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1.
J Cell Sci ; 135(5)2022 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-34080635

RESUMO

Despite the recognized significance of reversible protein lipidation (S-acylation) for T cell receptor signal transduction, the enzymatic control of this post-translational modification in T cells remains poorly understood. Here, we demonstrate that DHHC21 (also known as ZDHHC21), a member of the DHHC family of mammalian protein acyltransferases, mediates T cell receptor-induced S-acylation of proximal T cell signaling proteins. Using Zdhhc21dep mice, which express a functionally deficient version of DHHC21, we show that DHHC21 is a Ca2+/calmodulin-dependent enzyme critical for activation of naïve CD4+ T cells in response to T cell receptor stimulation. We find that disruption of the Ca2+/calmodulin-binding domain of DHHC21 does not affect thymic T cell development but prevents differentiation of peripheral CD4+ T cells into Th1, Th2 and Th17 effector T helper lineages. Our findings identify DHHC21 as an essential component of the T cell receptor signaling machinery and define a new role for protein acyltransferases in regulation of T cell-mediated immunity.


Assuntos
Linfócitos T CD4-Positivos , Cálcio , Acetiltransferases , Aciltransferases/genética , Animais , Diferenciação Celular , Camundongos , Receptores de Antígenos de Linfócitos T/genética
2.
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi ; 37(9): 815-820, 2021 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-34533129

RESUMO

Objective To investigate the effect of salvianolic acid B (SalB) on the proliferation, migration and differentiation of human gingival mesenchymal stem cells (hGMSCs). Methods The hGMSCs were isolated and cultured, and the expressions of CD73, CD90, CD34, and CD45 were detected by flow cytometry; logarithmic phase cells were selected and hGMSCs were treated with 0, 5, 10 µmol/L SalB for 24 hours. The proliferation activity of cells in each group was detected by CCK-8 assay, the migration ability of cells was detected by TranswellTM assay and scratch test, and the osteogenic differentiation ability and the adipogenic differentiation ability were detected by alkaline phosphatase (ALP) staining and oil red O staining, respectively; the mRNA and protein expressions of cell differentiation proteins and genes as well as proteins related to the PI3K/AKT signal pathway were detected by Real-time quantiative PCR and Western blotting. Results The proliferation and migration ability of SalB-treated hGMSCs were significantly increased in a dose-dependent manner; the ability of osteogenic differentiation of hGMSCs and the expressions of osteogenesis associated proteins and PI3K/AKT signal pathway related proteins were up-regulated, while the adipogenic differentiation decreased, and the expression of adipogenesis related proteins was significantly down-regulated. Conclusion SalB promotes the proliferation, migration, and osteogenic differentiation of hGMSCs and inhibits the adipogenic differentiation, which may be related to the activation of PI3K/AKT signal pathway.


Assuntos
Células-Tronco Mesenquimais , Osteogênese , Benzofuranos , Diferenciação Celular , Proliferação de Células , Células Cultivadas , Humanos , Fosfatidilinositol 3-Quinases/genética , Proteínas Proto-Oncogênicas c-akt/genética
3.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 56(9): 866-872, 2021 Sep 09.
Artigo em Chinês | MEDLINE | ID: mdl-34496534

