Continuous PTH modulates alkaline phosphatase activity in human PDL cells via protein kinase C dependent pathways in vitro

Wolf, Michael; Jäger, Andreas; Abuduwali, Nuersailike; Götz, Werner; Lossdörfer, Stefan

doi:10.1016/j.aanat.2013.04.006

Cited by 9 publications

(10 citation statements)

References 30 publications

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“…Despite this, Alpl expression was induced in response to PTH in MC3T3-C14 cell cultures. An enhancement of Alpl expression and TNAP activity in response to a continuous exposure to PTH has previously been shown in periodontal ligament cells [ 45 ] and in the UMR-106 cell line [ 46 ], respectively. Even with this body of evidence in mind, the differential regulation of Phospho1 and Alpl by PTH is perhaps surprising.…”

Section: Discussionmentioning

confidence: 93%

“…These data are novel for the PTH control of Phospho1 and Smpd3 expression, but previous reports have demonstrated the involvement of the cAMP-PKA pathway in the regulation (both positive and negative) of TNAP activity in a variety of cell culture models of mineralisation [ 33 , 40 , 45 , 46 ]. The PTH-dependent enhancement of TNAP activity has been shown to be enacted through cAMP-PKA-mediated activation of p38 MAP kinase [ 53 ].…”

Section: Discussionmentioning

confidence: 98%

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The Expression of PHOSPHO1, nSMase2 and TNAP is Coordinately Regulated by Continuous PTH Exposure in Mineralising Osteoblast Cultures

et al. 2016

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Sustained exposure to high levels of parathyroid hormone (PTH), as observed in hyperparathyroidism, is catabolic to bone. The increase in the RANKL/OPG ratio in response to continuous PTH, resulting in increased osteoclastogenesis, is well established. However, the effects of prolonged PTH exposure on key regulators of skeletal mineralisation have yet to be investigated. This study sought to examine the temporal expression of PHOSPHO1, TNAP and nSMase2 in mineralising osteoblast-like cell cultures and to investigate the effects of continuous PTH exposure on the expression of these enzymes in vitro. PHOSPHO1, nSMase2 and TNAP expression in cultured MC3T3-C14 cells significantly increased from day 0 to day 10. PTH induced a rapid downregulation of Phospho1 and Smpd3 gene expression in MC3T3-C14 cells and cultured hemi-calvariae. Alpl was differentially regulated by PTH, displaying upregulation in cultured MC3T3-C14 cells and downregulation in hemi-calvariae. PTH was also able to abolish the stimulatory effects of bone morphogenic protein 2 (BMP-2) on Smpd3 and Phospho1 expression. The effects of PTH on Phospho1 expression were mimicked with the cAMP agonist forskolin and blocked by the PKA inhibitor PKI (5-24), highlighting a role for the cAMP/PKA pathway in this regulation. The potent down-regulation of Phospho1 and Smpd3 in osteoblasts in response to continuous PTH may provide a novel explanation for the catabolic effects on the skeleton of such an exposure. Furthermore, our findings support the hypothesis that PHOSPHO1, nSMase2 and TNAP function cooperatively in the initiation of skeletal mineralisation.

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Section: Discussionmentioning

confidence: 93%

Section: Discussionmentioning

confidence: 98%

The Expression of PHOSPHO1, nSMase2 and TNAP is Coordinately Regulated by Continuous PTH Exposure in Mineralising Osteoblast Cultures

et al. 2016

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“…We knocked down GNAQ and GNA11 (100% and 88% knockdown efficiency, respectively) (data not shown) using siRNA and concluded that Gαq/11 signaling is involved in TSH-mediated up-regulation of ALPL as we observed a 87.4% reduction of the TSH effect ( Figure 8 A). Because it had been previously shown that ALPL activity was modulated by PTH in periodontal ligament cells via a PKC-dependent pathway ( 18 ), we explored a role for PKC in ALPL up-regulation by TSH in our system. We used the PKC inhibitor GFX and demonstrated that ALPL up-regulation by TSH was 81.5% lower than control in GFX-treated cells ( Figure 8 B) and conversely, the PKC activator phorbol 12, 13-dibutyrate treatment increased basal ALPL expression level 4.7-fold ( Figure 8 C).…”

Section: Resultsmentioning

confidence: 99%

Multiple Transduction Pathways Mediate Thyrotropin Receptor Signaling in Preosteoblast-Like Cells

2016

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It has been shown that the TSH receptor (TSHR) couples to a number of different signaling pathways, although the Gs-cAMP pathway has been considered primary. Here, we measured the effects of TSH on bone marker mRNA and protein expression in preosteoblast-like U2OS cells stably expressing TSHRs. We determined which signaling cascades are involved in the regulation of IL-11, osteopontin (OPN), and alkaline phosphatase (ALPL). We demonstrated that TSH-induced up-regulation of IL-11 is primarily mediated via the Gs pathway as IL-11 was up-regulated by forskolin (FSK), an adenylyl cyclase activator, and inhibited by protein kinase A inhibitor H-89 and by silencing of Gαs by small interfering RNA. OPN levels were not affected by FSK, but its up-regulation was inhibited by TSHR/Gi-uncoupling by pertussis toxin. Pertussis toxin decreased p38 MAPK kinase phosphorylation, and a p38 inhibitor and small interfering RNA knockdown of p38α inhibited OPN induction by TSH. Up-regulation of ALPL expression required high doses of TSH (EC50 = 395nM), whereas low doses (EC50 = 19nM) were inhibitory. FSK-stimulated cAMP production decreased basal ALPL expression, whereas protein kinase A inhibition by H-89 and silencing of Gαs increased basal levels of ALPL. Knockdown of Gαq/11 and a protein kinase C inhibitor decreased TSH-stimulated up-regulation of ALPL, whereas a protein kinase C activator increased ALPL levels. A MAPK inhibitor and silencing of ERK1/2 inhibited TSH-stimulated ALPL expression. We conclude that TSH regulates expression of different bone markers via distinct signaling pathways.

