Glucocorticoid-mediated suppression of cytokine-induced matrix metalloproteinase-9 expression in rat mesangial cells: involvement of nuclear factor-kappaB and Ets transcription factors

The role of matrix metalloproteinase-9 in cardiac remodeling and dysfunction and as a possible blood biomarker in heart failure

Heart failure (HF) is the leading cause of morbidity and mortality in cardiovascular diseases, being responsible for many hospitalizations annually. HF is considered a public health problem with significant economic and social impact, which makes searches essential for strategies that improve the ability to predict and diagnose HF. In this way, biomarkers can help in risk stratification for a more personalized approach to patients with HF. Preclinical and clinical evidence shows the participation of matrix metalloproteinase 9 (MMP-9) in the HF process. In this review, we will demonstrate the critical role that MMP-9 plays in cardiac remodeling and dysfunction. We will also show its importance as a blood biomarker in acute and chronic HF patients.

MMP-2 and MMP-9 levels in plasma are altered and associated with mortality in COVID-19 patients

Respiratory symptoms are one of COVID-19 manifestations, and the metalloproteinases (MMPs) have essential roles in the lung physiology. We sought to characterize the plasmatic levels of matrix metalloproteinase-2 and 9 (MMP-2 and MMP-9) in patients with severe COVID-19 and to investigate an association between plasma MMP-2 and MMP-9 levels and clinical outcomes and mortality. MMP-2 and MMP-9 levels in plasma from patients with COVID-19 treated in the ICU (COVID-19 group) and Control patients were measured with the zymography. The study groups were matched for age, sex, hypertension, diabetes, BMI, and obesity profile. MMP-2 levels were lower and MMP-9 levels were higher in a COVID-19 group (p < 0.0001) compared to Controls. MMP-9 levels in COVID-19 patients were not affected by comorbidity such as hypertension or obesity. MMP-2 levels were affected by hypertension (p < 0.05), but unaffected by obesity status. Notably, hypertensive COVID-19 patients had higher MMP-2 levels compared to the non-hypertensive COVID-19 group, albeit still lower than Controls (p < 0.05). No association between MMP-2 and MMP-9 plasmatic levels and corticosteroid treatment or acute kidney injury was found in COVID-19 patients. The survival analysis showed that COVID-19 mortality was associated with increased MMP-2 and MMP-9 levels. Age, hypertension, BMI, and MMP-2 and MMP-9 were better predictors of mortality during hospitalization than SAPS3 and SOFA scores at hospital admission. In conclusion, a significant association between MMP-2 and MMP-9 levels and COVID-19 was found. Notably, MMP-2 and MMP-9 levels predicted the risk of in-hospital death suggesting possible pathophysiologic and prognostic roles.

Small leucine zipper protein promotes the metastasis of castration-resistant prostate cancer through transcriptional regulation of matrix metalloproteinase-13

Matrix metalloproteinases (MMPs) function as central modulators of tissue remodeling. Abnormal expression and altered activity of MMPs result in excessive extracellular matrix degradation and increased tumor metastasis in various cancers. Small leucine zipper protein (sLZIP), belonging to the leucine zipper transcription factor family, functions as a transcriptional regulator of genes involved in various cellular processes. However, its role in MMP expression and castration-resistant prostate cancer (CRPC) metastasis remains unclear. In this study, we investigated the role of sLZIP in MMP-13 expression and its involvement in CRPC metastasis. sLZIP increased MMP-13 transcription by directly binding to its promoter in CRPC cells. We found that the expression levels of GR, which represses MMP transcription, were elevated in CRPC cells. However, sLZIP suppressed the inhibitory effect of GR and enhanced the secretion of MMP-13 in CRPC cells. sLZIP promoted cell migration and invasion; however, a specific MMP-13 inhibitor blocked sLZIP-induced cell motility. Depletion of sLZIP using the CRISPR/Cas9 system downregulated MMP-13 mRNA expression in PC3 cells. Mice injected with sLZIP-depleted PC3 cells showed significantly reduced metastatic tumor volume in the lung compared to mice injected with control PC3 cells. Our findings suggest that sLZIP plays an important role in MMP-13 induction and CRPC metastasis. Therefore, sLZIP inhibition could be a novel therapeutic strategy for metastatic GR-enriched CRPC.

Concomitant use of dexamethasone and tetracyclines: a potential therapeutic option for the management of severe COVID-19 infection?

Introduction: The global coronavirus disease-2019 (COVID-19) pandemic has posed a critical challenge to the research community as well as to the healthcare systems. Severe COVID-19 patients are at a higher risk of developing serious complications and mortality. There is a dire need for safe and effective pharmacotherapy for addressing unmet needs of these patients. Concomitant use of dexamethasone and tetracyclines, by virtue of their immunomodulatory and other relevant pharmacological properties, offers a potential strategy for synergy aimed at improving clinical outcomes.Areas covered: Here we review the potential benefits of combining dexamethasone and tetracyclines (minocycline or doxycycline) for the management of severe COVID-19 patients. We have critically examined the evidence obtained from in silico, experimental, and clinical research. We have also discussed the plausible mechanisms, advantages, and drawbacks of this proposed combination therapy for managing severe COVID-19.Expert opinion: The concomitant use of dexamethasone and one of the tetracyclines among severe COVID-19 patients offers several advantages in terms of additive immunomodulatory effects, cost-effectiveness, wide-availability, and well-known pharmacological properties including adverse-effect profile and contraindications. There is an urgent need to facilitate pilot studies followed by well-designed and adequately-powered multicentric clinical trials to generate conclusive evidence related to utility of this approach.

Gene Expression and Resistance to Glucocorticoid-Induced Apoptosis in Acute Lymphoblastic Leukemia: A Brief Review and Update

BACKGROUND

Resistance to glucocorticoid (GC)-induced apoptosis in Acute Lymphoblastic Leukemia (ALL), is considered one of the major prognostic factors for the disease. Prednisolone is a corticosteroid and one of the most important agents in the treatment of acute lymphoblastic leukemia. The mechanics of GC resistance are largely unknown and intense ongoing research focuses on this topic.

AIM

The aim of the present study is to review some aspects of GC resistance in ALL, and in particular of Prednisolone, with emphasis on previous and present knowledge on gene expression and signaling pathways playing a role in the phenomenon.

METHODS

An electronic literature search was conducted by the authors from 1994 to June 2019. Original articles and systematic reviews selected, and the titles and abstracts of papers screened to determine whether they met the eligibility criteria, and full texts of the selected articles were retrieved.

RESULTS

Identification of gene targets responsible for glucocorticoid resistance may allow discovery of drugs, which in combination with glucocorticoids may increase the effectiveness of anti-leukemia therapies. The inherent plasticity of clinically evolving cancer justifies approaches to characterize and prevent undesirable activation of early oncogenic pathways.

CONCLUSION

Study of the pattern of intracellular signal pathway activation by anticancer drugs can lead to development of efficient treatment strategies by reducing detrimental secondary effects.

Galangin Inhibits LPS-Induced MMP-9 Expression via Suppressing Protein Kinase-Dependent AP-1 and FoxO1 Activation in Rat Brain Astrocytes

Purpose

Neuroinflammation, characterized by the increased expression of inflammatory proteins such as matrix metalloproteinases (MMPs), plays a critical role in neurodegenerative disorders. Lipopolysaccharide (LPS) has been shown to upregulate MMP-9 expression through the activation of various transcription factors, including activator protein 1 (AP-1) and forkhead box protein O1 (FoxO1). The flavonoid 3,5,7-trihydroxy-2-phenyl-4H-1-benzopyran-4-one (galangin) has been demonstrated to possess antioxidant and anti-inflammatory properties in various types of cells. Here, we investigated the mechanisms underlying the inhibitory effect of galangin on LPS-induced MMP-9 expression in rat brain astrocytes (RBA-1 cells).

Methods

Pharmacological inhibitors and siRNAs were employed to explore the effects of galangin on LPS-challenged RBA-1 cells. Gelatin zymography, Western blotting, real-time PCR, and a luciferase reporter assay were used to detect MMP-9 activity, protein expression, mRNA levels, and promoter activity, respectively. The protein kinases involved in the LPS-induced MMP-9 expression were determined by Western blot. A chromatin immunoprecipitation (ChIP) assay was employed to evaluate the activity of c-Jun at the MMP-9 promoter.

