Mineralization Of Mesenchymal Stem Cells Research Articles

Comparative effects of calcitriol and calcimimetic on bone health in renal insufficiency

AbstractCalcitriol and calcimimetics are used to treat hyperparathyroidism secondary to chronic kidney disease (CKD). Calcitriol administration and the subsequent increase in serum calcium concentration decrease parathyroid hormone (PTH) levels, which should reduce bone remodeling. We have previously reported that, when maintaining a given concentration of PTH, the addition of calcimimetics is associated with an increased bone cell activity. Whether calcitriol administration affects bone cell activity while PTH is maintained constant should be evaluated in an animal model of renal osteodystrophy. The aim of the present study was to compare in CKD PTH‐clamped rats the bone effects of calcitriol and calcimimetic administration. The results show that the administration of calcitriol and calcimimetic at doses that induced a similar reduction in PTH secretion produced dissimilar effects on osteoblast activity in 5/6 nephrectomized (Nx) rats with secondary hyperparathyroidism and in Nx rats with clamped PTH. Remarkably, in both rat models, the administration of calcitriol decreased osteoblastic activity, whereas calcimimetic increased bone cell activity. In vitro, calcitriol supplementation inhibited nuclear translocation of β‐catenin and reduced proliferation, osteogenesis, and mineralization in mesenchymal stem cells differentiated into osteoblasts. In conclusion, besides the action of calcitriol and calcimimetics at parathyroid level, these treatments have specific effects on bone cells that are independent of the PTH level.

Sustained delivery of IL-10 by self-assembling peptide hydrogel to reprogram macrophages and promote diabetic alveolar bone defect healing.

Delayed regeneration of alveolar bone defects because of prolonged inflammation under diabetic conditions remains a challenge for dental rehabilitation in clinic, and effective therapies are required. Cytokines-based immuotherapies might be a potential strategy to regulate inflammation and bone regeneration. Here, we report that local delivery of interleukin-10 (IL-10) by injectable self-assembling peptide (SAP) hydrogel is efficient to promote proinflammatory (M1)-to-anti-inflammatory (M2) phenotype conversion, thereby enhancing bone regeneration in diabetic alveolar bone defects. Characteristics of SAP hydrogel were evaluated by morphology, injectable and rheological properties. The loading and release of IL-10 from the SAP hydrogel were evaluated over time in culture. The local inflammatory response and bone repair efficacy of the SAP/IL-10 hydrogel was evaluated in vivo using an alveolar bone defect model of diabetic mice. Finally, the direct effects of M2 macrophage on M1 phenotype and mineralization of MSCs were investigated. In vitro, encapsulated IL-10 could be sustainedly released by SAP hydrogel with preserved bioactivities. In vivo, SAP/IL-10 hydrogel showed significantly higher efficacy to attenuate M1 polarization and proinflammatory factors levels, and enhance expressions of osteogenic factors. As a result, diabetic bone regeneration induced by SAP/IL-10 hydrogel was significantly faster. Mechanistically, M2 macrophages induced by sustained IL-10 delivery might promote diabetic bone regeneration by reprogramming M1 phenotype, suppressing local inflammation and enhancing the osteogenic differentiation of mesenchymal stem cells (MSCs). This study highlights that the SAP hydrogel is a promising drug delivery platform for treatment of alveolar bone defects, which might have translational potential in future clinical applications.

