The role of long non-coding RNAs in rheumatic diseases

Long non-coding RNAs as pathophysiological regulators, therapeutic targets and novel extracellular vesicle biomarkers for the diagnosis of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic relapsing disease of the gastrointestinal (GI) system that includes two groups, Crohn's disease (CD) and ulcerative colitis (UC). To cope with these two classes of IBD, the investigation of pathogenic mechanisms and the discovery of new diagnostic and therapeutic approaches are crucial. Long non-coding RNAs (lncRNAs) which are non-coding RNAs with a length of longer than 200 nucleotides have indicated significant association with the pathology of IBD and strong potential to be used as accurate biomarkers in diagnosing and predicting responses to the IBD treatment. In the current review, we aim to investigate the role of lncRNAs in the pathology and development of IBD. We first describe recent advances in research on dysregulated lncRNAs in the pathogenesis of IBD from the perspective of epithelial barrier function, intestinal immunity, mitochondrial function, and intestinal autophagy. Then, we highlight the possible translational role of lncRNAs as therapeutic targets, diagnostic biomarkers, and predictors of therapeutic response in colon tissues and plasma samples. Finally, we discuss the potential of extracellular vesicles and their lncRNA cargo in the pathophysiology, diagnosis, and treatment of IBD.

Long Non-Coding RNAs in Sjögren's Disease

Sjögren's disease (SjD) is a heterogeneous autoimmune disease characterized by severe dryness of mucosal surfaces, particularly the mouth and eyes; fatigue; and chronic pain. Chronic inflammation of the salivary and lacrimal glands, auto-antibody formation, and extra-glandular manifestations occur in subsets of patients with SjD. An aberrant expression of long, non-coding RNAs (lncRNAs) has been described in many autoimmune diseases, including SjD. Here, we review the current literature on lncRNAs in SjD and their role in regulating X chromosome inactivation, immune modulatory functions, and their potential as biomarkers.

Integrated analysis of m6A regulator-mediated RNA methylation modification patterns and immune characteristics in Sjögren's syndrome

The epigenetic modifier N6-methyladenosine (m6A), recognized as the most prevalent internal modification in messenger RNA (mRNA), has recently emerged as a pivotal player in immune regulation. Its dysregulation has been implicated in the pathogenesis of various autoimmune conditions. However, the implications of m6A modification within the immune microenvironment of Sjögren's syndrome (SS), a chronic autoimmune disorder characterized by exocrine gland dysfunction, remain unexplored. Herein, we leverage an integrative analysis combining public database resources and novel sequencing data to investigate the expression profiles of m6A regulatory genes in SS. Our cohort comprised 220 patients diagnosed with SS and 62 healthy individuals, enabling a comprehensive evaluation of peripheral blood at the transcriptomic level. We report a significant association between SS and altered expression of key m6A regulators, with these changes closely tied to the activation of CD4+ T cells. Employing a random forest (RF) algorithm, we identified crucial genes contributing to the disease phenotype, which facilitated the development of a robust diagnostic model via multivariate logistic regression analysis. Further, unsupervised clustering revealed two distinct m6A modification patterns, which were significantly associated with variations in immunocyte infiltration, immune response activity, and biological function enrichment in SS. Subsequently, we proceeded with a screening process aimed at identifying genes that were differentially expressed (DEGs) between the two groups distinguished by m6A modification. Leveraging these DEGs, we employed weight gene co-expression network analysis (WGCNA) to uncover sets of genes that exhibited strong co-variance and hub genes that were closely linked to m6A modification. Through rigorous analysis, we identified three critical m6A regulators - METTL3, ALKBH5, and YTHDF1 - alongside two m6A-related hub genes, COMMD8 and SRP9. These elements collectively underscore a complex but discernible pattern of m6A modification that appears to be integrally linked with SS's pathogenesis. Our findings not only illuminate the significant correlation between m6A modification and the immune microenvironment in SS but also lay the groundwork for a deeper understanding of m6A regulatory mechanisms. More importantly, the identification of these key regulators and hub genes opens new avenues for the diagnosis and treatment of SS, presenting potential targets for therapeutic intervention.

Novel potential lncRNA biomarker in B cells indicates essential pathogenic pathway activation in patients with SLE

OBJECTIVES

Systemic lupus erythematosus (SLE) is a highly heterogeneous disease, and B cell abnormalities play a central role in the pathogenesis of SLE. Long non-coding RNAs (lncRNAs) have also been implicated in the pathogenesis of SLE. The expression of lncRNAs is finely regulated and cell-type dependent, so we aimed to identify B cell-expressing lncRNAs as biomarkers for SLE, and to explore their ability to reflect the status of SLE critical pathway and disease activity.

METHODS

Weighted gene coexpression network analysis (WGCNA) was used to cluster B cell-expressing genes of patients with SLE into different gene modules and relate them to clinical features. Based on the results of WGCNA, candidate lncRNA levels were further explored in public bulk and single-cell RNA-sequencing data. In another independent cohort, the levels of the candidate were detected by RT-qPCR and the correlation with disease activity was analysed.

RESULTS

WGCNA analysis revealed one gene module significantly correlated with clinical features, which was enriched in type I interferon (IFN) pathway. Among non-coding genes in this module, lncRNA RP11-273G15.2 was differentially expressed in all five subsets of B cells from patients with SLE compared with healthy controls and other autoimmune diseases. RT-qPCR validated that RP11-273G15.2 was highly expressed in SLE B cells and positively correlated with IFN scores (r=0.7329, p<0.0001) and disease activity (r=0.4710, p=0.0005).

CONCLUSION

RP11-273G15.2 could act as a diagnostic and disease activity monitoring biomarker for SLE, which might have the potential to guide clinical management.

Epigenetic Dysregulation in the Pathogenesis of Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease in which immune disorders lead to autoreactive immune responses and cause inflammation and tissue damage. Genetic and environmental factors have been shown to trigger SLE. Recent evidence has also demonstrated that epigenetic factors contribute to the pathogenesis of SLE. Epigenetic mechanisms play an important role in modulating the chromatin structure and regulating gene transcription. Dysregulated epigenetic changes can alter gene expression and impair cellular functions in immune cells, resulting in autoreactive immune responses. Therefore, elucidating the dysregulated epigenetic mechanisms in the immune system is crucial for understanding the pathogenesis of SLE. In this paper, we review the important roles of epigenetic disorders in the pathogenesis of SLE.

CYP51-mediated cholesterol biosynthesis is required for the proliferation of CD4+ T cells in Sjogren's syndrome

CYtochrome P450, family 51 (CYP51) is an important enzyme for de novo cholesterol synthesis in mammalian cells. In the present study, we found that the expression of CYP51 positively correlated with CD4+ T cell activation both in vivo and in vitro. The addition of ketoconazole, a pharmacological inhibitor of CYP51, prevented the proliferation and activation of anti-CD3/CD28-expanded mouse CD4+ T cells in a dose-dependent fashion. Liquid chromatography-tandem mass spectrometry indicated an increase in levels of lanosterol in T cells treated with ketoconazole during activation. Ketoconazole-induced blockade of the cholesterol synthesis pathway also caused Sterol regulatory element binding protein 2 (SREBP2) activation in CD4+ T cells. Additionally, ketoconazole treatment elicited an integrated stress response in T cells that up-regulated activating transcription factor 4 (ATF4) and DNA-damage inducible transcript 3 (DDIT3/CHOP) at the translational level. Furthermore, treatment with ketoconazole significantly decreased the amount of CD4+ T cells infiltrating lesions in the submandibular glands of NOD/Ltj mice. In summary, our results suggest that CYP51 plays an essential role in the proliferation and survival of CD4+ T cells, which makes ketoconazole an inhibitor of CD4+ T cell proliferation and of the SS-like autoimmune response through regulating the biosynthesis of cholesterol and inducing the integrated stress response.

Expression patterns of T cells-specific long noncoding RNAs in systemic lupus erythematosus patients carrying HLA risk/nonrisk alleles

BACKGROUND

Long noncoding RNAs (LncRNAs) play key roles in the regulation of gene expression and subsequently in the pathogenesis of several autoimmune diseases. This study aimed to explore the peripheral expression levels of T-cells-specific LncRNAs and transcription factors in systemic lupus erythematosus (SLE) patients carrying either human leukocyte antigens (HLA) risk or non-risk alleles.

METHODS

Genotypes of HLA-DRB1 and HLA-DQB1 loci for 106 SLE patients were determined by PCR-SSP. In the next step, patients were stratified based on the presence of HLA-DRB1*03 and/or DRB1*16 allele groups (HLA risk alleles positive or HLA-RPos) or carrying other DRB1 allele groups (HLA-RNeg). Then, transcript levels of LncRNAs (IFNG-AS1, RMRP, Th2LCR, and DQ786243) and mRNAs for transcription factors (Foxp3, Gata3, and Tbx21) were measured using qRT-PCR and compared between two subgroups of patients.

