Biology subjects

O'Driscoll, L.

Publications and source records attributed to O'Driscoll, L..

8 recordsLinked to original sources

bioRxiv2025

Extracellular Vesicles-Mediated Crosstalk in Bone: miR-150-5p as a Mechanosensitive Inhibitor of Osteoclastogenesis

Bone is a dynamic tissue that is constantly remodelling via a tightly controlled balance between formation and resorption. However, when osteoclast-mediated resorption exceeds formation, it can lead to net bone loss and the development of osteoporosis. Osteoclastogenesis is regulated by local environmental cues, including paracrine factors released by resident cell populations. Extracellular vesicles (EVs) have recently emerged as key mediators of paracrine communication, though their role in osteoclastogenesis remains underexplored. Therefore, this study investigated how resident mesenchymal-derived bone cells and their secreted EVs modulate osteoclastogenesis, and delineate the signalling factors mediating this anti-catabolic communication. We demonstrate that the secretome of mesenchymal-derived bone cells inhibit osteoclast differentiation to differing degrees depending on the stage of lineage commitment and on the mechanical environment, and demonstrate that this inhibition is mediated via the release of EVs. In addition, we identified the terminally differentiated osteocyte as the optimal parent cell for the production of anti-catabolic EVs and demonstrated the importance EV dosage. Finally, we show that mechanosensitive miR-150-5p is packaged within osteocyte-derived EVs and inhibits osteoclast differentiation. Taken together, this study identifies mechanically-activated osteocyte derived EVs and miR-150-5p as key regulators of osteoclastogenesis and novel molecular therapies for skeletal pathologies.

bioengineering↗

bioRxiv2025

Mechanically activated bone cell derived extracellular vesicles regulate angiogenesis in a manner that is dependent on the stage of lineage commitment

Bone regeneration requires a finely tuned interplay between osteogenesis and angiogenesis. While current treatments such as auto/allografts, provide support, they often fail to promote adequate vascularisation necessary for complete repair. Extracellular vesicles (EVs), as mediators of intercellular communication, have emerged as promising acellular nanotechnologies for tissue regeneration due to their bioactive cargo and low immunogenicity. Mechanical stimulation, a known enhancer of bone cell function, can modulate EV cargo and potentially improve regenerative efficacy. In this study, we investigated how mechanical stimulation, and the stage of mesenchymal lineage commitment influence the angiogenic potential of secretomes and EVs derived from mesenchymal stromal/stem cells, osteoblasts, and osteocytes. Our findings reveal that both cell mechanical stimulation and their differentiation stage significantly modulate the angiogenic properties of the resulting EVs. Among the tested conditions, mechanically-stimulated osteocyte-derived EVs demonstrate superior angiogenesis, promoting endothelial cell migration, tube formation, and CD31 expression. These effects were further validated in a pre-clinical ex ovo chick chorioallantoic membrane assay, where robust neovascularisation was observed. This work highlights the critical role of both mechanical cues and cell differentiation stage in regulating the angiogenic capacity of EVs and proposes mechanically activated osteocyte-derived EVs as a novel pro-angiogenic nanotherapeutic for bone repair.

bioengineering↗

bioRxiv2025

AGR2, a potential prognostic and predictive biomarker and therapeutic to overcome drug resistance in HER2-overexpressing cancer

The development of resistance to HER2-targeted drugs is common. Neratinib, an orally delivered cost effective drug is showing great promise for patients with HER2-overexpressing tumours but, unfortunately, for many the development of resistance is inevitable. In this study spanning novel pairs of cell line models and data from patients samples, we used a broad range of methodologies including mass-spectrometry-based quantitative proteomics, ectopic gene expression, RT-qPCR, immunoblotting, cytotoxicity, proliferation, invasion, and migration assays. We found loss of anterior gradient protein 2 (AGR2) to be prognostic for poor overall survival for patients with HER2-overexpressing tumours, in contrast to what has been reported for estrogen-positive breast cancer. Additionally, we discovered that loss of AGR2 is not only associated with neratinb-resistance, but that its restoration by ectopic AGR2 expression in neratinib-resistance cells partly restores their drug sensitivity. Furthermore, we established that keys metastatic phenotypic traits acquired with neratinib-resistance were blocked by ectopic AGR2 expression in the cells. Taken together, our results show that AGR2 has potential as a prognostic biomarker for outcome from HER2-overexpressing cancer; a predictive biomarker for resistance/response to neratinib; and a potential therapeutic protein for helping restore sensitivity to neratinib and overcoming aggressive cellular traits associated with cancer metastasis. Statement of SignificanceAGR2 loss in HER2-overexpressing cancer is prognostic for poor outcome and predictive for HER2-targeted drug-resistance, with AGR2 re-introduction helping restore drug sensitivity and overcoming phenotypic characteristics key to metastasis.

cancer biology↗

bioRxiv2024

A comparative study of circulating tumor cell isolation and enumeration technologies in lung cancer

Circulating tumor cells (CTCs) have potential as diagnostic, prognostic and predictive biomarkers in solid tumors. Despite FDA approval of CTC devices in various cancers, their rarity and limited comparison between analysis methods hinder their clinical integration for lung cancer. This study aimed to evaluate five CTC isolation technologies using a standardized spike-in protocol: the CellMag (EpCAM-based enrichment), EasySep and RosetteSep (blood cell depletion), and the Parsortix(R) PR1 and next generation Parsortix(R) Plus (PX+) (size-based enrichment). The Parsortix(R) systems were also evaluated for any difference in recovery rates between cell harvest versus in- cassette staining. Healthy donor blood (5 mL) was spiked with 100 fluorescently labeled H1975 lung adenocarcinoma cell line, processed through each system and the isolation efficiency was calculated. All tested systems yielded discordant recovery rates with the CellMag having the highest mean recovery (70 {+/-} 14%) followed by the PR1 (in-cassette staining) with a recovery of 49 {+/-} 2% while the EasySep had the lowest recovery (18 {+/-} 8%). The CellMag and Parsortix(R) PR1 may have potential clinical applications for lung cancer patients, albeit needing further optimization and validation.

