Biology subjects

Booth, C. J.

Publications and source records attributed to Booth, C. J..

7 recordsLinked to original sources

bioRxiv2025

CD8 T cells mediate immunosurveillance for neoantigen+ epithelial stem cells in the colon

Epithelial cells in the colon accumulate substantial numbers of somatic mutations, some of which can be recognised as neoantigens. The ability of CD8 T cells to survey for neoantigen+ cells in the healthy colon would provide an early detection mechanism to prevent cancer, but it is unclear whether neoantigen-specific CD8 T cells can mediate this process of immunosurveillance without becoming tolerant. To address this question, we used a genetically engineered mouse model to express a neoantigen in the epithelial cells of the adult proximal colon. Induction of neoantigen expression led to rapid elimination of neoantigen+ epithelial cells from the colon in a CD8 T cell-dependent manner. Neoantigen-specific CD8 T cells acquired cytolytic function within the colon tissue under steady-state conditions, which was required for elimination of the neoantigen+ epithelial cells. Despite the elimination of [~]25% of their epithelial cells over a two-day period, the colons looked histologically normal. Immunofluorescence and single-cell transcriptomic analyses revealed that neoantigen-specific CD8+ T cells specifically target neoantigen+ stem cells at the crypt base, which was associated with Ki67 in the crypt wall and abundance of neoantigen-negative stem cells. Infiltrating neoantigen-specific CD8 T cells made IFNg and expressed PD-1, raising the question of why PD-1-dependent suppression did not prevent the acquisition of effector functions by these neoantigen-specific CD8 T cells. Despite an increased signature of interferon-stimulated genes in colonic epithelial cells, PD-L1 expression was surprisingly absent. Moreover, we found that colonic epithelial stem cells also did not express PD-L1 under conditions of chronic inflammation, such as ulcerative colitis, immune checkpoint-induced colitis, and ageing, or when directly stimulated with IFN-{gamma} in vitro. Analyses of the PD-L1 gene promoter across humans and mice showed hypermethylation at sites associated with PD-L1 repression in cancer. Thus, our data support a model in which the acquisition of neoantigens by colonic epithelial cells triggers CD8 T cell-mediated immunosurveillance. This results in the elimination of PD-L1-negative neoantigen+ stem cells by effector CD8 T cells and simultaneous repair of the colon by neoantigen-negative epithelial cells to prevent immunopathology.

immunology↗

bioRxiv2025

Dysferlin Regulates Cardiac T-tubule Structure and Excitation-contraction Coupling in Isolated Cardiac Myocytes at Rest and in Response to Acute Hypo-osmotic Stress and is Protective Against Arrhythmias in Langendorff-perfused Hearts

Dysferlin is a membrane-associated protein that supports skeletal muscle function such that mutations in the DYSF gene can cause muscular dystrophy. Growing evidence suggests dysferlin regulates cardiac function, but this is less well understood. Tight regulation of the cardiac transverse-(T)-tubule network and excitation-contraction (EC) coupling mechanism is essential for healthy cardiac physiology. Remodelling of T-tubules and the EC coupling mechanism is observed during periods of cardiac stress and pathologies, promoting arrhythmias. However, little is known about how these processes are regulated and any protective mechanisms which may limit detrimental effects. Using a global dysferlin knockout (KO) mouse we have shown that the loss of dysferlin leads to a decrease in T-tubule density and the amplitude and rate of decay of the systolic Ca2+ transient but a narrowing of the dyadic cleft. Electrical mapping of ex vivo DYSF KO hearts shows they are more susceptible to ventricular arrhythmias. To induce stress, we used hypo-osmotic shock injury (OSI) to damage T-tubule networks in cardiac myocytes, in vitro. OSI increased T-tubule fragmentation and caused dysregulation of intracellular Ca2+ handling in dysferlin KO cells relative to WT controls. Finally, we observed that a natural decline in WT cardiac dysferlin abundance, which may contribute to the natural age-dependent maladaptive T-tubule remodelling that occurs in the mammalian ventricle. In summary, these findings demonstrate an essential role for dysferlin in cardiac physiology, especially during conditions of stress, which is decreased in normal ageing.

physiology↗

bioRxiv2025

Bioactive Enhanced Adjuvant Chemokine Oligonucleotide Nanoparticles (BEACONs) for Mucosal Vaccination Against Genital Herpes

Genital herpes, caused by herpes simplex virus-2 (HSV-2), remains a prevalent sexually transmitted infection with no available vaccine. Effective local immunity--including tissue-resident memory T cells (TRMs) and luminal antibodies--provides immediate viral control. Here, we developed Bioactive Enhanced Adjuvant Chemokine Oligonucleotide Nanoparticles (BEACON) formed via electrostatic interactions between CpG oligodeoxynucleotides (CpG ODN) and the chemokine CXCL9. This adjuvant enhances antigen-presenting cell engagement and innate immune signaling, promotes CD8+ T cell recruitment, and reduces local neutrophilic inflammation relative to CpG ODN. Co-administered vaginally with HSV-2 glycoproteins following intramuscular priming, BEACON improved protection against HSV-2 by increasing local CD8+ TRM populations and mucosal IgG and IgA responses. Vaccine-mediated protection required local delivery of both antigen and adjuvant, and was significantly reduced by CD8+ T cell or B cell depletion. These findings highlight the potential of engineered mucosal adjuvants for vaccines targeting genital herpes and other sexually transmitted infections. One-sentence summaryWe developed BEACON, a mucosal adjuvant that elicits protective immunity against genital herpes simplex virus 2 infection in mice.

immunology↗

bioRxiv2020

Type I Interferon Limits Viral Dissemination-Driven Clinical Heterogeneity in a Native Murine Betacoronavirus Model of COVID-19

