Tracing the origin of everything.

Highly potent adult stem cells fuel lifelong tissue homeostasis and regeneration in many aquatic invertebrates, yet their developmental backstories remain obscure. In this issue of Cell, Kimura and colleagues reveal the cellular origin of adult pluripotent stem cells and propose a molecular trajectory for their specification during acoel embryogenesis.

Prospectively Isolated Tetraspanin+ Neoblasts Are Adult Pluripotent Stem Cells Underlying Planaria Regeneration.

Proliferating cells known as neoblasts include pluripotent stem cells (PSCs) that sustain tissue homeostasis and regeneration of lost body parts in planarians. However, the lack of markers to prospectively identify and isolate these adult PSCs has significantly hampered their characterization. We used single-cell RNA sequencing (scRNA-seq) and single-cell transplantation to address this long-standing issue. Large-scale scRNA-seq of sorted neoblasts unveiled a novel subtype of neoblast (Nb2) characterized by high levels of PIWI-1 mRNA and protein and marked by a conserved cell-surface protein-coding gene, tetraspanin 1 (tspan-1). tspan-1-positive cells survived sub-lethal irradiation, underwent clonal expansion to repopulate whole animals, and when purified with an anti-TSPAN-1 antibody, rescued the viability of lethally irradiated animals after single-cell transplantation. The first prospective isolation of an adult PSC bridges a conceptual dichotomy between functionally and molecularly defined neoblasts, shedding light on mechanisms governing in vivo pluripotency and a source of regeneration in animals. VIDEO ABSTRACT.

Ets-1 transcription factor regulates glial cell regeneration and function in planarians.

Glia play multifaceted roles in nervous systems in response to injury. Depending on the species, extent of injury and glial cell type in question, glia can help or hinder the regeneration of neurons. Studying glia in the context of successful regeneration could reveal features of pro-regenerative glia that could be exploited for new human therapies. Planarian flatworms completely regenerate their nervous systems after injury - including glia - and thus provide a strong model system for exploring glia in the context of regeneration. Here, we report that planarian glia regenerate after neurons, and that neurons are required for correct glial numbers and localization during regeneration. We also identify the planarian transcription factor-encoding gene ets-1 as a key regulator of glial cell maintenance and regeneration. Using ets-1 (RNAi) to perturb glia, we show that glial loss is associated with altered neuronal gene expression, impeded animal movement and impaired nervous system architecture - particularly within the neuropil. Importantly, our work reveals the inter-relationships of glia and neurons in the context of robust neural regeneration.

Planarian Anatomy Ontology: a resource to connect data within and across experimental platforms.

As the planarian research community expands, the need for an interoperable data organization framework for tool building has become increasingly apparent. Such software would streamline data annotation and enhance cross-platform and cross-species searchability. We created the Planarian Anatomy Ontology (PLANA), an extendable relational framework of defined Schmidtea mediterranea (Smed) anatomical terms used in the field. At publication, PLANA contains over 850 terms describing Smed anatomy from subcellular to system levels across all life cycle stages, in intact animals and regenerating body fragments. Terms from other anatomy ontologies were imported into PLANA to promote interoperability and comparative anatomy studies. To demonstrate the utility of PLANA as a tool for data curation, we created resources for planarian embryogenesis, including a staging series and molecular fate-mapping atlas, and the Planarian Anatomy Gene Expression database, which allows retrieval of a variety of published transcript/gene expression data associated with PLANA terms. As an open-source tool built using FAIR (findable, accessible, interoperable, reproducible) principles, our strategy for continued curation and versioning of PLANA also provides a platform for community-led growth and evolution of this resource.

Prevalence of Self-reported Neurologic and Ocular Symptoms in Early Syphilis Cases.

