Involvement of CCL2 in Salivary Gland Response to Hyperosmolar Stress Related to Sjögren's Syndrome.

In primary Sjögren's syndrome (pSS) patients, salivary gland (SG) epithelial cells (SGECs) could be exposed to chronic hyperosmotic stress (HOS), consecutive to their destruction and deregulation, that exacerbates an inflammatory response. The aims of this study were to assess the mechanism accounting for C-C motif chemokine ligand 2 (CCL2) expression in an immortalized human salivary gland epithelial acinar cell line (NS-SV-AC) subjected to HOS, as well as the involvement of CCL2 in pSS. CCL2 mRNA and protein levels were determined via RT-qPCR and ELISA. Reporter plasmids and a promoter pull-down assay were used to identify transcription factors associated with CCL2 mRNA increase. Our data showed that HOS-induced CCL2 mRNA increase was independent of the nuclear factor of activated T-cells 5 (NFAT5) and nuclear factor-kappa B (NFkB) but involved Kruppel-like factor 5 (KLF5). CCL2 protein levels, quantified by enzyme-linked immunosorbent assay (ELISA) in sera samples from pSS patients, correlated with the European Alliance of Associations for Rheumatology's Sjogren's syndrome disease activity index (ESSDAI) score for systemic activity. In addition, CCL2 protein levels were higher in patients with biological activity, cutaneous manifestations, and ESSDAI score superior or equal to five. Our data suggest that chronic HOS could exacerbate pSS disease by contributing to the inflammatory process induced by the expression and secretion of CCL2.

Intense Pulsed Light Therapy in the Treatment of Dry Eye Diseases: A Systematic Review and Meta-Analysis.

BACKGROUND: Intense pulsed light therapy (IPL) is a recently developed way of treating dry eye disease (DED). During the last decade, there was a multiplication of trials studying IPL efficacy. The goal of this review is to summarize the most important and significant results of these trials estimating effect sizes. METHODS: The PubMed and sciencedirect databases were searched using a PICO model-based approach. Randomized controlled trials including at least 20 patients with DED and no other eye condition, with a control group and break-up time or symptom scores data available for extraction were included in this review. Statistical analysis evaluated the tear break-up time (TBUT), non-invasive break-up time (NIBUT), ocular surface disease index (OSDI), and standard patient evaluation of eye dryness (SPEED). Three comparisons were carried on for each outcome: longest follow-up values vs. baseline in the treatment group, longest follow-up values in the treatment group vs. control group, and changes from baseline in the treatment group vs. control group. A subgroup analysis was carried on. RESULTS: Eleven randomized controlled trials, published between 2015 and 2021 were included in this systematic review with 759 patients in total. The longest follow-up values vs. baseline in the treatment group analyses were significantly in favor of IPL for all the parameters studied for instance: NIBUT (effect size (ES), 2.02; 95% confidence interval (CI), (1.43; 2.62)), TBUT (ES, 1.83; 95% CI, (0.96; 2.69)), OSDI (ES, -1.38; 95% CI, (-2.12; -0.64)) and SPEED (ES, -1.15; 95% CI, (-1.72; -0.57)). The longest follow-up values in the treatment group vs. control group analyses, and, the change from baseline in the treatment group vs. control group analyses, were both significantly in favor of IPL for NIBUT, TBUT, and SPEED but not for OSDI. CONCLUSIONS: IPL seems to have a positive effect on tear stability evaluated by the break-up times. However, the effect on DED symptoms is less clear. Some confounding factors such as the age and the IPL device used influence the results indicating that the ideal settings still need to be found and personalized for the patient.

Aquaporin-5 Dynamic Regulation.

Aquaporin-5 (AQP5), belonging to the aquaporins (AQPs) family of transmembrane water channels, facilitates osmotically driven water flux across biological membranes and the movement of hydrogen peroxide and CO2. Various mechanisms have been shown to dynamically regulate AQP5 expression, trafficking, and function. Besides fulfilling its primary water permeability function, AQP5 has been shown to regulate downstream effectors playing roles in various cellular processes. This review provides a comprehensive overview of the current knowledge of the upstream and downstream effectors of AQP5 to gain an in-depth understanding of the physiological and pathophysiological processes involving AQP5.

Addressing the clinical unmet needs in primary Sjögren's Syndrome through the sharing, harmonization and federated analysis of 21 European cohorts.

For many decades, the clinical unmet needs of primary Sjögren's Syndrome (pSS) have been left unresolved due to the rareness of the disease and the complexity of the underlying pathogenic mechanisms, including the pSS-associated lymphomagenesis process. Here, we present the HarmonicSS cloud-computing exemplar which offers beyond the state-of-the-art data analytics services to address the pSS clinical unmet needs, including the development of lymphoma classification models and the identification of biomarkers for lymphomagenesis. The users of the platform have been able to successfully interlink, curate, and harmonize 21 regional, national, and international European cohorts of 7,551 pSS patients with respect to the ethical and legal issues for data sharing. Federated AI algorithms were trained across the harmonized databases, with reduced execution time complexity, yielding robust lymphoma classification models with 85% accuracy, 81.25% sensitivity, 85.4% specificity along with 5 biomarkers for lymphoma development. To our knowledge, this is the first GDPR compliant platform that provides federated AI services to address the pSS clinical unmet needs.

Ezrin Is a Novel Protein Partner of Aquaporin-5 in Human Salivary Glands and Shows Altered Expression and Cellular Localization in Sjögren's Syndrome.

