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1.
Front Public Health ; 12: 1320932, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38439759

RESUMO

Backgrounds: Observational studies have shown that cigarette smoking is inversely associated with risk of rosacea, However, it remains uncertain whether this association is causal or it is a result of reverse causation, and whether this association is affected by drinking behaviors. Methods: This study utilized the summary-level data from the largest genome-wide association study (GWAS) for smoking, alcohol consumption, and rosacea. The objective was to investigate the effect of genetically predicted exposures to smoking and alcohol consumption on the risk of developing rosacea. Two-sample bidirectional Mendelian randomization (MR) was applied, accompanied by sensitive analyses to validate the robustness of findings. Furthermore, multivariable MR was conducted to evaluate the direct impact of smoking on rosacea. Results: A decreased risk of rosacea was observed in individuals with genetically predicted lifetime smoking [odds ratio (OR)MR - IVW = 0.53; 95% confidence interval (CI), 0.318-0.897; P = 0.017], and number of cigarettes per day (ORMR - IVW = 0.55; 95% CI, 0.358-0.845; P = 0.006). However, no significant associations were found between initiation of regular smoking, smoking cessation, smoking initiation, alcohol consumption and rosacea. Reverse MR analysis did not show any associations between genetic liability toward rosacea and smoking or alcohol drinking. Importantly, the effect of lifetime smoking and the number of cigarettes per day on rosacea remained significant even after adjusting for alcohol consumption in multivariable MR analysis. Conclusion: Smoking was causally related to a lower risk of rosacea, while alcohol consumption does not appear to be associated with risk of rosacea.


Assuntos
Estudo de Associação Genômica Ampla , Rosácea , Humanos , Análise da Randomização Mendeliana , Fumar/efeitos adversos , Fumar/epidemiologia , Consumo de Bebidas Alcoólicas/epidemiologia , Rosácea/epidemiologia
2.
J Dermatol Sci ; 113(3): 103-112, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38331641

RESUMO

BACKGROUND: TET2 participates in tumor progression and intrinsic immune homeostasis via epigenetic regulation. TET2 has been reported to be involved in maintaining epithelial barrier homeostasis and inflammation. Abnormal epidermal barrier function and TET2 expression have been detected in psoriatic lesions. However, the mechanisms underlying the role of TET2 in psoriasis have not yet been elucidated. OBJECTIVE: To define the role of TET2 in maintaining epithelial barrier homeostasis and the exact epigenetic mechanism in the dysfunction of the epidermal barrier in psoriasis. METHODS: We analyzed human psoriatic skin lesions and datasets from the GEO database, and detected the expression of TET2/5-hmC together with barrier molecules by immunohistochemistry. We constructed epidermal-specific TET2 knockout mice to observe the effect of TET2 deficiency on epidermal barrier function via toluidine blue penetration assay. Further, we analyzed changes in the expression of epidermal barrier molecules by immunofluorescence in TET2-specific knockout mice and psoriatic model mice. RESULTS: We found that decreased expression of TET2/5-hmC correlated with dysregulated barrier molecules in human psoriatic lesions. Epidermal-specific TET2 knockout mice showed elevated transdermal water loss associated with abnormal epidermal barrier molecules. Furthermore, we observed that TET2 knockdown in keratinocytes reduced filaggrin expression via filaggrin promoter methylation. CONCLUSION: Aberrant epidermal TET2 affects the integrity of the epidermal barrier through the epigenetic dysregulation of epidermal barrier molecules, particularly filaggrin. Reduced TET2 expression is a critical factor contributing to an abnormal epidermal barrier in psoriasis.


Assuntos
Dioxigenases , Psoríase , Animais , Humanos , Camundongos , Dioxigenases/deficiência , Dioxigenases/genética , Dioxigenases/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Epigênese Genética , Proteínas Filagrinas , Proteínas de Filamentos Intermediários/genética , Proteínas de Filamentos Intermediários/metabolismo , Queratinócitos/metabolismo , Camundongos Knockout , Psoríase/patologia
3.
J Control Release ; 367: 197-208, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38246205

