Molecular Mechanisms in Pathophysiology of Mucopolysaccharidosis and Prospects for Innovative Therapy

Mucopolysaccharidoses (MPSs) are a group of inborn errors of the metabolism caused by a deficiency in the lysosomal enzymes required to break down molecules called glycosaminoglycans (GAGs). These GAGs accumulate over time in various tissues and disrupt multiple biological systems, including catabolism of other substances, autophagy, and mitochondrial function. These pathological changes ultimately increase oxidative stress and activate innate immunity and inflammation. We have described the pathophysiology of MPS and activated inflammation in this paper, starting with accumulating the primary storage materials, GAGs. At the initial stage of GAG accumulation, affected tissues/cells are reversibly affected but progress irreversibly to: (1) disruption of substrate degradation with pathogenic changes in lysosomal function, (2) cellular dysfunction, secondary/tertiary accumulation (toxins such as GM2 or GM3 ganglioside, etc.), and inflammatory process, and (3) progressive tissue/organ damage and cell death (e.g., skeletal dysplasia, CNS impairment, etc.). For current and future treatment, several potential treatments for MPS that can penetrate the blood-brain barrier and bone have been proposed and/or are in clinical trials, including targeting peptides and molecular Trojan horses such as monoclonal antibodies attached to enzymes via receptor-mediated transport. Gene therapy trials with AAV, ex vivo LV, and Sleeping Beauty transposon system for MPS are proposed and/or underway as innovative therapeutic options. In addition, possible immunomodulatory reagents that can suppress MPS symptoms have been summarized in this review.

TNFα induces matrix metalloproteinase-9 expression in monocytic cells through ACSL1/JNK/ERK/NF-kB signaling pathways

Studies have established the association between increased plasma levels of matrix metalloproteinase (MMP)-9 and adipose tissue inflammation. Tumor necrosis factor α (TNFα) was elevated in obesity and is involved in the induction of MMP-9 in monocytic cells. However, the underlying molecular mechanism was incompletely understood. As per our recent report, TNFα mediates inflammatory responses through long-chain acyl-CoA synthetase 1 (ACSL1). Therefore, we further investigated the role of ACSL1 in TNFα-mediated MMP-9 secretion in monocytic cells. THP-1 cells and primary monocytes were used to study MMP-9 expression. mRNA and protein levels of MMP-9 were determined by qRT-PCR and ELISA, respectively. Signaling pathways were studied using Western blotting, inhibitors, and NF-kB/AP1 reporter cells. We found that THP-1 cells and primary human monocytes displayed increased MMP-9 mRNA expression and protein secretion after incubation with TNFα. ACSL1 inhibition using triacsin C significantly reduced the expression of MMP-9 in the THP-1 cells. However, the inhibition of β-oxidation and ceramide biosynthesis did not affect the TNFα-induced MMP-9 production. Using small interfering RNA-mediated ACSL1 knockdown, we further confirmed that TNFα-induced MMP-9 expression/secretion was significantly reduced in ACSL1-deficient cells. TNFα-mediated MMP-9 expression was also significantly reduced by the inhibition of ERK1/ERK2, JNK, and NF-kB. We further observed that TNFα induced phosphorylation of SAPK/JNK (p54/46), ERK1/2 (p44/42 MAPK), and NF-kB p65. ACSL1 inhibition reduced the TNFα-mediated phosphorylation of SAPK/JNK, c-Jun, ERK1/2, and NF-kB. In addition, increased NF-κB/AP-1 activity was inhibited in triacsin C treated cells. Altogether, our findings suggest that ACSL1/JNK/ERK/NF-kB axis plays an important role in the regulation of MMP-9 induced by TNFα in monocytic THP-1 cells.

Establishment of bovine trophoblast stem cells

Here, we report that a chemical cocktail (LCDM: leukemia inhibitory factor [LIF], CHIR99021, dimethinedene maleate [DiM], minocycline hydrochloride), previously developed for extended pluripotent stem cells (EPSCs) in mice and humans, enables de novo derivation and long-term culture of bovine trophoblast stem cells (TSCs). Bovine TSCs retain developmental potency to differentiate into mature trophoblast cells and exhibit transcriptomic and epigenetic (chromatin accessibility and DNA methylome) features characteristic of trophectoderm cells from early bovine embryos. The bovine TSCs established in this study will provide a model to study bovine placentation and early pregnancy failure.

Nuclear Factor-Kappa B-induced miRNA-518a-5p represses trophoblast cell migration and invasion by the Nuclear Factor-Kappa B pathway

Preeclampsia is associated with the insufficient invasion of trophoblasts. NF-κB is a transcription factor in almost all mammalian cells and has been validated to be upregulated in the maternal circulation and placenta of women with preeclampsia. MiR-518a-5p is also overexpressed in pre-eclamptic placenta. The present study was designed to explore whether NF-κB can transcriptionally activate miR-518a-5p and investigate the influences of miR-518a-5p on the viability, apoptosis, migration, and invasion of HTR8/SVneo trophoblast. In situ hybridization and real time polymerase chain reaction were used to reveal miR-518a-5p expression in placenta tissues and HTR8/SVneo cells, respectively. Cell migration and invasion were detected using Transwell inserts. Our findings indicated that NF-κB p52, p50, and p65 can bind to miR-518a-5p gene promoter. MiR-518a-5p further influences the levels of p50 and p65 but not p52. HTR8/SVneo cell viability and apoptosis were not influenced by miR-518a-5p. However, miR-518a-5p represses the migratory/invasive capacities of HTR8/SVneo cell and decreased gelatinolytic activity of MMP2 and MMP9, which was reversed by an NF-κB inhibitor. To sum up, miR-518a-5p is induced by NF-κB and represses trophoblast cell migration and invasion by the NF-κB pathway.

NF-κB and Its Regulators During Pregnancy

The transcriptional factor NF-κB is a nuclear factor involved in both physiological and pathological processes. This factor can control the transcription of more than 400 genes, including cytokines, chemokines, and their modulators, immune and non-immune receptors, proteins involved in antigen presentation and cell adhesion, acute phase and stress response proteins, regulators of apoptosis, growth factors, other transcription factors and their regulators, as well as different enzymes; all these molecules control several biological processes. NF-κB is a tightly regulated molecule that has also been related to apoptosis, cell proliferation, inflammation, and the control of innate and adaptive immune responses during onset of labor, in which it has a crucial role; thus, early activation of this factor may have an adverse effect, by inducing premature termination of pregnancy, with bad outcomes for the mother and the fetus, including product loss. Reviews compiling the different activities of NF-κB have been reported. However, an update regarding NF-κB regulation during pregnancy is lacking. In this work, we aimed to describe the state of the art around NF-κB activity, its regulatory role in pregnancy, and the effect of its dysregulation due to invasion by pathogens like Trichomonas vaginalis and Toxoplasma gondii as examples.

