RESUMO
Mitapivat, a pyruvate kinase activator, shows great potential as a sickle cell disease (SCD)-modifying therapy. The safety and efficacy of mitapivat as a long-term maintenance therapy are currently being evaluated in two open-label studies. Here we applied a comprehensive multi-omics approach to investigate the impact of activating pyruvate kinase on red blood cells (RBC) from 15 SCD patients. HbSS patients were enrolled in one of the open-label, extended studies (NCT04610866). Leukodepleted RBC obtained from fresh whole blood at baseline, prior to drug initiation, and at longitudinal timepoints over the course of the study were processed for multi-omics through a stepwise extraction of metabolites, lipids and proteins. Mitapivat therapy had significant effects on the metabolome, lipidome and proteome of SCD RBC. Mitapivat decreased 2,3-diphosphoglycerate levels, increased adenosine triphosphate levels, and improved hematologic and sickling parameters in patients with SCD. Agreement between omics measurements and clinical measurements confirmed the specificity of mitapivat on targeting late glycolysis, with glycolytic metabolites ranking as the top correlates to parameters of hemoglobin S oxygen affinity (p50) and sickling kinetics (t50) during treatment. Mitapivat markedly reduced levels of proteins of mitochondrial origin within 2 weeks of initiation of treatment, with minimal changes in reticulocyte counts. In the first 6 months of treatment there were also transient elevations of lysophosphatidylcholines and oxylipins with depletion of free fatty acids, suggestive of an effect on membrane lipid remodeling. Multi-omics analysis of RBC identified benefits for glycolysis, as well as activation of the Lands cycle.
Assuntos
Anemia Falciforme , Eritrócitos , Piruvato Quinase , Adulto , Feminino , Humanos , Masculino , Adulto Jovem , Anemia Falciforme/tratamento farmacológico , Anemia Falciforme/sangue , Ativação Enzimática , Ativadores de Enzimas/uso terapêutico , Ativadores de Enzimas/farmacologia , Eritrócitos/metabolismo , Glicólise/efeitos dos fármacos , Metaboloma , Metabolômica/métodos , Multiômica , Proteoma , Proteômica/métodos , Piruvato Quinase/metabolismo , Resultado do TratamentoRESUMO
Peripheral T-cell lymphoma (PTCL) is a clinically heterogeneous group that represents 10%-15% of all lymphomas. Despite improved genetic and molecular understanding, treatment outcomes for PTCL have not shown significant improvement. Although Janus kinase-2 (JAK2) plays an important role in myeloproliferative neoplasms, the critical role of JAK isoforms in mediating prosurvival signaling in PTCL cells is not well defined. Immunohistochemical analysis of PTCL tumors (n = 96) revealed high levels of constitutively active JAK3 (pJAK3) that significantly (p < 0.04) correlated with the activation state of its canonical substrate STAT3. Furthermore, constitutive activation of JAK3 and STAT3 positively correlated, at least in part, with an oncogenic tyrosine phosphatase PTPN11. Pharmacological inhibition of JAK3 but not JAK1/JAK2 significantly (p < 0.001) decreased PTCL proliferation, survival and STAT3 activation. A sharp contrast was observed in the pJAK3 positivity between ALK+ (85.7%) versus ALK-negative (10.0%) in human PTCL tumors and PTCL cell lines. Moreover, JAK3 and ALK reciprocally interacted in PTCL cells, forming a complex to possibly regulate STAT3 signaling. Finally, combined inhibition of JAK3 (by WHI-P154) and ALK (by crizotinib or alectinib) significantly (p < 0.01) decreased the survival of PTCL cells as compared to either agent alone by inhibiting STAT3 downstream signaling. Collectively, our findings establish that JAK3 is a therapeutic target for a subset of PTCL, and provide rationale for the clinical evaluation of JAK3 inhibitors combined with ALK-targeted therapy in PTCL.
