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Pulmonary hypertension (PH) is a chronic progressive vascular disease characterized by abnormal pulmonary vascular resistance and pulmonary artery pressure. The major structural alteration during PH is pulmonary vascular remodelling, which is mainly caused by the imbalance between proliferation and apoptosis of pulmonary vascular cells. Previously, it was thought that apoptosis was the only type of programmed cell death (PCD). Soon afterward, other types of PCD have been identified, including autophagy, pyroptosis, ferroptosis and necroptosis. In this review, we summarize the role of the above five forms of PCD in mediating pulmonary vascular remodelling, and discuss their guiding significance for PH treatment. The current review could provide a better understanding of the correlation between PCD and pulmonary vascular remodelling, contributing to identify new PCD-associated drug targets for PH.
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Apoptosis , Hipertensión Pulmonar , Remodelación Vascular , Humanos , Hipertensión Pulmonar/patología , Hipertensión Pulmonar/fisiopatología , Animales , Necroptosis , Transducción de Señal , Autofagia , Ferroptosis , Arteria Pulmonar/patología , Arteria Pulmonar/metabolismo , PiroptosisRESUMEN
Peripheral serotonin levels are associated with cardiovascular disease risk. We previously found that serum serotonin levels are higher in hyperlipidemic mice than wild-type mice. Evidence also suggests that serotonin regulates biomineralization, in that serotonin treatment augments TNF-a-induced matrix calcification of aortic valve interstitial cells and that a selective inhibitor of peripheral serotonin, LP533401, rescues bone loss induced by ovariectomy in mice. Thus, in the present study, we examined the effects of LP533401 on both skeletal bone mineral density (BMD) and aortic calcification in both young and older hyperlipidemic mice susceptible to calcific atherosclerosis and bone loss. By serial in vivo microCT imaging, we assessed BMD and aortic calcification of Apoe-/- mice fed an atherogenic (high cholesterol) diet alone or mixed with LP533401. Results show that in the young mice, LP533401 blunted skeletal bone loss in lumbar vertebrae but not in femurs. LP533401 also blunted the initial development of aortic calcification but not its progression. Echocardiographic analysis showed that LP533401 blunted both hyperlipidemia-induced cardiac hypertrophy and left ventricular dysfunction. In the older mice, LP533401 increased the BMD of lumbar vertebrae but not of femurs. The aortic calcification progressed in both controls and LP533401-treated mice, but, at post-treatment, LP533401-treated mice had significantly less aortic calcification than the controls. These findings suggest that LP533401 mitigates adverse effects of hyperlipidemia on skeletal and vascular tissues in site- and stage-dependent manners.
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Aterosclerosis , Calcinosis , Hiperlipidemias , Pirimidinas , Calcificación Vascular , Femenino , Ratones , Animales , Serotonina , Calcificación Fisiológica , Válvula Aórtica/diagnóstico por imagen , Hiperlipidemias/complicaciones , Calcificación Vascular/etiologíaRESUMEN
The choice of torque curve in lower-limb enhanced exoskeleton robots is a key problem in the control of lower-limb exoskeleton robots. As a human-machine coupled system, mapping from sensor data to joint torque is complex and non-linear, making it difficult to accurately model using mathematical tools. In this research study, the knee torque data of an exoskeleton robot climbing up stairs were obtained using an optical motion-capture system and three-dimensional force-measuring tables, and the inertial measurement unit (IMU) data of the lower limbs of the exoskeleton robot were simultaneously collected. Nonlinear approximations can be learned using machine learning methods. In this research study, a multivariate network model combining CNN and LSTM was used for nonlinear regression forecasting, and a knee joint torque-control model was obtained. Due to delays in mechanical transmission, communication, and the bottom controller, the actual torque curve will lag behind the theoretical curve. In order to compensate for these delays, different time shifts of the torque curve were carried out in the model-training stage to produce different control models. The above model was applied to a lightweight knee exoskeleton robot. The performance of the exoskeleton robot was evaluated using surface electromyography (sEMG) experiments, and the effects of different time-shifting parameters on the performance were compared. During testing, the sEMG activity of the rectus femoris (RF) decreased by 20.87%, while the sEMG activity of the vastus medialis (VM) increased by 17.45%. The experimental results verify the effectiveness of this control model in assisting knee joints in climbing up stairs.
