Yeast as a model system for identification of metabolic targets of a 'glucosamine complex' used as a therapeutic agent of osteoarthritis.

This manuscript describes the effect of a glucosamine complex and its different constituents on the metabolism of yeast cells. Indeed, the yeast model biosystem offers important advantages in the understanding of basic cellular and molecular processes. For example, the possibility to differentiate aerobic and anaerobic metabolism allows the measurement of glycolysis and mitochondria importance in the control of energetic metabolism and stress-responsive. Yeast growth and division can be controlled efficiently and effectively by adjusting environmental conditions that mimic some aspect of those experienced by chondrocytes in an osteoarthritic milieu, such as low oxygen and nutriment availabilities, high oxidative stress, etc. The glucosamine complex or some of its components (glucosamine sulphate, MSM, Ribes nigrum and silicon) enhanced cellular proliferation and CO(2) production of yeast cells cultured under severe conditions. In addition, it allows a larger output of protons from the cells into the medium. Glucosamine complex supplementation also boosted cellular resistance to stresses such as heat shock, H(2)O(2)-induced peroxidation and ethanol. The beneficial effects of the complex were primarily due to R. nigrum and to glucosamine sulphate components. The protective effect of the glucosamine complex can be explained by an increase of cellular energy level through intensification of mitochondrial functionality and intracellular machinery (anaerobic glycolysis). An additional effect on protein kinase activation is not unlikely.