Effect of Parathyroid Hormone on MAPK Signaling and Calcification Markers in Human Intervertebral Disk Cells
Notice bibliographique
Résumé
Introduction Back pain is strongly associated with degeneration of the intervertebral disk (IVD), which is associated with ongoing mineral deposition. 1 The presence of calcium deposits and type X collagen (COL X) and the level of the indicators of calcification potential (alkaline phosphatase (ALP), Ca 2 + ions and Pi) were consistently higher in degenerative and scoliotic discs. We also showed that in mesenchymal stem cells (MSCs), parathyroid hormone (PTH 1–34) inhibits the expression of COL X while promoting type II collagen (COL II) expression, thereby preventing endochondral ossification. 2 In this study, we investigated the effect of PTH on expression of COLII, COLX, and ALP in human IVD cells and analyzed the potential mechanisms related to its effect. Materials and Methods Human lumbar IVDs from a donor without spinal pathology were obtained within 24 hours after death. Nucleus pulposus (NP) and annulus fibrosus (AF) tissues from the IVDs were digested and the corresponding NP and AF primary cells were isolated as previously described. 3 These cells were cultured in complete DMEM to 90% confluence. Then the cells were incubated overnight in serum-free medium followed by treatment with 100 nM PTH 30 minutes to 48 hours. Protein expression was analyzed by immunoblotting using specific antibodies to COL I and COL II (Abcam, Cambridge, MA), COL X, and PTH receptor 1 (Sigma Aldrich). Expression and phosphorylation of AKT and MAPKs was assessed by using specific corresponding antibodies (Cell Signaling, Danvers, MA). Alkaline phosphatase activity was measured colorimetrically using the StemTAG kit (Cell Biolabs, San Diego, CA, USA) and Ca 2 + release from cells was measured using calcium assay kit (Cayman Chemical, Ann Arbor, MI, USA). Statistical analyses were done using one-way ANOVA, posthoc tests p < 0.05 was considered significant. Results Effect of PTH on PTH receptor 1 We confirmed the presence of PTH receptor 1 on the AF and NP cells and showed the effect of PTH on the PTH receptor 1 activation by incubating AF and NP cells with 100 nM PTH (1–34). Effect of PTH on collagen expression PTH increased the expression of COL-II significantly in AF cells after 6 hours of incubation and in NP cells COL-II expression increased in a time-dependent and sustained manner from 6 to 48 hours of incubation. Expression of COL-X was not altered by PTH in AF cells, whereas in NP cells it decreased significantly from 6 to 48 hours. Effect of PTH on MAPK signaling PTH causes ERK activation by phosphorylation within 30 minutes both in AF and NP cells (Fig. 1). PTH stimulated ERK phosphorylation was found to be sustained up to 6 hours followed by a slow decrease (Fig. 1). However, PTH led to JNK phosphorylation within 30 minutes of incubation and this declined thereafter over 48 hours. PTH stimulation of p38 MAPK phosphorylation was not altered in AF cells, whereas in NP cells there was a significant activation of p38 at 30 minutes by PTH. There was a decline in p38 phosphorylation below the control levels after 24 hours of incubation with PTH. Effect of PTH on AKT signaling Results show that PTH causes AKT ( ser 473) activation by phosphorylation at 1 hour in NP cells and has no effect in AF cells. Effect of PTH on Calcification markers The activity of alkaline phosphatase was significantly decreased by PTH after 24 hours of incubation in NP cells. In AF cells, no significant changes were observed, even though there was a trend to increase at 48 hours. PTH significantly increased calcium release into the medium at 48 hours in NP cells and no significant change was observed in AF cells Conclusion PTH has previously been shown to promote chondrogenesis and to inhibit the expression of COL-X in chondrocytes probably via the activation of MAPK signaling pathways. 4 The present results demonstrate that PTH upregulates COL-II and downregulates COL-X in IVD cells, indicating that PTH has the potential of being able to stimulate disk repair and to improve nutrient supply in the degenerative disc. Our data also suggests that activation of MAPK pathway takes place much earlier than the alterations in COL-II or COL-X expression. Interestingly, COL-II expression inversely correlates with alkaline phosphatase activity in NP cells treated with PTH. Although understanding of IVD calcification would be of great value, not only for elucidation of its mechanism, but with an eye toward eventual therapeutic intervention. PTH can thus be used towards disk regeneration therapy. I confirm having declared any potential conflict of interest for all authors listed on this abstract Yes Disclosure of Interest None declared Hristova, GI et al. Journal of Orthopaedic Research 2011; epub Mwale F et al. Tissue Engeneering Part A (2010)16:3449–3455 Chelberg MK et al. Journal of Anatomy 1995;186 (Pt 1): 43–53 Datta, NS et al. Cell Signalling 2010;22: 457–46
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».