1,8-桉叶油素调节自噬改善高糖诱导的内皮细胞损伤

目的探讨1,8-桉叶油素(1,8-Cineole)通过调节自噬来改善高糖(HG)诱导人主动脉内皮细胞(HAECs)损伤的保护作用。方法采用HG作用HAECs 60 h,不同剂量的1,8-Cineole进行干预,运用噻唑蓝(MTT)法检测细胞活力,乳酸脱氢酶(LDH)检测细胞毒性,Western blot法检测Beclin1、LC3-Ⅱ/Ⅰ、p62、caspase-3和caspase-9的蛋白表达,及使用自噬抑制剂氯喹(CQ)作用HAECs后,检测Beclin1、LC3-Ⅱ/Ⅰ、p62、caspase-3和caspase-9的表达情况。结果1,8-Cineole提高细胞活力,减少LDH含量,激活自噬和抑制细胞凋亡。与空白组比较,CQ组的Beclin1、LC3-Ⅱ/Ⅰ、p62、caspase-3和caspase-9表达增加,同时观察到CQ+HG+CH组与CQ+HG组比较时,以上蛋白差异均无统计学意义。结论1,8-Cineole对高糖诱导HAECs损伤具有保护作用,其作用与改善自噬流相关。     

补阳还五汤通过AMPK/mTOR/ULK1信号通路调控自噬减轻大鼠脑缺血/再灌注损伤

目的探讨补阳还五汤抗大鼠脑缺血/再灌注损伤的AMPK/mTOR/ULK1自噬信号通路机制。方法用改良线栓法建造大鼠左侧脑缺血模型,各组大鼠每24 h给药1次,共3次。再灌注72 h后观察大鼠神经损伤情况和脑梗死体积改变;尼氏染色法和TUNEL染色法观察神经细胞形态、数量以及凋亡情况;Western blot检测自噬蛋白和AMPK/mTOR/ULK1自噬信号通路相关蛋白表达情况。结果补阳还五汤改善大鼠神经功能缺陷,减少脑梗死体积和神经细胞凋亡,减轻脑组织病理损伤;抑制AMPK磷酸化活化,解除AMPK对下游mTOR和ULK1的抑制,促进二者磷酸化激活,抑制细胞自噬。AMPK激动剂Metformin提高细胞自噬水平,同时逆转了补阳还五汤抗大鼠脑缺血/再灌注损伤作用。结论补阳还五汤介导AMPK/mTOR/ULK1自噬信号通路对脑缺血/再灌注损伤大鼠发挥神经保护作用。     

The anti-tumourigenic effect of ellagic acid in SKOV-3 ovarian cancer cells entails activation of autophagy mediated by inhibiting Akt and activating AMPK

This study investigated the effect of ellagic acid (EA) on SKOV-3 cell growth and invasiveness and tested if the underlying mechanism involves modulating autophagy. Cells were treated with EA in the presence or absence of chloroquine (CQ), an autophagy inhibitor, compound C (CC), an AMPK inhibitor, or an insulin-like growth factor-1 (IGF-1), a PI3K/Akt activator. EA, at an IC₅₀ of 36.6 µmol/L, inhibited cell proliferation, migration, and invasion and induced cell apoptosis in SKOV-3 cells. These events were prevented by CQ. Also, EA increased levels of Beclin-1, ATG-5, LC3I/II, Bax, cleaved caspase-3/8 and reduced those of p62 and Bcl-2 in these cancer cells. Mechanistically, EA decreased levels of p-S6K1 (Thr³⁸⁹) and 4EBP-1 (Thr^37/46), two downstream targets of mTORC1, and p-Akt (Thr³⁰⁸) but increased levels of AMPK (Thr¹⁷²) and p-raptor (Ser⁷⁹²), a natural inhibitor of mTORC1. CC or IGF-1 alone partially prevented the effect of EA on cell survival, cell invasions, and levels of LDH, Beclin-1, and cleaved caspase-3. In conclusion, EA can inhibit SKOV-3 growth, migration, and invasion by activating cytotoxic autophagy mediated by inhibition of mTORC1 and Akt and activation of AMPK.     

