RESUMEN
Introduction: Unlike white adipose tissue depots, bone marrow adipose tissue (BMAT) expands during caloric restriction (CR). Although mechanisms for BMAT expansion remain unclear, prior research suggested an intermediary role for increased circulating glucocorticoids. Methods: In this study, we utilized a recently described mouse model (BMAd-Cre) to exclusively target bone marrow adipocytes (BMAds) for elimination of the glucocorticoid receptor (GR) (i.e. Nr3c1) whilst maintaining GR expression in other adipose depots. Results: Mice lacking GR in BMAds (BMAd-Nr3c1 -/-) and control mice (BMAd-Nr3c1 +/+) were fed ad libitum or placed on a 30% CR diet for six weeks. On a normal chow diet, tibiae of female BMAd-Nr3c1-/- mice had slightly elevated proximal trabecular metaphyseal bone volume fraction and thickness. Both control and BMAd-Nr3c1-/- mice had increased circulating glucocorticoids and elevated numbers of BMAds in the proximal tibia following CR. However, no significant differences in trabecular and cortical bone were observed, and quantification with osmium tetroxide and µCT revealed no difference in BMAT accumulation between control or BMAd-Nr3c1 -/- mice. Differences in BMAd size were not observed between BMAd-Nr3c1-/- and control mice. Interestingly, BMAd-Nr3c1-/- mice had decreased circulating white blood cell counts 4 h into the light cycle. Discussion: In conclusion, our data suggest that eliminating GR from BMAd has minor effects on bone and hematopoiesis, and does not impair BMAT accumulation during CR.
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Adipocitos , Adiposidad , Médula Ósea , Restricción Calórica , Hematopoyesis , Receptores de Glucocorticoides , Animales , Receptores de Glucocorticoides/metabolismo , Receptores de Glucocorticoides/genética , Receptores de Glucocorticoides/deficiencia , Ratones , Adipocitos/metabolismo , Adiposidad/fisiología , Femenino , Médula Ósea/metabolismo , Ratones Noqueados , Huesos/metabolismo , Ratones Endogámicos C57BL , Tejido Adiposo/metabolismo , Masculino , Errores Innatos del MetabolismoRESUMEN
OBJECTIVE: Glucocorticoid resistance is a rare endocrine disease caused by variants of the NR3C1 gene encoding the glucocorticoid receptor (GR). We identified a novel heterozygous variant (GRR569Q) in a patient with uncommon reversible glucocorticoid resistance syndrome. METHODS: We performed ex vivo functional characterization of the variant in patient fibroblasts and in vitro through transient transfection in undifferentiated HEK 293T cells to assess transcriptional activity, affinity, and nuclear translocation. We studied the impact of the variant on the tertiary structure of the ligand-binding domain through 3D modeling. RESULTS: The patient presented initially with an adrenal adenoma with mild autonomous cortisol secretion and undetectable adrenocorticotropin hormone (ACTH) levels. Six months after surgery, biological investigations showed elevated cortisol and ACTH (urinary free cortisol 114â µg/24â h, ACTH 10.9â pmol/L) without clinical symptoms, evoking glucocorticoid resistance syndrome. Functional characterization of the GRR569Q showed decreased expression of target genes (in response to 100â nM cortisol: SGK1 control +97% vs patient +20%, P < .0001) and impaired nuclear translocation in patient fibroblasts compared to control. Similar observations were made in transiently transfected cells, but higher cortisol concentrations overcame glucocorticoid resistance. GRR569Q showed lower ligand affinity (Kd GRWT: 1.73â nM vs GRR569Q: 4.61â nM). Tertiary structure modeling suggested a loss of hydrogen bonds between H3 and the H1-H3 loop. CONCLUSION: This is the first description of a reversible glucocorticoid resistance syndrome with effective negative feedback on corticotroph cells regarding increased plasma cortisol concentrations due to the development of mild autonomous cortisol secretion.
