Project description:Pax1 and Pax9 play redundant, synergistic functions in the patterning and differentiation of the sclerotomal cells that give rise to the vertebral bodies and intervertebral discs (IVD) of the axial skeleton. Gene expression profiling of an enriched population of Pax1/Pax9-expressing cells of the embryonic IVD revealed that Pax1 and Pax9 regulate cell proliferation, cartilage development, collagen fibrillogenesis and other processes vital in early IVD morphogenesis. Twenty-nine of the Pax1/Pax9 targets are also associated with axial skeletal defects that phenocopy Pax1/Pax9-deficient mice. Pax1 likely auto-regulates itself and is up-regulated in the absence of Pax9, clarifying how it compensates for the loss of Pax9, while Pax9 is unaffected by the loss of Pax1. Pax1 and Pax9 positively regulate several of the cartilage development genes known to be regulated by the “Sox trio” (Sox5/Sox6/Sox9).
Project description:Background Adolescent idiopathic scoliosis (AIS) is a complex spinal deformity characterized by three-dimensional curvature of the spine with an unknown etiology. Previous genome-wide association studies have identified a single-nucleotide polymorphism (rs6137473) located downstream of PAX1, which is significantly associated with female AIS risk. Methods To investigate the role of this region in spinal development and AIS pathogenesis, we generated a mouse model with deletion of a nearby conserved sex-associated region (Pax1-SARΔ). Spines were examined by both micro-CT and histology. Gene expression analysis (by RNA-sequencing and quantitative PCR) was carried out on E12.5 and E18.5 developing spines. Glycosaminoglycan (GAG) content was also measured by high-performance liquid chromatography. Results Micro-CT analysis revealed increased vertebral rotation at T4 in female Pax1-SARΔ mice at 4 months and at T9 in male Pax1-SARΔ mice at 6 months, along with kyphotic and lordotic sagittal curvatures. Histological examination revealed significant intervertebral disc degeneration, with the most severe changes observed in the female Pax1-SARΔ mice. GAG analysis found decreased chondroitin sulfate and dermatan sulfate content in male and female Pax1-SARΔ mice. Gene expression analysis at E12.5 showed upregulation of Pax1, Stat3, Ar, Foxa2, and Nkx2.2, while RNA-sequencing at E18.5 revealed sex-dependent changes in gene expression related to extracellular matrix components, immune and inflammatory responses, and scoliosis. Conclusion: These findings highlight the pivotal role of the Pax1 sex-associated genomic region in the development and maintenance of functional cartilage, extracellular matrix integrity, and intervertebral disc health, offering insights into the mechanisms underlying spinal degeneration and instability in AIS.
Project description:Recapitulation of developmental signals represents a promising strategy for treating intervertebral disc degeneration. During development, embryonic notochord-derived cells (NDCs) are the direct progenitors of cells that populate the adult nucleus pulposus (NP) and are an important source of secreted signaling molecules. The objective of this study was to define global gene expression profiles of NDCs at key stages of embryonic disc formation. NDCs were isolated from Shh-cre;ROSA:YFP mice at embryonic day 12.5 and postnatal day 0, representing opposite ends of the notochord to NP transformation. Differences in global mRNA abundance across this developmental window were established using RNA-Seq. Principal component analysis revealed clustering of gene expression at each developmental stage with more than 5000 genes significantly differentially expressed between E12.5 and P0. This study represents the first transcriptome-wide analysis of embryonic NDCs. Results suggest signaling and biosynthesis of NDCs change dramatically as a function of developmental stage.
Project description:This SuperSeries is composed of the following subset Series: GSE18647: Gene expression in embryonic intervertebral disc and vertebrae. GSE18648: TGF-beta and BMP mediated gene expression in cultured sclerotome. Refer to individual Series
Project description:Lactate accumulation is a hallmark and contributing factor of intervertebral disc degeneration (IVDD). Lactate accumulation facilitates protein lactylation, while the role and mechanism of protein lactylation in IVDD remain unclear. In this study, we performed sequencing of the lactylation sites of whole protein in nucleus pulposus tissues of 3 normal and 3 acupuncture induced intervertebral disc degeneration rats to explore the function of different lactylation sites and their effects on intervertebral disc degeneration.
Project description:Failure of intervertebral disc components, e.g. the nucleus pulposus causes intervertebral disc disease and associated low-back pain. Despite the high prevalence of disc disease, the changes in intervertebral disc cells and their regenerative potential with ageing and degeneration are not fully elucidated. Understanding the cell lineage, cell differentiation and maintenance of nucleus pulposus may have therapeutic application for the regeneration of degenerative disc, with significant impact for healthy ageing. Here we found that TAGLN expressing cells are present in human healthy nucleus pulposus, but diminish in degenerative disc. By lineage analyses in mice, we found cells in the nucleus pulposus are derived from a peripherally located population of notochord-derived Tagln expressing cells (PeriNP cells). The PeriNP cells are proliferative and can differentiate into the inner part of the nucleus pulposus. The Tagln+ cells and descendants diminish during aging and puncture induced disc degeneration. The maintenance and differentiation of PeriNP cells is partially regulated by Smad4 dependent signaling. Removal of Smad4 by nucleus pulposus specific Cre (Foxa2mNE-Cre), results in decreased Tagln+ cells and abnormal disc morphology, leading to disc degeneration. Our findings propose that the PeriNP Tagln expressing cells are a pool of notochord-derived progenitors that are important for maintenance of the nucleus pulposus and provide insights for regenerative therapy against intervertebral disc degeneration.
Project description:Herniation of the intervertebral disc (IVDH) is the most common cause of neurological and intervertebral disc degeneration-related diseases. Since the disc starts to degenerate before it can be observed by currently available diagnostic methods, there is an urgent need for novel diagnostic approaches. To identify molecular networks and pathways which may play important roles in intervertebral disc herniation, as well as to reveal the potential features which could be useful for monitoring disease progression and prognosis, multi-omics profiling including high-resolution LC-MS-based metabolomics and proteomics was performed. Furthermore, multi-omics data were integrated to decipher a complex interaction between individual omic layers leading to improved prediction model. Together with metabolic pathways related to amino acids and lipid metabolism, and coagulation cascades, our integromics prediction model identified the key features in IVDH, namely the proteins FSTL1, SCG5, NUCB1 and CRSP2 and the metabolites N-acetyl-D-glucosamine and adenine, involved in neuropathic pain, myelination, neurotransmission and inflammatory response, respectively. Their clinical application is to be further investigated. The utilization of novel integrative interdisciplinary strategy may provide opportunities to apply the innovative diagnostic and monitoring methods for degenerative spinal disorders.