Reduced Glucocorticoid Sensitivity Research Articles

Glucocorticoid Sensitivity Among Young Survivors of Childhood Acute Lymphoblastic Leukemia: What Does It Matter?

The aim of the study was to assess glucocorticoid sensitivity in survivors of childhood acute lymphoblastic leukemia using in vivo and in vitro tests. Thirty leukemia survivors of both sexes aged ≥18 years participated in the study and at least two years after therapy withdrawal. In vivo tests comprised: a) a very low dose intravenous dexamethasone suppression test for measurement of serum cortisol before, after, and % suppression, compared with 32 age-matched controls; and b) 0.25 mg overnight oral dexamethasone suppression test for assessment of salivary cortisol before, after, and % suppression. In vitro methods comprised: c) glucocorticoid receptor polymorphisms: BcI1-NR3C1 and A3669G; and d) splicing variant of glucocorticoid receptor GR-α mRNA by real-time quantitative polymerase chain reaction, compared with 32 controls. There was a reduction in salivary cortisol, and 73.3% of leukemia survivors showed high sensitivity according to % suppression after oral dexamethasone (p<0.05). Serum cortisol at baseline, after the test, % suppression after intravenous dexamethasone, and the percentage of high sensitivity were reduced in the leukemia group (%F=36.7; p<0.05). The BcI1-NR3C1 and A3669G polymorphisms were present in 11/30 (36.7%) and 5/30 (16.7%) patients, respectively. GR-α mRNA levels were lower in the leukemia group than in the controls (p<0.05). Survivors of acute lymphoblastic leukemia presented with reduced glucocorticoid sensitivity. Glucocorticoid sensitivity allows individualized treatment to avoid adverse effects and may be involved in cardiovascular disease risk among this particular group of cancer survivors.

Neighborhood Social Conditions, Family Relationships, and Childhood Asthma

E Chen, R Hayen, V Le. Pediatrics . 2019;144(2):e20183300 To determine if positive family relationships mitigate the negative impact that residing in a dangerous neighborhood can have on asthma. In total, 308 children (age 9–17 years) with physician-diagnosed asthma living in the Chicago area were studied. The majority (70%) had mild-moderate persistent asthma, and 14% had severe asthma. Exclusion criteria included other chronic diseases and acute respiratory illness. This was a cross-sectional, observational study. Neighborhood danger was assessed by two raters who observed subjects’ neighborhoods on Google Earth Pro and Google Street View Imagery. Signs of physical disorder (litter, graffiti, …

Neighborhood Social Conditions, Family Relationships, and Childhood Asthma.

Poor neighborhood conditions have established associations with poorer child health, but little is known about protective factors that mitigate the effects of difficult neighborhood conditions. In this study, we tested if positive family relationships can buffer youth who live in dangerous and/or disorderly neighborhoods from poor asthma outcomes. A total of 308 youths (aged 9-17) who were physician-diagnosed with asthma and referred from community pediatricians and/or family practitioners participated in this cross-sectional study. Neighborhood conditions around families' home addresses were coded by using Google Street View images. Family relationship quality was determined via youth interviews. Clinical asthma outcomes (asthma symptoms, activity limitations, and forced expiratory volume in 1 second percentile), asthma management behaviors (family response to asthma symptoms and integration of asthma into daily life), and asthma-relevant immunologic processes (lymphocyte T helper 1 and T helper 2 cytokine production and sensitivity to glucocorticoid inhibition) were assessed via questionnaires, interviews, spirometry, and blood draws. Significant interactions were found between neighborhood conditions and family relationship quality (β = |.11-.15|; P < .05). When neighborhood danger and/or disorder was low, family relationships were not associated with asthma. When neighborhood danger and/or disorder was high, better family relationship quality was associated with fewer asthma symptoms, fewer activity limitations, and higher forced expiratory volume in 1 second percentile. Similar patterns emerged for asthma management behaviors. With immunologic measures, greater neighborhood danger and/or disorder was associated with greater T helper 1 and T helper 2 cytokine production and reduced glucocorticoid sensitivity. When youth live in dangerous and/or disorderly neighborhoods, high family relationship quality can buffer youth from poor asthma outcomes. Although families may not be able to change their neighborhoods, they may nonetheless be able to facilitate better asthma outcomes in their children through strong family relationships.