RESUMO

Melanoma, one of the most devastating forms of skin cancer, currently lacks effective clinical treatments. Delivery of functional genes to modulate specific protein expression to induce melanoma cell apoptosis could be a promising therapeutic approach. However, transfecting melanoma cells using non-viral methods, particularly with cationic polymers, presents significant challenges. In this study, we synthesized three branched poly(ß-amino ester)s (HPAEs) with evenly distributed branching units but varying space lengths through a two-step "oligomer combination" strategy. The unique topological structure enables HPAEs to condense DNA to form nano-sized polyplexes with favorable physiochemical properties. Notably, HPAEs, especially HPAE-2 with intermediate branching unit space length, demonstrated significantly higher gene transfection efficiency than the leading commercial gene transfection reagent, jetPRIME, in human melanoma cells. Furthermore, HPAE-2 efficiently delivered the Bax-encoding plasmid into melanoma cells, leading to a pronounced pro-apoptotic effect without causing noticeable cytotoxicity. This study establishes a potent non-viral platform for gene transfection of melanoma cells by harnessing the distribution of branching units, paving the way for potential clinical applications of gene therapy in melanoma treatment.


Assuntos
Ésteres , Melanoma , Polímeros , Humanos , Transfecção , Ésteres/química , Melanoma/genética , Melanoma/terapia , Apoptose , Técnicas de Transferência de Genes
4.
J Biophotonics ; : e202300356, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-38041219

RESUMO

Cold atmospheric plasma (CAP) has been reported to kill melanoma cells in vitro and in vivo. BRAF and MEK inhibitors are targeted therapy agents for advanced melanoma patients with BRAF mutations. However, low overall survival and relapse-free survival are still tough challenges due to drug resistance. In this study, we confirmed that CAP alleviated innate drug resistance and promoted the anti-tumor effect of targeted therapy in A875 and WM115 melanoma cells in vitro. Further, we revealed that CAP altered the expression of various molecules concerning MAPK and PI3K-AKT pathways in A875 cells. This study demonstrates that CAP promises to work as adjuvant treatment with targeted therapy to overcome drug resistance for malignant tumors in future.

5.
Nat Commun ; 13(1): 1859, 2022 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-35388001

RESUMO

The cohesin complex participates in the organization of 3D genome through generating and maintaining DNA loops. Stromal antigen 2 (STAG2), a core subunit of the cohesin complex, is frequently mutated in various cancers. However, the impact of STAG2 inactivation on 3D genome organization, especially the long-range enhancer-promoter contacts and subsequent gene expression control in cancer, remains poorly understood. Here we show that depletion of STAG2 in melanoma cells leads to expansion of topologically associating domains (TADs) and enhances the formation of acetylated histone H3 lysine 27 (H3K27ac)-associated DNA loops at sites where binding of STAG2 is switched to its paralog STAG1. We further identify Interferon Regulatory Factor 9 (IRF9) as a major direct target of STAG2 in melanoma cells via integrated RNA-seq, STAG2 ChIP-seq and H3K27ac HiChIP analyses. We demonstrate that loss of STAG2 activates IRF9 through modulating the 3D genome organization, which in turn enhances type I interferon signaling and increases the expression of PD-L1. Our findings not only establish a previously unknown role of the STAG2 to STAG1 switch in 3D genome organization, but also reveal a functional link between STAG2 and interferon signaling in cancer cells, which may enhance the immune evasion potential in STAG2-mutant cancer.


Assuntos
Proteínas Cromossômicas não Histona , Melanoma , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas Cromossômicas não Histona/genética , Proteínas Cromossômicas não Histona/metabolismo , Genoma , Humanos , Interferons/genética , Melanoma/genética
6.
J Biophotonics ; 15(6): e202100403, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35261164

RESUMO

Cold atmospheric plasma (CAP) has attracted increasing attention due to its anti-bacterial and anti-tumor effects. Melanoma is an aggressive malignancy with increasing incidence rate and poor prognosis. Evaluating cell viability, apoptosis rate and reactive species injection efficiency of melanoma cells and human keratinocyte cells (HaCaT) treated with CAP to analyze biological safety of CAP. RNA-sequencing (RNA-seq) of A875 cells before and after treatment was performed to further explore the anti-tumor mechanism of CAP. CAP had a more significant biological effect on melanoma cells than HaCaT cells by inhibiting proliferation and promoting apoptosis. RNA-sequencing analysis showed that besides MAPK and p53 apoptotic signaling pathways, necroptosis and autophagy also played important roles in CAP-induced melanoma cells death. CAP can selectively kill melanoma cells and has good biosafety cytologically. Besides apoptosis, CAP can induce cell death via autophagy and necroptosis.