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Glucocorticoides , Errores Innatos del Metabolismo , Receptores de Glucocorticoides , Humanos , Hormona Adrenocorticotrópica/genética , Glucocorticoides/farmacología , Glucocorticoides/uso terapéutico , Glucocorticoides/metabolismo , Hidrocortisona , Ligandos , Mutación , Receptores de Glucocorticoides/genética , Receptores de Glucocorticoides/metabolismo , Receptores de Glucocorticoides/deficiencia , SíndromeRESUMEN
Primary glucocorticoid resistance (OMIM 615962) is a rare endocrinologic condition caused by resistance of the human glucocorticoid receptor (hGR) to glucocorticoids (GR) and characterised by general or partial insensitivity of target organs to GK. Compensatory activation of hypothalamic-pituitary-andrenal axis results in development of a various pathological conditions caused by overstimulation of adrenal glands. Clinical spectrum may range from asymptomatic cases to severe cases of mineralocorticoid and/or androgen excess. At present time, primary generalized glucocorticoid resistance has been exclusively associated with defects in the NR3C1 gene. Here, we present a case report of an adolescent patient with clinical presentation of glucocorticoid resistance confirmed by detailed endocrinologic evaluation but no confirmed mutations in the NR3C1 gene.
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Errores Innatos del Metabolismo , Receptores de Glucocorticoides , Receptores de Glucocorticoides/deficiencia , Adolescente , Humanos , Receptores de Glucocorticoides/genética , Glucocorticoides/uso terapéutico , Glándulas Suprarrenales , Errores Innatos del Metabolismo/genética , Enfermedades RarasRESUMEN
AIMS: Treatment of multiple sclerosis (MS) relapses consists of short-term administration of high-dose glucocorticoids (GCs). However, over 40% of patients show an insufficient response to GC treatment. We aimed to develop a predictive model for such GC resistance. METHODS: We performed a receiver operating characteristic (ROC) curve analysis following the transcriptomic assay of whole blood samples from stable, relapsing GC-sensitive and relapsing GC-resistant patients with MS in two different European centers. RESULTS: We identified 12 genes being regulated during a relapse and differentially expressed between GC-sensitive and GC-resistant patients with MS. Using these genes, we defined a statistical model to predict GC resistance with an area under the curve (AUC) of the ROC analysis of 0.913. Furthermore, we observed that relapsing GC-resistant patients with MS have decreased GR, DUSP1, and TSC22D3 mRNA levels compared with relapsing GC-sensitive patients with MS. Finally, we showed that the transcriptome of relapsing GC-resistant patients with MS resembles those of stable patients with MS. CONCLUSION: Predicting GC resistance would allow patients to benefit from prompt initiation of an alternative relapse treatment leading to increased treatment efficacy. Thus, we think our model could contribute to reducing disability development in people with MS.
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Errores Innatos del Metabolismo , Esclerosis Múltiple , Receptores de Glucocorticoides/deficiencia , Humanos , Esclerosis Múltiple/tratamiento farmacológico , Esclerosis Múltiple/genética , Glucocorticoides/farmacología , Glucocorticoides/uso terapéutico , Receptores de Glucocorticoides/genética , Enfermedad Crónica , Perfilación de la Expresión Génica , RecurrenciaRESUMEN
BACKGROUND: bullous dermatosis is a group of skin diseases that occur on the skin and mucous membrane, with blister and bulla as basic damage, mainly including pemphigus and bullous pemphigoid. Glucocorticoid (GC) is still the preferred drug for its treatment, but some patients respond poorly to GC and even develop glucocorticoid resistance (GCR). However, at present about the disease the understanding of the mechanisms for GCR is limited. OBJECTIVE: This study attempted to investigate the molecular mechanism of GCR in bullous dermatosis with heat shock proteins 90 (HSP90) and glucocorticoid receptor (GR) as molecular targets. METHODS: In this study, flow cytometry was used to measure and analyze the expression of HSP90 and GR in the lesions of patients with glucocorticoid-resistant bullosa dermatosis. Immunohistochemistry and immunofluorescence were used to observe the expression distribution and cell localization of HSP90 and GR. RESULTS: The expression of HSP90 in skin lesions of GCR group was significantly higher than that of glucocorticoid-sensitive (GCS) group, while the expression level of GR was lower than that of GCS group. In the epidermis, the expression and distribution of HSP90 were not different between the GCR group and the GCS group. And in the dermis, HSP90 and GR were more likely to be expressed in the nucleus in the GCR group. CONCLUSION: The overexpression and nuclear distribution of HSP90 may be related to the occurrence of GCR in patients with bullous dermatosis. And this correlation is more likely to occur in the dermis than in the epidermis.
