RESUMO
PTPRK is a receptor tyrosine phosphatase that is linked to the regulation of growth factor signalling and tumour suppression. It is stabilized at the plasma membrane by trans homophilic interactions upon cell-cell contact. PTPRK regulates cell-cell adhesion but is also reported to regulate numerous cancer-associated signalling pathways. However, the signalling mechanism of PTPRK remains to be determined. Here, we find that PTPRK regulates cell adhesion signalling, suppresses invasion and promotes collective, directed migration in colorectal cancer cells. In vivo, PTPRK supports recovery from inflammation-induced colitis. In addition, we confirm that PTPRK functions as a tumour suppressor in the mouse colon and in colorectal cancer xenografts. PTPRK regulates growth factor and adhesion signalling, and suppresses epithelial to mesenchymal transition (EMT). Contrary to the prevailing notion that PTPRK directly dephosphorylates EGFR, we find that PTPRK regulation of both EGFR and EMT is independent of its catalytic function. This suggests that additional adaptor and scaffold functions are important features of PTPRK signalling.
Assuntos
Transição Epitelial-Mesenquimal , Humanos , Animais , Camundongos , Receptores ErbB/metabolismo , Receptores ErbB/genética , Transdução de Sinais , Adesão Celular/genética , Movimento Celular , Linhagem Celular Tumoral , Neoplasias Colorretais/patologia , Neoplasias Colorretais/genética , Neoplasias Colorretais/metabolismo , Colite/patologia , Colite/metabolismo , Colite/genética , Colite/induzido quimicamente , Proteínas Tirosina Fosfatases Classe 2 Semelhantes a Receptores/metabolismo , Proteínas Tirosina Fosfatases Classe 2 Semelhantes a Receptores/genética , Intestinos/patologiaRESUMO
Adhesive structures between cells and with the surrounding matrix are essential for the development of multicellular organisms. In addition to providing mechanical integrity, they are key signalling centres providing feedback on the extracellular environment to the cell interior, and vice versa. During development, mitosis and repair, cell adhesions must undergo extensive remodelling. Post-translational modifications of proteins within these complexes serve as switches for activity. Tyrosine phosphorylation is an important modification in cell adhesion that is dynamically regulated by the protein tyrosine phosphatases (PTPs) and protein tyrosine kinases. Several PTPs are implicated in the assembly and maintenance of cell adhesions, however, their signalling functions remain poorly defined. The PTPs can act by directly dephosphorylating adhesive complex components or function as scaffolds. In this review, we will focus on human PTPs and discuss their individual roles in major adhesion complexes, as well as Hippo signalling. We have collated PTP interactome and cell adhesome datasets, which reveal extensive connections between PTPs and cell adhesions that are relatively unexplored. Finally, we reflect on the dysregulation of PTPs and cell adhesions in disease.
Assuntos
Moléculas de Adesão Celular/metabolismo , Adesão Celular , Proteínas Tirosina Fosfatases/metabolismo , Animais , HumanosRESUMO
Lung Transplant recipients are at increased risk of complicated diverticular disease. We aim to assess the rate of diverticular surgery in a postlung transplantation population and identify risk factors for surgery. We performed a retrospective cohort study of lung transplant recipients from 2007 to 2011. Demographic variables were evaluated with the Mann-Whitney U and chi-squared tests. Cox regression was performed to evaluate 1- and 2-year landmark survival, assess predictor variables of diverticular surgery and evaluate impact of surgery on CLAD development. Of 17 of 158 patients (10.7%) underwent diverticular-related surgery. Surgical patients had significantly worse survival than nonsurgical patients at 1 year [aHR 2.93 (1.05-8.21), P = 0.041] and 2 year [aHR 4.17 (1.26-13.84), P = 0.020] landmark analyses. Transplant indication of alpha-1 antitrypsin disease and cystic fibrosis were significantly associated with the need for diverticular surgery. Emergent surgery was associated with poorer survival [aHR 5.12(1.00-26.27), P = 0.050]. Lung transplant patients requiring surgery for complicated diverticular disease have significantly poorer survival than those who do not require surgery. Surgery was more common in patients transplanted for A1AT and CF. Optimal assessment and risk stratification of diverticular disease is necessary to prevent excessive morbidity and mortality following transplantation.
