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1.
Curr Top Microbiol Immunol ; 436: 337-347, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36243851

RESUMO

Aberrant overactivation of the immune system can give rise to chronic and persistent self-attack, culminating in autoimmune disease. This is currently managed therapeutically using potent immunosuppressive and anti-inflammatory drugs. Class I phosphoinositide-3-kinases (PI3Ks) have been identified as ideal therapeutic targets for autoimmune diseases given their wide-ranging roles in immunological processes. Although progress has been hampered by issues such as poor drug tolerance and drug resistance, several PI3K inhibitors have now received regulatory approval with many others in development, including several intended to suppress the immune response in autoimmune and inflammatory diseases. This chapter reviews the evidence for contribution of aberrant PI3K activity to a range of autoimmune diseases (rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis and type I diabetes) and possible therapeutic application of isoform-specific PI3K inhibitors as immunosuppressive drugs.


Assuntos
Doenças Autoimunes , Fosfatidilinositol 3-Quinases , Doenças Autoimunes/tratamento farmacológico , Humanos , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositóis/uso terapêutico , Inibidores de Fosfoinositídeo-3 Quinase , Isoformas de Proteínas/uso terapêutico
2.
Br J Cancer ; 124(10): 1618-1620, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33723395
3.
J Immunol ; 198(9): 3679-3689, 2017 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-28363904

RESUMO

H2O2 is an early danger cue required for innate immune cell recruitment to wounds. To date, little is known about whether H2O2 is required for the migration of human adaptive immune cells to sites of inflammation. However, oxidative stress is known to impair T cell activity, induce actin stiffness, and inhibit cell polarization. In this study, we show that low oxidative concentrations of H2O2 also impede chemokinesis and chemotaxis of previously activated human T cells to CXCL11, but not CXCL10 or CXCL12. We show that this deficiency in migration is due to a reduction in inflammatory chemokine receptor CXCR3 surface expression and cellular activation of lipid phosphatase SHIP-1. We demonstrate that H2O2 acts through an Src kinase to activate a negative regulator of PI3K signaling, SHIP-1 via phosphorylation, providing a molecular mechanism for H2O2-induced chemotaxis deficiency. We hypothesize that although H2O2 serves as an early recruitment trigger for innate immune cells, it appears to operate as an inhibitor of T lymphocyte immune adaptive responses that are not required until later in the repair process.


Assuntos
Movimento Celular , Quimiocina CXCL11/metabolismo , Peróxido de Hidrogênio/farmacologia , Terapia de Imunossupressão , Linfócitos T/efeitos dos fármacos , Actinas/metabolismo , Imunidade Adaptativa , Adulto , Idoso , Movimento Celular/efeitos dos fármacos , Células Cultivadas , Feminino , Humanos , Imunidade Inata/efeitos dos fármacos , Masculino , Pessoa de Meia-Idade , Estresse Oxidativo/efeitos dos fármacos , Fosfatidilinositol 3-Quinases/metabolismo , Fosfatidilinositol-3,4,5-Trifosfato 5-Fosfatases/metabolismo , Receptores CXCR3/metabolismo , Transdução de Sinais , Linfócitos T/imunologia , Adulto Jovem , Quinases da Família src/metabolismo
4.
Immunity ; 30(3): 315-7, 2009 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-19303383

RESUMO

In this issue of Immunity, Shulman et al. (2009) describe shear-facilitated chemokine-induced adhesive filopodia on crawling T lymphocytes that scan the endothelial surface for potential sites of transendothelial migration. These filopodia facilitate a novel millipede-like mode of lymphocyte locomotion over endothelial cells prior to extravasation.


