Fusobacterium nucleatum dysregulates inflammatory cytokines and NLRP3 inflammasomes in oral cells.

OBJECTIVE: This study aimed to clarify the difference in Fusobacterium nucleatum (F. nucleatum) induced inflammatory cytokines and nod-like receptor protein 3 (NLRP3) inflammasomes dysregulation among three periodontal cells. METHODS: Oral epithelial cells (HIOECs), THP-1 macrophages, and human gingival fibroblasts (HGFs) were exposed to F. nucleatum with/without adenosine triphosphate (ATP) and nigericin (Nig). Cell morphology was assessed by scanning electron microscopy. qRT-PCR, protein microarrays, and bioinformatic methods were used to evaluate the cytokines and their complex interplay. NLRP3 inflammasomes activation was detected by western blotting and ELISA. RESULTS: F. nucleatum adhered to and invaded cells. In HIOECs, F. nucleatum enhanced interleukin (IL)-1α/1ß/6/10/13, TNF-α, and interferon (IFN)-γ expression. In THP-1 macrophages, F. nucleatum up-regulated IL-1α/1ß/6/10 and TNF-α levels. In HGFs, F. nucleatum increased IL-6 levels. F. nucleatum and ATP synergistically boosted IFN-γ level in THP-1 macrophages and IL-13 level in HGFs. IL-1α/1ß/6, and TNF-α served as epicenters of the inflammatory response. Additionally, F. nucleatum activated NLRP3 inflammasomes in HIOECs, and ATP/Nig boosted the activation. F. nucleatum also triggered NLRP3 inflammasomes in THP-1 macrophages, but in HGFs, only NLRP3 and caspase-1 levels were elevated. CONCLUSION: F. nucleatum infiltrated periodontal supporting cells and dysregulated inflammatory cytokines and NLRP3 inflammasomes.

Neuregulin-1 promotes the proliferation, migration, and angiogenesis of human periodontal ligament stem cells in vitro.

Neuregulin-1 (NRG-1) can promote the proliferation, migration, and angiogenesis of multiple stem cells, as well as prohibit cell apoptosis. In the present study, we aimed to explore the effects of NRG-1 on the proliferation, migration, apoptosis, angiogenic, and osteogenic differentiation of periodontal ligament stem cells (PDLSCs) in vitro. The expression of erythroblastic leukemia viral oncogene homolog 2 (ERBB2), ERBB3, and ERBB4 on PDLSCs were detected by quantitative real-time polymerase chain reaction (qRT-PCR) and immunofluorescence. The effects of NRG-1 on the proliferation, migration, apoptosis, angiogenic and osteogenic differentiation of PDLSCs were assessed by cell proliferation and viability assays, transwell migration assay, flow cytometry assay, tubule formation assay, alkaline phosphatase (ALP) activity, and Alizarin Red S staining, respectively. Gene expression of angiogenesis and osteogenesis-related markers were detected by qRT-PCR. Among the ERBB family members, ERBB2 had the highest expression level in PDLSCs. Further, 10 ng/ml NRG-1 exhibited the maximal effect on proliferation, migration and remarkably inhibited the apoptosis of PDLSCs (p < .05). Moreover, NRG-1 upregulated the expression of vascular endothelial growth factor (VEGF), platelet/endothelial cell adhesion molecule-1 (CD31), hypoxia-inducible factor (HIF), kinase insert domain-containing receptor (KDR) in a dose-dependent manner as well as induced more tube formation. However, NRG-1 did not affect osteogenesis (p > .05). In summary, our study demonstrated that NRG-1 promotes the proliferation, migration, and angiogenesis and inhibits the apoptosis of PDLSCs in vitro and can potentially be used in tissue engineering for periodontal regeneration.

Transcriptome analysis reveals the mechanism of stromal cell-derived factor-1 and exendin-4 synergistically promoted periodontal ligament stem cells osteogenic differentiation.

