MicroRNAs 143 and 150 in whole blood enable detection of T-cell immunoparalysis in sepsis

MicroRNAs in Sepsis

Sepsis is an insidious and frequent condition of severe inflammation due to infections. Several biomarkers have been established for initial screening, but the non-specific nature of the existing biomarkers has led to the investigation of more sensitive and specific tools, such as microRNAs (miRs). These non-coding RNAs are involved in several diseases, including sepsis, due to their roles in cellular homeostasis. Herein, a literature overview was attempted to distinguish the most prominent miRs identified in septic conditions and their usefulness in diagnosis, prognosis and even classification of sepsis. miRs implicated in the regulation of pro and anti-inflammatory mechanisms, such as MIR-146a, MIR-155, MIR-181b, MIR-223-5p, MIR-494-3p, MIR-2055b, MIR-150 and MIR-143 have been pinpointed as acceptable testing tools. Furthermore, the use of miRs as screening panels, specific for septic parameters, such as type of causal infection, inflammation immune pathways affected (NF-kB, STAT/JACK), organs inflicted, as well as parallel screening of certain miRs alongside other long non-coding RNAs (LNCs), as co-regulators of sepsis progression. Overall, miRs exhibit benefits in terms of specificity and sensitivity, as well as practical ease of use and test stability. Furthermore, miRs could offer valuable insights into the molecular basis of disease causality and provide valuable therapeutic information.

MiR-150 levels are related to in-hospital mortality in non-HIV Pneumocystis pneumonia patients

Pneumocystis pneumonia (PCP) is a common opportunistic infection that occurs in immunocompromised patients. Compared with HIV patients, PCP in non-HIV patients tends to follow up a more urgent course and poorer prognosis. Therefore, markers that could predict survival of PCP patients in non-HIV population are of great value. MiRNA-150 has been widely studied in many diseases since it has been identified as a vital regulator of immune cell differentiation and activation. We thus conduct this study aiming to evaluate the prognostic value of miR-150 level in non-HIV PCP. First, the expression levels of miR-150 were compared between PCP patients and healthy volunteers. The miR-150 levels in immune cells were also detected in PCP mouse models. Then the prognostic value of miR-150 was further assessed in another PCP population (n = 72). The expression levels of miR-150 were measured by reverse transcription real-time PCR (RT-PCR) technique. Our data demonstrated significantly decreased miR-150 expression levels in PCP patients and mouse models compared to controls. The miR-150 levels also decreased in various immune cells of PCP mouse models. With a cut-off value of 3.48, the area under the curve, sensitivity, specificity of miR-150 to predicate PCP mortality were 0.845, 68.2% and 96.0%, respectively. In conclusion, miR-150 expression value might serve as a potential biomarker to identify PCP patients at high risk of death.

Harnessing Extracellular microRNAs for Diagnostics and Therapeutics in Acute Systemic Inflammation

Micro-ribonucleic acids (miRNAs) are small sequences of genetic materials that are primarily transcribed from the intronic regions of deoxyribonucleic acid (DNAs), and they are pivotal in regulating messenger RNA (mRNA) expression. miRNAs were first discovered to regulate mRNAs of the same cell in which they were transcribed. Recent studies have unveiled their ability to traverse cells, either encapsulated in vesicles or freely bound to proteins, influencing distant recipient cells. Activities of extracellular miRNAs have been observed during acute inflammation in clinically relevant pathologies, such as sepsis, shock, trauma, and ischemia/reperfusion (I/R) injuries. This review comprehensively explores the activity of miRNAs during acute inflammation as well as the mechanisms of their extracellular transport and activity. Evaluating the potential of extracellular miRNAs as diagnostic biomarkers and therapeutic targets in acute inflammation represents a critical aspect of this review. Finally, this review concludes with novel concepts of miRNA activity in the context of alleviating inflammation, delivering potential future directions to advance the field of miRNA therapeutics.

Macrophage-derived exosomal miRNA-141 triggers endothelial cell pyroptosis by targeting NLRP3 to accelerate sepsis progression

Sepsis, critical condition marked by severe organ dysfunction from uncontrolled infection, involves the endothelium significantly. Macrophages, through paracrine actions, play a vital role in sepsis, but their mechanisms in sepsis pathogenesis remain elusive. Objective: We aimed to explore how macrophage-derived exosomes with low miR-141 expression promote pyroptosis in endothelial cells (ECs). Exosomes from THP-1 cell supernatant were isolated and characterized. The effects of miR-141 mimic/inhibitor on apoptosis, proliferation, and invasion of Human Umbilical Vein Endothelial Cells (HUVECs) were assessed using flow cytometry, CCK-8, and transwell assays. Key pyroptosis-related proteins, including caspase-1, IL-18, IL-1β, NLR Family Pyrin Domain Containing 3 (NLRP3), ASC, and cleaved-GSDMD, were analyzed via Western blot. The interaction between miR-141 and NLRP3 was studied using RNAhybrid v2.2 and dual-Luciferase reporter assays. The mRNA and protein level of NLRP3 after exosomal miR-141 inhibitor treatment was detected by qPCR and Western blot, respectively. Exosomes were successfully isolated. miR-141 mimic reduced cell death and pyroptosis-related protein expression in HUVECs, while the inhibitor had opposite effects, increasing cell death, and enhancing pyroptosis protein expression. Additionally, macrophage-derived exosomal miR-141 inhibitor increased cell death and pyroptosis-related proteins in HUVECs. miR-141 inhibits NLRP3 transcription. Macrophages facilitate sepsis progression by secreting miR-141 decreased exosomes to activate NLRP3-mediated pyroptosis in ECs, which could be a potentially valuable target of sepsis therapy.

Persistent sepsis-induced transcriptomic signatures in signaling pathways of peripheral blood leukocytes: A pilot study

Sepsis is a dysregulated immune response to infections that frequently precipitates multiple organ dysfunction and death despite intensive supportive therapy. The aim of the present study was to identify sepsis-induced alterations in the signaling transcriptome of peripheral blood leukocytes that might shed light on the elusive transition from proinflammatory to anti-inflammatory responses and underlie long-term post-sepsis immunosuppression. Peripheral blood leukocytes were collected from subjects (i) with systemic inflammation, (ii) with sepsis in the acute phase and (iii) 6 months after recovery from sepsis, corresponding to progressive stages of the disease. Transcriptomic analysis was performed with the QuantStudio 12K Flex OpenArray Human Signal Transduction Panel analyzing transcripts of 573 genes playing a significant role in signaling. Of them, 145 genes exhibited differential expression in sepsis as compared to systemic inflammation. Pathway analysis revealed enhanced expression levels of genes involved in primary immune responses (proinflammatory cytokines, neutrophil and macrophage activation markers) and signatures characteristic of immunosuppression (increased expression of anti-inflammatory cytokines and proapoptotic genes; diminished expression of T and B cell receptor dependent activating and survival pathways). Importantly, sepsis-induced expression patterns of 39 genes were not normalized by the end of the 6-month follow-up period, indicating expression aberrations persisting long after clinical recovery. Functional analysis of these transcripts revealed downregulation of the antiapoptotic Wnt and mTOR signaling pathways that might explain the post-sepsis immunosuppression commonly seen in sepsis survivors.

