Mechanism of HBx Protein Inhibiting DKK4 Expression and Its Effect on Proliferation and Migration of Hepatocarcinoma Cell Lines / 肿瘤防治研究

Objective To explore the mechanism of hepatitis B virus X protein down-regulating DKK4 and its effect on the proliferation, migration of HCC cell lines. Methods HCC cell lines HepG2 and SMMC7721 cells were infected with adenovirus encoding hepatitis B virus X protein (Ad-HBx), and GFP adenovirus (Ad-GFP) was designed as a control group. We used deacetylase inhibitor (TSA) to treat HCC cell lines and transfected HCC cell lines with small interfering RNA-histone deacetylase 1 (si-HDAC1) and lentivirus overexpressing DKK4. Western blot was used to detect the expression of DKK4, HDAC1 and SIRT1. The proliferation and migration ability of HCC lines were assessed using MTT, crystal violet experiment and Transwell experiment. Results DKK4 expression level was significantly downregulated after Ad-HBx infection (P < 0.05), and its expression level was recovered after TSA treatment (P < 0.05). After silencing HDAC1 with small interfering RNA, the expression of DKK4 could be restored (P < 0.05), the proliferation and migration of HDAC1-silencing or/and DKK4-overexpressing cells decreased (P < 0.05). Conclusion Hepatitis B virus X protein inhibits the expression of DKK4 protein by up-regulating HDAC1 and SIRT1. Silencing HDAC1 and over expressing DKK4 protein could inhibit the proliferation and migration of HCC cell lines infected with Ad-HBx.

Role of NAD +-mediated deacetylation activity of SIRT1 in endotoxin-induced acute lung injury in mice / 中华麻醉学杂志

Objective:To evaluate the role of nicotinamide adenine dinucleotide (NAD + )-mediated deacetylation activity of silent information regulator 1 (SIRT1) in endotoxin-induced acute lung injury (ALI) in mice. Methods:Twenty-five SPF clean-grade healthy male C57BL/6 mice including 10 wild-type (WT) and 15 NMNAT1 conditional-knockout (KO) mice, aged 6-8 weeks, weighing 20-25 g, were selected.The WT mice were divided into 2 groups ( n=5 each) using a random number table method: control group (group WT+ C) and ALI group (group WT+ ALI). The KO mice were divided into 3 groups ( n=5 each) using a random number table method: control group (group KO+ C), ALI group (group KO+ ALI) and ALI plus NAD + precursor substances nicotinamide mononucleotide (NMN) group (KO+ LPS+ NMN group). ALI was produced with lipopolysaccharide (LPS) 15 mg/kg injected intravenously.NMN 500 mg/kg was intraperitoneally injected at 1 h before injection of LPS in KO+ ALI+ NMN group, while the equal volume of normal saline was given instead in control group.Blood samples were collected from the abdominal aorta at 12 h after LPS or normal saline injection for blood gas analysis, and the animals were then sacrificed and the lung tissues were removed for microscopic examination of pathologic changes which were scored and for determination of wet/dry weight ratio (W/D ratio), and interleukin-6 (IL-6), IL-1β and tumor necrosis factor-alpha (TNF-α) contents (by enzyme-linked immunosorbent assay)and content of NAD + (using a spectrophotometer) and levels of SIRT1, acetylated nuclear factor kappaB (Ac-NF-κB), acetylated p53 (Ac-p53), acetylated FoxO1 (Ac-FoxO1) and acetylated PGC1α (Ac-PGC1α) (by Western blot). Results:Compared with group C, pH value and PaO 2 were significantly decreased, the PaCO 2, W/D ratio, lung injury score, contents of IL-6, IL-1β, TNF-α and NAD + were increased, expression of SIRT1 was up-regulated, and expression of Ac-NF-κB, Ac-p53, Ac-FoxO1 and Ac-PGC1α was down-regulated in group ALI ( P<0.05). Compared with group WT+ ALI, pH value and PaO 2 were significantly decreased, the PaCO 2, W/D ratio, lung injury score, contents of IL-6, IL-1β and TNF-α were increased, NAD + content was decreased, expression of SIRT1 was down-regulated, and expression of Ac-NF-κB, Ac-p53, Ac-FoxO1 and Ac-PGC1α was up-regulated in group KO+ ALI ( P<0.05). Compared with group KO+ ALI, pH value and PaO 2 were significantly increased, the PaCO 2, W/D ratio, lung injury score, contents of IL-6, IL-1β and TNF-α were decreased, NAD + content was increased, expression of SIRT1 was up-regulated, and expression of Ac-NF-κB, Ac-p53, Ac-FoxO1 and Ac-PGC1α was down-regulated in group KO+ ALI+ NMN ( P<0.05). Conclusion:The enhanced NAD + -mediated deacetylation activity of SIRT1 is involved in the endogenous protective mechanism in mice with endotoxin-induced ALI.

