Lnc-MEG3 acts as a potential biomarker for predicting increased disease risk, systemic inflammation, disease severity, and poor prognosis of sepsis via interacting with miR-21

LncRNA MEG3 suppresses hepatocellular carcinoma by stimulating macrophage M1 polarization and modulating immune system via inhibiting CSF-1 in vivo/vitro studies

Hepatocellular carcinoma (HCC) is characterized by a complex tumor microenvironment (TME), and long non-coding RNAs (lncRNAs) MEG3 emerged as regulators of macrophage polarization with a negative relationship with colony-stimulating factor 1 (CSF-1). Few studies are on the interplay among MEG3, CSF-1, T helper cells (Th), and the programmed cell death protein 1 and its ligands (PD-1/PD-Ls) in TME of HCC.MEG3 expression in THP-1 macrophages, monitored polarization, and PD-1/PD-Ls expression were through flow cytometry, WB, and RT-qPCR. In co-cultures, the interaction of MEG3, macrophage, and HCC was assayed by ELISA. The invasive and migratory of HCC were assessed through experiments such as CCK-8, clonogenic assay, wound healing, and Transwell. A xenograft mouse model of HCC was established, administered with MEG3 overexpression (OE) or knockdown (KD) constructs, and monitored tumor growth. In vitro, MEG3 OE induced a robust M1 macrophage phenotype, evidenced by elevated expression of M1 markers and a significant increase in Th1 cytokines, with a concomitant decrease in Th2 cytokines. This was paralleled by reduced CSF-1 and PD-1/PD-Ls expression. In contrast, MEG3 KD promoted an M2 phenotype with increased CSF-1 and PD-1/PD-Ls expression, and an upregulation of Th2 cytokines. MEG3 OE inhibited the growth, invasion, and migration of HCC, while the opposite was observed when MEG3 was downregulated. In vivo, MEG3 OE resulted in significantly reduced tumor growth, with decreased PD-1/PD-Ls expression on macrophages and enhanced Th1 response. Conversely, MEG3 KD promoted tumor growth with increased PD-1/PD-Ls and a Th2-skewed immune response. MEG3 modulates the TME by affecting TAMs through CSF-1, thereby influencing the balance of Th1/Th2 cells and altering the expression of PD-1/PD-L1s. This study demonstrates that targeting MEG3 is an effective therapeutic strategy for HCC.

Long non-coding RNA small nucleolar RNA host gene 8 (SNHG8) sponges miR-34b-5p to prevent sepsis-induced cardiac dysfunction and inflammation and serves as a diagnostic biomarker

Introduction

The study aimed to evaluate, for the first time, the diagnostic value of long non-coding RNA (lncRNA) small nucleolar RNA host gene 8 (SNHG8) in sepsis and its molecular mechanisms in sepsis-induced inflammation and cardiac dysfunction.

Material and methods

A total of 126 sepsis patients and 81 healthy controls were enrolled. Serum SNHG8 levels were assessed by RT-qPCR. Levels of pro-inflammatory factors were examined via ELISA. The ROC curve was employed to assess the diagnostic significance of SNHG8. Cardiomyocytes were exposed to lipopolysaccharide (LPS) to simulate sepsis-induced cardiac dysfunction in vitro. Cell proliferation and apoptosis were measured through CCK-8 and flow cytometry. Dual luciferase reporter gene assay and RIP assay were conducted to verify the target relationship between SNHG8 and miR-34b-5p.

Results

SNHG8 was reduced in sepsis patients (p < 0.05) and negatively correlated with procalcitonin, C-reactive protein, and pro-inflammatory factors (p < 0.05). SNHG8 had outstanding performance in distinguishing sepsis patients from healthy individuals with the AUC of 0.878. Among septic patients, those with cardiac dysfunction had significantly downregulated SNHG8 levels (p < 0.05). For septic patients, SNHG8 was found to be an independent predictor for the occurrence of cardiac dysfunction (HR = 5.466, 95% CI = 2.230-13.397, p < 0.001). Elevated SNHG8 reversed LPS-induced cell apoptosis, and attenuated the over-secretion of inflammatory factors. miR-34b-5p was significantly upregulated in septic patients and negatively correlated with SNHG8, indicating that it acted as a sponge for SNHG8.

