Anti-centromere antibodies target centromere-kinetochore macrocomplex: a comprehensive autoantigen profiling.

OBJECTIVES: Anti-centromere antibodies (ACAs) are detected in patients with various autoimmune diseases such as Sjögren's syndrome (SS), systemic sclerosis (SSc) and primary biliary cholangitis (PBC). However, the targeted antigens of ACAs are not fully elucidated despite the accumulating understanding of the molecular structure of the centromere. The aim of this study was to comprehensively reveal the autoantigenicity of centromere proteins. METHODS: A centromere antigen library including 16 principal subcomplexes composed of 41 centromere proteins was constructed. Centromere protein/complex binding beads were used to detect serum ACAs in patients with SS, SSc and PBC. ACA-secreting cells in salivary glands obtained from patients with SS were detected with green fluorescent protein-fusion centromere antigens and semiquantified with confocal microscopy. RESULTS: A total of 241 individuals with SS, SSc or PBC and healthy controls were recruited for serum ACA profiling. A broad spectrum of serum autoantibodies was observed, and some of them had comparative frequency as anti-CENP-B antibody, which is the known major ACA. The prevalence of each antibody was shared across the three diseases. Immunostaining of SS salivary glands showed the accumulation of antibody-secreting cells (ASCs) specific for kinetochore, which is a part of the centromere, whereas little reactivity against CENP-B was seen. CONCLUSIONS: We demonstrated that serum autoantibodies target the centromere-kinetochore macrocomplex in patients with SS, SSc and PBC. The specificity of ASCs in SS salivary glands suggests kinetochore complex-driven autoantibody selection, providing insight into the underlying mechanism of ACA acquisition.

Antigen-driven selection of antibodies against SSA, SSB and the centromere 'complex', including a novel antigen, MIS12 complex, in human salivary glands.

OBJECTIVES: Recent evidences have revealed that anti-SSA/SSB antibodies, the major autoantibodies in Sjögren's syndrome (SS), are produced in salivary glands. This study aims to clarify overall of autoantibody production at lesion site, including anti-centromere antibody (ACA)-positive SS. METHODS: Antibodies of antibody-secreting cells in human salivary glands were produced as recombinant antibodies. The reactivity of these antibodies and their revertants were investigated by ELISA and newly developed antigen-binding beads assay, which can detect conformational epitopes. The target of uncharacterised antibodies was identified by immunoprecipitation and mass spectrometry. Autoantibody-secreting cells in salivary gland tissue were identified by immunohistochemistry using green fluorescent protein-autoantigen fusion proteins. RESULTS: A total of 256 lesion antibodies were generated, and 69 autoantibodies including 24 ACAs were identified among them. Beads assay could detect more autoantibodies than ELISA, suggesting autoantibodies target to antigens with native conformation. After somatic hypermutations were reverted, autoantibodies drastically decreased antigen reactivity. We showed that MIS12 complex, a novel target of ACA, and CENP-C are major targets of ACA produced in salivary glands by examining cloned antibodies and immunohistochemistry, whereas few anti-CENP-B antibodies were detected. The target profiling of serum ACA from 269 patients with SS, systemic sclerosis (SSc), primary biliary cirrhosis (PBC) and healthy controls revealed that ACA-positive patients have antibodies against various sites of centromere complex regardless of disease. CONCLUSION: We showed direct evidences of antigen-driven maturation of anti-SSA/SSB antibody and ACA in SS lesion. ACA recognises centromere 'complex' rather than individual protein, and this feature is common among patients with SS, SSc and PBC.

Multiomic disease signatures converge to cytotoxic CD8 T cells in primary Sjögren's syndrome.

OBJECTIVES: Multiomics study was conducted to elucidate the crucial molecular mechanisms of primary Sjögren's syndrome (SS) pathology. METHODS: We generated multiple data set from well-defined patients with SS, which includes whole-blood transcriptomes, serum proteomes and peripheral immunophenotyping. Based on our newly generated data, we performed an extensive bioinformatic investigation. RESULTS: Our integrative analysis identified SS gene signatures (SGS) dysregulated in widespread omics layers, including epigenomes, mRNAs and proteins. SGS predominantly involved the interferon signature and ADAMs substrates. Besides, SGS was significantly overlapped with SS-causing genes indicated by a genome-wide association study and expression trait loci analyses. Combining the molecular signatures with immunophenotypic profiles revealed that cytotoxic CD8 -T cells- were associated with SGS. Further, we observed the activation of SGS in cytotoxic CD8 T cells isolated from patients with SS. CONCLUSIONS: Our multiomics investigation identified gene signatures deeply associated with SS pathology and showed the involvement of cytotoxic CD8 T cells. These integrative relations across multiple layers will facilitate our understanding of SS at the system level.