Assuntos
Linfoma de Células T Periférico , Humanos , Linfoma de Células T Periférico/tratamento farmacológico , Linfoma de Células T Periférico/genética , Linhagem Celular Tumoral , Transdução de Sinais , Fosforilação , Receptores Proteína Tirosina Quinases , Janus Quinase 3RESUMO
OBJECTIVES: This study aims to predict the high-grade pattern (HGP) of stage IA lung invasive adenocarcinoma (IAC) based on the high-resolution CT (HRCT) features. METHODS: The clinical, pathological, and HRCT imaging data of 457 patients (from bicentric) with pathologically confirmed stage IA IAC (459 lesions in total) were retrospectively analyzed. The 459 lesions were classified into high-grade pattern (HGP) (n = 101) and non-high-grade pattern (n-HGP) (n = 358) groups depending on the presence of HGP (micropapillary and solid) in pathological results. The clinical and pathological data contained age, gender, smoking history, tumor stage, pathological type, and presence or absence of tumor spread through air spaces (STAS). CT features consisted of lesion location, size, density, shape, spiculation, lobulation, vacuole, air bronchogram, and pleural indentation. The independent predictors for HGP were screened by univariable and multivariable logistic regression analyses. The clinical, CT, and clinical-CT models were constructed according to the multivariable analysis results. RESULTS: The multivariate analysis suggested the independent predictors of HGP, encompassing tumor size (p = 0.001; OR = 1.090, 95% CI 1.035-1.148), density (p < 0.001; OR = 9.454, 95% CI 4.911-18.199), and lobulation (p = 0.002; OR = 2.722, 95% CI 1.438-5.154). The AUC values of clinical, CT, and clinical-CT models for predicting HGP were 0.641 (95% CI 0.583-0.699) (sensitivity = 69.3%, specificity = 79.2%), 0.851 (95% CI 0.806-0.896) (sensitivity = 79.2%, specificity = 79.6%), and 0.852 (95% CI 0.808-0.896) (sensitivity = 74.3%, specificity = 85.8%). CONCLUSION: The logistic regression model based on HRCT features has a good diagnostic performance for the high-grade pattern of stage IA IAC. KEY POINTS: ⢠The AUC values of clinical, CT, and clinical-CT models for predicting high-grade patterns were 0.641 (95% CI 0.583-0.699), 0.851 (95% CI 0.806-0.896), and 0.852 (95% CI 0.808-0.896). ⢠Tumor size, density, and lobulation were independent predictive markers for high-grade patterns. ⢠The logistic regression model based on HRCT features has a good diagnostic performance for the high-grade patterns of invasive adenocarcinoma.
Assuntos
Adenocarcinoma de Pulmão , Adenocarcinoma , Neoplasias Pulmonares , Humanos , Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/patologia , Estudos Retrospectivos , Tomografia Computadorizada por Raios X/métodos , Adenocarcinoma de Pulmão/diagnóstico por imagem , Adenocarcinoma de Pulmão/patologia , Adenocarcinoma/diagnóstico por imagem , Adenocarcinoma/patologia , Pulmão/patologia , Invasividade Neoplásica/patologiaRESUMO
Lymphangioleiomyomatosis (LAM), a rare disease of women, is associated with cystic lung destruction resulting from the proliferation of abnormal smooth muscle-like LAM cells with mutations in the tuberous sclerosis complex (TSC) genes TSC1 and/or TSC2 The mutant genes and encoded proteins are responsible for activation of the mechanistic target of rapamycin (mTOR), which is inhibited by sirolimus (rapamycin), a drug used to treat LAM. Patients who have LAM may also be treated with bronchodilators for asthma-like symptoms due to LAM. We observed stabilization of forced expiratory volume in 1 s over time in patients receiving sirolimus and long-acting beta-agonists with short-acting rescue inhalers compared with patients receiving only sirolimus. Because beta-agonists increase cAMP and PKA activity, we investigated effects of PKA activation on the mTOR pathway. Human skin TSC2+/- fibroblasts or LAM lung cells incubated short-term with isoproterenol (beta-agonist) showed a sirolimus-independent increase in phosphorylation of S6, a downstream effector of the mTOR pathway, and increased cell growth. Cells incubated long-term with isoproterenol, which may lead to beta-adrenergic receptor desensitization, did not show increased S6 phosphorylation. Inhibition of PKA blocked the isoproterenol effect on S6 phosphorylation. Thus, activation of PKA by beta-agonists increased phospho-S6 independent of mTOR, an effect abrogated by beta-agonist-driven receptor desensitization. In agreement, retrospective clinical data from patients with LAM suggested that a combination of bronchodilators in conjunction with sirolimus may be preferable to sirolimus alone for stabilization of pulmonary function.
