chondroitin-sulfates and Amyloidosis

Approximately 10% of patients with peripheral neuropathy of otherwise unknown etiology have an associated monoclonal gammopathy. Both the neuropathies and the monoclonal gammopathies in these patients are heterogeneous, but several distinct clinical syndromes that may respond to specific therapies can be recognized. It is important to recognize these syndromes because monoclonal gammopathies also occur in 1% of the normal adult population, and in some cases, monoclonal gammopathies are coincidental and unrelated to the neuropathy. In patients with IgM monoclonal gammopathies, IgM M proteins frequently have autoantibody activity and are implicated in the pathogenesis of the neuropathy. IgM M proteins that bind to myelin-associated glycoprotein (MAG) have been shown to cause demyelinating peripheral neuropathy; anti-GM1 antibody activity is associated with predominantly motor neuropathy, and anti-sulfatide or chondroitin sulfate antibodies are associated with sensory neuropathy. The IgM monoclonal gammopathies may be malignant or nonmalignant, and polyclonal antibodies with the same specificities are associated with similar clinical presentations in the absence of monoclonal gammopathy. IgG or IgA monoclonal gammopathies are associated with neuropathy in patients with osteosclerotic myeloma or the POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy myeloma, and skin changes). Amyloidosis or cryoglobulinemic neuropathies can occur with either IgM or IgG and IgA monoclonal gammopathies. Therapeutic intervention depends on the specific clinical syndrome but is generally directed at removing the autoantibodies, reducing the number of monoclonal B cells, and interfering with the effector mechanisms.

Topics: Adult; Aged; Amyloidosis; Antibody Specificity; Antineoplastic Agents; Autoantibodies; Autoantigens; Autoimmune Diseases; Chondroitin Sulfates; Gangliosides; Humans; Immunoglobulin A; Immunoglobulin G; Immunoglobulin M; Immunoglobulins, Intravenous; Middle Aged; Myelin-Associated Glycoprotein; Paraneoplastic Syndromes; Paraproteinemias; Paraproteins; Peripheral Nervous System Diseases; Plasmapheresis; Sulfoglycosphingolipids

Amyloid light chain (AL) amyloidosis is a protein misfolding disease where immunoglobulin light chains sample partially folded states that lead to misfolding and amyloid formation, resulting in organ dysfunction and death. In vivo, amyloid deposits are found in the extracellular space and involve a variety of accessory molecules, such as glycosaminoglycans, one of the main components of the extracellular matrix. Glycosaminoglycans are a group of negatively charged heteropolysaccharides composed of repeating disaccharide units. In this study, we investigated the effect of glycosaminoglycans on the kinetics of amyloid fibril formation of three AL cardiac amyloidosis light chains. These proteins have similar thermodynamic stability but exhibit different kinetics of fibril formation. We also studied single restorative and reciprocal mutants and wild type germ line control protein. We found that the type of glycosaminoglycan has a different effect on the kinetics of fibril formation, and this effect seems to be associated with the natural propensity of each AL protein to form fibrils. Heparan sulfate accelerated AL-12, AL-09, κI Y87H, and AL-103 H92D fibril formation; delayed fibril formation for AL-103; and did not promote any fibril formation for AL-12 R65S, AL-103 delP95aIns, or κI O18/O8. Chondroitin sulfate A, on the other hand, showed a strong fibril formation inhibition for all proteins. We propose that heparan sulfate facilitates the formation of transient amyloidogenic conformations of AL light chains, thereby promoting amyloid formation, whereas chondroitin sulfate A kinetically traps partially unfolded intermediates, and further fibril elongation into fibrils is inhibited, resulting in formation/accumulation of oligomeric/protofibrillar aggregates.

Topics: Amino Acid Substitution; Amyloidogenic Proteins; Amyloidosis; Chondroitin Sulfates; Heparitin Sulfate; Humans; Immunoglobulin kappa-Chains; Mutation, Missense; Protein Aggregation, Pathological

