CircPTPN22 modulates T-cell activation by sponging miR-4689 to regulate S1PR1 expression in patients with systemic lupus erythematosus.

BACKGROUND: Circular RNAs are involved in autoimmune disease pathogenesis. Our previous study indicated that circPTPN22 is involved in autoimmune diseases, such as systemic lupus erythematosus (SLE) and rheumatoid arthritis, but the underlying mechanisms remain unclear. METHODS: First, the expression of circPTPN22 was detected by real-time PCR and western blotting. After overexpression or knockdown of circPTPN22, the proliferation of Jurkat cells was detected by the CCK-8 assay, and the apoptosis of Jurkat cells was detected by flow cytometry. In addition, the relationship between circPTPN22-miR-4689-S1PR1 was confirmed by bioinformatic analyses, fluorescence in situ hybridization assays, RNA-binding protein immunoprecipitation, and dual luciferase reporter assays. RESULTS: We found that circPTPN22 expression was downregulated in the PBMCs of SLE patients compared to those of healthy controls. Overexpression of circPTPN22 increased proliferation and inhibited apoptosis of Jurkat T cells, whereas knockdown of circPTPN22 exerted the opposite effects. CircPTPN22 acts as a miR-4689 sponge, and S1PR1 is a direct target of miR-4689. Importantly, the circPTPN22/miR-4689/S1PR1 axis inhibited the secretion of TNF-α and IL-6 in Jurkat T cells. CONCLUSIONS: CircPTPN22 acts as a miR-4689 sponge to regulate T-cell activation by targeting S1PR1, providing a novel mechanism for the pathogenesis of SLE.

T Cell Subsets and the Expression of Related MicroRNAs in Patients with Recurrent Early Pregnancy Loss.

This study explored the role of T cell subsets and the expression of related microRNAs in patients with recurrent early pregnancy loss (EPL). Fifty patients with EPL loss between May 2018 and May 2021 were randomly selected as the EPL group, and 50 pregnant women with normal pregnancies or normal delivery outcomes were randomly selected as the control group. The expression levels of T cell subset-related markers and T cell subset-related miRNAs, in addition to the frequencies of T cell subsets, in peripheral blood of the two groups were analyzed. In terms of T cell-related markers, the results showed that the expression levels of the transcriptional regulator TBX-21 (T-bet) and interferon regulatory factor 4 (IRF4) were significantly upregulated in peripheral blood of the patients in the EPL group (P < 0.05), whereas the expression levels of GATA binding protein 3 (GATA3) and glucocorticoid-induced tumor necrosis factor receptor (GITR) were significantly downregulated (P < 0.05). In the EPL group, the expression of mir-106b, mir-93, and mir-25 was upregulated (1.51 ± 0.129, 1.43 ± 0.132, and 1.73 ± 0.156, respectively) in regulatory T (Treg) cell-related T cell subsets, whereas the expression of miR-146a and miR-155 was downregulated (P < 0.05). The frequencies of Treg and exhausted T cells in the EPL group were significantly lower than those in the control group (P < 0.05). The cell frequencies of T helper 17 (Th17) cells and exhausted Treg cells in the EPL group were significantly higher than those in the control group (P < 0.05). In conclusion, immune cells and associated miRNA profiles can be used as prognostic biomarkers for the treatment of human reproductive disorders, such as EPL.

Current Progress in Treating Systemic Lupus Erythematosus Using Exosomes/MicroRNAs.

Systemic lupus erythematosus (SLE) is a chronic systemic autoimmune disease associated with impaired organ functions that can seriously affect the daily life of patients. Recent SLE therapies frequently elicit adverse reactions and side effects in patients, and clinical heterogeneity is considerable. Mesenchymal stromal cells (MSCs) have anti-inflammatory, tissue repair, and immunomodulatory properties. Their ability to treat autoimmune diseases largely depends on secreted extracellular vesicles, especially exosomes. The effects of exosomes and microRNAs (miRNAs) on SLE have recently attracted interest. This review summarizes the applications of MSCs derived from bone marrow, adipocyte tissue, umbilical cord, synovial membrane, and gingival tissue, as well as exosomes to treating SLE and the key roles of miRNAs. The efficacy of MSCs infusion in SLE patients with impaired autologous MSCs are reviewed, and the potential of exosomes and their contents as drug delivery vectors for treating SLE and other autoimmune diseases in the future are briefly described.