Results

Galangin treatment attenuated the LPS-mediated induction of MMP-9 protein and mRNA expression, as well as the activity at the MMP-9 promoter. In addition, galangin exerted its inhibitory effects on MMP-9 expression through suppressing the LPS-stimulated activation of proline-rich tyrosine kinase (Pyk2), platelet-derived growth factor receptor beta (PDGFRβ), phosphoinositide 3-kinase (PI3K), protein kinase B (Akt), mammalian target of rapamycin (mTOR), and mitogen-activated protein kinases (MAPKs). Pretreatment with galangin attenuated the LPS-induced phosphorylation of c-Jun and FoxO1. LPS-induced cell migration was also suppressed by galangin pretreatment.

Conclusion

Galangin attenuates the LPS-induced inflammatory responses, including the induction of MMP-9 expression and cell migration, via inhibiting Pyk2/PDGFRβ/PI3K/Akt/mTOR/JNK1/JNK2 and p44/p42 MAPK cascade-dependent AP-1 and FoxO1 activities. These results provide new insights into the mechanisms through which galangin mitigates LPS-induced inflammatory responses, and suggest novel strategies for the management of LPS-related brain diseases.

Pristimerin Inhibits MMP-9 Expression and Cell Migration Through Attenuating NOX/ROS-Dependent NF-κB Activation in Rat Brain Astrocytes Challenged with LPS

Purpose

Neuroinflammation plays a crucial role in neurodegenerative diseases. Matrix metalloproteinases (MMPs) are a landmark of neuroinflammation. Lipopolysaccharide (LPS) has been demonstrated to induce MMP-9 expression. The mechanisms underlying LPS-induced MMP-9 expression have not been completely elucidated in astrocytes. Nuclear factor-kappaB (NF-κB) is well known as one of the crucial transcription factors in MMP-9 induction. Moreover, reactive oxygen species (ROS) could be an important mediator of neuroinflammation. Here, we differentiated whether ROS and NF-κB contributed to LPS-mediated MMP-9 expression in rat brain astrocytes (RBA-1). Besides, pristimerin has been revealed to possess antioxidant and anti-inflammatory effects. We also evaluated the effects of pristimerin on LPS-induced inflammatory responses.

Methods

RBA-1 cells were used for analyses. Pharmacological inhibitors and siRNAs were used to evaluate the signaling pathway. Western blotting and gelatin zymography were conducted to evaluate protein and MMP-9 expression, respectively. Real-time PCR was for mRNA expression. Wound healing assay was for cell migration. 2',7'-dichlorodihydrofluorescein diacetate (H₂DCF-DA) and dihydroethidium (DHE) staining were for ROS generation. Immunofluorescence staining was conducted to assess NF-κB p65. Promoter-reporter gene assay and chromatin immunoprecipitation (ChIP) assay were used to detect promoter activity and the association of nuclear proteins with the promoter.

Results

Our results showed that the increased level of ROS generation was attenuated by edaravone (a ROS scavenger), apocynin (APO; an inhibitor of p47^Phox), diphenyleneiodonium (DPI; an inhibitor of NOX), and pristimerin in RBA-1 cells exposed to LPS. Besides, pretreatment with APO, DPI, edaravone, Bay11-7082, and pristimerin also inhibited the phosphorylation, nuclear translocation, promoter binding activity of NF-κB p65 as well as upregulation of MMP-9 expression-mediated cell migration in RBA-1 cells challenged with LPS.

Conclusion

These results suggested that LPS enhances the upregulation of MMP-9 through nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX)/ROS-dependent NF-κB activity. These results also provide new insights into the mechanisms by which pristimerin attenuates LPS-mediated MMP-9 expression and neuroinflammatory responses.

Medroxyprogesterone Acetate Impairs Amyloid Beta Degradation in a Matrix Metalloproteinase-9 Dependent Manner

Despite the extensive use of hormonal methods as either contraception or menopausal hormone therapy (HT), there is very little known about the potential effects of these compounds on the cellular processes of the brain. Medroxyprogesterone Acetate (MPA) is a progestogen used globally in the hormonal contraceptive, Depo Provera, by women in their reproductive prime and is a major compound found in HT formulations used by menopausal women. MPA promotes changes in the circulating levels of matrix metalloproteinases (MMPs), such as MMP-9, in the endometrium, yet limited literature studying the effects of MPA on neurons and astroglia cells has been conducted. Additionally, the dysregulation of MMPs has been implicated in the pathology of Alzheimer's disease (AD), where inhibiting the secretion of MMP-9 from astroglia reduces the proteolytic degradation of amyloid-beta. Thus, we hypothesize that exposure to MPA disrupts proteolytic degradation of amyloid-beta through the downregulation of MMP-9 expression and subsequent secretion. To assess the effect of progestins on MMP-9 and amyloid-beta, in vitro, C6 rat glial cells were exposed to MPA for 48 h and then the enzymatic, secretory, and amyloid-beta degrading capacity of MMP-9 was assessed from the conditioned culture medium. We found that MPA treatment inhibited transcription of MMP-9, which resulted in a subsequent decrease in the production and secretion of MMP-9 protein, in part through the glucocorticoid receptor. Additionally, we investigated the consequences of amyloid beta-degrading activity and found that MPA treatment decreased proteolytic degradation of amyloid-beta. Our results suggest MPA suppresses amyloid-beta degradation in an MMP-9-dependent manner, in vitro, and potentially compromises the clearance of amyloid-beta in vivo.

Lipopolysaccharide-Induced Matrix Metalloproteinase-9 Expression Associated with Cell Migration in Rat Brain Astrocytes

Neuroinflammation is a landmark of neuroinflammatory and neurodegenerative diseases. Matrix metalloproteinase (MMP)-9, one member of MMPs, has been shown to contribute to the pathology of these brain diseases. Several experimental models have demonstrated that lipopolysaccharide (LPS) exerts a pathological role through Toll-like receptors (TLRs) in neuroinflammation and neurodegeneration. However, the mechanisms underlying LPS-induced MMP-9 expression in rat brain astrocytes (RBA-1) are not completely understood. Here, we applied pharmacological inhibitors and siRNA transfection to assess the levels of MMP-9 protein, mRNA, and promoter activity, as well as protein kinase phosphorylation in RBA-1 cells triggered by LPS. We found that LPS-induced expression of pro-form MMP-9 and cell migration were mediated through TLR4, proto-oncogene tyrosine-protein kinase (c-Src), proline-rich tyrosine kinase 2 (Pyk2), platelet-derived growth factor receptor (PDGFR), phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt), p38 mitogen-activated protein kinase (MAPK), and Jun amino-terminal kinase (JNK)1/2 signaling molecules in RBA-1 cells. In addition, LPS-stimulated binding of c-Jun to the MMP-9 promoter was confirmed by chromatin immunoprecipitation (ChIP) assay, which was blocked by pretreatment with c-Src inhibitor II, PF431396, AG1296, LY294002, Akt inhibitor VIII, p38 MAP kinase inhibitor VIII, SP600125, and tanshinone IIA. These results suggest that in RBA-1 cells, LPS activates a TLR4/c-Src/Pyk2/PDGFR/PI3K/Akt/p38 MAPK and JNK1/2 pathway, which in turn triggers activator protein 1 (AP-1) activation and ultimately induces MMP-9 expression and cell migration.

GATA6 Regulates Aortic Valve Remodeling, and Its Haploinsufficiency Leads to Right-Left Type Bicuspid Aortic Valve

BACKGROUND

Bicuspid aortic valve (BAV), the most common congenital heart defect affecting 1% to 2% of the population, is a major risk factor for premature aortic valve disease and accounts for the majority of valve replacement. The genetic basis and mechanisms of BAV etiology and pathogenesis remain largely undefined.

METHODS

Cardiac structure and function was assessed in mice lacking a Gata6 allele. Human GATA6 gene variants were analyzed in 452 BAV cases from the BAV consortium and 1849 controls from the Framingham GWAS (Genome Wide Association Study). GATA6 expression was determined in mice and human tissues using quantitative real-time polymerase chain reaction and immunohistochemistry. Mechanistic studies were carried out in cultured cells.

RESULTS

Gata6 heterozygous mice have highly penetrant right-left (RL)-type BAV, the most frequent type in humans. GATA6 transcript levels are lower in human BAV compared with normal tricuspid valves. Mechanistically, Gata6 haploinsufficiency disrupts valve remodeling and extracellular matrix composition through dysregulation of important signaling molecules, including matrix metalloproteinase 9. Cell-specific inactivation of Gata6 reveals an essential role for GATA6 in secondary heart field myocytes because loss of 1 Gata6 allele from Isl- 1-positive cells-but not from endothelial or neural crest cells-recapitulates the phenotype of Gata6 heterozygous mice.