SAT-204 Silencing of Maternal Hepatic Glucocorticoid Receptor Is Essential for Normal Fetal Development

Excessive or chronic stress can lead to a variety of diseases due to aberrant activation of the glucocorticoid receptor (GR), a ligand activated transcription factor. Pregnancy represents a particular window of sensitivity in which excessive stress can have adverse outcomes, particularly on the developing fetus. Models of maternal stress have historically relied on the use of psychosocial stressors or chronic administration of glucocorticoids leading to systemic increases in glucocorticoids, making it near impossible to understand the tissue-specific effects of stress during pregnancy in contributing to maternal and fetal diseases. We have previously demonstrated an antagonistic relationship between reproductive axis activity and hepatic glucocorticoid sensitivity in a mouse model of menopause. However, if stress/sex hormone crosstalk exists in the liver during pregnancy, and if so, what the physiological purpose it serves is completely unknown. We have discovered hepatic stress hormone responsiveness is diminished during pregnancy. Utilizing whole transcriptome array we profiled the maternal hepatic transcriptome and found a substantial overlap between the pregnancy-regulated transcriptome and glucocorticoid regulated transcriptome. Of the overlapping genes and pathways, we observed the direction of regulation to be largely opposite between the pregnancy-regulated transcriptome and stress hormone regulated transcriptome. Furthermore, we observed reduced basal expression of classical GR target genes in the pregnant liver and impaired induction of GR target genes in response to dexamethasone treatment in the liver of pregnant versus virgin mice. The reduced glucocorticoid sensitivity in the liver during pregnancy is due to impaired expression of GR, which is mediated via epigenetic silencing. Provocatively, we found reinstallation of GR to hepatocytes during pregnancy via adeno-associated viral transduction dysregulates genes involved in proliferation, ultimately culminating in impaired pregnancy-induced hepatomegaly. Furthermore. disruption of the maternal hepatic adaptation to pregnancy by GR reinstallation results in impaired in utero growth of the fetus. These data demonstrate the tissue-specific effects of stress hormone signaling in the maternal compartment is regulated in a dynamic fashion to ultimately support the healthy development of embryos.

Glucocorticoid sensitivity and inflammatory status of peripheral blood mononuclear cells in patients with coronary artery disease

Objective: Mechanisms behind sustained inflammation in patients with coronary artery disease (CAD) are not clarified but hypothalamus-pituitary-adrenal (HPA) axis dysfunction may have a role. Here, we investigated whether inflammatory status of peripheral blood mononuclear cells (PBMCs) was associated with altered glucocorticoid sensitivity in CAD patients.Methods: In 55 CAD patients and 30 controls, mRNA levels of GR-α, GR-β, NF-κB, IκBα, MMP-9 and TIMP-1 were measured in PBMCs. Suppressive effects of dexamethasone on GR-α, GR-β, NF-κB, IκBα, MMP-9 and TIMP-1 mRNA levels were assessed in PBMCs ex vivo. Salivary cortisol was repeatedly measured over 3 days.Results: GR-α mRNA levels were higher in CAD patients than in controls, 0.50 (0.38–0.59) versus 0.26 (0.18–0.37), p < .001, while GR-β mRNA levels were equally low in both groups. GR-α mRNA expression was associated with inflammatory gene expression and, also, with flatter diurnal cortisol rhythm. In both patients and controls, dexamethasone suppressed gene expression of NF-κB, IκBα, MMP-9 and TIMP-1 (p < .001). Dexamethasone also reduced GR-α mRNA levels (p < .001), while LPS increased it (p < .001).Conclusions: PBMCs from CAD patients displayed an inflammatory gene expression profile. This was not explained by reduced glucocorticoid sensitivity. Instead, inflammation was associated with increased expression of GR-α mRNA, suggesting a hypocortisolemic state.Key messages • Peripheral blood mononuclear cells from patients with coronary artery disease (CAD) display an inflammatory gene expression profile. • This inflammatory state cannot be explained by reduced glucocorticoid sensitivity in CAD patients. • Instead, the inflammatory gene expression profile is associated with upregulated levels of glucocorticoid receptor-α mRNA, suggesting a hypocortisolemic state.

