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1.
Zbigniew Zawada Martin Šafařík Eva Dvořáková Olga Janoušková Anna Březinová Ivan Stibor Karel Holada Petr Bouř Jan Hlaváček Jaroslav Šebestík 《Amino acids》2013,44(5):1279-1292
Quinacrine is a drug that is known to heal neuronal cell culture infected with prions, which are the causative agents of neurodegenerative diseases called transmissible spongiform encephalopathies. However, the drug fails when it is applied in vivo. In this work, we analyzed the reason for this failure. The drug was suggested to “covalently” modify the prion protein via an acridinyl exchange reaction. To investigate this hypothesis more closely, the acridine moiety of quinacrine was covalently attached to the thiol groups of cysteines belonging to prion-derived peptides and to the full-length prion protein. The labeled compounds were conveniently monitored by fluorescence and absorption spectroscopy in the ultraviolet and visible spectral regions. The acridine moiety demonstrated characteristic UV–vis spectrum, depending on the substituent at the C-9 position of the acridine ring. These results confirm that quinacrine almost exclusively reacts with the thiol groups present in proteins and peptides. The chemical reaction alters the prion properties and increases the concentration of the acridine moiety in the prion protein. 相似文献
2.
Kyrill S. Rogacev Gunnar H. Heine Günther Silbernagel Marcus E. Kleber Sarah Seiler Insa Emrich Simone Lennartz Christian Werner Adam M. Zawada Danilo Fliser Michael B?hm Winfried M?rz Hubert Scharnagl Ulrich Laufs 《PloS one》2016,11(1)
Background
Impaired renal function causes dyslipidemia that contributes to elevated cardiovascular risk in patients with chronic kidney disease (CKD). The proprotein convertase subtilisin/kexin type 9 (PCSK9) is a regulator of the LDL receptor and plasma cholesterol concentrations. Its relationship to kidney function and cardiovascular events in patients with reduced glomerular filtration rate (GFR) has not been explored.Methods
Lipid parameters including PCSK9 were measured in two independent cohorts. CARE FOR HOMe (Cardiovascular and Renal Outcome in CKD 2–4 Patients—The Forth Homburg evaluation) enrolled 443 patients with reduced GFR (between 90 and 15 ml/min/1.73 m2) referred for nephrological care that were prospectively followed for the occurrence of a composite cardiovascular endpoint. As a replication cohort, PCSK9 was quantitated in 1450 patients with GFR between 90 and 15 ml/min/1.73 m2 enrolled in the Ludwigshafen Risk and Cardiovascular Health Study (LURIC) that were prospectively followed for cardiovascular deaths.Results
PCSK9 concentrations did not correlate with baseline GFR (CARE FOR HOMe: r = -0.034; p = 0.479; LURIC: r = -0.017; p = 0.512). 91 patients in CARE FOR HOMe and 335 patients in LURIC reached an endpoint during a median follow-up of 3.0 [1.8–4.1] years and 10.0 [7.3–10.6] years, respectively. Kaplan-Meier analyses showed that PCSK9 concentrations did not predict cardiovascular events in either cohort [CARE FOR HOMe (p = 0.622); LURIC (p = 0.729)]. Sensitivity analyses according to statin intake yielded similar results.Conclusion
In two well characterized independent cohort studies, PCSK9 plasma levels did not correlate with kidney function. Furthermore, PCSK9 plasma concentrations were not associated with cardiovascular events in patients with reduced renal function. 相似文献3.
