The Pediatric Cell Atlas:Defining the Growth Phase of Human Development at Single-Cell Resolution

Single-cell gene expression analyses of mammalian tissues have uncovered profound stage-specific molecular regulatory phenomena that have changed the understanding of unique cell types and signaling pathways critical for lineage determination, morphogenesis, and growth. We discuss here the case for a Pediatric Cell Atlas as part of the Human Cell Atlas consortium to provide single-cell profiles and spatial characterization of gene expression across human tissues and organs. Such data will complement adult and developmentally focused HCA projects to provide a rich cytogenomic framework for understanding not only pediatric health and disease but also environmental and genetic impacts across the human lifespan

Wnt Proteins Induce Dishevelled Phosphorylation via an LRP5/6- Independent Mechanism, Irrespective of Their Ability To Stabilize β-Catenin

Wnt glycoproteins play essential roles in the development of metazoan organisms. Many Wnt proteins, such as Wnt1, activate the well-conserved canonical Wnt signaling pathway, which results in accumulation of β-catenin in the cytosol and nucleus. Other Wnts, such as Wnt5a, activate signaling mechanisms which do not involve β-catenin and are less well characterized. Dishevelled (Dvl) is a key component of Wnt/β-catenin signaling and becomes phosphorylated upon activation of this pathway. In addition to Wnt1, we show that several Wnt proteins, including Wnt5a, trigger phosphorylation of mammalian Dvl proteins and that this occurs within 20 to 30 min. Unlike the effects of Wnt1, phosphorylation of Dvl in response to Wnt5a is not concomitant with β-catenin stabilization, indicating that Dvl phosphorylation is not sufficient to activate canonical Wnt/β-catenin signaling. Moreover, neither Dickkopf1, which inhibits Wnt/β-catenin signaling by binding the Wnt coreceptors LRP5 and -6, nor dominant-negative LRP5/6 constructs could block Wnt-mediated Dvl phosphorylation. We conclude that Wnt-induced phosphorylation of Dvl is independent of LRP5/6 receptors and that canonical Wnts can elicit both LRP-dependent (to β-catenin) and LRP-independent (to Dvl) signals. Our data also present Dvl phosphorylation as a general biochemical assay for Wnt protein function, including those Wnts that do not activate the Wnt/β-catenin pathway

Truncated mutants of the putative Wnt receptor LRP6/Arrow can stabilize β-catenin independently of Frizzled proteins

Secreted signaling proteins of the Wnt family are known to regulate a diverse range of developmental processes and their signaling pathway through β-catenin is frequently activated in cancer. The identification of both Frizzled and LRP5/6 proteins as components of cell surface receptors for Wnt proteins has raised questions about their individual functions. We have investigated this issue through a structure-function analysis of Frizzled and LRP proteins that have been implicated in Wnt1 signaling. Consistent with other reports, we find that LRP6/Arrow proteins deleted for their extracellular domain are able to activate the Wnt/β-catenin signaling pathway. Importantly, our results demonstrate that this signaling from LRP6/Arrow derivatives can occur in a Frizzled- and ligand-independent manner. Furthermore we show that the PPSP motifs within the intracellular domain of LRP6 are required for signaling. In contrast to results with LRP6, overexpression of Frizzled proteins did not activate the pathway. Based on evidence of ligand binding to both Frizzled and LRP6, current models suggest that both proteins are components of a Wnt receptor complex that signals to β-catenin. In light of these models, our data imply that LRP5/6/Arrow proteins constitute the distal signal initiating component of these receptors. The results also support the notion that LRP5/6 are candidate oncogenes

Skin cleansing and topical product use in patients with epidermolysis bullosa: Results from a multicenter database

Epidermolysis bullosa (EB) comprises a group of inherited skin blistering diseases. There is currently no cure, and management includes skin protection and prevention of infection. To date, there has been no systematic investigation of home skin care practices among EB patients on a multicenter scale. This cross-sectional, observational study included data collected from patients with EB enrolled in the Epidermolysis Bullosa Characterization and Clinical Outcomes Database (EBCCOD) who provided answers to a patient-directed questionnaire between January 1, 2017, and December 31, 2017. Of 202 respondents, 130 (64.4%) had dystrophic EB, 51 (25.2%) had EB simplex, 21 (7.4%) had junctional EB, 3 (1.5%) had Kindler syndrome, and 3 (1.5%) had an unspecified subtype. Seventy-eight patients reported cleansing in plain water only (39%). Of those who used an additive in their cleansing water, 75 (57%) added salt, 71 (54%) added bleach, 36 (27%) added vinegar, and 34 (26%) endorsed the use of an "other" additive (multiple additives possible). Reported concentrations of additives ranged widely from 0.002% sodium hypochlorite and 0.002% acetic acid solutions, which are thought to have negligible effects on microbes, to 0.09% sodium hypochlorite and 0.156% acetic acid, concentrations shown to be cytotoxic. One hundred eighty-eight patients answered questions regarding topical product use (93%). Of those, 131 reported topical antimicrobial use (70%). Mupirocin and bacitracin were the most commonly reported topical antibiotics (59, 58 [31.4%, 30.9%], respectively). These findings highlight the variety of skin care routines and frequent use of topical antimicrobials among EB patients and have potential implications for antibiotic resistance. The reported range of bleach and vinegar additives to cleansing water, including cytotoxic concentrations, emphasizes the need for clear and optimized skin cleansing recommendations

