Skip to main content
NCBI home page
Journal of Dental Sciences logoLink to Journal of Dental Sciences
. 2023 Feb 9;18(3):1219–1226. doi: 10.1016/j.jds.2023.01.029

Lysophosphatidic acid induces proliferation and osteogenic differentiation of human dental pulp stem cell through lysophosphatidic acid receptor 3/extracellular signal-regulated kinase signaling axis

Soon Chul Heo a,1, Bo Ram Keum a,1, Eun Jin Seo b, Jinhwan Yoon c, Sanghwa Jeong d, Gabor J Tigyi e, Derek Norman e, Il Ho Jang b, Hyung Joon Kim a,∗
PMCID: PMC10316439  PMID: 37404649

Abstract

Background/purpose

Human dental pulp stem cells (hDPSCs) possess excellent proliferative and osteogenic differentiation potentials. This study aimed to elucidate the role of lysophosphatidic acid (LPA) signaling in the proliferation and osteogenic differentiation of hDPSCs.

Materials and methods

hDPSCs were treated with LPA and proliferation was measured using the cell counting kit-8 assay. Following the osteogenic differentiation of hDPSCs using osteogenic medium in the presence or absence of LPA, alkaline phosphatase (ALP) staining, ALP activity measurements, and RT-qPCR were performed to analyze the osteoblast differentiation. Small interfering RNA (siRNA)-mediated LPAR3 silencing and extracellular signal-regulated (ERK)/mitogen-activated protein (MAP) kinase inhibitors were used to elucidate the molecular mechanisms underlying LPA-induced proliferation and differentiation of hDPSCs.

Results

LPA treatment significantly induced proliferation and osteogenic differentiation of hDPSCs. The depletion of LPAR3 expression by LPAR3-speicifc siRNA in hDPSCs diminished LPA-induced proliferation and osteogenic differentiation. The LPAR3-mediated proliferation and osteogenic differentiation of hDPSCs in response to LPA were significantly suppressed by U0126, a selective inhibitor of ERK.

Conclusion

These findings suggest that LPA induces the proliferation and osteogenic differentiation of hDPSCs via LPAR3-ERK-dependent pathways.

Keywords: Human dental pulp stem cells, Lysophosphatidic acid, Osteogenic differentiation, Proliferation

Introduction

The central pulp cavity of each human tooth is occupied by unmineralized oral tissues, known as the dental pulp, composed of vascular lymphatic vessels, connective tissue, and nerve elements. Dental pulp is composed of several cellular components, including fibroblasts, endothelial cells, osteoblasts, and odontoblasts.1 The first human dental pulp stem cells (hDPSCs) have been characterized from impacted human third molars in 2000. They have received extensive attention in the field of regenerative medicine and tissue engineering owing to their high proliferative and multi-lineage differentiation potential. hDPSCs generate a dentin-like matrix and an odontoblast-like layer when transplanted in conjugation with hydroxyapatite/tricalcium phosphate into immunocompromised mice.2 Furthermore, osteogenic differentiation of hDPSCs represents similar matrix proteins associated with mineralized tissue such as alkaline phosphates, osteocalcin, and osteopontin, suggesting a possible resource in the repair and regeneration of bone.3 A pilot clinical study demonstrated safety and potential efficacy of autologous transplantation of hDPSCs for pulp regeneration in pulpectomized teeth. Implantation of DPSC into the empty root canal resulted in a functional dentin formation in three of five patients with irreversible post-traumatic pulpitis.4 Therefore, improving the osteogenic differentiation efficacy of hDPSCs is crucial for more effective therapeutic applications of hDPSC-based therapy.

Lysophosphatidic acid (LPA) is a bioactive lipid molecule that has emerged as an important signaling regulator of many different biological functions such as proliferation, cytoskeletal changes, cell motility, and differentiation.5,6 LPA can be produced from hydrolysis of lysophosphatidylcholine by autotaxin, which has plasma lysophospholipase D activity, and is present in the nanomolar range in plasma, increasing to micromoles in serum.7,8 Since the first cognate cell surface type 1 receptor for LPA was identified in 1996, five additional LPA receptors, which can couple to multiple heterotrimeric G proteins, have been identified.9 A complex interplay between LPA and LPA receptors can trigger several downstream signaling cascades through elevation of cytosolic free calcium concentration, rho-kinase, extracellular signal-regulated kinases (ERK), and mitogen-activated protein kinases (MAPK) signaling pathways.10

