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1.
Bioorg Chem ; 150: 107493, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38870703

RESUMO

2. This research investigates the impact of the EGCG-CSH/n-HA/CMC composite material on bone defect repair, emphasizing its influence on macrophage polarization and osteogenic differentiation of BMSCs. Comprehensive evaluations of the composite's physical and chemical characteristics were performed. BMSC response to the material was tested in vitro for proliferation, migration, and osteogenic potential. An SD rat model was employed for in vivo assessments of bone repair efficacy. Both transcriptional and proteomic analyses were utilized to delineate the mechanisms influencing macrophage behavior and stem cell differentiation. The material maintained excellent structural integrity and significantly promoted BMSC functions critical to bone healing. In vivo results confirmed accelerated bone repair, and molecular analysis highlighted the role of macrophage M2 polarization, particularly through changes in the SIRPA gene and protein expression. EGCG-CSH/n-HA/CMC plays a significant role in enhancing bone repair, with implications for macrophage and BMSC function. Our findings suggest that targeting SIRPA may offer new therapeutic opportunities for bone regeneration.


Assuntos
Catequina , Diferenciação Celular , Macrófagos , Osteogênese , Ratos Sprague-Dawley , Osteogênese/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Macrófagos/citologia , Animais , Catequina/farmacologia , Catequina/análogos & derivados , Catequina/química , Ratos , Estrutura Molecular , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Relação Dose-Resposta a Droga , Relação Estrutura-Atividade , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/metabolismo , Células-Tronco Mesenquimais/citologia
2.
Genes (Basel) ; 14(3)2023 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-36980946

RESUMO

Adipose-derived stem cells (ADSCs) are used in tissue regeneration therapies. The objective of this study is to identify stable reference genes (RGs) for use in gene expression studies in a characterized equine adipose-derived mesenchymal stem cell (EADMSC) differentiation model. ADSCs were differentiated into adipocytes (ADs) or osteoblasts (OBs), and the proteomes from these cells were analyzed by liquid chromatography tandem mass spectrometry. Proteins that were stably expressed in all three cells types were identified, and the mRNA expression stabilities for their corresponding genes were validated by RT-qPCR. PPP6R1, CCDC97, and then either ACTB or EPHA2 demonstrated the most stable mRNA levels. Normalizing target gene Cq data with at least three of these RGs simultaneously, as per MIQE guidelines (PPP6R1 and CCDC97 with either ACTB or EPHA2), resulted in congruent conclusions. FABP5 expression was increased in ADs (5.99 and 8.00 fold, p = 0.00002 and p = 0.0003) and in OBs (5.18 and 5.91 fold, p = 0.0011 and p = 0.0023) relative to ADSCs. RUNX2 expression was slightly higher in ADs relative to ADSCs (1.97 and 2.65 fold, p = 0.04 and p = 0.01), but not in OBs (0.9 and 1.03 fold, p = 0.58 and p = 0.91).


Assuntos
Células-Tronco Mesenquimais , Proteoma , Animais , Cavalos/genética , Proteoma/genética , Proteoma/metabolismo , DNA Polimerase Dirigida por RNA/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Diferenciação Celular/genética , Células-Tronco Mesenquimais/metabolismo , Expressão Gênica , RNA Mensageiro/metabolismo , RNA Polimerases Dirigidas por DNA/metabolismo
3.
J Biomater Appl ; 37(7): 1286-1299, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36537783

RESUMO

Implantation of bone substitutes is the treatment of choice for bone defects exceeding a critical size, when self-healing becomes impossible. The use of 3D printing techniques allows the construction of scaffolds with customized properties. However, there is a lack of suitable materials for bone replacement. In this study, maleic anhydride-grafted poly (lactic acid) (MAPLA) was investigated as a potential compatibilizer agent for 3D-printed polylactic acid (PLA)/hydroxyapatite (HA) composites, in order to enhance the physicochemical and biological properties of the scaffolds. The grafting process was performed by reactive processing in a torque rheometer, with the evaluation of the use of different concentrations of maleic anhydride (MA). The success of the grafting reaction was confirmed by titration of acid groups and spectroscopic analyses, indicating the presence of succinic anhydride groups on the PLA chain. Morphological analysis of the PLA/HA 3D scaffolds, using SEM, revealed that the use of the compatibilizer resulted in a structure free from voids and holes. The compatibilization also increased the degradation process. On the other hand, TGA and DSC analyses revealed that the use of a compatibilizer had little effect on the thermal properties of the composite. Most importantly, the samples with compatibilizer were demonstrated to have a minimal cytotoxic effect on human mesenchymal stem cells (MSCs), promoting the osteogenic differentiation of these cells in a medium without the addition of classical osteogenic factors. Therefore, the grafting of PLA/HA composites improved their physicochemical and biological properties, especially the induction of MSC osteogenic differentiation, demonstrating the potential of these scaffolds for bone tissue replacement.


