Sclerostin, Osteocytes, and Wnt Signaling in Pediatric Renal Osteodystrophy.

The pathophysiology of chronic kidney disease-mineral and bone disorder (CKD-MBD) is not well understood. Specific factors secreted by osteocytes are elevated in the serum of adults and pediatric patients with CKD-MBD, including FGF-23 and sclerostin, a known inhibitor of the Wnt signaling pathway. The molecular mechanisms that promote bone disease during the progression of CKD are incompletely understood. In this study, we performed a cross-sectional analysis of 87 pediatric patients with pre-dialysis CKD and post-dialysis (CKD 5D). We assessed the associations between serum and bone sclerostin levels and biomarkers of bone turnover and bone histomorphometry. We report that serum sclerostin levels were elevated in both early and late CKD. Higher circulating and bone sclerostin levels were associated with histomorphometric parameters of bone turnover and mineralization. Immunofluorescence analyses of bone biopsies evaluated osteocyte staining of antibodies towards the canonical Wnt target, ß-catenin, in the phosphorylated (inhibited) or unphosphorylated (active) forms. Bone sclerostin was found to be colocalized with phosphorylated ß-catenin, which suggests that Wnt signaling was inhibited. In patients with low serum sclerostin levels, increased unphosphorylated "active" ß-catenin staining was observed in osteocytes. These data provide new mechanistic insight into the pathogenesis of CKD-MBD and suggest that sclerostin may offer a potential biomarker or therapeutic target in pediatric renal osteodystrophy.

Vitamin B6 is governed by the local compartmentalization of metabolic enzymes during growth.

Vitamin B6 is a vital micronutrient across cell types and tissues, and dysregulated B6 levels contribute to human disease. Despite its importance, how B6 vitamer levels are regulated is not well understood. Here, we provide evidence that B6 dynamics are rapidly tuned by precise compartmentation of pyridoxal kinase (PDXK), the rate-limiting B6 enzyme. We show that canonical Wnt rapidly led to the accumulation of inactive B6 by shunting cytosolic PDXK into lysosomes. PDXK was modified with methyl-arginine Degron (MrDegron), a protein tag for lysosomes, which enabled delivery via microautophagy. Hyperactive lysosomes resulted in the continuous degradation of PDXK and B6 deficiency that promoted proliferation in Wnt-driven colorectal cancer (CRC) cells. Pharmacological or genetic disruption of the coordinated MrDegron proteolytic pathway was sufficient to reduce CRC survival in cells and organoid models. In sum, this work contributes to the repertoire of micronutrient-regulated processes that enable cancer cell growth and provides insight into the functional impact of B6 deficiencies for survival.

All the might of the osteocyte: emerging roles in chronic kidney disease.

Osteocytes are the most abundant type of bone cell and play crucial roles in bone health. Osteocytes sense mechanical stress and orchestrate osteoblasts and osteoclasts to maintain bone density and strength. Beyond this, osteocytes have also emerged as key regulators of organ crosstalk, and they function as endocrine organs via their roles in secreting factors that mediate signaling within their neighboring bone cells and in distant tissues. As such, osteocyte dysfunction has been associated with the bone abnormalities seen across a spectrum of chronic kidney disease. Specifically, dysregulated osteocyte morphology and signaling have been observed in the earliest stages of chronic kidney disease and have been suggested to contribute to kidney disease progression. More important, US Food and Drug Administration-approved inhibitors of osteocytic secreted proteins, such as fibroblast growth factor 23 and sclerostin, have been used to treat bone diseases. The present mini review highlights new research that links dysfunctional osteocytes to the pathogenesis of chronic kidney disease mineral and bone disorder.

Hitting the Sweet Spot: How Glucose Metabolism Is Orchestrated in Space and Time by Phosphofructokinase-1.

Glycolysis is the central metabolic pathway across all kingdoms of life. Intensive research efforts have been devoted to understanding the tightly orchestrated processes of converting glucose into energy in health and disease. Our review highlights the advances in knowledge of how metabolic and gene networks are integrated through the precise spatiotemporal compartmentalization of rate-limiting enzymes. We provide an overview of technically innovative approaches that have been applied to study phosphofructokinase-1 (PFK1), which represents the fate-determining step of oxidative glucose metabolism. Specifically, we discuss fast-acting chemical biology and optogenetic tools that have delineated new links between metabolite fluxes and transcriptional reprogramming, which operate together to enact tissue-specific processes. Finally, we discuss how recent paradigm-shifting insights into the fundamental basis of glycolytic regulatory control have shed light on the mechanisms of tumorigenesis and could provide insight into new therapeutic vulnerabilities in cancer.

