Anti-Ro/SSA autoantibody-mediated regulation of extracellular matrix fibulins in human epithelial cells of the salivary gland

Extracellular matrix turnover in salivary gland disorders and regenerative therapies: Obstacles and opportunities

Salivary gland (SG) extracellular matrix (ECM) has a major influence on tissue development, homeostasis, and tissue regeneration after injury. During aging, disease, and physical insult, normal remodeling of the SG microenvironment (i.e. ECM) becomes dysregulated, leading to alterations in matrix composition which disrupt tissue architecture/structure, alter cell activity, and negatively impact gland function. Matrix metalloproteinases (MMPs) are a large and diverse family of metalloendopeptidases which play a major role in matrix degradation and are intimately involved in regulating development and cell function; dysregulation of these enzymes leads to the production of a fibrotic matrix. In the SG this altered fibrotic ECM (or cell microenvironment) negatively impacts normal cell function and the effectiveness of gene and stem cell therapies which serve as a foundation for many SG regenerative therapies. For this reason, prospective regenerative strategies should prioritize the maintenance and/or restoration of a healthy SG ECM. Mesenchymal stem cells (MSCs) have great potential for mitigating damage to the SG microenvironment by ameliorating inflammation, reducing fibrosis, and repairing the damaged milieu of extracellular regulatory cues, including the matrix. This review addresses our current understanding of the impact of aging and disease on the SG microenvironment and suggests critical deficiencies and opportunities in ECM-targeted therapeutic interventions.

Unveiling the mystery of Riehl's melanosis: An update from pathogenesis, diagnosis to treatment

Riehl's melanosis is a hyperpigmentation disorder that has a significant psychological and social impact on individuals. In the past 10 years, new categories have been developed, raising questions about how to classify Riehl's melanosis. The mechanism of this disease remains unclear, although the type IV hypersensitivity response caused by allergic sensitization, as well as genetic, ultraviolet radiation, and autoimmune factors, is to blame. Clinical manifestation, dermoscopy, reflectance confocal microscopy, patch/photopatch testing, histopathology, and a novel multimodality skin imaging system have been used for the diagnosis. A variety of therapies including topical skin-lightening agents, oral tranexamic acid, glycyrrhizin compound, chemical peels, and lasers and light therapies (intense pulsed light, 1064-nm Q-Switched Nd: YAG laser, 755-nm PicoWay laser, nonablative 1927-nm fractional thulium fiber laser, new pulsed-type microneedling radiofrequency), with improved effectiveness. The latest findings on possible biomarkers and their relationship to other autoimmune diseases were also summarized.

The Aberrant Levels of Decorin Induce Damages of Human Salivary Gland Epithelial Cells and Polarization of Macrophages

OBJECTIVE

This study aimed to preliminarily address the levels of decorin (DCN, a critical component of extracellular matrix), and its potential roles in primary sjögren's syndrome (pSS).

METHODS

DCN levels were determined in the salivary glands of experimental SS (ESS) mice and pSS patients by RNA sequencing, bioinformatics analysis, or immunohistochemical (IHC) staining. Its correlation with interested genes and co-localization with a putative receptor was studied in pSS patients. In addition, its potential roles on salivary gland epithelium and macrophages were tested by exogenous administration to corresponding cell lines, followed by the evaluation of apoptosis using flow cytometry or cytokines expression using quantitative real time PCR.

RESULTS

Our data revealed a significant elevation of DCN in the salivary glands of experimental SS (ESS) mice model and pSS patients. In addition, the bioinformatics analysis of DCN in GSE40611 (RNA-seq, parotid glands) dataset displayed an elevation of DCN level in the parotid glands of pSS patients that positively correlated with several chemokines (CXCL13, CXCL9, CCL20), IL-1ß, and caspase3 but negatively correlated with the proliferation relative gene MKI67. The stimulatory effects of DCN on the salivary gland epithelial cells (A253 cell line) and macrophages have been determined as they are considered active participants in the progression of SS. The data showed that DCN induced apoptosis of A253 cells and polarization of macrophages toward the M1 phenotype, characterized by the expression of pro-inflammatory cytokines.

CONCLUSION

Our study provided preliminary evidence to understand the clinical significance of DCN in pSS and broadened our horizons in understanding the mechanism of pSS.

Understanding the Complexity of Sjögren's Syndrome: Remarkable Progress in Elucidating NF-κB Mechanisms

Sjögren’s syndrome (SS) is a systemic autoimmune inflammatory disease with a poorly defined aetiology, which targets exocrine glands (particularly salivary and lachrymal glands), affecting the secretory function. Patients suffering from SS exhibit persistent xerostomia and keratoconjunctivitis sicca. It is now widely acknowledged that a chronic grade of inflammation plays a central role in the initiation, progression, and development of SS. Consistent with its key role in organizing inflammatory responses, numerous recent studies have shown involvement of the transcription factor nuclear factor κ (kappa)-light-chain-enhancer of activated B cells (NF-κB) in the development of this disease. Therefore, chronic inflammation is considered as a critical factor in the disease aetiology, offering hope for the development of new drugs for treatment. The purpose of this review is to describe the current knowledge about the NF-κB-mediated molecular events implicated in the pathogenesis of SS.

