were reported, much less the non-genomic mechanisms. One of the most important characters of their non-genomic effects is short latency. The aim of this study was to determine whether GCs can rapidly regulate blood pressure by their permissive action on norepinephrine (NE). Adrenalectomized rats were subjected to cecal ligation and puncture to induce septic shock. The septic rats displayed a significant decrease in the blood pressure response to NE. Dexamethasone (DEX) rapidly restores this hyporeactivity to NE in adrenalectomized septic rats. Further studies showed that DEX potentiates the NE-induced shrinkage and actin cytoskeleton rearrangement of single cell from mesenteric arteries in a short time. These findings suggest that GCs probably exert their permissive actions on the pressure response to NE through rapid non-genomic mechanisms. In this article, we found that as an adjunctive therapy for septic shock, the use of GCs may involve a rapid permissive action, and non-genomic effects of GCs may be involved in these processes.

Effects of dietary nucleotides on growth, non-specific immune response and disease resistance of sea cucumber Apostichopus japonicas

A 9-week feeding trial was conducted to investigate the effects of dietary nucleotides (NT) on growth, immune response and disease resistance of sea cucumber Apostichopus japonicas (initial weight: 5.87 ± 0.03 g). Four graded levels of dietary NT were designed as 0, 150, 375 and 700 mg/kg, respectively. After the feeding trial, sea cucumbers were challenged with Vibrio splendidus for the determination of disease resistance. The results showed that the specific growth rates were significantly higher in sea cucumber fed the diet with 375 mg/kg NT than those fed the basal diet without NT supplementation (P < 0.05). The highest total coelomocytes counts in coelomic fluid were found in the treatment with 150 mg/kg of dietary NT (P < 0.05). Compared to those fed with the basal diet, sea cucumber fed diets with nucleotides (≥ 375 mg/kg) had significantly higher phagocytic activities in coelomic fluid (P < 0.05). Respiratory burst activities in coelomic fluid significantly increased with increasing dietary NT supplementations up to 700 mg/kg (P < 0.05). No significant differences in the activities of superoxide dismutase, total nitric oxide synthase and acid phosphatase in coelomic fluid were found among all the treatments (P > 0.05). After being challenged with V. splendidus, the cumulative mortalities of sea cucumber fed diets with 150 and 375 mg/kg NT were significantly lower than that in the treatment without dietary nucleotide supplementation (P < 0.05). Under the experimental conditions, the present results confirmed that a diet supplemented with 375 mg/kg NT is able to enhance both non-specific immune response and growth of sea cucumber in vivo. In conclusion, it was showed that dietary NT does increase the growth performance, non-specific immunity and disease resistance of sea cucumber. The optimum dietary NT supplementation level for sea cucumber was found to be 375 mg/kg. The application of dietary NT may present a novel strategy for health management in sea cucumber's aquaculture.

The Impaired Function of Macrophages Induced by Strenuous Exercise Could Not Be Ameliorated by BCAA Supplementation

The aim of this study was to evaluate the effect of strenuous exercise on the functions of peritoneal macrophages in rats and to test the hypothesis that branched-chain amino acid (BCAA) supplementation will be beneficial to the macrophages of rats from strenuous exercise. Forty male Wistar rats were randomly divided into five groups: (C) Control, E) Exercise, (E1) Exercise with one week to recover, (ES) Exercise + Supplementation and (ES1) Exercise + Supplementation with 1 week to recover. All rats except those of the sedentary control were subjected to four weeks of strenuous exercise. Blood hemoglobin, serum testosterone and BCAA levels were tested. Peritoneal macrophages functions were also determined at the same time. The data showed that hemoglobin, testosterone, BCAA levels, and body weight in group E decreased significantly as compared with that of group C. Meanwhile, phagocytosis capacity (decreased by 17.07%, p = 0.031), reactive oxygen species (ROS) production (decreased by 26%, p = 0.003) and MHC II mRNA (decreased by 22%, p = 0.041) of macrophages decreased in the strenuous exercise group as compared with group C. However, the chemotaxis of macrophages did not change significantly. In addition, BCAA supplementation could slightly increase the serum BCAA levels of rats from strenuous exercise (increased by 6.70%, p > 0.05). Moreover, the body weight, the blood hemoglobin, the serum testosterone and the function of peritoneal macrophages in group ES did not change significantly as compared with group E. These results suggest that long-term intensive exercise impairs the function of macrophages, which is essential for microbicidal capability. This may represent a novel mechanism of immunosuppression induced by strenuous exercise. Moreover, the impaired function of macrophage induced by strenuous exercise could not be ameliorated by BCAA supplementation in the dosing and timing used for this study.

