Collagen Type 1 Accelerates Healing of Ruptured Fetal Membranes.

Preterm premature rupture of membranes (pPROM) is a major cause of preterm birth. Recently, extracellular matrix-directed treatment is applied for wound healing. Here, we used a pregnant mouse model to test the efficacy of collagen type 1 gel for healing of the prematurely ruptured fetal membranes. Although injection of PBS into the ruptured fetal membranes resulted in 40% closure, injection of collagen type 1 improved closure rates to 90% within 72 h. Macrophages of the M2 wound healing phenotype were entrapped in the collagen layer. In primary human amnion mesenchymal cells, collagen type 1 gels activated collagen receptor discoidin domain receptor 2 (DDR2) to induce myosin light chain phosphorylation and migration of injured amnion mesenchymal cells. These findings define the mechanisms for matrix-directed therapeutics for pPROM.

Prostaglandin dehydrogenase is a target for successful induction of cervical ripening.

The cervix represents a formidable structural barrier for successful induction of labor. Approximately 10% of pregnancies undergo induction of cervical ripening and labor with prostaglandin (PG) E2 or PGE analogs, often requiring many hours of hospitalization and monitoring. On the other hand, preterm cervical ripening in the second trimester predicts preterm birth. The regulatory mechanisms of this paradoxical function of the cervix are unknown. Here, we show that PGE2 uses cell-specific EP2 receptor-mediated increases in Ca2+ to dephosphorylate and translocate histone deacetylase 4 (HDAC4) to the nucleus for repression of 15-hydroxy prostaglandin dehydrogenase (15-PGDH). The crucial role of 15-PGDH in cervical ripening was confirmed in vivo. Although PGE2 or 15-PGDH inhibitor alone did not alter gestational length, treatment with 15-PGDH inhibitor + PGE2 or metabolism-resistant dimethyl-PGE2 resulted in preterm cervical ripening and delivery in mice. The ability of PGE2 to selectively autoamplify its own synthesis in stromal cells by signaling transcriptional repression of 15-PGDH elucidates long sought-after molecular mechanisms that govern PG action in the cervix. This report details unique mechanisms of action in the cervix and serves as a catalyst for (i) the use of 15-PGDH inhibitors to initiate or amplify low-dose PGE2-mediated cervical ripening or (ii) EP2 receptor antagonists, HDAC4 inhibitors, and 15-PGDH activators to prevent preterm cervical ripening and preterm birth.

Nrf2 Activation Inhibits Effects of Thrombin in Human Amnion Cells and Thrombin-Induced Preterm Birth in Mice.

CONTEXT: Nrf2 is a key transcription factor that modulates cell defense mechanisms against endogenous and exogenous stress. Previously, we reported that thrombin increased matrix metalloproteinases and prostaglandin synthesis in human amnion mesenchymal cells. OBJECTIVE: We sought to determine whether activation of Nrf2 alters the effect of thrombin on prostaglandin synthesis, protease activation, and cytokine release in human amnion. Furthermore, we analyzed the effect of Nrf2 activation on thrombin-induced preterm labor in mice. DESIGN: Primary human amnion mesenchymal cells and pregnant mice were employed to investigate the effect of Nrf2 on thrombin-induced inflammation and preterm birth. SETTING: This was a laboratory-based study using cells and mice. RESULTS: As expected, thrombin increased cyclooxygenase-2, IL-1ß, IL-6, IL-8, and matrix metalloproteinase-1 in amnion mesenchymal cells. Preincubation with Nrf2 activators, diethyl maleate or 15-deoxy-Δ12, 14-prostaglandin J2 (15d-PGJ2), profoundly repressed thrombin-induced gene expression. In addition, Nrf2 activation inhibited thrombin-induced cyclooxygenase-2 protein levels and secretion of prostaglandin E2, IL-1ß, IL-6, IL-8, TNFα, and granulocyte-macrophage colony-stimulating factor in the media. Whereas vehicle and 15d-PGJ2 did not alter gestational length, all pregnant mice treated with thrombin delivered preterm. 15d-PGJ2 delayed thrombin-induced preterm birth significantly. CONCLUSIONS: The results indicate that Nrf2 activation represents a key stress response in amnion mesenchyme cells and in pregnant mice to mitigate the adverse proinflammatory effects of thrombin on the fetal membranes. We suggest, therefore, that pharmacological activation of Nrf2 may prevent the increased risk of preterm premature rupture of the membranes associated with thrombin activation that accompanies subchorionic hemorrhage or bleeding during pregnancy.

