Abstract:Lipid metabolism is tightly regulated at the cellular level, in addition to classic transcriptional regulation of cholesterol metabolism (e.g. by SREBP and LXR). Members of a class of non-coding RNAs termed microRNAs have recently been identified to be potent post-transcriptional regulators of lipid metabolism genes, including metabolisms of cholesterol, triglyceride, and fatty acid. Several reports have recently shown that miR-33 regulates cholesterol efflux and HDL biogenesis by downregulating the expression of the ABC transporters, ABCA1 and ABCG1. Moreover, miR-33 also inhibits the translation of several transcriptional regulating proteins for fatty acid β-oxidation, including CPT1A, CROT, and HADHB, thereby inhibiting fatty acid degradation. In addition, miR-33 may regulates triglyceride metabolism through negatively regulating the activity of AMPK and RIP140. Other microRNAs including miR-122, miR-370, miR-125a-5p, miR-27 and miR-320 have been shown to play important roles in regulating cholesterol homeostasis, triglyceride, fatty acid metabolism and lipogenesis. The current progress of the microRNAs, especially miR-33, in regulating lipid metabolism were summarized.

Abstract:Neuronal restrictive silencing factor (NRSF), also known as repressor element-1 silencing transcription factor (REST), a Kruppel-type zinc finger protein, functions as a transcription regulator of a myriad of target genes through binding to a specific DNA sequence (repressor element-1/neuron-restrictive silencer element, RE-1/ NRSE). REST differentially influences target-gene expression through interaction with a wide variety of cellular cofactors in a context-dependent manner. Perturbations in the levels and functions of REST lead to various disorders. Recent studies have shown that REST is involves in multiple physiological processes such as maintaining pluripotency and self-renewal of embryonic stem cell and regulating the differentiation of stem cells into neuron or islet cells. The current understanding of NRSF/REST was presented, focusing on its roles in embryonic stem cell self-renewal, early embryonic development, neuron and islet cells diffentiation of stem cells.

Abstract:Beta cell dysfunction is a critical step in the pathogenesis of type 2 diabetes mellitus, while cellular cholesterol accumulation is an emerging mechanism for beta cell dysfunction in type 2 diabetes. Absence of the cholesterol transporter ATP-binding cassette transporter A1 (ABCA1) results in increased islet cholesterol and impaired insulin secretion, indicating that impaired cholesterol efflux leads to beta cell dysfunction.

Abstract:The year 2010 marks the sixtieth anniversary for the publication of Science in China series journals, and meanwhile the Science in China Series C: Life Sciences took a new name as Science China Life Sciences (SCLS in short). Simultaneously, it has been reformed to make a new start for this journal in its long history. The journal has appeared with a new face to the readers and authors in both the novel publishing style and the highly qualified articles. An extensive review was given to the journal's specific progress in the year 2010 by highlighting some of the representative publications.

Abstract:Galectins are a protein family with diverse biological functions, which are unique in specifically recognition and binding with β-galactosides as the primary structural basis for its functional performance. So far, all structurally characterized galectins display a conservative binding mode for the β-galactoside-containing carbohydrate ligands, in which one carbohydrate recognition domain (CRD) binds only one ligand. Here a novel binding pattern unique in two carbohydrate ligands for one CRD was reported, which is observed from the structure of Gal-3 CRD complexed with glycan TFN. In this doublet binding sites, Site 1 and Site 2, two TFN molecules interact with the CRD domain via two hydrogen-bond networks mediated by certain water molecules, respectively. The mutagenesis analysis shows that one of the binding sites, Site 1, is basic and essential for the carbohydrate ligands with a conservative binding mode, which should be commonly existed in galectins. While, the other binding site (Site 2) is easily discarded in a small structural interference from a single-site mutation, which illustrates that it should be conditionally appeared to play an additional and auxiliary role in ligand binding. The stereo-chemical analysis indicates that this doublet binding pattern may be suitable for some glycans with certain rather complicated constitutions, like branched structure. The possible functional role of this doublet binding pattern is also discussed.

