MicroRNA-194 overexpression protects against hypoxia/reperfusion-induced HK-2 cell injury through direct targeting Rheb

Unraveling the Role of Ras Homolog Enriched in Brain (Rheb1 and Rheb2): Bridging Neuronal Dynamics and Cancer Pathogenesis through Mechanistic Target of Rapamycin Signaling

Ras homolog enriched in brain (Rheb1 and Rheb2), small GTPases, play a crucial role in regulating neuronal activity and have gained attention for their implications in cancer development, particularly in breast cancer. This study delves into the intricate connection between the multifaceted functions of Rheb1 in neurons and cancer, with a specific focus on the mTOR pathway. It aims to elucidate Rheb1's involvement in pivotal cellular processes such as proliferation, apoptosis resistance, migration, invasion, metastasis, and inflammatory responses while acknowledging that Rheb2 has not been extensively studied. Despite the recognized associations, a comprehensive understanding of the intricate interplay between Rheb1 and Rheb2 and their roles in both nerve and cancer remains elusive. This review consolidates current knowledge regarding the impact of Rheb1 on cancer hallmarks and explores the potential of Rheb1 as a therapeutic target in cancer treatment. It emphasizes the necessity for a deeper comprehension of the molecular mechanisms underlying Rheb1-mediated oncogenic processes, underscoring the existing gaps in our understanding. Additionally, the review highlights the exploration of Rheb1 inhibitors as a promising avenue for cancer therapy. By shedding light on the complicated roles between Rheb1/Rheb2 and cancer, this study provides valuable insights to the scientific community. These insights are instrumental in guiding the identification of novel targets and advancing the development of effective therapeutic strategies for treating cancer.

Exploring the Therapeutic Significance of microRNAs and lncRNAs in Kidney Diseases

MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are two crucial classes of transcripts that belong to the major group of non-coding RNAs (ncRNAs). These RNA molecules have significant influence over diverse molecular processes due to their crucial role as regulators of gene expression. However, the dysregulated expression of these ncRNAs constitutes a fundamental factor in the etiology and progression of a wide variety of multifaceted human diseases, including kidney diseases. In this context, over the past years, compelling evidence has shown that miRNAs and lncRNAs could be prospective targets for the development of next-generation drugs against kidney diseases as they participate in a number of disease-associated processes, such as podocyte and nephron death, renal fibrosis, inflammation, transition from acute kidney injury to chronic kidney disease, renal vascular changes, sepsis, pyroptosis, and apoptosis. Hence, in this current review, we critically analyze the recent findings concerning the therapeutic inferences of miRNAs and lncRNAs in the pathophysiological context of kidney diseases. Additionally, with the aim of driving advances in the formulation of ncRNA-based drugs tailored for the management of kidney diseases, we discuss some of the key challenges and future prospects that should be addressed in forthcoming investigations.

Molecular profiling of urinary extracellular vesicles in chronic kidney disease and renal fibrosis

Chronic kidney disease (CKD) is a long-term kidney damage caused by gradual loss of essential kidney functions. A global health issue, CKD affects up to 16% of the population worldwide. Symptoms are often not apparent in the early stages, and if left untreated, CKD can progress to end-stage kidney disease (ESKD), also known as kidney failure, when the only possible treatments are dialysis and kidney transplantation. The end point of nearly all forms of CKD is kidney fibrosis, a process of unsuccessful wound-healing of kidney tissue. Detection of kidney fibrosis, therefore, often means detection of CKD. Renal biopsy remains the best test for renal scarring, despite being intrinsically limited by its invasiveness and sampling bias. Urine is a desirable source of fibrosis biomarkers as it can be easily obtained in a non-invasive way and in large volumes. Besides, urine contains biomolecules filtered through the glomeruli, mirroring the pathological state. There is, however, a problem of highly abundant urinary proteins that can mask rare disease biomarkers. Urinary extracellular vesicles (uEVs), which originate from renal cells and carry proteins, nucleic acids, and lipids, are an attractive source of potential rare CKD biomarkers. Their cargo consists of low-abundant proteins but highly concentrated in a nanosize-volume, as well as molecules too large to be filtered from plasma. Combining molecular profiling data (protein and miRNAs) of uEVs, isolated from patients affected by various forms of CKD, this review considers the possible diagnostic and prognostic value of uEVs biomarkers and their potential application in the translation of new experimental antifibrotic therapeutics.

