1
|
Abstract
The presence of stem cells within the dental-pulp tissue as well as their differentiation into a new generation of functional odontoblast-like cells constitutes an important step of the dentin-pulp regeneration. Recent investigations demonstrated that the complement system activation participates in 2 critical steps of dentin-pulp regeneration: pulp progenitor's recruitment and pulp nerve sprouting. Surprisingly, its implication in odontoblastic differentiation has not been addressed yet. Since the complement receptor C5a receptor-like 2 (C5L2) is expressed by different stem cells, the aim of this study is to investigate if the dental pulp stem cells express C5L2 and if this receptor participates in odontoblastic differentiation. Immunohistochemistry performed on human third molar pulp sections showed a perivascular co-localization of the mesenchymal stem cell markers STRO1 and C5L2. In vitro immunofluorescent staining confirmed that hDPSCs express C5L2. Furthermore, we determined by real-time polymerase chain reaction that the expression of C5L2 is highly modulated in human dental pulp stem cells (hDPSCs) undergoing odontoblastic differentiation. Moreover, we showed that this odontogenesis-regulated expression of C5L2 is specifically potentiated by the proinflammatory cytokine TNFα. Using a C5L2-siRNA silencing strategy, we provide direct evidence that C5L2 constitutes a negative regulator of the dentinogenic marker DMP1 (dentin matrix protein 1) expression by hDPSCs. Our findings suggest a direct correlation between the odontoblastic differentiation and the level of C5L2 expression in hDPSCs and identify C5L2 as a negative regulator of DMP1 expression by hDPSCs during the odontoblastic differentiation and inflammation processes. This work is the first to demonstrate the involvement of C5L2 in the biological function of stem cells, provides an important knowledge in understanding odontoblastic differentiation of dental pulp stem cells, and may be useful in future dentin-pulp engineering strategies.
Collapse
Affiliation(s)
- F Chmilewsky
- 1 Department of Oral Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - R Liang
- 1 Department of Oral Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - M Kanazawa
- 1 Department of Oral Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - I About
- 2 Department of Oral Biology, Aix Marseille Université, Marseille, France
| | - L F Cooper
- 1 Department of Oral Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - A George
- 1 Department of Oral Biology, University of Illinois at Chicago, Chicago, IL, USA
| |
Collapse
|
2
|
Chmilewsky F, About I, Chung SH. C5L2 Receptor Represses Brain-Derived Neurotrophic Factor Secretion in Lipoteichoic Acid-Stimulated Pulp Fibroblasts. J Dent Res 2016; 96:92-99. [PMID: 28033061 DOI: 10.1177/0022034516673832] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The anaphylatoxin C5a constitutes a powerful fragment generated by complement system activation. Interestingly, this complement active fragment is also an important mediator of tissue regeneration. Recent findings suggest that C5a could be an initial signal orchestrating pulp nerve sprouting beneath carious injury, a critical step in dentin-pulp regeneration. Indeed, the expression and activation of the C5a active receptor (C5aR/CD88) by injured pulp fibroblasts controls the direction of neurite outgrowth toward carious injuries by modulating the secretion of brain-derived neurotrophic factor (BDNF) by pulp fibroblasts. A second C5a receptor, C5L2, has also been cloned but has received much less attention because its interaction with the ligand induces no signaling. This work aims to investigate the role of C5L2 in pulp nerve regeneration in the secretion of BDNF by pulp fibroblasts under sites of carious injury. Using fluorescence immunostaining on human tooth sections in vivo and on primary human pulp fibroblasts in vitro, the authors reveal that C5L2 and C5aR are co-expressed by pulp fibroblasts under lipoteichoic acid (LTA) stimulation. Moreover, silencing C5L2 significantly increases BDNF secretion by LTA-stimulated pulp fibroblasts. Finally, an analysis of the subcellular distribution of C5aR and C5L2 indicates that the negative regulation of BDNF secretion by C5L2 correlates with C5aR activation and its subsequent intracellular co-localization with C5L2. Overall, the current study sheds light on the mechanism of pulp nerve regeneration by identifying C5L2 as a negative regulator of BDNF secretion by pulp fibroblasts under carious teeth. This knowledge significantly increases the understanding of the functional mechanism linking C5aR and C5L2 in pulp nerve regeneration, which may be useful in future dentin-pulp engineering strategies that target fibroblast C5L2 to induce pulp innervation.
Collapse
Affiliation(s)
- F Chmilewsky
- 1 Department of Oral Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - I About
- 2 Aix Marseille University, CNRS, ISM, Institute Movement Science, Marseille, France
| | - S H Chung
- 1 Department of Oral Biology, University of Illinois at Chicago, Chicago, IL, USA
| |
Collapse
|
3
|
Abstract
Dentin-pulp regeneration is closely linked to the presence of nerve fibers in the pulp and to the healing mechanism by sprouting of the nerve fiber’s terminal branches beneath the carious injury site. However, little is known about the initial mechanisms regulating this process in carious teeth. It has been recently demonstrated that the complement system activation, which is one of the first immune responses, contributes to tissue regeneration through the local production of anaphylatoxins such as C5a. While few pulp fibroblasts in intact teeth and in untreated fibroblast cultures express the C5a receptor (C5aR), here we show that all dental pulp fibroblasts, localized beneath the carious injury site, do express this receptor. This observation is consistent with our in vitro results, which showed expression of C5aR in lipoteichoic acid–stimulated pulp fibroblasts. The interaction of C5a, produced after complement synthesis and activation from pulp fibroblasts, with the C5aR of these cells mediated the local brain-derived neurotropic factor (BDNF) secretion. Overall, this activation guided the neuronal growth toward the lipoteichoic acid–stimulated fibroblasts. Thus, our findings highlight a new mechanism in one of the initial steps of the dentin-pulp regeneration process, linking pulp fibroblasts to the nerve sprouting through the complement system activation. This may provide a useful future therapeutic tool in targeting the fibroblasts in the dentin-pulp regeneration process.
