Dr. Sien Lin is currently a postdoctoral scholar at Stanford Medicine. He finished his medical training in China and got his PhD in Orthopaedics and Traumatology from the Chinese University of Hong Kong in 2015. Dr. Lin started his postdoctoral training at Stem Cells and Regenerative Medicine Lab of the Chinese University of Hong Kong from 2016. His research interests include adult stem cells and regenerative medicine in musculoskeletal system, new drug research and development for musculoskeletal diseases. He is an author of 50 peer-reviewed papers and 1 book chapter since 2012.
Honors & Awards
Student and Young Investigator Award Second Prize, Tissue Engineering and Regenerative Medicine International Society-Asia Pacific Conference 2017 (23 Sep 2017)
Best Poster of Guest Nation, 2017 Annual Conference of Orthopaedic Research Society (22 Mar 2017)
Best Poster Award, 9th International Conference on Osteoporosis and Bone Research (17-20 Oct 2018)
Best Paper Award, 4th CUHK International Stem Cell and Regenerative Medicine Conference (13 Nov 2014)
Oral Presentation Award, 4th Asia-Pacific Bone & Mineral and Research Meeting (11-13 May 2018)
Boards, Advisory Committees, Professional Organizations
Member, International Chinese Musculoskeletal Research Society (ICMRS) (2017 - Present)
Member, Orthopaedic Research Society (2017 - Present)
Administration of allogeneic mesenchymal stem cells in lengthening phase accelerates early bone consolidation in rat distraction osteogenesis model.
Stem cell research & therapy
2020; 11 (1): 129
Distraction osteogenesis (DO) is a surgical technique to promote bone regeneration which may require long duration for bone consolidation. Bone marrow-derived mesenchymal stem cells (MSCs) have been applied to accelerate bone formation in DO. However, the optimal time point for cell therapy in DO remains unknown. This study sought to determine the optimal time point of cell administration to achieve early bone consolidation in DO. We hypothesized that the ratio of circulating MSCs to peripheral mononuclear cells and the level of cytokines in serum might be indicators for cell administration in DO.Unilateral tibial osteotomy with an external fixator was performed in adult Sprague Dawley rats. Three days after osteotomy, the tibia was lengthened at 0.5 mm/12 h for 5 days. At first, 5 rats were used to analyze the blood components at 6 different time points (3 days before lengthening, on the day lengthening began, or 3, 6, 10, or 14 days after lengthening began) by sorting circulating MSCs and measuring serum levels of stromal cell-derived factor 1 (SDF-1) and interleukin 1β. Then, 40 rats were used for cell therapy study. A single dose of 5 × 105 allogeneic MSCs was locally injected at the lengthening site on day 3, 6, or 10 after lengthening began, or 3 doses of MSCs were injected at the three time points. Sequential X-ray radiographs were taken weekly. Endpoint examinations included micro-computed tomography analysis, mechanical testing, histomorphometry, and histology.The number of circulating MSCs and serum level of SDF-1 were significantly increased during lengthening, and then decreased afterwards. Single injection of MSCs during lengthening phase (on day 3, but not day 6 or 10) significantly increased bone volume fraction, mechanical maximum loading, and bone mineralization of the regenerate. Triple injections of MSCs at three time points also significantly increased bone volume and maximum loading of the regenerates.This study demonstrated that bone consolidation could be accelerated by a single injection of MSCs during lengthening when the ratio of peripheral MSCs to mononuclear cells and the serum SDF-1 presented at peak levels concurrently, suggesting that day 3 after lengthening began may be the optimal time point for cell therapy to promote early bone consolidation.
View details for DOI 10.1186/s13287-020-01635-5
View details for PubMedID 32197646
Conformational manipulation of scale-up prepared single-chain polymeric nanogels for multiscale regulation of cells
2019; 10: 2705
Folded single chain polymeric nano-objects are the molecular level soft material with ultra-small size. Here, we report an easy and scalable method for preparing single-chain nanogels (SCNGs) with improved efficiency. We further investigate the impact of the dynamic molecular conformational change of SCNGs on cellular interactions from molecular to bulk scale. First, the supramolecular unfoldable SCNGs efficiently deliver siRNAs into stem cells as a molecular drug carrier in a conformation-dependent manner. Furthermore, the conformation changes of SCNGs enable dynamic and precise manipulation of ligand tether structure on 2D biomaterial interfaces to regulate the ligand-receptor ligation and mechanosensing of cells. Lastly, the dynamic SCNGs as the building blocks provide effective energy dissipation to bulk biomaterials such as hydrogels, thereby protecting the encapsulated stem cells from deleterious mechanical shocks in 3D matrix. Such a bottom-up molecular tailoring strategy will inspire further applications of single-chain nano-objects in the biomedical area.
View details for DOI 10.1038/s41467-019-10640-z
View details for Web of Science ID 000472140100002
View details for PubMedID 31221969
View details for PubMedCentralID PMC6586678
- Anisotropic Nanoscale Presentation of Cell Adhesion Ligand Enhances the Recruitment of Diverse Integrins in Adhesion Structures and Mechanosensing-Dependent Differentiation of Stem Cells ADVANCED FUNCTIONAL MATERIALS 2019; 29 (8)
Sox11-modified mesenchymal stem cells accelerate cartilage defect repair in SD rats.
Cell and tissue research
Cartilage has a limited capacity to heal. Previously, we have shown that overexpression of Sox11 in rMSCs (Rat Mesenchymal Stem Cells) by lentivirus-mediated gene transfer leads to enhanced tri-lineage differentiation and accelerated bone formation in fracture model of rats. We observed that the fracture repair in the rats that received Sox11-modified rMSCs injection proceeded through an endochondral ossification process much faster than those in the control groups. However, the detailed role of Sox11 in rMSCs chondrogenic differentiation, as well as cartilage defect, is still not clearly clarified. Therefore, this study tests the hypothesis that Sox11 promotes chondrogenesis and cartilage defect repair by regulating β-catenin. Sox11 was transduced into rMSCs using lentiviruses. The expression levels of β-catenin and its downstream genes were evaluated by quantitative RT-PCR. The transcriptional activation of β-catenin was proved by dual-luciferase reporter assay and co-immunoprecipitation was performed to evaluate Sox11-β-catenin interaction. In addition, a cartilage defect model in SD rats was used to evaluate the cartilage regeneration ability of Sox11-modified rMSCs in vivo. We found that Sox11 transcriptionally activated β-catenin expression and discovered the core promoter region (from - 242 to - 1414) of β-catenin gene for Sox11 binding. In addition, Sox11 might regulate β-catenin at the post-transcriptional level by protein-protein interaction. Finally, using a cartilage defect model in rats, we found Sox11-modified rMSCs could improve cartilage regeneration. Taken together, our study shows that Sox11 is an important regulator of chondrogenesis and Sox11-modified rMSCs may have clinical implication for accelerating cartilage defect healing.
View details for DOI 10.1007/s00441-018-02979-4
View details for PubMedID 30617615
Synthetic presentation of noncanonical Wnt5a motif promotes mechanosensing-dependent differentiation of stem cells and regeneration
2019; 5 (10)
View details for DOI 10.1126/sciadv.aaw3896
Asiatic Acid Attenuates Bone Loss by Regulating Osteoclastic Differentiation
Calcified Tissue International
View details for DOI 10.1007/s00223-019-00596-z
Injectable stem cell-laden supramolecular hydrogels enhance in situ osteochondral regeneration via the sustained co-delivery of hydrophilic and hydrophobic chondrogenic molecules
View details for DOI 10.1016/j.biomaterials.2019.04.031
Lgr5-overexpressing mesenchymal stem cells augment fracture healing through regulation of Wnt/ERK signaling pathways and mitochondrial dynamics.
