Regulation Of Matrix Metalloproteinases Activity Research Articles

A Novel Strategy for the Treatment of Aneurysms: Inhibition of MMP-9 Activity through the Delivery of TIMP-1 Encoding Synthetic mRNA into Arteries.

Aneurysms pose life-threatening risks due to the dilatation of the arteries and carry a high risk of rupture. Despite continuous research efforts, there are still no satisfactory or clinically effective pharmaceutical treatments for this condition. Accelerated inflammatory processes during aneurysm development lead to increased levels of matrix metalloproteinases (MMPs) and destabilization of the vessel wall through the degradation of the structural components of the extracellular matrix (ECM), mainly collagen and elastin. Tissue inhibitors of metalloproteinases (TIMPs) directly regulate MMP activity and consequently inhibit ECM proteolysis. In this work, the synthesis of TIMP-1 protein was increased by the exogenous delivery of synthetic TIMP-1 encoding mRNA into aortic vessel tissue in an attempt to inhibit MMP-9. In vitro, TIMP-1 mRNA transfection resulted in significantly increased TIMP-1 protein expression in various cells. The functionality of the expressed protein was evaluated in an appropriate ex vivo aortic vessel model. Decreased MMP-9 activity was detected using in situ zymography 24 h and 48 h post microinjection of 5 µg TIMP-1 mRNA into the aortic vessel wall. These results suggest that TIMP-1 mRNA administration is a promising approach for the treatment of aneurysms.

TIMP-1 Protects Tight Junctions of Brain Endothelial Cells From MMP-Mediated Degradation.

The blood-brain barrier (BBB) plays a critical role in central nervous system homeostasis, and the integrity ofBBB is disrupted in many neurodegenerative diseases. Matrix metalloproteinases (MMPs) degrade the tight junctions (TJs) of endothelial cells and basement membrane components essential to BBB integrity, which leads to increased BBB permeability and allows inflammatory cells and neurotoxic substances to enter the brain. Tissue inhibitors of metalloproteinases (TIMPs), endogenous inhibitors of MMPs, regulate MMP activity, thereby maintaining BBB integrity. The disruptive impacts of MMP-3 and MMP-9 on BBB and protective effect of TIMP-1 were investigated in a simplified in vitro model of the BBB, which was generated using rat brain microvascular endothelial cells (RBMEC). The main features of BBB formation, including permeability and the trans-endothelial electrical resistance (TEER), were monitored over time after the addition of MMP-3 and MMP-9 and their complexes with TIMP-1 inhibitor. Our results indicated that MMP-3 and MMP-9 caused a dose-dependent disruption of the BBB, with 1.5µM MMPs resulting in an over threefold increase in permeability, while TIMP-1 inhibition protected the integrity of the BBB model and recovered TEER and permeability of RBMECs. The disruption and recovery of tight junction proteins of RBMECs after MMP and TIMP treatment were also detected using fluorescent microscopy. MMP-9 and MMP-3 disrupt the BBB bydegrading tight junctions in endothelial cells, and TIMP-1 could inhibit the disruptive effect of MMP-3 and MMP-9 by showing potential as therapeutic proteinagainst MMP-related diseases where BBB disruption plays a role.

Gold Nanorods Inhibit Tumor Metastasis by Regulating MMP-9 Activity: Implications for Radiotherapy.

Dysregulation of matrix metalloproteinase (MMP) is strongly implicated in tumor invasion and metastasis. Nanomaterials can interact with proteins and have impacts on protein activity, which provides a potential strategy for inhibiting tumor invasion and metastasis. However, the regulation of MMP activity by nanomaterials has not been fully determined. Herein, we have found that gold nanorods (Au NRs) are able to induce the change of the secondary structure of MMP-9 and thereby inhibit their activity. Interestingly, the inhibition of MMP-9 activity is highly dependent on the aspect ratio of Au NRs, and an aspect ratio of 3.3 shows the maximum inhibition efficiency. Molecular dynamics simulations combined with mathematical statistics algorithm reveal the binding behaviors and interaction modes of MMP-9 with Au NRs in atomic details and disclose the mechanism of aspect ratio-dependent inhibition effect of Au NRs on MMP-9 activity. Au NRs with an aspect ratio of 3.3 successfully suppress the X-ray-activated invasion and metastasis of tumor by inhibiting MMP-9 activity. Our findings provide important guidance for the modulation of MMP-9 activity by tuning key parameters of nanomaterials and demonstrate that gold nanorods could be developed as potential MMP inhibitors.