FABP5 enhances malignancies of lower-grade gliomas via canonical activation of NF-κB signaling

Low‐grade gliomas (LGGs) are grade III gliomas based on the WHO classification with significant genetic heterogeneity and clinical properties. Traditional histological classification of gliomas has been challenged by the improvement of molecular stratification; however, the reproducibility and diagnostic accuracy of LGGs classification still remain poor. Herein, we identified fatty acid binding protein 5 (FABP5) as one of the most enriched genes in malignant LGGs and elevated FABP5 revealed severe outcomes in LGGs. Functionally, lentiviral suppression of FABP5 reduced malignant characters including proliferation, cloning formation, immigration, invasion and TMZ resistance, contrarily, the malignancies of LGGs were enhanced by exogenous overexpression of FABP5. Mechanistically, epithelial‐mesenchymal transition (EMT) was correlated to FABP5 expression in LGGs and tumour necrosis factor α (TNFα)‐dependent NF‐κB signalling was involved in this process. Furthermore, FABP5 induced phosphorylation of inhibitor of nuclear factor kappa‐B kinase α (IKKα) thus activated nuclear factor kappa‐B (NF‐κB) signalling. Taken together, our study indicated that FABP5 enhances malignancies of LGGs through canonical activation of NF‐κB signalling, which could be used as individualized prognostic biomarker and potential therapeutic target of LGGs.

An autophagy-related model of 4 key genes for predicting prognosis of patients with laryngeal cancer

Autophagy, a major cause of cancer-related death, is correlated with the pathogenesis of various diseases including cancers. Our study aimed to develop an autophagy-related model for predicting prognosis of patients with laryngeal cancer.We analyzed the correlation between expression profiles of autophagy-related genes (ARGs) and clinical outcomes in 111 laryngeal cancer patients from The Cancer Genome Atlas (TCGA). Afterward, gene functional enrichment analyses of gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were performed to find the major biological attributes. Univariate Cox regression analyses and multivariate Cox regression analyses were performed to screen ARGs whose expression profiles were significantly associated with laryngeal cancer patients overall survival (OS). Furthermore, to provide the doctors and patients with a quantitative method to perform an individualized survival prediction, we constructed a prognostic nomogram.Thirty eight differentially expressed ARGs were screened out in laryngeal cancer patients through the TCGA database. Related functional enrichments may act as tumor-suppressive roles in the tumorigenesis of laryngeal cancer. Subsequently, 4 key prognostic ARGs (IKBKB, ST13, TSC2, and MAP2K7) were identified from all ARGs by the Cox regression model, which significantly correlated with OS in laryngeal cancer. Furthermore, the risk score was constructed, which significantly divided laryngeal cancer patients into high- and low-risk groups. Integrated with clinical characteristics, gender, N and the risk score are very likely associated with patients OS. A prognostic nomogram of ARGs was constructed using the Cox regression model.Our study could provide a valuable prognostic model for predicting the prognosis of laryngeal cancer patients and a new understanding of autophagy in laryngeal cancer.

The effects of extracellular matrix rigidity on 3-dimensional cultures of amnion membrane cells

INTRODUCTION

To determine 3D growth of amnion membrane cells using soft substrate plates of various rigidities.

METHODS

Amnion epithelial (AEC) and mesenchymal cells (AMC) were cultured on 6-well soft substrate plates coated with matrigel and elastomer with rigidities of 0.5, 2, 8, 16, and 64 kPa (n = 3 each). Controls were cells in standard culture conditions. Cell morphology, spheroids' and sheets' formations and viability (bright field microscopy and crystal violet staining), and cellular transitions (vimentin/cytokeratin-18 [CK-18] ratios) were analyzed. A Student t-test was used for statistical analyses.

RESULTS

AECs in substrate rigidities between 2 and 8 kPa formed 3D features (spheroids and sheets) while retaining viability. Two kPa produced spheroids with epithelial characteristics (decrease in vimentin), and 8 kPa favored sheets. Transplantation and culture of AEC sheets with no matrix or elastomers, retained AECs' viability and maintained their epithelial characteristics. Optimum AMC growth was also between 2 and 8 kP A, with predominance of vimentin; however, AMCs did not form 3D structures. Lower and higher rigidities transitioned AMCs into AECs (decrease in vimentin).

DISCUSSION

Matrix rigidities between 2 and 8 kPa produced 3D structures of AECs (spheroids and sheets), resembling amnion membranes' morphology and exhibiting regenerative capacity in utero. Although AMCs grew in similar rigidities, a lack of 3D structures support their dispersed character in the membrane matrix. Extreme rigidities transitioned AMCs into AECs, suggesting that AMCs are transient cells (reservoirs) in the matrix required for remodeling. Compromises in matrix rigidity can cause membrane dysfunction and lead to adverse pregnancy outcomes.

Exploring the multicomponent synergy mechanism of Banxia Xiexin Decoction on irritable bowel syndrome by a systems pharmacology strategy

ETHNOPHARMACOLOGICAL RELEVANCE

Banxia Xiexin Decoction (BXD) is a representative prescription to regulate spleen and stomach in "Treatise on Febrile Diseases", which has been proven effective for the clinical treatment of irritable bowel syndrome (IBS) in the past decades. However, the active principles and molecular mechanisms involved in BXD against IBS are vague yet.

AIM OF THE STUDY

To unfold multicomponent synergy mechanism of BXD on irritable bowel syndrome, this work explored active principles, drug targets and crucial pathways using a systems pharmacology strategy.

MATERIALS AND METHODS

In this study, a systems pharmacology based strategy was applied by the procedures integrating compound database construction, ADME evaluation, target identification, functional annotation, pathway enrichment analysis, network analysis, and molecular docking verification. The 158 compounds from BXD were selected for the screening. The Compound-Target network (C-T) and the Target-Pathway network (T-P) were constructed. The bioinformatics and network topology were employed to systematically reveal multicomponent-target interactions of BXD. The affinity between important ingredients and the kernel targets was validated using molecular mechanics simulation.

