Synthesis of Phospholipid-Protein Conjugates as New Antigens for Autoimmune Antibodies

Abstract

Copper(I)-catalyzed azide-alkyne cycloaddition, or CuAAC click chemistry, is an efficient method for bioconjugation aiming at chemical and biological applications. Herein, we demonstrate how the CuAAC method can provide novel phospholipid-protein conjugates with a high potential for the diagnostics and therapy of autoimmune conditions. In doing this, we, for the first time, covalently bind via 1,2,3-triazole linker biologically complementary molecules, namely phosphoethanol amine with human β2-glycoprotein I and prothrombin. The resulting phospholipid-protein conjugates show high binding affinity and specificity for the autoimmune antibodies against autoimmune complexes. Thus, the development of this work might become a milestone in further diagnostics and therapy of autoimmune diseases that involve the production of autoantibodies against the aforementioned phospholipids and proteins, such as antiphospholipid syndrome and systemic lupus erythematosus.

Synthetic oligonucleotide antigens modified with locked nucleic acids detect disease specific antibodies

“…The reaction was stopped with 1 M H 2 SO 4 (50 μL/well). Plates were analyzed using a Magellan TECAN microplate reader and measuring absorbance at 450 nm 41 .…”

Novel Phospholipid-Protein Conjugates Allow Improved Detection of Antibodies in Patients with Autoimmune Diseases

“…Applying lipids and proteins as separate antigens is due to the previously unachievable synthesis of synthetic conjugates with well-defined structure and purity. Indeed, lipidation of proteins is a challenging chemical process, which potentially can result in low yields and insufficient purity of products [ 9 ]. Recent progress in bioconjugation, including the development of copper-catalyzed azide-alkyne cycloaddition, or CuAAC click chemistry, opens up an exciting opportunity to create such reagents using synthetic biomolecules [ 11 ].…”

“…Advantages of the synthetic antigens compared to natural analogues are high chemical and biological stability, purity and well defined chemical structure of the bioconjugation products [ 11 ]. Recently, we proved high efficacy of the CuAAC approach for the synthesis of phosphoethanolamine conjugates with prothrombin and β2GPI [ 9 ]. However, attempts to attach oxidized cardiolipin 7 to same proteins resulted in low yields and low biologic activity of products ( Fig 1 , compounds 4–6 ).…”

“…However, attempts to attach oxidized cardiolipin 7 to same proteins resulted in low yields and low biologic activity of products ( Fig 1 , compounds 4–6 ). Clearly, the conditions of oxidation for cardiolipin have to be optimized in order to obtain desired antigens in high yields [ 9 ].…”

Design, Modeling and Synthesis of 1,2,3-Triazole-Linked Nucleoside-Amino Acid Conjugates as Potential Antibacterial Agents

“…In addition to facilitating bioorthogonal chemical reactions, a broad assortment of triazole derivatives readily synthesized via CuAAC have shown promising results within the field of medicinal chemistry, with certain triazoles displaying antifungal activity against several Candida species [ 3 ]. Additionally, CuAAC has made it possible for researchers to prepare novel phospholipid-protein conjugates with high binding affinity for autoimmune antibodies [ 4 ]. Recent studies have described the use of 1,2,3-triazolyl nucleosides and nucleoside analogues as chitin synthase inhibitors [ 5 ], phosphoglycosyltransferase inhibitors [ 6 ] and anticancer [ 7 , 8 , 9 ], antiviral [ 10 , 11 ] and antimicrobial agents [ 12 , 13 , 14 ].…”