Biology subjects

Gillen, A.

Publications and source records attributed to Gillen, A..

5 recordsLinked to original sources

bioRxiv2024

A novel dataset of 2,362 equine fecal microbiomes from eight veterinary teaching hospital on three continents reveals dominant effects of geography, breed, and disease

Horses and other equids are reliant on the gut microbiome for health, and studies have reported associations between certain clinical conditions and features of the fecal microbiome. However, research to date on the equine fecal microbiome has often relied on small sample sizes collected from single and relatively localized geographic regions. Previous work largely employs single timepoint analyses, or horses selected based on limited health criteria. To address these issues and expand our understanding of the core microbiome in health, and the changes associated with adverse outcomes, the Equine Gut Group (EGG) has collected and performed 16S rRNA sequencing on 2,362 fecal samples from 1,190 healthy and affected horses. Here we present the EGG database and demonstrate its utility in characterizing the equine microbiome in health and acute gastrointestinal disease. The EGG 16S rRNA database is a valuable resource to study the equine microbiome and its role in equine health.

microbiology↗

bioRxiv2024

Allogenic platelet-rich plasma and platelet-rich plasma extracellular vesicles alter the proteome of tenocytes in an in vitro equine model of tendon inflammation: A pilot study

BackgroundTendon injuries are common in horses, often resulting in a high risk of reinjury. Hemoderivative therapeutics including platelet-rich plasma (PRP) show promise but outcomes vary due to inconsistent composition. PRP is rich in soluble growth factors and extracellular vesicles (EVs), the latter facilitate cell-to-cell communication by delivering biologically active cargo. This pilot study profiled the proteome of PRP and PRP-derived EVs and examined their effects on an equine tendon inflammatory model in vitro. MethodsPlasma was isolated via double centrifugation and PRP produced using a commercial filtration kit. EVs were isolated from PRP and plasma using differential ultracentrifugation and characterised with the Exoview Tetraspanin assay. Equine tenocytes were stimulated with interleukin 1{beta} and tumor necrosis factor , then treated with PRP or PRP-derived EVs. Proteomic analysis was conducted on cell lysates, PRP and PRP-EVs using data-dependent acquisition liquid chromatography-tandem mass spectrometry and the data analyzed using multivariate and univariate approaches. ResultsPRP contained 575 quantifiable proteins and PRP-derived EVs 209 proteins. When compared to plasma and plasma derived EVs respectively, PRP and PRP-EVs were enriched in proteins associated with cellular waste disposal and inhibition of lipid metabolism. Experimental factors (inflammatory stimulation and/or treatments) significantly affected the abundance of 18 proteins as expressed in equine tenocytes including col1a1 (col1a1) and sequestosome 1, associated with collagen metabolism and nuclear factor kappa B signaling. DiscussionThe findings from this study suggest PRP-derived EVs influence inflammatory tenocytes and may be crucial to the efficacy of PRP.

molecular biology↗

bioRxiv2023

Mesenchymal Stromal Cell secretome is affected by tissue source, donor age and sex.

Variation in Mesenchymal Stromal Cell (MSC) function depending on their origin is problematic, as it may confound clinical outcomes of MSC therapy. Current evidence suggests that the therapeutic benefits of MSCs is primarily attributed to secretion of various biologically active factors (secretome). However, the effect of donor characteristics on the MSC secretome composition remains largely unknown. Here, we examined the influence of donor age, sex and tissue source, on the protein profile of the equine MSC secretome. Initially, we used dynamic metabolic labelling with stable isotopes combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify secreted proteins in MSC conditioned media (CM). Seventy proteins were classified as classically-secreted based on the rate of isotope label incorporation into newly synthesised proteins released into the extracellular space. Next, we analysed CM of bone marrow- (n = 14) and adipose-derived MSCs (n = 16) with label-free LC-MS/MS proteomics. Clustering analysis of 314 proteins detected across all samples identified tissue source as the main factor driving variability in MSC CM proteomes. Linear modelling applied to the subset of 70 secreted proteins identified tissue-related difference in the abundance of 23 proteins. There was an age-related decrease in the abundance of two proteins (CTHRC1, LOX), which has been validated with western blot and enzymatic activity assay. There was limited evidence of sex-related differences in protein abundance. In conclusion, this study provides evidence that tissue source and donor age contribute to heterogeneity in the protein composition of MSC secretomes which may influence the effects of MSC-based cell therapy. Significance statementThis research shows for the first time that donor age can influence the proteins secreted by mesenchymal stromal cells (MSC), which is considered the main mechanism through which they mediate their biological actions. This information may improve our understanding of the variable outcomes observed in MSC clinical studies, as well as identify optimal sources and donor selection for specific clinical applications.

