iNOS expressing macrophages co-localize with nitrotyrosine staining after myocardial infarction in humans

IntroductionInducible nitric oxide synthase (iNOS) produces micromolar amounts of nitric oxide (NO) upon the right stimuli, whose further reactions can lead to oxidative stress. In murine models of myocardial infarction (MI), iNOS is known to be expressed in infiltrating macrophages, which at early onset enter the infarcted zone and are associated with inflammation. In contrast cardiac tissue resident macrophages are thought to enhance regeneration of tissue injury and re-establish homeostasis. Both detrimental and beneficial effects of iNOS have been described, still the role of iNOS in MI is not fully understood. Our aim was to examine cell expression patterns of iNOS and nitrotyrosine (NT) production in human MI.Material and MethodsWe examined in postmortem human MI hearts the iNOS mRNA expression by means of qPCR. Further we performed immunohistochemical stainings for cell type identification. Afterwards a distance analysis between iNOS and NT was carried out to determine causality between iNOS and NT production.ResultsiNOS mRNA expression was significantly increased in infarcted regions of human MI hearts and iNOS protein expression was detected in resident macrophages in infarcted human hearts as well as in controls hearts, being higher in resident macrophages in MI hearts compared to control. Furthermore in MI and in healthy human hearts cells showing signs of NT production peaked within 10–15 µm proximity of iNOS+ cells.DiscussionThese results indicate that, unexpectedly, resident macrophages are the main source of iNOS expression in postmortem human MI hearts. The peak of NT positive cells within 10–15 µm of iNOS+ cells suggest an iNOS dependent level of NT and therefore iNOS dependent oxidative stress. Our results contribute to understanding the role of iNOS in human MI

Response to primary chemoradiotherapy of locally advanced oropharyngeal carcinoma is determined by the degree of cytotoxic T cell infiltration within tumor cell aggregates

BackgroundEffective anti-tumor immune responses are mediated by T cells and require organized, spatially coordinated interactions within the tumor microenvironment (TME). Understanding coordinated T-cell-behavior and deciphering mechanisms of radiotherapy resistance mediated by tumor stem cells will advance risk stratification of oropharyngeal cancer (OPSCC) patients treated with primary chemoradiotherapy (RCTx).MethodsTo determine the role of CD8 T cells (CTL) and tumor stem cells for response to RCTx, we employed multiplex immunofluorescence stains on pre-treatment biopsy specimens from 86 advanced OPSCC patients and correlated these quantitative data with clinical parameters. Multiplex stains were analyzed at the single-cell level using QuPath and spatial coordination of immune cells within the TME was explored using the R-package Spatstat.ResultsOur observations demonstrate that a strong CTL-infiltration into the epithelial tumor compartment (HR for overall survival, OS: 0.35; p<0.001) and the expression of PD-L1 on CTL (HR: 0.36; p<0.001) were both associated with a significantly better response and survival upon RCTx. As expected, p16 expression was a strong predictor of improved OS (HR: 0.38; p=0.002) and correlated with overall CTL infiltration (r: 0.358, p<0.001). By contrast, tumor cell proliferative activity, expression of the tumor stem cell marker CD271 and overall CTL infiltration, regardless of the affected compartment, were not associated with response or survival.ConclusionIn this study, we could demonstrate the clinical relevance of the spatial organization and the phenotype of CD8 T cells within the TME. In particular, we found that the infiltration of CD8 T cells specifically into the tumor cell compartment was an independent predictive marker for response to chemoradiotherapy, which was strongly associated with p16 expression. Meanwhile, tumor cell proliferation and the expression of stem cell markers showed no independent prognostic effect for patients with primary RCTx and thus requires further study

Functions of extracellular vesicle mediated signaling from blood to brain in neurodegenerative diseases