Matrix metalloproteinases in extracellular matrix remodeling: molecular, cellular and tissue aspects

Matrix metalloproteinases are an integral component of the organ-specific tissue microenvironment, primarily participating in the regulation of the state of the integrative-buffer metabolic environment, tissue remodeling, morphogenesis and immunogenesis, and the genesis of pathological vascular diseases. Therefore, issues related to regulation of matrix metalloproteinase activity under altered gravity are a matter of high urgency for space biomedicine. The review highlights aspects of regulation of matrix metalloproteinase activity under altered gravity. The study results included in the current systematic review were searched for in independent literature sources in the PubMed and Cochrane databases, Google Scholar and the NASA Technical Reports Server. A variety of stress factors associated with space flights, in particular, exposure to radiation, enhances the expression of transforming growth factor beta and matrix metalloproteinases-2. Experimental data obtained during several flights demonstrate that microgravity affects the architecture of cells and increases the expression of matrix metalloproteinases-1 and interleukin-6. Microgravity reduces the expression of collagen I, and the level of fibrillar collagen, which affects the mechanical properties of the intracellular matrix. Matrix metalloproteinases -1, -3, -10 demonstrated an increased activity in flight samples of 16-week-old female C57BL/6J mice (n = 8) during 15 days aboard the Space Shuttle Discovery, the STS-131 mission, compared to ground control (12.94; 2.98 and 16.85 times, respectively, P<0.05), while matrix metalloproteinases inhibitors – tissue metalloproteinase inhibitors-1, -2, and -3, demonstrated no statistically significant changes in gene expression. There were determined significant differences in the gene expression profiles in the lungs of animals of the space flight and ground control groups. The genes that revealed more than doubled expression were CTGF, MMP-2, NACM1, SPARC, SPOCK1 and TIMP-3, while the genes with the greatest decrease in expression were LAMA1, MMP-3, MMP-7, MMP-13, VCAM-1, and SELE.

Structural and computational investigation of MMP‐3 affinity improvements with an engineered TIMP‐1 inhibitor

Matrix metalloproteinases (MMPs) are a family of zinc‐dependent endopeptidases that function to mediate tissue remodeling; however, they are also implicated in pathological conditions such as cancer, inflammatory and degenerative diseases. There are 23 human MMPs and significant sequence and structural homology exists among them and with other metalloproteinases. This represents a substantial challenge in developing therapeutically viable selective inhibitors due to off‐target effects. Tissue inhibitors of metalloproteinases (TIMPs) are a family of four endogenous protein protease inhibitors that regulate MMP activity. Our lab and others have utilized TIMPs as scaffolds, engineering them to selectively target specific MMPs for potential therapeutic applications. We previously employed a yeast surface display platform to identify TIMP‐1 variants possessing enhanced MMP‐3 affinity. In the current study, we used structures of MMP‐3 co‐crystallized with either WT TIMP‐1 or an engineered TIMP‐1 variant as seeds for molecular dynamics simulations. Simulations were also conducted on unbound WT and engineered TIMP‐1 to examine MMP‐independent dynamics that distinguish the engineered variant. The simulation data were analyzed with root‐mean‐square deviation/fluctuation, time‐dependent secondary structure, temporally resolved hydrogen bonding, conformational clustering, and dynamical network algorithms to discern structural and dynamical determinants of the increased affinity. Key observations that demonstrate the increased effectiveness of engineered TIMP‐1 as an MMP‐3 inhibitor were secondary structural changes in the MMP‐binding loops in proximity to mutations, attenuated global and mutation‐adjacent dynamics, decreased conformational dynamics, and increased persistence of MMP‐3‐compatible conformations. There were also indications of greater interdomain cooperativity within the engineered TIMP‐1 variant: increased interdomain hydrogen bonding, coordinated motions of the N‐terminal region with the C‐terminal domain, and increased intercommunity information flow/motion transfer. From these observations, we hypothesize the increased interdomain interactions represent a mechanism of dynamical stabilization such that mainly cooperative motion between domains presides, rather than random independent motions. Our findings suggest propagated motions between domains may influence the MMP affinity of TIMPs. Furthermore, these data suggest future strategies to design next‐generation mutant TIMP libraries by targeting regions dynamically coupled to the MMP binding loops for variation, thus exploiting natural protein dynamics to achieve desired selectivity.