Ethyl caffeate inhibits macrophage polarization via SIRT1/NF-κB to attenuate traumatic heterotopic ossification in mice

Heterotopic ossification (HO) denotes the presence of mature bone tissue in soft tissues or around joints. Inflammation is a key driver of traumatic HO, and macrophages play an important role in this process. Ethyl caffeate (ECF), a critical active compound found in Petunia, exerts significant anti-inflammatory effects. Herein, we established a mouse model of HO by transection of the Achilles tendon and back burn and found abundant macrophage infiltration in the early stage of HO, which decreased with time. In vitro and in vivo experiments indicated that ECF inhibited macrophage polarization, and mechanistic studies showed that it inhibited the SIRT1/NF-κB signalling pathway, thereby suppressing the release of downstream inflammatory cytokines. ECF reduced HO in mice, and its effect was comparable to indomethacin (INDO). In vitro studies revealed that ECF did not directly affect the mineralization of mesenchymal stem cells (MSCs) or osteogenic differentiation but inhibited these processes by reducing the level of inflammatory cytokines in the conditioned medium (CM). Thus, M1 macrophages may play a crucial role in the pathogenesis of HO, and ECF is a prospective candidate for the prevention of trauma-induced HO. Data availabilityData will be made available on request

Propofol mediates bone metastasis by regulating PC-derived exosomal miR-142-3p

In this study we investigated the role of propofol in mediating prostate cancer (PCa) bone metastasis through regulating exosomal factors derived from PCa. We isolated exosomes from PCa cells and co-cultured them with mesenchymal stem cells (MSCs). PCa-derived exosomes increased calcium deposition of MSCs and upregulated ALPL'Alkaline phosphatase, tissue-nonspecific isozyme) and BGLAP (Bone Gamma-Carboxyglutamate Protein) expression. Propofol treatment reduced alkaline phosphatase (ALP) activity, and ALPL and BGLAP expression that was induced by PCa-derived exosomes in MSCs. miRNAs present in cancer cell-derived exosomes increased osteogenesis in these cells. We evaluated miRNA expression in PCa cells after treatment with propofol, and found that miR-142-3p was upregulated in PCa cells. Furthermore, we transfected MSCs with miR-142-3p mimics or inhibitors and revealed that miR-142-3p mimics reduced calcium deposition and downregulated ALP activity, and ALPL and BGLAP levels, while miR-142-3p inhibitors increased calcium deposition and increased ALP activity, and ALPL and BGLAP levels. Finally, we determined that MSCs co-cultured with PCa-derived exosomes and transfected with miR-142-3p mimic exhibited reduced calcium deposition and lower ALP activity, and expression of ALPL and BGLAP. These data demonstrate that propofol inhibits osteogenic differentiation and mineralization of MSCs induced by PCa-derived exosomes by regulation of miR-142-3p levels.

Effect of mussel-inspired polydopamine on the reinforced properties of 3D printed β-tricalcium phosphate/polycaprolactone scaffolds for bone regeneration.

Bioceramic/polymer scaffolds have been considered as potential grafts used for facilitating bone healing. Unfortunately, the poor interfacial interaction between polymer matrices and bioceramic fillers limited their use in practical medicine. Thus, a facile strategy for reinforcing the three-dimensional printed β-tricalcium phosphate/polycaprolactone scaffolds through employing polydopamine modified-ceramics as fillers. The effects of the dopamine precursor on the compressive strength, degradability, cell proliferation, osteogenic differentiation, and in vivo osteogenicity were measured. The results indicated that the concentration of dopamine could remarkably affect the thickness and density of the polydopamine layer on fillers, further varying the compressive strength (1.23-fold to 1.64-fold), degradability, and osteogenicity of the scaffolds. More importantly, the presence of polydopamine in the three-dimensional printed composite scaffolds not only facilitated the proliferation, alkaline phosphatase activity and mineralization of mesenchymal stem cells, but also stimulated the formation of neo-bone tissue in femur defects. Taking together, the proposed scaffolds might serve as a candidate for bone regeneration.

