IMMU-18. GLIOBLASTOMA-DERIVED EXTRACELLULAR VESICLES INDUCE DRAMATIC CHANGES IN THE TRANSCRIPTOMIC LANDSCAPE OF MONOCYTES

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi95-vi95
Author(s):  
Benjamin Himes ◽  
Cody Nesvick ◽  
Helen Li ◽  
Mi-Yeon Jung ◽  
Ian Parney

Abstract Glioblastoma (GBM) is the most common and deadly primary brain tumor. Novel therapeutic strategies are urgently needed to improve outcomes, but a number of disease-specific barriers pose challenges to innovation. Tumor-mediated immunosuppression is one such hurdle, and a growing body of evidence suggests that GBM-derived extracellular vesicles (EVs) play an important role in host immunosuppression. GBM-derived EVs have been shown to induce the formation of immunosuppressive monocytes, including myeloid-derived suppressor cells. Work by our group and others has increasingly shown that these immunosuppressive monocytes are a heterogenous group, and that many constellations of surface markers are inadequate to capture the changes wrought by EVs. In order to better understand the effects of GBM-EVs on monocytes, we conducted RNA-seq analysis on monocytes collected from four healthy donors treated with GBM-derived EVs harvested by ultracentrifugation from the patient-derived BT116 cell line. Following 72h of EV conditioning, total RNA was harvested from treated monocytes and untreated controls. RNA-seq was performed using the Illumina HiSeq4000 platform with paired end index reads. Analysis was performed using RNA STAR and the hg19 ENCODE reference sequence. Differential expression analysis was performed using DESeq2. Genes with a false-discovery rate (FDR)-corrected P value < 0.05 and a log2 fold-change value of >|1| were considered significantly different between groups. Pathway analysis was performed using ClueGO in Cytoscape (GO term fusion on, p< 0.05). Unsupervised clustering analysis of the top 500 most differentially-expressed genes demonstrated grouping of BT116 EV-treated monocytes together versus untreated monocytes. Pathway analysis upregulated genes in pathways important for heparan sulfate proteoglycan synthesis and cholesterol synthesis, which could potentially point to positive regulation of EV uptake. Downregulated pathways included regulation of T cell differentiation and chemoattractant activity, underscoring the induction of a potentially immunosuppressive phenotype by GBM-derived EVs.

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi126-vi127
Author(s):  
Benjamin Himes ◽  
Timothy Peterson ◽  
Jasmine Tyson ◽  
Helen Lee ◽  
Tristan deMooij ◽  
...  

Abstract Glioblastoma (GBM) is the most common and lethal primary brain tumor, and novel therapeutic strategies that make a substantial impact on outcomes are sorely needed. Immunotherapies have shown great promise in the treatment of a number of cancers in recent year, and a concerted effort is being made to apply these treatment paradigms to GBM. However, many GBM patients exhibit profound immunosuppression, likely limiting the efficacy of such approaches. The mechanisms of this immunosuppression are poorly understood, but tumor-derived extracellular vesicles (EVs), may play a role. We demonstrate that GBM-derived EVs induce the development of myeloid-derived suppressor cells (MDSCs) and non-classical monocytes (NCMs). We further demonstrate that these EV-induced monocytic cells are immunosuppressive, resulting in impaired T cell proliferation upon co-culture. We found that the immunosuppressive effects of tumor-derived EVs appear to be driven by the induction of these immunosuppressive monocytes, as EV treatment of T cells did not significantly impact T cell proliferation. Further, we sought to characterize the important of programmed death ligand 1 (PD-L1) in the induction of these immunosuppressive monocyte populations. We found PD-L1 to be expressed in the EVs from GBM cell lines, and that modulation in PD-L1 expression via either constitutive overexpression or shRNA-mediated knockdown resulted in concordant changes in expression in tumor-derived EVs. We demonstrate that PD-L1 is important for the induction of NCM but not for MDSCs. Taken together, these findings point to a significant role for tumor-derived EVs in the induction of immunosuppressive monocytes in GBM, and that these cells may be a driving force of systemic immunosuppression. PD-L1 is one factor expressed in EVs that has immunomodulatory properties, but additional EV cargo likely plays a major role in the induction of immunosuppressive cells.