The novel strategy of glucocorticoid drug development via targeting nongenomic mechanisms

Glucocorticoids (GCs) are widely used in clinical practice as potent anti-inflammatory and immunosuppressive agents. Unfortunately, they can also produce numerous and potentially serious side effects that limit their usage. This problem represents the driving force for the intensive search for novel GCs with a better benefit-risk ratio compared to conventional GCs. GCs are believed to take effects mainly through classical genomic mechanisms, which are also largely responsible for GCs' side effects. However, in addition to these genomic effects, GCs also demonstrate rapid genomic-independent activities. It has become increasingly evident that some of the anti-inflammatory, immunosuppressive, anti-allergic and anti-shock effects of GCs could be mediated through nongenomic mechanisms. Thus, theoretically, trying to use nongenomic mechanisms of GCs more intensively may represent a novel strategy for development of GCs with low side effect profile. The new GCs' drugs will take clinical effects mainly via nongenomic mechanisms and do not execute the classical genomic mechanism to reduce side effects.

An evaluation of replacing fish meal with fermented soybean meal in the diet of Macrobrachium nipponense: Growth, nonspecific immunity, and resistance to Aeromonas hydrophila

Partial or complete replacement of fish meal (FM) with fermented soybean meal (FSM) was examined in Macrobrachium nipponense over an 8-week growth trial. Growth and immune characteristics were evaluated. Fermented soybean meal replaced 0 (FM, control), 25% (R25), 50% (R50), 75% (R75), or 100% of the FM (R100) in five isocaloric and isonitrogenous diets. Each diet was fed to juvenile prawns (mean weight, 0.103 ± 0.0009 g) twice daily to apparent satiation in five replicates. Weight gain and specific growth rate of M. nipponense were significantly higher in prawns fed the R25 diet than that of prawns fed the FM diet. No significant differences were observed among the other treatments. Total hemocyte count and hemolymph phagocytic activity decreased as the proportion of FSM increased. Total antioxidant activity competence and malondialdehyde level in the hepatopancreas were highest in prawns fed the R100 diet. mRNA levels of the antioxidant genes Cu-Zn superoxide dismutase and catalase, heat shock cognate protein 70, and heat shock protein 90 were significantly differentially regulated in the prawn hepatopancreas. In addition, percent mortality increased after challenge with live Aeromonas hydrophila. Percent mortality of prawns fed the R100 diet was significantly higher than that of prawns fed the FM and R25 diets. These findings demonstrate that (1) M. nipponense growth performance was not affected by including a high proportion of FSM in the diet, and the best growth performance was obtained when 25% of the FM was replaced with FSM; (2) nonspecific immunity was impaired when all of the FM was replaced with FSM.

Stress-Induced Glucocorticoid Release Upregulates Uncoupling Protein-2 Expression and Enhances Resistance to Endotoxin-Induced Lethality

OBJECTIVE

Although psychological and/or physiological stress has been well documented to influence immune responses, the precise mechanism for immunomodulation remains to be elucidated. The present work describes the role of the hypothalamic-pituitary-adrenal (HPA) axis in the mechanism of stress-mediated enhanced-resistance to lethality after lipopolysaccharide (LPS) injection.

METHODS/RESULTS

Preconditioning with restraint stress (RS) resulted in enhanced activation of the HPA axis in response to LPS injection and suppressed LPS-induced release of proinflammatory cytokines and nitric oxide metabolites. Melanocortin 2 receptor-deficient mice (MC2R(-/-)) failed to increase plasma levels of glucocorticoids in response to LPS injection, and exhibited high sensitivity to LPS-induced lethality with enhanced release of proinflammatory cytokines as compared with MC2R(+/-) mice. Real-time PCR analysis revealed that RS induced upregulation of uncoupling protein-2 (UCP2) in macrophages in the lung and the liver of MC2R(+/-), but not of MC2R(-/-), mice. In addition, RS increased UCP2-dependent uncoupling activity of isolated mitochondria from the liver of MC2R(+/-), but not of MC2R(-/-), mice. In vitro study revealed that corticosterone and dexamethasone directly increased UCP2 expression in mouse RAW 264.7 macrophages and suppressed the generation of LPS-induced mitochondrial reactive oxygen species (ROS) and TNF-α production. Knockdown of UCP2 by small interfering RNA blunted the dexamethasone action for suppressing LPS-induced mitochondrial ROS and TNF-α production.