Assuntos
Melanoma , Gases em Plasma , Apoptose/genética , Linhagem Celular Tumoral , Contenção de Riscos Biológicos , Humanos , Melanoma/genética , Melanoma/patologia , Gases em Plasma/farmacologia , RNA/farmacologia
7.
Int J Biochem Cell Biol ; 145: 106190, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35248720

RESUMO

OBJECTIVES: With the growing incidence of cutaneous squamous cell carcinoma (CSCC), the treatment-resistant invasive CSCC should be taken seriously. Retinoic acid receptor ß (RARß) functions as a tumor suppressor gene and is associated with the proliferation inhibition to retinoic acid. Demethylase TET2 directed epigenetic landscape contributes to cell malignant transform and is involved in therapeutic resistance in tumors. Whether aberrant TET2 participated in the deficient RARß remains largely unknown. Hereby, we identified the aberrant-TET2 directed epigenetic landscape contribute to the deficient RARß in CSCC. METHODS: The immunohistochemistry was used to detect the expression of RARß and TET2. The bisulfite sequencing PCR was used to detect the RARß promoter methylation. Plasmid transfection was used to upregulate TET2 in CSCC cells. Stable overxpressed TET2 cells were used to detect the effect of TET2 on RARß and drug sensitivity in the CCSC. RESULTS: We observed RARß decreased with promoter hypermethylation in CSCC and aberrant TET2 associated with deficient RARß. We upregulated TET2 could reverse promoter hypermethylation and showed a significantly increased expression of RARß, which enhanced the sensitivity of tumor cells to retinoic acid treatment. CONCLUSION: Aberrant TET2 leaded to the hypermethylation of RARß promoter, which contributed to the deficient RARß in CSCC. While reversing the hypermethylation of the RARß promoter by recovering the TET2 could enhance tumor cells to be sensitive to retinoic acid.


Assuntos
Carcinoma de Células Escamosas , Dioxigenases , Neoplasias Cutâneas , Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/metabolismo , Metilação de DNA , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Dioxigenases/genética , Dioxigenases/metabolismo , Epigênese Genética , Humanos , Receptores do Ácido Retinoico , Neoplasias Cutâneas/tratamento farmacológico , Neoplasias Cutâneas/genética , Tretinoína/farmacologia
8.
J Microbiol Biotechnol ; 31(5): 747-755, 2021 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-33746191

RESUMO

The effects of the gut microbiome on both allergy and autoimmunity in dermatological diseases have been indicated in several recent studies. Chronic spontaneous urticaria (CSU) is a disease involving allergy and autoimmunity, and there is no report detailing the role of microbiota alterations in its development. This study was performed to identify the fecal microbial composition of CSU patients and investigate the different compositions and potential genetic functions on the fecal microbiota between CSU patients and normal controls. The gut microbiota of CSU patients and healthy individuals were obtained by 16s rRNA massive sequencing. Gut microbiota diversity and composition were compared, and bioinformatics analysis of the differences was performed. The gut microbiota composition results showed that Firmicutes, Bacteroidetes, Proteobacteria, and Verrucomicrobia were dominant microbiota in CSU patients. The differential analysis showed that relative abundance of the Proteobacteria (p = 0.03), Bacilli (p = 0.04), Enterobacterales (p = 0.03), Enterobacteriaceae (p = 0.03) was significantly increased in CSU patients. In contrast, the relative abundance of Megamonas, Megasphaera, and Dialister (all p < 0.05) in these patients significantly decreased compared with healthy controls. The different microbiological compositions impacted normal gastrointestinal functions based on function prediction, resulting in abnormal pathways, including transport and metabolism. We found CSU patients exhibited gut microbiota dysbiosis compared with healthy controls. Our results indicated CSU is associated with gut microbiota dysbiosis and pointed out that the bacterial taxa increased in CSU patients, which might be involved in the pathogenesis of CSU. These results provided clues for future microbial-based therapies on CSU.


