Google Play icon

Bacteria stops novel “cell suicide system” to promote infection and proliferation

Posted June 5, 2013
This news or article is intended for readers with certain scientific or professional knowledge in the field.

Dr. Chihiro Sasakawa (Emeritus Professor), Taira Kobayashi (Institute of Medical Science), and their teams discovered a novel cellular defense mechanism against bacterial infections. By understanding this mechanism, it may help stop serious infectious diseases caused by pathogenic bacteria such as Shigella, Salmonella, and pathogenic-E. coli.

Individual cells have various functions that are important for the survival of the organism. For example, when cells are threatened by cancer or infection, they will normally destroy themselves. They cause “cell suicide” to prevent further proliferation of the cancer or infection and allow the organism to survive. This “suicide system” is well-managed by an intracellular enzyme family called Caspase. However, not all aspects of Caspase function are known.

This research shows the Shigella bacteria inhibit Caspase-4 (a member of the Caspase family) with an inhibitor called OspC3, which prevents cell suicide. Specifically, OspC3 binds to Caspase-4 and stops its activation by closing the lid on the putative catalytic pocket. Interestingly, the OspC3’s function does not work for the other Caspase family enzymes; therefore, OspC3 selectively inhibits Caspase-4-dependent cell death.

Research was also carried out with a mutant form of Shigella that lacked OspC3. In this case, a previously unreported form of cell suicide occurred and Shigella was eliminated from cells and animals. A Shigella OspC3-deficient mutant caused Caspase 4-dependent inflammatory epithelial cell death (pyroptosis). The research shows the danger of OspC3, which allows Shigella infected cells to spread even in harsh host environments.

These results have brought light to a novel defense mechanism against intestinal infectious bacteria. This discovery will further understanding of the role of Caspace-4 in a host’s defense mechanism as well as bacterial infection and proliferation. Moreover, the discovery of OspC3 and the Shigella OspC3-deficient mutant is expected to help in the development of a drug for Caspace-4 related diseases such as sepsis.

Source: University of Tokyo

Featured news from related categories:

Technology Org App
Google Play icon
85,387 science & technology articles

Most Popular Articles

  1. New treatment may reverse celiac disease (October 22, 2019)
  2. "Helical Engine" Proposed by NASA Engineer could Reach 99% the Speed of Light. But could it, really? (October 17, 2019)
  3. New Class of Painkillers Offers all the Benefits of Opioids, Minus the Side Effects and Addictiveness (October 16, 2019)
  4. The World's Energy Storage Powerhouse (November 1, 2019)
  5. Plastic waste may be headed for the microwave (October 18, 2019)

Follow us

Facebook   Twitter   Pinterest   Tumblr   RSS   Newsletter via Email