RESULTS

The 35 potential important ingredients and the 16 associated kernel targets were identified. 27 crucial pathways, in which the kernel targets participated, could regulate the biological processes, such as synthesis of inflammatory mediators, smooth muscle relaxation and synaptic plasticity, closely related to pathological mechanism of IBS. The cross-talk interactions were revealed between TNF signaling pathway, Dopaminergic synapse and cGMP-PKG signaling pathway, which would exert the synergistic influences on the occurrence and treatment of the IBS. PTGS2, CALM, NOS2, SCN5A, and PRSS1 might become novel drug targets for IBS.

CONCLUSIONS

The study demonstrated that the synergy molecular mechanisms of BXD mainly involved three therapeutic modules including inhibiting inflammatory reaction, maintaining intestinal function and improving psychological regulation via the multicomponent-target interaction networks. It may also provide the promising drug targets and therapeutic agents for the development of new medicines.

Dual Effects of Cell Free Supernatants from Lactobacillus acidophilus and Lactobacillus rhamnosus GG in Regulation of MMP-9 by Up-Regulating TIMP-1 and Down-Regulating CD147 in PMADifferentiated THP-1 Cells

Objective

Recent studies have reported dysregulated expression of matrix metalloproteinases (MMPs), especially MMP-2, MMP-9, tissue inhibitor of metalloproteinase-1, -2 (TIMP-1, TIMP-2), and extracellular matrix metalloproteinase inducer (EMMPRIN/CD147) in activated macrophages of patients with inflammatory diseases. Therefore, MMP-2, MMP-9, and their regulators may represent a new target for treatment of inflammatory diseases. Probiotics, which are comprised of lactic acid bacteria, have the potential to modulate inflammatory responses. In this experimental study, we investigated the anti-inflammatory effects of cell-free supernatants (CFS) from Lactobacillus acidophilus (L. acidophilus) and L. rhamnosus GG (LGG) in phorbol myristate acetate (PMA)-differentiated THP-1 cells.

Materials and Methods

In this experimental study, PMA-differentiated THP-1 cells were treated with CFS from L. acidophilus, LGG and uninoculated bacterial growth media (as a control). The expression of MMP-2, MMP-9, TIMP-1, and TIMP-2 mRNAs were determined using real-time quantitative reverse transcription polymerase chain reaction (RT- PCR). The levels of cellular surface expression of CD147 were assessed by flow cytometry, and the gelatinolytic activity of MMP-2 and MMP-9 were determined by zymography.

Results

Our results showed that CFS from both L. acidophilus and LGG significantly inhibited the gene expression of MMP-9 (P=0.0011 and P=0.0005, respectively), increased the expression of TIMP-1 (P<0.0001), decreased the cell surface expression of CD147 (P=0.0307 and P=0.0054, respectively), and inhibited the gelatinolytic activity of MMP-9 (P=0.0003 and P<0.0001, respectively) in PMA-differentiated THP-1 cells. Although, MMP-2 expression and activity and TIMP-2 expression remained unchanged.

Conclusion

Our results indicate that CFS from L. acidophilus and LGG possess anti-inflammatory properties and can modulate the inflammatory response.

SIRT1 in B[a]P-induced lung tumorigenesis

Benzo[a]pyrene (B[a]P) is a carcinogen in cigarette smoke. We found that B[a]P induced SIRT1 in human bronchial epithelial BEAS-2B cell. SIRT1 was overexpressed in the lung of B[a]P-exposed mice and in human lung cancer biopsies. SIRT1 up-regulated TNF-α and β-catenin and down-regulated the membrane fraction of E-cadherin. In addition, SIRT1 promoted invasion, migration and tumorigenesis of BEAS-2B cells in nude mice upon B[a]P exposure. Thus, SIRT1 is involved in B[a]P-induced transformation associated with activation of the TNF-α/β-catenin axis and is as a potential therapeutic target for lung cancer.

TNFRSF1B Is Associated with ANCA in IBD

The genetic basis of antineutrophil cytoplasmic antibody, an important biomarker of inflammatory bowel disease (IBD), has never been thoroughly examined on a genome-wide scale. In this study, we performed a 2-stage genome-wide association study (GWAS) on antineutrophil cytoplasmic antibody in IBD cases. In the 2959 IBD cases in the discovery stage, we observed an association between a variant in the gene TNFRSF1B with antineutrophil cytoplasmic antibody level (rs5745994, minor allele frequency = 0.028, beta = 18.12, 95% CI, 11.82-24.22, P = 1.89 × 10). This association was replicated in an independent cohort of 419 IBD cases (beta = 16.91, 95% CI, 6.13-27.69, P = 2.38 × 10). With a Q-value of 0.036, we performed a fixed-effect meta-analysis for the association of rs5745994 in both cohorts and observed a stronger association signal (beta = 17.81, 95% CI, 12.36-23.25, P = 8.97 × 10). TNFRSF1B gene codes for tumor necrosis factor (TNF) receptor 2 (TNFR2), thereby we examined the reported TNFRSF1B variant with serum TNFR2 level. We observed a negative association with serum TNFR2 level being 8.23 EU/mL in carriers and 9.12 EU/mL in noncarriers (P = 0.033). This finding indicates the functional role of identified TNFRSF1B variant in IBD serology and may be reflective of the underlying biological mechanisms that determine clinical expression and/or response to certain therapies.

Zinc Prevents Abdominal Aortic Aneurysm Formation by Induction of A20-Mediated Suppression of NF-κB Pathway

Chronic inflammation and degradation of elastin are the main processes in the development of abdominal aortic aneurysm (AAA). Recent studies show that zinc has an anti-inflammatory effect. Based on these, zinc may render effective therapy for the treatment of the AAA. Currently, we want to investigate the effects of zinc on AAA progression and its related molecular mechanism. Rat AAA models were induced by periaortic application of CaCl₂. AAA rats were treated by daily intraperitoneal injection of ZnSO₄ or vehicle alone. The aorta segments were collected at 4 weeks after surgery. The primary rat aortic vascular smooth muscle cells (VSMCs) were stimulated with TNF-α alone or with ZnSO₄ for 3 weeks. The results showed that zinc supplementation significantly suppressed the CaCl₂-induced expansion of the abdominal aortic diameter, as well as a preservation of medial elastin fibers in the aortas. Zinc supplementation also obviously attenuated infiltration of the macrophages and lymphocytes in the aortas. In addition, zinc reduced MMP-2 and MMP-9 production in the aortas. Most importantly, zinc treatment significantly induced A20 expression, along with inhibition of the NF-κB canonical signaling pathway in vitro in VSMCs and in vivo in rat AAA. This study demonstrated, for the first time, that zinc supplementation could prevent the development of rat experimental AAA by induction of A20-mediated inhibition of the NF-κB canonical signaling pathway.

