Adenovirus-mediated bcl-2 gene transfer inhibits renal ischemia/reperfusion induced tubular oxidative stress and apoptosis

Myocardial ischemia-reperfusion injury; Molecular mechanisms and prevention

Cardiovascular diseases are one of the leading causes of mortality in developed countries. Among cardiovascular disorders, myocardial infarction remains a life-threatening problem predisposing to the development and progression of ischemic heart failure. Ischemia/reperfusion (I/R) injury is a critical cause of myocardial injury. In recent decades, many efforts have been made to find the molecular and cellular mechanisms underlying the development of myocardial I/R injury and post-ischemic remodeling. Some of these mechanisms are mitochondrial dysfunction, metabolic alterations, inflammation, high production of ROS, and autophagy deregulation. Despite continuous efforts, myocardial I/R injury remains a major challenge in medical treatments of thrombolytic therapy, heart disease, primary percutaneous coronary intervention, and coronary arterial bypass grafting. The development of effective therapeutic strategies to reduce or prevent myocardial I/R injury is of great clinical significance.

Selenoprotein Gene mRNA Expression Evaluation During Renal Ischemia-Reperfusion Injury in Rats and Ebselen Intervention Effects

Effects of selenoproteins on many renal diseases have been reported. However, their role in renal ischemia-reperfusion (I/R) injury is unclear. The present study was performed to investigate the impact of ebselen and renal I/R injury on the expression of selenoproteins. Sprague-Dawley rats were pretreated with or without ebselen (10 mg/kg) through a daily single oral administration from 3 days before renal I/R surgery. RT-qPCR (real-time quantitative PCR) was performed to determine the mRNA expression of 25 selenoprotein genes in the renal tissues. The expression levels of two selenoproteins, including GPX3 (glutathione peroxidase 3) and DIO1 (iodothyronine deiodinase 1), were evaluated by Western blot or/and IHF (immunohistofluorescence) assays. Furthermore, renal function, renal damage, oxidative stress, and apoptosis were assessed. The results showed that in renal I/R injury, the mRNA levels of 15 selenoprotein genes (GPX1, GPX3, GPX4, DIO1, DIO2, TXNRD2, TXNRD3, SEPHS2, MSRB1, SELENOF, SELENOK, SELENOO, SELENOP, SELENOS, and SELENOT) were decreased, whereas those of eight selenoprotein genes (GPX2, GPX6, DIO3, TXNRD1, SELENOH, SELENOM, SELENOV, and SELENOW) were increased. I/R also induced a reduction in the expression levels of GPX3 and DIO1 proteins. In addition, our results indicated that ebselen reversed the changes in those selenoprotein genes, excluding SELENOH, SELENOM, SELENOP, and SELENOT, in renal I/R injury and alleviated I/R-induced renal dysfunction, tissue damage, oxidative stress, and apoptosis. To our knowledge, this is the first study to investigate the changes of 25 mammalian selenoprotein genes in renal I/R injury kidneys. The present study also provided more evidence for the roles of ebselen against renal I/R injury.

Alkaloid from Alstonia yunnanensis diels root against gastrointestinal cancer: Acetoxytabernosine inhibits apoptosis in hepatocellular carcinoma cells

Liver cancer belongs to Gastrointestinal (GI) malignancies which is a common clinical disease, a thorny public health problem, and one of the major diseases that endanger human health. Molecules from natural products (NPs) or their derivatives play an increasingly important role in various chronic diseases such as GI cancers. The chemical composition of the Alstonia yunnanensis Diels roots was studied using silica column chromatography, gel chromatography, recrystallization, and HPLC, and the compounds were structurally identified by modern spectral analysis using mass spectrometry (MS) and nuclear magnetic resonance (1H-, 13C-, HMQC-, HMBC-, and 1H-1HCOSY-NMR), ultraviolet and visible spectrum (UV), and electronic Circular Dichroism (ECD). Acetoxytabernosine (AC), an indole alkaloid with antitumor activity, was isolated from Alstonia yunnanensis Diels root. The current study aimed to investigate the influence of AC on the cell proliferation of BEL-7402 and SMMC7721 and to elucidate the underlying mechanism. The absolute configuration of AC was calculated by ECD (electronic circular dichroism). The effects of AC on the viability of different tumor cell lines were studied by the SRB method. The death mode of human hepatoma cells caused by AC was studied by TUNEL cell apoptosis detection and AnnexinV-FITC/PI double staining image. Mitochondrial membrane potential was detected by JC-1. The effects of AC on the expression of apoptosis-related proteins (Caspase9, Caspase3, and Parp-1) in SMMC7721 and BEL-7402 cells were detected by western blot. It was found that the absolute configuration of AC is 19(s), 20(s)-Acetoxytabernosine. AC could induce apoptosis of SMMC7721 and BEL-7402, and block the replication of DNA in the G1 phase. Under the treatment of AC, the total protein expression of apoptosis-related proteins (Caspase9, Caspase3, and Parp-1) significantly decreased in SMMC7721 and BEL-7402. The results suggested that AC induced apoptosis through a caspase-dependent intrinsic pathway in SMMC7721 and BEL-7402, and natural product-based drug development is an important direction in antitumor drug discovery and research.

Evaluation of Bcl-2 as a marker for chronic kidney disease prediction in cats

Chronic kidney disease (CKD) is a frequent condition in elderly cats. Bcl-2 is linked to kidney disease through the processes of apoptosis and fibrosis. The purpose of this study is to examine Bcl-2 levels in CKD and clinically healthy age-matched cats in order to evaluate the relationship between Bcl-2 levels, signalment, and blood parameters in cats with CKD. The circulating levels of Bcl-2 were determined using an immunoassay in twenty-four CKD cats and eleven clinically healthy age-matched cats by the utilization of the general linear model (GLM), Pearson correlation, principal component analysis (PCA), ROC curves, the Cox hazard model, and Kaplan-Meier survival analysis. These were all conducted in order to explore Bcl-2 levels and their connection with other variables. The Bcl-2 immunohistochemical intensity was graded in each glomerulus and tubulointerstitium. McNemar's test was performed in order to compare the expression of Bcl-2 in the two renal tissue sites. The circulating Bcl-2 of CKD cats was significantly lower than those of clinically healthy age-matched cats (P = 0.034). The presence of circulating Bcl-2 (P < 0.01) and the severity of CKD (P = 0.02) were both linked with the survival time of cats with CKD. The area under the curve (AUC) of Bcl-2 for detection of CKD was 0.723. In cats, decreased circulating Bcl-2 was associated with increased blood BUN, creatinine levels, and CKD severity. Bcl-2 protein expression was reduced in the renal tissues of CKD cats as the disease progressed, resulting in a decrease in their survival time. This study demonstrated that Bcl-2 may be effective in diagnosing feline CKD.

Intrarenal Arterial Transplantation of Dexmedetomidine Preconditioning Adipose Stem-Cell-Derived Microvesicles Confers Further Therapeutic Potential to Attenuate Renal Ischemia/Reperfusion Injury through miR-122-5p/Erythropoietin/Apoptosis Axis

Intravenous adipose mesenchymal stem cells (ADSCs) attenuate renal ischemia/reperfusion (IR) injury but with major drawbacks, including the lack of a specific homing effect after systemic infusion, cell trapping in the lung, and early cell death in the damaged microenvironment. We examined whether intrarenal arterial transplantation of dexmedetomidine (DEX) preconditioning ADSC-derived microvesicles (DEX-MVs) could promote further therapeutic potential to reduce renal IR injury. We evaluated the effect of DEX-MVs on NRK-52E cells migration, hypoxia/reoxygenation (H/R)-induced cell death, and reactive oxygen species (ROS) amount and renal IR model in rats. IR was established by bilateral 45 min ischemia followed by 4 h reperfusion. Intrarenal MVs or DEX-MVs were administered prior to ischemia. Renal oxidative stress, hemodynamics and function, western blot, immunohistochemistry, and tubular injury scores were determined. The miR-122-5p expression in kidneys was analyzed using microarrays and quantitative RT-PCR and its action target was predicted by TargetScan. DEX-MVs were more efficient than MVs to increase migration capability and to further decrease H/R-induced cell death and ROS level in NRK-52E cells. Consistently, DEX-MVs were better than MV in increasing CD44 expression, improving IR-depressed renal hemodynamics and renal erythropoietin expression, inhibiting IR-enhanced renal ROS level, tubular injury score, miR-122-5p expression, pNF-κB expression, Bax/caspase 3/poly(ADP-ribose) polymerase (PARP)-mediated apoptosis, blood urea nitrogen, and creatinine levels. The use of NRK-52E cells confirmed that miR-122-5p mimic via inhibiting erythropoietin expression exacerbated Bax-mediated apoptosis, whereas miR-122-5p inhibitor via upregulating erythropoietin and Bcl-2 expression reduced apoptosis. In summary, intrarenal arterial DEX-MV conferred further therapeutic potential to reduce renal IR injury through the miR-122-5p/erythropoietin/apoptosis axis.

