Expression of the renin-angiotensin system in a human placental cell line

The renin-angiotensin system (RAS) is present in human placental tissue and participates in regulation of maternal-fetal blood flow during pregnancy. RAS expression in placental tissue is regulated by various hormones and is altered in various disease conditions. An in vitro system is needed to further investigate regulation of the placental RAS. To this end, we studied RAS expression in the human placenta-derived cell line, CRL-7548.

CRL-7548 cells were cultured in plastic plates. Total RNA was extracted, reverse transcribed, and amplified by polymerase chain reaction (PCR) with specific primers. Angiotensin II peptide in the culture media was measured by radioimmunoassay. Renin activity was detected by radioimmunoassay measuring angiotensin I generated. Angiotensin receptor type I was detected by Western blot.

Specific mRNA for angiotensin, renin, angiotensin converting enzyme, and angiotensin receptor type I was detected by real-time PCR. Renin activity was detected in the placental cell lysate, and angiotensin II peptide, the final product of the RAS system, was detected in cell culture media by radioimmunoassay. Angiotensin receptor type I was identified as a 41 kDa protein in cell lysates by Western blot.

These results demonstrate that all necessary components of the classic RAS are expressed in the human placental cell line CRL-7548. This cell line may prove useful as an in vitro system for studying RAS regulation in the placenta.