FASEB journal : official publication of the Federation of American Societies for Experimental Biology
Fracture remains one of the most common traumatic conditions in orthopedic surgery. The use of mesenchymal stem cells (MSCs) to augment fracture repair is promising. Leucine-rich repeat-containing GPCR 5 (Lgr5), a transmembrane protein, has been identified as a novel adult stem cell marker in various organs and tissues. However, the roles of Lgr5 in MSCs are not fully understood. In this study, we investigated cellular functions of Lgr5 in MSCs and its potential implications in treating fracture. Lgr5-overexpressing MSCs (MSCLgr5) were established in murine SV40 promoter-driven luciferase reporter MSC cell line through virus transfection. Results of real-time quantitative PCR and Western blot analysis confirmed the increased expression of Lgr5 in MSCLgr5. MSCLgr5 exhibited increased osteogenic capacity, which may result from elevated expression of β-catenin and phosphorylated ERK1/2 within the nuclei region of cells. In contrast, inhibition of Lgr5 expression decreased the osteogenic differentiation ability of MSCs, accompanied with increased mitochondrial fragmentation and reduced expression of β-catenin. Local transplantation of MSCLgr5 at fracture sites accelerated fracture healing via enhanced osteogenesis and angiogenesis. MSCLgr5 stimulated the tube formation capacity of HUVEC in a Matrigel coculture system in vitro significantly. Taken together, results suggest Lgr5 is implicated in the cellular processes of osteogenic differentiation of MSCs through regulation of Wnt and ERK signaling pathways and mitochondrial dynamics in fusion and fission. Inhibition of Lgr5 expression induced increased mitochondrial fragmentation and suppression of osteogenesis. MSCLgr5 exhibited enhanced therapeutic efficacy for fracture healing, which may serve as a superior cell source for bone tissue repair.-Lin, W., Xu, L., Pan, Q., Lin, S., Feng, L., Wang, B., Chen, S., Li, Y., Wang, H., Li, Y. C., Wang, Y., Lee, W. Y. W., Sun, D., Li, G. Lgr5-overexpressing mesenchymal stem cells augment fracture healing through regulation of Wnt/ERK signaling pathways and mitochondrial dynamics.
View details for DOI 10.1096/fj.201900082RR
View details for PubMedID 30991839
PLGA/β-TCP composite scaffold incorporating salvianolic acid B promotes bone fusion by angiogenesis and osteogenesis in a rat spinal fusion model.
2019; 196: 109–21
Spinal disorders often require surgical treatment called spinal fusion to restore a stabilized spine where bone grafts are implanted for the fusion of adjacent vertebras. In this study, we developed a bioactive composite scaffold incorporated with salvianolic acid B (SB), an active component extracted from Danshen. This study aimed to evaluate the effects of SB-incorporated porous scaffold on spinal fusion models. The composite scaffolds composed of poly (lactic-co-glycolic acid) and tricalcium phosphate (PLGA/β-TCP) were fabricated with low-temperature rapid prototyping technique, which incorporated SB at low (SB-L), middle (SB-M), high (SB-H) doses, and pure PLGA/β-TCP as blank control (Con). The release profile of SB from the scaffolds was determined by high performance liquid chromatography. Osteoconductive and osteoinductive properties of the scaffolds were reflected by the osteogenic differentiation ability of rat primary mesenchymal stem cells. The angiogenesis was determined by the forming of tube-like structures resembling capillaries using endothelial cell line (EA hy9.26). A well-established spinal fusion model was used to evaluate the in vivo bony fusion. Animals were transplanted with scaffolds, or autografts from iliac crest as positive controls. Micro-computed tomography (CT) analysis, CT-based angiography, manual palpation test, histomorphometry, and histology were performed after 8 weeks of transplantation. Results revealed that incorporated SB was steadily released from the scaffolds. The aliquot of released SB promoted osteogenesis and angiogenesis in vitro in a dose-dependent manner. In animal study, a dose-dependent effect of SB on new bone formation, mineral apposition rate, and vessel density within the scaffold were demonstrated. Manual palpation test showed little numerical improvement in fusion rate when compared with the blank controls. In summary, our results suggested that SB-incorporated PLGA/β-TCP composite scaffold could enhance bony fusion through the promotion of osteogenesis and angiogenesis.
View details for DOI 10.1016/j.biomaterials.2018.04.004
View details for PubMedID 29655516
Organic Semiconducting Polymer Nanoparticles for Photoacoustic Labeling and Tracking of Stem Cells in the Second Near-Infrared Window
2018; 12 (12): 12201–11
Photoacoustic (PA) imaging and tracking of stem cells plays an important role in the real-time assessment of cell-based therapies. Nevertheless, the limitations of conventional inorganic PA contrast agents and the narrow range of the excitation wavelength in the first near-infrared (NIR-I) window hamper the applications of PA imaging in living subjects. Herein, we report the design and synthesis of a second near-infrared (NIR-II) absorptive organic semiconducting polymer (OSP)-based nanoprobe (OSPN+) for PA imaging and tracking of stem cells. Comparison studies in biological tissue show that NIR-II light excited PA imaging of the OSPN+ has significantly higher signal-to-noise ratio than NIR-I light excited PA imaging, thereby demonstrating the superiority of the OSPN+ for deep tissue imaging. With good biocompatibility, appropriate size, and optimized surface property, the OSPN+ shows enhanced cellular uptake for highly efficient PA labeling of stem cells. In vivo investigations reveal significant NIR-II PA contrast enhancement of the transplanted OSPN+-labeled human mesenchymal stem cells by 40.6- and 21.7-fold in subcutaneous and brain imaging, respectively, compared with unlabeled cases. Our work demonstrates a class of OSP-based nanomaterials for NIR-II PA stem cell imaging to facilitate a better understanding and evaluation of stem cell-based therapies.
View details for DOI 10.1021/acsnano.8b05906
View details for Web of Science ID 000454567500045
View details for PubMedID 30433761
- Remote Control of Intracellular Calcium Using Upconversion Nanotransducers Regulates Stem Cell Differentiation In Vivo ADVANCED FUNCTIONAL MATERIALS 2018; 28 (41)
Ginsenoside Rb1 does not halt osteoporotic bone loss in ovariectomized rats
2018; 13 (9): e0202885
Osteoporosis (OP) is a systemic skeletal disorder, manifesting with a reduction in bone mass and deterioration of the microarchitecture. Mesenchymal stem cells (MSCs) have an innate ability to differentiate into several cell types, including osteoblasts (OB). Ginsenoside Rb1 (GRb1) is an ethanol extract from ginseng and contains a highly concentrated form of ginsenoside. GRb1 shows extensive beneficial health effects such as anti-oxidative and anti-inflammatory functions, modulating the immune system and inhibiting osteoclastogenesis. We hypothesized that GRb1 can promote MSC differentiation into OBs and inhibit bone loss. In the present study, we aimed to address two questions: (1) Will GRb1 have a positive effect on osteogenic differentiation of MSCs? and (2) Will GRb1 halt bone loss in ovariectomized (OVX) rats? We investigated the effects of GRb1 on viability and osteogenic differentiation of rat mesenchymal stem cells (rMSCs). Our results showed that GRb1 at concentrations of 10-8 M and 10-6 M can increase alkaline phosphatase activity, mineralization and the expression of osteogenic related proteins, such as osteopontin and osteoprotegerin, while incubating rMSCs with osteogenic induction medium and GRb1. Adding GRb1 into the medium can prevent rMSCs from Oxidative damage at the concentration of 25μM H2O2. Furthermore, 40 4-month-old rats were assigned to 5 groups(8 rats per group): the basal group, the sham group, the OVX group, the high dose of GRb1 group (6 mg/kg/day) and the low dose of GRb1 group (3 mg/kg/day). Rats recrived treatment 3days after surgery and last for 14 weeks. Examinations included serum analysis, mechanical testing, Masson-Goldner trichrome staining and bone histomorphometry analysis. The results showed that OVX can lead to dyslipidemia and excessive oxidative stress, whereas GRb1 cannot significantly halt dyslipidemia and excessive oxidative stress in OVX rats. In addition, the bone density of the lumbar vertebra and femur were decreased significantly in the OVX rats, and GRb1 could not inhibit bone loss. Bone histomorphometry analysis showed that the number and width of bone trabecula of the tibia were reduced in OVX rats, and GRb1 could not prevent their occurrence. A bone biomechanics assay showed that GRb1 cannot improve the ability of bone structure to resist fracture of the femur in OVX rats. The current study demonstrated that GRb1 has an obvious effect on osteogenic differentiation in rMSCs but no obvious effect on bone loss in OVX rats. These findings indicate GRb1 has a positive effect on rMSCs but does not have an effect on bone loss in OVX rats at the concentration we used.
