Nanofibrous structures have long been used as scaffolds for tissue engineering (TE) applications, due to their favorable characteristics, such as high porosity, flexibility, high cell attachment and enhanced proliferation, and overall resemblance to native extracellular matrix (ECM). Such scaffolds can be easily produced at a low cost via electrospinning (ESP), but generally cannot be fabricated with a regular and/or complex geometry, characterized by macropores and uniform thickness. We present here a novel technique for direct writing (DW) with solution ESP to produce complex three-dimensional (3D) multiscale and ultrathin (∼1 μm) fibrous scaffolds with desirable patterns and geometries. This technique was simply achieved via manipulating technological conditions, such as spinning solution, ambient conditions, and processing parameters. Three different regimes in fiber morphologies were observed, including bundle with dispersed fibers, bundle with a core of aligned fibers, and single fibers. The transition between these regimes depended on tip to collector distance (Wd) and applied voltage (V), which could be simplified as the ratio V/Wd. Using this technique, a scaffold mimicking the zonal organization of articular cartilage was further fabricated as a proof of concept, demonstrating the ability to better mimic native tissue organization. The DW scaffolds directed tissue organization and fibril matrix orientation in a zone-dependent way. Comparative expression of chondrogenic markers revealed a substantial upregulation of Sox9 and aggrecan (ACAN) on these structures compared to conventional electrospun meshes. Our novel method provides a simple way to produce customized 3D ultrathin fibrous scaffolds, with great potential for TE applications, in particular those for which anisotropy is of importance.

Background: Exosomes secreted from stem cells exerted salutary effects on the fibrotic liver. Herein, the roles of exosomes derived from human embryonic stem cell (hESC) in anti-fibrosis were extensively investigated. Compared with two-dimensional (2D) culture, the clinical and biological relevance of three-dimensional (3D) cell spheroids were greater because of their higher regeneration potential since they behave more like cells in vivo. In our study, exosomes derived from 3D human embryonic stem cells (hESC) spheroids and the monolayer (2D) hESCs were collected and compared the therapeutic potential for fibrotic liver in vitro and in vivo. Results: In vitro, PKH26 labeled-hESC-Exosomes were shown to be internalized and integrated into TGFβ-activated-LX2 cells, and reduced the expression of profibrogenic markers, thereby regulating cellular phenotypes. TPEF imaging indicated that PKH26-labeled-3D-hESC-Exsomes possessed an enhanced capacity to accumulate in the livers and exhibited more dramatic therapeutic potential in the injured livers of fibrosis mouse model. 3D-hESC-Exosomes decreased profibrogenic markers and liver injury markers, and improved the level of liver functioning proteins, eventually restoring liver function of fibrosis mice. miRNA array revealed a significant enrichment of miR-6766-3p in 3D-hESC-Exosomes, moreover, bioinformatics and dual luciferase reporter assay identified and confirmed the TGFβRII gene as the target of miR-6766-3p. Furthermore, the delivery of miR-6766-3p into activated-LX2 cells decreased cell proliferation, chemotaxis and profibrotic effects, and further investigation demonstrated that the expression of target gene TGFβRII and its downstream SMADs proteins, especially phosphorylated protein p-SMAD2/3 was also notably down-regulated by miR-6766-3p. These findings unveiled that miR-6766-3p in 3D-hESC-Exosomes inactivated SMADs signaling by inhibiting TGFβRII expression, consequently attenuating stellate cell activation and suppressing liver fibrosis. Conclusions: Our results showed that miR-6766-3p in the 3D-hESC-Exosomes inactivates smads signaling by restraining TGFβRII expression, attenuated LX2 cell activation and suppressed liver fibrosis, suggesting that 3D-hESC-Exosome enriched-miR-6766-3p is a novel anti-fibrotic therapeutics for treating chronic liver disease. These results also proposed a significant strategy that 3D-Exo could be used as natural nanoparticles to rescue liver injury via delivering antifibrotic miR-6766-3p. Graphical

Integrin β1 (ITGB1), which acts as an extracellular matrix (ECM) receptor, has gained increasing attention as a therapeutic target for the treatment of hepatocellular carcinoma (HCC). However, the underpinning mechanism of how ITGB1 drives HCC progression remains elusive. In this study, we first found that ITGB1 expression was significantly higher in HCC tissues than in normal controls by bioinformatics analysis. Furthermore, bioinformatics analysis revealed that paxillin (PXN) and 14-3-3 protein zeta (YWHAZ) are the molecules participating in ITGB1-regulated HCC tumor cell cycle progression. Indeed, immunohistochemistry (IHC) revealed that ITGB1, paxillin, and YWHAZ were strongly upregulated in paired HCC tissue compared with adjacent normal tissues. Notably, the inhibition of ITGB1 expression by small interfering RNA (siRNA) resulted in the downregulated expression of PXN and YWHAZ in primary HCC cells, as assessed by western blot and immunostaining. In addition, ITGB1 knockdown markedly impaired the aggressive behavior of HCC tumor cells and delayed cell cycle progression as determined by cell migration assay, drug-resistance analysis, colony formation assay, quantitative real-time polymerase chain reaction (qRT-PCR), and cell cycle analysis as well as cell viability measurements. More importantly, we proved that xenograft ITGB1^high tumors grew more rapidly than ITGB1^low tumors. Altogether, our study showed that the ITGB1/PXN/YWHAZ/protein kinase B (AKT) axis enhances HCC progression by accelerating the cell cycle process, which offers a promising approach to halt HCC tumor growth.

Objectives: For clinical applications of cell‐based therapies, a large quantity of human pluripotent stem cells (hPSCs) produced in standardized and scalable culture processes is required. Currently, microcarrier‐free suspension culture shows potential for large‐scale expansion of hPSCs; however, hPSCs tend to aggregate during culturing leading to a negative effect on cell yield. To overcome this problem, we developed a novel protocol to effectively control the sizes of cell aggregates and enhance the cell proliferation during the expansion of hPSCs in suspension.Materials and Methods: hPSCs were expanded in suspension culture supplemented with polyvinyl alcohol (PVA) and dextran sulphate (DS), and 3D suspension culture of hPSCs formed cell aggregates under static or dynamic conditions. The sizes of cell aggregates and the cell proliferation as well as the pluripotency of hPSCs after expansion were assessed using cell counting, size analysis, real‐time quantitative polymerase chain reaction, flow cytometry analysis, immunofluorescence staining, embryoid body formation, teratoma formation and transcriptome sequencing.Results: Our results demonstrated that the addition of DS alone effectively prevented hPSC aggregation, while the addition of PVA significantly enhanced hPSC proliferation. The combination of PVA and DS not only promoted cell proliferation of hPSCs but also produced uniform and size‐controlled cell aggregates. Moreover, hPSCs treated with PVA, or DS or a combination, maintained the pluripotency and were capable of differentiating into all three germ layers. mRNA‐seq analysis demonstrated that the combination of PVA and DS significantly promoted hPSC proliferation and prevented cell aggregation through improving energy metabolism‐related processes, regulating cell growth, cell proliferation and cell division, as well as reducing the adhesion among hPSC aggregates by affecting expression of genes related to cell adhesion.Conclusions: Our results represent a significant step towards developing a simple and robust approach for the expansion of hPSCs in large scale.