Assuntos
Diverticulite/complicações , Diverticulite/cirurgia , Pneumopatias/complicações , Pneumopatias/cirurgia , Transplante de Pulmão/efeitos adversos , Idoso , Fibrose Cística/complicações , Fibrose Cística/mortalidade , Fibrose Cística/cirurgia , Diverticulite/mortalidade , Feminino , Rejeição de Enxerto , Sobrevivência de Enxerto , Humanos , Terapia de Imunossupressão , Pneumopatias/mortalidade , Masculino , Pessoa de Meia-Idade , Modelos de Riscos Proporcionais , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Resultado do Tratamento , Deficiência de alfa 1-Antitripsina/complicações , Deficiência de alfa 1-Antitripsina/mortalidade , Deficiência de alfa 1-Antitripsina/cirurgiaRESUMO
Comprehensive structure activity relationship (SAR) studies were conducted on a focused screening hit, 2-(methylthio)-3-(phenylsulfonyl)-4H-pyrido[1,2-a]pyrimidin-4-imine (1, IC50: 4.0 nM), as 5-HT6 selective antagonists. Activity was improved some 2-4 fold when small, electron-donating groups were added to the central core as observed in 19, 20 and 26. Molecular docking of key compounds in a homology model of the human 5-HT6 receptor was used to rationalize our structure-activity relationship (SAR) findings. In pharmacokinetic experiments, compound 1 displayed good brain uptake in rats following intra-peritoneal administration, but limited oral bioavailability.
Assuntos
Doença de Alzheimer/tratamento farmacológico , Iminas/farmacocinética , Receptores de Serotonina/uso terapêutico , Animais , Humanos , Iminas/farmacologia , Simulação de Acoplamento Molecular , Ratos , Relação Estrutura-AtividadeRESUMO
Long term outcomes in lung transplant are limited by the development of chronic lung allograft dysfunction (CLAD). Within the past several decades, antibody-mediated rejection (AMR) has been recognized as a risk factor for CLAD. The presence of HLA antibodies in lung transplant candidates, "sensitized patients" may predispose patients to AMR, CLAD, and higher mortality after transplant. This review will discuss issues surrounding the sensitized patient, including mechanisms of sensitization, implications within lung transplant, and management strategies.
Assuntos
Rejeição de Enxerto/imunologia , Antígenos HLA/imunologia , Histocompatibilidade , Isoanticorpos/sangue , Transplante de Pulmão , Tolerância ao Transplante , Rejeição de Enxerto/mortalidade , Rejeição de Enxerto/prevenção & controle , Sobrevivência de Enxerto , Teste de Histocompatibilidade , Humanos , Imunossupressores/uso terapêutico , Transplante de Pulmão/efeitos adversos , Transplante de Pulmão/mortalidade , Medição de Risco , Fatores de Risco , Fatores de Tempo , Tolerância ao Transplante/efeitos dos fármacos , Resultado do TratamentoRESUMO
Magnetic resonance imaging (MRI) is commonly used to evaluate the morphology of the knee in athletes with high-knee impact; however, complex repeated loading of the joint can lead to biochemical and structural degeneration that occurs before visible morphological changes. In this study, we utilized multiparametric quantitative MRI to compare morphology and composition of articular cartilage and subchondral bone shape between young athletes with high-knee impact (basketball players; n = 40) and non-knee impact (swimmers; n = 25). We implemented voxel-based relaxometry to register all cases to a single reference space and performed a localized compositional analysis of T 1ρ - and T 2 -relaxation times on a voxel-by-voxel basis. Additionally, statistical shape modeling was employed to extract differences in subchondral bone shape between the two groups. Evaluation of cartilage composition demonstrated a significant prolongation of relaxation times in the medial femoral and tibial compartments and in the posterolateral femur of basketball players in comparison to relaxation times in the same cartilage compartments of swimmers. The compositional analysis also showed depth-dependent differences with prolongation of the superficial layer in basketball players. For subchondral bone shape, three total modes were found to be significantly different between groups and related to the relative sizes of the tibial plateaus, intercondylar eminences, and the curvature and concavity of the patellar lateral facet. In summary, this study identified several characteristics associated with a high-knee impact which may expand our understanding of local degenerative patterns in this population.