Cellular communication is a concept that can be explained as the transfer of signals or material (such as cytokines, ions, small molecules) between cells from the same or different type, across either short or long distances. Once this signal or material is received, it will, as a rule, promote a functional effect. Several routes, involved in this transfer, are well described and are of global importance for organ/tissue communication in an organism. The brain interacts dynamically with the immune system, and the main route known to mediate this communication, is via the release of cytokines (by peripheral blood cells), which can then activate certain brain cell types, such as microglia, directly, or activate the vagus nerve transferring signals to neuronal populations in the brain. The communication between these two systems plays a key role in the pathophysiology of neurodegenerative diseases, and the mechanisms involved in this interaction are of central importance for understanding disease initiation and progression and search for therapeutic models. The Momma lab previously addressed the mechanisms of interaction between the peripheral immune system and the brain by investigating cellular fusion of haematopoietic cells with neurons after inflammation. They addressed the question of whether this phenomenon also occurs under non-invasive conditions. To approach this problem, a genetic tracing model that relies on the Cre-Lox recombination system was used. Transgenic mice expressing Cre recombinase specifically in the haematopoietic lineage were crossed into a Cre-reporter background, thus all haematopoietic cells irreversibly express the reporter marker-gene EYFP. Using this model, EYFP was detected in non-haematopoietic tissues, suggesting the existence of a communication mechanism never described before. As cells containing two nuclei were never detected, fusion as a mechanism was excluded, suggesting that Cre reaches non-haematopoietic cells via a different signalling pathway. The Momma lab investigated whether the transfer of material through extracellular vesicles (EVs) could be behind this periphery-to-brain communication. Using the genetic mouse model, they were able to trace the transfer of Cre RNA via EVs between cells in vivo, generating the first in vivo evidence of functional RNA transfer by EVs between blood and brain. The last decade has witnessed a rapid expansion of the field of EVs. Initially considered as waste disposal material, recent evidence has challenged this view. EVs are currently considered as a widespread intercellular communication system that can transport and transfer all types of biomolecules, from nucleic acids to lipids and proteins. However, several important questions are still under investigation. One of them is whether EVs are involved in brain pathophysiology, as inflammation plays an important role in onset and progression of neurodegenerative diseases and is well described in Parkinson Disease (PD). Based on preliminary data in a mouse, peripherally injected with a low dose of Lipopolysaccharide (LPS, an endotoxin found in the outer-membrane of Gram-negative bacteria, which causes an immune response), neurons and other cell population in the brain take up EVs from the periphery. Particularly, dopaminergic neurons from Substantia Nigra and Ventral Tegmental Area have been shown to receive functional RNA, transported through EVs, which can lead up to 20% of recombination. Furthermore, different neuronal populations from Hippocampus, Cortex and Cerebellum exhibit recombination, indicating a widespread signalling from blood to the brain. Therefore, the goal of my PhD thesis was to investigate the mechanisms of this transfer and the triggers that lead to EV uptake by neural cells in vivo both in pathological and physiological conditions. In this project, the extent and function of EV-mediated signalling from blood to brain is explored in the context of peripheral inflammation and neurodegenerative diseases. Firstly, EVs isolated from WT mice were further characterized using size-exclusion chromatography (SEC), Western Blot (WB) and electron microscopy in order to extend the knowledge from previous work done in the Momma lab. Secondly, to expand on the biological relevance of the fact that inflammation is correlated with an increase in EV uptake, different approaches using the genetic murine tracing model were used. Recombination events from haematopoietic cells to the brain have been followed after peripheral injection of LPS. Peripheral inflammation caused by LPS injection led to widespread recombination events in the brain, specifically in microglia and neurons, including dopaminergic (DA) neurons. In contrast, astrocytes, oligodendrocytes and endothelial cells were never or very rarely recombined. Additionally, peripheral LPS injection in a murine model, where Cre is expressed only in erythrocytes, led to recombination events only in microglia, suggesting that the type of EV-secreting cell plays a role in the targeting of EVs to a specific cell population

