Proteases and their inhibitors in chronic inflammatory periodontal disease

This article reviews the current knowledge of the sources, function and interactions of proteolytic enzymes and their inhibitors in chronic inflammatory periodontal disease. Proteolytic tissue degradation is a typical phenomenon in chronic inflammatory periodontal disease. The proteolytic enzymes can be both host- and bacteria-derived. The proteases of the inflammatory cells are aimed for digestion of bacteria, enhanced locomotion through connective tissue, demarcation of the site of infection and tissue remodeling. Uncontrolled release of proteases in inflammation causes self-digestion and tissue destruction. The potential of the bacterial proteases in degradation of connective tissue is not yet known. Biochemical and immunologic mediators of inflammation are released by proteolytic reactions. Immunoglobulin-cleaving proteases present a specific mechanism in perturbation of host defenses. The 2 main protease inhibitors in serum, alpha-1-antitrypsin and alpha-2-macroglobulin, are also present in the gingival tissue fluid guarding the function of proteases. It has been suggested, although not confirmed, that deficiency in serum protease inhibiting capacity could be correlated with susceptibility to periodontal disease. Mucous secretions contain local low molecular weight protease inhibitors, but their possible r?le in saliva is not known. Bacteria-derived, antiproteolytic short peptides may prove to be useful in pharmacological control of tissue destruction at inflammatory sites.     

Effect of aprotinin, EACA and heparin on growth and vasopeptide system of Murphy-Sturm lymphosarcoma.

The effect of aprotinin, EACA and heparin on the growth of the transplanted rodent Murphy-Sturm lymphosarcoma and on several components of the tumor kinin-forming enzyme system was studied. Therapy was administered for 15 days, 3 times daily, one day after tumor transplant. Tumor weights and biochemical parameters (prekallikrein, kininogen and kininase) were measured on the 8th, 10th, 12th and 15th day of therapy. Both aprotinin and heparin significantly inhibited (p less than 0.01) tumor growth by the 15th day, compared to control, saline-administered animals. EACA did not affect the tumor growth rate at any time period. Tumor prekallikrein and kininogen levels were significantly higher (p less than 0.01) in the aprotinin-treated animals. Kininogen levels were higher in the EACA-treated tumors during the latter phase of growth. None of the agents affected the increase in tumor kininase activity that occured during the growth of the tumors. The tumor inhibition and biochemical data suggest the involvement of proteases in the neoplastic process.     

Phytochemistry and pharmacological activities of Ficus carica latex: a systematic review

Ficus carica tree produces a white sap that is traditionally used for the treatment of skin conditions, such as warts. Ficus carica latex is considered a rich source of proteins and metabolites that have various pharmacological activities. Most of the latex pharmacological activities are attributed to its phenolic content, such as anticancer, antiviral, antioxidant, anti-angiogenic, hepatoprotective, and wound-healing activities. Moreover, Ficus carica latex contains proteases that are involved in the treatments of skin conditions, such as warts, and display antiparasitic activity. Additionally, chitinase enzymes and coumarins are isolated from Ficus carica latex and involved in the antimicrobial activities of latex.     

Multiple routes of complement activation by Mycobacterium bovis BCG

Mycobacterium tuberculosis is the leading cause of infectious disease in humans in the world. It evades the host immune system by being phagocytosed by macrophages and residing intracellularly. Complement-dependent opsonisation of extracellular mycobacteria may assist them to enter macrophages. This work examines in detail the mechanisms of complement activation by whole mycobacteria using Mycobacterium bovis BCG as a model organism. M. bovis BCG directly activates the classical, lectin and alternative pathways, resulting in fixation of C3b onto macromolecules of the mycobacterial surface. Investigation into the classical pathway has shown direct binding of human C1q to whole mycobacteria in the absence of antibodies. Most human sera contain IgG and IgM-anti-(M. bovis BCG), and pre-incubation with human immunoglobulin enhances C1q binding to the bacteria. Therefore classical pathway activation is both antibody-independent and dependent. The bacteria also activate the alternative pathway in an antibody-independent manner, but Factor H also binds, suggesting some regulation of amplification by this pathway. For the lectin pathway we have demonstrated direct binding of both MBL and L-ficolin from human serum to whole mycobacteria and subsequent MASP2 activation. H-ficolin binding was not observed. No M. bovis BCG cell surface or secreted protease appears likely to influence complement activation. Together, these data provide a more detailed analysis of the mechanisms by which M. bovis BCG interacts with the complement system.     

Proteolytic enzyme activities of macrophages and lymphocytes in neurological diseases

Summary Studies showed a significant decrease in the macrophage neutral protease and lymphocyte acid protease activities in patients with multiple sclerosis in remission, a significantly decreased neutral protease activity in macrophages in patients with myasthenia gravis and a significantly decreased acid protease activity in macrophages and lymphocytes in patients with polymyositis. No remarkable abnormalities were found in patients with myotonic dystrophy. These results suggest that multiple sclerosis, myasthenia gravis and polymyositis have an abnormality in immunological function.     