Abstract:RNF122 is a novel gene which can inhibit cellular growth and induce apoptosis. RNF122 contains a RING-H2 domain. RING domain mutant was constructed to explore the relationship between RING domain and apoptosis. MTT and apoptosis experiments revealed that RNF122 closely related to cell viability dependent on its RING domain. Further exploration implied that RNF122 can negatively regulate ERK pathway, whereas RING domain mutant RNF122 can enhance the phosphorylation of ERK. It can be concluded that RNF122 may regulate cellular viability through ERK pathway. In short, RING domain is critical to the function of RNF122.

Abstract:In the nervous system, numerous feedforward and feedback circuits are formed by descending projections together with ascending inputs. It has been shown that the transmission and processing of neural signals are modulated by these extremely complicated pathways, but little is known about the functional roles of feedback projections in the cortex. Area posteromedial lateral suprasylvian (PMLS) in the extrastriate cortex of the cat was inactivated locally and reversibly by microinjection of inhibitory neurotransmitter GABA, and extracellular recording was performed to investigate the changes in visual response properties of neurons in the striate cortex. The PMLS inactivation resulted in an overall reduction in the responses of striate neurons to moving stimuli, accompanied by little change in the relative stability of responsiveness and a decline in the ratio of maximal firing rate to spontaneous activity level. In the meanwhile, the direction selectivity index decreased, but the change of orientation tuning strength was insignificant, the preferred direction kept unvaried except for a few bi-directional cells. Further analysis revealed that the neuronal responses were reduced in all the stimulus directions, but most largely in the preferred direction, which might serve as the key factor to weaken the direction selectivity. These findings indicate that the feedback projection from PMLS can enhance the direction selectivity of striate neurons but exert little effect on the orientation tuning. It appears that the feedback modulation is characterized by the important role of PMLS in visual motion processing in the cerebral cortex.

Abstract:The adeno-associated virus (AAV) has many safety features that favor its use in the treatment of arteriosclerosis; however, the conventional, adeno-associated virus (AAV) mediated single-gene delivery is inefficient for arteriosclerosis. This has been attributed that the incidence of atherosclerosis is caused by a variety of genetic defects but not a particular gene. To overcome this, double-gene delivery was evaluated for the treatment of atherosclerosis. Four experimental groups were administered the following AAV vector constructs: rAAV-apoAⅠ-IRES-SR-BⅠ, rAAV-apoAⅠ-GFP, rAAV-IRES-GFP, and PBS. ApoAⅠ and SR-BⅠ gene expression was detected using RT-PCR. The apoAⅠ and SR-BⅠ protein expression was determined by Western blotting and ELISA. Diet-induced hypercholesterolemia and atherosclerosis in rats was adopted and rAAV was administered through the tail vein injection. HepG2 cells were cultured and infected with the three viral vectors. The apoAⅠ and SR-BⅠ secreted from HepG2 cells in the AAV- apoAⅠ/SR-BⅠ group enhanced cholesterol efflux and resulted in a stronger RCT ability, respectively. In the rats' model with diet-induced hypercholesterolemia and atherosclerosis, GFP expression could be detected at 8 weeks post-injection. The rAAV vector had superior gene expressing activity. Eight weeks after gene transfer, plasma total cholesterol and LDL-cholesterol concentrations were significantly reduced (P < 0.05) compared to control for rAAV-IRES-GFP (AAV-GFP) treated group. No effect on HDL-cholesterol concentrations occurred. Ultrasound determined intima-media thickness also has been significantly reduced compared to control. Serum hs-CRP and SOD levels increased significantly (P < 0.01). Serum MDA levels decreased significantly. Gene mRNA expression was detected in atherosclerosis rats' model. The results show that rAAV-hapoAⅠ-IRES-hSR-BⅠ vector can anti-inflammatory, reduce atherosclerotic macrophage content and increases lesion stability of pre-existing plaques through quenching of NF-κB activity and reducing plasma cholesterol. Simultaneous over-expression of apoAⅠ and SR-BⅠ by AAV-mediated gene transfer may have a favorable effect on diet-induced hypercholesterolemia and arteriosclerosis in rats. These results may provide a new method for gene therapy of arteriosclerosis.

