Glucocorticoids up-regulate constitutive interleukin-10 production by human monocytes

Biomaterial-mediated intracellular control of macrophages for cell therapy in pro-inflammatory and pro-fibrotic conditions

Macrophages are key modulators of all inflammatory diseases and essential for their resolution, making macrophage cell therapy a promising strategy for regenerative medicine. However, since macrophages change rapidly in response to microenvironmental cues, their phenotype must be controlled post-administration. We present a tunable biomaterial-based strategy to control macrophages intracellularly via small molecule-releasing microparticles. Poly(lactic-co-glycolic acid) microparticles encapsulating the anti-inflammatory and anti-fibrotic drug dexamethasone were administered to macrophages in vitro, with uptake rates controlled by different loading regimes. Microparticle dose and dexamethasone content directly affected macrophage phenotype and phagocytic capacity, independent of particle content per cell, leading to an overall pro-reparative, anti-inflammatory, anti-fibrotic phenotype with increased phagocytic and ECM degrading functionality. Intracellularly controlled macrophages partially maintained this phenotype in vivo in a murine pulmonary fibrosis model, with more prominent effects in a pro-fibrotic environment compared to pro-inflammatory. These results suggest that intracellular control using biomaterials has the potential to control macrophage phenotype post-administration, which is essential for successful macrophage cell therapy.

Chronic Glucocorticoid Use and Risk for Advanced Prostate Cancer at Presentation: A SEER-Medicare Cohort Study

BACKGROUND

Examine the relationship between exposure to systemic glucocorticoids (steroids) and advanced prostate cancer (PCa) at presentation. Prior work suggested that steroid use may be associated with increased PCa risk.

MATERIALS AND METHODS

We queried the linked SEER-Medicare database (2004-2015) to identify PSA screened patients diagnosed with PCa. Criteria for screening included a PSA lab test or DRE exam in both the 12 month and 13 to 36 month periods prior to diagnosis of PCa. Steroid exposure was determined using Medicare Part D and groups were divided based on duration of use in the 3 years prior to diagnosis: controls with no exposure, <30 days, 30 days - 1 year, 1 to 2 years, and >2+ years. Advanced PCa was defined as systemic metastases or regional lymph node metastasis at presentation. Risk estimates for advanced PCa at presentation for steroid exposure groups vs. controls were assessed with univariable and multivariable logistic regression models.

RESULTS

We identified 22,920 PSA screened patients diagnosed with PCa of which 29% used glucocorticoids in the exposure period. The mean (SD) duration for glucocorticoid use (in days) among all steroid users was 76.7 days (192.1). On univariable and multivariable analyses, > 2 years of steroid exposure was associated with significantly increased risk for advanced PCa (OR 2.06, 95% CI 1.35-3.14 and OR 1.74, 95% CI 1.12-2.69, respectively).

CONCLUSION

In this population-based PSA-screened cohort, prolonged steroid use was associated with increased risk of advanced PCa at diagnosis. With the widespread use of glucocorticoids, it is important to consider the role steroids may play in PCa pathogenesis.

Gut-Brain Interactions and Their Impact on Astrocytes in the Context of Multiple Sclerosis and Beyond

Multiple Sclerosis (MS) is a chronic autoimmune inflammatory disease of the central nervous system (CNS) that leads to physical and cognitive impairment in young adults. The increasing prevalence of MS underscores the critical need for innovative therapeutic approaches. Recent advances in neuroimmunology have highlighted the significant role of the gut microbiome in MS pathology, unveiling distinct alterations in patients' gut microbiota. Dysbiosis not only impacts gut-intrinsic processes but also influences the production of bacterial metabolites and hormones, which can regulate processes in remote tissues, such as the CNS. Central to this paradigm is the gut-brain axis, a bidirectional communication network linking the gastrointestinal tract to the brain and spinal cord. Via specific routes, bacterial metabolites and hormones can influence CNS-resident cells and processes both directly and indirectly. Exploiting this axis, novel therapeutic interventions, including pro- and prebiotic treatments, have emerged as promising avenues with the aim of mitigating the severity of MS. This review delves into the complex interplay between the gut microbiome and the brain in the context of MS, summarizing current knowledge on the key signals of cross-organ crosstalk, routes of communication, and potential therapeutic relevance of the gut microbiome. Moreover, this review places particular emphasis on elucidating the influence of these interactions on astrocyte functions within the CNS, offering insights into their role in MS pathophysiology and potential therapeutic interventions.

Circulating and Synovial Monocytes in Arthritis and Ex-Vivo Model to Evaluate Therapeutic Modulation of Synovial Monocytes

Monocytes are innate immune cells that play a dual role in protection of host against pathogens and initiation and perpetuation of inflammatory disorders including joint diseases. During inflammation, monocytes migrate from peripheral blood to tissues via chemokine receptors where they produce inflammatory factors. Monocytes are classified into three subsets, namely: classical, intermediate and non-classical, each subset has particular function. Synovium of patients with inflammatory joint diseases, such as rheumatoid arthritis and psoriatic arthritis as well as osteoarthritis, is enriched by monocytes that differ from circulatory ones by distinct subsets distribution. Several therapeutic agents used systemically or locally through intra-articular injections in arthritis management modulate monocyte subsets. This scoping review summarized the existing literature delineating the effect of common therapeutic agents used in arthritis management on circulating and synovial monocytes/macrophages. As certain agents have an inhibitory effect on monocytes, we propose to test their potential to inhibit synovial monocytes via an ex-vivo platform based on cultured synovial fluid mononuclear cells derived from patients with rheumatic diseases. Information obtained from the ex-vivo platform can be applied to explore the therapeutic potential of medications in clinical practice.

The Effects of Probiotic Bacillus Spores on Dexamethasone-Treated Rats

Glucocorticoids are effective anti-inflammatory and immunosuppressive agents. Long-term exposure is associated with multiple metabolic side effects. Spore-forming probiotic bacteria have shown modulatory properties regarding glycolipid metabolism and inflammation. The aim of this study was to evaluate, for the first time, the effects of Bacillus species spores (B. licheniformis, B. indicus, B. subtilis, B. clausii, and B. coagulans) alone and in combination with metformin against dexamethasone-induced systemic disturbances. A total of 30 rats were randomly divided into 5 groups: group 1 served as control (CONTROL), group 2 received dexamethasone (DEXA), group 3 received DEXA and MegaSporeBiotic (MSB), group 4 received DEXA and metformin (MET), and group 5 received DEXA, MSB, and MET. On the last day of the experiment, blood samples and liver tissue samples for histopathological examination were collected. We determined serum glucose, total cholesterol, triglycerides, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-10 (IL-10), catalase, total antioxidant capacity (TAC), and metformin concentration. DEXA administration caused hyperglycemia and hyperlipidemia, increased inflammation cytokines, and decreased antioxidant markers. Treatment with MSB reduced total cholesterol, suggesting that the administration of Bacillus spores-based probiotics to DEXA-treated rats could ameliorate metabolic parameters.

