Serine-threonine protein kinase activation may be an effective target for reducing neuronal apoptosis after spinal cord injury

The signaling mechanisms underlying ischemia-induced nerve cell apoptosis are poorly understood. We investigated the effects of apoptosis-related signal transduction pathways following ischemic spinal cord injury, including extracellular signal-regulated kinase（ERK）, serine-threonine protein kinase（Akt） and c-Jun N-terminal kinase（JNK） signaling pathways. We established a rat model of acute spinal cord injury by inserting a catheter balloon in the left subclavian artery for 25 minutes. Rat models exhibited notable hindlimb dysfunction. Apoptotic cells were abundant in the anterior horn and central canal of the spinal cord. The number of apoptotic neurons was highest 48 hours post injury. The expression of phosphorylated Akt（pAkt） and phosphorylated ERK（p-ERK） increased immediately after reperfusion, peaked at 4 hours（p-Akt） or 2 hours（p-ERK）, decreased at 12 hours, and then increased at 24 hours. Phosphorylated JNK expression reduced after reperfusion, increased at 12 hours to near normal levels, and then showed a downward trend at 24 hours. Pearson linear correlation analysis also demonstrated that the number of apoptotic cells negatively correlated with p-Akt expression. These findings suggest that activation of Akt may be a key contributing factor in the delay of neuronal apoptosis after spinal cord ischemia, particularly at the stage of reperfusion, and thus may be a target for neuronal protection and reduction of neuronal apoptosis after spinal cord injury.

MicroRNA-760 acts as a tumor suppressor in gastric cancer development via inhibiting G-protein-coupled receptor kinase interacting protein-1 transcription

BACKGROUND Gastric cancer(GC)has become a serious threat to people's health.Accumulative evidence reveals that dysregulation of numerous microRNAs(miRNAs)has been found during malignant formation.So far,the role of microRNA-760(miR-760)in the development of GC is largely unknown.AIM To measure the expression level of miR-760 in GC and investigate its role in gastric tumorigenesis.METHODS Real-time quantitative polymerase chain reaction and Western blot analysis were used to measure the expression of miR-760 and G-protein-coupled receptor kinase interacting protein-1(GIT1).Cell growth was detected by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide(MTT)and cell colony formation assays.Apoptosis was assessed by flow cytometric analysis.The relationship between miR-760 and GIT1 was verified by luciferase reporter assay.RESULTS The results showed that the expression of miR-760 was decreased in GC and associated with poor clinical outcomes in GC patients.Furthermore,miR-760 restrained cell proliferation and cell colony formation and induced apoptosis in GC cells.In addition,miR-760 directly targeted GIT1 and negatively regulated its expression in GC.GIT1 was upregulated in GC and predicted a worse prognosis in GC patients.We also found that upregulation of GIT1 weakened the inhibitory CONCLUSION In conclusion,miR-760 targets GIT1 to inhibit cell growth and promote apoptosis in GC cells.Our data demonstrate that miR-760 may be a potential target for the treatment of GC.

All-trans Retinoic Acid Diminishes Collagen Production in a Hepatic Stellate Cell Line via Suppression of Active Protein-1 and c-Jun N-terminal Kinase Signal

Following acute and chronic liver injury,hepatic stellate cells (HSCs) become activated to undergo a phenotypic transformation into myofibroblast-like cells and lose their retinol content,but the mechanisms of retinoid loss and its potential roles in HSCs activation and liver fibrosis are not understood.The influence of retinoids on HSCs and hepatic fibrosis remains controversial.The purpose of this study was to evaluate the effects of all-trans retinoid acid (ATRA) on cell proliferation,mRNA expression of collagen genes [procollagen α1 (Ⅰ),procollagen α1 (Ⅲ)],profibrogenic genes (TGF-β 1,CTGF,MMP-2,TIMP-1,TIMP-2,PAI-1),fibrolytic genes (MMP-3,MMP-13) and the upstream element (JNK and AP-1) in the rat hepatic stellate cell line (CFSC-2G).Cell proliferation was evaluated by measuring BrdU incorporation.The mRNA expression levels of collagen genes [procollagen α1 (Ⅰ),procollagen α1 (Ⅲ)],profibrogenic genes (TGF-β 1,CTGF,MMP-2,TIMP-1,TIMP-2,PAI-1),and fibrolytic genes (MMP-3,MMP-13) were quantitatively detected by using real-time PCR.The mRNA expression of JNK and AP-1 was quantified by RT-PCR.The results showed that ATRA inhibited HSCs proliferation and diminished the mRNA expression of collagen genes [procollagen α1 (Ⅰ),procollagen α1 (Ⅲ)] and profibrogenic genes (TGF-β 1,CTGF,MMP-2,TIMP-1,TIMP-2,PAI-1),and significantly stimulated the mRNA expression of MMP-3 and MMP-13 in HSCs by suppressing the mRNA expression of JNK and AP-1.These findings suggested that ATRA could inhibit proliferation and collagen production of HSCs via the suppression of active protein-1 and c-Jun N-terminal kinase signal,then decrease the mRNAs expression of profibrogenic genes (TGF-β 1,CTGF,MMP-2,TIMP-1,TIMP-2,PAI-1),and significantly induce the mRNA expression of MMP-3 and MMP-13.

