Potential role of circulating long noncoding RNA MALAT1 in predicting disease risk, severity, and patients' survival in sepsis

LncRNA-mRNA co-expression analysis reveals aquaporin-9-promoted neutrophil extracellular trap formation and inflammatory activation in sepsis

Sepsis is a life-threatening condition caused by an excessive inflammatory response to an infection. However, the precise regulatory mechanism of sepsis remains unclear. Using a strand-specific RNA-sequencing, we identified 115 hub differentially expressed long noncoding RNAs (lncRNAs) and 443 mRNAs in septic patients, primarily participated in crucial pathways including neutrophil extracellular trap (NET) formation and toll-like receptor signaling. Notably, NETs related gene aquaporin-9 (AQP9) and its associated lncRNAs exhibited significant upregulation in septic neutrophils. Functional experiments revealed AQP9 interacts with its lncRNAs to augment the formation of neutrophil NETs. In murine sepsis models, AQP9 inhibition with phloretin reduced proinflammatory cytokine production and lung damage. These findings provide crucial insights into the regulatory role of AQP9 in sepsis, unraveling its interaction with associated lncRNAs in transmitting downstream signals, holding promise in informing the development of novel therapeutic strategies aimed at ameliorating the debilitating effects of sepsis.

MALAT1 predicts the prognosis of severe community-acquired pneumonia in pediatric patients

BACKGROUND

To evaluate the role of metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in the prognosis of severe community-acquired pneumonia (CAP) in children.

METHODS

According to the median MALAT1 value of 3.2 at baseline, 93 pediatric patients with severe CAP were divided into low (n = 46, median MALAT1 level = 1.9) or high (n = 47, median MALAT1 level = 4.5) MALAT1 groups. Another 93 age-, gender-, and body mass index (BMI)-matched healthy individuals were included in the control group using the propensity-score matching (PSM) method. A multivariate Cox proportional hazards model was used to explore the association of MALAT1 level with the 28-day mortality after controlling for potential confounding factors.

RESULTS

The MALAT1 expressions were significantly higher in the patients with severe CAP compared with those in the healthy controls (3.2 vs. 0.9, P < 0.01). The receiver operating characteristic (ROC) analysis showed that the area under the curve (AUC) was 0.927 when the cut-off value of MALAT1 was 1.5. Moreover, the MALAT1 expressions were substantially lower in survivals than non-survivals (3.8 vs. 2.6, P < 0.01), and the multivariate Cox regression analysis indicated a positive association between MALAT1 levels and mortality risk (HR = 3.32; 95% CI: 1.05-10.47; P = 0.04).

CONCLUSION

MALAT1 might be a promising marker for predicting the prognosis of severe CAP in pediatric patients.

Roles of lncRNA-MALAT1 in the Progression and Prognosis of Gliomas

Long noncoding RNAs (lncRNAs) represent a large subgroup of RNA transcripts that lack the function of coding proteins and may be essential universal genes involved in carcinogenesis and metastasis. LncRNA metastasis-associated lung adenocarcinoma transcript 1 (lncRNAMALAT1) is overexpressed in various human tumors, including gliomas. However, the biological function and molecular mechanism of action of lncRNA-MALAT1 in gliomas have not yet been systematically elucidated. Accumulating evidence suggests that the abnormal expression of lncRNA-MALAT1 in gliomas is associated with various physical properties of the glioma, such as tumor growth, metastasis, apoptosis, drug resistance, and prognosis. Furthermore, lncRNAs, as tumor progression and prognostic markers in gliomas, may affect tumorigenesis, proliferation of glioma stem cells, and drug resistance. In this review, we summarize the knowledge on the biological functions and prognostic value of lncRNA-MALAT1 in gliomas. This mini-review aims to deepen the understanding of lncRNA-MALAT1 as a novel potential therapeutic target for the individualized precision treatment of gliomas.

RNF7 Induces Skeletal Muscle Cell Apoptosis and Arrests Cell Autophagy via Upregulation of THBS1 and Inactivation of the PI3K/Akt Signaling Pathway in a Rat Sepsis Model

Recently, long noncoding RNAs (lncRNAs) have been highlighted for extensive functionality in sepsis. In this study, we aimed to explore the role of RNF7 in the progression of sepsis. We initially established a rat model of sepsis through cecal ligation and puncture induction, whereupon RNF7 expression was determined by RT-qPCR. Following adenovirus infection, the role of RNF7 in muscle injury, skeletal muscle protein metabolism, oxidative stress, and inflammation in sepsis rats was analyzed. Then, downstream mechanisms of RNF7 were identified and validated. Further, lipopolysaccharide was applied to treat myoblast to further demonstrate the in vitro role of RNF7. Our results showed that RNF7 expression was upregulated during sepsis. Overexpression of RNF7 worsened the sepsis-induced skeletal muscle injury, induced skeletal muscle protein metabolism, oxidative stress, and inflammation in sepsis rats. Meanwhile, overexpression of RNF7 elevated thrombospondin-1 (THBS1) expression. Silencing of RNF7 inhibited THBS1 and activated the PI3K/Akt signaling pathway, arresting the release of inflammatory factors and oxidative stress levels in skeletal muscle cells. Altogether, RNF7 may promote skeletal muscle cell apoptosis while simultaneously inhibiting cell autophagy through the promotion of THBS1 and inactivation of the PI3K/Akt signaling pathway.

