Biology subjects

Scarfe, L.

Publications and source records attributed to Scarfe, L..

3 recordsLinked to original sources

bioRxiv2023

Salmonella cancer therapy metabolically disrupts tumours at the collateral cost of T cell immunity

Bacterial cancer therapy (BCT) is a promising therapeutic for solid tumours. Salmonella enterica Typhimurium (STm) is well-studied amongst bacterial vectors due to advantages in genetic modification and metabolic adaptation. A longstanding paradox is the redundancy of T cells for treatment efficacy; instead, STm BCT depends on innate phagocytes for tumour control. Here, we used distal T cell receptor (TCR) reporter mice (Nr4a3-Tocky-Ifng-YFP) and a colorectal cancer (CRC) model to interrogate T cell activity during BCT with attenuated STm. We found that colonic TILs exhibited a variety of activation defects, including IFN-{gamma} production decoupled from TCR signalling, decreased polyfunctionality and reduced TCM formation. Modelling of T-cell-tumour interactions with a tumour organoid platform revealed an intact TCR signalosome, but paralysed metabolic reprogramming due to inhibition of the master metabolic controller, c-Myc. Restoration of c-Myc by deletion of the bacterial asparaginase ansB reinvigorated T cell activation, but at the cost of decreased metabolic control of the tumour by STm. This work shows for the first time that T cells are metabolically defective during BCT, but also that this same phenomenon is inexorably tied to intrinsic tumour suppression by the bacterial vector.

immunology↗

bioRxiv2019

Murine models of renal ischaemia reperfusion injury: An opportunity for refinement using non-invasive monitoring methods

BackgroundRenal Ischaemia Reperfusion Injury (R-IRI) can cause Acute Kidney Injury (AKI) and Chronic Kidney Disease (CKD), resulting in significant morbidity and mortality. To understand the underlying mechanisms, reproducible small-animal models of AKI and CKD are needed. We describe how innovative technologies for measuring kidney function non-invasively in small rodents allow successful refinement of the R-IRI models, and offer the unique opportunity to monitor longitudinally in individual animals the transition from AKI to CKD. MethodsMale BALB/c mice underwent bilateral renal pedicle clamping (AKI) or unilateral renal pedicle clamping with delayed contralateral nephrectomy (CKD) under isoflurane anaesthetic. Transdermal GFR monitoring and multi-spectral optoacoustic tomography in combination with statistical analysis were used to identify and standardise variables within these models. ResultsPre-clamping anaesthetic time was one of the most important predictors of AKI severity after R-IRI. Standardising pre-clamping time resulted in a more predictably severe AKI model. In the CKD model, initial improvement in renal function was followed by significant progressive reduction in function between weeks 2 and 4. Performing contralateral nephrectomy on day 14 enabled the development of CKD in a survivable way. ConclusionsNon-invasive monitoring of global and individual renal function after R-IRI is feasible, reproducible and correlates well with classical markers of injury. This facilitates refinement of kidney injury models and enables the degree of injury seen in pre-clinical models to be translated to those seen in the clinical setting. Thus, future therapies can be tested in a clinically relevant, non-invasive manner. What is already knownThe severity of Renal Ischaemia Reperfusion injury (R-IRI) varies between animal strain, gender and age. Experimental variables including temperature and clamping time are usually tightly controlled but significant variability still exists. Classically, small rodent experiments depend on endpoint evaluation of serum and histological features of disease. However, new technologies including transdermal glomerular filtration rate (GFR) monitoring and Multispectral Optoacoustic Tomography (MSOT) may enable renal function to be accurately monitored longitudinally, enabling better refinement of these models. What this study addsThis study shows that transdermal GFR measurements have reliably enabled refinement of the R-IRI model by standardisation of the duration of isoflurane prior to commencing surgery. Individual kidney function can be assessed in-vivo after unilateral R-IRI using MSOT imaging. The excretion tmax of IRDye-800 reliably represents the relative function of the injured kidney, permitting longitudinal in-vivo assessment of differential kidney function. What impact this may have on practiceThis study demonstrates the utility of two minimally-invasive in-vivo methods of monitoring kidney function which have advantages over classical methods and potentially enable fewer animals to be used in future studies. The study demonstrates refinement of bilateral and unilateral R-IRI models which will also enable a reduction in the number of animals needed for experimentation.

physiology↗

bioRxiv2017

Non-invasive imaging platform reveals a potential tumourigenicity hazard of systemically administered cells

BackgroundCell-based regenerative medicine therapies are now frequently tested in clinical trials. In many conditions, cell therapies are administered systemically, but there is little understanding of their fate, and adverse events are often under-reported. Currently, it is only possible to assess safety and fate of cell therapies in preclinical studies, specifically by monitoring animals longitudinally using multimodal imaging approaches. Here, using a suite of in vivo imaging modalities to explore the fate of a range of human and murine cells, we investigate how route of administration, cell type and host immune status affect the fate of administered cells.\n\nMethodsWe applied a unique imaging toolkit combining bioluminescence, optoacoustic and magnetic resonance imaging modalities to assess the safety of different human and murine cell types by following their biodistribution and persistence in mice following administration into the venous or arterial system. Results: Longitudinal imaging analyses (i) suggested that the intra-arterial route may be more hazardous than intravenous administration for certain cell types; (ii) revealed that the potential of a mouse mesenchymal stem/stromal cell (MSC) line to form tumours, depended on administration route and mouse strain; and (iii) indicated that clinically tested human umbilical cord (hUC)-derived MSCs can transiently and unexpectedly proliferate when administered intravenously to mice.\n\nConclusionsIn order to perform an adequate safety assessment of potential cell-based therapies, a thorough understanding of cell biodistribution and fate post administration is required. The non-invasive imaging toolbox used here can expose not only the general organ distribution of these therapies, but also a detailed view of their presence within different organs and, importantly, tumourigenic potential. Our observation that the hUC-MSCs but not the human bone marrow (hBM)-derived MSCs persisted for a period in some animals, suggests that therapies with these cells should proceed with caution.

cell biology↗