The Ubiquitin-Interacting Motifs Target the Endocytic Adaptor Protein Epsin for Ubiquitination

The covalent attachment of ubiquitin to proteins is an evolutionarily conserved signal for rapid protein degradation. However, additional cellular functions for ubiquitination are now emerging, including regulation of protein trafficking and endocytosis [1]. For example, recent genetic studies suggested a role for ubiquitination in regulating epsin, a modular endocytic adaptor protein that functions in the assembly of clathrin-coated vesicles [2, 3]; however, biochemical evidence for this notion has been lacking. Epsin consists of an epsin NH2-terminal homology (ENTH) domain that promotes the interaction with phospholipids [4], several AP2 binding sites [5], two clathrin binding sequences [6], and several Eps15 homology (EH) domain binding motifs [3]. Interestingly, epsin also possesses several recently described ubiquitin-interacting motifs (UIMs) that have been postulated to bind ubiquitin [7]. Here, we demonstrate that epsin is predominantly monoubiquitinated and resistant to proteasomal degradation. The UIMs are necessary for epsin ubiquitination but are not the site of ubiquitination. Finally, we demonstrate that the isolated UIMs from both epsin and an unrelated monoubiquitinated protein, Eps15 [8], are sufficient to promote ubiquitination of a chimeric glutathione-S-transferase (GST)-UIM fusion protein. Thus, our data suggest that UIMs may serve as a general signal for ubiquitination

ME250 Project Redesign

Final report and team photo for Project 06 of ME450, Winter 2009 semester.The purpose of this project is to redesign the sophomore level mechanical engineering course and design project to allow students to utilize their classroom knowledge and creativity to manufacture a prototype. The team worked with Professor John Hart to establish a team project that incorporates various design and manufacturing methods, offers more creativity, and utilizes various materials and moving mechanical components. The team created two prototypes, equipment for the end of semester contest, and relevant lecture materials. This project will affect the future Mechanical Engineering (ME) design and manufacturing curriculum, and positively impact over 250 ME students each year.John Hart (Mechanical Engineering, U of M)http://deepblue.lib.umich.edu/bitstream/2027.42/62175/2/ME450 Winter2009 Team Photo - Project 06 - ME250 Project Redesign.jpghttp://deepblue.lib.umich.edu/bitstream/2027.42/62175/1/ME450 Winter2009 Final Report - Project 06 - ME250 Project Redesign.pd

Superior reductions in hepatic steatosis and fibrosis with co-administration of a glucagon-like peptide-1 receptor agonist and obeticholic acid in mice

Objective: Nonalcoholic steatohepatitis (NASH) is an unmet need associated with metabolic syndrome. There are no approved therapies for NASH; however, glucagon-like peptide-1 receptor (GLP-1R) and farnesoid-X receptor (FXR) agonists are promising drug targets. We investigated the therapeutic effects of co-administration of a GLP-1R agonist, IP118, with FXR agonist obeticholic acid (OCA) in mice. Methods: OCA and IP118 alone and in combination were sub-chronically administered to Lepob/Lepob mice with diet-induced NASH or diet-induced obese (DIO) mice. Metabolic (body weight and glucose) and liver (biochemical and histological) endpoints were assessed. NASH severity in Lepob/Lepob mice was graded using a customized integrated scoring system. Results: OCA reduced liver weight and lipid in NASH mice (both by −17%) but had no effect on plasma ALT or AST levels. In contrast, IP118 significantly reduced liver weight (−21%), liver lipid (−15%), ALT (−29%), and AST (−27%). The combination of OCA + IP118 further reduced liver weight (−29%), liver lipid (−22%), ALT (−39%), and AST (−36%). Combination therapy was superior to monotherapies in reducing hepatic steatosis, inflammation, and fibrosis. Hepatic improvements with IP118 and OCA + IP118 were associated with reduced body weight (−4.3% and −3.5% respectively) and improved glycemic control in OCA + IP118-treated mice. In DIO mice, OCA + IP118 co-administration reduced body weight (−25.3%) to a greater degree than IP118 alone (−12.5%) and further improved glucose tolerance and reduced hepatic lipid. Conclusion: Our data suggest a complementary or synergistic therapeutic effect of GLP-1R and FXR agonism in mouse models of metabolic disease and NASH

Simulating for Quality: A Centralized Quality Improvement and Patient Safety Simulation Curriculum for Residents and Fellows.

