Heterogeneity of serum gelatinases MMP‐2 and MMP‐9 isoforms and charge variants

The matrix metalloproteinases (MMPs) gelatinase A (MMP‐2) and gelatinase B (MMP‐9) are mediators of brain injury in multiple sclerosis (MS) and valuable biomarkers of disease activity. We applied bidimensional zymography (2‐DZ) as an extension of classic monodimensional zymography (1‐DZ) to analyse the complete pattern of isoforms and post‐translational modifications of both MMP‐9 and MMP‐2 present in the sera of MS patients. The enzymes were separated on the basis of their isoelectric points (pI) and apparent molecular weights (Mw) and identified both by comparison with standard enzyme preparations and by Western blot analysis. Two MMP‐2 isoforms, and at least three different isoforms and two different states of organization of MMP‐9 (the multimeric MMP‐9 and the N‐GAL‐MMP‐9 complex) were observed. In addition, 2‐DZ revealed for the first time that all MMP‐9 and MMP‐2 isoforms actually exist in the form of charge variants: four or five variants in the N‐GAL complex, more charge variants in the case of MMP‐9; and five to seven charge variants for MMP‐2. Charge variants were also observed in recombinant enzymes and, after concentration, also in sera from healthy individuals. Sialylation (MMP‐9) and phosphorylation (MMP‐2) contributed to molecular heterogeneity. The detection of charge variants of MMP‐9 and MMP‐2 in MS serum samples illustrates the power of 2‐DZ and demonstrates that in previous studies MMP mixtures, rather than single molecules, were analysed. These observations open perspectives for better diagnosis and prognosis of many diseases and need to be critically interpreted when applying other methods for MS and other diseases.     

The expression of MMP‐1 and MMP‐9 is up‐regulated by smooth muscle cells after their cross‐talk with macrophages in high glucose conditions

Patients with diabetes mellitus have an increased risk of myocardial infarction and coronary artery disease‐related death, exhibiting highly vulnerable plaques. Many studies have highlighted the major role of macrophages (MAC) and smooth muscle cells (SMC) and the essential part of metalloproteases (MMPs) in atherosclerotic plaque vulnerability. We hypothesize that in diabetes, the interplay between MAC and SMC in high glucose conditions may modify the expression of MMPs involved in plaque vulnerability. The SMC‐MAC cross‐talk was achieved using trans‐well chambers, where human SMC were grown at the bottom and human MAC in the upper chamber in normal (NG) or high (HG) glucose concentration. After cross‐talk, the conditioned media and cells were isolated and investigated for the expression of MMPs, MCP‐1 and signalling molecules. We found that upon cross‐talk with MAC in HG, SMC exhibit: (i) augmented expression of MMP‐1 and MMP‐9; (ii) significant increase in the enzymatic activity of MMP‐9; (iii) higher levels of soluble MCP‐1 chemokine which is functionally active and involved in MMPs up‐regulation; (iv) activated PKCα signalling pathway which, together with NF‐kB are responsible for MMP‐1 and MMP‐9 up‐regulation, and (v) impaired function of collagen assembly. Taken together, our data indicate that MCP‐1 released by cell cross‐talk in diabetic conditions binds to CCR2 and triggers MMP‐1 and MMP‐9 over‐expression and activity, features that could explain the high vulnerability of atherosclerotic plaque found at diabetic patients.     

Role of sialic acid‐containing glycans of matrix metalloproteinase‐9 (MMP‐9) in the interaction between MMP‐9 and staphylococcal superantigen‐like protein 5

