Publications by authors named "James Nunez"

Programmable epigenome editors modify gene expression in mammalian cells by altering the local chromatin environment at target loci without inducing DNA breaks. However, the large size of CRISPR-based epigenome editors poses a challenge to their broad use in biomedical research and as future therapies. Here, we present Robust ENveloped Delivery of Epigenome-editor Ribonucleoproteins (RENDER) for transiently delivering programmable epigenetic repressors (CRISPRi, DNMT3A-3L-dCas9, CRISPRoff) and activator (TET1-dCas9) as ribonucleoprotein complexes into human cells to modulate gene expression.

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Article Synopsis
  • - The emergence of CRISPR technologies has revolutionized gene manipulation through innovations like epigenetic editing, which controls gene expression without altering DNA sequences or creating breaks in the genome.
  • - The CRISPRoff technology enables the establishment of repressive DNA and histone modifications at gene promoters, effectively silencing targeted genes in a way that is heritable through cell division.
  • - The article outlines protocols for delivering CRISPRoff via plasmid DNA and mRNA into various human cell types, while also offering evaluation methods for gene silencing and best practices for using CRISPRoff for gene perturbation.
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Computational imaging reconstructions from multiple measurements that are captured sequentially often suffer from motion artifacts if the scene is dynamic. We propose a neural space-time model (NSTM) that jointly estimates the scene and its motion dynamics, without data priors or pre-training. Hence, we can both remove motion artifacts and resolve sample dynamics from the same set of raw measurements used for the conventional reconstruction.

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Aim: The primary objective of this study is to determine the impact of a standardised feeding protocol for infants with gastroschisis on early enteral feeds, suck feeds, management of gastric residuals and breastfeeding at discharge. Secondary objectives were evaluation of growth, length of stay in neonatal intensive care unit (NICU), the duration of total parental nutrition (TPN), blood-culture confirmed sepsis and serum bilirubin level (SBR).

Methods: This single-centre retrospective quality improvement project included infants admitted to a quaternary care NICU for management of gastroschisis from 2010 to 2021.

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Article Synopsis
  • Researchers used a technique called Perturb-seq to study how disabling certain host factors affects SARS-CoV-2 infection in human lung cells.
  • They discovered that only a small number of these host factors significantly altered the infection process and the body’s immune response.
  • Notably, they identified specific factors, like IκBα and translation factors EIF4E2 and EIF4H, as critical for early stages of the infection, advancing understanding of how the virus interacts with host cells.
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Background: Mortality in infants with CHD is decreasing and focus has shifted to improving long-term outcomes. Growth and neurodevelopmental outcomes are important long-term endpoints for both clinicians and parents.

Objective: To evaluate growth and determine the impact of growth on neurodevelopmental outcomes at one year of age in infants who had an operative or therapeutic catheter procedure for CHD in neonatal period.

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Survival of infants with congenital anomalies requiring surgical correction has increased dramatically, shifting the focus of clinical care and research toward optimising growth and neurodevelopment.To determine the impact of growth on neurodevelopmental outcomes of infants with congenital surgical anomalies. Studies that reported association of growth with developmental outcomes in infants with congenital anomalies who had surgery, were eligible for inclusion.

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Aim: Congenital heart disease (CHD) is one of the most common birth defects affecting around 1:100 infants. In this systematic review, we aimed to determine impact of growth on neurodevelopmental outcomes of infants with CHD.

Methods: Studies that reported association of growth with developmental outcomes in infants with CHD who had surgery, were included.

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Article Synopsis
  • SARS-CoV-2 enters human cells by the Spike protein attaching to the ACE2 receptor, prompting researchers to use a targeted CRISPRi screen to explore ways to block this interaction.
  • The study identifies the BRD2 protein as crucial for the transcription of ACE2 in lung and heart cells, with BRD2 inhibitors being effective at hindering ACE2 expression and preventing SARS-CoV-2 infection.
  • Furthermore, the inhibition of BRD2 not only stops virus replication in Syrian hamsters but also impacts the transcription of other genes involved in the immune response, marking BRD2 as a significant target for COVID-19 therapies.
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A general approach for heritably altering gene expression has the potential to enable many discovery and therapeutic efforts. Here, we present CRISPRoff-a programmable epigenetic memory writer consisting of a single dead Cas9 fusion protein that establishes DNA methylation and repressive histone modifications. Transient CRISPRoff expression initiates highly specific DNA methylation and gene repression that is maintained through cell division and differentiation of stem cells to neurons.

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SARS-CoV-2 infection of human cells is initiated by the binding of the viral Spike protein to its cell-surface receptor ACE2. We conducted a targeted CRISPRi screen to uncover druggable pathways controlling Spike protein binding to human cells. We found that the protein BRD2 is required for transcription in human lung epithelial cells and cardiomyocytes, and BRD2 inhibitors currently evaluated in clinical trials potently block endogenous expression and SARS-CoV-2 infection of human cells, including those of human nasal epithelia.

