Xenon Protects Against Septic Acute Kidney Injury via miR-21 Target Signaling Pathway

The role of N6-methyladenosine (m6A) in kidney diseases

Chemical modifications are a specific and efficient way to regulate the function of biological macromolecules. Among them, RNA molecules exhibit a variety of modifications that play important regulatory roles in various biological processes. More than 170 modifications have been identified in RNA molecules, among which the most common internal modifications include N6-methyladenine (m6A), n1-methyladenosine (m1A), 5-methylcytosine (m5C), and 7-methylguanine nucleotide (m7G). The most widely affected RNA modification is m6A, whose writers, readers, and erasers all have regulatory effects on RNA localization, splicing, translation, and degradation. These functions, in turn, affect RNA functionality and disease development. RNA modifications, especially m6A, play a unique role in renal cell carcinoma disease. In this manuscript, we will focus on the biological roles of m6A in renal diseases such as acute kidney injury, chronic kidney disease, lupus nephritis, diabetic kidney disease, and renal cancer.

Roles of noncoding RNAs in septic acute kidney injury

Septic acute kidney injury (SAKI) is one of the most common and life-threatening complications of sepsis. Patients with SAKI have increased mortality. However, the underlying pathogenesis is unclear, and the treatment targeting SAKI is unsatisfactory. Thus, identifying optimal biomarkers for SAKI diagnosis and treatment is an urgent requisite. Accumulating evidence indicates that noncoding RNAs (ncRNAs) are involved in the occurrence and progression of SAKI. In the present review, we summarized the studies of ncRNAs in SAKI, including microRNAs (miRNAs), long ncRNAs (lncRNAs), and circular RNAs (circRNAs). The ncRNAs are divided into protective and damage factors according to their role in SAKI, and their expression patterns, functions, and molecular mechanisms were elaborated. Next, we proposed that ncRNAs have the potential to be diagnostic and prognostic biomarkers for SAKI and as new therapeutic targets. This review aimed to provide a comprehensive overview of ncRNAs in SKAI and explored the clinical value of ncRNAs as ideal biomarkers of SAKI.

Injury Site Specific Xenon Delivered by Platelet Membrane-Mimicking Hybrid Microbubbles to Protect Against Acute Kidney Injury via Inhibition of Cellular Senescence

Inhalation of xenon gas improves acute kidney injury (AKI). However, xenon can only be delivered through inhalation, which causes non-specific distribution and low bioavailability of xenon, thus limiting its clinical application. In this study, xenon is loaded into platelet membrane-mimicking hybrid microbubbles (Xe-Pla-MBs). In ischemia-reperfusion-induced AKI, intravenously injected Xe-Pla-MBs adhere to the endothelial injury site in the kidney. Xe-Pla-MBs are then disrupted by ultrasound, and xenon is released to the injured site. This release of xenon reduced ischemia-reperfusion-induced renal fibrosis and improved renal function, which are associated with decreased protein expression of cellular senescence markers p53 and p16, as well as reduced beta-galactosidase in renal tubular epithelial cells. Together, platelet membrane-mimicking hybrid microbubble-delivered xenon to the injred site protects against ischemia-reperfusion-induced AKI, which likely reduces renal senescence. Thus, the delivery of xenon by platelet membrane-mimicking hybrid microbubbles is a potential therapeutic approach for AKI.

MicroRNAs in septic acute kidney injury

Sepsis is a potentially fatal complication of burns and trauma that can cause acute kidney injury (AKI) with substantial morbidity and mortality, but this disease is poorly understood. Despite medical advances, effective therapeutic regimens for septic AKI remain uncommon. MicroRNAs (miRNAs) are endogenous non-coding RNAs that influence the translation of target messenger RNAs in a variety of biological processes. Emerging evidence has shown that miRNAs are intimately associated with septic AKI. The goal of this review was to summarize recent advances in the profound understanding of the functional role of miRNAs in septic AKI, as well as to provide new insights into miRNAs as feasible biomarkers and therapeutic targets for septic AKI.

NIR-II Photoacoustic-Active DNA Origami Nanoantenna for Early Diagnosis and Smart Therapy of Acute Kidney Injury

Herein, we designed and synthesized a novel microRNA (miR)-responsive nanoantenna capable of early diagnosis and smart treatment of acute kidney injury (AKI). The nanoantenna was made of two miniature gold nanorods (AuNRs) (e.g., length: ∼48 nm; width: ∼9 nm) linked together by a rectangular DNA origami nanostructure (rDONs) scaffold (e.g., length: ∼90 nm; width: ∼60 nm) (rDONs@AuNR dimer). The surface plasmon resonance peak of the constructed nanoantenna is located within the NIR-II window (e.g., ∼1060 nm), thus guaranteeing photoacoustic (PA) imaging of the nanoantenna in deep tissues. Intriguingly, the nanoantenna displayed exclusive kidney retention in both healthy mice and ischemia reperfusion-induced AKI mice by leveraging the kidney-targeting ability of rDONs. Distinguished from the stable signals in the healthy mice, the PA signals of the nanoantenna would turn down in the AKI mice due to the AuNR detached from rDONs upon interaction with miR-21, which were up-expressed in AKI mice. The limit of detection toward miR-21 was down to 2.8 nM, enabling diagnosis of AKI as early as 10 min post-treatment with ischemia reperfusion, around 2 orders of magnitude earlier than most established probes. Moreover, the naked rDON scaffold generated by AKI could capture more reactive oxygen species (e.g., 1.5-fold more than rDONs@AuNR dimer), alleviating ischemic AKI. This strategy provided a new avenue for early diagnosis and smart treatment of AKI.

Xenon attenuated neonatal lipopolysaccharide exposure induced neuronal necroptosis and subsequently improved cognition in juvenile rats

Background: Neonatal sepsis is known to cause neurodevelopment impairment and has been reported to increase risks for neurological/psychiatric disorders. In this study, we investigated the effect of xenon, a well-known potent neuroprotective gas, on neonatal sepsis-induced neurodevelopment impairment in rats together with underlying mechanism by focusing on receptor-interacting protein kinase (RIP) mediated neuronal necroptosis. Methods: 3-day-old Sprague-Dawley rat pups were exposed to either 70% xenon or N2 balanced with O2 for 6 h, during which lipopolysaccharide (LPS) was injected intraperitoneally for 3 times (500 μg/kg for the 1st and 250 μg/kg for the second and third dose; n = 6-10/group). In another cohort of 3-day-old rat pups, intracerebroventricular injection of necrostatin-1 (4 µg in 4 µl saline, a RIP-1-targeted inhibitor of necroptosis) was performed 20 min after the third dose of LPS. The learning ability and memory were assessed 25 days after LPS injection. Then, their hippocampus was collected for neuronal necroptosis with RIP and MIKL assessments using western blot and in situ immunostaining. Systemic and neuro-inflammation was also assessed. Results: LPS insult resulted in elevation of pro-inflammatory cytokine TNF-𝝰 and IL-6, caused neuronal necroptosis and damaged synaptic integrity at the brain developing stage, which finally led to the long-term cognitive impairment. Xenon inhibited necroptosis associated mediator RIP-1, RIP-3, and MLKL activation, protected neurons and attenuated cognitive dysfunction induced by LPS. Like xenon, the similar pattern changes induced by a RIP-1 inhibitor Necrostatin-1 were also found. Conclusion: This study indicates that necroptosis is involved in neonatal sepsis-induced neurofunctional impairments and xenon may be a novel therapeutic strategy to prevent/treat cognitive impairment in neonatal septic patients.