Adipocyte Glucocorticoid Receptor Inhibits Immune Regulatory Genes to Maintain Immune Cell Homeostasis in Adipose Tissue

Glucocorticoids acting via the glucocorticoid receptors (GR) are key regulators of metabolism and the stress response. However, uncontrolled or excessive GR signaling adversely affects adipose tissue, including endocrine, immune, and metabolic functions. Inflammation of the adipose tissue promotes systemic metabolic dysfunction; however, the molecular mechanisms underlying the role of adipocyte GR in regulating genes associated with adipose tissue inflammation are poorly understood. We performed in vivo studies using adipocyte-specific GR knockout mice in conjunction with in vitro studies to understand the contribution of adipocyte GR in regulating adipose tissue immune homeostasis. Our findings show that adipocyte-specific GR signaling regulates adipokines at both mRNA and plasma levels and immune regulatory (Coch, Pdcd1, Cemip, and Cxcr2) mRNA gene expression, which affects myeloid immune cell presence in white adipose tissue. We found that, in adipocytes, GR directly influences Cxcr2. This chemokine receptor promotes immune cell migration, indirectly affecting Pdcd1 and Cemip gene expression in nonadipocyte or stromal cells. Our findings suggest that GR adipocyte signaling suppresses inflammatory signals, maintaining immune homeostasis. We also found that GR signaling in adipose tissue in response to stress is sexually dimorphic. Understanding the molecular relationship between GR signaling and adipose tissue inflammation could help develop potential targets to improve local and systemic inflammation, insulin sensitivity, and metabolic health.

Modulation of inflammatory and oxidative stress biomarkers due to dexamethasone exposure in chicken splenocytes

Dexamethasone (DEXA) is a potent corticosteroid, commonly used for treating inflammatory, hypersensitive and allergic conditions. It is administered to birds with tumours. Many studies were conducted on its immunosuppressive effects; however none of the similar study is available employing chicken splenocytes culture system. The present study was conducted to assess DEXA induced alterations in inflammatory and oxidative stress biomarkers in chicken splenocytes due to its in vitro exposure. The maximum non-cytotoxic dose (MNCD) was evaluated and was further used for conducting lymphocytes proliferation assay (LPA), antioxidant assays (lipid peroxidation, GSH, superoxide dismutase and nitric oxide assays) and assessment of mRNA levels of various genes (IL-1β, IL-6, IL-10, LITAF, iNOS, NF-κB1, Nrf-2, Caspase-3 and -9) through qPCR. The MNCD was determined to be 30 ng/ml in chicken splenocytes culture system. DEXA caused reduction in B and T lymphocytes proliferation indicating its immunosuppressive effects, however improved the antioxidant status of the exposed splenocytes. The expression levels of IL-1β, IL-6, iNOS, LITAF and NF-κB1 were significantly reduced while IL-10 was enhanced, which signify potent anti-inflammatory potential of DEXA. NF-κB is a major transcription factor that regulates genes responsible for both, innate and adaptive immune responses and elicits inflammation. The nuclear factor erythroid 2-related factor 2 (Nrf-2) level was found to be up-regulated. Nrf-2 plays important role in combating the oxidant stress and its increased expression could be the reason of improved antioxidant status of DEXA exposed cells. Present findings indicated that DEXA exhibited modulation in anti-inflammatory, immunomodulatory and antioxidant mediators in chicken splenocytes.

Targeting miR-223 enhances myeloid-derived suppressor cell suppressive activities in multiple sclerosis patients

BACKGROUND

Multiple sclerosis (MS) is an incurable autoimmune inflammatory demyelinating disease of the central nervous system. Several MS medications can modify disease course through effects on adaptive immune cells, while drugs targeting innate immunity are under investigation. Myeloid-derived suppressor cells (MDSCs) which arise during chronic inflammation, are defined by their T-cell immunosuppressive functions. MiR-223 modulates myeloid cell maturation and expansion, including MDSCs.

METHODS

MDSCs isolated from healthy controls (HC) and people with MS (pwMS) were co-cultured with CD4+ T-cells to study their immunosuppressive activities in vitro. Cytokines and chemokines concentration were evaluated by Luminex assay in the serum of HC, pwMS, and other neuroinflammatory diseases and correlated with MDSC activities.

RESULTS

MDSC suppressive functions are dysregulated in pwMS compared to HC, which was reversed by glucocorticoids (GC). GC specifically downregulated miR-223 levels in MDSCs and increased the expression of STAT3. In vitro assay showed that miR-223 inhibition enhanced MDSC suppressive activity, STAT3 dependently. By multiple linear regression analysis, we demonstrated that MDSC phosphorylated STAT3 was correlated with serum GM-CSF in HC and pwMS.

CONCLUSIONS

These results suggest that miR-223 could be a therapeutic target for enhancing MDSC's suppressive activities as an alternative to GC.

Impact of Betamethasone Pretreatment on Engrafment of Cord Blood-Derived Hematopoietic Stem Cells

Hematopoietic stem cell (HSC) transplantation is crucial to cure hematologic malignancies. Umbilical cord blood (UCB) is a source of stem cells, but 90% of UCB units are discarded due to low cellularity. Improving the engraftment capacities of CD34⁺ stem cells would allow the use of UCB that were so far rejected. Betamethasone induces long-term transcriptomic and epigenomic changes in immune cells through glucocorticoid receptor. We hypothesize that discarded UCB could be used owing to improvements induced by betamethasone. Isolated CD34⁺ HSC from UCB were exposed to the synthetic glucocorticoids betamethasone and fluticasone for 20 h, and cell phenotype was determined before transplantation. NSG mice were sub-lethally irradiated (1 Gy or 2 Gy) 6 h before intravenously transferring 2-5 × 10⁵ CD34⁺ HSC. The peripheral blood engraftment levels and the leukocyte subsets were followed up for 20 weeks using flow cytometry. At end point, the engraftment and leukocyte subsets were determined in the spleen and bone marrow. We demonstrated that betamethasone has surprising effects in recovering immune system homeostasis. Betamethasone and fluticasone increase CXCR4 and decrease HLA class II and CD54 expression in CD34⁺ HSCs. Both glucocorticoids-exposed cells showed a similar engraftment in 2 Gy-irradiated NSG mice. Interestingly, betamethasone-exposed cells showed enhanced engraftment in 1 Gy-irradiated NSG mice, with a trend to increase regulatory T cell percentage when compared to control. Betamethasone induces alterations in CD34⁺ HSCs and improve the engraftment, leading to a faster immune system recovery, which will contribute to engrafted cells survival.

Corticosteroids: A boon or bane for COVID-19 patients?

Several drugs and antibodies have been repurposed to treat COVID-19. Since the outcome of the drugs and antibodies clinical studies have been mostly inconclusive or with lesser effects, therefore the need for alternative treatments has become unavoidable. However, corticosteroids, which have a history of therapeutic efficacy against coronaviruses (SARS and MERS), might emerge into one of the pandemic's heroic characters. Corticosteroids serve an immunomodulatory function in the post-viral hyper-inflammatory condition (the cytokine storm, or release syndrome), suppressing the excessive immunological response and preventing multi-organ failure and death. Therefore, corticosteroids have been used to treat COVID-19 patients for more than last two years. According to recent clinical trials and the results of observational studies, corticosteroids can be administered to patients with severe and critical COVID-19 symptoms with a favorable risk-benefit ratio. Corticosteroids like Hydrocortisone, dexamethasone, Prednisolone and Methylprednisolone has been reported to be effective against SARS-CoV-2 virus in comparison to that of non-steroid drugs, by using non-genomic and genomic effects to prevent and reduce inflammation in tissues and the circulation. Clinical trials also show that inhaled budesonide (a synthetic corticosteroid) increases time to recovery and has the potential to reduce hospitalizations or fatalities in persons with COVID-19. There is also a brief overview of the industrial preparation of common glucocorticoids.

