Molecular mechanisms of glucocorticoid action and resistance

Glucocorticoid Receptor Down-Regulation Affects Neural Stem Cell Proliferation and Hippocampal Neurogenesis

Dysregulation of the hypothalamic-pituitary-adrenal axis and abnormalities in the glucocorticoid receptor (GR) have been linked to major depressive disorder. Given the critical role of GR in stress response regulation, we investigated the impact of GR changes on neural stem cells (NSCs) proliferation and hippocampal neurogenesis. Stress response was induced using dexamethasone (DEX), a GR agonist, which led to reduced proliferation of neural stem cells and neural progenitor cells, as well as decreased expression of GR. Additionally, a reduction of serum concentration within the culture media resulted in suppressed cell proliferation, accompanied by decreased GR expression. The association between GR expression and cell proliferation was further confirmed through GR siRNA knockdown and overexpression experiments. Furthermore, in vivo studies utilizing young male C57BL/6 mice demonstrated that corticosterone (CORT) (35 μg/ml) administered through drinking water for four weeks induced depression-like behavior, as indicated by increased immobility times in forced swimming and tail suspension tests. CORT exposure led to reduced GR and nestin expression levels, along with diminished numbers of BrdU-positive cells in the hippocampi, indicating impaired hippocampal neurogenesis. Taken together, our findings provide the first evidence that stress-induced downregulation of GR negatively affects neurogenesis by inhibiting NSCs proliferation.

Fluocinolone Acetonide Implant for Uveitis: Dissecting Responder and Non-Responder Outcomes at a Tertiary Center

Macular edema (ME) remains a primary cause of visual deterioration in uveitis. Visual acuity (VA) can often be maintained using corticosteroid depot systems. This study evaluated the efficacy of a fluocinolone acetonide (FAc) intravitreal implant (ILUVIEN®) in treating non-infectious uveitis using real-world data. This retrospective analysis included 135 eyes subdivided into responders and non-responders. Central retinal thickness (CRT), VA, and intraocular pressure (IOP) were followed over time. A significant decrease in CRT and an increase in VA were observed in all eyes throughout the follow-up period (p < 0.01). An IOP increase (p = 0.028) necessitated treatment in 43% of eyes by Month 6. Non-responders were older (p = 0.004) and had been treated with more dexamethasone (DEX) implants (p = 0.04); 89.3% had a defect in the external limiting membrane (ELM) and inner/outer segment (IS/OS) zone (p < 0.001). Immunomodulatory therapy had no impact on treatment response. Pars plana vitrectomy (PPV) patients had a mean CRT reduction of 47.55 µm and a reduced effect by Month 24 (p = 0.046) versus non-PPV patients. We conclude that the FAc implant achieves long-term control of CRT and improves VA. Increases in IOP were manageable. Eyes with a previous PPV showed milder results. Data showed a correlation between older age, a damaged ELM and IS/OS zone, frequent DEX inserts, and poorer outcome measures.

Round Window Niche Veil is Visible on High-Resolution Computed Tomography and a Predictor of Local Drug Efficacy to Inner Ear

OBJECTIVES

To determine the morphologies and effect of the round window niche veil (RWNV) on local drug delivery efficacy and develop diagnostic criteria on high-resolution computed tomography (HRCT).

METHODS

Patients diagnosed with otosclerosis, bilateral profound sensorineural hearing loss or vestibular schwannoma were enrolled from 2019 to 2022, receiving temporal bone HRCT scanning, and anatomic variations of RWMV were summarized intraoperative. For patients with vestibular schwannoma, 1 mL of dexamethasone solution (4 mg/mL) was administered via facial recess during operation, and samples of perilymph were collected to analyze. The diagnostic criteria of RWNV on HRCT were developed and verified.

RESULTS

A total of 85 patients were enrolled. RWNV was observed in 54 cases intraoperatively with an incidence of 63.5% (95% CI, 52.9%-73.0%). The median perilymph concentrations were 4.86-fold higher in the group without RWNV than with RWNV (p < 0.0001). RWNV could be visualized on HRCT with a window width of 3500-4500 HU and a window level of 300-500 HU. The characteristic features were as follows: (1) a thin soft tissue shadow could be seen at the entrance of the round window niche (RWN); (2) it was visible in at least 2 consecutive layers along the upper margin of RWN from top to bottom; (3) it was discontinuous with the adjacent bone margin. The sensitivity and specificity of the diagnostic criteria were 77.8% and 93.6%, respectively.

CONCLUSION

RWNV could reduce local dexamethasone diffusion efficacy to the inner ear, which could be diagnosed on HRCT and used as a predictor of local drug delivery efficacy to the inner ear.

LEVEL OF EVIDENCE

3 Laryngoscope, 134:1396-1402, 2024.

Epigenetic programming mediates abnormal gut microbiota and disease susceptibility in offspring with prenatal dexamethasone exposure

Prenatal dexamethasone exposure (PDE) can lead to increased susceptibility to various diseases in adult offspring, but its effect on gut microbiota composition and the relationship with disease susceptibility remains unclear. In this study, we find sex-differential changes in the gut microbiota of 6-month-old infants with prenatal dexamethasone therapy (PDT) that persisted in female infants up to 2.5 years of age with altered bile acid metabolism. PDE female offspring rats show abnormal colonization and composition of gut microbiota and increased susceptibility to cholestatic liver injury. The aberrant gut microbiota colonization in the PDE offspring can be attributed to the inhibited Muc2 expression caused by decreased CDX2 expression before and after birth. Integrating animal and cell experiments, we further confirm that dexamethasone could inhibit Muc2 expression by activating GR/HDAC11 signaling and regulating CDX2 epigenetic modification. This study interprets abnormal gut microbiota and disease susceptibility in PDT offspring from intrauterine intestinal dysplasia.

The glucocorticoid receptor as a master regulator of the Müller cell response to diabetic conditions in mice

Diabetic retinopathy (DR) is considered a primarily microvascular complication of diabetes. Müller glia cells are at the centre of the retinal neurovascular unit and play a critical role in DR. We therefore investigated Müller cell-specific signalling pathways that are altered in DR to identify novel targets for gene therapy. Using a multi-omics approach on purified Müller cells from diabetic db/db mice, we found the mRNA and protein expression of the glucocorticoid receptor (GR) to be significantly decreased, while its target gene cluster was down-regulated. Further, oPOSSUM TF analysis and ATAC- sequencing identified the GR as a master regulator of Müller cell response to diabetic conditions. Cortisol not only increased GR phosphorylation. It also induced changes in the expression of known GR target genes in retinal explants. Finally, retinal functionality was improved by AAV-mediated overexpression of GR in Müller cells. Our study demonstrates an important role of the glial GR in DR and implies that therapeutic approaches targeting this signalling pathway should be aimed at increasing GR expression rather than the addition of more ligand.

Protective effects of ginseng and ginsenosides in the development of osteoarthritis (Review)

Osteoarthritis (OA) is a chronic inflammatory joint disease. Traditional chinese medicine provides a resource for drug screening for OA treatment. Ginseng and the associated bioactive compound, ginsenosides, may reduce inflammation, which is considered a risk factor for the development of OA. Specifically, ginsenosides may exhibit anti-inflammatory and anti-oxidative stress activities, and inhibit extracellular matrix degradation by suppressing the NF-κB and MAPK signaling pathways. Notably, specific ginsenosides, such as compound K and Rk1, may physically interact with IκB kinase and inhibit the associated phosphorylation. Thus, ginsenosides exhibit potential as therapeutic candidates in the management of OA. However, the low water solubility limits the clinical applications of ginsenosides. Numerous effective strategies have been explored to improve bioavailability; however, further investigations are still required.

Inflammation in the pathogenesis of depression: a disorder of neuroimmune origin

There are several hypotheses concerning the underlying pathophysiological mechanisms of major depression, which centre largely around adaptive changes in neuronal transmission and plasticity, neurogenesis, and circuit and regional connectivity. The immune and endocrine systems are commonly implicated in driving these changes. An intricate interaction of stress hormones, innate immune cells and the actions of soluble mediators of immunity within the nervous system is described as being associated with the symptoms of depression. Bridging endocrine and immune processes to neurotransmission and signalling within key cortical and limbic brain circuits are critical to understanding depression as a disorder of neuroimmune origins. Emergent areas of research include a growing recognition of the adaptive immune system, advances in neuroimaging techniques and mechanistic insights gained from transgenic animals. Elucidation of glial-neuronal interactions is providing additional avenues into promising areas of research, the development of clinically relevant disease models and the discovery of novel therapies. This narrative review focuses on molecular and cellular mechanisms that are influenced by inflammation and stress. The aim of this review is to provide an overview of our current understanding of depression as a disorder of neuroimmune origin, focusing on neuroendocrine and neuroimmune dysregulation in depression pathophysiology. Advances in current understanding lie in pursuit of relevant biomarkers, as the potential of biomarker signatures to improve clinical outcomes is yet to be fully realised. Further investigations to expand biomarker panels including integration with neuroimaging, utilising individual symptoms to stratify patients into more homogenous subpopulations and targeting the immune system for new treatment approaches will help to address current unmet clinical need.

