Serum Clusterin and Complement Factor H May Be Biomarkers Differentiate Primary Sjögren's Syndrome With and Without Neuromyelitis Optica Spectrum Disorder

Inter-tissue differences in oxidative stress susceptibility reveal a less stable endothelial barrier in the brain than in the retina

Oxidative stress can impair the endothelial barrier and thereby enable autoantibody migration in Neuromyelitis optica spectrum disorder (NMOSD). Tissue-specific vulnerability to autoantibody-mediated damage could be explained by a differential, tissue-dependent endothelial susceptibility to oxidative stress. In this study, we aim to investigate the barrier integrity and complement profiles of brain and retinal endothelial cells under oxygen-induced oxidative stress to address the question of whether the pathomechanism of NMOSD preferentially affects the brain or the retina. Primary human brain microvascular endothelial cells (HBMEC) and primary human retinal endothelial cells (HREC) were cultivated at different cell densities (2.5*104 to 2*105 cells/cm2) for real-time cell analysis. Both cell types were exposed to 100, 500 and 2500 μM H2O2. Immunostaining (CD31, VE-cadherin, ZO-1) and Western blot, as well as complement protein secretion using multiplex ELISA were performed. HBMEC and HREC cell growth phases were cell type-specific. While HBMEC cell growth could be categorized into an initial peak, proliferation phase, plateau phase, and barrier breakdown phase, HREC showed no proliferation phase, but entered the plateau phase immediately after an initial peak. The plateau phase was 7 h shorter in HREC. Both cell types displayed a short-term, dose-dependent adaptive response to H2O2. Remarkably, at 100 μM H2O2, the transcellular resistance of HBMEC exceeded that of untreated cells. 500 μM H2O2 exerted a more disruptive effect on the HBMEC transcellular resistance than on HREC. Both cell types secreted complement factors H (FH) and I (FI), with FH secretion remaining stable after 2 h, but FI secretion decreasing at higher H2O2 concentrations. The observed differences in resistance to oxidative stress between primary brain and retinal endothelial cells may have implications for further studies of NMOSD and other autoimmune diseases affecting the eye and brain. These findings may open novel perspectives for the understanding and treatment of such diseases.

Protein-A immunoadsorption combined with immunosuppressive treatment in refractory primary Sjögren's syndrome coexisting with NMOSD: a case report and literature review

The treatment of primary Sjögren's syndrome (pSS) coexisting with neuromyelitis optica spectrum disorder (NMOSD) using protein-A immunoadsorption combined with immunosuppressive therapy has rarely been reported. Herein, we present the case of a 35-year-old female diagnosed with pSS concomitant with NMOSD (pSS-NMOSD) who demonstrated a positive response to protein-A immunoadsorption after failing to respond to therapy comprising high-dose intravenous methylprednisolone (IVMP) and intravenous immunoglobulin (IVIG). Within one week of receiving three sessions of immunoadsorption combined with immunosuppressive treatment, the patient's clinical symptoms (blurred vision, paraparesis, and dysfunctional proprioception) significantly improved. Additionally, a rapid decrease in the circulating levels of Aquaporin-4 immunoglobulin G antibodies (AQP4-IgG), immunoglobulin (Ig) A, IgG, IgM, erythrocyte sedimentation rate (ESR), and rheumatoid factor (RF) were observed. Magnetic resonance imaging (MRI) further revealed a significant reduction in the lesions associated with longitudinal extensive transverse myelitis. During the follow-up period, prednisolone was gradually tapered to a maintenance dose of 5-10 mg/day, whereas mycophenolate mofetil (MMF) was maintained at 1.0-1.5 g/day. The patient's condition has remained stable for four years, with no signs of recurrence or progression observed on imaging examination. Therefore, this case suggests that protein A immunoadsorption may represent a potentially effective therapeutic option for patients with pSS-NMOSD who are refractory to conventional treatments.

Application of omics in Sjögren's syndrome

OBJECTIVE

The pathogenesis, diagnosis, and treatment of Sjögren's syndrome (SS) face many challenges, and there is an urgent need to develop new technologies to improve our understanding of SS.

