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The paper is devoted to the vocabulary of technical texts and lexical-grammatical transformations occurring in the result of translation through analyzing the constituents of technical vocabulary and grammatical peculiarities common to Source Language (SL) and Target Language (TL). This study shows how to work with the vocabulary of technical texts and the possible grammatical structures in order to make the sentences more comprehensible.

RNA interference is a natural antiviral mechanism that could be harnessed to combat SARS-CoV-2 infection by targeting and destroying the viral genome. We screened lipophilic small-interfering RNA (siRNA) conjugates targeting highly conserved regions of the SARS-CoV-2 genome and identified leads targeting outside of the spike-encoding region capable of achieving ≥3-log viral reduction. Serial passaging studies demonstrated that a two-siRNA combination prevented development of resistance compared to a single-siRNA approach. A two-siRNA combination delivered intranasally protected Syrian hamsters from weight loss and lung pathology by viral infection upon prophylactic administration but not following onset of infection. Together, the data support potential utility of RNAi as a prophylactic approach to limit SARS-CoV-2 infection that may help combat emergent variants, complement existing interventions, or protect populations where vaccines are less effective. Most importantly, this strategy has implications for developing medicines that may be valuable in protecting against future coronavirus pandemics.

VIR-7831 and VIR-7832 are dual action monoclonal antibodies (mAbs) targeting the spike glycoprotein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). VIR-7831 and VIR-7832 were derived from a parent antibody (S309) isolated from memory B cells of a 2003 severe acute respiratory syndrome coronavirus (SARS-CoV) survivor. Both mAbs contain an “LS” mutation in the Fc region to prolong serum half-life and potentially enhance distribution to the respiratory mucosa. In addition, VIR-7832 encodes an Fc GAALIE mutation that has been shown previously to evoke CD8+ T-cells in the context of an in vivo viral respiratory infection. VIR-7831 and VIR-7832 potently neutralize wild-type and variant authentic virus in vitro as well as variant pseudotyped viruses. In addition, they retain activity against monoclonal antibody resistance mutations conferring reduced susceptibility to currently authorized mAbs. The VIR-7831/VIR-7832 epitope does not overlap with mutational sites in current variants of concern and continues to be highly conserved among circulating sequences consistent with the high barrier to resistance observed in vitro. Furthermore, both mAbs can recruit effector mechanisms in vitro that may contribute to clinical efficacy via elimination of infected host cells. In vitro studies with these mAbs demonstrated no enhancement of infection. In a Syrian Golden hamster proof-of concept wildtype SARS-CoV-2 infection model, animals treated with VIR-7831 had less weight loss, and significantly decreased total viral load and infectious virus levels in the lung compared to a control mAb. Taken together, these data indicate that VIR-7831 and VIR-7832 are promising new agents in the fight against COVID-19.

Human embryonic stem cells (hESCs) can be captured in a primed state in which they resemble the postimplantation epiblast, or in a naive state where they resemble the preimplantation epiblast. Naive-cell-specific culture conditions allow the study of preimplantation development ex vivo but reportedly lead to chromosomal abnormalities, which compromises their utility in research and potential therapeutic applications. Although MEK inhibition is essential for the naive state, here we show that reduced MEK inhibition facilitated the establishment and maintenance of naive hESCs that retained naive-cell-specific features, including global DNA hypomethylation, HERVK expression, and two active X chromosomes. We further show that hESCs cultured under these modified conditions proliferated more rapidly; accrued fewer chromosomal abnormalities; and displayed changes in the phosphorylation levels of MAPK components, regulators of DNA damage/repair, and cell cycle. We thus provide a simple modification to current methods that can enable robust growth and reduced genomic instability in naive hESCs.