SERS and MD simulation studies of a kinase inhibitor demonstrate the emergence of a potential drug discovery tool.

We demonstrate the use of surface-enhanced Raman spectroscopy (SERS) as an excellent tool for identifying the binding site of small molecules on a therapeutically important protein. As an example, we show the specific binding of the common antihypertension drug felodipine to the oncogenic Aurora A kinase protein via hydrogen bonding interactions with Tyr-212 residue to specifically inhibit its activity. Based on SERS studies, molecular docking, molecular dynamics simulation, biochemical assays, and point mutation-based validation, we demonstrate the surface-binding mode of this molecule in two similar hydrophobic pockets in the Aurora A kinase. These binding pockets comprise the same unique hydrophobic patches that may aid in distinguishing human Aurora A versus human Aurora B kinase in vivo. The application of SERS to identify the specific interactions between small molecules and therapeutically important proteins by differentiating competitive and noncompetitive inhibition demonstrates its ability as a complementary technique. We also present felodipine as a specific inhibitor for oncogenic Aurora A kinase. Felodipine retards the rate of tumor progression in a xenografted nude mice model. This study reveals a potential surface pocket that may be useful for developing small molecules by selectively targeting the Aurora family kinases.

Fetal fibronectin signaling induces matrix metalloproteases and cyclooxygenase-2 (COX-2) in amnion cells and preterm birth in mice.

Fetal fibronectin (fFN) in cervical and vaginal secretions has been used as a predictor of preterm delivery. Here, we clarified the pathological function of fFN on cell type-specific matrix metalloproteinases (MMPs) and prostaglandin synthesis in fetal membranes. Treatment of amnion mesenchymal cells with fFN resulted in dramatic increases in MMP-1 and MMP-9 mRNA and enzymatic activity as well as COX-2 mRNA and prostaglandin E(2) synthesis, activating both NFκB and ERK1/2 signaling. Fetal FN-induced increases in MMPs and COX-2 were mediated through its extra domain A and Toll-like receptor 4 expressed in mesenchymal cells. Lipopolysaccharide and TNF-α increased the release of free FN in medium of amnion epithelial cells in culture. Finally, injection of fFN in pregnant mice resulted in preterm birth. Collectively, these results indicate that fFN is not only a marker of preterm delivery but also plays a significant role in the pathogenesis of preterm labor and premature rupture of fetal membranes.

Transforming growth factor ß1 (TGFß1) and progesterone regulate matrix metalloproteinases (MMP) in human endometrial stromal cells.

CONTEXT: Menstruation is preceded by progesterone withdrawal and endometrial matrix remodeling predominantly through induction of matrix metalloproteinases (MMP) and recruitment of invading neutrophils. DESIGN: Using endometrial tissues from women during various phases of the menstrual cycle, we found that MMP2, MMP9, and MMP11 were up-regulated in the late secretory phase/premenstrual phase. Because TGFß-responsive genes were also up-regulated in endometrium during this time, we tested the hypothesis that TGFß1 and progesterone regulate expression of MMP in human endometrial stromal cells (HESC). RESULTS: Treatment of HESC with TGFß1 resulted in marked increases in MMP2 and MMP11 mRNA and pro- and active MMP2 activity. Progesterone inhibited TGFß1-induced stimulation of MMP2 and MMP11 through its nuclear hormone receptors. Interestingly, TGFß1 also decreased progesterone receptor (PR)-A and PR-B in HESC with a more pronounced effect on PR-A. CONCLUSIONS: These data support the hypothesis that TGFß1 has endogenous anti-progestational effects in HESC and that the opposing effects of progesterone and TGFß1 are important in regulation of matrix integrity in human endometrium.