Molecular mechanisms of glucocorticoid action and selective glucocorticoid receptor agonists

Injectable Anti-inflammatory Nanofiber Hydrogel to Achieve Systemic Immunotherapy Post Local Administration

Despite the great promise achieved by immune checkpoint blockade (ICB) therapy in harnessing the immune system to combat different tumors, limitations such as low objective response rates and adverse effects remain to be resolved. Here, an anti-inflammatory nanofiber hydrogel self-assembled by steroid drugs is developed for local delivery of antiprogrammed cell death protein ligand 1 (αPDL1). Interestingly, on the one hand this carrier-free system based on steroid drugs can reprogram the pro-tumoral immunosuppressive tumor microenvironment (TME) to antitumoral TME; on the other hand, it would serve as a reservoir for sustained release of αPDL1 so as to synergistically boost the immune system. By local injection of such αPDL1-loaded hydrogel, effective therapeutic effects were observed in inhibiting both local tumors and abscopal tumors without any treatment. This work presents a unique hydrogel-based delivery system using clinically approved drugs, showing promise in improving the objective response rate of ICB therapy and minimizing its systemic toxicity.

Use of glucocorticoids in the management of immunotherapy-related adverse effects

Immune checkpoint inhibitors (ICIs) activate host antitumor immunity to kill tumor cells. However, ICI therapy may be accompanied by a series of immunotherapy‐related adverse effects (irAEs) caused by activated autoreactive T cells. Glucocorticoids are the mainstream therapy for irAEs. However, the usage, dosage and course of treatment of irAEs with glucocorticoids differs from those used in classic autoimmune diseases. Furthermore, the long‐term use of large doses of glucocorticoids may cause serious adverse effects. In this article, the mechanism, dosage forms, adverse effects and management of glucocorticoids are described in detail, providing references and suggestions for oncologists to use glucocorticoids in the treatment of irAEs.

Glucocorticoids are the mainstream therapy for irAEs. We described the mechanism, dosage forms, adverse effects and management of glucocorticoids. We aimed to provide references and suggestions for oncologists to use glucocorticoids in the proper treatment of irAEs.

Intestinal Stem Cell Niche Defects Result in Impaired 3D Organoid Formation in Mouse Models of Crohn's Disease-like Ileitis

Intestinal epithelial barrier dysfunction is a risk factor in the pathogenesis of Crohn’s disease (CD); however, no corrective FDA-approved therapies exist. We used an enteroid (EnO)-based system in two murine models of experimental CD, SAMP1/YitFc (SAMP) and TNF^ΔARE/+ (TNF). While severely inflamed SAMP mice do not generate EnOs, “inflammation-free” SAMP mice form EnO structures with impaired morphology and reduced intestinal stem cell (ISC) and Paneth cell viability. We validated these findings in TNF mice concluding that inflammation in intestinal tissues impedes EnO generation and suppressing inflammation by steroid administration partially rescues impaired formation in SAMP mice. We generated the first high-resolution transcriptional profile of the SAMP ISC niche demonstrating that alterations in multiple key pathways contribute to niche defect and targeting them may partially rescue the phenotype. Furthermore, we correlated the defects in formation and the rescue of EnO formation to reduced viability of ISCs and Paneth cells.

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Enteroid (EnO) formation is impaired in inflammation-free SAMP mice

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SAMP EnOs maintain impaired functions ex vivo recapitulating epithelial CD defect

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Inflammation impedes EnO formation, which is partially restored by steroid treatment

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Reduced number of viable intestinal stem and Paneth cells correlate with EnO defect

Changes in corneal thickness, upper and lower tear film in seasonal allergic conjunctivitis by steroid treatment: anterior segment optical coherence tomography study

PURPOSE

To evaluate the effects of loteprednol etabonate on cornea and tear film in patients with seasonal allergic conjunctivitis by anterior segment optical coherence tomography (OCT).

METHODS

The right eyes of 52 subjects with seasonal allergic conjunctivitis were evaluated in the study. Central corneal thickness (CCT), the thicknesses of central corneal epithelium (CET) and central non-epithelial cornea (CnET), and lower and upper tear meniscus areas were measured by spectral-domain OCT and ocular surface disease index (OSDI) were obtained at baseline. After topical use of loteprednol etabonate 0.5% eye drop three times a day for 1 week, the measurements were repeated. Paired T test was used for analysis.

RESULTS

Mean CCT and mean thicknesses of CET and CnET at baseline were 528.19 ± 34.47 µm, 64.10 ± 5.30 µm and 462.84 ± 33.43 µm, respectively, and these were 526.31 ± 33.37 µm, 64.65 ± 4.84 µm and 459.84 ± 32.11 µm after the treatment, respectively. OSDI score was 21.55 ± 4.40 at baseline and 13.13 ± 2.39 after 1 week. The lower and upper tear meniscus areas at baseline were 0.026 ± 0.017 mm² and 0.017 ± 0.007 mm², respectively, and they were 0.017 ± 0.009 mm² and 0.016 ± 0.007 mm², respectively, after the treatment. There is statistically significant difference between before and after values of CCT, CnET, lower tear meniscus area and OSDI score (p < 0.05).

CONCLUSION

There is no change in corneal epithelial thickness and upper tear meniscus area after 1-week treatment with loteprednol etabonate in patients with seasonal allergic conjunctivitis, but it may cause decrease in non-epithelial corneal thickness and lower tear meniscus area.

Corticosterone in the ventral hippocampus differentially alters accumbal dopamine output in drug-naïve and amphetamine-withdrawn rats

Dysregulation in glucocorticoid stress and accumbal dopamine reward systems can alter reward salience to increase motivational drive in control conditions while contributing to relapse during drug withdrawal. Amphetamine withdrawal is associated with dysphoria and stress hypersensitivity that may be mediated, in part, by enhanced stress-induced corticosterone observed in the ventral hippocampus. Electrical stimulation of the ventral hippocampus enhances accumbal shell dopamine release, establishing a functional connection between these two regions. However, the effects of ventral hippocampal corticosterone on this system are unknown. To address this, a stress-relevant concentration of corticosterone (0.24ng/0.5 μL) or vehicle were infused into the ventral hippocampus of urethane-anesthetized adult male rats in control and amphetamine withdrawn conditions. Accumbal dopamine output was assessed with in vivo chronoamperometry. Corticosterone infused into the ventral hippocampus rapidly enhanced accumbal dopamine output in control conditions, but produced a biphasic reduction of accumbal dopamine output in amphetamine withdrawal. Selectively blocking glucocorticoid-, mineralocorticoid-, or cytosolic receptors prevented the effects of corticosterone. Overall, these results suggest that the ability of corticosterone to alter accumbal dopamine output requires cooperative activation of mineralocorticoid and glucocorticoid receptors in the cytosol, which is dysregulated during amphetamine withdrawal. These findings implicate ventral hippocampal corticosterone in playing an important role in driving neural systems involved in positive stress coping mechanisms in healthy conditions, whereas dysregulation of this system may contribute to relapse during withdrawal.