Neuronal activity triggers uptake of hematopoietic extracellular vesicles in vivo

Communication with the hematopoietic system is a vital component of regulating brain function in health and disease. Traditionally, the major routes considered for this neuroimmune communication are by individual molecules such as cytokines carried by blood, by neural transmission, or, in more severe pathologies, by the entry of peripheral immune cells into the brain. In addition, functional mRNA from peripheral blood can be directly transferred to neurons via extracellular vesicles (EVs), but the parameters that determine their uptake are unknown. Using varied animal models that stimulate neuronal activity by peripheral inflammation, optogenetics, and selective proteasome inhibition of dopaminergic (DA) neurons, we show that the transfer of EVs from blood is triggered by neuronal activity in vivo. Importantly, this transfer occurs not only in pathological stimulation but also by neuronal activation caused by the physiological stimulus of novel object placement. This discovery suggests a continuous role of EVs under pathological conditions as well as during routine cognitive tasks in the healthy brain

Neuronal activity triggers uptake of hematopoietic extracellular vesicles in vivo

Communication with the hematopoietic system is a vital component of regulating brain function in health and disease. Traditionally, the major routes considered for this neuroimmune communication are by individual molecules such as cytokines carried by blood, by neural transmission, or, in more severe pathologies, by the entry of peripheral immune cells into the brain. In addition, functional mRNA from peripheral blood can be directly transferred to neurons via extracellular vesicles (EVs), but the parameters that determine their uptake are unknown. Using varied animal models that stimulate neuronal activity by peripheral inflammation, optogenetics, and selective proteasome inhibition of dopaminergic (DA) neurons, we show that the transfer of EVs from blood is triggered by neuronal activity in vivo. Importantly, this transfer occurs not only in pathological stimulation but also by neuronal activation caused by the physiological stimulus of novel object placement. This discovery suggests a continuous role of EVs under pathological conditions as well as during routine cognitive tasks in the healthy brain

Red blood cell-derived extracellular vesicles mediate intercellular communication in ischemic heart failure

Summary Extracellular vesicles (EV) mediate intercellular signaling by transferring their cargo to recipient cells. Red blood cell (RBC)-derived EVs constitute a significant proportion of circulating EVs and have been implicated in regulating immune responses. Here, we describe a transgenic mouse model for fluorescent-based mapping of RBC-EV target cells based on the functional transfer of EV-contained Cre-recombinase to target cells. In a murine model of ischemic heart failure, we detect an increase in RBC-EV-targeted cardiomyocytes in the hearts and microglial cells in the brains. Cells targeted by RBC-EVs present an enrichment of genes implicated in cell proliferation and metabolism pathways compared to non-recombined (non-targeted) cells. Cardiomyocytes targeted by RBC-EVs are more likely to demonstrate cellular markers of DNA synthesis and proliferation, suggesting functional significance of EV-mediated signaling. In conclusion, we leverage our mouse model for mapping of RBC-EV targets in murine ischemic heart failure to demonstrate quantitative and qualitative changes in RBC-EV recipients

Neoadjuvant chemoradiotherapy for oral cavity cancer: predictive factors for response and interim analysis of the prospective INVERT-Trial