A novel SIRT6 activator ameliorates neuroinflammation and ischemic brain injury

Ischemic stroke is the second leading cause of death worldwide with limited medications and neuroinflammation was recognized as a critical player in the progression of stroke, but how to control the overactive neuroinflammation is still a long-standing challenge. Here, we designed a novel SIRT6 activator MDL-811 which remarkably inhibited inflammatory response in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages and primary mouse microglia, which were abolished by silencing SIRT6. RNA-seq screening identified the forkhead box C1 (

Histone deacetylase 3 promotes innate antiviral immunity through deacetylation of TBK1

TANK-binding kinase 1 (TBK1), a core kinase of antiviral pathways, activates the production of interferons (IFNs). It has been reported that deacetylation activates TBK1; however, the precise mechanism still remains to be uncovered. We show here that during the early stage of viral infection, the acetylation of TBK1 was increased, and the acetylation of TBK1 at Lys241 enhanced the recruitment of IRF3 to TBK1. HDAC3 directly deacetylated TBK1 at Lys241 and Lys692, which resulted in the activation of TBK1. Deacetylation at Lys241 and Lys692 was critical for the kinase activity and dimerization of TBK1 respectively. Using knockout cell lines and transgenic mice, we confirmed that a HDAC3 null mutant exhibited enhanced susceptibility to viral challenge via impaired production of type I IFNs. Furthermore, activated TBK1 phosphorylated HDAC3, which promoted the deacetylation activity of HDAC3 and formed a feedback loop. In this study, we illustrated the roles the acetylated and deacetylated forms of TBK1 play in antiviral innate responses and clarified the post-translational modulations involved in the interaction between TBK1 and HDAC3.

Progress in roles and mechanisms of deacetylase SIRT7 / 生物工程学报

As a member of the Sirtuins family in mammals, SIRT7 locates in nucleus and is a highly specific H3K18Ac (acetylated lysine 18 of histone H3) deacetylase. Recent studies showed that SIRT7 could participate in the ribosomal RNA transcription, cell metabolism, cell stress and DNA damage repair through various signaling pathways. In addition, SIRT7 is also closely related with aging, heart disease and fatty liver. In particular, SIRT7 plays important roles in the regulation of initiation and development of various tumors, such as liver cancer, gastric cancer, breast cancer, bladder cancer, colorectal cancer, and head/neck squamous cell carcinoma. This review describes the cellular and molecular functions of SIRT7, and systematically summarizes recent progress of SIRT7 in human disease.

SIRT1 signaling pathway in bone metabolism / 上海交通大学学报（医学版）

Osteoporosis is a bone disease characterized by low bone mass and deteriorated bone microstructure, which could be related to the disorders of energy metabolism and bone senescence. Silent mating-type information regulator 2 homolog 1 (SIRT1) is a nicotinamide adenine dinucleotide (NAD+)-dependent deacetylase that regulates cell senescence, energy metabolism and bone remodeling. SIRT1 could be activated not only by adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK), c-Jun N-terminal kinase 1 (JNK1) and casein kinase 2 (CK2), but also by small-molecular drugs such as resveratrol. All these kinases and drugs can affect bone metabolism. Recent findings indicate that SIRT1 signaling pathway plays a direct role in bone metabolism, but the underlying mechanism remains unclear. This paper reviews the structure and function of SIRT1, and the role of SIRT1 in bone metabolism, and discusses the potential of SIRT1 signaling pathway as a new therapeutic target in osteoporosis.

Research progress of SIRT6 in cardiovascular diseases / 中国药理学通报

Cardiovascular disease is a serious disease harmful to human health with high morbidity and high mortality.SIRT6 plays an important role in cardiovascular diseases such as atherosclerosis,myocardial infarction and ischemia/reperfusion injury,pathological cardiac hypertrophy and heart failure,as an important member of the histone deacetylase family.In this paper,the role of SIRT6 in cardiovascular diseases is reviewed,and the development of SIRT6 as a target agonist and inhibitor is summarized.