Assuntos
Movimento Celular , Células Endoteliais/imunologia , Linfócitos/fisiologia , Pseudópodes/fisiologia , Animais , Quimiocinas/farmacologia , Humanos , Linfócitos/imunologia , Modelos Biológicos , Pseudópodes/efeitos dos fármacos
5.
Differentiation ; 93: 39-49, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-27875772

RESUMO

Barrett's metaplasia is the only known morphological precursor to oesophageal adenocarcinoma and is characterized by replacement of stratified squamous epithelium by columnar epithelium. The cell of origin is uncertain and the molecular mechanisms responsible for the change in cellular phenotype are poorly understood. We therefore explored the role of two transcription factors, Cdx2 and HNF4α in the conversion using primary organ cultures. Biopsy samples from cases of human Barrett's metaplasia were analysed for the presence of CDX2 and HNF4α. A new organ culture system for adult murine oesophagus is described. Using this, Cdx2 and HNF4α were ectopically expressed by adenoviral infection. The phenotype following infection was determined by a combination of PCR, immunohistochemical and morphological analyses. We demonstrate the expression of CDX2 and HNF4α in human biopsy samples. Our oesophageal organ culture system expressed markers characteristic of the normal SSQE: p63, K14, K4 and loricrin. Ectopic expression of HNF4α, but not of Cdx2 induced expression of Tff3, villin, K8 and E-cadherin. HNF4α is sufficient to induce a columnar-like phenotype in adult mouse oesophageal epithelium and is present in the human condition. These data suggest that induction of HNF4α is a key early step in the formation of Barrett's metaplasia and are consistent with an origin of Barrett's metaplasia from the oesophageal epithelium.


Assuntos
Adenocarcinoma/genética , Esôfago de Barrett/genética , Fator de Transcrição CDX2/genética , Neoplasias Esofágicas/genética , Fator 4 Nuclear de Hepatócito/genética , Adenocarcinoma/patologia , Adulto , Animais , Esôfago de Barrett/patologia , Biópsia , Epitélio/patologia , Neoplasias Esofágicas/patologia , Esôfago/patologia , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Camundongos , Proteínas de Neoplasias/biossíntese , Técnicas de Cultura de Órgãos
6.
J Immunol ; 190(4): 1551-9, 2013 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-23319734

RESUMO

Migration of naive CD4(+) T lymphocytes into lymphoid tissue is essential for their activation and subsequent roles in adaptive immunity. The adhesion molecule L-selectin (CD62L), critical for this process, is highly expressed on naive CD4(+) T lymphocytes and is downregulated upon T lymphocyte activation. We demonstrate protein expression of P2X7R on naive CD4(+) T lymphocytes and show functional channel activity in whole-cell patch clamp recordings. CD62L downregulation occurs rapidly in response to extracellular ATP, a process that is blocked by selective antagonists of P2X7R. This loss of surface CD62L expression was not associated with externalization of phosphatidylserine. While investigating the mechanisms for this process, we revealed that pharmacological modulation of mitochondrial complex I or III, but not inhibition of NADPH oxidase, enhanced P2X7R-dependent CD62L downregulation by increasing ATP potency. Enhanced superoxide generation in the mitochondria of rotenone- and antimycin A-treated cells was observed and may contribute to the enhanced sensitivity of P2X7R to ATP. P2X7R-dependent exposure of phosphatidylserine was also revealed by preincubation with mitochondrial uncouplers prior to ATP treatment. This may present a novel mechanism whereby P2X7R-dependent phosphatidylserine exposure occurs only when cells have enhanced mitochondrial reactive oxygen species generation. The clearance of apoptotic cells may therefore be enhanced by this mechanism which requires functional P2X7R expression.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Diferenciação Celular/imunologia , Regulação para Baixo , Selectina L , Mitocôndrias/metabolismo , Receptores Purinérgicos P2X7/fisiologia , Superóxidos/metabolismo , Regulação para Cima/imunologia , Trifosfato de Adenosina/fisiologia , Apoptose/imunologia , Linfócitos T CD4-Positivos/citologia , Linfócitos T CD4-Positivos/metabolismo , Linhagem Celular Tumoral , Membrana Celular/imunologia , Membrana Celular/metabolismo , Células Cultivadas , Regulação para Baixo/imunologia , Células HEK293 , Humanos , Células Jurkat , Mitocôndrias/imunologia , Superóxidos/farmacologia
7.
Pharmacol Rev ; 64(4): 1027-54, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23023033

