Novel Autoantibodies Related to Cell Death and DNA Repair Pathways in Systemic Lupus Erythematosus

Abstract

Systemic lupus erythematosus (SLE) is a complex autoimmune syndrome characterized by various co-existing autoantibodies (autoAbs) in patients’ blood. However, the full spectrum of autoAbs in SLE has not been comprehensively elucidated. In this study, a commercial platform bearing 9400 antigens (ProtoArray) was used to identify autoAbs that were significantly elevated in the sera of SLE patients. By comparing the autoAb profiles of SLE patients with those of healthy controls, we identified 437 IgG and 1213 IgM autoAbs that the expression levels were significantly increased in SLE (P < 0.05). Use of the ProtoArray platform uncovered over 300 novel autoAbs targeting a broad range of nuclear, cytoplasmic, and membrane antigens. Molecular interaction network analysis revealed that the antigens targeted by the autoAbs were most significantly enriched in cell death, cell cycle, and DNA repair pathways. A group of autoAbs associated with cell apoptosis and DNA repair function, including those targeting APEX1, AURKA, POLB, AGO1, HMGB1, IFIT5, MAPKAPK3, PADI4, RGS3, SRP19, UBE2S, and VRK1, were further validated by ELISA and Western blot in a larger cohort. In addition, the levels of autoAbs against APEX1, HMGB1, VRK1, AURKA, PADI4, and SRP19 were positively correlated with the level of anti-dsDNA in SLE patients. Comprehensive autoAb screening has identified novel autoAbs, which may shed light on potential pathogenic pathways leading to lupus.

Omega-3 fatty acid intake suppresses induction of diverse autoantibody repertoire by crystalline silica in lupus-prone mice

“…Multiplexed protein arrays have been validated extensively to be comparable with ELISA for antibody detection [8,39,108,109]. This approach has been proven to be a Figure 11.…”

“…The AAg array employed here contains a group of 122 selected autoantigens shown to be targets of autoreactive antibodies in lupus and other autoimmune diseases [41,42,[110][111][112][113]. This specific platform has been used by other investigators for profiling a wide spectrum of autoantibodies in patients with lupus, as well as in genetically modified autoimmune mouse models [8,108,[114][115][116][117]. A key feature that made protein array particularly advantageous for this specific murine preclinical investigation is the low volume (<100 ml) required for the BALF and plasma samples.…”

“…Based on a review of published investigations, Yaniv et al [6] reported that at least 180 diverse AAbs have been associated with patients with lupus, 102 of which correlate with disease activity. Recently, a high-density protein array screening revealed over 300 novel AAbs related to cell death and DNA repair pathways in human lupus [8]. Targeted AAgs were associated with several tissue and cellular compartments, including the nucleus, cytoplasm, cell membrane, phospholipid-associated proteins, blood cells, endothelial cells, nervous system antigens, plasma proteins, and matrix proteins.…”

DNA Damage Response and Oxidative Stress in Systemic Autoimmunity

“…Another research group studied by immunoprecipitation the correlation between anti-Ku antibodies in SLE sera and antibodies against four different DNA repair proteins (DNA-PK, PARP, Mre11, and Werner protein) and found that more than 50% of anti-Ku positive sera contained at least one out of four autoantibodies, providing further evidence that abnormal DSB repair influences the development of certain autoimmune diseases [125]. Recently, Luo and colleagues, using a commercial human protein microarray platform bearing over 9400 antigens, compared the autoantibody profile of SLE patients with those of healthy controls and found novel autoantibodies that were related to DNA repair pathways and apoptosis [126]. Interestingly, they observed that the levels of autoantibodies against Apurinic/Apyrimidinic Endodeoxyribonuclease 1 (APEX1), High mobility group box 1 (HMGB1), vaccinia-related kinase 1 (VRK1), Aurora-A kinase (AURKA), peptidyl arginine deiminase 4 (PADI4), and signal recognition particle 19 (SRP19) (all involved in the DDR/R pathways) were positively correlated with the level of anti-dsDNA in SLE patients, suggesting that these autoantibodies may play a critical role in the pathogenesis of SLE.…”

Applications of Protein Microarrays in Biomarker Discovery for Autoimmune Diseases

“…The idea was later commercialized as ProtoArray® Human Protein Microarrays by Invitrogen™ (now under Thermo Fisher Scientific) and contained over 9,000 full-length human proteins. To date, the ProtoArray® Human Protein Microarrays have been widely used in identification of new biomarkers for many AIDs, including neuromyelitis optica ( 8 ), RA ( 42 ), primary Sjögren's syndrome ( 60 ), chronic renal disease ( 82 ), inflammatory bowel disease ( 52 ), type 1 diabetes ( 55 ), Meniere's Disease ( 63 ), autoimmune polyendocrine syndrome type 1 ( 65 ), acute disseminated encephalomyelitis ( 64 ), ulcerative colitis ( 83 ), SLE ( 33 ), and ankylosing spondylitis ( 9 ). In addition to the ProtoArray® Human Protein Microarrays, several new commercial proteome arrays have become available with additional protein probes using different expression systems.…”