Molecular mechanism of transcriptional activation of human gelatinase B by proximal promoter

Mitochondrial-targeted antioxidant attenuates preeclampsia-like phenotypes induced by syncytiotrophoblast-specific Gαq signaling

Syncytiotrophoblast stress is theorized to drive development of preeclampsia, but its molecular causes and consequences remain largely undefined. Multiple hormones implicated in preeclampsia signal via the Gαq cascade, leading to the hypothesis that excess Gαq signaling within the syncytiotrophoblast may contribute. First, we present data supporting increased Gαq signaling and antioxidant responses within villous and syncytiotrophoblast samples of human preeclamptic placenta. Second, Gαq was activated in mouse placenta using Cre-lox and DREADD methodologies. Syncytiotrophoblast-restricted Gαq activation caused hypertension, kidney damage, proteinuria, elevated circulating proinflammatory factors, decreased placental vascularization, diminished spiral artery diameter, and augmented responses to mitochondrial-derived superoxide. Administration of the mitochondrial-targeted antioxidant Mitoquinone attenuated maternal proteinuria, lowered circulating inflammatory and anti-angiogenic mediators, and maintained placental vascularization. These data demonstrate a causal relationship between syncytiotrophoblast stress and the development of preeclampsia and identify elevated Gαq signaling and mitochondrial reactive oxygen species as a cause of this stress.

Matrix Metalloproteinases and Their Inhibitors in Pulmonary Fibrosis: EMMPRIN/CD147 Comes into Play

Pulmonary fibrosis (PF) is characterized by aberrant extracellular matrix (ECM) deposition, activation of fibroblasts to myofibroblasts and parenchymal disorganization, which have an impact on the biomechanical traits of the lung. In this context, the balance between matrix metalloproteinases (MMPs) and their tissue inhibitors of metalloproteinases (TIMPs) is lost. Interestingly, several MMPs are overexpressed during PF and exhibit a clear profibrotic role (MMP-2, -3, -8, -11, -12 and -28), but a few are antifibrotic (MMP-19), have both profibrotic and antifibrotic capacity (MMP7), or execute an unclear (MMP-1, -9, -10, -13, -14) or unknown function. TIMPs are also overexpressed in PF; hence, the modulation and function of MMPs and TIMP are more complex than expected. EMMPRIN/CD147 (also known as basigin) is a transmembrane glycoprotein from the immunoglobulin superfamily (IgSF) that was first described to induce MMP activity in fibroblasts. It also interacts with other molecules to execute non-related MMP aactions well-described in cancer progression, migration, and invasion. Emerging evidence strongly suggests that CD147 plays a key role in PF not only by MMP induction but also by stimulating fibroblast myofibroblast transition. In this review, we study the structure and function of MMPs, TIMPs and CD147 in PF and their complex crosstalk between them.

MMP9: A Tough Target for Targeted Therapy for Cancer

Having the capability to proteolyze diverse structural and signaling proteins, matrix metalloproteinase 9 (MMP9), one of the best-studied secretory endopeptidases, has been identified as a crucial mediator of processes closely associated with tumorigenesis, such as the extracellular matrix reorganization, epithelial to mesenchymal transition, cell migration, new blood vessel formation, and immune response. In this review, we present the current state of knowledge on MMP9 and its role in cancer growth in the context of cell adhesion/migration, cancer-related inflammation, and tumor microenvironment formation. We also summarize recent achievements in the development of selective MMP9 inhibitors and the limitations of using them as anticancer drugs.

DACH1 inhibits breast cancer cell invasion and metastasis by down-regulating the transcription of matrix metalloproteinase 9

Human Dachshund homolog 1 (DACH1) is usually defined as a tumor suppressor, which plays an influential role in tumor growth and metastasis in a variety of cancer cells. However, the underlying mechanisms in these process are not yet fully clarified. In this study, DACH1 inhibited the invasion and metastasis of breast cancer cells by decreasing MMP9 expression. Mechanistically, DACH1 represses the transcriptional level of MMP9 by interacting with p65 and c-Jun at the NF-κB and AP-1 binding sites in MMP9 promoter respectively, and the association of DACH1 and p65 promote the recruitment of HDAC1 to the NF-κB binding site in MMP9 promoter, resulting in the reduction of the acetylation level and the transcriptional activity of p65. Accordingly, the level of MMP9 was decreased. In conclusion, we found a new mechanism that DACH1 could inhibit the metastasis of breast cancer cells by inhibiting the expression of MMP9.

GSK-3 Inhibition Modulates Metalloproteases in a Model of Lung Inflammation and Fibrosis

Idiopathic pulmonary fibrosis (IPF) is mainly characterized by aberrant extracellular matrix deposition, consequent to epithelial lung injury and myofibroblast activation, and inflammatory response. Glycogen synthase kinase 3 (GSK-3) is a serine-threonine kinase involved in several pathways, and its inhibition has been already suggested as a therapeutic strategy for IPF patients. There is evidence that GSK-3 is able to induce matrix metalloproteinase (MMP) expression and that its inhibition modulates MMP expression in the tissues. The aim of our study was to investigate the role of GSK-3 and its inhibition in the modulation of MMP-9 and -2 in an in vivo mouse model of lung fibrosis and in vitro using different cell lines exposed to pro-inflammatory or pro-fibrotic stimuli. We found that GSK-3 inhibition down-modulates gene expression and protein levels of MMP-9, MMP-2, and their inhibitors TIMP-1 and TIMP-2 in inflammatory cells harvested from bronchoalveolar lavage fluid (BALF) of mice treated with bleomycin as well as in interstitial alveolar macrophages and cuboidalized epithelial alveolar cells. To the same extent, GSK-3 inhibition blunted the increased MMP-9 and MMP-2 activity induced by pro-fibrotic stimuli in a human lung fibroblast cell line. Moreover, the αSMA protein level, a marker of fibroblast-to-myofibroblast transition involved in fibrosis, was decreased in primary fibroblasts treated with TGFβ following GSK-3 inhibition. Our results confirm the implication of GSK-3 in lung inflammation and fibrosis, suggesting that it might play its role by modulating MMP expression and activity but also pushing fibroblasts toward a myofibroblast phenotype and therefore enhancing extracellular matrix deposition. Thus, its inhibition could represent a possible therapeutic strategy.

Hippocampal blood-brain barrier of methamphetamine self-administering HIV-1 transgenic rats

Combined antiretroviral therapy for HIV infection reduces plasma viral load and prolongs life. However, the brain is a viral reservoir, and pathologies such as cognitive decline and blood-brain barrier (BBB) disruption persist. Methamphetamine abuse is prevalent among HIV-infected individuals. Methamphetamine and HIV toxic proteins can disrupt the BBB, but it is unclear if there exists a common pathway by which HIV proteins and methamphetamine induce BBB damage. Also unknown are the BBB effects imposed by chronic exposure to HIV proteins in the comorbid context of chronic methamphetamine abuse. To evaluate these scenarios, we trained HIV-1 transgenic (Tg) and non-Tg rats to self-administer methamphetamine using a 21-day paradigm that produced an equivalency dose range at the low end of the amounts self-titrated by humans. Markers of BBB integrity were measured for the hippocampus, a brain region involved in cognitive function. Outcomes revealed that tight junction proteins, claudin-5 and occludin, were reduced in Tg rats independent of methamphetamine, and this co-occurred with increased levels of lipopolysaccharide, albumin (indicating barrier breakdown) and matrix metalloproteinase-9 (MMP-9; indicating barrier matrix disruption); reductions in GFAP (indicating astrocytic dysfunction); and microglial activation (indicating inflammation). Evaluations of markers for two signaling pathways that regulate MMP-9 transcription, NF-κB and ERK/∆FosB revealed an overall genotype effect for NF-κB. Methamphetamine did not alter measurements from Tg rats, but in non-Tg rats, methamphetamine reduced occludin and GFAP, and increased MMP-9 and NF-κB. Study outcomes suggest that BBB dysregulation resulting from chronic exposure to HIV-1 proteins or methamphetamine both involve NF-κB/MMP-9.