Inhibition of Phosphoinositide 3-Kinase Gamma Protects Endothelial Cells via the Akt Signaling Pathway in Sepsis-Induced Acute Kidney Injury

INTRODUCTION

Sepsis is a primary cause of death in critically ill patients and is characterized by multiple organ dysfunction, including sepsis-induced acute kidney injury (AKI), which contributes to high mortality in sepsis. However, its pathophysiological mechanisms remain unclear. The kidney has one of the richest and most diversified endothelial cell populations in the body. This study was designed to investigate the effects of endothelial dysfunction in sepsis-induced AKI and explore possible intervention measures to offer new insight into the pathogenesis and treatment of sepsis-induced AKI.

METHODS

The circulating levels of endothelial adhesion molecules were detected in patients with sepsis and healthy controls to observe the role of endothelial damage in sepsis and sepsis-induced AKI. A murine sepsis model induced by cecal ligation and perforation was pretreated with a phosphoinositide 3-kinase gamma (PI3Kγ) inhibitor (CZC24832), and survival, kidney damage, and renal endothelial injury were assessed by pathological examination, immunohistochemistry, quantitative polymerase chain reaction, and Western blotting. Lipopolysaccharides and CZC24832 were administered to human umbilical vein endothelial cells in vitro, and endothelial cell function and the expression of adhesion molecules were evaluated.

RESULTS

Endothelial damage was more serious in sepsis-induced AKI than that in non-AKI, and the inhibition of PI3Kγ alleviates renal endothelial injury in a murine sepsis model, protecting endothelial cell function and repairing endothelial cell injury through the Akt signaling pathway.

CONCLUSIONS

In this study, endothelial cell dysfunction plays an important role in sepsis-induced AKI, and the inhibition of PI3Kγ alleviates endothelial cell injury in sepsis-induced AKI through the PI3Kγ/Akt pathway, providing novel targets for treating sepsis and related kidney injury.

LncRNA IRAR regulates chemokines production in tubular epithelial cells thus promoting kidney ischemia-reperfusion injury

Increasing evidence demonstrates that long noncoding RNAs (lncRNAs) play an important role in several pathogenic processes of the kidney. However, functions of lncRNAs in ischemic acute kidney injury (AKI) remain undefined. In this study, global lncRNA profiling indicated that many lncRNA transcripts were deregulated in kidney after ischemia reperfusion (IR). Among them, we identified IRAR (ischemia-reperfusion injury associated RNA) as a potential lncRNA candidate, which was mostly expressed by the tubular epithelial cells (TECs) after IR, involved in the development of AKI. GapmeR-mediated silencing and viral-based overexpression of IRAR were carried out to assess its function and contribution to IR-induced AKI. The results revealed that in vivo silencing of IRAR significantly reduced IR-induced proinflammatory cells infiltration and AKI. IRAR overexpression induced chemokine CCL2, CXCL1 and CXCL2 expression both in mRNA and protein levels in TECs, while, silencing of IRAR resulted in downregulation of these chemokines. RNA immunoprecipitation and RNA pulldown assay validated the association between IRAR and CCL2, CXCL1/2. Further examination revealed that specific ablation of CCL2 in TECs reduced macrophages infiltration and proinflammatory cytokine production, attenuated renal dysfunction in IR mice. Inhibition of CXC chemokine receptor 2 (receptor of CXCL1/2) reduced neutrofils infiltration, but had no overt effect on kidney function. To explore the mechanism of IRAR upregulation in kidney during IR, we analyzed promoter region of IRAR and predicted a potential binding site for transcription factor C/EBP β on IRAR promoter. Silencing of C/EBP β reduced IRAR expression in TECs. A dual-luciferase reporter assay and chromatin immunoprecipitation (ChIP) confirmed that IRAR was a transcriptional target of the C/EBP β. Altogether, our findings identify IRAR as a new player in the development of ischemic AKI through regulating chemokine production and immune cells infiltration, suggesting that IRAR is a potential target for prevention and/or attenuation of AKI.

Chemokine CCL2 from proximal tubular epithelial cells contributes to sepsis-induced acute kidney injury

Damage-associated molecular patterns secreted from activated kidney cells initiate inflammatory response, a critical step in the development of sepsis-induced acute kidney injury (AKI). However, the underlying mechanism remains to be clarified. Here, we established a mouse model of sepsis-induced AKI through intraperitoneal injection of lipopolysaccharide (LPS), and demonstrated that LPS induced dramatical upregulation of C-C motif chemokine ligand 2 (CCL2) at both the mRNA and the protein levels in kidney, which was mainly expressed by tubular epithelial cells (TECs), especially by proximal TECs. Proximal tubule-specific ablation of CCL2 reduced LPS-induced macrophage infiltration, proinflammatory cytokine expression, and attenuated AKI. In vitro, using transwell migration assay, we found that deficiency of CCL2 in TECs decreased macrophage migration ability. However, myeloid-specific depletion of CCL2 could not protect the kidneys from the aforementioned effects. Mechanistically, LPS activated toll like receptor (TLR) 2 signaling in TECs, which induced activation of its downstream effector nuclear factor (NF)-κB. Blockade of TLR2 signaling or inhibition of NF-κB activation in TECs significantly suppressed LPS-induced CCL2 expression. Furthermore, ChIP analyses confirmed a direct binding of NF-κB p65 in the CCL2 promoter regein, and LPS increased the binding of NF-κB p65 to CCL2 promoter, suggesting that TLR2/NF-κB p65 regulates CCL2 expression in TECs. Together, these results demonstrate that endogenous CCL2 released from PTECs, not from myeloid cells was responsible for sepsis-induced kidney inflammation and AKI. Specificly targeting tubular TLR2/NF-κB/CCL2 signaling may be a potential therapeutic strategy for prevention or attenuation of septic AKI.

Non-Coding RNAs in Sepsis-Associated Acute Kidney Injury

Sepsis is a systemic inflammatory response caused by a severe infection that leads to multiple organ damage, including acute kidney injury (AKI). In intensive care units (ICU), the morbidity and mortality associated with sepsis-associated AKI (SA-AKI) are gradually increasing due to lack of effective and early detection, as well as proper treatment. Non-coding RNAs (ncRNAs) exert a regulatory function in gene transcription, RNA processing, post-transcriptional translation, and epigenetic regulation of gene expression. Evidence indicated that miRNAs are involved in inflammation and programmed cell death during the development of sepsis-associated AKI (SA-AKI). Moreover, lncRNAs and circRNAs appear to be an essential regulatory mechanism in SA-AKI. In this review, we summarized the molecular mechanism of ncRNAs in SA-AKI and discussed their potential in clinical diagnosis and treatment.

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

INTRODUCTION

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Endothelial progenitor cells-derived exosomal microRNA-21-5p alleviates sepsis-induced acute kidney injury by inhibiting RUNX1 expression

The role of microRNA-21-5p (miR-21-5p) in sepsis-induced acute kidney injury (AKI) has been seldom discussed. Therefore, the objective of this present study was to investigate the mechanism of endothelial progenitor cells-derived exosomes (EPCs-exos) in sepsis-induced AKI via miR-21-5p/runt-related transcription factor 1 (RUNX1) axis. miR-21-5p was downregulated and RUNX1 was upregulated in the kidney of cecal ligation and puncture (CLP) rats, and miR-21-5p targeted RUNX1. Elevation of miR-21-5p improved renal function and renal tissue pathological damage, attenuated serum inflammatory response, as well as reduced apoptosis and oxidative stress response in renal tissues, and regulated endothelial glycocalyx damage marker proteins syndecan-1 and heparanase-1 in CLP rats. Overexpression of RUNX1 abolished the impacts of elevated miR-21-5p in CLP rats. Also, EPCs-exos upregulated miR-21-5p expression, and functioned similar to elevation of miR-21-5p for CLP rats. Downregulating miR-21-5p partially reversed the effects of EPCs-exos on sepsis-induced AKI. Collectively, our study suggests that EPCs release miR-21-5p-containing exosomes to alleviate sepsis-induced AKI through RUNX1 silencing.