Assuntos
Agonistas Adrenérgicos beta/farmacologia , Linfangioleiomiomatose/tratamento farmacológico , Linfangioleiomiomatose/metabolismo , Proteínas Supressoras de Tumor/genética , Adulto , Idoso , Broncodilatadores/farmacologia , Domínio Catalítico , Proliferação de Células/efeitos dos fármacos , AMP Cíclico/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Progressão da Doença , Feminino , Fibroblastos/citologia , Fibroblastos/metabolismo , Humanos , Isoproterenol/farmacologia , Pessoa de Meia-Idade , Análise Multivariada , Fosforilação , Testes de Função Respiratória , Estudos Retrospectivos , Transdução de Sinais/efeitos dos fármacos , Sirolimo/farmacologia , Pele/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Proteína 1 do Complexo Esclerose Tuberosa , Proteína 2 do Complexo Esclerose Tuberosa , Proteínas Supressoras de Tumor/metabolismoRESUMO
Dual leucine zipper kinase (DLK, Map3k12) is an axonal protein that governs the balance between degeneration and regeneration through its downstream effectors c-jun N-terminal kinase (JNK) and phosphorylated c-jun (p-c-Jun). In peripheral nerves DLK is generally inactive until induced by injury, after which it transmits signals to the nucleus via retrograde transport. Here we report that in contrast to this mode of regulation, in the uninjured adult mouse cerebellum, DLK constitutively drives nuclear p-c-Jun in cerebellar granule neurons, whereas in the forebrain, DLK is similarly expressed and active, but nuclear p-c-Jun is undetectable. When neurodegeneration results from mutant human tau in the rTg4510 mouse model, p-c-Jun then accumulates in neuronal nuclei in a DLK-dependent manner, and the extent of p-c-Jun correlates with markers of synaptic loss and gliosis. This regional difference in DLK-dependent nuclear p-c-Jun accumulation could relate to differing levels of JNK scaffolding proteins, as the cerebellum preferentially expresses JNK-interacting protein-1 (JIP-1), whereas the forebrain contains more JIP-3 and plenty of SH3 (POSH). To characterize the functional differences between constitutive- versus injury-induced DLK signaling, RNA sequencing was performed after DLK inhibition in the cerebellum and in the non-transgenic and rTg4510 forebrain. In all contexts, DLK inhibition reduced a core set of transcripts that are associated with the JNK pathway. Non-transgenic forebrain showed almost no other transcriptional changes in response to DLK inhibition, whereas the rTg4510 forebrain and the cerebellum exhibited distinct differentially expressed gene signatures. In the cerebellum, but not the rTg4510 forebrain, pathway analysis indicated that DLK regulates insulin growth factor-1 (IGF1) signaling through the transcriptional induction of IGF1 binding protein-5 (IGFBP5), which was confirmed and found to be functionally relevant by measuring signaling through the IGF1 receptor. Together these data illuminate the complex multi-functional nature of DLK signaling in the central nervous system (CNS) and demonstrate its role in homeostasis as well as tau-mediated neurodegeneration.
Assuntos
Encéfalo/metabolismo , Encéfalo/fisiologia , Homeostase/fisiologia , MAP Quinase Quinase Quinases/metabolismo , Estresse Fisiológico/fisiologia , Animais , Axônios/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Sistema de Sinalização das MAP Quinases/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/metabolismo , Neurônios/fisiologia , Transdução de Sinais/fisiologia , Transcriptoma/fisiologiaRESUMO
Multifunctional ß-catenin, with critical roles in both cell-cell adhesion and Wnt-signaling pathways, was among HeLa cell proteins coimmunoprecipitated by antibodies against brefeldin A-inhibited guanine nucleotide-exchange factors 1 and 2 (BIG1 or BIG2) that activate ADP-ribosylation factors (Arfs) by accelerating the replacement of bound GDP with GTP. BIG proteins also contain A-kinase anchoring protein (AKAP) sequences that can act as scaffolds for multimolecular assemblies that facilitate and limit cAMP signaling temporally and spatially. Direct interaction of BIG1 N-terminal sequence with ß-catenin was confirmed using yeast two-hybrid assays and in vitro synthesized proteins. Depletion of BIG1 and/or BIG2 or overexpression of guanine nucleotide-exchange factor inactive mutant, but not wild-type, proteins interfered with ß-catenin trafficking, leading to accumulation at perinuclear Golgi structures. Both phospholipase D activity and vesicular trafficking were required for effects of BIG1 and BIG2 on ß-catenin activation. Levels of PKA-phosphorylated ß-catenin S675 and ß-catenin association with PKA, BIG1, and BIG2 were also diminished after BIG1/BIG2 depletion. Inferring a requirement for BIG1 and/or BIG2 AKAP sequence in PKA modification of ß-catenin and its effect on transcription activation, we confirmed dependence of S675 phosphorylation and transcription coactivator function on BIG2 AKAP-C sequence.
Assuntos
Fatores de Ribosilação do ADP/metabolismo , AMP Cíclico/metabolismo , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Sistemas do Segundo Mensageiro/fisiologia , beta Catenina/metabolismo , Proteínas de Ancoragem à Quinase A/genética , Proteínas de Ancoragem à Quinase A/metabolismo , Fatores de Ribosilação do ADP/genética , AMP Cíclico/genética , Proteínas Quinases Dependentes de AMP Cíclico/genética , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Fatores de Troca do Nucleotídeo Guanina/genética , Guanosina Difosfato/genética , Guanosina Difosfato/metabolismo , Guanosina Trifosfato/genética , Guanosina Trifosfato/metabolismo , Células HeLa , Humanos , Fosfolipase D/genética , Fosfolipase D/metabolismo , Fosforilação/fisiologia , Domínios Proteicos , beta Catenina/genéticaRESUMO
ASAP1 regulates F-actin-based structures and functions, including focal adhesions (FAs) and circular dorsal ruffles (CDRs), cell spreading and migration. ASAP1 function requires its N-terminal BAR domain. We discovered that nonmuscle myosin 2A (NM2A) directly bound the BAR-PH tandem of ASAP1in vitro ASAP1 and NM2A co-immunoprecipitated and colocalized in cells. Knockdown of ASAP1 reduced colocalization of NM2A and F-actin in cells. Knockdown of ASAP1 or NM2A recapitulated each other's effects on FAs, cell migration, cell spreading, and CDRs. The NM2A-interacting BAR domain contributed to ASAP1 control of cell spreading and CDRs. Exogenous expression of NM2A rescued the effect of ASAP1 knockdown on CDRs but ASAP1 did not rescue NM2A knockdown defect in CDRs. Our results support the hypothesis that ASAP1 is a positive regulator of NM2A. Given other binding partners of ASAP1, ASAP1 may directly link signaling and the mechanical machinery of cell migration.