The emerging role of miRNA-122 in infectious diseases: Mechanisms and potential biomarkers

microRNAs (miRNAs) are small, non-coding RNA molecules that play crucial regulatory roles in numerous cellular processes. Recent investigations have highlighted the significant involvement of miRNA-122 (miR-122) in the pathogenesis of infectious diseases caused by diverse pathogens, encompassing viral, bacterial, and parasitic infections. In the context of viral infections, miR-122 exerts regulatory control over viral replication by binding to the viral genome and modulating the host's antiviral response. For instance, in hepatitis B virus (HBV) infection, miR-122 restricts viral replication, while HBV, in turn, suppresses miR-122 expression. Conversely, miR-122 interacts with the hepatitis C virus (HCV) genome, facilitating viral replication. Regarding bacterial infections, miR-122 has been found to regulate host immune responses by influencing inflammatory cytokine production and phagocytosis. In Vibrio anguillarum infections, there is a significant reduction in miR-122 expression, contributing to the pathophysiology of bacterial infections. Toll-like receptor 14 (TLR14) has been identified as a novel target gene of miR-122, affecting inflammatory and immune responses. In the context of parasitic infections, miR-122 plays a crucial role in regulating host lipid metabolism and immune responses. For example, during Leishmania infection, miR-122-containing extracellular vesicles from liver cells are unable to enter infected macrophages, leading to a suppression of the inflammatory response. Furthermore, miR-122 exhibits promise as a potential biomarker for various infectious diseases. Its expression level in body fluids, particularly in serum and plasma, correlates with disease severity and treatment response in patients affected by HCV, HBV, and tuberculosis. This paper also discusses the potential of miR-122 as a biomarker in infectious diseases. In summary, this review provides a comprehensive and insightful overview of the emerging role of miR-122 in infectious diseases, detailing its mechanism of action and potential implications for the development of novel therapeutic strategies.

Identification of an Immune-Related Gene Diagnostic Model and Potential Drugs in Sepsis Using Bioinformatics and Pharmacogenomics Approaches

Purpose

Sepsis is an organ dysfunction with high mortality. Early identification, diagnosis, and effective treatment of sepsis are beneficial to the survival of patients. This study aimed to find potential diagnosis and immune-related genes, and drug targets, which could provide novel diagnostic and therapeutic markers for sepsis.

Patients and Methods

The GSE69063, GSE154918 and GSE28750 datasets were integrated to evaluate immune infiltration and identify differentially expressed genes (DEGs) and immune-related genes. Weighted gene co-expression network analysis (WGCNA) was applied to find the hub module related to immune score and sepsis. Immune-related key genes were screened out by taking interaction of DEGs, immune-related genes, and genes in hub module. Protein-protein interaction (PPI) analysis was used to further screen immune-related hub genes, followed by construction of a diagnostic model based on immune-related hub genes. Functional analysis and drug prediction of immune-related hub genes were, respectively, performed by David software and DGIdb database, followed by expression validation by reverse transcriptase polymerase chain reaction (RT-PCR).

Results

Totally, 93 immune-related key genes were identified between 561 DEGs, 1793 immune-related genes and 12,459 genes in the hub module of WGCNA. Through PPI analysis, a total of 5 diagnose and immune-related hub genes were further obtained, including IL7R, IL10, CD40LG, CD28 and LCN2. Relationship pairs between these 5 genes and immune cell were identified, including LCN2/IL7R/CD28-activated dendritic cell and IL10-immature B cell. Based on pharmacogenomics, 17 candidate drugs might interact with IL 10, including CYCLOSPORINE. Six candidate drugs might interact with CD28 and 11 with CD40LG, CD40LG and CD28 were drug targets of ALDESLEUKIN. Four significantly enriched signaling pathways were identified, such as T cell receptor signaling pathway, NF-kappa B signaling pathway and JAK-STAT signaling pathway.

Conclusion

The 5-gene diagnostic model could be used to diagnose and guide clinical immunotherapy for sepsis.

Urinary microRNAs in sepsis function as a novel prognostic marker

Renal dysfunction is a common complication of sepsis. Early diagnosis and prompt treatment of sepsis with renal insufficiency are crucial for improving patient outcomes. Diagnostic markers can help identify patients at risk for sepsis and AKI, allowing for early intervention and potentially preventing the development of severe complications. The aim of the present study was to investigate the expression difference of urinary microRNAs (miRNAs/miRs) in elderly patients with sepsis and secondary renal insufficiency, and to evaluate their diagnostic value in these patients. In the present study, RNA was extracted from urine samples of elderly sepsis-related acute renal damage patients and the expression profiles of several miRNAs were analyzed. In order to evaluate the expression profile of several miRNAs, urine samples from elderly patients with acute renal damage brought on by sepsis were obtained. RNA extraction and sequencing were then performed on the samples. Furthermore, multiple bioinformatics methods were used to analyze miRNA profiles, including differential expression analysis, and Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis of different miRNA target genes, to further explore miRNAs that are suitable for utilization as biomarkers. A total of four miRNAs, including hsa-miR-31-5p, hsa-miR-151a-3p, hsa-miR-142-5p and hsa-miR-16-5p, were identified as potential biological markers and were further confirmed in sepsis using reverse transcription-quantitative PCR. The results of the present study demonstrated that the four urinary miRNAs were differentially expressed and may serve as specific markers for prediction of secondary acute kidney injury in elderly patients with sepsis.

Notch Signaling in Acute Inflammation and Sepsis

Notch signaling, a highly conserved pathway in mammals, is crucial for differentiation and homeostasis of immune cells. Besides, this pathway is also directly involved in the transmission of immune signals. Notch signaling per se does not have a clear pro- or anti-inflammatory effect, but rather its impact is highly dependent on the immune cell type and the cellular environment, modulating several inflammatory conditions including sepsis, and therefore significantly impacts the course of disease. In this review, we will discuss the contribution of Notch signaling on the clinical picture of systemic inflammatory diseases, especially sepsis. Specifically, we will review its role during immune cell development and its contribution to the modulation of organ-specific immune responses. Finally, we will evaluate to what extent manipulation of the Notch signaling pathway could be a future therapeutic strategy.

