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Found 37684 matches. Displaying 1471-1480
Clark AT, Brivanlou A, Fu JP, Kato K, Mathews D, Niakan KK, Rivron N, Saitou M, Surani A, Tang FC, Rossant J
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Human embryo research, stem cell-derived embryo models and in vitro gametogenesis: Considerations leading to the revised ISSCR guidelines

STEM CELL REPORTS 2021 JUN 8; 16(6):1416-1424
The ISSCR Guidelines for Stem Cell Research and Clinical Translation were last revised in 2016. Since then, rapid progress has been made in research areas related to in vitro culture of human embryos, creation of stem cell-based embryo models, and in vitro gametogenesis. Therefore, a working group of international experts was convened to review the oversight process and provide an update to the guidelines. This report captures the discussion and summarizes the major recommendations made by this working group, with a specific emphasis on updating the categories of review and engagement with the specialized scientific and ethical oversight process.
Ogishi M, Yang R, Aytekin C, Langlais D, Bourgey M, Khan T, Al Ali F, Rahman M, Delmonte OM, Chrabieh M, Zhang P, Gruber C, Pelham SJ, Spaan AN, Rosain J, Lei WT, Drutman S, Hellmann MD, Callahan MK, Adamow M, Wong P, Wolchok JD, Rao G, Ma CS, Nakajima Y, Yaguchi T, Chamoto K, Williams SC, Emile JF, Rozenberg F, Glickman MS, Rapaport F, Kerner G, Allington G, Tezcan I, Cagdas D, Hosnut FO, Dogu F, Ikinciogullari A, Rao VK, Kainulainen L, Beziat V, Bustamante J, Vilarinho S, Lifton RP, Boisson B, Abel L, Bogunovic D, Marr N, Notarangelo LD, Tangye SG, Honjo T, Gros P, Boisson-Dupuis S, Casanova JL
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Inherited PD-1 deficiency underlies tuberculosis and autoimmunity in a child

NATURE MEDICINE 2021; ?(?):?
Dysregulated immune features in a patient with a homozygous loss-of-function mutation in PDCD1 suggest that IL-6, IL-23, STAT3 and ROR gamma T might be potential targets for treatment of PD-1 blockade-induced autoimmunity. The pathophysiology of adverse events following programmed cell death protein 1 (PD-1) blockade, including tuberculosis (TB) and autoimmunity, remains poorly characterized. We studied a patient with inherited PD-1 deficiency and TB who died of pulmonary autoimmunity. The patient's leukocytes did not express PD-1 or respond to PD-1-mediated suppression. The patient's lymphocytes produced only small amounts of interferon (IFN)-gamma upon mycobacterial stimuli, similarly to patients with inborn errors of IFN-gamma production who are vulnerable to TB. This phenotype resulted from a combined depletion of V delta 2(+) gamma delta T, mucosal-associated invariant T and CD56(bright) natural killer lymphocytes and dysfunction of other T lymphocyte subsets. Moreover, the patient displayed hepatosplenomegaly and an expansion of total, activated and ROR gamma T+ CD4(-)CD8(-) double-negative alpha beta T cells, similar to patients with STAT3 gain-of-function mutations who display lymphoproliferative autoimmunity. This phenotype resulted from excessive amounts of STAT3-activating cytokines interleukin (IL)-6 and IL-23 produced by activated T lymphocytes and monocytes, and the STAT3-dependent expression of ROR gamma T by activated T lymphocytes. Our work highlights the indispensable role of human PD-1 in governing both antimycobacterial immunity and self-tolerance, while identifying potentially actionable molecular targets for the diagnostic and therapeutic management of TB and autoimmunity in patients on PD-1 blockade.
Weinberg DN, Rosenbaum P, Chen X, Barrows D, Horth C, Marunde MR, Popova IK, Gillespie ZB, Keogh MC, Lu C, Majewski J, Allis CD
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Two competing mechanisms of DNMT3A recruitment regulate the dynamics of de novo DNA methylation at PRC1-targeted CpG islands