CONCLUSION

The present work suggests that RS enhances activation of the HPA axis to release glucocorticoids and upregulation of UCP2 in macrophages, thereby increasing the resistance to endotoxin-induced systemic inflammation and death.

Cross-talk between HPA-axis-increased glucocorticoids and mitochondrial stress determines immune responses and clinical manifestations of patients with sepsis

Various stressors activate the hypothalamo-pituitary-adrenal axis (HPA-axis) that stimulates adrenal secretion of glucocorticoids, thereby playing critical roles in the modulation of immune responses. Transcriptional regulation of nuclear genes has been well documented to underlie the mechanism of glucocorticoid-dependent modulation of cytokine production and immune reactions. Glucocorticoids also regulate inflammatory responses via non-genomic pathways in cytoplasm and mitochondria. Recent studies have revealed that glucocorticoids modulate mitochondrial calcium homeostasis and generation of reactive oxygen species (ROS). Although redox status and ROS generation in inflammatory cells have been well documented to play important roles in defense against pathogens, the roles of glucocorticoids and mitochondria in the modulation of immunological responses remain obscure. This review describes the role of stress-induced activation of the HPA-axis and glucocorticoid secretion by the adrenal gland in mitochondria-dependent signaling pathways that modulate endotoxin-induced inflammatory reactions and innate immunity.

Glucocorticoid treatment and endocrine pancreas function: implications for glucose homeostasis, insulin resistance and diabetes

Glucocorticoids (GCs) are broadly prescribed for numerous pathological conditions because of their anti-inflammatory, antiallergic and immunosuppressive effects, among other actions. Nevertheless, GCs can produce undesired diabetogenic side effects through interactions with the regulation of glucose homeostasis. Under conditions of excess and/or long-term treatment, GCs can induce peripheral insulin resistance (IR) by impairing insulin signalling, which results in reduced glucose disposal and augmented endogenous glucose production. In addition, GCs can promote abdominal obesity, elevate plasma fatty acids and triglycerides, and suppress osteocalcin synthesis in bone tissue. In response to GC-induced peripheral IR and in an attempt to maintain normoglycaemia, pancreatic β-cells undergo several morphofunctional adaptations that result in hyperinsulinaemia. Failure of β-cells to compensate for this situation favours glucose homeostasis disruption, which can result in hyperglycaemia, particularly in susceptible individuals. GC treatment does not only alter pancreatic β-cell function but also affect them by their actions that can lead to hyperglucagonaemia, further contributing to glucose homeostasis imbalance and hyperglycaemia. In addition, the release of other islet hormones, such as somatostatin, amylin and ghrelin, is also affected by GC administration. These undesired GC actions merit further consideration for the design of improved GC therapies without diabetogenic effects. In summary, in this review, we consider the implication of GC treatment on peripheral IR, islet function and glucose homeostasis.

Budesonide added to modified porcine surfactant Curosurf may additionally improve the lung functions in meconium aspiration syndrome

Severe meconium aspiration syndrome (MAS) in newborns is often treated by exogenous surfactant. Because its efficacy is reduced by meconium-induced inflammation, glucocorticoid budesonide was added into surfactant preparation Curosurf to enhance efficacy of the surfactant therapy in experimental model of MAS. Oxygen-ventilated rabbits were intratracheally given meconium (25 mg/ml, 4 ml/kg) to induce respiratory failure. Thirty minutes later, animals were treated by intratracheal budesonide (0.25 mg/kg) or surfactant lung lavage (10 ml/kg, 5 mg phospholipids/ml) repeated twice, followed by undiluted Curosurf (100 mg phospholipids/kg) or by the above mentioned surfactant treatment with the last surfactant dose fortified with budesonide (0.25 mg/kg) or were untreated. Animals were ventilated for additional 5 hours and respiratory parameters were measured regularly. After sacrificing animals, wet-dry lung weight ratio was evaluated and plasma levels of interleukins (IL)-1beta, -6, -8, and TNF-alpha were measured by ELISA method. Efficacy of the given therapies to enhance lung functions and to diminish lung edema formation and inflammation increased from budesonide-only and surfactant-only therapy to surfactant+budesonide therapy. Combined therapy improved gas exchange from 30 min of administration, and showed a longer-lasting effect than surfactant-only therapy. In conclusions, budesonide additionally improved the effects of exogenous surfactant in experimental MAS.

