Top Paper Panel

Panel Chair: Kerry Byrnes-Loinette Papers presented: Quantifying apoptosis induced by the fusion of EWS-FLI1 by means of terminal deoxynucleotidyl transferase (TdT) dUTP Nick-End Lableing (TUNEL) using the zebrafish model by Rozen Gilerman How Economic Indicators Influence Mexican Immigration, and Mexican Immigration Success, in the United States by Daisy Jaimez The Electric Spacecraft Propulsion System by Alexander J. Harper Abstract: Spacecraft propulsion systems play a pivotal role in the modern Aerospace Industry as they are responsible for allowing craft to move and navigate and therefore operate as they are intended to. While chemical systems are more well known, electric propulsion systems stand as the next step in the journey to the stars and are seeing more widespread use on spacecraft than ever before. An exploration of the properties and inner workings of electric ion drives demonstrates how they operate at a greater efficiency than chemical rockets and therefore the most sustainable and economically feasible option for extra-atmospheric maneuvers. An exploration of non-ionic drives demonstrates how engineers and scientists are taking the next step to develop creative and resourceful new methods of propulsion, and that these methods are the future of spacecraft propulsion. Biblical Allusions in the Brothers Karamazov by Lindy Winter Fyodor Dostoyevsky’s The Brothers Karamazov, written in 1880 in the Russian language (although translated to English in 1912), is the last book that Dostoyevsky wrote. This passionate novel covers a multitude of significant themes that reflect Dostoyevsky’s own religious and philosophical views such as free will, the existence of God, and ethics. Throughout the novel, however, these themes could not be expressed without the use of biblical allusions, which are indirect references to the bible. Therefore, in order to fully comprehend Dostoyevsky’s purpose for this final novel, this essay will examine the question: to what extent and why does Fyodor Dostoyevsky implement biblical allusions in his novel, The Brothers Karamazov? Answering this question requires a complete and thorough investigation of reviews and criticisms on Dostoyevsky’s novel, background of the author’s life, context of the time period, and an exploration of religious texts that relate to the book. Primary sources, such as scriptural accounts in The Bible, are used to prove the existence of biblical allusions as well as discover a relationship between the novel and biblical text. Furthermore, secondary sources such as literary analyses are critically observed in order to understand the reasoning for Dostoyevsky’s use of biblical allusions. The research primarily focuses on the overall implementation of biblical references in the novel and why they are used. Thorough analysis and investigation of the previously mentioned strategies shows that Dostoyevsky ultimately implemented biblical allusions in a highly profuse and distinctive manner, allowing his readers to understand character relationships on a deeper level, realize his personal religious and philosophical views, and further appreciate the role of faith in the entire novel

IRS-2 Deficiency Impairs NMDA Receptor-Dependent Long-term Potentiation

The beneficial effects of insulin and insulin-like growth factor I on cognition have been documented in humans and animal models. Conversely, obesity, hyperinsulinemia, and diabetes increase the risk for neurodegenerative disorders including Alzheimer's disease (AD). However, the mechanisms by which insulin regulates synaptic plasticity are not well understood. Here, we report that complete disruption of insulin receptor substrate 2 (Irs2) in mice impairs long-term potentiation (LTP) of synaptic transmission in the hippocampus. Basal synaptic transmission and paired-pulse facilitation were similar between the 2 groups of mice. Induction of LTP by high-frequency conditioning tetanus did not activate postsynaptic N-methyl-D-aspartate (NMDA) receptors in hippocampus slices from Irs2−/− mice, although the expression of NR2A, NR2B, and PSD95 was equivalent to wild-type controls. Activation of Fyn, AKT, and MAPK in response to tetanus stimulation was defective in Irs2−/− mice. Interestingly, IRS2 was phosphorylated during induction of LTP in control mice, revealing a potential new component of the signaling machinery which modulates synaptic plasticity. Given that IRS2 expression is diminished in Type 2 diabetics as well as in AD patients, these data may reveal an explanation for the prevalence of cognitive decline in humans with metabolic disorders by providing a mechanistic link between insulin resistance and impaired synaptic transmission

Lambert-Eaton syndrome IgG inhibits transmitter release via P/Q Ca²⁺ channels

Objective: To determine whether immunoglobulin G (IgG) from patients with Lambert Eaton Syndrome (LEMS) decreases action-potential evoked synaptic vesicle exocytosis, and whether the effect is mediated by P/Q-type voltage-gated calcium channels (VGCCs). Methods: IgG was obtained from four patients with LEMS (3M, 1F), including two patients with lung malignancy. Antibodies against P/Q-type VGCCs were detected in all four patients, and Ntype in two. We incubated neuronal cultures with LEMS IgG and determined the size of the total recycling pool of synaptic vesicles and the rate of action-potential evoked exocytosis using fluorescence imaging of the amphiphilic dye SynaptoRed C1. Pooled IgG from healthy volunteers was used as a control. We repeated the experiments on synapses lacking P/Q-type calcium channels from a Cacna1a knockout mouse to determine whether these channels account for the pathogenic effect of LEMS IgG. Results: LEMS IgG had no effect on the total recycling pool size but significantly reduced the rate of action potential-evoked synaptic exocytosis in wild type neurons when compared to neurons treated with control IgG. In contrast, LEMS IgG had no effect on the rate of synaptic vesicle exocytosis in neurons lacking P/Q-type channels. Conclusions: These data provide direct evidence that LEMS IgG inhibits neurotransmitter release by acting on P/Q-type VGCCs

Low Stress Ion Conductance Microscopy of Sub-Cellular Stiffness.