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Background: Developmentally supportive environments are known to improve medical outcomes for hospitalized neonates and are considered the overarching philosophy for practice in the neonatal setting. Developmental rounds are a strategy incorporated by multidisciplinary teams to support development within and beyond the neonatal unit. Typically, they consist of bedside consultations and individualized developmentally supportive recommendations for families and clinicians.

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Ribosome profiling has revealed pervasive but largely uncharacterized translation outside of canonical coding sequences (CDSs). In this work, we exploit a systematic CRISPR-based screening strategy to identify hundreds of noncanonical CDSs that are essential for cellular growth and whose disruption elicits specific, robust transcriptomic and phenotypic changes in human cells. Functional characterization of the encoded microproteins reveals distinct cellular localizations, specific protein binding partners, and hundreds of microproteins that are presented by the human leukocyte antigen system.

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Background: Transdermal lidocaine patches have few systemic toxicities and may be useful analgesics in cardiac surgery patients. However, few studies have evaluated their efficacy in the perioperative setting. Objective To compare the efficacy of topical lidocaine 5% patch plus standard care (opioid and nonopioid analgesics) with standard care alone for postthoracotomy or poststernotomy pain in adult patients in a cardiothoracic intensive care unit.

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Targeted and inducible regulation of mammalian gene expression is a broadly important capability. We engineered drug-inducible catalytically inactive Cpf1 nuclease fused to transcriptional activation domains to tune the expression of endogenous genes in human cells. Leveraging the multiplex capability of the Cpf1 platform, we demonstrate both synergistic and combinatorial gene expression in human cells.

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Functional genomics efforts face tradeoffs between number of perturbations examined and complexity of phenotypes measured. We bridge this gap with Perturb-seq, which combines droplet-based single-cell RNA-seq with a strategy for barcoding CRISPR-mediated perturbations, allowing many perturbations to be profiled in pooled format. We applied Perturb-seq to dissect the mammalian unfolded protein response (UPR) using single and combinatorial CRISPR perturbations.

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Bacteria and archaea employ adaptive immunity against foreign genetic elements using CRISPR-Cas systems. To generate immunological memory, the Cas1-Cas2 protein complex captures 30-40 base pair segments of foreign DNA and catalyzes their integration into the host genome as unique spacer sequences. Although spacers are inserted strictly at the A-T-rich leader end of CRISPR loci in vivo, the molecular mechanism of leader-specific spacer integration remains poorly understood.

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The application of the CRISPR-Cas9 system for genome engineering has revolutionized the ability to interrogate genomes of mammalian cells. Programming the Cas9 endonuclease to induce DNA breaks at specified sites is achieved by simply modifying the sequence of its cognate guide RNA. Although Cas9-mediated genome editing has been shown to be highly specific, cleavage events at off-target sites have also been reported.

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Bacteria and archaea possess a range of defense mechanisms to combat plasmids and viral infections. Unique among these are the CRISPR-Cas (clustered regularly interspaced short palindromic repeats-CRISPR associated) systems, which provide adaptive immunity against foreign nucleic acids. CRISPR systems function by acquiring genetic records of invaders to facilitate robust interference upon reinfection.

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Bacteria and archaea generate adaptive immunity against phages and plasmids by integrating foreign DNA of specific 30-40-base-pair lengths into clustered regularly interspaced short palindromic repeat (CRISPR) loci as spacer segments. The universally conserved Cas1-Cas2 integrase complex catalyses spacer acquisition using a direct nucleophilic integration mechanism similar to retroviral integrases and transposases. How the Cas1-Cas2 complex selects foreign DNA substrates for integration remains unknown.

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Bacteria and archaea insert spacer sequences acquired from foreign DNAs into CRISPR loci to generate immunological memory. The Escherichia coli Cas1-Cas2 complex mediates spacer acquisition in vivo, but the molecular mechanism of this process is unknown. Here we show that the purified Cas1-Cas2 complex integrates oligonucleotide DNA substrates into acceptor DNA to yield products similar to those generated by retroviral integrases and transposases.

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The initial stage of CRISPR-Cas immunity involves the integration of foreign DNA spacer segments into the host genomic CRISPR locus. The nucleases Cas1 and Cas2 are the only proteins conserved among all CRISPR-Cas systems, yet the molecular functions of these proteins during immunity are unknown. Here we show that Cas1 and Cas2 from Escherichia coli form a stable complex that is essential for spacer acquisition and determine the 2.

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The PHD finger protein 1 (PHF1) is essential in epigenetic regulation and genome maintenance. Here we show that the Tudor domain of human PHF1 binds to histone H3 trimethylated at Lys36 (H3K36me3). We report a 1.

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