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Dermis , Glucocorticoides , Receptores de Glucocorticoides , Enfermedades Cutáneas Vesiculoampollosas , Humanos , Dermis/metabolismo , Glucocorticoides/uso terapéutico , Proteínas HSP90 de Choque Térmico/metabolismo , Receptores de Glucocorticoides/deficiencia , Receptores de Glucocorticoides/metabolismo , Enfermedades Cutáneas Vesiculoampollosas/tratamiento farmacológicoRESUMEN
Nuclear receptors are transcription factors with important functions in a variety of physiological and pathological processes. Targeting glucocorticoid receptor (GR) activity using glucocorticoids is a cornerstone in the treatment of patients with T cell acute lymphoblastic leukemia (T-ALL), and resistance to GC-induced cell death is associated with poor outcome and a high risk for relapse. Next to ligand-binding, heterodimerization with other transcription factors presents an important mechanism for the regulation of GR activity. Here, we describe a GC-induced direct association of the Liver Receptor Homolog-1 (LRH-1) with the GR in the nucleus, which results in reciprocal inhibition of transcriptional activity. Pharmacological and molecular interference with LRH-1 impairs proliferation and survival in T-ALL and causes a profound sensitization to GC-induced cell death, even in GC-resistant T-ALL. Our data illustrate that direct interaction between GR and LRH-1 critically regulates glucocorticoid sensitivity in T-ALL opening up new perspectives for developing innovative therapeutic approaches to treat GC-resistant T-ALL.
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Leucemia-Linfoma Linfoblástico de Células T Precursoras , Receptores Citoplasmáticos y Nucleares , Receptores de Glucocorticoides , Apoptosis , Glucocorticoides/farmacología , Humanos , Errores Innatos del Metabolismo , Leucemia-Linfoma Linfoblástico de Células T Precursoras/metabolismo , Receptores Citoplasmáticos y Nucleares/genética , Receptores de Glucocorticoides/deficiencia , Receptores de Glucocorticoides/genética , Factores de TranscripciónRESUMEN
Hypertension is one of the leading causes of premature death in humans and exhibits a complex aetiology including environmental and genetic factors. Mutations within the glucocorticoid receptor (GR) can cause glucocorticoid resistance, which is characterized by several clinical features like hypercortisolism, hypokalaemia, adrenal hyperplasia and hypertension. Altered glucocorticoid receptor signalling further affects sodium and potassium homeostasis as well as blood pressure regulation and cell proliferation and differentiation that influence organ development and function. In salt-sensitive hypertension, excessive renal salt transport and sympathetic nervous system stimulation may occur simultaneously, and, thus, both the mineralocorticoid receptor (MR) and the GR-signalling may be implicated or even act interdependently. This review focuses on identified GR mutations in human primary generalized glucocorticoid resistance (PGGR) patients and their related clinical phenotype with specific emphasis on adrenal gland hyperplasia and hypertension. We compare these findings to mouse and rat mutants harbouring genetically engineered mutations to further dissect the cause and/or the consequence of clinical features which are common or different.