基于AMPK/ULK1介导的自噬探讨牡荆素对鼻咽癌CNE-2细胞裸鼠移植瘤生长抑制作用及其机制

目的 探究牡荆素对鼻咽癌CNE-2细胞裸鼠移植瘤生长的抑制作用及其可能的调控机制。方法 将BALB/c裸鼠通过左侧前肢腋窝下接种CNE-2细胞构建鼻咽癌裸鼠成瘤模型,待模型构建成功后随机分为模型组、牡荆素组（5、10 mg/kg）、腺苷酸活化蛋白激酶（AMPK）激动剂组（AICAR,200 mg/kg）、牡荆素+AMPK抑制剂组（Compound C,20 mg/kg）,每组各10只。牡荆素组分别按照相应剂量ig;AICAR组ip 200 mg/kg AICAR;牡荆素+Compound C组采取ig 10 mg/kg牡荆素的同时ip 20 mg/kg Compound C,以上各组连续给药21 d。给药结束后测定裸鼠移植瘤体积和质量;苏木素–伊红（HE）染色观察移植瘤组织病理学改变;TUNEL染色检测肿瘤组织细胞凋亡情况;免疫组织化学检测肿瘤组织微管相关蛋白轻链3(LC3)-II、泛素结合蛋白（p62）蛋白表达;免疫荧光检测肿瘤组织LC3-II和半胱氨酸天冬氨酸蛋白酶-3(Caspase-3)表达;Western blotting检测肿瘤组织Bcl-2相关X蛋白（Bax）、B淋巴细胞...     

6-Paradol alleviates Diclofenac-induced acute kidney injury via autophagy enhancement-mediated by AMPK/AKT/mTOR and NLRP3 inflammasome pathways

Diclofenac (DIC)-induced acute kidney injury (AKI) causes high morbidity and mortality. With the absence of satisfactory treatment, we investigated the protective effects of 6-Paradol (PDL) against DIC-induced AKI, with focus on renal autophagy and NLRP3 inflammasome pathways . PDL has anti-inflammatory, antioxidant and AMPK-activation properties. PDL was administered to DIC-challenged rats. Nephrotoxicity, oxidative stress, inflammatory, and autophagy markers and histopathological examinations were evaluated. Compared to DIC, PDL restored serum nephrotoxicity, renal oxidative stress and pro-inflammatory markers. PDL almost restored renal architecture, upregulated renal Nrf2 pathway via enhancing Nrf2 mRNA expression and HO-1 levels. PDL suppressed renal NF-κB mRNA expression, and NLRP3 inflammasome pathway expression. Moreover, PDL enhanced renal autophagy through upregulating LC3B, AMPK and SIRT-1, and suppressed mTOR, p-AKT mRNA expressions and phosphorylated-p62 levels. Our study confirmed that autophagy suppression mediates DIC-induced AKI via AMPK/mTOR/AKT and NLRP3-inflammasome pathways. Also, PDL’s nephroprotective effects could provide a promising therapeutic approach against DIC-induced AKI.     

Calycosin induces apoptosis in adenocarcinoma HT29 cells by inducing cytotoxic autophagy mediated by SIRT1/AMPK‐induced inhibition of Akt/mTOR

Autophagy promotes cell survival or induces apoptosis in cancer cells. While SIRT1 and AMPK induce autophagy in both normal and cancer cells, Akt and mTOR can inhibit it. Calycosin, a methoxyisoflavone, protects against several types of solid tumours including colorectal cancer. However, the mechanisms behind the antitumour effect of Calycosin remain largely unknown. This study investigates if autophagy mediates the anti‐tumourigenesis effect afforded by Calycosin and examines if this effect involves activation of SIRT1 and/or AMPK. Human colorectal (HT29) carcinoma cells were cultured under normal conditions with Calycosin (50 μmol/L) in the presence or absence of chloroquine (10 μmol/L), EX‐527 (100 nmol/L, SIRT1 inhibitor), or IGF‐1 (100 ng/mL, Akt/mTOR activator) for 48 hours. Calycosin inhibited cell growth, proliferation and invasion and increased protein levels of Beclin‐1 and LC3II, markers of autophagy. It significantly increased protein levels of cleaved caspase‐3, Bax, and SIRT1, and activity of AMPK and reduced those of Bcl‐2. These effects were parallel with concomitant reduction in protein levels p‐src, integrin‐β1 and Cyclin‐D1 and activities of Akt and mTOR. Inhibition of autophagy by CQ reversed all these effects except cell invasion. Interestingly, co‐incubating the cells with either EX‐527 or IGF‐1 completely prevented Calycosin‐induced autophagy and all other associated effects and increased cell invasion. Also, blockade of SIRT‐1 prevented the activation of AMPK, Akt, and mTOR, suggesting it to be an upstream regulator of these markers. In conclusion, Calycosin stimulates CRC cell apoptosis and inhibits their invasion by acting as SIRT1 activator which induces activation of AMPK‐induced inhibition of Akt/mTOR axis.     

