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Found 37769 matches. Displaying 1631-1640
Nicolas P, Etoc F, Brivanlou AH
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The ethics of human-embryoids model: a call for consistency

JOURNAL OF MOLECULAR MEDICINE-JMM 2021 APR; 99(4):569-579
In this article, we discuss the ethics of human embryoids, i.e., embryo-like structures made from pluripotent stem cells for modeling natural embryos. We argue that defining our social priorities is critical to design a consistent ethical guideline for research on those new entities. The absence of clear regulations on these emerging technologies stems from an unresolved debate surrounding natural human embryo research and one common opinion that one needs to solve the question of the moral status of the human embryo before regulating their surrogate. The recent NIH funding restrictions for research on human embryoids have made scientists even more unlikely to raise their voices. As a result, the scientific community has maintained a low profile while longing for a more favorable socio-political climate for their research. This article is a call for consistency among biomedical research on human materials, trying to position human embryoids within a spectrum of existing practice from stem cell research or IVF to research involving human subjects. We specifically note that the current practices in infertility clinics of freezing human embryos or disposing of them without any consideration for their potential benefits contradicts the assumption of special consideration for human material. Conversely, creating human embryoids for research purposes could ensure that no human material be used in vain, always serving humankind. We argue here that it is time to reconsider the full ban on embryo research (human embryos and embryoids) beyond the 14-day rule and that research on those entities should obey a sliding scale combining the completeness of the model (e.g., complete vs. partial) and the developmental stage: with more advanced completeness and developmental stage of the considered entity, being associated with more rigorous evaluation of societal benefits, statements of intention, and necessity of such research.
Renert-Yuval Y, Thyssen JP, Bissonnette R, Bieber T, Kabashima K, Hijnen D, Guttman-Yassky E
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Biomarkers in atopic dermatitis-a review on behalf of the International Eczema Council

JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY 2021 APR; 147(4):1174-+
Atopic dermatitis (AD) is a common yet complex skin disease, posing a therapeutic challenge with increasingly recognized different phenotypes among variable patient populations. Because therapeutic response may vary on the basis of heterogeneous clinical and molecular phenotypes, a shift toward precision medicine approaches may improve AD management. Herein, we will consider biomarkers as potential instruments in the toolbox of precision medicine in AD and will review the process of biomarker development and validation, the opinion of AD experts on the use of biomarkers, types of biomarkers, encompassing biomarkers that may improve AD diagnosis, biomarkers reflecting disease severity, and those potentially predicting AD development, concomitant atopic diseases, or therapeutic response, and current practice of biomarkers in AD. We found that chemokine C-C motif ligand 17/thymus and activation-regulated chemokine, a chemoattractant of T(H)2 cells, has currently the greatest evidence for robust correlation with AD clinical severity, at both baseline and during therapy, by using the recommendations, assessment, development, and evaluation approach. Although the potential of biomarkers in AD is yet to be fully elucidated, due to the complexity of the disease, a comprehensive approach taking into account both clinical and reliable, AD-specific biomarker evaluations would further facilitate AD research and improve patient management.
Nesic D, Bush M, Spasic A, Li JH, Kamata T, Handa M, Filizola M, Walz T, Coller BS
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Electron microscopy shows that binding of monoclonal antibody PT25-2 primes integrin alpha IIb beta 3 for ligand binding