Potential Mechanisms Between HF and COPD: New Insights From Bioinformatics.

Heart failure (HF) and chronic obstructive pulmonary disease (COPD) are closely related in clinical practice. This study aimed to investigate the co-genetic characteristics and potential molecular mechanisms of HF and COPD. HF and COPD datasets were downloaded from gene expression omnibus database. After identifying common differentially expressed genes (DEGs), the functional analysis highlighted the critical role of extracellular matrix and ribosomal signaling pathways in both diseases. In addition, GeneMANIA's results suggested that the 2 diseases were related to immune infiltration, and CIBERSORT suggested the role of macrophages. We also discovered 4 TFs and 1408 miRNAs linked to both diseases, and salbutamol may positively affect them.

Clinical Value and Mechanism of Long Non-Coding RNA UCA1 in Acute Respiratory Distress Syndrome Induced by Cardiopulmonary Bypass.

AIM: Long non-coding RNA (lncRNA) can be used as a biological marker for the diagnosis and treatment of various diseases. The study aimed to detect changes in the expression of lncRNA for urothelial carcinoma associated 1 (UCA1) in patients with cardiopulmonary bypass (CPB)-induced acute respiratory distress syndrome (ARDS). Clinical values and cell function in ARDS were explored. METHOD: In total, 195 patients without CPB-induced ARDS were included in the control group, and 85 patients with ARDS were included in the ARDS group. Serum UCA1 levels were measured by quantitative real-time polymerase chain reaction. A549 was used for the cell experiments by establishing oxygen-glucose deprivation/reperfusion (OGD/R) cell models, and the cell viability and apoptosis were tested. The concentration of inflammatory factors was tested by an enzyme-linked immunosorbent assay. A luciferase reporting assay was applied for target gene analysis. RESULTS: Quantitative real-time polymerase chain reaction revealed a gradual increase in serum UCA1 in both control and ARDS cases, and patients with ARDS had higher levels of UCA1 than those in the control group. Serum UCA1 was positively correlated with serum tumour necrosis factor-α and interleukin-6 concentration in patients with ARDS. UCA1 had the ability to distinguish patients with ARDS from those without it. UCA1 inhibition protected against lung injury and inhibited cell inflammation in vitro. MicroRNA (miR-182-5p) was downregulated in OGD/R-induced cell models and sponged by UCA1. CONCLUSIONS: Elevated expression of UCA1 may be associated with the occurrence of ARDS after CPB surgery. The regulatory role of UCA1 in ARDS might be related to inflammation and downregulated miR-182-5p in alveolar epithelial cells.

m(6)A methyltransferase METTL3 relieves cognitive impairment of hyperuricemia mice via inactivating MyD88/NF-κB pathway mediated NLRP3-ASC-Caspase1 inflammasome.

BACKGROUND: Recent studies have uncovered that hyperuricemia (HUA) leads to cognitive deficits, which are accompanied by neuronal damage and neuroinflammation. Here, we aim to explore the role of methyltransferase-like 3 (METTL3) in HUA-mediated neuronal apoptosis and microglial inflammation. METHODS: A HUA mouse model was constructed. The spatial memory ability of the mice was assessed by the Morris water maze experiment (MWM), and neuronal apoptosis was analyzed by the TdT-mediated dUTP nick end labeling (TUNEL) assay. Besides, enzyme-linked immunosorbent assay (ELISA) was utilized to measure the contents of inflammatory factors (IL-1ß, IL-6, and TNF-α) and oxidative stress markers (MDA, SOD, and CAT) in the serum of mice. In vitro, the mouse hippocampal neuron (HT22) and microglia (BV2) were treated with uric acid (UA). Flow cytometry was applied to analyze HT22 and BV2 cell apoptosis, and ELISA was conducted to observe neuroinflammation and oxidative stress. In addition, the expression of MyD88, p-NF-κB, NF-κB, NLRP3, ASC and Caspase1 was determined by Western blot. RESULTS: METTL3 and miR-124-3p were down-regulated, while the MyD88-NF-κB pathway was activated in the HUA mouse model. UA treatment induced neuronal apoptosis in HT22 and stimulated microglial activation in BV2. Overexpressing METTL3 alleviated HT22 neuronal apoptosis and resisted the release of inflammatory cytokines and oxidative stress mediators in BV2 cells. METTL3 repressed MyD88-NF-κB and NLRP3-ASC-Caspase1 inflammasome. In addition, METTL3 overexpression enhanced miR-124-3p expression, while METTL3 knockdown aggravated HT22 cell apoptosis and BV2 cell overactivation. CONCLUSION: METTL3 improves neuronal apoptosis and microglial activation in the HUA model by choking the MyD88/NF-κB pathway and up-regulating miR-124-3p.

