Role of sirtuin 5 in cardiovascular diseases / 中国药理学通报

Cardiovascular diseases ( CVDs ) are the leading cause of death worldwide and pose a serious threat to human health. Silent information regulator 5 ( SIRT5 ) , which is widely distributed in cardiac myocytes, vascular smooth muscle cells and endothelial cells,as a novel deacylation-modifying enzyme,plays an important role in CVDs through deacetylation, desuccinylation and demalonylation. This review summarizes the pathophysiolog-ical mechanism of SIRT5 from the aspects of energy metabolism, regulation of inflammatory response and oxidative stress, apart from the role of SIRT5 in CVDs such as myocardial infarction, myocardial hypertrophy, arrhythmia, atherosclerosis and heart failure. This review also figures out the current research progress of SIRT5 -related inhibitors and agonists, so as to provide strategies for targeting SIRT5 to prevent and treat CVDs.

Sodium butyrate activates HMGCS2 to promote ketone body production through SIRT5-mediated desuccinylation / 医学前沿

Ketone bodies have beneficial metabolic activities, and the induction of plasma ketone bodies is a health promotion strategy. Dietary supplementation of sodium butyrate (SB) is an effective approach in the induction of plasma ketone bodies. However, the cellular and molecular mechanisms are unknown. In this study, SB was found to enhance the catalytic activity of 3-hydroxy-3-methylglutaryl-CoA synthase 2 (HMGCS2), a rate-limiting enzyme in ketogenesis, to promote ketone body production in hepatocytes. SB administrated by gavage or intraperitoneal injection significantly induced blood ß-hydroxybutyrate (BHB) in mice. BHB production was induced in the primary hepatocytes by SB. Protein succinylation was altered by SB in the liver tissues with down-regulation in 58 proteins and up-regulation in 26 proteins in the proteomics analysis. However, the alteration was mostly observed in mitochondrial proteins with 41% down- and 65% up-regulation, respectively. Succinylation status of HMGCS2 protein was altered by a reduction at two sites (K221 and K358) without a change in the protein level. The SB effect was significantly reduced by a SIRT5 inhibitor and in Sirt5-KO mice. The data suggests that SB activated HMGCS2 through SIRT5-mediated desuccinylation for ketone body production by the liver. The effect was not associated with an elevation in NAD+/NADH ratio according to our metabolomics analysis. The data provide a novel molecular mechanism for SB activity in the induction of ketone body production.

iSucc-PseAAC:Prediction of Lysine Succinylation Modification Sites Based on Ensemble Machine Learning / 中国生物化学与分子生物学报

Lysine succinylation is a novel post-translational modification, which plays an important role in regulating distinct cellular functions control, therefore it is necessary to accurately identify succinylation sites in proteins. As traditional experiments consume material and financial resources, prediction by calculation is an efficient method being proposed recently. In this study, we developed a new prediction method iSucc-PseAAC, which uses a variety of classification algorithms combined with different feature extraction methods. Moreover, it is found that under the feature extraction based on coupled sequence (PseAAC), the classification effect of support vector machine is the best, and it could be combined with ensemble learning to solve the problem of data imbalance. Compared with the existing methods, iSucc-PseAAC has more significance and practicality in predicting lysine succinylation sites.

Intra and Extra-granular Disintegrant Properties of Modified Underutilised Red Lima Bean Starch in Paracetamol Tablet Formulation

Abstract Red lima bean (Phaseolus lunatus Linn) Family Fabaceae, has been modified by succinylation and annealing, and used as intra- and extra-granular disintegrants at concentrations of 5 and 10 %w/w in paracetamol tablet formulation in comparison with corn starch BP. The starches were characterised using FT-IR spectroscopy, SEM, proximate analysis, physicochemical and functional properties. FT-IR spectrometry revealed characteristic peaks at 1575.53 and 1713.99 cm-1 for the succinylated starch while the annealed showed no significant difference from the native starch. Modifications did not alter the ovoid shape of the native starch but reduced the particle size. Succinylation improved water absorption capacity, solubility and swelling of lima bean starch but annealing reduced the parameters. Tablets with disintegrants of lima bean starches generally had higher crushing strengths and lower friability than tablets with corn starch. Modifications reduced the disintegration time of the tablets when the starches were incorporated intra-granularly, which suggested particle-particle bond interruption and destruction of hydrogen bonds as mechanism of disintegration. Tablets containing 10 %w/w succinylated red lima bean starch incorporated intra-granularly had the highest disintegration efficiency ratio, DER, indicating a great balance between mechanical and disintegration properties. Modified red lima bean starches incorporated intra-granularly into paracetamol tablets led to faster disintegration and could efficiently substitute corn starch as disintegrant.