Conclusions

Reduced SNHG8 is a potential diagnostic biomarker for sepsis. It is involved in sepsis-induced inflammatory response and cardiac dysfunction through sponging miR-34b-5p.

Sepsis Biomarkers: Advancements and Clinical Applications-A Narrative Review

Sepsis is now defined as a life-threatening syndrome of organ dysfunction triggered by a dysregulated host response to infection, posing significant challenges in critical care. The main objective of this review is to evaluate the potential of emerging biomarkers for early diagnosis and accurate prognosis in sepsis management, which are pivotal for enhancing patient outcomes. Despite advances in supportive care, traditional biomarkers like C-reactive protein and procalcitonin have limitations, and recent studies have identified novel biomarkers with increased sensitivity and specificity, including circular RNAs, HOXA distal transcript antisense RNA, microRNA-486-5p, protein C, triiodothyronine, and prokineticin 2. These emerging biomarkers hold promising potential for the early detection and prognostication of sepsis. They play a crucial role not only in diagnosis but also in guiding antibiotic therapy and evaluating treatment effectiveness. The introduction of point-of-care testing technologies has brought about a paradigm shift in biomarker application, enabling swift and real-time patient evaluation. Despite these advancements, challenges persist, notably concerning biomarker variability and the lack of standardized thresholds. This review summarizes the latest advancements in sepsis biomarker research, spotlighting the progress and clinical implications. It emphasizes the significance of multi-biomarker strategies and the feasibility of personalized medicine in sepsis management. Further verification of biomarkers on a large scale and their integration into clinical practice are advocated to maximize their efficacy in future sepsis treatment.

Hippocampal adenosine-to-inosine RNA editing in sepsis: dynamic changes and influencing factors

Sepsis-associated encephalopathy is a diffuse brain dysfunction secondary to infection. It has been established that factors such as age and sex can significantly contribute to the development of sepsis-associated encephalopathy. Our recent study implicated a possible link between adenosine-to-inosine RNA editing and sepsis-associated encephalopathy, yet the dynamics of adenosine-to-inosine RNA editing during sepsis-associated encephalopathy and how it could be influenced by factors such as age, sex and antidepressants remain uninvestigated. Our current study analysed and validated transcriptome-wide changes in adenosine-to-inosine RNA editing in the hippocampus of different septic mouse models. Seventy-four sites in 64 genes showed significant differential RNA editing over time in septic mice induced by caecal ligation and perforation. The differential RNA editing might contribute to the RNA expression regulation of the edited genes, with 42.2% differentially expressed. These differentially edited genes, especially those with missense editing, such as glutamate receptor, ionotropic, kainate 2 (Grik2, p.M620V), filamin A (Flna, p.S2331G) and capicua transcriptional repressor (Cic, p.E2270G), were mainly involved in abnormal social behaviour and neurodevelopmental and psychiatric disorders. Significant effects of age and sex were also observed on sepsis-associated RNA editing. Further comparison highlighted 40 common differential RNA editing sites that caecal ligation and perforation-induced and lipopolysaccharide-induced septic mouse models shared. Interestingly, these findings demonstrate temporal dynamics of adenosine-to-inosine RNA editing in the mouse hippocampus during sepsis, add to the understanding of age and sex differences in the disease and underscore the role of the epigenetic process in sepsis-associated encephalopathy.

