Quercetin exhibits neuroprotective effect by reduc-ing amyloid precursor protein expression and oxida-tive stress in Neuro2a/APPswe cell model / 中国药理学与毒理学杂志

OBJECTIVE The abnormal amyloid-β(Aβ)and oxidative stress assiociated with the progression of Alzheimer disease(AD).Quercetin has been reported to possess antioxidant and anti-inflammatory properties in neurodegenerative disorders.In this present study,we designed to characterize the mechanisms by which quer-cetin exerts neuroprotective effects in murine neuroblas-toma N2a cells stably expressing human Swedish mutant amyloid precursor protein(N2a/APP).METHODS N2a/APP cells were treated with quercetin at concentrations of 10,20 and 50 μ mol·L-1 for 24 h.Cell viability was examined with CCK-8 assays.The protein levels of ERK1/2 and Akt were detected by Western blotting.Intra-cellular reactive oxygen species(ROS)was detected by a fluorescent probe 2,7-dichlorofluorescein diacetate(DCFH-DA).The mitochondrial membrane potential(Δψ m)in N2a/APP cells was detected by using JC-1 staining method.Immunofluorescence was used to detect the generation of 8-hydroxy-2′-deoxyguanosine(8-OHdG)and 4-hydroxynonenal(4-HNE).RESULTS Quercetin attenuated the enhancement of p-ERK1/2,reductions of p-Akt,and decreased levels of APP expression.More-over,quercetin alleviated loss of mitochondria membrane potential(MMP)since it attenuates these oxidative stress,as reflected in the levels of ROS,4-HNE and 8-OHdG,was elevated in N2a/APP cells and these effects were again ameliorated by quercetin.CONCLUSION Neuroprotection by quercetin in N2a/APP cells involves normalizing the impaired mitochondrial function and reducing oxidative stress via inactivation of the ERK1/2 and activation of the Akt pathways.

Exploring the treatment of sepsis-associated acute lung injury with Liangge Powder via ERK1/2 and PI3K/AKT pathways: based on network pharmacology and whole animal experimentation / 中华劳动卫生职业病杂志

Objective: To investigate the therapeutic effect and mechanism of Liangge Powder against sepsis-induced acute lung injury (ALI) . Methods: From April to December 2021, the key components of Liangge Powder and its targets against sepsis-induced ALI were analyzed by network pharmacology, and to enrich for relevant signaling pathways. A total of 90 male Sprague-Dawley rats were randomly assigned to sham-operated group, sepsis-induced ALI model group (model group), Liangge Powder low, medium and high dose group, ten rats in the sham-operated group and 20 rats in each of the remaining four groups. Sepsis-induced ALI model was established by cecal ligation and puncture. Sham-operated group: gavage with 2 ml saline and no surgical treatment. Model group: surgery was performed and 2 ml saline was gavaged. Liangge Powder low, medium and high dose groups: surgery and gavage of Liangge Powder 3.9, 7.8 and 15.6 g/kg, respectively. To measure the wet/dry mass ratio of rats lung tissue and evaluate the permeability of alveolar capillary barrier. Lung tissue were stained with hematoxylin and eosin for histomorphological analysis. The levels of tumor necrosis factor-alpha (TNF-α), interleukin (IL) -6 and IL-1β in bronchoalveolar lavage fluid (BALF) were measured by enzyme-linked immunosorbent assay. The relative protein expression levels of p-phosphatidylinositol 3-kinase (PI3K), p-protein kinase B (AKT), and p-ertracellular regulated protein kinases (ERK) were detected via Western blot analysis. Results: Network pharmacology analysis indicated that 177 active compounds of Liangge Powder were selected. A total of 88 potential targets of Liangge Powder on sepsis-induced ALI were identified. 354 GO terms of Liangge Powder on sepsis-induced ALI and 108 pathways were identified using GO and KEGG analysis. PI3K/AKT signaling pathway was recognized to play an important role for Liangge Powder against sepsis-induced ALI. Compared with the sham-operated group, the lung tissue wet/dry weight ratio of rats in the model group (6.35±0.95) was increased (P<0.001). HE staining showed the destruction of normal structure of lung tissue. The levels of IL-6 [ (392.36±66.83) pg/ml], IL-1β [ (137.11±26.83) pg/ml] and TNF-α [ (238.34±59.36) pg/ml] were increased in the BALF (P<0.001, =0.001, <0.001), and the expression levels of p-PI3K, p-AKT and p-ERK1/2 proteins (1.04±0.15, 0.51±0.04, 2.31±0.41) were increased in lung tissue (P=0.002, 0.003, 0.005). The lung histopathological changes were reduced in each dose group of Liangge Powder compared with the model group. Compared with the model group, the wet/dry weight ratio of lung tissue (4.29±1.26) was reduced in the Liangge Powder medium dose group (P=0.019). TNF-α level [ (147.85±39.05) pg/ml] was reduced (P=0.022), and the relative protein expression levels of p-PI3K (0.37±0.18) and p-ERK1/2 (1.36±0.07) were reduced (P=0.008, 0.017). The wet/dry weight ratio of lung tissue (4.16±0.66) was reduced in the high-dose group (P=0.003). Levels of IL-6, IL-1β and TNF-α[ (187.98±53.28) pg/ml, (92.45±25.39) pg/ml, (129.77±55.94) pg/ml] were reduced (P=0.001, 0.027, 0.018), and relative protein expression levels of p-PI3K, p-AKT and p-ERK1/2 (0.65±0.05, 0.31±0.08, 1.30±0.12) were reduced (P=0.013, 0.018, 0.015) . Conclusion: Liangge Powder has therapeutic effects in rats with sepsis-induced ALI, and the mechanism may be related to the inhibition of ERK1/2 and PI3K/AKT pathway activation in lung tissue.

