Ceramide blockade in murine hematopoietic stem cells
Ontology highlight
ABSTRACT: Hematopoietic stem and progenitor cells (HSPCs) rely upon cellular crosstalk, including extracellular vesicles (EVs) for lifelong niche occupancy and cellular function. Vesicle secretion is tightly linked to intracellular homeostasis; however, these mechanisms are poorly understood in HSPCs, particularly at the single-cell level. In this study, we target ceramide-dependent EV secretion by pharmacologic blockade in ex vivo expanded HSPCs. We use these cells to investigate single-cell resolution of short-term and delayed transcriptional changes induced by ceramide-EV inhibition.
Project description:Cellular crosstalk within the bone marrow niche maintains hematopoietic stem and progenitor cell (HSPC) integrity and safeguards lifelong blood and immune cell production. Deeper understanding of reciprocal niche signals governing crucial properties of HSPCs is relevant to the pathophysiology of blood disorders and improving HSPC transplantation. Extracellular vesicles (EVs) are key factors of the HSPC secretome, providing signals that regulate homeostasis and stemness. Here we demonstrate ex vivo blockade of ceramide-dependent vesicle secretion from HSPCs activates an integrated stress response (ISR), promoting downstream mTOR inhibition and metabolic quiescence. Crucially, ceramide-EV depletion leads to striking improvements in long-term transplantation. The aggregate findings link ceramide-dependent EV secretion and the ISR as a regulatory dyad guarding HSPC homeostasis and long-term fitness. Translationally, these data support exploration of ceramide inhibition during ex vivo maintenance of HSPCs for adoptive transfer.
Project description:Osteolineage cells represent one of the critical bone marrow niche components that support maintenance of hematopoietic stem and progenitor cells (HSPCs). Recent studies demonstrate that extracellular vesicles (EVs) regulate stem cell development via horizontal transfer of bioactive cargo, including microRNAs (miRNAs). Here, we characterize the miRNA profile of EVs secreted by human osteoblasts and study their biological effect of on human umbilical cord blood-derived CD34+ HSPCs by sequencing, gene expression and biochemical analyses. Using next-generation sequencing we show that osteoblast-derived EVs contain highly abundant miRNAs specifically enriched in EVs, including critical regulators of hematopoietic proliferation (e.g., miR-29a). EV treatment of CD34+ HSPCs alters the expression of candidate miRNA targets, such as HBP1, BCL2 and PTEN. Furthermore, EVs enhance proliferation of CD34+ cells and their immature subsets in growth factor-driven ex vivo expansion cultures. Importantly, EV-expanded cells retain their differentiation capacity in vitro and show successful engraftment in NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) mice in vivo. These discoveries reveal a novel osteoblast-derived EV-mediated mechanism for regulation of HSPC proliferation and warrant consideration of EV-miRNAs for the development of expansion strategies to treat hematological disorders.
Project description:Cancer cells secrete extracellular vesicles (EVs) to regulate cells in the tumor microenvironment for their own benefit to grow and survive in the patient’s body. Although emerging evidence has demonstrated the molecular mechanisms of EV release, regulating cancer-specific EV secretion remains challenging . In this study, we applied a microRNA (miRNA) library to reveal the universal mechanisms of EV secretion in cancer cells. Here, we identified miR-891b and its direct target gene, phospho-aminotransferase 1 (PSAT1), which promotes EV secretion through the serine-ceramide synthesis pathway. Inhibition of PSAT1 affected EV secretion in multiple types of cancer, suggesting that the miR-891b/PSAT1 axis shares a common mechanism of cancer EV secretion.
Project description:Oncogenes reprogram multiple metabolic phenotypes of cancer cells including the balance between anabolic and catabolic processes, mechanisms of nutrient uptake, and choices in nutrient utilization. Here, we explore how different oncogenes regulate biomass loss via extracellular vesicle release. We use isogenic mammary breast epithelial cells transformed with a panel of oncogenes found commonly mutated, amplified or overexpressed in multiple cancers. We observe an increase in extracellular vesicle (EV) release upon oncogenic transformation, with MYC and AURKB oncogenes eliciting the highest number of EVs produced. Oncogene expression altered the protein composition of released EVs. Likewise, miRNAs were differentially sorted into EVs in an oncogene-specific manner. We performed an integrated pathway analysis of metabolites and gene expression across different oncogene-expressing cells and identified that ceramide-sphingosine metabolism was broadly deregulated, especially in MYC overexpressing cells. Inhibition of neutral sphingomyelinases (N-SMase) resulted in significant decrease in EV production in MYC high cells, while ESCRT-dependent small EV production predominated in AURKB cells.
Project description:RNA transfer via extracellular vesicles (EVs) influences cell phenotypes; however, lack of information regarding biogenesis of RNA-containing EVs has limited progress in the field. Here, we identify endoplasmic reticulum membrane contact sites (ER MCS) as platforms for generation of RNA-containing EVs. We identify a subpopulation of small EVs that is highly enriched in RNA and regulated by the ER MCS linker protein VAP-A. Functionally, VAP-A-regulated EVs are critical for miR-100 transfer between cells and in vivo tumor formation. Lipid analysis of VAP-A-knockdown EVs revealed reductions in the EV biogenesis lipid ceramide. Knockdown of the VAP-A-binding ceramide transfer protein CERT led to similar defects in EV RNA content. Imaging experiments revealed that VAP-A promotes lumenal filling of multivesicular bodies (MVBs). CERT localizes to MVBs, and the ceramide-generating enzyme neutral sphingomyelinase 2 colocalizes with VAP-A-positive ER. We propose that ceramide transfer via VAP-A-CERT linkages drives biogenesis of a select RNA-containing population.