Assuntos
Basquetebol/fisiologia , Cartilagem Articular/fisiologia , Articulação do Joelho/fisiologia , Atletas , Cartilagem Articular/diagnóstico por imagem , Estudos Transversais , Feminino , Humanos , Articulação do Joelho/diagnóstico por imagem , Imageamento por Ressonância Magnética , Masculino , Natação/fisiologia , Adulto JovemRESUMO
The field of lung transplant has made significant advances over the last several decades. Despite these advances, morbidity and mortality remain high when compared with other solid organ transplants. As the field moves forward, the speed by which progress can be made will in part be determined by our ability to overcome several stumbling blocks, including donor shortage, proper selection of candidates, primary graft dysfunction, and chronic lung allograft dysfunction. The advances and developments surrounding these factors will have a significant impact on shaping the field within the coming years. In this review, we look at the current climate (ripe for expanding the donor pool), new technology (ex vivo lung perfusion and bioengineered lungs), cutting-edge innovation (novel biomarkers and new ways to treat infected donors), and evidence-based medicine to discuss current trends and predict future developments for what we hope is a bright future for the field of lung transplantation.
Assuntos
Tecnologia Biomédica/tendências , Pneumopatias/cirurgia , Transplante de Pulmão , Seleção do Doador , Previsões , Rejeição de Enxerto/prevenção & controle , Transplante de Pulmão/efeitos adversos , Transplante de Pulmão/métodos , Transplante de Pulmão/tendências , Disfunção Primária do Enxerto/prevenção & controleRESUMO
Cell-cell communication in multicellular organisms depends on the dynamic and reversible phosphorylation of protein tyrosine residues. The receptor-linked protein tyrosine phosphatases (RPTPs) receive cues from the extracellular environment and are well placed to influence cell signaling. However, the direct events downstream of these receptors have been challenging to resolve. We report here that the homophilic receptor PTPRK is stabilized at cell-cell contacts in epithelial cells. By combining interaction studies, quantitative tyrosine phosphoproteomics, proximity labeling and dephosphorylation assays we identify high confidence PTPRK substrates. PTPRK directly and selectively dephosphorylates at least five substrates, including Afadin, PARD3 and δ-catenin family members, which are all important cell-cell adhesion regulators. In line with this, loss of PTPRK phosphatase activity leads to disrupted cell junctions and increased invasive characteristics. Thus, identifying PTPRK substrates provides insight into its downstream signaling and a potential molecular explanation for its proposed tumor suppressor function.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Cateninas/metabolismo , Adesão Celular , Proteínas de Ciclo Celular/metabolismo , Células Epiteliais/enzimologia , Proteínas dos Microfilamentos/metabolismo , Processamento de Proteína Pós-Traducional , Proteínas Tirosina Fosfatases Classe 2 Semelhantes a Receptores/metabolismo , Linhagem Celular , Células Epiteliais/fisiologia , Humanos , Fosforilação , delta CateninaRESUMO
In solving the P-gp and BCRP transporter-mediated efflux issue in a series of benzofuran-derived pan-genotypic palm site inhibitors of the hepatitis C virus NS5B replicase, it was found that close attention to physicochemical properties was essential. In these compounds, where both molecular weight (MW >579) and TPSA (>110 Å2) were high, attenuation of polar surface area together with weakening of hydrogen bond acceptor strength of the molecule provided a higher intrinsic membrane permeability and more desirable Caco-2 parameters, as demonstrated by trifluoroacetamide 11 and the benchmark N-ethylamino analog 12. In addition, the tendency of these inhibitors to form intramolecular hydrogen bonds potentially contributes favorably to the improved membrane permeability and absorption. The functional group minimization that resolved the efflux problem simultaneously maintained potent inhibitory activity toward a gt-2 HCV replicon due to a switching of the role of substituents in interacting with the Gln414 binding pocket, as observed in gt-2a NS5B/inhibitor complex cocrystal structures, thus increasing the efficiency of the optimization. Noteworthy, a novel intermolecular S=O···C=O n â π* type interaction between the ligand sulfonamide oxygen atom and the carbonyl moiety of the side chain of Gln414 was observed. The insights from these structure-property studies and crystallography information provided a direction for optimization in a campaign to identify second generation pan-genotypic NS5B inhibitors.
RESUMO
As part of a statewide dementia-specific training collaborative, data were collected from nursing assistants and aides who provide paid Alzheimer's care. This study explored the relevance of previous education and practical experiences to specific constructs associated with worker recruitment and retention. Direct-care providers with prior training in gerontology and geriatrics had lower levels of extrinsic job satisfaction and career resilience than those without this kind of continuing education. Program participants who were currently or previously the primary caregiver for a friend or relative with Alzheimer's disease had higher levels of intrinsic job satisfaction but lower levels of career resilience than those with no informal caregiving experience. Current or previous informal caregiving experience may enhance intrinsic job satisfaction by increasing personal commitment to pursue formal care work and providing a kind of inoculation against the demoralization that is too often suffered in these very challenging jobs.