Role of Activator Protein-1 in the Transcription of Interleukin-5 Gene Regulated by Protein Kinase C Signal in Asthmatic Human TLymphocytes

Summary: In order to explore the role of activator protein-1 (AP-1) in the transcription of interleukin-5 (IL-5) gene regulated by protein kinase C (PKC) signal in peripheral blood T lymphocytes from asthmatic patient, T lymphocytes were isolated and purified from peripheral blood of each asthmatic patient. The T lymphocytes were randomly divided into 4 groups: group A (blank control), group B (treated with PKC agonist phorbol 12-myristate 13-acetate (PMA)), Group C (treated with PMA and AP-1 cis-element decoy oligodeoxynucleotides (decoy ODNs)), and group D (treated with PMA and AP-1 mutant decoy ODNs). The ODNs were transfected into the T cells of group C and D by cation liposome respectively. Reverse transcription-polymerase chain reaction (RT-PCR) was employed to assess IL-5 mRNA expression, and electrophoretic mobility shift assays (EMSA) for the activation of AP-1. The results showed that the activation of AP-1 (88 003.58±1 626.57) and the expression of IL-5 mRNA (0.8300±0.0294) in T lymphocytes stimulated with PMA were significantly higher than these in blank control (20 888.47±1103.56 and 0.3050±0.0208, respectively, P< 0.01), while the indexes (23 219.83±1 024.86 and 0.3425±0.0171 respectively) of T lymphocytes stimulated with PMA and AP-1 decoy ODNs were significantly inhibited, as compared with group B (P< 0.01). The indexes (87 107.41±1 342.92 and 0.8225±0.0222, respectively) in T lymphocytes stimulated with PMA and AP-1 mutant decoy ODNs did not exhibit significant changes, as compared with group B (P>0.05). The significant positive correlation was found between the activation of AP-1 and the expression of IL-5 mRNA (P< 0.01). It was concluded that AP-1 might participate in the signal transduction of PKC-triggered transcription of IL-5 gene in asthmatic T lymphocytes. This suggests the activation of PKC/AP-1 signal transduction cascade of T lymphocytes may play an important role in the pathogenesis of asthma.

Rho kinase:A new target for treatment of cerebral ischemia/reperfusion injury

Rho kinase inhibitor fasudil hydrochloride has been shown to reduce cerebral vasospasm, to inhibit inflammation and apoptosis and to promote the recovery of neurological function. However, the effect of fasudil hydrochloride on claudin-5 protein expression has not been reported after cerebral ischemia/reperfusion. Therefore, this study sought to explore the effects of fasudil hydrochloride on blood-brain barrier permeability, growth-associated protein-43 and claudin-5 protein expression, and to further understand the neuroprotective effect of fasudil hydrochloride. A focal cerebral ischemia/reperfusion model was established using the intraluminal suture technique. Fasudil hydrochloride （15 mg/kg） was intraperitoneally injected once a day. Neurological deficit was evaluated using Longa＇s method. Changes in permeability of blood-brain barrier were measured using Evans blue. Changes in RhoA, growth-associated protein-43 and claudin-5 protein expression were detected using immunohistochemistry and western blotting. Results revealed that fasudil hydrochloride noticeably contributed to the recovery of neurological function, improved the function of blood-brain barrier, inhibited RhoA protein expression, and upregulated growth-associated protein-43 and claudin-5 protein expression following cerebral ischemia/reperfusion. Results indicated that Rho kinase exhibits a certain effect on neurovascular damage following cerebral ischemia/reperfusion. Intervention targeted Rho kinase might be a new therapeutic target in the treatment of cerebral ischemia/reperfusion.

