Cell type dependent morphological adaptation in polyelectrolyte hydrogels governs chondrogenic fate

Cytochalasins as Modulators of Stem Cell Differentiation

Regenerative medicine aims to identify new research strategies for the repair and restoration of tissues damaged by pathological or accidental events. Mesenchymal stem cells (MSCs) play a key role in regenerative medicine approaches due to their specific properties, such as the high rate of proliferation, the ability to differentiate into several cell lineages, the immunomodulatory potential, and their easy isolation with minimal ethical issues. One of the main goals of regenerative medicine is to modulate, both in vitro and in vivo, the differentiation potential of MSCs to improve their use in the repair of damaged tissues. Over the years, much evidence has been collected about the ability of cytochalasins, a large family of 60 metabolites isolated mainly from fungi, to modulate multiple properties of stem cells (SCs), such as proliferation, migration, and differentiation, by altering the organization of the cyto- and the nucleo-skeleton. In this review, we discussed the ability of two different cytochalasins, cytochalasins D and B, to influence specific SC differentiation programs modulated by several agents (chemical or physical) or intra- and extra-cellular factors, with particular attention to human MSCs (hMSCs).

Engineering Hydrogels for Modulation of Material-Cell Interactions

Hydrogels are a recurrent platform for Tissue Engineering (TE) strategies. Their versatility and the variety of available methods for tuning their properties highly contribute to hydrogels' success. As a result, the design of advanced hydrogels has been thoroughly studied, in the quest for better solutions not only for drugs- and cell-based therapies but also for more fundamental studies. The wide variety of sources, crosslinking strategies, and functionalization methods, and mostly the resemblance of hydrogels to the natural extracellular matrix, make this 3D hydrated structures an excellent tool for TE approaches. The state-of-the-art information regarding hydrogel design, processing methods, and the influence of different hydrogel formulations on the final cell-biomaterial interactions are overviewed herein. This article is protected by copyright. All rights reserved.

Promotion of chondrogenic differentiation of mesenchymal stem cells by copper: Implications for new cartilage repair biomaterials

Copper (Cu) has drawn considerable attention in the design of biomaterials due to its multifunction, such as antibacterial property, osteogenic and angiogenic ability. However, the effect of Cu on chondrogenic differentiation of mesenchymal stem cells (MSCs) and its potential for cartilage repair biomaterials has been rarely studied. Here, we report that Cu can significantly enhance chondrogensis of MSCs. Specifically, in vitro studies showed that Cu could promote MSCs cytoskeleton change, extracellular glycosaminoglycan (GAG) deposition and the chrodrogenic genes (Sox9, Aggrecan, and Col-2) up-regulation. Furthermore, we prepared a Cu-containing alginate (Alg) porous scaffold to assess the chondroinductivity of Cu in vivo. In eight weeks, we found that Alg/Cu scaffolds could induce better formation of new cartilage tissue compared to the pure Alg scaffolds fabricated by the same procedure but without adding Cu. These encouraging results indicate that Cu can bring considerable benefits to the development and application of cartilage repair biomaterials.

Regulation of Scaffold Cell Adhesion Using Artificial Membrane Binding Proteins

The rapid pace of development in biotechnology has placed great importance on controlling cell-material interactions. In practice, this involves attempting to decouple the contributions from adhesion molecules, cell membrane receptors, and scaffold surface chemistry and morphology, which is extremely challenging. Accordingly, a strategy is presented in which different chemical, biochemical, and morphological properties of 3D biomaterials are systematically varied to produce novel scaffolds with tuneable cell affinities. Specifically, cationized and surfactant-conjugated proteins, recently shown to have non-native membrane affinity, are covalently attached to 3D scaffolds of collagen or carboxymethyl-dextran, yielding surface-functionalized 3D architectures with predictable cell immobilization profiles. The artificial membrane-binding proteins enhance cellular adhesion of human mesenchymal stem cells (hMSCs) via electrostatic and hydrophobic binding mechanisms. Furthermore, functionalizing the 3D scaffolds with cationized or surfactant-conjugated myoglobin prevents a slowdown in proliferation of seeded hMSCs cultured for seven days under hypoxic conditions.