Noncoding RNAs in acute kidney injury

Urinary and Plasma miRNAs in the Early Detection of Acute Kidney Injury and Their Possible Role as Therapeutic Targets

Acute Kidney Injury (AKI) is a severe clinical condition featured by a rapid decrease in kidney function in a short period of time. AKI, which is often secondary to sepsis, ischemia-reperfusion and drug toxicity, is associated to high morbidity and mortality. Moreover, it contributes to the development of chronic kidney disease (CKD), due to maladaptive or incomplete repair mechanisms, resulting in renal fibrosis. Small non-coding RNA has recently emerged as a novel biomarker for the early detection and treatment of AKI. In particular, microRNAs (miRNAs) are non-coding RNA molecules of 21-25 nucleotides regulating the expression of protein-coding genes through sequence-specific recognition. Due to their high stability in biological fluids, such as urine and plasma, they can be reliably analyzed and quantified, and for this reason they can be considered potential diagnostic and therapeutic biomarkers. Specifically, miRNAs have been demonstrated to predict AKI before the increase in creatinine levels, thus improving the management of this syndrome. In this review, we provide a comprehensive overview of the role of urinary and plasma miRNAs in the early detection and treatment of AKI.

lncRNA TUG1 and kidney diseases

Long noncoding RNAs (lncRNAs) cover a large class of transcribed RNA molecules that are more than 200 nucleotides in length. An increasing number of studies have shown that lncRNAs control gene expression through different mechanisms and play important roles in a range of biological processes including growth, cell differentiation, proliferation, apoptosis, and invasion. TUG1 was originally discovered in a genomic screen of taurine-treated mouse retinal cells. Previous evidences pointed out that lncRNA TUG1 could inhibit apoptosis and the release of inflammatory factors, improve mitochondrial function, thereby protecting cells from damage, and showing a protective role of TUG1 in diseases. Given that TUG1 has multiple targets and can interfere with multiple steps in the oncogenic process, it has been proposed as a therapeutic target. In this review, we summarize the research progress of lncRNA TUG1 in kidney diseases in the past 8 years, and discuss its related molecular mechanisms.

microRNA-30c attenuates contrast-induced acute kidney injury by reducing renal tubular epithelial cell apoptosis via targeting SOCS1

Contrast-induced acute kidney injury (CIAKI) is a common complication after contrast media administration. Growing evidences implicate microRNA (miR)-30c has a key role in renal diseases. This study aimed to investigate the role and mechanism of miR-30c in CIAKI. CIAKI rat models were established using tail vein injection of omnipaque. MiR-30c was significantly downregulated in CIAKI models both in vivo and in vitro, concomitant with increased cell apoptosis and deteriorated renal injury. Meanwhile, the cell apoptosis, renal dysfunction and renal injury under contrast exposure were alleviated after overexpression of miR-30c. Mechanistically, we demonstrated that miR-30c directly targeted SOCS1, whose downregulation reduced contrast-induced HK-2 cell apoptosis. Furthermore, the upregulation of SOCS1 abolish the protective effect of the overexpression of miR-30c on contrast-induced cell apoptosis. In summary, overexpression of miR-30c inhibited renal tubular epithelial cell apoptosis and mitigated CIAKI via inhibiting the gene of SOCS1.

miRNAs, dd-cf-DNA, and Chemokines as Potential Noninvasive Biomarkers for the Assessment of Clinical Graft Evolution and Personalized Immunosuppression Requirement in Solid Organ Transplantation

ABSTRACT

The use of noninvasive biomarkers may reduce the need for biopsy and guide immunosuppression adjustments during transplantation. The scientific community in solid organ transplantation currently considers that chemokines, T- and B-cell immunophenotypes, and gene expression, among other molecular biomarkers, have great potential as diagnostic and predictive biomarkers for graft evolution; however, in clinical practice, few valid early biomarkers have emerged. This review focuses on the most relevant scientific advances in this field in the last 5 years regarding the role of 3 biomarkers: miRNAs, chemokines, and ddcf-DNA, in both adult and pediatric populations. An update was provided on the scores based on the combination of these biomarkers. The most-featured articles were identified through a literature search of the PubMed database. This review provides a comprehensive analysis of the potential clinical applications of these biomarkers in the diagnosis and prediction of graft outcomes and discusses the reasons why none have been implemented in clinical practice to date. Translating these biomarkers into routine clinical practice and combining them with pharmacogenetics and pharmacokinetic monitoring is challenging; however, it is the key to present/future individualized immunosuppressive therapies. It is essential that they be shown to be applicable and robust in real-life patient conditions and properly evaluate their added value when combined with the standard-of-care factor monitoring for graft clinical assessment. Partnership strategies among scientists, academic institutions, consortia, including expert working groups and scientific societies, and pharmaceutical and/or biotechnology companies should promote the development of prospective, randomized, multicenter intervention studies for adequate clinical validation of these biomarkers and their monitoring frequency, and their commercialization to make them available to transplant physicians.

The roles of TRPC6 in renal tubular disorders: a narrative review

The transient receptor potential canonical 6 (TRPC6) channel, a nonselective cation channel that allows the passage of Ca2+, plays an important role in renal diseases. TRPC6 is activated by Ca2+ influx, oxidative stress, and mechanical stress. Studies have shown that in addition to glomerular diseases, TRPC6 can contribute to renal tubular disorders, such as acute kidney injury, renal interstitial fibrosis, and renal cell carcinoma (RCC). However, the tubule-specific physiological functions of TRPC6 have not yet been elucidated. Its pathophysiological role in ischemia/reperfusion (I/R) injury is debatable. Thus, TRPC6 may have dual roles in I/R injury. TRPC6 induces renal fibrosis and immune cell infiltration in a unilateral ureteral obstruction (UUO) mouse model. Additionally, TRPC6 overexpression may modify G2 phase transition, thus altering the DNA damage checkpoint, which can cause genomic instability and RCC tumorigenesis and can control the proliferation of RCC cells. This review highlights the importance of TRPC6 in various conditions of the renal tubular system. To better understand certain renal disorders and ultimately identify new therapeutic targets to improve patient care, the pathophysiology of TRPC6 must be clarified.

Epigenetics of Hypertensive Nephropathy

Hypertensive nephropathy (HN) is a leading cause of chronic kidney disease (CKD) and end-stage renal disease (ESRD), contributing to significant morbidity, mortality, and rising healthcare costs. In this review article, we explore the role of epigenetic mechanisms in HN progression and their potential therapeutic implications. We begin by examining key epigenetic modifications-DNA methylation, histone modifications, and non-coding RNAs-observed in kidney disease. Next, we discuss the underlying pathophysiology of HN and highlight current in vitro and in vivo models used to study the condition. Finally, we compare various types of HN-induced renal injury and their associated epigenetic mechanisms with those observed in other kidney injury models, drawing inferences on potential epigenetic therapies for HN. The information gathered in this work indicate that epigenetic mechanisms can drive the progression of HN by regulating key molecular signaling pathways involved in renal damage and fibrosis. The limitations of Renin-Angiotensin-Aldosterone System (RAAS) inhibitors underscore the need for alternative treatments targeting epigenetic pathways. This review emphasizes the importance of further research into the epigenetic regulation of HN to develop more effective therapies and preventive strategies. Identifying novel epigenetic markers could provide new therapeutic opportunities for managing CKD and reducing the burden of ESRD.

microRNAs in kidney diseases: Regulation, therapeutics, and biomarker potential

MicroRNAs (miRNAs) are small, non-coding RNA molecules that play a crucial role in regulating gene expression by inhibiting the translation of their specific target messenger RNAs. To date, numerous studies have demonstrated changes in the expression of miRNAs in the kidneys throughout the progression of both acute kidney injury (AKI) and chronic kidney disease (CKD) in both human patients and experimental models. The role of specific microRNAs in the pathogenesis of kidney diseases has also been demonstrated. Further studies have elucidated the regulation of these microRNAs in diseased kidneys. Besides, certain miRNAs are detected in plasma and/or urine in kidney diseases and are potential diagnostic biomarkers. In this review, we provide an overview of recent developments in our understanding of how miRNAs contribute to kidney diseases. We also explore the potential of miRNAs as both biomarkers and therapeutic targets for these conditions, and highlight future research directions.

Pseudogene GSTM3P1 derived long non-coding RNA promotes ischemic acute kidney injury by target directed microRNA degradation of kidney-protective mir-668

Long non-coding RNAs (lncRNAs) are a group of epigenetic regulators that have been implicated in kidney diseases including acute kidney injury (AKI). However, very little is known about the specific lncRNAs involved in AKI and the mechanisms underlying their pathologic roles. Here, we report a new lncRNA derived from the pseudogene GSTM3P1, which mediates ischemic AKI by interacting with and promoting the degradation of mir-668, a kidney-protective microRNA. GSTM3P1 and its mouse orthologue Gstm2-ps1 were induced by hypoxia in cultured kidney proximal tubular cells. In mouse kidneys, Gstm2-ps1 was significantly upregulated in proximal tubules at an early stage of ischemic AKI. This transient induction of Gstm2-ps1 depends on G3BP1, a key component in stress granules. GSTM3P1 overexpression increased kidney proximal tubular apoptosis after ATP depletion, which was rescued by mir-668. Notably, kidney proximal tubule-specific knockout of Gstm2-ps1 protected mice from ischemic AKI, as evidenced by improved kidney function, diminished tubular damage and apoptosis, and reduced kidney injury biomarker (NGAL) induction. To test the therapeutic potential, Gstm2-ps1 siRNAs were introduced into cultured mouse proximal tubular cells or administered to mice. In cultured cells, Gstm2-ps1 knockdown suppressed ATP depletion-associated apoptosis. In mice, Gstm2-ps1 knockdown ameliorated ischemic AKI. Mechanistically, both GSTM3P1 and Gstm2-ps1 possessed mir-668 binding sites and downregulated the mature form of mir-668. Specifically, GSTM3P1 directly bound to mature mir-668 to induce its decay via target-directed microRNA degradation. Thus, our results identify GSTM3P1 as a novel lncRNA that promotes kidney tubular cell death in AKI by binding mir-668 to inducing its degradation.

