RESUMO
Zinc is an essential element in living organisms, yet little is known about how cells ensure that zinc is allocated to the correct metalloproteins. Papers in Cell and Cell Reports demonstrate that the ZNG1 family of GTPases have metallochaperone functions: they directly transfer zinc to, and thereby activate, methionine aminopeptidases that are crucial for protein modification during or after translation.
Assuntos
Metaloproteínas , Zinco , Metaloproteínas/metabolismo , Chaperonas Moleculares/metabolismo , Zinco/metabolismoRESUMO
Zinc fluctuations regulate key steps in late oocyte and preimplantation embryo development; however, roles for zinc in preceding stages in early ovarian follicle development, when cooperative interactions exist between the oocyte and somatic cells, are unknown. To understand the roles of zinc during early follicle development, we applied single cell X-ray fluorescence microscopy, a radioactive zinc tracer, and a labile zinc probe to measure zinc in individual mouse oocytes and associated somatic cells within early follicles. Here, we report a significant stage-specific increase and compartmental redistribution in oocyte zinc content upon the initiation of early follicle growth. The increase in zinc correlates with the increased expression of specific zinc transporters, including two that are essential in oocyte maturation. While oocytes in follicles exhibit high tolerance to pronounced changes in zinc availability, somatic survival and proliferation are significantly more sensitive to zinc chelation or supplementation. Finally, transcriptomic, proteomic, and zinc loading analyses reveal enrichment of zinc targets in the ubiquitination pathway. Overall, these results demonstrate that distinct cell type-specific zinc regulations are required for follicle growth and indicate that physiological fluctuation in the localization and availability of this inorganic cofactor has fundamental functions in early gamete development.
Assuntos
Folículo Ovariano , Zinco , Animais , Feminino , Camundongos , Oócitos/metabolismo , Oogênese/fisiologia , Folículo Ovariano/fisiologia , Proteômica , Zinco/metabolismoRESUMO
BACKGROUND: Zinc oxide nanoparticles (ZnONPs) are common materials used in skin-related cosmetics and sunscreen products due to their whitening and strong UV light absorption properties. Although the protective effects of ZnONPs against UV light in intact skin have been well demonstrated, the effects of using ZnONPs on damaged or sunburned skin are still unclear. In this study, we aimed to reveal the detailed underlying mechanisms related to keratinocytes and macrophages exposed to UVB and ZnONPs. RESULTS: We demonstrated that ZnONPs exacerbated mouse skin damage after UVB exposure, followed by increased transepidermal water loss (TEWL) levels, cell death and epithelial thickness. In addition, ZnONPs could penetrate through the damaged epithelium, gain access to the dermis cells, and lead to severe inflammation by activation of M1 macrophage. Mechanistic studies indicated that co-exposure of keratinocytes to UVB and ZnONPs lysosomal impairment and autophagy dysfunction, which increased cell exosome release. However, these exosomes could be taken up by macrophages, which accelerated M1 macrophage polarization. Furthermore, ZnONPs also induced a lasting inflammatory response in M1 macrophages and affected epithelial cell repair by regulating the autophagy-mediated NLRP3 inflammasome and macrophage exosome secretion. CONCLUSIONS: Our findings propose a new concept for ZnONP-induced skin toxicity mechanisms and the safety issue of ZnONPs application on vulnerable skin. The process involved an interplay of lysosomal impairment, autophagy-mediated NLRP3 inflammasome and macrophage exosome secretion. The current finding is valuable for evaluating the effects of ZnONPs for cosmetics applications.
Assuntos
Exossomos , Nanopartículas , Óxido de Zinco , Camundongos , Animais , Óxido de Zinco/toxicidade , Proteína 3 que Contém Domínio de Pirina da Família NLR , Raios Ultravioleta/efeitos adversos , Citocinas , Inflamassomos , Nanopartículas/toxicidade , Células EpiteliaisRESUMO
Phytochemical investigation on the aerial parts of Salvia deserta led to the isolation of eight new pentacyclic triterpenoids including three oleanane- (1 - 3) and five ursane-type (4 - 8) triterpenoids, whose structures were elucidated based on extensive spectroscopic analysis and quantum chemical calculation. Weak immunosuppressive potency was observed for compounds 1, 2, and 4 - 8 via inhibiting the secretion of cytokines TNF-α and IL-6 in LPS-induced macrophages RAW264.7 at 20 µM. In addition, compounds 1, 2, and 4 - 6 exhibited moderate protective activity on t-BHP-induced oxidative injury in HepG2 cells.
