Publications by authors named "Russell Snell"

Basal ganglia is proposed to mediate symptoms underlying bipolar disorder (BD). To understand the cell type-specific gene expression and network changes of BD basal ganglia, we performed single-nucleus RNA sequencing of 30,752 nuclei from caudate, putamen, globus pallidus, and substantia nigra of control human postmortem brain and 24,672 nuclei from BD brain. Differential expression analysis revealed major difference lying in caudate, with BD medium spiny neurons (MSNs) expressing significantly higher PDE5A, a cGMP-specific phosphodiesterase.

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Article Synopsis
  • * Researchers developed a transgenic sheep model (OVT73) to study HD, which shows early signs of the disease without motor symptoms or cell loss at a young age, aiding in understanding disease onset.
  • * A study of the sheep's brain revealed increased expression of certain receptors and transporters, suggesting that excitotoxicity from glutamate may trigger early neurodegeneration, but protective mechanisms could help buffer against cell damage.
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The biological mechanisms that explain how adverse early life events influence adult disease risk are poorly understood. One proposed mechanism is via the induction of accelerated biological aging, for which telomere length is considered a biomarker. We aimed to determine if maternal depression pre- and post-partum was associated with telomere length in children at 4 years of age (n = 4299).

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COVID-19 has caused calamitous health, economic and societal consequences. Although several COVID-19 vaccines have received full authorization for use, global deployment has faced political, financial and logistical challenges. The efficacy of first-generation COVID-19 vaccines is waning and breakthrough infections are allowing ongoing transmission and evolution of SARS-CoV-2.

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Background: Bovine lactoferrin (Lf) is an iron absorbing whey protein with antibacterial, antiviral, and antifungal activity. Lactoferrin is economically valuable and has an extremely variable concentration in milk, partly driven by environmental influences such as milking frequency, involution, or mastitis. A significant genetic influence has also been previously observed to regulate lactoferrin content in milk.

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Motivation: In recent years, improvements in throughput of single-cell RNA-seq have resulted in a significant increase in the number of cells profiled. The generation of single-cell RNA-seq datasets comprising >1 million cells is becoming increasingly common, giving rise to demands for more efficient computational workflows.

Results: We present an update to our single-cell RNA-seq analysis web server application, ICARUS (available at https://launch.

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Somatic instability of the huntingtin (HTT) CAG repeat mutation modifies age-at-onset of Huntington's disease (HD). Understanding the mechanism and pathogenic consequences of instability may reveal therapeutic targets. Using small-pool PCR we analyzed CAG instability in the OVT73 sheep model which expresses a full-length human cDNA HTT transgene.

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Background: Haploinsufficiency of the Lysine Methyltransferase 2C (KMT2C) gene results in the autosomal dominant disorder, Kleefstra syndrome 2. It is an extremely rare neurodevelopmental condition, with 14 previous reports describing varied clinical manifestations including dysmorphic features, delayed psychomotor development and delayed growth.

Methods: Here, we describe a female with global developmental delay, attention deficit disorder, dyspraxia, short stature and subtle non-specific dysmorphic features.

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Article Synopsis
  • CRISPR Cas9 gene editing presents new ways to address severe genetic defects, particularly in disorders like Common Variable Immunodeficiency (CVID), which often lack a clear genetic cause.
  • Many CVID patients do not have a defined genetic mutation, while those who do may be categorized as having a CVID-like disorder based on their inheritance patterns.
  • The essay discusses the promising applications of gene editing for studying underlying mechanisms of these disorders, while also addressing potential risks like collateral damage to genetic material.
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Huntington's disease (HD) is a debilitating neurodegenerative genetic disorder caused by an expanded polyglutamine-coding (CAG) trinucleotide repeat in the huntingtin () gene. HD behaves as a highly penetrant dominant disorder likely acting through a toxic gain of function by the mutant huntingtin protein. Widespread cellular degeneration of the medium spiny neurons of the caudate nucleus and putamen are responsible for the onset of symptomology that encompasses motor, cognitive, and behavioural abnormalities.

