Germinal centers (GCs) are clusters of activated B cells built on stromal cells known as follicular dendritic cells (FDCs). In the Peyers patches (PPs), GCs are chronically induced by bacteria and are the major sites for generation of gut IgA immune responses. Whether FDCs directly contribute to the IgA production in PP GCs is unknown.
The sensing of environmental stimuli by follicular dendritic cells promotes immunoglobulin A generation in the gut.
Specimen part
View SamplesDespite their key role in immunity our understanding of primary and secondary lymphoid stromal cell heterogeneity and ontogeny remains limited. Here, using genome-wide expression profiling and phenotypic and localization studies, we identify a functionally distinct subset of BP3-PDPN+PDGFR+/+CD34+ stromal adventitial cells in both lymph nodes and thymus that is located within the perivascular niche surrounding PDPN-PDGFR+/-Esam-1+ITGA7+ pericytes. In re-aggregate organ grafts adult CD34+ adventitial cells gave rise to multiple thymic and lymph node mesenchymal subsets including pericytes, FRC-, MRC- and FDC-like cells, the development of which was lymphoid environment dependent. During thymic ontogeny pericytes developed from a transient population of BP3-PDPN+PDGFR+/+CD34-/lo anlage-seeding progenitors that subsequently up-regulated CD34 and we provide evidence suggesting that similar embryonic progenitors give rise to lymph node mesenchymal subsets. These findings extend the current understanding of lymphoid mesenchymal cell heterogeneity and highlight a role of the CD34+ vascular adventitia as a potential ubiquitous source of lymphoid stromal precursors in postnatal tissues.
Context-Dependent Development of Lymphoid Stroma from Adult CD34(+) Adventitial Progenitors.
Age, Specimen part
View SamplesMesenchymal stromal cells (MSC) are currently being evaluated in numerous preclinical and clinical cell-based therapy studies. Furthermore, there is an increasing interest in exploring alternative uses of these cells in disease modelling, pharmaceutical screening and regenerative medicine by applying reprogramming technologies. However, the limited availability of MSCs from various sources, restricts their use. Term amniotic fluid has been proposed as an alternative source of MSCs. Previously, only low volumes of term fluid and its cellular constituents have been collected, and current knowledge of the MSCs derived from this fluid is limited. In this study, we collected amniotic fluid at term using a novel collection system and evaluated amniotic fluid MSC content and their characteristics, including their feasibility to undergo cellular reprogramming.
Term amniotic fluid: an unexploited reserve of mesenchymal stromal cells for reprogramming and potential cell therapy applications.
Specimen part
View SamplesBone marrow mesenchymal stem cells (MSC) were adipogenically differentiated followed by dedifferentiation. We are interested to know the new fat markers, adipogenic signaling pathways and dedifferentiation signaling pathways.Furthermore we are also intrested to know that how differentiated cells convert into dedifferentiated progenitor cells. To address these questions, MSC were adipogenically differentiated, followed by dedifferentiation. Finally these dedifferentiated cells were used for adipogenesis, osteogenesis and chondrogenesis. Histology, FACS, qPCR and GeneChip analyses of undifferentiated, adipogenically differentiated and dedifferentiated cells were performed. Regarding the conversion of adipogenically differentiated cells into dedifferentiated cells, gene profiling and bioinformatics demonstrated that upregulation (DHCR24, G0S2, MAP2K6, SESN3) and downregulation (DST, KAT2, MLL5, RB1, SMAD3, ZAK) of distinct genes play a curcial role in cell cycle to drive the adipogenically differentiated cells towards an arrested state to narrow down the lineage potency. However, the upregulation (CCND1, CHEK, HGF, HMGA2, SMAD3) and downregulation (CCPG1, RASSF4, RGS2) of these cell cycle genes motivates dedifferentiation of adipogenically differentiated cells to reverse the arrested state. We also found new fat markers along with signaling pathways for adipogenically differentiated and dedifferentiated cells, and also observed the influencing role of proliferation associated genes in cell cycle arrest and progression.