Complex Pathophysiology of Acute Kidney Injury (AKI) in Aging: Epigenetic Regulation, Matrix Remodeling, and the Healing Effects of H2S

The kidney is an essential excretory organ that works as a filter of toxins and metabolic by-products of the human body and maintains osmotic pressure throughout life. The kidney undergoes several physiological, morphological, and structural changes with age. As life expectancy in humans increases, cell senescence in renal aging is a growing challenge. Identifying age-related kidney disorders and their cause is one of the contemporary public health challenges. While the structural abnormalities to the extracellular matrix (ECM) occur, in part, due to changes in MMPs, EMMPRIN, and Meprin-A, a variety of epigenetic modifiers, such as DNA methylation, histone alterations, changes in small non-coding RNA, and microRNA (miRNA) expressions are proven to play pivotal roles in renal pathology. An aged kidney is vulnerable to acute injury due to ischemia-reperfusion, toxic medications, altered matrix proteins, systemic hemodynamics, etc., non-coding RNA and miRNAs play an important role in renal homeostasis, and alterations of their expressions can be considered as a good marker for AKI. Other epigenetic changes, such as histone modifications and DNA methylation, are also evident in AKI pathophysiology. The endogenous production of gaseous molecule hydrogen sulfide (H2S) was documented in the early 1980s, but its ameliorative effects, especially on kidney injury, still need further research to understand its molecular mode of action in detail. H2S donors heal fibrotic kidney tissues, attenuate oxidative stress, apoptosis, inflammation, and GFR, and also modulate the renin-angiotensin-aldosterone system (RAAS). In this review, we discuss the complex pathophysiological interplay in AKI and its available treatments along with future perspectives. The basic role of H2S in the kidney has been summarized, and recent references and knowledge gaps are also addressed. Finally, the healing effects of H2S in AKI are described with special emphasis on epigenetic regulation and matrix remodeling.

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.

The mmu_circ_003062, hsa_circ_0075663/miR-490-3p/CACNA1H axis mediates apoptosis in renal tubular cells in association with endoplasmic reticulum stress following ischemic acute kidney injury

BACKGROUND

While recent studies have suggested a potential involvement of circRNAs in acute kidney injury (AKI) after ischemia, mmu_circ_003062 role is undetermined.

METHODS

The levels of mmu_circ_003062, miR-490-3p, CACNA1H, GRP78, CHOP and hsa_circ_0075663 were detected by Relative qPCR in Boston University mouse proximal tubule (BUMPT) cells, mouse kidneys, and human renal tubular epithelial (HK-2) cells. Moreover, the levels of hsa_circ_0075663 in serum and urine of patients with AKI following cardiopulmonary resuscitation (CPR) were detected by absolute quantitative PCR. Western blot was used to detect the relative expression of the protein. The function and regulatory mechanism of mmu_circ_003062 and hsa_circ_0075663 were investigated through a series of in vitro and in vivo experiments, including bioinformatic prediction, luciferase reporter assays, FISH, FCM, TUNEL staining, and H&E staining.

RESULTS

It was found that mmu_circ_003062, hsa_circ_0075663 mediated apoptosis after ischemia/reperfusion (I/R) by interaction with miR-490-3p to enhance CACNA1H expression, thereby leading to the upregulation of endoplasmic reticulum stress (ERS)-relevant proteins GRP78 and CHOP. Ultimately, mmu_circ_003062 downregulation significantly ameliorated ischemic AKI by modulating the miR-490-3p/CACNA1H/GRP78 and CHOP pathway. Furthermore, the plasma and urinary levels of hsa_circ_0075663 in patients with AKI following CPR were significantly higher than non-AKI patients, exhibited a strongly correlation with serum creatinine.

CONCLUSION

The involvement of mmu_circ_003062, hsa_circ_0075663/miR-490-3p/CACNA1H/GRP78 and CHOP axis is significant in the development of ischemic AKI. Moreover, hsa_circ_0075663 has potential as an early diagnostic biomarker.

LncRNAs expression profile in a family household cluster of COVID-19 patients

More than 3 years after the start of SARS-CoV-2 pandemic, the molecular mechanisms behind the viral pathogenesis are still not completely understood. Long non-coding RNAs (lncRNAs), well-known players in viral infections, can represent prime candidates for patients' risk stratification. The purpose of the current study was to investigate the lncRNA profile in a family cluster of COVID-19 cases with different disease progression, during the initial wave of the pandemic and to evaluate their potential as biomarkers for COVID-19 evolution. LncRNA expression was investigated in nasopharyngeal swabs routinely collected for diagnosis. Distinct expression patterns of five lncRNAs (HOTAIR, HOTAIRM1, TMEVPG1, NDM29 and snaR) were identified in all the investigated cases, and they were associated with disease severity. Additionally, a significant increase in the expression of GAS5-family and ZFAS1 lncRNAs, which target factors involved in the inflammatory response, was observed in the sample collected from the patient with the most severe disease progression. An lncRNA prognostic signature was defined, opening up novel research avenues in understanding the interactions between lncRNAs and SARS-CoV-2.

Exploring ncRNA-mediated pathways in sepsis-induced pyroptosis

Sepsis, a potentially fatal illness caused by an improper host response to infection, remains a serious problem in the world of healthcare. In recent years, the role of ncRNA has emerged as a pivotal aspect in the intricate landscape of cellular regulation. The exploration of ncRNA-mediated regulatory networks reveals their profound influence on key molecular pathways orchestrating pyroptotic responses during septic conditions. Through a comprehensive analysis of current literature, we navigate the diverse classes of ncRNAs, including miRNAs, lncRNAs, and circRNAs, elucidating their roles as both facilitators and inhibitors in the modulation of pyroptotic processes. Furthermore, we highlight the potential diagnostic and therapeutic implications of targeting these ncRNAs in the context of sepsis, aiming to cover the method for novel and effective strategies to mitigate the devastating consequences of septic pathogenesis. As we unravel the complexities of this regulatory axis, a deeper understanding of the intricate crosstalk between ncRNAs and pyroptosis emerges, offering promising avenues for advancing our approach to sepsis intervention. The intricate pathophysiology of sepsis is examined in this review, which explores the dynamic interaction between ncRNAs and pyroptosis, a highly regulated kind of programmed cell death.

Circular RNAs in glioma: Molecular functions and pathological implications

Circular RNAs (circRNAs) are a special class of non-coding RNAs with the ring structure. They are stable, abundant and conservative across mammals. The biogenesis and molecular properties of circRNAs are being elucidated, which exert regulatory functions not only through miRNA and protein sponge, but also via translation and exosomal interaction. Accumulating studies have demonstrated that circRNAs are aberrantly expressed in various diseases, especially in cancer. Glioma is one of the most common malignant cerebral neoplasms with poor prognosis. The accurate diagnosis and effective therapies of glioma have always been challenged, there is an urgent need for developing promising therapeutic intervention. Therefore, exploring novel biomarkers is crucial for diagnosis, treatment and prognosis of the glioma which can provide better assistance in guiding treatment. Recent findings found that circRNAs are systematically altered in glioma and may play critical roles in glioma tumorigenesis, proliferation, invasion and metastasis. Due to their distinct functional properties, they are considered as the potential therapeutic targets, diagnostic and prognostic biomarkers. This review elaborates on current advances towards the biogenesis, translation and interaction of circRNAs in many diseases and focused on the role of their involvement in glioma progression, highlighting the potential value of circRNAs in glioma.

The role of non-protein-coding RNAs in ischemic acute kidney injury

Acute kidney injury (AKI) is a condition characterized by a rapid decline in kidney function within a span of 48 hours. It is influenced by various factors including inflammation, oxidative stress, excessive calcium levels within cells, activation of the renin-angiotensin system, and dysfunction in microcirculation. Ischemia-reperfusion injury (IRI) is recognized as a major cause of AKI; however, the precise mechanisms behind this process are not yet fully understood and effective treatments are still needed. To enhance the accuracy of diagnosing AKI during its early stages, the utilization of innovative markers is crucial. Numerous studies suggest that certain noncoding RNAs (ncRNAs), such as long noncoding RNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs), play a central role in regulating gene expression and protein synthesis. These ncRNAs are closely associated with the development and recovery of AKI and have been detected in both kidney tissue and bodily fluids. Furthermore, specific ncRNAs may serve as diagnostic markers and potential targets for therapeutic interventions in AKI. This review aims to summarize the functional roles and changes observed in noncoding RNAs during ischemic AKI, as well as explore their therapeutic potential.