Simplifying the B Complex: How Vitamins B6 and B9 Modulate One Carbon Metabolism in Cancer and Beyond.

Vitamin B micronutrients are essential regulators of one carbon metabolism that ensures human health. Vitamin B9, or folate, lies at the heart of the folate cycle and converges with the methionine cycle to complete the one carbon pathway. Additionally, vitamin B6 contributes by orchestrating the flux of one carbon cycling. Dysregulation of vitamin B contributes to altered biochemical signaling that manifests in a spectrum of human diseases. This review presents an analysis of the past, present, and future work, highlighting the interplay between folate and vitamin B6 in one carbon metabolism. Emerging insights include advances in metabolomic-based mass spectrometry and the use of live-cell metabolic labeling. Cancer is used as a focal point to dissect vitamin crosstalk and highlight new insights into the roles of folate and vitamin B6 in metabolic control. This collection of vitamin-based research detailing the trends of one carbon metabolism in human disease exemplifies how the future of personalized medicine could unfold using this new base of knowledge and ultimately provide next-generation therapeutics.

Metabolism and Endocrine Disorders: What Wnt Wrong?

A fundamental question in cell biology underlies how nutrients are regenerated to maintain and renew tissues. Physiologically, the canonical Wnt signaling is a vital pathway for cell growth, tissue remodeling, and organ formation; pathologically, Wnt signaling contributes to the development of myriad human diseases such as cancer. Despite being the focus of intense research, how Wnt intersects with the metabolic networks to promote tissue growth and remodeling has remained mysterious. Our understanding of metabolism has been revolutionized by technological advances in the fields of chemical biology, metabolomics, and live microscopy that have now made it possible to visualize and manipulate metabolism in living cells and tissues. The application of these toolsets to innovative model systems have propelled the Wnt field into new realms at the forefront answering the most pressing paradigms of cell metabolism in health and disease states. Elucidating the basis of Wnt signaling and metabolism in a cell-type and tissue-specific manner will provide a powerful base of knowledge for both basic biomedical fields and clinician scientists, and has the promise to generate new, transformative therapies in disease and even processes of aging.

Cell Biology of Canonical Wnt Signaling.

Wnt signaling has multiple functions beyond the transcriptional effects of ß-catenin stabilization. We review recent investigations that uncover new cell physiological effects through the regulation of Wnt receptor endocytosis, Wnt-induced stabilization of proteins (Wnt-STOP), macropinocytosis, increase in lysosomal activity, and metabolic changes. Many of these growth-promoting effects of canonical Wnt occur within minutes and are independent of new protein synthesis. A key element is the sequestration of glycogen synthase kinase 3 (GSK3) inside multivesicular bodies and lysosomes. Twenty percent of human proteins contain consecutive GSK3 phosphorylation motifs, which in the absence of Wnt can form phosphodegrons for polyubiquitination and proteasomal degradation. Wnt signaling by either the pharmacological inhibition of GSK3 or the loss of tumor-suppressor proteins, such as adenomatous polyposis coli (APC) and Axin1, increases lysosomal acidification, anabolic metabolites, and macropinocytosis, which is normally repressed by the GSK3-Axin1-APC destruction complex. The combination of these cell physiological effects drives cell growth.

Characterization of Primary Cilia in Osteoblasts Isolated From Patients With ADPKD and CKD.

Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited cause of chronic kidney disease (CKD) and leads to a specific type of bone disease. The primary cilium is a major cellular organelle implicated in the pathophysiology of ADPKD caused by mutations in polycystin-1 (PKD1) and polycystin-2 (PKD2). In this study, for the first time, cilia were characterized in primary preosteoblasts isolated from patients with ADPKD. All patients with ADPKD had low bone turnover and primary osteoblasts were also obtained from patients with non-ADPKD CKD with low bone turnover. Image-based immunofluorescence assays analyzed cilia using standard markers, pericentrin, and acetylated-α-tubulin, where cilia induction and elongation were chosen as relevant endpoints for these initial investigations. Osteoblastic activity was examined by measuring alkaline phosphatase levels and mineralized matrix deposition rates. It was found that primary cilia can be visualized in patient-derived osteoblasts and respond to elongation treatments. Compared with control cells, ADPKD osteoblasts displayed abnormal cilia elongation that was significantly more responsive in cells with PKD2 nontruncating mutations and PKD1 mutations. In contrast, non-ADPKD CKD osteoblasts were unresponsive and had shorter cilia. Finally, ADPKD osteoblasts showed increased rates of mineralized matrix deposition compared with non-ADPKD CKD. This work represents the first study of cilia in primary human-derived osteoblasts from patients with CKD and patients with ADPKD who have normal kidney function, offering new insights as bone disease phenotypes are not well recapitulated in animal models. These data support a model whereby altered cilia occurs in PKD-mutated osteoblasts, and that ADPKD-related defects in bone cell activity and mineralization are distinct from adynamic bone disease from patients with non-ADPKD CKD. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.

Wnt-inducible Lrp6-APEX2 interacting proteins identify ESCRT machinery and Trk-fused gene as components of the Wnt signaling pathway.

The canonical Wnt pathway serves as a hub connecting diverse cellular processes, including ß-catenin signaling, differentiation, growth, protein stability, macropinocytosis, and nutrient acquisition in lysosomes. We have proposed that sequestration of ß-catenin destruction complex components in multivesicular bodies (MVBs) is required for sustained canonical Wnt signaling. In this study, we investigated the events that follow activation of the canonical Wnt receptor Lrp6 using an APEX2-mediated proximity labeling approach. The Wnt co-receptor Lrp6 was fused to APEX2 and used to biotinylate targets that are recruited near the receptor during Wnt signaling at different time periods. Lrp6 proximity targets were identified by mass spectrometry, and revealed that many endosomal proteins interacted with Lrp6 within 5 min of Wnt3a treatment. Interestingly, we found that Trk-fused gene (TFG), previously known to regulate the cell secretory pathway and to be rearranged in thyroid and lung cancers, was strongly enriched in the proximity of Lrp6. TFG depletion with siRNA, or knock-out with CRISPR/Cas9, significantly reduced Wnt/ß-catenin signaling in cell culture. In vivo, studies in the Xenopus system showed that TFG is required for endogenous Wnt-dependent embryonic patterning. The results suggest that the multivesicular endosomal machinery and the novel player TFG have important roles in Wnt signaling.

GSK3 Inhibits Macropinocytosis and Lysosomal Activity through the Wnt Destruction Complex Machinery.

Canonical Wnt signaling is emerging as a major regulator of endocytosis. Here, we report that Wnt-induced macropinocytosis is regulated through glycogen synthase kinase 3 (GSK3) and the ß-catenin destruction complex. We find that mutation of Axin1, a tumor suppressor and component of the destruction complex, results in the activation of macropinocytosis. Surprisingly, inhibition of GSK3 by lithium chloride (LiCl), CHIR99021, or dominant-negative GSK3 triggers macropinocytosis. GSK3 inhibition causes a rapid increase in acidic endolysosomes that is independent of new protein synthesis. GSK3 inhibition or Axin1 mutation increases lysosomal activity, which can be followed with tracers of active cathepsin D, ß-glucosidase, and ovalbumin degradation. Microinjection of LiCl into the blastula cavity of Xenopus embryos causes a striking increase in dextran macropinocytosis. The effects of GSK3 inhibition on protein degradation in endolysosomes are blocked by the macropinocytosis inhibitors EIPA or IPA-3, suggesting that increases in membrane trafficking drive lysosomal activity.

Wnt canonical pathway activates macropinocytosis and lysosomal degradation of extracellular proteins.

