Advances in Immunology and Microbiology Seminar Series: Katie Tseng and Jyoti Kashyap
About the event
Featuring research in the areas of:
Epidemiology | Infectious Disease | Disease Ecology | Drug Discovery | Virology |
Global Health | Vector-Borne Disease | Pathology
The Advances in Immunology & Microbiology seminar series is a weekly forum that brings together scientists from diverse fields and disciplines across the College of Veterinary Medicine to discuss research advances in the broad areas of immunology, microbiology, infectious diseases, and global health. Seminars feature student speakers from the Immunology & Infectious Disease (IID) doctoral program, IID-affiliated postdoctoral researchers and faculty, intramural speakers from across the university, and extramural speakers.
PRESENTER: Katie Tseng, PhD Candidate; Mentor: Dr. Pilar Fernandez, Paul G. Allen School for Global Health
TITLE: Analysis of kinship networks in a rural endemic setting for human Trypanosoma cruzi infection
ABSTRACT: In the Gran Chaco ecoregion of northern Argentina, where Chagas disease is hyperendemic, previous research suggests that human mobility patterns may contribute to the heterogeneous distribution of human Trypanosoma cruzi infection. For example, travel between households driven by kinship ties may facilitate the passive transport of triatomine vectors over long distances or expose individuals to infected vectors outside their homes. To explore the social connectivity of households in the context of T. cruzi transmission, we reconstructed the human kinship network across seven rural communities in Pampa del Indio, Chaco Province, Argentina. While many kin relationships were spatially aggregated within the same community, connections also extended across communities. Furthermore, the average proportion of household connectivity varied with distance, suggesting that social structure may influence T. cruzi transmission dynamics independently of spatial structure. Future analyses will integrate these findings with T. cruzi serosurvey data to assess whether human kinship network properties predict risk of T. cruzi infection in humans.
PRESENTER: Dr. Jyoti Kashyap; Mentor: Dr. Arden Baylink, Veterinary Microbiology & Pathology
TITLE: A link between chemotaxis and carcinogenesis: Helicobacter pylori motility and chemotaxis restrict delivery of the oncogenic bacterial effector CagA within the gastric glands
ABSTRACT: Helicobacter pylori is a major cause of gastric cancer and uses chemotaxis, i.e. directed swimming motility to infiltrate the gastric glands. H. pylori promotes cancer development by injecting cytotoxin-associated gene-A (CagA) effector into gastric glands, dysregulating stem cells and leading to metaplasia and dysplasia. Since these long-lived cells reside deep within the glands, we wondered whether swimming motility and chemotaxis are required for H. pylori to access this cell population, and thus, be involved in gastric cancer development.
To test this, we developed swine gastric explants as a metabolically inert reductionist model system, enabling us to easily visualize all gastric mucosa cells that become CagA+. Using fluorescence microscopy, we compared H. pylori colonization patterns and CagA delivery of H. pylori strains G27 and SS1. We found both strains effectively colonize the gastric surface and pits, and a minority population deeply infiltrates into the gastric gland base, like human infections. Isogenic mutants deficient in chemotaxis generally infiltrated more deeply into the glands.
In swine infections in vivo, a system that models key anatomical and physiological features of the human stomach, chemotaxis-deficient strains caused more severe gastritis and ulceration than WT. Together, our data suggest that: (1) chemotaxis restricts gland infiltration and limits H. pylori pathology, which may assist the pathogen in its goal to be a lifelong colonizer of its human host, and (2) although it may take decades for the oncogenic effects of CagA to manifest, cellular dysregulation by this bacterial effector may begin immediately upon infection