Acetylated oligopeptide and N-acetylcysteine protect against iron overload-induced dentate gyrus hippocampal degeneration through upregulation of Nestin and Nrf2/HO-1 and downregulation of MMP-9/TIMP-1 and GFAP

Iron accumulation in the brain causes oxidative stress, blood-brain barrier (BBB) breakdown, and neurodegeneration. We examined the preventive effects of acetylated oligopeptides (AOP) from whey protein on iron-induced hippocampal damage compared to N-acetyl cysteine (NAC). This 5-week study used 40 male albino rats. At the start, all rats received 150 mg/kg/day of oral NAC for a week. The 40 animals were then randomly divided into four groups: Group I (control) received a normal diet; Group II (iron overload) received 60 mg/kg/day intraperitoneal iron dextran 5 days a week for 4 weeks; Group III (NAC group) received 150 mg/kg/day NAC and iron dextran; and Group IV (AOP group) received 150 mg/kg/day AOP and iron dextran. Enzyme-linked immunosorbent assay, spectrophotometry, and qRT-PCR were used to measure MMP-9, tissue inhibitor metalloproteinase-1 (TIMP-1), MDA, reduced glutathione (GSH) levels, and nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) gene expression. Histopathological and immunohistochemical detection of nestin, claudin, caspase, and GFAP was also done. MMP-9, TIMP-1, MDA, caspase, and GFAP rose in the iron overload group, while GSH, Nrf2, HO-1, nestin, and claudin decreased. The NAC and AOP administrations improved iron overload-induced biochemical and histological alterations. We found that AOP and NAC can protect the brain hippocampus from iron overload, improve BBB disruption, and provide neuroprotection with mostly no significant difference from healthy controls.

Kechuanning Gel Plaster Exerts Anti-inflammatory and Immunomodulatory Effects on Ovalbumin-induced Asthma Model Rats via ERK Pathway

BACKGROUND

We aimed to evaluate the therapeutic effects of Kechuanning gel plaster on ovalbumin (OVA)-induced rat model of asthma.

METHODS

Rats were injected with OVA to induce asthma, and Kechuanning gel plaster was administered after the OVA challenge. The immune cell counts in the bronchial alveolar lavage fluid (BALF) were calculated after Kechuanning gel plaster administration. The levels of immune factors in BALF and serum OVA-specific IgE levels were analyzed. Western blot analysis and immunohistochemistry were carried out to analyze the following proteins: C-FOS, C-JUN, RAS p21 protein activator 1 (RASA1), matrix metalloproteinase 9 (MMP9), RAF1, p-MEK1, tissue inhibitor of metalloproteinase-1 (TIMP1), and p-extracellular signal-regulated kinase 1 (ERK1).

RESULTS

Administration of Kechuanning gel plaster led to decreased immune cell counts, inflammatory cytokines (interleukin (IL)-1β, IL13, and IL17), and OVA-specific IgE expression. Compared to the normal group, the C-FOS, C-JUN, RASA1, MMP9, RAF1, MEK1, TIMP1, and p- ERK1 expressions in the model group were significantly increased, whereas Kechuanning gel plaster administration decreased C-JUN, MMP9, TIMP1, RAF1, MEK1, p-ERK1, C-FOS, and RASA1 protein levels.

CONCLUSION

Kechuanning gel plaster exerted its therapeutic effects on OVA-induced asthma model rats through the ERK signaling pathway. Kechuanning gel plaster could be considered as a potential alternative therapeutic agent for the management of asthma.

Hydroalcoholic extract of Scrophularia striata has a significant therapeutic effect on thioacetamide-induced liver cirrhosis in rats

OBJECTIVES

Liver cirrhosis is one of the most important causes of death from liver diseases. Nowadays, the use of herbal medicines has increased due to its availability, less side effects and cheapness for the treatment of liver diseases. The present study was conducted to examine therapeutic effects of hydroalcoholic extract of Scrophularia striata (S. striata) on thioacetamide-induced liver cirrhosis in rats through evaluate its effects on oxidative stress markers and the expression of metalloproteinase 1 (TIMP 1), toll-like receptor-4 (TLR-4), and Mitofusin (MFN2) genes.

METHODS

24 male rats were selected by simple random sampling. Rats were randomly assigned to four groups: group I: healthy rats, group II: thioacetamide (TAA) injected rats, group III: TAA injected rats+100 mg/kg bw of S. striata and group IV: TAA injected rats+200 mg/kg bw of S. striata. Liver cirrhosis was induced in rats by a 300 mg/kg bw TAA administration twice with an interval of 24 h. After 8 weeks of treatment by S. striata at doses of 100 and 200 mg/kg bw, biochemical factors and oxidative stress markers (SOD, TAC, GPX, CAT and MDA) were measured using spectrophotometric methods. Also, gene expression of TIMP 1, TLR-4, and MFN2 were analyzed using real-time PCR. ANOVA and Bonferroni post hoc test analysis were applied to evaluate the data.

RESULTS

The results showed the S. striata extract significantly improve the serum ALT, AST and ALP levels, TIMP 1, TLR-4, and MFN2 genes and oxidative stress markers (SOD, TAC, GPX, CAT and MDA) in the liver tissues when compared to control group (p<0.05). Also, it was found that the beneficial effects of the S. striata were dose-dependent.

CONCLUSIONS

Based on the results obtained S. striata by reducing the expression of TIMP 1, TLR-4, and MFN2 genes and improving oxidative stress might be used as adjuvant treatment for liver cirrhosis.

Pacenta polypeptide injection alleviates the fibrosis and inflammation in cigarette smoke extracts-induced BEAS-2B cells by modulating MMP-9/TIMP-1 signaling

Chronic obstructive pulmonary disease (COPD) has high morbidity and mortality. Here, we aimed to explore the roles and potential correlation of placenta polypeptide injection (PPI) and MMP-9/TIMP-1 signaling pathway in COPD. BEAS-2B cells were treated with cigarette smoke extract (CSE) to establish a COPD cell model in vitro. The cell survival and cytotoxic effect were measured by CCK-8, LDH release and flow cytometry assays. The inflammatory responses were determined by western blot and ELISA assay. Cell fibrosis was assessed by immunofluorescence and western blot assays. PPI treatment had no cytotoxic effect on BEAS-2B cells until the final concentration reached to 10%. In the range of 0%-8% final concentration, PPI treatment weakened CSE-induced the decrease of cell viability and the increase of LDH level in a concentration-dependent manner. Four percent PPI treatment enhanced cell viability and decreased cell apoptosis of CSE-treated cells in a time-dependent manner. Moreover, 4% PPI treatment significantly decreased inflammatory responses and fibrosis induced by CSE, while AMPA (MMPs agonist) had opposite effects. Notably, AMPA reversed the protective roles of PPI on CSE-induced inflammation and fibrosis. Mechanistically, 4% PPI treatment significantly suppressed MMP-1, MMP-2, MMP-3, MMP-9, MMP-13, and MMP-19 levels, but enhanced TIMP-1, TIMP-2, TIMP-3, and TIMP-4 levels. Among them, MMP-9 and TIMP-1 might be the main target of PPI. PPI effectively attenuated CSE-induced inflammation and fibrosis in vitro by regulating MMP-9/TIMP-1 signaling pathway.

Upregulated TIMP1 facilitates and coordinates myometrial contraction by decreasing collagens and cell adhesive capacity during human labor

Myometrial contraction is one of the key events involved in parturition. Increasing evidence suggests the importance of the extracellular matrix (ECM) in this process, in addition to the functional role of myometrial smooth muscle cells, and our previous study identified an upregulated tissue inhibitor of metalloproteinase 1 (TIMP1) in human laboring myometrium compared to nonlabor samples. This study aimed to further explore the potential role of TIMP1 in myometrial contraction. First, we confirmed increased myometrial TIMP1 levels in labor and during labor with cervical dilation using transcriptomic and proteomic analyses, followed by real-time PCR, western blotting, and immunohistochemistry. Then, a cell contraction assay was performed to verify the decreased contractility after TIMP1 knockdown in vitro. To further understand the underlying mechanism, we used RNA-sequencing analysis to reveal the upregulated genes after TIMP1 knockdown; these genes were enriched in collagen fibril organization, cell adhesion, and ECM organization. Subsequently, a human matrix metalloproteinase (MMP) array and collagen staining were performed to determine the TIMPs, MMPs and collagens in laboring and nonlabor myometrium. A real-time cell adhesion assay was used to detect cell adhesive capacity. The results showed upregulated MMP8 and MMP9, downregulated collagens, and attenuated cell adhesive capacity in laboring myometrium, while lower MMP levels and higher collagen levels and cell adhesive capacity were observed in nonlabor. Moreover, TIMP1 knockdown led to restoration of cell adhesive capacity. Together, these results indicate that upregulated TIMP1 during labor facilitates and coordinates myometrial contraction by decreasing collagen and cell adhesive capacity, which may provide effective strategies for the regulation of myometrial contraction.

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

OBJECTIVE

The blood-brain barrier (BBB) plays a critical role in central nervous system homeostasis, and the integrity of BBB 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.

METHODS

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.

RESULTS

Our results indicated that MMP-3 and MMP-9 caused a dose-dependent disruption of the BBB, with 1.5 µM 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.

CONCLUSION

MMP-9 and MMP-3 disrupt the BBB by degrading tight junctions in endothelial cells, and TIMP-1 could inhibit the disruptive effect of MMP-3 and MMP-9 by showing potential as therapeutic protein against MMP-related diseases where BBB disruption plays a role.

Regorafenib prevents the development of emphysema in a murine elastase model

Emphysema is a chronic obstructive lung disease characterized by inflammation and enlargement of the air spaces. Regorafenib, a potential senomorphic drug, exhibited a therapeutic effect in porcine pancreatic elastase (PPE)-induced emphysema in mice. In the current study we examined the preventive role of regorafenib in development of emphysema. Lung function tests and morphometry showed that oral administration of regorafenib (5 mg/kg/day) for seven days after instillation of PPE resulted in attenuation of emphysema. Mechanistically, regorafenib reduced the recruitment of inflammatory cells, particularly macrophages and neutrophils, in bronchoalveolar lavage fluid. In agreement with these findings, measurements using a cytokine array and ELISA showed that expression of inflammatory mediators including interleukin (IL)-1β, IL-6, and CXCL1/KC, and tissue inhibitor of matrix metalloprotease-1 (TIMP-1), was downregulated. The results of immunohistochemical analysis confirmed that expression of IL-6, CXCL1/KC, and TIMP-1 was reduced in the lung parenchyma. Collectively, the results support the preventive role of regorafenib in development of emphysema in mice and provide mechanistic insights into prevention strategies. [BMB Reports 2023; 56(8): 439-444].

