bluuebunny/crossref_metadata_2025 huggingface dataset:
Retardation of Atherosclerosis by Overexpression of Catalase or Both Cu/Zn-Superoxide Dismutase and Catalase in Mice Lacking Apolipoprotein E
Authors: Yang Hong , Roberts L. Jackson , Shi Ming Jian , Zhou Li Chun , Ballard Billy R. , Richardson Arlan , Guo Zhong Mao
Published: November 2004

Oxidative stress has been suggested to potentiate atherogenesis. However, studies that have investigated the effect of antioxidants on atherosclerosis showed inconsistent results, ie, atherosclerosis was either retarded or not changed by dietary antioxidants. This report directly examined the effect of overexpressing Cu/Zn-superoxide dismutase (Cu/Zn-SOD) and/or catalase on atherosclerosis and lipid peroxidation in mice lacking apolipoprotein E (
ApoE
−/−
). Based on lipid staining of the en face of the aorta tree and the serial sections of the proximal aorta,
ApoE
−/−
mice overexpressing catalase or both Cu/Zn-SOD and catalase had smaller and relatively early stages of atherosclerotic lesions (eg, foam cells and free lipids) when compared with
ApoE
−/−
mice, who developed more advanced lesions (eg, fibrous caps and acellular areas). In addition, the retarded development of atherosclerosis was correlated with a reduced F
2
-isoprostanes in the plasma and aortas in
ApoE
−/−
mice overexpressing catalase or both Cu/Zn-SOD and catalase. In contrast, the levels of F
2
-isoprostanes and atherosclerosis in the
ApoE
−/−
mice overexpressing Cu/Zn-SOD alone were comparable to
ApoE
−/−
control mice. These observations implied that endogenously produced hydrogen peroxide, but not superoxide anions, contributed to the formation of oxidized lipids and the development of atherosclerosis in
ApoE
−/−
mice.
Fibulin-5 Is a Novel Binding Protein for Extracellular Superoxide Dismutase
Authors: Nguyen Andrew D. , Itoh Shinichi , Jeney Viktoria , Yanagisawa Hiromi , Fujimoto Mitsuaki , Ushio-Fukai Masuko , Fukai Tohru
Published: November 2004

The extracellular superoxide dismutase (ecSOD) plays an important role in atherosclerosis and endothelial function by modulating levels of the superoxide anion (O
2
·−
) in the extracellular space. Although heparan sulfate proteoglycan is an important ligand for ecSOD, little is known about other biological binding partners of ecSOD. The goal of this study was to identify novel proteins that interact with ecSOD. A yeast two-hybrid screening of a human aorta cDNA library using ecSOD as bait identified fibulin-5 as a predominant binding protein for ecSOD. Further analysis showed that the binding domain of ecSOD within fibulin-5 mapped to its C-terminal domain. In vitro pulldown assays and coimmunoprecipitation analysis further confirmed that ecSOD interacts with fibulin-5 in vitro and in vivo. Studies using fibulin-5
−/−
mice indicated that fibulin-5 is required for binding of ecSOD to vascular tissue. Importantly, the decrease in tissue-bound ecSOD levels in aortas from fibulin-5
−/−
mice was associated with an increase in vascular O
2
·−
levels. Furthermore, immunohistochemical analysis using ApoE
−/−
mice suggested a codistribution of ecSOD and fibulin-5 in atherosclerotic vessels. In summary, we provide in this study the first evidence that the ecSOD-fibulin-5 interaction is required for ecSOD binding to vascular tissues, thereby regulating vascular O
2
·−
levels. This interaction may represent a novel mechanism for controlling vascular redox state in the extracellular space in various cardiovascular diseases such as atherosclerosis and hypertension in which oxidative stress is increased.
Induction of the MMP-14 Gene in Macrophages of the Atherosclerotic Plaque
Authors: Ray Bimal K. , Shakya Arvind , Turk James R. , Apte Suneel S. , Ray Alpana
Published: November 2004

Based on epidemiological and pathological studies, it is becoming increasingly clear that matrix metalloproteinases (MMPs) play an important role in the pathogenesis of atherosclerosis by participating in vascular remodeling, smooth muscle cell migration, and plaque disruption. MMP-14, because of its unique ability to cause pericellular degradation, its broad substrate specificity, its synthesis in an active form, and its ability to activate other matrix metalloproteinases, is recognized as a prominent member of this family. MMP-14 is detected at high levels in the atherosclerotic plaque. To understand the induction mechanism of MMP-14 under atherogenic conditions, we examined its expression pattern in response to oxidized low-density lipoproteins (ox-LDLs) that are believed to play an important role in atherogenesis. We report that in macrophages, ox-LDLs markedly elevate the levels of MMP-14 mRNA and protein. The
cis
-acting elements supporting this increase were identified to be present within −213 and −1 nucleotides of the MMP-14 promoter. DNase I protection assay revealed, within this region, two major elements, of which one serves as the DNA-binding site for SAF-1 transcription factor. Increased binding of SAF-1 to the MMP-14 promoter correlated with the transcriptional upregulation of MMP-14 gene. Furthermore, induction of endogenous MMP-14 gene, MMP-14 promoter driven reporter gene expression and MMP-2 processing activity during overexpression of SAF-1 and coexpression of SAF-1 and MMP-14 in the macrophages present in the atherosclerotic plaque implicate SAF-1 as a key regulator of MMP-14 gene induction in macrophage cells.
Transforming Growth Factor β–SMAD2 Signaling Regulates Aortic Arch Innervation and Development
Authors: Molin Daniel G.M. , Poelmann Robert E. , DeRuiter Marco C. , Azhar Mohamad , Doetschman Thomas , Gittenberger-de Groot Adriana C.
Published: November 2004