Assuntos
Actomiosina/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Movimento Celular/fisiologia , Miosina não Muscular Tipo IIA/metabolismo , Transdução de Sinais/fisiologia , Actomiosina/genética , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Células HeLa , Humanos , Camundongos , Células NIH 3T3 , Miosina não Muscular Tipo IIA/genética , Ligação Proteica , Estrutura Terciária de ProteínaRESUMO
BACKGROUND: The purpose of our study is to explore the relationship between recovery of neural function and transformation of the internal capsule (IC) after transient middle cerebral artery occlusion (MCAO) by using diffusion kurtosis imaging (DKI). METHODS: Six male adult Sprague-Dawley rats implemented with transient MCAO were used in this study. Sensorimotor function was assessed according to repetitive behavioral testing on day 1, 3, 7, 14, and 28 after cerebral ischemia. Metrics of DKI were acquired, and the time course of the region-to-normal ratio was evaluated in IC. RESULTS: After cerebral ischemia, relative fractional anisotropy in IC decreased on day 3 (P < .01). Relative mean diffusivity (rMD) increased on day 28 (P < .05). Relative mean diffusional kurtosis (rMK) increased on day 3 (P < .01) and decreased on day 7 (P < .05). Relative axial diffusional kurtosis (rKa) increased on day 3 (P < .01) and declined on day 7 (P < .05). Relative radial diffusional kurtosis (rKr) was reduced on day 7 (P < .05). Changes in rMK were larger than changes in rMD on day 3 (P < .05). The factor of rKa and rKr revealed marked difference on day 7 (P < .05) and day 14 (P < .05). Neurological function score showed that rats exhibited functional recovery from day 7 (P < .01) post stroke. CONCLUSIONS: This longitudinal multiparametric magnetic resonance imaging study suggested that K metrics offers information complimentary to conventional diffusion metrics and revealed the procedure during the structural modification in the ipsilateral IC following focal cerebral ischemia. After transient MCAO, the neural transformation occurred in a time-dependent procedure.
Assuntos
Imagem de Difusão por Ressonância Magnética/métodos , Lateralidade Funcional/fisiologia , Infarto da Artéria Cerebral Média/diagnóstico por imagem , Cápsula Interna/diagnóstico por imagem , Análise de Variância , Animais , Anisotropia , Modelos Animais de Doenças , Processamento de Imagem Assistida por Computador , Infarto da Artéria Cerebral Média/complicações , Masculino , Doenças do Sistema Nervoso/diagnóstico por imagem , Doenças do Sistema Nervoso/etiologia , Distribuição Normal , Ratos , Ratos Sprague-Dawley , Fatores de TempoRESUMO
BACKGROUND: The early dysfunction and subsequent recovery after stroke, characterized by the destruction and remodeling of connective pathways between cortex and subcortical regions, is associated with neuroinflammation. As major components of the inflammatory process, reactive astrocytes have double-edged effects on pathological progression. The temporal patterns of astrocyte and neuronal pathway activity can be revealed by systemic and stereotactic manganese-enhanced magnetic resonance imaging (MEMRI), respectively. In the present study, we aimed to detect an association between astrocyte activity and recovery of neuronal connective pathways by combining systemic with stereotactic MEMRI. METHODS: Fifty adult rats, divided into two groups, underwent a 60-min occlusion of the middle cerebral artery. The groups were given either a systemic administration or stereotactic injection of MnCl2 at 1, 3, 7, and 14 days after stroke and underwent MRI 4 and 2 days later, respectively. Immunofluorescence (IF) of group 1 was conducted to corroborate the results. Repetitive behavioral testing was also performed with all rats at 1, 3, 7, and 14 days to obtain a functional score. RESULTS: Ring- or crescent-shaped enhancements formed in the striatal peri-infarct regions (STR) at 11 and 18 days. This was concurrent with the activity of glial fibrillary acidic protein (GFAP)-positive astrocytes, which mainly localized at the peri-infarct region and significantly increased in number at 11 and 18 days after stroke. Microglia/macrophages, detected by IF, mainly localized in the lesion core, rather than in the region of enhancement. The ipsilateral substantia nigra (SN) revealed Mn-related signal enhancement reduction and subsequent signs of the recovery process at 3 to 5 days and 9 to 16 days, respectively. Behavioral testing showed that sensorimotor functions were initially disturbed, but subsequently recovered at 7 and 14 days. CONCLUSIONS: We found a positive temporal correlation between astrogliosis and the recovery of neuronal connective pathways at the chronic stage by using the in vivo method of MEMRI. Our results highlighted the potential contribution of astrocytes to the neuronal recovery of these connective pathways.