Accumulating evidence demonstrate that most skeletal cell types, including osteoblasts, express LPA receptors, and it is involved in bone cell differentiation, skeletal development, and bone disorders.11, 12, 13 Conditional knockout of LPAR1 in the osteoblastic lineage caused reduced the bone mineralization as well as increased the bone porosity in mice. Immortalized LPAR1 deficient osteoblast exhibited a remarkable mineralization defect associated with decreased YAP nuclear accumulation in vitro.14 In addition, LPAR4 showed inhibitory effects on osteogenesis. Downregulation of LPAR4 in bone marrow stem cells, which are common mesenchymal progenitors of osteoblasts, leads to increased mineralization, and Lpar4-deficient mice have a high bone mass phenotype,15 suggesting a pivotal role for LPAR signaling in osteogenesis. However, the role of LPAR3 signaling in osteogenesis has not yet been demonstrated.

In this study, we investigated whether the LPA-LPAR3 signaling axis could be a potential target for the therapeutic application of hDPSCs, focusing on proliferation and osteogenic differentiation.

Materials and methods

Reagents

Minimum essential medium with alpha modifications (α-MEM) was purchased from Welgene, Inc. (Daegu, Republic of Korea). Fetal bovine serum (FBS), trypsin-ethylenediaminetetraacetic acid (EDTA), and penicillin-streptomycin were purchased from Gibco (Thermo Fisher Scientific Inc., Waltham, MA, USA). The LPA was provided by Dr. Jae Ho Kim (Pusan National University, Yangsan, Republic of Korea). U0126 and SB203580 were purchased from Sigma-Aldrich (St. Louis, MO, USA). Antibodies against ERK, p-ERK, p38, p-p38, and β-actin were purchased from Cell Signaling Technology (Danvers, MA, USA).

Cell culture

Human dental pulp stem cells and bone marrow-derived mesenchymal stem cells were purchased from ScienCell (Carlsbad, CA, USA) and cultured in α-MEM supplemented with 10% FBS in 5% CO2 at 37 °C. The cells were passaged upon reaching 90% confluence, and the cells used in all experiments had less than seven passages. LPA treatment was performed as described previously.16

Cell counting kit 8 assay

hDPSCs were seeded into 96-well plates at a density of 5 × 103 cells/well and incubated for 72 h in the absence or presence of various concentration of LPA. For inhibitor experiments, selective inhibitor for ERK or p38 (U0126 and SB203580, respectively) was pretreated 30 min, and then hDPSCs incubated in the absence or presence of LPA (10 μM) for 2 days. At the indicated time points, cell viability was assessed by adding 20 μL of cell counting kit-8 (CCK-8) solution (Dojindo, Rockville, MD, USA). Absorbance was measured at 450 nm using an Opsys MR microplate reader (DYNEX Technologies Inc., Denkendorf, Germany).

Osteoblast differentiation

Osteoblast differentiation was induced as previously described.17 In brief, hDPSCs were incubated with osteogenic medium (100 μg/mL ascorbic acid, 10 mM ꞵ-glycerophosphate, and 100 nM dexamethasone) in the absence or presence of LPA (10 μM) for 8 days, and the medium was changed every other day. For inhibitor experiments, osteogenic differentiation of hDPSCs was induced by osteogenic medium containing U0126 or SB203580, followed by LPA (10 μM) supplementation. Alkaline phosphatase (ALP) staining was conducted to verify osteoblast differentiation using an ALP assay kit (Sigma-Aldrich), according to the manufacturer's instructions. The stained images were obtained using a microscope (Nikon, Eclipse Ts2). ALP activity was measured using 1-Step PNPP substrate solution (Thermo Fisher Scientific, Waltham, MA, USA) according to the manufacturer's instructions, and the absorbance was measured at 405 nm.

