Suppression of sost/sclerostin and dickkopf-1 promote intervertebral disc structure in mice

Intervertebral disc (IVD) degeneration is a leading cause of low back pain and characterized by accelerated extracellular matrix breakdown and IVD height loss but there is no approved pharmacological therapeutic. Deletion of Wnt signaling receptor Lrp5 induces IVD degeneration and suggests that Wnt signaling in the IVD may be responsive to inhibition of Wnt signaling inhibitors sost(gene)/sclerostin(protein) or dickkopf-1 (dkk1). Anti-sclerostin antibody (Scl-Ab) is an FDA-approved bone therapeutic that activates Wnt signaling. We (1) determined if pharmacological neutralization of sclerostin, dkk1 or their combination stimulate Wnt signaling and promote IVD structure and (2) determined the extent of the response of the IVD to global, persistent deletion of sost. Nine-week-old C57Bl/6J female mice (n=6-7/grp) were subcutaneously injected 2x/wk for 5.5 wk with Scl-Ab (25 mg/kg), Dkk1-Ab (25 mg/kg), 3:1 Scl-Ab/Dkk1-Ab (18.75:6.25 mg/kg) or vehicle (Veh). Separately, IVD of sost KO and WT (wildtype) mice (n=8, grp) were harvested at 16 weeks of age. First, compared to vehicle, Scl-Ab, Dkk1-Ab and 3:1 Scl-Ab/Dkk1-Ab similarly increased lumbar IVD height and β-catenin gene expression. Despite these similarities, Scl-Ab decreased cellular stress-related heat shock protein gene expressions while neither Dkk1-Ab nor Scl-Ab/Dkk1-Ab altered the same. Genetically and compared to WT, sost KO increased MRI-determined hydration and proteoglycan staining in the IVD. Notably, persistent deletion of sost was compensated by upregulation of Dkk1, which consequently reduced the cellular nuclear fraction for Wnt signaling transcription factor β-catenin in whole IVD. Lastly, RNA-sequencing pathway analysis confirmed the suppression of Wnt signaling and cellular stress pathways. Together, suppression of sost/sclerostin or dkk1 each promote IVD structure by stimulating Wnt signaling, but sclerostin and dkk1 may differentially regulate cellular stress pathways. Ultimately, postmenopausal women prescribed Scl-Ab to prevent vertebral fracture may also benefit from a restoration of IVD height and health.

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LRP5-deficiency in OsxCreERT2 mice models intervertebral disc degeneration by aging and compression

10.1101/720656 ◽

2019 ◽

Author(s):

Matthew J. Silva ◽

Nilsson Holguin

Keyword(s):

Transcription Factor ◽

Intervertebral Disc ◽

Wnt Signaling ◽

Cell Fate ◽

Biomechanical Properties ◽

Nucleus Pulposus Cells ◽

Hypertrophic Chondrocyte ◽

Age Related ◽

Ivd Degeneration

ABSTRACTOsterix is a critical transcription factor of mesenchymal stem cell fate, where its loss or loss of WNT signaling diverts differentiation to a chondrocytic lineage. Intervertebral disc (IVD) degeneration activates differentiation of prehypertrophic chondrocyte-like cells and inactivates WNT signaling, but its interacting role with osterix is unclear. First, compared to young-adult (5mo), mechanical compression of old (18mo) IVD induced greater IVD degeneration. Aging (5 vs 12mo) and/or compression reduced the transcription of osterix and notochordal marker T by 40-75%. Compression elevated transcription of hypertrophic chondrocyte marker MMP13 and pre-osterix transcription factor RUNX2, but less so in 12mo IVD. Next, using an Ai9/td reporter and immunohistochemistry, annulus fibrosus and nucleus pulposus cells of 5mo IVD expressed osterix, but aging and compression reduced its expression. Lastly, in vivo LRP5-deficiency in osterix-expressing cells degenerated the IVD, inactivated WNT signaling, reduced the biomechanical properties by 45-70%, and reduced transcription of osterix, notochordal markers and chondrocytic markers by 60-80%. Overall, these data indicate that age-related inactivation of WNT signaling in osterix-expressing cells may limit regeneration by depleting progenitors and attenuating the expansion of chondrocyte-like cells.