Benzopyrene activates ERK1/2 signal pathway to promote extracellular matrix protein deposition of airway smooth muscle cells on airway remodeling / 重庆医学

Objective To investigate the influence of benzopyrene on extracellular matrix(ECM) protein deposition of human airway smooth muscle cells(HASMC) and the related pathway mechanism.Methods HASMC were primarily cultured and the 2-6 generations cells were applied in this experiment.The expression amount of ECM gene and protein was detected by real time PCR and Western Blot the phosphorylation level was analyzed by using the Western Blot method.Results Benzopyrene could to increase the expression of HASMC collagen Ⅰ α1 protein (P＜0.01) and ECM protein (including collagen Ⅰ α1,versican,fibronectin,laminin α2) mRNA(P＜0.05).Benzopyrene could induce the rapid increase of ERK1/2 phosphorylation level (P＜0.01).Furthermore,the ERK pathway inhibitor PD98059 could significantly inhibit the increase of benzopyrene-induced collagen Ⅰ α1 (P＜0.01)and ECM protein(including collagen Ⅰ α1,versican,fibronectin,laminin α2) mRNA expression(P＜0.01).Conclusion Benzopyrene induces the ECM protein deposition of HASMC by activating the ERK1/2 pathway,blocking the ERK1/2 signal pathway can inhibit the benzopyrene-induced airway remodeling.

Angiotensin II regulates catalase expression and promotes fibroblast phe-notype transformation through ERK1/2 pathway / 中国病理生理杂志

AIM:To explore the effect of extracellular signal-regulated kinase 1/2 ( ERK1/2) on the vascular adventitial remodeling in a hypertension rat model .METHODS:The rats were randomly divided into control group , mini-pump infusion of saline group and mini-pump infusion of angiotensin II ( Ang II) group as the hypertension model .The sys-tolic pressure and vascular morphology of the rats were examined .Adventitial fibroblasts were treated with Ang II , PD98059 ( ERK1/2 inhibitor) and Ang II+PD98059.The catalase ( CAT) expression in the cells was detected by Western blotting . RESULTS:Compared with control group and mini-pump infusion of saline group , the systolic pressure and carotid media thickness (stained by HE) in mini-pump infusion of Ang II group were significantly increased (P<0.01).Meanwhile, ar-tery morphology in mini-pump infusion of Ang II group had obviously changed with a significant occurrence of pathological vascular remodeling .The result of Western blotting showed that the expression of CAT in the adventitial fibroblasts treated with Ang II+PD98059 was much higher than that in the cells treated with Ang II alone (P<0.05), indicating that down-regulation of CAT induced by Ang II was restored by ERK 1/2 signaling pathway .CONCLUSION:Ang II down-regulates CAT through ERK1/2 pathway and promotes cell phenotype transformation , which lead to pathological vascular remodeling .