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Dispositivo Exoesqueleto , Robótica , Humanos , Torque , Extremidad Inferior , Articulación de la RodillaRESUMEN
Triboelectric nanogenerators (TENGs) are of great significance as sustainable power sources that harvest energy from the human body and environment. Nevertheless, due to TENG's impedance-dependent output voltage characteristics, in traditional strategy (TS), real-timely powering a sensor with TENG has a poor sensing on/off ratio (or response), and directly charging a capacitor with TENG shows a low charging efficiency. This degraded real-time powering and charging performance of TENG compared to a commercial constant voltage source is a huge challenge of the TENG field for a long time. This work proposes a synchronous switching strategy (SSS) for TENG to real-timely power sensors or charge capacitors without degrading its performance. Compared with TS, this new strategy enables sensors to have 5-7 times sensing on/off ratio enhancement when using TENG as a power source, reaching the powering ability of a commercial constant voltage source, it makes the powering performance of TENG stable under different driving frequency, improving the powering robustness of TENG. In addition, compared with TS, SSS can also enhance the charging efficiency of TENG in every charging cycle by up to 2.4 times when charging capacitors. This work contributes to real-timely powering or charging the distributed, mobile and wireless electronics using TENG.
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Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, is a complex disorder with an unknown cause. However, the dysbiosis of the gut microbiome has been found to play a role in IBD etiology, including exacerbated immune responses and defective intestinal barrier integrity. The gut microbiome can also be a potential biomarker for several diseases, including IBD. Currently, conventional treatments targeting pro-inflammatory cytokines and pathways in IBD-associated dysbiosis do not yield effective results. Other therapies that directly target the dysbiotic microbiome for effective outcomes are emerging. We review the role of the gut microbiome in health and IBD and its potential as a diagnostic, prognostic, and therapeutic target for IBD. This review also explores emerging therapeutic advancements that target gut microbiome-associated alterations in IBD, such as nanoparticle or encapsulation delivery, fecal microbiota transplantation, nutritional therapies, microbiome/probiotic engineering, phage therapy, mesenchymal stem cells (MSCs), gut proteins, and herbal formulas.
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Inflammatory bowel disease (IBD) is marked by persistent inflammation, and its development and progression are linked to environmental, genetic, immune system and gut microbial factors. DNA methylation (DNAm), as one of the protein modifications, is a crucial epigenetic process used by cells to control gene transcription. DNAm is one of the most common areas that has drawn increasing attention recently, with studies revealing that the interleukin (IL)23/IL12, winglessrelated integration site, IL6associated signal transducer and activator of transcription 3, suppressor of cytokine signaling 3 and apoptosis signaling pathways are involved in DNAm and in the pathogenesis of IBD. It has emerged that DNAmassociated genes are involved in perpetuating the persistent inflammation that characterizes a number of diseases, including IBD, providing a novel therapeutic strategy for exploring their treatment. The present review discusses DNAmassociated genes in the pathogenesis of IBD and summarizes their application as possible diagnostic, prognostic and therapeutic biomarkers in IBD. This may provide a reference for the particular form of IBD and its related methylation genes, aiding in clinical decisionmaking and encouraging therapeutic alternatives.
