Wenli Yu

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

BackgroundIschemia/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.MethodsThe 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.ResultsH/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).ConclusionThis 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.

Protective Effect of Berberine Pretreatment in Hepatic Ischemia/Reperfusion Injury of Rat

BACKGROUNDnBerberine (BBR) has been demonstrated to protect against hepatic ischemia/reperfusion (I/R) injury. However, the exact mechanism is largely unknown. In the present study, we examined the role of phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) and mammalian target of rapamycin (mTOR) in the protective effect of BBR on hepatic I/R-mediated apoptosis in rats.nnnMETHODSnAdult male Sprague-Dawley rats were assigned randomly to groups of sham, ischemia/reperfusion (I/R), I/R+DMSO (vehicle) and I/R+BBR (100 mg/kg/d, 2 weeks). The hepatic cold ischemia model was established by perfusing the liver with heparinized cold saline through the portal vein for 20 minutes. The liver function and oxidative stress level were measured by biochemical and histopathologic examinations. The apoptotic rate was determined by terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) assay. The expression of Bcl-2, Bax, caspase-3, and the phosphorylation of Akt and mTOR were assayed by Western blot analysis and immunohistochemistry.nnnRESULTSnCompared with the I/R group, BBR dramatically attenuated the histopathologic damage, restored the liver function, and decreased the oxidative stress level. Simultaneously, BBR significantly ameliorated apoptosis by decreasing the apoptotic rate, increasing the Bcl-2/Bax ratio and inhibiting cleaved caspase-3 expression in rats subjected to hepatic I/R. The expression of p-Akt were effectively upregulated with the inhibited expression of p-mTOR.nnnCONCLUSIONnOur study reveals that BBR preconditioning protects against hepatic I/R partly by reducing apoptosis, which is possibly involved with the modulation of the PI3K/Akt/mTOR signaling pathway.

Vitexin suppresses autophagy to induce apoptosis in hepatocellular carcinoma via activation of the JNK signaling pathway

Vitexin, a flavonoids compound, is known to exhibit broad anti-oxidative, anti-inflammatory, analgesic, and antitumor activity in many cancer xenograft models and cell lines. The purpose of this study was to investigate the antitumor effects and underlying mechanisms of vitexin on hepatocellular carcinoma. In this study, we found that vitexin suppressed the viability of HCC cell lines (SK-Hep1 and Hepa1-6 cells) significantly. Vitexin showed cytotoxic effects against HCC cell lines in vitro by inducing apoptosis and inhibiting autophagy. Vitexin induced apoptosis in a concentration-dependent manner, and caused up-regulations of Caspase-3, Cleave Caspase-3, and a down-regulation of Bcl-2. The expression of autophagy-related protein LC3 II was significantly decreased after vitexin treatment. Moreover, western blot analysis presented that vitexin markedly up-regulated the levels of p-JNK and down-regulated the levels of p-Erk1/2 in SK-Hep1 cells and Hepa1-6 cells. Cotreatment with JNK inhibitor SP600125, we demonstrated that apoptosis induced by vitexin was suppressed, while the inhibition of autophagy by vitexin was reversed. The results of colony formation assay and mouse model confirmed the growth inhibition role of vitexin on HCC in vitro and in vivo. In conclusion, vitexin inhibits HCC growth by way of apoptosis induction and autophagy suppression, both of which are through JNK MAPK pathway. Therefore, vitexin could be regarded as a potent therapeutic agent for the treatment of HCC.