Knockdown of long noncoding RNA MIAT attenuates hypoxia-induced cardiomyocyte injury by regulating the miR-488-3p/Wnt/β-catenin pathway

Dysfunction of cardiomyocytes contributes to the development of acute myocardial infarction (AMI). Nonetheless, the regulatory mechanism of lncRNA myocardial infarction-associated transcript (MIAT) in cardiomyocyte injury remains largely unclear. The cardiomyocyte injury was assessed via cell viability and apoptosis using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) and flow cytometry, respectively. The levels of MIAT, microRNA (miR)-488-3p, and Wnt5a were detected via quantitative real-time polymerase chain reaction and Western blot. After bioinformatical analysis, the binding between miR-488-3p and MIAT or Wnt5a was confirmed via dual-luciferase reporter, RNA immunoprecipitation, and RNA pull-down assays. Our results showed that MIAT expression was increased in AC16 cells after hypoxia treatment. Silencing of MIAT alleviated hypoxia-induced viability reduction, apoptosis increase, and Wnt/β-catenin pathway activation. MIAT directly targeted miR-488-3p. MiR-488-3p might repress hypoxia-induced cardiomyocyte injury, and its knockdown reversed the effect of MIAT depletion on cardiomyocyte injury. Wnt5a was validated as a target of miR-488-3p. Wnt5a expression restoration attenuated the influence of MIAT knockdown on hypoxia-triggered cardiomyocyte injury. Our findings demonstrated that downregulation of MIAT might mitigate hypoxia-induced cardiomyocyte injury partly through miR-488-3p mediated Wnt/β-catenin pathway.

miR-146a, miR-221, and miR-155 are Involved in Inflammatory Immune Response in Severe COVID-19 Patients

COVID-19 infection triggered a global public health crisis during the 2020-2022 period, and it is still evolving. This highly transmissible respiratory disease can cause mild symptoms up to severe pneumonia with potentially fatal respiratory failure. In this cross-sectional study, 41 PCR-positive patients for SARS-CoV-2 and 42 healthy controls were recruited during the first wave of the pandemic in Mexico. The plasmatic expression of five circulating miRNAs involved in inflammatory and pathological host immune responses was assessed using RT-qPCR (Reverse Transcription quantitative Polymerase Chain Reaction). Compared with controls, a significant upregulation of miR-146a, miR-155, and miR-221 was observed; miR-146a had a positive correlation with absolute neutrophil count and levels of brain natriuretic propeptide (proBNP), and miR-221 had a positive correlation with ferritin and a negative correlation with total cholesterol. We found here that CDKN1B gen is a shared target of miR-146a, miR-221-3p, and miR-155-5p, paving the way for therapeutic interventions in severe COVID-19 patients. The ROC curve built with adjusted variables (miR-146a, miR-221-3p, miR-155-5p, age, and male sex) to differentiate individuals with severe COVID-19 showed an AUC of 0.95. The dysregulation of circulating miRNAs provides new insights into the underlying immunological mechanisms, and their possible use as biomarkers to discriminate against patients with severe COVID-19. Functional analysis showed that most enriched pathways were significantly associated with processes related to cell proliferation and immune responses (innate and adaptive). Twelve of the predicted gene targets have been validated in plasma/serum, reflecting their potential use as predictive prognosis biomarkers.

Role of miRNA dysregulation in sepsis

Background

Sepsis is defined as a state of multisystem organ dysfunction secondary to a dysregulated host response to infection and causes millions of deaths worldwide annually. Novel ways to counteract this disease are needed and such tools may be heralded by a detailed understanding of its molecular pathogenesis. MiRNAs are small RNA molecules that target mRNAs to inhibit or degrade their translation and have important roles in several disease processes including sepsis.

Main body

The current review adopted a strategic approach to analyzing the widespread literature on the topic of miRNAs and sepsis. A pubmed search of “miRNA or microRNA or small RNA and sepsis not review” up to and including January 2021 led to 1140 manuscripts which were reviewed. Two hundred and thirty-three relevant papers were scrutinized for their content and important themes on the topic were identified and subsequently discussed, including an in-depth look at deregulated miRNAs in sepsis in peripheral blood, myeloid derived suppressor cells and extracellular vesicles.

Conclusion

Our analysis yielded important observations. Certain miRNAs, namely miR-150 and miR-146a, have consistent directional changes in peripheral blood of septic patients across numerous studies with strong data supporting a role in sepsis pathogenesis. Furthermore, a large body of literature show miRNA signatures of clinical relevance, and lastly, many miRNAs deregulated in sepsis are associated with the process of endothelial dysfunction. This review offers a widespread, up-to-date and detailed discussion of the role of miRNAs in sepsis and is meant to stimulate further work in the field due to the potential of these small miRNAs in prompt diagnostics, prognostication and therapeutic agency.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-022-00527-z.

Non-coding RNAs: Key players in T cell exhaustion

T cell exhaustion caused by continuous antigen stimulation in chronic viral infections and the tumor microenvironment is a major barrier to successful elimination of viruses and tumor cells. Although immune checkpoint inhibitors should reverse T cell exhaustion, shortcomings, such as off-target effects and single targets, limit their application. Therefore, it is important to identify molecular targets in effector T cells that simultaneously regulate the expression of multiple immune checkpoints. Over the past few years, non-coding RNAs, including microRNAs and long non-coding RNAs, have been shown to participate in the immune response against viral infections and tumors. In this review, we focus on the roles and underlying mechanisms of microRNAs and long non-coding RNAs in the regulation of T cell exhaustion during chronic viral infections and tumorigenesis. We hope that this review will stimulate research to provide more precise and effective immunotherapies against viral infections and tumors.

Screening of Sepsis Biomarkers Based on Bioinformatics Data Analysis

Methods

Gene expression profiles of GSE13904, GSE26378, GSE26440, GSE65682, and GSE69528 were obtained from the National Center for Biotechnology Information (NCBI). The differentially expressed genes (DEGs) were searched using limma software package. Gene Ontology (GO) functional analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, and protein-protein interaction (PPI) network analysis were performed to elucidate molecular mechanisms of DEGs and screen hub genes.

Results

A total of 108 DEGs were identified in the study, of which 67 were upregulated and 41 were downregulated. 15 superlative diagnostic biomarkers (CCL5, CCR7, CD2, CD27, CD274, CD3D, GNLY, GZMA, GZMH, GZMK, IL2RB, IL7R, ITK, KLRB1, and PRF1) for sepsis were identified by bioinformatics analysis.

Conclusion

15 hub genes (CCL5, CCR7, CD2, CD27, CD274, CD3D, GNLY, GZMA, GZMH, GZMK, IL2RB, IL7R, ITK, KLRB1, and PRF1) have been elucidated in this study, and these biomarkers may be helpful in the diagnosis and therapy of patients with sepsis.

