Does Outcome/Survival of Patients With Myelodysplastic Syndromes Should Be Predicted by Reduced Levels of ADAMTS-13? Results From a Pilot Study

IntroductionVon Willebrand factor (vWF) cleaving protease ADAMTS-13 has a key role for maintaining normal size of vWF. A deficiency or dysfunction of vWF cleaving protease is associated with ultra large vWF multimers and thrombotic microangiopathy. Patients with cancers have reduced levels of vWF cleaving protease. In this pilot study, we have evaluated whether or not deficiencies of ADAMTS-13 were present in myelodysplastic syndromes (MDS). Moreover, we assessed if a reduction in basal levels of ADAMTS-13 may play a role in the prognosis of MDS.Patients and MethodsWe measured and compared the levels of vWF cleaving protease ADAMTS-13 in 100 patients with MDS and 35 healthy controls. Patients were divided into 2 groups according to the International Prognostic Scoring System: group I consisting of 44 patients with low-risk MDS and group II of 56 patients with high-risk MDS. Patients with high-risk and low-risk MDS presented significantly lower levels of ADAMTS-13 than controls (P < .001 and P = .0177, respectively). High-risk patients had significantly lower levels of ADAMTS-13 when compared with the low-risk group (P < .001).ResultsWe found that reduced levels of ADAMTS-13 have a relationship with overall survival (P < .001). Statistical analysis showed that ADAMTS-13 correlates with cytogenetics (P < .001) and a tendency of slight correlation with platelet count and basal levels of ADAMTS-13 (R, 0.35; P value, 0.001). Moreover, we found that levels of ADAMTS-13 have correlation with response to treatment (P < .001).ConclusionsADAMTS-13 in MDS might represent a surrogate marker of prognosis, response to therapy, or disease progression. Further studies are needed.     

A novel metalloprotease from Vipera lebetina venom induces human endothelial cell apoptosis.

A novel endothelial cell apoptosis inducing metalloprotease (VLAIP) was found in the snake venom of Vipera lebetina. This metalloprotease is a heterodimeric glycoprotein with molecular mass of about 106 kDa. The protease hydrolyzes azocasein, fibrinogen and oxidized insulin B-chain. The enzyme readily hydrolyzes the Aalpha-chain and more slowly Bbeta-chain of fibrinogen. VLAIP does not cleave fibrin. The complete amino acid sequences of the two different monomers of VLAIP are deduced from the nucleotide sequences of cDNAs encoding these proteins. The full-length cDNA sequences of the VLAIP-A and VLAIP-B encode open reading frames of 616 and 614 amino acids that include signal peptide, propeptide and mature metalloproteinase with disintegrin-like and cysteine-rich domains. VLAIP belongs to the metalloprotease/disintegrin family of reprolysins and has high identity with the proteins that induce apoptosis of endothelial cells. Treatment of HUVEC cells with VLAIP induces changes in the attachment of cells to the substrate and causes cell death. We demonstrated that VLAIP inhibits endothelial cell adhesion to extracellular matrix proteins: fibrinogen, fibronectin, vitronectin, collagen I, and collagen IV. The induction of apoptosis by VLAIP was shown by means of a typical DNA fragmentation pattern of apoptotic cells as well as by monitoring phosphatidylserine externalization using annexin V-FITC staining and flow cytometric analysis.     

ADAM10、ADAM17的作用和miRNA的调节在腹主动脉瘤发病机制中的研究进展

腹主动脉瘤(AAA)是一种病死率极高的急症,因发病机制复杂,至今病因尚未明确。近年来研究发现,去整合素和金属蛋白酶(ADAM)家族参与促进炎性因子的释放、细胞外基质降解等特性可能与AAA发病有关;mi RNA在血管平滑肌细胞中特异性表达并通过信号通路调节其增殖和凋亡、靶向调控炎性细胞分化和炎性因子的释放、调节细胞外基质蛋白表达等可能也参与调节AAA发病。笔者就ADAM10和ADAM17在AAA发病机制中作用和mi RNA对AAA发病调节做一综述。     

Chitin from the Extract of Cuttlebone Induces Acute Inflammation and Enhances MMP1 Expression

We previously reported that the extract from cuttlebone (CB) has wound healing effect in burned lesion of rat. In present study, the main component of CB extract was analyzed and its wound healing activity was evaluated by using in vitro acute inflammation model. The extract of CB stimulated macrophages to increase the production of TNF-α. The extract also enhanced the production of TGF-β and VEGF, which were involved in angiogenesis and fibroblast activation. The treatment with CB extract enhanced proliferation of murine fibroblast. CB extract also induced the activation of fibroblast to increase the secretion of matrix metalloproteases 1 (MMP1). The constituent of CB extract which has wound healing activity was identified as chitin by HPLC analysis. The mechanism that the CB extract helps to promote healing of burned lesion is associated with that chitin in CB extracts stimulated wound skins to induce acute inflammation and to promoted cell proliferation and MMP expression in fibroblast. Our results suggest that CB or chitin can be a new candidate material for the treatment of skin wound such as ulcer and burn.     