Assuntos
Urticária Crônica/microbiologia , Microbioma Gastrointestinal , Adulto , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Disbiose/microbiologia , Fezes/microbiologia , Feminino , Microbioma Gastrointestinal/genética , Humanos , Masculino , RNA Ribossômico 16S/genética
9.
J Biomech ; 119: 110208, 2021 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-33662748

RESUMO

Measuring the location of necrotic lesions is necessary to diagnosis of osteonecrosis. Different region segmentation methods of the femoral head were proposed to quantitatively measure necrotic lesions including Japanese Investigation Committee for Avascular Necrosis (JIC) classification and China-Japan Friendship Hospital (CJFH) classification. Biomechanical methods could bring important information to evaluate the reasonability of these classifications. In this study, microstructural and mechanical properties of trabecular bone were quantitatively analyzed according to the region segmentation methods described in these classifications. Microstructural parameters of trabecular bone were analyzed based on micro-CT scanning. Mechanical properties were measured through Nanoindentation and micro-finite element analysis. It was found that microstructural and mechanical properties of trabecular bone in the middle region was more adaptive to load bearing than the medial and lateral regions according to the CJFH classification; lesions in the middle region could bring more changes to microstructure and stress distribution. According to JIC classification, differences of microstructural and mechanical properties among the three regions were not significant. Biomechanical characteristics of trabecular bones could be better distinguished with CJFH classification.


Assuntos
Osteonecrose , Cabeça do Fêmur , Análise de Elementos Finitos , Humanos , Osteonecrose/diagnóstico por imagem , Estresse Mecânico , Suporte de Carga , Microtomografia por Raio-X
10.
J Biomed Mater Res A ; 109(4): 515-523, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-32506791

RESUMO

Porous three-dimensional (3D) silk fibroin (SF) scaffolds were widely applied for bone regeneration and showed excellent biocompatibility and biodegradability. Recently graphene was developed for bone scaffolds due to its osteogenic properties. Thus, we combine the SF and graphene to improve the osteogenic properties of SF scaffolds. In our study, we explored the incorporation of SF scaffolds with graphene to develop osteogenic scaffolds capable of accelerating bone formation. The 3D SF scaffolds were fabricated with different contents of graphene (0, 0.5, and 2%). Fluorescence images showed that the graphene nanosheets were homogeneously dispersed in the SF scaffolds. The addition of graphene affected the microarchitecture of the scaffolds. The G/SF scaffolds were cocultured with rat bone marrow-derived mesenchymal stem cells (rBMSCs) for 21 days. The cell morphology and cell proliferation study suggested that 0 and 0.5% G/SF scaffolds displayed good cell proliferation. In addition, immunofluorescent staining (e.g., osteonectin, osteopontin, and osteocalcin) and ALP activities indicated that the osteogenic properties was more actively exhibited on 0.5% G/SF scaffolds compared with the other groups. Our results indicated that SF scaffolds incorporated with graphene could be an appropriate scaffold for bone tissue engineering.


Assuntos
Regeneração Óssea , Fibroínas/química , Grafite/química , Células-Tronco Mesenquimais/citologia , Tecidos Suporte/química , Animais , Diferenciação Celular , Proliferação de Células , Células Cultivadas , Ratos , Engenharia Tecidual/métodos
11.
Cancer Invest ; 39(1): 84-97, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33058714

RESUMO

Ubiquitin like with PHD and ring finger domains 1 (UHRF1) contributes to the progression of many cancers. Here, we firstly observed UHRF1 was elevated in cutaneous squamous cell carcinoma (cSCC) and related to the differentiation stages. Knockdown of UHRF1 in A431 and Scl-1 attenuated cell proliferation, migration, and invasion, leading to G2/M cell cycle arrest and apoptosis. Through a mouse xenograft model, we found UHRF1 deficiency ameliorated tumor growth. These results may be associated with destruction of multiple signal pathways. In summary, our results suggest UHRF1 is involved in the pathogenesis of cSCC and may be a therapeutic target.


Assuntos
Proteínas Estimuladoras de Ligação a CCAAT/genética , Ubiquitina-Proteína Ligases/genética , Animais , Carcinoma de Células Escamosas/patologia , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Feminino , Humanos , Camundongos , Camundongos Nus , Invasividade Neoplásica , Transdução de Sinais , Neoplasias Cutâneas/patologia
12.
Int J Oncol ; 54(5): 1534-1544, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30816486