Emerging clinical data demonstrates that COVID-19, the disease caused by SARS-CoV2, is a syndrome that variably affects nearly every organ system. Indeed, the clinical heterogeneity of COVID-19 ranges from relatively asymptomatic to severe disease with death resultant from multiple constellations of organ failures. In addition to genetics and host characteristics, it is likely that viral dissemination is a key determinant of disease manifestation. Given the complexity of disease expression, one major limitation in current animal models is the ability to capture this clinical heterogeneity due to technical limitations related to murinizing SARS-CoV2 or humanizing mice to render susceptible to infection. Here we describe a murine model of COVID-19 using respiratory infection with the native mouse betacoronavirus MHV-A59. We find that whereas high viral inoculums uniformly led to hypoxemic respiratory failure and death, lethal dose 50% (LD50) inoculums led to a recapitulation of most hallmark clinical features of COVID-19, including lymphocytopenias, heart and liver damage, and autonomic dysfunction. We find that extrapulmonary manifestations are due to viral metastasis and identify a critical role for type-I but not type-III interferons in preventing systemic viral dissemination. Early, but not late treatment with intrapulmonary type-I interferon, as well as convalescent serum, provided significant protection from lethality by limiting viral dissemination. We thus establish a Biosafety Level II model that may be a useful addition to the current pre-clinical animal models of COVID-19 for understanding disease pathogenesis and facilitating therapeutic development for human translation.

immunology↗

bioRxiv2020

Ketogenesis restrains aging-induced exacerbation of COVID in a mouse model

Increasing age is the strongest predictor of risk of COVID-19 severity. Unregulated cytokine storm together with impaired immunometabolic response leads to highest mortality in elderly infected with SARS-CoV-2. To investigate how aging compromises defense against COVID-19, we developed a model of natural murine beta coronavirus (mCoV) infection with mouse hepatitis virus strain MHV-A59 (mCoV-A59) that recapitulated majority of clinical hallmarks of COVID-19. Aged mCoV-A59-infected mice have increased mortality and higher systemic inflammation in the heart, adipose tissue and hypothalamus, including neutrophilia and loss of {gamma}{delta} T cells in lungs. Ketogenic diet increases beta-hydroxybutyrate, expands tissue protective {gamma}{delta} T cells, deactivates the inflammasome and decreases pathogenic monocytes in lungs of infected aged mice. These data underscore the value of mCoV-A59 model to test mechanism and establishes harnessing of the ketogenic immunometabolic checkpoint as a potential treatment against COVID-19 in the elderly. Highlights - Natural MHV-A59 mouse coronavirus infection mimics COVID-19 in elderly. - Aged infected mice have systemic inflammation and inflammasome activation - Murine beta coronavirus (mCoV) infection results in loss of pulmonary {gamma}{delta} T cells. - Ketones protect aged mice from infection by reducing inflammation. eTOC BlurbElderly have the greatest risk of death from COVID-19. Here, Ryu et al report an aging mouse model of coronavirus infection that recapitulates clinical hallmarks of COVID-19 seen in elderly. The increased severity of infection in aged animals involved increased inflammasome activation and loss of {gamma}{delta} T cells that was corrected by ketogenic diet.

immunology↗

bioRxiv2020

CECR2 Drives Breast Cancer Metastasis by Suppressing Macrophage Inflammatory Responses

Epigenetic and transcriptional changes are critical for metastasis, the major cause of cancer-related deaths. Metastatic tumor cells escape immune surveillance more efficiently than tumor cells in the primary sites, but the mechanisms controlling their immune evasion are poorly understood. We found that distal metastases are more immune inert with increased M2 macrophages compared to their matched primary tumors. Acetyl-lysine reader CECR2 is an epigenetic regulator upregulated in metastases and positively associated with M2 macrophages. CECR2 specifically promotes breast cancer metastasis in multiple mouse models, with more profound effect in the immunocompetent setting. Mechanistically, NF-{kappa}B family member RELA recruits CECR2 to activate CSF1 and CXCL1, which are critical for macrophage-mediated immunosuppression at the metastatic sites. Furthermore, pharmacological inhibition of CECR2 bromodomain impedes NF-{kappa}B-mediated immune suppression by macrophages and inhibits breast cancer metastasis. These results reveal novel therapeutic strategies to treat metastatic breast cancer. Statement of SignificanceComparison of matched primary breast tumors and distal metastases show that metastases are more immune inert with increased tumor promoting macrophages. Depletion or pharmacological inhibition of CECR2 inhibits breast cancer metastasis by suppressing macrophage inflammatory responses, nominating CECR2 as a promising therapeutic target for cancer metastasis.

cancer biology↗

bioRxiv2019

High-phytate/low-calcium diet is a risk factor for crystal nephropathies, renal phosphate wasting, and bone loss

Phosphate overload contributes to mineral bone disorders associated with crystal nephropathies. Phytate, the major form of phosphorus in plant seeds, is known as an indigestible and negligible in humans. However, the mechanism and adverse effects of high-phytate intake on Ca2+ and phosphate absorption and homeostasis are unknown. Here we show that excessive intake of phytate with a low-Ca2+ diet fed to rats contributed to the development of crystal nephropathies, renal phosphate wasting, and bone loss through tubular dysfunction secondary to dysregulation of intestinal calcium and phosphate absorption. Moreover, Ca2+ supplementation alleviated the detrimental effects of excess dietary phytate on bone and kidney through excretion of undigested Ca2+-phytate, which prevented a vicious cycle of intestinal phosphate overload and renal phosphate wasting while improving intestinal Ca2+ bioavailability. Thus, we demonstrate that phytate is digestible without a high-Ca2+ diet and a risk factor for phosphate overloading and developing crystal nephropathies and bone disease.

physiology↗