Project description:Direct contact with mesenchymal stromal impacts on migratory behavior and gene expression profile of CD133+ hematopoietic stem cells during ex-vivo expansion Objective: To investigate the impact of direct contact between mesenchymal stromal cells (MSCs) and CD133+ hematopoietic stem cells (HSCs) in terms of expansion potential differentiation, migratory capacity and gene expression profile. Methods: CD133+ purified HSCs were cultured for 7 days on subconfluent MSCs supplemented with growth factor containing medium. After ex-vivo expansion, non-adherent and adherent cells were collected and analyzed separately. Results: The adherent cells were found to have a more immature phenotype compared to the non-adherent fraction. CXCR4 was up regulated in the adherent fraction which was associated with a higher migration capacity towards a SDF-1 gradient. CFU-GM and LTC-IC assays demonstrated a higher clonogenicity and repopulating capacity of the adherent fraction. Genes involved in adhesion, cell cycle control, motility, self-renewal and apoptosis were expressed at a higher level in the adherent fraction. Conclusion: Adhesion and direct cell-cell contact with a MSC feeder layer supports ex-vivo expansion, migratory potential and stemness of CD133+ HSCs. Keywords: co-culture hematopoietic stem cells (HSCs) on mesenchymal stromal cells (MSCs)
Project description:Direct contact with mesenchymal stromal impacts on migratory behavior and gene expression profile of CD133+ hematopoietic stem cells during ex-vivo expansion Objective: To investigate the impact of direct contact between mesenchymal stromal cells (MSCs) and CD133+ hematopoietic stem cells (HSCs) in terms of expansion potential differentiation, migratory capacity and gene expression profile. Methods: CD133+ purified HSCs were cultured for 7 days on subconfluent MSCs supplemented with growth factor containing medium. After ex-vivo expansion, non-adherent and adherent cells were collected and analyzed separately. Results: The adherent cells were found to have a more immature phenotype compared to the non-adherent fraction. CXCR4 was up regulated in the adherent fraction which was associated with a higher migration capacity towards a SDF-1 gradient. CFU-GM and LTC-IC assays demonstrated a higher clonogenicity and repopulating capacity of the adherent fraction. Genes involved in adhesion, cell cycle control, motility, self-renewal and apoptosis were expressed at a higher level in the adherent fraction. Conclusion: Adhesion and direct cell-cell contact with a MSC feeder layer supports ex-vivo expansion, migratory potential and stemness of CD133+ HSCs. Keywords: co-culture hematopoietic stem cells (HSCs) on mesenchymal stromal cells (MSCs) Non-adherent and adherent fractions from three independent experiments were isolated and collected. Cells were stabilized in PreProtct™ buffer (Miltenyi Biotec, Germany) and stored at -80ºC. Samples were shipped to Miltenyi Biotec (Bergisch Gladbach, Germany) a Whole Human Genome expression analysis. Briefly RNA was extracted and overall quality of total RNA samples was checked via the Agilent 2100 Bioanalyzer platform (Agilent Technologies). RNA samples were amplified and labelled using the Agilent Low RNA Input Linear Amp Kit (Agilent Technologies). Non-adherent samples were pooled as “Non-adherent pool” and adherent samples were pooled as “adherent pool” and labelled with Cy3 and Cy5, respectively. Fluorescence signals of the hybridized Agilent Oligo Microarrays were detected using Agilent’s DNA microarray scanner and the microarray image files were processed with The Agilent Feature Extraction Software (FES).
Project description:One of the long-standing goals in the field has been to establish a culture system that would allow maintenance of HSC properties ex vivo. In the absence of such system, the ability to model human hematopoiesis in vitro has been limited, and there has been little progress in the expansion of human HSCs for clinical application. To that end, we defined a mesenchymal stem cell co-culture system based on a monoclonal OP9 stromal cell line (OP9M2), for expansion of clonally multipotent human HSPCs that were protected from apoptosis and immediate differentiation, and retained the HSPC phenotype. To identify the supportive mechanisms, we performed a genome-wide gene expression analysis of OP9M2 stromal cells and compared the expression to a non-supportive stomal line (BFC012). This co-culture system provides a new, well-defined platform for studying mechanisms involved in HSC-niche interactions and protection of critical HSC properties ex vivo. To determine the cellular identity and the supportive mechanism of the OP9M2 cells, we compared the OP9M2 cells with non-supportive BFC012 stromal cells using Affymetrix mouse microarrays.
