Knockdown of LncRNA DLX6-AS1 inhibits HK-2 cell pyroptosis via regulating miR-223-3p/NLRP3 pathway in lipopolysaccharide-induced acute kidney injury

S-nitrosoglutathione inhibits pyroptosis of kidney tubular epithelial cells in sepsis via the SIRT3/SOD2/mtROS signaling pathway

OBJECTIVES

Pyroptosis is considered to play an important role in the occurrence, development and prognosis of septic acute kidney injury (SAKI). We aimed to explore the specific molecular mechanism of S-nitrosoglutathione (SNG) regulating pyroptosis of kidney tubular epithelial cells (KTECs).

METHODS

By constructing a mice model of sepsis, we pretreated them with SNG and used biochemical methods to detect the levels of serum inflammatory factors and mitochondrial reactive oxygen species (mtROS), assessed the severity of kidney injury and KTECs mitochondrial damage, and detected the expression of KTECs pyroptosis-related proteins and sirtuin 3 (SIRT3)/superoxide dismutase 2 (SOD2) pathway proteins.

RESULTS

The kidney injury caused by sepsis was significantly aggravated, and the levels of IL-1β, IL-6, IL-18, TNF-α, malondialdehyde (MDA) and mtROS were all increased, accompanied by the decrease of SIRT3 and SOD2 proteins, while NOD-like receptor with pyrin domain 3 (NLRP3), gasdermin D (GSDMD), Caspase-1 proteins expression and the number of KTECs apoptotic cells were all increased. However, after SNG pretreatment, the levels of IL-1β, IL-6, IL-18, TNF-α, MDA and mtROS were all significantly decreased, the expression of SIRT3 and SOD2 proteins were increased, NLRP3, GSDMD, Caspase-1 proteins expression and the number of KTECs apoptotic cells were decreased.

CONCLUSIONS

SNG protects SAKI by regulating the SIRT3/SOD2/mtROS signaling pathway to inhibit the pyroptosis of KTECs.

Ferroptosis, necroptosis, and pyroptosis in calcium oxalate crystal-induced kidney injury

Kidney stones represent a highly prevalent urological disorder worldwide, with high incidence and recurrence rates. Calcium oxalate (CaOx) crystal-induced kidney injury serves as the foundational mechanism for the formation and progression of CaOx stones. Regulated cell death (RCD) such as ferroptosis, necroptosis, and pyroptosis are essential in the pathophysiological process of kidney injury. Ferroptosis, a newly discovered RCD, is characterized by its reliance on iron-mediated lipid peroxidation. Necroptosis, a widely studied programmed necrosis, initiates with a necrotic phenotype that resembles apoptosis in appearance. Pyroptosis, a type of RCD that involves the gasdermin protein, is accompanied by inflammation and immune response. In recent years, increasing amounts of evidence has demonstrated that ferroptosis, necroptosis, and pyroptosis are significant pathophysiological processes involved in CaOx crystal-induced kidney injury. Herein, we summed up the roles of ferroptosis, necroptosis, and pyroptosis in CaOx crystal-induced kidney injury. Furthermore, we delved into the curative potential of ferroptosis, necroptosis, and pyroptosis in CaOx crystal-induced kidney injury.

Bioinformatics analysis and experimental validation of potential targets and pathways in chronic kidney disease associated with renal fibrosis

BACKGROUND

Chronic kidney disease (CKD) has emerged as a major health problem worldwide. Previous studies have shown that specific miRNA expression profiles of patients with CKD are significantly changed. In this study, we aim to elucidate the role of miRNAs as potential biomarkers in CKD progression by integrating bioinformatics analysis with experimental validation, thereby providing medical evidence for the prevention and treatment of CKD.

METHOD

Bioinformatics analysis was used to identify potential targets and pathways in CKD-associated renal fibrosis through randomly obtaining miRNA microarray data related to CKD patients in the Gene Expression Omnibus (GEO) database according to the inclusion and exclusion criteria, conducting pathway enrichment analysis and constructing protein-protein interaction (PPI) networks and miRNA-mRNA network by Cytoscape 3.8.0. In vitro experiments were employed to verify the role and mechanism of miR-223-3p in human renal tubular epithelial cells (HK2) through Quantitative real-time PCR assays, Western blot, Immunofluorescence analysis and Double luciferase reporter gene experiment. Multi-group one-way analysis of variance (ANOVA) and the Dunnett-t test were uesd to analyze the results by SPSS24.0.

RESULTS

10 up-regulated and 11 down-regulated miRNAs of CKD patients were screened out. Phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) was the first pathway of pathway enrichment analysis. MiR-223-3p (logFC=-2.047, p = 0.002) was one of the four hub miRNAs. Furthermore, we observed a reduction in α-smooth muscle actin (α-SMA) (p = 0.001) and Collagen type I alpha 1 (Col1-a1) (p = 0.023) levels upon miR-223-3p overexpression, which aligned with our bioinformatics predictions. This downregulation was attributed to the inhibition of nuclear factor kappa-B (NF-κB) nuclear translocation and subsequent decrease in the secretion of inflammatory cytokines, such as interleukin-6 (IL-6) (p = 0.005). Conversely, when CHUK was further overexpressed, the inhibitory effect of miR-223-3p on epithelial-mesenchymal transition (EMT) was attenuated, confirming the specific interaction between miR-223-3p and CHUK.

CONCLUSION

Our findings provide compelling evidence that miR-223-3p acts as a suppressor of EMT in CKD by specifically targeting the CHUK and modulating the PI3K/Akt pathway, which holds great promise as a novel therapeutic target for CKD treatment. Additionally, this study offers a potential avenue for the development of future interventions aimed at halting or reversing the progression of CKD.

Knocking-down annexin A3 suppresses inflammation, oxidative stress, apoptosis, and endoplasmic reticulum stress to attenuate sepsis-induced acute kidney injury in HK2 cells

Objective

Sepsis-induced acute kidney injury (AKI) is considered as a life-threatening complication of sepsis. The purpose of this study is to clarify the involvement of annexin A3 (ANXA3) in sepsis-related AKI.

Material and Methods

Lipopolysaccharide (LPS) was used to establish a cell model based on HK2 cells. ANXA3 expression was quantified through quantitative real-time polymerase chain reaction. Cell proliferative capacities were assessed through 5-ethynyl-2'-deoxyuridine proliferation, cell counting kit-8, and colony formation experiments. Flow cytometry was utilized to analyze apoptotic cells. Inflammatory and oxidative stress indicators were measured by employing corresponding commercial assay kits. Endoplasmic reticulum (ER) stress markers were quantified through western blot analysis.

Results

ANXA3 levels were significantly elevated in HK2 cells treated with LPS and in serum samples obtained from patients with AKI and sepsis (P < 0.001). LPS treatment exacerbated cellular damage, leading to increased ER and oxidative stresses, apoptosis, and inflammation, whereas knocking down ANXA3 significantly reversed these changes (P < 0.001).

Conclusion

Interference with ANXA3 protected HK2 cells from LPS-induced cell injury through inhibiting inflammation, oxidative stress, apoptosis, and ER stress.

Systematic review of microRNAs in human acute kidney injury

INTRODUCTION

Early diagnosis of acute kidney injury (AKI) is limited with current tools. MicroRNAs (miRNAs) are implicated in AKI pathogenesis in preclinical models, but less is known about their role in humans. We conducted a systematic review to identify dysregulated miRNAs in humans with AKI.

METHODS

We searched Ovid MEDLINE, Embase, Web of Science, and CENTRAL (August 21, 2023) for studies of human subjects with AKI. We excluded reviews and pre-clinical studies without human data. The primary outcome was dysregulated miRNAs in AKI. Two reviewers screened abstracts, reviewed full texts, performed data extraction and quality assessment (Newcastle Ottawa Scale).

RESULTS

We screened 2,456 reports and included 92 for synthesis without meta-analysis. All studies except one were observational. Studies were grouped by etiology of AKI: cardiac surgery-associated (CS-AKI, n = 13 studies), sepsis (n = 25), nephrotoxic (n = 9), kidney transplant (n = 26), and other causes (n = 19). In total, 128 miRNAs were identified to be dysregulated across AKI studies (45 miRNAs upregulated, 55 downregulated, 28 both). miR-21 was the most frequently reported (n = 17 studies) and it was increased in all etiologies except CS-AKI where it was decreased (n = 3 studies). Study limitations included bias due to targeted approaches, absence of clinical data/controls, and miRNA normalization methods. Overall study quality was fair (median 5/9, range 2-8 points).

CONCLUSION

Dysregulated miRNAs, particularly miR-21, have potential as AKI biomarkers. These results should be interpreted cautiously due to methodological limitations. Standardized methods and unbiased approaches are needed to validate candidate miRNA biomarkers.Registration: International Prospective Register of Systematic Reviews (PROSPERO CRD42020201253).