Sjögren's syndrome (SS) is an exocrinopathy characterized by the hypofunction of salivary glands (SGs). Aquaporin-5 (AQP5); a water channel involved in saliva formation; is aberrantly distributed in SS SG acini and contributes to glandular dysfunction. We aimed to investigate the role of ezrin in AQP5 mislocalization in SS SGs. The AQP5-ezrin interaction was assessed by immunoprecipitation and proteome analysis and by proximity ligation assay in immortalized human SG cells. We demonstrated, for the first time, an interaction between ezrin and AQP5. A model of the complex was derived by computer modeling and in silico docking; suggesting that AQP5 interacts with the ezrin FERM-domain via its C-terminus. The interaction was also investigated in human minor salivary gland (hMSG) acini from SS patients (SICCA-SS); showing that AQP5-ezrin complexes were absent or mislocalized to the basolateral side of SG acini rather than the apical region compared to controls (SICCA-NS). Furthermore, in SICCA-SS hMSG acinar cells, ezrin immunoreactivity was decreased at the acinar apical region and higher at basal or lateral regions, accounting for altered AQP5-ezrin co-localization. Our data reveal that AQP5-ezrin interactions in human SGs could be involved in the regulation of AQP5 trafficking and may contribute to AQP5-altered localization in SS patients.

Unraveling Human AQP5-PIP Molecular Interaction and Effect on AQP5 Salivary Glands Localization in SS Patients.

Saliva secretion requires effective translocation of aquaporin 5 (AQP5) water channel to the salivary glands (SGs) acinar apical membrane. Patients with Sjögren's syndrome (SS) display abnormal AQP5 localization within acinar cells from SGs that correlate with sicca manifestation and glands hypofunction. Several proteins such as Prolactin-inducible protein (PIP) may regulate AQP5 trafficking as observed in lacrimal glands from mice. However, the role of the AQP5-PIP complex remains poorly understood. In the present study, we show that PIP interacts with AQP5 in vitro and in mice as well as in human SGs and that PIP misexpression correlates with an altered AQP5 distribution at the acinar apical membrane in PIP knockout mice and SS hMSG. Furthermore, our data show that the protein-protein interaction involves the AQP5 C-terminus and the N-terminal of PIP (one molecule of PIP per AQP5 tetramer). In conclusion, our findings highlight for the first time the role of PIP as a protein controlling AQP5 localization in human salivary glands but extend beyond due to the PIP-AQP5 interaction described in lung and breast cancers.

The Involvement of Innate and Adaptive Immunity in the Initiation and Perpetuation of Sjögren's Syndrome.

Sjogren's syndrome (SS) is a chronic autoimmune disease characterized by the infiltration of exocrine glands including salivary and lachrymal glands responsible for the classical dry eyes and mouth symptoms (sicca syndrome). The spectrum of disease manifestations stretches beyond the classical sicca syndrome with systemic manifestations including arthritis, interstitial lung involvement, and neurological involvement. The pathophysiology underlying SS is not well deciphered, but several converging lines of evidence have supported the conjuncture of different factors interplaying together to foster the initiation and perpetuation of the disease. The innate and adaptive immune system play a cardinal role in this process. In this review, we discuss the inherent parts played by both the innate and adaptive immune system in the pathogenesis of SS.

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.

Involvement of Aquaporins in the Pathogenesis, Diagnosis and Treatment of Sjögren's Syndrome.

Sjögren's syndrome (SS) is a chronic autoimmune disease characterized by lymphocytic infiltration of salivary and lacrimal glands resulting in diminished production of saliva and tears. The pathophysiology of SS has not yet been fully deciphered. Classically it has been postulated that sicca symptoms in SS patients are a double step process whereby lymphocytic infiltration of lacrimal and salivary glands (SG) is followed by epithelial cell destruction resulting in keratoconjunctivitis sicca and xerostomia. Recent advances in the field of the pathophysiology of SS have brought in new players, such as aquaporins (AQPs) and anti AQPs autoantibodies that could explain underlying mechanistic processes and unveil new pathophysiological pathways offering a deeper understanding of the disease. In this review, we delineate the link between the AQP and SS, focusing on salivary glands, and discuss the role of AQPs in the treatment of SS-induced xerostomia.

Dermatomyositis Associated with Sarcoidosis: Two Cases.

Dermatomyositis (DM) and sarcoidosis are two idiopathic systemic disorders. Reports of patients with both conditions are extremely rare. Here we describe two patients who presented with DM and DM-associated antibodies, and later developed biopsy-proven sarcoidosis. There are increasing reports of the occurrence of sarcoidosis in the context of autoimmune diseases. These observations might imply similarities in the pathogenetic mechanisms. LEARNING POINTS: Sarcoidosis should be considered in patients with dermatomyositis (DM) presenting with enlarged lymph nodes. Contrary to the principle of Occam's razor, in this case one diagnosis does not rule out the other.The pathophysiology of sarcoidosis and DM involves both Th1 and Th17 inflammatory responses, which may explain the overlap of these two diseases.

Aquaporin-4 overexpression in rat ALS model.

Onset of motoneuron death characterizing amyotrophic lateral sclerosis (ALS) is closely linked to modified astrocytic and glial environments. Here, we show that in the spinal cord from transgenic rat overexpressing mutated human SOD1, aquaporin-4 mRNA and protein are specifically overexpressed in the gray matter at end stage of disease. Immunohistochemistry and double immunofluorescence allowed to detect, in the spinal cord gray matter of the ALS rat, increased aquaporin-4 surrounding both vessel and motoneuron perikarya. The use of pre-embedding immunohistochemistry at electron microscopic level confirmed such localization associated with swollen astrocytic processes surrounding the vessels. The AQP4 immunohistochemical labeling surrounding several motoneuron perikarya was only seen in ALS rats. Identification of this AQP4-positive cellular type remains unclear.