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In recent years, it has been discovered that many membrane elements in cells are crucial for homeostasis and constitute a pivotal, previously ignored, element of immunity. Such elements are microvesicles (MV) and exosome granules (EG), which for years have been confused with each other because of their similarity and imprecise nomenclature. Today, however, it is known, that these structures differ in their phenotypes and functions. MV are structures released by the morphotic elements of blood, thrombocytes, erythrocytes, monocytes, granulocytes, lymphocytes and vascular endothelium cells, and they play a role in blood clotting, adhesion, fibrinolysis and angiogenesis, as well as in inflammation and apoptosis. EG, on the other hand, belong to RNA granules, which protect genetic material in cells and are also involved in inflammation, immunity, autoimmune disorders, and cancer.
Metalloproteases (metalloproteinases, MMP) digest extracellular matrix proteins. They have zinc ions (Zn²⁺) in their active site. They are synthesized within cells as proenzymes, to be subsequently activated in the extracellular environment. MMP are active in a neutral or slightly alkaline pH in the presence of Ca²⁺ ions. Cells that synthesize metalloproteases also produce metalloprotease inhibitors. Until now, 4 of MMP inhibitors as well as 28 endometalloproteases have been discovered, out of which 22 occur in humans. On the other hand, these enzymes have not been well explored in insects, in which only 2 metalloproteases were identified (Ance and ECE). Their optimal activity ranges between pH 7.0 and 9.4. MMP inhibitors control the concentration of metalloproteases in physiological conditions. They fall within two types: specific tissue MMP inhibitors and non-specific plasma MMP inhibitors. Metalloproteases and their inhibitors play an important role in both physiological and pathological processes in the organism. Metalloproteases are cell growth promotors. They inhibit/induce apoptosis, stimulate the development of healthy cells and control the activity of neoplastic cells both in people and in insects. Their activity is increased in skin and periodontal diseases, in arthritis, arteriosclerosis or in the period following myocardial infarction. In insects the activity of MMPs is also increased by environmental pollution, by the use of antibiotics and varroacides. The insect MMPs participate in digestion, biosynthesis of peptide hormones and neurotransmitters, and melanisation. They also affect the development of the reproductive system and the development of larvae and pupae, as well as prevent pathogen invasions. Worthy of special attention is the insect cuticle defensive barrier associated with MMP. Activation of metalloproteases is dependent on the physiological state of the organism, as well as on environmental pressure. Analyzing activities of metalloproteases and their inhibitors enables better monitoring of the pathological conditions in both insects and mammals.
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