RESUMO

The phosphoinositide 3-kinase/mammalian target of rapamycin/protein kinase B (PI3K/mTOR/Akt) signaling pathway is central to a plethora of cellular mechanisms in a wide variety of cells including leukocytes. Perturbation of this signaling cascade is implicated in inflammatory and autoimmune disorders as well as hematological malignancies. Proteins within the PI3K/mTOR/Akt pathway therefore represent attractive targets for therapeutic intervention. There has been a remarkable evolution of PI3K inhibitors in the past 20 years from the early chemical tool compounds to drugs that are showing promise as anticancer agents in clinical trials. The use of animal models and pharmacological tools has expanded our knowledge about the contribution of individual class I PI3K isoforms to immune cell function. In addition, class II and III PI3K isoforms are emerging as nonredundant regulators of immune cell signaling revealing potentially novel targets for disease treatment. Further complexity is added to the PI3K/mTOR/Akt pathway by a number of novel signaling inputs and feedback mechanisms. These can present either caveats or opportunities for novel drug targets. Here, we consider recent advances in 1) our understanding of the contribution of individual PI3K isoforms to immune cell function and their relevance to inflammatory/autoimmune diseases as well as lymphoma and 2) development of small molecules with which to inhibit the PI3K pathway. We also consider whether manipulating other proximal elements of the PI3K signaling cascade (such as class II and III PI3Ks or lipid phosphatases) are likely to be successful in fighting off different immune diseases.


Assuntos
Doenças Autoimunes/enzimologia , Neoplasias Hematológicas/enzimologia , Fosfatidilinositol 3-Quinases/imunologia , Animais , Doenças Autoimunes/tratamento farmacológico , Doenças Autoimunes/imunologia , Inibidores Enzimáticos/farmacologia , Neoplasias Hematológicas/tratamento farmacológico , Neoplasias Hematológicas/imunologia , Humanos , Sistema Imunitário/enzimologia , Inflamação/tratamento farmacológico , Inflamação/enzimologia , Inflamação/imunologia , Fosfatidilinositol 3-Quinases/química , Inibidores de Fosfoinositídeo-3 Quinase , Estrutura Terciária de Proteína , Transdução de Sinais
8.
Eur J Immunol ; 42(12): 3394-404, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22930133

RESUMO

The signalling molecule PI3Kγ has been reported to play a key role in the immune system and the inflammatory response. In particular, it facilitates the migration of haemato-poietic cells to the site of inflammation. In this study, we reveal a novel role for PI3Kγ in the regulation of the pro-inflammatory cytokine IL-17. Loss of PI3Kγ or expression of a catalytically inactive mutant of PI3Kγ in mice led to increased IL-17 production both in vitro and in vivo in response to various stimuli. The kinetic profile was unaltered from WT cells, with no effect on proliferation or other cytokines. Elevated levels of IL-17 were not due to an aberrant expansion of IL-17-producing cells. Furthermore, we also identified an increase in IL-17RA expression on PI3Kγ(-/-) CD4(+) T cells, yet these cells exhibited impaired PI3K-dependent signalling in response to IL-17A, and subsequent NF-κB phosphorylation. In vivo, instillation of recombinant IL-17 into the airways of mice lacking PI3Kγ signalling also resulted in reduced phosphorylation of Akt. Cell influx in response to IL-17 was also reduced in PI3Kγ(-/-) lungs. These data demonstrate PI3Kγ-dependent signalling downstream of IL-17RA, which plays a pivotal role in regulating IL-17 production in T cells.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Interleucina-17/imunologia , Fosfatidilinositol 3-Quinases/imunologia , Receptores de Interleucina-17/imunologia , Transdução de Sinais/imunologia , Animais , Linfócitos T CD4-Positivos/metabolismo , Regulação Enzimológica da Expressão Gênica/genética , Regulação Enzimológica da Expressão Gênica/imunologia , Interleucina-17/genética , Interleucina-17/metabolismo , Pulmão/imunologia , Pulmão/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Fosforilação/genética , Fosforilação/imunologia , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/imunologia , Receptores de Interleucina-17/genética , Receptores de Interleucina-17/metabolismo , Transdução de Sinais/genética
9.
Trends Immunol ; 31(4): 164-9, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20181528

