A previous study also reported increased TLR3 staining in the trophoblast, vascular endothelium, and stroma of PE women, however TLR7 and TLR8 staining were not examined. Even though our normotensive P group consisted of women with chorioamnionitis, chronic hypertension, proteinuria without hypertension, or premature rupture of membranes, there were no placentas in this group that had increased levels of TLR3. In the P group, only 3/ 13 placentas for TLR7 and 6/13 placentas for TLR8 exhibited increased levels of these receptors. There was no apparent trend between significant ICG-001 placental TLR activation and clinical indication in the P group. For instance, of the 6 women with chorioamnionitis none had increased levels of TLR3, only 1 had increased levels of TLR7, and 2 for TLR8. Interestingly, 2 women had increased levels for both TLR7 and TLR8 but not TLR3. One woman was a smoker having her 3rd child and the other experienced pre-term rupture of membranes which may have resulted in an acute release of ssRNA. In the PE group, only 4/17 placentas for TLR3 and 2/17 placentas for TLR7 had decreased levels of these receptors while no placentas from PE women had decreased levels of TLR8. These data suggest that significant placental activation of TLR3, TLR7, and TLR8 together is highly associated with PE, but whether these occur prior to the development of PE in women remains to be determined. Including the regulation of spiral artery remodeling and angiogenesis as well as pathogen sensing and immune system signaling. Trophoblasts express numerous TLRs including TLR3, TLR7, and TLR8 and are able to secrete NF-kB-derived proinflammatory chemokines and cytokines. To determine whether TLR3/7/8 activation occurs in trophoblasts, we treated human trophoblasts with agonists for TLR3, TLR7, or TLR7/8. All 3 agonists were able to rapidly increase protein levels of their respective TLR with the peak being 6 hours. Together these findings suggest that persistent TLR3/7/8 activation in trophoblasts may be the cause of the placental dysfunction and inflammation seen in PE. If placental TLR3/7/8 activation is sufficient to cause PE, then treatment of mice with TLR3/7/8 agonists should elicit endothelial dysfunction, proteinuria, and hypertension only if the animal is pregnant. We have previously reported that TLR3 activation with poly I:C in rats and mice causes systemic inflammation in both pregnant and non-pregnant animals, however only pregnant animals developed hypertension, proteinuria, and endothelial dysfunction. In the current study, we confirm these findings. Additionally, 19 placental genes that are significantly altered in poly I:C-treated mice are also significantly altered in mice treated with either a TLR7 or TLR7/8 agonist. The 17 placental genes that were significantly increased in all 3 groups are known to play key roles in the inflammatory response. PE women have elevated levels of interferon-c, tumor necrosis factor-a, IL-17A, IL-6, and CD-40/CD-40 ligand, all genes that were significantly increased in the placentas of TLR3, TLR7, and TLR7/8 agonisttreated mice. The 2 placental genes that were decreased in all 3 groups interestingly have pro-inflammatory chemokine/cytokine roles. However, osteopontin, which increases throughout normal gestation, is also an extracellular matrix protein that plays a role in cell-cell and cell-matrix interactions. It is possible that this decrease in placental osteopontin levels may contribute to the disorganization of placental cells evident in PE. Additionally, osteopontin and IL-18, the other placental gene decreased in TLR3/7/8 agonist-treated mice, both potentiate T helper cell type 1 immune responses.