Effects of different doses of methylprednisolone therapy on acute respiratory distress syndrome: results from animal and clinical studies

Background

The optimal dose of glucocorticoids for acute respiratory distress syndrome (ARDS) is uncertain. This study aimed to evaluate the effects of different doses of methylprednisolone on sepsis-induced acute lung injury (ALI) rats and a cohort of moderate and severe ARDS patients.

Methods

ALI rats, challenged with lipopolysaccharide, were randomly received intraperitoneal injection of normal saline (model group) and different doses of methylprednisolone (0.5, 2, 8 mg/kg, named as low-, moderate- and high-dose group, respectively) for 5 days. The body weight changes of rats, inflammatory factors in bronchoalveolar lavage fluid (BALF), lung wet/dry ratio, histopathological score, and the mRNA expressions of glucocorticoid receptor α (GRα), GRβ and nuclear factor-κB (NF-κB) were measured. Forty moderate and severe ARDS patients were treated with standard of care or plus different doses of methylprednisolone (40, 80, 120 mg/day, named as low-, moderate- and high-dose group, respectively) for 5 days. Clinical outcomes were PaO₂/FiO₂ ratio and C-reactive protein (CRP) level at day 5, intubation rate, hospital stay, 28-day mortality, and adverse events rate.

Results

In animal experiment, different doses of methylprednisolone could increase the body weight of rats, and reduce inflammatory factors in BALF and the degree of lung injury compared with model group. The efficacy of methylprednisolone at moderate-dose was better than that at low-dose, but was equivalent to that at high-dose, which was consistent with the differential changes in the mRNA expression of GRα, GRβ and NF-κB. In clinical study, the moderate-dose group was associated with higher PaO₂/FiO₂ ratio and lower CRP level. No significant difference in other clinical outcomes among groups was detected.

Conclusions

This study showed that the efficacy of methylprednisolone in ARDS treatment was not always dose-dependent due to the differential regulation of related receptors. The moderate-dose of methylprednisolone may be the potential optimal dose for ARDS treatment, which needs to be further verified by larger clinical trials.

Basis for diurnal exacerbation of neuropathic pain hypersensitivity and its application for drug development

In addition to diurnal rhythms in physiology and behavior, a variety of pathological conditions also exhibit marked day-night changes in symptom intensity, exemplified by allergic rhinitis, arthritis, asthma, myocardial infarction, congestive heart failure, stroke, and chronic pain disorders. Currently, novel therapeutic approaches are facilitated by the development of chemical compounds targeted to key proteins that cause diurnal exacerbation of pathological events. Neuropathic pain is a chronic condition that occurs by tumor-induced nerve compression, cancer cell infiltration into the nerve, diabetes, and herpes virus infection. One troublesome hallmark symptom of neuropathic pain is hypersensitivity to normally innocuous stimuli known as "mechanical allodynia" that is often refractory to common analgesic therapies. Millions of patients worldwide presently endure neuropathic pain. We summarize the recent insights gained into the mechanism of diurnal exacerbation of neuropathic pain hypersensitivity and introduce the strategy of circadian clock-based drug development.

Homeostatic Regulation of Glucocorticoid Receptor Activity by Hypoxia-Inducible Factor 1: From Physiology to Clinic

Glucocorticoids (GCs) represent a well-known class of lipophilic steroid hormones biosynthesised, with a circadian rhythm, by the adrenal glands in humans and by the inter-renal tissue in teleost fish (e.g., zebrafish). GCs play a key role in the regulation of numerous physiological processes, including inflammation, glucose, lipid, protein metabolism and stress response. This is achieved through binding to their cognate receptor, GR, which functions as a ligand-activated transcription factor. Due to their potent anti-inflammatory and immune-suppressive action, synthetic GCs are broadly used for treating pathological disorders that are very often linked to hypoxia (e.g., rheumatoid arthritis, inflammatory, allergic, infectious, and autoimmune diseases, among others) as well as to prevent graft rejections and against immune system malignancies. However, due to the presence of adverse effects and GC resistance their therapeutic benefits are limited in patients chronically treated with steroids. For this reason, understanding how to fine-tune GR activity is crucial in the search for novel therapeutic strategies aimed at reducing GC-related side effects and effectively restoring homeostasis. Recent research has uncovered novel mechanisms that inhibit GR function, thereby causing glucocorticoid resistance, and has produced some surprising new findings. In this review we analyse these mechanisms and focus on the crosstalk between GR and HIF signalling. Indeed, its comprehension may provide new routes to develop novel therapeutic targets for effectively treating immune and inflammatory response and to simultaneously facilitate the development of innovative GCs with a better benefits-risk ratio.

Acquired Glucocorticoid Resistance Due to Homologous Glucocorticoid Receptor Downregulation: A Modern Look at an Age-Old Problem

For over 70 years, the unique anti-inflammatory properties of glucocorticoids (GCs), which mediate their effects via the ligand-activated transcription factor, the glucocorticoid receptor alpha (GRα), have allowed for the use of these steroid hormones in the treatment of various autoimmune and inflammatory-linked diseases. However, aside from the onset of severe side-effects, chronic GC therapy often leads to the ligand-mediated downregulation of the GRα which, in turn, leads to a decrease in GC sensitivity, and effectively, the development of acquired GC resistance. Although the ligand-mediated downregulation of GRα is well documented, the precise factors which influence this process are not well understood and, thus, the development of an acquired GC resistance presents an ever-increasing challenge to the pharmaceutical industry. Recently, however, studies have correlated the dimerization status of the GRα with its ligand-mediated downregulation. Therefore, the current review will be discussing the major role-players in the homologous downregulation of the GRα pool, with a specific focus on previously reported GC-mediated reductions in GRα mRNA and protein levels, the molecular mechanisms through which the GRα functional pool is maintained and the possible impact of receptor conformation on GC-mediated GRα downregulation.

Lycii radicis cortex inhibits glucocorticoid‑induced bone loss by downregulating Runx2 and BMP‑2 expression

Lycii radicis cortex (LRC) has been used to regulate high blood pressure, body temperature, pain and bone disorders in East Asia. Glucocorticoids (GCs), also known as steroids, are potent immunity regulators widely used in the treatment of inflammatory diseases. However, despite their effectiveness, GC usage is strictly controlled due to severe side‑effects, such as osteoporosis. However, further research is required as to date, at least to the best of our knowledge, there is no appropriate model to overcome secondary osteoporosis as a side‑effect of GC use. Thus, the aim of the present study was to establish an experimental model of osteoporosis induced by GC. Furthermore, the present study aimed to establish the research methodology for medical evaluations of the effectiveness and side‑effects of GCs. A secondary osteoporosis animal model was established, and the animals were divided into two groups as follows: The allergic contact dermatitis (ACD)‑induced group and the non‑ACD‑induced group. In the ACD‑induced group, a GC topical application group was compared with a GC subcutaneous injection group. The results revealed that the presence of ACD affected the induction of GC‑mediated osteoporosis. Therefore, the group exhibiting induced ACD that was treated with a topical application of GC was selected for examining the side‑effects of GCs. The effects of LRC on secondary osteoporosis were confirmed in vivo and in vitro. The results indicated that LRC regulated dexamethasone‑induced osteoblast apoptotic markers, including caspase‑6, caspase‑9, X‑linked inhibitor of apoptosis, apoptosis inhibitor 1 and apoptosis inhibitor 2, and increased the expression of osteoblast differentiation‑related genes, such as Runt‑related transcription factor 2 and bone morphogenetic protein 2 in the MC3T3E‑1 cell line. LRC also significantly reduced GC‑induced osteoporosis and exerted anti‑inflammatory effects in vivo. In addition, LRC inhibited the reduction of calbindin‑D28k in the kidney. Overall, the results of the present study suggest that the use of LRC alleviates GC‑induced secondary osteoporosis.

