Anthrax
Hypocholesterolemia
Myocardial
7/23/2007/28
J Biol Chem. 2007 Feb 23;282(8):5225-36.
Epub 2006 Dec 1. Hsu
MH, Savas U, Griffin
KJ, Johnson
EF. Division of Biochemistry,
Department of Molecular and Experimental Medicine, The Scripps Research
Institute, La Jolla, California 92037, USA. This report provides the first
evidence that human P450 4F2 (CYP4F2) is induced by statins,
which are widely used to treat hypercholesterolemia. Real time PCR and immunoblots indicate that lovastatin
treatment increases expression of the endogenous CYP4F2 gene in human
primary hepatocytes and HepG2 cells. The effects
of lovastatin on gene expression are often
mediated through sterol regulatory element-binding proteins (SREBPs). Immunoblots indicate
that lovastatin-treated human hepatocytes
display increased proteolytic processing of
SREBP-2. In HepG2 cells, co-administration of a potent suppressor of
SREBP-2 activation, 25-hydroxycholesterol, inhibits CYP4F2 mRNA induction
by lovastatin. HepG2 cells transfected
with an expression vector for the active nuclear form of SREBP-1a
(nSREBP-1a) also display elevated endogenous CYP4F2 expression. Luciferase reporters containing the CYP4F2 proximal
promoter are transactivated by nSREBPs (-1a, -1c, and -2) or a dominant positive form
of the SREBP cleavage-activating protein (SCAP), which facilitates
activation of endogenous SREBPs. Lovastatin-induced reporter expression is inhibited by overexpressed Insig-1, which prevents proteolytic activation of endogenous SREBPs. Electrophoretic
mobility shift assays with in vitro translated nSREBP-1a identified two
SREBP binding sites at -169/-152 and -109/-92,
relative to the CYP4F2 transcription start site. Mutations in each site
abolish SREBP binding. Chromatin immunoprecipitation
experiments indicate that more SREBP-1 is associated with the CYP4F2
promoter after overexpression of nSREBP-1a. Transfection studies and mutagenesis indicate that the
-109/-92 region is the primary site responsible for the effects of statins. Collectively, these results demonstrate that SREBPs transactivate CYP4F2
transcription and that CYP4F2 induction by statins
is mediated by SREBP-2. PMID: 17142457 [PubMed
- indexed for MEDLINE] Atherosclerosis. 2007 Mar 23; [Epub ahead of print] Friedlander
Y, Schwartz
SM, Durst
R, Meiner V, Robertson
AS, Erez G, Leitersdorf E, Siscovick DS. Unit of
Epidemiology, BACKGROUND: Cholesterol
metabolism is mediated, in part, by the sterol-regulatory element binding
proteins (SREBPs) that are activated by a SREBP
cleavage-activating protein (SCAP). We examined whether coding variations
in the interacting domains of both genes, are related to early-onset MI
risk in a population-based case-control study from western PMID: 17383658 [PubMed
- as supplied by publisher] Atherosclerosis. 2007 Mar 23; [Epub ahead of print] Friedlander
Y, Schwartz
SM, Durst
R, Meiner V, Robertson
AS, Erez G, Leitersdorf E, Siscovick DS. Unit of
Epidemiology, BACKGROUND: Cholesterol
metabolism is mediated, in part, by the sterol-regulatory element binding
proteins (SREBPs) that are activated by a SREBP
cleavage-activating protein (SCAP). We examined whether coding variations
in the interacting domains of both genes, are related to early-onset MI
risk in a population-based case-control study from western PMID: 17383658 [PubMed
- as supplied by publisher] Biochim Biophys Acta.
2007 Jul 6; [Epub ahead of print] Macchiarulo A, Nuti R, Bellocchi D, Camaioni E, Pellicciari R. Dipartimento
di Chimica e Tecnologia del Farmaco, Universitą di Perugia, Via Indoleamine
2,3-dioxygenase (IDO) is an heme-containing
enzyme involved in the regulation of important immunological responses and
neurological processes. The enzyme catalyzes the oxidative cleavage of the pyrrole ring of the indole
nucleus of tryptophan (Trp)
to yield N-formylkynurenine, that is the initial
and rate limiting step of the kynurenine pathway.