电项针对全脑缺血VD模型大鼠PI3K/AKT/GSK-3β信号通路的影响

目的研究电项针对全脑缺血血管性痴呆(vascular dementia,VD)模型大鼠磷脂酰肌醇-3-激酶/丝氨酸-苏氨酸蛋白激酶/糖原合成酶激酶-3β(Phosphatidylinositol-3 kinase/serine-threonine kinase/glycogen synthase kinase-3β,P13K/AKT/GSK-3β)信号通路的影响。方法采用四血管阻断方法制备VD模型大鼠,电项针组取双侧风池穴、供血穴,电针30 min/次,1次/d,治疗14d。采用Y迷宫评价大鼠学习记忆能力;荧光定量PCR(RT-PCR)、Western blot法检测大鼠海马组织中磷酸化蛋白激酶B(phosphorylatedproteinkinaseB,p-AKT)、磷酸化糖原合成酶激酶-3β(Phosphorylated GSK-3β,P-GSK-3β)mRNA和p-AKT、p-GSK-3β蛋白的表达。结果与模型组比较,电项针组可显著提高VD大鼠Y迷宫学习与记忆正确次数(P<0.01)。与模型组比较,电项针组大鼠海马组织中p-AKT、p-GSK-3βmRNA和p-AKT、p-GSK-3β蛋白表达均有不同程度的升高(P<0.01)。结论电项针能够改善VD模型大鼠学习记忆能力,具体机制可能是激活PI3K/AKT/GSK-3β信号通路,发挥抗凋亡作用,起到对缺血海马神经元的保护作用。

曲古菌素A对血管平滑肌细胞p27kip1表达的调控机制研究

目的探讨组蛋白去乙酰化酶抑制剂曲古菌素A(Trichostatin A,TSA)对血管平滑肌细胞(VSMC)的p27kip1表达的影响和调控机制。方法半定量逆转录聚合酶链反应(RT-PCR)检测p27kip1的mRNA水平,蛋白印迹测定p27kip1和S-phase kinase-associated protein-2(skp2)蛋白表达,荧光分光光度法测定20S蛋白酶体活性。结果100 ng/ml TSA不影响VSMC中p27kip1的mRNA水平。100 ng/mlTSA显著抑制血清诱导的p27kip1蛋白下调,并延长p27kip1蛋白的半衰期。100 ng/ mlTSA抑制血清诱导的skp2表达上调,且skp2表达与相应时点p27kip1蛋白呈负相关。100 ng/ml TSA对20S蛋白酶体活性物影响。结论TSA对VSMC的p27kip1表达调控不是在转录水平上,而是通过翻译后机制抑制血清诱导VSMC的p27kip1蛋白降解,其机制可能与TSA抑制泛素连接酶亚单位skp2表达有关。

Advanced oxidation protein products induce monocyte chemoattractant protein-1 expression via p38 mitogen-activated protein kinase activation in rat vascular smooth muscle cells

Background Advanced oxidation protein products （AOPPs） are new uremic toxins reported by Witko-Sarsat in 1996, which are associated with the pathogenesis of atherosclerosis. However, the mechanisms by which AOPPs enhance atherosclerosis have not been fully understood. Monocyte chemoattractant protein-1 （MCP-1） is a chemokine which stimulates migration of monocytes and plays a critical role in the development of atherosclerosis. In this study, we investigated the effect of AOPPs on MCP-1 expression in cultured vascular smooth muscle cells （VSMCs）.

RIP3/MLKL-mediated neuronal necroptosis induced by methamphetamine at 39℃

Methamphetamine is one of the most prevalent drugs abused in the world.Methamphetamine abusers usually present with hyperpyrexia (39℃),hallucination and other psychiatric symptoms.However,the detailed mechanism underlying its neurotoxic action remains elusive.This study investigated the effects of methamphetamine + 39℃ on primary cortical neurons from the cortex of embryonic Sprague-Dawley rats.Primary cortex neurons were exposed to 1 mM methamphetamine + 39℃.Propidium iodide staining and lactate dehydrogenase release detection showed that methamphetamine + 39℃ triggered obvious necrosis-like death in cultured primary cortical neurons,which could be partially inhibited by receptor-interacting protein-1 (RIP1) inhibitor Necrostatin-1 partially.Western blot assay results showed that there were increases in the expressions of receptor-interacting protein-3 (RIP3) and mixed lineage kinase domain-like protein (MLKL) in the primary cortical neurons treated with 1 mM methamphetamine + 39℃ for 3 hours.After pre-treatment with RIP3 inhibitor GSK’872,propidium iodide staining and lactate dehydrogenase release detection showed that neuronal necrosis rate was significantly decreased;RIP3 and MLKL protein expression significantly decreased.Immunohistochemistry staining results also showed that the expressions of RIP3 and MLKL were up-regulated in brain specimens from humans who had died of methamphetamine abuse.Taken together,the above results suggest that methamphetamine + 39℃ can induce RIP3/MLKL regulated necroptosis,thereby resulting in neurotoxicity.The study protocol was approved by the Medical Ethics Committee of the Third Xiangya Hospital of Central South University,China (approval numbers: 2017-S026 and 2017-S033) on March 7,2017.