Smokers Display Reduced Glucocorticoid Sensitivity Prior to Symptomatic Chronic Disease Development.

Chronic stress plays a critical role in many of today's diseases and causes of death. Tobacco use reliably increases the likelihood of chronic disease development and premature death. In addition, habitual tobacco use elevates risk of chronic inflammatory diseases, and glucocorticoid therapy is often less effective in smokers compared with nonsmokers. Taken together, smokers may develop glucocorticoid insensitivity, thereby removing the body's greatest anti-inflammatory mechanism. The purpose of this study was to examine glucocorticoid sensitivity among 24 smokers and 24 age-, sex-, and body mass index-matched never smokers who were clinically healthy individuals (i.e., no diagnosis or medication use for chronic diseases and normotensive). Participants visited the lab after a 12 hr fast, provided a blood sample, and completed a series of psychosocial questionnaires. Smokers continued smoking ad libitum before the lab visit. Group differences in glucocorticoid sensitivity were examined using ANCOVA and repeated with linear mixed model to account for possible dependence among immune outcomes that matching participants on age, sex, and body mass index may have introduced. Prior to clinical disease onset, smokers' peripheral blood mononuclear cells (PBMCs) exhibited reduced glucocorticoid sensitivity as well as a diminished inflammatory response to lipopolysaccharide compared with never smokers' PBMCs; results were identical regardless of statistical modeling used. Cigarette smoking, a self-initiated pharmacological chronic stressor, may provide a unique opportunity to examine early wear and tear on physiological functioning that may lead to chronic disease development. Additional research into PBMCs' intracellular changes must be examined as well as repeating this study in a larger, more heterogeneous population.

Glucocorticoid Sensitivity Is Highly Variable in Critically Ill Patients With Septic Shock and Is Associated With Disease Severity.

To measure tissue glucocorticoid sensitivity in patients with septic shock and determine its relationship to standard measurements of adrenal function and of outcome. Prospective observational trial. Teaching hospital ICU. Forty-one patients and 20 controls were studied. Glucocorticoid sensitivity was measured by in vitro suppression of cytokine production from lipopolysaccharide-stimulated leukocytes. There was no significant difference between the groups in the relative suppression of cytokine production, although there was a greater range and variance in the patient data. Patients in the lowest quartile of glucocorticoid sensitivity had higher Acute Physiology and Chronic Health Evaluation II scores (25 [24-28] vs 20 [14-23]; p = 0.02) and a trend toward higher mortality (30% vs 0%; p = 0.2) compared to those in the highest. The mRNA expression of the β variant of the glucocorticoid receptor and the 11-β hydroxysteroid dehydrogenase 2 isozyme were significantly higher in patients compared to controls (8.6-fold, p = 0.002 and 10.1-fold, p = 0.0002, respectively). Changes in mRNA expression of these genes did not correlate with measurements of glucocorticoid sensitivity. Patients with septic shock and controls do not differ in their median glucocorticoid sensitivity. However, patients exhibited a greater variability in glucocorticoid responsiveness and had evidence of association between increased sickness sensitivity and reduced glucocorticoid sensitivity. Sensitivity to glucocorticoids did not appear to be mediated by changes in the expression of the β variant of the glucocorticoid receptor or the 11-β hydroxysteroid dehydrogenase 2 isozyme.

Repeated exposure to sleep restriction followed by recovery sleep – Effects on IL-6 expression and glucocorticoid (GC) sensitivity of monocytes

