522 results on '"Samaddar S"'
Search Results
252. BEHAVIOR OF THE COMPLEX REFRACTIVE INDEX OF AN ISOTROPIC PLASMA.
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Samaddar, S
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- 1968
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253. DISTORTED WAVE BORN APPROXIMATION ANALYSIS OF $sup 58$Ni(d,p)$sup 59$Ni.
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Samaddar, S
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- 1969
254. COUPLED OPTICAL AND ACOUSTIC WAVES IN A COMPRESSIBLE PLASMA WITH BOUNDARIES
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Samaddar, S
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- 1965
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255. ORTHOGONALITY PROPERTIES OF MODES IN A COMPRESSIBLE PARTIALLY IONIZED PLASMA
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Samaddar, S
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- 1964
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256. OPTICAL POTENTIALS FOR $sup 3$He AND TRITON.
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Samaddar, S
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- 1969
257. OPTICAL POTENTIAL FOR DEUTERONS.
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Samaddar, S
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- 1968
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258. THEORETICAL MODEL OF A MICROWAVE PROBE FOR A RE-ENTRY PLASMA.
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Samaddar, S
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- 1970
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259. EXCITATION OF ELECTRO-ACOUSTICAL WAVES IN A TWO-FLUID COMPRESSIBLE PLASMA
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Samaddar, S
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- 1964
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260. EXCITATION OF WAVES IN A COMPRESSIBLE PARTIALLY IONIZED PLASMA BY SOURCES OF DIFFERENT KINDS.
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Samaddar, S
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- 1966
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261. Complex angular momentum methods for composite particle--nucleus elastic scattering.
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Samaddar, S
- Published
- 1973
262. EXCITATION OF ELECTRO-ACOUSTIC LATERAL WAVES IN A COMPRESSIBLE PLASMA BY A NON-ELECTROMAGNETIC SOURCE.
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Samaddar, S
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- 1967
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263. A NOTE ON WAVE PHENOMENA DUE TO A MOVING AND OSCILLATING DIPOLE IN A COMPRESSIBLE PLASMA COLUMN
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Samaddar, S
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- 1963
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264. Sensitivity of elements of the symmetry energy of nuclear matter to the properties of neutron-rich systems.
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Mondal, C., Agrawal, B. K., De, J. N., and Samaddar, S. K.
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NUCLEAR energy , *NUCLEAR matter , *BINDING energy - Abstract
The sensitivity of nuclear symmetry energy elements at the saturation density to the binding energies of ultra-neutron-rich nuclei (neutron-to-proton ratio ~2) and the maximum mass of a neutron star is explored within a relativistic mean field model. Values of the interaction parameters governing the isovector strengths and the symmetry elements are determined in tighter bounds. Assessments based on the sensitivity matrix reveal that the properties of extreme neutron-rich systems play a predominant role in narrowing down the uncertainties in the various symmetry energy parameters. The calculations are extended over a wide range of nuclear matter density, and the results are discussed. [ABSTRACT FROM AUTHOR]
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- 2016
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265. STUDY OF SURFACE WAVES ALONG THE BOUNDARY OF TWO COAXIAL CYLINDRICAL DIELECTRIC COLUMNS IN A CIRCULAR CYLINDRICAL METALLIC WAVEGUIDE WITH EXCITATION BY A MAGNETIC RING CURRENT
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Samaddar, S
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- 1960
266. Chitosan/siRNA nanoparticles targeting PARP-1 attenuate Neuroinflammation and apoptosis in hyperglycemia-induced oxidative stress in Neuro2a cells.
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Redhwan MAM, Hariprasad MG, Samaddar S, Bafail DA, Hard SAAA, and Guha S
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Hyperglycemia induces an excessive production of superoxide by the mitochondria's electron-transport chain triggers several pathways of injury contributing to the development of diabetic complications. This increase in oxidative and nitrosative stress triggers the activation of PARP-1, a nuclear enzyme, through mechanisms such as DNA damage. siRNA-chitosan nanoparticles were formed based on electrostatic interaction, their particle size, zeta potential, STEM, and cellular uptake were characterized. Neuro2a cells were treated with low glucose (LG) and high glucose (HG) for 24 and 48 h. Neuro2a cells were pre-treated with negative siRNA, naked siRNA, siRNA-Lipofectamine™300, and ChNPs-5. qRT-PCR was used to analyze the expression of regulatory, inflammatory, and apoptotic biomarkers. The siRNA-chitosan complex at the weight ratio 1:3000 were approximately uniform spheres with particle size 150.5 nm and a positive zeta potential of about +41.5 mV. The uptake of FITC-labeled nanoparticles into Neuro2a cells was visualized using fluorescence microscopy with no significant cytotoxicity compared to the control cells. High glucose stimulation of Neuro2a cells increased PARP1 expression, and with siRNA-ChNP (1:3000) treatment, significant inhibition of PARP1 expression is observed that consequently reversed the expression of regulatory genes like SIRT1, FOXO1, FOXO3, and p53. PARP-1 inhibition reduced HG-induced inflammatory response, including NF-kB, IL6, IL1β, TNFα, iNOS, and TGF-β expression, and HG-induced apoptosis response, such as Cas-3, Cas-9, BAK, BAX, and AIF expression. This study highlights the crucial role of siRNA delivery via ChNPs and PARP-1 inhibition in hyperglycemia-induced oxidative stress in Neuro2a cells and PARP-1 inhibition may be a feasible strategy for the treatment of hyperglycemia-induced oxidative stress., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)
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- 2024
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267. Tick extracellular vesicles undermine epidermal wound healing during hematophagy.
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Marnin L, Valencia LM, Bogale HN, Laukaitis-Yousey HJ, Rolandelli A, Ferraz CR, O'Neal AJ, Schmitter-Sánchez AD, Cuevas EB, Nguyen TT, Leal-Galvan B, Rickert DM, Mendes MT, Samaddar S, Butler LR, Singh N, Cabrera Paz FE, Oliver JD, Jameson JM, Munderloh UG, Oliva Chávez AS, Mulenga A, Park S, Serre D, and Pedra JHF
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Wound healing has been extensively studied through the lens of inflammatory disorders and cancer, but limited attention has been given to hematophagy and arthropod-borne diseases. Hematophagous ectoparasites, including ticks, subvert the wound healing response to maintain prolonged attachment and facilitate blood-feeding. Here, we unveil a strategy by which extracellular vesicles (EVs) ensure blood-feeding and arthropod survival in three medically relevant tick species. We demonstrate through single cell RNA sequencing and murine genetics that wildtype animals infested with EV-deficient Ixodes scapularis display a unique population of keratinocytes with an overrepresentation of pathways connected to wound healing. Tick feeding affected keratinocyte proliferation in a density-dependent manner, which relied on EVs and dendritic epidermal T cells (DETCs). This occurrence was linked to phosphoinositide 3-kinase activity, keratinocyte growth factor (KGF) and transforming growth factor β (TGF-β) levels. Collectively, we uncovered a strategy employed by a blood-feeding arthropod that impairs the integrity of the epithelial barrier, contributing to ectoparasite fitness.
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- 2024
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268. Neurotrophins in Peripheral Neuropathy: Exploring Pathophysiological Mechanisms and Emerging Therapeutic Opportunities.
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Samaddar S, Redhwan MAM, Eraiah MM, and Koneri R
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Neuropathies, which encompass a wide array of peripheral nervous system disorders, present significant challenges due to their varied causes, such as metabolic diseases, toxic exposures, and genetic mutations. This review article, focused on the critical role of neurotrophins in peripheral neuropathy, highlights the intricate balance of neurotrophins necessary for nerve health and the pathophysiological consequences when this balance is disturbed. Neurotrophins, including Nerve Growth Factor (NGF), Brain-Derived Neurotrophic Factor (BDNF), Neurotrophin- 3 (NT-3), and Neurotrophin-4 (NT-4), are essential for neuronal survival, axonal growth, and synaptic plasticity. Their signaling pathways are crucial for maintaining peripheral nervous system integrity, primarily via the Tropomyosin receptor kinase (Trk) receptors and the p75 neurotrophin receptor p75(NTR). Dysregulation of neurotrophins is implicated in various neuropathies, such as diabetic neuropathy and chemotherapy-induced peripheral neuropathy, leading to impaired nerve function and regeneration. Understanding neurotrophin signaling intricacies and their alterations in neuropathic conditions is crucial for identifying novel therapeutic targets. Recent advancements illuminate neurotrophins' potential as therapeutic agents, promising diseasemodifying treatments by promoting neuronal survival, enhancing axonal regeneration, and improving functional recovery post-nerve injury. However, translating these molecular insights into effective clinical applications faces challenges, including delivery methods, target specificity, and the instability of protein-based therapies., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)
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- 2024
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269. Bacterial reprogramming of tick metabolism impacts vector fitness and susceptibility to infection.
