Loganin exerts a protective effect on ischemia-reperfusion-induced acute kidney injury by regulating JAK2/STAT3 and Nrf2/HO-1 signaling pathways.

To investigate the role of loganin in hypoxia/reperfusion (H/R)-induced renal tubular epithelial cells and ischemia/reperfusion-induced acute kidney injury (AKI). Cells were received H/R treatment and cultured with different concentrations of loganin. The cell activity and apoptosis were detected. The expressions of apoptosis-related proteins, inflammatory factors, oxidative stress related molecules, and related molecules of JAK2/STAT3 and Nrf2/HO-1 signaling pathways were measured. AKI model of mice was established by I/R procedure, and the kidney was collected for hematoxylin and eosin (HE) staining. H/R treatment inhibited cell activity and apoptosis, but loganin attenuated the effect of H/R. Moreover, loganin inhibited H/R-induced inflammatory response and oxidative stress in tubular epithelial cells. Loganin down-regulated the expression of apoptosis-related proteins, suppressed JAK2/STAT3 pathway, and activated Nrf2/HO-1 pathway. In animal experiment, loganin reduced tubular injury in AKI mice.Loganin had anti-apoptotic, anti-inflammatory, and anti-oxidative stress effects on H/R-induced tubular epithelial cells, and could improve AKI in mice induced by I/R. This effect might be achieved by inhibiting JAK2/STAT3 and activating the Nrf2/HO-1 signaling pathway.

Huang F ，Wang X ，Xiao G ，Xiao J ... -  《-》

Loganin Attenuates Septic Acute Renal Injury with the Participation of AKT and Nrf2/HO-1 Signaling Pathways.

Sepsis, a destructive inflammatory response syndrome, is the principal reason to induce death in the intensive care unit. Loganin has been proved to possess the property of anti-inflammation, antioxidant, neuroprotection, and sedation. The primary aim of this study was to evaluate whether Loganin could alleviate acute kidney injury (AKI) during sepsis and investigate the latent mechanisms. Septic AKI models were established by cecal ligation and puncture (CLP) surgery in mice and given Loganin (20, 40, 80 mg/kg) by gavage. Lipopolysaccharides (LPS)-stimulated human kidney proximal tubular (HK2) cells incubated in Loganin (5, 10, 20 μ M) were used to explore the accurate mechanisms. Survival rate, renal function (creatinine and blood urea nitrogen), and renal pathological changes were detected in septic mice. Oxidative stress markers (SOD, GSH-Px, MDA, and SOD), mitochondrial membrane potential, mitochondrial calcium overload, and nuclear factor E2-related factor 2 (Nrf2)/heme-oxygenase 1 (HO-1) pathway activation in vivo and in vitro were determined by commercial kits and Western blot. Cell apoptosis, apoptotic-related protein (cleaved caspase-3, Bcl-2, and Bax) expression and protein kinase B (AKT) phosphorylation in vivo and in vitro were measured by TUNEL staining and Western blot. Finally, AKT blockage by 10 μM LY294002 or Nrf2 inhibition by10 μ M ML385 were utilized to prove the involvement of AKT and Nrf2/HO-1 pathway in AKI during sepsis. We found Loganin treatment (20, 40, 80 mg/kg) mitigated septic AKI reflected by elevated renal function and palliative pathological changes. Oxidative stress and apoptosis in the kidney and LPS-treated HK2 cells were also inhibited by Loganin administration, which was accompanied by AKT and Nrf2/HO-1 pathway activation. Besides, the protective effects of Loganin could be diminished by AKT or Nrf2 blockage, indicating the involvement of AKT and Nrf2/HO-1 pathway. The results suggested that the protective effects of Loganin on AKI during sepsis might be mediated by AKT and Nrf2/HO-1 pathway signaling activation in kidney proximal tubular cells.

Zhang J ，Wang C ，Kang K ，Liu H ，Liu X ，Jia X ，Yu K ... -  《Drug Design Development and Therapy》

β-Patchoulene Preconditioning Protects Mice Against Hepatic Ischemia-Reperfusion Injury by Regulating Nrf2/HO-1 Signaling Pathway.