Group II Metabotropic Glutamate Receptors Reduce Apoptosis and Regulate BDNF and GDNF Levels in Hypoxic-Ischemic Injury in Neonatal Rats

Birth asphyxia causes brain injury in neonates, but a fully successful treatment has yet to be developed. This study aimed to investigate the effect of group II mGlu receptors activation after experimental birth asphyxia (hypoxia-ischemia) on the expression of factors involved in apoptosis and neuroprotective neurotrophins. Hypoxia-ischemia (HI) on 7-day-old rats was used as an experimental model. The effects of intraperitoneal application of mGluR2 agonist LY379268 (5 mg/kg) and the specific mGluR3 agonist NAAG (5 mg/kg) (1 h or 6 h after HI) on apoptotic processes and initiation of the neuroprotective mechanism were investigated. LY379268 and NAAG applied shortly after HI prevented brain damage and significantly decreased pro-apoptotic Bax and HtrA2/Omi expression, increasing expression of anti-apoptotic Bcl-2. NAAG or LY379268 applied at both times also decreased HIF-1α formation. HI caused a significant decrease in BDNF concentration, which was restored after LY379268 or NAAG administration. HI-induced increase in GDNF concentration was decreased after administration of LY379268 or NAAG. Our results show that activation of mGluR2/3 receptors shortly after HI prevents brain damage by the inhibition of excessive glutamate release and apoptotic damage decrease. mGluR2 and mGluR3 agonists produced comparable results, indicating that both receptors may be a potential target for early treatment in neonatal HI.

Prazosin Treatment Protects Brain and Heart by Diminishing Oxidative Stress and Apoptotic Pathways After Renal Ischemia Reperfusion

Acute kidney injury (AKI) is a major medical challenge caused from renal ischemia-reperfusion (IR) injury connected with different cellular events in other distant organs. Renal IR-related oxidative stress and inflammation followed by cell apoptosis play a crucial role in IR-induced distant organ pathological damages. Prazosin has shown protective effects against IR-injuries. Thus, the current study intended to investigate the possible protective role of prazosin against the consequents of renal IR in the heart and brain tissues. To reach this goal, rats were randomly divided into 3 groups (n=7): Sham, IR and prazosin pretreatment-IR animals (1 mg/kg intraperitoneally injection of prazosin 45 min before IR induction). After 6 h reperfusion, lipid peroxidation and antioxidant markers levels were evaluated in the both, brain and heart tissue. Moreover, apoptotic pathway in the heart and brain tissues were assessed by western blotting. Accordingly, prazosin pretreatment in IR model rats could significantly increase the antioxidant capacity and attenuate apoptotic pathways by increasing the bcl-2 levels and decreasing the expression of Bax and caspase 3 enzymes (P<0.05). Thus, prazosin suppressed cellular damages of heart and brain tissues post kidney IR by anti-oxidative and anti-apoptotic effects, which suggests the plausible use of prazosin in improving the clinical outcomes during AKI after further investigations.

The Long Non-coding RNA SNHG12 Functions as a Competing Endogenous RNA to Modulate the Progression of Cerebral Ischemia/Reperfusion Injury

Increasing research has proved that long non-coding RNAs (lncRNAs) play a critical role in a variety of biological processes. However, their functions in cerebral ischemia are still unclear. We found that the small nucleolar RNA host gene 12 (SNHG12) is a new type of lncRNA induced by ischemia/reperfusion. Here, we show that the expression of SNHG12 was upregulated in the brain tissue of mice exposed to middle cerebral artery occlusion/reperfusion (MCAO/R) and primary mouse cerebral cortex neurons treated with oxygen-glucose deprivation/reoxygenation (OGD/R). Mechanistically, SNHG12 knockdown resulted in larger infarct sizes and worse neurological scores in MCAO/R mice. Consistent with the in vivo results, SNHG12 upregulation significantly increased the viability and prevented apoptosis of neurons cultured under OGD/R conditions. In addition, we found that SNHG12 acts as a competing endogenous RNA (ceRNA) with microRNA (miR)-136-5p, thereby regulating the inhibition of its endogenous target Bcl-2. Moreover, SNHG12 was proven to target miR-136-5p, increasing Bcl-2 expression, which finally led to the activation of PI3K/AKT signaling. In conclusion, we demonstrated that SNHG12 acts as a ceRNA of miR-136-5p, thereby targets and regulates the expression of Bcl-2, which attenuates cerebral ischemia/reperfusion injury via activation of the PI3K/AKT pathway. This knowledge helps to better understand the pathophysiology of cerebral ischemic stroke and may provide new treatment options for this disease.

Tetramethylpyrazine: An Active Ingredient of Chinese Herbal Medicine With Therapeutic Potential in Acute Kidney Injury and Renal Fibrosis

As an increasing public health concern worldwide, acute kidney injury (AKI) is characterized by rapid deterioration of kidney function. Although continuous renal replacement therapy (CRRT) could be used to treat severe AKI, effective drug treatment methods for AKI are largely lacking. Tetramethylpyrazine (TMP) is an active ingredient of Chinese herb Ligusticum wallichii (Chuan Xiong) with antioxidant and anti-inflammatory functions. In recent years, more and more clinical and experimental studies suggest that TMP might effectively prevent AKI. The present article reviews the potential mechanisms of TMP against AKI. Through search and review, a total of 23 studies were finally included. Our results indicate that the undergoing mechanisms of TMP preventing AKI are mainly related to reducing oxidative stress injury, inhibiting inflammation, preventing apoptosis of intrinsic renal cells, and regulating autophagy. Meanwhile, given that AKI and chronic kidney disease (CKD) are very tightly linked by each other, and AKI is also an important inducement of CKD, we thus summarized the potential of TMP impeding the progression of CKD through anti-renal fibrosis.

Calcium dobesilate alleviates renal dysfunction and inflammation by targeting nuclear factor kappa B (NF-κB) signaling in sepsis-associated acute kidney injury

Acute kidney injury (AKI) is a serious complication of sepsis that increases mortality and the risk of progression to chronic kidney disease. Oxidative stress and apoptosis are reported to exert critical function in the pathogenesis of sepsis-associated AKI. Calcium dobesilate (CaD) was reported to play a protective role in renal diseases. Therefore, we explored the antioxidant effect and potential mechanism of CaD in lipopolysaccharide (LPS)-induced AKI in mice. We evaluated renal function (blood urea nitrogen (BUN) and serum creatinine (SCr)), histopathology, oxidative stress (superoxide dismutase (SOD) and malondialdehyde (MDA)), inflammation cytokines, and apoptosis in kidneys of mice. The effect of CaD on NF-κB signaling was evaluated by Western blot. Our findings showed that CaD alleviated renal dysfunction and kidney injury, and also reversed upregulated MDA concentration and reduced SOD enzyme activity in AKI mice. Moreover, LPS-induced inflammatory response was attenuated by CaD. CaD treatment also reduced the apoptosis evoked by LPS. Additionally, CaD downregulated phosphorylation of nuclear factor kappa B (NF-κB) signaling components in LPS mice. Conclusively, CaD alleviates renal dysfunction and inflammation by targeting NF-κB signaling in sepsis-associated AKI.

Study of the Role of the Tyrosine Kinase Receptor MerTK in the Development of Kidney Ischemia-Reperfusion Injury in RCS Rats

Renal ischaemia reperfusion (I/R) triggers a cascade of events including oxidative stress, apoptotic body and microparticle (MP) formation as well as an acute inflammatory process that may contribute to organ failure. Macrophages are recruited to phagocytose cell debris and MPs. The tyrosine kinase receptor MerTK is a major player in the phagocytosis process. Experimental models of renal I/R events are of major importance for identifying I/R key players and for elaborating novel therapeutical approaches. A major aim of our study was to investigate possible involvement of MerTK in renal I/R. We performed our study on both natural mutant rats for MerTK (referred to as RCS) and on wild type rats referred to as WT. I/R was established by of bilateral clamping of the renal pedicles for 30' followed by three days of reperfusion. Plasma samples were analysed for creatinine, aspartate aminotransferase (ASAT), lactate dehydrogenase (LDH), kidney injury molecule -1 (KIM-1), and neutrophil gelatinase-associated lipocalin (NGAL) levels and for MPs. Kidney tissue damage and CD68-positive cell requirement were analysed by histochemistry. monocyte chemoattractant protein-1 (MCP-1), myeloperoxidase (MPO), inducible nitric oxide synthase (iNOS), and histone 3A (H3A) levels in kidney tissue lysates were analysed by western blotting. The phagocytic activity of blood-isolated monocytes collected from RCS or WT towards annexin-V positive bodies derived from cultured renal cell was assessed by fluorescence-activated single cell sorting (FACS) and confocal microscopy analyses. The renal I/R model for RCS rat described for the first time here paves the way for further investigations of MerTK-dependent events in renal tissue injury and repair mechanisms.