RESULTS

Totally, 47 cases were classified as HLA-RPos and 59 cases as HLA-RNeg patients. The HLA-RPos patients showed decreased transcript levels of DQ786243 (p = .001) and elevated expression of IFNG-AS1 (p = .06) and T-bet mRNA (p = .03) compared to the HLA-RNeg group. We observed significantly lower expression of Th2LCR (p < .0001) and DQ786243 (p = .001) and higher expression of Tbx21 (p = .009) and Foxp3 (p = .02) in DR3-positive versus DR3-negative patients. Likewise, decreased transcript levels of DQ786243 (p = .02) and RMRP (p = .003) were observed in DR16-positive versus DR16-negative patients. ROC curve analysis revealed the potential of DQ786243 and RMRP as biomarkers in SLE disease based on the carriage of HLA risk alleles.

CONCLUSIONS

Our results indicate that the contribution of multiple T cell subsets in SLE disease progression as judged by expression analysis of LncRNAs and transcription factors can be inspired by the inheritance of HLA risk/nonrisk alleles is SLE patients.

LncRNA SELL/L-selectin Promotes HPV-Positive HNSCC Progression and Drives Fucoidan-Mediated Therapeutic Strategies

Positive human papillomavirus (HPV⁺) head and neck squamous cell carcinoma (HNSCC) presents a higher risk of lymph node metastasis and poor prognosis. Here, advanced microarray analysis of clinically collected HNSCC tissues revealed significant upregulation of the lncRNA SELL in HPV⁺ HNSCC, and its overexpression was obviously associated with lymph node metastasis. The lncRNA SELL could function as a promigratory and proinvasive mediator as well as an inducer of M1-like tumour-associated macrophages (TAM) by increasing the level of L-selectin. Furthermore, fucoidan, as an L-selectin inhibitor, obviously weakened the formation of tongue lesions induced by 4-Nitroquinoline N-oxide (4-NQO) in HPV16 E6/E7 transgenic mice. This result drove us to synchronously develop a nanodelivery platform to verify fucoidan-mediated anti-growth and anti-metastasis effects. This work highlighted the important influence of the lncRNA SELL/L-selectin on promoting HPV⁺ HNSCC progression and proposed a potential fucoidan-mediated therapeutic strategy. STATEMENT OF SIGNIFICANCE: Head and neck squamous cell carcinoma (HNSCC) patients with human papillomavirus (HPV) involvement present a greater risk of lymph node metastasis than HPV negative HNSCC patients. However, treatment protocols, including surgery and platinum-based chemo- and radiotherapy, have not improved the 5-year overall survival due to the high tendency of lymphatic metastasis. Here, microarray of clinical HNSCC samples confirms the oncogenic significance of lncRNA SELL, which acts as an M1-like TAM inducer and promotes tumorigenesis by upregulating L-selectin. Fucoidan, as an L-selectin inhibitor, suppresses tongue lesions in transgenic mice, and a fucoidan-mediated nanodelivery platform inhibits HPV⁺ HNSCC growth. The present study highlights lncRNA SELL/L-selectin on promoting HPV⁺ HNSCC progression and proposes a potential fucoidan-mediated therapeutic.

Plumbing mysterious RNAs in "dark genome" for the conquest of human diseases

Next-generation sequencing has revealed that less than 2% of transcribed genes are translated into proteins, with a large portion transcribed into noncoding RNAs (ncRNAs). Among these, long noncoding RNAs (lncRNAs) represent the largest group and are pervasively transcribed throughout the genome. Dysfunctions in lncRNAs have been found in various diseases, highlighting their potential as therapeutic, diagnostic, and prognostic targets. However, challenges, such as unknown molecular mechanisms and nonspecific immune responses, and issues of drug specificity and delivery present obstacles in translating lncRNAs into clinical applications. In this review, we summarize recent publications that have explored lncRNA functions in human diseases. We also discuss challenges and future directions for developing lncRNA treatments, aiming to bridge the gap between functional studies and clinical potential and inspire further exploration in the field.

Differential Expression of Non-Coding RNAs in Stem Cell Development and Therapeutics of Bone Disorders

Stem cells' self-renewal and multi-lineage differentiation are regulated by a complex network consisting of signaling factors, chromatin regulators, transcription factors, and non-coding RNAs (ncRNAs). Diverse role of ncRNAs in stem cell development and maintenance of bone homeostasis have been discovered recently. The ncRNAs, such as long non-coding RNAs, micro RNAs, circular RNAs, small interfering RNA, Piwi-interacting RNAs, etc., are not translated into proteins but act as essential epigenetic regulators in stem cells' self-renewal and differentiation. Different signaling pathways are monitored efficiently by the differential expression of ncRNAs, which function as regulatory elements in determining the fate of stem cells. In addition, several species of ncRNAs could serve as potential molecular biomarkers in early diagnosis of bone diseases, including osteoporosis, osteoarthritis, and bone cancers, ultimately leading to the development of new therapeutic strategies. This review aims to explore the specific roles of ncRNAs and their effective molecular mechanisms in the growth and development of stem cells, and in the regulation of osteoblast and osteoclast activities. Furthermore, we focus on and explore the association of altered ncRNA expression with stem cells and bone turnover.

SNP rs7130280 in lncRNA NONHSAT159216.1 confers susceptibility to Behçet's disease uveitis in a Chinese Han population

OBJECTIVE

Long noncoding RNA (lncRNA) plays a crucial role in the process of immune-mediated diseases. However, the defined involvement of lncRNA on Behçet's disease (BD) is not well known. The aim of this study was to investigate the effects of lncRNA-related single nucleotide polymorphisms (SNPs) on BD susceptibility in Chinese populations.

METHODS

A two-stage case-control association study was conducted in a cohort of 1152 BD individuals and 1152 healthy controls. Genotyping was performed by a MassARRAY System. Quantified expression of the lncRNA-miRNA-mRNA molecular axis was detected by real-time PCR and western blot. The cell proliferation was measured by CCK-8 assay.

RESULTS

Two-stage association analysis showed a significantly decreased frequency of A allele of SNP rs7130280 in BD patients compared with healthy controls [OR 0.72 (95% CI 0.64, 0.81), Pc = 1.15 × 10-6]. Functionally, SNP rs7130280 could influence the secondary structure and relative expression of NONHSAT159216.1 in human THP-1/U937 macrophages and in peripheral blood mononuclear cells from healthy volunteers. In vitro, overexpression of the rs7130280 A allele also suppressed cell proliferation. Mechanistically, rs7130280 A allele could inhibit the expression of miR-6778-5p, thus enhancing its downstream molecular RPS6KA4/IL10 in a competing endogenous RNA sponge manner.

CONCLUSION

Our findings suggest that NONHSAT159216.1 rs7130280 G>A might be associated with a low risk of BD and participates in a potential lncRNA-miRNA-mRNA regulatory network.

Crosstalk between lncRNAs in the apoptotic pathway and therapeutic targets in cancer

The assertion that a significant portion of the mammalian genome has not been translated and that non-coding RNA accounts for over half of polyadenylate RNA have received much attention. In recent years, increasing evidence proposes non-coding RNAs (ncRNAs) as new regulators of various cellular processes, including cancer progression and nerve damage. Apoptosis is a type of programmed cell death critical for homeostasis and tissue development. Cancer cells often have inhibited apoptotic pathways. It has recently been demonstrated that up/down-regulation of various lncRNAs in certain types of tumors shapes cancer cells' response to apoptotic stimuli. This review discusses the most recent studies on lncRNAs and apoptosis in healthy and cancer cells. In addition, the role of lncRNAs as novel targets for cancer therapy is reviewed here. Finally, since it has been shown that lncRNA expression is associated with specific types of cancer, the potential for using lncRNAs as biomarkers is also discussed.

Dysregulated pseudogene BNIP3P1 inhibited cell proliferation and promoted cell apoptosis in preeclampsia by acting as a competing endogenous RNA for BNIP3

Long noncoding RNAs (lncRNAs) have been reported as critical modulators in many diseases including preeclampsia. Since the association between lncRNA BNIP3P1 and its cognate gene BNIP3 in preeclampsia has been revealed previously, this study aimed to further explore the function and mechanism of BNIP3P1 in preeclampsia. EdU and TUNEL assays revealed that BNIP3P1 or BNIP3 overexpression inhibited trophoblast cell proliferation and enhanced cell apoptosis in preeclampsia. As suggested by western blot analysis, the protein levels of apoptotic markers in the cells were affected by BNIP3P1 or BNIP3 overexpression. The binding between miR-128-3p and BNIP3P1 (or BNIP3) was explored by luciferase reporter assays. Mechanistically, BNIP3P1 bound to miR-128-3p to upregulate BNIP3 expression by acting as a competing endogenous RNA (ceRNA). Importantly, BNIP3P1 was found to inactivate the mTOR signaling pathway. In conclusion, BNIP3P1 inhibited trophoblast cell proliferation and enhanced cell apoptosis in preeclampsia by targeting the miR-128-3p/BNIP3/mTOR signaling pathway.