Early Diagnosis of Sepsis: The Role of Biomarkers and Rapid Microbiological Tests

Sepsis is a medical emergency resulting from a dysregulated response to an infection, causing preventable deaths and a high burden of morbidity. Protocolized and accurate interventions in sepsis are time-critical. Therefore, earlier recognition of cases allows for preventive interventions, early treatment, and improved outcomes. Clinical diagnosis of sepsis by clinical scores cannot be considered an early diagnosis, given that underlying molecular pathophysiological mechanisms have been activated in the preceding hour or days. There is a lack of a widely available tool enhancing preclinical diagnosis of sepsis. Sophisticated technologies for sepsis prediction have several limitations, including high costs. Novel technologies for fast molecular and microbiological diagnosis are focusing on bedside point-of-care combined testing to reach most settings where sepsis represents a challenge.

Navigating the Modern Landscape of Sepsis: Advances in Diagnosis and Treatment

Sepsis poses a significant threat to human health due to its high morbidity and mortality rates worldwide. Traditional diagnostic methods for identifying sepsis or its causative organisms are time-consuming and contribute to a high mortality rate. Biomarkers have been developed to overcome these limitations and are currently used for sepsis diagnosis, prognosis prediction, and treatment response assessment. Over the past few decades, more than 250 biomarkers have been identified, a few of which have been used in clinical decision-making. Consistent with the limitations of diagnosing sepsis, there is currently no specific treatment for sepsis. Currently, the general treatment for sepsis is conservative and includes timely antibiotic use and hemodynamic support. When planning sepsis-specific treatment, it is important to select the most suitable patient, considering the heterogeneous nature of sepsis. This comprehensive review summarizes current and evolving biomarkers and therapeutic approaches for sepsis.

Long non‑coding RNAs MALAT1, NEAT1 and DSCR4 can be serum biomarkers in predicting urosepsis occurrence and reflect disease severity

Sepsis commonly occurs in patients with serious infections. It severely threatens the health of patients and has very high mortality rates. Urosepsis is a type of sepsis in which the serious infection originates from the urinary system. Early diagnosis of the occurrence and severity of urogenital sepsis is crucial for improving patient prognosis. Long noncoding RNAs (LncRNAs) play important roles in the occurrence of a number of diseases, including sepsis, and can be potential biomarkers that predict disease development. The present study aimed to discover potential LncRNAs that can predict the occurrence of urosepsis. RNA-sequence data from patients with sepsis from the GEO database was analyzed and LncRNAs associated with sepsis were identified. The expression of LncRNAs associated with sepsis was tested in clinical urosepsis samples. Finally, the value of these LncRNAs in predicting urosepsis was verified using clinical samples. From the GEO database a total of nine LncRNAs (MALAT1, NEAT1, RMRP, LncIRX5, LINC01742, DSCR4, C22ORF34, LINC00381, and LINC01102) were identified that had expression changes corresponding with the occurrence of sepsis. Specifically, MALAT1, NEAT1 and DSCR4 revealed differential expression in patients with urosepsis. Moreover, MALAT1, and DSCR4 were shown to be significant risk indicators for urosepsis, and NEAT1 was shown to reflect disease severity. Therefore, the present study indicated that the LncRNAs, MALAT1, NEAT1 and DSCR4 can reflect the occurrence and severity of urosepsis and may act as potential biomarkers.

Expression pattern of long non-coding RNAs MALAT1 and MEG3 in COVID-19 patients

BACKGROUND

COVID-19 is a novel infectious disease for which no specific treatment exists. It is likely that a combination of genetic and non-genetic factors predispose to it. Expression levels of genes that are involved in the interaction with SARS-CoV-2 or the host response are thought to play a role in disease susceptibility and severity. It is crucial to explore biomarkers for disease severity and outcome. Herein, we studied the expression levels and effects of long non-coding metastasis-associated lung adenocarcinoma transcript 1 (lnc-MALAT1) and long non-coding maternally expressed gene 3 (lnc-MEG3) in COVID-19 patients. The study enrolled 35 hospitalized and 35 non-hospitalized COVID-19 patients, and 35 healthy controls. A chest computed tomography (CT) scan, complete blood count (CBC), ferritin, C-reactive protein (CRP), D-dimer and analysis of lnc-MALAT1 and lnc-MEG3 expression were done.