Hypoxia induces myofibroblast formation and stimulates production of collagen Ⅰ in myofibroblasts through ERK1/2 pathway / 中国病理生理杂志

AIM: To investigate the effect of hypoxia on the myofibroblast transdifferentiation from fibroblasts,and associated signaling of hypoxia on the production of collagen Ⅰ in cultured rat renal cortical myofibroblasts.METHODS: The study is composed of two relevant parts.In the first part,a normal rat renal interstitial fibroblast cell line NRK-49F was treated with hypoxia(1% O2) or normoxia(21% O2) for 6 h,12 h and 24 h.The expression of hypoxia inducible factor-1?(HIF-1?) was examined by Western blotting in order to make sure the hypoxic condition is reliable.The myofibroblast transformation from fibroblasts induced by hypoxia was assayed by detecting the protein levels of ?-smooth muscle actin(?-SMA).In the second part,the object was done on the primary cultured rat renal cortical myofibroblasts.Myofibroblasts were subjected to hypoxic or normoxic conditions for variety of times.The levels of HIF-1? in cell lysates and collagen I protein in supernatant culture medium and the activation of extracellular signal-regulated kinase(ERK)1/2 MAPK pathway were analyzed by Western blotting.RT-PCR was carried out to measure the levels of collagen I mRNA at different time points(2 h,4 h and 6 h).The distribution of HIF-1? in myofibroblasts was demonstrated by immunocytochemistry.The changes of collagen I production were detected after PD98059,a specific inhibitor of ERK1/2 activation pretreatment and during the hypoxia incubation.The activity of gelatinase matrix metalloproteinase-2(MMP-2) and MMP-9 in the supernatant medium from the cultured cells were assayed by gelatin zymography.RESULTS: Significant increased levels of HIF-1? protein appeared in cell lysates under hypoxia for 6 h.Furthermore,HIF-1? was translocated into nuclei of myofibroblasts after 6 h exposure of myofibroblasts to hypoxia.The levels of ?-SMA protein increased in NRK-49F under hypoxia for 12 h(187%?32%,P

Role of ERK1/2-STAT3 pathway in adaptive cytoprotection induced by H_2O_2 preconditioning / 中国病理生理杂志

AIM: To explore the role of extracellular signal-regulated kinases ERK1/2-STAT3 pathway in adaptive cytoprotection induced by H2O2 preconditioning in PC12 cells.METHODS: In PC12 cells,the experimental model of cytoprotection by H2O2 preconditioning against oxidative stress-induced injury was set up.The morphological changes in the apoptotic cells were observed by using of chromatin dye Hoechst 33258.The percent of apoptotic cells was determined by flow cytometry(FCM) with propidium iodide staining.The levels of p-ERK1/2 and p-STAT3 expression were detected by Western blotting assay.RESULTS: Preconditioning with H2O2 at concentration of 100 ?mol/L for 90 min obviously inhibited apoptosis induced by 300 ?mol/L H2O2,and both ERK1/2 and STAT3 were activated.UO126(10 ?mol/L,an inhibitor of ERK1/2) or AG-490(10?mol/L,an inhibitor of JAK2) significantly blocked the cytoprotection effect of H2O2 preconditioning.Moreover,UO126(10 ?mol/L) also markedly inhibited the up-regulation of p-STAT3 expression by H2O2 preconditioning.CONCLUSION: H2O2 preconditioning activates ERK1/2-STAT3 signal pathway,which may be one of the mechanisms underlying H2O2 preconditioning-induced cytoprotection.

Effects of oxidized high density lipoprotein on tissue factor expression in ECV304 cell line / 中国病理生理杂志

AIM: To investigate the expression of tissue factor(TF) induced by oxidized high density lipoprotein(oxHDL) in human umbilical vein cell line,ECV304,and the related mechanisms.METHODS: Four main groups were designed: the negative,the positive(ECV304 with histamine),the HDL group and the oxHDL group.Quantitative real-time polymerase chain reaction(RQ-PCR) and Western blotting were used to detect the expression level of TF.The specific inhibitors of MAPKs,SP600125(c-jun terminal NH2 kinase,JNK),SB203580(p38 MAP kinase,p38 MAPK),PD98059(extracellular signal-regulated kinase,ERK1/2) were used to investigate the underlying mechanisms.RESULTS: The TF expression in normal ECV304 cell line was not detected.Histamine administration resulted in a significant expression of TF in ECV304 cell line,with strongest effect after 1 h co-incubation at concentration of 1?10-5 mol/L histamine(about 4.8-fold higher expression of TF compared with that of 1?10-9 mol/L histamine).Expression level of TF was detected after stimulated with oxHDL in dose-and time-dependent manners.The highest expression of TF mRNA was found at 20 mg/L oxHDL and 6 h co-incubation,with 1.8-fold and 5.3-fold increase in TF expression,respectively,compared with that at 10 mg/L oxHDL and 2 h co-incubation.20 mg/L oxHDL also caused an apparent augmentation of TF protein expression,about 1.5-fold higher compared with that stimulated by 40 mg/L oxHDL.HDL co-incubation did not cause a detectable expression of TF protein.The mRNA levels of TF in ECV304 cell line induced by oxHDL were decreased by 95.0%,81.0%,87.0%,respectively(all P