The ability of long non-coding RNA RP11-284N8.3 to predict the risk, the severity and 28-day mortality of adults with sepsis

In a prior study, we identified a novel sepsis specific long noncoding RNAs (lncRNA) RP11-284N8.3, which may primarily participate in T cell activation and immune response during sepsis. However, the clinical significance of lncRNA RP11-284N8.3 in sepsis remains entirely unknown. This single-center prospective cohort study enrolled 147 adults with sepsis and 74 healthy controls (HCs) with matched age and sex between January 2021 and November 2022 at our hospital. Blood samples and clinical data were collected from HCs at enrollment and from adults with sepsis within 24 hours after admission. lncRNA RP11-284N8.3 expression was detected by RT-qPCR. The relative expression of lncRNA RP11-284N8.3 was significantly decreased in adults with sepsis compared to HCs (P < .0001), in adults with septic shock compared to adults without shock (P = .0012), and in 28-day deaths compared to 28-day survivors (P = .0006). receiver operating characteristic curves of lncRNA RP11-284N8.3 in predicting sepsis severity and 28-day mortality showed an area under the curve of 0.6570 (95% confidence interval [CI]: 0.5701-0.7440) and an area under the curve of 0.6765 (95% CI: 0.5809-0.7721), respectively. Multivariate logistic regression analysis revealed that lncRNA RP11-284N8.3 was an independent risk factor for 28-day mortality in adults with sepsis (odds ratio: 0.1057, 95% CI: 0.0115-0.7746, P = .0328). Low expression of lncRNA RP11-284N8.3 is correlated with increased risk, severity and 28-day mortality in adults with sepsis, and it may function as a potential biomarker to facilitate the diagnosis and management of sepsis.

ATP2B1-AS1 exacerbates sepsis-induced cell apoptosis and inflammation by regulating miR-23a-3p/TLR4 axis

BACKGROUND

Sepsis is a life-threatening disease with dominant mortality. Its early diagnosis and treatment can improve prognosis and reduce mortality. Long noncoding RNAs (lncRNAs) ATPase plasma membrane Ca2+ transporting 1 antisense RNA 1 (ATP2B1-AS1) is dysregulated and is involved in the progression of various diseases. Nevertheless, the role of ATP2B1-AS1 in sepsis remains unclear.

METHODS

A human monocytic cell line, THP-1 cells, was stimulated to induce a model of sepsis in vitro. The levels of ATP2B1-AS1, miR-23a-3p, and TLR4 were assessed by real-time quantitative polymerase chain reaction. The role of ATP2B1-AS1 in cell apoptosis and inflammation was explored by flow cytometry, Western blot analysis and enzyme-linked immunosorbent serologic assay. The binding sites between ATP2B1-AS1 and miR-23a-3p, and between miR-23a-3p and TLR4 were predicted by BiBiServ and the Encyclopedia of RNA Interactomes (ENCORI) online sites, respectively, and confirmed by the luciferase assay.

RESULTS

The level of ATP2B1-AS1 was increased in lipopolysaccharide (LPS)-treated THP-1 cells. LPS increased apoptosis ratio, relative protein expressions of pro-apoptotic factors, and relative messenger RNA (mRNA) level and concentrations of pro-inflammatory cytokines, but decreased the relative expression of anti-apoptosis protein and relative mRNA level and concentrations of anti-inflammatory factor. All these alterations were reversed with transfection of shATP2B1-AS1 into THP-1 cells. Moreover, ATP2B1-AS1 directly bound miR-23a-3p and negatively modulated the level of miR-23a-3p. Meanwhile, TLR4 was directly targeted by miR-23a-3p, and negatively and positively modulated by miR-23a-3p and ATP2B1-AS1, respectively.

CONCLUSION

ATP2B1-AS1 aggravated apoptosis and inflammation by modulating miR-23a-3p/TLR4 axis in LPS-treated THP-1 cells.

Long non-coding RNA lnc-CHAF1B-3 promotes renal interstitial fibrosis by regulating EMT-related genes in renal proximal tubular cells

Renal interstitial fibrosis (RIF) is a common pathological manifestation of chronic kidney diseases. Epithelial-mesenchymal transition (EMT) of tubular epithelial cells is considered a major cause of RIF. Although long non-coding RNAs (lncRNAs) are reportedly involved in various pathophysiological processes, the roles and underlying molecular mechanisms of lncRNAs in the progression of RIF are poorly understood. In this study, we investigated the function of lncRNAs in RIF. Microarray assays showed that expression of the lncRNA lnc-CHAF1B-3 (also called claudin 14 antisense RNA 1) was significantly upregulated in human renal proximal tubular cells by both transforming growth factor-β1 (TGF-β1) and hypoxic stimulation, accompanied with increased expression of EMT-related genes. Knockdown of lnc-CHAF1B-3 significantly suppressed TGF-β1-induced upregulated expression of collagen type I alpha 1, cadherin-2, plasminogen activator inhibitor-1, snail family transcriptional repressor I (SNAI1) and SNAI2. Quantitative reverse transcriptase PCR analyses of paraffin-embedded kidney biopsy samples from IgA nephropathy patients revealed lnc-CHAF1B-3 expression was correlated positively with urinary protein levels and correlated negatively with estimated glomerular filtration rate. In situ hybridization demonstrated that lnc-CHAF1B-3 is expressed only in proximal tubules. These findings suggest lnc-CHAF1B-3 affects the progression of RIF by regulating EMT-related signaling. Thus, lnc-CHAF1B-3 is a potential target in the treatment of RIF.

LncRNA MALAT1 Targets miR-9-3p to Upregulate SAP97 in the Hippocampus of Mice with Vascular Dementia

Vascular dementia (VaD) is the second most common subtype of dementia, but the precise mechanism underlying VaD is not fully understood. Long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) can act as a key regulator in physiological and pathological processes, including neurological disorders, but whether it is correlated with VaD has not been elucidated. In this study, we established a mouse model of VaD by the transient bilateral common carotid artery occlusion surgery. As expected, the Morris water maze showed that VaD mice had significant deficits in spatial learning and memory. MALAT1 was elevated in the hippocampus of VaD mice. Additionally, we found that microRNA (miR)-9-3p was downregulated in the VaD hippocampus. By performing a dual-luciferase report assay, we verified the binding relationship between MALAT1 and miR-9-3p. Interestingly, synapse-associated protein-97 (SAP97), a well-known gene related to synaptic functions, was found upregulated in the hippocampus of VaD mice. In vitro experiments performed on hippocampal neurons demonstrated that miR-9-3p negatively regulated SAP97 expression. The downregulation of MALAT1 in hippocampal neurons increased miR-9-3p and reduced SAP97, whereas miR-9-3p inhibition rescued the MALAT1 downregulation-mediated SAP97 reduction. In conclusion, the present study reported the alterations in the expression levels of MALAT1, miR-9-3p, and SAP97 in the hippocampus of VaD mice, suggesting that MALAT1 targets miR-9-3p to upregulate SAP97 in the hippocampus of mice with VaD. This work will be helpful for understanding the molecular mechanisms of VaD.

