The temporal transcriptomic signature of cartilage formation
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ABSTRACT: To study chondrogenesis, we used a chicken limb bud model: We used RNA sequencing, and examined the differences between gene expression patterns during cartilage formation in micromass cultures of embryonic limb bud-derived progenitors. We sequenced in triplicate at Day 0,1,2,3,4,6,10,15 and also from mature birds.
Project description:Porcine chondroytes were stimulated with human recombinant CCL25 for 7 days with different concentrations (two samples). To mimic osteoarthritic like conditions, we also added TNF-alpha (two samples). Three samples were used as control samples. It is the first time, that chondrocytes were stimulated with CCL25 in order to find a save dose range for further experiments.
Project description:We applied ChIP-seq to explore the effect of missense mutations in TFs on their genome wide binding profile. Using a retroviral expression system in chicken mesenchymal stem cells, we elucidated the mechanism underlying a novel missense mutation in HOXD13 (Q317K) associated with a complex hand and foot malformation phenotype. The glutamine at position 317 (position 50 of the homeodomain) is conserved in most homeodomains, a notable exception being bicoid-type homeodomains that have K at this position. Our results show that the mutation results in a shift in the binding profile of the mutant towards a bicoid/PITX1 motif. Gene expression analysis and functional assays using in vivo overexpression studies confirm that the mutation results in a partial conversion of HOXD13 into a TF with bicoid/PITX1 properties. A similar shift was not observed with the mutation Q317R, which is associated with brachysyndactyly, suggesting that the bicoid/PITX1-shift observed for Q317K might be related to the severe clinical phenotype. For each wt or mutant transcription factor two independent biological replicates were used for ChIP-seq together with corresponding input DNA as reference samples. For expression analysis one RNA sample for each wt and mutant transcription factor was used and compared to the expression level of cells infected with empty vector by RNA-seq.
Project description:Articular cartilage is deprived of blood vessels and nerves, and the only cells residing in this tissue are chondrocytes. The molecular properties of the articular cartilage and the architecture of the extracellular matrix demonstrate a complex structure that differentiates on the depth of tissue. Osteoarthritis (OA) is a degenerative joint disease, the most common form of arthritis, affecting the whole joint. It is associated with ageing and affects the joints that have been continually stressed throughout life including the knees, hips, fingers, and lower spine region. OA is a multifactorial condition of joint characterised by articular cartilage loss, subchondral bone sclerosis, and inflammation leading to progressive joint degradation, structural alterations, loss of mobility and pain. Articular cartilage biology is well studied with a focus on musculoskeletal diseases and cartilage development. However, there are relatively few studies focusing on zonal changes in the cartilage during osteoarthritis.
Project description:The circadian clock in murine articular cartilage is a critical temporal regulatory mechanism for tissue homeostasis and osteoarthritis. However, translation of these findings into humans has been hampered by the difficulty in obtaining circadian time series human cartilage tissues. As such, a suitable model is needed to understand the initiation and regulation of circadian rhythms in human cartilage. We used a chondrogenic differentiation protocol on human embryonic stem cells (hESCs) as a proxy for early human chondrocyte development. Chondrogenesis was validated using histology and expression of pluripotency and differentiation markers. The molecular circadian clock was tracked in real time by lentiviral transduction of human clock gene luciferase reporters. Differentiation-coupled gene expression was assessed by RNAseq and differential expression analysis.
Project description:The main aim was to determine how polyadenylation site usage is affected by osteoarthritis. Age matched tissue samples were obtained from both healthy individuals and those with late stage osteoarthritis, total RNA was isolated and then QuantSeq Reverse library produced using commercial kit (Lexogen) before sequencing
Project description:Bovine articular chondrocytes were grown in micromass culture and were either untreated or treated with 5 ng TGF-b1/ml for 8 hours to identify genes regulated by TGF-b. Six total samples were analyzed. Three biological replicates of untreated bovine articular chondrocytes grown in micromass culture and three biological replicates of bovine articular chondrocytes grown in micromass culture and treated with 5ng TGF-b1/ ml for 8 hours.