BLOOD ADVANCES 2021 APR 13; 5(7):1781-1790
The murine monoclonal antibody (mAb) PT25-2 induces alpha IIb beta 3 to bind ligand and initiate 3 platelet aggregation. The underlying mechanism is unclear, because previous mutagenesis studies suggested that PT25-2 binds to the alpha IIb beta 3 propeller, a site distant from the Arg-Gly-Asp-binding pocket. To elucidate the mechanism, we studied the alpha IIb beta 3-PT25-2 Fab complex by negative-stain and cryo-electron microscopy (EM). We found that PT25-2 binding results in alpha IIb beta 3 partially exposing multiple ligand-induced binding site epitopes and adopting extended conformations without swing-out of the beta 3 hybrid domain. The cryo-EM structure showed PT25-2 binding to the allb residues identified by mutagenesis but also to 2 additional regions. Overlay of the cryo-EM structure with the bent alpha IIb beta 3 crystal structure showed that binding of PT25-2 creates clashes with the alpha IIb calf-1/calf-2 domains, suggesting that PT25-2 selectively binds to partially or fully extended receptor conformations and prevents a return to its bent conformation. Kinetic studies of the binding of PT25-2 compared with mAbs 10E5 and 7E3 support this hypothesis. We conclude that PT25-2 induces alpha IIb beta 3 ligand binding by binding to extended conformations and by preventing the interactions between the alpha IIb and beta 3 leg domains and subsequently the beta I and beta 3 leg domains required for the bent-closed conformation.
Wang ZJ, Schmidt F, Weisblum Y, Muecksch F, Barnes CO, Finkin S, Schaefer-Babajew D, Cipolla M, Gaebler C, Lieberman JA, Oliveira TY, Yang Z, Abernathy ME, Huey-Tubman KE, Hurley A, Turroja M, West KA, Gordon K, Millard KG, Ramos V, Da Silva J, Xu JL, Colbert RA, Patel R, Dizon J, Unson-O'Brien C, Shimeliovich I, Gazumyan A, Caskey M, Bjorkman PJ, Casellas R, Hatziioannou T, Bieniasz PD, Nussenzweig MC
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mRNA vaccine-elicited antibodies to SARS-CoV-2 and circulating variants

NATURE 2021 APR 22; 592(7855):616-622
Here we report on the antibody and memory B cell responses of a cohort of 20 volunteers who received the Moderna (mRNA-1273) or Pfizer-BioNTech (BNT162b2) vaccine against SARS-CoV-2(1-4). Eight weeks after the second injection of vaccine, volunteers showed high levels of IgM and IgG anti-SARS-CoV-2 spike protein (S) and receptor-binding-domain (RBD) binding titre. Moreover, the plasma neutralizing activity and relative numbers of RBD-specific memory B cells of vaccinated volunteers were equivalent to those of individuals who had recovered from natural infection(5,6). However, activity against SARS-CoV-2 variants that encode E484K-, N501Y- or K417N/E484K/N501-mutant S was reduced by a small-but significant-margin. The monoclonal antibodies elicited by the vaccines potently neutralize SARS-CoV-2, and target a number of different RBD epitopes in common with monoclonal antibodies isolated from infected donors(5-8). However, neutralization by 14 of the 17 most-potent monoclonal antibodies that we tested was reduced or abolished by the K417N, E484K or N501Y mutation. Notably, these mutations were selected when we cultured recombinant vesicular stomatitis virus expressing SARS-CoV-2 S in the presence of the monoclonal antibodies elicited by the vaccines. Together, these results suggest that the monoclonal antibodies in clinical use should be tested against newly arising variants, and that mRNA vaccines may need to be updated periodically to avoid a potential loss of clinical efficacy.
de Jong YP, Herzog RW
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Y Liver gene therapy and hepatocellular carcinoma: A complex web

MOLECULAR THERAPY 2021 APR 7; 29(4):1353-1354
Hwang JY, Nawaz S, Choi J, Wang HF, Hussain S, Nawaz M, Lopez-Giraldez F, Jeong K, Dong WL, Oh JN, Bilguvar K, Mane S, Lee CK, Bystroff C, Lifton RP, Ahmad W, Chung JJ
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Genetic Defects in DNAH2 Underlie Male Infertility With Multiple Morphological Abnormalities of the Sperm Flagella in Humans and Mice