Aortic arch interruptions in humans and animal models are mainly caused by aberrant development of the fourth pharyngeal arch artery. Little is known about the maturation of this vessel during normal and abnormal development, which is the subject of this study.
Tgfβ2
knockout mice that present with fourth artery defects have been associated with defective neural crest cell migration. In this study, we concentrated on pharyngeal arch artery development during developmental days 12.5 to 18.5, focusing on neural crest cell migration using a Wnt1-Cre by R26R neural crest cell reporter mouse. Fourth arch artery maturation was studied with antibodies directed against smooth muscle α-actin and neural NCAM-1 and RMO-270. For diminished transforming growth factor β (TGF-β) signaling, SMAD2 and fibronectin have been analyzed. Neural crest migration and differentiation into smooth muscle cells is unaltered in mutants, regardless of the cardiovascular defect found; however, innervation of the fourth arch artery is affected. Absent staining for nuclear SMAD2, NCAM-1, and RMO-270 in the fourth artery in mutant coincides with severe defects of this segment. Likewise, fibronectin expression is diminished in these cases. From these data we conclude the following: (1) neural crest cell migration is not a common denominator in cardiovascular defects of
Tgfβ2

−/−

mice; (2) fourth arch artery maturation is a complex process involving innervation; and (3) TGF-β2 depletion diminishes SMAD2-signaling in the fourth arch artery and coincides with reduced vascular NCAM-1 expression and neural innervation of this artery. We hypothesize that disturbed maturation of the fourth pharyngeal arch artery, and especially abrogated vascular innervation, will result in fourth arch interruptions.
Poststroke “Pushing”
Authors: Danells Cynthia J. , Black Sandra E. , Gladstone David J. , McIlroy William E.
Published: November 2004

Background and Purpose—

Patients with hemiparetic stroke have impaired balance control. Some patients (“pushers”) are resistant to accepting weight on and actively “push” away from the nonparetic side. This research identified pushers from stroke patients with moderate to severe hemiparesis and examined longitudinal changes in symptoms, level of impairment, and functional independence.

Methods—

Prospective sample of hemiparetic stroke patients (n=65) located in Toronto, Canada. Detailed clinical assessments were performed within 10 days postonset, at 6 weeks, and at 3 months.

Results—

At 1 week after stroke, 63% of patients demonstrated features of pushing. In 62% of pushers, symptoms resolved by 6 weeks, whereas in 21%, pushing symptoms persisted at 3 months. Motor recovery and functional abilities at 3 months were significantly lower among the pushers compared with the nonpushers. Pushers also had a significantly longer hospital length of stay (89 days versus 57 days). It is noteworthy that motor and functional recovery improved significantly over the 3-month study period for both pushers and nonpushers.

Conclusions—

Identification of stroke patients with pushing symptoms has prognostic implications for recovery. In light of this potential recovery, rehabilitation specialists need to refine treatment approaches for the pushers to further improve functional outcome.
Nietzsche's New Grounding of The Metaphysical: Sensuousness and the Subversion of Plato and Platonism
Authors: Sena Marylou
Published: November 2004

This essay gives an extensive treatment of Heidegger's confrontation (

Auseinander-setzung

) with Nietzsche' thought. It argues that Heidegger's confrontation entails situating what Heidegger calls Nietzsche's "transformed" understanding of the sensuous outside the metaphysics of both Plato and Platonism. The essay establishes, by the end of the second section, that Heidegger's confrontation with Nietzsche's thought culminates with the insight that for Nietzsche sensuousness is metaphysical. The third section of the essay takes as its point of departure Heidegger's intimation at the conclusion of

The Will to Power as Art

, where he advances the

inference

that Nietzsche's new grounding of the metaphysical in sensuousness

brings along with it

"readiness for the gods." The essay offers explicit support for Heidegger's intimation through an analysis of three essential steps, outlined by Nietzsche in

The Birth of Tragedy

, in which sensuousness proves to be indicative of a way of access to the gods, the dual gods, Apollo and Dionysus, at the origin of Greek tragedy.
Stars and Constellations: The Difference Between Gadamer and Derrida
Authors: Di Cesare Donatella
Published: November 2004

What is the difference between hermeneutics and deconstruction? This essay provides an answer by following the guiding thread of

understanding

that was already brought to the fore in Paris during the "improbable debate" between Gadamer and Derrida. Maybe there was and still is a "dialogue" between the two most important currents of continental philosophy, as Derrida suggests in his talk commemorating Gadamer at Heidelberg in 2002. It is a dialogue that passes through poetry, and above all the poems of Celan. In this way, the distance or the proximity between hermeneutics and deconstruction rests in the meaning of understanding: the one beginning from the

uninterrupted dialogue

, the other from the

difference of interruption

. Through a phenomenology of saying and of understanding, this essay asks at the same time how the differences of deconstruction are the stars necessary for the constellation of hermeneutics, and how the constellation is nevertheless necessary for every new star. It is perhaps the

Schibboleth

of Celan that indicates the point of orientation.
Innovating Across Cultural Boundaries: Applying Conflict Theory to Develop a Common Approach
Authors: Wong Alfred , Tjosvold Dean
Published: November 2004