Identification of molecular patterns and diagnostic biomarkers in juvenile idiopathic arthritis based on the gene expression of m6A regulators

The role of N ⁶-methyladenosine modification in immunity is increasingly being appreciated. However, the landscape of m⁶A regulators in juvenile idiopathic arthritis (JIA) is poorly understood. Thus, this study explored the impact of m⁶A modification and related lncRNAs in JIA immune microenvironment. Fourteen m⁶A regulators and eight lncRNAs were identified as potential diagnostic biomarkers for JIA. Two diagnostic models for JIA were also constructed. The putative molecular regulatory mechanism of FTO-mediated m⁶A modification in JIA was hypothesized. Three distinct m⁶A patterns mediated by 26 m⁶A regulators and three diverse lncRNA clusters mediated by 405 lncRNAs were thoroughly investigated. They exhibited dramatically diverse immune microenvironments and expression of HLA genes. The identification of two separate subtypes of enthesitis-related arthritis implies that our work may aid in the establishment of a more precise categorization system for JIA. m⁶A modification-related genes were obtained, and their underlying biological functions were explored. The m⁶Ascore system developed for individual JIA patients may be utilized to evaluate the immunological state or molecular pattern, thereby offering therapy recommendations. In short, through the investigation of the m⁶A regulators in JIA, the current work may contribute to our knowledge of the pathophysiology of JIA.

Comprehensive expression profiles of mRNAs, lncRNAs and miRNAs in Kashin-Beck disease identified by RNA-sequencing

Kashin-Beck disease (KBD) is a chronic, endemic and deforming osteochondropathy, whose basic pathological alterations include apoptosis and necrosis of chondrocytes in articular cartilage and growth plates and imbalanced extracellular matrix metabolism. Numerous studies have reported that long noncoding RNAs (lncRNAs) and microRNA (miRNAs) are aberrantly expressed in KBD. Our study was comprised of 5 KBD patients and 5 healthy individuals and we compared the expression profiles of mRNAs, lncRNAs and miRNAs through RNA-sequencing (RNA-seq). Bioinformatic analysis of GO and KEGG was employed to conduct functional annotation and pathway enriched analysis. In total, 3194 mRNAs, 4103 lncRNAs and 1550 miRNAs were detected to be differentially expressed by RNA-seq (P < 0.05; |log₂FC| ≥1). The lysosome pathway, Wnt signaling pathway, TNF signaling pathway, endocytosis and mTOR signaling pathway were identified to be involved in the KBD development according to the result of the KEGG analysis. In addition, a ceRNA network based on lncRNA-miRNA-mRNA was constructed to probe the intricate regulatory mechanism and interaction between transcripts, which was visualized using the Cytoscape software. The ce-lncRNAs of four aberrantly expressed genes, FOSB, EGR3, BCAM and SOX6, were determined through the network. Among the identified DElncRNAs, we selected 8 differentially expressed lncRNAs to confirm the reliability of RNA-seq data by qRT-PCR in 11 KBD patients and 11 healthy individuals. We aimed to provide a comprehensive understanding ofmRNA, lncRNA and miRNA alterations between KBD patients and healthy individuals, and meanwhile reveal several potential causative molecular and signaling pathways involved in KBD.

What do we know about the role of lncRNAs in multiple sclerosis?

Multiple sclerosis is a chronic, inflammatory and degenerative disease of the central nervous system of unknown aetiology although well-defined evidence supports an autoimmune pathogenesis. So far, the exact mechanisms leading to autoimmune diseases are still only partially understood. We know that genetic, epigenetic, molecular, and cellular factors resulting in pathogenic inflammatory responses are certainly involved. Long non-coding RNAs (lncRNAs) are non-protein coding transcripts longer than 200 nucleotides that play an important role in both innate and acquired immunity, so there is great interest in lncRNAs involved in autoimmune diseases. The research on multiple sclerosis has been enriched with many studies on the molecular role of lncRNAs in the pathogenesis of the disease and their potential application as diagnostic and prognostic biomarkers. In particular, many multiple sclerosis fields of research are based on the identification of lncRNAs as possible biomarkers able to predict the onset of the disease, its activity degree, its progression phase and the response to disease-modifying drugs. Last but not least, studies on lncRNAs can provide a new molecular target for new therapies, missing, so far, a cure for multiple sclerosis. While our knowledge on the role of lncRNA in multiple sclerosis has recently improved, further studies are required to better understand the specific role of lncRNAs in this neurological disease. In this review, we present the most recent studies on molecular characterization of lncRNAs in multiple sclerosis disorder discussing their clinical relevance as biomarkers for diagnosis and treatments.

LncRNA LINC00963 promotes osteogenic differentiation of hBMSCs and alleviates osteoporosis progression by targeting miRNA-760/ETS1 axis

Although long non-coding RNA LINC00963 has been reported to play a crucial regulatory role in osteoporosis (OP), its specific mechanism has not been well studied. Cell viability of human bone marrow mesenchymal stem cells (hBMSCs) transfected with short hairpin RNA targeting LINC00963 (sh-LINC00963) and negative control (sh-NC) was analysed by cell counting kit-8 (CCK-8) assay. Alkaline phosphatase (ALP) activity in hBMSCs transfected with sh-LINC00963 and sh-NC after induction by osteogenic medium (OM) on day 7 was detected. The protein expression levels of osteocalcin (OCN) and osteopontin (OPN) in hBMSCs transfected with sh-LINC00963 and sh-NC during OM induction on day 3 were detected by western blot. The relationship among LINC00963, miR-760, and E26 transformation specific-1 (ETS1) was determined by bioinformatics analysis, luciferase reporter assay, and RNA-binding protein immunoprecipitation (RIP) assay. A rat model with OP was established to confirm the role of LINC00963 in vivo. The expression level of LINC00963 was much lower in hBMSCs isolated from the discarded femoral head tissues of OP patients compared with that in health patients. Meanwhile, the expression level of LINC00963 was significantly increased and the expression level of miR-760 was decreased in hBMSCs during osteogenic induction. LINC00963 could bind to the 3'-untranslated region (3'-UTR) of miR-760 and negatively regulate the expression of miR-760, then promote the osteogenic differentiation in hBMSCs. ETS1 was identified as a target of miR-760. Moreover, overexpression of LINC00963 obviously reduced bone mineral density (BMD) of the left femur in OP rats and alleviated OP progression in vivo. Our results demonstrated that LINC00963 positively regulated the expression of ETS1 by directly targeting miR-760, and then promoted osteogenic differentiation of hBMSCs in vitro, and also attenuated OP progression in vivo, suggesting that LINC00963 might be a potential therapeutic target for OP.

Long non-coding RNA expression profiles in neutrophils revealed potential biomarker for prediction of renal involvement in SLE patients

OBJECTIVE

The long non-coding RNA plays an important role in inflammation and autoimmune diseases. The aim of this study is to screen and identify abnormally expressed lncRNAs in peripheral blood neutrophils of SLE patients as novel biomarkers and to explore the relationship between lncRNAs levels and clinical features, disease activity and organ damage.

METHODS

RNA-seq technology was used to screen differentially expressed lncRNAs in neutrophils from SLE patients and healthy donors. Based on the results of screening, candidate lncRNA levels in neutrophils of 88 SLE patients, 35 other connective disease controls, and 78 healthy controls were qualified by real-time quantitative polymerase chain reaction.

RESULTS

LncRNA expression profiling revealed 360 up-regulated lncRNAs and 224 down-regulated lncRNAs in neutrophils of SLE patients when compared with healthy controls. qPCR assay validated that the expression of Lnc-FOSB-1:1 was significantly decreased in neutrophils of SLE patients when compared with other CTD patients or healthy controls. It correlated negatively with SLE Disease Activity Index 2000 (SLEDAI-2K) score (r = -0.541, P < 0.001) and IFN scores (r = -0.337, P = 0.001). More importantly, decreased Lnc-FOSB-1:1 expression was associated with lupus nephritis. Lower baseline Lnc-FOSB-1:1 level was associated with higher risk of future renal involvement (within an average of 2.6 years) in patients without renal disease at baseline (P = 0.019).

CONCLUSION

LncRNA expression profile in neutrophils of SLE patients revealed differentially expressed lncRNAs. Validation study on Lnc-FOSB-1:1 suggest that it is a potential biomarker for prediction of near future renal involvement.