Much attention has focussed on the conversion of human pluripotent stem cells (PSCs) to a more naïve developmental status. Here we provide a method for resetting via transient histone deacetylase inhibition. The protocol is effective across multiple PSC lines and can proceed without karyotype change. Reset cells can be expanded without feeders with a doubling time of around 24 h. WNT inhibition stabilises the resetting process. The transcriptome of reset cells diverges markedly from that of primed PSCs and shares features with human inner cell mass (ICM). Reset cells activate expression of primate-specific transposable elements. DNA methylation is globally reduced to a level equivalent to that in the ICM and is non-random, with gain of methylation at specific loci. Methylation imprints are mostly lost, however. Reset cells can be re-primed to undergo tri-lineage differentiation and germline specification. In female reset cells, appearance of biallelic X-linked gene transcription indicates reactivation of the silenced X chromosome. On reconversion to primed status, XIST-induced silencing restores monoallelic gene expression. The facile and robust conversion routine with accompanying data resources will enable widespread utilisation, interrogation, and refinement of candidate naïve cells., Highlighted article: A simple, transgene-free method is described for resetting human ESCs or iPSCs to a stable naïve status via transient histone deacetylase inhibition.

Applications of embryonic stem cells (ESCs) require faithful chromatin changes during differentiation, but the fate of the X chromosome state in differentiating ESCs is unclear. Female human ESC lines either carry two active X chromosomes (XaXa), an Xa and inactive X chromosome with or without XIST RNA coating (XiXIST+Xa;XiXa), or an Xa and an eroded Xi (XeXa) where the Xi no longer expresses XIST RNA and has partially reactivated. Here, we established XiXa, XeXa, and XaXa ESC lines and followed their X chromosome state during differentiation. Surprisingly, we found that the X state pre-existing in primed ESCs is maintained in differentiated cells. Consequently, differentiated XeXa and XaXa cells lacked XIST, did not induce X inactivation, and displayed higher X-linked gene expression than XiXa cells. These results demonstrate that X chromosome dosage compensation is not required for ESC differentiation. Our data imply that XiXIST+Xa ESCs are most suited for downstream applications and show that all other X states are abnormal byproducts of our ESC derivation and propagation method.

The rate of glycolytic metabolism changes during differentiation of human embryonic stem cells (hESCs) and reprogramming of somatic cells to pluripotency. However, the functional contribution of glycolytic metabolism to the pluripotent state is unclear. Here we show that naive hESCs exhibit increased glycolytic flux, MYC transcriptional activity, and nuclear N-MYC localization relative to primed hESCs. This status is consistent with the inner cell mass of human blastocysts, where MYC transcriptional activity is higher than in primed hESCs and nuclear N-MYC levels are elevated. Reduction of glycolysis decreases self-renewal of naive hESCs and feeder-free primed hESCs, but not primed hESCs grown in feeder-supported conditions. Reduction of glycolysis in feeder-free primed hESCs also enhances neural specification. These findings reveal associations between glycolytic metabolism and human naive pluripotency and differences in the metabolism of feeder-/feeder-free cultured hESCs. They may also suggest methods for regulating self-renewal and initial cell fate specification of hESCs.

Human embryonic stem cells (hESCs) typically exhibit "primed" pluripotency, analogous to stem cells derived from the mouse post-implantation epiblast. This has led to a search for growth conditions that support self-renewal of hESCs akin to hypomethylated naive epiblast cells in human pre-implantation embryos. We have discovered that reverting primed hESCs to a hypomethylated naive state or deriving a new hESC line under naive conditions results in the establishment of Stage Specific Embryonic Antigen 4 (SSEA4)-negative hESC lines with a transcriptional program resembling the human pre-implantation epiblast. In contrast, we discovered that the methylome of naive hESCs in vitro is distinct from that of the human epiblast in vivo with loss of DNA methylation at primary imprints and a lost "memory" of the methylation state of the human oocyte. This failure to recover the naive epiblast methylation landscape appears to be a consistent feature of self-renewing hypomethylated naive hESCs in vitro.

In each somatic cell of a female mammal one X chromosome is transcriptionally silenced via X-chromosome inactivation (XCI), initiating early in development. Although XCI events are conserved in mouse and human postimplantation development, regulation of X-chromosome dosage in preimplantation development occurs differently. In preimplantation development, mouse embryos undergo imprinted form of XCI, yet humans lack imprinted XCI and instead regulate gene expression of both X chromosomes by dampening transcription. The long non-coding RNA Xist/XIST is expressed in mouse and human preimplantation and postimplantation development to orchestrate XCI, but its role in dampening is unclear. In this review, we discuss recent advances in our understanding of the role of Xist in X chromosome dosage compensation in mouse and human.