RESULTS

There was a significant relation between ferritin, CRP, D-dimer levels, oxygen saturation, CT-CORADS score and disease severity. Lnc-MALAT1 was significantly higher but lnc-MEG3 was significantly lower in patients vs. controls, and in hospitalized vs. non-hospitalized patients. Elevated MALAT1 and reduced MEG3 levels were significantly associated with more elevated ferritin, CRP, D-dimer levels, lower oxygen saturation, higher CT-CORADS score and poor survival. Moreover, MALAT1 and MEG3 levels displayed higher sensitivity and specificity as predictors of COVID-19 severity compared with other prognostic biochemical markers such as ferritin, CRP, and D-dimer.

CONCLUSIONS

MALAT1 levels are higher, whereas MEG3 levels are lower in COVID-19 patients. Both are linked to disease severity and mortality and could emerge as predictive biomarkers for COVID-19 severity and therapeutic targets.

lncRNA DHFRL1‑4 knockdown attenuates cerebral ischemia/reperfusion injury by upregulating the levels of angiogenesis‑related genes

The present study aimed to investigate the effects of long non-coding (lncRNA) dihydrofolate reductase-like 1 (DHFRL1-4) on cerebral ischemia/reperfusion (I/R)-induced injury. For this purpose, mice injected with lentivirus with small interfering RNA targeting DHFRL1-4 or negative control siRNA were used to construct models of cerebral I/R injury. Following the establishment of the model, the infarct size, neurological deficit score, apoptosis and the expression levels of basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), Wnt family member 3a (Wnt3a), glycogen synthase kinase-3β (GSK-3β) and phosphorylated GSK-3β were assessed. The expression of DHFRL1-4 was significantly upregulated in the I/R model. In the control and sham groups, the boundaries between the cortex and gray matter were clear, and no edema or necrosis were observed. The nerve cells were arranged orderly and evenly, and the cell membranes were intact with visible nucleus and nucleolus. In the model group however, the nerve fibers were slightly necrotic and swollen, and the number of nerve cells was reduced. In the mice injected with si-DHFRL1-4 lentivirus, the brain tissues exhibited less liquefaction and degeneration, as well as less edema. Compared with the control and sham groups, the model group had a significantly larger infarct area, a higher apoptotic rate, higher bFGF, VEGF, Wnt3a and GSK-3β expression levels and a greater neurological deficit score. However, the mice injected with si-DHFRL1-4 lentivirus exhibited a significantly reduced infarct area, a lower apoptotic rate, lower Wnt3a and GSK-3β expression levels, a lower neurological deficit score, and significantly upregulated bFGF and VEGF levels.

miR-21 Regulates Immune Balance Mediated by Th17/Treg in Peripheral Blood of Septic Rats during the Early Phase through Apoptosis Pathway

Objective

To study the mechanism by which miR-21 regulates the differentiation and function of Th17/Treg cells in sepsis.

Methods

A rat model with sepsis was made by cecal ligation and puncture (CLP). Then, some of the septic rats were transfected with miR-21 mimic or inhibitor by liposome. At 48 hours, lymphocytes and plasma from septic rats were isolated for further experimental detection. The expression of miR-21 in lymphocytes was detected by Polymerase Chain Reaction (PCR); the differentiation of Th17/Treg cells was counted by flow cytometry; lymphocyte apoptosis was observed by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay. The caspase-3/9 proteins were tested by Western blot; IL-10 and IL-17 were detected by enzyme-linked immunosorbent assay (ELISA).

Results

Compared with the sepsis group (SP group), the Th17 cells increased significantly, the Treg cells decreased significantly, the apoptosis rate of lymphocytes decreased significantly, the mRNA and proteins of caspase-3/9 decreased significantly, the IL-17 decreased, and the IL-10 increased in the sepsis group transfected with miR-21 (SP + miR-21 mimic group). After transfection of miR-21 inhibitor, the results were almost opposite to those of SP + miR-21 mimic group.

Conclusions

The differentiation and function of Th17/Treg cells were regulated by miR-21 in sepsis through caspase pathway.