Matrix metalloproteinases and their inhibitors in pediatric severe acute pancreatitis.

BackgroundAcute pancreatitis (AP) is increasing in incidence in adult and pediatric patients. Identification of patients at high risk for progression to severe acute pancreatitis (SAP) is crucial, as it can lead to increased mortality and health system cost. Matrix metalloproteinases (MMPs) are endopeptidases which degrade extracellular matrix proteins and increase activity of pro-inflammatory cytokines. Tissue inhibitors of metalloproteinases (TIMPs) regulate MMP activity. Prior limited studies of MMPs and TIMPs have found some to be associated with development of SAP. The aim of this study was to further investigate the role of MMPs and TIMPs in detecting pediatric patients at risk for developing moderately severe AP or SAP.MethodsPlasma samples were prospectively collected for patients <21 years of age presenting with AP between November 2015 and October 2019, along with healthy controls. Bead-based multiplex assays were utilized to test levels of 12 MMPs and TIMPs.ResultsSamples were collected from 7 subjects who developed SAP, 7 with moderately severe AP, 45 with mild AP and 44 healthy controls. MMP-9 (p = 0.04) and TIMP-1 (p = 0.01) levels were significantly higher in SAP patients. A multivariable logistic regression model using MMP-9 and TIMP-1 predicted SAP (AUROC 0.87, 95% CI 0.76–0.98).ConclusionWe have demonstrated that MMP9 and TIMP1 levels are increased at AP presentation in pediatric patients who developed SAP during the course of illness. Further studies are needed to validate the use of MMPs and TIMPs as predictive tools for development of SAP in pediatric pancreatitis.

Four potential microRNAs affect the progression of pancreatic ductal adenocarcinoma by targeting MET via the PI3K/AKT signaling pathway.

Pancreatic ductal adenocarcinoma (PDAC) is the most common tumor subtype of pancreatic cancer, which exhibits poor patient prognosis due to the lack of effective biomarkers in the diagnosis and treatment. The present study aimed to identify the potential biomarkers of PDAC carcinogenesis and progression using three microarray datasets, GSE15471, GSE16515 and GSE28735, which were downloaded from the Gene Expression Omnibus database. The datasets were analyzed to screen out differentially expressed genes (DEGs) in PDAC tissues and adjacent normal tissues. A total of 143 DEGs were identified, including 132 upregulated genes and 11 downregulated genes. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes functional and signaling pathway enrichment analyses were performed on the DEGs, and the Search Tool for the Retrieval of Interacting Genes/Proteins database was used to construct a protein-protein interaction network. The main functions of DEGs include extracellular matrix degradation, and regulation of matrix metalloproteinase activity and the PI3K-Akt signaling pathway. The five hub genes were subsequently screened using Cytoscape software, and survival analysis demonstrated that abnormal expression levels of the hub genes was associated with poor disease-free survival and overall survival. Biological experiments were performed to confirm whether mesenchymal-to-epithelial transition (MET) factors promote the proliferation, migration and invasion of PDAC cells via the PI3K/AKT signaling pathway. In addition, six MET-targeted microRNAs (miRNAs) were identified, four of which had conserved binding sites with MET. Based on the signaling pathway enrichment analysis of these miRNAs, it is suggested that they can affect the progression of PDAC by targeting MET via the PI3K/AKT signaling pathway. In conclusion, the hub genes and miRNAs that were identified in the present study contribute to the molecular mechanisms of PDAC carcinogenesis and progression. They also provide candidate biomarkers for early diagnosis and treatment of patients with PDAC.

The Role of Matrix Metalloproteinases in Periodontal Disease.

