The effect of myeloablative radiation on urinary bladder mast cells Jessica Smith, Jonathan Kah Huat Tan, Christie Short, Helen O’Neill, Christian Moro Scientific Reports, 2024 Radiation-induced cystitis is an inflammatory condition affecting the urinary bladder, which can develop as a side effect of abdominopelvic radiotherapy, specifically external-beam radiation therapy or myeloablative radiotherapy. A possible involvement of mast cells in the pathophysiology of radiation-induced cystitis has been indicated in cases of external-beam radiation therapy; however, there is no evidence that these findings apply to the myeloablative aetiology. As such, this study investigated potential changes to urinary bladder mast cell prevalence when exposed to myeloablative radiation. Lethally irradiated C57BL/6J mice that received donor rescue bone marrow cells exhibited an increased mast cell frequency amongst host leukocytes 1 week following irradiation. By 4 weeks, no significant difference in either frequency or cell density was observed. However mast cell diameter was smaller, and a significant increase in mast cell number in the adventitia was observed. This study highlights that mast cells constitute a significant portion of the remaining host leukocyte population following radiation exposure, with changes to mast cell distribution and decreased cell diameter four weeks following radiation-induced injury.
Genome-wide association analyses of ovarian cancer patients undergoing primary debulking surgery identify candidate genes for residual disease Dhanya Ramachandran, Jonathan P. Tyrer, Stefan Kommoss, Anna DeFazio, Marjorie J. Riggan, et al. Npj Genomic Medicine, 2024 Survival from ovarian cancer depends on the resection status after primary surgery. We performed genome-wide association analyses for resection status of 7705 ovarian cancer patients, including 4954 with high-grade serous carcinoma (HGSOC), to identify variants associated with residual disease. The most significant association with resection status was observed for rs72845444, upstream of MGMT, in HGSOC (p = 3.9 × 10−8). In gene-based analyses, PPP2R5C was the most strongly associated gene in HGSOC after stage adjustment. In an independent set of 378 ovarian tumours from the AGO-OVAR 11 study, variants near MGMT and PPP2R5C correlated with methylation and transcript levels, and PPP2R5C mRNA levels predicted progression-free survival in patients with residual disease. MGMT encodes a DNA repair enzyme, and PPP2R5C encodes the B56γ subunit of the PP2A tumour suppressor. Our results link heritable variation at these two loci with resection status in HGSOC.
Cytocompatibility of electrospun poly-L-lactic acid membranes for Bruch's membrane regeneration using human embryonic stem cell-derived retinal pigment epithelial cells Naghmeh Abbasi, Helen O'Neill Journal of Biomedical Materials Research Part A, 2024 Cell replacement therapy is under development for dry age‐related macular degeneration (AMD). A thin membrane resembling the Bruch's membrane is required to form a cell‐on‐membrane construct with retinal pigment epithelial (RPE) cells. These cells have been differentiated from human embryonic stem cells (hESCs) in vitro. A carrier membrane is required for cell implantation, which is biocompatible for cell growth and has dimensions and physical properties resembling the Bruch's membrane. Here a nanofiber electrospun poly‐L‐lactic acid (PLLA) membrane is tested for capacity to support cell growth and maturation. The requirements for laminin coating of the membrane are identified here. A porous electrospun nanofibrous PLLA membrane of ∼50 nm fiber diameter was developed as a prototype support for functional RPE cells grown as a monolayer. The need for laminin coating applied to the membrane following treatment with poly‐L‐ornithine (PLO), was identified in terms of cell growth and survival. Test membranes were compared in terms of hydrophilicity after laminin coating, mechanical properties of surface roughness and Young's modulus, porosity and ability to promote the attachment and proliferation of hESC‐RPE cells in culture for up to 8 weeks. Over this time, RPE cell proliferation, morphology, and marker and gene expression, were monitored. The functional capacity of cell monolayers was identified in terms of transepithelial electrical resistance (TEER), phagocytosis of cells, as well as expression of the cytokines, vascular endothelial growth factor (VEGF) and pigment epithelium‐derived factor (PEDF). PLLA polymer fibers are naturally hydrophobic, so their hydrophilicity was improved by pretreatment with PLO for subsequent coating with the bioactive protein laminin. They were then assessed for amount of laminin adsorbed, contact angle and uniformity of coating using scanning electron microscopy (SEM). Pretreatment with 100% PLO gave the best result over 10% PLO treatment or no treatment prior to laminin adsorption with significantly greater surface stiffness and modulus. By 6 weeks after cell plating, the coated membranes could support a mature RPE monolayer showing a dense apical microvillus structure and pigmented 3D polygonal cell morphology. After 8 weeks, PLO (100%)‐Lam coated membranes exhibited the highest cell number, cell proliferation, and RPE barrier function measured as TEER. RPE cells showed the higher levels of specific surface marker and gene expression. Microphthalmia‐associated transcription factor expression was highly upregulated indicating maturation of cells. Functionality of cells was indicated by expression of VEGF and PEDF genes as well as phagocytic capacity. In conclusion, electrospun PLLA membranes coated with PLO‐Lam have the physical and biological properties to support the distribution and migration of hESC‐RPE cells throughout the whole structure. They represent a good membrane candidate for preparation of hESC‐RPE cells as a monolayer for implantation into the subretinal space of AMD patients.
Exploring the regenerative capacity of the spleen following irradiation Christie T. M. Short, Helen C. O’Neill, Jonathan K. H. Tan Frontiers in Hematology, 2024 IntroductionHaematopoietic stem cell transplantation (HSCT) is commonly used to treat patients with haematological disorders. Myeloablative conditioning is an important preparation for patients receiving haematopoietic stem cells (HSC) or haematopoietic stem and progenitor cells (HSPC). While widely successful, HSCT is still associated with high rates of mortality. The recovery time between complete myeloablation and haematopoietic recovery is a large factor in the recovery rate. Successful engraftment of HSC is also directly correlated with the number of HSC niches available. This highlights the importance of the haematopoietic niche and its recovery from myeloablation as an important therapeutic target.MethodsThis murine model study specifically considers changes in spleen tissue architecture and cellular composition involving stromal and vascular cells that occur following lethal irradiation.ResultsSpleen recovered fully between 4- and 8-weeks after irradiation due to reconstitution by HSPC from bone marrow. Specific temporal changes in spleen architecture were identified, and these were linked to the cell types that constitute the white pulp, red pulp and marginal zones. Mesenchymal stromal cells returned before endothelial cells, and reticular cell types recovered more quickly in spleen following irradiation. Losses in gp38+ fibroblastic reticular cells and MAdCAM-1+ marginal reticular cells were associated with loss of the white pulp in the first 4 weeks following irradiation. White pulp was restored following recovery of supporting reticular cells.DiscussionThis study tests how spleen regeneration following a lethal dose of irradiation can be influenced by co-infusion of bone marrow HSPC together with either neonatal spleen stromal cells, or cells of the stromal STX3 line. Both the infusion of neonatal spleen stromal cells and STX3 stromal cells hastened recovery of both mesenchymal and vascular compartments. Following neonatal spleen stromal cell infusion, endothelial cells increased early, but a delay in structural reformation of distinct red and white pulp areas was found. Results from this study show that spleen regeneration can be influenced and even hastened through cellular therapy. Neonatal spleen stromal cells, co-infused together with HSPC following irradiation conditioning, represent a potential therapeutic opportunity for hastening spleen regeneration.
GENOME EDITING IN HUMAN REPRODUCTION Helen C. O'Neill Textbook of Assisted Reproductive Techniques Volume 1 Laboratory Perspectives Sixth Edition, 2023
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