Value of labial salivary gland histopathology for diagnosis of Sjögren's syndrome in patients with anti-centromere antibody positivity.

AIM/INTRODUCTION: Although anti-centromere antibody (ACA)+ Sjögren's syndrome (SS) is considered a subtype of SS, it was not included in the recent American College of Rheumatology/ European League Against Rheumatism (ACR/EULAR) SS classification criteria. ACA+ patients without anti-SS-A/Ro antibodies require salivary gland histopathology to fulfill the ACR/EULAR criteria for diagnosis of SS. We reviewed salivary gland histology among ACA+ patients referred for the diagnosis of SS using the ACR/EULAR and Japanese criteria which does not require biopsy. METHOD: Data from 147 ACA+ patients with dry eyes and/or mouth who visited our department were retrospectively analyzed. Clinical, immunological, and histological data were collected and statistically analyzed. RESULT: Sixty-five patients (44%) had undergone labial salivary gland biopsy. The frequency of dry mouth was higher in ACA+ patients who had undergone labial salivary gland biopsy than in those who had not (P = .046), while there were no differences in biopsy rates between patients with and without sclerodactyly (P = .51). According to the current ACR/EULAR classification criteria, Greenspan grade of 3 or 4 for labial salivary gland histopathology is required in patients without anti-SS-A/Ro antibody for the diagnosis of SS. Four patients with Greenspan grades <3 and anti-SS-A/Ro antibody met the criteria for SS. In 54 patients in which the ACR/EULAR criteria were met, 53 patients were diagnosed with SS using the Japanese criteria. CONCLUSION: In ACA+/anti-SS-A/Ro- antibody patients, agreement between ACR/EULAR and Japanese criteria sets was excellent. For easily classifying ACA+ patients as SS cases, salivary gland biopsy should be performed in ACA+ patients with dry symptoms to identify ACA+ patients.

Characterization of Long-Term Cultured Murine Submandibular Gland Epithelial Cells.

PURPOSE: Human and rat salivary gland cell lines derived from tumors or genetic modification are currently available for research. Here, we attempted to culture and characterize long-term cultured cells spontaneously derived from wild type murine submandibular glands (SGs). METHODS: SGs were removed from 3-week-old C57B/6J female mice and dissociated by collagenase type 1 and hyaluronidase digestion. Isolated SG epithelial cells were cultured in low calcium, serum-free growth media in the presence of cholera toxin (CT) during early passages. Single-cell colonies were isolated by limiting dilution culture after 25 passages. Early- and late-stage cell cultures were characterized for keratin 14, keratin 18, α-smooth muscle actin, and p63 by immunostaining and quantitative real-time PCR analysis. RESULTS: SG epithelial cells cultured in optimized media maintained their proliferative ability and morphology for over 80 passages. Long-term cultured cells expressed keratin 14, keratin 18, and p63, indicative of an epithelial phenotype. CONCLUSIONS: Epithelial cells originating from wild type murine SGs could be cultured for longer periods of time and remain phenotypically similar to ductal basal epithelium.

Abdominal breathing increases tear secretion in healthy women.

PURPOSE: To determine the relationship between abdominal breathing and tear meniscus volume in healthy women, we investigated the change in tear meniscus volume in two groups: normal breathing and abdominal breathing. METHODS: We used a crossover experimental model and examined 20 healthy women aged 20-54 years (mean ± SD, 32.7 ± 11.1 years). The participants were randomly assigned to one of two groups. During the first visit, the normal breathing group was subjected to normal breathing for 3 min, whereas the abdominal breathing group was subjected to abdominal breathing (4-second inhalation and 6-second exhalation) for 3 min. During the second visit, the protocols were swapped between the two groups. We estimated the R wave to R wave (R-R) interval, tear meniscus volume, salivary amylase activity, pulse, and blood pressure before and immediately after, 15 min after, and 30 min after completion of the breathing activity. RESULTS: After abdominal breathing, compared to that before breathing, the tear meniscus volume increased significantly 15 min after breathing (P<.01). Furthermore, systolic blood pressure showed a significant decrease immediately after abdominal breathing (P<0.05). No significant difference was found in the test parameters in the normal breathing group. CONCLUSION: Abdominal breathing for 3 minutes increases the tear meniscus volume in healthy women. Consequently, abdominal breathing may be considered in the treatment of dry eye disease.