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151.
Li S Tao L Jiao X Liu H Cao Y Lopez B Luan RH Christopher T Ma XL 《Apoptosis : an international journal on programmed cell death》2007,12(10):1795-1802
Whole body non-penetrating trauma causes myocardial infarction in humans and mechanical trauma (MT) results in cardiac dysfunction
in animals. Our recent study demonstrated that incubation of cardiomyocytes with plasma isolated from MT animals causes significant
cardiomyocyte apoptosis that can be blocked by neutralization of TNFα. The present study attempted to obtain direct in vivo
evidence to support that overproduction of TNFα plays a causative role in trauma-induced cardiomyocyte apoptosis. Non-lethal
MT caused significant TNFα overproduction (2.4-fold at 1.5 h after MT) and increased cardiomyocyte apoptosis (starting 3 h
and peaking 12 h after MT). Pharmacological inhibition of TNFα with etanercept or TNFα gene deletion reduced post-trauma myocyte
apoptosis (P < 0.01). Expression of iNOS and NADPH oxidase, overproduction of NO and
, and excessive protein nitration in the MT heart were all significantly reduced in etanercept-treated or TNFα−/− mice, suggesting that oxidative/nitrative stress may contribute to TNFα-initiated myocyte apoptosis in MT hearts. Additional
experiments demonstrated that inhibiting iNOS (1400W) or NADPH oxidase (apocynin), or scavenging peroxynitrite (FP15) significantly
reduced myocyte apoptosis in MT animals (P < 0.01). Collectively, these data demonstrated that non-lethal mechanical trauma caused significant TNFα production that
in turn stimulated myocardial apoptosis via oxidative/nitrative stress. 相似文献
152.
153.
Zhang Z Qun J Cao C Wang J Li W Wu Y Du L Zhao P Gong K 《Molecular biology reports》2012,39(4):4445-4454
Circulating endothelial progenitor cells (EPCs) have a critical role in endothelial maintenance and repair. Apolipoprotein
A-I mimetic peptide D-4F has been shown to posses anti-atherogenic properties via sequestration of oxidized phospholipids,
induction of remodeling of high density lipoprotein and promotion of cholesterol efflux from macrophage-derived foam cells.
In this study, we test the effects of D-4F on EPC biology. EPCs were isolated from the peripheral venous blood of healthy
male volunteers and characterized by 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine-labeled acetylated LDL uptake
and ulex europaeus agglutinin binding and flow cytometry. Cell proliferation, migration, adhesion, nitric oxide production
and endothelial nitric oxide synthase (eNOS) expression in the absence and presence of D-4F or simvastatin (as a positive
control), were assayed. We demonstrated that D-4F significantly enhanced EPC proliferation, migration and adhesion in a dose-dependent
manner compared with vehicle. However, all of the favorable effects of D-4F on EPCs were dramatically attenuated by preincubation
with NOS inhibitor L-NAME. Further, D-4F also increased nitric oxide production in culture supernatant and the levels of eNOS
expression and phosphorylation. The stimulatory effects of D-4F (10 μg/ml) on EPC biology were comparable to 0.5 μM simvastatin.
These results suggest that eNOS/NO pathway mediates the functional modulation of EPC biology in response to D-4F treatment
and support the notion that the beneficial role of D-4F on EPCs may be one of the important components of its anti-atherogenic
potential. 相似文献
154.
【目的】克隆红纹黄单胞菌α-氨基酸酯水解酶基因全序列,对序列进行生物信息学分析,并提高酶的热稳定性。【方法】利用多聚酶链式反应(PCR)克隆α-氨基酸酯水解酶基因全序列;应用生物信息学软件对获得的基因序列及编码的蛋白序列进行分析;通过同源建模,预测红纹黄单胞菌α-氨基酸酯水解酶的三维结构;通过定点突变替换氨基酸序列中高度柔性的位点,提高该酶的热稳定性。【结果】从红纹黄单胞菌(Xanthomonas rubrillineans)中扩增得到α-氨基酸酯水解酶基因aeh(GenBank登录号JF744990),核苷酸序列长度1 917 bp,编码638个氨基酸。序列比对和同源性分析显示,该酶与白纹黄单胞菌Xanthomonas albilineans str.GPE PC73的肽酶及地毯草黄单胞菌Xanthomonas axono-podis pv. citri str. 306的戊二酰-7-氨基头孢烷酸酰化酶氨基酸序列相似性最高,分别为91%和83%,系统进化分析表明,该酶与白纹黄单胞菌Xanthomonas albilineans str. GPEPC73的肽酶亲缘性最高。基于预测的三维模型,对高度柔性的位点进行饱和突变,从282株突变体中筛选得到3株T50较野生型高5°C以上的突变体。【结论】对红纹黄单胞菌AEH的氨基酸序列分析有助于探索同源蛋白的进化过程。对高度柔性位点进行饱和突变的策略可以用于提高热稳定性。 相似文献
155.