CIRCUSP42 AMELIORATES LPS-INDUCED HUMAN RENAL EPITHELIAL CELLS IN VITRO BY REGULATING THE MIR-182-5P/DUSP1 AXIS

ABSTRACT

Background: Sepsis is a life-threatening systemic inflammatory disease that can cause many diseases, including acute kidney injury (AKI). Increasing evidence showed that a variety of circular RNAs were considered to be involved in the development of the disease. In this study, we aimed to elucidate the role and potential mechanism of circUSP42 in sepsis-induced AKI. Methods: HK2 cells were treated with lipopolysaccharide (LPS) to establish septic AKI cell model. The expression levels of circUSP42, microRNA-182-5p (miR-182-5p), and DUSP1 in LPS-treated HK2 cells were measured by quantitative real-time polymerase chain reaction or Western blot. Functional experiments were performed by using Cell Counting Kit-8, 5-ethynyl-2'-deoxyuridine staining, flow cytometry, oxidative stress assay, and enzyme-linked immunosorbent assay. The potential target binding site between miR-182-5p and CircUSP42 or DUSP1 was verified by dual-luciferase reporter and RNA immunoprecipitation assays. Results: CircUSP42 and DUSP1 were downregulated in serum samples from patients with AKI and LPS-treated HK2 cells, while miR-182-5p was upregulated. Functionally, overexpression of CircUSP42 promoted cell proliferation and inhibited apoptosis, inflammation, and oxidative stress in LPS-triggered HK2 cells. Further mechanism analysis showed that miR-182-5p had potential binding sites with circUSP42 and DUSP1, and circUSP42 regulated LPS-induced cell damage by targeting miR-182-5p. At the same time, miR-182-5p knockdown inhibited LPS-treated HK2 cell damage by regulating DUSP1. In addition, circUSP42 induced DUSP1 expression via sponging miR-182-5p to ameliorate LPS-induced HK2 cell damage. Conclusion : Our results showed that circUSP42 overexpression might attenuate LPS-induced HK2 cell injury by regulating miR-182-5p/DUSP1 axis. This might provide therapeutic strategy for the treatment of sepsis.

Circ_0006944 aggravates LPS-induced HK2 cell injury via modulating miR-205-5p/UBL4A pathway

Circular RNAs (circRNAs) has been manifested to be involved in the development of human diseases, including sepsis-associated acute kidney injury (SA-AKI). However, the function and mechanism of circ_0006944 in SA-AKI has not been validated. Lipopolysaccharide (LPS) was utilised to induce AKI cell model. Levels of genes and proteins were monitored by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot. Cell counting kit 8 assay, EdU assay and flow cytometry were exploited to estimate cell proliferation and apoptosis. The concentrations of inflammation factors were measured via using ELISA assay. The levels of MDA and SOD were tested by the corresponding kits. The relationship between miR-205-5p and circ_0006944 or UBL4A was verified by dual-luciferase reporter assay and RIP assay. Circ_0006944 was overexpressed in SA-AKI patients, and interference of circ_0006944 restrained LPS-stimulated HK2 cell proliferation repression, apoptosis, inflammation and oxidative stress. Mechanistically, circ_0006944 could sponge miR-205-5p, and miR-205-5p interference counteracted circ_0006944 inhibition-mediated impact on the biological functions in LPS-induced HK2 cell. Additionally, UBL4A was targeted by miR-205-5p, and UBL4A overexpression also partially abolished the repressive impacts of miR-205-5p on LPS-triggered HK2 cell damage. Importantly, circ_0006944 sponged miR-205-5p to mediate the expression of UBL4A. Our outcomes identified that circ_0006944 exacerbated SA-AKI development via miR-205-5p/UBL4A axis, which might be a potential treatment and diagnosis biomarker for SA-AKI.

CircRNA itchy E3 ubiquitin protein ligase improves mitochondrial dysfunction in sepsis-induced acute kidney injury by targeting microRNA-214-3p/ATP-binding cassette A1 axis

BACKGROUND

Circular RNAs (circRNAs) are promising biomarkers and therapeutic targets for acute kidney injury (AKI). In this study, we investigated the mechanism by which circRNA itchy E3 ubiquitin protein ligase (circ-ITCH) regulates sepsis-induced AKI.

METHODS

A sepsis-induced AKI mouse model was created using LPS induction and circ-ITCH overexpression. Circ-ITCH levels were confirmed via RT-qPCR. Kidney tissue changes were examined through various stains and TUNEL. Enzyme-linked immunosorbent assay (ELISA) gauged oxidative stress and inflammation. Mitochondrial features were studied with electron microscopy. RT-qPCR and western blotting assessed mitochondrial function parameters. Using starBase, binding sites between circ-ITCH and miR-214-3p, as well as miR-214-3p and ABCA1, were predicted. Regulatory connections were proven by dual-luciferase assay, RT-qPCR, and western blotting.

RESULTS

Circ-ITCH expression was downregulated in LPS-induced sepsis mice. Overexpression of circ-ITCH ameliorates indicators of renal function (serum creatinine [SCr], blood urea nitrogen [BUN], neutrophil gelatinase-associated lipocalin [NGAL], and kidney injury molecule-1 [Kim-1]), reduces renal cell apoptosis, mitigates oxidative stress markers (reactive oxygen species [ROS] and malondialdehyde [MDA]), and diminishes inflammatory markers (interleukin [IL]-1β, IL-6, and tumor necrosis factor [TNF-α]). Moreover, circ-ITCH overexpression alleviated mitochondrial damage and dysfunction. Furthermore, circ-ITCH acts as a sponge for miR-214-3p, thereby upregulating ABCA1 expression. In addition, the miR-214-3p inhibitor repressed oxidative stress, inflammation, and mitochondrial dysfunction, which was reversed by circ-ITCH knockdown. Further cellular analysis in HK-2 cells supported these findings, highlighting the protective role of circ-ITCH against sepsis-induced AKI, particularly through the miR-214-3p/ABCA1 axis.

CONCLUSION

The novel circ-ITCH/miR-214-3p/ABCA1 pathway plays an essential role in the regulation of oxidative stress and mitochondrial dysfunction in sepsis-induced AKI.

CIRC_0002131 CONTRIBUTES TO LPS-INDUCED APOPTOSIS, INFLAMMATION, AND OXIDATIVE INJURY IN HK-2 CELLS VIA INHIBITING THE BINDING BETWEEN MIR-942-5P AND OXSR1

ABSTRACT

Background: Circular RNAs are implicated in the progression of sepsis-associated acute kidney injury (AKI). Circ_0002131 was shown to aggravate cell inflammation and oxidative stress in sepsis-induced AKI. The aim of this study was to investigate the role and underlying mechanism of circ_0002131 in sepsis-induced AKI. Methods: Cell counting Ki-8 assay was used for cell viability detection. Cell apoptosis was measured using flow cytometry. Circ_0002131, microRNA-942-5p (miR-942-5p), and oxidative stress responsive 1 (OXSR1) level analysis was performed through reverse transcription-quantitative polymerase chain reaction assay. The protein levels were examined by western blot. Inflammatory factors were determined using enzyme-linked immunosorbent assay. Oxidative injury was assessed via commercial kits. Target relation was analyzed by dual-luciferase reporter assay and RNA immunoprecipitation assay. Results: HK-2 cell viability was suppressed and apoptosis was enhanced by LPS. Circ_0002131 was highly expressed in LPS-treated HK-2 cells and sepsis-induced AKI patients. LPS-induced apoptosis, inflammation, and oxidative injury of HK-2 cells were attenuated after silence of circ_0002131. Then, miR-942-5p was identified as a target for circ_0002131, and the regulation of circ_0002131 in LPS-induced cell injury was ascribed to reduce miR-942-5p level. In addition, circ_0002131 targeted miR-942-5p to elevate OXSR1 expression. MiR-942-5p prevented LPS-evoked HK-2 cell injury via targeting OXSR1. Conclusion : All results demonstrated that circ_0002131 promoted LPS-mediated HK-2 cell injury via miR-942-5p-mediated upregulation of OXSR1, suggesting that the circ_0002131/miR-942-5p/OXSR1 axis was related to sepsis-induced AKI progression.

A comprehensive overview of exosome lncRNAs: emerging biomarkers and potential therapeutics in endometriosis

Endometriosis is a gynecological condition that significantly impacting women's daily lives. In recent years, the incidence of endometriosis has been rising yearly and is now an essential contributor to female infertility. Exosomes are extracellular vesicles (EVs) that carry long noncoding RNA (lncRNA) and shield lncRNA from the outside environment thanks to their vesicle-like structure. The role of exosome-derived lncRNAs in endometriosis is also receiving more study as high-throughput sequencing technology develops. Several lncRNAs with variable expression may be crucial to the emergence and growth of endometriosis. The early diagnosis of endometriosis will be considerably improved by further high specificity and sensitivity Exosome lncRNA screening. Exosomes assist lncRNAs in carrying out their roles, offering a new target for creating endometriosis-specific medications. In order to serve as a reference for clinical research on the pathogenesis, diagnosis, and treatment options of endometriosis, this paper covers the role of exosome lncRNAs in endometriosis and related molecular mechanisms.