Pioglitazone inhibits oxidative stress, MMP-mediated inflammation and vascular dysfunction in high glucose-induced human saphenous vein grafts

AIMS

The aim of this study was to investigate the effects of pioglitazone on reactive oxygen species (ROS), expressions/activities of MMPs and TIMP-2, and VSMC proliferation and vascular reactivity in high glucose (HG)-induced human saphenous vein (HSV) grafts.

METHODS

HSV grafts (n = 10) obtained from patients undergoing CABG were incubated with 30 mM glucose and/or 10 μM pioglitazone or 0.1 % DMSO for 24 h after endothelium removal. ROS levels were examined by chemiluminescence assay, MMP-2,-9,-14, TIMP-2, and α-SMA expression/activity was determined by gelatine zymography/immunohistochemistry. Vascular reactivity to potassium chloride, noradrenaline, serotonin, prostaglandin F_2α and papaverine was assessed in HSVs.

RESULTS

HG induced superoxide anion (SA) (123 %) and other ROS levels (159 %), up-regulated MMP-2 expression (180 %)/activity (79 %), MMP-14 expression (24 %) and MMP-9 activity while down-regulating TIMP-2 expression (27 %). HG elevated total MMP-2/TIMP-2 ratio (483 %) and MMP-14/TIMP-2 ratio (78 %). However, HG plus pioglitazone inhibited SA (30 %) and other ROS levels (29 %), down-regulated MMP-2 expression (76 %)/activity (83 %), MMP-14 expression (38 %) and MMP-9 activity, while reversing TIMP-2 expression (44 %). HG plus pioglitazone decreased total MMP-2/TIMP-2 ratio (91 %) and MMP-14/TIMP-2 ratio (59 %). HG impaired contractions to all agents but pioglitazone improved them.

CONCLUSIONS

Pioglitazone may contribute to the prevention of restenosis and maintaining vascular function in HSV grafts of DM patients undergoing CABG.

Effect of Irisin on Human Nucleus Pulposus Cells: New Insights into the Biological Cross-talk Between Muscle and Intervertebral Disk

STUDY DESIGN

In vitro study.

OBJECTIVE

To investigate the effect of irisin on human nucleus pulposus cells (hNPCs) in vitro.

SUMMARY OF BACKGROUND DATA

Physical exercise (PE) favours weight loss and ameliorates function in patients with low back pain. Although there is no biological evidence that the intervertebral disk (IVD) can respond to PE, recent studies have shown that running is associated with increased IVD hydration and hypertrophy. Irisin, a myokine released upon muscle contraction, has demonstrated anabolic effects on different cell types, including chondrocytes.

MATERIALS AND METHODS

hNPCs were exposed to 5, 10, and 25 ng/mL irisin. Cell proliferation, glycosaminoglycan (GAG) content, metabolic activity, gene expression of collagen type II (COL2), matrix metalloproteinase (MMP)-13, tissue inhibitor of matrix metalloproteinase (TIMP)-1 and TIMP-3, aggrecan (ACAN), interleukin (IL)-1β, a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-5 were assessed. In addition, MTT assay and ADAMTS-5, COL2, TIMP-1, and IL-1β gene expression were evaluated following incubation with irisin for 24 hours and subsequent culture with 10 ng/mL IL-1β and vice versa (incubation for 24 hours with IL-1β and subsequent culture with irisin).

RESULTS

Irisin increased hNPC proliferation, metabolic activity, and GAG content, as well as COL2, ACAN, TIMP-1 and TIMP-3 gene expression, while decreasing MMP-13 and IL-1β mRNA levels. Irisin pretreatment of hNPCs cultured in proinflammatory conditions resulted in a rescue of metabolic activity and a decrease of IL-1β levels. Similarly, incubation of hNPCs with IL-1β and subsequent exposure to irisin led to an increment of metabolic activity, COL2 gene expression, and a reduction of IL-1β and ADAMTS-5 levels.

CONCLUSIONS

Irisin increases hNPC proliferation, GAG content, metabolic activity, and promotes anabolic gene expression while reducing catabolic markers. Irisin may be one of the mediators by which PE and muscle tissues modulate IVD metabolism, suggesting the existence of a biological cross-talk between the muscle and IVD.

[Lutein inhibits the adhesion, invasiveness and metastasis of human prostate cancer PC-3M cells]

OBJECTIVE

To explore the effects of lutein on the adhesion, invasiveness and metastasis of human prostate cancer PC-3M cells and its action mechanism.

METHODS

We divided human prostate cancer PC-3M cells into a control, a low-dose lutein, a medium-dose lutein and a high-dose lutein group, and treated them with 0, 10, 20 and 40 μmol/L lutein, respectively. Then we examined the adhesion of the cells to matrix by cell adhesion assay and the changes in cell pseudopodia by Phalloidin staining, detected the expressions of paxillin, matrix metalloproteinase 2 (MMP-2), MMP-9, recombinant tissue inhibitors of metalloproteinase 1 (TIMP-1), E-cadherin, N-cadherin and vimentin by Western blot, determined the invasiveness and migration of the cells by scratch and Transwell assays, and observed their dynamic movement by high-intension imaging.

RESULTS

Compared with the control, the lutein intervention groups showed significant reduction in the number of the cells adhered to matrix, the number of cell pseudopodia, the expressions of paxillin, MMP-2, MMP-9, N-cadherin and vimentin, the rates of migration, invasion and metastasis, and the distances of displacement and movement of the cells. However, the expressions of TIMP-1 and epithelial-mesenchymal transition-related E-cadherin were upregulated significantly.

CONCLUSION

Lutein can inhibit cell adhesion, reduce the expressions of MMPs, and suppress cell invasion and migration by inhibiting the process of epithelial-mesenchymal transition.

Overexpression of estrogen receptor β inhibits cellular functions of human hepatic stellate cells and promotes the anti-fibrosis effect of calycosin via inhibiting STAT3 phosphorylation

BACKGROUND

Estrogen receptor β (ERβ) is the major ER subtype in hepatic stellate cells (HSCs). Previously we reported phytoestrogen calycosin suppressed liver fibrosis progression and inhibited HSC-T6 cell functions, suggesting the effects may be related to ERβ. Here, we explore the effect of overexpressed ERβ on human HSCs and the role of ERβ in pharmacological action of calycosin.

METHODS

LX-2 cells were transfected with lentivirus to overexpress ERβ. In the presence or absence of overexpressed ERβ, the effects of ERβ and calycosin on proliferation, migration, activation, collagen production and degradation of TGF-β1-induced LX-2 cells and the role of ERβ in the inhibition effect of calycosin were investigated. LX-2 cells overexpressed with ERβ or treated with ER non-selective antagonist ICI182,780 were used to investigate the regulation of ERβ on JAK2/STAT3 signaling pathway. CCK-8 method was used to screen effective doses of calycosin and investigate cell proliferation. The cell migration was detected by transwell chamber assay. The expression of α-SMA was detected by immunofluorescence and western blot. The protein expressions of Col-I, MMP1, TIMP1, JAK2, p-JAK2, STAT3 and p-STAT3 were detected by western blot.

RESULTS

ERβ overexpressed lentivirus was successfully transfected into LX-2 cells with high efficiency. Overexpressed ERβ or calycosin alone inhibited the TGF-β1-induced LX-2 cell proliferation and migration, downregulated the protein expressions of α-SMA, Col-I, TIMP-1, p-STAT3 and upregulated MMP-1. Both overexpressed ERβ and calycosin had no significant effect on JAK2, p-JAK2 and STAT3 expressions. ERβ overexpression further enhanced the above effects of calycosin. However, after the cells were treated with ICI182,780, downregulation of STAT3 phosphorylation induced by calycosin was reversed.

CONCLUSIONS

ERβ mediated the inhibition of major functions of LX-2 cell possibly by inhibiting the phosphorylation of STAT3, and was an important pathway through which calycosin exerted anti-liver fibrosis effect.

[Eucommia ulmoides Oliv polysaccharide reduces the injury of IL-1β-induced chondrocyte by inhibiting NF-κB pathway]

OBJECTIVE

To investigate the effects of Eucommia ulmoides Oliv polysaccharide on the injury of interleukin-1β(IL-1β)-induced chondrocyte and its possible mechanism.

METHODS

ATDC5 was treated with 10 μg/ml IL-1β to establish osteoarthritis chondrocyte inflammation model, mouse chondrocyte ATDC5 were cultured in vitro and randomly divided into blank group, model group, model+Eucommia ulmoides Oliv polysaccharide low concentration group, model+Eucommia ulmoides Oliv polysaccharide medium concentration group and model+Eucommia ulmoides Oliv polysaccharide high concentration group. The cells in the blank group were cultured with conventional medium;the cells in the model group cells were cultured with a medium containing 10 ?g/ml IL-1β, and the cells in the model+Eucommia ulmoides Oliv polysaccharide low concentration group, model+Eucommia ulmoides Oliv polysaccharide medium concentration group and model+Eucommia ulmoides Oliv polysaccharide high concentration group were co-cultured with medium containing 100, 200, 400 μg/ml Eucommia ulmoides Oliv polysaccharide and 10 μg/ml IL-1β. After the cells of each group were cultured for 24 h, 48 h and 72 h, CCK-8 method was used to detect cell viability. After the cells of each group were cultured for 48 h, flow cytometry and DAPI staining were used to detect cell apoptosis;ELISA method was used to detect the expression of TNF-α, NO, IFN-γ and IL-6 in cells; DCFH-DA method was used to detect the content of ROS in cells;Western blot was used to detect the protein expression of TIMP-1, MMP-13 and NF-κB signaling pathway-related P65 and p-P65;Immunofluorescence staining was used to observe the localization of NF-κB P65 cells.