A new model for the HPA axis explains dysregulation of stress hormones on the timescale of weeks

Stress activates a complex network of hormones known as the hypothalamic-pituitary-adrenal (HPA) axis. The HPA axis is dysregulated in chronic stress and psychiatric disorders, but the origin of this dysregulation is unclear and cannot be explained by current HPA models. To address this, we developed a mathematical model for the HPA axis that incorporates changes in the total functional mass of the HPA hormone-secreting glands. The mass changes are caused by HPA hormones which act as growth factors for the glands in the axis. We find that the HPA axis shows the property of dynamical compensation, where gland masses adjust over weeks to buffer variation in physiological parameters. These mass changes explain the experimental findings on dysregulation of cortisol and ACTH dynamics in alcoholism, anorexia, and postpartum. Dysregulation occurs for a wide range of parameters and is exacerbated by impaired glucocorticoid receptor (GR) feedback, providing an explanation for the implication of GR in mood disorders. These findings suggest that gland-mass dynamics may play an important role in the pathophysiology of stress-related disorders.

Gender May Influence the Immunosuppressive Actions of Prednisone in Young Patients With Inflammatory Bowel Disease

Although the use of glucocorticoids (GC) is well established, the therapeutic response to these agents often shows important interindividual differences, in particular among young patients with inflammatory bowel diseases (IBD). Currently, GC resistance or dependence cannot be predicted by clinical or laboratory findings. The aim of this study was to investigate the association of gender and age with GC efficacy and with the expression of Glucocorticoid-Induced Leucine Zipper (GILZ). One hundred thirty patients (mean age at enrolment 12.6 years, 53 Crohn’s disease, 70 males) were enrolled in this retrospective study. IBD patients with active disease despite prednisone at a daily dose of up to 2 mg/kg over a period of 4 weeks were defined as steroid resistant. Patients who initially responded but relapsed upon dose reduction were considered steroid-dependent. Total RNA was extracted from biopsies of 14 patients (9 males) and the levels of GILZ mRNA were evaluated by real-time PCR. Association between clinical response to prednisone and the considered demographic variables was evaluated using logistic regression models. After 4 weeks of treatment, 112 patients were responders to prednisone and 18 were resistant; at this time-point, resistant patients were older than responders (p=0.032). After 12 weeks, 42, 71 and 12 patients were sensitive, dependent and resistant respectively; at this time-point, females were more prone than males to develop prednisone dependence vs a good response (p=0.028) while age had no effect. Age was associated with response both at 4 and 12 weeks in the subgroups of females: resistant patients were older than sensitive ones at 4 weeks (p=0.02). Likewise, at 12 weeks of therapy, dependent patients resulted older than sensitive ones (p=0.05). No association of age with prednisone response was found in males. In a subgroup of 14 patients (5 females), GILZ mRNA expression in intestinal biopsies was higher in males (p=0.0031). Patients with unfavorable response (7) presented lower GILZ expression at disease onset in comparison to the responder group (p=0.017). Older females with IBD have a higher incidence of prednisone unfavorable response and reduced intestinal expression of the GC pharmacodynamic marker GILZ.

Ozone-Induced Oxidative Stress, Neutrophilic Airway Inflammation, and Glucocorticoid Resistance in Asthma

Despite recent advances in using biologicals that target Th2 pathways, glucocorticoids form the mainstay of asthma treatment. Asthma morbidity and mortality remain high due to the wide variability of treatment responsiveness and complex clinical phenotypes driven by distinct underlying mechanisms. Emerging evidence suggests that inhalation of the toxic air pollutant, ozone, worsens asthma by impairing glucocorticoid responsiveness. This review discusses the role of oxidative stress in glucocorticoid resistance in asthma. The underlying mechanisms point to a central role of oxidative stress pathways. The primary data source for this review consisted of peer-reviewed publications on the impact of ozone on airway inflammation and glucocorticoid responsiveness indexed in PubMed. Our main search strategy focused on cross-referencing "asthma and glucocorticoid resistance" against "ozone, oxidative stress, alarmins, innate lymphoid, NK and γδ T cells, dendritic cells and alveolar type II epithelial cells, glucocorticoid receptor and transcription factors". Recent work was placed in the context from articles in the last 10 years and older seminal research papers and comprehensive reviews. We excluded papers that did not focus on respiratory injury in the setting of oxidative stress. The pathways discussed here have however wide clinical implications to pathologies associated with inflammation and oxidative stress and in which glucocorticoid treatment is essential.

The Mechanisms Underlying Autonomous Adrenocorticotropic Hormone Secretion in Cushing's Disease

Cushing’s disease caused due to adrenocorticotropic hormone (ACTH)-secreting pituitary adenomas (ACTHomas) leads to hypercortisolemia, resulting in increased morbidity and mortality. Autonomous ACTH secretion is attributed to the impaired glucocorticoid negative feedback (glucocorticoid resistance) response. Interestingly, other conditions, such as ectopic ACTH syndrome (EAS) and non-neoplastic hypercortisolemia (NNH, also known as pseudo-Cushing’s syndrome) also exhibit glucocorticoid resistance. Therefore, to differentiate between these conditions, several dynamic tests, including those with desmopressin (DDAVP), corticotrophin-releasing hormone (CRH), and Dex/CRH have been developed. In normal pituitary corticotrophs, ACTH synthesis and secretion are regulated mainly by CRH and glucocorticoids, which are the ACTH secretion-stimulating and -suppressing factors, respectively. These factors regulate ACTH synthesis and secretion through genomic and non-genomic mechanisms. Conversely, glucocorticoid negative feedback is impaired in ACTHomas, which could be due to the overexpression of 11β-HSD2, HSP90, or TR4, or loss of expression of CABLES1 or nuclear BRG1 proteins. Genetic analysis has indicated the involvement of several genes in the etiology of ACTHomas, including USP8, USP48, BRAF, and TP53. However, the association between glucocorticoid resistance and these genes remains unclear. Here, we review the clinical aspects and molecular mechanisms of ACTHomas and compare them to those of other related conditions.

Latest perspectives on glucocorticoid-induced apoptosis and resistance in lymphoid malignancies

Glucocorticoids are essential drugs in the treatment protocols of lymphoid malignancies. These steroidal hormones trigger apoptosis of the malignant cells by binding to the glucocorticoid receptor (GR), which is a member of the nuclear receptor superfamily. Long term glucocorticoid treatment is limited by two major problems: the development of glucocorticoid-related side effects, which hampers patient quality of life, and the emergence of glucocorticoid resistance, which is a gradual process that is inevitable in many patients. This emphasizes the need to reevaluate and optimize the widespread use of glucocorticoids in lymphoid malignancies. To achieve this goal, a deep understanding of the mechanisms governing glucocorticoid responsiveness is required, yet, a recent comprehensive overview is currently lacking. In this review, we examine how glucocorticoids mediate apoptosis by detailing GR's genomic and non-genomic action mechanisms in lymphoid malignancies. We continue with a discussion of the glucocorticoid-related problems and how these are intertwined with one another. We further zoom in on glucocorticoid resistance by critically analyzing the plethora of proposed mechanisms and highlighting therapeutic opportunities that emerge from these studies. In conclusion, early detection of glucocorticoid resistance in patients remains an important challenge as this would result in a timelier treatment reorientation and reduced glucocorticoid-instigated side effects.

Effect of corticosteroid (triamcinolone acetonide) and chlorhexidin on chemotherapy- induced oxidative stress in buccal mucosa of rats

Oral mucositis (OM) refers to erythematous and ulcerative lesions of the oral mucosa. This pathology can occur by various causes. Cancer therapy is one of the well-known causes of OM such as chemotherapy and/or with radiation therapy. It has been widely mentioned that oxidative stress parameters such as lipid peroxidation (LP) levels increase during cancer process. Glutathione (GSH) is one of the major intracellular enzymes to detoxify oxidant molecules. The aim of this study was to investigate and compare the effects of Triamcinolone Acetonide (TA), a synthetic steroid chlorhexidine (CHX), a chemical antiseptic, on 5- fluorouracil (5-FU), a chemotherapeutic agent and soft abrasion induced OM in buccal mucosa of rats.OM was induced in rats through a combination of 5-FU treatment and mild abrasion of the cheek pouch with a wire brush. Buccal mucosa lipid peroxidation (LP) levels were higher (p< 0.05) in 5-FU group than in control although LP levels were lower (p<0.05) in TA group than in control group. The reduced glutathione levels were lower (p<0.05) in 5-FU group than in the control group although its level was higher (p<0.05) in TA and CHX groups than in the 5-FU group. Glutathione peroxidase activity was also higher (p<0.05) in TA group than the 5- FU group. In histopathological analyses, treatment with TA reduced 5-FU induced inflammatory cell infiltration and ulceration (p<0.001) but not with CHX.In conclusion, we observed that TA and CHX treatment modulated chemotherapy induced oxidative injury in the rat OM. However, only TA histopathologically ameliorated the 5-FU induced OM of rats. These findings suggest that TA is a useful agent for management of experimental oxidative injury and OM caused by the chemotherapy.