2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Dionysios V Chartoumpekis ◽  
Panos Ziros ◽  
Ioannis Habeos ◽  
Venetsana Kyriazopoulou ◽  
Adam Smith ◽  
...  

Abstract Nrf2 (Nfe2l2) is a transcription factor that regulates a series of cytoprotective and antioxidant enzymes. Its cytoplasmic inhibitor Keap1 senses the presence of oxidative or electrophilic stress though the interaction of sulfhydryl groups of its cysteines with reactive species and ceases to bind Nrf2. Thus, Nrf2 can transfer to the nucleus and induce its target genes. Follicular thyroid cells have physiologically high levels of reactive oxygen species as oxidation of iodine is essential for iodination of thyroglobulin and thyroid hormones synthesis. We have shown previously that Nrf2 pathway is active in thyroid and regulates the transcription of thyroglobulin. We thus hypothesized that the response of thyroid to iodine excess should comprise Nrf2-dependent and -independent pathways. To this end, 3 months-old male C57Bl6J WT or Nrf2 knockout (KO) mice were exposed to 0.05% sodium iodide in their water for 7 days. Thyroids were excised and used for RNA extraction; RNA-seq was performed by Exiqon, with a fold-change cutoff set at 2. Selected representative genes of the enriched pathways were quantified by real-time qPCR to validate RNA-seq results. Pathway analysis of the differentially expressed genes was performed using the Ingenuity Pathway Analysis (IPA) software. Pathways that were enriched with a p-value<0.05 were considered significant. 828 genes were differentially expressed in response to iodine exposure; 66% were upregulated, as were most of the highly enriched pathways (related to inflammatory-immune response, antioxidant response, xenobiotic metabolism, platelet activation and calcium signaling). About 300 genes were differentially expressed between WT and KO mice; highly enriched pathways were related to glutathione and xenobiotic metabolism, Ahr signaling and Nrf2 signaling and were all downregulated in KO mice. Analysis of the potential upstream regulators of these highly enriched pathways revealed that Nrf2 and NfkB are major regulators of the antioxidant and inflammatory response induction upon iodine exposure and that Tgfβ-Smad cascade regulates the induction of fibrosis signaling. Last, we performed an analysis limited to already known thyroid pathways. A few genes were enriched following this method; upregulation of Duoxa1 (hydrogen peroxide generator) and downregulation of Nis (sodium iodide symporter) upon iodine exposure, which are expected responses, and the downregulation of thyroglobulin and upregulation of Duoxa1 in KO mice that confirm our previous findings. In conclusion, Nrf2-driven cytoprotective response is upregulated after iodine overload along with induction of inflammatory pathways. Nrf2 regulates transcriptomic responses in the thyroid, including a small but significant part of the response to iodine challenge. Hence, Nrf2 can be considered a novel player in the frontiers of thyroid antioxidant response and thyroid economy.


2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi137-vi137
Author(s):  
Mi-Yeon Jung ◽  
Benjamin Himes ◽  
Luz Cumba-Garcia ◽  
Ian Parney