RESULTS

Compared with the blank group, the ATDC5 cell viability and the protein expression of TIMP-1 in the model group reduced (P<0.05), while apoptosis rate, the levels of TNF-α, NO, IFN-γ and IL-6, the content of ROS, the protein expression of MMP-13 and p-P65, and the number of P65+ in the nucleus increased(P<0.05). Compared with the model group, the ATDC5 cell viability and the protein expression of TIMP-1 in the model+Eucommia ulmoides Oliv polysaccharide low concentration group, model+Eucommia ulmoides Oliv polysaccharide medium concentration group and model+Eucommia ulmoides Oliv polysaccharide high concentration group increased (P<0.05), while apoptosis rate, the levels of TNF-α, NO, IFN-γ and IL-6, the content of ROS, the protein expression of MMP-13 and p-P65, and the number of P65+ in the nucleus reduced (P<0.05).

CONCLUSION

The results showed that Eucommia ulmoides Oliv polysaccharide could promote proliferation of IL-1β-induced chondrocyte ATDC5 and inhibit its apoptosis, inflammatory response and matrix degradation. Its mechanism may be related to the inhibition of the activation of NF-κB pathway.

[Effect of Taohong Siwu Decoction() early intervention on mesenchymal stem cells homing in fracture healing in rats]

OBJECTIVE

To observe the effects of Taohong Siwu Decoction(, THSWD) on the mesenchymal stem cells(MSCs) migration, homing number and cytokine expression in callus during the early process of fracture healing, and to explore the mechanism of THSWD on accelerationg fracture healing by regulating the homing of MSCs in rats.

METHODS

A rat model of right femoral shaft open fracture was established. Thirty-two 5-week-old male Sprague-Dawley rats, weighting 110 to 130 g, were divided into control group, low-dose group, medium-dose group and high-dose group by using random number table. Distilled water was given to the control group, and the other groups were given Taohong Siwu Decoction. The rats were gavaged twice a day for 5 consecutive days after surgery. Bone volume/tissue volume(BV/TV) and bone mineral density(BMD) were observed using micro-computed tomography (micro-CT) at 21 days after surgery. At 5 days post-fracture, peripheral blood MSCs from THSWD treated and untreated rats were cultured in vitro. Subsequently, the migration ability of MSCs was observed by cell migration assay. The number of MSCs homing to the callus at the early stage of fracture (5 d) was detected by Immunohistochemistry (IHC). Protein chip was used to detect the expression of cytokines in callus.

RESULTS

Micro-CT results showed that BV/TV was higher in the high-dose group than in the medium-dose group (P=0.032), and higher in the medium-dose group than in the low-dose group(P=0.041), with no difference between the control and low-dose group (P=0.651). In addition, there was no difference in BMD between low-dose group and the model group (P=0.671), and lower in the low-dose group than in the medium-dose group(P=0.018), and the medium-dose group was lower than the high-dose group(P=0.008). Cell migration assay showed that THSWD promotes enhanced the migration ability of peripheral blood MSCs. IHC assay revealed that CD45^-, CD90⁺, CD29⁺ MSCs significantly increased in bone callus after THSWD intervention compared with the control group. Protein chip showed that THSWD promoted the upregulation of CINC-1(×2.91), CINC-3(×1.59), LIX(×1.5), Thymus Chemokine (×2.55), VEGF (×1.22) and the down-regulation of TIMP-1 (×2.98).

CONCLUSION

THSWD, a representative formula of "promoting blood circulation and removing blood stasis", can significantly accelerate fracture healing, and its mechanism may be related to enhancing the migration ability of peripheral blood MSCs and up-regulating CINC-1, CINC-3, LIX, Thymus Chemokine, VEGF and down-regulating TIMP-1 in bone callus, which promotes the peripheral blood MSCs homing in the early stage of fracture.

Tissue inhibitor of metalloproteinases 1 enhances rod survival in the rd1 mouse retina

Retinitis pigmentosa (RP), an inherited retinal degenerative disease, is characterized by a progressive loss of rod photoreceptors followed by loss of cone photoreceptors. Previously, when tissue inhibitor of metalloproteinase 1 (TIMP1), a key extracellular matrix (ECM) regulator that binds to and inhibits activation of Matrix metallopeptidase 9 (MMP9) was intravitreal injected into eyes of a transgenic rhodopsin rat model of RP, S334ter-line3, we discovered cone outer segments are partially protected. In parallel, we reported that a specific MMP9 and MMP2 inhibitor, SB-3CT, interferes with mechanisms leading to rod photoreceptor cell death in an MMP9 dependent manner. Here, we extend our initial rat studies to examine the potential of TIMP1 as a treatment in retinal degeneration by investigating neuroprotective effects in a classic mouse retinal degeneration model, rdPde6b-/- (rd1). The results clearly demonstrate that intravitreal injections of TIMP1 produce extended protection to delay rod photoreceptor cell death. The mean total number of rods in whole-mount retinas was significantly greater in TIMP-treated rd1 retinas (postnatal (P) 30, P35 (P<0.0001) and P45 (P<0.05) than in saline-treated rd1 retinas. In contrast, SB-3CT did not delay rod cell death, leading us to further investigate alternative pathways that do not involve MMPs. In addition to inducing phosphorylated ERK1/2, TIMP1 significantly reduces BAX activity and delays attenuation of the outer nuclear layer (ONL). Physiological responses using scotopic electroretinograms (ERG) reveal b-wave amplitudes from TIMP1-treated retinas are significantly greater than from saline-treated rd1 retinas (P<0.05). In later degenerative stages of rd1 retinas, photopic b-wave amplitudes from TIMP1-treated rd1 retinas are significantly larger than from saline-treated rd1 retinas (P<0.05). Our findings demonstrate that TIMP1 delays photoreceptor cell death. Furthermore, this study provides new insights into how TIMP1 works in the mouse animal model of RP.

[MORPHOLOGICAL CHARACTERISTICS OF OSSEOINTEGRATION AFTERAPPLICATION OF TITANIUM IMPLANTS WITH BIOACTIVE COATING AND RECOMBINANT BONE MORPHOGENETIC PROTEIN]

Experiments were carried out on 22 albino male Wistar rats to study the morphological peculiarities of osseointegration of titanium grafts with bioactive surface stimulated additionally with bone plastic material "Gamalant-paste-FORTE Plus" containing recombinant human bone morphogenetic protein-2 (rhBMP-2). In 9 rats the implants were placed into femoral bones after local treatment of bone canal with rhBMP-2-containing material. Another 9 animals were implanted but received no treatment, 4 rats formed the group of intact control. Zone of osseointegration was studied 4, 8 and 12 weeks after graft placement using histological and morphometric methods as well as immune histochemistry to demonstrate osteonectin, CD68, MMP-9, and TIMP-1. The study showed that preliminary treatment of bone canal with rhBMP-2-containing material preceding implant placement was accompanied by an additional osteoinductive effect. More intense and outrunning bone formation in the area of osseointegration was observed, together with remodeling and compaction of the contiguous cancellous bone, thus providing the necessary balance between MMP-9 and TIMP-1 with a high level of each factor expression.

Tissue inhibitor of metalloproteinases-1 protects human neurons from staurosporine and HIV-1-induced apoptosis: mechanisms and relevance to HIV-1-associated dementia

HIV-1-associated dementia (HAD)-relevant proinflammatory cytokines robustly induce astrocyte tissue inhibitor of metalloproteinases-1 (TIMP-1). As TIMP-1 displays pleotropic functions, we hypothesized that TIMP-1 expression may serve as a neuroprotective response of astrocytes. Previously, we reported that chronically activated astrocytes fail to maintain elevated TIMP-1 expression, and TIMP-1 levels are lower in the brain of HAD patients; a phenomenon that may contribute to central nervous system pathogenesis. Further, the role of TIMP-1 as a neurotrophic factor is incompletely understood. In this study, we report that staurosporine (STS) and HIV-1(ADA) virus, both led to induction of apoptosis in cultured primary human neurons. Interestingly, cotreatment with TIMP-1 protects neurons from apoptosis and reverses neuronal morphological changes induced by these toxins. Further, the anti-apoptotic effect was not observed with TIMP-2 or -3, but was retained in a mutant of the N-terminal TIMP-1 protein with threonine-2 mutated to glycine (T2G) that is deficient in matrix metalloproteinase (MMP)-1, -2 and -3 inhibitory activity. Therefore, the mechanism is specific to TIMP-1 and partially independent of MMP-inhibition. Additionally, TIMP-1 modulates the Bcl-2 family of proteins and inhibits opening of mitochondrial permeability transition pores induced by HIV-1 or STS. Together, these findings describe a novel function, mechanism and direct role of TIMP-1 in neuroprotection, suggesting its therapeutic potential in HAD and possibly in other neurodegenerative diseases.

An evolutionary recent neuroepithelial cell adhesion function of huntingtin implicates ADAM10-Ncadherin

The Huntington's disease gene product, huntingtin, is indispensable for neural tube formation, but its role is obscure. We studied neurulation in htt-null embryonic stem cells and htt-morpholino zebrafish embryos and found a previously unknown, evolutionarily recent function for this ancient protein. We found that htt was essential for homotypic interactions between neuroepithelial cells; it permitted neurulation and rosette formation by regulating metalloprotease ADAM10 activity and Ncadherin cleavage. This function was embedded in the N terminus of htt and was phenocopied by treatment of htt knockdown zebrafish with an ADAM10 inhibitor. Notably, in htt-null cells, reversion of the rosetteless phenotype occurred only with expression of evolutionarily recent htt heterologues from deuterostome organisms. Conversely, all of the heterologues that we tested, including htt from Drosophila melanogaster and Dictyostelium discoideum, exhibited anti-apoptotic activity. Thus, anti-apoptosis may have been one of htt’s ancestral function(s), but, in deuterostomes, htt evolved to acquire a unique regulatory activity for controlling neural adhesion via ADAM10-Ncadherin, with implications for brain evolution and development.

