bluuebunny/crossref_metadata_2025 huggingface dataset:
Taurine supplementation prevents ethanol-induced decrease in serum adiponectin and reduces hepatic steatosis in rats #
Authors: Chen Xiaocong , Sebastian Becky M. , Tang Hui , McMullen Megan M. , Axhemi Armend , Jacobsen Donald W. , Nagy Laura E.
Published: December 2008

Chronic ethanol feeding decreases expression of adiponectin by adipocytes and circulating adiponectin. Adiponectin treatment during chronic ethanol feeding prevents liver injury in mice. Chronic ethanol feeding also increases oxidative and endoplasmic reticulum (ER) stress in adipose tissue. Here we tested the hypothesis that supplemental taurine, an amino acid that functions as a chemical chaperone/osmolyte and enhances cellular antioxidant activity, would prevent ethanol-induced decreases in adiponectin expression and attenuate liver injury. Serum adiponectin concentrations decreased as early as 4 to 7 days after feeding rats a 36% ethanol diet. This rapid decrease was associated with increased oxidative, but not ER, stress in subcutaneous adipose tissue. Taurine prevented ethanol-induced oxidative stress and increased inflammatory cytokine expression in adipose tissue. Ethanol feeding also rapidly decreased expression of transcription factors regulating adiponectin expression (CCAAT/enhancer binding protein α; peroxisome proliferator-activated receptor α/γ) in subcutaneous adipose tissue. Taurine prevented the ethanol-induced decrease in CCAAT/enhancer binding protein α and peroxisome proliferator-activated receptor α, normalizing adiponectin messenger (m)RNA and serum adiponectin concentrations. In the liver, taurine prevented ethanol-induced oxidative stress and attenuated tumor necrosis factor α expression and steatosis, at least in part, by increasing expression of genes involved in fatty acid oxidation. Conclusion: In subcutaneous adipose tissue, taurine decreased ethanol-induced oxidative stress and cytokine expression, as well as normalized expression of adiponectin mRNA. Taurine prevented ethanol-induced decreases in serum adiponectin; normalized adiponectin was associated with a reduction in hepatic oxidative stress, tumor necrosis factor α expression, and steatosis. Taken together, these data demonstrate that taurine has important protective effects against ethanol-induced tissue injury in both adipose and liver tissue. (Hepatology 2009.)
Loss of protein kinase Cβ function protects mice against diet-induced obesity and development of hepatic steatosis and insulin resistance #
Authors: Huang Wei , Bansode Rishipal , Mehta Madhu , Mehta Kamal D.
Published: December 2008

Obesity is an energy balance disorder in which intake is greater than expenditure, with most excess calories stored as triglyceride (TG). We previously reported that mice lacking the β-isoform of protein kinase C (PKCβ), a diacylglycerol- and phospholipid-dependent kinase, exhibit marked reduction in the whole body TG content, including white adipose tissue (WAT) mass. To investigate the role of this signaling kinase in metabolic adaptations to severe dietary stress, we studied the impact of a high-fat diet (HFD) on PKCβ expression and the effect of PKCβ deficiency on profound weight gain. We report herein that HFD selectively increased PKCβ expression in obesity-prone C57BL/6J mice, specifically in WAT; the expression levels were little or unchanged in the liver, muscle, kidney, and heart. Basal PKCβ expression was also found to be elevated in WAT of obese ob/ob mice. Remarkably, mice lacking PKCβ were resistant to HFD-induced obesity, showing significantly reduced WAT and slightly higher core body temperatures. Unlike lean lipodystrophic mouse models, these mice did not have fatty livers, nor did they exhibit insulin resistance. Moreover, PKCβ−/− mice exhibited changes in lipid metabolism gene expression, and such alterations were accompanied by significant changes in serum adipokines. These observations suggest that PKCβdeficiency induced a unique metabolic state congruous with obesity resistance, thus raising the possibility that dysregulation of PKCβ expression could contribute to dietary fat–induced obesity and related disorders. (Hepatology 2009.)
Supra‐normal age‐linked retrograde amnesia: Lessons from an older amnesic (H.M.)
Authors: MacKay Donald G. , Hadley Christopher
Published: December 2008

MacKay and James (2001) demonstrated greater‐than‐normal retrograde amnesia (RA) for lexical‐semantic information in amnesic H.M., a deficit that worsened with aging or represented supranormal age‐linked RA (SARA). The present experiments extend these earlier observations to new types of information. Experiment 1 participants (H.M. and carefully matched memory‐normal controls) named pictures on the Boston Naming Test and H.M. correctly named reliably fewer pictures with low frequency names, he produced unusual naming errors, and he benefited reliably less than the controls from phonological cues to the target word. Experiment 2 participants recalled irregularly‐spelled aspects of familiar words in a two‐choice recognition memory task and H.M. chose the correct spelling reliably less often than the controls. Experiment 3 participants read low frequency words aloud at age 73 and H.M. produced reliably more reading errors than the controls. Results of all three experiments indicate supranormal RA (SRA) for information once familiar to H.M. and comparisons with earlier studies using similar or identical stimuli indicated that H.M.'s SRA has worsened with aging from 1980 to 1999. In short, H.M. exhibits SARA for phonological and orthographic information, consistent with the MacKay and James results and with interactions between aging and amnesia predicted under binding theory. © 2008 Wiley‐Liss, Inc.
Stimulation of NMDA and AMPA glutamate receptors elicits distinct concentration dynamics of nitric oxide in rat hippocampal slices
Authors: Frade J.G. , Barbosa R.M. , Laranjinha J.
Published: December 2008

