Multiple Sclerosis: Enzymatic Cross Site-Specific Hydrolysis of H1 Histone by IgGs against H1, H2A, H2B, H3, H4 Histones, and Myelin Basic Protein.

Georgy A Nevinsky,Svetlana V Baranova,Valentina N Buneva,Pavel S Dmitrenok

doi:10.3390/biom11081140

Abstract

Histones play a key role in chromatin remodeling and gene transcription. Further, free histones in the blood act as damage-associated molecules. Administration of histones to animals results in systemic inflammatory and toxic effects. Myelin basic protein is the principal constituent element of the myelin-proteolipid sheath of axons. Abzymes (antibodies with catalytic activities) are the original features of some autoimmune diseases. In this study, electrophoretically homogeneous IgGs against H1, H2A, H2B, H3, and H4 histones and myelin basic protein (MBP) were isolated from the blood sera of multiple sclerosis (MS) patients by several affinity chromatographies. Using MALDI mass spectrometry, the sites of H1 histone cleavage by IgGs against H1, H2A, H2B, H3, H4, and MBP were determined. It was shown that IgGs against H1 split H1 at 12 sites, while the number of cleavage sites by abzymes against other histones was lower: H2A (9), H2B (7), H3 (3), and H4 (3). The minimum rate of H1 hydrolysis was observed for antibodies against H3 and H4. A high rate of hydrolysis and the maximum number of H1 hydrolysis sites (17) were found for antibodies against MBP. Only a few sites of H1 hydrolysis by anti-H1 antibodies coincided with those for IgGs against H2A, H2B, H3, H4, and MBP. Thus, the polyreactivity of complexation and the enzymatic cross-activity of antibodies against H1, four other histones, and MBP have first been shown. Since histones act as damage molecules, abzymes against histones and MBP can play a negative role in the pathogenesis of MS and probably other different diseases as well.

Highlights

We used previously described electrophoretically homogeneous polyclonal IgGs from the sera of 15 multiple sclerosis (MS) patients isolated by sequential chromatography of the serum proteins, first on Protein G-Sepharose in conditions allowing for the removal of nonspecifically bound proteins [31,32,33,34]
To analyze the “average” site-specific hydrolysis of H1 histone by IgGs against five histones (H1–H4), we prepared a mixture of equal amounts of 15 IgGs (IgGmix ), which demonstrated high activities in the splitting of H1 histone and myelin basic protein (MBP)
Any possible artifacts due to traces of contaminating canonical proteases were excluded earlier [31]; the IgGmix was separated by SDS-PAGE, and its histone- and MBP-hydrolyzing activities were detected in only one protein band corresponding to IgGmix

Summary

Introduction

The spontaneous and antigen-accelerated development of autoimmune diseases (AIDs) leads to the production of auto-antibodies-abzymes (ABZs) against lipids, polysaccharides, peptides, proteins, DNAs and RNAs, and their complexes. In the blood sera of autoimmune disease patients, many different ABZs directly against various antigens mimicking transition states of chemical reactions have been found. IgGs or IgMs, and IgAs splitting DNAs, RNAs [8,9,10,11,12], oligosaccharides [13,14,15], oligopeptides, and proteins [16,17,18,19,20,21,22,23] have been found in the blood of patients with autoimmune and various viral diseases [1,2,3,4,5,6]

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