Activated I-BAR IRSp53 clustering controls the formation of VASP-actin–based membrane protrusions

Funding Information: Acknowledgments: The computations were supported by the University of Chicago Research Funding Information: The computations were supported by the University of Chicago Research Computing Center (RCC). We thank E. Coudrier and C. Simon for insightful discussions. We also thank F. Di Federico for handling plasmids, F. Tabarin-Cayrac for cell sorting, and A.-S. Mace for ImageJ programming assistance. F.-C.T., C.L.C., and P.B. are members of the CNRS consortium AQV. F.-C.T. and P.B. are members of the Labex Cell(n)Scale (ANR-11-LABX0038) and Paris Sciences et Lettres (ANR-10-IDEX-0001-02). We acknowledge the Cell and Tissue Imaging Core facility (PICT IBiSA), Institut Curie, member of the French National Research Infrastructure France-BioImaging (ANR10-INBS-04). This work was supported by Human Frontier Science Program (HFSP) grant RGP0005/2016 (to F.-C.T., J.M.H., G.A.V., P.L., and P.B.), Institut Curie and the Centre National de la Recherche Scientifique (CNRS) (to F.-C.T., J.M.H., and P.B.), Marie Curie actions H2020-MSCA-IF-2014 (to F.-C.T.), EMBO Long-Term fellowship ALTF 1527-2014 (to F.-C.T.), Pasteur Foundation Fellowship (to J.M.H.), Agence Nationale pour la Recherche ANR-20-CE13-0032 (to J.M.H. and P.B.) and ANR-20-CE11-0010-01 (to F.-C.T), Université Paris Sciences et Lettres-QLife Institute ANR-17-CONV-0005 Q-LIFE (to P.B.), FY 2015 Researcher Exchange Program between the Japan Society for the Promotion of Science and Academy of Finland (to Y.S.), the Takeda Science Foundation (to Y.S.), the Wesco Scientific Promotion Foundation (to Y.S.), Agence Nationale pour la Recherche ANR-18-CE13-0026-01 and ANR-21-CE13-0010-03 (to C.L.C.), Cancer Society Finland 4705949 (to P.L.), and U.S. National Institutes of Health (NIH) Institute of General Medical Sciences (NIGMS) grant R01-GM063796 (to G.A.V. and Z.J.) Publisher Copyright: Copyright © 2022 The Authors, some rights reserved.Filopodia are actin-rich membrane protrusions essential for cell morphogenesis, motility, and cancer invasion. How cells control filopodium initiation on the plasma membrane remains elusive. We performed experiments in cellulo, in vitro, and in silico to unravel the mechanism of filopodium initiation driven by the membrane curvature sensor IRSp53 (insulin receptor substrate protein of 53 kDa). We showed that full-length IRSp53 self-assembles into clusters on membranes depending on PIP2. Using well-controlled in vitro reconstitution systems, we demonstrated that IRSp53 clusters recruit the actin polymerase VASP (vasodilator-stimulated phosphoprotein) to assemble actin filaments locally on membranes, leading to the generation of actin-filled membrane protrusions reminiscent of filopodia. By pulling membrane nanotubes from live cells, we observed that IRSp53 can only be enriched and trigger actin assembly in nanotubes at highly dynamic membrane regions. Our work supports a regulation mechanism of IRSp53 in its attributes of curvature sensation and partner recruitment to ensure a precise spatial-temporal control of filopodium initiation.Peer reviewe

The impact of dietary supplementation with astaxanthin on egg quality in Atlantic cod broodstock (Gadus morhua, L.)

This study investigated the effect on egg quality of dietary supplementation of Atlantic cod broodstock with the carotenoid astaxanthin (ASTA). Duplicate groups of farm-reared Atlantic cod broodstock were fed either a control diet with no added ASTA, or an ASTA supplemented diet (73.7 mg/kg dry weight; Carophyll Pink®) for 2 months prior to peak spawning. The results indicated that ASTA uptake into eggs from the broodstock diet was highly efficient. Fish fed the diet supplemented with ASTA produced fewer batches of eggs, but the mean number per batch of eggs spawned/kg female was higher, and numbers of floating eggs and numbers of fertilised eggs per kg female in each batch were also significantly improved. A correlation between the egg ASTA content and fertilisation success of individual batches was identified. This improvement in egg quality demonstrated the potential value of ASTA supplementation of broodstock diets for cod. ASTA supplementation produced a 20% increase in the number of eggs per batch spawned, a 37% increase in the number per batch of floating eggs per kg female and a 47% increase in the number per batch of fertilised eggs per kg female. These results clearly demonstrate significant benefits of ASTA supplementation of cod broodstock feeds in terms of improved egg quality and larval production