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The role of sclerostin and dickkopf-1 in oral tissues – A review from the perspective of the dental disciplines

F1000Research ◽

10.12688/f1000research.17801.1 ◽

2019 ◽

Vol 8 ◽

pp. 128

Author(s):

Mohammad Samiei ◽

Klara Janjić ◽

Barbara Cvikl ◽

Andreas Moritz ◽

Hermann Agis

Keyword(s):

Wnt Signaling ◽

Oral Surgery ◽

Current Knowledge ◽

Therapeutic Strategies ◽

Tissue Formation ◽

Hard Tissue ◽

Signaling Inhibitors ◽

The Impact ◽

Dickkopf 1

Wnt signaling is of high relevance in the development, homeostasis, and regeneration of oral tissues. Therefore, Wnt signaling is considered to be a potential target for therapeutic strategies. The action of Wnt is tightly controlled by the inhibitors sclerostin (SOST) and Dickkopf (DKK)-1. Given the impact of SOST and DKK-1 in hard tissue formation, related diseases and healing, it is of high relevance to understand their role in oral tissues. The clinical relevance of this knowledge is further underlined by systemic and local approaches which are currently in development for treating a variety of diseases such as osteoporosis and inflammatory hard tissue resorption. In this narrative review, we summarize the current knowledge and understanding on the Wnt signaling inhibitors SOST and DKK-1, and their role in physiology, pathology, and regeneration in oral tissues. We present this role from the perspective of the different specialties in dentistry, including endodontics, orthodontics, periodontics, and oral surgery.

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Influence of Angiopoietin Treatment with Hypoxia and Normoxia on Human Intervertebral Disc Progenitor Cell’s Proliferation, Metabolic Activity, and Phenotype

Applied Sciences ◽

10.3390/app11157144 ◽

2021 ◽

Vol 11 (15) ◽

pp. 7144

Author(s):

Muriel C. Bischof ◽

Sonja Häckel ◽

Andrea Oberli ◽

Andreas S. Croft ◽

Katharina A. C. Oswald ◽

...

Keyword(s):

Gene Expression ◽

Intervertebral Disc ◽

Metabolic Activity ◽

Cell Metabolism ◽

Trauma Patients ◽

Low Back ◽

Relative Gene Expression ◽

Progenitor Cell Population ◽

Ivd Degeneration ◽

Relative Gene

Increasing evidence implicates intervertebral disc (IVD) degeneration as a major contributor to low back pain. In addition to a series of pathogenic processes, degenerated IVDs become vascularized in contrast to healthy IVDs. In this context, angiopoietin (Ang) plays a crucial role and is involved in cytokine recruitment, and anabolic and catabolic reactions within the extracellular matrix (ECM). Over the last decade, a progenitor cell population has been described in the nucleus pulposus (NP) of the IVD to be positive for the Tie2 marker (also known as Ang-1 receptor). In this study, we investigated the influence of Ang-1 and Ang-2 on human NP cell (Tie2+, Tie2- or mixed) populations isolated from trauma patients during 7 days in normoxia (21% O2) or hypoxia (≤ 5% O2). At the end of the process, the proliferation and metabolic activity of the NP cells were analyzed. Additionally, the relative gene expression of NP-related markers was evaluated. NP cells showed a higher proliferation depending on the Ang treatment. Moreover, the study revealed higher NP cell metabolism when cultured in hypoxia. Additionally, the relative gene expression followed, with an increase linked to the oxygen level and Ang concentration. Our study comparing different NP cell populations may be the start of new approaches for the treatment of IVD degeneration.

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Catalytic Asymmetric Synthesis of Mixed 3,3′-Bisindoles and Their Evaluation as Wnt Signaling Inhibitors

Angewandte Chemie ◽

10.1002/ange.201208918 ◽

2013 ◽

Vol 125 (9) ◽

pp. 2546-2550 ◽

Cited By ~ 18

Author(s):

Takayoshi Arai ◽

Yushi Yamamoto ◽

Atsuko Awata ◽

Kentaro Kamiya ◽

Masami Ishibashi ◽

...