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Hipertensión , Receptores de Glucocorticoides , Glándulas Suprarrenales , Animales , Glucocorticoides , Humanos , Hiperplasia/genética , Hipertensión/etiología , Errores Innatos del Metabolismo , Ratones , Mutación , Ratas , Receptores de Glucocorticoides/deficiencia , Receptores de Glucocorticoides/genética , Receptores de Mineralocorticoides/genéticaAsunto(s)
Células Supresoras de Origen Mieloide , Púrpura Trombocitopénica Idiopática , Glucocorticoides , Humanos , Errores Innatos del Metabolismo , Células Supresoras de Origen Mieloide/metabolismo , Púrpura Trombocitopénica Idiopática/metabolismo , Receptores de Glucocorticoides/deficiencia , Receptores de Glucocorticoides/metabolismoRESUMEN
Glucocorticoid (GC) resistance is a poor prognostic factor in T-cell acute lymphoblastic leukaemia (T-ALL). Interleukin-7 (IL-7) mediates GC resistance via GC-induced upregulation of IL-7 receptor (IL-7R) expression, leading to increased pro-survival signalling. IL-7R reaches the cell surface via the secretory pathway, so we hypothesized that inhibiting the translocation of IL-7R into the secretory pathway would overcome GC resistance. Sec61 is an endoplasmic reticulum (ER) channel that is required for insertion of polypeptides into the ER. Here, we demonstrate that KZR-445, a novel inhibitor of Sec61, potently attenuates the dexamethasone (DEX)-induced increase in cell surface IL-7R and overcomes IL-7-induced DEX resistance.
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Leucemia-Linfoma Linfoblástico de Células T Precursoras , Canales de Translocación SEC , Citocinas/metabolismo , Dexametasona/farmacología , Glucocorticoides/farmacología , Humanos , Interleucina-7 , Errores Innatos del Metabolismo , Leucemia-Linfoma Linfoblástico de Células T Precursoras/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células T Precursoras/metabolismo , Receptores de Glucocorticoides/deficiencia , Canales de Translocación SEC/metabolismo , Linfocitos T/metabolismoRESUMEN
Background: In Cushing's syndrome (CS), chronic glucocorticoid excess (GC) and disrupted circadian rhythm lead to insulin resistance (IR), diabetes mellitus, dyslipidaemia and cardiovascular comorbidities. As undifferentiated, self-renewing progenitors of adipocytes, mesenchymal stem cells (MSCs) may display the detrimental effects of excess GC, thus revealing a promising model to study the molecular mechanisms underlying the metabolic complications of CS. Methods: MSCs isolated from the abdominal skin of healthy subjects were treated thrice daily with GCs according to two different regimens: lower, circadian-decreasing (Lower, Decreasing Exposure, LDE) versus persistently higher doses (Higher, Constant Exposure, HCE), aimed at mimicking either the physiological condition or CS, respectively. Subsequently, MSCs were stimulated with insulin and glucose thrice daily, resembling food uptake and both glucose uptake/GLUT-4 translocation and the expression of LIPE, ATGL, IL-6 and TNF-α genes were analyzed at predefined timepoints over three days. Results: LDE to GCs did not impair glucose uptake by MSCs, whereas HCE significantly decreased glucose uptake by MSCs only when prolonged. Persistent signs of IR occurred after 30 hours of HCE to GCs. Compared to LDE, MSCs experiencing HCE to GCs showed a downregulation of lipolysis-related genes in the acute period, followed by overexpression once IR was established. Conclusions: Preserving circadian GC rhythmicity is crucial to prevent the occurrence of metabolic alterations. Similar to mature adipocytes, MSCs suffer from IR and impaired lipolysis due to chronic GC excess: MSCs could represent a reliable model to track the mechanisms involved in GC-induced IR throughout cellular differentiation.
