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1.
BMJ Case Rep ; 17(8)2024 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-39179263

RESUMO

A toddler presented with recurrent subcutaneous abscesses, otitis media and pneumonia, requiring frequent hospitalisations and intravenous antimicrobials. He also had oral thrush and difficulty in gaining weight; hence, an underlying inborn error of immunity (IEI) was strongly suspected. The complete haemogram showed leucocytosis with neutrophilic predominance. Both erythrocyte sedimentation rate and C reactive protein were elevated. Klebsiella pneumoniae was isolated from blood culture. The dihydrorhodamine-123 assay was negative, and the immunoglobulin profile showed an increased IgG level. Whole exome sequencing revealed a novel homozygous pathogenic variation in the IL-17RA gene (c.2563G>A, p. Asp855Asn). He showed remarkable improvement following intravenous colistin and fluconazole with complete resolution of abscesses. Thus, it is prudent to consider the possibility of IL-17RA deficiency in children with a history of recurrent abscesses, skin ulcerations and pneumonia after excluding the common groups of IEI.


Assuntos
Abscesso , Receptores de Interleucina-17 , Pré-Escolar , Humanos , Masculino , Abscesso/diagnóstico , Abscesso/tratamento farmacológico , Abscesso/microbiologia , Antibacterianos/uso terapêutico , Infecções por Klebsiella/diagnóstico , Infecções por Klebsiella/tratamento farmacológico , Infecções por Klebsiella/complicações , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/isolamento & purificação , Pneumonia/tratamento farmacológico , Pneumonia/diagnóstico , Pneumonia/microbiologia , Receptores de Interleucina-17/genética , Recidiva
2.
Eur J Pharmacol ; : 176945, 2024 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-39182547

RESUMO

The nuclear receptor Nur77 is a transcription factor belonging to the NR4A subfamily. Upon activation, it regulates a wide array of biological and pathophysiological processes by modulating the expression of its target genes. Previous findings have classified Nur77 as an orphan receptor because of the discovery of a structurally atypical ligand-binding domain and the lack of identification of an endogenous ligand. Nevertheless, recent studies have uncovered several endogenous, natural, and small synthetic molecules that can bind to and activate Nur77. However, developing selective and potent Nur77 activators remains a significant challenge. The discovery of novel and potential small synthetic molecules that modulate Nur77 activity will facilitate therapeutic interventions of Nur77 against several human diseases. In this study, we have reported the development of a novel and effective Nur77 ligand. Our data show that (1E,4E)-1,5-di(pyrazin-2-yl)penta-1,4-dien-3-one (PB) induces Nur77 transcriptional activity by interacting with a putative Nur77 ligand binding site by forming solid hydrogen bonding. Calculated chemical parameters denote that PB has sophisticated chemical features that will enhance its interaction with the Nur77 ligand-binding domain. Molecular docking simulations showed that PB fits in the Nur77 putative ligand binding site with solid hydrogen bonding, and molecular dynamics simulations indicate that PB binding would stabilize the Nur77 ligand binding domain. Further, in vitro studies revealed that PB increases Nur77 nuclear expression and activity, inhibits cigarette smoke-induced inflammatory phenotype of airway epithelial cells, and protects against apoptosis. These findings provide insights into developing an effective Nur77 small-molecule activator which could be developed into a therapeutic agent against inflammatory diseases.