Assuntos
Células-Tronco Mesenquimais , Osteogênese , Humanos , Durapatita/química , Anidridos Maleicos/química , Engenharia Tecidual/métodos , Poliésteres/química , Diferenciação Celular , Alicerces Teciduais/química
4.
Stem Cells ; 39(5): 650-668, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33529444

RESUMO

Extracellular matrix (ECM) stiffness plays an important role in the decision making process of smooth muscle differentiation of mesenchymal stem cells (MSCs) but the underlying mechanisms are incompletely understood. Here we show that a signaling axis consisting of PINCH-1 and Notch2 is critically involved in mediating the effect of ECM stiffness on smooth muscle differentiation of MSCs. Notch2 level is markedly increased in ECM stiffness-induced smooth muscle differentiation of human placental MSCs. Knockdown of Notch2 from human placental MSCs effectively inhibits ECM stiffness-induced smooth muscle differentiation, whereas overexpression of North intracellular domain (NICD2) is sufficient to drive human placental MSC differentiation toward smooth muscle cells. At the molecular level, Notch2 directly interacts with PINCH-1. The interaction of Notch2 with PINCH-1 is significantly increased in response to ECM stiffness favoring smooth muscle differentiation. Furthermore, depletion of PINCH-1 from human placental MSCs reduces Notch2 level and consequently suppresses ECM stiffness-induced smooth muscle differentiation. Re-expression of PINCH-1, but not that of a Notch2-binding defective PINCH-1 mutant, in PINCH-1 knockdown human placental MSCs restores smooth muscle differentiation. Finally, overexpression of NICD2 is sufficient to override PINCH-1 deficiency-induced defect in smooth muscle differentiation. Our results identify an ECM stiffness-responsive PINCH-1-Notch2 interaction that is critically involved in ECM stiffness-induced smooth muscle differentiation of human placental MSCs.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Matriz Extracelular/genética , Proteínas com Domínio LIM/genética , Músculo Liso/crescimento & desenvolvimento , Receptor Notch2/genética , Diferenciação Celular/genética , Feminino , Regulação da Expressão Gênica no Desenvolvimento/genética , Humanos , Mecanotransdução Celular/genética , Proteínas de Membrana/genética , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Músculo Liso/metabolismo , Placenta/citologia , Placenta/metabolismo , Placentação/genética , Gravidez , Transdução de Sinais/genética
5.
Acta Biomater ; 111: 254-266, 2020 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-32434077

RESUMO

Multiple particle tracking (MPT) microrheology was employed for monitoring the development of extracellular matrix (ECM) mechanical properties in the direct microenvironment of living cells. A customized setup enabled us to overcome current limitations: (i) Continuous measurements were enabled using a cell culture chamber, with this, matrix remodeling by fibroblasts in the heterogeneous environment of macroporous scaffolds was monitored continuously. (ii) Employing tracer laden porous scaffolds for seeding human mesenchymal stem cells (hMSCs), we followed conventional differentiation protocols. Thus, we were, for the first time able to study the massive alterations in ECM elasticity during hMSC differentiation. (iii) MPT measurements in 2D cell cultures were enabled using a long distance objective. Exemplarily, local mechanical properties of the ECM in human umbilical vein endothelial cell (HUVEC) cultures, that naturally form 2D layers, were investigated scaffold-free. Using our advanced setup, we measured local, apparent elastic moduli G0,app in a range between 0.08 and 60 Pa. For fibroblasts grown in collagen-based scaffolds, a continuous decrease of local matrix elasticity resulted during the first 10 hours after seeding. The osteogenic differentiation of hMSC cells cultivated in similar scaffolds, led to an increase of G0,app by 100 %, whereas after adipogenic differentiation it was reduced by 80 %. The local elasticity of ECM that was newly secreted by HUVECs increased significantly upon addition of protease inhibitor and in high glucose conditions even a twofold increase in G0,app was observed. The combination of these advanced methods opens up new avenues for a broad range of investigations regarding cell-matrix interactions and the propagation of ECM mechanical properties in complex biological systems. STATEMENT OF SIGNIFICANCE: Cells sense the elasticity of their environment on a micrometer length scale. For studying the local elasticity of extracellular matrix (ECM) in the direct environment of living cells, we employed an advanced multipleparticle tracking microrheology setup. MPT is based on monitoring the Brownian motion oftracer particles, which is restricted by the surrounding network. Network elasticity can thusbe quantified. Overcoming current limitations, we realized continuous investigations of ECM elasticityduring fibroblast growth. Furthermore, MPT measurements of stem cell ECM showed ECMstiffening during osteogenic differentiation and softening during adipogenic differentiation.Finally, we characterized small amounts of delicate ECM newly secreted in scaffold-freecultures of endothelial cells, that naturally form 2D layers.