miR-122-5p Regulates Renal Fibrosis In Vivo

The role of exogenous microRNAs (miRNAs) in renal fibrosis is poorly understood. Here, the effect of exogenous miRNAs on renal fibrosis was investigated using a renal fibrosis mouse model generated by unilateral ureteral obstruction (UUO). miRNA microarray analysis and quantitative reverse-transcription polymerase chain reaction showed that miR-122-5p was the most downregulated (0.28-fold) miRNA in the kidneys of UUO mice. The injection of an miR-122-5p mimic promoted renal fibrosis and upregulated COL1A2 and FN1, whereas an miR-122-5p inhibitor suppressed renal fibrosis and downregulated COL1A2 and FN1. The expression levels of fibrosis-related mRNAs, which were predicted targets of miR-122-5p, were evaluated. The expression level of TGFBR2, a pro-fibrotic mRNA, was upregulated by the miR-122-5p mimic, and the expression level of FOXO3, an anti-fibrotic mRNA, was upregulated by the miR-122-5p inhibitor. The protein expressions of TGFBR2 and FOXO3 were confirmed by immunohistochemistry. Additionally, the expression levels of LC3, downstream anti-fibrotic mRNAs of FOXO3, were upregulated by the miR-122-5p inhibitor. These results suggest that miR-122-5p has critical roles in renal fibrosis.

Polyethylene glycol capped gold nanoparticles ameliorate renal ischemia-reperfusion injury in diabetic mice through AMPK-Nrf2 signaling pathway

The aim of this study is to investigate the protective effect of polyethylene glycol capped gold nanoparticles (PEG-AuNPs) on renal ischemia-reperfusion injury (I/R)-induced acute kidney injury (AKI) in diabetic mice via the activation of adenosine 5' monophosphate-activated protein kinase-nuclear factor erythroid-2-related factor-2 (AMPK-Nrf2) pathway. Diabetes was induced in male mice (12/group) by streptozotocin (50 mg/kg) for 5 consecutive days. After 4 weeks, the mice have intravenously received doses of PEG-AuNPs (40, 150, and 400 µg/kg body weight) for 3 consecutive days, and then animals were subjected to 30 min ischemia and 48 h reperfusion. Following the treatment with three different doses of PEG-AuNPs, the levels of blood urea nitrogen (BUN) and creatinine were reduced. Obvious reduction in renal tubular atrophy, glomerular damage, mitochondrial damage, and necrotic area were ultra-structurally detected, and renal interstitial inflammation and apoptosis were diminished. Moreover, PEG-AuNPs increased the recovering of damaged renal cells, suppressed significantly levels of malondialdehyde (MDA), downregulated significantly the level of inflammatory cytokines (TNF-α and IL-1β), and upregulated the AMPK-Nrf2 pathway. PEG-AuNPs exhibited a promising alternative therapeutic target for diabetic renal I/R-induced AKI through upregulation of AMPK/PI3K/AKT path which additionally stimulated Nrf2-regulated antioxidant enzymes in a dose-dependent manner.

MicroRNA expression profiling in acute kidney injury

The aim of this study was to identify miRNAs that regulate AKI and develop their applications as diagnostic biomarkers and therapeutic agents. First, kidney tissues from two different AKI mouse models, namely, AKI induced by the administration of lipopolysaccharide (LPS) causing sepsis (LPS-AKI mice) and AKI induced by renal ischemia-reperfusion injury (IRI-AKI mice), were exhaustively screened for their changes of miRNA expression compared with that of control mice by microarray analysis followed by quantitative RT-PCR. The initial profiling newly identified miRNA-5100, whose expression levels significantly decreased in kidneys in both LPS-AKI mice and IRI-AKI mice. Next, the administration of miRNA-5100-mimic conjugated with a nonviral vector, polyethylenimine nanoparticles (PEI-NPs), via the tail vein significantly induced miRNA-5100 overexpression in the kidney and prevented the development of IRI-AKI mice by inhibiting several apoptosis pathways in vivo. Furthermore, serum levels of miRNA-5100 in patients with AKI were identified as significantly lower than those of healthy subjects. ROC analysis showed that the serum expression level of miRNA-5100 can identify AKI (cut-off value 0.14, AUC 0.96, sensitivity 1.00, specificity 0.833, p<0.05). These results suggest that miRNA-5100 regulates AKI and may be useful as a novel diagnostic biomarker and therapeutic target for AKI.

