Meta Kuehn (Primary)

Associate Professor of Biochemistry
Associate Professor of Molecular Genetics & Microbiology
Duke Cancer Institute Member
Kuehn Lab, Primary Faculty
Research Interests: 
Membrane Biochemistry, Microbial Pathogenesis Mechanisms of Toxicity, Host/Microbe Interactions, Protein Secretion Mechanisms 
Lab Location
Nanaline Duke Room 221, Durham, NC 27710
Office Location

Nanaline Duke Room 220A Durham, NC 27710

(919) 684-2545

Enterotoxigenic E. coli (ETEC) causes traveler's diarrhea and infant mortality in underdeveloped countries, and Pseudomonas aeruginosa is an opportunistic pathogen for immunocompromised patients. Like all gram negative bacteria studied to date, ETEC and P. aeruginosa produce small outer membrane vesicles that can serve as delivery "bombs" to host tissues. Vesicles contain a subset of outer membrane and soluble periplasmic proteins and lipids. In tissues and sera of infected hosts, vesicles have been observed to bud from the pathogen and come in close contact with epithelial cells. Despite their association with disease, the ability of pathogenic bacteria to distribute an arsenal of virulence factors to the host cells via vesicles remains relatively unexplored. 

In our lab, we focus on the genetic, biochemical and functional features of bacterial vesicle production. Using a genetic screen, we have identified genes essential in the vesiculation process, we have identified specific proteins that are enriched in vesicles, and we have identified critical molecules that govern the internalization of vesicles into host cells. Using biochemical analysis of purified vesicles from cell-free culture supernatants, we have found that heat-labile enterotoxin, an important virulence factor of ETEC, is exported from the cells bound to the external surface of vesicles. Presented in this context, it is able to mediate the entry of the entire ETEC vesicle into human colorectal tissue culture cells. We have also discovered that the ability of vesicles to bind to specific cell types depends on their strain of origin: for example, P. aeruginosa vesicles produced by a strain that was cultured from the lungs of a patient with Cystic Fibrosis adhered better to lung than to gut epithelial cells, whereas a strain that was isolated from sera showed no such preference for lung cells. The vesicles stimulate epithelial cells and macrophages to elicit a cytokine response that is distinct from that of LPS (a major component of the vesicles) alone. 

These studies will provide new insights into the membrane dynamics of gram-negative bacteria and consequently aid in the identification of new therapeutic targets for important human pathogens.

Education

Howard Hughes Postdoctoral Research Fellow, Biochemistry & Molecular Biology, University of California at Berkeley, 1994-1997
Postdoctoral Fellow Molecular Microbiology, Washington University, 1993
PhD Washington University, 1993
BS University of Washington, 1986

Publications
  1. Bonnington, KE, and Kuehn, MJ. "Protein selection and export via outer membrane vesicles." Biochim Biophys Acta 1843, no. 8 (August 2014): 1612-1619. (Review)  Full Text Link to Item
  2. Bonnington, KE, and Kuehn, MJ. "Protein selection and export via outer membrane vesicles." Biochimica et Biophysica Acta - Molecular Cell Research 1843, no. 8 (2014): 1612-1619.  Full Text
  3. Schwechheimer, C, and Kuehn, MJ. "Synthetic effect between envelope stress and lack of outer membrane vesicle production in Escherichia coli." J Bacteriol 195, no. 18 (September 2013): 4161-4173.  Full Text  Link to Item
  4. Schwechheimer, C, Sullivan, CJ, and Kuehn, MJ. "Envelope control of outer membrane vesicle production in Gram-negative bacteria." Biochemistry 52, no. 18 (May 7, 2013): 3031-3040.  Full Text  Link to Item
  5. Chutkan, H, MacDonald, I, Manning, A, and Kuehn, MJ. "Quantitative and qualitative preparations of bacterial outer membrane vesicles." Methods in Molecular Biology 966 (2013): 259-272.  Full Text