Assuntos
Cloretos/farmacologia , Gliose , Infarto da Artéria Cerebral Média/complicações , Imageamento por Ressonância Magnética , Compostos de Manganês/farmacologia , Manganês/farmacocinética , Análise de Variância , Animais , Antígeno CD11b/metabolismo , Cloretos/uso terapêutico , Modelos Animais de Doenças , Proteína Glial Fibrilar Ácida/metabolismo , Gliose/diagnóstico por imagem , Gliose/tratamento farmacológico , Gliose/etiologia , Infarto da Artéria Cerebral Média/diagnóstico por imagem , Masculino , Compostos de Manganês/uso terapêutico , Atividade Motora/efeitos dos fármacos , Fosfopiruvato Hidratase/metabolismo , Ratos , Ratos Sprague-Dawley , Reperfusão , Fatores de TempoRESUMO
Brefeldin A-inhibited guanine nucleotide-exchange factors BIG1 and BIG2 activate, through their Sec7 domains, ADP ribosylation factors (Arfs) by accelerating the replacement of Arf-bound GDP with GTP for initiation of vesicular transport or activation of specific enzymes that modify important phospholipids. They are also implicated in regulation of cell polarization and actin dynamics for directed migration. Reciprocal coimmunoprecipitation of endogenous HeLa cell BIG1 and BIG2 with myosin IIA was demonstrably independent of Arf guanine nucleotide-exchange factor activity, because effects of BIG1 and BIG2 depletion were reversed by overexpression of the cognate BIG molecule C-terminal sequence that follows the Arf activation site. Selective depletion of BIG1 or BIG2 enhanced specific phosphorylation of myosin regulatory light chain (T18/S19) and F-actin content, which impaired cell migration in Transwell assays. Our data are clear evidence of these newly recognized functions for BIG1 and BIG2 in transduction or integration of mechanical signals from integrin adhesions and myosin IIA-dependent actin dynamics. Thus, by anchoring or scaffolding the assembly, organization, and efficient operation of multimolecular myosin phosphatase complexes that include myosin IIA, protein phosphatase 1δ, and myosin phosphatase-targeting subunit 1, BIG1 and BIG2 serve to integrate diverse biophysical and biochemical events in cells.
Assuntos
Movimento Celular/fisiologia , Polaridade Celular/fisiologia , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Fosfatase de Miosina-de-Cadeia-Leve/metabolismo , Miosina não Muscular Tipo IIA/metabolismo , Análise de Variância , Western Blotting , Imunofluorescência , Células HeLa , Humanos , Imunoprecipitação , Fosforilação , RNA Interferente Pequeno/genéticaRESUMO
BACKGROUND: Focal cerebral ischemia results in delayed neurodegeneration in remote brain regions, such as the substantia nigra. To date, a reasonable explanation is still lacking regarding the correlation of magnetic resonance (MR) signal pseudo-normalization following a transient abnormal change and subsequent progressive pathological damage. PURPOSE: To characterize the substantia nigra following middle cerebral artery occlusion and to evaluate the potential pathophysiological changes associated with the pseudo-normalization of MR signals in the substantia nigra at the subacute stage after stroke onset. MATERIAL AND METHODS: Sprague-Dawley rats were subjected to transient middle cerebral artery occlusion. During the occlusion of single middle cerebral artery, computed tomography (CT) perfusion was acquired to observe the blood flow perfusion in the primary ischemic striatum and ipsilateral substantia nigra. Next, the MR T2 relaxation time and apparent diffusion coefficient changes within the substantia nigra were determined on days 1, 3, 7, and 14 after stroke onset, and compared with immunohistochemistry for microglia activation and astrogliosis. RESULTS: Twenty-four rats with strong hypoperfusion in the primary ischemic territory and no alterations of the perfusion in the ipsilateral substantia nigra detected both visually and measurably during the middle cerebral artery occlusion were further studied. All animals showed MR pseudo-normalization with T2 relaxation time and apparent diffusion coefficient recovered in the ipsilateral substantia nigra at the subacute phase following focal cerebral ischemia. Normalization of the MR signals corresponded well with the spatio-temporal occurrence of microglia activation and astrogliosis. CONCLUSION: The pseudo-normalization of T2 relaxation time and apparent diffusion coefficient reflects the neuroinflammatory changes that accompany activation of microglia and astrocytes in the ipsilateral substantia nigra following middle cerebral artery occlusion.
