LincRNA-Cox2 Regulates Smoke-induced Inflammation in Murine Macrophages

Cigarette smoke (CS) exposure is a risk factor for many chronic diseases, including chronic obstructive pulmonary disease, but the mechanism by which smoke exposure can alter homeostasis and bring about chronic inflammation is poorly understood. Here, we showcase a novel role for smoke in regulating long noncoding RNAs, showing that it activates lincRNA-Cox2, which we previously characterized as functional in inflammatory regulation. Exposing lincRNA-Cox2 murine models to smoke in vivo confirmed lincRNA-Cox2 as a regulator of inflammatory gene expression in response to smoke both systemically and within the lung. We also report that lincRNA-Cox2 negatively regulates genes in smoked bone marrow-derived macrophages exposed to LPS stimulation. In addition to the effects on long noncoding RNAs, we also report dysregulated transcription and splicing of inflammatory protein-coding genes in the bone marrow niche after CS exposure in vivo. Collectively, this work provides insights into how innate immune signaling from gene expression to splicing is altered after in vivo exposure to CS and highlights an important new role for lincRNA-Cox2 in regulating immune genes after smoke exposure.

Inhibition of lincRNA-Cox2 alleviates apoptosis and inflammatory injury of lipopolysaccharide-stimulated human bronchial epithelial cells via the Nrf2/HO-1 axis

This study mainly explored the role and mechanism of lincRNA-Cox2 in inflammatory injury of human bronchial epithelial cells. BEAS-2B cells were stimulated with lipopolysaccharide to establish an in vitro inflammatory injury model. Real-time polymerase chain reaction was used to detect lincRNA-Cox2 expression in LPS-stimulated BEAS-2B. Cell viability and apoptosis of cells were assessed using CCK-8 and Annexin V-PI double staining. The contents of inflammatory factors were determined by enzyme-linked immunosorbent assay kits. The protein levels of nuclear factor erythrocyte 2-related factor 2 and haem oxygenase 1 protein levels were measured by Western blot. The results showed that lincRNA-Cox2 was upregulated in LPS-stimulated BEAS-2B cells. lincRNA-Cox2 knockdown inhibited apoptosis and the release of tumour necrosis factor alpha, interleukin 1beta (IL-1β), IL-4, IL-5, and IL-13 in BEAS-2B cells. lincRNA-Cox2 overexpression had the opposite effect. lincRNA-Cox2 knockdown also inhibited LPS-induced oxidative damage in BEAS-2B cells. Further mechanistic studies showed that inhibition of lincRNA-Cox2 upregulated the levels of Nrf2 and HO-1, and si-Nrf2 reversed the effects of si-lincRNA-Cox2. In conclusion, lincRNA-Cox2 knockdown inhibited BEAS-2B apoptosis and the level of inflammatory factors by activating the Nrf2/HO-1 pathway.

Altered Lnc-EGFR, SNHG1, and LincRNA-Cox2 Profiles in Patients with Relapsing-Remitting Multiple Sclerosis: Impact on Disease Activity and Progression

Relapsing-remitting multiple sclerosis (RRMS) is the most prevalent MS subtype. Ample evidence has indicated that long noncoding RNAs (lncRNAs) are crucial players in autoimmune and inflammatory disorders. This study investigated the expression of lnc-EGFR, SNHG1, and lincRNA-Cox2 in RRMS patients during active relapses and in remission. Additionally, the expression of FOXP3, a master transcription factor for regulatory T cells, and NLRP3-inflammasome-related genes were determined. Relationships between these parameters and MS activity and annualized relapse rate (ARR) were also evaluated. The study included 100 Egyptian participants: 70 RRMS patients (35 during relapse and 35 in remission) and 30 healthy controls. RRMS patients showed significant downregulation of lnc-EGFR and FOXP3 and dramatic upregulation of SNHG1, lincRNA-Cox2, NLRP3, ASC, and caspase-1 compared to controls. Lower serum TGF-β1 and elevated IL-1β levels were observed in RRMS patients. Notably, patients during relapses displayed more significant alterations than those in remission. Lnc-EGFR was positively correlated with FOXP3 and TGF-β1 and negatively correlated with ARR, SNHG1, lincRNA-Cox2, and NLRP3 inflammasome components. Meanwhile, SNHG1 and lincRNA-Cox2 were positively correlated with ARR, NLRP3, ASC, caspase-1, and IL-1β. Excellent diagnostic performance for lnc-EGFR, FOXP3, and TGF-β1 was demonstrated, while all biomarkers exhibited strong prognostic potential for predicting relapses. Finally, the differential expression of lnc-EGFR, SNHG1, and lincRNA-Cox2 in RRMS patients, especially during relapses, suggests their involvement in RRMS pathogenesis and activity. Correlation between their expression and ARR implies relationships to disease progression. Our findings also highlight their promising roles as biomarkers for RRMS.

