Trichomonas vaginalis Metalloproteinase Induces mTOR Cleavage of SiHa Cells

Trichomonas vaginalis secretes a number of proteases which are suspected to be the cause of pathogenesis; however, little is understood how they manipulate host cells. The mammalian target of rapamycin (mTOR) regulates cell growth, cell proliferation, cell motility, cell survival, protein synthesis, and transcription. We detected various types of metalloproteinases including GP63 protein from T. vaginalis trophozoites, and T. vaginalis GP63 metalloproteinase was confirmed by sequencing and western blot. When SiHa cells were stimulated with live T. vaginalis, T. vaginalis excretory-secretory products (ESP) or T. vaginalis lysate, live T. vaginalis and T. vaginalis ESP induced the mTOR cleavage in both time- and parasite load-dependent manner, but T. vaginalis lysate did not. Pretreatment of T. vaginalis with a metalloproteinase inhibitor, 1,10-phenanthroline, completely disappeared the mTOR cleavage in SiHa cells. Collectively, T. vaginalis metallopeptidase induces host cell mTOR cleavage, which may be related to survival of the parasite.

Collagen I and III and metalloproteinase gene and protein expression in prostate cancer in relation to Gleason score

PURPOSE: To evaluate if the expression of metalloproteinase, collagen I and III are related to Gleason score, preoperative PSA and pathological stage in prostate cancer. MATERIALS AND METHODS: Our study group included radical prostatectomy specimens of 33 patients with prostatic adenocarcinoma who underwent surgery from 2001 to 2009. Patients were divided into 3 groups: Gleason score=6 (13 patients), Gleason score=7 (10 patients), Gleason score>8 (10 patients). The control group included prostates of patients submitted to cystoprostatectomy and benign prostatic tissues adjacent to the cancer area. Specific areas of tissues were selected under microscope and further processed for collagen I and III analysis by real time PCR. In addition, 10 deparaffined sections of each group were used to evaluate collagen I, III and metalloproteinase immune expression. The results were correlated with Gleason score, preoperative PSA and pathological stage. RESULTS: We found significant difference in both collagen I and III gene expression between benign and tumoral areas in the prostate samples from Gleason score=6 (collagen I=0.4±0.2 vs 5±2.4, p<0.05; collagen III=0.2±0.06 vs 0.7±0.1, p<0.05) and Gleason score>8 (collagen I=8±3.4 vs 1.4±0.8, p<0.07; collagen III=1.8±0.5 vs 0.6±0.1, p<0.05). There was no correlation of collagen expression with Gleason score, preoperative PSA or pathological stage. There was a positive correlation between metalloproteinase expression and Gleason score (r²=0.47). CONCLUSIONS: The positive correlation between metalloproteinase expression and Gleason score suggests that metalloproteinase could be a promising factor to improve Gleason score evaluation. Its expression and regulation do not seem to be related with collagen degradation.

Evolutionary histories of expanded peptidase families in Schistosoma mansoni

Schistosoma mansoni is one of the three main causative agents of human schistosomiasis, a major health problem with a vast socio-economic impact. Recent advances in the proteomic analysis of schistosomes have revealed that peptidases are the main virulence factors involved in the pathogenesis of this disease. In this context, evolutionary studies can be applied to identify peptidase families that have been expanded in genomes over time in response to different selection pressures. Using a phylogenomic approach, we searched for expanded endopeptidase families in the S. mansoni predicted proteome with the aim of contributing to the knowledge of such enzymes as potential therapeutic targets. We found three endopeptidase families that comprise leishmanolysins (metallopeptidase M8 family), cercarial elastases (serine peptidase S1 family) and cathepsin D proteins (aspartic peptidase A1 family). Our results suggest that the Schistosoma members of these families originated from successive gene duplication events in the parasite lineage after its diversification from other metazoans. Overall, critical residues are conserved among the duplicated genes/proteins. Furthermore, each protein family displays a distinct evolutionary history. Altogether, this work provides an evolutionary view of three S. mansoni peptidase families, which allows for a deeper understanding of the genomic complexity and lineage-specific adaptations potentially related to the parasitic lifestyle.

The metalloproteinase of Leishmania: leishmanolysin

Zinc metalloproteinases are a diverse group of endo- and exoproteinases related only by their common catalytic mechanism and similar primary structure defining the metal binding domain. They are involved in tissue remodelling, metastasis, peptide hormone processing and digestion. Outside of the zinc binding site, their primary structures are highly divergent, suggesting that this group of enzymes is the product of convergent evolution. The three dimensional structures of small soluble bacterial (thermolysin) and eukaryote (astacin) metalloproteinases has allowed the establishment of several families of metalloproteinases based upon the zinc binding ligands of the enzymes. Thus far, no high-molecular weight membrane bound metalloproteinase has been crystallised; unfortunately these are among the most interesting in terms of human physiology. Leishmanolysin, the abundant surface metalloproteinase of several genera of kinetoplastid protozoans, most notably Leishmania, provides an abundant source of glycophosphatidylinositol-anchored glycoprotein for biochemical and structural studies, which will not only lead to a better understanding of the role of the proteinase in the life cycle of the protozoan, but will also provide a framework upon which to model the structures of mammalian metalloproteinases.