MiR-10b-5p attenuates spinal cord injury and alleviates LPS-induced PC12 cells injury by inhibiting TGF-β1 decay and activating TGF-β1/Smad3 pathway through PTBP1

Spinal cord injury (SCI) is a debilitating condition characterized by significant sensory, motor, and autonomic dysfunctions, leading to severe physical, psychological, and financial burdens. The current therapeutic approaches for SCI show limited effectiveness, highlighting the urgent need for innovative treatments. MicroRNAs (miRNAs) like miR-10b-5p are known to play pivotal roles in gene expression regulation and have been implicated in various neurodegenerative diseases, including SCI. Polypyrimidine tract binding protein 1 (PTBP1) has also been associated with neural injury responses and recovery. This study aims to explore the interaction between miR-10b-5p and PTBP1 in the context of SCI, hypothesizing that miR-10b-5p regulates PTBP1 to influence SCI pathogenesis and recovery using a rat model of SCI and lipopolysaccharide (LPS)-induced PC12 cells. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed to measure miR-10b-5p levels, revealing its low expression in SCI rats. We then assessed neurological function, histopathological changes, and spinal cord water content. We found that administering the agomiR-10b-5p significantly improved neurological function and decreased the spinal cord water content and normal motor neuron loss in SCI rats. Additionally, we explored the functions of miR-10b-5p in LPS-treated PC12 cells. Our results showed that miR-10b-5p repressed LPS-stimulated apoptosis, inflammation, and oxidative stress in PC12 cells. PTBP1 was predicted as a potential target gene of miR-10b-5p using the TargetScan database. Pulldown and luciferase reporter assays further demonstrated that miR-10b-5p binds to the 3' untranslated region (UTR) of PTBP1. RT-qPCR revealed that miR-10b-5p negatively modulated PTBP1 expression both in vivo and in vitro. Furthermore, rescue assays indicated that miR-10b-5p alleviated SCI in rats and LPS-triggered injury in PC12 cells by downregulating PTBP1. We also investigated the regulation of miR-10b-5p and PTBP1 on the transforming growth factor-beta 1 (TGF-β1)/small mother against decapentaplegic (Smad3) pathway. We found that miR-10b-5p targeted PTBP1 to repress TGF-β1 decay and facilitated TGF-β1/Smad3 pathway activation. In conclusion, our results demonstrate that miR-10b-5p alleviates SCI by repressing TGF-β1 decay and inducing TGF-β1/Smad3 pathway activation through PTBP1 downregulation. This study provides novel insights into potential targeted therapy plans for SCI.

MicroRNA-223 alleviates inflammatory response in renal ischemia-reperfusion injury by targeting NLRP3

We investigated the potential correlation between miR-223 and NAcHT, LRR, and PYd domain-containing protein 3 (NLRP3) in the context of renal ischemia-reperfusion injury (RIRI), which is a leading cause of acute renal failure with significant mortality rates. Additionally, miR-223 has been implicated in renal inflammation, further highlighting its relevance to this study. C57BL/6 male mice were used as RIRI models. After successful modeling, pathological examinations and serum creatinine and miR-223 levels were tested. Pro-inflammatory cytokine (IL-1β, IL-6, IL-8, NLPR3, TLR4) expression was detected in mice by western blot (kidney tissue) and enzyme-linked immunosorbent assay (serum). HK-2 cells were used for in vitro experiments. A hypoxia/reoxygenation (H/R) model was used, and miR-223 and pro-inflammatory cytokine levels were detected using PCR and western blot assays, respectively. A dual-luciferase reporter assay was conducted to confirm the binding of miR-223 to NLPR3. Next, NLRP3 was knocked down to determine whether the anti-inflammatory function of miR-223 is dependent on NLRP3. MiR-223 expression was lower in RIRI mice than in the sham operation group. The level of miR-223 negatively correlated with serum creatinine levels and the severity of tubule injury. Increased proinflammatory cytokine levels in RIRI mice were observed. In vitro, miR-223 alleviated the inflammatory response in H/R treated cells by inhibiting proinflammatory cytokines. Dual-luciferase reporter and western blot assays confirmed the binding of miR-223 to NLRP3. NLRP3 knockdown reversed the anti-inflammatory effects of miR-223 in HK-2 cells. MiR-223 plays an anti-inflammatory role in RIRI by targeting NLRP3 to repress pro-inflammatory factors.

Lipid nanoparticle-encapsulated lncRNA DLX6-AS1 knockdown ameliorates cerebral ischemic injury via the Nrf2/HO-1/NLRP3 axis

OBJECTIVE

Cerebral ischemia is a neurological disorder that leads to permanent disability. This research focuses on exploring the ameliorative effects of lipid nanoparticle (LNP)-encapsulated lncRNA DLX6-AS1 knockdown in cerebral ischemic injury via the Nrf2/HO-1/NLRP3 axis.

METHODS

LNP-encapsulated lncRNA DLX6-AS1 was prepared. Cerebral ischemic injury mouse models were established utilizing middle cerebral artery occlusion (MCAO). The mice were treated by intravenous injection of LNP-encapsulated lncRNA DLX6-AS1. The neurological deficits, Inflammatory factor levels, pathological characteristics were observed. In vitro N2a cell oxygen and glucose deprivation (OGD) models were established, and the cells were treated with LNP-encapsulated lncRNA DLX6-AS1 or Nrf2 inhibitor (ML385). Cell viability and apoptosis were tested. DLX6-AS1, Nrf2, HO-1, and NLRP3 expression levels were assessed.

RESULTS

LncRNA DLX6-AS1 levels were elevated in the brain tissues of mice with cerebral ischemic injury and OGD-induced N2a cells. LNP-encapsulated DLX6-AS1 siRNA (si-DLX6-AS1) improved neurological deficit scores, reduced the levels of inflammatory factors, improved brain tissue pathological damage, and raised the number of survival neurons in CA1. LNP-encapsulated si-DLX6-AS1 ameliorated the OGD-induced N2a cell viability decrease and apoptosis rate increase, and ML385 (Nrf2 inhibitor) reversed the ameliorative effects of LNP-encapsulated si-DLX6-AS1. In cerebral ischemic injury mice and OGD-induced N2a cells, Nrf2 and HO-1 levels were reduced and NLRP3 levels were increased. LNP-encapsulated si-DLX6-AS1 raised Nrf2 and HO-1 levels and reduced NLRP3 levels. Nrf2 inhibitor ML385 treatment reversed the ameliorative effects of LNP-encapsulated si-DLX6-AS1 on OGD-induced N2a cell viability and apoptosis.

CONCLUSION

Lipid nanoparticle-encapsulated si-DLX6-AS1 ameliorates cerebral ischemic injury via the Nrf2/HO-1/NLRP3 axis.

Neuroinflammation in Parkinson's disease: focus on the relationship between miRNAs and microglia

Parkinson's disease (PD) is a prevalent neurodegenerative disorder that affects the central nervous system (CNS). Neuroinflammation is a crucial factor in the pathological advancement of PD. PD is characterized by the presence of activated microglia and increased levels of proinflammatory factors, which play a crucial role in its pathology. During the immune response of PD, microglia regulation is significantly influenced by microRNA (miRNA). The excessive activation of microglia, persistent neuroinflammation, and abnormal polarization of macrophages in the brain can be attributed to the dysregulation of certain miRNAs. Additionally, there are miRNAs that possess the ability to inhibit neuroinflammation. miRNAs, which are small non-coding epigenetic regulators, have the ability to modulate microglial activity in both normal and abnormal conditions. They also have a significant impact on promoting communication between neurons and microglia.

Research Progress of Pyroptosis in Diabetic Kidney Disease

Pyroptosis, known as one typical mode of programmed cell death, is generally characterized by the cleaved gasdermin family (GSDMs) forming pores in the cell membrane and inducing cell rupture, and the activation of aspartate-specific proteases (caspases) has also been found during this process. Diabetic Kidney Disease (DKD) is caused by the complication of diabetes in the kidney, and the most important kidney's function, Glomerular Filtration Rate (GFR), happens to drop to less than 90% of its usual and even lead to kidney failure in severe cases. The persistent inflammatory state induced by high blood glucose implies the key pathology of DKD, and growing evidence shows that pyroptosis serves as a significant contributor to this chronic immune-mediated inflammatory disorder. Currently, the expanded discovery of GSDMs, pyroptosis, and its association with innate immunity has been more attractive, and overwhelming research is needed to sort out the implication of pyroptosis in DKD pathology. In this review, we comb both classical studies and newly founds on pyroptosis, prick off the novel awakening of pyroptosis in DKD, and center on the significance of pyroptosis in DKD treatment, aiming to provide new research targets and treatment strategies on DKD.