RESUMO

Cell division cycle 20 (CDC20) is a regulatory molecule and serves critical roles at multiple points of the cell cycle. Recent evidence indicates that CDC20 may serve an oncogenic role in a number of human cancer types. However, the role of CDC20 in primary cutaneous squamous cell carcinoma (cSCC) has not been studied, to the best of our knowledge. The aim of the present study was to investigate whether and how CDC20 is involved in the tumorigenesis of cSCC. The results revealed that CDC20 expression was significantly increased in cSCC tissues and cell lines, and its expression was associated with pathological differentiation. Downregulation of CDC20 inhibited cell proliferation, induced cell cycle arrest, promoted apoptosis and reduced migratory ability through inhibition of the Wnt/ß­catenin signaling pathway. Furthermore, all­trans­retinoic acid treatment significantly downregulated CDC20 expression in cSCC. The present results revealed that CDC20 may serve a crucial role in human cSCC, and suggested that CDC20 may be a novel biomarker for the prevention, diagnosis and treatment of cSCC.


Assuntos
Carcinoma de Células Escamosas/metabolismo , Proteínas Cdc20/genética , Proteínas Cdc20/metabolismo , Neoplasias Cutâneas/metabolismo , Regulação para Cima , Via de Sinalização Wnt , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/patologia , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Criança , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/patologia , Adulto Jovem
13.
J Invest Dermatol ; 139(4): 796-806, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30414907

RESUMO

Recent studies showed that TWEAK/Fn14 signaling participates in the progression of internal malignancies. However, its role in the biological properties of cutaneous squamous cell carcinoma (SCC) remains unclear. This study was designed to explore the effect of TWEAK/Fn14 activation on cutaneous SCC as well as the relevant mechanism. The expression of TWEAK and Fn14 was determined in tissue samples of patients with cutaneous SCC. Human primary keratinocytes and SCC cell lines were cultured in vitro, receiving stimulation of TWEAK. The xenografts of SCC were generated subcutaneously in BALB/c nude mice. The results showed that both TWEAK and Fn14 were highly expressed in human cutaneous SCC. Moreover, TWEAK/Fn14 activation promoted the proliferation, migration, and invasion of cultured SCC cells. Interestingly, TNFR2 was upregulated in cultured SCC cells, and the transfection of TNFR2 small interfering RNA abrogated the effect of TWEAK on these cells. Finally, the favorable effect of TWEAK/Fn14 signals was confirmed in BALB/c nude mice with SCC xenografts. In conclusion, TWEAK/Fn14 signals contribute to the progression of cutaneous SCC, possibly involving the TNF-α-independent TNFR2 signal transduction.


Assuntos
Carcinoma de Células Escamosas/genética , DNA de Neoplasias/genética , Regulação Neoplásica da Expressão Gênica , Neoplasias Cutâneas/genética , Pele/patologia , Receptor de TWEAK/genética , Western Blotting , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patologia , Linhagem Celular Tumoral , Proliferação de Células , Progressão da Doença , Humanos , Imuno-Histoquímica , Transdução de Sinais , Pele/metabolismo , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/patologia , Receptor de TWEAK/biossíntese
14.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 35(6): 887-891, 2018 12 26.
Artigo em Chinês | MEDLINE | ID: mdl-30583313

RESUMO

Muscle atrophy of the residual limb after lower-limb amputation is a disadvantage of amputees' rehabilitation. To investigate the biomechanics mechanism of muscle atrophy of the residual limb, we built a finite element model of a residual limb including muscle, skeletons and main vessels based on magnetic resonance images of a trans-femoral amputee, and studied the biomechanics effects of the socket of the lower-limb prosthesis on the soft tissue and vessels in the residual limb. It was found that the descending branch of the lateral femoral circumflex artery suffered the most serious constriction due to the extrusion, while that of the deep femoral artery was comparatively light. Besides, the degree of the constriction of the descending branch of the lateral femoral circumflex vein, femoral vein and deep femoral vein decreased in turn, and that of the great saphenous vein was serious. The stress-strain in the anterior femoral muscle group were highest, while the stress concentration of the inferior muscle group was observed at the end of the thighbone, and other biomechanical indicators at the inferior region were also high. This study validated that the extrusion of the socket on the vessels could cause muscle atrophy to some degree, and provided theoretical references for learning the mechanism of muscle atrophy in residual limb and its effective preventive measures.

