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 ... -  《-》

The novel biomarker circ_0020339 drives septic acute kidney injury by targeting miR-17-5p/IPMK axis.

Sepsis is a systemic life-threatening inflammatory disease, which leads to septic acute kidney injury (AKI). Circular RNAs (circRNAs) are involved in septic AKI. Herein, we aimed to expound the action of circ_0020339 in septic AKI. The dysregulation of plasma circRNAs between patients with septic non-AKI and patients with septic AKI were screened by circRNA chip. The dysregulation of circ_0020339, microRNA (miR)-17-5p, and inositol polyphosphate multi kinase (IPMK) mRNA was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Cell viability and apoptosis were measured by cell counting kit-8 (CCK-8) and flow cytometry, respectively. The release of serum creatinine (SCr), tissue inhibitor metalloproteinase-2 (TIMP-2), insulin-like growth factor binding protein-7 (IGFBP7), tumor necrosis factor (TNF)α and interleukin (IL)-1β was evaluated by enzyme-linked immunosorbent assay (ELISA). Bioinformatic analysis, dual-luciferase reporter assay and miRNA pull down assay were used to confirm the interaction between miR-17-5p and circ_0020339 or IPMK 3'untranslated region (UTR). Protein level of IPMK, TNF receptor-associated factor 6 (TRAF6), phosphorylated AKT (p-AKT)/total (t)-AKT, p-nuclear factor kappa-B (NF-κB) kinase (p-IKK)/t-IKK, p-inhibitor of NF-κB (p-IκB)α/t-IκBα, and p-p65/t-p65 were conducted by western blot. Circ_0020339 was upregulated in the plasma of patients with septic AKI as well as LPS-treated HK2 cells and C57BL/6 mice relative to the corresponding counterparts. Functionally, circ_0020339 was positively correlated with markers of renal functional injury and inflammation in patients with septic AKI; si-circ_0020339 facilitated cell proliferation, while restrained cell apoptosis and inflammation in LPS-triggered HK2 cells; meanwhile, si-circ_0020339 restrained survival rate, renal functional injury and inflammation in LPS-triggered C57BL/6 mice. Furthermore, circ_0020339 and IPMK 3'UTR shared the same complementary sites with miR-17-5p. si-circ_0020339 attenuated LPS-induced cell damage by targeting miR-17-5p/IPMK axis and inactivation of TRAF6/p-AKT/p-IKK/p-IκBα/p-p65. Altogether, plasma circ_0020339 serves as a novel diagnostic marker of patients with septic AKI.

Wang L ，Bayinchahan B ，Zhang D ，Wang Z ，Xiao D ... -  《-》

Circ-PRKCI Alleviates Lipopolysaccharide-induced Human Kidney 2 Cell Injury by Regulating miR-106b-5p/GAB1 Axis.

Xiong Y ，Wang Y ，Tian H ，Li Y ，Xu Q ，He Z ... -  《-》

Silencing circ_0074371 inhibits the progression of sepsis-induced acute kidney injury by regulating miR-330-5p/ELK1 axis.

Sepsis-induced acute kidney injury (AKI) is a common in clinic. Circular RNAs (circRNAs) play significant roles in ameliorating AKI. The purpose of this study was aimed to identify the role of circ_0074371 and the potential action mechanism in sepsis-induced AKI. AKI patients and healthy individual serum samples were collected and the relative expression of circ_0074371 was measured by real-time polymerase chain reaction (RT-PCR). HK2 cells were treated with different dose (0, 2.5, 5 and 10 μg/ml) lipopolysaccharide (LPS) to establish the AKI cell model. The cell viability and apoptosis of HK2 cells were detected using cell counting kit-8 (CCK-8) and flow cytometry, respectively. The contents of malondialdehyde (MDA), and superoxide dismutase (SOD) were evaluated using the relative commercial kits. The IL-1β and TNF-α levels in cell culture supernatants were measured by ELISA. The interaction relationship between miR-330-5p and circ_0074371 or ELK1 was predicted by Targetscan database and further confirmed by the dual-luciferase reporter assay system. The circ_0074371 expression was up-regulated in sepsis patients and LPS-induced HK2 cells. Silencing circ_0074371 promoted HK2 cells viability and inhibited the HK2 cells apoptosis. miR-330-5p inhibitor weakened circ_0074371 inhibitor-induced cell viability, apoptosis and oxidative stress. Further mechanism analysis showed that circ_0074371 acted as a sponge for miR-330-5p to increase ELK1 expression level. Importantly, miR-330-5p downregulation or ELK1 upregulation reversed the action of circ_0074371 knockdown on LPS-induced HK2 cells. Knockdown of circ_0074371 ameliorated LPS-induced HK2 cells apoptosis, inflammation and oxidative stress via regulating miR-330-5p/ELK1, opening a new window into the pathogenesis AKI.

Wang QY ，Zhang RR ，Cui L ，Sun YP ... -  《-》