Fibulin-2 inhibits development of gastric cancer by downregulating β-catenin

The aim of the present study was to investigate the expression of fibulin-2 and β-catenin in gastric cancer tissues and the association to mutual regulation. Forty-nine cases of gastric cancer specimens obtained via surgical resection in the Pathology Department of Heping Hospital Affiliated to Changzhi Medical College from March 2013 to August 2017 were collected. The expression levels of fibulin-2 and β-catenin in 49 cases of gastric cancer and para-carcinoma tissues were detected via quantitative polymerase chain reaction and immunohistochemistry. The correlation of expression of fibulin-2 and β-catenin proteins in gastric cancer was detected via Spearman's analysis. The correlation of fibulin-2 and β-catenin protein expression with clinicopathological indexes of patients was also analyzed. Moreover, the fibulin-2 overexpression plasmid was constructed and transfected into human gastric cancer AGS and SGC-790 cell lines, so as to observe changes in β-catenin and its downstream indexes. Fibulin-2 messenger ribonucleic acid (mRNA) level in gastric cancer tissues was significantly lower than that in para-carcinoma tissues, while β-catenin mRNA level was significantly increased (P<0.05). The positive rate of fibulin-2 protein was 73.47% (36/49) in gastric cancer tissues and 16.33% (8/49) in para-carcinoma tissues, while that of β-catenin was 77.55% (38/49) in gastric cancer tissues and 28.57% (14/49) in para-carcinoma tissues, indicating that fibulin-2 protein is significantly deleted in gastric cancer tissues, and β-catenin protein is significantly upregulated (P<0.001). Fibulin-2 and β-catenin had a negative correlation (r=−0.361, P=0.003), but was closely correlated with the tumor size and lymph node metastasis (P<0.05). After overexpression of fibulin-2, expression of β-catenin, cyclin D1 and c-Myc protein was obviously downregulated (P<0.05). The tumor suppressor gene, fibulin-2, is significantly deleted in gastric cancer tissues, while β-catenin is remarkably enriched. Overexpression of fibulin-2 can inhibit the development of gastric cancer by downregulating β-catenin.

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.

Cell adhesion protein fibulin-7 and its C-terminal fragment negatively regulate monocyte and macrophage migration and functions in vitro and in vivo

Fibulin-7 (Fbln7) has been identified as the latest member of the fibulin family of secreted glycoproteins in developing teeth, functioning as a cell adhesion molecule and interacting with other matrix proteins, receptors, and growth factors. More recently, we have shown that the C-terminal Fbln7 fragment (Fbln7-C) has antiangiogenic activity in vitro. Fbln7 is also expressed in immune-privileged tissues, such as eye and placenta, but its functional significance is unknown. In the current study, we show that human monocytes adhere to both full-length Fbln7 (Fbln7-FL) and Fbln7-C, in part, via integrins α₅β₁ and α₂β₁. Morphologic studies and surface expression analyses of CD14, mannose receptor (CD206), major histocompatibility complex II, and CD11b receptors revealed that both Fbln7-FL and Fbln7-C inhibit M-CSF-induced monocyte differentiation. Fbln7-C had significantly greater negative effects on cell spreading and stress fiber formation, including the production of IL-6 and metalloproteinase-1/-9 compared with Fbln7-FL. Furthermore, in an LPS-induced systemic inflammation model, Fbln7-C and Fbln7-FL reduced the infiltration of immune cells, such as neutrophils and macrophages, to the inflamed peritoneum. Thus, these results suggest that Fbln7 and Fbln7-C could modulate the activity of immune cells and have therapeutic potential for inflammatory diseases.-Sarangi, P. P., Chakraborty, P., Dash, S. P., Ikeuchi, T., de Vega, S., Ambatipudi, K., Wahl, L., Yamada, Y. Cell adhesion protein fibulin-7 and its C-terminal fragment negatively regulate monocyte and macrophage migration and functions in vitro and in vivo.

X-linked ectodermal dysplasia receptor (XEDAR) gene silencing prevents caspase-3-mediated apoptosis in Sjögren's syndrome

Despite recent advancements in the knowledge of the etiology and pathogenic mechanisms, treatment of the autoimmune disease Sjögren's syndrome (SS) remains mostly empiric and symptom-based, indicating the need for novel therapeutic approaches. Ectodysplasin-A2 (EDA-A2) is a recently isolated member of the tumor necrosis factor superfamily that binds to X-linked ectodermal dysplasia receptor (XEDAR). In this report, we have analyzed the expression and the biological activity of EDA-A2 in human salivary gland epithelial cells (SGEC) from primary Sjögren's syndrome (pSS) patients. We report that EDA-A2 and its receptor XEDAR are overexpressed in pSS SGEC in comparison with healthy individuals and that the EDA-A2/XEDAR system in these cells is involved in the induction of apoptosis via caspases activation. Collectively, our results suggest that EDA-A2/XEDAR system may be a promising agent for the gene therapy of pSS.

Salivary gland expression level of IκBα regulatory protein in Sjögren's syndrome

Diagnosis and therapeutic strategies in Sjögren's syndrome (SS) might greatly benefit of the present multidisciplinary approach to studying the molecular pathogenesis of the disease. A deregulated inflammatory response has been described in the SS. The research in the last years sheds light on the importance of the NF-κB pathway regulating the pro-inflammatory cytokine production and leukocyte recruitment. These are important contributors to the inflammatory response during the development of SS. In this study we examine the expression of the NF-κB inhibitory protein termed IκBα in salivary glands epithelial cells (SGEC) comparing it with SGEC from healthy controls, to test the hypothesis that an altered expression of IκBα occurs in SGEC from SS biopsies. Real-Time PCR, western blot and immunohistochemistry demonstrated that the expression level of IκBα was significantly lower in SS with respect to healthy controls leading to an increased NF-κB activity. Our results suggest that the analysis of IκBα expression at salivary gland epithelial cell level could be a potential new hallmark of SS progression and sustain a rationale to more deeply investigate the therapeutic potential of specific NF-κB inhibitors in SS.