Androgens and integrins in salivary glands in Sjogren's syndrome

Impact of sex differences on the clinical presentation, pathogenesis, treatment and prognosis of Sjögren's syndrome

Sjögren's syndrome is a common chronic autoimmune disease that manifests as dry mouth, dry eyes and systemic complications. There are sex differences in the clinical manifestations between men and women, with the average age of onset being around 55 years and the majority of female patients developing the disease during the menopausal years. Understanding the impact of sex differences on SS may help in the treatment and prognosis of patients. Studies have confirmed that a number of factors are associated with the onset of SS, but the exact mechanisms are not fully understood. Sex hormones (especially oestrogens and androgens) play a very important role, and the balance of sex hormone levels in the body is crucial for maintaining homeostasis in the acinar cells of the lacrimal and salivary glands. In addition, chromosomes play a very important role in the sex differences in SS. The gut microbiota also has some influence on sex differences in SS. In this review, we focus on oestrogens and androgens, which are important in the pathogenesis of SS, and summarize the progress of non-clinical studies. Sex differences may influence differences in individualized treatment regimens and further studies are needed.

Sexual health in women with Sjogren's syndrome: A review

BACKGROUND

Rheumatic diseases, mainly affecting women, including rheumatoid arthritis, Sjogren's syndrome, systemic lupus erythematosus, etc., are chronic, inflammatory, autoimmune disorders that may involve multiple organs or systems and are closely related to sexual health, which is an important aspect of human physical and mental health. Sjogren's syndrome (SS) is the second most common rheumatic illnesses after rheumatoid arthritis with a female predominance. At present, the research on sexual health of female SS patients is still scarce and difficult to summarize.

OBJECTIVES

The objective of our study was to systematically review the literature for the influence of maternal SS on sexual health, such as sexual function, sex hormones, fertility, and pregnancy outcomes.

METHODS

We performed a comprehensive literature search based on PubMed and Web of science databases from inception to 1 November 2022. Outcomes were divided into 4 categories: sex hormones, sexual function, fertility, and pregnancy and offspring outcomes.

RESULTS

A total of 756 potentially eligible papers were retrieved. After eliminating duplicate articles and reviewing the titles and abstracts to exclude records, we read the remaining 92 articles in full for further evaluation, and selected 42 studies. Results on sex hormones, sexual function, fertility and pregnancy and offspring outcomes were reported in 13, 12, 3 and 14 SS-related articles, respectively. The levels of some sex hormones in SS patients may have undergone changes. Female patients with SS have a high prevalence of sexual dysfunction compared with controls. Most studies suggested SS had an adverse impact on maternal and fetal outcomes following pregnancy. However, there is insufficient evidence that directly indicating the fertility of SS women is diminished.

CONCLUSIONS

In summary, certain aspects of sexual health (sexual function, sex hormones and pregnancy outcomes) are impaired in SS women. Screening for sexual health problems in SS female should become an integral part of medical clinical practice. Rheumatologists should be aware of this association and collaborate with gynecologists, obstetricians, psychologists, and other experts on this issue to determine appropriate therapeutic approaches.

Deciphering potential pharmacological mechanism of Sha-Shen-Mai-Dong decoction on primary Sjogren's syndrome

Background

Sha-Shen-Mai-Dong decoction (SSMD) is a classical prescription widely used in primary Sjogren’s Syndrome (pSS) therapy. This study aims to explore the potential pharmacological mechanism of SSMD on pSS.

Methods

Active components of SSMD were obtained from Traditional Chinese Medicine Integrative Database and Traditional Chinese Medicine Systems Pharmacology databases and targets of SSMD were predicted by Pharmmapper and STITCH database. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were carried out to explore the function characteristics of SSMD. The expression matrix of microarray of pSS was obtained from Gene Expression Omnibus and we obtained 162 differentially expressed genes (DEGs). Protein-protein interaction (PPI) networks were constructed to identify the hub targets. Principal component analysis (PCA) and molecular docking were conducted to further elucidate the possibility of SSMD for pSS.