Staphylococcal superantigen‐like proteins (SSL) show no superantigenic activity but have recently been considered to act as immune suppressors. It was previously reported that SSL5 bound to P‐selectin glycoprotein ligand‐1 (PSGL‐1) and matrix metalloproteinase (MMP)‐9, leading to inhibition of leukocyte adhesion and invasion. These interactions were suggested to depend on sialic acid‐containing glycans of MMP‐9, but the roles of sialic acids in the interaction between SSL5 and MMP‐9 are still controversial. In the present study, we prepared recombinant glutathione S‐transferase‐tagged SSL5 (GST‐SSL5) and analyzed its binding capacity to MMP‐9 by pull‐down assay after various modifications of its carbohydrate moieties. We observed that GST‐SSL5 specifically bound to MMP‐9 from a human monocytic leukemia cell line (THP‐1 cells) and inhibited its enzymatic activity in a concentration‐dependent manner. After MMP‐9 was treated with neuraminidase, its binding activity towards GST‐SSL5 was markedly decreased. Furthermore, recombinant MMP‐9 produced by sialic acid‐deficient Lec2 mutant cells showed much lower affinity for SSL5 than that produced by wild‐type CHO‐K1 cells. Treatment of MMP‐9 with PNGase F to remove N‐glycan resulted in no significant change in the GST‐SSL5/MMP‐9 interaction. In contrast, the binding of GST‐SSL5 to MMP‐9 secreted from THP‐1 cells cultured in the presence of an inhibitor for the biosynthesis of O‐glycan (benzyl‐GalNAc) was weaker than the binding of GST‐SSL5 to MMP‐9 secreted from untreated cells. These results strongly suggest the importance of the sialic acid‐containing O‐glycans of MMP‐9 for the interaction of MMP‐9 with GST‐SSL5.

     

MMP‐2 and MMP‐9 as prognostic markers for the early detection of urinary bladder cancer

The present study assessed protein and gene expression levels of tissue inhibitor of metalloproteinase‐2 (TIMP‐2), matrix metalloproteinase‐2 (MMP‐2), and MMP‐9 in urine and blood samples of 50 patients with bladder carcinoma. The expression of TIMP‐2, MMP‐2, and MMP‐9 levels with tumor stage and grade was also assessed. Results showed that the expression levels of MMP‐2 and MMP‐9 in both blood and urine were significantly elevated in group 1 when compared with groups 2 and 3 healthy subjects. The discriminatory ability in the diagnosis of bladder carcinoma of MMP‐2 and MMP‐9 expression was confirmed by receiver operating characteristic curve analysis that revealed a sensitivity and specificity of 100%. MMP‐2 and MMP‐9 levels were not correlated with grade or stage of the tumor. With respect to TIMP‐2 blood and urine levels, results showed a significant decrease in gene expression levels in bladder carcinoma group, whereas, TIMP‐2 protein showed a significant increase in bladder carcinoma.     

Metformin ameliorates BSCB disruption by inhibiting neutrophil infiltration and MMP‐9 expression but not direct TJ proteins expression regulation

Blood‐spinal cord barrier (BSCB) disruption is a major process for the secondary injury of spinal cord injury (SCI) and is considered to be a therapeutic target for SCI. Previously, we demonstrated that metformin could improve functional recovery after SCI; however, the effect of metformin on BSCB is still unknown. In this study, we found that metformin could prevent the loss of tight junction (TJ) proteins at day 3 after SCI in vivo, but in vitro there was no significant difference of these proteins between control and metformin treatment in endothelial cells. This indicated that metformin‐induced BSCB protection might not be mediated by up‐regulating TJ proteins directly, but by inhibiting TJ proteins degradation. Thus, we investigated the role of metformin on MMP‐9 and neutrophils infiltration. Neutrophils infiltration is the major source of the enhanced MMP‐9 in SCI. Our results showed that metformin decreased MMP‐9 production and blocked neutrophils infiltration at day 1 after injury, which might be related to ICAM‐1 down‐regulation. Also, our in vitro study showed that metformin inhibited TNF‐α‐induced MMP‐9 up‐regulation in neutrophils, which might be mediated via an AMPK‐dependent pathway. Together, it illustrated that metformin prevented the breakdown of BSCB by inhibiting neutrophils infiltration and MMP‐9 production, but not by up‐regulating TJ proteins expression. Our study may help to better understand the working mechanism of metformin on SCI.     