Long Non-Coding RNAs ANRIL and HOTAIR Upregulation is Associated with Survival in Neonates with Sepsis in a Neonatal Intensive Care Unit

Background

Recently, long non-coding RNAs (lncRNAs) have emerged as potential molecular biomarkers for sepsis. We aimed to profile the expression signature of three inflammation-related lncRNAs, MALAT1, ANRIL, and HHOTAIR, in the plasma of neonates with sepsis and correlate these signatures with the phenotype.

Patients and Methods

This case–control study included 124 neonates with sepsis (88 survivors/36 non-survivors) admitted to the neonatal ICU and 17 healthy neonates. The relative expressions were quantified by real-time PCR and correlated to the clinic-laboratory data.

Results

The three circulating lncRNAs were upregulated in the cases; the median levels were MALAT1 (median = 1.71, IQR: −0.5 to 3.27), ANRIL (median = 1.09, IQR: 0.89 to 1.30), and HOTAIR (median = 1.83, IQR: 1.44 to 2.41). Co-expression analysis showed that the three studied lncRNAs were directly correlated (all p-values <0.001). Overall and stratification by sex analyses revealed significantly higher levels of the three lncRNAs in non-survivors compared to the survivor group (all p-values <0.001). Principal component analysis showed a clear demarcation between the two study cohorts in males and females. Cohorts with upregulated ANRIL (hazard ratio; HR = 4.21, 95% CI = 1.15–10.4, p=0.030) and HOTAIR (HR = 2.49, 95% CI = 1.02–6.05, p=0.044) were at a higher risk of mortality.

Conclusion

Circulatory MALAT1, ANRIL, and HOTAIR were upregulated in neonatal sepsis, and the latter two may have the potential as prognostic biomarkers for survival in neonatal sepsis.

Ablation of long noncoding RNA MALAT1 activates antioxidant pathway and alleviates sepsis in mice

The metastasis-associated lung adenocarcinoma transcript1 (MALAT1) is a long noncoding RNA (lncRNA) and is known for its role in cancer development and prognosis. In this study, we report that MALAT1 plays an important role in regulating acute inflammatory responses in sepsis. In patient samples, MALAT1 expression was positively correlated with severity of sepsis. In cultured macrophages, LPS treatment significantly induced MALAT1 expression, while genetic ablation of MALAT1 greatly reduced proinflammatory cytokine levels. Furthermore, MALAT1-ablated mice had significantly increased survival rates in cecal ligation and puncture (CLP)-induced sepsis and LPS-induced endotoxemia. One novel and salient feature of MALAT1-ablated mice is greatly reduced ROS level in macrophages and other cell types and increased glutathione/oxidized glutathione (GSH/GSSG) ratio in macrophages, suggesting an increased antioxidant capacity. We showed a mechanism for MALAT1 ablation leading to enhanced antioxidant capacity is through activation of methionine cycle by epitranscriptomical regulation of methionine adenosyltransferase 2A (MAT2A). MAT2A 3′UTR can be methylated by METTL16 which was known to directly bind to MALAT1. MALAT1 ablation was found to reduce methylation in MAT2A hairpin1 and increase MAT2A protein levels. Our results suggest a MALAT1-METTL16-MAT2A interactive axis which may be targeted for treatments of sepsis.

Non-Coding RNA Networks as Potential Novel Biomarker and Therapeutic Target for Sepsis and Sepsis-Related Multi-Organ Failure

According to “Sepsis-3” consensus, sepsis is a life-threatening clinical syndrome caused by a dysregulated inflammatory host response to infection. A rapid identification of sepsis is mandatory, as the extent of the organ damage triggered by both the pathogen itself and the host’s immune response could abruptly evolve to multiple organ failure and ultimately lead to the death of the patient. The most commonly used therapeutic strategy is to provide hemodynamic and global support to the patient and to rapidly initiate broad-spectrum empiric antibiotic therapy. To date, there is no gold standard diagnostic test that can ascertain the diagnosis of sepsis. Therefore, once sepsis is suspected, the presence of organ dysfunction can be assessed using the Sepsis-related Organ Failure Assessment (SOFA) score, although the diagnosis continues to depend primarily on clinical judgment. Clinicians can now rely on several serum biomarkers for the diagnosis of sepsis (e.g., procalcitonin), and promising new biomarkers have been evaluated, e.g., presepsin and adrenomedullin, although their clinical relevance in the hospital setting is still under discussion. Non-codingRNA, including long non-codingRNAs (lncRNAs), circularRNAs (circRNAs) and microRNAs (miRNAs), take part in a complex chain of events playing a pivotal role in several important regulatory processes in humans. In this narrative review we summarize and then analyze the function of circRNAs-miRNA-mRNA networks as putative novel biomarkers and therapeutic targets for sepsis, focusing only on data collected in clinical settings in humans.

MALAT1 regulates PCT expression in sepsis patients through the miR‐125b/STAT3 axis

Background

Procalcitonin (PCT) is an important marker in diagnosing sepsis. However, some other diseases can also cause an increase in PCT. PCT still has some limitations in the clinical application of diagnosing sepsis. Therefore, it is of great significance to clarify the regulatory mechanism of PCT expression in sepsis and provide new therapeutic targets for sepsis.

Methods

Blood samples from clinical patients were collected, and peripheral blood monocytes were isolated. Bioinformatics was performed to find the ceRNA regulatory network of STAT3/PCT. MALAT1 and miR‐125b were detected by qRT‐PCR. MALAT1 was located by fluorescence in situ hybridization (FISH) in U937 cells, and the regulatory relationship between MALAT1, miR‐125b, and STAT3 was verified by double luciferase activity report and RNA pull‐down assay. U937 cells were transfected with miR‐125b, and the effects of the MALAT1/miR‐125b/STAT3 pathway on gene and protein secretion levels of PCT were verified by qRT‐PCR, western blot, and ELISA.