Triptolide‐induced hepatotoxicity via apoptosis and autophagy in zebrafish

Previous research about the development of triptolide (TP) as a natural active compound has often focused on hepatotoxicity. Among its various mechanisms, autophagy and apoptosis are two important signaling pathways. In this study, we used zebrafish to establish a TP‐induced hepatotoxicity model, and investigated the roles of autophagy and apoptosis in the progress of liver injury. Zebrafish exposed to TP showed increased mortality and malformation because of the increased drug dose and duration of exposure. Meanwhile, we found that TP induced liver injury in a time‐ and dose‐dependent manner, which was observed as a reduction in liver area, slow yolk absorption, upregulation of transaminase and local neurosis. With the application of the high‐content imaging system (HCIS) technique in liver 3D imaging in vivo, clear imaging of the zebrafish liver was achieved. The results showed a decrease in volume and location of necrosis in the liver after TP exposure. Increased expression of inflammatory cytokines genes tumor necrosis factor (Tnf)α, Il1β and Il6 were shown, particularly Tnfα. The Fas‐Caspase8 signaling pathway was activated. The apoptosis‐related gene Bcl‐2 was increased, and Bax, Caspase9 and Caspase3 were increased. However, autophagy related genes Beclin1, Atg5, Atg3 and Lc3 were increased more significantly, and the changes of Beclin1 and Atg5 were the most severe. This study successfully established a TP‐induced zebrafish hepatotoxicity model and applied the HCIS technique in a zebrafish hepatotoxicity study. The result indicated Fas might be the main target of TP‐induced hepatotoxicity. Autophagy played a more important role than apoptosis and was characterized by the overexpression of Beclin1 and Atg5.     

灯盏花素通过激活线粒体自噬途径减轻糖尿病大鼠心肌缺血再灌注损伤

目的 探讨灯盏花素对糖尿病大鼠心肌缺血再灌注损伤(MIRI)及线粒体自噬途径的影响.方法 采用高糖高脂饮食联合链脲佐菌素制备糖尿病模型,糖尿病模型成功后再制备MIRI模型,具体分组为对照组(不做任何处理)、模型组(糖尿病+MIRI)、假手术组(糖尿病),均ip等体积生理盐水;灯盏花素低、高剂量组(糖尿病+MIRI),分...     

3‐Methyladenine alleviates excessive iodine‐induced cognitive impairment via suppression of autophagy in rat hippocampus

Drinking water with high levels of iodine has been identified as the key contributor to iodine excess, but the mechanisms of neurotoxicity induced by excessive iodine remain elusive. The present study aimed to explore the role of autophagy in the neurotoxic effect induced by excessive iodine in vivo. The Morris water maze test results demonstrated that excessive iodine impaired the learning and memory capabilities of rats, which were associated with marked body weight and brain weight abnormalities. In addition, iodine treatment increased malondialdehyde accumulation, decreased superoxide dismutase activity and glutathione (GSH) level, and enhanced levels of autophagy markers in the hippocampus. Notably, inhibition of autophagy with 3‐methyladenine (3‐MA) could significantly alleviate excessive iodine‐induced cognitive impairment. These data imply that autophagy is involved in the cognitive impairment elicited by excessive iodine as a pathway of cell death, and inhibition of autophagy via 3‐MA may significantly alleviate the above damage.     

Silymarin attenuates paraquat‐induced lung injury via Nrf2‐mediated pathway in vivo and in vitro

