CircVMA21 ameliorates lipopolysaccharide (LPS)-induced HK-2 cell injury depending on the regulation of miR-7-5p/PPARA

CircNRIP1 promotes proliferation, migration and phenotypic switch of Ang II-induced HA-VSMCs by increasing CXCL5 mRNA stability via recruiting IGF2BP1

Circular RNA (circRNA) has been found to be differentially expressed and involved in regulating the processes of human diseases, including thoracic aortic dissection (TAD). However, the role and mechanism of circNRIP1 in the TAD process are still unclear. GEO database was used to screen the differentially expressed circRNA and mRNA in type A TAD patients and age-matched normal donors. Angiotensin II (Ang II)-induced human aortic vascular smooth muscle cells (HA-VSMCs) were used to construct TAD cell models. The expression levels of circNRIP1, NRIP1, CXC-motif chemokine 5 (CXCL5) and IGF2BP1 were detected by quantitative real-time PCR. Cell proliferation and migration were determined by EdU assay, transwell assay and wound healing assay. The protein levels of synthetic phenotype markers, contractile phenotype markers, CXCL5 and IGF2BP1 were tested by western blot analysis. The interaction between IGF2BP1 and circNRIP1/CXCL5 was confirmed by RIP assay, and CXCL5 mRNA stability was assessed by actinomycin D assay. CircNRIP1 was upregulated in TAD patients and Ang II-induced HA-VSMCs. Knockdown of circNRIP1 suppressed Ang II-induced proliferation, migration and phenotypic switch of HA-VSMCs. Also, high expression of CXCL5 was observed in TAD patients, and its knockdown could inhibit Ang II-induced HA-VSMCs proliferation, migration and phenotypic switch. Moreover, CXCL5 overexpression reversed the regulation of circNRIP1 knockdown on Ang II-induced HA-VSMCs functions. Mechanistically, circNRIP1 could competitively bind to IGF2BP1 and subsequently enhance CXCL5 mRNA stability. CircNRIP1 might contribute to TAD progression by promoting CXCL5 mRNA stability via recruiting IGF2BP1.

PPARA ameliorates sepsis-induced myocardial injury via promoting macrophage M2 polarization by interacting with DUSP1

Background

The morbidity and mortality of sepsis are increasing year by year. Statistically, 40-50% of patients with sepsis have concomitant myocardial injury, and its mortality rate is higher than that of patients with sepsis only. Therefore, it is of great significance to elucidate the mechanism of sepsis-induced myocardial injury.

Methods and results

Human monocytes (THP-1) were used to induce M0 macrophages, followed by treated with lipopolysaccharide (LPS). Cardiomyocytes (AC16) were co-cultured with the conditioned medium of LPS-induced macrophages to induce injury. Quantitative real-time PCR was employed to detect the mRNA levels of peroxisome proliferator-activated receptor α (PPARA) and dual specificity phosphatase 1 (DUSP1). Protein levels of PPARA, macrophage polarization-related markers, apoptosis-related markers, mitochondria-related proteins, and DUSP1 were analyzed by Western blot. Flow cytometry was used to assess M1/M2 cell rates and apoptosis. Low PPARA expression could serve as a biomarker for patients with sepsis. PPARA overexpression enhanced M2 polarization and suppressed M1 polarization in LPS-induced macrophages, and it could alleviate cardiomyocyte injury in co-cultured system. PPARA bound to the DUSP1 promoter region and facilitated its expression. DUSP1 knockdown reversed the effect of PPARA overexpression on M2 polarization and cardiomyocyte injury.

Conclusion

PPARA attenuated cardiomyocyte injury by promoting macrophage M2 polarization through increasing DUSP1 expression, suggesting that PPARA might be a therapy target for sepsis-induced myocardial injury.