Stromal cell-derived factor-1 (SDF-1) and Exendin-4 (EX-4) play beneficial roles in promoting periodontal ligament stem cells (PDLSCs) osteogenic differentiation, while the detailed mechanism has not been clarified. In this study, we aimed to evaluate the biological mechanism of SDF-1 and EX-4 alone or synergistic application in regulating PDLSCs differentiation by RNA-sequencing (RNA-seq). A total of 110, 116 and 109 differentially expressed genes (DEGs) were generated in osteogenic medium induced PDLSCs treated by SDF-1, EX-4, and SDF-1+EX-4, respectively. The DEGs in SDF-1 group were enriched in signal transduction related signaling pathways; the DEGs in EX-4 group were enriched in metabolism and biosynthesis-related pathways; and the DEGs generated in SDF-1+EX-4 group were mainly enriched in RNA polymerase II transcription, cell differentiation, chromatin organization, protein phosphorylation pathways. Based on Venn analysis, a total of 37 specific DEGs were identified in SDF-1+EX-4 group, which were mainly enriched in negative regulation of autophagy and cellular component disassembly signaling pathways. Short time-series expression miner (STEM) analysis grouped all expressed genes of PDLSCs into 49 clusters according to the dynamic expression patterns and 25 genes, including NRSN2, CHD9, TUBA1A, distributed in 10 gene clusters in SDF-1+EX-4 treated PDLSCs were significantly up-regulated compared with the SDF-1 and EX-4 alone groups. The gene set enrichment analysis indicated that SDF-1 could amplify the role of EX-4 in regulating varied signaling pathways, such as type II diabetes mellitus and insulin signaling pathways; while EX-4 could aggravate the effect of SDF-1 on PDLSCs biological roles via regulating primary immunodeficiency, tight junction signaling pathways. In summary, our study confirmed that SDF-1 and EX-4 combined application could enhance PDLSCs biological activity and promote PDLSCs osteogenic differentiation by regulating the metabolism, biosynthesis and immune-related signaling pathways.

Stromal cell-derived factor-1/Exendin-4 cotherapy facilitates the proliferation, migration and osteogenic differentiation of human periodontal ligament stem cells in vitro and promotes periodontal bone regeneration in vivo.

OBJECTIVES: Stromal cell-derived factor-1 (SDF-1) actively directs endogenous cell homing. Exendin-4 (EX-4) promotes stem cell osteogenic differentiation. Studies revealed that EX-4 strengthened SDF-1-mediated stem cell migration. However, the effects of SDF-1 and EX-4 on periodontal ligament stem cells (PDLSCs) and bone regeneration have not been investigated. In this study, we aimed to evaluate the effects of SDF-1/EX-4 cotherapy on PDLSCs in vitro and periodontal bone regeneration in vivo. METHODS: Cell-counting kit-8 (CCK8), transwell assay, qRT-PCR and western blot were used to determine the effects and mechanism of SDF-1/EX-4 cotherapy on PDLSCs in vitro. A rat periodontal bone defect model was developed to evaluate the effects of topical application of SDF-1 and systemic injection of EX-4 on endogenous cell recruitment, osteoclastogenesis and bone regeneration in vivo. RESULTS: SDF-1/EX-4 cotherapy had additive effects on PDLSC proliferation, migration, alkaline phosphatase (ALP) activity, mineral deposition and osteogenesis-related gene expression compared to SDF-1 or EX-4 in vitro. Pretreatment with ERK inhibitor U0126 blocked SDF-1/EX-4 cotherapy induced ERK signal activation and PDLSC proliferation. SDF-1/EX-4 cotherapy significantly promoted new bone formation, recruited more CXCR4+ cells and CD90+ /CD34- stromal cells to the defects, enhanced early-stage osteoclastogenesis and osteogenesis-related markers expression in regenerated bone compared to control, SDF-1 or EX-4 in vivo. CONCLUSIONS: SDF-1/EX-4 cotherapy synergistically regulated PDLSC activities, promoted periodontal bone formation, thereby providing a new strategy for periodontal bone regeneration.