Monocytes educated by cancer-associated fibroblasts secrete exosomal miR-181a to activate AKT signaling in breast cancer cells.

BACKGROUND: Cancer-associated fibroblasts (CAFs), one of the major components of the tumor stroma, contribute to an immunosuppressive tumor microenvironment (TME) through the induction and functional polarization of protumoral macrophages. We have herein investigated the contribution of CAFs to monocyte recruitment and macrophage polarization. We also sought to identify a possible paracrine mechanism by which CAF-educated monocytes affect breast cancer (BC) cell progression. METHODS: Monocytes were educated by primary CAFs and normal fibroblast (NF); the phenotypic alterations of CAF- or NF-educated monocytes were measured by flow cytometry. Exosomes isolated from the cultured conditioned media of the educated monocytes were characterized. An in vivo experiment using a subcutaneous transplantation tumor model in athymic nude mice was conducted to uncover the effect of exosomes derived from CAF- or NF-educated monocytes on breast tumor growth. Gain- and loss-of-function experiments were performed to explore the role of miR-181a in BC progression with the involvement of the AKT signaling pathway. Western blotting, enzyme-linked immunosorbent assay, RT-qPCR, flow cytometry staining, migration assay, immunohistochemical staining, and bioinformatics analysis were performed to reveal the underlying mechanisms. RESULTS: We illustrated that primary CAFs recruited monocytes and established pro-tumoral M2 macrophages. CAF may also differentiate human monocyte THP-1 cells into anti-inflammatory M2 macrophages. Besides, we revealed that CAFs increased reactive oxygen species (ROS) generation in THP-1 monocytes, as differentiating into M2 macrophages requires a level of ROS for proper polarization. Importantly, T-cell proliferation was suppressed by CAF-educated monocytes and their exosomes, resulting in an immunosuppressive TME. Interestingly, CAF-activated, polarized monocytes lost their tumoricidal abilities, and their derived exosomes promoted BC cell proliferation and migration. In turn, CAF-educated monocyte exosomes exhibited a significant promoting effect on BC tumorigenicity in vivo. Of clinical significance, we observed that up-regulation of circulating miR-181a in BC was positively correlated with tumor aggressiveness and found a high level of this miRNA in CAF-educated monocytes and their exosomes. We further clarified that the pro-oncogenic effect of CAF-educated monocytes may depend in part on the exosomal transfer of miR-181a through modulating the PTEN/Akt signaling axis in BC cells. CONCLUSIONS: Our findings established a connection between tumor stromal communication and tumor progression and demonstrated an inductive function for CAF-educated monocytes in BC cell progression. We also proposed a supporting model in which exosomal transfer of miR-181a from CAF-educated monocytes activates AKT signaling by regulating PTEN in BC cells.

CD146+ Endometrial-Derived Mesenchymal Stem/Stromal Cell Subpopulation Possesses Exosomal Secretomes with Strong Immunomodulatory miRNA Attributes.