4.
Cureus ; 16(6): e62455, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-39022466

RESUMO

Genodermatoses encompass a spectrum of hereditary skin disorders stemming from mutations in genes pivotal for skin development, structure, and function. This study investigated the prevalence, gender predilection, and inheritance patterns of genodermatoses in a tertiary-level hospital through a one-year observational study. Among 157,051 dermatology outpatient department patients, 105 cases of genodermatoses were diagnosed, yielding a prevalence rate of 0.067%. Hamartoneoplastic syndromes and inherited disorders of cornification were the most prevalent subgroups, with neurofibromatosis type 1 and tuberous sclerosis complex 1 leading within these categories. The average age at presentation varied among different subgroups. A 2:1 male-to-female ratio was observed across all subgroups. Autosomal dominant inheritance was predominant. A positive family history in 46 cases and consanguinity among parents in 28 instances was reported. Genodermatoses pose diagnostic challenges due to their clinical complexity and rarity, which is compounded by limited epidemiological data. Molecular diagnosis advancements offer insights into genotype-phenotype correlations and facilitate genetic counseling and prenatal diagnosis (PND). Raising awareness among healthcare professionals and the public is critical for improving the quality of life for affected individuals.

6.
Cureus ; 16(3): e57312, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38690488

RESUMO

Erythema nodosum leprosum is a type 3 hypersensitivity reaction that often presents with transient eruptions of red papules, plaques, and nodules. A 52-year-old female presented with multiple joint pain that was being treated as rheumatoid arthritis (RA), but through clinical examination, she was found to have Hansen's disease with a type 2 reaction. Hence, the importance of a thorough clinical examination is a must for the timely and correct diagnosis of patients suffering from Hansen's disease.

7.
Cureus ; 16(3): e56600, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38646262

RESUMO

Reticulate pigmentary disorders are autosomal dominant pigmentary disorders caused by abnormalities in the keratin 5 and keratin 14 genes. Here, we report three cases of reticulate hyperpigmentation disorders with clinical overlaps of the reticulate acropigmentation of Kitamura, Dowling-Degos disease (DDD), and dyschromatosis symmetrica hereditaria (DSH), all three having limited treatment options.

8.
Semin Neurol ; 43(3): 480-492, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37517406

RESUMO

Unruptured intracranial aneurysms are often discovered incidentally on noninvasive imaging. As use of noninvasive imaging has increased, our understanding of the presumed prevalence of intracranial aneurysms in adults has increased. Incidentally found aneurysms are often asymptomatic; however, they can rarely rupture and cause life-threatening illness. Elective treatment of intracranial aneurysms carries risks which need to be considered along with patient-specific factors (e.g., anatomy, medical comorbidities, personal preferences). In this article, we review the natural history, risk factors for cerebral aneurysm formation and rupture, evidence for medical management, and the safety profile and efficacy of available endovascular treatment options.


Assuntos
Aneurisma Intracraniano , Adulto , Humanos , Aneurisma Intracraniano/diagnóstico por imagem , Aneurisma Intracraniano/epidemiologia , Prevalência , Fatores de Risco
9.
Indian J Ophthalmol ; 69(9): 2437-2440, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34427239

RESUMO

PURPOSE: Alcohol delamination of the corneal epithelium (ADCE) is a therapeutic option for patients with recurrent corneal erosion (RCE) who do not respond to nonsurgical management of lubricants and extended wear contact lens. The aim of the study is to report on three-year efficacy and safety of ADCE for RCE of traumatic etiology. METHODS: This is a retrospective review of consecutive patients who underwent ADCE for traumatic RCE in a local hospital between January 2010 and January 2020. The outcomes at a 3-year follow-up review are included. Nonsurgical therapy used; intra- and postoperative complications were recorded. ADCE was only offered to those who remained symptomatic despite maximum topical lubrications and/or extended wear contact lens. Success was defined as the absence of recurrence of corneal erosion. RESULTS: Twenty-six eyes of 26 patients with RCE caused by trauma underwent ADCE. The mean age of patients was 39 years. The follow-up period was a minimum of 36 months. Three eyes (11.5%) had recurrence of corneal erosion after ADCE at the 3-year follow-up. Recurrence was noted at months 2, 23, and 36 postoperatively in these patients. All patients reported significant improvement in symptoms associated with recurrent erosion. Ten eyes (38.5%) stopped all topical lubricants postoperatively. No intra- or postoperative complications were noted in our study. CONCLUSION: This study documents the long-term safety and efficacy of alcohol delamination of corneal epithelium at 3 years for patients with RCE of traumatic origin.