Dialysis-related amyloidosis (DRA) is a complication of hemodialysis where beta2-microglobulin (beta2m) forms plaques mainly in cartilaginous tissues. The tissue-specific deposition, along with a known intransigence of pure beta2m to form fibrils in vitro at neutral pH in the absence of preformed fibrillar seeds, suggests a role for factors within cartilage in enhancing amyloid formation from this protein. To identify these factors, we determined the ability of a derivative lacking the N-terminal six amino acids found in ex vivo beta2m amyloid deposits to form amyloid fibrils at pH 7.4 in the absence of fibrillar seeds. We show that the addition of the glycosaminoglycans (GAGs) chrondroitin-4 or 6-sulfate to fibril growth assays results in the spontaneous generation of amyloid-like fibrils. By contrast, no fibrils are observed over the same time course in the presence of hyaluronic acid, a nonsulfated GAG that is abundant in cartilaginous joints. Based on the observation that hyaluronic acid has no effect on fibril stability, while chrondroitin-6-sulfate decreases the rate of fibril disassembly, we propose that the latter GAG enhances amyloid formation by stabilizing the rare fibrils that form spontaneously. This leads to the accumulation of beta2m in fibrillar deposits. Our data rationalize the joint-specific deposition of beta2m amyloid in DRA, suggesting mechanisms by which amyloid formation may be promoted.

Topics: Amyloid; Amyloidosis; beta 2-Microglobulin; Cartilage; Chondroitin Sulfates; Glycosaminoglycans; Humans; Hyaluronic Acid; Protein Conformation

Light-chain amyloidosis (AL) is characterized by immunoglobulin light-chain fragments aggregating into amyloid fibrils that deposit extracellularly in vital organs such as the kidney, the heart, and the liver, resulting in tissue degeneration and organ failure, leading to death. Cardiac involvement is found in 50% of AL patients and presents the most severe cases with a life expectancy of less than a year after diagnosis. In this study, we have characterized the variable domain of a cardiac AL patient light chain called AL-09. AL-09 folds as a beta-sheet and is capable of forming amyloid fibrils both in the presence of sodium sulfate and in self-seeded reactions under physiological conditions. Glycosaminoglycans such as dermatan sulfate and heparin promote amyloid formation of self-seeded AL-09 reactions, while the glycosaminoglycan chondroitin sulfate A stabilized oligomeric intermediates and did not elongate the preformed fibrils (nucleus) present in the reaction. Finally, the histological dye Congo red, known to bind to the cross beta-sheet structure of amyloid fibrils, inhibits AL-09 amyloid fibril formation in the presence of sodium sulfate and in self-seeded reactions. This paper provides insight into the impact of different reagents on light-chain stability, structure, amyloid fibril formation, and inhibition.

Topics: Amyloid; Amyloidosis; Chondroitin Sulfates; Congo Red; Dermatan Sulfate; Glycosaminoglycans; Heart Diseases; Heparin; Humans; Immunoglobulin Light Chains; Molecular Structure; Sulfates

A constant finding in beta (2)-microglobulin (beta 2m) amyloidosis is an increase in tissue heparan sulfate (HS) and chondroitin sulfate (CS) proteoglycans (PGs) at sites of amyloid deposits. However, the binding characteristics of PGs with beta 2m have not been elucidated yet.. Using affinity retardation chromatography, beta 2m- and glycosaminoglycan (GAG)-anchored columns, an affinity between beta 2m and GAGs was analyzed. Five peptides which spanned the entire beta 2m amino acid sequence were prepared, and an affinity between these peptides and heparin (HP) was examined. Furthermore, the specific binding of biotinylated beta 2m peptide for AA amyloid deposits via GAGs was examined on tissue sections.. Using beta 2m-anchored column, HP showed the smallest dissociation constant (K(d)), i.e. the strongest affinity, among the GAGs examined. At 0.4 M NaCl, the K(d)s of beta 2m relative to BSA-anchored columns for HP, HS, CS-A, CS-B, and CS-C were 94, 620, 130, 660 and 190 microM, respectively. Using GAG-anchored columns, at 0.15 M NaCl, pH 7.4, beta 2m also showed an affinity for HP, with the K(d) relative to a reference column being 370 microM. Under the latter conditions, no beta 2m affinity for CSA was demonstrated. Among the five peptides, peptide-1, which is composed of residues 1-24, showed the highest affinity for HP, the K(d) being 190 microM. Peptides analogous to peptide-1, in which each basic amino acid was individually replaced by alanine, showed a remarkable decrease in affinity for HP. The specific binding of biotinylated beta 2m peptide for AA amyloid deposits via HS and CS was confirmed in situ by pretreatment with heparitinase and chondroitinase ABC.. The present data indicate that HP/HS is effective in the binding of the beta 2m monomer, and the anatomic localization of beta 2m amyloid precursor protein.