ICOS-Fc as innovative immunomodulatory approach to counteract inflammation and organ injury in sepsis

Inducible T cell co-stimulator (ICOS), an immune checkpoint protein expressed on activated T cells and its unique ligand, ICOSL, which is expressed on antigen-presenting cells and non-hematopoietic cells, have been extensively investigated in the immune response. Recent findings showed that a soluble recombinant form of ICOS (ICOS-Fc) can act as an innovative immunomodulatory drug as both antagonist of ICOS and agonist of ICOSL, modulating cytokine release and cell migration to inflamed tissues. Although the ICOS-ICOSL pathway has been poorly investigated in the septic context, a few studies have reported that septic patients have reduced ICOS expression in whole blood and increased serum levels of osteopontin (OPN), that is another ligand of ICOSL. Thus, we investigated the pathological role of the ICOS-ICOSL axis in the context of sepsis and the potential protective effects of its immunomodulation by administering ICOS-Fc in a murine model of sepsis. Polymicrobial sepsis was induced by cecal ligation and puncture (CLP) in five-month-old male wild-type (WT) C57BL/6, ICOS-/-, ICOSL-/- and OPN-/- mice. One hour after the surgical procedure, either CLP or Sham (control) mice were randomly assigned to receive once ICOS-Fc, F119SICOS-Fc, a mutated form uncapable to bind ICOSL, or vehicle intravenously. Organs and plasma were collected 24 h after surgery for analyses. When compared to Sham mice, WT mice that underwent CLP developed within 24 h a higher clinical severity score, a reduced body temperature, an increase in plasma cytokines (TNF-α, IL-1β, IL-6, IFN-γ and IL-10), liver injury (AST and ALT) and kidney (creatinine and urea) dysfunction. Administration of ICOS-Fc to WT CLP mice reduced all of these abnormalities caused by sepsis. Similar beneficial effects were not seen in CLP-mice treated with F119SICOS-Fc. Treatment of CLP-mice with ICOS-Fc also attenuated the sepsis-induced local activation of FAK, P38 MAPK and NLRP3 inflammasome. ICOS-Fc seemed to act at both sides of the ICOS-ICOSL interaction, as the protective effect was lost in septic knockout mice for the ICOS or ICOSL genes, whereas it was maintained in OPN knockout mice. Collectively, our data show the beneficial effects of pharmacological modulation of the ICOS-ICOSL pathway in counteracting the sepsis-induced inflammation and organ dysfunction.

Modes of action and diagnostic value of miRNAs in sepsis

Sepsis is a clinical syndrome defined as a dysregulated host response to infection resulting in life-threatening organ dysfunction. Sepsis is a major public health concern associated with one in five deaths worldwide. Sepsis is characterized by unbalanced inflammation and profound and sustained immunosuppression, increasing patient susceptibility to secondary infections and mortality. microRNAs (miRNAs) play a central role in the control of many biological processes, and deregulation of their expression has been linked to the development of oncological, cardiovascular, neurodegenerative and metabolic diseases. In this review, we discuss the role of miRNAs in sepsis pathophysiology. Overall, miRNAs are seen as promising biomarkers, and it has been proposed to develop miRNA-based therapies for sepsis. Yet, the picture is not so straightforward because of the versatile and dynamic features of miRNAs. Clearly, more research is needed to clarify the expression and role of miRNAs in sepsis, and to promote the use of miRNAs for sepsis management.

Ketone Bodies Improve Human CD8+ Cytotoxic T-Cell Immune Response During COVID-19 Infection

Severe COVID-19 is characterized by profound CD8+ T-cell dysfunction, which cannot be specifically treated to date. We here investigate whether metabolic CD8+ T-cell reprogramming by ketone bodies could be a promising strategy to overcome the immunoparalysis in COVID-19 patients. This approach was triggered by our recent pioneering study, which has provided evidence that CD8+ T-cell capacity in healthy subjects could be significantly empowered by a Ketogenic Diet. These improvements were achieved by immunometabolic rewiring toward oxidative phosphorylation. We here report similar strengthening of CD8+ T cells obtained from severely diseased COVID-19 patients: Flow cytometry and ELISA revealed elevated cytokine expression and secretion (up to + 24%) upon ketone treatment and enhanced cell lysis capacity (+ 21%). Metabolic analyses using Seahorse technology revealed upregulated mitochondrial respiratory chain activity (+ 25%), enabling both superior energy supply (+ 44%) and higher mitochondrial reactive oxygen species signaling. These beneficial effects of ketones might represent evolutionary conserved mechanisms to strengthen human immunity. Our findings pave the road for metabolic treatment studies in COVID-19.

MicroRNA-122-5p regulates coagulation and inflammation through MASP1 and HO-1 genes

MiR-122-5p is a diagnostic and prognostic biomarker of sepsis and is correlated with coagulation abnormalities in sepsis. However, its functional aspects remain unknown. This study applied bioinformatics analysis to evaluate the coagulation-related target genes for miR-122-5p. THP-1, HUVEC, and LO-2 cell lines were used in this study. MiR-122-5p mimics were transfected into the three previously mentioned cell lines, which helped in detecting mRNA and protein levels by qRT-PCR and western blotting, respectively. Serum samples from 84 sepsis patients were collected to evaluate target gene code proteins. The protein and mRNA levels of Heme oxygenase1(HO-1), IL-1β, IL-6, monocyte chemoattractant protein 1(MCP-1), and TNF-α were also evaluated in three cell lines. Mannan binding lectin serine peptidase 1(MASP1) was a direct target gene of miR-122-5p, and levels of MASP1, C3, and C4 were all significantly lower in the sepsis with disseminated intravascular coagulopathy (DIC) group than in the sepsis without DIC group. MiR-122-5p mimics could down-regulate HO-1 in the three cell lines. HO-1, IL-1β, IL-6, MCP-1, and TNF-α gene and protein levels were decreased after miR-122-5p mimics were added. MiR-122-5p regulated coagulation and inflammation through MASP1 and HO-1, respectively.

