Biology subjects

Frost, K.

Publications and source records attributed to Frost, K..

4 recordsLinked to original sources

bioRxiv2026

Translational toolkit for reproducible, cross-study profiling of human ageing hallmarks in human blood and tissue

BackgroundAgeing is a complex, multi-dimensional process, underpinned by interacting biological hallmarks that collectively contribute to functional decline and increased susceptibility to disease. While considerable progress has been made in delineating individual ageing pathways, translation into human studies has been hindered by methodological heterogeneity and a lack of standardised, multi-system approaches. Here, we describe a validated, high-resolution toolkit for the simultaneous quantification of multiple ageing hallmarks in clinically accessible human samples, encompassing cellular senescence, immune ageing, inflammation, mitochondrial function, mTOR signalling, autophagy, genomic instability, and stem cell exhaustion. MethodsBlood (25ml) was obtained from young and aged donors (26-81y). Deep immunophenotyping was performed using a novel 30-colour spectral flow cytometry panel. T-cell mTOR activation and autophagic flux were assessed by flow cytometry. Metabolic flux was measured by Seahorse. From whole blood (4 ml), muscle, and adipose tissue (AT) (obtained during elective hip arthroplasty) RNA, DNA, AT stem cells, and myoblasts were isolated. DNA copy number and senescent cell burden were assessed by q-PCR and SA-{beta}-gal staining, respectively. FindingsUtilising this toolkit, we identified pronounced age-related immune remodelling, increased senescent T-cell burden, diminished mitochondrial capacity and altered mTOR-autophagy signalling between healthy young and aged donors. Furthermore, metabolism was significantly affected by anti-coagulant and freezing sample before analysis. InterpretationThis integrated platform provides a foundation for reproducible, cross-study analyses and facilitates translational investigation of interventions targeting health-span extension. FundingWellcome Leap Dynamic Resilience program (co-funded by Temasek Trust).

immunology↗

bioRxiv2026

Characterization of Atypical Ebola Virus Disease in Ferrets

Ebola virus (EBOV) typically results in a severe--and often lethal--acute disease. However, increasing evidence suggests that EBOV can persist in certain immune-privileged tissues, which may then serve as reservoirs for the later reemergence of EBOV and disease recrudescence. Here, we report atypical EVD recrudescence in a ferret model inoculated with an otherwise lethal dose of EBOV and treated with low doses of a highly potent monoclonal antibody cocktail. Among 32 antibody-treated ferrets, 14 animals survived, while 8 succumbed to acute EVD within about 5-8 days. The remaining 10 animals succumbed to atypical EVD between 12 and 18 days post-infection (DPI) despite having shown no, or very minor, signs of illness during the acute phase of disease. While viremia disappeared by 14 DPI in most animals that succumbed to atypical EVD, it rebounded modestly just prior to death. Unlike animals that died of acute EVD, those that died of atypical EVD showed only a moderate systemic inflammatory response and few signs of organ dysfunction, in line with low levels of virus in the liver and spleen. Interestingly, however, ferrets that died of atypical EVD showed high levels of virus in the brain, consistent with increased markers of inflammation in the central nervous system and significant pathological changes, including a breakdown in the blood-brain barrier and severe meningoencephalitis. Not only does this study shed important light on the atypical and underappreciated manifestations of EVD, but it also establishes the ferret as a valuable model of EBOV persistence and recrudescence. AUTHOR SUMMARYOver the last several years, it has become increasingly apparent that Ebola virus is capable of persisting in survivors and, occasionally, reemerging to cause a recrudescent disease that is often distinct from the acute illness and characterized by neurological involvement. Since nearly all existing Ebola virus animal models are uniformly lethal, it has been difficult to understand the processes that lead to persistence and atypical manifestations of disease. In this study, we describe a late-onset, atypical Ebola virus disease in ferrets that was characterized by high levels of virus in the brain and significant markers of brain inflammation. Our comprehensive analysis of the pathogenic processes that contributed to this disease not only provides critical insight into Ebola virus persistence and recrudescence, but it also establishes the ferret as the first tractable model for investigating these atypical outcomes.

microbiology↗

bioRxiv2024

Non-targeted screening method for detecting temporal shifts in spectral patterns of Methicillin Resistance Staphylococcus aureus and post-hoc description of peak features

Non-targeted methods (NTMs) using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) show promise in bacterial resistance detection, yet temporal variations in spectral features pose significant challenges. These proteomic patterns, which characterize bacterial phenotypes and pathological functions, may vary over time due to bacterial adaptation, virulence, or resistance mechanisms, resulting in large prediction uncertainties and potentially degrading NTM performance. We present a comprehensive screening method to detect temporal changes in MALDI-TOF spectral patterns, demonstrated using methicillin-resistant and -susceptible Staphylococcus aureus (MRSA/MSSA) isolates collected over several years. Our approach combines convolutional neural networks (CNN) with statistical methods, including significance testing, kernel density estimation, and receiver operating characteristics for dataset shift detection. We employ Gradient-weighted Class Activation Mapping (Gradcam) for post-hoc feature description, enabling biochemical characterization of temporal changes. This analysis reveals crucial insights into the dynamic relationship between spectral data patterns over time, addressing key challenges in developing robust NTMs for routine applications.

microbiology↗

bioRxiv2021

Single immunization with recombinant ACAM2000 vaccinia viruses expressing the spike and the nucleocapsid proteins protect hamsters against SARS-CoV-2 caused clinical disease

Increasing cases of SARS-CoV-2 breakthrough infections from immunization with predominantly spike protein based COVID-19 vaccines highlight the need for alternative vaccines using different platforms and/or antigens. In this study, we expressed SARS-CoV-2 spike and nucleocapsid proteins in a novel vaccinia virus ACAM2000 platform (rACAM2000). Following a single intramuscular immunization, the rACAM2000 co-expressing the spike and nucleocapsid proteins induced significantly improved protection against SARS-CoV-2 challenge in comparison to rACAM2000 expressing the individual proteins in a hamster model, as shown by reduced weight loss and quicker recovery time. The protection was associated with reduced viral loads, increased neutralizing antibody titre and reduced neutrophil-to-lymphocyte ratio. Thus, our study demonstrates that the rACAM2000 expressing a combination of the spike and nucleocapsid antigens is a promising COVID-19 vaccine candidate and further studies will investigate if the rACAM2000 vaccine candidate can induce a long lasting immunity against infection of SARS-CoV-2 variants of concern.

microbiology↗