15.
Biomed Res Int ; 2018: 4025083, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30515396

RESUMO

Osteogenic differentiation of cells has considerable clinical significance in bone defect treatment, and cell behavior is linked to extracellular matrix stiffness. This study aimed to determine how matrix stiffness affects cell morphology and subsequently regulates the osteogenic phenotype of osteogenesis precursor cells. Four PDMS substrates were prepared with stiffness corresponding to the elastic modulus ranging from 0.6 MPa to 2.7 MPa by altering the Sylgard 527 and Sylgard 184 concentrations. MC3T3-E1 cells were cultured on the matrices. Cell morphology, vinculin expression, and key osteogenic markers, Col I, OCN, OPN, and calcium nodule, were examined. The activity and expression level of Yes-associated protein (YAP) were evaluated. Results showed that cell spreading exhibited no correlation with the stiffness of matrix designed in this paper, but substratum stiffness did modulate MC3T3-E1 osteogenic differentiation. Col I, OPN, and OCN proteins were significantly increased in cells cultured on soft matrices compared with stiff matrices. Additionally, cells cultured on the 1:3 ratio matrices had more nodules than those on other matrices. Accordingly, cells on substrates with low stiffness showed enhanced expression of the osteogenic markers. Meanwhile, YAP expression was downregulated on soft substrates although the subcellular location was not affected. Our results provide evidence that matrix stiffness (elastic modulus ranging from 0.6 MPa to 2.7 MPa) affects the osteogenic differentiation of MC3T3-E1, but it is not that "the stiffer, the better" as showed in some of the previous studies. The optimal substrate stiffness may exist to promote osteoblast differentiation. Cell differentiation triggered by the changes in substrate stiffness may be independent of the YAP signal. This study has important implications for biomaterial design and stem cell-based tissue engineering.


Assuntos
Desenvolvimento Ósseo/genética , Diferenciação Celular/genética , Osteogênese/genética , Engenharia Tecidual , Células 3T3 , Animais , Proliferação de Células/genética , Forma Celular/genética , Elasticidade/fisiologia , Matriz Extracelular/genética , Humanos , Camundongos , Osteoblastos/citologia , Osteoblastos/metabolismo
16.
J Biomech ; 74: 98-105, 2018 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-29735265

RESUMO

Insufficient scaffolding time in the process of rapid corrosion is the main problem of magnesium alloy stent (MAS). Finite element method had been used to investigate corrosion of MAS. However, related researches mostly described all elements suffered corrosion in view of one-dimensional corrosion. Multi-dimensional corrosions significantly influence mechanical integrity of MAS structures such as edges and corners. In this study, the effects of multi-dimensional corrosion were studied using experiment quantitatively, then a phenomenological corrosion model was developed to consider these effects. We implemented immersion test with magnesium alloy (AZ31B) cubes, which had different numbers of exposed surfaces to analyze differences of dimension. It was indicated that corrosion rates of cubes are almost proportional to their exposed-surface numbers, especially when pitting corrosions are not marked. The cubes also represented the hexahedron elements in simulation. In conclusion, corrosion rate of every element accelerates by increasing corrosion-surface numbers in multi-dimensional corrosion. The damage ratios among elements with the same size are proportional to the ratios of corrosion-surface numbers under uniform corrosion. The finite element simulation using proposed model provided more details of changes of morphology and mechanics in scaffolding time by removing 25.7% of elements of MAS. The proposed corrosion model reflected the effects of multi-dimension on corrosions. It would be used to predict degradation process of MAS quantitatively.


Assuntos
Implantes Absorvíveis , Ligas/química , Magnésio/química , Stents , Corrosão , Análise de Elementos Finitos
17.
Regen Biomater ; 4(3): 179-190, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28596915

RESUMO

Aliphatic biodegradable polyesters have been the most widely used synthetic polymers for developing biodegradable devices as alternatives for the currently used permanent medical devices. The performances during biodegradation process play crucial roles for final realization of their functions. Because physiological and biochemical environment in vivo significantly affects biodegradation process, large numbers of studies on effects of mechanical loads on the degradation of aliphatic biodegradable polyesters have been launched during last decades. In this review article, we discussed the mechanism of biodegradation and several different mechanical loads that have been reported to affect the biodegradation process. Other physiological and biochemical factors related to mechanical loads were also discussed. The mechanical load could change the conformational strain energy and morphology to weaken the stability of the polymer. Besides, the load and pattern could accelerate the loss of intrinsic mechanical properties of polymers. This indicated that investigations into effects of mechanical loads on the degradation should be indispensable. More combination condition of mechanical loads and multiple factors should be considered in order to keep the degradation rate controllable and evaluate the degradation process in vivo accurately. Only then can the degradable devise achieve the desired effects and further expand the special applications of aliphatic biodegradable polyesters.

