Project description:To examine the unbiased global gene expression of over-expression of Prg4 in superficial zone articular chondrocytes in mice. This approach allows us to define novel signaling changes caused by the over-expression of Prg4 in superficial zone articular chondrocytes Total RNA was isolated from superficial zone chondrocytes in P1 articular cartilage in hind limbs (n=3) by laser capture microdissection. Same tissue from wild type mice served as control
Project description:We used laser capture microdissection to isolate different zones of the articular cartilage from proximal tibiae of 1-week old mice, and used microarray to analyze global gene expression. Bioinformatic analysis corroborated previously known signaling pathways, such as Wnt and Bmp signaling, and implicated novel pathways, such as ephrin and integrin signaling, for spatially associated articular chondrocyte differentiation and proliferation. In addition, comparison of the spatial regulation of articular and growth plate cartilage revealed unexpected similarities between the superficial zone of the articular cartilage and the hypertrophic zone of the growth plate. Collecte five biological replications in three superficial, mid zone and deep zones of Articular Cartilage Assessed by Laser Captured Microdissection and Microarray(Superficial Zone vs Mid Zone vs Deep Zone)
Project description:Articular and growth plate cartilage have comparable structures consisting of three distinct layers of chondrocytes, suggesting similar differentiation programs and therefore similar gene expression profiles. To address this hypothesis and to explore transcriptional changes that occur during the onset of articular and growth plate cartilage divergence, we used microdissection of 10-day-old rat proximal tibial epiphyses, microarray analysis, and bioinformatics to compare gene expression profiles in individual layers of articular and growth plate cartilage. We found that many genes that were spatially upregulated in intermediate/deep zone of articular cartilage were also spatially upregulated in resting zone of growth plate cartilage (overlap greater than expected by chance, P < 0.001). Interestingly, superficial zone of articular cartilage showed an expression profile with similarities to both proliferative and hypertrophic zones of growth plate cartilage (P < 0.001 each). Additionally, significant numbers of known proliferative zone markers (3 out of 6) and hypertrophic zone markers (27 out of 126) were spatially upregulated in superficial zone compared to intermediate/deep zone (more than expected by chance, P < 0.001 each). In conclusion, we provide evidence that intermediate/deep zone of articular cartilage has a gene expression profile more similar to resting zone of growth plate cartilage, whereas superficial zone has a gene expression profile more similar to proliferative and hypertrophic zones.
Project description:Articular and growth plate cartilage have comparable structures consisting of three distinct layers of chondrocytes, suggesting similar differentiation programs and therefore similar gene expression profiles. To address this hypothesis and to explore transcriptional changes that occur during the onset of articular and growth plate cartilage divergence, we used microdissection of 10-day-old rat proximal tibial epiphyses, microarray analysis, and bioinformatics to compare gene expression profiles in individual layers of articular and growth plate cartilage. We found that many genes that were spatially upregulated in intermediate/deep zone of articular cartilage were also spatially upregulated in resting zone of growth plate cartilage (overlap greater than expected by chance, P < 0.001). Interestingly, superficial zone of articular cartilage showed an expression profile with similarities to both proliferative and hypertrophic zones of growth plate cartilage (P < 0.001 each). Additionally, significant numbers of known proliferative zone markers (3 out of 6) and hypertrophic zone markers (27 out of 126) were spatially upregulated in superficial zone compared to intermediate/deep zone (more than expected by chance, P < 0.001 each). In conclusion, we provide evidence that intermediate/deep zone of articular cartilage has a gene expression profile more similar to resting zone of growth plate cartilage, whereas superficial zone has a gene expression profile more similar to proliferative and hypertrophic zones. 10-day-old rat proximal tibial epiphyses were manually microdissected into articular cartilage superficial (SZ) and intermediate/deep (IDZ) zones and growth plate cartilage resting zone (RZ) for total RNA extraction and hybridization on Affymetrix microarrays. We used 10-day-old animals because, at this age, the secondary ossification center has recently begun to form and divides the epiphysis into articular cartilage distally and growth plate cartilage more centrally. The 4 SZ samples were taken from animals 5-8, respectively, whereas the 4 IDZ and 4 RZ samples were each taken from animals 1-2, 3-4, 5-6, and 7-8, respectively.
Project description:We used laser capture microdissection to isolate different zones of the articular cartilage from proximal tibiae of 1-week old mice, and used microarray to analyze global gene expression. Bioinformatic analysis corroborated previously known signaling pathways, such as Wnt and Bmp signaling, and implicated novel pathways, such as ephrin and integrin signaling, for spatially associated articular chondrocyte differentiation and proliferation. In addition, comparison of the spatial regulation of articular and growth plate cartilage revealed unexpected similarities between the superficial zone of the articular cartilage and the hypertrophic zone of the growth plate.
Project description:To examine the unbiased global gene expression of over-expression of Prg4 in superficial zone articular chondrocytes in mice. This approach allows us to define novel signaling changes caused by the over-expression of Prg4 in superficial zone articular chondrocytes
Project description:The characterization of knee articular cartilage changes with different zones -- articular surface, (AS), superficial zone (SZ), middle zone (MZ), and deep zone (DZ) -- based on the organization of the tissue and the alignment degree of collagen fibers. To comprehensively explore the spatial landscape of chondrocytes on human knee articular cartilage, we carried out the laser capture microdissection (LCM) coupled with full-length mRNA sequencing.
Project description:To identify genes that maintain the homeostasis of the articular cartilage, we compared gene expression profiles of adult articular cartilage chondrocytes with that of growth plate cartilage chondrocytes in adult (10-week-old) Sprague Dawley (SD) rats. Furthermore, to identify genes that have a potency to regenerate the articular cartilage, we compared gene expression profiles of superficial layer chondrocytes of infant epiphyseal cartilage which form articular cartilage with that of the deep layer chondrocytes which form growth plate cartilage in infant (6-day-old) SD rats.
Project description:While prior work has established that articular cartilage arises from Prg4-expressing perichondrial cells, it is not clear how this process is specifically restricted to the perichondrium of synovial joints. We document that the transcription factor Creb5 is necessary to initiate the expression of signaling molecules that both direct the formation of synovial joints and guide perichondrial tissue to form articular cartilage instead of bone. Creb5 promotes the generation of articular chondrocytes from perichondrial precursors in part by inducing expression of Wif1, which blocks a Wnt5a autoregulatory loop in the perichondrium. Postnatal deletion of Creb5 in the articular cartilage leads to loss of both flat superficial zone articular chondrocytes coupled with a loss of both Prg4 and Wif1 expression; and a non-cell autonomous up-regulation of Ctgf. Our findings indicate that Creb5 promotes both joint formation and the subsequent development of articular chondrocytes by disrupting a Wnt5a positive-feedback loop in the perichondrium.