View details for DOI 10.1371/journal.pone.0202885
View details for Web of Science ID 000444545800014
View details for PubMedID 30212470
View details for PubMedCentralID PMC6136715
GPR120 is an important inflammatory regulator in the development of osteoarthritis
ARTHRITIS RESEARCH & THERAPY
2018; 20: 163
The aim of this study was to investigate the regulatory role of G-protein coupled receptor 120 (GPR120) in the development and progression of osteoarthritis (OA).GPR120 knockout (KO) and wild-type (WT) mice were used to create an animal model of OA by means of anterior cruciate ligament transection (ACLT) surgery. The severity of OA was staged and evaluated by histological examination, microcomputed tomography scan and enzyme-linked immunosorbent assay (ELISA). The anti-inflammatory effects of the GPR120 agonist docosahexaenoic acid (DHA) on human chondrocytes were further evaluated by specific inflammatory markers. In addition, the healing progression of a skin defect model was determined with histological assays.The GPR120-KO mice displayed an accelerated development of OA after ACLT. The secondary inflammation, cartilage degeneration, and subchondral bone aberrant changes were significantly elevated in the early phase of OA in KO mice relative to those in WT mice. In addition, we found that GPR120 levels were downregulated in OA patients compared with control subjects, whereas GPR120 activation with DHA exhibited anti-inflammatory effects in primary human chondrocytes in vitro. Moreover, results from the skin defect model showed that GPR120 agonism with DHA enhanced wound repair in mice, as shown by the downregulation of the number of CD68+ cells.Our study suggests that GPR120 is an important inflammatory mediator during the development of OA, and that it is a potential marker for the diagnosis of high-risk patients with OA.
View details for DOI 10.1186/s13075-018-1660-6
View details for Web of Science ID 000441209200002
View details for PubMedID 30075737
View details for PubMedCentralID PMC6091098
Remote Control of Heterodimeric Magnetic Nanoswitch Regulates the Adhesion and Differentiation of Stem Cells
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
2018; 140 (18): 5909–13
Remote, noninvasive, and reversible control over the nanoscale presentation of bioactive ligands, such as Arg-Gly-Asp (RGD) peptide, is highly desirable for temporally regulating cellular functions in vivo. Herein, we present a novel strategy for physically uncaging RGD using a magnetic field that allows safe and deep tissue penetration. We developed a heterodimeric nanoswitch consisting of a magnetic nanocage (MNC) coupled to an underlying RGD-coated gold nanoparticle (AuNP) via a long flexible linker. Magnetically controlled movement of MNC relative to AuNP allowed reversible uncaging and caging of RGD that modulate physical accessibility of RGD for integrin binding, thereby regulating stem cell adhesion, both in vitro and in vivo. Reversible RGD uncaging by the magnetic nanoswitch allowed temporal regulation of stem cell adhesion, differentiation, and mechanosensing. This physical and reversible RGD uncaging utilizing heterodimeric magnetic nanoswitch is unprecedented and holds promise in the remote control of cellular behaviors in vivo.
View details for DOI 10.1021/jacs.8b03001
View details for Web of Science ID 000432091700008
View details for PubMedID 29681155
- Bioadhesive Polymersome for Localized and Sustained Drug Delivery at Pathological Sites with Harsh Enzymatic and Fluidic Environment via Supramolecular Host-Guest Complexation SMALL 2018; 14 (7)
Magnetic Manipulation of Reversible Nanocaging Controls In Vivo Adhesion and Polarization of Macrophages.
Macrophages are key immune cells that perform various physiological functions, such as the maintenance of homeostasis, host defense, disease progression, and tissue regeneration. Macrophages adopt distinctly polarized phenotypes, such as pro-inflammatory M1 phenotype or anti-inflammatory (pro-healing) M2 phenotype, to execute disparate functions. The remotely controlled reversible uncaging of bioactive ligands, such as Arg-Gly-Asp (RGD) peptide, is an appealing approach for temporally regulating the adhesion and resultant polarization of macrophages on implants in vivo. Here, we utilize physical and reversible uncaging of RGD by a magnetic field that allows facile tissue penetration. We first conjugated a RGD-bearing gold nanoparticle (GNP) to the substrate and then a magnetic nanocage (MNC) to the GNP via a flexible linker to form the heterodimeric nanostructure. We magnetically manipulated nanoscale displacement of MNC and thus its proximity to the GNP to reversibly uncage and cage RGD. The uncaging of RGD temporally promoted the adhesion and subsequent M2 polarization of macrophages while inhibiting their M1 polarization both in vitro and in vivo. The RGD uncaging-mediated adhesion and M2 polarization of macrophages involved rho-associated protein kinase signaling. This study demonstrates physical and reversible uncaging of RGD to regulate the adhesion and polarization of host macrophages in vivo. This approach of magnetically regulating the heterodimer conformation for physical and reversible uncaging of RGD offers the promising potential to manipulate inflammatory or tissue-regenerative immune responses to the implants in vivo.
View details for DOI 10.1021/acsnano.8b02226
View details for PubMedID 29767957
Nanolayered hybrid mediates synergistic co-delivery of ligand and ligation activator for inducing stem cell differentiation and tissue healing
2017; 149: 12–28
Cellular behaviors, such as differentiation, are regulated by complex ligation processes involving cell surface receptors, which can be activated by various divalent metal cations. The design of nanoparticle for co-delivery of ligand and ligation activator can offer a novel strategy to synergistically stimulate ligation processes in vivo. Here, we present a novel layered double hydroxide (LDH)-based nanohybrid (MgFe-Ado-LDH), composed of layered MgFe hydroxide nanocarriers sandwiching the adenosine cargo molecule, maintained through an electrostatic balance, to co-deliver the adenosine (Ado) ligand from the interlayer spacing and the Mg2+ ion (ligation activator) through the dissolution of the MgFe nanocarrier itself. Our findings demonstrate that the MgFe-Ado-LDH nanohybrid promoted osteogenic differentiation of stem cells through the synergistic activation of adenosine A2b receptor (A2bR) by the dual delivery of adenosine and Mg2+ ions, outperforming direct supplementation of adenosine alone. Furthermore, the injection of the MgFe-Ado-LDH nanohybrid and stem cells embedded within hydrogels promoted the healing of rat tibial bone defects through the rapid formation of fully integrated neo-bone tissue through the activation of A2bR. The newly formed bone tissue displayed the key features of native bone, including calcification, mature tissue morphology, and vascularization. This study demonstrates a novel and effective strategy of bifunctional nanocarrier-mediated delivery of ligand (cargo molecule) and activation of its ligation to receptor by the nanocarrier itself for synergistically inducing stem cell differentiation and tissue healing in vivo, thus offering novel design of biomaterials for regenerative medicine.