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Síndrome de Cushing , Resistencia a la Insulina , Células Madre Mesenquimatosas , Síndrome de Cushing/complicaciones , Glucocorticoides/metabolismo , Glucosa/efectos adversos , Glucosa/metabolismo , Humanos , Insulina/metabolismo , Resistencia a la Insulina/fisiología , Lipólisis , Células Madre Mesenquimatosas/metabolismo , Errores Innatos del Metabolismo , Receptores de Glucocorticoides/deficienciaRESUMEN
T-cell acute lymphoblastic leukemia (T-ALL) is a serious hematologic malignancy and glucocorticoid resistance is the main recurrent cause for a high relapsed and death rate. Here, we proposed an effective therapeutic regimen of combining gamma-secretase inhibitors (GSIs) with dexamethasone (DEX) to overcome glucocorticoid resistance. Moreover, the bone marrow targeting DT7 peptide-modified lecithin nanoparticles co-loaded with DEX and GSI (TLnp/D&G) were developed to enhance T-ALL cells recognition and endocytosis. In vitro cytotoxicity studies showed that TLnp/D&G significantly inhibited cell survival and promoted apoptosis of T-ALL cells. Mechanically, we found that GSIs promoted DEX-induced cell apoptosis by two main synergetic mechanisms: 1) GSIs significantly upregulated glucocorticoid receptor (GR) expression in T-ALL and restored the glucocorticoid-induced pro-apoptotic response. 2) Both DEX and GSI synergistically inhibited BCL2 and suppressed the survival of T-ALL cells. Furthermore, in vivo studies demonstrated that TLnp/D&G showed high bone marrow accumulation and better antileukemic efficacy both in leukemia bearing models and in systemic Notch1-induced T-ALL models, with excellent biosafety and reduced gastrointestinal toxicity. Overall, our study provides new strategies for the treatment of T-ALL and promising bone marrow targeting systems with high transformation potential.
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Nanopartículas , Leucemia-Linfoma Linfoblástico de Células T Precursoras , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Apoptosis , Línea Celular Tumoral , Dexametasona/farmacología , Glucocorticoides , Humanos , Lecitinas/farmacología , Lecitinas/uso terapéutico , Errores Innatos del Metabolismo , Péptidos/farmacología , Leucemia-Linfoma Linfoblástico de Células T Precursoras/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células T Precursoras/patología , Receptor Notch1/metabolismo , Receptores de Glucocorticoides/deficiencia , Linfocitos T/metabolismoRESUMEN
Glucocorticoid (GC) is a key drug in the treatment of B-cell precursor acute lymphoblastic leukemia (BCP-ALL), and the initial GC response is an important prognostic factor. GC receptors play an essential role in GC sensitivity, and somatic mutations of the GC receptor gene, NR3C1, are reportedly identified in some BCP-ALL cases, particularly at relapse. Moreover, associations of somatic mutations of the CREB-binding protein (CREBBP) and Wolf-Hirschhorn syndrome candidate 1 (WHSC1) genes with the GC-resistance of ALL have been suggested. However, the significance of these mutations in the GC sensitivity of BCP-ALL remains to be clarified in the intrinsic genes. In the present study, we sequenced NR3C1, WHSC1, and CREBBP genes in 99 BCP-ALL and 22 T-ALL cell lines (32 and 67 cell lines were known to be established at diagnosis and at relapse, respectively), and detected their mutations in 19 (2 cell lines at diagnosis and 15 cell lines at relapse), 26 (6 and 15), and 38 (11 and 15) cell lines, respectively. Of note, 14 BCP-ALL cell lines with the NR3C1 mutations were significantly more resistant to GC than those without mutations. In contrast, WHSC1 and CREBBP mutations were not associated with GC resistance. However, among the NR3C1 unmutated BCP-ALL cell lines, WHSC1 mutations tended to be associated with GC resistance and lower NR3C1 gene expression. Finally, we successfully established GC-resistant sublines of the GC-sensitive BCP-ALL cell line (697) by disrupting ligand binding and DNA binding domains of the NR3C1 gene using the CRISPR/Cas9 system. These observations demonstrated that somatic mutations of the NR3C1 gene, and possibly the WHSC1 gene, confer GC resistance in BCP-ALL.
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Leucemia-Linfoma Linfoblástico de Células Precursoras , Receptores de Glucocorticoides , Glucocorticoides/farmacología , Glucocorticoides/uso terapéutico , Humanos , Errores Innatos del Metabolismo , Mutación , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Receptores de Glucocorticoides/deficiencia , Receptores de Glucocorticoides/genética , Receptores de Glucocorticoides/metabolismo , RecurrenciaRESUMEN
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.