Biomarkers for sepsis: more than just fever and leukocytosis-a narrative review

A biomarker describes a measurable indicator of a patient's clinical condition that can be measured accurately and reproducibly. Biomarkers offer utility for diagnosis, prognosis, early disease recognition, risk stratification, appropriate treatment (theranostics), and trial enrichment for patients with sepsis or suspected sepsis. In this narrative review, we aim to answer the question, "Do biomarkers in patients with sepsis or septic shock predict mortality, multiple organ dysfunction syndrome (MODS), or organ dysfunction?" We also discuss the role of pro- and anti-inflammatory biomarkers and biomarkers associated with intestinal permeability, endothelial injury, organ dysfunction, blood-brain barrier (BBB) breakdown, brain injury, and short and long-term mortality. For sepsis, a range of biomarkers is identified, including fluid phase pattern recognition molecules (PRMs), complement system, cytokines, chemokines, damage-associated molecular patterns (DAMPs), non-coding RNAs, miRNAs, cell membrane receptors, cell proteins, metabolites, and soluble receptors. We also provide an overview of immune response biomarkers that can help identify or differentiate between systemic inflammatory response syndrome (SIRS), sepsis, septic shock, and sepsis-associated encephalopathy. However, significant work is needed to identify the optimal combinations of biomarkers that can augment diagnosis, treatment, and good patient outcomes.

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.

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.

The relationship of long non-coding RNA maternally expressed gene 3 with microRNA-21 and their correlation with acute ischemic stroke risk, disease severity and recurrence risk

OBJECTIVE

Long non-coding RNA maternally expressed gene 3 (lnc-MEG3) directly targets microRNA-21 (miR-21) to regulate the vascular microenvironment, and is closely implicated in the pathology of acute ischemic stroke (AIS). However, no research regarding the interaction of lnc-MEG3 and miR-21 in AIS patients has been conducted, to the best of our knowledge. Therefore, we performed this study to evaluate the correlation of lnc-MEG3 with miR-21, and to explore their clinical role for AIS management.

METHODS

A total of 170 AIS patients and 100 controls with at least two high-risk factors for stroke were enrolled. The expression of lnc-MEG3 and miR-21 in peripheral blood mononuclear cells was detected by reverse transcription-quantitative polymerase chain reaction.

RESULTS

Lnc-MEG3 expression was increased in AIS patients and could differentiate AIS patients from controls using receiver operating characteristic (ROC) curve analysis with area under the curve (AUC) of 0.874 and a 95% confidence interval (CI) of 0.833-0.914. Lnc-MEG3 expression was positively correlated with tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-17A and the National Institutes of Health Stroke Scale (NIHSS) score, and its high expression was also correlated with elevated accumulating recurrence rate in AIS patients. In addition, lnc-MEG3 expression was negatively correlated with miR-21 expression in AIS patients. Regarding miR-21, it was reduced in AIS patients and could differentiate AIS patients from controls with AUC of 0.889 (95% CI: 0.850-0.927). Also, miR-21 expression was negatively correlated with TNF-α, IL-17A, NIHSS score and accumulating recurrence rate in AIS patients.

CONCLUSION

Lnc-MEG3 is negatively correlated with miR-21, and both factors are related to disease risk, inflammatory cytokines, disease severity and recurrence risk of AIS.

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.

miR-486-5p Serves as a Diagnostic Biomarker for Sepsis and Its Predictive Value for Clinical Outcomes

Background

As a molecular detection method, miRNA can quickly diagnose and prevent diseases, intervene in disease as early as possible, and reduce mortality. This study was to investigate the potential clinical diagnostic and predictive significance of miR-486-5p in sepsis and its correlation with inflammation and disease severity.

Methods

The serum miR-486-5p in 108 sepsis, 60 pneumonia-infected, and 101 healthy controls were detected by RT-qPCR. Spearman coefficient detects the correlation between serum miRNA and disease severity indicators (APACHE II, SOFA scores), and inflammation indicators (CRP, PCT), respectively. The diagnostic significance of miR-486-5p in sepsis was analyzed by the ROC curve. Kaplan–Meier estimator and Cox regression hazards analysis of the predictive significance of serum miR-486-5p in 28-day survival from sepsis.

