Biology subjects

Foley, E.

Publications and source records attributed to Foley, E..

3 recordsLinked to original sources

bioRxiv2018

The Immune Deficiency Pathway Attenuates Insulin Signaling to Protect Against Infection.

Immune and metabolic pathways collectively influence host responses to microbial invaders, and mutations in one pathway frequently disrupt activity in the other. We used the Drosophila model to characterize metabolic homeostasis in flies with modified Immune Deficiency (IMD) pathway activity. The IMD pathway is very similar to the mammalian Tumor Necrosis Factor-alpha pathway, a key regulator of vertebrate immunity and metabolism. We found that persistent activation of IMD resulted in hyperglycemia, depleted fat reserves, and developmental delays, implicating IMD in metabolic regulation. Consistent with this hypothesis, we found that imd mutants weigh more, are hyperlipidemic, and have impaired glucose tolerance. To test the importance of metabolic regulation for host responses to bacterial infection, we challenged insulin pathway mutants with lethal doses of several Drosophila pathogens. We found that loss-of-function mutations in the insulin pathway impacted host responses to infection in a manner that depends on the route of infection, and the identity of the infectious microbe. Combined, our results support a role for coordinated regulation of immune and metabolic pathways in host containment of microbial invaders.

immunology↗

bioRxiv2018

Commensal-Pathogen Competition Impacts Host Viability

While the structure and regulatory networks that govern the activity of the type-six secretion system (T6SS) of Vibrio cholerae are becoming increasingly clear, we know less about the role of the T6SS in disease. Under laboratory conditions, V. cholerae uses the T6SS to outcompete many Gram-negative species, including other V. cholerae strains and human commensal bacteria. However, the role of these interactions has not been resolved in an in-vivo setting. We used the Drosophila melanogaster model of cholera to define the contribution of the T6SS to V. cholerae pathogenesis. Here, we demonstrate that interactions between the T6SS and host commensals impact pathogenesis. Inactivation of the T6SS, or removal of commensal bacteria attenuates disease severity. Re-introduction of the Gram-negative commensal bacterium Acetobacter pasteurianus into a germ-free host is sufficient to restore T6SS-dependent pathogenesis. Together, our data demonstrate that the T6SS acts on commensal bacteria to promote the pathogenesis of V. cholerae.

microbiology↗

bioRxiv2016

Constitutive Immune Activity Promotes Tumorigenesis in Drosophila Intestinal Progenitor Cells.

Gut innate immune defenses contain bacterial populations and protect the host interior from invasive microbes. Although excess intestinal immune activity frequently promotes inflammatory illnesses, we know little about the consequences of chronic innate immune activity exclusively in endodermal gut cells of an otherwise normal animal. To address this question, we generated a transgenic line that allows us to activate inflammatory signals in adult fly intestinal progenitor cells. We found that constitutive immune activity in intestinal progenitors disrupts expression of homeostatic regulators such as Notch signal transduction pathway components and induces hyperplasia throughout the gut. Consistent with these observations, we found that persistent immune signaling interferes with progenitor cell differentiation and exacerbates the formation of Notch-dependent intestinal tumors. These findings uncover a novel link between constitutive immune activity and tumorigenesis in intestinal stem cells.

immunology↗