Coordinate regulation of matrix metalloproteinase-1 and tissue inhibitor of metalloproteinase-1 expression in human vascular smooth muscle cells

Regulation of matrix metalloproteinases-8, -9 and endogenous tissue inhibitor-1 in oral biofluids during pregnancy and postpartum

OBJECTIVE

During pregnancy, mothers undergoe considerable physiological changes affecting the whole body including periodontal tissues. Susceptibility to gingival inflammation during pregnancy could be mediated by modulation of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs). Therefore, the aim of this study was to investigate salivary and gingival crevicular fluid (GCF) levels of MMPs and TIMPs during the second and third trimester of pregnancy and postpartum.

DESIGN

Saliva and GCF samples were collected from 96 pregnant women (PW) before and after giving birth. The sixty matched non-pregnant women (N-PW) were recruited as a control group and full-mouth periodontal examination was performed. The levels of MMP-8, MMP-9 and TIMP-1 were determined by immunofluorometric and enzyme-linked immunosorbent assays.

RESULTS

The PW group exhibited significantly higher levels of MMP-8 and MMP-9 in their saliva than the N-PW group while corresponding salivary TIMP-1 levels were significantly lower in NPW compared to the postpartum stage. This resulted in significantly higher MMP-8/TIMP-1 and MMP-9/TIMP-1ratio in the saliva from PW before and after birth than in that from N-PW. MMP-8, MMP-9 and TIMP-1 levels were higher in GCF from PW and postpartum than in that from N-PW.

CONCLUSIONS

MMP-8 and MMP-9 levels in saliva and GCF reflect inflammatory burden during pregnancy. They could be used for monitoring the inflammatory state of gingival tissues during pregnancy.

Collagenolytic activity is suppressed in organ-cultured human skin exposed to a gadolinium-based MRI contrast agent

OBJECTIVE

Human skin produces increased amounts of matrix metalloproteinase-1 (MMP-1) when exposed in organ culture to Omniscan, one of the gadolinium-based MRI contrast agents (GBCA). MMP-1, by virtue of its ability to degrade structural collagen, contributes to collagen turnover in the skin. The objective of the present study was to determine whether collagenolytic activity was concomitantly up-regulated with increased enzyme.

MATERIALS AND METHODS

Skin biopsies from normal volunteers were exposed in organ culture to Omniscan. Organ culture fluids obtained from control and treated skin were examined for ability to degrade type I collagen. The same culture fluids were examined for levels of MMP-1, tissue inhibitor of metalloproteinases-1 (TIMP-1), and complexes of MMP-1 and TIMP-1.

RESULTS

Although MMP-1 was increased in culture fluid from Omniscan-treated skin, there was no increase in collagenolytic activity. In fact, collagenolytic activity declined. Increased production of TIMP-1 was also observed in Omniscan-treated skin, and the absolute amount of TIMP-1 was greater than the amount of MMP-1. Virtually all of the MMP-1 was present in MMP-1-TIMP-1 complexes, but the majority of TIMP-1 was not associated with MMP-1. When human dermal fibroblasts were exposed to TIMP-1 (up to 250 ng/mL), no increase in proliferation was observed, but an increase in collagen deposition into the cell layer was seen.

CONCLUSION

Gadolinium-based MRI contrast agent exposure has recently been linked to a fibrotic skin condition in patients with impaired kidney function. The mechanism is unknown. The increase in TIMP-1 production and concomitant reduction in collagenolytic activity demonstrated here could result in decreased collagen turnover and increased deposition of collagen in lesional skin.

In-hospital outcome of patients with acute coronary syndrome: relationship with inflammation and remodeling markers

OBJECTIVES AND METHODS

The present study was designed to evaluate the role of some inflammation [interleukin (IL)-1beta, soluble IL-1 receptor, IL-1 receptor antagonist (IL-1RA), high-sensitivity C-reactive protein (hsCRP) and fibrinogen], and remodeling markers [matrix metalloproteinase (MMP)-9, tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2] in patients with acute coronary syndrome (ACS; 40 patients), or chronic stable angina (CSA; 40 patients) compared to age- and sex-matched healthy controls (20 subjects).

RESULTS

IL-1RA, hsCRP, fibrinogen, MMP-9, and TIMP-1 plasma levels were significantly higher in patients than in controls, whereas soluble IL-1 receptor had an opposite pattern. Among patients with ACS, hsCRP plasma levels were higher in patients with non-ST segment elevation myocardial infarction (NSTEMI) than in those with unstable angina (UA). TIMP-1 plasma levels were higher in those patients with ACS who did not respond to medical therapy (non-responsive unstable angina; NR-UA). A CRP plasma level higher than 0.86 mg/dl had a 91% positive predictive value (PPV) and 63% negative predictive value for NSTEMI (odds ratio = 6.4, 95% confidence interval = 1.5-27.4). TIMP-1 plasma level higher than 21.5 ng/ml had a 100% PPV for patients with NR-UA or NSTEMI. Binary logistic analysis confirmed TIMP-1 levels as being able to predict responsiveness to therapy.

