THE ROLE OF ANGIOTENSINOGEN IN ATHEROSCLEROSIS AND OBESITY

Angiotensinogen is the only known precursor in the renin-angiotensin system, a hormonal system best known as an essential regulator of blood pressure and fluid homeostasis. Angiotensinogen is sequentially cleaved by renin and angiotensin- converting enzyme to generate angiotensin II. As the major effector peptide, angiotensin II mainly function through angiotensin type 1 receptor. Angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and more recently renin inhibitors are widely known as the 3 classic renin-angiotensin system inhibitory drugs against hypertension and atherosclerosis. Here, we developed an array of regents to explore the effects of angiotensinogen inhibition. First, we demonstrated that genetic deficiency of angiotensinogen not only protected against hypercholesterolemia- induced atherosclerosis but also prevented diet-induced obesity. Then we found weekly intraperitoneal injection of antisense oligonucleotides against angiotensinogen remarkably surpressed body weight gain in mice fed a western diet, which was absent from classic renin-angiotensin system inhibition. The suppressed body weight gain was attributable to diminished body fat mass gain and enhanced energy expenditure. More excitingly, angiotensinogen antisense oligonucleotides regressed body weight gain on obese mice. Together, our findings revealed a unique feature of angiotensinogen inhibition beyond classic renin angiotensin inhibition and demonstrated therapeutic potentials of angiotensinogen antisense oligonucleotides against hypertension, atherosclerosis, and obesity. We also developed an in vivo system to explore the functional consequences of disrupting a conserved Cys18-Cys137 disulfide bridge in angiotensinogen. The formation of this disulfide bridge could trigger conformational changes in angiotensinogen, thereby facilitating renin cleavage of angiotensinogen. It was predicted that the redox-sensitive disulfide bridge might change the efficiency of angiotensinogen/renin reaction to release angiotensin II, thus modulate angiotensin II-dependent functions. We determined effects of the presence and absence of the disulfide bridge on angiotensin II concentrations and responses in mice expressing either native angiotensinogen or Cys18Ser, Cys137Ser mutated angiotensinogen in liver via adeno-associated viral vectors. Contrary to the prediction, disruption of Cys18-Cys137 disulfide bridge in angiotensinogen had no discernible effects on angiotensin II production and angiotensin II-dependent functions in mice

One Amino Acid Change of Angiotensin II Diminishes Its Effects on Abdominal Aortic Aneurysm

Angiotensin (Ang) A is formed by the decarboxylation of the N terminal residue of AngII. The present study determined whether this one amino acid change impacted effects of AngII on abdominal aortic aneurysm (AAA) formation in mice. Computational analyses implicated that AngA had comparable binding affinity to both AngII type 1 and 2 receptors as AngII. To compare effects of these two octapeptides in vivo, male low-density lipoprotein receptor (Ldlr) or apolipoprotein E (Apoe) deficient mice were infused with either AngII or AngA (1 μg/kg/min) for 4 weeks. While AngII infusion induced AAA consistently in both mouse strains, the equivalent infusion rate of AngA did not lead to AAA formation. We also determined whether co-infusion of AngA would influence AngII-induced aortic aneurysm formation in male Apoe−/− mice. Co-infusion of the same infusion rate of AngII and AngA did not change AngII-induced AAA formation. Since it was reported that a 10-fold higher concentration of AngA elicited comparable vasoconstrictive responses as AngII, we compared a 10-fold higher rate (10 μg/kg/min) of AngA infusion into male Apoe−/− mice with AngII (1 μg/kg/min). This rate of AngA led to abdominal aortic dilation in three of ten mice, but no aortic rupture, whereas the 10-fold lower rate of AngII infusion led to abdominal aortic dilation or rupture in eight of ten mice. In conclusion, AngA, despite only being one amino acid different from AngII, has diminished effects on aortic aneurysmal formation, implicating that the first amino acid of AngII has important pathophysiological functions

Five-Membered Cyclic Metal Carbyne: Synthesis of Osmapentalynes by the Reactions of Osmapentalene with Allene, Alkyne, and Alkene