Osteoclast-derived small extracellular vesicles induce osteogenic differentiation via inhibiting ARHGAP1

Activated osteoclasts release large amounts of small extracellular vesicles (sEVs) during bone remodeling. However, little is known about whether osteoclast-derived sEVs affect surrounding cells. In this study, osteoclasts were generated by stimulating bone marrow macrophages (BMMs) with macrophage colony stimulating factor (M-CSF) and receptor activator of nuclear actor κB ligand (RANKL). We performed microarray analysis of sEV-microRNAs (miRNAs)s secreted from osteoclast at different stages and identified four miRNAs that were highly expressed in mature osteoclast-derived sEVs. One of these miRNAs, miR-324, significantly induced osteogenic differentiation and mineralization of primary mesenchymal stem cells (MSCs) in vitro by targeting ARHGAP1, a negative regulator of osteogenic differentiation. We next fabricated an sEV-modified scaffold by coating decalcified bone matrix (DBM) with osteoclast-derived sEVs, and the pro-osteogenic regeneration activities of the sEV-modified scaffold were validated in a mouse calvarial defect model. Notably, miR-324-enriched sEV-modified scaffold showed the highest capacity on bone regeneration, whereas inhibition of miR-324 in sEVs abrogated these effects. Taken together, our findings suggest that miR-324-contained sEVs released from mature osteoclast play an essential role in the regulation of osteogenic differentiation and potentially bridge the coupling between osteoclasts and MSCs.

Synergy of molecularly mobile polyrotaxane surfaces with endothelial cell co-culture for mesenchymal stem cell mineralization.

Stem cell-based bone tissue engineering is a promising strategy for the treatment of bone defects. Since regeneration of bone tissue takes a long time, promoting osteogenesis of stem cells is desired for earlier recovery from dysfunctions caused by bone defects. Here, we combined endothelial cell co-culture using the molecularly mobile sulfonated polyrotaxane (PRX) surfaces to enhance the mineralization of human bone marrow derived mesenchymal stem cells (HBMSCs). Sulfonated PRXs are composed of sulfopropyl ether-modified α-cyclodextrins (α-CDs) threaded on a polyethylene glycol chain. The molecular mobility of PRX, α-CDs moving along the polymer, can be modulated by the number of α-CDs. When osteoblastic differentiation was induced in HBMSCs and human umbilical vein endothelial cells (HUVECs), co-culture groups on sulfonated PRX surfaces with low molecular mobility showed the highest mineralization, which is about two times as high as co-culture groups on sulfonated PRX surfaces with high molecular mobility. Nuclear accumulation of yes-associated proteins in HBMSCs and cell–cell communication via cytokines or cadherin may play an important role in synergistically induced mineralization of HBMSCs.

Collagen maturity and mineralization in mesenchymal stem cells cultured on the hydroxyapatite-based bone scaffold analyzed by ATR-FTIR spectroscopic imaging

Modern bone tissue engineering is based on the use of implants in the form of biomaterials, which are used as scaffolds for osteoprogenitor or stem cells. The task of the scaffolds is to temporarily sustain the function, proliferation and differentiation of bone tissue to enable its regeneration. The aim of this work is to use the macro ATR-FTIR spectroscopic imaging for analysis of the ceramic-based biomaterial (chitosan/β-1,3-glucan/hydroxyapatite). Specifically, during long-term culture of mesenchymal cells derived from adipose tissue (ADSCs) and bone marrow (BMDSCs) on the surface of scaffold. Infrared spectroscopy allows the acquisition of information on both the organic and inorganic parts of the tested composite. This innovative spectroscopic approach proved to be very suitable for studying the formation of new bone tissue and ECM components, sample staining and demineralization are not required and consequently the approach is rapid and cost-effective. The novelty of this study focuses on the innovatory use of ATR-FTIR imaging to evaluate the molecular structure and maturity of collagen as well as mineral matrix formation and crystallization in the context of bone regenerative medicine. Our research has shown that the biomaterial investigated on this work facilitates the formation of valid bone ECM of the stem cells types studied, as a result of the synthesis of type I collagen and mineral content deposition. Nevertheless, ADSC cells have been proven to produce a greater amount of collagen with a lower content of helical secondary structures, at the same time showing a higher mineralization intensity compared to BMDSC cells. Considering the above results, it could be stated that the developed scaffold is a promising material for biomedical applications, including modification of bone implants to increase their biocompatibility.