Diversity of people and perspectives can contribute to the ability of teams to develop and implement innovation in organizations. However, to do so they must manage their conflicts. Considerable research in the West and recent studies in China have documented the value of a cooperative approach to conflict for teamwork and innovation in collectivist as well as individualist cultures. When team members attempt to resolve their disputes for mutual benefit, they have been found to make high quality decisions to which they are committed. This article proposes that diverse people can use this theory to develop common values, norms, and procedures that are accessible and effective for all cultural groups.
Neuronal Survival and p73/p63/p53: A Family Affair
Authors: Jacobs W. Bradley , Walsh Gregory S. , Miller Freda D.
Published: November 2004

Elucidating the mechanisms that regulate the life versus death of mammalian neurons is important not only for our understanding of the normal biology of the nervous system but also for our efforts to devise approaches to maintain neuronal survival in the face of traumatic injury or neurodegenerative disorders. Here, we review the emerging evidence that a key survival/death checkpoint in both peripheral and central neurons involves the p53 tumor suppressor and its newly discovered family members, p73 and p63. The full-length isoforms of these proteins function as proapoptotic proteins, whereas naturally occurring N-terminal truncated variants of p73 and p63 act as prosurvival proteins, at least partially by antagonizing the full-length family members. The authors propose that together, these isoforms comprise an upstream rheostat that sums different environmental cues to ultimately determine neuronal survival during development, during neuronal maintenance in adult animals, and even following traumatic injury.
Zn2+ Ions: Modulators of Excitatory and Inhibitory Synaptic Activity
Authors: Smart Trevor G. , Hosie Alastair M. , Miller Paul S.
Published: November 2004

The role of Zn2+ in the CNS has remained enigmatic for several decades. This divalent cation is accumulated by specific neurons into synaptic vesicles and can be released by stimulation in a Ca2+-dependent manner. Using Zn2+ fluorophores, radiolabeled Zn2+, and selective chelators, the location of this ion and its release pattern have been established across the brain. Given the distribution and possible release under physiological conditions, Zn2+ has the potential to act as a modulator of both excitatory and inhibitory neurotransmission. Excitatory N-methyl-D-aspartate (NMDA) receptors are directly inhibited by Zn2+, whereas non-NMDA receptors appear relatively unaffected. In contrast, inhibitory transmission mediated via GABAAreceptors can be potentiated via a presynaptic mechanism, influencing transmitter release; however, although some tonic GABAergic inhibition may be suppressed by Zn2+, most synaptic GABA receptors are unlikely to be modulated directly by this cation. In the spinal cord, glycinergic transmission may also be affected by Zn2+ causing potentiation. Recently, the penetration of synaptically released Zn2+ into neurons suggests that this ion has the potential to act as a direct transmitter, by affecting postsynaptic signaling pathways. Taken overall, present studies are broadly supportive of a neuromodulatory role for Zn2+ at specific excitatory and inhibitory synapses.
Retinoic Acid Signaling in the Nervous System of Adult Vertebrates
Authors: Mey Jörg , Mccaffery Peter
Published: November 2004

The majority of the functions of vitamin A are carried out by its metabolite, retinoic acid (RA), a potent transcriptional activator acting through members of the nuclear receptor family of transcription factors. In the CNS, RA was first recognized to be essential for the control of patterning and differentiation in the developing embryo. It has recently come to light, however, that many of the same functions that RA directs in the embryo are involved in the regulation of plasticity and regeneration in the adult brain. The same intricate metabolic control system of synthetic and catabolic enzymes, combined with cytoplasmic binding proteins, is used in both embryo and adult to create regions of high and low RA to modulate gene transcription. This review summarizes some of the discoveries in the new field of retinoid neurobiology including its functions in neural plasticity and LTP in the hippocampus; its possible role in motor disorders such as Parkinson’s disease, motoneuron disease, and Huntington’s disease; its role in regeneration after sciatic nerve and spinal cord injury; and its possible involvement in psychiatric diseases such as depression.
Translational Control at the Synapse
Authors: Wang Huidong , Tiedge Henri
Published: November 2004

The strength of synaptic connections can undergo long-lasting changes, and such long-term plasticity is thought to underlie higher brain functions such as learning and memory. De novo synthesis of proteins is required for such plastic changes. This model is now supported by several lines of experimental data. Components of translational machinery have been identified in dendrites, including ribosomes, translational factors, numerous RNAs, and components of posttranslational secretory pathways. Various RNAs have been shown to be actively and rapidly transported to dendrites. Dendritic RNAs typically contain transport-specifying elements (dendritic targeting elements). Such dendritic targeting elements associate with transacting factors to form transport-competent ribonucleoprotein particles. It is assumed that molecular motors mediate transport of such particles along dendritic cytoskeletal elements. Once an mRNA has arrived at its dendritic destination site, appropriate spatiotemporal control of its translation, for example, in response to transsynaptic activity, becomes vital. Such local translational control, recent evidence indicates, is implemented at different levels and through various pathways. In the default state, translation is assumed to be repressed, and several mechanisms, some including small untranslated RNAs, have been proposed to contribute to such repression. Translational control at the synapse thus provides a molecular basis for the long-term, input-specific modulation of synaptic strength.
Huntington and its Role in Neuronal Degeneration
Authors: Li Shi-Hua , Li Xiao-Jiang
Published: November 2004

