Circ_0091702 serves as a sponge of miR-545-3p to attenuate sepsis-related acute kidney injury by upregulating THBS2.

Circular RNA (circRNA) has been shown to play an important function in the progression of human diseases, including sepsis with acute kidney injury (AKI). However, the role and mechanism of circ_0091702 in sepsis-induced AKI have yet to be confirmed. Lipopolysaccharide (LPS) was used to induce HK2 cells to construct AKI cell models in vitro. Quantitative real-time PCR was used to measure the expression of circ_0091702, inflammatory cytokines, microRNA (miR)-545-3p and thrombospondin 2 (THBS2). Cell counting kit 8 assay and flow cytometry were used to assess cell viability and apoptosis. Besides, the protein levels of apoptosis markers and THBS2 were evaluated by western blot analysis. In addition, the concentrations of inflammatory cytokines were detected by enzyme-linked immunosorbent assay (ELISA). Cell oxidative stress was determined by detecting the contents of oxidative stress markers. Dual-luciferase reporter assay and RIP assay were used to confirm the relationship between miR-545-3p and circ_0091702 or miR-545-3p and THBS2. Circ_0091702 was downregulated in septic AKI patients and LPS-induced HK2 cells. Circ_0091702 could attenuate LPS-induced HK2 cell injury, while its silencing had an opposite effect. In the terms of mechanism, circ_0091702 could act as a sponge of miR-545-3p, and miR-545-3p could directly target THBS2. Functional experiments revealed that miR-545-3p could reverse the alleviating effect of circ_0091702 on LPS-induced HK2 cell injury, and THBS2 knockdown also could overturn the suppressing effect of miR-545-3p inhibitor on LPS-induced HK2 cell injury. Additionally, we also suggested that circ_0091702 could sponge miR-545-3p to regulate THBS2 expression. In conclusion, our results showed that circ_0091702 could suppress LPS-induced HK2 cell injury via the miR-545-3p/THBS2 axis, indicating that circ_0091702 might be an important biomarker for relieving sepsis-related AKI.

Tan M ，Bei R 《-》

Circ_0114428 Regulates Sepsis-Induced Kidney Injury by Targeting the miR-495-3p/CRBN Axis.

Septic acute kidney injury (AKI) is considered as a severe and common complication of sepsis, with complex pathogenesis. Recently, Circular RNA (circRNA) is considered to be implicated in this disease. This study was intended to elucidate the role of circ_0114428 and the potential mechanism of action in sepsis-induced kidney injury. Sepsis-induced kidney injury cell model was established in human kidney 2 (HK2) cells by the treatment of lipopolysaccharide (LPS). The expression of circ_0114428, CRBN mRNA, and miR-495-3p was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Cell viability was assessed by cell counting kit-8 (CCK-8) assay. The inflammatory response was monitored according to the release of proinflammatory factors by enzyme-linked immunosorbent assay (ELISA). Cell apoptosis was evaluated by flow cytometry assay. The activities of oxidative indicators were examined using the corresponding kits. Endoplasmic reticulum (ER) stress-related proteins and CRBN protein were quantified by western blot. RNA immunoprecipitation (RIP) assay was performed to ensure whether circ_0114428 could interact with Argonaute 2 (Ago2) protein. The potential miRNAs targeted by circ_0114428 were predicted by the bioinformatics tool and screened by RNA pull-down assay. The interaction between miR-495-3p and circ_0114428 or CRBN was validated by dual-luciferase reporter assay. The results showed that circ_0114428 and CRBN were upregulated in septic AKI serum specimens and LPS-induced HK2 cells. Circ_0114428 knockdown attenuated LPS-induced apoptosis, inflammation, oxidative stress, and ER stress, which were rescued by CRBN overexpression. Further analysis revealed that miR-495-3p was targeted by circ_0114428 and directly bound to CRBN, and circ_0114428 regulated CRBN expression by sponging miR-495-3p. Besides, miR-495-3p inhibition also reversed the effects of circ_0114428 knockdown. In conclusion, circ_00114428 knockdown attenuated LPS-induced HK2 cell injury by regulating CRBN expression via targeting miR-495-3p.