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Metilación de ADN , Enfermedades Inflamatorias del Intestino , Humanos , Metilación de ADN/genética , Enfermedades Inflamatorias del Intestino/genética , Epigénesis Genética , Animales , Biomarcadores , Transducción de Señal/genéticaRESUMEN
Cardiovascular disease and osteoporosis, major causes of morbidity and mortality, are associated with hyperlipidemia. Recent studies show that empagliflozin (EMPA), an inhibitor of sodium-glucose cotransporter-2 (SGLT2), improves cardiovascular health. In preclinical animal studies, EMPA mitigates vascular calcification in the males but its effects in the females are not known. Thus, we used female mice to test the effects of EMPA on calcification in the artery wall, cardiac function, and skeletal bone. By serial in vivo microCT imaging, we followed the progression of aortic calcification and bone mineral density in young and older female Apoe-/- mice fed a high-fat diet with or without EMPA. The two different age groups were used to compare early vs. advanced stages of aortic calcification. Results show that EMPA treatment increased urine glucose levels. Aortic calcium content increased in both the controls and the EMPA-treated mice, and EMPA did not affect progression of aortic calcium content in both young and older mice. However, 3-D segmentation analysis of aortic calcium deposits on microCT images revealed that EMPA-treated mice had significantly less surface area and volume of calcified deposits as well as fewer numbers of deposits than the control mice. To test for direct effects on vascular cell calcification, we treated murine aortic smooth muscle cells with EMPA, and results showed a slight inhibition of alkaline phosphatase activity and inflammatory matrix calcification. As for skeletal bone, EMPA-treated mice had significantly lower BMD than the controls in both the lumbar vertebrae and femoral bones in both young and older mice. The findings suggest that, in hyperlipidemic female mice, unlike males, SGLT2 inhibition with empagliflozin does not mitigate progression of aortic calcification and may even lower skeletal bone density.
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Compuestos de Bencidrilo , Densidad Ósea , Modelos Animales de Enfermedad , Glucósidos , Hiperlipidemias , Ratones Noqueados para ApoE , Inhibidores del Cotransportador de Sodio-Glucosa 2 , Calcificación Vascular , Microtomografía por Rayos X , Animales , Glucósidos/farmacología , Compuestos de Bencidrilo/farmacología , Femenino , Inhibidores del Cotransportador de Sodio-Glucosa 2/farmacología , Calcificación Vascular/patología , Calcificación Vascular/tratamiento farmacológico , Calcificación Vascular/prevención & control , Calcificación Vascular/metabolismo , Hiperlipidemias/tratamiento farmacológico , Densidad Ósea/efectos de los fármacos , Aorta/efectos de los fármacos , Aorta/patología , Aorta/metabolismo , Aorta/diagnóstico por imagen , Aorta/fisiopatología , Enfermedades de la Aorta/patología , Enfermedades de la Aorta/metabolismo , Enfermedades de la Aorta/prevención & control , Enfermedades de la Aorta/tratamiento farmacológico , Enfermedades de la Aorta/fisiopatología , Enfermedades de la Aorta/diagnóstico por imagen , Ratones Endogámicos C57BL , Dieta Alta en Grasa , Ratones , Factores de Edad , Células CultivadasRESUMEN
Background: B cell lymphoma 6 (BCL6) is an important transcription factor of T follicular helper (Tfh) cells, which regulate the humoral response by supporting the maturation of germinal center B cells and plasma cells. The aim of this study is to investigate the expansion of T follicular helper cells and the effect of the BCL6 inhibitor FX1 in acute and chronic cardiac transplant rejection models. Methods: A mouse model of acute and chronic cardiac transplant rejection was established. Splenocytes were collected at different time points after transplantation for CXCR5+PD-1+ and CXCR5+BCL6+ Tfh cells detection by flow cytometry (FCM). Next, we treated the cardiac transplant with BCL6 inhibitor FX1 and the survival of grafts was recorded. The hematoxylin and eosin, Elastica van Gieson, and Masson staining of cardiac grafts was performed for the pathological analysis. Furthermore, the proportion and number of CD4+ T cells, effector CD4+ T cells (CD44+CD62L-), proliferating CD4+ T cells (Ki67+), and Tfh cells in the spleen were detected by FCM. The cells related to humoral response (plasma cells, germinal center B cells, IgG1+ B cells) and donor-specific antibody were also detected. Results: We found that the Tfh cells were significantly increased in the recipient mice on day 14 post transplantation. During the acute cardiac transplant rejection, even the BCL6 inhibitor FX1 did not prolong the survival or attenuate the immune response of cardiac graft, the expansion of Tfh cell expansion inhibit. During the chronic cardiac transplant rejection, FX1 prolonged survival of cardiac graft, and prevented occlusion and fibrosis of vascular in cardiac grafts. FX1 also decreased the proportion and number of splenic CD4+ T cells, effector CD4+ T cells, proliferating CD4+ T cells, and Tfh cells in mice with chronic rejection. Moreover, FX1 also inhibited the proportion and number of splenic plasma cells, germinal center B cells, IgG1+ B cells, and the donor-specific antibody in recipient mice. Conclusion: We found BCL6 inhibitor FX1 protects chronic cardiac transplant rejection and inhibits the expansion of Tfh cells and the humoral response, which suggest that BCL6 is a potential therapeutic target of the treatment for chronic cardiac transplant rejection.