Lipidomics Provides New Insight into Pathogenesis and Therapeutic Targets of the Ischemia-Reperfusion Injury

Lipids play an essential role in both tissue protection and damage. Tissue ischemia creates anaerobic conditions in which enzyme inactivation occurs, and reperfusion can initiate oxidative stress that leads to harmful changes in membrane lipids, the formation of aldehydes, and chain damage until cell death. The critical event in such a series of harmful events in the cell is the unwanted accumulation of fatty acids that leads to lipotoxicity. Lipid analysis provides additional insight into the pathogenesis of ischemia/reperfusion (I/R) disorders and reveals new targets for drug action. The profile of changes in the composition of fatty acids in the cell, as well as the time course of these changes, indicate both the mechanism of damage and new therapeutic possibilities. A therapeutic approach to reperfusion lipotoxicity involves attenuation of fatty acids overload, i.e., their transport to adipose tissue and/or inhibition of the adverse effects of fatty acids on cell damage and death. The latter option involves using PPAR agonists and drugs that modulate the transport of fatty acids via carnitine into the interior of the mitochondria or the redirection of long-chain fatty acids to peroxisomes.

The effects of meldonium on the acute ischemia/reperfusion liver injury in rats

Acute ischemia/reperfusion (I/R) liver injury is a clinical condition challenging to treat. Meldonium is an anti-ischemic agent that shifts energy production from fatty acid oxidation to less oxygen-consuming glycolysis. Thus, we investigated the effects of a 4-week meldonium pre-treatment (300 mg/kg b.m./day) on the acute I/R liver injury in Wistar strain male rats. Our results showed that meldonium ameliorates I/R-induced liver inflammation and injury, as confirmed by liver histology, and by attenuation of serum alanine- and aspartate aminotransferase activity, serum and liver high mobility group box 1 protein expression, and liver expression of Bax/Bcl2, haptoglobin, and the phosphorylated nuclear factor kappa-light-chain-enhancer of activated B cells. Through the increased hepatic activation of the nuclear factor erythroid 2-related factor 2, meldonium improves the antioxidative defence in the liver of animals subjected to I/R, as proved by an increase in serum and liver ascorbic/dehydroascorbic acid ratio, hepatic haem oxygenase 1 expression, glutathione and free thiol groups content, and hepatic copper-zinc superoxide dismutase, manganese superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase activity. Based on our results, it can be concluded that meldonium represent a protective agent against I/R-induced liver injury, with a clinical significance in surgical procedures.

Berberine protects human and rat cardiomyocytes from hypoxia/reoxygenation-triggered apoptosis

Berberine (BBR) confers potential cardioprotective effects. However, the relevant mechanisms underlying its regulation of cardiomyocyte survival following hypoxia/reoxygenation (H/R) treatment remain unknown. The present study investigated whether BBR could protect H/R by suppressing apoptosis and explored how TGF-β/Smad4 signaling pathway influenced H/R in vitro. Two cardiomyocyte cell lines-AC16 and H9c2- were treated with H/R and BBR. The survival and apoptosis of these two cell lines were assessed using the MTT and BrdU assays and western blotting (WB) and flow cytometry. Mitochondrial reactive oxygen species (ROS) and caspase (Cas)-3, Cas-8, and Cas-9 activation were evaluated using enzyme-linked immunosorbent assay as well as WB. Compared to the control group, H/R resulted in notable cell apoptosis, whereas BBR treatment evidently counteracted the process. BBR also markedly suppressed H/R-triggered excessive mitochondrial ROS generation and inhibited Smad4 expression. Overexpressing Smad4 in BBR-treated H/R-exposed cardiomyocytes reversed the effect of BBR treatment on apoptosis. Therefore, BBR protects H/R-treated cardiomyocytes from apoptosis by inhibiting the TGF-β/Smad4 signaling pathway.

Dexmedetomidine Alleviates Lipopolysaccharide-Induced Acute Kidney Injury by Inhibiting p75NTR-Mediated Oxidative Stress and Apoptosis

Oxidative stress and apoptosis play a key role in the pathogenesis of sepsis-associated acute kidney injury (AKI). Dexmedetomidine (DEX) may present renal protective effects in sepsis. Therefore, we studied antioxidant effects and the mechanism of DEX in an inflammatory proximal tubular epithelial cell model and lipopolysaccharide- (LPS-) induced AKI in mice. Methods. We assessed renal function (creatinine, urea nitrogen), histopathology, oxidative stress (malondialdehyde (MDA) and superoxide dismutase (SOD)), and apoptosis (TUNEL staining and Cleaved caspase-3) in mice. In vitro experiments including Cleaved caspase-3 and p75NTR/p38MAPK/JNK signaling pathways were evaluated using western blot. Reactive oxidative species (ROS) production and apoptosis were determined using flow cytometry. Results. DEX significantly improved renal function and kidney injury and also revert the substantially increased level of MDA concentrations as well as the reduction of the SOD enzyme activity found in LPS-induced AKI mice. In parallel, DEX treatment also reduced the apoptosis and Cleaved caspase-3 expression evoked by LPS. The expression of p75NTR was increased in kidney tissues of mice with AKI but decreased after treatment with DEX. In cultured human renal tubular epithelial cell line (HK-2 cells), DEX inhibited LPS-induced apoptosis and generation of ROS, but this was reversed by overexpression of p75NTR. Furthermore, pretreatment with DEX significantly downregulated phosphorylation of JNK and p38MAPK in LPS-stimulated HK-2 cells, and this effect was abolished by overexpression of p75NTR. Conclusion. DEX ameliorated AKI in mice with sepsis by partially reducing oxidative stress and apoptosis through regulation of p75NTR/p38MAPK/JNK signaling pathways.

Multiple Progressive Thermopreconditioning Improves Cardiac Ischemia/Reperfusion-induced Left Ventricular Contractile Dysfunction and Structural Abnormality in Rat

BACKGROUND

Triple progressive thermopreconditioning (3PTP) may induce high Hsp-70 expression to maintain cardiac function. We suggest that 3PTP may reduce myocardial ischemia/reperfusion (I/R) injury during organ transplantation through Bag3/Hsp-70 mediated defense mechanisms.

METHODS

Male Wistar rats were divided into sham control group and 72 h after 3PTP in a 42°C water bath (3PTP) group. Rats underwent 60 min of ischemia by occlusion of the left anterior descending coronary artery followed by 240 min reperfusion. Hemodynamic parameters, including the electrocardiogram, microcirculation, heart rate, left ventricular end-diastolic pressure, maximal rate of rise (+dp/dt), and fall (-dp/dt) in the left ventricular pressure for index of contraction and relaxation were determined. Myocardial infarct size was evaluated by the Evans blue-2,3,5-triphenyltetrazolium chloride method. 3PTP-induced protective mechanisms were determined by Western blot and immunohistochemistry.

RESULTS

Cardiac I/R depressed cardiac microcirculation, induced S-T segment elevation, and R-R and P-R interval elongation increased infarct size associated with erythrocyte extravasation, leukocytes and macrophage/monocyte infiltration, granulocyte colony-stimulating factor, poly(ADP-ribose) polymerase 1 stain, and transferase-mediated dUTP-biotin nick end labeling positive cells. However, 3PTP evoked significant cardioprotection against I/R injury, characterized by the increased +dp/dt value and the decreased elevated left ventricular end-diastolic pressure, erythrocyte extravasation, leukocyte and macrophage/monocyte infiltration, granulocyte colony-stimulating factor expression, poly(ADP-ribose) polymerase 1 expression, transferase-mediated dUTP-biotin nick end labeling positive cells, and fragmentation and infarct area. In addition, 3PTP increased Hsp-70 and Bag3 expression and decreased Bax/Bcl-2 ratio, but did not affect the Beclin-1 and LC3-II/LC3-I ratio in the heart with I/R injury.

CONCLUSIONS

3PTP therapies may through Bag3 upregulation alleviate I/R injury-induced left ventricular structural deterioration and dysfunction.

NOX1 Inhibition Attenuates Kidney Ischemia-Reperfusion Injury via Inhibition of ROS-Mediated ERK Signaling

The protective effects of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) 1 inhibition against kidney ischemia-reperfusion injury (IRI) remain uncertain. The bilateral kidney pedicles of C57BL/6 mice were clamped for 30 min to induce IRI. Madin–Darby Canine Kidney (MDCK) cells were incubated with H₂O₂ (1.4 mM) for 1 h to induce oxidative stress. ML171, a selective NOX1 inhibitor, and siRNA against NOX1 were treated to inhibit NOX1. NOX expression, oxidative stress, apoptosis assay, and mitogen-activated protein kinase (MAPK) pathway were evaluated. The kidney function deteriorated and the production of reactive oxygen species (ROS), including intracellular H₂O₂ production, increased due to IRI, whereas IRI-mediated kidney dysfunction and ROS generation were significantly attenuated by ML171. H₂O₂ evoked the changes in oxidative stress enzymes such as SOD2 and GPX in MDCK cells, which was mitigated by ML171. Treatment with ML171 and transfection with siRNA against NOX1 decreased the upregulation of NOX1 and NOX4 induced by H₂O₂ in MDCK cells. ML171 decreased caspase-3 activity, the Bcl-2/Bax ratio, and TUNEL-positive tubule cells in IRI mice and H₂O₂-treated MDCK cells. Among the MAPK pathways, ML171 affected ERK signaling by ERK phosphorylation in kidney tissues and tubular cells. NOX1-selective inhibition attenuated kidney IRI via inhibition of ROS-mediated ERK signaling.