CONCLUSIONS

The data identify a new cellular and molecular mechanism underlying BAV. The availability of an animal model for the most frequent human BAV opens the way for the elucidation of BAV pathogenesis and the development of much needed therapies.

The role of microRNAs in the involvement of vascular smooth muscle cells in the development of atherosclerosis

MicroRNAs (miRNAs) are a class of nonprotein-encoding RNAs of ~22 nucleotides in length that bind to or complement each other with a target gene messenger RNA (mRNA) to promote mRNA degradation or inhibit translation of the target mRNA. The protein required [such as Toll-like receptor (TLR) proteins] is controlled at an optimal level. By affecting protein translation, miRNAs have become powerful regulators of biological processes, including development, differentiation, cell proliferation, and apoptosis. MiRNAs are involved in the regulation of proliferation, migration, and apoptosis of vascular smooth muscle cells (VSMCs), thereby affecting the formation of atherosclerosis (AS). In recent years, the role and mechanism of miRNAs involved in AS development in VSMCs have been studied extensively. In the current study, the results and progress in miRNA research are reviewed.

Matrix Metalloproteinases in Renal Diseases: A Critical Appraisal

Matrix metalloproteinases (MMPs) are endopeptidases within the metzincin protein family that not only cleave extracellular matrix (ECM) components, but also process the non-ECM molecules, including various growth factors and their binding proteins. MMPs participate in cell to ECM interactions, and MMPs are known to be involved in cell proliferation mechanisms and most probably apoptosis. These proteinases are grouped into six classes: collagenases, gelatinases, stromelysins, matrilysins, membrane type MMPs, and other MMPs. Various mechanisms regulate the activity of MMPs, inhibition by tissue inhibitors of metalloproteinases being the most important. In the kidney, intrinsic glomerular cells and tubular epithelial cells synthesize several MMPs. The measurement of circulating MMPs can provide valuable information in patients with kidney diseases. They play an important role in many renal diseases, both acute and chronic. This review attempts to summarize the current knowledge of MMPs in the kidney and discusses recent data from patient and animal studies with reference to specific diseases. A better understanding of the MMPs' role in renal remodeling may open the way to new interventions favoring deleterious renal changes in a number of kidney diseases.

RTA 408 Inhibits Interleukin-1β-Induced MMP-9 Expression via Suppressing Protein Kinase-Dependent NF-κB and AP-1 Activation in Rat Brain Astrocytes

Neuroinflammation is characterized by the elevated expression of various inflammatory proteins, including matrix metalloproteinases (MMPs), induced by various pro-inflammatory mediators, which play a critical role in neurodegenerative disorders. Interleukin-1β (IL-1β) has been shown to induce the upregulation of MMP-9 through nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX)-reactive oxygen species (ROS)-dependent signaling pathways. N-(2-cyano-3,12-dioxo-28-noroleana-1,9(11)-dien-17-yl)-2-2-difluoropropanamide (RTA 408), a novel synthetic triterpenoid, has been shown to possess anti-oxidant and anti-inflammatory properties in various types of cells. Here, we evaluated the effects of RTA 408 on IL-1β-induced inflammatory responses by suppressing MMP-9 expression in a rat brain astrocyte (RBA-1) line. IL-1β-induced MMP-9 protein and mRNA expression, and promoter activity were attenuated by RTA 408. The increased level of ROS generation in RBA-1 cells exposed to IL-1β was attenuated by RTA 408, as determined by using 2′,7′-dichlorodihydrofluorescein diacetate (DCFH-DA) and CellROX. In addition, the inhibitory effects of RTA 408 on MMP-9 expression resulted from the suppression of the IL-1β-stimulated activation of Pyk2 (proline-rich tyrosine kinase), platelet-derived growth factor receptor β (PDGFRβ), Akt, ROS, and mitogen-activated protein kinases (MAPKs). Pretreatment with RTA 408 attenuated the IL-1β-induced c-Jun phosphorylation, mRNA expression, and promoter activity. IL-1β-stimulated nuclear factor-κB (NF-κB) p65 phosphorylation, translocation, and promoter activity were also attenuated by RTA 408. Furthermore, IL-1β-induced glial fibrillary acidic protein (GFAP) protein and mRNA expression, and cell migration were attenuated by pretreatment with RTA 408. These results provide new insights into the mechanisms by which RTA 408 attenuates IL-1β-mediated inflammatory responses and exerts beneficial effects for the management of brain diseases.

ANP32E, a Protein Involved in Steroid-Refractoriness in Ulcerative Colitis, Identified by a Systems Biology Approach

BACKGROUND AND AIMS

Steroid-refractoriness is a common and unpredictable phenomenon in ulcerative colitis [UC], but there are no conclusive studies on the molecular functions involved. We aimed to assess the mechanism of action related to steroid failure by integrating transcriptomic data from UC patients, and updated molecular data on UC and glucocorticoids.

METHODS

MicroRNA [miRNA] and mRNA expression were evaluated by sequencing and microarrays, respectively, from rectal biopsies of patients with moderately-to-severe active UC, obtained before and on the third day of steroid treatment. The differential results were integrated into the mathematical models generated by a systems biology approach.

RESULTS

This computational approach identified 18 proteins that stand out either by being associated with the mechanism of action or by providing a means to classify the patients according to steroid response. Their biological functions have been linked to inflammation, glucocorticoid-induced transcription and angiogenesis. All the selected proteins except ANP32E [a chaperone which has been linked to the exchange of H2A.z histone and promotes glucocorticoid receptor-induced transcription] had previously been related to UC and/or glucocorticoid-induced biological actions. Western blot and immunofluorescence assays confirmed the implication of this chaperone in steroid failure in patients with active UC.

CONCLUSIONS

A systems biology approach allowed us to identify a comprehensive mechanism of action of steroid-refractoriness, highlighting the key role of steroid-induced transcription and the potential implication of ANP32E in this phenomenon.

Renal Damaging Effect Elicited by Bicalutamide Therapy Uncovered Multiple Action Mechanisms As Evidenced by the Cell Model

Bicalutamide (Bic) is frequently used in androgen deprivation therapy (ADT) for treating prostate cancer. ADT-induced hypogonadism was reported to have the potential to lead to acute kidney injury (AKI). ADT was also shown to induce bladder fibrosis via induction of the transforming growth factor (TGF)-β level. We hypothesized that Bic can likely induce renal fibrosis. To understand this, a cell model was used to explore expressions of relevant profibrotic proteins. Results indicated that Bic initiated multiple apoptotic and fibrotic pathways, including androgen deprivation, downregulation of the androgen receptor → phosphatidylinositol-3-kinase → Akt pathway, upregulation of the extrinsic apoptotic pathway- tumor necrosis factor α →  nuclear factor κB → caspase-3, increased expressions of fibrosis-related proteins including platelet-derived growth factor β, fibronectin and collagen IV, and enhanced cell migration. The endoplasmic reticular stress pathway and smooth muscle actin were unaffected by Bic. Co-treatment with testosterone was shown to have an anti-apoptotic effect against Bic, suggesting a better outcome of Bic therapy if administered with an appropriate testosterone intervention. However, since Bic was found to inhibit the membrane transport and consumption rates of testosterone, a slightly larger dose of testosterone is recommended. In conclusion, these pathways can be considered to be pharmaceutically relevant targets for drug development in treating the adverse effects of Bic.

Suppression of PMA-induced human fibrosarcoma HT-1080 invasion and metastasis by kahweol via inhibiting Akt/JNK1/2/p38 MAPK signal pathway and NF-κB dependent transcriptional activities

Coffee is one of the widely sales beverage worldwide and contains numerous phytochemicals that are beneficial to health. Kahweol acetate (KA), a coffee-specific diterpene, exhibits anti-tumoric properties in human tumoric cells. However, the effect of KA on the metastasis and invasion of cancer cells and the underlying mechanisms remain unclear. The objectives of this study were to estimate the anti-tumor activity of KA and reveal the possible molecular mechanisms. KA markedly inhibited the cell proliferation enhanced by phorbol 12-myristate 13-acetate (PMA) in human fibrosarcoma cells. As well as, KA attenuated PMA-induced cell migration and invasion in a concentration-dependent manner. KA suppressed PMA-enhanced activation of matrix metalloproteinase-9 (MMP-9) through suppression of nuclear factor kappa B (NF-κB) activation. KA repressed the PMA-induced phosphorylation of Akt, c-Jun N-terminal kinase (JNK) 1/2, and p38 MAPK, which are signaling molecules upstream of MMP-9 expression. In summary, we demonstrated that the anti-tumor effects of KA might occur through the inhibition of Akt/JNK1/2/p38 MAPK phosphorylation and downregulation of NF-κB activation, leading to a decrease in MMP-9 expression. Thus, KA is a useful chemotherapeutic agent that may contribute to prevent to the metastatic tumor.