Huntington’s disease results from a polyglutamine expansion in the N-terminal region of huntingtin (htt). This abnormality causes protein aggregation and leads to neurotoxicity. Despite its widespread expression in the brain and body, mutant htt causes selective neurodegeneration in Huntington’s disease patient brains. However, Huntington’s disease mouse models expressing mutant htt do not have obvious neurodegeneration despite significant neurological symptoms. Most Huntington’s disease mouse models display the accumulation of toxic N-terminal mutant htt fragments in both the nucleus and neuronal processes, suggesting that these subcellular sites are hotspots for the early neuropathology of Huntington’s disease. Intranuclear htt affects gene expression and may cause neuronal dysfunction. Mutant htt in neuronal processes affects axonal transport and induces degeneration, and these effects may be more relevant to the selective neurodegeneration in Huntington’s disease. Growing evidence has also suggested that mutant htt mediates multiple pathological pathways. This review discusses the early pathological changes identified in Huntington’s disease cellular and animal models. These changes may be the causes of neurode-generation.
The hereditary hemochromatosis protein, HFE, lowers intracellular iron levels independently of transferrin receptor 1 in TRVb cells
Authors: Carlson Hanqian , Zhang An-Sheng , Fleming William H. , Enns Caroline A.
Published: November 2004

Hereditary hemochromatosis (HH) is an autosomal recessive disease that leads to parenchymal iron accumulation. The most common form of HH is caused by a single amino acid substitution in the HH protein, HFE, but the mechanism by which HFE regulates iron homeostasis is not known. In the absence of transferrin (Tf), HFE interacts with transferrin receptor 1 (TfR1) and the 2 proteins co-internalize, and in vitro studies have shown that HFE and Tf compete for TfR1 binding. Using a cell line lacking endogenous transferrin receptors (TRVb cells) transfected with different forms of HFE and TfR1, we demonstrate that even at low concentrations Tf competes effectively with HFE for binding to TfR1 on living cells. Transfection of TRVb cells or the derivative line TRVb1 (which stably expresses human TfR1) with HFE resulted in lower ferritin levels and decreased Fe2+ uptake. These data indicate that HFE can regulate intracellular iron storage independently of its interaction with TfR1. Earlier studies found that in HeLa cells, HFE expression lowers Tf-mediated iron uptake; here we show that HFE lowers non–Tf-bound iron in TRVb cells and add to a growing body of evidence that HFE may play different roles in different cell types.
Platelet P-selectin is required for pulmonary eosinophil and lymphocyte recruitment in a murine model of allergic inflammation
Authors: Pitchford Simon C. , Momi Stefania , Giannini Silvia , Casali Lucio , Spina Domenico , Page Clive P. , Gresele Paolo
Published: November 2004

Platelets are necessary for lung leukocyte recruitment in a murine model of allergic inflammation, and platelet–leukocyte aggregates are formed in circulating blood of patients with asthma after allergen exposure. However, it is unknown how platelets induce pulmonary leukocyte recruitment in asthma. Here, we have investigated the importance of platelet adhesion molecule expression on pulmonary eosinophil and lymphocyte recruitment and on leukocyte CD11b and very late antigen (VLA)–4 expression in mice. Pulmonary leukocyte recruitment in platelet-depleted mice (sensitized and exposed to ovalbumin) transfused with fixed, unstimulated platelets (FUSPs) was abolished, whereas transfusion with platelets stimulated and fixed (FSPs), expressing P-selectin and P-selectin glycoprotein ligand-1 (PSGL-1), restored eosinophil and lymphocyte recruitment. Transfusion with platelets from P-selectin–deficient mice, or with FSPs stimulated in the presence of a blocking anti–P-selectin antibody, were unable to restore pulmonary leukocyte recruitment. Flow cytometric analysis revealed increased expression of CD11b and VLA-4 on leukocytes attached to platelets after allergen exposure, and CD11b expression on leukocytes was suppressed in thrombocytopenic mice but was restored with the transfusion of FSPs, but not FUSPs, a phenomenon concurrent with the formation of platelet–leukocyte complexes. P-selectin expression on the surfaces of platelets is a major requirement for pulmonary eosinophil and lymphocyte recruitment, allowing circulating platelets to bind to and stimulate leukocytes for endothelial attachment.
A cardioprotective role for the endothelial protein C receptor in lipopolysaccharide-induced endotoxemia in the mouse
Authors: Iwaki Takayuki , Cruz Diana T. , Martin J. Andrew , Castellino Francis J.
Published: November 2004

A model of gram-negative lethal endotoxin shock, involving continuous peritoneal infusion of lipopolysaccharide (LPS), has been applied to wild-type (WT) mice and mice with a severe deficiency of endothelial protein C receptor (EPCRδ/δ). The survival of EPCRδ/δ mice was significantly diminished as compared to WT mice after administration of LPS via this route. Heart rates and central blood pressures also were significantly more depressed in EPCRδ/δ mice, indicating that the receptor-based protein C (PC) pathway functions in regulation of hemodynamic properties in the mouse. Further, heart muscle damage was more severe in EPCRδ/δ mice as compared to WT mice after endotoxin administration, as revealed by the more elevated plasma myoglobin levels in EPCRδ/δ mice and by microscopic examination of stained heart sections. Neutrophil infiltration was more pronounced in heart tissue of EPCRδ/δ mice, perhaps in response to the greatly increased expression level of the chemokine, MIP-2, which also significantly more up-regulated in the LPS-treated EPCRδ/δ mouse cohort. In conclusion, a severe deficiency of EPCR adversely affects survival of mice subjected to continuous infusion of endotoxin, via contributions of more responsive hemodynamic and cardiac alterations, thus suggesting that, among its other functions, the PC-based receptor system has a cardioprotective role after acute inflammatory challenge.
Therapy-related acute myeloid leukemia–like MLL rearrangements are induced by etoposide in primary human CD34+ cells and remain stable after clonal expansion
Authors: Libura Jolanta , Slater Diana J. , Felix Carolyn A. , Richardson Christine
Published: November 2004