RESUMO

Protein arginine methylation has emerged as a key regulator of signal transduction with an important role in T lymphocyte activation. The predominant methyl transferase PRMT-1 is highly expressed in T helper cells, and ligation of the T cell antigen and costimulatory receptors, induces arginine methylation on several cytoplasmic proteins. Global inhibition of methyl transferases can result in signaling defects in CD4 T cells and profound immunosuppression. Here we suggest that manipulating protein arginine methylation could be a feasible strategy to modulate T lymphocyte function, presenting a novel approach towards immunotherapy and the treatment of T cell-mediated disorders such as autoimmune disease and transplant rejection.


Assuntos
Arginina/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Ativação Linfocitária , Linfócitos T/imunologia , Animais , Humanos , Imunoterapia , Metilação , Transdução de Sinais , Linfócitos T/metabolismo
10.
J Immunol ; 186(8): 4936-45, 2011 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-21402888

RESUMO

SHIP-1 negatively regulates the PI3K pathway in hematopoietic cells and has an emerging role in T lymphocyte biology. PI3K and SHIP can regulate cell migration in leukocytes, particularly in neutrophils, although their role in T cell migration has been less clear. Therefore, we sought to explore the role of SHIP-1 in human CD4(+) T lymphocyte cell migration responses to chemoattractants using a lentiviral-mediated expression system and a short hairpin RNA approach. Silencing of SHIP-1 leads to increased basal phosphorylation of protein kinase B/Akt and its substrate GSK3ß, as well as an increase in basal levels of polymerized actin, suggesting that SHIP-1 might regulate changes in the cytoskeleton. Accordingly, silencing of SHIP-1 led to loss of microvilli and ezrin/radixin/moesin phosphorylation, which could not be rescued by the PI3K inhibitor Ly294002. There were striking morphological changes, including a loss of microvilli projections, which mirrored changes in wild type cells after stimulation with the chemokine CXCL11. There was no defect in directional T cell migration toward CXCL11 in the SHIP-1-silenced cells but, importantly, there was a defect in the overall basal motility of SHIP-1 knockdown cells. Taken together, these results implicate SHIP-1 as a key regulator of basal PI3K signaling in human CD4(+) T lymphocytes with important phosphatase-independent actions, which together are key for maintaining normal morphology and basal motility.


Assuntos
Linfócitos T CD4-Positivos/metabolismo , Movimento Celular , Monoéster Fosfórico Hidrolases/metabolismo , Actinas/metabolismo , Western Blotting , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/ultraestrutura , Sobrevivência Celular , Células Cultivadas , Quimiocina CXCL11/farmacologia , Proteínas do Citoesqueleto/metabolismo , Citoesqueleto/metabolismo , Citometria de Fluxo , Quinase 3 da Glicogênio Sintase/metabolismo , Glicogênio Sintase Quinase 3 beta , Humanos , Inositol Polifosfato 5-Fosfatases , Proteínas de Membrana/metabolismo , Proteínas dos Microfilamentos/metabolismo , Microscopia Eletrônica de Varredura , Microvilosidades/metabolismo , Microvilosidades/ultraestrutura , Fosfatidilinositol 3-Quinases/metabolismo , Fosfatidilinositol-3,4,5-Trifosfato 5-Fosfatases , Fosfatidilinositóis/metabolismo , Monoéster Fosfórico Hidrolases/genética , Fosforilação , Proteínas Proto-Oncogênicas c-akt/metabolismo , Interferência de RNA , Transdução de Sinais
11.
Trends Biochem Sci ; 32(10): 450-6, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17920279

RESUMO

Owing to its widespread activation in inflammation and cancer, a growing appreciation of the therapeutic potential of inhibitors of the phosphoinositide 3-kinase (PI3K) pathway has stimulated intense interest in compounds with suitable pharmacological profiles. These are primarily directed toward PI3K itself. However, as class I PI3Ks are also essential for a range of normal physiological processes, broad spectrum PI3K inhibition could be poorly tolerated. In recent years, patents describing a new generation of PI3K inhibitors have started to appear, with a particular focus on the development of compounds with enhanced isoform selectivity for use as anti-cancer and anti-inflammatory therapies. However, challenges remain for the efforts to pharmacologically target this enzyme family in a successful manner.