Results

SSMD contained a total of 1056 active components, corresponding to 88 targets, among which peripheral myelin protein 2(PMP2), androgen receptor (AR) and glutamic acid decarboxylase 1(GAD1) are associated with multiple active components in SSMD and may be the core targets. Moreover, these targets were closely related to tissue pathological injury in SS, such as lacrimal gland, salivary gland and nervous system injury. GO and KEGG analysis showed that 88 targets enriched in REDOX process, transcriptional regulation and negative regulation of apoptosis process. Besides, SSMD may influence the cell proliferation, gene transcription through regulating Ras and cAMP-related signaling pathways. In addition, SSMD may show effects on immune regulation, such as macrophage differentiation, Toll-like receptor 4 signaling pathway and T-helper 1 in SS. Moreover, PPI network suggested that FN1, MMP-9 may be the hub targets in SSMD. Result of PCA and molecular docking analysis further determined the feasibility of SSMD in treating pSS.

Conclusion

SSMD can regulate multiple biological processes by virtue of its multiple active components, thus showing prominent advantage in the treatment of pSS. The discovery of active ingredients and targets in SSMD provides valuable resources for drug research and development for pSS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-021-03257-7.

Current State of Knowledge on Primary Sjögren's Syndrome, an Autoimmune Exocrinopathy

Primary Sjögren's syndrome (pSS) is a chronic systemic autoimmune rheumatic disease characterized by lymphoplasmacytic infiltration of the salivary and lacrimal glands, whereby sicca syndrome and/or systemic manifestations are the clinical hallmarks, associated with a particular autoantibody profile. pSS is the most frequent connective tissue disease after rheumatoid arthritis, affecting 0.3-3% of the population. Women are more prone to develop pSS than men, with a sex ratio of 9:1. Considered in the past as innocent collateral passive victims of autoimmunity, the epithelial cells of the salivary glands are now known to play an active role in the pathogenesis of the disease. The aetiology of the "autoimmune epithelitis" still remains unknown, but certainly involves genetic, environmental and hormonal factors. Later during the disease evolution, the subsequent chronic activation of B cells can lead to the development of systemic manifestations or non-Hodgkin's lymphoma. The aim of the present comprehensive review is to provide the current state of knowledge on pSS. The review addresses the clinical manifestations and complications of the disease, the diagnostic workup, the pathogenic mechanisms and the therapeutic approaches.

Effect of scopoletin on phagocytic activity of U937-derived human macrophages: Insights from transcriptomic analysis

Scopoletin is a botanical coumarin. Notably, scopoletin effect on phagocytic activity has not been addressed on transcriptomic level. Accordingly, this study investigated the effect of scopoletin on phagocytosis-linked gene transcription. Whole phagocytosis transcriptional profiling of stimulated U937-derived macrophages (SUDMs) in response to scopoletin as compared to non-treated SUDMs was studied. Regarding scopoletin effect on 92 phagocytosis-linked genes, 12 of them were significantly affected (p-value < .05). Seven genes were downregulated (CDC42, FCGR1A/FCGR1C, ITGA9, ITGB3, PLCE1, RHOD & RND3) and five were upregulated (DIRAS3, ITGA1, PIK3CA, PIK3R3 & PLCD1). Moreover, scopoletin enhanced phagocytic activity of SUDMs. The current results highlighted the potential use of scopoletin as immunity booster and as an adjuvant remedy in management of some autoimmune reactions. To the best of our knowledge, this is the first report that unravels the effect of scopoletin on phagocytosis via transcriptomic analysis.

Update on Pathogenesis of Sjogren's Syndrome

Sjogren's syndrome is a common autoimmune disease that presents with sicca symptoms and extraglandular features. Sjogren's syndrome is presumably as common as RA; yet it is poorly understood, underdiagnosed and undertreated. From the usual identity as an autoimmune exocrinopathy to its most recent designate as an autoimmune epithelitis - the journey of SS is complex. We herein review some of the most important milestones that have shed light on different aspects of pathogenesis of this enigmatic disease. This includes role of salivary gland epithelial cells, and their interaction with cells of the innate and adaptive immune system. Non-immune factors acting in concert or in parallel with immune factors may also be important. The risk genes identified so far have only weak association, nevertheless advances in genetics have enhanced understanding of disease mechanisms. Role of epigenetic and environmental role factors is also being explored. SS has also some unique features such as congenital heart block and high incidence of lymphoma; disease mechanisms accounting for these manifestations are also reviewed.