Pyroptosis: The Determinator of Cell Death and Fate in Acute Kidney Injury

Background

Acute kidney injury (AKI) is kidney damage that leads to a rapid decline in function. AKI primarily occurs when the tubular epithelium is damaged, causing swelling, loss of brush margin, and eventual apoptosis. Research has shown that tubular epithelial cell damage in AKI is linked to cell cycle arrest, autophagy, and regulation of cell death.

Summary

Pyroptosis, a type of programmed cell death triggered by inflammation, is believed to play a role in the pathophysiology of AKI. Cumulative evidence has shown that pyroptosis is the main cause of tubular cell death in AKI. Thus, targeted intervention of pyroptosis may be a promising therapeutic approach for AKI. This review delves deep into the cutting-edge research surrounding pyroptosis in the context of AKI, shedding light on its intricate mechanisms and potential implications for clinical practice. Additionally, we explore the exciting realm of potential preclinical treatment options for AKI, aiming to pave the way for future therapeutic advancements.

Key Messages

Pyroptosis, a highly regulated form of cell death, plays a crucial role in determining the fate of cells during the development of AKI. This intricate process involves the activation of inflammasomes, which are multi-protein complexes that initiate pyroptotic cell death. By understanding the mechanisms underlying pyroptosis, researchers aim to gain insights into the pathogenesis of AKI and potentially identify new therapeutic targets for this condition.

Long noncoding RNA: An emerging diagnostic and therapeutic target in kidney diseases

Long noncoding RNAs (lncRNAs) have critical roles in the development of many diseases including kidney disease. An increasing number of studies have shown that lncRNAs are involved in kidney development and that their dysregulation can result in distinct disease processes, including acute kidney injury, chronic kidney disease, and renal cell carcinoma. Understanding the roles of lncRNAs in kidney disease may provide new diagnostic and therapeutic opportunities in the clinic. This review provides an overview of lncRNA characteristics, and biological function and discusses specific studies that provide insight into the function and potential application of lncRNAs in kidney disease treatment.

Puerarin alleviates chronic renal failure-induced pyroptosis in renal tubular epithelial cells by targeting miR-342-3p/TGF-β/SMAD axis

BACKGROUND

Chronic renal failure (CRF) is the result of kidney damage. Puerarin is a flavonoid with specific nephroprotective effect, but its effect on CRF needs further research. This study explored the effect of puerarin on CRF and the potential molecular mechanism.

METHODS

Adenine was used to establish an in vivo CRF model in rats, and rats were intragastrically administered with puerarin at a dose of 400 mg/kg body weight once a day from day 1 to day 28. Hematoxylin and eosin (HE) and Masson staining were used to observe the morphology and fibrosis of kidney tissue. Lipopolysaccharide (LPS) (400 ng/mL)/H2O2 (200 µM) was applied to human kidney 2 (HK-2) cells to construct an in vitro CRF model. Enzyme-linked immunosorbent assay (ELISA) was performed to validate interleukin (IL)-1β and IL-18 levels. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) was performed to detect microRNA (miR)-342-3p levels. Transforming growth factor beta (TGF-β)1, SMAD2, SMAD3, and pyroptosis marker proteins were detected by Western blot. The interaction between miR-342-3p and TGF-β/SMAD was determined by a dual-luciferase reporter gene assay. Cell Counting Kit-8 (CCK-8) assay was utilized to determine cell viability.

RESULTS

In the CRF model, puerarin alleviated renal injury and fibrosis and reduced creatinine (Cr) and blood urea nitrogen (BUN) levels. At the same time, miR-342-3p was downregulated, while the TGF-β/SMAD axis was activated and levels of IL-1β and IL-18 were increased. After treatment of CRF rats with puerarin, the expression level of miR-342-3p was increased, the TGF-β/SMAD axis was inhibited, and the secretion of IL-1β and IL-18 was decreased. MiR-342-3p directly bound to and negatively regulated the expression of TGF-β1, SMAD2, and SMAD3. In the in vitro CRF model, miR-342-3p inhibited HK-2 cell pyroptosis by inhibiting the TGF-β/SMAD axis.

CONCLUSION

Puerarin reduced renal injury and pyroptosis in CRF rats by targeting the miR-342-3p/TGF-β/SMAD axis.

Study on identification of a three-microRNA panel in serum for diagnosing neonatal early onset sepsis

BACKGROUND

Comparing with other diseases, early onset sepsis (EOS) is a global health concern in neonatal period for its high morbidity and mortality rates. In recent years, many studies have contributed to the figure out the expression patterns of circulating micro-RNAs (miRNAs) in different diseases and progressions, which could function as diagnostic biomarkers for EOS. The purpose of this study was to analyze the expression patterns of selected miRNAs and evaluate their diagnostic value for early detection and treatment.

METHODS

This was a prospective cross-sectional study conducted from 1 July 2021 to 30 June 2022. We collected surplus peripheral blood and demographic statistics of septic neonates and non-infected neonates during the first 24 h after delivery and obtained 11 candidate miRNAs by literature screening. First, we extracted the candidate miRNAs from the serum of selected neonates and analyzed their expression levels, and then the receiver operating characteristic (ROC) curve was used to select the differentially expressed miRNAs. We analyzed their sensitivity and specificity and obtained the best diagnostic panel. Finally, with the help of differentially expressed miRNAs, we performed gene ontology (GO) enrichment and protein-protein interaction (PPI) analyses by their target genes.

RESULTS

In patients with EOS, three miRNAs (mir-223-3p, mir-15a-5p, and mir-17-5p) in serum were significantly downregulated, and mir-146a-5p, mir-1-3p, and mir-16-5p were upregulated. The diagnostic value of these miRNAs (miR-15a-5p, AUC = 0.67; miR-223-3p, AUC = 0.72; miR-16-5p, AUC = 0.68; miR-17-5p, AUC = 0.70; miR-1-3p, AUC = 0.69; miR-146a-5p, AUC = 0.72) was moderate, and the diagnostic panel constructed by miR-15a-5p, miR-223-3p, and miR-16-5p possessed a comparatively higher diagnostic value (AUC = 0.85, sensitivity: 74.6%, specificity: 86%), indicating that their combined application may be a promising biomarker for clinical diagnosis of EOS. According to GO enrichment analysis, most proteins encoded by target genes were located in the cytosol as for cellular component (CC), for molecular function (MF), most proteins acted as regulators in protein binding, and for biological process (BP). Most genes function in positive or negative regulation of transcription from RNA polymerase II promoter, and the top 10 hub genes were CDKN1A, YAP1, CCNE1, CCND1, CKK6, ERBB4, CHEK1, DICER1, VEGFA, and APP by rank degree after PPI construction.

CONCLUSIONS

The three-miRNA panels (miR-15a-5p, miR-223-3p, and miR-16-5p) may be a novel noninvasive biological marker for EOS screening.

The Role of Pyroptosis in the Pathogenesis of Kidney Diseases

BACKGROUND

Recently, in addition to apoptosis and necrosis, several other forms of cell death have been discovered, such as necroptosis, autophagy, pyroptosis, and ferroptosis. These cell death modalities play diverse roles in kidney diseases. Pyroptosis is a newly described type of proinflammatory programmed necrosis. Further exploring pyroptosis is helpful to slow the progression of kidney diseases and reduce their complications.

SUMMARY

Pyroptosis is mainly mediated by the cleavage of gasdermin D (GSDMD) along with downstream inflammasome activation. Activated caspase-1 induces the release of cytokines by cleaving GSDMD. Inflammation is a major pathogenic mechanism for kidney diseases. Increasing evidence corroborated that pyroptosis was closely related to the progression of renal diseases, including acute kidney injury, renal fibrosis, diabetic nephropathy, and kidney cancer. In this paper, we reviewed the role and the therapeutic treatment of pyroptosis in renal diseases.

KEY MESSAGES

The better understanding of the progress and new intervention approaches of pyroptosis in kidney diseases may pave the way for new therapeutic opportunities in clinical practice.

Roles of noncoding RNAs in septic acute kidney injury

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

The role of LncRNA-regulated autophagy in AKI

Acute kidney injury (AKI) is a complex clinical syndrome involving a series of pathophysiological processes regulated by multiple pathways at the molecular and cellular level. Long noncoding RNAs (lncRNAs) play an important role in the regulation of epigenetics, and their regulation of autophagy-related genes in AKI has attracted increasing attention. However, the role of lncRNA-regulated autophagy in AKI has not been fully elucidated. Evidence indicated that lncRNAs play regulatory roles in most factors that induce AKI. LncRNAs can regulate autophagy in AKI via a complex network of regulatory pathways to affect the development and prognosis of AKI. This article reviewed and analyzed the pathways of lncRNA regulation of autophagy in AKI in recent years. The results provide new ideas for further study of the pathophysiological process and targeted therapy for AKI.

