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1.
Cell Mol Biol (Noisy-le-grand) ; 70(5): 226-232, 2024 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-38814209

RESUMO

This study aims to analyze the active components and mechanism of Bushen Huoxue (BSHX) formula on the autoimmune premature ovarian insufficiency (POI) by combining network pharmacology and Transcriptomics. The active components and targets of BSHXF were screened through Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP). POI-related targets were identified through Therapeutic Targets Database (TTD), DisGeNET and drugbank database. The Veen diagram was performed to obtain the action targets. The active compound-target network and Protein-Protein Interaction (PPI) network were built by using STRING database and Cytoscape software. Key targets and active compounds were further identified by topological analysis. Molecular docking shows that Kaempferol, Isorhamnetin and Anhydroicaritin have strong binding to AKT. Finally, a zp3-induced autoimmune ovarian function deficiency mouse model was used to explore the potential mechanism of POI. The potential pathways of BSHXF for the treatment of POI were identified by Transcriptomic analysis. PI3K-AKT and NF-kb pathways were the common pathways between network pharmacology and transcriptomics. Our results revealed that BSHXF could reduce the FSH expression levels and raise the E2, and AMH levels in the serum. Western bloting demonstrates that BSHXF could upregulate the expression of p-PI3K and p-AKT.


Assuntos
Medicamentos de Ervas Chinesas , Simulação de Acoplamento Molecular , Farmacologia em Rede , Fosfatidilinositol 3-Quinases , Insuficiência Ovariana Primária , Mapas de Interação de Proteínas , Proteínas Proto-Oncogênicas c-akt , Transdução de Sinais , Insuficiência Ovariana Primária/tratamento farmacológico , Insuficiência Ovariana Primária/genética , Insuficiência Ovariana Primária/metabolismo , Feminino , Medicamentos de Ervas Chinesas/farmacologia , Medicamentos de Ervas Chinesas/química , Medicamentos de Ervas Chinesas/uso terapêutico , Proteínas Proto-Oncogênicas c-akt/metabolismo , Animais , Fosfatidilinositol 3-Quinases/metabolismo , Transdução de Sinais/efeitos dos fármacos , Mapas de Interação de Proteínas/efeitos dos fármacos , Camundongos , Perfilação da Expressão Gênica , Transcriptoma/efeitos dos fármacos , Transcriptoma/genética , Modelos Animais de Doenças , Humanos
2.
Biochim Biophys Acta Mol Basis Dis ; 1870(4): 167121, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38471652

RESUMO

BACKGROUND: Sjögren's syndrome (SS) is a chronic autoimmune disease that predominantly affects exocrine glands. Previous studies have demonstrated that upregulated interferon-gamma (IFN-γ) in SS triggers ferroptosis in salivary gland epithelial cells (SGECs), resulting in impaired salivary gland secretion. However, the immune cells responsible for secreting IFN-γ remain unclear. Therefore, this study conducted bioinformatics analysis and molecular validation to identify the origin of IFN-γ in SS salivary gland. METHODS: The 'limma' package in R software was utilized to identify differentially expressed genes (DEGs) in the human SS dataset. Subsequently, the identified DEGs were compared with the ferroptosis database and screened through Cytoscape to determine candidate genes. The cellular localization and expression patterns of candidate genes were further confirmed in the salivary gland single-cell RNA sequence (scRNA-seq) data set from healthy control and SS mice. Furthermore, in vitro and in vivo studies were performed to analyze the effect of CD4 T-secreted IFN-γ on SGECs' ferroptosis and functions. RESULTS: Upregulated TLR4, IFNG, and IL33 were screened as candidates ferroptosis ferroptosis-inducing genes in SS salivary glands. The association of IFNG and IL33 with CD4 T cells was established through immune infiltration analysis. The expression of IFN-γ on CD4 T cells was robustly higher compared with that of IL33 as evidenced by scRNA-seq and immunofluorescence co-localization. Subsequent experiments conducted on candidate genes consistently demonstrated the potent ability of IFN-γ to induce SGECs' ferroptosis and inhibit AQP5 expression. CONCLUSIONS: Our findings indicate that CD4 T cell-secreted IFN-γ in SS induces SGECs' ferroptosis and inhibits AQP5 expression.


