Which GAG is primarily important for maintaining the integrity of the extracellular matrix (ECM), especially in the central nervous system (CNS)?

Hyaluronic acid is a key glycosaminoglycan (GAG) that plays a crucial role in maintaining the integrity of the extracellular matrix (ECM), particularly in the central nervous system (CNS). Its unique properties include the ability to retain water and provide turgidity, which supports tissue hydration and tensile strength. Hyaluronic acid is abundant in various tissues, including the synovial fluid of joints and the ECM of the CNS, where it contributes to the formation of the neural ECM and supports neuronal cells.

In the context of the CNS, hyaluronic acid helps facilitate cell signaling and provides a scaffold that supports not only neuronal growth but also repair processes following injury. Its large size and high negative charge enable it to attract water, forming a gel-like substance that can cushion and protect neurons and other cells in the CNS.

Other glycosaminoglycans, while important in various tissues and for specific functions, do not serve the same broad and multifunctional role in the ECM of the CNS as hyaluronic acid does. For example, chondroitin sulfate plays a significant role in cartilage structure and function, while heparan sulfate is important in cell signaling and interactions, particularly within the vascular system. Dermatan sulfate has its