Biology subjects

Lawson, B.

Publications and source records attributed to Lawson, B..

7 recordsLinked to original sources

bioRxiv2026

Repeated and widespread introduction of a mosquito-borne virus, but wildlife impact remains localised in urban area

Mosquito-borne viruses are emerging in new regions with increasing regularity. Shifting climatic envelopes, especially in temperate regions, and altered enzootic cycles are changing likelihoods of persistence, meaning new approaches are required to predict and monitor establishment. Usutu virus (USUV) is a mosquito-borne viral zoonosis, which was first recorded in the United Kingdom in wild birds and mosquitoes in 2020. By developing a multidisciplinary approach, incorporating enhanced passive and active surveillance of wild birds, we discovered previously unrecorded introductions and identified USUV persistence and geographic expansion. By combining molecular and serological testing with citizen science derived datasets, we show an associated marked decline in a common, widespread, and highly susceptible host species (Eurasian Blackbird, Turdus merula). However, the clearest continuous signal of host population decline remains localised to a large urban area, despite the much wider virus distribution. This may be a consequence of an urban heat island effect and associated increase in length of the mosquito active season. Our results indicate that the establishment and impact of future mosquito-borne pathogens in temperate zones, anticipated under climate change, may first be most apparent in urban areas. Consequently, enhanced surveillance efforts in urban areas could provide an efficient mechanism for detecting novel pathogen emergence. The epidemiology of emerging vector-borne diseases, especially in temperate areas, depends on the interplay between climate, land-use and available hosts; therefore, considering each in isolation will not be sufficient to reliably inform surveillance or response planning.

ecology↗

bioRxiv2025

MiR-23b Neutralization In Brain Endothelium Promotes Blood-Brain Barrier Repair Through Wnt/Beta-catenin Dependent And Independent Mechanisms

Blood-brain barrier (BBB) disruption drives stroke and other CNS disorders pathology, yet restoring its integrity remains challenging. Using an unbiased anti-miR lentiviral screen, miR-23b was identified as a critical negative regulator of BBB integrity in brain endothelial cells (BECs). Targeted inhibition of miR-23b using anti-miR-23b, validated by Wnt-reporter, Wnt-rescue, and eCLIP analysis, demonstrates that BEC miR-23b silencing in BECs, enhances junctional protein expression and strengthens barrier function while suppressing transcellular transport. Global multi-omics analysis reveals that miR-23b acts as a robust driver of angiogenesis-specific genes and proteins. Conversely, anti-miR-23b induces the expression of factors essential for BBB stabilization and repair. Notably, anti-miR-23b enhances these protective barrier properties through the multi-faceted regulation of Wnt/{beta}-catenin, TGF-{beta}, Notch, and VEGF signaling mechanisms. Using a 3D microfluidic platform, anti-miR-23b was shown to foster BBB repair by accelerating vessel maturation and enhancing resilience against ischemic injury. Proof-of-concept studies show that BEC specific AAVBR1-anti-miR-23b gene therapy reinforces BBB tight junctions, reduces BBB leakage, and improves outcome measures in a transient middle cerebral artery occlusion (t-MCAO) stroke model. Thus, miR-23b is a critical regulator of cerebrovascular integrity, positioning anti-miR-23b as a promising RNA-based therapy to enhance BBB stability and repair in stroke and other CNS disorders.

neuroscience↗

bioRxiv2025

Detection of West Nile Virus via Retrospective Mosquito Arbovirus Surveillance in the United Kingdom

In March 2025, as part of on-going enhanced surveillance for mosquito-borne Orthoflaviviruses, West Nile virus (WNV) RNA was detected in two pools of female Aedes vexans collected in July 2023 in Nottinghamshire, England. Viral RNA detection was achieved via reverse transcription-qPCR. Sequencing and subsequent phylogenetic analysis of a 402 bp fragment indicated that the detections clustered with WNV lineage 1a. The exact origin of this virus remains unclear, but this finding indicates a historic WNV presence in the United Kingdom (UK). Surveillance has not provided evidence of further viral transmission to date.

molecular biology↗

bioRxiv2024

Transovarial transmission in field caught mosquitoes identifies a mechanism for the establishment of Usutu virus in a temperate country