Birth triggers an inflammatory response in the neonatal periphery and brain

Birth is preceded by inflammation at the fetal/maternal interface. Additionally, the newborn experiences stimuli that under any other circumstance could elicit an immune response. It is unknown, however, whether birth elicits an inflammatory response in the newborn that extends to the brain. Moreover, it is unknown whether birth mode may alter such a response. To study these questions, we first measured corticosterone and pro- and anti-inflammatory cytokines in plasma of mouse offspring at several timepoints spaced closely before and after a vaginal or Cesarean birth. We found highest levels of IL-6 one day before birth and surges in corticosterone and IL-10 just after birth, regardless of birth mode. We next examined the neuroimmune response by measuring cytokine mRNA expression and microglial number and morphology in the paraventricular nucleus of the hypothalamus and hippocampus around the time of birth. We found a marked increase in TNF-α expression in both brain regions a day after birth, and rapid increases in microglial cell number in the first three days postnatal, with subtle differences by birth mode. To test whether the association between birth and cytokine production or expansion of microglia is causal, we manipulated birth timing. Remarkably, advancing birth by a day advanced the increases in all of the markers tested. Thus, birth triggers an immune response in the body and brain of offspring. Our results may provide a mechanism for effects of birth (e.g., acute changes in cell death and neural activation) previously reported in the newborn brain.

Monocytes and Macrophages in Spondyloarthritis: Functional Roles and Effects of Current Therapies

Spondyloarthritis (SpA) is a family of chronic inflammatory diseases, being the most prevalent ankylosing spondylitis (AS) and psoriatic arthritis (PsA). These diseases share genetic, clinical and immunological features, such as the implication of human leukocyte antigen (HLA) class I molecule 27 (HLA-B27), the inflammation of peripheral, spine and sacroiliac joints and the presence of extra-articular manifestations (psoriasis, anterior uveitis, enthesitis and inflammatory bowel disease). Monocytes and macrophages are essential cells of the innate immune system and are the first line of defence against external agents. In rheumatic diseases including SpA, the frequency and phenotypic and functional characteristics of both cell types are deregulated and are involved in the pathogenesis of these diseases. In fact, monocytes and macrophages play key roles in the inflammatory processes characteristics of SpA. The aim of this review is analysing the characteristics and functional roles of monocytes and macrophages in these diseases, as well as the impact of different current therapies on these cell types.

Pro-and anti-inflammatory effects of glucocorticoid Fluticasone on ovarian and immune functions in commercial-aged laying hens

Ovarian chronic inflammation has been created and extended in the laying hen mainly via increasing laying frequency and microbial infection, especially during the late stage of production period. This study was aimed to evaluate glucocorticoid (GC) Fluticasone as an anti-inflammatory agent on the gene expression of the ovarian pro-and anti-inflammatory mediators (follicular cyclooxygenases COX 1, 2, and cytokines), inflammatory responses of the immune system, ovarian functions (ovulation rate and follicular growths), and hormones in the commercial-aged laying hens. White Leghorn hens aged 92-weeks were used for four weeks to be supplemented by 2 ppm Fluticasone as an optimum dose obtained in a pre-trial base on ovulation rate. As compared to control, Fluticasone resulted in a significant decrease in the mRNA expression of COX-1 and pro-and anti-inflammatory cytokines, and increase in COX-2 mRNA expression and heterophil to lymphocyte ratio (P < 0.001). A significant reduction was observed in the ovulation rate, follicular size (P < 0.001), ovarian hormones, immunoglobulins, body weight, and food consummation (P ≤ 0.05) by administering GC Fluticasone. Although a relative anti-inflammatory improvement was created by Fluticasone in the ovarian condition, the administration of this glucocorticoid resulted in a considerable reduction in ovarian hormones and functions of commercial aged laying hens.

Dexamethasone Inhibits the Pro-Angiogenic Potential of Primary Human Myoblasts

Tissue regeneration depends on the complex processes of angiogenesis, inflammation and wound healing. Regarding muscle tissue, glucocorticoids (GCs) inhibit pro-inflammatory signalling and angiogenesis and lead to muscle atrophy. Our hypothesis is that the synthetic GC dexamethasone (dex) impairs angiogenesis leading to muscle atrophy or inhibited muscle regeneration. Therefore, this study aims to elucidate the effect of dexamethasone on HUVECs under different conditions in mono- and co-culture with myoblasts to evaluate growth behavior and dex impact with regard to muscle atrophy and muscle regeneration. Viability assays, qPCR, immunofluorescence as well as ELISAs were performed on HUVECs, and human primary myoblasts seeded under different culture conditions. Our results show that dex had a higher impact on the tube formation when HUVECs were maintained with VEGF. Gene expression was not influenced by dex and was independent of cells growing in a 2D or 3D matrix. In co-culture CD31 expression was suppressed after incubation with dex and gene expression analysis revealed that dex enhanced expression of myogenic transcription factors, but repressed angiogenic factors. Moreover, dex inhibited the VEGF mediated pro angiogenic effect of myoblasts and inhibited expression of angiogenic inducers in the co-culture model. This is the first study describing a co-culture of human primary myoblast and HUVECs maintained under different conditions. Our results indicate that dex affects angiogenesis via inhibition of VEGF release at least in myoblasts, which could be responsible not only for the development of muscle atrophy after dex administration, but also for inhibition of muscle regeneration after vascular damage.

Glucocorticoids as Regulators of Macrophage-Mediated Tissue Homeostasis

Our immune system has evolved as a complex network of cells and tissues tasked with maintaining host homeostasis. This is evident during the inflammatory responses elicited during a microbial infection or traumatic tissue damage. These responses seek to eliminate foreign material or restore tissue integrity. Even during periods without explicit disturbances, the immune system plays prominent roles in tissue homeostasis. Perhaps one of the most studied cells in this regard is the macrophage. Tissue-resident macrophages are a heterogenous group of sensory cells that respond to a variety of environmental cues and are essential for organ function. Endogenously produced glucocorticoid hormones connect external environmental stress signals with the function of many cell types, producing profound changes in immune cells, including macrophages. Here, we review the current literature which demonstrates specific effects of glucocorticoids in several organ systems. We propose that tissue-resident macrophages, through glucocorticoid signaling, may play an underappreciated role as regulators of organ homeostasis.

Resiniferatoxin promotes adult worm expulsion in Trichinella spiralis-infected rats by Th2 immune response modulation

BACKGROUND

The immune response during T spiralis infection is characterized by an increase in eosinophils and mast cells, as well as Th2 cytokine production, such as interleukin (IL)-4, IL-10 and IL-13, promoting T spiralis expulsion from the host. However, this response damages the host, favouring the parasite survival. In the search for new pharmacological strategies that protect against T spiralis infection, a recent study showed that treatment with resiniferatoxin (RTX) modulates the Th1 cytokines production, reducing muscle parasite burden.

OBJECTIVE

To evaluate the effect of RTX treatment on the Th2 cytokines production, the number of eosinophils, mast cells and the intestinal expulsion of T spiralis.

METHODS

Serum levels of IL-4, IL-10 and IL-13 were quantified by ELISA; the number of eosinophils, mast cells and the adult worms of T spiralis in the small intestine was quantified.

RESULTS

RTX treatment increased serum levels of IL-4, IL-10 and IL-13, and it decreases intestinal eosinophilia, however, favours the mastocytosis, promoting T spiralis intestinal expulsion.

CONCLUSIONS

These findings suggest that RTX is capable to modulate the Th2 immune response, promoting T spiralis expulsion, which contributes to the defence against T spiralis infection, placing the RTX as a potential immunomodulatory drug.