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Samaddar S, Rolandelli A, O'Neal AJ, Laukaitis-Yousey HJ, Marnin L, Singh N, Wang X, Butler LR, Rangghran P, Kitsou C, Cabrera Paz FE, Valencia L, R Ferraz C, Munderloh UG, Khoo B, Cull B, Rosche KL, Shaw DK, Oliver J, Narasimhan S, Fikrig E, Pal U, Fiskum GM, Polster BM, and Pedra JHF
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- Animals, Mice, Lyme Disease microbiology, Glycolysis, Metabolomics, Humans, Genetic Fitness, Symbiosis, Ixodes microbiology, Anaplasma phagocytophilum metabolism, Anaplasma phagocytophilum genetics, Rickettsia genetics, Rickettsia metabolism, Borrelia burgdorferi genetics, Borrelia burgdorferi metabolism
- Abstract
Arthropod-borne pathogens are responsible for hundreds of millions of infections in humans each year. The blacklegged tick, Ixodes scapularis, is the predominant arthropod vector in the United States and is responsible for transmitting several human pathogens, including the Lyme disease spirochete Borrelia burgdorferi and the obligate intracellular rickettsial bacterium Anaplasma phagocytophilum, which causes human granulocytic anaplasmosis. However, tick metabolic response to microbes and whether metabolite allocation occurs upon infection remain unknown. Here we investigated metabolic reprogramming in the tick ectoparasite I. scapularis and determined that the rickettsial bacterium A. phagocytophilum and the spirochete B. burgdorferi induced glycolysis in tick cells. Surprisingly, the endosymbiont Rickettsia buchneri had a minimal effect on bioenergetics. An unbiased metabolomics approach following A. phagocytophilum infection of tick cells showed alterations in carbohydrate, lipid, nucleotide and protein metabolism, including elevated levels of the pleiotropic metabolite β-aminoisobutyric acid. We manipulated the expression of genes associated with β-aminoisobutyric acid metabolism in I. scapularis, resulting in feeding impairment, diminished survival and reduced bacterial acquisition post haematophagy. Collectively, we discovered that metabolic reprogramming affects interspecies relationships and fitness in the clinically relevant tick I. scapularis., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)
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- 2024
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270. Post-translational modification by the Pgf glycosylation machinery modulates Streptococcus mutans OMZ175 physiology and virulence.
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de Mojana di Cologna N, Andresen S, Samaddar S, Archer-Hartmann S, Rogers AM, Kajfasz JK, Ganguly T, Garcia BA, Saengpet I, Peterson AM, Azadi P, Szymanski CM, Lemos JA, and Abranches J
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- Glycosylation, Virulence, Animals, Humans, Rats, Adhesins, Bacterial metabolism, Adhesins, Bacterial genetics, Saliva microbiology, Dental Caries microbiology, Gene Expression Regulation, Bacterial, Carrier Proteins, Streptococcus mutans genetics, Streptococcus mutans metabolism, Streptococcus mutans pathogenicity, Protein Processing, Post-Translational, Biofilms growth & development, Operon, Bacterial Proteins metabolism, Bacterial Proteins genetics
- Abstract
Streptococcus mutans is commonly associated with dental caries and the ability to form biofilms is essential for its pathogenicity. We recently identified the Pgf glycosylation machinery of S. mutans, responsible for the post-translational modification of the surface-associated adhesins Cnm and WapA. Since the four-gene pgf operon (pgfS-pgfM1-pgfE-pgfM2) is part of the S. mutans core genome, we hypothesized that the scope of the Pgf system goes beyond Cnm and WapA glycosylation. In silico analyses and tunicamycin sensitivity assays suggested a functional overlap between the Pgf machinery and the rhamnose-glucose polysaccharide synthesis pathway. Phenotypic characterization of pgf mutants (ΔpgfS, ΔpgfE, ΔpgfM1, ΔpgfM2, and Δpgf) revealed that the Pgf system is important for biofilm formation, surface charge, membrane stability, and survival in human saliva. Moreover, deletion of the entire pgf operon (Δpgf strain) resulted in significantly impaired colonization in a rat oral colonization model. Using Cnm as a model, we showed that Cnm is heavily modified with N-acetyl hexosamines but it becomes heavily phosphorylated with the inactivation of the PgfS glycosyltransferase, suggesting a crosstalk between these two post-translational modification mechanisms. Our results revealed that the Pgf machinery contributes to multiple aspects of S. mutans pathobiology that may go beyond Cnm and WapA glycosylation., (© 2023 John Wiley & Sons Ltd.)
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- 2024
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271. Disseminated cerebral cryptococcoma mimicking glioblastoma - A case report."
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Uppar A, Andiperumal Raj P, Veenakumari HB, Arghadip S, Dawn Bharath R, and S N
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- Humans, Female, Middle Aged, Diagnosis, Differential, Fatal Outcome, Brain pathology, Brain diagnostic imaging, Brain microbiology, Brain Neoplasms diagnosis, Antifungal Agents therapeutic use, COVID-19 diagnosis, Cryptococcus gattii isolation & purification, Cryptococcosis diagnosis, Cryptococcosis microbiology, Glioblastoma diagnosis
- Abstract
We discuss a rare instance of cryptococcoma caused by Cryptococcus gattii in a 55-year-old woman initially treated for suspected COVID bronchopneumonia. The diagnosis posed a challenge due to vague symptoms and unclear imaging findings suggesting malignancy. Postoperative samples confirmed the presence of Cryptococcus gattii through culture of brain tissue and blood. Appropriate therapy was initiated, but despite treatment, it led to a fatal outcome. The case emphasizes the crucial role of microbiologist in early diagnosis of fungal infections of Central Nervous System. Additionally, the delayed diagnosis in immunocompetent individuals highlights the critical need for early recognition and intervention to mitigate potentially fatal outcomes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Indian Association of Medical Microbiologists. Published by Elsevier B.V. All rights reserved.)
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- 2024
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272. Genetic manipulation of an Ixodes scapularis cell line.
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Singh N, Rolandelli A, O'Neal AJ, Butler LR, Samaddar S, Laukaitis-Yousey HJ, Butnaru M, Mohr SE, Perrimon N, and Pedra JHF
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- Animals, Humans, Cell Line, Mammals, Ixodes, Borrelia burgdorferi genetics, Anaplasma phagocytophilum genetics, Rickettsia
- Abstract
Although genetic manipulation is one of the hallmarks of model organisms, its applicability to non-model species has remained difficult due to our limited understanding of their fundamental biology. For instance, manipulation of a cell line originated from the black-legged tick Ixodes scapularis, an arthropod that serves as a vector for several human pathogens, has yet to be established. Here, we demonstrate the successful genetic modification of the commonly used tick ISE6 line through ectopic expression and clustered regularly interspaced palindromic repeats [(CRISPR)/CRISPR-associated protein 9 (Cas9)] genome editing. We performed ectopic expression using nucleofection and attained CRISPR-Cas9 editing via homology-dependent recombination. Targeting the E3 ubiquitin ligase x-linked inhibitor of apoptosis ( xiap ) and its substrate p47 led to an alteration in molecular signaling within the immune deficiency network and increased infection of the rickettsial agent Anaplasma phagocytophilum in I. scapularis ISE6 cells. Collectively, our findings complement techniques for the genetic engineering of I. scapularis ticks , which currently limit efficient and scalable molecular genetic screens in vivo .IMPORTANCEGenetic engineering in arachnids has lagged compared to insects, largely because of substantial differences in their biology. This study unveils the implementation of ectopic expression and CRISPR-Cas9 gene editing in a tick cell line. We introduced fluorescently tagged proteins in ISE6 cells and edited its genome via homology-dependent recombination. We ablated the expression of xiap and p47 , two signaling molecules present in the immune deficiency (IMD) pathway of Ixodes scapularis . Impairment of the tick IMD pathway, an analogous network of the tumor necrosis factor receptor in mammals, led to enhanced infection of the rickettsial agent Anaplasma phagocytophilum . Altogether, our findings provide a critical technical resource to the scientific community to enable a deeper understanding of biological circuits in the black-legged tick I. scapularis ., Competing Interests: The authors declare no conflict of interest.
