Non-coding RNA-Associated ceRNA Networks in a New Contrast-Induced Acute Kidney Injury Rat Model

LncRNA HILPDA promotes contrast-induced acute kidney injury by recruiting eIF4B to upregulate XPO1 expression

Background

Contrast-induced acute kidney injury (CI-AKI) is a serious and common complication following the use of iodinated contrast media, with a 20% fatality rate. The function of long non-coding RNA HILPDA (lnc-HILPDA) in CI-AKI development was investigated in this study.

Methods

CI-AKI models were constructed by iopromide treatment. Kidney pathological changes were analyzed by HE staining. TUNEL labeling and flow cytometry were used to examine cell apoptosis. CCK-8 assay was used to determine cell viability. The interactions between lnc-HILPDA, eIF4B, and XPO1 were verified by RIP or Co-IP assay.

Results

Lnc-HILPDA was upregulated in CI-AKI, and its knockdown decreased contrast-trigged oxidative stress and apoptosis in HK-2 cells. Mechanically, lnc-HILPDA activated the NF-κB pathway by upregulating XPO1 through interacting with eIF4B. Moreover, the inhibitory effect of lnc-HILPDA downregulation on contrast-induced oxidative stress and apoptosis in HK-2 cells was weakened by XPO1 overexpression.

Conclusion

Lnc-HILPDA accelerated CI-AKI progression by elevating XPO1 expression through eIF4B to activate NF-κB pathway.

A systematic review of epigenetic interplay in kidney diseases: Crosstalk between long noncoding RNAs and methylation, acetylation of chromatin and histone

The intricate crosstalk between long noncoding RNAs (lncRNAs) and epigenetic modifications such as chromatin/histone methylation and acetylation offer new perspectives on the pathogenesis and treatment of kidney diseases. lncRNAs, a class of transcripts longer than 200 nucleotides with no protein-coding potential, are now recognized as key regulatory molecules influencing gene expression through diverse mechanisms. They modulate the epigenetic modifications by recruiting or blocking enzymes responsible for adding or removing methyl or acetyl groups, such as DNA, N6-methyladenosine (m6A) and histone methylation and acetylation, subsequently altering chromatin structure and accessibility. In kidney diseases such as acute kidney injury (AKI), chronic kidney disease (CKD), diabetic nephropathy (DN), glomerulonephritis (GN), and renal cell carcinoma (RCC), aberrant patterns of DNA/RNA/histone methylation and acetylation have been associated with disease onset and progression, revealing a complex interplay with lncRNA dynamics. Recent studies have highlighted how lncRNAs can impact renal pathology by affecting the expression and function of key genes involved in cell cycle control, fibrosis, and inflammatory responses. This review will separately address the roles of lncRNAs and epigenetic modifications in renal diseases, with a particular emphasis on elucidating the bidirectional regulatory effects and underlying mechanisms of lncRNAs in conjunction with DNA/RNA/histone methylation and acetylation, in addition to the potential exacerbating or renoprotective effects in renal pathologies. Understanding the reciprocal relationships between lncRNAs and epigenetic modifications will not only shed light on the molecular underpinnings of renal pathologies but also present new avenues for therapeutic interventions and biomarker development, advancing precision medicine in nephrology.

CIRCVMA21-RELATED PATHWAY ALLEVIATES LIPOPOLYSACCHARIDE-INDUCED HK-2 CELL INJURY

ABSTRACT

Background : It is reported that circVMA21 has an inhibition effect on sepsis-induced acute kidney injury (AKI). Therefore, the underlying molecular mechanisms of circVMA21 in AKI are worthy of further investigation. Material and Methods : Lipopolysaccharide (LPS) was used to induce HK2 cell injury. CircVMA21, miR-337-3p and ZEB2 expression was tested by qRT-PCR. Cell growth was detected by CCK8 assay, EdU assay, and flow cytometry. Protein levels were examined by western blot. The levels of inflammatory factors and oxidative stress markers were measured to evaluate cell inflammatory response and oxidative stress. RNA relationship as verified by dual-luciferase reporter assay, RIP assay, and RNA pull-down assay. Results : CircVMA21 had decreased expression in AKI patients. Overexpressed circVMA21 alleviated LPS-induced HK2 cell inflammation, apoptosis, and oxidative stress. Moreover, circVMA21 sponged miR-337-3p, and miR-337-3p targeted ZEB2. The inhibitory effect of circVMA21 on LPS-induced HK2 cell injury was reversed by miR-337-3p overexpression, and ZEB2 overexpression abolished the promotion effect of miR-337-3p on LPS-induced HK2 cell injury. Conclusions : CircVMA21 could inhibit LPS-induced HK2 cell injury via miR-337-3p/ZEB2 axis.

Potential therapeutic applications of circular RNA in acute kidney injury

Acute kidney injury (AKI) is a common clinical syndrome characterized by a rapid deterioration in renal function, manifested by a significant increase in creatinine and a sharp decrease in urine output. The incidence of morbidity and mortality associated with AKI is on the rise, with most patients progressing to chronic kidney disease or end-stage renal disease. Treatment options for patients with AKI remain limited. Circular RNA (circRNA) is a wide and diverse class of non-coding RNAs that are present in a variety of organisms and are involved in gene expression regulation. Studies have shown that circRNA acts as a competing RNA, is involved in disease occurrence and development, and has potential as a disease diagnostic and prognostic marker. CircRNA is involved in the regulation of important biological processes, including apoptosis, oxidative stress, and inflammation. This study reviews the current status and progress of circRNA research in the context of AKI.

LncRNA 152 attenuates lipopolysaccharide-induced acute kidney injury in rats by regulating the FGF23/Klotho/MAPK axis

AIM

This study aimed to explore the effect and related mechanisms of LncRNA 152 in acute kidney injury (AKI).

METHODS

QRT-PCR was used to detect the expression of LncRNA 152, FGF23 and Klotho in the serum of patients with AKI. Subsequently, Sprague Dawley (SD) rats were induced into AKI animal model by lipopolysaccharide (LPS). Then, H&E staining was performed to observe the pathological changes in the rat kidney tissues; qRT-PCR to detect the expression of LncRNA 152, FGF23 and Klotho in the rat kidney tissues; biochemical assay and ELISA to assess the levels of renal function indexes and inflammatory factors in rat serum, as well as oxidative stress indexes in kidney tissues; and western blot to measure the protein expressions of FGF23, Klotho, p-p38 and p38 in rat kidney tissues.

RESULTS

LncRNA 152 was significantly down-regulated in serum of AKI patients and kidney tissues of AKI rats. In AKI patients, LncRNA 152 was negatively correlated with FGF23 expression while positively correlated with Klotho expression. LncRNA 152 overexpression reduced the levels of blood urea nitrogen (BUN), creatinine (Cr) and cystatin C (Cys-C) and inflammatory factors in serum of AKI rats and attenuated pathological damage and oxidative stress of kidney tissues. In addition, LncRNA 152 overexpression also decreased FGF23 expression and p-p38/p38 ratio while up-regulated Klotho expression in the kidney tissues of AKI rats.

CONCLUSION

LncRNA 152 attenuates oxidative stress and inflammatory responses by regulating the FGF23/Klotho axis and inhibiting the MAPK signalling pathway in rat kidney tissues, thereby ameliorating LPS-induced AKI.

Apelin-13 alleviates contrast-induced acute kidney injury by inhibiting endoplasmic reticulum stress

Contrast-induced acute kidney injury (CI-AKI) is a severe complication associated with significant morbidity and mortality, and effective therapeutic strategies are still lacking. Apelin is an endogenous physiological regulator with antioxidative, anti-inflammatory and antiapoptotic properties. However, the role of apelin-13 in CI-AKI remains unclear. In our study, we found that the protein expression levels of apelin were significantly downregulated in rat kidney tissues and HK-2 cells during contrast media treatment. Moreover, we explored the protective effect of apelin-13 on renal tubule damage using in vitro and in vivo models of CI-AKI. Exogenous apelin-13 ameliorated endoplasmic reticulum stress, reactive oxygen species and apoptosis protein expression in contrast media-treated cells and rat kidney tissues. Mechanistically, the downregulation of endoplasmic reticulum stress contributed critically to the antiapoptotic effect of apelin-13. Collectively, our findings reveal the inherent mechanisms by which apelin-13 regulates CI-AKI and provide a prospective target for the prevention of CI-AKI.