The perivascular localization of endometrial mesenchymal stem/stromal cells (eMSC) allows them to sense local and distant tissue damage, promoting tissue repair and healing. Our hypothesis is that eMSC therapeutic effects are largely exerted via their exosomal secretome (eMSC EXOs) by targeting the immune system and angiogenic modulation. For this purpose, EXOs isolated from Crude and CD146+ eMSC populations were compared for their miRNA therapeutic signatures and immunomodulatory functionality under inflammatory conditions. eMSC EXOs profiling revealed 121 in Crude and 88 in CD146+ miRNAs, with 82 commonly present in both populations. Reactome and KEGG analysis of miRNAs highly present in eMSC EXOs indicated their involvement among others in immune system regulation. From the commonly present miRNAs, four miRNAs (hsa-miR-320e, hsa-miR-182-3p, hsa-miR-378g, hsa-let-7e-5p) were more enriched in CD146+ eMSC EXOs. These miRNAs are involved in macrophage polarization, T cell activation, and regulation of inflammatory cytokine transcription (i.e., TNF-α, IL-1ß, and IL-6). Functionally, stimulated macrophages exposed to eMSC EXOs demonstrated a switch towards an alternate M2 status and reduced phagocytic capacity compared to stimulated alone. However, eMSC EXOs did not suppress stimulated human peripheral blood mononuclear cell proliferation, but significantly reduced secretion of 13 pro-inflammatory molecules compared to stimulated alone. In parallel, two anti-inflammatory proteins, IL-10 and IL-13, showed higher secretion, especially upon CD146+ eMSC EXO exposure. Our study suggests that eMSC, and even more, the CD146+ subpopulation, possess exosomal secretomes with strong immunomodulatory miRNA attributes. The resulting evidence could serve as a foundation for eMSC EXO-based therapeutics for the resolution of detrimental aspects of tissue inflammation.

Long noncoding RNA uc.230/CUG-binding protein 1 axis sustains intestinal epithelial homeostasis and response to tissue injury.

Intestinal epithelial integrity is commonly disrupted in patients with critical disorders, but the exact underlying mechanisms are unclear. Long noncoding RNAs transcribed from ultraconserved regions (T-UCRs) control different cell functions and are involved in pathologies. Here, we investigated the role of T-UCRs in intestinal epithelial homeostasis and identified T-UCR uc.230 as a major regulator of epithelial renewal, apoptosis, and barrier function. Compared with controls, intestinal mucosal tissues from patients with ulcerative colitis and from mice with colitis or fasted for 48 hours had increased levels of uc.230. Silencing uc.230 inhibited the growth of intestinal epithelial cells (IECs) and organoids and caused epithelial barrier dysfunction. Silencing uc.230 also increased IEC vulnerability to apoptosis, whereas increasing uc.230 levels protected IECs against cell death. In mice with colitis, reduced uc.230 levels enhanced mucosal inflammatory injury and delayed recovery. Mechanistic studies revealed that uc.230 increased CUG-binding protein 1 (CUGBP1) by acting as a natural decoy RNA for miR-503, which interacts with Cugbp1 mRNA and represses its translation. These findings indicate that uc.230 sustains intestinal mucosal homeostasis by promoting epithelial renewal and barrier function and that it protects IECs against apoptosis by serving as a natural sponge for miR-503, thereby preserving CUGBP1 expression.

CD11c+ myeloid cell exosomes reduce intestinal inflammation during colitis.

Intercellular communication is critical for homeostasis in mammalian systems, including the gastrointestinal (GI) tract. Exosomes are nanoscale lipid extracellular vesicles that mediate communication between many cell types. Notably, the roles of immune cell exosomes in regulating GI homeostasis and inflammation are largely uncharacterized. By generating mouse strains deficient in cell-specific exosome production, we demonstrate deletion of the small GTPase Rab27A in CD11c+ cells exacerbated murine colitis, which was reversible through administration of DC-derived exosomes. Profiling RNAs within colon exosomes revealed a distinct subset of miRNAs carried by colon- and DC-derived exosomes. Among antiinflammatory exosomal miRNAs, miR-146a was transferred from gut immune cells to myeloid and T cells through a Rab27-dependent mechanism, targeting Traf6, IRAK-1, and NLRP3 in macrophages. Further, we have identified a potentially novel mode of exosome-mediated DC and macrophage crosstalk that is capable of skewing gut macrophages toward an antiinflammatory phenotype. Assessing clinical samples, RAB27A, select miRNAs, and RNA-binding proteins that load exosomal miRNAs were dysregulated in ulcerative colitis patient samples, consistent with our preclinical mouse model findings. Together, our work reveals an exosome-mediated regulatory mechanism underlying gut inflammation and paves the way for potential use of miRNA-containing exosomes as a novel therapeutic for inflammatory bowel disease.