CONCLUSIONS

In conclusion, a different biochemical pattern characterizes ACS patients: those with NR-UA show only an increase of remodeling markers, whereas ACS patients with NSTEMI have an increase of both remodeling and inflammation markers.

Pitavastatin inhibits lysophosphatidic acid-induced proliferation and monocyte chemoattractant protein-1 expression in aortic smooth muscle cells by suppressing Rac-1-mediated reactive oxygen species generation

Lysophosphatidic acid (LPA), a product generated during oxidative modification of low-density lipoprotein (LDL) and a major lipid extracted from human atherosclerotic plaques, has been shown to elicit smooth muscle cell (SMC) proliferation and inflammation, thereby being involved in atherogenesis. Recently, statins, an inhibitor of 3-hydroxy-methylglutaryl coenzyme A (HMG-CoA) reductase, have been reported to reduce the risk of cardiovascular events and slows the progression of atherosclerosis, at least partly, via pleiotropic effects. However, the effect of statin on the LPA-signaling in SMCs remains to be elucidated. In this study, we investigated whether and how pitavastatin could inhibit the LPA-induced proliferation and monocyte chemoattractant protein-1 (MCP-1) expression in cultured human aortic SMCs. LPA dose-dependently increased intracellular reactive oxygen species (ROS) generation in SMCs, which was blocked by diphenylene iodonium (DPI), an inhibitor of NADPH oxidase or pitavastatin. The anti-oxidative property of pitavastatin was prevented by simultaneous treatment of geranylgeranyl pyrophosphate. Furthermore, overexpression of dominant negative Rac-1 mutant was found to inhibit the LPA-induced ROS generation in SMCs. LPA induced Rac-1 activation in SMCs, which was suppressed by pitavastatin or LPA receptor antagonist. Pitavastatin, DPI, and an anti-oxidant N-acetylcysteine inhibited the LPA-induced proliferation and MCP-1 gene expression in SMCs. These results suggest that pitavastatin could block the LPA-induced proliferation and MCP-1 expression in SMCs by suppressing Rac-1-mediated NADPH oxidase-dependent ROS generation. Our present study provides a novel beneficial aspect of pitavastatin; pitavastatin may act as a blocker of the LPA-signaling in SMCs.

The role of MMP-I up-regulation in the increased compliance in muscle-derived stem cell-seeded small intestinal submucosa

We have previously observed that muscle-derived stem cells (MDSC) seeded onto porcine small intestinal submucosa (SIS) increase the mechanical compliance of the engineered tissue construct [Lu SH, Sacks MS, Chung SY, Gloeckner DC, Pruchnic R, Huard J, et al. Biaxial mechanical properties of muscle-derived cell seeded small intestinal submucosa for bladder wall reconstitution. Biomaterials 2005;26(4):443-9]. To date, however, the initial remodeling events which occur when MDSC are seeded onto SIS have yet to be elucidated. One potential mechanism responsible for the observed increase in mechanical compliance is the release of matrix metalloproteinase-I (MMP-I). To investigate this finding, MDSC ( approximately 1x10(6)) were cultured on single-layer SIS cell culture inserts (4.7 cm2) for 1-10 days. MDSC MMP-I activity on SIS in the supernatant at 1, 3, 5, 7, and 10 days was determined using a collagenase assay kit. MMP-I activity of the MDSC/SIS was significantly higher (p<0.0025) after one day in culture compared to specimens collected from subsequent time points and the unseeded control. To further study the initial remodeling events, the impact of MMP-I on mechanical compliance was examined. SIS was incubated with 0.16 U/mL collagenase-I for 3, 4.5, 5, and 24h, then biaxial mechanical testing was performed. After 5h of digestion with collagenase-I, mechanical compliance under 1 MPa peak stress was increased by 7% in the circumferential direction, compared to control SIS. These findings suggest that the release of MMP-I in response to initial seeding on SIS and subsequent breakdown of collagen fibers is the mechanism responsible for an increase in mechanical compliance.

