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ABSTRACT: Stem cell differentiation is modulated by several key molecules, including cytokines, hormones, and engineered peptides. Emerging evidence suggests that microRNA has potential applications in stem cell engineering, such as in osteoblastic differentiation. MicroRNAs (miRNAs) bind to the 3'-untranslated region (UTR) sequence of target mRNA, thereby attenuating protein synthesis. Our goal was to evaluate the delivery of miRNA, i.e., miRNA-29b, to stem cells to promote osteoblastic differentiation because this miRNA is known to target anti-osteogenic factors gene expression. Despite the important role of miRNAs, their application has been limited due to poor cell/tissue penetration. The authors attempted to overcome this limitation by using a cell-penetrating peptide (CPP) carrier. Herein, the arginine-rich CPP, called the lowmolecular weight protamine (LMWP), is the sequence from natural protamine. We worked out the difficult problem to transfect into hMSCs by the complex with LMWP, and then we investigated synthetic double-stranded miR-29b could be induced osteoblast differentiation.
Biomaterials 03/2013; · 7.40 Impact Factor
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ABSTRACT: Dentin sialophosphoprotein (DSPP) has been shown to play a primary role in the formation and growth of hydroxyapatite crystals in an extracellular matrix of hard tissue such as bone and teeth. We hypothesized that the mineralization ability of DSPP might depend on a specific domain within it. Three peptides, which have hydroxyapatite (HA) binding affinity, denoted as mineralization inducing peptide (MIP1, MIP2, and MIP3) were identified from DSPP. The both of MIP2 and MIP3 had HA nucleation activity demonstrated by XRD. Among three MIPs, MIP3 significantly supported the human bone marrow stromal cell differentiation into osteoblastic cells. An immunoblot with antibodies specific for the phosphorylated forms of ERK was conducted with cells treated by MIP3. MIP3 transduced intracellular signals via the ERK pathways and was able to induce osteoblastic differentiation, as seen by high expression of ALP, type 1 collagen, OC, OPN, and Runx2 in accordance with applied MIP3 concentration. The Asp, Glu, and Ser residues in MIP3 play important roles for the affinity of calcium in HA bone mineral. Further animal experiment with MIP3 in combination with hydroxyapatite mineral induced marked new bone formation for 4 weeks at rabbit calvarial defect model. The new bone area was much higher in test group, implying that the peptide modified group had excellent biocompatibility when compared with the unmodified group. Taken together, the MIP from DSPP has potential to enhance mineralization followed by to enhance osteoblastic differentiation and bone regeneration. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.
Journal of Biomedical Materials Research Part A 09/2012; · 2.63 Impact Factor
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ABSTRACT: Bone sialoprotein (BSP) is a mineralized, tissue-specific, and noncollagenous protein. The binding of BSP to collagen is thought to be important for the initiation of bone mineralization and formation. In this study, we elucidated the osteogenic efficiency of the collagen-binding (CB) peptide derived from BSP in vitro and in vivo. The CB peptide increased osteoblastic differentiation marker gene and protein expression without affecting cell proliferation. The osteoblastic differentiation by the CB peptide is performed by the activation of extracellular signal-regulated kinase (ERK1/2) and protein kinase B (Akt). Notably, the activation of CB peptide-induced osteogenic differentiation was completely blocked to the basal level by the specific inhibitors for ERK1/2 (U0126) and Akt (LY294002). In vivo results further demonstrated that the CB peptide-coated hydroxyapatite scaffold was able to induce bone formation in the bone defect. Taken together, the CB peptide can be developed as an osteoblastic differentiation agent as well as a fusion biomaterial for bone regeneration therapy. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2012.