Some indole derivatives have been reported to act
as effectors of the enzyme by enhancing its catalytic activity. On the
basis of the recent availability of the crystal structure of IDO, in this
work we investigate substrate recognition and enhancer binding to IDO using
molecular docking experiments. In addition, conformational transitions of
IDO in response to substrate and enhancer binding are studied using coarse
graining simulations with the program FIRST. The results enable us to
identify (i) the binding site of enhancer
modulators; (ii) the motion of an electrostatic gate that regulates the
access of the substrate to the catalytic site of the enzyme; (iii) the
movement of the anchoring region of a hairpin loop that may assist the
shuttle of substrates/products to/from the catalytic site of IDO. These
data, combined with available site-directed mutagenesis experiments, reveal
that conformational transitions of IDO in response to substrate and
enhancer binding are controlled by distinct combination of two
conformational states (open and close) of the above structural motifs. On
this basis, a molecular mechanism regarding substrate recognition and
activity enhancement by indole derivatives is proposed. PMID: 17644054 [PubMed
- as supplied by publisher] J Virol. 2007 Jul
11; [Epub ahead of print] Suh HS, Zhao
ML, Rivieccio M, Choi S, Connolly
E, Zhao
Y, Takikawa O, Brosnan CF, Lee
SC. Department of Pathology,
Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx NY
10461 and National Institute for Longevity Sciences, National Center for
Geriatrics and Gerontology, Obu, Japan. Indoleamine
2, 3-dioxygenase (IDO) is the first and rate-limiting enzyme in the kynurenine pathway of tryptophan
catabolism and has been implicated in neurotoxicity
and suppression of the antiviral T cell response in HIV encephalitis
(HIVE). Here we show that the toll-like receptor 3 (TLR3) ligand polyinosinic-polycytidylic
acid (PIC) induces the expression of IDO in human astrocytes. PIC was less potent than IFNgamma but more potent than IFNbeta
in inducing IDO. PIC induction of IDO was in part mediated by IFNbeta but not IFNgamma, and
both NF-kappaB and IRF3 were required. PIC also upregulated TLR3 thereby
augmenting the primary (IFNbeta) and secondary
(IDO and viperin) response genes upon subsequent
stimulation with PIC. In HIVE, the transcripts for TLR3, IFNbeta, IDO and viperin were
increased and IDO immunoreactivity was detected
in reactive astrocytes as well as macrophages and
microglia. PIC caused suppression of
intracellular replication of VSVg-env HIV and
human cytomegalovirus in a manner dependent on IRF3 and IDO. The
involvement of IDO was demonstrated by partial but significant reversal of
the PIC-mediated antiviral effect by IDO RNAi
and/or tryptophan supplementation. Importantly,
the cytokine IL-1 abolished IFNgamma-induced IDO
enzyme activity in a nitric oxide-dependent manner without suppressing
protein expression. Our results demonstrate that IDO is an innate antiviral
protein induced by dsRNA and suggest a
therapeutic utility for PIC in human viral infections. They also show that
IDO activity can be dissociated from protein expression, indicating that
the local CNS cytokine and nitric oxide environment determines IDO
function. PMID: 17626075 [PubMed
- as supplied by publisher] Int Immunopharmacol.