Transdifferentiation of adipogenically differentiated cells into osteogenically or chondrogenically differentiated cells: phenotype switching via dedifferentiation.
Specimen part
View SamplesHaematopoietic stem cells can differentiate into all blood cell types. In this process, cells become progressively restricted to a single cell type. The order in which differentiating cells loose lineage potential, and the prospective isolation of cells with a defined potential remains a long-standing question. We performed gene expression analysis of haematopoietic cells from Gata1-EGFP reporter mice, leading to a model for hematopoiesis where the initial lineage decision consists of a seperation of erythroid/megakaryocyte/mast cell/eosinophil potential from lymphopoietic/monocyte/neutrophil potential Overall design: Find unbiased heterogeneity in the preGM hematopoietic progenitor population
Distinct myeloid progenitor-differentiation pathways identified through single-cell RNA sequencing.
Specimen part, Cell line, Subject
View SamplesHaematopoietic stem cells can differentiate into all blood cell types. In this process, cells become progressively restricted to a single cell type. The order in which differentiating cells loose lineage potential, and the prospective isolation of cells with a defined potential remains a long-standing question.
Distinct myeloid progenitor-differentiation pathways identified through single-cell RNA sequencing.
Specimen part
View SamplesAutologous chondrocyte transplantation (ACT) is a routine technique to regenerate focal cartilage lesions. However, patients with osteoarthritis (OA) are lacking an appropriate long-lasting treatment alternative, partly since it is not known if chondrocytes from OA patients have the same chondrogenic differentiation potential as chondrocytes from donors not affected by OA. Articular chondrocytes from patients with OA undergoing total knee replacement (Mankin Score >3, Ahlbck Score >2) and from patients undergoing ACT, here referred to as normal donors (ND), were isolated applying protocols used for ACT. Their chondrogenic differentiation potential was evaluated both in high-density pellet and scaffold (Hyaff-11) cultures by histological proteoglycan assessment (Bern Score) and immunohistochemistry for collagen types I and II. Chondrocytes cultured in monolayer and scaffolds were subjected to gene expression profiling using genome-wide oligonucleotide microarrays. Expression data were verified by using quantitative RT-PCR. Chondrocytes from ND and OA donors demonstrated accumulation of comparable amounts of cartilage matrix components, including sulphated proteoglycans and collagen types I and II. The mRNA expression of cartilage markers (COL2A1, COMP, aggrecan, CRTL1, SOX9) and genes involved in matrix synthesis (biglycan, COL9A2, COL11A1, TIMP4, CILP2) was highly induced in 3D cultures of chondrocytes from both donor groups. Genes associated with hypertrophic or OA cartilage (COL10A1, RUNX2, periostin, ALP, PTHR1, MMP13, COL1A1, COL3A1) were not significantly regulated between the two groups of donors. The expression of 661 genes, including COMP, FN1, and SOX9, were differentially regulated between OA and ND chondrocytes cultured in monolayer. During scaffold culture, the differences diminished between the OA and ND chondrocytes, and only 184 genes were differentially regulated. Only few genes were differentially expressed between OA and ND chondrocytes in Hyaff-11 culture. The risk of differentiation into hypertrophic cartilage does not seem to be increased for OA chondrocytes. Our findings suggest that the chondrogenic capacity is not significantly affected by OA and OA chondrocytes fulfill the requirements for matrix-associated ACT.
Chondrogenic differentiation potential of osteoarthritic chondrocytes and their possible use in matrix-associated autologous chondrocyte transplantation.
Specimen part
View SamplesFLT3-ITDs Introduce a Myeloid Differentiation and Transformation Bias in Lympho-myeloid Multipotent Progenitors
FLT3-ITDs instruct a myeloid differentiation and transformation bias in lymphomyeloid multipotent progenitors.