Hypoxic/Ischemic Inflammation, MicroRNAs and δ-Opioid Receptors: Hypoxia/Ischemia-Sensitive Versus-Insensitive Organs

Hypoxia and ischemia cause inflammatory injury and critically participate in the pathogenesis of various diseases in various organs. However, the protective strategies against hypoxic and ischemic insults are very limited in clinical settings up to date. It is of utmost importance to improve our understanding of hypoxic/ischemic (H/I) inflammation and find novel therapies for better prevention/treatment of H/I injury. Recent studies provide strong evidence that the expression of microRNAs (miRNAs), which regulate gene expression and affect H/I inflammation through post-transcriptional mechanisms, are differentially altered in response to H/I stress, while δ-opioid receptors (DOR) play a protective role against H/I insults in different organs, including both H/I-sensitive organs (e.g., brain, kidney, and heart) and H/I-insensitive organs (e.g., liver and muscle). Indeed, many studies have demonstrated the crucial role of the DOR-mediated cyto-protection against H/I injury by several molecular pathways, including NLRP3 inflammasome modulated by miRNAs. In this review, we summarize our recent studies along with those of others worldwide, and compare the effects of DOR on H/I expression of miRNAs in H/I-sensitive and -insensitive organs. The alternation in miRNA expression profiles upon DOR activation and the potential impact on inflammatory injury in different organs under normoxic and hypoxic conditions are discussed at molecular and cellular levels. More in-depth investigations into this field may provide novel clues for new protective strategies against H/I inflammation in different types of organs.

LncRNA TUG1 attenuates ischaemia-reperfusion-induced apoptosis of renal tubular epithelial cells by sponging miR-144-3p via targeting Nrf2

Renal ischaemia/reperfusion (I/R) injury may induce kidney damage and dysfunction, in which oxidative stress and apoptosis play important roles. Long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) are reported to be closely related to renal I/R, but the specific molecular mechanism is still unclear. The purpose of this research was to explore the regulatory effect of lncRNA TUG1 on oxidative stress and apoptosis in renal I/R injury. This research revealed that in renal I/R injury and hypoxia/reperfusion (H/R) injury in vitro, the expression level of lncRNA TUG1 was upregulated, and oxidative stress levels and apoptosis levels were negatively correlated with the expression level of lncRNA TUG1. Using bioinformatics databases such as TargetScan and microRNA.org, microRNA-144-3p (miR-144-3p) was predicted to be involved in the association between lncRNA TUG1 and Nrf2. This study confirmed that the level of miR-144-3p was significantly reduced following renal I/R injury and H/R injury in vitro, and miR-144-3p was determined to target Nrf2 and inhibit its expression. In addition, lncRNA TUG1 can reduce the inhibitory effect of miR-144-3p on Nrf2 by sponging miR-144-3p. In summary, our research shows that lncRNA TUG1 regulates oxidative stress and apoptosis during renal I/R injury through the miR-144-3p/Nrf2 axis, which may be a new treatment target for renal I/R injury.

Antagonist targeting miR‑106b‑5p attenuates acute renal injury by regulating renal function, apoptosis and autophagy via the upregulation of TCF4

Acute renal injury (ARI) is a life‑threatening condition and a main contributor to end‑stage renal disease, which is mainly caused by ischemia‑reperfusion (I/R). miR‑106b‑5p is a kidney function‑related miRNA; however, whether miR‑106b‑5p regulates the progression of ARI remains unclear. The present study thus aimed to examine the effects of miR‑106b‑5p antagonist on the regulation of ARI progression. It was found that miR‑106b‑5p expression was upregulated in the renal tissue of rats with I/R‑induced ARI and in NRK‑52E rat renal proximal tubular epithelial cells subjected to hypoxia‑reoxygenation (H/R). In vitro, H/R induction suppressed the proliferation, and promoted the apoptosis and autophagy of NRK‑52E cells, whereas miR‑106b‑5p antagonist (inhibition of miR‑106b‑5p) promoted the proliferation, and attenuated the apoptosis and autophagy of NRK‑52E cells under the H/R condition. Dual luciferase reporter gene assay validated that transcription factor 4 (TCF4) was a target of miR‑106b‑5p. It was further found that TCF4 overexpression promoted the proliferation, and inhibited the apoptosis and autophagy of NRK‑52E cells subjected to H/R. Moreover, the effects of miR‑106b‑5p antagonist on NRK‑52E cell proliferation, apoptosis and autophagy were mediated through the regulation of TCF4. In vivo, miR‑106b‑5p antagonist reduced the severity of renal injury, decreased cell proliferation in renal tissues and lowered the serum creatinine (Scr) and blood urea nitrogen (BUN) levels in the blood samples from rats with I/R‑induced ARI. On the whole, the findings presented herein demonstrate that miR‑106b‑5p antagonist attenuates ARI by promoting the proliferation, and suppressing the apoptosis and autophagy of renal cells via upregulating TCF4.

