Intracellular matrix metalloproteinase-2 (MMP-2) regulates human platelet activation via hydrolysis of talin

2014 ◽  
Vol 111 (01) ◽  
pp. 140-153 ◽  
Author(s):  
Christopher Mason ◽  
Stephen Lynch ◽  
James Benjamin ◽  
Dani Ashak ◽  
Jamunabai M. Prakash ◽  
...  

SummaryMatrix metalloproteinase (MMP) activity is generally associated with normal or pathological extracellular processes such as tissue remodeling in growth and development or in tumor metastasis and angiogenesis. Platelets contain at least three MMPs, 1, 2 and 9 that have been reported to stimulate or inhibit agonist-induced platelet aggregation via extracellular signals. The non-selective Zn+2 chelating MMP inhibitor, 1,10-phenanthroline, and the serine protease inhibitor, AEBSF, were found to inhibit all tested agonist-induced platelet aggregation reactions. In vitro analysis demonstrated that 1,10-phenanthroline completely inhibited MMP-1,2,and 9 but had little to no effect on calpain activity while the converse was true with AEBSF. We now demonstrate that MMP-2 functions intracellularly to regulate agonistinduced platelet aggregations via the hydrolytic activation of talin, the presumed final activating factor of glycoprotein (GP)IIb/IIIa integrin (the inside-out signal). Once activated GPIIb/IIIa binds the dimeric fibrinogen molecule required for platelet aggregation. The active intracellular MMP-2 molecule is complexed with JAK 2/STAT 3, as demonstrated by the fact that all three proteins are co-immunoprecipitated with either anti-JAK 2, or anti-STAT 3 antibodies and by immunofluorescence studies. The MMP-2 platelet activation pathway can be synergistically inhibited with the non-selective MMP inhibitor, 1,10-phenanthroline, plus a JAK 2 inhibitor. This activation pathway is distinct from the previously reported calpain-talin activating pathway. The identification of a new central pathway for platelet aggregation presents new potential targets for drug regulation and furthers our understanding of the complexity of platelet activation mechanisms.

2014 ◽  
Vol 111 (06) ◽  
pp. 1089-1101 ◽  
Author(s):  
Massimo Lenti ◽  
Emanuela Falcinelli ◽  
Marcella Pompili ◽  
Paola De Rango ◽  
Valentina Conti ◽  
...  

SummaryPurified active matrix metalloproteinase-2 (MMP-2) is able to promote platelet aggregation. We aimed to assess the role of MMP-2 expressed in atherosclerotic plaques in the platelet-activating potential of human carotid plaques and its correlation with ischaemic events. Carotid plaques from 81 patients undergoing endarterectomy were tested for pro-MMP-2 and TIMP-2 content by zymography and ELISA. Plaque extracts were incubated with gel-filtered platelets from healthy volunteers for 2 minutes before the addition of a subthreshold concentration of thrombin receptor activating peptide-6 (TRAP-6) and aggregation was assessed. Moreover, platelet deposition on plaque extracts immobilised on plastic coverslips under high shear-rate flow conditions was measured. Forty-three plaque extracts (53%) potentiated platelet aggregation (+233 ± 26.8%), an effect prevented by three different specific MMP-2 inhibitors (inhibitor II, TIMP-2, moAb anti-MMP-2). The pro-MMP-2/TIMP-2 ratio of plaques potentiating platelet aggregation was significantly higher than that of plaques not potentiating it (3.67 ± 1.21 vs 1.01 ± 0.43, p<0.05). Moreover, the platelet aggregation-potentiating effect, the active-MMP-2 content and the active MMP-2/pro-MMP-2 ratio of plaque extracts were significantly higher in plaques from patients who developed a subsequent major cardiovascular event. In conclusion, atherosclerotic plaques exert a prothrombotic effect by potentiating platelet activation due to their content of MMP-2; an elevated MMP-2 activity in plaques is associated with a higher rate of subsequent ischaemic cerebrovascular events.