Rearrangements involving the MLL gene on chromosome band 11q23 are a hallmark of therapy-related acute myeloid leukemias following treatment with topoisomerase II poisons including etoposide. Therapy-related and de novo genomic translocation breakpoints cluster within a well-characterized 8.3-kb fragment of MLL. Repair of etoposide-stabilized DNA topoisomerase II covalent complexes may initiate MLL rearrangements observed in patients. We used a culture system of primary human hematopoietic CD34+ cells and inverse polymerase chain reaction to characterize the spectrum of stable genomic rearrangements promoted by etoposide exposure originating within an MLL translocation hotspot in therapy-related leukemia. Alterations to the region were observed at a readily detectable frequency in etoposide-treated cells. Illegitimate repair events after minimal repair included MLL tandem duplications and translocations, with minor populations of deletions or insertions. In stably repaired cells that proliferated for 10 to 14 days, the significant majority of illegitimate events were MLL tandem duplications, and several deletions, inversions, insertions, and translocations. Thus, etoposide promotes specific rearrangements of MLL consistent with the full spectrum of oncogenic events identified in leukemic samples. Although etoposide-initiated rearrangements are frequent, only a small subset of translocations occurs in cells that proliferate significantly.
Single-cell analysis of the human NK cell response to missing self and its inhibition by HLA class I
Authors: Draghi Monia , Yawata Nobuyo , Gleimer Michael , Yawata Makoto , Valiante Nicholas M. , Parham Peter
Published: November 2004

Natural killer (NK) cells activate quickly in response to pathogens, tumors, and allogeneic hematopoietic cell transplants. Modulating the NK cell response are clonally distributed NK cell receptors that survey cells for change in the expression of major histocompatibility complex (MHC) class I and structurally related ligands. Here the enzyme-linked immunospot (ELISPOT) assay, intracellular cytokine staining (ICS), and short-term culture were used to quantify the response of bulk NK cell populations from human donors to HLA class I–deficient 221 cells and to 221 cells transfected with single HLA class I allotypes. NK cells in cultures containing interleukin-2 (IL-2) or IL-12 exhibited specificities of HLA class I–mediated inhibition that correlated well with those previously defined using NK cell clones in long-term culture and with the frequencies of cells expressing particular inhibitory HLA class I receptors. Culture with IL-12, but not IL-2, gave an increased frequency of cells expressing CD94: NKG2A but no change in killer immunoglobulin-like receptor (KIR) expression. For some heterozygote combinations of KIR3DL1 alleles, ICS can be used to compare the functional properties of the 2 allotypes. Thus, both the low-expressing KIR3DL1*005 and the high-expressing KIR3DL1*002 gave similar inhibitory response on challenge with an HLA-B*5801 ligand. The single-cell assays developed here should facilitate future population study and clinical analysis of human NK cell regulation by MHC class I.
Iron trafficking in the mitochondrion: novel pathways revealed by disease
Authors: Napier Ian , Ponka Prem , Richardson Des R.
Published: November 2004

It is well known that iron (Fe) is transported to the mitochondrion for heme synthesis. However, only recently has the importance of this organelle for many other facets of Fe metabolism become widely appreciated. Indeed, this was stimulated by the description of human disease states that implicate mitochondrial Fe metabolism. In particular, studies assessing various diseases leading to mitochondrial Fe loading have produced intriguing findings. For instance, the disease X-linked sideroblastic anemia with ataxia (XLSA/A) is due to a mutation in the ATP-binding cassette protein B7 (ABCB7) transporter that is thought to transfer [Fe-S] clusters from the mitochondrion to the cytoplasm. This and numerous other findings suggest the mitochondrion is a dynamo of Fe metabolism, being vital not only for heme synthesis but also for playing a critical role in the genesis of [Fe-S] clusters. Studies examining the disease Friedreich ataxia have suggested that a mutation in the gene encoding frataxin leads to mitochondrial Fe loading. Apart from these findings, the recently discovered mitochondrial ferritin that may store Fe in ring sideroblasts could also regulate the level of Fe needed for heme and [Fe-S] cluster synthesis. In this review, we suggest a model of mitochondrial Fe processing that may account for the pathology observed in these disease states.
Blood Ionized Calcium Is Associated with Clustered Polymorphisms in the Carboxyl-Terminal Tail of the Calcium-Sensing Receptor
Authors: Scillitani Alfredo , Guarnieri Vito , De Geronimo Simona , Muscarella Lucia Anna , Battista Claudia , D’Agruma Leonardo , Bertoldo Francesco , Florio Cinzia , Minisola Salvatore , Hendy Geoffrey N. , Cole David E. C.
Published: November 2004

