Increased protease activity and changes in basic proteins and lipids in multiple sclerosis plaques.
TL;DR: These suggest, although they do not necessarily prove, that the acid proteinase which is a lysosomal enzyme(s) plays a role in MS by releasing the encephalitogen as such a polypeptide into the circulation and in this way initiating an immunological reaction.
About: This article is published in Journal of the Neurological Sciences.The article was published on 1970-08-01. It has received 100 citations till now.
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399 citations
TL;DR: The present study showed a significant elevation of the lysosomal enzyme beta-glucosaminidase in the microscopically normal white matter in MS as compared with controls, suggesting that the white matter may be rendered more susceptible to the pathogenetic process in this disease.
362 citations
TL;DR: It is proposed that the release of neutral proteases by stimulated macrophages involved in cell-mediated reactions, and its amplification by the plasminogen-plasmin system, may play a significant role in the demyelination observed in several inflammatory demyELinating diseases.
Abstract: In inflammatory demyelinating diseases such as multiple sclerosis and experimental allergic encephalomyelitis, myelin destruction occurs in the vicinity of infiltrating mononuclear cells. The observations that myelin can be altered prior to phagocytosis and in areas not contiguous with inflammatory cells suggests a common mechanism for the initial stages of demyelination. Because stimulated macrophages secrete several neutral proteases, including plasminogen activator, we have investigated the possibility that myelinolysis could be mediated directly or indirectly by these enzymes. Isolated myelin was incubated with conditioned media from cultures of thioglycollate-stimulated mouse peritoneal macrophages in the presence and absence of plasminogen. Myelin appeared to be vulnerable to attack by at least two proteolytic activities secreted by the macrophages, a plasminogen-dependent and a plasminogen-independent activity; of the major proteins in myelin, the basic protein was most susceptible. The direct myelinolytic activity of macrophage-conditioned media was abolished by EDTA, and the plasminogen-dependent hydrolysis was abolished by p-nitrophenylguanidinobenzoate, an inhibitor of plasminogen activator and plasmin. These results suggest that the plasminogen activator released by the stimulated macrophages generated plasmin which hydrolyzed basic protein in intact myelin. This interpretation was confirmed by the observation that urokinase, a plasminogen activator, in the presence of plasminogen brought about marked degradation of basic protein in myelin. We propose that the release of neutral proteases by stimulated macrophages involved in cell-mediated reactions, and its amplification by the plasminogen-plasmin system, may play a significant role in the demyelination observed in several inflammatory demyelinating diseases.
270 citations
TL;DR: Observations suggest that in MS, immunoreactivity of periaxonal MAG is altered before myelin breakdown begins, as early in degeneration, myelin sheath fragments often were more intensely stained by BP antiserum than normal sheaths; later the staining intensity decreased.
Abstract: To study the distribution of myelin-associated glycoprotein (MAG) in human nervous tissue and in multiple sclerosis (MS) lesions, we used paraffin sections and our modification of the peroxidase-antiperoxidase technique. Sections of MS lesions also were treated with antiserum to basic protein (BP) and with histological stains for axons and myelin sheaths. In tissue from normal developing central nervous system, oligodendroglia, their processes, and newly formed myelin sheaths were intensely stained by MAG antiserum. In adults, MAG was found in periaxonal regions of myelinated fibers of the central and peripheral nervous system. The most striking finding in MS lesions was the extension of decreased MAG immunostaining into white matter that appeared normal when treated with BP antiserum or luxol fast blue. In acute early MS lesions the decrease in MAG immunostaining extended far beyond the margin of acute demyelination, where the BP staining of degenerating sheaths often was increased. In chronic inactive plaques, this decrease in periaxonal MAG immunostaining was limited to relatively few fibers in a thin rim around each lesion. These observations suggest that in MS, immunoreactivity of periaxonal MAG is altered before myelin breakdown begins. Early in degeneration, myelin sheaths and their fragments often were more intensely stained by BP antiserum than normal sheaths; later the staining intensity decreased. In shadow plaques, BP antiserum stained some oligodendroglia. Their appearance and location among thinly myelinated axons suggested that these oligondendroglia were forming new sheaths around previously demyelinated axons.
237 citations
TL;DR: Because calpain degrades all major myelin proteins, the increased activity and expression of this proteinase may play a critical role in myelinolysis in autoimmune demyelinating diseases such as MS.
Abstract: In autoimmune demyelinating diseases such as multiple sclerosis (MS), the degradation of myelin proteins results in destabilization of the myelin sheath. Thus, proteases have been implicated in myelin protein degradation, and recent studies have demonstrated increased expression and activity of a calcium-activated neutral proteinase (calpain) in experimental allergic encephalomyelitis, the corresponding animal model of MS. In the present study, calpain activity and expression (at translational and transcriptional levels) were evaluated in white matter from human patients with MS and Parkinson’s and Alzheimer’s diseases and compared with that of white matter from normal controls. Western blot analysis revealed that levels of the active form of calpain and calpain-specific degradation products (fodrin) were increased by 90.1% and 52.7%, respectively, in MS plaques compared with normal white matter. Calpain translational expression was up-regulated by 462.5% in MS plaques compared with controls, although levels of the specific endogenous inhibitor, calpastatin, were not altered significantly. At the transcriptional level, no significant changes in calpain or calpastatin expression were detected by reverse transcription–PCR. Using double immunofluorescent labeling, increased calpain expression was observed in reactive astrocytes, activated T cells, and activated mononuclear phagocytes in and adjacent to demyelinating lesions. Calpain activity and translational expression were not increased significantly in white matter from patients with Parkinson’s or Alzheimer’s diseases compared with that of normal controls. Because calpain degrades all major myelin proteins, the increased activity and expression of this proteinase may play a critical role in myelinolysis in autoimmune demyelinating diseases such as MS.
169 citations
References
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Journal Article•
TL;DR: Procedures are described for measuring protein in solution or after precipitation with acids or other agents, and for the determination of as little as 0.2 gamma of protein.
289,852 citations
TL;DR: In this paper, the authors described a simplified version of the method and reported the results of a study of its application to different tissues, including the efficiency of the washing procedure in terms of the removal from tissue lipides of some non-lipide substances of special biochemical interest.
59,550 citations
TL;DR: If the highest accuracy was not required, the following manipulations simplified and speeded multiple total phosphorus determinations on the eluates from column chromatographic separations.
12,381 citations
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TL;DR: The idea of using a chromatographic adsorbent in the form of a thin layer fixed on an inert rigid support seems to have been suggested by Izmailov and Shraiber in 1938.
Abstract: The idea of using a chromatographic adsorbent in the form of a thin layer fixed on an inert rigid support seems to have been suggested by Izmailov and Shraiber in 1938. Meinhard and Hall[1] in 1949 developed this notion of an ‘open column’, and in 1951 Kirchner, Miller, and Keller[2] reported the separation of terpenes on a ‘chromatostrip’, prepared by coating a small glass strip with an adsorbent mixed with starch or plaster of Paris, which acted as a binder. The strips were handled in the same way that paper is handled in paper chromatography, and indeed the original object of the thin-layer technique was to apply the methods of paper partition chromatography to an adsorption system.
2,382 citations
707 citations