Oestrogen regulates proliferation, osteoblastic differentiation, collagen synthesis and periostin gene expression in human periodontal ligament cells through oestrogen receptor beta.
OBJECTIVE
The present study was designed to examine how oestrogen regulates proliferation, osteoblastic differentiation, collagen synthesis and periostin gene expression in primary human periodontal ligament (hPDL) cells.


METHODS
The short interfering RNA (siRNA) technique was used to inhibit oestrogen receptor beta (ERβ) expression hPDL cells. hPDL cell were isolated and fully characterized. A colorimetric assay was applied for the determination of alkaline phosphatase (ALP). An ELISA kit was used to detect osteocalcin (OCN) levels. Collagen synthesis was determined by measuring the incorporation of L-[3H] praline. RT-PCR was performed to detection of periostin mRNA relative gene expression.


RESULTS
ERβ mRNA was expressed in hPDL cells and significant inhibition of mRNA expression and ERβ mature protein of the ERβ was evident in the siRNA group. At 72h, there was a significant increase in non-transfected hPDL cell proliferation after estradiol stimulation. Addition of 17β-estradiol significantly enhanced ALP activity and production of OCN in non-transfected cells but had no effect on collagen synthesis. A clear increase in periostin mRNA expression levels was observed after incubating hPDL cells with estradiol. In hPDL-siERβ cells, the application of estradiol did not produce any evident differences in periostin mRNA expression


CONCLUSIONS
ERβ may play important roles in oestrogen-induced effects on hPDL cell proliferation, osteoblastic differentiation and expression of key molecules for the functional and structural integrity of the periodontium (i.e. periostin).
Department of Periodontics, Dental School, University of Texas, Health Science Center, San Antonio, TX 78229-3900, USA. mamalis@uthscsa.edu
Anastasios
A
Mamalis
Cleopatra
C
Markopoulou
Anna
A
Lagou
Ioannis
I
Vrotsos
D000328:Adult; D015153:Blotting, Western; D002151:Calorimetry; D015815:Cell Adhesion Molecules / Q000187:drug effects* / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D003094:Collagen / Q000187:drug effects* / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D047629:Estrogen Receptor beta / Q000378:metabolism*; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D015870:Gene Expression; D006801:Humans; D007124:Immunoenzyme Techniques; D049449:Luminescence; D008297:Male; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects*; D010513:Periodontal Ligament / Q000166:cytology* / Q000187:drug effects*; D016012:Poisson Distribution; D034741:RNA, Small Interfering / Q000187:drug effects / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
D015815:Cell Adhesion Molecules; D047629:Estrogen Receptor beta; D004967:Estrogens; C512835:POSTN protein, human; D034741:RNA, Small Interfering; D003094:Collagen