Cao P Sun W Kramp K Zheng M Salom D Jastrzebska B Jin H Palczewski K Feng Z 《FASEB journal》2012,26(2):480-491
Activation of G-protein-coupled receptors (GPCRs) initiates signal transduction cascades that affect many physiological responses. The worm Caenorhabditis elegans expresses >1000 of these receptors along with their cognate heterotrimeric G proteins. Here, we report properties of 9-cis-retinal regenerated bovine opsin [(b)isoRho] and human melanopsin [(h)Mo], two light-activated, heterologously expressed GPCRs in the nervous system of C. elegans with various genetically engineered alterations. Profound transient photoactivation of G(i/o) signaling by (b)isoRho led to a sudden and transient loss of worm motility dependent on cyclic adenosine monophosphate, whereas transient photoactivation of G(q) signaling by (h)Mo enhanced worm locomotion dependent on phospholipase Cβ. These transgenic C. elegans models provide a unique way to study the consequences of G(i/o) and G(q) signaling in vivo with temporal and spatial precision and, by analogy, their relationship to human neuromotor function. 相似文献
156.
157.
Chen ZY Zeng DY Hu YT He YW Pan N Ding JP Cao ZJ Liu ML Li WX Yi H Jiang L Wu YL 《PloS one》2012,7(4):e35154
Background
Although the basic scorpion K+ channel toxins (KTxs) are well-known pharmacological tools and potential drug candidates, characterization the acidic KTxs still has the great significance for their potential selectivity towards different K+ channel subtypes. Unfortunately, research on the acidic KTxs has been ignored for several years and progressed slowly.Principal Findings
Here, we describe the identification of nine new acidic KTxs by cDNA cloning and bioinformatic analyses. Seven of these toxins belong to three new α-KTx subfamilies (α-KTx28, α-KTx29, and α-KTx30), and two are new members of the known κ-KTx2 subfamily. ImKTx104 containing three disulfide bridges, the first member of the α-KTx28 subfamily, has a low sequence homology with other known KTxs, and its NMR structure suggests ImKTx104 adopts a modified cystine-stabilized α-helix-loop-β-sheet (CS-α/β) fold motif that has no apparent α-helixs and β-sheets, but still stabilized by three disulfide bridges. These newly described acidic KTxs exhibit differential pharmacological effects on potassium channels. Acidic scorpion toxin ImKTx104 was the first peptide inhibitor found to affect KCNQ1 channel, which is insensitive to the basic KTxs and is strongly associated with human cardiac abnormalities. ImKTx104 selectively inhibited KCNQ1 channel with a Kd of 11.69 µM, but was less effective against the basic KTxs-sensitive potassium channels. In addition to the ImKTx104 toxin, HeTx204 peptide, containing a cystine-stabilized α-helix-loop-helix (CS-α/α) fold scaffold motif, blocked both Kv1.3 and KCNQ1 channels. StKTx23 toxin, with a cystine-stabilized α-helix-loop-β-sheet (CS-α/β) fold motif, could inhibit Kv1.3 channel, but not the KCNQ1 channel.Conclusions/Significance
These findings characterize the structural and functional diversity of acidic KTxs, and could accelerate the development and clinical use of acidic KTxs as pharmacological tools and potential drugs. 相似文献158.
金黄色葡萄球菌是导致医院院内感染的主要病原。由于金黄色葡萄球菌极易产生抗药性,因此疫苗免疫是预防该细菌感染的主要手段。作为一个粘附分子,凝集因子B(ClfB)的作用是使金黄色葡萄球菌能够在宿主黏膜定植,是预防该菌感染的一个重要的靶分子。本研究成功地在大肠杆菌中表达了可溶的ClfB N1-N3结构域蛋白(Truncated-ClfB),并且利用亲和层析、离子交换层析和凝胶过滤技术对其进行了纯化。用纯化后的Truncated-ClfB免疫新西兰大白兔,收集三免后的血清检测其抗体水平并且利用流式细胞术检测抗血清的调理吞噬活性。检测结果表明,三免后的兔源Truncated-ClfB抗血清抗体效价高达1:640 000;与免疫前兔源血清相比,兔源Truncated-ClfB抗血清能够显著增加多形核白细胞(Polymorphonuclear leukocytes,PMN)对金黄色葡萄球菌的吞噬效率(P0.01)。结果表明Truncated-Clf B有希望作为金黄色葡萄球菌疫苗的候选抗原。 相似文献
159.
160.