Botulinum neurotoxin serotype A heavy chain intervenes in the H3 acetylation: A preliminary study / 中国比较医学杂志

Objective To investigate the effect and molecular mechanism of botulinum neurotoxin serotype A (BoNT/A) heavy chain on neuron regeneration. Methods Cell culture, rats, immunofluorescence, SDS-PAGE and western blot, etc. were adopted in this study to explore the alterations of histone-3 acetylation (acetyl-H3 ) by local treatment of BoNT/A heavy chain to spinal cord injury (SCI) in rats (in vivo) or by adding it into cell culture (in vitro). Meanwhile, the relevance of acetyl-H3 to neurite out-growth based on SCI and cell culture with BoNT/A heavy chain application was approached as well. Results The application of BoNT/A heavy chain to cultured Neuro-2a cells increased the level of H3 acetylation. The increase of H3 acetylation was paralleled with the growth of neuritogenesis. Also, the neuronal treatment of BoNT/A heavy chain to SCI promoted the re-growth of neuronal processes surrounding the lesions. The growth of neuronal processes was positively correlated to the level of H3 acetylation. During the periods of BoNT/A heavy chain treatment in vivo or in vitro, the increase of H3 acetylation showed two peaks. Conclusions BoNT/A heavy chain increased the H3 acetylation, which might be one of its neuritogenic mechanisms.

The structure of histone deacetylase 2 and its role in diseases / 中国比较医学杂志

Histone acetylation is one of the most important reactions of post-translational modification of histones, which plays an important role in the regulation of epigenetic processes. Histone deacetylase 2 as a member of type I histone deacetylases,involved in the catalytic regulation of histone and a variety of non-histone deacetylation,regulates a variety of life processes. This paper summarizes the basic structure of histone deacetylase 2 and the role of histone deacetylase 2 in various diseases,and provides a theoretical basis for conducting related studies.

Deacetylation of TFEB promotes fibrillar Aβ degradation by upregulating lysosomal biogenesis in microglia

Microglia play a pivotal role in clearance of Aβ by degrading them in lysosomes, countering amyloid plaque pathogenesis in Alzheimer's disease (AD). Recent evidence suggests that lysosomal dysfunction leads to insufficient elimination of toxic protein aggregates. We tested whether enhancing lysosomal function with transcription factor EB (TFEB), an essential regulator modulating lysosomal pathways, would promote Aβ clearance in microglia. Here we show that microglial expression of TFEB facilitates fibrillar Aβ (fAβ) degradation and reduces deposited amyloid plaques, which are further enhanced by deacetylation of TFEB. Using mass spectrometry analysis, we firstly confirmed acetylation as a previously unreported modification of TFEB and found that SIRT1 directly interacted with and deacetylated TFEB at lysine residue 116. Subsequently, SIRT1 overexpression enhanced lysosomal function and fAβ degradation by upregulating transcriptional levels of TFEB downstream targets, which could be inhibited when TFEB was knocked down. Furthermore, overexpression of deacetylated TFEB at K116R mutant in microglia accelerated intracellular fAβ degradation by stimulating lysosomal biogenesis and greatly reduced the deposited amyloid plaques in the brain slices of APP/PS1 transgenic mice. Our findings reveal that deacetylation of TFEB could regulate lysosomal biogenesis and fAβ degradation, making microglial activation of TFEB a possible strategy for attenuating amyloid plaque deposition in AD.

Treatment with 1,25(OH)2D3 induced HDAC2 expression and reduced NF-κB p65 expression in a rat model of OVA-induced asthma

