Depletion assisted hemin affinity (DAsHA) proteomics reveals an expanded landscape of heme-binding proteins in the human proteome.

Heme b (iron protoporphyrin IX) plays important roles in biology as a metallocofactor and signaling molecule. However, the targets of heme signaling and the network of proteins that mediate the exchange of heme from sites of synthesis or uptake to heme dependent or regulated proteins are poorly understood. Herein, we describe a quantitative mass spectrometry (MS)-based chemoproteomics strategy to identify exchange labile hemoproteins in human embryonic kidney HEK293 cells that may be relevant to heme signaling and trafficking. The strategy involves depleting endogenous heme with the heme biosynthetic inhibitor succinylacetone (SA), leaving putative heme-binding proteins in their apo-state, followed by the capture of those proteins using hemin-agarose resin, and finally elution and identification by MS. By identifying only those proteins that interact with high specificity to hemin-agarose relative to control beaded agarose in an SA-dependent manner, we have expanded the number of proteins and ontologies that may be involved in binding and buffering labile heme or are targets of heme signaling. Notably, these include proteins involved in chromatin remodeling, DNA damage response, RNA splicing, cytoskeletal organization, and vesicular trafficking, many of which have been associated with heme through complementary studies published recently. Taken together, these results provide support for the emerging role of heme in an expanded set of cellular processes from genome integrity to protein trafficking and beyond.

A patient- and parent-centered approach to urinary and fecal incontinence in children and adolescents with spina bifida: understanding experiences in the context of other competing care issues.

INTRODUCTION: Despite significant and known challenges to urinary and fecal incontinence (UI and FI, respectively) among children with spina bifida (SB) and their families, few studies have identified patient-centered measures and approaches to assessing them. This study represents the first stage of a larger study to develop a patient-centered goal-setting tool to guide incontinence management (Figure). Our aim was to understand patient experiences of UI and FI, and what goals should be included in the tool. METHODS: We used a qualitative research approach integrated with human-centered design methods. We recruited, in clinic and online, children with SB (8-17 years old) and parents (>=18 years old) of children with SB (8-17 years old). Online activities were analyzed by four experienced design researchers using affinity diagramming, group analysis and modeling activities (mind maps, challenge maps, experience maps). Recruitment and thematic qualitative analysis continued until saturation was reached. RESULTS: Seventeen children with SB participated (9 female, 12 shunted, 13 using bladder catheterizations, 6 using Malone antegrade continence enema, median age: 15 years old). Fifteen parents participated (13 mothers/2 fathers, median age: 42 years old), including six mother-child dyads. Five major themes each were identified for UI and FI experiences: (1) negative emotional impact of incontinence, (2) unpredictability of incontinence, (3) challenging/unpleasant incontinence management, (4) inconvenient/unreliable incontinence management, (5) UI management having unpleasant complications and FI putting much responsibility on parents. We identified six UI goal domains and five FI goal domains. Four overlapping domains included: accidents, independence, interruptions at school and social/friends. Unique domains were: urinary tract infections (UI), catheterizations (UI) and enemas (FI). COMMENT: Findings of our study improve our understanding of children's and parents' experiences associated with incontinence in SB and potential continence goals. CONCLUSIONS: Children with SB experience incontinence as distressing and unpredictable. Incontinence management can be challenging and unreliable. Patient-centered continence goals cluster in domains, indicating how incontinence intermeshes with other life areas and offering potential approaches to structure continence goals in a goals-selection tool.