Gerald Duhamel, DVM, PhD, DACVP
Department of Biomedical Sciences, College of Veterinary Medicine
Professor of Anatomic Pathology
Department of Biomedical Sciences
Cornell University College of Veterinary Medicine
Veterinary Research Tower T4012A, Box 11
Ithaca, NY 14853
My laboratory focuses on understanding molecular mechanisms of host-parasite interactions and their relationship to susceptibility or resistance against diseases, particularly within the framework of enteric bacterial infections in animal models of human diseases.
Over the past 30 years, I have been engaged in basic and applied biomedical research aimed at characterizing the molecular basis of microbial pathogenesis and host defense with practical applications to diagnosis and control of enteric diseases of animals and human beings. As a board-certified Diplomate of the American College of Veterinary Pathologists and a Professor of Anatomic Veterinary Pathology, I oversee a research program focused on microbial pathogenesis of enteropathogenic Campylobacter and Helicobacter bacterial species in humans and animals, including laboratory mice and non-human primates and polymicrobial infections caused by these pathogens together with the intestinal spirochete Brachyspira pilosicoli. Specifically, I am interested in defining molecular mechanisms of bacterial virulence and host-pathogen interactions in cultured cell and animal models, phenotypic and genotypic bases of microbial diversity, and functional genomics. For the past several years my research efforts have focused on mechanisms of a novel bacterial genotoxin cytolethal distending toxin (CDT)-induced DNA damage response (DDR) within the context of intestinal disease of human and animals. I also collaborate with a wide range of basic research scientists by providing pathology assessment of various laboratory mouse models primarily of intestinal diseases.
Presently, we seek to extend our observations to (i) uncover the natural history and biology of Brachyspira and EHS polymicrobial infections in various hosts, (ii) define the genomic diversity, population structure, and zoonotic potential of Brachyspira pilosicoli isolated from animal and environmental sources, and (iii) define the role of cytolethal distending toxin, a virulence factor found in EHS and several other related enteric bacterial pathogens including Campylobacter species associated with foodborne bacterial illnesses worldwide.
Given the broad range of host species where Brachyspira pilosicoli is found intimately adherent along the colonic epithelium together with EHS, we hypothesize that cross-talk between these bacteria leads to coordinate expression of genes involved in colonization and breakdown of colonic mucosal epithelial barrier function. We anticipate that this host-polymicrobial pathogen interaction model system will uncover novel and important mechanisms of colonic mucosal inflammatory and immune activation relevant to understanding the pathogenesis of inflammatory bowel disease.
Animal and cultured cell infection models and advanced microscopy
Fluorescent cytometry and laser scanning confocal microscopy for assessment of (i) bacterial adherence, invasion, and cytotoxicity in cultured human and animal intestinal epithelial cells, (ii) bacterial uptake and intracellular trafficking in human monocytic and mouse macrophage cells, (iii) analysis of lymphocyte subsets, (iv) stable and transient protein expression in eukaryotic cell lines, and (v) fluorescent in situ hybridization (FISH) of bacterial 16S and 23S rRNA genes. Light, transmission, scanning electron microscopy, and laser capture microdissection of tissues taken from spontaneous and experimentally-induced enteric diseases in animal models of human diseases.
Microbial molecular biology and immunology
Aerobic, microaerobic, and anaerobic bacterial culture and isolation from diagnostic specimens, bacterial gene-specific amplification by PCR assays, phylogenetic sequence analysis, bacterial protein fractionation and amino acid sequencing, recombinant fusion-protein overexpression/purification, production of antibodies to purified and synthetic peptide conjugates, ELISA and Western blot analyses, colorimetric bacterial nuclease and protease assays, cytokine quantitation by bead-array flow cytometry, immunohistochemical staining of pathogenic bacteria and host immune system components, and fluorescent activated cell sorting.
