Ly9 (CD229) Antibody Targeting Depletes Marginal Zone and Germinal Center B Cells in Lymphoid Tissues and Reduces Salivary Gland Inflammation in a Mouse Model of Sjögren's Syndrome

Subpopulation dynamics of T and B lymphocytes in Sjögren's syndrome: implications for disease activity and treatment

Sjögren's syndrome (SS) is an autoimmune disorder primarily affecting the body's exocrine glands, particularly the salivary and lacrimal glands, which lead to severe symptoms of dry eyes and mouth. The pathogenesis of SS involves the production of autoantibodies by activated immune cells, and secretion of multiple cytokines, which collectively lead to tissue damage and functional impairment. In SS, the Immune interaction among T and B cells is particularly significant. Lymphocytic infiltration in the salivary glands is predominantly composed of CD4+ T cells, whose activation cause the death of glandular epithelial cells and subsequent tissue destruction. The excessive activity of T cells contributes significantly to the disease mechanism, with helper T cells (CD4+) differentiating into various subgroups including Th1/Th2, Th17, as well as Treg, each contributing to the pathological process through distinct cytokine secretion. In patients with SS, B cells are excessively activated, leading to substantial production of autoantibodies. These antibodies can attack self-tissues, especially the lacrimal and salivary glands, causing inflammation and tissue damage. Changes in B cell subpopulations in SS patients, such as increases in plasmablasts and plasma cells, correlate positively with serum autoantibody levels and disease progression. Therapies targeting T cells and B cells are extensively researched with the aim of alleviating symptoms and improving the quality of life for patients. Understanding how these cells promote disease development through various mechanisms, and further identifying novel T and B cell subgroups with functional characterization, will facilitate the development of more effective strategies to treat SS.

Study of LY9 as a potential biomarker for prognosis and prediction of immunotherapy efficacy in lung adenocarcinoma

Background

Lymphocyte antigen 9 (LY9) participates in the development of several tumors and diseases but has not been reported yet in lung adenocarcinoma (LUAD).

Methods

First, we analyzed the expression and prognostic value of LY9 in pan-cancer, including LUAD. Additionally, we conducted a correlation analysis of LY9 expression in LUAD with immune cell infiltration using the TIMER database and the CIBERSORT algorithm, and with immune checkpoints using the GEPIA database. Also, we constructed a potential ceRNA network for LY9. Furthermore, we explored LY9-related pathways by Gene Set Enrichment Analysis (GSEA). Finally, validation of differential expression at the mRNA level was obtained from the GEO database. We collected LUAD tissues for Quantitative Real-time PCR (qRT-PCR) to verify the expression of LY9, CD8, and CD4 and calculated the correlation between them. We also conducted immunohistochemistry (IHC) to verify the protein expression of LY9.

Results

Results showed that LY9 was highly expressed in various tumors, including LUAD. Besides, patients with high LY9 expression presented longer overall survival (OS) and more multiple lymphocyte infiltrations. The expression of LY9 in LUAD strongly and positively correlates with multiple immune cell infiltration and immune checkpoints. The functional enrichment analysis indicated that LY9 was involved in multiple immune-related pathways and non-small cell lung cancer. Moreover, a ceRNA regulatory network of LINC00943-hsa-miR-141-3p-LY9 might be involved. Finally, GSE68465 dataset confirmed differential expression of LY9 mRNA levels in LUAD and the qRT-PCR results verified LY9 had a strong and positive correlation with CD4 and CD8 T cells. Unfortunately, IHC did not detect the expression of LY9 protein level in tumor tissues and WB experiments validated the protein expression of LY9 in the OCI-AML-2 cell line.

Conclusions

Therefore, we hypothesized that LY9 could serve as a potential, novel prognostic biomarker for LUAD and could predict immunotherapy efficacy at the mRNA level.

SLAMF3 promotes Th17 differentiation and is reversed by iguratimod through JAK1/STAT3 pathway in primary Sjögren's syndrome

OBJECTIVE

The signaling lymphocytic activation molecule family of receptors (SLAMF) is involved in the activation of T cells and plays important roles in the pathogenesis of autoimmune diseases. The purpose of this study is to observe the expression of SLAMF3 on CD4 + T cells and its effect on the differentiation of T helper 17 (Th17) in primary Sjögren's syndrome (pSS). Furthermore, we found iguratimod (IGU) could effectively reverse the aberrant Th17 differentiation through JAK1/STAT3 signaling.

METHODS

Peripheral blood mononuclear cells from 40 pSS and 40 healthy control subjects were enrolled for analysis of expression of SLAMF3 on CD4 + T and Th17 cells by flow cytometry. Serum IL-17 and SLAMF3 were detected by ELISA assay. Labial biopsies from 20 pSS patients and 20 non-pSS controls were performed immunohistochemical for staining expression of CD4, IL-17, and SLAMF3. Under the priming conditions with anti-CD3/CD28 or CD3/SLAMF3 antibodies on CD4 + T cells extracted from pSS and controls, the proportion of Th17 cells in CD4 + T cells and the amount of soluble IL-17A were assessed by flow cytometry and ELISA. Furthermore, RNA sequencing was performed for the transcriptomics study. Additionally, RNA level of RORγt and IL-17A and the protein level of RORγt, p-JAK1 and p-STAT3, were detected by real-time PCR and western blot.

