ABSTRACT
BACKGROUND@#Reliable in vitro cellular models are needed to study the phenotypic modulation of smooth muscle cells (SMCs) in health and disease. The aim of this study was to optimize gelatin methacrylate (GelMA)/alginate hydrogels for bioprinting three-dimensional (3D) SMC constructs. @*METHODS@#Four different hydrogel groups were prepared by mixing different concentrations (% w/v) of GelMA and alginate: G1 (5/1.5), G2 (5/3), G3 (7.5/1.5), and G4 (7.5/3). GelMA 10% was used as control (G5). A circular structure containing human bladder SMCs was fabricated by using an extrusion-based bioprinter. The effects of the mixing ratios on printability, viability, proliferation, and differentiation of the cells were investigated. @*RESULTS@#Rheological analysis showed that the addition of alginate significantly stabilized the change in mechanical properties with temperature variations. The group with the highest GelMA and alginate concentrations (G4) exhibited the highest viscosity, resulting in better stability of the 3D construct after crosslinking. Compared to other hydrogel compositions, cells in G4 maintained high viability ([ 80%), exhibited spindle-shaped morphology, and showed a significantly higher proliferation rate within an 8-day period. More importantly, G4 provided an optimal environment for the induction of a SMC contractile phenotype, as evidenced by significant changes in the expression of marker proteins and morphological parameters. @*CONCLUSION@#Adjusting the composition of GelMA/alginate hydrogels is an effective means of controlling the SMC phenotype. These hydrogels support bioprinting of 3D models to study phenotypic smooth muscle adaptation, with the prospect of using the constructs in the study of therapies for the treatment of urethral strictures.
ABSTRACT
Objective To study the effect of S1P on HLF cell fibrosis and its mechanism. Methods (1) The expression of ECM in HLF cells was analyzed by using Western Blot after treatment by S1P(1 μmol/L), FTY720-P(5μmol/L),ponesimod(5μmol/L)and SEW2871(5μmol/L)24 h;(2)The HLF cells were pre-treated using selective S1PR antagonist W146(1 μmol/L),JTE-013(0.2 μmol/L),and TY-52156(1.25 μmol/L)1 h before incubation by S1P and S1PR agonists 24 h and then the expression of ECM was analyzed;(3)The HLF cells were pre-incubated using JTE-013(0.2μmol/L)and TY-52156(1.25μmol/L)for 1 h and then the expression of ECM was analyzedafter being treated by S1P and S1PR agonists 24 h. Results (1)S1P and selective S1P receptor agonist increased the expression of ECM to various extents;(2)The S1P1R antagonist W146 did not affectthe expression of ECM induced by S1P and S1PR agonists and S1P2R antagonist JTE-013 and S1P3R antagonist TY-52156 both decreased the expression of ECM induced by S1P and S1PR agonists;(3)The expression of ECM induced by S1P and S1PR agonists further decreased using both JTE-013 and TY-52156 but not using ponesimod. Conclusion S1P2R and S1P3R are activated under the influence of S1P so as to increase the synthesis of ECM and promote fibrosis gene expression in HLF cells.