Gene deficiency or pharmacological inhibition of PDCD4-mediated FGR signaling protects against acute kidney injury

Recent studies have shown that programmed cell death 4 (PDCD4) modulates distinct signal transduction pathways in different pathological conditions. Despite acute and chronic immune responses elicited by ischemia contributing to the functional deterioration of the kidney, the contributions and mechanisms of PDCD4 in acute kidney injury (AKI) have remained unclear. Using two murine AKI models including renal ischemia/reperfusion injury (IRI) and cisplatin-induced AKI, we found that PDCD4 deficiency markedly ameliorated renal dysfunction and inflammatory responses in AKI mice. Consistently, upregulation of PDCD4 was also confirmed in the kidneys from patients with biopsy confirmed acute tubular necrosis from a retrospective cohort study. Moreover, we found that overexpression of Fgr, a member of the tyrosine kinase family, dramatically aggravated renal injury and counteracted the protective effects of PDCD4 deficiency in AKI mice. We discovered that FGR upregulated NOTCH1 expression through activating STAT3. Most importantly, we further found that systemic administration of ponatinib, a tyrosine kinase inhibitor, significantly ameliorated AKI in mice. In summary, we identified that PDCD4 served as an important regulator, at least in part, of FGR/NOTCH1-mediated tubular apoptosis and inflammation in AKI mice. Furthermore, our findings suggest that ponatinib-mediated pharmacologic targeting of this pathway had therapeutic potential for mitigating AKI.

MicroRNAs as Biomarkers and Therapeutic Targets in Inflammation- and Ischemia-Reperfusion-Related Acute Renal Injury

Acute kidney injury (AKI), caused mainly by ischemia-reperfusion, sepsis, or nephrotoxins (such as contrast medium), is identified by an abrupt decline in kidney function and is associated with high morbidity and mortality. Despite decades of efforts, the pathogenesis of AKI remains poorly understood, and effective therapies are lacking. MicroRNAs (miRNAs) are small noncoding RNAs that regulate gene expression at the posttranscriptional level to control cell differentiation, development, and homeostasis. Additionally, extracellular miRNAs might mediate cell-cell communication during various physiological and pathological processes. Recently, mounting evidence indicates that miRNAs play a role in the pathogenesis of AKI. Moreover, emerging research suggests that because of their remarkable stability in body fluids, microRNAs can potentially serve as novel diagnostic biomarkers of AKI. Of note, our previous finding that miR-494 is rapidly elevated in urine but not in serum provides insight into the ultimate role of urine miRNAs in AKI. Additionally, exosomal miRNAs derived from stem cells, known as the stem cell secretome, might be a potential innovative therapeutic strategy for AKI. This review aims to provide new data obtained in this field of research. It is hoped that new studies on this topic will not only generate new insights into the pathophysiology of urine miRNAs in AKI but also might lead to the precise management of this fatal disease.

LncRNA GAS5 promotes apoptosis as a competing endogenous RNA for miR-21 via thrombospondin 1 in ischemic AKI

Mounting evidence has indicated that long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) played important roles in renal ischemia/reperfusion (I/R) injury. However, the involvement of lncRNA growth arrest specific 5 (GAS5) in acute kidney injury (AKI) remained largely unexplored. This study aimed to determine possible mechanisms of GAS5 in the renal I/R process. We found that GAS5, noticeably upregulated by renal I/R injury, was further suppressed by delayed IPC while knockdown of miR-21 in vivo before IPC could significantly increased the GAS5 levels. Concurrently, TSP-1 was negatively regulated by miR-21 in vivo and vitro. Additionally, Reciprocal repression of GAS5 and miR-21 was identified. Knockdown of miR-21 in H6R0.5 treated HK-2 cells promoted apoptosis. Co-transfection of miR-21 mimic and pcDNA-GAS5 or pcDNA-Vector were performed, results of which showed that inhibition of miR-21 on TSP-1 could be rescued by overexpression of GAS5. This study suggested that GAS5 facilitated apoptosis by competitively sponging miR-21, which negatively regulated TSP-1 in renal I/R injury. This novel regulatory axis could act as a therapeutic target for AKI in the future.

The crosstalk between hypoxia-inducible factor-1α and microRNAs in acute kidney injury

Acute kidney injury (AKI) is a common critical clinical disease that is characterized by a rapid decline in renal function and reduced urine output. Ischemia and hypoxia are dominant pathophysiological changes in AKI that are induced by many factors, and the role of the “master” regulator hypoxia-inducible factor-1α (HIF-1α) is well recognized in AKI-related studies. MicroRNAs have been found to act as critical regulators of AKI pathophysiological process. More studies now have reported mutual interactions between HIF-1α and microRNAs in AKI. Therefore, in this brief review, we look into the mutual regulatory mechanisms between HIF-1α and microRNAs and discuss their function in the process of AKI. Recent studies demonstrated that HIF-1α is involved in the regulation of multiple functional microRNAs in AKI, and in turn, the level of HIF-1α is regulated by specific microRNAs. However, the role of the interactions between HIF-1α and microRNAs in AKI are controversial, and whether interventions targeting relevant mechanisms could achieve clinical benefits is not clear. Much work remains to further explore the value of targeting the HIF-1α-microRNA pathway in AKI treatment.

Impact statement

At first, we have discussed the role of hypoxia-inducible factor-1α (HIF-1α) and microRNAs in the acute kidney injury (AKI) pathophysiology. Then we have summarized the interactions between HIF-1α and microRNAs reported by AKI-related studies and concluded their regulatory effects in AKI process. Finally, we have made a vision of HIF-1α/microRNAs pathway’s potential as the intervention target in AKI. The mini review provides a systematic understanding of the crosstalk between HIF-1α and microRNAs in AKI and their effects on AKI pathophysiology and treatment.

Closed circuit xenon delivery for 72h in neonatal piglets following hypoxic insult using an ambient pressure automated control system: Development, technical evaluation and pulmonary effects

BACKGROUND

Therapeutic hypothermia (TH) for 72h is the standard treatment following neonatal encephalopathy (NE). However, one-third do not benefit and adjunctive therapies are urgently needed. Xenon enhances neuroprotection with TH when administered at 50% concentration within 5hours of hypoxia in experimental studies. Delayed initiation (~10 hours of age) of 30% xenon for 24 hours during TH did not improve early adverse biomarkers in a clinical trial of Xenon+TH vs TH. After hypoxia-ischemia, excitotoxic injury via N-methyl-D-aspartate receptor overactivation lasts days. Since xenon partially inhibits this receptor, we hypothesised that giving 50% xenon throughout the entire 72h TH and rewarming periods would enhance neuroprotection. Xenon costs $30/litre, so a closed-circuit breathing system is desirable with automated fresh gas delivery.

METHODS

Seven mechanically ventilated newborn pigs were randomized to receive 50% inhaled xenon for 72h during hypothermia (rectal-temperature 35°C) and subsequent rewarming following a global hypoxic-ischemic insult (XeHT, N = 4) or under normothermia for 72h (rectal-temperature 38.5°C) following sham insult (XeNT, N = 3). An automated fresh gas delivery system injected oxygen/air/xenon boluses into a closed-circuit based on measured gas concentrations.

RESULTS AND DISCUSSION

Median (IQR) xenon consumption was 0.31 L/h (0.18, 0.50) and 0.34L/h (0.32, 0.49) for hypothermic and normothermic groups respectively, 0.34L/h (0.25, 0.53) overall. 92% of 9626 xenon and 69% of 9635 oxygen measurements were within 20% variation from targets. For xenon concentration, the median absolute performance errors for the XeHT and XeNT groups were 6.14% and 3.84% respectively and 4.31% overall. For oxygen these values were 13.42%, 15.05% and 12.4% respectively. There were no adverse pulmonary pathophysiology findings. Clinical problems over the total period included three related to sensors, seven breathing system leaks, ten partial and one complete tracheal tube occlusion episodes.

