Highly ordered ring-like structures are formed via the directed assembly of lipid domains in supported bilayers, using the extracellular matrix protein fibronectin. The ability of biological molecules to guide nanoscale assembly suggests potential biomimetic approaches to nanoscale structures.
Human embryonic stem cells (hESc) are known for its pluripotency and self renewal capability, thus possess great potential in regenerative medicine. However, the lack of suitable xenofree extracellular matrix substrate inhibits further applications or the use of hESc in cell-based therapy. In this study, we described a new differentiation method, which generates a homogeneous population of mesenchymal progenitor cells (hESc-MPC) from hESc via epithelial-mesenchymal transition. The extracellular matrix (ECM) proteins from hESc-MPC had in turn supported the undifferentiated expansion of hESc. Immunocytochemistry and flow cytometry characterization of hESc-MPC revealed the presence of early mesenchymal markers. Tandem mass spectometry analysis of ECM produced by hESc-MPC revealed the presence of a mixture of extracellular proteins which includes tenascin C, fibronectin, and vitronectin. The pluripotency of hESc (MEL-1) cultured on the ECM was maintained as shown by the expression of pluripotent genes (FoxD3, Oct-4, Tdgf1, Sox-2, Nanog, hTERT, Rex1), protein markers (SSEA-3, SSEA-4, TRA-1-81, TRA-1-60, Oct-4) and the ability to differentiate into cells representative of ectoderm, endoderm and mesoderm. In summary, we have established a xeno-free autogenic feeder free system to support undifferentiated expansion of hESc, which could be of clinical relevance.
Acacia honey (AH) has been proven to improve skin wound healing, but its therapeutic effects on corneal epithelium has not been elucidated to date. This study aimed to investigate the effects of AH on cultured corneal epithelial cells (CEC) on in vitro corneal abrasion wound healing model. Six New Zealand white rabbits' CEC were isolated and cultured until passage 1. Circular wound area was created onto a confluent monolayer CEC using a corneal trephine which mimicked corneal abrasion and treated with 0.025% AH supplemented in basal medium (BM) and complete cornea medium (CCM). Wound healing was measured as the percentage of wound closure by the migration of CEC on day 0, day 3 and day 6, post wound creation. The morphological changes of CEC were assessed via phase contrast microscopy. Gene and protein expressions of cytokeratin (CK3), fibronectin and cluster of differentiation 44 (CD44) in AH treated groups and control groups were determined by real-time PCR and immunocytochemistry, respectively.
The role for mechanical stimulation in the control of cell fate has been previously proposed, suggesting that there may be a role of mechanical conditioning in directing mesenchymal stromal cells (MSCs) towards specific lineage for tissue engineering applications. Although previous studies have reported that calcium signalling is involved in regulating many cellular processes in many cell types, its role in managing cellular responses to tensile loading (mechanotransduction) of MSCs has not been fully elucidated. In order to establish this, we disrupted calcium signalling by blocking stretch-activated calcium channel (SACC) in human MSCs (hMSCs) in vitro. Passaged-2 hMSCs were exposed to cyclic tensile loading (1 Hz + 8% for 6, 24, 48, and 72 hours) in the presence of the SACC blocker, gadolinium. Analyses include image observations of immunochemistry and immunofluorescence staining from extracellular matrix (ECM) production, and measuring related tenogenic and apoptosis gene marker expression. Uniaxial tensile loading increased the expression of tenogenic markers and ECM production. However, exposure to strain in the presence of 20 μM gadolinium reduced the induction of almost all tenogenic markers and ECM staining, suggesting that SACC acts as a mechanosensor in strain-induced hMSC tenogenic differentiation process. Although cell death was observed in prolonged stretching, it did not appear to be apoptosis mediated. In conclusion, the knowledge gained in this study by elucidating the role of calcium in MSC mechanotransduction processes, and that in prolonged stretching results in non-apoptosis mediated cell death may be potential useful for regenerative medicine applications.
Anti-Vascular Endothelial Growth Factors (Anti-VEGF) agents have received recent interest as potential anti-fibrotic agents for their concurrent use with trabeculectomy. Preliminary cohort studies have revealed improved bleb morphology following trabeculectomy augmented with ranibizumab. The effects of this humanized monoclonal antibody on human Tenon's fibroblast (HTF), the key player of post trabeculectomy scar formation, are not fully understood. This study was conducted to understand the effects of ranibizumab on extracellular matrix production by HTF. The effect of ranibizumab on HTF proliferation and cell viability was determined using MTT assay (3-(4,5-dimethylthiazone-2-yl)-2,5-diphenyl tetrazolium). Ranibizumab at concentrations ranging from 0.01 to 0.5 mg/mL were administered for 24, 48 and 72 h in serum and serum free conditions. Supernatants and cell lysates from samples were assessed for collagen type 1 alpha 1 and fibronectin mRNA and protein level using quantitative real time polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA). After 48-h, ranibizumab at 0.5 mg/mL, significantly induced cell death under serum-free culture conditions (p
Scaffolds with structural features similar to the extracellular matrix stimulate rapid osteogenic differentiation in favorable microenvironment and with growth factor supplementation. In this study, the osteogenic potential of electrospun poly-l-lactide/hydroxyapatite/collagen (PLLA/Col/HA, PLLA/HA and PLLA/Col) scaffolds were tested in vitro with the supplementation of platelet derived growth factor-BB (PDGF-BB). Cell attachment and topography, mineralization, extracellular matrix protein localization, and gene expression of the human mesenchymal stromal cells were compared between the fibrous scaffolds PLLA/Col/HA, PLLA/Col, and PLLA/HA. The levels of osteocalcin, calcium, and mineralization were significantly greater in the PLLA/Col/HA and PLLA/HA compared with PLLA/Col. High expression of fibronectin, intracellular adhesion molecule, cadherin, and collagen 1 (Col1) suggests that PLLA/Col/HA and PLLA/HA scaffolds had superior osteoinductivity than PLLA/Col. Additionally, osteopontin, osteocalcin, osterix, Runt-related transcription factor 2 (Runx2), and bone morphogenic protein (BMP2) expression were higher in PLLA/Col/HA and PLLA/HA compared with PLLA/Col. In comparison with PLLA/Col, the PLLA/Col/HA and PLLA/HA scaffolds presented a significant upregulation of the genes Runx2, Col 1, Integrin, osteonectin (ON), bone gamma-carboxyglutamic acid-containing protein (BGALP), osteopontin (OPN), and BMP2. The upregulation of these genes was further increased with PDGF-BB supplementation. These results show that PDGF-BB acts synergistically with PLLA/Col/HA and PLLA/HA to enhance the osteogenic differentiation potential. Therefore, this combination can be used for the rapid expansion of bone marrow stromal cells into bone-forming cells for tissue engineering.