Granulocyte elastase-mediated proteolysis of alpha 1-antitrypsin in cystic fibrosis bronchopulmonary secretions

Airway secretions of patients with cystic fibrosis (CF) contain large amounts of alpha 1-antitrypsin (alpha 1-AT), yet elastase activity is also often detectable, suggesting that airway alpha 1-AT may not be functional in some CF patients. It is unknown whether in CF sputum alpha 1-AT is inactivated by oxidants, neutrophil metalloproteinases, bacterial elastase, or neutrophil elastase. To investigate the mechanism(s) by which alpha 1-AT may be inactivated in CF airway secretions, sputum samples were obtained from nine patients during respiratory physiotherapy. alpha 1-AT was measured by radial immunodiffusion. Sputum-alpha 1-AT was purified by antibody affinity chromatography. Electrophoresis of alpha 1-AT from seven patients with acute infectious exacerbations revealed two distinct components: a minor band corresponding to an elastase/alpha 1-AT complex and a major band typical of proteolysed alpha 1-AT (Mr = 48 kD). Each patient had large amounts of sputum elastase activity. In contrast, two patients without free sputum elastase activity had intact sputum alpha 1-AT; however, alpha 1-AT was partially truncated by porcine pancreatic elastase suggesting that the alpha 1-AT may have been partially oxidized. Adding alpha 1-AT purified from normal serum to alpha 1-AT-depleted sputum containing elastase activity resulted in a small alpha 1-AT/elastase complex with most alpha 1-AT being truncated. The serine proteinase inhibitor phenylmethylsulfonyl fluoride but not the metalloproteinase inhibitor EDTA prevented alpha 1-AT proteolysis, thus granulocyte elastase can mediate alpha 1-AT degradation in CF. Apparently, the large granulocyte elastase burden in some acutely ill patients with cystic fibrosis can proteolytically inactivate alpha 1-AT.     

Protease-activated receptors

Certain serine proteases from the circulation (e.g., coagulation factors), inflammatory cells (e.g., mast-cell tryptase, neutrophil proteinase 3), and from many other cell types (e.g., trypsins) can specifically signal to cells by cleaving protease-activated receptors (PARs), a family of four G protein-coupled receptors. Proteases cleave PARs at specific sites within the extracellular amino-terminus to expose amino-terminal tethered ligand domains that bind to and activate the cleaved receptors. The proteases that activate PARs are often generated and released during injury and inflammation, and activated PARs orchestrate tissue responses to injury, including hemostasis, inflammation, pain, and repair. This review concerns protease and PAR signaling in the nervous system. Neurons of the central and peripheral nervous systems express all four PARs. Proteases that may derive from the circulation, inflammatory cells, or neural tissues can cleave PARs on neurons and thereby activate diverse signaling pathways that control survival, morphology, release of neurotransmitters, and activity of ion channels. In this manner proteases and PARs regulate neurodegeneration, neurogenic inflammation, and pain transmission. Thus, PARs may participate in disease states and PAR antagonists or agonists may be useful therapies for certain disorders.     

Evaluation of serum cathepsin B and D in relation to clinicopathological staging of colorectal cancer

AIM: Proteolytic degradation of the extracellular matrix facilitates cancer invasion and promotes metastasis. The study aims at evaluation of preoperative and postoperative serum cathepsins B and D levels in correlation with selected anatomoclinical features of colorectal cancer. METHODS: Blood samples were collected from 63 colorectal cancer patients before curative operation of the tumor 10 d later. Blood that was obtained from 20 healthy volunteers, served as a control. The activity of cathepsin B was measured with Bz-DL-arginine-pNA as a substrate at pH 6.0, while cathepsin D activity was determined with urea-denatured hemoglobin (pH 4.0). RESULTS: The preoperative and postoperative activities of cathepsin B were significantly (P<0.00001) lower in serum of colorectal cancer patients than in control group. However, postoperative values of this protease were significantly increased in comparison with preoperative ones (P = 0.031). Activity of cathepsin D appeared to be significantly higher in colorectal cancer sera (P<0.00001) compared with controls. No statistically significant differences between preoperative and postoperative activity of cathepsin D were noted (P = 0.09). We revealed a strong linkage of cathepsins' levels with lymph node status and pT stage of colorectal cancer. CONCLUSION: Blood serum activities of cathepsin B and D depend on the time of sampling, tumor size and lymph node involvement. Significantly, increased activity of cathepsin D could indicate a malignant condition of the large intestine. In our work, the serum postoperative decrease of cathepsin B activity appears as an obvious concomitant of local lymph node metastasis-the well-known clinicopathological feature of poor prognosis.