Assuntos
Células-Tronco Mesenquimais , Osteogênese , Diferenciação Celular , Microambiente Celular , Matriz Extracelular , Humanos , Alicerces Teciduais
6.
J Biomed Mater Res A ; 108(5): 1064-1076, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-31967393

RESUMO

Electrospun scaffolds are emerging as extracellular matrix (ECM)mimicking structures for tissue engineering thanks to their nanofibrous architecture. For the development of suitable electrospun scaffolds for bone tissue engineering, the addition of inorganic components has been implemented with the aim to confer important bioactivity like osteoinduction, osteointegration, and cell adhesion to the scaffolds. In this context, we propose a tricomponent electrospun scaffold composed of poly(d,l-lactide), gelatin and RKKP glass-ceramics. The bioactive RKKP glass-ceramic system has attracted interest, due to the presence of ions such as La3+ and Ta5+ , which turned out to be valuable as growth supporting agents for bones. In this work, RKKP glass-ceramics were embedded inside the microfibers of electrospun scaffolds and the structural and biological properties were investigated. Our results showed that the glass-ceramic microparticles were uniformly distributed in the fibrous structure of the scaffold. Furthermore, the glass-ceramics promoted biomineralization of the scaffolds and improved cell viability and osteogenic differentiation. The mineralized layer formed on RKKP-containing scaffolds after incubation in simulated body fluid medium has been shown to be hydroxyapatite by Raman spectroscopy and X-ray diffraction. The results on differentiation studies of canine adipose-derived mesenchymal stem cells grown on the electrospun scaffolds suggest that on varying the content of RKKP in the scaffold, it is possible to drive the differentiation toward chondrogenic or osteogenic commitment. The presence of ions, like La3+ and Ta5+ , in the RKKP embedded polymeric composite scaffolds could play a role in supporting cell growth and promoting differentiation.


Assuntos
Cerâmica/química , Gelatina/química , Células-Tronco Mesenquimais/citologia , Poliésteres/química , Alicerces Teciduais/química , Animais , Células Cultivadas , Cães , Nanofibras/química , Osteogênese , Engenharia Tecidual
7.
Mater Sci Eng C Mater Biol Appl ; 105: 110009, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31546356

RESUMO

In the present study, a two-step sintering (TSS) method has been used to improve the mechanical properties, biocompatibility, drug release, and osteogenesis abilities of hardystonite (HT) ceramic scaffolds for tissue engineering and drug delivery applications. The average particle size of HT scaffold is kept lower than 80 nm and is reached higher than 130 nm by using two-step and conventional sintering methods, respectively. The compressive strengths of the prepared nanocrystalline HT scaffolds were found to be significantly higher than those of the micro-structure HT and currently available hydroxyapatite scaffolds. A comparative analysis of cell viability and live/dead staining of human mesenchymal stem cells (hMSCs) in nano- and micro-structured HT scaffolds and their drug release potentiation was carried out. The results showed that the nano-structured HT scaffolds have higher cell viability, biocompatibility and longer-term doxorubicin (DOX) release potential than the micro-structured ones. The results of quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry (IHC) analyses showed that the expression of adhesion and differentiation supporting genes were significantly higher in nano-structured HT scaffolds as compared to the micro-structured ones. The results of qRT-PCR also showed that the mRNA expression level of ERK1/2 and P38 MAPK from hMSCs were significantly higher in nano-structured HT scaffolds than the micro-structured ones. These results potentially open new aspects for using nano-structured scaffolds in bone tissue engineering applications.