Combination of PARP inhibitor and CDK4/6 inhibitor modulates cGAS/STING-dependent therapy-induced senescence and provides "one-two punch" opportunity with anti-PD-L1 therapy in colorectal cancer

Although PARP inhibitor (PARPi) has been proven to be a promising anticancer drug in cancer patients harboring BRCA1/2 mutation, it provides limited clinical benefit in colorectal cancer patients with a low prevalence of BRCA1/2 mutations. In our study, we found PARPi talazoparib significantly induced cellular senescence via inhibiting p53 ubiquitination and activating p21. Furthermore, CDK4/6i palbociclib amplified this therapy-induced senescence (TIS) in vitro and in vivo. Mechanistically, talazoparib and palbociclib combination induced senescence-associated secretory phenotype (SASP), and characterization of SASP components revealed type I interferon (IFN)-related mediators, which were amplified by cGAS/STING signaling. More importantly, RNA sequencing data indicated that combination therapy activated T cell signatures and combination treatment transformed the tumor microenvironment (TME) into a more antitumor state with increased CD8 T cells and natural killer (NK) cells and decreased macrophages and granulocytic myeloid-derived suppressor cells (G-MDSCs). Moreover, clearance of the TIS cells by αPD-L1 promoted survival in immunocompetent mouse colorectal cancer models. Collectively, we elucidated the synergistic antitumor and immunomodulatory mechanisms of the talazoparib-palbociclib combination. Further combination with PD-L1 antibody might be a promising "one-two punch" therapeutic strategy for colorectal cancer patients.

Identification of lncRNA-miRNA-mRNA ceRNA network as biomarkers for acute kidney injury

OBJECTIVE

Acute kidney injury (AKI) is a global problem due to its high morbidity and mortality. The aim of this study was to identify the key RNAs involved in the ischemia/reperfusion (I/R) or cisplatin (CIS) induced AKI.

METHODS

Gene Expression Omnibus database was used to download the microarray dataset GSE106993, GSE130814 and GSE98622. Differentially expressed lncRNAs (DE-lncRNAs) and DE-mRNAs were identified in I/R and CIS induced AKI. The target miRNAs of DE lncRNAs were predicted from miRDB, and the miRNA of lncRNA target mRNAs were predicted form StarBase dataset. The ceRNA regulatory networks, GO and KEGG enrichment analysis, and protein-protein interaction (PPI) of I/R and CIS induced AKI specific genes were constructed. The CIBESORT was applied to infer the proportion of 22 immune infiltration cells based on gene expression profiles of I/R and CIS induced AKI.

RESULTS

Totally, 2 DE-lncRNAs and 375 DE-mRNAs were identified in I/R and CIS induced AKI. The common ceRNA network was constructed between CIS group and I/R induced AKI group, which contained 2 lncRNAs (Platr7 and Gm15611), 65 mmu-miRNAs and 167 mRNAs. The 167 common mRNAs were enriched in the biological process of transcription regulation, metabolic process, cell proliferation, the cellular component (CC) of extracellular region and space, the molecular function of DNA binding, and transcription regulator activity in CIS and IRI induced AKI. The common 167 mRNAs involved in the MAPK signaling pathway and JAK-STAT signaling pathway were identified. Protein-Protein Interaction (PPI) Network of ceRNAs network expressed gene was constructed, including 81 nodes, which contained 3 upregulated genes and 78 downregulated genes. Among them, mitochondrial apoptosis-related genes Pmaip1 and Nptx1 showed significantly high expression in the GSE98622 and GSE106993 data sets. The investigation to the connection between the gene expression profiles and immune cell infiltration showed considerable differences in immune cell percentage between AKI group and normal group.

CONCLUSION

Novel lncRNAs and mRNAs were identified, which may serve as potential biomarkers to predict the diagnostic and therapeutic targets for AKI patients based on a large-scale sample. More importantly, the ceRNA network of I/R or CIS induced AKI was constructed, which provides valuable information to further explore the molecular mechanism underlying onset and progression of AKI.

A protein encoded by circular ZNF609 RNA induces acute kidney injury by activating the AKT/mTOR-autophagy pathway

Autophagy plays a crucial role in the development and progression of ischemic acute kidney injury (AKI). However, the function and mechanism of circular RNAs (circRNAs) in the regulation of autophagy in ischemic AKI remain unexplored. Herein, we find that circ-ZNF609, originating from the ZNF609 locus, is highly expressed in the kidney after ischemia/reperfusion injury, and urinary circ-ZNF609 is a moderate predictor for AKI in heart disease patients. Overexpression of circ-ZNF609 can activate AKT3/mTOR signaling and induce autophagy flux impairment and cell apoptosis while inhibiting proliferation in HK-2 cells, which is blocked by silencing circ-ZNF609. Mechanistically, circ-ZNF609 encodes a functional protein consisting of 250 amino acids (aa), termed ZNF609-250aa, the overexpression of which can activate AKT3/mTOR signaling and induce autophagy flux impairment and cell apoptosis in HK-2 cells in vitro and in AKI kidneys in vivo. The blockade of AKT and mTOR signaling with pharmacological inhibitors is capable of reversing ZNF609-250aa-induced autophagy flux impairment and cell apoptosis in HK-2 cells. The present study demonstrates that highly expressed circ-ZNF609-encoded ZNF609-250aa induces cell apoptosis and AKI by impairing the autophagy flux via an AKT/mTOR-dependent mechanism. These findings imply that targeting circ-ZNF609 may be a novel therapy for ischemic AKI.

LncRNA HOTTIP promotes inflammatory response in acute gouty arthritis via miR-101-3p/BRD4 axis

INTRODUCTION

Acute gouty arthritis (AGA) is characterized by the accumulation of pro-inflammatory factors. This research aimed to examine the regulation of long non-coding RNA HOXA distal transcript antisense RNA (HOTTIP) in AGA on inflammation and its potential mechanisms.

METHODS

Serum levels of HOTTIP in AGA patients were examined by reverse-transcription quantitative polymerase chain reaction. The receiver operating characteristic curve was performed in the diagnosis of AGA patients. Monosodium urate (MSU) stimulation of THP-1-derived macrophages was used to establish an in vitro AGA model. Enzyme-linked immunosorbent assay was carried out to assess the levels of pro-inflammatory cytokines. Pearson correlation was applied to examine the correlation. RNA immunoprecipitation assay and dual-luciferase reporter assay were employed to identify the targeting relationship between miR-101-3p and HOTTIP or bromodomain-containing 4 (BRD4).

RESULTS

HOTTIP and BRD4 were statistically overexpressed in AGA patients compared with controls, while miR-101-3p was reduced (P < 0.05). Serum HOTTIP can significantly distinguish AGA patients from healthy controls. HOTTIP bound with miR-101-3p then augmented BRD4 via a competing endogenous RNA mechanism. Additionally, HOTTIP levels were elevated in a dose-dependent manner by MSU (P < 0.05). Weakened HOTTIP significantly inhibited MSU-induced release of pro-inflammatory factors interleukin (IL)-1β, IL-8, and transforming growth factor-α in macrophages (P < 0.05), but this inhibition was reversed by silencing miR-101-3p (P < 0.05).

CONCLUSION

In short, HOTTIP contributes to inflammation via miR-101-3p/BRD4 axis, and serves as a new diagnostic biomarker. This study offers a renewed perspective on the diagnosis and treatment of AGA.

Contrast-induced acute kidney injury and its contemporary prevention

The complexity and application range of interventional and diagnostic procedures using contrast media (CM) have recently increased. This allows more patients to undergo procedures that involve CM administration. However, the intrinsic CM toxicity leads to the risk of contrast-induced acute kidney injury (CI-AKI). At present, effective therapy of CI-AKI is rather limited. Effective prevention of CI-AKI therefore becomes crucially important. This review presents an in-depth discussion of CI-AKI incidence, pathogenesis, risk prediction, current preventive strategies, and novel treatment possibilities. The review also discusses the difference between CI-AKI incidence following intraarterial and intravenous CM administration. Factors contributing to the development of CI-AKI are considered in conjunction with the mechanism of acute kidney damage. The need for ultimate risk estimation and the prediction of CI-AKI is stressed. Possibilities of CI-AKI prevention is evaluated within the spectrum of existing preventive measures aimed at reducing kidney injury. In particular, the review discusses intravenous hydration regimes and pre-treatment with statins and N-acetylcysteine. The review further focuses on emerging alternative imaging technologies, alternative intravascular diagnostic and interventional procedures, and new methods for intravenous hydration guidance; it discusses the applicability of those techniques in complex procedures and their feasibility in current practise. We put emphasis on contemporary interventional cardiology imaging methods, with a brief discussion of CI-AKI in non-vascular and non-cardiologic imaging and interventional studies.