Directly examining subcellular mechanics whilst avoiding excessive strain of a live cell requires the precise control of light stress on very small areas, which is fundamentally difficult. Here we use a glass nanopipet out of contact with the plasma membrane to both exert the stress on the cell and also accurately monitor cellular compression. This allows the mapping of cell stiffness at a lateral resolution finer than 100 nm. We calculate the stress a nanopipet exerts on a cell as the sum of the intrinsic pressure between the tip face and the plasma membrane plus its direct pressure on any glycocalyx, both evaluated from the gap size in terms of the ion current decrease. A survey of cell types confirms that an intracellular pressure of approximately 120 Pa begins to detach the plasma membrane from the cytoskeleton and reveals that the first 0.66 ± 0.09 μm of compression of a neuron cell body is much softer than previous methods have been able to detect.Biotechnology and Biological Sciences Research Council (Grant ID: BB/L006227/1), Engineering and Physical Sciences Research Council (Grant ID: EP/H01098X/1), Medical Research Council (Grant IDs: G0701057, MR/K501372/1), Herchel Smith Postdoctoral Fellowship, Royal Society of Chemistry Analytical Chemistry Trust Fun

Emery-Dreifuss muscular dystrophy Type 1 is associated with a high risk of malignant ventricular arrhythmias and end-stage heart failure

\ua9 2023 The Author(s). Published by Oxford University Press on behalf of the European Society of Cardiology.Background and Aims: Emery-Dreifuss muscular dystrophy (EDMD) is caused by variants in EMD (EDMD1) and LMNA (EDMD2). Cardiac conduction defects and atrial arrhythmia are common to both, but LMNA variants also cause end-stage heart failure (ESHF) and malignant ventricular arrhythmia (MVA). This study aimed to better characterize the cardiac complications of EMD variants. Methods: Consecutively referred EMD variant-carriers were retrospectively recruited from 12 international cardiomyopathy units. MVA and ESHF incidences in male and female variant-carriers were determined. Male EMD variant-carriers with a cardiac phenotype at baseline (EMDCARDIAC) were compared with consecutively recruited male LMNA variant-carriers with a cardiac phenotype at baseline (LMNACARDIAC). Results: Longitudinal follow-up data were available for 38 male and 21 female EMD variant-carriers [mean (SD) ages 33.4 (13.3) and 43.3 (16.8) years, respectively]. Nine (23.7%) males developed MVA and five (13.2%) developed ESHF during a median (inter-quartile range) follow-up of 65.0 (24.3-109.5) months. No female EMD variant-carrier had MVA or ESHF, but nine (42.8%) developed a cardiac phenotype at a median (inter-quartile range) age of 58.6 (53.2-60.4) years. Incidence rates for MVA were similar for EMDCARDIAC and LMNACARDIAC (4.8 and 6.6 per 100 person-years, respectively; log-rank P =. 49). Incidence rates for ESHF were 2.4 and 5.9 per 100 person-years for EMDCARDIAC and LMNACARDIAC, respectively (log-rank P =. 09). Conclusions: Male EMD variant-carriers have a risk of progressive heart failure and ventricular arrhythmias similar to that of male LMNA variant-carriers. Early implantable cardioverter defibrillator implantation and heart failure drug therapy should be considered in male EMD variant-carriers with cardiac disease

Extracellular cysteine disulfide bond break at Cys122 disrupts PIP2-dependent Kir2.1 channel function and leads to arrhythmias in Andersen-Tawil Syndrome

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Extracellular Kir2.1C122Y Mutant Upsets Kir2.1-PIP2 Bonds and Is Arrhythmogenic in Andersen-Tawil Syndrome.