Hepatic ischemia-reperfusion (I/R) injury is one of the main causes of liver dysfunction after the liver resection and transplantation. Hepatic I/R was characterized by the tissue hypoxia during ischemia phase and oxidative stress and immune response during hypoxia-reoxygenation. The objectives of the present study were to determine the protective effects of β-patchoulene (β-PAE), a novel bioactive agent, in a mice model of hepatic I/R injury and to explore its potential mechanisms. A segmental liver warm I/R injury model was performed by occluding the portal vessels for 1 h followed by 6-h reperfusion. Twenty-four mice were randomly divided into three groups: Sham, I/R, and I/R + β-PAE, with eight mice in each group. Mice were intravenously injected with β-PAE (10 mg/kg) or saline 2 h before surgery, and parameters were measured 6 h after designated treatment. Serum aminotransferase, histologic changes, cytokines expression, and apoptosis were determined. The potential effects of β-PAE on macrophage activation and apoptosis were further evaluated in a hypoxia and reperfusion (H/R) model in vitro. Oxidative stress markers (reactive oxygen species production and malondialdehyde) and cytokines expression were measured by commercial kits. Nrf2/HO-1 and NF-ƘB signaling pathways were determined by Western blotting. Finally, blockade of nuclear factor erythroid 2-related factor 2 (Nrf2) with ML385 was used to confirm the involvement of Nrf2/HO-1 pathway in H/R injury. Hepatic I/R induced apparent tissue injury as evidenced by the increased expression of serum aminotransferase, pro-inflammatory mediators production, hepatocellular apoptosis, and necrosis. β-PAE pretreatment protected mice against I/R-induced injury, which was proved by decreased serum aminotransferase and cytokines production, reduced TUNEL-positive cells, and alleviated histopathological lesion. Immunofluorescence staining showed that β-PAE suppressed the M1 polarization of Kupffer cell induced by I/R injury. Moreover, pretreatment with β-PAE suppressed H/R-induced cytokines expression and apoptosis in cultured macrophage. The mechanistic study demonstrated that β-PAE significantly promoted the nuclear Nrf2 translocation and upregulation of HO-1 while downregulating the NF-ƘB signaling pathway in both in vivo and in vitro experiments. Furthermore, blockade of Nrf2 abolished the protective effects of β-PAE on the inhibition of H/R-mediated oxidative stress, inflammatory response, and apoptosis in vitro. β-PAE preconditioning protects mice against hepatic I/R, which was at least in part through the reversing disequilibrium between Nrf2/HO-1 and NF-ƘB pathways. β-PAE might serve as a promising therapeutic agent in the treatment of hepatic I/R injury.

Tao T ，Ye B ，Xu Y ，Wang Y ，Zhu Y ，Tian Y ... -  《-》

Inhibition of PRMT5 Attenuates Oxidative Stress-Induced Pyroptosis via Activation of the Nrf2/HO-1 Signal Pathway in a Mouse Model of Renal Ischemia-Reperfusion Injury.