Assuntos
Isquemia Encefálica/patologia , Encefalite/patologia , Imageamento por Ressonância Magnética , Substância Negra/patologia , Animais , Isquemia Encefálica/complicações , Encefalite/complicações , Masculino , Ratos , Ratos Sprague-DawleyRESUMO
OBJECTIVE: Cell-surface localization and intracellular trafficking are essential for the function of ATP-binding cassette transporter A-1 (ABCA1). However, regulation of these activities is still largely unknown. Brefeldin A, an uncompetitive inhibitor of brefeldin A-inhibited guanine nucleotide-exchange proteins (BIGs), disturbs the intracellular distribution of ABCA1, and thus inhibits cholesterol efflux. This study aimed to define the possible roles of BIGs in regulating ABCA1 trafficking and cholesterol efflux, and further to explore the potential mechanism. METHODS AND RESULTS: By vesicle immunoprecipitation, we found that BIG1 was associated with ABCA1 in vesicles preparation from rat liver. BIG1 depletion reduced surface ABCA1 on HepG2 cells, and inhibited by 60% cholesterol release. In contrast, BIG1 overexpression increased surface ABCA1 and cholesterol secretion. With partial restoration of BIG1 through overexpression in BIG1-depleted cells, surface ABCA1 was also restored. Biotinylation and glutathione cleavage revealed that BIG1 small interfering RNA dramatically decreased the internalization and recycling of ABCA1. This novel function of BIG1 was dependent on the guanine nucleotide-exchange activity and achieved through activation of ADP-ribosylation factor 1. CONCLUSIONS: BIG1, through its ability to activate ADP-ribosylation factor 1, regulates cell-surface levels and function of ABCA1, indicating a transcription-independent mechanism for controlling ABCA1 action.
Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Membrana Celular/metabolismo , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Fator 1 de Ribosilação do ADP/metabolismo , Transportador 1 de Cassete de Ligação de ATP , Animais , Apolipoproteína A-I/metabolismo , Biotinilação , Colesterol/metabolismo , Glutationa/metabolismo , Fatores de Troca do Nucleotídeo Guanina/genética , Células HeLa , Células Hep G2 , Humanos , Imunoprecipitação , Lipoproteínas LDL/metabolismo , Fígado/metabolismo , Masculino , Transporte Proteico , Interferência de RNA , Ratos , Ratos Sprague-Dawley , Fatores de Tempo , TransfecçãoRESUMO
BACKGROUND: Being one class of magnetic resonance imaging (MRI) contrast agents, ultrasmall superparamagnetic particles of iron oxides (USPIO) bear the potential to study neuroinflammation following stroke, but there is still debate over whether the iron oxides particles may enter the brain tissue passively over a damaged blood-brain barrier (BBB). PURPOSE: To compare the enhancement patterns of USPIO and gadopentate dimeglumine (Gd-DTPA) during the subacute stage of focal cerebral ischemia, to examine the relationship between USPIO enhancement and BBB disturbance, as well as with neuroinflammatory cell response. MATERIAL AND METHODS: Multiple MR sequences were obtained on days 3 and 6 after transient middle cerebral artery occlusion induced in rats with and without the application of USPIO and Gd-DTPA. The enhancement patterns of the two contrast agents were compared and correlated to histology, including IgG for BBB permeability, Prussian Blue staining for iron particle detection, and CD68 immunohistochemistry staining to identify macrophage/microglia. RESULTS: Gd-DTPA enhancement depicted BBB breakdown being in line with IgG leakage. The USPIO enhanced images demonstrated both diffuse and focal signal alteration in ischemic lesions. The diffuse enhanced pattern had a similar spatial and temporal profile as with Gd-DTPA enhancement. In addition, focal enhanced signal loss was visible on T1-, T2-, and T2*-weighted images, with a peak tendency of MR signal loss, macrophage/microglia concentration and iron particle accumulation at a later phase of the study. CONCLUSION: After focal cerebral ischemia, Gd-DTPA-enhanced MRI showed a higher sensitivity in detecting BBB alterations than did USPIO enhancement. USPIO provided complementary information regarding inflammatory cell activity in neuroinflammatory to cerebral ischemia that had not been visualized using conventional Gd-DTPA. The assessment using multiple MR parameters may identify intracellular and extracellular USPIO in vivo.
Assuntos
Isquemia Encefálica/patologia , Dextranos , Encefalite/patologia , Gadolínio DTPA , Imageamento por Ressonância Magnética/métodos , Nanopartículas de Magnetita , Doença Aguda , Animais , Isquemia Encefálica/complicações , Meios de Contraste , Encefalite/etiologia , Aumento da Imagem/métodos , Masculino , Ratos , Ratos Sprague-Dawley , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
Tumor-associated neutrophils (TANs) have been shown to promote immunosuppression and tumor progression, and a high TAN frequency predicts poor prognosis in triple-negative breast cancer (TNBC). Dysregulation of CREB binding protein (CBP)/P300 function has been observed with multiple cancer types. The bromodomain (BRD) of CBP/P300 has been shown to regulate its activity. In this study, we found that IACS-70654, a novel and selective CBP/P300 BRD inhibitor, reduced TANs and inhibited the growth of neutrophil-enriched TNBC models. In the bone marrow, CBP/P300 BRD inhibition reduced the tumor-driven abnormal differentiation and proliferation of neutrophil progenitors. Inhibition of CBP/P300 BRD also stimulated the immune response by inducing an IFN response and MHCI expression in tumor cells and increasing tumor-infiltrated CTLs. Moreover, IACS-70654 improved the response of a neutrophil-enriched TNBC model to docetaxel and immune checkpoint blockade. This provides a rationale for combining a CBP/P300 BRD inhibitor with standard-of-care therapies in future clinical trials for neutrophil-enriched TNBC.