Project description:Extracellular vesicle(EV) secretion and capture is an important method of communication between cells. Melanocytes and their surrounding keratinocytes form epidermal melanin units in the thin, outermost layer of the skin to protect the skin from ultraviolet radiation damage. It is important to understand the mechanisms by which changes in melanocyte EV signal transduction influence pigmentation. EVs from melanocytes were extracted and used to investigate changes in the miRNA profile of EVs, and the effect of exosomal miR-28-3p on keratinocyte with transcriptomics was analyzed by RNA-seq analysis.Our results indicate that the content of miR-28 in EVs may be reduced to induce keratinocytes to prevent carcinogenesis, resist infection and prevent premature apoptosis.
Project description:Extracellular vesicles (EVs) enable cell-to-cell communication in the nervous system essential for development and adult function. Endosomal Sorting Complex Required for Transport (ESCRT) complex proteins regulate EV formation and release. Recent work shows loss of function (LOF) mutations in, CHMP1A, which encodes one ESCRT-III member, cause autosomal recessive microcephaly with pontocerebellar hypoplasia in humans (Mochida et al., 2012). Here we show CHMP1A is required for maintenance of progenitors in human cerebral organoids and that mouse Chmp1a is required for progenitor proliferation in cortex and cerebellum and specifically for sonic hedgehog (SHH) mediated proliferation through SHH secretion. CHMP1A mutation reduces intraluminal vesicle (ILV) formation in multivesicular bodies (MVBs), and EV release. SHH protein is present on a subset of EVs marked by a unique set of proteins we call ART-EVs. CHMP1A’s requirement in formation of ART-EVs and other EVs provides a model to elucidate EV functions in multiple brain processes.
Project description:Extracellular vesicles (EVs) are known to be involved in inter-cellular communication during cancer progression, however, the biogenesis of EVs in cancer cells is not completely unveiled. It has been shown that microRNAs (miRNAs) regulated variety of physiological and pathological phenomena, thus, miRNAs could regulate the EV secretion. Here, we have performed high throughput miRNA-based screening to identify the regulators of EV secretion using ExoScreen assay. By this miRNA-based screening, we identified miR-26a, which was reported as tumor suppressive miRNA, was found to be an miRNA involved in EV secretion from prostate cancer (PCa) cells. To study the effect of miR-26a on gene expression in EV secretion, transcriptome analysis for miR-26a overexpressing PCa cell lines was performed.
Project description:Beyond forming bone, osteoblasts play pivotal roles in various biological processes, including hematopoiesis and bone metastasis. Extracellular vesicles (EVs) have recently been implicated in intercellular communication via transfer of proteins and nucleic acids between cells. Here, we focused on the proteomic characterization of non-mineralizing (NMOBs) and mineralizing (MOBs) human osteoblast (SV-HFOs) EVs and investigated their effect on human prostate cancer (PC3) cells by microscopic, proteomic and gene expression analyses. Proteomic analysis showed that 97% of the proteins were shared among NMOB and MOB EVs, and 30% were novel osteoblast-specific EV proteins. Label-free quantification demonstrated mineralization stage-dependent five-fold enrichment of 59 and 451 EV proteins in NMOBs and MOBs, respectively. Interestingly, bioinformatic analyses of the osteoblast EV proteomes and EV-regulated prostate cancer gene expression profiles showed that they converged on pathways involved in cell survival and growth. This was verified by in vitro proliferation assays where osteoblast EV uptake led to two-fold increase in PC3 cell growth compared to cell-free culture medium-derived vesicle controls. Our findings elucidate the mineralization stage-specific protein content of osteoblast-secreted EVs, show a novel way by which osteoblasts communicate with prostate cancer, and open up innovative avenues for therapeutic intervention. PC3 cells were treated with extracellular vesicles from non-mineralizing and mineralizing SV-HFOs for three different incubation times (4hrs, 24hrs, 48hr)
Project description:Acute myeloid leukemia (AML) is an aggressive and heterogeneous clonal disorder of hematopoietic stem/progenitor cells (HSPCs). It is not well known how leukemia cells alter hematopoiesis promoting tumor growth and leukemic niche formation. In this study, we investigated how AML deregulates the hematopoietic process of HSPCs through the release of extracellular vesicles (EVs). First, we found that AML cells released a heterogeneous population of EVs (AML-EVs) containing microRNAs involved in AML pathogenesis. Notably AML-EVs were able to influence the fate of HSPCs modifying their transcriptome. In fact, a gene expression profile of AML-EV-treated HSPCs identified approximately 923 down and 630 up-regulated genes involved in hematopoiesis/differentiation, inflammatory cytokine production and cell movement. Indeed, most of the downregulated genes are targeted by AML-EV-derived miRNAs. Furthermore, we demonstrated that AML-EVs were able to affect HSPCs phenotype, modifying several biological functions, such as inhibiting cell differentiation and clonogenicity, activating inflammatory cytokine production and compromising cell movement. Indeed, a redistribution of HSPC populations was observed in AML-EV treated cells with a significant increase in the frequency of common myeloid progenitors and a reduction in granulocyte-macrophage progenitors and megakaryocyte-erythroid progenitors. This effect was accompanied by a reduction in HSPC colony formation. AML-EV treatment of HSPCs increased the levels of CCL3, IL1B and CSF2 cytokines, involved in the inflammatory process and in cell movement, and decreased CXCR4 expression associated with a reduction of SDF-1 mediated-migration. In conclusion, this study demonstrates the existence of a powerful communication between AML cells and HSPCs, mediated by EVs, which suppresses normal hematopoiesis and potentially contributes to create a leukemic niche favorable to neoplastic development.