Biology subjects

Randall, A.

Publications and source records attributed to Randall, A..

4 recordsLinked to original sources

bioRxiv2023

Age-Associated Weaker Immunity to Coronaviruses is Characteristic of Children that Develop Multisystem Inflammatory Syndrome following SARS-CoV-2 Infection

We analyzed the antibody and cytokine responses of twenty-three patients with multisystem inflammatory syndrome of children (MIS-C) that appeared with a three-to-six-week delay following a mild or asymptomatic SARS-CoV-2 infection. These responses were compared to healthy convalescent pediatric COVID-19 patients approximately twenty-eight days after the onset of symptoms. Both groups had strong IgG responses to SARS-CoV-2 spike (S) and nucleocapsid (N) proteins, but the MIS-C patients had weaker antibody responses to certain epitopes in the SARS-CoV-2 S and N proteins and to the S and N proteins of endemic human coronaviruses (HCoV) compared to pediatric convalescent COVID patients. HCoV antibody reactivity was correlated with age. In contrast, MIS-C patients had elevated serum levels of several proinflammatory cytokines compared to convalescent COVID patients, including interleukins IL-6, IL-8, IL-18 and chemokines CCL2, CCL8, CXCL5, CXCL9 and CXCL10 as well as tumor necrosis factor alpha and interferon gamma. Moreover, many cytokine responses of MIS-C patients were positively correlated with antibody responses to the SARS-CoV-2 S, N, membrane and ORF3a proteins while pediatric convalescent COVID patient cytokine responses were more often negatively correlated with antibody responses to the S, N and ORF3a proteins of SARS-CoV-2.

immunology↗

bioRxiv2019

Imbalance in the response of pre- and post-synaptic components to amyloidopathy

Alzheimers disease (AD)-associated synaptic dysfunction drives the progression of pathology from its earliest stages. A{beta} species, both soluble and in plaque deposits, have been causally related to the progressive, structural and functional impairments observed in AD. It is, however, still unclear how A{beta} plaques develop over time and how they progressively affect local synapse density and turnover. Here we observed, in a mouse model of AD, that A{beta} plaques grow faster in the earlier stages of the disease and if their initial area is > 500 {micro}m2; this may be due to deposition occurring in the diffuse part of the plaque. In addition, synaptic turnover is higher in the presence of amyloid pathology and this is paralleled by a reduction in pre-but not post-synaptic densities. Plaque proximity does not appear to have an impact on synaptic dynamics. These observations indicate an imbalance in the response of the pre- and post-synaptic terminals and that therapeutics, alongside targeting the underlying pathology, need to address changes in synapse dynamics.

neuroscience↗

bioRxiv2019

Transcriptional signatures of progressive neuropathology in transgenic tau and amyloid mouse models.

The onset and progression of Alzheimers disease (AD) is characterized by increasing intracellular aggregation of hyperphosphorylated tau protein and accumulation of {beta}-amyloid (A{beta}) in the neocortex. Despite recent success in identifying genetic risk factors for AD the transcriptional mechanisms involved in disease progression are not fully understood. We used transgenic mice harbouring human tau (rTg4510) and amyloid precursor protein (J20) mutations to investigate transcriptional changes associated with the development of both tau and amyloid pathology. Using highly-parallel RNA sequencing we profiled transcriptional variation in the entorhinal cortex at four time points identifying robust genotype-associated differences in entorhinal cortex gene expression in both models. We quantified neuropathological burden across multiple brain regions in the same individual mice, identifying widespread changes in gene expression paralleling the development of tau pathology in rTg4510 mice. Differentially expressed transcripts included genes associated with familial AD from genetic studies of human patients, and genes annotated to both common and rare variants identified in GWAS and exome-sequencing studies of late-onset sporadic AD. Systems-level analyses identified discrete co-expression networks associated with the progressive accumulation of tau, with these enriched for genes and pathways previously implicated in the neuro-immunological and neurodegenerative processes driving AD pathology. Finally, we report considerable overlap between tau-associated networks and AD-associated co-expression modules identified in the human cortex. Our data provide further support for an immune-response component in the accumulation of tau, and reveal novel molecular pathways associated with the progression of AD neuropathology.

genomics↗

bioRxiv2017

Engagement of spinal- vs prefrontal-projecting locus coeruleus neurons parses analgesia from aversion & anxiety in rats

The locus coeruleus (LC) projects throughout the brain and spinal cord and is the major source of central noradrenaline. It remains unclear whether the LC acts functionally as a single global effector or as discrete modules. Specifically, while spinal-projections from LC neurons can exert analgesic actions, it is not known whether they can act independently of ascending LC projections. Using viral vectors taken up at axon terminals, we expressed chemogenetic actuators selectively in LC neurons with spinal (LC:SC) or prefrontal cortex (LC:PFC) projections. Activation of the LC:SC module produced robust, lateralised analgesia while activation of LC:PFC produced aversion. In a neuropathic pain model, LC:SC activation reduced hind-limb sensitization and induced conditioned place preference. By contrast, activation of LC:PFC exacerbated spontaneous pain, produced aversion and increased anxiety-like behaviour. This independent, contrasting modulation of pain-related behaviours mediated by distinct noradrenergic modules provides evidence for a discrete functional organisation of the LC.

neuroscience↗