The proteome of extracellular vesicles released by clastic cells differs based on their substrate

Area of Science:

• Cell Biology
• Proteomics
• Biochemistry

Background:

• Extracellular vesicles (EVs) are crucial for intercellular communication.
• Osteoclasts and odontoclasts are specialized clastic cells involved in bone and dentin resorption, respectively.
• The composition of EVs may vary depending on the cellular origin and environment.

Purpose of the Study:

• To investigate and compare the proteomes of EVs derived from clastic cells cultured on different substrates (plastic, bone, dentin).
• To identify differences in EV protein composition attributable to distinct mineralized matrices.
• To characterize novel protein complexes within these EVs.

Main Methods:

• Proteomic analysis of EVs using two-dimensional high-performance liquid chromatography-mass spectrometry.
• Quantification and statistical analysis of protein abundance (Z-score) to identify differentially expressed proteins.
• Immunoprecipitation to confirm the presence of protein complexes.

Main Results:

• A total of 1,952 proteins were identified across all EV samples.
• EVs from osteoclasts and odontoclasts showed high proteomic similarity (83.3% identity).
• Specific proteins like Stabilin-1 and macrophage mannose receptor-1 were significantly enriched in odontoclast EVs.
• EVs were enriched in subunits of various protein complexes, including proteasome, COP1, COP9, T complex, and a novel vacuolar H+-ATPase (V-ATPase) sub-complex containing the (pro)renin receptor.

Conclusions:

• The protein composition of EVs released by clastic cells is substrate-dependent.
• Odontoclast EVs exhibit unique protein enrichment compared to osteoclast and plastic-cultured EVs.
• Clastic EVs contain assembled protein complexes, including a previously undescribed V-ATPase sub-complex, highlighting their complex cargo.