Recent evidence indicates that a deficiency of 1,25-dihydroxyvitamin D3 (1,25[OH]2D3) may influence asthma pathogenesis; however, its roles in regulating specific molecular transcription mechanisms remain unclear. We aimed to investigate the effect of 1,25(OH)2D3 on the expression and enzyme activity of histone deacetylase 2 (HDAC2) and its synergistic effects with dexamethasone (Dx) in the inhibition of inflammatory cytokine secretion in a rat asthma model. Healthy Wistar rats were randomly divided into 6 groups: control, asthma, 1,25(OH)2D3 pretreatment, 1,25(OH)2D3 treatment, Dx treatment, and Dx and 1,25(OH)2D3 treatment. Pulmonary inflammation was induced by ovalbumin (OVA) sensitization and challenge (OVA/OVA). Inflammatory cells and cytokines in the bronchoalveolar lavage (BAL) fluid and histological changes in lung tissue were examined. Nuclear factor kappa B (NF-κB) p65 and HDAC2 expression levels were assessed with Western blot analyses and quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR). Enzyme activity measurements and immunohistochemical detection of HDAC2 were also performed. Our data demonstrated that 1,25(OH)2D3 reduced the airway inflammatory response and the level of inflammatory cytokines in BAL. Although NF-κB p65 expression was attenuated in the pretreatment and treatment groups, the expression and enzyme activity of HDAC2 were increased. In addition, 1,25(OH)2D3 and Dx had synergistic effects on the suppression of total cell infusion, cytokine release, and NF-κB p65 expression, and they also increased HDAC2 expression and activity in OVA/OVA rats. Collectively, our results indicated that 1,25(OH)2D3 might be useful as a novel HDAC2 activator in the treatment of asthma.

Comparative evaluation of doxofylline and theophylline in patients of mild bronchial asthma.

Background: Asthma is common chronic disease worldwide. Methylxanthines has been used in the treatment of asthma. The study was undertaken to compare two Methylxanthines theophylline and doxofylline at doses recommended and commonly used in clinical practice in Mild Bronchial Asthma Patients. Methods: Study was conducted in patients of Mild Bronchial Asthma in TB and chest disease department of a medical college hospital. It was randomized, prospective and open label. A total of 107 patients were divided in two group .Group I was administered 400 mg theophylline SR once daily and group II was administered doxofylline 400 mg twice a day orally. Spirometric variables symptom score, and adverse effects were recorded on day 0, 7 and 21 of therapy. Data were compared and analysed using SPSS version 16. Results: Results of the study showed that there was significant improvement in spirometric variables and clinical symptom score compared to pretreatment values after medication in both groups on 7th and 21st days of treatment. But there was no statistically significant difference between improvement in theophylline and doxofylline groups with respect to spirometric variables and symptom score. There was no significant difference in two groups with respect to side effects (p>0.05). Conclusions: It is concluded in Patients of mild Bronchial Asthma Theophylline and doxofylline improve the spirometric and clinical symptoms and doxofylline has no advantage over theophylline in terms of either efficacy or safety on the doses commonly used in current clinical practice.

Expression of HAT1 and HDAC1, 2, 3 in Diffuse Large B-Cell Lymphomas, Peripheral T-Cell Lymphomas, and NK/T-Cell Lymphomas

BACKGROUND: It has generally been proven that histone acetylation and deacetylation are involved in the malignant transformation. To date, however, this has rarely been studied in cases of malignant lymphoma. METHODS: We studied nine cases of reactive lymphoid hyperplasia, 78 cases of diffuse large B-cell lymphoma (DLBCL), 13 cases of peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS), and 13 cases of extranodal NK/T-cell lymphoma, nasal type (NKTCL). Thus, we attempted to elucidate the associations of the degree of the expression of histone acetyltransferase 1 (HAT1), histone deacetylase (HDAC) 1, HDAC2, and HDAC3 with the clinical behaviors of above malignant lymphomas using the immunohistochemistry and a western blot analysis. RESULTS: The degree of the expression of HAT1 was higher in cases of DLBCL, PTCL-NOS or NKTCL as compared with reactive lymphoid hyperplasia (p0.05). CONCLUSIONS: HAT1, HDAC1, and HDAC2 play a critical role in the development of malignant lymphomas. Both HAT1 and HDAC1 might be indicators for a poor prognosis in cases of DLBCL as cooperating factors.

Regulation of adipogenesis by nucelar receptor PPARγ is modulated by the histone demethylase JMJD2C

