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1.
Spontaneous inflammatory disease in transgenic rats expressing HLA-B27 and human beta 2m: an animal model of HLA-B27-associated human disorders 总被引:50,自引:0,他引:50
Humans who have inherited the human class I major histocompatibility allele HLA-B27 have a markedly increased risk of developing the multi-organ system diseases termed spondyloarthropathies. To investigate the role of B27 in these disorders, we introduced the B27 and human beta 2-microglobulin genes into rats, a species known to be quite susceptible to experimentally induced inflammatory disease. Rats from one transgenic line spontaneously developed inflammatory disease involving the gastrointestinal tract, peripheral and vertebral joints, male genital tract, skin, nails, and heart. This pattern of organ system involvement showed a striking resemblance to the B27-associated human disorders. These results establish that B27 plays a central role in the pathogenesis of the multi-organ system processes of the spondyloarthropathies. Elucidation of the role of B27 should be facilitated by this transgenic model. 相似文献
2.
Reconstitution of lipoprotein(a) by infusion of human low density lipoprotein into transgenic mice expressing human apolipoprotein(a). 总被引:15,自引:0,他引:15
G Chiesa H H Hobbs M L Koschinsky R M Lawn S D Maika R E Hammer 《The Journal of biological chemistry》1992,267(34):24369-24374
Lipoprotein(a) (Lp(a)) is an atherosclerosis-causing lipoprotein that circulates in human plasma as a complex of low density lipoprotein (LDL) and apolipoprotein(a) (apo(a)). It is not known whether apo(a) attaches to LDL within hepatocytes prior to secretion or in plasma subsequent to secretion. Here we describe the development of a line of mice expressing the human apo(a) transgene under the control of the murine transferrin promoter. The apo(a) was secreted into the plasma, but circulated free of lipoproteins. When human (h)-LDL was injected intravenously, the circulating apo(a) rapidly associated with the lipoproteins, as determined by nondenaturing gel electrophoresis. Human HDL and mouse LDL had no such effect. When h-VLDL was injected, there was a delayed association of apo(a) with the lipoprotein fraction which suggests that apo(a) preferentially associated with a metabolic product of VLDL. The complex of apo(a) with LDL formed both in vivo and in vitro was resistant to boiling in the presence of detergents and denaturants, but was resolved upon disulfide reduction. These studies suggest that apo(a) fails to associate with mouse lipoproteins due to structural differences between human and mouse LDL, and that Lp(a) formation can occur in plasma through the association of apo(a) with circulating LDL. 相似文献
3.
4.
Lasarte JJ Casares N Gorraiz M Hervás-Stubbs S Arribillaga L Mansilla C Durantez M Llopiz D Sarobe P Borrás-Cuesta F Prieto J Leclerc C 《Journal of immunology (Baltimore, Md. : 1950)》2007,178(2):748-756
Vaccination strategies based on the in vivo targeting of Ags to dendritic cells (DCs) are needed to improve the induction of specific T cell immunity against tumors and infectious agents. In this study, we have used a recombinant protein encompassing the extra domain A from fibronectin (EDA), an endogenous ligand for TLR4, to deliver Ags to TLR4-expressing DC. The purified EDA protein was shown to bind to TLR4-expressing HEK293 cells and to activate the TLR4 signaling pathway. EDA also stimulated the production by DC of proinflammatory cytokines such as IL-12 or TNF-alpha and induced their maturation in vitro and in vivo. A fusion protein between EDA and a cytotoxic T cell epitope from OVA efficiently presented this epitope to specific T cells and induced the in vivo activation of a strong and specific CTL response. Moreover, a fusion protein containing EDA and the full OVA also improved OVA presentation by DC and induced CTL responses in vivo. These EDA recombinant proteins protected mice from a challenge with tumor cells expressing OVA. These results strongly suggest that the fibronectin extra domain A may serve as a suitable Ag carrier for the development of antiviral or antitumoral vaccines. 相似文献
5.