Project description:Ex-vivo expanded mesenchymal stromal cells (MSCs) are increasingly used for paracrine support of hematopoietic stem cell (HSC) regeneration, but inconsistent outcomes have been the huddle for on-going clinical trials. Here, we hypothesized that the heterogeneity in the niche activity of manufactured MSCs can be a parameter for variable outcomes in MSC-based cell therapy. We first screened MSC culture medium and found that serum batches caused larger variations in colony forming unit-fibroblast (CFU-F) content of MSCs than individual donor variations. The culture conditions supporting high (stimulatory) and low (non-stimulatory) CFU-F caused distinct niche activity of MSCs; MSCs under stimulatory condition exhibited higher level expression of cross-talk molecules (Jagged-1 and CXCL-12) and higher support for HSCS during long-term culture than MSCs under non-stimulatory culture. Moreover, the effects of MSCs enhancing hematopoietic engraftment were only visible when HSCs were co-transplanted with MSCs expanded under stimulatory, but not non-stimulatory conditions. However, these differences of MSCs were readily reversed by switching the culture mediums, indicating their distinct functional state, rather than clonal heterogeneity. Accordingly, transcriptomic analysis showed distinct gene set enrichment between the different MSCs and revealed distinct upstream signaling pathways such as inhibition of P53 and activation of ATF4 for MSCs under stimulatory conditions. Taken together, our study shows that the heterogeneity in the niche activity of MSCs can be created during ex-vivo expansion to cause a difference in the hematopoietic engraftment and raise the possibility that MSCs can be pre-screened for more predictable outcomes in clinical trials of MSCs. Total RNA obtained from isolated human mesenchymal stromal cells. To compare stimulatory (SS) serum and non-stimulatory (NSS) serums, MSCs had been maintained in each serum media were sub-cultured for at least two passages before analysis.
Project description:The Notch signaling pathway plays a critical role in regulating the proliferation and differentiation of stem and progenitor cells including hematopoietic stem and progenitor cells (HSPCs). Notch receptors and ligands are expressed in BM stromal and hematopoietic cells. A large body of evidence has demonstrated that activating Notch signaling enhances HSCs self-renewal and facilitates its expansion ex vivo. We report that an endothelium-targeted soluble Notch ligand, the DSL domain of mouse Delta-like 1 fused with a RGD motif (mD1R), efficiently promotes the expansion ex vivo of mouse bone marrow HSPCs in a Notch signaling and endocytosis dependent manner. HSPCs expanded in the presence of mD1R kept long-term HSPC repopulation capacity. We used microarrays to compare the gene expression profiles of HSPCs expanded in the presence of PBS and mD1R. KSL cells were plated on Human umbilical vein endothelial cells (HUVECs) and cultured in a serum-free medium supplemented with a cocktail containing 5 types of mouse cytokines (m5GF) in the presence of PBS or mD1R for 7 days. Then KSL cells were sorted from these cultured hematopoietic cells for RNA extraction and hybridization on Affymetrix microarrays. The experiments were repeated 3 times.
Project description:Despite the inclusion of inherited myeloid malignancies as a separate entity in the WHO Classification, our understanding of the etiology of familial leukemia remains limited. ERCC6L2-deficiency is a rare, life-threatening inherited condition that gives rise to bone marrow failure (BMF), myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) resulting from germline mutations in DNA repair factor ERCC6L2. Here we employ a lentiviral shRNA approach to functionally characterize the impact of ERCC6L2 loss on hematopoietic stem/progenitor cells (HSPCs) and mesenchymal stromal cells (MSCs). By combining cell culture assays and transcriptomic analysis of knockdown and ERCC6L2-mutated patient cells, we find that ERCC6L2-deficiency reduces HSPC clonogenic potential and delays erythropoiesis, while in MSCs it induces a significant lineage skewing, with increased osteogenesis and suppressed adipogenesis. Altogether, we demonstrate that ERCC6L2-deficiency impacts both hematopoietic and stromal compartments, and that our ex vivo model recapitulates patient phenotypes, providing a robust system to study germline mutations in hematological malignancies.