Over-expression of miR-411–5p and miR-434–3p promotes the osteoblast differentiation by targeting GATA4

ObjectiveTo investigate the role of miR-411–5p and miR-434–3p in osteoblast differentiation in particulate-induced osteolysis. MethodsA mouse model of osteolysis and an in vitro osteolysis model were constructed. The expressions of molecules were detected using qRT-PCR and western blot. Alkaline phosphatase (ALP) activity was measured using the ALP Assay Kit, and the bone mineralization was measured using alizarin red staining. ResultsThe expression of miR-411–5p and miR-434–3p was decreased in osteolysis mice and UHMWPE-induced mMSCs, while GATA4 protein expression was increased. Over-expression of miR-411–5p and miR-434–3p up-regulated the expressions of osteoblast gene markers, enhanced the ALP activity, promoted the bone mineralization of mesenchymal stem cells. In addition, miR-411–5p and miR-434–3p could target GATA4, and miR-411–5p/434–3p affected the expressions of osteoblast gene markers through GATA4 in vitro and in vivo. ConclusionOverexpression of miR-411–5p and miR-434–3p promoted the osteoblast differentiation by inhibiting GATA4 expression.

Decellularized pulp matrix as scaffold for mesenchymal stem cell mediated bone regeneration

Scaffolds that are used for bone repair should provide an adequate environment for biomineralization by mesenchymal stem cells (MSCs). Recently, decellularized pulp matrices (DPM) have been utilized in endodontics for their high regenerative potential. Inspired by the dystrophic calcification on the pulp matrix known as pulp stone, we developed acellular pulp bioscaffolds and examined their potential in facilitating MSCs mineralization for bone defect repair. Pulp was decellularized, then retention of its structural integrity was confirmed by histological, mechanical, and biochemical evaluations. MSCs were seeded and proliferation, osteogenic gene expression, and biomineralization were assessed to verify DPM’s osteogenic effects in vitro. MicroCT, energy-dispersive X-ray (EDX), and histological analyses were used to confirm that DPM seeded with MSCs result in greater mineralization on rat critical-sized defects than that without MSCs. Overall, our study proves DPM’s potential to serve as a scaffolding material for MSC-mediated bone regeneration for future craniofacial bone tissue engineering.

Controlled Release of Naringin in GelMA-Incorporated Rutile Nanorod Films to Regulate Osteogenic Differentiation of Mesenchymal Stem Cells.

Naringin, a Chinese herbal medicine, has been demonstrated to concentration-dependently promote osteogenic differentiation of mesenchymal stem cells (MSCs). However, it remains a challenge to load naringin on coatings for osteogenesis and further control the release kinetics. Here, we demonstrated that the release behavior of naringin on rutile nanorod films could be controlled by either mixing naringin with gelatin methacryloyl (GelMA) before spinning onto the films or soaking the obtained GelMA-incorporated films with the naringin solution to achieve the distinct degradation-type release and diffusion-type release, respectively. We further revealed that the naringin-loaded coatings facilitated adhesion, proliferation and late differentiation, and mineralization of MSCs. Our findings provided a novel strategy to engineer the coatings with controlled release of naringin and emphasized the bioactivity of naringin for the osteogenic differentiation of MSCs.

HLA-B27-mediated activation of TNAP phosphatase promotes pathogenic syndesmophyte formation in ankylosing spondylitis.