Förster C Zydek M Rothkegel M Wu Z Gallin C Geßner R Lisdat F Fürste JP 《Biochemical and biophysical research communications》2012,419(1):60-65
'Locked nucleic acids' (LNAs) are sugar modified nucleic acids containing the 2'-O-4'C-methylene-β-D-ribofuranoses. The substitution of RNAs with LNAs leads to an enhanced thermostability. Aptamers are nucleic acids, which are selected for specific target binding from a large library pool by the 'SELEX' method. Introduction of modified nucleic acids into aptamers can improve their stability. The stem region of a ricin A chain RNA aptamer was substituted by locked nucleic acids. Different constructs of the LNA-substituted aptamers were examined for their thermostability, binding activity, folding and RNase sensitivity as compared to the natural RNA counterpart. The LNA-modified aptamers were active in target binding, while the loop regions and the adjacent stem nucleotides remained unsubstituted. The thermostability and RNase resistance of LNA substituted aptamers were enhanced as compared to the native RNA aptamer. This study supports the approach to substitute the aptamer stem region by LNAs and to leave the loop region unmodified, which is responsible for ligand binding. Thus, LNAs possess an encouraging potential for the development of new stabilized nucleic acids and will promote future diagnostic and therapeutic applications. 相似文献
6.
Raphaël Plasson Maika Tsuji Masazumi Kamata Kouichi Asakura 《Origins of life and evolution of the biosphere》2011,41(5):413-435
A good comprehension of the reactivity of peptides in aqueous solution is fundamental in prebiotic chemistry, namely for understanding
their stability and behavior in primitive oceans. Relying on the stereoselectivity of the involved reactions, there is a huge
interest in amino acid derivatives for explaining the spontaneous emergence of homochirality on primitive Earth. The corresponding
kinetic and thermodynamic parameters are however still poorly known in the literature. We studied the reactivity of alanylalanine
in acidic to neutral conditions as a model system. The hydrolysis into amino acids, the epimerization of the N-terminal residue,
and the cyclization into diketopiperazine could be successfully identified and studied. This kinetic investigation highlighted
interesting behaviors. Complex mechanisms were observed in very acidic conditions. The relative kinetic stability of the diastereoisomers
of the dipeptide is highly dependent of the pH, with the possibility to dynamically destabilize the thermodynamically more
stable diastereoisomers. The existence of the cyclization of dipeptides adds complexity to the system. On one hand it brings
additional stereoselectivities; on the other hand fast racemization of heterochiral dipeptides is obtained. 相似文献
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8.
UDP-induced relaxation is enhanced in aorta from female obese Otsuka Long–Evans Tokushima Fatty rats
Shota Kobayashi Takayuki Matsumoto Makoto Ando Maika Iguchi Shun Watanabe Kumiko Taguchi Tsuneo Kobayashi 《Purinergic signalling》2018,14(1):91-96
Uridine 5′-diphosphate (UDP) plays an important role in controlling vascular tone; however, UDP-mediated response in metabolic syndromes, including obesity and type 2 diabetes in females, remains unclear. In this study, we investigated UDP-mediated response in the aorta of female obese Otsuka Long–Evans Tokushima Fatty (OLETF) rats and control Long–Evans Tokushima Otsuka (LETO) rats. In OLETF rat aortas precontracted by phenylephrine (PE) (vs. LETO), (1) UDP-induced relaxation was increased, whereas acetylcholine (ACh)-induced relaxation was decreased; (2) no UDP- or ACh-induced relaxations were observed in endothelial denudation, whereas UDP-induced small contraction was observed; and (3) NG-nitro-L-arginine [L-NNA, a nitric oxide (NO) synthase inhibitor] eliminated UDP-induced relaxation and small contraction, whereas caused contrasting responses by ACh, including slight relaxations (LETO) and contractions (OLETF). Indomethacin, a cyclooxygenase inhibitor, eliminated the difference in UDP- and ACh-induced relaxations between the groups by increased UDP-induced relaxation in the LETO group and increased ACh-induced relaxation in the OLETF group. MRS2578, a P2Y6 receptor antagonist, eliminated the difference in UDP-induced relaxations between the groups by decreasing UDP-induced relaxation in the OLETF group. MRS2578 had no effect on UDP-induced contraction in endothelium-denuded aortas. Therefore, these findings demonstrate opposite trends of relaxations by UDP and ACh in OLETF and LETO rat aortas. These differences may be attributed to the imbalance between NO and vasoconstrictor prostanoids upon stimulations. Increased UDP-induced relaxation in OLETF rat aorta may be caused by the activation of endothelial MRS2578-sensitive P2Y6 receptor. 相似文献
9.
