Automated FRET quantification shows distinct subcellular ERK activation kinetics in response to graded EGFR signaling in Drosophila

Threshold responses to an activity gradient allow a single signaling pathway to yield multiple outcomes. Extracellular signal‐regulated kinase (ERK) is one such signal, which couples receptor tyrosine kinase signaling with multiple cellular responses in various developmental processes. Recent advances in the development of fluorescent biosensors for live imaging have enabled the signaling activities accompanying embryonic development to be monitored in real time. Here, we used an automated computational program to quantify the signals of a fluorescence resonance energy transfer (FRET) reporter for activated ERK, and we used this system to monitor the spatio‐temporal dynamics of ERK during neuroectoderm patterning in Drosophila embryos. We found that the cytoplasmic and nuclear ERK activity gradients show distinct kinetics in response to epidermal growth factor receptor activation. The ERK activation patterns implied that the cytoplasmic ERK activity is modulated into a threshold response in the nucleus.     

AMPK activity is required for the induction of anhydrobiosis in a tardigrade Hypsibius exemplaris,and its potential up‐regulator is PP2A

The anhydrobiotic tardigrade, Hypsibius exemplaris, was previously considered to require de novo gene expression and protein phosphatase 1 (PP1) and protein phosphatase 2A (PP2A) activity for successful anhydrobiosis. These indicate that H. exemplaris has signal transduction systems responding to desiccation stress, with the involvement of phosphorylation events. To this end, we carried out time‐series phosphoproteomics of H. exemplaris exposed to mild desiccation stress and detected 48 phosphoproteins with significant differential regulations. Among them, immediate and successive reduction of phosphorylation levels of AMP‐activated protein kinase (AMPK) was observed. The subsequent chemical genetic approach showed that AMPK was activated during the preconditioning stage for anhydrobiosis, and inhibition of its activity impaired successful anhydrobiosis. As PP2A is known to dephosphorylate AMPK in other organisms, we suggested that decreased phosphorylation levels of AMPK upon mild desiccation stress were caused by dephosphorylation by PP2A. Accordingly, phosphoproteomics of animals pre‐treated with the PP1/PP2A inhibitor cantharidic acid (CA) lacked the decrease in phosphorylation levels of AMPK. These observations suggest that AMPK activity is required for successful anhydrobiosis in H. exemplaris, and its phosphorylation state is possibly regulated by PP2A.     

Cytokine-targeted therapy for the management of solid organ transplant recipients

IntroductionThe number of solid organ transplants completed annually continues to trend upwards each year. Despite this, maintenance immunosuppression available on the market has remained relatively stagnant. Standard triple immunosuppression, composed typically of tacrolimus, mycophenolate, and steroids, lead to many side effects that limit the use of these medications. Tacrolimus, specifically, causes nephrotoxicity that can lead to renal dysfunction requiring a kidney transplant down the road. Alternative therapies for the management of immunosuppression need to be identified to try to mitigate these adverse effects.BodyCytokines are responsible for facilitating T cell differentiation and lead to the activation of inflammatory mediators that can contribute to graft damage and ultimately rejection. IL-4, IL-6, IL-12/23, and IL-15 are attractive targets for medications to try to ameliorate graft rejection. Various cytokine-targeted medications are currently available on the market for the treatment of inflammatory and autoimmune conditions such as rheumatoid arthritis, psoriatic arthritis, Crohn’s, and multiple sclerosis.ConclusionThis article reviews cytokine involvement in alloimmunity and the potential role cytokine-targeted therapy may play in prevention of allograft rejection in solid organ transplant recipients.     

Type I error probability spending for post–market drug and vaccine safety surveillance with binomial data

Type I error probability spending functions are commonly used for designing sequential analysis of binomial data in clinical trials, but it is also quickly emerging for near–continuous sequential analysis of post–market drug and vaccine safety surveillance. It is well known that, for clinical trials, when the null hypothesis is not rejected, it is still important to minimize the sample size. Unlike in post–market drug and vaccine safety surveillance, that is not important. In post–market safety surveillance, specially when the surveillance involves identification of potential signals, the meaningful statistical performance measure to be minimized is the expected sample size when the null hypothesis is rejected. The present paper shows that, instead of the convex Type I error spending shape conventionally used in clinical trials, a concave shape is more indicated for post–market drug and vaccine safety surveillance. This is shown for both, continuous and group sequential analysis.     

白芍总苷对NAFLD大鼠HMGB1，TLR4通路的干预作用

目的:探讨白芍总苷(TGP)对高脂-果糖诱导非酒精性脂肪性肝病(NAFLD)大鼠肝组织中高迁移率族蛋白1(HMGB1),Toll样变体4(TLR4)信号通路的影响及其作用机制。方法:用高脂-高果糖餐诱导NAFLD大鼠模型,除设正常组外,将模型大鼠随机分为模型组,水飞蓟宾组,二甲双胍组(200 mg·kg~(-1)·d~(-1)),TGP高、低剂量组(200,100 mg·kg~(-1)·d~(-1))。用药6周后观察各组大鼠空腹血糖(FBG),餐后2 h血糖(2 hBG),胰岛素(Fins),总胆固醇(TC),低密度脂蛋白胆固醇(LDLC),高密度脂蛋白胆固醇(HDL-C),甘油三酯(TG),游离脂肪酸(FFA),丙氨酸氨基转移酶(ALT),天门冬氨酸氨基转移酶(AST)水平,计算胰岛素抵抗指数(HOMA-IR)和肝脏指数;并以免疫蛋白印迹法(Western blot)检测肝组织中HMGB1,TLR4蛋白的表达。结果:与正常组比较,模型组转氨酶,肝脏指数,血脂,2 hBG,Fins,HOMA-IR及TLR4,HMGB1蛋白均明显升高(P0.05,P0.01);与模型组比较,TGP高、低剂量组2 hBG,Fins,HOMA-IR,LDL-C,TG,TC,FFA,ALT,AST均明显降低(P0.05,P0.01),高、低剂量TGP在拮抗胰岛素抵抗、降糖降脂,改善肝功能有较显著的作用,TGP高、低剂量组均可下调HMGB1,TLR4蛋白的表达(P0.01)。结论:在NAFLD病程进展中,HMGB1,TLR4是导致炎症的其中一条通路,TGP通过下调HMGB1,TLR4信号通路的表达而起到抑制大鼠NAFLD炎症发展的作用。     

Functional magnetic resonance imaging of human jaw movements

This study used functional magnetic resonance images (fMRI) to examine brain activity during clenching, gum chewing, and tapping tasks. It has been considered difficult to obtain sufficient fMRI data during jaw movement because the head motion associated with the jaw movements creates artifacts on the images. To avoid these artifacts, larger pixels were used, thus allowing some head motion of the subjects, and data from subjects where the heads were evaluated to have moved more than 0.5 mm were discarded. Further, all pixels obtained by fMRI were evaluated and pixels positively synchronized with the task, which were considered to show brain activity, were selected. Sufficient fMRI data was obtained from 30 experiments, 10 sets for each task. During the clenching and tapping tasks, the activated pixels were in the sensory, motor and pre-motor cortexes, and in the sensory and motor cortexes but not in the pre-motor cortex during the gum chewing task. There appears to be no significant differences between right- and left-hemispheres. It is conceivable that there are differences between voluntary jaw movements (clenching and tapping tasks) and mastication (gum chewing task) concerning the control of jaw movements.