Sex, Specimen part
View SamplesRheumatoid arthritis (RA) leads to progressive destruction of articular structures. Despite recent progress in controlling inflammation and pain, little cartilage repair has yet been observed. This in vitro study aims to determine the role of chondrocytes in RA-related cartilage destruction and antirheumatic drug-related regenerative processes. Human chondrocytes were three-dimensionally cultured in alginate beads. To determine the RA-induced gene expression pattern, human chondrocytes were stimulated with supernatant of RA synovial fibroblasts (RASF) and normal donor synovial fibroblasts (NDSF), respectively. To examine antirheumatic drug response signatures, human chondrocytes were stimulated with supernatant of RASF that have been treated with disease-modifying antirheumatic drugs (DMARD; azathioprine, sodium aurothiomalate, chloroquine phosphate, methotrexate), non-steroidal anti-inflammatory drugs (NSAID; piroxicam, diclofenac) or steroidal anti-inflammatory drugs (SAID; methylprednisolone, prednisolone). Genome-wide expression profiling with oligonucleotide microarrays was used to determine differentially expressed genes. Real-time RT-PCR and ELISA were performed for validation of microarray data. Following antirheumatic treatment, microarray analysis disclosed a reverted expression of 94 RA-induced chondrocyte genes involved in inflammation/NF-B signalling, cytokine/chemokine activity, immune response, proliferation/differentiation and matrix remodelling. Hierarchical clustering analysis showed that treatment of RASF with the DMARD azathioprine, gold sodium thiomalate and methotrexate resulted in chondrocyte gene expression signatures that were closely related to the healthy pattern. Treatment with the SAID methylprednisolone and prednisolone strongly reverted the RA-related chondrocyte gene expression, in particular the expression of genes involved in inflammation/NF-B and cytokine/chemokine activity. The NSAID piroxicam and diclofenac and the DMARD chloroquine phosphate had only moderate to marginal effects. Pathway analysis determined major mechanisms of drug action, for example pathways of cytokine-cytokine receptor interaction, TGF-/TLR/Jak-STAT signalling and ECM-receptor interaction were targeted. This in vitro study provides a comprehensive molecular insight into the antirheumatic drug response signatures in human chondrocytes, thereby revealing potential molecular targets, pathways and mechanisms of drug action involved in chondrocyte regeneration. Thus, the present study may contribute to the development of novel therapeutic chondro-protective compounds and strategies.
Antirheumatic drug response signatures in human chondrocytes: potential molecular targets to stimulate cartilage regeneration.
No sample metadata fields
View SamplesWe have studied the expression profile of 3D cultured human chondrocytes that were stimulated with supernatant of synovial fibroblasts derived from a RA patient (RASF=HSE cell line) and from a normal donor (NDSF=K4IM cell line), respectively. For this purpose, passage 2 human chondrocytes were cultured for 14 days in alginate beads and subsequently stimulated for 48 hours with supernatant of RASF and NDSF. Baseline expression was determined of unstimulated chondrocytes. Differential genome-wide microarray analysis of RASF and NDSF stimulated chondrocytes disclosed a distinct expression profile related to cartilage destruction involving marker genes of inflammation (COX-2), NF-kappa B signaling pathway (TLR2), cytokines/chemokines and receptors (CXCL1-3, CCL20, CXCL8, CXCR4, IL-6, IL-1beta), matrix degradation (MMP-10, MMP-12) and suppressed matrix synthesis (COMP). Thus, transcriptome profiling of RASF and NDSF stimulated chondrocytes revealed a disturbed catabolic-anabolic homeostasis of chondrocyte function. This study provides a comprehensive insight into the molecular regulatory processes induced in human chondrocytes during RA-related cartilage destruction.
Key regulatory molecules of cartilage destruction in rheumatoid arthritis: an in vitro study.
No sample metadata fields
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