1996 ◽  
Vol 76 (05) ◽  
pp. 774-779 ◽  
Author(s):  
John T Brandt ◽  
Carmen J Julius ◽  
Jeanne M Osborne ◽  
Clark L Anderson

SummaryImmune-mediated platelet activation is emerging as an important pathogenic mechanism of thrombosis. In vitro studies have suggested two distinct pathways for immune-mediated platelet activation; one involving clustering of platelet FcyRIIa, the other involving platelet-associated complement activation. HLA-related antibodies have been shown to cause platelet aggregation, but the mechanism has not been clarified. We evaluated the mechanism of platelet aggregation induced by HLA-related antibodies from nine patients. Antibody to platelet FcyRIIa failed to block platelet aggregation with 8/9 samples, indicating that engagement of platelet FcyRIIa is not necessary for the platelet aggregation induced by HLA-related antibodies. In contrast, platelet aggregation was blocked by antibodies to human C8 (5/7) or C9 (7/7). F(ab’)2 fragments of patient IgG failed to induce platelet activation although they bound to HLA antigen on platelets. Intact patient IgG failed to aggregate washed platelets unless aged serum was added. The activating IgG could be adsorbed by incubation with lymphocytes and eluted from the lymphocytes. These results indicate that complement activation is involved in the aggregation response to HLA-related antibodies. This is the first demonstration of complement-mediated platelet aggregation by clinical samples. Five of the patients developed thrombocytopenia in relationship to blood transfusion and two patients developed acute thromboembolic disease, suggesting that these antibodies and the complement-dependent pathway of platelet aggregation may be of clinical significance.


1985 ◽  
Vol 54 (04) ◽  
pp. 842-848 ◽  
Author(s):  
Kandice Kottke-Marchant ◽  
James M Anderson ◽  
Albert Rabinovitch ◽  
Richard A Huskey ◽  
Roger Herzig

SummaryHeparin is known to affect platelet function in vitro, but little is known about the effect of heparin on the interaction of platelets with polymer surfaces in general, and vascular graft materials in particular. For this reason, the effect of heparin vs. citrate anticoagulation on the interaction of platelets with the vascular graft materials expanded polytetrafluoroethylene (ePTFE), Dacron Bionit (DB) and preclotted Dacron Bionit (DB/PC) was studied in a recirculating, in vitro perfusion system. Platelet activation, as shown by a decrease in platelet count, an increase in platelet release and a decrease in platelet aggregation, was observed for all vascular graft materials tested using heparin and was greater for Dacron and preclotted Dacron than for ePTFE. Significant differences between heparin and citrate anticoagulation were seen for platelet release, platelet aggregation and the relative ranking of material platelet-reactivity. However, the trends and time course of platelet activation were similar with both heparin and citrate for the materials tested.


Biomedicines ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 965
Author(s):  
Grazia Maugeri ◽  
Agata Grazia D’Amico ◽  
Salvatore Saccone ◽  
Concetta Federico ◽  
Daniela Maria Rasà ◽  
...  

Pituitary adenylate cyclase-activating polypeptide (PACAP) exerts different effects in various human cancer. In glioblastoma (GBM), PACAP has been shown to interfere with the hypoxic micro-environment through the modulation of hypoxia-inducible factors via PI3K/AKT and MAPK/ERK pathways inhibition. Considering that hypoxic tumor micro-environment is strictly linked to angiogenesis and Epithelial–Mesenchymal transition (EMT), in the present study, we have investigated the ability of PACAP to regulate these events. Results have demonstrated that PACAP and its related receptor, PAC1R, are expressed in hypoxic area of human GBM colocalizing either in epithelial or mesenchymal cells. By using an in vitro model of GBM cells, we have observed that PACAP interferes with hypoxic/angiogenic pathway by reducing vascular-endothelial growth factor (VEGF) release and inhibiting formation of vessel-like structures in H5V endothelial cells cultured with GBM-conditioned medium. Moreover, PACAP treatment decreased the expression of mesenchymal markers such as vimentin, matrix metalloproteinase 2 (MMP-2) and matrix metalloproteinase 9 (MMP-9) as well as CD44 in GBM cells by affecting their invasiveness. In conclusion, our study provides new insights regarding the multimodal role of PACAP in GBM malignancy.


Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2248 ◽  
Author(s):  
Jian-Ming Chen ◽  
Pei-Yin Chen ◽  
Chia-Chieh Lin ◽  
Ming-Chang Hsieh ◽  
Jen-Tsun Lin

Background: Sesamin is a lignin present in sesame oil from the bark of Zanthoxylum spp. Sesamin reportedly has anticarcinogenic potential and exerts anti-inflammatory effects on several tumors. Hypothesis/Purpose: However, the effect of sesamin on metastatic progression in human head and neck squamous carcinoma (HNSCC) remains unknown in vitro and in vivo; hence, we investigated the effect of sesamin on HNSCC cells in vitro. Methods and Results: Sesamin-treated human oral cancer cell lines FaDu, HSC-3, and Ca9-22 were subjected to a wound-healing assay. Furthermore, Western blotting was performed to assess the effect of sesamin on the expression levels of matrix metalloproteinase (MMP)-2 and proteins of the MAPK signaling pathway, including p-ERK1/2, P-p38, and p-JNK1/2. In addition, we investigated the association between MMP-2 expression and the MAPK pathway in sesamin-treated oral cancer cells. Sesamin inhibited cell migration and invasion in FaDu, Ca9-22, and HSC-3 cells and suppressed MMP-2 at noncytotoxic concentrations (0 to 40 μM). Furthermore, sesamin significantly reduced p38 MAPK and JNK phosphorylation in a dose-dependent manner in FaDu and HSC-3 cells. Conclusions: These results indicate that sesamin suppresses the migration and invasion of HNSCC cells by regulating MMP-2 and is thus a potential antimetastatic agent for treating HNSCC.


1987 ◽  
Author(s):  
G Grignani ◽  
L Pacchiarini ◽  
M Zucchella ◽  
L Dezza ◽  
S C Rizzo

The mechanisms of platelet activation by human tumour cells grown “in vitro” or freshly dissociated from tumour tissues have been investigated.MoCCL human T-lymphoblastic cells cultured “in vitro” induced platelet aggregation through the production of ADP, as evidenced by inhibition of the effect by apyrase. The maximum of ADP production by tumour cells was reached after 1 hour and was 225 p moles/106 cells.On the contrary, platelet aggregation induced by 5637 human bladder carcinoma cells was not inhibited by apyrase, but was abolished by hirudin, indicating the important role of thrombin in this effect.Tumour cells dissociated from 3 breast carcinomas showed a very high platelet aggregating activity, which was not inhibited by hirudin or apyrase, but was abolished by iodoacetic acid, suggesting a role for a cystein-protease in platelet activation.These results confirm that platelets can be activated by tumour cells through different mechanisms; they also suggest that the methods employed to obtain the tumour cells can influence the results, probably because of the different cell populations which are present in the dissociated tumour tissues.Informations obtained with freshly dissociated cells are interesting, because this method has been used seldom so far and because it provides a more physiological approach to the study of the interactions of tumours and platelets.


2009 ◽  
Vol 78 (3) ◽  
pp. 1012-1021 ◽  
Author(s):  
Rosane M. B. Teles ◽  
Rose B. Teles ◽  
Thais P. Amadeu ◽  
Danielle F. Moura ◽  
Leila Mendonça-Lima ◽  
...  