Assuntos
Inflamação/tratamento farmacológico , Neoplasias/tratamento farmacológico , Inibidores de Fosfoinositídeo-3 Quinase , Inibidores de Proteínas Quinases/uso terapêutico , Ativação Enzimática , Inflamação/enzimologia , Neoplasias/enzimologia
12.
FEBS Lett ; 596(21): 2721-2735, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36002439

RESUMO

Innate and adaptive immune systems are built-in homeostatic functions of many multicellular organisms and protect the host against foreign pathogens and infections. Dysregulation of the molecular mechanisms of the immune system can result in autoimmune diseases. The immune system can also be harnessed and manipulated to provide targeted cancer therapies, some of them relying on the blockade of immune-checkpoint receptors. Two prominent immune checkpoints, PD-1/PD-L1 and CTLA-4/CD80, comprise receptor-ligand pairs that prevent the host immune cells from attacking host tissues. However, cancer cells upregulate the respective PD-L1 and CD80 ligands for PD-1 and CTLA-4 and thereby evade the host-immune response. Therapeutic drugs that block PD-1/PD-L1 and CTLA-4/CD80 interactions re-enable the immune system to attack cancer cells, but their prognostic biomarker remains challenging. In this review, we discuss how the use of quantitative molecular imaging can be exploited to predict the response to anti-PD-1/PD-L1 therapies and to identify cancer patients who would benefit from them.


Assuntos
Antígeno B7-H1 , Imunoterapia , Neoplasias , Medicina de Precisão , Receptor de Morte Celular Programada 1 , Proteômica , Humanos , Antígeno B7-H1/genética , Antígeno B7-H1/imunologia , Antígeno CTLA-4/genética , Antígeno CTLA-4/imunologia , Imunoterapia/métodos , Neoplasias/tratamento farmacológico , Neoplasias/genética , Neoplasias/imunologia , Medicina de Precisão/métodos , Receptor de Morte Celular Programada 1/genética , Receptor de Morte Celular Programada 1/imunologia , Proteômica/métodos
13.
Cancers (Basel) ; 14(23)2022 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-36497220

RESUMO

BACKGROUND: Cases of the spontaneous regression of multiple pulmonary metastases, after radiofrequency ablation (RFA), of a single lung metastasis, have been documented to be mediated by the immune system. The interaction of immune checkpoints, e.g., PD-1/PD-L1 and CTLA-4/CD80, may explain this phenomenon. The purpose of this study is to identify and quantify immune mechanisms triggered by RFA of pulmonary metastases originating from colorectal cancer. METHODS: We used two-site time-resolved Förster resonance energy transfer as determined by frequency-domain FLIM (iFRET) for the quantification of receptor-ligand interactions. iFRET provides a method by which immune checkpoint interaction states can be quantified in a spatiotemporal manner. The same patient sections were used for assessment of ligand-receptor interaction and intratumoral T-cell labeling. CONCLUSION: The checkpoint interaction states quantified by iFRET did not correlate with ligand expression. We show that immune checkpoint ligand expression as a predictive biomarker may be unsuitable as it does not confirm checkpoint interactions. In pre-RFA-treated metastases, there was a significant and negative correlation between PD-1/PD-L1 interaction state and intratumoral CD3+ and CD8+ density. The negative correlation of CD8+ and interactive states of PD-1/PD-L1 can be used to assess the state of immune suppression in RFA-treated patients.

