Effect of 17 beta-estradiol on diastrophic dysplasia sulfate transporter activity in otosclerotic bone cell cultures and SaOS-2 cells.
OBJECTIVE
Diastrophic dysplasia sulfate transporter (DTDST) is involved in the regulation of bone turnover, and its activity in otosclerosis has been shown to be abnormally high. Taking into account the role of estrogens in the progression of otosclerosis, the possible effect of estrogens on DTDST was investigated in otosclerotic bone cell cultures and in SaOS-2, a human osteoblastic cell line.


METHODS
Primary bone cell cultures of stapes and external auditory canal (EAC) bone were obtained from 33 patients with otosclerosis and 18 control patients undergoing cerebellopontine angle tumor surgery. These cultures were assessed in parallel with SaOS-2 cells. Estrogen receptors (ERs) were detected using reverse transcriptase polymerase chain reaction. DTDST activity was assessed by sulfate uptake at baseline and after 24 h of incubation with 17 beta-estradiol at concentrations ranging from 10(-12) to 10(-6) M.


RESULTS
Stapes and EAC cultures predominantly expressed mRNA of ER alpha, while ER beta expression was predominant in SaOS-2 cells. In stapes and EAC cultures no modification of DTDST activity was observed with 10(-8) M 17 beta-estradiol. In SaOS-2 cells, DTDST activity was inhibited by 17 beta-estradiol (93.5+/-9.21 vs 83.6+/-8.83 pmol/mg protein/5 min, n=29; mean of differences=10.0+/-3.22, paired t-test, p<0.01).


CONCLUSIONS
DTDST activity is regulated by estrogens in SaOS-2 cells, but not in primary cell cultures from stapes and EAC. This difference in the regulation mechanisms may be related to the type of estrogen receptor expressed.
Imauchi
Yutaka
Y
EMI-U 0112, INSERM, Faculté Xavier Bichat Université Paris 7, Paris, France.
Lainé
Pascale
P
Sterkers
Olivier
O
Ferrary
Evelyne
E
Bozorg Grayeli
Alexis
A
D000328:Adult; D000368:Aged; D027321:Anion Transport Proteins; D001692:Biological Transport; D002352:Carrier Proteins / Q000187:drug effects* / Q000378:metabolism; D002460:Cell Line; D002478:Cells, Cultured; D004424:Ear Canal / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D004958:Estradiol / Q000494:pharmacology*; D004967:Estrogens / Q000494:pharmacology; D005260:Female; D034381:Hearing Loss / Q000209:etiology; D006801:Humans; D008297:Male; D026901:Membrane Transport Proteins; D008875:Middle Aged; D010040:Otosclerosis / Q000150:complications / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D011960:Receptors, Estrogen / Q000235:genetics / Q000378:metabolism; D013199:Stapes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D000076988:Sulfate Transporters; D013431:Sulfates / Q000378:metabolism
D027321:Anion Transport Proteins; D002352:Carrier Proteins; D004967:Estrogens; D026901:Membrane Transport Proteins; D012333:RNA, Messenger; D011960:Receptors, Estrogen; C089651:SLC26A2 protein, human; D000076988:Sulfate Transporters; D013431:Sulfates; D004958:Estradiol