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Biology subjects

Doran, E.

Publications and source records attributed to Doran, E..

8 recordsLinked to original sources

An auditory advantage of Rdl-resistant mosquitoes may promote its persistence in urban environments

Despite dieldrin being discontinued, resistance mutations in the GABA-gated chloride channel RDL (Resistance to dieldrin) continue at high frequencies in natural malaria mosquitoes, suggesting a selective advantage. We showed that RDL modulates the mosquito auditory sensitivity. Because acoustic recognition is essential for mate acquisition, we hypothesized that resistance mutations confer a pleiotropic effect on mating success, with potential consequences for sexual selection. We provide laboratory evidence that resistance mutations enhance auditory and mating behaviours. We then conduct field collections in the city of Bangui (Central African Republic) and rural areas, revealing an association between Rdl resistance genotypes and urban settings, and within the city, with the noisiest locations. We also show decreased mating success of susceptible females with increasing noise levels, suggesting detrimental effects. Together, our findings support that Rdl resistance mutations enhance auditory function and mating success. We propose that this auditory advantage may contribute, together with other selective pressures such as cross-selection by other insecticides, to the persistence of these alleles in nature and may facilitate urban colonization by malaria vectors.

evolutionary biology↗

Combined antagonism of Oncostatin M (OSM) and Interleukin 6 (IL-6) provides both anti-fibrotic and anti-inflammatory benefit in pulmonary fibrosis

Interstitial lung diseases (ILDs), including idiopathic pulmonary fibrosis (IPF) and systemic sclerosis-associated ILD (SSc-ILD), are irreversible fibrosing diseases with a mean survival time of less than 5 years for IPF. Poorly understood etiology and complex pathogenesis of these diseases have hampered the identification and development of effective therapeutics. Existing treatments can slow progressive fibrosis and lung function decline but do not stop it entirely, resulting in a minimal impact on patient survival. Thus, novel therapeutic interventions are needed. Tocilizumab, an anti-IL-6 receptor antibody, was recently approved by FDA for the treatment of SSc-ILD based on evidence demonstrating a reduction in the rate of lung function decline. In this study, we have characterized an IL-6-driven feed-forward myeloid axis contributing to lung inflammation providing a mechanistic hypothesis for tocilizumab. Concomitantly we have identified an oncostatin M (OSM) orchestrated lung injury response contributing to epithelial and endothelial cell disruption, myofibroblast activation and fibrosis. Despite dysregulated expression of IL11 in IPF, SSc-ILD, and murine models of fibrosis, we found no evidence for a pro-fibrotic role for IL-11 in vitro or in vivo. Instead, in pre-clinical models of IPF we demonstrate that antagonism of OSM alone, or to a greater degree in combination with IL-6, reduced lung fibrosis and inflammation. Translating these observations, we validated gp130:OSMR, rather than gp130:LIFR, as the dominant human receptor complex used by OSM, identifying OSMR as a potential therapeutic target to stall fibrosis.

immunology↗

IFNAR1. Neutrophils Orchestrate Chronic Inflammatory Damage Through Mitochondrial Remodeling

Neutrophils are abundant innate effector cells that drive mucosal inflammation, yet the mechanisms by which they contribute to chronic inflammatory diseases across distinct tissues remain incompletely understood. Here, by reanalyzing single-cell RNA-seq datasets from patients with inflammatory bowel disease (IBD) and chronic obstructive pulmonary disease (COPD), we identify a shared neutrophil activation program enriched for type I interferon (IFN) signaling, nuclear factor-{kappa}B (NF-{kappa}B) and AP-1 transcriptional regulators, and effector pathways including NETosis, degranulation, and leukocyte trafficking. To interrogate these signatures, we established a CRISPR-compatible neutrophil differentiation platform from adult CD34 progenitors, which yielded cells closely resembling primary neutrophils at transcriptomic, proteomic, and functional levels. A targeted CRISPR-Cas9 screen revealed a central role for the mitochondrial iron transporter mitoferrin-1 (SLC25A37) in coordinating neutrophil oxidative phosphorylation, NET formation, and type I IFN production downstream of TLR9. Mechanistically, we show that NET-derived citrullinated histones activate an autocrine IFN-IFNAR1 loop, amplifying neutrophil inflammatory functions without impairing phagocytosis. Disruption of this loop, through IFNAR1 depletion or blockade, dampened neutrophil-driven tissue damage in human intestinal and alveolar organoid co-cultures as well as in murine models of colitis and cigarette smoke-induced lung inflammation. These findings uncover a conserved IFN-driven metabolic circuit in neutrophils that underpins pathology across chronic mucosal diseases and identify IFNAR1 as a therapeutic node to selectively disarm neutrophil-mediated tissue injury.