Pro-inflammatory Cytokines: Cellular and Molecular Drug Targets for Glucocorticoid-induced-osteoporosis via Osteocyte

Glucocorticoids are widely used to treat varieties of allergic and autoimmune diseases, however, long-term application results in glucocorticoid-induced osteoporosis (GIOP). Inflammatory cytokines: tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) play important regulatory roles in bone metabolism, but their roles in GIOP remain largely unknown. Osteocytes can modulate the formation and function of both osteoblasts and osteoclasts, directly via gap junctions, or indirectly by transferring molecule signaling. Apoptotic osteocytes release RANKL, HMGB1 and pro-inflammatory cytokines to stimulate osteoclastogenesis. Moreover, osteocytes can secrete FGF23 to regulate bone metabolism. Exposure to high levels of GCs can drive osteocyte apoptosis and influence gap junctions, leading to bone loss. GCs treatment is regarded to produce more FGF23 to inhibit bone mineralization. GCs also disrupt the vascular to decrease osteocyte feasibility and mineral appositional rate, resulting in a decline in bone strength. Apoptotic bodies from osteocytes induced by GCs treatment can enhance production of TNF-α and IL-6. On the other hand, TNF-α and IL-6 show synergistic effects by altering osteocytes signaling towards osteoclasts and osteoblasts. In addition, TNF-α can induce osteocyte apoptosis and attribute to a worsened bone quality in GCs. IL-6 and osteocytes may interact with each other. Therefore, we hypothesize that GCs regulate osteocyteogenesis through TNF-α and IL-6, which are highly expressed around osteocyte undergoing apoptosis. In the present review, we summarized the roles of osteocytes in regulating osteoblasts and osteoclasts. Furthermore, the mechanism of GCs altered relationship between osteocytes and osteoblasts/osteoclasts. In addition, we discussed the roles of TNF-α and IL-6 in GIOP by modulating osteocytes. Lastly, we discussed the possibility of using pro-inflammatory signaling pathway as therapeutic targets to develop drugs for GIOP.

[The Use of Glucocorticoid in the Management of Adverse Effects Related to Immunocheckpoint Inhibitors]

Immunocheckpoint inhibitors (ICIs) activated the patients' tumor immunity to kill the tumor cell, and brought new hope to patients with tumor. However, a series of immunocheckpoint inhibitors related adverse effects (irAEs) may also occur based on immune injury. Glucocorticoids are the basis for the treatment of such irAEs. However, the usage, dosage and course of treatment of glucocorticoid in irAEs are different from those in classic autoimmune diseases. Meanwhile, long-term use of large doses of glucocorticoids may cause serious adverse effects too. In this paper, the mechanism, dosage forms, adverse effects and management of glucocorticoids are described in detail, providing references and suggestions for oncologists to apply glucocorticoids in clinical practice.

New insights into the novel anti-inflammatory mode of action of glucocorticoids

Inflammation is a physiological intrinsic host response to injury meant for removal of noxious stimuli and maintenance of homeostasis. It is a defensive body mechanism that involves immune cells, blood vessels and molecular mediators of inflammation. Glucocorticoids (GCs) are steroidal hormones responsible for regulation of homeostatic and metabolic functions of body. Synthetic GCs are the most useful anti-inflammatory drugs used for the treatment of chronic inflammatory diseases such as asthma, chronic obstructive pulmonary disease (COPD), allergies, multiple sclerosis, tendinitis, lupus, atopic dermatitis, ulcerative colitis, rheumatoid arthritis and osteoarthritis whereas, the long term use of GCs are associated with many side effects. The anti-inflammatory and immunosuppressive (desired) effects of GCs are usually mediated by transrepression mechanism whereas; the metabolic and toxic (undesired) effects are usually manifested by transactivation mechanism. Though GCs are most potent anti-inflammatory and immunosuppressive drugs, the common problem associated with their use is GC resistance. Several research studies are rising to comprehend these mechanisms, which would be helpful in improving the GC resistance in asthma and COPD patients. This review aims to focus on identification of new drug targets in inflammation which will be helpful in the resolution of inflammation. The ample understanding of GC mechanisms of action helps in the development of novel anti-inflammatory drugs for the treatment of inflammatory and autoimmune disease with reduced side effects and minimal toxicity.

Different effects of cortisol on pro-inflammatory gene expressions in LPS-, heat-killed E.coli-, or live E.coli-stimulated bovine endometrial epithelial cells

Background

Bacterial infections are common in postpartum dairy cows. Cortisol level has been observed to increase in dairy cows during peripartum period, and is associated with the endometrial innate immunity against pathogens like E.coli. However, the mechanism underlying how cortisol regulates E.coli-induced inflammatory response in bovine endometrial epithelial cells (BEEC) remains elusive.

Results

Cortisol decreased the expressions of IL1β, IL6, TNF-α, IL8, and TLR4 mRNA in BEEC treated with LPS or heat-killed E.coli, but up-regulated these gene expressions in BEEC stimulated by live E.coli.

Conclusion

Cortisol exerted the anti-inflammatory action on LPS- or heat-killed E.coli-stimulated BEEC, but the pro-inflammatory action on live E.coli-induced BEEC.

Taurochenodeoxycholic Acid Inhibited AP-1 Activation via Stimulating Glucocorticoid Receptor

Taurochenodeoxycholic acid (TCDCA) as a primary bioactive substance of animal bile has been shown to exert good anti-inflammatory and immunomodulatory functions in adjuvant arthritis in rats. The anti-inflammatory and immunomodulatory properties of TCDCA have exhibited interesting similarities with the effects of glucocorticoids (GCs). To investigate the potential mechanisms of TCDCA in anti-inflammation and immunomodulation, we used a luciferase reporter assay to evaluate the activation of the glucocorticoid receptor (GR) stimulated by TCDCA. Our results showed that GR was activated by TCDCA in a concentration-dependent manner. Moreover, the elevated expressions of c-Fos and phosphorylated c-Jun induced by interleukin-1β (IL-1β) were reversed by TCDCA. The inhibition of TCDCA on the transactivation of activator protein-1 (AP-1) was observed as well. However, the suppression of TCDCA on the phosphorylation of c-Jun was blocked incompletely by GR inhibitor RU486. These results have indicated that the anti-inflammatory and immunomodulatory functions of TCDCA involve multiple pathways, with contributions from GR and its related AP-1 signaling pathway.