Topics: Amino Acid Sequence; Amyloidosis; beta 2-Microglobulin; Chondroitin Sulfates; Chromatography, Affinity; Heparitin Sulfate; Humans; Kidney; Kidney Failure, Chronic; Molecular Sequence Data; Peptide Fragments; Protein Binding; Renal Dialysis

Patterns of amyloid distribution and extracellular matrix changes in the heart and gastrointestinal tract were compared among beta 2-microglobulin (B2M), AA (secondary), and AL (primary and multiple myeloma-associated) amyloidosis cases. B2M amyloid was found to be mainly distributed in the small arterioles, venules, endocardium and muscularis propria of these organs, the deposits characteristically forming subendothelial nodular lesions in the vessels. A marked increase of chondroitin sulfate (CS) was consistently detected in B2M amyloid. Heparan sulfate (HS) also showed an increase in amyloid deposits, but with less reactivity than CS in the small arterioles or venules. Basement membrane structures stained positively for laminin and collagen type IV were replaced by negative amyloid deposits. In the AL cases, the muscularis propria of the gastrointestinal tract was involved in amyloid deposits, as seen for the B2M type, but the vascular amyloid deposits were localized in the media and adventitia of larger vessels. Immunoreactivity for HS was more intense than that for CS, and no increase in laminin or collagen type IV was observed. In the AA cases, amyloid deposits were distributed in the capillaries, small arterioles, interstitium of the myocardium and mucosa. Immunoreactivity for laminin and collagen type IV was marked, and more intense than that for HS and CS. Although the existence of a direct relationship between increase in extracellular matrix material and amyloidogenesis remains to be proven, the observed variation in extracellular matrix changes in the background of each type of amyloidosis may indicate different binding sites of the amyloid precursor proteins, resulting in the specific histological features and distribution.

Topics: Adult; Aged; Aged, 80 and over; Amyloid; Amyloid beta-Protein Precursor; Amyloidosis; beta 2-Microglobulin; Cardiomyopathies; Chondroitin Sulfates; Digestive System; Extracellular Matrix; Female; Gastrointestinal Diseases; Heparitin Sulfate; Humans; Male; Middle Aged; Myocardium; Renal Dialysis

Fibrils of hemodialysis-associated beta 2-microglobulin amyloid were examined by high resolution electron microscopy and immunohistochemical labeling. The amyloid containing tissues obtained through autopsy were prepared for thin section observations. In contrast to other forms of amyloid, the most conspicuous feature of these fibrils were their curved conformations. The fibril core showed ultrastructural and immunohistochemical features in common with the core of connective tissue microfibrils and of previously observed fibrils of experimental murine AA amyloidosis and familial amyloid polyneuropathy (FAP). The core was wrapped in a layer of 3 nm wide ribbon-like "double tracked" structures identified as chondroitin sulfate proteoglycan (CSPG) with immunogold labeling as well as from the results of previous in vitro experiments. Finally, the outer surface of the fibril was associated with a loose assembly of 1 nm wide filaments immunohistochemically identified as beta 2-microglobulin. This is similar to the manner in which AA protein and transthyretin filaments are associated with their respective fibrils. The results of this study provide an additional example for the concept that amyloid fibrils in general are microfibril-like structures externally associated with amyloid protein filaments. An unusual feature of the fibrils of hemodialysis-associated amyloid, however, is the presence of a peripheral layer composed of CSPG rather than of heparan sulfate proteoglycan (HSPG) as in the case of the other two amyloids above. These chondroitin sulfate chains in the outer CSPG layer may be less effective in providing rigidity to the fibril core, thus allowing for the curved conformations of beta 2-microglobulin amyloid fibrils.

Topics: Aged; Amyloid; Amyloidosis; beta 2-Microglobulin; Chondroitin Sulfates; Humans; Immunohistochemistry; Male; Microscopy, Immunoelectron; Renal Dialysis

Topics: Amyloidosis; Animals; beta 2-Microglobulin; Chondroitin Sulfates; Glycosaminoglycans; Heparitin Sulfate; Humans; Mice; Rats; Renal Dialysis

Topics: Amyloidosis; Animals; Caseins; Chondroitin Sulfates; Chondroitinases and Chondroitin Lyases; Chromatography, DEAE-Cellulose; Disaccharides; Electrophoresis, Cellulose Acetate; Glycosaminoglycans; Liver Diseases; Male; Mice; Mice, Inbred BALB C; Splenic Diseases; Uronic Acids