Assuntos
Salvia , Triterpenos , Triterpenos/farmacologia , Triterpenos/química , Salvia/química , Estrutura Molecular , Citocinas , Componentes Aéreos da Planta/químicaRESUMO
Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer accounting for 90% of cases. It is a highly invasive and deadly cancer with a gradual onset. Polypyrimidine tract-binding protein 1 (PTBP1) is an important RNA-binding protein involved in RNA metabolism and has been linked to oncogenic splicing events. While the oncogenic role of PTBP1 in HCC cells has been established, the exact mechanism of action remains unclear. This study aimed to investigate the functional connection between PTBP1 and dysregulated splicing events in HCC. Through immunoprecipitation-mass spectrometry analyses, we discovered that the proteins bound to PTBP1 were significantly enriched in the complex responsible for the alternative splicing of FGFR2 (fibroblast growth factor receptor 2). Further RNA immunoprecipitation and quantitative PCR assays confirmed that PTBP1 down-regulated the FGFR2-IIIb isoform levels and up-regulated the FGFR2-IIIc isoform levels in HCC cells, leading to a switch from FGFR2-IIIb to FGFR2-IIIc isoforms. Subsequent functional evaluations using CCK-8, transwell, and plate clone formation assays in HCC cell lines HepG2 and Huh7 demonstrated that FGFR2-IIIb exhibited tumor-suppressive effects, while FGFR2-IIIc displayed tumor-promoting effects. In conclusion, this study provides insights into the PTBP1-mediated alternative splicing mechanism in HCC progression, offering a new theoretical basis for the prevention and treatment of this malignancy. Mechanistically, the isoform switch from FGFR2-IIIb to FGFR2-IIIc promoted epithelial-mesenchymal transformation (EMT) of HCC cells and activated the FGFR cascades ERK and AKT pathways.
Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Humanos , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos/genética , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos/metabolismo , Carcinoma Hepatocelular/genética , Neoplasias Hepáticas/genética , Isoformas de Proteínas/genética , Processamento Alternativo , RNA/metabolismo , Ribonucleoproteínas Nucleares Heterogêneas/genética , Ribonucleoproteínas Nucleares Heterogêneas/metabolismo , Proteína de Ligação a Regiões Ricas em Polipirimidinas/genética , Proteína de Ligação a Regiões Ricas em Polipirimidinas/metabolismoRESUMO
Thymus organogenesis and T cell development are coordinated by various soluble and cell-bound molecules. Heparan sulfate (HS) proteoglycans can interact with and immobilize many soluble mediators, creating fields or gradients of secreted ligands. While the role of HS in the development of many organs has been studied extensively, little is known about its function in the thymus. Here, we examined the distribution of HS in the thymus and the effect of its absence on thymus organogenesis and T cell development. We found that HS was expressed most abundantly on the thymic fibroblasts and at lower levels on endothelial, epithelial, and hematopoietic cells. To study the function of HS in the thymus, we eliminated most of HS in this organ by genetically disrupting the glycosyltransferase Ext1 that is essential for its synthesis. The absence of HS greatly reduced the size of the thymus in fetal thymic organ cultures and in vivo, in mice, and decreased the production of T cells. However, no specific blocks in T cell development were observed. Wild-type thymic fibroblasts were able to physically bind the homeostatic chemokines CCL19, CCL21, and CXCL12 ex vivo. However, this binding was abolished upon HS degradation, disrupting the CCL19/CCL21 chemokine gradients and causing impaired migration of dendritic cells in thymic slices. Thus, our results show that HS plays an essential role in the development and growth of the thymus and in regulating interstitial cell migration.