Assuntos
Distrofias Hereditárias da Córnea , Úlcera da Córnea , Epitélio Corneano , Adulto , Humanos , Recidiva , Estudos Retrospectivos
10.
Indian J Ophthalmol ; 69(5): 1052-1060, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33913831

RESUMO

The incidence of leishmaniasis is reported to be up to 1 million per year. To date, there has been no comprehensive review describing the diversity of clinical presentations of ocular leishmaniasis (OL) and its treatment. This systematic review aims to address this knowledge gap and provide a summary of the clinical presentation, natural course, and treatment options for OL. Our study identified a total of 57 published articles as describing cases of OL involving: adnexa (n = 26), orbit (n = 1), retina (n = 7), uvea (n = 18) and cornea (n = 6). Though well described and easily treated, palpebral leishmaniasis is often misdiagnosed and may lead to chronic issues if untreated. The retinal manifestations of Leishmaniasis consist of self-resolving hemorrhages secondary to thrombocytopenia. Two main uveitis etiologies have been identified: uveitis in the context of active Leishmanial infection (associated with immunosuppression) and uveitis occurring as an immune reconstitution syndrome. Corneal involvement in most geographic areas generally follows an aggressive course, most often ending in corneal perforation if left untreated. In the Americas, a chronic indolent interstitial keratitis may also occur. Topical steroids are of little use in keratitis (systemic antileishmanials being the cornerstone of treatment). However, these are essential in cases of uveitis, with or without concomitant systemic antileishmanial therapy. In conclusion, though ocular involvement in Leishmaniasis is rare, severe sight-threatening consequences follow if left untreated. Early diagnosis, enthusiastic follow-up and aggressive treatment are essential for good outcomes.


Assuntos
Perfuração da Córnea , Ceratite , Leishmaniose , Uveíte , Córnea , Humanos
11.
Arch Biochem Biophys ; 695: 108620, 2020 11 30.
Artigo em Inglês | MEDLINE | ID: mdl-33038311

RESUMO

Potential health benefits of consuming tea are thought to include anti-inflammatory actions of its constituent flavonoids including catechins, which are well-recognized antioxidants. We analyzed and discovered a novel mechanism by which epigallocatechin gallate (EGCG), the most abundant polyphenol in tea and a putative health-promoting constituent, inhibits activation of the nuclear transcription factor NF-κB, which mediates inflammatory responses to cytokines and other agents. We found that EGCG inhibits NF-κB-p65 transcriptional activity, by preventing NF-κB-p65 binding to κBs in normal human bronchial epithelial cells. We also analyzed the chemical mechanism by which EGCG binds directly to NF-κB-p65, and found that it involves covalent reaction via enones within EGCG ring structures, as the oxidizer diamide, which prevents 1, 4-addition reactions, blocked adduct-forming reaction of biotinylated EGCG with NF-κB-p65. Such blockade was inhibited by competing unlabeled EGCG. Furthermore, such covalent binding reflected irreversible reaction of EGCG with sulfhydryls of NF-κB-p65, as it was inhibited by glutathione but not reversible by it. We identified the reactive sulfhydryl moiety as that of cysteine, as S-carboxymethylation to block cysteine sulfhydryls prevented NF-κB-p65-Cys-alkylation reaction with EGCG. We also tested if EGCG can inhibit NF-κB-p65 binding to DNA within the nucleus, after its phosphorylation and translocation (activation). EGCG did not alter intranuclear phosphorylation levels of NF-κB-p65, but strongly repressed DNA-binding ability of activated NF-κB-p65, indicating that EGCG inhibits NF-κB-p65 DNA binding activity even without altering NF-κB-p65 phosphorylation or expression. These findings thus reveal a novel mechanism by which EGCG inhibits transcriptional activity of NF-κB-p65, that may potentially contribute to anti-inflammatory and health-promoting effects of EGCG and consumption of tea.