Restricting sleep on week days and catching up on sleep on weekend days is a highly prevalent pattern in work and school populations. We hypothesized that the repeated exposure to such patterns progressively increases the inflammatory response, due to reduced GC sensitivity of monocytes. Fourteen participants (age 25 ± 1 yrs) completed two 25-day-in-hospital periods; sleep-restriction and control-sleep in randomized order. The sleep-restriction condition consisted of three weekly cycles of 5 days with 4 h of sleep/night followed by 2 days with 8 h of sleep/night. Blood draws were taken at 11:30 h on the baseline day and the end of each sleep-restriction and recovery-sleep period. The inflammatory response was assessed by interleukin (IL)-6 positive monocytes (determined by flow cytometry); GC sensitivity of monocytes was determined by measuring the ability of dexamethasone to suppress lipopolysaccharide-stimulated IL-6 expression. IL-6 positive monocytes increased in the second and third week of sleep-restriction over control-sleep by 15% and 20%, respectively (both p 0.05), and did not return to baseline levels during intermittent recovery-sleep. GC sensitivity of monocytes was increased across all 3 weeks of sleep-restriction when compared to control-sleep, and did not normalize during intermittent recovery-sleep periods (all p 0.05). In conclusion, despite an increase in the sensitivity of monocytes to the counter-inflammatory GC signal, monocytes still express more IL-6 in response to repeated exposure of sleep-restriction. Importantly, recovery-sleep does not normalize these changes.

Obesity impairs apoptotic cell clearance in asthma

Asthma in obese adults is typically more severe and less responsive to glucocorticoids than asthma in nonobese adults. We sought to determine whether the clearance of apoptotic inflammatory cells (efferocytosis) by airway macrophages was associated with altered inflammation and reduced glucocorticoid sensitivity in obese asthmatic patients. We investigated the relationship of efferocytosis by airway (induced sputum) macrophages and blood monocytes to markers of monocyte programming, in vitro glucocorticoid response, and systemic oxidative stress in a cohort of adults with persistent asthma. Efferocytosis by airway macrophages was assessed in obese (n=14) and nonobese (n=19) asthmatic patients. Efferocytosis by macrophages was 40% lower in obese than nonobese subjects, with a mean efferocytic index of 1.77 (SD, 1.07) versus 3.00 (SD, 1.25; P<.01). A similar reduction of efferocytic function was observed in blood monocytes of obese participants. In these monocytes there was also a relative decrease in expression of markers of alternative (M2) programming associated with efferocytosis, including peroxisome proliferator-activated receptor δ and CX3 chemokine receptor 1. Macrophage efferocytic index was significantly correlated with dexamethasone-induced mitogen-activated protein kinase phosphatase 1 expression (ρ=0.46, P<.02) and baseline glucocorticoid receptor α expression (ρ=0.44, P<.02) in PBMCs. Plasma 4-hydroxynonenal levels were increased in obese asthmatic patients at 0.33 ng/mL (SD, 0.15 ng/mL) versus 0.16 ng/mL (SD, 0.08 ng/mL) in nonobese patients (P=.006) and was inversely correlated with macrophage efferocytic index (ρ=-0.67, P=.02). Asthma in obese adults is associated with impaired macrophage/monocyte efferocytosis. Impairment of this anti-inflammatory process is associated with altered monocyte/macrophage programming, reduced glucocorticoid responsiveness, and systemic oxidative stress.

Evidence for an association between an enhanced reactivity of interleukin-6 levels and reduced glucocorticoid sensitivity in patients with fibromyalgia

Pain and fatigue have been identified as core symptoms of fibromyalgia syndrome (FMS). Since both symptoms are also characteristic of hypocortisolemic disorders, reduced cortisol levels have been thought to promote an exacerbation of these FMS core symptoms by an enhanced reactivity of interleukin-6 (IL-6) levels. The aim of the current study was to investigate the pathophysiologic relevance of reduced cortisol levels for manifestation of FMS core symptoms. Twelve female FMS patients with 15 female controls were compared regarding the function of hypothalamus-pituitary-adrenal (HPA) axis and behavioral, endocrine and IL-6 responses after measuring the pressure pain thresholds (PPTs) at tender points. Function of HPA axis was assessed by determining the cortisol awakening response, daytime profile of cortisol secretion, low dose overnight dexamethasone suppression test (DST) and glucocorticoid sensitivity (GC) of inflammatory cytokine production. While endocrine and IL-6 responses were determined by collecting blood and saliva samples behavioral responses were assessed by pain and fatigue recordings of participants before and after PPT measurement using visual analogue scale (VAS). Whereas FMS patients were found not to differ from controls in cortisol awakening response, daytime profile of cortisol secretion and cortisol suppression after overnight DST, they did exhibit a reduced GC sensitivity of inflammatory cytokine production. PPT measurement did induce three times higher cortisol and four times higher IL-6 levels in FMS patients, but no change in their ACTH levels. The enhanced IL-6 reactivity after PPT measurement was accompanied by an increase in the severity of FMS patients' pain and fatigue ratings. The findings of the present study provide evidence for the pathophysiologic relevance of a disturbed glucocorticoid receptor (GR) function, rather than reduced cortisol levels for the maintenance of FMS core symptoms.