Sexual dimorphic function of IL-17 in salivary gland dysfunction of the C57BL/6.NOD-Aec1Aec2 model of Sjögren's syndrome

Interleukin (IL)-17 is one of the critical inflammatory cytokines that plays a direct role in development of Sjögren’s syndrome (SjS), a systemic autoimmune disease characterized by a progressive chronic attack against the exocrine glands. The expression levels of IL-17 are correlated with a number of essential clinical parameters such as focus score and disease duration in human patients. Significantly immunological differences of Th17 cells were detected at the onset of clinical disease in female SjS mice compared to males. To further define the role of IL-17 in SjS and elucidate its involvement in the sexual dimorphism, we examined the systemic effect of IL-17 by genetically ablating Il-17 in the C57BL/6.NOD-Aec1Aec2, spontaneous SjS murine model. The results indicate that IL-17 is a potent inflammatory molecule in the induction of chemoattractants, cytokines, and glandular apoptosis in males and females. Elimination of IL-17 reduced sialadenitis more drastically in females than males. IL-17 is highly involved in modulating Th2 cytokines and altering autoantibody profiles which has a greater impact on changing plasma cells and germinal center B cell populations in females than males. The result supports a much more important role for IL-17 and demonstrates the sexual dimorphic function of IL-17 in SjS.

Sexual dimorphism in an animal model of Sjögren's syndrome: a potential role for Th17 cells

Sjögren's syndrome is a complex autoimmune disease with an array of diverse immunological, genetic and environmental etiologies, making identification of the precise autoimmune mechanism difficult to define. One of the most distinctive aspects of Sjögren's syndrome is the high sexual dimorphism with women affected 10-20 times more than men. It is nearly impossible to study the sexual dimorphic development of Sjögren's syndrome in human patients; therefore it is pertinent to develop an appropriate animal model which resembles human disease. The data indicated that female C57BL/6.NOD-Aec1Aec2 mice developed an earlier onset of sialadenitis with a higher composition of CD3⁺ T cells and a 10-fold increase in glandular infiltration of Th17 cells at the onset of clinical disease compared to male mice. Inflammatory Th17 cells of female mice exhibited a stronger proliferation in response to disease-specific antigen than their male counterpart. At the clinical disease stage, altered autoantibody patterns can be detected in females whereas they are seldom observed in male C57BL/6.NOD-Aec1Aec2 mice. Interestingly, male C57BL/6.NOD-Aec1Aec2 mice developed an earlier loss of secretory function, despite the fact that female C57BL/6.NOD-Aec1Aec2 mice exhibited a more rapid secretory loss. This data indicates the strong sexual dimorphism in the SjS-susceptible C57BL/6.NOD-Aec1Aec2 animal model, making it an appropriate animal model to examine human disease.

Summary: Sjogren's syndrome (SjS) is the one of the most common sexual dimorphic autoimmune diseases. This study demonstrates that female C57BL/6.NOD-Aec1Aec2 mice develop earlier onset and more severe symptoms of SjS than male counterparts. Therefore, the C57BL/6.NOD-Aec1Aec2 mouse model could be an appropriate model to study sexual dimorphism in SjS.

Molecular cues for development and regeneration of salivary glands

The hypofunction of salivary glands caused by Sjögren's Syndrome or radiotherapy for head and neck cancer significantly compromises the quality of life of millions patients. Currently no curative treatment is available for the irreversible hyposalivation, whereas regenerative strategies targeting salivary stem/progenitor cells are promising. However, the success of these strategies is constrained by the lack of insights on the molecular cues of salivary gland regeneration. Recent advances in the molecular controls of salivary gland morphogenesis provided valuable clues for identifying potential regenerative cues. A complicated network of signaling molecules between epithelia, mesenchyme, endothelia, extracellular matrix and innervating nerves orchestrate the salivary gland organogenesis. Here we discuss the roles of several cross-talking intercellular signaling pathways, i.e., FGF, Wnt, Hedgehog, Eda, Notch, Chrm1/HB-EGF and Laminin/Integrin pathways, in the development of salivary glands and their potentials to promote salivary regeneration.

Dysfunction of lacrimal and salivary glands in Sjögren's syndrome: nonimmunologic injury in preinflammatory phase and mouse model

Sjögren's syndrome (SjS) is a chronic autoimmune disorder characterized by dry eyes and dry mouth due to dacryoadenitis and sialoadenitis with SS-A/Ro and/or SS-B/La autoantibodies in genetically predisposed individuals. Destruction of lacrimal and salivary glands by autoimmune reactions may lead to clinical manifestation. However, the mechanisms behind the decreased volume of secretions in tears and saliva are complex and are not fully understood. Exocrine gland dysfunction may precede autoimmunity (acquired immunity) or represent a process independent from inflammation in the pathogenesis of SjS. The preceded functional and morphologic changes of those tissues by nonimmunologic injury before the development of inflammation at the sites of target organs have been implicated. This paper focuses on the several factors and components relating to glandular dysfunction and morphologic changes by nonimmunologic injury during the preinflammatory phase in mouse model, including the factors which link between innate immunity and adaptive immunity.