RESUMO

Objective: To explore the related mechanisms of biological root resorption in decidual teeth by studying the biological effect of simulated occlusal force on the periodontal ligament stem cells (PDLSC) at different stages of root absorption. Methods: According to the tooth type and root absorption degree, healthy retained deciduous incisors and healthy first premolars that needed to be removed for orthodontic treatment were collected and divided into three groups with six teeth in each group: the deciduous unabsorbed group (UN group), the absorbed group (R group) and the permanent teeth group (P group). PDLSC was isolated from periodontal ligament and cultured. PDLSC of three groups were loaded with dynamic pressure of 0-45, 0-90, 0-135, 0-180, 0-225 and 0-270 kPa, respectively. The proliferation ability was detected by cell counting kit-8 (CCK-8) technique on day 1 to day 7, respectively. The apoptosis levels of PDLSC after loading with dynamic pressure of 0-45, 0-90, 0-135, 0-180 and 0-225 kPa were observed by the flow cytometry. The changes of microfilaments were observed by fibrous actin (F-actin) staining after the cytokeleton was subjected to dynamic pressure of 0-90 kPa. Results: PDLSC of three groups exhibited various proliferation abilities to dynamic pressure. The A values in the UN group and R group were significantly higher than those in the P group and the difference was statistically significant (P<0.05). However, there was no significant difference between the UN group and the R group (P>0.05). The A values of PDLSC in UN group and R group under dynamic pressures of 0-45, 0-90, 0-135 and 0-180 kPa had no statistical significance compared with the control group unloading dynamic pressure (P>0.05). However, under 0-225 and 0-270 kPa dynamic pressures, the A values at the day 3 to day 7 were statistically significant (P<0.05). The A values of PDLSC in P group under 0-45, 0-90, 0-135, 0-180 and 0-225 kPa dynamic pressures for 1 to 7 days were no statistically significant difference compared with the control group (P>0.05). The A value in P group under the 0-270 kPa was statistically significant only on day 3 (1.386±0.131) and day 5 to day 7 (1.728±0.226, 2.029±0.168 and 2.263±0.210, respectively)(P<0.05). The result of apoptosis showed that the A values of PDLSC in UN group, R group and P group were significantly increased under 0-90, 0-135, 0-180 kPa and above dynamic pressures, respectively (P<0.05) compared with the control group unloading dynamic pressure. Under 0-90 kPa dynamic pressure, F-actin fluorescence staining samples in three groups all showed green filaments which were arranged along the long axis of the cells in the R group and the P group, while some fibers in the UN group were closely arranged and promoted stress fiber assembly. Conclusions: The biological characteristics of PDLSC at different root absorption stages were changed when they were stimulated by mechanical stress, and PDLSC of the deciduous teeth at the root unabsorption stage were more sensitive to mechanical stress stimulation.


Assuntos
Força de Mordida , Ligamento Periodontal , Diferenciação Celular , Células-Tronco , Dente Decíduo
4.
World J Gastroenterol ; 27(31): 5259-5271, 2021 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-34497449

RESUMO

BACKGROUND: Various histological types of gastric carcinomas (GCs) differ in terms of their pathogenesis and their preexisting background, both of which could impact the tumor immune microenvironment (TIME). However, the current understanding of the immune contexture of GC is far from complete. AIM: To clarify the tumor-host immune interplay through histopathological features and the tumor immune cycle concept. METHODS: In total, 50 GC cases were examined (15 cases of diffuse GC, 31 patients with intestinal-type GC and 4 cases of mucinous GC). The immunophenotype of GC was assessed and classified as immune desert (ID), immune excluded (IE) or inflamed (Inf) according to CD8+ cell count and spatial pattern. In addition, CD68+ and CD163+ macrophages and programmed death-ligand 1 (PD-L1) expression were estimated. RESULTS: We found that GCs with different histological differentiation demonstrated distinct immune contexture. Most intestinal-type GCs had inflamed TIMEs rich in both CD8+ cells and macrophages. In contrast, more aggressive diffuse-type GC more often possessed ID characteristics with few CD8+ lymphocytes but abundant CD68+ macrophages, while mucinous GC had an IE-TIME with a prevalence of CD68+ macrophages and CD8+ lymphocytes in the peritumor stroma. PD-L1 expression prevailed mostly in intestinal-type Inf-GC, with numerous CD163+ cells observed. Therefore, GCs of different histological patterns have specific mechanisms of immune escape. While intestinal-type GC was more often related to PD-L1 expression, diffuse and mucinous GCs possessing more aggressive behavior demonstrated low immunogenicity and a lack of tumor antigen recognition or immune cell recruitment into the tumor clusters. CONCLUSION: These data help to clarify the links between tumor histogenesis and immunogenicity for a better understanding of GC biology and more tailored patient management.