Breast cancer management pathways during the COVID-19 pandemic: outcomes from the UK ‘Alert Level 4’ phase of the B-MaP-C study

Abstract: Background: The B-MaP-C study aimed to determine alterations to breast cancer (BC) management during the peak transmission period of the UK COVID-19 pandemic and the potential impact of these treatment decisions. Methods: This was a national cohort study of patients with early BC undergoing multidisciplinary team (MDT)-guided treatment recommendations during the pandemic, designated ‘standard’ or ‘COVID-altered’, in the preoperative, operative and post-operative setting. Findings: Of 3776 patients (from 64 UK units) in the study, 2246 (59%) had ‘COVID-altered’ management. ‘Bridging’ endocrine therapy was used (n = 951) where theatre capacity was reduced. There was increasing access to COVID-19 low-risk theatres during the study period (59%). In line with national guidance, immediate breast reconstruction was avoided (n = 299). Where adjuvant chemotherapy was omitted (n = 81), the median benefit was only 3% (IQR 2–9%) using ‘NHS Predict’. There was the rapid adoption of new evidence-based hypofractionated radiotherapy (n = 781, from 46 units). Only 14 patients (1%) tested positive for SARS-CoV-2 during their treatment journey. Conclusions: The majority of ‘COVID-altered’ management decisions were largely in line with pre-COVID evidence-based guidelines, implying that breast cancer survival outcomes are unlikely to be negatively impacted by the pandemic. However, in this study, the potential impact of delays to BC presentation or diagnosis remains unknown

Environmental tuning of the reactivity of molecules confined to polarized interfaces

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemistry, February, 2021Cataloged from the official PDF of thesis.Includes bibliographical references.The heterogenization of molecular catalysts to polarized interfaces provides an appealing approach to the design of more efficient and selective electrochemical devices. The well-defined nature of molecular catalysts renders them amenable to synthetic tuning to unravel structure-function relationships. From these studies, key insight to optimization of their activity is obtained. However, recent work has established that outer-sphere effects such as the surface structure and ligation method can impact reactivity as much as catalyst structure. This thesis explores these environmental contributions to reactivity with a particular focus on exploring the impact of electronic coupling between a molecular site and the band structure of graphitic carbon electrodes or using this coupling as a tool to understand the reactivity of molecules confined to solid-liquid interfaces. Chapters two through four explore environmental contributions to porphyrin electrocatalysis.We report on how the magnitude of electronic coupling conferred by the linkage tunes the rate of oxygen reduction catalysis. We further demonstrate solvent-dependent concerted proton electron transfer for a cobalt porphyrin attached to graphitic carbon by an alkyl-tether. Building on these results, we present a mechanistic basis for the stark differences in the selectivity and activity of heterogenized and soluble cobalt porphyrins for the CO₂ reduction reaction. Chapters five and six address charge effects at solid-liquid interfaces. In chapter five, we analyze the rate of dissociative ligand exchange for identical heterogeneous and soluble binding sites and find a modest rate enhancement that we attribute to the enhanced charge stabilization by the solid support.Chapter six details our attempt to use ambient pressure X-ray photoelectron spectroscopy to experimentally test our previously established model for catalysts strongly electronically coupled to the band states of graphitic carbon by direct measurement of the interfacial electrostatic potential drop.by Corey J. Kaminsky.Ph. D.Ph.D. Massachusetts Institute of Technology, Department of Chemistr

Long-Acting Reversible Contraception for Adolescents: A Review of Practices to Support Better Communication, Counseling, and Adherence