通讯作者地址: Zhu, JThe synthesis of small cyclic metal carbynes is challenging due to the large angle strain associated with the highly distorted nonlinear triple bonds. Herein, we report a general route for the synthesis of five-membered cyclic metal carbyne complexes, osmapentalynes, by the reactions of an osmapentalene derivative with allene, alkyne, and alkene. Experimental observations and theoretical calculations document the aromaticity in the fused five-membered rings of osmapentalynes. The realization of transforming osmapentalene to osmapentalyne through this general route would not only allow further exploration of metallapentalyne chemistry but also show promising applications of this novel aromatic system with broad absorption band and high molar absorption coefficient.973 Program 2012CB821600 NSFC 21332002 21174115 21172184 Program for New Century Excellent Talents in University NCET-13-0511 program for Changjiang Scholars and Innovative Research Team in Universit

Planar Möbius aromatic pentalenes incorporating 16 and 18 valence electron osmiums

夏海平课题组长期致力于芳香体系的拓展研究。作为金属杂戊搭炔化学又一重要进展，在此研究中，他们发现金属杂戊搭炔的卡拜碳原子宛如“变色龙”，既具有亲核性，又具有亲电性。通过金属杂戊搭炔与亲电试剂反应揭示了其三键迁移的神秘面纱，并成功地捕捉了三键迁移的中间体——金属中心为16电子的金属杂戊搭烯；通过金属杂戊搭炔与亲核试剂反应，得到金属中心为18电子的金属杂戊搭烯。 　　朱军课题组通过理论计算，对金属杂戊搭烯进行深入理论研究。发现金属中心16电子、18电子金属杂戊搭烯均具有芳香性。深入的CMO-NICS计算表明，本质上，金属杂戊搭炔中Mobius芳香性来源于金属杂戊搭烯，正如苯炔的芳香性来源于苯。Mobius芳香性自1958年提出以来，实际合成的例子稀少，且前人已分离并报道的Möbius芳香体系均具有扭曲的拓扑结构。金属杂戊搭烯/炔代表着一类平面型的Möbius芳香性体系。从而颠覆了传统的芳香化学，为构筑其他平面型Möbius芳香体系奠定了基础。 　　该工作的合成和结构表征是在夏海平教授指导下由博士生朱从青（第一作者）、罗明和硕士生朱琴完成，我校温庭斌教授参与了产物结构表征的讨论。理论计算由朱军副教授完成，我校吕鑫教授、美国佐治亚大学P.v.R.Schleyer教授和J.I-C.Wu博士也参与了芳香性的讨论。Aromaticity, a highly stabilizing feature of molecules with delocalized electrons in closed circuits, is generally restricted to ‘Hückel’ systems with 4n+2 mobile electrons. Although the Möbius concept extends the principle of aromaticity to 4n mobile electron species, the rare known examples have complex, twisted topologies whose extension is unlikely. Here we report the realization of osmapentalenes, the first planar Möbius aromatic complexes with 16 and 18 valence electron transition metals. The Möbius aromaticity of these osmapentalenes, documented by X-ray structural, magnetic and theoretical analyses, demonstrates the basis of the aromaticity of the parent osmapentalynes. All these osmapentalenes are formed by both electrophilic and nucleophilic reactions of the in-plane π component of the same carbyne carbon, illustrating ambiphilic carbyne reactivity, which is seldom observed in transition metal chemistry. Our results widen the scope of Möbius aromaticity dramatically and open prospects for the generalization of planar Möbius aromatic chemistry.国家自然科学基金委、科技部和美国科学基金会的资

Chaotic Vibration Prediction of a Free-Floating Flexible Redundant Space Manipulator

The dynamic model of a planar free-floating flexible redundant space manipulator with three joints is derived by the assumed modes method, Lagrange principle, and momentum conservation. According to minimal joint torque’s optimization (MJTO), the state equations of the dynamic model for the free-floating redundant space manipulator are described. The PD control using the tracking position error and velocity error in the manipulator is introduced. Then, the chaotic dynamic behavior of the manipulator is analyzed by chaotic numerical methods, in which time series, phase plane portrait, Poincaré map, and Lyapunov exponents are used to analyze the chaotic behavior of the manipulator. Under certain conditions for the joint torque optimization and initial values, chaotic vibration motion of the space manipulator can be observed. The chaotic time series prediction scheme for the space manipulator is presented based on the theory of phase space reconstruction under Takens’ embedding theorem. The trajectories of phase space can be reconstructed in embedding space, which are equivalent to the original space manipulator in dynamics. The one-step prediction model for the chaotic time series and the chaotic vibration was established by using support vector regression (SVR) prediction model with RBF kernel function. It has been proved that the SVR prediction model has a good performance of prediction. The experimental results show the effectiveness of the presented method

