Project description:Myxomas, the most common primary tumor of the heart, usually develop in the atria and consist of a myxoid matrix composed of an acid-mucopolysaccharide-rich stroma with polygonal stromal cells scattered throughout the matrix. These benign tumors, despite their rarity, are a research focus because of their clinical presentation and uncertain histogenesis. The objective of this study was to assess whether adult cardiac stem/progenitor cells (CSCs) give rise to myxoma stromal cells and secrete the typical myxoid matrix. 23 collected tumors showed the typical histological features of cardiac atrial myxoma with polygonal cells positive for the myxoma tumor-cell marker, calretinin, dispersed in an abundant myxoid matrix. We detected myxoma cells positive for c-kit (c-kitpos) but very rare Isl-1 positive cells. Most of these c-kitpos cells were lineage-committed CD45pos/CD31pos cells. However, c-kitpos /CD45neg/CD31neg cardiac myxoma cells expressed stemness and cardiac progenitor cell transcription factors. Some (<10%) of these c-kitpos/ CD45neg/CD31neg/ myxoma cells expressed also calretinin, representing myxoma stromal precursor cells. c-kitpos/CD45neg/CD31neg cardiac myxoma cells secrete in vitro chondroitin-6-sulfate and hyaluronic acid, composing the gelatinous matrix of cardiac myxoma in vivo. In vitro, c-kitpos/CD45neg/CD31neg myxoma cells have stem cell properties being clonogenic, self-renewing and sphere forming. On the other hand, they exhibited an abortive cardiac differentiation potential with significant changes in their mRNA and microRNA transcriptome compared to normal c-kitpos/CD45neg /CD31neg CSCs. Importantly, myxoma-derived CSCs seed human atrial myxoma in xenograft’s experiments in NOD/SCID mice. Thus, un-committed c-kitpos/CD45neg /CD31neg cells fulfill the criteria of myxoma stem cells in atrial myxoma. Myxomas appear to be the first CSC-related human cardiac disease.
Project description:Myxomas, the most common primary tumor of the heart, usually develop in the atria and consist of a myxoid matrix composed of an acid-mucopolysaccharide-rich stroma with polygonal stromal cells scattered throughout the matrix. These benign tumors, despite their rarity, are a research focus because of their clinical presentation and uncertain histogenesis. The objective of this study was to assess whether adult cardiac stem/progenitor cells (CSCs) give rise to myxoma stromal cells and secrete the typical myxoid matrix. 23 collected tumors showed the typical histological features of cardiac atrial myxoma with polygonal cells positive for the myxoma tumor-cell marker, calretinin, dispersed in an abundant myxoid matrix. We detected myxoma cells positive for c-kit (c-kitpos) but very rare Isl-1 positive cells. Most of these c-kitpos cells were lineage-committed CD45pos/CD31pos cells. However, c-kitpos /CD45neg/CD31neg cardiac myxoma cells expressed stemness and cardiac progenitor cell transcription factors. Some (<10%) of these c-kitpos/ CD45neg/CD31neg/ myxoma cells expressed also calretinin, representing myxoma stromal precursor cells. c-kitpos/CD45neg/CD31neg cardiac myxoma cells secrete in vitro chondroitin-6-sulfate and hyaluronic acid, composing the gelatinous matrix of cardiac myxoma in vivo. In vitro, c-kitpos/CD45neg/CD31neg myxoma cells have stem cell properties being clonogenic, self-renewing and sphere forming. On the other hand, they exhibited an abortive cardiac differentiation potential with significant changes in their mRNA and microRNA transcriptome compared to normal c-kitpos/CD45neg /CD31neg CSCs. Importantly, myxoma-derived CSCs seed human atrial myxoma in xenograft’s experiments in NOD/SCID mice. Thus, un-committed c-kitpos/CD45neg /CD31neg cells fulfill the criteria of myxoma stem cells in atrial myxoma. Myxomas appear to be the first CSC-related human cardiac disease.