Regulation of Nrf2 signaling pathway in heart failure: Role of extracellular vesicles and non-coding RNAs

The balance between pro- and antioxidant molecules has been established as an important driving force in the pathogenesis of cardiovascular disease. Chronic heart failure is associated with oxidative stress in the myocardium and globally. Redox balance in the heart and brain is controlled, in part, by antioxidant proteins regulated by the transcription factor Nuclear factor erythroid 2-related factor 2 (Nrf2), which is reduced in the heart failure state. Nrf2 can, in turn, be regulated by a variety of mechanisms including circulating microRNAs (miRNAs) encapsulated in extracellular vesicles (EVs) derived from multiple cell types in the heart. Here, we review the role of the Nrf2 and antioxidant enzyme signaling pathway in mediating redox balance in the myocardium and the brain in the heart failure state. This review focuses on Nrf2 and antioxidant protein regulation in the heart and brain by miRNA-enriched EVs in the setting of heart failure. We discuss EV-mediated intra- and inter-organ communications especially, communication between the heart and brain via an EV pathway that mediates cardiac function and sympatho-excitation in heart failure. Importantly, we speculate how engineered EVs with specific miRNAs or antagomirs may be used in a therapeutic manner in heart failure.

The HIF-1α antisense long non-coding RNA drives a positive feedback loop of HIF-1α mediated transactivation and glycolysis

Hypoxia-inducible factor-1 (HIF-1) is a master driver of glucose metabolism in cancer cells. Here, we demonstrate that a HIF-1α anti-sense lncRNA, HIFAL, is essential for maintaining and enhancing HIF-1α-mediated transactivation and glycolysis. Mechanistically, HIFAL recruits prolyl hydroxylase 3 (PHD3) to pyruvate kinase 2 (PKM2) to induce its prolyl hydroxylation and introduces the PKM2/PHD3 complex into the nucleus via binding with heterogeneous nuclear ribonucleoprotein F (hnRNPF) to enhance HIF-1α transactivation. Reciprocally, HIF-1α induces HIFAL transcription, which forms a positive feed-forward loop to maintain the transactivation activity of HIF-1α. Clinically, high HIFAL expression is associated with aggressive breast cancer phenotype and poor patient outcome. Furthermore, HIFAL overexpression promotes tumor growth in vivo, while targeting both HIFAL and HIF-1α significantly reduces their effect on cancer growth. Overall, our results indicate a critical regulatory role of HIFAL in HIF-1α-driven transactivation and glycolysis, identifying HIFAL as a therapeutic target for cancer treatment.

Insights of rheumatoid arthritis biomarkers

Rheumatoid arthritis is a chronic, autoimmune connective tissue disease. In addition to joint involvement, extra-articular changes and organ complications also occur in the course of the disease. Untreated disease leads to disability and premature death. Therefore, it is important to recognise and begin treatment early. Based on the presence of rheumatoid factor and antibodies against citrullinated peptides, we can distinguish two forms of the disease: seropositive and seronegative. Research continues to elucidate the mechanisms of the onset of the disease, as well as to uncover factors that induce and influence the activity of the disease. The presence of markers that initially appear and affect the course of the disease can potentially aid in patient treatment. In this article, we have collected biomarkers of rheumatoid arthritis that are well understood as well as those that have been recently described.

Longitudinal assessment and stability of long non-coding RNA gene expression profiles measured in human peripheral whole blood collected into PAXgene blood RNA tubes

Objective

Long non-coding RNAs (lncRNAs) are emerging as novel biomarkers for a variety of chronic conditions including autoimmune disease. PAXgene Blood RNA tubes are routinely used in clinical research and molecular diagnostic development to capture RNA profiles in peripheral whole blood. While the stability of mRNA expression profiles captured using PAXgene tubes has been documented previously, no previous work has determined the stability of lncRNA expression profiles observed in PAXgene tubes stored at − 80 °C. Here we sought to determine the effects on lncRNA expression profiles following − 80 °C storage of total RNA templates, cDNA synthesized using fresh or frozen total RNA template, and the impact of freeze–thaw cycles on both total RNA and cDNA obtained from PAXgene tubes.

Results

We find that storage of whole blood in PAXgene tubes, total RNA and cDNA for up to 1 year at − 80 °C or up to ten total RNA or cDNA freeze–thaw cycles do not significantly alter lncRNA expression profiles compared to baseline. As monthly expression profiles were determined, some month to month lncRNA expression variability was observed. However, all monthly observations fell within the 95% confidence interval calculated at baseline.

Expression Profiling of Long Noncoding RNA and Messenger RNA in a Cecal Ligation and Puncture-Induced Colon Injury Mouse Model

Background

Emerging evidence reveals that long noncoding RNAs (lncRNAs) play important roles in the pathogenesis of sepsis. However, the detailed regulatory mechanisms of lncRNAs or whether certain lncRNA could serve as a biomarker in the septic colon remains unclear. The aim of this study was to investigate the profiles of lncRNAs and mRNAs in the septic colon through whole-transcriptome RNA sequencing and to reveal the associated regulatory mechanism.

Method and Result

We established a mouse model of sepsis by cecal ligation and puncture (CLP). Colon samples were collected upon CLP or sham surgery after 24 h. Whole-transcriptome RNA sequencing was performed to profile the relative expressions of lncRNAs and mRNAs. 808 lncRNAs and 1509 mRNAs were differentially found in the septic group compared with the sham group. Bioinformatics analysis including Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes pathway analysis (KEGG) was performed to predict the potential functions of these RNAs. GO analysis showed that the altered lncRNAs were enriched and involved in multiple immune responses, which may be a response to sepsis stress. KEGG analysis indicated that upregulated lncRNAs were significantly enriched in the p53 signaling pathway, NF-κB signaling pathway, and HIF-1 signaling pathway. Downregulated lncRNAs were mostly found to be involved in tight junction, leukocyte transendothelial migration, and HIF-1 signaling pathway.

Conclusion

Our results indicate that these altered lncRNAs and mRNAs may have crucial roles in the pathogenesis of sepsis. This study could contribute to extending the understanding of the function of lncRNAs in sepsis, which may help in searching for new diagnostic biomarkers and therapeutic targets to treat sepsis.

Increase in MEG3, MALAT1, NEAT1 significantly predicts the clinical parameters in patients with rheumatoid arthritis

Aim: This study investigated deregulation of lncRNAs MEG3, MALAT1, NEAT1 and their associations with clinical parameters in rheumatoid arthritis (RA). Materials & methods: LncRNAs MALAT1, MEG3, NEAT1 were quantified from peripheral blood mono-nuclear cells (PBMCs) and plasma of 82 RA patients with 15 matched controls and from knee fluid of 24 RA patients with ten osteoarthritis controls. Multivariate analyses were performed among lncRNAs and clinical parameters of RA. Results: MALAT1, MEG3, NEAT1 were increased in PBMCs, plasma, synovial fluid (p < 0.05) of RA patients. Significant correlations were observed for MEG3 with TJC (r = 0.29), NEAT1 with TJC (r = 0.49), swollen joint count (r = 0.20), DAS28-CRP (r = 0.29). Multivariate analysis revealed that 48.5% of TJC and 31.5% of swollen joint count could be predicted by lncRNAs. Conclusion: The findings suggested that the lncRNAs might be explored as probable markers in monitoring disease activity.

GAS5 protects against osteoporosis by targeting UPF1/SMAD7 axis in osteoblast differentiation

Osteoporosis is a common systemic skeletal disorder resulting in bone fragility and increased fracture risk. It is still necessary to explore its detailed mechanisms and identify novel targets for the treatment of osteoporosis. Previously, we found that a lncRNA named GAS5 in human could negatively regulate the lipoblast/adipocyte differentiation. However, it is still unclear whether GAS5 affects osteoblast differentiation and whether GAS5 is associated with osteoporosis. Our current research found that GAS5 was decreased in the bones and BMSCs, a major origin of osteoblast, of osteoporosis patients. Mechanistically, GAS5 promotes the osteoblast differentiation by interacting with UPF1 to degrade SMAD7 mRNA. Moreover, a decreased bone mass and impaired bone repair ability were observed in Gas5 heterozygous mice, manifesting in osteoporosis. The systemic supplement of Gas5-overexpressing adenoviruses significantly ameliorated bone loss in an osteoporosis mouse model. In conclusion, GAS5 promotes osteoblast differentiation by targeting the UPF1/SMAD7 axis and protects against osteoporosis.

LncRNA Neat1 positively regulates MAPK signaling and is involved in the pathogenesis of Sjögren's syndrome

OBJECTIVE

Primary Sjögren's syndrome (pSS) is a systemic autoimmune disease characterized by lymphocytic infiltration of the exocrine glands. Recent, studies have shown that the long noncoding RNA (lncRNA) NEAT1 plays a crucial role in regulating the immune response. However, studies on the lncRNA NEAT1 in pSS are limited. Exploring the role of the lncRNA NEAT1 in the pathogenesis of pSS was the purpose of this study.

METHODS

The expression of NEAT1 in peripheral blood mononuclear cells (PBMCs) of patients with pSS and healthy controls (HCs) was analyzed by real-time polymerase chain reaction (RT-PCR). Antisense oligonucleotides (ASOs) and siRNA or immune stimulation with PMA/ionomycin were used to perform loss-and-gain-of-function experiments. RT-PCR, enzyme-linked immunosorbent assay (ELISA), and Western blot were performed to detect the RNA and protein levels of specific genes induced by PMA/ionomycin stimulation. Microarray analysis was used to generate an overview of the genes that might be regulated by NEAT1.