METHODS

By searching the literature published domestically and internationally in the past 20 years, this artical reviewed the research of various omics techniques in SS.

RESULTS

Omics technology provided valuable insights into the pathogenesis, early diagnosis, condition and efficacy evaluation of SS. It is helpful to reveal the pathogenesis of the disease and explore new treatment schemes, which will open a new era for the study of SS.

CONCLUSION

At present, omics research has made some gratifying achievements, but there are still many uncertainties. Therefore, in the future, we should improve research techniques, standardize the collection of samples, and adopt a combination of multi-omics techniques to jointly study the pathogenesis of SS and provide new schemes for its treatment.

Sjögren's syndrome: novel insights from proteomics and miRNA expression analysis

Introduction

Sjögren's syndrome (SS) is a systemic autoimmune disease, which affects the exocrine glands leading to glandular dysfunction and, particularly, symptoms of oral and ocular dryness. The aetiology of SS remains unclear, and the disease lacks distinctive clinical features. The current diagnostic work-up is complex, invasive and often time-consuming. Thus, there is an emerging need for identifying disease-specific and, ideally, non-invasive immunological and molecular biomarkers that can simplify the diagnostic process, allow stratification of patients, and assist in monitoring the disease course and outcome of therapeutic intervention in SS.

Methods

This systematic review addresses the use of proteomics and miRNA-expression profile analyses in this regard.

Results and discussion

Out of 272 papers that were identified and 108 reviewed, a total of 42 papers on proteomics and 23 papers on miRNA analyses in saliva, blood and salivary gland tissue were included in this review. Overall, the proteomic and miRNA studies revealed considerable variations with regard to candidate biomarker proteins and miRNAs, most likely due to variation in sample size, processing and analytical methods, but also reflecting the complexity of SS and patient heterogeneity. However, interesting novel knowledge has emerged and further validation is needed to confirm their potential role as biomarkers in SS.

Lysine Demethylase 1B Promotes Tear Secretion Disorder in Sjogren's Syndrome by Regulating the PAX6/CLU Axis

The impacts of lysine demethylase 1B (KDM1B) have been probed in multiple diseases, but the effects of KDM1B on SS remained obscure. The study aimed to unravel the efficiency of KDM1B on SS progression via the paired box 6 (PAX6)/clusterin (CLU) axis. NOD^{B10. H2b} mice were selected to establish the SS model. KDM1B, Pax6, and CLU expression in SS mice was assessed. Adeno-associated viruses carrying KDM1B, Pax6, and CLU were injected into the SS mice to detect tear secretion, epithelium corneal fluorescein staining scores, and levels of specific markers of lacrimal gland epithelial cells, neurotransmitter receptors that induce secretion from the lacrimal gland, and genes encoding normal tear components. The relation among KDM1B, Pax6, and CLU was examined. The rescue experiments were conducted for verifying the interaction among KDM1B, Pax6, and CLU. KDM1B expression was elevated, while Pax6 and CLU levels were decreased in the lacrimal gland tissues of SS mouse models. KDM1B decrement and Pax6 augmentation improved tear secretion, reduced corneal fluorescein staining score, decreased levels of specific markers of lacrimal gland epithelial cells, and increased levels of neurotransmitter receptors that induce secretion from the lacrimal gland and genes encoding normal tear components. KDM1D suppressed Pax6 expression by mediating H3K4me2 demethylation. Pax6 promoted the expression of CLU at the transcriptional level by binding to the CLU promoter. Silencing of Pax6 or CLU could reverse the effects of KDM1B reduction on improving the tear secretion disorder of SS mice. Silencing KDM1B mitigates the tear secretion disorder of SS mice via modulating the Pax6/CLU axis.

