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Acquired Encephalopathies
Published in Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw, Hankey's Clinical Neurology, 2020
Herman Sullivan, Muhammad U. Farooq
The exact etiology and pathogenesis of HsE are not clear. Antithyroid antibodies are found in all patients, but their role in the pathogenesis of HsE is still uncertain. These include: Thyroperoxidase antibodies.Thyroglobulin antibodies.Thyrotropin receptor antibodies.Alpha-enolase.
Modulation of Tumor Matrix by Components of the Plasminogen-Plasmin System
Published in Róza Ádány, Tumor Matrix Biology, 2017
Native human plasminogen is a glycoprotein of about 92 kDa synthesized in the liver, and is present in plasma and extracellular fluids at a concentration of 1 to 2 μM with a biologic half-life of 2.2 d.7–10 Its structure has been defined to contain 791 amino acids, 24 disulfide bonds, and 5 kringles (triple-looped structures with three disulfide bonds).9–10 The amino-terminal is occupied by glutamic acid, hence the designate Glu-plasminogen is given to the native form. Proteolytic degradation by plasmin may occur with cleavage at Lys-77 and Lys-78, resulting in the formation of Lys-plasminogen.11 The Lys-Pg has different conformational characteristics, increasing its affinity to fibrin, enhancing its activation into plasmin, and having a shorter half-life of 0.8 d. This Lys form probably has little physiologic role in fibrinolysis, but may be important in pathologic and pericellular proteolysis. Degradation by elastase may occur at the Val-442 and VA1-443 peptide bonds resulting in a Val-form designated as mini-plasminogen.10 It too has an enhanced rate of activation into a mini-plasmin, which is more resistant than plasmin to inhibition by α2-antiplasmin. There are five lysine-binding sites in the kringle-structures of Pg which are of significance in its binding to fibrin, α2-antiplasmin, thrombospondin, and to specific lysine-binding sites on cell surfaces.12 cDNA cloning showed gene residues in chromosome 6 at q26–q27, and spans 52.5 kb with 19 exons separated by 18 introns.13 Polymorphism and point mutation may result in various forms of dysplasminogenemias.14 There are many Pg-binding sites on the cell surface, ranging from 0.37 to 49 × 105 sites/cell for circulating blood cells and from 141 to 310 × 105 sites/cell for noncirculating adherent cells, with a Kd of approximately 0.3 to 3.8 μM. When stimulated, the binding sites can exceed 107 sites/cell. Multiple components are involved in cell surface Pg binding, and a single specific plasminogen receptor has not yet been identified. Among the binding components are gangliosides, mediated through lysine-binding sites; and cell-surface peptides with carboxyl-terminal lysyl residues such as alpha-enolase. Such binding has been observed on monocytes and is inhibited by lysine and lysine analogues such as epsilon aminocaproic acid and tranexemic acid.
Acute post-streptococcal glomerulonephritis: analysis of the pathogenesis
Published in International Reviews of Immunology, 2021
Jesús Mosquera, Adriana Pedreañez
Streptococcal enolase (SE) is a novel 45-kDa protein with strong plasmin (ogen) binding activity from the surface of most streptococcal groups and serotypes and involved in tissue invasion processes. Biochemically is an alpha-enolase, a key glycolytic enzyme and its plasmin (ogen) binding activity is greater than other streptococcal proteins capable of binding to plasmin (ogen) [110]. This protein can be secreted in vivo, since secreted alpha-enolase in vitro [111] and in vivo in patients with invasive candidiasis [112] have been reported. Rheumatic fever and APSGN are both non-suppurative complications of streptococcal infection [3]. The cross-reactivity between anti-streptococcal enolase antibodies with the enolase expressed on the surface of hematopoietic cells have been reported to have a role in the pathogenesis of acute rheumatic fever [113]. In addition, it has been demonstrated circulating and glomerular anti α-enolase auto-antibodies in idiopathic human membranous glomerulonephritis and lupus nephritis [114] in these cases glomerular alpha enolase acts as a planted antigen [115]. Therefore, the capacity to bind to plasmin(ogen) and to elicit immune response suggest an important role of this protein in APSGN and streptococcal autoimmune diseases [110]. The possible presence of several streptococcal proteins in the kidney during streptococcal infection, opens up the possibility that different effects from those proteins takes place in renal tissue and the modulation between them (Figure 3).
Immunoseroproteomic profiling in autoantibody to ENO1 as potential biomarker in immunodiagnosis of osteosarcoma by serological proteome analysis (SERPA) approach
Published in OncoImmunology, 2021
Jitian Li, Liping Dai, Manyu Huang, Yan Ma, Zhiping Guo, Xiao Wang, Wuyin Li, Jian-Ying Zhang
Eleven representative sera were selected from OS patients with common strong immunoreactivity in the 1-D Western blotting. The NC membranes were incubated with these 11 representative OS sera and a pool of 5 NHS used as control. Images of immunoblots of Two-dimensional gel electrophoresis (2-DE) analysis gels exposed on films were overlaid and digitally matched with images of the corresponding Coomassie Blue-stained reference 2-DE gels (Figure 3). Protein spots in stained 2-DE gels corresponding to the immunoreactive spots were then processed for MALDI-TOF/TOF MS analysis and the resulting MS/MS spectra were analyzed by the MASCOT search engine using the NCBI and UniProt database. Interestingly, alpha-enolase (ENO1) was identified as the top hit from the 47kD spot recognized by 10 of the 11 selected OS sera and without immunoreaction with NHS pool. SERPA analysis of other immunoreactive spots with other region recognized by these 11 reactive OS sera revealed additional candidate TAAs involved in different molecule functions. As shown in Table 2, a total of 20 proteins from U2-OS and Saos-2 cell lines hits were identified from the analysis of 2-DE spots recognized by these 11 highly reactive OS sera compared with the NHS pool. Moreover, five of them (ENO1, GAPDH, TPI1, DENND4A, and TUBA1C) were identified successfully from both of two cell lines. The 20 identified proteins were predicted to be involved in 48 different biological processes, to possibly have 10 kinds of molecular functions, and to involve eight categories of cellular components (Figure S1).
Periodontal sources of citrullinated antigens and TLR agonists related to RA
Published in Autoimmunity, 2018
Ljubomir Vitkov, Matthias Hannig, Bernd Minnich, Martin Herrmann
DNA of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, and Treponema denticola is reportedly present in the synovial fluid from patients with and without RA. The copy number of DNA from P. gingivalis is higher in patients with RA when compared with controls [78]. P. gingivalis bacteria have been shown to induce NET formation [89], a source of citrullinated autoantigens. Anti-P. gingivalis antibody concentrations were significantly increased in individuals at risk for the development of RA as compared to controls and were detectable years before the onset of clinical symptoms of RA. This supports an aetiological role for P. gingivalis for the development of RA [89]. Molecular mimicry with autoantigens is a further possible mechanism driving the development of autoimmunity by P. gingivalis-derived antigens. Antibodies to the RA-specific citrullinated alpha-enolase peptide 1 have been observed in 37–62%, 3%, and 2% of the sera obtained from patients with RA, disease controls, and healthy controls, respectively. Thus, antibodies to citrullinated alpha-enolase peptide 1 are specific for rheumatoid arthritis and cross-react with P. gingivalis enolase [90]. Furthermore, A. actinomycetemcomitans can induce the formation of ROS-independent citrullinated NET driven by the pore-forming leukotoxin A [91].