Abstract Glioblastoma (GBM) is the most common and aggressive primary brain tumor. Median survival is 15 months despite surgery, radiation, and chemotherapy. Immunotherapy is promising but GBM-mediated immunosuppression remains a barrier. Recently, extracellular vesicles (EVs) have been implicated in GBM-mediated immunosuppression through expression of the immune checkpoint molecule PD-L1. Data from our group has suggested this is predominantly through induction of immunosuppressive monocytes including myeloid-derived suppressor cells (MDSCs) and non-classical monocytes (NCMs). PD-L1 expression is increased in most nucleated cells following IFN-γ exposure. We, therefore, sought to determine if IFN-γ exposure would result in super-induction of immunosuppressive GBM EVs. EVs were harvested in vitro from matched differentiated and stem-like human GBM cell lines +/- IFN-γ. IFN-γ exposure did not alter EV production or expression of common EV markers but increased PD-L1 expression in EVs from differentiated but not stem-like GBM cells. In keeping with our earlier findings, no direct inhibition of T cell proliferation by stem-like or differentiated GBM EVs was observed regardless of IFN-γ exposure or PD-L1 expression. In contrast, differentiated but not stem-like GBM cell EVs induced MDSC and NCM differentiation from normal monocytes. This was increased following IFN-γ exposure and was dependent upon PD-L1 expression. Monocytes exposed to differentiated but not stem-like GBM cell EVs inhibited T cell proliferation in a similar manner (increased with IFN-γ exposure, decreased with PD-L1 knockdown). Thus, IFN-γ exposure results in super-induction of immunosuppressive EVs from differentiated but not stem-like GBM cells that increase MDSC and NCM differentiation in normal monocytes and increase their ability to inhibit T cell proliferation. These effects are dependent upon PD-L1 up-regulation induced by IFN-γ. This may be an important mechanism GBMs utilize to suppress anti-tumor T cell responses that are typically accompanied by increased IFN-γ expression.


2020 ◽  
Author(s):  
Vikram Sunkara ◽  
Gitta A. Heinz ◽  
Frederik F. Heinrich ◽  
Pawel Durek ◽  
Ali Mobasheri ◽  
...  

AbstractObjectiveDue to the small size of the murine knee joint, extracting the chondrocyte transcriptome from articular cartilage (AC) is a major technical challenge. In this study, we demonstrate a new and pragmatic approach of combining bulk RNA-sequencing (RNA-seq) and single cell (sc)RNA-seq to address this problem.DesignWe propose a new cutting strategy of the murine femur which produces three segments with a predictable mixed cell populations, where one segment contains AC and growth plate (GP) chondrocytes, another contains GP chondrocytes, and the last segment contains only bone and bone marrow. We analysed the bulk RNA-seq of the different segments to find common and distinct genes between the segments. Then, the segment containing AC chondrocytes was digested and analysed via scRNA-seq.ResultsDifferential expression analysis using bulk RNA-seq identified 350 candidate chondrocyte gene in the AC segment. Gene set enrichment analysis of these genes revealed biological processes related- and non-related to chondrocytes, including, cartilage development (adj. p-value: 3.45E-17) and endochondral bone growth (adj. p-value 1.22E-4), respectively. ScRNA-seq of the AC segment found a cluster of 131 cells containing mainly chondrocytes. This cluster had 759 differentially expressed genes which enriched for extracellular matrix organisation (adj. p-value 7.76E-40) and other joint development processes. The intersection of the gene sets of bulk- and scRNA-seq contained 75 genes, where all but ten genes were previously implicated in cartilage homeostasis or osteoarthritis (OA) progression.ConclusionsOur approach has the potential to detect the scarce disease phenotypes of chondrocytes in murine OA models.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Matthew Chung ◽  
Vincent M. Bruno ◽  
David A. Rasko ◽  
Christina A. Cuomo ◽  
José F. Muñoz ◽  
...  

AbstractAdvances in transcriptome sequencing allow for simultaneous interrogation of differentially expressed genes from multiple species originating from a single RNA sample, termed dual or multi-species transcriptomics. Compared to single-species differential expression analysis, the design of multi-species differential expression experiments must account for the relative abundances of each organism of interest within the sample, often requiring enrichment methods and yielding differences in total read counts across samples. The analysis of multi-species transcriptomics datasets requires modifications to the alignment, quantification, and downstream analysis steps compared to the single-species analysis pipelines. We describe best practices for multi-species transcriptomics and differential gene expression.


Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1745
Author(s):  
Ben-Ben Miao ◽  
Su-Fang Niu ◽  
Ren-Xie Wu ◽  
Zhen-Bang Liang ◽  
Bao-Gui Tang ◽  
...  