Results

In the serum of sepsis patients and lipopolysaccharide(LPS)‐induced U937 cells, MALAT1, STAT3, and PCT gene expression levels were significantly increased, while miR‐125b expression level was decreased. FISH results showed that the MALAT1 transcript was mainly located in the nucleus. The double luciferase activity report and RNA pull‐down assay results suggested a targeted regulatory relationship between MALAT1, miR‐125b, and STAT3. LPS‐induced U937 cells transfection with MALAT1 siRNA decreased STAT3 protein expression and phosphorylation level and the expression of PCT. Co‐transfection with miR‐125b inhibitor effectively reversed this phenomenon.

Conclusions

MALAT1 could upregulate the expressions of STAT3 and PCT by targeted adsorption of miR‐125b.

Long non-coding RNA MALAT1 silencing elevates microRNA-26a-5p to ameliorate myocardial injury in sepsis by reducing regulator of calcineurin 2

OBJECTIVE

Sepsis is a leading cause of morbidity and mortality after surgery. We aimed to explore the role of long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) sponging microRNA-26a-5p in sepsis-induced myocardial injury by regulating regulator of calcineurin 2 (Rcan2).

METHODS

HL-1 cells were incubated with lipopolysaccharide (LPS) to induce in vitro cardiomyocyte injury models, which were then treated with silenced MALAT1 vector, miR-26a-5p mimic or Rcan2 overexpression vector. Next, inflammatory factor level and apoptosis of cells were determined. The in vivo mouse models were constructed by intraperitoneal injection of LPS. The modeled mice were injected with relative oligonucleotides and the pathology, apoptosis, and inflammation in mouse myocardial tissues were assessed. Expression of MALAT1, miR-26a-5p and Rcan2 in vivo and in vitro was evaluated.

RESULTS

MALAT1 and Rcan2 were upregulated while miR-26a-5p was downregulated in LPS-treated HL-1 cells and mice. MALAT1 silencing or miR-26a-5p upregulation suppressed LPS-induced inflammation and apoptosis of cardiomyocytes in cellular and animal models. These effects of elevated miR-26a-5p could be reversed by upregulating Rcan2, and MALAT1 knockdown-induced ameliorative impacts could be reversed by miR-26a-5p downregulation.

CONCLUSION

MALAT1 silencing elevated miR-26a-5p to ameliorate LPS-induced myocardial injury by reducing Rcan2. Our research may provide novel biomarkers for the treatment of sepsis.

Regulatory Role of Non-Coding RNAs on Immune Responses During Sepsis

Sepsis is resulted from a systemic inflammatory response to bacterial, viral, or fungal agents. The induced inflammatory response by these microorganisms can lead to multiple organ system failure with devastating consequences. Recent studies have shown altered expressions of several non-coding RNAs such as long non-coding RNAs (lncRNAs), microRNAs (miRNAs) and circular RNAs (circRNAs) during sepsis. These transcripts have also been found to participate in the pathogenesis of multiple organ system failure through different mechanisms. NEAT1, MALAT1, THRIL, XIST, MIAT and TUG1 are among lncRNAs that participate in the pathoetiology of sepsis-related complications. miR-21, miR-155, miR-15a-5p, miR-494-3p, miR-218, miR-122, miR-208a-5p, miR-328 and miR-218 are examples of miRNAs participating in these complications. Finally, tens of circRNAs such as circC3P1, hsa_circRNA_104484, hsa_circRNA_104670 and circVMA21 and circ-PRKCI have been found to affect pathogenesis of sepsis. In the current review, we describe the role of these three classes of noncoding RNAs in the pathoetiology of sepsis-related complications.

Resveratrol alleviates sepsis-induced acute kidney injury by deactivating the lncRNA MALAT1/MiR-205 axis

INTRODUCTION

Resveratrol plays a protective role against sepsis development, and the long noncoding RNA (lncRNA) MALAT1 is an inflammation-relevant biomarker. This investigation attempted to reveal whether resveratrol attenuated inflammation of sepsis-induced acute kidney injury (AKI) by regulating MALAT1.

MATERIAL AND METHODS

In total 120 rats were divided into a control group (n = 20), a Sham group (n = 20), a sepsis group (n = 40) and a resveratrol group (n = 40), and serum levels of inflammatory cytokines and AKI biomarkers were determined. An equal number of rats under identical treatments were, additionally, tracked for their survival, and the serum level of lncRNA MALAT1 was measured by RT-PCR. Moreover, septic cell models were constructed by treating HK-2 cells with lipopolysaccharide (LPS), and tumor necrosis factor α (TNF-α), interleukin (IL)-1β, IL-6 levels released by the cells were determined with ELISA.

RESULTS

Resveratrol treatment significantly brought down serum levels of inflammatory cytokines (i.e. TNF-α, IL-1β and IL-6), kidney function indicators (i.e. Scr, blood urea nitrogen [BUN] and Scys C), AKI biomarkers (i.e. NGAL and KIM-1) and MALAT1 in cecal ligation and puncture (CLP)-induced septic model rats (all p < 0.05), and the life span of septic rats was elongated by resveratrol treatment (p < 0.05). Viability and cytokine release of LPS-treated HK2 cells were rescued by resveratrol (p < 0.05), which was accompanied by a marked fall of MALAT1 expression (p < 0.05). In addition, si-MALAT1 diminished viability and suppressed cytokine release of HK2 cells, while pcDNA3.1-MALAT1 hindered the impact of resveratrol on the inflammatory response of HK2 cells (p < 0.05). Ultimately, miR-205, a protective molecule in sepsis-relevant AKI, was down-regulated by resveratrol and si-MALAT1 (p < 0.05).

CONCLUSIONS

Resveratrol relieved sepsis-induced AKI by restraining the lncRNA MALAT1/miR-205 axis.

