Biology subjects

Tong, O.

Publications and source records attributed to Tong, O..

6 recordsLinked to original sources

bioRxiv2026

Citrate-Based Hydrogels Promote Closure of Infected Diabetic Wounds

Diabetic foot ulcers (DFUs) are a significant threat to the quality of life for individuals with diabetes, affecting approximately 1.6 million patients in the US, as of 2023. When these wounds do not heal and become chronic wounds, they can become infected and increase the risk of digit and/or lower limb amputation. Therefore, there is a critical need for therapies that promote wound closure in the presence and absence of infection. We have previously reported the potential benefits of the thermoresponsive citrate-based macromolecule poly(polyethylene glycol citrate-co-N-isopropylacrylamide) (PPCN) in diabetic rodent and swine models of non-infected full thickness dermal wounds. In this study, we compared four PPCN formulations (PPCN, PPCN-CMOF, A5G81-PPCN, and A5G81-PPCN-CMOF), which are functionalized with the laminin-derived cell adhesion peptide A5G81 and/or contain entrapped copper metal-organic framework nanoparticles (CMOF) designed to release Cu2+ slowly, in diabetic mice with wounds infected with S. aureus. In infected wounds, all four formulations significantly improved cumulative closure relative to saline (adjusted p = 0.002-0.021). In non-infected wounds, only PPCN-CMOF significantly improved cumulative closure relative to saline (p = 0.046), although all four formulations reached [≥]95% closure earlier than saline (adjusted p = 0.009-0.045). In vitro, the CMOF-containing formulations produced the highest bacterial killing (90% for A5G81-PPCN-CMOF and 84% for PPCN-CMOF), whereas A5G81-PPCN and PPCN reduced bacterial colonies by 76% and 59%. PPCN modification with A5G81 and/or CMOF increased endothelial mesh formation in vitro. In vivo, PPCN-based formulations increased granulation tissue thickness and, depending on formulation and infection status, vascular marker expression. These results suggest that PPCN and PPCN formulations containing CMOF and/or A5G81 are a potentially viable technology that can be added to the wound care toolbox to accelerate healing of diabetic foot ulcers in the presence of infection. These findings support further investigation of PPCN as an instructive pro-regenerative biomaterial in a preclinical large animal model.

bioengineering↗

bioRxiv2026

A Pro-Regenerative Petroleum Jelly-Based, Copper-Doped Bioactive Glass Ointment for Impaired Wound Healing in Metabolic Syndrome

Chronic wound healing is often impaired in conditions such as metabolic syndrome, requiring effective therapeutic interventions to promote tissue regeneration and repair. In this study, we evaluated the wound healing potential of petroleum jelly (P Jelly)-based bioactive glass ointments (PBGCu) with varying copper concentrations (0, 1, and 3 wt%) in both in vitro and in vivo models of wound healing. PBGCu formulations demonstrated high biocompatibility with human dermal fibroblasts (HDF) and human umbilical vein endothelial cells (HUVEC). Additionally, PBGCu ointments exhibited strong antibacterial activity against Staphylococcus aureus, suggesting their utility for the care of chronic wounds. In both metabolic syndrome mouse and pig models, PBGCu3-treated wounds showed significantly faster wound closure, enhanced epithelial regeneration, and increased dermal thickness compared to saline and P Jelly controls. Histological analysis also revealed 50% increased vascularization (p < 0.0001) and a 90% reduction in scar formation (p < 0.0001) in PBGCu3-treated wounds. These findings show that PBGCu formulations, especially at 3 wt% copper concentration, significantly improve wound healing by promoting epithelial regeneration, dermal tissue formation, and vascularization, while also offering antibacterial protection. The sustained Cu2+ ions release from PBGCu ointments provides long-term support for tissue regeneration, positioning this ointment composition as a promising therapeutic tool for chronic wound management. Future studies will focus on elucidating the underlying mechanisms and evaluating the therapeutic efficacy of PBGCu formulations in infected wounds. HighlightsO_LIDeveloped a Petroleum Jelly-based copper-doped bioactive glass ointment (PBGCu) enabling sustained and controlled Cu{superscript 2} ion release. C_LIO_LIPBGCu significantly accelerated wound closure and improved epithelial and dermal tissue regeneration. C_LIO_LIPBGCu enhanced hair follicle regeneration and tissue remodeling in full-thickness wounds. C_LIO_LIValidated therapeutic efficacy in both mouse and pig models that support translational relevance. C_LIO_LIOffers a simple, low-cost, and clinically adaptable topical formulation for metabolic syndrome-related wound complications. C_LI

bioengineering↗

bioRxiv2024

Defining the genetic determinants of CD8+ T cell receptor repertoire in the context of immune checkpoint blockade