Assuntos
Carcinoma , Neoplasias Gástricas , Antígeno B7-H1 , Diferenciação Celular , Humanos , Linfócitos do Interstício Tumoral , Microambiente Tumoral
5.
Chin J Dent Res ; 24(3): 143-152, 2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34491008

RESUMO

Tooth eruption is closely linked to the normal development of dentition and proper establishment of occlusion. Disturbances in tooth eruption may affect oral physiological functions, facial contour and aesthetics; it is therefore important to understand the eruption process. This process is a complex biological event involving dynamic changes at the tissue and cellular levels. It is guided by anatomical structures as well as biological and molecular factors that result in the movement of the tooth to its final functional position in the oral cavity. Evidence increasingly suggests that stem cells contribute to tooth development and eruption. Multiple stem cell populations have been discovered in teeth and in their supporting tissues, such as dental follicle precursor cells, orofacial bone-/bone marrow-derived mesenchymal stem cells, periodontal ligament stem cells, stem cells from the apical papilla and dental pulp stem cells. These stem cells exhibit distinct differentiation capacities and are closely linked to alveolar bone remodelling, periodontium development and root formation during the eruption process. The present review summarises the current knowledge of the characteristics and functions of orofacial stem cells in tooth eruption, with a particular focus on recent discoveries concerning their lineage allocation and regulatory mechanisms.


Assuntos
Erupção Dentária , Dente , Diferenciação Celular , Ligamento Periodontal , Células-Tronco
6.
Zhongguo Yi Xue Ke Xue Yuan Xue Bao ; 43(4): 607-611, 2021 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-34494533

RESUMO

There is growing evidence that dermal papilla cells(DPCs)act as the organizing center to induce the cyclic hair regeneration.On one hand,DPCs secrete cytokines or growth factors to regulate the differentiation,proliferation,and migration of epithelial stem cells(EpSCs)and melanocyte stem cells(MeSCs)residing in the bulge region.On the other hand,DPCs manipulate the microenvironment(also termed as niche)for both EpSCs and MeSCs,such as the size of dermal papilla,the distance between dermal papilla and the bulge region,and the lymphatic drainage and sympathetic nerve innervation surrounding the bulge region,thereby orchestrating the cycling hair growth.Recent studies have demonstrated at least four subpopulations existing in dermal papillae,which induce the unilineage transit-amplifying epithelial cells to form the concentric multilayers of hair shafts and sheaths.In addition,emerging study has indicated that sustained psychological stress potentially leads to hyperactivation of the sympathetic nerves that innervate the bulge region.The large amount of norepinephrine released by the nerve endings forces MeSCs to rapidly and abnormally proliferate,resultantly causing the depletion of MeSC pool and the loss of hair pigment.Understanding the molecular regulation of hair growth and pigmentation by DPCs holds substantial promise for the future use of cultured DPCs in vitro to treat hair loss.


Assuntos
Derme , Folículo Piloso , Diferenciação Celular , Células Cultivadas , Pigmentação
7.
Nat Commun ; 12(1): 5220, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34471104

RESUMO

Advancement in human induced pluripotent stem cell (iPSC) neuron and microglial differentiation protocols allow for disease modeling using physiologically relevant cells. However, iPSC differentiation and culturing protocols have posed challenges to maintaining consistency. Here, we generated an automated, consistent, and long-term culturing platform of human iPSC neurons, astrocytes, and microglia. Using this platform we generated a iPSC AD model using human derived cells, which showed signs of Aß plaques, dystrophic neurites around plaques, synapse loss, dendrite retraction, axon fragmentation, phospho-Tau induction, and neuronal cell death in one model. We showed that the human iPSC microglia internalized and compacted Aß to generate and surround the plaques, thereby conferring some neuroprotection. We investigated the mechanism of action of anti-Aß antibodies protection and found that they protected neurons from these pathologies and were most effective before pTau induction. Taken together, these results suggest that this model can facilitate target discovery and drug development efforts.


Assuntos
Doença de Alzheimer/metabolismo , Astrócitos/metabolismo , Células-Tronco Pluripotentes Induzidas/metabolismo , Microglia/metabolismo , Neurônios/metabolismo , Diferenciação Celular , Humanos , Cinética , Placa Amiloide , Sinapses/metabolismo
8.
Nat Commun ; 12(1): 4087, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34471112

RESUMO

We utilized forebrain organoids generated from induced pluripotent stem cells of patients with a syndromic form of Autism Spectrum Disorder (ASD) with a homozygous protein-truncating mutation in CNTNAP2, to study its effects on embryonic cortical development. Patients with this mutation present with clinical characteristics of brain overgrowth. Patient-derived forebrain organoids displayed an increase in volume and total cell number that is driven by increased neural progenitor proliferation. Single-cell RNA sequencing revealed PFC-excitatory neurons to be the key cell types expressing CNTNAP2. Gene ontology analysis of differentially expressed genes (DEgenes) corroborates aberrant cellular proliferation. Moreover, the DEgenes are enriched for ASD-associated genes. The cell-type-specific signature genes of the CNTNAP2-expressing neurons are associated with clinical phenotypes previously described in patients. The organoid overgrowth phenotypes were largely rescued after correction of the mutation using CRISPR-Cas9. This CNTNAP2-organoid model provides opportunity for further mechanistic inquiry and development of new therapeutic strategies for ASD.