The effect of indomethacin, myeloperoxidase, and certain steroid hormones on bactericidal activity: an ex vivo and in vivo experimental study

BACKGROUND

The role of myeloperoxidase (MPO) is essential in the killing of phagocytosed bacteria. Certain steroid hormones increase MPO plasma concentration. Our aim was to test the effect of MPO, its inhibitor indomethacin, and certain steroid hormones on bactericidal activity.

METHODS

Human polymorphonuclear leukocytes (PMN) were incubated with opsonised Escherichia coli and either MPO, indomethacin, estradiol, or hydrocortisone. Intracellular killing capacity was evaluated with UV microscopy after treatment with fluorescent dye. Next, an in vivo experiment was performed with nine groups of rats: in the first phase of the study indomethacin treatment and Pasteurella multocida infection (Ii), indomethacin treatment without infection (I0), untreated control with infection (Mi) and untreated control without infection (M0); in the second phase of the study rats with infection and testosterone treatment (NT), castration, infection and testosterone treatment (CT), castration, infection and estradiol treatment (CE), non-castrated infected control (N0), and castrated infected control (C0). After treatment bacteria were reisolated from the liver and heart blood on agar plates, and laboratory parameters were analyzed. For the comparison of laboratory results ANOVA or Kruskal-Wallis test and LSD post hoc test was used.

RESULTS

Indomethacin did not have a remarkable effect on the bacterial killing of PMNs, while the other compounds increased bacterial killing to various degrees. In the animal model indomethacin and infection caused a poor clinical state, a great number of reisolated bacteria, elevated white blood cell (WBC) count, decreased C-reactive protein (CRP) and serum albumin levels. Testosterone treatment resulted in less bacterial colony numbers in group NT, but not in group CT compared to respective controls (N0, C0). Estradiol treatment (CE) decreased colony numbers compared to control (C0). Hormone administration resulted in lower WBC counts, and in group CE, a decreased CRP.

CONCLUSIONS

MPO, estradiol, and hydrocortisone improve bacterial killing activity of PMNs. Indomethacin treatment and castration weaken immune responses and clinical state of infected rats, while testosterone and estradiol have a beneficial effect.

Why do we need nongenomic glucocorticoid mechanisms?

Glucocorticoids (GCs) are a class of steroid hormones that have been known to be involved in various physiological processes and to play a pivotal role in preserving basal and stress-related homeostasis. GCs are also widely used clinically as anti-inflammatory, immunosuppressive, anti-shock drugs. It is believed traditionally that GCs exert most of their effects genomically. In addition to the well-known classical genomic mechanisms, GCs also affect various functions via rapid, nongenomic mechanisms. The therapeutic benefits of nongenomic GC actions have been exploited in clinical medicine, especially with high-dose pulsed glucocorticoid administration. However, it is certainly not the case that the inherent nongenomic glucocorticoid mechanisms evolved only for their clinical utility. Here, we review the recent literature on nongenomic actions of GCs related to stress and the physiological significance of these actions, and we propose reasons why nongenomic mechanisms of GC actions are needed.

Modulation of Human Colostrum Phagocyte Activity by the Glycine-Adsorbed Polyethylene Glycol Microspheres

Colostrum is a secretion that contains immunologically active components, including immunocompetent cells and glycine, which has anti-inflammatory, immunomodulatory, and cytoprotective effects. The aim of this study was to evaluate the adsorption of glycine onto polyethylene glycol (PEG) microspheres and to verify the immunomodulatory effect of this nanomaterial on human colostrum phagocytes. The PEG microspheres were evaluated by fluorescence microscopy. The effects of PEG microspheres with adsorbed glycine on viability, superoxide release, phagocytosis, microbicidal activity, and intracellular calcium release of mononuclear (MN) and polymorphonuclear (PMN) colostrum phagocytes were determined. Fluorescence microscopy analyses revealed that glycine was able to be adsorbed to the PEG microspheres. The PMN phagocytes exposed to glycine-PEG microspheres showed the highest superoxide levels. The phagocytes (both MN and PMN) displayed increased microbicidal activity and intracellular calcium release in the presence of PEG microspheres with adsorbed glycine. These data suggest that the adsorption of PEG microspheres with adsorbed glycine was able to stimulate the colostrum phagocytes. This material may represent a possible alternative therapy for future clinical applications on patients with gastrointestinal infections.