Assuntos
Materiais Biocompatíveis/química , Cerâmica/química , Temperatura Alta , Engenharia Tecidual/métodos , Alicerces Teciduais/química , Biomarcadores/metabolismo , Adesão Celular/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Força Compressiva , Doxorrubicina/farmacologia , Liberação Controlada de Fármacos , Adesões Focais/efeitos dos fármacos , Adesões Focais/metabolismo , Humanos , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/metabolismo , Nanoestruturas/química , Osteocalcina/metabolismo , Osteonectina/metabolismo , Tamanho da Partícula , Silicatos/química , Fatores de Tempo , Difração de Raios X
8.
Biochem Biophys Res Commun ; 518(1): 141-147, 2019 10 08.
Artigo em Inglês | MEDLINE | ID: mdl-31420163

RESUMO

Transplantation of artificially treated metanephroi or pluripotent stem cell-injected blastocyst-derived whole kidneys will be established in the near future as a useful therapeutic method for renal failure. We have attempted in vivo nephron generation for kidney repair by exploiting cellular interactions via conditioned media (CMs). In a previous report, we showed stimulative cross-talks between vascular endothelial cells (VECs) and tubular epithelial cells (TECs) on cell proliferation and morphological changes, the differentiation of mesenchymal stem cells (MSCs) into TECs by TEC-CM, and nephron generation from TECs or MSCs in rat subcutaneous spaces. In this study adding collecting duct cells (CDCs) and their CM, we demonstrate the suppressive actions of CDC-CM against VECs and TECs, in addition to stimulative cross-talks between VECs and TECs, during the above changes. Furthermore, CDC-CM, similar to TEC-CM, caused differentiation of MSCs into TECs. Thus, we injected CDC-CM-induced MSC-differentiated TECs into rat kidney cortices. The pretreatment of cells in 3-dimensional culture using a small amount of gel complex before implantation triggered the generation of much more nephron-like structures, compared to the implantation of non-pretreated cells. Our method of injecting pretreated TECs into kidney cortices might have applications for repairing dysfunctional kidney tissue.


Assuntos
Diferenciação Celular , Injeções , Córtex Renal/citologia , Túbulos Renais/citologia , Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais/citologia , Animais , Comunicação Celular/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Forma Celular/efeitos dos fármacos , Meios de Cultivo Condicionados/farmacologia , Cães , Células Endoteliais/citologia , Células Endoteliais/efeitos dos fármacos , Humanos , Túbulos Renais Coletores/citologia , Células Madin Darby de Rim Canino , Células-Tronco Mesenquimais/efeitos dos fármacos , Camundongos , Ratos
9.
Acta Biomater ; 70: 110-119, 2018 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-29410241

RESUMO

A cell's insoluble microenvironment has increasingly been shown to exert influence on its function. In particular, matrix stiffness and adhesiveness strongly impact behaviors such as cell spreading and differentiation, but materials that allow for independent control of these parameters within a fibrous, stromal-like microenvironment are very limited. In the current work, we devise a self-assembling peptide (SAP) system that facilitates user-friendly control of matrix stiffness and RGD (Arg-Gly-Asp) concentration within a hydrogel possessing a microarchitecture similar to stromal extracellular matrix. In this system, the RGD-modified SAP sequence KFE-RGD and the scrambled sequence KFE-RDG can be directly swapped for one another to change RGD concentration at a given matrix stiffness and total peptide concentration. Stiffness is controlled by altering total peptide concentration, and the unmodified base peptide KFE-8 can be included to further increase this stiffness range due to its higher modulus. With this tunable system, we demonstrate that human mesenchymal stem cell morphology and differentiation are influenced by both gel stiffness and the presence of functional cell binding sites in 3D culture. Specifically, cells 24 hours after encapsulation were only able to spread out in stiffer matrices containing KFE-RGD. Upon addition of soluble adipogenic factors, soft gels facilitated the greatest adipogenesis as determined by the presence of lipid vacuoles and PPARγ-2 expression, while increasing KFE-RGD concentration at a given stiffness had a negative effect on adipogenesis. This three-component hydrogel system thus allows for systematic investigation of matrix stiffness and RGD concentration on cell behavior within a fibrous, three-dimensional matrix. STATEMENT OF SIGNIFICANCE: Physical cues from a cell's surrounding environment-such as the density of cell binding sites and the stiffness of the surrounding material-are increasingly being recognized as key regulators of cell function. Currently, most synthetic biomaterials used to independently tune these parameters lack the fibrous structure characteristic of stromal extracellular matrix, which can be important to cells naturally residing within stromal tissues. In this manuscript, we describe a 3D hydrogel encapsulation system that provides user-friendly control over matrix stiffness and binding site concentration within the context of a stromal-like microarchitecture. Binding site concentration and gel stiffness both influenced cell spreading and differentiation, highlighting the utility of this system to study the independent effects of these material properties on cell function.