Berberine protects against ischemia/reperfusion injury after orthotopic liver transplantation via activating Sirt1/FoxO3α induced autophagy

The effects and mechanism of berberine (BBR) on hepatic injury after orthotopic liver transplantation (OLT) have not been well characterized. We examined the role of Sirt1/FoxO3α axis in the protective effect of BBR on ischemia/reperfusion injury after OLT. Adult male Wistar rats were randomly allocated into four groups: Sham, OLT, OLT with BBR pretreatment (BBR), OLT with BBR and Sirt1 inhibitor (EX527) pretreatment group (EX527). The liver function and oxidative stress level were measured by biochemical and histopathologic examinations. The formation of autophagosome was observed by transmission electron microscopy. The apoptotic rate was determined by TUNEL analysis and the apoptotic mRNA expression. The expression of Sirt1, FoxO3α, Beclin-1, LC3-II/LC3-I, p62 and the acetylation of FoxO3α were assayed by western blot assay and immunoprecipitation. Compared with the OLT group, BBR dramatically attenuated the histopathologic damage, restored the liver function, and decreased the oxidative stress level. Simultaneously, BBR significantly ameliorated apoptosis by decreasing the apoptotic rate and the expression of apoptotic mRNA in rats subjected to OLT. The level of Beclin-1 and LC3-II/LC3-I were upregulated with the inhibition of p62. The deacetylation of FoxO3α by Sirt1 was enhanced in the nuclear of liver after pretreated with BBR. However, the inhibition of Sirt1 by EX527 counteracted the protective effects of BBR. Thus, BBR preconditioning promotes liver transplant ischemia/reperfusion injury partly via activating Sirt1/FoxO3α mediated autophagy.

Propofol postconditioning attenuates hippocampus ischemia-reperfusion injury via modulating JAK2/STAT3 pathway in rats after autogenous orthotropic liver transplantation.

Liver transplantation has been a routine treatment for the end stage liver diseases. Severe changes in circulation system and internal environment may occur during transplant surgery and cause injury to many organs including brain. Specific mechanisms of brain injury associated with liver transplantation are not yet elucidated. Previous studies have shown that the JAK/STAT signal transduction pathways are involved in the development of the central nervous system, such as nerve cell proliferation, survival, differentiation, and it also have a role in the disease processes, including brain tumor, brain ischemia and other diseases of the central nervous system. In this study we investigate whether propofol plays an important role in protecting the hippocampus through JAK2/STAT3 pathway. Thirty-two healthy male Sprague-Dawley rats, were randomly divided into four groups (n=8). Sham operation group (group S), autogenous orthotropic liver transplantation group (group I), autogenous orthotropic liver transplantation+propofol treatment group (group P) and autogenous orthotropic liver transplantation+propofol+AG490 treatment group (group A). We evaluated histological damage, inflammation, oxidative stress and apoptosis in hippocampus using HE staining, light microscope, real-time PCR and western blot. The results showed that there was a significant damage of hippocampus in group I compared to the sham group as demonstrated by increased serum levels of S100β, NSE and the histological changes. However, an induction of propofol reduced the levels of MDA, TNFα, S100β, NSE and increased activity of SOD, IL-10, and attenuated the expression of JAK2 and STAT3, meanwhile. Consistently, pretreatment with JAK2/STAT3 pathway inhibitor AG490, decreased the levels of MDA, TNFα, S100β, NSE and increased activity of SOD, IL-10, and attenuated the expression of JAK2 and STAT3. These results reveal that autogenous orthotropic liver transplantation induces the activation of JAK2/STAT3 signaling pathway in hippocampus. Pretreatment with propofol attenuates autogenous orthotropic liver transplantation induces hippocampal injury via JAK2/STAT3 pathway.

Hydrogen-Rich Saline Attenuates Acute Kidney Injury After Liver Transplantation via Activating p53-Mediated Autophagy.