RT-qPCR

Total RNA was purified using the RNeasy Mini Kit (Qiagen) according to the manufacturer's instructions, and 2 μg of RNA was reverse-transcribed under standard conditions using Superscript II (Invitrogen, Waltham, MA, USA). For qPCR analysis, 50 ng of cDNA was mixed with SYBR Green PCR Master Mix (Applied Biosystems, Foster City, CA, USA) and amplified for 40 cycles using an AB7500 system (Applied Biosystems). Experiments were performed in triplicate and the data were normalized to those of β-actin. The data were analyzed using the 2–ΔΔCt method. The primer sequences used were as follows: ALP,5′-GCTGTAAGGACATCGCCTACCA-3′, 5′-CCTGGCTTTCTCGTCACTCTCA-3′; OPN,5′-GCCAGCAACCGAAGTTTTCAC-3′, 5′-TGCACCATTCAACTCCTCGC-3′; OSX,5′-TCCCTGCTTGAGGAGGAAG-3′, 5′-AGTTGTTGAGTCCCGCAGAG-3′; LPAR3,5′-CCGCATACAAGTGGGTCCAT-3′, 5′-GTCCAGCATACCACAAACGC-3’; β-actin,5′-ACTCTTCCAGCCTTCCTTCC-3′, 5′-TGTTGGCGTACAGGTCTTTG-3′.

Transfection with siRNA

siRNAs for human LPAR3 and non-specific control siRNA were purchased from GenePharma (Shanghai, China): siLPAR3, 5′-GCCUAUGUAUUCCUGAUGUTT-3′ (sense) 5′-ACAUCAGGAAUACAUAGGCTT-3′(antisense); siControl, 5′-UUCUCCGAACGUGUCACGUTT-3′ (sense), and 5′-ACGUGACACGUUCGGAGAATT-3′ (antisense). siRNA transfection was performed using jetPRIME reagent (Polyplus, New York, USA). Briefly, the respective siRNAs were diluted in jetPRIME buffer, and jetPRIME reagent was added. After 10 min of incubation, the transfection mix was added dropwise to the cells. After incubation of hDPSCs with the transfection reagent containing siRNA for 6 h, the transfection medium was replaced with a fresh medium.

Western blotting

For the analysis of phosphorylation of ERK and p38, hDPSCs were incubated with LPA (10 μM) for 15 or 30 min. For the analysis of phosphorylation with siRNA-transfected hDPSCs, cells were treated with LPA (10 μM) for 30 min. Cell lysates were collected using RIPA buffer (50 mM Tris, pH 8.0, 150 mM NaCl, 0.5% sodium deoxycholate, 1 mM EGTA, 1% Triton X-100, 10 mM NaF, PMSF, and complete protease inhibitor cocktail). Protein lysates (20 μg) were separated using SDS-PAGE (10% or 15% gels). After transferring the separated protein bands onto nitrocellulose membranes, the membranes were blocked with 5% skimmed milk for 1 h. The membranes were incubated with the appropriate primary antibodies for 16 h, followed by incubation with HRP-conjugated secondary antibodies for 1 h. Immunoreactivity was detected using enhanced chemiluminescence reagents (Amersham Pharmacia Biotech Ltd.). Comparable loading was confirmed using anti-β-actin antibody.

Statistical analyses

For multiple comparisons, one-way or two-way analysis of variance (ANOVA) with Bonferroni post-hoc test was used. Differences were considered statistically significant at P < 0.05. All data are presented as mean ± SD, and the results are representative of at least three independent experiments.

Results

LPA stimulates proliferation and osteogenic differentiation of hDPSCs

To evaluate the question of whether LPA can stimulate proliferation of hDPSCs, we measured the proliferation of hDPSCs following the LPA administration using CCK-8 assay. Treatment of hDPSCs with LPA significantly stimulated their proliferation in a dose and time dependent manner (Fig. 1A). To examine the effects of LPA on the osteogenic differentiation of hDPSCs, we induced the osteogenic differentiation of hDPSCs with an osteogenic medium in the presence or absence of LPA. The results of ALP staining and ALP activity assays showed that the treatment with LPA potentiated the osteogenic medium-induced ALP-positive populations and ALP activity in hDPSCs (Fig. 1B and C). Treatment with LPA further stimulated the osteogenic medium-mediated mRNA expression of osteogenic-specific genes including ALP, OPN, and OSX (Fig. 1D). These findings indicate that LPA stimulates the proliferation and osteogenic differentiation of hDPSCs.

Figure 1.