IL‐17 induces osteoclastogenesis from human monocytes alone in the absence of osteoblasts,which is potently inhibited by anti‐TNF‐α antibody: A novel mechanism of osteoclastogenesis by IL‐17

IL‐17 is a proinflammatory cytokine crucial for osteoclastic bone resorption in the presence of osteoblasts or synoviocytes in rheumatoid arthritis. However, the role of IL‐17 in osteoclastogenesis from human monocytes alone remains unclear. Here, we investigated the role of IL‐17 in osteoclastogenesis from human monocytes alone and the direct effect of infliximab on the osteoclastogenesis induced by IL‐17. Human peripheral blood mononuclear cells (PBMC) were cultured for 3 days with M‐CSF. After non‐adherent cells were removed, IL‐17 was added with either infliximab or osteoprotegerin (OPG). Seven days later, adherent cells were stained for vitronectin receptor. On the other hand, CD11b‐positive monocytes purified from PBMC were also cultured and stained as described above. CD11b‐positive cells were cultured with TNF‐α and receptor activator of NF‐κB ligand (RANKL). In the cultures of both adherent cells and CD11b‐positive cells, IL‐17 dose‐dependently induced osteoclastogenesis in the absence of soluble‐RANKL. OPG or infliximab inhibited IL‐17‐induced osteoclastogenesis. Interestingly, in the culture of CD11b‐positive cells, the osteoclastogenesis was more potently inhibited by infliximab than by OPG. TNF‐α and RANKL synergistically induced osteoclastogenesis. The present study clearly demonstrated the novel mechanism by which IL‐17 directly induces osteoclastogenesis from human monocytes alone. In addition, infliximab potently inhibits the osteoclastogenesis directly induced by IL‐17. J. Cell. Biochem. 108: 947–955, 2009. © 2009 Wiley‐Liss, Inc.     

Inhibitory effect of the carnosine–gallic acid synthetic peptide on MMP‐2 and MMP‐9 in human fibrosarcoma HT1080 cells

Matrix metalloproteinases (MMPs) are a family of zinc‐dependent endopeptidases that degrade extracellular matrix components and play important roles in a variety of biological and pathological processes such as malignant tumor metastasis and invasion. In this study, we constructed carnosine–gallic acid peptide (CGP) to identify a better MMP inhibitor than carnosine. The inhibitory effects of CGP on MMP‐2 and MMP‐9 were investigated in the human fibrosarcoma (HT1080) cell line. As a result, CGP significantly decreased MMP‐2 and MMP‐9 expression levels without a cytotoxic effect. Moreover, CGP may inhibit migration and invasion in HT1080 cells through the urokinase plasminogen activator (uPA)–uPA receptor signaling pathways to inhibit MMP‐2 and MMP‐9. Based on these results, it appears that CGP may play an important role in preventing and treating several MMP‐2 and MMP‐9‐mediated health problems such as metastasis. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.     

IL‐35 recombinant protein reverses inflammatory bowel disease and psoriasis through regulation of inflammatory cytokines and immune cells

Interleukin‐35 (IL‐35), a member of the IL‐12 family, functions as a new anti‐inflammatory factor involved in arthritis, psoriasis, inflammatory bowel disease (IBD) and other immune diseases. Although IL‐35 can significantly prevent the development of inflammation in many diseases, there have been no early studies accounting for the role of IL‐35 recombinant protein in IBD and psoriasis. In this study, we assessed the therapeutic potential of IL‐35 recombinant protein in three well‐known mouse models: the dextransulfate sodium (DSS)‐induced colitis mouse model, the keratin14 (K14)‐vascular endothelial growth factor A (VEGF‐A)‐transgenic (Tg) psoriasis mouse model and the imiquimod (IMQ)‐induced psoriasis mouse model. Our results indicated that IL‐35 recombinant protein can slow down the pathologic process in DSS‐induced acute colitis mouse model by decreasing the infiltrations of macrophages, CD4⁺T and CD8⁺T cells and by promoting the infiltration of Treg cells. Further analysis demonstrated that IL‐35 recombinant protein may regulate inflammation through promoting the secretion of IL‐10 and inhibiting the expression of pro‐inflammatory cytokines such as IL‐6, TNF‐α and IL‐17 in acute colitis model. In addition, lower dose of IL‐35 recombinant protein could achieve long‐term treatment effects as TNF‐α monoclonal antibody did in the psoriasis mouse. In summary, the remarkable therapeutic effects of IL‐35 recombinant protein in acute colitis and psoriasis mouse models indicated that IL‐35 recombinant protein had a variety of anti‐inflammatory effects and was expected to become an effective candidate drug for the treatment of inflammatory diseases.     