Journal of Biomedical Materials Research Part A 08/2012; · 2.63 Impact Factor
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ABSTRACT: Bone sialoprotein (BSP) is a mineralized, tissue-specific, non-collagenous protein that is normally expressed only in mineralized tissues such as bone, dentin, cementum, and calcified cartilage, and at sites of new mineral formation. The binding of BSP to collagen is thought to be important for initiating bone mineralization and bone cell adhesion to the mineralized matrix. Several recent studies have isolated stem cells from muscle tissue, but their functional properties are still unclear. In this study, we examined the effects of a synthetic collagen-binding peptide (CBP) on the differentiation efficiency of muscle-derived stem cells (MDSCs). The CBP sequence (NGVFKYRPRYYLYKHAYFYPHLKRFPVQ) corresponds to residues 35-62 of bone sialoprotein (BSP), which are located within the collagen-binding domain in BSP. Interestingly, this synthetic CBP inhibited adipogenic differentiation but increased osteogenic differentiation in MDSCs. The CBP also induced expression of osteoblastic marker proteins, including alkaline phosphatase (ALP), type I collagen, Runt-related transcription factor 2 (Runx2), and osteocalcin; prevented adipogenic differentiation in MDSCs; and down-regulated adipose-specific mRNAs, such as adipocyte protein 2 (aP2) and peroxisome proliferator-activated receptor γ. The CBP increased Extracellular signal-regulated kinases (ERK) 1/2 protein phosphorylation, which is important in lineage determination. These observations suggest that this CBP determines the osteogenic or adipogenic lineage in MDSCs by activating ERK1/2. Taken together, a novel CBP could be a useful candidate for regenerating bone and treating osteoporosis, which result from an imbalance in osteogenesis and adipogenesis differentiation.
Biochemical and Biophysical Research Communications 02/2012; 419(2):326-32. · 2.48 Impact Factor
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ABSTRACT: A heparin-binding peptide (HBP) sequence from human heparin-binding epidermal growth factor-like growth factor (HB-EGF) was identified and was shown to exhibit cell penetration activity. This cell penetration induced an anti-inflammatory reaction in lipopolysaccharide (LPS)-treated RAW 264.7 macrophages. HBP penetrated the cell membrane during the 10 min treatment and reduced the LPS-induced production of nitric oxide (NO), inducible nitric oxide synthase (iNOS), and cytokines (TNF-α and IL-6) in a concentration-dependent manner. Additionally, HBP inhibited the LPS-induced upregulation of cytokines, including TNF-α and IL-6, and decreased the interstitial infiltration of polymorphonuclear leukocytes in a lung inflammation model. HBP inhibited NF-κB-dependent inflammatory responses by directly blocking the phosphorylation and degradation of IκBα and by subsequently inhibiting the nuclear translocation of the p65 subunit of NF-κB. Taken together, this novel HBP may be potentially useful candidate for anti-inflammatory treatments and can be combined with other drugs of interest to transport attached molecules into cells.
Biochemical and Biophysical Research Communications 02/2012; 419(4):597-604. · 2.48 Impact Factor
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ABSTRACT: Human dental pulp stem cells (DPSCs) have potential applications in tissue regeneration because of their convenient cell harvesting procedures and multipotent capacity. However, the tissue regenerative potential of DPSCs is known to be negatively regulated by aging in long-term culture and under oxidative stress. With an aim of reducing cellular senescence and oxidative stress in DPSCs, an intracellular delivery system for superoxide dismutase 1 (SOD1) was developed. We conjugated SOD1 with a cell-penetrating peptide known as low-molecular weight protamine (LMWP), and investigated the effect of LMWP-SOD1 conjugates on hydrogen peroxide-induced cellular senescence and osteoblastic differentiation.
LMWP-SOD1 significantly attenuated enlarged and flattened cell morphology and increased senescence-associated β-galactosidase activity. Under the same conditions, LMWP-SOD1 abolished activation of the cell cycle regulator proteins, p53 and p21(Cip1), induced by hydrogen peroxide. In addition, LMWP-SOD1 reversed the inhibition of osteoblastic differentiation and downregulation of osteogenic gene markers induced by hydrogen peroxide. However, LMWP-SOD1 could not reverse the decrease in odontogenesis caused by hydrogen peroxide.
Overall, cell-penetrating LMWP-SOD1 conjugates are effective for attenuation of cellular senescence and reversal of osteoblastic differentiation of DPSCs caused by oxidative stress inhibition. This result suggests potential application in the field of antiaging and tissue engineering to overcome the limitations of senescent stem cells.