Assuntos
Ferroptose , Síndrome de Sjogren , Humanos , Animais , Camundongos , Interferon gama/metabolismo , Linfócitos T CD4-Positivos , Interleucina-33/metabolismo , Glândulas Salivares , Células Epiteliais/metabolismo
5.
Nat Biomed Eng ; 8(3): 291-309, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37996617

RESUMO

Mapping mutations and discovering cellular determinants that cause the spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to induce infected cells to form syncytia would facilitate the development of strategies for blocking the formation of such cell-cell fusion. Here we describe high-throughput screening methods based on droplet microfluidics and the size-exclusion selection of syncytia, coupled with large-scale mutagenesis and genome-wide knockout screening via clustered regularly interspaced short palindromic repeats (CRISPR), for the large-scale identification of determinants of cell-cell fusion. We used the methods to perform deep mutational scans in spike-presenting cells to pinpoint mutable syncytium-enhancing substitutions in two regions of the spike protein (the fusion peptide proximal region and the furin-cleavage site). We also used a genome-wide CRISPR screen in cells expressing the receptor angiotensin-converting enzyme 2 to identify inhibitors of clathrin-mediated endocytosis that impede syncytium formation, which we validated in hamsters infected with SARS-CoV-2. Finding genetic and cellular determinants of the formation of syncytia may reveal insights into the physiological and pathological consequences of cell-cell fusion.


Assuntos
COVID-19 , SARS-CoV-2 , Humanos , Ensaios de Triagem em Larga Escala , Glicoproteína da Espícula de Coronavírus/genética , COVID-19/patologia , Células Gigantes/metabolismo , Células Gigantes/patologia
6.
Free Radic Biol Med ; 205: 116-128, 2023 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-37286044

RESUMO

The elevated level of interferon-γ (IFN-γ) in Sjogren's syndrome (SS) triggers salivary gland epithelial cells (SGEC) death. However, the underlying mechanisms of IFN-γ-induced SGEC death modes are still not fully elucidated. We found that IFN-γ triggers SGEC ferroptosis via Janus kinase/signal transducer and activator of transcription 1 (JAK/STAT1)-mediated inhibition of cystine-glutamate exchanger (System Xc-). Transcriptome analysis revealed that ferroptosis-related markers are differentially expressed in SS human and mouse salivary glands with distinct upregulation of IFN-γ and downregulation of glutathione peroxidase 4 (GPX4) and aquaporin 5 (AQP5). Inducing ferroptosis or IFN-γ treatment in the Institute of cancer research (ICR) mice aggravated and inhibition of ferroptosis or IFN-γ signaling in SS model non-obese diabetic (NOD) mice alleviated ferroptosis in the salivary gland and SS symptoms. IFN-γ activated STAT1 phosphorylation and downregulated system Xc- components solute carrier family 3 member 2 (SLC3A2), glutathione, and GPX4 thereby triggering ferroptosis in SGEC. JAK or STAT1 inhibition in SGEC rescued IFN-γ-downregulated SLC3A2 and GPX4 as well as IFN-γ-induced cell death. Our results indicate the role of ferroptosis in SS-related death of SGEC and SS pathogenicity.


Assuntos
Ferroptose , Síndrome de Sjogren , Animais , Humanos , Camundongos , Células Epiteliais/metabolismo , Ferroptose/genética , Interferon gama/metabolismo , Camundongos Endogâmicos NOD , Glândulas Salivares/metabolismo , Síndrome de Sjogren/genética , Síndrome de Sjogren/metabolismo , Fator de Transcrição STAT1/genética , Fator de Transcrição STAT1/metabolismo , Janus Quinases/metabolismo
7.
J Transl Med ; 21(1): 361, 2023 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-37268950