ICON: Diagnosis and management of allergic conjunctivitis

Ocular allergy (OA), interchangeably known as allergic conjunctivitis, is a common immunological hypersensitivity disorder affecting up to 40% of the population. Ocular allergy has been increasing in frequency, with symptoms of itching, redness, and swelling that significantly impacts an individual's quality of life (QOL). Ocular allergy is an often underdiagnosed and undertreated health problem, because only 10% of patients with OA symptoms seek medical attention, whereas most patients manage with over-the-counter medications and complementary nonpharmacological remedies. The clinical course, duration, severity, and co-morbidities are varied and depend, in part, on the specific ocular tissues that are affected and on immunologic mechanism(s) involved, both local and systemic. It is frequently associated with allergic rhinitis (commonly recognized as allergic rhino conjunctivitis), and with other allergic comorbidities. The predominance of self-management increases the risk of suboptimal therapy that leads to recurrent exacerbations and the potential for development of more chronic conditions that can lead to corneal complications and interference with the visual axis. Multiple, often co-existing causes are seen, and a broad differential diagnosis for OA, increasing the difficulty of arriving at the correct diagnosis(es). Ocular allergy commonly overlaps with other anterior ocular disease disorders, including infectious disorders and dry eye syndromes. Therefore, successful management includes overcoming the challenges of underdiagnosis and even misdiagnosis by a better understanding of the subtleties of an in-depth patient history, ophthalmologic examination techniques, and diagnostic procedures, which are of paramount importance in making an accurate diagnosis of OA. Appropriate cross-referral between specialists (allergists and eyecare specialists) would maximize patient care and outcomes. This would significantly improve OA management and overcome the unmet needs in global health.

Comparison of In Vitro and In Vivo Percutaneous Absorption Across Human Skin Using BAY1003803 Formulated as Ointment and Cream

Direct comparisons between skin absorption data and clinical pharmacokinetic data are rare. Here we use the lipophilic nonsteroidal selective glucocorticoid receptor agonist BAY1003803 to make such a comparison. The objective is to find the extent to which measurements of skin permeation in vitro can be used to predict the corresponding permeation in vivo for human pharmacokinetics of topically applied substances. BAY1003803 was prepared in various formulations: ointment, hydrophilic cream, lipophilic cream, and milk. Its ability to permeate healthy human skin was measured in vitro in static diffusion cells, and percutaneous absorption as well as dermal delivery was measured thereafter, for 2 selected formulations, in vivo in healthy volunteers. Absorption in vivo comparing ointment and lipophilic cream was correlated with expectation based on the dermal delivery obtained in vitro. A 2.17-fold higher systemic exposure to BAY1003803 was achieved by the ointment formulation. This is well in line with the predicted exposure difference of 2.74 based on the in vitro data. In conclusion, in vitro skin absorption studies using human skin are suitable for the prediction of systemic exposure and formulation effects in vivo; they can therefore be applied to guide the design of clinical investigations of dermatological preparations.

IRF2BP2 modulates the crosstalk between glucocorticoid and TNF signaling

IRF2BP2 (interferon regulatory factor-2 binding protein-2) is an uncharacterized interaction partner of glucocorticoid (GC) receptor (GR), an anti-inflammatory and metabolic transcription factor. Here, we show that GC changes the chromatin binding of IRF2BP2 in natural chromatin milieu. The GC-induced IRF2BP2-binding sites co-occur with GR binding sites and are associated with GC-induced genes. Moreover, the depletion of IRF2BP2 modulates transcription of GC-regulated genes, represses cell proliferation and increases cell movement in HEK293 cells. In A549 cells, the depletion extensively alters the responses to GC and tumor necrosis factor α (TNF), including metabolic and inflammatory pathways. Taken together, our data support the role of IRF2BP2 as a coregulator of both GR and NF-κB, potentially modulating the crosstalk between GC and TNF signaling.

Immunopathologic Effects of Prednisolone and Cyclosporine A on Feline Immunodeficiency Virus Replication and Persistence

Feline immunodeficiency virus (FIV) induces opportunistic disease in chronically infected cats, and both prednisolone and cyclosporine A (CsA) are clinically used to treat complications such as lymphoma and stomatitis. However, the impact of these compounds on FIV infection are still unknown and understanding immunomodulatory effects on FIV replication and persistence is critical to guide safe and effective therapies. To determine the immunologic and virologic effects of prednisolone and CsA during FIV infection, FIV-positive cats were administered immunosuppressive doses of prednisolone (2 mg/kg) or CsA (5 mg/kg). Both prednisolone and CsA induced acute and transient increases in FIV DNA and RNA loads as detected by quantitative PCR. Changes in the proportion of lymphocyte immunophenotypes were also observed between FIV-infected and naïve cats treated with CsA and prednisolone, and both treatments caused acute increases in CD4+ lymphocytes that correlated with increased FIV RNA. CsA and prednisolone also produced alterations in cytokine expression that favored a shift toward a Th2 response. Pre-treatment with CsA slightly enhanced the efficacy of antiretroviral therapy but did not enhance clearance of FIV. Results highlight the potential for drug-induced perturbation of FIV infection and underscore the need for more information regarding immunopathologic consequences of therapeutic agents on concurrent viral infections.

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.

