Transforming growth factor-beta 1 or ascorbic acid are able to differentiate Wharton's jelly mesenchymal stem cells towards a smooth muscle phenotype.

Wharton's jelly mesenchymal stem cells (WJ-MSCs) are widely used in tissue engineering. In vascular engineering, the ability to obtain a vessel replacement with contractile smooth muscle cells (SMC) is a key factor. In this work, we demonstrated that WJ-MSCs differentiate towards a SMC phenotype with various stimulations in vitro and that the modification of redox state could be involved. WJ-MSCs were isolated from umbilical cords. After their expansion, the cells were stimulated with ascorbic acid (AA, 300 µM) or transforming growth factor (TGF)-ß1 (1 to 5 ng/mL). SMC markers were analyzed by Western blot. Modification of redox state was evaluated by reactive oxygen species (ROS) production and glutathione (GSH) content measurements. TGF-ß1 or AA-stimulated WJ-MSCs express early and intermediate SMC markers. TGF-ß1 (5 ng/mL) modifies the redox state by a ROS production and a GSH content drop, while AA has no effect. This work showed that TGF-ß1 and AA are effective SMC phenotype inducers to differentiate WJ-MSCs.

Quantification of chitinase and thaumatin-like proteins in grape juices and wines.

Chitinases and thaumatin-like proteins are important grape proteins as they have a great influence on wine quality. The quantification of these proteins in grape juices and wines, along with their purification, is therefore crucial to study their intrinsic characteristics and the exact role they play in wines. The main isoforms of these two proteins from Chardonnay grape juice were thus purified by liquid chromatography. Two fast protein liquid chromatography (FLPC) steps allowed the fractionation and purification of the juice proteins, using cation exchange and hydrophobic interaction media. A further high-performance liquid chromatography (HPLC) step was used to achieve higher purity levels. Fraction assessment was achieved by mass spectrometry. Fraction purity was determined by HPLC to detect the presence of protein contaminants, and by nuclear magnetic resonance (NMR) spectroscopy to detect the presence of organic contaminants. Once pure fractions of lyophilized chitinase and thaumatin-like protein were obtained, ultra-HPLC (UHPLC) and enzyme-linked immunosorbent assay (ELISA) calibration curves were constructed. The quantification of these proteins in different grape juice and wine samples was thus achieved for the first time with both techniques through comparison with the purified protein calibration curve. UHPLC and ELISA showed very consistent results (less than 16% deviation for both proteins) and either could be considered to provide an accurate and reliable quantification of proteins in the oenology field.

Review of preparative and analytical procedures for the study of proteins in grape juice and wine.

Proteins have a great influence on wine quality as they exhibit a various range of properties. In fact, they are involved among others in white wine turbidity, organoleptic characteristics and foam formation in sparkling wines. These compounds could also be of major interest for varietal differentiation, regarding wine authentication and traceability issues. To provide a better understanding of the role played by these biomolecules in wine processing and explore their potential applications, there is a manifest need for the quantification and characterization of each individual one in terms of sequence, structure and intrinsic and functional properties. We thus present an overview of preparative and analytical methods for the study of proteins in grape juices and wines, from routine techniques to dedicated methodologies. They include sample preparation with chromatographic methods for the purification and identification of proteins, quantification protocols and characterization procedures such as electrophoretic techniques, immunological methods, sequencing, mass spectrometry, physico-chemical and structural analyses, and so on. We expose advantages and limits of each technique and focus on the different but complementary information they can provide. Despite the past years advances in the field proteins identification, the elucidation of the full protein profile for grape juices and wines remains strenuous. Their interactions with other wine compounds make the challenge even harder. We therefore emphasize the requirement of the techniques to be refined and suggest the developments to be expected.