Canonical Wnt signaling is emerging as a major regulator of endocytosis. Wnt treatment markedly increased the endocytosis and degradation in lysosomes of BSA. In this study, we report that in addition to receptor-mediated endocytosis, Wnt also triggers the intake of large amounts of extracellular fluid by macropinocytosis, a nonreceptor-mediated actin-driven process. Macropinocytosis induction is rapid and independent of protein synthesis. In the presence of Wnt, large amounts of nutrient-rich packages such as proteins and glycoproteins were channeled into lysosomes after fusing with smaller receptor-mediated vesicles containing glycogen synthase kinase 3 (GSK3) and protein arginine ethyltransferase 1 (PRMT1), an enzyme required for canonical Wnt signaling. Addition of Wnt3a, as well as overexpression of Disheveled (Dvl), Frizzled (Fz8), or dominant-negative Axin induced endocytosis. Depletion of the tumor suppressors adenomatous polyposis coli (APC) or Axin dramatically increased macropinocytosis, defined by incorporation of the high molecular weight marker tetramethylrhodamine (TMR)-dextran and its blockage by the Na+/H+ exchanger ethylisopropyl amiloride (EIPA). Macropinocytosis was blocked by dominant-negative vacuolar protein sorting 4 (Vps4), indicating that the Wnt pathway is dependent on multivesicular body formation, a process called microautophagy. SW480 colorectal cancer cells displayed constitutive macropinocytosis and increased extracellular protein degradation in lysosomes, which were suppressed by restoring full-length APC. Accumulation of the transcriptional activator ß-catenin in the nucleus of SW480 cells was inhibited by methyltransferase inhibition, EIPA, or the diuretic amiloride. The results indicate that Wnt signaling switches metabolism toward nutrient acquisition by engulfment of extracellular fluids and suggest possible treatments for Wnt-driven cancer progression.

Canonical Wnt is inhibited by targeting one-carbon metabolism through methotrexate or methionine deprivation.

The nutrient-sensing metabolite S-adenosylmethionine (SAM) controls one-carbon metabolism by donating methyl groups to biochemical building blocks, DNA, RNA, and protein. Our recent work uncovered a requirement for cytoplasmic arginine methylation during Wnt signaling through the activity of protein arginine methyltransferase 1 (PRMT1), which transfers one-carbon groups from SAM to many protein substrates. Here, we report that treatments that decrease levels of the universal methyl donor SAM were potent inhibitors of Wnt signaling and of Wnt-induced digestion of extracellular proteins in endolysosomes. Thus, arginine methylation provides the canonical Wnt pathway with metabolic sensing properties through SAM. The rapid accumulation of Wnt-induced endolysosomes within 30 minutes was inhibited by the depletion of methionine, an essential amino acid that serves as the direct substrate for SAM production. We also found that methionine is required for GSK3 sequestration into multivesicular bodies through microautophagy, an essential step in Wnt signaling activity. Methionine starvation greatly reduced Wnt-induced endolysosomal degradation of extracellular serum proteins. Similar results were observed by addition of nicotinamide (vitamin B3), which serves as a methyl group sink. Methotrexate, a pillar in the treatment of cancer since 1948, decreases SAM levels. We show here that methotrexate blocked Wnt-induced endocytic lysosomal activity and reduced canonical Wnt signaling. Importantly, the addition of SAM during methionine depletion or methotrexate treatment was sufficient to rescue endolysosomal function and Wnt signaling. Inhibiting the Wnt signaling pathway by decreasing one-carbon metabolism provides a platform for designing interventions in Wnt-driven disease.

Evaluating a knowledge translation tool for parents about pediatric acute gastroenteritis: a pilot randomized trial.

BACKGROUND: Pediatric acute gastroenteritis (AGE) is a common childhood illness with substantial health, family, and system impacts. Connecting parents to evidence-based patient education is key to effective decision-making and therapeutic management of AGE. Digital knowledge translation (KT) tools offer a promising approach to communicate complex health information to parents; therefore, we developed a whiteboard animation video for parents about AGE. To optimize future effectiveness evaluation of this video, the purpose of this pilot study is to assess feasibility of effectiveness outcomes and specific trial methods in four key trial domains. METHODS: A single-site, parallel-arm, pilot randomized trial will be conducted. The trial will employ quantitative and qualitative methods to evaluate feasibility objectives in key scientific, process, management, and resource domains. Parents seeking care for a child with AGE in the emergency department (ED) over a 6-month period will be randomized to receive the whiteboard animation video or a sham control video. Quantitative data will be collected electronically in the ED and at home (4-10 days post-ED visit). Qualitative data will be collected via semi-structured interviews with experimental condition participants after quantitative data collection. Data will be collected to perform a sample size calculation for a full-scale trial. Scientific outcomes will include parental knowledge, decision regret, and health utilization, and estimation for these outcomes will use confidence intervals (CI) of different widths to illustrate strength of preliminary evidence. CIs will be presented alongside minimum clinically important differences (MCIDs) calculated using two methods: (1) data driven and (2) patient perspective. Descriptive statistics will be calculated to describe process, management, and resource domain outcomes. Qualitative thematic analysis will be conducted to describe additional process, management, and resource outcomes in the experimental group. Analyses will be performed using intention-to-treat. DISCUSSION: This pilot randomized trial will inform the design and conduct of a full-scale, effectiveness trial by gathering key data in four domains: scientific, process, management, and resource. These results will impact the emerging field of KT efforts targeting health consumers and advance the science on the best mode of patient education for acute childhood illnesses. TRIAL REGISTRATION: clinicaltrails.gov registration number NCT03234777. Registered 31 July 2017.