Thrombosis-related circulating miR-16-5p is associated with disease severity in patients hospitalised for COVID-19

SARS-CoV-2 tropism for the ACE2 receptor, along with the multifaceted inflammatory reaction, is likely to drive the generalized hypercoagulable and thrombotic state seen in patients with COVID-19. Using the original bioinformatic workflow and network medicine approaches we reanalysed four coronavirus-related expression datasets and performed co-expression analysis focused on thrombosis and ACE2 related genes. We identified microRNAs (miRNAs) which play role in ACE2-related thrombosis in coronavirus infection and further, we validated the expressions of precisely selected miRNAs-related to thrombosis (miR-16-5p, miR-27a-3p, let-7b-5p and miR-155-5p) in 79 hospitalized COVID-19 patients and 32 healthy volunteers by qRT-PCR. Consequently, we aimed to unravel whether bioinformatic prioritization could guide selection of miRNAs with a potential of diagnostic and prognostic biomarkers associated with disease severity in patients hospitalized for COVID-19. In bioinformatic analysis, we identified EGFR, HSP90AA1, APP, TP53, PTEN, UBC, FN1, ELAVL1 and CALM1 as regulatory genes which could play a pivotal role in COVID-19 related thrombosis. We also found miR-16-5p, miR-27a-3p, let-7b-5p and miR-155-5p as regulators in the coagulation and thrombosis process. In silico predictions were further confirmed in patients hospitalized for COVID-19. The expression levels of miR-16-5p and let-7b in COVID-19 patients were lower at baseline, 7-days and 21-day after admission compared to the healthy controls (p < 0.0001 for all time points for both miRNAs). The expression levels of miR-27a-3p and miR-155-5p in COVID-19 patients were higher at day 21 compared to the healthy controls (p = 0.007 and p < 0.001, respectively). A low baseline miR-16-5p expression presents predictive utility in assessment of the hospital length of stay or death in follow-up as a composite endpoint (AUC:0.810, 95% CI, 0.71-0.91, p < 0.0001) and low baseline expression of miR-16-5p and diabetes mellitus are independent predictors of increased length of stay or death according to a multivariate analysis (OR: 9.417; 95% CI, 2.647-33.506; p = 0.0005 and OR: 6.257; 95% CI, 1.049-37.316; p = 0.044, respectively). This study enabled us to better characterize changes in gene expression and signalling pathways related to hypercoagulable and thrombotic conditions in COVID-19. In this study we identified and validated miRNAs which could serve as novel, thrombosis-related predictive biomarkers of the COVID-19 complications, and can be used for early stratification of patients and prediction of severity of infection development in an individual.Abbreviations: ACE2, angiotensin-converting enzyme 2AF, atrial fibrillationAPP, Amyloid Beta Precursor ProteinaPTT, activated partial thromboplastin timeAUC, Area under the curveAβ, amyloid betaBMI, body mass indexCAD, coronary artery diseaseCALM1, Calmodulin 1 geneCaM, calmodulinCCND1, Cyclin D1CI, confidence intervalCOPD, chronic obstructive pulmonary diseaseCOVID-19, Coronavirus disease 2019CRP, C-reactive proteinCV, CardiovascularCVDs, cardiovascular diseasesDE, differentially expressedDM, diabetes mellitusEGFR, Epithelial growth factor receptorELAVL1, ELAV Like RNA Binding Protein 1FLNA, Filamin AFN1, Fibronectin 1GEO, Gene Expression OmnibushiPSC-CMs, Human induced pluripotent stem cell-derived cardiomyocytesHSP90AA1, Heat Shock Protein 90 Alpha Family Class A Member 1Hsp90α, heat shock protein 90αICU, intensive care unitIL, interleukinIQR, interquartile rangelncRNAs, long non-coding RNAsMI, myocardial infarctionMiRNA, MiR, microRNAmRNA, messenger RNAncRNA, non-coding RNANERI, network-medicine based integrative approachNF-kB, nuclear factor kappa-light-chain-enhancer of activated B cellsNPV, negative predictive valueNXF, nuclear export factorPBMCs, Peripheral blood mononuclear cellsPCT, procalcitoninPPI, Protein-protein interactionsPPV, positive predictive valuePTEN, phosphatase and tensin homologqPCR, quantitative polymerase chain reactionROC, receiver operating characteristicSARS-CoV-2, severe acute respiratory syndrome coronavirus 2SD, standard deviationTLR4, Toll-like receptor 4TM, thrombomodulinTP53, Tumour protein P53UBC, Ubiquitin CWBC, white blood cells.

lncRNA NEAT1 aggravates sepsis-induced lung injury by regulating the miR-27a/PTEN axis

Sepsis is an acute inflammatory reaction and a cause of acute respiratory distress syndrome (ARDS). In the present study, we explored the roles and underlying mechanism of the lncRNA Nuclear enriched abundant transcript 1 (NEAT1) in ARDS. The expression levels of genes, proteins and pro-inflammatory cytokines in patients with ARDS, LPS-stimulated cells and septic mouse models were quantified using qPCR, western blotting and ELISA assays, respectively. The molecular targeting relationship was validated by conducting a dual-luciferase reporter assay. Cell proliferation was assessed using the Cell Counting Kit-8 (CCK-8) assay. The cell cycle phase was determined by flow cytometry assay. The expression levels of NEAT1 and pro-inflammatory cytokines were higher in patients with ARDS and septic models than in controls. Knockdown of NEAT1 significantly increased cell proliferation and cycle progression and prolonged mouse survival in vitro and in vivo. Mechanistically, miR-27a was identified as a downstream target of NEAT1 and directly inhibited PTEN expression. Further rescue experiments revealed that inhibition of miR-27a impeded the promoting effects of NEAT1 silence on cell proliferation and cycle progression, whereas inhibition of PTEN markedly weakened the inhibitory effects of NEAT1 overexpression on cell proliferation and cycle progression. Altogether, our study revealed that NEAT1 plays a promoting role in the progression of ARDS via the NEAT1/miR-27a/PTEN regulatory network, providing new insight into the pathologic mechanism behind ARDS.

Very-low-carbohydrate diet enhances human T-cell immunity through immunometabolic reprogramming

Very-low-carbohydrate diet triggers the endogenous production of ketone bodies as alternative energy substrates. There are as yet unproven assumptions that ketone bodies positively affect human immunity. We have investigated this topic in an in vitro model using primary human T cells and in an immuno-nutritional intervention study enrolling healthy volunteers. We show that ketone bodies profoundly impact human T-cell responses. CD4+ , CD8+ , and regulatory T-cell capacity were markedly enhanced, and T memory cell formation was augmented. RNAseq and functional metabolic analyses revealed a fundamental immunometabolic reprogramming in response to ketones favoring mitochondrial oxidative metabolism. This confers superior respiratory reserve, cellular energy supply, and reactive oxygen species signaling. Our data suggest a very-low-carbohydrate diet as a clinical tool to improve human T-cell immunity. Rethinking the value of nutrition and dietary interventions in modern medicine is required.

