Wnt signaling pathway activities may be altered in primary Sjogren’s syndrome

The plasma levels of Dickkopf-1 elevated in patients with Juvenile Idiopathic Arthritis

BACKGROUND

To explore the role of two major inhibitors of Wnt signal pathway, Dickkopf-1(DKK-1) and Sclerostin (SOST), in the pathogenesis of juvenile idiopathic arthritis (JIA).

METHODS

88 patients with JIA, which including 49 patients with enthesitis-related arthritis (ERA), 21 oligoarthritis (oJIA) and 18 polyarthritis (pJIA), and 36 age-and sex-matched children as healthy controls (HC) were enrolled in this study. The plasma levels of DKK-1 and SOST, measured using commercially available ELISA kits, were analyzed the correlation between the levels of DKK-1/SOST and JIA, and were analyzed in 14 patients with JIA during before and after treatment.

RESULTS

Plasma levels of DKK-1 were significantly higher in the patients with JIA than that in HC, the elevation of DKK-1 level was positively correlated with HLA-B27 positive JIA. DKK-1 levels dropped significantly in patient with JIA after treatment (P < 0.05). There was no significant change in SOST levels among different subtypes of JIA, patients with JIA during before and after treatment, and HC.

CONCLUSION

It was suggested that the DKK-1 may have a certain correlation with the pathogenesis of JIA, and DKK-1 levels are more closely related to the HLA-B27 positive-ERA.

IMPACT

The abnormally elevated levels of Dickkopf-1 (DKK-1) may be involved in the pathogenesis of juvenile idiopathic arthritis (JIA). DKK-1 levels were more closely related to the HLA-B27 positive-enthesitis-related arthritis (ERA). DKK-1 is an inhibitor of Wnt signaling pathway that promotes osteoblastic new bone formation; it is very rare for pediatric patients with HLA-B27 positive-ERA to manifest typical spondylitis, while sacroiliac arthritis is relatively common, which may be related to the high levels of DKK-1, which is consistent with the early stage of ankylosing spondylitis (AS).

Involvement of aquaporin 5 in Sjögren's syndrome

Sjögren's syndrome (SS) is a chronic autoimmune disease with the pathological hallmark of lymphoplasmacytic infiltration of exocrine glands - more specifically salivary and lacrimal glands - resulting in a diminished production of tears and saliva (sicca syndrome). The pathophysiology underscoring the mechanisms of the sicca symptoms in SS has still yet to be unraveled but recent advances have identified a cardinal role of aquaporin-5 (AQP5) as a key player in saliva secretion as well as salivary gland epithelial cell dysregulation. AQP5 expression and localization are significantly altered in salivary glands from patients and mice models of the disease, shedding light on a putative mechanism accounting for diminished salivary flow. Furthermore, aberrant expression and localization of AQP5 protein partners, such as prolactin-inducible protein and ezrin, may account for altered AQP5 localization in salivary glands from patients suffering from SS and are considered as new players in SS development. This review provides an overview of the role of AQP5 in SS salivary gland epithelial cell dysregulation, focusing on its trafficking and protein-protein interactions.

Pathogenesis and treatment of Sjogren's syndrome: Review and update

Sjogren's syndrome (SS) is a chronic autoimmune disease accompanied by multiple lesions. The main manifestations include dryness of the mouth and eyes, along with systemic complications (e.g., pulmonary disease, kidney injury, and lymphoma). In this review, we highlight that IFNs, Th17 cell-related cytokines (IL-17 and IL-23), and B cell-related cytokines (TNF and BAFF) are crucial for the pathogenesis of SS. We also summarize the advances in experimental treatment strategies, including targeting Treg/Th17, mesenchymal stem cell treatment, targeting BAFF, inhibiting JAK pathway, et al. Similar to that of SLE, RA, and MS, biotherapeutic strategies of SS consist of neutralizing antibodies and inflammation-related receptor blockers targeting proinflammatory signaling pathways. However, clinical research on SS therapy is comparatively rare. Moreover, the differences in the curative effects of immunotherapies among SS and other autoimmune diseases are not fully understood. We emphasize that targeted drugs, low-side-effect drugs, and combination therapies should be the focus of future research.

Salivary gland tumors exhibit distinct miRNA signatures involved in Wnt/β-Catenin signaling in formalin fixed paraffin embedded tissue samples

Advances in high-throughput genomic technologies have enabled the identification of numerous selective tumor markers. However, adapting these newly identified markers to clinical practice is not always possible because most RNA molecules, including mRNAs of protein-coding genes and long non-coding RNAs, are not stable under laboratory conditions, making their testing a major challenge. In contrast to long RNA molecules, miRNAs offer a great advantage in that they are relatively stable due to their small size. Accordingly, herein we aimed to determine the expression levels of miRNAs that are involved in Wnt/β-catenin signaling pathway in formalin fixed paraffin embedded (FFPE) tissue samples of patients with salivary gland tumors. A total of 42 patients with salivary gland tumors were included in the study. The miRNA expression signatures were evaluated using the RT-qPCR. As a result, β-catenin positivity was observed in all salivary gland tumors without distinguishing between benign and malignant phenotypes. Remarkably, we found that miR-200a and miR-373 were significantly upregulated whereas miR-30c were downregulated in tissues of patients with salivary gland tumors, compared to adjacent healthy tissue samples. In addition, distinct expression signatures of these miRNAs were significantly associated with the clinicopathological findings of patients such as perineural invasion and lymph node metastasis. Additionally, miR-145 and miR-30a were found to be specifically downregulated in a mucoepidermoid carcinoma. Also, miR-26b was selectively increased in pleomorphic adenomas of the salivary gland. Collectively, our findings suggest that these miRNAs may play chief roles in the differential diagnosis of salivary gland tumors.