RESUMO
BACKGROUND AND PURPOSE: Ultrasmall superparamagnetic iron oxide (USPIO) particles to enhance MRI have been used to study neuroinflammation in vivo. Our purpose was to observe the USPIO-enhanced MR signal alterations in the primary ischemic lesion and ipsilateral substantia nigra after middle cerebral artery occlusion (MCAO) to verify the subsequent sequelae of neuroinflammation seen in the primary ischemic focus and secondary degeneration region. MATERIALS AND METHODS: Sprague-Dawley rats were subjected to transient MCAO. In addition to conventional T2-, T1-weighted imaging, USPIO-enhanced MRI was performed in USPIO-injected stroke rats, while Gd-enhanced imaging was acquired in control stroke rats, on days 3, 6 using a 3-T MR scanner. The MR signal characteristics in the primary ischemic striatum, ipsilateral substantia nigra were noted, compared on histopathological H&E, Prussian blue (PB) staining. RESULTS: After MCAO, USPIO-induced T2 hypointensity changes were observed in the primary ischemic region with BBB impairment at both time points. In the substantia nigra ipsilateral to the primary ischemic lesion, there was no evidence of USPIO accumulation detected by MRI and PB staining, and no BBB leakage reflected by Gd-enhanced imaging on days 3 and 6. CONCLUSION: USPIO-enhanced MR signals have variable characteristics in both primary and remote sites after focal cerebral ischemia. This suggests that the neuroinflammatory response to brain ischemia in the primary ischemic focus and secondary degeneration region have different temporal patterns and pathophysiological mechanisms.
Assuntos
Infarto da Artéria Cerebral Média/patologia , Degeneração Neural/patologia , Substância Negra/patologia , Animais , Imageamento por Ressonância Magnética , Masculino , Ratos , Ratos Sprague-DawleyRESUMO
OBJECTIVES: Short-chain acyl-CoA dehydrogenase (SCAD), a key enzyme in the fatty acid oxidation process, is not only involved in ATP synthesis but also regulates the production of mitochondrial reactive oxygen species (ROS) and nitric oxide synthesis. The purpose of this study was to investigate the possible role of SCAD in hypertension-associated vascular remodelling. METHODS: In-vivo experiments were performed on spontaneously hypertensive rats (SHRs, ages of 4âweeks to 20âmonths) and SCAD knockout mice. The aorta sections of hypertensive patients were used for measurement of SCAD expression. In-vitro experiments with t-butylhydroperoxide (tBHP), SCAD siRNA, adenovirus-SCAD (MOI 90) or shear stress (4, 15âdynes/cm 2 ) were performed using human umbilical vein endothelial cells (HUVECs). RESULTS: Compared with age-matched Wistar rats, aortic SCAD expression decreased gradually in SHRs with age. In addition, aerobic exercise training for 8âweeks could significantly increase SCAD expression and enzyme activity in the aortas of SHRs while decreasing vascular remodelling in SHRs. SCAD knockout mice also exhibited aggravated vascular remodelling and cardiovascular dysfunction. Likewise, SCAD expression was also decreased in tBHP-induced endothelial cell apoptosis models and the aortas of hypertensive patients. SCAD siRNA caused HUVEC apoptosis in vitro , whereas adenovirus-mediated SCAD overexpression (Ad-SCAD) protected against HUVEC apoptosis. Furthermore, SCAD expression was decreased in HUVECs exposed to low shear stress (4âdynes/cm 2 ) and increased in HUVECs exposed to 15âdynes/cm 2 compared with those under static conditions. CONCLUSION: SCAD is a negative regulator of vascular remodelling and may represent a novel therapeutic target for vascular remodelling.
Assuntos
Butiril-CoA Desidrogenase , Hipertensão , Ratos , Animais , Camundongos , Humanos , Recém-Nascido , Butiril-CoA Desidrogenase/genética , Butiril-CoA Desidrogenase/metabolismo , Remodelação Vascular , Ratos Endogâmicos SHR , Ratos Wistar , Células Endoteliais da Veia Umbilical Humana/metabolismo , RNA Interferente Pequeno/metabolismo , Camundongos KnockoutRESUMO
Tumor-associated macrophages (TAMs) within the tumor microenvironment (TME) play an important role in tumor growth and progression. TAMs have been involved in producing immunosuppressive TME via various factors; however, the underlying mechanisms remain unclear in B-cell lymphoma, including mantle cell lymphoma (MCL). We identified that chemokine receptor-1 (CCR1) is highly expressed on monocytes (Mo) and macrophages (MΦ), and CCR1 pharmacological inhibition or CCR1 siRNA abolished lymphoma-mediated Mo/MΦ migration in a chemotaxis assay. The deficiency of host CCR1 (CCR1 KO) was associated with decreased infiltration of peritoneal-MΦ compared with WT-CCR1. Functional studies indicated that the genetic depletion of CCR1 or treatment inhibited protumor MΦ (M2-like) phenotype by decreasing CD206 and IL-10 expression. Moreover, CCR1 depletion reprogrammed MΦ toward an MHCII+/TNFα+ immunogenic phenotype. Mechanistically, protumor MΦ driven-IL-10 provides a positive feedback loop to tumor-CCL3 by regulating the CCL3 promoter via STAT1 signaling. Therapeutic in vivo targeting of CCR1 with CCR1 antagonist BX-471 significantly reduced FC-muMCL1 mouse tumors in the syngeneic MCL model by the depletion of M2-TAMs and increased infiltration of cytotoxic CD8+ T cells. Our study established that CCR1 exerts a pivotal role in macrophage programming, thus shaping protumor TME and lymphoma progression. CCR1 inhibition through CCR1 antagonists may be a promising therapeutic strategy to reprogram macrophages in lymphoma-TME and achieve better clinical outcomes in patients.