International Journal of Nanomedicine 01/2012; 7:5091-106. · 3.13 Impact Factor
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ABSTRACT: Recent researches have indicated a role for antihypertensive drugs including alpha- or beta-blockers in the prevention of bone loss. Some epidemiological studies reported the protective effects of those agents on fracture risk. However, there is limited information on the association with those agents especially at the mechanism of action. In the present study, we investigated the effects of doxazosin, an alpha-blocker that is clinically used for the treatment of benign prostatic hyperplasia (BPH) along with antihypertensive medication, on the osteogenic stem cell differentiation. We found that doxazosin increased osteogenic differentiation of human mesenchymal stem cells, detected by Alizarin red S staining and calcein. Doxazosin not only induced expression of alkaline phosphatase, type I collagen, osteopontin, and osteocalcin, it also resulted in increased phosphorylation of extracellular signal-regulated kinase (ERK1/2), a MAP kinase involved in osteoblastic differentiation. Treatment with U0126, a MAP kinase inhibitor, significantly blocked doxazosin-induced osteoblastic differentiation. Unrelated to activation of osteogenic differentiation by doxazosin, we found that there were no significant changes in adipogenic differentiation or in the expression of adipose-specific genes, including peroxisome proliferator-activated receptor γ, aP2, or LPL. In this report, we suggest that doxazosin has the ability to increase osteogenic cell differentiation via ERK1/2 activation in osteogenic differentiation of adult stem cells, which supports the protective effects of antihypertensive drug on fracture risk and according to our data doxazosin might be useful for application in the field of bone metabolism.
Biochemical and Biophysical Research Communications 12/2011; 416(3-4):232-8. · 2.48 Impact Factor
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ABSTRACT: Bioactive biomaterials are desirable as tissue engineering scaffolds by virtue of their capability to mimic the natural environment of the extracellular matrix. Bioactive biomaterials have been achieved by incorporating synthetic short peptide sequences into suitable materials either by surface modification or by bulk incorporation. The goal is to enhance cell attachment and other basic functions. Bioactive peptides can be obtained from biological or chemically synthesized sources, increasing their specific cellular responses for tissue growth and development. Compared to using an entire growth factor in regenerative therapy, these peptides demonstrate potential advantages such as overcoming possible immunogenicity, being less susceptible to degradation, and producing fewer tumor-related side effects. Biomaterial scaffolds modified with peptides can provide biological ligands for cell-scaffold interactions that promote cell attachment, proliferation, and differentiation. Peptide-based biomaterial scaffolds can be fabricated to form two- and three-dimensional structures. This review discusses cell-binding, biominerailization inducing peptides, and receptor-binding peptides for bone regeneration. This review also addresses issues related to peptide immobilization as well as potential complications that may develop as a result of using these versatile bioactive peptides. The development of self-assembled peptide amphiphiles with the goal of generating new three-dimensional scaffolds for tissue engineering is also summarized.
Current pharmaceutical design 07/2011; 17(25):2663-76. · 4.41 Impact Factor
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ABSTRACT: In this study, a cell-penetrating peptide, the transactivating transcriptional factor (TAT) domain from HIV, was linked to a chitosan/doxorubicin (chitosan/DOX) conjugate to form a chitosan/DOX/TAT hybrid. The synthesized chitosan/DOX/TAT conjugate showed a different intracellular distribution pattern from a conjugate without TAT. Unlike both free DOX and the conjugate without TAT, the chitosan/DOX/TAT conjugate was capable of efficient cell entry. The chitosan/DOX/TAT conjugate was found to be highly cytotoxic, with an IC(50) value of approximately 480 nM, 2 times less than that of chitosan/DOX (980 nM). The chitosan/DOX/TAT provided decreases in tumor volume of 77.4 and 57.5% compared to free DOX and chitosan/DOX, respectively, in tumor-bearing mice. Therefore, this study suggests that TAT-mediated chitosan/DOX conjugate delivery is effective in slowing tumor growth.
International Journal of Cancer 05/2011; 128(10):2470-80. · 5.44 Impact Factor
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ABSTRACT: In previous studies, oligopeptide corresponding to the cell-binding domains of bone morphogenetic proteins that bind to bone morphogenetic protein receptor enhanced the bone regenerative capacity of bovine bone minerals (BBM). The aim of this study is to evaluate the ability of BBM coated with oligopeptide to promote periodontal regeneration in a 1-wall intrabony defect model in dogs.