Long Non-Coding RNAs as Biomarkers and Therapeutic Targets in Sepsis

Sepsis, an infection-induced systemic inflammatory disorder, is often accompanied by multiple organ dysfunction syndromes with high incidence and mortality rates, and those who survive are often left with long-term sequelae, bringing great burden to social economy. Therefore, novel approaches to solve this puzzle are urgently needed. Previous studies revealed that long non-coding RNAs (lncRNAs) have exerted significant influences on the process of sepsis. The aim of this review is to summarize our understanding of lncRNAs as potential sepsis-related diagnostic markers and therapeutic targets, and provide new insights into the diagnosis and treatment for sepsis. In this study, we also introduced the current diagnostic markers of sepsis and discussed their limitations, while review the research advances in lncRNAs as promising biomarkers for diagnosis and prognosis of sepsis. Furthermore, the roles of lncRNAs in sepsis-induced organ dysfunction were illustrated in terms of different organ systems. Nevertheless, further studies should be carried out to elucidate underlying molecular mechanisms and pathological process of sepsis.

Dysregulated lncRNAs are Involved in the Progress of Sepsis by Constructing Regulatory Networks in Whole Blood Cells

Sepsis is a highly heterogeneous syndrome that is caused by an unbalanced host response to an infection. Long noncoding RNAs (lncRNAs) have been reported to exert regulatory roles in a variety of biological processes, and became potential biomarkers and therapeutic targets for diverse diseases. However, current understanding on the roles of lncRNAs in sepsis is extremely limited. Herein, to decipher the underlying functions of lncRNAs, we reexplored the 83 transcriptome datasets from specimens with sepsis, no_sepsis by final diagnosis, and control. The results of differentially expressed genes (DEGs), differentially expressed lncRNA (DElncRNA) analysis, and co-expression analysis of lncRNA–mRNA pairs were obtained. We found that the expression pattern of lncRNAs was significantly activated in sepsis specimens, which was clearly distinguished in sepsis from no_sepsis and control specimens. By performing co-expression analysis, we found DElncRNAs were closely related to T-cell activation and immune response–related terms in sepsis by regulating mRNA expression in the trans manner. The lncRNA–mRNA network and the qRT-PCR test revealed that lncRNAs LINC00861, RP11-284N8.3, and CTB-61M7.2 were significantly correlated with the pathogenesis of sepsis. In addition, weighted gene co-expression analysis (WGCNA) and cis-regulation analysis also revealed sepsis-specific lncRNAs were highly associated with important biological processes correlated with sepsis. In summary, the systematic dysregulation of lncRNAs is tightly involved in the remodeling of gene expression regulatory network in sepsis, and the lncRNA–mRNA expression network may be used to refine biomarker predictions for developing novel therapeutic approaches in sepsis.

Long noncoding RNAs: A potential target in sepsis-induced cellular disorder

Sepsis, an inflammation-related clinical syndrome, is characterized by disrupted immune homeostasis accompanied by infection and multiple organ dysfunction as determined by the Sequential Organ Failure Assessment (SOFA). Substantial evidence has recently suggested that lncRNAs orchestrate various biological processes in diseases, and lncRNAs play special roles in the diagnosis and management of sepsis. To date, very few reviews have provided clear and comprehensive clues to demonstrate the roles of lncRNAs in the pathogenesis of sepsis. Based on previously published studies, in this review, we summarize the different functions of lncRNAs in sepsis-induced cellular disorders and sepsis-induced organ failure to show the potential roles of lncRNAs in the diagnosis and management of sepsis. We further depict the function of some lncRNAs known to be pivotal regulators in the pathogenesis of sepsis to discuss the underlying molecular events. Additionally, we list and discuss several hotspots in research on lncRNAs, which may be conducive to future lncRNA-targeted therapeutic approaches for sepsis treatment.

Knockdown of lncRNA MALAT1 ameliorates acute kidney injury by mediating the miR-204/APOL1 pathway

Background

Acute kidney injury (AKI) was characterized by loss of renal function, associated with chronic kidney disease, end‐stage renal disease, and length of hospital stay. Long non‐coding RNAs (lncRNAs) participated in AKI development and progression. Here, we aimed to investigate the roles and mechanisms of lncRNA MALAT1 in AKI.

Methods

AKI serum samples were obtained from 129 AKI patients. ROC analysis was conducted to confirm the diagnostic value of MALAT1 in differentiating AKI from healthy volunteers. After hypoxic treatment on HK‐2 cells, the expressions of inflammatory cytokines, MALAT1, miR‐204, APOL1, p65, and p‐p65, were measured by RT‐qPCR and Western blot assays. The targeted relationship between miR‐204 and MALAT1 or miR‐204 and APOL1 was determined by luciferase reporter assay and RNA pull‐down analysis. After transfection, CCK‐8, flow cytometry, and TUNEL staining assays were performed to evaluate the effects of MALAT1 and miR‐204 on AKI progression.

Results

From the results, lncRNA MALAT1 was strongly elevated in serum samples from AKI patients, with the high sensitivity and specificity concerning differentiating AKI patients from healthy controls. In vitro, we established the AKI cell model after hypoxic treatment. After experiencing hypoxia, we found significantly increased MALAT1, IL‐1β, IL‐6, and TNF‐α expressions along with decreased miR‐204 level. Moreover, the targeted relationship between MALAT1 and miR‐204 was confirmed. Silencing of MALAT1 could reverse hypoxia‐triggered promotion of HK‐2 cell apoptosis. Meanwhile, the increase of IL‐1β, IL‐6, and TNF‐α after hypoxia treatment could be repressed by MALAT1 knockdown as well. After co‐transfection with MALAT1 silencing and miR‐204 inhibition, we found that miR‐204 could counteract the effects of MALAT1 on HK‐2 cell progression and inflammation after under hypoxic conditions. Finally, NF‐κB signaling was inactivated while APOL1 expression was increased in HK‐2 cells after hypoxia treatment, and lncRNA MALAT1 inhibition reactivated NF‐κB signaling while suppressed APOL1 expression by sponging miR‐204.

Conclusions

Collectively, these results illustrated that knockdown of lncRNA MALAT1 could ameliorate AKI progression and inflammation by targeting miR‐204 through APOL1/NF‐κB signaling.

Clinical application of non-coding RNAs in sepsis

PURPOSE OF REVIEW

Studies indicating that non-coding RNAs (ncRNAs) play a regulatory role in sepsis are increasing rapidly. This present review summarizes recent publications on the role of microRNAs and long non-coding RNAs (lncRNAs) in sepsis.