Corticosteroids for COVID-19 Therapy: Potential Implications on Tuberculosis

On 11 March 2020, the World Health Organization announced the Corona Virus Disease-2019 (COVID-19) as a global pandemic, which originated in China. At the host level, COVID-19, caused by the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), affects the respiratory system, with the clinical symptoms ranging from mild to severe or critical illness that often requires hospitalization and oxygen support. There is no specific therapy for COVID-19, as is the case for any common viral disease except drugs to reduce the viral load and alleviate the inflammatory symptoms. Tuberculosis (TB), an infectious disease caused by Mycobacterium tuberculosis (Mtb), also primarily affects the lungs and has clinical signs similar to pulmonary SARS-CoV-2 infection. Active TB is a leading killer among infectious diseases and adds to the burden of the COVID-19 pandemic worldwide. In immunocompetent individuals, primary Mtb infection can also lead to a non-progressive, asymptomatic latency. However, latent Mtb infection (LTBI) can reactivate symptomatic TB disease upon host immune-suppressing conditions. Importantly, the diagnosis and treatment of TB are hampered and admixed with COVID-19 control measures. The US-Center for Disease Control (US-CDC) recommends using antiviral drugs, Remdesivir or corticosteroid (CST), such as dexamethasone either alone or in-combination with specific recommendations for COVID-19 patients requiring hospitalization or oxygen support. However, CSTs can cause immunosuppression, besides their anti-inflammatory properties. The altered host immunity during COVID-19, combined with CST therapy, poses a significant risk for new secondary infections and/or reactivation of existing quiescent infections, such as LTBI. This review highlights CST therapy recommendations for COVID-19, various types and mechanisms of action of CSTs, the deadly combination of two respiratory infectious diseases COVID-19 and TB. It also discusses the importance of screening for LTBI to prevent TB reactivation during corticosteroid therapy for COVID-19.

Regulation of Gut Microbiota Disrupts the Glucocorticoid Receptor Pathway and Inflammation-related Pathways in the Mouse Hippocampus

An increasing number of studies have recently indicated the important effects of gut microbes on various functions of the central nervous system. However, the underlying mechanisms by which gut microbiota regulate brain functions and behavioral phenotypes remain largely unknown. We therefore used isobaric tags for relative and absolute quantitation (iTRAQ)-based quantitative proteomic analysis to obtain proteomic profiles of the hippocampus in germ-free (GF), colonized GF, and specific pathogen-free (SPF) mice. We then integrated the resulting proteomic data with previously reported mRNA microarray data, to further explore the effects of gut microbes on host brain functions. We identified that 61 proteins were upregulated and 242 proteins were downregulated in GF mice compared with SPF mice. Of these, 124 proteins were significantly restored following gut microbiota colonization. Bioinformatic analysis of these significant proteins indicated that the glucocorticoid receptor signaling pathway and inflammation-related pathways were the most enriched disrupted pathways. This study provides new insights into the pathological mechanisms of gut microbiota-regulated diseases.

The Role of Glucocorticoids in the Management of COVID-19

Coronavirus disease 2019 (COVID-19), caused by an infection with the novel coronavirus SARS-CoV-2, has resulted in a global pandemic and poses an emergency to public health systems worldwide. COVID-19 is highly infectious and is characterized by an acute respiratory illness that varies from mild flu-like symptoms to the life-threatening acute respiratory distress syndrome (ARDS). As such, there is an urgent need for the development of new therapeutic strategies, which combat the high mortality in severely ill COVID-19 patients. Glucocorticoids are a frontline treatment for a diverse range of inflammatory diseases. Due to their immunosuppressive functions, the use of glucocorticoids in the treatment of COVID-19 patients was initially regarded with caution. However, recent studies concluded that the initiation of systemic glucocorticoids in patients suffering from severe and critical COVID-19 is associated with lower mortality. Herein we review the anti-inflammatory effects of glucocorticoids and discuss emerging issues in their clinical use in the context of COVID-19.

Inhibition of adjuvant-induced TAM receptors potentiates cancer vaccine immunogenicity and therapeutic efficacy

Analyzing immunomodulatory elements operating during antitumor vaccination in prostate cancer patients and murine models we identified IL-10-producing DC as a subset with poorer immunogenicity and clinical efficacy. Inhibitory TAM receptors MER and AXL were upregulated on murine IL-10⁺ DC. Thus, we analyzed conditions inducing these molecules and the potential benefit of their blockade during vaccination. MER and AXL upregulation was more efficiently induced by a vaccine containing Imiquimod than by a poly(I:C)-containing vaccine. Interestingly, MER expression was found on monocyte-derived DC, and was dependent on IL-10. TAM blockade improved Imiquimod-induced DC activation in vitro and in vivo, resulting in increased vaccine-induced T-cell responses, which were further reinforced by concomitant IL-10 inhibition. In different tumor models, a triple therapy (including vaccination, TAM inhibition and IL-10 blockade) provided the strongest therapeutic effect, associated with enhanced T-cell immunity and enhanced CD8⁺ T cell tumor infiltration. Finally, MER levels in DC used for vaccination in cancer patients correlated with IL-10 expression, showing an inverse association with vaccine-induced clinical response. These results suggest that TAM receptors upregulated during vaccination may constitute an additional target in combinatorial therapeutic vaccination strategies.

New insights into the cell- and tissue-specificity of glucocorticoid actions

Glucocorticoids (GCs) are endogenous hormones that are crucial for the homeostasis of the organism and adaptation to the external environment. Because of their anti-inflammatory effects, synthetic GCs are also extensively used in clinical practice. However, almost all cells in the body are sensitive to GC regulation. As a result, these mediators have pleiotropic effects, which may be undesirable or detrimental to human health. Here, we summarize the recent findings that contribute to deciphering the molecular mechanisms downstream of glucocorticoid receptor activation. We also discuss the complex role of GCs in infectious diseases such as sepsis and COVID-19, in which the balance between pathogen elimination and protection against excessive inflammation and immunopathology needs to be tightly regulated. An understanding of the cell type- and context-specific actions of GCs from the molecular to the organismal level would help to optimize their therapeutic use.

Preferential inhibition of adaptive immune system dynamics by glucocorticoids in patients after acute surgical trauma

Glucocorticoids (GC) are a controversial yet commonly used intervention in the clinical management of acute inflammatory conditions, including sepsis or traumatic injury. In the context of major trauma such as surgery, concerns have been raised regarding adverse effects from GC, thereby necessitating a better understanding of how GCs modulate the immune response. Here we report the results of a randomized controlled trial (NCT02542592) in which we employ a high-dimensional mass cytometry approach to characterize innate and adaptive cell signaling dynamics after a major surgery (primary outcome) in patients treated with placebo or methylprednisolone (MP). A robust, unsupervised bootstrap clustering of immune cell subsets coupled with random forest analysis shows profound (AUC = 0.92, p-value = 3.16E-8) MP-induced alterations of immune cell signaling trajectories, particularly in the adaptive compartments. By contrast, key innate signaling responses previously associated with pain and functional recovery after surgery, including STAT3 and CREB phosphorylation, are not affected by MP. These results imply cell-specific and pathway-specific effects of GCs, and also prompt future studies to examine GCs' effects on clinical outcomes likely dependent on functional adaptive immune responses.