Stress, glucocorticoid signaling pathway, and metabolic disorders

BACKGROUND AND AIMS

Glucocorticoids and the GR serve as an essential molecular mediator of stress and different physiologic processes. This review summarizes main findings from studies on the role of the GC/GR signaling in the modulation of genes for nutrient processing by the different organs involved in metabolic diseases.

METHODS

Descriptive review of relevant papers known to the author was conducted.

RESULTS

Several high-throughput screenings in the past 15 years have identified potential GR DNA-binding regions in different cell types with genes that are annotated to be important for the control of metabolism. Transcriptional regulation of these GC-responsive genes provides links between the hypothalamic-pituitary-adrenal axis (HPA) and systemic energy homeostasis in both physiological and pathophysiological states. Future studies must reconsider the use of agonist, the utilization of animal models of stress and metabolic disorders, and validation in humans.

CONCLUSION

This review recapitulates the significant role of the GC/GR signaling in molecular metabolic control and metabolic disorders. Potential future research focus and optimizations have also been identified.

[Corticosteroid-induced diabetes: Novelties in pathophysiology and management]

Diabetes frequently occurs during corticosteroid treatment, sometimes necessitating urgent therapeutic management, with insulin for example. Corticosteroids induce insulin resistance in the liver, adipocytes and skeletal muscle, and have direct deleterious effects on insulin secretion. The development of insulin resistance during corticosteroid treatment, and the insufficient adaptation of insulin secretion, are key elements in the pathophysiology of corticosteroid-induced diabetes. The capacity of pancreatic β-cells to increase insulin secretion in response to insulin resistance is partly genetically determined. A familial history of type 2 diabetes is, therefore, a major risk factor for diabetes development on corticosteroid treatment. Corticosteroid treatments are usually initiated at a fairly high dose, which is subsequently decreased to the lowest level sufficient to achieve disease control. Pharmacological management of diabetes is needed in patients with blood glucose levels exceeding 2.16 g/l (12 mmol/l) and insulin therapy can be started when blood glucose levels are higher than 3.6 g/l (20 mmol/l) with clinical symptoms of diabetes. Insulin can then be replaced with oral hypoglycemic compounds when both blood glucose levels and corticosteroid dose have decreased. Patient education is essential, particularly for the management of hypoglycemia when corticosteroids are withdrawn or their dose tapered.

Epigenetic repression of AT2 receptor is involved in β cell dysfunction and glucose intolerance of adult female offspring rats exposed to dexamethasone prenatally

Prenatal exposure to dexamethasone (PDE) impairs pancreatic β cell development and glucose homeostasis in offspring especially females. To explore the underlying intrauterine programming mechanism, pregnant Wistar rats were subcutaneously administered with dexamethasone (0, 0.2 and 0.8 mg/kg·d) from gestational days (GD) 9 to 20. Female offspring were collected on GD20 (fetus) and in postnatal week 28 (adult), respectively. PDE reduced the serum insulin levels, β cell mass, and pancreatic insulin expressions in fetuses and adults, causing glucose intolerance after maturity. The persistent suppression of pancreatic angiotensin II receptor type 2 (AT2R) expression before and after birth could be observed in the PDE females, which is accompanied with decreased histone 3 lysine 14 acetylation (H3K14ac) and H3K27ac levels in AT2R promoter. PDE increased the gene expressions of glucocorticoid receptor (GR) and histone deacetylase 2 (HDAC2) in fetal pancreas. Furthermore, dexamethasone inhibited insulin biosynthesis while activated GR and HDAC2 expression in the rat INS-1 cells. The AT2R expression was repressed by dexamethasone in vitro but only H3K27ac levels in AT2R promoter were lowered. Dexamethasone enhanced the interaction between GR and HDAC2 proteins as well as the binding of GR/HDAC2 complex to AT2R promoter. Moreover, overexpression of AT2R could restore the suppressed insulin biosynthesis induced by dexamethasone in vitro, and both GR antagonist and histone deacetylase abolished the decreased H3K27ac level and gene expression of AT2R. In conclusion, continuous epigenetic repression of AT2R before and after birth may be involved in β cell dysfunction and glucose intolerance of the PDE adult female offspring.

Modeling Pathway Dynamics of the Skeletal Muscle Response to Intravenous Methylprednisolone (MPL) Administration in Rats: Dosing and Tissue Effects

A model-based approach for the assessment of pathway dynamics is explored to characterize metabolic and signaling pathway activity changes characteristic of the dosing-dependent differences in response to methylprednisolone in muscle. To consistently compare dosing-induced changes we extend the principles of pharmacokinetics and pharmacodynamics and introduce a novel representation of pathway-level dynamic models of activity regulation. We hypothesize the emergence of dosing-dependent regulatory interactions is critical to understanding the mechanistic implications of MPL dosing in muscle. Our results indicate that key pathways, including amino acid and lipid metabolism, signal transduction, endocrine regulation, regulation of cellular functions including growth, death, motility, transport, protein degradation, and catabolism are dependent on dosing, exhibiting diverse dynamics depending on whether the drug is administered acutely of continuously. Therefore, the dynamics of drug presentation offer the possibility for the emergence of dosing-dependent models of regulation. Finally, we compared acute and chronic MPL response in muscle with liver. The comparison revealed systematic response differences between the two tissues, notably that muscle appears more prone to adapt to MPL.

Choroidal Thickness After Dexamethasone Implant or Aflibercept in Patients with Diabetic Macular Edema Persistent to Ranibizumab

Purpose: This study aims to compare subfoveal choroidal thicknesses (SFCTs) after intravitreal dexamethasone (IVD) or intravitreal aflibercept (IVA) treatment in patients with persistent diabetic macular edema (DME) unresponsive to intravitreal ranibizumab (IVR). Methods: The study consisted of patients with DME unresponsive to IVR treatment in which 37 were administered 1 dose IVD (group A) and 34 patients who were administered 3 doses of IVA (group B), as well as 35 healthy individuals (group C). Detailed ophthalmological examination and optical coherence tomography parameters of group A and group B, including central retinal thickness and SFCT, were retrospectively evaluated before and after treatment. Results from preinjection, and 1, 2, and 3 months after injection were analyzed. Results of group A and group B were compared within themselves and also compared with group C. Results: SFCT measurements were compared within group A and group B (1 = preinjection; 2 = 1 month postinjection; 3 = 2 months postinjection; 4 = 3 months postinjection). There was significant thinning in SFCT between 1-2, 1-3, 1-4, 2-3, 2-4, and 3-4 time intervals within both group A and group B (both P < 0.001). Comparison of SFCT measurements showed preinjection, 1-, and 2-month values of group A were significantly thicker than those of group C (P < 0.001), whereas there was no significant difference between 3-month values (P = 0.09). Preinjection, 1-, and 2-month values of group B were significantly thicker than those of group C (P < 0.001), whereas there was no significant difference between 3-month values (P = 0.06). Conclusions: Three month follow-up showed thinning in SFCT measurements in patients with persistent DME unresponsive to IVR who were applied IVD or IVA treatment.

Glucocorticoid Receptor Polymorphisms Influence Muscle Strength in Cushing's Syndrome

CONTEXT

An important clinical feature of Cushing's syndrome (CS) is proximal muscle myopathy caused by glucocorticoid induced protein metabolism. However, interindividual differences cannot be explained solely by the pure extent of hypercortisolemia.

OBJECTIVE

To evaluate the effects of glucocorticoid receptor (GR) polymorphisms (BclI, N363S, ER22/23EK and A3669G), which influence peripheral glucocorticoid sensitivity on muscular function in endogenous CS.

METHODS

205 patients with proven endogenous CS (128 central, 77 adrenal) from 3 centers of the German Cushing's Registry and 125 subjects, in whom CS was ruled out, were included. All subjects were assessed for grip strength (via hand grip dynamometer) and performed a chair-rising test (CRT). DNA samples were obtained from peripheral blood leukocytes for GR genotyping.

RESULTS

In patients with active CS, normalized handgrip strength of the dominant and nondominant hand was higher in A3669G minor allele than in wildtype carriers (P = .006 and P = .021, respectively). CS patients in remission and ruled-out CS showed no differences in handgrip strength regarding A3669G minor allele and wildtype carriers. Male CS patients harboring the ER22/23EK wildtype presented lower hand grip strength than minor allele carriers (P = .049 dominant hand; P = .027 nondominant hand). The other polymorphisms did not influence handgrip strength. CRT showed no differences regarding GR polymorphisms carrier status.

CONCLUSION

Handgrip strength seems to be more susceptible to hypercortisolism in A3669G wildtype than in A3669G minor allele carriers. This might partially explain the inter-individual differences of glucocorticoid-induced myopathy in patients with endogenous CS. ER22/23EK polymorphism seems to exert sex-specific differences.

