The goal of the competitive renewal is to test the hypothesis that in the hypoxic niche of the intervertebral disc, notch signaling is required for maintenance of proliferation and differentiation of cell populations. The objective of the first Specific Aim is to characterize the expression of notch and notch ligands and to investigate the importance of notch signaling in proliferation and differentiation of disc cells;to assess notch and notch ligand expression in tissue isolated from patients with degenerative disc disease. Using loss and gain of function studies we will determine the importance of the notch system in terms of cell proliferation and acquisition of the mature phenotype. By evaluating the localization of notch receptors and ligands we will gain insight into the interaction between different cell types within the disc. The goal of the second Specific Aim is to ascertain if in the hypoxic microenvironment notch and HIF signaling co-regulate expression of selective notch receptors, ligands and notch target genes in disc cells;in addition, we will determine if notch target genes Hey1 and Hey2 influence HIF function. In parallel, the interaction between notch and HIF will be assessed to evaluate the involvement of notch-ICD in the regulation of HIF-1 target genes. A final goal is to examine proliferative cells isolated from degenerate human discs for the expression and activities of notch signaling components. In the third Aim we will use a notochord specific knockout mice to investigate the importance of notch signaling in governing cell proliferation, survival and function during disc development and to delineate the role of notch in modulating HIF-1 function in the disc. Since we will also delete HIF-1, these studies will reveal the importance of this gene in regulating notch activity. The goal of the last Specific Aim is to develop an animal model to learn if inactivation of notch activity promotes a loss of cellularity, a decrease in number of differentiated cells and eventual degeneration of the intervertebral disc. We will inject rabbit intervertebral discs with lentivirus encoding psen1/psen2-SiRNA to suppress expression of endogenous notch activity. We will measure the activities of components of the notch signaling system, HIF function, the activities and numbers of proliferative cells and assess the degenerative status of the disc itself. These studies will validate and further extend the investigations described above, and provide new information on the critical role of notch signaling in terms of proliferation, survival, and differentiation of disc cells. Results of the investigation should provide a new understanding of how cell proliferation is regulated in the disc and provide a strategy for future use of pharmacological agents, and molecular genetic or tissue engineering approaches for effecting tissue repair utilizing endogenous disc cells.
Lower back pain is closely linked to degenerative disc disease, a problem that afflicts most of the adult population. One approach to enhancing disc health is to promote the activity of stem cells that are resident in the disc. The goal of the proposal is to understand the mechanism that controls the fate and function of these progenitor cells in both the normal and diseased intervertebral disc.
|Binch, Abbie L A; Shapiro, Irving M; Risbud, Makarand V (2016) Syndecan-4 in intervertebral disc and cartilage: Saint or synner? Matrix Biol 52-54:355-362|
|Schoepflin, Zachary R; Shapiro, Irving M; Risbud, Makarand V (2016) Class I and IIa HDACs Mediate HIF-1? Stability Through PHD2-Dependent Mechanism, While HDAC6, a Class IIb Member, Promotes HIF-1? Transcriptional Activity in Nucleus Pulposus Cells of the Intervertebral Disc. J Bone Miner Res 31:1287-99|
|Suyama, Kaori; Silagi, Elizabeth S; Choi, Hyowon et al. (2016) Circadian factors BMAL1 and ROR? control HIF-1? transcriptional activity in nucleus pulposus cells: implications in maintenance of intervertebral disc health. Oncotarget 7:23056-71|
|Tian, Ye; Yuan, Wen; Li, Jun et al. (2016) TGF? regulates Galectin-3 expression through canonical Smad3 signaling pathway in nucleus pulposus cells: implications in intervertebral disc degeneration. Matrix Biol 50:39-52|
|Choi, Hyowon; Johnson, Zariel I; Risbud, Makarand V (2015) Understanding nucleus pulposus cell phenotype: a prerequisite for stem cell based therapies to treat intervertebral disc degeneration. Curr Stem Cell Res Ther 10:307-16|
|Li, Jun; Yuan, Wen; Jiang, Shuai et al. (2015) Prolyl-4-hydroxylase domain protein 2 controls NF-?B/p65 transactivation and enhances the catabolic effects of inflammatory cytokines on cells of the nucleus pulposus. J Biol Chem 290:7195-207|
|Ye, Wei; Zhou, Jie; Markova, Dessislava Z et al. (2015) Xylosyltransferase-1 expression is refractory to inhibition by the inflammatory cytokines tumor necrosis factor ? and IL-1? in nucleus pulposus cells: novel regulation by AP-1, Sp1, and Sp3. Am J Pathol 185:485-95|
|Johnson, Z I; Schoepflin, Z R; Choi, H et al. (2015) Disc in flames: Roles of TNF-? and IL-1? in intervertebral disc degeneration. Eur Cell Mater 30:104-16; discussion 116-7|
|Shapiro, Irving M; Landis, William J; Risbud, Makarand V (2015) Matrix vesicles: Are they anchored exosomes? Bone 79:29-36|
|Johnson, Zariel I; Gogate, Shilpa S; Day, Rebecca et al. (2015) Aquaporin 1 and 5 expression decreases during human intervertebral disc degeneration: Novel HIF-1-mediated regulation of aquaporins in NP cells. Oncotarget 6:11945-58|
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