bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression of lactate dehydrogenase A and B genes in different tissues of rats adapted to chronic hypobaric hypoxia
Authors: Rossignol Fabrice , Solares Magali , Balanza Elfride , Coudert Jean , Clottes Eric 
Published: April 2003

AbstractLactate dehydrogenase (LDH) is a tetramer made up of two different subunits A and B. In cellular models, severe hypoxia increases LDH A gene expression whereas LDH B gene does not exhibit any regulation. The aim of our work was to characterise LDH expression in different tissues of rats bred at high altitude. For this purpose, we chose a Sprague–Dawley rat strain adapted to chronic hypoxia in La Paz (3700 m), Bolivia. Two normoxic control groups were bred at low altitude in Clermont‐Ferrand (350 m), France, one group was ad libitum with free access to food and water as was the hypoxic one, and the second normoxic group was nourished with the food intakes measured for the animals from La Paz. We measured total LDH specific activity, isoform distribution and LDH A and B mRNA amounts in three skeletal muscles (soleus, extensor digitorum longus (EDL), plantaris), heart and brain. Our study demonstrates that, unlike what has been shown in cellular models under severe hypoxia, LDH A gene is not systematically up‐regulated in tissues of rats living at high altitude. Furthermore, chronic hypoxia limits LDH B gene transcription or its mRNA stability in both soleus and EDL. These regulations occur at various molecular levels like gene transcription, mRNA stabilisation or translation and protein stability, depending on the tissue studied, and are partly attributed to caloric restriction provoked by high altitude. These data provide insight into LDH gene expression underlying the diverse and complex tissue‐specific response to chronic hypoxia. J. Cell. Biochem. 89: 67–79, 2003. © 2003 Wiley‐Liss, Inc.
Mesangial cells are able to produce catecholamines in vitro
Authors: Di Marco Giovana Seno , Naffah‐Mazzacoratti Maria da Graça , Vio Carlos P. , Dos Santos Oscar Fernando Pavão , Schor Nestor , Casarini Dulce Elena 
Published: April 2003

AbstractMesangial cells (MC) participate in the control of the glomerular function due to their ability to synthesize hormones and induce cell contraction. Since MC can produce various kinds of hormones, the purpose of the present study was to determine if they are able to synthesize catecholamines. For this evaluation, the levels of norepinephrine, epinephrine, dopamine, and biopterin, the enzymatic cofactor of tyrosine hydroxylase (TH), were analyzed by HPLC in the intracellular compartment and in the medium of primary cultured MC. To identify and locate the enzymes responsible for monoamine synthesis, TH, dopa decarboxylase, and dopamine β‐hydroxylase, Western blotting and immunocytochemistry were employed using monoclonal and polyclonal antibodies. Concentrations of NE = 57 ± 8, EPI = 82 ± 10, and DA = 52 ± 9 pg/mg protein (X ± SEM) were found in the cell homogenate. The culture medium showed concentrations of NE = 25 ± 3, EPI = 33 ± 3, and DA = 62 ± 15 pg/mg protein. Western blotting analysis and immunocytochemistry evidenced the presence of all enzymes. Moreover, biopterin was also detected in the intracellular compartment and in the medium (0.28 ± 0.03 and 5.70 ± 2 nmol/mg cell protein, respectively). Overall, the data indicate that MC have the biosynthetic machinery necessary to produce catecholamines, suggesting that they can act as a paracrine/autocrine hormone system, contributing to the regulation of glomerular hemodynamic and renal microcirculation. J. Cell. Biochem. 89: 144–151, 2003. © 2003 Wiley‐Liss, Inc.
Estrogen receptor‐β modulates synthesis of bone matrix proteins in human osteoblast‐like MG63 cells
Authors: Cao Lihuan , Bu Rongfa , Oakley Jennifer I. , Kalla Sara E. , Blair Harry C. 
Published: April 2003