A potential strategy to combat obesity and its associated complications involves modifying gene expression in adipose cells to reduce lipid accumulation. The nuclear receptor Peroxisome Proliferator-activated receptor gamma (PPARγ) is the master regulator of adipose cell differentiation and its functional activation is currently used as a therapeutic approach for Diabetes Mellitus type 2. However, total activation of PPARγ induces undesirable secondary effects that might be set with a partial activation. A group of proteins that produce histone demethylation has been shown to modify the transcriptional activity of nuclear receptors. Here we describe the repressive action of the jumonji domain containing 2C/lysine demethylase 4 C (JMJD2C/KDM4C) on PPARγ transcriptional activation. JMJD2C significantly reduced the rosiglitazone stimulated PPARγ activation. This effect was mainly observed in experiments performed using the Tudor domains that may interact with histone deacetylase class 1 (HDAC) and this interaction probably reduces the mediated activation of PPARγ. Trichostatin A, a HDAC inhibitor, reduces the repressive effect of JMJD2C. When JMJD2C was over-expressed in 3T3-L1 cells, a reduction of differentiation was observed with the Tudor domain. In summary, we herein describe JMJD2C-mediated reduction of PPARgamma transcriptional activation as well as preadipocyte differentiation. This novel action of JMJD2C might have an important role in new therapeutic approaches to treat obesity and its complications.

Recovery of Genes Epigenetically Altered by the Histone Deacetylase Inhibitor Scriptaid and Demethylating Agent 5-Azacytidine in Human Leukemia Cells

Histone deacetylation and demethylation are epigenetic mechanisms implicated in cancer. Studies regarding the role of modulation of gene expression utilizing the histone deacetylase inhibitor scriptaid and the demethylating agent 5-azacytidine in HL-60 leukemia cells have been limited. We studied the possibility of recovering epigenetically silenced genes by scriptaid and 5-azacytidine in human leukemia cells by DNA microarray analysis. The first group was leukemia cells that were cultured with 5-azacytidine. The second group was cultured with scriptaid. The other group was cultured with both agents. Two hundred seventy newly developed genes were expressed after the combination of 5-azacytidine and scriptaid. Twenty-nine genes were unchanged after the combination treatment of 5-azacytidine and scriptaid. Among the 270 genes, 13 genes were differed significantly from the control. HPGD , CPA3, CEACAM6, LOC653907, ETS1, RAB37, PMP22, FST, FOXC1, and CCL2 were up-regulated, and IGLL3, IGLL1, and ASS1 were down-regulated. Eleven genes associated with oncogenesis were found among the differentially expressed genes: ETS1, ASCL2, BTG2, BTG1, SLAMF6, CDKN2D, RRAS, RET, GIPC1, MAGEB, and RGL4. We report the results of our leukemia cell microarray profiles after epigenetic combination therapy with the hope that they are the starting point of selectively targeted epigenetic therapy.

Dissolution test of various low-dose acetylsalicylic acid preparations marketed in Indonesia.

Aim To compare the dissolution profi les of various enteric-coated low-dose acetylsalicylic acid (ASA) tablets marketed in Indonesia. Methods The dissolution study was carried out according to US Pharmacocopoeiae (USP) /European Pharmacopoeiae, method A, using USP apparatus 1 (basket) 100 rpm, with 2 media: 0.1 N HCl, 120 minutes for acid stage, and phosphate buffer pH 6.8, 90 minutes for buffer stage. The sampling points were 120 minutes for the acid stage, and every 10 minutes until 90 minutes for the buffer stage. The acetylsalicylic acid was assayed using spectrophotometry at 280 nm for the acid stage, and at 265 nm for the buffer stage. The free salicylic acid was determined only at the end of the buffer stage with HPLC method. There were 6 test products (Cardio Aspirin® 100 mg, Aptor® 100 mg, Ascardia® 80 mg, Thrombo Aspilet® 80 mg, Astika® 100 mg and Farmasal® 100 mg), 3 batches for each product, and 6 units for each batch Results The amount of ASA released from each ASA product tested at the end of acid stage (120 minutes) ranged from 1.79% for Cardio Aspirin® to 6.92% for Thrombo Aspilet®, all conformed to the compendial requirement for enteric-coated product (< 10%). The amount of salicylic acid observed at the end of the dissolution test ranged from 3.47% for Cardio Aspirin® to 10.90% for Astika® and 11.90 % for Thrombo Aspilet®. Thrombo Aspilet® showed sustained-release properties, causing high variability in ASA release, such that one of the 3 batches tested did not fulfi ll the compendial requirement of more than 75% (the release was only 55.11%). High variability in ASA release between batches was also found with Farmasal® at 10, 20, and 30 minutes in buffer medium. The lowest effective dose of ASA as an antiplatelet drug for longterm use is 75 mg of plain ASA, and this is equivalent to 100 mg of enteric-coated ASA. Conclusions All of the low-dose ASA preparations marketed in Indonesia are enteric-coated products, while Thrombo Aspilet® is not only an enteric-coated but also a sustained-release product. Cardio Aspirin®, followed by Aptor®, has the right dose for low-dose enteric-coated preparation (100 mg), produces consistent ASA release between batches, and the most stable towards deacetylation (antiplatelet inactivation).