The role of Müller cell glucocorticoid signaling in diabetic retinopathy

Diabetic retinopathy (DR) is a sight-threatening complication associated with the highly prevalent diabetes disorder. Both the microvascular damage and neurodegeneration detected in the retina caused by chronic hyperglycemia have brought special attention to Müller cells, the major macroglia of the retina that are responsible for retinal homeostasis. Given the role of glucocorticoid signaling in anti-inflammatory responses and the almost exclusive expression of glucocorticoid receptors (GRs) in retinal Müller cells, administration of corticosteroid agonists as a potential treatment option has been widely studied. Although these approaches have been moderately efficacious in treating or de-escalating DR pathomechanisms, there are various side effects and gaps of knowledge with regard to introducing exogenous glucocorticoids to the diseased retina. In this paper, we provide a review of the literature concerning the available evidence for the role of Müller cell glucocorticoid signaling in DR and we discuss previously investigated approaches in modulating this system as possible treatment options. Furthermore, we propose a novel alternative to the available choices of treatment by using gene therapy as a tool to regulate the expression of GR in retinal Müller cells. Upregulating GR expression allows for induced glucocorticoid signaling with more enduring effects compared to injection of agonists. Hence, repetitive injections would no longer be required. Lastly, side effects of glucocorticoid therapy such as glucocorticoid resistance of GR following chronic exposure to excess ligands or agonists can be avoided.

Mitochondrial dysfunction increases pro-inflammatory cytokine production and impairs repair and corticosteroid responsiveness in lung epithelium

COPD is characterized by chronic lung inflammation and irreversible lung tissue damage. Inhaled noxious gases, including cigarette smoke, are the major risk factor for COPD. Inhaled smoke first encounters the epithelial lining of the lungs, causing oxidative stress and mitochondrial dysfunction. We investigated whether a mitochondrial defect may contribute to increased lung epithelial pro-inflammatory responses, impaired epithelial repair and reduced corticosteroid sensitivity as observed in COPD. We used wild-type alveolar epithelial cells A549 and mitochondrial DNA-depleted A549 cells (A549 Rho-0) and studied pro-inflammatory responses using (multiplex) ELISA as well as epithelial barrier function and repair (real-time impedance measurements), in the presence and absence of the inhaled corticosteroid budesonide. We observed that A549 Rho-0 cells secrete higher levels of pro-inflammatory cytokines than wild-type A549 cells and display impaired repair upon wounding. Budesonide strongly suppressed the production of neutrophil attractant CXCL8, and promoted epithelial integrity in A549 wild-type cells, while A549 Rho-0 cells displayed reduced corticosteroid sensitivity compared to wild-type cells. The reduced corticosteroid responsiveness may be mediated by glycolytic reprogramming, specifically glycolysis-associated PI3K signaling, as PI3K inhibitor LY294002 restored the sensitivity of CXCL8 secretion to corticosteroids in A549 Rho-0 cells. In conclusion, mitochondrial defects may lead to increased lung epithelial pro-inflammatory responses, reduced epithelial repair and reduced corticosteroid responsiveness in lung epithelium, thus potentially contributing to the pathogenesis of COPD.

Cytokine Profile, Apoptosis, Glucocorticoid Receptor, and P-glycoprotein Expression Before and After Megadose Methylprednisolone Treatment in Children With Acute Immune Thrombocytopenia

OBJECTIVE

Immune thrombocytopenia (ITP) is an autoimmune disease, and it has become evident that T lymphocytes play an important role in the pathogenesis of ITP. We investigated the role of T helper (Th) intracellular IL-2, IL-4, IL-6, IFN-γ, and T lymphocyte apoptosis in the pathogenesis of acute ITP and the effect of glucocorticoid treatment on cytokine profile. We investigated also P-glycoprotein (P-gp) and glucocorticoid receptor (GCR) expression as a possible mechanism for glucocorticoid resistance.

MATERIAL AND METHODS

The study includes 20 children with acute ITP having a platelet count <20,000/mm and 20 healthy children as a control group. Patients with acute ITP were treated with megadose methylprednisolone (MDMP) (MDMP in the dose of 30 mg/kg/d between day 1 and 3 and 20 mg/kg/d between day 4 and 7). Th intracellular IL2, IL-4, IL-6, and IFN-γ percentages, T-cell P-gp expression, T-cell and monocyte GCR expression, and T-cell apoptosis were evaluated before and after treatment in acute ITP patients and in the control group.

RESULTS

Acute ITP patients had significantly higher Th IL-2, IL-4, IL-6, and IFN-γ percentages compared with the control group (P<0.05). Th IL-2 and IFN-γ percentages were significantly lowered with MDMP treatment (P<0.05). IFN-γ/IL-4 ratio was also lowered with the MDMP treatment (P<0.05). T-lymphocyte P-gp expression and T lymphocyte and monocyte GCR expression were all similar between acute ITP pretreatment and control groups (P>0.05). T-lymphocyte P-gp expression was higher in the posttreatment group than in the pretreatment group (P<0.05). Both T lymphocyte and monocyte GCR expression percentages were not different in the pretreatment and posttreatment groups (P>0.05). Early apoptosis in T lymphocytes was significantly lower in the pretreatment acute ITP group than in the control group (P<0.05). Necrotic apoptosis in T lymphocytes was significantly increased with MDMP treatment (P<0.05).

CONCLUSIONS

Th1 and Th2 cytokine profile is observed in acute ITP pathogenesis, and MDMP treatment causes Th1 to Th2 cytokine profile shift and induction of T-lymphocyte apoptosis. There is a need to have a greater number of resistant cases in order to better evaluate the P-gp and GCR expression in glucocorticoid resistance in acute ITP.

Regulatory Effect of Resveratrol and Prednisolone on MDR1 Protein Expression in Acute Lymphoblastic Leukemia Cell Line (CCRF-CEM)

Objective:

Chemotherapy is the most widely recognized technique to regard leukemia and also different sorts of human tumors. In any case, tranquilize protection has stayed as the primary test against the adequacy of medications. Besides, having different unfriendly impacts, chemotherapy drugs are getting to be traded by characteristic modalities for growth treatment. In such manner, natural segments, for example, resveratrol and prednisolone have been recognized to sharpen the leukemic cells to modified cell demise through an arrangement of complex procedures. In this investigation, we have analyzed effect of 15, 50 and 100μM of resveratrol and 700μM of prednisolone on the human multidrug protection quality 1 (MDR1) as a notable marker for cell sedate protection. We assessed the impact of resveratrol and prednisolone on MDR1 protein expression in the CCRF-CEM cell line as an agent for intense lymphoblastic leukemia. The investigation was planned to clear up whether.

Materials and methods:

CCRF-CEM cells linage get under drug treatment with use of resveratrol and prednisolone. Western blot use at 24 and 48 hours with different doses of resveratrol and prednisolone to analysis of MDR1 expression changes.

Results:

Effect of 15, 50, and 100 micro molar of resveratrol and 700 micro molars of prednisolone on CCRF-CEM cells led to the MDR1 decrease. Western blot use for evaluation of MDR1 protein expression changes.

Conclusion:

In the present study, we observed that resveratrol and prednisolone, with a dose-dependent effect, can reduce the expression of the MDR1 protein. This reduction of expression demonstrates that resveratrol and prednisolone can overcome to drug resistance created by MDR1.

Pathway-Based Analysis of the Liver Response to Intravenous Methylprednisolone Administration in Rats: Acute Versus Chronic Dosing

Pharmacological time-series data, from comparative dosing studies, are critical to characterizing drug effects. Reconciling the data from multiple studies is inevitably difficult; multiple in vivo high-throughput -omics studies are necessary to capture the global and temporal effects of the drug, but these experiments, though analogous, differ in (microarray or other) platforms, time-scales, and dosing regimens and thus cannot be directly combined or compared. This investigation addresses this reconciliation issue with a meta-analysis technique aimed at assessing the intrinsic activity at the pathway level. The purpose of this is to characterize the dosing effects of methylprednisolone (MPL), a widely used anti-inflammatory and immunosuppressive corticosteroid (CS), within the liver. A multivariate decomposition approach is applied to analyze acute and chronic MPL dosing in male adrenalectomized rats and characterize the dosing-dependent differences in the dynamic response of MPL-responsive signaling and metabolic pathways. We demonstrate how to deconstruct signaling and metabolic pathways into their constituent pathway activities, activities which are scored for intrinsic pathway activity. Dosing-induced changes in the dynamics of pathway activities are compared using a model-based assessment of pathway dynamics, extending the principles of pharmacokinetics/pharmacodynamics (PKPD) to describe pathway activities. The model-based approach enabled us to hypothesize on the likely emergence (or disappearance) of indirect dosing-dependent regulatory interactions, pointing to likely mechanistic implications of dosing of MPL transcriptional regulation. Both acute and chronic MPL administration induced a strong core of activity within pathway families including the following: lipid metabolism, amino acid metabolism, carbohydrate metabolism, metabolism of cofactors and vitamins, regulation of essential organelles, and xenobiotic metabolism pathway families. Pathway activities alter between acute and chronic dosing, indicating that MPL response is dosing dependent. Furthermore, because multiple pathway activities are dominant within a single pathway, we observe that pathways cannot be defined by a single response. Instead, pathways are defined by multiple, complex, and temporally related activities corresponding to different subgroups of genes within each pathway.