View details for DOI 10.1016/j.biomaterials.2017.09.035
View details for Web of Science ID 000414815700002
View details for PubMedID 28988061
Nanocomposite hydrogels stabilized by self-assembled multivalent bisphosphonate-magnesium nanoparticles mediate sustained release of magnesium ion and promote in-situ bone regeneration
2017; 64: 389–400
Hydrogels are appealing biomaterials for applications in regenerative medicine due to their tunable physical and bioactive properties. Meanwhile, therapeutic metal ions, such as magnesium ion (Mg2+), not only regulate the cellular behaviors but also stimulate local bone formation and healing. However, the effective delivery and tailored release of Mg2+ remains a challenge, with few reports on hydrogels being used for Mg2+ delivery. Bisphosphonate exhibits a variety of specific bioactivities and excellent binding affinity to multivalent cations such as Mg2+. Herein, we describe a nanocomposite hydrogel based on hyaluronic acid and self-assembled bisphosphonate-magnesium (BP-Mg) nanoparticles. These nanoparticles bearing acrylate groups on the surface not only function as effective multivalent crosslinkers to strengthen the hydrogel network structure, but also promote the mineralization of hydrogels and mediate sustained release of Mg2+. The released Mg2+ ions facilitate stem cell adhesion and spreading on the hydrogel substrates in the absence of cell adhesion ligands, and promote osteogenesis of the seeded hMSCs in vitro. Furthermore, the acellular porous hydrogels alone can support in situ bone regeneration without using exogenous cells and inductive agents, thereby greatly simplifying the approaches of bone regeneration therapy.In this study, we developed a novel bioactive nanocomposite hydrogel based on hyaluronic acid and self-assembled bisphosphonate-magnesium (BP-Mg) nanoparticles. Such hydrogels are stabilized by the multivalent crosslinking domains formed by the aggregation of Ac-BP-Mg NPs, and therefore show enhanced mechanical properties, improved capacity for mineralization, and controlled release kinetics of Mg2+. Moreover, the released Mg2+ can enhance cell adhesion and spreading, and further promote the osteogenic differentiation of hMSCs. Owing to these unique properties, these acellular hydrogels alone can well facilitate the in vivo bone regeneration at the intended sites. We believe that the strategy reported in this work opens up a new route to develop biopolymer-based nanocomposite hydrogels with enhanced physical and biological functionalities for regenerative medicine.
View details for DOI 10.1016/j.actbio.2017.09.039
View details for Web of Science ID 000416498200034
View details for PubMedID 28963020
Dysregulation of both miR-140-3p and miR-140-5p in synovial fluid correlate with osteoarthritis severity
BONE & JOINT RESEARCH
2017; 6 (11): 612–18
This study looked to analyse the expression levels of microRNA-140-3p and microRNA-140-5p in synovial fluid, and their correlations to the severity of disease regarding knee osteoarthritis (OA).Knee joint synovial fluid samples were collected from 45 patients with OA of the knee (15 mild, 15 moderate and 15 severe), ten healthy volunteers, ten patients with gouty arthritis, and ten with rheumatoid arthritis. The Kellgren-Lawrence grading (KLG) was used to assess the radiological severity of knee OA, and the patients were stratified into mild (KLG < 2), moderate (KLG = 2), and severe (KLG > 2). The expression of miR-140-3p and miR-140-5p of individual samples was measured by SYBR Green quantitative polymerase chain reaction (PCR) analysis. The expression of miR-140-3p and miR-140-5p was normalised to U6 internal control using the 2-△△CT method. All data were processed using SPSS software.Expression of both miR-140-3p and miR-140-5p was downregulated in OA synovial fluid, showing a statistical difference between the OA and non-OA group, and increased OA severity was associated with a decreased expression of miR-140-3p or miR-140-5p. The Spearman rank correlation analysis suggested that the expression of miR-140-3p or miR-140-5p was negatively correlated with OA severity. In addition, the expression of miR-140-5p was 7.4 times higher than that of miR-140-3p across all groups.The dysregulation of miR-140-3p and miR-140-5p in synovial fluid and their correlations with the disease severity of OA may provide an important experimental basis for OA classification, and the miR-140-3p/miR-140-5p are of great potential as biomarkers in the diagnosis and clinical management of patients with OA.Cite this article: C-M. Yin, W-C-W. Suen, S. Lin, X-M. Wu, G. Li, X-H. Pan. Dysregulation of both miR-140-3p and miR-140-5p in synovial fluid correlate with osteoarthritis severity. Bone Joint Res 2017;6:612-618. DOI: 10.1302/2046-3758.611.BJR-2017-0090.R1.
View details for DOI 10.1302/2046-3758.611
View details for Web of Science ID 000416554700001
View details for PubMedID 29092816
View details for PubMedCentralID PMC5717073
Synergistic effects on mesenchymal stem cell-based cartilage regeneration by chondrogenic preconditioning and mechanical stimulation
STEM CELL RESEARCH & THERAPY
2017; 8: 221
Mesenchymal stem cells (MSCs) hold promising translational potential in cartilage regeneration. However, the efficacy of MSC-based tissue engineering is not satisfactory in the treatment of cartilage defect because of the inevitable cellular functional changes during ex vivo cell expansion. How to maintain the chondrogenic capacity of MSCs to improve their therapeutic outcomes remains an outstanding question.Bone marrow-derived MSCs were firstly primed in chondrogenic induction medium which was then replaced with normal growth medium to attain the manipulated cells (M-MSCs). Methacrylated hyaluronic acid (MeHA) was synthesized as a scaffold to encapsulate the cells. The MSC- or M-MSC-laden constructs were treated with dynamic compressive loading (DL) in a bioreactor or with free loading (FL) for 14 days. Afterwards, the constructs were implanted in nude mice or rat models of osteochondral defects to test their efficiency in cartilage regeneration or repair.Data showed that the resulting M-MSCs exhibited superior chondrogenic differentiation potential and survivability compared with untreated MSCs. More importantly, we found that DL significantly promoted neocartilage formation in the MeHA hydrogel encapsulated with M-MSCs after 30 days of implantation in nude mice. Furthermore, the constructs laden with M-MSCs after DL for 14 days significantly enhanced cartilage healing in a rat model of osteochondral defect.Findings from this study highlight the importance of maintaining chondrogenic potential of MSCs by in-vitro chondrogenic preconditioning and a synergistic effect of mechanical stimulation in cartilage engineering, which may shed light on the stem cell-based tissue engineering for cartilage repair.
View details for DOI 10.1186/s13287-017-0672-5
View details for Web of Science ID 000412196100004
View details for PubMedID 28974254
View details for PubMedCentralID PMC5627486
Remote Manipulation of Ligand Nano-Oscillations Regulates Adhesion and Polarization of Macrophages in Vivo
2017; 17 (10): 6415–27
Macrophages play crucial roles in various immune-related responses, such as host defense, wound healing, disease progression, and tissue regeneration. Macrophages perform distinct and dynamic functions in vivo, depending on their polarization states, such as the pro-inflammatory M1 phenotype and pro-healing M2 phenotype. Remote manipulation of the adhesion of host macrophages to the implants and their subsequent polarization in vivo can be an attractive strategy to control macrophage polarization-specific functions but has rarely been achieved. In this study, we grafted RGD ligand-bearing superparamagnetic iron oxide nanoparticles (SPIONs) to a planar matrix via a long flexible linker. We characterized the nanoscale motion of the RGD-bearing SPIONs grafted to the matrix, in real time by in situ magnetic scanning transmission electron microscopy (STEM) and in situ atomic force microscopy. The magnetic field was applied at various oscillation frequencies to manipulate the frequency-dependent ligand nano-oscillation speeds of the RGD-bearing SPIONs. We demonstrate that a low oscillation frequency of the magnetic field stimulated the adhesion and M2 polarization of macrophages, whereas a high oscillation frequency suppressed the adhesion of macrophages but promoted their M1 polarization, both in vitro and in vivo. Macrophage adhesion was also temporally regulated by switching between the low and high frequencies of the oscillating magnetic field. To the best of our knowledge, this is the first demonstration of the remote manipulation of the adhesion and polarization phenotype of macrophages, both in vitro and in vivo. Our system offers the promising potential to manipulate host immune responses to implanted biomaterials, including inflammation or tissue reparative processes, by regulating macrophage adhesion and polarization.