Regulation Networks of Non-Coding RNA-Associated ceRNAs in Cisplatin-Induced Acute Kidney Injury

Cisplatin is widely used as a chemotherapeutic drug to treat various solid tumors. However, it often induces severe side effects, including nephrotoxicity, which limits its application in clinical settings. Furthermore, the underlying mechanisms of action are unclear. Here, we applied whole-transcriptome RNA sequencing to a cisplatin-induced acute kidney injury (CP-AKI) mouse model to evaluate competing endogenous RNA (ceRNA) networks. We found 4460 mRNAs, 1851 long non-coding RNAs, 101 circular RNAs, and 102 microRNAs significantly differentially expressed between CP-AKI and control mice. We performed gene set enrichment analysis to reveal the biological functions of the mRNAs and constructed non-coding RNA-associated ceRNA networks in CP-AKI mice. Two ceRNA regulatory pathways, Lhx1os-203/mmu-miR-21a-3p/Slc7a13 and circular RNA_3907/mmu-miR-185-3p/Ptprn, were validated using quantitative real-time PCR. The protein–protein interaction network indicated that Il6, Cxcl1, Cxcl2, and Plk1 serve as hub genes and are highly connected with the inflammatory response or DNA damage. Transcription factors, such as Stat3, Cebpb, and Foxm1, regulate gene expression levels in CP-AKI. Our study provides insight into non-coding RNA-associated ceRNA networks and mRNAs in CP-AKI and identifies potential treatment targets.

Silencing circ_0074371 inhibits the progression of sepsis-induced acute kidney injury by regulating miR-330-5p/ELK1 axis

BACKGROUND

Sepsis-induced acute kidney injury (AKI) is a common in clinic. Circular RNAs (circRNAs) play significant roles in ameliorating AKI. The purpose of this study was aimed to identify the role of circ_0074371 and the potential action mechanism in sepsis-induced AKI.

METHODS

AKI patients and healthy individual serum samples were collected and the relative expression of circ_0074371 was measured by real-time polymerase chain reaction (RT-PCR). HK2 cells were treated with different dose (0, 2.5, 5 and 10 μg/ml) lipopolysaccharide (LPS) to establish the AKI cell model. The cell viability and apoptosis of HK2 cells were detected using cell counting kit-8 (CCK-8) and flow cytometry, respectively. The contents of malondialdehyde (MDA), and superoxide dismutase (SOD) were evaluated using the relative commercial kits. The IL-1β and TNF-α levels in cell culture supernatants were measured by ELISA. The interaction relationship between miR-330-5p and circ_0074371 or ELK1 was predicted by Targetscan database and further confirmed by the dual-luciferase reporter assay system.

RESULTS

The circ_0074371 expression was up-regulated in sepsis patients and LPS-induced HK2 cells. Silencing circ_0074371 promoted HK2 cells viability and inhibited the HK2 cells apoptosis. miR-330-5p inhibitor weakened circ_0074371 inhibitor-induced cell viability, apoptosis and oxidative stress. Further mechanism analysis showed that circ_0074371 acted as a sponge for miR-330-5p to increase ELK1 expression level. Importantly, miR-330-5p downregulation or ELK1 upregulation reversed the action of circ_0074371 knockdown on LPS-induced HK2 cells.

CONCLUSION

Knockdown of circ_0074371 ameliorated LPS-induced HK2 cells apoptosis, inflammation and oxidative stress via regulating miR-330-5p/ELK1, opening a new window into the pathogenesis AKI.

Circular RNAs in Acute Kidney Injury: Roles in Pathophysiology and Implications for Clinical Management

Acute kidney injury (AKI) is a common clinical condition, results in patient morbidity and mortality, and incurs considerable health care costs. Sepsis, ischaemia-reperfusion injury (IRI) and drug nephrotoxicity are the leading causes. Mounting evidence suggests that perturbations in circular RNAs (circRNAs) are observed in AKI of various aetiologies, and have pathogenic significance. Aberrant circRNA expressions can cause altered intracellular signalling, exaggerated oxidative stress, increased cellular apoptosis, excess inflammation, and tissue injury in AKI due to sepsis or IRI. While circRNAs are dysregulated in drug-induced AKI, their roles in pathogenesis are less well-characterised. CircRNAs also show potential for clinical application in diagnosis, prognostication, monitoring, and treatment. Prospective observational studies are needed to investigate the role of circRNAs in the clinical management of AKI, with special focus on the safety of therapeutic interventions targeting circRNAs and the avoidance of untoward off-target effects.

Icariin and Competing Endogenous RNA Network: A Potential Protective Strategy Against Contrast-Induced Acute Kidney Injury

Background

Icariin presents protective effect in several kidney diseases. However, the role of icariin in contrast-induced acute kidney injury (CIAKI) is still unclear. This study aimed to investigate the effect of icariin in CIAKI, as well as exploring the underlying mechanism from the aspect of interaction between protein-coding genes and non-coding RNAs.

Methods

The effect of icariin was evaluated in both in vivo and in vitro CIAKI models. Rat kidneys were collected for genome-wide sequencing. The differentially expressed genes (DEGs) were screened and visualized by R software. The function annotation of DEGs was analyzed by Metascape. By Cytoscape software, the competing endogenous RNA (ceRNA) network was constructed, and hub genes were selected. Expressions of hub genes were validated by PCR. Association of hub genes in the ceRNA network and renal function was also examined.

Results

Icariin protected against CIAKI in both in vivo and in vitro models. Based on DEGs in icariin pretreated CIAKI rats, lncRNA- and circRNA-associated ceRNA networks were constructed, respectively. Function annotation showed the ceRNA networks were enriched in ERK1 and ERK2 cascade, MAPK signaling and NF-κB signaling. Further, two circRNAs, six lncRNAs, four miRNAs and nine mRNAs were selected as hub genes of the ceRNA network. Among them, eight mRNAs (Acot1, Cbwd1, Ly6i, Map3k14, Mettl2b, Nyap1, Set and Utp20) were negatively correlated with renal function, while one mRNA (Tmem44) was positively correlated with renal function.

Conclusion

Icariin presented a protective effect against CIAKI. The ceRNA network, involving Acot1, Cbwd1, Ly6i, Map3k14, Mettl2, Nyap1, Set, Tmem44 and Utp20, might partially contribute to the underlying mechanism of icariin protection by regulation of ERK1 and ERK2 cascade, MAPK signaling and NF-κB signaling.

The Intersection of Acute Kidney Injury and Non-Coding RNAs: Inflammation

Acute renal injury (AKI) is a complex clinical syndrome, involving a series of pathophysiological processes, in which inflammation plays a key role. Identification and verification of gene signatures associated with inflammatory onset and progression are imperative for understanding the molecular mechanisms involved in AKI pathogenesis. Non-coding RNAs (ncRNAs), involved in epigenetic modifications of inflammatory responses, are associated with the aberrant expression of inflammation-related genes in AKI. However, its regulatory role in gene expression involves precise transcriptional regulation mechanisms which have not been fully elucidated in the complex and volatile inflammatory response of AKI. In this study, we systematically review current research on the intrinsic molecular mechanisms of ncRNAs that regulate the inflammatory response in AKI. We aim to provide potential research directions and strategies for developing ncRNA-targeted gene therapies as an intervention for the inflammatory damage in AKI.

