The researchers found that EV-treated macrophages produce compounds like reactive oxygen species that can promote the killing of the M tuberculosis once it infects the macrophage
Structures released by tuberculosis-infected cells may be used in tandem with antibiotics to boost the body’s immune system, helping fight off the disease, according to a study. The study, published in the journal EMBO Reports, found that the structures, called extracellular vesicles (EVs), contain Mycobacterium tuberculosis RNA — a molecule essential in various biological roles — and transfer it to other cells.
This starts a built-in weapon system against the disease in the form of an immune response, said researchers from the University of Notre Dame in the US. Though extracellular vesicles containing RNA from viruses had been discovered years ago, the researchers recently discovered RNA from bacteria — Mycobacterium tuberculosis — in EVs. This discovery led to experiments to determine how the bacteria’s RNA was affecting the “target” cell, including cells infected by M tuberculosis.
A key discovery hinges on macrophages, which are cells of the immune system, researchers said. These cells, when treated with EVs released from M tuberculosis-infected cells, can control the infection better than macrophages not previously exposed to the EVs, they said. “It had never before been shown that bacterial RNA in EVs can activate this sensing pathway, one that has primarily been thought to be involved in viral sensing,” said Jeffrey Schorey, a professor at the University of Notre Dame. The researchers found that EV-treated macrophages produce compounds like reactive oxygen species that can promote the killing of the M tuberculosis once it infects the macrophage.
The discovery is important because it can lead to future therapies for treatment of tuberculosis, researchers said. Preliminary data suggests that antibiotics might work better when combined with an immunotherapy based on using these EVs. The data from the mouse model showed that more of the bacterial-infected cells were killed with the combination of therapies than either antibiotics or EVs alone, Schorey noted.