Fig. 1

Open in a new tab

Effects of LPA on proliferation and osteogenic differentiation of hDPSCs. (A) Time and dose dependence of LPA-induced hDPSCs proliferation. hDPSCs were incubated for indicated concentration of LPA for 24 h (left) and were incubated for indicated time in the absence or presence of 10 μM LPA (right). Relative proliferation ratio was measured using CCK-8 assay. (B–D) Osteogenic differentiation of hDPSCs was induced by osteogenic medium in the absence or presence of LPA (10 μM) for 8 days. (B) Representative images of ALP staining and quantitative analysis of ALP-positive area. Scale bars = 200 μm. (C) Quantitative analysis of ALP activity. (D) mRNA expression of ALP, OPN, and OSX was determined by qRT-PCR and normalized to the expression of ꞵ-actin. Data are shown as means ± SD. ∗P < 0.05, ∗∗P < 0.01, and ∗∗∗P < 0.001, one-way or two-way ANOVA. LPA, lysophosphatidic acid; GM, growth medium; OM, osteogenic medium; n.s., not significant.

LPAR3 is responsible for LPA-induced proliferation and osteogenic differentiation of hDPSCs

To examine which LPA receptor is responsible for LPA-induced proliferation and osteogenic differentiation, we first compared the mRNA expression of hDPSCs with that of bone marrow mesenchymal stem cell (BMMSCs), the major cellular source for osteoblastogenesis,18 using qRT-PCR. Four of the six LPAR were upregulated in hDPSCs compared to BMMSCs, and LPAR3 was the most potent (Fig. 2A). To clarify the involvement of LPAR3 in LPA-induced proliferation and osteogenic differentiation of hDPSCs, we examined the effects of siRNA-mediated LPAR3 silencing on the proliferation and osteogenic differentiation of hDPSCs. Transfection with LPAR3-specific siRNA resulted in downregulation of mRNA expression of LPAR3 in hDPSCs (Fig. 2B). The LPA-induced proliferation of hDPSCs was significantly abrogated by LPAR3 silencing (Fig. 2C). In addition, silencing of LPAR resulted in a markedly diminished LPA-induced ALP-positive population and ALP activity (Fig. 2D and E). The analysis of mRNA expression using qRT-PCR further confirmed that the LPA-induced osteogenic-specific genes were downregulated by LPAR3 silencing in hDPSCs (Fig. 2F). Taken together, these results suggest that LPAR3 plays a key role in the LPA-stimulated proliferation and osteogenic differentiation of hDPSCs.

Figure 2.

Fig. 2

Open in a new tab

Role of LPAR3 in LPA-induced proliferation and osteogenic differentiation of hDPSCs. (A) mRNA expression of LPA receptors in BMMSCs and DPSCs was compared by qRT-PCR. (B) Silencing of LPAR3 in hDPSCs was verified by qRT-PCR on day 2 and 8. (C) hDPSCs transfected with siControl or siLPAR3 were incubated in the absence or presence of LPA (10 μM) for 2 days. Relative proliferation ratio was measured using CCK-8 assay. (D–F) Osteogenic differentiation of hDPSCs transfected with siControl or siLPAR3 was induced by osteogenic medium in the absence or presence of LPA (10 μM) for 8 days. (D) Representative images of ALP staining and quantitative analysis of ALP-positive area. Scale bars = 200 μm. (C) Quantitative analysis of ALP activity. (D) mRNA expression of ALP, OPN, and OSX was determined by qRT-PCR and normalized to the expression of ꞵ-actin. Data are shown as means ± SD. ∗P < 0.05, ∗∗P < 0.01, and ∗∗∗P < 0.001, one-way or two-way ANOVA. LPA, lysophosphatidic acid; GM, growth medium; OM, osteogenic medium; n.s., not significant.

MAP kinases mediate LPA-induced proliferation and differentiation of hDPSCs

LPA-induced LPAR activation is mediated by MAP kinases, including ERK and p38 MAPK.19,20 To clarify the involvement of MAP kinases in the LPA-induced proliferation and differentiation of hDPSCs, we examined the effects of LPA on MAP kinase phosphorylation using western blotting. As shown in Fig. 3A, the LPA administration induced phosphorylation of ERK and p38 MAPK in a time-dependent manner. Furthermore, the LPA-induced phosphorylation of ERK and p38 MAPK was blocked by the transfection of hDPSCs with LPAR3-specific siRNA, suggesting that LPAR3 is involved in the LPA-induced phosphorylation of ERK and p38 MAPK in hDPSCs (Fig. 3B).