Project description:Shh signal mediated by Gli family of transcription factors regulates digit growth and patterning in early limb development. Shh expression in the posterior margin of the limb bud defines the zone of polarizing activity. However, much less is know about downstream targets that mediate Shh signal functions. In this dataset, we include the expression data obtained from dissected anterior and posterior halves of mouse limb bud respectively. These data are used to obtain 889 transcripts that were upregulated 1.3 fold or more in the posterior limb bud, and 1189 transcripts that were enriched in the anterior limb bud at 1.3 fold or more. Two samples were analyzed. We generate pairwise comparisons between anterior and posterior limb tissues. Genes with a fold-change ≥1.3 were selected.
Project description:The aim of this study was to characterize the surfaceome of primary equine chondrocytes isolated from healthy joints following exposure to the pro-inflammatory cytokines interleukin-1-beta (IL-1β) and tumour necrosis factor-alpha (TNF-α). We employed combined methodology that we recently developed for investigating the surfaceome in stem cells. Membrane proteins were isolated using an aminooxy-biotinylation technique and analysed by mass spectrometry using high throughput shotgun proteomics. Amongst the 431 unique cell surface proteins identified, a high percentage of low-abundance proteins, such as ion channels, receptors and transporter molecules were detected. A high number of proteins exhibited different levels of expression following chondrocyte stimulation with pro-inflammatory cytokines. LPR-1, thrombospondin, VDAC1-2 and annexin A1 were chosen for further analysis and validation by western blotting as proteins of special interest. Our results provide, for the first time, a repository for proteomic data on differentially expressed low-abundance membrane proteins on the surface of chondrocytes in response to pro-inflammatory stimuli.
Project description:Osteoarthritis was induced in male wild-type and ColIITgcog (c/c) mice by destabilisation of the medial meniscus (DMM). c/c mice have increased ER stress in chondrocytes via the collagen II promoter driven expression of a misfolding protein, the cog form of thyroglobulin. RNA-sequencing of laser micro-dissected cartilage was performed at 2 weeks post-surgery (n=3/group).
Project description:Glucosamine proved to be a potent, broad-spectrum inhibitor of IL-1beta. Of the 2,813 genes whose transcription was altered by IL-1beta stimulation (p<0.0001), glucosamine significantly blocked the response in 2,055 (~73%). Glucosamine fully protected the chondrocytes from IL-1-induced expression of inflammatory cytokines, chemokines and growth factors as well as proteins involved in PGE2 and NO synthesis. It also blocked the IL-1-induced expression of matrix specific proteases such as MMPs -3,-9,-10,-12 and ADAMTS-1. Experiment Overall Design: Articular cartilage was isolated from the femoral heads of male Wistar rats under aseptic conditions. Chondrocytes were obtained by sequential digestion of the cartilage with pronase and type II collagenase. After filtration to remove tissue debris, the cells were cultured in 75-cm2 flasks in complete Dulbeccoâs Modified Eagle Medium (DMEM; supplemented with 10% fetal bovine serum and 1% penicillin-streptomycin at 37°C in a humidified atmosphere containing 5% CO2. Experiments were subsequently performed with second-passage cultures whereby the cells from the large cultures were trypsinized, pooled and seeded into twenty 25 cm2 flasks. These were then divided into 4 treatment groups to evaluate the effects of glucosamine and IL-1 on global transcription patterns.To the culture medium in half of the flasks, glucosamine, HCl was added to a final concentration of 20 mM. Six hours later, IL-1beta was added at 10 ng/ml to 5 of the flasks receiving glucosamine and to 5 of the untreated flasks. Fourteen hours post IL-1beta stimulation, total RNA was isolated individually from the respective cultures and microarray experiments processed.