Results

Serum miR-486-5p was increased in sepsis patients compared with healthy control and pneumonia-infected patients (P < 0.001). And increased serum miR-486-5p was positively associated with disease severity (SOFA score and APACHE II score) and inflammation (CRP and PCT). Serum miR-486-5p can not only identify sepsis patients from healthy controls (AUC = 0.914) but also significantly distinguish sepsis patients from pneumonia-infected patients (AUC = 0.814), showing good potential as a diagnostic biomarker for sepsis. In addition, serum miR-486-5p was an independent predictor of 28-day survival (log-rank P = 0.012), and patients with high levels of miR-486-5p had a poorer overall 28-day survival (HR = 3.057, 95% CI = 1.385–17.817, P = 0.014).

Conclusion

miR-486-5p is a potential diagnostic biomarker for sepsis, and its high level is significantly correlated with the disease severity and inflammation. In addition, miR-486-5p were predictive risk factors for 28-day survival in sepsis patients.

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.

The Role of Long Non-coding RNAs in Sepsis-Induced Cardiac Dysfunction

Sepsis is a syndrome with life-threatening organ dysfunction induced by a dysregulated host response to infection. The heart is one of the most commonly involved organs during sepsis, and cardiac dysfunction, which is usually indicative of an extremely poor clinical outcome, is a leading cause of death in septic cases. Despite substantial improvements in the understanding of the mechanisms that contribute to the origin and responses to sepsis, the prognosis of sepsis-induced cardiac dysfunction (SICD) remains poor and its molecular pathophysiological changes are not well-characterized. The recently discovered group of mediators known as long non-coding RNAs (lncRNAs) have presented novel insights and opportunities to explore the mechanisms and development of SICD and may provide new targets for diagnosis and therapeutic strategies. LncRNAs are RNA transcripts of more than 200 nucleotides with limited or no protein-coding potential. Evidence has rapidly accumulated from numerous studies on how lncRNAs function in associated regulatory circuits during SICD. This review outlines the direct evidence of the effect of lncRNAs on SICD based on clinical trials and animal studies. Furthermore, potential functional lncRNAs in SICD that have been identified in sepsis studies are summarized with a proven biological function in research on other cardiovascular diseases.

Long Non-coding RNA MEG3 Promotes Renal Tubular Epithelial Cell Pyroptosis by Regulating the miR-18a-3p/GSDMD Pathway in Lipopolysaccharide-Induced Acute Kidney Injury

Background and Objective: Acute kidney injury (AKI) is a complication of sepsis. Pyroptosis of gasdermin D (GSDMD)-mediated tubular epithelial cells (TECs) play important roles in pathogenesis of sepsis-associated AKI. Long non-coding RNA (lncRNA) maternally expressed gene 3 (MEG3), an imprinted gene involved in tumorigenesis, is implicated in pyroptosis occurring in multiple organs. Herein, we investigated the role and mechanisms of MEG3 in regulation of TEC pyroptosis in lipopolysaccharide (LPS)-induced AKI.

Materials and Methods: Male C57BL/6 mice and primary human TECs were treated with LPS for 24 h to establish the animal and cell models, respectively, of sepsis-induced AKI. Renal function was assessed by evaluation of serum creatinine and urea levels. Renal tubule injury score was assessed by Periodic acid-Schiff staining. Renal pyroptosis was assessed by evaluating expression of caspase-1, GSDMD, and inflammatory factors IL-1β and IL-18. Cellular pyroptosis was assessed by analyzing the release rate of LDH, expression of IL-1β, IL-18, caspase-1, and GSDMD, and using EtBr and EthD2 staining. MEG3 expression in renal tissues and cells was detected using RT-qPCR. The molecular mechanisms of MEG3 in LPS-induced AKI were assessed through bioinformatics analysis, RNA-binding protein immunoprecipitation, dual luciferase reporter gene assays, and a rescue experiment.

