Akt activation preserves cardiac function and prevents injury after transient cardiac ischemia in vivo

BACKGROUND

The serine-threonine kinase Akt is activated by several ligand-receptor systems previously shown to be cardioprotective. Akt activation reduces cardiomyocyte apoptosis in models of transient ischemia. Its role in cardiac dysfunction or infarction, however, remains unclear.

METHODS AND RESULTS

We examined the effects of a constitutively active Akt mutant (myr-Akt) in a rat model of cardiac ischemia-reperfusion injury. In vivo gene transfer of myr-Akt reduced infarct size by 64% and the number of apoptotic cells by 84% (P<0.005 for each). Ischemia-reperfusion injury decreased regional cardiac wall thickening as well as the maximal rate of left ventricular pressure rise and fall (+dP/dt and -dP/dt). Akt activation restored regional wall thickening and +dP/dt and -dP/dt to levels seen in sham-operated rats. To better understand this benefit, we examined the effects of myr-Akt on hypoxic cardiomyocyte dysfunction in vitro. myr-Akt prevented hypoxia-induced abnormalities in cardiomyocyte calcium transients and shortening. Akt activation also enhanced sarcolemmal expression of Glut-4 in vivo and increased glucose uptake in vitro to the level seen with insulin treatment.

CONCLUSIONS

Akt activation exerts a powerful cardioprotective effect after transient ischemia that probably reflects its ability to both inhibit cardiomyocyte death and improve function of surviving cardiomyocytes. Akt may represent an important nodal target for therapy in ischemic and other heart disease.

Structural basis for double-sieve discrimination of L-valine from L-isoleucine and L-threonine by the complex of tRNA(Val) and valyl-tRNA synthetase

Valyl-tRNA synthetase (ValRS) strictly discriminates the cognate L-valine from the larger L-isoleucine and the isosteric L-threonine by the tRNA-dependent "double sieve" mechanism. In this study, we determined the 2.9 A crystal structure of a complex of Thermus thermophilus ValRS, tRNA(Val), and an analog of the Val-adenylate intermediate. The analog is bound in a pocket, where Pro(41) allows accommodation of the Val and Thr moieties but precludes the Ile moiety (the first sieve), on the aminoacylation domain. The editing domain, which hydrolyzes incorrectly synthesized Thr-tRNA(Val), is bound to the 3' adenosine of tRNA(Val). A contiguous pocket was found to accommodate the Thr moiety, but not the Val moiety (the second sieve). Furthermore, another Thr binding pocket for Thr-adenylate hydrolysis was suggested on the editing domain.

Coordination-dependent surface atomic contraction in nanocrystals revealed by coherent diffraction

Surface atoms have fewer interatomic bonds than those in the bulk that they often relax and reconstruct on extended two-dimensional surfaces. Far less is known about the surface structures of nanocrystals. Here, we show that coherent diffraction patterns recorded from individual nanocrystals are very sensitive to the atomic structure of nanocrystal surfaces. Nanocrystals of Au of 3-5 nm in diameter were studied by examining diffraction intensity oscillations around the Bragg peaks. Both results obtained from modelling the experimental data and molecular dynamics simulations strongly suggest inhomogeneous relaxations, involving large out-of-plane bond length contractions for the edge atoms (approximately 0.2 A); a significant contraction (approximately 0.13 A) for {100} surface atoms; and a much smaller contraction (approximately 0.05 A) for atoms in the middle of the {111} facets. These results denote a coordination/facet dependence that markedly differentiates the structural dynamics of nanocrystals from bulk crystalline surfaces.

Prevalence of myocardial infarction in patients with psoriasis in central China

OBJECTIVE

To explore whether the prevalence of myocardial infarction (MI) was higher in psoriatics than in patients without psoriasis, and whether major cardiovascular risk factors were associated with psoriasis in central China.

METHODS

Data were collected at Medical Records Section of Affiliated Union Hospital, Tongji Hospital, Wuhan Iron and Steel Company General Hospital and No. 1 Hospital of Wuhan between 1999 and 2007. Patients with psoriasis were classified as severe if they ever received a systemic therapy. And patients were classified as having risk factors if they received codes for diabetes, hypertension, hyperlipidemia, or smoking. Controls without psoriasis were randomly selected from the Physical Examination Centre in the Affiliated Union Hospital. Analysis was performed by using conditional logistic regression, and adjustments were made for age and sex.