Whole-transcriptome analysis of periodontal tissue and construction of immune-related competitive endogenous RNA network.

BACKGROUND: In periodontitis, noncoding RNAs may play a regulatory role in the immune microenvironment through competitive endogenous RNA. We aimed to profile noncoding RNA expression and construct immune-related ceRNA network in periodontitis. METHODS: Five inflamed periodontal tissue and five healthy gingivae were collected for whole-transcriptome sequencing. Differential gene, functional enrichment, and protein-protein interaction network analysis were performed to explore the function of differentially expressed genes. CIBERSORTx was used to analyze level of immune cell infiltration in the periodontal tissue. An immune-related competitive endogenous RNA network was constructed and expression of key regulators in the network was validated. RESULTS: Compared with healthy gingiva, 200 mRNAs, 90 long noncoding RNAs, 65 microRNAs, and 518 circular RNAs were differentially expressed, and cell chemotaxis was significantly enhanced in inflamed periodontal tissue. Immune cell infiltration analysis showed that neutrophils, macrophages M1, T follicular helper cells, and naive B cells were significantly increased in periodontitis. Key regulators including JUN, FOS, THBS1, KLF2, WIF1, were identified and their expression was then validated. CONCLUSION: We constructed an immune-related competitive endogenous RNA network in periodontal tissue, which provided new insights into immune homeostasis in periodontitis and laid a foundation for further study of noncoding RNAs. Key regulators in this network may be promising targets for future periodontitis treatment.

microRNA-144/451 decreases dendritic cell bioactivity via targeting interferon-regulatory factor 5 to limit DSS-induced colitis.

The microRNAs miR-144/451 are highly conserved miRNA that is strongly induced during erythropoiesis. Despite the biological functions of miR-144/451 have been extensively studied in erythropoiesis and tumorigenesis, few studies have been conducted in immune responses. In this study, we showed that miR-144/451-/- DCs exhibit increased activation. Mechanistically, the miR-144 directly targets the 3`-UTR of IRF5 and represses the expression of IRF5 in DCs. Ectopic expression of miR-144/451 by lentiviruses downregulates the levels of IRF5 and suppresses DCs function. In addition, knockdown of IRF5 by shRNA significantly inhibits activities of the miR-144/451-/- DCs. Expression of miR144/451 was decreased in DCs from both patients with IBD and mice with DSS-colitis compared with controls. Human PBMC derived DCs were downregulated expression of miR144/451 after LPS stimulation. In the DSS-induced colitis mice model, we showed that ablation of the miR-144/451 gene causes severe colitis, and their DCs from both periphery and MLN expressed higher co-stimulatory molecules and pro-inflammatory cytokines than wild-type mice. In addition, DCs isolated from miR-144/451-/- mice transfusion exacerbates mice colitis. In the bone marrow transplanted chimeric mice model, we show that miR-144/451-/- bone marrow transplantation deteriorated DSS-induced colitis. At last, we treat the mice with miR-144/451 delivered by chitosan nanoparticles revealing protective effects in DSS-induced colitis mice. Thus, our results reveal a novel miR144/451-IRF5 pathway in DCs that protects experimental colitis. The manipulation of miR-144/451 expression and DCs activation in IBD patients may be a novel therapeutic approach for the treatment of inflammatory diseases.

miR-99a-5p: A Potential New Therapy for Atherosclerosis by Targeting mTOR and Then Inhibiting NLRP3 Inflammasome Activation and Promoting Macrophage Autophagy.

