Enteroaggregative E.coliAdherence to Human Heparan Sulfate Proteoglycans Drives Segment and Host Specific Responses to Infection

Enteroaggregative Escherichia coli(EAEC) is a significant cause of acute and chronic diarrhea, foodborne outbreaks, infections of the immunocompromised, and growth stunting in children in developing nations. There is no vaccine and resistance to antibiotics is rising. Unlike relatedE.colipathotypes that are often associated with acute bouts of infection, EAEC is associated with persistent diarrhea and subclinical long-term colonization. Several secreted virulence factors have been associated with EAEC pathogenesis and linked to disease in humans, less certain are the molecular drivers of adherence to the intestinal mucosa. We previously established human intestinal enteroids (HIEs) as a model system to study host-EAEC interactions and aggregative adherence fimbriae A (AafA) as a major driver of EAEC adherence to HIEs. Here, we report a large-scale assessment of the host response to EAEC adherence from all four segments of the intestine across at least three donor lines for fiveE.colipathotypes. The data demonstrate that the host response in the duodenum is driven largely by the infecting pathotype, whereas the response in the colon diverges in a patient-specific manner. Major pathways altered in gene expression in each of the four enteroid segments differed dramatically, with responses observed for inflammation, apoptosis and an overwhelming response to different mucin genes. In particular, EAEC both associated with large mucus droplets and specific mucins at the epithelial surface, binding that was ameliorated when mucins were removed, a process dependent on AafA. Pan-screening for glycans for binding to purified AafA identified the human ligand as heparan sulfate proteoglycans (HSPGs). Removal of HSPG abrogated EAEC association with HIEs. These results may mean that the human intestine responds remarkably different to distinct pathobionts that is dependent on the both the individual and intestinal segment in question, and uncover a major role for surface heparan sulfate proteoglycans as tropism-driving factor in adherence and/or colonization. Author summary E.coliis a significant cause of worldwide diarrhea and systemic infection. We previously established human intestinal enteroids as a model system to studyE.coli-host interactions. We report the first large-scale assessment of the host response to infection from all four segments of the intestine across different donor lines for five different pathotypes. Whereas the host response in the duodenum is driven by the infecting pathotype, the response in the colon diverges by donor. We observed a major upregulation of host mucins, particularly for EAEC, which led to the identification of heparan sulfate proteoglycans (HSPGs) as the receptor on human colonoids. Our research highlights a new role for HSPGs for EAEC infection.