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Glucocorticoides/genética , Inflamación/genética , Errores Innatos del Metabolismo/genética , Receptores de Glucocorticoides/deficiencia , Receptores de Glucocorticoides/genética , Animales , Regulación de la Expresión Génica/genética , Glucocorticoides/metabolismo , Homeostasis/genética , Humanos , Inflamación/metabolismo , Inflamación/patología , Errores Innatos del Metabolismo/metabolismo , Errores Innatos del Metabolismo/patología , Unión Proteica/genética , Receptores de Glucocorticoides/metabolismo , Transducción de Señal/genética , Pez Cebra/genéticaRESUMEN
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.
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Glucocorticoides/metabolismo , Errores Innatos del Metabolismo/genética , Receptores de Glucocorticoides/deficiencia , Receptores de Glucocorticoides/metabolismo , Regulación hacia Abajo/efectos de los fármacos , Glucocorticoides/farmacología , Humanos , ARN Mensajero/genética , Receptores de Glucocorticoides/genéticaRESUMEN
Glucocorticoids are the final products of the neuroendocrine hypothalamic-pituitary-adrenal axis, and play an important role in the stress response to re-establish homeostasis when it is threatened, or perceived as threatened. These steroid hormones have pleiotropic actions through binding to their cognate receptor, the human glucocorticoid receptor, which functions as a ligand-bound transcription factor inducing or repressing the expression of a large number of target genes. To achieve homeostasis, glucocorticoid signaling should have an optimal effect on all tissues. Indeed, any inappropriate glucocorticoid effect in terms of quantity or quality has been associated with pathologic conditions, which are characterized by short-term or long-lasting detrimental effects. Two such conditions, the primary generalized glucocorticoid resistance and hypersensitivity syndromes, are discussed in this review article. Undoubtedly, the tremendous progress of structural, molecular, and cellular biology, in association with the continued progress of biotechnology, has led to a better and more in-depth understanding of these rare endocrinologic conditions, as well as more effective therapeutic management.
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Síndrome de Hipersensibilidad a Medicamentos/patología , Resistencia a Medicamentos/genética , Glucocorticoides/farmacología , Errores Innatos del Metabolismo/patología , Receptores de Glucocorticoides/deficiencia , Receptores de Glucocorticoides/genética , Animales , Síndrome de Hipersensibilidad a Medicamentos/etiología , Síndrome de Hipersensibilidad a Medicamentos/metabolismo , Humanos , Errores Innatos del Metabolismo/genéticaRESUMEN
Endogenous glucocorticoids (GCs) are steroid hormones that signal in virtually all cell types to modulate tissue homeostasis throughout life. Also, synthetic GC derivatives (pharmacological GCs) constitute the first-line treatment in many chronic inflammatory conditions with unquestionable therapeutic benefits despite the associated adverse effects. GC actions are principally mediated through the GC receptor (GR), a ligand-dependent transcription factor. Despite the ubiquitous expression of GR, imbalances in GC signalling affect tissues differently, and with variable degrees of severity through mechanisms that are not completely deciphered. Congenital or acquired GC hypersensitivity or resistance syndromes can impact responsiveness to endogenous or pharmacological GCs, causing disease or inadequate therapeutic outcomes, respectively. Acquired GC resistance is defined as loss of efficacy or desensitization over time, and arises as a consequence of chronic inflammation, affecting around 30% of GC-treated patients. It represents an important limitation in the management of chronic inflammatory diseases and cancer, and can be due to impairment of multiple mechanisms along the GC signalling pathway. Among them, activation of the mitogen-activated protein kinases (MAPKs) and/or alterations in expression of their regulators, the dual-specific phosphatases (DUSPs), have been identified as common mechanisms of GC resistance. While many of the anti-inflammatory actions of GCs rely on GR-mediated inhibition of MAPKs and/or induction of DUSPs, the GC anti-inflammatory capacity is decreased or lost in conditions of excessive MAPK activation, contributing to disease susceptibility in tissue- and disease- specific manners. Here, we discuss potential strategies to modulate GC responsiveness, with the dual goal of overcoming GC resistance and minimizing the onset and severity of unwanted adverse effects while maintaining therapeutic potential.
