Unveiling exosomes: Cutting-edge isolation techniques and their therapeutic potential

Abstract

Exosomes are one type of nanosized membrane vesicles with an endocytic origin. They are secreted by almost all cell types and play diverse functional roles. It is essential for research purposes to differentiate exosomes from microvesicles and isolate them from other components in a fluid sample or cell culture medium. Exosomes are important mediators in cell-cell communication. They deliver their cargos, such as mRNA transcripts, microRNA, lipids, cytosolic and membrane proteins and enzymes, to target cells with or without physical connections between cells. They are highly heterogeneous in size, and their biological functions can vary depending on the cell type, their ability to interact with recipient cells and transport their contents, and the environment in which they are produced. This review summarized the recent progress in exosome isolation and characterization techniques. Moreover, we review the therapeutic approaches, biological functions of exosomes in disease progression, tumour metastasis regulation, immune regulation and some ongoing clinical trials.

Keywords: cancer therapy; characterization; exosome; immune modulation; isolation.

FIGURE 1

Schematic overview of common Methods for identifying, characterizing and analysing the functional properties of exosomes.

FIGURE 2

Differential UC. This technique commonly used in the field of biochemistry and molecular biology to separate and isolate different components of a biological sample based on their size, shape and density using high‐speed centrifugation.

FIGURE 3

Sequential filtration. Sequential filtration begins by employing a filter with a relatively larger pore size, enabling the retention of larger particles while permitting smaller particles to pass through. The resulting filtrate from the initial filtration is then subjected to successive filtration stages utilizing filters featuring progressively smaller pore sizes. This iterative sequential filtration can be repeated several times to attain a more precise size‐based separation.

FIGURE 4

Clinical applications of exosomes. Exosomes can be extracted from bodily fluids, lymph, bile, blood, urine and etc. Analysing the molecular contents of exosomes can provide unique opportunities in their identifications. Exosomes can be used as biomarkers in disease diagnosis and surveillance. Clinical treatment mostly involves these strategies: First, cargo, including drugs, nucleic acids and proteins, can be encapsulated in exosomes and targeted to the mentioned sites. Also, immunotherapy can be used in cancer and other disease therapies.