FRONTIERS IN CELL AND DEVELOPMENTAL BIOLOGY 2021 APR 23; 9(?):? Article 662903
Asthenozoospermia accounts for over 80% of primary male infertility cases. Reduced sperm motility in asthenozoospermic patients are often accompanied by teratozoospermia, or defective sperm morphology, with varying severity. Multiple morphological abnormalities of the flagella (MMAF) is one of the most severe forms of asthenoteratozoospermia, characterized by heterogeneous flagellar abnormalities. Among various genetic factors known to cause MMAF, multiple variants in the DNAH2 gene are reported to underlie MMAF in humans. However, the pathogenicity by DNAH2 mutations remains largely unknown. In this study, we identified a novel recessive variant (NM_020877:c.12720G > T;p.W4240C) in DNAH2 by whole-exome sequencing, which fully co-segregated with the infertile male members in a consanguineous Pakistani family diagnosed with asthenozoospermia. 80-90% of the sperm from the patients are morphologically abnormal, and in silico analysis models reveal that the non-synonymous variant substitutes a residue in dynein heavy chain domain and destabilizes DNAH2. To better understand the pathogenicity of various DNAH2 variants underlying MMAF in general, we functionally characterized Dnah2-mutant mice generated by CRISPR/Cas9 genome editing. Dnah2-null males, but not females, are infertile. Dnah2-null sperm cells display absent, short, bent, coiled, and/or irregular flagella consistent with the MMAF phenotype. We found misexpression of centriolar proteins and delocalization of annulus proteins in Dnah2-null spermatids and sperm, suggesting dysregulated flagella development in spermiogenesis. Scanning and transmission electron microscopy analyses revealed that flagella ultrastructure is severely disorganized in Dnah2-null sperm. Absence of DNAH2 compromises the expression of other axonemal components such as DNAH1 and RSPH3. Our results demonstrate that DNAH2 is essential for multiple steps in sperm flagella formation and provide insights into molecular and cellular mechanisms of MMAF pathogenesis.
Theofanopoulou C, Gedman G, Cahill JA, Boeckx C, Jarvis ED
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Universal nomenclature for oxytocin-vasotocin ligand and receptor families

NATURE 2021 APR 29; 592(7856):747-755
Oxytocin (OXT; hereafter OT) and arginine vasopressin or vasotocin (AVP or VT; hereafter VT) are neurotransmitter ligands that function through specific receptors to control diverse functions(1,2). Here we performed genomic analyses on 35 species that span all major vertebrate lineages, including newly generated high-contiguity assemblies from the Vertebrate Genomes Project(3,4). Our findings support the claim(5) that OT (also known as OXT) and VT (also known as AVP) are adjacent paralogous genes that have resulted from a local duplication, which we infer was through DNA transposable elements near the origin of vertebrates and in which VT retained more of the parental sequence. We identified six major oxytocin-vasotocin receptors among vertebrates. We propose that all six of these receptors arose from a single receptor that was shared with the common ancestor of invertebrates, through a combination of whole-genome and large segmental duplications. We propose a universal nomenclature based on evolutionary relationships for the genes that encode these receptors, in which the genes are given the same orthologous names across vertebrates and paralogous names relative to each other. This nomenclature avoids confusion due to differential naming in the pre-genomic era and incomplete genome assemblies, furthers our understanding of the evolution of these genes, aids in the translation of findings across species and serves as a model for other gene families. A revised, universal nomenclature for the vertebrate genes that encode the oxytocin and vasopressin-vasotocin ligands and receptors will improve our understanding of gene evolution and facilitate the translation of findings across species.
Pae J, Ersching J, Castro TBR, Schips M, Mesin L, Allon SJ, Ordovas-Montanes J, Mlynarczyk C, Melnick A, Efeyan A, Shalek AK, Meyer-Hermann M, Victora GD
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Cyclin D3 drives inertial cell cycling in dark zone germinal center B cells