Assuntos
Brônquios/metabolismo , Catequina/análogos & derivados , Células Epiteliais/metabolismo , Fator de Transcrição RelA/metabolismo , Ativação Transcricional/efeitos dos fármacos , Catequina/química , Catequina/farmacologia , Linhagem Celular , Humanos , Fosforilação/efeitos dos fármacos , Chá/química
12.
Life Sci ; 259: 118260, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32795541

RESUMO

Cigarette smoke (CS), the major risk factor of chronic obstructive pulmonary disease (COPD), contains numerous free radicals that can cause oxidative stress and exaggerated inflammatory responses in the respiratory system. Lipid peroxidation which is oxidative degradation of polyunsaturated fatty acids and results in cell damage has also been associated with COPD pathogenesis. Increased levels of lipid peroxidation as well as its end product 4-hydroxynonenal have indeed been detected in COPD patients. Additionally, reactive oxygen species such as those contained in CS can activate nuclear factor-κB signaling pathway, initiating cascades of proinflammatory mediator expression. As emerging evidence attests to the antioxidative and anti-inflammatory properties of tea catechins, we sought to determine whether epigallocatechin gallate, the most abundant tea catechin, can provide protection against oxidative stress, lipid peroxidation, and inflammatory responses caused by CS. We found that EGCG treatment blocked cigarette smoke extract (CSE)-induced oxidative stress as indicated by decreased production and accumulation of reactive oxygen species in airway epithelial cells (AECs). Likewise, lipid peroxidation in CSE-stimulated AECs was suppressed by EGCG. Our findings further suggest that EGCG sequestered 4-hydroxynonenal and interfered with its protein adduct formation. Lastly, we show that EGCG inhibited nuclear factor-κB activation and the downstream expression of proinflammatory mediators. In summary, our study describing the antioxidative and anti-inflammatory effects of EGCG in CSE-exposed AECs provide valuable information about the therapeutic potential of this tea catechin for COPD.


Assuntos
Células Epiteliais Alveolares/efeitos dos fármacos , Catequina/análogos & derivados , Fumar Cigarros/tratamento farmacológico , Aldeídos/farmacologia , Células Epiteliais Alveolares/metabolismo , Anti-Inflamatórios/farmacologia , Antioxidantes/farmacologia , Brônquios/metabolismo , Catequina/metabolismo , Catequina/farmacologia , Linhagem Celular , Fumar Cigarros/efeitos adversos , Fumar Cigarros/fisiopatologia , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Humanos , Inflamação/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , NF-kappa B/metabolismo , Oxirredução/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Alvéolos Pulmonares/metabolismo , Doença Pulmonar Obstrutiva Crônica/tratamento farmacológico , Espécies Reativas de Oxigênio , Transdução de Sinais/efeitos dos fármacos , Fumaça/efeitos adversos , Fumar/efeitos adversos
13.
Life Sci ; 258: 118136, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32726662

RESUMO

The endothelium is a critical regulator of vascular homeostasis, controlling vascular tone and permeability as well as interactions of leukocytes and platelets with blood vessel walls. Consequently, endothelial dysfunction featuring inflammation and reduced vasodilation are considered central to cardiovascular disease (CVD) pathogenesis and have become a therapeutic area of focus. Type II endothelial cell (EC) activation by stress-related stimuli such as tumor necrosis factor-α (TNF-α) initiates the nuclear factor-κB (NF-κB) signaling pathway, a master regulator of inflammatory responses. Because dysregulated NF-κB signaling has been tightly linked to several CVDs, EC-specific inhibition of NF-κB represents an attractive pharmacological strategy. As accumulating evidence highlights the clinical benefits of tea catechin for multiple diseases including CVDs, we sought to determine whether the tea catechin epigallocatechin gallate (EGCG) that displays antioxidative, anti-inflammatory, hypolipidemic, anti-thrombogenic, and anti-hypertensive properties offers protection against CVDs by suppressing the canonical NF-κB pathway. Our findings indicate that EGCG downregulates multiple components of the TNF-α-induced NF-κB signaling pathway and thereby reduces the consequent increase in inflammatory gene transcription and protein expression. Furthermore, EGCG blocked type II EC activation, evidenced by diminished EC leakage and monocyte adhesion in EGCG-treated cells. In summary, our study advances knowledge of EGCG's anti-inflammatory effects on the NF-κB pathway and hence its benefits on endothelial health, supporting its therapeutic potential for CVDs.