Nitric oxide (•NO) is an intercellular messenger implicated in memory formation and neurodegeneration in the hippocampus. Owing to its physical and chemical properties, the concentration dynamics of•NO is a critical issue in determining its bioactivity as a signaling molecule. Its production is closely related to glutamateN‐methyl‐D‐aspartate (NMDA) receptors, following a rise in intracellular calcium levels. However, that dependent on α‐amino‐3‐hydroxy‐5‐methylisoxazole‐4‐propionate (AMPA) receptors remains elusive and controversial, despite reports describing a role for these receptors in other brain regions, largely because of lack of quantitative and dynamic measurements of•NO. Using a•NO‐selective microsensor inserted in the diffusional spread of•NO in the CA1 region of rat hippocampal slices, we measured its real‐time endogenous production, following activation of ionotropic glutamate receptors and under tissue physiological oxygen tension. Both NMDA and AMPA stimulation resulted in a concentration‐dependent•NO production but encompassing distinct kinetics for lag phases and slower rates of•NO production were observed for AMPA stimulation. Robustness of the results was achieved instrumentally and pharmacologically, by means of nitric oxide synthase (NOS) inhibitors and antagonists of NMDA (D‐(−)‐2‐amino‐5‐phosphonopentanoic acid, AP5) and AMPA (2,3‐dioxo‐6‐nitro‐1,2,3,4‐tetrahydrobenzo[f]quinoxaline‐7‐sulfonamide, NBQX) receptors. When using glutamate as a stimulus,•NO production was of lower magnitude in the presence of AP5 plus NBQX than with AP5 alone, suggesting that even when NMDA receptors are inhibited Ca2+rises to levels to induce a peak of•NO from the background. Whereas extracellular Ca2+was required for the•NO signals, Philanthotoxin‐4,3,3 (PhTX‐4,3,3) a toxin used to target Ca2+‐permeable AMPA receptors, attenuated•NO production. These observations are interpreted on basis of a distinct coupling between the glutamate receptors and neuronal NOS. A role for Ca2+‐permeable AMPA receptors in the Ca2+activation of neuronal NOS is suggested. © 2008 Wiley‐Liss, Inc.
The effects of IL‐1 receptor antagonist on beta amyloid mediated depression of LTP in the rat CA1 in vivo
Authors: Schmid Adrien W. , Lynch Marina A. , Herron Caroline E.
Published: December 2008

Beta‐amyloid (Aβ) is a neuro‐peptide implicated in the pathogenesis of Alzheimer's disease (AD). Aβ‐peptide is known to disrupt cellular processes, including synaptic plasticity. To date, the precise mechanisms leading to the Aβ‐mediated impairment of normal neurophysiological function still remains elusive. A rise in the pro‐inflammatory cytokine interleukin‐1‐β (IL‐1β) has been previously reported, following Aβ peptide insult. IL‐1β in turn, activates a cascade of pro‐apoptotic markers, gradually leading to cell death. In this work, we have investigated the possible protective effects of interleukin‐1 receptor antagonist (IL‐1ra) on the effects of Aβ‐peptide on long‐term potentiation (LTP) in the CA1 region of the rat hippocampus in vivo. We observed a significant depression of LTP in the group of animals that received intracerebroventricular (icv) injection of Aβ‐peptide (1–40) compared with control animals injected with vehicle. Administration of IL‐1ra alone (icv) also resulted in a depression of LTP; however, there was no change in the baseline synaptic response. Combined injection of Aβ(1–40) + IL‐1ra caused an attenuation of the effects observed with Aβ(1–40) alone for a period of up to 15 min following LTP induction; rescuing post‐tetanicpotentiation (PTP). Gradually however, EPSP‐values declined to produce a level of LTP similar to that observed following treatment with Aβ(1–40) alone. These results suggest that the acute Aβ‐mediated impairment of PTP and LTP may be partial as a result of activation of an inflammatory response and the release of IL‐1β. The attenuation of plasticity by IL‐1ra alone supports the theory that low levels of IL‐1β are required for normal synaptic plasticity. The limited rescue of the Aβ‐mediated effects on LTP, in the presence of IL‐1ra, may represent the short half life found with this receptor antagonist in vivo. © 2008 Wiley‐Liss, Inc.
Two‐dimensional physically based finite element runoff model for small agricultural watersheds: II. Model testing and field application
Authors: Bhardwaj Anil , Kaushal M. P.
Published: December 2008

Mathematical models are useful analysis tools to understand problems in watersheds associated with runoff, and to find solutions through land use changes and best management practices. However, before a model is applied in the field, it must be tested and checked to ensure that the model represents the real world adequately. In this paper, a two‐dimensional physically based finite element runoff model ROMO2D has been verified and validated by comparing the model output with analytic solution under simplified conditions, published data, and field measurements. Calibration of the model was done manually through a multi‐objective calibration procedure, using observed field data. Before going for field validation/application of ROMO2D, analysis was carried out to determine the optimum number of finite elements into which the watershed should be discretized and the size of the time step. A sensitivity analysis of the model was performed using the observed values of watershed parameters. The model was applied to a 1·45 ha agricultural watershed located in the Shiwalik foothills (India) to simulate runoff. The results demonstrated the potential of the model to simulate runoff from small agricultural watersheds for individual storm events with reasonable accuracy. Copyright © 2008 John Wiley & Sons, Ltd.
Implications of global climate change for snowmelt hydrology in the twenty‐first century
Authors: Adam Jennifer C. , Hamlet Alan F. , Lettenmaier Dennis P.
Published: December 2008