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Inflammatory bowel disease (IBD) has been referred to as the "green cancer," and its progression to colorectal cancer (CRC) poses a significant challenge for the medical community. A common factor in their development is glycolysis, a crucial metabolic mechanism of living organisms, which is also involved in other diseases. In IBD, glycolysis affects gastrointestinal components such as the intestinal microbiota, mucosal barrier function, and the immune system, including macrophages, dendritic cells, T cells, and neutrophils, while in CRC, it is linked to various pathways, such as phosphatidylinositol-3-kinase (PI3K)/AKT, AMP-activated protein kinase (AMPK), mammalian target of rapamycin (mTOR), and transcription factors such as p53, Hypoxia-inducible factor (HIF), and c-Myc. Thus, a comprehensive study of glycolysis is essential for a better understanding of the pathogenesis and therapeutic targets of both IBD and CRC. This paper reviews the role of glycolysis in diseases, particularly IBD and CRC, via its effects on the intestinal microbiota, immunity, barrier integrity, signaling pathways, transcription factors and some therapeutic strategies targeting glycolytic enzymes.
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Neoplasias Colorrectales , Enfermedades Inflamatorias del Intestino , Humanos , Transducción de Señal , Neoplasias Colorrectales/etiología , Factores de Transcripción , GlucólisisRESUMEN
BACKGROUND AND AIMS: Cardiovascular disease risk is associated with coronary artery calcification and is mitigated by regular exercise. Paradoxically, elite endurance athletes, who have low risk, are likely to have more coronary calcification, raising questions about the optimal level of activity. METHODS: Female hyperlipidemic (Apoe-/-) mice with baseline aortic calcification were subjected to high-speed (18.5 m/min), low-speed (12.5 m/min), or no treadmill exercise for 9 weeks. 18F-NaF microPET/CT images were acquired at weeks 0 and 9, and echocardiography was performed at week 9. RESULTS: In controls, aortic calcium content and density increased significantly. Exercise regimens did not alter the time-dependent increase in content, but the increase in mean density was blunted. Interestingly, the low-speed regimen significantly reduced 18F-NaF uptake, a marker of surface area. Left ventricular (LV) systolic function was lower while LV diameter was greater in the low-speed group compared with controls or the high-speed group. In the low-speed group, vertebral bone density by CT decreased significantly, contrary to expectations. Male hyperlipidemic (Apoe-/-) mice were fed a Western diet and also subjected to low-speed or no exercise followed by imaging at weeks 0 and 9. In males, exercise also did not alter the time-dependent increase in aortic calcification. Exercise did not affect 18F-NaF uptake or bone mineral density, but it blunted the diet-induced LV hypertrophy seen in controls. CONCLUSIONS: These results suggest that, in mice, exercise has differential effects on aortic calcification, cardiac function, and skeletal bone mineral density.
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Calcinosis , Enfermedad de la Arteria Coronaria , Masculino , Femenino , Ratones , Animales , Aorta , EcocardiografíaRESUMEN
As a typical inflammatory bowel disease (IBD), ulcerative colitis (UC) has become prevalent worldwide in recent years. Though several materials have been proved to be effective in reducing intestinal oxidative stress to alleviate UC symptoms, dependence on high doses of exogenous drugs amplifies their safety risk for patients. To address this challenge, an oral therapy based on colon-targeting delivery of low-dose rhamnolipid (RL)/fullerene (C60) nanocomposites has been reported. With high biocompatibility being verified, RL/C60 largely mitigated the inflammation of mice with colitis shortly after its oral administration. Not only this, but also the intestinal microbiome of diseased mice was remarkably restored to the near-healthy level by our composites. Specifically, RL/C60 significantly promoted the colonization of intestinal probiotics and suppressed the biofilm formation of pathogenic bacteria, which is beneficial for reshaping the intestinal barrier. A close relationship of cytokines and oxidoreductases levels with gut flora further revealed that a change in RL/C60-induced intestinal microecology effectively improved the organismal immune system, which can be considered important for long-time recovery from UC.