RESUMO

BACKGROUND: Restoration of salivary gland function in Sjogren's syndrome (SS) is still a challenge. Dental pulp stem cells (DPSCs) derived exosomes had shown anti-inflammatory, anti-oxidative, immunomodulatory, and tissue function restorative abilities. However, the salivary gland function restoration potential of DPSCs-derived exosomes (DPSC-Exos) during SS has not been investigated yet. METHODS: DPSC-Exos was isolated by ultracentrifugation methods and characterized. Salivary gland epithelial cells (SGEC) were treated with interferon-gamma (IFN-γ) to mimic SS in vitro and cultured with or without DPSC-Exos. SGEC survival and aquaporin 5 (AQP5) expression were analyzed. mRNA sequencing and bioinformatics analysis were performed in IFN-γ vs. DPSC-Exos+ IFN-γ treated SGEC. Non-obese diabetic (NOD)/ltj female mice (SS model), were intravenously administered with DPSC-Exos, and salivary gland functions and SS pathogenicity were analyzed. Furthermore, the mRNA sequencing and bioinformatics predicted mechanism of the therapeutic effect of DPSC-Exos was further investigated both in vitro and in vivo using RT-qPCR, Western blot, immunohistochemistry, immunofluorescence, flowcytometry analysis. RESULTS: DPSC-Exos partially rescued IFN-γ triggered SGEC death. IFN-γ inhibited AQP5 expression in SGEC and DPSC-Exos reversed this effect. Transcriptome analysis showed GPER was the upregulated DEG in DPSC-Exos-treated SGEC with a positive correlation with salivary secretion-related DEGs. Pathway enrichment analysis revealed that DEGs were mainly attributed to estrogen 16 alpha-hydroxylase activity, extracellular exosome function, cAMP signaling, salivary secretion, and estrogen signaling. Intravenous injection of DPSC-Exos in NOD/ltj mice alleviated the SS syndrome as indicated by the increased salivary flow rate, attenuated glandular inflammation, and increased AQP5 expression. GPER was also upregulated in the salivary gland of DPSC-Exos-treated NOD/ltj mice compared with the PBS-treated NOD/ltj mice. IFN-γ+DPSC-Exos-treated SGEC showed higher expression of AQP5, p-PKA, cAMP, and intracellular Ca2+ levels compared with IFN-γ-treated SGEC. These effects were reversed by the inhibition of GPER. CONCLUSIONS: Our results showed that DPSC-Exos revitalize salivary gland epithelial cell function during SS via the GPER-mediated cAMP/PKA/CREB pathway suggesting the possible therapeutic potential of DPSC-Exos in SS-treatment.


Assuntos
Polpa Dentária , Exossomos , Glândulas Salivares , Síndrome de Sjogren , Humanos , Animais , Camundongos , Polpa Dentária/citologia , Células Cultivadas , Exossomos/metabolismo , Feminino , Camundongos Endogâmicos NOD , Interferon gama/farmacologia , Glândulas Salivares/citologia , Células Epiteliais/metabolismo , Síndrome de Sjogren/terapia
8.
Microsyst Nanoeng ; 9: 24, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36910256

RESUMO

Droplet merging serves as a powerful tool to add reagents to moving droplets for biological and chemical reactions. However, unsynchronized droplet pairing impedes high-efficiency merging. Here, we develop a microfluidic design for the self-synchronization of reinjected droplets. A periodic increase in the hydrodynamic resistance caused by droplet blocking a T-junction enables automatic pairing of droplets. After inducing spacing, the paired droplets merge downstream under an electric field. The blockage-based design can achieve a 100% synchronization efficiency even when the mismatch rate of droplet frequencies reaches 10%. Over 98% of the droplets can still be synchronized at nonuniform droplet sizes and fluctuating reinjection flow rates. Moreover, the droplet pairing ratio can be adjusted flexibly for on-demand sample addition. Using this system, we merge two groups of droplets encapsulating enzyme/substrate, demonstrating its capacity to conduct multi-step reactions. We also combine droplet sorting and merging to coencapsulate single cells and single beads, providing a basis for high-efficiency single-cell sequencing. We expect that this system can be integrated with other droplet manipulation systems for a broad range of chemical and biological applications.