For most of the global land area poleward of about 40° latitude, snow plays an important role in the water cycle. The (seasonal) timing of runoff in these areas is especially sensitive to projected losses of snowpack associated with warming trends, whereas projected (annual) runoff volume changes are primarily associated with precipitation changes, and to a lesser extent, with changes in evapotranspiration (ET). Regional studies in the USA (and especially the western USA) suggest that hydrologic adjustments to a warming climate have been ongoing since the mid‐twentieth century. We extend the insights extracted from the western USA to the global scale using a physically based hydrologic model to assess the effects of systematic changes in precipitation and temperature on snow‐affected portions of the global land area as projected by a suite of global climate models. While annual (and in some cases seasonal) changes in precipitation are a key driver of projected changes in annual runoff, we find, as in the western USA, that projected warming produces strong decreases in winter snow accumulation and spring snowmelt over much of the affected area regardless of precipitation change. Decreased snowpack produces decreases in warm‐season runoff in many mid‐ to high‐latitude areas where precipitation changes are either moderately positive or negative in the future projections. Exceptions, however, occur in some high‐latitude areas, particular in Eurasia, where changes in projected precipitation are large enough to result in increased, rather than decreased, snow accumulation. Overall, projected changes in snowpack and the timing of snowmelt‐derived runoff are largest near the boundaries of the areas that currently experience substantial snowfall, and at least qualitatively, they mirror the character of observed changes in the western USA. Copyright © 2008 John Wiley & Sons, Ltd.
Simulated soil water storage effects on streamflow generation in a mountainous snowmelt environment, Idaho, USA
Authors: Seyfried M. S. , Grant L. E. , Marks D. , Winstral A. , McNamara J.
Published: December 2008

Although soil processes affect the timing and amount of streamflow generated from snowmelt, they are often overlooked in estimations of snowmelt‐generated streamflow in the western USA. The use of a soil water balance modelling approach to incorporate the effects of soil processes, in particular soil water storage, on the timing and amount of snowmelt generated streamflow, was investigated. The study was conducted in the Reynolds Mountain East (RME) watershed, a 38 ha, snowmelt‐dominated watershed in southwest Idaho. Snowmelt or rainfall inputs to the soil were determined using a well established snow accumulation and melt model (Isnobal). The soil water balance model was first evaluated at a point scale, using periodic soil water content measurements made over two years at 14 sites. In general, the simulated soil water profiles were in agreement with measurements (P < 0·05) as further indicated by high R2 values (mostly > 0·85), y‐intercept values near 0, slopes near 1 and low average differences between measured and modelled values. In addition, observed soil water dynamics were generally consistent with critical model assumptions. Spatially distributed simulations over the watershed for the same two years indicate that streamflow initiation and cessation are closely linked to the overall watershed soil water storage capacity, which acts as a threshold. When soil water storage was below the threshold, streamflow was insensitive to snowmelt inputs, but once the threshold was crossed, the streamflow response was very rapid. At these times there was a relatively high degree of spatial continuity of satiated soils within the watershed. Incorporation of soil water storage effects may improve estimation of the timing and amount of streamflow generated from mountainous watersheds dominated by snowmelt. Copyright © 2008 John Wiley & Sons, Ltd.
Institutional aspects of integrating irrigation into urban wastewater management: the case of Hanoi, Vietnam
Authors: Evers Jaap G. , Huibers Frans P. , van Vliet Bas J.M.
Published: December 2008

Wastewater flows of metropolitan cities and their downstream use for irrigation are often associated with technical systems. However, an engineering approach on its own will leave questions unanswered at the socio‐technical and institutional level. Research was carried out in Hanoi, Vietnam, on the use of polluted irrigation water in periurban agriculture. Apart from outlining the physical features of the urban wastewater chain, a supply chain approach has been applied. Stakeholders along the management chain of the conventional urban wastewater system resemble “spot markets” (independent actors who act in self‐interest) as described in supply chain management literature. In Hanoi, the conventional approach towards wastewater management consists of a strict separation of urban wastewater management from periurban agricultural use and a neglect of farmers as stakeholders in the chain. It is suggested that the use of wastewater in agriculture should be incorporated into urban water management systems and that farmers should be included as acting stakeholders in the management of the wastewater chain. This paper concludes with suggestions for urban water management that are necessary to combine urban wastewater management with periurban agriculture. Copyright © 2008 John Wiley & Sons, Ltd.
Comparative protective effect of N‐acetyl cysteine and tetramethylpyrazine in rats with gentamicin nephrotoxicity
Authors: Ali B. H. , Al–Salam S. , Al‐Husseini I. , Nemmar A.
Published: December 2008

Gentamicin (GM) is used against serious and life‐threatening infections, but its use is limited by the occurrence of nephrotoxicity, which involves the generation of free radicals. In this work we tested the effect of a compound with antioxidant properties, tertamethylpyrazine (TMP), a major constituent of the Chinese medicinal plant Lingusticum wallichi, on GM‐induced nephrotoxicity, and compared it with an established anti‐oxidant compound N‐acetyl cysteine (NAC). Six groups of rats were studied: (1) control, treated orally (p.o.) and intraperitoneally (i.p.) with saline; (2) treated i.p. with GM (80 mg kg–1 per day for 6 days); (3) TMP, given p.o. (100 mg kg–1 per day for 10 days) + GM (same dose as above during the last 6 days); (4) NAC, given i.p. (500 mg kg–1 per day for 10 days) + GM as above; (5) TMP (100 mg kg–1 per day for 10 days) + saline; (6) NAC (500 mg kg–1 per day for 10 days) + saline. GM nephrotoxicity was characterized by reduced creatinine clearance, increased creatinine and urea concentrations in plasma, increased urinary excretion of N‐acetyl‐β‐d‐glucosaminidase (NAG) and total protein. These functional and structural alterations were prevented or ameliorated by NAC treatment, while TMP had only a slight mitigating effect that was less marked than that produced by NAC. The concentration of GM in the renal cortex of the rats given GM + NAC (but not TMP) was lower than that found in rats treated with GM alone by about 25%. The mechanism by which NAC and, to a lesser extent TMP, protected against GM‐induced nephrotoxicity may be related, at least in part, to the decrease in oxidative stress in renal cortex. Copyright © 2008 John Wiley & Sons, Ltd.
5‐Fluorouracil and its active metabolite FdUMP cause DNA damage in human SW620 colon adenocarcinoma cell line
Authors: Matuo Renata , Sousa Fabrício Garmus , Escargueil Alexandre E. , Grivicich Ivana , Garcia‐Santos Daniel , Chies José Artur Bogo , Saffi Jenifer , Larsen Annette K. , Henriques João Antonio Pêgas
Published: December 2008