The second and third mandibular premolars and first molars of six adult beagles were extracted bilaterally, and the extraction sites were allowed to heal for 10 weeks. The 1-wall intrabony defects were prepared bilaterally on the mesial and distal side of the fourth mandibular premolars. Twenty-four intrabony defects were assigned to four treatment groups: 1) open flap debridement; 2) guided tissue regeneration (GTR); 3) GTR with a collagen membrane and BBM; and 4) GTR with a collagen membrane and BBM coated with the oligopeptide (Pep-BBM). The animals were sacrificed 10 weeks after surgery. For the histometric analysis, defect height, junctional epithelium migration, new cementum, new bone height, and new bone area were measured. New bone volume was measured using microcomputed tomography.
Wound healing was generally uneventful. For junctional epithelium migration, the BBM and Pep-BBM groups exhibited mean (± SE) values of 0.53 ± 0.41 and 0.48 ± 0.30 mm, and for new cementum height, 1.71 ± 0.46 and 2.50 ± 2.00 mm, respectively. For junctional epithelium migration and cementum regeneration, there were no significant differences between the two groups. The mean (± SE) values of new bone height and new bone volume in the Pep-BBM group (3.88 ± 0.31 mm and 32.35% ± 9.60%) were significantly greater than the mean values for the BBM group (2.60 ± 0.41 mm and 20.56% ± 1.89%). For bone regeneration, the Pep-BBM group showed superior results compared to the BBM group with statistically significant differences.
Through various parameters to evaluate periodontal regeneration, this oligopeptide coating influenced only the ability of BBM to promote bone regeneration in 1-wall intrabony defects in beagles. Junctional epithelium migration and cementum regeneration were not affected by this oligopeptide coating, and further investigations with special focus on regeneration of the periodontal ligament are necessary.
Journal of Periodontology 05/2011; 83(1):101-10. · 2.60 Impact Factor
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ABSTRACT: Anticancer drug delivery has been hindered due to cell membrane permeability and the lack of a selective marker for tumor cells. Cell permeability is related to the bioavailability of drugs and has therefore been considered to be an essential step for achieving therapeutic efficacy. While different types of transporters currently exist, cell penetrating peptides (CPPs) have become one of the most popular and effective tools for intracellular drug delivery. Most of the original CPPs are short peptides with basic residues. The mechanism of CPP cell entry remains to be established; however, the CPPs can deliver any type of molecular cargo including solid nanoparticles. Herein, this paper will discuss the classification of CPPs, the mechanism of cell entry, the application of CPPs in tumor therapy, and recent advances in targeted cell penetration that involve CPPs.
Current pharmaceutical biotechnology 04/2011; 12(8):1166-82. · 3.40 Impact Factor
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ABSTRACT: Connective tissue reattachment to periodontally damaged root surfaces is one of the most important goals of periodontal therapy. The aim of this study was to develop a root conditioning agent that can demineralize and detoxify the infected root surface.
Dentin slices obtained from human teeth were treated with a novel root planing agent for 2 minutes and then washed with phosphate-buffered saline. Smear layer removal and type I collagen exposure were observed by scanning electron microscopy (SEM) and type I collagen immunostaining, respectively. Cell attachment and lipopolysaccharides (LPS) removal demonstrated the efficiency of the root conditioning agent.
SEM revealed that the smear layer was entirely removed and the dentinal tubules were opened by the experimental gel. Type I collagen was exposed on the surfaces of the dentin slices treated by the experimental gel, which were compared with dentin treated with other root planing agents. Dentin slices treated with the experimental gel showed the highest number of attached fibroblasts and flattened cell morphology. The agar diffusion assay demonstrated that the experimental gel also has effective antimicrobial activity. Escherichia coli LPS were effectively removed from well plates by the experimental gel.
These results demonstrated that this experimental gel is a useful tool for root conditioning of infected root surfaces and can also be applied for detoxification of ailing implant surface threads.
Journal of periodontal & implant science 12/2010; 40(6):257-64.
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ABSTRACT: To prolong the degradation time of collagen membranes, various cross-linking techniques have been developed. For cross-linking, chemicals such as formaldehyde and glutaraldehyde are added to collagen membranes, but these chemicals could adversely affect surrounding tissues. The aim of this study is to evaluate the ability of porous non-chemical cross-linking porcine-derived collagen nanofibrous membrane to enhance bone and associated tissue regeneration in one-wall intrabony defects in beagle dogs.
