Salk Institute
Janelle S. Ayres
Assistant Professor
Nomis Foundation Laboratories for Immunobiology and Microbial Pathogenesis
Janelle S. Ayres

Assistant Professor
Nomis Foundation Laboratories for Immunobiology and Microbial Pathogenesis

A major goal of my laboratory is to understand the defense strategies that enable a host to survive and even thrive when interacting with microbes. Knowledge of these defense mechanisms should lead to new treatments for infectious and inflammatory disease.

When faced with a microbial threat, such as infectious bacteria or viruses, hosts can utilize two defense strategies to protect their health: resistance and tolerance. Resistance mechanisms allow the host to directly attack microbes to eliminate the infection. Tolerance mechanisms minimize the harm caused by microbes, for example, by neutralizing toxins generated by the pathogen. Ayres provided some of the first evidence that tolerance is crucial for defense against infections in animals. Using fruit flies infected with lethal bacteria, she identified genes and environmental factors, such as diet, that are important for tolerance and, ultimately, survival of infections. Furthermore, she demonstrated that a single gene could influence both resistance and tolerance so that conditions that enhance tolerance against one type of infection also can influence resistance against a different pathogen.

Recently, to identify mechanisms involved in tolerance of bacteria, Ayres turned to the mammalian intestine. Humans and other mammals tolerate the colonization of trillions of bacteria in their intestines, and these communities perform important functions for host physiologies. Within this microbial community live pathobionts, microbial species that can cause disease when homeostasis is disrupted, such as when antibiotics disrupt this complex community. Pathobionts have been implicated in triggering a number of diseases, including Crohn's, rheumatoid arthritis and sepsis, an inflammatory response to infection that can lead to shock, organ failure and even death.

In studies in mice, Ayres found that antibiotics caused overgrowth of a multi-antibiotic-resistant E. coli pathobiont in the intestine, which spread to the lung and liver following intestinal injury. This triggered hypothermia and multi-organ damage—hallmarks of sepsis. She discovered that infection with this E. coli pathobiont leads to an overly exuberant inflammatory response and sepsis due to inappropriate stimulation of the inflammasome, a component of the body's innate immune system. Ayres suggests that the inflammasome may be a useful therapeutic target in patients harboring antibiotic-resistant pathobionts.

In the future, Ayres will expand her studies to determine the mechanisms that facilitate tolerance of pathobiont colonization in the intestine under homeostatic conditions. She will also determine how members of the intestinal microbial community influence tolerance of pathogenic infections. Her work will provide a better understanding of host defense against microbes and suggest new therapeutic approaches for treating infectious and inflammatory diseases.

Selected Publications

J.S. Ayres, N.J. Trinidad and R.E. Vance. Lethal inflammasome activation by a multi-drug resistant pathobiont upon antibiotic disruption of the microbiota. Nat Med (2012) Apr:22(18) 799-806.

E. Stone*, B. Fulton*, J.S. Ayres, L. Pham, J. Ziauddin, and M. Shirasu-Hiza The circadian clock protein Timeless regulates phagocytosis of bacteria in Drosophila. PLoS Pathogens (2012) Jan:8(1):e1002445.

J.S. Ayres and D.S. Schneider. The role of anorexia in resistance and tolerance to infections in Drosophila. PLoS Biology (2009) Jul:7(7): e1000150.

J.S. Ayres and D.S. Schneider. A signaling protease required for melanization in Drosophila affects resistance and tolerance of infections. PLoS Biology (2008) Dec;6(12):e305.

J.S. Ayres, N. Freitag and D.S. Schneider. Identification of Drosophila mutants altering defense and endurance of Listeria monocytogenes infection. Genetics (2008) Mar;178(3):1807-15.

M.D. Gordon, J.S. Ayres, D.S. Schneider and R. Nusse. Pathogenesis of Listeria-infected Drosophila wntD mutants is associated with elevated levels of the novel immunity gene edin. PLoS Pathogens (2008) Jul;4(7):e1000111.

M.M. Shirasu-Hiza, M.S. Dionne*, L.N. Pham*, J.S. Ayres* and D.S. Schneider. Interactions between circadian rhythm and immunity in Drosophila melanogaster. Current Biology (2007) May;17(10): R353-55. *authors contributed equally.

D.S. Schneider, J.S. Ayres*, S.M. Brandt*, A. Costa*, M.S. Dionne*, M.M. Gordon*, E.M. Mabery*, M.G. Moule*, L.N. Pham* and M.M. Shirasu-Hiza*. Drosophila eiger mutants are sensitive to extracellular pathogens. PLoS Pathogens (2007) March;3(3):e41. *authors contributed equally.

Invited Reviews

J. von Moltke, J.S. Ayres, E.M. Kofoed, J. Chavarria-Smith, R.E. Vance. Recognition of bacteria by inflammasomes. Annu Rev Immunol, under review.

J.S. Ayres and R.E. Vance. Cellular teamwork in antibacterial innate immunity. Nat Immunol (2012) Jan:19(2) 115-7.

J.S. Ayres and D.S. Schneider. Tolerance of infections. Annu Rev Immunol (2012):(30) 271-94.

J.S. Ayres and D.S. Schneider. Genomic dissection of microbial pathogenesis in cultured Drosophila cells. Trends Microbiol (2006) Mar;14(3):101-4.


D.S. Schneider and J.S. Ayres. Two ways to survive infection: what resistance and tolerance can teach us about treating infectious diseases. Nat Rev Immunol (2008) Nov;8(11):889-95.

Awards and Honors

  • 2010-2013 National Institute of Health Ruth L. Kirschstein National Research Service Award
  • 2008 The Professor Sidney Raffel Award
  • 2004 - 2007 National Science Foundation Graduate Student Fellowship
  • 2002 I.L. Chaikoff Memorial Award

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