Differential Proteomics Analysis of Colonic Tissues in Patients of Slow Transit Constipation

Objective. To investigate and screen the different expression of proteins in STC and normal group with a comparative proteomic approach. Methods. Two-dimensional electrophoresis was applied to separate the proteins in specimens from both 5 STC patients and 5 normal controls. The proteins with statistically significant differential expression between two groups were identified by computer aided image analysis and matrix assisted laser desorption ionization tandem time of flight mass spectrometry (MALDI-TOF-MS). Results. A total of 239 protein spots were identified in the average gel of the normal control and 215 in patients with STC. A total of 197 protein spots were matched and the mean matching rate was 82%. There were 14 protein spots which were expressed with statistically significant differences from others. Of those 14 protein spots, the expression of 12 spots increased markedly, while that of 2 spots decreased significantly. Conclusion. The proteomics expression in colonic specimens of STC patients is statistically significantly different from that of normal control, which may be associated with the pathogenesis of STC

Antisense oligonucleotides targeting hepatic angiotensinogen reduce atherosclerosis and liver steatosis in hypercholesterolemic mice

Hepatocyte-derived angiotensinogen (AGT) is the precursor of angiotensin II (AngII). We determined the effects of hepatocyte-specific (N-acetylgalactosamine-conjugated) antisense oligonucleotides targeting AGT (GalNAc AGT ASO) on AngII-mediated blood pressure (BP) regulation and atherosclerosis and compared its effects with losartan, an AngII type 1 (AT1) receptor blocker, in hypercholesterolemic mice. Eight-week-old male low-density lipoprotein (LDL) receptor deficient mice were administered vehicle or GalNAc AGT ASO (1, 2.5, or 5 mg/kg) subcutaneously beginning 2 weeks before the initiation of Western diet feeding. All mice were fed Western diet for 12 weeks. Their systolic BP was monitored by the tail-cuff technique, and the atherosclerotic lesion area was measured by an en face method. Although the effects of all 3 doses of GalNAc AGT ASO on plasma AGT concentrations were similar, GalNAc AGT ASO reduced BP and atherosclerotic lesion size in a dose-dependent manner. Subsequently, we compared the effects of GalNAc AGT ASO (5 mg/kg) with losartan (15 mg/kg/day). Compared to losartan, GalNAc AGT ASO led to more profound increases in plasma renin and reduction in BP but had similar effects on atherosclerosis. Remarkably, GalNAc AGT ASO also reduced liver steatosis, which was not observed in losartan-treated mice. In conclusion, the BP increase and atherosclerosis development in hypercholesterolemic mice are dependent on AngII generated from hepatic AGT. Deleting hepatic AGT improves diet-induced liver steatosis, and this occurs in an AT1 receptor-independent manner.</p

Synthesis, Characterization, and Electrochemical Properties of Bisosmabenzenes Bridged by Diisocyanides