NATURE GENETICS 2021 JUN; 53(6):794-800
Precise deposition of CpG methylation is critical for mammalian development and tissue homeostasis and is often dysregulated in human diseases. The localization of de novo DNA methyltransferase DNMT3A is facilitated by its PWWP domain recognizing histone H3 lysine 36 (H3K36) methylation(1,2) and is normally depleted at CpG islands (CGIs)(3). However, methylation of CGIs regulated by Polycomb repressive complexes (PRCs) has also been observed(4-8). Here, we report that DNMT3A PWWP domain mutations identified in paragangliomas(9) and microcephalic dwarfism(10) promote aberrant localization of DNMT3A to CGIs in a PRC1-dependent manner. DNMT3A PWWP mutants accumulate at regions containing PRC1-mediated formation of monoubiquitylated histone H2A lysine 119 (H2AK119ub), irrespective of the amounts of PRC2-catalyzed formation of trimethylated histone H3 lysine 27 (H3K27me3). DNMT3A interacts with H2AK119ub-modified nucleosomes through a putative amino-terminal ubiquitin-dependent recruitment region, providing an alternative form of DNMT3A genomic targeting that is augmented by the loss of PWWP reader function. Ablation of PRC1 abrogates localization of DNMT3A PWWP mutants to CGIs and prevents aberrant DNA hypermethylation. Our study implies that a balance between DNMT3A recruitment by distinct reader domains guides de novo CpG methylation and may underlie the abnormal DNA methylation landscapes observed in select human cancer subtypes and developmental disorders.
Goodroe A, Wachtman L, Benedict W, Allen-Worthington K, Bakker J, Burns M, Diaz LL, Dick E, Dickerson M, Eliades SJ, Gonzalez O, Graf DJ, Haroush K, Inoue T, Izzi J, Laudano A, Layne-Colon D, Leblanc M, Ludwig B, Mejia A, Miller C, Sarfaty A, Sosa M, Vallender E, Brown C, Forney L, Schultz-Darken N, Colman R, Power M, Capuano S, Ross C, Tardif S
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Current practices in nutrition management and disease incidence of common marmosets (Callithrix jacchus)

JOURNAL OF MEDICAL PRIMATOLOGY 2021 JUN; 50(3):164-175
Background A survey was developed to characterize disease incidence, common pathology lesions, environmental characteristics, and nutrition programs within captive research marmoset colonies. Methods Seventeen research facilities completed the electronic survey. Results Nutritional management programs varied amongst research institutions housing marmosets; eight primary base diets were reported. The most common clinical syndromes reported were gastrointestinal disease (i.e. inflammatory bowel disease like disease, chronic lymphocytic enteritis, chronic malabsorption, chronic diarrhea), metabolic bone disease or fracture, infectious diarrhea, and oral disease (tooth root abscesses, gingivitis, tooth root resorption). The five most common pathology morphologic diagnoses were colitis, nephropathy/nephritis, enteritis, chronic lymphoplasmacytic enteritis, and cholecystitis. Obesity was more common (average 20% of a reporting institution's population) than thin body condition (average 5%). Conclusions Through review of current practices, we aim to inspire development of evidence-based practices to standardize husbandry and nutrition practices for marmoset research colonies.
Nestor PG, Hasler VC, O'Donovan K, Lapp HE, Boodai SB, Hunter R
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Psychiatric risk and resilience: Plasticity genes and positive mental health

BRAIN AND BEHAVIOR 2021 JUN; 11(6):? Article e02137
Objective The at-risk mental state (ARMS) for psychosis has long played a key role in diathesis-stress models of schizophrenia. More recent studies, however, have called for extending the boundaries of the ARMS construct beyond attenuated psychosis in nonhelp-seeking samples to include not only other vulnerability indicators but also protective factors related to genotype, mental health, personality, and cognition. Method Accordingly, we assessed in a sample of 100 college students, the ARMS construct with the Brief Prodromal Questionnaire (PQ-B) for psychosis, in conjunction with measures of positive mental health, childhood adversity, psychiatric symptoms, personality traits, social cognition, and genetic variables derived from assays of the serotonin transporter (5-HTTLPR) and the brain-derived neurotrophic factor (BDNF). Results Higher PQ-B scores correlated positively with vulnerability indicators of childhood adversity and heightened levels of a wide variety of psychiatric symptoms but correlated negatively with protective factors of better overall mental health, social cognition as well as with a distinct NEO profile marked by reduced neuroticism and elevated agreeableness and conscientiousness. Multivariate analyses indicated that a composite ARMS measure comprised of PQ-B scores plus anxiety and depression symptoms revealed significant genotype differences, with lowest risk and highest resilience for allelic carriers of 5-HTTLPR-short and BDNF Met polymorphisms. Conclusions Results provided support for extending the ARMS construct, pointing to important contributions of personality, social cognition, and genes that support neural plasticity in mitigating vulnerability and enhancing resilience and well-being.
Lawal OU, Barata M, Fraqueza MJ, Worning P, Bartels MD, Goncalves L, Paixao P, Goncalves E, Toscano C, Empel J, Urbas M, Domiinguez MA, Westh H, de Lencastre H, Miragaia M
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Staphylococcus saprophyticus From Clinical and Environmental Origins Have Distinct Biofilm Composition