Progesterone, Inflammatory Cytokine (TNF-α), and Oxidative Stress (H2O2) Regulate Progesterone Receptor Membrane Component 1 Expression in Fetal Membrane Cells

Progesterone receptor membrane component 1 (PGRMC1) is an important novel mediator of progesterone (P4) function in fetal membrane cells. We demonstrated previously that PGRMC1 is differentially expressed in fetal membranes among pregnancy subjects and diminished in preterm premature rupture of membrane subjects. In the current study, we aim to elucidate whether PGRMC1 expression is regulated by P4, tumor necrosis factor α (TNF-α), and H2O2 in fetal membrane cells. Primary cultured membrane cells were serum starved for 24 hours followed by treatments of P4, 17 hydroxyprogesterone caproate, and medroxyprogesterone 17 acetate (MPA) at 10(-7) mol/L with ethanol as vehicle control; TNF-α at 10, 20, and 50 ng/mL with phosphate-buffered saline (PBS) as control; and H2O2 at 10 and 100 μmol/L with culture media as control for 24, 48, and 72 hours. The messenger RNA (mRNA) and protein expression of PGRMC1 was quantified using polymerase chain reaction and Western blotting, respectively. We found that PGRMC1 protein expression was regulated by MPA, TNF-α, and H2O2 in a dose-dependent manner. This regulation is also specific to the type of cell (amnion, chorion, or decidua). The upregulation of PGRMC1 by MPA might be mediated through glucocorticoid receptor (GR) demonstrated using amnion and chorion cells model with GR knockdown by specific small interfering RNA transfection. The mRNA expression of PGRMC1 was decreased by H2O2 (100 μmol/L) treatment in amnion cells, which might ultimately result in downregulation of PGRMC1 protein as our data demonstrated. None of other treatments changed PGRMC1 mRNA level in these cells. We conclude that these stimuli act as regulatory factors of PGRMC1 in a cell-specific manner.

A simple feature construction method for predicting upstream/downstream signal flow in human protein-protein interaction networks

Signaling pathways play important roles in understanding the underlying mechanism of cell growth, cell apoptosis, organismal development and pathways-aberrant diseases. Protein-protein interaction (PPI) networks are commonly-used infrastructure to infer signaling pathways. However, PPI networks generally carry no information of upstream/downstream relationship between interacting proteins, which retards our inferring the signal flow of signaling pathways. In this work, we propose a simple feature construction method to train a SVM (support vector machine) classifier to predict PPI upstream/downstream relations. The domain based asymmetric feature representation naturally embodies domain-domain upstream/downstream relations, providing an unconventional avenue to predict the directionality between two objects. Moreover, we propose a semantically interpretable decision function and a macro bag-level performance metric to satisfy the need of two-instance depiction of an interacting protein pair. Experimental results show that the proposed method achieves satisfactory cross validation performance and independent test performance. Lastly, we use the trained model to predict the PPIs in HPRD, Reactome and IntAct. Some predictions have been validated against recent literature.

The Effect of Progestins on Tumor Necrosis Factor α-Induced Matrix Metalloproteinase-9 Activity and Gene Expression in Human Primary Amnion and Chorion Cells In Vitro

BACKGROUND

Current treatment modalities for preventing preterm premature rupture of membranes are limited, but progestins may play a role. Tumor necrosis factor α (TNFα) enhances matrix metalloproteinase-9 (MMP-9) gene expression and activity in fetal membranes, contributing to membrane weakening and rupture. We previously demonstrated that progestins attenuate TNFα-induced MMP-9 activity in a cytotrophoblast cell line. However, whether they have a similar effect in primary amnion and chorion cells of fetal membranes is unknown. In this study, we evaluated the effect of progestins on basal and TNFα-induced MMP-9 activity and gene expression in primary chorion and amnion cells harvested from the fetal membranes of term nonlaboring patients.

METHODS

Primary amnion and chorion cells were isolated from fetal membranes obtained from term uncomplicated nonlaboring patients following elective cesarean delivery (n = 11). Confluent primary amnion and chorion cell cultures were both pretreated with vehicle (control), progesterone (P4), 17α-hydroxyprogesterone caproate (17P), or medroxyprogesterone acetate (MPA) at 10 M concentration for 6 hours followed by stimulation with TNFα at 10 ng/mL for an additional 24 hours. Cell cultures pretreated with the vehicle only served as the unstimulated control and the vehicle stimulated with TNFα served as the stimulated control. Both controls were assigned a value of 100 units. Cell culture medium was harvested for MMP-9 enzymatic activity quantification using gelatin zymography. Total RNA was extracted for quantifying MMP-9 gene expression using real-time quantitative PCR. Basal MMP-9 activity and gene expression data were normalized to the unstimulated control. TNFα-stimulated MMP-9 activity and gene expression were normalized to the stimulated control. The primary outcome was the effect of progestins on TNFα-induced MMP-9 enzymatic activity in term human primary amnion and chorion cells in vitro. Secondary outcomes included the effect of progestin therapy on TNFα-induced MMP-9 gene expression and on basal MMP-9 activity and gene expression in primary amnion and chorion cells in vitro.

RESULTS

Primary cells were harvested from 11 patients. Compared with the unstimulated control, TNFα increased MMP-9 activity (P = 0.005 versus control in primary amnion cells and P < 0.001 versus control in primary chorion cells) and MMP-9 gene expression (P = 0.030 versus control in primary amnion cells, P < 0.001 versus control in primary chorion cells). Compared with the unstimulated controls, MPA, but not P4 or 17P, reduced basal MMP-9 activity [mean difference (95% CI) -49.6 (-81.9, -17.3) units, P = 0.001] and gene expression [mean difference (95% CI) -53.4 (-105.9, -0.9) units, P = 0.045] in primary amnion cells. Compared with the stimulated control, MPA also reduced TNFα-induced MMP-9 activity [mean difference (95% CI) -69.0 (-91.8, -46.3) units, P < 0.001] and gene expression [mean difference (95% CI) -86.0 (-120.7, -51.3) units, P < 0.001] in primary amnion cells. Progestin pretreatment had no significant effect on basal or TNFα-induced MMP-9 activity and gene expression in primary chorion cells.

CONCLUSIONS

The inhibitory effect of MPA on both basal and TNFα-induced MMP-9 activity and gene expression in primary amnion cells demonstrate a possible mechanism by which progestins may prevent fetal membrane weakening leading to preterm premature rupture of membranes.