Autophagy regulates trophoblast invasion by targeting NF-κB activity

Preeclampsia is one of the most serious complications of pregnancy, affecting 5-10% of parturients worldwide. Recent studies have suggested that autophagy is involved in trophoblast invasion and may be associated with defective placentation underlying preeclampsia. We thus aimed to understand the mechanistic link between autophagy and trophoblast invasion. Using the two most commonly used trophoblast cell lines, JEG-3 and HTR-8/SVneo, we inhibited autophagy by ATG5 and beclin-1 shRNA. Conversion of LC3-II was evaluated in ATG5 and beclin-1 knock-down cells in the presence of the lysosomal protease inhibitors E-64d and pepstatin A, to detect the efficiency of autophagy inhibition. Upon autophagy inhibition, we measured cell invasion, activity of NF-κB and related signaling pathways, MMP-2, MMP-9, sFlt-1, and TNF-α levels. Autophagy inhibition increased the invasiveness of these trophoblastic cell lines and increased Akt and NF-κB activity as well as p65 expression. Of note, an NF-κB inhibitor significantly attenuated the trophoblast invasion induced by autophagy inhibition. Autophagy inhibition was also associated with increased MMP-2 and MMP-9 levels and decreased the production of sFlt-1 and TNF-α. Collectively, our results indicate that autophagy regulates trophoblast invasiveness in which the NF-κB pathway and MMP-2, MMP-9, sFlt-1 and TNF-α levels are affected.

Elevated microRNA‑145‑5p increases matrix metalloproteinase‑9 by activating the nuclear factor‑κB pathway in rheumatoid arthritis

The present study explored whether miR‑145‑5p can aggravate the development and progression of rheumatoid arthritis (RA) by regulating the expression of matrix metalloproteinases (MMPs). ELISAs, reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR), and western blotting were used to examine the expression levels of MMP‑1, MMP‑3, MMP‑9, and MMP‑13 in fibroblast‑like synoviocytes (FLS) from patients with RA. Levels of MMP‑1, MMP‑3, MMP‑9, and MMP‑13 were assessed in the right hind ankles of a murine collagen‑induced arthritis (CIA) model by RT‑qPCR and immunohistochemical (IHC) analysis. The effects of activation or inhibition of the nuclear factor‑κB (NF‑κB) pathway on MMPs were evaluated by RT‑qPCR and western blotting. Subcellular localization of NF‑κB p65 was visualized by confocal microscopy. Overexpression of miR‑145‑5p increased the expression of MMP‑3, MMP‑9, and MMP‑13 in RA‑FLS. Moreover, injection of a miR‑145‑5p agomir into mice increased MMP‑3, MMP‑9, and MMP‑13, as demonstrated by RT‑qPCR and IHC analysis. A chemical inhibitor that selectively targets NF‑κB (BAY11‑7082) significantly attenuated MMP‑9 expression, while it did not influence the levels of MMP‑3 and MMP‑13. Immunofluorescence analysis revealed that nuclear localization of p65 was significantly enhanced, indicating that miR‑145‑5p enhances activation of the NF‑κB pathway by promoting p65 nuclear translocation. miR‑145‑5p overexpression also significantly increased phosphorylated p65 levels; however, the levels of IkB‑a were reduced in response to this miRNA. Moreover, our results indicated that miR‑145‑5p aggravated RA progression by activating the NF‑κB pathway, which enhanced secretion of MMP‑9. In conclusion, modulation of miR‑145‑5p expression is potentially useful for the treatment of RA inflammation, by regulating the expression of MMPs, and MMP‑9 in particular, through inhibition of the NF‑κB pathway.

Co-delivery of curcumin and doxorubicin in PEGylated liposomes favored the antineoplastic C26 murine colon carcinoma microenvironment

Our recent studies have demonstrated that the antitumor efficacy of doxorubicin (DOX), administered in long-circulating liposomes (LCL), could be considerably improved after its co-encapsulation with curcumin (CURC). Thus, the question addressed within this article is whether LCL-CURC-DOX can be exploited more efficiently than liposomal DOX for future colorectal cancer therapy. Therefore, we investigated the physicochemical and biological properties of LCL-CURC-DOX and the mechanisms of its antitumor activity in C26 murine colon carcinoma in vivo. Our results proved that the developed nanoformulation based on the co-encapsulation of CURC and DOX met the requirements of a modern drug delivery system for future cancer therapy, demonstrating enhanced antitumor activity on C26 colon carcinoma in vivo. The antitumor efficacy of LCL-CURC-DOX relied on suppressive effects on main protumor processes such as angiogenesis, inflammation, oxidative stress, invasion and resistance to apoptosis, and on the dysregulation of Th1/Th2 cell axis which favored the antineoplastic phenotype of cells in tumor microenvironment (TME). The development of multitargeted strategies aiming at stimulating antitumor effects within the tumor milieu and counteracting the escape mechanisms of cancer cells would be beneficial in the management of colon cancer in the future.

Cell Type-Specific Roles of NF-κB Linking Inflammation and Thrombosis

The transcription factor NF-κB is a central mediator of inflammation with multiple links to thrombotic processes. In this review, we focus on the role of NF-κB signaling in cell types within the vasculature and the circulation that are involved in thrombo-inflammatory processes. All these cells express NF-κB, which mediates important functions in cellular interactions, cell survival and differentiation, as well as expression of cytokines, chemokines, and coagulation factors. Even platelets, as anucleated cells, contain NF-κB family members and their corresponding signaling molecules, which are involved in platelet activation, as well as secondary feedback circuits. The response of endothelial cells to inflammation and NF-κB activation is characterized by the induction of adhesion molecules promoting binding and transmigration of leukocytes, while simultaneously increasing their thrombogenic potential. Paracrine signaling from endothelial cells activates NF-κB in vascular smooth muscle cells and causes a phenotypic switch to a “synthetic” state associated with a decrease in contractile proteins. Monocytes react to inflammatory situations with enforced expression of tissue factor and after differentiation to macrophages with altered polarization. Neutrophils respond with an extension of their life span—and upon full activation they can expel their DNA thereby forming so-called neutrophil extracellular traps (NETs), which exert antibacterial functions, but also induce a strong coagulatory response. This may cause formation of microthrombi that are important for the immobilization of pathogens, a process designated as immunothrombosis. However, deregulation of the complex cellular links between inflammation and thrombosis by unrestrained NET formation or the loss of the endothelial layer due to mechanical rupture or erosion can result in rapid activation and aggregation of platelets and the manifestation of thrombo-inflammatory diseases. Sepsis is an important example of such a disorder caused by a dysregulated host response to infection finally leading to severe coagulopathies. NF-κB is critically involved in these pathophysiological processes as it induces both inflammatory and thrombotic responses.

Glucose starvation induces LKB1-AMPK-mediated MMP-9 expression in cancer cells

Cancer cells utilise the glycolytic pathway to support their rapid growth and proliferation. Since cells in most solid tumours are subjected to severe microenvironmental stresses including low nutrient and oxygen availability, such cancer cells must develop mechanisms to overcome these unfavourable growth conditions by metabolic adaptation. Although the liver kinase B1 (LKB1)-adenosine monophosphate-activated kinase (AMPK) signalling pathway plays a pivotal role in maintaining energy homeostasis under conditions of metabolic stress, the role of LKB1-AMPK signalling in aiding cancer cell survival and in malignant tumours has not yet been fully elucidated. We show that glucose starvation promotes cancer cell invasiveness and migration through LKB1-AMPK-regulated MMP-9 expression. Most intriguingly, triggering the LKB1-AMPK signalling pathway by glucose starvation-induced oxidative stress facilitates selective autophagy, which in turn enhances Keap1 degradation and the subsequent activation of Nrf2. Following this, Nrf2 regulates the transactivation of MMP-9 via Nrf2 binding sites in the promoter region of the MMP-9 gene. These mechanisms also contribute to the suppression of excessive oxidative stress under glucose starvation, and protect against cell death. Our data clearly shows that LKB1-AMPK signalling not only maintains energy and oxidative stress homeostasis, but could also promote cancer progression during metabolic stress conditions by MMP-9 induction.