DIGE Analysis of Clinical Specimens

Two-dimensional difference gel electrophoresis (2D-DIGE) is an elegant gel electrophoretic analytical tool for comparative protein assessment. It is based on two-dimensional gel electrophoresis (2D-GE) separation of fluorescently labeled protein extracts. The tagging procedures are designed to not interfere with the chemical properties of proteins with respect to their pI and electrophoretic mobility, once a proper labeling protocol is followed. The use of an internal pooled standard makes 2D-DIGE a highly accurate quantitative method enabling multiple protein samples to be separated on the same two-dimensional gel. Technical limitations of this technique (i.e., underrating of low abundant, high molecular mass and integral membrane proteins) are counterbalanced by the incomparable separation power which allows proteoforms and unknown PTM (posttranslational modification) identification. Moreover, the image matching and cross-gel statistical analysis generates robust quantitative results making data validation by independent technologies successful.

The Therapeutic and Prognostic Role of Clusterin in Diverse Musculoskeletal Diseases: A Mini Review

This mini-review aims to introduce the association between Secretory clusterin/apolipoprotein J (sCLU) and diverse musculoskeletal diseases. A comprehensive review of the literature was performed to identify basic science and clinical studies, which implied the therapeutic and prognostic role of sCLU in diverse musculoskeletal diseases. sCLU is a multifunctional glycoprotein that is ubiquitously expressed in various tissues and is implicated in many pathophysiological processes. Dysregulated expression of sCLU had been reported to be assocaited with proliferative or apoptotic molecular processes and inflammatory responses, which participated in many pathophysiological processes such as degenerative musculoskeletal diseases including ischemic osteonecrosis, osteoarthritis (OA) and degenerative cervical myelopathy (spinal cord injury), neoplastic musculoskeletal diseases, inflammatory and autoimmune musculoskeletal diseases including Rheumatoid arthritis (RA), joint damage induced by Brucella abortus, Sjogren's syndrome, idiopathic inflammatory myopathies, muscle glucose metabolism, insulin sensitivity and traumatic musculoskeletal diseases. Recent findings of sCLU in these musculoskeletal diseases provides insights on the therapeutic and prognostic role of sCLU in these musculoskeletal diseases. sCLU may serve as a promising therapeutic target for ischemic osteonecrosis, OA and spinal cord injury as well as a potential prognostic biomarker for OA and RA. Moreover, sCLU could act as a prognostic biomarker for osteosarcoma (OS) and a promising therapeutic target for OS resistance. Although many studies support the potential therapeutic and prognostic role of sCLU in some inflammatory and autoimmune-mediated musculoskeletal diseases, more future researches are needed to explore the molecular pathogenic mechanism mediated by sCLU implied in these musculoskeletal diseases.

The therapeutic and prognostic role of clusterin in diverse musculoskeletal diseases: a mini review

This mini-review aims to introduce the association between Secretory clusterin/apolipoprotein J (sCLU) and diverse musculoskeletal diseases. A comprehensive review of the literature was performed to identify basic science and clinical studies, which implied the therapeutic and prognostic role of sCLU in diverse musculoskeletal diseases. sCLU is a multifunctional glycoprotein that is ubiquitously expressed in various tissues and is implicated in many pathophysiological processes. Dysregulated expression of sCLU had been reported to be assocaited with proliferative or apoptotic molecular processes and inflammatory responses, which participated in many pathophysiological processes such as degenerative musculoskeletal diseases including ischemic osteonecrosis, osteoarthritis (OA) and degenerative cervical myelopathy (spinal cord injury), neoplastic musculoskeletal diseases, inflammatory and autoimmune musculoskeletal diseases including Rheumatoid arthritis (RA), joint damage induced by Brucella abortus, Sjogren's syndrome, idiopathic inflammatory myopathies, muscle glucose metabolism, insulin sensitivity and traumatic musculoskeletal diseases. Recent findings of sCLU in these musculoskeletal diseases provides insights on the therapeutic and prognostic role of sCLU in these musculoskeletal diseases. sCLU may serve as a promising therapeutic target for ischemic osteonecrosis, OA and spinal cord injury as well as a potential prognostic biomarker for OA and RA. Moreover, sCLU could act as a prognostic biomarker for osteosarcoma (OS) and a promising therapeutic target for OS resistance. Although many studies support the potential therapeutic and prognostic role of sCLU in some inflammatory and autoimmune-mediated musculoskeletal diseases, more future researches are needed to explore the molecular pathogenic mechanism mediated by sCLU implied in these musculoskeletal diseases.