14.
Biochim Biophys Acta ; 1804(3): 592-7, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19782768

RESUMO

The phosphoinositide 3-kinase signaling pathway regulates a range of T lymphocyte cellular functions including growth, proliferation, cytokine secretion and survival. Aberrant regulation of phosphoinositide 3-kinase-dependent signaling in T lymphocytes has been implicated in inflammatory and autoimmune diseases. In common with much of the immune system, several mechanisms exist to ensure the pathway is tightly regulated to elicit appropriate responses. One level of control involves the Src homology 2 domain-containing inositol-5-phosphatase-1 (SHIP-1) that modulates phosphoinositide 3-kinase signaling by degrading the key signaling lipid PI(3,4,5)P(3) to PI(3,4)P(2), but also serves as a key scaffolding molecule in the formation of multi-protein complexes. Here we discuss the role of SHIP-1 in regulating T lymphocyte and immune function, as well as its potential as a therapeutic target.


Assuntos
Doenças Autoimunes/enzimologia , Proliferação de Células , Monoéster Fosfórico Hidrolases/metabolismo , Linfócitos T/enzimologia , Animais , Doenças Autoimunes/imunologia , Sobrevivência Celular/imunologia , Humanos , Inflamação/enzimologia , Inflamação/imunologia , Inositol Polifosfato 5-Fosfatases , Fosfatidilinositol-3,4,5-Trifosfato 5-Fosfatases , Monoéster Fosfórico Hidrolases/imunologia , Linfócitos T/imunologia , Domínios de Homologia de src/imunologia
15.
Immunology ; 132(4): 503-15, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21255008

RESUMO

The chemokine receptor CXCR3 and its ligands CXCL9, CXCL10 and CXCL11 are involved in variety of inflammatory disorders including multiple sclerosis, rheumatoid arthritis, psoriasis and sarcoidosis. Two alternatively spliced variants of the human CXCR3-A receptor have been described, termed CXCR3-B and CXCR3-alt. Human CXCR3-B binds CXCL9, CXCL10, CXCL11 as well as an additional ligand CXCL4. In contrast, CXCR3-alt only binds CXCL11. We report that CXCL4 induces intracellular calcium mobilization as well as Akt and p44/p42 extracellular signal-regulated kinase phosphorylation, in activated human T lymphocytes. These responses have similar concentration dependence and time-courses to those induced by established CXCR3 agonists. Moreover, phosphorylation of Akt and p44/p42 is inhibited by pertussis toxin, suggesting coupling to Gα(i) protein. Surprisingly, and in contrast with the other CXCR3 agonists, stimulation of T lymphocytes with CXCL4 failed to elicit migratory responses and did not lead to loss of surface CXCR3 expression. Taken together, our findings show that, although CXCL4 is coupled to downstream biochemical machinery, its role in T cells is probably distinct from that of CXCR3-A agonists.


Assuntos
Variação Genética , Receptores CXCR3/genética , Linfócitos T/metabolismo , Acetamidas/farmacologia , Western Blotting , Cálcio/metabolismo , Movimento Celular/efeitos dos fármacos , Células Cultivadas , Quimiocina CXCL10/genética , Quimiocina CXCL10/farmacologia , Quimiocina CXCL11/genética , Quimiocina CXCL11/farmacologia , Quimiocina CXCL9/genética , Quimiocina CXCL9/farmacologia , Relação Dose-Resposta a Droga , MAP Quinases Reguladas por Sinal Extracelular/antagonistas & inibidores , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Expressão Gênica/efeitos dos fármacos , Células HEK293 , Humanos , Toxina Pertussis/farmacologia , Fosforilação/efeitos dos fármacos , Fator Plaquetário 4/genética , Fator Plaquetário 4/farmacologia , Isoformas de Proteínas/agonistas , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-akt/metabolismo , Pirimidinas/farmacologia , Receptores CXCR3/agonistas , Receptores CXCR3/metabolismo , Proteínas Recombinantes/farmacologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Linfócitos T/citologia , Linfócitos T/efeitos dos fármacos
16.
Org Biomol Chem ; 9(22): 7814-21, 2011 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-21952734

RESUMO

Protein arginine N-methyltransferases (PRMTs) selectively replace N-H for N-CH(3) at substrate protein guanidines, a post-translational modification important for a range of biological processes, such as epigenetic regulation, signal transduction and cancer progression. Selective chemical probes are required to establish the dynamic function of individual PRMTs. Herein, model inhibitors designed to occupy PRMT binding sites for an arginine substrate and S-adenosylmethionine (AdoMet) co-factor are described. Expedient access to such compounds by modular synthesis is detailed. Remarkably, biological evaluation revealed some compounds to be potent inhibitors of PRMT1, but inactive against CARM1. Docking studies show how prototype compounds may occupy the binding sites for a co-factor and arginine substrate. Overlay of PRMT1 and CARM1 binding sites suggest a difference in a single amino acid that may be responsible for the observed selectivity.