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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for coronavirus disease of 2019 (COVID-19), has caused havoc around the world. While several COVID-19 vaccines and drugs have been authorized for use, these antiviral drugs remain beyond the reach of most low- and middle-income countries. Rapid viral evolution is reducing the efficacy of vaccines and monoclonal antibodies and contributing to the deaths of some fully vaccinated persons.

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In vitro investigation of bovine lactation processes is limited by a lack of physiologically representative cell models. This deficiency is most evident through the minimal or absent expression of lactation-specific genes in cultured bovine mammary tissues. Primary bovine mammary epithelial cells (pbMECs) extracted from lactating mammary tissue and grown in culture initially express milk protein transcripts at relatively representative levels.

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  • * A case study is presented of a male infant who showed early signs of severe health issues, including apnoea and dystonic crises, leading to his death at 16 weeks, without seizure activity or other multisystem disease.
  • * Genetic analysis identified two biallelic variants in the CARS2 gene, affecting mitochondrial tRNA for cysteine, confirming this case as the earliest known instance of CARS2 deficiency with specific symptoms of dystonia and apnoea, but no epilepsy.
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Complex biological traits and disease often involve patterns of gene expression that can be characterised and examined. Here we present ICARUS v2.0, an update to our single cell RNA-seq analysis web server with additional tools to investigate gene networks and understand core patterns of gene regulation in relation to biological traits.

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Background: Identified DNA variants associated with serum 25-hydroxyvitamin vitamin D (25[OH]D) concentration may provide mechanistic insights into the vitamin D metabolic pathway in individuals. Our aim was to further characterise participants and their serum 25(OH)D concentration at baseline using candidate single nucleotide polymorphism (SNP) genotyping.

Methods: 5110 participants, aged 50-84 years, were recruited from the community.

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Rapid, cost-effective identification of genetic variants in small candidate genomic regions remains a challenge, particularly for less well equipped or lower throughput laboratories. The application of Oxford Nanopore Technologies' MinION sequencer has the potential to fulfil this requirement. We demonstrate a proof of concept for a multiplexing assay that pools PCR amplicons for MinION sequencing to enable sequencing of multiple templates from multiple individuals, which could be applied to gene-targeted diagnostics.

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Here we present ICARUS, a web server to enable users without experience in R to undertake single cell RNA-seq analysis. The focal point of ICARUS is its intuitive tutorial-style user interface, designed to guide logical navigation through the multitude of pre-processing, analysis and visualization steps. ICARUS is easily accessible through a dedicated web server (https://launch.

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Background: Milk samples from 10,641 dairy cattle were screened by a mass spectrometry method for extreme concentrations of the A or B isoforms of the whey protein, β-lactoglobulin (BLG), to identify causative genetic variation driving changes in BLG concentration.

Results: A cohort of cows, from a single sire family, was identified that produced milk containing a low concentration of the BLG B protein isoform. A genome-wide association study (GWAS) of BLG B protein isoform concentration in milk from AB heterozygous cows, detected a group of highly significant single nucleotide polymorphisms (SNPs) within or close to the BLG gene.

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Background: Economically important milk production traits including milk volume, milk fat and protein yield vary considerably across dairy goats in New Zealand. A significant portion of the variation is attributable to genetic variation. Discovery of genetic markers linked to milk production traits can be utilised to drive selection of high-performance animals.

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Alzheimer's disease (AD) is one of the looming health crises of the near future. Increasing lifespans and better medical treatment for other conditions mean that the prevalence of this disease is expected to triple by 2050. The impact of AD includes both the large toll on individuals and their families as well as a large financial cost to society.

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Background: The pathological mechanism of cellular dysfunction and death in Huntington's disease (HD) is not well defined. Our transgenic HD sheep model (OVT73) was generated to investigate these mechanisms and for therapeutic testing. One particular cohort of animals has undergone focused investigation resulting in a large interrelated multi-omic dataset, with statistically significant changes observed comparing OVT73 and control 'omic' profiles and reported in literature.

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