Assuntos
Catequina/análogos & derivados , Vasos Coronários/patologia , Células Endoteliais/patologia , Inflamação/tratamento farmacológico , Catequina/farmacologia , Catequina/uso terapêutico , Adesão Celular/efeitos dos fármacos , Permeabilidade da Membrana Celular/efeitos dos fármacos , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Humanos , Inflamação/genética , Inflamação/patologia , Mediadores da Inflamação/metabolismo , Monócitos/efeitos dos fármacos , Monócitos/patologia , NF-kappa B/metabolismo , Fator de Necrose Tumoral alfa/metabolismo
14.
Clin Sci (Lond) ; 134(9): 1063-1079, 2020 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-32369100

RESUMO

Asthma is a chronic disease of the airways that has long been viewed predominately as an inflammatory condition. Accordingly, current therapeutic interventions focus primarily on resolving inflammation. However, the mainstay of asthma therapy neither fully improves lung function nor prevents disease exacerbations, suggesting involvement of other factors. An emerging concept now holds that airway remodeling, another major pathological feature of asthma, is as important as inflammation in asthma pathogenesis. Structural changes associated with asthma include disrupted epithelial integrity, subepithelial fibrosis, goblet cell hyperplasia/metaplasia, smooth muscle hypertrophy/hyperplasia, and enhanced vascularity. These alterations are hypothesized to contribute to airway hyperresponsiveness, airway obstruction, airflow limitation, and progressive decline of lung function in asthmatic individuals. Consequently, targeting inflammation alone does not suffice to provide optimal clinical benefits. Here we review asthmatic airway remodeling, focusing on airway epithelium, which is critical to maintaining a healthy respiratory system, and is the primary defense against inhaled irritants. In asthma, airway epithelium is both a mediator and target of inflammation, manifesting remodeling and resulting obstruction among its downstream effects. We also highlight the potential benefits of therapeutically targeting airway structural alterations. Since pathological tissue remodeling is likewise observed in other injury- and inflammation-prone tissues and organs, our discussion may have implications beyond asthma and lung disease.


Assuntos
Remodelação das Vias Aéreas/efeitos dos fármacos , Antiasmáticos/farmacologia , Asma/fisiopatologia , Inflamação/tratamento farmacológico , Animais , Asma/tratamento farmacológico , Epitélio/efeitos dos fármacos , Humanos , Inflamação/fisiopatologia , Pulmão/efeitos dos fármacos , Pulmão/fisiopatologia
15.
Cureus ; 12(4): e7505, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32373408

RESUMO

Primitive neuroectodermal tumors (PNET, previously referred to as peripheral neuroepithelioma) are rare malignant tumors with various degrees of differentiation belonging to the Ewing's family of sarcomas. They are classified as round cell tumors arising from soft tissues. In rare instances, PNETs may arise from solid organs containing neuroendocrine cells of kidney, bladder, heart, lungs, parotid glands and pancreas. Most cases occur in the second decade of life with a slight preponderance in males. PNET of the pancreas is an aggressive tumor with multiple recurrences and a relatively poor prognosis. These tumors should be considered in the differential diagnosis, especially in a diagnosed pancreatic tumor in individuals less than 35 years of age. Due to the nature of the tumor, surgery with subsequent chemoradiation are widely accepted modalities despite the poor prognosis. In this article, we review 25 cases of extraosseous Ewing's sarcoma (ES) of the pancreas which to the best of our knowledge, enlists most cases reported in the literature thus far.