Tom N Grammatopoulos Susan M Jones Ferogh A Ahmadi Brian R Hoover Lawrence D Snell Jesse Skoch Vimal V Jhaveri Andy M Poczobutt James A Weyhenmeyer W Michael Zawada 《Molecular neurodegeneration》2007,2(1):1-17
Background
Recent attention has focused on understanding the role of the brain-renin-angiotensin-system (RAS) in stroke and neurodegenerative diseases. Direct evidence of a role for the brain-RAS in Parkinson's disease (PD) comes from studies demonstrating the neuroprotective effect of RAS inhibitors in several neurotoxin based PD models. In this study, we show that an antagonist of the angiotensin II (Ang II) type 1 (AT1) receptor, losartan, protects dopaminergic (DA) neurons against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) toxicity both in primary ventral mesencephalic (VM) cultures as well as in the substantia nigra pars compacta (SNpc) of C57BL/6 mice (Fig. 1).Results
In the presence of exogenous Ang II, losartan reduced MPP+ (5 μM) induced DA neuronal loss by 72% in vitro. Mice challenged with MPTP showed a 62% reduction in the number of DA neurons in the SNpc and a 71% decrease in tyrosine hydroxylase (TH) immunostaining of the striatum, whereas daily treatment with losartan lessened MPTP-induced loss of DA neurons to 25% and reduced the decrease in striatal TH+ immunostaining to 34% of control.Conclusion
Our study demonstrates that the brain-RAS plays an important neuroprotective role in the MPTP model of PD and points to AT1 receptor as a potential novel target for neuroprotection. 相似文献4.
The pesticide rotenone induces caspase-3-mediated apoptosis in ventral mesencephalic dopaminergic neurons 总被引:6,自引:0,他引:6
Ahmadi FA Linseman DA Grammatopoulos TN Jones SM Bouchard RJ Freed CR Heidenreich KA Zawada WM 《Journal of neurochemistry》2003,87(4):914-921
In vivo, the pesticide rotenone induces degeneration of dopamine neurons and parkinsonian-like pathology in adult rats. In the current study, we utilized primary ventral mesencephalic (VM) cultures from E15 rats as an in vitro model to examine the mechanism underlying rotenone-induced death of dopamine neurons. After 11 h of exposure to 30 nm rotenone, the number of dopamine neurons identified by tyrosine hydroxylase (TH) immunostaining declined rapidly with only 23% of the neurons surviving. By contrast, 73% of total cells survived rotenone treatment, indicating that TH+ neurons are more sensitive to rotenone. Examination of the role of apoptosis in TH+ neuron death, revealed that 10 and 30 nm rotenone significantly increased the number of apoptotic TH+ neurons from 7% under control conditions to 38 and 55%, respectively. The increase in apoptotic TH+ neurons correlated with an increase in immunoreactivity for active caspase-3 in TH+ neurons. The caspase-3 inhibitor, DEVD, rescued a significant number of TH+ neurons from rotenone-induced death. Furthermore, this protective effect lasted for at least 32 h post-rotenone and DEVD exposure, indicating lasting neuroprotection achieved with an intervention prior to the death commitment point. Our results show for the first time in primary dopamine neurons that, at low nanomolar concentrations, rotenone induces caspase-3-mediated apoptosis. Understanding the mechanism of rotenone-induced apoptosis in dopamine neurons may contribute to the development of new neuroprotective strategies against Parkinson's disease. 相似文献
5.
6.
Ahmadi FA Grammatopoulos TN Poczobutt AM Jones SM Snell LD Das M Zawada WM 《Neurochemical research》2008,33(5):886-901
Among various types of neurons affected in Parkinson’s disease, dopamine (DA) neurons of the substantia nigra undergo the
most pronounced degeneration. Products of DA oxidation and consequent cellular damage have been hypothesized to contribute
to neuronal death. To examine whether elevated intracellular DA will selectively predispose the dopaminergic subpopulation
of nigral neurons to damage by an oxidative insult, we first cultured rat primary mesencephalic cells in the presence of rotenone
to elevate reactive oxygen species. Although MAP2+ neurons were more sensitive to rotenone-induced toxicity than type 1 astrocytes, rotenone affected equally both DA (TH+) neurons and MAP2+ neurons. In contrast, when intracellular DA concentration was elevated, DA neurons became selectively sensitized to rotenone.
Raising intracellular DA levels in primary DA neurons resulted in dopaminergic neuron death in the presence of subtoxic concentrations
of rotenone. Furthermore, mitochondrial superoxide dismutase mimetic, manganese (III) meso-tetrakis (4-benzoic acid) porphyrin, blocked activation of caspase-3, and consequent cell death. Our results demonstrate
that an inhibitor of mitochondrial complex I and increased cytosolic DA may cooperatively lead to conditions of elevated oxidative
stress and thereby promote selective demise of dopaminergic neurons. 相似文献
7.
8.