2006 Jun;6(6):1034-8. Epub
2006 Feb 3. Science.
2005 Jun 3;308(5727):1477-80. Rickert M, Wang
X, Boulanger MJ, Goriatcheva N, Garcia
KC. Departments of Microbiology
and Immunology, and Structural Biology, Stanford University School of
Medicine, 299 Campus Drive, Fairchild D319, Stanford, CA 94305-5124, USA. Interleukin-2 (IL-2) is an immunoregulatory cytokine that binds sequentially to
the alpha (IL-2Ralpha), beta (IL-2Rbeta), and common gamma chain (gammac) receptor subunits. Here we present the 2.8
angstrom crystal structure of a complex between human IL-2 and IL-2Ralpha,
which interact in a docking mode distinct from that of other cytokine receptor
complexes. IL-2Ralpha is composed of strand-swapped "sushi-like"
domains, unlike the classical cytokine receptor fold. As a result of this
domain swap, IL-2Ralpha uses a composite surface to dock into a groove on
IL-2 that also serves as a binding site for antagonist drugs. With this
complex, we now have representative structures for each class of hematopoietic cytokine receptor-docking modules. PMID: 15933202 [PubMed
- indexed for MEDLINE] The effect of therapeutic hypothermia on the
expression of inflammatory response genes following moderate traumatic
brain injury in the rat. genes
and may target more delayed responses underlying the secondary damage
following TBI. ICAM-1 gene expression in endothelial cells: Effects on the inhibition
of STAT3 phosphorylation. Bradykinin mimics ischemic preconditioning
by generating reactive oxygen species (ROS). To identify intermediate steps
leading to ROS generation, rabbit cardiomyocytes
were incubated in reduced MitoTracker Red that
becomes fluorescent after exposure to ROS. Fluorescence intensity in treated
cells was expressed as % of that in paired untreated cells. Bradykinin (500nM) caused 51+/-16% increase in ROS
generation (p<0.001). Co-incubation with either bradykinin
B2 receptor blocker HOE140 (5 micro M) or free radical scavenger
N-(2-mercaptopropionyl) glycine (1mM) prevented
this increase confirming the response was receptor-mediated and ROS were
actually being measured. Closing mitochondrial KATP (mKATP)channels with 5-hydroxydecanoate (5HD, 1mM) prevented
increased ROS generation. Bradykinin-induced ROS
generation was blocked by L-NAME (200 micro M) implicating nitric oxide as
an intermediate. Blockade of guanylyl cyclase with ODQ (10 micro M) aborted bradykinin-induced ROS generation, but not that from diazoxide, a direct opener of mKATP
channels. The PKG blocker 8-Br-cGMPS (25 micro M)
eliminated bradykinin's effect. Conversely,
direct activation of PKG with 8-pCPT-cGMP (100 micro M) increased ROS
generation (39+/-15%, p<0.004) similar to bradykinin.
This increase was blocked by 5HD. Finally, the nitric oxide donor SNAP (1
micro M)increased ROS by 34+/-6%. This increase
was also blocked by 5HD. In intact rabbit hearts bradykinin
(400nM) decreased infarction from 30.5+/-3.0% of the risk zone in control
hearts to 11.9+/-1.4% (p<0.01). This protection was aborted by either
L-NAME (200 micro M) or ODQ (2 micro M)(35.4+/-5.7%
and 30.4+/-3.0% infarction, resp., pNS vs control). Hence, bradykinin preconditions through receptor-mediated
production of nitric oxide which activates guanylyl
cyclase. The resulting cGMP
activates PKG that opens mKATP. Subsequent
release of ROS triggers cardioprotection.
Regulation of human cytochrome P450 4F2 expression by sterol regulatory
element-binding protein and lovastatin.
SREBP-2 and SCAP isoforms and risk of early onset myocardial infarction.
SREBP-2 and SCAP isoforms and risk of early onset myocardial infarction.
Molecular docking and spatial coarse graining
simulations as tools to investigate substrate recognition, enhancer binding
and conformational transitions in indoleamine-2,3-dioxygenase
(IDO).
Astrocyte indoleamine 2, 3 dioxygenase
(IDO) is induced by the TLR3 ligand poly IC:
mechanism of induction and role in anti-viral response.
IL-2 increased RANTES production and CD25
expression in cultured PBMCs only from
antiretroviral treated HIV-1+ patients with detectable viral loads.
Lozano
JM, Kindelan JM, Cabello A, Gonzalez
R, Solana
R, Pena
J.
Department of Immunology, Hospital "Reina
Sofia", University of Cordoba, Spain; Department of Virology, Pasteur
Institute of Paris, France.
In order to better understand the possible beneficial effects of
intermittent IL-2 treatment as complement of antiretroviral therapy in
HIV-1+ patients, we have measured the levels of RANTES in the supernatants
and the CD25 expression in cultured PBMCs obtained
from HIV-1+ individuals in presence of IL-2. The results showed a
significant increases in RANTES production and in the expression of CD25+
in the cultures with IL-2 of PBMC obtained from HIV-1+ patients with a
detectable viral load in comparison with both, HIV-1+ patients with no
detectable viral loads and with healthy individuals. These results suggest
that therapeutic IL-2 administered in addition to highly active
anti-retroviral therapy (HAART) may contribute to increase the effect of
this therapy by rising both RANTES production and CD25 expression only in
HIV-1+ patients with detectable viral loads.
PMID: 16644491 [PubMed - in process] 
The structure of
interleukin-2 complexed with its alpha receptor.
Truettner
JS, Suzuki T, Dietrich WD.
Department of Neurological Surgery, The Neurotrauma
Research Center, The Miami Project to Cure Paralysis, University of Miami
School of Medicine, Miami, FL 33136, USA.