AbstractEstrogens have complex effects on the skeleton, including regulation of modeling and maintenance of bone mass, which vary with cell type and developmental stage. Osteoblasts are key regulators of skeletal matrix synthesis and degradation. However, whether osteocytes, osteoblasts or earlier progenitors mediate estrogen effects, and the importance of estrogen receptors (ERs) α and β, remain unclear. To address estrogen response in human cells closely related to secretory osteoblasts, we studied MG63 cells with ERα or ERβ reduced to low levels by stable transfection of antisense plasmids. Collagen and alkaline phosphatase expression increased with estrogen in wild‐type and ERα‐suppressed cells, but not in ERβ‐suppressed cells. Matrix secretion occurs as osteoblasts cease dividing, and, in keeping with this, cell proliferation was reduced by estrogen except in ERβ‐antisense cells. No effects of estrogen on wild type or ER‐suppressed cells were seen in expression of BMP 2, the BMP antagonist noggin, or Indian hedgehog, products that regulate differentiation of osteoblasts. In contrast to expectations that estrogen would modulate bone degradation, RANKL, CSF‐1, and osteoprotegerin did not respond measurably to estrogen, regardless of ER status. In keeping with this result, estrogen response was not observed in assays of osteoclast development from CD14 cells supported by wild‐type or ER‐silenced MG63 cells. Since estrogens are major regulators of bone degradation in vivo, estrogen effects on osteoclasts may depend on interaction with stimuli present in bone but absent in the model studied. cDNA hybridization showed that additional estrogen‐binding proteins including ERRα and BCAR3 were expressed by MG63, but estrogen effects in ERβ‐silenced cells were small, so these proteins are either minor regulators in MG63 cells, or act in concert with stimuli in addition to estrogen. We conclude that, in the MG63 cell line, estrogen increases synthesis of matrix proteins via ERβ, and that, in the absence of additional stimuli, these cells are not major mediators of estrogen effects on osteoclast differentiation. Further, ERα is probably much more important in earlier stages of skeletal development, such as growth plate response, than in osteoblasts. J. Cell. Biochem. 89: 152–164, 2003. © 2003 Wiley‐Liss, Inc.
BRCA1 splice variants exhibit overlapping and distinct transcriptional transactivation activities
Authors: McEachern Kristen A. , Archey William B. , Douville Karen , Arrick Bradley A. 
Published: April 2003

AbstractThe global changes in gene expression induced by transient increased expression of full length BRCA1 as well as the spliced variant BRCA1S were evaluated by cDNA expression array in a human non‐tumorigenic mammary epithelial cell line, MCF10A. Over 30 genes were identified that displayed an altered expression pattern in response to the expression of BRCA1 splice variants. The expression of NFκB inducing kinase was markedly down‐regulated in BRCA1L transfected cells. However, a NFκB‐responsive promoter construct yielded increased basal activity in BRCA1L transfected cells, as well as following treatment with tumor necrosis factor‐α or lymphotoxin. In addition, nuclear extracts from BRCA1L transfected cells displayed increased DNA binding to the κB consensus site. The transcriptional activity of a panel of promoter constructs was evaluated following expression of wild type or mutant BRCA1. Full length BRCA1 transactivated the estrogen receptor‐α (ERα) and BCL2 promoters as well as AP‐1, SRE, and CRE containing promoters. Transactivation activity of the exon 11‐deleted BRCA1S was more limited and usually of lower magnitude. The ability of a pathogenic mutation, 5382insC, to abrogate the transcriptional transactivation by BRCA1L and BRCA1S was also investigated. Mutant BRCA1 retained wild type levels of transcriptional activity for the ERα promoter as well as for the NFκB, AP‐1, and CRE‐responsive promoters but had reduced or no activity with the BCL2 and SRE promoters. These results show that BRCA1 isoforms have both overlapping and distinct transcriptional transactivation activity, and that a mutant form of BRCA1 implicated in carcinogenesis is not devoid of all activity. J. Cell. Biochem. 89: 120–132, 2003. © 2003 Wiley‐Liss, Inc.
AIDS‐related Kaposi's sarcoma cells rapidly internalize endostatin, which co‐localizes to tropomysin microfilaments and inhibits cytokine‐mediated migration and invasion
Authors: Mallery Susan R. , Morse Mark A. , Wilson Ralph F. , Pei Ping , Ness Gregory M. , Bradburn Jennifer E. , Renner Robert J. , Schuller David E. , Robertson Fredika M. 
Published: April 2003

