Biology subjects

Power, C.

Publications and source records attributed to Power, C..

11 recordsLinked to original sources

bioRxiv2026

Impact of HIV-1 infection on the microglia transcriptome: induction of microRNA-23b leads to G3BP2-mediated stress granules assembly disruption

Microglia act as HIV reservoirs in the brain and contribute to the development of HIV-associated neurocognitive disorders despite antiretroviral therapy. We examined the transcriptome of primary microglia infected ex vivo with HIV-1. Analyses reveal a significant modulation of DNA damage/cell cycle-, cellular stress- and non-membrane bounded organelle assembly-related gene expression, and a broad effect on the microRNA profile. MicroRNA-23b is identified among upregulated microRNAs in HIV-1-infected microglia, and downregulated g3bp2 mRNA, validated as its target. G3BP2 is a core component of stress granules (SGs), which serve as antiviral and proinflammatory platforms. MicroRNA-23b mimics reduced both G3BP2 expression and SG assembly in stress-induced monocyte-derived microglial cells (MDMi), and few SGs aggregate in infected MDMi. Inhibition of MicroRNA-23b partially re-established SG formation and reduced HIV-1 replication. Thus, microRNA-23b induction contributes to HIV-1 strategies aimed at counteracting SG assembly in infected microglia, a host response that restricts HIV-1 replication and ensuing neuropathogenesis.

microbiology↗

bioRxiv2026

Progressive Post-Acute Gut Microbiome Disruption Following SARS-CoV-2 Infection in Mice

SARS-CoV-2 infection is increasingly recognized to produce long-lasting physiological disturbances that extend beyond the acute phase. The gut microbiome has emerged as a potential contributor to post-infection outcomes, yet the longitudinal progression of microbial disruption following infection remains poorly defined. Here, we used a mouse model of SARS-CoV-2 infection to characterize gut microbiome dynamics at 7 (late acute phase), 14 (early recovery), and 21 (post-COVID condition, PCC) days post-infection (dpi). Viral RNA was detected in the lungs through 21 dpi. Longitudinal microbiome profiling revealed a two-phase restructuring marked by early shifts in Bacillota and Bacteroidota abundance, followed by pronounced post-acute dysbiosis characterized by reduced diversity, expansion of Bacillota, and near-complete loss of Bacteroidota. Functional pathway predictions showed progressive metabolic remodeling, including disruptions in nucleotide turnover, fermentation, and vitamin-related pathways. Together, these findings demonstrate that SARS-CoV-2 infection drives progressive and sustained alterations in gut microbial composition and function after the transition from acute infection through recovery into PCC.

microbiology↗

bioRxiv2025

Early pandemic HIV-1 integration site preferences differ across anatomical reservoirs

Despite effective viral suppression with modern antiretroviral therapy (ART), HIV-1 persists in latent reservoirs across multiple tissues. Integration into the host genome is essential for viral persistence, yet the characteristics of these reservoir sites across anatomical locations remain poorly understood. To address this, we analyzed integration sites from matched esophagus, PBL/PBMC, stomach, duodenum, colon, and unmatched brain tissue samples of individuals infected with HIV-1 subtype B. The virus used in this study was from 1993, an early stage of the HIV pandemic, providing insights into integration patterns before extensive ART use. Our analysis examined genomic feature enrichment, proximity to non-B DNA structures, integration hotspots, and site overlap across tissues and individuals. We identified a distinct integration pattern in brain tissue, characterized by reduced gene targeting and increased enrichment in Short Interspersed Nuclear Elements (SINEs) and DNase I hypersensitivity sites (DHS). Tissue-specific preferences for integration near non-B DNA structures were evident, alongside shared and unique hotspots across tissues and individuals. Notably, genes associated with HIV-related diseases were frequent integration targets. These findings underscore the complex interplay between viral integration, host genetics, and tissue-specific factors, highlighting the potential role of integration sites in disease development.