Role of microRNAs in programmed cell death in renal diseases: A review

MicroRNAs (miRNAs) regulate gene expression involving kidney morphogenesis and cell proliferation, apoptosis, differentiation, migration, invasion, immune evasion, and extracellular matrix remodeling. Programmed cell death (PCD) is mediated and regulated by specific genes and a wealth of miRNAs, which participate in various pathological processes. Dysregulation of miRNAs can disrupt renal development and induce the onset and progression of various renal diseases. An in-depth understanding of how miRNAs regulate renal development and diseases is indispensable to comprehending how they can be used in new diagnostic and therapeutic approaches. However, the mechanisms are still insufficiently investigated. Hence, we review the current roles of miRNA-related signaling pathways and recent advances in PCD research and aim to display the potential crosstalk between miRNAs and PCD. The prospects of miRNAs as novel biomarkers and therapeutic targets are also described, which might provide some novel ideas for further studies.

Human bone marrow mesenchymal stem cell-derived extracellular vesicles reduce inflammation and pyroptosis in acute kidney injury via miR-223-3p/HDAC2/SNRK

OBJECTIVE

Bone marrow mesenchymal stem cell (BMSC)-derived extracellular vesicles (EVs) have been demonstrated as a potential therapeutic agent in acute kidney injury (AKI). However, little is known about the mechanisms of action of BMSC-derived EVs in AKI. Based on this, our research was designed to investigate the mechanism behind BMSC-derived EVs controlling inflammation and pyroptosis during AKI.

METHODS

Peripheral blood from AKI patients was used for detection of microRNA (miR)-223-3p, HDAC2, and SNRK expression. An AKI rat model was established, and HK-2 cell injury was induced by lipopolysaccharide (LPS) to establish a cellular model. Co-culture with BMSC-derived EVs and/or gain- and loss-of-function assays were conducted in LPS-treated HK-2 to evaluate the functions of BMSCs-EVs, miR-223-3p, HDAC2, and SNRK. AKI rats were simultaneously injected with EVs and short hairpin RNAs targeting SNRK. The interactions among miR-223-3p, HDAC2, and SNRK were evaluated by RIP, ChIP, and dual-luciferase gene reporter assays.

RESULTS

Patients with AKI had low miR-223-3p and SNRK expression and high HDAC2 expression in peripheral blood. Mechanistically, miR-223-3p targeted HDAC2 to accelerate SNRK transcription. In LPS-treated HK-2 cells, BMSCs-EVs overexpressing miR-223-3p increased cell viability and diminished cell apoptosis, KIM-1, LDH, IL-1β, IL-6, TNF-α, NLRP3, ASC, cleaved caspase-1, and IL-18 expression, and GSDMD cleavage, which was nullified by HDAC2 overexpression or SNRK silencing. In AKI rats, BMSCs-EV-shuttled miR-223-3p reduced CRE and BUN levels, apoptosis, inflammation, and pyroptosis, which was abrogated by SNRK silencing.

CONCLUSION

Conclusively, BMSC-derived EV-encapsulated miR-223-3p mitigated AKI-induced inflammation and pyroptosis by targeting HDAC2 and promoting SNRK transcription.

Caveolin-1 ameliorates acetaminophen-aggravated inflammatory damage and lipid deposition in non-alcoholic fatty liver disease via the ROS/TXNIP/NLRP3 pathway

The overuse of acetaminophen (APAP) may cause more severe hepatotoxicity in patients with non-alcoholic fatty liver disease (NAFLD). Caveolin-1 (CAV1), is an essential regulator of metabolic function, which can alleviate liver damage by scavenging reactive oxygen species (ROS). Evidence suggests that the NOD-like receptor family pyrin domain-containing 3 (NLRP3) -mediated pyroptosis is involved in the development of NAFLD. Moreover, thioredoxin-interactive protein (TXNIP) activation is a key event linking ROS to NLRP3 inflammasome. However, whether CAV1 alleviates APAP-aggravated hepatotoxicity in NAFLD via the ROS/TXNIP/NLRP3 pathway remains unclear. An in vivo fatty liver model was established by feeding mice a high-fat diet for 56 days. Additionally, using in vitro approach, AML-12 cells were incubated with free fatty acids for 48 h and APAP was added during the last 24 h. We found that the overuse of APAP in NAFLD not only induced oxidative stress, but also increased TXNIP expression, NLRP3-mediated pyroptosis, and lipid deposition. In addition to inhibiting ROS generation and lipid deposition, overexpression of CAV1 reduced the elevated levels of TXNIP expression and NLRP3-mediated pyroptosis. However, the effect of CAV1 on TXNIP expression, NLRP3-mediated pyroptosis, and lipid deposition was reversed by CAV1 small interfering RNA (siRNA) intervention. Finally, N-acetyl cysteine (NAC) treatment reduced CAV1 siRNA-mediated changes in TXNIP expression and NLRP3-mediated pyroptosis levels. These results demonstrate that the inhibitory effect of CAV1 on NLRP3-mediated pyroptosis may be mediated through the ROS/TXNIP axis. Moreover, the current study provides novel mechanistic insights into the protective effects of CAV1 on APAP-aggravated hepatotoxicity in NAFLD.

Polysaccharide of Atractylodes macrocephala Koidz alleviate lipopolysaccharide-stimulated liver inflammation injury of goslings through miR-223/NLRP3 axis

Lipopolysaccharide (LPS) infection could cause severe liver inflammation and lead to liver damage, even death. Previous studies have shown that polysaccharide of Atractylodes macrocephala Koidz (PAMK) could protect liver from inflammation caused by LPS in mice. However, whether PAMK could alleviate liver inflammatory injury in other animals with LPS is still unknown. For evaluating whether PAMK could alleviate liver inflammatory injury in goslings with LPS, a total of 80 healthy 1-day old Magang goslings were randomly divided into 4 groups (control group, PAMK group, LPS group, and PAMK+LPS group). Goslings in control group and LPS group were fed with basal diet, and goslings in PAMK group and PAMK+LPS group were fed basal diet supplemented with 400 mg/kg PAMK to the end of trial. On 24 d of age, goslings in the control group and PAMK group were intraperitoneal injected 0.5 mL normal saline, and goslings in LPS and PAMK+LPS groups were intraperitoneal injected with LPS at 5 mg/kg BW. The serum and liver samples were collected for further analysis after treatment of LPS at 6, 12, 24, and 48 h. Furthermore, the hepatocytes were extracted from goose embryo to measure the expression of the key genes of miR-223/NLRP3 axis. The results showed that PAMK pretreatment could maintain normal cell morphology of liver, alleviate the enhanced levels of biochemical indexes ALT and AST, decrease the levels of IL-1β and IL-18, increase the relative mRNA expression of miR-223, and decrease the expression of NLRP3, Caspase-1, and cleaved Caspase-1 in liver and hepatocytes of goslings induced by LPS. These results indicated that PAMK could relieve inflammatory liver tissue damage after LPS treatment and downregulate the level of inflammation factors via miR-223/NLRP3 axis, thus playing a liver protective role in liver inflammation injury in goslings.

Kidney diseases and long non-coding RNAs in the limelight

The most extensively and well-investigated sequences in the human genome are protein-coding genes, while large numbers of non-coding sequences exist in the human body and are even more diverse with more potential roles than coding sequences. With the unveiling of non-coding RNA research, long-stranded non-coding RNAs (lncRNAs), a class of transcripts &gt;200 nucleotides in length primarily expressed in the nucleus and rarely in the cytoplasm, have drawn our attention. LncRNAs are involved in various levels of gene regulatory processes, including but not limited to promoter activity, epigenetics, translation and transcription efficiency, and intracellular transport. They are also dysregulated in various pathophysiological processes, especially in diseases and cancers involving genomic imprinting. In recent years, numerous studies have linked lncRNAs to the pathophysiology of various kidney diseases. This review summarizes the molecular mechanisms involved in lncRNAs, their impact on kidney diseases, and associated complications, as well as the value of lncRNAs as emerging biomarkers for the prevention and prognosis of kidney diseases, suggesting their potential as new therapeutic tools.

miR-181a-5p Inhibits Pyroptosis in Sepsis-Induced Acute Kidney Injury through Downregulation of NEK7