The present study aims to investigate the impacts and mechanisms of silymarin on paraquat (PQ)‐induced lung injury in vivo and in vitro. In in vivo experiments, a total of 32 male Sprague‐Dawley (SD) rats were randomly divided into four groups. The rats were killed on day 3. Histopathological changes in lung tissue were examined using HE and Masson's trichrome staining. Biomarkers of neutrophil activation, pulmonary oedema, pulmonary fibrosis, lung permeability and oxidative stress were detected. Several proinflammatory mediators and antioxidant related proteins were measured. In in vitro experiments, A549 cells were transfected with Nrf2 special siRNA to investigate the roles of Nrf2. The results show that silymarin administration abated PQ‐induced lung histopathologic changes, decreased inflammatory cell infiltration and lung wet weight/dry weight (W/D) ratio, suppressed myeloperoxidase (MPO) activity and nitric oxide (NO)/inducible nitric oxide synthases (iNOS) expression, downregulated hydroxyproline (HYP) levels, reduced total protein concentration and proinflammatory mediator release, and improved oxidative stress (malondialdehyde, MDA; superoxide dismutase, SOD; catalase, CAT; and glutathione peroxidase, GSH‐Px) in lung tissue and serum. Meanwhile, treatment with silymarin upregulated the levels of nuclear factor‐erythroid‐2‐related factor 2 (Nrf2), heme oxygenase‐1 (HO‐1) and NAD(P)H:quinone oxidoreductase‐1(NQO1). However, the addition of Nrf2 siRNA reduced the expression of Nrf2‐mediated antioxidant protein HO‐1 and thus reversed the protective effects of silymarin against oxidative stress and inflammatory response. These results suggest that silymarin may exert protective effects against PQ‐induced lung injury. Its mechanisms were associated with the Nrf2‐mediated pathway. Therefore, silymarin may be a potential therapeutic drug for lung injury.     

Artesunate alleviates intracerebral haemorrhage secondary injury by inducing ferroptosis in M1-polarized microglia and suppressing inflammation through AMPK/mTORC1/GPX4 pathway

Intracerebral haemorrhage (ICH) is a catastrophic subtype of stroke with severe morbidity and mortality. However, little progress has been made in the subsequent secondary injury. Artesunate, a water-soluble semi-synthetic derivative of artemisinin, exhibits remarkable pharmacological effects on anti-neuroinflammation. However, the effects of artesunate on ICH remain unknown. In the present study, haemoglobin (Hb) treatment in BV2 cell and collagenase type IV intracerebroventricular injection in Sprague–Dawley rats were used to establish in vitro and in vivo ICH models, respectively. For in vivo, the neurological scores, haematoma volume, brain oedema, inflammatory factors and iron deposition were evaluated. Besides, lipopolysaccharide (LPS) was used in in vitro to polarize BV2 cell to M1 phenotype. Cell viability, cellular reactive oxygen species (ROS), Fe²⁺ concentration, and lipid peroxidation levels, ferroptosis-associated proteins and mRNA, morphological of mitochondria were measured in vitro. Additionally, the AMP-activated protein kinase (AMPK)/mammalian/mechanistic target of rapamycin (mTOR) pathway were measured by western blot and immunofluorescence staining. The present in vivo results indicated that artesunate significantly ameliorated neurological deficits, haematoma volume and brain oedema in ICH rats. Besides, artesunate suppressed the M1-microglia relative inflammatory factors and up-regulated iron deposition. For in vitro, artesunate significantly selectively decreased the viability of LPS-stimulated BV2 cell. Furthermore, ROS and lipid peroxidation levels were up-regulated. And the glutathione peroxidase 4 (GPX4) were silenced via the AMPK/mTORC1 axis. Our finding supports that artesunate ameliorates the ICH secondary injury both in vitro and in vivo by inducing ferroptosis in microglia and further inhibiting inflammation mainly through the AMPK/mTORC1/GPX4 pathway. This finding may provide a novel target for ICH treatment.     

Taurine prevents high‐fat diet‐induced‐hepatic steatosis in rats by direct inhibition of hepatic sterol regulatory element‐binding proteins and activation of AMPK

This study investigated if the protective effect of taurine against high fat diet‐induced hepatic steatosis involves modulating the hepatic activity of 5' AMP‐activated protein kinase (AMPK) and levels/activity of the sterol regulatory element‐binding proteins‐1/2 (SREBP1/2). Rats were divided into four groups (n = 12/group) as (a) STD, fed standard diet (3.85 kcal/g); (b) STD + taurine (500 mg/kg); (c) HFD, fed HFD (4.73 kcal/g); and (d) HFD + taurine. All treatments were conducted for 12 weeks. Independent of food intake or modulating glucose or insulin levels, taurine administration to STD and HFD‐fed rats significantly lowered weekly weight gain and the accumulation of the retroperitoneal, visceral and subcutaneous fats. In both groups, taurine also reduced serum and hepatic levels of triglycerides and cholesterol and reduced hepatic mRNA and protein levels of fatty acid synthase (FAS), acetyl CoA carboxylase‐1 (ACC‐1), HMG‐CoA‐reductase and HMG‐CoA synthetase. In control rats only, taurine reduced hepatic levels of mature forms of sterol regulatory element‐binding proteins (SREBP)‐1/2. In HFD‐fed rats, taurine reduced SREBP‐1/2 precursor and mature forms in the livers of HFD‐fed rats. Besides, taurine significantly increased levels of glutathione (GSH), the activity of superoxide dismutase (SOD), and the activity of AMPK and its downstream β‐oxidation genes including peroxisome proliferator‐activated receptor‐α (PPAR‐α) and carnitine palmitoyltransferase (CPT‐1) in the livers of both the control and HFD‐fed rats. In conclusion, taurine protects against HFD‐induced hepatic steatosis stimulating antioxidant levels, and concomitant stimulating hepatic β‐oxidation and suppressing lipid synthesis, mediated by activation of AMPK and suppression of SREBP‐1.     