Visual Evoked Potentials as Potential Biomarkers of Visual Function in Patients with Primary Sjögren's Syndrome

Visual evoked potentials (VEP) are changes in potentials that arise in the central nervous system. In the interpretation of the VEP test results, it is assumed that the elongation of the latency time is caused by the demyelination of the nerve fibers, and the axon damage is responsible for the decrease in the amplitude. The observed VEP deviations are not specific for specific diseases, but indicate disturbances in visual conductivity. VEP may play a diagnostic role in the early detection of visual involvement. The aim of the study was the functioning of visual pathway assessment on the basis of visual evoked potentials (VEP) examination, in patients with primary Sjögren’s Syndrome (pSS), without focal symptoms of central nervous system disorder. The effect of disease activity, as assessed by clinical parameters and antibody levels (anti-Ro52, SSA, and SSB), on the central nervous system was also evaluated. Thirty-two consecutive patient with pSS (31 females, 1 male) were included in the study. VEP was performed at baseline, and after 6 (T6) years. Their results were compared longitudinally between the baseline and T6, depending on the duration of the disease and treatment. The immunological activity of pSS was also analyzed. The group of patients showed a significant prolongation of the P100 implicit time (105.5 ± 5.1 vs. 100.6 ± 3.9; p = 0.000) and a significant higher the P100-N145 amplitude (12.3 ± 4.1 vs. 9.4 ± 3.0; p = 0.000). Abnormalities in electrophysiological parameters of VEP at baseline correlated with presentation of anti-Ro52 antibodies and aching joints. At baseline, the P100 implicit time was shorter for the patients with pSS than for those at T6 (105.50 ± 5.1 vs. 109.37 ± 5.67; p = 0.002). pSS patients without CNS involvement presented with dysfunction of visual pathway, as revealed by VEP abnormalities. Relationships were found between VEP parameters and with present of anti-Ro52 antibodies and aching joints. VEP may be a useful method for assessment and monitoring of subclinical visual deficit in the course of pSS.

Proteomic profiling of saliva reveals association of complement system with primary Sjögren's syndrome

INTRODUCTION

To compare the saliva proteomes of experimental Sjögren's syndrome (ESS) model mice and healthy controls to identify potential diagnostic biomarkers for primary Sjögren's syndrome (pSS).

METHODS

Proteins were extracted from the saliva of three ESS and three normal control mice using the data-independent acquisition technique. R language was used to identify the differentially expressed proteins (DEPs). Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses were performed to functionally annotate the DEPs. The protein-protein interaction (PPI) network was constructed and the core proteins were identified with the STRING website and Cytoscape software. The concentrations of Serpin family G member 1 (SERPING1), C3, complement factor H (CFH), fibrinogen alpha (FGA), and fibrinogen gamma (FGG) in saliva were determined by ELISA.

RESULTS

A total of 1722 DEPs were identified in the saliva of the ESS mice relative to the controls, of which 50 showed significantly different expression levels between the two groups. SERPING1, C3, CFH, FGA, and FGG were significantly downregulated, and keratin 4 (Krt4) and transglutaminase 3 (TGM3) were upregulated in the saliva of ESS mice. The PPI network showed that SERPING1, C3, FGG, FGA, TGM3, and hemopexin (HPX) were the core proteins. ELISA results showed that the expression of C3, CFH, FGA, and SERPING1 were significantly downregulated in the saliva of ESS mice. However, the expression of FGG was a little downregulated but with no significant difference. SERPING1, FGG, and FGA may downregulate the complement C3 by inhibiting immune complement system, thereby promoting pSS progression.

CONCLUSIONS

The salivary proteome of ESS mice was markedly different from that of healthy controls, suggesting that salivary proteomics is a promising noninvasive diagnostic tool for pSS. SERPING1, C3, CFH, FGA, and FGG are potential biomarkers of pSS.