Traumatic brain injury (TBI) initiates a cascade of cellular and molecular
responses including both pro- and anti-inflammatory. Although post-traumatic
hypothermia has been shown to improve outcome in various models of brain
injury, the underlying mechanisms responsible for these effects have not
been clarified. In this study, inflammation cDNA
arrays and semi-quantitative RT-PCR were used to detect genes that are
differentially regulated after TBI. In addition, the effect of
post-traumatic hypothermia on the expression of selective genes was also
studied. Rats (n = 6-8 per group) underwent moderate fluid-percussion (F-P)
brain injury with and without hypothermic treatment (33 degrees C/3 h). RNA
from 3-h or 24-h survival was analyzed for the expression of IL1-beta, IL2,
IL6, TGF-beta2, growth-regulated oncogene (GRO),
migration inhibitory factor (MIF), and MCP (a transcription factor). The
interleukins IL-1beta, IL-2, and IL-6 and TGF-beta and GRO were strongly upregulated early and transiently from 2- to 30-fold
over sham at 3 h, with normalization by 24 h. In contrast, the expressions
of MIF and MCP were both reduced by TBI compared to sham. Post-traumatic
hypothermia had no significant effect on the acute expression of the
majority of genes investigated. However, the expression of TGF-beta2 at 24
h was significantly reduced by temperature manipulation. The mechanism by
which post-traumatic hypothermia is protective may not involve a general
genetic response of the inflammatory genes. However, specific genes,
including TGF-beta2, may be altered and effect cell death mechanisms after
TBI. Hypothermia differentially regulates certain
PMID: 15922484 [PubMed - in process]
erase chain
reaction in unstimulated PBMC and in PBMC
incubated for 4h in the presence of concanavalin
A (ConA) or phorbol
12-myristate 13-acetate plus ionomycin (PMA/I).
Compared to unstimulated
cells, stimulation with ConA and PMA/I increased
the IL2 mRNA transcription in average by 300- and 20-fold, respectively.
Nevertheless, no significant differences in IL2 transcription between the
genotypes could be detected. These findings were confirmed by band shift
studies using different oligonucleotides
containing variations of the potential binding motif, which showed no
differences in the gel mobility after incubation with nuclear extract
containing GATA-3. The obtained results argue against an impact of this
polymorphism on the IL2 transcription and the genetic disease resistance in
sheep.
Resveratrol suppresses IL-6-induced
Wung
BS, Hsu MC, Wu CC, Hsieh CW.
Department of Applied Microbiology,
Resveratrol, a polyphenolic
phytoaxelin present in red wine, has been
suggested to protect against atherosclerosis and cardiovascular disease
because of its antioxidant effects. Intercellular adhesion molecule
(ICAM-1), induced by cytokines, has been hypothesized to play a role in the
early events during atherosclerosis. In this study we tested the effects of
resveratrol upon both IL-6-induced ICAM-1 gene
expression and its underlying signaling pathways in endothelial cells (ECs). Resveratrol was found
to inhibit both TNFalpha- and IL-6-induced ICAM-1
gene expression at the promoter, transcriptional and protein levels. Resveratrol also abrogates the tyr705 phosphorylation of STAT3 in IL-6-treated ECs, in a dose- and time-dependent manner. Although quercetin had similar effects, resveratrol
showed higher inhibitory properties following 2-4 h pretreatments. Resveratrol has been shown to induce the activity of
endothelial nitric oxide synthase (eNOS) and increase NO production. Consistent with this,
the treatment of ECs with a NO donor (SNAP)
reduces IL-6-induced STAT3 phosphorylation.
Conversely, exposure of ECs to a NOS inhibitor
reversed the effects of resveratrol upon
IL-6-induced STAT3 phosphorylation. Furthermore, ECs transfected with
constitutively active Rac1 (RacV12) showed increases in ICAM-1 promoter
activity, intracellular reactive oxygen species (ROS) levels and STAT3 phosphorylation, and these increases were attenuated by
resveratrol treatment. In summary, we demonstrate
for the first time that resveratrol inhibits
IL-6-induced ICAM-1 gene expression, in part, by interfering with Rac-mediated pathways via the attenuation of STAT3 phosphorylation. This study therefore provides
important new insights that may contribute to the proposed beneficial
effects of resveratrol in endothelial responses
to cytokines during inflammation.
PMID: 16150460 [PubMed - as supplied by
publisher]