[Effects of Exenatide-4 on proliferation, migration and osteogenic differentiation of human periodontal ligament stem cells].

PURPOSE: To investigate the effects of exendin-4(EX-4) on proliferation, migration and osteogenic differentiation of human periodontal ligament stem cells(PDLSCs). METHODS: PDLSCs were isolated and cultured using limited dilution method in vitro. Colony formation assay, osteogenic and adipogenic differentiation were applied to identify the stem cells. Immunofluorescence staining was used to detect the expression of EX-4 receptor glucagon-like peptide-1 receptor (GLP-1R) on the surface of PDLSCs. PDLSCs were stimulated with 5, 10, 20 or 50 nmol/L EX-4 in vitro. CCK-8, Transwell assay and alkaline phosphatase(ALP) activity assay were used to determine the effects of EX-4 on PDLSCs proliferation, migration and osteogenic differentiation. Quantitative real-time polymerase chain reaction was used to determine the expression of osteogenic related genes ALP, runt-related transcription factor 2(Runx2) and osteocalcin (OCN). The data were analyzed by Graphpad Prims 6.0 software package. RESULTS: PDLSCs were successfully isolated and cultivated. GLP-1R positively expressed on the surface of PDLSCs. EX-4 exerted no significant effect on PDLSCs proliferation(P>0.05). EX-4 significantly promoted migration, ALP activity and osteogenic related genes expression of PDLSCs (P<0.05). CONCLUSIONS: 10 nmol/L EX-4 could promote migration and osteogenic differentiation of PDLSCs.

Super-assembled core/shell fibrous frameworks with dual growth factors for in situ cementum-ligament-bone complex regeneration.

The regeneration of periodontal tissue defects remains a clinical challenge due to its complex tissue structure (e.g. periodontal ligament, alveolar bone and cementum) and poor self-healing ability. In situ tissue engineering has emerged as a promising approach that combines frameworks with growth factors that are specifically chosen for the recruitment of endogenous stem cells to the site of injury and to evoke the innate regenerative potential of the body. Herein, a core/shell fibrous super-assembled framework (SAF)-based sequential growth factor delivery system is developed, in which basic fibroblast growth factor (bFGF) and bone morphogenetic protein-2 (BMP-2) are designed to release in a sequential manner to facilitate in situ regeneration of the cementum-ligament-bone complex. The in situ tissue engineering framework (iTE-framework) shows ameliorated physicochemical properties and improved hydrophilicity, with an initial burst release of bFGF in the first few days, followed by a slow and constant release of BMP-2 up to 4 weeks. The iTE-framework shows excellent biocompatibility, significantly promoting the proliferation, migration and osteogenic differentiation of human periodontal ligament stem cells (PDLSCs) in vitro. After implantation in rat periodontal defects, the iTE-framework effectively triggers the recruitment of mesenchymal stem cells (MSCs) to the defect site, significantly promotes the formation of new bones, and facilitates the regeneration of the periodontal ligament and cementum tissue in vivo. Therefore, this sequential delivery system provides a promising therapeutic strategy for cementum-ligament-bone complex regeneration.

The growth inhibitory effect of human gingiva-derived mesenchymal stromal cells expressing interferon-ß on tongue squamous cell carcinoma cells and xenograft model.