AbstractAIDS‐related Kaposi's sarcoma (KS) is the most common HIV‐related malignancy. In some respects, KS is analogous to other angioproliferative diseases, in that KS lesions are highly vascularized and promoted by inflammatory cytokines. However, unlike other cancers or inflammatory mediated vascular diseases, KS is unique in that the KS lesional cells both express and respond to the complete angiogenic cytokines vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). Therefore, the angiogenic phenotype, which is crucial for cancer progression, is inherent to KS tumor cells. Due to the recognized importance of angiogenesis in cancer progression, numerous angiostatic agents are being investigated as potential therapeutic agents. One such agent is endostatin, which is a 20‐kDa carboxyl‐terminal fragment of collagen XVIII that has demonstrated potent angiostatic activities at both the in vivo and in vitro levels. Since endostatin is recognized as a potent angiostatic agent, the majority of in vitro endostatin studies have evaluated its effects on endothelial cells. Although KS cells are speculated to arise from endothelial cell precursors and KS lesions are highly vascularized, no previous studies have investigated endostatin–KS cell interactions. This present study evaluated endostatin's effects on KS tumor cell: (i) signal transduction (endostatin internalization and transcription factor activation), and (ii) migration and invasion (functional activity assays and tropomysin co‐localization). Our results show that KS cells rapidly internalize endostatin and that endostatin initiates activation of the transcription activating factors nuclear factor‐κB (NF‐κB) and activating protein 1 (AP‐1). Our data also show that internalized endostatin co‐localizes to tropomysin microfilaments and acts to inhibit KS cell migration and invasion in response to the clinically relevant angiogenic cytokines VEGF and bFGF. As a consequence of its combined angiostatic and antitumorigenic activities, endostatin could provide dual therapeutic benefits for patients with mucocutaneous KS. J. Cell. Biochem. 89: 133–143, 2003. Published 2003 Wiley‐Liss, Inc.
Mediators of the biphasic responses of bone to intermittent and continuously administered parathyroid hormone
Authors: Locklin Rachel M. , Khosla Sundeep , Turner Russell T. , Riggs B. Lawrence 
Published: April 2003

AbstractParathyroid hormone (PTH) has biphasic effects on bone: continuous treatment is catabolic whereas intermittent treatment is anabolic. The mechanism(s) responsible for these differing effects are still unclear, partly because of the previous non‐availability of a model system in which effects on both formation and resorption indices could be studied concomitantly. In cultured marrow cells from 6‐week old C57BL/6 mice, we demonstrated that 4 days of intermittent PTH treatment increased mRNA for osteoblast differentiation markers (Runx2, alkaline phosphatase (AP), and type I procollagen (COL1A1) whereas continuous treatment resulted in production of large numbers of TRAP‐positive multinucleated osteoclasts. Although IGF‐I mRNA did not increase after intermittent treatment, it was consistently higher than after continuous treatment, and the addition of an anti‐IGF‐I neutralizing antibody prevented the increase in bone formation indices observed with intermittent treatment. By contrast, after continuous treatment, gene expression of RANK ligand (RANKL) was increased and that of osteoprotegerin (OPG) was decreased, resulting in a 25‐fold increase in the RANKL/OPG ratio. In this model system, the data suggest that intermittent PTH treatment enhances osteoblast differentiation through an IGF‐I dependent mechanism and continuous PTH treatment enhances osteoclastogenesis through reciprocal increases in RANKL and decreases in OPG. J. Cell. Biochem. 89: 180–190, 2003. © 2003 Wiley‐Liss, Inc.
Upstream and downstream targets of RUNX proteins
Authors: Otto Florian , Lübbert Michael , Stock Michael 
Published: April 2003

AbstractIn recent years, the in vivo role of the three members of the RUNX family of transcription factors has in part been elucidated. While Runx1 is essential for mature haematopoiesis and Runx2 for osteochondrogenesis, Runx3 has a function in the nervous system. Translocations and mutations affecting the RUNX1 gene are clearly implicated in leukemogenesis whereas recent data suggest that changed expression levels of RUNX3 may be involved in gastric carcinogenesis. Germ line mutations in RUNX2 have been identified in patients with an autosomal dominant skeletal disorder, cleidocranial dysplasia. While a number of pathways have been delineated that regulate RUNX activity, transcription factors binding to RUNX promoters are only beginning to be identified. A growing number of genes have been characterised that are being regulated in their transcriptional activity by different RUNX proteins. Whether a particular RUNX protein specifically targets a defined subset of downstream genes or whether there is some redundancy as to which RUNX protein activates which target promoter remains to be elucidated. J. Cell. Biochem. 89: 9–18, 2003. © 2003 Wiley‐Liss, Inc.
Modulation of PPARγ activity with pharmaceutical agents: Treatment of insulin resistance and atherosclerosis
Authors: Wang Minghan , Tafuri Sherrie 
Published: April 2003