He Y ，Sun Y ，Peng J 《-》

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

Yang J ，Wu L ，Liu S ，Hu X ，Wang Q ，Fang L ... -  《-》

Resveratrol Inhibits circ_0074371-related Pathway to Alleviate Sepsis-induced Acute Kidney Injury.

Resveratrol has a protective effect on sepsis-induced acute kidney injury (AKI). Circ_0074371 has been confirmed to inhibit sepsis-induced AKI process, but whether resveratrol inhibits sepsis-induced AKI by regulating circ_0074371-related pathway remains unclear. In this study, lipopolysaccharide (LPS)-induced renal tubular epithelial cells (HK2) were used to mimic AKI cell models. Quantitative real-time PCR was used to detect relative expression of circ_0074371, microRNA (miR)-145-5p and inositol polyphosphate multikinase (IPMK). Cell proliferation and apoptosis were detected by cell counting kit 8 assay, EdU assay and flow cytometry. The levels of inflammation factors were measured by ELISA assay, and MDA level and SOD activity were examined to assess oxidative stress. Protein expression of IPMK was evaluated by western bolt analysis. The relationship between miR-145-5p and circ_0074371 or IPMK was confirmed by dual-luciferase reporter assay. It was showed that circ_0074371 was upregulated in AKI patients and LPS-induced HK2 cells, and silencing of circ_0074371 promoted proliferation and inhibited apoptosis, inflammation and oxidative stress in LPS-induced HK2 cells. In terms of mechanism, circ_0074371 sponged miR-145-5p to positively regulate IPMK. IPMK overexpression could reverse the relieving effect of circ_0074371 knockdown on LPS-induced HK2 cell injury. Moreover, resveratrol suppressed LPS-induced apoptosis, inflammation and oxidative stress in HK2 cells, and circ_0074371 overexpression also reversed the protective effect of resveratrol against LPS-induced cell injury. Our data suggested that resveratrol alleviated LPS-induced HK2 cell injury by inactivating the circ_0074371/miR-145-5p/IPMK axis.

Zhu D ，Wu X 《-》

Downregulation of circ-ZNF644 alleviates LPS-induced HK2 cell injury via miR-335-5p/HIPK1 axis.

Circular RNA (circRNA) has been confirmed to be involved in regulating sepsis-induced acute kidney injury (AKI). Our research aims to explore circ-ZNF644 role in the development of sepsis-induced AKI. Lipopolysaccharide (LPS) was used to induce kidney tubular epithelial cell (HK2) injury. ELISA assay was performed to measure the concentrations of inflammation factors. Cell functions were determined by cell counting kit 8 assay, EdU assay and flow cytometry. Protein expression was evaluated by Western blot analysis. Quantitative real-time PCR was used to detect relative expression of circ-ZNF644, miR-335-5p and homeodomain-interacting protein kinase 1 (HIPK1). RNA interaction was confirmed by dual-luciferase reporter assay and RIP assay. LPS enhanced HK2 cell inflammation, oxidative stress, apoptosis, and reduced proliferation. Circ-ZNF644 was overexpressed in sepsis-induced AKI patients. Circ-ZNF644 knockdown suppressed LPS-induced HK2 cell injury, and this effect could be revoked by miR-335-5p inhibitor. MiR-335-5p was sponged by circ-ZNF644, and its expression was downregulated in sepsis-induced AKI patients. HIPK1 was targeted by miR-335-5p, and its expression could be suppressed by circ-ZNF644 knockdown. MiR-335-5p had an inhibition effect on HK2 cell injury induced by LPS, and HIPK1 overexpression could reverse this effect. Circ-ZNF644 knockdown relieved LPS-induced HK2 cell injury through the miR-335-5p/HIPK1 axis, confirming that circ-ZNF644 contributed to sepsis-induced AKI.

Gong J ，Zhao S ，Luo S ，Yin S ，Li X ，Feng Y ... -  《-》