C/EBPα negatively regulates SIRT7 expression via recruiting HDAC3 to the upstream-promoter of hepatocellular carcinoma cells.

Mammalian Sirtuin proteins (SIRTs) are homologs of yeast Sir2, and characterized as class III histone deacetylases of NAD(+) dependence. Unlike their lower counterparts that are directly involved in the extending of lifespan, mammalian SIRTs mainly function in metabolism and cellular homeostasis, among them, SIRT7 is the least understood. SIRT7 is localized in the nucleus and rich in nucleoli associated with RNA polymerase I, and correlated with cell proliferation. In contrast, SIRT7 has recently been demonstrated to specifically deacetylate H3K18ac in the chromatin, and in most cases represses proliferation. Although MicroRNA as miR-125b has been reported to down-regulate SIRT7 by binding to its 3'UTR, however, how SIRT7 gene is regulated remains unclear. Here, we identified the transcription initiation site of human SIRT7 gene at the upstream 23rd A nucleotide respective to the translational codon, and the SIRT7 is a TATA-less and initiator-less gene. The sequences in the upstream region between -256 and -129 bp are identical with important functions in the three species detected. A C/EBPα responding element is found that binds both C/EBPα and C/EBPß in vitro. We showed TSA induced SIRT7 gene transcription and only the HDAC3, but not its catalytic domain depleted mutant, interacted with C/EBPα to occupy the C/EBPα element and repressed SIRT7 gene in the hepatocellular carcinoma cells. To our knowledge, this is the first report on the regulation mechanism of SIRT7 gene, in which, HDAC3 collaborated with C/EBPα to occupy its responding element in the upstream region of SIRT7 gene and repressed its expression in human cells.

[Development Scenarios and Environmental Benefits Analysis of Future Power Generation Industry Under Two Modes in China].

In order to study the impact of the "carbon peak and neutrality" mode on future power generation and the environment in China, a Verhulst gray model was established to predict the development of the power generation industry from 2021 to 2060 under the non-"carbon peak and neutrality" mode. In addition, based on the "China 2030 Energy and Power Development Planning Research and 2060 Outlook Report," the development of the power generation industry from 2021 to 2060 under the "carbon peak and neutrality" mode was obtained, and the development scenarios of the future power generation industry in China under two models were compared and studied. The emission factors and emission reduction factors of CO2, SO2, NOx, PM, PM10, and PM2.5 were constructed through the conservation of elements and the generating performance standard, and then four environmental benefits A1-A4 were defined. The results showed that the installed capacity of thermal power will reach the carbon peak in 2026 under the "carbon peak and neutrality" mode. To achieve the carbon neutralization, the installed capacity of thermal power will be reduced by an average of 28 million kilowatts per year after 2026, and the installed capacity of renewable energy generated is required to increase by 154 million kilowatts per year after 2020. Compared with that in the non-"carbon peak and neutrality" mode, the installed capacity of thermal power generation will be greatly reduced, and the installed capacity of renewable energy power generation will be greatly increased under the "carbon peak and neutrality" mode, resulting in huge A1 and A2 environmental benefits. In the next four decades, the cumulative emission reductions in CO2, SO2, NOx, PM, PM10, and PM2.5 thermal power generation A1 are predicted to be 6.64×1010 tons, 1.54×107 tons, 1.55×107 tons, 3.18×106 tons, 1.71×106tons, and 2.23×105 tons, respectively. The cumulative emission reductions of renewable energy power generation A2 will be 5.77×1010 tons, 1.64×107 tons, 1.42×107 tons, 2.86×106 tons, 1.54×106 tons, and 2×105 t tons, respectively. Under the "carbon peak and neutrality" mode, compared with those from coal-fired power generation, the environmental benefits A3 and A4 produced by the relative cleanliness of renewable energy and nuclear power indicated that the cumulative emission reductions (A3+A4) in clean energy power generation of CO2, SO2, NOx, PM, PM10, and PM2.5 in the next four decades will be 3.014×1011 tons, 7.292×107 tons, 7.119×107 tons, 1.454×107 tons, 7.827×106tons, and 1.018×106 tons, respectively.

Jmjd3 activates Mash1 gene in RA-induced neuronal differentiation of P19 cells.

Covalent modifications of histone tails have fundamental roles in chromatin structure and function. Tri-methyl modification on lysine 27 of histone H3 (H3K27me3) usually correlates with gene repression that plays important roles in cell lineage commitment and development. Mash1 is a basic helix-loop-helix regulatory protein that plays a critical role in neurogenesis, where it expresses as an early marker. In this study, we have shown a decreased H3K27me3 accompanying with an increased demethylase of H3K27me3 (Jmjd3) at the promoter of Mash1 can elicit a dramatically efficient expression of Mash1 in RA-treated P19 cells. Over-expression of Jmjd3 in P19 cells also significantly enhances the RA-induced expression and promoter activity of Mash1. By contrast, the mRNA expression and promoter activity of Mash1 are significantly reduced, when Jmjd3 siRNA or dominant negative mutant of Jmjd3 is introduced into the P19 cells. Chromatin immunoprecipitation assays show that Jmjd3 is efficiently recruited to a proximal upstream region of Mash1 promoter that is overlapped with the specific binding site of Hes1 in RA-induced cells. Moreover, the association between Jmjd3 and Hes1 is shown in a co-Immunoprecipitation assay. It is thus likely that Jmjd3 is recruited to the Mash1 promoter via Hes1. Our results suggest that the demethylase activity of Jmjd3 and its mediator Hes1 for Mash1 promoter binding are both required for Jmjd3 enhanced efficient expression of Mash1 gene in the early stage of RA-induced neuronal differentiation of P19 cells.

[Inhibitory role of SirT7 in the growth of P19 cell line].