RESULTS

There were 45 MIs (2.96%) within the control population and 97 (6.00%) and 118 (8.01%) MIs within the mild and severe psoriasis groups, respectively. Respective odds ratio (OR) and 95% confidence interval (95% CI) of cardiovascular risk factors in those with mild psoriasis than controls were as follows: obesity (OR, 1.41; 95% CI, 1.08-1.85), diabetes (OR, 1.45; 95% CI, 1.11-1.91), hypertension (OR, 1.39; 95% CI, 1.04-1.85), hyperlipidemia (OR, 1.37; 95% CI, 1.06-1.78) and smoking (OR, 1.35; 95% CI, 1.01-1.80). Patients with severe psoriasis had higher adjusted odds of obesity (OR, 1.51; 95% CI, 1.15-1.98), diabetes (OR, 1.69; 95% CI, 1.32-2.17), hypertension (OR, 1.41; 95% CI, 1.06-1.88), hyperlipidemia (OR, 1.43; 95% CI, 1.11-1.84), and smoking (OR, 1.57; 95% CI, 1.20-2.05) than patients with mild psoriasis and controls. After adjusting for systemic therapies and cardiovascular risk factors (obesity, diabetes, hypertension, hyperlipidemia and smoking) in addition to age and sex, for patients with mild or severe psoriasis, the OR of having an MI was 1.72 (95% CI, 1.29-2.30) and 2.01 (95% CI, 1.45-2.79), respectively.

CONCLUSIONS

The prevalence of MI is higher in mild and severe psoriasis than in patients without psoriasis in central China. In addition, MI and major cardiovascular risk factors (e.g. diabetes, hypertension, hyperlipidemia and smoking) are associated with psoriasis in central China.

Platelet microparticles bind, activate and aggregate neutrophils in vitro

The interaction of activated platelets with leukocytes are believed to play an important role in ischemic reperfusion injury and other thrombotic conditions. Upon activation, platelets shed platelet microparticles (PMP) and express activation markers CD62P expressed on activated platelets mediates adhesion of platelets to leukocytes, chiefly neutrophils, but little is known of the interaction of PMP isolated from stored platelets or thrombin activated platelets was incubated with leukocytes and binding assessed by flow cytometry. FITC-labeled alpha-CD41 was used to assess platelet material associated with WBC. Like platelets PMP bound preferentially to neutrophils rather than lymphocytes, and exhibited an absolute dependence on the presence of Ca2+. Binding was time-and concentration-dependent, reaching a plateau at 10 min at a ratio of PMP to neutrophils of 150:1. Fluorescence microscopy showed that most of the neutrophils were aggregated into clusters of 5-20 cells. Clustering of neutrophils was not observed to result form interaction with platelets. In these clusters the adherent PMP appeared to serve as bridges between the neutrophil. Addition of EGTA after brief incubation (5-10 min) released most of the bound PMP but if added after > 10 min, only approximately 60% of bound PMP were released. In contrast, nearly all bound platelets were released by EGTA at the same time of incubation. Incubation of neutrophils with PMP gave significantly higher percentage of CD41a(+)neutrophils than did platelets incubated at the same numerical ratio. PMP association with neutrophils was less markedly inhibited by alpha-CD62P (AC1.2) than platelets, but binding of both PMP and activated platelets was inhibited approximately 90% by antisialyl Lewis X. PMP binding to neutrophils induced a significant increase in both CD11b expression and phagocytic activity in a concentration-dependent manner. These findings suggest a possible role for PMP in addition to providing platelet factor 3, specifically, as an activator and mediator of neutrophils in ischemic injury, thrombosis, and inflammation.