CIRC_0008882 STIMULATES PDE7A TO SUPPRESS SEPTIC ACUTE KIDNEY INJURY PROGRESSION BY SPONGING MIR-155-5P

ABSTRACT

Background: The importance of circular RNA (circRNA) in the progression of septic acute kidney injury (AKI) was gradually recognized. It has been confirmed that circ_0008882 expression was decreased in the blood of patients with AKI. However, the role of circ_0008882 in septic AKI progression remains unclear. Methods: Human kidney-2 (HK2) cells were stimulated with lipopolysaccharide (LPS) to establish a septic AKI cell model. The RNA and protein expression of circ_0008882, miR-155-5p, phosphodiesterase 7A (PDE7A), PCNA, Bax, and Bcl-2 were detected by quantitative real-time polymerase chain reaction and Western blot. Cell viability was investigated by cell counting kit-8 assay. Enzyme-linked immunosorbent assay (ELISA) was adopted to measure the levels of inflammatory factors (TNF-α, IL-1β, and IL-6). Flow cytometry was implemented to evaluate cell cycle and cell apoptosis. The Caspase3 activity was examined using Caspase3 Assay Kit. Dual-luciferase reporter assay and RNA immunoprecipitation assay were applied to verify the molecular target relations. Results: Septic AKI serum samples and LPS-induced HK2 cells displayed low expression of circ_0008882 and PDE7A, and high expression of miR-155-5p when compared with the controls. Overexpression of circ_0008882 relieved LPS-induced HK2 cell injury. MiR-155-5p was a target of circ_0008882, and miR-155-5p mimic restored circ_0008882 overexpression-mediated effects on LPS-treated HK2 cells. PDE7A was identified as a target gene of miR-155-5p, and PDE7A downregulation almost reverted the improvement impacts induced by the miR-155-5p inhibitor. Conclusions: Overexpression of circ_0008882 impeded LPS-induced HK2 cell injury by modulating miR-155-5p/PDE7A pathway, implying that circ_0008882 might be a possible circRNA-targeted therapy for septic AKI.

A comprehensive overview of exosome lncRNAs: Emerging biomarkers and potential therapeutics in gynecological cancers

Ovarian, endometrial, and cervical cancer are common gynecologic malignancies, and their incidence is increasing year after year, with a younger patient population at risk. An exosome is a tiny “teacup-like” blister that can be secreted by most cells, is highly concentrated and easily enriched in body fluids, and contains a large number of lncRNAs carrying some biological and genetic information that can be stable for a long time and is not affected by ribonuclease catalytic activity. As a cell communication tool, exosome lncRNA has the advantages of high efficiency and high targeting. Changes in serum exosome lncRNA expression in cancer patients can accurately reflect the malignant biological behavior of cancer cells. Exosome lncRNA has been shown in studies to have broad application prospects in cancer diagnosis, monitoring cancer recurrence or progression, cancer treatment, and prognosis. The purpose of this paper is to provide a reference for clinical research on the pathogenesis, diagnosis, and treatment of gynecologic malignant tumors by reviewing the role of exosome lncRNA in gynecologic cancers and related molecular mechanisms.

CircNRIP1 KNOCKDOWN ALLEVIATES LIPOPOLYSACCHARIDE-INDUCED HUMAN KIDNEY 2 CELL APOPTOSIS AND INFLAMMATION THROUGH miR-339-5p/OXSR1 PATHWAY

ABSTRACT

Background: CircRNA regulates sepsis-induced acute kidney injury (AKI). CircNRIP1 is overexpressed in the blood of AKI patients, but its role in septic AKI occurrence remains unknown. Methods: Human kidney 2 (HK2) cells were stimulated using lipopolysaccharide (LPS) to generate a septic AKI cell model. The expression levels of circNRIP1, miR-339-5p, oxidative stress-responsive kinase 1 (OXSR1), B-cell lymphoma-2 (Bcl2), BCL2-associated x protein (Bax), and cleaved-caspase 3 were detected by quantitative real-time polymerase chain reaction or Western blotting analysis. Cell viability and apoptosis were investigated by cell counting kit-8 and flow cytometry analysis. The release of proinflammatory cytokines was monitored using commercial kits. The associations among circNRIP1, miR-339-5p, and OXSR1 were identified by mechanism assays. Results: CircNRIP1 was dramatically upregulated in the blood of septic AKI patients and LPS-induced HK2 cells. CircNRIP1 depletion protected HK2 cells from LPS-induced apoptosis and inflammation. MiR-339-5p expression was downregulated in the blood of septic AKI patients, and miR-339-5p combined with circNRIP1. Moreover, circNRIP1 knockdown-induced effects involved the upregulation of miR-339-5p in LPS-treated HK2 cells. Comparatively, OXSR1 expression was increased in the blood of septic AKI patients. MiR-339-5p bound to OXSR1, and circNRIP1 modulated OXSR1 expression by interacting with miR-339-5p. Further, ectopic expression of OXSR1 relieved circNRIP1 knockdown-mediated effects in LPS-induced HK2 cells. Conclusion: CircNRIP1 depletion ameliorated LPS-induced HK2 cell damage by regulating the miR-339-5p/OXSR1 pathway.

The novel biomarker circ_0020339 drives septic acute kidney injury by targeting miR-17-5p/IPMK axis

PURPOSE

Sepsis is a systemic life-threatening inflammatory disease, which leads to septic acute kidney injury (AKI). Circular RNAs (circRNAs) are involved in septic AKI. Herein, we aimed to expound the action of circ_0020339 in septic AKI. The dysregulation of plasma circRNAs between patients with septic non-AKI and patients with septic AKI were screened by circRNA chip.

METHODS

The dysregulation of circ_0020339, microRNA (miR)-17-5p, and inositol polyphosphate multi kinase (IPMK) mRNA was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Cell viability and apoptosis were measured by cell counting kit-8 (CCK-8) and flow cytometry, respectively. The release of serum creatinine (SCr), tissue inhibitor metalloproteinase-2 (TIMP-2), insulin-like growth factor binding protein-7 (IGFBP7), tumor necrosis factor (TNF)α and interleukin (IL)-1β was evaluated by enzyme-linked immunosorbent assay (ELISA). Bioinformatic analysis, dual-luciferase reporter assay and miRNA pull down assay were used to confirm the interaction between miR-17-5p and circ_0020339 or IPMK 3'untranslated region (UTR). Protein level of IPMK, TNF receptor-associated factor 6 (TRAF6), phosphorylated AKT (p-AKT)/total (t)-AKT, p-nuclear factor kappa-B (NF-κB) kinase (p-IKK)/t-IKK, p-inhibitor of NF-κB (p-IκB)α/t-IκBα, and p-p65/t-p65 were conducted by western blot.

RESULTS

Circ_0020339 was upregulated in the plasma of patients with septic AKI as well as LPS-treated HK2 cells and C57BL/6 mice relative to the corresponding counterparts. Functionally, circ_0020339 was positively correlated with markers of renal functional injury and inflammation in patients with septic AKI; si-circ_0020339 facilitated cell proliferation, while restrained cell apoptosis and inflammation in LPS-triggered HK2 cells; meanwhile, si-circ_0020339 restrained survival rate, renal functional injury and inflammation in LPS-triggered C57BL/6 mice. Furthermore, circ_0020339 and IPMK 3'UTR shared the same complementary sites with miR-17-5p.

CONCLUSION

si-circ_0020339 attenuated LPS-induced cell damage by targeting miR-17-5p/IPMK axis and inactivation of TRAF6/p-AKT/p-IKK/p-IκBα/p-p65. Altogether, plasma circ_0020339 serves as a novel diagnostic marker of patients with septic AKI.

RNA sequencing and bioinformatics analysis of circular RNAs in asphyxial newborns with acute kidney injury

As one kind of novel noncoding RNA, circular RNAs (circRNAs) are involved in different biological processes. Although growing evidences have supported the important role of circRNAs in renal diseases, the mechanism remains unclear in neonatal acute kidney injury (AKI). High-throughput sequencing analysis was used to investigate the expression of circRNAs between hypoxia-induced AKI neonates and controls. Bioinformatics analysis was conducted to predict the function of differentially expressed circRNAs. Finally, the differentially expressed circRNAs were screened and determined by quantitative real-time PCR (qPCR). (1) A total of 296 differentially expressed circRNAs were identified (Fold change >2 and p < 0.05). Of them, 184 circRNAs were markedly upregulated, and 112 were significantly downregulated in the AKI group. (2) The pathway analysis showed that ubiquitin-mediated proteolysis, renal cell carcinoma, Jak-STAT, and HIF-1 signaling pathways participated in AKI. (3) Top five upregulated and five downregulated circRNAs with higher fold changes were selected for qPCR validation. Hsa_circ_0008898 (Fold Change = 5.48, p = 0.0376) and hsa_circ_0005519 (Fold Change = 4.65, p = 0.0071) were significantly upregulated, while hsa_circ_0132279 (Fold Change = -4.47, p = 0.0008), hsa_circ_0112327 (Fold Change = -4.26, p = 0.0048), and hsa_circ_0017647 (Fold Change = -4.15, p = 0.0313) were significantly downregulated in asphyxia-induced AKI group compared with the control group. This study could contribute to future research on neonatal AKI and facilitate the identification of novel therapeutic targets.

Noncoding RNA Regulation of Hormonal and Metabolic Systems in the Fruit Fly Drosophila

The importance of RNAs is commonly recognised thanks to protein-coding RNAs, whereas non-coding RNAs (ncRNAs) were conventionally regarded as 'junk'. In the last decade, ncRNAs' significance and roles are becoming noticeable in various biological activities, including those in hormonal and metabolic regulation. Among the ncRNAs: microRNA (miRNA) is a small RNA transcript with ~20 nucleotides in length; long non-coding RNA (lncRNA) is an RNA transcript with >200 nucleotides; and circular RNA (circRNA) is derived from back-splicing of pre-mRNA. These ncRNAs can regulate gene expression levels at epigenetic, transcriptional, and post-transcriptional levels through various mechanisms in insects. A better understanding of these crucial regulators is essential to both basic and applied entomology. In this review, we intend to summarise and discuss the current understanding and knowledge of miRNA, lncRNA, and circRNA in the best-studied insect model, the fruit fly Drosophila.