The second and third mandibular premolars and the first molars of 2 adult beagles were extracted bilaterally and the extraction sites were allowed to heal for 10 weeks. One-wall intrabony defects were prepared bilaterally on the mesial and distal side of the fourth mandibular premolars. Among eight defects, four defects were not covered with membrane as controls and the other four defects were covered with membrane as the experimental group. The animals were sacrificed 10 weeks after surgery.
Wound healing was generally uneventful. For all parameters evaluating bone regeneration, the experimental group showed significantly superior results compared to the control. In new bone height (NBh), the experimental group exhibited a greater mean value than the control (3.04 ± 0.23 mm/1.57 ± 0.59, P = 0.003). Also, in new bone area (NBa) and new bone volume (NBv), the experimental group showed superior results compared to the control (NBa, 34.48 ± 10.21% vs. 5.09 ± 5.76%, P = 0.014; and NBv, 28.04 ± 12.96 vs. 1.55 ± 0.57, P = 0.041). On the other hand, for parameters evaluating periodontal tissue regeneration, including junctional epithelium migration and new cementum height, there were no statistically significant differences between two groups.
Within the limitations of this study, this collagen membrane enhanced bone regeneration at one-wall intrabony defects. On the other hand, no influence of this membrane on periodontal tissue regeneration could be ascertained in this study.
Journal of periodontal & implant science 10/2010; 40(5):232-8.
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Hyun-Wook Nam,
Jun-Beom Park, Jue Yeon Lee,
Sang-Hoon Rhee,
Sang-Chul Lee,
Ki-Tae Koo,
Tae-Il Kim,
Yang-Jo Seol,
Yong-Moo Lee,
Young Ku,
In-Chul Rhyu,
Yoon-Jeong Park,
Chong Pyoung Chung
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ABSTRACT: The ridge-preservation technique has been applied with membrane alone or membrane plus graft. Synthetic peptides, mimicking bioactive growth factor or extracellular matrix protein, have been attempted to provide an active surface of the biomaterials in inducing bone formation while alleviating the limitations of whole protein such as short half-life, immunologic responses. The aim of the present clinical study is to examine the osteogenic effect of synthetic oligopeptide-coated bone mineral compared to bone graft without peptide when applied with collagen membrane in a ridge-preservation technique.
Synthetic oligopeptide from the collagen-binding domain of osteopontin was chemically synthesized and coated onto the surface of bone mineral particulates. Ridge preservations were performed at 44 extraction sites in 42 patients (20 males and 22 females). Analyses of clinical parameters and histomorphometric evaluations were conducted to compare the osteogenic effects of the grafts between baseline and 6 months.
In the bone grafts of the control group treated without synthetic peptide, new bone formation was only seen around borders and basal areas. However, new bone was observed broadly in the defects of the test group treated with synthetic peptide-coated bone mineral, as seen not only at peripheries but also in the central and coronal parts of bone cores in the defects. The average percentage of new bone formation was significantly higher in the test group (5.3% ± 8.3% versus 10.4% ± 4.6%). The contact percentages between the graft particles and the new bone were 8.2% ± 11.3% for the control group and 20.4% ± 7.5% for the test group (P <0.05).
The ridge-preservation approach using synthetic oligopeptide-coated bone mineral with collagen membrane effectively prevented the resorption of hard tissue with higher bone-to-graft contact, and the oligopeptide-coated bone may be a choice for ridge-preservation procedures while assuring new bone formation.