Noncoding RNA-Associated Competing Endogenous RNA Networks in Doxorubicin-Induced Cardiotoxicity

Accumulating evidence has indicated that noncoding RNAs (ncRNAs) are involved in doxorubicin-induced cardiotoxicity (DIC). However, the ncRNA-associated competing endogenous RNA (ceRNA)-mediated regulatory mechanisms in DIC remain unclear. In this study, we aimed to systematically investigate the alterations in expression levels of long noncoding RNA (lncRNA), circular RNA (circRNA), microRNA (miRNA), and mRNA in a DIC mouse model through deep RNA sequencing (RNA-seq). The results showed that 217 lncRNAs, 41 circRNAs, 11 miRNAs and 3633 mRNAs were aberrantly expressed. Moreover, the expression of 12 randomly selected transcripts was determined by real-time quantitative polymerase chain reaction to test the reliability of RNA-seq data. Based on the interaction between miRNAs and mRNAs, as well as lncRNAs/circRNAs and miRNAs, we constructed comprehensive lncRNA or circRNA-associated ceRNA networks in DIC mice. Moreover, we performed Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses for differentially expressed genes. In conclusion, these identified ceRNA interactions provide new insight into the underlying mechanism and may be crucial therapeutic targets of DIC.

Inhibition of Circ-Snrk ameliorates apoptosis and inflammation in acute kidney injury by regulating the MAPK pathway

Background

Circular RNA (circRNA) is involved in the process of acute kidney injury (AKI), but only a few circRNAs have been reported. In the study, we investigated a new circRNA and its association with AKI.

Methods

An AKI model was established in Sprague-Dawley rats, followed by serum creatinine and urea nitrogen tests measured by a biochemical analyzer. The pathological changes and apoptosis in the renal tissue were detected by Hematoxylin and Eosin, and TUNEL staining. Then, circRNA expression in AKI was determined by quantitative real-time-PCR (qRT-PCR). NRK-52E cells were induced with hypoxia/reoxygenation (H/R) as in vitro models and the circ-Snrk level was tested by qRT-PCR. The effects of circ-Snrk in H/R-induced NRK-52E cells were assessed by flow cytometry, western blot, and enzyme-linked immunosorbent assay. Finally, RNA sequencing and western blot analysis were used to validate the mRNA profile and pathways involved in circ-Snrk knockdown in H/R-induced NRK-52E.

Results

A reliable AKI rat model and H/R cell model were established. qRT-PCR demonstrated that circ-Snrk level was upregulated in AKI left kidney tissue and NRK-52E cells with H/R treatment. Circ-Snrk knockdown inhibited apoptosis of NRK-52E cells and secretion of inflammatory factors (IL-6 and TNF-α). RNA sequencing showed that the mRNA profile changed after inhibition of circ-Snrk and differential expression of mRNA mainly enriched various signaling pathways, including MAPK signaling pathway. Furthermore, western blot indicated that circ-Snrk knockdown could inhibit the activation of p-JNK and p-38 transcription factors.

Conclusions

Circ-Snrk is involved in AKI development and associated with the MAPK signaling pathway in AKI.

An Update of Long-Noncoding RNAs in Acute Kidney Injury

Acute kidney injury (AKI) is a global public health concern with high morbidity, mortality, and medical costs. Despite advances in medicine, effective therapeutic regimens for AKI remain limited. Long non-coding RNAs (lncRNAs) are a subtype of non-coding RNAs, which longer than 200 nucleotides and perform extremely diverse functions in biological processes. Recently, lncRNAs have emerged as promising biomarkers and key mediators to AKI. Meanwhile, existing research reveals that the aberrant expression of lncRNAs has been linked to major pathological processes in AKI, including the inflammatory response, cell proliferation, and apoptosis, via forming the lncRNA/microRNA/target gene regulatory axis. Following a comprehensive and systematic search of the available literature, 87 relevant papers spanning the years 2005 to 2021 were identified. This review aims to provide and update an overview of lncRNAs in AKI, and further shed light on their potential utility as AKI biomarkers and therapeutic targets.

Construction and Analysis of Immune Infiltration-Related ceRNA Network for Kidney Stones

Purpose: Kidney stones is a common medical issue that mediates kidney injury and even kidney function loss. However, the exact pathogenesis still remains unclear. This study aimed to explore the potential competing endogenous RNA (ceRNA)-related pathogenesis of kidney stones and identify the corresponding immune infiltration signature. Methods: One mRNA and one long non-coding RNA (lncRNA) microarray dataset was obtained from the GEO database. Subsequently, we compared differentially expressed mRNAs (DE-mRNAs) and lncRNAs between Randall's plaques in patients with calcium oxalate (CaOx) stones and controls with normal papillary tissues. lncRNA-targeted miRNAs and miRNA-mRNA pairs were predicted using the online databases. lncRNA-related DE-mRNAs were identified using the Venn method, and GO and KEGG enrichment analyses were subsequently performed. The immune-related lncRNA-miRNA-mRNA ceRNA network was developed. The CIBERSORT algorithm was used to estimate the rate of immune cell infiltration in Randall's plaques. The ceRNA network and immune infiltration were validated in the glyoxylate-induced hyperoxaluric mouse model and oxalate-treated HK-2 cells. Results: We identified 2,340 DE-mRNAs and 929 DE-lncRNAs between Randall's plaques in patients with CaOx stones and controls with normal papillary tissues. lncRNA-related DE-mRNAs were significantly enriched in extracellular matrix organization and collagen-containing extracellular matrix, which were associated with kidney interstitial fibrosis. The immune-related ceRNA network included 10 lncRNAs, 23 miRNAs, and 20 mRNAs. Moreover, we found that M2 macrophages and resting mast cells were differentially expressed between Randall's plaques and normal tissues. Throughout kidney stone development, kidney tubular injury, crystal deposition, collagen fiber deposition, TGF-β expression, infiltration of M1 macrophages, and activation of mast cells were more frequent in glyoxylate-induced hyperoxaluric mice compared with control mice. Nevertheless, M2 macrophage infiltration increased in early stages (day 6) and decreased as kidney stones progressed (day 12). Furthermore, treatment with 0.25 and 0.5 mM of oxalate for 48 h significantly upregulated NEAT1, PVT1, CCL7, and ROBO2 expression levels and downregulated hsa-miR-23b-3p, hsa-miR-429, and hsa-miR-139-5p expression levels in the HK-2 cell line in a dose-dependent manner. Conclusion: We found that significant expressions of ceRNAs (NEAT1, PVT1, hsa-miR-23b-3p, hsa-miR-429, hsa-miR-139-5p, CCL7, and ROBO2) and infiltrating immune cells (macrophages and mast cells) may be involved in kidney stone pathogenesis. These findings provide novel potential therapeutic targets for kidney stones.

Construction of ceRNA Network to Reveal Potential Biomarkers in Crohn's Disease and Validation in a TNBS Induced Mice Model

Purpose

We aimed to construct a competing endogenous RNA (ceRNA) network and explore the potential biomarkers in Crohn's disease (CD) via bioinformatics analysis. Validation of candidate biomarkers in a 2,4,6-trinitrobenzene sulfonic acid (TNBS) induced experimental colitis model and ceRNA network in an HCT116 cell line was also an aim, along with purposing to reveal the pathogenesis of CD.

Methods

GSE102134 and GSE67106 datasets were obtained and used to screen the differentially expressed genes. WCGNA was applied to identify the relative model to construct the ceRNA network. Furthermore, the relationship between candidate gene and immune infiltration was investigated. Then, the expression of potential biomarkers was validated via qRT-PCR in a TNBS induced experimental colitis model. Finally, the ceRNA network was confirmed by RNAi experiments in an HCT116 cell line.

Results

The ceRNA network, consisting of four lncRNAs, four miRNAs, and eight mRNAs, was constructed and the ROC analysis showed four mRNAs (PTGS2, LPL, STAT1, and TRIB2) had high diagnostic accuracy (AUC>0.9). In addition, upregulated PTGS2 was positively correlated with immune cell infiltration, including Natural killer cells, exhausted T-cells, monocytes, and Dendritic cells. The outcome of this TNBS induced experimental colitis model verified that the expression of PTGS2 and mir-429 was consistent with results of previous bioinformatics analysis. Furthermore, the predicted ceRNA network MIR3142HG/mir-429/PTGS2 were validated via RNA interference. Knockout of MIR3142HG decreased the mRNA level of PTGS2, whereas inhibition of mir-429 increased the mRNA level of PTGS2 in the HCT116 cell line.