5‐Fluorouracil (5‐FU) is an antineoplasic drug widely used to treat cancer. Its cytotoxic effect has been principally ascribed to the misincorporation of fluoronucleotides into DNA and RNA during their synthesis, and the inhibition of thymidylate synthase (TS) by FdUMP (one of the 5‐FU active metabolites), which leads to nucleotide pool imbalance. In the present study, we compared the ability of 5‐FU and FdUMP to induce apoptosis and to influence the cell cycle progression in human colon SW620 adenocarcinoma cells in regards to their genotoxic and clastogenic activities. Our study demonstrates that 5‐FU induces SSB, DSB and apoptosis earlier than FdUMP. Interestingly, while both drugs are able to induce apoptosis, their effect on the cell cycle progression differed. Indeed, 5‐FU induces an arrest in G1/S while FdUMP causes an arrest in G2/M. Independently of the temporal difference in strand breaks and apoptosis induction, as well as the differential cell cycle modulation, both drugs presented similar clastogenic effects. The different pattern of cell cycle arrest suggests that the two drugs induce different types of primary DNA lesions that could lead to the activation of different checkpoints and recruit different DNA repair pathways. Copyright © 2008 John Wiley & Sons, Ltd.
Isocyanates induces DNA damage, apoptosis, oxidative stress, and inflammation in cultured human lymphocytes
Authors: Mishra Pradyumna Kumar , Panwar Hariom , Bhargava Arpit , Gorantla Venkata Raghuram , Jain Subodh Kumar , Banerjee Smita , Maudar Kewal Krishan
Published: December 2008

Isocyanates, a group of low molecular weight aromatic and aliphatic compounds containing the isocyanate group (−NCO), are important raw materials with diverse industrial applications; however, pathophysiological implications resulting from occupational and accidental exposures of these compounds are hitherto unknown. Although preliminary evidence available in the literature suggests that isocyanates and their derivatives may have deleterious health effects including immunotoxicity, but molecular mechanisms underlying such an effect have never been addressed. The present study was carried out to assess the immunotoxic response of methyl isocyanate (MIC) on cultured human lymphocytes isolated from healthy human volunteers. Studies were conducted to evaluate both dose‐dependent and time‐course response (n = 3), using N‐succinimidyl N‐methylcarbamate, a surrogate chemical substitute to MIC. Evaluation of DNA damage by ataxia telangiectasia mutated (ATM) and γ H2AX protein phosphorylation states; measure of apoptotic index through annexin‐V/PI assay, apoptotic DNA ladder assay, and mitochondrial depolarization; induction of oxidative stress by CM‐H2DCFDA and formation of 8‐hydroxy‐2′ deoxy guanosine; levels of antioxidant defense system enzyme glutathione reductase; and multiplex cytometric bead array analysis to quantify the secreted levels of inflammatory cytokines, interleukin‐8, interleukin‐1β, interleukin‐6, interleukin‐10, tumor necrosis factor, and interleukin‐12p70 parameters were carried out. The results of the study showed a dose‐ and time‐dependent response, providing evidence to hitherto unknown molecular mechanisms of immunotoxic consequences of isocyanate exposure at a genomic level. We anticipate these data along with other studies reported in the literature would help to design better approaches in risk assessment of occupational and accidental exposure to isocyanates. © 2008 Wiley Periodicals, Inc. J Biochem Mol Toxicol 22:429–440, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20260
Segment‐specific proximal tubule injury in tripterygium glycosides intoxicated rats
Authors: Dan Hong , Peng Ren‐Xiu , Ao Ying , Liu Ying‐Hui
Published: December 2008

Tripterygium glycosides (TG), extracted from the Chinese herbTripterygium wilfordiiHook. f, is a widely used anti‐inflammatory and immunosuppressive agent with definite nephrotoxicity. However, its toxic mechanism remained undiscovered. The aim of this study was to characterize the potential toxicity of TG on segments of proximal tubule in rats. Six hundred and 1200 mg/kg of TG was administered by daily intragastric instillation for 16 days. A significant reduction ofp‐aminohippurate accumulation by renal cortical slices indicated that TG damaged organic anion transporter (OAT) system that localized at the proximal tubule, especially S2segment. A dramatic loss of kidney glutamine synthetase (GS) activity induced by TG reflected S3segment damage. Because mRNA expression of OAT1, OAT3, and GS was decreased substantially, we ascribe the fall ofp‐aminohippurate accumulation and GS activity to alterations at the transcriptional level. A dose‐related diminution of kidney glutathione S‐transferase activity was noted simultaneously, suggesting oxidative stress involvement. Histopathological lesions were observed in the TG intoxicated rat kidney even though there were no obvious changes of serum urea and creatinine at this dose level. In summary, we provided evidences supporting that TG caused segment‐specific dysfunction in the kidney proximal tubule. © 2008 Wiley Periodicals, Inc. J Biochem Mol Toxicol 22:422–428, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20261
PPARγ2 nuclear receptor controls multiple regulatory pathways of osteoblast differentiation from marrow mesenchymal stem cells
Authors: Shockley Keith R. , Lazarenko Oxana P. , Czernik Piotr J. , Rosen Clifford J. , Churchill Gary A. , Lecka‐Czernik Beata
Published: December 2008