Cloning and functional analysis of cDNAs with open reading frames for 300 previously undefined genes expressed in CD34+ hematopoietic stem/progenitor cells

Three hundred cDNAs containing putatively entire open reading frames (ORFs) for previously undefined genes were obtained from CD34+ hematopoietic stem/progenitor cells (HSPCs), based on EST cataloging, clone sequencing, in silico cloning, and rapid amplification of cDNA ends (RACE). The cDNA sizes ranged from 360 to 3496 bp and their ORFs coded for peptides of 58-752 amino acids. Public database search indicated that 225 cDNAs exhibited sequence similarities to genes identified across a variety of species. Homology analysis led to the recognition of 50 basic structural motifs/domains among these cDNAs. Genomic exon-intron organization could be established in 243 genes by integration of cDNA data with genome sequence information. Interestingly, a new gene named as HSPC070 on 3p was found to share a sequence of 105bp in 3' UTR with RAF gene in reversed transcription orientation. Chromosomal localizations were obtained using electronic mapping for 192 genes and with radiation hybrid (RH) for 38 genes. Macroarray technique was applied to screen the gene expression patterns in five hematopoietic cell lines (NB4, HL60, U937, K562, and Jurkat) and a number of genes with differential expression were found. The resource work has provided a wide range of information useful not only for expression genomics and annotation of genomic DNA sequence, but also for further research on the function of genes involved in hematopoietic development and differentiation.

Specific binding of arginine to TAR RNA

A single arginine residue within the basic region of the human immunodeficiency virus Tat protein mediates specific binding of Tat peptides to a three-nucleotide bulge in TAR RNA. It has been proposed that arginine recognizes TAR by forming a network of hydrogen bonds with two structurally distinct phosphates, an interaction termed the "arginine fork." Here it is shown that L-arginine blocks the Tat peptide/TAR interaction, whereas L-lysine and analogs of arginine that remove specific hydrogen bond donors do not. Experiments using an L-arginine affinity column demonstrate that arginine and the Tat peptides bind to the same site in TAR. Modification of two phosphates located at the junction of the double-stranded stem and bulge and modification of two adenine N7 groups in base-paired regions of TAR interfere with specific arginine binding. The results emphasize the importance of RNA structure in RNA-protein recognition and provide methods to identify arginine-binding sites in RNAs.

Role of NF-kappaB in the antiproliferative effect of endothelin-1 and tumor necrosis factor-alpha in human hepatic stellate cells. Involvement of cyclooxygenase-2

During chronic liver diseases, hepatic stellate cells (HSC) acquire an activated myofibroblast-like phenotype and proliferate and synthesize fibrosis components. Endothelin-1 (ET-1), which inhibited the growth of human myofibroblastic HSC, increased the formation of two NF-kappaB DNA binding complexes; this effect was also observed with tumor necrosis factor-alpha (TNF-alpha). The complexes were identified as the p50/p50 and p50/p65 NF-kappaB dimers. Activation of NF-kappaB was associated with the degradation of the inhibitory protein IkappaB-alpha; no IkappaB-beta was detected. Activation of NF-kappaB and degradation of IkappaB-alpha were prevented by the NF-kappaB inhibitors sodium salicylate and MG-132. In addition to cyclooxygenase-1 (COX-1), COX-2 is also constitutively expressed in human HSC, and the use of dexamethasone and of SC-58125, a selective COX-2 inhibitor, revealed that COX-2 accounts for basal COX activity. Moreover, COX-2 mRNA and protein were up-regulated by ET-1 and TNF-alpha, whereas COX-1 was unaffected. Induction of COX-2 and stimulation of COX activity by ET-1 and TNF-alpha were prevented by sodium salicylate and MG-132, suggesting that activation of NF-kappaB by either factor is needed for stimulation of COX-2. Finally, SC-58125 and dexamethasone reduced the growth inhibitory effect of ET-1 and TNF-alpha, indicating that activation of COX-2 is required for inhibition of HSC proliferation. Taken together, our results suggest that NF-kappaB, by inducing COX-2 expression, may play an important role in the negative regulation of human myofibroblastic HSC proliferation.

