Calcium-dependent up-regulation of mitochondrial electron transfer chain gene expressions in human luteinized granulosa cells.
OBJECTIVE
To evaluate the transcription and translation ability of mitochondria in terminally differentiated granulosa cells, these cells were incubated with ionic calcium.


METHODS
Prospective laboratory research.


METHODS
In vitro fertilization laboratory in a university hospital.


METHODS
Granulosa cells were harvested from 50 female patients undergoing IVF.


METHODS
Analysis of mitochondrial gene expression by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) and of mitochondrial-encoded proteins by Western blot.


METHODS
Comparison of the RNA expression levels of genes including cytochrome c oxidase subunit I (COX I), adenosine triphosphate synthase 6 (ATPase 6), flavoprotein, and succinate-ubiquinone oxidoreductase, and protein levels of COX I and flavoprotein in different calcium ion treatment groups.


RESULTS
There were dose-dependent increases in RNA expressions of the four genes analyzed from granulosa cells cultured in a serial concentration of calcium ions. This effect was abolished when cells were preincubated with the extracellular calcium-chelating agent, Ethylene glycol-bis (2-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA). The effect of ionic calcium on both the nuclear- and mitochondrial-encoded subunits also was determined. Expression levels of mitochondrial transcription factor A in RNA significantly increased in granulosa cells that were exposed for 24 and 48 hours to 0.5 and 1 microM A23187.


CONCLUSIONS
The present study is the first report to present calcium-dependent increases in the transcription and translation levels of both nuclear-encoded and mitochondrial-encoded mitochondrial respiratory enzyme subunits and also indicates that mitochondrial transcription factor A is involved in mitochondrial biogenesis.
Au
Heng-Kien
HK
Department of Obstetrics and Gynecology, Taipei Medical University Hospital, Taipei, Taiwan, Republic of China.
Yeh
Tien-Shun
TS
Kao
Shu-Huei
SH
Shih
Chwen-Ming
CM
Hsieh
Rong-Hong
RH
Tzeng
Chii-Ruey
CR
D002118:Calcium / Q000502:physiology*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004579:Electron Transport / Q000187:drug effects / Q000502:physiology; D045222:Electron Transport Chain Complex Proteins / Q000096:biosynthesis* / Q000235:genetics*; D005260:Female; D020869:Gene Expression Profiling; D006107:Granulosa Cells / Q000201:enzymology / Q000378:metabolism*; D006801:Humans; D034461:Luteinization / Q000235:genetics / Q000378:metabolism*; D008928:Mitochondria / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D011446:Prospective Studies; D015854:Up-Regulation / Q000502:physiology*
D045222:Electron Transport Chain Complex Proteins; D002118:Calcium