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Colitis Ulcerosa , Fulerenos , Microbioma Gastrointestinal , Nanocompuestos , Ratones , Animales , Colitis Ulcerosa/inducido químicamente , Colitis Ulcerosa/tratamiento farmacológico , Fulerenos/farmacología , Estrés OxidativoRESUMEN
ETHNOPHARMACOLOGICAL RELEVANCE: Pulmonary fibrosis (PF) is a pathological process of irreversible scarring of lung tissues, with limited treatment means. Sceptridium ternatum (Thunb.) Lyon (STE) is a traditional Chinese herbal medicine that has a traditional use in relieving cough and asthma, resolving phlegm, clearing heat, and detoxicating in China. However, its role in PF has not been reported. AIM OF THE STUDY: This study aims to investigate the protective role of STE in PF and the underlying mechanisms. MATERIALS AND METHODS: Sprague-Dawley (SD) rats were divided into control group, PF model group, positive drug (pirfenidone) group and STE group. After 28 days of STE administration in bleomycin (BLM)-induced PF rats, living Nuclear Magnetic Resonance Imaging (NMRI) was used to observe the structural changes of lung tissues. H&E and Masson's trichrome staining were used to observe PF-associated pathological alteration, and immunohistochemistry (IHC) staining, western blotting, and qRT-PCR were used to detect the expression of PF-related marker proteins in the lung tissues. ELISA was used to detect PF-associated biochemical criteria in the lung tissue homogenates. The proteomics technology was used to screen the different proteins. Co-immunoprecipitation, western blotting, and IHC staining were used to confirm the underlying targets of STE as well as its downstream signaling. UPLC-Triple-TOF/MS assay was used to explore the effective components in the alcohol extracts of STE. Autodock vina was used to detect the potential binding between the above effective components and SETDB1. RESULTS: STE prevented PF by inhibiting the activation of lung fibroblasts and ECM deposition in BLM-induced PF rats. Mechanism analyses demonstrated that STE could inhibit the up-regulation of SETDB1 induced by BLM and TGF-ß1, which further blocked the binding of SETDB1 and STAT3 as well as the phosphorylation of STAT3, ultimately preventing the activation and proliferation of lung fibroblasts. CONCLUSION: STE played a preventive role in PF by targeting the SETBD1/STAT3/p-STAT3 pathway, which may be a potential therapeutic agent for PF.
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Medicamentos Herbarios Chinos , Fibrosis Pulmonar , Ratas , Animales , Ratas Sprague-Dawley , Fibrosis Pulmonar/inducido químicamente , Fibrosis Pulmonar/tratamiento farmacológico , Fibrosis Pulmonar/metabolismo , Pulmón , Bleomicina , Medicamentos Herbarios Chinos/efectos adversos , Etanol/farmacologíaRESUMEN
Although it is an essential nutrient, high choline intake directly or indirectly via its metabolite is associated with increased risk of cardiovascular disease, the mechanism of which remains to be elucidated. The present study was performed to investigate whether hydrogen sulfide (H2S) was involved in high choline-induced cardiac dysfunction and explore the potential mechanisms. We found that ejection fraction (EF) and fractional shortening (FS), the indicators of cardiac function measured by echocardiography, were significantly decreased in mice fed a diet containing 1.3% choline for 4 months as compared to the control, while applying 3,3-dimethyl-1-butanol (DMB) to suppress trimethylamine N-oxide (TMAO, a metabolite of choline) generation ameliorated the cardiac function. Subsequently, we found that feeding choline or TMAO significantly increased the protein levels of cyclic GMP-AMP (cGAMP) synthase (cGAS), stimulator of interferon genes (STING), NOD-like receptor protein 3 (NLRP3), caspase-1, and interleukin-1ß (IL-1ß) as compared to the control, which indicated the activation of cGAS-STING-NLRP3 inflammasome axis. Moreover, the protein expression of cystathionine γ-lyase (CSE), the main enzyme for H2S production in the cardiovascular system, was significantly increased after dietary supplementation with choline, but the plasma H2S levels were significantly decreased. To observe the effect of endogenous H2S, CSE knockout (KO) mice were used, and we found that the EF, FS, and plasma H2S levels in WT mice were significantly decreased after dietary supplementation with choline, while there was no difference between CSE KO + control and CSE KO + choline group. To observe the effect of exogenous H2S, mice were intraperitoneally injected with sodium hydrosulfide (NaHS, a H2S donor) for 4 months, and we found that NaHS improved the cardiac function and reduced the protein levels of cGAS, STING, NLRP3, caspase-1, and IL-1ß in mice receiving dietary choline. In conclusion, our studies revealed that high choline diet decreased plasma H2S levels and induced cardiac dysfunction via cGAS-STING-NLRP3 inflammasome axis while H2S treatment could restore the cardiac function by inhibiting cGAS-STING-NLRP3 inflammasome axis.