Biological and Diurnal Variation in Glucocorticoid Sensitivity Detected with a Sensitivein VitroDexamethasone Suppression of Cytokine Production Assay

Glucocorticoid resistance due to mutations of the glucocorticoid receptor (NR3C1) are rare, but reduced glucocorticoid sensitivity may play a role in steroid-resistant asthma, inflammatory bowel disease, and septic shock. A rapid and sensitive functional assay to detect glucocorticoid resistance will be advantageous. We describe a rapid in vitro monocyte dexamethasone suppression of cytokine production (DSCP) assay with a 3-h incubation. The DSCP assay was compared with the reference stimulated lymphocyte proliferation method. We characterized the effect of delayed processing, time of sampling, and biological variation on the DSCP assay. The DSCP assay clearly distinguished subjects with a known heterozygous mutation of the NR3C1 gene from control subjects, whereas the reference method failed. Decreased glucocorticoid sensitivity was demonstrated in samples collected in the afternoon. Intra-individual variation from samples collected in the morning was 13.0 and 12.7% for the IL-6 and TNF-alpha responses with the respective inter-individual variations of 9.7 and 7.9%. The DSCP assay was superior to the reference method and was sufficiently sensitive to detect diurnal variation in control subjects. The biological variation data supported the use of a population-based reference interval. The assay is suitable for screening of glucocorticoid resistance phenotypes and may provide insight into cortisol metabolism in critically ill patients, asthmatics, and patients with inflammatory bowel disease provided that the variation due to delayed processing and time of collection are considered.

Overcoming Reduced Glucocorticoid Sensitivity in Airway Disease

There is a considerable and growing unmet medical need in respiratory disease concerning effective anti-inflammatory therapies for conditions such as severe asthma, chronic obstructive pulmonary disease and cystic fibrosis. These diseases share a predominant characteristic of an enhanced and uncontrolled inflammatory response in the lungs, which contributes to disease progression, hospitalization and mortality. These diseases are poorly controlled by current anti-inflammatory therapies including glucocorticoids, which are otherwise effective in many other inflammatory conditions or in milder disease such as asthma. The exact cause of this apparent impairment of glucocorticoid function remains largely unclear; however, recent studies have now implicated a number of possible mechanisms. Central among these is an elevation of the oxidant burden in the lungs and the resulting reduction in the activity of histone deacetylase (HDAC)-2. This contributes to both the enhancement of proinflammatory mediator expression and the impaired ability of the glucocorticoid receptor (GR)-alpha to repress proinflammatory gene expression. The oxidant-mediated reduction in HDAC-2 activity is, in part, a result of an elevation in the phosphoinositol 3-kinase (PI3K) delta/Akt signalling pathway. Blockade of the PI3Kdelta pathway restores glucocortiocoid function in both in vitro and in vivo models, and in primary cells from disease. In addition, inhibition of the PI3Kdelta and PI3Kgamma isoforms is anti-inflammatory in both innate and adaptive immune responses. Consequently, selective inhibition of this pathway may provide a therapeutic strategy both as a novel anti-inflammatory and in combination therapy with glucocorticoids to restore their function. However, a number of other oxidant-related and -unrelated mechanisms, including altered kinase signalling and expression of the dominant negative GRbeta, may also play a role in the development of glucocorticoid insensitivity. Further elucidation of these mechanisms and pathways will enable novel therapeutic targeting for alternative anti-inflammatory drugs or combination therapies providing restoration for the anti-inflammatory action of glucocorticoids.

