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Found 37769 matches. Displaying 1491-1500
Sten TH, Li RF, Otopalik A, Ruta V
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Sexual arousal gates visual processing during Drosophila courtship

NATURE 2021 JUL 22; 595(7868):549-553
Long-lasting internal arousal states motivate and pattern ongoing behaviour, enabling the temporary emergence of innate behavioural programs that serve the needs of an animal, such as fighting, feeding, and mating. However, how internal states shape sensory processing or behaviour remains unclear. In Drosophila, male flies perform a lengthy and elaborate courtship ritual that is triggered by the activation of sexually dimorphic P1 neurons(1-5), during which they faithfully follow and sing to a female(6,7). Here, by recording from males as they court a virtual 'female', we gain insight into how the salience of visual cues is transformed by a male's internal arousal state to give rise to persistent courtship pursuit. The gain of LC10a visual projection neurons is selectively increased during courtship, enhancing their sensitivity to moving targets. A concise network model indicates that visual signalling through the LC10a circuit, once amplified by P1-mediated arousal, almost fully specifies a male's tracking of a female. Furthermore, P1 neuron activity correlates with ongoing fluctuations in the intensity of a male's pursuit to continuously tune the gain of the LC10a pathway. Together, these results reveal how a male's internal state can dynamically modulate the propagation of visual signals through a high-fidelity visuomotor circuit to guide his moment-to-moment performance of courtship.
Yang L, Chan AKN, Miyashita K, Delaney CD, Wang X, Li HZ, Pokharel SP, Li S, Li ML, Xu XB, Lu W, Liu Q, Mattson N, Chen KY, Wang JH, Yuan YC, Horne D, Rosen ST, Soto-Feliciano Y, Feng ZH, Hoshii T, Xiao G, Muschen M, Chen JJ, Armstrong SA, Chen CW
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High-resolution characterization of gene function using single-cell CRISPR tiling screen

NATURE COMMUNICATIONS 2021 JUL 1; 12(1):? Article 4063
Identification of novel functional domains and characterization of detailed regulatory mechanisms in cancer-driving genes is critical for advanced cancer therapy. To date, CRISPR gene editing has primarily been applied to defining the role of individual genes. Recently, high-density mutagenesis via CRISPR tiling of gene-coding exons has been demonstrated to identify functional regions in genes. Furthermore, breakthroughs in combining CRISPR library screens with single-cell droplet RNA sequencing (sc-RNAseq) platforms have revealed the capacity to monitor gene expression changes upon genetic perturbations at single-cell resolution. Here, we present "sc-Tiling," which integrates a CRISPR gene-tiling screen with single-cell transcriptomic and protein structural analyses. Distinct from other reported single-cell CRISPR screens focused on observing gene function and gene-to-gene/enhancer-to-gene regulation, sc-Tiling enables the capacity to identify regulatory mechanisms within a gene-coding region that dictate gene activity and therapeutic response. Identifying functional domains and genetic regulatory mechanisms is essential for developing new therapies. Here the authors present sc-Tiling, single-cell high-density CRISPR tiling screening for functional domain characterization.
Navrazhina K, Renert-Yuval Y, Frew JW, Grand D, Gonzalez J, Williams SC, Garcet S, Krueger JG
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Large-scale serum analysis identifies unique systemic biomarkers in psoriasis and hidradenitis suppurativa

