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College of Veterinary Medicine

Philip R. Hardwidge

 Associate Professor

B.S. Summa cum laude 1997, University of Illinois, Urbana, IL
Ph.D. 2002, Mayo Clinic Graduate School, Rochester, MN
Post-doctoral Fellow 2005, University of British Columbia, Vancouver, Canada

Phone:(785) 532-2506
Fax: (785) 532-4851
Email: hardwidg@vet.k-state.edu


My laboratory is interested in understanding, treating, and preventing diarrheal disease caused by bacterial pathogens. We study several virotypes of Escherichia coli that cause diarrhea and malnutrition in humans and livestock, including E. coli O157:H7, non-O157 STEC, and enterotoxigenic E. coli (ETEC). These pathogens, as well as other enteric bacteria that use contact-dependent secretion systems, represent important threats to food safety, biosecurity, and animal health. In many cases, vaccines are not available or are ineffective, and the basic molecular microbiology of the host-pathogen interaction is relatively poorly understood. Additionally, bacterial virulence proteins utilize many molecular mechanisms that are also conserved among viruses of importance to biosecurity. My research team has discovered several mechanisms by which bacterial proteins subvert the host innate immune system to promote bacterial colonization and transmission. We are directing our knowledge of these proteins and their mammalian targets to innovative studies of metabolic syndromes, autoimmune disorders, and cancer. We are also developing proteomic techniques to identify vaccine targets in other organisms. I direct a dynamic and diverse team of postdoctoral fellows, Ph.D. students, technicians, and visiting research scholars to achieve these goals.

Current and Completed NIH Funding

R01 AI099002                         NIH/NIAID       Bacterial effectors targeting the IKK/NF-kB pathway
The goal of this study is to characterize E. coli virulence proteins that disrupt the host immune response.

R21 AI101231                         NIH/NIAID       An ETEC protein that antagonizes the NF-kB pathway
The goal of this study is to characterize how ETEC antagonizes pro-inflammatory signaling pathways.

R21 AI092266                         NIH/NIAID       Reverse vaccinology of enterotoxigenic E. coli
The goal of this study was to identify protective antigens for future development of ETEC vaccines.

R21 AI093913                         NIH/NIAID       Bacterial effector inhibition of type I interferon
The goal of this study was to determine how bacterial effectors inhibit type I interferon production.

R03 CA155868                       NIH/NCI          Delivery of a bacterial inhibitor of NF-kB to colon tumors
The goal of this study was to develop technologies to inhibit NF-kB activity in colon cancers.

R56 AI087686                         NIH/NIAID       Disruption of NF-kB signaling by diarrheagenic Escherichia coli
The goal of this study was to define the role of E. coli O157:H7 NleH proteins in disrupting NF-kB signaling.

R03 AI087923                         NIH/NIAID       Bacterial effector subversion of host protein trafficking
The goal of this study was to define how bacterial pathogens exploit eukaryotic secretory pathways.

R03 AI076227                         NIH/NIAID       Host subversion by E. coli O157:H7 effector proteins
The goal of this study was to identify E. coli virulence proteins that inhibit innate immunity.

R15 AI070339                         NIH/NIAID       Emerging virulence factors in diarrheagenic E. coli pathogenesis
The goal of this study was to define the role of the NleF protein in enterohemorrhagic E. coli virulence.

Selected publications

Hardwidge PR,et al. Proteomic analysis of the intestinal epithelial cell response to enteropathogenic Escherichia coli. Journal of Biological Chemistry. 2004 May 7;279(19):20127-36. PMID: 14988394

Deng W, et al.  Regulation of type III secretion hierarchy of translocators and effectors in attaching and effacing bacterial pathogens. Infection and Immunity. 2005 Apr;73(4):2135-46. PMC1087438 (see Faculty of 1000)

Hardwidge PR,et al. Modulation of host cytoskeleton function by the enteropathogenic Escherichia coli and Citrobacter rodentium effector protein EspG. Infection and Immunity. 2005 May;73(5):2586-94. PMC1087329

Kim J, et al. The bacterial virulence factor NleA inhibits cellular protein secretion by disrupting mammalian COPII function. Cell Host and Microbe. 2007 Sep 13;2(3):160-71. PMID: 18005731 (see Faculty of 1000)

Gao X, et al. Bacterial effector binding to ribosomal protein S3 subverts NF-kB function. PLoS Pathogens 2009. Dec;5(12):e1000708. PMC2791202

Johnson AM, et al. Heat-labile enterotoxin promotes Escherichia coli adherence to intestinal epithelial cells. Journal of Bacteriology. 2009 Jan;191(1):178-86. PMC2612432

Fleckenstein JM, et al.  Molecular mechanisms of enterotoxigenic Escherichia coli infection, Microbes and Infection, 2010. Feb;12(2):89-98. PMID: 19883790

Shames SR, et al.  The pathogenic E. coli type III effector EspZ interacts with host CD98 and facilitates host cell prosurvival signaling. Cellular Microbiology, 2010, Sep 1; 12(9):1322-39. PMID: 20374249

Wan F, et al. IKKb phosphorylates RPS3 to regulate its nuclear translocation and NF-kB specifier function, Nature Immunology 2011 Apr;12(4):335-43. PMID: 21399639 (see Faculty of 1000)

Wang X, et al. Heat-labile enterotoxin-induced activation of NF-kappaB and MAPK pathways in intestinal epithelial cells impacts enterotoxigenic Escherichia coli (ETEC) adherence, Cellular Microbiology, 2012 Aug;14(8):1231-41. PMID: 22452361

Pham T, et al.  Functional differences and interactions between the E. coli type III secretion system effectors NleH1 and NleH2, Infection & Immunity, 2012 Jun;80(6):2133-40. PMID: 22451523

Wang X & Hardwidge PR. Enterotoxigenic Escherichia coli (ETEC) prevents host NF-kB activation by targeting IkBa polyubiquitination, Infection & Immunity, 2012, Dec;80(12):4417-25. PMID: 23027537

Gao X, et al.  NleB, a bacterial effector with glycosyltransferase activity, targets GAPDH function to inhibit NF-kB activation, Cell Host & Microbe, 2013, Jan;13(1):87-99. PMID: 23332158

Pham T, et al. Escherichia coli virulence protein NleH1 Interaction with
the v-crk Sarcoma Virus CT10 Oncogene-Like Protein (CRKL) Governs NleH1 Inhibition of the Ribosomal Protein S3 (RPS3)/NF-kappaB Pathway, Journal of Biological Chemistry, 2013, Nov 29;288(48):34567-74. PMID: 24145029

Rüter C & Hardwidge PR. “Drugs from Bugs”: Bacterial effector proteins as promising biological (immune-) therapeutics, FEMS Microbiology Letters, 2014, 351:126-132. PMID: 24261744

Feuerbacher LA & Hardwidge PR. Influence of NleH effector expression, host genetics, and inflammation on Citrobacter rodentium colonization in mice, Microbes and Infection, 2014, May;16(5):429-33. PMID: 24613200

Kumar A, et al.  Protective enterotoxigenic Escherichia coli antigens in a murine intranasal challenge model, PLoS Neglected Tropical Diseases, 2015, Aug 5;9(8):e0003924. PMID:26244636