Human predecidual stromal cells have distinctive characteristics of pericytes: Cell contractility, chemotactic...

Human decidual stromal cells (DSCs) play a key role in maternal-fetal interactions. Precursors of DSCs (preDSCs) localize around vessels in both the endometrium and decidua. Previous studies suggested a relationship between preDSCs and pericytes because these cells share a perivascular location, alpha smooth muscle actin (α-SM actin) expression and the ability to contract under the effects of cytokines.

To further study this relationship, we established 15 human preDSC lines and 3 preDSC clones. The preDSC lines and clones were tested by flow cytometry with a panel of 29 monoclonal antibodies, 14 of which are pericyte markers. The expression of angiogenic factors was determined by RT-PCR, chemotactic activity was studied with the migration assay, and cell contractility was evaluated with the collagen cell contraction assay. Confocal microscopy was used to study decidual sections.

Under the effect of progesterone and cAMP, these lines decidualized in vitro: the cells became rounder and secreted prolactin, a marker of physiological DSC differentiation (decidualization). The antigen phenotype of these preDSC lines and clones was fully compatible with that reported for pericytes. PreDSC lines displayed pericyte characteristics: they expressed angiogenic factors and showed chemotactic and cytokine-induced contractile activity. Confocal microscopic examination of decidual sections revealed the expression of antigens detected in preDSC lines: α-SM actin colocalized with CD146, CD140b, MFG-E8, nestin, and STRO-1 (all of which are pericyte markers) in cells located around the vessels, a distinctive location of preDSCs and pericytes.

Taken together, our results show that preDSCs are pericyte-like cells.