Project description:Cardiac myxoma is a commonly encountered, potentially life-threatening tumor within the heart. We used single-cell RNA sequencing (scRNA-seq) to analyze the identification and characterization of cellular subtypes, cell trajectory analysis, and intercellular communication of cardiac myxoma tissues.
Project description:Background : Poxviruses have been shown to be efficient vectors for the production of protective immune responses in host species but also in on host species. Myxoma virus belongs to poxviridae family. In order to evaluate the capacity of (MYXV) as a vaccine vector in ruminants, we invistigated its interactions with bone marrow-derived dendritic cells (BM-DC). DCs are the most potent antigen-presenting cells and play a crucial role during the priming and reactivation of antigen-specific immune responses . Following infection by a pathogen, the functional changes of DC are essential since priming and polarization of the immune response depend on these changes . Therefore a better understanding of the modifications in gene expression of proinflammatory cytokines, chemokines and stimulatory molecules expression may prove useful in predicting whether or not a vaccine vector will be effective. Moreover, it may help identifying modifications for improving its efficacy. Methodology/Principal Findings: We investigated in vitro the interactions between recombinant MYXV expressing GFP protein, SG33-GFP and ovine BM-DCs. To gain a global view of the gene remodelling induced by MYXV, we infected BM-DCs from three sheep with SG33-GFP at different multiplicity of infection (MOI) (0, 1, 3) during different time (0, 3, 8 hours). We measured the expression of 15K probes in BM-DCs after each kind of conditions with ovine Agilent microarrays. Furthermore, a selected number of genes were confirmed by RT-qPCR. MYXV infection induces a strong reprogramming of the cells leading to the expression of pro-inflammatory cytokines and mobilisation of type I IFN pathways, cellular death and features associated with the activation of the adaptive immune response. Conclusion/Significance: Microarray profiling of a poxvirus-DC interaction help to delineate some interesting features of a vector candidate in ovine, and pave the way for additional improvements of a promising platform. Keywords : Myxoma virus ; bone marrow-derived dendritic cells ; transcriptome ; sheep; vaccine 9 samples: 3 time points and 3 replicates of MOI=1
Project description:Modelling combined virotherapy and immunotherapy:strengthening the antitumour immune response mediated byIL-12 and GM-CSF expression
Adrianne L. Jennera, Chae-Ok Yunb, Arum Yoonb, Adelle C. F. Costercand Peter S. Kimaa
School of Mathematics and Statistics, University of Sydney, Sydney, Australia;bDepartment ofBioengineering, Hanyang University, Seoul, Korea;cSchool of Mathematics and Statistics, University of NewSouth Wales, Sydney, Australia
ABSTRACT
Combined virotherapy and immunotherapy has been emergingas a promising and effective cancer treatment for some time.Intratumoural injections of an oncolytic virus instigate an immunereaction in the host, resulting in an influx of immune cells tothe tumour site. Through combining an oncolytic viral vector withimmunostimulatory cytokines an additional antitumour immuneresponse can be initiated, whereby immune cells induce apoptosisin both uninfected and virus infected tumour cells. We developa mathematical model to reproduce the experimental results fortumour growth under treatment with an oncolytic adenovirus co-expressing the immunostimulatory cytokines interleukin 12 (IL-12)and granulocyte-monocyte colony stimulating factor (GM-CSF). Byexploring heterogeneity in the immune cell stimulation by thetreatment, we find a subset of the parameter space for the immunecell induced apoptosis rate, in which the treatment will be lesseffective in a short time period. Therefore, we believe the bivariatenature of treatment outcome, whereby tumours are either completelyeradicated or grow unbounded, can be explained by heterogeneity inthis immune characteristic. Furthermore, the model highlights theapparent presence of negative feedback in the helper T cell and APCstimulation dynamics, when IL-12 and GM-CSF are co-expressed asopposed to individually expressed by the viral vector.