Chemical and mechanical properties of a tumor microenvironment are essential players in cancer progression, and it is important to precisely control the extracellular conditions while designing cancer in vitro models. The study investigates synthetic hydrogel matrices from multi-arm polyethylene glycol (PEG) functionalized with collagen-like peptide (CLP) CG(PKG) 4 (POG) 4 (DOG) 4 alone and conjugated with either cell adhesion peptide RGD (mimicking fibronectin) or IKVAV (mimicking laminin). Human glioblastoma HROG36, rat C6 glioma cells, and A375 human melanoma cells were grown on the hydrogels and monitored for migration, proliferation, projected cell area, cell shape index, size and number, distribution of focal contacts in individual cells, and focal adhesion number. PEG-CLP-RGD induced migration of both glioma cell lines and also stimulated proliferation (assessed as metabolic activity) of HROG36 cells. Migration of C6 cells were also stimulated by PEG-CLP-IKVAV. These responses strongly correlated with the changes in adhesion and morphology parameters of individual cells-projected cell area, cell shape index, and focal contact number. Melanoma A375 cell proliferation was increased by PEG-CLP-RGD, and this was accompanied by a decrease in cell shape index. However, neither RGD nor IKVAV conjugated to PEG-CLP stimulated migratory capacity of A375 cells. Taken together, the study presents synthetic scaffolds with extracellular matrix (ECM)-mimicking peptides that allow for the exploration of the effect of ECM signaling to cancer cells.

Dilated cardiomyopathy (DCM) is the most common type of nonischemic cardiomyopathy characterized by left ventricular or biventricular dilation and impaired contraction leading to heart failure and even patients’ death. Therefore, it is important to search for new cardiac tissue regenerating tools. Human mesenchymal stem/stromal cells (hmMSCs) were isolated from post-surgery healthy and DCM myocardial biopsies and their differentiation to the cardiomyogenic direction has been investigated in vitro. Dilated hmMSCs were slightly bigger in size, grew slower, but had almost the same levels of MSC-typical surface markers as healthy hmMSCs. Histone deacetylase (HDAC) activity in dilated hmMSCs was 1.5-fold higher than in healthy ones, which was suppressed by class I and II HDAC inhibitor suberoylanilide hydroxamic acid (SAHA) showing activation of cardiomyogenic differentiation-related genes alpha-cardiac actin (ACTC1) and cardiac troponin T (TNNT2). Both types of hmMSCs cultivated on collagen I hydrogels with hyaluronic acid (HA) or 2-methacryloyloxyethyl phosphorylcholine (MPC) and exposed to SAHA significantly downregulated focal adhesion kinase (PTK2) and activated ACTC1 and TNNT2. Longitudinal cultivation of dilated hmMSC also upregulated alpha-cardiac actin. Thus, HDAC inhibitor SAHA, in combination with collagen I-based hydrogels, can tilt the dilated myocardium hmMSC toward cardiomyogenic direction in vitro with further possible therapeutic application in vivo.

One key element to the health of the ocular surface encompasses the presence of gel-forming mucins in the pre-ocular tear film. Conjunctival goblet cells are specialized epithelial cells that secrete mucins necessary for tear film stability and general homeostasis. Their dysfunction can be linked to a range of ocular surface inflammation disorders and chronic injuries. To obtain new perspectives and angles to tackle mucin deficiency, the need for an accurate evaluation of their presence and corresponding mucin secretion in ex vivo conjunctival cultures has become a requisite. In vitro, goblet cells show a significant decrease in the production and secretion of gel-forming mucins, accompanied by signs of dedifferentiation or transdifferentiation. Explant cultures on laminin-treated CLP-PEG hydrogels can, however, support the production of gel-forming mucins. Together, we challenge the current paradigm to evaluate the presence of cultured goblet cells solely based on their general mucin (MUC) content through imaging analyses, showing the need for additional techniques to assess the functionality of goblet cells. In addition, we broadened the gel-forming mucin profile of in vivo goblet cells with MUC5B and MUC6, while MUC2 and MUC6 is added to the profile of cultured goblet cells.

Herein we address, hyaline cartilage regeneration issue by engineering a synthetic biocompatible hydrogel scaffold capable to promote chondrogenic differentiation. In this study, the chemically crosslinked hydrogels consisting of synthetic peptides that have the collagen-like sequence Cys-Gly-(Pro-Lys-Gly)4 (Pro-Hyp-Gly)4 (Asp-Hyp-Gly)4- conjugated with RGD sequence (CLP-RGD) and crosslinked hydrogels of type I collagen (CA) were used. For cartilage formation, we used human skeletal muscle-derived stem/progenitor cells (hMDSPCs) set for differentiation towards a chondrogenic lineage by BMP-7 and TGF-ß3 growth factors.Initially 150, 100 and 75 ng of BMP-7and TGF-ß3 growth factors were inserted in each scaffold and amount of growth factors diffusing out of the scaffolds was observed by ELISA assays. In vitro experiments were performed by seeding hMDSPCs onto hydrogels loaded with growth factors (75ng/scaffold) and cultured for 28 days. Cartilage formation was monitored by ELISA and RT-PCR assays. All experiments were performed in triplicates or quadruplicates.Growth factors incorporation strategy allowed a sustained release of TGF-ß3 growth factor, 6.00.3% of the initially loaded amount diffused out after 4 h and 2.70.5% already at the second time point (24h) from CA and CLP-RGD substrates. For the BMP-7 growth factor, 13.12.3% and 15.751.6% of the initially loaded amount diffused out after 4 h, 1.70.2% and 2.450.3% at the second time point (24 h) from CA and CLP-RGD respectively. In vitro experiments shown that scaffolds with immobilized growth factors resulted in higher collagen type II accumulation when compared to the scaffolds alone. The gene expression on CLP-RGD hydrogels with growth factors has shown lower collagen type I expression and higher aggrecan expression compared to day 0. However, we also report increased collagen X gene expression on CA hydrogels (with growth factors).Our results support the potential of the strategy of combining hydrogels functionalized with differentiation factors toward improving cartilage repair.