Background: To study neoadjuvant chemoradiotherapy (nCRT) and potential predictive factors for response in locally advanced oral cavity cancer (LA-OCC). Methods: The INVERT trial is an ongoing single-center, prospective phase 2, proof-of-principle trial. Operable patients with stage III-IVA squamous cell carcinomas of the oral cavity were eligible and received nCRT consisting of 60 Gy with concomitant cisplatin and 5-fluorouracil. Surgery was scheduled 6-8 weeks after completion of nCRT. Explorative, multiplex immunohistochemistry (IHC) was performed on pretreatment tumor specimen, and diffusion-weighted magnetic resonance imaging (DW-MRI) was conducted prior to, during nCRT (day 15), and before surgery to identify potential predictive biomarkers and imaging features. Primary endpoint was the pathological complete response (pCR) rate. Results: Seventeen patients with stage IVA OCC were included in this interim analysis. All patients completed nCRT. One patient died from pneumonia 10 weeks after nCRT before surgery. Complete tumor resection (R0) was achieved in 16/17 patients, of whom 7 (41%, 95% CI: 18-67%) showed pCR. According to the Clavien-Dindo classification, grade 3a and 3b complications were found in 4 (25%) and 5 (31%) patients, respectively; grade 4-5 complications did not occur. Increased changes in the apparent diffusion coefficient signal intensities between MRI at day 15 of nCRT and before surgery were associated with better response (p=0.022). Higher abundances of programmed cell death protein 1 (PD1) positive cytotoxic T-cells (p=0.012), PD1+ macrophages (p=0.046), and cancer-associated fibroblasts (CAFs, p=0.036) were associated with incomplete response to nCRT. Conclusion: nCRT for LA-OCC followed by radical surgery is feasible and shows high response rates. Larger patient cohorts from randomized trials are needed to further investigate nCRT and predictive biomarkers such as changes in DW-MRI signal intensities, tumor infiltrating immune cells, and CAFs

SnRNA sequencing defines signaling by RBC-derived extracellular vesicles in the murine heart.

Extracellular vesicles (EVs) mediate intercellular signaling by transferring their cargo to recipient cells, but the functional consequences of signaling are not fully appreciated. RBC-derived EVs are abundant in circulation and have been implicated in regulating immune responses. Here, we use a transgenic mouse model for fluorescence-based mapping of RBC-EV recipient cells to assess the role of this intercellular signaling mechanism in heart disease. Using fluorescent-based mapping, we detected an increase in RBC-EV-targeted cardiomyocytes in a murine model of ischemic heart failure. Single cell nuclear RNA sequencing of the heart revealed a complex landscape of cardiac cells targeted by RBC-EVs, with enrichment of genes implicated in cell proliferation and stress signaling pathways compared with non-targeted cells. Correspondingly, cardiomyocytes targeted by RBC-EVs more frequently express cellular markers of DNA synthesis, suggesting the functional significance of EV-mediated signaling. In conclusion, our mouse model for mapping of EV-recipient cells reveals a complex cellular network of RBC-EV-mediated intercellular communication in ischemic heart failure and suggests a functional role for this mode of intercellular signaling

Supplementary Figures 1-12 from Colorectal Cancer Organoid–Stroma Biobank Allows Subtype-Specific Assessment of Individualized Therapy Responses

Supplementary Figure S1 shows light microscopic images of CRC organoids and CAFs. Supplementary Figure S2 shows immunostaining and RNA sequencing analysis of cultured CAFs. Supplementary Figure S3 shows chromosomal copy number changes in tumors and matched organoids. Supplementary Figure S4 shows the transcriptional variation among tumors and organoids. Supplementary Figure S5 shows the classification of cancer intrinsic subtypes (CRIS) in tumors, matched organoids and xenotransplants. Supplementary Figure S6 shows the tissue microarray analysis of the of tumor samples from the colorectal cancer organoid-stroma biobank cohort. Supplementary Figure S7 shows the association of growth characteristics with molecular features of colorectal cancer organoid-stroma biobank. Supplementary Figure S8 shows the shows CMS and CRIS classifications of tumors and of matched organoids in different contexts. Supplementary Figure S9 describes the establishment of a drug screening workflow in 3D organoid-stroma co-cultures. Supplementary Figure S10 describes the development of a dual luciferase assay to study cell viability simultaneously in organoids and CAFs. Supplementary Figure S11 demonstrates that the MET inhibitor BAY-474 sensitizes Gefitinib resistant co-cultures. Supplementary Figure S12 shows the association of identified sensitivity and resistance signatures with gene expression and prognosis in different CMS.</p