Figure 3.

Fig. 3

Open in a new tab

Effects of LPA on phosphorylation of ERK and p38 MAP kinase. (A) hDPSCs were incubated with LPA (10 μM) for indicated time. Phosphorylation of ERK and p38 was determined by western blotting. ꞵ-Actin served as a loading control. (B) hDPSCs were transfected with siControl or siLPAR3, and treated with LPA (10 μM) for 30 min. Phosphorylation of ERK and p38 was determined by western blotting. ꞵ-Actin served as a loading control. LPA, lysophosphatidic acid.

ERK is involved in the LPA-induced proliferation and differentiation of hDPSCs

To assess the involvement of ERK and p38 MAPK in LPA-induced proliferation and osteogenic differentiation, we examined the effects of U0126 and SB203580, a specific inhibitor for ERK and p38 MAPK, respectively, on LPA-stimulated proliferation and osteogenic differentiation of hDPSCs. Pre-treatment of hDPSCs with U0126, but not SB203580, significantly suppressed the LPA-induced proliferation of hDPSCs (Fig. 4A). In addition, treatment with U0126 significantly reduced the LPA-mediated ALP-positive populations and ALP activity in hDPSCs upon osteogenic differentiation (Fig. 4B and C). qRT-PCR results revealed that the LPA-induced osteogenic-specific genes were markedly abrogated by U0126 but not by SB203580 (Fig. 4D). Collectively, these results demonstrate that LPA induces the proliferation and osteogenic differentiation of hDPSCs via an ERK-dependent mechanism.

Figure 4.

Fig. 4

Open in a new tab

Involvement of ERK signaling pathway in LPA-induced proliferation and osteogenic differentiation of hDPSCs. (A) hDPSCs were incubated in the absence or presence of LPA (10 μM) for 2 days. Selective inhibitor for ERK or p38 (U0126 and SB203580, respectively) was pretreated 30 min prior to LPA treatment. Relative proliferation ratio was measured using CCK-8 assay. (B–D) Osteogenic differentiation of hDPSCs was induced by osteogenic medium containing U0126 or SB203580, followed by LPA (10 μM) supplementation. (B) Representative images of ALP staining and quantitative analysis of ALP-positive area. Scale bars = 200 μm. (C) Quantitative analysis of ALP activity. (D) mRNA expression of ALP, OPN, and OSX were determined by qRT-PCR and normalized to the expression of ꞵ-actin. Data are shown as means ± SD. ∗P < 0.05, ∗∗P < 0.01, and ∗∗∗P < 0.001, one-way or two-way ANOVA. LPA, lysophosphatidic acid; GM, growth medium; OM, osteogenic medium; n.s., not significant.

Discussion

DPSCs have been demonstrated to share a similar property with BMMSCs, such as surface markers, fibroblast-like morphology, adherence and colony-forming capabilities.21 Alge et al. compared these two types of cells regarding their proliferation, clonogenic and mineralization potential with donor-matched rat model. They demonstrated that DPSCs have a faster cell growth rate and a higher stem/progenitor population, which may possess increased mineralization potential.22 To examine the cause of the difference in osteogenic differentiation ability between DPSCs and BMMSCs, we focused on the LPA signaling since it has been reported to contribute to mineral homeostasis and bone remodeling.23 Although DPSCs share many characteristics with BMMSCs, they showed distinct mRNA expression levels of LPAR compared to BMMSCs. In this study, we found that the LPAR3 transcript in DPSCs was expressed at a level 60-fold higher than that of the transcript in BMMSCs, and it was the most potent among LPA receptors. To the best of our knowledge, the role of LPAR3 in bone biology has not been studied. The proliferation of chondrocytes in plate cartilage is crucial for bone growth, and LPAR3 was shown to be involved in this process via the ERK-dependent pathway.19 According to one report, LPAR3 expression was scarcely detected in the MC3T3-E1 osteoblastic cell line.24 Consistent with these results, we observed that the LPAR3 mRNA expression in hDPSCs was gradually downregulated as osteogenic differentiation progressed (data not shown). We speculate that LPAR3 is more responsible for early commitment to osteoblastogenesis than the mature process in hDPSCs, which remains to be further explored.