Glucocorticoid receptor gene and depression in patients with coronary heart disease: The Heart and Soul Study—2009 Curt Richter Award Winner

Alterations of glucocorticoid receptor sensitivity have been associated with depression. Thus, variation in the glucocorticoid receptor gene that determines glucocorticoid sensitivity may influence risk for depression. In a cross-sectional genetic association study of 526 white outpatients with chronic coronary heart disease, we examined whether haplotypes of the glucocorticoid receptor gene (NR3C1) are associated with depression. Participants were genotyped for four common glucocorticoid receptor gene polymorphisms (ER22/23EK, BclI C/G, N363S, and 9beta A/G) and haplotype analyses were conducted. Depression was assessed by an interview (Computerized Diagnostic Interview Schedule). Of the 526 participants, 355 (67.5%) were non-carriers, 153 (29.1%) had one copy, and 17 (3.2%) had 2 copies of the haplotype 3 allele, which includes the minor allele of the 9beta A/G polymorphism and which has been associated with reduced glucocorticoid sensitivity. The prevalence of depression ranged from 24.4% in the non-carriers to 34.4% in heterozygotes to 52.9% in participants homozygous for the haplotype 3 allele (p<0.01). In logistic regression analyses, carriers of one haplotype 3 allele had an odds ratio of 1.64 (95% CI 1.1-2.5, p=0.02) for depression, while the odds ratio of homozygous haplotype 3 carriers was 3.52 (95% CI 1.3-9.4, p=0.01). These associations persisted after adjusting for potentially confounding variables. A common GR haplotype was associated with depression in a gene-dosage dependent manner and might be a vulnerability factor for depression.

Stress and memory retrieval in women: No strong impairing effect during the luteal phase.

Stress has been shown to impair delayed memory retrieval, but so far no study has been conducted solely with naturally cycling women. In a crossover design, 36 women (all in the luteal phase) participated in two experimental conditions (stress vs. control). Delayed memory retrieval of a wordlist learned 24 hours earlier was tested after stress or control treatment. Although stressed subjects showed a strong cortisol increase following stress, no influence on memory retrieval occurred. In an additional data analysis, subjects were split up into a cortisol responder and a cortisol nonresponder group. However, again no evidence for a stress-induced retrieval impairment became apparent. Similarly, no correlation was observed between the stress-induced cortisol increase and memory. This study failed to find an influence of stress on memory retrieval in women tested in the luteal phase. The findings are in contrast to our previous results obtained with men. Evidence is discussed that the luteal phase, which is characterized by elevated gonadal steroids, is associated with reduced glucocorticoid sensitivity. This might underlie the missing impact of stress on memory.

Increased Expression of the Glucocorticoid Receptor-A Translational Isoform as a Result of the ER22/23EK Polymorphism

One of the most intriguing polymorphisms in the GR [glucocorticoid (GC) receptor] gene is in codons 22 and 23 [GAGAGG(GluArg) --> GAAAAG (GluLys)]. This polymorphism is associated with a reduced GC sensitivity, a better metabolic and cardiovascular health profile, and an increased survival rate. Recently, Yudt and Cidlowski reported that two different methionine codons in the GR mRNA may be used as initiation codon: AUG-1 and AUG-27, resulting in two isoforms, the GR-A and the GR-B proteins, respectively. They also showed that the GR-B protein had a stronger transactivating effect in transient transfection experiments. In this study, we elucidated the molecular basis for the reduced GC sensitivity by investigating the influence of the ER22/23EK polymorphism on synthesis of GR-A and GR-B by expressing them independently from constructs with and without the polymorphic site. Binding studies with [(3)H]-dexamethasone and transactivation studies showed that, when the ER22/23EK polymorphism is present, approximately 15% more GR-A protein was expressed, whereas total GR levels (GR-A + GR-B) were not affected. These results show that the transcriptional activity in GR(ER22/23EK) carriers is decreased because more of the less transcriptionally active GR-A isoform is formed. This is probably caused by altered secondary mRNA structure.