Evidence for a More Disrupted Immune-Endocrine Relation and Cortisol Immunologic Influences in the Context of Tuberculosis and Type 2 Diabetes Comorbidity

Pulmonary tuberculosis (PTB), caused by Mycobacterium tuberculosis (Mtb), is a major health problem worldwide, further aggravated by the convergence of type 2 diabetes mellitus (DM) which constitutes an important risk factor for TB development. The worse scenario of patients with PTB and DM may be partly related to a more unbalanced defensive response. As such, newly diagnosed PTB patients with DM (TB+DM, n = 11) or not (TB, n = 21), as well as DM (n = 18) patients and pair matched controls (Co, n = 22), were investigated for the circulating immuno-endocrine-metabolic profile (ELISA), along with studies in peripheral blood mononuclear cells (PBMC) analyzing transcript expression (RT-qPCR) of mediators involved in glucocorticoid functionality. Given the hyperglycemic/hypercortisolemic scenario of TB+DM patients, PBMC were also exposed to stress-related cortisol concentrations (0.1 and 1 μM) and supraphysiologic glucose doses (10, 20, and 40 mM) and assessed for the specific response against Mtb stimulation (lymphoproliferation, -thymidine incorporation-, and cytokine production -bead-cytometry). All TB patients displayed increased plasma amounts of cortisol, growth hormone -hGH-, and proinflammatory mediators. In turn, TB+DM showed even higher levels of interferon gamma -IFN-γ- and hGH (vs. TB), or IL-6, C reactive protein, cortisol and hGH (vs. DM). Both DM groups had equally augmented values of IL-10. All TB patients showed decreased dehydroepiandrosterone- sulfate concentrations, even more in TB+DM cases. Leptin was also decreased in both TB cases, particularly in the TB group, revealing a lower body mass index, as well. Unlike PBMC from TB cases showing a decreased relationship between the glucocorticoids receptor (GR) isoforms (GRα/GRβ; functional isoform/negative isoform), cells from TB+DM patients had no changes in this regard, along with an increased expression of 11-beta hydroxysteroid dehydrogenase type-1, the enzyme facilitating intracellular cortisone to cortisol conversion. TB+DM patients also showed an increased Mtb antigen-driven lymphoproliferation. Compared to TB, DM and HCo counterparts, PBMC from TB+DM patients had a biased Th1 response to Mtb stimulation (increased IL-2 and IFN-γ production), even when exposed to inhibitory cortisol doses. TB+DM patients show a more unbalanced immuno-endocrine relationship, respect the non-diabetic counterparts, with a relative deficiency of cortisol immunomodulatory influences, despite their more favorable microenvironment for cortisol-mediated immune effects.

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.

Impaired immunoregulatory network of the CD4 T lymphocytes in refractory asthma

BACKGROUND

The immunopathogenesis of severe asthma has been associated with an inefficient regulatory response. There are a few studies about the CD4 T cells profile among individuals with severe asthma refractory to treatment.

OBJECTIVE

To evaluate the CD4 T lymphocyte profile from individuals with severe asthma according to their response to treatment, relating to their atopy status and age of asthma onset.

METHODS

We evaluated nineteen individuals with severe asthma refractory to treatment (SAR), 21 with well-controlled or partly controlled severe asthma (CSA) and 23 with mild-to-moderate asthma (MMA). Lymphocytes were obtained from PBMC, and the frequency of expression of different molecules in this population was assessed using the flow cytometry.

RESULTS

We observed the frequency of CD4⁺ IFN-γ⁺ T cells was higher in atopic individuals with SAR than with CSA. In addition, among the atopic and early-onset asthma (EOA), the frequency of CD4⁺ CTLA-4⁺ T cells was lower in the SAR group than the CSA group. In relation to non-atopic and late-onset asthma (LOA) phenotypes, we noted the frequency of CD4⁺ FoxP3⁺ T cells was lower in individuals with SAR than with CSA. We also observed among the LOA patients, the frequency of CD4⁺ TGF-β⁺ T cells was decreased in SAR group than the in CSA group.

CONCLUSION AND CLINICAL RELEVANCE

Our data suggest that refractoriness to treatment in asthma is associated with a lower expression of distinct regulatory molecules by CD4 T cells between those who are atopic and have EOA and those who are non-atopic and have LOA. Thus, these results may contribute to the identification of new regulatory strategies to treat asthma according to their phenotypes.

Immune regulation by glucocorticoids can be linked to cell type-dependent transcriptional responses

A functional genomics approach uncovers previously undescribed cell type–dependent responses that can be linked to the immunoregulatory actions of glucocorticoids in humans.

Glucocorticoids remain the most widely used immunosuppressive and anti-inflammatory drugs, yet substantial gaps exist in our understanding of glucocorticoid-mediated immunoregulation. To address this, we generated a pathway-level map of the transcriptional effects of glucocorticoids on nine primary human cell types. This analysis revealed that the response to glucocorticoids is highly cell type dependent, in terms of the individual genes and pathways affected, as well as the magnitude and direction of transcriptional regulation. Based on these data and given their importance in autoimmunity, we conducted functional studies with B cells. We found that glucocorticoids impair upstream B cell receptor and Toll-like receptor 7 signaling, reduce transcriptional output from the three immunoglobulin loci, and promote significant up-regulation of the genes encoding the immunomodulatory cytokine IL-10 and the terminal-differentiation factor BLIMP-1. These findings provide new mechanistic understanding of glucocorticoid action and emphasize the multifactorial, cell-specific effects of these drugs, with potential implications for designing more selective immunoregulatory therapies.

Early-life adversity programs long-term cytokine and microglia expression within the HPA axis in female Japanese quail

Stress exposure during pre and post-natal development can have persistent and often dysfunctional effects on several physiological systems, including immune function, affecting the ability to combat infection. The neuro-immune response is inextricably linked to the action of the Hypothalamic Pituitary Adrenal (HPA) axis. Cytokines released from neuro-immune cells, including microglia, activate the HPA axis while glucocorticoids in turn regulate cytokine release from microglia. Because of the close links between these two physiological systems, coupled with potential for persistent changes to HPA axis activity following developmental stress, components of the neuro-immune system could be targets for developmental programming. However, little is known of any programming effects of developmental stress on neuro-immune function. We investigated whether developmental stress exposure via elevated pre-natal corticosterone (CORT) or post-natal unpredictable food availability, had long-term effects on pro (IL-1β) and anti-inflammatory (IL-10) cytokine and microglia-dependent gene (CSF1R) expression within HPA axis tissues in a precocial bird, the Japanese quail (Coturnix japonica). Following post-natal stress, we observed increased IL-1β expression in the pituitary gland, reduced IL-10 expression in the amygdala and hypothalamus and reduced CSF1R expression within the hypothalamus and pituitary gland. Post-natal stress disrupted the ratio of IL-1β:IL-10 expression within the hippocampus and hypothalamus. Pre-natal stress only increased IL-1β expression in the pituitary gland. We found no evidence for interactive or cumulative effects across life stages on basal cytokine and glia expression in adulthood. We show that post-natal stress may have a larger impact than elevated pre-natal CORT on basal immunity in HPA axis specific brain regions, with changes in cytokine homeostasis and microglia abundance. These results provide evidence for post-natal programming of a pro-inflammatory neuro-immune phenotype at the expense of reduced microglia, which could have implications for CNS health and subsequent neuro-immune responses.

