Endosomal signalling via exosome surface TGFβ-1.

Area of Science:

• Cell Biology
• Biochemistry
• Immunology

Background:

• Extracellular vesicles, including exosomes, mediate intercellular communication.
• Transforming growth factor β-1 (TGFβ-1) plays critical roles in cell function and differentiation.
• Mast cells and mesenchymal stem cells (MSCs) are involved in tissue repair and immune responses.

Purpose of the Study:

• To investigate the role of mast cell-derived exosomes in delivering TGFβ-1 to recipient cells.
• To determine the mechanism of TGFβ-1 association with exosomes and its fate in recipient cells.
• To assess the functional impact of exosome-mediated TGFβ-1 delivery on MSCs.

Main Methods:

• Isolation and characterization of exosomes from mast cells.
• Analysis of TGFβ-1 association with exosomes using biochemical assays.
• Tracking exosome uptake and intracellular localization in human MSCs via microscopy.
• Assessment of MSC migration and SMAD pathway activation following exosome exposure.

Main Results:

• Mast cell exosomes were found to carry both active and latent TGFβ-1 on their surface.
• Latent TGFβ-1 was associated with exosomes via heparinase-II and pH-sensitive interactions.
• Exosomes were rapidly internalized by MSCs, with TGFβ-1 retained within endosomal compartments.
• Exosome-delivered TGFβ-1 induced prolonged signaling and promoted MSC migration through SMAD-dependent pathways.

Conclusions:

• Mast cell-derived exosomes act as carriers for latent TGFβ-1, delivering it to recipient MSCs.
• The endosomal retention of exosome-associated TGFβ-1 enhances and prolongs cellular signaling.
• Exosomes facilitate intercellular communication by delivering bioactive surface ligands to intracellular compartments, influencing recipient cell behavior.