Neutral metalloprotease from tendons

Tendon repair following trauma, rupture, or surgery involves both synthesis and degradation of collagen in order to reweave new collagen bundles in with the old. Using an in situ assay on polyacrylamide gels containing gelatin, we have identified protease activity from tendon tissue and from tendon cells in culture. A population of synovial cells from the epitenon surrounding the tendon as well as the tendon fibroblasts themselves were examined. The cells and the conditioned medium from both cell populations exhibited a major band of gelatin-degrading activity at 70 kdaltons and a minor band of activity at 60 kdaltons. When preparations were reacted with p-aminophenylmercuric acetate (APMA) before electrophoresis, a third band appeared at 63 kdaltons. The main band at 70 kdaltons comigrated with a [35S]methionine-radiolabeled protein band. Inhibitor and pH studies identified the enzymes as neutral metalloproteases requiring disulfide bonds for activity. No proteolytic activity was detected on casein-containing gels, ruling out the presence of stromelysin. Since electrophoresis in the presence of SDS would separate the metalloprotease from the smaller molecular weight inhibitor (TIMP), these in situ assays provide a sensitive screening system for gelatin-degrading enzymes present in tendon without prior removal of TIMP.     

Hepatic expression of A disintegrin and metalloproteinase (ADAM) and ADAMs with thrombospondin motives (ADAM-TS) enzymes in patients with chronic liver diseases

BACKGROUND/AIMS: ADAMs (A Disintegrin And Metalloprotease) are multifunctional, membrane-bound and soluble cell surface glycoproteins with numerous functions in cell physiology. We assessed the expression of ADAMs in fibrotic liver disease of different aetiologies and clarified whether the expression of ADAMs is related to histological staging of fibrosis. In addition, the expression of ADAMs was determined in different cell types of liver. METHODS: Seventy-one biopsy samples from patients with chronic liver diseases were analyzed for mRNA expression of ADAM-8, -9, -12, -28, -TS1, -TS2, matrix metalloprotease (MMP)-2, -9 and tissue inhibitor of metalloproteinases-1 and -2 by quantitative real-time RT-PCR. RESULTS: The ADAM expression in liver injury is independent of aetiology. A strong correlation between ADAM -9, -28, -TS1 versus MMP-2 and SMA was identified. Activated hepatic stellate cells (HSC) showed increased mRNA expression of ADAM-8, -9, -12, -28, -TS2 compared to quiescent HSC. Significant differences between histological stages of fibrosis were found for ADAM-28, MMP-2 and MMP-9. CONCLUSIONS: The results suggest that ADAMs are differentially expressed in the liver. We assume that ADAM-9, -TS1 and -TS2 play a crucial role in extracellular matrix remodeling during fibrotic processes in the liver.     

Expression of mRNAs coding for VAP1/crotastatin-like metalloproteases in the venom glands of three South American pit vipers assessed by quantitative real-time PCR

Snake venom metalloproteases encompass a large family of toxins, with approximately 200 members already catalogued, which exhibit a diversity of structures and biological functions. From this relatively large number, only a dozen examples of apoptosis-inducing metalloproteases, like VAP1 and 2 from the venom of Crotalus atrox, are known. Since most VAP1-like toxins ever characterized were purified from the venom of Viperidae species inhabiting diverse places on earth, we investigate the expression of VAP-like metalloproteases in the venom gland of three representative pit vipers of the Brazilian territory. By molecular cloning and quantitative real-time polymerase chain reaction, using as calibrator gene the Crotalus durissus terrificus homolog of VAP1, named crotastatin, it is reported here that VAP1/crotastatin-like homologues in the venom gland of Bothrops atrox, C. d. cascavella and Lachesis m. rhombeata are expressed at different levels. Hence, batroxstatins, the crotastatin-like precursors from B. atrox, are expressed 87 times more than crotastatin-1, from C. d. cascavella, and 7.5-fold that lachestatins, from L. m. rhombeata. Moreover, in silico structural analysis of amino acid sequences indicates that batroxstatin-2, crotastatins and lachestatin-1 and -2 which share the archetypal motifs and metal- binding sites of VAP1, are subgrouped in a branch that comprises some apoptosis-inducing toxins.     

Identification of novel polymorphisms in the<Emphasis Type="Italic"> Adam33</Emphasis> gene

Adam33 is a member of a family of genes that encode membrane-anchored proteins with a disintegrin and a metalloprotease domain and that are primarily expressed in lung fibroblasts and bronchial smooth muscle. The human Adam33 gene is located on chromosome 20p13, a region that has been linked to asthma and bronchial hyperresponsiveness. Recently, the polymorphisms in Adam33 have been found to be associated with asthma. In this study, we performed polymorphism scanning of the entire genomic region, including the promoter region of Adam33, by direct sequencing. We identified 16 novel polymorphisms in the Adam33 gene. Among these novel polymorphisms, three polymorphisms (−2154G→A, −753T→A, and −330C→T) were found to be in the promoter region and one polymorphism (13491 G→A) was located in 3' untranslated region of the Adam33 gene. Electronic Publication