Maika Deffieu Ingrid Bhatia-Ki??ová Bénédicte Salin Anne Galinier Stéphen Manon Nadine Camougrand 《The Journal of biological chemistry》2009,284(22):14828-14837
The antioxidant N-acetyl-l-cysteine prevented the
autophagy-dependent delivery of mitochondria to the vacuoles, as examined by
fluorescence microscopy of mitochondria-targeted green fluorescent protein,
transmission electron microscopy, and Western blot analysis of mitochondrial
proteins. The effect of N-acetyl-l-cysteine was specific
to mitochondrial autophagy (mitophagy). Indeed, autophagy-dependent activation
of alkaline phosphatase and the presence of hallmarks of non-selective
microautophagy were not altered by N-acetyl-l-cysteine.
The effect of N-acetyl-l-cysteine was not related to its
scavenging properties, but rather to its fueling effect of the glutathione
pool. As a matter of fact, the decrease of the glutathione pool induced by
chemical or genetical manipulation did stimulate mitophagy but not general
autophagy. Conversely, the addition of a cell-permeable form of glutathione
inhibited mitophagy. Inhibition of glutathione synthesis had no effect in the
strain Δuth1, which is deficient in selective mitochondrial
degradation. These data show that mitophagy can be regulated independently of
general autophagy, and that its implementation may depend on the cellular
redox status.Autophagy is a major pathway for the lysosomal/vacuolar delivery of
long-lived proteins and organelles, where they are degraded and recycled.
Autophagy plays a crucial role in differentiation and cellular response to
stress and is conserved in eukaryotic cells from yeast to mammals
(1,
2). The main form of autophagy,
macroautophagy, involves the non-selective sequestration of large portions of
the cytoplasm into double-membrane structures termed autophagosomes, and their
delivery to the vacuole/lysosome for degradation. Another process,
microautophagy, involves the direct sequestration of parts of the cytoplasm by
vacuole/lysosomes. The two processes coexist in yeast cells but their extent
may depend on different factors including metabolic state: for example, we
have observed that nitrogen-starved lactate-grown yeast cells develop
microautophagy, whereas nitrogen-starved glucose-grown cells preferentially
develop macroautophagy (3).Both macroautophagy and microautophagy are essentially non-selective, in
the way that autophagosomes and vacuole invaginations do not appear to
discriminate the sequestered material. However, selective forms of autophagy
have been observed (4) that
target namely peroxisomes (5,
6), chromatin
(7,
8), endoplasmic reticulum
(9), ribosomes
(10), and mitochondria
(3,
11–13).
Although non-selective autophagy plays an essential role in survival by
nitrogen starvation, by providing amino acids to the cell, selective autophagy
is more likely to have a function in the maintenance of cellular structures,
both under normal conditions as a “housecleaning” process, and
under stress conditions by eliminating altered organelles and macromolecular
structures
(14–16).
Selective autophagy targeting mitochondria, termed mitophagy, may be
particularly relevant to stress conditions. The mitochondrial respiratory
chain is both the main site and target of
ROS4 production
(17). Consequently, the
maintenance of a pool of healthy mitochondria is a crucial challenge for the
cells. The progressive accumulation of altered mitochondria
(18) caused by the loss of
efficiency of the maintenance process (degradation/biogenesis de
novo) is often considered as a major cause of cellular aging
(19–23).