Effects of Acer okamotoanum sap on the function of polymorphonuclear neutrophilic leukocytes in vitro and in vivo

Sap is a plant fluid that primarily consists of water and small amounts of mineral elements, sugars, hormones and other nutrients. Acer mono (A. mono) is an endemic Korean mono maple which was recently suggested to have health benefits due to its abundant calcium and magnesium ion content. In the present study, we examined the effects of sap from Acer okamotoanum (A. okamotoanum) on the phagocytic response of mouse neutrophils in vivo and rat and canine neutrophils in vitro. We tested the regulation of phagocytic activity, oxidative burst activity (OBA) and the levels of filamentous polymeric actin (F-actin) in the absence and presence of dexamethasone (DEX) in vitro and in vivo. Our results showed that DEX primarily reduced OBA in the mouse neutrophils, and that this was reversed in the presence of the sap. By contrast, the phagocytic activity of the mouse cells was not regulated by either DEX or the sap. Rat and canine polymorphonuclear neutrophilic leukocytes (PMNs) responded in vitro to the sap in a similar manner by increasing OBA. However, regulation of phagocytic activity by the sap was different between the species. In canine PMNs, phagocytic activity was enhanced by the sap at a high dose, while it did not significantly modulate this activity in rat PMNs. These findings suggest that the sap of A. okamotoanum stimulates neutrophil activity in the mouse, rat and canine by increasing OBA in vivo and in vitro, and thus may have a potential antimicrobial effect in the PMNs of patients with infections.

Effect of academic psychological stress in post-graduate students: the modulatory role of cortisol on superoxide release by neutrophils

Experimental and clinical evidence shows that neutrophils play an important role in the mechanism of tissue injury in immune complex diseases through the generation of reactive oxygen species. In this study, we examined the influence of academic psychological stress in post-graduate students on the capacity of their blood neutrophils to release superoxide when stimulated by immune complexes bound to nonphagocytosable surfaces and investigated the modulatory effect of cortisol on this immune function. The tests were performed on the day before the final examination. The state-trait anxiety inventory questionnaire was used to examine whether this stressful event caused emotional distress. In our study, the psychological stress not only increased plasma cortisol concentration, but it also provoked a reduction in superoxide release by neutrophils. This decrease in superoxide release was accompanied by diminished mRNA expression for subunit p47(phox) of the phagocyte superoxide-generating nicotinamide adenine dinucleotide phosphate-oxidase. These inhibitory effects were also observed by in vitro exposure of neutrophils from control volunteers to 10(- 7) M hydrocortisone, and could be prevented by the glucocorticoid receptor antagonist RU-486. These results show that in a situation of psychological stress, the increased levels of cortisol could inhibit superoxide release by neutrophils stimulated by IgG immune complexes bound to nonphagocytosable surfaces, which could attenuate the inflammatory state.

A novel strategy for development of glucocorticoids through non-genomic mechanism

Glucocorticoids (GCs) are routinely believed to take effect through genomic mechanisms, which are also largely responsible for GCs' side effects. Beneficial non-genomic effects of GCs have been reported as being independent of the genomic pathway. Here, we synthesized a new type of GCs, which took effect mainly via non-genomic mechanisms. Hydrocortisone was conjugated with glycine, lysine and phenylalanine to get a bigger molecular structure, which could hardly go through the cell membrane. Evaluation of the anti-inflammatory efficacy showed that hydrocortisone-conjugated glycine (HG) and lysine could inhibit neutrophil degranulation within 15 min. HG could inhibit IgE-mediated histamine release from mast cells via a non-genomic pathway, and rapidly alleviate allergic reaction. Luciferase reporter assay showed that HG would not activate the glucocorticoid response element within 30 min, which verified the rapid effects independent of the genomic pathway. The work proposes a novel insight into the development of novel GCs, and provides new tools for experimental study on non-genomic mechanisms.