Recombinant GPI-anchored TIMP-1 stimulates growth and migration of peritoneal mesothelial cells

BACKGROUND

Mesothelial cells are critical in the pathogenesis of post-surgical intraabdominal adhesions as well as in the deterioration of the peritoneal membrane associated with long-term peritoneal dialysis. Mesothelial denudation is a pathophysiolocigally important finding in these processes. Matrix metalloproteinase (MMP) biology underlies aspects of mesothelial homeostasis as well as wound repair. The endogenous tissue inhibitors of metalloproteinases (TIMPs) moderate MMP activity.

METHODS AND FINDING

By modifying human TIMP-1 through the addition of a glycosylphosphatidylinositol (GPI) anchor, a recombinant protein was generated that efficiently focuses TIMP-1 on the cell surface. Treatment of primary mesothelial cells with TIMP-1-GPI facilitates their mobilization and migration leading to a dramatic increase in the rate of wound experimental closure. Mesothelial cells treated with TIMP-1-GPI showed a dose dependent increase in cell proliferation, reduced secretion of MMP-2, MMP-9, TNF-α and urokinase-type plasminogen activator (uPA), but increased tissue plasminogen activator (t-PA). Treatment resulted in reduced expression and processing of latent TGF-β1.

CONCLUSIONS

TIMP-1-GPI stimulated rapid and efficient in vitro wound closure. The agent enhanced mesothelial cell proliferation and migration and was bioactive in the nanogram range. The application of TIMP-1-GPI may represent a new approach for limiting or repairing damaged mesothelium.

Tissue inhibitor of matrix metalloproteinase 1 (TIMP1) controls adipogenesis in obesity in mice and in humans

AIMS/HYPOTHESIS

Extracellular matrix reorganisation is a crucial step of adipocyte differentiation and is controlled by the matrix metalloproteinase-tissue inhibitor of matrix metalloproteinase (TIMP) enzyme system. We therefore sought to define the role of TIMP1 in adipogenesis and to elucidate whether upregulation of TIMP1 in obesity has direct effects on adipocyte formation.

METHODS

TIMP1 protein levels and mRNA were measured in lean and obese mice with a focus on levels in adipose tissue. We also analysed the effect of recombinant murine TIMP1 on adipogenesis, adipocyte size and metabolic control in vitro and in vivo.

RESULTS

TIMP1 levels were increased in the serum and adipose tissue of obese mouse models. Recombinant murine TIMP1 inhibited adipocyte differentiation in 3T3-L1 as well as in subcutaneous primary pre-adipocytes. Conversely, neutralising TIMP1 with a specific antibody enhanced adipocyte differentiation. In vivo, injection of recombinant TIMP1 in mice challenged with a high-fat diet led to enlarged adipocytes. TIMP1-treated mice developed an impaired metabolic profile with increased circulating NEFA levels, hepatic triacylglycerol accumulation and accelerated insulin resistance. Altered glucose clearance in TIMP1-injected mice was due to changes in adipose tissue glucose uptake, whereas muscle glucose clearance remained unaffected.

CONCLUSIONS/INTERPRETATION

TIMP1 is a negative regulator of adipogenesis. In vivo, TIMP1 leads to enlarged adipocytes in the state of overnutrition. This might contribute to the detrimental metabolic consequences seen in TIMP1-injected mice, such as systemic fatty acid overload, hepatic lipid accumulation and insulin resistance.

Tissue inhibitor of metalloproteinase-1 counteracts glucolipotoxicity in the pancreatic β-cell line INS-1

BACKGROUND

Glucolipotoxicity might play an important role in the β cell decompensation stage during the development of obesity-associated type 2 diabetes. Tissue inhibitor of metalloproteinase-1 (TIMP-1) inhibits matrix metalloproteinase (MMP) activity and regulates proliferation and apoptosis of a variety of cell types, including pancreatic β-cells. In the present study, we investigated whether TIMP-1 counteracts glucolipotoxicity in the pancreatic β-cell line INS-1.

METHODS

INS-1 cells were incubated in normal or high glucose, with or without palmitate (0.4 mmol/L), in the presence of TIMP-1 or MMP inhibitor GM60001. In some experiments, cells were pretreated with phosphatidylinositol-3 (PI-3) kinase inhibitor, LY294002 or wortmannin. The amount of dead INS-1 cells was determined by HO342 and propidium iodide staining. Akt phosphorylation was evaluated by Western blotting analysis to investigate a possible mechanism of TIMP-1's action.

RESULTS

TIMP-1 protected INS-1 cells from glucolipotoxicity independent of MMP inhibition. TIMP-1 stimulated Akt phosphorylation. Inhibition of the PI-3 kinase pathway abolished the survival effect of TIMP-1.

CONCLUSION

TIMP-1 may counteract glucolipotoxicity induced β-cell death via a PI-3 kinase pathway.

A new role for TIMP-1 in modulating neurite outgrowth and morphology of cortical neurons

Background

Tissue inhibitor of metalloproteinases-1 (TIMP-1) displays pleiotropic activities, both dependent and independent of its inhibitory activity on matrix metalloproteinases (MMPs). In the central nervous system (CNS), TIMP-1 is strongly upregulated in reactive astrocytes and cortical neurons following excitotoxic/inflammatory stimuli, but no information exists on its effects on growth and morphology of cortical neurons.

Principal Findings

We found that 24 h incubation with recombinant TIMP-1 induced a 35% reduction in neurite length and significantly increased growth cones size and the number of F-actin rich microprocesses. TIMP-1 mediated reduction in neurite length affected both dendrites and axons after 48 h treatment. The effects on neurite length and morphology were not elicited by a mutated form of TIMP-1 inactive against MMP-1, -2 and -3, and still inhibitory for MMP-9, but were mimicked by a broad spectrum MMP inhibitor. MMP-9 was poorly expressed in developing cortical neurons, unlike MMP-2 which was present in growth cones and whose selective inhibition caused neurite length reductions similar to those induced by TIMP-1. Moreover, TIMP-1 mediated changes in cytoskeleton reorganisation were not accompanied by modifications in the expression levels of actin, βIII-tubulin, or microtubule assembly regulatory protein MAP2c. Transfection-mediated overexpression of TIMP-1 dramatically reduced neuritic arbour extension in the absence of detectable levels of released extracellular TIMP-1.

Conclusions

Altogether, TIMP-1 emerges as a modulator of neuronal outgrowth and morphology in a paracrine and autrocrine manner through the inhibition, at least in part, of MMP-2 and not MMP-9. These findings may help us understand the role of the MMP/TIMP system in post-lesion pre-scarring conditions.

[TIMP-1 secreted by fibroblasts inhibits tumor cell invasion and metastasis in mouse melanoma]

We constructed a recombinant adenoviral vector expressing human tissue inhibitors of metalloproteinase-1(TIMP-1), and evaluated the inhibition of TIMP-1 secreted by primary fibroblasts after infection with adenovirus-mediated TIMP-1 gene (Ad-TIMP-1) on tumor cell invasion and metastasis in mouse melanoma. It was found that TIMP-1 was detected in the supernatants of cultured mouse primary fibroblasts after infection with Ad-TIMP-1 by indirect enzyme-linked immunosorbent assay (ELISA). The TIMP-1 secreted by Ad-TIMP-1 infected primary fibroblast significantly inhibited B16BL6 cell invasion and metastasis both in vitro and in vivo. We also demonstrated that the primary fibroblasts transfected by Ad-TIMP-1, after being subcutaneously injected into mouse, can secreted TIMP-1 into the blood of mouse and maintained at the therapeutic in vivo levels of TIMP-1. These results suggest that the preparation of Ad-TIMP-1 infected primary fibroblast be an effective method to deliver TIMP-1 gene in vivo, which provides a new strategy of gene therapy and has the potential for clinical applications in the treatment of tumor cell metastasis.

Different effects of angiogenesis inhibitors IFN-alpha and TIMP-1 on lymphangiogenesis

This study was designed to examine the effects of angiogenesis inhibitors IFN-alpha and TIMP-1 on lymphangiogenesis. We cultured lymphatic endothelial (LE) cells from pig thoracic ducts and performed morphological observations using light microscopy, TEM, and confocal microscopy to confirm their lymphatic origin. We tested these cells for growth inhibition by angiogenesis inhibitors IFN-alpha and TIMP-1 using both the scraping line and MTT methods. In addition, we analyzed apoptosis using the Hoechst and Caspase staining methods. Finally, we tested IFN-alpha and TIMP-1 using in vivo inhibitory assays. By morphological observations, all LE cells in vivo and in vitro were found to be of very similar morphology. Both in vitro inhibitory assays of scraping line and MTT showed significant differences for the IFN-alpha treatment (p < 0.01) and no significant difference for TIMP-1. Hoechst and Caspase apoptosis assays demonstrated that IFN-alpha could induce apoptosis of LE cells, and TIMP-1 had little effect. IFN-alpha and TIMP-1 inhibitory in vivo assays showed a lack of healing following IFN-alpha treatment compared to control and TIMP-1 treatment. In summary, these different angiogenesis inhibitors have different effects on lymphangiogenesis. IFN-alpha inhibits proliferation and migration of LE cells in a dose-dependent fashion and induces apoptosis of LE cells while TIMP-1 has no significant inhibitory effects on proliferation, migration, or inducing apoptosis.

Tissue inhibitor of metalloproteinases-1 stimulates gene expression in MDA-MB-435 human breast cancer cells by means of its ability to inhibit metalloproteinases

Tissue inhibitor of metalloproteinases-1 (TIMP-1) is a widely expressed, secreted protein that functions primarily to inhibit members of a large family of metalloproteinases (MPs). Because of the ability of TIMP-1 to inhibit MPs, it functions in many of the same pathophysiological processes as these enzymes, e.g. wound healing, ovulation, angiogenesis, and cancer cell metastasis. TIMP-1 can also stimulate proliferation ([3H]thymidine incorporation) and cellular anabolic processes (Alamar Blue reduction). This stimulation has been shown to be dependent on the MP-inhibitory ability of TIMP-1 in the human breast cancer cell line MDA-MB-435 (Porter et al., Br J Cancer 90: 463, 2004). To shed light on the mechanism by which TIMP-1 stimulates cellular anabolic processes, an oligonucleotide microarray analysis was performed over a time course of TIMP-1 treatment of MDA-MB-435 cells. Fifteen genes whose mRNAs were differentially regulated were identified. Six (Importin-7, MGC10471, FOXC1, subunit p20 of Arp2/3 complex, mitochondrial ribosomal protein L32, and the serine/threonine kinase-4 (MST1)) of these genes were confirmed by quantitative real time PCR. These same mRNAs were shown to be regulated by the synthetic hydroxamate MP-inhibitor GM6001 but not by its inactive derivative GM6001*, suggesting that the differential regulation occurs through the MP-inhibitory ability of TIMP-1. These results suggest a complex action of TIMP-1 on cancer cells mediated by constitutively active cell surface metalloproteinases that release factors regulating cell signaling pathways; they may account for the paradoxical observation that elevated levels of TIMP-1 in tumors can correlate with an adverse prognosis.