RECENT FINDINGS

MicroRNAs (miRNAs) and lncRNAs are being identified as potential sepsis biomarkers and therapeutic targets. Experimental studies have examined the biological mechanisms that might underpin the regulatory role of these ncRNAs in sepsis.

SUMMARY

Clinical applications of miRNAs and lncRNAs in sepsis are on the horizon. These data could lead to the identification of novel treatments or indeed support the repurposing of existing drugs for sepsis. Validation of the findings from these preliminary studies and crucially integration of multiomics datasets will undoubtedly revolutionize the clinical management of sepsis.

Long Noncoding RNA: Regulatory Mechanisms and Therapeutic Potential in Sepsis

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection and is characterized by a hyperinflammatory state accompanied by immunosuppression. Long noncoding RNAs (lncRNAs) are noncoding RNAs longer than 200 nucleotides and have important roles in mediating various biological processes. Recently, lncRNAs were found to exert both promotive and inhibitory immune functions in sepsis, thus participating in sepsis regulation. Additionally, several studies have revealed that lncRNAs are involved in sepsis-induced organ dysfunctions, including cardiovascular dysfunction, acute lung injury, and acute kidney injury. Considering the lack of effective biomarkers for early identification and specific treatment for sepsis, lncRNAs may be promising biomarkers and even targets for sepsis therapies. This review systematically highlights the recent advances regarding the roles of lncRNAs in sepsis and sheds light on their use as potential biomarkers and treatment targets for sepsis.

Long noncoding RNA GAS8-AS1: A novel biomarker in human diseases

Long non-coding RNAs (lncRNAs) represent a group of ncRNAs with more than 200 nucleotides. These RNAs can specifically regulate gene expression at both the transcriptional and the post-transcriptional levels, and increasing evidence indicates that they play vital roles in a variety of disease-related cellular processes. The lncRNA GAS8 antisense RNA 1 (GAS8-AS1, also known as C16orf3) is located in the second intron of GAS8 and has been reported to be both abnormally expressed in several diseases and closely correlated with many clinical characteristics. GAS8-AS1 has been shown to affect many biological functions, including cell proliferation, migration, invasiveness, and autophagy using several signaling pathways. In this review, we have summarized current studies on GAS8-AS1 roles in disease and discuss its potential clinical utility. GAS8-AS1 may be a promising biomarker for both diagnoses and prognoses, and a novel target for many disease therapies.

MicroRNA-150 affects endoplasmic reticulum stress via MALAT1-miR-150 axis-mediated NF-κB pathway in LPS-challenged HUVECs and septic mice

AIMS

Sepsis is a systemic inflammatory complication, which is the common cause of death in critical patients. This study aimed to evaluate the potential regulatory mechanisms of miR-150 in lipopolysaccharide (LPS)-challenged HUVECs and cecal ligation and puncture (CLP)-induced septic mice.

MATERIALS AND METHODS

Human umbilical vein endothelial cells (HUVECs) were challenged with LPS. Pulmonary arterial endothelial cells (PAECs) were isolated from CLP-induced septic mice. The mRNA and protein levels of target molecules were detected by RT-qPCR and Western blotting. Apoptosis of HUVECs was determined by Annexin V/PI staining on a flow cytometry. The interaction between miR-150 and MALAT1 was assessed by luciferase reporter assay, RIP and RNA pull-down assay.

KEY FINDINGS

MiR-150 was downregulated in LPS-induced HUVECs. MiR-150 mimics restrained LPS-induced inflammatory response by reducing TNF-α and IL-6 levels, but increasing IL-10 level. Moreover, miR-150 mimics downregulated endoplasmic reticulum (ER) stress-related proteins, GRP78 and CHOP levels in LPS-exposed HUVECs. Additionally, LPS-induced apoptosis was suppressed by miR-150 mimics via decreasing cleaved caspase-3 and Bax levels, while enhancing Bcl-2 level. Mechanistically, MALAT1 could competitively bind to miR-150. LPS-induced apoptosis, ER stress and inflammation were promoted by MALAT1 overexpression, but reversed by siMALAT1. Furthermore, miR-150 inhibitor strengthened LPS-induced apoptosis, ER stress and inflammation, which could be attenuated by siMALAT1 via regulating NF-κB pathway. Finally, agomiR-150 repressed ER stress and inflammatory response in PAECs isolated from septic mice via decreasing MALAT1 level.

SIGNIFICANCE

Our findings suggest that miR-150 affects sepsis-induced endothelial injury by regulating ER stress and inflammation via MALAT1-mediated NF-κB pathway.

MicroRNA-146b correlates with decreased acute respiratory distress syndrome risk, reduced disease severity, and lower 28-day mortality in sepsis patients

Objective

This study aimed to investigate the predictive value of microRNA‐146b (miR‐146b) on acute respiratory distress syndrome (ARDS) risk, and the correlation of miR‐146b with disease severity and 28‐day mortality in sepsis patients.

Methods

A total of 104 sepsis patients and 100 healthy controls (HCs) were consecutively enrolled, and miR‐146b relative expression in their plasma samples was detected by reverse transcription‐quantitative polymerase chain reaction. In sepsis patients, disease severity was assessed using Acute Physiology and Chronic Health Evaluation II (APACHE II) score and Sequential Organ Failure Assessment (SOFA) score. ARDS occurrence and 28‐day mortality were recorded.

Results

MiR‐146b was decreased in sepsis patients compared to HCs. ARDS occurred in 30 (28.8%) sepsis patients, and miR‐146b was reduced in ARDS sepsis patients compared to non‐ARDS sepsis patients. Meanwhile, miR‐146b distinguished ARDS sepsis patients from non‐ARDS sepsis patients (area under the curve (AUC): 0.728, 95% confidence interval (CI): 0.627‐0.829). Subsequent multivariate logistic regression showed that miR‐146b, age, smoke, respiratory infection, and serum creatinine predicted ARDS risk independently, and their combination well‐discriminated ARDS sepsis patients from non‐ARDS sepsis patients (AUC: 0.863, 95% CI: 0.792‐0.934). Additionally, miR‐146b was negatively correlated with serum creatinine, white blood cell, C‐reactive protein, APACHE II score, and SOFA score, while positively correlated with albumin. Regarding prognosis, miR‐146b was decreased in 28‐day sepsis deaths compared to 28‐day sepsis survivors, and it discriminated 28‐day sepsis deaths from 28‐day sepsis survivors (AUC: 0.785, 95% CI: 0.680‐0.890).