Dental pulp repair is a progressive and successive process, including cell migration, proliferation, differentiation, and remodeling, which ultimately generates tertiary dentin.25 Cheng et al. have shown that LPA effectively improves the regenerative capacity of human dental pulp cells. Cell migration and adhesion are induced by LPA stimulation through the Rho-associated kinase pathway, thereby contributing to the dental pulp healing process.26,27 Recent advances in biomaterial studies have supported the therapeutic use of LPA in bone regeneration. Mansell et al. clearly shown that albumin-bound LPA synergistically co-operated with calcitriol to markedly increase maturation of human MG63 cells at widely used bone biomaterials, hydroxyapatite and titanium.28 Furthermore, Bosetti et al. developed a three-dimensional injectable collagen gel containing LPA and 1α,25-dihydroxyvitamin D3 that can fasten bone fragments and accelerate new bone formation.29 In this study, we showed that LPA enhances the proliferation and osteogenic differentiation of hDPSCs in vitro. Although we did not evaluate the effects of dentin-specific genes such as Dspp and Dmp1, the expression of marker genes for odontogenic differentiation (ALP, OPN, OSX) was significantly potentiated by LPA treatment upon osteogenic differentiation. These results suggest that LPA signaling may be a potential target for the regeneration of dental pulp by regulating multiple repair processes.

In the present study, we demonstrated that LPA promotes the proliferation and osteogenic differentiation of hDPSCs via an ERK-dependent pathway. Treatment with U0126, a specific inhibitor of ERK, significantly diminished LPA-mediated hDPSCs proliferation and osteogenic differentiation; however, SB203580, a specific inhibitor of p38, did not. Consistent with our findings, numerous studies have shown that ERK is responsible for the LPA-mediated cellular mechanisms. Karagiosis et al. verified that ERK is a mediator of LPA-induced MC3T3-E1 cell migration and ERK participates in the LPA-induced rat primary chondrocyte proliferation.19,30 Jaiswal et al. provided evidence that sustained activation of ERK signaling is positively correlated with osteogenic gene expression, such as osteopontin, in human mesenchymal stem cells.31 Furthermore, Ge et al. identified two phosphorylation sites in Runx2, which is a master transcription factor of osteoblast differentiation, at Ser301 and Ser319 that are essential for ERK-dependent Runx2 activation.32 These results support those of this study showing that ERK plays a crucial role in the LPA-induced osteoblast differentiation of hDPSCs.

In conclusion, we addressed the question of whether LPA signaling stimulates the cellular responses of hDPSCs. This study demonstrated that LPA stimulated the proliferation and osteogenic differentiation of hDPSCs through the LPAR3-ERK-dependent pathway. Overall, this study provides a novel therapeutic strategy for hDPSC-based bone-regeneration therapy.

Declaration of competing interest

The authors declare no conflicts of interest regarding the publication of this article.

Acknowledgments

This research was supported by the PNU-RENovation (2022–2023).

