There are many evidences that nonimmunologic factors contribute to pathogenesis of primary glomerulonephritides. Proteolytic enzymes plays important role in glomerular protein turn-over and their altered activities may have influence on glomerular function. The purpose of this paper was to review the role of proteolytic enzymes in initiation and progression of idiopathic glomerular diseases.
IL-6 issynthetized by various types of cells and has multiple biological functions.In the kidney, IL-6 synthesized by mesangial cells and acts as an autocrine growth factor.Il-6 was demonstrated in the glomerular measangium and in teh urine of patients with proliferative glomerulonephritis, suggesting that it has an important role in the pathogenesis of renal glomerular diseases.
After several decades of research into the macrophage migration inhibitory factor (MIF), its diverse actions in the immune system are yet to be fully revealed. What has become clear is that MIF plays an important role in both innate and adaptive immunity. However, while several pathways mediating the function of MIF in the immune system have been established, its role in pathogenic states such as autoimmune diseases has remained unresolved. MIF has been implicated in different autoimmune diseases, including rheumatoid arthritis, glomerulonephritis, and multiple sclerosis, but knowledge about the underlying cellular and molecular mechanisms is just emerging. However, overall it appears that the inhibition of its proinflammatory action is likely to be a successful new therapeutic strategy for some autoimmune diseases, possibly by reducing the need for steroids. As more aspects of the role of this cytokine in the pathogenesis of autoimmune diseases are elucidated, better strategies to target it therapeutically can be expected.
Anti-glomerular basement membrane (GBM) glomerulonephritis, which was among the earliest recognized human autoimmune diseases, is characterized by the presence of anti- -GBM antibody. It has been a prototypical example of autoantibody-mediated autoimmune disease. However, decades of research on this disease, based either on clinical observations or experimental models, have revealed that T cell-mediated cellular immunity may potentially be a more important mediator of glomerulonephritis. We have made several breakthroughs in understanding the T cell-mediated mechanism causing this disease in a rat model based on Goodpasture's antigen, non-collagen domain 1 of ?3 chain of type IV collagen (Col4alpha3NC1). We demonstrated that anti-GBM glomerulonephritis was induced by either passive transfer of Col4alpah3NC1-specific T cells or active immunization with the nephritogenic T cell epitope of Col4alpha3NC1. Immunization with the T cell epitope also triggered production of anti-GBM antibodies to diversified GBM antigens. Thus, a single nephritogenic T cell epitope alone is sufficient to induce the clinical spectrum of anti-GBM glomerulonephritis, including proteinuria, glomerular injury, and anti-GBM antibody. A possible T cell-mediated mechanism for causing human anti-GBM disease is proposed.
Complement is important to host defense and the regulation of inflammation. The liver is overwhelmingly the major source of circulating complement. However, many other organs are capable of synthesizing some or all of the complement components in a regulated tissue-specific manner. There is increasing evidence that this locally generated complement is biologically active and exerts powerful effects within the local environment. We review the role of local complement synthesis within different organs and speculate on its implication for immune and metabolic functions.
The glomerular basement membrane (GBM) is a kind of net that remains in a state of dynamic equilibrium. Heparan sulfate proteoglycans (HSPGs) are among its most important components. There are much data indicating the significance of these proteoglycans in protecting proteins such as albumins from penetrating to the urine, although some new data indicate that loss of proteoglycans does not always lead to proteinuria. Heparanase is an enzyme which cleaves 1,4 d-glucuronic bonds in sugar groups of HSPGs. Thus it is supposed that heparanase may have an important role in the pathogenesis of proteinuria. Increased heparanase expression and activity in the course of many glomerular diseases was observed. The most widely documented is the significance of heparanase in the pathogenesis of diabetic nephropathy. Moreover, heparanase acts as a signaling molecule and may influence the concentrations of active growth factors in the GBM. It is being investigated whether heparanase inhibition may cause decreased proteinuria. The heparanase inhibitor PI-88 (phosphomannopentaose sulfate) was effective as an antiproteinuric drug in an experimental model of membranous nephropathy. Nevertheless, this drug is burdened by some toxicity, so further investigations should be considered.
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