This review provides a detailed description of matrix metalloproteinases (MMPs), focusing on those that are known to have critical roles in bone and periodontal disease. Periodontal disease is an inflammatory process initiated by anaerobic bacteria, which promote the host immune response in the form of a complex network of molecular pathways involving proinflammatory mediators such as cytokines, growth factors, and MMPs. MMPs are a family of 23 endopeptidases, collectively capable of degrading virtually all extracellular matrix (ECM) components. This study critically discusses the available research concerning the involvement of the MMPs in periodontal disease development and progression and presents possible therapeutic strategies. MMPs participate in morphogenesis, physiological tissue turnover, and pathological tissue destruction. Alterations in the regulation of MMP activity are implicated in the manifestation of oral diseases, and MMPs comprise the most important pathway in tissue destruction associated with periodontal disease. MMPs can be considered a risk factor for periodontal disease, and measurements of MMP levels may be useful markers for early detection of periodontitis and as a tool to assess prognostic follow-ups. Detection and inhibition of MMPs could, therefore, be useful in periodontal disease prevention or be an essential part of periodontal disease therapy, which, considering the huge incidence of the disease, may greatly improve oral health globally.

Elevated plasma levels of TIMP-3 are associated with a higher risk of acute respiratory distress syndrome and death following severe isolated traumatic brain injury

BackgroundComplications after injury, such as acute respiratory distress syndrome (ARDS), are common after traumatic brain injury (TBI) and associated with poor clinical outcomes. The mechanisms driving non-neurologic organ dysfunction after...

Multimodal Molecular Imaging Demonstrates Myeloperoxidase Regulation of Matrix Metalloproteinase Activity in Neuroinflammation.

Myeloperoxidase (MPO) has paradoxically been found to be able to both activate matrix metalloproteinases (MMPs) as well as inhibit MMPs. However, these regulatory effects have not yet been observed in vivo, and it is unclear which pathway is relevant in vivo. We aim to track MPO regulation of MMP activity in living animals in neuroinflammation. Mice induced with experimental autoimmune encephalomyelitis (EAE), a mouse model of neuroinflammation and multiple sclerosis, were treated with either the MPO-specific inhibitor 4-aminobenzoic acid hydrazide or saline as control. Mice underwent concurrent magnetic resonance imaging (MRI) with the MPO-specific molecular imaging agent MPO-Gd and fluorescence molecular tomography (FMT) with the MMP-targeting agent MMPsense on day 12 after induction. Biochemical and histopathological correlations were performed. Utilizing concurrent MRI and FMT imaging, we found reduced MMP activity in the brain with MPO inhibition, demonstrating MPO activity positively regulates MMP activity in vivo. In vivo MMPSense activation and MMP-9 activity correlated with MPO-Gd+ lesion volume and disease severity. This was corroborated by in vitro assays and histopathological analyses that showed MMP activity and MMP-9+ cells correlated with MPO activity and MPO+ cells. In conclusion, multimodal molecular imaging demonstrates for the first time MPO regulation of MMP activity in living animals. This approach could serve as a model to study the interactions of other biologically interesting molecules in living organisms.

Interleukin-17 regulates matrix metalloproteinase activity in human pulmonary tuberculosis.

Tuberculosis (TB) is characterized by extensive pulmonary matrix breakdown. Interleukin‐17 (IL‐17) is key in host defence in TB but its role in TB‐driven tissue damage is unknown. We investigated the hypothesis that respiratory stromal cell matrix metalloproteinase (MMP) production in TB is regulated by T‐helper 17 (TH‐17) cytokines. Biopsies of patients with pulmonary TB were analysed by immunohistochemistry (IHC), and patient bronchoalveolar lavage fluid (BALF) MMP and cytokine concentrations were measured by Luminex assays. Primary human airway epithelial cells were stimulated with conditioned medium from human monocytes infected with Mycobacterium tuberculosis (Mtb) and TH‐17 cytokines. MMP secretion, activity, and gene expression were determined by ELISA, Luminex assay, zymography, RT‐qPCR, and dual luciferase reporter assays. Signalling pathways were examined using phospho‐western analysis and siRNA. IL‐17 is expressed in TB patient granulomas and MMP‐3 is expressed in adjacent pulmonary epithelial cells. IL‐17 had a divergent, concentration‐dependent effect on MMP secretion, increasing epithelial secretion of MMP‐3 (p < 0.001) over 72 h, whilst decreasing that of MMP‐9 (p < 0.0001); mRNA levels were similarly affected. Both IL‐17 and IL‐22 increased fibroblast Mtb‐dependent MMP‐3 secretion but IL‐22 did not modulate epithelial MMP‐3 expression. Both IL‐17 and IL‐22, but not IL‐23, were significantly up‐regulated in BALF from TB patients. IL‐17‐driven MMP‐3 was dependent on p38 MAP kinase and the PI3K p110α subunit. In summary, IL‐17 drives airway stromal cell‐derived MMP‐3, a mediator of tissue destruction in TB, alone and with monocyte‐dependent networks in TB. This is regulated by p38 MAP kinase and PI3K pathways. © 2017 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