RESULTS

Compared with that in HC patient cells, the expression of NEAT1 in pSS patients was mainly increased in peripheral T cells, including CD4⁺ and CD8⁺ T cells. Additionally, the expression of NEAT1 in CD4⁺ T cells of patients with pSS was positively correlated with the course of disease. NEAT1 expression in Jurkat cells was induced by PMA/ionomycin stimulation upon activation of the TCR-p38 pathway. Upregulation of NEAT1 expression also increased the expression of CXCL8 and TNF-α. Knocking down NEAT1 expression with an ASO suppressed the expression of CXCL8 and TNF-α in PMA/ionomycin-stimulated Jurkat cells. Then, we found that NEAT1 regulated the activation of MAPK pathway to regulate NEAT1-induced factors, selectively activating the expression of p-p38 and p-ERK1/2. Furthermore, we also detected the expression profile of Jurkat cells stimulated by PMA/ionomycin when NEAT1 was silenced or not, in order to produce an overview of NEAT1-regulated genes.

CONCLUSION

These results provide a new understanding of the mechanisms of pSS and reveal that NEAT1 is a positive regulator of pSS, which is of substantial significance to its pathogenesis. Thus, NEAT1 provides a potential therapeutic target for pSS.

Integrated Dissection of lncRNA-Perturbated Triplets Reveals Novel Prognostic Signatures Across Cancer Types

Long noncoding RNA (lncRNA)/microRNA(miRNA)/mRNA triplets contribute to cancer biology. However, identifying significative triplets remains a major challenge for cancer research. The dynamic changes among factors of the triplets have been less understood. Here, by integrating target information and expression datasets, we proposed a novel computational framework to identify the triplets termed as “lncRNA-perturbated triplets”. We applied the framework to five cancer datasets in The Cancer Genome Atlas (TCGA) project and identified 109 triplets. We showed that the paired miRNAs and mRNAs were widely perturbated by lncRNAs in different cancer types. LncRNA perturbators and lncRNA-perturbated mRNAs showed significantly higher evolutionary conservation than other lncRNAs and mRNAs. Importantly, the lncRNA-perturbated triplets exhibited high cancer specificity. The pan-cancer perturbator OIP5-AS1 had higher expression level than that of the cancer-specific perturbators. These lncRNA perturbators were significantly enriched in known cancer-related pathways. Furthermore, among the 25 lncRNA in the 109 triplets, lncRNA SNHG7 was identified as a stable potential biomarker in lung adenocarcinoma (LUAD) by combining the TCGA dataset and two independent GEO datasets. Results from cell transfection also indicated that overexpression of lncRNA SNHG7 and TUG1 enhanced the expression of the corresponding mRNA PNMA2 and CDC7 in LUAD. Our study provides a systematic dissection of lncRNA-perturbated triplets and facilitates our understanding of the molecular roles of lncRNAs in cancers.

Recent advances of long noncoding RNAs involved in the development of multiple sclerosis

Given the rapid increase of patients with autoimmune diseases and the lack of satisfactory therapies, the discovery of novel and effective therapeutic targets have been in an urgent demand. Recent studies have revealed that long noncoding RNAs (lncRNAs) play crucial roles in the development of multiple sclerosis (MS), which provides a new opportunity of uncovering novel mechanism associated with the progression of MS. This review highlights the dysregulation of lncRNAs in the development of MS in patients and animal models. Additionally, the potential clinical relevance of lncRNAs severed as therapeutic targets and diagnostic markers are discussed.

Analysis of long non-coding RNA expression profiles in high-glucose treated vascular endothelial cells

BACKGROUND

Diabetes mellitus is often associated with microvascular and macrovascular lesions, and hyperglycemia-induced vascular endothelial cell damage is a key factor.

METHODS

We investigated long non-coding RNAs (lncRNAs) and mRNAs that are affected by hyperglycemia-induced damage using human umbilical vein endothelial cells (HUVECs) as a model. HUVECs were cultured under high (25 mmol/L) or normal (5 mmol/L) glucose conditions for 6 d, and then lncRNAs and protein-coding transcripts were profiled by RNA-seq.

RESULT

Among 40,379 lncRNAs screened, 214 were upregulated (log2 [fold-change] > 1, FDR < 0.05) and 197 were downregulated (log2 [fold-change] < - 1, FDR < 0.05) in response to high-glucose. Furthermore, among 28,431 protein-coding genes screened, 778 were upregulated and 998 were downregulated. A total of 945 lncRNA/mRNA pairs were identified, including 126 differentially expressed lncRNAs predicted to target 201 mRNAs, among which 26 were cis-regulatory interactions. The corresponding lncRNA-mRNA network was composed of 354 lncRNA nodes, 1167 mRNA nodes and 9735 edges. Dozens of lncRNAs with high degree may play important roles in high-glucose-induced HUVEC damage, including ENST00000600527, NONHSAT037576.2, NONHSAT135706.2, ENST00000602127, NONHSAT200243.1, NONHSAT217282.1, NONHSAT176260.1, NONHSAT199075.1, NONHSAT067063.2, NONHSAT058417.2.

CONCLUSION

These observations may provide novel insights into the regulatory molecules and pathways of hyperglycemia-related endothelial dysfunction in diabetes-associated vascular disease.

TCONS_00483150 as a novel diagnostic biomarker of systemic lupus erythematosus

Aim: We aimed to identify differentially expressed Long noncoding RNAs (lncRNAs) and explore their functional roles in systemic lupus erythematosus (SLE). Materials & methods: We identified dysregulated lncRNAs and investigated their prognostic values and potential functions using MiRTarget2, catRAPID omics and Bedtools/blast/Pearson analyses. Results: Among the 143 differentially expressed lncRNAs, TCONS_00483150 could be used to distinguish patients with SLE from healthy controls and those with rheumatoid arthritis and patients with active/stable SLE from healthy controls. TCONS_00483150 was significantly correlated with anti-Rib-P antibody positivity and low C3 levels; TCONS_00483150 dysregulation might contribute to the metabolism of RNA and proteins in SLE patients. Conclusion: Overall, our findings offer a transcriptome-wide overview of aberrantly expressed lncRNAs in patients with SLE and highlight TCONS_00483150 as a potential novel diagnostic biomarker.

Gm15575 functions as a ceRNA to up-regulate CCL7 expression through sponging miR-686 in Th17 cells

Compelling evidence has demonstrated that Th17 cells play an essential role in the pathogenesis of multiple sclerosis (MS). Long noncoding RNAs (lncRNAs) have been confirmed as vital regulators of immune cell differentiation and other functions. However, whether and how lncRNAs influence Th17 cell differentiation and functional behaviors remain largely unclear. Here, we identified that a lncRNA, namely Gm15575, is specifically enriched in Th17 cells and spleen tissues of EAE mice. Functionally, knockdown of Gm15575 in Th17 cells suppressed the secretion of IL17A. Mechanistically, Gm15575 served as a competing endogenous RNA (ceRNA) to block the function of miR-686, positively regulating the expression of CCL7, a pro-inflammatory chemokine with high expression in Th17 cells, and Th17 differentiation. Taken together, our study revealed that Gm15575-miR-686 axis promoted the progression of EAE by regulating Th17 differentiation and expression of CCL7 which elucidated the pathogenesis of autoimmune diseases at genetic level. Gm15575 can be involved in the course of Th17-related autoimmune diseases.

Identification of novel genes associated with dysregulation of B cells in patients with primary Sjögren's syndrome

Background

The aim of this study was to identify the molecular mechanism of dysregulation of B cell subpopulations of primary Sjögren’s syndrome (pSS) at the transcriptome level.

Methods

We enrolled patients with pSS (n = 6) and healthy controls (HCs) (n = 6) in the discovery cohort using microarray and pSS (n = 14) and HCs (n = 12) in the validation cohort using quantitative PCR (qPCR). Peripheral B cells acquired from these subjects were separated by cell sorting into four subsets: CD38⁻IgD⁺ (Bm1), CD38⁺IgD⁺ (naive B cells), CD38^highIgD⁺ (pre-germinal centre B cells) and CD38^±IgD⁻ (memory B cells). We performed differentially expressed gene (DEG) analysis and weighted gene co-expression network analysis (WGCNA).

Results

Expression of the long non-coding RNA LINC00487 was significantly upregulated in all B cell subsets, as was that of HLA and interferon (IFN) signature genes. Moreover, the normalized intensity value of LINC00487 significantly correlated with the disease activity score of all pSS B cell subsets. Studies of human B cell lines revealed that the expression of LINC00487 was strongly induced by IFNα. WGCNA revealed six gene clusters associated with the B cell subpopulation of pSS. Further, SOX4 was identified as an inter-module hub gene.