Sodium nitrite attenuates MMP-9 production by endothelial cells and may explain similar effects of atorvastatin

Imbalanced matrix metalloproteinase (MMP) activity promotes cardiovascular alterations that are attenuated by statins. These drugs exert pleiotropic effects independent of cholesterol concentrations, including upregulation of nitric oxide (NO) formation and MMP downregulation. However, statins also increase tissue concentrations of nitrites, which activate new signaling pathways independent of NO. We examined whether atorvastatin attenuates MMP-9 production by human umbilical vein endothelial cells (HUVEC) stimulated with phorbol 12-myristate 13-acetate (PMA) by mechanisms possibly involving increased nitrite, and whether this effect results of NO formation. We also examined whether such an effect is improved by sildenafil, an inhibitor of phosphodiesterase-5 which potentiates NO-induced increases in cyclic GMP. MMP activity and nitrite concentrations were measured by gelatin zymography and ozone-based reductive chemiluminescence, respectively, in the conditioned medium of HUVECs incubated for 24 h with these drugs. Phospho-NFκB p65 concentrations were measured in cell lysate to assess NFκB activation. Atorvastatin attenuated PMA-induced MMP-9 gelatinolytic activity by mechanisms not involving NO, although it increased nitrite concentrations, whereas sildenafil had no effects. Combining both drugs showed no improved responses compared to atorvastatin alone. While sodium nitrite attenuated MMP-9 production by HUVECs, adding hemoglobin (NO scavenger) did not affect the responses to nitrite. Neither atorvastatin nor nitrite inhibited PMA-induced increases in phospho-NFκB p65 concentrations. These findings show that sodium nitrite attenuates MMP-9 production by endothelial cells and may explain similar effects exerted by atorvastatin. With both drugs, the inhibitory effects on MMP-9 production are not dependent on NO formation or on inhibition of NFκB activation. Our findings may help to elucidate important new nitrite-mediated mechanisms by which statins affect imbalanced MMP activity in a variety of cardiovascular disease.

Implication of thymoquinone as a remedy for polycystic ovary in rat

CONTEXT

Thymoquinone (TQ), an active component of Nigella sativa L. (Ranunculaceae), possesses anti-inflammatory and anti-oxidative properties. Polycystic ovary syndrome exhibits chronic inflammatory behavior, thus might involve nuclear factor kappa B (NF-κB) signaling and related molecular factors.

OBJECTIVE

The objective of the present study is to investigate and validate the effect of TQ in polycystic ovary (PCO) rat.

MATERIALS AND METHODS

To validate the effect of TQ (1 µM/ml), NF-κB activation, COX2 (cyclooxygenase-2) expression and reactive oxygen species (ROS) induction were studied in the KK1 cell line. To evaluate the effect of TQ (2 mg/200 µl olive oil/rat; sc) with an in vivo system, ovulation rate, levels of key ovulation mediators, and ovarian gelatinases activity were compared in superovulated, PCO, and RU486 + TQ-treated Wistar rats.

RESULTS

In vitro studies showed that NF-κB nuclear translocation, COX2, and ROS expression were repressed via TQ supplementation in RU486-treated KK1 cells. Pretreatment of TQ in the PCO rat model induced significant restoration of normal physio-molecular behavior of ovary, such as reduced cysts formation, increased ovulation rate, and normalization of key ovarian factors [like TNF-α-stimulated gene/protein 6, hyaluronan, hyaluronan-binding protein 1, COX2, matrix metalloproteinases (membrane type 1-matrix metalloproteinase, MMP9 and MMP2)], tissue inhibitor of metalloproteinases (TIMP-1 and TIMP-2), and gelatinases (like MMP9 and -2) activity during follicular maturation.

DISCUSSION AND CONCLUSION

Overall, most of the above molecular changes are regulated via NF-κB pathway, thus TQ, due to its modulatory effect on the NF-κB signaling, could elevate normal ovarian phenotype and physiological function in the PCO model, indicating its remarkable potential as a remedy for rat PCO.

Therapeutic effect of Cryptotanshinone on collagen-induced arthritis in rats via inhibiting nuclear factor kappa B signaling pathway

The discovery of new therapeutic drugs with the ability of preventing inflammation and joint destruction with less adverse effects is extremely urgent for rheumatoid arthritis (RA). Cryptotanshinone (CTS), an active component isolated from the root of Salvia miltiorrhiza Bunge, has been reported to have antibacterial and antitumor effects. However, its effects on RA have not been clearly elucidated. Here, we investigated the therapeutic effect of CTS on type II collagen-induced arthritis (CIA) in rats and explored the underlying mechanisms. Our results revealed that CTS treatment efficaciously ameliorated inflammation and joint destruction of rats with CIA. Both in vivo and in vitro studies showed that CTS suppressed the production of proinflammatory cytokines including interleukin 1β, tumor necrosis factor alpha, and interleukin 17α production and downregulated the production and activity of matrix metalloproteinase 9. By receptor activator of nuclear factor kappa B (NF-κB) ligand-induced bone marrow macrophages, we observed that CTS could inhibit osteoclast differentiation, which is critic for joint destruction. Further studies on inflammatory signaling revealed that CTS could inhibit the degradation of inhibitor of NF-κB (IκB) α in vivo and in vitro, prevent the nuclear translocation of NF-κB p65 induced by lipopolysaccharide in a time- and dose-dependent manner. By electrophoretic mobility shift assay and luciferase reporter assay, we found that CTS distinctively inhibited the NF-κB DNA binding activity and NF-κB-dependent luciferase activity. These results indicate that the therapeutic effect of CTS on CIA is accomplished mainly through the inhibition of NF-κB signaling. Our findings provide the evidence to develop CTS as a potential therapeutic agent for patients with RA.

Epigenetic regulation of mmp-9 gene expression

Matrix metalloproteinase 9 (MMP-9) is one of the most studied enzymes in cancer. MMP-9 can cleave proteins of the extracellular matrix and a large number of receptors and growth factors. Accordingly, its expression must be tightly regulated to avoid excessive enzymatic activity, which is associated with disease progression. Although we know that epigenetic mechanisms play a central role in controlling mmp-9 gene expression, predicting how epigenetic drugs could be used to suppress mmp-9 gene expression is not trivial because epigenetic drugs also regulate the expression of key proteins that can tip the balance towards activation or suppression of MMP-9. Here, we review how our understanding of the biology and expression of MMP-9 could be exploited to augment clinical benefits, most notably in terms of the prevention and management of degenerative diseases and cancer.

Nitric oxide attenuates matrix metalloproteinase-9 production by endothelial cells independent of cGMP- or NFκB-mediated mechanisms

Cardiovascular diseases involve critical mechanisms including impaired nitric oxide (NO) levels and abnormal matrix metalloproteinase (MMP) activity. While NO downregulates MMP expression in some cell types, no previous study has examined whether NO downregulates MMP levels in endothelial cells. We hypothesized that NO donors could attenuate MMP-9 production by human umbilical vein endothelial cells (HUVECs) as a result of less NFκB activation or cyclic GMP (cGMP)-mediated mechanisms. We studied the effects of DetaNONOate (10-400 μM) or SNAP (50-400 μM) on phorbol 12-myristate 13-acetate (PMA; 10 nM)-induced increases in MMP-9 activity (by gel zymography) or concentrations (by ELISA) as well as on a tissue inhibitor of MMPs' (TIMP)-1 concentrations (by ELISA) in the conditioned medium of HUVECs incubated for 24 h with these drugs. We also examined whether the irreversible inhibitor of soluble guanylyl cyclase ODQ modified the effects of SNAP or whether 8-bromo-cGMP (a cell-permeable analog of cGMP) influenced PMA-induced effects on MMP-9 expression. Total and phospho-NFκB p65 concentrations were measured in HUVEC lysates to assess NFκB activation. Both NO donors attenuated PMA-induced increases in MMP-9 activity and concentrations without significantly affecting TIMP-1 concentrations. This effect was not modified by ODQ, and 8-bromo-cGMP did not affect MMP-9 concentrations. While PMA increased phospho-NFκB p65 concentrations, SNAP had no influence on this effect. In conclusion, this study shows that NO donors may attenuate imbalanced MMP expression and activity in endothelial cells independent of cGMP- or NFκB-mediated mechanisms. Our results may offer an important pharmacological strategy to approach cardiovascular diseases.