microbiology↗

bioRxiv2023

Genetic impacts on DNA methylation help elucidate regulatory genomic processes

Pinpointing genetic impacts on DNA methylation can improve our understanding of pathways that underlie gene regulation and disease risk. We report heritability and methylation quantitative trait locus (meQTL) analysis at 724,499 CpGs profiled with the Illumina Infinium MethylationEPIC array in 2,358 blood samples from three UK cohorts, with replication. Methylation levels at 34.2% of CpGs were affected by SNPs, and 98% of effects were cis-acting or within 1 Mbp of the tested CpG. Our results are consistent with meQTL analyses based on the former Illumina Infinium HumanMethylation450 array. Both meQTL SNPs and CpGs with meQTLs were overrepresented in enhancers, which have improved coverage on this platform compared to previous approaches. Co-localisation analyses across genetic effects on DNA methylation and 56 human traits identified 1,520 co-localisations across 1,325 unique CpGs and 34 phenotypes, including in disease-relevant genes, such ICOSLG (inflammatory bowel disease), and USP1 and DOCK7 (total cholesterol levels). Enrichment analysis of meQTLs and integration with expression QTLs gave insights into mechanisms underlying cis-meQTLs, for example through disruption of transcription factor binding sites for CTCF and SMC3, and trans-meQTLs, for example through regulating the expression of ACD and SENP7 which can modulate DNA methylation at distal sites. Our findings improve the characterisation of the mechanisms underlying DNA methylation variability and are informative for prioritisation of GWAS variants for functional follow-ups. A results database and viewer are available online.

genomics↗

bioRxiv2021

Mesoderm-Derived PDGFRA+ Cells Regulate the Emergence of Hematopoietic Stem Cells in the Dorsal Aorta

Mouse hematopoietic stem cells (HSCs) first emerge at embryonic day 10.5 (E10.5) on the ventral surface of the dorsal aorta, by endothelial-to-hematopoietic transition (EHT). We investigated whether cells with mesenchymal stem cell-like activity, which provide an essential niche for long-term HSCs (LT-HSCs) in the bone marrow, reside in the aorta- gonad-mesonephros (AGM) and contribute to the structural development of the dorsal aorta and EHT. Using transgenic mice, we demonstrate a lineage hierarchy for AGM stromal cells and traced the E10.5/E11.5 aortic endothelium and HSCs to mesoderm derived (Mesp1) PDGFRA+ stromal cells (Mesp1der PSCs). Mesp1der PSCs dominate the sub-endothelial and ventral stroma in the E10.5-E11.5 AGM but by E13.5 were replaced by neural crest (Wnt1) derived PDGFRA+ stromal cells (Wnt1der PSCs). Co-aggregating non-hemogenic embryonic and adult endothelial cells with Mesp1der PSCs but not with Wnt1der PSCs resulted in activation of a hematopoietic transcriptional program in endothelial cells accompanied by EHT and generation of LT-HSCs. Dose-dependent inhibition of PDGFRA signalling or BMP, WNT, NOTCH signalling interrupted this reprogramming event. This partnership between endothelial cells and AGM Mesp1der PSCs could potentially be harnessed to manufacture LT-HSCs from endothelium.

developmental biology↗

bioRxiv2021

Ultrasound-mediated blood-brain barrier disruption improves anti-pyroglutamate3 Aβ antibody efficacy and enhances phagocyte infiltration into brain in aged Alzheimer's disease-like mice