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Regulación de la Expresión Génica , Glucocorticoides/metabolismo , Sistema de Señalización de MAP Quinasas , Receptores de Glucocorticoides/genética , Receptores de Glucocorticoides/metabolismo , Animales , Enfermedades Autoinmunes/terapia , Enfermedad Crónica , Activación Enzimática , Heterocigoto , Humanos , Inflamación/metabolismo , Leucemia/terapia , Errores Innatos del Metabolismo/metabolismo , Ratones , Mutación , Polimorfismo Genético , Isoformas de Proteínas , Receptores de Glucocorticoides/deficiencia , Trastornos Respiratorios/terapia , Transducción de Señal , Enfermedades de la Piel/terapia , Resultado del TratamientoRESUMEN
The glucocorticoid receptor is a key regulator of essential physiological processes, which under the control of the Hsp90 chaperone machinery, binds to steroid hormones and steroid-like molecules and in a rather complicated and elusive response, regulates a set of glucocorticoid responsive genes. We here examine a human glucocorticoid receptor variant, harboring a point mutation in the last C-terminal residues, L773P, that was associated to Primary Generalized Glucocorticoid Resistance, a condition originating from decreased affinity to hormone, impairing one or multiple aspects of GR action. Using in vitro and in silico methods, we assign the conformational consequences of this mutation to particular GR elements and report on the altered receptor properties regarding its binding to dexamethasone, a NCOA-2 coactivator-derived peptide, DNA, and importantly, its interaction with the chaperone machinery of Hsp90.
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Glucocorticoides/genética , Proteínas HSP90 de Choque Térmico/genética , Conformación Molecular/efectos de los fármacos , Receptores de Glucocorticoides/genética , Animales , ADN/genética , Dexametasona/farmacología , Glucocorticoides/química , Proteínas HSP90 de Choque Térmico/ultraestructura , Humanos , Errores Innatos del Metabolismo/genética , Errores Innatos del Metabolismo/patología , Chaperonas Moleculares/genética , Chaperonas Moleculares/ultraestructura , Coactivador 2 del Receptor Nuclear/química , Coactivador 2 del Receptor Nuclear/genética , Péptidos/genética , Mutación Puntual/genética , Unión Proteica/genética , Receptores de Glucocorticoides/deficiencia , Receptores de Glucocorticoides/ultraestructuraRESUMEN
Endothelial cells play a key role in the regulation of disease. Defective regulation of endothelial cell homeostasis may cause mesenchymal activation of other endothelial cells or neighboring cell types, and in both cases contributes to organ fibrosis. Regulatory control of endothelial cell homeostasis is not well studied. Diabetes accelerates renal fibrosis in mice lacking the endothelial glucocorticoid receptor (GR), compared to control mice. Hypercholesterolemia further enhances severe renal fibrosis. The fibrogenic phenotype in the kidneys of diabetic mice lacking endothelial GR is associated with aberrant cytokine and chemokine reprogramming, augmented Wnt signaling and suppression of fatty acid oxidation. Both neutralization of IL-6 and Wnt inhibition improve kidney fibrosis by mitigating mesenchymal transition. Conditioned media from endothelial cells from diabetic mice lacking endothelial GR stimulate Wnt signaling-dependent epithelial-to-mesenchymal transition in tubular epithelial cells from diabetic controls. These data demonstrate that endothelial GR is an essential antifibrotic molecule in diabetes.
