Cationic Peptoids for Systemic In Vivo Cartilage-Targeting

Area of Science:

• Biomaterials Science
• Molecular Imaging
• Drug Delivery

Background:

• Cartilage damage is central to osteoarthritis and rheumatoid arthritis (RA).
• Cartilage's avascular nature and dense matrix impede imaging and drug delivery.
• Existing cartilage-targeting peptides often lack serum stability.

Purpose of the Study:

• To develop novel cartilage-targeting agents with enhanced stability and penetration.
• To investigate the potential of cationic peptidomimetics for molecular imaging and drug delivery in cartilage.
• To assess the in vivo performance and biocompatibility of these new compounds.

Main Methods:

• Synthesis of Nlys-rich peptidomimetics (N-substituted butyl-amino glycine).
• In vitro studies using cartilage plugs to evaluate penetration and binding to glycosaminoglycan (GAG) chains.
• In vivo studies in mice and zebrafish using Cy5-labeled compounds for imaging and assessing GAG loss.
• Cytotoxicity and biocompatibility assessments in chondrocytes and in vivo.

Main Results:

• Nlys-rich sequences effectively penetrate and bind to GAGs in deep cartilage plugs.
• The peptidomimetics exhibit high serum stability, overcoming limitations of current peptides.
• Intravenous administration allows whole-body cartilage uptake and imaging in vivo.
• Demonstrated in vivo detection of GAG loss in aged and inflamed joints.
• No observed cytotoxicity in chondrocytes and good in vivo biocompatibility.

Conclusions:

• Nlys-peptidomimetics represent a novel class of agents for targeting cartilage GAGs.
• These compounds offer improved stability and penetration for enhanced cartilage imaging and drug delivery.
• The findings support potential applications in diagnosing and treating cartilage-related diseases.