Inhibitory effect of the antimalarial agent artesunate on collagen-induced arthritis in rats through nuclear factor kappa B and mitogen-activated protein kinase signaling pathway

Recent evidence indicates that the antimalarial agent artesunate (ART) has immunomodulatory properties that may be useful for treating rheumatoid arthritis (RA). However, the effects of ART on the RA animal model have not been described. The current study aimed to evaluate the antiarthritic effect of ART and explore the potential mechanism on type II collagen-induced arthritis (CIA) in rats. From the day of arthritis onset, rats were treated daily by gavage with leflunomide (Lef) or ART at a dosage of 10 mg/kg/d or 5 mg/kg/d, respectively, for 16 days. The severity of arthritis and levels of pro- and anti-inflammatory cytokines in site were measured. The expression and activity of metalloproteinase (MMP)-2 and MMP-9 were determined. The activation of nuclear factor kappa B and mitogen-activated protein kinase signaling pathways was investigated in rats with CIA and in Raw264.7 cells. Our results showed that ART treatment significantly attenuated inflammation symptoms and prevented cartilage and bone destruction. ART decreased expression of the proinflammatory cytokines interleukin-1β, tumor necrosis factor-α, and interleukin-17α. Both expression and activity of MMP-9 were efficiently inhibited by ART. ART significantly inhibited the degradation of IκB and activation of extracellular signal-regulated kinase and c-Jun N-terminal kinase in rats with CIA and in lipopolysaccharide-stimulated Raw264.7 cells. The present study demonstrated that ART ameliorated rat CIA. The antiarthritic effect might be achieved by inhibiting the action of proinflammatory cytokines and the activity of MMP-9 via suppression of nuclear factor kappa B and mitogen-activated protein kinase signaling pathway. These results show that ART may be used as an adjuvant therapy for patients with RA.

Identifying the regulative role of NF-κB binding sites within promoter region of human matrix metalloproteinase 9 (mmp-9) by TNF-α induction

Matrix metalloproteinase 9 (MMP-9), a member of MMP family, is involved in many physiological processes, including cardiovascular disease (CVD). Tumor necrosis factor-α (TNF-α) is considered a cytokine with pleiotropic biological capabilities and leads to the process of CVD when TNF-α is abnormally released and stimulates MMP-9 expression and activation. In this study, we investigated the molecular mechanism of TNF-α-regulated MMP-9 expression. The experimental results confirm that TNF-α could upregulate MMP-9 expression in heart myoblast H9c2 cells of rat. To evaluate the MMP-9 regulation at transcriptional level, a DNA fragment of 2.2 kb (-2168/+18) of human mmp-9 promoter region was cloned and constructed in a vector of luciferase reporter gene. The 2.2-kb sequences were identified as having three candidate nuclear factor-κ B (NF-κB) binding sites: NF-κB I (-1418/-1409), NF-κB II (-626/-617), and NF-κB III (-353/-345). A series of reporter vectors with the mutated NF-κB sites of mmp-9 promoter sequences were constructed and transfected into H9c2 cells. The results show that the NF-κB II binding site (-626/-617) within the promoter region of mmp-9 plays a key role in upregulation of mmp-9 expression by TNF-α induction. In addition, we also first identified that the NF-κB I, similar to c-Rel, might be one of the NF-κB families to regulate mmp-9 expression.

Knockdown of stomatin-like protein 2 (STOML2) reduces the invasive ability of glioma cells through inhibition of the NF-κB/MMP-9 pathway

Stomatin-like protein 2 (STOML2), a member of the stomatin family, has been reported to be up-regulated in several types of human cancers. The clinical significance and biological role of STOML2 in gliomas remain largely unknown. Here, we describe the significantly up-regulated expression of STOML2 in glioma cell lines and glioma tissues at both the transcriptional and translational levels. Silencing endogenous STOML2 in glioma cells and primary glioma cells drastically reduced their migratory speed and invasive ability, associated with induction of matrix metallopeptidase 9 (MMP-9). We also demonstrated that knockdown of STOML2 significantly inhibited the transcriptional activity of NF-κB and repressed the expression levels of NF-κB target genes, including MMP-9. A luciferase reporter assay revealed that the impact of STOML2 on MMP-9 expression is NF-κB-dependent. Immunohistochemical analysis showed that the up-regulation of STOML2 was significantly correlated with the WHO histological grade of gliomas (p < 0.001). Patients with higher STOML2 expression levels had an overall shorter survival time, whereas patients with lower expression of STOML2 had a longer survival time. A multivariate analysis revealed that STOML2 expression might be an independent prognostic indicator for the survival of glioma patients. Taken together, our results suggest that overexpression of STOML2 is associated with glioma aggressiveness and may represent an independent prognostic factor for the outcome of glioma patients.

Inhibitory effect of curcumin on motility of human oral squamous carcinoma YD-10B cells via suppression of ERK and NF-kappaB activations

Oral squamous cell carcinomas (OSCCs) are characterized by a marked propensity for local invasion, so the identification of agents inhibiting the onset and progression of OSCC has recently gained interest. Here, we found that curcumin inhibited cell proliferation and motility with decreased activities of matrix metalloproteinase (MMP)-2/9 and decreased mRNA expressions of urokinase-type plasminogen activator (uPA) and its receptor uPAR in the highly invasive human YD-10B OSCC cells. Western blot analysis showed that curcumin inhibited the activation of MAP kinases (especially ERK) and NF-kappaB, which are involved in the transcriptional regulation of proteolytic enzymes. In conclusion, curcumin is one of the strong phytochemicals with antimotility activity of OSCC; the inhibitory effect of curcumin on the motility of YD-10B cells could result from its potential to inhibit the activation of ERK/MAP kinase and NF-kappaB that consequently down-regulate the mRNA expressions and activities of proteolytic enzymes such as uPA and MMP-2/9.

Regulation of matrix metalloproteinase-9 gene expression in MPP+- or 6-OHDA-treated human neuroblastoma SK-N-BE(2)C cells

The aberrant expression of matrix metalloproteinases (MMPs) is known to play an important role in various neurodegenerative diseases, such as Parkinson's disease. In the present study, we found that two well-known dopaminergic neurotoxins, 6-OHDA and MPP(+), induced the expression of MMP-9 in SK-N-BE(2)C human neuroblastoma and Cath.a mouse dopaminergic cell lines. Treatment with MMP-9 inhibitors attenuated the neuronal cell death induced by either 6-OHDA or MPP(+), suggesting that MMP-9 plays an important role in this neurotoxin-mediated cell death. Further mechanistic studies showed that 6-OHDA and MPP(+) increased MMP-9 gene expression by inducing NF-kappaB and AP-1 binding to the MMP-9 promoter. Reactive oxygen species (ROS) appeared to be involved in MMP-9 expression because treatment with the free radical scavenger, N-acetylcysteine (NAC), suppressed both 6-OHDA- and MPP(+)-induced MMP-9 promoter activities. Treatment with several signaling pathway-specific inhibitors revealed that the PI3 kinase inhibitor, LY294002, suppressed 6-OHDA- and MPP(+)-induced MMP-9 promoter activities, whereas the p38 MAPK inhibitor, SB203580, inhibited 6-OHDA-, but not MPP(+)-induced promoter activity. These results collectively suggest that ROS, PI3 kinase, NF-kappaB, and AP-1 are commonly involved in 6-OHDA- and MPP(+)-induced MMP-9 gene expression, and that p38 MAPK is differentially involved. Therefore, controlling MMP-9 expression may have therapeutic potential in Parkinson's disease, which is caused by various neurotoxins, such as 6-OHDA and MPP(+).

Human rhinovirus infection up-regulates MMP-9 production in airway epithelial cells via NF-{kappa}B

Human rhinovirus (HRV) infections up-regulate proinflammatory mediators and growth factors that are associated with exacerbations of inflammatory airway diseases, such as asthma and chronic obstructive pulmonary disease (COPD). Matrix metalloproteinase (MMP)-9 was shown to be increased in the airways of patients with asthma and COPD. We sought to determine whether HRV infection modulated the expression of MMP-9 and its highest-affinity inhibitor, the tissue inhibitor of metalloproteinase (TIMP)-1, and we explored the mechanism by which this modulation occurs. In vitro studies, using RT-PCR, ELISA, zymography, and a fluorescent activity assay, demonstrated that MMP-9 mRNA, protein, and activity were increased upon infection with HRV, whereas TIMP-1 mRNA and protein remained unchanged. These results were verified in vivo, using nasal lavage samples obtained from subjects with confirmed rhinovirus infections. Human rhinovirus infections were shown to up-regulate NF-kappaB, and NF-kappaB has also been reported to play a role in the expression of MMP-9. We therefore investigated the role of NF-kappaB in HRV-induced MMP-9 expression. Using two inhibitors of IkappaBalpha kinase beta, we observed a concentration-dependent decrease in HRV-induced MMP-9 expression. The role of NF-kappaB in HRV-induced MMP-9 expression was further confirmed using MMP-9 promoter luciferase constructs, which demonstrated that an NF-kappaB site at -620/-607 base pairs was necessary for HRV-induced MMP-9 expression. Electrophoretic mobility shift assays and supershift assays confirmed the nuclear translocation and binding of p50/p65 NF-kappaB subunits to an MMP-9-specific NF-kappaB oligonucleotide. This increase in MMP-9 may be a mechanism by which rhinovirus infections contribute to airway inflammation and, potentially, to airway remodeling.

