Hydrogen sulfide heightens disease in tuberculosis, suggesting a new therapeutic target

BIRMINGHAM, Ala. - A new culprit -- hydrogen sulfide -- has been found for the deadly infectious disease tuberculosis. Hydrogen sulfide gas is known for its rotten egg smell, yet it has normal physiological roles in the human body to communicate among cells.

When tuberculosis bacteria invade the lung, however, the amounts of hydrogen sulfide in the lung microenvironment appear to greatly increase, and this makes the microbe more virulent and better able to block the body's protective immune response, according to research led by Andries "Adrie" Steyn, Ph.D., a University of Alabama at Birmingham professor of microbiology.

The source of this hydrogen sulfide? Mycobacterium tuberculosis bacteria, or Mtb, are able to induce human macrophage immune cells to produce more hydrogen sulfide. Thus, Mtb exploits macrophage metabolism to increase Mtb virulence. During the disease, Mtb grows and safely persists inside macrophages, the immune cells that normally should have protected the lungs by killing the engulfed bacteria. In a bacterial sense, the Mtb become wolves in sheep's clothing.

"To the best of our knowledge," Steyn said, "no study has yet reported a role for host hydrogen sulfide in the control of bacterial disease."

3-MAR-2020

https://www.eurekalert.org/