11β-HSD1 in Human Fetal Membranes as a Potential Therapeutic Target for Preterm Birth

Human parturition is a complex process involving interactions between the myometrium and signals derived from the placenta, fetal membranes, and fetus. Signals originating from fetal membranes are crucial components that trigger parturition, which is clearly illustrated by the labor-initiating consequence of membrane rupture. It has been recognized for a long time that among fetal tissues in late gestation the fetal membranes possess the highest capacity for cortisol regeneration by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). However, the exact role of this unique feature remains a mystery. Accumulating evidence indicates that this extra-adrenal source of cortisol may serve as an upstream signal for critical events in human parturition, including enhanced prostaglandin and estrogen synthesis as well as extracellular matrix remodeling. This may explain why such high capacity for cortisol regeneration develops in human fetal membranes at late gestation. Therefore, inhibition of 11β-HSD1 may provide a potential therapeutic target for prevention of preterm birth. This review summarizes the current understanding of the functional role of cortisol regeneration by 11β-HSD1 in human fetal membranes.

nr3c1 null mutant zebrafish are viable and reveal DNA-binding-independent activities of the glucocorticoid receptor

Glucocorticoids (GCs) play important roles in developmental and physiological processes through the transcriptional activity of their cognate receptor (Gr). Using CRISPR/Cas9 technology, we established a zebrafish null Gr mutant line and compared its phenotypes with wild type and a zebrafish line with partially silenced gr (gr^s357/s357). Homozygous gr^−/− larvae are morphologically inconspicuous and, in contrast to GR^−/− knockout mice, viable through adulthood, although with reduced fitness and early life survival. Mutants gr^−/− are fertile, but their reproductive capabilities fall at around 10 months of age, when, together with cardiac and intestinal abnormalities already visible at earlier stages, increased fat deposits are also observed. Mutants show higher levels of whole-body cortisol associated with overstimulated basal levels of crh and pomca transcripts along the HPI axis, which is unresponsive to a mechanical stressor. Transcriptional activity linked to immune response is also hampered in the gr^−/− line: after intestinal damage by dextran sodium sulphate exposure, there are neither inflammatory nor anti-inflammatory cytokine gene responses, substantiating the hypothesis of a dual-action of the GC-GR complex on the immune system. Hence, the zebrafish gr mutant line appears as a useful tool to investigate Gr functions in an integrated in vivo model.

Redox signaling in the gastrointestinal tract

Redox signaling regulates physiological self-renewal, proliferation, migration and differentiation in gastrointestinal epithelium by modulating Wnt/β-catenin and Notch signaling pathways mainly through NADPH oxidases (NOXs). In the intestine, intracellular and extracellular thiol redox status modulates the proliferative potential of epithelial cells. Furthermore, commensal bacteria contribute to intestine epithelial homeostasis through NOX1- and dual oxidase 2-derived reactive oxygen species (ROS). The loss of redox homeostasis is involved in the pathogenesis and development of a wide diversity of gastrointestinal disorders, such as Barrett's esophagus, esophageal adenocarcinoma, peptic ulcer, gastric cancer, ischemic intestinal injury, celiac disease, inflammatory bowel disease and colorectal cancer. The overproduction of superoxide anion together with inactivation of superoxide dismutase are involved in the pathogenesis of Barrett's esophagus and its transformation to adenocarcinoma. In Helicobacter pylori-induced peptic ulcer, oxidative stress derived from the leukocyte infiltrate and NOX1 aggravates mucosal damage, especially in HspB+ strains that downregulate Nrf2. In celiac disease, oxidative stress mediates most of the cytotoxic effects induced by gluten peptides and increases transglutaminase levels, whereas nitrosative stress contributes to the impairment of tight junctions. Progression of inflammatory bowel disease relies on the balance between pro-inflammatory redox-sensitive pathways, such as NLRP3 inflammasome and NF-κB, and the adaptive up-regulation of Mn superoxide dismutase and glutathione peroxidase 2. In colorectal cancer, redox signaling exhibits two Janus faces: On the one hand, NOX1 up-regulation and derived hydrogen peroxide enhance Wnt/β-catenin and Notch proliferating pathways; on the other hand, ROS may disrupt tumor progression through different pro-apoptotic mechanisms. In conclusion, redox signaling plays a critical role in the physiology and pathophysiology of gastrointestinal tract.

Pseudomonas aeruginosa quorum-sensing signaling molecule N-3-oxododecanoyl homoserine lactone induces matrix metalloproteinase 9 expression via the AP1 pathway in rat fibroblasts

Quorum sensing is a cell-to-cell communication mechanism, which is responsible for regulating a number of bacterial virulence factors and biofilm maturation and therefore plays an important role for establishing wound infection. Quorum-sensing signals may induce inflammation and predispose wounds to infection by Pseudomonas aeruginosa; however, the interaction has not been well investigated. We examined the effects of the P. aeruginosa las quorum-sensing signal, N-3-oxo-dodecanoyl homoserine lactone (3OC12-HSL), on matrix metalloproteinase (MMP) 9 expression in Rat-1 fibroblasts. 3OC12-HSL upregulated the expression of the MMP9 gene bearing an activator protein-1 (AP-1) binding site in the promoter region. We further investigated the mechanism underlying this effect. c-Fos gene expression increased rapidly after exposure to 3OC12-HSL, and nuclear translocation of c-Fos protein was observed; both effects were reduced by pretreatment with an AP-1 inhibitor. These results suggest that 3OC12-HSL can alter MMP9 gene expression in fibroblasts via the AP-1 signaling pathway.

miR-29c induction contributes to downregulation of vascular extracellular matrix proteins by glucocorticoids

Maternal undernutrition increases maternal glucocorticoids (GCs) and alters microRNA expression in offspring. Given that the mechanisms of GC action on vascular development are not clear, this study examined the influence of GCs on microRNA 29c (miR-29c) and its predicted targets in primary rat aorta smooth muscle cells (RAOSMCs). Dexamethasone (Dex) and corticosterone (Cor) time-dependently increased miR-29c expression and reduced collagen type III (Col3A1), collagen type IV (Col4A5), elastin (ELN), and matrix metalloproteinase-2 (MMP2) protein in RAOSMCs. These effects were blocked by mifepristone. These genes were also targeted by miR-29c, as confirmed by a significant decrease in luciferase reporter activity of Col3A1 (34%), Col4A5 (45%), ELN (17%), and MMP2 (28%). In cells transfected with reporter plasmids, including the 3'-untranslated region of genes targeted by miR-29c, treatment with Dex or Cor also resulted in decreases in luciferase activity. Gain or loss of function of miR-29c significantly altered mRNA expression of Col3A1 (26% and 26%, respectively), Col4A5 (28% and 32%, respectively), and MMP2 (24% and 14%, respectively) but did not affect ELN. Gain or loss of function of miR-29c also significantly altered protein levels of Col3A1 (51% and 16%, respectively), Col4A5 (56% and 22%, respectively), ELN (53% and 71%, respectively), and MMP2 (28% and 53%, respectively). Coincubation of anti-miR-29c with Dex or Cor partially attenuated the effects of these steroids on protein expression of Col3A1 (25% and 24%, respectively), Col4A5 (26% and 44%, respectively), ELN (31% and 55%, respectively), and MMP2 (46% and 26%, respectively) in RAOSMCs compared with anti-miR negative controls. Our results demonstrate that GCs regulate the expression of Col3A1, Col4A5, ELN, and MMP2, at least in part, through induction of miR-29c.