cell biology↗

bioRxiv2020

Prdm8 regulates pMN progenitor specification for motor neuron and oligodendrocyte fates by modulating Shh signaling response

Spinal cord pMN progenitors sequentially produce motor neurons and oligodendrocyte precursor cells (OPCs). Some OPCs differentiate rapidly as myelinating oligodendrocytes whereas others remain into adulthood. How pMN progenitors switch from producing motor neurons to OPCs with distinct fates is poorly understood. pMN progenitors express prdm8, which encodes a transcriptional repressor, during motor neuron and OPC formation. To determine if prdm8 controls pMN cell fate specification, we used zebrafish as a model system to investigate prdm8 function. Our analysis revealed that prdm8 mutant embryos have a deficit of motor neurons resulting from a premature switch from motor neuron to OPC production. Additionally, prdm8 mutant larvae have excess oligodendrocytes and a concomitant deficit of OPCs. Notably, pMN cells of mutant embryos have elevated Shh signaling coincident with the motor neuron to OPC switch. Inhibition of Shh signaling restored the number of motor neurons to normal but did not rescue the proportion of oligodendrocytes. These data suggest that Prdm8 regulates the motor neuron-OPC switch by controlling the level of Shh activity in pMN progenitors and also regulates allocation of oligodendrocyte lineage cell fates. Summary StatementPrdm8 regulates the timing of a motor neuron-oligodendrocyte switch and oligodendrocyte lineage cell identity in the zebrafish spinal cord.

developmental biology↗

bioRxiv2018

Dynamic temperature-sensitive A-to-I RNA editing in the brain of a heterothermic mammal during hibernation

RNA editing diversifies genomically encoded information to expand the complexity of the transcriptome. In ectothermic organisms, including Drosophila and Cephalopoda, where body temperature mirrors ambient temperature, decreases in environmental temperature lead to increases in A-to-I RNA editing and cause amino acid recoding events that are thought to be adaptive responses to temperature fluctuations. In contrast, endothermic mammals, including humans and mice, typically maintain a constant body temperature despite environmental changes. Here, A-to-I editing primarily targets repeat elements, rarely results in the recoding of amino acids and plays a critical role in innate immune tolerance. Hibernating ground squirrels provide a unique opportunity to examine RNA editing in a heterothermic mammal whose body temperature varies over 30{degrees}C and can be maintained at 5{degrees}C for many days during torpor. We profiled the transcriptome in three brain regions at six physiological states to quantify RNA editing and determine whether cold-induced RNA editing modifies the transcriptome as a potential mechanism for neuroprotection at low temperature during hibernation. We identified 5,165 A-to-I editing sites in 1,205 genes with dynamically increased editing after prolonged cold exposure. The majority (99.6%) of the cold-increased editing sites are outside of previously annotated coding regions, 82.7% lie in SINE-derived repeats, and 12 sites are predicted to recode amino acids. Additionally, A-to-I editing frequencies increase with increasing cold-exposure demonstrating that ADAR remains active during torpor. Our findings suggest that dynamic A-to-I editing at low body temperature may provide a neuroprotective mechanism to limit aberrant dsRNA accumulation during torpor in the mammalian hibernator.

genomics↗