Keyword(s):

Wnt Signaling ◽

Asymmetric Synthesis ◽

Catalytic Asymmetric Synthesis ◽

Signaling Inhibitors ◽

Catalytic Asymmetric

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The Myth of Fibroid Degeneration in the Canine Intervertebral Disc: A Histopathological Comparison of Intervertebral Disc Degeneration in Chondrodystrophic and Nonchondrodystrophic Dogs

Veterinary Pathology ◽

10.1177/0300985817726834 ◽

2017 ◽

Vol 54 (6) ◽

pp. 945-952 ◽

Cited By ~ 10

Author(s):

Tove Hansen ◽

Lucas A. Smolders ◽

Marianna A. Tryfonidou ◽

Björn P. Meij ◽

Johannes C. M. Vernooij ◽

...

Keyword(s):

Intervertebral Disc ◽

Nucleus Pulposus ◽

Disc Degeneration ◽

Intervertebral Disc Degeneration ◽

Histopathological Changes ◽

Seminal Work ◽

Notochordal Cells ◽

Tissue Changes ◽

Chondroid Metaplasia ◽

Ivd Degeneration

Since the seminal work by Hans-Jörgen Hansen in 1952, it has been assumed that intervertebral disc (IVD) degeneration in chondrodystrophic (CD) dogs involves chondroid metaplasia of the nucleus pulposus, whereas in nonchondrodystrophic (NCD) dogs, fibrous metaplasia occurs. However, more recent studies suggest that IVD degeneration in NCD and CD dogs is more similar than originally thought. Therefore, the aim of this study was to compare the histopathology of IVD degeneration in CD and NCD dogs. IVDs with various grades of degeneration (Thompson grade I–III, n = 7 per grade) from both CD and NCD dogs were used (14 CD and 18 NCD dogs, 42 IVDs in total). Sections were scored according to a histological scoring scheme for canine IVD degeneration, including evaluation of the presence of fibrocyte-like cells in the nucleus pulposus. In CD dogs, the macroscopically non-degenerated nucleus pulposus contained mainly chondrocyte-like cells, whereas the non-degenerated nucleus pulposus of NCD dogs mainly contained notochordal cells. The histopathological changes in degenerated discs were similar in CD and NCD dogs and resembled chondroid metaplasia. Fibrocytes were not seen in the nucleus pulposus, indicating that fibrous degeneration of the IVD was not present in any of the evaluated grades of degeneration. In conclusion, intervertebral disc degeneration was characterized by chondroid metaplasia of the nucleus pulposus in both NCD and CD dogs. These results revoke the generally accepted concept that NCD and CD dogs suffer from a different type of IVD degeneration, in veterinary literature often referred to as chondroid or fibroid degeneration, and we suggest that chondroid metaplasia should be used to describe the tissue changes in the IVD in both breed types.

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Compression Loading Induced Cellular Stress Response of Intervertebral Disc Cells in Organ Culture

Global Spine Journal ◽

10.1055/s-0036-1582604 ◽

2016 ◽

Vol 6 (1_suppl) ◽

pp. s-0036-1582604-s-0036-1582604

Author(s):

Wai Hon Chooi ◽

Samantha C. W. Chan ◽

Benjamin Gantenbein ◽

Barbara P. Chan

Keyword(s):

Stress Response ◽

Intervertebral Disc ◽

Organ Culture ◽

Cellular Stress ◽

Cellular Stress Response ◽

Compression Loading ◽

Disc Cells

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A monoclonal antibody against the Wnt signaling inhibitor dickkopf-1 inhibits osteosarcoma metastasis in a preclinical model

Oncotarget ◽

10.18632/oncotarget.8522 ◽

2016 ◽

Vol 7 (16) ◽

pp. 21114-21123 ◽

Cited By ~ 34

Author(s):

