The bacterium that causes leprosy spreads through the body by reprogramming infected cells to become stem-cell-like cells that can form other cell types.

Leprosy is caused by the bacterium Mycobacterium leprae, which infects Schwann cells that insulate nerve cells. When Anura Rambukkana at the University of Edinburgh, UK, and his colleagues infected mouse Schwann cells with the bacterium, they found that the cells expressed genes typical of an earlier developmental stage. After they were injected into mouse muscle, these stem-cell-like cells turned into muscle cells, and the bacteria spread to neighbouring muscle tissue. The stem-cell-like cells also transferred bacteria to immune cells called macrophages, which spread the infection further.

Understanding how M. leprae reprograms cells could inform treatment strategies, as well as provide tools for regenerative medicine, the authors say.

Cell 152, 51–67 (2013)