9.
Heliyon ; 9(2): e13205, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36814621

RESUMO

As the main bioactive substance of Ganoderma lucidum, Ganoderma lucidum polysaccharide (GLP) has anti-inflammatory, antibacterial, and other biological activities. Studies have shown that GLP can regulate the expression of multiple inflammatory cytokines in different inflammatory models and diseases as part of the anti-infection immune response. We extracted crude Changbai Mountain Ganoderma lucidum polysaccharides (CGLPs), analyzed their physical and chemical properties, and then applied them to the periodontitis model to verify whether they have an inhibitory effect on mouse periodontitis. CGLP was determined to be a heteropolysaccharide with dextran as the main component. Its molecular weight was 17.40 kDa. In vivo experiments in mice showed that CGLP can inhibit the alveolar bone loss and reduced inflammation caused of periodontitis by regulating the expression of the inflammatory factors IL-1ß, TNF-α, and IL-10 in a concentration-dependent manner.

10.
Front Oncol ; 12: 1029998, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36531013

RESUMO

Diffuse large B-cell lymphoma (DLBCL) is a highly heterogeneous malignancy. Epidemiologically, the incidence of DLBCL is higher in men, and the female sex is a favorable prognostic factor, which can be explained by estrogen. This study aimed to explore the potential targets of the estrogen receptor (ER) signaling pathway and provide a meaningful way to treat DLBCL patients. Datasets were obtained from the Gene Expression Omnibus (GEO) to identify differentially expressed genes (DEGs). Representative gene sets estrogen receptor pathways, and growth regulatory pathways were identified based on Gene Set Enrichment Analysis (GSEA) analysis. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were used for function and pathway analysis. STRING and Cytoscape were used to construct the interaction network, and the MCODE plug-in performed the module analysis. GEPIA, TCGA, and LOGpc databases were used for expression and predictive analysis. The Human Protein Atlas (HPA) database was used to analyze the protein expression levels, cBioPortal was used to explore genetic alterations, and ROC analysis and prognostic assessment were used to predict the diagnostic value of genes. Finally, BJAB cells were treated with ER inhibitor fulvestrant and specific shRNA, and the expression of hub genes was verified by RT-qPCR. We identified 81 overlapping DEGs and CDC6, CDC20, KIF20A, STIL, and TOP2A as novel biomarkers affecting the prognosis of DLBCL. In addition, the STAT and KRAS pathways are considered potential growth regulatory pathways. These results hold promise for new avenues for the treatment of DLBCL patients.

11.
Biol Proced Online ; 24(1): 26, 2022 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-36575389

RESUMO

BACKGROUND: Sjogren's syndrome (SS) is an autoimmune disorder characterized by the destruction of exocrine glands, resulting in dry mouth and eyes. Currently, there is no effective treatment for SS, and the mechanisms associated with inadequate salivary secretion are poorly understood. METHODS: In this study, we used NOD mice model to monitor changes in mice's salivary secretion and water consumption. Tissue morphology of the submandibular glands was examined by H&E staining, and Immunohistochemical detected the expression of AQP5 (an essential protein in salivary secretion). Global gene expression profiling was performed on submandibular gland tissue of extracted NOD mice model using RNA-seq. Subsequently, a series of bioinformatics analyses of transcriptome sequencing was performed, including differentially expressed genes (DEGs) identification, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, PPI network construction, hub gene identification, and the validity of diagnostic indicators using the dataset GSE40611. Finally, IFN-γ was used to treat the cells, the submandibular gland tissue of NOD mice model was extracted, and RT-qPCR was applied to verify the expression of hub genes. RESULTS: We found that NOD mice model had reduced salivary secretion and increased water consumption. H&E staining suggests acinar destruction and basement membrane changes in glandular tissue. Immunohistochemistry detects a decrease in AQP5 immunostaining within acinar. In transcriptome sequencing, 42 overlapping DEGs were identified, and hub genes (REN, A2M, SNCA, KLK3, TTR, and AZGP1) were identified as initiating targets for insulin signaling. In addition, insulin signaling and cAMP signaling are potential pathways for regulating salivary secretion and constructing a regulatory relationship between target-cAMP signaling-salivary secretion. CONCLUSION: The new potential targets and signal axes for regulating salivary secretion provide a strategy for SS therapy in a clinical setting.