Matrix metalloproteinase 9 modulates collagen matrices and wound repair

Acute and chronic injuries are characterized by leukocyte infiltration into tissues. Although matrix metalloproteinase 9 (Mmp9) has been implicated in both conditions, its role in wound repair remains unclear. We previously reported a zebrafish chronic inflammation mutant caused by an insertion in the hepatocyte growth factor activator inhibitor gene 1 (hai1; also known as spint1) that is characterized by epithelial extrusions and neutrophil infiltration into the fin. Here, we performed a microarray analysis and found increased inflammatory gene expression in the mutant larvae, including a marked increase in mmp9 expression. Depletion of mmp9 partially rescued the chronic inflammation and epithelial phenotypes, in addition to restoring collagen fiber organization, as detected by second-harmonic generation imaging. Additionally, we found that acute wounding induces epithelial cell mmp9 expression and is associated with a thickening of collagen fibers. Interestingly, depletion of mmp9 impaired this collagen fiber reorganization. Moreover, mmp9 depletion impaired tissue regeneration after tail transection, implicating Mmp9 in acute wound repair. Thus, Mmp9 regulates both acute and chronic tissue damage and plays an essential role in collagen reorganization during wound repair.

Integrin α3β1 signaling through MEK/ERK determines alternative polyadenylation of the MMP-9 mRNA transcript in immortalized mouse keratinocytes

Integrin α3β1 is highly expressed in both normal and tumorigenic epidermal keratinocytes where it regulates genes that control cellular function and extracellular matrix remodeling during normal and pathological tissue remodeling processes, including wound healing and development of squamous cell carcinoma (SCC). Previous studies identified a role for α3β1 in immortalized and transformed keratinocytes in the regulation of genes that promote tumorigenesis, invasion, and pro-angiogenic crosstalk to endothelial cells. One such gene, matrix metalloproteinase-9 (MMP-9), is induced by α3β1 through a post-transcriptional mechanism of enhanced mRNA stability. In the current study, we sought to investigate the mechanism through which α3β1 controls MMP-9 mRNA stability. First, we utilized a luciferase reporter assay to show that AU-rich elements (AREs) residing within the 3’-untranslated region (3’-UTR) of the MMP-9 mRNA renders the transcript unstable in a manner that is independent of α3β1. Next, we cloned a truncated variant of the MMP-9 mRNA which is generated through usage of an alternative, upstream polyadenylation signal and lacks the 3’-UTR region containing the destabilizing AREs. Using an RNase protection assay to distinguish “long” (full-length 3’-UTR) and “short” (truncated 3’-UTR) MMP-9 mRNA variants, we demonstrated that the shorter, more stable mRNA that lacks 3’-UTR AREs was preferentially generated in α3β1-expressing keratinocytes compared with α3β1-deficient (i.e., α3-null) keratinocytes. Moreover, we determined that α3β1-dependent alternative polyadenylation was acquired by immortalized keratinocytes, as primary neonatal keratinocytes did not display α3β1-dependent differences in the long and short transcripts. Finally, pharmacological inhibition of the extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) pathway in α3β1-expressing keratinocytes caused a shift towards long variant expression, while Raf-1-mediated activation of ERK in α3-null keratinocytes dramatically enhanced short variant expression, indicating a role for ERK/MAPK signaling in α3β1-mediated selection of the proximal polyadenylation site. These findings identify a novel mode of integrin α3β1-mediated gene regulation through alternative polyadenylation.

Tumor necrosis factor-α regulates matrix metalloproteinase-2 expression and cell migration via ERK pathway in rat glomerular mesangial cells

Mesangial cells (MCs), vascular smooth muscle-derived cells, contribute to glomerular injury by generating a number of cytokines such as tumor necrosis factor-α (TNF-α). Matrix metalloproteinases (MMPs), regulated by various stimuli, are important in remodeling of glomerular ECM, which leads to a number of renal diseases. We investigated whether TNF-α participated in the regulation of MMPs and explored signal pathways involved in TNF-α-induced MMPs expression in rat glomerular MCs. Western blot and RT-qPCR results showed that treatment with TNF-α significantly increased the expression of MMP-2, but not MMP-9 at both protein and mRNA levels in rat glomerular MCs. The extracellular signal-regulated kinase (ERK) and nuclear factor-kappaB (NF-κB) signal pathways were activated by TNF-α. Moreover, the activation of NF-κB pathway in rat MCs was effectively inhibited by PD98059, specific inhibitor of ERK, suggesting a role for ERK in regulating NF-κB function. PD98059 or NF-κB signal pathway selective inhibitor Bay 11-7082 effectively blocked TNF-α-induced expression of MMP-2 in rat MCs, as determined by gene and protein expression. C-jun N-terminal kinase (JNK) signal pathway had no effect on TNF-α-induced expression of MMP-2, even though it was also activated by TNF-α in rat MCs. Furthermore, TNF-α could induce the cell migration of rat MCs, whereas ERK signal pathway specific inhibitor PD98059 compromised the cell migration triggered by TNF-α. Thus, TNF-α upregulates the expression of MMP-2 via activation of ERK-dependent NF-κB pathway in rat MCs, which may contribute to the cell migration of rat MCs.

Roles of pro-angiogenic and anti-angiogenic factors as well as matrix metalloproteinases in healing of NSAID-induced small intestinal ulcers in rats

AIMS

We examined changes in the expression of a pro-angiogenic factor, vascular endothelial growth factor (VEGF), and an anti-angiogenic factor, endostatin, as well as matrix metalloproteinase (MMP)-2 and MMP-9 in the rat small intestine after administration of indomethacin and investigated the roles of these factors in the healing of indomethacin-induced small intestinal ulcers.

MAIN METHODS

Male SD rats were given indomethacin (10mg/kg) p.o. and euthanized at various time points (3-24h and 2-7days) after the administration. To impair the healing of these lesions, low-dose of indomethacin (2mg/kg) was given p.o. once daily for 6days starting 1day after ulceration. Levels of VEGF, endostatin, MMP-2 and MMP-9 were determined by Western blotting.

KEY FINDINGS

The expression of both VEGF and endostatin was upregulated after the ulceration. Repeated administration of low-dose indomethacin impaired the ulcer healing with a decrease of VEGF expression and a further increase of endostatin expression, resulting in a marked decrease in the ratio of VEGF/endostatin expression. The levels of MMP-2 and MMP-9 were both significantly increased after the ulceration, but these responses were suppressed by the repeated indomethacin treatment. The healing of these ulcers was significantly delayed by the repeated administration of MMP inhibitors such as ARP-101 and SB-3CT.

SIGNIFICANCE

The results confirm the importance of the balance between pro-angiogenic and anti-angiogenic activities in the healing of indomethacin-induced small intestinal damage and further suggest that the increased expression of MMP-2 and MMP-9 is another important factor for ulcer healing in the small intestine.

Matrix metalloproteinase (MMP) 9 transcription in mouse brain induced by fear learning

Memory formation requires learning-based molecular and structural changes in neurons, whereas matrix metalloproteinase (MMP) 9 is involved in the synaptic plasticity by cleaving extracellular matrix proteins and, thus, is associated with learning processes in the mammalian brain. Because the mechanisms of MMP-9 transcription in the brain are poorly understood, this study aimed to elucidate regulation of MMP-9 gene expression in the mouse brain after fear learning. We show here that contextual fear conditioning markedly increases MMP-9 transcription, followed by enhanced enzymatic levels in the three major brain structures implicated in fear learning, i.e. the amygdala, hippocampus, and prefrontal cortex. To reveal the role of AP-1 transcription factor in MMP-9 gene expression, we have used reporter gene constructs with specifically mutated AP-1 gene promoter sites. The constructs were introduced into the medial prefrontal cortex of neonatal mouse pups by electroporation, and the regulation of MMP-9 transcription was studied after contextual fear conditioning in the adult animals. Specifically, -42/-50- and -478/-486-bp AP-1 binding motifs of the mouse MMP-9 promoter sequence have been found to play a major role in MMP-9 gene activation. Furthermore, increases in MMP-9 gene promoter binding by the AP-1 transcription factor proteins c-Fos and c-Jun have been demonstrated in all three brain structures under investigation. Hence, our results suggest that AP-1 acts as a positive regulator of MMP-9 transcription in the brain following fear learning.