Efficacy of self-made Gengnian decoction on phosphatidylinositol 3-kinases/protein kinase B/mammalian target of rapamycin signaling pathway in perimenopausal rats

OBJECTIVE:To investigate the efficacy of self-made Gengnian decoction on expressions of phosphatidylinositol 3-kinase(PI3 K),protein kinase B(Akt)and mammalian target of rapamycin(m TOR)in ovarian tissues of perimenopausal rats.They were identified with symptom pattern of kidney-Yang deficiency in terms of Traditional Chinese Medicine.METHODS:Female Sprague-Dawley rats aged10-12 months were selected.Estrous cycle was observed by vaginal smears of keratinocytes to screen the perimenopausal model rats.The chosen rats were randomly divided into five groups,including perimenopausal model of kidney-Yang deficiency group(24 rats),self-made Gengnian decoction of high-dose group(24 rats),self-made Gengnian decoction of middle-dose group(24 rats),self-made Gengnian decoction of low dose group(24 rats)and tibolone control group(24 rats).In addition,rats aged 4-6 months were selected as young control group.The perimenopausal model rats of kidney-Yang deficiency were prepared by alternative intramuscular injection of hydrocortisone 5 mg·kg^-1·d^-1The successfully prepared models in self-made Gengnian decoction of high-dose,middle-dose and low-dose groups and tibolone control group were given self-made Gengnian decoction 26.4,13.2 and 6.6 mg·kg^-1·d^-1,and tibolone tablets solvent 0.22 mg·kg^-1·d^-1,respectively,through intragastric administration.Models group and young control group were given the same dose of normal saline,1 time a day for 15 consecutive days.24 h after the last administration,blood and ovarian tissues were collected after anesthesia with 20%ethyl carbamate.The follicles of different levels in ovarian tissue were observed and counted by histopathological hematoxylin-eosin staining.Enzyme linked immunosorbent assay was applied to test insulin-like growth factor-1(IGF-1)level in the serum of experimental rats.The expression levels of PI3 K,phosphorylated-Akt(p-Akt)and phosphorylated-m TOR(p-m TOR)m RNA in ovarian tissue were detected by quantitative real-time polymerase chain reaction.RESULTS:The total follicle counts of perimenopausal model rats with kidney-Yang deficiency were significantly reduced,and the number of follicles(mainly increased in preantral follicles and antral follicles)in perimenopausal model rats with kidney-Yang deficiency was significantly increased after intervention of high and middle doses of Gengnian decoction and tibolone(P<0.05).Compared with normal rats in young control group,the levels of IGF-1 in serum of perimenopausal rats with kidney-Yang deficiency were significantly decreased(P<0.01),and those intervened by high dose of Gengnian decoction and tibolone were significantly up-regulated.The relative expression levels of PI3 K,p-Akt,p-m TOR m RNA in ovarian tissues of perimenopausal rats with kidney-Yang deficiency were significantly lower than those of young rats(P<0.01),and those intervened by high dose of Gengnian decoction and tibolone were significantly up-regulated(P<0.05).CONCLUSION:Self-made Gengnian decoction can increase the levels of IGF-1,PI3 K,Akt and m TOR m RNA expression in serum.

L-4F Inhibits Oxidized Low-density Lipoprotein-induced Inflammatory Adipokine Secretion via Cyclic AMP/Protein Kinase A-CCAAT/Enhancer Binding Protein β Signaling Pathway in 3T3-L1 Adipocytes

Background： Adipocytes behave like a rich source of pro-inflammatory cytokines including monocyte chemoattractant protein- 1 （MCP- 1）. Oxidized low-density lipoprotein （oxLDL） participates in the local chronic inflammatory response, and high-density lipoprotein could counterbalance the proinftammatory function of αLDL, but the underlying mechanism is not completely understood. This study aimed to evaluate the effect of apolipoprotein A-I mimetic peptide L-4F on the secretion and expression of MCP-1 in fully differentiated 3T3-L 1 adipocytes induced by oxLDL and to elucidate the possible mechanisms. Methods： Fully differentiated 3T3-L 1 adipocytes were incubated in the medium containing various concentration of L-4F （0-50 gg/ml） with oxLDL （50 Lag/ml） stimulated, with/without protein kinase A （PKA） inhibitor H-89 （10 gmol/L） preincubated. The concentrations of MCP- 1 in the supematant, the mRNA expression of MCP- 1, the levels of CCAAT/enhancer binding protein α （C/EBPα）, and CCAAT/ enhancer binding protein 13 （C/EBPβ） were evaluated. The monocyte chemotaxis assay was performed by micropore filter method using a modified Boyden chamber. Results： OxLDL stimulation induced a significant increase ofMCP-1 expression and secretion in 3T3-L 1 adipocytes, which were inhibited by L-4F preincubation in a dose-dependent manner. PKA inhibitor H-89 markedly reduced the oxLDL-induced MCP-1 expression, but no further decrease was observed when H-89 was used in combination with L-4F （50 μg/ml） （P 〉 0.05）. OxLDL stimulation showed no significant effect on C/EBPa protein level but increased C/EBPβ protein level in a time-dependent manner. H-89 and L-4F both attenuated C/EBPI3 protein level in oxLDL-induced 3T3-L1 adipocytes. Conclusions： OxLDL induces C/EBPI3 protein synthesis in a time-dependent manner and enhances MCP-1 secretion and expression in 3T3-L 1 adipocytes. L-4F dose-dependently counterbalances the pro-inflammatory effect of oxLDL, and cyclic AMP/PKA-C/EBP-β signaling pathway may participate in it.