BRITISH JOURNAL OF DERMATOLOGY
Background Hidradenitis suppurativa (HS) is now recognized as a systemic inflammatory disease, sharing molecular similarities with psoriasis. Direct comparison of the systemic inflammation in HS with psoriasis is lacking. Objectives To evaluate the serum proteome of HS and psoriasis, and to identify biomarkers associated with disease severity. Methods In this cross-sectional study, 1536 serum proteins were assessed using the Olink Explore (Proximity Extension Assay) high-throughput panel in patients with moderate-to-severe HS (n = 11), patients with psoriasis (n = 10) and age- and body mass index-matched healthy controls (n = 10). Results HS displayed an overall greater dysregulation of circulating proteins, with 434 differentially expressed proteins (absolute fold change >= 1 center dot 2; P <= 0 center dot 05) in patients with HS vs. controls, 138 in patients with psoriasis vs. controls and 503 between patients with HS and patients with psoriasis. Interleukin (IL)-17A levels and T helper (Th)1/Th17 pathway enrichment were comparable between diseases, while HS presented greater tumour necrosis factor- and IL-1 beta-related signalling. The Th17-associated markers peptidase inhibitor 3 (PI3) and lipocalin 2 (LCN2) were able to differentiate psoriasis from HS accurately. Both diseases presented increases of atherosclerosis-related proteins. Robust correlations between clinical severity scores and immune and atherosclerosis-related proteins were observed across both diseases. Conclusions HS and psoriasis share significant Th1/Th17 enrichment and upregulation of atherosclerosis-related proteins. Despite the greater body surface area involved in psoriasis, HS presents a greater serum inflammatory burden.
Stern SA, Azevedo EP, Pomeranz LE, Doerig KR, Ivan VJ, Friedman JM
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Top-down control of conditioned overconsumption is mediated by insular cortex Nos1 neurons

CELL METABOLISM 2021 JUL 6; 33(7):1418-1432.e6
Associative learning allows animals to adapt their behavior in response to environmental cues. For example, sensory cues associated with food availability can trigger overconsumption even in sated animals. However, the neural mechanisms mediating cue-driven non-homeostatic feeding are poorly understood. To study this, we recently developed a behavioral task in which contextual cues increase feeding even in sated mice. Here, we show that an insular cortex to central amygdala circuit is necessary for conditioned overconsumption, but not for homeostatic feeding. This projection is marked by a population of glutamatergic nitric oxide synthase1 (Nos1)-expressing neurons, which are specifically active during feeding bouts. Finally, we show that activation of insular cortex Nos1 neurons suppresses satiety signals in the central amygdala. The data, thus, indicate that the insular cortex provides top-down control of homeostatic circuits to promote overconsumption in response to learned cues.
Campbell E, Lilic M
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Meet the authors: Mirjana Lilic and Elizabeth Campbell

MOLECULAR CELL 2021 JUL 15; 81(14):2869-2870
We talk to Mirjana (Mira) Lilic and Elizabeth (Liz) Campbell about their paper, "Structural basis of transcriptional activation by the Mycobacterium tuberculosis intrinsic antibiotic-resistance transcription factor WhiB7,'' the collaborations that made it happen, and the people who mentored and motivated them along the way.
Domzalski A, Perez SD, Yoo B, Velasquez A, Vigo V, Pasolli HA, Oldham AL, Henderson DP, Kawamura A
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Uncovering potential interspecies signaling factors in plant-derived mixed microbial culture

BIOORGANIC & MEDICINAL CHEMISTRY 2021 JUL 15; 42(?):? Article 116254
Microbes use signaling factors for intraspecies and interspecies communications. While many intraspecies signaling factors have been found and characterized, discovery of factors for interspecies communication is lagging behind. To facilitate the discovery of such factors, we explored the potential of a mixed microbial culture (MMC) derived from wheatgrass, in which heterogeneity of this microbial community might elicit signaling factors for interspecies communication. The stability of Wheatgrass MMC in terms of community structure and metabolic output was first characterized by 16S ribosomal RNA amplicon sequencing and liquid chromatography/mass spectrometry (LC/MS), respectively. In addition, detailed MS analyses led to the identification of 12hydroxystearic acid (12-HSA) as one of the major metabolites produced by Wheatgrass MMC. Stereochemical analysis revealed that Wheatgrass MMC produces mostly the (R)-isomer, although a small amount of the (S)isomer was also observed. Furthermore, 12-HSA was found to modulate planktonic growth and biofilm formation of various marine bacterial strains. The current study suggests that naturally derived MMCs could serve as a simple and reproducible platform to discover potential signaling factors for interspecies communication. In addition, the study indicates that hydroxylated long-chain fatty acids, such as 12-HSA, may constitute a new class of interspecies signaling factors.
Mookherjee D, Das S, Mukherjee R, Bera M, Jana SC, Chakrabarti S, Chakrabarti O
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RETREG1/FAM134B mediated autophagosomal degradation of AMFR/GP78 and OPA1-a dual organellar turnover mechanism

