Understanding early human knee joint development with a single cell RNAseq approach
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE209948 | GEO | 2025/07/28
REPOSITORIES: GEO
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Project description:Post traumatic osteoarthritis (PTOA) is a painful joint disease characterized by the degradation of bone, cartilage, and connective tissues. PTOA is initiated by trauma to joint-stabilizing tissues, such as the anterior cruciate ligament, medial meniscus or by intra-articular fractures. In humans, ~50% of joint injuries progress to chronic PTOA, while the rest spontaneously resolve. To understand molecular programs contributing to PTOA development, we examined injury-induced fluctuations in immune cell populations and transcriptional shifts by single-cell sequencing of synovial joints in PTOA -susceptible C57BL6/J (B6) and -resistant MRL/MpJ (MRL) mice. A potent myeloid driven anti-inflammatory response was discovered in MRL injured joints that significantly contrasted the pro-inflammatory signaling seen in B6 joints. We found Trem2+ macrophages classically described as M2 (CD206+Trem2+) to be enriched in the uninjured joints of MRL mice, and these populations were consistently elevated in this strain, post injury. To evaluate whether Trem2 is essential to macrophage-mediated homeostasis in the joint, we examined Trem2 deficient mice and determined that these mice develop spontaneous OA. Overall, these data suggest that the PTOA resistant MRL mouse strain displays enhanced capacity of clearing debris and apoptotic cells induced by inflammation after injury due to an increase in activated macrophages within the synovial tissue and joint space. Furthermore, we showed that Trem2 is essential for preserving cartilage homeostasis in B6, and we postulate that the elevated levels of Trem2+ joint-resident macrophages in MRL are in part responsible for the PTOA-resistant phenotype in this strain.
2024-12-31 | GSE220167 | GEO
Project description:Cells from the superficial (AACS), middle (AACM) and deep (AACD) adult articular cartilage zones and the intermediate (II) and outer (OI) interzone layers and the transient embryonic cartilage of the long bone anlagen (EC) at gestational day 40 were separately collected using laser capture microdissection and microarray analysis was performed to confirm appropriate layer selection.
2019-06-01 | GSE83273 | GEO
Project description:Osteoarthritis (OA) is a degenerative joint disease characterized by progressive cartilage loss, bone remodeling, synovial inflammation, and significant joint pain, often resulting in disability. Injury to the synovial joint such as the anterior cruciate ligament (ACL) tear is the major cause of OA in young adults. Currently, there are no approved therapies available to prevent joint degeneration or rebuild articular cartilage destroyed by OA, primarily because our understanding of the cellular and molecular changes that contribute to joint damage is very limited. The synovial joint is a complex structure composed of several tissues including articular cartilage, subchondral bone, synovium, synovial fluid, and tensile tissues including tendons and ligaments. In the present study, using single-cell RNA sequencing (scRNA-seq), we examined the cellular heterogeneity in articular cartilage from mouse knee joints and determined the knee joint injury-induced early molecular changes in the chondrocytes that could contribute to OA.
2021-06-19 | GSE172500 | GEO
Project description:Synovial joints are structures where two bones meet and essential for mobility. For example, knee joints allow flexion and extension in a single plan for stable walking motions, whereas phalangeal joints together with skeletal muscles facilitate fine motor movements in hands. Joint is enclosed in a capsule and lined by a synovial membrane inside. Articular cartilage covering bone surfaces provide a wear-resistant structure that reduces friction during movement. Meniscus acts like a shock absorber to avoid direct grinding between bone surfaces. Cruciate ligaments reinforce the integrity of a joint by mounting two bones in place and limit the degree of joint movement. All these complex structures with different shapes are fit within the joint capsule for purpose. We established lineage maps of individual joint lineages for human and mouse to understand the progenitors, transcriptional regulators, signaling cues and extracellular matrix (ECM) involved in each differentiation trajectory. We asked whether LGR5+ joint progenitor cells are presence in early stage and decline with maturation as in our findings of mouse, and whether LGR5 and COL22A1 demarcate the chondrogenic and ligamentogenic lineages in human.
2025-06-10 | GSE206303 | GEO
Project description:Human cartilage taken from young normal knees following anterior cruciate ligament repair and osteoarthritic cartilage; old normal (protected) and old osteoarthritic (unprotected) following total knee arthroplasty. Total RNA extracted using mirVana miRNA isolation kit (Life Technologies). The Affymetrix Flash Tag labelling kit was used to prepare samples for hybridisation onto Affymetrix miRNA 4.0 arrays.
2017-12-31 | E-MTAB-5716 | biostudies-arrayexpress
Project description:The synovial joint forms from a pool of progenitor cells in the interzone region of the future joint. Expression of Gdf5 and Wnt9a has been used to mark the earliest cellular processes in the formation of the interzone and the progenitor cells. However, progression and lineage specification toward the different tissues of the joint is not well understood. Here, by lineage tracing studies we identify a population of Lgr5+ interzone cells that contribute to the formation of cruciate ligaments, synovial membrane and articular chondrocytes of the joint. This is supported by single cell transcriptome analyses. Furthermore, we showed that Col22a1, a marker of early articular chondrocytes, co-expresses with Lgr5+ cells prior to cavitation as an important lineage marker specifying the progression towards articular chondrocytes. Lgr5+ cells contribute to the repair of a joint defect with the re-establishment of Col22a1 containing superficial layer.