VANGL2 interacts with integrin αv to regulate matrix metalloproteinase activity and cell adhesion to the extracellular matrix

Planar cell polarity (PCP) proteins are implicated in a variety of morphogenetic processes including embryonic cell migration and potentially cancer progression. During zebrafish gastrulation, the transmembrane protein Vang-like 2 (VANGL2) is required for PCP and directed cell migration. These cell behaviors occur in the context of a fibrillar extracellular matrix (ECM). While it is thought that interactions with the ECM regulate cell migration, it is unclear how PCP proteins such as VANGL2 influence these events. Using an in vitro cell culture model system, we previously showed that human VANGL2 negatively regulates membrane type-1 matrix metalloproteinase (MMP14) and activation of secreted matrix metalloproteinase 2 (MMP2). Here, we investigated the functional relationship between VANGL2, integrin αvβ3, and MMP2 activation. We provide evidence that VANGL2 regulates cell surface integrin αvβ3 expression and adhesion to fibronectin, laminin, and vitronectin. Inhibition of MMP14/MMP2 activity suppressed the cell adhesion defect in VANGL2 knockdown cells. Furthermore, our data show that MMP14 and integrin αv are required for increased proteolysis by VANGL2 knockdown cells. Lastly, we have identified integrin αvβ3 as a novel VANGL2 binding partner. Together, these findings begin to dissect the molecular underpinnings of how VANGL2 regulates MMP activity and cell adhesion to the ECM.

Regulation of Matrix Metalloproteinase-2 Activity by COX-2-PGE2-pAKT Axis Promotes Angiogenesis in Endometriosis.

Endometriosis is characterized by the ectopic development of the endometrium which relies on angiogenesis. Although studies have identified the involvement of different matrix metalloproteinases (MMPs) in endometriosis, no study has yet investigated the role of MMP-2 in endometriosis-associated angiogenesis. The present study aims to understand the regulation of MMP-2 activity in endothelial cells and on angiogenesis during progression of ovarian endometriosis. Histological and biochemical data showed increased expressions of vascular endothelial growth factor (VEGF), VEGF receptor-2, cycloxygenase (COX)-2, von Willebrand factor along with angiogenesis during endometriosis progression. Women with endometriosis showed decreased MMP-2 activity in eutopic endometrium as compared to women without endometriosis. However, ectopic ovarian endometrioma showed significantly elevated MMP-2 activity with disease severity. In addition, increased MT1MMP and decreased tissue inhibitors of metalloproteinases (TIMP)-2 expressions were found in the late stages of endometriosis indicating more MMP-2 activation with disease progression. In vitro study using human endothelial cells showed that prostaglandin E2 (PGE2) significantly increased MMP-2 activity as well as tube formation. Inhibition of COX-2 and/or phosphorylated AKT suppressed MMP-2 activity and endothelial tube formation suggesting involvement of PGE2 in regulation of MMP-2 activity during angiogenesis. Moreover, specific inhibition of MMP-2 by chemical inhibitor significantly reduced cellular migration, invasion and tube formation. In ovo assay showed decreased angiogenic branching upon MMP-2 inhibition. Furthermore, a significant reduction of lesion numbers was observed upon inhibition of MMP-2 and COX-2 in mouse model of endometriosis. In conclusion, our study establishes the involvement of MMP-2 activity via COX-2-PGE2-pAKT axis in promoting angiogenesis during endometriosis progression.

How, with whom and when: an overview of CD147-mediated regulatory networks influencing matrix metalloproteinase activity.