Abstract:Hyperplastic scar, a fibroproliferative disorder, complicates wound healing. Although the pathogenesis is not well understood, prolonged inflammation is a known contributing factor. Emerging evidence suggests that fibroblasts regulate immune/inflammatory responses through toll-like receptor 4(TLR-4) activated by lipopolysaccharide (LPS), leading to nuclear factor-κB (NF-κB) and mitogen-activated protein kinases (MAPK) activation, cytokine gene transcription and co-stimulatory molecule expression and resulting in inflammation. So the possible roles of TLR-4 in hyperplastic scar formation need to be explored. Paired normal and hyperplastic scar tissue was collected and dermal fibroblasts isolated and cultured. Quantitative RT-PCR of pairs of fibroblasts demonstrated mRNA levels for TLR4 and its legend myeloid differentiation factor 88 (MyD88) in hyperplastic scar fibroblasts (HSFB) were increased significantly compared with normal fibroblasts (NFB). When paired normal and HSFB were stimulated with LPS, significant increases in mRNA and protein levels for TLR-4, MyD88, transforming growth factor-beta1 (TGF-β1) and Ⅰ procollagen were detected. However, when transfected with MyD88 small interfering RNA (siRNA) in HSFB, then stimulated with LPS, a significant decrease in mRNA and protein levels for these molecules compared to only LPS-stimulated fibroblasts was detected. In comparison, a scramble siRNA transfection did not affect mRNA or protein levels for these molecules. Results demonstrate LPS stimulates proinflammatory cytokine expression in dermal fibroblasts and MyD88 siRNA eliminates the expression. Therefore, controlling inflammation and manipulating TLR signaling in skin cells may result in novel treatment strategies for hyperplastic scar.

Abstract:To detect whether Col-Ⅰ has some contribution to migration and proliferation of head and neck squamous carcinoma cell (HNSCC) in tumor microenvironment, transwells were applied to measure cell migration, cell velocity and cell scattering were analyzed by Zeiss Axiovert inverted microscope. The expression of E-cadherin as one of cell surface adhesion molecules and cell location of β-catenin were detected by Western blotting and/or immunofluorescence, then proliferation was analyzed by MTT and the PCNA expression. Results showed that Col-Ⅰ promoted cell metastasis, cell velocity and cell scattering, which E-cadherin was repressed possibly by the increased phosphorylation of β-catenin. The nuclear translocation of β-catenin led to an increasing expression of cyclin D1 and proliferation. Together, a conclusion is made that Col-Ⅰ promotes HNSCC metastasis via upregulation of phosphorylation of β-catenin and proliferation by the nuclear translocation of β-catenin.

Abstract:It is known that both FHC and Bim is involved in the regulation of intracellular iron metabolism, and plays a role in cellular apoptosis caused by ROS. However, the molecular mechanisms of FHC regulating apoptosis are remaining unknown. Using pLexA-Bim L as bait, a pB42AD based cDNA library was screened and FHC was identified as a Bim interacting protein. The interaction domain on Bim was located to BH3 domain. The interaction between FHC and Bim was further verified by co-immunoprecipitation. The subcellular location assay revealed that both Bim and FHC are located to cytoplasm and partially overlap. Over expression of FHC in HEK293 protects the cells from cytotoxity caused by over expressing Bim L. Both over-expression and knock-down analysis of FHC suggest that FHC protects HEK293 cells from hydrogen peroxide treatment. A novel Bim interacting protein, FHC was identified and it was suggested that FHC play a role in Bim mediated apoptosis and oxidative stress.

Abstract:The accurate classification of ERPs is very important for numerous human cognition studies and clinical evaluations. Extracting feature from ERPs is very important due to high dimension of ERPs which includes much information having nothing to do with classification. The principle and weakness of CSP were analyzed and the method to extract spatio-temporal feature by combining AR model and Whiten transformation was proposed. Cognitive experiments were designed to verify our method. Two kind of features were extracted from the data collected from the cognitive experiments separately by spatio-temporal method and CSP, the classifiers were trained both by SVM, and compared the two on effectiveness of classification were compared. The result demonstrates the spatio-temporal feature method is clearly superior to CSP in the classification of ERPs and the precision rate of classification based on spatio-temporal feature method may be over 90% if the parameters are reasonably determined.