Sepsis is a life-threatening organ dysfunction caused by the uncontrolled inflammation, easily affecting the kidney. Sepsis-induced acute kidney injury (S-AKI) has high morbidity and mortality, of which the pathophysiological mechanisms have not been completely illuminated, leading to nonspecific therapies. Specific microRNAs were related with the pathogenesis of AKI. However, only limited studies focused on the pyroptosis in the context of S-AKI. The in vitro LPS-induced HK-2 cell model and in vivo CLP-induced mouse model were established. qRT-PCR, Western blot, ELISA, and RNA pulldown were used for expression examination. Multiple biological databases were used for miRNA screening. H&E staining and IHC staining were performed. The LPS-induced HK-2 cells showed significantly increased (P < 0.01) fluorescence intensity of N-GSDMD and ASC compared with the HK-2 cells. The expression of NLRP3, NEK7, ASC, active caspase-1, and N-GSDMD was significantly enhanced (P < 0.05) and the inflammatory factors including IL-18, IL-1β, and THF-α were all increased in LPS-induced HK-2 cells and CLP-induced mice. Renal edema, serum Cr and BUN, and expression of KIM-1 and NGAL were significantly higher (P < 0.05) in CLP-induced S-AKI mice than the sham group. miR-101-3p, miR-144-3p, miR-181a-5p, miR-4262, and miR-513b-5p could inhibit NEK7. NEK7 is an interacting protein of miRNA-181a-5p. miR-181a-5p inhibits pyroptosis of the LPS-induced HK-2 cells through downregulation of NEK7. Pyroptosis of HK-2 cells promotes inflammation. miR-181a-5p inhibits pyroptosis through downregulation of NEK7 in LPS-induced HK-2 cells and CLP-induced mice. Our study indicated miR-181a-5p as a new potential therapeutic target for S-AKI therapy.

Molecular mechanisms and functions of pyroptosis in sepsis and sepsis-associated organ dysfunction

Sepsis, a life-threatening organ dysfunction caused by a dysregulated host response to infection, is a leading cause of death in intensive care units. The development of sepsis-associated organ dysfunction (SAOD) poses a threat to the survival of patients with sepsis. Unfortunately, the pathogenesis of sepsis and SAOD is complicated, multifactorial, and has not been completely clarified. Recently, numerous studies have demonstrated that pyroptosis, which is characterized by inflammasome and caspase activation and cell membrane pore formation, is involved in sepsis. Unlike apoptosis, pyroptosis is a pro-inflammatory form of programmed cell death that participates in the regulation of immunity and inflammation. Related studies have shown that in sepsis, moderate pyroptosis promotes the clearance of pathogens, whereas the excessive activation of pyroptosis leads to host immune response disorders and SAOD. Additionally, transcription factors, non-coding RNAs, epigenetic modifications and post-translational modifications can directly or indirectly regulate pyroptosis-related molecules. Pyroptosis also interacts with autophagy, apoptosis, NETosis, and necroptosis. This review summarizes the roles and regulatory mechanisms of pyroptosis in sepsis and SAOD. As our understanding of the functions of pyroptosis improves, the development of new diagnostic biomarkers and targeted therapies associated with pyroptosis to improve clinical outcomes appears promising in the future.

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

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

Strategies of LncRNA DLX6-AS1 on Study and Therapeutics

Accumulating evidence has revealed the vital regulatory roles of lncRNA DLX6-AS1 in various tumors at pre-transcriptional, transcriptional, and post-transcriptional levels, which makes it a potential prognosis factor and therapeutic target. In addition, the presence of lncRNA DLX6-AS1 in the exosomes of peripheral blood of patients with tumors may also contribute to it being a possible cancer-related biomarker. However, most literature studies are devoted to studying the effect of lncRNA DLX6-AS1 as a sponging molecule of miRNAs, the research of which is likely to get stuck into a dilemma. Literature studies published already have demonstrated an exciting cell malignant phenotype inhibition with the knockdown of lncRNA DLX6-AS1 in various tumor cell lines. With the comprehensive development of delivery systems, high-throughput sequencing, and aptamers, the problems of finding novel research methods and exploring the therapeutic options which are based on lncRNA DLX6-AS1 in vivo could come into a period to deal with. This review aims to summarize the research statuses of lncRNA DLX6-AS1, discuss other study methodologies and therapeutic strategies on it, which might be of help to the deep learning of lncRNA DLX6-AS1 and its application from basic to clinical research.

LncRNA DLX6-AS1 promotes microglial inflammatory response in Parkinson's disease by regulating the miR-223-3p/NRP1 axis

Parkinson's disease (PD) is a prevailing neurodegenerative disorder. This study discussed the mechanism of lncRNA distal-less homeobox 6 antisense 1 (DLX6-AS1) on inflammatory responses in PD. With healthy male C57BL/6 mice (8-10 weeks) and BV2 microglia as study subjects, we established PD models in vivo/in vitro by injection of 1-methyl-4-phenyl-2, 3, 6-tetrahydropyridine (MPTP) for 4 weeks and treatment of lipopolysaccharide (LPS) for 24hours, respectively. DLX6-AS1 expression in PD mice and BV2 microglia was examined using reverse transcription quantitative-polymerase chain reaction and then down-regulated via stereotaxic catheter injection or cell transfection to evaluate its effect on neurological function. Meanwhile, the cell number of TH+/Caspase3+/IBA1+ in substantia nigra, cell viability, and apoptosis rate of BV2 microglia, inflammatory levels, and NLR family pyrin domain containing 3 (NLRP3) inflammasome were determined using immunohistochemistry, MTT assay, flow cytometry, ELISA assay, and Western blot. The binding relationship between miR-223-3p and DLX6-AS1/Neuropilin-1 (NRP1) was verified by dual-luciferase assay and RNA immunoprecipitation assay. After down-regulation of DLX6-AS1, we down-regulated/overexpressed miR-223-3p/NRP1 levels in BV2 microglia. DLX6-AS1 was overexpressed in PD mice. Silencing DLX6-AS1 improved neurological function and alleviated microglial inflammation in PD mice. Specifically, the latency of mice falling from the rotating rod was longer, and the latency of climbing rod test was shorter; TH+ cells increased, while Caspase3+/IBA1+ cells decreased; the levels of inflammatory were lowered. Silencing DLX6-AS1 inhibited LPS-induced inflammation of BV2 microglia. DLX6-AS1 acted as the ceRNA of miR-223-3p to promote NRP1. Down-regulation of miR-223-3p or overexpression of NRP1 partially annulled the effect of silencing DLX6-AS1 on BV2 microglial inflammation. Overall, DLX6-AS1 promotes the microglial inflammatory response in PD through the ceRNA mechanism of miR-223-3p/NRP1.

Non-Coding RNAs in Sepsis-Associated Acute Kidney Injury

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

cAMP-response element binding protein mediates podocyte injury in diabetic nephropathy by targeting lncRNA DLX6-AS1

BACKGROUND

Progressive proteinuria is one of the earliest clinical features of diabetic nephropathy (DN). In our previous study, lncRNA DLX6-AS1 (DLX6-AS1, Dlx6os1 in the mouse) was found to be associated with the extent of albuminuria in DN patients. Furthermore, the lack of Dlx6os1 was pivotal in switching off the inflammatory response in db/db mouse model. However, the regulatory factors responsible for elevated DLX6-AS1 in DN remains unknown.

METHODS

To identify potential regulatory factors for DLX6-AS1, JASPAR database and DNA pull down combined subsequent liquid chromatography-tandem mass spectrometry were used. Dual-luciferase reporter assay and chromatin immunoprecipitation were then performed to confirm binding sites. We also investigated the effects of the regulatory factors on DN progression in db/db mouse model and cultured human podocytes.

RESULTS

Our analyses demonstrated that cAMP-response element binding protein (CREB) was highly expressed and closely associated with DLX6-AS1 in DN. In db/db mouse and in cultured podocytes, CREB silencing significantly reduced the level of DLX6-AS1 or Dlx6os1 and attenuated renal damage. Mechanistically, CREB overexpression aggravated renal inflammation and destroyed the structure of podocytes by targeting DLX6-AS1. The damaging role of CREB in podocyte injury was also inhibited by 666-15, a selective inhibitor, in a dose-dependent manner. In vivo, the inhibition of CREB by 666-15 significantly attenuated albuminuria and ameliorated inflammatory infiltration in podocytes.

CONCLUSIONS

Our findings indicated that CREB is a key mediator of podocyte injury and acts by regulating DLX6-AS1. Thus, CREB may be an effective and potential therapeutic target for the treatment of DN.