In mammalian cells, autophagic removal of mitochondria has been shown to be
triggered following induction/blockade of apoptosis
(23), suggesting that
autophagy of mitochondria was required for cell survival following
mitochondria injury (14).
Consistent with this idea, a direct alteration of mitochondrial permeability
properties has been shown to induce mitochondrial autophagy
(13,
24,
25). Furthermore, inactivation
of catalase induced the autophagic elimination of altered mitochondria
(26). In the yeast
Saccharomyces cerevisiae, the alteration of
F0F1-ATPase biogenesis in a conditional mutant has been
shown to trigger autophagy
(27). Alterations of
mitochondrial ion homeostasis caused by the inactivation of the
K+/H+ exchanger was shown to cause both autophagy and
mitophagy (28). We have
reported that treatment of cells with rapamycin induced early ROS production
and mitochondrial lipid oxidation that could be inhibited by the hydrophobic
antioxidant resveratrol (29).
Furthermore, resveratrol treatment impaired autophagic degradation of both
cytosolic and mitochondrial proteins and delayed rapamycin-induced cell death,
suggesting that mitochondrial oxidation events may play a crucial role in the
regulation of autophagy. This existence of regulation of autophagy by ROS has
received molecular support in HeLa cells
(30): these authors showed
that starvation stimulated ROS production, namely H2O2,
which was essential for autophagy. Furthermore, they identified the cysteine
protease hsAtg4 as a direct target for oxidation by
H2O2. This provided a possible connection between the
mitochondrial status and regulation of autophagy.Investigations of mitochondrial autophagy in nitrogen-starved lactate-grown
yeast cells have established the existence of two distinct processes: the
first one occurring very early, is selective for mitochondria and is dependent
on the presence of the mitochondrial protein Uth1p; the second one occurring
later, is not selective for mitochondria, is not dependent on Uth1p, and is a
form of bulk microautophagy
(3). The absence of the
selective process in the Δuth1 mutant strongly delays and
decreases mitochondrial protein degradation
(3,
12). The putative protein
phosphatase Aup1p has been also shown to be essential in inducing mitophagy
(31). Additionally several Atg
proteins were shown to be involved in vacuolar sequestration of mitochondrial
GFP (3,
12,
32,
33). Recently, the protein
Atg11p, which had been already identified as an essential protein for
selective autophagy has also been reported as being essential for mitophagy
(33).The question remains as to identify of the signals that trigger selective
mitophagy. It is particularly intriguing that selective mitophagy is activated
very early after the shift to a nitrogen-deprived medium
(3). Furthermore, selective
mitophagy is very active on lactate-grown cells (with fully differentiated
mitochondria) but is nearly absent in glucose-grown cells
(3). In the present paper, we
investigated the relationships between the redox status of the cells and
selective mitophagy, namely by manipulating glutathione. Our results support
the view that redox imbalance is a trigger for the selective elimination of
mitochondria. 相似文献
10.
Kidd JM Graves T Newman TL Fulton R Hayden HS Malig M Kallicki J Kaul R Wilson RK Eichler EE 《Cell》2010,143(5):837-847
Understanding the prevailing mutational mechanisms responsible for human genome structural variation requires uniformity in the discovery of allelic variants and precision in terms of breakpoint delineation. We develop a resource based on capillary end sequencing of 13.8 million fosmid clones from 17 human genomes and characterize the complete sequence of 1054 large structural variants corresponding to 589 deletions, 384 insertions, and 81 inversions. We analyze the 2081 breakpoint junctions and infer potential mechanism of origin. Three mechanisms account for the bulk of germline structural variation: microhomology-mediated processes involving short (2-20 bp) stretches of sequence (28%), nonallelic homologous recombination (22%), and L1 retrotransposition (19%). The high quality and long-range continuity of the sequence reveals more complex mutational mechanisms, including repeat-mediated inversions and gene conversion, that are most often missed by other methods, such as comparative genomic hybridization, single nucleotide polymorphism microarrays, and next-generation sequencing. 相似文献