BACKGROUND: Interferon-ß (IFN-ß) is a cytokine with pleiotropic cellular functions, including antiviral, antiproliferative, and immunomodulatory activities. IFN-ß inhibits multiple tumor cell growth in vitro. However, the contradiction between the therapeutic dose of IFN-ß and its maximally tolerated dose is still inextricable in vivo. Human gingiva-derived mesenchymal stromal cells (GMSCs) represent promising vehicles for cancer gene therapy. This study evaluated the potential of GMSCs genetically engineered to produce IFN-ß as a targeted gene delivery system to treat tongue squamous cell carcinoma (TSCC) in vitro and in vivo. METHODS: A lentiviral vector encoding IFN-ß was constructed and transfected into GMSCs to obtain IFN-ß gene-modified GMSCs (GMSCs/IFN-ß). Enzyme-linked immunosorbent assay (ELISA) was used to measure the IFN-ß concentration in conditioned medium (CM) from GMSCs/IFN-ß. The Cell Counting Kit-8 (CCK8), colony formation assay, and flow cytometry were used to detect the effects of GMSCs/IFN-ß on TSCC cell line CAL27 cell growth and apoptosis in vitro. TSCC xenograft model was developed by subcutaneous injection of CAL27 cells into BALB/c nude mouse, and the role of intravenously injected GMSCs/IFN-ß in engrafting in TSCC and controlling tumor progression was measured in vivo. RESULTS: GMSCs/IFN-ß expressed a high level of IFN-ß. Both CCK8 and colony forming assay showed that GMSCs/IFN-ß significantly inhibited the proliferation of CAL27 cells compared with the GMSCs, GMSCs/vector, or DMEM group. Flow cytometry analysis demonstrated that the CAL27 cell apoptosis rate was higher in the GMSCs/IFN-ß group than in the other three groups. The in vivo experiment revealed that GMSCs/IFN-ß engrafted selectively in TSCC xenograft and expressed a high level of IFN-ß. There were smaller tumor volume and lower number of Ki67-positive cells in the GMSCs/IFN-ß group than in the GMSCs, GMSCs/vector, or phosphate-buffered saline (PBS) group. Interestingly, GMSCs and GMSCs/vector also presented the potential of CAL27 cell growth inhibition in vitro and in vivo, although such an effect was weaker than GMSCs/IFN-ß. CONCLUSIONS: GMSCs/IFN-ß inhibits the proliferation of TSCC cells in vitro and in vivo. These results provide evidence that delivery of IFN-ß by GMSCs may be a promising approach to develop an effective treatment option for TSCC therapy.

Sequential application of bFGF and BMP-2 facilitates osteogenic differentiation of human periodontal ligament stem cells.

BACKGROUND AND OBJECTIVES: Basic fibroblast growth factor (bFGF) promotes cells proliferation and chemotaxis and maintains stemness while inhibits mineralized nodule formation. Bone morphogenetic protein 2 (BMP-2) shows great potential in promoting bone formation. However, sequential application of these two growth factors on periodontal ligament stem cells (PDLSCs) has not been explored. In this study, we aimed to identify the optimal concentration and time of bFGF on PDLSCs proliferation, migration and then investigate the sequential delivery of bFGF and BMP-2 on osteogenic differentiation of PDLSCs in vitro. MATERIALS AND METHODS: Periodontal ligament stem cells were isolated by limiting dilution method. Dose-dependent additive effects of bFGF and BMP-2 on PDLSCs were detected. Cell counting assay, cell migration assay, alkaline phosphatase (ALP) activity assay, Alizarin red staining, quantitative real-time polymerase chain reaction (qRT-PCR), and western blot analysis were used to determine different application modalities of bFGF and BMP-2 on proliferation, migration, and osteogenic differentiation of PDLSCs. RESULTS: 50 ng/mL bFGF significantly promoted PDLSCs proliferation and chemotaxis while time-dependently inhibited BMP-2 induced ALP activity. Sequential application of 25 ng/mL bFGF for first 3 days and followed with 50 ng/mL BMP-2 for another 9, 18, and 25 days significantly promoted PDLSCs osteogenic differentiation. Compared with bFGF and BMP-2 simultaneous group, sequential application of bFGF and BMP-2 group significantly enhanced ALP activity, osteogenesis-related genes and proteins expression and mineral deposition. CONCLUSION: Sequential application of bFGF and BMP-2 synergistically promoted osteogenic differentiation of PDLSCs, and this sequential application modality of growth factors would provide a new strategy for periodontal regeneration.