Conclusion

MiR‐146b might serve as a potential biomarker for ARDS prevention and prognostic reflection in sepsis.

The value of circulating long non-coding RNA maternally expressed gene 3 as a predictor of higher acute respiratory distress syndrome risk and 28-day mortality in sepsis patients

Objective

This study was to evaluate the potential of long non‐coding RNA maternally expressed gene 3 (lncRNA MEG3) in predicting acute respiratory distress syndrome (ARDS) risk and its correlation with prognosis in sepsis patients.

Methods

The plasma samples were obtained from 112 sepsis patients within 24 hours after admission and 100 healthy controls (HCs) at enrollment. The lncRNA MEG3 expression in plasma samples was determined by RT‐qPCR. In sepsis patients, ARDS occurrence was assessed based on Berlin definition of ARDS and 28‐day mortality risk was evaluated.

Results

LncRNA MEG3 expression was increased in sepsis patients compared with HCs. During 28‐day duration, 30 sepsis patients occurred ARDS and 82 sepsis patients did not occur ARDS. LncRNA MEG3 expression was elevated in ARDS sepsis patients compared with non‐ARDS sepsis patients, then the following receiver‐operating characteristic (ROC) curve analysis disclosed that lncRNA MEG3 predicted ARDS risk (area under the curve (AUC) = 0.775), which was further validated as an independent risk factor by multivariate logistic regression. Furthermore, lncRNA MEG3 was positively correlated with chronic obstructive pulmonary disease, respiratory infection, acute physiology and chronic health evaluation II score, sequential organ failure assessment score, white blood cell, and C‐reactive protein, while negatively correlated with albumin in sepsis patients. Additionally, lncRNA MEG3 was elevated in 28‐day deaths compared with 28‐day survivors, and it predicted 28‐day mortality risk in sepsis patients (AUC = 0.708) by ROC curve analysis.

Conclusion

LncRNA MEG3 might represent as a valuable biomarker for individualizing prevention strategies against ARDS and improving prognosis in sepsis.

LncRNA NEAT1 promotes apoptosis and inflammation in LPS-induced sepsis models by targeting miR-590-3p

Sepsis is a complication of infection caused by disease or trauma. Increasing evidence have shown that long noncoding RNAs (lncRNAs) are involved in the regulation of sepsis. However, the mechanism of lncRNA nuclear enriched abundant transcript 1 (NEAT1) in the regulation of sepsis progression remains to be elucidated. Lipopolysaccharide (LPS) was used to induce a sepsis cell model. The expression levels of NEAT1 and microRNA (miR)-590-3p were determined by reverse transcription-quantitative PCR. Cell viability and apoptosis were detected using Cell Counting Kit-8 (CCK-8) assay and flow cytometry, respectively. Western blot analysis was performed to evaluate the levels of apoptosis- and NF-κB signaling pathway-related proteins. The concentration of inflammatory cytokines was determined using ELISA. In addition, dual-luciferase reporter assay, RNA immunoprecipitation and biotin-labeled RNA pull-down assay were performed to verify the interaction between NEAT1 and miR-590-3p. The results showed that NEAT1 was highly expressed in patients with sepsis and LPS-induced H9c2 cells. Knockdown of NEAT1 decreased LPS-induced cell apoptosis and inflammation response in H9c2 cells. Meanwhile, miR-590-3p showed decreased expression in sepsis, and its overexpression could relieve LPS-induced H9c2 cell damage. Further experiments revealed that NEAT1 could sponge miR-590-3p. Knockdown of miR-590-3p reversed the inhibitory effect of NEAT1 knockdown on LPS-induced H9c2 cell damage. Additionally, the NEAT1/miR-590-3p axis could regulate the activity of the NF-κB signaling pathway. To conclude, lncRNA NEAT1 accelerated apoptosis and inflammation in LPS-stimulated H9c2 cells via sponging miR-590-3p. These findings may provide a new strategy for the treatment of sepsis.

The clinical value of lncRNA MALAT1 and its targets miR-125b, miR-133, miR-146a, and miR-203 for predicting disease progression in chronic obstructive pulmonary disease patients

Objective

The study aimed to explore the correlations of long non‐coding RNA MALAT1 (lncRNA MALAT1) and its targets microRNA (miR)‐125b, miR‐133, miR‐146a, and miR‐203 with acute exacerbation risk, inflammation, and disease severity of chronic obstructive pulmonary disease (COPD).

Methods

Plasma samples were obtained from 120 acute exacerbation COPD (AECOPD) patients, 120 stable COPD patients, and 120 healthy controls (HCs). RT‐qPCR was conducted to detect lncRNA MALAT1 expression and its target miRNAs, and ELISA was performed to detect the inflammatory cytokines.

Results

LncRNA MALAT1 was highest in AECOPD patients followed by stable COPD patients and then HCs, which distinguished AECOPD patients from HCs (AUC: 0.969, 95% CI: 0.951‐0.987) and stable COPD patients (AUC: 0.846, 95% CI: 0.798‐0.894). Furthermore, lncRNA MALAT1 positively correlated with GOLD stage in both AECOPD and stable COPD patients. Regarding inflammatory cytokines, lncRNA MALAT1 positively correlated with tumor necrosis factor‐α (TNF‐α), interleukin (IL)‐1β, IL‐6, IL‐8, IL‐17, and IL‐23 in both AECOPD and stable COPD patients. Besides, lncRNA MALAT1 negatively correlated with miR‐125b, miR‐146a, and miR‐203 in AECOPD patients and reversely correlated with miR‐125b and miR‐146a in stable COPD patients. Notably, miR‐125b, miR‐133, miR‐146a, and miR‐203 were the lowest in AECOPD patients, followed by stable COPD patients, and then HCs; miR‐125b, miR‐133, miR‐146a, and miR‐203 negatively correlated with inflammation and GOLD stage in AECOPD and stable COPD patients.