Suppression effects of human recombinant tissue inhibitor of metalloproteinases-1(TIMP-1) on tumor proliferation using in vivo treatment model of well-differentiated colon cancer cell line, HT29

To investigate the suppressive effect of human recombinant TIMP-1 (rh-TIMP-1) on tumor proliferation using an in vivo xenograft system, HT29 was suspended in 0.1 ml phosphate buffered saline (PBS) and then subcutaneously injected in the back of female mice (BALB/C nu/nu). The mice were divided into 2 groups an and the tumor diameter was measured after rh-TIMP-1 (2 mg/kg) (rh-TIMP-1 group) or PBS (control group) was administered injections according to the following schedules. Schedule 1 : Beginning 2 weeks after the subcutaneous injection of HT29, an intraperitoneal injection of rh-TIMP-1 or PBS were performed twice a day (every 12 h) for 14 consecutive days. Schedule 2 : Beginning 1 week after the subcutaneous injection of HT29, an intraperitoneal injection was performed twice a day for 14 consecutive days. Schedule 3 : Intraperitoneal injections were started simultaneously with the subcutaneous injection of HT29, and then performed twice a day for 21 consecutive days. The mice were sacrificed and the tumors extirpated for immunohistochemical investigation. In addition, gelatin zymography and a cell proliferation assay were performed. With Schedule 1, the changes in the tumor diameter in the rh-TIMP-1 group followed the same course as those in the control group, and no suppressive effect on tumor proliferation was observed. However, with Schedule 3, a remarkable suppressive effect was observed throughout the treatment period. In immunostaining, more cases negative for MMP-9 were observed in the rh-TIMP-1 group than in the control group. Cases negative for CD34 were significantly more observed in the rh-TIMP-1 group than in the control group with Schedule 3. All of the results were obtained through the suppressive effect of rh-TIMP-1 on angiogenesis.

Functional modulation of Crohn's disease myofibroblasts by anti-tumor necrosis factor antibodies

BACKGROUND & AIMS

Infliximab induces immune cell apoptosis by outside-to-inside signaling through transmembrane tumor necrosis factor-alpha (mTNF). However, in inflamed gut, myofibroblasts also produce TNF-alpha, and the affects of anti-TNF antibodies on these structural cells are unknown. We investigated the action of infliximab on apoptosis, the production of matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMP)-1, and migration of Crohn's disease (CD) myofibroblasts.

METHODS

Colonic myofibroblasts were isolated from patients with active CD and controls. mTNF was evaluated by Western blotting and flow cytometry. Infliximab-treated myofibroblasts were analyzed for apoptosis by Annexin V staining and caspase-3. TIMP-1 and MMPs were measured by Western blotting, and fibroblast migration was assessed by using an in vitro wound-healing scratch assay.

RESULTS

CD myofibroblasts showed higher mTNF expression than control myofibroblasts. Infliximab had no effect on CD myofibroblast apoptosis, caspase-3 activation, and production of MMP-3 and MMP-12. However, infliximab induced a significant dose-dependent increase in TIMP-1 production, which was inhibited by the p38 mitogen-activated protein kinase inhibitor SB 203580. The anti-TNF agents adalimumab, etanercept, and p55 TNF-receptor-human IgG fusion protein also increased TIMP-1 production. The migration of CD myofibroblasts was enhanced significantly by infliximab and recombinant human TIMP-1, and infliximab-induced migration was inhibited by anti-TIMP-1 neutralizing antibody. Infliximab also decreased CD myofibroblast collagen production.

CONCLUSIONS

Our findings show a novel therapeutic pathway for anti-TNF therapies in enhancing TIMP-1 production and myofibroblast migration, which may reduce MMP activity and facilitate the wound healing.

Conjugated linoleic acid alters matrix metalloproteinases of metastatic mouse mammary tumor cells

Conjugated linoleic acid (CLA) is a group of linoleic acid derivatives that has been implicated in animal studies to reduce a number of components of mammary tumorigenesis. Previously, we showed that CLA could alter the latency and metastasis of the highly metastatic transplantable line 4526 mouse mammary tumor. Several possible mechanisms have been proposed for the actions of CLA, but here we assessed how CLA may act to alter the expression and activity of matrix-modifying proteins within tumors from line 4526. In vitro, highly metastatic mouse mammary tumor cells had significantly decreased invasiveness after treatment with CLA, an indication that matrix-modifying proteins may have been altered. Using these same highly metastatic cells, primary tumors were grown in mice of separate groups fed 0, 0.1, 0.5, and 1% CLA (wt:wt) and evaluated for their levels and activities of matrix-modifying enzymes, enzyme inhibitors, and enzyme activators. The addition of CLA to the diet increased steady-state levels of messenger RNA (mRNA) of the matrix metalloproteinases (MMP) -2 and -9 in primary tumors removed from mice. However, western analysis revealed that although relative levels of the proform of MMP-9 were consistent with the mRNA observations, MMP-2 proform levels were actually decreased by dietary CLA. The activity of MMP-2 was barely detectable, but gelatin zymography and an in vitro activity assay showed that MMP-9 activity was significantly decreased by CLA. The steady-state mRNA and protein levels of tissue inhibitors of metalloproteinase-1 (TIMP-1) and TIMP-2, natural inhibitors of MMP, were increased at higher dietary CLA levels relative to low or no CLA. Suppression of MMP activity, therefore, may be 1 pathway through which CLA reduces tumor invasion and spread.

Changes in the balance of the tissue inhibitor of matrix metalloproteinases (TIMPs)-1 and -3 may promote keratocyte apoptosis in keratoconus

Keratoconus is a disease in which the central cornea becomes thinned. This could result from corneal stromal cell apoptosis or be induced or perpetuated by the activation of matrix degrading enzymes, particularly members of the matrix metalloproteinase (MMP) family. In some circumstances, the MMP inhibitors TIMP-1 and TIMP-3 exhibit anti-apoptotic and pro-apoptotic properties, respectively. Because they potentially influence keratoconus progression, the effects of TIMP-1 and TIMP-3 on stromal cell viability were investigated. The TIMP-1 and TIMP-3 proteins were over-expressed in cultured corneal stromal cells by using the adenoviral vectors RAdTIMP-1 and RAdTIMP-3 and quantified by enzyme-linked immunosorbant assay (ELISA). Apoptotic cells were detected by TUNEL and caspase-3 activity. The anti-apoptotic effects of TIMP-1 were investigated by co-infecting it with RAdTIMP-1 and RAdTIMP-3 and by adding TIMP-1 protein to stromal cell cultures prior to infecting them with RAdTIMP-3. Immunohistochemistry was used to localise and determine relative numbers of apoptotic and TIMP producing stromal cells in sections of normal and keratoconic corneas. The results showed that over-expression of TIMP-3 induced apoptosis in corneal stromal cell cultures. Up-regulated TIMP-1 production or the addition of exogenous TIMP-1 protein prevented stromal cell overgrowth, changed stromal cell morphology and reduced the extent of TIMP-3 induced apoptosis. Localised relative concentrations of TIMP-1/TIMP-3 could thus determine whether these cells remain viable or become apoptotic. This may be relevant to the keratoconic condition since significantly more apoptotic cells were identified in the anterior stroma of keratoconic corneas than normal corneas and the majority of theTIMP-1 and TIMP-3 producing stromal cells were also located in this region.

MMP25 (MT6-MMP) is highly expressed in human colon cancer, promotes tumor growth, and exhibits unique biochemical properties

MMP25 (MT6-MMP) is one of the two glycosylphosphatidylinositol-anchored matrix metalloproteinases (MMPs) that have been suggested to play a role in pericellular proteolysis. However, its role in cancer is unknown, and its biochemical properties are not well established. Here we found a marked increase in MT6-MMP expression within in situ dysplasia and invasive cancer in 61 samples of human colon cancer. Expression of MT6-MMP in HCT-116 human colon cancer cells promoted tumori-genesis in nude mice. Histologically, the MT6-MMP-expressing tumors demonstrated an infiltrative leading edge in contrast to a rounded leading edge in vector control tumors. Biochemical and biosynthesis analyses revealed that MT6-MMP displayed on the cell surface exists as a major form of 120 kDa that likely represents enzyme homodimers linked by disulfide bonds. Upon reduction, a single 57-kDa active MT6-MMP was detected. Interestingly, neither membrane-anchored nor phosphatidylinositol-specific phospholipase C-released MT6-MMPs were found to be associated with tissue inhibitor of metalloproteinases (TIMPs) and did not activate pro-gelatinases (pro-MMP-2 and pro-MMP-9) even in the presence of exogenous TIMP-2 or TIMP-1. A catalytic domain of MT6-MMP was inhibited preferentially by TIMP-1 (K(i) = 0.2 nm) over TIMP-2 (K(i) = 2.0 nm), because of a slower association rate. These results show that MT6-MMP may play a role in colon cancer and exhibit unique biochemical and structural properties that may regulate proteolytic function at the cell surface.