MicroRNA Expression Changes in Kidney Transplant: Diagnostic Efficacy of miR-150-5p as Potential Rejection Biomarker, Pilot Study

Background: The kidney allograft biopsy is considered the gold standard for rejection diagnosis but is invasive and could be indeterminate. Several publications point to the role of miRNA expression in suggesting its involvement in the acceptance or rejection of organ transplantation. This study aimed to analyze microRNAs involved in the differentiation and activation of B and T lymphocytes from kidney transplant (KT) patients’ peripheral blood leukocytes to be used as biomarkers of acute renal rejection (AR). Methods: A total of 15 KT patients with and without acute rejection (AR/NAR) were analyzed and quantified by miRNA PCR array. A total of 84 miRNAs related to lymphocyte differentiation and activation B and T were studied. The functions and biological pathways were analyzed to predict the potential targets of differential expressed miRNAs. Results: Six miRNA were increased in the AR group (miR-191-5p, miR-223-3p, miR-346, miR-423-5p, miR-574-3p, and miR-181d) and miR-150-5p was increased in the NAR group. In silico studies showed a total of 2603 target genes for the increased miRNAs in AR, while for the decrease miRNA, a total of 1107 target-potential genes were found. Conclusions: Our results show that KT with AR shows a decrease in miR-150-5p expression compared to NAR, suggesting that the decrease in miR-150-5p could be related to an increased MBD6 whose deregulation could have clinical consequences.

Baicalin attenuates LPS-induced alveolar type II epithelial cell A549 injury by attenuation of the FSTL1 signaling pathway via increasing miR-200b-3p expression

In China, baicalin is the main active component of Scutellaria baicalensis, which has been used in the treatment of inflammation-related diseases, such as inflammation-induced acute lung injury. However, its specific mechanism remains unclear. This study examined the protective effect of baicalin on LPS-induced inflammation injury of alveolar epithelial cell line A549 and explored its protective mechanism. Compared with the LPS-induced group, the proliferation inhibition rates of alveolar type II epithelial cell line A549 intervened by different concentrations of baicalin decreased significantly, as did the levels of inflammatory factors IL-6, IL-1β, prostaglandin 2 and TNF-α in the supernatant. The expression levels of inflammatory proteins inducible NO synthase (iNOS), NF-κB65, phosphorylated ERK (p-ERK1/2), and phosphorylated c-Jun N-terminal kinase (p-JNK1) significantly decreased, as did the protein expression of follistatin-like protein 1 (FSTL1). In contrast, expression of miR-200b-3p significantly increased in a dose-dependent manner. These results suggested that baicalin could significantly inhibit the expression of inflammation-related proteins and improve LPS-induced inflammatory injury in alveolar type II epithelial cells. The mechanism may be related to the inhibition of ERK/JNK inflammatory pathway activation by increasing the expression of miR-200b-3p. Thus, FSTL1 is the regulatory target of miR-200b-3p.

MicroRNA-150 inhibits myeloid-derived suppressor cells proliferation and function through negative regulation of ARG-1 in sepsis

AIMS

Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. The majority of sepsis-related deaths occur during late sepsis, which presents as a state of immunosuppression. Myeloid-derived suppressor cells (MDSCs) have been reported to promote immunosuppression during sepsis. Here we aim to understand the role of microRNAs in regulating MDSCs proliferation and immunosuppression function during sepsis.

MAIN METHODS

Murine sepsis model was established using cecal ligation and puncture (CLP). A microarray was used to identify microRNAs with differential expression in murine sepsis. The effect of microRNA-150 on MDSCs proliferation and function was then evaluated. 140 multiple trauma patients from Tongji Hospital and 10 healthy controls were recruited. Peripheral blood samples were taken and the serum level of miR-150 was measured.

KEY FINDINGS

In the murine model of sepsis, MDSCs expansion was noted in the spleen and bone marrow, while expression of miR-150 in MDSCs decreased. Replenishing miR-150 inhibited the expansion of MDSCs in both monocytic and polymorphonuclear subpopulations, as well as decreasing the immunosuppressive function of MDSCs, through down-regulation of ARG1. Both pro-inflammatory cytokine IL-6 and anti-inflammatory cytokines TGF-β and IL-10 were reduced by miR-150. In human, the serum level of miR-150 was down-regulated in septic patients and elevated in non-septic trauma patients compared to healthy controls.

SIGNIFICANCE

Our study showed that MiR-150 is down-regulated during sepsis. Replenishing miR-150 reduces the immunosuppression function of MDSCs by down-regulating ARG1 in late sepsis. MiR-150 might serve as a potential therapeutic option for sepsis.

Identification and Validation of Potential miRNAs, as Biomarkers for Sepsis and Associated Lung Injury: A Network-Based Approach

Sepsis is a dysregulated immune response disease affecting millions worldwide. Delayed diagnosis, poor prognosis, and disease heterogeneity make its treatment ineffective. miRNAs are imposingly involved in personalized medicine such as therapeutics, due to their high sensitivity and accuracy. Our study aimed to reveal the biomarkers that may be involved in the dysregulated immune response in sepsis and lung injury using a computational approach and in vivo validation studies. A sepsis miRNA Gene Expression Omnibus (GEO) dataset based on the former analysis of blood samples was used to identify differentially expressed miRNAs (DEMs) and associated hub genes. Sepsis-associated genes from the Comparative Toxicogenomics Database (CTD) that overlapped with identified DEM targets were utilized for network construction. In total, 317 genes were found to be regulated by 10 DEMs (three upregulated, namely miR-4634, miR-4638-5p, and miR-4769-5p, and seven downregulated, namely miR-4299, miR-451a, miR181a-2-3p, miR-16-5p, miR-5704, miR-144-3p, and miR-1290). Overall hub genes (HIP1, GJC1, MDM4, IL6R, and ERC1) and for miR-16-5p (SYNRG, TNRC6B, and LAMTOR3) were identified based on centrality measures (degree, betweenness, and closeness). In vivo validation of miRNAs in lung tissue showed significantly downregulated expression of miR-16-5p corroborating with our computational findings, whereas expression of miR-181a-2-3p and miR-451a were found to be upregulated in contrast to the computational approach. In conclusion, the differential expression pattern of miRNAs and hub genes reported in this study may help to unravel many unexplored regulatory pathways, leading to the identification of critical molecular targets for increased prognosis, diagnosis, and drug efficacy in sepsis and associated organ injuries.

