Protocols for Subtomogram Averaging of Membrane Proteins in the Dynamo Software Package

Cryo-electron tomography allows low-resolution three-dimensional (3D) viewing of cellular organelles and macromolecular complexes present as multiple copies within a tomogram. These structures are computationally extracted and averaged in order to obtain high-resolution 3D structures, and provide a map of their spatial distribution and interaction with their biological microenvironment. To do so, we apply the user-friendly Dynamo software package on a tomographic data set. Dynamo acts as a modular toolbox adaptable to different biological scenarios, allowing a custom designed pipeline for subtomogram averaging. Here, we use as a textbook example the mitochondrial docking site of the positive-strand RNA Flock house nodavirus (FHV) to describe how Dynamo coordinates several basic steps in the subtomogram averaging workflow. Our framework covers specific strategies to deal with additional issues in subtomogram averaging as tomographic data management, 3D surface visualization, automatic assignment of asymmetry and inherent loss of Fourier information in presence of preferential views

Targeted gene therapy and cell reprogramming in Fanconi anemia

Altres ajuts: European Regional Development FEDER Funds, Italian Ministry of Health, Fondo de Investigaciones Sanitarias, Dirección General de Investigación de la Comunidad de Madrid S2010/BMD-2420, La Fundació Privada La Marató de TV3 121430/31/32, Marató de TV3 464/C/2012Gene targeting is progressively becoming a realistic therapeutic alternative in clinics. It is unknown, however, whether this technology will be suitable for the treatment of DNA repair deficiency syndromes such as Fanconi anemia (FA), with defects in homology-directed DNA repair. In this study, we used zinc finger nucleases and integrase-defective lentiviral vectors to demonstrate for the first time that FANCA can be efficiently and specifically targeted into the AAVS1 safe harbor locus in fibroblasts from FA-A patients. Strikingly, up to 40% of FA fibroblasts showed gene targeting 42 days after gene editing. Given the low number of hematopoietic precursors in the bone marrow of FA patients, gene-edited FA fibroblasts were then reprogrammed and re-differentiated toward the hematopoietic lineage. Analyses of gene-edited FA-iPSCs confirmed the specific integration of FANCA in the AAVS1 locus in all tested clones. Moreover, the hematopoietic differentiation of these iPSCs efficiently generated disease-free hematopoietic progenitors. Taken together, our results demonstrate for the first time the feasibility of correcting the phenotype of a DNA repair deficiency syndrome using gene-targeting and cell reprogramming strategies

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

Meeting abstrac

Self-injury and suicidal behavior in children and youth population: learning from the pandemic

Introduction: Suicidal behavior and self-harm are increasing in children and adolescents. Non-suicidal self-harm are a dysfunctional method of emotional regulation, and it must be distinguished from suicidal behaviors.Methods: Narrative review of the current situation on suicide and self-harm in Spain. Descrip-tive study of suicidal behaviors in pediatric emergencies.Results: Mental health consultations were analyzed (March-2019 to March-2020 and March -2020 to March-2021) in a multicentric study of the Spanish Society of Pediatric Emergencies (SEUP), finding a 122% increase of the diagnosis of > and 56% of >. In another prospective analysis, 281 attempts were recorded, with the patient profile being: female (90.1%), 14.8 years old, 34.9% without previous psychiatric diagnosis; 57.7% with previous suicidal behavior. The presence of psychia-tric disorders, especially depression, and previous attempts, are the best-known risk factors for suicidal behavior, although other factors are involved (family, personal or social). Pediatri-cians should be trained to deal with questions about suicide and acquire the skills to conduct an interview with a supportive and empathetic attitude. In Spain, suicide prevention plans are heterogeneous among communities, and there is not a unified national suicide prevention plan. Conclusions: Primary, hospital and mental health care resources for pediatric population should be strengthened to prevent suicidal behaviors. Specific training for school staff, and child and adolescent psychiatry training for pediatricians and nurses are crucial in the prevention of suicide in children and adolescent population

IQM-22110, a new selective inhibitor of KChIP3 and its electrophysiological effects on Kv4.3, Kv4.3/KChIP3 and Kv4.3/KChIP2 currents