16.
PLoS One ; 15(2): e0229256, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32084204

RESUMO

Cigarette smoke (CS) contains multiple gaseous and particulate materials that can cause lung inflammation, and smoking is the major cause of chronic obstructive pulmonary disease (COPD). We sought to determine the mechanisms of how CS triggers lung inflammation. Nur77, a nuclear hormone receptor belonging to the immediate-early response gene family, controls inflammatory responses, mainly by suppressing the NF-κB signaling pathway. Because it is unknown if Nur77's anti-inflammatory role modulates COPD, we assessed if and how Nur77 expression and activity are altered in CS-induced airway inflammation. In lung tissues and bronchial epithelial cells from COPD patients, we found Nur77 was downregulated. In a murine model of CS-induced airway inflammation, CS promoted lung inflammation and also reduced Nur77 activity in wild type (WT) mice, whereas lungs of Nur77-deficient mice showed exaggerated CS-induced inflammatory responses. Our findings in in vitro studies of human airway epithelial cells complemented those in vivo data in mice, together showing that CS induced threonine-phosphorylation of Nur77, which is known to interfere with its anti-inflammatory functions. In summary, our findings point to Nur77 as an important regulator of CS-induced inflammatory responses and support the potential benefits of Nur77 activation for COPD treatment.


Assuntos
Regulação para Baixo/efeitos dos fármacos , Nicotiana/química , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/genética , Doença Pulmonar Obstrutiva Crônica/genética , Fumaça/efeitos adversos , Animais , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Humanos , Inflamação/genética , Pulmão/patologia , Camundongos , Fosforilação/efeitos dos fármacos , Doença Pulmonar Obstrutiva Crônica/patologia , Treonina/metabolismo
17.
Artigo em Inglês | MEDLINE | ID: mdl-32021151

RESUMO

Background: Glucocorticoids are commonly prescribed to treat inflammation of the respiratory system; however, they are mostly ineffective for controlling chronic obstructive pulmonary disease (COPD)-associated inflammation. This study aimed to elucidate the molecular mechanisms responsible for such glucocorticoid inefficacy in COPD, which may be instrumental to providing better patient outcomes. Roflumilast is a selective phosphodiesterase-4 (PDE4) inhibitor with anti-inflammatory properties in severe COPD patients who have a history of exacerbations. Roflumilast has a suggested ability to mitigate glucocorticoid resistance, but the mechanism is unknown. Methods: To understand the mechanism that mediates roflumilast-induced restoration of glucocorticoid sensitivity in COPD, we tested the role of glucocorticoid receptor α (GRα). Roflumilast's effects on GRα expression and transcriptional activity were assessed in bronchial epithelial cells from COPD patients. Results: We found that both GRα expression and activity are downregulated in bronchial epithelial cells from COPD patients and that roflumilast stimulates both GRα mRNA synthesis and GRα's transcriptional activity in COPD bronchial epithelial cells. We also demonstrate that roflumilast enhances dexamethasone's ability to suppress pro-inflammatory mediator production, in a GRα-dependent manner. Discussion: Our findings highlight the significance of roflumilast-induced GRα upregulation for COPD therapeutic strategies by revealing that roflumilast restores glucocorticoid sensitivity by sustaining GRα expression.


Assuntos
Aminopiridinas/farmacologia , Benzamidas/farmacologia , Dexametasona/farmacologia , Células Epiteliais/efeitos dos fármacos , Glucocorticoides/farmacologia , Pulmão/efeitos dos fármacos , Inibidores da Fosfodiesterase 4/farmacologia , Doença Pulmonar Obstrutiva Crônica/tratamento farmacológico , Receptores de Glucocorticoides/agonistas , Células Cultivadas , Ciclopropanos/farmacologia , Resistência a Medicamentos , Células Epiteliais/metabolismo , Humanos , Mediadores da Inflamação/metabolismo , Interleucina-8/metabolismo , Pulmão/metabolismo , Pulmão/fisiopatologia , Doença Pulmonar Obstrutiva Crônica/genética , Doença Pulmonar Obstrutiva Crônica/metabolismo , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Receptores de Glucocorticoides/genética , Receptores de Glucocorticoides/metabolismo , Fator de Transcrição RelA/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Regulação para Cima
18.
Biochem J ; 476(19): 2757-2767, 2019 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-31492735