AUTOPHAGY 2021 JUL 3; 17(7):1729-1752
Turnover of cellular organelles, including endoplasmic reticulum (ER) and mitochondria, is orchestrated by an efficient cellular surveillance system. We have identified a mechanism for dual regulation of ER and mitochondria under stress. It is known that AMFR, an ER E3 ligase and ER-associated degradation (ERAD) regulator, degrades outer mitochondrial membrane (OMM) proteins, MFNs (mitofusins), via the proteasome and triggers mitophagy. We show that destabilized mitochondria are almost devoid of the OMM and generate "mitoplasts". This brings the inner mitochondrial membrane (IMM) in the proximity of the ER. When AMFR levels are high and the mitochondria are stressed, the reticulophagy regulatory protein RETREG1 participates in the formation of the mitophagophore by interacting with OPA1. Interestingly, OPA1 and other IMM proteins exhibit similar RETREG1-dependent autophagosomal degradation as AMFR, unlike most of the OMM proteins. The "mitoplasts" generated are degraded by reticulo-mito-phagy - simultaneously affecting dual organelle turnover.
Van Rompay KKA, Olstad KJ, Sammak RL, Dutra J, Watanabe JK, Usachenko JL, Immareddy R, Verma A, Lakshmanappa YS, Schmidt BA, Roh JW, Elizaldi SR, Allen AM, Muecksch F, Lorenzi JCC, Lockwood S, Pollard RE, Yee JL, Nham PB, Ardeshir A, Deere JD, Patterson J, Dang Q, Hatziioannou T, Bieniasz PD, Iyer SS, Hartigan-O'Connor DJ, Nussenzweig MC, Reader JR
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Early treatment with a combination of two potent neutralizing antibodies improves clinical outcomes and reduces virus replication and lung inflammation in SARS-CoV-2 infected macaques

PLOS PATHOGENS 2021 JUL; 17(7):? Article e1009688
There is an urgent need for effective therapeutic interventions against SARS-CoV-2, including new variants that continue to arise. Neutralizing monoclonal antibodies have shown promise in clinical studies. We investigated the therapeutic efficacy of a combination of two potent monoclonal antibodies, C135-LS and C144-LS that carry half-life extension mutations, in the rhesus macaque model of COVID-19. Twelve young adult macaques (three groups of four animals) were inoculated intranasally and intra-tracheally with a high dose of SARS-CoV-2 and 24 hours later, treated intravenously with a high (40 mg/kg) or low (12 mg/kg) dose of the C135-LS and C144-LS antibody combination, or a control monoclonal antibody. Animals were monitored for 7 days. Compared to the control animals, animals treated with either dose of the anti-SARS-CoV-2 antibodies showed similarly improved clinical scores, lower levels of virus replication in upper and lower respiratory tract, and significantly reduced interstitial pneumonia, as measured by comprehensive lung histology. In conclusion, this study provides proof-of-concept in support of further clinical development of these monoclonal antibodies against COVID-19 during early infection. Author summary Monoclonal antibodies that neutralize SARS-CoV-2 have shown promise in treating recently infected individuals who are at high risk of progression to severe COVID-19 disease. Although several monoclonal antibodies are currently being used in the clinic, there is an ongoing need to develop additional antibodies. The ideal monoclonal antibodies, or combinations, should be potent and durable, and maintain activity against emerging viral variants. In this study, we tested a combination of two potent monoclonal antibodies, C135-LS and C-144-LS, engineered to have long half-lives, in the macaque model of SARS-CoV-2 infection. Animals treated early after infection fared better than placebo-treated controls, manifesting fewer clinical signs, less virus replication in the respiratory tract, and reduced lung inflammation. These promising data support clinical testing of these monoclonal antibodies in humans and further development of similar antibody-based prophylactic and therapeutic strategies.
Wang ZJ, Muecksch F, Schaefer-Babajew D, Finkin S, Viant C, Gaebler C, Hoffmann HH, Barnes CO, Cipolla M, Ramos V, Oliveira TY, Cho AL, Schmidt F, Da Silva J, Bednarski E, Aguado L, Yee J, Daga M, Turroja M, Millard KG, Jankovic M, Gazumyan A, Zhao Z, Rice CM, Bieniasz PD, Caskey M, Hatziioannou T, Nussenzweig MC
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Naturally enhanced neutralizing breadth against SARS-CoV-2 one year after infection