Assuntos
Transtorno do Espectro Autista/metabolismo , Proteínas de Membrana/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Organoides/metabolismo , Prosencéfalo/metabolismo , Adolescente , Transtorno do Espectro Autista/genética , Diferenciação Celular , Proliferação de Células , Criança , Feminino , Predisposição Genética para Doença/genética , Humanos , Células-Tronco Pluripotentes Induzidas , Proteínas de Membrana/genética , Mutação , Proteínas do Tecido Nervoso/genética , Neurônios/metabolismo , Fenótipo , Análise de Sequência de RNA
9.
Nat Commun ; 12(1): 5256, 2021 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-34489407

RESUMO

Tissue repair and healing remain among the most complicated processes that occur during postnatal life. Humans and other large organisms heal by forming fibrotic scar tissue with diminished function, while smaller organisms respond with scarless tissue regeneration and functional restoration. Well-established scaling principles reveal that organism size exponentially correlates with peak tissue forces during movement, and evolutionary responses have compensated by strengthening organ-level mechanical properties. How these adaptations may affect tissue injury has not been previously examined in large animals and humans. Here, we show that blocking mechanotransduction signaling through the focal adhesion kinase pathway in large animals significantly accelerates wound healing and enhances regeneration of skin with secondary structures such as hair follicles. In human cells, we demonstrate that mechanical forces shift fibroblasts toward pro-fibrotic phenotypes driven by ERK-YAP activation, leading to myofibroblast differentiation and excessive collagen production. Disruption of mechanical signaling specifically abrogates these responses and instead promotes regenerative fibroblast clusters characterized by AKT-EGR1.


Assuntos
Indóis/farmacologia , Mecanotransdução Celular/fisiologia , Pele/lesões , Sulfonamidas/farmacologia , Cicatrização/fisiologia , Animais , Diferenciação Celular , Células Cultivadas , Colágeno/metabolismo , Feminino , Fibroblastos , Quinase 1 de Adesão Focal/antagonistas & inibidores , Quinase 1 de Adesão Focal/metabolismo , Regeneração Tecidual Guiada , Humanos , Indóis/sangue , Mecanotransdução Celular/efeitos dos fármacos , Análise de Sequência de RNA , Análise de Célula Única , Pele/efeitos dos fármacos , Pele/patologia , Fenômenos Fisiológicos da Pele , Estresse Mecânico , Sulfonamidas/sangue , Suínos , Cicatrização/efeitos dos fármacos
10.
Nat Commun ; 12(1): 5270, 2021 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-34489413

RESUMO

Following injury, cells in regenerative tissues have the ability to regrow. The mechanisms whereby regenerating cells adapt to injury-induced stress conditions and activate the regenerative program remain to be defined. Here, using the mammalian neonatal heart regeneration model, we show that Nrf1, a stress-responsive transcription factor encoded by the Nuclear Factor Erythroid 2 Like 1 (Nfe2l1) gene, is activated in regenerating cardiomyocytes. Genetic deletion of Nrf1 prevented regenerating cardiomyocytes from activating a transcriptional program required for heart regeneration. Conversely, Nrf1 overexpression protected the adult mouse heart from ischemia/reperfusion (I/R) injury. Nrf1 also protected human induced pluripotent stem cell-derived cardiomyocytes from doxorubicin-induced cardiotoxicity and other cardiotoxins. The protective function of Nrf1 is mediated by a dual stress response mechanism involving activation of the proteasome and redox balance. Our findings reveal that the adaptive stress response mechanism mediated by Nrf1 is required for neonatal heart regeneration and confers cardioprotection in the adult heart.