CONCLUSION

The automated controller functioned as intended maintaining an inhaled xenon concentration close to the 50% target for 72-78h at a xenon cost of $11.1/h.

CircNr1h4 regulates the pathological process of renal injury in salt-sensitive hypertensive mice by targeting miR-155-5p

Circular RNAs are a class of widespread and diverse endogenous RNAs that may regulate gene expression in various diseases, but their regulation and function in hypertensive renal injury remain unclear. In this study, we generated ribosomal‐depleted RNA sequencing data from normal mouse kidneys and from injured mouse kidneys induced by deoxycorticosterone acetate‐salt hypertension and identified at least 4900 circRNA candidates. A total of 124 of these circRNAs were differentially expressed between the normal and injured kidneys. Furthermore, we characterized one abundant circRNA, termed circNr1h4, which is derived from the Nr1h4 gene and significantly down‐regulated in the injured kidneys. RNA sequencing data and qPCR analysis also showed many microRNAs and mRNAs, including miR‐155‐5p and fatty acid reductase 1 (Far1), were differentially expressed between the normal and injured kidney and related to circNr1h4. In vitro, the silencing of circNr1h4 or overexpression of miR‐155‐5p significantly decreased Far1 levels and increased reactive oxygen species. Mechanistic investigations indicated that circNr1h4 acts as a competing endogenous RNA for miR‐155‐5p, leading to regulation of its target gene Far1. Our study provides novel insight into the molecular mechanisms underlying kidney injury in hypertension, which will be required to develop therapeutic strategies of targeting circRNAs for hypertensive kidney injury.

The predictive value of microRNA-21 for sepsis risk and its correlation with disease severity, systemic inflammation, and 28-day mortality in sepsis patients

Background

This study aimed to investigate the value of microRNA (miR)‐21 for predicting sepsis risk and its correlation with inflammation, disease severity as well as 28‐day mortality in sepsis patients.

Methods

Totally, 219 sepsis patients and 219 healthy controls (HCs) were recruited. Plasma samples were obtained from sepsis patients within 24 hours after admission and from HCs at the enrollment to detect miR‐21 expressions by real‐time quantitative polymerase chain reaction. Besides, the clinical characteristics of sepsis patients were recorded and the 28‐day mortality of sepsis patients was evaluated.

Results

MiR‐21 expression was decreased in sepsis patients compared with HCs, and further receiver operating characteristic (ROC) curve analysis revealed that miR‐21 was of a good value in predicting sepsis risk (area under the curve [AUC]: 0.801, 95% CI: 0.758‐0.844). Besides, miR‐21 expression was negatively associated with acute pathologic and chronic health evaluation II (APACHE II) and sequential organ failure assessment (SOFA) score in sepsis patients. Furthermore, miR‐21 expression was negatively correlated with serum creatinine, C‐reactive protein, tumor necrosis factor‐α, interleukin (IL)‐1β, IL‐6, and IL‐17, while positively correlated with albumin in sepsis patients. However, there was no correlation of miR‐21 expression with white blood cell, smoke, or comorbidities in sepsis patients. Additionally, ROC curve analysis displayed that miR‐21 exhibited a poor predictive value for 28‐day mortality risk in sepsis patients (AUC: 0.588, 95% CI: 0.505‐0.672).

Conclusion

MiR‐21 might serve as a potential biomarker for the development and progression of sepsis, while not for prognosis prediction in sepsis patients.

Liang-Ge-San, a Classic Traditional Chinese Medicine Formula, Attenuates Lipopolysaccharide-Induced Acute Lung Injury Through Up-Regulating miR-21

Background: Acute lung injury (ALI) is a life-threatening disease without effective chemotherapy at present. Liang-Ge-San (LGS) is a famous traditional Chinese medicine formula, which is used to treat ALI in China. However, only a few studies have addressed the mechanisms of LGS in ALI. Purpose: To evaluate the anti-inflammatory effects of LGS on lipopolysaccharide (LPS)-induced ALI, and to explore its underlying molecular mechanism. Methods: Murine RAW264.7 cells were treated with LGS and LPS (1 μg/ml). The generation of IL-6, TNF-α, IL-1β was detected by ELISA. The protein expressions of STAT3 and P-STAT3 (Tyr705) were determined by Western blotting and fluorescence confocal microscopy. STAT3 transcriptional activity was investigated by luciferase reporter gene assay. qPCR was used to detect the expressions of microRNA-21 (miR-21), STAT3, and IL-6. DSS cross-linking assay was used to assess the change of STAT3 dimer. In vivo anti-inflammatory effects of LGS were evaluated in an ALI mouse model induced by tracheal instillation of LPS (3 mg/kg). The anti-ALI effects were evaluated by ELISA, qPCR, Western blotting, BCA, and H&E assays. Results: LGS suppressed LPS-stimulated IL-6, TNF-α, and IL-1β generation in murine macrophages RAW264.7. Moreover, LGS down-regulated protein levels of P-STAT3 (Tyr705) and STAT3, inhibited STAT3 transcriptional activity, and up-regulated miR-21. Furthermore, blockage of miR-21 antagonized the inhibitory effects of LGS on the production of IL-6 and the expressions of P-STAT3 (Tyr705) and STAT3 as well as the formation of STAT3 dimer. Critically, LGS up-regulated the expression of miR-21 and inhibited the protein expressions of STAT3 and P-STAT3 (Tyr705) to reduce the release of IL-6 and inflammatory cell infiltration as well as the degree of edema in LPS-induced ALI mice. Conclusion: LGS inhibited LPS-induced ALI through up-regulating miR-21 and subsequently inhibiting the STAT3 signaling pathway, thereby decreasing the release of IL-6.

Uncoupling protein 1 inhibits mitochondrial reactive oxygen species generation and alleviates acute kidney injury

BACKGROUND

Uncoupling protein 1 (UCP1) is predominantly found in brown adipose tissue mitochondria, and mediates energy dissipation to generate heat rather than ATP via functional mitochondrial uncoupling. However, little is known about its expression and function in kidney.

METHODS

We carried out a mRNA microarray analysis in mice kidneys with ischemia reperfusion (IR) injury. The most dramatically downregulated gene UCP1 after IR was identified, and its role in generation of mitochondrial reactive oxygen species (ROS) and oxidative stress injury was assessed both in vitro and in vivo. Genetic deletion of UCP1 was used to investigate the effects of UCP1 on ischemia or cisplatin-indued acute kidney injury (AKI) in mice.

FINDINGS

UCP1 was located in renal tubular epithelial cells in kidney and downregulated in a time-dependent manner during renal IR. Deletion of UCP1 increased oxidative stress in kidneys and aggravated ischemia or cisplatin induced AKI in mice.Viral-based overexpression of UCP1 reduced mitochondrial ROS generation and apoptosis in hypoxia-treated tubular epithelial cells. Furthermore, UCP1 expression was regulated by peroxisome proliferator-activator receptor (PPAR) γ in kidneys during renal IR. Overexpression of PPAR-γ resembled UCP1-overexpression phenotype in vitro. Treatment with PPAR-γ agonist could induce UCP1 upregulation and provide protective effect against renal IR injury in UCP1^+/+mice, but not in UCP1^-/-mice.

INTERPRETATION

UCP1 protects against AKI likely by suppressing oxidative stress, and activation of UCP1 represents a potential therapeutic strategy for AKI. FUND: National Natural Science Foundation of China grants, Science and Technology Commission of Shanghai.

Pretreatment With Argon Protects Human Cardiac Myocyte-Like Progenitor Cells from Oxygen Glucose Deprivation-Induced Cell Death by Activation of AKT and Differential Regulation of Mapkinases

BACKGROUND

The noble gas argon induces cardioprotection in a rabbit model of myocardial ischemia and reperfusion. However, no studies in human primary cells or subjects have been performed so far. We used human cardiac myocyte-like progenitor cells (HCMs) to investigate the protective effect on the cellular level.