Molecular mechanisms of PDGF-AA expression induced by the dsRNA-mimetic poly (I:C) and IL-18

Several animal studies suggest a role of platelet-derived growth factors (PDGFs) particularly A and B in atherosclerosis. Previously, it has been shown that viral infections have the ability to initiate and accelerate atherosclerosis in animal models. Recently, it has been reported that IL-18 has a pro-atherogenic character. Moreover, viral infections have been shown to be associated with induction of IL-18 bioactivity. By using human predendritic KG1 cells, we sought to assess PDGF-AA production under the influence of IL-18 and the byproduct of viral replication, dsRNA-mimetic poly (I:C). Here we demonstrate that poly (I:C) and IL-18 have the ability to induce PDGF-AA expression. In addition, costimulation of KG-1 cells with both IL-18 plus poly (I:C) shows an additive effect on PDGF-AA production. Furthermore, we demonstrate that neither p38 nor SAPK/JNK is required for PDGF-AA production by both PIC and IL-18. However, the expression of PDGF-AA has been found to be associated with increased activation of NF-κB and enhancement of DNA-binding capacity of NF-κB as shown by electrophoretic mobility shift assay (EMSA) and supershift analysis. Collectively, this study demonstrates that the byproduct of viral replication, dsRNA [poly (I:C)], and IL-18 have the ability to induce PDGF-AA in NF-κB-dependent manner. Furthermore, dsRNA act in an additive way with IL-18 to induce PDGF-AA which plays a major role in atherosclerosis. These data might help to understand the pro-atherogenic character of IL-18 and molecular mechanisms of viral infection-induced atherosclerosis.

Brain-derived neurotrophic factor induces matrix metalloproteinase 9 expression in neurons via the serum response factor/c-Fos pathway

Brain-derived neurotrophic factor (BDNF) plays a pivotal role in the regulation of the transcription of genes that encode proplasticity proteins. In the present study, we provide evidence that stimulation of rat primary cortical neurons with BDNF upregulates matrix metalloproteinase 9 (MMP-9) mRNA and protein levels and increases enzymatic activity. The BDNF-induced MMP-9 transcription was dependent on extracellular signal-regulated kinase 1/2 (ERK1/2) pathway and c-Fos expression. Overexpression of AP-1 dimers in neurons led to MMP-9 promoter activation, with the most potent being those that contained c-Fos, whereas knockdown of endogenous c-Fos by small hairpin RNA (shRNA) reduced BDNF-mediated MMP-9 transcription. Additionally, mutation of the proximal AP-1 binding site in the MMP-9 promoter inhibited the activation of MMP-9 transcription. BDNF stimulation of neurons induced binding of endogenous c-Fos to the proximal MMP-9 promoter region. Furthermore, as the c-Fos gene is a known target of serum response factor (SRF), we investigated whether SRF contributes to MMP-9 transcription. Inhibition of SRF and its cofactors by either overexpression of dominant negative mutants or shRNA decreased MMP-9 promoter activation. In contrast, MMP-9 transcription was not dependent on CREB activity. Finally, we showed that neuronal activity stimulates MMP-9 transcription in a tyrosine kinase receptor B (TrkB)-dependent manner.

The involvement of oxidants and NF-κB in cytokine-induced MMP-9 synthesis by bone marrow-derived osteoprogenitor cells

OBJECTIVE AND DESIGN

The activity of immune cells affects the balance between bone mineralization and resorption carried out by the opposing actions of osteoblasts and osteoclasts, respectively. This study was aimed at determining the possible interaction between inflammatory conditions and collagen type I degrading MMP (mainly MMP-2 and MMP-9) synthesis and secretion in rat osteoprogenitors.

MATERIALS AND METHODS

The study was performed using primary rat bone marrow-derived osteoprogenitors during their advanced osteogenesis. Biochemical, immunohistochemical, and molecular biology techniques were used to investigate the influence of pro-inflammatory cytokines on MMP-2 and MMP-9 synthesis and secretion in osteoprogenitors.

RESULTS

Results indicated that both synthesis and secretion of MMPs (MMP-1, -2, -8, -9, and -13) were significantly induced after pro-inflammatory cytokine treatments, except MMP-2, whose levels remained unchanged. NF-κB (nuclear factor kappa-light chain enhancer of activated B cells) inhibition assays showed that induced MMP-9 secretion by inflammatory cytokines was mediated by activation of NF-κB via the classical pathway and that oxidants play a significant role in this signal transduction pathway. In contrast, no such effect was observed for synthesis of MMP-2.

CONCLUSIONS

These results indicate the possibility that inflammatory processes may trigger osteoblasts to absorb bone by secreting elevated levels of MMPs capable of degrading collagen type I, especially MMP-9 which is upregulated due to increased NF-κB transcription activity.

ETS1 promotes chemoresistance and invasion of paclitaxel-resistant, hormone-refractory PC3 prostate cancer cells by up-regulating MDR1 and MMP9 expression

ETS1, which belongs to the ETS transcription factor family, plays important roles in diverse aspects of cancer such as drug resistance and metastasis. In the present study, we examined the functional roles of ETS1 in paclitaxel resistance and invasion using human prostate cancer PC3 cells and paclitaxel-resistant PC3PR cells established from PC3 cells. Our results showed that ETS1mRNA and protein expression was markedly up-regulated in paclitaxel-resistant PC3PR cells compared with paclitaxel-sensitive PC3 cells. The mRNA levels of MDR1 as well as MMP1, MMP3, MMP9 and uPA were positively correlated with that of ETS1. In PC3PR cells, silencing of ETS1 expression by siRNAs inhibited the activity of the MDR1 promoter containing ETS binding sites, reduced the mRNA and protein levels of MDR1 and suppressed paclitaxel resistance. Furthermore, ETS1 knockdown decreased secretion of MMP9 as well as its intracellular mRNA level, and dramatically inhibited invasion of PC3PR cells. Our results suggest that ETS1 promotes paclitaxel resistance and invasion in part by up-regulating MDR1 and MMP9 expression. Taken together, a novel therapeutic strategy targeting the ETS1 gene could be designed to overcome chemoresistance and metastasis of taxane-resistant, hormone-refractory prostate cancer.

Saponins from the roots of Platycodon grandiflorum suppress ultraviolet A-induced matrix metalloproteinase-1 expression via MAPKs and NF-κB/AP-1-dependent signaling in HaCaT cells

Saponins from the roots of Platycodon grandiflorum (CKS) have been shown to exhibit many pharmacological activities, including anti-cancer and anti-inflammatory activities and antioxidant effects. However, anti-skin photoaging effects of CKS have not yet been reported. In this study, we investigated the protective effects of CKS against UVA damage on immortalized human keratinocytes (HaCaT). We then explored the inhibitory effects of CKS on UVA-induced MMP-1 and investigated the molecular mechanism underlying those effects. CKS increased the cell viability and inhibited reactive oxygen species (ROS) production in HaCaT cells exposed to UVA irradiation. Pre-treatment of HaCaT cells with CKS inhibited UVA-induced production of MMP-1 and MMP-9. In addition, CKS decreased UVA-induced expression of the inflammatory cytokines IL-1β and IL-6. Western blot analysis further revealed that CKS markedly suppressed the enhancement of collagen degradation in UVA-exposed HaCaT cells. CKS also suppressed UVA-induced activation of NF-κB or c-Jun and c-Fos, and the phosphorylation of MAPKs, which are upstream modulators of NF-κB and AP-1.

Nimbolide retards tumor cell migration, invasion, and angiogenesis by downregulating MMP-2/9 expression via inhibiting ERK1/2 and reducing DNA-binding activity of NF-κB in colon cancer cells

Nimbolide, a plant-derived limonoid has been shown to exert its antiproliferative effects in various cell lines. We demonstrate that nimbolide effectively inhibited proliferation of WiDr colon cancer cells through inhibition of cyclin A leading to S phase arrest. It also caused activation of caspase-mediated apoptosis through the inhibition of ERK1/2 and activation of p38 and JNK1/2. Further nimbolide effectively retarded tumor cell migration and invasion through inhibition of metalloproteinase-2/9 (MMP-2/9) expression, both at the mRNA and protein level. It was also a strong inhibitor of VEGF expression, promoter activity, and in vitro angiogenesis. Finally, nimbolide suppressed the nuclear translocation of p65/p50 and DNA binding of NF-κB, which is an important transcription factor for controlling MMP-2/9 and VEGF gene expression.