RESUMO

Nur77 is a transcription factor belonging to the NR4A subfamily of nuclear hormone receptors. Upon induction, Nur77 modulates the expression of its target genes and controls a variety of biological and pathophysiological processes. Prior research that revealed a structurally atypical ligand-binding domain (LBD) and failed to locate an endogenous ligand had led to a classification of Nur77 as an orphan receptor. However, several more recent studies indicate that small synthetic molecules and unsaturated fatty acids can bind to Nur77. Discovery of additional endogenous ligands will facilitate our understanding of the receptor's functions and regulatory mechanisms. Our data have identified prostaglandin A2 (PGA2), a cyclopentenone prostaglandin (PG), as such a ligand. Cyclopentenone PGs exert their biological effects primarily by forming protein adducts via the characteristic electrophilic ß-carbon(s) located in their cyclopentenone rings. Our data show that PGA2 induces Nur77 transcriptional activity by forming a covalent adduct between its endocyclic ß-carbon, C9, and Cys566 in the receptor's LBD. The importance of this endocyclic ß-carbon was substantiated by the failure of PGs without such electrophilic properties to react with Nur77. Calculated chemical properties and data from reactive molecular dynamic simulations, intrinsic reaction co-ordinate modeling, and covalent molecular docking also corroborate the selectivity of PGA2's C9 ß-carbon towards Nur77's Cys. In summary, our molecular, chemical, and structural characterization of the PGA2-Nur77 interaction provides the first evidence that PGA2 is an endogenous Nur77 agonist.


Assuntos
Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/agonistas , Prostaglandinas A/química , Prostaglandinas A/fisiologia , Linhagem Celular , Humanos , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/metabolismo , Prostaglandinas A/metabolismo , Ligação Proteica , Domínios Proteicos
20.
Am J Pathol ; 189(3): 482-491, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30414411

RESUMO

The transcription factor Nur77 belongs to the NR4A subfamily of nuclear hormone receptors. It features an atypical ligand-binding site that precludes canonical ligand binding, leading to the designation orphan nuclear receptor. However, recent studies show that small molecules can interact with the receptor and modulate its activity by inducing a conformational change in the Nur77 ligand-binding site. Nur77 expression and activation are rapidly induced by various physiological and pathologic stimuli. Once expressed, Nur77 initiates transcriptional activity and modulates expression of its target genes. Both in vitro and in vivo evidence shows that Nur77 dampens the immune response to proinflammatory stimuli, such as tumor necrosis factor-α, Toll-like receptor ligands, and oxidized lipids, primarily by suppressing NF-κB signaling. Although studies focusing on Nur77's role in lung pathophysiology are currently incomplete, available data support its involvement in the pathogenesis of lung diseases, including asthma, acute lung injury, and pulmonary fibrosis, and thus suggest a therapeutic potential for Nur77 activation in these diseases. This review addresses the mechanisms that control Nur77 as well as its known roles in inflammation-related lung diseases. Evidence regarding the therapeutic potential of Nur77-targeting molecules will also be presented. Although current knowledge is limited, additional research followed by clinical studies may firmly identify Nur77 as a pharmacologic target for inflammation-related lung diseases.


Assuntos
Pneumopatias/metabolismo , Pulmão/metabolismo , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/metabolismo , Transdução de Sinais , Transcrição Gênica , Animais , Humanos , Inflamação/metabolismo , Inflamação/patologia , Pulmão/patologia , Pneumopatias/patologia , Pneumopatias/terapia , NF-kappa B/biossíntese , Receptores Toll-Like/biossíntese , Fator de Necrose Tumoral alfa/biossíntese
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