References

  • 1.Baume L.J. The biology of pulp and dentine. A historic, terminologic-taxonomic, histologic-biochemical, embryonic and clinical survey. Monogr Oral Sci. 1980;8:1–220. [PubMed] [Google Scholar]
  • 2.Gronthos S., Mankani M., Brahim J., Robey P.G., Shi S. Postnatal human dental pulp stem cells (DPSCs) in vitro and in vivo. Proc Natl Acad Sci U S A. 2000;97:13625–13630. doi: 10.1073/pnas.240309797. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 3.Kim B.C., Bae H., Kwon I.K., et al. Osteoblastic/cementoblastic and neural differentiation of dental stem cells and their applications to tissue engineering and regenerative medicine. Tissue Eng B Rev. 2012;18:235–244. doi: 10.1089/ten.teb.2011.0642. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 4.Nakashima M., Iohara K., Murakami M., et al. Pulp regeneration by transplantation of dental pulp stem cells in pulpitis: a pilot clinical study. Stem Cell Res Ther. 2017;8:61. doi: 10.1186/s13287-017-0506-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 5.Fukushima N., Ishii I., Contos J.J., Weiner J.A., Chun J. Lysophospholipid receptors. Annu Rev Pharmacol Toxicol. 2001;41:507–534. doi: 10.1146/annurev.pharmtox.41.1.507. [DOI] [PubMed] [Google Scholar]
  • 6.Ishii I., Fukushima N., Ye X., Chun J. Lysophospholipid receptors: signaling and biology. Annu Rev Biochem. 2004;73:321–354. doi: 10.1146/annurev.biochem.73.011303.073731. [DOI] [PubMed] [Google Scholar]
  • 7.van Meeteren L.A., Ruurs P., Stortelers C., et al. Autotaxin, a secreted lysophospholipase D, is essential for blood vessel formation during development. Mol Cell Biol. 2006;26:5015–5022. doi: 10.1128/MCB.02419-05. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 8.Hosogaya S., Yatomi Y., Nakamura K., et al. Measurement of plasma lysophosphatidic acid concentration in healthy subjects: strong correlation with lysophospholipase D activity. Ann Clin Biochem. 2008;45:364–368. doi: 10.1258/acb.2008.007242. [DOI] [PubMed] [Google Scholar]
  • 9.Kihara Y., Maceyka M., Spiegel S., Chun J. Lysophospholipid receptor nomenclature review: IUPHAR Review 8. Br J Pharmacol. 2014;171:3575–3594. doi: 10.1111/bph.12678. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 10.Yung Y.C., Stoddard N.C., Chun J. LPA receptor signaling: pharmacology, physiology, and pathophysiology. J Lipid Res. 2014;55:1192–1214. doi: 10.1194/jlr.R046458. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 11.Blackburn J., Mansell J.P. The emerging role of lysophosphatidic acid (LPA) in skeletal biology. Bone. 2012;50:756–762. doi: 10.1016/j.bone.2011.12.002. [DOI] [PubMed] [Google Scholar]
  • 12.Yu Z.L., Jiao B.F., Li Z.B. Lysophosphatidic acid analogue rather than lysophosphatidic acid promoted the bone formation in vivo. BioMed Res Int. 2018;2018 doi: 10.1155/2018/7537630. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 13.Orosa B., Gonzalez A., Mera A., Gomez-Reino J.J., Conde C. Lysophosphatidic acid receptor 1 suppression sensitizes rheumatoid fibroblast-like synoviocytes to tumor necrosis factor-induced apoptosis. Arthritis Rheum. 2012;64:2460–2470. doi: 10.1002/art.34443. [DOI] [PubMed] [Google Scholar]
  • 14.Alioli C.A., Demesmay L., Laurencin-Dalacieux S., et al. Expression of the type 1 lysophosphatidic acid receptor in osteoblastic cell lineage controls both bone mineralization and osteocyte specification. Biochim Biophys Acta Mol Cell Biol Lipids. 2020;1865 doi: 10.1016/j.bbalip.2020.158715. [DOI] [PubMed] [Google Scholar]
  • 15.Liu Y.B., Kharode Y., Bodine P.V., Yaworsky P.J., Robinson J.A., Billiard J. LPA induces osteoblast differentiation through interplay of two receptors: LPA1 and LPA4. J Cell Biochem. 2010;109:794–800. doi: 10.1002/jcb.22471. [DOI] [PubMed] [Google Scholar]
  • 16.Jeong G.O., Shin S.H., Seo E.J., et al. TAZ mediates lysophosphatidic acid-induced migration and proliferation of epithelial ovarian cancer cells. Cell Physiol Biochem. 2013;32:253–263. doi: 10.1159/000354434. [DOI] [PubMed] [Google Scholar]
  • 17.Heo S.C., Kim Y.N., Keum B.R., Joo J.Y., Bae M.K., Kim H.J. Vasohibin-1 promotes osteoclast differentiation in periodontal disease by stimulating the expression of RANKL in gingival fibroblasts. Biochim Biophys Acta, Mol Basis Dis. 2022;1869 doi: 10.1016/j.bbadis.2022.166632. [DOI] [PubMed] [Google Scholar]