Conclusion

LncRNA MALAT1 exhibits clinical implications in acute exacerbation risk prediction and management of COPD via the inner‐correlation with its targets miR‐125b, miR‐146a, and miR‐203.

A Novel lncRNA NONHSAT053785 Acts as an Independent Risk Factor for Intrahepatic Metastasis of Hepatocellular Carcinoma

Purpose

Long noncoding RNAs (lncRNAs) in body fluids have been considered as promising novel biomarkers for tumor-related diseases. The present study aimed to investigate the expression level of lncRNA NONHSAT053785 in serum and its correlation with clinical characteristics of hepatocellular carcinoma (HCC) patients.

Methods

The droplet digital PCR (ddPCR) was used to measure the serum levels of NONHSAT053785 in 112 HCC patients, 96 chronic hepatitis B (CHB) patients, and 99 healthy controls (HC). The correlation between NONHSAT053785 and clinical characteristics was analyzed by chi-square test and Spearman correlation test. The risk factors of intrahepatic metastasis (IM) were detected by univariate and multivariate analyses. Furthermore, the diagnostic value of NONHSAT053785 in HCC and its predictive ability in IM were evaluated by the receiver operating characteristic (ROC) curves.

Results

The level of NONHSAT053785 was significantly increased in the serum of HCC patients and was higher in HCC patients with IM as compared to those without. Additionally, the expression level of NONHSAT053785 was significantly related to IM, Child–Pugh classification, and peripheral blood indicators such as liver metabolic enzymes and positively correlated to IM, Barcelona Clinic Liver Cancer (BCLC) staging, and some peripheral blood indicators. Furthermore, the serum NONHSAT053785 was indicated as an independent predictor for IM in the elderly, non-smoking, drinking, and tumor size ≥5 cm subjects. The area under the ROC curve (AUC) was 0.801 (P <0.0001) for diagnosis of HCC and 0.678 (P =0.0015) for predicting IM.

Conclusion

The increase in serum NONHSAT053785 levels was related to an increased risk of IM, and hence, may serve as a novel biomarker for the diagnosis of HCC and the prediction of IM.

Long non-coding RNA MALAT1/microRNA 125a axis presents excellent value in discriminating sepsis patients and exhibits positive association with general disease severity, organ injury, inflammation level, and mortality in sepsis patients

Objective

The present study aimed to investigate the potential value of long non‐coding RNA metastasis‐associated lung adenocarcinoma transcript 1 (lnc‐MALAT1)/microRNA (miR)‐125a axis in disease management and prognosis surveillance of sepsis.

Methods

Totally, 196 sepsis patients and 196 healthy controls were enrolled. Blood samples were collected within 24 hours after admission in sepsis patients and were collected at enrollment in healthy controls. The relative expression of lnc‐MALAT1 and miR‐125a in all participants was detected by reverse transcription quantitative polymerase chain reaction, and the inflammatory cytokines in plasma of sepsis patients were measured by enzyme‐linked immunosorbent assay.

Results

Lnc‐MALAT1/miR‐125a axis was increased in sepsis patients compared with healthy controls (P < .001) and was of excellent value in distinguishing septic patients from healthy controls with the area under the curve (AUC) of 0.931 (95% CI: 0.908‐0.954). In sepsis patients, lnc‐MALAT1 was negatively associated with miR‐125a, and lnc‐MALAT1/miR‐125a axis was positively correlated with acute pathologic and chronic health evaluation II (APACHE II) score, Sequential Organ Failure Assessment (SOFA) score, serum creatinine, C‐reactive protein, tumor necrosis factor‐α, interleukin (IL)‐1β, IL‐6, and IL‐8, while negatively associated with albumin. Furthermore, lnc‐MALAT1/miR‐125a axis was of value in predicting increased 28‐day mortality risk to some extent (AUC: 0.678, 95% CI: 0.603‐0.754).

Conclusion

Lnc‐MALAT1/miR‐125a axis presents excellent value in differentiating sepsis patients from healthy controls and also exhibits positive association with general disease severity, organ injury, inflammation level, and mortality in sepsis patients.

Potential role of circulating long noncoding RNA MALAT1 in predicting disease risk, severity, and patients' survival in sepsis

Background

This study aimed to investigate the plasma long noncoding RNA metastasis‐associated lung adenocarcinoma transcript 1 (lncRNA MALAT1) expression with risk, severity, inflammation level, and prognosis in sepsis.

Methods

One hundred and ninety sepsis patients and 190 health controls (HCs) were consecutively recruited. Blood samples within 24 hours after admission of sepsis patients and those on enrollment of HCs were collected, and then, plasma was separated for lncRNA MALAT1 and miR‐125b expressions detections by RT‐qPCR. In sepsis patients, clinical data and 28‐day mortality were recorded, and plasma inflammatory cytokines expressions were detected by ELISA.

Results

Plasma lncRNA MALAT1 expression was elevated in sepsis patients than HCs (P < 0.001), and ROC curve disclosed that it had a good value in predicting sepsis risk with an area under curve (AUC) of 0.823 (95% CI: 0.783‐0.864). Additionally, lncRNA MALAT1 expression was positively correlated with Scr (P = 0.005), WBC (P = 0.017), CRP (P < 0.001), PCT (P < 0.001), TNF‐α (P < 0.001), IL‐8 (P < 0.001), IL‐17 (P = 0.001), APACHE II score (P < 0.001), and SOFA score (P < 0.001). LncRNA MALA1 expression was elevated in deaths compared with survivors (P < 0.001) and could predict the risk of 28‐day mortality with an AUC of 0.755 (95% CI: 0.682‐0.828). Accumulating survival was worse in patients with lncRNA MALAT1 high expression compared with patients who had lncRNA MALAT1 low expression (P < 0.001). Moreover, lncRNA MALAT1 expression was negatively correlated with miR‐125b level in both sepsis patients (P < 0.001) and HCs (P < 0.001).

Conclusion

LncRNA MALAT1 could be developed as a potential biomarker for facilitating diagnosis and management in sepsis patients.