Pearl gentian grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂) is a fish of high commercial value in the aquaculture industry in Asia. However, this hybrid fish is not cold-tolerant, and its molecular regulation mechanism underlying cold stress remains largely elusive. This study thus investigated the liver transcriptomic responses of pearl gentian grouper by comparing the gene expression of cold stress groups (20, 15, 12, and 12 °C for 6 h) with that of control group (25 °C) using PacBio SMRT-Seq and Illumina RNA-Seq technologies. In SMRT-Seq analysis, a total of 11,033 full-length transcripts were generated and used as reference sequences for further RNA-Seq analysis. In RNA-Seq analysis, 3271 differentially expressed genes (DEGs), two low-temperature specific modules (tan and blue modules), and two significantly expressed gene sets (profiles 0 and 19) were screened by differential expression analysis, weighted gene co-expression networks analysis (WGCNA), and short time-series expression miner (STEM), respectively. The intersection of the above analyses further revealed some key genes, such as PCK, ALDOB, FBP, G6pC, CPT1A, PPARα, SOCS3, PPP1CC, CYP2J, HMGCR, CDKN1B, and GADD45Bc. These genes were significantly enriched in carbohydrate metabolism, lipid metabolism, signal transduction, and endocrine system pathways. All these pathways were linked to biological functions relevant to cold adaptation, such as energy metabolism, stress-induced cell membrane changes, and transduction of stress signals. Taken together, our study explores an overall and complex regulation network of the functional genes in the liver of pearl gentian grouper, which could benefit the species in preventing damage caused by cold stress.


2021 ◽  
Vol 11 (8) ◽  
pp. 3562
Author(s):  
Yong Jin Lee ◽  
Sang Yong Park ◽  
Dae Yeon Kim ◽  
Jae Yoon Kim

Preharvest sprouting (PHS) is a key global issue in production and end-use quality of cereals, particularly in regions where the rainfall season overlaps the harvest. To investigate transcriptomic changes in genes affected by PHS-induction and ABA-treatment, RNA-seq analysis was performed in two wheat cultivars that differ in PHS tolerance. A total of 123 unigenes related to hormone metabolism and signaling for abscisic acid (ABA), gibberellic acid (GA), indole-3-acetic acid (IAA), and cytokinin were identified and 1862 of differentially expressed genes were identified and divided into 8 groups by transcriptomic analysis. DEG analysis showed the majority of genes were categorized in sugar related processes, which interact with ABA signaling in PHS tolerant cultivar under PHS-induction. Thus, genes related to ABA are key regulators of dormancy and germination. Our results give insight into global changes in expression of plant hormone related genes in response to PHS.


2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Xueyi Dong ◽  
Luyi Tian ◽  
Quentin Gouil ◽  
Hasaru Kariyawasam ◽  
Shian Su ◽  
...  

Abstract Application of Oxford Nanopore Technologies’ long-read sequencing platform to transcriptomic analysis is increasing in popularity. However, such analysis can be challenging due to the high sequence error and small library sizes, which decreases quantification accuracy and reduces power for statistical testing. Here, we report the analysis of two nanopore RNA-seq datasets with the goal of obtaining gene- and isoform-level differential expression information. A dataset of synthetic, spliced, spike-in RNAs (‘sequins’) as well as a mouse neural stem cell dataset from samples with a null mutation of the epigenetic regulator Smchd1 was analysed using a mix of long-read specific tools for preprocessing together with established short-read RNA-seq methods for downstream analysis. We used limma-voom to perform differential gene expression analysis, and the novel FLAMES pipeline to perform isoform identification and quantification, followed by DRIMSeq and limma-diffSplice (with stageR) to perform differential transcript usage analysis. We compared results from the sequins dataset to the ground truth, and results of the mouse dataset to a previous short-read study on equivalent samples. Overall, our work shows that transcriptomic analysis of long-read nanopore data using long-read specific preprocessing methods together with short-read differential expression methods and software that are already in wide use can yield meaningful results.


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