Matrix metalloproteinases (MMPs) comprise a family of 23 zinc-dependent enzymes involved in various pathologic and physiologic processes. In cancer, MMPs contribute to processes from tumour initiation to establishment of distant metastases. Complex signalling and protein transport networks regulate MMP synthesis, cell surface presentation and release. Earlier attempts to disrupt MMP activity in patients have proven to be intolerable and with underwhelming clinical efficacy; thus targeting ancillary proteins that regulate MMP activity may be a useful therapeutic approach. Extracellular matrix metalloproteinase inducer (EMMPRIN) was originally characterized as a factor present on lung cancer cells, which stimulated collagenase (MMP-1) production in fibroblasts. Subsequent studies demonstrated that EMMPRIN was identical with several other protein factors, including basigin (Bsg), all of which are now commonly termed CD147. CD147 modulates the synthesis and activity of soluble and membrane-bound [membrane-type MMPs (MT-MMPs)] in various contexts via homophilic/heterophilic cell interactions, vesicular shedding or cell-autonomous processes. CD147 also participates in inflammation, nutrient and drug transporter activity, microbial pathology and developmental processes. Despite the hundreds of manuscripts demonstrating CD147-mediated MMP regulation, the molecular underpinnings governing this process have not been fully elucidated. The present review summarizes our present knowledge of the complex regulatory systems influencing CD147 biology and provides a framework to understand how CD147 may influence MMP activity.

Assessment of Synthetic Matrix Metalloproteinase Inhibitors by Fluorogenic Substrate Assay.

Matrix metalloproteinases (MMPs) are a family of metzincin enzymes that act as the principal regulators and remodelers of the extracellular matrix (ECM). While MMPs are involved in many normal biological processes, unregulated MMP activity has been linked to many detrimental diseases, including cancer, neurodegenerative diseases, stroke, and cardiovascular disease. Developed as tools to investigate MMP function and as potential new therapeutics, matrix metalloproteinase inhibitors (MMPIs) have been designed, synthesized, and tested to regulate MMP activity. This chapter focuses on the use of enzyme kinetics to characterize inhibitors of MMPs. MMP activity is measured via fluorescence spectroscopy using a fluorogenic substrate that contains a 7-methoxycoumarin-4-acetic acid N-succinimidyl ester (Mca) fluorophore and a 2,4-dinitrophenyl (Dpa) quencher separated by a scissile bond. MMP inhibitor (MMPI) potency can be determined from the reduction in fluorescent intensity when compared to the absence of the inhibitor. This chapter describes a technique to characterize a variety of MMPs through enzyme inhibition assays.

Possible mechanism by which renal sympathetic denervation improves left ventricular remodelling after myocardial infarction.

What is the central question of this study? The enzyme system that is responsible for extracellular matrix (ECM) turnover is the matrix metalloproteinases (MMPs), which can be blocked by the tissue inhibitors of MMPs (TIMPs). Whether renal sympathetic denervation (RSD) is able to ameliorate post-myocardial infarction left ventricular remodelling through attenuation of ECM via regulation of MMP activity and/or the MMP-TIMP complex remains unknown. What is the main finding and its importance? Renal sympathetic denervation has therapeutic effects on post-myocardial infarction left ventricular remodelling, probably by attenuating the ECM through regulation of the MMP9-TIMP1 complex in the transforming growth factor-β1 (a profibrotic cytokine that accelerates ECM remodelling after ischaemia) signalling pathway. Whether renal sympathetic denervation (RSD) is able to ameliorate post-myocardial infarction (post-MI) left ventricular (LV) remodelling by attenuation of the extracellular matrix via regulation of matrix metalloproteinase (MMP) activity and/or the MMP-tissue inhibitor of matrix metalloproteinase (TIMP) complex remains unknown. Sixty-five Sprague-Dawley rats were randomly divided into the following four groups: normal (N, n = 15), RSD (RSD, n = 15), myocardial infarction (MI, n = 15) and RSD 3 days after MI (MI3d+RSD, n = 20). The bilateral renal nerves were surgically denervated 3 days after MI had been induced by coronary artery ligation. Left ventricular function was assessed using echocardiography and a Millar catheter at 6 weeks post-MI. Plasma noradrenaline, angiotensin II and aldosterone, collagen volume fraction, transforming growth factor-β1 (TGF-β1), MMP2, MMP9 and TIMP1 in heart tissue were measured 6 weeks after MI. In rats with MI3d+RSD compared with MI rats, RSD improved systolic and diastolic function, resulting in an improvement in ejection fraction (P < 0.05), fractional shortening (P < 0.05) and LV internal dimension in systole (P < 0.05) and diastole (P < 0.05). Additionally, RSD treatment decreased left ventricular end-diastolic pressure (P < 0.05) and increased LV systolic pressure (P < 0.05) and maximal and minimal rate of LV pressure (both P < 0.05). Meanwhile, RSD reduced collagen content (P < 0.01). TIMP1 was upregulated (P < 0.05), whereas MMP2, MMP9 and TGF-β1 were downregulated in the LV of RSD-treated animals (P < 0.05). Renal sympathetic denervation has therapeutic effects on post-MI LV remodelling, probably owing to effects on the extracellular matrix by regulation of the MMP9-TIMP1 balance in the TGF-β1 signalling pathway. Renal sympathetic denervation may be considered as a non-pharmacological approach for the improvement of post-MI cardiac dysfunction.