Blood ionized calcium (iCa) is a quantitative trait subject to genetic influence. iCa is maintained in a narrow range through the action of the calcium-sensing receptor (CASR) controlling PTH secretion and calcium excretion. A CASR single nucleotide polymorphism (SNP) prevalent in Caucasian populations (A986S) has shown significant association with iCa in a cohort of young women, but association with the neighboring SNPs, R990G and Q1011E, has not been examined. We studied 377 unrelated adults (184 men and 193 women) recruited as healthy adults from a blood donor clinic. The subjects were not taking any medications, nor did they have disorders of calcium metabolism. Relative frequencies for the CASR 986S, 990G, and 1011E minor alleles were 24%, 4%, and 3% respectively. At the A986S locus, subjects with the AA genotype had significantly lower iCa (P = 0.0001) than subjects with one or two S alleles (mean ± se, 1.221 ± 0.003 vs. 1.239 ± 0.003 mmol/liter). For the R990G site, subjects with the RR genotype had higher iCa than those with one copy of the 990G allele (1.230 ± 0.002 vs. 1.213 ± 0.007 mmol/liter; P = 0.032). With respect to the 1011 locus, iCa was lower in QQ genotype subjects than in the QE group (1.227 ± 0.002 vs. 1.255 ± 0.008 mmol/liter; P = 0.002). After resolution of phase for the doubly heterozygous subjects, analysis was conducted on haplotypes across all three loci. As expected, subjects with SRQ and ARE haplotypes are relatively hypercalcemic, and those with AGQ are hypocalcemic, relative to subjects with the common ARQ haplotype. Multiple regression analysis with clinical covariates (age, sex and menopausal status, creatinine, and PTH) showed that 16.5% of the total variance in iCa may be explained, and the seven CASR haplotypes contribute significantly (P < 0.0001) and substantially (49.1% of the explained variance) to the model, with the following corrected iCa means: ARQ/AGQ, 1.21 ± 0.01; ARQ/ARQ, 1.22 ± 0.01; ARQ/SRQ, 1.24 ± 0.01; SRQ/AGQ, 1.24 ± 0.03; SRQ/SRQ, 1.25 ± 0.01; ARQ/ARE, 1.25 ± 0.01; and SRQ/ARE, 1.27 ± 0.01. Our data confirm the association between iCa and the A986S locus and suggest that R990G and Q1011E are also predictive. Given the significant between-population variations in frequency of variant alleles in this CASR SNP cluster, tri-locus haplotyping may prove to be more informative in studies of association between variation in CASR and disease.
Late Life Metabolic Syndrome, Early Growth, and Common Polymorphism in the Growth Hormone and Placental Lactogen Gene Cluster
Authors: Day Ian N. M. , Chen Xiao-he , Gaunt Tom R. , King Tabitha H. T. , Voropanov Anca , Ye Shu , Rodriguez Santiago , Syddall Holly E. , Sayer Avan Aihie , Dennison Elaine M. , Tabassum Faiza , Barker David J. P. , Cooper Cyrus , Phillips David I. W.
Published: November 2004

Low rates of fetal and infant growth are associated with the metabolic syndrome and cardiovascular disease in later life. We investigated common genetic variation in the GH-CSH gene cluster on chromosome 17q23 encoding GH, placental lactogens [chorionic somatomammotropins (CSH)], and placental GH variant in relation to fetal and infant growth and phenotypic features of the metabolic syndrome in subjects aged 59–72 yr from Hertfordshire, UK. Allele groups T, D1, and D2 of a locus herein designated CSH1.01 were examined in relation to GH-CSH single nucleotide polymorphisms and to specific phenotypes. Average birth weights were similar for all genotype groups. Men with T alleles were significantly lighter at 1 yr of age, shorter as adults, and had higher blood pressures, fasting insulin (T/T 66% higher than D2/D2) and triglyceride concentrations, and insulin and glucose concentrations during a glucose tolerance test. Birth weight and 1-yr weight associations with metabolic syndrome traits were independent of the CSH1.01 effects. Common diversity in GH-CSH correlates with low 1-yr weight and with features of the metabolic syndrome in later life. GH-CSH genotype adds substantially to, but does not account for, the associations between low body weight, at birth and in infancy, and the metabolic syndrome.
Tissue Factor and CCL2/Monocyte Chemoattractant Protein-1 Released by Human Islets Affect Islet Engraftment in Type 1 Diabetic Recipients
Authors: Bertuzzi Federico , Marzorati Simona , Maffi Paola , Piemonti Lorenzo , Melzi Raffaella , de Taddeo Francesca , Valtolina Veronica , D’Angelo Armando , di Carlo Valerio , Bonifacio Ezio , Secchi Antonio
Published: November 2004

Islet survival in the early posttransplantation period is likely to be influenced by inflammatory events in and around islets. Twenty-seven human islet preparations were transplanted by 24 infusions into 14 patients with brittle type 1 diabetes under the Edmonton protocol. Patients were monitored for their coagulation [cross-linked fibrin degradation products (XDPs)] and liver function test [aspartate and alanine aminotransferase (AST and ALT)] as markers of early posttransplant complications, and these were correlated with in vitro islet number, purification, volume, monocyte-chemoattractant protein-1 (CCL2/MCP-1) and tissue factor (TF) islet release. Consistent with activation of coagulation pathways and hepatic damage, serum XDP values increased early after 11 infusions and transaminase after 13 of 24 infusions. TF and CCL2/MCP-1 were detected in supernatants of 21 and 22 islet preparations, respectively. Serum XDP peak values were correlated with TF/equivalent islets (EI) (r2=0.26, P = 0.001) and CCL2/MCP-1/EI (r2 = 0.42; P < 0.001); serum transaminase areas under the curve in the first week posttransplantation were correlated with CCL2/MCP-1/EI (r2 = 0.55; P < 0.001 for ALT and r2 = 0.51; P = 0.001 for AST) and TF/EI (r2 = 0.31; P = 0.002 for ALT, and r2 = 0.36; P = 0.002 for AST). These data suggest that reducing the islet proinflammatory state may be a means to reduce the early posttransplant complications and perhaps improve islet engraftment.
Expression and Deoxyribonucleic Acid-Binding Activity of the Nuclear Factor κB Family in the Human Myometrium during Pregnancy and Labor
Authors: Chapman Neil R. , Europe-Finner G. Nicholas , Robson Stephen C.
Published: November 2004