Assuntos
Heparitina Sulfato/metabolismo , Timo/crescimento & desenvolvimento , Animais , Diferenciação Celular , Movimento Celular , Quimiocina CCL19/metabolismo , Quimiocina CCL21/metabolismo , Proteoglicanas de Heparan Sulfato/metabolismo , Heparitina Sulfato/biossíntese , Camundongos , Camundongos Endogâmicos C57BL , N-Acetilglucosaminiltransferases , Linfócitos T/metabolismo , Timo/efeitos dos fármacosRESUMO
In brief: Proper development of ovarian follicles, comprised of an oocyte and surrounding somatic cells, is essential to support female fertility and endocrine health. Here, we describe a method to isolate single oocytes and somatic cells from the earliest stage follicles, called primordial follicles, and we characterize signals that drive their activation. Abstract: Primordial follicles are the first class of follicles formed in the mammalian ovary and are comprised of an oocyte surrounded by a layer of squamous pre-granulosa cells. This developmental class remains in a non-growing state until individual follicles activate to initiate folliculogenesis. What regulates the timing of follicle activation and the upstream signals that govern these processes are major unanswered questions in ovarian biology. This is partly due to the paucity of data on staged follicle cells since isolating and manipulating individual oocytes and somatic cells from early follicle stages are challenging. To date, most studies on isolated primordial follicles have been conducted on cells collected from animal-age- or oocyte size-specific samples, which encompass multiple follicular stages. Here, we report a method for collecting primordial follicles and their associated oocytes and somatic cells from neonatal murine ovaries using liberase, DNase I, and Accutase. This methodology allows for the identification and collection of follicles immediately post-activation enabling unprecedented interrogation of the primordial-to-primary follicle transition. Molecular profiling by single-cell RNA sequencing revealed that processes including organelle disassembly and cadherin binding were enriched in oocytes and somatic cells as they transitioned from primordial to the primary follicle stage. Furthermore, targets including WNT4, TGFB1, FOXO3, and a network of transcription factors were identified in the transitioning oocytes and somatic cells as potential upstream regulators that collectively may drive follicle activation. Taken together, we have developed a more precise characterization and selection method for studying staged-follicle cells, revealing several novel regulators of early folliculogenesis.
Assuntos
Folículo Ovariano , Transcriptoma , Animais , Feminino , Células da Granulosa , Mamíferos , Camundongos , Oócitos , Ovário/metabolismoRESUMO
BACKGROUND: Zinc oxide nanoparticles (ZnONPs) are widely used nanomaterial in personal cosmetics, such as skin creams and sunscreens, due to their whitening properties and strong UV light absorption. However, the safety issues and the hazards of ZnONPs, which can be taken up by the skin and cause skin toxicity, are still unclear. From a chemoprevention point of view, pterostilbene (PT) has been reported to prevent skin damage effectively by its anti-inflammatory and autophagy inducer effect. This study aims to determine the skin toxicity and the potential mechanisms of UVB and ZnONPs exposure and the preventive effect of PT. RESULTS: The co-exposure of UVB and ZnONPs elicit NLRP3 inflammasome activation and pyroptosis in keratinocytes. Furthermore, exposure to both UVB and ZnONPs also disrupts cellular autophagy, which increases cell exosome release. In vivo UVB and ZnONPs exposure triggers skin toxicity, as indicated by increased histological injury, skin thickness and transepidermal water loss. Notably, the NLRP3 inflammasome-mediated pyroptosis are also activated during exposure. Topical application of pterostilbene attenuates NLRP3 inflammasome activation and pyroptosis by decreasing ROS generation and mitochondrial ROS (mtROS) levels. In addition to its antioxidant effect, PT also reversed autophagy abnormalities by restoring normal autophagic flux and decreasing NLRP3 inflammasome-loaded exosome release. CONCLUSIONS: Our findings reveal that ZnONPs induce skin damage in conjunction with UVB exposure. This process involves an interplay of inflammasomes, pyroptosis, autophagy dysfunction, and exosomes in skin toxicity. PT alleviates skin inflammation by regulating the inflammasome-autophagy-exosome pathway, a finding which could prove valuable when further evaluating ZnONPs effects for cosmetic applications.