BACKGROUND: Neurosyphilis, a complication of syphilis, can occur at any stage of infection. Measuring the prevalence of neurosyphilis is challenging, and there are limited data on the prevalence of neurologic or ocular symptoms among patients with syphilis. We sought to describe the prevalence of neurologic and/or ocular symptoms among early syphilis (ES) cases and the clinical management of symptomatic cases enrolled in the STD Surveillance Network (SSuN) Neuro/Ocular Syphilis Surveillance project. METHODS: Persons diagnosed with ES were selected for interviews based on current health department protocols in 5 participating SSuN jurisdictions from November 2016 through October 2017. All interviewed ES cases were screened for self-reported neurologic and/or ocular symptoms. Additional clinical information on diagnostic testing and treatment for cases concerning for neurosyphilis/ocular syphilis was obtained from providers. RESULTS: Among 9123 patients with ES who were interviewed, 151 (1.7%; 95% confidence interval [CI], 1.4%-1.9%) reported ≥ 1 neurologic or ocular symptom. Of the 53 (35%) who underwent lumbar puncture, 22 (42%) had documented abnormal cerebrospinal fluid, of which 21 (95%) were treated for neurosyphilis/ocular syphilis. Among the remaining 98 symptomatic patients with no documented lumbar puncture (65%), 12 (12%) were treated for and/or clinically diagnosed with neurosyphilis/ocular syphilis. CONCLUSIONS: We observed a low prevalence of self-reported neurologic and/or ocular symptoms in interviewed ES cases. Approximately one-third of ES cases who self-reported symptoms underwent further recommended diagnostic evaluation. Understanding barriers to appropriate clinical evaluation is important to ensuring appropriate management of patients with possible neurologic and/or ocular manifestations of syphilis.

The actin-binding protein profilin is required for germline stem cell maintenance and germ cell enclosure by somatic cyst cells.

Specialized microenvironments, or niches, provide signaling cues that regulate stem cell behavior. In the Drosophila testis, the JAK-STAT signaling pathway regulates germline stem cell (GSC) attachment to the apical hub and somatic cyst stem cell (CySC) identity. Here, we demonstrate that chickadee, the Drosophila gene that encodes profilin, is required cell autonomously to maintain GSCs, possibly facilitating localization or maintenance of E-cadherin to the GSC-hub cell interface. Germline specific overexpression of Adenomatous Polyposis Coli 2 (APC2) rescued GSC loss in chic hypomorphs, suggesting an additive role of APC2 and F-actin in maintaining the adherens junctions that anchor GSCs to the niche. In addition, loss of chic function in the soma resulted in failure of somatic cyst cells to maintain germ cell enclosure and overproliferation of transit-amplifying spermatogonia.

The transcriptional regulator lola is required for stem cell maintenance and germ cell differentiation in the Drosophila testis.

Stem cell behavior is regulated by extrinsic signals from specialized microenvironments, or niches, and intrinsic factors required for execution of context-appropriate responses to niche signals. Here we show that function of the transcriptional regulator longitudinals lacking (lola) is required cell autonomously for germline stem cell and somatic cyst stem cell maintenance in the Drosophila testis. In addition, lola is also required for proper execution of key developmental transitions during male germ cell differentiation, including the switch from transit amplifying progenitor to spermatocyte growth and differentiation, as well as meiotic cell cycle progression and spermiogenesis. Different lola isoforms, each having unique C-termini and zinc finger domains, may control different aspects of proliferation and differentiation in the male germline and somatic cyst stem cell lineages.

The transcription factor Eyes absent is a protein tyrosine phosphatase.