An Update of Long-Noncoding RNAs in Acute Kidney Injury

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

KLF6 Promotes Pyroptosis of Renal Tubular Epithelial Cells in Septic Acute Kidney Injury

ABSTRACT

Septic acute kidney injury (SAKI) represents a clinical challenge with high morbidity and mortality. The current study aimed to analyze the effects and molecular mechanism of Krüppel-like factor 6 (KLF6) on SAKI. First, SAKI mouse models were established by cecum ligation and puncture, while in vivo cell models were established using lipopolysaccharide (LPS). RT-qPCR assay was subsequently performed to detect the levels of KLF6 mRNA. SAKI mice and LPS-treated TCMK-1 cells were further treated with KLF6 siRNA. Afterward, HE staining, PAS staining, Western blot assay, and ELISA were adopted to ascertain the effects of KLF6 in pyroptosis. The binding relationships between KLF6 and miR-223-3p promoter /miR-223-3p and NLRP3 were analyzed with the help of CHIP and dual-luciferase reporter assays. RT-qPCR was adopted to determine the expression patterns of miR-223-3p and NLRP3. Lastly, a rescue experiment was designed to confirm the role of miR-223-3p. It was found that KLF6 was highly expressed in SAKI, whereas knockdown of KLF6 alleviated oxidative stress (OS) and pyroptosis in SAKI mice and LPS-treated TCMK-1 cells. Mechanistic results confirmed that KLF6 inhibited miR-223-3p via binding to the miR-223-3p promoter and promoted NLRP3. On the other hand, downregulation of miR-223-3p activated the NLRP3/Caspase-1/IL-1β pathway and aggravated OS and pyroptosis. Overall, our findings indicated that KLF6 inhibited miR-223-3p via binding to the miR-223-3p promoter and promoted NLRP3, and activated the NLRP3/Caspase-1/IL-1β pathway, thereby aggravating pyroptosis and SAKI.

Focus on the Mechanisms and Functions of Pyroptosis, Inflammasomes, and Inflammatory Caspases in Infectious Diseases

Eukaryotic cells can initiate several distinct self-destruction mechanisms to display essential roles for the homeostasis maintenance, development, and survival of an organism. Pyroptosis, a key response mode in innate immunity, also referred to as caspase-1-dependent proinflammatory programmed necrotic cell death activated by human caspase-1/4/5, or mouse caspase-1/11, plays indispensable roles in response to cytoplasmic insults and immune defense against infectious diseases. These inflammatory caspases are employed by the host to eliminate pathogen infections such as bacteria, viruses, protozoans, and fungi. Gasdermin D requires to be cleaved and activated by these inflammatory caspases to trigger the pyroptosis process. Physiological rupture of cells results in the release of proinflammatory cytokines, the alarmins IL-1β and IL-18, symbolizing the inflammatory potential of pyroptosis. Moreover, long noncoding RNAs play direct or indirect roles in the upstream of the pyroptosis trigger pathway. Here, we review in detail recently acquired insights into the central roles of inflammatory caspases, inflammasomes, and pyroptosis, as well as the crosstalk between pyroptosis and long noncoding RNAs in mediating infection immunity and pathogen clearance.

Long Noncoding RNA ZFAS1 Protects HK-2 Cells against Sepsis-Induced Injury through Targeting the miR3723p/PPARα Axis

In septic acute kidney injury, one of the main purposes of long noncoding RNA (lncRNA) ZFAS1 is still unclear. This study is intended to analyze the effects of lncRNA ZFAS1 on the septic AKI in the HK-2 cell line. Materials and Methods. In order to construct an in vitro model of septic AKI, HK-2 cells have been treated with lipopolysaccharides. CCK-8 assay has been utilized to check the viability of HK-2 cells. The contents of inflammatory cytokines (that includes IL-1β, TNF-α, and IL-6) have been marked with enzyme-linked immune sorbent assay (ELISA). Cell apoptosis was assessed by TUNEL staining. To detect the expression of lncRNA ZFAS1 and microRNA-372-3p, quantitative reverse-transcription PCR has been used. And to confirm the connection among genes, luciferase reporter assay has been applied. Results. Overexpression of ZFAS1 alleviated LPS-induced HK-2 cell injury. ZFAS1 positively regulated expression of α receptor activated by peroxisome proliferation (PPARα) through competitive linkage with miR-372-3p. In addition, over expression of miR-372-3p counteracted the protective effect of upward regulation of ZFAS1 on LPS-induced HK-2 cell damage, which could be reversed by over expression of PPARα. Conclusion. It is concluded that, in LPS-induced HK-2 cell injury, ZFAS1 has a protective role via modulating the miR-372-3p/PPARα axis, suggesting the potential of ZFAS1 as a protective target for septic AKI.

Regulatory Role of Non-Coding RNAs on Immune Responses During Sepsis

Sepsis is resulted from a systemic inflammatory response to bacterial, viral, or fungal agents. The induced inflammatory response by these microorganisms can lead to multiple organ system failure with devastating consequences. Recent studies have shown altered expressions of several non-coding RNAs such as long non-coding RNAs (lncRNAs), microRNAs (miRNAs) and circular RNAs (circRNAs) during sepsis. These transcripts have also been found to participate in the pathogenesis of multiple organ system failure through different mechanisms. NEAT1, MALAT1, THRIL, XIST, MIAT and TUG1 are among lncRNAs that participate in the pathoetiology of sepsis-related complications. miR-21, miR-155, miR-15a-5p, miR-494-3p, miR-218, miR-122, miR-208a-5p, miR-328 and miR-218 are examples of miRNAs participating in these complications. Finally, tens of circRNAs such as circC3P1, hsa_circRNA_104484, hsa_circRNA_104670 and circVMA21 and circ-PRKCI have been found to affect pathogenesis of sepsis. In the current review, we describe the role of these three classes of noncoding RNAs in the pathoetiology of sepsis-related complications.

The Programmed Cell Death of Macrophages, Endothelial Cells, and Tubular Epithelial Cells in Sepsis-AKI

Sepsis is a systemic inflammatory response syndrome caused by infection, following with acute injury to multiple organs. Sepsis-induced acute kidney injury (AKI) is currently recognized as one of the most severe complications related to sepsis. The pathophysiology of sepsis-AKI involves multiple cell types, including macrophages, vascular endothelial cells (ECs) and renal tubular epithelial cells (TECs), etc. More significantly, programmed cell death including apoptosis, necroptosis and pyroptosis could be triggered by sepsis in these types of cells, which enhances AKI progress. Moreover, the cross-talk and connections between these cells and cell death are critical for better understanding the pathophysiological basis of sepsis-AKI. Mitochondria dysfunction and oxidative stress are traditionally considered as the leading triggers of programmed cell death. Recent findings also highlight that autophagy, mitochondria quality control and epigenetic modification, which interact with programmed cell death, participate in the damage process in sepsis-AKI. The insightful understanding of the programmed cell death in sepsis-AKI could facilitate the development of effective treatment, as well as preventive methods.

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.

Roles and functions of antisense lncRNA in vascular aging

Vascular aging is a major cause of morbidity and mortality in the elderly population. Endothelial cells (ECs) and vascular smooth muscle cells (VSMCs), forming the intima and media layers of the vessel wall respectively, are closely associated with the process of vascular aging and vascular aging-related diseases. Numerous studies have revealed the pathophysiologic mechanism through which lncRNA contributes to vascular aging, hence more attention is now paid to the role played by antisense long non-coding RNA (AS-lncRNA) in the pathogenesis of vascular aging. Nonetheless, only a small number of studies focus on the specific mechanism through which AS-lncRNA mediates vascular aging. In this review, we summarize the roles and functions of AS-lncRNA with regards to the development of vascular aging and vascular aging-related disease. We also aim to deepen our understanding of this process and provide alternative therapeutic modalities for vascular aging-related diseases.

MicroRNA-223-3p is involved in fracture healing by regulating fibroblast growth factor receptor 2

MicroRNAs (miRNAs) are powerful modulators of fracture healing. The research explored the level of serum miR-223-3p in fracture patients and its potential mechanism in fracture healing. In the study, miR-223-3p levels in 42 patients with intra-articular fracture and 40 patients with hand fracture were detected by real-time fluorescence quantitative PCR reaction (qRT-PCR). Subsequently, osteoblasts MC3T3-E1 was transfected with miR-223-3p mimic or inhibitor, and cell function was detected by Cell counting kit (CCK-8) assay and flow cytometry. Dual-luciferase reporter assay verified the regulation mechanism of miR-223-3p and its target genes. We found that miR-223-3p was significantly elevated over time in patients with intra-articular fracture and hand fracture compared with healthy individuals. Moreover, increased miR-223-3p significantly reduced cell viability and promoted cell apoptosis. The fibroblast growth factor receptor 2 (FGFR2) was the target of miR-223-3p. Serum FGFR2 was significantly decreased in patients, which was contrary to the expression of miR-223-3p. Moreover, FGFR2 levels in cells were negatively regulated by miR-223-3p. Finally, si-FGFR2 significantly reversed the promotion of miR-223-3p inhibitor on cell viability and the inhibition of cell apoptosis. Our research suggested that miR-223-3p is highly expressed in fracture patients, and regulates osteoblast cell viability and apoptosis by targeting FGFR2. This may be a valuable target for fracture healing therapy and provide a new perspective for its treatment.