Assuntos
Coração/fisiologia , Traumatismo por Reperfusão Miocárdica/metabolismo , Fator 1 Relacionado a NF-E2/metabolismo , Animais , Animais Recém-Nascidos , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/fisiologia , Doxorrubicina/farmacologia , Feminino , Heme Oxigenase (Desciclizante)/genética , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Células-Tronco Pluripotentes Induzidas/efeitos dos fármacos , Masculino , Camundongos Knockout , Camundongos Transgênicos , Traumatismo por Reperfusão Miocárdica/patologia , Miócitos Cardíacos/fisiologia , Fator 1 Relacionado a NF-E2/genética , Oxirredução , Proteostase , Ratos Sprague-Dawley , Regeneração
11.
Nat Commun ; 12(1): 5255, 2021 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-34489438

RESUMO

Monocytes are part of the mononuclear phagocytic system. Monocytes play a central role during inflammatory conditions and a better understanding of their dynamics might open therapeutic opportunities. In the present study, we focused on the characterization and impact of monocytes on brown adipose tissue (BAT) functions during tissue remodeling. Single-cell RNA sequencing analysis of BAT immune cells uncovered a large diversity in monocyte and macrophage populations. Fate-mapping experiments demonstrated that the BAT macrophage pool requires constant replenishment from monocytes. Using a genetic model of BAT expansion, we found that brown fat monocyte numbers were selectively increased in this scenario. This observation was confirmed using a CCR2-binding radiotracer and positron emission tomography. Importantly, in line with their tissue recruitment, blood monocyte counts were decreased while bone marrow hematopoiesis was not affected. Monocyte depletion prevented brown adipose tissue expansion and altered its architecture. Podoplanin engagement is strictly required for BAT expansion. Together, these data redefine the diversity of immune cells in the BAT and emphasize the role of monocyte recruitment for tissue remodeling.


Assuntos
Tecido Adiposo Marrom/citologia , Monócitos/fisiologia , Adiponectina/genética , Tecido Adiposo Marrom/fisiologia , Animais , Diferenciação Celular/genética , Contagem de Leucócitos , Macrófagos/citologia , Macrófagos/fisiologia , Glicoproteínas de Membrana/metabolismo , Camundongos Transgênicos , Monócitos/citologia , Tomografia por Emissão de Pósitrons , Receptores CCR2/genética , Receptores CCR2/metabolismo
12.
Curr Protoc ; 1(9): e261, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34529356

RESUMO

Machine learning techniques are increasingly becoming incorporated into biological research workflows in a variety of disciplines, most notably cancer research and drug discovery. Efforts in stem cell research comparatively lag behind. We detail key paradigms in machine learning, with a focus on equipping stem cell biologists with the understanding necessary to begin conceptualizing and designing machine learning workflows within their own domain of expertise. Supervised approaches in both regression and classification as well as unsupervised clustering techniques are all covered, with examples from across the biological sciences. High-throughput, high-content, multiplex assays for data acquisition are also discussed in the form of single-cell RNA sequencing and image-based approaches. Lastly, potential applications in stem cell biology, including the development of novel cell types, and improving model maturation are also discussed. Machine learning approaches applied in stem cell biology show promise in accelerating progress in developmental biology, drug screening, disease modeling, and personalized medicine. © 2021 Wiley Periodicals LLC.


Assuntos
Aprendizado de Máquina , Medicina de Precisão , Técnicas de Cultura de Células , Diferenciação Celular , Células-Tronco
13.
Mater Sci Eng C Mater Biol Appl ; 128: 112295, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34474846

RESUMO

It is of great significance to develop osteoinductive artificial scaffold for bone repair and regeneration. We constructed a biomimetic apatite interface on electrospun polycaprolactone fibers by combining layer-by-layer (LbL) nanocoating with mineralization to fabricate an osteoinductive artificial scaffold. After polydopamine modification, cationic type-І collagen and anionic chondroitin sulfate were sequentially adsorbed on the fiber surface. The fibers coated with the multilayer components served as the precursor matrix to induce apatite deposition. By adjusting the number of the layers and duration of mineralization, the nanoscale morphology of composite fibers was optimized. When ten bilayers of the collagen and chondroitin sulfate were deposited onto the fibers followed by one day-mineralization, the obtained polycaprolactone-apatite composite scaffolds significantly promoted the adhesion, proliferation, and osteogenic differentiation of MC3T3-E1 cells. In a subcutaneous implantation in mice, this composite fiber membrane enhanced in vivo ectopic osteogenesis. Our nano-architectural scaffolds were able to mimic the composition and structure of the bone matrix to a certain extent, holding great potential for bone repair and regeneration.