Assuntos
Adipogenia , Matriz Extracelular/química , Hidrogéis/química , Células-Tronco Mesenquimais/metabolismo , Oligopeptídeos/química , Linhagem Celular , Humanos , Células-Tronco Mesenquimais/citologia , Porosidade
10.
Adv Healthc Mater ; 6(7)2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28218474

RESUMO

Graphene-based materials (GBMs) have displayed tremendous promise for use as neurointerfacial substrates as they enable favorable adhesion, growth, proliferation, spreading, and migration of immobilized cells. This study reports the first case of the differentiation of mesenchymal stem cells (MSCs) into Schwann cell (SC)-like phenotypes through the application of electrical stimuli from a graphene-based electrode. Electrical differentiation of MSCs into SC-like phenotypes is carried out on a flexible, inkjet-printed graphene interdigitated electrode (IDE) circuit that is made highly conductive (sheet resistance < 1 kΩ/sq) via a postprint pulse-laser annealing process. MSCs immobilized on the graphene printed IDEs and electrically stimulated/treated (etMSCs) display significant enhanced cellular differentiation and paracrine activity above conventional chemical treatment strategies [≈85% of the etMSCs differentiated into SC-like phenotypes with ≈80 ng mL-1 of nerve growth factor (NGF) secretion vs. 75% and ≈55 ng mL-1 for chemically treated MSCs (ctMSCs)]. These results help pave the way for in vivo peripheral nerve regeneration where the flexible graphene electrodes could conform to the injury site and provide intimate electrical simulation for nerve cell regrowth.


Assuntos
Diferenciação Celular , Grafite/química , Células-Tronco Mesenquimais/metabolismo , Células de Schwann/metabolismo , Animais , Estimulação Elétrica , Células-Tronco Mesenquimais/citologia , Ratos , Células de Schwann/citologia
11.
Artigo em Inglês | MEDLINE | ID: mdl-27695438

RESUMO

Elevated bone marrow adiposity (BMA) is defined as an increase in the proportion of the bone marrow (BM) cavity volume occupied by adipocytes. This can be caused by an increase in the size and/or number of adipocytes. BMA increases with age in a bone-site-specific manner. This increase may be linked to certain pathophysiological situations. Osteoporosis or compromised bone quality is frequently associated with high BMA. The involvement of BM adipocytes in bone loss may be due to commitment of mesenchymal stem cells to the adipogenic pathway rather than the osteogenic pathway. However, adipocytes may also act on their microenvironment by secreting factors with harmful effects for the bone health. Here, we review evidence that in a context of energy deficit (such as anorexia nervosa (AN) and restriction rodent models) bone alterations can occur in the absence of an increase in BMA. In severe cases, bone alterations are even associated with gelatinous BM transformation. The relationship between BMA and energy deficit and the potential regulators of this adiposity in this context are also discussed. On the basis of clinical studies and preliminary results on animal model, we propose that competition between differentiation into osteoblasts and differentiation into adipocytes might trigger bone loss at least in moderate-to-severe AN and in some calorie restriction models. Finally, some of the main questions resulting from this hypothesis are discussed.

12.
J Biomed Mater Res A ; 104(9): 2356-68, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27163888

RESUMO

Much is unknown about the effects of culture dimensionality on cell behavior due to the lack of biomimetic substrates that are suitable for directly comparing cells grown on two-dimensional (2D) and encapsulated within three-dimensional (3D) matrices of the same stiffness and biochemistry. To overcome this limitation, we used a self-assembling peptide hydrogel system that has tunable stiffness and cell-binding site density as well as a fibrous microarchitecture resembling the structure of collagen. We investigated the effect of culture dimensionality on human mesenchymal stem cell differentiation at different values of matrix stiffness (G' = 0.25, 1.25, 5, and 10 kPa) and a constant RGD (Arg-Gly-Asp) binding site concentration. In the presence of the same soluble induction factors, culture on top of stiff gels facilitated the most efficient osteogenesis, while encapsulation within the same stiff gels resulted in a switch to predominantly terminal chondrogenesis. Adipogenesis dominated at soft conditions, and 3D culture induced better adipogenic differentiation than 2D culture at a given stiffness. Interestingly, initial matrix-induced cell morphology was predictive of these end phenotypes. Furthermore, optimal culture conditions corresponded to each cell type's natural niche within the body, highlighting the importance of incorporating native matrix dimensionality and stiffness into tissue engineering strategies. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2356-2368, 2016.


