The heparan sulfate and its diverse biological activities

Heparan sulfate (HS) is one of the most common glycosaminoglycan (GAG) in mammals. It is composed of relatively simple disaccharide subunits, which, by further modification, such as sulfation and epimerization, potentially offer huge diversity in biological function. GAG chains of different length, different patterns of sulfation, and other modifications, depending on location, generate unique forms. Due to polyanion charges, these compounds can interact with other molecules, such as proteins, cytokines, chemokines and growth factors, both on the cell surface and inside the extracellular matrix. These interactions serve protective and storage functions for the compounds, safeguarding them from proteolysis. In this way, HS is involved in numerous signaling pathways, and in growth and differentiation processes. Disrupted interactions between the HS and growth factors, cytokines or other proteins have been observed in various disorders, among these Alzheimer’s disease, epilepsy, atherosclerosis, diabetes, and cancer processes. Detailed knowledge of these relationships at the molecular level will allow researchers to understand the mechanisms underlying these disorders and enable the development of effective therapeutic strategies.