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Cardiopatías , Sulfuro de Hidrógeno , Animales , Caspasa 1/metabolismo , Colina/toxicidad , Cistationina gamma-Liasa/metabolismo , Cardiopatías/inducido químicamente , Sulfuro de Hidrógeno/metabolismo , Sulfuro de Hidrógeno/farmacología , Sulfuro de Hidrógeno/uso terapéutico , Inflamasomas/metabolismo , Proteínas de la Membrana/metabolismo , Ratones , Ratones Noqueados , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Proteínas NLR , NucleotidiltransferasasRESUMEN
Wnt11 plays an essential role in gastrointestinal epithelial proliferation, and previous investigations have focused on development and immune responses. However, the roles of how enteric bacteria regulate Wnt11 and how Wnt11 modulates the host response to pathogenic bacteria remain unexplored. This study investigated the effects of Salmonella infection on Wnt activation in intestinal epithelial cells. We found that Wnt11 mRNA and protein expression were elevated after Salmonella colonization. Wnt11 protein secretion in epithelial cells was also elevated after bacterial infection. Furthermore, we demonstrated that pathogenic Salmonella regulated Wnt11 expression and localization in vivo. We found a decrease in Salmonella invasion in cells with Wnt11 overexpression compared with cells with normal Wnt11 level. IL-8 mRNA in Wnt11-transfected cells was low; however, it was enhanced in cells with a low level of Wnt11 expression. Functionally, Wnt11 overexpression inhibited Salmonella-induced apoptosis. AvrA is a known bacterial effector protein that stabilizes ß-catenin, the downstream regulator of Wnt signaling, and inhibits bacterially induced intestinal inflammation. We observed that Wnt11 expression, secretion, and transcriptional activity were regulated by Salmonella AvrA. Overall, Wnt11 is involved in the protection of the host intestinal cells by blocking the invasion of pathogenic bacteria, suppressing inflammation, and inhibiting apoptosis. Wnt11 is a novel and important contributor to intestinal homeostasis and host defense.
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Colon/inmunología , Infecciones por Salmonella/inmunología , Salmonella typhimurium/inmunología , Proteínas Wnt/inmunología , Animales , Apoptosis/inmunología , Proteínas Bacterianas/genética , Proteínas Bacterianas/inmunología , Células CACO-2 , Colon/citología , Colon/microbiología , Modelos Animales de Enfermedad , Células Epiteliales/citología , Células Epiteliales/inmunología , Células Epiteliales/microbiología , Femenino , Expresión Génica/inmunología , Células HT29 , Humanos , Ratones , Ratones Endogámicos C57BL , Infecciones por Salmonella/patología , Salmonella typhimurium/genética , Salmonella typhimurium/crecimiento & desarrollo , Transducción de Señal/inmunología , Regulación hacia Arriba/inmunología , Proteínas Wnt/genética , beta Catenina/metabolismoRESUMEN
Methylation, first proposed in DNAs, but later found in RNAs, serves as one of the most widespread epigenetic modifications in eukaryotes, where N6-methyladenosine (m6A) modification has been found to play an important role in a variety of cancers including colorectal cancer (CRC). Under the action of various enzymes and proteins, the regulatory role of m6A in RNAs and immune cells has also been gradually realized. This paper reviews the general biogenesis and effects of m6A, and its emerging crucial role in intestinal mucosal immunity via the regulation of RNAs and immune cells, and thus closely related to the occurrence and development of inflammatory bowel disease (IBD) and CRC. m6A-related genes and regulatory factors are expected to be potential predictive markers and therapeutic targets.