Placental fractalkine is up-regulated in severe early-onset preeclampsia

The pathogenesis of preeclampsia (PE) includes the release of placental factors into the maternal circulation, inducing an inflammatory environment in the mother. One of the factors may be the proinflammatory chemokine fractalkine, which is expressed in the syncytiotrophoblast of human placenta, from where it is released into the maternal circulation by constitutive shedding. We examined whether placental fractalkine is up-regulated in severe early-onset PE and whether the proinflammatory cytokines tumor necrosis factor (TNF)-α and IL-6 are able to increase the expression of fractalkine. Gene expression analysis, enzyme-linked immunosorbent assay, and immunohistochemistry consistently showed increased fractalkine expression in placentas from severe early-onset PE, compared to gestational age-matched controls. Expression of a disintegrin and metalloproteinases (ADAMs) 10 and 17, which convert transmembrane fractalkine into the soluble form, was significantly increased in these cases. Incubation of first-trimester placental explants with TNF-α provoked a significant increase in fractalkine expression and release of the soluble form, whereas IL-6 had no effect. TNF-α-mediated up-regulation of placental fractalkine was reversed in the presence of the aspirin-derivative salicylate, which impaired activation of NF-κB p65 in TNF-α-treated explants. On the basis of data from placental explants, we suggest that increased maternal TNF-α may up-regulate the expression and release of placental fractalkine, which, in turn, may contribute to an exaggerated systemic inflammatory response in PE.

Tumor necrosis factor-α disruption of brain endothelial cell barrier is mediated through matrix metalloproteinase-9

Traumatic brain injuries cause vascular hyperpermeability. Tumor necrosis factor-α (TNF-α), matrix metalloproteinase-9 (MMP-9), and caspase-3 may be important in these processes but the relationship between them has not been investigated. We hypothesized that TNF-α regulates caspase-3-mediated hyperpermeability and blood brain barrier damage and hyperpermeability directly or indirectly via activation of MMP-9. To test this, rat brain microvascular endothelial cells were treated with TNF-α with or without inhibition of MMP-9. Monolayer permeability was measured, zonula occludens-1 and F-actin configuration were examined, and MMP-9 and caspase-3 activities were quantified. TNF-α increased monolayer permeability, damaged zonula occludens-1, induced filamentous-actin stress fiber formation, and increased both MMP-9 and caspase-3 activities. Inhibition of MMP-9 attenuated these changes. These data highlight a novel link between TNF-α and MMP-9 and show that TNF-α regulated caspase-3-mediated hyperpermeability and vascular damage may be linked to MMP-9 in vitro. These findings augment the understanding of traumatic brain injury and pave the way for improved treatment.

Loss of calreticulin function decreases NFκB activity by stabilizing IκB protein

Transcription factor NFκB is activated by several processes including inflammation, endoplasmic-reticulum (ER) stress, increase in Akt signaling and enhanced proteasomal degradation. Calreticulin (CRT) is an ER Ca(2+)-binding chaperone that regulates many cellular processes. Gene-targeted deletion of CRT has been shown to induce ER stress that is accompanied with a significant increase in the proteasome activity. Loss of CRT function increases the resistance of CRT-deficient (crt-/-) cells to UV- and drug-induced apoptosis. Based on these reports we hypothesized that loss of CRT will activate NFκB signaling thus contributing to enhanced resistance to apoptosis. In contrast to our hypothesis, we observed a significant decrease in the basal transcriptional activity of NFκB in CRT-deficient cells. Treatment with lipopolysaccharide failed to increase the transcriptional activity of NFκB in the crt-/- cells to the same level as in the wt cells. Our data illustrate that the mechanism of decreased NFκB activity in CRT-deficient cells is mediated by a significant increase in IκB protein expression. Furthermore, we showed a significant increase in protein phosphatase 2A activity inhibition which resulted in decreased IκBα protein level in CRT-deficient cells. Based on our data we concluded that loss of CRT increases the stability of IκB protein thus reducing NFκB activity.

Activation of mesenchymal stem cells by macrophages prompts human gastric cancer growth through NF-κB pathway

Accumulating evidence indicate that macrophages activate mesenchymal stem cells (MSCs) to acquire pro-inflammatory phenotype. However, the role of MSCs activated by macrophages in gastric cancer remains largely unknown. In this study, we found that MSCs were activated by macrophages to produce increased levels of inflammatory cytokines. Cell colony formation and transwell migration assays revealed that supernatants from the activated MSCs could promote both gastric epithelial cell and gastric cancer cell proliferation and migration. In addition, the expression of epithelial-mesenchymal transition (EMT), angiogenesis, and stemness-related genes was increased in activated MSCs. The phosphorylated forms of NF-κB, ERK and STAT3 in gastric cells were increased by active MSCs. Inhibition of NF-κB activation by PDTC blocked the effect of activated MSCs on gastric cancer cells. Co-injection of activated MSCs with gastric cancer cells could accelerate gastric cancer growth. Moreover, human peripheral blood monocytes derived macrophages also activated MSCs to prompt gastric cancer cell proliferation and migration. Taken together, our findings suggest that MSCs activated by macrophage acquire pro-inflammatory phenotype and prompt gastric cancer growth in an NF-κB-dependent manner, which provides new evidence for the modulation of MSCs by tumor microenvironment and further insight to the role of stromal cells in gastric carcinogenesis and cancer progression.

Serum amyloid A stimulates cultured endothelial cells to migrate and proliferate: inhibition by the multikinase inhibitor BIBF1120

In the present study, we tested whether serum amyloid A (SAA) protein, an established biomarker of inflammation, also plays a role in stimulating neovascularization. To evaluate this possibility, human carotid artery endothelial (HCtAE) cells were cultured and cellular migration and the proinflammatory and/or thrombotic activity of SAA (0, 1 or 10 μg/mL) on vascular endothelial cells was verified by determining gene regulation relative to control (in the absence of SAA). Exposure of HCtAE cells to SAA increased expression of the transcription factor nuclear factor-κB (NFKB), tumour necrosis factor (TNF) and pro-coagulative tissue factor (F3), and stimulated phosphorylation of the P65 subunit of the NFKB complex. Enhanced production of TNF and NFKB was paralleled by increased vascular endothelial growth factor (VEGF) mRNA and protein expression, as demonstrated by quantitative polymerase chain reaction, western blotting and ELISA. Administration of 10 μg/mL SAA enhanced endothelial cell migration (1.6-fold vs control), stimulated regrowth of HCtAE cells after mechanical injury (~1.2-fold vs control) and increased endothelial tube formation relative to control after 6 h. The SAA-mediated enhancement of endothelial cell migration, proliferation and tube formation were markedly inhibited by pretreatment of HCtAE cells with the multi-angiokinase receptor inhibitor BIBF1120 (100 nmol/L), although SAA-stimulated gene responses for F3 and NFKB were unaffected by 100 nmol/L BIBF1120 pretreatment. Overall, BIBF1120 inhibited the pro-angiogenic activity of SAA on vascular endothelial cells in this experimental model of inflammation.