18.
Angew Chem Int Ed Engl ; 56(10): 2749-2753, 2017 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-28128509

RESUMO

Compared to the most popular directing-group-assisted strategy, the "undirected" strategy for C-H bond functionalization represents a more flexible but more challenging approach. Reported herein is a gold-catalyzed highly site-selective C(sp2 )-H alkylation of unactivated arenes with 2,2,2-trifluoroethyl α-aryl-α-diazoesters. This protocol demonstrates that high site-selective C-H bond functionalization can be achieved without the assistance of a directing group. In this transformation, both the gold catalyst and trifluoroethyl group on the ester of the diazo compound play vital roles for achieving the chemo- and regioselectivity.

19.
Oncol Rep ; 37(1): 139-146, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27878257

RESUMO

Epithelial-mesenchymal transition (EMT) contributes to the invasion and metastasis of numerous malignant cancers, including melanoma. A significant higher expression of B-lymphoma Moloney murine leukemia virus insertion region-1 (Bmi-1) has been reported in cell lines from metastatic melanoma compared to cell lines from primary melanoma. There are studies that show that knockdown of Bmi-1 could induce E-cadherin expression in melanoma cells. However, the role of Bmi-1 in mediating EMT-like changes in melanoma has not yet been fully studied. In the present study, knockdown of Bmi-1 by shRNA transduction decreased the invasion properties of the cultured human melanoma cells A375 by a Matrigel invasion assay, along with alterations in EMT-related markers E-cadherin, α-catenin, vimentin and N-cadherin. The aforementioned altered expression of EMT markers was verified in BALB/c-nude mouse xenografts. Furthermore, to explore the underlying regulatory mechanism of EMT, we detected the significant downregulation of p-Akt/p­NF-κB/MMP-2 and the upregulation of PTEN in Bmi-1-silenced A375 cells. The present study demonstrated that knockdown of Bmi-1 significantly inhibited the aggressive behavior of melanoma by reversing EMT-like changes via the PTEN/p-Akt/p­NF-κB/MMP-2 pathway.


Assuntos
Transição Epitelial-Mesenquimal/genética , Melanoma/genética , Melanoma/patologia , Complexo Repressor Polycomb 1/genética , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/patologia , Animais , Linhagem Celular Tumoral , Regulação para Baixo/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Metástase Neoplásica , Complexo Repressor Polycomb 1/antagonistas & inibidores , Transdução de Sinais/genética , Ensaios Antitumorais Modelo de Xenoenxerto
20.
J Biomed Mater Res A ; 105(1): 23-30, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27507409

RESUMO

The applications of poly (lactide-co-glycolide) acid (PLGA) for coating or fabricating polymeric biodegradable stents (BDSs) have drawn more attention. The fluid shear stress has been proved to affect the in vitro degradation process of PLGA membranes. During the maintenance, BDSs could be suffered different patterns of fluid shear stress, but the effect of these different patterns on the whole degradation process is unclear. In this study, in vitro degradation of PLGA membranes was examined with steady, sinusoid, and squarewave fluid shear stress patterns in 150 mL deionized water at 37°C for 20 days, emphasizing on the changes in the viscosity of the degradation solution, mechanical, and morphological properties of the samples. The unsteady fluid shear stress with the same average magnitude as the steady one accelerate the in vitro degradation process of PLGA membranes in terms of maximum fluid shear stress and "window" of effectiveness. Maximum fluid shear stress accelerates the in vitro degradation of molecular fragments that diffused out in the solution while the "window" of effectiveness affects too in the early stage. Besides, maximum fluid shear stress and "window" of effectiveness accelerates the in vitro loss of tensile modulus and ultimate strength of the PLGA membranes while the maximum fluid shear stress plays the leading role in the decrease of tensile modulus at the early degradation stage. This study could help advance the degradation design of PLGA membranes under different fluid shear stress patterns for biomedical applications like stents and drug release systems. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 23-30, 2017.


Assuntos
Teste de Materiais , Membranas Artificiais , Poliglactina 910/química , Resistência ao Cisalhamento
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