Role of miRNA dysregulation in sepsis

Background

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

Main body

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

Conclusion

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

Supplementary Information

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

Circulating and urinary microRNAs profile for predicting renal recovery from severe acute kidney injury

Background

There is little known about the contribution of microRNAs (miRNAs) in the recovery from acute kidney injury (AKI). This study aimed to discover and validate miRNA profiles for predicting renal recovery from severe AKI.

Patients and methods

A prospective observational study was conducted between June 2020 and January 2021. Urine and serum samples of participants with AKI stage 3 were collected from two groups: renal recovery and renal non-recovery. Transcriptomic analysis was performed using nCounter miRNA Expression Assay. Expression levels of candidate miRNAs were validated using quantitative real-time polymerase chain reaction (qRT-PCR).

Results

The discovery phase identified 18 and 11 differentially expressed miRNAs that were statistically significant between the two groups in urine and serum specimens, respectively. Top candidate miRNAs selected included miR-556-3p, miR-1915-3p, miR-4284, miR-32-5p, miR-96-5p, and miR-556-5p in urine, and miR-499b-5p, miR-30a-3p, miR-92b-3p and miR-770-5p in serum. This study enrolled 110 participants in the validation phase. The qRT-PCR analysis indicated that urine miR-556-3p was significantly higher in the renal recovery group than in the renal non-recovery group. Urine miR-556-3p alone predicted renal recovery with an area under the curve (AUC) of 0.64 (95%CI 0.52–0.75, p = 0.03). Combining the clinical model with urine miR-556-3p predicted renal recovery with an AUC of 0.83 (95%CI 0.75–0.92, p < 0.01).

Conclusion

This data provides evidence that microtranscriptome profiles of severe AKI patients with renal recovery differed from the non-recovery group. Urine miR-556-3p had the potential to improve the prediction of renal recovery from severe AKI.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40560-022-00637-0.

circVMA21 combining with TAF15 stabilizes SOCS3 mRNA to relieve septic lung injury through regulating NF-κB activation

BACKGROUND

Lung injury is a severe complication of sepsis, which brings great threats and challenges to human health. CircVMA21 has exhibited powerful anti- inflammation capacity. However, its underlying molecule mechanism remains blurry.

METHODS

Lipopolysaccharide (LPS) was used to treat mice and WI-38 cells to establish models of lung injury caused by sepsis. Lung injury was evaluated using HE staining. Cell apoptosis was tested by TUNEL and flow cytometry. Levels of inflammatory cytokines were detected using ELISA assay. CircVMA21 and SOCS3 expression was measured using RT-qPCR. The ROS, MDA, SOD and GSH production were monitored by commercial kits. The protein expression was examined with western blot. The correlations among circVMA21, SOCS3 and TAF15 were confirmed using RIP and RNA-pull down.

RESULTS

The expression of circVMA21 and SOCS3 was downregulated in LPS-induced lung injury of mice and WI-38 cells. Overexpressing circVMA21 or SOCS3 assuaged LPS-induced cell injury through repressing the levels of inflammatory factors, oxidative stress and cell apoptosis. NF-κB signaling pathway was inactivated by circVMA21 or SOCS3 overexpression. circVMA21 enhanced the stabilization of SOCS3 mRNA via interplaying with TAF15. SOCS3 knockdown destroyed the beneficial impacts of circVMA21 overexpression on LPS-induced cell injury.

CONCLUSION

CircVMA21 suppressed LPS-induced the levels of inflammatory factors, oxidative stress and cell apoptosis and improved LPS-induced lung injury by mediating TAF15/SOCS3/NF-κB axis.

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.

MicroRNAs in kidney injury and disease

MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression by degrading or repressing the translation of their target messenger RNAs. As miRNAs are critical regulators of cellular homeostasis, their dysregulation is a crucial component of cell and organ injury. A substantial body of evidence indicates that miRNAs are involved in the pathophysiology of acute kidney injury (AKI), chronic kidney disease and allograft damage. Different subsets of miRNAs are dysregulated during AKI, chronic kidney disease and allograft rejection, which could reflect differences in the physiopathology of these conditions. miRNAs that have been investigated in AKI include miR-21, which has an anti-apoptotic role, and miR-214 and miR-668, which regulate mitochondrial dynamics. Various miRNAs are downregulated in diabetic kidney disease, including the miR-30 family and miR-146a, which protect against inflammation and fibrosis. Other miRNAs such as miR-193 and miR-92a induce podocyte dedifferentiation in glomerulonephritis. In transplantation, miRNAs have been implicated in allograft rejection and injury. Further work is needed to identify and validate miRNAs as biomarkers of graft function and of kidney disease development and progression. Use of combinations of miRNAs together with other molecular markers could potentially improve diagnostic or predictive power and facilitate clinical translation. In addition, targeting specific miRNAs at different stages of disease could be a promising therapeutic strategy.

CircZNF644 aggravates lipopolysaccharide-induced HK-2 cell impairment via the miR-140-5p/MLKL axis

Circular RNAs (circRNAs) play vital roles in human diseases, including acute kidney injury (AKI). In this paper, we focused on the effect of circRNA zinc finger protein 644 (circZNF644) on AKI cell model progression. qRT-PCR was conducted for the levels of circZNF644, ZNF644, miR-140-5p and mixed lineage kinase domain like pseudokinase (MLKL). RNase R assay, actinomycin D assay and subcellular fraction analysis were conducted to analyze the features of circZNF644. CCK-8 assay and EdU assay were used to explore cell proliferation. Flow cytometry analysis was conducted to analyze cell cycle and cell apoptosis. Western blot assay was executed for protein levels. ELISA was performed for the levels of inflammatory cytokines. The relationships among circZNF644, miR-140-5p and MLKL were analyzed by dual-luciferase reporter assay and RIP assay. CircZNF644 was upregulated in LPS-stimulated HK-2 cells. LPS-mediated inhibitory effects on cell proliferation and cell cycle and promotional effects on apoptosis and inflammation were reversed by circZNF644 knockdown. CircZNF644 directly interacted with miR-140-5p and MLKL was the target gene of miR-140-5p. The impact of circZNF644 knockdown on HK-2 cell injury was relieved by miR-140-5p inhibition. Moreover, miR-140-5p enhancement alleviated LPS-triggered HK-2 cell damage, while MLKL elevation reversed the effect. CircZNF644 knockdown protected HK-2 cells from LPS-induced injury by altering miR-140-5p/MLKL pathway, suggesting that circZNF644 may be a hopeful therapeutic target for AKI.

Exosome-Derived Circ_0094343 Promotes Chemosensitivity of Colorectal Cancer Cells by Regulating Glycolysis via the miR-766-5p/TRIM67 Axis

Objective

Currently, the role of circ_0094343 (circPTEN) on the chemosensitivity of CRC remains to be clarified. This study aimed to investigate the role and mechanism of exosome-delivered circ_0094343 in the proliferation, glycolysis, and chemosensitivity of colorectal cancer (CRC) cells.

Methods

Real-time quantitative polymerase chain reaction (qRT-PCR) was utilized to detect the expression level of circ_0094343, miR-766-5p, and TRIM67 (Tripartite motif-containing 67) in CRC clinical tissue samples and cells, transmission electron microscopy (TEM) to observe the morphology of exosomes, and nanoparticle tracking analysis (NTA) system to measure the diameter of exosomes. Besides, PKH67 fluorescent labeling was applied for assessing the level of exosome uptake by cells, MTT and cell clone formation assays for detecting cell proliferation and clone formation, respectively, and related kits for checking the glucose consumption, lactate production, and extracellular acidification rate (ECAR) in cells. Dual-luciferase reporter (DLR) gene assay was used for verifying the targeting relationship between circ_0094343 and miR-766-5p, miR-766-5p and TRIM67, RNA immunoprecipitation (RIP) experiment for the interaction between circ_0094343 and miR-766-5p, and Western blot for the protein level of exosome surface antigens (HSP70, CD63) and TRIM67 in cells in exosomes and cell lysates.

Results

circ_0094343 was significantly downregulated in CRC tissues, chemotherapy-resistant CRC tissues, and metastatic CRC tissues. Moreover, exosomes-carried circ_0094343 played an inhibitory role in the proliferation, clone formation and glycolysis of HCT116 cells. Meanwhile, it could also improve the chemosensitivity of HCT116 cells to 5-fluorouracil (5-FU), oxaliplatin (L-OHP), and doxorubicin (Dox). Additionally, circ_0094343 acted as a sponge for miR-766-5p, and miR-766-5p targeted and regulated TRIM67. In CRC tissues, miR-766-5p expression was negatively correlated with TRIM67 expression, while circ_0094343 was positively associated with TRIM67. Further, mechanistic validation also demonstrated that circ_0094343 could inhibit HCT116 cell proliferation, clone formation, glycolysis, and chemotherapy resistance via the miR-766-5p/TRIM67 axis.