Berberine attenuates septic cardiomyopathy by inhibiting TLR4/NF-κB signalling in rats

ContextBerberine (Ber) can increase the survival rate of septic mice and inhibit inflammation, but whether it has a protective effect on septic cardiomyopathy (SCM) is unclear.ObjectiveTo investigate whether Ber ameliorates SCM in a rat model and its potential mechanism.Materials and methodsMale SD rats were randomly divided into three groups: control (Con, n = 6) (DD H₂O, 2 mL/100 g, ig, qd × 3 d, then saline, 10 mg/kg, ip); sepsis [LPS (lipopolysaccharide), n = 18] (LPS 10 mg/kg instead of saline, ip); and berberine intervention (Ber, n = 18) (Ber, 50 mg/kg instead of DD H₂O, ig, qd × 3 d, LPS instead of saline, ip). Hemodynamics, HE staining, ELISA and western blot were performed at 6, 24, and 48 h after intraperitoneal injection of LPS to evaluate the effect of berberine in septic rats.ResultBerberine could recover myocardial injury by partially increased ± dp/dt max (1151, 445 mmHg/s) and LVEDP levels (1.49 mmHg) with LPS-induced rats, as well as an ameliorated increase of cTnT (217.53 pg/mL) in the Ber group compared with that in the LPS group (at 24 h). In addition, HE staining results showed that berberine attenuated the myocardial cell swelling induced by LPS. In contrast to the LPS group, the up-regulation of TLR4, p65 TNF-α, and IL-1β were attenuated in the Ber group.Discussion and conclusionsBerberine showed a protective effect on septic cardiomyopathy rats possibly through inhibiting the activation of TLR4/NF-κB signalling pathway. Whether it improves SCM through other mechanisms is our ongoing research.     

Quercetin simultaneously induces G0/G1‐phase arrest and caspase‐mediated crosstalk between apoptosis and autophagy in human leukemia HL‐60 cells

Quercetin is a plant‐derived bioflavonoid with high anticancer activity in various tumors. Herein, the molecular mechanisms by which quercetin exerts its anticancer effects against HL‐60 acute myeloid leukemia (AML) cells were investigated. Results showed that quercetin suppressed cell proliferation in the HL‐60 cell line in vitro and in vivo. Quercetin‐induced G ₀/G₁‐phase arrest occurred when expressions of cyclin‐dependent kinase (CDK)2/4 were inhibited and the CDK inhibitors, p16 and p21, were induced. Moreover, quercetin treatment not only activated proapoptotic signaling like poly (ADP ribose) polymerase (PARP)?1 cleavage and caspase activation but also triggered autophagy events as shown by the increased expression of light chain 3 (LC3)‐II, decreased expression of p62, and formation of acidic vesicular organelles. Interestingly, it was found that use of the autophagy inhibitor, 3‐methyladenine, significantly enhanced quercetin‐mediated apoptotic cell death as analyzed by MTS and DNA fragmentation assays. Moreover, pretreatment of HL‐60 cells with the pan‐caspase inhibitor, Z‐VAD‐fmk, dramatically reversed quercetin‐mediated apoptotic and autophagic cell death. Although apoptosis and autophagy are two independent cell death pathways, our findings indicated that quercetin can activate caspases to trigger these two pathways, and both pathways played contrary roles in quercetin‐mediated HL‐60 cell death. In conclusion, besides promoting apoptosis, quercetin also induced cytoprotective autophagy in HL‐60 cells, and inhibition of autophagy may be a novel strategy to enhance the anticancer activity of quercetin in AML.