Dihydroartemisinin Induces Growth Arrest and Overcomes Dexamethasone Resistance in Multiple Myeloma

The discovery of artemisinin (ART) for malaria treatment won the 2015 Nobel Prize in Medicine, which inspired the rediscovery and development of ART for the treatment of other diseases including cancer. In this study, we investigated the potential therapeutic effect of ART and dihydroartemisinin (DHA) on multiple myeloma (MM) cells including primary MM cells and in 5TMM3VT mouse model. Both in vitro and in vivo experiments showed that DHA might be a more promising anti-MM agent with significantly improved efficacy compared to ART. Mechanistic analyses suggested that DHA activated the mitochondrial apoptotic pathway by interacting with ferrous (Fe2+) ions and oxygen to produce reactive oxygen species (ROS). Intriguingly, DHA could reverse the upregulated expression of B-cell lymphoma 2 (Bcl-2) protein, a typical mitochondrial apoptotic marker, induced by dexamethasone (Dexa) in MM. We further demonstrated that DHA treatment could overcome Dexa resistance and enhance Dexa efficacy in MM. Additionally, DHA combined with Dexa resulted in increased ROS production and cytochrome C translocation from the mitochondria to the cytoplasm, resulting in alterations to the mitochondrial membrane potential and caspase-mediated apoptosis. In summary, our study demonstrated that DHA was superior to ART in MM treatment and overcame Dexa resistance both in vitro and in vivo, providing a promising therapeutic strategy for MM therapy.

Edaravone Ameliorates Renal Warm Ischemia-Reperfusion Injury by Downregulating Endoplasmic Reticulum Stress in a Rat Resuscitation Model

Background

This study was conducted to explore whether the effect of edaravone (5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol3-one, EDR) can ameliorate renal warm ischemia-reperfusion injury (IRI) by modulating endoplasmic reticulum stress (ERS) and its downstream effector after cardiac arrest (CA) and cardiopulmonary resuscitation (CPR) in a rat model.

Methods

The rats (n=10) experienced anaesthesia and intubation followed by no CA inducement were defined as the Sham group. Transoesophageal alternating current stimulation was employed to establish 8 min of CA followed by conventional CPR for a resuscitation model. The rats with successful restoration of spontaneous circulation (ROSC) randomly received EDR (3 mg/kg, EDR group, n=10) or equal volume normal saline solution (the NS group, n=10). At 24 hr after ROSC, serum creatinine (SCR), blood urea nitrogen (BUN) levels, and cystatin-C (Cys-C) levels were determined and the protein level of glucose-regulated protein (GRP78), C/EBP homologous protein (CHOP), extracellular signal-regulated kinase (ERK), phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK1/2), Bax/Bcl-2, and caspase-3 were detected by Western blot method.

Results

At 24 hrs after ROSC, SCR, BUN and Cys-C were obviously increased and the proteins expression, including GRP78, CHOP and p-ERK1/2, cleaved-caspase 3 Bax/Bcl-2 ratio, were significantly upregulated in the NS group compared with the Sham group (p<0.05). The remarkable improvement of these adverse outcomes was observed in the EDR group (p<0.05).

Conclusion

In conclusion, we found that EDR ameliorates renal warm IRI by downregulating ERS and its downstream effectors in a rat AKI model evoked by CA/CPR. These data may provide evidence for future therapeutic benefits of EDR against AKI induced by CA/CPR.

Sulforaphane improves voiding function via the preserving mitochondrial function in diabetic rats

BACKGROUND

Hyperglycemia evoked oxidative stress contributing to diabetes (DM)-induced voiding dysfunction. We explored whether antioxidant sulforaphane,a NF-E2-related nuclear factor erythroid-2 (Nrf-2) activator, may ameliorate DM-induced bladder dysfunction.

METHODS

DM was induced by streptozotocin and sulforaphanewas administered before DM induction.Bladder reactive oxygen species (ROS) were determined by an ultrasensitive chemiluminescence analyzer. Mitochondrial function index mitochondrial Bax and cytosolic cytochrome c, antioxidant defense Nrf-2/HO-1, endoplasmic reticulum stress marker ATF-6/CHOP, and caspase 3/PARP were evaluated by Western blot.

RESULTS

DM increased Keap1 and reduced Nrf-2 expression, associated with increase of bladder ROS, mitochondrial Bax translocation, cytosolic cytochrome c release, ATF-6/CHOP, caspase-3/PARP in bladders which resulted in voiding dysfunction by increased intercontraction intervals and micturition duration. However, sulforaphanesignificantly increased nuclear Nrf-2/HO-1axis expression, decreased bladder ROS amount, mitochondrial Bax translocation, cytochrome c release, ATF-6/CHOP and caspase 3/PARP/apoptosis, thereby improved the voiding function by the shortened intercontraction intervals and micturition duration.

CONCLUSION

We suggest that sulforaphanevia activating Nrf-2/HO-1 signaling preserved mitochondrial function and suppressed DM-induced ROS, endoplasmic reticulum stress, apoptosis and voiding dysfunction.

The Effects of Meldonium on the Renal Acute Ischemia/Reperfusion Injury in Rats

Acute renal ischemia/reperfusion (I/R) injury is a clinical condition that is challenging to treat. Meldonium is an anti-ischemic agent that shifts energy production from fatty acid oxidation to less oxygen-consuming glycolysis. Thus, in this study we investigated the effects of a four-week meldonium pre-treatment (300 mg/kg b.m./day) on acute renal I/R in male rats (Wistar strain). Our results showed that meldonium decreased animal body mass gain, food and water intake, and carnitine, glucose, and lactic acid kidney content. In kidneys of animals subjected to I/R, meldonium increased phosphorylation of mitogen-activated protein kinase p38 and protein kinase B, and increased the expression of nuclear factor erythroid 2-related factor 2 and haeme oxygenase 1, causing manganese superoxide dismutase expression and activity to increase, as well as lipid peroxidation, cooper-zinc superoxide dismutase, glutathione peroxidase, and glutathione reductase activities to decrease. By decreasing the kidney Bax/Bcl2 expression ratio and kidney and serum high mobility group box 1 protein content, meldonium reduced apoptotic and necrotic events in I/R, as confirmed by kidney histology. Meldonium increased adrenal noradrenaline content and serum, adrenal, hepatic, and renal ascorbic/dehydroascorbic acid ratio, which caused complex changes in renal lipidomics. Taken together, our results have confirmed that meldonium pre-treatment protects against I/R-induced oxidative stress and apoptosis/necrosis.

Gene therapy research for kidney diseases

A resurgence in the development of newer gene therapy systems has led to recent successes in the treatment of B cell cancers, retinal degeneration and neuromuscular atrophy. Gene therapy offers the ability to treat the patient at the root cause of their malady by restoring normal gene function and arresting the pathological progression of their genetic disease. The current standard of care for most genetic diseases is based upon the symptomatic treatment with polypharmacy while minimizing any potential adverse effects attributed to the off-target and drug-drug interactions on the target or other organs. In the kidney, however, the development of gene therapy modifications to specific renal cells has lagged far behind those in other organ systems. Some positive strides in the past few years provide continued enthusiasm to invest the time and effort in the development of new gene therapy vectors for medical intervention to treat kidney diseases. This mini-review will systematically describe the pros and cons of the most commonly tested gene therapy vector systems derived from adenovirus, retrovirus, and adeno-associated virus and provide insight about their potential utility as a therapy for various types of genetic diseases in the kidney.

Exenatide Reduces Graft Injury in a Rat Transplantation Model Using Kidneys Donated after Cardiac Death

Besides being used in the therapy of type 2 diabetes, exenatide reduces cerebral ischemia-reperfusion (I/R) injury. We evaluated the potential effects of exenatide on inhibition of apoptosis in kidney grafts donated after cardiac death and on reduction of I/R injury after kidney transplantation (KTx) in a rat model. We used a rat syngeneic KTx model with kidney grafts obtained after cardiac death, and apoptosis was detected in the graft before KTx. Graft function, rat survival, morphologic examination, and activation of inflammatory molecules were analyzed after KTx. By the end of the cold storage, exenatide pretreatment donors had significantly reduced caspase pathway activation, terminal deoxynucleotidyl transferase dUTP nick-end labeling--positive cells, release of mitochondrial porin proteins into the cytosol, and expression of cleaved caspase-3 and poly (ADP-ribose) polymerase in kidney grafts. Exenatide pretreatment improved renal function survival rate with lower scores of acute tubular necrosis, infiltrating macrophages, and interstitial fibrosis as well as reduced messenger RNA expression of inflammatory mediators (tumor necrosis factor α, interleukin-6, interleukin-1β, and intercellular adhesion molecule-1) after KTx. Our study showed that exenatide reduced I/R injury in kidneys donated after cardiac death in a rat transplantation model and improved recipient survival and graft function.