Journal of Periodontology 10/2010; 82(3):471-80. · 2.60 Impact Factor
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ABSTRACT: The presence of heparin binding has been become crucial in exerting growth factor related tissue formation. Receptor-mediated osteoblastic differentiation by bone morphogenetic protein (BMP)-4 and supportive function of its heparin binding has been proposed, direct role of the heparin binding site of BMP-4 on osteogenesis has not yet been fully investigated. If the binding site itself plays role on osteogenesis, the site domain can be useful in bone formation in combination with biomaterial. Herein, we synthesized a peptide sequence corresponding to residues 15-24 of BMP-4 (HBD, RKKNPNCRRH), as potential heparin binding sequence. The HBD peptide-induced ostoegenic differentiation by activating extracellular signal-regulated kinase (ERK1/2), one of the key regulators in hMSC. Also, treatment of cultured hMSCs with heparinase blocked both HBD peptide-induced osteogenic differentiation and GAG chain detection while abolishing the increased phospho-ERK level. These results suggest that the identified heparin binding domain peptide (HBD) stimulated osteoblastic differentiation via interaction with heparin and the ERK signaling. In vivo results further demonstrated that HBD, as a form of complex with alginate gel, was able to induce bone formation in the bone defect.
Biomaterials 10/2010; 31(28):7226-38. · 7.40 Impact Factor
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ABSTRACT: Small interfering RNAs (siRNAs), used for specific down-regulation of targeted genes, have garnered considerable interest as an attractive new class of drugs for broad clinical applications. The polyanionic charges carried by these siRNAs, however, restrain cellular uptake and consequently limit effects on gene regulation. Herein the authors describe a peptide/siRNA complex containing the cell penetrating peptide derived from natural protamine, termed low molecular weight protamine (LMWP), for the treatment of cancer. Fluorescently-tagged siRNAs were localized with the peptide in the cytoplasm shortly after incubation of LMWP/siRNA complex with carcinoma cells. The increased cell uptake of siRNA that was achieved using the LMWP resulted in significant down-regulation of model protein luciferase as well as therapeutic cancer target, vascular endothelial growth factor (VEGF) expression. In vivo studies with tumor-bearing mice further demonstrated that the peptide could carry and localize siRNA inside tumors and inhibit the expression of VEGF through systemic application of the peptide complex, thereby suppressing tumor growth. In addition, no detectable increase in the serum level of inflammatory cytokines including interferon (IFN)-alpha and interleukin (IL)-12 was observed under the LMWP/siRNA complex treatment, indicating systemic delivery of LMWP/siRNA did not exert measurable immunostimulatory effect. The LMWP-based systemic delivery method could be a reliable and safe approach to maximize effectiveness of therapeutic siRNA for treatment of cancer and other diseases.
Biomaterials 11/2009; 31(6):1429-43. · 7.40 Impact Factor
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ABSTRACT: Self-assembled nanostructures consisting of BMP receptor-binding peptides, termed osteopromotive domains (OPDs), and hydrophobic alkyl chains were fabricated with the aim of developing three-dimensional scaffolding materials for osteoblastic differentiation. OPD peptide was identified from BMP-2 and had an affinity for BMP receptors thereby inducing differentiation of human bone marrow stromal cells into osteoblastic cells. The peptide-hydrophobic alkyl chain amphiphiles were designed to mimic nanofibrous extracellular structures and to add osteogenic ligands to enhance osteoblastic cell function. The OPD peptide-amphiphiles (OPDAs) that end with the alkylation of the N-terminus of the OPD peptide were synthesized by standard solid phase chemistry. The self-assembly was triggered by mixing OPDA solution with calcium ions. Observation using scanning electron microscopy (SEM) revealed the formation of nanofibrous structures with extremely high aspect ratios and high surface areas. The FT-IR and circular dichroism (CD) spectrophotometry demonstrated that self-assembled nanofibers have a beta-sheet structure. The activation of Smad, an osteoblastic differentiation marker, was obtained in the cell culture gel of self-assembled OPDA; therefore, the intracellular signal transduction for osteogenesis was performed like an OPD peptide. Cell survival was supported in the OPDA gel for 10 days, and osteoblastic differentiation of human bone marrow stromal cells (hBMSCs) was evident as demonstrated by calcein staining and ALP activity measurement. These results revealed that self-assembled OPDA maintained osteogenic activity by the surface-exposed OPD peptide. Taken together, the self-assembled OPDA nanofibrous gel can be utilized as a cell culture scaffold in bone regeneration.