Aristolochic acid downregulates monocytic matrix metalloproteinase-9 by inhibiting nuclear factor-κB activation

Aristolochic acid (AA)-associated nephropathy was described as being characterized by a rapid progressive enhancement of interstitial renal fibrosis. Renal tissue fibrosis occurs because of an imbalance of extracellular matrix (ECM) accumulation and matrix metalloproteinase (MMP) activation. Much evidence indicates that inflammatory renal disease including monocyte and mesangial interactions is linked to the development and progression of renal remodeling. In this study, we found that AA showed concentration-dependent inhibition of tumor necrosis factor (TNF)-α-induced MMP-9 activation with an IC(50) value of 6.4±0.5μM in human monocytic THP-1 cells. A similar effect was also noted with different ratios of AAs (types I and II). However, AA had no inhibitory effect on the intact enzymatic activity of MMP-9 at a concentration of 20μM. On the other hand, the level of tissue inhibitor of metalloproteinase (TIMP)-1 was not induced by AA, but it suppressed TNF-α-induced MMP-9 protein and messenger RNA expressions. AA also significantly inhibited TNF-α-induced IκBα degradation. Furthermore, an electrophoretic mobility shift assay and a reported gene study, respectively, revealed that AA inhibited TNF-α-induced NF-κB translocation and activation. In addition, compared to other NF-κB inhibitors, AA exerted significant inhibition of MMP-9 activation and monocyte chemotactic protein-1-directed invasion. From these results, we concluded that AA, a natural compound, inhibits TNF-α-induced MMP-9 in human monocytic cells possibly through the NF-κB signal pathway. These results also imply that AA may be involved in alteration of matrix homeostasis during renal fibrosis in vivo.

Suppression of phorbol-12-myristate-13-acetate-induced tumor cell invasion by piperine via the inhibition of PKCα/ERK1/2-dependent matrix metalloproteinase-9 expression

Piperine is a major component of black pepper, Piper nigrum Linn, used widely in traditional medicine. Several previous studies reported that piperine possesses various beneficial biological activities including antioxidant, anti-tumor and anti-inflammation properties. In the present study, we investigated the inhibitory effects of piperine on tumor invasion and migration and the possible mechanisms involved using human fibrosarcoma HT-1080 cells. We found that piperine suppresses PMA-enhanced matrix metalloproteinase-9 (MMP-9) expression at the protein, mRNA, and transcriptional levels through the suppression of NF-κB and AP-1 activation without changing the level of tissue inhibitor of metalloproteinase (TIMP)-1. Piperine also inhibits PMA-enhanced membrane-type 1 MMP expression without changing the level of tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2. Piperine inhibited PMA-induced NF-κB and c-Jun nuclear translocation, which are upstream of PMA-induced MMP-9 expression and invasion. Furthermore, piperine strongly repressed the PMA-induced phosphorylation of ERK, which are dependent on the PKCα pathway. In conclusion, we demonstrated that the anti-invasive effects of piperine may occur through inhibition of PKCα and ERK phosphorylation and reduction of NF-κB and AP-1 activation, leading to down-regulation of MMP-9 expression. Thus, piperine has potential as a potent anti-cancer drug in therapeutic strategies for fibrosarcoma metastasis.

Suppression of EGF-induced tumor cell migration and matrix metalloproteinase-9 expression by capsaicin via the inhibition of EGFR-mediated FAK/Akt, PKC/Raf/ERK, p38 MAPK, and AP-1 signaling

SCOPE

Capsaicin is a cancer-suppressing agent. The aim of our study was to determine the effect of capsaicin on tumor invasion and migration; the possible mechanisms involved in this inhibition were investigated in human fibrosarcoma cells.

METHODS AND RESULTS

We employed invasion, migration and gelatin zymography assays to characterize the effect of capsaicin on HT-1080 cells. Transient transfection assays and immunoblot analysis were performed to study its molecular mechanisms of action. Capsaicin inhibited the epidermal growth factor (EGF)-induced activation of matrix metalloproteinase (MMP)-9 and MMP-2, and further inhibited cell invasion and migration. Capsaicin decreased the EGF-induced expression of MMP-9, MMP-2, and MT1-MMP, but did not alter TIMP-1 and TIMP-2 levels. Capsaicin suppressed EGF-induced c-Jun and c-Fos nuclear translocation, and also abrogated the EGF-induced phosphorylation of EGF receptor (EGFR), focal adhesion kinase (FAK), protein kinase C (PKC), phosphatidylinositol 3-Kinase (PI3K)/Akt, extracellular regulated kinase (ERK)1/2, and JNK1/2, an upstream modulator of AP-1. Furthermore, the EGFR inhibitor inhibited EGF-induced MMP-9 expression, as well as AP-1 activity and cell migration.

CONCLUSION

Capsaicin inhibited the EGF-induced invasion and migration of human fibrosarcoma cells via EGFR-dependent FAK/Akt, PKC/Raf/ERK, p38 mitogen-activated protein kinase (MAPK), and AP-1 signaling, leading to the down-regulation of MMP-9 expression. These results indicate the role of capsaicin as a potent anti-metastatic agent, which can markedly inhibit the metastatic and invasive capacity of fibrosarcoma cells.

Metallothionein-2A overexpression increases the expression of matrix metalloproteinase-9 and invasion of breast cancer cells

The overexpression of metallothionein-2A (MT-2A) is frequently observed in invasive human breast tumors and has been linked with more aggressive breast cancers. MT-2A overexpression led to the induction of MDA-MB-231 breast cancer cell migratory and invasive abilities. The reduction of MT-2A expression through small interfering RNA (siRNA) targeting MT-2A in invasive MDA-MB-231 cells completely inhibited both cell invasion and migration. In addition, the expression of matrix metalloproteinase-9 (MMP-9) and the transcriptional activity of AP-1 and NF-κB were upregulated by MT-2A overexpression. Collectively, our results provide the first demonstration that MT-2A promotes breast cancer cell invasion by upregulating MMP-9 via AP-1 and NF-κB activation. Furthermore, we found that MT-2A silencing can inhibit breast cancer invasiveness.

Acute stress elicited by bungee jumping suppresses human innate immunity

Although a relation between diminished human immunity and stress is well recognized both within the general public and the scientific literature, the molecular mechanisms by which stress alters immunity remain poorly understood. We explored a novel model for acute human stress involving volunteers performing a first-time bungee jump from an altitude of 60 m and exploited this model to characterize the effects of acute stress in the peripheral blood compartment. Twenty volunteers were included in the study; half of this group was pretreated for 3 d with the β-receptor blocking agent propranolol. Blood was drawn 2 h before, right before, immediately after and 2 h after the jump. Plasma catecholamine and cortisol levels increased significantly during jumping, which was accompanied by significantly reduced ex vivo inducibility of proinflammatory cytokines as well as activation of coagulation and vascular endothelium. Kinome profiles obtained from the peripheral blood leukocyte fraction contained a strong noncanonical glucocorticoid receptor signal transduction signature after jumping. In apparent agreement, jumping down-regulated Lck/Fyn and cellular innate immune effector function (phagocytosis). Pretreatment of volunteers with propranolol abolished the effects of jumping on coagulation and endothelial activation but left the inhibitory effects on innate immune function intact. Taken together, these results indicate that bungee jumping leads to a catecholamine-independent immune suppressive phenotype and implicate noncanonical glucocorticoid receptor signal transduction as a major pathway linking human stress to impaired functioning of the human innate immune system.

Transforming growth factor-β1 induces matrix metalloproteinase-9 and cell migration in astrocytes: roles of ROS-dependent ERK- and JNK-NF-κB pathways

BACKGROUND

Transforming growth factor-β (TGF-β) and matrix metalloproteinases (MMPs) are the multifunctional factors during diverse physiological and pathological processes including development, wound healing, proliferation, and cancer metastasis. Both TGF-β and MMPs have been shown to play crucial roles in brain pathological changes. Thus, we investigated the molecular mechanisms underlying TGF-β1-induced MMP-9 expression in brain astrocytes.

METHODS

Rat brain astrocytes (RBA-1) were used. MMP-9 expression was analyzed by gelatin zymography and RT-PCR. The involvement of signaling molecules including MAPKs and NF-κB in the responses was investigated using pharmacological inhibitors and dominant negative mutants, determined by western blot and gene promoter assay. The functional activity of MMP-9 was evaluated by cell migration assay.

RESULTS

Here we report that TGF-β1 induces MMP-9 expression and enzymatic activity via a TGF-β receptor-activated reactive oxygen species (ROS)-dependent signaling pathway. ROS production leads to activation of extracellular signal-regulated kinase 1/2 (ERK1/2) and c-Jun-N-terminal kinase (JNK) and then activation of the NF-κB transcription factor. Activated NF-κB turns on transcription of the MMP-9 gene. The rat MMP-9 promoter, containing a NF-κB cis-binding site, was identified as a crucial domain linking to TGF-β1 action.