Assuntos
Sulfatos de Condroitina , Osteogênese , Animais , Regeneração Óssea , Diferenciação Celular , Colágeno , Camundongos , Tecidos Suporte
14.
Mater Sci Eng C Mater Biol Appl ; 128: 112306, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34474857

RESUMO

Osteomyelitis is caused by Staphylococcus aureus (S. aureus), with associated progressive bone loss. This study developed for the first time a calcium phosphate cement (CPC) for delivery of doxycycline (DOX) and human platelet lysate (hPL) to fight against S. aureus infection and enhance the osteogenesis of human periodontal ligament stem cells (hPDLSCs). Chitosan-containing CPC scaffolds were fabricated in the absence (CPCC) or presence of DOX (CPCC+DOX). In addition, hPL was encapsulated in alginate microbeads and incorporated into CPCC+DOX (CPCC+DOX+ hPL). Flexural strength of CPCC+DOX + hPL was (5.56 ± 0.55) MPa, lower than (8.26 ± 1.6) MPa of CPCC+DOX (p < 0.05), but exceeding the reported strength of cancellous bone. CPCC+DOX and CPCC+DOX + hPL exhibited strong antibacterial activity against S. aureus, reducing biofilm CFU by 4 orders of magnitude. The hPDLSCs encapsulated in microbeads were co-cultured with the CPCs. The hPDLSCs were able to be released from the microbeads and showed a high proliferation rate, increasing by about 8 folds at 14 days for all groups. The hPL was released from the scaffold and promoted the osteogenic differentiation of hPDLSCs. ALP activity was 28.07 ± 5.15 mU/mg for CPCC+DOX + hPL, higher than 17.36 ± 2.37 mU/mg and 1.34 ± 0.37 mU/mg of CPCC+DOX and CPCC, respectively (p < 0.05). At 7 days, osteogenic genes (ALP, RUNX2, COL-1, and OPN) in CPCC+DOX + hPL were 3-10 folds those of control. The amount of hPDLSC-synthesized bone mineral with CPCC+DOX + hPL was 3.8 folds that of CPCC (p < 0.05). In summary, the novel CPC + DOX + hPL-hPDLSCs scaffold exhibited strong antibacterial activity, excellent cytocompatibility and hPDLSC osteogenic differentiation, showing a promising approach for treatment and prevention of bone infection and enhancement of bone regeneration.


Assuntos
Osteogênese , Ligamento Periodontal , Biofilmes , Fosfatos de Cálcio/farmacologia , Diferenciação Celular , Células Cultivadas , Humanos , Staphylococcus aureus , Células-Tronco
15.
Mater Sci Eng C Mater Biol Appl ; 128: 112309, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34474860

RESUMO

Recently, black phosphorus (BP) has garnered great attention as one of newly emerging two-dimensional nanomaterials. Especially, the degraded platelets of BP in the physiological environment were shown to be nontoxic phosphate anions, which are a component of bone tissue and can be used for mineralization. Here, our study presents the potential of BP as biofunctional and biocompatible nanomaterials for the application to bone tissue engineering and regeneration. An ultrathin layer of BP nanodots (BPNDs) was created on a glass substrate by using a flow-enabled self-assembly process, which yielded a highly uniform deposition of BPNDs in a unique confined geometry. The BPND-coated substrates represented unprecedented favorable topographical microenvironments and supportive matrices suitable for the growth and survival of MC3T3-E1 preosteoblasts. The prepared substrates promoted the spontaneous osteodifferentiation of preosteoblasts, which had been confirmed by determining alkaline phosphatase activity and extracellular calcium deposition as early- and late-stage markers of osteogenic differentiation, respectively. Furthermore, the BPND-coated substrates upregulated the expression of some specific genes (i.e., RUNX2, OCN, OPN, and Vinculin) and proteins, which are closely related to osteogenesis. Conclusively, our BPND-coating strategy suggests that a biologically inert surface can be readily activated as a cell-favorable nanoplatform enabled with excellent biocompatibility and osteogenic ability.