Objective: MicroRNAs have been revealed to be involved in the development of atherosclerosis. The present study is aimed at exploring the potential of miR-99a-5p as a therapy for atherosclerosis. We suspected that miR-99a-5p might inhibit NLRP3 inflammasome activation and promote macrophage autophagy via constraining mTOR, therefore, alleviating atherosclerosis. Methods: The cell viability in ox-LDL-induced THP-1 macrophages was assessed by CCK-8 assay. Bioinformatic analysis was used to predict the target genes of miR-99a-5p. The binding between miR-99a-5p and mTOR was confirmed by luciferase reporter assay. In vivo, a high-fat-diet-induced atherosclerosis model was established in apolipoprotein E knockout mice. Hematoxylin-eosin, oil red O, and Sirius red staining were performed for the determination of atherosclerotic lesions. MTOR and associated protein levels were detected by Western blot analysis. Results: miR-99a-5p inhibited NLRP3 inflammasome activation and promoted macrophage autophagy by targeting mTOR. Enforced miR-99a-5p significantly reduced the levels of inflammasome complex and inflammatory cytokines. Furthermore, miR-99a-5p overexpression inhibited the expression of mTOR, whereas mTOR overexpression reversed the trend of the above behaviors. In vivo, the specific overexpression of miR-99a-5p significantly reduced atherosclerotic lesions, accompanied by a significant downregulation of autophagy marker CD68 protein expression. Conclusion: We demonstrated for the first time that miR-99a-5p may be considered a therapy for atherosclerosis. The present study has revealed that miR-99a-5p might inhibit NLRP3 inflammasome activation and promote macrophage autophagy by targeting mTOR, therefore, alleviating atherosclerosis.

Immune regulatory effects of microRNA9-3.

MicroRNAs are known to regulate cell proliferation, differentiation, and apoptosis. However, the immunological mechanism and role of microRNA9-3 (miR9-3) are unknown. This study used CRISPR/cas9 technology to knock out miR9-3 to modulate its expression level. FACS results showed that the absolute number of total B cells declined in miR9-3-deficiency in the spleen (Sp), bone marrow (BM), and lymph node (LN) to different levels compared to the wild-type. Also, the absolute numbers of Fo, T1, and T2 cells decreased both in Sp and LN. The absolute numbers of total T cells in Sp and LN declined sharply; CD4+ and CD8+ T cells showed a dramatic decrease in Sp, LN, and Th (thymus) of the miR9-3- group. In BM, the cells number of immature B cells, pro-pre-B cells, pro-B cells, and pre-B cells reduced to different levels, while mature B cells were comparable to wild-type. These data illustrated that miR9-3-deficiency impaired the development of B cells in BM. Also, the development of T cells was severely impaired. In Th, the numbers of DN and DP cells were remarkably reduced in the miR9-3 mutant mice. Also, the numbers of DN-1, DN-3, and DN-4 cells decreased. The absolute number of cells in the hematopoietic stem cell (HSC) system such as LT-HSC (long-term HSC), ST-HSC (short-term HSC), MPP (multipotent progenitor), GMP (granulocyte-macrophage progenitor), CMP (common myeloid progenitors), MEP (megakaryocyte-erythroid progenitor), and CLP (common lymphoid progenitor) all were decreased in miR9-3 deficient mice. These results showed that miR9-3 deficiency initiated the damage to the entire hematopoietic system. Moreover, the absolute number of myeloid cells in both Sp and BM decreased in mutant mice. The cells number of NK cells showed a sharp reduction in Sp whereas the change was not significant in BM. The above results suggest that miR9-3 participates in the immune regulation of B cells, T cells, and the HSC system, highlighting its regulatory roles.

Inhibition of miR-let-7i Induces DC Immature Cells and Improves Skin Graft Tolerance.

Dendritic cells (DC) initiate the immune response in the body. They can stimulate T cell activation, proliferation, and differentiation and ultimately participate in the immune response and the immune tolerance response. The purpose of this study was to coculture DCs and T cells and subcutaneously inject DCs transfected with miR-let-7i into rhesus monkey transplantations to verify the role of miR-let-7i in allograft immune tolerance. In vitro studies found that the expression of miR-let-7i was upregulated after inducing the maturation of DCs. The low expression of miR-let-7i inhibited the maturation of DCs, promoted the differentiation of T cells into T helper T cells 2 (Th2), and inhibited T helper T cell 1- (Th1-) driven rejection. In vivo studies also obtained similar results, and subcutaneous injection of DCs transfected with miR-let-7i inhibitor prolonged the survival time of allogeneic skin transplantation. Therefore, we conclude that inhibition of miR-let-7i inhibits DC maturation and improves the tolerance of grafted skin.

microRNA-4701-5p protects against interleukin-1ß induced human chondrocyte CHON-001 cells injury via modulating HMGA1.