12.
Micromachines (Basel) ; 13(10)2022 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-36295973

RESUMO

Currently, many microchips must rely on an external force (such as syringe pump, electro-hydrodynamic pump, and peristaltic pump, etc.) to control the solution in the microchannels, which probably adds manual operating errors, affects the accuracy of fluid manipulation, and enlarges the noise of signal. In addition, the reasonable integration of micropump and microchip remain the stumbling block for the commercialization of microfluidic technique. To solve those two problems, we designed and fabricated a thermal bubble micropump based on MEMS (micro-electro-mechanical systems) technique. Many parameters (voltage, pulse time, cycle delay time, etc.) affecting the performance of this micropump were explored in this work. The experimental results showed the flow rate of solution with the assistance of a micropump reached more than 15 µL/min in the optimal condition. Finally, a method about measuring total aflatoxin in Chinese herbs was successfully developed based on the integrated platform contained competitive immunoassay and our micropump-based microfluidics. Additionally, the limit of detection in quantifying total aflatoxin (AF) was 0.0615 pg/mL in this platform. The data indicate this combined technique of biochemical assays and micropump based microchip have huge potential in automatically, rapidly, and sensitively measuring other low concentration of biochemical samples with small volume.

13.
Bioact Mater ; 15: 288-304, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35356817

RESUMO

While most studies of mechanical stimulation of cells are focused on two-dimensional (2D) and three-dimensional (3D) systems, it is rare to study the effects of cyclic stretching on cells under a quasi-3D microenvironment as a linkage between 2D and 3D. Herein, we report a new method to prepare an elastic membrane with topographic microstructures and integrate the membrane into a microfluidic chip. The fabrication difficulty lay not only in the preparation of microstructures but also in the alignment and bonding of the patterned membrane to other layers. To resolve the problem, we designed and assembled a fast aligner that is cost-effective and convenient to operate. To enable quasi-3D microenvironment of cells, we fabricated polydimethylsiloxane (PDMS) microwell arrays (formed by micropillars of a few microns in diameter) with the microwell diameters close to the cell sizes. An appropriate plasma treatment was found to afford a coating-free approach to enable cell adhesion on PDMS. We examined three types of cells in 2D, quasi-3D, and 3D microenvironments; the cell adhesion results showed that quasi-3D cells behaved between 2D and 3D cells. We also constructed transgenic human mesenchymal stem cells (hMSCs); under cyclic stretching, the visualizable live hMSCs in microwells were found to orientate differently from in a 3D Matrigel matrix and migrate differently from on a 2D flat plate. This study not only provides valuable tools for microfabrication of a microfluidic device for cell studies, but also inspires further studies of the topological effects of biomaterials on cells.

14.
Front Pharmacol ; 13: 818116, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35264956

RESUMO

Xerostomia is a common symptom in menopausal women, suggesting the role of sex steroids in disease development. Shreds of literature had reported the potential use of herbal extracts to relieve xerostomia. However, a cocktail of multiple components in herbal extract makes it difficult to understand the exact mechanism of action. Aquaporin5 (AQP5), the specific aquaporin expressed in salivary glands, plays an important role in salivary secretion as a downstream of estrogen signaling. In this study, we aimed to unravel a single active herbal component as a therapeutic for xerostomia and investigate its mechanism of action. The effects of apigenin (flavonoid), dauricine (alkaloids), protopine (alkaloids), and lentinan (polysaccharides) on AQP5 transcription were screened in vitro. Only apigenin robustly induced AQP5 transcription and expression, and this effect was even robust compared to the effect of estradiol (E2, a positive control). Overexpression of estrogen receptor α (ERα) in the human salivary gland cell line (HSG) upregulated the AQP5 transcription and expression and the knockdown ERα reversed this effect, suggesting the role of ERα signaling on AQP5 activation in HSG cells. Docking results showed apigenin-specific binding sites in ERα. We further analyzed the therapeutic effect of apigenin on ovariectomized mice as a xerostomia model. The saliva secretion in the xerostomia group was reduced to one-third of the sham group, whereas the apigenin or E2 treatment for 12 weeks reversed this effect. Meanwhile, the water consumption in the xerostomia group was augmented obviously compared to the sham group, whereas the water consumption in the apigenin and E2 group was declined to the level of the sham group. Immunohistochemistry of submandibular glands revealed the downregulation of AQP5 expression in xerostomia mice compared to control. Apigenin, or E2 treatment, upregulated AQP5 expression in xerostomia mice. In conclusion, apigenin, a single active component of herbal extract, upregulated AQP5 expression in HSG cells via activation of ERα signaling and restored saliva flow rates in OVX mice. These results revealed apigenin as a single active component of herbal extract with the potential to treat xerostomia.