Ankylosing spondylitis (AS) is a type of axial inflammation. Over time, some patients develop spinal ankylosis and permanent disability; however, current treatment strategies cannot arrest syndesmophyte formation completely. Here, we used mesenchymal stem cells (MSCs) from AS patients (AS MSCs) within the enthesis involved in spinal ankylosis to delineate that the HLA-B27-mediated spliced X-box-binding protein 1 (sXBP1)/retinoic acid receptor-β (RARB)/tissue-nonspecific alkaline phosphatase (TNAP) axis accelerated the mineralization of AS MSCs, which was independent of Runt-related transcription factor 2 (Runx2). An animal model mimicking AS pathological bony appositions was established by implantation of AS MSCs into the lumbar spine of NOD-SCID mice. We found that TNAP inhibitors, including levamisole and pamidronate, inhibited AS MSC mineralization in vitro and blocked bony appositions in vivo. Furthermore, we demonstrated that the serum bone-specific TNAP (BAP) level was a potential prognostic biomarker to predict AS patients with a high risk for radiographic progression. Our study highlights the importance of the HLA-B27-mediated activation of the sXBP1/RARB/TNAP axis in AS syndesmophyte pathogenesis and provides a new strategy for the diagnosis and prevention of radiographic progression of AS.

Hypoxia Influences the Effects of Magnesium Degradation Products on the Interactions between Endothelial and Mesenchymal Stem Cells

Biodegradable materials like well documented Magnesium (Mg) are promising for their biocompatibility and tissue regeneration. Since Mg degradation is reported to be oxygen related, the effects of Mg are hypothesised to be influenced by oxygen. As two vital components of bone marrow, endothelial cells (EC) and mesenchymal stem cells (MSC), their interactions represent high scientific interest for tissue engineering and biodegradable Mg application. Cell proliferation, MSC migration, gene, and cytokines were investigated in MSC-EC coculture using DNA, flow cytometry, wound healing assay, semi-quantitative real time polymerase chain reaction (qRT-PCR), and enzyme-linked immunosorbent assay (ELISA). Mg decreased the MSC proliferation while increased its migration in transwell under hypoxia. Only in contacting coculture, Mg increased MSC/EC ratio. Oxygen tension changed the regulation of Mg on genes like migration and angiogenetic regulators. Under contacting coculture and hypoxia, Mg degradation products remarkably increased cytokines (e.g., c-c motif chemokine ligand 2 and vascular endothelial growth factor) and MSC mineralization. In summary, this work indicates the roles of low oxygen and heterotypic contact to effects of Mg materials facilitating EC and MSC.

Elevated extracellular calcium ions promote proliferation and migration of mesenchymal stem cells via increasing osteopontin expression

Supplementation of mesenchymal stem cells (MSCs) at sites of bone resorption is required for bone homeostasis because of the non-proliferation and short lifespan properties of the osteoblasts. Calcium ions (Ca2+) are released from the bone surfaces during osteoclast-mediated bone resorption. However, how elevated extracellular Ca2+ concentrations would alter MSCs behavior in the proximal sites of bone resorption is largely unknown. In this study, we investigated the effect of extracellular Ca2+ on MSCs phenotype depending on Ca2+ concentrations. We found that the elevated extracellular Ca2+ promoted cell proliferation and matrix mineralization of MSCs. In addition, MSCs induced the expression and secretion of osteopontin (OPN), which enhanced MSCs migration under the elevated extracellular Ca2+ conditions. We developed in vitro osteoclast-mediated bone resorption conditions using mouse calvaria bone slices and demonstrated Ca2+ is released from bone resorption surfaces. We also showed that the MSCs phenotype, including cell proliferation and migration, changed when the cells were treated with a bone resorption-conditioned medium. These findings suggest that the dynamic changes in Ca2+ concentrations in the microenvironments of bone remodeling surfaces modulate MSCs phenotype and thereby contribute to bone regeneration.

Evidence for Lgr6 as a Novel Marker of Osteoblastic Progenitors in Mice.

