GRP75 as a functional element of cholix transcytosis.

Cholix (Chx) is secreted by non-pandemic strains of Vibrio cholerae in the intestinal lumen. For this exotoxin to induce cell death in non-polarized cells in the intestinal lamina propria, it must traverse the epithelium in the fully intact form. We identified host cell elements in polarized enterocytes associated with Chx endocytosis and apical to basal (A→B) vesicular transcytosis. This pathway overcomes endogenous mechanisms of apical vesicle recycling and lysosomal targeting by interacting with several host cell proteins that include the 75 kDa glucose-regulated protein (GRP75). Apical endocytosis of Chx appears to involve the single membrane spanning protein TMEM132A, and interaction with furin before it engages GRP75 in apical vesicular structures. Sorting within these apical vesicles results in Chx being trafficked to the basal region of cells in association with the Lectin, Mannose Binding 1 protein LMAN1. In this location, Chx interacts with the basement membrane-specific heparan sulfate proteoglycan perlecan in recycling endosomes prior to its release from this basal vesicular compartment to enter the underlying lamina propria. While the furin and LMAN1 elements of this Chx transcytosis pathway undergo cellular redistribution that are reflective of the polarity shifts noted for coatamer complexes COPI and COPII, GRP75 and perlecan fail to show these dramatic rearrangements. Together, these data define essential steps in the A→B transcytosis pathway accessed by Chx to reach the intestinal lamina propria where it can engage and intoxicate certain non-polarized cells.

The Vibrio cholerae exotoxin protein cholix interacts with a number of host cell proteins, including GRP75, to facilitate its vesicular transcytosis across polarized intestinal epithelial cells following apical endocytosis.

Training Residents in Advance Care Planning: A Task-Based Needs Assessment Using the 4-Component Instructional Design.

BACKGROUND: Residents may learn how to perform advance care planning (ACP) through informal curriculum. Task-based instructional designs and recent international consensus statements for ACP provide opportunities to explicitly train residents, but residents' needs are poorly understood. OBJECTIVE: We assessed residents' training needs in ACP at the Geneva University Hospitals in Geneva, Switzerland. METHODS: Qualitative data were collected and analyzed iteratively between December 2017 and September 2019. Transcripts were coded using both a deductive content analysis based on the 4-Component Instructional Design (4C/ID) model and an inductive thematic analysis. RESULTS: Out of 55 individuals contacted by email, 49 (89%) participated in 7 focus groups and 10 individual interviews, including 19 residents, 18 fellows and attending physicians, 4 nurses, 1 psychologist, 1 medical ethics consultant, 3 researchers, and 3 patients. Participants identified 3 tasks expected of residents (preparing, discussing, and documenting ACP) and discussed why training residents in ACP is complex. Participants described knowledge (eg, prognosis), skills (eg, clinical and ethical reasoning), and attitudes (eg, reflexivity) that residents need to become competent in ACP and identified needs for future training. In terms of the 4C/ID, these needs revolved around: (1) learning tasks (eg, workplace practice, simulated scenarios); (2) supportive information (eg, videotaped worked examples, cognitive feedback); (3) procedural information (eg, ACP pocket-sized information sheet, corrective feedback); and (4) part-task practice (eg, rehearsal of communication skills, simulation). CONCLUSIONS: This study provides a comprehensive description of tasks and competencies to train residents in ACP.