BACKGROUND: miRNA-4701-5p has been reported to be a vital regulator in many diseases, including rheumatoid arthritis, and miRNA-4701-5p is evidenced to be participated in synovial invasion and joint destruction. In our report, we investigated the roles of miRNA-4701-5p in osteoarthritis (OA) and analyzed the molecular mechanism. METHODS: Interleukin-1ß (IL-1ß) was applied for stimulating human chondrocyte CHON-001 cells to establish an OA injury model. mRNA levels and protein expression were measured using qRT-PCR and western blot assay, respectively. The proliferation ability and cytotoxicity of CHON-001 cells were checked using MTT assay and lactate dehydrogenase activity. The inflammation of chondrocytes was accessed by the secretion levels of interleukin-6 (IL-6), interleukin-8 (IL-8) and tumor necrosis factor (TNF)-α. The apoptosis of chondrocytes was determined by flow cytometry assay. Bioinformatics software Starbase v2.0 analyzed the functional binding sites between miRNA-4701-5p and HMGA1 and the interaction was further confirmed using dual luciferase reporter analysis. RESULTS: miRNA-4701-5p was down-regulated in the IL-1ß-stimulated chondrocytes and HMGA1 directly targeted miRNA-4701-5p. Up-regulation of miRNA-4701-5p could alleviate IL-1ß-treated CHON-001 cells inflammation and apoptosis, and reversed the cell proliferation decrease and cytotoxicity increase after IL-1ß treatment. Nevertheless, all the roles of miRNA-4701-5p overexpression in CHON-001 cells could be reversed by HMGA1 up-regulation. CONCLUSIONS: miRNA-4701-5p could alleviate the inflammatory injury of IL-1ß-treated CHON-001 cells via down-regulating HMGA1, indicating that miRNA-4701-5p/HMGA1 is a promising therapeutic target for OA.

The correlation of lncRNA SNHG16 with inflammatory cytokines, adhesion molecules, disease severity, and prognosis in acute ischemic stroke patients.

BACKGROUND: Long non-coding RNA small nucleolar RNA host gene 16 (lncRNA SNHG16) is involved in the pathogenesis of acute ischemic stroke (AIS) through the regulation of brain endothelial cell viability, inflammation, atherosclerotic plaque formation, and neural apoptosis. This study aimed to evaluate the prognostic value of lncRNA SNHG16 in AIS patients. METHODS: Newly diagnosed AIS patients (N = 120) were serially recruited. Their lncRNA SNHG16 expressions in peripheral blood mononuclear cells (PBMCs) were detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR); serum inflammatory cytokines and adhesion molecules were determined using enzyme-linked immunosorbent assay (ELISA). The accumulating recurrence-free survival (RFS) and overall survival (OS) were analyzed. Moreover, controls (N = 60) were recruited and their lncRNA SNHG16 expressions in PBMCs were detected. RESULTS: LncRNA SNHG16 was declined in AIS patients compared to controls (p < 0.001). Moreover, lncRNA SNHG16 was not related to any comorbidities in AIS patients (all p > 0.05). Interestingly, lncRNA SNHG16 was negatively related to tumor necrosis factor alpha (TNF-α) (p < 0.001), interleukin 6 (IL-6) (p = 0.013), and intracellular cell adhesion molecule-1 (ICAM-1) (p = 0.024), while positively correlated with interleukin 10 (IL-10) (p = 0.022) in AIS patients. Besides, lncRNA SNHG16 was inversely associated with the National Institutes of Health Stroke Scale (NIHSS) score in AIS patients (p = 0.003). During the follow-up period, in 14 (11.7%) patients occurred recurrence and 5 (4.2%) patients died. Unexpectedly, lncRNA SNHG16 was not associated with accumulating RFS (p = 0.103) or OS (p = 0.150) in AIS patients. CONCLUSION: LncRNA SNHG16 relates to lower inflammatory cytokines, adhesion molecules, and milder disease severity, but fails to predict prognosis in AIS patients.

Cutting Edge: Enhanced Antitumor Immunity in ST8Sia6 Knockout Mice.