Assuntos
Diferenciação Celular , Condrogênese , Hidrogéis/química , Células-Tronco Mesenquimais/metabolismo , Oligopeptídeos/química , Osteogênese , Técnicas de Cultura de Células/métodos , Linhagem Celular , Humanos , Células-Tronco Mesenquimais/citologia
13.
Ann Biomed Eng ; 44(6): 1894-907, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-26935924

RESUMO

Due to the lack of cell-adhesive moieties in traditional synthetic hydrogels, the present work investigated the use of degradable gelatin microparticles (GMPs) as temporary adherent substrates for anchorage-dependent mesenchymal stem cells (MSCs). MSCs were seeded onto GMPs of varying crosslinking densities and sizes to investigate their role on influencing MSC differentiation and aggregation. The MSC-seeded GMPs were then encapsulated in poly(ethylene glycol)-based hydrogels and cultured in serum-free, growth factor-free osteochondral medium. Non-seeded MSCs co-encapsulated with GMPs in the hydrogels were used as a control for comparison. Over the course of 35 days, MSCs seeded on GMPs exhibited more cell-cell contacts, greater chondrogenic potential, and a down-regulation of osteogenic markers compared to the controls. Although the factors of GMP crosslinking and size had nominal influence on MSC differentiation and aggregation, GMPs demonstrate potential as an adherent-substrate for improving cell delivery from hydrogel scaffolds by facilitating cell-cell contacts and improving MSC differentiation.


Assuntos
Antígenos de Diferenciação/biossíntese , Diferenciação Celular , Condrogênese , Gelatina/química , Hidrogéis/química , Células-Tronco Mesenquimais/metabolismo , Animais , Células Cultivadas , Células-Tronco Mesenquimais/citologia , Polietilenoglicóis/química , Coelhos
14.
J Plast Reconstr Aesthet Surg ; 69(2): e19-26, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26725979

RESUMO

Distraction osteogenesis (DO) is a widely used technique in plastic and orthopaedic surgery. During the process, mechanical force is applied to fractured bone to enhance the regenerative processes and induce new bone formation. Although there is an abundance of literature on the clinical process of DO, there is a distinct lack of focus on the underlying biological principles governing this process. DO follows the basic premises of tissue engineering. The mechanical stress stimulates mesenchymal stem cell differentiation down an osteoblastic lineage on a matrix background. The aim of this review is to give an overview of the current knowledge of the molecular mechanism governing this process.


Assuntos
Reatores Biológicos , Regeneração Óssea , Osteogênese por Distração/métodos , Osteogênese/fisiologia , Engenharia Tecidual/instrumentação , Humanos
15.
Australas Phys Eng Sci Med ; 39(1): 123-33, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26634603

RESUMO

Interfragmentary movement (IFM) at the fracture site plays an important role in fracture healing, particularly during its early stage, via influencing the mechanical microenvironment of mesenchymal stem cells within the fracture callus. However, the effect of changes in IFM resulting from the changes in the configuration of locking plate fixation on cell differentiation has not yet been fully understood. In this study, mechanical experiments on surrogate tibia specimens, manufactured from specially formulated polyurethane, were conducted to investigate changes in IFM of fractures under various locking plate fixation configurations and loading magnitudes. The effect of the observed IFM on callus cell differentiation was then further studied using computational simulation. We found that during the early stage, cell differentiation in the fracture callus is highly influenced by fracture gap size and IFM, which in turn, is highly sensitive to locking plate fixation configuration. The computational model predicted that a small gap size (e.g. 1 mm) under a relatively flexible configuration of locking plate fixation (larger bone-plate distances and working lengths) could experience excessive strain and fluid flow within the fracture site, resulting in excessive fibrous tissue differentiation and delayed healing. By contrast, a relatively flexible configuration of locking plate fixation was predicted to improve cartilaginous callus formation and bone healing for a relatively larger gap size (e.g. 3 mm). If further confirmed by animal and human studies, the research outcome of this paper may have implications for orthopaedic surgeons in optimising the application of locking plate fixations for fractures in clinical practice.