Assuntos
Osteoblastos , Osteogênese , Diferenciação Celular , Fósforo , Engenharia Tecidual
16.
Mater Sci Eng C Mater Biol Appl ; 128: 112315, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34474866

RESUMO

Implant surface plays a crucial role in improving osseointegration and long-term implant life. When the implant comes in contact with the bone tissue, the bone marrow mesenchymal cells interact with the implant surface and the surface properties such as morphology, wettability, mechanical properties and chemistry influences cell migration, proliferation and differentiation. Different surface modification strategies such as ceramic coatings, surface dealloying, and surface topography modifications for improving osteointegration have been investigated. However, studies have not yet established which of the surface property is more influential. In this study, titanium surfaces were treated hydrothermally with sodium hydroxide and sulfuric acid separately. This treatment led to the development of two unique surface topography at nanoscale. These modified surfaces were characterized for surface morphology, wettability, chemistry, and crystallinity. Cytotoxicity, cell adhesion, proliferation, morphology, and differentiation of adipose derived stem cells on modified surfaces was investigated. The results indicate that wettability does influence initial cell adhesion. However, the surface morphology can play major role in cell spreading, proliferation and differentiation. The results indicate that titanium surfaces treated hydrothermally with sodium hydroxide led to a nanoporous architecture that promoted appropriate cell interaction with the surface promoting osteoblastic lineage.


Assuntos
Osteogênese , Titânio , Adesão Celular , Diferenciação Celular , Proliferação de Células , Osseointegração , Osteoblastos , Células-Tronco , Propriedades de Superfície , Titânio/farmacologia
17.
Mater Sci Eng C Mater Biol Appl ; 128: 112325, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34474876

RESUMO

Endogenous microscopic electric cues play an essential role in bone's remodeling and self-repair. Modulating the extracellular electrical environment, by means of external electric stimulation or changing surface potential of implants, was manifested to facilitate the osteointegration. The microscopic potential difference, originating from heterogeneous microstructures of materials, may mimic the endogenous electric signals to stimulate surrounding cells. In this study, the spark-plasma sintered Ti/Ta hybrid metal was fabricated and utilized to realize a surface microscopic potential difference at the same magnitude as endogenous potentials. Activated by the electric stimulation, the mesenchymal stem cells exhibited the anisotropic and polygonal cellular morphology on the Ti/Ta hybrid metal. The microscopic electric potential difference coordinated the cells proliferation on the subsequent days. Moreover, the results showed that the osteo-lineage differentiation on Ti/Ta hybrid metal were in vitro boosted over the control groups. Tailoring microstructures of material to obtain a reasonable electric microenvironment may be a necessary principle to achieve more favorable cell responses to implants, suggesting an extra degree of freedom in bone-repairing material design.


Assuntos
Células-Tronco Mesenquimais , Osteogênese , Diferenciação Celular , Proliferação de Células , Humanos , Titânio
18.
Mater Sci Eng C Mater Biol Appl ; 128: 112347, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34474897

RESUMO

Although the use of bioactive ions and proteins are crucial for bone defect repair, delivering them in a stable and controlled manner remains challenging. To achieve controlled delivery of osteogenic active factor, we developed a novel double network (DN) hydrogel capable of co-delivering Mg2+ ions and BMP2 in a controlled localized manner. This DN hydrogel was composed of poly (acrylamide) and chitosan, in which the poly (acrylamide) was cross-linked via covalent bond and the chitosan was grafted using bisphosphonate (BP) to form metal coordination bonds with Mg2+ ions. Due to this dynamic dissociation and re-association of the "BP-Mg2+" coordination bond, it was possible to deliver Mg2+ ions in a stable and controlled manner. Additionally, the obtained DN hydrogel exhibited an effective tensile strength (0.62 MPa), perfect stretchability (973% fracture strain), and good creep and recovery properties due to the dynamic cross-linking effect of "BP-Mg2+". Additionally, the hydrogel could synergistically promote the proliferation and differentiation of mouse embryo osteoblast precursor cells (MC3T3-E1 cells) in vitro via the BMP2/Wnt pathway. In the skull defect rat model, this positive delivery government of Mg2+ ions and BMP2 synergistically accelerated bone regeneration. In conclusion, this dynamic cross-linked hydrogel containing Mg2+ ions established a new platform for the sustained release of osteogenesis factor and accelerated the bone regeneration process.