CONCLUSIONS

Collectively, in RBA-1 cells, activation of ERK1/2- and JNK-NF-κB cascades by a ROS-dependent manner is essential for MMP-9 up-regulation/activation and cell migration induced by TGF-β1. These findings indicate a new regulatory pathway of TGF-β1 in regulating expression of MMP-9 in brain astrocytes, which is involved in physiological and pathological tissue remodeling of central nervous system.

Calmodulin kinase II-dependent transactivation of PDGF receptors mediates astrocytic MMP-9 expression and cell motility induced by lipoteichoic acid

Background

Lipoteichoic acid (LTA) is a component of Gram-positive bacterial cell walls, which has been found to be elevated in cerebrospinal fluid of patients suffering from meningitis. Moreover, matrix metalloproteinases (MMPs), MMP-9 especially, have been observed in patients with brain inflammatory diseases and may contribute to brain disease pathology. However, the molecular mechanisms underlying LTA-induced MMP-9 expression in brain astrocytes remain unclear.

Objective

The goal of this study was to examine whether LTA-induced cell migration is mediated by calcium/calmodulin (CaM)/CaM kinase II (CaMKII)-dependent transactivation of the PDGFR pathway in rat brain astrocytes (RBA-1 cells).

Methods

Expression and activity of MMP-9 induced by LTA was evaluated by zymographic, western blotting, and RT-PCR analyses. MMP-9 regulatory signaling pathways were investigated by treatment with pharmacological inhibitors or using dominant negative mutants or short hairpin RNA (shRNA) transfection, and chromatin immunoprecipitation (ChIP)-PCR and promoter activity reporter assays. Finally, we determined the cell functional changes by cell migration assay.

Results

The data show that c-Jun/AP-1 mediates LTA-induced MMP-9 expression in RBA-1 cells. Next, we demonstrated that LTA induces MMP-9 expression via a calcium/CaM/CaMKII-dependent transactivation of PDGFR pathway. Transactivation of PDGFR led to activation of PI3K/Akt and JNK1/2 and then activated c-Jun/AP-1 signaling. Activated-c-Jun bound to the AP-1-binding site of the MMP-9 promoter, and thereby turned on transcription of MMP-9. Eventually, up-regulation of MMP-9 by LTA enhanced cell migration of astrocytes.

Conclusions

These results demonstrate that in RBA-1 cells, activation of c-Jun/AP-1 by a CaMKII-dependent PI3K/Akt-JNK activation mediated through transactivation of PDGFR is essential for up-regulation of MMP-9 and cell migration induced by LTA. Understanding the regulatory mechanisms underlying LTA-induced MMP-9 expression and functional changes in astrocytes may provide a new therapeutic strategy for Gram-positive bacterial infections in brain disorders.

Acteoside inhibits PMA-induced matrix metalloproteinase-9 expression via CaMK/ERK- and JNK/NF-κB-dependent signaling

SCOPE

Acteoside, an active phenylethanoid glycoside found in bitter tea and many medicinal plants, displays chemopreventive properties. The aim of our study was to determine the effect of acteoside on tumor invasion and migration; the possible mechanisms involved in this inhibition were investigated in human fibrosarcoma HT-1080 cells.

METHODS AND RESULTS

We employed invasion, migration and gelatin zymography assays to characterize the effect of acteoside on HT-1080 cells. Transient transfection assays were performed to investigate gene promoter activities, and immunoblot analysis to study its molecular mechanisms of action. We found that acteoside suppresses phorbol-12-myristate-13-acetate (PMA)-enhanced matrix metalloproteinase-9 (MMP-9) expression at the protein, mRNA, and transcriptional levels through the suppression of NF-κB activation. In addition, acteoside repressed the PMA-induced phosphorylation of ERK1/2 (ERK, extracellular regulated kinase) and JNK1/2. Further, we found that acteoside decreased the PMA-induced influx of Ca(2+) and repressed PMA-induced calmodulin-dependent protein kinase (CaMK) phosphorylation. Furthermore, treatment with BAPTA/AM, W7, or capsazepine markedly decreased PMA-induced MMP-9 secretion and cell migration, as well as ERK and JNK/NF-κB activation.

CONCLUSION

Acteoside inhibited PMA-induced invasion and migration of human fibrosarcoma cells via Ca(2+) -dependent CaMK/ERK and JNK/NF-κB-signaling pathways. Acteoside therefore has the potential to be a potent anticancer agent in therapeutic strategies for fibrosarcoma metastasis.

Metformin blocks migration and invasion of tumour cells by inhibition of matrix metalloproteinase-9 activation through a calcium and protein kinase Calpha-dependent pathway: phorbol-12-myristate-13-acetate-induced/extracellular signal-regulated kinase/activator protein-1

BACKGROUND AND PURPOSE

Population studies have revealed that treatment with the anti-diabetic drug metformin is significantly associated with reduced cancer risk, but the underlying mode of action has not been elucidated. The aim of our study was to determine the effect of metformin on tumour invasion and migration, and the possible mechanisms, using human fibrosarcoma HT-1080 cells.

EXPERIMENTAL APPROACH

We employed invasion, migration and gelatin zymography assays to characterize the effect of metformin on HT-1080 cells. Transient transfection assays were performed to gene promoter activities, and immunoblot analysis to study its molecular mechanisms of action.

KEY RESULTS

Metformin inhibited migration and invasion by HT-1080 cells at sub-toxic concentrations. In these cells, metformin also suppressed phorbol-12-myristate-13-acetate (PMA)-enhanced levels of matrix metalloproteinases-9 (MMP-9) protein, mRNA and transcription activity through suppression of activator protein-1 (AP-1) activation. In addition, metformin strongly repressed the PMA-induced phosphorylation of extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and protein kinase C(PKC)alpha, whereas the phosphorylation of p38 mitogen-activated protein kinase was not affected by metformin. Metformin decreased the PMA-induced Ca(2+) influx. Furthermore, treatment with an intracellular Ca(2+) chelator (BAPTA-AM) or a selective calmodulin antagonist (W7) markedly decreased PMA-induced MMP-9 secretion and cell migration, as well as activation of ERK and JNK/AP-1.

CONCLUSIONS AND IMPLICATIONS

Metformin inhibited PMA-induced invasion and migration of human fibrosarcoma cells via Ca(2+)-dependent PKCalpha/ERK and JNK/AP-1-signalling pathways. Metformin therefore has the potential to be a potent anti-cancer drug in therapeutic strategies for fibrosarcoma metastasis.

Differential modulation of the cytokine-induced MMP-9/TIMP-1 protease-antiprotease system by the mTOR inhibitor rapamycin

The mTOR-inhibitor rapamycin is a potent drug used in many immunosuppressive and antiinflammatory therapeutic regimes. In renal transplantation despite its beneficial roles rapamycin in some cases can promote renal fibrosis in the kidney but the underlying mechanisms are unknown. In this study, we tested for possible modulatory effects of rapamycin on the cytokine-triggered matrix metalloproteinase 9 (MMP-9)/tissue inhibitor of metalloproteinase (TIMP)-1 protease-antiprotease system which is critically involved in renal inflammation and fibrosis. Treatment of rat mesangial cells (MC) with rapamycin dose-dependently reduced the interleukin 1β (IL-1β)-triggered increase in gelatinolytic levels as demonstrated by zymography. The reduction in the extracellular MMP-9 content by rapamycin coincided with an attenuation in cytokine-induced steady-state MMP-9 mRNA levels. Conversely, rapamycin caused a dose-dependent increase in cytokine-evoked TIMP-1 expression in a Smad binding element (SBE)-dependent manner. Surprisingly, the attenuation of MMP-9 mRNA levels by rapamycin is accompanied by a potentiation of IL-1β-induced MMP-9 promoter activity in which the stimulatory effects by rapamycin are mainly attributed to a proximal AP-1 binding site. Furthermore, the rapamycin-dependent potentiation of MMP-9 expression is accompanied by an amplification of cytokine-triggered activities of nuclear factor κB (NF-κB) and activator protein 1 (AP-1) transcription factors. Importantly, rapamycin-triggered increase in MMP-9 promoter activity is fully impaired when we used a MMP-9 reporter construct which is under the additional control of the 3' untranslated region (3'-UTR) of MMP-9. Collectively, these data imply that rapamycin inhibits the cytokine-induced MMP-9 mainly through posttranscriptional events and thereby exerts profibrotic activities.