Zawada JF Yin G Steiner AR Yang J Naresh A Roy SM Gold DS Heinsohn HG Murray CJ 《Biotechnology and bioengineering》2011,108(7):1570-1578
Engineering robust protein production and purification of correctly folded biotherapeutic proteins in cell-based systems is often challenging due to the requirements for maintaining complex cellular networks for cell viability and the need to develop associated downstream processes that reproducibly yield biopharmaceutical products with high product quality. Here, we present an alternative Escherichia coli-based open cell-free synthesis (OCFS) system that is optimized for predictable high-yield protein synthesis and folding at any scale with straightforward downstream purification processes. We describe how the linear scalability of OCFS allows rapid process optimization of parameters affecting extract activation, gene sequence optimization, and redox folding conditions for disulfide bond formation at microliter scales. Efficient and predictable high-level protein production can then be achieved using batch processes in standard bioreactors. We show how a fully bioactive protein produced by OCFS from optimized frozen extract can be purified directly using a streamlined purification process that yields a biologically active cytokine, human granulocyte-macrophage colony-stimulating factor, produced at titers of 700 mg/L in 10 h. These results represent a milestone for in vitro protein synthesis, with potential for the cGMP production of disulfide-bonded biotherapeutic proteins. 相似文献
9.
Stancho Stanchev Zbigniew Zawada Lenka Monincová Lucie Bednárová Jiřina Slaninová Vladimír Fučík Václav Čeřovský 《Journal of peptide science》2014,20(9):725-735
The antimicrobial 40‐amino‐acid‐peptide lucifensin was synthesized by native chemical ligation (NCL) using N‐acylbenzimidazolinone (Nbz) as a linker group. NCL is a method in which a peptide bond between two discreet peptide chains is created. This method has been applied to the synthesis of long peptides and proteins when solid‐phase synthesis is imcompatible. Two models of ligation were developed: [15 + 25] Ala‐Cys and [19 + 21] His‐Cys. The [19 + 21] His‐Cys method gives lower yield because of the lower stability of 18‐peptide‐His‐Nbz‐CONH2 peptide, as suggested by density functional theory calculation. Acetamidomethyl‐deprotection and subsequent oxidation of the ligated linear lucifensin gave a mixture of lucifensin isomers, which differed in the location of their disulfide bridges only. The dominant isomer showed unnatural pairing of cysteines [C1?6], [C3?5], and [C2?4], which limits its ability to form α‐helical structure. The activity of isomeric lucifensin toward Bacillus subtilis, Staphylococcus aureus, and Micrococcus luteus was lower than that of the natural lucifensin. The desired product native lucifensin was prepared from this isomer using a one‐pot reduction with dithiotreitol and subsequent air oxidation in slightly alkaline medium. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
10.
Influenza viral entry into the host cell cytoplasm is accomplished by a process of membrane fusion mediated by the viral hemagglutinin protein. Hemagglutinin acts in a pH-triggered fashion, inserting a short fusion peptide into the host membrane followed by refolding of a coiled-coil structure to draw the viral envelope and host membranes together. Mutations to this fusion peptide provide an important window into viral fusion mechanisms and protein–membrane interactions. Here, we show that a well-described fusion peptide mutant, G1S, has a phenotype that depends strongly on the viral membrane context. The G1S mutant is well known to cause a “hemifusion” phenotype based on experiments in transfected cells, where cells expressing G1S hemagglutinin can undergo lipid mixing in a pH-triggered fashion similar to virus but will not support fusion pores. We compare fusion by the G1S hemagglutinin mutant expressed either in cells or in influenza virions and show that this hemifusion phenotype occurs in transfected cells but that native virions are able to support full fusion, albeit at a slower rate and 10–100 × reduced infectious titer. We explain this with a quantitative model where the G1S mutant, instead of causing an absolute block of fusion, alters the protein stoichiometry required for fusion. This change slightly slows fusion at high hemagglutinin density, as on the viral surface, but at lower hemagglutinin density produces a hemifusion phenotype. The quantitative model thus reproduces the observed virus–cell and cell–cell fusion phenotypes, yielding a unified explanation where membrane context can control the observed viral fusion phenotype. 相似文献