Increased expression and activity of MMP-9 in C-reactive protein- induced human THP-1 mononuclear cells is related to activation of nuclear factor kappa-B

The relation between the expression and activity of MMP-9 in C-reactive protein (CRP)-induced human THP-1 mononuclear cells and the activation of nuclear factor kappa-B (NF-kappaB) was studied to investigate the possible role of CRP in plaque destabilization. Human THP-1 cells were incubated in the presence of CRP at 0 (control group), 25, 50 and 100 microg/mL (CRP groups) for 24 h. In PDTC (a specific NF-kappaB inhibitor) group, the cells were pre-treated with PDTC at 10 micromol/L and then with 100 microg/mL CRP. The conditioned media (CM) and human THP-1 cells in different groups were harvested. MMP-9 expression in CM and human THP-1 cells was measured by ELISA and Western blotting. MMP-9 activity was assessed by fluorogenic substrates. The expression of NF-kappaB inhibitor alpha (IkappaB-alpha) and NF-kappaB P(65) was detected by Western blotting and ELISA respectively. The results showed that CRP increased the expression and activity of MMP-9 in a dose-dependent manner in the human THP-1 cells. Western blotting revealed that IkappaB-alpha expression was decreased in the cells with the concentrations of CRP and ELISA demonstrated that NF-kappaB P65 expression in the CRP-induced cells was increased. After pre-treatment of the cells with PDTC at 10 micromol/L, the decrease in IkappaB-alpha expression and the increase in NF-kappaB P(65) expression in the CRP-induced cells were inhibited, and the expression and activity of MMP-9 were lowered too. It is concluded that increased expression and activity of MMP-9 in CRP-induced human THP-1 cells may be associated with activation of NF-kappaB. Down-regulation of the expression and activity of MMP-9 may be a new treatment alternative for plaque stabilization by inhibiting the NF-kappaB activation.

The ING4 tumor suppressor attenuates NF-kappaB activity at the promoters of target genes

The NF-kappaB family mediates immune and inflammatory responses. In many cancers, NF-kappaB is constitutively activated and induces the expression of genes that facilitate tumorigenesis. ING4 is a tumor suppressor that is absent or mutated in several cancers. Herein, we demonstrate that in human gliomas, NF-kappaB is constitutively activated, ING4 expression is negligible, and NF-kappaB-regulated gene expression is elevated. We demonstrate that an ING4 and NF-kappaB interaction exists but does not prevent NF-kappaB activation, nuclear translocation, or DNA binding. Instead, ING4 and NF-kappaB bind simultaneously at NF-kappaB-regulated promoters, and this binding correlates with reductions in p65 phosphorylation, p300, and the levels of acetylated histones and H3-Me3K4, while enhancing the levels of HDAC-1 at these promoters. Using a knockdown approach, we correlate reductions in ING4 protein levels with increased basal and inducible NF-kappaB target gene expression. Collectively, these data suggest that ING4 may specifically regulate the activity of NF-kappaB molecules that are bound to target gene promoters.

CYR61 is a novel gene associated with temperature-dependent changes in fish metabolism as revealed by cDNA microarray analysis on a medaka Oryzias latipes cell line

A microarray comprising 3,514 cDNAs was constructed from a medaka EST library to elucidate the transcriptional responses associated with temperature shift from 25 to 15 degrees C in a medaka cell line. Microarray analysis revealed that the mRNA levels of 313 clones were significantly different in at least one combination of different incubation periods up to 7 days at a given incubation temperature or between 25 and 15 degrees C at a given incubation period (P < 0.05). These genes are known to be associated with various biological processes including morphogenesis, cell proliferation and response to stress. A number of genes encoding proteins which localize in extracellular areas were apparently up-regulated at 15 degrees C, whereas those localizing in intracellular areas were down-regulated at this temperature. In addition, while a number of genes represented long-term expression changes, only a few responded to short-term inductions. A typical example was CYR61, a multifunctional matricellular signaling modulator, the mRNA levels of which increased after temperature shift from 25 to 15 degrees C in 3 h, and then decreased rapidly to near the original level within 12 h. Another series of analyses by quantitative reverse transcription-PCR revealed that the mRNA levels of CYR61 at 5 degrees C were significantly higher even at 24 h after temperature shift compared to those of the cells successively maintained at 25 degrees C. These analyses suggest that remodeling and reorganizing of extracellular structure of cells are important to offset the low temperature effect and CYR61 is considered to be a novel gene associated with temperature response in poikilotherms.

LZAP, a putative tumor suppressor, selectively inhibits NF-kappaB

LZAP has been reported to inhibit cellular proliferation and clonogenic growth. Here, we report that decreased LZAP expression promoted cellular transformation, xenograft tumor growth, and xenograft tumor vascularity. Loss of LZAP also increased cellular invasion, and MMP-9 expression dependent on NF-kappaB. LZAP directly bound to RelA, impaired serine 536 phosphorylation of RelA, increased HDAC association with RelA, inhibited basal and stimulated NF-kappaB transcriptional activity, and was found at the promoter of selective NF-kappaB-responsive genes. LZAP protein levels were markedly decreased in 32% of primary HNSCCs (n = 28) and decreased LZAP levels in primary HNSCC correlated with increased expression of the NF-kappaB-regulated genes IL-8 and IkappaBalpha. In aggregate, these data support a role of LZAP in NF-kappaB regulation and tumor suppression.

PEA3 is necessary for optimal epidermal growth factor receptor-stimulated matrix metalloproteinase expression and invasion of ovarian tumor cells

Elevated expression of the epidermal growth factor (EGF) receptor (EGFR) is detected in human ovarian tumors and is associated with decreased recurrence-free and overall survival. EGFR activation affects tumor progression in part by promoting tumor invasion through the induction of prometastatic matrix metalloproteinases (MMP). PEA3, an ETS family transcription factor, is elevated in advanced and metastatic ovarian cancer and regulates MMPs in various cell types, therefore, we investigated whether PEA3 is required for the EGFR-dependent induction of MMP mRNA. MMP-9 and MMP-14 mRNA levels were selectively increased in response to EGFR activity in ovarian tumor cells. EGFR activation resulted in nuclear accumulation of PEA3 and direct binding of PEA3, but not the related protein ETS-1, to the endogenous MMP-9 and MMP-14 promoters. Furthermore, PEA3 overexpression was sufficient to induce MMP-9 and MMP-14 mRNA, tumor cell migration, and invasion, suggesting that PEA3 is an important contributor to the metastatic phenotype. Additionally, inhibition of PEA3 expression via short interfering RNA reduced the EGF induction of MMP-9 and MMP-14 gene expression by 92% and 50%, respectively, and impaired EGF-stimulated tumor cell invasion. These results suggest that PEA3 is regulated by EGFR and that the elevated PEA3 expression detected in human ovarian cancer may divert cells to a more invasive phenotype by regulating MMP-9 and MMP-14.

