SIS3 Alleviates Cisplatin-Induced Acute Kidney Injury by Regulating the LncRNA Arid2-IR-Transferrin Receptor Pathway.

INTRODUCTION: TGF-ß/Smad3 may be involved in the pathogenesis of acute kidney injury (AKI), but its functional role and mechanism of action in cisplatin-induced AKI are unclear. Here, we established a cisplatin-induced AKI mouse model to demonstrate that Smad3 may have roles in cisplatin nephropathy because of its potential effects on tubular epithelial cell (TEC) death and regeneration. METHODS: Using a cisplatin-induced AKI model, the expression levels of lncRNA Arid2-IR were measured by qRT-PCR and the location detected by FISH. Transfected with overexpression of lncRNA Arid2-IR by lentiviral vector in TECs, and the expression of cleaved caspase 3, Bax, Bcl-2, PCNA, p21, p27, transferrin receptor (TFRC), FTH, and FTL were measured by Western blot. Protein molecules bound to lncRNA Arid2-IR were identified by RIP, RNA pull-down assay, mass spectrometry. RESULTS: LncRNA Arid2-IR was significantly downregulated in vivo and in vitro. SIS3 decreased cell apoptosis and promoted cell regeneration by upregulating lncRNA Arid2-IR expression. LncRNA Arid2-IR regulated the cell cycle by decreasing expression of the cyclin-dependent kinase inhibitors p21 and p27. Finally, lncRNA Arid2-IR interacted with the TFRC, and overexpression of lncRNA Arid2-IR increased TFRC expression and decreased FTH and FTL. CONCLUSION: Smad3 regulated lncRNA Arid2-IR via TFRC, thereby regulating the cell cycle, protecting against cell apoptosis, and promoting cell regeneration.

Arid2-IR promotes NF-κB-mediated renal inflammation by targeting NLRC5 transcription.

Increasing evidence shows that long non-coding RNAs (lncRNAs) play an important role in a variety of disorders including kidney diseases. It is well recognized that inflammation is the initial step of kidney injury and is largely mediated by nuclear factor Kappa B (NF-κB) signaling. We had previously identified lncRNA-Arid2-IR is an inflammatory lncRNA associated with NF-κB-mediated renal injury. In this study, we examined the regulatory mechanism through which Arid2-IR activates NF-κB signaling. We found that Arid2-IR was differentially expressed in response to various kidney injuries and was induced by transforming growth factor beta 1(TGF-ß1). Using RNA sequencing and luciferase assays, we found that Arid2-IR regulated the activity of NF-κB signal via NLRC5-dependent mechanism. Arid2-IR masked the promoter motifs of NLRC5 to inhibit its transcription. In addition, during inflammatory response, Filamin A (Flna) was increased and functioned to trap Arid2-IR in cytoplasm, thereby preventing its nuclear translocation and inhibition of NLRC5 transcription. Thus, lncRNA Arid2-IR mediates NF-κB-driven renal inflammation via a NLRC5-dependent mechanism and targeting Arid2-IR may be a novel therapeutic strategy for inflammatory diseases in general.

Arid2-IR downregulates miR-132-3p through methylation to promote LPS-induced ALI in pneumonia.

OBJECTIVE: Arid2-IR is a long non-coding RNA (lncRNA) that promotes renal injury, while its role in lipopolysaccharides (LPS)-induced acute lung injury (ALI) is unknown. Our preliminary sequencing analysis revealed an inverse correlation of Arid2-IR and miR-132-3p, which is known to suppress LPS-induced ALI. Therefore, Arid2-IR and miR-132-3p may interact with each other to participate in LPS-induced ALI in pneumonia. This study aimed to investigate the interaction between Arid2-IR and miR-132-3p in ALI induced by pneumonia. MATERIALS AND METHODS: Plasma samples were obtained from patients with pneumonia (n = 98) and healthy controls (n = 98) to detect the expression of circulating Arid2-IR and miR-132-3p. The correlation between them was analyzed using Pearson's correlation coefficient. The crosstalk between them in human bronchial epithelial cells (HBEpC) was analyzed through overexpression assay. MSP was applied to determine the methylation of the miR-132-3p gene. Cell viability was evaluated by 2,5-diphenyl-2H-tetrazolium bromide assay. RESULTS: Arid2-IR was highly upregulated in pneumonia group, while the expression levels of miR-132-3p decreased in pneumonia group compared to that in the controls. Arid2-IR and miR-132-3p were inversely correlated across patient samples. Overexpression of Arid2-IR decreased the expression levels of miR-132-3p in HBEpCs and increased the methylation of miR-132-3p gene. Arid2-IR suppressed the role of miR-132-3p in increasing the viability of HBEpCs induced by LPS. DISCUSSION AND CONCLUSION: Arid2-IR is upregulated in pneumonia and may downregulate miR-132-3p by increasing its methylation to decrease cell viability, thereby promoting LPS-induced ALI in pneumonia.

Long non-coding RNA Arid2-IR affects advanced glycation end products-induced human retinal endothelial cell injury by binding to Smad3.

PURPOSE: Long non-coding RNAs (lncRNAs) have been reported to play significant roles in the pathogenesis of diabetic retinopathy (DR). The aim of the present study was to investigate the role of lncRNA Arid2-IR in advanced glycation end product (AGE)-induced human retinal endothelial cells (HRECs) injury. MATERIALS AND METHODS: Cell viability was determined by Cell Counting Kit-8 assay following induction with AGEs. The expression of Arid2-IR and Smad3 was detected by reverse transcription-quantitative PCR or western blotting. A luciferase reporter assay was conducted to determine the interaction between Arid2-IR and Smad3. The levels of inflammation-related and oxidative stress-related factors were evaluated by respective kits. The expression of extracellular matrix (ECM)-related and apoptosis-related proteins was detected by western blotting. Immunofluorescence assay was used to detect the level of vascular endothelial growth factor, and flow cytometry was applied to measure the levels of apoptosis. RESULTS: The results revealed that AGE treatment decreased HREC proliferation and upregulated the expression of Arid2-IR and Smad3. The luciferase assay indicated that Smad3 was able to bind to the promoter region sequence of Arid2-IR. Moreover, Arid2-IR silencing reduced inflammation, oxidative stress and ECM production induced by AGEs in HRECs, and Smad3 inhibition further reduced the levels of the aforementioned factors, while Smad3 overexpression exerted the opposite effect. Furthermore, apoptosis of HRECs induced by AGEs was decreased following Arid2-IR silencing, which was further reduced following treatment with Smad3 inhibitor, but was reversed after transfection with Smad3 pcDNA3.1. CONCLUSION: The findings demonstrated that Arid2-IR affects AGE-induced HREC injury by binding to Smad3.