Mitochondrial cargo export in exosomes: Possible pathways and implication in disease biology

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• Exosome biogenesis is linked to endocytic pathways, influencing cargo loading.
• Autophagy normally degrades cellular components via lysosomes.
• Noncanonical fusion of autophagosomes with multivesicular bodies (MVBs) offers an alternative cargo export route.

Purpose of the Study:

• To review the concept of autophagic routes contributing to exosome biogenesis.
• To discuss the generation of mitochondrial cargo-enriched exosomes (mt-enREXO).
• To explore the role of mt-enREXO in paracrine signaling and diagnostics.

Main Methods:

• Review of existing literature on exosome biogenesis, autophagy, and endosomal pathways.
• Discussion of the noncanonical fusion mechanism between autophagosomes and MVBs.
• Analysis of the role of LC3 protein as an autophagic flux marker in exosomes.

Main Results:

• Autophagy, including mitophagy, can lead to the formation of amphisome-like structures.
• These structures facilitate the loading of autophagic cargo, such as mitochondrial components, into exosomes.
• Mitochondrial cargo-enriched exosomes (mt-enREXO) are generated and can be detected by markers like LC3.

Conclusions:

• Intracellular autophagic routes are involved in the generation of mt-enREXO.
• mt-enREXO are potent regulators of paracrine signaling with implications in both health and disease.
• These vesicles hold potential utility in diagnostic applications.