John J, Sulak L, Zou D, Alimena J, Berry E, Bhattacharya S, Cutts D, Dhingra N, Ferapontov A, Garabedian A, Hakala J, Heintz U, Laird E, Landsberg G, Mao Z, Narain M, Piperov S, Sagir S, Syarif R, Breedon R, Breto G, De La Barca Sanchez MC, Chauhan S, Chertok M, Conway J, Conway R, Cox PT, Erbacher R, Funk G, Gardner M, Ko W, Lander R, Mulhearn M, Pellett D, Pilot J, Ricci-Tam F, Shalhout S, Smith J, Squires M, Stolp D, Tripathi M, Wilbur S, Yohay R, Bravo C, Cousins R, Everaerts P, Farrell C, Florent A, Hauser J, Ignatenko M, Saltzberg D, Schnaible C, Valuev V, Weber M, Burt K, Clare R, Ellison J, Gary JW, Hanson G, Heilman J, Ivova PANEVA M, Jandir P, Kennedy E, Lacroix F, Long OR, Luthra A, Malberti M, Negrete MO, Shrinivas A, Wei H, Wimpenny S, Yates BR, Branson JG, Cerati GB, Cittolin S, D’Agnolo RT, Derdzinski M, Holzner A, Kelley R, Klein D, Letts J, Macneill I, Olivito D, Padhi S, Pieri M, Sani M, Sharma V, Simon S, Tadel M, Tu Y, Vartak A, Wasserbaech S, Welke C, Würthwein F, Yagil A, Zevi Della Porta G, Bradmiller-Feld J, Campagnari C, Dishaw A, Dutta V, Flowers K, Franco Sevilla M, Geffert P, George C, Golf F, Gouskos L, Gran J, Incandela J, Mccoll N, Mullin SD, Mullin SD, Richman J, Stuart D, Suarez I, West C, Yoo J, Anderson D, Apresyan A, Bornheim A, Bunn J, Chen Y, Duarte J, Mott A, Newman HB, Pena C, Pierini M, Spiropulu M, Vlimant JR, Xie S, Zhu RY, Andrews MB, Azzolini V, Calamba A, Carlson B, Ferguson T, Paulini M, Russ J, Sun M, Vogel H, Vorobiev I, Cumalat JP, Ford WT, Gaz A, Jensen F, Johnson A, Krohn M, Mulholland T, Nauenberg U, Stenson K, Wagner SR, Alexander J, Chatterjee A, Chaves J, Chu J, Dittmer S, Eggert N, Mirman N, Nicolas Kaufman G, Patterson JR, Rinkevicius A, Ryd A, Skinnari L, Soffi L, Sun W, Tan SM, Teo WD, Thom J, Thompson J, Tucker J, Weng Y, Wittich P, Abdullin S, Albrow M, Apollinari G, Banerjee S, Bauerdick LAT, Beretvas A, Berryhill J, Bhat PC, Bolla G, Burkett K, Butler JN, Cheung HWK, Chlebana F, Cihangir S, Elvira VD, Fisk I, Freeman J, Gottschalk E, Gray L, Green D, Grünendahl S, Gutsche O, Hanlon J, Hare D, Harris RM, Hasegawa S, Hirschauer J, Hu Z, Jayatilaka B, Jindariani S, Johnson M, Joshi U, Jung AW, Klima B, Kreis B, Lammel S, Linacre J, Lincoln D, Lipton R, Liu T, Lopes De Sá R, Lykken J, Maeshima K, Marraffino JM, Martinez Outschoorn VI, Maruyama S, Mason D, McBride P, Merkel P, Mishra K, Mrenna S, Nahn S, Newman-Holmes C, O’Dell V, Pedro K, Prokofyev O, Rakness G, Sexton-Kennedy E, Soha A, Spalding WJ, Spiegel L, Strobbe N, Taylor L, Tkaczyk S, Tran NV, Uplegger L, Vaandering EW, Vernieri C, Verzocchi M, Vidal R, Weber HA, Whitbeck A, Acosta D, Avery P, Bortignon P, Bourilkov D, Carnes A, Carver M, Curry D, Das S, Field