TIMP-1 couples RhoK activation to IL-1β-induced astrocyte responses

Interleukin-1β (IL-1β) is a pleotropic cytokine known to influence the central nervous system (CNS) responses to injury or infection. IL-1β also directly induces astrocytic expression of tissue inhibitor of metalloproteinases (TIMP)-1, a potent trophic factor and regulator of matrix metalloproteinase activity. In this study, we examined the functional relationship between IL-1β and TIMP-1 and determined that the behavior of astrocytes in response to IL-1β is determined by TIMP-1 expression. Using primary astrocytes from C57Bl/6 mice, we found astrocytes from wildtype (Wt) mice exhibited a robust wound healing response to a scratch wound that was arrested in response to IL-1β. In contrast, TIMP-1 knockout (TIMP-1KO) astrocytes, exhibited minimal response to the scratch wound but an accelerated response following IL-1β-treatment. We also determined that the scratch wound effect in Wt cultures was attenuated by inhibition of Rho kinase but amplified in the TIMP-1KO cultures. We propose that the specific induction of TIMP-1 from astrocytes in response to IL-1β reflects a previously unrecognized physiological relationship where the directionality of astrocytic behavior is determined by the actions of TIMP‑1. These findings may provide additional insight into glial responses in the context of neuropathology where expression of TIMP-1 may vary and astrocytic responses may be impacted by the inflammatory milieu of the CNS.

Hemorrhoids and matrix metalloproteinases: A multicenter study on the predictive role of biomarkers

An association between hemorrhoidal disease and matrix metalloproteinases (MMPs) has been described previously. MMPs regulate extracellular structural proteins and tissue remodeling. Neutrophil gelatinase-associated lipocalin (NGAL) is involved in the regulation of MMP activity. The aim of this work was to study the relationship between tissue immunoreactive levels of MMPs and NGAL and different stages of hemorrhoids. In a multicenter, open-label, prospective study, the population under investigation consisted of 2 groups: group I (with symptomatic hemorrhoids; Goligher grade I-IV) and group II (healthy volunteers). We enrolled 97 patients with hemorrhoids: 21 with grade I hemorrhoids, 37 with grade II, 14 with grade III, and 25 with grade IV. Finally, 90 healthy volunteers (53 males and 37 females; age range, 19-70years; median, 56) were enrolled in group II. Enzyme-linked immunosorbent assay and Western blot analysis revealed greater levels of immunoreactive MMPs and NGAL in all patients with hemorrhoids. We recorded significantly greater levels of MMP-1 and MMP-3 in grade I and II patients compared with control, and greater levels of MMP-3, MMP-7, MMP-8, and MMP-9 in grade III compared with grade II. MMP-9 and NGAL were particularly increased in patients with grade IV especially in case of thrombosed hemorrhoids. These results provide potentially important insights into the understanding of the natural history of hemorrhoids. MMPs and NGAL play a role in development of disease and may represent molecular markers for the complications such as hemorrhoidal thrombosis.