immunology↗

Controlling malaria mosquito reproduction via the octopamine beta2 receptor

Mosquito reproduction in a broad sense involves multiple steps from acoustic recognition of mating partners to egg hatching. We show that the octopamine receptor AgOct{beta}2R controls different aspects of this process in a sexually dimorphic manner. AgOct{beta}2R knockout males present auditory defects that impair their ability to inseminate females, whilst knockout females are sterile. These phenotypes suggest AgOct{beta}2R as a target to impair mosquito reproduction at multiple levels. We test the reproductive effects of the insecticide amitraz, an AgOct{beta}2R agonist, showing that amitraz exposure reduces insemination in the lab but not in the field and has no effects on female sterility, excluding its applicability as a mating disruptor. Pharmacological assays reveal that AgOct{beta}2R sensitivity to amitraz is reduced compared to other arthropods, but its responses can be altered by modifying residues in the binding pocket. Together, our results establish AgOct{beta}2R as a promising target to disrupt mosquito reproduction but emphasize the necessity of developing new tools to exploit this approach.

neuroscience↗

Apolipoprotein E abundance is elevated in the brains of individuals with Down syndrome-Alzheimer's disease

Trisomy of chromosome 21, the cause of Down syndrome (DS), is the most commonly occurring genetic cause of Alzheimers disease (AD). Here, we compare the frontal cortex proteome of people with Down syndrome-Alzheimers disease (DSAD) to demographically matched cases of early-onset AD and healthy ageing controls. We find wide dysregulation of the proteome, beyond proteins encoded by chromosome 21, including an increase in the abundance of the key AD-associated protein, APOE, in people with DSAD compared to matched cases of AD. To understand the cell types that may contribute to changes in protein abundance, we undertook a matched single-nuclei RNA-sequencing study, which demonstrated that APOE expression was elevated in subtypes of astrocytes, endothelial cells and pericytes in DSAD. We further investigate how trisomy 21 may cause increased APOE. Increased abundance of APOE may impact the development of, or response to, AD pathology in the brain of people with DSAD, altering disease mechanisms with clinical implications. Overall, these data highlight that trisomy 21 alters both the transcriptome and proteome of people with DS in the context of AD, and that these differences should be considered when selecting therapeutic strategies for this vulnerable group of individuals who have high-risk of early-onset dementia.

neuroscience↗

Spatial and single-nucleus transcriptomic analysis of genetic and sporadic forms of Alzheimer's Disease

The pathogenesis of Alzheimers disease (AD) depends on environmental and heritable factors, with remarkable differences evident between individuals at the molecular level. Here we present a transcriptomic survey of AD using spatial transcriptomics (ST) and single-nucleus RNA-seq in cortical samples from early-stage AD, late-stage AD, and AD in Down Syndrome (AD in DS) donors. Studying AD in DS provides an opportunity to enhance our understanding of the AD transcriptome, potentially bridging the gap between genetic mouse models and sporadic AD. Our analysis revealed spatial and cell-type specific changes in disease, with broad similarities in these changes between sAD and AD in DS. We performed additional ST experiments in a disease timecourse of 5xFAD and wildtype mice to facilitate cross-species comparisons. Finally, amyloid plaque and fibril imaging in the same tissue samples used for ST enabled us to directly link changes in gene expression with accumulation and spread of pathology.

neuroscience↗

Brain Amyloid and the Transition to Dementia in Down Syndrome

INTRODUCTIONDown syndrome (DS) is associated with elevated risk for Alzheimers disease (AD) due to beta amyloid (A{beta}) lifelong accumulation. We hypothesized that the spatial distribution of brain A{beta} predicts future dementia conversion in individuals with DS. METHODSWe acquired 18F-Florbetapir PET scans from 19 nondemented individuals with DS at baseline and monitored them for four years, with five individuals transitioning to dementia. Machine learning classification determined features on 18F-Florbetapir standardized uptake value ratio (SUVR) maps that predicted transition. RESULTSIn addition to "AD signature" regions including the inferior parietal cortex, temporal lobes, and the cingulum, we found that A{beta} cortical binding in the prefrontal and superior frontal cortices distinguished subjects who transitioned to dementia. Classification did well in predicting transitioners. DISCUSSIONOur study suggests that specific regional profiles of brain amyloid in older adults with DS may predict cognitive decline and are informative in evaluating the risk for dementia. HighlightsO_LIRegional [18F]-Florbetapir PET predicts future transition to dementia in Downs Syndrome. C_LIO_LIIncreased amyloid in prefrontal, inferior parietal, superior frontal, rostral middle frontal, and posterior cingulate cortices detect transitioiners, with prefrontal and superior frontal being best overall. C_LIO_LIAmyloid PET-based classification able to discriminate between transitioners and non-transitioners. C_LI

neuroscience↗

-Florbetapir PET: Towards Predicting Dementia in Adults with Down Syndrome

1. Background 1. Background 2. Methods 3. Results 4. Discussion 5. Conclusions References Individuals with Down syndrome (DS) have an increasing age-related prevalence of Alzheimers disease (AD). In DS, the triplication of amyloid precursor protein (APP) on chromosome 21 contributes to a life-long accumulation of brain amyloid (A{beta}) [1]. Dyshomeostasis of A{beta} has emerged as one of the most well-validated factors in the pathogenesis of AD [2]. By age 40 years, virtually all individuals with DS have amyloid plaques and tau tangles, hallmark pathologies that are characteristic of sporadic AD in the general population [3]. Dementia, while not inevitable in DS, increases significantly in prevalence with age to over 75% after age 65 years. [ ...

neuroscience↗