MicroR-380-3p Reduces Sepsis-Induced Acute Kidney Injury via Regulating RAB1P to Restrain NF-κB Pathway

Septic acute kidney injury (AKI) is a common complication in critically ill patients with high morbidity and mortality. This study intends to clarify the clinical value and molecular mechanism of microR-380-3p in septic AKI by recruiting patients with septic AKI and establishing septic AKI cell models. Patients with septic AKI were included and human kidney-2 (HK-2) cells were induced by lipopolysaccharide (LPS) to construct the AKI cell model of sepsis. The expression of microR-380-3p was detected by quantitative real-time RT-PCR (qRT-PCR). The expression of Bax, cleaved caspase 3, Bcl-2, p65, and p-p65 was detected by Western blot. The contents of inflammation and oxidation were determined by commercial kits. Bioinformatics predicted the binding target of microR-380-3p and a dual luciferase reporting system was used to verify the regulatory relationship between microR-380-3p and RAP1B. The concentration of microR-380-3p was elevated in patients with septic AKI and appeared to be a biomarker for these patients. Silenced microR-380-3p reversed the damage of LPS on HK-2 cells via promoting viability, inhibiting apoptosis, inflammation, and oxidation. RAP1B was a target of microR-380-3p and microR-380-3p exerted targeted inhibition of RAP1B expression level. Down-regulation of RAP1B reversed the influence of silenced microR-380-3p on HK-2 cells. MicroR-380-3p/RAP1B participated in activating the NF-κB pathway. MicroR-380-3p down-regulated RAP1B to exacerbate septic AKI, providing a potential therapeutic biomarker for septic AKI.

Potential therapeutic applications of circular RNA in acute kidney injury

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

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

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

Study of the Anti-Inflammatory Mechanism of β-Carotene Based on Network Pharmacology

β-carotene is known to have pharmacological effects such as anti-inflammatory, antioxidant, and anti-tumor properties. However, its main mechanism and related signaling pathways in the treatment of inflammation are still unclear. In this study, component target prediction was performed by using literature retrieval and the SwissTargetPrediction database. Disease targets were collected from various databases, including DisGeNET, OMIM, Drug Bank, and GeneCards. A protein-protein interaction (PPI) network was constructed, and enrichment analysis of gene ontology and biological pathways was carried out for important targets. The analysis showed that there were 191 unique targets of β-carotene after removing repeat sites. A total of 2067 targets from the three databases were integrated, 58 duplicate targets were removed, and 2009 potential disease action targets were obtained. Biological function enrichment analysis revealed 284 biological process (BP) entries, 31 cellular component (CC) entries, 55 molecular function (MF) entries, and 84 cellular pathways. The biological processes were mostly associated with various pathways and their regulation, whereas the cell components were mainly membrane components. The main molecular functions included RNA polymerase II transcription factor activity, DNA binding specific to the ligand activation sequence, DNA binding, steroid binding sequence-specific DNA binding, enzyme binding, and steroid hormone receptors. The pathways involved in the process included the TNF signaling pathway, sphingomyelin signaling pathway, and some disease pathways. Lastly, the anti-inflammatory signaling pathway of β-carotene was systematically analyzed using network pharmacology, while the molecular mechanism of β-carotene was further explored by molecular docking. In this study, the anti-inflammatory mechanism of β-carotene was preliminarily explored and predicted by bioinformatics methods, and further experiments will be designed to verify and confirm the predicted results, in order to finally reveal the anti-inflammatory mechanism of β-carotene.

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.

EXOSOMAL CIRCVMA21 DERIVED FROM ADIPOSE-DERIVED STEM CELLS ALLEVIATES SEPSIS-INDUCED ACUTE KIDNEY INJURY BY TARGETING MIR-16-5P