Rosiglitazone (Rosi), a member of the thiazolidinedione class of drugs used to treat type 2 diabetes, activates the adipocyte‐specific transcription factor peroxisome proliferator‐activated receptor gamma (PPARγ). This activation causes bone loss in animals and humans, at least in part due to suppression of osteoblast differentiation from marrow mesenchymal stem cells (MSC). In order to identify mechanisms by which PPARγ2 suppresses osteoblastogenesis and promotes adipogenesis in MSC, we have analyzed the PPARγ2 transcriptome in response to Rosi. A total of 4,252 transcriptional changes resulted when Rosi (1 µM) was applied to the U‐33 marrow stromal cell line stably transfected with PPARγ2 (U‐33/γ2) as compared to non‐induced U‐33/γ2 cells. Differences between U‐33/γ2 and U‐33 cells stably transfected with empty vector (U‐33/c) comprised 7,928 transcriptional changes, independent of Rosi. Cell type‐, time‐ and treatment‐specific gene clustering uncovered distinct patterns of PPARγ2 transcriptional control of MSC lineage commitment. The earliest changes accompanying Rosi activation of PPARγ2 included effects on Wnt, TGFβ/BMP and G‐protein signaling activities, as well as sustained induction of adipocyte‐specific gene expression and lipid metabolism. While suppression of osteoblast phenotype is initiated by a diminished expression of osteoblast‐specific signaling pathways, induction of the adipocyte phenotype is initiated by adipocyte‐specific transcriptional regulators. This indicates that distinct mechanisms govern the repression of osteogenesis and the stimulation of adipogenesis. The co‐expression patterns found here indicate that PPARγ2 has a dominant role in controlling osteoblast differentiation and suggests numerous gene‐gene interactions that could lead to the identification of a “master” regulatory scheme directing this process. J. Cell. Biochem. 106: 232–246, 2009. © 2008 Wiley‐Liss, Inc.
The interaction of KCTD1 with transcription factor AP‐2α inhibits its transactivation
Authors: Ding Xiaofeng , Luo Chang , Zhou Jianlin , Zhong Yingli , Hu Xiang , Zhou Fangliang , Ren Kaiqun , Gan Lu , He Ailan , Zhu Jiaolian , Gao Xiang , Zhang Jian
Published: December 2008

AP‐2 is a transcription factor implicated in mammalian development, cell proliferation, apoptosis, and carcinogenesis. To identify potential AP‐2α‐interacting partners, a yeast two‐hybrid screen was performed in human brain cDNA library. One of the identified clones encodes potassium channel tetramerization domain‐containing 1 (KCTD1). We demonstrated the novel KCTD1–AP‐2α interaction in vitro by GST pull‐down assays and in vivo by co‐immunoprecipitation assays and mapped the interaction domains to the N‐termini of both proteins. In addition, we observed that the two proteins were completely co‐localized in the nuclei of mammalian cells. Transient transfection assays using four promoters containing AP‐2‐binding sites confirmed that KCTD1 significantly repressed AP‐2α‐mediated transactivation through the BTB domain, whereas KCTD1 siRNA strongly relieved KCTD1‐mediated repression of AP‐2α transcriptional activity, and other BTB domain proteins such as PDIP1, KCTD10, and TNFAIP1 did not markedly inhibit the transcriptional activity of AP‐2α, suggesting that KCTD1 specifically acts as a negative regulator of AP‐2α. Finally, we found that KCTD1 interacted with three major members of the AP‐2 family and inhibited their transcriptional activities. Taken together, our results indicate the novel function of KCTD1 as the transcriptional repressor for AP‐2 family, especially for AP‐2α. J. Cell. Biochem. 106: 285–295, 2009. © 2008 Wiley‐Liss, Inc.
Transcriptional regulation of human eosinophil RNase2 by the liver‐enriched hepatocyte nuclear factor 4
Authors: Wang Hsiu‐Yu , Ho Po‐Chun , Lan Chung‐Yu , Chang Margaret Dah‐Tsyr
Published: December 2008

Human eosinophil‐derived neurotoxin (EDN, RNase2) and eosinophil cationic protein (ECP, RNase3) sequences possess as high as 92% identity in their promoter regions. The major difference within this region is a 34‐nucleotide (34‐nt) segment appeared only in the edn promoter. In addition, six discrete segments existed in the regulatory regions of both edn and ecp. Our previous study indicated that the 34‐nt segment is responsive for higher transcription activity of edn in comparison with ecp, via binding to transcription activator Sp1. In this study, the roles of the six discrete segments in transcription regulation were investigated and the −350/−329 region (ednR2) was shown to be involved in the regulation of edn expression. When the ednR2 segment of edn was replaced with that of ecp, a significant decrease in edn promoter activity was detected. Supershift, chromatin immunoprecipitation, and DNA affinity precipitation assays further showed that a transcription factor HNF4 bound to the ednR2 region of edn promoter in vitro. Interestingly, HNF4 overexpression resulted in the reduction of edn promoter activity in HepG2 cells, due to involvement of both ednR2 and the 34‐nt regions, and direct interaction between HNF4 and Sp1, which abolishes Sp1 binging to the 34‐nt segment. Moreover, when the Sp1 was depleted in the cell, overexpressed HNF4 enhanced edn promoter activity. Our results provide novel mechanisms for HNF4 function as an activator to regulate edn promoter activity, which account for differential transcription regulation of human eosinophil RNases. J. Cell. Biochem. 106: 317–326, 2009. © 2008 Wiley‐Liss, Inc.
Defects in intracellular trafficking and endocytic/vacuolar acidification determine the efficiency of endocytotic DNA uptake in yeast
Authors: Riechers Sean‐Patrick , Stahl Ulf , Lang Christine
Published: December 2008