LincRNA-Cox2 regulates IL6/JAK3/STAT3 and NF-κB P65 pathway activation in Listeria monocytogenes-infected RAW264.7 cells

Listeria monocytogenes (Lm) can lead to high mortality rates relative to other foodborne pathogens. Lm-induced inflammation is partly characterized by macrophage activation. Long non-coding RNAs (lncRNAs) have important roles in various biological processes. However, it is unknown how lncRNAs regulate the host response to Lm infection. To identify the role of lncRNA in Lm infection, we used in vitro and in vivo models. We found that lincRNA-Cox2 was highly expressed in Lm-infected RAW264.7 cells. LincRNA-Cox2 knockdown resulted in reduced proinflammatory cytokines, apoptosis, migration ability and enhanced phagocytosis of Lm. LincRNA-Cox2 knockdown also reduced the phosphorylation of Janus kinase 3 (JAK3) and signal transducer and activator of transcription (STAT3) and the nuclear translocation of nuclear factor (NF)-κB P65, which are known to be involved in inflammatory responses. Experimentally inhibiting the protein and phosphorylation levels of STAT3 resulted in reduced proinflammatory cytokines and enhanced phagocytosis of Lm by the RAW264.7 cells. Our research suggests that lincRNA-Cox2 plays important roles in inflammation, the phagocytic function and cell migration ability of RAW264.7 cells by activating interleukin (IL)-6/JAK3/STAT3 signaling, and lincRNA-Cox2 also regulates NF-κB P65 nuclear translocation. Our research provides new insights into the regulatory role of lincRNA-Cox2 in Lm infection.

Role of lincRNA-Cox2 targeting miR-150 in regulating the viability of chondrocytes in osteoarthritis

Osteoarthritis (OA) is a joint disease characterised by progressive cartilage degradation and inflammation, but the detailed pathogenesis of OA remains unclear. The present study aimed to investigate the role of long intergenic non-coding RNA (lincRNA)-Cox2 in OA progression and the potential mechanism. An OA mouse model was used for in vivo experiments, and IL-1β-induced injury of mouse chondrocytes was conducted for in vitro experiments. Small interfering (si)-Cox2 was transfected into chondrocytes to elucidate the effect of lincRNA-Cox2 on OA. Quantitative reverse transcription PCR assays were conducted to detect the expression of lincRNA-Cox2 and microRNA (miR)-150. Cell proliferation and apoptosis were analysed based on an MTT assay and annexin V/propidium iodide staining, respectively. Western blotting was performed to evaluate the protein expression levels of Ki-67, PCNA, Bax, cleaved (c)-Caspase-3, c-Caspase-9 and Wnt/β-catenin pathway-associated proteins in chondrocytes. High levels of lincRNA-Cox2 were observed in cartilage tissues of the OA mouse model in vivo. In the in vitro experiments, the expression of lincRNA-Cox2 was increased in IL-1β-treated chondrocytes. Knockdown of lincRNA-Cox2 promoted the proliferation and inhibited the apoptosis of chondrocytes. Mechanistically, lincRNA-Cox2 was found to directly target miR-150, acting as a competing endogenous RNA, and the effect of si-Cox2 on the proliferation and apoptosis of chondrocytes was reversed by miR-150 inhibitors. Moreover, lincRNA-Cox2 activated the Wnt/β-catenin pathway to regulate chondrocyte proliferation and apoptosis. The present study demonstrated that silencing lincRNA-Cox2 expression plays a protective role in OA by enhancing the proliferation and suppressing the apoptosis of chondrocytes, which is related to increased miR-150 expression and activation of the Wnt/β-catenin pathway.

Intranasal Delivery of lincRNA-Cox2 siRNA Loaded Extracellular Vesicles Decreases Lipopolysaccharide-Induced Microglial Proliferation in Mice

Long non-coding RNAs (lncRNAs), including long intergenic non-coding RNAs (lincRNAs), play an important regulatory role in controlling various biological processes. Both in vitro and in vivo studies have demonstrated that lincRNA-Cox2 plays a global regulatory role in regulating the expression of immune genes. Extracellular vesicles (EVs) are cell-derived nanosized membrane vesicles that have gained increasing attention in recent years due to their ability to efficiently deliver therapeutics to specific target organs or cell types. In this study, we found that lincRNA-Cox2 controls the expression of a set of cell cycle genes in lipopolysaccharide (LPS)-stimulated microglial cells. Our in vitro study suggested that knocking down lincRNA-Cox2 reversed LPS-induced microglial proliferation. In addition, our in vivo study demonstrated that intranasally delivered lincRNA-Cox2-siRNA loaded EVs could reach the brain resulting in a significant decrease in the expression of lincRNA-Cox2 in the microglia. Importantly, lincRNA-Cox2-siRNA loaded EVs also decreased LPS-induced microglial proliferation in mice. These findings indicate that intranasal delivery of EV-loaded small RNA could be developed as therapeutics for treatment of a multitude of CNS disorders.

Genetic Models Reveal cis and trans Immune-Regulatory Activities for lincRNA-Cox2

An inducible gene expression program is a hallmark of the host inflammatory response. Recently, long intergenic non-coding RNAs (lincRNAs) have been shown to regulate the magnitude, duration, and resolution of these responses. Among these is lincRNA-Cox2, a dynamically regulated gene that broadly controls immune gene expression. To evaluate the in vivo functions of this lincRNA, we characterized multiple models of lincRNA-Cox2-deficient mice. LincRNA-Cox2-deficient macrophages and murine tissues had altered expression of inflammatory genes. Transcriptomic studies from various tissues revealed that deletion of the lincRNA-Cox2 locus also strongly impaired the basal and inducible expression of the neighboring gene prostaglandin-endoperoxide synthase (Ptgs2), encoding cyclooxygenase-2, a key enzyme in the prostaglandin biosynthesis pathway. By utilizing different genetic manipulations in vitro and in vivo, we found that lincRNA-Cox2 functions through an enhancer RNA mechanism to regulate Ptgs2. More importantly, lincRNA-Cox2 also functions in trans, independently of Ptgs2, to regulate critical innate immune genes in vivo.