Assuntos
Nanopartículas , Óxido de Zinco , Autofagia , Inflamassomos , Proteína 3 que Contém Domínio de Pirina da Família NLR , Piroptose , Óxido de Zinco/toxicidadeRESUMO
This study aimed to assess (1) the reproducibility of three sperm chromatin dispersion (SCD) assays for sperm DNA fragmentation, i.e., LensHooke R10® (R10), Halosperm G2® (G2), and BASO® (BA); (2) the correlation between computer-assisted semen analyzer (CASA) morphokinematic parameters and sperm DNA fragmentation index (DFI), and (3) the diagnostic value for male reproduction by combining semen morphokinematic parameters and DFI. Total 50 male participants were recruited, and all collected semen samples underwent semen analyses and SCD assays. Intra- and inter-observer variability of DFI data from different SCD measures was tested. In addition, the predictive ability of CASA parameters and DFI (with different cutoffs, i.e., 15% and 20%) for infertility was assessed using receiver operating characteristic curve analysis. We found that the G2 and R10 produced satisfactory variance coefficients (5.53%, 5.67%) compared to BA (14.8%). The DFI data from the R10 had lower intra-observer variability, in terms of higher intra-class coefficient (0.9615), than that of the G2 (0.8847) or BA (0.8824). Inter-observer variability of three SCD kits in scoring the DFI was comparable and satisfactory (concordance correlation coefficients ranging 0.9895-0.9630). The CASA parameters (i.e., total motility [r = -0.57], progression motility [r = -0.55], and rapidly progressive motility [r = -0.55]) were significantly correlated with DFI (P < 0.001). The predictive ability of the 15%-cutoff DFI data was better than that of the 20%-cutoff or continuous DFI data. The model comprising the CASA parameters, 15%-cutoff DFI, and 4%-cutoff normal morphology had the highest area under curve (0.8125) for infertility. For SCD assay, the R10 was the most reliable SCD assay to detect sperm DNA fragmentation. Combining the sperm DFI with CASA parameters might be a better diagnostic tool for male reproduction.
Assuntos
Infertilidade , Sêmen , Computadores , Fragmentação do DNA , Fertilidade , Humanos , Masculino , Reprodutibilidade dos Testes , EspermatozoidesRESUMO
Carbon monoxide (CO) has long been known as a "silent killer" because of its ability to bind hemoglobin (Hb), leading to reduced oxygen carrying capacity of Hb, which is the main cause of CO poisoning (COP) in humans. Emerging studies suggest that mitochondria is a key target of CO action that can impact key biological processes, including apoptosis, cellular proliferation, inflammation, and autophagy. Despite its toxicity at high concentrations, CO also exhibits cyto- and tissue-protective effects at low concentrations in animal models of organ injury and disease. Specifically, CO modulates the production of pro- or anti-inflammatory cytokines and mediators by regulating the NLRP3 inflammasome. Given that human diseases are strongly associated with inflammation, a deep understanding of the exact mechanism is helpful for treatment. Autophagic factors and inflammasomes interact in various situations, including inflammatory disease, and exosomes might function as the bridge between the inflammasome and autophagy activation. Thus, the interplay among autophagy, mitochondrial dysfunction, exosomes, and the inflammasome may play pivotal roles in the health effects of CO. In this review, we summarize the latest research on the beneficial and toxic effects of CO and their underlying mechanisms, focusing on the important role of the inflammasome and its possible crosstalk with autophagy and exosomes. This knowledge may lead to the development of new therapies for inflammation-related diseases and is essential for the development of new therapeutic strategies and biomarkers of COP.
Assuntos
Monóxido de Carbono/toxicidade , Inflamassomos/metabolismo , Inflamação/etiologia , Animais , Autofagia/efeitos dos fármacos , Biomarcadores/metabolismo , Intoxicação por Monóxido de Carbono/fisiopatologia , Citocinas/metabolismo , Exossomos/metabolismo , Humanos , Inflamação/patologia , Mitocôndrias/patologiaRESUMO
Silver nanoparticles pose a potential risk to ecosystems and living organisms due to their widespread use in various fields and subsequent gradual release into the environment. Only a few studies have investigated the effects of silver nanoparticles (AgNPs) toxicity on immunological functions. Furthermore, these toxic effects have not been fully explored. Recent studies have indicated that zebrafish are considered a good alternative model for testing toxicity and for evaluating immunological toxicity. Therefore, the purpose of this study was to investigate the toxicity effects of AgNPs on innate immunity using a zebrafish model and to investigate whether the natural compound pterostilbene (PTE) could provide protection against AgNPs-induced immunotoxicity. Wild type and neutrophil- and macrophage-transgenic zebrafish lines were used in the experiments. The results indicated that the exposure to AgNPs induced toxic effects including death, malformation and the innate immune toxicity of zebrafish. In addition, AgNPs affect the number and function of neutrophils and macrophages. The expression of immune-related cytokines and chemokines was also affected. Notably, the addition of PTE could activate immune cells and promote their accumulation in injured areas in zebrafish, thereby reducing the damage caused by AgNPs. In conclusion, AgNPs may induce innate immune toxicity and PTE could ameliorate this toxicity.