Arginine methylation is required for canonical Wnt signaling and endolysosomal trafficking.

Arginine methylation has emerged as a widespread and reversible protein modification with the potential to regulate a multitude of cellular processes, but its function is poorly understood. Endolysosomes play an important role in Wnt signaling, in which glycogen synthase kinase 3 (GSK3) becomes sequestered inside multivesicular bodies (MVBs) by the process known as microautophagy, causing the stabilization of many proteins. Up to 20% of cellular proteins contain three or more consecutive putative GSK3 sites, and of these 33% also contain methylarginine (meArg) modifications. Intriguingly, a cytoskeletal protein was previously known to have meArg modifications that enhanced subsequent phosphorylations by GSK3. Here, we report the unexpected finding that protein arginine methyltransferase 1 (PRMT1) is required for canonical Wnt signaling. Treatment of cultured cells for 5-30 min with Wnt3a induced a large increase in total endocytic vesicles which were also positive for asymmetric dimethylarginine modifications. Protease protection studies, both biochemical and in situ in cultured cells, showed that many meArg-modified cytosolic proteins became rapidly translocated into MVBs together with GSK3 and Lys48-polyubiquitinated proteins by ESCRT-driven microautophagy. In the case of the transcription factor Smad4, we showed that a unique arginine methylation site was required for GSK3 phosphorylation and Wnt regulation. The enzyme PRMT1 was found to be essential for Wnt-stimulated arginine methylation, GSK3 sequestration, and canonical Wnt signaling. The results reveal a cell biological role for PRMT1 arginine methylation at the crossroads of growth factor signaling, protein phosphorylation, membrane trafficking, cytosolic proteolysis, and Wnt-regulated microautophagy.

Pediatric information seeking behaviour, information needs, and information preferences of health care professionals in general emergency departments: Results from the Translating Emergency Knowledge for Kids (TREKK) Needs Assessment.

The majority of children requiring emergency care are treated in general emergency departments (EDs) with variable levels of pediatric care expertise. The goal of the Translating Emergency Knowledge for Kids (TREKK) initiative is to implement the latest research in pediatric emergency medicine in general EDs to reduce clinical variation. OBJECTIVES: To determine national pediatric information needs, seeking behaviours, and preferences of health care professionals working in general EDs. METHODS: An electronic cross-sectional survey was conducted with health care professionals in 32 Canadian general EDs. Data were collected in the EDs using the iPad and in-person data collectors. RESULTS: Total of 1,471 surveys were completed (57.1% response rate). Health care professionals sought information on children's health care by talking to colleagues (n=1,208, 82.1%), visiting specific medical/health websites (n=994, 67.7%), and professional development opportunities (n=941, 64.4%). Preferred child health resources included protocols and accepted treatments for common conditions (n=969, 68%), clinical pathways and practice guidelines (n=951, 66%), and evidence-based information on new diagnoses and treatments (n=866, 61%). Additional pediatric clinical information is needed about multisystem trauma (n=693, 49%), severe head injury (n=615, 43%), and meningitis (n=559, 39%). Health care professionals preferred to receive child health information through professional development opportunities (n=1,131, 80%) and printed summaries (n=885, 63%). CONCLUSION: By understanding health care professionals' information seeking behaviour, information needs, and information preferences, knowledge synthesis and knowledge translation initiatives can be targeted to improve pediatric emergency care. The findings from this study will inform the following two phases of the TREKK initiative to bridge the research-practice gap in Canadian general EDs.