CD8+ T cells play a central role in the cancer response to immune checkpoint blockade (ICB) treatment, with activity predicated upon antigen recognition by the associated T cell receptor (TCR) repertoire. The contribution of genetic variation to this in cancer treatment is under-explored. We have conducted a genome-wide and human leukocyte antigen (HLA)-focused analysis of CD8+ T cell TCR repertoire to identify genetic determinants of variable gene (V-gene) and CDR3 K-mer usage from samples taken prior to and after ICB treatment (n=250). We find 11 genome-wide significant cis associations and 10 trans associations, primarily to the HLA, with V-gene usage meeting permuted P-value thresholds. Notably, TCR clones containing V-genes associated with HLA were less likely to be persistent across treatment. In a single-cell experiment, we find cells with HLA-matched TCR clones have increased tumor reactivity expression profiles and patients with HLA-matched TCR clones have improved overall survival. Our work indicates a complex relationship between genotype and TCR repertoire in the context of treatment with ICB, which has novel implications for understanding determinants of treatment response and patient outcomes. One Sentence SummaryTCR repertoire is strongly associated with specific HLA alleles in cancer patients, but immune checkpoint blockade influences this association.

genetics↗

bioRxiv2023

Characterisation of the genetic determinants of context specific DNA methylation in primary monocytes

DNA methylation (DNAm) has pervasive effects on gene expression and associations with ageing-related traits. Here we describe monocyte DNAm responses to inflammatory stimuli across 192 individuals. We find that, unlike the similarly widespread changes in gene expression elicited by LPS and IFN{gamma}, DNAm is markedly more sensitive to LPS. Exposure to LPS caused differential methylation at 20,858 immune-modulated CpGs (imCpGs) which display distinct genomic localisation and transcription factor usage, dependent upon whether methylation is lost or gained. Demethylated imCpGs are profoundly enriched for enhancers, and are over-represented by genes implicated in human diseases, most notably cancer. We find LPS-induced demethylation follows hydroxymethylation and for most sites the degree of demethylation correlates with baseline signal. Notably, we find LPS exposure triggers gain in epigenetic age by approximately 6 months, identifying a potential cause of accelerated epigentic aging which has diverse negative health associations. Finally, we explore the effect of genetic variation on LPS-induced changes in DNAm, identifying 209 imCpGs under genetic control. Exploring shared causal loci between LPS-induced DNAm responses and human disease traits highlights examples of human disease associated loci that also modulate imCpG formation. In summary, our findings suggest innate immune activity continually remodels DNAm in a highly punctate, enhancerenriched fashion that is under tight genetic control and predominantly involves genes commonly mutated in cancer.

genetics↗

bioRxiv2023

Deep sequencing of the T cell Receptor reveals common and reproducible CD8+ signatures of response to checkpoint immunotherapy

Immune checkpoint blockade (ICB) has markedly improved outcomes across a range of tumours, including metastatic melanoma (MM). However, peripheral biomarkers of response remain lacking and underlying mechanisms of action incompletely described. A number of studies have demonstrated the value of T cell receptor (TCR) repertoire analysis in determining associations with response, however identifying key groups of T cells based on their TCR usage has remained elusive. Here we performed deep sequencing of the TCR of CD8+ T cells isolated from peripheral blood of patients receiving ICB for MM (n=91) at multiple time points, along with healthy control samples (n=42) and resected tumour specimens (from n=7 patients). Using the GLIPH2 algorithm to cluster TCR based on putative shared antigen specificity, we describe groups of TCR which expand post-ICB in responding patients which we term Emergent Responder (ER) clones. We find that these ER clones are typically large and of a memory phenotype, with increased expression of genes encoding cytotoxic proteins. Analysis of tumours resected in advance of ICB demonstrates ER clones are enriched and expanded within the tumour compared to the periphery at pre-treatment. Significantly, we note the proportion of the peripheral repertoire occupied by ER clones strongly correlates with long-term clinical response. Clinical outcome further associated with HLA type and, crucially, can be validated across replication and independent datasets. This work provides the first-in-kind description of TCR-defined CD8+ T cells that mediate the response to ICB in MM, demonstrating the prognostic utility of the peripheral immune repertoire with potential widespread therapeutic and prognostic applications.

immunology↗

bioRxiv2020

Immune Checkpoint Blockade induces peripheral cytotoxicity and persistence of large effector CD8+ T cell clones

Immune checkpoint blockers (ICB) exert their anti-cancer effects via CD8+ T cells, although how responses vary over sub-populations and across clones is incompletely understood. We performed single-cell RNA-sequencing of CD8+ T cells and their receptors pre- and post-ICB across eight patients, integrating results with bulk-sequencing data (n=209). We identify seven subsets with divergent responses to ICB, finding the effector cluster demonstrates the most pronounced changes. Likewise, transcriptomic response to ICB relates to clone size, with large clones demonstrating increased numbers of regulated genes of higher immunological pertinence. Cytotoxic effector clones were more likely to persist long-term following ICB and overlapped with public tumour-infiltrating lymphocyte clonotypes. Notably, pre-treatment CD8+ cytotoxicity associated with progression-free survival, highlighting the importance of the baseline CD8+ immune landscape in long-term response. This work further advances understanding of the molecular determinants of ICB response and assists in the search for peripheral prognostic biomarkers. ONE SENTENCE SUMMARYUsing single-cell and bulk RNA sequencing we explore checkpoint immunotherapy activity on peripheral CD8+ T cells in metastatic melanoma; demonstrating that cell subset and clone size determine gene expression responses to treatment, and that pre-treatment cytotoxicity and clonality of peripheral CD8+ T cells is clinically prognostic.

immunology↗