AbstractThe anti‐diabetic thiazolidinediones (TZDs) are a class of compounds with insulin‐sensitizing activity that were originally discovered using in vivo pharmacological screens. In subsequent binding studies, TZDs were demonstrated to enhance insulin action by activating peroxisome proliferator‐activated receptor gamma (PPARγ). PPARγ is a member of the ligand‐activated nuclear receptor superfamily that promotes adipogenesis and enhances insulin sensitivity by controlling the expression of genes in glucose and lipid metabolism. Given the large size of the ligand binding pocket in PPARγ, novel classes of both full and partial agonists that are structurally distinct from TZDs have been discovered. These compounds have been effective tools in differentiating adipogenic and insulin‐sensitizing activities as well as tissue selectivity of PPARγ activation. This information has led to the hypothesis that one ligand can activate or inactivate PPARs depending upon the tissue in which the PPAR resides. Thus particular compounds can be designated selective PPAR modulators or SPPARMs, a concept similar to that observed with the activation of estrogen receptor (ER) by SERMS. Additionally, both preclinical and clinical data suggest that PPARγ activation is useful for the prevention of atherosclerosis. However, the effects of TZDs on plasma lipid profiles do not solely account for their anti‐atherogenic effects. Recent studies with macrophage cells and animal models for atherosclerosis indicate that TZDs reduce the size and number of lesions formed in the vessel wall by modulating foam cell formation and inflammatory responses by macrophages. Thus in addition to the treatment of type II diabetes, PPARγ agonists can be potentially employed for the treatment of atherosclerosis in general population. J. Cell. Biochem. 89: 38–47, 2003. © 2003 Wiley‐Liss, Inc.
Inhibition of cell survival signal protein kinase B/Akt by curcumin in human prostate cancer cells
Authors: Chaudhary Lala R. , Hruska Keith A. 
Published: April 2003

AbstractAlthough curcumin has been shown to inhibit prostate tumor growth in animal models, its mechanism of action is not clear. To better understand the anti‐cancer effects of curcumin, we investigated the effects of curcumin on cell survival factor Akt in human prostate cancer cell lines, LNCaP, PC‐3, and DU‐145. Our results demonstrated differential activation of Akt. Akt was constitutively activated in LNCaP and PC‐3 cells. Curcumin inhibited completely Akt activation in both LNCaP and PC‐3 cells. The presence of 10% serum decreased the inhibitory effect of curcumin in PC‐3 cells whereas complete inhibition was observed in 0.5% serum. Very little or no activation of Akt was observed in serum starved DU‐145 cells (0.5% serum). The presence of 10% serum activated Akt in DU‐145 cells and was not inhibited by curcumin. Results suggest that one of the mechanisms of curcumin inhibition of prostate cancer may be via inhibition of Akt. To our knowledge this is the first report on the curcumin inhibition of Akt activation in LNCaP and PC‐3 but not in DU‐145 cells. J. Cell. Biochem. 89: 1–5, 2003. © 2003 Wiley‐Liss, Inc.
Role of Pin2/TRF1 in telomere maintenance and cell cycle control
Authors: Zhou Xiao Zhen , Perrem Kilian , Lu Kun Ping 
Published: April 2003

AbstractTelomeres are specialized structures found at the extreme ends of chromosomes, which have many functions, including preserving genomic stability, maintaining cell proliferative capacity, and blocking the activation of DNA‐damage cell cycle checkpoints. Deregulation of telomere length has been implicated in cancer and ageing. Telomere maintenance is tightly regulated by telomerase and many other telomere‐associated proteins and is also closely linked to cell cycle control, especially mitotic regulation. However, little is known about the identity and function of the signaling molecules connecting telomere maintenance and cell cycle control. Pin2/TRF1 was originally identified as a protein bound to telomeric DNA (TRF1) and as a protein involved in mitotic regulation (Pin2). Pin2/TRF1 negatively regulates telomere length and importantly, its function is tightly regulated during the cell cycle, acting as an important regulator of mitosis. Recent identification of many Pin2/TRF1 upstream regulators and downstream targets has provided important clues to understanding the dual roles of Pin2/TRF1 in telomere maintenance and cell cycle control. These results have led us to propose that Pin2/TRF1 functions as a key molecule in connecting telomere maintenance and cell cycle control. J. Cell. Biochem. 89: 19–37, 2003. © 2003 Wiley‐Liss, Inc.
Sequence requirement for nuclear localization and growth inhibition of p27Kip1R, a degradation‐resistant isoform of p27Kip1
Authors: Hirano Katsuya , Zeng Ying , Hirano Mayumi , Nishimura Junji , Kanaide Hideo 
Published: April 2003

