Mary O'Riordan, Ph.D.
Assistant Professor,
Department of Microbiology and Immunology
oriordan@umich.edu

Our research interests focus on the interaction between host cells and
bacterial pathogens that live within the cell. Macrophages, an important
niche for many intracellular pathogens, can sense unique bacterial molecules
within the cytosol. Triggering of this cytosolic surveillance pathway
results in a characteristic pattern of gene expression that includes
cytokines and other pro-inflammatory target genes. Using the Gram-positive
cytosolic bacterium, Listeria monocytogenes as a model pathogen, we are
identifying signaling molecules and transcriptional regulators that are
specific to the innate cytosolic surveillance pathway. In addition, we
study mechanisms of innate immunity to vacuolar bacterial pathogens, such as
Salmonella enterica serovar typhimurium. Lastly, we are investigating the
intracellular life cycle of Listeria monocytogenes in murine dendritic
cells. Listeria grows explosively in almost all cell types, but fails to
grow in the cytosol of dendritic cells. Current studies are focused on
identifying mechanisms by which dendritic cells restrict the growth of
intracellular pathogens.

Representative Publications

Keeney KM, Stuckey JA, O'riordan MX. LplA1-dependent utilization of host lipoyl peptides enables Listeria cytosolic growth and virulence.
Mol Microbiol . 2007 Oct 1; [Epub ahead of print]

A. Radtke, L. Delbridge S. Balachandran, G. Barber and M. O’Riordan. 2007.
TBK1 protects vacuolar integrity during intracellular bacterial infection. PLoS Pathog . 2007 Mar;3(3):e29.

L. Delbridge and M. O’Riordan. Innate Recognition of Intracellular
Bacteria. Current Opinion in Immunology. 2007 Feb;19(1):10-6.

A. Radtke and M. O’Riordan. Innate Resistance to Intracellular Bacterial
Pathogens. 2006. Cellular Microbiology. Nov;8(11):1720-9.

V. Auerbuch, D. Brockstedt, N. Meyer-Morse, M. O'Riordan and D.A. Portnoy.
2004. Mice lacking the Type I interferon receptor are resistant to Listeria
monocytogenes. J Exp Med. 200(4):527-33.

R. McAffrey, P. Fawcett, M. O'Riordan, K.D. Lee, E. A. Havell, P. Brown and
D. A. Portnoy. 2004. A Cytosol-specific Program of Gene Expression Induced
by Gram-positive Intracytosolic Bacteria. Proc. Natl. Acad. Sci.101(31):11386-91.

M. O'Riordan, M. A. Moors and D. A. Portnoy. 2003. Listeria intracellular growth
and virulence require host-derived lipoic acid. Science. 302(5644): 462-4.

M. O'Riordan, C. H. Yi, R. Gonzales, K. D. Lee and D. A. Portnoy. 2002.
Innate Recognition of Bacteria by a Macrophage Cytosolic Surveillance
Pathway. Proc. Natl. Acad. Sci. 99(21): 13861-13866.

M. O'Riordan and D. A. Portnoy. 2002. The Host Cytosol: Front-line or Home
Front? Trends in Microbiology 10(8): 361-364.

M. O'Riordan and R. Grosschedl. 2000. Transcriptional Regulation of Early
B-lymphocyte Differentiation. Immunological Reviews 175:94-103.

T. Reya, M. O'Riordan, R. Okamura, E. Devaney, K. Willert, R. Nusse and R.
Grosschedl. 2000. Wnt Signaling Regulates B Lymphocyte Proliferation through a LEF-1 Dependent Mechanism. Immunity 13:15-24.

M. O'Riordan and R. Grosschedl. 1999. Coordinate Regulation of B Cell
Differentiation by the Transcription Factors EBF and E2A. Immunity 11: 21-31.

M. Sigvardsson, M. O'Riordan and R. Grosschedl. 1997. EBF and E47
Collaborate to Induce Expression of the Endogenous Immunoglobulin Surrogate Light Chain Genes. Immunity 7: 25-36.