The yeast Saccharomyces cerevisiae is a standard model system to study endocytosis. Here we describe the examination of a representative subset of deletion mutants to identify and locate steps in endocytic transport, endosomal/lysosomal acidification and in intracellular transport of hydrolases in non‐viral transfection processes. When transport in late endocytosis is inhibited, transfection efficiency is significantly enhanced. Similarly, transfection efficiency is enhanced when the pH‐value of the endosomal/vacuolar system is modified. Transfection efficiency is furthermore elevated when the Na+/K+ transport in the endosomal system is disturbed. Finally, we observe enhanced transfection efficiency in mutants disturbed in the CVT/autophagy pathway and in hydrolase transport to the vacuole. In summary, non‐viral transfection efficiency can be significantly increased by either (i) inhibiting the transport of endocytosed material before it enters the vacuole, or (ii) inducing a non‐natural pH‐value of the endosomal/vacuolar system, or (iii) slowing down degradative processes by inhibiting vacuolar hydrolases or the transport between Golgi and late endosome/vacuole. J. Cell. Biochem. 106: 327–336, 2009. © 2008 Wiley‐Liss, Inc.
Effects of age and gender on WNT gene expression in human bone marrow stromal cells
Authors: Shen Longxiang , Zhou Shuanhu , Glowacki Julie
Published: December 2008

WNT signaling pathways play important roles in the behavior of human bone marrow stromal cells. Although WNT expression has been examined in human bone marrow stromal cells (hMSCs) with limited numbers of subjects or from commercial sources, there are conflicting results on WNT gene expression in hMSCs. Furthermore, the effects of age and gender on WNT expression in hMSCs are largely unknown. In this study, we evaluated RNA expression of all the WNT genes in hMSCs from 19 subjects, 12 women and 7 men, aged from 36 to 85 years. Analysis of WNT gene expression in young and old groups indicated that WNT7B and 14 were expressed significantly higher in the young group. WNT2 and WNT13 showed a trend of higher expression in young group. WNT7B, 13, and 14 were inversely correlated with age. Further analysis for gender‐specific difference indicated that WNT16 was expressed significantly higher in men than in women. WNT11 showed a trend of higher expression in hMSCs from women. For the hMSCs from women, WNT13 was inversely correlated with age and WNT4 was positively correlated with age. For the hMSCs from men, WNT7B and WNT14 were inversely correlated with age. These data indicated that most of the age‐related WNT genes belong to the canonical WNT signaling pathway. Further, there are gender‐specific differences in the expression of WNT4, 7B, 13, 14, and 16 in hMSCs. Age and gender account for many of the sample‐to‐sample variations in WNT gene expression in human marrow stromal cells. J. Cell. Biochem. 106: 337–343, 2009. © 2008 Wiley‐Liss, Inc.
Insulin induces the low density lipoprotein receptor‐related protein 1 (LRP1) degradation by the proteasomal system in J774 macrophage‐derived cells
Authors: Ceschin Danilo G. , Sánchez María C. , Chiabrando Gustavo A.
Published: December 2008

Low‐density lipoprotein receptor‐related protein 1 (LRP1) is an endocytic receptor, which binds and internalizes diverse ligands such as activated α2‐macroglobulin (α2M*). LRP1 promotes intracellular signaling, which downstream mediates cellular proliferation and migration of different types of cells, including macrophages. Unlike the LDL receptor, LRP1 expression is not sensitive to cellular cholesterol levels but appears to be responsive to insulin. It has been previously demonstrated that insulin increases the cell surface presentation of LRP1 in adipocytes and hepatocytes, which is mediated by the intracellular PI3K/Akt signaling activation. The LRP1 protein distribution is similar to other insulin‐regulated cell surface proteins, including transferring receptor (Tfr). However, in macrophages, the insulin effect on the LRP1 distribution and expression is not well characterized. Considering that macrophages play a central role in the pathogenesis of atherosclerosis, herein we evaluate the effect of insulin on the cellular expression of LRP1 in J774 macrophages‐derived cells using Western blot and immunofluorescence microscopy. Our data demonstrate that insulin induces a significant decrease in the LRP1 protein content, without changing the specific mRNA level of this receptor. Moreover, insulin specifically affected the protein expression of LRP1 but not Tfr. The insulin‐induced protein degradation of LRP1 in J774 cells was mediated by the activation of the PI3K/Akt pathway and proteasomal system by an enhanced ubiquitin–receptor conjugation. The decreased content of LRP1 induced by insulin affected the cellular internalization of α2M*. Thus, we propose that the protein degradation of LRP‐1 induced by insulin in macrophages could have important effects on the pathogenesis of atherosclerosis. J. Cell. Biochem. 106: 372–380, 2009. © 2008 Wiley‐Liss, Inc.
Autophosphorylation of carboxy‐terminal residues inhibits the activity of protein kinase CK1α
Authors: Budini Mauricio , Jacob Germaine , Jedlicki Ana , Pérez Carolina , Allende Catherine C. , Allende Jorge E.
Published: December 2008