Anti‐invasion effect of rosmarinic acid via the extracellular signal‐regulated kinase and oxidation–reduction pathway in Ls174‐T cells

Rosmarinic acid is a major phenylpropanoid isolated from Prunella vulgaris L., which is a composition of herbal tea for centuries in China. However, the anti‐invasion activity on Ls174‐T human colon carcinoma cells has not been studied. In this study, we investigated the anti‐metastasis functions according to wound healing assay, adhesion assay, and Transwell assay and found that rosmarinic acid could inhibit migration, adhesion, and invasion dose‐dependently. Rosmarinic acid also could decrease the level of reactive oxygen species by enhancing the level of reduced glutathione hormone. In addition, rosmarinic acid repressed the activity and expression of matrix metalloproteinase‐2,9. According to Western blot and quantitative real‐time PCR assay, rosmarinic acid may inhibit metastasis from colorectal carcinoma mainly via the pathway of extracellular signal‐regulated kinase. In animal experiment, intraperitoneal administration of 2 mg of rosmarinic acid reduced weight of tumors and the number of lung nodules significantly compared with those of control group. Therefore, these results demonstrated that rosmarinic acid can effectively inhibit tumor metastasis in vitro and in vivo. J. Cell. Biochem. 111: 370–379, 2010. © 2010 Wiley‐Liss, Inc.     

Type‐specific dysregulation of matrix metalloproteinases and their tissue inhibitors in end‐stage heart failure patients: relationship between MMP‐10 and LV remodelling

Although past studies observed the changes of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in end‐stage heart failure (HF) patients, a consistent and clear pattern of type‐specific MMPs and/or TIMPs has yet to be further defined. In this study, proteomic approach of human protein antibody arrays was used to compare MMP and TIMP expression levels of left ventricular (LV) myocardial samples from end‐stage HF patients due to dilated cardiomyopathy (DCM) with those from age‐ and sex‐ matched non‐failing patients. Western blot analysis, immunohistochemistry and ELISA were used for validation of our results. We observed that MMP‐10 and ‐7 abundance increased, accompanied by decreased TIMP‐4 in DCM failing hearts (n= 8) compared with non‐failing hearts (n= 8). The results were further validated in a cohort of 34 end‐stage HF patients derived from three forms of cardiomyopathies. Cardiac and plasma MMP‐10 levels were positively correlated with the LV end‐diastolic dimension in this HF cohort. In addition, we observed that insulin‐like growth factor‐2 promoted MMP‐10 production in neonatal rat cardiomyocytes. In conclusion, this study demonstrated a selective up‐regulation of MMP‐10 and ‐7 along with a discordant change of TIMP‐4, and a positive correlation between MMP‐10 levels and the degree of LV dilation in end‐stage HF patients. Our findings suggest that type‐specific dysregulation of MMPs and TIMPs is associated with LV remodelling in end‐stage HF patients, and MMP‐10 may act as a novel biomarker for LV remodelling.     

Enantiomeric 9‐mer peptide analogs of protaetiamycine with bacterial cell selectivities and anti‐inflammatory activities

Protaetiamycine is an insect defensin, derived from the larvae of the beetle Protaetia brevitarsis. In our previous work, we designed 9‐mer peptide analogs of protaetiamycine, including 9Pbw2 (RLWLAIKRR‐NH₂), 9Pbw3 (RLWLAIWRR‐NH₂), and 9Pbw4 (RLWLAWKRR‐NH₂). 9Pbw2 and 9Pbw4 showed high antimicrobial activity without cytotoxicity, while 9Pbw3 with higher hydrophobicity compared to 9Pbw2 and 9Pbw4 showed high cytotoxicity as well as high antimicrobial activity (Shin et al., J. Pept. Sci. 2009; 15: 559–568). In this study, we investigated the anti‐inflammatory activities of 9Pbw2, 9Pbw3, and 9Pbw4 by quantitation of NO production in LPS‐stimulated RAW264.7 cells. The results showed that only 9Pbw3 has strong inhibition of NO production, implying that Trp⁷ as well as optimum level of hydrophobicity may play key roles in the anti‐inflammatory activity of 9Pbw3. In order to design potent anti‐inflammatory peptide with lower cytotoxicity as well as high stability from cleavage by protease compared to 9Pbw3, we synthesized 9Pbw3‐D , the all‐D ‐amino acid analog of 9Pbw3. 9Pbw3‐D showed less cytotoxicity against RAW264.7 cells as well as considerably stronger inhibition of NO production and inflammation‐induced cytokine production in LPS‐stimulated RAW264.7 cells than 9Pbw3. 9Pbw3‐D inhibited the gene expression of inflammatory‐induced cytokine significantly more than 9Pbw3 and showed high resistance to proteolytic digestion. Binding of 9Pbw3‐D with LPS caused higher enhancement of the FITC fluorescence as a result of its stronger interaction with LPS compared to that of 9Pbw3 and this result is in good agreement with their anti‐inflammatory activities. 9Pbw3‐D with higher anti‐inflammatory activity as well as lower cytotoxicity against mammalian cell compared to 9Pbw3 can be a potent noncytotoxic antibiotic candidates. Copyright © 2011 European Peptide Society and John Wiley & Sons, Ltd.     