METHODS

HCMs were pretreated with 30% or 50% argon before oxygen-glucose deprivation (OGD) and reperfusion. We evaluated apoptotic states by flow cytometry and the activation of mitogen-activated protein kinase (MAPKs) members extracellular signal-regulated kinase (ERK), c-jun N-terminal kinase (JNK), p38 MAPkinase, and protein kinase B (Akt) by Westernblot analysis and by activity assays of downstream transcription factors. Specific inhibitors were used to proof a significant participation of these pathways in the protection by argon. Beneficial effects were further assessed by TdT-mediated dUTP-biotin nick end labeling (TUNEL) assay, lactate dehydrogenase (LDH), mitochondrial deoxyribonucleic acid (mtDNA), and cytokine release.

RESULTS

Pretreatment with 30% or 50% argon for 90 min before OGD resulted in a significant protection of HCMs against apoptosis. This effect was reversed by the application of MAPK and Akt inhibitors during argon exposure. Argon 30% reduced the release of LDH by 33% and mtDNA by 45%. The release of interleukin 1β was reduced by 44% after OGD and more than 90% during reperfusion.

CONCLUSIONS

Pretreatment with argon protects HCMs from apoptosis under ischemic conditions via activation of Akt, Erk, and biphasic regulation of JNK. Argon gas is cheap and easily administrable, and might be a novel therapy to reduce myocardial ischemia-reperfusion injury.

Potential protective effects of Dapagliflozin in gentamicin induced nephrotoxicity rat model via modulation of apoptosis associated miRNAs

BACKGROUND

Drug-induced kidney injury (DIKI) can be manifested with progressive chronic kidney diseases or end-stage renal diseases. Understanding the molecular disarrangements caused by DIKI is an attractive point of interest. A class of non-coding RNA called microRNAs (miRNAs) is known to play a major role in regulation of gene expression and signaling pathways making miRNAs excellent targets for new therapeutic agents.

AIM OF THE STUDY

We aimed to investigate the role of miRNA 21 and 181a in gentamicin (GNT) induced nephrotoxicity rat model and the protective effect of Dapagliflozin (DAPA) in modulating their expression through studying its effect on renal function as well as renal histopathological changes.

MATERIALS AND METHODS

Wistar rats were used and divided into: naïve, DAPA, GNT and DAPA + GNT groups. In all studied groups, kidney function, oxidative stress, apoptosis markers and miRNAs' expression in serum and renal biopsies were investigated in addition to the histopathological studies to identify its early renoprotective effect.

RESULTS

DAPA was found to improve kidney function, oxidative stress markers, decrease apoptosis of renal tubular cells and increase miR-21 but decrease the expression of miR-181a with restoration of the renal architecture after 14 days of treatment in GNT induced nephrotoxicity rat model.

CONCLUSIONS

DAPA produced significant decrease in renal expression of miR-181a on the other hand it increased the expression of renal miR-21, this may introduce a novel early protective effect of DAPA against GNT-induced nephrotoxicity.

Circulating miR-21, miR-210 and miR-146a as potential biomarkers to differentiate acute tubular necrosis from hepatorenal syndrome in patients with liver cirrhosis: a pilot study

BACKGROUND

Acute kidney injury (AKI) in cirrhotic patients may be functional (hepatorenal syndrome [HRS]) or structural (acute tubular necrosis [ATN]). The differentiation between these two conditions remains challenging; no definite biomarker with a clear cutoff value had been declared. miRNAs seem to be attractive innovative biomarkers to identify the nature of kidney injury in cirrhotic patients. This study aimed to investigate the possibility of using miR-21, miR-210 and miR-146a as differentiating markers between HRS and ATN.

METHODS

This pilot case control study included 50 patients with liver cirrhosis; 25 with HRS and another 25 with ATN beside 30 healthy controls. Real-time qPCR was used to measure the circulating miRNA tested.

RESULTS

Higher levels of miR-21 were observed in both ATN and HRS vs. controls with statistically significant difference between ATN and HRS. The means were 9.466±3.21 in ATN, 2.670±1.387 in HRS and 1.090±0.586 in controls. miR-146a and miR-210 were both significantly lower in ATN and HRS compared to controls with statistically significant differences between ATN and HRS. The means of miR-210 were 1.020±0.643, 1.640±0.605 and 3.0±0.532 in ATN, HRS and controls, respectively. The means of miR-146a were 2.543±1.929, 4.98±1.353 and 6.553±0.426 in ATN, HRS and controls, respectively. ROC analyses proved that the three studied mi-RNAs can be used as differentiating biomarkers between ATN and HRS with the best performance observed with mi-21 achieving specificity and sensitivity equal 96%.

CONCLUSIONS

miR-21, miR-210 and miR-146a may be candidate differentiating markers between HRS and ATN in cirrhotic patients.

LncRNA TapSAKI promotes inflammation injury in HK-2 cells and urine derived sepsis-induced kidney injury

Objective

To explore the possible mechanism of lncRNA TapSAKI in urine derived sepsis-induced kidney injury.

Materials and methods

In vivo urine-derived sepsis (US) rat model and in vitro LPS-induced HK-2 cells were established, and TapSAKI, miR-22, PTEN, TLR4 and p-p65 expressions were detected by qRT-PCR and western blot. RNA precipitation and RNA pull-down were performed to confirm the interaction between TapSAKI and miR-22.

Results

TapSAKI was up-regulated, miR-22 was down-regulated, PTEN, TLR4 and p-p65 expressions, and inflammatory factors TNF-α and IL-6 levels were up-regulated in kidney tissue of US rats and LPS-induced HK-2 cells. In addition, TapSAKI interacted with miR-22, and negatively modulate miR-22 expression. We also observed TapSAKI promoted PTEN expression, TLR4/NF-κB pathway related proteins TLR4 and p-p65, and apoptosis protein cleaved-caspase-3 through negatively regulating miR-22. Further experiments proved TapSAKI/miR-22/TLR4/NF-κB pathway could promote HK-2 cell apoptosis. Finally, in vivo experiments showed TapSAKI knockdown negatively regulated miR-22 and positively regulate PTEN, decreased renal function indicators blood urea nitrogen and serum creatinine, and reduced TNF-α and IL-6.

Conclusion

TapSAKI was elevated in urine derived sepsis-induced kidney injury, and promoted HK-2 cell apoptosis and inflammatory response through miR-22/PTEN/TLR4/NF-κB pathway.

Argon Mitigates Impaired Wound Healing Process and Enhances Wound Healing In Vitro and In Vivo

Diabetic foot ulcers are associated with significant morbidity and mortality, and current treatments are far from optimal. Chronic wounds in diabetes are characterised by impaired angiogenesis, leukocyte function, fibroblast proliferation, and keratinocyte migration and proliferation.

Methods: We tested the effect of exposure to argon gas on endothelial cell, fibroblast, macrophage and keratinocyte cell cultures in vitro and in vivo of a streptozotocin-induced diabetic mouse model.

Results: Exposure to normobaric argon gas promotes multiple steps of the wound healing process. Argon accelerated angiogenesis, associated with upregulation of pro-angiogenic Angiopoietin-1 and vascular endothelial growth factor (VEGF) signalling in vitro and in vivo. Treatment with argon enhanced expression of transforming growth factor (TGF)-β, early recruitment of macrophages and keratinocyte proliferation. Argon had a pro-survival effect, inducing expression of cytoprotective mediators B-cell lymphoma 2 and heme oxygenase 1. Argon was able to accelerate wound closure in a diabetic mouse model.