The Role of MicroRNAs in Acute Respiratory Distress Syndrome and Sepsis, From Targets to Therapies: A Narrative Review

Acute respiratory distress syndrome (ARDS) is a significant cause of morbidity and mortality in the intensive care unit (ICU) and is characterized by lung epithelial and endothelial cell injury, with increased permeability of the alveolar-capillary membrane, leading to pulmonary edema, severe hypoxia, and difficulty with ventilation. The most common cause of ARDS is sepsis, and currently, treatment of ARDS and sepsis has consisted mostly of supportive care because targeted therapies have largely been unsuccessful. The molecular mechanisms behind ARDS remain elusive. Recently, a number of microRNAs (miRNAs) identified through high-throughput screening studies in ARDS patients and preclinical animal models have suggested a role for miRNA in the pathophysiology of ARDS. miRNAs are small noncoding RNAs ranging from 18 to 24 nucleotides that regulate gene expression via inhibition of the target mRNA translation or by targeting complementary mRNA for early degradation. Unsurprisingly, some miRNAs that are differentially expressed in ARDS overlap with those important in sepsis. In addition, circulatory miRNA may be useful as biomarkers or as targets for pharmacologic therapy. This can be revolutionary in a syndrome that has neither a measurable indicator of the disease nor a targeted therapy. While there are currently no miRNA-based therapies targeted for ARDS, therapies targeting miRNA have reached phase II clinical trials for the treatment of a wide range of diseases. Further studies may yield a unique miRNA profile pattern that serves as a biomarker or as targets for miRNA-based pharmacologic therapy. In this review, we discuss miRNAs that have been found to play a role in ARDS and sepsis, the potential mechanism of how particular miRNAs may contribute to the pathophysiology of ARDS, and strategies for pharmacologically targeting miRNA as therapy.

The Relationship between Extracellular/intracellular microRNAs and TLRs May Be Used as a Diagnostic and Therapeutic Approach in Sepsis

One of the leading causes of death in the intensive care unit (ICU) is sepsis. Different studies have been performed on different markers to determine the cause of sepsis. microRNAs (miRNAs) are non-coding RNAs that can be released both inside and outside the cell and regulate the target gene expression by binding to the 3' untranslated region (3'UTR) of the target genes. TLRs play an important role in innate immunity that can be modulated by biological markers such as microRNAs. In this study, we summarized the recent progress on the role of extracellular and intracellular microRNAs in sepsis. It has also been focused on the association of TLRs with extracellular and intracellular micro RNAs in the regulation of sepsis. In conclusion, this study has provided new insight into the role of microRNAs as a regulator of the TLRs which may lead to the aberrant inflammatory response in sepsis. Therefore, it suggests that both intracellular and extracellular microRNAs may play a therapeutic role in the treatment of sepsis via regulating TLRs. However, yet sepsis and septic shock are medical emergencies and further studies are needed to specify the exact role of microRNAs and TLRs in sepsis.

High expression of miR-483-5p aggravates sepsis-induced acute lung injury

Sepsis-induced acute lung injury (ALI) has high morbidity and mortality rates, and there remains a need for therapeutic methods to improve the outcome of ALI patients. miR-483-5p is an important regulator for the development of various diseases such as sepsis. Nevertheless, it is not known whether miR-483-5p has an effect on sepsis-induced ALI. To explore this issue, this study used cecal ligation and puncture (CLP)-treated mice and lipopolysaccharide (LPS)-treated pulmonary microvascular endothelial cells (PMVECs) cells to simulate the models of sepsis-induced ALI in vivo and in vitro. Pathological and histological changes of lungs from sepsis-induced ALI mice were detected by Hematoxylin-eosin staining. The detection levels of caspase-3, interleukin (IL)-6 and IL-1β were used to reflect the effect of miR-483-5p on apoptosis and inflammation of sepsis-induced ALI. The detection level of lactate dehydrogenase (LDH) in PMVECs cells was used to reflect the severe extent of sepsis-induced injury. The expression of miR-483-5p in lung tissues of sepsis-induced ALI mice was determined by qRT-PCR. In addition, the interaction of miR-483-5p with PIAS1 was identified and validated by Targetscan website and luciferase reporter assay, respectively. The results showed that miR-483-5p was up-regulated in the lung tissues of sepsis-induced ALI mice. Knockdown of miR-483-5p effectively ameliorated lung injury in mice with sepsis-induced ALI and inhibited inflammation and apoptosis of LPS-treated PMVECs cells. Furthermore, in vitro experiment revealed that PIAS1 was a potential target of miR-483-5p. Moreover, miR-483-5p could suppress PIAS1 expression to aggravate inflammation and apoptosis of LPS-treated PMVECs cells. These findings suggest miR-483-5p is a potential therapeutic and diagnostic biomarker for sepsis-induced ALI and provide a new insight for understanding the molecular mechanism of sepsis-induced ALI.

Upregulation of miR-150-5p alleviates LPS-induced inflammatory response and apoptosis of RAW264.7 macrophages by targeting Notch1

Circulating miR-150-5p has been identified as a prognostic marker in patients with critical illness and sepsis. Herein, we aimed to further explore the role and underlying mechanism of miR-150-5p in sepsis. Quantitative real-time-PCR assay was performed to detect the expression of miR-150-5p upon stimulation with lipopolysaccharide (LPS) in RAW264.7 cells. The levels of tumor necrosis factor-α, interleukin (IL)-6 and IL-1β were measured by ELISA assay. Cell apoptosis was determined using flow cytometry. Western blot was used to assess notch receptor 1 (Notch1) expression in LPS-induced RAW264.7 cells. Dual-luciferase reporter assay was employed to validate the target of miR-150-5p. Our data showed that miR-150-5p was downregulated and Notch1 was upregulated in LPS-stimulated RAW264.7 cells. miR-150-5p overexpression or Notch1 silencing alleviated LPS-induced inflammatory response and apoptosis in RAW264.7 cells. Moreover, Notch1 was a direct target of miR-150-5p. Notch1 abated miR-150-5p-mediated anti-inflammation and anti-apoptosis in LPS-induced RAW264.7 cells. miR-150-5p alleviated LPS-induced inflammatory response and apoptosis at least partly by targeting Notch1 in RAW264.7 cells, highlighting miR-150-5p as a target in the development of anti-inflammation and anti-apoptosis drugs for sepsis treatment.

Two gene set variation indexes as potential diagnostic tool for sepsis

Accurate diagnosis of sepsis remains challenging, new markers or combinations of markers are urgently needed. In the present study, we screened differentially expressed genes (DEGs) between sepsis and non-sepsis blood samples across three previously published gene expression data sets. Common upregulated and downregulated DEGs were ranked according to their average functional similarity. The ten genes (OLFM4, ORM1, CEP55, S100A12, S100P, LRG1, CEACAM8, MS4A4A, PLSCR1, and IL1R2) with the largest average functional similarity among the common upregulated genes and another ten genes (THEMIS, IL2RB, CD2, IL7R, CD3E, KLRB1, PVRIG, CCRR3, TGFBR3, and PLEKHA1) with the largest average functional similarity among the common downregulated genes were separately identified as the upregulated crucial gene set and the downregulated crucial gene set. Gene set variation analysis (GSVA) was used to obtain the GSVA index of each sample against the two crucial gene sets. Both the two crucial GSVA indexes may be robust markers for sepsis with high area under ROC curve. The diagnostic utility of the upregulated GSVA index was validated in another independent data set. Functional analyses revealed several sepsis-related pathways. In conclusion, we proposed two sepsis-related gene sets across multiple data sets and created two GSVA indexes with promising diagnostic value.