Conclusion

Our transcriptome analysis revealed key genes involved in the dysregulation of B cell subpopulations associated with pSS.

Trial registration

Not required.

Long noncoding RNA PAHAL modulates locust behavioural plasticity through the feedback regulation of dopamine biosynthesis

Some long noncoding RNAs (lncRNAs) are specifically expressed in brain cells, implying their neural and behavioural functions. However, how lncRNAs contribute to neural regulatory networks governing the precise behaviour of animals is less explored. Here, we report the regulatory mechanism of the nuclear-enriched lncRNA PAHAL for dopamine biosynthesis and behavioural adjustment in migratory locusts (Locusta migratoria), a species with extreme behavioral plasticity. PAHAL is transcribed from the sense (coding) strand of the gene encoding phenylalanine hydroxylase (PAH), which is responsible for the synthesis of dopamine from phenylalanine. PAHAL positively regulates PAH expression resulting in dopamine production in the brain. In addition, PAHAL modulates locust behavioral aggregation in a population density-dependent manner. Mechanistically, PAHAL mediates PAH transcriptional activation by recruiting serine/arginine-rich splicing factor 2 (SRSF2), a transcription/splicing factor, to the PAH proximal promoter. The co-activation effect of PAHAL requires the interaction of the PAHAL/SRSF2 complex with the promoter-associated nascent RNA of PAH. Thus, the data support a model of feedback modulation of animal behavioural plasticity by an lncRNA. In this model, the lncRNA mediates neurotransmitter metabolism through orchestrating a local transcriptional loop.

The neurotransmitter dopamine is crucial for the neuronal and behavioral response in animals. Phenylalanine hydroxylase (PAH) is involved in dopamine biosynthesis and behavioral regulation in the migratory locust. However, the molecular mechanism for the fine tuning of PAH expression in behavioral response remains ambiguous. Here we discovered a nuclear-enriched lncRNA PAHAL that is transcribed from the coding strand of the PAH gene in the locust (i.e., sense lncRNA). PAHAL positively regulated PAH expression and dopamine production in the brain. In addition, PAHAL modulated behavioral aggregation of the locust. Mechanistically, PAHAL mediated the transcriptional activation of PAH by recruiting SRSF2, a transcription/splicing factor, to the promoter-associated nascent RNA of PAH. These data support a model of feedback modulation of dopamine biosynthesis and behavioral plasticity via a sense lncRNA in the catecholamine metabolic pathway.

Pathogenic Roles of Autoantibodies and Aberrant Epigenetic Regulation of Immune and Connective Tissue Cells in the Tissue Fibrosis of Patients with Systemic Sclerosis

Systemic sclerosis (SSc) is a multi-system autoimmune disease with tissue fibrosis prominent in the skin and lung. In this review, we briefly describe the autoimmune features (mainly autoantibody production and cytokine profiles) and the potential pathogenic contributors including genetic/epigenetic predisposition, and environmental factors. We look in detail at the cellular and molecular bases underlying tissue-fibrosis which include trans-differentiation of fibroblasts (FBs) to myofibroblasts (MFBs). We also state comprehensively the pro-inflammatory and pro-fibrotic cytokines relevant to MFB trans-differentiation, vasculopathy-associated autoantibodies, and fibrosis-regulating microRNAs in SSc. It is conceivable that tissue fibrosis is mainly mediated by an excessive production of TGF-β, the master regulator, from the skewed Th2 cells, macrophages, fibroblasts, myofibroblasts, and keratinocytes. After binding with TGF-β receptors on MFB, the downstream Wnt/β-catenin triggers canonical Smad 2/3 and non-canonical Smad 4 signaling pathways to transcribe collagen genes. Subsequently, excessive collagen fiber synthesis and accumulation as well as tissue fibrosis ensue. In the later part of this review, we discuss limited data relevant to the role of long non-coding RNAs (lncRNAs) in tissue-fibrosis in SSc. It is expected that these lncRNAs may become the useful biomarkers and therapeutic targets for SSc in the future. The prospective investigations in the development of novel epigenetic modifiers are also suggested.

Comprehensive expression profile of long non-coding RNAs in Peripheral blood mononuclear cells from patients with neuropsychiatric systemic lupus erythematosus

Background

Long noncoding RNAs (lncRNAs) are emerging as critical regulators of gene expression in the immune system, but their impact on neuropsychiatric systemic lupus erythematosus (NPSLE) remains unknown.

Methods

RNA sequencing analysis was used to screen the comprehensive expression profile of lncRNAs and messenger RNAs (mRNAs) in peripheral blood mononuclear cells (PBMCs) from NPSLE patients, active SLE patients who had never experienced neuropsychiatric manifestations (Non-NPSLE) and healthy controls. Differentially expressed (DE) lncRNA levels were validated by qRT-PCR in 26 NPSLE patients, 31 Non-NPSLE patients and 30 healthy controls. Further, correlations of DE lncRNAs with clinical manifestations of NPSLE patients were analyzed. Finally, a bioinformatic analysis was performed to investigate the potential functions of DE genes.

Results

Four hundred and fifty-one lncRNAs and 272 mRNAs were DE between the NPSLE patients and Non-NPSLE patients, among which, significantly upregulated expression levels of NONHSAT208182.1, NONHSAT182114.1, NONHSAT106801.2, NONHSAT039491.2, ENST00000356215, NONHSAT087499.2 and NONHSAT207026.1 while downregulated expression levels of NONHSAT001281.2 and NONHSAT024353.2 were further validated in PBMCs from NPSLE patients by qRT-PCR. Bioinformatic analysis suggested several gene ontology (GO) terms and signal pathways may play important roles in NPSLE development. Co-expression networks analysis indicated that 170 lncRNAs and 46 mRNAs were included in the co-expression network. The expression level of NONHSAT039491.2 was associated with the activity of SLE and the presence of anti-dsDNA, anti-RNP antibody, dizziness and headache. NONHSAT087499.2 level correlated with anti-RNA antibody, ENST00000356215 level correlated with olfactory threshold and oral ulcer. NONHSAT208182.1 level correlated with the presence of fever, unstable walking and urinary red blood cells. NONHSAT106801.2 correlated with frequency of B cells and the presence of fever. NONHSAT024353.2 level was associated with serum IgG levels and the presence of anti-SSA and disorder of consciousness.

Conclusions

Our data provided comprehensive evidence regarding the differential expression of lncRNAs in PBMCs from NPSLE patients, indicating that these DE lncRNAs may play roles in NPSLE development. Our finding shed light on the understanding of the molecular mechanisms of lncRNAs in the pathogenesis of NPSLE.

Long noncoding RNA LINC00963 promotes breast cancer progression by functioning as a molecular sponge for microRNA-625 and thereby upregulating HMGA1

Extensive research has shown that LINC00963 is aberrantly expressed in human cancers, and that dysregulation of LINC00963 is implicated in the initiation and progression of human cancers. The expression and functions of LINC00963 in breast cancer are still unclear. Our aims were to measure the expression of LINC00963 in breast cancer, determine its effects on malignant behaviors of tumor cells, and uncover the molecular events underlying the actions of LINC00963 in breast cancer. Herein, LINC00963 was found to be overexpressed in breast cancer samples, and its overexpression was correlated with lymph node metastasis, TNM stage and differentiation grade. Patients with breast cancer harboring higher LINC00963 expression showed shorter overall survival than did the patients with lower LINC00963 expression. Functional experiments revealed that depletion of LINC00963 inhibited breast cancer cell proliferation, migration, and invasion and facilitated apoptosis in vitro and impaired tumor growth in vivo. Mechanism investigation revealed that LINC00963 can interact with microRNA-625 (miR-625). LINC00963 worked as a competitive endogenous RNA for miR-625 to weaken the suppressive effect of miR-625 on high mobility group AT-hook 1 (HMGA1) in breast cancer cells. Furthermore, miR-625 inhibition and HMGA1 restoration both abrogated the effects of LINC00963 silencing on breast cancer cells. Our findings indicate that the LINC00963-miR-625-HMGA1 pathway plays an important role in the malignancy of breast cancer in vitro and in vivo. Hence, targeting this pathway may be a novel strategy against breast cancer.

LncRNA PICSAR promotes cell proliferation, migration and invasion of fibroblast-like synoviocytes by sponging miRNA-4701-5p in rheumatoid arthritis

Background

Long non-coding RNAs (lncRNAs) have drawn increasing attention because they play a pivotal role in various types of autoimmune diseases, including rheumatoid arthritis (RA). Fibroblast-like synoviocytes (FLSs), a prominent component of hyperplastic synovial pannus tissue, are the primary effector cells in RA synovial hyperplasia and invasion which can lead to joint destruction. In this study, we investigated whether lncRNAs could act as competing endogenous RNAs to regulate the pathological behaviors of RA-FLSs.