Intestinal glucocorticoid synthesis enzymes in pediatric inflammatory bowel disease patients

Inflammatory bowel disease (IBD), such as Crohn's disease and ulcerative colitis are devastating chronic immunopathologies of the intestinal mucosa, which are frequently treated by immunosuppressive glucocorticoids. Endogenous glucocorticoids are not only produced by the adrenal glands, but also by the intestinal epithelium. Local glucocorticoid synthesis critically contributes to the immune homeostasis of the intestinal mucosa. As defective intestinal glucocorticoid synthesis has been associated with the development of IBD, we investigated the expression of steroidogenic enzymes and the key transcriptional regulator Liver Receptor Homolog-1 (LRH-1/NR5A2) in ileal and colonic biopsies human pediatric IBD and control patients. Furthermore, the induction of steroidogenic enzymes and their transcriptional regulation by LRH-1 was investigated in a mouse model of experimental colitis. These analyses revealed that colitis-induced expression of steroidogenic enzymes in the murine colon is dependent on the presence of LRH-1, as intestinal deletion of LRH-1 strongly reduced their colitis-induced expression. Similarly, a strong correlation between the expression of LRH-1 and different steroidogenic enzymes was seen in intestinal biopsies of human pediatric patients. Importantly, reduced expression of hydroxysteroid dehydrogenase 11B1 (HSD11B1) was observed in IBD patients compared to control patients, suggesting that defective local reactivation of glucocorticoids could contribute to the pathogenesis of IBD.

Disease- and treatment-associated acquired glucocorticoid resistance

The development of resistance to glucocorticoids (GCs) in therapeutic regimens poses a major threat. Generally, GC resistance is congenital or acquired over time as a result of disease progression, prolonged GC treatment or, in some cases, both. Essentially, disruptions in the function and/or pool of the glucocorticoid receptor α (GRα) underlie this resistance. Many studies have detailed how alterations in GRα function lead to diminished GC sensitivity; however, the current review highlights the wealth of data concerning reductions in the GRα pool, mediated by disease-associated and treatment-associated effects, which contribute to a significant decrease in GC sensitivity. Additionally, the current understanding of the molecular mechanisms involved in driving reductions in the GRα pool is discussed. After highlighting the importance of maintaining the level of the GRα pool to combat GC resistance, we present current strategies and argue that future strategies to prevent GC resistance should involve biased ligands with a predisposition for reduced GR dimerization, a strategy originally proposed as the SEMOGRAM-SEDIGRAM concept to reduce the side-effect profile of GCs.

The role of tumor suppressor of resveratrol and prednisolone by downregulation of YKL-40 expression in CCRF-CEM cell line

BACKGROUND

Acute lymphoblastic leukemia (ALL) is characterized by excessive accumulation of lymphoblast and progenitors. Leukemia is the most common cancer in children and ALL is the most common subtype. Many studies have shown that the YKL-40 gene is one of the most widely expressed genes in tumors, including leukemia, but not in healthy blood cells. Clinical studies have shown that serum YKL-40 levels have a positive correlation with tumor expansion, in addition to being a prognostic agent independent of a short relapse-free interval, as well as a brief overall survival in patients with various cancers. The previous study shows that YKL-40 is closely related to the degree of pathology or degree of human leukemia pathology and plays an important role in cell proliferation. Hence, the YKL-40 can be an attractive target in designing anticancer therapies.

METHODS

CCRF-CEM cells were treated with resveratrol and prednisolone. For analysis of YKL-40 expression changes under medication, real-time polymerase chain reaction (PCR) and Western blot techniques were used at resonating intervals of 24 and 48 hours.

RESULTS

The effect of 15, 50, and 100 μM resveratrol and 700 μM of prednisolone on CCRF-CEM cells reduced YKL-40. The YKL-40 gene was quantitatively measured using RT-PCR. The Western blot method was used to evaluate changes in the expression of YKL-40 protein.

CONCLUSION

In this study, we first evaluated YKL-40 expression and resveratrol and prednisolone effect on YKL-40 in ALL. This finding supports the idea of targeting YKL-40 as a new drug treatment of ALL and extends the use of resveratrol in antileukemia research.

Novel role for receptor dimerization in post-translational processing and turnover of the GRα

Glucocorticoids (GCs), acting via the glucocorticoid receptor (GRα), remain the mainstay therapeutic choice for the treatment of inflammation. However, chronic GC use, aside from generating undesirable side-effects, results in GRα down-regulation, often coupled to a decrease in GC-responsiveness, which may culminate in acquired GC resistance. The current study presents evidence for a novel role of the dimerization state of the GRα in mediating GC-mediated GRα turnover. Through comparing the effects of dimerization promoting GCs on down-regulation of a transfected human wild type GRα (hGRwt) or a dimerization deficient GRα mutant (hGRdim), we established that a loss of receptor dimerization restricts GRα turnover, which was supported by the use of the dimerization abrogating Compound A (CpdA), in cells containing endogenous GRα. Moreover, we showed that the dimerization state of the GRα influenced the post-translational processing of the receptor, specifically hyper-phosphorylation at Ser404, which influenced the interaction of GRα with the E3 ligase, FBXW7α, thus hampering receptor turnover via the proteasome. Lastly, the restorative effects of CpdA on the GRα pool, in the presence of Dex, were demonstrated in a combinatorial treatment protocol. These results expand our understanding of factors that contribute to GC-resistance and may be exploited clinically.

Pharmacogenomic markers of glucocorticoid response in the initial phase of remission induction therapy in childhood acute lymphoblastic leukemia

Background

Response to glucocorticoid (GC) monotherapy in the initial phase of remission induction treatment in childhood acute lymphoblastic leukemia (ALL) represents important biomarker of prognosis and outcome. We aimed to study variants in several pharmacogenes (NR3C1, GSTs and ABCB1) that could contribute to improvement of GC response through personalization of GC therapy.

Methods

Retrospective study enrolling 122 ALL patients was carried out to analyze variants of NR3C1 (rs33389, rs33388 and rs6198), GSTT1 (null genotype), GSTM1 (null genotype), GSTP1 (rs1695 and rs1138272) and ABCB1 (rs1128503, rs2032582 and rs1045642) genes using PCR-based methodology. The marker of GC response was blast count per microliter of peripheral blood on treatment day 8. We carried out analysis in which cut-off value for GC response was 1000 (according to Berlin-Frankfurt-Munster [BFM] protocol), as well as 100 or 0 blasts per microliter.

Results

Carriers of rare NR3C1 rs6198 GG genotype were more likely to have blast count over 1000, than the non-carriers (p = 0.030). NR3C1 CAA (rs33389-rs33388-rs6198) haplotype was associated with blast number below 1000 (p = 0.030). GSTP1 GC haplotype carriers were more likely to have blast number below 1000 (p = 0.036), below 100 (p = 0.028) and to be blast negative (p = 0.054), while GSTP1 GT haplotype and rs1138272 T allele carriers were more likely to be blasts positive (p = 0.034 and p = 0.024, respectively). ABCB1 CGT (rs1128503-rs2032582-rs1045642) haplotype carriers were more likely to be blast positive (p = 0.018).

Conclusions

Our results have shown that NR3C1 rs6198 variant and GSTP1 rs1695-rs1138272 haplotype are the most promising pharmacogenomic markers of GC response in ALL patients.

HIV/AIDS-related hyponatremia: an old but still serious problem

Hyponatremia is the most common electrolyte disorder in hospitals. Many medical illnesses, including congestive heart failure, liver failure, renal failure and pneumonia, may be associated with hyponatremia. In addition, hyponatremia in patients with the acquired immunodeficiency syndrome (AIDS) and AIDS-related complex (ARC) was first reported in 1993. The evidence suggests that severe hyponatremia is associated with increased morbidity and mortality in human immunodeficiency virus (HIV)/AIDS patients; however, the incidence of hyponatremic syndrome in HIV/AIDS patients remains very high in clinical practice, as almost 40% of HIV/AIDS inpatients in Xinjiang, a developing region of China, are hyponatremic. A method for identifying the pathogenesis and therapeutic treatments for hyponatremia in HIV/AIDS patients is needed. This review focuses on the clinical and pathophysiological aspects of hyponatremia and highlights the causes, presentation and treatment recommendations for hyponatremic patients with HIV/AIDS.