Conclusion: Together these findings indicate that argon gas may be a promising candidate for clinical use in treatment of diabetic ulcers.

miR-21 Protects Against Ischemia/Reperfusion-Induced Acute Kidney Injury by Preventing Epithelial Cell Apoptosis and Inhibiting Dendritic Cell Maturation

Renal tubular injury and innate immune responses induced by hypoxia contribute to acute kidney injury. Accumulating evidence suggests that miR-21 overexpression protects against kidney ischemia injury. Additionally, miR-21 emerges as a key inhibitor in dendritic cell maturation. Thus, we hypothesized that miR-21 protects the kidney from IR injury by suppressing epithelial cell damage and inflammatory reaction. In this study, we investigated effects of miR-21 and its signaling pathways (PTEN/AKT/mTOR/HIF, PDCD4/NFκ-B) on kidney ischemia/reperfusion (IR) injury in vitro and in vivo. The results revealed that IR increased miR-21, HIF1α, and 2α expression in vivo and in vitro. MiR-21 interacted with HIF1α and 2α through the PTEN/AKT/mTOR pathway. Moreover, inhibition of miR-21 activated PDCD4/NFκ-B pathways, which are critical for dendritic cell maturation. Renal IR triggers local inflammation by inducing the dendritic cell maturation and promoting the secretion of IL-12, IL-6, and TNF-α cytokines. Knockdown of miR-21 intensified the effect of IR on tubular epithelial cell apoptosis and dendritic cell maturation. Our results suggested that IR-inducible miR-21 protects epithelial cells from IR injury via a feedback interaction with HIF (PTEN/AKT/mTOR/HIF/miR-21) and by inhibiting maturation of DCs through the PDCD4/NF-κB pathway. These findings highlight new therapeutic opportunities in AKI.

Neurologic and cognitive outcomes associated with the clinical use of xenon: a systematic review and meta-analysis of randomized-controlled trials

BACKGROUND

Xenon has been shown to have positive neurologic effects in various pre-clinical models. This study systematically reviewed the randomized-controlled trials (RCTs) investigating neurologic and cognitive outcomes associated with the clinical use of xenon.

METHODS

We searched PubMed, CENTRAL, EMBASE, CINAHL, elibrary.ru (for Russian studies), Google Scholar (for Russian studies), and Wanfang (for Chinese studies) for appropriate RCTs comparing neurologic or cognitive outcomes after clinical use of xenon with control treatment or with other anesthetic agents.

RESULTS

Seventeen RCTs met the inclusion criteria. Two studies investigated the effects of xenon plus therapeutic hypothermia to treat neonatal asphyxia or out-of-hospital cardiac arrest. Compared with therapeutic hypothermia alone, xenon and therapeutic hypothermia reduced cerebral white matter abnormalities after cardiac arrest but had no effect on neurocognitive outcome and mortality. Xenon had no added value when used to treat neonatal asphyxia. Thirteen RCTs compared neurocognitive effects of xenon with other anesthetic agents in surgical patients. While xenon may be associated with improved short-term (< three hours) cognitive outcome, no medium-term (six hours to three months) advantage was observed, and longer-term data are lacking. No differences in biochemical (S-100β, neuron-specific enolase) and neuropsychologic (attentional performance) outcomes were found with xenon compared with other anesthetic drugs. Finally, two studies suggest that brief, intermittent administration of sub-anesthetic doses of xenon to patients during the acute phase of substance withdrawal may improve neurocognitive outcomes.

CONCLUSIONS

Despite promising pre-clinical results, the evidence for positive clinical neurologic and cognitive outcomes associated with xenon administration is modest. Nevertheless, there is some evidence to suggest that xenon may be associated with better neurologic outcomes compared with the standard of care therapy in certain specific clinical situations. More clinical trials are needed to determine any potential benefit linked to xenon administration.

MicroRNA-30b promotes lipopolysaccharide-induced inflammatory injury and alleviates autophagy through JNK and NF-κB pathways in HK-2 cells

BACKGROUND

Acute kidney injury (AKI) is an abrupt loss of kidney function. MicroRNA-30b (miR-30b) has been reported to be involved in the inflammatory reaction of a variety of diseases. However, the role of miR-30b in AKI remains unknown. In this research, we aimed to investigate the role of miR-30b in lipopolysaccharide (LPS)-induced kindey inflammatory injury in vitro and in vivo.

METHODS

In vitro, after miR-30b mimic/inhibitor transfection and/or LPS treatment, the viability, apoptosis, autophagy and inflammatory cytokines releases, as well as activation of c-Jun-N-terminal kinase (JNK) and nuclear factor-kappa B (NF-κB) pathways were detected by cell counting kit-8 (CCK-8) assay, flow cytometry, qRT-PCR, enzyme-linked immunosorbent assay (ELISA) and western blot, respectively. In vivo, after LPS treatment and/or anti-miR-30b administration, the levels of creatinine, the activities of alanine aminotransferase (ALT) and histologic scores, as well as concentrations of inflammatory cytokines were assessed by creatinine assay kit, ALT assay kit and ELISA, respectively.

RESULTS

LPS inhibited HK-2 cell viability and induced HK-2 cell apoptosis, autophagy and the releases of inflammatory cytokines. Overexpression of miR-30b promoted LPS-induced HK-2 cell viability inhibition, cell inflammatory cytokines releases, cell apoptosis induction and activation of JNK and NF-κB signaling pathways, but inhibited LPS-induced HK-2 cell autophagy. Suppression of miR-30b had opposite effects. Moreover, suppression of miR-30b alleviated the LPS-induced kidney injury in mice model by decreasing creatinine level, ALT activity and histologic scores, as well as concentrations of inflammatory cytokines.

CONCLUSION

miR-30b participated in the LPS-induced kindey inflammatory injury in vitro and in vivo.

Role of microRNA in the detection, progression, and intervention of acute kidney injury

Acute kidney injury, characterized by sharply decreased renal function, is a common and important complication in hospitalized patients. The pathological mechanism of acute kidney injury is mainly related to immune activation and inflammation. Given the high morbidity and mortality rates of hospitalized patients with acute kidney injury, the identification of biomarkers useful for assessing risk, making an early diagnosis, evaluating the prognosis, and classifying the injury severity is urgently needed. Furthermore, investigation into the development of acute kidney injury and potential therapeutic targets is required. While microRNA was first discovered in Caenorhabditis elegans, Gary Ruvkun's laboratory identified the first microRNA target gene. Together, these two important findings confirmed the existence of a novel post-transcriptional gene regulatory mechanism. Considering that serum creatinine tests often fail in the early detection of AKI, testing for microRNAs as early diagnostic biomarkers has shown great potential. Numerous studies have identified microRNAs that can serve as biomarkers for the detection of acute kidney injury. In addition, as microRNAs can control the expression of multiple proteins through hundreds or thousands of targets influencing multiple signaling pathways, the number of studies on the functions of microRNAs in AKI progression is increasing. Here, we mainly focus on research into microRNAs as biomarkers and explorations of their functions in acute kidney injury. Impact statement Firstly, we have discussed the potential advantages and limitations of miRNA as biomarkers. Secondly, we have summarized the role of miRNA in the progress of AKI. Finally, we have made a vision of miRNA's potential and advantages as therapeutic target intervention AKI.

The microRNA miR-21 conditions the brain to protect against ischemic and traumatic injuries

Ischemic and traumatic injuries to CNS remain leading causes of death and disability worldwide, despite decades of research into risk factors, therapies, and preventative measures. Recent studies showed that CNS injuries significantly alter the cerebral microRNAome that impact the secondary brain damage as well as plasticity and recovery. Many microRNA based therapies are currently in various clinical trials for different pathologic conditions indicating their therapeutic potential. In the present review, we discuss the role of miR-21 in acute CNS injuries which is currently thought to be a potent neuroprotective microRNA. We emphasize on the potential of miR-21 in promoting cell and tissue survival and preventing inflammation and apoptosis. We also discussed the role of miR-21 in conditioning the brain to promote ischemic tolerance. Finally, we discussed some of the challenges and difficulties to develop miR-21 as a neuroprotective therapy in humans.