Non-Coding RNAs: Master Regulators of Inflammasomes in Inflammatory Diseases

Emerging data indicates that non-coding RNAs (ncRNAs) represent more than just “junk sequences” of the genome and have been found to be involved in multiple diseases by regulating various biological process, including the activation of inflammasomes. As an important aspect of innate immunity, inflammasomes are large immune multiprotein complexes that tightly regulate the production of pro-inflammatory cytokines and mediate pyroptosis; the activation of the inflammasomes is a vital biological process in inflammatory diseases. Recent studies have emphasized the function of ncRNAs in the fine control of inflammasomes activation either by directly targeting components of the inflammasomes or by controlling the activity of various factors that control the activation of inflammasomes; consequently, ncRNAs may represent potential therapeutic targets for inflammatory diseases. Understanding the precise role of ncRNAs in controlling the activation of inflammasomes will help us to design targeted therapies for multiple inflammatory diseases. In this review, we summarize the regulatory role and therapeutic potential of ncRNAs in the activation of inflammasomes by focusing on a range of inflammatory diseases, including microbial infection, sterile inflammatory diseases, and fibrosis-related diseases. Our goal is to provide new ideas and perspectives for future research.

lncRNA-SNHG14 Plays a Role in Acute Lung Injury Induced by Lipopolysaccharide through Regulating Autophagy via miR-223-3p/Foxo3a

lncRNAs play important roles in lipopolysaccharide- (LPS-) induced acute lung injury. But the mechanism still needs further research. In the present study, we investigate the functional role of the lncRNA-SNHG14/miR-223-3p/Foxo3a pathway in LPS-induced ALI and tried to confirm its regulatory effect on autophagy. Transcriptomic profile changes were identified by RNA-seq in LPS-treated alveolar type II epithelial cells. The expression changes of lncRNA-SNHG14/miR-223-3p/Foxo3a were confirmed using qRT-PCR and west blot. The binding relationship of lncRNA-SNHG14/miR-223-3p/and miR-223-3p/Foxo3a was verified using dual-luciferase reporter, RNA immunoprecipitation, and RNA pull-down assays. Using gain-of-function or loss-of-function approaches, the effect of lncRNA-SNHG14/miR-223-3p/Foxo3a was investigated in LPS-induced acute lung injury mice model and in vitro. Increasing of lncRNA-SNHG14 and Foxo3a with reducing miR-223-3p was found in LPS-treated A549 cells and lung tissue collected from the LPS-induced ALI model. lncRNA-SNHG14 inhibited miR-223-3p but promoted Foxo3a expression as a ceRNA. Artificially changes of lncRNA-SNHG14/miR-223-3p/Foxo3a pathway promoted or protected cell injury from LPS in vivo and in vitro. Autophagy activity could be influenced by lncRNA-SNHG14/miR-223-3p/Foxo3a pathway in cells with or without LPS treatment. In conclusion, aberrant expression changes of lncRNA-SNHG14 participated alveolar type II epithelial cell injury and acute lung injury induced by LPS through regulating autophagy. One underlying mechanism is that lncRNA-SNHG14 regulated autophagy by controlling miR-223-3p/Foxo3a as a ceRNA. It suggested that lncRNA-SNHG14 may serve as a potential therapeutic target for patients with sepsis-induced ALI.

Research progress of DLX6-AS1 in human cancers

Long non-coding RNAs (lncRNAs) are a kind of translational-repressor RNAs composed of more than 200 nucleotides and formerly considered as "transcriptional noise". Recently studies have shown that lncRNAs could bind to multiple biomolecules such as DNA, transcription factors, RNA, chromatin complexes and proteins, and regulate target gene expression at multi-levels, thus playing an essential role in human tumors. DLX6-AS1, a recently discovered oncogenic lncRNA, is highly expressed in various human tumors, including lung cancer, liver cancer and pancreatic cancer. This paper mainly reviewed the regulatory mechanism of DLX6-AS1 as a competitive endogenous RNA (ceRNA) in tumor cell proliferation, cell apoptosis, angiogenesis, epithelial-mesenchymal transformation, chemotherapy resistance and metabolic changes. Furthermore, the translational value of DLX6-AS1 in cancer was also elucidated, which suggested its potential as a diagnostic or prognostic biomarker in cancer. In summary, this present article not only makes an in-depth analysis of the expression changes and carcinogenic mechanism of DLX6-AS1 in various human cancers, but also provides a new breakthrough for the diagnosis and treatment of cancers.

Non-coding RNAs in necroptosis, pyroptosis and ferroptosis in cancer metastasis

Distant metastasis is the main cause of death for cancer patients. Recently, the newly discovered programmed cell death includes necroptosis, pyroptosis, and ferroptosis, which possesses an important role in the process of tumor metastasis. At the same time, it is widely reported that non-coding RNA precisely regulates programmed death and tumor metastasis. In the present review, we summarize the function and role of necroptosis, pyrolysis, and ferroptosis involving in cancer metastasis, as well as the regulatory factors, including non-coding RNAs, of necroptosis, pyroptosis, and ferroptosis in the process of tumor metastasis.

Long noncoding RNAs: A potential target in sepsis-induced cellular disorder

Sepsis, an inflammation-related clinical syndrome, is characterized by disrupted immune homeostasis accompanied by infection and multiple organ dysfunction as determined by the Sequential Organ Failure Assessment (SOFA). Substantial evidence has recently suggested that lncRNAs orchestrate various biological processes in diseases, and lncRNAs play special roles in the diagnosis and management of sepsis. To date, very few reviews have provided clear and comprehensive clues to demonstrate the roles of lncRNAs in the pathogenesis of sepsis. Based on previously published studies, in this review, we summarize the different functions of lncRNAs in sepsis-induced cellular disorders and sepsis-induced organ failure to show the potential roles of lncRNAs in the diagnosis and management of sepsis. We further depict the function of some lncRNAs known to be pivotal regulators in the pathogenesis of sepsis to discuss the underlying molecular events. Additionally, we list and discuss several hotspots in research on lncRNAs, which may be conducive to future lncRNA-targeted therapeutic approaches for sepsis treatment.

Non-Coding RNAs in Kidney Diseases: The Long and Short of Them

Recent progress in genomic research has highlighted the genome to be much more transcribed than expected. The formerly so-called junk DNA encodes a miscellaneous group of largely unknown RNA transcripts, which contain the long non-coding RNAs (lncRNAs) family. lncRNAs are instrumental in gene regulation. Moreover, understanding their biological roles in the physiopathology of many diseases, including renal, is a new challenge. lncRNAs regulate the effects of microRNAs (miRNA) on mRNA expression. Understanding the complex crosstalk between lncRNA–miRNA–mRNA is one of the main challenges of modern molecular biology. This review aims to summarize the role of lncRNA on kidney diseases, the molecular mechanisms involved, and their function as emerging prognostic biomarkers for both acute and chronic kidney diseases. Finally, we will also outline new therapeutic opportunities to diminish renal injury by targeting lncRNA with antisense oligonucleotides.

Long non-coding RNA SNHG14 aggravates LPS-induced acute kidney injury through regulating miR-495-3p/HIPK1

Acute kidney injury (AKI) is a complex syndrome with an abrupt decrease of kidney function, which is associated with high morbidity and mortality. Sepsis is the common cause of AKI. Mounting evidence has demonstrated that long non-coding RNAs (lncRNAs) play critical roles in the development and progression of sepsis-induced AKI. In this study, we aimed to illustrate the function and mechanism of lncRNA SNHG14 in lipopolysaccharide (LPS)-induced AKI. We found that SNHG14 was highly expressed in the plasma of sepsis patients with AKI. SNHG14 inhibited cell proliferation and autophagy and promoted cell apoptosis and inflammatory cytokine production in LPS-stimulated HK-2 cells. Functionally, SNHG14 acted as a competing endogenous RNA (ceRNA) to negatively regulate miR-495-3p expression in HK-2 cells. Furthermore, we identified that HIPK1 is a direct target of miR-495-3p in HK-2 cells. We also revealed that the SNHG14/miR-495-3p/HIPK1 interaction network regulated HK-2 cell proliferation, apoptosis, autophagy, and inflammatory cytokine production upon LPS stimulation. In addition, we demonstrated that the SNHG14/miR-495-3p/HIPK1 interaction network regulated the production of inflammatory cytokines (TNF-α, IL-6, and IL-1β) via modulating NF-κB/p65 signaling in LPS-challenged HK-2 cells. In conclusion, our findings suggested a novel therapeutic axis of SNHG14/miR-495-3p/HIPK1 to treat sepsis-induced AKI.