Increase in matrix metalloproteinases from endothelial cells exposed to umbilical cord plasma from high birth weight newborns

Large for gestational age infants have increased risk of developing the metabolic syndrome and cardiovascular disease in child- and adulthood. The vascular endothelium is a target site in the pathogenesis of many cardiovascular disorders. The matrix metalloproteinases (MMP) are important modulators of the extracellular matrix and serve as markers of these disorders. Here, we asked whether umbilical cord plasma of high birth weight (HBW; >4 kg) infants could modulate functional properties of human umbilical vein endothelial cells (HUVEC) compared with plasma from normal birth weight (NBW; 3.1–3.6 kg) infants. To test this, HUVECs were exposed for 48 h to 20% venous cord plasma from HBW or NBW infants. The MMP activity in supernatants of HUVECs exposed to HBW plasma was nearly three times higher ( P < 0.05) than that obtained with NBW plasma. MMP-9, but not MMP-2, protein concentration and mRNA expression were enhanced in HBW ( P < 0.05). With specific blockers, MMP activity and mRNA-MMP-9 were inhibited by ∼60–70%. Cord lipid and insulin concentrations were similar ( P > 0.05) among the two groups. We could not detect any significant differences between the two groups in the concentrations of proinflammatory cytokines or specific tissue inhibitors of MMP in plasma or HUVEC supernatants. In conclusion, cord plasma from HBW infants induced more MMP-9 in HUVECs compared with cord plasma from NBW infants. Although not identified, cord plasma of HBW infants may contain factors that increase endothelial cell MMP. These findings may indicate an association between fetal nutritional conditions and endothelial cell functions.

Brain protection using autologous bone marrow cell, metalloproteinase inhibitors, and metabolic treatment in cerebral ischemia

Despite advances in imaging, understanding the underlying pathways, and clinical translation of animal models of disease there remains an urgent need for therapies that reduce brain damage after stroke and promote functional recovery in patients. Blocking oxidant radicals, reducing matrix metalloproteinase-induced neuronal damage, and use of stem cell therapy have been proposed and tested individually in prior studies. Here we provide a comprehensive integrative management approach to reducing damage and promoting recovery by combining biological therapies targeting these areas. In a rat model of transient cerebral ischemia (middle cerebral artery occlusion) gene delivery vectors were used to overexpress tissue inhibitor of matrix metalloproteinase 1 and 2 (TIMP1 and TIMP2) 3 days before ischemia. After occlusion, autologous bone marrow cells alone or in combination with agents to improve NO bioavailability were administered intraarterially. When infarct size, BrdU incorporation, and motor function recovery were determined in the treatment groups the largest beneficial effect was seen in rats receiving the triple combined therapy, surpassing effects of single or double therapies. Our study highlights the utility of combined drug, gene, and cell therapy in the treatment of stroke.

TIMP-1 regulates cell proliferation by interacting with the ninth zinc finger domain of PLZF

The tissue inhibitors of metalloproteinases (TIMPs) are multifunctional proteins that specifically inhibit matrix metalloproteinases (MMPs) and regulate extracellular matrix (ECM) turnover and tissue remodeling. This is directed by forming tightly bound inhibitory complexes with MMPs. Recent years have revealed important differences of various biological activities between TIMP families but molecular mechanisms are not clear. To define the molecular mechanisms of TIMP-1-dependent biological processes, we used TIMP-1 as bait in a yeast two-hybrid screen, along with a human ovary cDNA library. Further characterization revealed the ninth zinc finger domain as an interacting domain of the promyelocytic leukemia zinc finger protein (PLZF). Interaction of PLZF with TIMP-1 in mammalian cells was also confirmed by co-immunoprecipitation and with in vitro binding assays. We investigated whether TIMP-1-mediated anti-apoptotic activity could promote the growth of ovarian cancer in an experimental model system. TIMP-1 treatment was found to be more effective at increasing ovarian cancer growth when compared with PLZF in parallel experiments. Subsequently, the efficacy of a combined treatment with TIMP-1 and PLZF was investigated. In the presence of both of these proteins, TIMP-1 significantly reduced apoptosis induced by PLZF in cervical carcinoma cells. These combined results indicate that TIMP-1 functions as an anti-activator of the transcriptional repressive activity of PLZF.

Temporal relationship between MMP production and angiogenic process in HUVECs

Alterations in both cell-cell and cell-matrix interactions are associated with the activation of endothelial cells that initiate angiogenesis. Cell-matrix interactions are affected by changes in both cell surface receptors for matrix proteins and the composition of ECM. One of the molecular mechanisms involved in changes in these components is the action of neutral proteinases, particularly matrix metalloproteinases. To understand the involvement of MMPs in angiogenic processes, the in vitro model of human umbilical vein endothelial cells in culture was used. Zymography and ELISA showed that, as cell-cell contact and network-like structures were formed, there was down regulation of MMP-2 and MMP-9 associated with high levels of their endogenous inhibitors TIMP-1 and TIMP-2. On treatment with aspirin, which inhibited the cell-cell contact and network-like structure formation, there was no down regulation of MMPs and cells continued to produce MMP-2 and MMP-9. These results indicate a temporal relationship between MMP-2 and MMP-9 production by endothelial cells and the onset of angiogenic event.

Tissue inhibitor of metalloproteinase-2 inhibits T-cell infiltration and preserves pancreatic β-cell function in an in vitro type 1 diabetes mellitus model

Type 1 diabetes mellitus (T1DM) results from autoreactive T-cells that attack and destroy insulin producing pancreatic beta-cells. This knowledge has provided a framework for numerous efforts to prevent or mitigate T1DM at various stages of the disease. In this study, we utilized an organ culture model of type 1 diabetes to determine whether tissue inhibitors of metalloproteinases (TIMPs) could block T-cell migration into the pancreas and ultimately preserve beta-cell function. We measured T-cell repertoires, insulin secretion, and performed immunohistochemistry and confocal laser microscopy in order to evaluate the effect of TIMP-1, TIMP-2, and TIMP-3 on our in vitro T1DM organ culture model. TIMP-2 decreased T-cell transmigration and preserved insulin production in our T1DM organ culture model. Moreover, TIMP-2 inhibited transmigration of diabetogenic T-cells across an islet microvascular endothelial cell layer. Our findings suggest that TIMP-2 is effective at blocking infiltration of autoreactive T-cells into target pancreas tissue thereby preserving pancreatic beta-cell mass.

Effect of recombinant human tissue inhibitor of matrix metalloproteinase-1 in rabbit mandibular distraction osteogenesis: A histological and immunohistochemical study

BACKGROUND

Bone matrix metalloproteinases are capable of degrading bone matrix during the remodelling, and their degradation activities can be down regulated by the tissue inhibitors of matrix metalloproteinases. This study evaluated the influence of exogenous tissue inhibitor of matrix metalloproteinase-1 on the expression of matrix metalloproteinases and endogenous tissue inhibitor of matrix metalloproteinases in mandibular distraction osteogenesis.

MATERIAL AND METHODS

Fifteen New Zealand white rabbits were assigned to three groups: a negative control; a sham control group implanted with a collagen sheet; and an experimental group implanted with recombinant human tissue inhibitor of matrix metalloproteinase-1 impregnated in a collagen sheet. Rabbits were sacrificed at 6 weeks, 12 weeks and 24 weeks of consolidation.

RESULTS

Major expression of matrix metalloproteinases and tissue inhibitors of matrix metalloproteinases was observed at the early stage of consolidation, only positive signals of tissue inhibitors of matrix metalloproteinases were observed at 24 weeks. The addition of recombinant human tissue inhibitor of matrix metalloproteinases-1 did not affect bone maturation and remodelling.

CONCLUSIONS

An equilibrium of bone formation and resorption was reached at 24 weeks of consolidation in the rabbit mandible. No obvious influence of recombinant human tissue inhibitor of matrix metalloproteinase-1 on bone remodelling of mandibular distraction osteogenesis was noted.

UVA-mediated down-regulation of MMP-2 and MT1-MMP coincides with impaired angiogenic phenotype of human dermal endothelial cells

UVA irradiation, dose-dependently (5-20 J/cm2), was shown to impair the morphogenic differentiation of human microvascular endothelial cells (HMECs) on Matrigel. Parallely, UVA down-regulated the expression of MMP-2 and MT1-MMP, both at the protein and the mRNA levels. On the contrary, the production of MMP-1 and TIMP-1 by HMECs increased following UVA treatment. The inhibitory effect of UVA on MMP expression and pseudotubes formation was mediated by UVA-generated singlet oxygen (1O2). The contribution of MT1-MMP, but not TIMP-1, to the regulation of HMECs' angiogenic phenotype following UVA irradiation was suggested using elastin-derived peptides and TIMP-1 blocking antibody, respectively.

Tissue inhibitor of matrix metalloproteinase-1 suppresses apoptosis of mouse bone marrow stromal cell line MBA-1

We investigated the action of tissue inhibitor of metalloproteinase-1 (TIMP-1) on apoptosis and differentiation of mouse bone marrow stromal cell line MBA-1. TIMP-1 did not affect alkaline phosphatase (ALP) activity, suggesting that it is not involved in osteoblastic differentiation in MBA-1 cells. However, TIMP-1 inhibited MBA-1 apoptosis induced by serum deprivation in a dose-dependent manner. Our study also showed increased Bcl-2 protein expression and decreased Bax protein expression with TIMP-1 treatment. TIMP-1 decreased cytochrome c release and caspase-3 activation in MBA-1 cells. TIMP-1 activated phosphatidylinositol 3-kinase (PI3-kinase) and c-Jun N-terminal kinase (JNK), and the PI3-kinase inhibitor LY294002 or the JNK inhibitor SP600125 abolished its antiapoptotic activity. To investigate whether antiapoptotic action of TIMP-1 was mediated through its inhibition on MMP activities, we constructed mutant TIMP-1 by side-directed mutagenesis, which abolished the inhibitory activity of MMPs by deletion of Cys1 to Ala4. Wild-type TIMP-1 and mutant TIMP-1 expression plasmids were transfected in MBA-1 cells, and results showed that mutant TIMP-1 still protected the induced MBA-1 cell against apoptosis. These data suggest that TIMP-1 antiapoptotic actions are mediated via the PI3-kinase and JNK signaling pathways and independent of TIMP-1 inhibition of MMP activities.