Rho-kinase inhibitor Y-27632 facilitates the proliferation, migration and pluripotency of human periodontal ligament stem cells.

The selective in vitro expansion and differentiation of multipotent stem cells are critical steps in cell-based regenerative therapies, while technical challenges have limited cell yield and thus affected the success of these potential treatments. The Rho GTPases and downstream Rho kinases are central regulators of cytoskeletal dynamics during cell cycle and determine the balance between stem cells self-renewal, lineage commitment and apoptosis. Trans-4-[(1R)-aminoethyl]-N-(4-pyridinyl)cylohexanecarboxamidedihydrochloride (Y-27632), Rho-associated kinase (ROCK) inhibitor, involves various cellular functions that include actin cytoskeleton organization, cell adhesion, cell motility and anti-apoptosis. Here, human periodontal ligament stem cells (PDLSCs) were isolated by limiting dilution method. Cell counting kit-8 (CCK8), 5-ethynyl-2'-deoxyuridine (EdU) labelling assay, cell apoptosis assay, cell migration assay, wound-healing assay, alkaline phosphatase (ALP) activity assay, Alizarin Red S staining, Oil Red O staining, quantitative real-time polymerase chain reaction (qRT-PCR) were used to determine the effects of Y-27632 on the proliferation, apoptosis, migration, stemness, osteogenic and adipogenic differentiation of PDLSCs. Afterwards, Western blot analysis was performed to elucidate the mechanism of cell proliferation. The results indicated that Y-27632 significantly promoted cell proliferation, chemotaxis, wound healing, fat droplets formation and pluripotency, while inhibited ALP activity and mineral deposition. Furthermore, Y-27632 induced PDLSCs proliferation through extracellular-signal-regulated kinase (ERK) signalling cascade. Therefore, control of Rho-kinase activity may enhance the efficiency of stem cell-based treatments for periodontal diseases and the strategy may have the potential to promote periodontal tissue regeneration by facilitating the chemotaxis of PDLSCs to the injured site, and then enhancing the proliferation of these cells and maintaining their pluripotency.

TiO2 nanorod arrays as a photocatalytic coating enhanced antifungal and antibacterial efficiency of Ti substrates.

AIM: To investigate the photocatalytic inactivation of fungi and bacteria mediated by TiO2 nanorod arrays (TNRs). MATERIALS & METHODS: The features of TNRs were characterized by scanning electron microscopy, atomic force microscopy, transmission electron microscopy, x-ray diffraction (XRD) and contact angle measurement. The antimicrobial efficiency was detected on biofilm and planktonic forms of Candida albicans, Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis by crystal violet and XTT (2,3-bis [2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-caboxanilide) assay, confocal laser scanning microscope and colony-forming assay. Fluorogenic quantitative assay was used to explore the underlying mechanism. RESULTS & CONCLUSION: TNRs were well aligned and vertically oriented on Ti with a diameter of about 100 µm, possessing a rougher surface and better hydrophilicity. Moreover, TNRs exhibited significantly higher antifungal and antibacterial efficiency compared with Ti under UV irradiation, laying the foundation for surface modification of implants with TNRs.

PTH/SDF-1α cotherapy promotes proliferation, migration and osteogenic differentiation of human periodontal ligament stem cells.