A meta-analysis of glucocorticoids as modulators of oxidative stress in vertebrates

Prolonged high secretion of glucocorticoids normally reflects a state of chronic stress, which has been associated with an increase in disease susceptibility and reduction in Darwinian fitness. Here, we hypothesize that an increase in oxidative stress accounts for the detrimental effects of prolonged high secretion of glucocorticoids. We performed a meta-analysis on studies where physiological stress was induced by administration of glucocorticoids to evaluate the magnitude of their effects on oxidative stress. Glucocorticoids have a significant effect on oxidative stress (Pearson r = 0.552), although this effect depends on the duration of treatment, and is larger in long-term experiments. Importantly, there was a significant effect on tissue, with brain and heart being the most and the least susceptible to GC-induced oxidative stress, respectively. Furthermore, effect size was larger (1) in studies using both sexes compared to males only, (2) when corticosterone rather than dexamethasone was administered and (3) in juveniles than in adults. These effects were not confounded by species, biochemical biomarker, or whether wild or laboratory animals were studied. In conclusion, our meta-analysis suggests that GC-induced oxidative stress could be a further mechanism underlying increases in disease susceptibility and decreases in Darwinian fitness observed under chronic stress.

Molecular mechanisms of glucocorticoids action: implications for treatment of rhinosinusitis and nasal polyposis

Intra-nasal glucocorticoids are the most effective drugs available for rhinosinusitis and nasal polyposis treatment. Their effectiveness depends on many factors and not all of them have been well recognized so far. The authors present the basic information on molecular mechanisms of glucocorticoid action, direct and indirect effects of glucocorticoids on transcription of genes encoding inflammatory mediators. They focus on recently proved nongenomic mechanisms which appear quickly, from several seconds to minutes after glucocorticoid administration and discuss clinical implications resulting from this knowledge. Discovery of nongenomic glucocorticoid actions allows for better use of these drugs in clinical practice.

Anti-inflammatory effect of bee venom on antigen-induced arthritis in rabbits: influence of endogenous glucocorticoids

AIM OF THE STUDY

This study assessed the involvement of endogenous glucocorticoids (GCs) in the anti-arthritic properties of bee venom (BV) on antigen-induced arthritis (AIA) in rabbits.

MATERIALS AND METHODS

BV (1.5-6 microg/kg/day) was injected for 7 days before AIA induction, whereas the control group received sterile saline. The total and differential leukocyte count, PGE(2) levels in synovial fluid and synovial membrane cell infiltrate were evaluated. The contribution of GCs to BV action was assessed in rabbits treated with BV plus metyrapone, an inhibitor of GC synthesis, or RU-38 486, a steroid antagonist.

RESULTS

Treatment with BV (1.5 microg/kg/day) reduced the leukocyte count and PGE(2) level (18571+/-1909 cells/mm(3) and 0.49+/-0.05 ng/mL, respectively) as well as the cellular infiltrate compared with the control group (40968+/-5248 cells/mm(3) and 2.92+/-0.68 ng/mL, p<0.05). The addition of metyrapone to BV treatment completely reversed the inhibition of AIA, whereas RU-38 486 was ineffective.

CONCLUSION

Our data show that bee venom treatment prevents the development of antigen-induced arthritis in rabbits through the action of GCs.

Corticosterone exerts immunostimulatory effects on macrophages via endoplasmic reticulum stress

BACKGROUND

: Glucocorticoids are the central effector hormones for the hypothalamic-pituitary-adrenal axis. However, the effects of endogenous glucocorticoids on the immune system are not understood completely.

METHODS

: Macrophage function (adherence, chemotaxis and cytokine production) was assessed in the presence of increasing concentrations of corticosterone. The role of endoplasmic reticulum (ER) stress in corticosterone immunoregulation was determined with thapsigargin and plasmid pGCL-GFP-siXBP1. Mifepristone was used to determine the role of glucocorticoid receptor in the corticosterone-induced ER stress response.