Curcumin-induced Histone Acetylation in Malignant Hematologic Cells / 华中科技大学学报（医学）（英德文版）

This study investigated the inhibitory effects of curcumin on proliferation of hemato-logical malignant cells in vitro and the anti-tumor mechanism at histone acetylation/histone deacety-lation levels.The effects of curcumin and histone deacetylase inhibitor trichostatin A (TSA) on the growth of Raji cells were tested by MTT assay.The expression of acetylated histone-3 (H3) in Raji,HL60 and K562 cells,and peripheral blood mononuclear cells (PBMCs) treated with curcumin or TSA was detected by immunohistochemistry and FACS.The results showed curcumin inhibited pro-liferation of Raji cells significantly in a time- and dose-dependent fashion,while exhibited low toxic-ity in PBMCs.Curcumin induced up-regulation of the expression of acetylated H3 dose-dependently in all malignant cell lines tested.In conclusion,curcumin inhibited proliferation of Raji cells selec-tively,enhanced the level of acetylated H3 in Raji,HL60,and K562 cells,which acted as a histone deacetylase inhibitor like TSA.Furthermore,up-regulation of H3 acetylation may play an important role in regulating the proliferation of Raji cells.

Expression of Sodium/iodide Symporter Transgene in Neural Stem Cells / 대한핵의학회잡지

PURPOSE: The ability to noninvasively track the migration of neural progenitor cells would have significant clinical and research implications. We generated stably transfected F3 human neural progenitor cells with human sodium/iodide symporter (hNIS) for noninvasively tracking F3. In this study, the expression patterns of hNIS gene in F3-NIS were examined according to the cultured time and the epigenetic modulation. MATERIALS AND METHODS: F3 human neural stem cells had been obtained from Dr. Seung U. Kim (Ajou University, Suwon, Korea). hNIS and hygromycin resistance gene were linked with IRES (Internal Ribosome Entry Site) under control of CMV promoter. This construct was transfected to F3 with Liposome. To investigate the restoration of hNIS gene expression in F3-NIS, cells were treated with demethylating agent (5-Azacytidine) and Histone deacetylase inhibitor (Trichostatin A: TSA). The expression of hNIS was measured by I-125 uptake assay and RT-PCR analysis. RESULTS: The iodide uptake of the F3-NIS was higher 12.86 times than F3 cell line. According to the cell passage number, hNIS expression in F3-NIS gradually diminished. After treatment of 5-Azacytidine and TSA with serial doses (up to 20micro M, up to 62.5nM, respectively) for 24 hours, I-125 uptake and mRNA of hNIS in F3-NIS were increased. CONCLUSION: These results suggest that hNIS transfected F3 might undergo a change in its biological characters by cell passage. Therefore, the gene expression of exogenous gene transferred human stem cell might be affected to the epigenetic modulation such as promoter methylation and Histone deacetylation and to the cell culture conditions.

Research on the hemostasis effect of chitos an's structure / 医疗卫生装备

The effects of chitosan and N,O-carboxymethyl chitosan on blood hemostasis are tested.The dynamic blood coagulation experiments show chitsan with low deacetylation degree has higher absorption ability.The experiments can't find that any altered red blood cell morphology or an unusual affinity between erythrocytes appears evidently in the ACD blood treated with chitosan.The concentration of the platelets on the chitosan surface may be one of causes that platelets produce blood coagulation.Chitosan is substituted by the carboxymethyl and has water solubility.But N,O-carboxymethyl chitosan can lead torouleau and not toaltering the morphology of the erythrocyte.The blood hemostasis effect is not obvious.The values of TT,PT,APTT and FIB are measured from blood and the results fail toprove that chitosan and N,O-carboxymethyl chitosan can activate the coagulation factors.

Mechanism of SIRT1 acting on tumor formation / 医学研究生学报

SIRT1 is an NAD+-dependent histone deacetylase,involved in many physiological processes,such as cell aging,apoptosis and differentiation.Recent studies have shown that SIRT1 plays a significant role in tumor formation and progression.It deacetylates a wide range of histone and non-histone substrates and regulates gene expression and protein activity that are associated with neoplastic apoptosis and proliferation.