Conclusion

circ_0094343 inhibited the proliferation, clone formation and glycolysis of CRC cells and improved their chemosensitivity to various chemotherapeutic drugs via the miR-766-5p/TRIM67 axis. This finding may provide new insights into the treatment of CRC.

LncRNA 122049 suppresses apoptosis of renal tubular epithelial cells in ischemic AKI by targeting the miR-330-5p/ELK1 axis

Several studies have reported that long non-coding RNAs (LncRNAs) were associated with the progression of acute kidney injury (AKI). However, the role and regulation mechanism of lncRNA122049 in ischemic AKI remains unknown. In the present study, we found that lncRNA 122049 protected against the ischemia/reperfusion (I/R) induced apoptosis in BUMPT cells. Mechanistically, the lncRNA 122049 directly sponged miR-330-5p, then increased the expression of ELK1(ETS transcription factor ELK1) to decrease renal cell apoptosis. In addition, miR-330-5p inhibitor completely reversed the pro-apoptotic effect of LncRNA 122049 siRNA on I/R-induced BUMPT cells apoptosis. Finally, overexpression of lncRNA 122049 attenuated ischemic mice AKI via targeting of the miR-330-5p/ELK1 axis. Collectively, the data demonstrated that LncRNA 122049 prevented the I/R-induced renal cell apoptosis via regulation of the miR-330-5p/ELK1 axis, which brings new insights into the pathogenesis and potential targeted treatment of ischemic AKI.

Mechanism of circHIPK3-miRNA-124-3p/miRNA-148b-3p-Mediated Inflammatory Responses and Cell Senescence in Candida albicans-Induced Septic Acute Kidney Injury

INTRODUCTION

Sepsis is a life-threatening inflammatory state that can result in septic acute kidney injury (SAKI). Circular RNAs (circRNAs) are implicated in various inflammatory diseases including SAKI. This study investigated the effect of circHIPK3 on inflammatory responses and cell senescence in Candida albicans-induced SAKI.

METHODS

circHIPK3 expression and inflammatory factors in the serum of SAKI patients and healthy volunteers were detected. The murine and cell models of SAKI were established by C. albicans and lipopolysaccharide induction, respectively. The effect of circHIPK3 on SAKI inflammatory responses and cell senescence was measured using ELISA, SA-β-gal staining, CCK-8, RT-qPCR, and Western blot. The binding relationships among circHIPK3, miR-124-3p, or miR-148b-3p and KLF6 or DNMT1/3a were confirmed. The binding of KLF6 and NLRP3 was determined, and the methylation level of the Klotho promoter was detected. Functional rescue experiments were performed to verify the effect of miR-124-3p or miR-148b-3p on SAKI.

RESULTS

circHIPK3 was highly expressed in SAKI. circHIPK3 silencing alleviated kidney injury in SAKI mice and enhanced SAKI cell viability by alleviating inflammatory responses and cell senescence. Mechanically, circHIPK3 upregulated KLF6 expression by competitively binding to miR-124-3p, thereby promoting the binding of KLF6 and NLRP3, activating NLRP3/caspase-1-mediated pyroptosis, and eventually aggravating SAKI inflammatory responses. circHIPK3 upregulated DNMT1/3a expression by competitively binding to miR-148b-3p, thus elevating the methylation level of Klotho promoter and accelerating SAKI cell senescence. Downregulation of miR-124-3p or miR-148b-3p attenuated the protective effect of circHIPK3 silencing on SAKI.

CONCLUSION

circHIPK3 aggravated SAKI inflammatory responses via miR-124-3p/KLF6 and accelerated SAKI cell senescence via miR-148b-3p/DNMT1/3a.

MicroRNAs in kidney development and disease

MicroRNAs (miRNAs) belong to a class of endogenous small noncoding RNAs that regulate gene expression at the posttranscriptional level, through both translational repression and mRNA destabilization. They are key regulators of kidney morphogenesis, modulating diverse biological processes in different renal cell lineages. Dysregulation of miRNA expression disrupts early kidney development and has been implicated in the pathogenesis of developmental kidney diseases. In this Review, we summarize current knowledge of miRNA biogenesis and function and discuss in detail the role of miRNAs in kidney morphogenesis and developmental kidney diseases, including congenital anomalies of the kidney and urinary tract and Wilms tumor. We conclude by discussing the utility of miRNAs as potentially novel biomarkers and therapeutic agents.

circSTRN3 aggravates sepsis-induced acute kidney injury by regulating miR-578/ toll like receptor 4 axis

Sepsis is a systemic inflammatory response caused by infection, and severe sepsis is commonly associated with the development of acute kidney injury (AKI). Accumulating evidence has revealed the implication of circular RNAs in AKI. In this study, we explored the potential engagement and the underlying mechanism of hsa_circ_010157 (circSTRN3) in sepsis-induced AKI. CircSTRN3 levels in HK2 cells and serum samples of patients were determined by RT-PCR. The protein levels of TLR4 (Toll Like Receptor 4), bax (Bcl-2-associated X protein), cleaved caspase 3 and bcl-2 (B-cell lymphoma-2) were detected by Western blotting (WB), and the levels of proinflammatory cytokines were detected by ELISA. The molecular interactions between mir-578/TLR4 and circSTRN3/miR-578 were analyzed by dual luciferase reporter assay as well as RNA pull-down experiment. Lipopolysaccharide (LPS) treated HK2 cells were used as an in vitro model to investigate the functional interaction of circSTRN3/miR-578/TLR4 axis. We found that the expression level of circSTRN3 in patients with sepsis-induced AKI and LPS-induced HK2 cells was higher. Silencing cicrSTRN3 alleviated LPS-induced cell proliferation, and suppressed the inflammatory response and apoptosis in LPS-treated HK2 cells. In contrast, the overexpression of circSTRN3 aggravated the cellular damages induced by LPS treatment. CircSTRN3 targeted miR-578/TLR4 axis to influence the damage effect induced by LPS. miR-578 inhibitor or TLR4 overexpression impaired the rescue effect of circSTRN3 knockdown. These results indicate that circSTRN3 upregulation in sepsis-induced AKI modulates miR-578/TLR4 axis to promote the pathogenesis of AKI, which could serve as future therapeutic targets for AKI treatment.

RNA sequencing reveals the emerging role of bronchoalveolar lavage fluid exosome lncRNAs in acute lung injury

Background

Bronchoalveolar lavage fluid (BALF) exosomes possess different properties in different diseases, which are mediated through microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), among others. By sequencing the differentially expressed lncRNAs in BALF exosomes, we seek potential targets for the diagnosis and treatment of acute lung injury (ALI).

Methods

Considering that human and rat genes are about 80% similar, ALI was induced using lipopolysaccharide in six male Wistar rats, with six rats as control (all weighing 200 ± 20 g and aged 6-8 weeks). BALF exosomes were obtained 24 h after ALI. The exosomes in BALF were extracted by ultracentrifugation. The differential expression of BALF exosomal lncRNAs in BALF was analyzed by RNA sequencing. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to predict the functions of differentially expressed lncRNAs, which were confirmed by reverse transcription-polymerase chain reaction.

Results

Compared with the control group, the ALI group displayed a higher wet/dry ratio, tumor necrosis factor-α levels, and interleukin-6 levels (all P < 0.001). The airway injection of exosomes in rats led to significant infiltration by neutrophils. A total of 2,958 differentially expressed exosomal lncRNAs were identified, including 2,524 upregulated and 434 downregulated ones. Five lncRNAs confirmed the reliability of the sequencing data. The top three GO functions were phagocytic vesicle membrane, regulation of receptor biosynthesis process, and I-SMAD binding. Salmonella infection, Toll-like receptor signaling pathway, and osteoclast differentiation were the most enriched KEGG pathways. The lncRNA-miRNA interaction network of the five confirmed lncRNAs could be predicted using miRDB.

Conclusions

BALF-derived exosomes play an important role in ALI development and help identify potential therapeutic targets related to ALI.

High expression of SETDB1 mediated by miR-29a-3p associates with poor prognosis and immune invasion in breast invasive carcinoma

Background

Breast invasive carcinoma (BRCA) has a poor prognosis. Numerous studies have shown that SET domain bifurcated histone lysine methyltransferase 1 (SETDB1) is involved in the initiation and progression of many cancers. This study aims to reveal the potential mechanism of SETDB1 in the development and progression of BRCA.

Methods

The ONCOMINE database, TIMER database, UALCAN database and GEPIA database were used to analyze the expression of SETDB1 in human cancers. We evaluated the expression level of SETDB1 in cell lines by quantitative real-time polymerase chain reaction (qPCR), and the survival analysis of SETDB1 was performed on PrognoScan and Kaplan-Meier plotter websites. The upstream regulator was obtained from starBase database.

Results

We confirmed that SETDB1 messenger RNA (mRNA) level showed high expression in breast cell lines, and we also found that SETDB1 showed high expression in many types of cancers. Moreover, SETDB1 overexpression was positively correlated with poor prognosis in BRCA. Furthermore, we first predicted miR-29a-3p was a potential upstream regulator of SETDB1 in BRCA. Our findings indicated that SETDB1 might play a carcinogenic role by increasing the infiltration of immune cell and influencing immune checkpoint expression.

Conclusions

This study suggested that miR-29a-3p can mediate the expression of SETDB1 with poor prognosis and tumor immune infiltration in BRCA.