Glucocorticoids-All-Rounders Tackling the Versatile Players of the Immune System

Glucocorticoids regulate fundamental processes of the human body and control cellular functions such as cell metabolism, growth, differentiation, and apoptosis. Moreover, endogenous glucocorticoids link the endocrine and immune system and ensure the correct function of inflammatory events during tissue repair, regeneration, and pathogen elimination via genomic and rapid non-genomic pathways. Due to their strong immunosuppressive, anti-inflammatory and anti-allergic effects on immune cells, tissues and organs, glucocorticoids significantly improve the quality of life of many patients suffering from diseases caused by a dysregulated immune system. Despite the multitude and seriousness of glucocorticoid-related adverse events including diabetes mellitus, osteoporosis and infections, these agents remain indispensable, representing the most powerful, and cost-effective drugs in the treatment of a wide range of rheumatic diseases. These include rheumatoid arthritis, vasculitis, and connective tissue diseases, as well as many other pathological conditions of the immune system. Depending on the therapeutically affected cell type, glucocorticoid actions strongly vary among different diseases. While immune responses always represent complex reactions involving different cells and cellular processes, specific immune cell populations with key responsibilities driving the pathological mechanisms can be identified for certain autoimmune diseases. In this review, we will focus on the mechanisms of action of glucocorticoids on various leukocyte populations, exemplarily portraying different autoimmune diseases as heterogeneous targets of glucocorticoid actions: (i) Abnormalities in the innate immune response play a crucial role in the initiation and perpetuation of giant cell arteritis (GCA). (ii) Specific types of CD4+ T helper (Th) lymphocytes, namely Th1 and Th17 cells, represent important players in the establishment and course of rheumatoid arthritis (RA), whereas (iii) B cells have emerged as central players in systemic lupus erythematosus (SLE). (iv) Allergic reactions are mainly triggered by several different cytokines released by activated Th2 lymphocytes. Using these examples, we aim to illustrate the versatile modulating effects of glucocorticoids on the immune system. In contrast, in the treatment of lymphoproliferative disorders the pro-apoptotic action of glucocorticoids prevails, but their mechanisms differ depending on the type of cancer. Therefore, we will also give a brief insight into the current knowledge of the mode of glucocorticoid action in oncological treatment focusing on leukemia.

GR Dimerization and the Impact of GR Dimerization on GR Protein Stability and Half-Life

Pharmacologically, glucocorticoids, which mediate their effects via the glucocorticoid receptor (GR), are a most effective therapy for inflammatory diseases despite the fact that chronic use causes side-effects and acquired GC resistance. The design of drugs with fewer side-effects and less potential for the development of resistance is therefore considered crucial for improved therapy. Dimerization of the GR is an integral step in glucocorticoid signaling and has been identified as a possible molecular site to target for drug development of anti-inflammatory drugs with an improved therapeutic index. Most of the current understanding regarding the role of GR dimerization in GC signaling derives for dimerization deficient mutants, although the role of ligands biased toward monomerization has also been described. Even though designing for loss of dimerization has mostly been applied for reduction of side-effect profile, designing for loss of dimerization may also be a fruitful strategy for the development of GC drugs with less potential to develop GC resistance. GC-induced resistance affects up to 30% of users and is due to a reduction in the GR functional pool. Several molecular mechanisms of GC-mediated reductions in GR pool have been described, one of which is the autologous down-regulation of GR density by the ubiquitin-proteasome-system (UPS). Loss of GR dimerization prevents autologous down-regulation of the receptor through modulation of interactions with components of the UPS and post-translational modifications (PTMs), such as phosphorylation, which prime the GR for degradation. Rational design of conformationally biased ligands that select for a monomeric GR conformation, which increases GC sensitivity through improving GR protein stability and increasing half-life, may be a productive avenue to explore. However, potential drawbacks to this approach should be considered as well as the advantages and disadvantages in chronic vs. acute treatment regimes.

Intra-articular triamcinolone acetonide improves lung function in horses with severe asthma

BACKGROUND

Locally administered corticosteroids are commonly used to treat joint diseases in sport and racehorses. As they are also the most potent drugs for the treatment of equine asthma, we hypothesised that the intra-articular corticosteroids used to treat joint diseases also improve the lung function in horses with severe asthma, thus potentially delaying the diagnosis of this common lung condition.

OBJECTIVES

To compare the effects of intra-articular (IA) and intramuscular (IM) triamcinolone acetonide (TA) on lung function in horses with severe asthma.

STUDY DESIGN

Randomised and controlled experiment on asthma-prone research animals.

METHODS

Horses with severe asthma in clinical exacerbation were given either 20 mg of TA in both tarsocrural joints (n = 5; 40 mg/horse) or 40 mg of TA intramuscularly (n = 5). Lung function and TA serum concentrations were measured weekly for 35 days. TA serum concentrations were also evaluated on day 3.

RESULTS

The pulmonary resistance (R_L ) and elastance (E_L ) values decreased by day 7 in the IA group (P<0.0001 and P = 0.003, respectively) and by day 14 in the IM group (P = 0.002 and 0.03, respectively). Lung function was improved up to days 21 and 28 in the IA and IM groups, respectively, when compared with baseline. TA serum levels were below the quantification limit (100 pg/ml) for 4 and 3 of the 5 horses in the IA and IM groups, respectively, on day 7. The area under the curve for R_L , E_L and the serum concentrations of TA were similar in both groups.

MAIN LIMITATIONS

The response of horses with severe asthma might differ from that of high-performance horses with mild/moderate asthma.

CONCLUSIONS

Intra-articular administration of TA improves lung function in horses with severe asthma, an effect that persists when TA serum concentration is below the quantification level that is employed as a threshold by the International Association of Racing Commissioners.

Pharmacology and pharmacogenetics of prednisone and prednisolone in patients with nephrotic syndrome

Nephrotic syndrome is one of the most common glomerular disorders in childhood. Glucocorticoids have been the cornerstone of the treatment of childhood nephrotic syndrome for several decades, as the majority of children achieves complete remission after prednisone or prednisolone treatment. Currently, treatment guidelines for the first manifestation and relapse of nephrotic syndrome are mostly standardized, while large inter-individual variation is present in the clinical course of disease and side effects of glucocorticoid treatment. This review describes the mechanisms of glucocorticoid action and clinical pharmacokinetics and pharmacodynamics of prednisone and prednisolone in nephrotic syndrome patients. However, these mechanisms do not account for the large inter-individual variability in the response to glucocorticoid treatment. Previous research has shown that genetic factors can have a major influence on the pharmacokinetic and dynamic profile of the individual patient. Therefore, pharmacogenetics may have a promising role in personalized medicine for patients with nephrotic syndrome. Currently, little is known about the impact of genetic polymorphisms on glucocorticoid response and steroid-related toxicities in children with nephrotic syndrome. Although the evidence is limited, the data summarized in this study do suggest a role for pharmacogenetics to improve individualization of glucocorticoid therapy. Therefore, studies in larger cohorts with nephrotic syndrome patients are necessary to draw final conclusions about the influence of genetic polymorphisms on the glucocorticoid response and steroid-related toxicities to ultimately implement pharmacogenetics in clinical practice.

L-Thyroxine induces thermotolerance in yeast

The cellular stress response (CSR) is a universal inducible reaction modulated, among others, by heat, drugs, and hormones. We aimed to investigate the role of L-thyroxine (T4) on the heat shock (HS) response in Saccharomyces cerevisiae. The CSR was evaluated by determining growth and viability of post-logarithmic phase grown yeast cultures after HS at 53 °C for 30 min. We found that long-term T4 exposure can induce a dose-dependent and Hsp90 and H+ trafficking-related thermotolerance in yeast.