Inflammation-mediated age-dependent effects of casein kinase 2-interacting protein-1 on osteogenesis in mesenchymal stem cells

Background:The casein kinase 2-interacting protein-1(CKIP-1)is important in the development of osteoblasts and cardiomyocytes.However,the effects of CKIP-1 on osteoblast precursor mesenchymal stem cells(MSCs)remain unclear.This study aimed to determine whether CKIP-1 affects osteogenic differentiation in MSCs and explore the relationship of CKIP-1 and inflammation.Methods:Bone marrow MSCs of CKIP-1 wild type(WT)and knockout(KO)mice were cultivated in vitro.Cell phenotype was analyzed by flow cytometry,colony formation was detected to study the proliferative ability.Osteogenic and adipogenic induction were performed.The osteogenic ability was explored by alizarin red staining,alkaline phosphatase(ALP)staining and ALP activity detection.Quantitative real-time polymerase chain reaction(qRT-PCR)was carried out to determine the mRNA expression levels of osteoblast marker genes.The adipogenic ability was detected by oil red O staining.Content of the bone was analyzed to observe the differences of bone imaging parameters including trabecular bone volume/tissue volume(BV/TV),bone surface area fraction/trabecular BV,trabecular number(Tb.N),and trabecular spacing(Tb.sp).Interleukin(IL)-1b was injected on WT mice of 2 months old and 18 months old,respectively.Difference in CKIP-1 expression was detected by RT-PCR and western blot.The relationship between CKIP-1 and inflammation was explored by RT-PCR and western blot.Results:ALP assays,alizarin red staining,and qRT-PCR showed that MSCs derived from CKIP-1 KO mice exhibited a stronger capability for osteogenesis.Micro-computed tomography detection showed that among 18-month-old mice,CKIP-1 KO mice presented significantly higher bone mass compared withWTmice(P=0.02).No significant difference was observed in 2-month-old mice.In vivo data showed that expression of CKIP-1 was higher in the bone marrow of aging mice than in young mice(4.3-fold increase at themRNA level,P=0.04).Finally,the expression levels of CKIP-1 in bone marrow(3.2-fold increase at themRNA level,P=0.03)and cultured MSCs were up-regulated on chronic inflammatory stimulation by IL-1b.Conclusions:CKIP-1 is responsible for negative regulation of MSC osteogenesis with age-dependent effects.Increasing levels of inflammation with aging may be the primary factor responsible for higher expression levels of CKIP-1 but may not necessarily affect MSC aging.

Growth Hormone Prevents the Memory Deficit Caused by Oxidative Stress in Early Neurodegenerative Stage in Rats

Oxidative stress has been involved in neurodegenerative diseases. The growth hormone (GH) counteracts the levels of reactive oxygen species. Previously, we showed that the prolonged exposure to ozone causes oxidative stress in the hippocampus and memory deficits. In this work, we analyzed the effects of the growth hormone on the memory deficit generated by ozone exposure, growth hormone effects on the Insulin-like growth factor I (IGF-I), and the serinethreonine protein kinase (Akt) activation in the dentate gyrus. Our results show that GH prevents memory deficits in early stages of the neurodegenerative process.

Active compounds of Caodoukou(Semen Alpinia Katsumadai)inhibit the migration,invasion and metastasis of human pancreatic cancer cells by targeting phosphoinosmde-3-kinase/protein kinase B/mammalian target of rapamycin pathway

