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Among the iron-sulfur cluster assembly proteins encoded by gene cluster iscSUA-hscBA-fdx in Escherichia coli, IscA has a unique and strong iron binding activity and can provide iron for iron-sulfur cluster assembly in proteins in vitro. Deletion of IscA and its paralogue SufA results in an E. coli mutant that fails to assemble [4Fe-4S] clusters in proteins under aerobic conditions, suggesting that IscA has a crucial role for iron-sulfur cluster biogenesis. Here we report that among the iron-sulfur cluster assembly proteins, IscA also has a strong and specific binding activity for Cu(I) in vivo and in vitro. The Cu(I) center in IscA is stable and resistant to oxidation under aerobic conditions. Mutation of the conserved cysteine residues that are essential for the iron binding in IscA abolishes the copper binding activity, indicating that copper and iron may share the same binding site in the protein. Additional studies reveal that copper can compete with iron for the metal binding site in IscA and effectively inhibits the IscA-mediated [4Fe-4S] cluster assembly in E. coli cells. The results suggest that copper may not only attack the [4Fe-4S] clusters in dehydratases, but also block the [4Fe-4S] cluster assembly in proteins by targeting IscA in cells.

Green tea (Camellia sinensis, Cs) abundantly produces a diverse array of phenylpropanoid compounds benefiting human health. To date, the regulation of the phenylpropanoid biosynthesis in tea remains to be investigated. Here, we report a cDNA isolated from leaf tissues, which encodes a R2R3-MYB transcription factor. Amino acid sequence alignment and phylogenetic analysis indicate that it is a member of the MYB4-subgroup and named as CsMYB4a. Transcriptional and metabolic analyses show that the expression profile of CsMYB4a is negatively correlated to the accumulation of six flavan-3-ols and other phenolic acids. GFP fusion analysis shows CsMYB4a’s localization in the nucleus. Promoters of five tea phenylpropanoid pathway genes are isolated and characterized to contain four types of AC-elements, which are targets of MYB4 members. Interaction of CsMYB4a and five promoters shows that CsMYB4a decreases all five promoters’ activity. To further characterize its function, CsMYB4a is overexpressed in tobacco plants. The resulting transgenic plants show dwarf, shrinking and yellowish leaf, and early senescence phenotypes. A further genome-wide transcriptomic analysis reveals that the expression levels of 20 tobacco genes involved in the shikimate and the phenylpropanoid pathways are significantly downregulated in transgenic tobacco plants. UPLC-MS and HPLC based metabolic profiling reveals significant reduction of total lignin content, rutin, chlorogenic acid, and phenylalanine in CsMYB4a transgenic tobacco plants. Promoter sequence analysis of the 20 tobacco genes characterizes four types of AC-elements. Further CsMYB4a-AC element and CsMYB4a-promoter interaction analyses indicate that the negative regulation of CsMYB4a on the shikimate and phenylpropanoid pathways in tobacco is via reducing promoter activity. Taken together, all data indicate that CsMYB4a negatively regulates the phenylpropanoid and shikimate pathways.Highlight: A tea (Camellia sinensis) MYB4a is characterized to encode a R2R3-MYB transcription factor. It is shown to repressively control the phenylpropanoid and shikimate pathway.

Aim: To determine the cardioprotective action of ghrelin and des-octanoyl ghrelin in rats with isoproterenol-induced myocardial injury. Methods: Rats were subcutaneously injected with isoproterenol (ISO; 20, 10, and 5 mg/kg) on d 1, 2 and 3, respectively, and then 3 mg/kg for the next 7 d with or without ghrelin or desoctanoyl-ghrelin (100 µg/kg, twice daily). Plasma ghrelin and growth hormone levels were assayed using radioimmunoassay methods. Growth hormone secretagogue receptor (GHSR) and ghrelin mRNA were determined using RT-PCR. The maximal binding capacity and the affinity for [ 3 H]ghrelin were determined by receptor binding assays. Results: Compared with controls, ISO-treated rats showed severe myocardial injury, cardiomegaly, infarction-like necrosis and massive fibrosis with increases in irradiated-ghrelin (ir-ghrelin) content in plasma by 67% and myocardia by 66% and in the mRNA level in the myocardia by 93% (P<0.01). ISO-treated rats had 95% (P<0.01) higher GHSR mRNA levels in the myocardia. The maximal binding capacity of [ 3 H]ghrelin for myocardial sarcolemma was higher in ISO-treated rats than in controls. Ghrelin administration improved cardiac function and ameliorated cardiomegaly and attenuated myocardial lipid peroxidation injury and relieved cardiac fibrosis as compared with ISO treatment alone. Administration of des-octanoyl ghrelin effectively antagonized ISO-induced myocardial injury and improved all parameters measured. However, the therapeutic effect of des-octanoyl ghrelin was significantly weaker than that of ghrelin. The plasma growth hormone level increased markedly, by 1.5-fold (P<0.01), with ghrelin administration as compared with that in controls, but was unaltered in the desoctanoyl ghrelin group. Conclusion: Myocardial ghrelin and GHSR were upregulated during ISO-induced myocardial injury. The protective effect of ghrelin against ISO-induced cardiac function injury and fibrosis was more potent than that of des-octanoyl ghrelin, which suggests that ghrelin could be an endogenous cardioprotective factor in ischemic heart disease, and that its effects include growth hormone-dependent and -independent pathways.