Treatment of osmabenzene [Os(CHC(PPh3)CHC(PPh3)CH)Cl-2(PPh3)(2)]OH (3) with various diisocyanides in the presence of NH4PF6 afforded a series of diisocyanide-bridged bisosmabenzenes [(mu-CN-R-NC){Os(CHC(PPh3)CHC(PPh3)CH)Cl-2(PPh3)}(2)][PF6](2) (R = 4,4'-C6H4-C6H4 (5a), 4,4'-C6H4CH2C6H4 (5b), 4,4'-C6H4OC6H4 (5c), 1,4-C6H4 (5d)) in good yields through ligand substitution reactions. Similarly, reaction of osmafuran [Os(CHC(PPh3)C(OEt)O)Cl-2(PPh3)(2)] (6) with 1,4-phenylenediisocyanide produced the diisocynide-bridged bisosmafuran [mu-(1,4-phenylenediisocyanide){Os(CHC(PPh3)C(OEt)O)Cl(PPh3)(2)}(2))Cl-2 (7). Bisosmabenzenes containing a chloro and a phosphonium substituent on each metallacycle [(mu-CN-R-NC){Os(CHC(PPh3)CHCCICH)Cl(PPh3)(2)}(2)]Cl-2 (R = 4,4'-C6H4-C6H4 (9a), 4,4'-C6H4CH2C6H4 (9b), 4,4'-C6H4OC6H4 (9c), 1,4-C6H4 (9d)) could be obtained in modest yields from the reactions of the osmacycle [Os(CH=C(PPh3)CH(OH)-eta(2)-C CH)Cl-2(PPh3)(2)] (8) with corresponding diisocyanides in the presence of NH4PF6 and NaCl via nucleophilic addition reactions. All of these complexes have been fully characterized by H-1, P-31{H-1}, and C-13{H-1} NMR spectrometry, IR spectrometry, and elemental analyses. Moreover, the structure of 9d has been established by X-ray crystallography. The electrochemical properties of stable bisosmabenzenes 9a-d have been investigated, which revealed that the two metal centers in 9c and 9d can interact with each other through a diisocyanide bridge.National Science Foundation of China [20925208, 20872123, 20772100]; Program for New Century Excellent Talents in University of China [NCET-08-0471]; Program for New Century Excellent Talents in Fujian Province University ; Department of Science & Technology of Fujian Province [2007F3095

Angiotensinogen Suppression: A New Tool to Treat Cardiovascular and Renal Disease

Multiple types of renin-angiotensin system (RAS) blockers exist, allowing interference with the system at the level of renin, angiotensin-converting enzyme, or the angiotensin II receptor. Yet, in particular, for the treatment of hypertension, the number of patients with uncontrolled hypertension continues to rise, either due to patient noncompliance or because of the significant renin rises that may, at least partially, overcome the effect of RAS blockade (RAS escape). New approaches to target the RAS are either direct antisense oligonucleotides that inhibit angiotensinogen RNA translation, or small interfering RNA (siRNA) that function via the RNA interference pathway. Since all angiotensins stem from angiotensinogen, lowering angiotensinogen has the potential to circumvent the RAS escape phenomenon. Moreover, antisense oligonucleotides and small interfering RNA require injections only every few weeks to months, which might reduce noncompliance. Of course, angiotensinogen suppression also poses a threat in situations where the RAS is acutely needed, for instance in women becoming pregnant during treatment, or in cases of emergency, when severe hypotension occurs. This review discusses all preclinical data on angiotensinogen suppression, as well as the limited clinical data that are currently available. It concludes that it is an exciting new tool to target the RAS with high specificity and a low side effect profile. Its long-term action might revolutionize pharmacotherapy, as it could overcome compliance problems. Preclinical and clinical programs are now carefully investigating its efficacy and safety profile, allowing an optimal introduction as a novel drug to treat cardiovascular and renal diseases in due time

Extracellular Histones Trigger Disseminated Intravascular Coagulation by Lytic Cell Death

Histones are cationic nuclear proteins that are essential for the structure and functions of eukaryotic chromatin. However, extracellular histones trigger inflammatory responses and contribute to death in sepsis by unknown mechanisms. We recently reported that inflammasome activation and pyroptosis trigger coagulation activation through a tissue-factor (TF)-dependent mechanism. We used a combination of various deficient mice to elucidate the molecular mechanism of histone-induced coagulation. We showed that histones trigger coagulation activation in vivo, as evidenced by coagulation parameters and fibrin deposition in tissues. However, histone-induced coagulopathy was neither dependent on intracellular inflammasome pathways involving caspase 1/11 and gasdermin D (GSDMD), nor on cell surface receptor TLR2- and TLR4-mediated host immune response, as the deficiency of these genes in mice did not protect against histone-induced coagulopathy. The incubation of histones with macrophages induced lytic cell death and phosphatidylserine (PS) exposure, which is required for TF activity, a key initiator of coagulation. The neutralization of TF diminished the histone-induced coagulation. Our findings revealed lytic cell death as a novel mechanism of histone-induced coagulation activation and thrombosis