High protein acetylation/succinylation levels and their correlation with high histone 2AX expression level in breast cancer / 解剖学报

Objective To explore the protein acetylation/succinylation and histone 2AX (H2AX) expression levels in breast cancer, as well as their correlation. Methods By Western blotting and RT-PCR methods to detect the protein modification and H2AX expression levels in 11 breast cancer tissues and cells, as well as to explore the common regulation way of protein acetylation and succinylation by treatment of histone deacetylase inhibitors ; To study the relationship between H2AX expression level and protein modification level through the construction and over-expression of indicated plasmids. Results Compared with the adjacent normal tissues, there existed an increase protein acetylation/succinylation levels in breast cancer tissues, and the protein acetylation and succinylation were both regulated by histone deacetylase (HDAC) members. The H2AX mRNA and protein expression levels were increased both in breast cancer cell and tissues, its expression level and the expression and modification level of represented protein nucleophosmin 1(NPM1) showed a positive correlation. Conclusion The breast cancer possesses a characteristic of high protein acetylation/succinylation levels and high H2AX expression level, the H2AX expression level and the modification level of partial proteins in breast cancer have a positive correlation.

NF- B/HDAC1/SREBP1c pathway mediates the inflammation signal in progression of hepatic steatosis

The transcription factor nuclear factor kappa B (NF-B) is activated in hepatocytes in the pathogenesis of hepatic steatosis. However, the action mechanism of NF-B remains to be established in the hepatic steatosis. In this study, the subunit of NF-B was found to promote the hepatic steatosis through regulation of histone deacetylase 1 (HDAC1) in hepatocytes. The activity was supported by the phenotypes of knockout (-KO) mice and knockout (-KO) mice. Hepatic steatosis was reduced in the -KO mice, but not in the -KO mice. The reduction was a result of inhibition of HDAC1 activity in the -KO cells. Knockdown of gene led to suppression of hepatocyte steatosis in HepG2 cells. A decrease in sterol-regulatory element binding protein 1c (SREBP1c) protein was observed in the liver of -KO mice and in cell with knockdown. The decrease was associated with an increase in succinylation of SREBP1c protein. The study suggests that stabilizes HDAC1 to support the SREBP1c activity in hepatic steatosis in the pathophysiological condition. Interruption of this novel pathway in the -KO, but not the -KO mice, may account for the difference in hepatic phenotypes in the two lines of transgenic mice.

The research progress of protein lysine succinylation / 医学研究生学报

Recently the lysine succinylation was discovered in vivo, and it was demonstrated to be widely involved in cell dif-ferentiation, cell metabolism and other important physiological activities.Lysine succinylation has become the forefront of life science research.Scientists have provided a lot of evidences that proteins in prokaryotes and eukaryotes are widely succinylated, without which the central metabolism and intermediary metabolism of many metabolic enzymes are disrupted.To better understand the importance of Succinylation in vivo, protein-succinyl modification of the current research and the latest developments are reviewed, which summarize succinylated protein lysine sites in the center of important physiological metabolic pathways, diseases and other pathological conditions.

Gramicidin-S: Structure–activity relationship.

The two side chain amino groups of the two L-ornithine residues in gramicidin-S seem to be important for the antibacterial activity of the molecule, since complete acetylation, formylation, carbamylation, deamination, trinitrophenylation, succinylation, maleylation of the antibiotic caused 90–95 % loss of the antibacterial activity of the antibiotic. However this modification leads to only 12–30% loss of the hemolytic activity. Monoacetyl- and monoformyl gramicidin-S with a free amino group retains nearly 50% of the antibacterial activity of the molecule. It seems, therefore, that the two amino groups contribute equally to the antibacterial activity of gramicidin-S.