esistin was first found in 2001 by Steppan and coworkers as a novel peptide synthesized and secreted from murine adipocytes. 1 Circulating resistin level was increased in diet-induced and genetic forms of obesity but could be decreased using rosiglitazone therapy. Administration of anti-resistin antibodies improved blood glucose control and insulin action in mice with dietinduced obesity. 1 Resistin is thought to be an adipokine associated with insulin resistance.Subsequent studies of its role in human obesity and insulin resistance, however, showed conflicting results. 2 Contrary to the distribution in rodents, in humans, the main sources of resistin seem to be monocytes and macrophages. 3 Resistin level was positively associated with levels of inflammatory markers, including soluble tumor necrosis factor-receptor-2, interleukin-6 and lipoprotein-associated phospholipase A2. 4 Moreover, resistin up-regulates the expression of adhesion molecules in cultured endothelial cells and promotes the proliferation of smooth muscle cells, which suggests that it may be an inflammatory marker. 4 inflammation and atherosclerosis. 7,8 Indeed, resistin levels were also correlated with high-sensitivity C-reactive protein (hs-CRP) level, insulin level and homeostasis model assessment of insulin resistance. In a study adjusting for age, sex and established risk factors, the concentration of resistin was also associated with increasing coronary artery calcification (CAC); resistin levels further predicted CAC in subjects with metabolic syndrome. 4 Also, Ohmori reported resistin levels increased in 157 patients with coronary artery disease, even after adjusting for age and gender. Resistin levels were found to increase stepwise, depending on number of stenotic vessels and/or segments. 7 Acute coronary syndrome (ACS) is an acute cardiac event resulting from rupture of vulnerable atherosclerotic plaque in the coronary artery. In ACS, a large amount of inflammatory cells and cytokines are released to the circulation and accelerate the development of atherosclerosis, which results from chronic metabolic abnormality. In the present study, we observed plasma resistin level in patients with ACS during the first week after symptom onset, analyzed the relation of plasma resistin level and clinical index, and investigated the potential significance of resistin in ACS pathogenesis. Method SubjectsThe study was reviewed and approved by the Ethics Committee of Peking University First Hospital, and informed consent was obtained from each subject before the study began. The aim of the present study was to investigate the alteration in level of plasma resistin in patients with acute coronary syndrome (ACS) to uncover the role of resistin. Methods and ResultsThe 39 patients with ACS and 26 age-matched healthy subjects in this cross-sectional study were investigated. Plasma resistin levels were measured using radioimmunoassay. Plasma resistin levels were significantly increased in patients with ACS at 24 h after symptoms onset and remained at a high...

Increasing evidence suggests that the gut microbiota plays vital roles in metabolic diseases. Polygonatum odoratum extract alleviates hyperglycemia and hyperlipidemia, but the underlying mechanism remains unclear. This study investigated the effects of P. odoratum polysaccharides (POPs) on high-fat diet (HFD)-induced obesity in rats and whether these effects were related to modulation of gut microbiota. POP treatment attenuated weight gain, fat accumulation, epididymal adipocyte size, liver triglycerides, and total liver cholesterol content in HFD-fed rats. POP administration also increased short-chain fatty acids (SCFAs), including isobutyric acid, butyric acid, and valeric acid. POP upregulated the expression of genes involved in adipocyte differentiation (Pparg, Cebpa, Cebpb) and lipolysis (Ppara, Atgl), and downregulated those related to lipid synthesis (Srebpf1, Fabp4, Fas), with corresponding changes in PPARγ and FABP4 protein expression. Finally, POP enhanced species richness and improved the gut microbiota community structure, reducing the relative abundances of Clostridium, Enterococcus, Coprobacillus, Lactococcus, and Sutterella. Principal coordinates analysis (PCoA) revealed a clear separation between HFD-fed rats and all other treatment groups. Correlation analysis identified negative and positive associations between obesity phenotypes and 28 POP-influenced operational taxonomic units (OTUs), including putative SCFA-producing bacteria. Our data suggest that POP supplementation may attenuate features of obesity in HFD-fed rats in association with the modulation of gut microbiota.

Aim: To investigate the role of the endogenous cystathionine γ-synthase (CSE)/ hydrogen sulfide (H 2 S) pathway in vascular calcification in vivo. Methods: A rat vascular calcification model was established by administration of vitamin D3 plus nicotine (VDN). The amount of CSE and osteopontin (OPN) mRNA was determined by using semi-quantitative reverse-transcription polymerase chain reaction. The calcium content, 45 Ca2+ accumulation and alkaline phosphatase (ALP) activity were measured. H 2 S production and CSE activity were measured. Results: von Kossa staining produced strong positive black/brown staining in areas among the elastic fibers of the medial layer in the calcified aorta. The calcium content, 45 Ca 2+ accumulation and ALP activity in calcified arteries increased by 6.77-, 1.42-, and 1.87-fold, respectively, compared with controls. The expression of the OPN gene was upregulated (P<0.01). Expression of the CSE gene was downregulated. However, calcium content, 45 Ca2+ uptake and ALP activity in the VDN plus NaHS group was lower than that in the VDN group. The content of calcium and 45 Ca 2+ accumulation and activity of ALP in the aorta were 34.8%, 40.75% and 63.5% lower in the low-dosage NaHS group than in the VDN group, respectively (P<0.01), and the calcium content and deposition of 45 Ca2+ and activity of ALP was 83.9%, 37.8 % and 46.2% lower in the aorta in the high-dosage NaHS group than in the VDN group, respectively (P<0.01). The expression of the OPN gene was downregulated. Conclusion: The production of H 2 S, and CSE activity were decreased and CSE gene expression was downregulated in rats with vascular calcification. H 2 S can ameliorate vascular calcification, suggesting that the H 2 S/ CSE pathway plays a regulatory role in the pathogenesis of vascular calcification.