OBJECTIVES: Stromal cell-derived factor-1α (SDF-1α) plays an important role in tissue regeneration in various tissues including the periodontium. A potential limitation for its use derives from its sensitivity to cleavage by dipeptidyl peptidase-IV (DPP-IV). Parathyroid hormone (PTH) reduces enzymatic activity of DPP-IV and is suggested to be a promising agent for periodontal tissue repair. The purpose of this study was to provide insight into how SDF-1α and intermittent PTH treatment might affect proliferation, migration and osteogenic differentiation of human periodontal ligament stem cells (PDLSCs) in vitro. MATERIALS AND METHODS: PDLSCs were isolated by the limiting dilution method. Surface markers were quantified by flow cytometry. Cell-counting kit-8 (CCK8), cell migration assay, alkaline phosphatase (ALP) activity assay, alizarin red staining and RT-PCR were used to determine viability, migration and osteogenic differentiation of PDLSCs. RESULTS: PDLSCs were positive for CD44, CD73, CD90, CD105, CD166 and STRO-1 and negative for CD14, CD34 and CD45. PTH/SDF-1α cotherapy significantly promoted cell proliferation, chemotactic capability, ALP activity and mineral deposition (P<.05). Gene expression level of bone sialoprotein (BSP), runt-related transcription factor 2 (Runx2) and osteocalcin (OCN) were all up-regulated (P<.05). CONCLUSIONS: PTH/SDF-1α cotherapy promoted proliferation, migration and osteogenic differentiation of PDLSCs in vitro. Cotherapy seemed to have potential to promote periodontal tissue regeneration by facilitating chemotaxis of PDLSCs to the injured site, followed by promoting proliferation and osteogenic differentiation of these cells.

PTH/SDF-1α cotherapy induces CD90+CD34- stromal cells migration and promotes tissue regeneration in a rat periodontal defect model.

Stromal cell-derived factor-1α (SDF-1α) is a key stem cell homing factor that is crucial for recruitment of stem cells to many diseased organs. However, the therapeutic activity of SDF-1α is potentially limited by N-terminal cleavage at position-2 proline by a cell surface protein CD26/dipeptidyl peptidase-IV (DPP-IV). Parathyroid hormone (PTH) is a DPP-IV inhibitor and has been suggested as a promising agent for periodontal tissue repair. The purpose of this study was to explore the effects of a cell-free system comprising SDF-1α and scaffold plus PTH systemic application on periodontal tissue regeneration in vivo. The results showed that PTH/SDF-1α cotherapy improved the quantity of regenerated bone and resulted in better organization of ligament interface. We further investigated the possible mechanisms, and found that PTH/SDF-1α cotherapy enhanced CD90+CD34- stromal cells migration in vivo, increased the number of CXCR4 + cells in periodontal defects, induced early bone osteoclastogenesis and enhanced the expression of runt-related transcription factor 2 (Runx2), alkaline phosphatase (ALP) and collagen I (Col I) in newly formed bone tissue. In conclusion, this cell-free tissue engineering system with local administration of SDF-1α and systemic application of PTH could be employed to induce CD90+CD34- stromal cells recruitment and promote periodontal tissue regeneration.

Isolation and characterization of human gingiva-derived mesenchymal stem cells using limiting dilution method.

BACKGROUND/PURPOSE: Gingiva-derived mesenchymal stem cells (GMSCs) are attractive alternative MSC sources because of their relative abundance of sources and ease of accessibility. However, the isolation method for harboring GMSCs remains under discussion. The aim of the study was to isolate and explore in vitro characterization of human GMSCs, and compare stem cell properties with bulk-cultured gingival fibroblasts (GFs). MATERIALS AND METHODS: GMSCs were isolated with limiting dilution method. Tissue-matched bulk-cultured GFs and GMSCs were evaluated in terms of their colony-forming abilities, population doubling capacities, cell surface epitopes, and multilineage differentiation potentials. RESULTS: GMSCs showed a significantly higher number of colony-forming units-fibroblast (P < 0.001) than bulk-cultured GFs, while the population doubling capacity of GMSCs reduced. Both types of cells were uniformly positive for MSC-associated makers CD44, CD73, CD90, CD105, and CD166, and were negative for hematopoietic markers CD14, CD34, and CD45. The only distinct marker was STRO-1, which was more highly expressed in GMSCs (13.4%) than in bulk-cultured GFs (0.02%). Upon induction, GMSCs displayed the capacity to undergo osteogenic, adipogenic, and chondrogenic differentiation. Real-time polymerase chain reaction showed related gene levels were significantly upregulated (P < 0.001). By contrast, bulk-cultured GFs lacked the capacity to undergo multilineage differentiation, and related gene levels showed no significant difference when compared with control groups. CONCLUSION: The data validate the effectiveness of limiting dilution method for GMSCs isolation. GMSCs, in contrast to bulk-cultured GFs, harbor stem cell characteristics and can act as alternative cell sources for tissue engineering.