Background Acute kidney injury (AKI) impacts the survival of liver transplant recipients severely. To date, the related mechanism and effective therapy have not been rigorously explored. The present study aimed to explore the role of p53-mediated autophagy in the protective effect of hydrogen-rich saline (HRS) on AKI after orthotropic liver transplantation (OLT). Methods Adult male Sprague-Dawley rats were randomly allocated into four groups: sham, OLT, OLT with HRS (6 ml/kg) pretreatment (HS), OLT with HRS and chloroquine pretreatment (60 mg/kg) group (CQ). All the samples were collected 6 hours after reperfusion. The renal function and oxidative stress level were measured by biochemical and histopathologic examinations. The formation of autophagosome was observed by transmission electron microscopy. The apoptotic rate was determined by terminal deoxynucleotide transferase-mediated deoxyuridine triphosphate nick-end labeling analysis. The expression of caspase-3, cytochrome c, p53, damage-regulated autophagy modulator, Becline-1, microtubule-associated protein light 3-II, p62, lysosome-associated membrane protein-2, and the phosphorylation of p53 were assayed by western blot assay. Results Compared with the OLT group, HRS dramatically attenuated the histopathologic damage, restored the renal function, and decreased the oxidative stress level. Simultaneously, HRS significantly ameliorated apoptosis by decreasing the apoptotic rate and inhibiting the expression of caspase-3 and cytochrome c in rats subjected to OLT. The expression of Becline-1 and microtubule-associated protein light 3-II were upregulated with the inhibition of p62 and lysosome-associated membrane protein-2. The inhibition of autophagy by chloroquine counteracted the renoprotective effects of HRS. Conclusions HRS is able to protect against AKI after liver transplantation partly by reducing apoptosis, which is possibly involved in the modulation of p53-mediated autophagy.

Interferon regulatory factor-1 activates autophagy to aggravate hepatic ischemia-reperfusion injury via the P38/P62 pathway in mice

Increasing evidence has linked autophagy to a detrimental role in hepatic ischemia- reperfusion (IR) injury (IRI). Here we focus on the role of interferon regulatory factor-1 (IRF-1) in regulating autophagy to aggravate hepatic IRI. We found that IRF-1 was up-regulated during hepatic IRI and was associated with an activation of the autophagic signaling. This increased IRF-1 expression, which was allied with high autophagic activity, amplified liver damage to IR, an effect which was abrogated by IRF-1 depletion. Moreover, IRF-1 contributed to P38 induced autophagic and apoptotic cell death, that can play a key role in liver dysfunction. The levels of P62 mRNA and protein were increased when P38 was activated and decreased when P38 was inhibited by SB203580. We conclude that IRF-1 functioned as a trigger to activate autophagy via P38 activation and that P62 was required for this P38-mediated autophagy. IRF-1 appears to exert a pivotal role in hepatic IRI, by predisposing hepatocytes to activate an autophagic pathway. Such an effect promotes autophagic cell death through the P38/P62 pathway. The identification of this novel pathway, that links expression levels of IRF-1 with autophagy, may provide new insights for the generation of novel protective therapies directed against hepatic IRI.

CXCL13 regulates the trafficking of GluN2B-containing NMDA receptor via IL-17 in the development of remifentanil-induced hyperalgesia in rats

BACKGROUNDnThis study aimed to investigate whether CXCL13 modulated the trafficking of NMDA receptor via interleukin (IL)-17 in a rat model of remifentanil-induced hyperalgesia (RIH).Although chemokines are crucial regulators of neuroinflammation, spinal N-methyl-d-aspartate (NMDA) receptor activation, and development of hypernociceptive process, little is known about specific pathogenesis and effective treatment. Inflammatory mediators are required for excitatory synaptic transmission in pathologic pain.nnnMETHODSnA neutralizing antibody against CXCL13 (anti-CXCL13), antiserum against IL-17 (anti-IL-17), and recombinant CXCL13 and IL-17 were administered intrathecally to explore the roles of CXCL13, IL-17, and NMDA receptor, as well as the prevention of hyperalgesia. Paw withdrawal threshold and paw withdrawal latency were employed to record mechanical allodynia and thermal hyperalgesia. Reverse transcriptase quantitative polymerase chain reaction was used to evaluate the levels of CXCL13/CXCR5 and IL-17/IL-17RA in the spinal dorsal horn. The trafficking of spinal GluN2B-containing NMDA receptor was assessed by Western blot after nociceptive testing.nnnRESULTSnThis study found mechanical allodynia and thermal hyperalgesia with a remarkable increase in the expression of spinal CXCL13/CXCR5 and IL-17/IL-17RA and trafficking of GluN2B-containing NMDA receptor after remifentanil exposure. Behavioral RIH and elevated GluN2B trafficking were dampened by intrathecal anti-CXCL13 and anti-IL-17, respectively. The delivery of exogenous CXCL13 dose-dependently generated a rapid nociceptive hypersensitivity in naïve rats, which was prevented by coadministering anti-IL-17. CXCL13-induced IL-17RA overproduction and GluN2B trafficking were reversed by anti-IL-17 treatment. GluN2B antagonist also blocked CXCL13, and IL-17 directly induced hyperalgesia.nnnCONCLUSIONnThis study highlighted the contribution of IL-17 pathway in the trafficking of CXCL13-induced GluN2B-containing NMDA receptor in the pathogenesis of RIH.

