Project description:This study sought to elucidate the transcriptomic changes in the murine nucleus pulposus (NP) with age. These findings will contribute to the understanding of murine intervertebral disc (IVD) aging and degeneration.
Project description:Mice lacking equilibrative nucleoside transporter 1 demonstrate progressive calcification of spinal tissues including the annulus fibrosus (AF) of the intervertebral disc (IVD). To identify cellular pathways altered by loss of ENT1, we conducted microarray analysis of AF tissue from wild-type (WT) and ENT1-null mice before calcification (2 months) and associated with calcification (6 months).
Project description:IVDs are composed of heterogeneous cell groups, a further understanding of marker genes and cell phenotypes of healthy mature IVD cells is essential.
Project description:The circadian clock in mammals temporally coordinates physiological and behavioural processes to anticipate daily rhythmic changes in their environment. Chronic disruption to circadian rhythms (e.g., through ageing or shift work) is thought to contribute to a multitude of diseases, including degeneration of the musculoskeletal system. The intervertebral disc (IVD) in the spine contains circadian clocks which control ~6% of the transcriptome in a rhythmic manner, including key genes involved in extracellular matrix (ECM) homeostasis. However, it remains largely unknown to what extent the local IVD molecular clock is required to drive rhythmic gene transcription and IVD physiology. In this work, we identified profound age-related changes of ECM microarchitecture and an endochondral ossification-like phenotype in the annulus fibrosus (AF) region of the IVD in the Col2a1-Bmal1 knockout mice. Reported here is the circadian time series RNA-Seq of the whole IVD in Bmal1 knockout mice.
Project description:The intervertebral disc (IVD) is a spinal joint that accumulates damage with age but has limited tissue repair capabilities. IVD damage progresses into degeneration, and IVD degeneration is a leading cause of lower back pain. There are no effective therapies to treat IVD degeneration, but understanding the cell populations that change and respond to injury will uncover targets to restore IVD function. Mesenchymal stem cells (MSCs) are cells within the IVD that can potentially replenish the cells lost after IVD damage. To identify the cell populations of the IVD and how they change with injury, we performed single cell RNA sequencing of IVD tissue 7 days post injury and analyzed the differences in gene regulation. We identified diverse cells populations such as IVD specific tissues, immune cells, vascular cells, and MSCs. We discovered the presence of Saa2 and Grem1 expressing MSCs that become less stem cell-like and express higher levels of IVD gene markers after injury. We also determined that Saa2 and Grem1 have slightly different expression patterns in IVD tissues, and this expression becomes reduced after injury. These MSCs could be used in future stem cell therapies to prevent IVD degeneration.
Project description:Intervertebral disc (IVD) degeneration is often the cause of low back pain. Degeneration occurs with age and is accompanied by extracellular matrix (ECM) depletion, culminating in nucleus pulpous (NP) extrusion and IVD destruction. The changes that occur in the disc with age have been under investigation. However, a thorough study of ECM remodelling is needed, to better understand IVD development and age-associated degeneration. As so, iTRAQ LC-MS/MS analysis of foetus, young and old bovine NPs, was used to define the NP matrisome. The enrichment of Collagen XII and XIV in foetus, Fibronectin and Prolargin in elder samples and Collagen XI in young ones was independently validated. This study provides the first matrisome database of healthy discs during development and ageing, which is key to determine the pathways and processes that maintain disc homeostasis. The factors identified may help to explain age-associated IVD degeneration or constitute putative effectors for disc regeneration.
Project description:Intervertebral disc (IVD) is often the cause of low back pain. Degeneration occurs with age and is accompanied by extracellular matrix (ECM) depletion, culminating in nucleus pulpous (NP) extrusion and IVD destruction. Although the changes that occur with ageing in the IVD have been under study, not much attention has been given to ECM remodelling during normal development. Therefore, a thorough study of ECM composition and a comprehensive view on how this microenvironment is affected in normal ageing conditions is needed, to better understand the processes involved in IVD development and in age-associated degeneration. We have compared the NP matrisome of bovine IVDs from foetus, young and old animals by quantitative iTRAQ LC-MS/MS. Protein expression levels of the most interesting candidates were validated by Western Blot analysis. In total, 161 bovine proteins were identified. Of these, 77 molecules were common to the three different age groups, of which 36 defined the NP matrisome. Differential expression levels obtained for Collagen Type XI, XII, XIV, Fibronectin and Prolargin were independently confirmed. Herein, we demonstrate a shift in NP matrisome signatures that occurs in healthy bovine IVDs with development and ageing. Thus, this study provides insight into factors that may explain age-associated IVD degeneration, and which are putative targets for therapy. It also highlights key molecules, characteristic of early developmental stages, which constitute potential effectors in IVD regeneration.