Tumor innate immunity primed by specific interferon-stimulated endogenous retroviruses.

Mesenchymal tumor subpopulations secrete pro-tumorigenic cytokines and promote treatment resistance1-4. This phenomenon has been implicated in chemorefractory small cell lung cancer and resistance to targeted therapies5-8, but remains incompletely defined. Here, we identify a subclass of endogenous retroviruses (ERVs) that engages innate immune signaling in these cells. Stimulated 3 prime antisense retroviral coding sequences (SPARCS) are oriented inversely in 3' untranslated regions of specific genes enriched for regulation by STAT1 and EZH2. Derepression of these loci results in double-stranded RNA generation following IFN-γ exposure due to bi-directional transcription from the STAT1-activated gene promoter and the 5' long terminal repeat of the antisense ERV. Engagement of MAVS and STING activates downstream TBK1, IRF3, and STAT1 signaling, sustaining a positive feedback loop. SPARCS induction in human tumors is tightly associated with major histocompatibility complex class 1 expression, mesenchymal markers, and downregulation of chromatin modifying enzymes, including EZH2. Analysis of cell lines with high inducible SPARCS expression reveals strong association with an AXL/MET-positive mesenchymal cell state. While SPARCS-high tumors are immune infiltrated, they also exhibit multiple features of an immune-suppressed microenviroment. Together, these data unveil a subclass of ERVs whose derepression triggers pathologic innate immune signaling in cancer, with important implications for cancer immunotherapy

Structure-function properties of the gastrodigestive and hepatic systems of zebrafish (Danio rerio)

While they lack mammal-specific organs, zebrafish provide a high degree of resemblance in their genetic profile, molecular mechanisms and organ physiology to humans and have been established as an excellent complementary platform to rodents. However, their use in gastroenterology and hepatology is under-utilised, conceivably due to a lack of digestive system ultrastructural details as most anatomical studies were performed by light and fluorescence imaging. This thesis provides detailed insights into the structure and function of the zebrafish digestive system, particularly the liver. Multimodal bio-imaging approaches were developed in order to investigate the hepatic ultrastructure and function. Using a protocol that renders samples compatible with multiple imaging platforms, we produce a detailed map of the zebrafish gastrodigestive system from organ to subcellular levels. Findings were compared with the rodent/human counterparts and while some differences exist between the zebrafish and the rodent/human hepatic parenchymal cells and biliary system organisations, many similarities, at the sub/cellular levels, were also demonstrated. Using advances in genetics and a protocol that retains endogenous fluorescence within zebrafish at the same time as ultrastructure for electron microscopy, we further investigated key hepatic functional properties (e.g. macromolecular transport routes) by performing albumin injections and studying the liver macrophages. While we demonstrated similarities in the albumin uptake pathway and in the morphology of liver macrophages in zebrafish, we reveal that zebrafish liver macrophages lack of phagocytic function (a key aspect in rodents and human), which may limit their use in hepatic-immune diseases studies. Altogether, our studies provide new insights and novel protocols for the analysis of the zebrafish liver and lay a foundation to further evaluate uptake routes for gastro-digestive research and drug delivery in various diseases

Spectral imaging in preclinical research and clinical pathology.

Spectral imaging methods are attracting increased interest from researchers and practitioners in basic science, pre-clinical and clinical arenas. A combination of better labeling reagents and better optics creates opportunities to detect and measure multiple parameters at the molecular and cellular level. These tools can provide valuable insights into the basic mechanisms of life, and yield diagnostic and prognostic information for clinical applications. There are many multispectral technologies available, each with its own advantages and limitations. This chapter will present an overview of the rationale for spectral imaging, and discuss the hardware, software and sample labeling strategies that can optimize its usefulness in clinical settings

Diffusion-weighted Imaging of Lymph Node Tissue

Purpose: The study investigates the hypothesis of clinically observed decreased apparent diffusion coefficient (ADC) of cancerous lymph nodes can be attributed to increased cellularity. The study characterises the mean diffusivity (MD) of lymph node sub-structures and investigates correlation between MD and cellularity metrics. The study also investigates the theoretical information content of single and multi-biophysical models. Methods:. A 3 mm diameter core sample was extracted from a formalin fixed lymph node tissue post-surgery and imaged using 9.4T and 16.4T Bruker MRI system. Samples were sectioned and stained with haematoxylin and eosin (H&E). Diffusion tensor model was fitted voxelwise and MD values were computed using Matlab. Cellularity metrics includes measurement of nuclear count and nuclear area. Eleven models with combinations of isotropic, anisotropic, and restricted components were tested for diffusion modelling and ranked using the Akaike information criterion (AIC). Results: The findings showed distinct diffusivities of lymph node sub-structures (capsule and parenchyma). Parenchyma in normal lymph node tissues had higher MD (0.71 ± 0.17 µm2/ms) than metastatic parenchyma (0.52 ± 0.08 µm2/ms) and lymphoma (0.47 ± 0.19 µm2/ms). No correlation were observed between MD and nuclear count (r = 0.368) and nuclear area (r = 0.368) respectively at 95 % confidence intervals. The single biophysical models (ADC and DTI) were ranked lowest by AIC. Multi-biophysical models consist of anisotropic and restricted diffusion (Zeppelin-sphere, Ball-stick-sphere, and Ball-sphere) were ranked highest in the majority of voxels of the tissue samples. Conclusion: A distinct diffusivity value were found in lymph node sub-structures with no correlation to cellularity. Multi-biophysical models were ranked highest and extract more information from the measurement data than simple single biophysical models