RD, Furic IK, Gleyzer SV, Hugon J, Konigsberg J, Korytov A, Kotov K, Low JF, Ma P, Matchev K, Mei H, Milenovic P, Mitselmakher G, Rank D, Rossin R, Shchutska L, Snowball M, Sperka D, Terentyev N, Thomas L, Wang J, Wang S, Yelton J, Hewamanage S, Linn S, Markowitz P, Martinez G, Rodriguez JL, Adams JR, Ackert A, Adams T, Askew A, Bein S, Bochenek J, Diamond B, Haas J, Hagopian S, Hagopian V, Johnson KF, Khatiwada A, Prosper H, Weinberg M, Baarmand MM, Bhopatkar V, Colafranceschi S, Hohlmann M, Kalakhety H, Noonan D, Roy T, Yumiceva F, Adams MR, Apanasevich L, Berry D, Betts RR, Bucinskaite I, Cavanaugh R, Evdokimov O, Gauthier L, Gerber CE, Hofman DJ, Kurt P, O’Brien C, Sandoval Gonzalez LD, Silkworth C, Turner P, Varelas N, Wu Z, Zakaria M, Bilki B, Clarida W, Dilsiz K, Durgut S, Gandrajula RP, Haytmyradov M, Khristenko V, Merlo JP, Mermerkaya H, Mestvirishvili A, Moeller A, Nachtman J, Ogul H, Onel Y, Ozok F, Penzo A, Snyder C, Tiras E, Wetzel J, Yi K, Anderson I, Anderson I, Barnett BA, Blumenfeld B, Eminizer N, Fehling D, Feng L, Gritsan AV, Maksimovic P, Martin C, Osherson M, Roskes J, Sady A, Sarica U, Swartz M, Xiao M, Xin Y, You C, Xiao M, Baringer P, Bean A, Benelli G, Bruner C, Kenny RP, Majumder D, Majumder D, Malek M, Murray M, Sanders S, Stringer R, Wang Q, Ivanov A, Kaadze K, Khalil S, Makouski M, Maravin Y, Mohammadi A, Saini LK, Skhirtladze N, Toda S, Lange D, Rebassoo F, Wright D, Anelli C, Baden A, Baron O, Belloni A, Calvert B, Eno SC, Ferraioli C, Gomez JA, Hadley NJ, Jabeen S, Jabeen S, Kellogg RG, Kolberg T, Kunkle J, Lu Y, Mignerey AC, Shin YH, Skuja A, Tonjes MB, Tonwar SC, Apyan A, Barbieri R, Baty A, Bierwagen K, Brandt S, Bierwagen K, Busza W, Cali IA, Demiragli Z, Di Matteo L, Gomez Ceballos G, Goncharov M, Gulhan D, Iiyama Y, Innocenti GM, Klute M, Kovalskyi D, Lai YS, Lee YJ, Levin A, Luckey PD, Marini AC, Mcginn C, Mironov C, Narayanan S, Niu X, Paus C, Ralph D, Roland C, Roland G, Salfeld-Nebgen J, Stephans GSF, Sumorok K, Varma M, Velicanu D, Veverka J, Wang J, Wang TW, Wyslouch B, Yang M, Zhukova V, Dahmes B, Evans A, Finkel A, Gude A, Hansen P, Kalafut S, Kao SC, Klapoetke K, Kubota Y, Lesko Z, Mans J, Nourbakhsh S, Ruckstuhl N, Rusack R, Tambe N, Turkewitz J, Acosta JG, Oliveros S, Avdeeva E, Bloom K, Bose S, Claes DR, Dominguez A, Fangmeier C, Gonzalez Suarez R, Kamalieddin R, Keller J, Knowlton D, Kravchenko I, Meier F, Monroy J, Ratnikov F, Siado JE, Snow GR, Alyari M, Dolen J, George J, Godshalk A, Harrington C, Iashvili I, Kaisen J, Kharchilava A, Kumar A, Rappoccio S, Roozbahani B, Alverson G, Barberis E, Baumgartel D, Chasco M, Hortiangtham A, Massironi A, Morse DM, Nash D, Orimoto T, Teixeira De Lima R, Trocino D, Wang RJ, Wood D, Zhang