CK1 constitutes a protein kinase subfamily that is involved in many important physiological processes. However, there is limited knowledge about mechanisms that regulate their activity. Isoforms CK1δ and CK1ε were previously shown to autophosphorylate carboxy‐terminal sites, a process which effectively inhibits their catalytic activity. Mass spectrometry of CK1α and splice variant CK1αL has identified the autophosphorylation of the last four carboxyl‐end serines and threonines and also for CK1αS, the same four residues plus threonine‐327 and serine‐332 of the S insert. Autophosphorylation occurs while the recombinant proteins are expressed in Escherichia coli. Mutation of four carboxy‐terminal phosphorylation sites of CK1α to alanine demonstrates that these residues are the principal but not unique sites of autophosphorylation. Treatment of autophosphorylated CK1α and CK1αS with λ phosphatase causes an activation of 80–100% and 300%, respectively. Similar treatment fails to stimulate the CK1α mutants lacking autophosphorylation sites. Incubation of dephosphorylated enzymes with ATP to allow renewed autophosphorylation causes significant inhibition of CK1α and CK1αS. The substrate for these studies was a synthetic canonical peptide for CK1 (RRKDLHDDEEDEAMS*ITA). The stimulation of activity seen upon dephosphorylation of CK1α and CK1αS was also observed using the known CK1 protein substrates DARPP‐32, β‐catenin, and CK2β, which have different CK1 recognition sequences. Autophosphorylation effects on CK1α activity are not due to changes in Kmapp for ATP or for peptide substrate but rather to the catalytic efficiency per pmol of enzyme. This work demonstrates that CK1α and its splice variants can be regulated by their autophosphorylation status. J. Cell. Biochem. 106: 399–408, 2009. © 2008 Wiley‐Liss, Inc.
Protein kinase‐A affects sorting and conformation of the sodium‐dependent glucose co‐transporter SGLT1
Authors: Subramanian Supriya , Glitz Petra , Kipp Helmut , Kinne Rolf K.H. , Castaneda Francisco
Published: December 2008

In Chinese hamster ovary cells expressing rabbit sodium‐dependent glucose transporter (rbSGLT1) protein kinase A (PKA) activators (forskolin and 8‐Br‐cAMP) stimulated α‐methyl D‐glucopyranoside uptake. Kinetic analysis revealed an increase in both Vmax and affinity of the transport. Immunohistochemistry and biotinylation experiments showed that this stimulation was accompanied by an increased amount of SGLT1 localized into the plasma membrane, which explains the higher Vmax of the transport. Cytochalasin D only partly attenuated the effect of forskolin as did deletion of the PKA phosphorylation site of SGLT1 in transient transfection studies. Experiments using an anti‐phosphopeptide antibody revealed that forskolin also increased the extent of phosphorylation of SGLT1 in the membrane fraction. These results suggested that regulation of SGLT1 mediated glucose transport involves an additional direct effect on SGLT1 by phosphorylation. To evaluate this assumption further, phosphorylation studies of recombinant human SGLT1 (hSGLT1) in vitro were performed. In the presence of the catalytic subunit PKA and [32P] ATP 1.05 mol of phosphate were incorporated/mol of hSGLT1. Additionally, phosphorylated hSGLT1 demonstrated a reduction in tryptophan fluorescence intensity and a higher quenching by the hydrophilic Trp quencher acrylamide, particularly in the presence of D‐glucose. These results indicate that PKA‐mediated phosphorylation of SGLT1 changes the conformation of the empty carrier and the glucose carrier complex, probably causing the increase in transport affinity. Thus, PKA‐mediated phosphorylation of the transporter represents a further mechanism in the regulation of SGLT1‐mediated glucose transport in epithelial cells, in addition to a change in surface membrane expression. J. Cell. Biochem. 106: 444–452, 2009. © 2008 Wiley‐Liss, Inc.
T‐box 3 negatively regulates osteoblast differentiation by inhibiting expression of osterix and runx2
Authors: Govoni K.E. , Linares G.R. , Chen S‐T. , Pourteymoor S. , Mohan S.
Published: December 2008

T‐box (Tbx)3, a known transcriptional repressor, is a member of a family of transcription factors, which contain a highly homologous DNA binding domain known as the Tbx domain. Based on the knowledge that mutation of the Tbx3 gene results in limb malformation, Tbx3 regulates osteoblast proliferation and its expression increases during osteoblast differentiation, we predicted that Tbx3 is an important regulator of osteoblast cell functions. In this study, we evaluated the consequence of transgenic overexpression of Tbx3 on osteoblast differentiation. Retroviral overexpression increased Tbx3 expression >100‐fold at the mRNA and protein level. Overexpression of Tbx3 blocked mineralized nodule formation (28 ± 8 vs. 7 ± 1%) in MC3T3‐E1 cells. In support of these data, alkaline phosphatase (ALP) activity was reduced 33–70% (P < 0.05) in both MC3T3‐E1 cells and primary calvaria osteoblasts overexpressing Tbx3. In contrast, Tbx3 overexpression did not alter ALP activity in bone marrow stromal cells. Tbx3 overexpression blocked the increase in expression of key osteoblast marker genes, ALP, bone sialoprotein, and osteocalcin that occurs during normal osteoblast differentiation, but had little or no effect on expression of proliferation genes p53 and Myc. In addition, Tbx3 overexpression abolished increased osterix and runx2 expression observed during normal osteoblast differentiation, but the change in Msx1 and Msx2 expression over time was similar between control and Tbx3 overexpressing cells. Interestingly, osterix and runx2, but not Msx1 and Msx2, contain Tbx binding site in the regulatory region. Based on these data and our previous findings, we conclude that Tbx3 promotes proliferation and suppresses differentiation of osteoblasts and may be involved in regulating expression of key transcription factors involved in osteoblast differentiation. J. Cell. Biochem. 106: 482–490, 2009. © 2008 Wiley‐Liss, Inc.
Prediction of human cytochrome P450 2B6‐substrate interactions using hierarchical support vector regression approach
Authors: Leong Max K. , Chen Yen‐Ming , Chen Tzu‐Hsien
Published: December 2008