Reduced glucocorticoid sensitivity of monocyte interleukin-6 release in male employees with high plasma levels of tumor necrosis factor-α

Cytokine production by monocytes plays a key role in atherosclerosis. In vitro, preincubation of whole blood with tumor necrosis factor (TNF)-α regulates interleukin (IL)-6 release from monocytes stimulated with lipopolysaccharide (LPS). We investigated whether plasma levels of TNF-α would also relate to LPS-stimulated monocyte IL-6 production and the inhibitory effect of a glucocorticoid on this process. 224 middle-aged men were assigned to three groups according to tertiles of plasma levels of TNF-α. Subjects in the highest tertile (high TNF-α, n = 75) were compared to those in the lowest (low TNF-α, n = 74) and medium tertile (medium TNF-α, n = 75), respectively. In vitro monocyte IL-6 release following lipopolysaccharide (LPS)-stimulation was assessed with and without coincubation with incremental doses of dexamethasone. Monocyte glucocorticoid sensitivity was defined as the dexamethasone concentration inhibiting IL-6 release by 50%. Subjects with high TNF-α showed more IL-6 release after LPS-stimulation than those with low TNF-α (p = .011). Monocyte glucocorticoid sensitivity was lower in subjects with high levels of TNF-α than in subjects with low (p = .014) and with medium (p = .044) levels of TNF-α. Results held significance when a set of classic cardiovascular risk factors was controlled for. Our findings suggest that elevated plasma levels of TNF-α might enhance LPS-stimulated IL-6 release from circulating monocytes. Such a mechanism might contribute to exaggerated monocyte cytokine release in vivo to any LPS-like danger signal such as related to an infection or cellular stress thereby promoting atherosclerosis.

Low glucocorticoid receptor alpha/beta ratio in T-cell lymphoblastic leukemia.

Glucocorticoid therapy is pivotal in the treatment of acute lymphoblastic leukemia (ALL); it reduces cell proliferation, promotes cell cycle arrest, and induces cell death by apoptosis. The sensitivity of leukemic cells to glucocorticoids was previously related to the cell concentration of 3[H]dexamethasone-binding sites. The latter represents the classic glucocorticoid receptor (GR) isoform alpha that binds ligand and modulates the transcription rates of glucocorticoid-responsive genes. In ALL, lymphoblasts of T-lineage are less sensitive to glucocorticoids than cells of the B-lineage. The alternatively spliced GR isoform (GRP), which exerts a dominant negative effect on GRalpha-mediated transcriptional activity, has been proposed as a possible mediator of glucocorticoid resistance. In this study, we determined the amount of GRalpha and GRbeta in mononuclear cells from 13 newly diagnosed and untreated children with ALL and 9 controls by quantitative Western analysis. Generally, leukemic patients expressed 6 times less GRalpha (ALL= 0.54 +/- 1.1; controls = 3.1 +/- 0.9; p < 0.01) than controls, but the same amount of GRbeta (ALL=3.62 +/- 3.3; controls = 3.6 +/- 3.4). ALL patients with T-cell disease had a much lower GRalpha (0.09 +/- 0.1; p < 0.01) but a similar or slightly higher GRbeta (5.98 +/- 3.9; p = 0.1) expression than controls, with a GRalpha/GRbeta ratio 15 times smaller than controls. Mononuclear leukocytes of T-cell lineage expressed significantly lower GRalpha (p = 0.04) and higher GRbeta (p < 0.01) than cells of the pre-B immunophenotype, with a 10 times smaller ratio. We conclude that the combination of low GRalpha and normal-to-high GRbeta expression in leukemic lymphoblasts might represent one of the mechanisms responsible for their reduced glucocorticoid sensitivity; this is more pronounced in T-lineage cells.

Activation of alpha-fetoprotein synthesis in rat hepatoma cells with reduced sensitivity to dexamethasone

The Faza 967 ‘differentiated', dexamethasone (DEX)-sensitive cell line of Reuber rat hepatoma cells does not synthesize detectable amounts of alpha-fetoprotein (AFP), whereas it does produce albumin. AFP production was activated in ‘differentiated’ variants of Faza 967 cells with reduced glucocorticoid sensitivity upon culture for several months in the presence of high concentrations of dexamethasone. The stability of AFP production differed among the variants, while albumin synthesis did not change, thus indicating that the regulation of these two genes is not co-ordinated. Using molecular hybridization techniques, we found that the AFP message could not be detected in the non-AFP-producing cells, suggesting that the lack of AFP synthesis most probably originates from a tran-scriptional block of the AFP gene. AFP-producing and non-AFP-producing variants of Faza 967 cells constitute a valuable model system for studying the regulatory mechanisms involved in the activation and inactivation of the gene coding for the oncodevelopmental protein, AFP.