OBJECTIVE: To study the regulatory role of SirT7, one of class histone deacetylases, on the proliferation of mouse embryonal carcinoma cell line P19. METHODS: We used an expression plasmid of SirT7 (151-402 amino acid residues) and its vector respectively to establish a stably expressed SirT7 and its control P19 cell lines. Recombinant DNA techniques, Western blot, cell growth curve, and flow cytometry were used in this paper. RESULTS: Compared with the control cells, the P19 cells had significantly lower growth rate in stably expressed SirT7. G1 to S cell cycle arrests were only seen in the SirT7 over-expressed cell line. CONCLUSION: SirT7 play a dominant role in the grow inhibition of the P19 cells.

[Protective effects of Denghuang injection on cerebral infarction in animal].

OBJECTIVE: To observe the protective effects of Denghuang injection on cerebral infarction in animal. METHOD: The study evaluated the protective effects of Denghuang injection on cerebral infarction through 3 experiments: 1. ligating the arteria cerebri media of dog; 2. blocking the internal carotid artery of rat; 3. ligating the common carotiol artery of gerbil. RESULT: The results showed Denghuang injection could reduce the cerebral infarction area after the dog's arteria cerebri media was ligated, and also could restrain the AKP&CK increase. The injection could reduce the cerebral infarction area of rat after the internal carotid artery was bloked by thrombus, and the mark of behavior and nerve symptom was better than that in the control group. Denghuang injection could obviously reduce the water content in pallium of gerbil after the common carotiol artery was ligated, and also could increase the amount of living pyramidal neuron in hippocampus, and reduce the MDA&LDH increase in pallium slurry. CONCLUSION: Denghuang injection can obviously protect animal on cerebral infarction.

KrF excimer laser precision machining of hard and brittle ceramic biomaterials.

KrF excimer laser precision machining of porous hard-brittle ceramic biomaterials was studied to find a suitable way of machining the materials into various desired shapes and sizes without distorting their intrinsic structure and porosity. Calcium phosphate glass ceramics (CPGs) and hydroxyapatite (HA) were chosen for the study. It was found that KrF excimer laser can cut both CPGs and HA with high efficiency and precision. The ablation rates of CPGs and HA are respectively 0.081 µm/(pulse J cm(-2)) and 0.048 µm/(pulse J cm(-2)), while their threshold fluences are individually 0.72 and 1.5 J cm(-2). The cutting quality (smoothness of the cut surface) is a function of laser repetition rate and cutting speed. The higher the repetition rate and lower the cutting speed, the better the cutting quality. A comparison between the cross sections of CPGs and HA cut using the excimer laser and using a conventional diamond cutting blade indicates that those cut by the excimer laser could retain their intrinsic porosity and geometry without distortion. In contrast, those cut by conventional machining had distorted geometry and most of their surface porosities were lost. Therefore, when cutting hard-brittle ceramic biomaterials to prepare scaffold and implant or when sectioning them for porosity evaluation, it is better to choose KrF excimer laser machining.

[Coal fineness effect on primary particulate matter features during pulverized coal combustion].

Three kinds of coal differed from fineness were burned in a laboratory-scale drop tube furnace for combustion test, and an 8-stage Andersen particle impactor was employed for sampling the primary particulate matter (PM), in order to study coal fineness effect on primary PM features during pulverized coal combustion. It has been shown that the finer the coal was, the finer the PM produced. PM, emission amount augmented with coal fineness decreased, and the amount of PM10 increased from 13 mg/g to 21 mg/g respectively generated by coarse coal and fine coal. The amount of PM2.5 increased from 2 mg/g to 8 mg/g at the same condition. Constituents and content in bulk ash varied little after three different fineness coal combustion, while the appearance of grading PM differed visibly. The value of R(EE) increased while the coal fineness deceased. The volatility of trace elements which were investigated was Pb > Cr > Zn > Cu > Ni in turn. The concentration of poisonous trace elements was higher which generated from fine coal combustion. The volatilization capacity was influenced little by coal fineness, but the volatilization extent was influenced differently by coal fineness. Fine coal combustion affects worse environment than coarse coal does.

Sequential recruitment of PCAF and BRG1 contributes to myogenin activation in 12-O-tetradecanoylphorbol-13-acetate-induced early differentiation of rhabdomyosarcoma-derived cells.

Myogenin and its upstream regulator MyoD are known to be required for myogenic cell differentiation. Although both of them can be expressed in rhabdomyosarcoma-derived RD cells, the cells are unable to undergo full-scale terminal myogenic differentiation. 12-O-Tetradecanoylphorbol-13-acetate (TPA) has been found to be functional in the induction of RD cell differentiation, whereas its mechanism is not fully understood. By using quantitative real-time-based chromatin immunoprecipitation and real-time reverse transcription-PCR-based promoter activity assays, we examined the activation mechanism of the myogenin gene during TPA-induced differentiation of the RD cells. We have shown that a histone acetyltransferase PCAF and ATPase subunit BRG1 of the SWI/SNF chromatin remodeling complex are sequentially recruited to the promoter of the myogenin gene. Both PCAF and BRG1 are also involved in the activation of the myogenin gene. In addition, we have found that the p38 mitogen-activated protein kinase is required for BRG1 recruitment in TPA-mediated myogenin induction. We propose that there are two distinct activation steps for the induction of myogenin in TPA-induced early differentiation of RD cells: 1) an early step that requires PCAF activity to acetylate core histones and MyoD to initiate myogenin gene expression, and 2) a later step that requires p38-dependent activity of the SWI/SNF remodeling complex to provide an open conformation for the induction of myogenin. Our studies reveal an essential role for epigenetic regulation in TPA-induced differentiation of RD cells and provide potential drug targets for future treatment of the rhabdomyosarcoma.