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“…After adding PTH (7–34), a common antagonist of the PTHR1 which lacks the PKA‐activating domain, 39 the inhibition effect was restricted. The binding capacity of PTHrP and PTHR1 might be impaired as the PTH (7–34) competitively bond to PTHR1, 40 leading to a recovery of osteogenic differentiation of hPDLCs. Likewise, the PTHrP siRNA significantly retarded the inhibition of the osteogenic induction of PTHrP.…”

Section: Discussionmentioning

confidence: 99%

PTH/PTHrP in controlled release hydrogel enhances orthodontic tooth movement by regulating periodontal bone remodaling

Yang

et al. 2021

J of Periodontal Research

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Objective This study aimed to evaluate the effects of local application of parathyroid hormone (PTH) or parathyroid hormone‐related protein (PTHrP) on osteogenesis and osteoclastogenesis during orthodontic tooth movement (OTM). Background Periodontal bone remodeling is the crucial biological process in the OTM that involves both bone resorption and formation, with the former more important as the initiator. PTH or PTHrP both play dual roles in bone remodeling regulation, and the balance may shift to the bone resorption side when they are given continuously, suggesting them as potential candidate medicine for OTM acceleration. Methods A total of 40 rats underwent orthodontic mesialization of the maxillary first molars and received no micro‐perforation (MOP), or MOP followed by injection of temperature‐sensitive hydrogel containing PTH, PTHrP, or normal saline. The rats were sacrificed after 2‐week OTM, except for the relapse groups, which had one more week of observation after removal of the force appliances. The amount of tooth movement, rate of relapse after OTM, and effects on the bone remodeling were assessed through micro‐computed tomography (μCT) analysis, alkaline phosphatase (ALP) assay, alizarin red staining, tartrate‐resistant acid phosphatase (TRAP) staining, immunohistochemistry (IHC) analysis, Western blot (WB), and quantitative real‐time polymerase chain reaction (qRT‐PCR). The effects of PTHrP on the osteogenic differentiation of human periodontal ligament cells (hPDLCs) were explored in vitro. Results The cumulative release of PTH or PTHrP from PECE hydrogels was beyond 75% at 14 days in a sustained manner. After the intervention in vivo, the distance of OTM in the PTH (0.78 ± 0.06 mm) or PTHrP (0.81 ± 0.04 mm) group was significantly larger than that of the MOP only (0.51 ± 0.04 mm) or the no MOP (0.46 ± 0.05 mm) group. Moreover, PTH injection significantly reduced the rate of relapse after OTM (25.7 ± 4.3%) compared to the control (69.6 ± 6.1%). μCT analysis showed decreased BV/TV, BS/BV, and Tb.N, while increased Tb.Sp of alveolar bone in the PTH or PTHrP group. There were also more TRAP‐positive osteoclasts in the PTH or PTHrP group with a significantly enhanced ratio of receptor activator of nuclear factor‐κB ligand (RANKL)/osteoprotegerin (OPG). The protein expressions of PTH/PTHrP type 1 receptor (PTHR1), alkaline phosphatase (ALP), osteocalcin (OCN), runt‐related transcription factor 2 (RUNX2), and β‐catenin were significantly increased in the PTH or PTHrP group, as well as the gene expressions of Pth1r, Bglap, and Alpl. There was no significant difference between the effects of PTH and PTHrP. Nevertheless, inhibition of PTHrP on the osteogenic differentiation of hPDLCs was detected in vitro with decreased expression of OCN, RUNX2, COL‐1, and ALP. Conclusion Local injection of either PTH or PTHrP carried by controlled release PECE hydrogel similarly enhances OTM in rats through regulating periodontal bone remodeling, which deserves further study for potential clinical application.

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Continuous PTH modulates alkaline phosphatase activity in human PDL cells via protein kinase C dependent pathways in vitro

Cited by 9 publications

References 30 publications

The Expression of PHOSPHO1, nSMase2 and TNAP is Coordinately Regulated by Continuous PTH Exposure in Mineralising Osteoblast Cultures

The Expression of PHOSPHO1, nSMase2 and TNAP is Coordinately Regulated by Continuous PTH Exposure in Mineralising Osteoblast Cultures

Multiple Transduction Pathways Mediate Thyrotropin Receptor Signaling in Preosteoblast-Like Cells

PTH/PTHrP in controlled release hydrogel enhances orthodontic tooth movement by regulating periodontal bone remodaling

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