FRONTIERS IN MICROBIOLOGY 2021 JUN 7; 12(?):? Article 663768
Biofilm formation has been shown to be critical to the success of uropathogens. Although Staphylococcus saprophyticus is a common cause of urinary tract infections, its biofilm production capacity, composition, genetic basis, and origin are poorly understood. We investigated biofilm formation in a large and diverse collection of S. saprophyticus (n = 422). Biofilm matrix composition was assessed in representative strains (n = 63) belonging to two main S. saprophyticus lineages (G and S) recovered from human infection, colonization, and food-related environment using biofilm detachment approach. To identify factors that could be associated with biofilm formation and structure variation, we used a pangenome-wide association study approach. Almost all the isolates (91%; n = 384/422) produced biofilm. Among the 63 representative strains, we identified eight biofilm matrix phenotypes, but the most common were composed of protein or protein-extracellular DNA (eDNA)-polysaccharides (38%, 24/63 each). Biofilms containing protein-eDNA-polysaccharides were linked to lineage G and environmental isolates, whereas protein-based biofilms were produced by lineage S and infection isolates (p < 0.05). Putative biofilm-associated genes, namely, aas, atl, ebpS, uafA, sasF, sasD, sdrH, splE, sdrE, sdrC, sraP, and ica genes, were found with different frequencies (3-100%), but there was no correlation between their presence and biofilm production or matrix types. Notably, icaC_1 was ubiquitous in the collection, while icaR was lineage G-associated, and only four strains carried a complete ica gene cluster (icaADBCR) except one that was without icaR. We provided evidence, using a comparative genomic approach, that the complete icaADBCR cluster was acquired multiple times by S. saprophyticus and originated from other coagulase-negative staphylococci. Overall, the composition of S. saprophyticus biofilms was distinct in environmental and clinical isolates, suggesting that modulation of biofilm structure could be a key step in the pathogenicity of these bacteria. Moreover, biofilm production in S. saprophyticus is ica-independent, and the complete icaADBCR was acquired from other staphylococci.
Durkin SM, Chakraborty M, Abrieux A, Lewald KM, Gadau A, Svetec N, Peng JH, Kopyto M, Langer CB, Chiu JC, Emerson JJ, Zhao L
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Behavioral and Genomic Sensory Adaptations Underlying the Pest Activity of Drosophila suzukii

MOLECULAR BIOLOGY AND EVOLUTION 2021 JUN; 38(6):2532-2546
Studying how novel phenotypes originate and evolve is fundamental to the field of evolutionary biology as it allows us to understand how organismal diversity is generated and maintained. However, determining the basis of novel phenotypes is challenging as it involves orchestrated changes at multiple biological levels. Here, we aim to overcome this challenge by using a comparative species framework combining behavioral, gene expression, and genomic analyses to understand the evolutionary novel egg-laying substrate-choice behavior of the invasive pest species Drosophila suzukii. First, we used egg-laying behavioral assays to understand the evolution of ripe fruit oviposition preference in D. suzukii compared with closely related species D. subpulchrella and D. biarmipes as well as D. melanogaster. We show that D. subpulchrella and D. biarmipes lay eggs on both ripe and rotten fruits, suggesting that the transition to ripe fruit preference was gradual. Second, using two-choice oviposition assays, we studied how D. suzukii, D. subpulchrella, D. biarmipes, and D. melanogaster differentially process key sensory cues distinguishing ripe from rotten fruit during egg-laying. We found that D. suzukii's preference for ripe fruit is in part mediated through a species-specific preference for stiff substrates. Last, we sequenced and annotated a high-quality genome for D. subpulchrella. Using comparative genomic approaches, we identified candidate genes involved in D. suzukii's ability to seek out and target ripe fruits. Our results provide detail to the stepwise evolution of pest activity in D. suzukii, indicating important cues used by this species when finding a host, and the molecular mechanisms potentially underlying their adaptation to a new ecological niche.
Gilligan CJ, Cohen SP, Fischetti VA, Hirsch JA, Czaplewski LG
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Chronic low back pain, bacterial infection and treatment with antibiotics