OBJECTIVE:To detect the effects of active compounds of Caodoukou(Semen Alpinia Katsumadai)(ACAK)on the proliferation,migration and invasion of pancreatic cancer,and explain the possible molecular mechanism of ACAK interacting with these processes.Methods:Cell counting kit-8 method,cell scratch repair experiment,Transwell migration and invasion experiment,immunohistochemistry,western blot assay and real-time polymerase chain reaction experiment were used to evaluate the effect of ACAK on the proliferation,migration and invasion of pancreatic cancer cells.The levels of active molecules involved in the phosphoinosmde-3-kinase(PI3K)/Akt/the mammalian target of rapamycin(m TOR)signal transduction were detected by Western blot assay.In addition,the function of ACAK in vivo was evaluated by xenotransplantation tumor model in nude mice.Results:The inhibitory effect of ACAK on the proliferation of pancreatic cancer cells showed certain time-dose dependence.The results of scratch repair test,Transwell test,Western blotting and real time polymerase chain reaction assay showed that ACAK could inhibit the migration and invasion of pancreatic cancer cells in vitro.In addition,the regulatory effect of ACAK on epithelialmesenchymal transition(EMT)is partly attributed to PI3K/Akt/mT OR signaling pathway.The experimental results in vivo showed that ACAK regulated the development of pancreatic cancer.Conclusions:ACAK can partly inhibit the activity of EMT and matrix metallopeptidases by down-regulating the downstream proteins of PI3K/Akt/mTOR signal pathway,thus inhibiting the ability of migration and invasion of pancreatic cancer.

Electroacupuncture Pretreatment at Neiguan (PC 6) attenuates autophagy in rats with myocardial ischemia reperfusion through the phosphatidylinositol 3-kinase-Akt-mammalian target of rapamycin pathway

OBJECTIVE: To investigate the protective efficacy of electroacupuncture(EA) pretreatment at Neiguan(PC6) on myocardial ischemia-reperfusion(I/R) in rats.METHODS: Fifty rats were randomly divided into five groups(n = 10): sham operation group, model group(underwent in vivo myocardial I/R), EA pretreatment group [EA at Neiguan(PC 6) 1 week before I/R], wortmannin group(1 week before I/R, the PI3K inhibitor, wortmannin, was injected), EA pretreatment + wortmannin group(both pretreatments were performed simultaneously). After establishing the I/R model, 2,3,5-triphenyltetrazolium chloride(TTC) staining was used to analyze the weight and area of the myocardial infarction tissue.The biosignal and pressure test system was used to determine the left ventricular systolic mean pressure(LVSP), left ventricular end-diastolic pressure(LVEDP), fractional shortening(FS), and ejection fraction(EF). Ultraviolet spectrophotometry was used to determine the expression of creatine kinase(CK)-MB, inducible nitric oxide synthase(i NOS), and total antioxidant capacity(T-AOC) in the serum. The expression of autophagy-related protein 13(ATG13), mammalian target of rapamycin(m TOR), and phosphatidylinositol 3-kinase(PI3K) in cardiac muscle cells was determined by immunofluorescence. Hematoxylin and eosin staining was used to observe autophagy-related pathological changes in rat cardiomyocytes, and ultrastructural changes of cardiomyocytes were examined by transmission electron microscopy.RESULTS: In this study, the infarction size and tissue weight of the EA pretreatment group were decreased compared with the model group(P <0.0001). Furthermore, compared with the model group, the LVEDP values of the EA pretreatment group were significantly reduced(P = 0.0091), and the LVSP, FS, and EF values were slightly increased (P = 0.0007, 0.0020, 0.0031). EA pretreatment also significantly decreased the expression of CK-MB and i NOS, while it increased the expression of T-AOC in the serum of rats with I/R injury(P <0.0001). Furthermore, EA pretreatment slightly widened the myocardial fiber space, reduced necrosis and myocardial cell swelling and maintained the nucleus and mitochondria structure intact.CONCLUSION: EA pretreatment promoted autophagy flux and alleviated myocardial I/R injury through the PI3K-Akt-m TOR pathway.

Metformin inhibits nuclear factor-κB activation and inflammatory cytokines expression induced by high glucose via adenosine monophosphate-activated protein kinase activation in rat glomerular mesangial cells in vitro

Background The renoprotective mechanisms of adenosine monophosphate （AMP）-activated protein kinase （AMPK） agonist-metformin have not been stated clearly.We hypothesized that metformin may ameliorate inflammation via AMPK interaction with critical inflammatory cytokines The aim of this study was to observe the effects of metformin on expression of nuclear factor-κB （NF-κB）,monocyte chemoattractant protein-1 （MCP-1）,intercellular adhesion molecule-1 （ICAM-1） and transforming growth factor-beta 1 （TGF-β1） induced by high glucose （HG） in cultured rat glomerular mesangial cells （MCs）.Methods MCs were cultured in the medium with normal concentration glucose （group NG,5.6 mmol/L）,high concentration glucose （group HG,25 mmol/L） and different concentrations of metformin （group M1,M2,M3）.After 48-hour exposure,the supernatants and MCs were collected.The expression of NF-κB,MCP-1,ICAM-1,and TGF-β1 mRNA was analyzed by real time polymerase chain reaction.Westem blotting was used to detect the expression of AMPK,phospho-Thr-172 AMPK （p-AMPK）,NF-κB p65,MCP-1,ICAM-1,and TGF-β1 protein.Results After stimulated by HG,the expression of NF-κB,MCP-1,ICAM-1,TGF-β1 mRNA and protein of MCs in group HG increased significantly compared with group NG （P ＜0.05）.Both genes and protein expression of NF-κB,MCP-1,ICAM-1,TGF-β1 of MCs induced by high glucose were markedly reduced after metformin treatment in a dose-dependent manner （P ＜0.05）.The expression of p-AMPK increased with the rising of metformin concentration,presenting the opposite trend,while the level of total-AMPK protein was unchanged with exposure to HG or metformin.Conlusion Metformin can suppress the expression of NF-κB,MCP-1,ICAM-1 and TGF-β1 of glomerular MCs induced by high glucose via AMPK activation,which may partlv contribute to its reno-protection.