[Culturing and characterization of human gingival mesenchymal stem cells and their chemotactic responses to stromal cell-derived factor-1].

OBJECTIVE: To investigate the expression of chemokine stromal cell-derived factor-1 (SDF-1) receptor CXCR4 in human gingival mesenchymal stem cells (GMSCs) and the migration potential of GMSCs stimulated with SDF-1. METHODS: Human GMSCs were isolated by single-cell cloning method. Their cell surface markers were characterized by flow cytometry, and the rate of colony formation was evaluated. Differentiation assay was used to detect the differentiation potential of GMSCs. The expression of chemokine SDF-l receptor CXCR4 in GMSCs was detected by immunocytochemical staining. The chemotactic effect of SDF-1 on GMSCs was detected using a 24-multiwell Transwell cell culture chamber. The number of net migrated cells was counted in different microscope fields. RESULTS: Human GMSCs possessed high self-renewal potential and formed single-cell colonies cultured in vitro. GMSCs expressed mesenchymal stem cells-associated markers CD44, CD73, CD90, CD105, and CD166, and the expression of hemopoietic stem cell surface markers CD14, CD34, and CD45 was negative. GMSCs differentiated into osteoblasts and adipocytes under defined culture conditions. The colony forming unit-fibroblastic for GMSCs was 21.4%/±2.8%. Immunocytochemical staining demonstrated that GMSCs expressed chemokine SDF-1 receptor CXCR4. The number of GMSCs migrating at concentrations of 100 ng.mL-1 and 200 ng.mL-1 of SDF-l in the Transwell cell culture chamber was significantly higher than that of the negative control (189.3±4.4, 164.6±4.9 cells/field vs. 47.8±2.5 cells/field, P<0.01). Treatment with the CXCR4 neutralizing antibody, an antagonist for CXCR4, significantly reduced the migratory effect compared with the negative controls (29.0±2.4 cells/field vs. 47.8±2.5 cells/field, P<0.01). CONCLUSION: Human GMSCs express chemokine SDF-l receptor CXCR4. SDF-1 may participate in regulating chemotaxis of human GMSCs. Results suggest that the migration induced by SDF-1 is mediated by CXCR4.

Local administration of stromal cell-derived factor-1 promotes stem cell recruitment and bone regeneration in a rat periodontal bone defect model.

Stromal cell-derived factor-1 (SDF-1) recruits adult stem/progenitor cells via its specific receptor, C-X-C motif receptor 4 (CXCR4), to promote heart, kidney and tendon regeneration, but little is known about the effects of SDF-1 on bone regeneration in periodontal diseases. The objective of this study was to investigate whether local administration of SDF-1 in a collagen membrane scaffold enhanced the recruitment of host stem cells and improved periodontal bone defect repair. To this end, bone defects were established on the buccal side of bilateral mandibles in Wistar rats. After application of collagen membranes loaded with SDF-1 or phosphate-buffered saline (PBS) to the defects, the effects of SDF-1 on stem cell recruitment, inflammatory cell responses, angiogenesis, osteoclastogenesis, scaffold degradation, and bone regeneration were evaluated. It showed that SDF-1 recruited host-derived mesenchymal stem cells and hematopoietic stem cells to the wound area and significantly reduced the CD11b+ inflammatory cell response. Moreover, SDF-1 increased vascular formation, induced early bone osteoclastogenesis, accelerated scaffold degradation, and promoted the quality and quantity of regenerated bone. Our results suggest that this cell-free approach by local administration of SDF-1 may be an effective strategy for development as a simple and safe technique for periodontal bone regeneration.