Methods

LncRNA microarray was conducted to establish lncRNA expression profiles in FLSs isolated from RA patients and healthy controls (HCs). Differentially expressed lncRNAs were verified by quantitative real-time PCR (qRT-PCR) on RA-FLSs and synovial fluid. The functional role of lncRNA PICSAR downregulation was evaluated in RA-FLSs. We conducted molecular biological analysis to predict miRNAs which have a potential binding site for PICSAR and further refined the results by qRT-PCR. Luciferase reporter assay was adopted to validate the interaction of lncRNA PICSAR and miR-4701-5p. Western Blot and qPCR were used to identify the target gene and protein. The functional role of miR-4701-5p upregulation was examined in RA-FLSs.

Findings

We identified a long intergenic non-protein-coding RNA162 (LINC00162), also known as lncRNA PICSAR (p38 inhibited cutaneous squamous cell carcinoma associated lincRNA), has significantly higher expression in RA-FLSs and RA synovial fluid. The cell proliferation, migration, invasion and proinflammatory cytokines production of RA-FLSs showed significant alterations after the lncRNA PICSAR suppression. Mechanistically, lncRNA PICSAR functioned through sponging miR-4701-5p in RA-FLSs.

Interpretation

Our results reveal PICSAR may exert an essential role in promoting synovial invasion and joint destruction by sponging miR-4701-5p in RA and that lncRNA PICSAR may act as a biomarker of RA.

lncRNAs: function and mechanism in cartilage development, degeneration, and regeneration

With the increasing incidence of cartilage-related diseases such as osteoarthritis (OA) and intervertebral disc degeneration (IDD), heavier financial and social burdens need to be faced. Unfortunately, there is no satisfactory clinical method to target the pathophysiology of cartilage-related diseases. Many gene expressions, signaling pathways, and biomechanical dysregulations were involved in cartilage development, degeneration, and regeneration. However, the underlying mechanism was not clearly understood. Recently, lots of long non-coding RNAs (lncRNAs) were identified in the biological processes, including cartilage development, degeneration, and regeneration. It is clear that lncRNAs were important in regulating gene expression and maintaining chondrocyte phenotypes and homeostasis. In this review, we summarize the recent researches studying lncRNAs’ expression and function in cartilage development, degeneration, and regeneration and illustrate the potential mechanism of how they act in the pathologic process. With continued efforts, regulating lncRNA expression in the cartilage regeneration may be a promising biological treatment approach.

LncRNA PVT1 links Myc to glycolytic metabolism upon CD4+ T cell activation and Sjögren's syndrome-like autoimmune response

The hyperproliferation and hyperactivation of CD4⁺ T cells in salivary gland tissue is a hallmark of Sjögren's syndrome (SS). However, the role of long noncoding RNAs (lncRNAs) in the pathological process of SS and CD4⁺ T cell activation has not been fully elucidated. Here, we reported that lncRNA PVT1 was involved in the glycolytic metabolism reprogramming and proliferation upon CD4⁺ T cell activation. Expression of PVT1 was positively related with CD4⁺ T cell activation both in SS patients and Ex vivo antigen simulation. Depletion of PVT1 decreased the proliferation of murine CD4⁺ T cells and Jurkat T cells upon activation. We also showed that expression of the transcription factor Myc is regulated by PVT1 under antigen simulation. Depletion of PVT1 significantly decreased the expression of glycolytic genes, as well as several pivotal glycolytic proteins that were directly transcribed by Myc. Measurement of glucose content and lactate secretion indicated a defected lactate secretion and glucose uptake in PVT1-depleted T cells. Additionally, the real-time extracellular acidification rate (ECAR) and oxygen consumption rate (OCR) measurement also affirmed that PVT1 maintains glycolytic levels, glycolytic capacity under stress and ECAR/OCR ratios during T cell activation. Polarizing assays indicate that PVT1 depletion defected the function of Th1 effector cells as well as down-regulated Myc expression and glycolytic levels. Furthermore, we observed increased glycolytic levels in CD4⁺ T cells from SS-like NOD/Ltj mice. Treatment with 2-deoxy-d-glucose (2-DG), an inhibitor of glycolysis, significantly decreased the extent of lymphocyte infiltration and CD4⁺ T cell numbers and attenuated the defect of salivary flow in the lesioned submandibular glands of NOD/Ltj mice. Thus, our study demonstrated that lncRNA PVT1, which was upregulated in the CD4⁺T cells of SS patients, could maintain the expression of Myc, thus controlling the proliferation and effector functions of CD4⁺ T cells through regulating the reprogramming of glycolysis. Inhibition of glycolysis could attenuate the proliferation of CD4⁺ T cells and the SS-like autoimmune response. Our study provides a novel mechanistic function of lncRNA PVT1 in the pathogenesis of SS.

Long non-coding RNAs in cutaneous biology and proliferative skin diseases: Advances and perspectives

Advances in transcriptome sequencing have revealed that the genome fraction largely encodes for thousands of non‐coding RNAs. Long non‐coding RNAs (lncRNAs), which are a class of non–protein‐coding RNAs longer than approximately 200 nucleotides in length, are emerging as key epigenetic regulators of gene expression recently. Intensive studies have characterized their crucial roles in cutaneous biology and diseases. In this review, we address the promotive or suppressive effects of lncRNAs on cutaneous physiological processes. Then, we focus on the pathogenic role of dysfunctional lncRNAs in a variety of proliferative skin diseases. These evidences suggest that lncRNAs have indispensable roles in the processes of skin biology. Additionally, lncRNAs might be promising biomarkers and therapeutic targets for cutaneous disorders.

Long non-coding RNA-HOTAIR promotes the progression of sepsis by acting as a sponge of miR-211 to induce IL-6R expression

Sepsis remains the primary cause of death in intensive care units and multiple long non-coding RNAs (lncRNAs) have been demonstrated to be dysregulated in samples of patients with sepsis. However, whether lncRNA-HOTAIR is involved in the etiology of sepsis remains unclear. The aim of the present study was to investigate the role of HOTAIR in sepsis and to reveal the associated mechanisms. A bioinformatics analysis and dual-luciferase reporter assay was performed to evaluate the interaction between HOTAIR and miR-211, as well as miR-211 and IL-6R. An animal model of sepsis was established in mice via cecal ligation and puncture. Interferon (IFN)-γ, interleukin (IL)-6, IL-17, tumor necrosis factor (TNF)-α, IL-1β, IL-6 receptor (R), microRNA (miR)-211 and HOTAIR expression was measured using reverse transcription-quantitative PCR. Cellular proliferation and apoptosis of monocytes were assessed using cell counting kit-8 assay and flow cytometry, respectively. miR-211 was revealed to be targeted by HOTAIR and IL-6R. The expression of IFN-γ, IL-6, IL-17, TNF-α, IL-1β, IL-6R and HOTAIR was significantly upregulated in the septic mice, whereas miR-211 expression was downregulated. The overexpression of hox transcript antisense RNA (HOTAIR) and knockdown of miR-211 were associated with an increased expression of IFN-γ, IL-6, IL-17, TNF-α, IL-1β and IL-6R in monocytes, while the overexpression of miR-211 exhibited the opposite effect. HOTAIR overexpression and miR-211 knockdown significantly inhibited cellular proliferation and promoted monocyte apoptosis, whereas the overexpression of miR-211 exhibited the opposite effects in monocytes. Therefore, HOTAIR may promote the progression of sepsis by indirectly regulating the expression of IL-6R via miR-211.

lncRNA TUG1 modulates proliferation, apoptosis, invasion, and angiogenesis via targeting miR-29b in trophoblast cells

BACKGROUND

Pre-eclampsia (PE) is regarded as the leading cause of maternal and neonatal morbidity and mortality. Nevertheless, the potential mechanism for the regulation of trophoblast behaviors and the pathogenesis of PE remain largely elusive. Recently, accumulating evidence emphasized that aberrant expression of long non-coding RNAs (lncRNAs) functions as imperative regulators in human diseases, including PE. Thus, identifying PE-related specific lncRNAs to uncover the underlying molecular mechanism is of much significance. However, the functional roles and underlying mechanisms of lncRNAs in PE progression remain unclear.

METHOD

Placenta tissues obtained from patients with PE and healthy pregnant women were performed to measure TUG1 expression by qRT-PCR analysis. Transient transfections were conducted to alter TUG1 expression. Cell Counting Kit-8 (CCK-8) and flow cytometry assays were carried out to assess cell proliferation and apoptosis, respectively. Transwell and tube formation assays were performed to measure the capacity of cell invasion and angiogenesis. Moreover, the luciferase reporter assay was subjected to verify the binding relationship between TUG1 and miR-29b. Western blot analysis was performed to detect the expression of key proteins in the PI3K/AKT and ERK pathway.