Differing efficacies of autologous platelet-rich plasma treatment in reducing pain following rotator-cuff injury in a single patient

Rotator-cuff tears (RCTs) are typically associated with chronic pain. The most common treatment for reducing pain is the injection of cortisone into the injury site. An alternative and increasingly used technique is the injection of autologous platelet-rich plasma (PRP). A limitation of cortisone is its pain relief is short-lived, while PRP has the limitation of providing pain relief to only about 50% of patients, making its efficacy questioned, although when it is effective, its efficacy is longer than cortisone. Little is known about what accounts for these limitations. This paper presents results from a patient with RCTs causing excruciating pain who received an injection of PRP into that shoulder resulting in complete pain elimination that was ongoing at 2 years and 2 months. When 7-month severe posttrauma pain associated with the RCT developed in the contralateral shoulder, PRP prepared the same way and injected by the same person who performed the first injection provided no pain relief. However, a subsequent single cortisone injection resulted in complete pain elimination, which was ongoing at >15 months. These observations indicate that PRP can have inconsistent effects in reducing pain, not only between patients but also within the same patient. Further, although the pain relief induced by cortisone is normally not long-lasting, when given following a PRP injection, it can induce complete pain relief lasting >15 months. This paper discusses possible reasons for the variability in PRP efficacy on pain relief and addresses the possibility that when administered together, PRP and cortisone may act in a complementary manner, leading to significantly greater and longer-lasting pain relief.

Enhancing Allergen-Presentation Platforms for Sublingual Immunotherapy

Sublingual immunotherapy (SLIT) relies on high doses of allergens to treat patients with type I allergies. Although SLIT is commonly performed without any adjuvant or delivery system, allergen(s) could be further formulated with allergen-presentation platforms to better target oral dendritic cells eliciting regulatory immune responses. Improving the availability of allergens to the immune system should enhance SLIT efficacy, while allowing to decrease allergen dosing. Herein, we present an overview of adjuvants and vector systems that have been, or could be, considered as candidate allergen-presentation platforms for the sublingual route. Such platforms encompass adjuvants capable of stimulating allergen-specific T_H1 and/or regulatory CD4⁺ T-cell responses, including 1,25-dihydroxy vitamin D₃, glucocorticoids, Toll-like receptor ligands as well as selected bacterial probiotic strains. A limiting factor for SLIT efficacy is the number of dendritic cells capturing the allergens in the upper layers of oral tissues. Thus, adsorption or encapsulation of the allergen(s) within mucoadhesive particulate vector (or delivery) systems also has the potential to significantly enhance SLIT efficacy due to a facilitated allergen uptake by tolerogenic oral dendritic cells.

Circulating microparticle subpopulations in systemic lupus erythematosus are affected by disease activity

BACKGROUND

Immune cells under chronic inflammation shed microparticles (MPs) that could fuel the inflammatory responses and atherosclerosis typically presented in systemic lupus erythematosus (SLE). This study analyzes total and subset-specific MPs from SLE patients and their possible influence on clinical features, leukocyte activation and serum cytokines.

METHODS

Total MPs and those derived from platelets, endothelial cells, monocytes, granulocytes and T-cells were quantified in plasma of 106 SLE patients and 33 healthy controls by flow cytometry. MP amounts were analyzed according to clinical manifestations, blood leukocyte populations and circulating cytokines (IFNα, TNFα, IL-10, BLyS, IL-17, IL-1β, CXCL10, CCL-2, CCL3, leptin). Finally, the in vitro effect of SLE-isolated MPs on the leukocyte activation status was analyzed.

RESULTS

Total circulating MPs in SLE patients were related to increased disease duration and the presence of cardiovascular disease. Furthermore, patients displayed increased counts of MPs from platelets, monocytes and T-lymphocytes, especially in SLE patients with disease activity or with TNFα^high-profile. Accordingly, MPs were associated with increased expression of activation markers in blood T-cells and monocytes. Finally, analyses propose a role of glucocorticoids in MPs generation and leukocyte activation since both fresh and cultured T-cells under this treatment presented higher IL-10 and CD25 production.

CONCLUSIONS

The altered profile of subset-specific SLE-MPs was influenced by the disease activity and altered status of leukocyte native cells, also associated with a TNFα^high-profile.

TRANSLATIONAL RESULTS

SLE patients, especially those with disease activity, displayed increased counts of MPs derived from platelets, monocytes and T-lymphocytes, which were more frequently found in TNFα^high-type patients. The origin of such SLE-MP subsets seems to be related to the over-activated status of T-cells and monocytes characteristic of these patients. Ex vivo and in vitro analyses propose a role of glucocorticoids in the generation of circulating MPs and leukocyte activation in SLE patients.

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.

Elevated Bioactivity of the Tolerogenic Cytokines, Interleukin-10 and Transforming Growth Factor-β, in the Blood of Acutely Malnourished Weanling Mice

The main objective of this investigation was to determine the influence of acute deficits of protein and energy on the blood levels of interleukin-10 (IL-10) and transforming growth factor-β (TGF-β), physiologically the main anti-inflammatory and tolerogenic cytokines. In four 14-day experiments, male and female C57BL/6J mice, initially 19 days old, consumed a complete purified diet either ad libitum or in restricted daily quantities, or had free access to an isocaloric purified low-protein diet. A zero-time control group (19 days old) was included. In the first two experiments, serum IL-10 levels were assessed by sandwich enzyme-linked immunosorbent assay (ELISA) and bioassay. The mean serum IL-10 bioactivities were higher (P ≤ 0.05) in both malnourished groups (low-protein and restricted intake: 15.8 and 12.2 ng/ml, respectively) than in the zero-time and age-matched control groups (6.3 and 7.3 ng/ml, respectively), whereas serum IL-10 immunoactivity was high only in the restricted intake group (e.g., second experiment: 17.0 pg/ml vs. 5.4, 3.7, and 3.1 pg/ml in the zero-time control, age-matched control and low-protein group, respectively). The third and fourth experiments centered on plasma TGF-β immunoactivity (sandwich ELISA) and bioactivity, respectively. The ELISA revealed a high mean plasma TGF-β1 level (P < 0.05) in the low-protein group only, but TGF-β bioactivity (β1 isoform, although 15% β2 in the restricted intake group) was high in both malnourished groups (8.7 and 9.3 ng/ml in the low-protein and restricted groups, respectively) relative to the age-matched control group (0.5 ng/ml). Thus, metabolically distinct weanling systems mimicking marasmus and incipient kwashiorkor both exhibit a blood cytokine profile that points to a tolerogenic microenvironment within immune response compartments. A model emerges in which malnutrition-associated immune competence, at least in advanced weight loss, centers on cytokine-mediated peripheral tolerance that reduces the risk of catabolically induced autoimmune disease, but this is at the cost of attenuated responsiveness to infectious agents.

Medroxyprogesterone acetate differentially regulates interleukin (IL)-12 and IL-10 in a human ectocervical epithelial cell line in a glucocorticoid receptor (GR)-dependent manner

Medroxyprogesterone acetate (MPA), designed to mimic the actions of the endogenous hormone progesterone (P4), is extensively used by women as a contraceptive and in hormone replacement therapy. However, little is known about the steroid receptor-mediated molecular mechanisms of action of MPA in the female genital tract. In this study, we investigated the regulation of the pro-inflammatory cytokine, interleukin (IL)-12, and the anti-inflammatory cytokine IL-10, by MPA versus P4, in an in vitro cell culture model of the female ectocervical environment. This study shows that P4 and MPA significantly increase the expression of the IL-12p40 and IL-12p35 genes, whereas IL-10 gene expression is suppressed in a dose-dependent manner. Moreover, these effects were abrogated when reducing the glucocorticoid receptor (GR) levels with siRNA. Using a combination of chromatin immunoprecipitation (ChIP), siRNA, and re-ChIP assays, we show that recruitment of the P4- and MPA-bound GR to the IL-12p40 promoter requires CCAAT enhancer-binding protein (C/EBP)-β and nuclear factor κB (NFκB), although recruitment to the IL-10 promoter requires signal transducer and activator of transcription (STAT)-3. These results suggest that both P4 and MPA may modulate inflammation in the ectocervix via this genomic mechanism.