Post-translational modifications provide sensitive and flexible mechanisms to dynamically modulate protein function in response to specific signalling inputs. In the case of transcription factors, changes in phosphorylation state can influence protein stability, conformation, subcellular localization, cofactor interactions, transactivation potential and transcriptional output. Here we show that the evolutionarily conserved transcription factor Eyes absent (Eya) belongs to the phosphatase subgroup of the haloacid dehalogenase (HAD) superfamily, and propose a function for it as a non-thiol-based protein tyrosine phosphatase. Experiments performed in cultured Drosophila cells and in vitro indicate that Eyes absent has intrinsic protein tyrosine phosphatase activity and can autocatalytically dephosphorylate itself. Confirming the biological significance of this function, mutations that disrupt the phosphatase active site severely compromise the ability of Eyes absent to promote eye specification and development in Drosophila. Given the functional importance of phosphorylation-dependent modulation of transcription factor activity, this evidence for a nuclear transcriptional coactivator with intrinsic phosphatase activity suggests an unanticipated method of fine-tuning transcriptional regulation.

Functional dissection of eyes absent reveals new modes of regulation within the retinal determination gene network.

The retinal determination (RD) gene network encodes a group of transcription factors and cofactors necessary for eye development. Transcriptional and posttranslational regulation of RD family members is achieved through interactions within the network and with extracellular signaling pathways, including epidermal growth factor receptor/RAS/mitogen-activated protein kinase (MAPK), transforming growth factor beta/DPP, Wingless, Hedgehog, and Notch. Here we present the results of structure-function analyses that reveal novel aspects of Eyes absent (EYA) function and regulation. We find that the conserved C-terminal EYA domain negatively regulates EYA transactivation potential, and that GROUCHO-SINE OCULIS (SO) interactions provide another mechanism for negative regulation of EYA-SO target genes. We have mapped the transactivation potential of EYA to an internal proline-, serine-, and threonine-rich region that includes the EYA domain 2 (ED2) and two MAPK phosphorylation consensus sites and demonstrate that activation of the RAS/MAPK pathway potentiates transcriptional output of EYA and the EYA-SO complex in certain contexts. Drosophila S2 cell two-hybrid assays were used to describe a novel homotypic interaction that is mediated by EYA's N terminus. Our data suggest that EYA requires homo- and heterotypic interactions and RAS/MAPK signaling responsiveness to ensure context-appropriate RD gene network activity.

Embryonic origin of adult stem cells required for tissue homeostasis and regeneration.

Planarian neoblasts are pluripotent, adult somatic stem cells and lineage-primed progenitors that are required for the production and maintenance of all differentiated cell types, including the germline. Neoblasts, originally defined as undifferentiated cells residing in the adult parenchyma, are frequently compared to embryonic stem cells yet their developmental origin remains obscure. We investigated the provenance of neoblasts during Schmidtea mediterranea embryogenesis, and report that neoblasts arise from an anarchic, cycling piwi-1+ population wholly responsible for production of all temporary and definitive organs during embryogenesis. Early embryonic piwi-1+ cells are molecularly and functionally distinct from neoblasts: they express unique cohorts of early embryo enriched transcripts and behave differently than neoblasts in cell transplantation assays. Neoblast lineages arise as organogenesis begins and are required for construction of all major organ systems during embryogenesis. These subpopulations are continuously generated during adulthood, where they act as agents of tissue homeostasis and regeneration.

An examination of attitudes, knowledge, and clinical practices among Pennsylvania pediatricians regarding breastfeeding and smoking.

BACKGROUND AND OBJECTIVE: The most recent American Academy of Pediatrics policy statement clearly supports breastfeeding for smoking mothers. The impact of this recommendation on pediatricians' counseling and prescribing practices is unclear. This study describes Pennsylvania pediatricians' attitudes, knowledge, and practices regarding breastfeeding, maternal smoking, and smoking cessation. METHODS: A descriptive study was conducted using a web-based, anonymous survey. The survey consisted of three clinical vignettes followed by knowledge and attitude questions. RESULTS: Among 296 respondents, more than half reported one or more conversations about breastfeeding and smoking in the past year. Most were comfortable counseling on breastfeeding, but few were comfortable counseling about smoking and breastfeeding. Respondents scored poorly on five knowledge items; 27% answered zero items correctly, and only 21% answered four or five items correctly. Less than half reported breastfeeding was safe for smoking mothers. Compared to pediatricians with high knowledge scores, those with a low score were less likely to tell a smoking mother that breastfeeding is safe (38% vs. 69%, p < 0.01) and more likely to recommend formula feeding (19% vs. 3%, p < 0.01). Most pediatricians were uncertain about the safety of nicotine replacement therapy and bupropion (Zyban, GalxoSmithKline, Research Triangle Park, NC) with breastfeeding. CONCLUSIONS: Pennsylvania pediatricians lack knowledge and comfort related to the topic of breastfeeding and maternal smoking. Additional efforts to inform and educate pediatricians on the subjects of breastfeeding, maternal tobacco use, and smoking cessation products are needed.