Pyroglutamate-3 amyloid-{beta} (pGlu3 A{beta}) is an N-terminally modified, toxic form of amyloid-{beta} that is present in cerebral amyloid plaques and vascular deposits. Using the Fc-competent murine anti-pGlu3 A{beta} monoclonal antibody (mAb), 07/2a, we present here a nonpharmacological approach using focused ultrasound (FUS) with intravenous (i.v.) injection of microbubbles (MB) to facilitate i.v. delivery of the 07/2a mAb across the blood brain barrier (BBB) in order to improve A{beta} removal and restore memory in aged APP/PS1 mice, an Alzheimers disease (AD)-like model of amyloidogenesis. Compared to sham-treated controls, aged APP/PS1 mice treated with 07/2a immediately prior to FUS-mediated BBB disruption (mAb + FUS-BBBD combination treatment) showed significantly better spatial learning and memory in the Water T Maze. FUS-BBBD treatment alone improved contextual fear learning and memory in aged WT and APP/PS1 mice, respectively. APP/PS1 mice given the combination treatment had reduced A{beta}42 and pGlu3 A{beta} hippocampal plaque burden compared to PBS-treated APP/PS1 mice. Hippocampal synaptic puncta density and synaptosomal synaptic protein levels were also higher in APP/PS1 mice treated with 07/2a just prior to BBB disruption. Increased Iba-1+ microglia were observed in the hippocampi of AD mice treated with 07/2a with and without FUS-BBBD, and APP/PS1 mice that received hippocampal BBB disruption and 07/2a showed increased Ly6G+ monocytes in hippocampal CA3. FUS-induced BBB disruption did not increase the incidence of microhemorrhage in mice with or without 07/2a mAb treatment. Our findings suggest that FUS is useful tool that may enhance delivery of an anti-pGlu3 A{beta} mAb for immunotherapy. FUS-mediated BBB disruption in combination with the 07/2a mAb also appears to facilitate monocyte infiltration in this AD model. Overall, these effects resulted in greater sparing of synapses and improved cognitive function without causing overt damage, suggesting the possibility of FUS as a noninvasive method to increase the therapeutic efficacy in AD patients.

bioengineering↗

bioRxiv2020

Nodosome inhibition as a novel broad-spectrum antiviral strategy against arboviruses and SARS-CoV-2

In the present report, we describe two small molecules with broad-spectrum antiviral activity. These drugs block formation of the nodosome. The studies were prompted by the observation that infection of human fetal brain cells with Zika virus (ZIKV) induces expression of nucleotide-binding oligomerization domain-containing protein 2 (NOD2), a host factor that was found to promote ZIKV replication and spread. A drug that targets NOD2 was shown to have potent broad-spectrum antiviral activity against other flaviviruses, alphaviruses and SARS-CoV-2, the causative agent of COVID-19. Another drug that inhibits the receptor-interacting serine/threonine-protein kinase 2 (RIPK2) which functions downstream of NOD2, also decreased replication of these pathogenic RNA viruses. The broad-spectrum action of nodosome targeting drugs is mediated, at least in part, by enhancement of the interferon response. Together, these results suggest that further preclinical investigation of nodosome inhibitors as potential broad-spectrum antivirals is warranted.

microbiology↗

bioRxiv2020

Induction of Muscle Regenerative Multipotent Stem Cells from Human Adipocytes by PDGF-AB and 5-Azacytidine.

Terminally differentiated murine osteocytes and adipocytes can be reprogrammed using platelet-derived growth factor-AB and 5-Azacytidine into multipotent stem cells with stromal cell characteristics. To generate a product that is amenable for therapeutic application, we have modified and optimised culture conditions to reprogram human adipocytes into induced multipotent stem cells (iMS) and expand them in vitro. The basal transcriptomes of adipocyte-derived iMS cells and matched adipose-tissue-derived mesenchymal stem cells were remarkably similar. However, there were distinct changes in histone modifications and CpG methylation at cis-regulatory regions consistent with an epigenetic landscape that was primed for tissue development and differentiation. In a non-specific tissue injury xenograft model, iMS cells contributed directly to new muscle, bone, cartilage and blood vessels with no evidence of teratogenic potential. In a cardiotoxin muscle injury model, iMS cells contributed specifically to satellite cells and myofibres without ectopic tissue formation. Taken together, human adipocyte derived iMS cells regenerate tissues in a context dependent manner without ectopic or neoplastic growth.

cell biology↗

bioRxiv2020

The Southern Bluefin Tuna mucosal microbiome is influenced by husbandry method, net pen location, and anti-parasite treatment