Toxoplasma gondii ROP18 inhibits human glioblastoma cell apoptosis through a mitochondrial pathway by targeting host cell P2X1

Background

Apoptosis plays a critical role in the embryonic development, homeostasis of immune system and host defense against intracellular microbial pathogens. Infection by the obligate intracellular pathogen Toxoplasma gondii can both inhibit and induce host cell apoptosis; however, the parasitic factors involved remain unclear. The T. gondii virulence factor ROP18 (TgROP18) has been reported to regulate host cell apoptosis; nevertheless, results for this regulation have been rarely reported or have provided contradictory findings. Human purinergic receptor 1 (P2X1) is an ATP-gated ion channel that responds to ATP stimulation and functions in cell apoptosis mediation. The precise roles of TgROP18 in T. gondii pathogenesis, and the relationship between TgROP18 and host P2X1 in host cell apoptosis are yet to be revealed.

Methods

Apoptosis rates were determined by flow cytometry (FCM) and TUNEL assay. The interaction between TgROP18 and the host P2X1 was measured by fluorescence resonance energy transfer (FRET) and co-immunoprecipitation (co-IP) assay. Calcium influx and mitochondrial membrane depolarization were determined by FCM after JC-1 staining. The translocation of cytochrome C (Cyt C), Bax and Bcl2 proteins, expression of the apoptotic proteins PARP and caspase activation were detected by western blotting.

Results

The apoptosis rates of glial or immune cells (human SF268, mouse RAW264.7 and human THP-1 cells) infected by any T. gondii strain (RH-type I, ME49-type II and VEG-type III) were significantly inhibited compared with their uninfected controls. TgROP18 inhibited ATP-induced apoptosis of SF268 with P2X1 expression, but had no effect on RAW264.7 or THP-1 cells without detectable P2X1 expression. It was further identified that TgROP18 interacted with P2X1, and overexpression of ROP18 in COS7 cells significantly inhibited cell apoptosis mediated by P2X1. Moreover, TgROP18 also inhibited P2X1-mediated Ca²⁺ influx, translocation of cytochrome C from the mitochondria to the cytosol, and ATP-triggered caspase activation.

Conclusions

Toxoplasma gondii infection inhibits ATP-induced host cell apoptosis, regardless of strain virulence and host cell lines. TgROP18 targets the purinergic receptor P2X1 of the SF268 human neural cells and inhibits ATP-induced apoptosis through the mitochondrial pathway, suggesting a sensor role for the host proapoptotic protein P2X1 in this process.

Electronic supplementary material

The online version of this article (10.1186/s13071-019-3529-1) contains supplementary material, which is available to authorized users.

Fimasartan attenuates renal ischemia-reperfusion injury by modulating inflammation-related apoptosis

Fimasartan, a new angiotensin II receptor antagonist, reduces myocyte damage and stabilizes atherosclerotic plaque through its anti-inflammatory effect in animal studies. We investigated the protective effects of pretreatment with fimasartan on ischemia-reperfusion injury (IRI) in a mouse model of ischemic renal damage. C57BL/6 mice were pretreated with or without 5 (IR-F5) or 10 (IR-F10) mg/kg/day fimasartan for 3 days. Renal ischemia was induced by clamping bilateral renal vascular pedicles for 30 min. Histology, pro-inflammatory cytokines, and apoptosis assays were evaluated 24 h after IRI. Compared to the untreated group, blood urea nitrogen and serum creatinine levels were significantly lower in the IR-F10 group. IR-F10 kidneys showed less tubular necrosis and interstitial fibrosis than untreated kidneys. The expression of F4/80, a macrophage infiltration marker, and tumor necrosis factor (TNF)-α, decreased in the IR-F10 group. High-dose fimasartan treatment attenuated the upregulation of TNF-α, interleukin (IL)-1β, and IL-6 in ischemic kidneys. Fewer TUNEL positive cells were observed in IR-F10 compared to control mice. Fimasartan caused a significant decrease in caspase-3 activity and the level of Bax, and increased the Bcl-2 level. Fimasartan preserved renal function and tubular architecture from IRI in a mouse ischemic renal injury model. Fimasartan also attenuated upregulation of inflammatory cytokines and decreased apoptosis of renal tubular cells. Our results suggest that fimasartan inhibited the process of tubular injury by preventing apoptosis induced by the inflammatory pathway.

Tempol Protects Against Acute Renal Injury by Regulating PI3K/Akt/mTOR and GSK3β Signaling Cascades and Afferent Arteriolar Activity

BACKGROUND/AIMS

Free radical scavenger tempol is a protective antioxidant against ischemic injury. Tubular epithelial apoptosis is one of the main changes in the renal ischemia/reperfusion (I/R) injury. Meanwhile some proteins related with apoptosis and inflammation are also involved in renal I/R injury. We tested the hypothesis that tempol protects against renal I/R injury by activating protein kinase B/mammalian target of rapamycin (PKB, Akt/mTOR) and glycogen synthase kinase 3β (GSK3β) pathways as well as the coordinating apoptosis and inflammation related proteins.

METHODS

The right renal pedicle of C57Bl/6 mouse was clamped for 30 minutes and the left kidney was removed in the study. The renal injury was assessed with serum parameters by an automatic chemistry analyzer. Renal expressions of Akt/mTOR and GSK3β pathways were measured by western blot in I/R mice treated with saline or tempol (50mg/kg) and compared with sham-operated mice.

RESULTS

The levels of blood urea nitrogen (BUN), creatinine and superoxide anion (O2.-) increased, and superoxide dismutase (SOD) and catalase (CAT) decreased significantly after renal I/R injury. However, tempol treatment prevented the changes. Besides, I/R injury reduced renal expression of p-Akt, p-GSK3β, p-mTOR, Bcl2 and increased NF-κB, p-JNK and p53 in kidney, tempol significantly normalized these changes. In addition, renal I/R injury reduced the response of afferent arteriole to Angiotensin II (Ang II), while tempol treatment improved the activity of afferent arteriole.

CONCLUSION

Tempol attenuates renal I/R injury. The protective mechanisms seem to relate with activation of PI3K/Akt/mTOR and GSK3β pathways, inhibition of cellular damage markers and inflammation factors, as well as improvement of afferent arteriolar activity.

The Role of BCL-2 Family Members in Acute Kidney Injury

B-cell lymphoma 2 (BCL-2) family proteins gather at the biologic cross-roads of renal cell survival: the outer mitochondrial membrane. Despite shared sequence and structural features, members of this conserved protein family constantly antagonize each other in a life-and-death battle. BCL-2 members innocently reside within renal cells until activated or de-activated by physiologic stresses caused by common nephrotoxins, transient ischemia, or acute glomerulonephritis. Recent experimental data not only illuminate the intricate mechanisms of apoptosis, the most familiar form of BCL-2-mediated cell death, but emphasizes their newfound roles in necrosis, necroptosis, membrane pore transition regulated necrosis, and other forms of acute cell demise. A major paradigm shift in non-cell death roles of the BCL-2 family has occurred. BCL-2 proteins also regulate critical daily renal cell housekeeping functions including cell metabolism, autophagy (an effective means for recycling cell components), mitochondrial morphology (organelle fission and fusion), as well as mitochondrial biogenesis. This article considers new concepts in the biochemical and structural regulation of BCL-2 proteins that contribute to membrane pore permeabilization, a universal feature of cell death. Despite these advances, persistent BCL-2 family mysteries continue to challenge cell biologists. Given their interface with many intracellular functions, it is likely that BCL-2 proteins determine cell viability under many pathologic circumstances relevant to the nephrologist and, as a consequence, represent an ideal therapeutic target.

Berberine prevents the apoptosis of mouse podocytes induced by TRAF5 overexpression by suppressing NF-κB activation

Berberine (BBR) has previously been found to exert beneficial effects on renal injury in experimental rats. However, the mechanisms underlying these effects are not yet fully understood. Tumor necrosis factor (TNF) receptor-associated factor 5 (TRAF5) has been demonstrated to mediate the activation of nuclear factor-κB (NF-κB), which has been implicated in the pathogenesis of chronic kidney disease (CKD). The aim of this study was to investigate the effects of BBR on kidney injury and the activation of the NF-κB signaling pathway in mouse podocytes. TRAF5 was found to be overexpressed in patients with CKD and chronic renal failure (CRF) (data obtained from the dataset GSE48944, as well as from patients at Shuguang Hospital). TRAF5 overexpression significantly inhibited cell viability and induced the apoptosis of mouse podocytes. However, BBR prevented the decrease in cell viability and the apoptosis induced by TRAF5 overexpression. The NF-κB inhibitor, caffeic acid phenethyl ester (CAPE), mimicked the protective effects of BBR, as evidenced by the increased expression of nephrin and podocin, and the decreased the expression of caspase-3 and the ratio of Bax/Bcl-2. Moreover, BBR prevented the decrease in cell viability decrease and the apoptosis induced by TNF-α, interleukin (IL)-6 and lipopolysaccharide (LPS). Taken together, our data indicate that BBR exerts protective effects against CRF partly through the TRAF5-mediated activation of the NF-κB signaling pathway in mouse podocytes.

