Extracellular vesicles as tools and targets in therapy for diseases

Extracellular vesicles (EVs) are membrane-bound particles secreted by nearly all cell types into the extracellular space. Once dismissed as mere cellular waste, they are now recognized as sophisticated mediators of intercellular communication. By transporting complex molecular payloads—including mRNAs, miRNAs, DNA, proteins, and lipids—across the body, they influence physiological homeostasis and contribute to the development of pathological states. Their presence in all major bodily fluids, such as blood, urine, and saliva, makes them a frontier for non-invasive diagnostic monitoring.

EVs are central to the tumor microenvironment (TME). Cancer cells often hijack EV pathways to facilitate metastasis by remodeling the extracellular matrix, promoting angiogenesis, and establishing pre-metastatic niches in distant organs. Beyond structural support, EVs act as agents of immune evasion; for example, tumor-derived EVs carrying PD-L1 can suppress T-cell activity, shielding malignant cells from the host's immune system. In other conditions, such as neurodegenerative diseases, EVs serve as vectors for pathogenic proteins like tau and alpha-synuclein, potentially propagating protein aggregation across neural networks. Similarly, in autoimmune disorders and diabetes, EVs can transport inflammatory signals that exacerbate tissue destruction and metabolic dysfunction.

Because of their natural biocompatibility and capacity to bypass immune rejection, EVs are being engineered as therapeutic tools. Researchers are exploring them as next-generation drug delivery vehicles that can be loaded with chemotherapeutic agents or gene-silencing RNA to treat tumors with high precision. Additionally, EVs derived from stem cells, such as mesenchymal stem cells (MSCs), are under investigation for their ability to promote tissue repair and reduce inflammation. Experimental vaccines utilizing antigen-enriched EVs are also showing promise in activating the immune system against persistent viral infections and various cancers.