Relaxin-induced matrix metalloproteinase-9 expression is associated with activation of the NF-κB pathway in human THP-1 cells

Matrix metalloproteinases (MMPs) and relaxin (RLX) are reported to play an important role in tissue remodeling and wound repair. When macrophages populate wound sites, they secrete biologically active substances, including MMPs. The transcription factor NF-kappaB is important in MMP gene regulation in macrophage cells. Thus, a monocyte/macrophage cell line, THP-1, was used to study the molecular mechanism of RLX action on MMP-2 and MMP-9 expression. After 24 h incubation with porcine RLX (100 ng/ml), conditioned media (CM) and THP-1 cells were collected. Gelatin zymography demonstrated an increase in pro-MMP-9 activity in response to RLX in CM, and no significant change in pro-MMP-2 expression was observed. Immunoblot analysis also revealed an increase in pro-MMP-9 in CM from RLX-treated THP-1 cells. Gel EMSA showed that NF-kappaB DNA-binding activity was elevated in THP-1 cells treated with RLX for 10 min and reached a peak at 30 min. The NF-kappaB DNA complex was supershifted using antibodies against NF-kappaB subunits p50 and p65. Increased expression of the p50 and p65 NF-kappaB subunits was also detected in THP-1 cells after RLX treatment. Incubation with RLX (90 min) reduced THP-1 expression of the NF-kappaB inhibitor protein, IkappaB-alpha. Using a specific NF-kappaB inhibitor, pyrrolidine dithiocarmate (PDTC) inhibited nuclear binding of NF-kappaB. Pre-exposure to PDTC suppressed pro-MMP-9 activity and protein levels in RLX-treated THP-1 cells. In conclusion, these data suggest that RLX-induced tissue remodeling through increasing MMP-9 expression is dependent on NF-kappaB activation.

FoxO4 regulates tumor necrosis factor alpha-directed smooth muscle cell migration by activating matrix metalloproteinase 9 gene transcription

Phenotypic modulation of vascular smooth muscle cells (SMCs) in the blood vessel wall from a differentiated to a proliferative state during vascular injury and inflammation plays an important role in restenosis and atherosclerosis. Matrix metalloproteinase 9 (MMP9) is a member of the MMP family of proteases, which participate in extracellular matrix degradation and turnover. MMP9 is upregulated and required for SMC migration during the development of restenotic and atherosclerotic lesions. In this study, we show that FoxO4 activates transcription of the MMP9 gene in response to tumor necrosis factor alpha (TNF-alpha) signaling. Inhibition of FoxO4 expression by small interfering RNA or gene knockout reduces the abilities of SMCs to migrate in vitro and inhibit neointimal formation and MMP9 expression in vivo. We further show that both the N-terminal, Sp1-interactive domain and the C-terminal transactivation domain of FoxO4 are required for FoxO4-activated MMP9 transcription. TNF-alpha signaling upregulates nuclear FoxO4. Our studies place FoxO4 in the center of a transcriptional regulatory network that links gene transcription required for SMC remodeling to upstream cytokine signals and implicate FoxO4 as a potential therapeutic target for combating proliferative arterial diseases.

The biochemical origin of pain--proposing a new law of pain: the origin of all pain is inflammation and the inflammatory response. Part 1 of 3--a unifying law of pain

We are proposing a unifying theory or law of pain, which states: the origin of all pain is inflammation and the inflammatory response. The biochemical mediators of inflammation include cytokines, neuropeptides, growth factors and neurotransmitters. Irrespective of the type of pain whether it is acute or chronic pain, peripheral or central pain, nociceptive or neuropathic pain, the underlying origin is inflammation and the inflammatory response. Activation of pain receptors, transmission and modulation of pain signals, neuro plasticity and central sensitization are all one continuum of inflammation and the inflammatory response. Irrespective of the characteristic of the pain, whether it is sharp, dull, aching, burning, stabbing, numbing or tingling, all pain arise from inflammation and the inflammatory response. We are proposing a re-classification and treatment of pain syndromes based upon their inflammatory profile. Treatment of pain syndromes should be based on these principles: 1. Determination of the inflammatory profile of the pain syndrome; 2. Inhibition or suppression of production of the appropriate inflammatory mediators, e.g. with inflammatory mediator blockers or surgical intervention where appropriate; 3. Inhibition or suppression of neuronal afferent and efferent (motor) transmission, e.g. with anti-seizure drugs or local anesthetic blocks; 4. Modulation of neuronal transmission, e.g. with opioid medication. At the L.A. Pain Clinic, we have successfully treated a variety of pain syndromes by utilizing these principles. This theory of the biochemical origin of pain is compatible with, inclusive of, and unifies existing theories and knowledge of the mechanism of pain including the gate control theory, and theories of pre-emptive analgesia, windup and central sensitization.

RRM2 induces NF-kappaB-dependent MMP-9 activation and enhances cellular invasiveness

Ribonucleotide reductase is a dimeric enzyme that catalyzes conversion of ribonucleotide 5'-diphosphates to their 2'-deoxynucleotide forms, a rate-limiting step in the production of 2'-deoxyribonucleoside 5'-triphosphates required for DNA synthesis. The ribonucleotide reductase M2 subunit (RRM2) is a determinant of malignant cellular behavior in a range of human cancers. We examined the effect of RRM2 overexpression on pancreatic adenocarcinoma cellular invasiveness and nuclear factor-kappaB (NF-kappaB) transcription factor activity. RRM2 overexpression increases pancreatic adenocarcinoma cellular invasiveness and MMP-9 expression in a NF-kappaB-dependent manner. RNA interference (RNAi)-mediated silencing of RRM2 expression attenuates cellular invasiveness and NF-kappaB activity. NF-kappaB is a key mediator of the invasive phenotypic changes induced by RRM2 overexpression.

Modulation of autocrine TNF-alpha-stimulated matrix metalloproteinase 9 (MMP-9) expression by mitogen-activated protein kinases in THP-1 monocytic cells

Matrix metalloproteinase 9 (MMP-9) is implicated in various physiological processes by its ability to degrade the extracellular matrix (ECM) and process multiple regulatory proteins. Normally, MMP-9 expression is tightly controlled in cells. Sustained or enhanced MMP-9 secretion, however, has been demonstrated to contribute to the pathophysiology of numerous diseases, including arthritis and tumor progression, rendering this enzyme a major target for clinical interventions. Here we show that constitutive MMP-9 secretion was abrogated in THP-1 monocytic leukemia cells by addition of neutralizing antibodies against tumor necrosis factor alpha (TNF-alpha) or TNF receptor type 1 (TNF-R1), as well as by inhibition of TNF-alpha converting enzyme (TACE). This indicates that MMP-9 production in these cells is maintained by autocrine stimulation, with TNF-alpha acting via TNF-R1. To investigate the intracellular signaling routes involved in MMP-9 gene transcription, cells were treated with different inhibitors of major mitogen-activated protein kinase (MAPK) pathways. Interruption of the extracellular signal-regulated kinase pathway 1/2 (ERK1/2) using PD98059 significantly downregulated constitutive MMP-9 release. In contrast, blockage of p38 kinase activity by addition of SB203580 or SB202190, as well as inhibition of c-Jun N-terminal kinase (JNK) using L-JNK-I1, clearly augmented MMP-9 expression and secretion by an upregulation of ERK1/2 phosphorylation. Moreover, exogenously added TNF-alpha augmented MMP-9 synthesis and secretion in THP-1 cells via enhancement of ERK1/2 activity. Taken together, our results indicate that ERK1/2 activity plays a pivotal role in TNF-alpha-induced MMP-9 production and demonstrate its negative modulation by p38 and JNK activity. These findings suggest ERK1/2 rather than p38 and JNK as a reasonable target to specifically block MMP-9 expression using MAPK inhibitors in therapeutic applications.

Inhibition of invasion and metastasis in oral cancer by targeting urokinase-type plasminogen activator receptor

There have been reports of strong correlations between poor prognosis in various cancers and concomitant expression of urokinase-type plasminogen activator (uPA) and its surface receptor (uPAR). We and others have previously shown that the uPA system plays a significant role in a subset of head and neck squamous cell carcinoma. In the present study, we found that uPAR is required for invasion and metastasis of highly malignant oral cancer cells (OSC-19). Treating OSC-19 cells with antisense oligonucleotides (AS) targeting uPAR resulted in a dramatic decrease of uPAR mRNA expression. Furthermore, pretreatment with AS or siRNA targeting uPAR inhibited progression of OSC-19 cells in experimental models. These results suggest that overexpression of uPAR increases the invasiveness and metastasis of OSC-19 cells, and that uPAR is a promising therapeutic target for regulation of progression of oral cancer.