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.

Deciphering the Potential Pharmaceutical Mechanism of GUI-ZHI-FU-LING-WAN on Systemic Sclerosis based on Systems Biology Approaches

Systemic sclerosis (SSc; scleroderma) is a complicated idiopathic connective tissue disease with seldom effective treatment. GUI-ZHI-FU-LING-WAN (GFW) is a classic Traditional Chinese Medicine (TCM) formula widely used for the treatment of SSc. However, the mechanism of how the GFW affects SSc remains unclear. In this study, the system biology approach was utilized to analyze herb compounds and related targets to get the general information of GFW. The KEGG enrichment analysis of 1645 related targets suggested that the formula is involved in the VEGF signaling pathway, the Toll-like receptor signaling pathway, etc. Quantitative and qualitative analysis of the relationship among the 3 subsets (formula targets, drug targets and disease genes) showed that the formula targets overlapped with 38.0% drug targets and 26.0% proteins encoded by disease genes. Through the analysis of SSc related microarray statistics from the GEO database, we also validated the consistent expression behavior among the 3 subsets before and after treatment. To further reveal the mechanism of prescription, we constructed a network among 3 subsets and decomposed it into 24 modules to decipher how GFW interfere in the progress of SSc. The modules indicated that the intervention may come into effect through following pathogenic processes: vasculopathy, immune dysregulation and tissue fibrosis. Vitro experiments confirmed that GFW could suppress the proliferation of fibroblasts and decrease the Th1 cytokine (TNF-α, MIP-2 and IL-6) expression for lipopolysaccharide (LPS) and bleomycin (BLM) stimulation in macrophages, which is consistent with previous conclusion that GFW is able to relieve SSc. The systems biology approach provides a new insight for deepening understanding about TCM.

Glucocorticoid signaling and osteoarthritis

Glucocorticoids are steroid hormones synthesized and released by the adrenal cortex. Their main function is to maintain cell homeostasis through a variety of signaling pathways, responding to changes in an organism's environment or developmental status. Mimicking the actions of natural glucocorticoids, synthetic glucocorticoids have been recruited to treat many diseases that implicate glucocorticoid receptor signaling such as osteoarthritis. In osteoarthritis, synthetic glucocorticoids aim to alleviate inflammation and pain. The variation of patients' response and the possibility of complications associated with their long-term use have led to a need for a better understanding of glucocorticoid receptor signaling in osteoarthritis. In this review, we performed a literature search in the molecular pathways that link the osteoarthritic joint to the glucocorticoid receptor signaling. We hope that this information will advance research in the field and propose new molecular targets for the development of more optimized therapies for osteoarthritis.

Investigation of Combined Cyclodextrin and Hydrogel Formulation for Ocular Delivery of Dexamethasone Acetate by Means of Experimental Designs

Dexamethasone acetate (DXMa) has proven its efficiency to treat corneal inflammation, without a great propensity to increase intraocular pressure. Unfortunately, its poor aqueous solubility, associated with a rapid precorneal elimination, results in a low drug bioavailability and a low penetration after topical ocular administration. The main objective of this study was to improve the apparent aqueous solubility of DXMa using cyclodextrins. First, hydroxypropyl-β-CD (HPβCD) and hydroxypropyl-γ-CD (HPγCD) were used to enhance DXMa concentration in aqueous solution. The β and γ HPCD derivatives allowed the increase of the DXMa amount in solution at 25 °C by a factor of 500 and 1500, respectively. Second, with the aim of improving the persistence of the complex solution after instillation in the eye, the formulations of DXMa-based CD solutions with marketed ophthalmic gels (CELLUVISC^®, GEL-LARMES^®, and VISMED^®) were investigated and optimized by means of special cubic mixture designs, allowing the defining of mixed gels loaded with 0.7% (HPβCD) and 2% (HPγCD) DXMa with osmolality within acceptable physiological range. Finally, in vitro drug release assays from the mixed gels were performed and compared with reference eye drops. Similarly to MAXIDEX^® and DEXAFREE^®, in the case of mixed gel containing HPβCD, more than 90% of the drug was released within 2 h, while in mixed gel containing HPγCD, the release of DXMa was partial, reaching ≈60% in 2 h. This difference will have to be further addressed with ex vivo and in vivo ocular delivery experiments.

New Functions of Classical Compounds against Orofacial Inflammatory Lesions

Anti-inflammatory agents have been widely used to ameliorate severe inflammatory symptoms of a number of diseases, and such therapeutics are particularly useful for diseases with intolerable pain without significant mortality. A typical example of this is a disease known as stomatitis; although stomatitis itself is not a life-threatening disease, it severely impairs the individual’s quality of life, and thus a standard therapeutic strategy for it has already been established. The topical application of a bioactive agent is quite easy, and a strong anti-inflammatory agent can be used without significant adverse effects. In contrast, natural products with relatively mild bioactivity are used for systemic intervention. However, new aspects of classical drugs used in these established therapeutic methods have recently been discovered, which is expanding the utility of these compounds to other oral diseases such as osteoarthritis of temporomandibular joints (TMJ-OA). In this review article, after summarizing the general concept and pathobiology of stomatitis, its established therapeutics are explained. Thereafter, recent advances in the research into related compounds, which is uncovering new biological functions of the agents used therein, are introduced. Indeed, regenerative therapeutics for TMJ-OA may be developed with the classical compounds currently being used.

Porcine-induced pluripotent stem cell-derived osteoblast-like cells ameliorate trabecular bone mass of osteoporotic rats

AIM

We created rat models of osteoporosis and verified a novel idea to recover bone mass via local cell transplantation.

MATERIALS & METHODS

The rats were treated with ovariectomy, 0.1% calcium diet or 3 mg/kg body weight/day of prednisolone and porcine-induced pluripotent stem cell (piPSC)-derived osteoblast-like cells were transplanted into the medullary cavity of the left femurs.

RESULTS

The piPSC-derived osteoblast-like cells exerted therapeutic potential on prednisolone treatment group, which confirmed by improvements in trabecular bone volume (15.93 ± 2.20%), bone surface/volume ratio (27.82 ± 1.40 1/mm), thickness (1.40 ± 0.01 mm), separation (0.99 ± 0.10 mm), number (1.13 ± 0.13 1/mm) and total porosity (84.06 ± 2.20%).

CONCLUSION

These results first uncovered therapeutic potential of xenotransplantation with piPSCs for glucocorticoid-induced osteoporosis treatment in the rat models.