Glucagon-like peptide-1 receptor agonist activation ameliorates venous thrombosis-induced arteriovenous fistula failure in chronic kidneyd isease

High shear stress that develops in the arteriovenous fistula of chronic kidney diseases (CKD) may increase H2O2 and thromboxane A2 (TXA2) release, thereby exacerbating endothelial dysfunction, thrombosis, and neointimal hyperplasia. We investigated whether glucagon-like peptide-1 receptor agonist/exendin-4, a potentially cardiovascular protective agent, could improve TXA2-induced arteriovenous fistula injury in CKD. TXA2 administration to H2O2-exposed human umbilical vein endothelial cells increased apoptosis, senescence, and detachment; these phenotypes were associated with the downregulation of phosphorylated endothelial nitric oxide synthase/heme oxygenase-1 (eNOS/HO-1) signalling. Exendin-4 reduced H2O2/TXA2-induced endothelial injury via inhibition of apoptosis-related mechanisms and restoration of phosphorylated eNOS/HO-1 signalling. Male Wistar rats subjected to right common carotid artery-external jugular vein anastomosis were treated with exendin-4 via cervical implant osmotic pumps for 16–42 days. High shear stress induced by the arteriovenous fistula significantly increased venous haemodynamics, blood and tissue H2O2 and TXB2 levels, macrophage/monocyte infiltration, fibrosis, proliferation, and adhesion molecule-1 expression. Apoptosis was also increased due to NADPH oxidase gp91 activation and mitochondrial Bax translocation in the proximal end of the jugular vein of CKD rats. Exendin-4-treatment of rats with CKD led to the restoration of normal endothelial morphology and correction of arteriovenous fistula function. Exendin-4 treatment or thromboxane synthase gene deletion in CKD mice markedly reduced ADP-stimulated platelet adhesion to venous endothelium, and prevented venous occlusion in FeCl3-injured vessels by upregulation of HO-1. Together, these data reveal that the use of glucagon-like peptide-1 receptor agonists is an effective strategy for treatment of CKD-induced arteriovenous fistula failure.

Conjugated linoleic acid rat pretreatment reduces renal damage in ischemia/reperfusion injury: Unraveling antiapoptotic mechanisms and regulation of phosphorylated mammalian target of rapamycin

SCOPE

Conjugated linoleic acids (CLAs) are dietary components with beneficial effects on human health. The aim of this study was to evaluate the potential benefits of CLA pretreatment in a rat model of renal ischemia/reperfusion injury (IRI).

METHODS AND RESULTS

Animals were treated with CLAs (200 mg/kg/day) or water for two weeks prior to sham surgery or to surgery to induce IRI. Renal function, oxidative stress, apoptosis, and cell proliferation markers, were evaluated. Moreover, kidney sections were submitted to histological evaluation. IRI induced increased serum creatinine, blood urea nitrogen, fractional sodium excretion, malondialdehyde, Bax, and phosphorylated mammalian target of rapamycin (P-mTOR), and decreased clearance of creatine, superoxide dismutase and catalase activities, and Bax in comparison with control groups. CLA prefeeding restored, at least in part, the above reported markers to normal levels, increased the anti-apoptotic protein, B-cell lymphoma 2 (Bcl-2), and reduce the histological damage.

CONCLUSION

The results suggest that the decreased renal tissue damage and improved renal function and oxidative stress, in rats pretreated with CLAs before renal IRI induction, could be associated with downregulation of Bax and P-mTOR, and upregulation of Bcl-2. CLAs pretreatment resulted to protect against IRI through the regulation of signaling pathways involved in apoptosis.

Tanshinone IIA pretreatment attenuates ischemia/reperfusion-induced renal injury

Tanshinone IIA is a chemical compound extracted from the root of traditional Chinese herb Salvia miltiorrhiza Bunge. Tanshinone IIA has been suggested to possess anti-inflammatory activity and antioxidizing capability. Recently, accumulating results have indicated the antitumor activity of tanshinone IIA; thus, it has attracted increasing attention. In addition, tanshinone IIA has been indicated to attenuate ischemia/reperfusion induced renal injury (I/RIRI); however, little is known regarding the underlying mechanisms involved in this process. In the present study an I/RIRI rat model was used to analyze the effects of tanshinone IIA on myeloperoxidase (MPO), TNF-α and IL-6 activities using ELISA kits. Furthermore, macrophage migration inhibitory factor (MIF), cleaved caspase-3, B-cell lymphoma 2 (Bcl-2) and p38 mitogen-activated protein kinase (MAPK) protein expression levels were evaluated using western blot analysis. The results indicated that tanshinone IIA protected renal function in I/RIRI rats. ELISA demonstrated that tanshinone IIA significantly reduced MIF, TNF-α and IL-6 activities in I/RIRI rats. Western blot analysis showed that tanshinone IIA significantly suppressed MIF, cleaved caspase-3 and p38 MAPK protein expression levels in I/RIRI rats. The present results suggest that tanshinone IIA pretreatment attenuates I/RIRI via the downregulation of MPO expression, inflammation, MIF, cleaved caspase-3 and p38 MAPK.

Effect of ukrain on ischemia/reperfusion-induced kidney injury in rats

BACKGROUND

The aim of this study was to investigate the potential protective effect of ukrain on an experimental kidney injury model induced by ischemia and reperfusion (IR) in rats.

MATERIAL AND METHODS

A total of 24 male Sprague-Dawley rats were equally and randomly separated into three groups as follows: group-1: controls (C; only laparotomy); group 2: renal ischemia-reperfusion (IR; occlusion of the renal artery for 30 min and 2 h of reperfusion); and group 3: ukrain treatment and IR applied group (U + IR; occlusion of the renal artery for 30 min and 2 h of reperfusion; ukrain was intraperitoneally administered 1 h before the IR process).

RESULTS

Serum total oxidant status (TOS) and total antioxidant status (TAS) levels were measured. The oxidative stress index was determined by calculating the TOS/TAS ratio. TAS serum levels significantly increased, and TOS serum levels also prominently decreased in U + IR group, when compared with the IR group (P < 0.001). Mean NGAL level was remarkably higher in IR group, when compared with the U + IR group (P < 0.001). Caspase-3 messenger RNA (mRNA) expression level increased in IR and decreased in U + IR group (P < 0.001). Bcl-xL serum and mRNA expression levels increased in the U + IR group (P < 0.001). In addition, serum iNOS and mRNA expression levels increased in IR group and decreased in U + IR group (P < 0.001).

CONCLUSIONS

Data established from the present study suggest that ukrain may exhibit protective effect against IR-induced kidney injury and that antioxidant activity primarily modulates this effect.

Soy-Based Multiple Amino Acid Oral Supplementation Increases the Anti-Sarcoma Effect of Cyclophosphamide

The use of a mixture of amino acids caused a selective apoptosis induction against a variety of tumor cell lines, reduced the adverse effects of anti-cancer drugs and increased the sensitivity of tumor cells to chemotherapeutic agents. We evaluated the effects and underlying mechanisms of soy-derived multiple amino acids' oral supplementation on the therapeutic efficacy of low-dose cyclophosphamide (CTX) and on tumor growth, apoptosis, and autophagy in severe combined immunodeficiency (SCID) mice that were injected with sarcoma-180 (S-180) cells. 3-methyladenine or siRNA knockdown of Atg5 was used to evaluate its effect on sarcoma growth. A comparison of mice with implanted sarcoma cells, CTX, and oral saline and mice with implanted sarcoma cells, CTX, and an oral soy-derived multiple amino acid supplement indicated that the soy-derived multiple amino acid supplement significantly decreased overall sarcoma growth, increased the Bax/Bcl-2 ratio, caspase 3 expression, and apoptosis, and depressed LC3 II-mediated autophagy. Treatment with 3-methyladenine or Atg5 siRNA elicited similar responses as CTX plus soy-derived multiple amino acid in downregulating autophagy and upregulating apoptosis. A low dose of CTX combined with an oral soy-derived multiple amino acid supplement had a potent anti-tumor effect mediated through downregulation of autophagy and upregulation of apoptosis.

Transduced Heme Oxygenase-1 Fusion Protein Reduces Renal Ischemia/Reperfusion Injury Through Its Antioxidant and Antiapoptotic Roles in Rats

INTRODUCTION

Heme oxygenase-1 (HO-1) has a protective role against ischemia/reperfusion (I/R) injury.

METHODS

We produced an HO-1 fusion protein mediated by cell penetrated peptide PEP-1, also known as PEP-1-HO-1 fusion protein, and investigated its role in renal I/R injury in rats. Male Sprague-Dawley rats were subjected to 45 minutes of ischemia by occluding the bilateral renal arteries and 6 hours of reperfusion to prepare the model of renal I/R. Animals were randomized to receive PEP-1-HO-1 fusion protein or equal volume of physiologic saline 30 minutes before ischemia.

RESULTS

Administration of PEP-1-HO-1 fusion protein resulted in a significant increase in HO-1 expression. His-probe expression (1 part of the PEP-1-HO-1 fusion protein) was only observed in PEP-1-HO-1-treated animals. I/R caused renal dysfunction and increases in malondialdehyde level and cell apoptosis, and decreased superoxide dismutase activity. Treatment of PEP-1-HO-1 fusion protein reversed these changes. Furthermore, administration of PEP-1-HO-1 inhibited the I/R-induced increase in nuclear factor-κB activation.