In humans, the factors that govern the switch from myometrial quiescence to coordinated contractions at the initiation of labor are not well defined. The onset of parturition is itself associated with increases in a number of proinflammatory factors, many of which are regulated by the nuclear factor κB (NF-κB) family of transcription factors. The expression and DNA-binding activity of NF-κB in the myometrium during gestation and parturition were examined. Levels of c-Rel, p50, and p105 NF-κB species were dramatically reduced in pregnant myometrium compared with nonpregnant (NP) controls, whereas expression of the RelA subunit remained uniform. Importantly, during labor, expression of all subunits was observed to be significantly reduced in all myometrial samples studied relative to NP levels. Moreover, for RelA, c-Rel, and p50 subunits, there was a gradient of expression between laboring upper (corpus) and lower uterine segment myometrium. No RelB or p52 subunits could be detected. EMSAs identified changes in NF-κB subunit composition in the myometrium during pregnancy and labor, with p50 homodimers predominant in NP tissues being replaced with RelA:p50 heterodimers in pregnant and laboring samples. Significantly, RelA was observed to be phosphorylated at serine-536, implicating the involvement of the phosphatidylinositol-3-kinase/AKT pathway in NF-κB function in the myometrium.
Ligand- and Cell-Specific Effects of Signal Transduction Pathway Inhibitors on Progestin-Induced Vascular Endothelial Growth Factor Levels in Human Breast Cancer Cells
Authors: Wu Jianbo , Brandt Sandra , Hyder Salman M.
Published: November 2004

We evaluated the signaling pathways involved in regulating vascular endothelial growth factor (VEGF), a potent angiogenic growth factor, in response to natural and synthetic progestins in breast cancer cells. Inhibition of the phosphoinositide-3′-kinase (PI3-kinase) signaling pathway or the specificity protein-1 (SP-1) transcription factor abolished both progesterone- and medroxyprogesterone acetate (MPA)-induced VEGF secretion from BT-474 and T47-DCO cells. Inhibitors of the MAPK kinase 1/2/MAPK and N-terminal jun kinase/MAPK signaling pathways blocked both progesterone- and MPA-induced VEGF secretion in BT-474 cells. However, these inhibitors blocked only progesterone-, but not MPA-induced VEGF secretion in T47-DCO cells. Inhibitors of PI3-kinase or SP-1 blocked both progesterone- and MPA-induced increases in VEGF mRNA levels in T47-DCO cells. The proximal SP-1 sites within the VEGF promoter were critical for progestin-dependent induction of VEGF. In contrast, MAPK inhibitors did not block the progesterone- or MPA-induced increases in VEGF mRNA in T47-DCO cells, suggesting that MAPK inhibitors decreased progesterone-induced VEGF secretion in T47-DCO cells by blocking posttranscriptional mechanisms. The MAPK kinase/ERK/MAPK-independent induction of VEGF mediated by MPA was associated with the PRB [progesterone receptor (PR) B] isoform of the PR in T47-DCO cells. None of the inhibitors tested reduced basal PR levels or abrogated PR-dependent gene expression from a reporter plasmid, indicating that loss of PR function cannot explain any of the observed effects. Because the PI3-kinase signaling pathway and SP-1 transcription factor play critical roles in progestin-dependent VEGF induction, these may be useful targets for developing antiangiogenic therapies to prevent progression of progestin-dependent human breast cancers.
The Src Kinase Pathway Promotes Tamoxifen Agonist Action in Ishikawa Endometrial Cells through Phosphorylation-Dependent Stabilization of Estrogen Receptor α Promoter Interaction and Elevated Steroid Receptor Coactivator 1 Activity
Authors: Shah Yatrik M. , Rowan Brian G.
Published: November 2004

Tamoxifen is the most widely used selective estrogen receptor modulator for breast cancer in clinical use today. However, tamoxifen agonist action in endometrium remains a major hurdle for tamoxifen therapy. Activation of the nonreceptor tyrosine kinase src promotes tamoxifen agonist action, although the mechanisms remain unclear. To examine these mechanisms, the effect of src kinase on estrogen and tamoxifen signaling in tamoxifen-resistant Ishikawa endometrial adenocarcinoma cells was assessed. A novel connection was identified between src kinase and serine 167 phosphorylation in estrogen receptor (ER)-α via activation of AKT kinase. Serine 167 phosphorylation stabilized ER interaction with endogenous ER-dependent promoters. Src kinase exhibited the additional function of potentiating the transcriptional activity of Gal-steroid receptor coactivator 1 (SRC-1) and Gal-cAMP response element binding protein-binding protein in endometrial cancer cells while having no effect on Gal-p300-associated factor and Gal fusions of the other p160 coactivators glucocorticoid-interacting protein 1 (transcriptional intermediary factor 2/nuclear coactivator-2/SRC-2) and amplified in breast cancer 1 (receptor-associated coactivator 3/activator of transcription of nuclear receptor/SRC-3). Src effects on ER phosphorylation and SRC-1 activity both contributed to tamoxifen agonist action on ER-dependent gene expression in Ishikawa cells. Taken together, these data demonstrate that src kinase potentiates tamoxifen agonist action through serine 167-dependent stabilization of ER promoter interaction and through elevation of SRC-1 and cAMP response element binding protein-binding protein coactivation of ER.
Interaction between Insulin-Like Growth Factor-I Receptor and αVβ3 Integrin Linked Signaling Pathways: Cellular Responses to Changes in Multiple Signaling Inputs
Authors: Clemmons D. R. , Maile L. A.
Published: November 2004