[Culturing and characterization of human periodontal ligament stem cells and investigating their chemotactic responses to bone morphogenetic protein-2].

OBJECTIVE: To investigate the chemotactic response of human periodontal ligament stem cells (PDLSCs) to bone morphogenetic protein-2 (BMP-2). METHODS: Human PDLSCs were obtained from clinically healthy premolars extracted for orthodontic reasons and used to isolate PDLSCs by limited dilution method. The expression of Vimentin and stem cell marker STRO-1 on PDLSCs were demonstrated with immunocytochemical staining. Differentiation assay was used to detect the differentiation potential of PDLSCs. Cloning formation experiment and 5-bromo-2-deoxyuridine (BrdU) incorporation assay were used to determine the stem cell characteristics of PDLSCs. The chemotactic effect of BMP-2 on PDLSCs was detected by using a 24-multiwell Transwell cell culture chamber. The number of net migrated cells was counted in different microscope fields. RESULTS: Human PDLSCs displayed positive staining for Vimentin and expressed the stem cell marker STRO-1. These cells differentiated into osteoblasts and adipocytes under defined culture conditions, possessed high self-renewal potential and formed single-cell colonies in vitro. The number of cells migrating at concentrations of 100, 200 ng mL(-1) of BMP-2 in Transwell cell culture chamber was significantly higher than that of negative control (P<0.01). CONCLUSION: BMP-2 may participate in regulating chemotaxis of human PDLSCs.

Stromal cell-derived factor-1 significantly induces proliferation, migration, and collagen type I expression in a human periodontal ligament stem cell subpopulation.

BACKGROUND: The pivotal role of chemokine stromal cell-derived factor-1 (SDF-1) in bone marrow mesenchymal stem cells recruitment and tissue regeneration has already been reported. However, its roles in human periodontal ligament stem cells (PDLSCs) remain unknown. PDLSCs are regarded as candidates for periodontal tissue regeneration and are used in stem cell-based periodontal tissue engineering. The expression of chemokine receptors on PDLSCs and the migration of these cells induced by chemokines and their subsequent function in tissue repair may be a crucial procedure for periodontal tissue regeneration. METHODS: PDL tissues were obtained from clinically healthy premolars extracted for orthodontic reasons and used to isolate single-cell colonies by the limited-dilution method. Immunocytochemical staining was used to detect the expression of the mesenchymal stem cell marker STRO-1. Differentiation potentials were assessed by alizarin-red staining and oil-red O staining. The expression of SDF-1 receptor CXCR4 was evaluated by real-time polymerase chain reaction (PCR) and immunocytochemical staining. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and bromodeoxyuridine incorporation assay were used to determine the viability and proliferation of the PDLSC subpopulation. Expression of collagen type I and alkaline phosphatase was detected by real-time PCR to determine the effect of SDF-1 on cells differentiation. RESULTS: Twenty percent of PDL single-cell colonies expressed STRO-1 positively, and this specific subpopulation was positive for CXCR4 and formed minerals and lipid vacuoles after 4 weeks induction. SDF-1 significantly increased proliferation and stimulated the migration of this PDLSC subpopulation at concentrations between 100 and 400 ng/mL. CXCR4 neutralizing antibody could block cell proliferation and migration, suggesting that SDF-1 exerted its effects on cells through CXCR4. SDF-1 promoted collagen type I level significantly but had little effect on alkaline phosphatase level. CONCLUSION: SDF-1 may have the potential of promoting periodontal tissue regeneration by the mechanism of guiding PDLSCs to destructive periodontal tissue, promoting their activation and proliferation and influencing the differentiation of these stem cells.