15.
Biomater Sci ; 9(22): 7471-7482, 2021 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-34617528

RESUMO

The rapid proliferation of tumor cells and tortuous vasculature in solid tumors often bring about a hypoxic tumor microenvironment, which renders tumor cells more resistant to many cancer treatments, including radiotherapy. In this study, an injectable and thermosensitive composite hydrogel composed of perfluorooctanoic acid (PFOA) modified monomethoxy poly(ethylene glycol)-poly(D,L-lactide-co-glycolide) (mPEG-PLGA-PFOA) and perfluorooctyl bromide (PFOB) that presented a thermoreversible sol-gel transition upon heating was developed to deliver exogenous oxygen for the relief of tumor hypoxia and enhancement of radiotherapy. The fluorinated modification of copolymers significantly increased the stability of PFOB in the mPEG-PLGA-PFOA aqueous solution owing to the fluorophilic interaction between PFOB and PFOA-modified copolymers. The introduction of PFOB not only efficiently heightened the oxygen loading capacity of the composite hydrogel, but also endowed it with excellent X-ray opacity, allowing the visual observation of the hydrogel via micro-CT imaging. After peritumoral injection of the oxygen-enriched composite hydrogel, the continuous supply of oxygen effectively relieved tumor hypoxia and down-regulated the expression of hypoxia-inducible factor-1α. Profiting from this, the hyposensitivity of tumor cells to radiation was successfully reversed, and the tumor growth in mice was significantly suppressed and the survival of mice was prolonged when combined with multiple X-ray exposure. As a result, the oxygen-enriched composite hydrogel shows a great potential for radiosensitization to improve the radiotherapeutic efficacy.


Assuntos
Hidrogéis , Neoplasias Experimentais/metabolismo , Oxigênio , Animais , Hipóxia Celular , Camundongos , Neoplasias Experimentais/patologia , Polietilenoglicóis , Polímeros , Microambiente Tumoral
16.
Oncol Lett ; 22(2): 631, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34267823

RESUMO

Breast cancer is one of the most frequently diagnosed cancers amongst women; however, there is currently no effective treatment. Natural compounds are considered to contribute to cancer prevention and have a pivotal role in modulating apoptosis. Rosmanol is a phenolic diterpene compound with antioxidant and anti-inflammatory properties. In the present study, the effects of Rosmanol on breast cancer cell proliferation/apoptosis were investigated, and it was demonstrated that it inhibited the proliferation of MCF-7 and MDA-MB 231 cells but did not have a significant effect on normal human breast MCF-10A cells. In addition, the apoptotic process was accelerated by Rosmanol, through mitochondrial pathways and reactive oxygen species (ROS) production caused by DNA damage, which function further demonstrated by the attenuation and addition of the ROS inhibitor, N-acetyl-cysteine. It was also demonstrated that Rosmanol accelerated cell apoptosis, and arrested breast cancer cells in the S phase. Moreover, Rosmanol inhibited proliferation and promoted apoptosis of cancer cells via the inhibition of ERK and STAT3 signals, attributable to the increase in p-p38, the overexpression of protein inhibitor of activated STAT3, and the decrease in PI3K/AKT, ERK and JAK2/STAT3.