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- 2024
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273. Tick hemocytes have a pleiotropic role in microbial infection and arthropod fitness.
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Rolandelli A, Laukaitis-Yousey HJ, Bogale HN, Singh N, Samaddar S, O'Neal AJ, Ferraz CR, Butnaru M, Mameli E, Xia B, Mendes MT, Butler LR, Marnin L, Cabrera Paz FE, Valencia LM, Rana VS, Skerry C, Pal U, Mohr SE, Perrimon N, Serre D, and Pedra JHF
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- Animals, Hemocytes, Arthropods, Ixodes microbiology, Borrelia burgdorferi physiology, Anaplasma phagocytophilum, Lyme Disease
- Abstract
Uncovering the complexity of systems in non-model organisms is critical for understanding arthropod immunology. Prior efforts have mostly focused on Dipteran insects, which only account for a subset of existing arthropod species in nature. Here we use and develop advanced techniques to describe immune cells (hemocytes) from the clinically relevant tick Ixodes scapularis at a single-cell resolution. We observe molecular alterations in hemocytes upon feeding and infection with either the Lyme disease spirochete Borrelia burgdorferi or the rickettsial agent Anaplasma phagocytophilum. We reveal hemocyte clusters exhibiting defined signatures related to immunity, metabolism, and proliferation. Depletion of phagocytic hemocytes affects hemocytin and astakine levels, two I. scapularis hemocyte markers, impacting blood-feeding, molting behavior, and bacterial acquisition. Mechanistically, astakine alters hemocyte proliferation, whereas hemocytin affects the c-Jun N-terminal kinase (JNK) signaling pathway in I. scapularis. Altogether, we discover a role for tick hemocytes in immunophysiology and provide a valuable resource for comparative biology in arthropods., (© 2024. The Author(s).)
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- 2024
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274. Endoscopic Endonasal Trans-Sphenoidal Minimally Invasive Pituitary Surgery with Image Guided Navigation System (Igns): Learning Experience of Ent Surgeon: First Author.
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Ghosh D, Majhi S, Choudhary A, Samaddar S, Guha A, Kumar S, Maitra M, and Sengupta A
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Introduction- Endoscopic minimally invasive pituitary surgery (MIPS) is advantageous over microscopic technique, as it provides superior close up, wide angle view of surgical target area. Image guided navigation system (IGNS) guides the surgeon to localize the lesion. In the present study we analyzed the Image Guided Surgical procedure and outcome of Endoscopic minimally invasive pituitary surgery and shared our experiences regarding disease clearance., Materials and Methods: During the period of April 2015 to August 2022 a total 104 patients, diagnosed with pituitary adenoma underwent surgery and further followed up in a multidisciplinary team approach in a tertiary care hospital of Kolkata, India. The data obtained were reviewed statistically to satisfy the study objectives., Results: Total 104 operations were done on 98 patients and total cases taken for calculation and analysis was 98, which consist of 11 microadenomas, 81 macroadenomas. Among 35 patients with normal preoperative hormonal assay, one patient developed postoperative hypopituitarism. Among 6 patients with preoperative hypopituitarism 4 patients (66.6%) recovered after surgery. Overall, 85 cases had total disease clearance as detected on post-operative MRI. In functioning pituitary adenoma (FPA) clinical and endocrinological improvement occurred after primary surgery in 85.36% (n = 35) and after revision surgery it was 84.44% (n = 38). Macroadenomas, giant adenomas were found to have statistically significant higher risk of incomplete disease clearance but large adenomas do not have statistically higher risk of incomplete clearance., Conclusion: IGNS requires extra time for setup, but with proper registration of tracker instruments it adds precision to the surgery. IGNS supplements endoscopic visualization with localization of target lesion by real time stereotactic feedback using preset preoperative imaging data, thus increasing accuracy, safety and effectiveness of minimally invasive surgery., Competing Interests: Competing interestsThe Authors disclose that there is no conflict of interest. No Funding was obtained for conducting the study. The data that support the findings of this study are available on request from the corresponding author., (© Association of Otolaryngologists of India 2023. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.)
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- 2024
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275. Interfacial Pressure and Viscoelasticity of Antibodies and Their Correlation to Long-Term Stability in Formulation.
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Pham KG, Thompson BR, Wang T, Samaddar S, Qian KK, Liu Y, and Wagner NJ
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- Elastic Modulus, Rheology, Antibodies, Monoclonal chemistry, Water chemistry
- Abstract
Monoclonal antibodies (mAbs) form viscoelastic gel-like layers at the air-water interface due to their amphiphilic nature, and this same protein characteristic can lead to undesired aggregation of proteins in therapeutic formulations. We hypothesize that the interfacial viscoelasticity and surface pressure of mAbs at the air-water interface will correlate with their long-term stability. To test this hypothesis, the interfacial viscoelastic rheology and surface pressure of five different antibodies with varying visible particle counts from a three-year stability study were measured. We find that both the surface pressures and interfacial elastic moduli correlate well with the long-time mAb solution stability within a class of mAbs with the interfacial elastic moduli being particularly sensitive to discriminate between stable and unstable mAbs across a range of formulations. Furthermore, X-ray reflectivity was used to gain insight into the interfacial structure of mAbs at the air-water interface, providing a possible molecular mechanism to explain the relationship between interfacial elastic moduli and the long-term stability.
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- 2023
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276. Small interference (RNAi) technique: Exploring its clinical applications, benefits and limitations.
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Redhwan MAM, M G H, Samaddar S, Hard SAAA, Yadav V, Mukherjee A, and Kumar R
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- Humans, RNA Interference, RNA, Small Interfering therapeutic use, Lung, Neoplasms therapy, Neoplasms drug therapy, Virus Diseases genetics
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Background: Small interference RNA (siRNA) has emerged as the most desired method for researchers and clinicians who wish to silence a specific gene of interest and has been extensively developed as a therapeutic agent. This review points to collecting all clinical trials on siRNA and understanding its benefits, pharmacokinetics and safety by reading articles published in the last 5 years., Materials and Methods: Searching in the PubMed database using 'siRNA' and 'in vivo' with limits to articles published in the previous 5 years, article type 'clinical trials' and language 'English' to acquire papers on in vivo studies on siRNA approaches. Features of siRNA clinical trials registered at https://clinicaltrials.gov/ were analysed., Results: So far, 55 clinical studies have been published on siRNA. Many published clinical trials on siRNA showed tolerability, safety and effectiveness in treating cancers like breast, lung, colon, and other organs and other diseases like viral infections and hereditary diseases. Many different routes of administration can silence many genes at the same time. Limitations and uncertainties associated with siRNA treatment include the effectiveness of cellular uptake, precise targeting of the intended tissue or cell and prompt elimination from the body., Conclusions: The siRNA or RNAi method will be one of the most critical and influential techniques to fight against many different diseases. Although the RNAi approach has certain advantages, it also has limitations concerning clinical applications. Overcoming these limitations remains a daunting challenge., (© 2023 Stichting European Society for Clinical Investigation Journal Foundation. Published by John Wiley & Sons Ltd.)
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- 2023
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277. Defective quality control autophagy in Hyperhomocysteinemia promotes ER stress and consequent neuronal apoptosis through proteotoxicity.