Epigenetic biomarkers for human sepsis and septic shock: insights from immunosuppression

Sepsis is a life-threatening condition that occurs when the body responds to an infection damaging its own tissues. Sepsis survivors sometimes suffer from immunosuppression increasing the risk of death. To our best knowledge, there is no 'gold standard' for defining immunosuppression except for a composite clinical end point. As the immune system is exposed to epigenetic changes during and after sepsis, research that focuses on identifying new biomarkers to detect septic patients with immunoparalysis could offer new epigenetic-based strategies to predict short- and long-term pathological events related to this life-threatening state. This review describes the most relevant epigenetic mechanisms underlying alterations in the innate and adaptive immune responses described in sepsis and septic shock, and their consequences for immunosuppression states, providing several candidates to become epigenetic biomarkers that could improve sepsis management and help predict immunosuppression in postseptic patients.

Epigenetics Mechanisms in Multiorgan Dysfunction Syndrome

Epigenetic mechanisms including deoxyribonucleic acid (DNA) methylation, histone modifications (eg, histone acetylation), and microribonucleic acids (miRNAs) have gained much scientific interest in the last decade as regulators of genes expression and cellular function. Epigenetic control is involved in the modulation of inflammation and immunity, and its dysregulation can contribute to cell damage and organ dysfunction. There is growing evidence that epigenetic changes can contribute to the development of multiorgan dysfunction syndrome (MODS), a leading cause of mortality in the intensive care unit (ICU). DNA hypermethylation, histone deacetylation, and miRNA dysregulation can influence cytokine and immune cell expression and promote endothelial dysfunction, apoptosis, and end-organ injury, contributing to the development of MODS after a critical injury. Epigenetics processes, particularly miRNAs, are emerging as potential biomarkers of severity of disease, organ damage, and prognostic factors in critical illness. Targeting epigenetics modifications can represent a novel therapeutic approach in critical care. Inhibitors of histone deacetylases (HDCAIs) with anti-inflammatory and antiapoptotic activities represent the first class of drugs that reverse epigenetics modifications with human application. Further studies are required to acquire a complete knowledge of epigenetics processes, full understanding of their individual variability, to expand their use as accurate and reliable biomarkers and as safe target to prevent or attenuate MODS in critical disease.

miRNA-5119 regulates immune checkpoints in dendritic cells to enhance breast cancer immunotherapy

Dendritic cell (DC) based immunotherapy is a promising approach to clinical cancer treatment. miRNAs are a class of small non-coding RNA molecules that bind to RNAs to mediate multiple events which are important in diverse biological processes. miRNA mimics and antagomirs may be potent agents to enhance DC-based immunotherapy against cancers. miRNA array analysis was used to identify a representative miR-5119 potentially regulating PD-L1 in DCs. We evaluated levels of ligands of immune cell inhibitory receptors (IRs) and miR-5119 in DCs from immunocompetent mouse breast tumor-bearing mice, and examined the molecular targets of miR-5119. We report that miRNA-5119 was downregulated in spleen DCs from mouse breast cancer-bearing mice. In silico analysis and qPCR data showed that miRNA-5119 targeted mRNAs encoding multiple negative immune regulatory molecules, including ligands of IRs such as PD-L1 and IDO2. DCs engineered to express a miR-5119 mimic downregulated PD-L1 and prevented T cell exhaustion in mice with breast cancer homografts. Moreover, miR-5119 mimic-engineered DCs effectively restored function to exhausted CD8⁺ T cells in vitro and in vivo, resulting in robust anti-tumor cell immune response, upregulated cytokine production, reduced T cell apoptosis, and exhaustion. Treatment of 4T1 breast tumor-bearing mice with miR-5119 mimic-engineered DC vaccine reduced T cell exhaustion and suppressed mouse breast tumor homograft growth. This study provides evidence supporting a novel therapeutic approach using miRNA-5119 mimic-engineered DC vaccines to regulate inhibitory receptors and enhance anti-tumor immune response in a mouse model of breast cancer. miRNA/DC-based immunotherapy has potential for advancement to the clinic as a new strategy for DC-based anti-breast cancer immunotherapy.

Identification of suitable controls for miRNA quantification in T-cells and whole blood cells in sepsis

Complex immune dysregulation is a hallmark of sepsis. The occurring phases of immunosuppression and hyperinflammation require rapid detection and close monitoring. Reliable tools to monitor patient’s immune status are yet missing. Currently, microRNAs are being discussed as promising new biomarkers in sepsis. However, no suitable internal control for normalization of miRNA expression by qPCR has been validated so far, thus hampering their potential benefit. We here present the first evaluation of endogenous controls for miRNA analysis in human sepsis. Novel candidate reference miRNAs were identified via miRNA microArray. TaqMan qPCR assays were performed to evaluate these microRNAs in T-cells and whole blood cells of sepsis patients and healthy controls in two independent cohorts. In T-cells, U48 and miR-320 proved suitable as endogenous controls, while in whole blood cells, U44 and miR-942 provided best stability values for normalization of miRNA quantification. Commonly used snRNA U6 exhibited worst stability in all sample groups. The identified internal controls have been prospectively validated in independent cohorts. The critical importance of housekeeping gene selection is emphasized by exemplary quantification of imuno-miR-150 in sepsis patients. Use of appropriate internal controls could facilitate research on miRNA-based biomarker-use and might even improve treatment strategies in the future.

Serum Levels of miR-143 Predict Survival in Critically Ill Patients

Background and Aims

Recent data suggested a potential role of miR-143 as a biomarker for systemic inflammation and infection. However, its role in critical illness and sepsis is only poorly understood.

Methods

We determined circulating levels of miR-143 in 218 critically ill patients, of which 135 fulfilled sepsis criteria, and compared them to 76 healthy controls. Results were correlated with clinical records.

Results

In the total cohort of critically ill patients from a medical intensive care unit (ICU), miR-143 serum levels tended to be lower compared to healthy control samples, but this difference did not reach statistical significance. In ICU patients, serum levels of miR-143 were independent of disease etiology, including the presence of sepsis, or severity of disease. Importantly, low miR-143 serum levels were associated with an unfavorable short- and long-term prognosis in ICU patients. Our study identified different optimal cut-off values at which low miR-143 serum levels predicted mortality with a high diagnostic accuracy. In line with this, concentrations of circulating miR-143 correlated with markers of organ failure such as creatinine, bilirubin, or lactate in our cohort of critically ill patients.

Conclusion

Low miR-143 serum levels are indicative for an unfavorable short- and long-term prognosis in critically ill patients admitted to a medical ICU. Our data suggest a previously unrecognized role for miR-143 measurements as a novel prognostic marker in critically ill patients.