Conclusion

The exploration of the ceRNA network in this work might contribute to understanding the pathogenesis of CD. The constructed MIR3142HG/mir-429/PTGS2 ceRNA network may play a role in CD, and PTGS2 can be a potential immune-related biomarker in CD.

Comprehensive analysis of the long non-coding RNA expression profile and functional roles in a contrast-induced acute kidney injury rat model

Long non-coding RNAs (lncRNAs) have been identified as a class of regulatory RNAs that participate in both physiological and pathological conditions, including acute kidney injury. However, the roles of lncRNA dysregulation in the pathogenesis of contrast-induced acute kidney injury (CI-AKI) are largely unknown. In the present study, the expression profiles of lncRNAs in kidney tissue were compared between rats with CI-AKI and controls using high-throughput RNA sequencing. In total, 910 differentially expressed (DE) lncRNAs (DElncRNAs), including 415 downregulated and 495 upregulated lncRNAs, were identified at 12 h after intra-arterial iodinated contrast medium injection (fold change ≥2; P<0.05). Eight DElncRNAs were further selected and validated using reverse transcription-quantitative polymerase chain reaction. A previous study defined microRNA (miRNA) and mRNA expression changes in the same CI-AKI model. In the present study, a lncRNA-mRNA co-expression network comprising 349 DElncRNAs and 202 DEmRNAs was constructed. The function of these DElncRNAs was mainly associated with oxidative stress and inflammation. Additionally, lncRNA-associated competing endogenous RNA (ceRNA) analysis revealed a network comprising 40 DElncRNA nodes, 5 DEmiRNA nodes and 59 DEmRNA nodes. Among which, the carnosine dipeptidase 1-specific and the transmembrane protein 184B-specific networks were likely to be associated with CI-AKI. The results of the present study revealed the expression profile and potential roles of lncRNAs in CI-AKI, and provide a framework for further mechanistic studies.

Long noncoding RNA ZFAS1 aggravates spinal cord injury by binding with miR-1953 and regulating the PTEN/PI3K/AKT pathway

Multiple evidence has shown that long non-coding RNAs (lncRNAs) are novel modulators in the development of many neurological diseases, including spinal cord injury (SCI). Recently, a novel lncRNA zinc finger antisense 1 (ZFAS1) has been found to facilitate the development of many human diseases. However, the effect of ZFAS1 in SCI has not been explored. In the present study, we used the SCI mouse models and LPS-treated BV-2 cellular models to explore the role of ZFAS1 in SCI. Basso Mouse Scale score was applied to reveal locomotor function. Cresyl violet staining was used to reveal volume of spared myelin around the lesion in the injured cord. RIP and luciferase reporter assay were applied to detect binding capacity among RNAs. Next, ZFAS1 was identified to be upregulated in spinal cord tissues of SCI mice. ZFAS1 knockdown promoted functional recovery and inhibited cell apoptosis and the inflammatory response in SCI mice. ZFAS1 bound with microRNA 1953 (miR-1953), and miR-1953 was downregulated in spinal cord tissues of SCI mice. Furthermore, we confirmed that ZFAS1 promoted SCI progression via binding with miR-1953. In addition, phosphatase and tensin homolog (PTEN) was verified to be a downstream target for miR-1953 in vitro, and PTEN was upregulated in spinal cord tissues of SCI mice. Finally, we illustrated that ZFAS1 inactivated the PI3K/AKT pathway through upregulation of PTEN. In conclusion, our study revealed that ZFAS1 facilitated SCI by binding with miR-1953 and regulating the PTEN/PI3K/AKT pathway, which may provide a potential novel insight for treatment of SCI.

Association between Diabetes Mellitus and Contrast-Associated Acute Kidney Injury: A Systematic Review and Meta-Analysis of 1.1 Million Contrast Exposure Patients

BACKGROUND

Although diabetes mellitus (DM) has been a common risk factor of contrast-associated acute kidney injury (CA-AKI) for a long time, several current studies showed that DM is not an independent risk factor. Due to this diverse finding, we aim to conduct a systematic review assessing the effect of DM on CA-AKI.

METHODS

We searched Ovid Medline, Embase, and Cochrane Database of Systematic Reviews (to June 1, 2020) for studies assessing the association between DM and CA-AKI. Random meta-analysis was performed to derive the pooled estimates of the adjusted odds ratio (OR) and corresponding 95% confidence intervals (CIs).

RESULTS

A total of 84 studies involving 1,136,827 participants were included in this meta-analysis. The presence of DM was associated with an higher risk of CA-AKI (pooled OR: 1.58, 95% CI: 1.48-1.70, I2 = 64%). Furthermore, the predictive effect of elevated CA-AKI for was stronger in the subgroup of DM patients with chronic kidney disease (CKD) (OR: 2.33, 95% CI: 1.21-4.51), while the relationship between DM and CA-AKI was not significant in subgroup patients without CKD (OR: 1.12, 95% CI: 0.73-1.72).

CONCLUSION

This is the first meta-analysis to prove that DM is an independent risk factor of CA-AKI in patients. While the predictive value of DM for CA-AKI in patients with normal kidney function was weakened, more protective treatments are needed in diabetic patients with kidney dysfunction to avoid the occurrence of CA-AKI.

Long non-coding RNAs in head and neck squamous cell carcinoma: Diagnostic biomarkers, targeted therapies, and prognostic roles

At present, emerging evidence shows that non-coding RNAs (ncRNAs) play crucial roles for development of multiple tumors. Amongst these ncRNAs, long non-coding RNAs (lncRNAs) play prominent roles in physiological and pathological processes. LncRNAs are RNA transcripts larger than 200 nucleotides and have been shown to serve important regulatory roles in different types of cancer via interactions with DNA, RNA and proteins. Head and neck squamous cell carcinoma (HNSCC) is one of the most malignant tumors with low survival rates in advanced stages. Recently, lncRNAs have been demonstrated to be involved in a wide range of biological processes, including proliferation, metastasis, and prognosis of HNSCC. Therefore, this review describes molecular mechanisms of up- or down-regulation of lncRNAs and expounds their functions in pathology and clinical practices in HNSCC. It also highlights their potential clinical applications as biomarkers for the diagnosis, prognosis, and treatment of HNSCC. However, studies on lncRNAs are still not comprehensive, and more investigations are needed in the future.

Acetylbritannilactone attenuates contrast-induced acute kidney injury through its anti-pyroptosis effects

Contrast-induced acute kidney injury (CI-AKI) is a severe complication caused by intravascular applied radial contrast media (CM). Pyroptosis is a lytic type of cell death inherently associated with inflammation response and the secretion of pro-inflammatory cytokines following caspase-1 activation. The aim of the present study was to investigate the protective effects of acetylbritannilactone (ABL) on iopromide (IOP)-induced acute renal failure and reveal the underlying mechanism. In vivo and in vitro, IOP treatment caused renal damage and elevated the caspase-1 (+) propidium iodide (PI) (+) cell count, interleukin (IL)-1β and IL-18 levels, lactate dehydrogenase (LDH) release, and the relative expression of nucleotide-binding domain, leucine-rich repeat containing protein 3 (NLRP3), apoptosis-associated speck-like protein (ASC), and gasdermin D (GSDMD), suggesting that IOP induces AKI via the activation of pyroptosis. Furthermore, the pretreatment of ABL partly mitigated the CI-AKI, development of pyroptosis, and subsequent kidney inflammation. These data revealed that ABL partially prevents renal dysfunction and reduces pyroptosis in CI-AKI, which may provide a therapeutic target for the treatment of CM-induced AKI.

Role of Circular RNA in Kidney-Related Diseases

The kidney is vital in maintaining fluid, electrolyte, and acid–base balance. Kidney-related diseases, which are an increasing public health issue, can happen to people of any age and at any time. Circular RNAs (circRNAs) are endogenous RNA that are produced by selective RNA splicing and are involved in progression of various diseases. Studies have shown that various kidney diseases, including renal cell carcinoma, acute kidney injury, and chronic kidney disease, are linked to circRNAs. This review outlines the characteristics and biological functions of circRNAs and discusses specific studies that provide insights into the function and potential of circRNAs for application in the diagnosis and treatment of kidney-related diseases.

