Plasma vitronectin is reduced in patients with myasthenia gravis: Diagnostic and pathophysiological potential

  • Antonio Junior Lepedda Department of Biomedical Sciences, University of Sassari, Viale San Pietro, Sassari, Italy
  • Giovanni Andrea Deiana Department of Medical, Surgical and Experimental Sciences, University of Sassari, Viale San Pietro, Sassari, Italy
  • Omar Lobina Department of Biomedical Sciences, University of Sassari, Viale San Pietro, Sassari, Italy
  • Gabriele Nieddu Department of Biomedical Sciences, University of Sassari, Viale San Pietro, Sassari, Italy
  • Paola Baldinu Department of Biomedical Sciences, University of Sassari, Viale San Pietro, Sassari, Italy
  • Pierina De Muro Department of Biomedical Sciences, University of Sassari, Viale San Pietro, Sassari, Italy
  • Francesca Andreetta Diagnostic Laboratory of Neuroimmunolgy, U.O. Neurologia IV, I.R.C.C.S. Fondazione Istituto Neurologico “C. Besta”, Milano, Italy
  • Elia Sechi Department of Medical, Surgical and Experimental Sciences, University of Sassari, Viale San Pietro, Sassari, Italy
  • Giannina Arru Department of Medical, Surgical and Experimental Sciences, University of Sassari, Viale San Pietro, Sassari, Italy
  • Davide Giacomo Corda Department of Medical, Surgical and Experimental Sciences, University of Sassari, Viale San Pietro, Sassari, Italy
  • Gian Pietro Sechi Department of Medical, Surgical and Experimental Sciences, University of Sassari, Viale San Pietro, Sassari, Italy
  • Marilena Formato Department of Biomedical Sciences, University of Sassari, Viale San Pietro, Sassari, Italy
Keywords: Myasthenia gravis, autoimmunity, vitronectin, proteomics, biomarkers

Abstract

Myasthenia gravis (MG) is an autoimmune disease leading to varying degrees of skeletal muscle weakness. It is caused by specific antibodies directed against definite components in the postsynaptic membrane at the neuromuscular junction (NMJ), such as the acetylcholine receptor (AChR) and the muscle-specific kinase (MUSK) receptor. In clinical practice, MG patients may be classified into three main subgroups based on the occurrence of serum autoantibodies directed against AChR or MUSK receptor or antibody-negative. As the MG subgroups differ in terms of clinical characteristics, disease pathogenesis, prognosis, and response to therapies, they could benefit from targeted treatment as well as the detection of other possible disease biomarkers. We performed proteomics on plasma fractions enriched in low-abundance proteins to identify potential biomarkers according to different autoimmune responses. By this approach, we evidenced a significant reduction of vitronectin in MG patients compared to healthy controls, irrespective of the autoantibodies NMJ target. The obtained results were validated by mono- and two-dimensional Western blotting analysis. Vitronectin is a multifunctional glycoprotein involved in the regulation of several pathophysiological processes, including complement-dependent immune response, coagulation, fibrinolysis, pericellular proteolysis, cell attachment, and spreading. The pathophysiological significance of the reduction of plasma vitronectin in MG patients has yet to be fully elucidated. It could be related either to a possible deposition of vitronectin at NMJ to counteract the complement-mediated muscle damage at this level or to a parallel variation of this glycoprotein in the muscle extracellular matrix with secondary induced alteration in clustering of AChRs at NMJ, as it occurs with variation in concentrations of agrin, another extracellular matrix component. The clinical value of measuring plasma vitronectin has yet to be defined. According to present findings, significantly lower plasma values of this glycoprotein might be indicative of an impaired complement-dependent immune response.
Published
2019-09-11
How to Cite
LepeddaA. J., DeianaG. A., LobinaO., NiedduG., BaldinuP., De MuroP., AndreettaF., SechiE., ArruG., CordaD. G., SechiG. P., & FormatoM. (2019). Plasma vitronectin is reduced in patients with myasthenia gravis: Diagnostic and pathophysiological potential. Journal of Circulating Biomarkers, 8(1). https://doi.org/10.33393/jcb.2019.2098
Section
Original research article