View details for DOI 10.1021/acs.nanolett.7b03405
View details for Web of Science ID 000413057500078
View details for PubMedID 28875707
Tenomodulin highly expressing MSCs as a better cell source for tendon injury healing
2017; 8 (44): 77424–35
Tendon injuries are common orthopedic problems which may cause severe morbidity. MSCs (mesenchymal stem cells) have shown promising effect on tissue engineering and have been used for the treatment of tendon injury. But the low tenogenic differentiation capacity of MSCs have hindered their application. In the present study, we have constructed the Tenomodulin (Tnmd) promoter-driven GFP expression lentiviral plasmid. After transduced into BMSCs, the expression of GFP was used to select BMSCs highly expressing Tnmd by flow cytometry. We found that MSCs with higher level of Tnmd expression had stronger tenogenic differentiation ability. Furthermore, RNA sequencing was performed to identify the molecular difference between BMSCs expressing higher and lower levels of Tnmd. And finally we demonstrated that GDF7 was upregulated in BMSCs highly expressing Tnmd and played an vital role in promoting tenogenic differentiation of BMSCs. GDF7 was mainly accounted for the elevated tenogenic differentiation ability of BMSCs with higher Tnmd expression as silencing the endogenous GDF7 significantly inhibited tenogenesis in BMSCs. In addition, the effect of BMSCs with higher Tnmd level on tendon healing was evaluated by a rat patellar tendon injury model. Taken together, our study showed that Tnmd could be used as an ideal cell surface marker to select cells with higher tenogenic differentiation ability from BMSCs, and GDF7 was indispensable for tenogenesis of MSCs.
View details for DOI 10.18632/oncotarget.20495
View details for Web of Science ID 000412066700131
View details for PubMedID 29100398
View details for PubMedCentralID PMC5652790
Stepwise preconditioning enhances mesenchymal stem cell-based cartilage regeneration through epigenetic modification
OSTEOARTHRITIS AND CARTILAGE
2017; 25 (9): 1541–50
This study is to investigate the functions and underlying mechanisms of mesenchymal stem cells (MSCs) underwent stepwise preconditioning in chondrogenic medium before expansion, then further explore their therapeutic effects in a surgically induced osteoarthritis (OA) model.MSCs isolated from the adult rats expressing Green Fluorescence Protein (GFP) were incubated in basal medium or primed in chondrogenic medium before expansion. The multipotency including cell proliferation, differentiation, and survivability was compared between chondrogenic manipulated MSCs (M-MSCs) and untreated MSCs. Methylation modification of Nanog and Oct4 were detected by bisulfite genomic sequencing. Loss-of-function phenotype in M-MSCs induced by shNanog was also observed. Then the therapeutic effect of the cells was evaluated in a surgically induced OA rat model by single intraarticular injection. The injected GFP-labeled cells in the joints were monitored in vivo. These rats were sacrificed and subjected to histological examinations and microstructural analysis after 4 weeks.We found that cell clonogenicity, proliferation, survivability, and chondrogenic property were enhanced after stepwise preconditioning. We then further found that the expression level of Nanog and Oct4 was temporarily increased in the M-MSCs. Results of epigenetic analysis revealed that demethylation happened in Nanog and Oct4 after the stepwise preconditioning. Results of in vivo imaging showed more GFP-labeled cells in the M-MSCs-injected group. And results of histology and micro-CT analysis also indicated a superior therapeutic effect of M-MSCs on the surgically induced-OA.These findings indicated a feasible method to obtain a cell population with high survivability and chondrogenic commitment for the treatment of OA.
View details for DOI 10.1016/j.joca.2017.05.008
View details for Web of Science ID 000407934000021
View details for PubMedID 28545880
Stem cell therapy for enhancement of bone consolidation in distraction osteogenesis
BONE & JOINT RESEARCH
2017; 6 (6): 385–90
Distraction osteogenesis (DO) mobilises bone regenerative potential and avoids the complications of other treatments such as bone graft. The major disadvantage of DO is the length of time required for bone consolidation. Mesenchymal stem cells (MSCs) have been used to promote bone formation with some good results.We hereby review the published literature on the use of MSCs in promoting bone consolidation during DO.Studies differed in animal type (mice, rabbit, dog, sheep), bone type (femur, tibia, skull), DO protocols and cell transplantation methods.The majority of studies reported that the transplantation of MSCs enhanced bone consolidation or formation in DO. Many questions relating to animal model, DO protocol and cell transplantation regime remain to be further investigated. Clinical trials are needed to test and confirm these findings from animal studies.Cite this article: Y. Yang, S. Lin, B. Wang, W. Gu, G. Li. Stem cell therapy for enhancement of bone consolidation in distraction osteogenesis: A contemporary review of experimental studies. Bone Joint Res 2017;6:385-390. DOI: 10.1302/2046-3758.66.BJR-2017-0023.
View details for DOI 10.1302/2046-3758.66.BJR-2017-0023
View details for Web of Science ID 000404265300004
View details for PubMedID 28634158
View details for PubMedCentralID PMC5492338
Sulfated hyaluronic acid hydrogels with retarded degradation and enhanced growth factor retention promote hMSC chondrogenesis and articular cartilage integrity with reduced hypertrophy
2017; 53: 329–42
Recently, hyaluronic acid (HA) hydrogels have been extensively researched for delivering cells and drugs to repair damaged tissues, particularly articular cartilage. However, the in vivo degradation of HA is fast, thus limiting the clinical translation of HA hydrogels. Furthermore, HA cannot bind proteins with high affinity because of the lack of negatively charged sulfate groups. In this study, we conjugated tunable amount of sulfate groups to HA. The sulfated HA exhibits significantly slower degradation by hyaluronidase compared to the wild type HA. We hypothesize that the sulfation reduces the available HA octasaccharide substrate needed for the effective catalytic action of hyaluronidase. Moreover, the sulfated HA hydrogels significantly improve the protein sequestration, thereby effectively extending the availability of the proteinaceous drugs in the hydrogels. In the following in vitro study, we demonstrate that the HA hydrogel sulfation exerts no negative effect on the viability of encapsulated human mesenchymal stem cells (hMSCs). Furthermore, the sulfated HA hydrogels promote the chondrogenesis and suppresses the hypertrophy of encapsulated hMSCs both in vitro and in vivo. Moreover, intra-articular injections of the sulfated HA hydrogels avert the cartilage abrasion and hypertrophy in the animal osteoarthritic joints. Collectively, our findings demonstrate that the sulfated HA is a promising biomaterial for the delivery of therapeutic agents to aid the regeneration of injured or diseased tissues and organs.In this paper, we conjugated sulfate groups to hyaluronic acid (HA) and demonstrated the slow degradation and growth factor delivery of sulfated HA. Furthermore, the in vitro and in vivo culture of hMSCs laden HA hydrogels proved that the sulfation of HA hydrogels not only promotes the chondrogenesis of hMSCs but also suppresses hypertrophic differentiation of the chondrogenically induced hMSCs. The animal OA model study showed that the injected sulfated HA hydrogels significantly reduced the cartilage abrasion and hypertrophy in the animal OA joints. We believe that this study will provide important insights into the design and optimization of the HA-based hydrogels as the scaffold materials for cartilage regeneration and OA treatment in clinical setting.