Assuntos
Neoplasias , Receptores de Quimiocinas , Camundongos , Animais , Receptores de Quimiocinas/metabolismo , Interleucina-10 , Macrófagos/metabolismo , Transdução de Sinais , Neoplasias/metabolismo , Fenótipo , Microambiente TumoralRESUMO
Chemotherapy-induced peripheral neuropathy (CIPN) is a major unmet medical need with limited treatment options. Despite different mechanisms of action, diverse chemotherapeutics can cause CIPN through a converged pathwayâan active axon degeneration program that engages the dual leucine zipper kinase (DLK). DLK is a neuronally enriched kinase upstream in the MAPK-JNK cascade, and while it is dormant under physiological conditions, DLK mediates a core mechanism for neuronal injury response under stress conditions, making it an attractive target for treatment of neuronal injury and neurodegenerative diseases. We have developed potent, selective, brain penetrant DLK inhibitors with excellent PK and activity in mouse models of CIPN. Lead compound IACS-52825 (22) showed strongly effective reversal of mechanical allodynia in a mouse model of CIPN and was advanced into preclinical development.
Assuntos
Antineoplásicos , Doenças do Sistema Nervoso Periférico , Camundongos , Animais , Neurônios , Sistema de Sinalização das MAP Quinases , Encéfalo/metabolismo , Doenças do Sistema Nervoso Periférico/induzido quimicamente , Doenças do Sistema Nervoso Periférico/tratamento farmacológico , Antineoplásicos/efeitos adversos , MAP Quinase Quinase QuinasesRESUMO
Peroxisome proliferator-activated receptor alpha (PPARα) has been implicated in the pathogenesis of cardiac hypertrophy, although its mechanism of action remains largely unknown. To determine the effect of PPARα activation on endothelin-1 (ET-1)-induced cardiomyocyte hypertrophy and explore its molecular mechanisms, we evaluated the interaction of PPARα with nuclear factor of activated T-cells c4 (NFATc4) in nuclei of cardiomyocytes from neonatal rats in primary culture. In ET-1-stimulated cardiomyocytes, data from electrophoretic mobility-shift assays (EMSA) and co-immunoprecipitation (co-IP) revealed that fenofibrate (Fen), a PPARα activator, in a concentration-dependent manner, enhanced the association of NFATc4 with PPARα and decreased its interaction with GATA-4, in promoter complexes involved in activation of the rat brain natriuretic peptide (rBNP) gene. Effects of PPARα overexpression were similar to those of its activation by Fen. PPARα depletion by small interfering RNA abolished inhibitory effects of Fen on NFATc4 binding to GATA-4 and the rBNP DNA. Quantitative RT-PCR and confocal microscopy confirmed inhibitory effects of PPARα activation on elevation of rBNP mRNA levels and ET-1-induced cardiomyocyte hypertrophy. Our results suggest that activated PPARα can compete with GATA-4 binding to NFATc4, thereby decreasing transactivation of NFATc4, and interfering with ET-1 induced cardiomyocyte hypertrophy.
Assuntos
Cardiomegalia/induzido quimicamente , Cardiomegalia/metabolismo , Endotelina-1/farmacologia , Fator de Transcrição GATA4/metabolismo , Miócitos Cardíacos/efeitos dos fármacos , Fatores de Transcrição NFATC/metabolismo , PPAR alfa/metabolismo , Animais , Cardiomegalia/patologia , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Relação Dose-Resposta a Droga , Fenofibrato/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Peptídeo Natriurético Encefálico/genética , Regiões Promotoras Genéticas/efeitos dos fármacos , Ligação Proteica/efeitos dos fármacos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-DawleyRESUMO
A series of pyrimidodiazepines was identified as potent Polo-like kinase 1 (PLK1) inhibitors. The synthesis and SAR are discussed. The lead compound 7 (RO3280) has potent inhibitory activity against PLK1, good selectivity against other kinases, and excellent in vitro cellular potency. It showed strong antitumor activity in xenograft mouse models.