Bone marrow-derived mesenchymal stem cells are an important source of osteoblasts critical for both bone homeostasis and repair. The ability to isolate, or specifically target, mesenchymal stem cells committed to the osteogenic lineage is necessary for orthopedic translational therapy efforts; however the precise molecular signature of these cells remains elusive. Previously, we identified a population of osteoprogenitor cells expressing the Wnt signaling agonist Lgr6, which contributes to the development and regeneration of the mouse digit tip bone. In our present study we build upon this data and investigate the expression of Lgr6 more broadly in the skeleton. We find that Lgr6, and closely related Lgr4, are expressed in mouse primary calvarial cells, bone marrow cells, and bone marrow-derived mesenchymal stem cells. In addition, our data demonstrates that Lgr4 expression is modestly increased throughout the differentiation and mineralization of mesenchymal stem cells. In contrast, we find Lgr6 expression to be strikingly increased upon osteogenic induction and subsequently decreased upon differentiation and mineralization. These findings provide evidence for Lgr6 as a novel marker of osteoprogenitor cells in bone marrow, which could prove useful for isolation of this population toward future research and clinical applications.

Tricin enhances osteoblastogenesis through the regulation of Wnt/β-catenin signaling in human mesenchymal stem cells

Mesenchymal stem cells (MSCs) are multipotent stromal cells that are capable of differentiate into multilineage cell types including bone in vitro and in vivo. Aim of the study: They have been widely developed as a therapeutic approach for bone tissue repair and regeneration. However, the efficiency of lineage specific differentiation still needs improvement. We investigated the effect of Tricin on the proliferation of human adult MSCs by alamar blue assay, the mineralization of MSCs by staining of calcium deposition, and the expression levels of the osteoblastic marker genes during osteogenic differentiation of MSCs. Moreover, we also checked the effects of Tricin on the expression of key genes in Wnt/β-catenin signaling pathway. We found Tricin could promote proliferation of MSCs, as well as their mineralization. Tricin could also enhance the expression of osteogenesis marker genes including Bone sialoprotein, osteocalcin, Alkaline phosphatase, and RUNX2. Furthermore, we found out that neither siβ-catenin nor GSK-3β had effect on Tricin treatment, but siWnt3α could neutralize the effect of Tricin. Tricin can enhance osteoblastogenesis through the regulation of Wnt/β-catenin signaling pathway in human adult MSCs in vitro.

Isolation, culture and induced differentiation of rabbit mesenchymal stem cells into osteoblasts.

Mesenchymal stem cells (MSCs) may be easily isolated from the bone marrow, and possess multi-lineage differentiation potential and various therapeutic applications. The differentiation of MSCs into osteoblasts is a complex process that is regulated by multiple internal and external factors. In the present study, the differentiation of MSCs isolated from rabbit bone marrow into osteoblasts using different osteoblast inductive media in the presence of dexamethasone, bone morphogenetic protein 2 (BMP-2), 1,25-dihydroxyvitamin D3, transforming growth factor β (TGFβ), platelet lysate and cyclooxygenase 2 (COX2), respectively. Alkaline phosphatase (ALP) activity, mineralization, collagen type (Ct) I and osteocalcin activities, and the mRNA and protein expression levels of vascular endothelial growth factor (VEGF), BMP-2 and Ct II were measured during the differentiation process in MSCs treated with different inducers. Rabbit MSCs were successfully isolated and were observed to be predominantly circular in shape after culture for 24 h. Following subculture for 5 days, the cells demonstrated a spindle shape. ALP, Ct I and osteocalcin activities were higher in cells cultured in dexamethasone, BMP-2 and TGFβ compared with the activities in control cells. Following differentiation, the dexamethasone, BMP-2 and TGFβ groups demonstrated significantly enhanced mineralization of MSCs detected by Alizarin Red S staining. The mRNA and protein expression levels of VEGF, BMP-2 and Ct II were significantly increased in the same groups compared with the levels in the control group. In conclusion, rabbit MSCs were successfully isolated from bone marrow and differentiated into osteoblasts indicated by raised ALP, Ct I and osteocalcin activities, mineralization and expression of osteogenesis-inducing genes and proteins. The present study revealed that dexamethasone, BMP-2 and TGFβ have a positive effect on cell differentiation.

Controlled Release of Naringin in Metal-Organic Framework-Loaded Mineralized Collagen Coating to Simultaneously Enhance Osseointegration and Antibacterial Activity.