Effect of Shenzhu Tiaopi granule(参术调脾颗粒) on hepatic insulin resistance in diabetic Goto-Kakizakirats via liver kinase B1/adenosine 5’-monophosphate/mammalian target of rapamycin signaling pathway

OBJECTIVE: To observe the therapeutic effect of Shenzhu Tiaopi granule(参术调脾颗粒, STG) on insulin resistance(IR) in the liver of diabetic Goto-Kakizaki(GK) rat and investigate underlying mechanisms.METHODS: Ten 12-week-old male Wistar rats were assigned as normal control(NC) group, while 4012-week-old male specific-pathogen-free GK rats were randomly divided into four experimental groups, 10 diabetic rats each. Animals were fed with a normal diet. Fasting blood glucose(FBG), water intake, and body weight were recorded during6 weeks of daily single-dose treatment: STG low-dose group, 4.5 g/kg(STG-L);STG high-dose group,9 g/kg(STG-H);metformin group, 0.1 g/kg(MET);model control(MC) and NC groups, equal volume of 0.9% Na Cl solution. The serum fasting insulin(FINS), C-Peptide and IR index(HOMA-IR) were detected every 2 weeks during treatment and glucose tolerance was measured in the 3 rd day before the material was taken. After the 6-week STG treatment, Liver tissues were processed for hematoxylin-eosin staining to perform light microscopy analysis and for assessing expression and distribution of insulin receptor substrates(IRS-1) and glucose transporter(GLUT-4) by immunohistochemistry analysis. Expression levels of liver kinase B1(LKB1)/adenosine 5’-monophosphate-activated protein kinase(AMPK)/mammalian target of rapamycin(mTOR) pathway proteins, including LKB1, phospho-AMPK(p-AMPK)/AMPK, phospho-mTOR(p-mTOR)/mTOR, and ribosomal protein S6 kinase polypeptide 1(S6 K1),were detected by Western blotting.RESULTS: STG significantly reduced the FBG level and liver fat deposition in diabetic GK rats. After STG treatment completion, FINS, HOMA-IR, C-Peptide and area under blood glucose curve(AUC)were lower in STG groups than in the MC group, indicating that IR was reduced and liver fat lesions were resolved. In liver tissues, STG groups displayed significantly higher IRS-1 and GLUT-4 expression than the MC group, along with increased LKB1 and p-AMPK/AMPK expression and decreased p-mTOR/mTOR and phospho-S6 K1 expression, suggesting that STG stimulated LKB1 activation of AMPK and suppressed themTOR/S6 K1 downstream pathway.CONCLUSION: Growing GK rats developed hepatic IR, but STG treatment significantly improved hyperglycemia and IR and resolved hepatic fatty lesions.Interestingly, STG treatment stimulated the expression of IRS-1 and GLUT-4 in the liver of diabetic GK rats, indicating a potential involvement in the regulation of the LKB1/AMPK/mTOR signaling pathway.

Efficacy of Sijunzi decoction(四君子汤) on limb weakness in spleen Qi deficiency model rats through adenosine monophosphate-activated protein kinase/unc-51 like autophagy activating kinase 1 signaling