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Nefropatías Diabéticas/patología , Endotelio/patología , Hipercolesterolemia/complicaciones , Túbulos Renales/patología , Receptores de Glucocorticoides/deficiencia , Adrenalectomía , Animales , Diabetes Mellitus Experimental/sangre , Diabetes Mellitus Experimental/inducido químicamente , Diabetes Mellitus Experimental/complicaciones , Diabetes Mellitus Experimental/patología , Nefropatías Diabéticas/sangre , Nefropatías Diabéticas/etiología , Células Endoteliales/patología , Endotelio/citología , Transición Epitelial-Mesenquimal/efectos de los fármacos , Transición Epitelial-Mesenquimal/genética , Ácidos Grasos/metabolismo , Fibrosis , Glucocorticoides/metabolismo , Humanos , Hipercolesterolemia/sangre , Hipercolesterolemia/etiología , Hipercolesterolemia/patología , Interleucina-6/antagonistas & inhibidores , Interleucina-6/metabolismo , Túbulos Renales/citología , Masculino , Ratones , Ratones Noqueados para ApoE , Oxidación-Reducción , Receptores de Glucocorticoides/genética , Estreptozocina/administración & dosificación , Estreptozocina/toxicidad , Vía de Señalización Wnt/efectos de los fármacos , Vía de Señalización Wnt/genéticaRESUMEN
We describe the characterisation and validation of an androgen receptor (AR) transactivation assay for detection of AR agonists and antagonists using a stably transfected human prostate cancer cell line. This 22Rv1/mouse mammary tumour virus glucocorticoid knock-out cell line based AR transactivation assay was validated by criteria in Organisation for Economic Cooperation and Development Guidance Document 34 to determine if the assay performed equally well to the AR EcoScreen Assay included in Test Guideline for AR Transactivation (OECD TG 458). There was no Glucocorticoid Receptor (GR) crosstalk, and no changes in the AR DNA sequence in cells after the successful knock out of GR. Subsequently, the concordance of classifications of the 22 test chemicals was 100% in all laboratories. The AR agonistic and antagonistic inter-laboratory coefficients of variation based on log[10% effect for 10 nM DHT, PC10] and log[inhibitory response of 800 pM DHT by at 30%, IC30] from comprehensive tests were 2.75% and 2.44%, respectively. The AR agonist/antagonist test chemical classifications were consistent across AR EcoScreen ARTA assay data for 82/89%, and the balanced accuracy, sensitivity, and specificity were 83/90%, 88/100% and 78/80%, respectively. This assay was successfully validated and was approved for inclusion in TG 458 in 2020.
Asunto(s)
Antagonistas de Receptores Androgénicos/farmacología , Andrógenos/farmacología , Evaluación Preclínica de Medicamentos/métodos , Receptores Androgénicos/metabolismo , Animales , Línea Celular Tumoral , Técnicas de Inactivación de Genes , Humanos , Virus del Tumor Mamario del Ratón , Ratones , Receptores de Glucocorticoides/deficiencia , Receptores de Glucocorticoides/genética , Reproducibilidad de los Resultados , Activación Transcripcional/efectos de los fármacosRESUMEN
OBJECTIVE: The glucocorticoid receptor (GR) is a member of the nuclear receptor family that controls key biological processes in the cardiovascular system and has recently been shown to modulate Wnt signaling in endothelial cells. Wnt/ß-catenin signaling has been demonstrated to be crucial in the process of angiogenesis. In the current study, we studied whether GR could regulate angiogenesis via the Wnt/ß-catenin pathway. APPROACH AND RESULTSA: Key components of the Wnt/ß-catenin pathway were evaluated using quantitative PCR and Western blot in the presence or absence of GR. Enhanced angiogenesis was found in GR deficiency in vitro and confirmed with cell viability assays, proliferation assays and tube formation assays. Consistent with these in vitro findings, endothelial cell-specific GR loss GR in vivo promoted angiogenesis in both a hind limb ischemia model and sponge implantation assay. Results were further verified in a novel mouse model lacking endothelial LRP5/6, a key receptor in canonical Wnt signaling, and showed substantially suppressed angiogenesis using these same in vitro and in vivo assays. To further investigate the mechanism of GR regulation of Wnt signaling, autophagy flux was investigated in endothelial cells by visualizing auto phagolysosomes as well as by assessing P62 degradation and LC3B conversion. Results indicated that potentiated autophagy flux participated in GR-Wnt regulation. CONCLUSIONS: Lack of endothelial GR triggers autophagy flux, leads to activation of Wnt/ß-catenin signaling and promotes angiogenesis. There may also be a synergistic interaction between autophagy and Wnt/ß-catenin signaling.