Dysregulation of microRNA and Intracerebral Hemorrhage: Roles in Neuroinflammation

Intracerebral hemorrhage (ICH) is a major public health problem and devastating subtype of stroke with high morbidity and mortality. Notably, there is no effective treatment for ICH. Neuroinflammation, a pathological hallmark of ICH, contributes to both brain injury and repair and hence, it is regarded as a potential target for therapeutic intervention. Recent studies document that microRNAs, small non-coding RNA molecules, can regulate inflammatory brain response after ICH and are viable molecular targets to alter brain function. Therefore, there is an escalating interest in studying the role of microRNAs in the pathophysiology of ICH. Herein, we provide, for the first time, an overview of the microRNAs that play roles in ICH-induced neuroinflammation and identify the critical knowledge gap in the field, as it would help design future studies.

Downregulation of lncRNA TUG1 attenuates inflammation and apoptosis of renal tubular epithelial cell induced by ischemia-reperfusion by sponging miR-449b-5p via targeting HMGB1 and MMP2

We aimed to evaluate the functions of long non-coding RNA taurine upregulated gene 1 (lncRNA TUG1) in renal ischemia-reperfusion (I/R) injury and identify the potential mechanisms. Pathological changes of renal tissues were examined using H&E staining after mimic renal I/R injury in vivo. The contents of serum renal functional parameters and inflammatory factors were measured. The expression of TUG1 and miR-449b-5p in renal tissues and HK-2 cells stimulated by I/R were detected. Then, the effects of TUG1 silencing on inflammation and apoptosis of cells were evaluated. Dual luciferase reporter assays were executed for determining the correlation between miR-449b-5p and TUG1, high mobility group box 1 (HMGB1), or matrix metalloproteinase 2 (MMP2). Subsequently, cells were co-transfected with miR-449b-5p mimic and pcDNA3.1 TUG1. The levels of inflammation, apoptosis, and the expression of HMGB1 and MMP2 were detected. The results revealed that renal tissues were obviously damaged after I/R accompanied by changes in renal functional markers and inflammatory factors. TUG1 was highly expressed whereas miR-449b-5p was lowly expressed. TUG1 silencing reduced the inflammation and apoptosis. Dual luciferase reporter assays confirmed that miR-449b-5p was a target of TUG1 as well as HMGB1 and MMP2 were direct targets of miR-449b-5p. Meanwhile, miR-449b-5p mimic presented the same results with TUG1 silencing, which were reversed after TUG1 overexpression. Moreover, MMP2 and HMGB1 expression was decreased after miR-449b-5p overexpression while that of was increased after TUG1 overexpression. These findings demonstrated that TUG1 silencing attenuates I/R-induced inflammation and apoptosis via targeting miR-449b-5p and regulating HMGB1 and MMP2 expression.

Effect of circular RNA, mmu_circ_0000296, on neuronal apoptosis in chronic cerebral ischaemia via the miR-194-5p/Runx3/Sirt1 axis

Chronic cerebral ischaemia (CCI) is a common pathological disorder, which is associated with various diseases, such as cerebral arteriosclerosis and vascular dementia, resulting in neurological dysfunction. As a type of non-coding RNA, circular RNA is involved in regulating the occurrence and development of diseases, such as ischaemic brain injury. Here, we found that HT22 cells and hippocampus treated with CCI had low expression of circ_0000296, Runx3, Sirt1, but high expression of miR-194-5p. Overexpression of circ_0000296, Runx3, Sirt1, and silenced miR-194-5p significantly inhibited neuronal apoptosis induced by CCI. This study demonstrated that circ_0000296 specifically bound to miR-194-5p; miR-194-5p bound to the 3'UTR region of Runx3 mRNA; Runx3 directly bound to the promoter region of Sirt1, enhancing its transcriptional activity. Overexpression of circ_0000296 by miR-194-5p reduced the negative regulatory effect of miR-194-5p on Runx3, promoted the transcriptional effect of Runx3 on Sirt1, and inhibited neuronal apoptosis induced by CCI. mmu_circ_0000296 plays an important role in regulating neuronal apoptosis induced by CCI through miR-194-5p/Runx3/Sirt1 pathway.

