Abstract:The two major degradation pathways of eukaryotic cells, autophagy- lysosome and ubiquitin- proteasome systems, have been found. The two degradation pathways were, for a long time, regarded as independent degradation pathways. However, recent evidence strongly suggest that there is crosstalk between the two degradation pathways. For example, perturbations either pathway have been reported to affect the activity of the other pathway. And inhibition of proteasome may stimulate autophagy activity. The roles of ubiquitin are also found far more than previously imagined. Ubiquitin not only has "traditional function" targeting proteins for proteasome degradation, but also is involved in ubiquitylating substrates for degradation of autophagy- lysosome system. So ubiquitin is a common tag of these main degradation pathways. These degradation systems share certain substrates and regulators, and show coordinated and, in some contexts, compensatory function. The coordinated and compensatory relationship between these degradation systems that becomes critical in many cellular processes. Therefore, abnormities in these degradation systems involves not only aberrant cellular functions but also occurrence and development of many diseases. Understanding functions and crosstalk of these major degradation pathways will provide further insights into the repertoire of these degradation pathways, help to understand diverse cellular catabolic processes and facilitate our development of related new drugs.

Abstract:Itch is an unpleasant sensory, that produces a desire to scratch. Comparable to pain, itch is a warning system against potential threats to the host. However, chronic itch is pathological feature, which has a dramatic impact on the life quality of the patient. At present, two pathways of itch have been discovered: one is histamine-dependent pathway, another is histamine-independent pathway. In these itch pathways, different transmitters and receptors play very important roles, such as histamine, cowhage and chloroquine. In many of hypothesis about the mechanism of itch formation, the selective hypothesis and the specificity hypothesis have major impacts. This review summarizes the research progress of itch signal pathways and related receptors in recent years.

Abstract:Chromatin immunoprecipitation followed by sequencing (ChIP-seq) is a burgeoning technique which combines Chromatin immunoprecipitation (ChIP) with massively parallel DNA sequencing to detect protein-DNA binding events, histone modifications, nucleosomes positioning and DNA methylation on a genome-wide scale. Motivated by the tremendous progress in next-generation sequencing (NGS) technology, ChIP-seq offers higher resolution, less noise, and broader coverage than conventional microarray based ChIP-chip．With the decreasing cost of sequencing, ChIP-seq has become an indispensable tool for studying gene regulation and epigenetic mechanisms. In this review, we describe its latest advances, with an emphasis on issues related to data analysis and its application.

Abstract:Plant hormones play important roles during plant growth and development. The latest two research papers proposed detailed molecular mechanisms on the regulation of cell elongation and photomorphogenesis by the interaction and cooperation of light signaling and two phytohormones, brassinosteroid and gibberellin, which also provide theoretical basis for improving crop yields.

Abstract:The medial geniculate body (MGB, the auditory thalamus) receives strong corticofugal modulation that includes facilitation and inhibition. Auditory stimuli evoke an onset response that in many neurons followed by a lasting post response inhibition in MGB neurons. In the present study, we investigated the post response inhibition of MGB neurons in sleeping rats. Chronically implanted electrodes were used to record the neuronal activities of the MGB, as well as, the electroencephalogram (EEG) and the electromyography (EMG) from the rats in different stages of sleep. Both ON and ON-OFF neurons in the MGB showed prolonged post-response inhibition of over 　50 ms. The post-response inhibition showed a shorter duration in rapid eye movement (REM) sleep than that in non-rapid eye movement (NREM) sleep. After the auditory sector of the thalamic reticular nucleus (TRN) was reversibly inactivated by local application of lidocaine, the post-response inhibition of MGB neurons disappeared or decreased. Based on these results, we concluded that the TRN was involved in the post response inhibition of the MGB in sleep. The TRN applied stronger inhibition to the MGB neurons during non-REM sleep than during REM sleep.

Abstract:Sp100 is a constitutive protein of nuclear domain 10 (ND10) and is ubiquitous in mammal cells. It is involved in many cellular processes such as transcriptional regulation and the cellular intrinsic immune response against viral infection. Using a yeast mating assay, we found that Sp100 can interact with HIV-1 integrase (HIV-1 IN). This interaction was verified by co-immunoprecipitation, and intracellular imaging revealed that Sp100 and HIV-1 IN partially colocalized. Furthermore, mutant variants assay indicated that the C-terminal 300～480 residues of Sp100 and the catalytic domain of HIV-1 IN were responsible for this interaction. Knocking down endogenous Sp100 with Sp100-specific siRNA increased HIV-1 IN-mediated integration. Conversely, overexpression of Sp100 by transient transfection decreased HIV-1 IN-mediated integration. This is the first time that Sp100 has been found to interact with HIV-1 IN and inhibit lentiviral vector integration. It reveals a new function of Sp100 as a HIV-1 IN-interacting protein and expands knowledge of the cellular defensive response to viral infection.

Abstract:The study was aimed to investigate the effects of human bone marrow mesenchymal stem cells (MSCs) in the radiation-induced intestinal injury. MSCs were expanded, labeled with enhance green fluorescentprotein (eGFP). The NOD/SCID mice were randomly assigned to one of three groups: (A) without radiation; (B) and (C) received abdominal radiation with 5 Gy ⁶⁰Co γ-rays at the rate of 100 cGy/min. (B) i.v. transplanted with physiological saline, (C) i.v. transplanted with MSCs. Mice were weighed daily and observed for 15 days after irradiation. Intestines of mice were obtained in order to assay histological changes by hematoxylin and eosin staining. The immunofluorescence staining showed that the transplanted cells could differentiate into vimentin+/α-SMA+ fibroblastic-like cells in vivo. These data indicated that MSCs could engraft at the injured small intestine, and contribute to the repairment of irradiated intestine. This could provide a valuable strategy for radiation-induced enteritis.