ABSTRACT Gelatinases A and B (matrix metalloproteinase 2 [MMP-2] and MMP-9, respectively) can induce basal membrane breakdown and leukocyte migration, but their role in leprosy skin inflammation remains unclear. In this study, we analyzed clinical specimens from leprosy patients taken from stable, untreated skin lesions and during reactional episodes (reversal reaction [RR] and erythema nodosum leprosum [ENL]). The participation of MMPs in disease was suggested by (i) increased MMP mRNA expression levels in skin biopsy specimens correlating with the expression of gamma interferon (IFN-γ) and tumor necrosis factor alpha (TNF-α), (ii) the detection of the MMP protein and enzymatic activity within the inflammatory infiltrate, (iii) increased MMP levels in patient sera, and (iv) the in vitro induction of MMP-9 by Mycobacterium leprae and/or TNF-α. It was observed that IFN-γ, TNF-α, MMP-2, and MMP-9 mRNA levels were higher in tuberculoid than lepromatous lesions. In contrast, interleukin-10 and tissue inhibitor of MMP (TIMP-1) message were not differentially modulated. These data correlated with the detection of the MMP protein evidenced by immunohistochemistry and confocal microscopy. When RR and ENL lesions were analyzed, an increase in TNF-α, MMP-2, and MMP-9, but not TIMP-1, mRNA levels was observed together with stronger MMP activity (zymography/in situ zymography). Moreover, following in vitro stimulation of peripheral blood cells, M. leprae induced the expression of MMP-9 (mRNA and protein) in cultured cells. Overall, the present data demonstrate an enhanced MMP/TIMP-1 ratio in the inflammatory states of leprosy and point to potential mechanisms for tissue damage. These results pave the way toward the application of new therapeutic interventions for leprosy reactions.


2018 ◽  
Vol 50 (5) ◽  
pp. 1779-1793 ◽  
Author(s):  
Xiang Wang ◽  
Yun-Feng Fu ◽  
Xiao Liu ◽  
Guo Feng ◽  
Dan Xiong ◽  
...  

Background/Aims: Oxidized low-density lipoprotein (oxLDL) promotes unregulated platelet activation in patients with dyslipidemic disorders. Although oxLDL stimulates activating signaling, researchers have not clearly determined how these events drive accelerated thrombosis. Here, we describe the mechanism by which ROS regulate autophagy during ox-LDL-induced platelet activation by modulating the PI3K/AKT/mTOR signaling pathway. Methods: For in vitro experiments, ox-LDL, the ROS scavenger N-acetylcysteine (NAC), the mTOR inhibitor rapamycin and the autophagy inhibitor 3-MA were used alone or in combination with other compounds to treat platelets. Then, platelet aggregation was evaluated on an aggregometer and platelet adhesion was measured under shear stress. The levels of a platelet activation marker (CD62p) were measured by flow cytometry, reactive oxygen species (ROS) levels were then quantified by measuring DCFH-DA fluorescence intensity via flow cytometry. Nitric oxide (NO) and superoxide (O2·-) levels were determined by the nitric acid deoxidize enzyme method and lucigenin-enhanced chemiluminescence (CL), respectively. Transmission electron microscopy was used to observe the autophagosome formation, immunofluorescence staining was employed to detect LC3 expression and western blotting was used to measure the levels of PI3K/AKT/mTOR pathway- and autophagy-related proteins. Results: Ox-LDL-induced platelets showed a significant increase in platelet aggregation and adhesion, CD62p expression, ROS level and O2·- content, with an elevated LC3II/LC3I ratio and Beclin1 expression, but a dramatic reduction in the levels of p62 and pathway-related proteins (all P < 0.05). However, platelet activation and autophagy were aggravated by the Rapamycin treatment, and decreased following treatment with NAC, 3-MA, or NAC and 3-MA, together with increased activity of the PI3K/AKT/mTOR pathway. Additionally, decreased platelet activation and autophagy were observed in platelets treated with NAC and Rapamycin or Rapamycin and 3-MA compared with platelets treated with Rapamycin alone, suggesting that both NAC and 3-MA reversed the effects of Rapamycin. Conclusion: Inhibition of ROS production may reduce autophagy to suppress ox-LDL-induced platelet activation by activating PI3K/AKT/mTOR pathway.


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