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Kaur B, Sharma PK, Chatterjee B, Bissa B, Nattarayan V, Ramasamy S, Bhat A, Lal M, Samaddar S, Banerjee S, and Roy SS
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- Animals, Zebrafish, Apoptosis, Autophagy, Homocysteine, Quality Control, Hyperhomocysteinemia
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Homocysteine (Hcy), produced physiologically in all cells, is an intermediate metabolite of methionine and cysteine metabolism. Hyperhomocysteinemia (HHcy) resulting from an in-born error of metabolism that leads to accumulation of high levels of Hcy, is associated with vascular damage, neurodegeneration and cognitive decline. Using a HHcy model in neuronal cells, primary cortical neurons and transgenic zebrafish, we demonstrate diminished autophagy and Hcy-induced neurotoxicity associated with mitochondrial dysfunction, fragmentation and apoptosis. We find this mitochondrial dysfunction is due to Hcy-induced proteotoxicity leading to ER stress. We show this sustained proteotoxicity originates from the perturbation of upstream autophagic pathways through an aberrant activation of mTOR and that protetoxic stress act as a feedforward cues to aggravate a sustained ER stress that culminate to mitochondrial apoptosis in HHcy model systems. Using chemical chaperones to mitigate sustained ER stress, Hcy-induced proteotoxicity and consequent neurotoxicity were rescued. We also rescue neuronal lethality by activation of autophagy and thereby reducing proteotoxicity and ER stress. Our findings pave the way to devise new strategies for the treatment of neural and cognitive pathologies reported in HHcy, by either activation of upstream autophagy or by suppression of downstream ER stress. Video Abstract., (© 2023. BioMed Central Ltd., part of Springer Nature.)
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- 2023
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278. Tick hemocytes have pleiotropic roles in microbial infection and arthropod fitness.
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Rolandelli A, Laukaitis-Yousey HJ, Bogale HN, Singh N, Samaddar S, O'Neal AJ, Ferraz CR, Butnaru M, Mameli E, Xia B, Mendes MT, Butler LR, Marnin L, Cabrera Paz FE, Valencia LM, Rana VS, Skerry C, Pal U, Mohr SE, Perrimon N, Serre D, and Pedra JHF
- Abstract
Uncovering the complexity of systems in non-model organisms is critical for understanding arthropod immunology. Prior efforts have mostly focused on Dipteran insects, which only account for a subset of existing arthropod species in nature. Here, we describe immune cells or hemocytes from the clinically relevant tick Ixodes scapularis using bulk and single cell RNA sequencing combined with depletion via clodronate liposomes, RNA interference, Clustered Regularly Interspaced Short Palindromic Repeats activation (CRISPRa) and RNA-fluorescence in situ hybridization (FISH). We observe molecular alterations in hemocytes upon tick infestation of mammals and infection with either the Lyme disease spirochete Borrelia burgdorferi or the rickettsial agent Anaplasma phagocytophilum . We predict distinct hemocyte lineages and reveal clusters exhibiting defined signatures for immunity, metabolism, and proliferation during hematophagy. Furthermore, we perform a mechanistic characterization of two I. scapularis hemocyte markers: hemocytin and astakine . Depletion of phagocytic hemocytes affects hemocytin and astakine levels, which impacts blood feeding and molting behavior of ticks. Hemocytin specifically affects the c-Jun N-terminal kinase (JNK) signaling pathway, whereas astakine alters hemocyte proliferation in I. scapularis . Altogether, we uncover the heterogeneity and pleiotropic roles of hemocytes in ticks and provide a valuable resource for comparative biology in arthropods.
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- 2023
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279. CRISPR Based Programmable RNA Editing in Primary Hippocampal Neurons.
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Ravichandran K, Khargonkar T, Samaddar S, and Banerjee S
- Abstract
Investigating the RNA regulation landscape primarily relies on understanding how RNA-protein interactions are governed in various cell types, including neurons. Analysis of RNA-protein interactions in physiological environments warrants the development of new tools that rely on RNA manipulation. Recently, a CRISPR-based RNA-editing tool (dCas13b-ADAR2
DD ) was developed to mitigate disease-associated point mutations in cell lines. Here, we explored the targeted sequence editing potential of the tool (dCas13b-ADAR2DD system) by adapting it to manipulate RNA function to visualize RNA editing in primary hippocampal neurons. This two-component system includes a programmable guide RNA (gRNA) complementary to the target RNA and a catalytically dead version of the Cas13b enzyme fused to ADAR. The RNA editing protocol outlined in this article relies on gRNA-dependent targeting of the dCas13b-ADAR fusion protein to the mutant form of the Dendra2 transcript. Dendra2 is not required for intrinsic cellular functioning. It was ectopically expressed for fluorescent detection as a proof-of-principle demonstration of targeted RNA editing. We first abrogated the fluorescence of Dendra2 by introducing a nonsense mutation that precludes the formation of the functional protein. To visualize the efficacy of the RNA editing in neurons, we used the dCas13b-ADAR2DD system to edit specific nucleotides within the Dendra2 mRNA to restore the amino acid codes critical for Dendra2 fluorescence. This method lays the foundation for future studies on the dynamics of activity-induced RNA-protein interactions in neurons and can be extended to manipulate the endogenous RNome in diverse neuronal subtypes. Furthermore, this methodology will enable investigators to visualize the spatial and temporal resolution of RNA-protein interactions without altering the genomes via conventional methods. © 2023 Wiley Periodicals LLC. Support Protocol: Preparation of mouse primary hippocampal culture Basic Protocol: Targeted editing of RNA., (© 2023 Wiley Periodicals LLC.)- Published
- 2023
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280. Muscleblind-1 interacts with tubulin mRNAs to regulate the microtubule cytoskeleton in C. elegans mechanosensory neurons.
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Puri D, Sharma S, Samaddar S, Ravivarma S, Banerjee S, and Ghosh-Roy A
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- Animals, RNA, Messenger, Cytoskeleton genetics, Microtubules genetics, Neurons, Tubulin genetics, Caenorhabditis elegans genetics
- Abstract
Regulation of the microtubule cytoskeleton is crucial for the development and maintenance of neuronal architecture, and recent studies have highlighted the significance of regulated RNA processing in the establishment and maintenance of neural circuits. In a genetic screen conducted using mechanosensory neurons of C. elegans, we identified a mutation in muscleblind-1/mbl-1 as a suppressor of loss of kinesin-13 family microtubule destabilizing factor klp-7. Muscleblind-1(MBL-1) is an RNA-binding protein that regulates the splicing, localization, and stability of RNA. Our findings demonstrate that mbl-1 is required cell-autonomously for axon growth and proper synapse positioning in the posterior lateral microtubule (PLM) neuron. Loss of mbl-1 leads to increased microtubule dynamics and mixed orientation of microtubules in the anterior neurite of PLM. These defects are also accompanied by abnormal axonal transport of the synaptic protein RAB-3 and reduction of gentle touch sensation in mbl-1 mutant. Our data also revealed that mbl-1 is genetically epistatic to mec-7 (β tubulin) and mec-12 (α tubulin) in regulating axon growth. Furthermore, mbl-1 is epistatic to sad-1, an ortholog of BRSK/Brain specific-serine/threonine kinase and a known regulator of synaptic machinery, for synapse formation at the correct location of the PLM neurite. Notably, the immunoprecipitation of MBL-1 resulted in the co-purification of mec-7, mec-12, and sad-1 mRNAs, suggesting a direct interaction between MBL-1 and these transcripts. Additionally, mbl-1 mutants exhibited reduced levels and stability of mec-7 and mec-12 transcripts. Our study establishes a previously unknown link between RNA-binding proteins and cytoskeletal machinery, highlighting their crucial roles in the development and maintenance of the nervous system., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Puri et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
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- 2023
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281. Translating Molecular Biology Discoveries to Develop Targeted Cancer Interception in Barrett's Esophagus.
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Samaddar S, Buckles D, Saha S, Zhang Q, and Bansal A
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- Humans, Risk Factors, Metaplasia, Barrett Esophagus metabolism, Esophageal Neoplasms pathology, Adenocarcinoma metabolism
- Abstract
Esophageal adenocarcinoma (EAC) is a rapidly increasing lethal tumor. It commonly arises from a metaplastic segment known as Barrett's esophagus (BE), which delineates the at-risk population. Ample research has elucidated the pathogenesis of BE and its progression from metaplasia to invasive carcinoma; and multiple molecular pathways have been implicated in this process, presenting several points of cancer interception. Here, we explore the mechanisms of action of various agents, including proton pump inhibitors, non-steroidal anti-inflammatory drugs, metformin, and statins, and explain their roles in cancer interception. Data from the recent AspECT trial are discussed to determine how viable a multipronged approach to cancer chemoprevention would be. Further, novel concepts, such as the repurposing of chemotherapeutic drugs like dasatinib and the prevention of post-ablation BE recurrence using itraconazole, are discussed.