Assuntos
Arginina/metabolismo , Inibidores Enzimáticos/síntese química , Processamento de Proteína Pós-Traducional , Proteína-Arginina N-Metiltransferases/metabolismo , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Repressoras/metabolismo , S-Adenosilmetionina/metabolismo , Arginina/antagonistas & inibidores , Sítios de Ligação , Cristalografia por Raios X , Inibidores Enzimáticos/farmacologia , Epigênese Genética , Escherichia coli , Humanos , Metilação , Modelos Moleculares , Peso Molecular , Plasmídeos , Ligação Proteica , Proteína-Arginina N-Metiltransferases/antagonistas & inibidores , Proteína-Arginina N-Metiltransferases/química , Proteína-Arginina N-Metiltransferases/genética , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Repressoras/antagonistas & inibidores , Proteínas Repressoras/química , Proteínas Repressoras/genética , S-Adenosilmetionina/antagonistas & inibidores , Especificidade por Substrato , Transformação Bacteriana
17.
Environ Sci Technol ; 45(14): 6188-95, 2011 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-21711052

RESUMO

XAFS spectroscopy has been used to determine the Ni species in particulate matter collected on quartz thimble filters in the stacks of eight residual (No. 6 fuel) oil-burning electric utility steam-generating units. Proper speciation of nickel in emitted particulate matter is necessary to correctly anticipate potential health risks. Analysis of the spectroscopic data using least-squares linear combination methods and a newly developed method specific for small quantities of Ni sulfide compounds in such emissions show that potentially carcinogenic Ni sulfide compounds are absent within the detection limits of the method (≤ 3% of the total Ni) in the particulate matter samples investigated. In addition to the major nickel sulfate phase (NiSO(4)·6H(2)O), lesser amounts of (Ni,Mg)O and/or NiFe(2)O(4) were also identified in most emission samples. On the basis of the results from these emission characterization studies, the appropriateness of the U.S. Environmental Protection Agency's assumption that the Ni compound mixture emitted from residual oil-fired power plants is 50% as carcinogenic as nickel subsulfide (Ni(3)S(2)) should be re-evaluated.


Assuntos
Poluentes Atmosféricos/análise , Cinza de Carvão/química , Monitoramento Ambiental/estatística & dados numéricos , Níquel/análise , Centrais Elétricas , Cinza de Carvão/análise , Análise dos Mínimos Quadrados , Níquel/química , Vapor , Espectroscopia por Absorção de Raios X
18.
J Rheumatol ; 48(6): 867-876, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33132218

RESUMO

OBJECTIVE: The modified Rodnan skin score (mRSS) remains the preferred method for skin assessment in systemic sclerosis (SSc). There are concerns regarding high interobserver variability of mRSS and negative clinical trials utilizing mRSS as the primary endpoint. High-frequency ultrasound (HFUS) allows objective assessment of cutaneous fibrosis in SSc. We investigated the relationship between HFUS with both mRSS and dermal collagen. METHODS: Skin thickness (ST), echogenicity, and novel shear wave elastography (SWE) were assessed in 53 patients with SSc and 15 healthy controls (HCs) at the finger, hand, forearm, and abdomen. The relationship between HFUS parameters with mRSS (n = 53) and dermal collagen (10 patients with SSc and 10 HCs) was investigated. Intraobserver repeatability of HFUS was calculated using intraclass correlation coefficients (ICCs). RESULTS: HFUS assessment of ST (hand/forearm) and SWE (finger/hand) correlated with local mRSS at some sites. Subclinical abnormalities in ST, echogenicity, and SWE were present in clinically uninvolved SSc skin. Additionally, changes in echogenicity and SWE were sometimes apparent despite objectively normal ST on HFUS. ST, SWE, and local mRSS correlated strongly with collagen quantification (r = 0.697, 0.709, 0.649, respectively). Intraobserver repeatability was high for all HFUS parameters (ICCs for ST = 0.946-0.978; echogenicity = 0.648-0.865; and SWE = 0.953-0.973). CONCLUSION: Our data demonstrate excellent reproducibility and reassuring convergent validity with dermal collagen content. Detection of subclinical abnormalities is an additional benefit of HFUS. The observed correlations with collagen quantification support further investigation of HFUS as an alternative to mRSS in clinical trial settings.