J, Hahn KA, Kubik A, Mucia N, Odell N, Pollack B, Pozdnyakov A, Schmitt M, Stoynev S, Sung K, Trovato M, Velasco M, Brinkerhoff A, Dev N, Hildreth M, Jessop C, Karmgard DJ, Kellams N, Lannon K, Marinelli N, Meng F, Mueller C, Musienko Y, Planer M, Reinsvold A, Ruchti R, Smith G, Taroni S, Valls N, Wayne M, Wolf M, Woodard A, Antonelli L, Brinson J, Bylsma B, Durkin LS, Flowers S, Hart A, Hill C, Hughes R, Ji W, Ling TY, Liu B, Luo W, Puigh D, Rodenburg M, Winer BL, Wulsin HW, Driga O, Elmer P, Hardenbrook J, Hebda P, Koay SA, Lujan P, Marlow D, Medvedeva T, Mooney M, Olsen J, Palmer C, Piroué P, Saka H, Stickland D, Tully C, Zuranski A, Malik S, Barnes VE, Benedetti D, Bortoletto D, Gutay L, Jha MK, Jones M, Jung K, Miller DH, Neumeister N, Primavera F, Radburn-Smith BC, Shi X, Shipsey I, Silvers D, Sun J, Svyatkovskiy A, Wang F, Xie W, Xu L, Parashar N, Stupak J, Adair A, Akgun B, Chen Z, Ecklund KM, Geurts FJM, Guilbaud M, Li W, Michlin B, Northup M, Padley BP, Redjimi R, Roberts J, Rorie J, Tu Z, Zabel J, Betchart B, Bodek A, de Barbaro P, Demina R, Eshaq Y, Ferbel T, Galanti M, Galanti M, Garcia-Bellido A, Han J, Harel A, Hindrichs O, Hindrichs O, Khukhunaishvili A, Petrillo G, Tan P, Verzetti M, Arora S, Barker A, Chou JP, Contreras-Campana C, Contreras-Campana E, Ferencek D, Gershtein Y, Gray R, Halkiadakis E, Hidas D, Hughes E, Kaplan S, Kunnawalkam Elayavalli R, Lath A, Nash K, Panwalkar S, Park M, Salur S, Schnetzer S, Sheffield D, Somalwar S, Stone R, Thomas S, Thomassen P, Walker M, Foerster M, Riley G, Rose K, Spanier S, York A, Bouhali O, Castaneda Hernandez A, Celik A, Dalchenko M, De Mattia M, Delgado A, Dildick S, Dildick S, Eusebi R, Gilmore J, Huang T, Kamon T, Krutelyov V, Krutelyov V, Mueller R, Osipenkov I, Pakhotin Y, Patel R, Patel R, Perloff A, Rose A, Safonov A, Tatarinov A, Ulmer KA, Akchurin N, Cowden C, Damgov J, Dragoiu C, Dudero PR, Faulkner J, Kunori S, Lamichhane K, Lee SW, Libeiro T, Undleeb S, Volobouev I, Appelt E, Delannoy AG, Greene S, Gurrola A, Janjam R, Johns W, Maguire C, Mao Y, Melo A, Ni H, Sheldon P, Snook B, Tuo S, Velkovska J, Xu Q, Arenton MW, Cox B, Francis B, Goodell J, Hirosky R, Ledovskoy A, Li H, Lin C, Neu C, Sinthuprasith T, Sun X, Wang Y, Wolfe E, Wood J, Xia F, Clarke C, Harr R, Karchin PE, Kottachchi Kankanamge Don C, Lamichhane P, Sturdy J, Belknap DA, Carlsmith D, Cepeda M, Dasu S, Dodd L, Duric S, Gomber B, Grothe M, Hall-Wilton R, Herndon M, Hervé A, Klabbers P, Lanaro A, Levine A, Long K, Loveless R, Mohapatra A, Ojalvo I, Perry T, Pierro GA, Polese G, Ruggles T, Sarangi T, Savin A, Sharma A, Smith N, Smith WH, Taylor D, Woods N. Event generator tunes obtained from underlying event and multiparton scattering measurements