Silence of Long Noncoding RNA SNHG14 Alleviates Ischemia/Reperfusion-Induced Acute Kidney Injury by Regulating miR-124-3p/MMP2 Axis

Purpose

Ample evidence has proved that lncRNAs are pivotal regulators in acute kidney injury (AKI). Here, we focus on the role and mechanism of lncRNA SNHG14 in ischemia/reperfusion- (I/R-) caused AKI.

Methods

I/R and hypoxia/reoxygenation (H/R) were applied to induce rats and HK-2 cells to establish AKI models in vivo and in vitro. Relative expression of SNHG14, miR-124-3p, and MMP2 was determined by qRT-PCR. HE staining was used to evaluate pathological changes in renal tissues, and acute tubular necrosis (ATN) score was calculated. Renal function was evaluated by measuring serum creatinine content and blood urea nitrogen content. Levels of IL-1β, IL-6, and TNF-α were measured by ELISA. Cell viability was examined by MTT assay. Oxidative stress was assessed by measuring SOD, MDA, and ROS levels. The target of SNHG14 or miR-124-3p was verified by DLR assay. Protein expression of MMP2 was examined by western blot.

Results

SNHG14 was boosted in renal tissues of I/R-stimulated rats and H/R-induced HK-2 cells, while miR-124-3p was diminished in H/R-stimulated HK-2 cells. Si-SNHG14 or miR-124-3p mimics repressed inflammation and oxidative stress and enhanced cell viability in H/R-stimulated HK-2 cells. Sh-SNHG14 mitigated I/R-induced AKI in rats. MiR-124-3p was targeted by SNHG14, and MMP2 was targeted by miR-124-3p. Inhibition of miR-124-3p or upregulation of MMP2 reversed inhibitory effects of SNHG14 silence on inflammation and oxidative stress as well as the promoting effect of SNHG14 silence on cell viability in H/R-induced HK-2 cells.

Conclusion

Knockdown of SNHG14 alleviated I/R-induced AKI by miR-124-3p-mediated downregulation of MMP2.

MiR-194 targets Runx1/Akt pathway to reduce renal fibrosis in mice with unilateral ureteral obstruction

PURPOSE

Chronic kidney disease (CKD) has become a global public health problem and accompanied by renal fibrosis. MiR-194, a tumor suppressor gene, has been previously reported to be associated with the pathogenesis of tissue fibrosis. However, the role of miR-194 in the pathogenesis of renal fibrosis remains unknown.

METHODS

A renal fibrosis model was constructed by unilateral ureteral obstruction (UUO) in male C57BL/6 mice. HE and MASSON stainings were used for histological analysis. The expression level of miR-194 was detected by RT-qPCR. The protein expression was detected by western blotting. The levels of inflammatory cytokines were detected by ELISA. The relationship between miR-194 and Runx1 was further verified by dual luciferase reporter assay.

RESULTS

The results showed that miR-194 level was downregulated in kidney tissue of UUO mice, accompanied by significantly pathological damage and renal fibrosis. MiR-194 mimics significantly reduced pathological damage and alleviated renal fibrosis that caused by UOO, and inhibited the expression levels of α-SMA and collagen I. In addition, miR-194 mimics also reduced the expression level of serum inflammatory factors. Moreover, in vitro analysis indicated that Runx1 was a downstream target gene of miR-194. Furthermore, mechanism analysis indicated that miR-194 reduced mouse renal fibrosis by inhibiting the Runx1/AKT pathway in vivo and in vitro.

CONCLUSION

The present findings suggested that miR-194 targets Runx1/Akt pathway to reduce renal fibrosis in UOO-induced mice. This study provides a novel strategy for the prevention and treatment of renal fibrosis.