Assuntos
Escleroderma Sistêmico , Colágeno , Mãos/diagnóstico por imagem , Humanos , Reprodutibilidade dos Testes , Escleroderma Sistêmico/diagnóstico por imagem , Pele/diagnóstico por imagem , Ultrassonografia
19.
Bioorg Med Chem Lett ; 20(7): 2103-5, 2010 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-20219369

RESUMO

Prototype inhibitors of protein arginine methyltransferases (PRMTs) have been constructed by attaching guanidine functionality via a variable linker to non-reactive amine analogues of the cellular co-factor (S)-adenosyl methionine (AdoMet). Potent inhibition of PRMT1 (IC(50) of approximately 3-6 microM) combined with weak inhibition of the lysine methyltransferase SET7 (approximately 50% of activity at 100 microM) was observed for two such compounds.


Assuntos
Proteína-Arginina N-Metiltransferases/antagonistas & inibidores , Proteína-Arginina N-Metiltransferases/metabolismo , S-Adenosilmetionina/análogos & derivados , S-Adenosilmetionina/farmacologia , Histona-Lisina N-Metiltransferase/antagonistas & inibidores , Histona-Lisina N-Metiltransferase/metabolismo , Humanos , Concentração Inibidora 50 , Metilação , Proteínas Repressoras/antagonistas & inibidores , Proteínas Repressoras/metabolismo , Especificidade por Substrato
20.
Biochem J ; 418(1): 13-27, 2009 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-19159344

RESUMO

T-lymphocyte trafficking is targeted to specific organs by selective molecular interactions depending on their differentiation and functional properties. Specific chemokine receptors have been associated with organ-specific trafficking of memory and effector T-cells, as well as the recirculation of naïve T-cells to secondary lymphoid organs. In addition to the acquisition of tissue-selective integrins and chemokine receptors, an additional level of specificity for T-cell trafficking into the tissue is provided by specific recognition of antigen displayed by the endothelium involving the TCRs (T-cell antigen receptors) and co-stimulatory receptors. Activation of PI3K (phosphoinositide 3-kinase) is a robust signalling event shared by most chemokine receptors as well as the TCR and co-stimulatory receptors, contributing to several aspects of T-lymphocyte homing as well as actin reorganization and other components of the general migratory machinery. Accordingly, inhibition of PI3K has been considered seriously as a potential therapeutic strategy by which to combat various T-lymphocyte-dependent pathologies, including autoimmune and inflammatory diseases, as well as to prevent transplant rejection. However, there is substantial evidence for PI3K-independent mechanisms that facilitate T-lymphocyte migration. In this regard, several other signalling-pathway components, including small GTPases, PLC (phospholipase C) and PKC (protein kinase C) isoforms, have also been implicated in T-lymphocyte migration in response to chemokine stimulation. The present review will therefore examine the PI3K-dependent and -independent signal-transduction pathways involved in T-cell migration during distinct modes of T-cell trafficking in response to either chemokines or the TCR and co-stimulatory molecules.


Assuntos
Antígenos/imunologia , Movimento Celular/imunologia , Quimiocinas/imunologia , Linfócitos T/citologia , Linfócitos T/imunologia , Animais , Humanos , Especificidade de Órgãos/imunologia , Fosfatidilinositol 3-Quinases/classificação , Fosfatidilinositol 3-Quinases/metabolismo
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