JOURNAL OF EXPERIMENTAL MEDICINE 2021 APR 5; 218(4):? Article e20201699
During affinity maturation, germinal center (GC) B cells alternate between proliferation and somatic hypermutation in the dark zone (DZ) and affinity-dependent selection in the light zone (LZ). This anatomical segregation imposes that the vigorous proliferation that allows clonal expansion of positively selected GC B cells takes place ostensibly in the absence of the signals that triggered selection in the LZ, as if by "inertia." We find that such inertial cycles specifically require the cell cycle regulator cyclin D3. Cyclin D3 dose-dependently controls the extent to which B cells proliferate in the DZ and is essential for effective clonal expansion of GC B cells in response to strong T follicular helper (Tfh) cell help. Introduction into the Ccnd3 gene of a Burkitt lymphoma?associated gain-of-function mutation (T283A) leads to larger GCs with increased DZ proliferation and, in older mice, clonal B cell lymphoproliferation, suggesting that the DZ inertial cell cycle program can be coopted by B cells undergoing malignant transformation.
Fins JJ
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Resuscitating Patient Rights during the Pandemic: COVID-19 and the Risk of Resurgent Paternalism

CAMBRIDGE QUARTERLY OF HEALTHCARE ETHICS 2021 APR; 30(2):215-221 Article PII S0963180120000535
The COVID-19 Pandemic a stress test for clinical medicine and medical ethics, with a confluence over questions of the proportionality of resuscitation. Drawing upon his experience as a clinical ethicist during the surge in New York City during the Spring of 2020, the author considers how attitudes regarding resuscitation have evolved since the inception of do-not-resuscitate (DNR) orders decades ago. Sharing a personal narrative about a DNR quandry he encountered as a medical intern, the author considers the balance of patient rights versus clinical discretion, warning about the risk of resurgent physician paternalism dressed up in the guise of a public health crisis.
Voyer TL, Neehus AL, Yang R, Ogishi M, Rosain J, Alroqi F, Alshalan M, Blumental S, Al Ali F, Khan T, Ata M, Rozen L, Demulder A, Bastard P, Gruber C, Roynard M, Seeleuthener Y, Rapaport F, Bigio B, Chrabieh M, Sng D, Berteloot L, Boddaert N, Rozenberg F, Al-Muhsen S, Bertoli-Avella A, Abel L, Bogunovic D, Marr N, Mansouri D, Al Mutairi F, Beziat V, Weil D, Mahdaviani SA, Ferster A, Zhang SY, Reversade B, Boisson-Dupuis S, Casanova JL, Bustamante J
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Inherited deficiency of stress granule ZNFX1 in patients with monocytosis and mycobacterial disease

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 2021 APR 13; 118(15):? Article e2102804118
Human inborn errors of IFN-gamma underlie mycobacterial disease, due to insufficient IFN-gamma production by lymphoid cells, impaired myeloid cell responses to this cytokine, or both. We report four patients from two unrelated kindreds with intermittent monocytosis and mycobacterial disease, including bacillus Calmette-Guerin-osis and disseminated tuberculosis, and without any known inborn error of IFN-gamma. The patients are homozygous for ZNFX1 variants (p.S959* and p.E1606Rfs*10) predicted to be loss of function (pLOF). There are no subjects homozygous for pLOF variants in public databases. ZNFX1 is a conserved and broadly expressed helicase, but its biology remains largely unknown. It is thought to act as a viral double-stranded RNA sensor in mice, but these patients do not suffer from severe viral illnesses. We analyze its subcellular localization upon overexpression in A549 and HeLa cell lines and upon stimulation of THP1 and fibroblastic cell lines. We find that this cytoplasmic protein can be recruited to or even induce stress granules. The endogenous ZNFX1 protein in cell lines of the patient homozygous for the p.E1606Rfs*10 variant is truncated, whereas ZNFX1 expression is abolished in cell lines from the patients with the p.S959* variant. Lymphocyte subsets are present at normal frequencies in these patients and produce IFN-gamma normally. The hematopoietic and nonhematopoietic cells of the patients tested respond normally to IFN-gamma. Our results indicate that human ZNFX1 is associated with stress granules and essential for both monocyte homeostasis and protective immunity to mycobacteria.