Dermatology COVID-19 Registries:Updates and Future Directions

During the COVID-19 pandemic, rapid, real-world evidence is essential for the development of knowledge and subsequent public health response. In dermatology, provider- and patient-facing registries focused on COVID-19 have been important sources of research and new information aimed at guiding optimal patient care. The seven dermatology registries included in this update now include over 8,000 case reports sourced from physicians and patients from countries all over the world

Association of Demographic Factors and Infantile Hemangioma Characteristics With Risk of PHACE Syndrome

Importance: A 2010 prospective study of 108 infants estimated the incidence of PHACE (posterior fossa malformations, hemangioma, arterial anomalies, cardiac defects, eye anomalies) syndrome to be 31% in children with facial infantile hemangiomas (IHs) of at least 22 cm2. There is little evidence regarding the associations among IH characteristics, demographic characteristics, and risk of PHACE syndrome. Objectives: To evaluate demographic characteristics and comorbidities in a large cohort of patients at risk for PHACE syndrome and assess the clinical features of large head and neck IH that may be associated with a greater risk of a diagnosis of PHACE syndrome. Design, setting, and participants: This multicenter, retrospective cohort study assessed all patients with a facial, head, and/or neck IH who were evaluated for PHACE syndrome from August 1, 2009, to December 31, 2014, at 13 pediatric dermatology referral centers across North America. Data analysis was performed from June 15, 2017, to February 29, 2020. Main outcomes and measures: The main outcome was presence or absence of PHACE syndrome. Data included age at diagnosis, sex, patterns of IH presentation (including size, segment location, and depth), diagnostic procedures and results, and type and number of associated anomalies. Results: A total of 238 patients (mean [SD] age, 2.96 [4.71] months; 184 [77.3%] female) were included in the analysis; 106 (44.5%) met the criteria for definite (n = 98) or possible (n = 8) PHACE syndrome. A stepwise linear regression model found that a surface area of 25 cm2 or greater (odds ratio [OR] 2.99; 95% CI, 1.49-6.02) and involvement of 3 or more locations (OR, 17.96; 95% CI, 6.10-52.85) to be statistically significant risk factors for PHACE syndrome. Involvement of the parotid gland (OR, 0.39; 95% CI, 0.18-0.85) and segment S2 (OR, 0.38; 95% CI, 0.16-0.91) was associated with a lower risk. Race and ethnicity may also be associated with PHACE syndrome risk, although more studies are needed. Conclusions and relevance: This cohort study further described factors associated with both a higher and lower risk of PHACE syndrome. The presence of multiple anatomical sites and large surface area were associated with greater risk, whereas S2 or parotid IHs were associated with lower, but still potential, risk. These findings can help in counseling families and decision-making regarding evaluation of infants with large head and neck IHs

Methotrexate for inflammatory skin disease in pediatric patients: Consensus treatment guidelines

Methotrexate (MTX) is a readily accessible drug, first used in 1948 and employed for a wide variety of indications since then. However, despite widespread off-label use, FDA labeling does not include approved indications for the use of MTX for many inflammatory skin diseases in pediatric patients, including morphea, psoriasis, atopic dermatitis, and alopecia areata, among others. Without published treatment guidelines, some clinicians may be hesitant to use MTX off-label, or uncomfortable prescribing MTX in this population. To address this unmet need, an expert consensus committee was convened to develop evidence- and consensus-based guidelines for use of MTX to treat pediatric inflammatory skin disease. Clinicians with experience and expertise in clinical research, drug development, and treating inflammatory skin disease in pediatric patients with MTX were recruited. Five committees were created based on major topic areas: (1) indications and contraindications, (2) dosing, (3) interactions with immunizations and medications, (4) adverse effects (potential for and management of), and (5) monitoring needs. Pertinent questions were generated and addressed by the relevant committee. The entire group participated in a modified Delphi process to establish agreement on recommendations for each question. The committee developed 46 evidence- and consensus-based recommendations, each with \u3e70% agreement among members, across all five topics. These are presented in tables and text, along with a discussion of supporting literature, and level of evidence. These evidence- and consensus-based recommendations will support safe and effective use of MTX for the underserved population of pediatric patients who may benefit from this valuable, time-honored medication