Assuntos
Imunidade Inata/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Estilbenos/farmacologia , Animais , Ecossistema , Embrião não Mamífero/efeitos dos fármacos , Neutrófilos/efeitos dos fármacos , Testes de Toxicidade/métodos , Poluentes Químicos da Água/toxicidade , Peixe-ZebraRESUMO
The treatment of pancreatic ductal adenocarcinoma (PDAC) remains a huge challenge, because pro-survival signaling pathways-such as the receptor for advanced glycation end products (RAGE)/signal transducer and activator of transcription 3 (STAT3) pathway-are overexpressed in PDAC cells. Moreover, PDAC cells are highly resistant to chemotherapeutic agents because of autophagy induction. Therefore, autophagy and its modulated signaling pathways are attractive targets for developing novel therapeutic strategies for PDAC. Pterostilbene is a stilbenoid chemically related to resveratrol, and has potential for the treatment of cancers. Accordingly, we investigated whether the autophagy inhibitor chloroquine could potentiate the anticancer effect of pterostilbene in the PDAC cell lines MIA PaCa-2 and BxPC-3, as well as in an orthotopic animal model. The results indicated that pterostilbene combined with chloroquine significantly inhibited autophagy, decreased cell viability, and sensitized the cells to pterostilbene-induced apoptosis via downregulation of the RAGE/STAT3 and protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathways in PDAC cells. The results of the orthotopic animal model showed that pterostilbene combined with chloroquine significantly inhibited pancreatic cancer growth, delayed tumor quadrupling times, and inhibited autophagy and STAT3 in pancreatic tumors. In summary, the present study suggested the novel therapeutic strategy of pterostilbene combined with chloroquine against the growth of pancreatic ductal adenocarcinoma by inhibiting autophagy and downregulating the RAGE/STAT3 signaling pathways.
Assuntos
Antineoplásicos/farmacologia , Autofagia/efeitos dos fármacos , Carcinoma Ductal Pancreático/tratamento farmacológico , Cloroquina/farmacologia , Neoplasias Pancreáticas/tratamento farmacológico , Estilbenos/farmacologia , Antígenos de Neoplasias/metabolismo , Antineoplásicos/química , Carcinoma Ductal Pancreático/metabolismo , Carcinoma Ductal Pancreático/patologia , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Cloroquina/química , Regulação para Baixo/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Proteínas Quinases Ativadas por Mitógeno/antagonistas & inibidores , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patologia , Fator de Transcrição STAT3/antagonistas & inibidores , Fator de Transcrição STAT3/metabolismo , Estilbenos/químicaRESUMO
Cordycepin is an adenosine derivative isolated from Cordyceps sinensis, which has been used as an herbal complementary and alternative medicine with various biological activities. The general anti-cancer mechanisms of cordycepin are regulated by the adenosine A3 receptor, epidermal growth factor receptor (EGFR), mitogen-activated protein kinases (MAPKs), and glycogen synthase kinase (GSK)-3ß, leading to cell cycle arrest or apoptosis. Notably, cordycepin also induces autophagy to trigger cell death, inhibits tumor metastasis, and modulates the immune system. Since the dysregulation of autophagy is associated with cancers and neuron, immune, and kidney diseases, cordycepin is considered an alternative treatment because of the involvement of cordycepin in autophagic signaling. However, the profound mechanism of autophagy induction by cordycepin has never been reviewed in detail. Therefore, in this article, we reviewed the anti-cancer and health-promoting effects of cordycepin in the neurons, kidneys, and the immune system through diverse mechanisms, including autophagy induction. We also suggest that formulation changes for cordycepin could enhance its bioactivity and bioavailability and lower its toxicity for future applications. A comprehensive understanding of the autophagy mechanism would provide novel mechanistic insight into the anti-cancer and health-promoting effects of cordycepin.