Decreased H3K9ac level of StAR mediated testicular dysplasia induced by prenatal dexamethasone exposure in male offspring rats

Prenatal dexamethasone exposure (PDE) could induce testicular developmental toxicity in adults. The present study aims to confirm its intrauterine origination, and to explore its potential intrauterine programming mechanism. The pregnant rats were respectively injected subcutaneously with 0.2 and 0.8 mg/kg d dexamethasone during gestational days (GD) 9 to 20. The testes and serum of offspring rats were collected on GD20 and postnatal week (PW) 12. In vivo, PDE significantly induced the abnormal testicular morphology in offspring from GD20 to PW12. Moreover, the serum and intratesticular testosterone levels and the expression of testicular steroidogenic acute regulatory protein (StAR) were reduced by PDE. The expression levels of glucocorticoid receptor (GR) and histone deacetylase 7 (HDAC7) were increased in fetal testes. Furthermore, the histone 3 lysine 9 acetylation (H3K9ac) level in the StAR promoter was decreased by PDE from GD20 to PW12. In vitro, mouse Leydig tumour cell line (MLTC-1) cells were treated with dexamethasone (20, 100 and 500 nM), and the testosterone production and StAR expression were reduced. Moreover, dexamethasone increased the expression of HDAC7 by activating GR, which decreased the H3K9ac level in the StAR promoter. Taken together, PDE caused testicular dysplasia before and after birth in male offspring rats, and its mechanism was related to the low-expressional programming of StAR mediated by decreasing H3K9ac level.

Peripheral sensitivity to steroids revisited

Resistance to steroid hormones presents a serious problem with respect to their mass use in therapy. It may be caused genetically by mutation of genes involved in hormonal signaling, not only steroid receptors, but also other players in the signaling cascade as co-regulators and other nuclear factors, mediating the hormone-born signal. Another possibility is acquired resistance which may develop under long-term steroid treatment, of which a particular case is down regulation of the receptors. In the review recent knowledge is summarized on the mechanism of main steroid hormone action, pointing to already proven or potential sites causing steroid resistance. We have attempted to address following questions: 1) What does stay behind differences among patients as to their response to the (anti)steroid treatment? 2) Why do various tissues/cells respond differently to the same steroid hormone though they contain the same receptors? 3) Are such differences genetically dependent? The main attention was devoted to glucocorticoids as the most frequently used steroid therapeutics. Further, androgen insensitivity is discussed with a particular attention to acquired resistance to androgen deprivation therapy of prostate cancer. Finally the potential causes are outlined of breast and related cancer(s) resistance to antiestrogen therapy.

Effect of combining glucocorticoids with Compound A on glucocorticoid receptor responsiveness in lymphoid malignancies

Glucocorticoids (GCs) are a cornerstone in the treatment of lymphoid malignancies such as multiple myeloma (MM) and acute lymphoblastic leukemia (ALL). Yet, prolonged GC use is hampered by deleterious GC-related side effects and the emergence of GC resistance. To tackle and overcome these GC-related problems, the applicability of selective glucocorticoid receptor agonists and modulators was studied, in search of fewer side-effects and at least equal therapeutic efficacy as classic GCs. Compound A (CpdA) is a prototypical example of such a selective glucocorticoid receptor modulator and does not support GR-mediated transactivation. Here, we examined whether the combination of CpdA with the classic GC dexamethasone (Dex) may improve GC responsiveness of MM and ALL cell lines. We find that the combination of Dex and CpdA does not substantially enhance GC-mediated cell killing. In line, several apoptosis hallmarks, such as caspase 3/7 activity, PARP cleavage and the levels of cleaved-caspase 3 remain unchanged upon combining Dex with CpdA. Moreover, we monitor no additional inhibition of cell proliferation and the homologous downregulation of GR is not counteracted by the combination of Dex and CpdA. In addition, CpdA is unable to modulate Dex-liganded GR transactivation and transrepression, yet, Dex-mediated transrepression is also aberrant in these lymphoid cell lines. Together, transrepression-favoring compounds, alone or combined with GCs, do not seem a valid strategy in the treatment of lymphoid malignancies.

Using Radiolabeled 3'-Deoxy-3'-18F-Fluorothymidine with PET to Monitor the Effect of Dexamethasone on Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) is a leading cause of cancer mortality in the United States, and pemetrexed-based therapies are regularly used to treat nonsquamous NSCLC. Despite widespread use, pemetrexed has a modest effect on progression-free survival, with varying efficacy between individuals. Recent work has indicated that dexamethasone, given to prevent pemetrexed toxicity, is able to protect a subset of NSCLC cells from pemetrexed cytotoxicity by temporarily suppressing the S phase of the cell cycle. Therefore, dexamethasone might block treatment efficacy in a subpopulation of patients and might be contributing to the variable response to pemetrexed. Methods: Differences in retention of the experimental PET tracer 3'-deoxy-3'-fluorothymidine (FLT) were used to monitor S-phase suppression by dexamethasone in NSCLC cell models, animals with tumor xenografts, and patients with advanced cancer. Results: Significant reductions in tracer uptake were observed after 24 h of dexamethasone treatment in NSCLC cell lines and xenograft models expressing high levels of glucocorticoid receptor α, coincident with pemetrexed resistance visualized by attenuation of the flare effect associated with pemetrexed activity. Two of 4 patients imaged in a pilot study with ¹⁸F-FLT PET after dexamethasone treatment demonstrated reductions in tracer uptake from baseline, with a variable response between individual tumor lesions. Conclusion: ¹⁸F-FLT PET represents a useful method for the noninvasive monitoring of dexamethasone-mediated S-phase suppression in NSCLC and might provide a way to individualize chemotherapy in patients receiving pemetrexed-based regimens.

Anti-inflammatory effect of 4-methylcyclopentadecanone in rats submitted to ischemic stroke

This study aimed to investigate the anti-inflammatory effect of 4-methylcyclopentadecanone (4-MCPC) in rats suffering from a cerebral ischemia/reperfusion (I/R) injury. In this study, the focal cerebral ischemia in rats was induced by middle cerebral artery occlusion (MCAO) for 2 h, and the rats were treated with 4-MCPC (8 mg/kg) just 0.5 h before reperfusion. The ischemic infarct volume was recorded 24 h after the MCAO. In addition, myeloperoxidase (MPO) activity and TNF-α and IL-1β levels in the ischemic cerebral cortex were determined by ELISA, while nuclear translocation of NF-κB p65 subunit and expression of p-IκBα were investigated by Western blotting. Our results showed that 4-MCPC treatment decreased infarct volume significantly, compared with I/R group (16.8%±7.5% vs. 39.7%±10.9%); it reduced MPO activity (0.43 ± 0.10 vs. 1.00 ± 0.51 U/g) and expression levels of TNF-α (18.90 ± 3.65 vs. 35.87 ± 4.87 ng/g) and IL-1β (1.68 ± 0.23 vs. 2.67 ± 0.38 ng/g) in ischemic brain tissues of rats. Further study revealed that 4-MCPC treatment markedly reduced nuclear translocation of NF-κB p65 subunit and expression of p-IκBα in ischemic cerebral cortex. Taken together, our results suggest that 4-MCPC protects against cerebral I/R injury and displays anti-inflammatory actions through inhibition of the NF-κB signal pathway.

Regulatory effect of resveratrol and prednisolone on MDR1 gene expression in acute lymphoblastic leukemia cell line (CCRF-CEM): An epigenetic perspective

Chemotherapy is the most common method to treat leukemia as well as other types of human cancers. However, drug resistance has remained as the main challenge against the efficacy of treatments. Furthermore, having various adverse effects, chemotherapy drugs are becoming replaced by natural modalities for cancer therapy. In this regard, herbal components such as resveratrol and prednisolone have been identified to sensitize the leukemic cells to programmed cell death through a set of complex processes. In this study, we have examined DNA methylation on the human multidrug resistance gene 1 (MDR1) as a well-known marker for cellular drug resistance. We evaluated the effect of resveratrol and prednisolone on DNA methylation patterns of MDR1 gene promoter in the CCRF-CEM cell line as a representative for acute lymphoblastic leukemia. The study was aimed to clarify whether the MDR1 gene expression is regulated via DNA promoter methylation as a potential underlying mechanism, following exposure to resveratrol and prednisolone. Our data revealed that despite a strong influence to down-regulate the MDR1 expression, Resveratrol and Prednisolone did not alter the methylation pattern, suggesting other regulatory mechanisms in controlling the MDR1 expression in CCRF-CEM cell line. Unchanged status of DNA methylation of MDR1 gene may suggest that Resveratrol and Prednisolone causes the gene expression changes through a distinct mechanism which requires further studies to be understood. A more detailed understanding of the mechanisms beyond the regulation of the genes involved in cancer formation will help to design novel therapeutic strategies to fight the human cancers.