View details for DOI 10.1016/j.actbio.2017.02.015
View details for Web of Science ID 000401679100029
View details for PubMedID 28193542
Epigenetic Modification of the CCL5/CCR1/ERK Axis Enhances Glioma Targeting in Dedifferentiation-Reprogrammed BMSCs
STEM CELL REPORTS
2017; 8 (3): 743–57
The success of stem cell-mediated gene therapy in cancer treatment largely depends on the specific homing ability of stem cells. We have previously demonstrated that after in vitro induction of neuronal differentiation and dedifferentiation, bone marrow stromal cells (BMSCs) revert to a primitive stem cell population (De-neu-BMSCs) distinct from naive BMSCs. We report here that De-neu-BMSCs express significantly higher levels of chemokines, and display enhanced homing abilities to glioma, the effect of which is mediated by the activated CCL5/CCR1/ERK axis. Intriguingly, we find that the activated chemokine axis in De-neu-BMSCs is epigenetically regulated by histone modifications. On the therapeutic front, we show that De-neu-BMSCs elicit stronger homing and glioma-killing effects together with cytosine deaminase/5-fluorocytosine compared with unmanipulated BMSCs in vivo. Altogether, the current study provides an insight into chemokine regulation in BMSCs, which may have more profound effects on BMSC function and their application in regenerative medicine and cancer targeting.
View details for DOI 10.1016/j.stemcr.2017.01.016
View details for Web of Science ID 000397103900021
View details for PubMedID 28216148
View details for PubMedCentralID PMC5355636
Aspirin prevents bone loss with little mechanical improvement in high-fat-fed ovariectomized rats
EUROPEAN JOURNAL OF PHARMACOLOGY
2016; 791: 331–38
Obesity and osteoporosis are often concurrently happened in the menopausal women. Obesity in menopausal women is not only related to a high risk of cardiovascular disease, but also results in a detrimental effect on bone health. This study aimed to investigate the effects of aspirin, a popular anti-thrombosis drug, on bone quantity and quality in the high-fat-fed animal model. Adult female rats were subjected to either sham operations or ovariectomized operations. The ovariectomized rats were orally administered with deionized water or standardized high fat emulsion with or without aspirin. All rats were injected with calcein before killed for the purpose of double in vivo labeling. Biochemistry, histomorphometry, micro-computed tomography analysis, mechanical test, and component analysis were performed after 12 weeks. In vitro cell culture was also performed to observe the effect of aspirin in osteogenesis. We found that high fat remarkably impaired bone formation and bone biomechanics. Aspirin treatment significantly prevented bone loss by increasing bone formation. In vitro studies also validated the enhancement of osteogenic differentiation. However, aspirin presented no significant improvement in bone mechanical properties. Component analysis shown aspirin could significantly increase the content of mineral, but had limited effect on the content of collagen. In conclusion, aspirin is beneficial for the prevention of bone loss; meanwhile, it may cause an imbalance in the components of bone which may weaken the mechanical properties. The current study provided further evidence that aspirin might not be powerful for the prevention of fracture in osteoporotic patients.
View details for DOI 10.1016/j.ejphar.2016.09.018
View details for Web of Science ID 000388827700036
View details for PubMedID 27615444
Systemic Administration of Allogeneic Mesenchymal Stem Cells Does Not Halt Osteoporotic Bone Loss in Ovariectomized Rats
2016; 11 (10): e0163131
Mesenchymal stem cells (MSCs) have innate ability to self-renew and immunosuppressive functions, and differentiate into various cell types. They have become a promising cell source for treating many diseases, particular for bone regeneration. Osteoporosis is a common metabolic bone disorder with elevated systemic inflammation which in turn triggers enhanced bone loss. We hypothesize that systemic infusion of MSCs may suppress the elevated inflammation in the osteoporotic subjects and slow down bone loss. The current project was to address the following two questions: (1) Will a single dose systemic administration of allogenic MSCs have any effect on osteoporotic bone loss? (2) Will multiple administration of allogenic MSCs from single or multiple donors have similar effect on osteoporotic bone loss? 18 ovariectomized (OVX) rats were assigned into 3 groups: the PBS control group, MSCs group 1 (receiving 2x106 GFP-MSCs at Day 10, 46, 91 from the same donor following OVX) and MSCs group 2 (receiving 2x106 GFP-MSCs from three different donors at Day 10, 46, 91). Examinations included Micro-CT, serum analysis, mechanical testing, immunofluorescence staining and bone histomorphometry analysis. Results showed that BV/TV at Day 90, 135, BMD of TV and trabecular number at Day 135 in the PBS group were significantly higher than those in the MSCs group 2, whereas trabecular spacing at Day 90, 135 was significantly smaller than that in MSCs group 2. Mechanical testing data didn't show significant difference among the three groups. In addition, the ELISA assay showed that level of Rantes in serum in MSCs group 2 was significantly higher than that of the PBS group, whereas IL-6 and IL-10 were significantly lower than those of the PBS group. Bone histomorphometry analysis showed that Oc.S/BS and Oc.N/BS in the PBS group were significant lower than those in MSCs group 2; Ob.S/BS and Ob.N/BS did not show significant difference among the three groups. The current study demonstrated that systemic administration of allogenic MSCs had no obvious effect on osteoporotic bone loss in OVX rats when using the cells from the same donor; and repeated injection of allogeneic MSCs from different donors might promote bone loss in OVX rats. These findings indicate that despite allogenic MSCs systemic infusion is safe, their administration alone may not be an effective mean for preventing osteoporotic bone loss.
View details for DOI 10.1371/journal.pone.0163131
View details for Web of Science ID 000385697600014
View details for PubMedID 27711227
View details for PubMedCentralID PMC5053541
Mechanically resilient, injectable, and bioadhesive supramolecular gelatin hydrogels crosslinked by weak host-guest interactions assist cell infiltration and in situ tissue regeneration
2016; 101: 217–28
Although considered promising materials for assisting organ regeneration, few hydrogels meet the stringent requirements of clinical translation on the preparation, application, mechanical property, bioadhesion, and biocompatibility of the hydrogels. Herein, we describe a facile supramolecular approach for preparing gelatin hydrogels with a wide array of desirable properties. Briefly, we first prepare a supramolecular gelatin macromer via the efficient host-guest complexation between the aromatic residues of gelatin and free diffusing photo-crosslinkable acrylated β-cyclodextrin (β-CD) monomers. The subsequent crosslinking of the macromers produces highly resilient supramolecular gelatin hydrogels that are solely crosslinked by the weak host-guest interactions between the gelatinous aromatic residues and β-cyclodextrin (β-CD). The obtained hydrogels are capable of sustaining excessive compressive and tensile strain, and they are capable of quick self healing after mechanical disruption. These hydrogels can be injected in the gelation state through surgical needles and re-molded to the targeted geometries while protecting the encapsulated cells. Moreover, the weak host-guest crosslinking likely facilitate the infiltration and migration of cells into the hydrogels. The excess β-CDs in the hydrogels enable the hydrogel-tissue adhesion and enhance the loading and sustained delivery of hydrophobic drugs. The cell and animal studies show that such hydrogels support cell recruitment, differentiation, and bone regeneration, making them promising carrier biomaterials of therapeutic cells and drugs via minimally invasive procedures.
View details for DOI 10.1016/j.biomaterials.2016.05.043
View details for Web of Science ID 000379632500020
View details for PubMedID 27294539
Stepwise Differentiation of Mesenchymal Stem Cells Augments Tendon-Like Tissue Formation and Defect Repair In Vivo
STEM CELLS TRANSLATIONAL MEDICINE
2016; 5 (8): 1106–16
: Tendon injuries are common and present a clinical challenge, as they often respond poorly to treatment and result in long-term functional impairment. Inferior tendon healing responses are mainly attributed to insufficient or failed tenogenesis. The main objective of this study was to establish an efficient approach to induce tenogenesis of bone marrow-derived mesenchymal stem cells (BMSCs), which are the most common seed cells in tendon tissue engineering. First, representative reported tenogenic growth factors were used as media supplementation to induce BMSC differentiation, and the expression of teno-lineage transcription factors and matrix proteins was compared. We found that transforming growth factor (TGF)-β1 significantly induced teno-lineage-specific gene scleraxis expression and collagen production. TGF-β1 combined with connective tissue growth factor (CTGF) elevated tenomodulin and Egr1 expression at day 7. Hence, a stepwise tenogenic differentiation approach was established by first using TGF-β1 stimulation, followed by combination with CTGF for another 7 days. Gene expression analysis showed that this stepwise protocol initiated and maintained highly efficient tenogenesis of BMSCs. Finally, regarding in situ rat patellar tendon repair, tendons treated with induced tenogenic BMSCs had better structural and mechanical properties than those of the control group, as evidenced by histological scoring, collagen I and tenomodulin immunohistochemical staining, and tendon mechanical testing. Collectively, these findings demonstrate a reliable and practical strategy of inducing tenogenesis of BMSCs for tendon regeneration and may enhance the effectiveness of cell therapy in treating tendon disorders.The present study investigated the efficiency of representative tenogenic factors on mesenchymal stem cells' tenogenic differentiation and established an optimized stepwise tenogenic differentiation approach to commit tendon lineage differentiation for functional tissue regeneration. The reliable tenogenic differentiation approach for stem cells not only serves as a platform for further studies of underlying molecular mechanisms but also can be used to enhance cell therapy outcome in treating tendon disorders and develop novel therapeutics for tendon injury.