Assuntos
Placas Ósseas , Diferenciação Celular , Fixação de Fratura , Consolidação da Fratura , Movimento , Simulação por Computador , Humanos , Teste de Materiais
16.
Mol Oncol ; 8(7): 1306-25, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24917244

RESUMO

Despite the advancements in the cancer therapeutics, gastric cancer ranks as the second most common cancers with high global mortality rate. Integrative functional genomic investigation is a powerful approach to understand the major dysregulations and to identify the potential targets toward the development of targeted therapeutics for various cancers. Intestinal and diffuse type gastric tumors remain the major subtypes and the molecular determinants and drivers of these distinct subtypes remain unidentified. In this investigation, by exploring the network of gene coexpression association in gastric tumors, mRNA expressions of 20,318 genes across 200 gastric tumors were categorized into 21 modules. The genes and the hub genes of the modules show gastric cancer subtype specific expression. The expression patterns of the modules were correlated with intestinal and diffuse subtypes as well as with the differentiation status of gastric tumors. Among these, G1 module has been identified as a major driving force of diffuse type gastric tumors with the features of (i) enriched mesenchymal, mesenchymal stem cell like, and mesenchymal derived multiple lineages, (ii) elevated OCT1 mediated transcription, (iii) involvement of Notch activation, and (iv) reduced polycomb mediated epigenetic repression. G13 module has been identified as key factor in intestinal type gastric tumors and found to have the characteristic features of (i) involvement of embryonic stem cell like properties, (ii) Wnt, MYC and E2F mediated transcription programs, and (iii) involvement of polycomb mediated repression. Thus the differential transcription programs, differential epigenetic regulation and varying stem cell features involved in two major subtypes of gastric cancer were delineated by exploring the gene coexpression network. The identified subtype specific dysregulations could be optimally employed in developing subtype specific therapeutic targeting strategies for gastric cancer.


Assuntos
Regulação Neoplásica da Expressão Gênica , Redes Reguladoras de Genes , Células-Tronco Neoplásicas/patologia , Neoplasias Gástricas/genética , Estômago/patologia , Diferenciação Celular , Linhagem Celular Tumoral , Epigênese Genética , Mucosa Gástrica/metabolismo , Humanos , Células-Tronco Neoplásicas/citologia , Células-Tronco Neoplásicas/metabolismo , Neoplasias Gástricas/patologia
17.
Biol Open ; 1(11): 1058-68, 2012 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-23213385

RESUMO

It has previously been demonstrated that cell shape can influence commitment of human bone marrow-derived mesenchymal stem cells (hBMCs) to adipogenic, osteogenic, chondrogenic, and other lineages. Human periosteum-derived cells (hPDCs) exhibit multipotency similar to hBMCs, but hPDCs may offer enhanced potential for osteogenesis and chondrogenesis given their apparent endogenous role in bone and cartilage repair in vivo. Here, we examined whether hPDC differentiation is regulated by adhesive and mechanical cues comparable to that reported for hBMC differentiation. When cultured in the appropriate induction media, hPDCs at high cell seeding density demonstrated enhanced levels of adipogenic or chondrogenic markers as compared with hPDCs at low cell seeding density. Cell seeding density correlated inversely with projected area of cell spreading, and directly limiting cell spreading with micropatterned substrates promoted adipogenesis or chondrogenesis while substrates promoting cell spreading supported osteogenesis. Interestingly, cell seeding density influenced differentiation through both changes in cell shape and non-shape-mediated effects: density-dependent adipogenesis and chondrogenesis were regulated primarily by cell shape whereas non-shape effects strongly influenced osteogenic potential. Inhibition of cytoskeletal contractility by adding the Rho kinase inhibitor Y27632 further enhanced adipogenic differentiation and discouraged osteogenic differentiation of hPDCs. Together, our results suggest that multipotent lineage decisions of hPDCs are impacted by cell adhesive and mechanical cues, though to different extents than hBMCs. Thus, future studies of hPDCs and other primary stem cell populations with clinical potential should consider varying biophysical metrics for more thorough optimization of stem cell differentiation.

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