The human cytochrome P450 2B6 can metabolize a number of clinical drugs. Inhibition of CYP2B6 by coadministered multiple drugs may lead to drug–drug interactions and undesired drug toxicity. The aim of this investigation is to develop anin silicomodel to predict the interactions between P450 2B6 and novel inhibitors using a novel hierarchical support vector regression (HSVR) approach, which simultaneously takes into account the coverage of applicability domain (AD) and the level of predictivity. Thirty‐seven molecules were deliberately selected and rigorously scrutinized from the literature data, of which 26 and 11 molecules were treated as the training set and the test set to generate the models and to validate the generated models, respectively. The generated HSVR model gave rise to anr2value of 0.97 for observed versus predicted pKmvalues for the training set, aq2value of 0.93 by the 10‐fold cross‐validation, and anr2value of 0.82 for the test set. Additionally, the predicted results show that the HSVR model outperformed the individual local models, the global model, and the consensus model. Thus, this HSVR model provides an accurate tool for the prediction of human cytochrome P450 2B6‐substrate interactions and can be utilized as a primary filter to eliminate the potential selective inhibitor of CYP2B6. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2009
Investigation of chemical bond characteristics, thermal expansion coefficients and bulk moduli of α‐R2MoO6 and R2Mo2O7 (R = rare earths) by using a dielectric chemical bond method
Authors: Li Huaiyong , Zhang Siyuan , Zhou Shihong , Cao Xueqiang
Published: December 2008

Theoretical researches are performed on the α‐R2MoO6 (R = Y, Gd, Tb Dy, Ho, Er, Tm and Yb) and pyrochlore‐type R2Mo2O7 (R = Y, Nd, Sm, Gd, Tb and Dy) rare earth molybdates by using chemical bond theory of dielectric description. The chemical bonding characteristics and their relationship with thermal expansion property and compressibility are explored. The calculated values of linear thermal expansion coefficient (LTEC) and bulk modulus agree well with the available experimental values. The calculations reveal that the LTECs and the bulk moduli do have linear relationship with the ionic radii of the lanthanides: the LTEC decreases from 6.80 to 6.62 10−6/K and the bulk modulus increases from 141 to 154 GPa when R goes in the order Gd, Tb Dy, Ho, Er, Tm, and Yb in the α‐R2MoO6 series; while in the R2Mo2O7 series, the LTEC ranges from 6.80 to 6.61 10−6/K and the bulk modulus ranges from 147 to 163 GPa when R varies in the order Nd, Sm, Gd, Tb and Dy. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2009
Genome based cell population heterogeneity promotes tumorigenicity: The evolutionary mechanism of cancer
Authors: Ye Christine J. , Stevens Joshua B. , Liu Guo , Bremer Steven W. , Jaiswal Aruna S. , Ye Karen J. , Lin Ming‐Fong , Lawrenson Lesley , Lancaster Wayne D. , Kurkinen Markku , Liao Joshua D. , Gairola C. Gary , Shekhar Malathy P.V. , Narayan Satya , Miller Fred R. , Heng Henry H.Q.
Published: December 2008

Cancer progression represents an evolutionary process where overall genome level changes reflect system instability and serve as a driving force for evolving new systems. To illustrate this principle it must be demonstrated that karyotypic heterogeneity (population diversity) directly contributes to tumorigenicity. Five well characterized in vitro tumor progression models representing various types of cancers were selected for such an analysis. The tumorigenicity of each model has been linked to different molecular pathways, and there is no common molecular mechanism shared among them. According to our hypothesis that genome level heterogeneity is a key to cancer evolution, we expect to reveal that the common link of tumorigenicity between these diverse models is elevated genome diversity. Spectral karyotyping (SKY) was used to compare the degree of karyotypic heterogeneity displayed in various sublines of these five models. The cell population diversity was determined by scoring type and frequencies of clonal and non‐clonal chromosome aberrations (CCAs and NCCAs). The tumorigenicity of these models has been separately analyzed. As expected, the highest level of NCCAs was detected coupled with the strongest tumorigenicity among all models analyzed. The karyotypic heterogeneity of both benign hyperplastic lesions and premalignant dysplastic tissues were further analyzed to support this conclusion. This common link between elevated NCCAs and increased tumorigenicity suggests an evolutionary causative relationship between system instability, population diversity, and cancer evolution. This study reconciles the difference between evolutionary and molecular mechanisms of cancer and suggests that NCCAs can serve as a biomarker to monitor the probability of cancer progression. J. Cell. Physiol. 219: 288–300, 2009. © 2008 Wiley‐Liss, Inc.
The relative potency and safety of endothelial progenitor cells and unselected mononuclear cells for recovery from myocardial infarction and ischemia
Authors: Sekiguchi Haruki , II Masaaki , Losordo Douglas W.
Published: December 2008

Endothelial progenitor cells (EPCs) are a subset of the total mononuclear cell population (tMNCs) that possess an enhanced potential for differentiation within the endothelial‐cell lineage. Typically, EPCs are selected from tMNCs via the expression of both hematopoietic stem‐cell markers and endothelial‐cell markers, such as CD34, or by culturing tMNCs in media selective for endothelial cells. Both EPCs and tMNCs participate in vascular growth and regeneration, and their potential use for treatment of myocardial injury or disease has been evaluated in early‐phase clinical studies. Direct comparisons between EPCs and tMNCs are rare, but the available evidence appears to favor EPCs, particularly CD34+ cells, and the potency of EPCs may be increased as much as 30‐fold through genetic modification. However, these observations must be interpreted with caution because clinical investigations of EPC therapy are ongoing. We anticipate that with continued development, EPC therapy will become a safe and effective treatment option for patients with acute myocardial infarction or chronic ischemic disease. J. Cell. Physiol. 219: 235–242, 2009. © 2008 Wiley‐Liss, Inc.