Assuntos
Antineoplásicos/farmacologia , Autofagia , Desoxiadenosinas/farmacologia , Saúde , Animais , Autofagia/efeitos dos fármacos , Humanos , Modelos Biológicos , Nanopartículas/químicaRESUMO
Nanotechnology has rapidly promoted the development of a new generation of industrial and commercial products; however, it has also raised some concerns about human health and safety. To evaluate the toxicity of the great diversity of nanomaterials (NMs) in the traditional manner, a tremendous number of safety assessments and a very large number of animals would be required. For this reason, it is necessary to consider the use of alternative testing strategies or methods that reduce, refine, or replace (3Rs) the use of animals for assessing the toxicity of NMs. Autophagy is considered an early indicator of NM interactions with cells and has been recently recognized as an important form of cell death in nanoparticle-induced toxicity. Impairment of autophagy is related to the accelerated pathogenesis of diseases. By using mechanism-based high-throughput screening in vitro, we can predict the NMs that may lead to the generation of disease outcomes in vivo. Thus, a tiered testing strategy is suggested that includes a set of standardized assays in relevant human cell lines followed by critical validation studies carried out in animals or whole organism models such as C. elegans (Caenorhabditis elegans), zebrafish (Danio rerio), and Drosophila (Drosophila melanogaster)for improved screening of NM safety. A thorough understanding of the mechanisms by which NMs perturb biological systems, including autophagy induction, is critical for a more comprehensive elucidation of nanotoxicity. A more profound understanding of toxicity mechanisms will also facilitate the development of prevention and intervention policies against adverse outcomes induced by NMs. The development of a tiered testing strategy for NM hazard assessment not only promotes a more widespread adoption of non-rodent or 3R principles but also makes nanotoxicology testing more ethical, relevant, and cost- and time-efficient.
Assuntos
Autofagia , Nanoestruturas/toxicidade , Testes de Toxicidade/métodos , Animais , Autofagia/efeitos dos fármacos , Ensaios de Triagem em Larga Escala/métodos , HumanosRESUMO
: Cellular senescence is a state of cell cycle arrest characterized by a distinct morphology, gene expression pattern, and secretory phenotype. It can be triggered by multiple mechanisms, including those involved in telomere shortening, the accumulation of DNA damage, epigenetic pathways, and the senescence-associated secretory phenotype (SASP), and so on. In current cancer therapy, cellular senescence has emerged as a potent tumor suppression mechanism that restrains proliferation in cells at risk for malignant transformation. Therefore, compounds that stimulate the growth inhibition effects of senescence while limiting its detrimental effects are believed to have great clinical potential. In this review article, we first review the current knowledge of the pro- and antitumorigeneic functions of senescence and summarize the key roles of telomerase in the regulation of senescence in tumors. Second, we review the current literature regarding the anticancer effects of stilbene compounds that are mediated by the targeting of telomerase and cell senescence. Finally, we provide future perspectives on the clinical utilization of stilbene compounds, especially resveratrol and pterostilbene, as novel cancer therapeutic remedies. We conclude and propose that stilbene compounds may induce senescence and may potentially be used as the therapeutic or adjuvant agents for cancers with high telomerase activity.
Assuntos
Antineoplásicos/uso terapêutico , Senescência Celular/efeitos dos fármacos , Neoplasias/tratamento farmacológico , Estilbenos/uso terapêutico , Telomerase/antagonistas & inibidores , Animais , Antineoplásicos/farmacologia , Humanos , Neoplasias/metabolismo , Neoplasias/patologia , Resveratrol/farmacologia , Resveratrol/uso terapêutico , Estilbenos/farmacologia , Telomerase/metabolismoRESUMO
Prefrontal cortex and striatum are two major areas in the brain. Some research reports suggest that both areas are involved in many advanced cognitive processes, such as learning and memory, reward processing, and behavioral decision. Single-unit recording experiments have found that neurons in the prefrontal cortex and striatum can represent reward information, but it remains elusive whether and how local field potentials (LFPs) in the two areas encode reward information. To investigate these issues, we recorded LFPs simultaneously in the prefrontal cortex and striatum of two monkeys by performing a reward prediction task (a large amount reward vs a small amount reward). Recorded LFP signals were transformed from the time domain to the time and frequency domain using the method of short-time Fourier transform (STFT). We calculated the power in each frequency and time, and examined whether they were different in the two reward conditions. The results showed that power of LFPs in both the prefrontal cortex and striatum distinguished one reward condition from the other one. And the power in small reward trials was greater than that in large reward trials. Furthermore, it was found that the LFPs better encoded reward information in the beta band (14-30 Hz) rather than other frequency bands. Our results suggest that the LFPs in the prefrontal cortex and striatum effectively represent reward information, which would help to further understand functional roles of LFPs in reward processing.