Abstract 5426: Tumor cell surface-associated vacuolar-ATPase ‘a2′ isoform promotes invasion by regulating matrix metalloproteinase activity in ovarian cancer

Abstract In tumors, an acidic pH is an important feature of tumor microenvironment and is a major determinant of tumor metastasis. Efforts are required to identify novel molecular targets that alter this acidic microenvironment to control tumor spread. The Vacuolar-H + −ATPases (V-ATPases) are multi-subunit enzyme complexes that acidify the extracellular space, and activate matrix degrading proteases, thereby promoting tumor invasion. Identifying specific V-ATPase subunit isoforms that are selectively expressed on tumor cells will provide biomarkers and novel targets for V-ATPase inhibition. The ‘a’ subunit of V-ATPase V0 domain is the major pH sensing unit and exists in four different isoforms. The present study describes an elevated expression of V-ATPase ‘a’ subunit isoforms in ovarian cancer. Our findings indicate that among all the ‘a’ subunit isoforms, ‘a2′ is most prominently expressed on the ovarian tumor cell surface. To understand the clinical relevance, the immuno-histochemistry in human OVCA tissues revealed over-expression of V-ATPase-V0a2 compared to control tissues (normal ovary and benign tumors). V-ATPase-V0a2 was upto 4 fold up-regulated at the mRNA level in human OVCA cell lines (A2780, SKOV-3 and TOV-112D) compared to normal ovary epithelia using quantitative reverse transcription-PCR. This up-regulation was also observed at the protein level by western blot and flow cytometry analysis. Immunofluorescence analysis showed selective V0a2 distribution only on tumor cell surface and not on normal ovarian epithelia. Confocal microscopy analysis was performed for understanding the sub-cellular distribution of V-ATPase-V0a2, which confirmed its localization on plasma-membrane and early endosomes. Interestingly, the V0a2 isoform exhibited co-association with cortactin, an F-actin stabilizing protein at leading edges of cancer cells, that are the sites of focal protease release. To understand the possible effect of V0a2 on protease activation, an in vitro targeted inhibition of V-ATPase-V0a2 in OVCA cells using monoclonal anti-V0a2 antibody assay was used. The antibody reduced the matrix metalloproteinase (MMP-9 &amp; MMP-2) activity by 2 fold. Measurement of invasion using an in vitro wound healing assay revealed that inhibition of V-ATPase-V0a2 reduced the invasion capacity and therefore wound healing, in SKOV-3 cells. In conclusion, V-ATPase-V0a2 isoform is highly expressed on ovarian tumor cell surface and is associated with invasion assembly related proteins, therefore playing a critical role in tumor invasion by modulating the activity of matrix-degrading proteases. Our data suggests that the ‘V-ATPase-V0a2 isoform is a potential biomarker in OVCA and isoform specific inhibition of V-ATPase-V0a2 may aid in better clinical outcome of OVCA. Citation Format: Arpita Kulshrestha, Gajendra K. Katara, Sahithi Pamarthy, Safaa A. Ibrahim, Alice Gilman Sachs, Kenneth D. Beaman. Tumor cell surface-associated vacuolar-ATPase ‘a2′ isoform promotes invasion by regulating matrix metalloproteinase activity in ovarian cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5426. doi:10.1158/1538-7445.AM2015-5426

Magnolol reduces UVB-induced photodamage by regulating matrix metalloproteinase activity

In this study, we evaluated the anti-photoaging activity of magnolol in UV-irradiated hairless mice, and hypothesized that magnolol would prevent photoaging in these animals. The inhibitory effect of magnolol on wrinkle formation was determined by analyzing the skin replica, histologically examining the epidermal thickness, and identifying damage to the collagen fibers. The protective effects of magnolol on UVB-induced skin photoaging were examined by determining the level of MMPs and mitogen-activated protein kinases (MAPKs). Exposure to UVB radiation significantly increased skin thickness and wrinkle grade, but magnolol treatment significantly reduced the average length and depth of wrinkles, and this was correlated with the inhibition of collagen fiber loss. The magnolol-treated group had remarkably decreased activity levels of MMP-1, -9, and -13 compared to the corresponding levels in the vehicle-treated UVB-irradiated group. These results indicate that magnolol prevents skin photoaging in UVB-irradiated hairless mice.