SPINE JOURNAL 2021 JUN; 21(6):903-914
The contribution of bacterial infection to chronic low back pain and its treatment with antibiotics have generated considerable controversy in literature. If efficacious, antibiotics have the potential to transform the treatment of chronic low back pain in a significant subset of patients. Some microbiology studies of disc tissue from patients with CLBP have shown that bacteria are present, most likely due to infection, while others conclude they are absent or if found, it is due to surgical contamination. Clinical studies testing the efficacy of oral antibiotics to treat CLBP have either shown that the treatment is efficacious leading to significantly reduced pain and disability or that their effect is modest and not clinically significant. Critical review of the literature on CLBP, bacterial infection and treatment with antibiotics identified five well-designed and executed microbiology studies characterizing bacteria in disc samples that demonstrate that bacteria do infect herniated disc tissue, but that the bacterial burden is low and may be below the limits of detection in some studies. Two randomized, controlled clinical trials evaluating oral antibiotics in patients with CLBP indicate that for certain subsets of patients, the reduction in pain and disability achieved with antibiotic therapy may be significant. In patients for whom other therapies have failed, and who might otherwise progress to disc replacement or fusion surgery, antibiotic therapy may well be an attractive option to reduce the individual suffering associated with this debilitating condition. Additional clinical research is recommended to refine the selection of patients with CLBP caused or complicated by bacterial infection and most likely to respond to antibiotics, to optimize antibiotic therapy to maximize patient benefit, to minimize and manage side effects, and to address legitimate concerns about antibiotic stewardship. (C) 2021 The Author(s). Published by Elsevier Inc.
Choe H, Jarvis ED
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The role of sex chromosomes and sex hormones in vocal learning systems

HORMONES AND BEHAVIOR 2021 JUN; 132(?):? Article 104978
Vocal learning is the ability to imitate and modify sounds through auditory experience, a rare trait found in only a few lineages of mammals and birds. It is a critical component of human spoken language, allowing us to verbally transmit speech repertoires and knowledge across generations. In many vocal learning species, the vocal learning trait is sexually dimorphic, where it is either limited to males or present in both sexes to different degrees. In humans, recent findings have revealed subtle sexual dimorphism in vocal learning/spoken language brain regions and some associated disorders. For songbirds, where the neural mechanisms of vocal learning have been well studied, vocal learning appears to have been present in both sexes at the origin of the lineage and was then independently lost in females of some subsequent lineages. This loss is associated with an interplay between sex chromosomes and sex steroid hormones. Even in species with little dimorphism, like humans, sex chromosomes and hormones still have some influence on learned vocalizations. Here we present a brief synthesis of these studies, in the context of sex determination broadly, and identify areas of needed investigation to further understand how sex chromosomes and sex steroid hormones help establish sexually dimorphic neural structures for vocal learning.
Niec RE, Rudensky AY, Fuchs E
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Inflammatory adaptation in barrier tissues

CELL 2021 JUN 24; 184(13):3361-3375
Surface epithelia provide a critical barrier to the outside world. Upon a barrier breach, resident epithelial and immune cells coordinate efforts to control infections and heal tissue damage. Inflammation can etch lasting marks within tissues, altering features such as scope and quality of future responses. By remembering inflammatory experiences, tissues are better equipped to quickly and robustly respond to barrier breaches. Alarmingly, in disease states, memory may fuel the inflammatory fire. Here, we review the cellular communication networks in barrier tissues and the integration between tissue-resident and recruited immune cells and tissue stem cells underlying tissue adaptation to environmental stress.