RESULTS

: Corticosterone exerted immunostimulatory effects on macrophage function at low concentrations. No effects were observed at high concentrations in the absence of immunological stimulation. Low-dose corticosterone induced ER stress, which was correlated to the corticosterone immunostimulatory activities. Expression of X box-binding protein (XBP) 1, but not activating transcription factor 6, was significantly increased at both mRNA and protein levels only in the presence of low-dose corticosterone. Inhibition of XBP1 expression with small interfering RNA significantly inhibited the corticosterone immunostimulatory effects. In addition, pretreatment of macrophages with mifepristone significantly inhibited the expression of glucose response protein 78 and XBP1 in macrophages by low-dose corticosterone.

CONCLUSION

: At low concentrations, endogenous glucocorticoids exert immunostimulatory actions on macrophages. The underlying mechanisms may be correlated to ER stress via the glucocorticoid receptor, in which XBP1 plays an important role.

Randomized study of interferon beta-1a, low-dose azathioprine, and low-dose corticosteroids in multiple sclerosis

Background

Studies evaluating interferon beta (IFNβ) for multiple sclerosis (MS) showed only partial efficacy. In many patients, IFNβ does not halt relapses or disability progression. One strategy to potentially enhance efficacy is to combine IFNβ with classical immunosuppressive agents, such as azathioprine (AZA) or corticosteroids, commonly used for other autoimmune disorders.

Objective

The Avonex–Steroids–Azathioprine study was placebo-controlled trial and evaluated efficacy of IFNβ-1a alone and combined with low-dose AZA alone or low-dose AZA and low-dose corticosteroids as initial therapy.

Methods

A total of 181 patients with relapsing–remitting MS (RRMS) were randomized to receive IFNβ-1a 30 μg intramuscularly (IM) once weekly, IFNβ-1a 30 μg IM once weekly plus AZA 50 mg orally once daily, or IFNβ-1a 30 μg IM once weekly plus AZA 50 mg orally once daily plus prednisone 10 mg orally every other day. The primary end point was annualized relapse rate (ARR) at 2 years. Patients were eligible for enrollment in a 3-year extension.

Results

At 2 years, adjusted ARR was 1.05 for IFNβ-1a, 0.91 for IFNβ-1a plus AZA, and 0.73 for combination. The cumulative probability of sustained disability progression was 16.8% for IFNβ-1a, 20.7% for IFNβ-1a plus AZA, and 17.5% for combination. There were no statistically significant differences among groups for either measure at 2 and 5 years. Percent T2 lesion volume change at 2 years was significantly lower for combination (+14.5%) versus IFNβ-1a alone (+30.3%, P < 0.05). Groups had similar safety profiles.

Conclusion

In IFNβ-naïve patients with early active RRMS, combination treatment did not show superiority over IFNβ-1a monotherapy.

Cromoglycate drugs suppress eicosanoid generation in U937 cells by promoting the release of Anx-A1

Using biochemical, epifluorescence and electron microscopic techniques in a U937 model system, we investigated the effect of anti-allergic drugs di-sodium cromoglycate and sodium nedocromil on the trafficking and release of the anti-inflammatory protein Annexin-A1 (Anx-A1) when this was triggered by glucocorticoid (GC) treatment. GCs alone produced a rapid (within 5 min) concentration-dependent activation of PKCα/β (Protein Kinase C; EC 2.7.11.13) and phosphorylation of Anx-A1 on Ser²⁷. Both phosphoproteins accumulated at the plasma membrane and Anx-A1 was subsequently externalised thereby inhibiting thromboxane (Tx) B₂ generation. When administered alone, cromoglycate or nedocromil had little effect on this pathway however, in the presence of a fixed sub-maximal concentration of GCs, increasing amounts of the cromoglycate-like drugs caused a striking concentration-dependent enhancement of Anx-A1 and PKCα/β phosphorylation, membrane recruitment and Anx-A1 release from cells resulting in greatly enhanced inhibition of TxB₂ generation. GCs also stimulated phosphatase accumulation at the plasma membrane of U937 cells. Both cromoglycate and nedocromil inhibited this enzymatic activity as well as that of a highly purified PP2A phosphatase preparation. We conclude that stimulation by the cromoglycate-like drugs of intracellular Anx-A1 trafficking and release (hence inhibition of eicosanoid release) is secondary to inhibition of a phosphatase PP2A (phosphoprotein phosphatase; EC 3.1.3.16), which probably forms part of a control loop to limit Anx-A1 release. These experiments provide a basis for a novel mechanism of action for the cromolyns, a group of drugs that have long puzzled investigators.