Project description:Mesenchymal stromal cells (MSC) are crucial components of the bone marrow (BM) microenvironment essential for regulating self-renewal, survival and differentiation of hematopoietic stem/progenitor cells (HSPC) in the stem cell niche. MSC are functionally and phenotypically altered in myelodysplastic syndromes (MDS), contributing to disease progression. MDS MSC do not harbor recurrent genetic alterations but have been shown to exhibit an altered methylome compared to MSC from healthy controls. We examined growth, differentiation and HSPC-supporting capacity of ex vivo expanded MSC from MDS patients in comparison to age-matched healthy controls after direct treatment in vitro with the hypomethylating agent azacitidine (AZA). We show that AZA exerts a direct effect on MSC by modulating their differentiation potential. Osteogenesis was significantly boosted in healthy MSC while adipogenesis was inhibited in both healthy and MDS MSC. In co-culture experiments, both AZA treated MDS MSC and healthy MSC exhibited enhanced support of non-clonal HSPC which was associated with increased cell cycle induction. Conversely, clonal MDS HSPC were inhibited by contact with AZA treated MSC. RNA-sequencing analyses of stromal cells revealed changes in pathways essential for HSPC support as well as in immune regulatory pathways. In sum, our data demonstrate that AZA treatment of stromal cells leads to upregulation of HSPC-supportive genes and cell cycle induction in co-cultured healthy HSPC, resulting in a proliferative advantage over clonal HSPC. Thus, restoration of functional hematopoiesis by AZA may be driven by activated stromal support factors in MSC providing cell cycle cues to healthy HSPC.
Project description:The Notch signaling pathway plays a critical role in regulating the proliferation and differentiation of stem and progenitor cells including hematopoietic stem and progenitor cells (HSPCs). Notch receptors and ligands are expressed in BM stromal and hematopoietic cells. A large body of evidence has demonstrated that activating Notch signaling enhances HSCs self-renewal and facilitates its expansion ex vivo. We report that an endothelium-targeted soluble Notch ligand, the DSL domain of mouse Delta-like 1 fused with a RGD motif (mD1R), efficiently promotes the expansion ex vivo of mouse bone marrow HSPCs in a Notch signaling and endocytosis dependent manner. HSPCs expanded in the presence of mD1R kept long-term HSPC repopulation capacity. We used microarrays to compare the gene expression profiles of HSPCs expanded in the presence of PBS and mD1R.
Project description:Mesenchymal stem/stromal cells from human pluripotent stem cell-derived brain organoid enhance the ex vivo expansion and maintenance of hematopoietic stem/progenitor cells
Project description:Stromal-epithelial interactions play a fundamental role in tissue homeostasis, controlling cell proliferation and differentiation. Not surprisingly, aberrant stromal-epithelial interactions contribute to malignancies. The goals and objectives of this study were 1.) to characterize and validate the molecular identity of human primary epithelial and stromal/mesenchymal breast cells maintained long-term in novel ex vivo culture conditions in serum free medium. 2.) To analyze changes in gene expression profiles of normal human primary epithelial and stromal/mesenchymal breast cells upon long-term ex vivo co-culture when compared to corresponding monocultures 3.) To study the dynamic reciprocity between normal human primary epithelial and stromal/mesenchymal breast cells. 4.) To identify critical molecular pathways and biomarkers controlling epithelial and/or stromal cell growth and quiescence. Human primary epithelial progenitor cells and mesenchymal stem cells bearing fluorescent tags were either co-cultured in novel ex vivo culture conditions on ECM coated meshes in serum free medium (M5) or cultured as monocultures in the same conditions for 30 days. The cultures were then dissociated and epithelial and stromal/mesenchymal cells from either co-cultures or monocultures separated by FACS. Gene expression profiling of epithelial or stromal/mesenchymal cells was performed. Clean gene expression profiles from three different epithelial and stromal/mesenchymal cell extracts either grown in co-cultures or monocultures were successfully obtained.