Assuntos
Hidrogéis , Magnésio , Animais , Proteína Morfogenética Óssea 2 , Regeneração Óssea , Diferenciação Celular , Íons , Camundongos , Osteogênese , Ratos
19.
Mater Sci Eng C Mater Biol Appl ; 128: 112349, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34474898

RESUMO

Concise, low-cost preparation of titanium alloy implants with high cell proliferation and osteogenic differentiation is urgently needed. Nanosecond laser ablation of titanium alloy has the advantages of short processing time, less pollution, and non-contact. In this research, we adopt a nanosecond UV laser to process the closed groove and cross groove titanium alloys with length to width ratio of 1:1, 2.5:1, 4:1, and 6:1. The surface morphology, surface roughness, phase, element distribution, surface chemistry, and wettability were characterized. The effect of the patterned surface's properties on the adhesion, proliferation, and osteogenic differentiation of stem cells was studied. The results show the laser-ablated lattice structure's surface energy can increase rapidly in the natural environment. The cell adhesion of stem cells on a lattice structure with low roughness and high surface energy is optimal. The element concentration at the ablated edges is higher than at the bottom under Marangoni and surface tension. Stem cells preferentially adhere to the ablated edges with high roughness, element concentration, and hardness. Cell differentiation is chiefly affected by patterning structure. On the surface of the boss structure with a length to width ratio of 2.5:1, the proportion of cell length to diameter is about 2.5, and the cell area is greater. The osteogenic differentiation of cells is the highest on the surface.


Assuntos
Ligas , Titânio , Diferenciação Celular , Proliferação de Células , Lasers , Osteoblastos , Osteogênese , Propriedades de Superfície , Titânio/farmacologia
20.
Mater Sci Eng C Mater Biol Appl ; 128: 112353, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34474901

RESUMO

Cobalt-chromium (CoCr)-based alloys have emerged as an interesting biomaterial within biomedical field, mainly considering their biocompatibility, resistance to corrosion and absence of magnetism; however, its effect on cell metabolism is barely known and this prompted us better evaluating whether CoCr-enriched medium affects the metabolism of both osteoblast and endothelial cells, and also if there is a coupling between them. This is also considered here the already-known effect of Cobalt (Co) as a hypoxic element. Firstly, discs of CoCr [subjecting (W) or not (Wo) to dual acid-etched (DAE)] were incubated into FBS-free cell culture medium up to 24 h (37 °C). This CoCr-enriched medium was further used to treat shear-stressed endothelial cells cultures up to 72 h. Thereafter, the conditioned medium containing metabolites of shear-stressed endothelial cells in response to CoCr-enriched medium was further used to subject osteoblast's cultures, when the samples were properly harvested to allow the analysis of the molecular issues. Our data shows that CoCr-enriched medium contains 1.5 ng-2.0 ng/mL of Co, which was captured by endothelial cells and osteoblasts in about 30% in amount and it seems modulate their metabolic pathways: shear-stressed endothelial cells expressed higher profile of HIF1α, VEGF and nNOS genes, while their global profile of protein carbonylation was lower than the control cultures, suggesting lower oxidative stress commitment. Additionally, osteoblasts responding to metabolites of CoCr-challenged endothelial cells show dynamic expression of marker genes in osteogenic differentiation, with alkaline phosphatase (ALP), osteocalcin, and bone sialoprotein (BSP) genes being significantly increased. Additionally, tensional shear-stress forces decrease the stimulus for ColA1gene expression in osteoblasts responding to endothelial cells metabolites, as well as modifying the extracellular matrix remodeling related genes. Analyzing the activities of matrix metalloproteinases (MMPs), the data shows that shear-stressed endothelial cells metabolites increase the activities of both MMP9 and MMP2 in osteoblasts. Altogether, our data shows for the first time that shear-stressed endothelial metabolites responding to CoCr discs contribute to osteogenic phenotype in vitro, and this predicts an active crosstalk between angiogenesis and osteogenesis during osseointegration of CoCr alloy and bone healing, maybe guided by the Co-induced hypoxic condition.


Assuntos
Cromo , Cobalto , Diferenciação Celular , Cobalto/farmacologia , Meios de Cultivo Condicionados/farmacologia , Células Endoteliais , Osteoblastos , Osteogênese
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