Single-cell analysis of uterine artery endothelial cells reveals cytokine-induced emergence of specific immunomodulatory subtypes: implications for preeclampsia

While pregnancy is known to be an inflammatory condition, preeclampsia (PE) is associated with higher chemokines and pro-inflammatory cytokines and higher Th1/Th2 and Th17/Treg ratios. Since the uteroplacental space can secrete cytokines, including TNF and IL1B, a common assumption is that the proinflammatory immune cell profile of Th1 and Th17 cells dominating over Th2 and Treg cells begins in that space. To date, a possible role for endothelium in this initiation process has not been considered. Nonetheless, recent publications show that endothelium can become immunomodulatory on exposure to TNF and IL1B, and in systemic hypertension, endothelium has been shown to exist as multiple cell subtypes. We have recently shown that uterine artery endothelial cells from late-pregnant sheep (P-UAEC) treated with TNF alone secrete many of the chemokines and cytokines further elevated in PE subjects. Herein, we show that P-UAEC also exist in multiple subtypes with distinct chemokine and cytokine secretory and immunomodulatory properties. The five subtypes are differentially regulated by TNF-alpha (TNF) and IL1-beta (IL1B), which may favor subtype-specific binding and interaction with distinct classes of Th cells, and an altered ability to respond to Th-secreted cytokines (such as IL17 and IL10). Thus, our data demonstrate the possibility that certain endothelial cell subtypes can be pushed to express immunomodulatory proteins by early exposure to increases in TNF or IL1B of immune cell, trophoblast, and decidual origin. This, in turn, begs the question of whether such endothelial changes could contribute to subsequent immune disturbances seen at the time of clinical presentation.