Lipoic acid in multiple sclerosis: a pilot study

Lipoic acid (LA) is an antioxidant that suppresses and treats an animal model of multiple sclerosis (MS), experimental autoimmune encephalomyelitis. The purpose of this study was to determine the pharmacokinetics (PK), tolerability and effects on matrix metalloproteinase-9 (MMP-9) and soluble intercellular adhesion molecule-1 (sICAMP-1) of oral LA in patients with MS. Thirty-seven MS subjects were randomly assigned to one of four groups: placebo, LA 600 mg twice a day, LA 1200 mg once a day and LA 1200 mg twice a day. Subjects took study capsules for 14 days. We found that subjects taking 1200 mg LA had substantially higher peak serum LA levels than those taking 600 mg and that peak levels varied considerably among subjects. We also found a significant negative correlation between peak serum LA levels and mean changes in serum MMP-9 levels (T = -0.263, P =0.04). There was a significant dose response relationship between LA and mean change in serum sICAM-1 levels (P =0.03). We conclude that oral LA is generally well tolerated and appears capable of reducing serum MMP-9 and sICAM-1 levels. LA may prove useful in treating MS by inhibiting MMP-9 activity and interfering with T-cell migration into the CNS.

A chemotactic peptide from laminin alpha 5 functions as a regulator of inflammatory immune responses via TNF alpha-mediated signaling

Tissue injury triggers inflammatory responses that may result in release of degradation products or exposure of cryptic domains of extracellular matrix components. Previously, we have shown that a cryptic peptide (AQARSAASKVKVSMKF) in the alpha-chain of laminin-10 (alpha5beta1gamma1), a prominent basement membrane component, is chemotactic for both neutrophils (PMNs) and macrophages (Mphis) and induces matrix metalloproteinase-9 (MMP-9) production. To determine whether AQARSAASKVKVSMKF has additional effects on inflammatory cells, we performed microarray analysis of RNA from RAW264.7 Mphis stimulated with AQARSAASKVKVSMKF. Several cytokines and cytokine receptors were increased >3-fold in response to the laminin alpha5 peptide. Among these were TNF-alpha and one of its receptors, the p75 TNFR (TNFR-II), increasing 3.5- and 5.7-fold, respectively. However, the peptide had no effect on p55 TNFR (TNFR-I) expression. Corroborating the microarray data, the protein levels of TNF-alpha and TNFR-II were increased following stimulation of RAW264.7 cells with AQARSAASKVKVSMKF. In addition, we determined that the production of TNF-alpha and TNFR-II in response to AQARSAASKVKVSMKF preceded the production of MMP-9. Furthermore, using primary Mphis from mice deficient in TNFR-I, TNFR-II, or both TNF-alpha receptors (TNFRs), we determined that AQARSAASKVKVSMKF induces MMP-9 expression by Mphis through a pathway triggered by TNFR-II. However, TNF-alpha signaling is not required for AQARSAASKVKVSMKF-induced PMN release of MMP-9 or PMN emigration. These data suggest that interactions of inflammatory cells with basement membrane components may orchestrate immune responses by inducing expression of cytokines, recruitment of inflammatory cells, and release of proteinases.

Disease- and cell-type-specific transcriptional targeting of vectors for osteoarthritis gene therapy: further development of a clinical canine model

OBJECTIVES

The potential for undesirable systemic effects related to constitutive expression of certain therapeutic transgenes may be limited through the development of transcriptionally targeted disease- and cell-type-specific vectors. The objective of this study was to analyse the canine matrix metalloproteinase-9 (MMP-9) promoter and deletion constructs for its ability to drive expression in response to pro-inflammatory cytokines (interleukin-1beta and tumour necrosis factor-alpha).

METHODS

Initial analysis of MMP-9 deletion constructs was made using a luciferase reporter system. The promoter was subsequently engineered to incorporate multiple NF-kappaB sites. In parallel experiments we used the mouse collagen type XI promoter to study cell-type-specific promoter activity in chondrocyte-specific cells (SW1353) and undifferentiated chondroprogenitor cells (ATDC5).

RESULTS

Incorporation of multiple NF-kappaB sites into the MMP-9 promoter enhanced activity while maintaining disease specificity. Further, manipulation of the mouse collagen type XI (mColXI) promoter by the incorporation of SOX9 enhancer sites downstream of a reporter gene, increased gene activity while maintaining cell type specificity.

CONCLUSIONS

Manipulation of promoter and enhancer regions can improve transcriptionally targeted genes. A combination of these systems, in the context of the canine model, has the potential to improve the safety of osteoarthritis gene therapy vectors.

Suppression of experimental abdominal aortic aneurysms in mice by treatment with pyrrolidine dithiocarbamate, an antioxidant inhibitor of nuclear factor-κB

OBJECTIVE

Proinflammatory cytokines and matrix metalloproteinases (MMPs) are prominent mediators of the connective tissue destruction that characterizes abdominal aortic aneurysms (AAAs), and nuclear factor (NF)-kappaB is a cytokine-responsive transcription factor that promotes macrophage MMP expression. The purpose of this study was to determine whether aneurysmal degeneration is influenced by pyrrolidine dithiocarbamate (PDTC), a pharmacologic inhibitor of NF-kappaB.

METHODS

Adult male C57BL/6 mice underwent transient elastase perfusion of the abdominal aorta to induce the development of AAAs. Animals were treated every 48 hours by intraperitoneal injection with either saline (n = 34) or PDTC 20 mg/kg (n = 49). Aortic diameter (AD) measurements were used to determine the extent of aortic dilatation before and immediately after elastase perfusion and again at day 14.

RESULTS

All saline-treated mice developed AAAs associated with mononuclear inflammation and destruction of medial elastin (overall increase in AD, mean +/- SEM, 169.1% +/- 7.5%). In contrast, the incidence of AAAs was only 63% in PDTC-treated mice, with a reduction in the overall increase in AD to 109.8% +/- 4.2% ( P < .0001 vs saline), decreased inflammation, and structural preservation of aortic wall connective tissue. Although aneurysm development in saline-treated mice was associated with a marked increase in aortic tissue NF-kappaB and activator protein 1 DNA-binding activities, both activities were substantially reduced in PDTC-treated animals. PDTC-treated mice also exhibited significantly lower serum and aortic wall concentrations of interleukin 1beta and interleukin 6, as well as lower amounts of aortic wall MMP-9, as compared with saline-treated controls.

CONCLUSIONS

Treatment with PDTC inhibits elastase-induced experimental AAAs in the mouse, along with suppression of aortic wall NF-kappaB and activator protein 1 transcription factor activities, reduced expression of proinflammatory cytokines, and suppression of MMP-9. NF-kappaB is therefore a potentially important therapeutic target for the suppression of aneurysmal degeneration.

CLINICAL RELEVANCE

Development and progression of human AAAs is associated with inflammation and enzymatic degradation of connective tissue proteins. MMP-9 is one of the enzymes involved in aneurysm disease, and its production may be induced in part by activation of the transcription factor NF-kappaB. In this mouse model, treatment with pyrrolidine dithiocarbamate (a pharmacologic inhibitor of NF-kappaB) acted to suppress MMP-9 and aneurysm development. It is hoped that treatment strategies that target NF-kappaB may eventually be shown to suppress the growth of small aortic aneurysms in patients.

Aryl hydrocarbon exposure induces expression of MMP-9 in human prostate cancer cell lines

Although aromatic hydrocarbons have been extensively studied with regard to tumor formation, there has been little investigation into effects of these environmental chemicals on regulation of genes involved in tumor invasion. We investigated effects of three arylhydrocarbons on expression of MMP-9 in PC-3 and DU145 human prostate cancer cells. TCDD exposure lead to dose and time dependent increases in MMP-9 expression. Benzo(a)pyrene and a PAH-containing soot (BDS) also induced this MMP. These hydrocarbons also stimulated MMP-9 protein secretion. Our data demonstrate that aryl hydrocarbons can stimulate the production of MMP-9 in human prostate cancer cells.

RETRACTED: Retrovirally mediated RNA interference targeting the M2 subunit of ribonucleotide reductase: A novel therapeutic strategy in pancreatic cancer

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editors-in-Chief, because an investigation by Harvard Medical School and the Brigham and Women’s Hospital has concluded that Figure 1A is invalid and no underlying research data are available to resolve the discrepancies or validate the reported results.