Glucocorticoids in multiple myeloma: past, present, and future

Glucocorticoids are a backbone of treatment for multiple myeloma in both the upfront and relapsed/refractory setting. While glucocorticoids have single agent activity in multiple myeloma, in the modern era, they are paired with novel agents to induce high clinical response rates. On the other hand, toxicities of steroid therapy limit high dose delivery and impact patient quality of life. We provide a history of steroid use in multiple myeloma with the aim to understand how steroids have emerged and persisted in the treatment of multiple myeloma. We review mechanisms of glucocorticoid sensitivity and resistance and highlight potential future directions to evaluate steroid responsiveness. Further research in this area will aid in optimizing steroid utilization and help determine when glucocorticoid therapy may no longer benefit patients.

Pharmacokinetics and Bioavailability Study of a Prednisolone Tablet as a Single Oral Dose in Bangladeshi Healthy Volunteers

The aim of the study was to assess the pharmacokinetic and bioavailability of 2 formulations of 5-mg prednisolone tablets, reference product (Teva UK Limited) and Pred (Eskayef Bangladesh Ltd) as test product. The open-label, randomized, 2-way crossover studies were conducted on 14 healthy subjects. Participants were assigned to receive both products as a single dose (20 mg formulations, 4 × 5 mg tablets) followed by a 2 weeks’ washout period. Following oral administration, samples were obtained at various time intervals and analyzed for prednisolone concentrations using a validated high-performance liquid chromatography assay method with ultraviolet detection. The obtained values for test and reference products were 683.00 ± 94.54 ng/mL and 635.16 ± 125.57 ng/mL for C_max; 2716.54 ± 196.28 ng·h/mL and 2780.5 ± 119.73 ng·h/mL for AUC_0-12; 3284.36 ± 138.12 ng·h/mL and 3317.96 ± 133.95 ng·h/mL for AUC_0-∞, respectively. From the paired Student t test, no significant differences between 2 formulations were observed (P > .05). The 90% confidence intervals of C_max, AUC_0-12, and AUC_0-∞ were found to be 99.0% to 100.9%, 99.4% to 100.5%, and 99.9% to 101.3%, respectively. Finally, it can be concluded that Pred (Test) of Eskayef Bangladesh Ltd and prednisolone (Reference) of Teva UK Limited are bioequivalent and interchangeable.

The Electrical Stimulation of the Bed Nucleus of the Stria Terminalis Causes Oxidative Stress in Skeletal Muscle of Rats

Recent studies indicate that activation of hypothalamus-pituitary-adrenocortical axis (HPA) plays the crucial role in stress response, while several lines of evidence mark the bed nucleus of the stria terminalis (BST) as a major mediator of the HPA axis responses to stress. The purpose of this study was to investigate the influence of the corticosterone flux induced by the electrical stimulation of BST on markers of free radical damage of lipids and proteins and antioxidant enzyme activity in skeletal muscle of rats. The male Wistar rats were used and assigned to one of three groups: sham-operated (SHM; n = 6), two-week (ST2; n = 6), and four-week stimulated (ST4; n = 5) groups. Blood, soleus, and extensor digitorum longus muscles were collected. The chronic, 4-week electrical stimulation of the BST evokes increased plasma corticosterone concentration, which resulted in oxidative stress in skeletal muscles. We found higher level of lipid peroxidation markers, lower level of protein oxidation marker, and elevated antioxidant enzyme activity in both muscles. Our findings have also potential implication showing that reaction to the long-term “psychological stress” may lead to free radical damage of muscle.

Glucocorticoids as an adjunct to oncologic treatment in solid malignancies - Not an innocent bystander

Glucocorticoids are steroidal hormones which exert their action via genomic and non-genomic mechanisms. In the clinical setting, glucocorticoids are utilized for their anti-inflammatory, anti-allergenic and immunomodulatory effects and for their well-established, pro-apoptotic effects on hematological malignancies. In the treatment of solid tumors, glucocorticoids serve primarily for alleviation of tumor- and treatment-related symptoms and in most cases are not considered to have a direct effect on tumor growth and spread. However, significant pre-clinical data suggest that glucocorticoids have diverse effects on tumor progression, both pro- and anti- tumorigenic. In contrast, the clinical data regarding the pro- and anti-tumorigenic effects of glucocorticoids on solid tumors is scarce, and summarized in this review. The following review presents the suggested glucocorticoids mechanism of action and the effects of glucocorticoids on tumor cells, on the tumor microenvironment and on tumor response to cytotoxic therapy, in the pre-clinical and clinical settings.

Preclinical pharmacology of AZD9977: A novel mineralocorticoid receptor modulator separating organ protection from effects on electrolyte excretion

Excess mineralocorticoid receptor (MR) activation promotes target organ dysfunction, vascular injury and fibrosis. MR antagonists like eplerenone are used for treating heart failure, but their use is limited due to the compound class-inherent hyperkalemia risk. Here we present evidence that AZD9977, a first-in-class MR modulator shows cardio-renal protection despite a mechanism-based reduced liability to cause hyperkalemia. AZD9977 in vitro potency and binding mode to MR were characterized using reporter gene, binding, cofactor recruitment assays and X-ray crystallopgraphy. Organ protection was studied in uni-nephrectomised db/db mice and uni-nephrectomised rats administered aldosterone and high salt. Acute effects of single compound doses on urinary electrolyte excretion were tested in rats on a low salt diet. AZD9977 and eplerenone showed similar human MR in vitro potencies. Unlike eplerenone, AZD9977 is a partial MR antagonist due to its unique interaction pattern with MR, which results in a distinct recruitment of co-factor peptides when compared to eplerenone. AZD9977 dose dependently reduced albuminuria and improved kidney histopathology similar to eplerenone in db/db uni-nephrectomised mice and uni-nephrectomised rats. In acute testing, AZD9977 did not affect urinary Na+/K+ ratio, while eplerenone increased the Na+/K+ ratio dose dependently. AZD9977 is a selective MR modulator, retaining organ protection without acute effect on urinary electrolyte excretion. This predicts a reduced hyperkalemia risk and AZD9977 therefore has the potential to deliver a safe, efficacious treatment to patients prone to hyperkalemia.

