Leslie Sheu

Membrane proteomics of phagosomes suggests a connection to autophagy

Phagocytosis is the central process by which macrophage cells internalize and eliminate infectious microbes as well as apoptotic cells. During maturation, phagosomes containing engulfed particles fuse with various endosomal compartments through the action of regulatory molecules on the phagosomal membrane. In this study, we performed a proteomic analysis of the membrane fraction from latex bead-containing (LBC) phagosomes isolated from macrophages. The profile, which comprised 546 proteins, suggests diverse functions of the phagosome and potential connections to secretory processes, toll-like receptor signaling, and autophagy. Many identified proteins were not previously known to reside in the phagosome. We characterized several proteins in LBC phagosomes that change in abundance on induction of autophagy, a process that has been previously implicated in the host defense against microbial pathogens. These observations suggest crosstalk between autophagy and phagocytosis that may be relevant to the innate immune response of macrophages.

Quantitative Proteomic Profiling of Host−Pathogen Interactions: The Macrophage Response to Mycobacterium tuberculosis Lipids

Mycobacterium tuberculosis (M. tuberculosis) is an intracellular pathogen possessing a complex mixture of cell wall lipids that are thought to modulate the activities of host macrophages. In this study, we employed two state-of-the-art quantitative proteomic approaches, metabolic labeling SILAC and chemical isobaric tagging iTRAQ, to study changes in macrophage protein expression in response to exposure to M. tuberculosis lipids. From a total of 1286 proteins identified, 463 were discovered by both isotope-labeling strategies at a high consistency, and the rest of proteins were detected by only one of the two approaches. Upon exposure to mycobacterial cell wall lipids, 166 macrophage proteins showed differential expression. These included proteins involved in the immune response, oxidation and reduction, and vesicle transport, as well as other cellular processes. The response of the macrophage proteome to M. tuberculosis lipids reflects the cells innate defense mechanisms as well as lipid-induced processes that may benefit the pathogen.

Organelle Membrane Proteomics Reveals Differential Influence of Mycobacterial Lipoglycans on Macrophage Phagosome Maturation and Autophagosome Accumulation

The mycobacterial cell wall component lipoarabinomannan (LAM) has been described as one of the key virulence factors of Mycobacterium tuberculosis. Modification of the terminal arabinan residues of this lipoglycan with mannose caps in M. tuberculosis or with phosphoinositol caps in Mycobacterium smegmatis results in distinct host immune responses. Given that M. tuberculosis typically persists in the phagosomal vacuole after being phagocytosed by macrophages, we performed a proteomic analysis of that organelle after treatment of macrophages with LAMs purified from the two mycobacterial species. The quantitative changes in phagosomal proteins suggested a distinct role for mannose-capped LAM in modulating protein trafficking pathways that contribute to the arrest of phagosome maturation. Enlightened by our proteomic data, we performed further experiments to show that only the LAM from M. tuberculosis inhibits accumulation of autophagic vacuoles in the macrophage, suggesting a new function for this virulence-associated lipid.

Learning Through Service: Student Perceptions on Volunteering at Interprofessional Hepatitis B Student-run Clinics

Student-run clinics (SRCs) are widespread, but studies on their educational impact are limited. We surveyed preclinical medical, nursing, and pharmacy students about their experiences in a hepatitis B elective which provided opportunities to they could volunteer at hepatitis B screening and vaccination SRCs. Student responses revealed positive perceptions of the volunteer experience. Benefits included interacting with patients, developing clinical skills, providing service to disadvantaged populations, and collaborating with health professional peers. Students who participated in clinic reported enhanced skills compared to those who did not attend. SRCs play a valuable role in instilling positive attitudes and improving skills.

Legitimate workplace roles and activities for early learners.

Given the calls for earlier student engagement in clinical experiences, educators are challenged to define roles for pre‐clerkship students that enable legitimate participation in clinical practice. This study aimed to determine the student roles and activities, as well as the clinic characteristics, that allow early student engagement within a specific clinical experience.

Systems-Based Practice Learning Opportunities in Student-Run Clinics: A Qualitative Analysis of Student Experiences

Purpose Student-run clinics (SRCs) provide preclerkship medical students with systems-based practice (SBP) experiences as they engage in patient care and manage clinic operations. This study explored the types and context of SBP activities students participate in at SRCs. Method Between November 2011 and February 2012, the authors conducted in-depth, semistructured interviews with a purposive sample of medical students who served as volunteers and coordinators (student leadership role) at four independently run SRCs within the University of California, San Francisco, School of Medicine. They also interviewed SRC faculty advisors. Interviews focused on student roles in SRCs, SBP learning opportunities in SRCs, and comparisons of SBP experiences in SRCs with those in the formal preclerkship curriculum. The authors used thematic analysis techniques to code and synthesize data. Results Data from interviews with 8 volunteers, 14 coordinators, and 4 faculty suggested six major domains related to SBP learning opportunities in SRCs: interprofessional roles and collaboration; clinic organization; patient factors affecting access to care; awareness of the larger health care system and continuity of care; resource acquisition and allocation; and systems improvement. Coordinators, who managed SRCs, demonstrated greater depth of SBP understanding than volunteers, who provided patient care. Students and faculty agreed that SRCs provided students with SBP learning opportunities beyond those available in the formal curriculum. Conclusions Preclerkship students’ participation in SRCs provides opportunities for in-depth learning of SBP, particularly among students who take on leadership roles. SRCs may model ways to effectively introduce key components of SBP to early medical learners.