Production of Extracellular Matrix Components in Tissue-Engineered Blood Vessels

Morphology and compliance of tissue-engineered blood vessels (TEBV) are dependent on the culture period and production of extracellular matrix (ECM) components in order to increase the strength of the developing tissue. The aim of the present study was to evaluate the potential of TEBVs to produce an ECM similar to native arteries and veins. Human smooth muscle cells (SMC) were seeded onto the poly(glycolic acid) (PGA) scaffold and placed in bioreactors filled with DMEM supplemented with growth factors. After 6 weeks, the vessels were harvested from the bioreactors and seeded with human endothelial cells at the lumen for another 3 days. Then, the TEBVs were harvested for RNA and protein isolation for further RT-PCR and Western blot. TEBVs had a similar macroscopic appearance to that of native vessels with no visible evidence of the original PGA. Histological and immunohistochemical analyses indicated the presence of high cell density and development of a highly organized structure of ECM. After 6 weeks of culture, there were significantly lower gene expression of SMC-specific markers, such as alpha-actin, caldesmon, and vimentin, and proteoglycans, such as biglycan, decorin, and versican, and other ECM components, such as collagen I and elastin, in TEBVs, with and without pulsatile conditions, compared to that of native arteries. Gene expression of fibronectin was significantly lower in TEBVs grown during pulsatile conditions compared to that of native arteries. No difference was observed in TEBVs grown during non-pulsatile conditions. The presence of alpha-actin, collagen I, decorin, and fibronectin at protein level was demonstrated in TEBVs with and without pulsatile conditions after 6 weeks and in native veins and arteries as well. How this deviation translates into mechanical properties remains to be explored.

Up-regulation and coexpression of MIF and matrix metalloproteinases in human abdominal aortic aneurysms

Abdominal aortic aneurysm (AAA) is a localized dilatation of the arterial wall as a result of extensive breakdown of its structural proteins by matrix metalloproteinases (MMPs). AAA continuously expand and may eventually rupture, causing high mortality rates. The molecular processes underlying expansion and rupture of AAA are only poorly understood. In this study, evidence was sought for a direct involvement of macrophage migration inhibitory factor (MIF) in the pathogenesis of AAA through up-regulating MMPs, with particular reference to macrophages. To this end, expression and cellular localization of MIF were analyzed in human aortic wall samples of stable AAA and ruptured AAA, and compared with control aorta and atherosclerotic aorta (AS). MIF expression was up-regulated in stable AAA and further intensified in ruptured AAA. The increased aneurysmal MIF expression was paralleled by an enhanced expression of specific MMPs, viz. MMP-1, MMP-9, and MMP-12, and by a decrease of their inhibitors. Immunohistochemical analysis of AAA and AS showed MIF protein in endothelial cells, smooth muscle cells (SMCs), macrophages, and T cells. MMP-1 (in SMCs and macrophages) and MMP-9 (in macrophages) were colocalized with MIF at the cellular level in ruptured AAA. The up-regulation of aneurysmal MIF/MMP expression was associated with an increased content of cytotoxic T cells.

The proteome and secretome of human arterial smooth muscle cells

Smooth muscle cells (SMCs) play a crucial role in cardiovascular disorders. A differential proteomic approach should help to elucidate SMC dysfunctions involved in these diseases. With this goal in mind, we plotted the first 2-dimensional (2-D) maps of the proteome and secretome of human arterial smooth muscle cell (ASMC). Intracellular and secreted proteins were extracted from a primary culture of SMCs obtained from patients undergoing coronary artery bypass surgery (n = 11) and separated by 2-dimensional gel electrophoresis. Silver-stained gels were analyzed using Progenesis software. A high level of between-gel reproducibility was obtained, allowing us to generate two protein patterns specific to the ASMC proteome and secretome, respectively. A total of 121 and 40 distinct intracellular and secreted polypeptide spots, corresponding to 83 and 18 different proteins, respectively, were identified by matrix-assisted laser desorption/ionization mass spectrometry. The 2-D reference maps and database resulting from this study confirm that SMCs are involved in a wide range of biological functions. They could constitute a useful tool for a wide range of investigators involved in vascular biology, allowing them to investigate SMC protein changes associated with cardiovascular disorders or environmental stimuli.

Enhanced migration of tissue inhibitor of metalloproteinase overexpressing hepatoma cells is attributed to gelatinases: Relevance to intracellular signaling pathways

AIM: To study the effect of gelatinases (especially MMP-9) on migration of tissue inhibitor of metalloproteinase (TIMP-1) overexpressing hepatoma cells.

METHODS: Wild type HepG2 cells, cells stably transfected with TIMP-1 and TIMP-1 antagonist (MMP-9-H401A, a catalytically inactive matrix metalloproteinase (MMP) which still binds and neutralizes TIMP-1) were incubated in Boyden chambers either with or without Galardin (a synthetic inhibitor of MMP-1, -2, -3, -8, -9) or a specific inhibitor of gelatinases.