Usability and Acceptability of a Home Blood Pressure Telemonitoring Device Among Community-Dwelling Senior Citizens With Hypertension: Qualitative Study.

BACKGROUND: Hypertension is a major cause of cardiovascular disease in older individuals. To ensure that blood pressure (BP) levels are within the optimal range, accurate BP monitoring is required. Contemporary hypertension clinical practice guidelines strongly endorse the use of home BP measurement as a preferred method of BP monitoring for individuals with hypertension. The benefits of home BP monitoring may be optimized when measurements are telemonitored to care providers; however, this may be challenging for older individuals with less technological capabilities. OBJECTIVE: The objective of this qualitative study was to examine the usability and acceptability of a home BP telemonitoring device among senior citizens. METHODS: We conducted a qualitative descriptive study. Following a 1-week period of device use, individual, semistructured interviews were conducted. Interview audio recordings were anonymized, de-identified, and transcribed verbatim. We performed thematic analysis on interview transcripts. RESULTS: Seven senior citizens participated in the usability testing of the home BP telemonitoring device. Participants comprised females (n=4) and males (n=3) with a mean age of 86 years (range, 70-95 years). Overall, eight main themes were identified from the interviews: (1) positive features of the device; (2) difficulties or problems with the device; (3) device was simple to use; (4) comments about wireless capability and components; (5) would recommend device to someone else; (6) would use device in future; (7) suggestions for improving the device; and (8) assistance to use device. Additional subthemes were also identified. CONCLUSIONS: Overall, the home BP telemonitoring device had very good usability and acceptability among community-dwelling senior citizens with hypertension. To enhance its long-term use, few improvements were noted that may mitigate some of the relatively minor challenges encountered by the target population.

Classification schemes for knowledge translation interventions: a practical resource for researchers.

BACKGROUND: As implementation science advances, the number of interventions to promote the translation of evidence into healthcare, health systems, or health policy is growing. Accordingly, classification schemes for these knowledge translation (KT) interventions have emerged. A recent scoping review identified 51 classification schemes of KT interventions to integrate evidence into healthcare practice; however, the review did not evaluate the quality of the classification schemes or provide detailed information to assist researchers in selecting a scheme for their context and purpose. This study aimed to further examine and assess the quality of these classification schemes of KT interventions, and provide information to aid researchers when selecting a classification scheme. METHODS: We abstracted the following information from each of the original 51 classification scheme articles: authors' objectives; purpose of the scheme and field of application; socioecologic level (individual, organizational, community, system); adaptability (broad versus specific); target group (patients, providers, policy-makers), intent (policy, education, practice), and purpose (dissemination versus implementation). Two reviewers independently evaluated the methodological quality of the development of each classification scheme using an adapted version of the AGREE II tool. Based on these assessments, two independent reviewers reached consensus about whether to recommend each scheme for researcher use, or not. RESULTS: Of the 51 original classification schemes, we excluded seven that were not specific classification schemes, not accessible or duplicates. Of the remaining 44 classification schemes, nine were not recommended. Of the 35 recommended classification schemes, ten focused on behaviour change and six focused on population health. Many schemes (n = 29) addressed practice considerations. Fewer schemes addressed educational or policy objectives. Twenty-five classification schemes had broad applicability, six were specific, and four had elements of both. Twenty-three schemes targeted health providers, nine targeted both patients and providers and one targeted policy-makers. Most classification schemes were intended for implementation rather than dissemination. CONCLUSIONS: Thirty-five classification schemes of KT interventions were developed and reported with sufficient rigour to be recommended for use by researchers interested in KT in healthcare. Our additional categorization and quality analysis will aid in selecting suitable classification schemes for research initiatives in the field of implementation science.

Knowledge translation tools for parents on child health topics: a scoping review.