Activity of the matrix metalloproteinase-9 promoter in human normal and tumor cells

Matrix metalloproteinases (MMPs) belong to a family of proteins essential for those processes involving extracellular matrix degradation, such as embryonic development, morphogenesis, and tissue resorption and remodeling. Some members of this family play a crucial role also in tumor invasion. Most notably, MMP-9 is expressed in invasive tumors, and represents a key protein in brain tumor progression, whereas it is not expressed in adult normal tissues. The expression of the MMP-9, like other members of the family, is transcriptionally regulated. We, therefore, postulated that the MMP-9 promoter could be useful in driving selective expression of exogenous genes in tumor cells. This represents a key feature for gene therapy applications, since currently employed viral promoters induce severe organ toxicity, limiting the clinical benefits. In this study, we investigated the activity of the MMP-9 promoter in driving exogenous gene expression in human cell lines. High levels of reporter gene expression were detected in tumor derived cell lines, whereas the MMP-9 promoter activity in non-tumor cells was negligible. Furthermore, we show that tumor necrosis factor alpha (TNFalpha) is able to enhance considerably the MMP-9 promoter activity only in tumor cells. Since recent studies have indicated that MMP-9 enzymatic activity is detectable in the blood, it would be possible to screen potential responsive patients for a tumor gene therapy approach based on the MMP-9 promoter. Taken together these data suggest that MMP-9 promoter has the characteristics for transcritpionally targeted and inducible gene therapy applications.

Surfactant protein A increases matrix metalloproteinase-9 production by THP-1 cells

Matrix metalloproteinase (MMP)-9 from alveolar macrophages is a major source of elastolytic activity in the lung. It is increased in the bronchoalveolar lavage fluid of patients with emphysema. Although the importance of macrophage-derived elastolytic activity in the pathogenesis of emphysema is well established, questions remain about MMP-9 regulation and activity. Because surfactant protein A (SP-A) is capable of modulating other functions of human monocytic cells, we hypothesized that SP-A may regulate MMP-9 expression. Vitamin D3-differentiated THP-1 cells and peripheral blood mononuclear cells were stimulated in vitro with several concentrations of SP-A for different incubation times. MMP-9 mRNA expression was measured by dot-blot analysis, gelatinolytic activity in the medium was determined by gel zymography, protein expression was determined by ELISA, and a specific MMP-9 activity assay was used to measure the state of activation of this enzyme in the cell supernatants. SP-A induced the expression of MMP-9 in both cell types, the effect was time and dose dependent, and MMP-9 was released in its zymogen form. On the basis of results of neutralizing antibody studies, we believe that SP-A action is mediated through Toll-like receptor-2. Even though the biological meaning of these findings remains to be elucidated, these observations suggest the presence of a novel, locally controlled mechanism by which MMP-9 levels may be regulated in alveolar macrophages. We speculate that SP-A may influence the protease/antiprotease balance in the lungs of patients with quantitative and/or qualitative changes in surfactant constituents favoring an abnormal breakdown of extracellular matrix components.

Regulation of trophoblastic gelatinases by proto-oncogenes

During the first trimester of pregnancy, certain cytotrophoblastic cells (CTB) of anchoring villi invade the underlying decidua. Regulation of this invasive behaviour depends on cytokines and growth factors secreted by decidua and trophoblast, which modulate metalloproteinase (MMP) secretion of CTB. Since MMP-9 expression by CTB is a prerequisite for matrigel invasion and since the promoter region of the MMP-9 gene contains two AP-1 binding sites, we hypothesized, that transient activation of c-jun and c-fos oncogenes (which bind to form AP-1) by tumour necrosis factor (TNFalpha), or the phorbol ester TPA will promote the invasive phenotype of CTB and induce the production of MMP-9.TNFalpha or TPA when added to primary cultures of CTB increase MMP-9 activity and MMP-9 mRNA. This effect is inhibited by cycloheximide indicating the necessity of protein synthesis. TPA or TNFalpha induces also the binding of nuclear proteins (extracted from treated CTB) to a radiolabelled oligonucleotide corresponding to the consensus sequence of the TPA responsive element. Antibodies to Jun and Fos can displace this binding. Transient transfection of antisense mRNA to jun or fos into CTB inhibits the immunoreactivity and gelatinolytic activity of MMP-9. We conclude that AP-1 is necessary but may not be sufficient for transactivation of the MMP-9 gene in human CTB.

Promoter characterization of the novel human matrix metalloproteinase-26 gene: regulation by the T-cell factor-4 implies specific expression of the gene in cancer cells of epithelial origin

A novel matrix metalloproteinase-26 (MMP-26) is known to be specifically expressed in epithelial carcinomas. To facilitate studies of MMP-26 transcriptional regulation, we have cloned and characterized a 1 kb 5'-flanking region of the human MMP-26 gene. Altogether, our findings indicate that the MMP-26 promoter has distinctive structural and functional features among MMP genes. An unusual polyadenylation site proximal to the transcription-factor-binding sites protects transcription of the MMP-26 gene from the upstream promoters and represents a part of the stringent transcriptional regulation of the gene. The MMP-26 gene has a consensus TATA-box and one transcriptional start site located 60 and 35 nucleotides upstream of the translational start site, respectively. The MMP-26 promoter was able to drive luciferase expression in human A549 lung carcinoma, HT1080 fibrosarcoma and HEK293 embryonic kidney cells. The basal transcription efficiency of the MMP-26 promoter is relatively low, thereby explaining the minute expression of the gene in most cells and tissues. When compared with other MMP genes, the MMP-26 promoter contains binding sites for a few transcription factors. Sequential deletion and mutation analysis, and electrophoretic mobility-shift assay have identified the T-cell factor-4 (Tcf-4) motif and the activator protein-1 site as the major regulatory elements of the MMP-26 promoter. Since previous studies have established that the Tcf-4 transcription factor is subjected exclusively to regulation through the beta-catenin/E(epithelial)-cadherin pathway, this implies the specific expression of MMP-26 in cancer cells of epithelial origin.

M. tuberculosis induction of matrix metalloproteinase-9: the role of mannose and receptor-mediated mechanisms

Mycobacterium tuberculosis (Mtb) infection induces the expression of matrix metalloproteinase-9 (MMP-9) in mouse lungs. In cultured human monocytic cells, Mtb bacilli and the cell wall glycolipid lipoarabinomannan (LAM) stimulate high levels of MMP-9 activity. Here, we explore the cellular mechanisms involved in the induction of MMP-9 by Mtb. We show that infection of THP-1 cells with Mtb caused a fivefold increase in MMP-9 mRNA that was associated with increased MMP-9 activity. MMP-9 induction was dependent on microtubule polymerization and protein kinase activation and was associated with increased DNA binding by the transcription factor activator protein-1 (AP-1), which appeared to be important for MMP-9 expression. We then explored the surface molecules potentially involved in Mtb induction of MMP-9, focusing on ligands of the mannose and beta-glucan receptors. MMP-9 activity was induced by the mannose receptor ligands mannan, zymosan, and LAM, whereas the beta-glucan receptor ligand laminarin was not effective. The most active inducers of MMP-9 activity were the particulate ligand zymosan and LAM. Pretreatment of cells with an anti-mannose receptor monoclonal antibody, but not anti-complement receptor 3, decreased the induction of MMP-9 activity by Mtb bacilli. Together, these results suggest that MMP-9 induction by Mtb occurs by receptor-mediated signaling mechanisms involving the binding of mannosylated ligands to mannose receptors, the modulation by cytoskeletal elements such as microtubules, the activation of protein kinases, and transcriptional activation by AP-1.

Transcription factor activation in response to cutaneous injury: role of AP-1 in reepithelialization

Reepithelialization is the process responsible for restoring an intact epidermis following cutaneous injury. A change in the activity of keratinocytes is required for reepithelialization to occur, and this is likely to be regulated by the altered expression of effector genes, mediated by transcription factors. The injury itself provides a stimulus for transcription factor activation either directly due to mechanical stress, or via paracrine mechanisms such as the release of growth factors from damaged cells. Members of the activator protein-1 family, in particular c-fos and c-jun, have been the most widely studied wound-induced transcription factors. The signal transduction pathways linking cellular injury to activator protein-1 stimulation appear to involve an increase in intracellular Ca2+ and activation of mitogen-activated protein kinases. Given that a number of genes involved in the reepithelialization of wounds are regulated by activator protein-1, a distinct role for this transcription factor in reepithelialization is beginning to emerge. This article reviews the evidence for activator protein-1 involvement in reepithelialization, with particular focus on the activation of this transcription factor in response to wounding, the second messenger/kinase pathways involved, and the modulation of downstream genes that have the capacity to regulate keratinocyte function.