New sets of parameters ("tunes") for the underlying-event (UE) modelling of the pythia8, pythia6 and herwig++ Monte Carlo event generators are constructed using different parton distribution functions. Combined fits to CMS UE proton-proton ([Formula: see text]) data at [Formula: see text] and to UE proton-antiproton ([Formula: see text]) data from the CDF experiment at lower [Formula: see text], are used to study the UE models and constrain their parameters, providing thereby improved predictions for proton-proton collisions at 13[Formula: see text]. In addition, it is investigated whether the values of the parameters obtained from fits to UE observables are consistent with the values determined from fitting observables sensitive to double-parton scattering processes. Finally, comparisons are presented of the UE tunes to "minimum bias" (MB) events, multijet, and Drell-Yan ([Formula: see text] lepton-antilepton+jets) observables at 7 and 8[Formula: see text], as well as predictions for MB and UE observables at 13[Formula: see text].

15-deoxy-Delta 12,14-prostaglandin J2 induces apoptosis of human hepatic myofibroblasts. A pathway involving oxidative stress independently of peroxisome-proliferator-activated receptors

Hepatic myofibroblasts (hMFs) play a key role in the development of liver fibrosis associated with chronic liver diseases. Apoptosis of these cells is emerging as a key process in the resolution of liver fibrosis. Here, we examined the effects of cyclopentenone prostaglandins on apoptosis of human hMFs. Cyclopentenone prostaglandins of the J series markedly reduced hMF viability, with 15-deoxy-Delta(12,14)-prostaglandin J2 (15-d-PGJ2) being the most potent. This effect was independent of peroxisome-proliferator-activated receptors (PPARs), because PPARgamma and PPARalpha agonists did not affect hMF cell viability, and PPARgamma, the nuclear receptor for 15-d-PGJ2, was not expressed in hMFs. Moreover, 15-d-PGJ2 did not act via a cell surface G protein-coupled receptor, as shown in guanosine-5'-O-(3-thiotriphosphate) binding assays. Cell death resulted from an apoptotic process, because 15-d-PGJ2-treated hMFs exhibited condensed nuclei, fragmented DNA, and elevated caspase-3 activity. Moreover, the caspase inhibitor Z-Val-Ala-Asp(OCH3)-fluoromethyl ketone blocked the cytotoxic effect of 15-d-PGJ2. The apoptotic effects of 15-d-PGJ2 were reproduced by H2O2 and blocked by the antioxidants N-acetylcysteine (NAC), N-(2-mercapto-propionyl)-glycine (NMPG) and pyrrolidine dithiocarbamate (PDTC). Accordingly, 15-d-PGJ2 generated rapid production of reactive oxygen species in hMFs, via a NAC/NMPG/PDTC-sensitive pathway. In conclusion, 15-d-PGJ2 induces apoptosis of human hMFs via a novel mechanism involving oxidative stress and unrelated to activation of its nuclear receptor PPARgamma. These data underline the antifibrogenic potential of 15-d-PGJ2.

Tetragonal-to-orthorhombic structural phase transition at 90 K in the superconductor Fe(1.01)Se

In this Letter we show that superconducting Fe(1.01)Se undergoes a structural transition at 90 K from a tetragonal to an orthorhombic phase but that nonsuperconducting Fe(1.03)Se does not. High resolution electron microscopy at low temperatures further reveals an unexpected additional modulation of the crystal structure of the superconducting phase that involves displacements of the Fe atoms, and that the nonsuperconducting composition shows a different, complex nanometer-scale structural modulation. Finally, we show that magnetism is not the driving force for the phase transition in the superconducting phase.

Antiproliferative properties of sphingosine 1-phosphate in human hepatic myofibroblasts. A cyclooxygenase-2 mediated pathway

Proliferation of hepatic myofibroblasts (hMF) is central for the development of fibrosis during liver injury, and factors that may limit their growth are potential antifibrotic agents. Sphingosine 1-phosphate (S1P) is a bioactive sphingolipid with growth-regulating properties, either via Edg receptors or through intracellular actions. In this study, we examined the effects of S1P on the proliferation of human hMF. Human hMF expressed mRNAs for the S1P receptors Edg1, Edg3, and Edg5. These receptors were functional at nanomolar concentrations and coupled to pertussis toxin-sensitive and -insensitive G proteins, as demonstrated in guanosine 5'-3-O-(thio)triphosphate binding assays. S1P potently inhibited hMF growth (IC(50) = 1 microm), in a pertussis toxin-insensitive manner. Analysis of the mechanisms involved in growth inhibition revealed that S1P rapidly increased prostaglandin E(2) production and in turn cAMP, two growth inhibitory messengers for hMF; C(2)-ceramide and sphingosine, which inhibited hMF proliferation, did not affect cAMP levels. Production of cAMP by S1P was abolished by NS-398, a selective inhibitor of COX-2. Also, S1P potently induced COX-2 protein expression. Blocking COX-2 by NS-398 blunted the antiproliferative effect of S1P. We conclude that S1P inhibits proliferation of hMF, probably via an intracellular mechanism, through early COX-2-dependent release of prostaglandin E(2) and cAMP, and delayed COX-2 induction. Our results shed light on a novel role for S1P as a growth inhibitory mediator and point out its potential involvement in the negative regulation of liver fibrogenesis.