Suppressed nuclear factor-kappa B alleviates lipopolysaccharide-induced acute lung injury through downregulation of CXCR4 mediated by microRNA-194

Acute lung injury (ALI) is a highly lethal pulmonary disease that causes edema, hypoxemia and respiratory failure. Recent evidence indicates that nuclear factor-kappa B (NF-κB) plays a crucial role in ALI development. However, the regulatory mechanism of NF-κB on ALI remains enigmatic. In this study, we investigated potential molecular mechanism of NF-κB on ALI induced by lipopolysaccharide (LPS). BALB/c mice were subjected to intratracheal spraying of LPS to generate an ALI mode, with the activity of NF-κB in mice tissues being detected by enzyme linked immunosorbent assay (ELISA), and the number of inflammatory cells in bronchoalveolar lavage fluid being counted. Then, the macrophage cell line RAW264.7 exposed to LPS were treated with ammonium pyrrolidinedithiocarbamate (PDTC) (inhibitor of NF-κB), miR-194 mimic, or oe-chemokine receptor type 4 (CXCR4) separately or in combination. After that, ELISA and reverse transcription quantitative polymerase chain reaction (RT-qPCR) were used to detect the expression level of IL-1β, IL-6, TNF-α, miR-194 and CXCR4, respectively. In addition, the targeting relationship between miR-194 and CXCR4 was verified by dual-luciferase reporter gene assay. The dry/wet ratio of lung and the MPO activity were also measured to assess the inflammatory response in mice. Activation of NF-κB down-regulated the miR-194 expression in LPS-induced ALI. Overexpression of miR-194 alleviated LPS-induced ALI and reduced the expression of inflammatory factors IL-1β, IL-6 and TNF-α via targeting CXCR4. In LPS-induced ALI, NF-κB mediates the CXCR4 expression by inhibiting the expression of miR-194, thus promoting the inflammatory injury of lung.

miR-195-5p alleviates acute kidney injury through repression of inflammation and oxidative stress by targeting vascular endothelial growth factor A

Acute kidney injury (AKI) is a common renal dysfunction. Renal ischemia-reperfusion (I/R) injury contributes to AKI progression. The microRNA miR-195-5p can act as a crucial tumor inhibitor in various cancers. However, the potential biological effects of miR-195-5p on AKI are not well-understood. We found that miR-195-5p levels were decreased in the serum samples of patients with AKI. Next, we determined miR-195-5p expression in the renal tissues of the rats and found that it was downregulated. Renal function was evaluated and confirmed using blood urea nitrogen and serum Cr levels. In parallel, the hypoxia-induced NRK-52E cell model was employed, and miR-195-5p was found to be markedly reduced under hypoxic conditions. Furthermore, miR-195-5p was modulated in NRK-52E cells. miR-195-5p induced NRK-52E cell proliferation and protected NRK-52E cells against hypoxia-triggered apoptosis. In an I/R mouse model, miR-195-5p alleviated renal injury triggered by I/R. In addition, oxidative stress and inflammatory factor concentrations were assessed using ELISA. The results showed that miR-195-5p mimicked attenuated oxidative stress induced by I/R injury and downregulated the protein expression of inflammatory factors. Moreover, we identified that vascular endothelial growth factor A (VEGFA) was a target gene of miR-195-5p, which could negatively regulate VEGFA expression in vitro. Inhibitors of miR-195-5p subsequently contributed to renal injury, which was reversed by VEGFA loss. In conclusion, miR-195-5p may repress AKI by targeting VEGFA.

Diagnostic and Therapeutic Potential of microRNAs in Acute Kidney Injury

During hospital stay, about 20% of adult patients experience an episode of acute kidney injury (AKI), which is characterized by a rapid decrease in kidney function. Diagnostic tools regarding early diagnosis of kidney dysfunction prior to AKI and markers of renal recovery are not available. Additionally, there is no therapeutic option for the treatment of AKI. Thus, better and more specific diagnostic and therapeutic options are urgently needed in daily clinical practice. NoncodingRNAs (ncRNAs) have come into focus of research in the context of AKI in the last decade. The best characterized group of ncRNAs are microRNAs (miRNAs). An increasing body of literature has shown that miRNAs are involved in the pathogenesis of AKI and that they are promising future tools in the diagnosis and therapy of AKI. However, there are obstacles to be overcome before miRNAs can be transferred to patient care. This review will give an overview of our current knowledge of miRNA involvement in the context of AKI while critically evaluating their diagnostic and therapeutic potential.