PhD, Comparative Pathology, School of Veterinary Medicine, University of California-Davis, 1986 (Advisor: Dr. Bennie I. Osburn)
Residency, Veterinary Anatomic Pathology, School of Veterinary Medicine, University of California-Davis, 1980-1982
1976-80 Doctor of Veterinary Medicine, University of Montreal, 1980
- Demeter EA, Canales GM, Scrivani PV, Duhamel GE. 2017. Pathology in Practice - Granulomatous bronchopneumonia, osteomyelitis, fasciitis and myositis with yeasts consistent with Blastomyces species in a 3-year-old Doberman pincher. J Am Vet Med Assoc in press.
- Pecoraro HL, Thompson B, Duhamel GE. 2017. Histopathological case definition of naturally-acquired Salmonella enterica serovar Dublin infection in young Holstein cattle in the Northeastern United States. J Vet Diagn Invest, in press.
- Im JY, Sokol SA, Duhamel GE. 2017. Gastric dilatation associated with gastric colonization with Sarcina-like bacteria in an adult cat with chronic enteritis. J Am Animal Hospital Assoc, in press.
- Sun S, Lourie R, Cohen SB, Ji Y, Goodrich JK, Poole AC, Ley RE, Denkers EY, McGuckin MA, Long Q, Duhamel, GE, Simpson KW, Qi L. 2016. Epithelial Sel1L is required for the maintenance of intestinal homeostasis. Molecular Biology of the Cell 27:483-490.
- Sun S, Shi G, Sha H, Ji Y, Han X, Shu X, Ma H, Inoue T, Gao B, Kim H, Bu P, Guber RD, Shen X, Lee A-H, Iwawaki T, Paton AW, Paton JC, Fang D, Tsai B, Yates III JR, Wu H, Kersten S, Long Q, Duhamel, GE, Simpson KW, Qi L. 2015. IRE1α is an endogenous substrate of endoplasmic reticulum-associated degradation. Nature Cell Biology 17:1546-1555.
- Rodriguez-Rivera LD, Bowen BM, den Bakker HC, Duhamel GE, Wiedmann M. 2015. Characterization of the cytolethal distending toxin (typhoid toxin) in non-typhoidal Salmonella serovars. BMC Gut Pathogens 7:19-25.
- Licitra BN, Whittaker, GR, Dubovi EJ, Duhamel GE. 2014. Genotypic characterization of canine enteric coronaviruses associated with fatal canine neonatal enteritis in the United States. J Clin Microbiol 52:4230-4238.
- Licitra BN, Duhamel GE, Whittaker GR. 2014. Canine enteric coronaviruses: Emerging viral pathogens with distinct recombinant spike proteins. Viruses 6:3363-3376.
- Ji Y, Sun S, Goodrich JK, Kim H, Poole AC, Duhamel GE, Ley RE, Qi L. 2014. Diet-induced alterations in gut microflora contribute to lethal pulmonary damage in TLR2/TLR4 deficient mice. Cell Reports 8(1):137-419.
- Sun S, Shi G, Han X, Francisco AB, Ji Y, Mendonça N, Liu X, Locasale JW, Simpson KW, Duhamel GE, Kersten S, Yates III JR, Long Q, Qi L. 2014. Sel1L is indispensable for mammalian ERAD, ER homeostasis and survival. Proc Natl Acad of Sci, 111(5): E582–E591.
- Sipka AS, Klaessig S, Duhamel GE, Skidmore A, Swinkels JM, Rainard P, Schukken Y. 2014. Impact of intramammary treatment on gene expression profiles in bovine Escherichia coli mastitis. PLoS One 9:e85579.
Awards and Honors
American College of Veterinary Pathologists
American Veterinary Medical Association
American Society for Microbiology
American Association of Veterinary Laboratory Diagnosticians
Conference of Research Workers in Animal Diseases
Department of Biomedical Sciences
Graduate Field of Comparative Biomedical Sciences
Graduate Field of Immunology