View details for DOI 10.5966/sctm.2015-0215
View details for Web of Science ID 000385288800012
View details for PubMedID 27280798
View details for PubMedCentralID PMC4954446
miRNA-29b improves bone healing in mouse fracture model
MOLECULAR AND CELLULAR ENDOCRINOLOGY
2016; 430 (C): 97–107
A number of miRNAs regulates bone remodeling and their levels in circulation were associated with bone fracture, however no miRNAs have yet been shown to improve fracture healing directly. This study aimed to investigate the effect of miR-29b-3p on mice femoral fracture healing through site-specific delivery with microbubble-ultrasound system. miR-29b-3p promoted osteogenesis of mouse bone marrow-derived mesenchymal stem cells as indicated with quantitative real-time polymerase chain reaction (qPCR) and Alizarin red S staining. Animal study showed that single injection of miR-29b-3p at week 2 post fracture improved healing outcome as indicated by significant decrease of callus width and area with radiographic analysis without causing significant weight loss. Static bone histomorphometry analysis showed that miR-29b-3p increased bone volume fraction (BV/TV), and micro-computed tomography (micro-CT) measurement showed increased BV/TV of high density bone and bone mineral density (BMD) of the callus. 3 point bending mechanical test showed improved relative stiffness. However, repeated injection of miR-29b-3p at weeks 2 and 3 did not result in additive therapeutic outcome, and caused increased total tissue volume and reduced BMD of the callus. This is the first report showing significant therapeutic effect of miR-29b-3p on femoral fracture healing through site-specific delivery with microbubble-ultrasound system. Further studies are warranted to investigate the underlying mechanisms and to refine the treatment protocol.
View details for DOI 10.1016/j.mce.2016.04.014
View details for Web of Science ID 000378457200010
View details for PubMedID 27113026
- Nanocarrier-Mediated Codelivery of Small Molecular Drugs and siRNA to Enhance Chondrogenic Differentiation and Suppress Hypertrophy of Human Mesenchymal Stem Cells ADVANCED FUNCTIONAL MATERIALS 2016; 26 (15): 2463–72
- Robust Biopolymeric Supramolecular "Host-Guest Macromer" Hydrogels Reinforced by in Situ Formed Multivalent Nanoclusters for Cartilage Regeneration MACROMOLECULES 2016; 49 (3): 866–75
Hydrogels functionalized with N-cadherin mimetic peptide enhance osteogenesis of hMSCs by emulating the osteogenic niche
2016; 77: 44–52
N-cadherin is considered to be the key factor in directing cell-cell interactions during mesenchymal condensation, which is essential to osteogenesis. In this study, hyaluronic acid (HA) hydrogels are biofunctionalized with an N-cadherin mimetic peptide to mimic the pro-osteogenic niche in the endosteal space to promote the osteogenesis of human mesenchymal stem cells (hMSCs). Results show that the conjugation of the N-cadherin peptide in the HA hydrogels enhances the expression of the osteogenic marker genes in the seeded hMSCs. Furthermore, the biofunctionalized HA hydrogels promote the alkaline phosphatase activity, type I collagen deposition, and matrix mineralization by the seeded hMSCs under both in vitro and in vivo condition. We postulate that the biofunctionalized hydrogels emulates the N-cadherin-mediated homotypic cell-cell adhesion among MSCs and the "orthotypic" interaction between the osteoblasts and MSCs. These findings demonstrate that the biofunctionalized HA hydrogels provide a supportive niche microenvironment for the osteogenesis of hMSCs.
View details for DOI 10.1016/j.biomaterials.2015.10.072
View details for Web of Science ID 000367118200004
View details for PubMedID 26580785
- Antler Collagen/Chitosan Scaffolds Improve Critical Calvarial Defect Healing in Rats JOURNAL OF BIOMATERIALS AND TISSUE ENGINEERING 2015; 5 (10): 774–79
Epigenetic memory gained by priming with osteogenic induction medium improves osteogenesis and other properties of mesenchymal stem cells
2015; 5: 11056
Mesenchymal stem cells (MSCs) are highly plastic cells that are able to transdifferentiate or dedifferentiate under appropriate conditions. In the present study, we reported here that after in vitro induction of osteogenic differentiation, MSCs could be reverted to a primitive stem cell population (dedifferentiated osteogenic MSCs, De-Os-MSCs) with improved cell survival, colony formation, osteogenic potential, migratory capacity and increased expression of Nanog, Oct4 and Sox2. Most importantly, our results showed great superiority of the De-Os-MSCs over untreated MSCs in ectopic bone formation in vivo. Furthermore, Nanog-knockdown in MSCs could reverse these enhanced properties in De-Os-MSCs in vitro, indicating a central role of Nanog in the transcriptional network. In addition, epigenetic regulations including DNA methylation and histone modifications may play important roles in regulating the de-osteogenic differentiation process. And we found decreased methylation and promoter accrual of activating histone marks, such as H3K4me3 and H4ac on both Nanog and Oct4 gene promoters. Taken together, our study demonstrated that epigenetic memory in De-Os-MSCs gained by priming with osteogenic induction medium favored their differentiation along osteoblastic lineage with improved cell survival and migratory abilities, which may have application potential in enhancing their regenerative capacity in mammals.
View details for DOI 10.1038/srep11056
View details for Web of Science ID 000356069300001
View details for PubMedID 26053250
View details for PubMedCentralID PMC4459169
The Effects of Atorvastatin on the Prevention of Osteoporosis and Dyslipidemia in the High-Fat-Fed Ovariectomized Rats
CALCIFIED TISSUE INTERNATIONAL
2015; 96 (6): 541–51
Previous studies reported that statins showed positive effects on bone in both human and animal models. This study aimed to investigate the effects of atorvastatin on the prevention of osteoporosis and dyslipidemia in ovariectomized rats fed with high-fat emulsion. The 3-month-old female rats were subjected to either sham operations (n = 8) or ovariectomized operations (OVX, n = 24). The OVX rats were orally administered deionized water (n = 8) or standardized high-fat emulsion without (n = 8) or with atorvastatin (n = 8). All rats were injected twice with calcein before sacrificed for the purpose of double in vivo labeling. After 12 weeks, all rats were sacrificed under anesthesia. Biochemistry, histomorphometry, mechanical test, micro-computed tomography analysis, mechanical test, histology, and component analysis were performed. We found that high-fat emulsion significantly decreased body weight, bone formation, collagen content of bone, and bone biomechanics, while increased blood, liver, and bone marrow lipids. Atorvastatin treatment prevented dyslipidemia, reversed hepatic steatosis, optimized composition of bone, and improved bone mechanical properties. The current study provided further evidence that atorvastatin might be useful for the treatment of osteoporotic patients with dyslipidemia.