LncRNA TUG1 regulates the development of ischemia-reperfusion mediated acute kidney injury through miR-494-3p/E-cadherin axis

Background

Acute kidney injury (AKI) results from renal dysfunction caused by various causes, resulting in high mortality. The underlying mechanisms of ischemia-reperfusion (I/R) induced AKI is very complicated and needed for further research. Here, we sought to found out the functions of lncRNA TUG1 in I/R-induced AKI.

Methods

In vivo model was constructed by I/R-induced mice and in vitro model was constructed by hypoxia/reoxygenation (H/R)-induced HK-2 cell. Kidney tissue damage was evaluated through H&E staining in mice. Cell flow cytometry was used to detect the degree of apoptosis. TUG1, miR-494-3p and E-cadherin were determined both by RT-PCR and western blot. Dual luciferase assay was employed to validate the relationships between TUG1, miR-494-3p and E-cadherin. Inflammatory factors including IL-1β, TNFɑ and IL-6 were evaluated by ELISA.

Results

lncRNA TUG1 was decreased while miR-494-3p was elevated in vivo and in vitro. Overexpression of TUG1 or transfection with miR-494-3p inhibitor significantly alleviated cell apoptosis. MiR-494-3p directly targeted E-cadherin and TUG1 suppressed cell apoptosis via serving as a miR-494-3p sponge to disinhibit E-cadherin.

Conclusion

lncRNA TUG1 alleviated I/R-induced AKI through targeting miR-494-3p/E-cadherin.

Identification of the candidate lncRNA biomarkers for acute kidney injury: a systematic review and meta-analysis

Background: This meta-analysis aims to summarize the studies of lncRNAs dysregulation in individual acute kidney injury (AKI) and identify the potential lncRNA biomarkers of AKI.Research design and methods: We systematically searched four databases to identify the lncRNA expression studies of AKI in animal models and patients. The lncRNAs expression data were extracted from 38 included studies, and lncRNA vote-counting strategy was applied to identify significant lncRNA biomarkers. The predicted targets of lncRNA biomarkers were obtained by searching Co-LncRNA, RBPmap, and LncBase v.2. Further, GO enrichment analysis and KEGG pathway analysis were performed.Results: We recognized a significant lncRNA signature of 21 up-regulated and 11 down-regulated lncRNAs, among which TapSAKI, XIST, MALAT1, CASC2, and HOXA-AS2 were dysregulated both in AKI rodent models and patients. About 28.0% of these lncRNAs mainly exist in the nucleus, which was also the most enriched GO cellular components term. The most relevant GO terms in biological process and molecular function associated with these lncRNAs were splicing, processing, and binding of mRNA.Conclusions: The present meta-analysis identified 31 significant dysregulated lncRNAs from 38 studies. TapSAKI, XIST, MALAT1, CASC2, and HOXA-AS2 were considered as the potential predictive biomarkers and therapeutic targets of AKI.

c-MYC-induced long noncoding RNA MEG3 aggravates kidney ischemia-reperfusion injury through activating mitophagy by upregulation of RTKN to trigger the Wnt/β-catenin pathway

Ischemia-reperfusion injury (IRI)-induced acute kidney injury (AKI) is a life-threatening disease. The activation of mitophagy was previously identified to play an important role in IRI. Maternally expressed 3 (MEG3) can promote cerebral IRI and hepatic IRI. The present study was designed to study the role of MEG3 in renal IRI. Renal IRI mice models were established, and HK-2 cells were used to construct the in vitro models of IRI. Hematoxylin-eosin staining assay was applied to reveal IRI-triggered tubular injury. MitoTracker Green FM staining and an ALP kit were employed for detection of mitophagy. TdT-mediated dUTP-biotin nick-end labeling assay was used to reveal cell apoptosis. The results showed that renal cortex of IRI mice contained higher expression of MEG3 than that of sham mice. MEG3 expression was also elevated in HK-2 cells following IRI, suggesting that MEG3 might participate in the development of IRI. Moreover, downregulation of MEG3 inhibited the apoptosis of HK-2 cells after IRI. Mitophagy was activated by IRI, and the inhibition of MEG3 can restore mitophagy activity in IRI-treated HK-2 cells. Mechanistically, we found that MEG3 can bind with miR-145-5p in IRI-treated cells. In addition, rhotekin (RTKN) was verified to serve as a target of miR-145-5p. MEG3 upregulated RTKN expression by binding with miR-145-5p. Further, MEG3 activated the Wnt/β-catenin pathway by upregulation of RTKN. The downstream effector of Wnt/β-catenin pathway, c-MYC, served as the transcription factor to activate MEG3. In conclusion, the positive feedback loop of MEG3/miR-145-5p/RTKN/Wnt/β-catenin/c-MYC promotes renal IRI by activating mitophagy and inducing apoptosis, which might offer a new insight into the therapeutic methods for renal IRI in the future.

Novel biomarkers for post-contrast acute kidney injury identified from long non-coding RNA expression profiles

Background: Post-contrast acute kidney injury (PC-AKI) is a severe complication of cardiac catheterization. Emerging evidence indicated that long non-coding RNAs (lncRNAs) could serve as biomarkers for various diseases. However, the lncRNA expression profile and potential biomarkers in PC-AKI remain unclear. This study aimed to investigate novel lncRNA biomarkers for the early detection of PC-AKI. Methods: lncRNA profile in the kidney tissues of PC-AKI rats was evaluated through RNA sequencing. Potential lncRNA biomarkers were identified through human-rat homology analysis, kidney and blood filtering in rats and verified in 112 clinical samples. The expression patterns of the candidate lncRNAs were detected in HK-2 cells and rat models to evaluate their potential for early detection. Results: In total, 357 lncRNAs were found to be differentially expressed in PC-AKI. We identified lnc-HILPDA and lnc-PRND were conservative and remarkably upregulated in both kidneys and blood from rats and the blood of PC-AKI patients; these lncRNAs can precisely distinguish PC-AKI patients (area under the curve (AUC) values of 0.885 and 0.875, respectively). The combination of these two lncRNAs exhibited improved accuracy for predicting PC-AKI, with 100% sensitivity and 83.93% specificity. Time-course experiments showed that the significant difference was first noted in the blood of PC-AKI rats at 12 h for lnc-HILPDA and 24 h for lnc-PRND. Conclusion: Our study revealed that lnc-HILPDA and lnc-PRND may serve as the novel biomarkers for early detection and profoundly affect the clinical stratification and strategy guidance of PC-AKI.

Comprehensive analysis of circRNA expression profiles and circRNA-associated competing endogenous RNA networks in IgA nephropathy

Background

Immunoglobulin A nephropathy (IgAN) is immune-mediated primary glomerulonephritis, which is the most common reason leading to renal failure worldwide. The exact pathogenesis of IgAN is not well defined. Accumulating evidence indicates that circular RNAs (circRNAs) play crucial roles in the immune disease by involving in the competing endogenous RNA (ceRNA) network mechanism. At present, the studies of the circRNA profiles and circRNA-associated ceRNA networks in the IgAN are still scarce. This study aimed to elucidate the potential roles of circRNA-associated ceRNA networks of peripheral blood mononuclear cells (PBMCs) in IgAN patients

Method

CircRNA sequencing was used to identify the differential expressed circRNAs (DEcircRNAs) of PBMCs in IgAN and healthy controls; limma packages from data sets GSE25590 and GSE73953 in the Gene Expression Omnibus (GEO) database, were used to identify differentially expressed micro RNAs (miRNAs) and message RNAs (mRNAs). A circRNA-miRNA-mRNA ceRNA network was constructed to further investigate the mechanisms of IgAN. Then, GO analysis and KEGG enrichment analyses were used to annotate the genes involved in the circRNA-associated ceRNA network. Further, Protein-protein interaction (PPI) networks were established to screen potential hub genes, by using Search Tool for the Retrieval of Interacting Genes/Proteins (STRING). Last, a quantitative real-time polymerase chain reaction (qRT-PCR) was applied to verify the hub genes in the ceRNA network.