cancer biology↗

bioRxiv2023

Mechanically activated bone cells drive vessel formation via an extracellular vesicle mediated mechanism

Blood vessel formation is an important initial step for bone formation during development as well as during remodelling and repair in the adult skeleton. This results in a heavily vascularized tissue where endothelial cells and skeletal cells are constantly in crosstalk to facilitate homeostasis, a process that is mediated by numerous environment signals, including mechanical loading. Breakdown in this communication can lead to disease and/or poor fracture repair. Therefore, this study aimed to determine the role of mature bone cells in regulating angiogenesis, how this is influenced by a dynamic mechanical environment, and understand the mechanism by which this could occur. Herein, we demonstrate that both osteoblasts and osteocytes coordinate endothelial cell proliferation, migration, and blood vessel formation via a mechanically dependent paracrine mechanism. Moreover, we identified that this process is mediated via the secretion of extracellular vesicles (EVs), as isolated EVs from mechanically stimulated bone cells elicited the same response as seen with the full secretome, while the EV depleted secretome did not elicit any effect. Despite mechanically activated bone cell derived EVs (MA-EVs) driving a similar response to VEGF treatment, MA-EVs contain minimal quantities of this angiogenic factor. Lastly, a miRNA screen identified mechanoresponsive miRNAs packaged within MA-EVs which are linked with angiogenesis. Taken together, this study has highlighted an important mechanism in osteogenic-angiogenic coupling in bone and has identified the mechanically activated bone cell derived EVs as a therapeutic to promote angiogenesis and potentially bone repair.

bioengineering↗

bioRxiv2021

Mechanically Activated Extracellular Vesicle Functionalised Melt Electrowritten Materials for Bone Regeneration: A Mechano-Biomimetic Scaffold

1Mechanobiological cues arising directly via tissue/scaffold mechanics or indirectly via mechanically activated cell secretomes represent potent stimuli that mediate cell behaviour and tissue adaptation. Exploiting these cues in regeneration strategies holds great promise for tissue repair. In this study, we harness indirect biophysical cues originating from osteocytes in a combination with direct biophysical cues from Melt ElectroWritten (MEW) scaffolds to form a single engineered construct with the aim of synergistically enhancing osteogenesis. The secretome of mechanically activated osteocytes was collected within conditioned media (CM) and extracellular vesicles (EV) were subsequently isolated. Building on MEW micro-fibrous scaffolds with controlled microarchitecture and mineral nanotopography optimised for bone repair, a protocol was developed to functionalise these materials with CM or EVs. Human MSC proliferation was enhanced in both CM and EV functionalised scaffolds. EV functionalised scaffolds were further found to significantly enhance MSC osteogenesis, with enhanced alkaline phosphatase expression, collagen production, and mineralisation compared to control scaffolds. Furthermore, enhanced formation of mineralised nodules was identified in EV functionalised materials. Combining direct biophysical cues provided by the fibrous architecture/mineral nanotopography with the indirect cues provided by EVs, these constructs hold great promise to enhance the repair of damaged bone in a physiologically relevant manner.

bioengineering↗

bioRxiv2020

Optimisation and comparison of orthogonal methods for separation and characterisation of extracellular vesicles to investigate how representative infant milk formula is of milk

This study aimed to separate and characterise extracellular vesicles (EV) from infant milk formula (IMF) and skim milk (SM), to determine how representative the EV content of IMF is to SM. Contaminant casein micelles, due to their abundance and overlapping size, were removed followed by either differential ultracentrifugation (DUC) or gradient ultracentrifugation (GUC). Characterisation included BCA, SDS-PAGE, nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), immunoblotting, and imaging flow cytometry (IFCM). NTA reported significantly reduced concentrations of EVs/particles in IMF versus SM; TEM showed intact SM-derived EVs to sparse and disrupted EV-like structures in IMF. Compared to IMF, noticeably stronger bands for EV biomarkers were observed by immunoblotting in SM, indicating compromised EV proteins in IMF; also supported by IFCM. Altogether, we established that EVs are substantially compromised during IMF processing. Furthermore, an optimised method combining acid pre-treatment and GUC for EV separation from milk products has been established.

molecular biology↗

bioRxiv2019

Human bone marrow mesenchymal stem/stromal cell behaviour is coordinated via mechanically activated osteocyte-derived extracellular vesicles

Osteocytes are mechanosensitive cells that are believed to play a fundamental role in coordinating bone mechanoadaptation via the secretion of paracrine factors. However, the exact mechanisms by which osteocytes relay mechanical signals to effector cells is poorly understood. In this study, we demonstrated that osteocytes subjected to a physiologic fluid shear secrete a distinct collection of factors that significantly enhance human MSC recruitment and osteogenesis. Utilising proteomics we generated an extensive map of proteins within the mechanically activated osteocyte secretome, identifying numerous paracrine factors that are modified by mechanical stimulation. Moreover, we identified the presence of extracellular vesicles (EVs) and further demonstrated that these mechanically activated osteocyte derived EVs (MAEVs) coordinate human MSCs recruitment and osteogenesis. This indicates that mechanical conditioning of parent cells can modify EVs and demonstrates the pro-osteogenic potential of MAEVs as a cell-free therapy to enhance bone regeneration and repair in diseases such as osteoporosis.

physiology↗