Julia C Durante,1,2 Jessica Sims,1,2 Jason Jarin,2,3 Melanie A Gold,4 Sarah E Messiah,5– 7 Jenny KR Francis1,2,8 1Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA; 2Children’s Health System of Texas, Dallas, TX, USA; 3Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX, USA; 4Department of Pediatrics and Department of Population & Family Health, Columbia University Irving Medical Center, New York, NY, USA; 5University of Texas Health Science Center at Houston, School of Public Health, Dallas Campus, Dallas, TX, USA; 6Center for Pediatric and Population Health, UTHealth School of Public Health, Dallas, TX, USA; 7Department of Pediatrics, McGovern Medical School, Houston, TX, USA; 8Peter O’Donnell School of Public Health, University of Texas Southwestern Medical Center, Dallas, TX, USACorrespondence: Jenny KR Francis, Department of Adolescent & Young Adult Medicine, University of Texas Southwestern/Children’s Health, 2350 N Stemmons Fwy, Ste F5200, Dallas, TX, 75207, USA, Tel +1 214-456-6790, Fax +1 214-456-2230, Email [email protected]: Long-acting reversible contraception (LARC) methods, including levonorgestrel and copper intrauterine devices (IUDs) and the subdermal contraceptive implant, are the most effective reversible forms of contraception and thus are an important aspect of adolescent pregnancy prevention. While LARC efficacy, safety, and appropriateness are supported by major medical organizations and usage rates are increasing, overall LARC uptake among United States (US) adolescents remains lower than uptake of short-acting contraceptive methods. A better understanding of the barriers affecting adolescent LARC uptake and reasons for discontinuation could help facilitate effective communication. For example, learning how to improve adolescent-centered communication, shared decision-making, and motivational counseling strategies may be the first step to improving utilization rates. This narrative review includes three sections. First, this review will describe the history, mechanisms of action, and epidemiology of adolescent LARC use in the US and globally. Next, this review will describe key factors influencing adolescent LARC uptake, reasons for discontinuation, and multilevel barriers specific to adolescent LARC use. Finally, this review will characterize communication techniques and LARC counseling strategies for adolescents in the context of a reproductive justice approach set in the health belief model framework. The distinction between moving away from a presumptive counseling approach towards an adolescent-centered, shared decision-making approach to encourage parent-adolescent sexual health communication to lay the foundation of empowering adolescent reproductive autonomy should be the underpinning of all effective reproductive communication strategies.Keywords: long-acting reversible contraception, LARC, Contraception, adolescent, pregnancy prevention, birth control, communication, contraception counselin

Characterization of Primary Cilia Formation in Human ESC-Derived Retinal Organoids

Objectives. Primary cilia are conserved organelles found in polarized mammalian cells that regulate neuronal growth, migration, and differentiation. Proper cilia formation is essential during eye development. Our previous reports found that both amacrine and retinal ganglion cells (RGCs) contain primary cilia in primate and rodent retinas. However, whether primary cilia are present in the inner retina of human retinal organoids remains unknown. The purpose of this study is to characterize the primary cilia distribution in human embryonic stem cell (hESC-derived retinal organoid development. Materials and Methods. Retinal organoids were differentiated from a hESC line, harvested at various developmental timepoints (day 44-day 266), and immunostained with antibodies for primary cilia, including Arl13b (for the axoneme), AC3, and Centrin3 (for the basal body). AP2α, Prox1, GAD67, Calretinin, GFAP, PKCα, and Chx10 antibodies as well as Brn3b-promoted tdTomato expression were used to visualize retinal cell types. Results. A group of ciliated cells were present in the inner aspects of retinal organoids from day 44 to day 266 in culture. Ciliated Chx10-positive retinal progenitor cells, GFAP-positive astrocytes, and PKCα-positive rod-bipolar cells were detected later during development (day 176 to day 266). Ciliation persisted during all stages of retinal developmental in AP2α-positive amacrine cells, but it was decreased in Brn3b-positive retinal ganglion cells (RGCs) at later time points. Additionally, AC3-positive astrocytes significantly decreased during the later stages of organoid formation. Conclusions. Amacrine cells in retinal organoids retain cilia throughout development, whereas RGC ciliation gradually and progressively decreases with organoid maturation

Activated I-BAR IRSp53 clustering controls the formation of VASP-actin–based membrane protrusions

Filopodia are actin-rich membrane protrusions essential for cell morphogenesis, motility, and cancer invasion. How cells control filopodium initiation on the plasma membrane remains elusive. We performed experiments in cellulo, in vitro, and in silico to unravel the mechanism of filopodium initiation driven by the membrane curvature sensor IRSp53 (insulin receptor substrate protein of 53 kDa). We showed that full-length IRSp53 self-assembles into clusters on membranes depending on PIP2. Using well-controlled in vitro reconstitution systems, we demonstrated that IRSp53 clusters recruit the actin polymerase VASP (vasodilator-stimulated phosphoprotein) to assemble actin filaments locally on membranes, leading to the generation of actin-filled membrane protrusions reminiscent of filopodia. By pulling membrane nanotubes from live cells, we observed that IRSp53 can only be enriched and trigger actin assembly in nanotubes at highly dynamic membrane regions. Our work supports a regulation mechanism of IRSp53 in its attributes of curvature sensation and partner recruitment to ensure a precise spatial-temporal control of filopodium initiation