TNF-α induces matrix metalloproteinase-9-dependent soluble intercellular adhesion molecule-1 release via TRAF2-mediated MAPKs and NF-κB activation in osteoblast-like MC3T3-E1 cells

BACKGROUND

Matrix metalloproteinase-9 (MMP-9) has been shown to be induced by cytokines including TNF-α and may contribute to bone inflammatory diseases. However, the mechanisms underlying MMP-9 expression induced by TNF-α in MC3T3-E1 cells remain unclear.

RESULTS

We applied gelatin zymography, Western blot, RT-PCR, real-time PCR, selective pharmacological inhibitors of transcription (actinomycin D, Act.D), translation (cycloheximide, CHI), c-Src (PP1), MEK1/2 (U0126), p38 MAPK (SB202190), JNK1/2 (SP600125), and NF-κB (Bay11-7082), respective siRNAs transfection, promoter assay, immunofluorescence staining, and ELISA to investigate the MMP-9 expression and soluble ICAM-1 (sICAM-1) release induced by TNF-α in MC3T3-E1 cells. Here we demonstrated that TNF-α-induced MMP-9 expression was attenuated by Act.D, CHI, PP1, U0126, SB202190, SP600125, and Bay11-7082, and by the transfection with siRNAs for ERK2, p38 MAPK, and JNK2. TNF-α-stimulated TNFR1, TRAF2, and c-Src complex formation was revealed by immunoprecipitation and Western blot. Furthermore, TNF-α-stimulated NF-κB phosphorylation and translocation were blocked by Bay11-7082, but not by PP1, U0126, SB202190, or SP600125. TNF-α time-dependently induced MMP-9 promoter activity which was also inhibited by PP1, U0126, SB202190, SP600125, or Bay11-7082. Up-regulation of MMP-9 was associated with the release of sICAM-1 into the cultured medium, which was attenuated by the pretreatment with MMP-2/9i, an MMP-9 inhibitor.

CONCLUSIONS

In this study, we demonstrated that TNF-α up-regulates MMP-9 expression via c-Src, MAPKs, and NF-κB pathways. In addition, TNF-α-induced MMP-9 expression may contribute to the production of sICAM-1 by MC3T3-E1 cells. The interplay between MMP-9 expression and sICAM-1 release may exert an important role in the regulation of bone inflammatory diseases.

Delta-opioid receptors attenuate TNF-α-induced MMP-2 secretion from human ONH astrocytes

PURPOSE

We examined the signaling mechanisms involved in δ-opioid-receptor agonist, SNC-121-mediated attenuation of TNF-α-induced matrix metalloproteinase-2 (MMP-2) secretion from human optic nerve head (ONH) astrocytes.

METHODS

Human ONH astrocytes were treated with SNC-121 (1 μmol/L) for 15 minutes followed by TNF-α (25 ng/mL) treatment for 6 or 24 hours. Cells were pretreated with inhibitors of p38 mitogen-activated protein (MAP) kinase (SB-203580) or NF-κB (Helenalin) prior to TNF-α treatment. Changes in phosphorylation and expression of p38 MAP kinase, IκBα, NF-κB, and MMP-2 were measured by Western blotting. Translocation of NF-κB was determined by immunocytochemistry.

RESULTS

TNF-α treatment increased MMP-2 secretion from ONH astrocytes to 236% ± 17% and 142% ± 8% at 6 and 24 hours, respectively; while SNC-121 treatment reduced MMP-2 secretion to 149% ± 11% and 108% ± 7% at 6 and 24 hours, respectively. The SNC-121-mediated inhibitory response was blocked by the δ-opioid-receptor antagonist naltrindole. TNF-α treatment resulted in a sustained phosphorylation of p38 MAP kinase up to 24 hours (226% ± 15% over control levels), which was reduced to 150% ± 20% by SNC-121 treatment. TNF-α treatment increased the expression of NF-κB to 179% ± 21% and 139% ± 6% at 6 and 24 hours, respectively, which was significantly blocked by SNC-121 treatment. Furthermore, TNF-α-induced MMP-2 secretion was blocked by 100% and 78% in the presence of SB-203580 and Helenalin, respectively.

CONCLUSIONS

Evidence is provided that SNC-121 attenuated TNF-α-induced MMP-2 secretion from ONH astrocytes. Data also supported the idea that p38 MAP kinase and NF-κB played central roles in TNF-α-induced MMP-2 secretion, and both were negatively regulated by SNC-121.

Progesterone receptor membrane component 1 as the mediator of the inhibitory effect of progestins on cytokine-induced matrix metalloproteinase 9 activity in vitro

Progesterone (P4) and the progestin, 17α-hydroxyprogesterone caproate, are clinically used to prevent preterm births (PTBs); however, their mechanism of action remains unclear. Cytokine-induced matrix metalloproteinase 9 (MMP-9) activity plays a key role in preterm premature rupture of the membranes and PTB. We demonstrated that the primary chorion cells and the HTR8/SVneo cells (cytotrophoblast cell line) do not express the classical progesterone receptor (PGR) but instead a novel progesterone receptor, progesterone receptor membrane component 1 (PGRMC1), whose role remains unclear. Using HTR8/SVneo cells in culture, we further demonstrated that 6 hours pretreatment with medroxyprogesterone acetate (MPA) and dexamethasone (Dex) but not P4 or 17α-hydroxyprogesterone hexanoate significantly attenuated tumor necrosis factor α-induced MMP-9 activity after a 24-hour incubation period. The inhibitory effect of MPA, but not Dex, was attenuated when PGRMC1 expression was successfully reduced by PGRMC1 small interfering RNA. Our findings highlight a possible novel role of PGRMC1 in mediating the effects of MPA and in modulating cytokine-induced MMP-9 activity in cytotrophoblast cells in vitro.

