Agomir miRNA-150-5p alleviates pristane-induced lupus by suppressing myeloid dendritic cells activation and inflammation via TREM-1 axis.

OBJECTIVE: Triggering receptors expressed on myeloid cells-1 (TREM-1) has been shown to participate in inflammatory autoimmune diseases. Nevertheless, the detailed underlying mechanisms and therapeutic benefits by targeting TREM-1 remain elusive, especially in myeloid dendritic cells (mDCs) and systemic lupus erythematosus (SLE). Disorders of epigenetic processes including non-coding RNAs give rise to SLE, resulting in complicated syndromes. Here, we aim to address this issue and explore the miRNA to inhibit the activation of mDCs and alleviate the progress of SLE by targeting TREM-1 signal axis. METHODS: Bioinformatics methods were used to analyze the differentially expressed genes (DEGs) between patients with SLE and healthy individuals by four mRNA microarray datasets from Gene Expression Omnibus (GEO). Then we identified the expression of TREM-1 and its soluble form (sTREM-1) in clinical samples by ELISA, quantitative real-time PCR and Western blot. Phenotypic and functional changes of mDCs elicited by TREM-1 agonist were determined. Three databases of miRNAs target prediction and a dual-luciferase reporter assay were used to screen and verify miRNAs that can directly inhibit TREM-1 expression in vitro. Moreover, pristane-induced lupus mice were injected with miR-150-5p agomir to evaluate the effects of miR-150-5p on mDCs in lymphatic organs and disease activity in vivo. RESULTS: We screened TREM-1 as one of the hub genes closely correlated with the progression of SLE and identified sTREM-1 in serum as a valuable diagnostic biomarker for SLE. Moreover, activation of TREM-1 by its agonist promoted activation and chemotaxis of mDCs and increased the production of inflammatory cytokines and chemokines, showing higher expression of IL-6, TNF-α, and MCP-1. We showed that lupus mice displayed a unique miRNA signature in spleen, among which miR-150 was the most significantly expressed miRNA that targeting TREM-1 compared with wild type group. Transfection of miRNA-150-5p mimics directly suppressed the expression of TREM-1 by binding to its 3' UTR. Our in vivo experiments first indicated that administration of miR-150-5p agomir effectively ameliorated lupus symptoms. Intriguingly, miR-150 inhibited the over activation of mDCs through TREM-1 signal pathway in lymphatic organs and renal tissues. CONCLUSIONS: TREM-1 represents a potentially novel therapeutic target and we identify miR-150-5p as one of the mechanisms to alleviate lupus disease, which is attributable for inhibiting mDCs activation through TREM-1 signaling pathway.

Promising roles of combined therapy based on immune response and iron metabolism in systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is an intricate autoimmune disease with diverse manifestations. Immunometabolism reprogramming contributes to the progression of SLE by regulating the phenotype and function of immune cells. Dysregulated iron metabolism is implicated in SLE pathogenesis, affecting both systemic and immune cell-specific iron homeostasis. This review explores the systemic and cellular iron handling and regulation. Additionally, the advancements regarding iron metabolism in SLE with a focus on the distinct subsets of immune cells are highlighted. By gaining insight into the interplay between iron dysregulation and immune dysfunction, the potential therapeutic avenues may be unveiled. However, challenges remain in elucidating cell-specific iron metabolic reprogramming and its contribution to SLE pathogenesis needs further research for personalized therapeutic interventions and biomarker discovery. This review provides an in-depth understanding of immune cell-specific regulatory mechanisms of iron metabolism and new insights in current challenges as well as possible clinical applications.

TIGIT as a Promising Therapeutic Target in Autoimmune Diseases.

Co-inhibitory receptors (IRs) are molecules that protect host against autoimmune reactions and maintain peripheral self-tolerance, playing an essential role in maintaining immune homeostasis. In view of the substantial clinical progresses of negative immune checkpoint blockade in cancer treatment, the role of IRs in autoimmune diseases is also obvious. Several advances highlighted the substantial impacts of T cell immunoglobulin and ITIM domain (TIGIT), a novel IR, in autoimmunity. Blockade of TIGIT pathway exacerbates multiple autoimmune diseases, whereas enhancement of TIGIT function has been shown to alleviate autoimmune settings in mice. These data suggested that TIGIT pathway can be manipulated to achieve durable tolerance to treat autoimmune disorders. In this review, we provide an overview of characteristics of TIGIT and its role in autoimmunity. We then discuss recent approaches and future directions to leverage our knowledge of TIGIT as therapeutic target in autoimmune diseases.