Abstract:Bloom syndrome helicase (BLM) is an important member of RecQ family of DNA helicases. It participates in cell metabolism including DNA repair, recombination, transcription, telomere maintenance, and plays key roles in maintaining chromosome stability. The mutation of BLM helicase may lead to Bloom syndrome that characterized by genomic instability and a strong predisposition to many types of cancer. This study was studied the interaction of BLM helicase catalytic core (BLM^642～1290) with double-stranded DNA (dsDNA) by fluorescence polarization technology, and analyzed the related characteristic parameters to understand the DNA-binding and unwinding properties of BLM^642～1290 helicase. The results indicated that the binding and unwinding of the helicase and dsDNA was related to the length of 3'-tailed single-stranded DNA (ssDNA) in dsDNA substrates; the helicase preferred to bind the ssDNA tails of dsDNA substrates, and every helicase molecule may bind 9.6 nt ssDNA; the unwinding efficiency was the highest level when the 3'-tail ssDNA length of dsDNA substrates was 10nt, no longer increasing with the length. In addition, the blunt dsDNA was also bound and unwound by BLM^642～1290 helicase, but the binding affinity and the unwinding efficiency were smaller than 3'-tailed dsDNA. It may be concluded that BLM^642～1290 helicase was monomer in binding and unwinding to dsDNA substrates, and may unwind dsDNA in an inchworm manner. These results will provide the theoretical foundation for further studying the unwinding mechanism of BLM helicase.

Abstract:For the assessment of the dynamic concentration of exogenous protein or peptide in serum, an antibody- independent sandwich system based on the avidin-biotin interaction was established and validated. The exogenous protein or polypeptide labeled with biotin was added to the microplate coated with streptavidin, and followed by adding HRP-streptavidin to complete the sandwich system. This sandwich system was validated with respect to specificity, sensitivity, accuracy (recovery) and reproducibility. While the sensitivity of detection could reach to 0.3125 μg/L, the sensitivity and the range of detection can also be adjusted by changing coating concentration of streptavidin. Recoveries ranged from 97.82% to 107.29%, and the intra- and inter-assay variation was < 5.76% and < 8.42%, respectively. Thus, the well-validated streptavidin sandwich system was successfully applied to determine dynamic concentrations of Biotin-HAS (human serum albumin) and Biotin-OVM (Ovomucoid) in mouse serum, respectively. Most importantly, this novel method, where generation of antibody or radionuclide is not needed, may provide a new choice for assessment or monitoring of exogenous protein or peptide in pharmacokinetics study.

Abstract:The change of intracellular adenosines concentration is the sensor of cellular energy metabolism changes, and it will contribute to monitor the effect of drugs on cellular energy metabolism with establishment of high performance liquid chromatography-tandem mass spectrometry to detect intracellular adenosines concentration. The adenosines of cells were extracted by ultrasonic extraction with perchloric acid containing Na-EDTA. The chromatographic separation was achieved with a UPLC HSS T3 column and waters containing 8 mmol/L N, N-dimethylhexylamine (DMHA) and acetonitrile as mobile phases at 0.25 ml/min flow rate. The identification and quantification were achieved by using ESI-MS/MS in positive ion and with multiple reactions monitoring (MRM) mode. With linear ranges of AMP ((0.1814～14.5164) μmol/L), ADP ((0.2342～18.7354) μmol/L) and ATP ((0.2003～16.0260) μmol/L), the external calibration method was well used for the quantitation, and the correlation coefficient of AMP, ADP and ATP were 0.9984, 0.9964 and 0.9990 respectively. The limit of detections (LOD, S/N > 3) of AMP, ADP and ATP were 1.9291, 1.8794 and 166.5 nmol/L, and their limit of quantifications (LOQ, S/N > 10) were 1.9632, 1.9672 and 185.6 nmol/L, respectively. The recoveries of the spiked standards varied from 81.8% to 107.8% with relative standard deviations (RSDs) less than 7.55%. The intraday precisions of AMP, ADP and ATP were 6.16%, 5.13% and 7.66%, and their interday precisions were 6.36%, 2.74% and 6.77%, respectively. The method was fast, simple, sensitive and suitable for the quantitative analysis of AMP, ADP and ATP in cell extracts. Analysis of AMP, ADP and ATP in human lung cancer A549 cells treated with different concentration volatile oils of Alpinia officinarum Hance, the results showed that the total level of cellular adenylate energy and ECP were decline with concentration dependence. The levels of ATP/TAN were decreased significantly when the concentration was 500 mg/L but the level of AMP/ATP in A549 cells were increased with concentration dependent. It was suggested that the volatile oils of Alpinia officinarum Hance inhibited cell proliferation by affecting the cellular energy metabolism.

Abstract:Mass spectrometry-based proteomics has developed rapidly, finding a method of quick, highly reproducible and accurate quantification is a great challenge in this research sphere. Quantitative proteomics as a new branch allows deeper insight into biological study. Recently, label-free quantification has been increasingly attractive for its simple sample preparation, low cost of reagents and clean results. Mass spectrometry-based label-free quantitative proteomics is generally divided into two categories, which are based on peptide chromatographic ion intensity and based on spectral counts. This review gives a general principle of these two label-free methods, presents a relatively complete summary of some commonly used label-free quantitative methods and their latest progress, and discusses the differences between the two methods and some challenges for label-free methods. We wish this review could provide a rational introduction of selecting label-free methods optimally suited to address your specific issue.