CONCLUSIONS

These findings suggest that transduction of PEP-1-HO-1 attenuates renal I/R injury in rats, which might be partly attributable to its antioxidant and antiapoptotic effects.

Optimization of renal transfection using a renal suction-mediated transfection method in mice

BACKGROUND

We previously developed a suction-mediated transfection method in mice.

PURPOSE

The purpose of this study was to optimize the suction-mediated transfection conditions using a pressure-controlled computer system for efficient and safe kidney-targeted gene delivery in mice.

METHODS

Naked pCMV-Luc was injected into the tail vein in mice, and then the right kidney was suctioned by a device of the suction pressure-controlled system. The effects of renal transfection conditions, such as the suction pressure degree, suction pressure waveform and device area were evaluated by measuring luciferase expression. In addition, renal injury was examined.

RESULTS

The renal suction-mediated transfection method at -30 kPa showed high transgene expression. The renal suction waveform did not affect the transfection activity. Under the optimized conditions, the high transgene expression was mostly observed at the renal suctioned site. The transfection conditions used did not induce histological defects or increases in two renal injury biomarkers (Kidney injury molecule-1 mRNA and Clusterin mRNA).

DISCUSSION AND CONCLUSION

We have clarified the transfection conditions for efficient and safe transfection in the kidney using the suction-mediated transfection method in mice.

Hepcidin Mitigates Renal Ischemia-Reperfusion Injury by Modulating Systemic Iron Homeostasis

Iron-mediated oxidative stress is implicated in the pathogenesis of renal ischemia-reperfusion injury. Hepcidin is an endogenous acute phase hepatic hormone that prevents iron export from cells by inducing degradation of the only known iron export protein, ferroportin. In this study, we used a mouse model to investigate the effect of renal ischemia-reperfusion injury on systemic iron homeostasis and determine if dynamic modulation of iron homeostasis with hepcidin has therapeutic benefit in the treatment of AKI. Renal ischemia-reperfusion injury induced hepatosplenic iron export through increased ferroportin expression, which resulted in hepatosplenic iron depletion and an increase in serum and kidney nonheme iron levels. Exogenous hepcidin treatment prevented renal ischemia-reperfusion-induced changes in iron homeostasis. Hepcidin also decreased kidney ferroportin expression and increased the expression of cytoprotective H-ferritin. Hepcidin-induced restoration of iron homeostasis was accompanied by a significant reduction in ischemia-reperfusion-induced tubular injury, apoptosis, renal oxidative stress, and inflammatory cell infiltration. Hepcidin -: deficient mice demonstrated increased susceptibility to ischemia-reperfusion injury compared with wild-type mice. Reconstituting hepcidin-deficient mice with exogenous hepcidin induced hepatic iron sequestration, attenuated the reduction in renal H-ferritin and reduced renal oxidative stress, apoptosis, inflammation, and tubular injury. Hepcidin-mediated protection was associated with reduced serum IL-6 levels. In summary, renal ischemia-reperfusion injury results in profound alterations in systemic iron homeostasis. Hepcidin treatment restores iron homeostasis and reduces inflammation to mediate protection in renal ischemia-reperfusion injury, suggesting that hepcidin-ferroportin pathway holds promise as a novel therapeutic target in the treatment of AKI.

TRPM7 inhibitor carvacrol protects brain from neonatal hypoxic-ischemic injury

BACKGROUND

Our previous study found that suppression of TRPM7 reduced neuronal death in adult rat ischemic brain injury. It was reported that carvacrol blocked TRPM7 and attenuated brain injury in an adult rat MCAO model. The effects of carvacrol on neonatal stroke remain unknown. This study investigated the effects of carvacrol on neuronal injury and behavioral impairment after hypoxia-ischemia in neonatal mice and the potential signaling pathway underlying these effects.

RESULTS

Carvacrol inhibited TRPM7 current in HEK293 cells over-expressing TRPM7 and TRPM7-like current in hippocampal neurons in a dose-dependent manner. Carvacrol (>200 μM) reduced OGD-induced neuronal injury in cortical neurons. 24 hours after HI, TRPM7 protein level in the ipsilateral hemisphere was significantly higher than in the contralateral hemisphere. Carvacrol (30 and 50 mg/kg) pre-treatment reduced brain infarct volume 24 hours after HI in a dose-dependent manner. Carvacrol pre-treatment also improved neurobehavioral outcomes. Furthermore, animals pre-treated with carvacrol had fewer TUNEL-positive cells in the brain compared to vehicle-treated animals 3 days after HI. Carvacrol pre-treatment also increased Bcl-2/Bax and p-Akt/t-Akt protein ratios and decreased cleaved caspase-3 protein expression 24 hours after HI.

CONCLUSIONS

Carvacrol pre-treatment protects against neonatal hypoxic-ischemic brain injury by reducing brain infarct volume, promoting pro-survival signaling and inhibiting pro-apoptotic signaling, as well as improving behavioral outcomes. The neuroprotective effect may be mediated by the inhibition of TRPM7 channel function. Carvacrol is a potential drug development target for the treatment of neonatal stroke.

Targeted deletion of p53 in the proximal tubule prevents ischemic renal injury

The contribution of p53 to kidney dysfunction, inflammation, and tubular cell death, hallmark features of ischemic renal injury (IRI), remains undefined. Here, we studied the role of proximal tubule cell (PTC)-specific p53 activation on the short- and long-term consequences of renal ischemia/reperfusion injury in mice. After IRI, mice with PTC-specific deletion of p53 (p53 knockout [KO]) had diminished whole-kidney expression levels of p53 and its target genes, improved renal function, which was shown by decreased plasma levels of creatinine and BUN, and attenuated renal histologic damage, oxidative stress, and infiltration of neutrophils and macrophages compared with wild-type mice. Notably, necrotic cell death was attenuated in p53 KO ischemic kidneys as well as oxidant-injured p53-deficient primary PTCs and pifithrin-α-treated PTC lines. Reduced oxidative stress and diminished expression of PARP1 and Bax in p53 KO ischemic kidneys may account for the decreased necrosis. Apoptosis and expression of proapoptotic p53 targets, including Bid and Siva, were also significantly reduced, and cell cycle arrest at the G2/M phase was attenuated in p53 KO ischemic kidneys. Furthermore, IRI-induced activation of TGF-β and the long-term development of inflammation and interstitial fibrosis were significantly reduced in p53 KO mice. In conclusion, specific deletion of p53 in the PTC protects kidneys from functional and histologic deterioration after IRI by decreasing necrosis, apoptosis, and inflammation and modulates the long-term sequelae of IRI by preventing interstitial fibrogenesis.

TRPM2 mediates ischemic kidney injury and oxidant stress through RAC1

Ischemia is a leading cause of acute kidney injury. Kidney ischemia is associated with loss of cellular ion homeostasis; however, the pathways that underlie ion homeostasis dysfunction are poorly understood. Here, we evaluated the nonselective cation channel transient receptor potential melastatin 2 (TRPM2) in a murine model of kidney ischemia/reperfusion (I/R) injury. TRPM2-deficient mice were resistant to ischemic injury, as reflected by improved kidney function, reduced histologic damage, suppression of proapoptotic pathways, and reduced inflammation. Moreover, pharmacologic TRPM2 inhibition was also protective against I/R injury. TRPM2 was localized mainly in kidney proximal tubule epithelial cells, and studies in chimeric mice indicated that the effects of TRPM2 are due to expression in parenchymal cells rather than hematopoietic cells. TRPM2-deficient mice had less oxidative stress and lower levels of NADPH oxidase activity after ischemia. While RAC1 is a component of the NADPH oxidase complex, its relation to TRPM2 and kidney ischemic injury is unknown. Following kidney ischemia, TRPM2 promoted RAC1 activation, with active RAC1 physically interacting with TRPM2 and increasing TRPM2 expression at the cell membrane. Finally, inhibition of RAC1 reduced oxidant stress and ischemic injury in vivo. These results demonstrate that TRPM2-dependent RAC1 activation increases oxidant stress and suggest that therapeutic approaches targeting TRPM2 and/or RAC1 may be effective in reducing ischemic kidney injury.