NATURE 2021 JUL 15; 595(7867):426-431
More than one year after its inception, the coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains difficult to control despite the availability of several working vaccines. Progress in controlling the pandemic is slowed by the emergence of variants that appear to be more transmissible and more resistant to antibodies(1,2). Here we report on a cohort of 63 individuals who have recovered from COVID-19 assessed at 1.3, 6.2 and 12 months after SARS-CoV-2 infection, 41% of whom also received mRNA vaccines(3,4). In the absence of vaccination, antibody reactivity to the receptor binding domain (RBD) of SARS-CoV-2, neutralizing activity and the number of RBD-specific memory B cells remain relatively stable between 6 and 12 months after infection. Vaccination increases all components of the humoral response and, as expected, results in serum neutralizing activities against variants of concern similar to or greater than the neutralizing activity against the original Wuhan Hu-1 strain achieved by vaccination of naive individuals(2,5-8). The mechanism underlying these broad-based responses involves ongoing antibody somatic mutation, memory B cell clonal turnover and development of monoclonal antibodies that are exceptionally resistant to SARS-CoV-2 RBD mutations, including those found in the variants of concern(4,9). In addition, B cell clones expressing broad and potent antibodies are selectively retained in the repertoire over time and expand markedly after vaccination. The data suggest that immunity in convalescent individuals will be very long lasting and that convalescent individuals who receive available mRNA vaccines will produce antibodies and memory B cells that should be protective against circulating SARS-CoV-2 variants.
Huber T, Goldman O, Epstein AE, Stella G, Sakmar TP
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Principles and practice for SARS-CoV-2 decontamination of N95 masks with UV-C

BIOPHYSICAL JOURNAL 2021 JUL 20; 120(14):2927-2942
A mainstay of personal protective equipment during the coronavirus disease 2019 pandemic is the N95 filtering facepiece respirator. N95 respirators are commonly used to protect healthcare workers from respiratory pathogens, including the novel coronavirus severe acute respiratory syndrome coronavirus 2, and are increasingly employed by other frontline workers and the general public. Under routine circumstances, these masks are disposable, single-use items, but extended use and reuse practices have been broadly enacted to alleviate critical supply shortages during the coronavirus disease 2019 pandemic. Although extended-time single use presents a low risk of pathogen transfer, repeated donning and doffing of potentially contaminated masks presents increased risk of pathogen transfer. Therefore, efficient and safe decontamination methods for N95 masks are needed to reduce the risk of reuse and mitigate local supply shortages. Here, we review the available literature concerning use of germicidal ultraviolet-C (UV-C) light to decontaminate N95 masks. We propose a practical method for repeated point-of-use decontamination using commercially available UV-C cross-linker boxes from molecular biology laboratories to expose each side of the mask to 800-1200 mJ/cm(2) of UV-C. We measure the dose that penetrated to the interior of the respirators and model the potential germicidal action on coronaviruses. Our experimental results, in combination with modeled data, suggest that such a UV-C treatment cycle should induce a >3-log-order reduction in viral bioburden on the surface of the respirators and a 2-log-order reduction throughout the interior. We find that a dose 50-fold greater does not impair filtration or fit of 3M 8210 N95 masks, indicating that decontamination can be performed repeatedly. As such, UV-C germicidal irradiation is a practical strategy for small-scale point-of-use decontamination of N95s.