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- 2023
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282. Metabolic disruption impacts tick fitness and microbial relationships.
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Samaddar S, O'Neal AJ, Marnin L, Rolandelli A, Singh N, Wang X, Butler LR, Rangghran P, Laukaitis HJ, Cabrera Paz FE, Fiskum GM, Polster BM, and Pedra JHF
- Abstract
Arthropod-borne microbes rely on the metabolic state of a host to cycle between evolutionarily distant species. For instance, arthropod tolerance to infection may be due to redistribution of metabolic resources, often leading to microbial transmission to mammals. Conversely, metabolic alterations aids in pathogen elimination in humans, who do not ordinarily harbor arthropod-borne microbes. To ascertain the effect of metabolism on interspecies relationships, we engineered a system to evaluate glycolysis and oxidative phosphorylation in the tick Ixodes scapularis . Using a metabolic flux assay, we determined that the rickettsial bacterium Anaplasma phagocytophilum and the Lyme disease spirochete Borrelia burgdorferi , which are transstadially transmitted in nature, induced glycolysis in ticks. On the other hand, the endosymbiont Rickettsia buchneri, which is transovarially maintained, had a minimal effect on I. scapularis bioenergetics. Importantly, the metabolite β-aminoisobutyric acid (BAIBA) was elevated during A. phagocytophilum infection of tick cells following an unbiased metabolomics approach. Thus, we manipulated the expression of genes associated with the catabolism and anabolism of BAIBA in I. scapularis and detected impaired feeding on mammals, reduced bacterial acquisition, and decreased tick survival. Collectively, we reveal the importance of metabolism for tick-microbe relationships and unveil a valuable metabolite for I. scapularis fitness.
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- 2023
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283. Using Open Neuroscience to Advance Equity in the Pedagogy and Research Infrastructure in Colleges/Universities Still Financially Impacted by COVID-19: The Emergence of a Global Resource Network Aimed at Integrating Neuroscience and Society.
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Chagas AM, Canli T, Ziadlou D, Forlano PM, Samaddar S, Chua E, Baskerville KA, Poon K, and Neuwirth LS
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- 2023
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284. Croquemort elicits activation of the immune deficiency pathway in ticks.
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O'Neal AJ, Singh N, Rolandelli A, Laukaitis HJ, Wang X, Shaw DK, Young BD, Narasimhan S, Dutta S, Snyder GA, Samaddar S, Marnin L, Butler LR, Mendes MT, Cabrera Paz FE, Valencia LM, Sundberg EJ, Fikrig E, Pal U, Weber DJ, and Pedra JHF
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- Animals, NF-kappa B, Ixodes microbiology, Borrelia burgdorferi genetics, Arthropods, Bacterial Infections, Lyme Disease microbiology
- Abstract
The immune deficiency (IMD) pathway directs host defense in arthropods upon bacterial infection. In Pancrustacea, peptidoglycan recognition proteins sense microbial moieties and initiate nuclear factor-κB-driven immune responses. Proteins that elicit the IMD pathway in non-insect arthropods remain elusive. Here, we show that an Ixodes scapularis homolog of croquemort (Crq), a CD36-like protein, promotes activation of the tick IMD pathway. Crq exhibits plasma membrane localization and binds the lipid agonist 1-palmitoyl-2-oleoyl- sn -glycero-3-phosphoglycerol. Crq regulates the IMD and jun N-terminal kinase signaling cascades and limits the acquisition of the Lyme disease spirochete B. burgdorferi . Additionally, nymphs silenced for crq display impaired feeding and delayed molting to adulthood due to a deficiency in ecdysteroid synthesis. Collectively, we establish a distinct mechanism for arthropod immunity outside of insects and crustaceans.
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- 2023
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285. Involvement of the Streptococcus mutans PgfE and GalE 4-epimerases in protein glycosylation, carbon metabolism, and cell division.
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Andresen S, de Mojana di Cologna N, Archer-Hartmann S, Rogers AM, Samaddar S, Ganguly T, Black IM, Glushka J, Ng KKS, Azadi P, Lemos JA, Abranches J, and Szymanski CM
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- Humans, Glycosylation, Streptococcus mutans genetics, Streptococcus mutans metabolism, Bacterial Adhesion physiology, Racemases and Epimerases genetics, Racemases and Epimerases metabolism, Endothelial Cells metabolism, Carrier Proteins genetics, Collagen genetics, Cell Division, Adhesins, Bacterial genetics, Dental Caries
- Abstract
Streptococcus mutans is a key pathogen associated with dental caries and is often implicated in infective endocarditis. This organism forms robust biofilms on tooth surfaces and can use collagen-binding proteins (CBPs) to efficiently colonize collagenous substrates, including dentin and heart valves. One of the best characterized CBPs of S. mutans is Cnm, which contributes to adhesion and invasion of oral epithelial and heart endothelial cells. These virulence properties were subsequently linked to post-translational modification (PTM) of the Cnm threonine-rich repeat region by the Pgf glycosylation machinery, which consists of 4 enzymes: PgfS, PgfM1, PgfE, and PgfM2. Inactivation of the S. mutans pgf genes leads to decreased collagen binding, reduced invasion of human coronary artery endothelial cells, and attenuated virulence in the Galleria mellonella invertebrate model. The present study aimed to better understand Cnm glycosylation and characterize the predicted 4-epimerase, PgfE. Using a truncated Cnm variant containing only 2 threonine-rich repeats, mass spectrometric analysis revealed extensive glycosylation with HexNAc2. Compositional analysis, complemented with lectin blotting, identified the HexNAc2 moieties as GlcNAc and GalNAc. Comparison of PgfE with the other S. mutans 4-epimerase GalE through structural modeling, nuclear magnetic resonance, and capillary electrophoresis demonstrated that GalE is a UDP-Glc-4-epimerase, while PgfE is a GlcNAc-4-epimerase. While PgfE exclusively participates in protein O-glycosylation, we found that GalE affects galactose metabolism and cell division. This study further emphasizes the importance of O-linked protein glycosylation and carbohydrate metabolism in S. mutans and identifies the PTM modifications of the key CBP, Cnm., (© The Author(s) 2023. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
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- 2023
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286. Vaccination-Based Immunoprevention of Colorectal Tumors: A Primer for the Clinician.
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Jackson K, Samaddar S, Markiewicz MA, and Bansal A
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- Humans, Immunotherapy, Immunosuppressive Agents, Vaccination, Cancer Vaccines therapeutic use, Colorectal Neoplasms prevention & control
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Colorectal cancer (CRC) continues to be a significant public health problem worldwide. CRC screening programs have reduced the incidence rates of CRCs but still suffer from the problems of missed lesions and interval cancers. Chemopreventive strategies against CRC would benefit high-risk populations but trials testing synthetic and naturally occurring compounds have not yielded a front runner. Immune mechanisms promoting cancer have been modulated to develop immunotherapy for cancer treatment that has revolutionized cancer management, but could also be applied to cancer interception, that is, cancer immunoprevention. Cancer immunoprevention refers to approaches that can enhance the immune system, either directly or by removing natural breaks such as immune checkpoints, to survey and destroy tumor cells. In this primer, we aim to explain the concepts behind vaccine-based cancer immunoprevention. Multiple cancer vaccines have been tried in advanced cancer populations, but most have failed primarily because of an immunosuppressive environment that accompanies advanced cancers. Preventive vaccines in immunocompetent hosts may have a better clinical response compared with therapeutic vaccines in immunosuppressed hosts. The first randomized controlled trial testing the mucin1 vaccine against CRC in the prevention setting has been successfully completed. For the benefit of the clinician, we briefly discuss important concepts related to the workings of preventive vaccines. Prevention with vaccines is a highly attractive approach because of the potential for highly targeted therapy with minimal side effects that could theoretically provide lifelong protection., (Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc.)