Human parvovirus B19 NS1 protein aggravates liver injury in NZB/W F1 mice

Human parvovirus B19 (B19) has been associated with a variety of diseases. However, the influence of B19 viral proteins on hepatic injury in SLE is still obscure. To elucidate the effects of B19 viral proteins on livers in SLE, recombinant B19 NS1, VP1u or VP2 proteins were injected subcutaneously into NZB/W F1 mice, respectively. Significant expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were detected in NZB/W F1 mice receiving B19 NS1 as compared to those mice receiving PBS. Markedly hepatocyte disarray and lymphocyte infiltration were observed in livers from NZB/WF 1 mice receiving B19 NS1 as compared to those mice receiving PBS. Additionally, significant increases of Tumor Necrosis Factor -α (TNF-α), TNF-α receptor, IκB kinase -α (IKK-α), nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor (IκB) and nuclear factor-kappa B (NF-κB) were detected in livers from NZB/W F1 mice receiving B19 NS1 as compared to those mice receiving PBS. Accordingly, significant increases of matrix metalloproteinase-9 (MMP9) and U-plasminogen activator (uPA) were also detected in livers from NZB/W F1 mice receiving B19 NS1 as compared to those mice receiving PBS. Contrarily, no significant variation on livers from NZB/W F1 mice receiving B19 VP1u or VP2 was observed as compared to those mice receiving PBS. These findings firstly demonstrated the aggravated effects of B19 NS1 but not VP1u or VP2 protein on hepatic injury and provide a clue in understanding the role of B19 NS1 on hepatic injury in SLE.

Protein tyrosine phosphatase µ (PTP µ or PTPRM), a negative regulator of proliferation and invasion of breast cancer cells, is associated with disease prognosis

Background

PTPRM has been shown to exhibit homophilic binding and confer cell-cell adhesion in cells including epithelial and cancer cells. The present study investigated the expression of PTPRM in breast cancer and the biological impact of PTPRM on breast cancer cells.

Design

Expression of PTPRM protein and gene transcript was examined in a cohort of breast cancer patients. Knockdown of PTPRM in breast cancer cells was performed using a specific anti-PTPRM transgene. The impact of PTPRM knockdown on breast cancer was evaluated using in vitro cell models.

Results

A significant decrease of PTPRM transcripts was seen in poorly differentiated and moderately differentiated tumours compared with well differentiated tumours. Patients with lower expression of PTPRM had shorter survival compared with those which had a higher level of PTPRM expression. Knockdown of PTPRM increased proliferation, adhesion, invasion and migration of breast cancer cells. Furthermore, knockdown of PTPRM in MDA-MB-231 cells resulted in increased cell migration and invasion via regulation of the tyrosine phosphorylation of ERK and JNK.

Conclusions

Decreased expression of PTPRM in breast cancer is correlated with poor prognosis and inversely correlated with disease free survival. PTPRM coordinated cell migration and invasion through the regulation of tyrosine phosphorylation of ERK and JNK.

Cell-free supernatants from probiotic Lactobacillus casei and Lactobacillus rhamnosus GG decrease colon cancer cell invasion in vitro

Probiotics have been shown to have a preventative role in colorectal carcinogenesis but research concerning their prophylactic potential in the later stages of colorectal cancer, specifically metastasis is limited. This study explored the potential of cell-free supernatants (CFS) from 2 probiotic Lactobacillus sp., Lactobacillus casei and Lactobacillus rhamnosus GG, to inhibit colon cancer cell invasion by influencing matrix metalloproteinase-9 (MMP-9) activity and levels of the tight junction protein zona occludens-1 (ZO-1) in cultured metastatic human colorectal carcinoma cells. HCT-116 cells were treated with CFS from L. casei, L. rhamnosus, or Bacteroides thetaiotaomicron (a gut commensal); or with uninoculated bacterial growth media. Treatment with CFS from both Lactobacillus sp. decreased colorectal cell invasion but treatment with CFS from B. thetaiotaomicron did not. CFS from both Lactobacillus sp. decreased MMP-9 and increased ZO-1 protein levels. L. rhamnosus CFS also lowered MMP-9 activity. To begin elucidating the secreted bacterial factor conveying these responses, Lactobacillus sp. CFS were fractionated into defined molecular weight ranges and cell invasion assessed. Fractionation revealed that the inhibitory activity was contained primarily in the >100 kDa and 50-100 kDa fractions, suggesting the inhibitory compound may be a macromolecule such as a protein, nucleic acid, or a polysaccharide.

Diabetic retinopathy and signaling mechanism for activation of matrix metalloproteinase-9

In the pathogenesis of diabetic retinopathy, H-Ras (a small molecular weight G-protein) and matrix metalloproteinase-9 (MMP9) act as pro-apoptotic, accelerating the apoptosis of retinal capillary cells, a phenomenon that predicts its development and the activation of MMP9 is under the control of H-Ras. The goal of this study is to elucidate the cellular mechanism by which H-Ras activates MMP9 culminating in the development of diabetic retinopathy. Using isolated retinal endothelial cells, the effect of regulation of H-Ras downstream signaling cascade, Raf-1, MEK, and ERK, was investigated on glucose-induced activation of MMP9. In vitro results were confirmed in the retina obtained from diabetic mice manipulated for MMP9 gene, and also in the retinal microvasculature obtained from human donors with diabetic retinopathy. Regulation of Raf-1/MEK/ERK by their specific siRNAs and pharmacologic inhibitors prevented glucose-induced activation of MMP9 in retinal endothelial cells. In MMP9-KO mice, diabetes had no effect on retinal MMP9 activation, and H-Ras/Raf-1/MEK signaling cascade remained normal. Similarly, donors with diabetic retinopathy had increased MMP9 activity in their retinal microvessels, the site of histopathology associated with diabetic retinopathy, and this was accompanied by activated H-Ras signaling pathway (Raf-1/ERK). Collectively, these results suggest that Ras/Raf-1/MEK/ERK cascade has an important role in the activation of retinal MMP9 resulting in the apoptosis of its capillary cells. Understanding the upstream mechanism responsible for the activation of MMP9 should help identify novel molecular targets for future pharmacological interventions to inhibit the development/progression of diabetic retinopathy.