RESULTS

Here, we identified a lncRNA, TUG1, which was notably decreased in placental samples of PE patients. Functional experiments of loss- or gain-of-function assays also verified that ectopic expression of TUG1 promoted cell proliferation, invasion, and angiogenesis, but negatively regulated cell apoptosis, whereas TUG1 inhibition presented the opposite effects. Furthermore, mechanistic researches revealed that TUG1 could act as a molecular sponge for miR-29b, thus regulating MCL1, VEGFA, and MMP2 to modulate PE development.

CONCLUSIONS

Taken together, our findings demonstrated that TUG1 exerts as a critical role in PE progression, which might furnish a novel therapeutic marker for PE treatment.

Long noncoding RNA nuclear enriched abundant transcript 1 promotes the proliferation and migration of Schwann cells by regulating the miR-34a/Satb1 axis

The proliferation and migration of Schwann cells contribute to axonal outgrowth and functional recovery after peripheral nerve injury. Studies have found that long noncoding RNAs (lncRNAs) were abnormally expressed after peripheral nerve injury and they played vital roles in peripheral nerve regeneration. LncRNA nuclear enriched abundant transcript 1 (NEAT1) was increased in the cerebral cortex surrounding the injury site of mice after traumatic brain injury, and it promoted the functional recovery in mice. However, its role and mechanism in peripheral nerve injury remain unknown. The expression of NEAT1, miR-34a, and Special AT-rich sequence-binding protein-1 (Satb1) was detected in the sciatic nerve of mice after sciatic nerve crush at 0, 1, 4 and 7 days. The effects of NEAT1 on the proliferation and migration of Schwann cells were detected by 5-Ethynyl-20-deoxyuridine (Edu) and transwell by gain- and loss-of-functions. The mechanism was focused on the miR-34a/Satb1 pathway. In addition, the effect of NEAT1 in Schwann cells on axon outgrowth of dorsal root ganglion neurons was further investigated. We found that the NEAT1 and Satb1 expression was increased, whereas miR-34a was reduced, in injured sciatic nerve at different time points. Overexpression of NEAT1 promoted, whereas knockdown of NEAT1 suppressed the proliferation and migration of Schwann cells. NEAT1 functioned as a competing endogenous RNA to regulate the Satb1 expression via sponging miR-34a. NEAT1 enhanced the axon outgrowth of dorsal root ganglion neurons via regulating the miR-34a and Satb1 expression. In conclusion, NEAT1 promotes the proliferation and migration of Schwann cell via miR-34a/Satb1, which may provide a new approach to peripheral nerve regeneration.

The expression of GAS5, THRIL, and RMRP lncRNAs is increased in T cells of patients with rheumatoid arthritis

OBJECTIVE

Long non-coding RNAs (lncRNAs) comprise a large and diverse group of non-coding RNAs (ncRNAs) with important regulatory roles in various biological processes, including the immune system regulation. Rheumatoid arthritis (RA) as an autoimmune disease initiates inflammation in the synovial joints. T cells infiltrating into the synovial membrane have an important role in the pathogenesis of RA. The aim of the current investigation was to analyze the expression of four lncRNAs in the T cells from RA patients and healthy controls.

METHODS

In the current study, we investigated the expression of GAS5, RMRP, IFNϒ-AS1, and THRIL lncRNAs in circulating T cells from 20 patients with RA and 18 healthy matched controls by quantitative real-time PCR. T cell isolation was accomplished using the MAC method. We also analyzed the correlation between lncRNA expression and clinical parameters. Also, the mRNA expression levels of IL-17 and TNF-α and the association between lncRNAs and these cytokines were examined.

RESULTS

The results indicate that T cells of RA patients display increased levels of GAS5 (3.31-fold, p = 0.007), RMRP (2.43-fold, p = 0.02), and THRIL (2.14-fold, p = 0.03) lncRNAs compared with those of controls. Furthermore, a positive correlation was found between RMRP expression and disease duration in RA. Receiver operating characteristic (ROC) curve of GAS5, RMRP, and THRIL has a discriminative value in comparing RA patients and controls.

CONCLUSION

The results suggest lncRNAs may be involved in T cell dysfunction in RA. Further studies are required to see whether these lncRNAs have an effect on dysregulation of immune responses in RA disease. Key Points • 70% of non-coding sequences in the human genome are transcribed to RNA. • A growing body of evidence shows the importance of lncRNAs in innate and adaptive immune cell differentiation and functions. • Important recent works suggest a key role of immune cell lncRNAs in autoimmune processes and diseases including RA.

Circular RNAs in hypertension: challenges and clinical promise

Hypertension (HT), or high blood pressure (BP), is a chronic disease that is common among populations worldwide. The occurrence of HT is one of the leading causes of cardiovascular morbidity and mortality in adults. Although multiple studies have stressed the multifactorial and multigenic nature of HT, uncertainties about its etiology persist, and current diagnostic biomarkers can explain only a small part of the phenotypic variance of BP. Hence, the search for novel biomarkers that enable early disease prevention and guided therapy is warranted. Regulatory circRNAs have emerged as the newest player in HT-related gene networks and hold promise for improving the accuracy of diagnosis. These RNAs are genome products that are formed through back-splicing of specific regions of pre-mRNAs. Evidence suggests that these RNA species are involved in various metabolic diseases. Recent studies have revealed that aberrant expression of circRNAs is relevant to the occurrence and development of HT. Accordingly, circRNAs are proposed as a new generation of predictive biomarkers and potential therapeutic targets for different forms of HT, including pulmonary hypertension and preeclampsia. This paper presents an overview of the findings from current research focusing on the emerging role of circRNAs in the pathogenesis of hypertension. Furthermore, some of the challenges encountered by circRNA studies are highlighted, and perspectives are provided on the future of research in this area.

Long noncoding RNA LINC00673-v4 promotes aggressiveness of lung adenocarcinoma via activating WNT/β-catenin signaling

This study uncovers a long noncoding RNA (lncRNA)-mediated mechanism underlying lung adenocarcinoma (LAD) metastasis. We here report that lncRNA LINC00673-v4 expression is up-regulated in LAD and is associated with disease progression. At the molecular level, LINC00673-v4 acts as a scaffold molecule that promotes the interaction between DDX3 and CK1ε and thus the phosphorylation of dishevelled, which subsequently activates WNT/β-catenin signaling and consequently causes aggressiveness of LAD. Treatment with antisense oligonucleotides against LINC00673-v4 strongly suppresses LAD metastasis in vivo.

It is well recognized that metastasis can occur early in the course of lung adenocarcinoma (LAD) development, and yet the molecular mechanisms driving this capability of rapid metastasis remain incompletely understood. Here we reported that a long noncoding RNA, LINC00673, was up-regulated in LAD cells. Of note, we first found that LINC00673-v4 was the most abundant transcript of LINC00673 in LAD cells and its expression was associated with adverse clinical outcome of LAD. In vitro and in vivo experiments demonstrated that LINC00673-v4 enhanced invasiveness, migration, and metastasis of LAD cells. Mechanistically, LINC00673-v4 augmented the interaction between DDX3 and CK1ε and thus the phosphorylation of dishevelled, which subsequently activated WNT/β-catenin signaling and consequently caused aggressiveness of LAD. Antagonizing LINC00673-v4 suppressed LAD metastasis in vivo. Together, our data suggest that LINC00673-v4 is a driver molecule for metastasis via constitutively activating WNT/β-catenin signaling in LAD and may represent a potential therapeutic target against the metastasis of LAD.

The role of the protein-RNA recognition code in neurodegeneration

MicroRNAs are small endogenous RNAs that pair and bind to sites on mRNAs to direct post-transcriptional repression. However, there is a possibility that microRNAs directly influence protein structure and activity, and this influence can be termed post-translational riboregulation. This conceptual review explores the literature on neurodegenerative disorders. Research on the association between neurodegeneration and RNA-repeat toxicity provides data that support a protein-RNA recognition code. For example, this code explains why hnRNP H and SFPQ proteins, which are involved in amyotrophic lateral sclerosis, are sequestered by the (GGGGCC)n repeat sequence. Similarly, it explains why MNBL proteins and (CTG)n repeats in RNA, which are involved in myotonic dystrophy, are sequestered into RNA foci. Using this code, proteins involved in diseases can be identified. A simple protein BLAST search of the human genome for amino acid repeats that correspond to the nucleotide repeats reveals new proteins among already known proteins that are involved in diseases. For example, the (CAG)n repeat sequence, when transcribed into possible peptide sequences, leads to the identification of PTCD3, Rem2, MESP2, SYPL2, WDR33, COL23A1, and others. After confirming this approach on RNA repeats, in the next step, the code was used in the opposite manner. Proteins that are involved in diseases were compared with microRNAs involved in those diseases. For example, a reasonable correspondence of microRNA 9 and 107 with amyloid-β-peptide (Aβ42) was identified. In the last step, a miRBase search for micro-nucleotides, obtained by transcription of a prion amino acid sequence, revealed new microRNAs and microRNAs that have previously been identified as involved in prion diseases. This concept provides a useful key for designing RNA or peptide probes.