RESULTS

The expression levels of SLAMF3 on CD4 + T and Th17 cells in the peripheral blood and salivary glands in pSS patients were significantly elevated than that in control groups. The serum IL-17A and SLAMF3 in pSS patients were much higher compared with the control group. Although co-stimulation of CD3/SLAMF3 could promote CD4 + T cells differentiate into Th17 cells both in pSS and controls, the CD4 + T cells from pSS have a more sensitive response in Th17 differentiation with the SLAMF3 stimulation. Transcriptomics results showed the CD3/SLAMF3 stimulation caused the activation of Th17 signaling and JAK1/STAT3 pathway. Quantitative PCR and western blotting confirmed the IGU (iguratimod), which is a safe clinical drug in treatment of autoimmune diseases, effectively reversed the increased Th17 proportion, the expression levels of RORγt, pJAK1, and pSTAT3 caused by CD3/SLAMF3 stimulation.

CONCLUSION

SLAMF3 upregulates Th17 cell differentiation of CD4 + T cells and IL-17A secretion through enriching RORγt and activating the transcriptomics participating in the pathogenesis of primary Sjögren's syndrome. IGU could inhibit the process through this therapeutic target in pSS.

Extracellular vesicle-encapsulated miR-10a-5p derived from MDSCs restrains germinal center B cells in experimental Sjögren's syndrome

Primary Sjögren's syndrome (pSS) is a progressive systemic autoimmune disease characterized by chronic inflammation of the exocrine glands, resulting in damage to the salivary and lacrimal glands. Our group and other researchers have reported that myeloid-derived suppressor cell-derived extracellular vesicles (MDSC-EVs) could attenuate the progression of autoimmune disease by impairing T-cell function. However, the effect of MDSC-EVs on B-cell function and the underlying mechanism remains largely unknown. In this study, we found that MDSC-EVs significantly attenuated the progression of experimental Sjögren's syndrome (ESS). Moreover, treatment with MDSC-EVs via intravenous injection markedly reduced the percentage of germinal center (GC) B cells in ESS mice. In vitro, MDSC-EVs could directly suppress the generation of GC B cells and the expression of B cell lymphoma 6 (Bcl-6) in B cells under GC B-cell-polarizing conditions. Mechanistically, miR-10a-5p carried by MDSC-EVs regulated the differentiation of GC B cells by targeting Bcl-6, and inhibition of miR-10a-5p in MDSC-EVs significantly reversed the effect of MDSC-EVs involved in alleviating the development of ESS. Taken together, our findings demonstrated that miR-10a-5p carried by MDSC-EVs inhibited the generation of B cells by targeting Bcl-6 and eventually alleviated the progression of ESS, which may provide novel therapeutic targets for the treatment of pSS.

Therapeutic Potential of Anti-Interferon α Vaccination on SjS-Related Features in the MRL/lpr Autoimmune Mouse Model

Sjögren’s syndrome (SjS) is a frequent systemic autoimmune disease responsible for a major decrease in patients’ quality of life, potentially leading to life-threatening conditions while facing an unmet therapeutic need. Hence, we assessed the immunogenicity, efficacy, and tolerance of IFN-Kinoid (IFN-K), an anti-IFNα vaccination strategy, in a well-known mouse model of systemic autoimmunity with SjS-like features: MRL/MpJ-Faslpr/lpr (MRL/lpr) mice. Two cohorts (with ISA51 or SWE01 as adjuvants) of 26 female MRL/lpr were divided in parallel groups, “controls” (not treated, PBS and Keyhole Limpet Hemocyanin [KLH] groups) or “IFN-K” and followed up for 122 days. Eight-week-old mice received intra-muscular injections (days 0, 7, 28, 56 and 84) of PBS, KLH or IFN-K, emulsified in the appropriate adjuvant, and blood samples were serially collected. At sacrifice, surviving mice were euthanized and their organs were harvested for histopathological analysis (focus score in salivary/lacrimal glands) and IFN signature evaluation. SjS-like features were monitored. IFN-K induced a disease-modifying polyclonal anti-IFNα antibody response in all treated mice with high IFNα neutralization capacities, type 1 IFN signature’s reduction and disease features’ (ocular and oral sicca syndrome, neuropathy, focus score, glandular production of BAFF) improvement, as reflected by the decrease in Murine Sjögren’s Syndrome Disease Activity Index (MuSSDAI) modelled on EULAR Sjögren’s Syndrome Disease Activity Index (ESSDAI). No adverse effects were observed. We herein report on the strong efficacy of an innovative anti-IFNα vaccination strategy in a mouse model of SjS, paving the way for further clinical development (a phase IIb trial has just been completed in systemic lupus erythematosus with promising results).

