Transduction of beta3 integrin subunit cDNA confers on human keratinocytes the ability to adhere to gelatin

The Psoriasis Therapeutic Potential of a Novel Short Laminin Peptide C16

Psoriasis is a chronic inflammatory skin disease characterized by excessive growth of keratinocytes and hyperkeratosis in the epidermis. An abnormality of the non-lesional epidermis at an early stage of psoriasis is involved in triggering inflammatory cell infiltration into the dermis. Integrin α5β1 acts as a receptor for fibronectin and has been found to be overexpressed in non-lesional psoriatic epidermis. To investigate whether α5β1 integrin has a potential as a drug target for psoriasis treatment, the α5β1 integrin-binding peptide, C16, was used to obstruct the HaCat keratinocyte cellular responses induced by fibronectin (Fn) in culture and psoriasis-like skin inflammation induced in mice by imiquimod (IMQ). The C16 exhibited antagonistic activity against α5β1 integrin in HaCat cells, with evidence of suppression of the Fn-mediated proliferative, cytoskeletal, and inflammatory responses. Topical treatment with C16 greatly reduced the IMQ-induced epidermal hyperplasia, infiltration of neutrophils/macrophages, and expression of pro-inflammatory mediators in mouse skin. The C16SP (C16-derived short peptide; DITYVRLKF) also exhibited antagonistic activity, suppressing α5β1 integrin activity in culture, and reducing IMQ-induced skin inflammation. Taken together, this study provides the first evidence that α5β1 integrin may be a potential drug target for psoriasis. The synthetic C16 peptide may serve as an agent for psoriasis therapy.

Formulation Changes Affect Material Properties and Cell Behavior in HA-Based Hydrogels

To develop and optimize new scaffold materials for tissue engineering applications, it is important to understand how changes to the scaffold affect the cells that will interact with that scaffold. In this study, we used a hyaluronic acid- (HA-) based hydrogel as a synthetic extracellular matrix, containing modified HA (CMHA-S), modified gelatin (Gtn-S), and a crosslinker (PEGda). By varying the concentrations of these components, we were able to change the gelation time, enzymatic degradation, and compressive modulus of the hydrogel. These changes also affected fibroblast spreading within the hydrogels and differentially affected the proliferation and metabolic activity of fibroblasts and mesenchymal stem cells (MSCs). In particular, PEGda concentration had the greatest influence on gelation time, compressive modulus, and cell spreading. MSCs appeared to require a longer period of adjustment to the new microenvironment of the hydrogels than fibroblasts. Fibroblasts were able to proliferate in all formulations over the course of two weeks, but MSCs did not. Metabolic activity changed for each cell type during the two weeks depending on the formulation. These results highlight the importance of determining the effect of matrix composition changes on a particular cell type of interest in order to optimize the formulation for a given application.