Assuntos
Doença de Alzheimer/enfermagem , Atitude do Pessoal de Saúde , Escolha da Profissão , Satisfação no Emprego , Assistentes de Enfermagem/psicologia , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Assistência ao Paciente/métodos , Inquéritos e QuestionáriosRESUMO
The hepatitis C virus (HCV) NS5B replicase is a prime target for the development of direct-acting antiviral drugs for the treatment of chronic HCV infection. Inspired by the overlay of bound structures of three structurally distinct NS5B palm site allosteric inhibitors, the high-throughput screening hit anthranilic acid 4, the known benzofuran analogue 5, and the benzothiadiazine derivative 6, an optimization process utilizing the simple benzofuran template 7 as a starting point for a fragment growing approach was pursued. A delicate balance of molecular properties achieved via disciplined lipophilicity changes was essential to achieve both high affinity binding and a stringent targeted absorption, distribution, metabolism, and excretion profile. These efforts led to the discovery of BMS-929075 (37), which maintained ligand efficiency relative to early leads, demonstrated efficacy in a triple combination regimen in HCV replicon cells, and exhibited consistently high oral bioavailability and pharmacokinetic parameters across preclinical animal species. The human PK properties from the Phase I clinical studies of 37 were better than anticipated and suggest promising potential for QD administration.
Assuntos
Antivirais/farmacologia , Antivirais/farmacocinética , Benzofuranos/farmacologia , Benzofuranos/farmacocinética , Hepacivirus/efeitos dos fármacos , Hepatite C/tratamento farmacológico , Proteínas não Estruturais Virais/antagonistas & inibidores , Regulação Alostérica/efeitos dos fármacos , Sítio Alostérico/efeitos dos fármacos , Animais , Antivirais/química , Benzofuranos/química , Cães , Descoberta de Drogas , Haplorrinos , Hepatite C/virologia , Humanos , Masculino , Simulação de Acoplamento Molecular , Ratos , Ratos Sprague-Dawley , Proteínas não Estruturais Virais/química , Proteínas não Estruturais Virais/metabolismoRESUMO
The prevailing circuit model predicts that hyperactivity of the striatopallidal pathway and subsequently increased inhibition of external globus pallidus (GPe) neurons lead to the hypokinetic symptoms of Parkinson's disease (PD). It is believed that hyperactivity of the striatopallidal pathway is due to inactivity of dopamine receptors on the somatodendritic membrane of striatopallidal neurons, but the exact cellular underpinnings remain unclear. In this study, we show that mouse GPe astrocytes critically control ambient glutamate level, which in turn gates striatopallidal transmission via the activation of presynaptic metabotropic glutamate receptors. This presynaptic inhibition of striatopallidal transmission is diminished after the chronic loss of dopamine. Elevation of intracellular glutamate content in astrocytes restores the proper regulation of the striatopallidal input in PD models. These findings argue that astrocytes are key regulators of the striatopallidal synapse. Targeting this cell class may serve as an alternative therapeutic strategy for PD.
Assuntos
Globo Pálido/metabolismo , Globo Pálido/fisiopatologia , Receptores de Glutamato Metabotrópico/metabolismo , Transmissão Sináptica , Animais , Astrócitos/metabolismo , Astrócitos/patologia , Corpo Estriado/metabolismo , Corpo Estriado/patologia , Corpo Estriado/fisiopatologia , Dopamina/farmacologia , Globo Pálido/patologia , Ácido Glutâmico/metabolismo , Camundongos Endogâmicos C57BL , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/patologia , Doença de Parkinson , Transdução de Sinais/efeitos dos fármacos , Ácido gama-Aminobutírico/metabolismoRESUMO
The application of parallel synthesis to lead optimization programs in drug discovery has been an ongoing challenge since the first reports of library synthesis. A number of approaches to the application of parallel array synthesis to lead optimization have been attempted over the years, ranging from widespread deployment by (and support of) individual medicinal chemists to centralization as a service by an expert core team. This manuscript describes our experience with the latter approach, which was undertaken as part of a larger initiative to optimize drug discovery. In particular, we highlight how concepts taken from the manufacturing sector can be applied to drug discovery and parallel synthesis to improve the timeliness and thus the impact of arrays on drug discovery.