Two important goals in orthopedic implant research are to promote osseointegration and prevent infection. However, much previous effort has been focused on the design of coatings to either enhance osseointegration while ignoring antibacterial activity or vice versa, to prevent infection while ignoring bone integration. Here, we designed a multifunctional mineralized collagen coating on titanium with the aid of metal-organic framework (MOF) nanocrystals to control the release of naringin, a Chinese herbal medicine that could promote osseointegration and prevent bacterial infection. The attachment, proliferation, osteogenic differentiation, and mineralization of mesenchymal stem cells on the coating were significantly enhanced. Meanwhile, the antibacterial abilities against Staphylococcus aureus were also promoted. Furthermore, release kinetics analysis indicated that the synergistic effect of a primary burst release stage and secondary slow release stage played a critical role in the performance and could be controlled by the relative concentrations of MOF and naringin. This work thus provides a novel strategy to engineer multifunctional orthopedic coatings that can enhance osseointegration and simultaneously inhibit microbial cell growth.

Osteogenesis and mineralization of mesenchymal stem cells in collagen type I-based recombinant peptide scaffolds.

Recombinant peptides have the power to harness the inherent biocompatibility of natural macromolecules, while maintaining a defined chemistry for use in tissue engineering. Creating scaffolds from peptides requires stabilization via crosslinking, a process known to alter both mechanics and density of adhesion ligands. The chemistry and mechanics of linear scaffolds from a recombinant peptide based on human collagen type I (RCP) was investigated after crosslinking. Three treatments were compared: dehydrothermal treatment (DHT), hexamethylene diisocyanate (HMDIC), and genipin. With crosslinking, mechanical properties were not significantly altered, ranging from 1.9 to 2.7 kPa. However, the chemistry of the scaffolds was changed, affecting properties such as water uptake, and initial adhesion of human mesenchymal stem cells (hMSCs). Genipin crosslinking supported the lowest adhesion, especially during osteoblastic differentiation. While significantly altered, RCP scaffold chemistry did not affect osteoblastic differentiation of hMSCs. After four weeks in vitro, all scaffolds showed excellent cellular infiltration, with up-regulated osteogenic markers (RUNX2, Osteocalcin, Collagen type I) and mineralization, regardless of the crosslinker. Thus, it appears that, without significant changes to mechanical properties, crosslinking chemistry did not regulate hMSC differentiation on scaffolds from recombinant peptides, a growing class of materials with the ability to expand the horizons of regenerative medicine. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1856-1866, 2017.

Vascular endothelial growth factor-C induces osteogenic differentiation of human mesenchymal stem cells through the ERK and RUNX2 pathway

Vascular endothelial cell growth factor C (VEGF-C) is a member of the VEGF family and plays a role in a variety of biological activities including lymphangiogenesis, angiogenesis, and neurogenesis through VEGF receptor 2 (VEGFR2) and 3 (VEGFR3). However, it has not been elucidated whether VEGF-C promotes osteogenic differentiation. Herein, we investigated the effects of VEGF-C on osteogenic differentiation in human mesenchymal stem cells (MSCs) and evaluated the underlying molecular mechanisms. VEGF-C treatment significantly increased RUNX2 expression, and led to the promotion of osteogenic marker gene expression and mineralization of MSCs. VEGF-C treatment induced the phosphorylation of VEGFR2 and VEGFR3 in MSCs. Treatment with the VEGFR3-specific ligand VEGF-C156S also promoted MSC mineralization. Furthermore, co-treatment with VEGFR2 and VEGFR3 kinase inhibitors blocked VEGF-C-induced MSC mineralization. VEGF-C treatment activated ERK signaling in MSCs, and inhibition of ERK signaling effectively suppressed VEGF-C-induced RUNX2 expression and mineralization. These results indicate that VEGF-C-induced MSC osteogenesis is mediated through VEGFR2 and VEGFR3, and followed the activation of the ERK/RUNX2 signaling pathway.