Peroxiredoxin 3 Inhibits Acetaminophen-Induced Liver Pyroptosis Through the Regulation of Mitochondrial ROS

Pyroptosis is a newly discovered form of cell death. Peroxiredoxin 3 (PRX3) plays a crucial role in scavenging reactive oxygen species (ROS), but its hepatoprotective capacity in acetaminophen (APAP)-induced liver disease remains unclear. The aim of this study was to assess the role of PRX3 in the regulation of pyroptosis during APAP-mediated hepatotoxicity. We demonstrated that pyroptosis occurs in APAP-induced liver injury accompanied by intense oxidative stress and inflammation, and liver specific PRX3 silencing aggravated the initiation of pyroptosis and liver injury after APAP intervention. Notably, excessive mitochondrial ROS (mtROS) was observed to trigger pyroptosis by activating the NLRP3 inflammasome, which was ameliorated by Mito-TEMPO treatment, indicating that the anti-pyroptotic role of PRX3 relies on its powerful ability to regulate mtROS. Overall, PRX3 regulates NLRP3-dependent pyroptosis in APAP-induced liver injury by targeting mitochondrial oxidative stress.

Ethyl Pyruvate Attenuates Microglial NLRP3 Inflammasome Activation via Inhibition of HMGB1/NF-κB/miR-223 Signaling

Ethyl pyruvate is a molecule with anti-inflammatory and pro-metabolic effects. Ethyl pyruvate has been shown to ameliorate the clinical and pathological findings of neurodegenerative diseases such as Alzheimer's and Parkinson's Diseases in rodents. Its anti-inflammatory and neuroprotective effects are widely investigated in animal and cellular models. Our study aimed to investigate the mechanism of the impact of Ethyl pyruvate on NLRP3 inflammasome activation in the N9 microglial cell line. Our results indicated that ethyl pyruvate significantly suppressed LPS and ATP-induced NLRP3 inflammasome activation, decreased active caspase-1 level, secretion of IL-1β and IL-18 cytokines, and reduced the level of pyroptotic cell death resulting from inflammasome activation. Furthermore, ethyl pyruvate reduced the formation of total and mitochondrial ROS and suppressed inflammasome-induced HMGB1 upregulation and nuclear NF-κB translocation and reversed the inflammasome activation-induced miRNA expression profile for miR-223 in N9 cells. Our study suggests that ethyl pyruvate effectively suppresses the NLRP3 inflammasome activation in microglial cells regulation by miR-223 and NF-κB/HMGB1 axis.

LncRNA NKILA knockdown promotes cell viability and represses cell apoptosis, autophagy and inflammation in lipopolysaccharide-induced sepsis model by regulating miR-140-5p/CLDN2 axis

BACKGROUND

Long non-coding RNAs (lncRNAs) play vital roles in human diseases, including sepsis-induced acute kidney injury (AKI). Here, we aimed to investigate the functions of lncRNA NKILA in sepsis-engendered AKI.

METHODS

HK2 cells stimulated with LPS were used to mimic sepsis-induced AKI in vitro. qRT-PCR was conducted for lncRNA NKILA and miR-140-5p levels. Cell Counting Kit-8 (CCK-8) assay and flow cytometry analysis were employed to analyze cell viability and apoptosis. Western blot assay was utilized to measured protein levels. ELISA kits were used to examine the concentrations of IL-6, IL-1β and TNF-α. Dual-luciferase reporter assay was utilized to analyze the relationships among lncRNA NKILA, miR-140-5p and claudin 2 (CLDN2).

RESULTS

LPS restrained HK2 cell viability and accelerated cell apoptosis and autophagy. LncRNA NKILA was increased in LPS-treated HK2 cells. LncRNA NKILA silencing reversed the promotional influence of LPS on cell progression in HK2 cells. miR-140-5p inhibition ameliorated lncRNA NKILA knockdown-mediated cell injury in LPS-mediated HK2 cells. CLDN2 was the target of miR-140-5p. MiR-140-5p elevation promoted cell viability and suppressed cell apoptosis, autophagy and inflammation in LPS-induced HK2 cells, with CLDN2 elevation overturned the effects.

CONCLUSION

LncRNA NKILA silencing protected HK2 cells from LPS-induced impairments by reducing CLDN2 through sponging miR-140-5p.

Long non-coding RNA NEAT1 promotes lipopolysaccharide-induced injury in human tubule epithelial cells by regulating miR-93-5p/TXNIP axis

Many long non-coding RNAs (lncRNAs) have been found to play crucial roles in sepsis-induced acute kidney injury (AKI), including lncRNA nuclear-enriched abundant transcript 1 (NEAT1). We aimed to further elucidate the functions and molecular mechanism of NEAT1 in sepsis-induced AKI. Sepsis-induced AKI cell model was established by treatment with lipopolysaccharide (LPS) in human tubule epithelial (HK2) cells. Cell viability and apoptosis were determined by Cell Counting Kit-8 (CCK-8) assay and flow cytometry, respectively. Western blot assay was performed to measure all protein levels. The concentrations of inflammatory factors were evaluated using enzyme-linked immunosorbent assay (ELISA). The expression levels of inflammatory factors, NEAT1, microRNA-93-5p (miR-93-5p), and thioredoxin-interacting protein (TXNIP) were measured by quantitative real-time polymerase chain reaction (qRT-PCR). The oxidative stress factors were detected using corresponding kits. The interaction between miR-93-5p and NEAT1 or TXNIP was predicted by bioinformatics analysis and verified by dual-luciferase reporter and RNA Immunoprecipitation (RIP) assays. NEAT1 was upregulated in serum of sepsis patients and LPS-induced HK2 cells. NEAT1 silence alleviated LPS-induced HK2 cell injury by inhibiting apoptosis, inflammation and oxidative stress. Moreover, miR-93-5p was a direct target of NEAT1, and suppression of NEAT1 weakened LPS-induced injury by upregulating miR-93-5p in HK2 cells. Furthermore, TXNIP was a downstream target of miR-93-5p, and miR-93-5p attenuated LPS-induced HK2 cell injury by downregulating TXNIP. In addition, NEAT1 regulated TXNIP expression by acting as a sponge of miR-93-5p. NEAT1 might aggravate LPS-induced injury in HK2 cells by regulating miR-93-5p/TXNIP axis, providing a potential therapeutic strategy for sepsis-associated AKI.

Bioinformatic analysis identifies potential biomarkers and therapeutic targets of septic-shock-associated acute kidney injury

Background

Sepsis and septic shock are life-threatening diseases with high mortality rate in intensive care unit (ICU). Acute kidney injury (AKI) is a common complication of sepsis, and its occurrence is a poor prognostic sign to septic patients. We analyzed co-differentially expressed genes (co-DEGs) to explore relationships between septic shock and AKI and reveal potential biomarkers and therapeutic targets of septic-shock-associated AKI (SSAKI).

Methods

Two gene expression datasets (GSE30718 and GSE57065) were downloaded from the Gene Expression Omnibus (GEO). The GSE57065 dataset included 28 septic shock patients and 25 healthy volunteers and blood samples were collected within 0.5, 24 and 48 h after shock. Specimens of GSE30718 were collected from 26 patients with AKI and 11 control patents. AKI-DEGs and septic-shock-DEGs were identified using the two datasets. Subsequently, Gene Ontology (GO) functional analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, and protein-protein interaction (PPI) network analysis were performed to elucidate molecular mechanisms of DEGs. We also evaluated co-DEGs and corresponding predicted miRNAs involved in septic shock and AKI.

Results

We identified 62 DEGs in AKI specimens and 888, 870, and 717 DEGs in septic shock blood samples within 0.5, 24 and 48 h, respectively. The hub genes of EGF and OLFM4 may be involved in AKI and QPCT, CKAP4, PRKCQ, PLAC8, PRC1, BCL9L, ATP11B, KLHL2, LDLRAP1, NDUFAF1, IFIT2, CSF1R, HGF, NRN1, GZMB, and STAT4 may be associated with septic shock. Besides, co-DEGs of VMP1, SLPI, PTX3, TIMP1, OLFM4, LCN2, and S100A9 coupled with corresponding predicted miRNAs, especially miR-29b-3p, miR-152-3p, and miR-223-3p may be regarded as promising targets for the diagnosis and treatment of SSAKI in the future.

Conclusions

Septic shock and AKI are related and VMP1, SLPI, PTX3, TIMP1, OLFM4, LCN2, and S100A9 genes are significantly associated with novel biomarkers involved in the occurrence and development of SSAKI.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41065-021-00176-y.