Integrins are heterodimeric transmembrane proteins that mediate cell attachment to extracellular matrix, migration, division, and inhibition of apoptosis. Because growth factors are also important for these processes, there has been interest in cooperative signaling between growth factor receptors and integrins. IGF-I is an important growth factor for vascular cells. One integrin, αVβ3, that is expressed in smooth muscle cells modulates IGF-I actions. Ligand occupancy of αVβ3 is required for IGF-I to stimulate cell migration and division. Src homology 2 containing tyrosine phosphatase (SHP-2) is a tyrosine phosphatase whose recruitment to signaling molecules is stimulated by growth factors including IGF-I. If αVβ3 ligand occupancy is inhibited, there is no recruitment of SHP-2 to αVβ3 and its transfer to downstream signaling molecules is blocked. Ligand occupancy of αVβ3 stimulates tyrosine phosphorylation of the β3-subunit, resulting in recruitment of SHP-2. This transfer is mediated by an insulin receptor substrate-1-related protein termed DOK-1. Subsequently, SHP-2 is transferred to another transmembrane protein, SHPS-1. This transfer requires IGF-I receptor-mediated tyrosine phosphorylation of SHPS-1, which contains two YXXL motifs that mediate SHP-2 binding. The transfer of SHP-2 to SHPS-1 is also required for recruitment of Shc to SHPS-1. Ligand occupancy of αVβ3 results in sustained Shc phosphorylation and enhanced Shc recruitment. Shc activation results in induction of MAPK. Inhibition of the Shc/SHPS-1 complex formation results in failure to achieve sustained MAPK activation and an attenuated mitogenic response. Thus, within the vessel wall, a mechanism exists whereby ligand occupancy of the αVβ3 integrin is required for assembly of a multicomponent membrane signaling complex that is necessary for cells to respond optimally to IGF-I.
The biodynamics of arboreal locomotion: the effects of substrate diameter on locomotor kinetics in the gray short-tailed opossum (Monodelphis domestica)
Authors: Lammers Andrew R. , Biknevicius Audrone R.
Published: November 2004

Effects of substrate diameter on locomotor biodynamics were studied in the gray short-tailed opossum (Monodelphis domestica). Two horizontal substrates were used: a flat `terrestrial' trackway with a force platform integrated into the surface and a cylindrical `arboreal' trackway (20.3 mm diameter) with a force-transducer instrumented region. On both terrestrial and arboreal substrates, fore limbs exhibited higher vertical impulse and peak vertical force than hind limbs. Although vertical limb impulses were lower on the terrestrial substrate than on the arboreal support, this was probably due to speed effects because the opossums refused to move as quickly on the arboreal trackway. Vertical impulse decreased significantly faster with speed on the arboreal substrate because most of these trials were relatively slow,and stance duration decreased with speed more rapidly at these lower speeds. While braking and propulsive roles were more segregated between limbs on the terrestrial trackway, fore limbs were dominant both in braking and in propulsion on the arboreal trackway. Both fore and hind limbs exerted equivalently strong, medially directed limb forces on the arboreal trackway and laterally directed limb forces on the terrestrial trackway. We propose that the modifications in substrate reaction force on the arboreal trackway are due to the differential placement of the limbs about the dorsolateral aspect of the branch. Specifically, the pes typically made contact with the branch lower and more laterally than the manus, which may explain the significantly lower required coefficient of friction in the fore limbs relative to the hind limbs.
Temperature and the expression of myogenic regulatory factors (MRFs) and myosin heavy chain isoforms during embryogenesis in the common carpCyprinus carpioL.
Authors: Cole Nicholas J. , Hall Thomas E. , Martin Christopher I. , Chapman Mark A. , Kobiyama Atsushi , Nihei Yoshiaki , Watabe Shugo , Johnston Ian A.
Published: November 2004

Embryos of the common carp, Cyprinus carpio L., were reared from fertilization of the eggs to inflation of the swim bladder in the larval stage at 18 and 25°C. cRNA probes were used to detect transcripts of the myogenic regulatory factors MyoD, Myf-5 and myogenin, and five myosin heavy chain (MyHC) isoforms during development. The genes encoding Myf-5 and MyoD were switched on first in the unsegmented mesoderm, followed by myogenin as the somites developed. Myf-5 and MyoD transcripts were initially limited to the adaxial cells, but Myf-5 expression spread laterally into the presomitic mesoderm before somite formation. Two distinct bands of staining could be seen corresponding to the cellular fields of the forming somites, but as each furrow delineated, Myf-5 mRNA levels declined. Upon somite formation, MyoD expression spread laterally to encompass the full somite width. Expression of the myogenin gene was also switched on during somite formation, and expression of both transcripts persisted until the somites became chevron-shaped. Expression of MyoDwas then downregulated shortly before myogenin. The expression patterns of the carp myogenic regulatory factor (MRF) genes most-closely resembled that seen in the zebrafish rather than the rainbow trout (where expression of MyoD remains restricted to the adaxial domain of the somite for a prolonged period) or the herring (where expression of MyoD persists longer than that of myogenin). Expression of two embryonic forms of MyHC began simultaneously at the 25-30 somite stage and continued until approximately two weeks post-hatch. However, the three adult isoforms of fast muscle MyHC were not detected in any stage examined, emphasizing a developmental gap that must be filled by other, as yet uncharacterised, MyHC isoform(s). No differences in the timing of expression of any mRNA transcripts were seen between temperature groups. A phylogenetic analysis of the MRFs was conducted using all available full-length amino acid sequences. A neighbour-joining tree indicated that all four members evolved from a common ancestral gene, which first duplicated into two lineages, each of which underwent a further duplication to produce Myf-5 and MyoD, and myogenin and MRF4. Parologous copies of MyoD from trout and Xenopus clustered closely together within clades, indicating recent duplications. By contrast, MyoDparalogues from gilthead seabream were more divergent, indicating a more-ancient duplication.