An Approach to Greater Specificity for Glucocorticoids

Glucocorticoid steroids are among the most prescribed drugs each year. Nonetheless, the many undesirable side effects, and lack of selectivity, restrict their greater usage. Research to increase glucocorticoid specificity has spanned many years. These efforts have been hampered by the ability of glucocorticoids to both induce and repress gene transcription and also by the lack of success in defining any predictable properties that control glucocorticoid specificity. Correlations of transcriptional specificity have been observed with changes in steroid structure, receptor and chromatin conformation, DNA sequence for receptor binding, and associated cofactors. However, none of these studies have progressed to the point of being able to offer guidance for increased specificity. We summarize here a mathematical theory that allows a novel and quantifiable approach to increase selectivity. The theory applies to all three major actions of glucocorticoid receptors: induction by agonists, induction by antagonists, and repression by agonists. Simple graphical analysis of competition assays involving any two factors (steroid, chemical, peptide, protein, DNA, etc.) yields information (1) about the kinetically described mechanism of action for each factor at that step where the factor acts in the overall reaction sequence and (2) about the relative position of that step where each factor acts. These two pieces of information uniquely provide direction for increasing the specificity of glucocorticoid action. Consideration of all three modes of action indicate that the most promising approach for increased specificity is to vary the concentrations of those cofactors/pharmaceuticals that act closest to the observed end point. The potential for selectivity is even greater when varying cofactors/pharmaceuticals in conjunction with a select class of antagonists.

Dexamethasone inhibits inflammatory response via down regulation of AP-1 transcription factor in human lung epithelial cells

The production of inflammatory mediators by epithelial cells in inflammatory lung diseases may represent an important target for the anti-inflammatory effects of glucocorticoids. Activator protein-1 is a major activator of inflammatory genes and has been proposed as a target for inhibition by glucocorticoids. We have used human pulmonary type-II A549 cells to examine the effect of dexamethasone on the phorbol ester (PMA)/Lipopolysaccharide (LPS) induced pro-inflammatory cytokines and AP-1 factors. A549 cells were treated with and without PMA or LPS or dexamethasone and the cell viability and nitric oxide production was measured by MTT assay and Griess reagent respectively. Expression of pro-inflammatory cytokines and AP-1 factors mRNA were measured using semi quantitative RT-PCR. The PMA/LPS treated cells show significant 2-3 fold increase in the mRNA levels of pro-inflammatory cytokines (IL-1β, IL-2, IL-6, IL-8 and TNF-α), cyclo‑oxygenase-2 (COX-2) and specific AP-1 factors (c-Jun, c-Fos and Jun-D). Whereas, pretreatment of cells with dexamethasone significantly inhibited the LPS induced nitric oxide production and PMA/LPS induced mRNAs expression of above pro-inflammatory cytokines, COX-2 and AP-1 factors. Cells treated with dexamethasone alone at both the concentrations inhibit the mRNAs expression of IL-1β, IL-6 and TNF-α compared to control. Our study reveals that dexamethasone decreased the mRNAs expression of c-Jun and c-Fos available for AP-1 formation suggested that AP-1 is the probable key transcription factor involved in the anti-inflammatory activity of dexamethasone. This may be an important molecular mechanism of steroid action in asthma and other chronic inflammatory lung diseases which may be useful for treatment of lung inflammatory diseases.

Corticosteroids in the management of acute multiple sclerosis exacerbations

Multiple sclerosis (MS) is an autoimmune, inflammatory demyelinating disease of the central nervous system characterized in the majority of the patients by a relapsing-remitting disease course. For decades high-dosage corticosteroids (CS) are considered the cornerstone in the management of acute MS relapses. However, many unanswered questions remain when it comes to the exact modalities of CS administration. In this review on behalf of the Belgian Study Group for MS we define the efficacy of CS in reducing MS-related morbidity and examine whether the effect is different according to type of CS, route of administration, cumulative dosage, timing of initiation and disease course. We also review the use of CS in combination with other MS treatments and during pregnancy and lactation. Furthermore, we delineate the relevant adverse events due to a pulse CS regimen and present a decision tree that can be used when treating MS relapses in clinical practice.

Development of nonsteroidal glucocorticoid receptor modulators based on N-benzyl-N-(4-phenoxyphenyl)benzenesulfonamide scaffold

N-Benzyl-N-(4-phenoxyphenyl)benzenesulfonamide derivatives were developed as a novel class of nonsteroidal glucocorticoid receptor (GR) modulators, which are promising drug candidates for treating immune-related disorders. Focusing on the similarity of the GR and progesterone receptor (PR) ligand-binding domain (LBD) structures, we adopted our recently developed PR antagonist 10 as a lead compound and synthesized a series of derivatives. We found that the N-(4-phenoxyphenyl)benzenesulfonamide skeleton serves as a versatile scaffold for GR antagonists. Among them, 4-cyano derivative 14m was the most potent, with an IC₅₀ value of 1.43μM for GR. This compound showed good selectivity for GR; it retained relatively weak antagonistic activity toward PR (IC₅₀ for PR: 8.00μM; 250-fold less potent than 10), but showed no activity toward AR, ERα or ERβ. Interestingly, the 4-amino derivative 15a exhibited transrepression activity toward NF-κB in addition to GR-antagonistic activity, whereas 14m did not. The structure-activity relationship for transrepression was different from that for GR-antagonistic activity. Computational docking simulations suggested that 15a might bind to the ligand-binding pocket of GR in a different manner from 14m. These findings open up new possibilities for developing novel nonsteroidal GR modulators with distinctive activity profiles.

Prednisolone induces apoptosis in corneal epithelial cells through the intrinsic pathway

Glucocorticoid eye drops are one of the most widely used medications in ophthalmology. However, little is known about the effects of glucocorticoids on corneal epithelial cells that are directly exposed to topically-administered glucocorticoids. Here we investigated the effects of prednisolone, a synthetic glucocorticoid analogue frequently used in the clinic, on corneal epithelial cells. Results showed that prednisolone decreased survival of corneal epithelial cells by inhibiting proliferation and inducing apoptosis in a dose-dependent manner. The levels of mitochondrial reactive oxygen species (mtROS), cleaved caspase-3, and -9 were increased by prednisolone. The effects of prednisolone on apoptosis and mtROS were blocked 1) by the glucocorticoid receptor (GR) antagonist RU-38486, 2) in cells with GR siRNA knockdown, and 3) by treatment with N-acetylcysteine. Transcript levels of pro-inflammatory cytokines were increased in corneal epithelial cells upon hyperosmolar stress, but repressed by prednisolone. In NOD.B10.H2^b mice, topical administration of 1% prednisolone increased apoptotic cells in the corneal epithelium. Together, data indicate that prednisolone induces apoptosis in corneal epithelial cells through GR and the intrinsic pathway involving mtROS, caspase-9, and -3. The pro-apoptotic effects of glucocorticoids along with their anti-inflammatory effects should be considered when glucocorticoid eye drops are used in patients with ocular surface disease.