View details for DOI 10.1007/s00223-015-9975-7
View details for Web of Science ID 000354704100008
View details for PubMedID 25814468
Three-dimensional CaP/gelatin lattice scaffolds with integrated osteoinductive surface topographies for bone tissue engineering
2015; 7 (1): 015005
Surface topography is known to influence stem cells and has been widely used as physical stimuli to modulate cellular behaviour including adhesion, proliferation and differentiation on 2D surfaces. Integration of well-defined surface topography into three-dimensional (3D) scaffolds for tissue engineering would be useful to direct the cell fate for intended applications. Technical challenges are remaining as how to fabricate such 3D scaffolds with controlled surface topography from a range of biodegradable and biocompatible materials. In this paper, a novel fabrication process using computer numerically controlled machining and lamination is reported to make 3D calcium phosphate/gelatin composite scaffolds with integrated surface micropatterns that are introduced by embossing prior to machining. Geometric analysis shows that this method is versatile and can be used to make a wide range of lattices with porosities that meet the basic requirements for bone tissue engineering. Both in vitro and in vivo studies show that micropatterned composite scaffolds with surfaces comprising 40 μm pits and 50 μm grooves were optimal for improved osteogenesis. The results have demonstrated the potential of a novel fabrication process for producing cell-instructive scaffolds with designed surface topographies to induce specific tissue regeneration.
View details for DOI 10.1088/1758-5090/7/1/015005
View details for Web of Science ID 000353341000006
View details for PubMedID 25562325
U0126 promotes osteogenesis of rat bone-marrow-derived mesenchymal stem cells by activating BMP/Smad signaling pathway
CELL AND TISSUE RESEARCH
2015; 359 (2): 537–45
U0126 has been reported as a specific inhibitor of the ERK1/2 signaling pathway, which plays a vital role during the osteogenic differentiation of mesenchymal stem cells (MSCs). We report the positive effect of U0126 on the osteogenesis of rat MSCs. We find that U0126 promotes the osteogenic differentiation of rat MSCs as demonstrated by the quantitative real-time polymerase chain reaction for osteogenic markers, alkaline phosphatase activity and calcium nodule formation. Our data indicate that U0126 enhances the BMP/Smad signaling pathway in rat MSCs, while inhibiting the ERK1/2 signaling pathway. Furthermore, Western blot results demonstrate that U0126 increases Smad1/5/8 phosphorylation synergistically with β-glycerophosphate. In addition, U0126 significantly increases the expression of BMP2 during the process of osteogenesis in rat MSCs and the level of phosphorylated Smad1/5/8 is significantly reduced by BMP2 antibody, suggesting that U0126 also promotes the expression of BMP2 to enhance Smad proteins phosphorylation. Thus, we demonstrate a novel function for U0126 in promoting osteogenic differentiation of rat MSCs by the activation of the BMP/Smad signaling pathway.
View details for DOI 10.1007/s00441-014-2025-3
View details for Web of Science ID 000349240600014
View details for PubMedID 25363751
Glucocorticoid-Induced Osteoporosis in Growing Rats
CALCIFIED TISSUE INTERNATIONAL
2014; 95 (4): 362–73
This study evaluated whether growing rats were appropriate animal models of glucocorticoid-induced osteoporosis. The 3-month-old male rats were treated with either vehicle or prednisone acetate at 1.5, 3.0, and 6.0 mg/kg/day by oral gavage, respectively. All rats were injected with tetracycline and calcein before sacrificed for the purpose of double in vivo labeling. Biochemistry, histomorphometry, mechanical test, densitometry, micro-CT, histology, and component analysis were performed. We found that prednisone treatments dose dependently decreased body weight, serum biomarkers, biomechanical markers, bone formation, and bone resorption parameters in both tibial and femoral trabecular bone without trabecular bone loss. We also found that significant bone loss happened in femoral cortical bone in the glucocorticoid-treated rats. The results suggested that prednisone not only inhibited bone formation, but also inhibited bone resorption which resulted in poor bone strength but with no cancellous bone loss in growing rats. These data also suggested that the effects of glucocorticoid on bone metabolism were different between cortical bone and trabecular bone, and different between tibia and femur. Growing rats may be a glucocorticoid-induced osteoporosis animal model when evaluated the effects of drugs upon juvenile patients exposed to GC for a long time.
View details for DOI 10.1007/s00223-014-9899-7
View details for Web of Science ID 000342146500008
View details for PubMedID 25086673
Partial loss of Smad7 function impairs bone remodeling, osteogenesis and enhances osteoclastogenesis in mice
2014; 67: 46–55
Smad7 is well demonstrated as a negative regulator of TGF-β signaling. Its alteration in expression often results in diseases such as cancer and fibrosis. However, the exact role of Smad7 in regulating bone remodeling during mammalian development has not been properly delineated. In this study we performed experiments to clarify the involvement of Smad7 in regulating osteogenesis and osteoclastogenesis both invivo and invitro. Genetically engineered Smad7(ΔE1) (KO) mice were used, whereby partial functional of Smad7 is lost by deleting exon I of the Smad7 gene and the truncated proteins cause a hypomorphic allele. Analysis with μCT imagery and bone histomorphometry showed that the KO mice had lower TbN, TbTh, higher TbSp in the metaphysic region of the femurs at 6, 12, 24weeks from birth, as well as decreased MAR and increased osteoclast surface compared with the WT mice. In vitro BM-MSC multi-lineage differentiation evaluation showed that the KO group had reduced osteogenic potential, fewer mineralized nodules, lower ALP activity, and reduced gene expression of Col1A1, Runx2 and OCN. The adipogenic potential was elevated in the KO group with more formation of lipid droplets, and increased gene expression of Adipsin and C/EBPα. The osteoclastogenic potential of KO mice BMMs was elevate, with emergence of more osteoclasts, larger resorptive areas, and increased gene expression of TRAP and CTR. Our results indicate that partial loss of Smad7 function in mice leads to compromised bone formation and enhanced bone resorption. Thus, Smad7 is acknowledged as a novel key regulator between osteogenesis and osteoclastogenesis.
View details for DOI 10.1016/j.bone.2014.06.033
View details for Web of Science ID 000341227800007
View details for PubMedID 24998669
Prevention of Osteopenia and Dyslipidemia in Rats after Ovariectomy with Combined Aspirin and Low-dose Diethylstilbestrol
BIOMEDICAL AND ENVIRONMENTAL SCIENCES
2013; 26 (4): 249–57
To study whether effect of aspirin plus low-dose diethylstilbestrol is more effective and safer than high diethylstilbestrol dose alone on prevention of ovariectomy-induced osteopenia and dyslipidemia.Thirty-eight 4-month-old female SD rats were divided into baseline (BAS) group (n=6), sham operation group (n=8) and ovariectomy (OVX) group (n=24). The OVX group was further divided into vehicle treatment group (n=8), diethylstilbestrol (30 μg/kg•d) treatment group (OVX+D30 group, n=8), and aspirin (9 mg/kg•d) plus diethylstilbestrol (10 μg/kg•d) treatment group (OVX+A-D10 group, n=8). Their left tibiae were collected for the bone histomorphometric analysis in undecalcified sections. Left femurs were collected for the bone mineral density measurement.The body weight and serum cholesterol were increased, while uterine weight and cancellous bone mass were decreased in OVX rats compared with the SHAM group. Cancellous bone mass was significantly increased, while body weight and bone resorption parameters were decreased in both A-D10 and D30 treatment group compared with OVX group. The rats treated with A-D10 showed significantly increased in bone formation parameters and decreased in serum triglyceride compared with the D30-treated rats.Aspirin plus low-dose diethylstilbestrol can effectively prevent osteopenia by reducing bone resorption, and is thus a better treatment modality for preventing dyslipidemia than high-dose diethylstilbestrol alone.
View details for DOI 10.3967/0895-3988.2013.04.003
View details for Web of Science ID 000317968400003
View details for PubMedID 23534465