Engineered parasite could deliver therapeutic proteins

The blood–brain barrier, a selective, semipermeable border around the central nervous system, is the body’s built-in mechanism to protect these critical areas from unwanted intruders like toxins and parasites. But it can also keep out important molecules, like therapeutic proteins, that target this part of the body. In a recent study, scientists demonstrated a mechanism that piggybacks on a single-cell parasite, Toxoplasma gondii , which naturally crosses the blood–brain barrier. Using engineered versions of this parasite, they were able to deliver a protein that’s used to treat a neurological disorder called Rett syndrome directly to nerve cells in the brains of mice ( Nat. Microbiol. 2024, DOI: 10.1038/s41564-024-01750-6 ) . T. gondii is capable of infecting most warm-blooded animals, including humans, and is ubiquitous across the world. It usually enters animals by ingestion, and the parasite then migrates naturally to the central nervous system. It is responsible for causing toxoplasmosis,