- Published
- 2023
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287. The Promising Therapeutic Potential of Oligonucleotides for Pulmonary Fibrotic Diseases.
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Paul D, Miller MH, Born J, Samaddar S, Ni H, Avila H, Krishnamurthy VR, and Thirunavukkarasu K
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- Humans, Powders metabolism, Powders pharmacology, Lung metabolism, Fibrosis, Oligonucleotides adverse effects, Lung Diseases
- Abstract
Introduction: Fibrotic lung diseases represent a large subset of diseases with an unmet clinical need. Oligonucleotide therapies (ONT) are a promising therapeutic approach for the treatment of pulmonary disease as they can inhibit pathways that are otherwise difficult to target. Additionally, targeting the lung specifically with ONT is advantageous because it reduces the possibilities of systemic side effects and tolerability concerns., Areas Covered: This review presents the chemical basis of designing various ONTs currently known to treat fibrotic lung diseases. Further, the authors have also discussed the delivery vehicle, routes of administration, physiological barriers of the lung, and toxicity concerns with ONTs., Expert Opinion: ONTs provide a promising therapeutic approach for the treatment of fibrotic diseases of the lung, particularly because ONTs directly delivered to the lung show little systemic side effects compared to current therapeutic strategies. Dry powder aerosolized inhalers may be a good strategy for getting ONTs into the lung in humans. However, as of now, no dry powder ONTs have been approved for use in the clinical setting, and this challenge must be overcome for future therapies. Various delivery methods that can aid in direct targeting may also improve the use of ONTs for lung fibrotic diseases.
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- 2023
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288. Structure-function relationships of cholesterol mobilization from the endo-lysosome compartment of NPC1-deficient human cells by β-CD polyrotaxanes.
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Samaddar S, Bose D, Loren BP, Skulsky JL, Ilnytska O, Struzik ZJ, Storch J, and Thompson DH
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- Humans, 2-Hydroxypropyl-beta-cyclodextrin pharmacology, 2-Hydroxypropyl-beta-cyclodextrin therapeutic use, Cholesterol metabolism, Lysosomes metabolism, Structure-Activity Relationship, Niemann-Pick C1 Protein, Rotaxanes chemistry, Rotaxanes metabolism, Rotaxanes therapeutic use, Niemann-Pick Disease, Type C metabolism
- Abstract
Niemann-Pick Type C is a rare metabolic disorder characterized by the cellular accumulation of cholesterol within endosomal and lysosomal compartments. 2-Hydroxypropyl-β-cyclodextrin (HP-β-CD) containing polyrotaxanes represent an attractive approach for treating this disease due to their ability to circulate in the blood stream for longer periods of time as a prodrug form of HP-β-CD. Once inside the cell, the macromolecular structure is thought to break down into the Pluronic precursor and the active cyclodextrin agent that promotes cholesterol mobilization from the aberrant accumulations within NPC-deficient cells. We now report that both cholesterol and decaarginine (R10) endcapped polyrotaxanes are able to remove cholesterol from NPC1 patient fibroblasts. R10 endcapped materials enter these cells and are localized within endosomes after 16 h. The cholesterol mobilization from endo-lysosomal compartments of NPC1 cells by the polyrotaxanes was directly related to their extent of endcapping and their threading efficiency. Incorporation of 4-sulfobutylether-β-cyclodextrin (SBE-β-CD) significantly improved cholesterol mobilization due to the improved solubility of the compounds. Additionally, in our efforts to scale-up the synthesis for preclinical studies, we prepared a library of polyrotaxanes using a solid phase synthesis method. These compounds also led to significant cholesterol mobilization from the cells, however, cytotoxicity studies showed that they were substantially more toxic than those prepared by the solvent-assisted method, thus limiting the therapeutic utility of agents prepared by this expedited method. Our findings demonstrate that complete endcapping of the polyrotaxanes and improved solubility are important design features for delivering high copy numbers of therapeutic β-CD to promote enhanced sterol clearance in human NPC1-deficient cells., Competing Interests: DT is a founder of Jewell Laboratories. All other authors have no financial conflicts of interest. This does not alter our adherence to PLOS ONE policies on sharing data and materials.” No further modifications have been made since the conditions for publication appear to be met., (Copyright: © 2022 Samaddar et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
- Published
- 2022
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289. Widening community participation in preparing for climate-related disasters in Japan.
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Kitagawa K and Samaddar S
- Abstract
This paper discusses community participation drawing on ongoing disaster recovery and preparedness projects (RPP) in the communities affected by the Heavy Rain Event of 2018 in western Japan. Participatory approaches have become a mainstream methodology for community-based disaster risk reduction (DRR) as advocated in the Sendai Framework for Disaster Risk Reduction 2015-2030. The majority of participation research addresses either 'success' factors for participation or the types of participation. The paper proposes a notion of 'widening participation' in addressing the challenge of attracting people to participate in preparedness initiatives. Originally widening participation was a higher education policy in the UK aiming to broaden the demographic composition of the student base. Even the RPP that are publicly recognised as 'good practices' struggle to recruit more people for the projects. Borrowing the notion of widening participation, the paper identifies how each project encourages non-participants to get involved in the project activities. The paper applies the EAST framework (Easy, Attractive, Social, Timely) widely utilised in the policy making of widening participation and further public services. Rather than providing the public with information and guidance, 'easy', 'attractive', 'social' and 'timely' behavioural approaches tend to enable participation. Examining these four principles in the four cases of RPP, the paper suggests that the EAST framework is feasible in strengthening the strategies for widening participation in preparedness action. The paper, however, recognises a need to address the difference between top-down public policies and bottom-up community projects in the application of the framework., Competing Interests: Research ethics statementThe authors declare that research ethics approval for this article was provided by IOE (Institute of Education), UCL’s Faculty of Education and Society (University College London, UK) Ethics Committee.Consent for publication statementThe authors declare that research participants’ informed consent to publication of findings – including photos, videos and any personal or identifiable information – was secured prior to publication.Conflicts of interest statementThe authors declare no conflicts of interest with this work.The authors declare no conflicts of interest with this work., (© 2022 The Authors.)
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- 2022
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290. An Epidemiological Study of Hearing Loss in a Peripheral Tertiary Care Hospital.
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Maiti AB, Samaddar S, Ghosh S, Mondal B, Sahu S, and Modak D
- Abstract
The estimated prevalence of adult onset hearing deafness in India is 7.6% and childhood onset hearing loss is 2%. But there are very few studies which highlight the prevalence of various types of hearing loss. So a retrospective, cross-sectional study in a peripheral tertiary care hospital was designed to analyze the different types of hearing loss among patients with complaints of hearing disabilities attending and assess the more prevalent type of hearing loss according to severity. Out of total study population of 14,365 patients, Male patients with Mild hearing loss have the maximum correlation coefficient followed by Moderate, Moderately severe, Profound and Severe hearing loss. In the case of female patients Mild Hearing loss has the maximum correlation coefficient. Result of this study may be helpful in planning and management of different programs related to hearing disability prevention. As most of the hearing loss is mild variety and it slowly progress to other form of severe hearing loss, early intervention is very helpful in reducing the severity thus disability., Competing Interests: Conflict of interestAll authors declare that there is no conflict of interest., (© Association of Otolaryngologists of India 2021.)
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- 2022
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291. Exploring the art of medical photography - an otolaryngologist's perspective.
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Samaddar S, Maiti A, Samaddar S, Mondal B, and Bandyopadhyay S
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- Humans, Photography, Smartphone, Documentation methods, Artificial Intelligence, Otolaryngologists
- Abstract
Background: Modern day otolaryngology has expanded beyond the ear, nose and throat to include head and neck surgery and aesthetic facial procedures. Photographic documentation is important within this expanded horizon. The spectrum of clinical photography includes photomicrographs, endoscopic photographs, peri-operative photography and medical social photography., Method: This article aimed to review the standard guidelines essential to obtain, store and disseminate photographs and looked at setting up a small clinic with minimal gadgets to suit clinical photography requirements. Elaboration of basic photography techniques in otolaryngology was reviewed, with examples of photographs taken in a clinic by a clinician. Advances and innovation in clinical photography, in the form of smartphone photography, artificial intelligence, device editing and newer hardware and software in otorhinolaryngology was reviewed., Conclusion: Having a professional photographer to aid a clinician is a luxury. Simple knowledge and regular practice of basic photography guidelines by a clinician is imperative.