17.
ACS Appl Mater Interfaces ; 13(12): 13934-13948, 2021 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-33739805

RESUMO

The ability of cells to sense and respond to mechanical signals from their surrounding microenvironments is one of the key issues in tissue engineering and regeneration, yet a fundamental study of cells with both cell observation and mechanical stimulus is challenging and should be based upon an appropriate microdevice. Herein we designed and fabricated a two-layer microfluidic chip to enable simultaneous observation of live cells and cyclic stretching of an elastic polymer, polydimethylsiloxane (PDMS), with a modified surface for enhanced cell adhesion. Human mesenchymal stem cells (hMSCs) were examined with a series of frequencies from 0.00003 to 2 Hz and varied amplitudes of 2%, 5%, or 10%. The cells with an initial random orientation were confirmed to be reoriented perpendicular to the stretching direction at frequencies greater than a threshold value, which we term critical frequency (fc); additionally, the critical frequency fc was amplitude-dependent. We further introduced the concept of critical stretching rate (Rc) and found that this quantity can unify both frequency and amplitude dependences. The reciprocal value of Rc in this study reads 8.3 min, which is consistent with the turnover time of actin filaments reported in the literature, suggesting that the supramolecular relaxation in the cytoskeleton within a cell might be responsible for the underlying cell mechanotransduction. The theoretical calculation of cell reorientation based on a two-dimensional tensegrity model under uniaxial cyclic stretching is well consistent with our experiments. The above findings provide new insight into the crucial role of critical frequency and critical stretching rate in regulating cells on biomaterials under biomechanical stimuli.


Assuntos
Materiais Biocompatíveis/química , Dimetilpolisiloxanos/química , Dispositivos Lab-On-A-Chip , Células-Tronco Mesenquimais/citologia , Fenômenos Biomecânicos , Adesão Celular , Linhagem Celular , Elasticidade , Elastômeros/química , Desenho de Equipamento , Humanos , Estresse Mecânico
18.
Biofabrication ; 12(4): 045032, 2020 09 30.
Artigo em Inglês | MEDLINE | ID: mdl-32996471

RESUMO

While the microfluidic chips for cell stretching and real-time cell observations have so far been composed of three layers, the present work reports a two-layer one, which is, on the surface, not available due to the 'inherent' difficulty of unstable focusing on cells in the microscopic observation under the stretching operation, etc. Herein, this difficulty was overcome to a large extent, in the case of appropriate device parameters, which were determined based upon finite element analysis and orthogonal experimental design. The novel chip was fabricated and confirmed to work in frequency up to 2 Hz and stretching ratio up to 20%. We further performed uniaxial stretching experiments of human mesenchymal stem cells on an elastic polymer, polydimethylsiloxane, and the cells were found to be highly oriented perpendicular to the stretching direction. The short working distance on this simplified two-layer chip enabled clear observation of microtubules and stress fibers of cells under an optical microscope. We also tested radial stretching and gradient stretching as proofs of concept of the extendibility of this type of chip. Therefore, in spite of being simpler, the two-layer chip suggested in this study exhibited enhanced and versatile functions, and the present work has thus afforded a new methodology of fabrication of microfluidic chips for the study of cells on biomaterials under a mechanical stimulus.


Assuntos
Microfluídica , Materiais Biocompatíveis , Elasticidade , Análise de Elementos Finitos , Humanos , Polímeros , Fibras de Estresse
19.
Mater Sci Eng C Mater Biol Appl ; 116: 111158, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32806272

RESUMO

In stomatology, the promotion of alveolar bone regeneration while preventing the reduction of ridge absorption remains a challenge. In this work, we designed and prepared bio-mimetic polysaccharide hydrogels that are multi-functional in terms of being injectable, promote self-healing, degradable, porous structure, et al. After introducing nano-hydroxyapatite particles, the composite scaffold of hydrogel/hydroxyapatite (GH) stent was obtained. When GH material was injected into the mandibular incisors of rats following tooth extraction, the new bone area was enhanced more than 50%, while the alveolar ridge was promoted in excess of 60% after 4 weeks. What's more, the wound soft tissue was healed within 1 week. Overall, our results indicate that this optimized GH stent has the potential to both maintain dimensional alveolar ridge, as well as to promote soft tissue healing. Moreover, using the hydroxyapatite-containing hydrogel platform has the potential to promote bone and soft tissue regeneration.


Assuntos
Regeneração Óssea , Durapatita , Hidrogéis , Processo Alveolar , Animais , Hidrogéis/farmacologia , Ratos , Extração Dentária , Alvéolo Dental
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