Assuntos
Potenciais de Ação , Corpo Estriado/fisiologia , Córtex Pré-Frontal/fisiologia , Recompensa , Animais , Haplorrinos , Aprendizagem , Memória , NeurôniosRESUMO
Critical vascular inflammation leads to vascular dysfunction and cardiovascular diseases, including abdominal aortic aneurysms, hypertension, and atherosclerosis. Andrographolide is the most active and critical constituent isolated from the leaves of Andrographis paniculata, a herbal medicine widely used for treating anti-inflammation in Asia. In this study, we investigated the mechanisms of the inhibitory effects of andrographolide in vascular smooth muscle cells (VSMCs) exposed to a proinflammatory stimulus, tumor necrosis factor-α (TNF-α). Treating TNF-α-stimulated VSMCs with andrographolide suppressed the expression of inducible nitric oxide synthase in a concentration-dependent manner. A reduction in TNF-α-induced c-Jun N-terminal kinase (JNK), Akt, and p65 phosphorylation was observed in andrographolide-treated VSMCs. However, andrographolide affected neither IκBα degradation nor p38 mitogen-activated protein kinase or extracellular signal-regulated kinase 1/2 phosphorylation under these conditions. Both treatment with LY294002, a phosphatidylinositol 3-kinase/Akt inhibitor, and treatment with SP600125, a JNK inhibitor, markedly reversed the andrographolide-mediated inhibition of p65 phosphorylation. In addition, LY294002 and SP600125 both diminished Akt phosphorylation, whereas LY294002 had no effects on JNK phosphorylation. These results collectively suggest that therapeutic interventions using andrographolide can benefit the treatment of vascular inflammatory diseases, and andrographolide-mediated inhibition of NF-κB activity in TNF-α-stimulated VSMCs occurs through the JNK-Akt-p65 signaling cascade, an IκBα-independent mechanism.
Assuntos
Diterpenos/farmacologia , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Músculo Liso Vascular/metabolismo , Miócitos de Músculo Liso/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos , Fator de Transcrição RelA/metabolismo , Fator de Necrose Tumoral alfa/farmacologia , Animais , Células Cultivadas , Regulação da Expressão Gênica/efeitos dos fármacos , Masculino , Miócitos de Músculo Liso/efeitos dos fármacos , NF-kappa B/antagonistas & inibidores , Óxido Nítrico Sintase Tipo II/genética , Óxido Nítrico Sintase Tipo II/metabolismo , Fosforilação , Proteólise , Ratos , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
BACKGROUND: Aberrant vascular smooth muscle cell (VSMC) proliferation and cerebral endothelial cell (CEC) dysfunction contribute significantly in the pathogenesis of cardiovascular diseases. Therefore, inhibition of these cellular events would be by candidate agents for treating these diseases. In the present study, the mechanism of anti-proliferative and anti-inflammatory effects of andrographolides, a novel nuclear factor-κB inhibitor, was investigated in VSMC and CEC cells. METHODS: VSMCs and CECs were isolated from rat artery and mouse brain, respectively, and cultured before experimentation. The effect of andro on platelet-derived growth factor-BB (PDGF-BB) induced VSMC cell proliferation was evaluated by cell number, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The expression of extracellular signal regulated kinase 1/2 (ERK1/2), proliferating cell nuclear antigen (PCNA), and the effects on lipopolysaccharide (LPS)-induced inducible nitric oxide synthase (iNOS) and, cyclooxygenase-2 (COX2) were detected by Western blotting. RESULTS: Andro significantly inhibited PDGF-BB (10 ng/ml) induced cell proliferation in a concentration (20-100 µM) dependent manner, which may be due to reducing the expression of ERK1/2, and by inhibiting the expression of PCNA. Andro also remarkably diminished LPS-induced iNOS and COX2 expression. CONCLUSIONS: The results of this study suggested that the effects of andro against VSMCs proliferation and CECs dysfunction may represent a promising approach for treatment of vascular diseases. KEY WORDS: Andrographolide; CECs; COX2/iNOS; ERK/PCNA; LPS; PDGF-BB; VSMCs.
