Coates, J. A. | Search bioRxiv

bioRxiv2020

Preprinting a pandemic: the role of preprints in the COVID-19 pandemic

The world continues to face a life-threatening viral pandemic. The virus underlying the COVID-19 disease, SARS-CoV-2, has caused over 98 million confirmed cases and 2.2 million deaths since January 2020. Although the most recent respiratory viral pandemic swept the globe only a decade ago, the way science operates and responds to current events has experienced a paradigm shift in the interim. The scientific community has responded rapidly to the COVID-19 pandemic, releasing over 125,000 COVID-19 related scientific articles within 10 months of the first confirmed case, of which more than 30,000 were hosted by preprint servers. We focused our analysis on bioRxiv and medRxiv, two growing preprint servers for biomedical research, investigating the attributes of COVID-19 preprints, their access and usage rates, as well as characteristics of their propagation on online platforms. Our data provides evidence for increased scientific and public engagement with preprints related to COVID-19 (COVID-19 preprints are accessed more, cited more, and shared more on various online platforms than non-COVID-19 preprints), as well as changes in the use of preprints by journalists and policymakers. We also find evidence for changes in preprinting and publishing behaviour: COVID-19 preprints are shorter and reviewed faster. Our results highlight the unprecedented role of preprints and preprint servers in the dissemination of COVID-19 science, and the impact of the pandemic on the scientific communication landscape.

scientific communication and education↗

bioRxiv2020

Identification of functionally-distinct macrophage subpopulations regulated by efferocytosis in Drosophila

Macrophages are a highly heterogeneous population of cells, with this diversity stemming in part from the existence of tissue resident populations and an ability to adopt a variety of activation states in response to stimuli. Drosophila blood cells (hemocytes) are dominated by a lineage of cells considered to be the functional equivalents of mammalian macrophages (plasmatocytes). Until very recently plasmatocytes were thought to be a homogeneous population. Here, we identify enhancer elements that label subpopulations of plasmatocytes, which vary in abundance across the lifecourse of the fly. We demonstrate that these plasmatocyte subpopulations behave in a functionally-distinct manner when compared to the overall population, including more potent migratory responses to injury and decreased clearance of apoptotic cells within the developing embryo. Additionally, these subpopulations display differential localisation and dynamics in pupae and adults, hinting at the presence of tissue-resident macrophages in the fly. Our enhancer analysis also allows us to identify novel candidate genes involved in plasmatocyte behaviour in vivo. Misexpression of one such enhancer-linked gene (calnexin14D) in all plasmatocytes improves wound responses, causing the overall population to behave more like the subpopulation marked by the calnexin14D-associated enhancer. Finally, we show that, we are able to modulate the number of cells within some subpopulations via exposure to increased levels of apoptotic cell death, thereby decreasing the number of plasmatocytes within more wound-responsive subpopulations. Taken together our data demonstrates the existence of macrophage heterogeneity in Drosophila and identifies mechanisms involved in the specification and function of these plasmatocyte subpopulations. Furthermore, this work identifies key molecular tools with which Drosophila can be used as a highly genetically-tractable, in vivo system to study the biology of macrophage heterogeneity.

developmental biology↗