2019-09-13 | GSE130919 | GEO
Project description:Objective: Joint formation begins with the establishment of an interzone within the cartilaginous anlagen of the future skeleton and both Gdf5 and Erg are proposed as regulators of chondrocyte differentiation during and post interzone formation. The aim of this study was to examine the relationship between Gdf5 and Erg expression and downstream effects on chondrocyte gene expression. Design: Erg expression was identified in mouse knee joints at E13.5. Expression and microarray analyses were performed using micromass cultures of murine C3H10T1/2 mesenchymal cells undergoing induced chondrogenesis in the presence of absence of Gdf5 and Erg. Results: At E13.5, Erg expression was found to surround epiphyseal chondrocytes and span the interzone up to the intermediate zone. Erg splice forms were expressed in micromass cultures, and their expression profile was altered by the addition of recombinant Gdf5 depending on the stage of differentiation. Overexpression of Erg-010 resulted in a downregulation of Col2a1 and Col10a1. Microarray analysis following Erg-010 overexpression identified two potential downstream targets, Ube2b and Osr2, which were also differentially regulated by Gdf5. Conclusion: Erg regulation by Gdf5 in mesenchymal cells in vitro is dependent on the stage of chondrogenesis, and its expression in vivo demarcates chondrocytes that are not destined to be consumed by endochondral ossification. Functionally, Erg expression causes downregulation of Col2a1 and Col10a1 expression and this effect is potentially mediated by Osr2, which is a known regulator of chondrocyte differentiation. The identification of Ube2b as a putative downstream target of Erg-010 suggests that it may contribute to the regulation of the ubiquitination pathway and thereby BMP2 signaling, which is essential for normal knee joint development. RNA from overexpression experiments was extracted as described above. Total RNA quality was confirmed using a Bioanalyzer 2100 (Agilent). Labelled targets were generated from total RNA and hybridized to GeneChip Mouse Genome 430 2.0 arrays (Affymatrix) (Genomics Centre, University of Manchester). The raw fluorescence intensity values were normalized using a Robust Multi-array Average approach using dChip (V2005)
2015-01-20 | E-GEOD-65077 | biostudies-arrayexpress
Project description:Injuries to the anterior cruciate ligament (ACL) often result in post-traumatic osteoarthritis (PTOA). PTOA accounts for ~12% of all osteoarthritis (OA) cases, yet the mechanisms contributing to OA after joint injury are not well understood. To better understand the molecular mechanisms behind PTOA development following ACL injury, we profiled ACL injury-induced gene expression changes in knee joints of three mouse strains with varying susceptibility to PTOA: STR/ort (highly susceptible), C57BL/6 (moderately susceptible) and super-healer MRL/MpJ (not susceptible) and identified genes differentially expressed between these strains at 0-day [before injury], 1-day, 1-week, and 2-weeks post-injury. This study highlights many new potential therapeutic targets and OA biomarkers.
2018-11-28 | GSE112641 | GEO
Project description:Post-traumatic Osteoarthritis (PTOA) occurs in about half of individuals who sustained articular injuries including tibial plateau fracture, meniscus tear, or an anterior cruciate ligament (ACL) rupture. We utilize a noninvasive tibial compression injury (TCI) model that can closely replicate the anterior cruciate ligament rupture in patients, which reliably initiates PTOA development. In other studies we utilize single-cell RNA sequencing to temporally explore differences in immune cell infiltration following injury. Although extreme care is taken during immune cell isolation to prevent contamination from bone marrow, we also wanted to rule out the possibility of contamination from bone marrow immune cells in our knee joint samples. Therefore, we proceeded to compare the neutrophil populations from uninjured joint (joint) to bone marrow (marrow) to identify the similarities and differences between these populations.
2025-07-05 | GSE236844 | GEO
Project description:Limb development begins with limb buds that develop into long appendicular bones separated by joint-forming structures called interzones. Mesenchymal progenitor cells of the interzone differentiate into cartilaginous and fibrous tissues of the synovial joint, including articular cartilage, menisci, and ligaments. Platelet-derived growth factor receptor-α (PDGFRα) is expressed by mesenchymal cells of the limb bud, but it is not known to have a role in limb or joint development. By analyzing PDGFRα expression in single-cell RNA sequencing data, immunofluorescence, and lineage tracing, we observed dynamic PDGFRα expression in the mouse limb bud, interzone, and perichondral mesenchyme. To investigate PDGFRα function, we use Prrx1-Cre to cause mouse limb bud mesenchyme to express mutant PDGFRα with a kinase domain point mutation (D842V) that increases receptor signaling. Overall limb development was unaffected. However, the hind limbs were immobile with knee joints fused by cartilage and lacking ligaments and menisci. The mutant perichondrium exhibited ectopic cartilage matrix and the enthesis of the patellar tendon was enlarged. The interzone marker Gdf5 was initially expressed at E12.5 but was downregulated at E13.5 and thereafter, suggesting a defect in maintenance of the interzone. Spatial transcriptomics of the mutant joint identified co-expression of genes for both cartilage (Sox9, Col2a1) and fibrotic tissue (Postn, Col1a1, Col1a2), suggesting fibrocartilage. These data suggest that elevated PDGFRα signaling corrupts joint tissue differentiation by downregulating Gdf5 and redirecting interzone progenitors into a fibrocartilage fate. These results highlight the need to balance chondrogenic and fibrogenic cell fates during joint development, with tight regulation of PDGFRα signaling as a necessity for the development of the mouse knee joint.
2025-04-01 | GSE289874 | GEO