Genetics and genomics of Sjögren's syndrome: research provides clues to pathogenesis and novel therapies

PURPOSE

Although the key inciting events that drive the progression from autoantibodies to clinical disease remain to be clarified, new light has been shed on the factors contributing to disease susceptibility and the role of genetic factors in determining Sjögren's syndrome (SS) disease phenotypes. The purpose of this article is to provide an update on the role of genetic markers in the susceptibility to and pathogenesis of SS. This article also discusses how genomic and proteomic technology can help in the design of specific therapeutics.

KEY FINDINGS

Recent evidence suggests that inflammatory genes associated with interferon pathways, and specific regulatory genes that control the maturation and proliferation of B cells, contribute to the pathogenesis of SS. Both gene expression profiling technology and gene association studies have been used to identify these key biological pathways. Molecularly, defined subsets of pSS patients are also being revealed by these studies. Previously, identified gene loci that predispose to multiple autoimmune disorders have been confirmed supporting the paradigm of "general" autoimmune disease genes. Association of SS with many additional susceptibility loci are likely to be established through ongoing genome-wide association scans (GWAS). Clues from genetic studies suggest that targeting B cells will prove to be an effective way of reducing the systemic manifestations of pSS and are supported by early clinical trials.

SUMMARY

Genome-wide technologies are likely to identify new genes and molecular pathways in the pathogenesis of SS that will be useful not only to identify patients at risk for SS, but also to identify subsets of patients at risk for variable levels of disease severity. In the future, these studies could identify novel biomarkers that will lead to significant advances in management by providing the means to tailor therapeutic strategies to individual patients.

Laminin isoform profiles in salivary glands in Sjögren's syndrome

Five different laminin (LM) alpha, four LM-beta, and three LM-gamma chains form the 15-16 currently known approximately 400-900 kDa heterodimeric LM-monomers, which self-assemble in the lamina lucida of the basement membrane (BM) to a network, connected with nidogens and perlecans with the underlying type IV collagen network. In labial salivary glands (LSG), the structurally organizing/polarizing BM separates the tubuloacinar epithelium from the connective tissue stroma but plays regulatory roles as well. Tissue distribution of LM-alpha, -beta, and -gamma chains is described, and application of the known combinatorial rules allows some conclusions also on the corresponding distribution of the LM-trimers. Currently, known integrin (Int) and non integrin (e.g., dystroglycans and Lutheran blood group antigens) LM-receptors are described. LMs are regulated at transcriptional, translational, and posttranslational levels, together with the regulation of alternative splicing, binding partners (assembly), secretion, and degradation. In LSGs, LM-alpha1, -alpha2, and -alpha4 are only found in the acinar (not ductal) BM, LM-alpha4 also in the periductal/ interstitial stroma. Pattern recognition disclosed irregular expression in the acinar BM, suggesting some dynamic and/or regulatory role. It seems that in a female-dominant autoimmune exocrinopathy, Sjögren's syndrome (SS), LM-alpha1 and -alpha2 are decreased, together with their Int alpha1beta1 and alpha2beta1 receptors. Because LM-111/211-to-Int-alpha1beta1/alpha2beta1 interactions play a crucial role in the transdifferentiation of the intercalated duct progenitors to secretory acinar cells, acinar remodeling is impaired in SS. Disturbed hemidesmosomal Int alpha6beta4/LM-332 interactions in SS may lead to acinar cell anoikis. Interestingly, dehydroepiandrosterone (DHEA) prohormone and its intracrine androgenic dihydrotestosterone (DHT) end product upregulate at least Int alpha1beta1/alpha2beta1, whereas LM-alpha1 is upregulated by outside-in LM-111/211-to-Int-alpha1beta1/alpha2beta1 signaling. It seems that LM alterations precede the lymphocyte infiltration, suggesting that acinar BM-Int pathology, perhaps related to endo- and intracrine sex steroid metabolism, represents an early pathogenic phases in SS.