Design of barbiturate-nitrate hybrids that inhibit MMP-9 activity and secretion

We describe a new type of barbiturate-based matrix metalloproteinase (MMP) inhibitor incorporating a nitric oxide (NO) donor/mimetic group (series 1). The compounds were designed to inhibit MMP at enzyme level and to attenuate MMP-9 secretion arising from inflammatory signaling. To detect effects related to the nitrate, we prepared and studied an analogous series of barbiturate C5-alkyl alcohols that were unable to release NO (series 2). Both series inhibited recombinant human MMP-2/9 activity with nanomolar potency. Series 1 consistently inhibited the secretion of MMP-9 from TNFα/IL1β stimulated Caco-2 cells at 10 μM, which could be attributed to NO related effects because the non-nitrate panel did not affect enzyme levels. Several compounds from series 1 (10 μM) inhibited tumor cell invasion but none from the non-nitrate panel did. The work shows that MMP-inhibitory barbiturates are suitable scaffolds for hybrid design, targeting additional facets of MMP pathophysiology, with potential to improve risk-benefit ratios.

Suppression of matrix metalloproteinase-9 expression by andrographolide in human monocytic THP-1 cells via inhibition of NF-κB activation

There is much evidence indicating that human leukemic cells and monocytes/macrophages synthesize, and secrete, several matrix metalloproteinases (MMPs), and participate in the degradation of extracellular matrix components in tissue lesions. In this study, we investigated the effects and mechanisms of andrographolide, extracted from the herb Andrographis paniculata, on human monocytic MMPs expression and activation. Andrographolide (1-50 μM) exhibited concentration-dependent inhibition of MMP-9 activation, induced by either tumor necrosis factor-α (TNF-α), or lipopolysaccharide (LPS), in THP-1cells. In addition, andrographolide did not present an inhibitory effect on MMP-9 enzymatic activity at a concentration of 50 μM. By contrast, enzyme-linked immunosorbent assay (ELISA) showed that andrographolide partially affect TIMP-1 levels. Western blot analysis showed that both TNF-α, and LPS stimulators attenuated MMP-9 protein expression in a concentration-dependent manner. Using reverse transcription polymerase chain reaction (RT-PCR), we found that andrographolide suppressed expression of MMP-9 messenger RNA. Furthermore, we also found that andrographolide could significantly inhibit the degradation of inhibitor-κB-α (IκB-α) induced by TNF-α. We used electrophoretic mobility shift assay and reporter gene detection to show that andrographolide also markedly inhibited NF-κB signaling, anti-translocation and anti-activation. In conclusion, we demonstrate that andrographolide attenuates MMP-9 expression, and its main mechanism might involve the NF-κB signal pathway. These results provide new opportunities for the development of new anti-inflammatory and leukemic therapies.

Expression of extracellular matrix metalloproteinase inducer (EMMPRIN) and its expected roles in the bovine endometrium during gestation

Extracellular matrix metalloproteinase inducer (EMMPRIN) and its induced matrix metalloproteinases (MMPs) play a crucial role in tissue remodeling during the peri-implantation period. However, the role of EMMPRIN in the bovine placenta is still unclear. We have postulated that EMMPRIN might play a regulatory role in trophoblastic cell functions during gestation by itself or through the regulation of MMP expression. In this study, EMMPRIN mRNA was detected in the bovine placentome and interplacentome throughout gestation, and its expression was significantly higher in the cotyledon during late gestation. In situ hybridization showed that EMMPRIN mRNA was expressed in the caruncular epithelium and the cotyledonary epithelium, including binucleate cells. Western blot analysis detected a band representing a protein of approximately 65 kDa in the caruncular and cotyledonary tissues, and the intensity of its expression was increased in both of these tissues during late gestation. The expression levels of MMP-2 and MMP-14 in the bovine placenta were higher during late gestation, as was observed for EMMPRIN. Therefore, EMMPRIN might regulate trophoblastic cell functions, especially those of binucleate cells, through MMP expression in the bovine placenta.

Ranpirnase Interferes with NF-κB Pathway and MMP9 Activity, Inhibiting Malignant Mesothelioma Cell Invasiveness and Xenograft Growth

The ribonuclease ranpirnase (Onconase) has been used empirically to treat malignant mesothelioma (MM) patients, and some of them had prolonged survivals. The aim of this study was to investigate the mechanisms of the therapeutic function of ranpirnase in MM cells. The effects of ranpirnase were studied in vivo and in vitro on 2 MM cell lines (epithelioid REN and sarcomatoid PPM-Mill). We found that ranpirnase was able to inhibit NF-κB nuclear translocation, evaluated by cell fractionation and immunoblotting as well as by immunofluorescence. Also, MMP9 secretion by MM cells was decreased by ranpirnase treatment, as assessed by the reduction of metalloproteinase activity, evaluated by zymography on culture-conditioned media. Ranpirnase induced apoptosis of MM cells in vitro and in vivo, causing a powerful inhibition of MM tumor growth in SCID xenografts, determined by In Vivo Imaging System (IVIS) of tumor cells engineered by lentiviral transduction of the luciferase gene. Finally, mice treated with ranpirnase showed a significantly prolonged survival. Our data provide a mechanistic rationale to explain the beneficial antitumor activity observed in some patients treated with ranpirnase and demonstrate that ranpirnase interferes with the NF-κB pathway, thus influencing MM tumor cell invasiveness and survival. It is hoped that this information will also facilitate the identification of those patients who are more likely to benefit from this drug and will also open a new frontier for the use of this drug in tumor types other than MM.

ADAM17 regulates TNFα production by placental trophoblasts

Increased trophoblast TNFα production is an important component of placental dysfunction in preeclampsia. However, the mechanism of increased TNFα production in the preeclamptic placenta is largely unknown. ADAM17 is a metallopeptidase that functions as a TNFα converting enzyme. In this study, we examined ADAM17 expression in placentas from normal and preeclamptic pregnancies and found increased ADAM17 expression in preeclamptic placentas compared to those from normal placentas, p < 0.05. Since hypoxia/oxidative stress is an underlying pathophysiology in the preeclamptic placenta, we further determined if hypoxia/oxidative stress could modulate ADAM17 expression and subsequently induce TNFα production in placental trophoblasts. Trophoblasts were isolated from normal term placentas and treated with cobalt (II) chloride (CoCl(2)), a hypoxia mimetic agent, at different concentrations. Our results showed that CoCl(2) induced a dose-dependent increase in TNFα production that is associated with enhanced ADAM17 expression. Trophoblast expressions of HO-1 (a sensor of cellular oxidative stress) and caspase-3 (an indicator of apoptosis) in response to CoCl(2) stimulation were also examined. We further found that metallopeptidase inhibitor GM6001 and ADAM17 siRNA could block CoCl(2) induced TNFα production, demonstrating the role of ADAM17 in TNFα production in placental trophoblasts. These results suggest that oxidative stress-induced increased ADAM17 expression could contribute to the increased TNFα production in preeclamptic placentas.