OBJECTIVE:To investigate the efficacy of Sijunzi decoction(四君子汤)on limb weakness in a rat model of spleen Qi deficiency(SQD),and to study its effect on mitophagy in skeletal muscle through adenosine monophosphate-activated protein kinase(AMPK)/unc-51 like autophagy activating kinase 1(ULK1)signaling.METHODS:SQD model rats were produced by fasting combined with forced swimming method for15 d.After model assessment,rats were randomly divided into four groups of 10[low/middle/high(L/M/H)Sijunzi decoction dose groups and a normal saline(S)group].Limb holding power(HP)and body mass(BM)were measured after 2 weeks of treatment.Following euthanasia,quadriceps femoris were dissected and myofiber and mitochondrial morphology were observed by transmission electron microscopy(TEM).Mitochondrial membrane potential(MMP),adenosine triphosphatase(ATP)and reactive oxygen species(ROS)levels were determined using colorimetric methods,and immunoblot analysis of Microtubule-associated protein light chain 3(LC3)and Sequestosome 1(p62)was performed to monitor mitophagy and AMPK/ULK1 signaling.RESULTS:Compared with control(C)group rats,in the S group,HP was reduced,the myofiber Z line was disordered,mitochondria were scattered,and numerous vacuoles and mitophagy were observed.MMP and ATP levels were reduced,ROS levels were elevated,and LC3B expression,and p-AMPKα(Thr172)/AMPKα,p-ULK1(Ser555)/ULK1,and p-Raptor(Ser792)/Raptor ratios were increased,while p62 expression and p-mT OR(Ser2448)/mT OR and p-ULK1(Ser757)/ULK1 ratios were decreased.After treatment,compared with the S group,HP was improved in M and H groups but not in the L group.Mitophagy was reduced in M,H and L groups but the Z line was disordered and vacuolization remained in the L group.ATP levels were elevated in M,H and L groups,and MMPs were elevated in M and H groups but not in the L group.ROS levels were decreased in M,H and L groups,as were LC3B expression and p-Raptor(Ser792)/Raptor ratios,while p62 expression and p-mT OR(Ser2448)/mT OR and p-ULK1(Ser757)/ULK1 ratios were increased in M and H groups but not in the L group.p-AMPKα(Thr172)/AMPKαand p-ULK1(Ser555)/ULK1 ratios were decreased in M,H and L groups.CONCLUSIONS:Sijunzi decoction improved HP,possibly by inhibiting mitophagy via suppression of AMPK/ULK1 signaling.This restored mitochondrial morphology and improved oxidative phosphorylation,which contributed to recovery of limb weakness in SQD model rats.

乙酰胆碱受体对胞壁酰二肽激活小鼠巨噬细胞NLR2/RIP2通路的调控作用

目的 评价乙酰胆碱受体对胞壁酰二肽（MDP）激活小鼠巨噬细胞Nod样受体2/受体相互作用蛋白2（NLR2/RIP2）通路的调控作用.方法 RAW264.7细胞长至对数生长期时,接种于12孔培养板（细胞密度1＆#215;106个/ml,2 ml/孔）,108个培养孔.采用随机数字表法,将其分为3组（n=36）,正常对照组（C组）常规培养;M组加入MDP,终浓度为10 μg/ml;G组同时加入MDP和α7烟碱型乙酰胆碱受体特异性激动剂GTS-21,终浓度分别为10、50 μg/ml.分别于MDP孵育1、6、24h时取12个培养孔,取细胞悬液,采用实时荧光定量PCR法检测NLR2 mRNA表达,采用Western blot印迹法检测RIP2表达,采用ELISA法检测培养液TNF-α和高迁移率族蛋白-1（HMGB1）的浓度.结果 与C组比较,M组不同时点NLR2 mRNA、RIP2、TNF-α和HMGB1的水平升高（P＜0.05）;与M组比较,G组不同时点NLR2 mRNA、RIP2、TNF-α和HMGB1的水平降低（P＜0.05）.结论 乙酰胆碱受体可抑制MDP激活小鼠巨噬细胞NLR2/RIP2通路转导.

c-Jun, at the crossroad of the signaling network

c-Jun,the most extensively studied protein of the activator protein-1(AP-1)complex,is involved in numerous cell activities,such as proliferation,apoptosis,survival,tumorigenesis and tissue morphogenesis.Earlier studies focused on the structure and function have led to the identification of c-Jun as a basic leucine zipper(bZIP)transcription factor that acts as homo-or heterodimer,binding to DNA and regulating gene transcription.Later on,it was shown that extracellular signals can induce post-translational modifications of c-Jun,resulting in altered transcriptional activity and target gene expression.More recent work has uncovered multiple layers of a complex regulatory scheme in which c-Jun is able to crosstalk,amplify and integrate different signals for tissue development and disease.One example of such scheme is the autocrine amplification loop,in which signal-induced AP-1 activates the c-Jun gene promoter,while increased c-Jun expression feedbacks to potentiate AP-1 activity.Another example of such scheme,based on recent characterization of gene knockout mice,is that c-Jun integrates signals of several developmental pathways,including EGFR-ERK,EGFR-RhoA-ROCK,and activin B-MAP3K1-JNK for embryonic eyelid closure.After more than two decades of extensive research,c-Jun remains at the center stage of a molecular network with mysterious functional properties,some of which are yet to be discovered.In this article,we will provide a brief historical overview of studies on c-Jun regulation and function,and use eyelid development as an example to illustrate the complexity of c-Jun crosstalking with signaling pathways.