Stratifin promotes renal dysfunction in ischemic and nephrotoxic AKI mouse models via enhancing RIPK3-mediated necroptosis

Stratifin (SFN) is a member of the 14-3-3 family of highly conserved soluble acidic proteins, which regulates a variety of cellular activities such as cell cycle, cell growth and development, cell survival and death, and gene transcription. Acute kidney injury (AKI) is prevalent disorder characterized by inflammatory response, oxidative stress, and programmed cell death in renal tubular epithelial cells, but there is still a lack of effective therapeutic target for AKI. In this study, we investigated the role of SFN in AKI and the underlying mechanisms. We established ischemic and nephrotoxic AKI mouse models caused by ischemia-reperfusion (I/R) and cisplatin, respectively. We conducted proteomic and immunohistochemical analyses and found that SFN expression levels were significantly increased in AKI patients, cisplatin- or I/R-induced AKI mice. In cisplatin- or hypoxia/reoxygenation (H/R)-treated human proximal tubule epithelial cells (HK2), we showed that knockdown of SFN significantly reduced the expression of kidney injury marker Kim-1, attenuated programmed cell death and inflammatory response. Knockdown of SFN also significantly alleviated the decline of renal function and histological damage in cisplatin-caused AKI mice in vivo. We further revealed that SFN bound to RIPK3, a key signaling modulator in necroptosis, to induce necroptosis and the subsequent inflammation in cisplatin- or H/R-treated HK2 cells. Overexpression of SFN increased Kim-1 protein levels in cisplatin-treated MTEC cells, which was suppressed by RIPK3 knockout. Taken together, our results demonstrate that SFN that enhances cisplatin- or I/R-caused programmed cell death and inflammation via interacting with RIPK3 may serve as a promising therapeutic target for AKI treatment.

Noncoding RNAs in Drug Resistance of Gastrointestinal Stromal Tumor

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor in the gastrointestinal tracts and a model for the targeted therapy of solid tumors because of the oncogenic driver mutations in KIT and PDGDRA genes, which could be effectively inhibited by the very first targeted agent, imatinib mesylate. Most of the GIST patients could benefit a lot from the targeted treatment of this receptor tyrosine kinase inhibitor. However, more than 50% of the patients developed resistance within 2 years after imatinib administration, limiting the long-term effect of imatinib. Noncoding RNAs (ncRNAs), the non-protein coding transcripts of human, were demonstrated to play pivotal roles in the resistance of various chemotherapy drugs. In this review, we summarized the mechanisms of how ncRNAs functioning on the drug resistance in GIST. During the drug resistance of GIST, there were five regulating mechanisms where the functions of ncRNAs concentrated: oxidative phosphorylation, autophagy, apoptosis, drug target changes, and some signaling pathways. Also, these effects of ncRNAs in drug resistance were divided into two aspects. How ncRNAs regulate drug resistance in GIST was further summarized according to ncRNA types, different drugs and categories of resistance. Moreover, clinical applications of these ncRNAs in GIST chemotherapies concentrated on the prognostic biomarkers and novel therapeutic targets.

Identification of inflammatory response and alternative splicing in acute kidney injury and experimental verification of the involvement of RNA‑binding protein RBFOX1 in this disease

An increasing number of inflammatory responses and alternative splicing (AS) have been recently reported to be associated with various kidney diseases. The effect of inflammatory response on acute kidney injury (AKI) has not been fully clarified. In the present study, a mouse model of AKI induced by cisplatin and ischemia-reperfusion (IR) was established and genome-wide profiling analysis and identification of differentially expressed genes (DEGs) in kidney tissue was conducted by Gene Ontology (GO) functional analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, protein-protein interaction (PPI) network analysis and RT-qPCR. The results revealed that common DEGs in AKI induced by cisplatin and IR were enriched in the inflammatory response pathway, including hub genes CSF-1, CXCL1, CXCL10, IL-1β, IL-34, IL-6 and TLR2. AS in AKI was initially reported. Cisplatin-induced AS was enriched in the phosphorylation pathway, involving regulated AS genes CSNK1A1, PAK2, CRK, ADK and IKBKB. IR-induced AS was enriched in apoptosis and proliferation pathways, including DEGs ZDHHC16, BCL2L1 and FGF1 regulated by AS. The ability of RNA-binding proteins (RBPs) to regulate AS was coordinated with the function of context-dependent genetic mechanisms. A total of 49 common differentially expressed RBP genes were screened. RNA binding fox-1 homolog 1 (RBFOX1) was revealed to be the top downregulated gene. The relative levels of RBFOX1 in the nuclei of mouse renal tubular epithelial cells in mRNA and proteins were downregulated by cisplatin and IR. Moreover, the biological functions of RBFOX1 were investigated in human renal proximal tubular epithelial cells (HK-2 cells). Results of in vitro experiments revealed that exogenous RBFOX1 inhibited inflammation and oxidative stress to reduce hypoxia/reoxygenation-induced apoptosis of HK-2 cells. This phenomenon may be related to the inhibition of NF-κB and the activation of the NRF2/HO-1 signaling pathway. In conclusion, the inflammatory cytokines, AS and RBPs in AKI were analyzed in the present study via whole transcriptome sequencing. It was revealed that the RBP gene RBFOX1 was involved in the pathogenesis of AKI. Thus, the present study provided novel insights into the mechanism of AKI pathogenesis.

Tribulus terrestris L. protects glomerular endothelial cells via the miR155-H2AC6 interaction network in hypertensive renal injury

Background

Hypertensive renal injury is one of the most lethal complications of hypertension. At present, renin-angiotensin-aldosterone system (RAAS) blockers are considered the best drugs for the treatment of renal injury in hypertension because of their nephroprotective effect of reducing proteinuria, but there are no specific drugs for this purpose, however, clinical trials proved that Chinese medicine has a protective effect on target organs in the treatment of hypertension. Tribulus terrestris L. (TrT), a traditional Chinese medicine (TCM), has potential applications due to its reno-protective and immunomodulatory effects.

Methods

We investigated the underlying reno-protective mechanism of TrT on Angiotensin II (AngII)-induced hypertensive renal injury in glomerular endothelial cells by integrating the differential expression profiles of micro RNA (miRNA) and messenger RNA (mRNA) to construct a miRNA-mRNA interaction network associated with hypertensive kidney injury, followed by quantitative real-time polymerase chain reaction (qRT-PCR) for validation.

Results

Seventy-six differentially expressed mRNAs (DEmRNAs) and 1 differentially expressed miRNAs (DEmiRNAs) were identified in the control group and the AngII-induced hypertensive renal injury group, respectively. 110 DEmRNAs and 27 DEmiRNAs were identified in the TrT treatment group and the AngII-induced group, respectively. The core component of the miRNA-mRNA network was miR-155-5p. Our study showed that miR-155-5p expression levels were more decreased in the AngII-induced hypertensive renal injury group than the control group. TrT treatment also significantly upregulated miR-155-5p. Additionally, we found that miR-155-5p expression levels were negatively correlated with H2A clustered histone 6 (H2AC6).

Conclusions

The results of this study indicate that TrT has a reno-protective effect on AngII-induced hypertensive renal injury by miR-155-5p, which negatively regulates the expression of H2AC6. Our findings offer a new therapeutic strategy and have identified an effective candidate target for the treatment of hypertensive renal injury in clinical settings.

Pathway network of pyroptosis and its potential inhibitors in acute kidney injury

Acute kidney injury (AKI) is a worldwide problem, and there is no effective drug to eliminate AKI. The death of renal cells is an important pathological basis of intrinsic AKI. At present, targeted therapy for TEC death is a research hotspot in AKI therapy. There are many ways of cell death involved in the occurrence and development of AKI, such as apoptosis, necrosis, ferroptosis, and pyroptosis. This article mainly focuses on the role of pyroptosis in AKI. The assembly and activation of NLRP3 inflammasome is a key event in the occurrence of pyroptosis, which is affected by many factors, such as the activation of the NF-κB signaling pathway, mitochondrial instability and excessive endoplasmic reticulum (ER) stress. The activation of NLRP3 inflammasome can trigger its downstream inflammatory cytokines, which will lead to pyroptosis and eventually induce AKI. In this paper, we reviewed the possible mechanism of pyroptosis in AKI and the potential effective inhibitors of various key targets in this process. It may provide potential therapeutic targets for novel intrinsic AKI therapies based on pyroptosis, so as to develop better therapeutic strategies.

Circ_0114427 promotes LPS-induced septic acute kidney injury by modulating miR-495-3p/TRAF6 through the NF-κB pathway

BACKGROUNDS

Septic acute kidney injury (AKI) is a severe illness in clinics. Enriching researches investigated the regulatory network of AKI during the past decades, evidences showed that circular RNAs (circRNAs) were involved in the molecular mechanism of human AKI. However, the special responses remain largely elusive. Thus, the study aims to investigate the function of circ_0114427 in the progression of AKI.

METHODS

The levels of circ_0114427, miR-495-3p and Tumour Necrosis Factor Receptor-Associated Factor 6 (TRAF6) were both assessed by quantitative real-time polymerase chain reaction (qRT-PCR). In addition, lipopolysaccharide (LPS) was applied to establish AKI cell model, and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay was carried out to determine the viability of LPS-induced HK-2 cells. The expression of TRAF6, B-cell lymphoma-2 (Bcl-2), Bcl2-associated X (Bax), cleave-caspase 3, caspase 3, total IκBα (t-IκBα), phospho-IκBα (p-IκBα), total p65 (t-p65) and phospho-p65 (p-p65) were all detected via western blot. The levels of IL-1β and TNF-α were identified by western blot and ELISA. What's more, cell apoptosis was measured by flow cytometry. Lastly, dual-luciferase reporter, RNA Immunoprecipitation (RIP) and RNA pull-down assays were employed to verify the relationships between miR-495-3p and circ_0114427 or TRAF6 in vitro.