What do mothers think about concurrent breast-feeding and smoking?

OBJECTIVE: According to newer policies of the American Academy of Pediatrics, smoking is not contraindicated with breast-feeding, yet smokers initiate and maintain breast-feeding less often than nonsmokers. We sought to describe maternal knowledge and attitudes regarding concurrent breast-feeding and smoking or nicotine replacement therapy (NRT) and to evaluate the association between maternal smoking and infant feeding practices. METHODS: Mothers bringing children <13 months old for an appointment completed a 24-item anonymous survey that addressed knowledge, attitudes, and practices about concurrent breast-feeding and smoking/NRT. RESULTS: Among 204 survey completers, 63% were African American, 52% had never breast-fed, and 54% had never smoked. Regardless of smoking status, 19% were aware of the recommendation to smoke after breast-feeding; most did not know that nicotine gum (42%) or patch (40%) transfers less or about the same amount of nicotine into breast milk than smoking a pack per day. Most mothers (80%) believed that women should not smoke any cigarettes if breast-feeding; current smokers (25%) were more likely than former (10%) or never smokers (11%) to find it acceptable to smoke one or more cigarettes per day (P = .03). Only 2% found it acceptable to use NRT while breast-feeding. Among ever breast-feeders, 10% stopped breast-feeding because of smoking. Over half of recent or current smokers reported that smoking affected their infant feeding decision. CONCLUSIONS: Mothers in this sample believe that women who smoke or take NRT should not breast-feed. Smoking status affected women's infant feeding practices. Correction of misinformation could increase breast-feeding rates.

Extending, and repositioning, a thermochemical ladder: high-level quantum chemical calculations on the sodium cation affinity scale.

High-level ab initio quantum chemical calculations, at the CP-dG2thaw level of theory, are reported for coordination of Na+ to a wide assortment of small organic and inorganic ligands. The ligands range in size from H to C6H6, and include 22 of the ligands for which precise relative sodium ion binding free energies have been determined by recent Fourier transform ion cyclotron resonance and guided ion beam studies. Agreement with the relative experimental values is excellent (+/-1.1 kJ mol(-1)), and agreement with the absolute scale (obtained when these relative values are pegged to the CH3NH2 "anchor" value measured in a high-pressure mass spectrometric study) is only marginally poorer, with CP-dG2thaw values exceeding the absolute experimental DeltaG(298) values by an average of 2.1 kJ mol(-1). The excellent agreement between experiment and the CP-dG2thaw technique also suggests that the additional 97 ligands surveyed here (which, in many cases, are not readily susceptible to laboratory investigation) can also be reliably fitted to the existing experimental scale. However, while CP-dG2thaw and the experimental ladder are in close accord, a small set of higher level ab initio calculations on sodium ion/ligand complexes (including several values obtained here using the W1 protocol) suggests that the CP-dG2thaw values are themselves too low by approximately 2.5 kJ mol(-1), thereby implying that the accepted laboratory values are typically 4.6 kJ mol(-1) too low. The present work also highlights the importance of Na+/ligand binding energy determinations (whether by experimental or theoretical approaches) on a case-by-case basis: trends in increasing binding energy along homologous series of compounds are not reliably predictable, nor are binding site preferences or chelating tendencies in polyfunctional compounds.