A Review of Anesthetic Effects on Renal Function: Potential Organ Protection

BACKGROUND

Renal protection is a critical concept for anesthesiologists, nephrologists, and urologists, since anesthesia and renal function are highly interconnected and can potentially interfere with one another. Therefore, a comprehensive understanding of anesthetic drugs and their effects on renal function remains fundamental to the success of renal surgeries, especially transplant procedures. Some experimental studies have shown that some anesthetics provide protection against renal ischemia/reperfusion (IR) injury, but there is limited clinical evidence.

SUMMARY

The effects of anesthetic drugs on renal failure are particularly important in the context of kidney transplantation, since the conditions of preservation following removal profoundly influence the recovery of organ function. Currently, preservation procedures are typically based on the usage of a cold-storage solution. Some anesthetic drugs induce anti-inflammatory, anti-necrotic, and anti-apoptotic effects. A more thorough understanding of anesthetic effects on renal function can present a novel approach for developing organ-protective strategies. The aim of this review is to discuss the effects of different anesthetic drugs on renal function, with particular focus on IR injury. Many studies have demonstrated the organ-protective effects of some anesthetic drugs, specifically propofol, which indicate the potential of some anesthetics to introduce novel organ protective targets. This is not surprising, since lipid emulsions are major components of propofol, which accumulating data show provide organ protective effects against IR injury. Key Messages: Thorough understanding of the interaction between anesthetic drugs and renal function remains fundamental to the delivery of safe perioperative care and to optimizing outcomes after renal surgeries, particularly transplant procedures. Anesthetics can be repurposed for organ protection with more information about their effects, especially during transplant procedures. Here, we review the effects of different anesthetic drugs - specifically those that contain lipids in their structure, with special reference to IR injury.

Non-coding RNA: a potential biomarker and therapeutic target for sepsis

Sepsis, a syndrome of physiologic, pathologic, and biochemical abnormalities caused by an altered systemic host response to infection, has become the main cause of death among patients admitted to the intensive care units. Recently, genome-wide expression analysis revealed that over 80% of the essential genetic elements were altered in critically ill patients. Notably, non-coding RNAs, including microRNAs, long non-coding RNAs and circular RNAs, have been proven to play essential roles in innate immunity, mitochondrial dysfunction and organ dysfunction. In this review, we introduced the biogenesis of non-coding RNAs briefly and summed up different kinds of non-coding RNAs in regulation of sepsis, which could provide a more comprehensive understanding about pathogenesis of the disease. Additionally, we summarized the limitations of current biomarkers and then recommended some non-coding RNAs as novel potential biomarkers for sepsis and sepsis-induced organ dysfunction. Besides, we also introduced some problems and challenges that need to be overcome during the clinical application of non-coding RNAs. Future research should focus on elucidating their molecular mechanisms, particularly long non-coding RNAs as well as circular RNAs and sepsis, to further understanding of the disease process. With the in-depth understanding of the mechanism of sepsis, non-coding RNAs provide a new insight into sepsis and could become the novel therapeutic targets in the future.

Role of miR‑21 on vascular endothelial cells in the protective effect of renal delayed ischemic preconditioning

Vascular endothelial cells may serve crucial roles in the development of acute kidney injury (AKI). microRNA (miR)-21, which possesses a renal protective function has been found on vascular endothelial cells. The present study aimed to test the hypothesis that miR-21 may protect vascular endothelial cells against injury, which may contribute to the protective effects of renal delayed ischemic preconditioning (IPC). Preconditioned (15 min ischemia) or Sham mice (not clamped) were subjected to 35 min occlusion of bilateral renal pedicles 4 days following preconditioning or Sham treatment. Human umbilical vein endothelial cells (HUVECs) were treated with cobalt(II) chloride (CoCl2) to establish an in vitro hypoxia model. Locked nucleic acid-modified anti-miR-21 or scrambled control oligonucleotides were transfected into cells or delivered into mice via tail vein injection <1 h prior to IPC. Following 24 h of reperfusion or hypoxia, morphological and functional parameters, apoptosis and miR-21 and programmed cell death 4 (PDCD4) expression were assessed in vivo and in vitro. Treatment of HUVECs with CoCl2 led to an upregulation of miR-21 expression, a downregulation of PDCD4 protein expression and attenuation of apoptosis. Inhibition of miR-21 expression led to increased expression levels of PDCD4 protein and apoptosis in HUVECs. IPC attenuated renal IR injury in mice. The protective effect of IPC appeared to be dependent on upregulated miR-21 expression. IPC-induced upregulation of miR-21 expression also occurred in HUVECs, and IPC also led to reduced PDCD4 expression and vascular permeability in mouse kidneys. The effects of IPC were attenuated by the inhibition of miR-21; miR-21 expression attenuated damage in vascular endothelial cells, which may contribute to the protective effects of delayed IPC on renal IR injury. The present study suggested a novel target for the prevention and repair of AKI in the future.

Acute kidney injury in the ICU: from injury to recovery: reports from the 5th Paris International Conference

The French Intensive Care Society organized its yearly Paris International Conference in intensive care on June 18-19, 2015. The main purpose of this meeting is to gather the best experts in the field in order to provide the highest quality update on a chosen topic. In 2015, the selected theme was: "Acute Renal Failure in the ICU: from injury to recovery." The conference program covered multiple aspects of renal failure, including epidemiology, diagnosis, treatment and kidney support system, prognosis and recovery together with acute renal failure in specific settings. The present report provides a summary of every presentation including the key message and references and is structured in eight sections: (a) diagnosis and evaluation, (b) old and new diagnosis tools,

Acute kidney injury in the ICU: from injury to recovery: reports from the 5th Paris International Conference

The French Intensive Care Society organized its yearly Paris International Conference in intensive care on June 18-19, 2015. The main purpose of this meeting is to gather the best experts in the field in order to provide the highest quality update on a chosen topic. In 2015, the selected theme was: "Acute Renal Failure in the ICU: from injury to recovery." The conference program covered multiple aspects of renal failure, including epidemiology, diagnosis, treatment and kidney support system, prognosis and recovery together with acute renal failure in specific settings. The present report provides a summary of every presentation including the key message and references and is structured in eight sections: (a) diagnosis and evaluation, (b) old and new diagnosis tools,

Tumor Cell-Derived Microvesicles Induced Not Epithelial-Mesenchymal Transition but Apoptosis in Human Proximal Tubular (HK-2) Cells: Implications for Renal Impairment in Multiple Myeloma

Renal impairment (RI) is one of the hallmarks of multiple myeloma (MM) and carries a poor prognosis. Microvesicles (MVs) are membrane vesicles and play an important role in disease progression. Here, we investigated the role of MVs derived from MM cells (MM-MVs) in RI of MM. We found that MM-MVs significantly inhibited viability and induced apoptosis, but not epithelial-mesenchymal transition in human kidney-2 (HK-2), a human renal tubular epithelial cell line. The protein levels of cleaved caspase-3, 8, and 9, and E-cadherin, were increased, but vementin levels were decreased in the HK-2 cells treated with MM-MVs. Through a comparative sequencing and analysis of RNA content between the MVs from RPMI8226 MM cells (RPMI8226-MVs) and K562 leukemia cells, RPMI8226-MVs were enriched with more renal-pathogenic miRNAs, in which the selective miRNAs may participate in the up-regulation of the levels of cleaved caspase-3. Furthermore, the levels of CD138+ circulating MVs (cirMVs) in the peripheral blood were positively correlated with the severity of RI in newly-diagnosed MM. Our study supports MM-MVs representing a previously undescribed factor and playing a potential role in the development of RI of MM patients, and sheds light on the potential application of CD138+ cirMV counts in precise diagnosis of RI in MM and exploring MM-MVs as a therapeutic target.