RESULTS

The level of miR-495-3p was remarkably restrained while circ_0114427 and TRAF6 levels were specially reinforced in AKI patient serum samples and LPS-induced HK-2 cells. Moreover, IL-1β and TNF-α were highly expressed in LPS-induced AKI cells. Functionally, circ_0114427 was a sponge of miR-495-3p, and circ_0114427 silence-mediated effects in LPS-induced HK-2 cells were partly ameliorated by the addition of miR-495-3p inhibitor. Moreover, TRAF6 was a target gene of miR-495-3p, and the inhibiting effect of miR-495-3p on cell apoptosis and inflammatory response was mitigated by TRAF6 overexpression. Mechanistically, the circ_0114427/miR-495-3p/TRAF6 axis modulated cell apoptosis and inflammatory response via NF-κB/p65 signalling pathway in AKI.

CONCLUSION

Circ_0114427 regulated cell apoptosis and inflammatory response through miR-495-3p/TRAF6 axis via NF-κB/p65 signalling pathway, providing a novel mechanism in clinical treatment of AKI patients.HighlightsCirc_0114427 is upregulated in serum specimens from septic AKI patients and LPS-induced HK-2 cells.LPS treatment suppresses cell viability and promotes apoptosis and inflammation in HK-2 cells.Circ_0114427 knockdown ameliorates the effects of LPS on cell viability, apoptosis and inflammation in HK-2 cells.Circ_0114427 regulates LPS-induced HK-2 cell injury by regulating miR-495-3p/TRAF6/NF-κB/p65 axis.

Upregulation of lncRNA NONRATG019935.2 suppresses the p53-mediated apoptosis of renal tubular epithelial cells in septic acute kidney injury

Although increasing evidence has confirmed that the apoptosis of renal tubular epithelial cells (RTECs) is a crucial contributor to the onset and development of septic acute kidney injury (AKI), the pathological mechanism by which RTEC apoptosis is upregulated during septic AKI is not entirely clear. In this study, a rat model of septic AKI was induced by a cecal ligation puncture procedure or lipopolysaccharide (LPS) injection. Four differentially expressed long noncoding RNAs (DE-Lncs) in the rat model of septic AKI were determined using RNA-sequencing and verified by qRT-PCR. Among the four DE-Lncs, the expression level of lncRNA NONRATG019935.2 (9935) exhibited the most significant reduction in both septic AKI rats and LPS-treated NRK-52E cells (a rat RTEC line). The overexpression of 9935 suppressed cell apoptosis and p53 protein level in LPS-treated NRK-52E cells, and retarded septic AKI development in the rat model of septic AKI. Mechanistically, 9935 decreased the human antigen R (HuR)-mediated Tp53 mRNA stability by limiting the combination of HuR and the 3'UTR region of Tp53 mRNA in RTECs. The overexpression of HuR abrogated the inhibitory effect of pcDNA-9935 on the LPS-induced apoptosis of NRK-52E and rat primary RTECs. In conclusion, 9935 exerts its role in septic AKI by suppressing the p53-mediated apoptosis of RTECs, and this essential role of 9935 relies on its destructive effect on HuR-mediated Tp53 mRNA stability.

Ulinastatin Attenuates LPS-Induced Inflammation and Inhibits Endoplasmic Reticulum Stress-Induced Apoptosis in Renal Tubular Epithelial Cells via Regulation of the TLR4/NF-κB and Nrf2/HO-1 Pathways

Acute kidney injury (AKI) is one of the most common diseases in patients treated in intensive care units. This study was intended to explore the underlying mechanism by which ulinastatin (UTI) influenced the inflammation and apoptosis of renal tubular epithelial cells, HK-2.The effects of UTI on the cell viability of HK-2 cells were first measured by MTT and lactate dehydrogenase (LDH) detection kit. The apoptosis and inflammation of HK-2 cells were then determined by TUNEL, western blot, ELISA, and RT-qPCR. Then, the proteins in the Toll-like receptor 4 (TLR4)/nuclear factor κB (NF-κB) and nuclear factor erythroid 2-related factor 2 (Nrf2)/Heme oxygenase 1 (HO-1) signaling pathways were measured by western blot for confirming the relationship between UTI and these pathways. Finally, Nrf-2 inhibitor ML385 and TLR4 activator CCL-34 were respectively used on LPS-induced HK-2 cells exposed to UTI for the conduction of gain-of-function and loss-of-function assays.UTI treatment boosted the cell viability of HK-2 cells damaged by LPS. Furthermore, UTI exposure cut down the apoptosis rate and inhibited the expression inflammatory factors of HK-2 cells induced by LPS. UTI treatment decreased the expression of proteins in the TLR4/NF-κB pathway, increased the HO-1 expression, and prompted the translocation of Nrf2 from the cytoplasm to the nucleus. The alleviated effects of UTI on inflammation and apoptosis LPS-induced HK-2 cells were abolished by ML385 and TLR4, respectively.UTI attenuates LPS-induced inflammation and inhibits endoplasmic reticulum stress-induced apoptosis in renal tubular epithelial cells by regulating TLR4/NF-κB and Nrf2/HO-1 pathways.

The role of miR-199b-3p in regulating Nrf2 pathway by dihydromyricetin to alleviate septic acute kidney injury

The pathophysiology of septic acute kidney injury (AKI) is very complex and the fatality is high. Nrf2 is crucial for septic AKI, and dihydromyricetin (DMY) has a protective effect on LPS-induced AKI. We aimed to explore whether DMY could affect Nrf2 pathway by regulating miR-199b-3p and played a protective role in septic AKI. The mouse model was induced by cecal ligation and puncture (CLP) and the cell model was stimulated by LPS. Enzyme-linked immunosorbent assay was conducted to examine MDA, SOD, LDH, GSH, TNF-α, kidney injury molecule 1 (KIM-1), and IL-6 levels. The pathological changes were observed by hematoxylin-eosin staining. The targeted relationship between miR-199b-3p and Nrf2 was verified by a dual-luciferase reporter assay. Levels of SOD, GSH, NQO-1, Nrf2, and HO-1 were decreased, MDA, LDH, TNF-α, IL-6, and KIM-1, and miR-199b-3p were increased in the CLP group and LPS-induced HK-2 cells, while the effect was reversed after DMY treatment. There existed renal tubule cell edema and necrosis, inflammatory cell infiltration in the CLP group, the situation was partially improved by DMY. MiR-199b-3p bound to Nrf2. Nrf2 levels were increased, TNF-α, IL-6, and KIM-1 were decreased after transfected with miR-199b-3p inhibitor, these effects were reversed when co-transfected with si-Nrf2. TNF-α, IL-6, KIM-1, and miR-199b-3p levels were increased; Nrf2, NQO-1, and HO-1 levels were decreased in the LPS + DMY + mimics-miR group. MiR-199b-3p was increased in septic AKI models, DMY might alleviate septic AKI by regulating miR-199b-3p to affect the Nrf2 pathway.

miR-132-3p promotes the cisplatin-induced apoptosis and inflammatory response of renal tubular epithelial cells by targeting SIRT1 via the NF-κB pathway

Cisplatin is a highly effective and broad-spectrum anticancer drug for the clinical treatment of solid tumors. However, it causes acute kidney injury (AKI) in patients with cancer. Consequently, its clinical application is limited. The occurrence, development, and prognosis of AKI are closely associated with microRNA (miRNA), which needs validation as a biomarker, especially for the early stages of cisplatin-induced AKI. An example of miRNA is miR-132-3p, which plays important roles in inflammatory responses, cell proliferation, and apoptosis in a variety of diseases. However, variations in its expression, potential mechanisms, and downstream targets in cisplatin-induced AKI remain unclear. This study aimed to investigate the functions of miR-132-3p in cisplatin-induced AKI. Sequencing and qRT-PCR revealed that miR-132-3p was significantly upregulated in cisplatin-induced AKI models of mouse and human proximal renal tubular epithelial (HK-2) cells. Apoptosis and inflammatory responses were significantly suppressed by the inhibition of the miR-132-3p expression in cisplatin-stimulated HK-2 cells, and this suppression was blocked by miR-132-3p mimics. Bioinformatics and dual luciferase reporter gene assay identified the 3'- UTR of SIRT1 mRNA as a direct target of miR-132-3p. RNA-FISH and immunofluorescence co-localization demonstrated that miR-132-3p and SIRT1 directly combined and interacted in the cytoplasm of HK-2 cells. Mechanistically, the SIRT1 expression was suppressed and the NF-κB signaling pathway was activated by the upregulation of miR-132-3p in cisplatin-induced AKI. By contrast, the SIRT1 expression was upregulated after the inhibition of miR-132-3p. The ratios of p-p65/p65 and p-IκBα/IκBα were significantly reduced, and the expression levels of inflammatory biomarkers and apoptotic proteins induced by cisplatin were obviously attenuated. Our results suggested that miR-132-3p exacerbated cisplatin-induced AKI by negatively regulating SIRT1 and activating the NF-κB signaling pathway. Therefore, targeting miR-132-3p might be a potential adjuvant therapy for ameliorating AKI in cisplatin-treated patients.