Seth D. Goldstein ◽

Matteo Trucco ◽

Wendy Bautista Guzman ◽

Masanori Hayashi ◽

David M. Loeb

Keyword(s):

Monoclonal Antibody ◽

Wnt Signaling ◽

Preclinical Model ◽

Dickkopf 1

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Computational Modeling Intervertebral Disc Pathophysiology: A Review

Frontiers in Physiology ◽

10.3389/fphys.2021.750668 ◽

2022 ◽

Vol 12 ◽

Author(s):

Mallory Volz ◽

Shady Elmasry ◽

Alicia R. Jackson ◽

Francesco Travascio

Keyword(s):

Intervertebral Disc ◽

Computational Modeling ◽

Medical Condition ◽

Primary Source ◽

Special Focus ◽

Biochemical Alterations ◽

Wide Range ◽

Mechanical Factors ◽

Ivd Degeneration ◽

Physical Changes

Lower back pain is a medical condition of epidemic proportion, and the degeneration of the intervertebral disc has been identified as a major contributor. The etiology of intervertebral disc (IVD) degeneration is multifactorial, depending on age, cell-mediated molecular degradation processes and genetics, which is accelerated by traumatic or gradual mechanical factors. The complexity of such intertwined biochemical and mechanical processes leading to degeneration makes it difficult to quantitatively identify cause–effect relationships through experiments. Computational modeling of the IVD is a powerful investigative tool since it offers the opportunity to vary, observe and isolate the effects of a wide range of phenomena involved in the degenerative process of discs. This review aims at discussing the main findings of finite element models of IVD pathophysiology with a special focus on the different factors contributing to physical changes typical of degenerative phenomena. Models presented are subdivided into those addressing role of nutritional supply, progressive biochemical alterations stemming from an imbalance between anabolic and catabolic processes, aging and those considering mechanical factors as the primary source that induces morphological change within the disc. Limitations of the current models, as well as opportunities for future computational modeling work are also discussed.

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Reactive Oxygen Species Mediate Low Back Pain by Upregulating Substance P in Intervertebral Disc Degeneration

Oxidative Medicine and Cellular Longevity ◽

10.1155/2021/6681815 ◽

2021 ◽

Vol 2021 ◽

pp. 1-11

Author(s):

Jiancheng Zheng ◽

Jian Zhang ◽

Xingkai Zhang ◽

Zhiping Guo ◽

Wenjian Wu ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Low Back Pain ◽

Back Pain ◽

Substance P ◽

Intervertebral Disc ◽

Reactive Oxygen ◽

Alternative Methods ◽

Low Back ◽

Oxygen Species ◽

Ivd Degeneration

Reactive oxygen species (ROS) are thought to have a strong correlation with a number of intervertebral disc (IVD) diseases. Here, we aimed to determine whether ROS represent an etiology of low back pain (LBP) during IVD degeneration. Thirty degenerated intervertebral disc samples were obtained from patients, and ROS levels were quantified using dihydroethidium (DHE) staining. The results suggested a significant correlation between the ROS level and the severity of LBP. Subsequently, a puncture-induced LBP model was established in rats, and ROS levels significantly increased compared with those in the sham surgery group, accompanied with severe puncture-induced IVD degeneration. In addition, when ROS levels were increased by H2O2 administration or decreased by NAC treatment, the rats showed increased or decreased LBP, respectively. Based on this evidence, we further determined that stimulation with H2O2 in nucleus pulposus cells (NPCs) in vivo or in vitro resulted in upregulation of substance P (SP), a peptide thought to be involved in the synaptic transmission of pain, and that the severity of LBP decreased when SP levels were increased by exogenous SP administration or neutralized via aprepitant treatment in the IVDs of rats. In conclusion, ROS are primary inducers of LBP based on clinical and animal data, and the mechanism involves ROS stimulation of NPCs to secrete SP, which is a critical neurotransmitter peptide, to promote LBP in IVDs. Therefore, reducing the level of ROS with specific drugs and inhibiting SP may be alternative methods to treat LBP in the clinic.

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