- Published
- 2022
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292. Vitexin alters Staphylococcus aureus surface hydrophobicity to obstruct biofilm formation.
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Das MC, Samaddar S, Jawed JJ, Ghosh C, Acharjee S, Sandhu P, Das A, Daware AV, De UC, Majumdar S, Das Gupta SK, Akhter Y, and Bhattacharjee S
- Subjects
- Animals, Anti-Bacterial Agents pharmacology, Apigenin, Azithromycin pharmacology, Biofilms, Gentamicins pharmacology, Hydrophobic and Hydrophilic Interactions, Mice, Microbial Sensitivity Tests, Staphylococcal Infections microbiology, Staphylococcus aureus
- Abstract
Cell Surface hydrophobicity is one of the determinant biophysical parameters of bacterial aggregation for being networked to form a biofilm. Phytoconstituent, like vitexin, has long been in use for their antibacterial effect. The present work demonstrates the role of vitexin in modulating Staphylococcus aureus surface hydrophobicity while aggregating to form biofilm and pathogenesis in a host. In planktonic form, vitexin shows minimum inhibitory concentration at 252 µg/ml against S. aureus. Sub-MIC doses of vitexin and antibiotics (26 µg/ml of vitexin, 55 µg/ml of azithromycin, and 2.5 µg/ml of gentamicin) were selected to treat S. aureus. Dead cell counts after treatment were studied through flow cytometry. As dead cell counts were minimal (<5 %), these doses were considered for all subsequent experiments. While studying aggregating cells, it was observed that vitexin reduces S. aureus surface hydrophobicity and membrane permeability at the sub-MIC dose of 26 µg/ml. The in silico binding analysis showed a higher binding affinity of vitexin with surface proteins (IcaA, DltA, and SasG) of S. aureus. Down-regulation of dltA and icaAB expression, along with the reduction in membrane potential with a sub-MIC dose of vitexin, explains reduced S. aureus surface hydrophobicity. Vitexin was found to interfere with S. aureus biofilm-associated protein biomass, EPS production, and swarming movement. Subsequently, the suppression of proteases production and down-regulation of icaAB and agrAC gene expression with a sub-MIC dose of vitexin explained the inhibition of S. aureus virulence in vitro. Besides, vitexin was also found to potentiate the antibiofilm activity of sub-MIC doses of gentamicin and azithromycin. Treatment with vitexin exhibits a protective response in S. aureus infected macrophages through modulation of expression of cytokines like IL-10 and IL-12p40 at protein and mRNA levels. Furthermore, CFU count and histological examination of infected mouse tissue (liver and spleen) justify the in vivo protective effect of vitexin from S. aureus biofilm-associated infection. From this study, it can be inferred that vitexin can reduce S. aureus surface hydrophobicity, leading to interference with aggregation at the time of biofilm formation and subsequent pathogenesis in a host., (Copyright © 2022 Elsevier GmbH. All rights reserved.)
- Published
- 2022
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293. A Retrospective Comparative Study on the Outcome of Microscope-Assisted Technique and Supra-Auricular Approach in Preauricular Sinus Surgery in a Tertiary Care Hospital.
- Author
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Maiti AB, Dam SP, Samaddar S, and Das SK
- Abstract
Context: Preauricular sinus (PAS) can lead to severe complications such as facial paralysis, and squamous cell carcinoma may develop from this sinus later in life. Asymptomatic sinus needs no intervention, but symptomatic sinus needs surgical interventions., Aims: This study compares the surgical outcome of microscope-assisted sinus tract excision technique with the supra-auricular sinectomy technique., Settings and Design: This was a retrospective, observational study conducted at a tertiary care hospital in Purulia District, West Bengal, India., Subjects and Methods: Records of patients operated on for PAS were included following the proper inclusion and exclusion criteria. These patients were categorized and followed up based on disease pathology and the type of intervention received., Statistical Analysis Used: Data were collected, tabulated, and analyzed using the standard statistical software., Results: Fifty-two patients were included in our study. About 48.07% of patients were found in the age group of 11-15 years. In the microscope-assisted sinectomy category, recurrence of the disease was seen in 2 out of 15 operated patients compared to 1 patient among 13 in the supra-auricular sinectomy approach for uncomplicated cases. In complicated cases, the supra-auricular sinectomy approach had a nil recurrence rate compared to three patients out of ten operated in microscope-assisted technique (Fisher's exact test - 0.0593). Both the outcomes are not statistically significant., Conclusion: Supra-auricular sinectomy technique has the lowest recurrence rate for preauricular sinus surgery., Competing Interests: There are no conflicts of interest., (Copyright: © 2022 Journal of Indian Association of Pediatric Surgeons.)
- Published
- 2022
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294. Addition to "Evidence for Local Spots of Viscous Electron Flow in Graphene at Moderate Mobility".
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Samaddar S, Strasdas J, Janßen K, Just S, Johnsen T, Wang Z, Uzlu B, Li S, Neumaier D, Liebmann M, and Morgenstern M
- Published
- 2022
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295. The G Protein-Coupled Serotonin 1A Receptor Augments Protein Kinase Cε-Mediated Neurogenesis in Neonatal Mouse Hippocampus-PKCε-Mediated Signaling in the Early Hippocampus.
- Author
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Samaddar S, Purkayastha S, Diallo S, Tantry SJ, Schroder R, Chanthrakumar P, Flory MJ, and Banerjee P
- Subjects
- 8-Hydroxy-2-(di-n-propylamino)tetralin pharmacology, Animals, Animals, Newborn, Apoptosis drug effects, Bromodeoxyuridine pharmacology, Dentate Gyrus drug effects, Dentate Gyrus metabolism, Dentate Gyrus physiology, Female, Hippocampus drug effects, Hippocampus physiology, Male, Mice, Mice, Inbred C57BL, Neurogenesis drug effects, Neurons drug effects, Neurons metabolism, Neurons physiology, Serotonin Receptor Agonists pharmacology, Signal Transduction drug effects, Hippocampus metabolism, Neurogenesis physiology, Protein Kinase C-epsilon metabolism, Receptor, Serotonin, 5-HT1A metabolism, Receptors, G-Protein-Coupled metabolism, Serotonin metabolism, Signal Transduction physiology
- Abstract
The neurotransmitter serotonin (5-HT) plays an important role in mood disorders. It has been demonstrated that 5-HT signaling through 5-HT
1A receptors (5-HT1A -R) is crucial for early postnatal hippocampal development and later-life behavior. Although this suggests that 5-HT1A -R signaling regulates early brain development, the mechanistic underpinnings of this process have remained unclear. Here we show that stimulation of the 5-HT1A -R at postnatal day 6 (P6) by intrahippocampal infusion of the agonist 8-OH-DPAT (D) causes signaling through protein kinase Cε (PKCε) and extracellular receptor activated kinase ½ (ERK1/2) to boost neuroblast proliferation in the dentate gyrus (DG), as displayed by an increase in bromodeoxy-uridine (BrdU), doublecortin (DCX) double-positive cells. This boost in neuroproliferation was eliminated in mice treated with D in the presence of a 5-HT1A -R antagonist (WAY100635), a selective PKCε inhibitor, or an ERK1/2-kinase (MEK) inhibitor (U0126). It is believed that hippocampal neuro-progenitors undergoing neonatal proliferation subsequently become postmitotic and enter the synaptogenesis phase. Double-staining with antibodies against bromodeoxyuridine (BrdU) and neuronal nuclear protein (NeuN) confirmed that 5-HT1A -R → PKCε → ERK1/2-mediated boosted neuroproliferation at P6 also leads to an increase in BrdU-labeled granular neurons at P36. This 5-HT1A -R-mediated increase in mature neurons was unlikely due to suppressed apoptosis, because terminal deoxynucleotidyl transferase dUTP nick-end labeling analysis showed no difference in DNA terminal labeling between vehicle and 8-OH-DPAT-infused mice. Therefore, 5-HT1A -R signaling through PKCε may play an important role in micro-neurogenesis in the DG at P6, following which many of these new-born neuroprogenitors develop into mature neurons.- Published
- 2022
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296. A silent giant staghorn renal calculus managed successfully with open pyelolithotomy: a case report.