Much attention has focussed on the conversion of human pluripotent stem cells (PSCs) to a more naïve developmental status. Here we provide a method for resetting via transient histone deacetylase inhibition. The protocol is effective across multiple PSC lines and can proceed without karyotype change. Reset cells can be expanded without feeders with a doubling time of around 24 h. WNT inhibition stabilises the resetting process. The transcriptome of reset cells diverges markedly from that of primed PSCs and shares features with human inner cell mass (ICM). Reset cells activate expression of primate-specific transposable elements. DNA methylation is globally reduced to a level equivalent to that in the ICM and is non-random, with gain of methylation at specific loci. Methylation imprints are mostly lost, however. Reset cells can be re-primed to undergo tri-lineage differentiation and germline specification. In female reset cells, appearance of biallelic X-linked gene transcription indicates reactivation of the silenced X chromosome. On reconversion to primed status

Naive human embryonic stem cells (hESCs) can be derived from primed hESCs or directly from blastocysts, but their X chromosome state has remained unresolved. Here, we show that the inactive X chromosome (Xi) of primed hESCs was reactivated in naive culture conditions. Like cells of the blastocyst, the resulting naive cells contained two active X chromosomes with XIST expression and chromosome-wide transcriptional dampening and initiated XIST-mediated X inactivation upon differentiation. Both establishment of and exit from the naive state (differentiation) happened via an XIST-negative XaXa intermediate. Together, these findings identify a cell culture system for functionally exploring the two X chromosome dosage compensation processes in early human development: X dampening and X inactivation. However, remaining differences between naive hESCs and embryonic cells related to mono-allelic XIST expression and non-random X inactivation highlight the need for further culture improvement. As the naive state resets Xi abnormalities seen in primed hESCs, it may provide cells better suited for downstream applications.

Our understanding of human pre-implantation development is limited by the availability of human embryos and cannot completely rely on mouse studies. Petropoulos etal. now provide an extensive transcriptome analysis of a large number of human pre-implantation embryos at single-cell resolution, revealing previously unrecognized features unique to early human development.

We described earlier a dual-combination anti-HIV type 1 (HIV-1) lentiviral vector (LVsh5/C46) that downregulates CCR5 expression of transduced cells via RNAi and inhibits HIV-1 fusion via cell surface expression of cell membrane-anchored C46 antiviral peptide. This combinatorial approach has two points of inhibition for R5-tropic HIV-1 and is also active against X4-tropic HIV-1. Here, we utilize the humanized bone marrow, liver, thymus (BLT) mouse model to characterize the in vivo efficacy of LVsh5/C46 (Cal-1) vector to engineer cellular resistance to HIV-1 pathogenesis. Human CD34+ hematopoietic stem/progenitor cells (HSPC) either nonmodified or transduced with LVsh5/C46 vector were transplanted to generate control and treatment groups, respectively. Control and experimental groups displayed similar engraftment and multilineage hematopoietic differentiation that included robust CD4+ T-cell development. Splenocytes isolated from the treatment group were resistant to both R5- and X4-tropic HIV-1 during ex vivo challenge experiments. Treatment group animals challenged with R5-tropic HIV-1 displayed significant protection of CD4+ T-cells and reduced viral load within peripheral blood and lymphoid tissues up to 14 weeks postinfection. Gene-marking and transgene expression were confirmed stable at 26 weeks post-transplantation. These data strongly support the use of LVsh5/C46 lentiviral vector in gene and cell therapeutic applications for inhibition of HIV-1 infection.

The human blastocyst forms 5 days after one of the smallest human cells (the sperm) fertilizes one of the largest human cells (the egg). Depending on the sex-chromosome contribution from the sperm, the resulting embryo will either be female, with two X chromosomes (XX), or male, with an X and a Y chromosome (XY). In early development, one of the major differences between XX female and XY male embryos is the conserved process of X-chromosome inactivation (XCI), which compensates gene expression of the two female X chromosomes to match the dosage of the single X chromosome of males. Most of our understanding of the pre-XCI state and XCI establishment is based on mouse studies, but recent evidence from human pre-implantation embryo research suggests that many of the molecular steps defined in the mouse are not conserved in human. Here, we will discuss recent advances in understanding the control of X-chromosome dosage compensation in early human embryonic development and compare it to that of the mouse. This article is part of the themed issue ‘X-chromosome inactivation: a tribute to Mary Lyon’.