Human uterine decidual macrophages express renin.

Human uterine decidual tissue contains many cell types, including stromal cells, fibroblasts, and macrophages. Earlier studies have shown that decidualized uterine stromal cells express renin, primarily in the form of prorenin. However, the possibility that decidual macrophages, which comprise about 30% of the cells in term decidua, also express renin has not been investigated. To determine whether macrophages express renin, macrophages were isolated from enzymatically dispersed term decidual cells using immunomagnetic beads coupled to antibodies to human leukocyte antigen (HLA)-DR, an antigen present on macrophages, but not other decidual cells. The isolated cells were 92.1% CD14 positive and contained the messenger ribonucleic acids (mRNA) for the interleukin-2 type alpha receptor, but not for PRL, a specific marker of decidualized stromal cells. Immunocytochemical studies of the macrophage-enriched fraction demonstrated that the macrophages contained renin, and reverse transcription-polymerase chain reaction analysis with primers specific for renin indicated that the fraction also contained renin mRNA. Renin was detected in the conditioned medium of cultures of the macrophage-enriched preparations, greater than 90% of which was in the form of prorenin. As anticipated, renin and renin mRNA were also detected in the HLA-DR negative cells, more than 80% of which stained with specific antiserum to PRL. Peripheral mononuclear cells also expressed renin mRNA, as determined by reverse transcription-polymerase chain reaction analysis. These results demonstrate that human decidual macrophages express renin and indicate that renin is expressed by several cell types in decidual tissue.