Results: Pyroptosis was detected in both LPS-induced animal and cell models, and the expression of MEG3 in these models was significantly up-regulated. MEG3-knockdown TECs treated with LPS showed a decreased number of pyroptotic cells, down-regulated secretion of LDH, IL-1β, and IL-18, and decreased expression of GSDMD, compared with those of controls; however, there was no difference in the expression of caspase-1 between MEG3 knockdown cells and controls. Bioinformatics analysis screened out miR-18a-3P, and further experiments demonstrated that MEG3 controls GSDMD expression by acting as a ceRNA for miR-18a-3P to promote TECs pyroptosis.

Conclusion: Our study demonstrates that lncRNA MEG3 promoted renal tubular epithelial pyroptosis by regulating the miR-18a-3p/GSDMD pathway in LPS-induced AKI.

Long non-coding RNA MEG3 as a candidate prognostic factor for induction therapy response and survival profile in childhood acute lymphoblastic leukemia patients

Childhood acute lymphoblastic leukemia (cALL) is a common hematological malignancy in children with unfavorable prognosis. Identifying novel prognostic factors is critical to optimize personalized treatment and improve their long-term outcomes. Thus, this study aimed to explore the correlation of longitudinal change of long non-coding RNA maternally expressed gene 3 (lnc-MEG3) with induction therapy response and survival profile in cALL patients. Totally 117 cALL patients and 50 pediatric patients (as controls) were recruited. Their lnc-MEG3 expressions from bone marrow mononuclear cells were detected by reverse transcription-quantitative polymerase chain reaction (before induction treatment and at day 15 after induction treatment). For their survival profile, the event-free survival (EFS) and overall survival (OS) were analyzed using follow-up data. Lnc-MEG3 expression was decreased in cALL patients (vs. controls) (p < .001). Meanwhile, higher baseline lnc-MEG3 expression was correlated with good prednisone response at day 8 (p = .001) and good bone marrow response at day 15 (p = .046) in cALL patients. However, no correlation of baseline lnc-MEG3 expression with immunophenotype (p = .088), or risk stratification (p = .155) in cALL patients was found. Notably, lnc-MEG3 expression was elevated during induction therapy (p < .001). Furthermore, lnc-MEG3 expression at day 15 was associated with good bone marrow response (p = .001) and its increment was also correlated with good bone marrow response (p = .022). More importantly, high lnc-MEG3 expression at baseline and day 15 were associated with prolonged EFS (both p < .05) and OS (both p < .05) in cALL patients. Lnc-MEG3 may serve as a prognostic factor for induction therapy response and survival profile in cALL patients.

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.

Long non-coding RNA CRNDE and toll-like receptor 3 correlate with disease severity, inflammation, and mortality in sepsis

Objective

This study aimed to assess the interaction between long non‐coding RNA colorectal neoplasia differentially expressed (lncRNA CRNDE) and toll‐like receptor 3 (TLR3), and assess their correlations with disease severity, inflammation, and 28‐days mortality in sepsis patients.

Methods

We consecutively enrolled 146 sepsis patients and 146 healthy controls (HCs), and collected their peripheral blood mononuclear cells to detect lncRNA CRNDE and TLR3 expressions using reverse transcription quantitative polymerase chain reaction. LncRNA CRNDE and TLR3 in sepsis patients were classified into four clusters according to quantile expressions (Quantile 1 (0%‐24%), Quantile 2 (25%‐50%), Quantile 3 (50%‐74%), and Quantile 4 (75%‐100%)) for correlation analysis.