Extensive evidence has demonstrated that oxidative stress, pyroptosis, and proinflammatory programmed cell death are related to renal ischemia/reperfusion (I/R) injury. However, the underlying mechanism remains to be illustrated. Protein arginine methylation transferase 5 (PRMT5), which mediates arginine methylation involved in the regulation of epigenetics, exhibits a variety of biological functions and essential roles in diseases. The present study investigated the role of PRMT5 in oxidative stress and pyroptosis induced by I/R injury in a mouse model and in a hypoxia/reoxygenation (H/R) model of HK-2 cells. C57 mice were used as an animal model. All mice underwent right nephrectomy, and the left renal pedicles were either clamped or not. Renal I/R injury was induced by ligating the left renal pedicle for 30 min followed by reperfusion for 24 h. HK-2 cells were exposed to normal conditions or stimulation through H/R. EPZ015666(EPZ)-a selective potent chemical inhibitor-and small interfering RNA (siRNA) were administered to suppress the function and expression of PRMT5. The levels of urea nitrogen and creatinine in the serum and renal tissue injury were assessed. Immunohistochemistry, western blotting, and reverse transcription-polymerase chain reaction were used to evaluate pyroptosis-related proteins including nod-like receptor protein-3, ASC, caspase-1, caspase-11, GSDMD-N, and interleukin-1β. Cell apoptosis and cell viability were detected through flow cytometry, and the levels of reactive oxygen species (ROS) and hydrogen peroxide (H2O2) were measured. Ki-67 was used to assess the proliferation of renal tubular epithelium. In addition, the activity of malondialdehyde and superoxide dismutase was determined. I/R or H/R induced an increase in the expression of PRMT5. Inhibition of PRMT5 by EPZ alleviated oxidative stress and I/R- or H/R-induced pyroptosis. In renal tissue, the application of EPZ promoted the proliferation of tubular epithelium. In addition, H/R-induced pyroptosis in HK-2 cells was dependent on oxidative stress in vitro. Administration of either EPZ or siRNA led to decreased expression of pyroptosis-related proteins. Inhibition of PRMT5 also attenuated the I/R- or H/R-induced oxidative stress in vivo and in HK-2 cells, respectively. It also resulted in a distinct decrease in the levels of malondialdehyde and H2O2, and an apparent increase in superoxide dismutase activity in mouse renal tissue. Moreover, it led to a significant decrease in the levels of ROS and H2O2 in HK-2 cells. When activated, NF-E2-related factor/heme oxygenase-1 (Nrf2/HO-1)-a key regulator of various cytoprotective proteins that withstand oxidative damage-can decrease the generation of ROS. Nrf2/HO-1 was downregulated during I/R in tissues and H/R in HK-2 cells, and this effect was reversed by the PRMT5 inhibitor. Furthermore, the expressions of Nrf2 and HO-1 proteins were markedly upregulated by EPZ or siRNA against PRMT5. PRMT5 is involved in ischemia- and hypoxia-induced oxidative stress and pyroptosis in vitro and in vivo. Inhibition of PRMT5 may ameliorate renal I/R injury by suppressing oxidative stress and pyroptosis via the activation of the Nrf2/HO-1 pathway, as well as promoting the proliferation of tubular epithelium. Therefore, PRMT5 may be a promising therapeutic target.

Diao C ，Chen Z ，Qiu T ，Liu H ，Yang Y ，Liu X ，Wu J ，Wang L ... -  《-》

Salvianolate ameliorates renal tubular injury through the Keap1/Nrf2/ARE pathway in mouse kidney ischemia-reperfusion injury.

Acute kidney injury (AKI) is a common clinical disease characterized by rapid loss of renal function. Salvianolate is a prescribed Chinese medicine derived from traditional Chinese medicine Salvia miltiorrhiza bunge that possesses many pharmacological effects, the active components extracted from Salvia miltiorrhiza bunge have been proved to protect ischemia-reperfusion (I/R)-AKI. This study aims to validate the therapeutic effect of SAL on I/R-AKI, and explore its potential pharmacological mechanism. Mice were pretreated with/without salvianolate (10, 30, and 90 mg/kg) before renal ischemia-reperfusion operation. Serum creatinine, BUN, and H&E staining were performed to evaluate renal function. Immunofluorescence analysis was conducted to measure renal tubular injury including inflammatory factors and peroxide level. Apoptosis of the kidney tissues was determined by TUNEL assay. Keap1-Nrf2-ARE and apoptosis signaling pathways were measured by Western blot, RT-PCR, and YO-PRO-1 staining in kidneys or NRK52E cells. Pretreatment with SAL effectively alleviated renal function and ameliorated epithelial tubular injury, oxidative stress, and inflammatory response. Furthermore, the mechanistic study demonstrated that the SAL exerts anti-apoptotic effects through activation of the Keap1-Nrf2-ARE signaling pathway in renal tubular cells. These findings indicate the therapeutic benefit of salvianolate in the protection of renal injury from ischemia-reperfusion, and strengthen the evidence for the AKI treatment strategy by the anti-oxidative stress response, suggesting that SAL may be a potential agent for the treatment of AKI.

Sun D ，Cui S ，Ma H ，Zhu P ，Li N ，Zhang X ，Zhang L ，Xuan L ，Li J ... -  《-》