Stress, ageing and their influence on functional, cellular and molecular aspects of the immune system

The immune response is essential for keeping an organism healthy and for defending it from different types of pathogens. It is a complex system that consists of a large number of components performing different functions. The adequate and controlled interaction between these components is necessary for a robust and strong immune response. There are, however, many factors that interfere with the way the immune response functions. Stress and ageing now consistently appear in the literature as factors that act upon the immune system in the way that is often damaging. This review focuses on the role of stress and ageing in altering the robustness of the immune response first separately, and then simultaneously, discussing the effects that emerge from their interplay. The special focus is on the psychological stress and the impact that it has at different levels, from the whole system to the individual molecules, resulting in consequences for physical health.

Chronic exposure to glucocorticoids shapes gene expression and modulates innate and adaptive activation pathways in macrophages with distinct changes in leukocyte attraction

Glucocorticoids (GCs) have been used for more than 50 y as immunosuppressive drugs, yet their efficacy in macrophage-dominated disorders, such as chronic obstructive pulmonary disease, is debated. Little is known how long-term GC treatment affects macrophage responses in inflammatory conditions. In this study, we compared the transcriptome of human macrophages, matured in the presence or absence of fluticasone propionate (FP), and their ability to initiate or sustain classical activation, mimicked using acute LPS and chronic IFN-γ stimulation, respectively. We identified macrophage gene expression networks, modulated by FP long-term exposure, and specific patterns of IFN-γ- and LPS-induced genes that were resistant, inhibited, or exacerbated by FP. Results suggest that long-term treatment with GCs weakens adaptive immune signature components of IFN-γ and LPS gene profiles by downmodulating MHC class II and costimulatory molecules, but strengthens innate signature components by maintaining and increasing expression of chemokines involved in phagocyte attraction. In a mouse model of chronic obstructive pulmonary disease, GC treatment induced higher chemokine levels, and this correlated with enhanced recruitment of leukocytes. Thus, GCs do not generally suppress macrophage effector functions, but they cause a shift in the innate-adaptive balance of the immune response, with distinct changes in the chemokine-chemokine receptor network.

Cellular and urinary microRNA alterations in NZB/W mice with hydroxychloroquine or prednisone treatment

Determining alterations to disease-associated miRNAs induced by specific therapeutics may allow the use of tailored therapy in lupus. We determined miRNA alterations in female NZB/W lupus mice treated with hydroxychloroquine (HCQ) or prednisone (PRED) for 12 weeks beginning at 24 weeks-of-age. B cell, PBMC, and urinary miR-let-7a expression were decreased with HCQ or PRED treatment. HCQ or PRED treatment reduced miR-21 expression in mesangial cells, T cells, pDCs, PBMCs, and the urine. MiR-146a expression was reduced in mesangial cells with HCQ treatment and in pDCs with HCQ or PRED treatment. PRED treatment increased miR-155 expression in mesangial, B, and T cells and PBMCs yet decreased miR-155 expression in pDCs and the urine. In vitro studies confirmed that HCQ or PRED's anti-inflammatory actions are dependent on their ability to inhibit miRNA expression. Our studies indicate that lupus therapeutics may work, in part, by altering the expression of disease-associated miRNAs.

It takes two to tango: dimerisation of glucocorticoid receptor and its anti-inflammatory functions

For a number of years, there has been a widespread view that the adverse side-effects of prolonged glucocorticoid (GC) treatment are a result of glucocorticoid receptor (GR)-mediated gene activation, whilst the beneficial anti-inflammatory effects result from GR-mediated 'transrepression'. Since the introduction of the dimerisation-deficient GR mutant, GR(dim), was apparently unable to activate gene transcription, yet still able to repress pro-inflammatory gene transcription, the search for novel GR modulators has centred on the separation of gene activation from repression by prevention of GR dimerisation. However, recent work has questioned the conclusions drawn from these early GR(dim) studies, with evidence that GR(dim) mutants not only activate gene transcription, but that, in direct contradiction to the initial GR(dim) work, are also capable of forming dimers. This review of the current literature highlights the versatility of the GR in forming homodimer interactions, as well as the ability to bind to alternate nuclear receptors, and investigates the potential implications such varying GR dimer conformations may have for the design of GR ligands with a safer side effect profile.

The anti-inflammatory and immunosuppressive effects of glucocorticoids, recent developments and mechanistic insights

Since the discovery of glucocorticoids in the 1940s and the recognition of their anti-inflammatory effects, they have been amongst the most widely used and effective treatments to control inflammatory and autoimmune diseases. However, their clinical efficacy is compromised by the metabolic effects of long-term treatment, which include osteoporosis, hypertension, dyslipidaemia and insulin resistance/type 2 diabetes mellitus. In recent years, a great deal of effort has been invested in identifying compounds that separate the beneficial anti-inflammatory effects from the adverse metabolic effects of glucocorticoids, with limited effect. It is clear that for these efforts to be effective, a greater understanding is required of the mechanisms by which glucocorticoids exert their anti-inflammatory and immunosuppressive actions. Recent research is shedding new light on some of these mechanisms and has produced some surprising new findings. Some of these recent developments are reviewed here.

Banding or Burdizzo castration and carprofen administration on peripheral leukocyte inflammatory cytokine transcripts

The objective was to investigate if Banding or Burdizzo castration of bulls would alter the gene expression profile of a range of peripheral leukocyte inflammatory cytokines (IL-1, IL-6, IL-8, IL-10, interferon-γ and tumor necrosis factor-α) and to determine if the administration of carprofen (C) before castration would affect the expression of these genes. Thirty Holstein-Friesian bulls (5.5 months; Mean 191±(SEM) 3.7 kg) were blocked by weight and randomly assigned to one of five treatments: (1) untreated control (CON); (2) Banding castration at 0 min (BAND); (3) BAND following an i.v. injection of 1.4 mg/kg BW of carprofen (C) at -20 min (BAND+C); (4) Burdizzo castration at 0 min (BURD); or (5) BURD following 1.4 mg/kg BW of carprofen at -20 min (BURD+C). Blood samples were collected at 1 h before castration and 6, 24 and 48 h post-castration for routine hematology and quantitative real-time PCR analysis of cytokine gene expression analysis. Generally, there were no differences (P>0.05) among treatment groups in hematological variables following castration. Cortisol concentrations were unchanged throughout the experimental period in CON bulls. BURD animals had greater cortisol concentrations than BAND and CON animals at 6 h post treatment. Transitory effects were observed only in the expression of IL-6 and TNF-α. The relative expression of IL-6 was greater in the BURD than in the BAND treatment (P<0.05) at 24 h post-castration and was greater in the BURD+C group than in the BURD group (P<0.05) at 48 h. The relative expression of TNF-α was greater in BAND than in the BURD group (P<0.05) at 48 h. In conclusion, these findings indicate that Banding or Burdizzo castration did not have any major effect on peripheral leukocyte inflammatory cytokine gene expression; Banding castration caused a greater pro-inflammatory cytokine gene expression reaction than Burdizzo castration and carprofen administration can affect IL-6 gene expression levels in BURD castrated animals.

