| 1. |
|
|
| 2. |
- Jönsson, Daniel, et al.
(författare)
-
Functional effects of estrogen in the periodontium
- 2007
-
Konferensbidrag (refereegranskat)abstract
- Objectives: Several studies have addressed the association between changes in the female sex hormones estrogen and progesterone levels and changes in parameters of periodontitis. We have previously shown that periodontal ligament cells (PDL cells) express estrogen receptor β (ERβ) but not ERα immunoreactivity. The PDL cells express no immunoreactivity for progesterone receptors, suggesting that this cell-type is not affected by progesterone. Treatment with a physiological concentration of estrogen increases DNA synthesis in human breast cancer cells but has no effect on PDL cell DNA and collagen synthesis. The purpose of this project is to investigate the mechanisms by which estrogen influences structure and function of the periodontal ligament by affecting PDL cell functional properties. Methods: Human PDL cells were obtained from teeth extracted for orthodontic reasons. The cells were cultured from periodontal tissue explants and used in passages 3-5. Subcellular distribution of ERβ was determined by immunogold electron microscopy and confocal imagining using the mitochondrial selective probe MitoTracker and ERβ immunostaining. Expression of mitochondrial protein cytochrome c oxidase subunit I was investigated using Western blotting. The amount of IL-6 was determined by ELISA. Results: Confocal imaging revealed that ERβ immunoreactivity was distributed not only in the nucleus but also in the mitochondria. These results were confirmed using immunogold electron microscopy. Incubation with estrogen down-regulated the mitochondrial enzyme cytochrome c oxidase subunit I expression by about 30%, showing functional significance of mitochondrial ER. Preliminary data show that estrogen attenuates LPS induced IL-6 production in the PDL cells. Conclusion: Our data show that estrogen, preferably via ERβ, affects PDL cell functional properties, suggesting that estrogen and other ER specific ligands may modulate the periodontal tissue structure and function in health and disease.
|
|
| 3. |
- Jönsson, Daniel, et al.
(författare)
-
Functional effects of LPS and estrogen in the periodontium
- 2007
-
Konferensbidrag (refereegranskat)abstract
- Objectives: Several studies have addressed the association between changes in the female sex hormones estrogen levels and changes in parameters of periodontitis. Estrogen affects inflammatory conditions in different parts of the body, such as brain, cardiovascular system and in colon. The effects of LPS in PDL cell inflammatory versus normal physiological conditions are poorly mapped. The aim of the present study was to investigate how LPS affects PDL cell inflammatory versus normal physiological characteristics, and if the effect of LPS was reversed by estrogen. Methods: Human PDL cells were obtained from teeth extracted for orthodontic reasons. The cells were cultured from periodontal tissue explants and used in passages 3-5. The cells were treated with different concentrations of Escherichia coli LPS in the absence or presence of estrogen. Cytokine (IL-6 and CRP) and chemokine (MCP-1) production was measured using ELISA. DNA and collagen synthesis was determined by measuring the incorporation of [3H]thymidine and [3H]proline, respectively. ALP activity was determined colorimetrically. All measurements were normalized to total amount of protein. Results and Conclusions: LPS enhanced the inflammatory characteristics of PDL cells, reflected by enhanced production of IL-6 and MCP-1 but did not effect CRP production. LPS had no effect on collagen and DNA synthesis and alkaline phosphatase activity, however, which suggests that LPS does not affect the physiological properties of PDL cells. Estrogen did not reverse LPS-induced IL-6 and MCP-1 production. The present study suggests that PDL cells in response to LPS via enhanced MCP-1 production contribute to the recruitment of leucocytes to the area of inflammation in periodontitis.
|
|
| 4. |
- Jönsson, Daniel, et al.
(författare)
-
LPS specifically enhances production of MCP-1 and IL-6 in human periodontal ligament cells
- 2007
-
Konferensbidrag (refereegranskat)abstract
- Aim: The aim of the present study was to investigate the effects of LPS on the production of chemokines and cytokines in periodontal ligament cells (PDL cells) and if LPS affects functional characteristics of the cells, such as alkaline phosphatase (ALP) activity, collagen and DNA-synthesis. We also assessed if estrogen modulated the LPS-induced responses. Material and Methods: Explants were obtained from the middle third of root surface from teeth extracted for orthodontic reasons. Cells were allowed to migrate from explants and were used in passages 3-4. Aortic tissue was obtained from NMRI mice. Production of monocyte chemoattractant protein-1 (MCP-1), IL-6 and C-reactive protein (CRP) were assessed using ELISA. Transcriptional activity of macrophage inflammatory protein-2 (MIP-2) gene was examined using real-time RT-PCR. ALP activity was measured using a substrate solution and read colormetrically. Collagen and DNA-synthesis were measured using the radiolabeled isotopes proline and thymidine, respectively. The measurements were corrected to the total amount of protein according to the Lowry method. Results: LPS enhanced the production of MCP-1 and IL-6 in PDL cells in a time and dose dependent manner, but had no effect on CRP production. The effects of LPS in PDL cells were not reversed by estrogen. LPS did not affect ALP activity, collagen and DNA-synthesis in PDL cells. LPS enhanced the transcriptional activity of MIP-2 in smooth muscle cells (SMCs). LPS induced MIP-2 was attenuated by a physiological concentration of estrogen (100nM). Conclusion: LPS enhances the production of MCP-1 and IL-6 in PDL cells in a specific manner. LPS induced MCP-1 production in PDL-cells suggests an important role of PDL cells in recruiting leucocytes to the periodontal ligament. Down-regulation of MIP-2 gene by estrogen suggests that estrogen exerts an anti-inflammatory effect via this mechanism.
|
|
| 5. |
- Nebel, Daniel, et al.
(författare)
-
Genes regulated by estrogen in human PDL cells by whole genome arrays
- 2009
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Background: The periodontal ligament cells (PDL cells) play a key role in the formation of the periodontal ligament but these cells have other functions as well. The PDL cells express estrogen receptors but the functional importance is not known. Estrogen modulates inflammation and our hypothesis is that estrogen protects the periodontium via an anti-inflammatory effect on PDL cells. Aim: To identify genes regulated by estrogen in LPS-treated human PDL cells by whole genome arrays. Materials and methods: PDL cells were obtained from human premolars extracted for orthodontic reasons. The cells were divided into two groups. One group was pre-treated with 17ÿ-estradiol (E2, 100 nM) for 2 h and then with Escherichia coli LPS (500ng/ml) for 24 h. The other group was treated with LPS only. Total RNA was extracted and purified by RNeasy Mini Kit (Qiagen®, USA). A whole genome microarray was performed (Affymetrix®, USA) comparing gene expression in the two groups. The cut-off limit was set to a twofold change. Results and Conclusion: Estrogen caused an up-regulation of 38 genes, while 28 genes were down-regulated. Estrogen regulated genes associated with cell-metabolism and cell-signalling but also genes associated with early the inflammatory response. The functional significance of these findings is now determined by e.g. measuring protein levels with ELISA. We conclude that estrogen regulates gene expression in human PDL cells exposed to LPS.
|
|
