Stem cells play essential roles in tissue regeneration in vivo via specific lineage differentiation induced by environmental factors. In the past, biochemical signals were the focus of induced stem cell differentiation. As reported by Engler et al (2006 Cell 126 677-89), biophysical signal mediated stem cell differentiation could also serve as an important inducer. With the advancement of material science, it becomes a possible strategy to generate active biophysical signals for directing stem cell fate through specially designed material microstructures. In the past five years, significant progress has been made in this field, and these designed biophysical signals include material elasticity/rigidity, micropatterned structure, extracellular matrix (ECM) coated materials, material transmitted extracellular mechanical force etc. A large number of investigations involved material directed differentiation of mesenchymal stem cells, neural stem/progenitor cells, adipose derived stem cells, hematopoietic stem/progenitor cells, embryonic stem cells and other cells. Hydrogel based materials were commonly used to create varied mechanical properties via modifying the ratio of different components, crosslinking levels, matrix concentration and conjugation with other components. Among them, polyacrylamide (PAM) and polydimethylsiloxane (PDMS) hydrogels remained the major types of material. Specially designed micropatterning was not only able to create a unique topographical surface to control cell shape, alignment, cell-cell and cell-matrix contact for basic stem cell biology study, but also could be integrated with 3D bioprinting to generate micropattered 3D structure and thus to induce stem cell based tissue regeneration. ECM coating on a specific topographical structure was capable of inducing even more specific and potent stem cell differentiation along with soluble factors and mechanical force. The article overviews the progress of the past five years in this particular field.

Background Emerging studies have revealed the potent functions of circRNAs in breast cancer tumorigenesis. However, the biogenesis, biofunction and mechanism of circRNAs in triple-negative breast cancer (TNBC) are largely unknown. Methods High-throughput RNA sequencing was applied to identify dysregulated circRNAs in TNBCs and paired normal tissues. RNA pulldown and luciferase assays were performed to investigate the interaction between circular CD44 (circCD44, also annotated as hsa_circ_0021735) and miR-502–5p. RNA pulldown and RIP assays were used to investigate the interaction between circCD44 and IGF2BP2. Cell viability, colony formation, migration/invasion assays and in vivo tumorigenesis were used to investigate circCD44 biological functions. Results CircCD44 is an uncharacterized circRNA, which is highly expressed in TNBC, and its expression is negatively correlated with the prognosis of TNBC patients. CircCD44 promotes TNBC proliferation, migration, invasion and tumorigenesis at least partially by sponging miR-502–5p and interacting with IGF2BP2. Conclusion Our data suggested that overexpressed circCD44 promotes TNBC progression. CircCD44 is potentially a novel diagnostic and therapeutic marker for TNBC patients.

Synthetic polymers such as polyglycolic acid (PGA) fibers are the traditional tissue engineering scaffolds that are widely used for engineering a variety of soft tissues. However, the major disadvantage of this polymer material is its released acidic degradation products that trigger inflammatory response and fibrotic process, which affects the biocompatibility and the quality of the engineered tissues. In this study, the effect of hyaluronic acid (HA) coating on improving PGA biocompatibility was explored. The results showed that 1% HA solution could better coat PGA fibers than other tested concentrations of HA, and coated PGA exhibited less inflammatory reaction upon in vivo subcutaneous implantation. In vitro characterization demonstrated that HA coating could enhance cell adhesion to the scaffold and reduce gene expression of IL-1, IL-6, IL-8, and α-SMA. It also decreased the acidity of degradation products in vitro. Furthermore, coated PGA could engineer better cartilages in vitro with higher content of total collagen and glycosaminoglycan, as well as higher gene expression levels of collagen II, aggrecan, and Sox9. Collectively, the data indicate that HA coating can significantly enhance the biocompatibility of this traditional scaffold material, which also enhances the quality of engineered tissues.

Introduction: Basic fibroblast growth factor (bFGF) plays several key roles in wound healing. Over the last 2 decades, clinical and basic research on bFGF has been actively conducted in Japan with reports on its potent efficacy in accelerating the healing of chronic ulcers and burn wounds by stimulating key cellular players in the skin. However, its efficacy remains unrecognized internationally. Thus, this study reviews current knowledge about the therapeutic value of bFGF in wound management and scar prevention accumulated in Japan over the last 2 decades. Methods: We review the Japanese literature that demonstrates the anti-scarring effects of bFGF and exhaustively assess how these effects are exerted. Using the search terms ''bFGF OR growth factors AND wound healing in Japan'' and ''bFGF AND scar prevention in Japan,'' we conducted a search of the PubMed database for publications on the role of bFGF in wound and scar management in Japan. All eligible papers published between 1988 and December 2019 were retrieved and reviewed. Results: Our search yielded 208 articles; 82 were related to the application of bFGF for dermal wound healing in Japan. Of these, 27 fulfilled all inclusion criteria; 11 were laboratory studies, 7 were case reports, 4 were clinical studies, and 5 were randomized controlled trials. Conclusion: Further research, with recognition of the therapeutic value of bFGF in wound and scar management and its clinical applications, is needed to provide additional clinical advantages while improving wound healing and reducing the risk of post-surgical scar formation.