Tuberculosis results in 2 million deaths each year world wide, and about 8 million new cases are reported annually. As such, it is the leading cause of death from a bacterial disease. Now, Gareth Griffiths and colleagues, in a study published in the September issue of Nature Cell Biology, suggest that dietary lipids may help overcome such infections in animal models.
The causative agent of tuberculosis - a bacterium called Mycobacterium tuberculosis - infects white blood cells where it is held in a specialized membraneous sac called phagosomes. Normally, the phagosome would mature into a compartment containing degradative enzymes that would break down phagosomal contents. Although scientists have known for some time that Mycobacterium blocks phagosome maturation, exactly how the bacterium does this is not known.
This new study might not only explain how the bacterium could subvert normal phagosome maturation, but might also suggest new avenues for treating tuberculosis. The authors show that phagosomes containing the bacterium are unable to support the nucleation of actin, a component of the cell’s skeletal network that seems to be important for phagosome maturation. Most remarkably, this study shows that certain natural lipids can reverse the inhibition of actin nucleation by the infected phagosome, stimulate phagosomal maturation in infected cells, and lower the survival rate of the pathogen in infected cells.
Whether dietary lipids might one day become a feasible way to treat tuberculosis remains to be determined. However, based on their findings, the authors recommend testing the effectiveness of these lipids to overcome infections in animal models.
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