Result

A total of 145 circRNAs, 22 miRNAs, and 1,117 mRNAs were differentially expressed in IgAN compared with controls (P < 0.05). A ceRNA network was constructed which contained 16 DEcircRNAs, 72 differential expressed mRNAs (DEmRNAs) and 11 differential expressed miRNAs (DEmiRNAs). KEGG pathway enrichment analysis illustrated the underlying biological functions of the ceRNA-associated genes, such as Nitrogen compound metabolic process, COPII-coated ER to Golgi transport vesicle, CAMP response element protein binding process (P < 0.01); meanwhile, Hepatitis B, GnRH signaling, and Prion disease were the most significant enrichment GO terms (P < 0.01). PPI network based on STRING analysis identified 4 potentially hub genes. Finally, Ankyrin repeat and SOCS box containing 16 (ASB16), SEC24 homolog C, COPII coat complex component (SEC24C) were confirmed by qRT-PCR (P < 0.05) and were identified as the hub genes of the ceRNA network in our study.

Conclusion

Our study identified a novel circRNA-mediated ceRNA regulatory network mechanisms in the pathogenesis of IgAN.

LINC00052 ameliorates acute kidney injury by sponging miR-532-3p and activating the Wnt signaling pathway

Acute kidney injury (AKI) is a complex renal disease. Long non-coding RNAs (lncRNAs) have frequently been associated with AKI. In the present study, we aimed to investigate the molecular mechanism(s) of LINC00052 in AKI. We found that LINC00052 expression was significantly decreased in AKI patient serum. In addition, in a hypoxic AKI cell model, LINC00052 expression was strongly elevated. In an I/R-triggered AKI rat model, the expression of TNF-α, IL-6 and IL-1β mRNA was strongly elevated. Moreover, we predicted miR-532-3p to be targeted by LINC00052 in AKI. Overexpression of LINC00052 increased hypoxia-induced inhibition of NRK-52E cell proliferation and reversed hypoxia-triggered apoptosis. Furthermore, we found that induction of TNF-α, IL-6 and IL-1β was repressed by overexpression of LINC00052. LINC00052 decreased hypoxia-induced ROS and MDA accumulation in vitro and increased SOD activity. Decreased levels of c-myc and cyclin D1 were observed in renal tissues of AKI rats. Lastly, Wnt/β-catenin signaling was inactivated in NRK-52E cells experiencing hypoxia, and LINC00052 upregulation reactivated Wnt/β-catenin signaling by sponging miR-532-3p. Taken together, these results suggest that LINC00052 ameliorates AKI by sponging miR-532-3p and activating Wnt signaling.

Changing Expression Profiles and Inclination to Competing Endogenous RNA Networks on MAPK Signaling Pathways of Human Adipose-Derived Stem Cells in a Direct Current Electric Field

Adipose-derived stem cells (ADSCs) are an abundant cell source and provide an easy way to harvest mesenchymal stem cells, which are the focus of considerable attention in regenerative medicine. Electric fields (EF) play roles in many biological events and have been reported to promote cell proliferation, migration, and differentiation. In this study, ADSCs were treated with a direct current electric field (DCEF) of either 0 (control group) or 300 mV/mm (EF group) for six hours. RNA screening and analysis revealed that 66, 164, 26, and 1310 circRNAs, lncRNAs, miRNAs, and mRNAs, respectively, were differentially expressed in the DCEF-treated ADSCs compared with untreated ADSCs. Differentially expressed mRNAs were enriched in the MAPK signaling pathway, TNF signaling pathway, and some other pathways. ANXA1, ERRFI1, JAG1, EPHA2, PRR9, and H2AFY2 were related to the keratinocyte differentiation process. Competing endogenous RNA (ceRNA) networks were constructed on the basis of genes in the MAPK signaling pathway. Twenty-one RNAs in the above networks were randomly chosen, and their expression was validated using qRT-PCR, which showed the same expression trends as the RNA sequencing analysis. The MAPK signaling pathway is of great importance in the ADSC processes that occur in a DCEF, including keratinocyte differentiation. Several ceRNAs may participate in the regulation of MAPK signaling. This study may give new insight into the proliferation, migration, and differentiation of ADSCs, which will be valuable for tissue engineering and regenerative medicine.

MicroRNA as an early diagnostic biomarker for contrast-induced acute kidney injury

Contrast-induced acute kidney injury (CI-AKI) is a common clinical complication and an important cause of increased mortality, prolonged hospitalization, and increased medical costs. For taking effective interventions in CI-AKI, early diagnosis and active prevention are of key importance. Currently, early CI-AKI detection depends on serum creatinine (Scr) levels, which lags behind the actual time of renal injury and seriously affects early diagnosis and interventions. MicroRNA (miRNA) has been found to be a useful biomarker in early CI-AKI diagnosis. Several studies have reported on tissue and time-specific miRNAs in AKI as effective diagnostic biomarkers and potential therapeutic targets, but there are only a few studies on miRNA in CI-AKI. However, these studies are preliminary exploratory investigations on changes in miRNA expression in CI-AKI, and whether these specific miRNAs can be used as biomarkers for early CI-AKI diagnosis and as clinical therapeutic targets requires systematic and in-depth studies. Therefore, more sensitive and specific miRNAs of CI-AKI could be discovered, providing newer options and development directions for early diagnosis and intervention in clinical CI-AKI practice. This review evaluates the research progress on specific miRNAs in the early diagnosis of CI-AKI with an aim of providing basic data for the clinical application of these molecular markers in CI-AKI.

PCAT1 induced by transcription factor YY1 promotes cholangiocarcinoma proliferation, migration and invasion by sponging miR-216a-3p to up-regulate oncogene BCL3

This study was designed to illustrate the function and role of PCAT1 in CCA. The relative expression was confirmed by RT-qPCR and western blot. The biological function of PCAT1 was evaluated by CCK8, EdU, colony formation, wound healing, transwell, and subcutaneous tumor formation assays. Protein levels of EMT markers were measured by western blot. The binding relationship was predicted by JASPAR and starBase. The binding of YY1 to PCAT1 promoter was assessed by ChIP and luciferase reporter. The binding capacity between miR-216a-3p and PCAT1 as well as BCL3 was assessed by luciferase reporter and AGO2-RIP assays. In this study, we found that PCAT1 was up-regulated in CCA tissues and cells, and the PCAT1 overexpression was associated with poor prognosis. Moreover, PCAT1 was assessed as an independent risk factor of prognosis for CCA patients. Amplified PCAT1 was found to promote tumor proliferation, migration, invasion and EMT process, whereas PCAT1 knockdown inhibited these malignant phenotypes. Mechanistically, PCAT1 was predominantly localized in the cytoplasm and competitively bound miR-216a-3p to increase BCL3 expression. In addition, PCAT1 was activated by transcription factor YY1. This study revealed that PCAT1 acted as an oncogene in CCA, and the YY1/PCAT1/miR-216a-3p/BCL3 axis exhibited critical functions in CCA progression.

LncRNA NEAT1 regulated inflammation and apoptosis in a rat model of sepsis-induced acute kidney injury via MiR-27a-3p/TAB3 axis

This study explored the mechanism of NEAT1 in sepsis-induced AKI rats. Cecal ligation punctures (CLP)-induced AKI rats were injected with siRNA-NEAT1 lentivirus. Kidney histopathology and apoptosis were evaluated via hematoxylin-eosin and TUNEL staining, respectively. ELISA determined the levels of Blood urea nitrogen (BUN), serum creatinine (SCr), neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), TNF-α, Interleukin (IL)-1β, and IL-6. Colorimetry measured malondialdehyde (MDA), superoxide dismutase (SOD) activities. qPCR analyzed NEAT1, miR-27a-3p, TAB3, Bcl-2, and Bax expressions. siNEAT1 reversed the promotive effect of CLP on kidney histopathological injury, and BUN, SCr, NGAL, KIM-1, TNF-α, IL-1β, IL-6, MDA, and Bax levels and apoptosis, but raised CLP-downregulated SOD and Bcl-2 levels. NEAT1 sponged miR-27a-3p which targeted TAB3. siNEAT1 upregulated miR-27a-3p and downregulated TAB3 expression. TAB3 overexpression reversed the inhibitory effect of siNEAT1 on the LPS-induced apoptosis of HK-2 cells. siNEAT1 alleviated sepsis-induced AKI in rats and LPS-induced sepsis of cells via miR-27a-3p/TAB3 axis.