RESULTS: Compared to wild type HepG2 cells, the cells overexpressing TIMP-1 showed 115% migration (P<0.05) and the cells overexpressing MMP-9-H401A showed 62% migration (P<0.01). Galardin reduced cell migration dose dependently in all cases. The gelatinase inhibitor reduced migration in TIMP-1 overexpressing cells predominantly. Furthermore, we examined intracellular signal transduction pathways of TIMP-1-dependent HepG2 cells. TIMP-1 deactivates cell signaling pathways of MMP-2 and MMP-9 involving p38 mitogen-activated protein kinase. Specific blockade of the ERK pathway suppresses gelatinase expression either in the presence or absence of TIMP-1.

CONCLUSION: Overexpressing functional TIMP-1- enhanced migration of HepG2-TIMP-1 cells depends on enhanced MMP-activity, especially MMP-9.

TIMP-1 stimulates proliferation of human aortic smooth muscle cells and Ras effector pathways

Tissue inhibitor of metalloproteinases-1 (TIMP-1) is a multifunctional protein, which is found in most tissues and body fluids. Here, we demonstrated that recombinant TIMP-1 but not the synthetic matrix metalloproteinase inhibitor, GM6001, stimulated proliferation of human aortic smooth muscle cells (AoSMC) in a dose-dependent manner. The mitogenic effect was associated with activation of Ras, increased phosphorylation of ERK, and stimulation of cyclin D1 expression. The phosphatidylinositol 3-kinase (PI3K) signaling pathway was also involved since the PI3K inhibitor, LY294002, abolished the TIMP-1-mediated growth stimulation. These data suggest that TIMP-1 activates Ras, which then turns on the ERK and PI3K signaling pathways to promote cell cycle progression of the AoSMC.

Effect of pulse rate on collagen deposition in the tissue-engineered blood vessel

The effect of mechanical stimulation on the development of tissue-engineered blood vessels was examined. In particular, three different rates of radial distension were chosen to produce a nonpulsed environment (0 beats per minute [bpm]), an adult heart rate (90 bpm), and a fetal heart rate (165 bpm). Engineered vessels were cultured for an average of 7 weeks. Vessel walls were then analyzed for collagen content and distribution. In addition, extracellular matrix remodeling was assessed through measurement of active matrix metalloproteinase type 1 (MMP-1) and tissue inhibitor of metalloproteinases type 1 (TIMP-1) levels. Vessels grown at a distension rate of 165 bpm had significantly higher collagen levels than those grown under static conditions. MMP-1 and TIMP-1 levels were also higher under pulsed conditions as compared with nonpulsed conditions. For the 90- and 165-bpm conditions, collagen and MMP-1 levels were not significantly different. TIMP-1 levels were significantly elevated at 165 bpm, indicating an increased cellular response to mechanical stimulation. Mechanical forces and their transduction represent a means to enhance the physical properties of artificial blood vessels, possibly by affecting the rate of extracellular matrix deposition and remodeling.

ECM gene expression correlates with in vitro tissue growth and development in fibrin gel remodeled by neonatal smooth muscle cells

A tissue growth and development process occurred in neonatal SMC-fibrin gel constructs when cultured in DMEM supplemented with TGF-beta1 and insulin over a 5 week period. These constructs may thus serve as the basis for cardiovascular tissue replacements and future models of cardiovascular tissue growth, repair and regeneration. Following fibrin gel contraction during week 1, peak rates of SMC proliferation, collagen production and tropoelastin production occurred between weeks 1-4. Organized, cross-linked collagen and elastic fibers replaced the degrading fibrin over weeks 3-5 and were manifested as increased mechanical strength. The peak rate of SMC proliferation (weeks 1-2) preceded that for maximum collagen production (weeks 2-4), which was consistent with the 3 week time point of maximum expression of collagen type I and III from qRT-PCR. Insoluble elastin quantification revealed that the majority of elastic fibers were produced by week 4, which was also consistent with the qRT-PCR data showing a dramatic down-regulation of tropoelastin expression by week 4, indicating elastogenesis occurred during the early stages of tissue growth and development. There was a strong up-regulation of lysyl oxidase expression during weeks 1-3 with a peak in expression at week 3, correlating with the phases of collagen and tropoelastin production. An increase in MMP-2 expression over weeks 1-5 suggested an increase in ECM remodeling as the tissue developed. Mechanical strength doubled over weeks 4-5 when production of collagen and elastic fibers and expression of lysyl oxidase were subsiding. This may have been due in part to the more organized collagen fibrils evident from the histological sections in weeks 3-5.