Extended preconditioning on soft matrices directs human mesenchymal stem cell fate via YAP transcriptional activity and chromatin organization

Cell origin and microenvironment: The players of differentiation capacity in human mesenchymal stem cells

Mesenchymal stem cells (MSCs) have several important properties that make them desirable for regenerative medicine. These properties include immunomodulatory ability, growth factor production, and differentiation into various cell types. Despite extensive research and promising results in clinical trials, our understanding of MSC biology, their mechanism of action, and their targeted and routine use in clinics is limited. Differentiation of human MSCs (hMSCs) is a complex process influenced by various elements such as growth factors, pharmaceutical compounds, microRNAs, 3D scaffolds, and mechanical and electrical stimulation. Research has shown that different culture conditions can affect the differentiation potential of hMSCs obtained from multiple fetal and adult sources. Additionally, it seems that what affects the differentiation capacities of these cells is their secretory characteristics, which are influenced by the origin of the cells and the local microenvironment where the cells are located. The review can provide insights into the microenvironment-based mechanisms involved in MSC differentiation, which can be valuable for future therapeutic applications.

Multifunctional Adhesive Hydrogels: From Design to Biomedical Applications

Adhesive hydrogels characterized by structural properties similar to the extracellular matrix, excellent biocompatibility, controlled degradation, and tunable mechanical properties have demonstrated significant potential in biomedical applications, including tissue engineering, biosensors, and drug delivery systems. These hydrogels exhibit remarkable adhesion to target substrates and can be rationally engineered to meet specific requirements. In recent decades, adhesive hydrogels have experienced significant advancements driven by the introduction of numerous multifunctional design strategies. This review initially summarizes the chemical bond-based design strategies for tissue adhesion, encompassing static covalent bonds, dynamic covalent bonds, and non-covalent interactions. Subsequently, the multiple functionalities imparted by these diverse design strategies, including highly stretchable and tough performances, responsiveness to microenvironments, anti-freezing/heating properties, conductivity, antibacterial activity, and hemostatic properties are discussed. In addition, recent advances in the biomedical applications of adhesive hydrogels, focusing on tissue repair, drug delivery, medical devices, and wearable sensors are reviewed. Finally, the current challenges are highlighted and future trends in this rapidly evolving field are discussed.

Inflammation alters the expression and activity of the mechanosensitive ion channels in periodontal ligament cells

BACKGROUND

Periodontal ligament cells (PDLCs) possess mechanotransduction capability, vital in orthodontic tooth movement (OTM) and maintaining periodontal homeostasis. The study aims to elucidate the expression profiles of mechanosensitive ion channel (MIC) families in PDLCs and how the inflammatory mediator alters their expression and function, advancing the understanding of the biological process of OTM.

METHODS AND METHODS

Human PDLCs were cultured and exposed to TNF-α. RNA sequencing was conducted to explore the mRNA transcriptome of both normal and TNF-α-treated PDLCs. Differentially expressed MICs were identified and analyzed. The functional expressions of TRPA1 and TRPM8 were further validated by RT-qPCR, Western blot, and calcium influx assays.

RESULTS

All 10 identified MIC families or subfamilies were expressed in PDLCs, with the TRP family being the most abundant. KCNK2, PIEZO1, TMEM87A, and PKD2 were the most expressed ion channels in PDLCs. TNF-α altered the expression of the MIC families, resulting in increased expression of PIEZO, K2P, TRP, TMEM63, and TMEM87 families and decreased expression of ENaC/ASIC, TMC/TMHS/TMIE, TMEM150, TMEM120, and L/T/N-Type calcium channel families. Furthermore, 17 DEMICs were identified (false discovery rate < 0.05), with the top five (fold change ≥ 2), including upregulated TRPA1 and TRPM8. The functional expressions of TRPA1 and TRPM8 were verified, suggesting that TNF-α significantly increased their expression and sensitized their activities.

CONCLUSIONS

The study provides comprehensive expression profiles of the MICs in PDLCs and reveals how inflammation alters the expression and activities of the MICs. Treatments targeting these MICs may offer promising strategies for improving OTM and preventing complications in inflammatory environments, ultimately leading to more effective and safer orthodontic practices.

A well plate-based GelMA photo-crosslinking system with tunable hydrogel mechanical properties to regulate the PTH-mediated osteogenic fate

Versatile and efficient regulation of the mechanical properties of the extracellular matrix is crucial not only for understanding the dynamic changes in biological systems, but also for obtaining precise and effective cellular responses in drug testing. In this study, we developed a well plate-based hydrogel photo-crosslinking system to effectively control the mechanical properties of hydrogels and perform high-throughput assays. We improved cell biocompatibility by using gelatin methacryloyl (GelMA) with a visible light photo-crosslinking method. Multiple cell-laden GelMA hydrogels were simultaneously and uniformly created using multi-arrayed 520 nm light-emitting diodes in a well plate format. The elastic modulus of the hydrogels can be widely adjusted (0.5-30 kPa) using a photo-crosslinking system capable of independently controlling the light intensity or exposure time for multiple samples. We demonstrate the feasibility of our system by observing enhanced bone differentiation of human mesenchymal stem cells (hMSCs) cultured on stiffer hydrogels. Additionally, we observed that the osteogenic fate of hMSCs, affected by the different mechanical properties of the gel, was regulated by parathyroid hormone (PTH). Notably, in response to PTH, hMSCs in a high-stiffness microenvironment upregulate osteogenic differentiation while exhibiting increased proliferation in a low-stiffness microenvironment. Overall, the developed system enables the generation of multiple cell-laden three-dimensional cell culture models with diverse mechanical properties and holds significant potential for expansion into drug testing.