Aquaculture is the fastest growing primary industry worldwide. Marine finfish culture in open ocean net pens, or pontoons, is one of the largest growth areas and is currently the only way to rear high value fish such as bluefin tuna. Ranching involves catching wild juveniles, stocking in floating net pens and fattening for four to eight months. Tuna experience several parasite-induced disease challenges in culture that can be mitigated by application of praziquantel (PZQ) as a therapeutic. In this study, we characterized the microbiome of ranched southern Bluefin Tuna, Thunnus maccoyii, across four anatomic sites (gill, skin, digesta, and anterior kidney) and evaluated environmental and pathological factors that influence microbiome composition, including the impact of PZQ treatment on microbiome stability. Southern bluefin tuna gill, skin, and digesta microbiome communities are unique and potentially influenced by husbandry practices, location of pontoon growout pens, and treatment with the antiparasitic PZQ. There was no significant relationship between the fish mucosal microbiome and incidence or abundance of adult blood fluke in the heart or fluke egg density in the gill. An enhanced understanding of microbiome diversity and function in high-value farmed fish species such as bluefin tuna is needed to optimize fish health and improve aquaculture yield. Comparison of the bluefin tuna microbiome to other fish species, including Seriola lalandi (yellowtail kingfish), a common farmed species from Australia, and Scomber japonicus (Pacific mackerel), a wild caught Scombrid relative of tuna, showed the two Scombrids had more similar microbial communities compared to other families. The finding that mucosal microbial communities are more similar in phylogenetically related fish species exposes an opportunity to develop mackerel as a model for tuna microbiome and parasite research.

genomics↗

bioRxiv2020

Anti-inflammatory role of GM1 and modulatory effects of gangliosides on microglia functions

Gangliosides are sialic acid-containing glycosphingolipids highly enriched in the brain. Located mainly at the plasma membrane, gangliosides play important roles in signaling and cell-to-cell communication. Lack of gangliosides causes severe early onset neurodegenerative disorders, while more subtle deficits have been reported in Parkinsons disease and in Huntingtons disease, two misfolded protein diseases with a neuroinflammatory component. On the other hand, administration of ganglioside GM1 provides neuroprotection in both diseases and in several other models of neuronal insult. While most studies have focused on the role of endogenous gangliosides and the effects of exogenously administered GM1 in neurons, their contribution to microglia functions that are affected in neurodegenerative conditions is largely unexplored. Microglia are the immune cells of the brain and play important homeostatic functions in health and disease. In this study, we show that administration of exogenous GM1 exerts a potent anti-inflammatory effect on microglia activated with LPS, IL-1{beta} or upon phagocytosis of latex beads. These effects are partially reproduced by L-t-PDMP, a compound that stimulates the activity of the ganglioside biosynthetic pathway, while inhibition of ganglioside synthesis with GENZ-123346 increases microglial transcriptional response to LPS. We further show that administration of GM1 increases the uptake of apoptotic bodies and latex beads by microglia, as well as microglia migration and chemotaxis in response to ATP. On the contrary, decreasing microglial ganglioside levels results in a partial impairment in both microglial activities. Finally, increasing cellular ganglioside levels results in decreased expression and secretion of microglial brain derived neurotrophic factor (BDNF). Altogether, our data suggest that gangliosides are important modulators of microglia functions that are crucial to healthy brain homeostasis, and reveal that administration of ganglioside GM1 exerts an important anti-inflammatory activity that could be exploited therapeutically.

neuroscience↗

bioRxiv2018

Variants in the fetal genome near pro-inflammatory cytokine genes on 2q13 are associated with gestational duration

The duration of pregnancy is influenced by fetal and maternal genetic and non-genetic factors. We conducted a fetal genome-wide association meta-analysis of gestational duration, and early preterm, preterm, and postterm birth in 84,689 infants. One locus on chromosome 2q13 was associated with gestational duration; the association was replicated in 9,291 additional infants (combined P = 3.96 x 10-14). Analysis of 15,536 mother-child pairs showed that the association was driven by fetal rather than maternal genotype. Functional experiments showed that the lead SNP, rs7594852, alters the binding of the HIC1 transcriptional repressor. Genes at the locus include several interleukin 1 family members with roles in pro-inflammatory pathways that are central to the process of parturition. Further understanding of the underlying mechanisms will be of great public health importance, since giving birth either before or after the window of term gestation is associated with increased morbidity and mortality.

genetics↗