Protective effect of dabrafenib on renal ischemia-reperfusion injury in vivo and in vitro

AIMS

Ischemia-reperfusion injury (IRI) is a major cause of acute kidney injury (AKI), which can lead to poor outcome and increased risk of mortality. Dabrafenib (DAB) is an approved cancer treatment. Little is known about the effect of DAB in prevention or treatment of renal IRI.

METHODS

For in vivo experiments, C57BL/6 mice were divided into four groups: sham (no IRI, no DAB), IRI, DAB, and DAB + IRI. IRI was induced by clamping of bilateral renal pedicles for 30 min. For in vitro experiments, HK-2 cells were used to establish the hypoxia/reoxygenation (H/R) injury model, with four groups: control (no H/R, no DAB), H/R, DAB, and DAB + H/R. Renal function and renal histological changes were recorded. Expression of NGAL and KIM-1 proteins and mRNAs were determined by western blotting and qRT-PCR; secretion of inflammatory cytokines (IL-6 and TNF- α) was determined by qRT-PCR; Cell death was determined using the TUNEL assay, measurement of cleaved caspase-3, and flow cytometry. Necroptosis-related proteins were determined by western blotting.

RESULTS

In mice, DAB pretreatment improved renal function and also reduced histological injury, inflammation, cell death, and expression of necroptosis-associated proteins. In HK-2 cells, DAB significantly decreased the levels of NGAL and KIM-1, inflammatory cytokines, cell death, and necroptosis-related proteins.

CONCLUSION

Our in vitro and in vivo experiments indicated that DAB appears to alleviate renal IRI by suppressing cell death and inhibiting inflammatory responses. DAB has potential use for the clinical prevention and treatment of AKI-induced IRI.

MiR-21-3p Plays a Crucial Role in Metabolism Alteration of Renal Tubular Epithelial Cells during Sepsis Associated Acute Kidney Injury via AKT/CDK2-FOXO1 Pathway

Objective

Sepsis and associated acute kidney injury (SAKI) are determined to be closely related to poor prognosis. Because the metabolic alterations of tubular epithelial cells (TECs) are crucial for the occurrence and development of SAKI, we carried out this present study to identify the metabolism changes of TECs during SAKI and relevant mechanisms.

Methods

Rat SAKI model and rat tubular epithelial cell line were used in our study. ELISA was used to determine the serum cytokines levels. Protein expressions were examined with Western-Blotting and the transcriptions of RNAs were determined with qRT-PCR. ADP/ATP assay and Oil Red O staining were used to examine the energy and lipid metabolism, respectively. Dual-luciferase reporter assay was carried out to determine the interactions between miRNA and specific proteins. Cell cycle arrest and apoptosis were determined with flow cytometry.

Results

Sepsis and AKI were induced 12 h after CLP. Energy and lipid metabolism reduced significantly while FOXO1 levels increased remarkably in TECs during SAKI. The expressions of both AKT and CDK2 and the transcriptions of relevant mRNAs reduced significantly in TECs during SAKI while miR-21-3p expression increased remarkably. Both AKT and CDK2 were determined as the direct targets of miR-21-3p. Furthermore, by in vitro experiments, it was demonstrated that FOXO1 levels were regulated by miR-21-3p in TECs via AKT/CDK2 and AKT/CDK2-FOXO1 pathway was crucial in the regulations of miR-21-3p on lipid metabolism, cell cycle arrest, and apoptosis of TECs.

Conclusions

MiR-21-3p mediates metabolism and cell fate alterations of TECs via manipulating AKT/CDK2-FOXO1 pathway, and that is crucial in the regulation of energy metabolism of TECs during SAKI.

Non-Coding RNAs as New Therapeutic Targets in the Context of Renal Fibrosis

Fibrosis, or tissue scarring, is defined as the excessive, persistent and destructive accumulation of extracellular matrix components in response to chronic tissue injury. Renal fibrosis represents the final stage of most chronic kidney diseases and contributes to the progressive and irreversible decline in kidney function. Limited therapeutic options are available and the molecular mechanisms governing the renal fibrosis process are complex and remain poorly understood. Recently, the role of non-coding RNAs, and in particular microRNAs (miRNAs), has been described in kidney fibrosis. Seminal studies have highlighted their potential importance as new therapeutic targets and innovative diagnostic and/or prognostic biomarkers. This review will summarize recent scientific advances and will discuss potential clinical applications as well as future research directions.