Biomaterials 05/2009; 30(21):3532-41. · 7.40 Impact Factor
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ABSTRACT: Two cell-binding domains from FGF-2 (fibroblast growth factor-2) were shown to increase cell attachment and osteoblastic differentiation. Two synthetic peptides derived from FGF-2, namely residues 36-41 (F36; PDGRVD) and 77-83 (F77; KEDGRLL), were prepared and their N-termini further modified for ease of surface immobilization. Chitosan membranes were used in the present study as mechanical supportive biomaterials for peptide immobilization. Peptides could be stably immobilized on to the surface of chitosan membranes. The adhesion of mesenchymal stem cells to the peptide (F36 and F77)-immobilized chitosan membrane was increased in a dose-dependent manner and completely inhibited by soluble RGD (Arg-Gly-Asp) and anti-integrin antibody, indicating the existence of an interaction between F36/F77 and integrin. Peptide-immobilized chitosan supported human bone-marrow-derived mesenchymal-stem-cell differentiation into osteoblastic cells, as demonstrated by alkaline phosphate expression and mineralization. Taken together, the identified peptide-immobilized chitosan membranes were able to support cell adhesion and osteoblastic differentiation; thus these peptides might be useful as bioactive agents for osteoblastic differentiation and surface-modification tools in bone regenerative therapy.
Biotechnology and Applied Biochemistry 03/2008; 52(Pt 1):69-77. · 1.53 Impact Factor
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ABSTRACT: A 15-mer synthetic peptide, designated P1, was derived from the bone morphogenetic protein (BMP) receptor I and BMP receptor II binding domains of BMP-2 for the purpose of enhancing bone regeneration capacity of inorganic bovine bone mineral. A second peptide, denoted P2, was designed by adding seven glutamic acid residues to the N-terminal of P1 to increase the surface coating efficiency onto bone mineral. The coating efficiency of P1 increased with the concentration of peptide. P2 peptide, in contrast, had a higher coating efficiency at lower peptide concentrations. The peptides properly transduced intracellular signals properly via the Smad and ERK pathways, thereby increasing mineralization in vitro, implying that the peptides alone can induce osteoblastic differentiation. Adhesion of cells to bone mineral was greater when peptides were present than in bone mineral alone. P1- and P2-coated bone mineral increased osteoblastic differentiation, as demonstrated by ALPase activity. P1-coated bone mineral stimulated more new bone regeneration in bone defect sites after 2 weeks than the peptide-free control. These peptides, in combination with bone grafts or implants, have the potential to enhance osteoblastic differentiation and bone regeneration.
Journal of Biomedical Materials Research Part A 02/2008; 87(3):688-97. · 2.63 Impact Factor
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ABSTRACT: Novel chitosan-poly(lactide-co-glycolide) (PLGA) composite fibers and nonwoven fibrous scaffolding matrices were designed for cartilage regeneration. A homogenous one-phase mixture of chitosan and PLGA at a ratio of 50:50 (w/w %) was successfully produced using cosolvents of 1,1,1,3,3,3-hexafluoroisopropanol and methylene chloride. A wet spinning technique was employed to fabricate composite fibrous matrices. Physical characterizations of one-phase chitosan-PLGA composite (C/Pc) matrices were performed for their homogeneity, in vitro degradability, mechanical property and wettability in comparison to two-phase chitosan and PLGA composite fibrous matrices in which PLGA was dispersed in a continuous chitosan phase. The one-phase property of C/Pc matrices was confirmed from thermal analysis. Significantly retarded degradation was observed from the composite C/Pc fibrous matrices in contrast to the PLGA-dispersed chitosan (C/Pd) fibrous matrices due to the effective acid-neutralizing effect of chitosan on acid metabolites of PLGA. The composition of chitosan with PLGA resulted in a characteristic soft and strong mechanical property that could not be retained by either PLGA or the chitosan fibers. In addition, the presence of chitosan in the composite matrices provided proper wettability for cell cultivation. The C/Pc matrices were further investigated for their scaffolding function using chondrocytes for cartilage regeneration. Enhanced cell attachment was observed on the composite matrix compared with the PLGA fibrous matrices. The mRNA expression of type II collagen and aggrecan was upregulated in the composite matrix owing to the superior cell compatibility of chitosan. These results suggest an excellent potential for C/Pc one-phase composite fibrous matrices as scaffolding materials for tissue regeneration.
Journal of Biomedical Materials Research Part A 02/2008; 84(1):247-55. · 2.63 Impact Factor