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During cancer metastasis, circulating tumor cells constantly experience hemodynamic shear stress in the circulation. Cellular responses to shear stress including cell viability and proliferation thus play critical roles in cancer metastasis. Here, we developed a microfluidic approach to establish a circulatory microenvironment and studied circulating human colon cancer HCT116 cells in response to a variety of magnitude of shear stress and circulating time. Our results showed that cell viability decreased with the increase of circulating time, but increased with the magnitude of wall shear stress. Proliferation of cells survived from circulation could be maintained when physiologically relevant wall shear stresses were applied. High wall shear stress (60.5 dyne/cm(2)), however, led to decreased cell proliferation at long circulating time (1 h). We further showed that the expression levels of ß-catenin and c-myc, proliferation regulators, were significantly enhanced by increasing wall shear stress. The presented study provides a new insight to the roles of circulatory shear stress in cellular responses of circulating tumor cells in a physiologically relevant model, and thus will be of interest for the study of cancer cell mechanosensing and cancer metastasis.
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Proliferación Celular/genética , Mecanotransducción Celular , Técnicas Analíticas Microfluídicas/instrumentación , Células Neoplásicas Circulantes/patología , Fenómenos Biomecánicos , Supervivencia Celular , Expresión Génica , Células HCT116 , Humanos , Modelos Biológicos , Células Neoplásicas Circulantes/metabolismo , Proteínas Proto-Oncogénicas c-myc/genética , Proteínas Proto-Oncogénicas c-myc/metabolismo , Reología , Estrés Mecánico , beta Catenina/genética , beta Catenina/metabolismoRESUMEN
The tissue inhibitor of metalloproteinase (TIMP) family, including TIMP-2, regulates the activity of multifunctional metalloproteinases in pathogenesis of melanoma. The Wnt/ß-catenin pathway is constitutively activated and plays a critical role in melanoma progression. However, the relationship between TIMP-2 expression and ß-catenin activity is still unclear. We hypothesize that TIMP-2 over expression inhibits the activation of the Wnt/ß-catenin pathway in melanoma cells. Protein expression, distribution, and transcriptional activity of ß-catenin were assayed in established stable melanoma cell lines: parental A2058 expressing, A2058 T2-1 over-expressing (T2-1), and A2058 T2R-7 under-expressing (T2R-7) TIMP-2. Compared to T2-1 cells at the basal level, T2R-7 showed significantly lower amount protein and weaker immunofluorescence staining of ß-catenin. This regulation is through posttranslational level via ubiquitination. Functionally, proliferation and cell growth were lower in T2R-7 compared to A2058 and T2-1. Lithium treatment was used to mimics activation of the Wnt/ß-catenin pathway. In T2R-7 cells under-expressing TIMP2, lithium significantly increased total ß-catenin, nuclear ß-catenin, and its downstream protein phosphor-c-Myc (S62). Nuclear ß-catenin staining was enhanced in T2R-7. Beta-catenin transcriptional activity and cell proliferation were also increased significantly. Axins inhibit ß-catenin pathway via GSK-3 ß. We further found the ratio of p-GSK-3 ß (S9) to ß-catenin and protein levels of Axins were significantly lower, whereas downstream Wnt 11 was high in T2R-7 treated with lithium. Collectively, the high level of TIMP-2 protein inhibits the activation of the Wnt/ß-catenin pathway, thus suppressing proliferation. Insights in the molecular mechanisms of TIMP-2 may provide promising opportunities for anti-proliferative therapeutic intervention.