Rheumatoid arthritis: Recent advances on its etiology, role of cytokines and pharmacotherapy

An autoimmune disease is defined as a clinical syndrome resulted from an instigation of both T cell and B cell or individually, in the absence of any present infection or any sort of distinguishable cause. Clonal deletion of auto reactive cells remains the central canon of immunology for decades, keeping the role of T cell and B cell aside, which are actually the guards to recognize the entry of foreign body. According to NIH, 23.5 million Americans are all together affected by these diseases. They are rare, but with the exception of RA. Rheumatoid arthritis is chronic and systemic autoimmune response to the multiple joints with unknown ethology, progressive disability, systemic complications, early death and high socioeconomic costs. Its ancient disease with an old history found in North American tribes since 1500 BCE, but its etiology is yet to be explored. Current conventional and biological therapies used for RA are not fulfilling the need of the patients but give only partial responses. There is a lack of consistent and liable biomarkers of prognosis therapeutic response, and toxicity. Rheumatoid arthritis is characterized by hyperplasic synovium, production of cytokines, chemokines, autoantibodies like rheumatoid factor (RF) and anticitrullinated protein antibody (ACPA), osteoclastogensis, angiogenesis and systemic consequences like cardiovascular, pulmonary, psychological, and skeletal disorders. Cytokines, a diverse group of polypeptides, play critical role in the pathogenesis of RA. Their involvement in autoimmune diseases is a rapidly growing area of biological and clinical research. Among the proinflammatory cytokines, IL-1α/β and TNF-α trigger the intracellular molecular signalling pathway responsible for the pathogenesis of RA that leads to the activation of mesenchymal cell, recruitment of innate and adaptive immune system cells, activation of synoviocytes which in term activates various mediators including tumour necrosis factor-alpha (TNF-α), interleukin-1 (IL-1), interleukin-6 (IL-6) and interleukin-8 (IL-8), resulting in inflamed synovium, increase angiogenesis and decrease lymphangiogensis. Their current pharmacotherapy should focus on their three phases of progression i.e. prearthritis phase, transition phase and clinical phase. In this way we will be able to find a way to keep the balance between the pro and anti-inflammatory cytokines that is believe to be the dogma of pathogenesis of RA. For this we need to explore new agents, whether from synthetic or natural source to find the answers for unresolved etiology of autoimmune diseases and to provide a quality of life to the patients suffering from these diseases specifically RA.

GLUCOCORTICOID-INDUCED BONE DISEASE: MECHANISMS AND IMPORTANCE IN PEDIATRIC PRACTICE

OBJECTIVE

To describe mechanisms by which glucocorticoids cause osteoporosis, with fracture risk, combining this learning with a possible professional behavior change.

DATA SOURCES

A systematic search on SciELO, PubMed, Scopus, and Medline databases was carried out for consensus, review articles, including systematic reviews and meta-analysis, which were published in English, between 2000 and 2016. Keywords used on the search were the following: glucocorticoids, fractures, osteoporosis, bone health, vitamin D, children, and adolescents.

DATA SYNTHESIS

The review was divided into four topics: 1) introduction, with a brief focus on pediatric fractures; 2) osteoporosis in children and adolescents, highlighting it as a silent cause of fractures; 3) glucocorticoids and secondary bone disease, describing deleterious mechanisms of this steroids group on bone structure; 4) molecular effects of glucocorticoids excess on bone, with details about the harmful mechanisms on bone molecular level.

CONCLUSIONS

Glucocorticoids excess determines early bone disease, favoring the occurrence of fractures. Thus, a child or an adolescent who uses glucocorticoids, especially systemically and chronically, but also repeats cycles at high cumulative doses of the medication, needs care and guidance related to bone health at the onset of treatment. On the other hand, the presence of fractures, even if related to trauma, can be a sign of underlying and unknown bone fragility, which may be secondary to the use of glucocorticoids and/or vitamin D deficiency.

Pharmacological targeting of allergen-specific T lymphocytes

Allergic disorders are the result of a complex pathophysiology, involving major cellular lineages and a multitude of humoral factors of the innate and adaptive immune system, and have the tendency to involve multiple organs. Consequently, even standard pharmacological treatment of allergies is rarely specific but usually targets more than one pathway/cellular system at a time. Accordingly, many of the classic anti-allergic drugs have a critical impact also on T helper cells, which are pivotal not only during the sensitization but also the maintenance phase of allergic diseases. Recent years have seen a dramatic increase of novel drugs with the potency to interfere, more or less specifically, with T lymphocyte function, which might, possibly together with classic anti-allergic drugs, help harnessing one of the central cellular players in allergic responses. A major theme in the years to come will be a thoughtful combination of previously established with recently developed treatment modalities.

Class I lysine deacetylases promote glucocorticoid-induced transcriptional repression through functional interaction with LSD1

Small molecule inhibitors of lysine deacetylases (KDACs) are approved for clinical use in treatment of several diseases. Nuclear receptors, such as the glucocorticoid receptor (GR) use lysine acetyltransferases (KATs or HATs) and KDACs to regulate transcription through acetylation and deacetylation of protein targets such as histones. Previously we have shown that KDAC1 activity facilitates GR-activated transcription at about half of all cellular target genes. In the current study we examine the role of Class I KDACs in glucocorticoid-mediated repression of gene expression. Inhibition of KDACs through two structurally distinct Class I-selective inhibitors prevented dexamethasone (Dex)-mediated transcriptional repression in a gene-selective fashion. In addition, KDAC activity is also necessary to maintain repression. Steroid receptor coactivator 2 (SRC2), which is known to play a vital role in GR-mediated repression of pro-inflammatory genes, was found to be dispensable for repression of glucocorticoid target genes sensitive to KDAC inhibition. At the promoters of these genes, KDAC inhibition did not result in altered nucleosome occupancy or histone H3 acetylation. Surprisingly, KDAC inhibition rapidly induced a significant decrease in H3K4Me2 at promoter nucleosomes with no corresponding change in H3K4Me3, suggesting the activation of the lysine demethylase, LSD1/KDM1A. Depletion of LSD1 expression via siRNA restored Dex-mediated repression in the presence of KDAC inhibitors, suggesting that LSD1 activation at these gene promoters is incompatible with transcriptional repression. Treatment with KDAC inhibitors does not alter cellular levels of LSD1 or its association with Dex-repressed gene promoters. Therefore, we conclude that Class I KDACs facilitate Dex-induced transcriptional repression by suppressing LSD1 complex activity at selected target gene promoters. Rather than facilitating repression of transcription, LSD1 opposes it in these gene contexts.