Autoimmune B Cell Repertoire in a Mouse Model of Sjögren's Syndrome

In genetically prone individuals, chronic immune activation may lead to expansion of autoreactive lymphocyte clones that can induce organ damage developing autoimmune disorders. Sjögren’s Syndrome (SjS) is a systemic chronic autoimmune disease that primarily affects exocrine glands. Despite the accumulated evidences of profound B-cell alterations of humoral immunity, the repertoire and development of B-cell autoreactivity in SjS remains to be determined. We hypothesize that SjS mice will have an increased frequency of self-reactive B cells with a progressive evolution to antigen-driven oligoclonality. Here, we study the B cell repertoire of NOD.H-2^h4 mice, a mouse model of spontaneous autoimmunity mimicking SjS without developing diabetes. A library of 168 hybridomas from NOD.H-2^h4 mice and 186 C57BL/6J splenocytes at different ages was created. The presence of mono or polyreactive autoantibodies to several antigens was evaluated by ELISA, and their staining patterns and cellular reactivity were tested by IFA and FACS. We observed a higher frequency of autoreactivity among B-cell clones from NOD.H-2^h4 mice as compared to wild-type mice. The presence of polyreactive and autoreactive IgG clones increased with mice age. Strikingly, all anti-Ro52 autoantibodies were polyreactive. No loss of polyreactivity was observed upon antibody class switching to IgG. There was a progression to oligoclonality in IgG B cells with mice aging. Our results indicate that in the NOD.H-2^h4 mouse model of SjS, IgG+ B cells are mainly polyreactive and might expand following an unknown antigen-driven positive selection process.

Machine learning analysis of gene expression profile reveals a novel diagnostic signature for osteoporosis

Background

Osteoporosis (OP) is increasingly prevalent with the aging of the world population. It is urgent to identify efficient diagnostic signatures for the clinical application.

Method

We downloaded the mRNA profile of 90 peripheral blood samples with or without OP from GEO database (Number: GSE152073). Weighted gene co-expression network analysis (WGCNA) was used to reveal the correlation among genes in all samples. GO term and KEGG pathway enrichment analysis was performed via the clusterProfiler R package. STRING database was applied to screen the interaction pairs among proteins. Protein–protein interaction (PPI) network was visualized based on Cytoscape, and the key genes were screened using the cytoHubba plug-in. The diagnostic model based on these key genes was constructed, and 5-fold cross validation method was applied to evaluate its reliability.

Results

A gene module consisted of 176 genes predicted to be associated with the occurrence of OP was identified. A total of 16 significantly enriched GO terms and 1 significantly enriched KEGG pathway were obtained based on the 176 genes. The top 50 key genes in the PPI network were identified. Then 22 genes were screened based on stepwise regression analysis from the 50 key genes. Of which, 9 genes were further screened out by multivariate regression analysis with the significant threshold of P value < 0.01. The diagnostic model was established based on the optimal 9 key genes, which efficiently separated the normal samples and OP samples.

Conclusion

A diagnostic model established based on nine key genes could reliably separate OP patients from healthy subjects, which provided novel lightings on the diagnostic research of OP.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02329-1.

Marginal zone B cells: From housekeeping function to autoimmunity?

Marginal zone (MZ) B cells comprise a subset of innate-like B cells found predominantly in the spleen, but also in lymph nodes and blood. Their principal functions are participation in quick responses to blood-borne pathogens and secretion of natural antibodies. The latter is important for housekeeping functions such as clearance of apoptotic cell debris. MZ B cells have B cell receptors with low poly-/self-reactivity, but they are not pathogenic at steady state. However, if simultaneously stimulated with self-antigen and pathogen- and/or damage-associated molecular patterns (PAMPs/DAMPs), MZ B cells may participate in the initial steps towards breakage of immunological tolerance. This review summarizes what is known about the role of MZ B cells in autoimmunity, both in mouse models and human disease. We cover factors important for shaping the MZ B cell compartment, how the functional properties of MZ B cells may contribute to breaking tolerance, and how MZ B cells are being regulated.

Contributions of Major Cell Populations to Sjögren's Syndrome

Sjögren’s syndrome (SS) is a female dominated autoimmune disease characterized by lymphocytic infiltration into salivary and lacrimal glands and subsequent exocrine glandular dysfunction. SS also may exhibit a broad array of extraglandular manifestations including an elevated incidence of non-Hodgkin’s B cell lymphoma. The etiology of SS remains poorly understood, yet progress has been made in identifying progressive stages of disease using preclinical mouse models. The roles played by immune cell subtypes within these stages of disease are becoming increasingly well understood, though significant gaps in knowledge still remain. There is evidence for distinct involvement from both innate and adaptive immune cells, where cells of the innate immune system establish a proinflammatory environment characterized by a type I interferon (IFN) signature that facilitates propagation of the disease by further activating T and B cell subsets to generate autoantibodies and participate in glandular destruction. This review will discuss the evidence for participation in disease pathogenesis by various classes of immune cells and glandular epithelial cells based upon data from both preclinical mouse models and human patients. Further examination of the contributions of glandular and immune cell subtypes to SS will be necessary to identify additional therapeutic targets that may lead to better management of the disease.