GPI-anchored TIMP-1 treatment renders renal cell carcinoma sensitive to FAS-meditated killing

The resistance of tumours to immune-mediated lysis has been linked to the biology of matrix metalloproteinases (MMPs), and specifically to the cell surface expression of MMPs by the tumour cell. The endogenous tissue inhibitors of metalloproteinases (TIMPs) exhibit diverse physiological/biological functions including the moderation of tumour growth, metastasis and apoptosis. These biologic activities are mediated in part by the stoichiometry of TIMP/MMP/cell surface protein interactions. A glycosylphosphatidylinositol (GPI) anchor was fused to TIMP-1 to focus defined concentrations of this inhibitory protein on the surface of three renal cell carcinoma (RCC) cell lines (RCC-26, RCC-53 and A498) independently of cell surface protein-protein interactions. Exogenously added TIMP-1-GPI efficiently inserted into the RCC cell membrane and dramatically altered the association of MMPs with the cell surface. TIMP-1-GPI treatment inhibited RCC proliferation and rendered the normally FAS-resistant RCC cells sensitive to FAS-induced apoptosis but did not alter perforin-mediated lysis by cytotoxic effector cells. The increased sensitivity to FAS-mediated apoptosis correlated with an alteration in the balance of pro- and antiapoptotic BCL-2-family proteins. By interfering with the proliferative capacity and inducing sensitivity to immune effector mechanisms GPI-anchored TIMP-1 may represent a more effective version of the TIMP-1 protein for therapeutic strategies.

Matrix metalloproteinases are involved in mechanical stretch–induced activation of skeletal muscle satellite cells

When skeletal muscle is stretched or injured, myogenic satellite cells are activated to enter the cell cycle. This process depends on nitric oxide (NO) production, release of hepatocyte growth factor (HGF) from the extracellular matrix, and presentation of HGF to the c-met receptor. Experiments reported herein provide new evidence that matrix metalloproteinases (MMPs) are involved in the NO-dependent release of HGF in vitro. When rat satellite cells were treated with 10 ng/ml recombinant tissue inhibitor-1 of MMPs (TIMP-1) and subjected to treatments that induce activation in vitro, i.e., sodium nitroprusside (SNP) of an NO donor or mechanical cyclic stretch, the activation response was inhibited. In addition, conditioned medium generated by cultures treated with TIMP-1 plus SNP or mechanical stretch failed to activate cultured satellite cells and did not contain HGF. Moreover, NO(x) assay demonstrated that TIMP-1 does not impair NO synthase activity of stretched satellite cell cultures. Therefore, results from these experiments provide strong evidence that MMPs mediate HGF release from the matrix and that this step in the pathway is downstream from NO synthesis.

Beneficial and detrimental influences of tissue inhibitor of metalloproteinase-1 (TIMP-1) in tumor progression

Tissue inhibitor of metalloproteinase-1 (TIMP-1) is one representative of the natural matrix metalloproteinase (MMP) inhibitor family, encompassing four members. It inhibits all MMPs, except several MT-MMPs, and a disintegrin with a metalloproteinase domain (ADAM)-10 with Kis < nM. Unexpectedly, its upregulation was associated to poor clinical outcome for several cancer varieties. Such finding might be related to the growth-promoting and survival activities of TIMP-1 for normal and cancer cells. In most cases, such properties are MMP-independent and binding of TIMP-1 to an unknown receptor system can trigger JAK (or FAK)/PI3 kinase/Akt/bad-bclX2 (erythroid, myeloid, epithelial cell lines) or Ras/Raf1/FAK (osteosarcoma cell line) signaling pathways. The relationship between viral infection and TIMP-1 expression is here underlined. Thus, TIMP-1 might display a dual influence on tumor progression; either beneficial by inhibiting MMPs as MMP-9 and by impairing angiogenesis or detrimental by favoring cancer cells growth or survival. We consider that the proMMP-9/TIMP-1 balance is of critical importance in early events of tumor progression, and might show promise as diagnostic and prognostic marker of malignancy.

Exogenous tissue inhibitor of metalloproteinase-1 promotes endothelial cell survival through activation of the phosphatidylinositol 3-kinase/Akt pathway

Control of molecular targets and signaling pathways which improve endothelial cell survival may be an attractive concept for interfering with dysregulated vascular injury and remodeling, a key mechanism for transplant arteriosclerosis and chronic allograft rejection. In addition to inhibiting matrix metalloproteinase activity, it has been suggested by recent studies that the tissue inhibitor of metalloproteinase (TIMP)-1 may inhibit apoptosis in various cell types. The present work examines the possibility that TIMP-1 belongs to a protective pathway via antiapoptotic properties and investigates the signaling pathway mediated by TIMP-1 in human ECs. We demonstrate that exogenous, recombinant, TIMP-1 efficiently prevents apoptosis induced by TNFalpha in cycloheximide-sensitized ECs. The antiapoptotic effect of TIMP-1 was dose-dependent and a maximal effect of TIMP-1 (30% protection) was reached using 250 ng/mL of recombinant TIMP-1. We present evidence that TIMP-1 induces activation of PI3-kinase but not NFkappaB pathway in ECs. Our findings further indicate that TIMP-1-induced EC survival is mediated through activation of PI3-kinase pathway and the downstream phosphorylation of Akt kinase. Blocking the PI3-kinase pathway with wortmannin or LY294002 restores TNFalpha-mediated EC death. In conclusion, our findings suggest that TIMP-1, generated upon inflammation, acts as an antiapoptotic molecule that can prevent EC apoptosis through activation of the PI3-kinase and phosphorylation of the Akt kinase.

Increased soluble interleukin-1 receptor type II proteolysis in the endometrium of women with endometriosis

Numerous functional changes were observed in the intrauterine endometrial tissue of women with endometriosis. Our previous studies revealed a marked decrease in the expression of interleukin-1 receptor type 2 (IL-1RII), a decoy receptor known for its ability to buffer IL-1 effects. The aim of the present study was to assess whether post-translational mechanisms such as proteolysis may contribute to the down-regulation of IL-1RII levels. Our data showed that soluble IL-1RII (sIL-1RII) concentrations released by freshly cultured endometrial tissue were significantly lower in women with endometriosis than in normal women (P < 0.01) and further revealed a statistically significant correlation between increased proteolysis and decreased sIL-1RII levels (P < 0.05; r = -0.47). (125)I-labelled soluble recombinant human IL-1RII ([(125)I]srhIL-1RII) was significantly more degraded in culture supernatant of tissues from women with endometriosis compared to normal women (P < 0.05), and natural tissue inhibitor of matrix metalloproteinase (TIMP)-1 inhibited [(125)I]srhIL-1RII degradation. Incubation of srhIL-1RII with active rhMMP-9 resulted in a dose-dependent degradation of srhIL-1RII as analysed by western blotting. Dual immunofluorescence showed an increased immunostaining for matrix metalloproteinase-9 in situ in the endometrial tissue of women with endometriosis compared to normal women and a decreased immunostaining for IL-1RII. The present study showed a reduced release of sIL-1RII by the endometrial tissue of women with endometriosis and revealed a proteolytic post-translational mechanism which may be involved in the down-regulation of IL-1RII levels. This may enhance IL-1-mediated activation of endometrial cells and contribute to the local immuno-inflammatory process observed in endometriosis patients.

Effects of vaccinia virus anti-inflammatory protein 35K and TIMP-1 gene transfers on vein graft stenosis in rabbits

BACKGROUND

Vein graft stenosis is a common problem after bypass surgery. Vein grafts are ideal targets for gene therapy because transduction can be made ex vivo before grafting. Since chemokines and inflammatory factors are involved in vein graft thickening, we tested a hypothesis that the vaccinia virus anti-inflammatory protein 35K which can sequester CC-chemokines, can reduce vein graft thickening in vivo.

MATERIALS AND METHODS

We used adenovirus-mediated gene transfer (1x10(9) pfu/ml) of 35K and compared its effects on reducing stenosis in a rabbit jugular vein graft model with tissue inhibitor of metalloproteinase-1 (TIMP-1) and LacZ control gene. TIMP-1 was used in this study because it has previously been shown to inhibit vein graft stenosis in other model systems. The expression of transgenes in the transduced segments was confirmed by RT-PCR. Vein grafts were analyzed using immunohistological and morphometric methods at the three-day time-point and at two-week and four-week time-points.

RESULTS

It was found that the anti-inflammatory protein 35K was an efficient factor in reducing neointima formation at the two-week time-point, indicating that inflammatory factors play an important role in vein graft stenosis. At the four-week time-point, 35K still showed a reduced accumulation of macrophages. TIMP-1 also tended to reduce neointimal thickening at the two-week time-point as compared to LacZ.

CONCLUSION

It was found that 35K is an efficient factor in reducing neointima formation, macrophage accumulation and proliferation in rabbit vein grafts after adenoviral ex vivo gene transfer.

Tissue inhibitors of metalloproteinase 2 inhibits endothelial cell migration through increased expression of RECK

The antiangiogenic function of the tissue inhibitors of metalloproteinases (TIMPs) has been attributed to their matrix metalloproteinase inhibitory activity. Here we demonstrate that TIMP-1 but not Ala+TIMP-1 inhibits both basal and vascular endothelial growth factor (VEGF)-stimulated migration of human microvascular endothelial cells (hMVECs), suggesting that this effect is dependent on direct inhibition of matrix metalloproteinase (MMP) activity. In contrast, TIMP-2 and mutant Ala+TIMP-2, which is devoid of MMP inhibitory activity, block hMVEC migration in response to VEGF-A stimulation. TIMP-2 and Ala+TIMP-2 also suppress basal hMVEC migration via a time-dependent mechanism mediated by enhanced expression of RECK, a membrane-anchored MMP inhibitor, which, in turn, inhibits cell migration. TIMP-2 treatment of hMVECs increases the association of Crk with C3G, resulting in enhanced Rap1 activation. hMVECs stably expressing Rap1 have increased RECK expression and display reduced cell migration compared with those expressing inactive Rap1(38N). RECK-null murine embryo fibroblasts fail to demonstrate TIMP-2-mediated decrease in cell migration despite activation of Rap1. TIMP-2-induced RECK decreases cell-associated MMP activity. Anti-RECK antibody increases MMP activity and reverses the TIMP-2-mediated reduction in cell migration. The effects of TIMP-2 on RECK expression and cell migration were confirmed in A2058 melanoma cells. These results suggest that TIMP-2 can inhibit cell migration via several distinct mechanisms. First, TIMP-2 can inhibit cell migration after VEGF stimulation by direct inhibition of MMP activity induced in response to VEGF stimulation. Secondly, TIMP-2 can disrupt VEGF signaling required for initiation of hMVEC migration. Third, TIMP-2 can enhance expression of RECK via Rap1 signaling resulting in an indirect, time-dependent inhibition of endothelial cell migration.