Results

LncRNA CRNDE was upregulated in sepsis patients compared with HCs, and it showed good value in differentiating sepsis patients form HCs by receiver operating characteristic curve analysis. In sepsis patients, lncRNA CRNDE positively correlated with acute pathologic and chronic health evaluation II (APACHE II) score and sequential organ failure assessment (SOFA) score, as well as serum creatinine (Scr). As for inflammation, lncRNA CRNDE positively correlated with C‐reactive protein (CRP), tumor necrosis factor‐α (TNF‐α), interleukin (IL)‐1β, IL‐6, and IL‐8. Regarding mortality, lncRNA CRNDE positively correlated with 28‐days mortality. Furthermore, lncRNA CRNDE positively correlated with TLR3, and TLR3 positively associated with APACHE II score, SOFA score, Scr, albumin, CRP, TNF‐α, IL‐1β, IL‐6, IL‐8, and 28‐days mortality in sepsis patients.

Conclusion

LncRNA CRNDE interacts with TLR3, both of which correlate with advanced disease severity, inflammation, and higher 28‐days mortality in sepsis patients.

An Update on Sepsis Biomarkers

Sepsis is a dysregulated systemic reaction to a common infection, that can cause life-threatening organ dysfunction. Over the last decade, the mortality rate of patients with sepsis has decreased as long as patients are treated according to the recommendations of the Surviving Sepsis Campaign, but is still unacceptably high. Patients at risk of sepsis should therefore be identified prior to the onset of organ dysfunction and this requires a rapid diagnosis and a prompt initiation of treatment. Unfortunately, there is no gold standard for the diagnosis of sepsis and traditional standard culture methods are time-consuming. Recently, in order to overcome these limitations, biomarkers which could help in predicting the diagnosis and prognosis of sepsis, as well as being useful for monitoring the response to treatments, have been identified. In addition, recent advances have led to the development of newly identified classes of biomarkers such as microRNAs, long-non-coding RNAs, and the human microbiome. This review focuses on the latest information on biomarkers that can be used to predict the diagnosis and prognosis of sepsis.

Lnc-MEG3 acts as a potential biomarker for predicting increased disease risk, systemic inflammation, disease severity, and poor prognosis of sepsis via interacting with miR-21

BACKGROUND

This study aimed to investigate the correlations of long non-coding RNA maternally expressed gene 3 (lnc-MEG3), microRNA (miR)-21, and lnc-MEG3/miR-21 axis with disease risk, inflammation, disease severity, and 28-day mortality of sepsis.

METHODS

Totally, 219 sepsis patients and 219 health controls (HCs) were enrolled. Plasma samples were obtained from sepsis patients within 24 hours after admission and from HCs on enrollment to detect lnc-MEG3 and miR-21 expressions by real-time quantitative polymerase chain reaction.

RESULTS

The lnc-MEG3 expression and lnc-MEG3/miR-21 axis were increased, while miR-21 expression was decreased in sepsis patients compared with HCs. Lnc-MEG3 (area under the curve (AUC): 0.887, 95% confidence interval (CI): 0.856-0.917) and lnc-MEG3/miR-21 axis (AUC: 0.934, 95% CI: 0.909-0.958) had good values for predicting elevated sepsis risk, while miR-21 (AUC: 0.801, 95% CI: 0.758-0.844) presented a good predictive value for reduced sepsis risk. Furthermore, lnc-MEG3 expression and lnc-MEG3/miR-21 axis positively correlated with, whereas miR-21 expression negatively correlated with acute pathologic and chronic health evaluation II, sequential organ failure assessment score, serum creatinine, C-reactive protein, tumor necrosis factor-α, interleukin (IL)-1β, IL-6, and IL-17 in sepsis patients. Additionally, lnc-MEG3 (AUC: 0.704, 95% CI: 0.626-0.783) and lnc-MEG3/miR-21 axis (AUC: 0.669, 95% CI: 0.589-0.750) exhibited acceptable values in predicting higher 28-day mortality risk, while miR-21 (AUC: 0.588, 95% CI: 0.505-0.672) presented a poor predictive value for lower 28-day mortality risk in sepsis patients.

CONCLUSION

Lnc-MEG3 might serve as a potential biomarker for the development, progression, and prognosis prediction of sepsis via interacting with miR-21.