Overcoming tumor cell chemoresistance using nanoparticles: lysosomes are beneficial for (stearoyl) gemcitabine-incorporated solid lipid nanoparticles

Despite recent advances in targeted therapies and immunotherapies, chemotherapy using cytotoxic agents remains an indispensable modality in cancer treatment. Recently, there has been a growing emphasis in using nanomedicine in cancer chemotherapy, and several nanomedicines have already been used clinically to treat cancers. There is evidence that formulating small molecular cancer chemotherapeutic agents into nanomedicines significantly modifies their pharmacokinetics and often improves their efficacy. Importantly, cancer cells often develop resistance to chemotherapy, and formulating anticancer drugs into nanomedicines also helps overcome chemoresistance. In this review, we briefly describe the different classes of cancer chemotherapeutic agents, their mechanisms of action and resistance, and evidence of overcoming the resistance using nanomedicines. We then emphasize on gemcitabine and our experience in discovering the unique (stearoyl) gemcitabine solid lipid nanoparticles that are effective against tumor cells resistant to gemcitabine and elucidate the underlying mechanisms. It seems that lysosomes, which are an obstacle in the delivery of many drugs, are actually beneficial for our (stearoyl) gemcitabine solid lipid nanoparticles to overcome tumor cell resistance to gemcitabine.

Combination of icariin and oleanolic acid attenuates in vivo and in vitro glucocorticoid resistance through protecting dexamethasone-induced glucocorticoid receptor impairment

Glucocorticoid resistance (GCR) remains a significant problem and is the most important reason for treatment failure of glucocorticoids (GCs).

Correlation between polymorphisms of the NR3C1 gene and glucocorticoid effectiveness in patients with pemphigus vulgaris

Glucocorticoid (GC) resistance is the major obscule in the treatment of pemphigus vulgaris (PV) for both patients and clinicans with unclear mechanism. A hypotheis for this resistance is the mutations or polymorphisms present in the nuclear receptor subfamily 3, group C, member 1 (NR3C1) gene that encodes receptors for steroid hormones. This study aimed to investigate the association between NR3C1 gene polymorphisms and GC effectiveness in PV patients. 94 PV patients (64 GC-sensitive and 30 GC-resistant) and 100 healthy volunteers were enrolled in this case-control study. The genotyping of single nucleotide polymorphisms (SNPs) in BCL1, Arg23Lys, Asn363Ser 1548 t-insert, and le747Met, together with tag-SNP sites of the NR3C1 gene were evaluated. No significant differences were observed in genotypic and allelic frequencies of the 16 SNPs between PV patients and healthy volunteers. However, SNPs rs 11745958 C/T (OR: 8.95) and rs17209237 A/G (OR: 4.07) may be associated with an increased risk of GC resistance, while rs 33388 A/T (OR: 0.45) and rs7701443 A/G (OR: 0.51) may indicate a decreased risk of GC resistance in PV patients. NR3C1 gene variation may be associated with GC resistance in PV patients. More extensive genetic analyses and mechanistic analysis are required for further exploration.

Effect of a corticosteroid (triamcinolone) and chlorhexidine on chemotherapy-induced oxidative stress in the buccal mucosa of rats

Oral mucositis manifests as erythematous and ulcerative lesions of the oral mucosa. Among its various causes, cancer treatment (e.g., chemotherapy with or without radiation therapy) is one of the more well known. It has been widely mentioned that oxidative stress parameters such as lipid peroxidation levels increase during the cancer process. Glutathione is one of the major intracellular enzymes used to detoxify oxidant molecules; it exists in both a reduced and oxidized state. Reduced glutathione is used as a substrate to synthesize glutathione peroxidase. We conducted a study to investigate and compare the effects of triamcinolone (a synthetic steroid) and chlorhexidine (a chemical antiseptic) on 5-fluorouracil (5-FU; a chemotherapeutic agent)-induced oral mucositis in the buccal mucosa of 36 rats. Oral mucositis was induced through a combination of 5-FU treatment and mild abrasion of the cheek pouch with a wire brush. The rats were treated with one of four regimens: saline placebo (group I), 5-FU only (group II), 5-FU plus triamcinolone (group III), and 5-FU plus chlorhexidine (group IV). Three rats in the triamcinolone group died of unknown causes on days 7 and 8, and 3 rats in the chlorhexidine group died on days 7 and 9. On day 9, the remaining 30 rats were sacrificed and examined. Buccal mucosa lipid peroxidation levels were significantly higher in the 5-FU-only group than in the control group and significantly higher in the control group than in the triamcinolone group (p < 0.05 for both). Levels of reduced glutathione were significantly lower in the 5-FU-only group than in both the triamcinolone group and the chlorhexidine group (p < 0.05). Glutathione peroxidase activity was significantly higher in the triamcinolone group than in the 5-FU-only group (p < 0.01). Histopathologic analysis revealed that treatment with triamcinolone significantly reduced 5-FU-induced inflammatory cell infiltration and ulceration (p < 0.001); no such reduction was seen with chlorhexidine. In conclusion, we observed that triamcinolone and chlorhexidine treatment modulated chemotherapy-induced oxidative injury in rat oral mucositis. However, only triamcinolone histopathologically ameliorated 5-FU-induced oral mucositis. These findings suggest that triamcinolone is a useful agent for the management of experimental oxidative injury and oral mucositis caused by 5-FU chemotherapy.

Hydrocortisone-induced parkin prevents dopaminergic cell death via CREB pathway in Parkinson's disease model

Dysfunctional parkin due to mutations or post-translational modifications contributes to dopaminergic neurodegeneration in Parkinson's disease (PD). Overexpression of parkin provides protection against cellular stresses and prevents dopamine cell loss in several PD animal models. Here we performed an unbiased high-throughput luciferase screening to identify chemicals that can increase parkin expression. Among promising parkin inducers, hydrocortisone possessed the most favorable profiles including parkin induction ability, cell protection ability, and physicochemical property of absorption, distribution, metabolism, and excretion (ADME) without inducing endoplasmic reticulum stress. We found that hydrocortisone-induced parkin expression was accountable for cell protection against oxidative stress. Hydrocortisone-activated parkin expression was mediated by CREB pathway since gRNA to CREB abolished hydrocortisone's ability to induce parkin. Finally, hydrocortisone treatment in mice increased brain parkin levels and prevented 6-hydroxy dopamine induced dopamine cell loss when assessed at 4 days after the toxin's injection. Our results showed that hydrocortisone could stimulate parkin expression via CREB pathway and the induced parkin expression was accountable for its neuroprotective effect. Since glucocorticoid is a physiological hormone, maintaining optimal levels of glucocorticoid might be a potential therapeutic or preventive strategy for Parkinson's disease.

Integrated transcriptome and methylome analysis in youth at high risk for bipolar disorder: a preliminary analysis

First-degree relatives of patients with bipolar disorder (BD), particularly their offspring, have a higher risk of developing BD and other mental illnesses than the general population. However, the biological mechanisms underlying this increased risk are still unknown, particularly because most of the studies so far have been conducted in chronically ill adults and not in unaffected youth at high risk. In this preliminary study we analyzed genome-wide expression and methylation levels in peripheral blood mononuclear cells from children and adolescents from three matched groups: BD patients, unaffected offspring of bipolar parents (high risk) and controls (low risk). By integrating gene expression and DNA methylation and comparing the lists of differentially expressed genes and differentially methylated probes between groups, we were able to identify 43 risk genes that discriminate patients and high-risk youth from controls. Pathway analysis showed an enrichment of the glucocorticoid receptor (GR) pathway with the genes MED1, HSPA1L, GTF2A1 and TAF15, which might underlie the previously reported role of stress response in the risk for BD in vulnerable populations. Cell-based assays indicate a GR hyporesponsiveness in cells from adult BD patients compared to controls and suggest that these GR-related genes can be modulated by DNA methylation, which poses the theoretical possibility of manipulating their expression as a means to counteract the familial risk presented by those subjects. Although preliminary, our results suggest the utility of peripheral measures in the identification of biomarkers of risk in high-risk populations and further emphasize the potential role of stress and DNA methylation in the risk for BD in youth.