Loss of ATG5 in KRT14+ cells leads to accumulated functional impairments of salivary glands via pyroptosis

LTK deficiency induces macrophage M2 polarization and ameliorates Sjogren's syndrome by reducing chemokine CXCL13

BACKGROUND

Sjogren's syndrome (SS) is an autoimmune disease involving macrophage infiltration of the exocrine glands. LTK, a receptor tyrosine kinase, is involved in many autoimmune diseases, such as lupus erythematosus. The objectives of this study was to explore the impact of LTK on autophagy in SS.

METHODS

The NCBI Gene Expression Omnibus (GEO) database was used to screen for differentially expressed genes (DEGs) in SS patients and validated by quantitative reverse transcription PCR (RT-qPCR) in A253 cells with EGF and IFN-γ. Meanwhile, lentiviral vectors were used to transfect A253 cells for stable LTK silencing. CCK-8, flow cytometry, and transmission electron microscopy (TEM), Western blotting (WB) was employed to assess proliferation, apoptosis, autophagy, and autoimmune antigens (Ro52/SSA and La/SSB) in A253 cells. Then, macrophages were treated with 100 ng/ml of LPS to induce the polarization of macrophages towards the M1 phenotype, while macrophages were treated with IL-4 to activate the macrophage M2 phenotype. LTK-silenced A253 cells were co-cultured with macrophages. WB as well as flow cytometry were used to assess macrophage polarization markers. Furthermore, protein-antibody microarrays were utilized to analyze downstream proteins regulated by LTK. Finally, the functionality of LTK was confirmed in NOD/ShiLtJ mice.

RESULTS

LTK expression in the GEO database was increased in SS patients. And LTK was also significantly increased by EGF and IFN-γ. Knockdown of LTK increased proliferation and autophagy in A253 cells. While LTK deficiency inhibited the expression of Ro52/SSA and La/SSB, and apoptosis in A253 cells. Furthermore, LTK-silenced A253 cells promoted polarization of macrophages towards the M2 phenotype, which is associated with the pathogenesis of SS. Knockdown of LTK resulted in reduced expression of CXCL13, which in turn triggered macrophage M2 polarization. Additionally, LTK deficiency ameliorated submandibular gland tissue damage and inhibited autoimmune antigens secretion in NOD/ShiLtJ mice. In addition, the expression of autophagy markers and M2 polarization markers in the submandibular gland tissue was increased by shLTK.

CONCLUSION

LTK could promote progressive SS pathogenesis via CXCL13. This discovery indicates that targeting LTK/CXCL13 could be a potential therapeutic strategy for the clinical management of SS.

Decoding the Tumor Microenvironment of Myoepithelial Cells in Triple-Negative Breast Cancer Through Single-Cell and Transcriptomic Sequencing and Establishing a Prognostic Model Based on Key Myoepithelial Cell Genes

Background: Triple-negative breast cancer (TNBC) is an aggressive subtype with high malignancy, rapid progression, and a poor 5-year survival rate of ~77%. Due to the lack of targeted therapies, treatment options are limited, highlighting the urgent need for novel therapeutic strategies. Myoepithelial cells (MECs) in the tumor microenvironment may significantly influence TNBC development and progression. Methods: This study used single-cell RNA sequencing to compare the MEC gene expression in the normal versus TNBC tissues. TNBC-associated MECs showed increased expression of proliferation- and immune-related genes (e.g., FDCSP, KRT14, and KRT17) and decreased expression of inflammatory and extracellular matrix-related genes (e.g., CXCL8, SRGN, and DCN). Copy number variation and pseudotime analyses revealed genomic alterations and phenotypic dynamics in MECs. A CoxBoost-based prognostic model was developed and validated across 20 survival cohorts, integrating immune profiling, pathway enrichment, and drug sensitivity analyses. Mendelian randomization identified TPD52 as a TNBC risk-associated gene. siRNA knockdown of TPD52 was performed in TNBC cell lines to evaluate its effects on proliferation and migration. Results: TNBC MECs displayed significant changes in the gene expression and genomic integrity, impacting immune responses and tumor invasion. The prognostic model effectively predicted 1-, 3-, and 5-year survival outcomes, stratifying high-risk patients with enriched cell cycle and DNA replication pathways, reduced immune checkpoint expression, and chemotherapy resistance. TPD52 was identified as a tumor-promoting gene, and its knockdown suppressed TNBC cell proliferation and migration. Conclusion: This study highlights MECs' role in TNBC progression, provides a CoxBoost prognostic model for personalized treatment, and identifies TPD52 as a potential therapeutic target for TNBC intervention.

The roles of pyroptosis in the pathogenesis of autoimmune diseases

The occurrence of autoimmune diseases is a result of the immune system's immune response against healthy components of the body. Pyroptosis is an innovative form of programmed cell death dependent on inflammatory caspases, leading to the release of cytokines. Excessive pyroptosis can lead to a sustained inflammatory response, which may aggravate the development of autoimmune diseases. In rheumatoid arthritis (RA), tumor necrosis factor (TNF) and NLRP3 enhance pyroptosis, exacerbating the disease. In systemic lupus erythematosus (SLE), the release of nuclear antigen promotes the development of SLE. In multiple sclerosis (MS), elevated active caspase-11 in primary astrocytes induces oligodendrocyte pyroptosis, advancing MS progression. This review outlines the mechanisms of pyroptosis in autoimmune diseases. Meanwhile, we elaborated the possible therapeutic targets from the perspective of pyroptosis. We conclude that pyroptosis is expected to be a therapeutic target for autoimmune diseases.

Modes and Mechanisms of Salivary Gland Epithelial Cell Death in Sjogren's Syndrome

Sjogren's syndrome is an autoimmune disease in middle and old-aged women with a dry mucosal surface, which is caused by the dysfunction of secretory glands, such as the oral cavity, eyeballs, and pharynx. Pathologically, Sjogren's syndrome are characterized by lymphocyte infiltration into the exocrine glands and epithelial cell destruction caused by autoantibodies Ro/SSA and La/SSB. At present, the exact pathogenesis of Sjogren's syndrome is unclear. Evidence suggests epithelial cell death and the subsequent dysfunction of salivary glands as the main causes of xerostomia. This review summarizes the modes of salivary gland epithelial cell death and their role in Sjogren's syndrome progression. The molecular mechanisms involved in salivary gland epithelial cell death during Sjogren's syndrome as potential leads to treating the disease are also discussed.