Effects of electroacupuncture on the expression of p70 ribosomal protein S6 kinase and ribosomal protein S6 in the hippocampus of rats with vascular dementia

This study investigated the mechanism underlying electroacupuncture therapy for vascular dementia through electroacupuncture at the acupoints of Baihui （DU20）, Dazhui （DU14）, and bilateral Shenshu （BL23） in a rat model of vascular dementia produced by bilateral middle cerebral artery occlusion. Morris water maze test showed that electroacupuncture improved the learning ability of vascular dementia rats. Western blot assay revealed that the expression of p70 ribosomal protein S6 kinase and ribosomal protein S6 in vascular dementia rats was significantly increased after electroacupuncture, compared with the model group that was not treated with acupuncture. The average escape latency was also shortened after electroacupuncture, and escape strategies in the spatial probe test improved from edge and random searches, to linear and trending swim pathways. The experimental findings indicate that electroacupuncture improves learning and memory ability by up-regulating expression of p70 ribosomal protein S6 kinase and ribosomal protein S6 in the hippocampus of vascular dementia rats.

AMPK-associated signaling to bridge the gap between fuel metabolism and hepatocyte viability

The adenosine monophosphate-activated protein kinase (AMPK) and p70 ribosomal S6 kinase-1 pathway may serve as a key signaling flow that regulates energy metabolism; thus, this pathway becomes an attractive target for the treatment of liver diseases that result from metabolic derangements. In addition, AMPK emerges as a kinase that controls the redox-state and mitochondrial function, whose activity may be modulated by antioxidants. A close link exists between fuel metabolism and mitochondrial biogenesis. The relationship between fuel metabolism and cell survival strongly implies the existence of a shared signaling network, by which hepatocytes respond to challenges of external stimuli. The AMPK pathway may belong to this network. A series of drugs and therapeutic candidates enable hepatocytes to protect mitochondria from radical stress and increase cell viability, which may be associated with the activation of AMPK, liver kinase B1, and other molecules or components. Consequently, the components downstream of AMPK may contribute to stabilizing mitochondrial membrane potential for hepatocyte survival. In this review, we discuss the role of the AMPK pathway in hepatic energy metabolism and hepatocyte viability. This information may help identify ways to prevent and/or treat hepatic diseases caused by the metabolic syndrome. Moreover, clinical drugs and experimental therapeutic candidates that directly or indirectly modulate the AMPK pathway in distinct manners are discussed here with particular emphasis on their effects on fuel metabolism and mitochondrial function.

乳腺癌组织中mTOR/p70S6K信号通路表达及临床意义

目的：分析哺乳动物雷帕霉素靶蛋白/70 kDa核糖体蛋白S6激酶（mTOR/p70S6K）信号通路在乳腺癌组织中的表达水平，并初步探究其在乳腺癌发生、发展中的作用及临床意义。方法选取2013年1月至2016年1月滨州医学院附属滨州市中心医院手术切除的新鲜乳腺癌标本40例，均取相应癌旁组织40例作对照，和32例非乳腺癌乳腺组织，采用逆转录聚合酶链反应（RT-PCR）技术，免疫组织化学技术检测40例乳腺癌患者癌组织、癌旁乳腺组织及32例正常乳腺组织中mTOR及P70S6K的表达情况，分析mTOR及p70S6K mRNA的表达与相关临床参数的关系。结果 mTOR mRNA在乳腺癌组织中的表达水平（0.611±0.098）显著高于在癌旁乳腺组织（0.419±0.101）和正常乳腺组织（0.381±0.043）中的表达水平，p70S6K mRNA在乳腺癌组织中的表达水平（0.625±0.109）显著高于在癌旁乳腺组织（0.471±0.129）和正常乳腺组织（0.441±0.130）中的表达水平，差异均有统计学意义（均P〈0.05）。mTOR和p70S6K在乳腺癌组织中的表达呈正相关（γ=0.491，P=0.019）。mTOR及p70S6K mRNA在乳腺癌组织中的表达水平与病理分期、有无淋巴结转移等明显相关，而与肿瘤直径、年龄等无明显关系。结论 mTOR/p70S6K信号通路在乳腺癌组织中特异性激活，mTOR/P70S6K信号通路可能在乳腺癌的发生、发展中发挥重要作用。

Effect of Metformin-Induced Stimulation on the Expression of Insulin Receptor Substrate 1 through Negative Regulation of P70S6k

Objective:The aim is to study the effects of metformin on the expression of 70 kDa ribosomal protein S6 kinase(P70S6k),insulin receptor substrate 1(IRS-1),and IRS-1Ser307 phosphorylation in human luteinized granulosa cells.Methods:Granulosa cells in the experimental group were cultured in M199 medium containing 0.1 mmol/L metformin for 24 h and those in control group were cultured in M199 medium.The expression levels of P70S6k and IRS-1 mRNA were detected by reverse-transcriptiom polymerase chain reaction(RT-PCR)and real-time PCR.P70S6k,IRS-1,p-ser307-IRS-1,and p-thr389-P70S6k protein expression levels were detected by immunofluorescence and western blotting.Results:P70S6k mRNA level was higher and IRS-1 was significantly lower in the experimental group than those in the control group.IRS-1 and p-ser307-IRS-1 were expressed in cell plasma,and P70S6k and p-thr389-P70S6k were expressed in cell nucleus.The results of Western blot analysis indicated that the expression levels of P70S6k,p-thr389-P70S6k,IRS-1,and p-ser307-IRS-1 proteins had significant difference between the experimental group and the control group.Compared to the control group,the relative intensity illustrated that the expression levels of P70S6K and p-thr389-P70S6k significantly increased in the experimental group;however,those of IRS-1 and p-ser307-IRS-1 proteins significantly decreased.Conclusion:Metformin can inhibit the P70S6k mRNA and protein expression levels in the granulosa cells and improve insulin sensitivity by regulating IRS-1 expression through Akt/P70S6k/IRS-1-dependent pathway.

Activation of mammalian target of rapamycin contributes to pain nociception induced in rats by BmK I, a sodium channel-specific modulator

The mammalian target of rapamycin （mTOR） pathway is essential for maintenance of the sensitivity of certain adult sensory neurons. Here, we investigated whether the mTOR cascade is involved in scorpion envenomation-induced pain hypersensitivity in rats. The results showed that intraplantar injection of a neurotoxin from Buthus martensii Karsch, BmK I （10 pg）, induced the activation of mTOR, as well as its downstream molecules p70 ribosomal S6 protein kinase （p70 S6K） and eukaryotic initiation factor 4E-binding protein 1 （4E-BP1）, in lumbar 5-6 dorsal root ganglia neurons on both sides in rats. The activation peaked at 2 h and recovered 1 day after injection. Compared with the control group, the ratios of p-mTOR/p-p70 S6K/p-4E- BP1 in three types of neurons changed significantly. The cell typology of p-mTOR/p-p70 S6K/p-4E-BP1 immuno-reactive neurons also changed. Intrathecal administration of deforolimus, a specific inhibitor of mTOR, attenuated BmK I-induced pain responses （spontaneous flinching, paroxysmal pain-like behavior, and mechanical hypersensitivity）. Together, these results imply that the mTOR signaling pathway is mobilized by and contributes to experimental scorpion sting-induced pain.