Collapse
Affiliation(s)
- F. Chmilewsky
- Department of Oral Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - I. About
- Aix-Marseille Université, CNRS, ISM, UMR 7287, Marseille cedex 09, France
| | - S.-H. Chung
- Department of Oral Biology, University of Illinois at Chicago, Chicago, IL, USA
| |
Collapse
|
4
|
Abstract
Complement system, a major component of the natural immunity, has been recently identified as an important mediator of the dentin-pulp regeneration process through STRO-1 pulp cell recruitment by the C5a active fragment. Moreover, it has been shown recently that under stimulation with lipoteichoic acid, a complex component of the Gram-positive bacteria cell wall, human pulp fibroblasts are able to synthesize all proteins required for complement activation. However, Gram-negative bacteria, which are also involved in tooth decay, are known as powerful activators of complement system and inflammation. Here, we investigated the role of Gram-negative bacteria-induced complement activation on the pulp progenitor cell recruitment using lipopolysaccharide (LPS), a major component of all Gram-negative bacteria. Our results show that incubating pulp fibroblasts with LPS induced membrane attack complex formation and C5a release in serum-free fibroblast cultures. The produced C5a binds to the pulp progenitor cells’ membrane and induces their migration toward the LPS stimulation chamber, as revealed by the dynamic transwell migration assays. The inhibition of this migration by the C5aR-specific antagonist W54011 indicates that the pulp progenitor migration is mediated by the interaction between C5a and C5aR. Our findings demonstrate, for the first time, a direct interaction between the recruitment of progenitor pulp cells and the activation of complement system generated by pulp fibroblast stimulation with LPS.
Collapse
Affiliation(s)
- F. Chmilewsky
- Aix Marseille Université, CNRS, ISM UMR 7287, Marseille, France
| | - C. Jeanneau
- Aix Marseille Université, CNRS, ISM UMR 7287, Marseille, France
| | - P. Laurent
- Aix Marseille Université, CNRS, ISM UMR 7287, Marseille, France
- APHM, Hôpital Timone, Service d’Odontologie, Marseille, France
| | - I. About
- Aix Marseille Université, CNRS, ISM UMR 7287, Marseille, France
| |
Collapse
|
5
|
Maillard L, Friand V, Suffee N, Hlawaty H, Haddad O, Chmilewsky F, Backhouche S, Desbois E, Oudar O, Letourneur D, Saito N, Ueyama T, Charnaux N, Sutton A. Syndecan-4 intracellular domain orchestrates rantes/CCL5-induced monocyte arrest on endothelial cell monolayer under flow. Atherosclerosis 2014. [DOI: 10.1016/j.atherosclerosis.2014.05.079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
6
|
Chmilewsky F, Jeanneau C, Laurent P, Kirschfink M, About I. C5a induces recruitment of STRO-1 pulp progenitor cells: Possible role in the regenerative process after dentin/pulp injury. Mol Immunol 2013. [DOI: 10.1016/j.molimm.2013.05.043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
7
|
Abstract
It recently became evident that activation of the complement system also contributes to tissue regeneration after infection/injury. The complement-derived fragment C5a induces vascular modifications and attracts cells expressing its receptor (C5aR/CD88) to the site of infection and tissue injury. Besides inflammatory cells, various tissue cells express this receptor. We hypothesized that pulp progenitor cells, being exposed to local complement activation in caries lesions, may respond to C5a via the C5aR. Our work aimed at evaluating the ability of C5a to induce pulp progenitor cell migration that may link complement activation to dentin regeneration. Immunofluorescence analysis of third molar pulp sections showed perivascular localization of the mesenchymal stem cell markers STRO-1 and C5aR. RT-PCR on STRO-1-sorted pulp progenitor cells, co-expressing both STRO-1 and C5aR, revealed high C5aR mRNA levels. Experiments with the C5aR antagonist W54011 revealed that C5a specifically bound to progenitor cells via C5aR, inducing their selective migration toward the C5a gradient. Since we could also demonstrate C5b-9 formation by immunohistochemistry in carious teeth, our findings suggest that, upon local complement activation, C5a induces pulp progenitor cell migration, which may be critical in initiating the regenerative process after dentin/pulp injury.
Collapse
Affiliation(s)
- F Chmilewsky
- Aix-Marseille Université, CNRS, ISM UMR 7287, 13288, Marseille cedex 09, France
| | | | | | | | | |
Collapse
|