RESUMO
BACKGROUND: The mortality rate of liver cancer ranks third in the world, and hepatocellular carcinoma (HCC) is a malignant tumor of the digestive tract. Cucurbitacin B (CuB), a natural compound extracted from Cucurbitaceae spp., is the main active component of Chinese patent medicine the Cucurbitacin Tablet, which has been widely used in the treatment of various malignant tumors in clinics, especially HCC. PURPOSE: This study explored the role and mechanism of CuB in the suppression of liver cancer progression. METHODS: Cell Counting Kit-8 (CCK-8) and colony formation assays were used to detect the inhibitory function of CuB in Huh7, Hep3B, and Hepa1/6 hepatoma cells. Calcein-AM/propidium iodide (PI) staining and lactate dehydrogenase (LDH) measurement assays were performed to determine cell death. Mitochondrial membrane potential (Δψm) was measured, and flow cytometry was performed to evaluate cell apoptosis and cell cycle. Several techniques, such as proteomics, Western blotting (WB), and ribonucleic acid (RNA) interference, were utilized to explore the potential mechanism. The animal experiment was performed to verify the results of in vitro experiments. RESULTS: CuB significantly inhibited the growth of Huh7, Hep3B, and Hepa1/6 cells and triggered the cell cycle arrest in G2/M phage without leading to cell death, especially apoptosis. Knockdown of insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1), a target of CuB, did not reverse CuB elicited cell cycle arrest. CuB enhanced phosphorylated ataxia telangiectasia mutated (p-ATM) and phosphorylated H2A histone family member X (γ-H2AX) levels. Moreover, CuB increased p53 and p21 levels and decreased cyclin-dependent kinase 1 (CDK1) expression, accompanied by improving phosphorylated checkpoint kinase 1 (p-CHK1) level and suppressing cell division cycle 25C (CDC25C) protein level. Interestingly, these phenomena were partly abolished by a deoxyribonucleic acid (DNA) protector methylproamine (MPA). Animal studies showed that CuB also significantly suppressed tumor growth in BALB/c mice bearing Hepa1/6 cells. In tumor tissues, CuB reduced the expression levels of proliferating cell nuclear antigen (PCNA) and γ-H2AX but did not change the terminal deoxynucleotidyl transferase deoxyuridine triphosphate (dUTP) nick-end labeling (TUNEL) level. CONCLUSION: This study demonstrated for the first time that CuB could effectively impede HCC progression by inducing DNA damage-dependent cell cycle arrest without directly triggering cell death, such as necrosis and apoptosis. The effect was achieved through ataxia telangiectasia mutated (ATM)-dependent p53-p21-CDK1 and checkpoint kinase 1 (CHK1)-CDC25C signaling pathways. These findings indicate that CuB may be used as an anti-HCC drug, when the current findings are confirmed by independent studies and after many more clinical phase 1, 2, 3, and 4 testings have been done.
Assuntos
Ataxia Telangiectasia , Carcinoma Hepatocelular , Neoplasias Hepáticas , Triterpenos , Animais , Camundongos , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/metabolismo , Quinase 1 do Ponto de Checagem/genética , Quinase 1 do Ponto de Checagem/metabolismo , Quinase 1 do Ponto de Checagem/uso terapêutico , Proteína Supressora de Tumor p53/metabolismo , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/metabolismo , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Proteínas Mutadas de Ataxia Telangiectasia/uso terapêutico , Pontos de Checagem do Ciclo Celular , Dano ao DNA , Apoptose , Linhagem Celular Tumoral , Proliferação de CélulasRESUMO
Phytochemical investigation on the leaves of Tibetan Leucosceptrum canum, a Chinese medicinal herb, led to the isolation of seven new leucosceptrane sesterterpenoids (1-7) and five known analogs (8-12). Comprehensive spectroscopic analysis (including 1D and 2D NMR, and HRMS), quantum chemistry computations, and single crystal X-ray crystallographic analysis were applied to elucidate their structures. Compounds 1-3 and 6 were the first examples of the leucosceptrane sesterterpenoids with rare C-2 oxidation. Compound 2 exhibited immunosuppressive activities via suppressing the secretion of cytokines IL-6 and TNF-α in LPS-induced macrophages RAW264.7 with IC50 values of 13.39 and 19.34 µM, respectively.