- Author
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Kesharwani D, Samaddar S, Ghose A, and Omorphos NP
- Abstract
Staghorn calculi (SC) are associated with high morbidity and mortality; therefore, meticulous planning is required to minimize complications. In this case report, we will discuss the management of a giant right-sided SC (~ 8 cm in diameter), which was incidentally found in a 40-year-old male, who presented with left-sided renal colic symptoms with no associated renal impairment. This case was further complicated by multiple smaller calculi surrounding the giant SC. Hence, open surgery was preferred to minimally invasive techniques. The patient underwent an uncomplicated right-sided open pyelolithotomy for his staghorn calculus and was calculi free at 1-month follow-up. His renal function returned to normal levels, highlighting effective management of the stones., (Published by Oxford University Press and JSCR Publishing Ltd. All rights reserved. © The Author(s) 2022.)
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- 2022
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297. Evidence for Local Spots of Viscous Electron Flow in Graphene at Moderate Mobility.
- Author
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Samaddar S, Strasdas J, Janßen K, Just S, Johnsen T, Wang Z, Uzlu B, Li S, Neumaier D, Liebmann M, and Morgenstern M
- Abstract
Dominating electron-electron scattering enables viscous electron flow exhibiting hydrodynamic current density patterns, such as Poiseuille profiles or vortices. The viscous regime has recently been observed in graphene by nonlocal transport experiments and mapping of the Poiseuille profile. Herein, we probe the current-induced surface potential maps of graphene field-effect transistors with moderate mobility using scanning probe microscopy at room temperature. We discover micrometer-sized large areas appearing close to charge neutrality that show current-induced electric fields opposing the externally applied field. By estimating the local scattering lengths from the gate dependence of local in-plane electric fields, we find that electron-electron scattering dominates in these areas as expected for viscous flow. Moreover, we suppress the inverted fields by artificially decreasing the electron-disorder scattering length via mild ion bombardment. These results imply that viscous electron flow is omnipresent in graphene devices, even at moderate mobility.
- Published
- 2021
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298. Homeostatic scaling is driven by a translation-dependent degradation axis that recruits miRISC remodeling.
- Author
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Srinivasan B, Samaddar S, Mylavarapu SVS, Clement JP, and Banerjee S
- Subjects
- Animals, Cytoskeletal Proteins metabolism, Mechanistic Target of Rapamycin Complex 1 metabolism, MicroRNAs genetics, Nerve Tissue Proteins metabolism, Neurons metabolism, Phosphorylation, Polyribosomes metabolism, Polyubiquitin metabolism, Proteasome Endopeptidase Complex metabolism, Rats, Sprague-Dawley, Receptors, AMPA metabolism, Ribosomal Protein S6 Kinases, 70-kDa metabolism, Synapses metabolism, Transcription Factors metabolism, Tripartite Motif Proteins metabolism, Ubiquitin-Protein Ligases metabolism, Ubiquitination, Rats, Homeostasis genetics, MicroRNAs metabolism, Protein Biosynthesis genetics, Proteolysis, RNA-Induced Silencing Complex metabolism
- Abstract
Homeostatic scaling in neurons has been attributed to the individual contribution of either translation or degradation; however, there remains limited insight toward understanding how the interplay between the two processes effectuates synaptic homeostasis. Here, we report that a codependence between protein synthesis and degradation mechanisms drives synaptic homeostasis, whereas abrogation of either prevents it. Coordination between the two processes is achieved through the formation of a tripartite complex between translation regulators, the 26S proteasome, and the miRNA-induced silencing complex (miRISC) components such as Argonaute, MOV10, and Trim32 on actively translating transcripts or polysomes. The components of this ternary complex directly interact with each other in an RNA-dependent manner. Disruption of polysomes abolishes this ternary interaction, suggesting that translating RNAs facilitate the combinatorial action of the proteasome and the translational apparatus. We identify that synaptic downscaling involves miRISC remodeling, which entails the mTORC1-dependent translation of Trim32, an E3 ligase, and the subsequent degradation of its target, MOV10 via the phosphorylation of p70 S6 kinase. We find that the E3 ligase Trim32 specifically polyubiquitinates MOV10 for its degradation during synaptic downscaling. MOV10 degradation alone is sufficient to invoke downscaling by enhancing Arc translation through its 3' UTR and causing the subsequent removal of postsynaptic AMPA receptors. Synaptic scaling was occluded when we depleted Trim32 and overexpressed MOV10 in neurons, suggesting that the Trim32-MOV10 axis is necessary for synaptic downscaling. We propose a mechanism that exploits a translation-driven protein degradation paradigm to invoke miRISC remodeling and induce homeostatic scaling during chronic network activity., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2021
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299. Far from the nuclear crowd: Cytoplasmic lncRNA and their implications in synaptic plasticity and memory.
- Author
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Samaddar S and Banerjee S
- Subjects
- Animals, Cell Nucleus metabolism, Cytoplasm metabolism, Humans, Subcellular Fractions metabolism, Memory physiology, Neuronal Plasticity physiology, RNA, Long Noncoding physiology
- Abstract
A striking proportion of long non-coding RNAs are expressed specifically in the mammalian brain. Advances in genome-wide sequencing detected widespread diversity in neuronal lncRNAs based on their expression pattern, localization and function. A growing body of literature proposes that localization of lncRNAs is a critical determinant of their function. A rising number of recent findings documented distinct cytoplasmic functions of lncRNAs that are linked to activity-induced control of synaptic plasticity. However, the comprehensive role of cytoplasmic lncRNAs in neuronal functions is less understood. This review surveys our current understanding of lncRNAs that regulate the cytoplasmic life of mRNAs. We discuss the necessity of subcellular localization of lncRNAs in neuronal dendrites and the impact of their compartmentalized positioning on localized translation at the synapse. We have highlighted how lncRNAs modify a functional compartment to meet the demand for input-specific control of synaptic plasticity and memory., (Copyright © 2021 Elsevier Inc. All rights reserved.)
- Published
- 2021
- Full Text
- View/download PDF
300. Piecewise Isothermal Nucleic Acid Testing (PINAT) for Infectious Disease Detection with Sample-to-Result Integration at the Point-of-Care.
- Author
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Banerjee S, Biswas SK, Kedia N, Sarkar R, De A, Mitra S, Roy S, Chowdhury R, Samaddar S, Bandopadhyay A, Banerjee I, Jana S, Goswami R, Dutta S, Chawla-Sarkar M, Chakraborty S, and Mondal A
- Subjects
- Humans, Point-of-Care Systems, RNA, Viral genetics, SARS-CoV-2, COVID-19, Communicable Diseases
- Abstract
We developed a piecewise isothermal nucleic acid test (PINAT) as a platform technology for diagnosing pathogen-associated infections, empowered by an illustrative novel methodology that embeds an exclusive DNA-mediated specific probing reaction with the backbone of an isothermal reverse transcription cum amplification protocol for detecting viral RNA. In a point-of-care format, this test is executable in a unified single-step, single-chamber procedure, leading to seamless sample-to-result integration in an inexpensive, scalable, pre-programmable, and customizable portable device, with mobile-app-integrated interpretation and analytics involving minimal manually operative procedures. The test exhibited a high sensitivity and specificity of detection when assessed using 200 double-blind patient samples for detecting SARS-CoV-2 infection by the Indian Council of Medical Research (ICMR), and subsequently using 170 double-blind patient samples in a point-of-care format outside controlled laboratory settings as performed by unskilled technicians in an organized clinical trial. We also established its efficacy in detecting Influenza A infection by performing the diagnosis at the point of collection with uncompromised detection rigor. The envisaged trade-off between advanced laboratory-based molecular diagnostic procedures and the elegance of common rapid tests renders the method ideal for deployment in resource-limited settings towards catering the needs of the underserved.
- Published
- 2021
- Full Text
- View/download PDF
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