PROBLEM: Requirements for experiential education in quality improvement and patient safety (QI/PS) in graduate medical education (GME) have recently expanded. Major challenges to meeting these requirements include a lack of faculty with the needed expertise, paucity of standardized curricular models allowing for skill demonstration, and inconsistent access to data for iterative improvement. APPROACH: In October 2017, the authors began development of a centralized QI/PS flipped-classroom simulation-based medical education (SBME) curriculum for GME trainees across multiple disciplines at Oregon Health & Science University (OHSU). The curriculum development team included OHSU and Veterans Affairs faculty with experience in QI/PS and SBME, as well as house officers. The curriculum consisted of a pre-assessment and pre-work readings and videos (sent 3 weeks before the simulation day) and an 8-hour simulation day, with introductory activities, 4 linked simulation sessions, and concluding activities. The 4 linked simulation sessions followed the same medical error from disclosure and reporting to root cause analysis, iterative implementation of an action plan, and consolidation of lessons learned into routine operations with Lean huddles. OUTCOMES: In academic year 2018-2019, 71 residents and fellows of various postgraduate years from 23 training programs enrolled in 2 pilot sessions. Learners reacted favorably to the simulation curriculum. Learner attitudes, confidence, knowledge, and skills significantly increased across all QI/PS domains studied. NEXT STEPS: This approach focuses a small cadre of educators toward the creation of a centralized resource that, owing to its experiential SBME foundation, can accommodate many learners with data-driven practice-based learning and improvement cycles in a shorter timeframe than traditional QI initiatives. Next steps include the addition of a control group, assessment of the sustainability of learner outcomes, translation of learning to behavior change and improvements in patient and health system outcomes, and adapting the materials to include learners from different professions and levels

Adipocyte progenitor cells initiate monocyte chemoattractant protein-1-mediated macrophage accumulation in visceral adipose tissue

Objective: Macrophages are important producers of obesity-induced MCP-1; however, initial obesity-induced increases in MCP-1 production precede M1 macrophage accumulation in visceral adipose tissue (VAT). The initial cellular source of obesity-induced MCP-1 in vivo is currently unknown. Preliminary reports based on in vitro studies of preadipocyte cell lines and adherent stroma-vascular fraction cells suggest that resident stromal cells express MCP-1. In the past several years, elegant methods of identifying adipocyte progenitor cells (AdPCs) have become available, making it possible to study these cells in vivo. We have previously published that global deletion of transcription factor Inhibitor of Differentiation 3 (Id3) attenuates high fat diet-induced obesity, but it is unclear if Id3 plays a role in diet-induced MCP-1 production. We sought to determine the initial cellular source of MCP-1 and identify molecular regulators mediating MCP-1 production. Methods: Id3+/+ and Id3−/− mice were fed either a standard chow or HFD for varying lengths of time. Flow cytometry, semi-quantitative real-time PCR, ELISAs and adoptive transfers were used to assess the importance of AdPCs during diet-induced obesity. Flow cytometry was also performed on a cohort of 14 patients undergoing bariatric surgery. Results: Flow cytometry identified committed CD45−CD31−Ter119−CD29+CD34+Sca-1+CD24− adipocyte progenitor cells as producers of high levels of MCP-1 in VAT. High-fat diet increased AdPC numbers, an effect dependent on Id3. Loss of Id3 increased p21Cip1 levels and attenuated AdPC proliferation, resulting in reduced MCP-1 and M1 macrophage accumulation in VAT, compared to Id3+/+ littermate controls. AdPC rescue by adoptive transfer of 50,000 Id3+/+ AdPCs into Id3−/− recipient mice increased MCP-1 levels and M1 macrophage number in VAT. Additionally, flow cytometry identified MCP-1-producing CD45−CD31−CD34+CD44+CD90+ AdPCs in human omental and subcutaneous adipose tissue, with a higher percentage in omental adipose. Furthermore, high surface expression of CD44 marked abundant MCP-1 producers, only in visceral adipose tissue. Conclusions: This study provides the first in vivo evidence, to our knowledge, that committed AdPCs in VAT are the initial source of obesity-induced MCP-1 and identifies the helix-loop-helix transcription factor Id3 as a critical regulator of p21Cip1 expression, AdPC proliferation, MCP-1 expression and M1 macrophage accumulation in VAT. Inhibition of Id3 and AdPC expansion, as well as CD44 expression in human AdPCs, may serve as unique therapeutic targets for the regulation of adipose tissue inflammation