Abstractp27Kip1R is an isoform of p27Kip1, having a distinct C‐terminus. The sequences of p27Kip1R required for nuclear localization and growth inhibition were determined in HeLa cells using a green fluorescence protein (GFP) as a reporter molecule. Region 153–168 and residues K168 and I169 were determined to play a critical role in the nuclear localization of p27Kip1R. Aliphatic amino acid was found to be a substitute for the basic residue in the typical nuclear localization signal, while its functional substitution was incomplete, thereby causing a significant cytoplasmic retention of p27Kip1R. p27Kip1R is thus the first example of an atypical bipartite nuclear localization signal with aliphatic amino acid as a functional residue. Despite cytoplasmic retention, p27Kip1R inhibited the cell growth as well as p27Kip1, while GFP alone had no effect. The mutants lacking an N‐terminus containing the binding regions for cyclins and cyclin‐dependent kinases also showed a significant degree of nuclear localization, but failed to inhibit cell growth. The growth inhibition by p27Kip1R as well as p27Kip1 was thus suggested to originate in the common N‐terminal region. J. Cell. Biochem. 89: 191–202, 2003. © 2003 Wiley‐Liss, Inc.
Induction of cellular necrosis by the glutathione peroxidase mimetic ebselen
Authors: Guérin Paul J. , Gauthier Eric R. 
Published: April 2003

AbstractThe selenium‐based compound ebselen is a powerful antioxidant, a potent anti‐inflammatory agent and a potential neuroprotective compound. Several studies have demonstrated that part of the biological effect of ebselen is the result of the inhibition of apoptosis. We show in this report that ebselen induced the necrotic cell death of Sp2/0‐Ag14 hybridoma cells. This process was rapid, with over 90% of the cells being dead after a 2 h exposure to 50 μM ebselen. The toxic effect of ebselen could not be prevented by the caspase inhibitor Z‐VAD‐fmk but could be blocked with thiol‐containing compounds. Interestingly, ebselen addition completely prevented caspase activation in cycloheximide‐treated Sp2/O‐Ag14 cells, indicating that this antioxidant interferes with the apoptotic machinery. Our results indicate that some cell types are acutely sensitive to the toxic effect of ebselen, and that ebselen‐induced cell death interferes with apoptotic processes. These observations are of particular importance since ebselen is currently used in clinical trials for possible use as therapeutic agent for stroke. J. Cell. Biochem. 89: 203–211, 2003. © 2003 Wiley‐Liss, Inc.
Phosphatidylinositol 3‐kinase coordinately activates the MEK/ERK and AKT/NFκB pathways to maintain osteoclast survival
Authors: Gingery Anne , Bradley Elizabeth , Shaw Aubie , Oursler Merry Jo 
Published: April 2003

AbstractWe have examined highly purified osteoclasts that were generated in vitro from murine co‐culture of marrow precursors with stromal support cells and have found evidence of activation of the MEK/ERK and AKT/NFκB survival pathways. Many mature marrow‐derived osteoclasts survived for at least 48 h in culture whether or not they are maintained with stromal cells. Moreover, supplementing purified osteoclasts with RANKL and/or M‐CSF had no impact on their survival pattern. In addition, spleen‐derived osteoclasts generated with RANKL and M‐CSF treatment exhibited a similar survival pattern. Blocking MEK, AKT, or NFκB activity resulted in apoptosis of many, but not all, of the osteoclasts in purified marrow‐derived osteoclasts, marrow‐derived osteoclasts co‐cultured with stromal cells, and spleen‐derived osteoclasts maintained with RANKL and M‐CSF. These data support that both the MEK/ERK and AKT/NFκB pathways contribute to osteoclast survival. Since PI3K has been shown to activate either of these pathways, we have examined its role in osteoclast survival. PI3K inhibition caused apoptosis of nearly all osteoclasts in purified and co‐cultured marrow‐derived osteoclasts and spleen‐derived osteoclasts maintained with RANKL and M‐CSF. Interestingly, in marrow‐derived co‐cultures, the apoptotic response was restricted to osteoclasts as there was no evidence of stromal support cell apoptosis. PI3K inhibition also blocked MEK1/2, ERK1/2, and AKT phosphorylation and NFκB activation in purified osteoclasts. Simultaneous blockage of both AKT and MEK1/2 caused rapid apoptosis of nearly all osteoclasts, mimicking the response to PI3K inhibition. These data reveal that PI3K coordinately activates two distinct survival pathways that are both important in osteoclast survival. J. Cell. Biochem. 89: 165–179, 2003. © 2003 Wiley‐Liss, Inc.