Deep-sea water containing selenium provides intestinal protection against duodenal ulcers through the upregulation of Bcl-2 and thioredoxin reductase 1

Deep-sea water (DSW), which is rich in micronutrients and minerals and with antioxidant and anti-inflammatory qualities, may be developed as marine drugs to provide intestinal protection against duodenal ulcers. We determined several characteristics in the modified DSW. We explored duodenal pressure, oxygenation, microvascular blood flow, and changes in pH and oxidative redox potential (ORP) values within the stomach and duodenum in response to tap water (TW, hardness: 2.48 ppm), DSW600 (hardness: 600 ppm), and DSW1200 (hardness: 1200 ppm) in Wistar rats and analyzed oxidative stress and apoptosis gene expressions by cDNA and RNA microarrays in the duodenal epithelium. We compared the effects of drinking DSW, MgCl₂, and selenium water on duodenal ulcers using pathologic scoring, immunohistochemical analysis, and Western blotting. Our results showed DSW has a higher pH value, lower ORP value, higher scavenging H₂O₂ and HOCl activity, higher Mg²⁺ concentrations, and micronutrients selenium compared with TW samples. Water infusion significantly increased intestinal pressure, O₂ levels, and microvascular blood flow in DSW and TW groups. Microarray showed DSW600, DSW1200, selenium water upregulated antioxidant and anti-apoptotic genes and downregulated pro-apoptotic gene expression compared with the TW group. Drinking DSW600, DSW1200, and selenium water but not Mg²⁺ water significantly enhanced Bcl-2 and thioredoxin reductase 1 expression. Bax/Bcl-2/caspase 3/poly-(ADP-ribose)-polymerase signaling was activated during the pathogenesis of duodenal ulceration. DSW drinking reduced ulcer area as well as apoptotic signaling in acetic acid-induced duodenal ulcers. DSW, which contains selenium, provides intestinal protection against duodenal ulcers through the upregulation of Bcl-2 and thioredoxin reductase 1.

Augmented renal prostacyclin by intrarenal bicistronic cyclo-oxygenase-1/prostacyclin synthase gene transfer attenuates renal ischemia-reperfusion injury

BACKGROUND

We elucidated the protective mechanism of increased prostacyclin (PGI2) derived from adenoviral cyclo-oxygenase (COX)-1/prostacyclin synthase (PGIS) (Adv-COPI) gene transfer in rat kidneys with ischemia-reperfusion (I/R) injury.

METHODS

We tended to augment PGI2 production by intrarenal arterial Adv-COPI administration with renal venous clamping in female Wistar rats. After Adv-COPI transfection, we evaluated the renal COX-1 and PGIS protein expression and PGI2 and prostaglandin E2 (PGE2) levels in the kidney and renal venous plasma. We evaluated the protective effect of PGI2 on hypoxia/reoxygenation-induced tubular cells injury or I/R kidneys by measuring oxidative stress, necrosis, apoptosis, and autophagy in tubules and kidneys and determining renal function, microcirculation, and accumulation of tubular 4-hydroxynonenal in the kidney in vivo.

RESULTS

Adv-COPI treatment selectively augmented COX-1 and PGIS protein expression in the renal proximal and distal tubules and significantly increased PGI2, not PGE2, production in the renal venous plasma and kidney at the baseline level. I/R markedly depressed renal blood flow and increased the production in O2, PGE2, the expression in P47 and Rac-1 expression of two nicotinamide adenine dinucleotide phosphate oxidase subunits, cytosolic cytochrome C release, proapoptotic marker lamin expression, the pathologic appearance of necrosis, apoptosis, and autophagy, and blood urea nitrogen and creatinine levels in the damaged kidneys. Adv-COPI protected distal and proximal tubules against hypoxia/reoxygenation-enhanced oxidative stress and autophagic, apoptotic, and necrotic cell death. Adv-COPI significantly improved renal function by restoring renal blood flow, reducing nicotinamide adenine dinucleotide phosphate oxidase-derived and mitochondria-derived oxidative stress, and necrosis, apoptosis, and autophagy.

CONCLUSIONS

Increased PGI2 by Adv-COPI protects the kidney against I/R-induced oxidative stress, necrosis, apoptosis and autophagy.

Progressive thermopreconditioning attenuates rat cardiac ischemia/reperfusion injury by mitochondria-mediated antioxidant and antiapoptotic mechanisms

OBJECTIVES

Progressive thermal preconditioning (PTP) provides vascular protection with less hemodynamic fluctuations, endoplasmic reticulum (ER), and oxidative stress compared with whole body hyperthermia. We suggest PTP might efficiently diminish cardiac ischemia/reperfusion-induced apoptosis and autophagy injury.

METHODS

A total of 67 male Wistar rats were divided into a non-PTP control group, 24 or 72 hours after a single cycle or 3 consecutive cycles of PTP in a 42°C water bath (1-24, 1-72, 3-24, and 3-72 groups). We measured the cardiac O2(-) amount in vivo in response to left anterior descending coronary artery ligation for 2 hours and reperfusion for 3 hours. Cardiac function and injury were determined by microcirculation, electrocardiography, and infarct size. The PTP-induced protective effects on nicotinamide adenine dinucleotide phosphate oxidase gp91-mediated oxidative stress, ER stress, and apoptosis- and autophagy-related mechanisms were examined using Western blot and immunohistochemistry.

RESULTS

Coronary arterial ischemia/reperfusion depressed cardiac microcirculation, induced ST-segment elevation and increased infarct size in non-PTP and PTP rats. Ischemia/reperfusion enhanced the cardiac O2(-) levels by enhanced nicotinamide adenine dinucleotide phosphate oxidase gp91 expression, cytosolic cytochrome C release, and decreased mitochondrial Bcl-2 expression. Cardiac injury activated ER stress-78-kDa glucose-regulated protein expression, increased the Bax/Bcl-2 ratio, cleaved caspase 3 expression and poly-(ADP-ribose)-polymerase fragments, leading to apoptosis formation, and promoted LC3-II expression, resulting in autophagy formation. PTP treatment elevated heat shock protein 70, heat shock protein 32, Bcl-2, Bcl-xL, and manganese superoxide dismutase in the rat heart, especially in the 3-72 group. PTP treatment significantly restored cardiac microcirculation, decreased oxidative stress, ER stress, apoptosis, autophagy, and infarct size.

CONCLUSIONS

PTP significantly reduced cardiac ischemia/reperfusion injury by upregulating antioxidant, antiapoptotic, and antiautophagic mechanisms.

Osthole ameliorates renal ischemia-reperfusion injury by inhibiting inflammatory response

INTRODUCTION

Renal ischemia-reperfusion (I/R) injury is a primary cause of acute renal failure that results in high mortality. This study aimed to investigate the effect of osthole, a natural coumarin derivative, on renal I/R injury in a rat model.

MATERIALS AND METHODS

Rats were randomly allocated to the sham operation + vehicle, I/R + vehicle, and I/R + osthole groups. Renal I/R injury was induced by clamping the left renal artery for 45 min followed by 12 h of reperfusion and a contralateral nephrectomy. Osthole (40 mg/kg) was intraperitoneally injected 30 min before inducing I/R. Renal function and histological damage were determined subsequently. Myeloperoxidase activity, monocyte/macrophage infiltration, as well as tumor necrosis factor-α, IL-1β, and activated p38 mitogen-activated protein kinase expression in kidneys were also assessed.

RESULTS

Osthole treatment significantly ameliorated I/R-induced renal functional and morphological injuries. Moreover, osthole treatment attenuated myeloperoxidase activity, monocyte/macrophage infiltration, and tumor necrosis factor-α, IL-1β, and activated p38 mitogen-activated protein kinase expression in kidneys.

CONCLUSIONS

Osthole treatment ameliorates renal I/R injury by inhibiting inflammatory responses in kidneys. Thus, osthole may represent a novel practical strategy to prevent renal I/R injury.

Berberine protects human renal proximal tubular cells from hypoxia/reoxygenation injury via inhibiting endoplasmic reticulum and mitochondrial stress pathways

Background

Ischemia/reperfusion injury plays a crucial role in renal transplantation, and represents a significant risk factor for acute renal failure and delayed graft function. The pathophysiological contribution of endoplasmic reticulum and mitochondria stress to ischemia/reperfusion injury has also been highlighted. Berberine (BBR) has been showed to attenuate ischemia/reperfusion injury by inhibiting oxidative stress. The study was carried out to investigate whether the pretreatment of BBR could reduce hypoxia/reoxygenation (H/R)-induced injury by inhibiting mitochondria stress and endoplasmic reticulum stress pathways.

Methods

The cultured human renal proximal tubular cell line HK-2 cells were exposed to 24 h hypoxia (5% CO₂, 1% O₂, 94% N₂) followed by 3 h reoxygenation (5% CO₂, 21% O₂, 74% N₂). And BBR was added to the culture medium 2h prior to the treatment. Then the cell viability, oxidative stress level, morphological change of apoptosis and apoptotic rate were determined. In addition, Western blot analysis was performed to identify the expression of apoptotic pathway parameters, including Bcl-2, Bax and cytochrome C involved in mitochondrial-dependent pathway and ER stress hallmarks such as glucose-regulated protein 78 and CCAAT/enhancer binding protein homologous protein.

Results

H/R produced dramatic injuries in HK-2 cells. The cell viability and the oxidative stress level in group H/R was significantly decreased. The classical morphological change of apoptosis was found, while the apoptotic rate and the expression of proteins involved in mitochondrial stress and endoplasmic reticulum stress pathways increased (p<0.05). Administration of BBR significantly inhibited these H/R induced changes (p<0.05).

Conclusion

This study revealed that BBR pretreatment serves a protective role against H/R induced apoptosis of human renal proximal tubular cells, and the mechanism is related to suppression of mitochondrial stress and endoplasmic reticulum stress pathways.