Neuroprotection and neurotoxicity in the developing brain: an update on the effects of dexmedetomidine and xenon

Growing and consistent preclinical evidence, combined with early clinical epidemiological observations, suggest potentially neurotoxic effects of commonly used anesthetic agents in the developing brain. This has prompted the FDA to issue a safety warning for all sedatives and anesthetics approved for use in children under three years of age. Recent studies have identified dexmedetomidine, the potent α2-adrenoceptor agonist, and xenon, the noble gas, as effective anesthetic adjuvants that are both less neurotoxic to the developing brain, and also possess neuroprotective properties in neonatal and other settings of acute ongoing neurologic injury. Dexmedetomidine and xenon are effective anesthetic adjuvants that appear to be less neurotoxic than other existing agents and have the potential to be neuroprotective in the neonatal and pediatric settings. Although results from recent clinical trials and case reports have indicated the neuroprotective potential of xenon and dexmedetomidine, additional randomized clinical trials corroborating these studies are necessary. By reviewing both the existing preclinical and clinical evidence on the neuroprotective effects of dexmedetomidine and xenon, we hope to provide insight into the potential clinical efficacy of these agents in the management of pediatric surgical patients.

The involvement of regulatory non-coding RNAs in sepsis: a systematic review

Background

Sepsis coincides with altered gene expression in different tissues. Accumulating evidence has suggested that microRNAs, long non-coding RNAs, and circular RNAs are important molecules involved in the crosstalk with various pathways pertinent to innate immunity, mitochondrial functions, and apoptosis.

Methods

We searched articles indexed in PubMed (MEDLINE), EMBASE and Europe PubMed Central databases using the Medical Subject Heading (MeSH) or Title/Abstract words (“microRNA”, “long non-coding RNA”, “circular RNA”, “sepsis” and/or “septic shock”) from inception to Sep 2016. Studies investigating the role of host-derived microRNA, long non-coding RNA, and circular RNA in the pathogenesis of and as biomarkers or therapeutics in sepsis were included. Data were extracted in terms of the role of non-coding RNAs in pathogenesis, and their applicability for use as biomarkers or therapeutics in sepsis. Two independent researchers assessed the quality of studies using a modified guideline from the Systematic Review Center for Laboratory animal Experimentation (SYRCLE), a tool based on the Cochrane Collaboration Risk of Bias tool.

Results

Observational studies revealed dysregulation of non-coding RNAs in septic patients. Experimental studies confirmed their crosstalk with JNK/NF-κB and other cellular pathways pertinent to innate immunity, mitochondrial function, and apoptosis. Of the included studies, the SYRCLE scores ranged from 3 to 7 (average score of 4.55). This suggests a moderate risk of bias. Of the 10 articles investigating non-coding RNAs as biomarkers, none of them included a validation cohort. Selective reporting of sensitivity, specificity, and receiver operating curve was common.

Conclusions

Although non-coding RNAs appear to be good candidates as biomarkers and therapeutics for sepsis, their differential expression across tissues complicated the process. Further investigation on organ-specific delivery of these regulatory molecules may be useful.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-016-1555-3) contains supplementary material, which is available to authorized users.

MicroRNAs in acute kidney injury

Acute kidney injury (AKI) is an important clinical issue that is associated with significant morbidity and mortality. Despite research advances over the past decades, the complex pathophysiology of AKI is not fully understood. The regulatory mechanisms underlying post-AKI repair and fibrosis have not been clarified either. Furthermore, there is no definitively effective treatment for AKI. MicroRNAs (miRNAs) are endogenous single-stranded noncoding RNAs of 19~23 nucleotides that have been shown to be crucial to the post-transcriptional regulation of various cellular biological functions, including proliferation, differentiation, metabolism, and apoptosis. In addition to being fundamental to normal development and physiology, miRNAs also play important roles in various human diseases. In AKI, some miRNAs appear to act pathogenically by promoting inflammation, apoptosis, and fibrosis, while others may act protectively by exerting anti-inflammatory, anti-apoptotic, anti-fibrotic, and pro-angiogenic effects. Thus, miRNAs have not only emerged as novel biomarkers for AKI; they also hold promise to be potential therapeutic targets.

Preclinical neuroprotective actions of xenon and possible implications for human therapeutics: a narrative review

PURPOSE

The purpose of this report is to facilitate an understanding of the possible application of xenon for neuroprotection in critical care settings. This narrative review appraises the literature assessing the efficacy and safety of xenon in preclinical models of acute ongoing neurologic injury.

SOURCE

Databases of the published literature (MEDLINE® and EMBASE™) were appraised for peer-reviewed manuscripts addressing the use of xenon in both preclinical models and disease states of acute ongoing neurologic injury. For randomized clinical trials not yet reported, the investigators' declarations in the National Institutes of Health clinical trials website were considered.

PRINCIPAL FINDINGS

While not a primary focus of this review, to date, xenon cannot be distinguished as superior for surgical anesthesia over existing alternatives in adults. Nevertheless, studies in a variety of preclinical disease models from multiple laboratories have consistently shown xenon's neuroprotective properties. These properties are enhanced in settings where xenon is combined with hypothermia. Small randomized clinical trials are underway to explore xenon's efficacy and safety in clinical settings of acute neurologic injury where hypothermia is the current standard of care.

CONCLUSION

According to the evidence to date, the neuroprotective efficacy of xenon in preclinical models and its safety in clinical anesthesia set the stage for the launch of randomized clinical trials to determine whether these encouraging neuroprotective findings can be translated into clinical utility.

Anti-inflammatory effects of miR-21 in the macrophage response to peritonitis

We investigated the role of microRNA-21 in the macrophage response to peritonitis; microRNA-21 expression increases in peritoneal macrophages after lipopolysaccharide stimulation but is delayed until 48 hours after cecal ligation and puncture. MicroRNA-21-null mice and bone marrow-derived cell lines were exposed to cecal ligation and puncture or lipopolysaccharide, and survival, microRNA-21 levels, target messenger RNAs and proteins, and cytokines were assayed. Macrophages were also transfected with microRNA-21 mimics and antagomirs, and similar endpoints were measured. Survival in microRNA-21-null mice was significantly decreased after lipopolysaccharide-induced peritonitis but unchanged after cecal ligation and puncture compared with similarly treated wild-type mice. MicroRNA-21 expression, tumor necrosis factor-α, interleukin 6, and programmed cell death protein 4 levels were increased after lipopolysaccharide addition in peritoneal cells. Pelino1 and sprouty (SPRY) messenger RNAs were similarly increased early, whereas programmed cell death protein 4 messenger RNA was decreased after lipopolysaccharide, and all microR-21 target messenger RNAs were subsequently decreased by 24 hours after lipopolysaccharide. Transfection with mimics and antagomirs led to appropriate responses in microRNA-21 and tumor necrosis factor-α. Knockdown of microRNA-21 in bone marrow-derived cells showed increased tumor necrosis factor-α and decreased interleukin 10 in response to lipopolysaccharide. Target proteins were unaffected by knockdown as was extracellular signal-regulated kinase; however, the nuclear factor κB p65 subunit was increased after lipopolysaccharide in the microRNA-21 knockout cells. In contrast, there was little change in these parameters after cecal ligation and puncture induction between null and wild-type mice. MicroRNA-21 is beneficial to survival in mice following lipopolysaccharide peritonitis. Overexpression of microRNA-21 decreased tumor necrosis factor-α secretion, whereas suppression of microRNA-21 expression increased tumor necrosis factor-α and interleukin 6, and decreased interleukin 10 levels after lipopolysaccharide. Protein targets of microRNA-21 were not different following suppression of microRNA-21. Nuclear factor κB was increased by suppression of microRNA-21. These findings demonstrate microRNA-21 is beneficial in modulating the macrophage response to lipopolysaccharide peritonitis and an improved understanding of the anti-inflammatory effects of microRNA-21 may result in novel, targeted therapy against peritonitis and sepsis.