S100A9 gene silencing inhibits the release of pro‐inflammatory cytokines by blocking the IL‐17 signalling pathway in mice with acute pancreatitis

The study aimed to investigate whether S100A9 gene silencing mediating the IL‐17 pathway affected the release of pro‐inflammatory cytokines in acute pancreatitis (AP). Kunming mice were assigned to the normal, AP, AP + negative control (NC), AP + shRNA, AP + IgG and AP + anti IL‐17 groups. ELISA was applied to measure expressions of AMY, LDH, CRP, TNF‐α, IL‐6 and IL‐8. The cells were distributed into the control, blank, NC, shRNA1 and shRNA2 groups. MTT assay, flow cytometry, RT‐qPCR and Western blotting were used to evaluate cell proliferation, cell cycle and apoptosis, and expressions of S100A9, TLR4, RAGE, IL‐17, HMGB1 and S100A12 in tissues and cells. Compared with the normal group, the AP group displayed increased expressions of AMY, LDH, CRP, TNFα, IL‐6, IL‐8, S100A9, TLR4, RAGE, IL‐17, HMGB1 and S100A12. The AP + shRNA and AP + anti IL‐17 groups exhibited an opposite trend. The in vivo results: Compare with the control group, the blank, NC, shRNA1 and shRNA2 groups demonstrated increased expressions of S100A9, TLR4, RAGE, IL‐17, HMGB1 and S100A12, as well as cell apoptosis and cells at the G1 phase, with reduced proliferation. Compared with the blank and NC groups, the shRNA1 and shRNA2 groups had declined expressions of S100A9, TLR4, RAGE, IL‐17, HMGB1 and S100A12, as well as cell apoptosis and cells at the G1 phase, with elevated proliferation. The results indicated that S100A9 gene silencing suppressed the release of pro‐inflammatory cytokines through blocking of the IL‐17 pathway in AP.     

Chemiluminescence of non‐differentiated THP‐1 promonocytes: developing an assay for screening anti‐inflammatory milk proteins and peptides

Human leukemic THP‐1 promonocytes are widely used as a model for peripheral blood monocytes. However, superoxide production during respiratory burst (RB) of non‐differentiated THP‐1 (nd‐THP‐1) cells is very low. Here we present a rapid and low‐cost method for measuring the chemiluminescence (CL) of opsonized zymosan (OZ) induced RB which allows detection of Escherichia coli lipopolysaccharide (LPS) induced priming of nd‐THP‐1 cells on the basis of CL reaction kinetics. Maximum CL intensity obtained was 2.20 ± 0.25 and 1.30 ± 0.11 relative light units, while CL peak time was achieved at 18.1 ± 2.6 and 28.7 ± 1.3 min in primed and non‐primed cells, respectively. The priming of nd‐THP‐1 cells with LPS evoked typical TNF‐α and IL‐6 production. We tested the effects of bovine lactoferrin and protein fractions from Lactobacillus helveticus BGRA43 fermented milk for potential anti‐inflammatory effects on LPS primed nd‐THP‐1 cells. Four fractions were found to inhibit the OZ‐induced CL in a dose‐dependent manner (IC₅₀ 3–30 µg/mL), while lactoferrin inhibited CL to a lesser extent (IC₅₀ 270 µg/mL). These results suggest that measuring CL response of nd‐THP‐1 cells can serve as a method for screening anti‐inflammatory compounds which could be used in reducing the risk of phagocyte‐mediated inflammatory diseases. Copyright © 2010 John Wiley & Sons, Ltd.