Dexmedetomidine ameliorates the inflammatory immune response in rats with acute kidney damage

It has been demonstrated that dexmedetomidine (Dex) can protect patients with acute kidney injury from experiencing further tissue damage, however its mechanism of action remains unclear. The present study investigated the immune modulatory functions of Dex in rats with acute kidney injury (AKI) induced via injection of lipopolysaccharide into the tail vein. ELISA analysis showed that Dex reduced the levels of inflammatory cytokines in rats with AKI in a dose dependent manner. Furthermore, the regulatory effects of Dex on cytokine production disappeared when the α-2 adrenergic receptor antagonist Yohimbine (YOH) was added. For a detailed investigation on how Dex regulates the immune response in rats with AKI, the impact of Dex on the viability of splenocytes and lymphocytes was determined and it was determined that Dex did not influence splenocyte and lymphocyte viability. In addition, ELISA tests showed that Dex regulated the production of the T-helper (Th) 17 cytokines interleukin (IL)-17 and IL-23, but not the Th1 cytokine tumor necrosis factor α, in splenocytes and lymphocytes. To confirm whether Dex functioned as an α-2-adrenergic receptor in these immune regulations, YOH was administered together with Dex. When Dex and YOH were administered together, the regulatory functions of Dex were reduced, confirming that Dex acted as an agonist on the α-2-adrenergic receptor. Thus the results of the current study may provide novel insights regarding how Dex modulates immune functions in AKI.

Berberine protects renal tubular cells against hypoxia/reoxygenation injury via the Sirt1/p53 pathway

Berberine (BBR) has been demonstrated to protect against renal ischemia/reperfusion injury; however, the underlying molecular mechanism is largely unknown. In the present study, we examined the role of silent information regulator 1 (Sirt1)/p53 in the protective effect of BBR on hypoxia/reoxygenation (H/R)-mediated mitochondrial dysfunction in rat renal tubular epithelial cells (NRK-52E cells). NRK-52E cells were preconditioned with small interfering RNA targeting Sirt1 (Sirt1-siRNA)xa0and BBR before subjected to H/R. Cell damage was assessed by CCK8 assay and detection of oxidative parameters. The apoptotic rate was determined by flow cytometry and Hoechst 33258 staining. The expression of apoptotic markers, Sirt1, p53 and the translocation of p53 were examined by Western blotting assay. Nuclear p53 deacetylation by Sirt1 was detected using immunoprecipitation. Compared with the H/R group, BBR pretreatment increased cell viability and inhibited mitochondrial oxidative stress and apoptosis. Protein expression of Sirt1 was also enhanced along with a reduction of p53. Furthermore, both nuclear translocation of p53 and its acetylation were inhibited in NRK-52E cells pretreated with BBR. However, the knockdown of Sirt1 counteracted the renoprotection of BBR. BBR preconditioning protects rat renal tubular epithelial cells against H/R-induced mitochondrial dysfunction via regulating the Sirt1/p53 pathway.