BACKGROUND Andersen-Tawil syndrome type 1 is a rare heritable disease caused by mutations in the gene coding the strong inwardly rectifying K+ channel Kir2.1. The extracellular Cys (cysteine)122-to-Cys154 disulfide bond in the channel structure is crucial for proper folding but has not been associated with correct channel function at the membrane. We evaluated whether a human mutation at the Cys122-to-Cys154 disulfide bridge leads to Kir2.1 channel dysfunction and arrhythmias by reorganizing the overall Kir2.1 channel structure and destabilizing its open state. METHODS We identified a Kir2.1 loss-of-function mutation (c.366 A>T; p.Cys122Tyr) in an ATS1 family. To investigate its pathophysiological implications, we generated an AAV9-mediated cardiac-specific mouse model expressing the Kir2.1C122Y variant. We employed a multidisciplinary approach, integrating patch clamping and intracardiac stimulation, molecular biology techniques, molecular dynamics, and bioluminescence resonance energy transfer experiments. RESULTS Kir2.1C122Y mice recapitulated the ECG features of ATS1 independently of sex, including corrected QT prolongation, conduction defects, and increased arrhythmia susceptibility. Isolated Kir2.1C122Y cardiomyocytes showed significantly reduced inwardly rectifier K+ (IK1) and inward Na+ (INa) current densities independently of normal trafficking. Molecular dynamics predicted that the C122Y mutation provoked a conformational change over the 2000-ns simulation, characterized by a greater loss of hydrogen bonds between Kir2.1 and phosphatidylinositol 4,5-bisphosphate than wild type (WT). Therefore, the phosphatidylinositol 4,5-bisphosphate-binding pocket was destabilized, resulting in a lower conductance state compared with WT. Accordingly, on inside-out patch clamping, the C122Y mutation significantly blunted Kir2.1 sensitivity to increasing phosphatidylinositol 4,5-bisphosphate concentrations. In addition, the Kir2.1C122Y mutation resulted in channelosome degradation, demonstrating temporal instability of both Kir2.1 and NaV1.5 proteins. CONCLUSIONS The extracellular Cys122-to-Cys154 disulfide bond in the tridimensional Kir2.1 channel structure is essential for the channel function. We demonstrate that breaking disulfide bonds in the extracellular domain disrupts phosphatidylinositol 4,5-bisphosphate-dependent regulation, leading to channel dysfunction and defects in Kir2.1 energetic stability. The mutation also alters functional expression of the NaV1.5 channel and ultimately leads to conduction disturbances and life-threatening arrhythmia characteristic of Andersen-Tawil syndrome type 1.The authors thank the Centro Nacional de Investigaciones Cardiovasculares (CNIC) Viral Vectors Unit for producing the adeno-associated virus serotype 9. Confocal experiments were conducted at the CNIC Microscopy and Dynamic Imaging Unit. The authors thank the CNIC Bioinformatics Unit for generating the in silico homology modeling simulations, F-function analysis, and helpful discussions. The authors also thank the Centro de Supercomputación de Galicia for the use of the Finis Terrae III supercomputer to perform molecular dynamics studies. The CNIC was supported by the Instituto de Salud Carlos III, the Ministerio de Ciencia, Innovación y Universidades, and the Pro CNIC Foundation and is a Severo Ochoa Center of Excellence (grant CEX2020-001041-S funded by MICIU/AEI/10.13039/501100011033). This work was supported by the National heart, Lung and Blood Institute under National Institutes of Health (NIH) grant R01HL163943; the La Caixa Banking Foundation project code HR18-00304 (grant LCF/PR/HR19/52160013); grants PI-FIS-2020, PI20/01220, PI-FIS-2023, and PI23/01039 from the Instituto de Salud Carlos III and cofunded by the Fondo Europeo de Desarrollo Regional (FEDER) and the European Union, respectively; grants PID2020-116935RB-I00 and BFU2016-75144-R funded by MICIU/AEI/10.13039/501100011033; the Fundación La Marató de TV3 (736/C/2020) amb el suport de la Fundació La Marató de TV3; the CIBER (Centro de Investigación Biomédica en Red) de Enfermedades Cardiovasculares (grant CB16/11/00458); the European Union’s Horizon 2020 grant agreement GA-965286; and the Program S2022/BMD7229-CM ARCADIACM funded by the Comunidad de Madrid to J. Jalife; grant PID2021-126423OB-C22 (to M. Martín-Martínez) funded by MICIU/AEI/10.13039/501100011033; and European Regional Development Fund (ERDF) grant PID2022-137214OB-C22 (to M. Gutierrez-Rodríguez) funded by MICIU/AEI/10.13039/501100011033. The imaging studies were performed in the TRIMA@CNIC (Infraestructura de Imagen Traslacional Avanzada del CNIC) node of the ICTS ReDIB (Infraestructuras Científicas y Técnicas Singulares: Red Distribuida de Imagen Biomédica) grant ICTS-2018- 04-CNIC-16 funded by MICIU/AEI/10.13039/501100011033 and ERDF, and project EQC2018-005070-P funded by MICIU/AEI/10.13039/501100011033 and FEDER. A.I. Moreno-Manuel holds an formación profesional universitaria (FPU) contract (FPU20/01569) from the Ministerio de Universidades. J.M. Ruiz Robles holds an FPU contract (FPU22/03253) from the Ministerio de Universidades. L.K. Gutiérrez holds an FPI contract (PRE2018-083530) from the Ministerio de Economía y Competitividad de España cofunded by the Fondo Social Europeo, attached to project SEV-2015-0505-18-2. I. Martínez-Carrascoso holds a PFIS (Contratos predoctorales de formación en investigación en salud) contract (FI21/00243) funded by Instituto de Salud Carlos III and the Fondo Social Europeo Plus cofunded by the European Union. M.L. Vera-Pedrosa held contract PEJD-2019-PRE/BMD15982 funded by the Consejería de Educación e Investigación de la Comunidad de Madrid y Fondo Social Europeo.S