  • 18.Matic I., Matthews B.G., Wang X., et al. Quiescent bone lining cells are a major source of osteoblasts during adulthood. Stem Cell. 2016;34:2930–2942. doi: 10.1002/stem.2474. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 19.Kim M.K., Lee H.Y., Park K.S., et al. Lysophosphatidic acid stimulates cell proliferation in rat chondrocytes. Biochem Pharmacol. 2005;70:1764–1771. doi: 10.1016/j.bcp.2005.09.015. [DOI] [PubMed] [Google Scholar]
  • 20.Zhou Z.B., Niu J.P., Zhang Z.J. Receptor-mediated vascular smooth muscle migration induced by LPA involves p38 mitogen-activated protein kinase pathway activation. Int J Mol Sci. 2009;10:3194–3208. doi: 10.3390/ijms10073194. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 21.Huang G.T., Gronthos S., Shi S. Mesenchymal stem cells derived from dental tissues vs. those from other sources: their biology and role in regenerative medicine. J Dent Res. 2009;88:792–806. doi: 10.1177/0022034509340867. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 22.Alge D.L., Zhou D., Adams L.L., et al. Donor-matched comparison of dental pulp stem cells and bone marrow-derived mesenchymal stem cells in a rat model. J Tissue Eng Regen Med. 2010;4:73–81. doi: 10.1002/term.220. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 23.Sims S.M., Panupinthu N., Lapierre D.M., Pereverzev A., Dixon S.J. Lysophosphatidic acid: a potential mediator of osteoblast-osteoclast signaling in bone. Biochim Biophys Acta. 2013;1831:109–116. doi: 10.1016/j.bbalip.2012.08.001. [DOI] [PubMed] [Google Scholar]
  • 24.Masiello L.M., Fotos J.S., Galileo D.S., Karin N.J. Lysophosphatidic acid induces chemotaxis in MC3T3-E1 osteoblastic cells. Bone. 2006;39:72–82. doi: 10.1016/j.bone.2005.12.013. [DOI] [PubMed] [Google Scholar]
  • 25.Goldberg M., Smith A.J. Cells and extracellular matrices of dentin and pulp: a biological basis for repair and tissue engineering. Crit Rev Oral Biol Med. 2004;15:13–27. doi: 10.1177/154411130401500103. [DOI] [PubMed] [Google Scholar]
  • 26.Cheng R., Cheng L., Shao M.Y., et al. Roles of lysophosphatidic acid and the Rho-associated kinase pathway in the migration of dental pulp cells. Exp Cell Res. 2010;316:1019–1027. doi: 10.1016/j.yexcr.2010.01.002. [DOI] [PubMed] [Google Scholar]
  • 27.Cheng R., Shao M.Y., Yang H., et al. The effect of lysophosphatidic acid and Rho-associated kinase patterning on adhesion of dental pulp cells. Int Endod J. 2011;44:2–8. doi: 10.1111/j.1365-2591.2010.01773.x. [DOI] [PubMed] [Google Scholar]
  • 28.Mansell J.P., Barbour M., Moore C., et al. The synergistic effects of lysophosphatidic acid receptor agonists and calcitriol on MG63 osteoblast maturation at titanium and hydroxyapatite surfaces. Biomaterials. 2010;31:199–206. doi: 10.1016/j.biomaterials.2009.09.035. [DOI] [PubMed] [Google Scholar]
  • 29.Bosetti M., Borrone A., Leigheb M., Shastri V.P., Cannas M. Injectable graft substitute active on bone tissue regeneration. Tissue Eng. 2017;23:1413–1422. doi: 10.1089/ten.TEA.2016.0554. [DOI] [PubMed] [Google Scholar]
  • 30.Karagiosis S.A., Chrisler W.B., Bollinger N., Karin N.J. Lysophosphatidic acid-induced ERK activation and chemotaxis in MC3T3-E1 preosteoblasts are independent of EGF receptor transactivation. J Cell Physiol. 2009;219:716–723. doi: 10.1002/jcp.21720. [DOI] [PubMed] [Google Scholar]
  • 31.Jaiswal R.K., Jaiswal N., Bruder S.P., Mbalaviele G., Marshak D.R., Pittenger M.F. Adult human mesenchymal stem cell differentiation to the osteogenic or adipogenic lineage is regulated by mitogen-activated protein kinase. J Biol Chem. 2000;275:9645–9652. doi: 10.1074/jbc.275.13.9645. [DOI] [PubMed] [Google Scholar]
  • 32.Ge C., Xiao G., Jiang D., et al. Identification and functional characterization of ERK/MAPK phosphorylation sites in the Runx2 transcription factor. J Biol Chem. 2009;284:32533–32543. doi: 10.1074/jbc.M109.040980. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Journal of Dental Sciences are provided here courtesy of Association for Dental Sciences of the Republic of China

RESOURCES