Interleukin-10 promoter polymorphisms in myasthenia gravis

Interleukin 10 (IL-10) is secreted by several hemopoietic cells and suppresses the Th1 mediated immune response, while stimulating B cell differentiation and the humoral immune response. IL-10 expression in Con A-stimulated peripheral blood mononuclear cells is related to three polymorphisms in the promoter region of the IL-10 gene; G/A at position -1082, T/C at position -819 and A/C at position -592. We analyzed the distribution of these IL-10 polymorphisms in 64 MG patients and 87 healthy blood donors to determine any influence on MG susceptibility. MG patients had a significantly higher frequency of the ACC/ACC haplotype (12.5% vs 3.4% in controls), as had the subgroups with late onset MG and thymomatous MG (20.0% and 21.4%, respectively). Early onset MG patients had a high frequency of the ATA/ATA haplotype (19.2% vs 3.4% in controls). Titin Ab-positive MG patients had high ACC/ACC (20.0%). This study indicates a direct link between IL-10 and MG pathogenesis, although the complex role of this multi-faceted cytokine in vivo is as yet not fully elucidated.

Increased expression of FcgammaRI/CD64 on circulating monocytes parallels ongoing inflammation and nephritis in lupus

Introduction

The high-affinity receptor for IgG Fcγ/CD64 is critical for the development of lupus nephritis (LN). Cross-linking Fc receptor on recruited monocytes by IgG-containing immune complexes is a key step in immune-complex-mediated nephritis in systemic lupus erythematosus (SLE). The goal of this study was to determine whether expression of Fc receptor (FcγR) I on circulating monocytes is associated with systemic inflammation and renal disease in SLE patients.

Methods

We studied 205 SLE patients (132 with LN and 73 without LN) along with 74 healthy control individuals. Surface expression of CD14 (monocytes), FcγRI/CD64, FcγRII/CD32, and FcγRIII/CD16 was evaluated by flow cytometry. Monocyte function was assessed by determining the migratory capacity and the ability to produce CCL2 (monocyte chemotractic protein 1). High-sensitivity C-reactive protein, C3 and C4 were measured by nephelometry.

Results

There was little difference in the expression of FcγRIII/CD16 or FcγRIII/CD32 on circulating monocytes between patients with SLE and control individuals. In contrast, FcγRI/CD64 expression was significantly higher in SLE patients and even higher in patients with LN. FcγRI/CD64 expression was positively associated with serum creatinine and indicators of systemic inflammation. Monocytes from patients with high FcγRI/CD64 expression also exhibited increased chemotaxis and capacity to produce monocyte chemotractic protein 1.

Conclusions

Increased FcγRI/CD64 expression on circulating monocytes parallels systemic inflammation and renal disease in SLE patients. We propose that circulating monocytes activated by immune complexes and/or proinflammatory mediators upregulate surface expression of FcγRI/CD64 in SLE. The enhanced chemotactic and inflammatory potential of the activated monocytes may participate in a vicious cycle of immune cell recruitment and renal injury in SLE.

Handbook of experimental pharmacology "dendritic cells": the use of dexamethasone in the induction of tolerogenic DCs

Dendritic cells (DCs) have a central role in immune regulation, ranging from tolerance induction to the induction of specific immune responses. DCs serve as an essential link between innate and adaptive immunity. This broad range of powerful immune stimulatory as well as regulatory functions has made DCs as targets for vaccine development strategies. One approach to promote the tolerogenicity of DCs is to suppress their maturation by pharmacological agents, including glucocorticoids (GCs). In the present chapter we will review GCs used in vitro with cultured DCs, applied in vivo, or used to generate tolerogenic DCs for cellular therapy.

Glucocorticoids induce an activated, anti-inflammatory monocyte subset in mice that resembles myeloid-derived suppressor cells

Glucocorticoids (GC) are still the most widely used immunosuppressive agents in clinical medicine. Surprisingly, little is known about the mechanisms of GC action on monocytes, although these cells exert pro- and anti-inflammatory effects. We have shown recently that GC induce a specific monocyte phenotype with anti-inflammatory properties in humans. We now investigated whether this also applies for the murine system and how this subset would relate to recently defined murine subtypes. After treatment with dexamethasone for 48 h, monocytes up-regulated scavenger receptor CD163 and Gr-1, down-regulated CX(3)CR1, and shared with human GC-treated monocytes functional features such as low adhesiveness but high migratory capacity. They specifically up-regulated anti-inflammatory IL-10, but not TGF-beta, and in contrast to their human counterparts, they down-regulated IL-6. Although GC-induced monocytes down-regulated CX(3)CR1, a distinctive marker for classical/proinflammatory human and murine monocytes (CX(3)CR1(lo)CCR2(+)Ly6C(hi)), they differed from this physiologically occurring subset, as they remained Ly6C(med) and unactivated (CD62 ligand(++)). In addition to their immunosuppressive effects, they were CD11b(+)Gr-1(+) and expressed the IL-4Ralpha chain (CD124), a recently described, signature molecule of tumor-induced myeloid-derived suppressor cells (MDSC). We therefore generated murine MDSC in B16 melanoma-bearing mice and indeed found parallel up-regulation of CD11b(+)Gr-1(+) and CD124 on GC-induced monocytes and MDSC. These data allow us to speculate that the GC-induced subtype shares with inflammatory monocytes the ability to migrate quickly into inflamed tissue, where they, however, exert anti-inflammatory effects and that similarities between GC-induced monocytes and MDSC may be involved in progression of some tumors observed in patients chronically treated with GC.

Increased susceptibility of annexin-A1 null mice to nociceptive pain is indicative of a spinal antinociceptive action of annexin-A1

BACKGROUND AND PURPOSE

Annexin-A1 (ANXA1), a glucocorticoid-regulated protein, mediates several of the anti-inflammatory actions of the glucocorticoids. Previous studies demonstrated that ANXA1 is involved in pain modulation. The current study, using ANXA1 knockout mice (ANXA1-/-), is aimed at addressing the site and mechanism of the modulatory action of ANXA1 as well as possible involvement of ANXA1 in mediating the analgesic action of glucocorticoids.

EXPERIMENTAL APPROACH

The acetic acid-induced writhing response was performed in ANXA1-/- and wild-type (ANXA1+/+) mice with spinal and brain levels of prostaglandin E2 (PGE2) examined in both genotypes. The effect of the ANXA1 peptomimetic Ac2-26 as well as methylprednisolone on the writhing response and on spinal cord PGE2 of ANXA1+/+ and ANXA1-/- was compared. The expression of proteins involved in PGE2 synthesis, cytosolic phospholipase A2 (cPLA2) and cyclooxygenases (COXs), in the spinal cord of ANXA1+/+ and ANXA1-/- was also compared.

KEY RESULTS

ANXA1-/- mice exhibited a significantly greater writhing response and increased spinal cord levels of PGE2 compared with ANXA1+/+ mice. Ac2-26 produced analgesia and reduced spinal PGE2 levels in ANXA1+/+ and ANXA1-/- mice, whereas methylprednisolone reduced the writhing response and spinal PGE2 levels in ANXA1+/+, but not in ANXA1-/- mice. The expression of cPLA2, COX-1, COX-2 and COX-3 in spinal cord tissues was upregulated in ANXA1-/-compared with ANXA1+/+.

CONCLUSIONS AND IMPLICATIONS

We conclude that ANXA1 protein modulates nociceptive processing at the spinal level, by reducing synthesis of PGE2 by modulating cPLA2 and/or COX activity. The analgesic activity of methylprednisolone is mediated by spinal ANXA1.