BACKGROUND: An emerging field of knowledge translation (KT) research has begun to focus on health consumers, particularly in child health. KT tools provide health consumers with research knowledge to inform health decision-making and may foster 'effective consumers'. Thus, the purpose of this scoping review was to describe the state of the field of previously published effectiveness research on child health-related KT tools for parents/caregivers to understand the evidence-base, identify gaps, and guide future research efforts. METHODS: A health research librarian developed and implemented search strategies in 8 databases. One reviewer conducted screening using pre-determined criteria. A second reviewer verified 10% of screening decisions. Data extraction was performed by one reviewer. A descriptive analysis was conducted and included patient-important outcome classification, WIDER Recommendation checklist, and methodological quality assessment. RESULTS: Seven thousand nine hundred fifty two independent titles and abstracts were reviewed, 2267 full-text studies were retrieved and reviewed, and 18 articles were included in the final data set. A variety of KT tools, including single- (n = 10) and multi-component tools (n = 10), were evaluated spanning acute (n = 4), chronic (n = 5) and public/population health (n = 9) child health topics. Study designs included: cross-sectional (n = 4), before-after (n = 1), controlled before-after (n = 2), cohort (n = 1), and RCTs (n = 10). The KT tools were evaluated via single primary outcome category (n = 11) and multiple primary outcome categories (n = 7). Two studies demonstrated significant positive effects on primary outcome categories; the remaining studies demonstrated mixed effects (n = 9) and no effect (n = 3). Overall, methodological quality was poor; studies lacked a priori protocols (n = 18) and sample size calculations (n = 13). Overall, intervention reporting was also poor; KT tools lacked description of theoretical underpinnings (n = 14), end-user engagement (n = 13), and preliminary research (n = 9) to inform the current effectiveness evaluation. CONCLUSIONS: A number of child health-related knowledge translation tools have been developed for parents/caregivers. However, numerous outcomes were used to assess impact and there is limited evidence demonstrating their effectiveness. Moreover, the methodological rigor and reporting of effectiveness studies is limited. Careful tool development involving end-users and preliminary research, including usability testing and mixed methods, prior to large-scale studies may be important to advance the science of KT for health consumers.

Epidermal Growth Factor Receptor neddylation is regulated by a desmosomal-COP9 (Constitutive Photomorphogenesis 9) signalosome complex.

Cell junctions are scaffolds that integrate mechanical and chemical signaling. We previously showed that a desmosomal cadherin promotes keratinocyte differentiation in an adhesion-independent manner by dampening Epidermal Growth Factor Receptor (EGFR) activity. Here we identify a potential mechanism by which desmosomes assist the de-neddylating COP9 signalosome (CSN) in attenuating EGFR through an association between the Cops3 subunit of the CSN and desmosomal components, Desmoglein1 (Dsg1) and Desmoplakin (Dp), to promote epidermal differentiation. Silencing CSN or desmosome components shifts the balance of EGFR modifications from ubiquitination to neddylation, inhibiting EGFR dynamics in response to an acute ligand stimulus. A reciprocal relationship between loss of Dsg1 and neddylated EGFR was observed in a carcinoma model, consistent with a role in sustaining EGFR activity during tumor progression. Identification of this previously unrecognized function of the CSN in regulating EGFR neddylation has broad-reaching implications for understanding how homeostasis is achieved in regenerating epithelia.

Pediatric acute gastroenteritis: understanding caregivers' experiences and information needs.

OBJECTIVES: Pediatric acute gastroenteritis (AGE) is a common condition with high health care utilization, persistent practice variation, and substantial family burden. An initial approach to resolve these issues is to understand the patient/caregiver experience of this illness. The objective of this study was to describe caregivers' experiences of pediatric AGE and identify their information needs, preferences, and priorities. METHODS: A qualitative, descriptive study was conducted. Caregivers of a child with AGE were recruited for this study in the pediatric emergency department (ED) at a tertiary hospital in a major urban centre. Individual interviews were conducted (n=15), and a thematic analysis of interview transcripts was completed using a hybrid inductive/deductive approach. RESULTS: Five major themes were identified and described: 1) caregiver management strategies; 2) reasons for going to the ED; 3) treatment and management of AGE in the ED; 4) caregivers' information needs; and 5) additional factors influencing caregivers' experiences and decision-making. A number of subthemes within each major theme were identified and described. CONCLUSIONS: This qualitative descriptive study has identified caregiver information needs, preferences, and priorities regarding pediatric AGE. This study also identified inconsistencies in the treatment and management of pediatric AGE at home and in the ED that influence health care utilization and patient outcomes related to pediatric AGE.