Intervertebral Disc Proteoglycans: Multifunctional Tissue Stabilizing and Instructional Cell Regulatory Proteins That...

Area of Science:

• Biochemistry and Molecular Biology
• Biomaterials Science
• Spinal Anatomy and Physiology

Background:

• The intervertebral disc (IVD) is a complex fibrocartilaginous structure essential for spinal biomechanics.
• Its mechanical properties rely on a composite matrix, including collagens, proteoglycans (PGs), and elastin.
• Proteoglycans are vital for weight-bearing, tissue organization, and cellular signaling within the IVD.

Purpose of the Study:

• To review the diverse structures and functions of intervertebral disc proteoglycans (IVD PGs).
• To highlight the roles of specific PGs like perlecan, bikunin, and lubricin in IVD tissue regulation.
• To explore the potential of bioactive PG fragments in regenerative medicine for IVD repair.

Main Methods:

• Literature review synthesizing existing research on IVD PGs.
• Analysis of the structural and functional properties of identified IVD PGs.
• Discussion of emerging roles and potential applications of PG fragments.

Main Results:

• A total of 19 IVD PGs have been identified, with perlecan, bikunin, and lubricin showing significant functional relevance.
• Perlecan contributes to tissue stabilization, cell regulation, and mechanosensing; bikunin offers tissue protection; lubricin may provide lubrication and modulate inflammation.
• Fragmentation of IVD PGs during tissue turnover generates bioactive fragments with potential for therapeutic applications in IVD repair.

Conclusions:

• IVD PGs play multifaceted roles in maintaining disc homeostasis, cellular function, and tissue integrity.
• Specific PGs like perlecan, bikunin, and lubricin are critical regulators of IVD physiology.
• Further investigation into bioactive PG fragments holds promise for developing novel strategies for IVD regeneration.