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Tufts Public Health

John Leong

Edith Rieva and Hyman S. Trilling Professor of Molecular Biology & Microbiology
Department: Molecular Biology and Microbiology
Programs: Biomedical Sciences
Laboratory: Arnold 511E

John Leong

Edith Rieva and Hyman S. Trilling Professor of Molecular Biology & Microbiology
Department: Molecular Biology and Microbiology
Programs: Biomedical Sciences
Laboratory: Arnold 511E

Phone 617-636-0488
Lab phone: 617-636-0906
Office: Arnold 511E
Campus: Boston

Links

Biography

​In causing disease, bacterial pathogens establish an infectious niche and generate damage within the mammalian host. We investigate three bacterial pathogens to understand the host-microbe interactions that promote colonization and disease, and then, during resolution of infection, mediate microbial clearance. Enterohemorrhagic Escherichia coli O157:H7 is a food-borne intestinal pathogen that that injects into intestinal epithelial cells proteins that stimulate actin polymerization directly beneath bound bacteria. We are studying the action of these proteins to understand how interactions between these bacteria and the intestinal epithelium promote colonization and disease, as well as to gain insight into fundamental mechanisms of actin assembly in mammalian cells. Streptococcus pneumoniae, an important cause of lung infection, and pathogenic spirochetes, such as the Lyme disease spirochete Borrelia burgdorferi, each can establish a localized infection but are also capable of spreading throughout the host. We investigate the microbe-host cell interactions that promote tissue invasion and systemic spread, as well as the components of the host immune response that contribute to immune protection and bacterial clearance.

Education

  • BA, Biology, Brown University
  • MD, PhD, Molecular Biology, Brown University
  • Postdoctoral Training, Tufts University School of Medicine

Research synopsis

In causing disease, bacterial pathogens establish an infectious niche and generate damage within the mammalian host. We investigate three bacterial pathogens to understand the host-microbe interactions that promote colonization and disease, and then, during resolution of infection, mediate microbial clearance. Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a food-borne intestinal pathogen that that colonizes the intestinal epithelium and produces shiga toxin, a which is responsible for cause systemic disease, including renal failure. We developed a murine model of EHEC infection to understand mechanisms of colonization and disease, as well as to develop therapeutic or preventative interventions. Streptococcus pneumoniae, an important cause of lung infection, causes damage largely by inducing a vigorous host inflammatory response, and we are investigating how the pathogen is recognized by the host with a goal of modulating the acute immune response to mitigate disease. Finally, the Lyme disease spirochete Borrelia burgdorferi, each can establish a localized infection but are also capable of spreading throughout the host. We investigate spirochete-host interactions that promote bloodstream survival and tissue invasion.

 

Publications

Lin YP, Leong JM. 2017. Characterization of Borrelia burgdorferi binding to mammalian cells and extracellular matrix. Methods Mol Biol 1690: 57-67.

Caine JA, Lin YP, Kessler JR, Sato H, Leong JM, Coburn J. 2017. Borrelia burgdorferi outer surface protein C (OspC) binds complement component C4b and confers bloodstream survival. Cell Microbiol. Epub ahead of print.

Bhowmick R, Clark S, Bonventre JV, Leong JM, McCormick BA 2017. Cytosolic phospholipase A2α promotes pulmonary inflammation and systemic disease during Streptococcus pneumoniae infection. Infect Immun. Epub ahead of print.

Bou Ghanem EN, Lee JN, Joma BH, Meydani SN, Leong JM, Panda A. 2017. The Alpha-tocopherol form of Vitamin E boosts elastase activity of human PMNs and their ability to kill Streptococcus pneumoniae. Front Cell Infect Microbiol. 7:161.

Flowers LJ, Bou Ghanem EN, Leong JM. 2016. Synchronous disease kinetics in a murine model for enterohemorrhagic E. coli infection using food-borne inoculation. Front Cell Infect Microbiol. 6:138. Synchronous Disease Kinetics in a Murine Model for Enterohemorrhagic E. coli Infection Using Food-Borne Inoculation.

Jandhyala DM, Wong J, Mantis NJ, Magun BE, Leong JM, Thorpe CM. 2016. A novel Zak knockout mouse with a defective ribotoxic stress response. Toxins (Basel) 8: 9.