Inhibitory receptors have a critical role in the regulation of immunity. Siglecs are a family of primarily inhibitory receptors expressed by immune cells that recognize specific sialic acid modifications on cell surface glycans. Many tumors have increased sialic acid incorporation. Overexpression of the sialyltransferase ST8Sia6 on tumors led to altered immune responses and increased tumor growth. In this study, we examined the role of ST8Sia6 on immune cells in regulating antitumor immunity. ST8Sia6 knockout mice had an enhanced immune response to tumors. The loss of ST8Sia6 promoted an enhanced intratumoral activation of macrophages and dendritic cells, including upregulation of CD40. Intratumoral regulatory T cells exhibited a more inflammatory phenotype in ST8Sia6 knockout mice. Using adoptive transfer studies, the change in regulatory T cell phenotype was not cell intrinsic and depended on the loss of ST8Sia6 expression in APCs. Thus, ST8Sia6 generates ligands for Siglecs that dampen antitumor immunity.

Host Cells Actively Resist Porcine Reproductive and Respiratory Syndrome Virus Infection via the IRF8-MicroRNA-10a-SRP14 Regulatory Pathway.

MicroRNAs (miRNAs) play an important role in the virus-host interaction. Our previous work has indicated that the expression level of miR-10a increased in porcine alveolar macrophages (PAMs) during porcine reproductive and respiratory syndrome virus (PRRSV) infection and further inhibited viral replication through downregulates the expression of host molecule signal-recognition particle 14 (SRP14) protein. However, the molecular mechanism of miR-10a increased after PRRSV infection remains unknown. In the present study, transcription factor interferon regulatory factor 8 (IRF8) was identified as a negative regulator of miR-10a. PRRSV infection decreases the expression level of IRF8 in PAMs, leading to upregulating miR-10a expression to play an anti-PRRSV role. Meanwhile, this work first proved that IRF8 promoted PRRSV replication in an miR-10a-dependent manner. Further, we explained that SRP14, the target gene of miR-10a, promotes the synthesis of the PRRSV genome by interacting with the viral components Nsp2, thus facilitating PRRSV replication. In conclusion, we identified a novel IRF8-miR-10a-SRP14 regulatory pathway against PRRSV infection, which provides new insights into virus-host interactions and suggests potential new antiviral strategies to control PRRSV. IMPORTANCE Porcine reproductive and respiratory syndrome virus (PRRSV) has rapidly spread to the global pig industry and caused incalculable economic damage since first discovered in the 1980s. However, conventional vaccines do not provide satisfactory protection. Understanding the molecular mechanisms of host resistance to PRRSV infection is necessary to develop safe and effective strategies to control PRRSV. During viral infection, miRNAs play vital roles in regulating the expression of viral or host genes at the posttranscriptional level. The significance of our study is that we revealed the transcriptional regulation mechanism of the antiviral molecule miR-10a after PRRSV infection. Moreover, our research also explained the mechanism of host molecule SRP14, the target gene of miR-10a regulating PRRSV replication. Thus, we report a novel regulatory pathway of IRF8-miR-10a-SRP14 against PRRSV infection, which provides new insights into virus-host interactions and suggests potential new control measures for future PRRSV outbreaks.

microRNA-142 guards against autoimmunity by controlling Treg cell homeostasis and function.

Regulatory T (Treg) cells are critical in preventing aberrant immune responses. Posttranscriptional control of gene expression by microRNA (miRNA) has recently emerged as an essential genetic element for Treg cell function. Here, we report that mice with Treg cell-specific ablation of miR-142 (hereafter Foxp3CremiR-142fl/fl mice) developed a fatal systemic autoimmune disorder due to a breakdown in peripheral T-cell tolerance. Foxp3CremiR-142fl/fl mice displayed a significant decrease in the abundance and suppressive capacity of Treg cells. Expression profiling of miR-142-deficient Treg cells revealed an up-regulation of multiple genes in the interferon gamma (IFNγ) signaling network. We identified several of these IFNγ-associated genes as direct miR-142-3p targets and observed excessive IFNγ production and signaling in miR-142-deficient Treg cells. Ifng ablation rescued the Treg cell homeostatic defect and alleviated development of autoimmunity in Foxp3CremiR-142fl/fl mice. Thus, our findings implicate miR-142 as an indispensable regulator of Treg cell homeostasis that exerts its function by attenuating IFNγ responses.