Kv4 channels generate rapidly activating and inactivating outward currents responsible for the repolarization of both cardiac and neuronal action potentials through ITO (transient outward current) and IA (A-type Kþ current), respectively. Kv4 dysfunctions have been identified in both cardiac and neuronal diseases (Brugada syndrome, atrial fibrillation, epilepsy or Alzheimer’s disease). However, Kv4 channels need to assemble with regulatory subunits to fully reproduce ITO and IA currents. Among them, we will focus on KChIPs (potassium channel interacting proteins), being KChIP3 predominant in the brain and KChIP2 in both brain and heart. The assembly of these regulatory subunits not only modulates the biophysical properties of the channel, but also its pharmacology. For this reason, we have analysed the electrophysiological effects of IQM-22110 (a novel KChIP3 ligand) on the currents generated by Kv4.3, Kv4.3/KChIP3 and Kv4.3/KChIP2 channels. CHO cells were transiently transfected, and the potassium currents were recorded using the whole-cell patchclamp technique. Our results indicate that IQM-22110 exerts differential effects on these currents, being the concentration-dependence of inhibition modified, exhibiting a biphasic curve when KChIP3 is present, thus suggesting two binding sites for IQM-22110 in this complex. With molecular dynamics and site-directed mutagenesis, we have identified the binding pocket corresponding to the high affinity site. Also, we have demonstrated that IQM-22110 binds to the closed-active state of the channel. In this study: i) IQM-22110 has proven to be a selective inhibitor of Kv4.3/KChIP3 at low concentrations, and ii) a new binding pocket for selective KChIP3/Kv4.3 ligands has been identified

Cerebral Corpora amylacea are dense membranous labyrinths containing structurally preserved cell organelles

Abstract Corpora amylacea are cell-derived structures that appear physiologically in the aged human brain. While their histological identification is straightforward, their ultrastructural composition and microenvironment at the nanoscale have remained unclear so far, as has their relevance to aging and certain disease states that involve the sequestration of toxic cellular metabolites. Here, we apply correlative serial block-face scanning electron microscopy and transmission electron tomography to gain three-dimensional insight into the ultrastructure and surrounding microenvironment of cerebral Corpora amylacea in the human brainstem and hippocampal region. We find that cerebral Corpora amylacea are composed of dense labyrinth-like sheets of lipid membranes, contain vesicles as well as morphologically preserved mitochondria, and are in close proximity to blood vessels and the glymphatic system, primarily within the cytoplasm of perivascular glial cells. Our results clarify the nature of cerebral Corpora amylacea and provide first hints on how they may arise and develop in the aging brain

Soraphen A: a broad-spectrum antiviral natural product with potent anti-hepatitis C virus activity

BACKGROUND & AIMS: Soraphen A (SorA) is a myxobacterial metabolite that inhibits the acetyl-CoA carboxylase, a key enzyme in lipid biosynthesis. We have previously identified SorA to efficiently inhibit the human immunodeficiency virus (HIV). The aim of the present study was to evaluate the capacity of SorA and analogues to inhibit hepatitis C virus (HCV) infection. METHODS: SorA inhibition capacity was evaluated in vitro using cell culture derived HCV, HCV pseudoparticles and subgenomic replicons. Infection studies were performed in the hepatoma cell line HuH7/Scr and in primary human hepatocytes. The effects of SorA on membranous web formation were analysed by electron microscopy./nRESULTS:/nSorA potently inhibits HCV infection at nanomolar concentrations. Obtained EC50 values were 0.70 nM with a HCV reporter genome, 2.30 nM with wild-type HCV and 2.52 nM with subgenomic HCV replicons. SorA neither inhibited HCV RNA translation nor HCV entry, as demonstrated with subgenomic HCV replicons and HCV pseudoparticles, suggesting an effect on HCV replication. Consistent with this, evidence was obtained that SorA interferes with formation of the membranous web, the site of HCV replication. Finally, a series of natural and synthetic SorA analogues helped to establish a first structure-activity relationship./nCONCLUSIONS:/nSorA has a very potent anti-HCV activity. Since it also interferes with the membranous web formation, SorA is an excellent tool to unravel the mechanism of HCV replication.The authors are supported by grants BFU2013-44629-R (to JD, GK and GPV), SAF2013-46077-R (to/nAM and JM), both from the Spanish Ministry of Economy and Competitiveness and FEDER, and from the German Centre for Infection Research (DZIF, to MB and RM