A model for interprofessional health disparities education: student-led curriculum on chronic hepatitis B infection.

BACKGROUNDAlthough health disparities are commonly addressed in preclinical didactic curricula, direct patient care activities with affected communities are more limited.PURPOSETo address this problem, health professional students designed a preclinical service-learning curriculum on hepatitis B viral (HBV) infection, a major health disparity affecting the Asian/Pacific Islander (API) population, integrating lectures, skills training, and direct patient care at student-run clinics.SETTINGAn urban health professions campus.METHODSMedical and other health professional students at University of California, San Francisco, organized a preclinical didactic and experiential elective, and established two monthly clinics offering HBV screening, vaccination, and education to the community.RESULTSBetween 2004 and 2009, 477 students enrolled in the student-led HBV curriculum. Since the clinics’ inception in 2007, 804 patients have been screened for chronic HBV; 87% were API immigrants, 63% had limited English proficiency, and 46% were uninsured. Serologically, 10% were found to be chronic HBV carriers, 44% were susceptible to HBV, and 46% were immune.DISCUSSIONOur student-led didactic and experiential elective can serve as an interprofessional curricular model for learning about specific health disparities while providing important services to the local community.

We need to talk: Primary care provider communication at discharge in the era of a shared electronic medical record.

BACKGROUND Poor communication between hospitalists and outpatient physicians can contribute to adverse events after discharge. Electronic medical records (EMRs) shared by inpatient and outpatient clinicians offer primary care providers (PCPs) better access to information surrounding a patients hospitalization. However, the PCP experience and subsequent expectations for discharge communication within a shared EMR are unknown. METHODS We surveyed PCPs 1 year after a shared EMR was implemented at our institution to assess PCP satisfaction with current discharge communication practices and identify areas for improvement. RESULTS Seventy-five of 124 (60%) clinicians completed the survey. Although most PCPs reported receiving automated discharge notifications (71%), only 39% felt that notifications plus discharge summaries were adequate for safe transitions of care. PCPs expressed that complex hospitalizations necessitated additional communication via e-mail or telephone; only 31% reported receiving such communication. The content most important in additional communication included medication changes, follow-up actions, and active medical issues. CONCLUSIONS Despite optimized access to information provided by a shared EMR, only 52% of PCPs were satisfied with current discharge communication. PCPs express a continued need for high-touch communication for safe transitions of care. Further standardization of discharge communication practices is necessary.

Impact of Student-Run Clinics on Preclinical Sociocultural and Interprofessional Attitudes: A Prospective Cohort Analysis

Introduction. Descriptive studies suggest student-run clinics (SRCs) positively affect preclinical students’ sociocultural and interprofessional attitudes, but few studies use validated measures. Methods. In a pre-post design, first-year medical, nursing, and pharmacy students who did and did not participate in SRCs completed demographic and open-ended questions, as well as two validated surveys, the Sociocultural Attitudes in Medicine Inventory (SAMI) and Readiness for Interprofessional Learning Scale (RIPLS), at the beginning and end of the year. Results. With 68% (n=182/267) matched surveys we found no significant differences between groups over time (SAMI p=.53, RIPLS p≥.28 for each subcategory). However, of SRC participants, 99% reported commitment to the underserved and 57% reported improved interprofessional attitudes. Discussion. Students participating in SRCs perceive positive benefits, but do not score differently from those who do not. The SRC experiences may not be frequent enough to affect these measures, particularly since our students were high-scoring upon entry.

How Supervisor Experience Influences Trust, Supervision, and Trainee Learning: A Qualitative Study

Purpose Appropriate trust and supervision facilitate trainees’ growth toward unsupervised practice. The authors investigated how supervisor experience influences trust, supervision, and subsequently trainee learning. Method In a two-phase qualitative inductive content analysis, phase one entailed reviewing 44 internal medicine resident and attending supervisor interviews from two institutions (July 2013 to September 2014) for themes on how supervisor experience influences trust and supervision. Three supervisor exemplars (early, developing, experienced) were developed and shared in phase two focus groups at a single institution, wherein 23 trainees validated the exemplars and discussed how each impacted learning (November 2015). Results Phase one: Four domains of trust and supervision varying with experience emerged: data, approach, perspective, clinical. Early supervisors were detail oriented and determined trust depending on task completion (data), were rule based (approach), drew on their experiences as trainees to guide supervision (perspective), and felt less confident clinically compared with more experienced supervisors (clinical). Experienced supervisors determined trust holistically (data), checked key aspects of patient care selectively and covertly (approach), reflected on individual experiences supervising (perspective), and felt comfortable managing clinical problems and gauging trainee abilities (clinical). Phase two: Trainees felt the exemplars reflected their experiences, described their preferences and learning needs shifting over time, and emphasized the importance of supervisor flexibility to match their learning needs. Conclusions With experience, supervisors differ in their approach to trust and supervision. Supervisors need to trust themselves before being able to trust others. Trainees perceive these differences and seek supervision approaches that align with their learning needs.