Transcriptome sequencing of circular RNA reveals a novel circular RNA-has_circ_0114427 in the regulation of inflammation in acute kidney injury

Acute kidney injury (AKI) is a common serious syndrome characterized by rapid decrease of glomerular filtration rate and the progressive increase of serum creatinine. Circular RNAs (circRNAs) are regulatory RNAs that recently became popular among various diseases. However, the expression profile and function of circRNAs in AKI remain largely unknown. The main function of circRNAs is acting as competing endogenous RNAs (ceRNAs) by binding with microRNAs (miRNAs), as indicated by recent research. In the present study, we established cisplatin-induced AKI model in mice and isolated renal tubular tissues to extract circRNAs for next-generation sequencing (NGS) and bioinformatics analysis. We analyzed the composition, distribution and Gene Ontology terms of circRNAs in cisplatin-induced AKI and revealed differentially expressed circRNAs related to AKI. By finding homologous genes between mouse and human, we identified circRNA- circ-0114427 in humans. We further investigated its function in AKI cell model. Circ-0114427 expression was significantly up-regulated in different AKI cell models. Knockdown of circ-0114427 indicated that circ-0114427 bound to miR-494 as a miRNA sponge to regulate ATF3 expression and further affected the expression of downstream cytokine IL-6. Circ-0114427 regulates inflammatory progression in AKI's early stage via circ-0114427/miR-494/ATF3 pathway. Our findings reveal the expression profile of circRNAs in cisplatin-induced AKI and provide a novel insight into the regulatory mechanism of circRNAs, which may become a new molecular target resource for early diagnosis and treatment strategies.

The Role of MicroRNA in Contrast-Induced Nephropathy: A Scoping Review and Meta-Analysis

Objective

Early diagnosis of contrast-induced nephropathy (CIN) remains crucial for successful treatment; unfortunately, the widely used serum creatinine is elevated only in the late stage of CIN. The circulating microRNAs (miRNAs) are stable biomarker that might be useful. The aim of this scoping review and meta-analysis is to assess the role of miRNAs in CIN.

Methods

We performed a systematic literature search on topics that assess the role of miRNAs in CIN from several electronic databases.

Results

There were 6 preclinical studies and 2 of them validated their findings in human. Only miR-30a, miR-30c, miR-30e, and miR-188 have been validated in human models. Meta-analysis showed that increase in miR-30a expression was associated with higher incidence of CIN (OR 4.48 [1.52, 13.26],  p = 0.007; I²: 94%, p < 0.001). An increase in miR-30e expression was associated with higher incidence of CIN (OR 2.34 [1.70, 3.20], p < 0.001; I²: 0%, p = 0.76). There is an indication that miR-188 is associated with contrast-induced apoptosis and might potentially be a drug target in the future.

Conclusion

This study highlighted the importance of certain miRNAs in CIN pathophysiology. Future researches should explore on the prognostic and therapeutic implication of miRNA in CIN.

Circular RNA in renal diseases

Circular RNA (circRNA) is a newly described type of non-coding RNA. Active research is greatly enriching the current understanding of the expression and role of circRNA, and a large amount of evidence has implicated circRNA in the pathogenesis of certain renal diseases, such as renal cell carcinoma, acute kidney injury, diabetic nephropathy and lupus nephritis. Studies have found evidence that circRNAs regulate programmed cell death, invasion, and metastasis and serve as biomarkers in renal diseases. Recently, circRNAs were identified in exosomes secreted by the kidneys. Nevertheless, the function of circRNA in renal diseases remains ambiguous. Given that circRNAs are regulators of gene expression, they may be involved in the pathology of multiple renal diseases. Additionally, emerging evidence is showing that circulating circRNAs may serve as novel biomarkers for renal disease. In this review, we have summarized the identification, biogenesis, degradation, and functions of circRNA and have evaluated the roles of circRNA in renal diseases.

Long noncoding RNA Gm20319, acting as competing endogenous RNA, regulated GNE expression by sponging miR-7240-5p to involve in deoxynivalenol-induced liver damage in vitro

The regulatory effects of competing endogenous RNA (ceRNA) network have been highlighted on the occurrence and development of diseases. However, the effect of ceRNA network in liver with subchronic deoxynivalenol (DON) exposure has remained unclear so far. Here, lncRNA Gm20319-miR-7240-5p-GNE (glucosamine UDP-N-acetyl-2-epimerase/N-acetylmannosamine kinase) network was identified in DON exposed-liver tissues after DON exposure for 90 days. Subchronic DON exposure induced the mild inflammation in liver tissues. In DON-treated liver tissues and Hepa 1-6 cell line, the expression of Gm20319 and GNE were both downregulated while miR-7240-5p expression was upregulated. The gain- and loss-of-function expression in vitro revealed there was a mutual repression between Gm20319 and miR-7240-5p, and they regulated GNE expression in an opposite direction. Dual luciferase reporter assays showed miR-7240-5p inhibited Gm20319 and GNE expression by directly binding. Co-transfection experiment in vitro revealed Gm20319 and miR-7240-5p could indirectly regulate sialic acid level by directly modulating GNE expression, thereby also influencing the expression of SOD1 and IL-1β. This study revealed Gm20319-miR-7240-5p-GNE network reduced sialic acid level to influence the expression of SOD1 and IL-1β in liver, which might involve in liver damage induced by DON. Gm20319 might be a potential research molecular target for DON-induced liver damage.

The Expression of microRNA in Adult Rat Heart with Isoproterenol-Induced Cardiac Hypertrophy

Cardiac hypertrophy is a common pathological condition and an independent risk factor that triggers cardiovascular morbidity. As an important epigenetic regulator, miRNA is widely involved in many biological processes. In this study, miRNAs expressed in rat hearts that underwent isoprenaline-induced cardiac hypertrophy were identified using high-throughput sequencing, and functional verification of typical miRNAs was performed using rat primary cardiomyocytes. A total of 623 miRNAs were identified, of which 33 were specifically expressed in cardiac hypertrophy rats. The enriched pathways of target genes of differentially expressed miRNAs included the FoxO signaling pathway, dopaminergic synapse, Wnt signaling pathway, MAPK (mitogen-activated protein kinase) signaling pathway, and Hippo signaling pathway. Subsequently, miR-144 was the most differentially expressed miRNA and was subsequently selected for in vitro validation. Inhibition of miR-144 expression in primary myocardial cells caused up-regulation of cardiac hypertrophy markers atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP). The dual luciferase reporter system showed that ANP may be a target gene of miR-144. Long non-coding RNA myocardial infarction associated transcript (LncMIAT) is closely related to heart disease, and here, we were the first to discover that LncMIAT may act as an miR-144 sponge in isoproterenol-induced cardiac hypertrophy. Taken together, these results enriched the understanding of miRNA in regulating cardiac hypertrophy and provided a reference for preventing and treating cardiac hypertrophy.

Circular RNA hsa_circ_0004277 contributes to malignant phenotype of colorectal cancer by sponging miR-512-5p to upregulate the expression of PTMA

In recent years, extensive reports have been published concerning the molecular mechanism underlying the occurrence and progression of colorectal cancer. Circular RNAs (circRNAs) have been identified as important modulators in the biological processes of colorectal cancer. Microarray analysis unveiled that differential circ-0004277 expression was identified in tissue samples of colorectal cancer. High circ-0004277 expression was then verified in tissue samples and cell lines of colorectal cancer via qRT-PCR. Kaplan-Meier analysis was used for identifying the association between circ-0004277 expression and the overall survival rate of colorectal cancer patients. A relationship existed between higher circ-0004277 expression and decreased overall survival rate of colorectal cancer patients. From a functional perspective, circ-0004277 knockdown accelerated cell apoptosis and restrained cell proliferation of colorectal cancer. From mechanistic perspective, circ-0004277 upregulated PTMA by sponging miR-512-5p. Rescue assay was used for verifying the roles of the circ-0004277-miR-512-5p-PTMA axis. Both miR-512-5p and PTMA participated in circ-0004277-mediated colorectal cancer cell proliferation based on experiments. In summary, our study showed that circ-0004277 promoted the proliferation of colorectal cancer cells as a miR-512-5p sponge to upregulate the PTMA expression.