Tissue inhibitor of metalloproteinase-1 protects human breast epithelial cells from extrinsic cell death: a potential oncogenic activity of tissue inhibitor of metalloproteinase-1

Tissue inhibitors of metalloproteinases (TIMPs) inhibit matrix metalloproteinases and some members of a disintegrin and metalloproteinase domain (ADAM) family. In addition, recent studies unveiled novel functions of TIMPs in the regulation of apoptosis. TIMP-1 inhibits intrinsic apoptosis by inducing TIMP-1 specific cell survival pathways involving focal adhesion kinase (FAK). TIMP-3, however, was shown to enhance extrinsic cell death by inhibiting the shedding of the cell surface death receptors mediated by tumor necrosis factor-alpha converting enzymes (TACE/ADAM-17). Here, we examined whether TIMP-1, an inhibitor of some of the ADAM family members, enhances the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced extrinsic apoptotic pathway. Surprisingly, we found that TIMP-1 effectively protects human breast epithelial cells from TRAIL-induced apoptosis, demonstrating opposite roles of TIMP-1 and TIMP-3 for the regulation of extrinsic apoptosis. TIMP-1 inhibition of TRAIL-induced apoptosis does not depend on its ability to inhibit matrix metalloproteinases or ADAM activities and is unrelated to its ability to stabilize active or decoy death receptors. Importantly, inhibition of PI 3-kinase signaling by wortmannin and down-regulation of FAK expression using siRNA significantly diminish TIMP-1 protection of human breast epithelial cells against TRAIL-induced extrinsic apoptosis. In addition, the in vitro three-dimensional culture studies showed that TIMP-1 inhibits lumen formation and apoptosis during morphogenesis of MCF10A acini. Taken together, these studies suggest that TIMP-1 may exert oncogenic activity in breast cancer through inhibition of both intrinsic and extrinsic apoptosis involving the FAK survival signal transduction pathway.

Exogenously added GPI-anchored tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) displays enhanced and novel biological activities

The family of tissue inhibitors of metalloproteinases (TIMPs) exhibits diverse physiological/biological functions including the inhibition of active matrix metalloproteinases, regulation of proMMP activation, cell growth, and the modulation of angiogenesis. TIMP-1 is a secreted protein that can be detected on the cell surface through its interaction with surface proteins. The diverse biological functions of TIMP-1 are thought to lie, in part, in the kinetics of TIMP-1/MMP/surface protein interactions. Proteins anchored by glycoinositol phospholipids (GPIs), when purified and added to cells in vitro, are incorporated into their surface membranes. A GPI anchor was fused to TIMP-1 to generate a reagent that could be added directly to cell membranes and thus focus defined concentrations of TIMP-1 protein on any cell surface independent of protein-protein interaction. Unlike native TIMP-1, exogenously added GPI-anchored TIMP-1 protein effectively blocked release of MMP-2 and MMP-9 from osteosarcoma cells. TIMP-1-GPI was a more effective modulator of migration and proliferation than TIMP-1. While control hTIMP-1 protein did not significantly affect migration of primary microvascular endothelial cells at the concentrations tested, the GPI-anchored TIMP-1 protein showed a pronounced suppression of endothelial cell migration in response to bFGF. In addition, TIMP-1-GPI was more effective at inducing microvascular endothelial proliferation. In contrast, fibroblast proliferation was suppressed by the agent. Reagents based on this method should assist in the dissection of the protease cascades and activities involved in TIMP biology. Membrane-fixed TIMP-1 may represent a more effective version of the protein for use in therapeutic expression.

Localization of tissue inhibitor of metalloproteinases 1 (TIMP-1) in human colorectal adenoma and adenocarcinoma

Tissue inhibitor of matrix metalloproteases 1 (TIMP-1) inhibits the proteolytic activity of matrix metalloproteases and hereby prevents cancer invasion. However, TIMP-1 also possesses other functions such as inhibition of apoptosis, induction of malignant transformation and stimulation of cell-growth. We have previously demonstrated that TIMP-1 is elevated in blood from colorectal cancer patients and that high TIMP-1 levels predict poor prognosis. To clarify the role of TIMP-1 in colorectal tumorigenesis, the expression pattern of TIMP-1 in benign and malignant colorectal tumors was studied. In all of 24 cases of colorectal adenocarcinoma TIMP-1 mRNA was detected by in situ hybridization. In all cases TIMP-1 expression was found in fibroblast-like cells located at the invasive front but was seen only sporadically in normal mucosa. No TIMP-1 mRNA was seen in any of the cases in benign or malignant epithelial cells, in vascular cells or smooth muscle cells. Comparison of sections processed for TIMP-1 in situ hybridization with sections immunohistochemically stained with antibodies against TIMP-1 showed good correlation between TIMP-1 mRNA and immunoreactivity. Combining TIMP-1 in situ hybridization with immunohistochemical staining for alpha-smooth muscle actin or CD68 showed TIMP-1 mRNA in myofibroblasts but not in macrophages. TIMP-1 mRNA was detected in 2 of 7 adenomatous polyps in the adenoma area: in both cases associated with focal stromal inflammation at the epithelial-stromal interface. In conclusion, TIMP-1 expression is a rare event in benign human colon tissue but is highly expressed by myofibroblasts in association with invading colon cancer cells.

TIMP-1 inhibits microvascular endothelial cell migration by MMP-dependent and MMP-independent mechanisms

It was reported over a decade ago that tissue inhibitor of metalloproteinases-1 (TIMP-1) suppresses angiogenesis in experimental models but the mechanism is still incompletely understood. This in vitro study focused on the molecular basis of TIMP-1-mediated inhibition of endothelial cell (EC) migration, a key step in the angiogenic process. Both recombinant human TIMP-1 and the synthetic MMP inhibitors, GM6001 and MMP-2-MMP-9 Inhibitor III, suppressed migration of human dermal microvascular endothelial cells (HDMVEC) in a dose-dependent fashion. The MMP-dependent inhibition of migration was associated with increased expression of the junctional adhesion proteins, VE-cadherin and PECAM-1, and VE-cadherin accumulation at cell-cell junctions. TIMP-1 also caused MMP-independent dephosphorylation of focal adhesion kinase (FAK) (pY397) and paxillin, which was associated with reduced number of F-actin stress fibers and focal adhesions. Moreover, TIMP-1 stimulated expression of PTEN that has been shown to reduce phosphorylation of FAK and inhibit cell migration. Our data suggest that TIMP-1 inhibits HDMVEC migration through MMP-dependent stimulation of VE-cadherin and MMP-independent stimulation of PTEN with subsequent dephosphorylation of FAK and cytoskeletal remodeling.

Increased lung matrix metalloproteinase-9 levels in extremely premature baboons with bronchopulmonary dysplasia

Matrix metalloproteinases (MMPs) regulate the formation of normal lung architecture. Extremely premature infants exposed to hyperoxia and mechanical ventilation often develop lung inflammation and injury. We hypothesized that an imbalance between MMPs and their tissue inhibitors plays a key role. Our hypothesis was tested to: 1) examine the ontogeny of lung MMPs and tissue inhibitors of metalloproteinases (TIMPs); and 2) determine the effects of hyperoxia and mechanical ventilation on lung MMPs and TIMPs in premature newborn baboons developing chronic lung disease/bronchopulmonary dysplasia (CLD/BPD). Lung specimens were obtained from five groups of gestational controls (GCs) sacrificed at 125, 140, 160, 175, and 185 (term) days of gestation, one fetal baboon model of CLD/BPD delivered at 125 days, and two at 140 days of gestation. Paraffin-embedded lung tissue sections were examined for pathological changes, and frozen lung specimens were analyzed for MMPs-1, -2, -8, and -9; TIMPs-1 and -2; and messenger RNA expression of type I collagen. In GCs, MMP-1 and -9 were elevated in the last trimester, whereas MMP-2 and -8 levels were decreased. Significant changes in lung architecture were noted in the BPD models. MMP-1 was increased in the 125-day model, but decreased in both 140-day models. MMP-8 and collagen mRNA levels were decreased, while MMP-9 and MMP-9 to TIMP-1 ratios were increased in all BPD models. We conclude that an imbalance between MMP-9 and TIMP-1 leading to excessive MMP-9 activity contributes to lung inflammation and edema in CLD/BPD.

MMP-9 regulates both positively and negatively collagen gel contraction: a nonproteolytic function of MMP-9

OBJECTIVE

Constrictive remodeling accounts for lumen loss in postangioplasty restenosis. Matrix metalloproteinase-9 (MMP-9) has been shown to prevent constrictive remodeling in vivo. To investigate potential mechanisms for this observation, we investigated the role of MMP-9 in smooth muscle cell (SMC)-mediated collagen gel contraction, an in vitro model of constrictive remodeling.

METHODS

Fischer rat SMCs were stably transfected with a construct-expressing rat-MMP-9 under the control of a tetracycline (Tet)-off promoter. SMCs were seeded in type I collagen gels (2.4 mg/ml) in the presence or not of tetracycline (1 microg/ml), and gel contraction was defined as the percentage of retraction of the collagen gel. The depletion of MMP-9 was obtained by using siRNA targeting MMP-9 mRNA or a blocking antibody.

RESULTS

Gel contraction was significantly reduced at all times when MMP-9 was overexpressed (Tet-) as compared with the control condition (Tet+). However, MMP-9 depletion of control (Tet+) SMCs (using siRNA or antibody) also inhibited gel contraction. To resolve the apparent discrepancy and determine if MMP-9 exerts a dose-dependent biphasic effect on gel contraction, conditioned medium and purified rat-MMP-9 were prepared. Gel contraction was significantly increased by addition of 0.8 ng/ml of MMP-9, while high concentrations of MMP-9 (> or =100 ng/ml) inhibited contraction. The addition of BB94 and TIMP-1 did not alter the inhibitory or stimulatory effect of MMP-9.

CONCLUSIONS

Our data suggest that MMP-9, independent of its proteolytic function, has a biphasic effect on SMC-mediated collagen gel contraction. Understanding the different roles of MMP-9 should allow the development of better therapeutic strategies for restenotic vascular disease.