Usutu virus (USUV) is an emerging zoonotic flavivirus in Europe, and the first zoonotic mosquito-borne virus to be confirmed in animal hosts in the United Kingdom (UK). Phylogenetic analysis of USUV in the three years following its initial detection in 2020 indicated that the virus is overwintering in the UK. In 2023, USUV was identified outside Greater London for the first time. Therefore, USUV should now be considered endemic within southeast England. Surveillance of avian hosts and mosquito vectors has been insufficient to elucidate the mechanism by which USUV has persisted through temperate winters. It is likely that mosquitoes play a significant role in facilitating the establishment of USUV in temperate areas, as is the case for related mosquito-borne viruses. Here we undertake enhanced targeted vector surveillance at the index site to investigate the role of mosquitoes in facilitating USUV establishment in the UK. Between 2021 and 2024 inclusive, we detected USUV in host-seeking adult female Culex pipiens s.l. (n = 8/554 pools), a key vector of the virus in Europe. During 2023, enhanced surveillance detected transovarial transmission of USUV in wild Cx. pipiens s.l. (n = 1/202 pools), by screening adults following captive rearing of mosquito larvae collected from the field. This is, to our knowledge, the first description of vertical transmission of USUV in an arthropod vector. Consequently, transovarial transmission should be considered a viable mechanism for the persistence of USUV in temperate areas. Our results highlight the importance of undertaking detailed vector surveillance, across life stages, to inform the epidemiology of vector-borne viruses.

microbiology↗

bioRxiv2022

Population genetic analysis of Ophidiomyces ophidiicola, the causative agent of snake fungal disease, indicates recent introductions to the USA

Snake fungal disease (SFD; ophidiomycosis), caused by the pathogen Ophidiomyces ophidiicola (Oo), has been documented in wild snakes in North America and Eurasia, and is considered an emerging disease in the eastern USA. However, a lack of historical disease data has made it challenging to determine whether Oo is a recent arrival to the USA or whether SFD emergence is due to other factors. Here, we examined the genomes of 82 Oo strains to determine the pathogens history in the eastern USA. Oo strains from the USA formed a clade (Clade II) distinct from European strains (Clade I), and molecular dating indicated that these clades diverged too recently ([~]2,000 years ago) for transcontinental dispersal of Oo to have occurred via natural snake movements across Beringia. A lack of nonrecombinant intermediates between clonal lineages in Clade II indicates that Oo has actually been introduced multiple times to North America from an unsampled source population, and molecular dating indicates that several of these introductions occurred within the last few hundred years. Molecular dating also indicated that the most common Clade II clonal lineages have expanded recently in the USA, with time of most recent common ancestor mean estimates ranging from 1985-2007 CE. The presence of Clade II in captive snakes worldwide demonstrates a potential mechanism of introduction and highlights that additional incursions are likely unless action is taken to reduce the risk of pathogen translocation and spillover into wild snake populations.

microbiology↗

bioRxiv2021

Quantitative analysis of tumour spheroid structure

Tumour spheroids are common in vitro experimental models of avascular tumour growth. Compared with traditional two-dimensional culture, tumour spheroids more closely mimic the avascular tumour microenvironment where spatial differences in nutrient availability strongly influence growth. We show that spheroids initiated using significantly different numbers of cells grow to similar limiting sizes, suggesting that avascular tumours have a limiting structure; in agreement with untested predictions of classical mathematical models of tumour spheroids. We develop a novel mathematical and statistical framework to study the structure of tumour spheroids seeded from cells transduced with fluorescent cell cycle indicators, enabling us to discriminate between arrested and cycling cells and identify an arrested region. Our analysis shows that transient spheroid structure is independent of initial spheroid size, and the limiting structure can be independent of seeding density. Standard experimental protocols compare spheroid size as a function of time; however, our analysis suggests that comparing spheroid structure as a function of overall size produces results that are relatively insensitive to variability in spheroid size. Our experimental observations are made using two melanoma cell lines, but our modelling framework applies across a wide range of spheroid culture conditions and cell lines.

cancer biology↗

bioRxiv2021

Genomic taxonomic assignment of individual root-knot nematodes

Root-knot nematodes (RKN; genus Meloidogyne) are polyphagous plant pathogens of great economic importance to agriculturalists globally. These species are small, diverse, and can be challenging for accurate taxonomic identification. Many of the most important crop pests confound analysis with simple genetic marker loci as they are polyploids of likely hybrid origin. Here we take a low-coverage, long-read genome sequencing approach to characterisation of individual root-knot nematodes. We demonstrate library preparation for Oxford Nanopore Technologies Flongle sequencing of low input DNA from individual juveniles and immature females, multiplexing up to twelve samples per flow cell. Taxonomic identification with Kraken 2 (a k-mer-based taxonomic assignment tool) is shown to reliably identify individual nematodes to species level, even within the very closely related Meloidogyne incognita group. Our approach forms a robust, low-cost, and scalable method for accurate RKN species diagnostics.

genomics↗