ABSTRACT

Background: Exosome from adipose-derived stem cells (ADSCs-Exo) has been shown to inhibit the progression of human diseases, including sepsis-related acute kidney injury (AKI). CircVMA21 is considered to be an important regulator for sepsis-related AKI. However, whether ADSCs-Exo affected sepsis-induced AKI by delivering circVMA21 is not clear. Methods: Adipose-derived stem cells were identified by alizarin red staining, oil red O staining, and flow cytometry. Exosome from adipose-derived stem cells was authenticated by transmission electron microscopy, nanoparticle tracking analysis, western blot analysis, and immunofluorescence assay. Cell apoptosis was assessed by flow cytometry, and inflammation cytokine levels were determined by ELISA. Lactate production was assessed using Lactate Acid Content Assay Kit. The expression levels of aerobic glycolysis-related markers, circVMA21 and miR-16-5p, was evaluated by quantitative real time-polymerase chain reaction. Dual-luciferase reporter assay and RIP assay were employed to detect RNA interaction. Animal experiments were used to evaluate the role of ADSCs-Exo on renal function and cell injury in LPS-induced AKI mice model. Results: Exosome from adipose-derived stem cells inhibited LPS-induced HK-2 cell apoptosis, inflammation, and aerobic glycolysis. Knockdown of exosomal circVMA21 derived from ADSCs enhanced HK-2 cell injury induced by LPS. In terms of mechanism, circVMA21 could serve as sponge for miR-16-5p. Besides, miR-16-5p inhibitor reversed the promotion effect of Exo-sh-circVMA21 on LPS-induced cell injury. In addition, ADSCs-Exo protected LPS-induced AKI in mice by increasing circVMA21 expression and decreasing miR-16-5p expression. Conclusion: Exosomal circVMA21 derived by ADSCs relieved LPS-induced AKI through targeting miR-16-5p, which provided a potential molecular target for treating sepsis-related AKI.

MicroRNA-7: A New Intervention Target for Inflammation and Related Diseases

MicroRNAs (miRNAs) are a class of small noncoding RNA that can regulate physiological and pathological processes through post-transcriptional regulatory gene expression. As an important member of the miRNAs family, microRNA-7 (miR-7) was first discovered in 2001 to play an important regulatory role in tissue and organ development. Studies have shown that miR-7 participates in various tissue and organ development processes, tumorigenesis, aging, and other processes by regulating different target molecules. Notably, a series of recent studies have determined that miR-7 plays a key regulatory role in the occurrence of inflammation and related diseases. In particular, miR-7 can affect the immune response of the body by influencing T cell activation, macrophage function, dendritic cell (DC) maturation, inflammatory body activation, and other mechanisms, which has important potential application value in the intervention of related diseases. This article reviews the current regulatory role of miR-7 in inflammation and related diseases, including viral infection, autoimmune hepatitis, inflammatory bowel disease, and encephalitis. It expounds on the molecular mechanism by which miR-7 regulates the occurrence of inflammatory diseases. Finally, the existing problems and future development directions of miR-7-based intervention on inflammation and related diseases are discussed to provide new references and help strengthen the understanding of the pathogenesis of inflammation and related diseases, as well as the development of new strategies for clinical intervention.

Capturing the Kidney Transcriptome by Urinary Extracellular Vesicles-From Pre-Analytical Obstacles to Biomarker Research

Urinary extracellular vesicles (uEV) hold non-invasive RNA biomarkers for genitourinary tract diseases. However, missing knowledge about reference genes and effects of preanalytical choices hinder biomarker studies. We aimed to assess how preanalytical variables (urine storage temperature, isolation workflow) affect diabetic kidney disease (DKD)-linked miRNAs or kidney-linked miRNAs and mRNAs (kidney-RNAs) in uEV isolates and to discover stable reference mRNAs across diverse uEV datasets. We studied nine raw and normalized sequencing datasets including healthy controls and individuals with prostate cancer or type 1 diabetes with or without albuminuria. We focused on kidney-RNAs reviewing literature for DKD-linked miRNAs from kidney tissue, cell culture and uEV/urine experiments. RNAs were analyzed by expression heatmaps, hierarchical clustering and selecting stable mRNAs with normalized counts (>200) and minimal coefficient of variation. Kidney-RNAs were decreased after urine storage at -20 °C vs. -80 °C. Isolation workflows captured kidney-RNAs with different efficiencies. Ultracentrifugation captured DKD -linked miRNAs that separated healthy and diabetic macroalbuminuria groups. Eleven mRNAs were stably expressed across the datasets. Hence, pre-analytical choices had variable effects on kidney-RNAs-analyzing kidney-RNAs complemented global correlation, which could fade differences in some relevant RNAs. Replicating prior DKD-marker results and discovery of candidate reference mRNAs encourages further uEV biomarker studies.

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

ABSTRACT

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

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.