Stimulation of stress-activated protein kinase and p38 HOG1 kinase in murine keratinocytes following photodynamic therapy with benzoporphyrin derivative

The activation state of the members of the mitogen-activated protein kinase family following photodynamic therapy (PDT) with benzoporphyrin derivative monoacid ring A was investigated using a naturally transformed murine keratinocyte cell line, Pam 212. PDT involves the use of photosensitizer molecules and a specific wavelength of visible light. The process of PDT generates singlet oxygen and other reactive oxygen intermediates (ROIs), and the cytotoxic effect of these ROIs is the basis for the use of PDT to treat cancer and psoriasis. PDT caused a strong dose- and time-dependent activation of both stress-activated protein kinase (SAPK) and p38 HOG1. The maximum activation of SAPK and p38 HOG1 occurred between 20 and 30 min following PDT treatment with 200 ng/ml benzoporphyrin derivative monoacid ring A and 2 J/cm2 of red light at 690 nm. In our system, PDT did not cause significant activation of extracellularly regulated kinase (ERK) 1 and ERK2. Under the same experimental conditions, ultraviolet light irradiation caused strong activation of SAPK and p38 HOG1 and minimum activation of ERK1 and ERK2 in Pam212 cells. A number of ROI scavengers were tested for their effect on PDT-induced SAPK and p38 HOG1 activation. Both L-histidine and N-acetyl-L-cysteine showed a significant inhibitory effect on PDT-induced SAPK and p38 HOG1 activation. This indicated that PDT-induced SAPK and p38 HOG1 activation may be partially mediated by ROI.

Platelet-derived growth factor-BB and thrombin generate positive and negative signals for human hepatic stellate cell proliferation. Role of a prostaglandin/cyclic AMP pathway and cross-talk with endothelin receptors

Proliferation of myofibroblastic hepatic stellate cells (HSC) in response to growth factors is essential for the development of liver fibrosis. We have reported that prostaglandins (PG) and cyclic AMP (cAMP) inhibit growth of human HSC. This PG/cAMP pathway transduces the endothelin (ET) B-mediated antiproliferative effect of endothelin-1 (ET-1) and up-regulates ETB receptors. Here, we show that platelet-derived growth factor (PDGF)-BB and thrombin, although mitogenic, generate growth inhibitory PGE2 in myofibroblastic human HSC. The two peptides elicit early PGE2 and cAMP synthesis, and also promote delayed induction of cyclooxygenase (COX)-2. Both early and delayed production of PGE2 counteract the mitogenic effect of PDGF-BB and thrombin because: (i) pretreatment with the COX inhibitor ibuprofen markedly enhances the mitogenic effect of both peptides; (ii) blocking early synthesis of PGE2 greatly enhances extracellular signal-regulated kinase (ERK) activation by both growth factors; (iii) enhancement of DNA synthesis by ibuprofen is only lost when the inhibitor is added after COX-2 induction has occurred. Finally, PDGF-BB and thrombin raise ETB receptors through the PG pathway. Thus, ibuprofen blunts growth factor-induced increase in ETB receptors. Up-regulation of the growth inhibitory ETB receptors by both mitogens may enhance the antiproliferative effect of ET-1 and thereby establish a negative feedback of their mitogenic effect. Our results shed light on novel growth inhibitory signals evoked by two mitogenic growth factors expressed during liver injury.

Extraction and validation of a new set of CMS pythia8 tunes from underlying-event measurements

New sets of CMS underlying-event parameters ("tunes") are presented for the pythia8 event generator. These tunes use the NNPDF3.1 parton distribution functions (PDFs) at leading (LO), next-to-leading (NLO), or next-to-next-to-leading (NNLO) orders in perturbative quantum chromodynamics, and the strong coupling evolution at LO or NLO. Measurements of charged-particle multiplicity and transverse momentum densities at various hadron collision energies are fit simultaneously to determine the parameters of the tunes. Comparisons of the predictions of the new tunes are provided for observables sensitive to the event shapes at LEP, global underlying event, soft multiparton interactions, and double-parton scattering contributions. In addition, comparisons are made for observables measured in various specific processes, such as multijet, Drell-Yan, and top quark-antiquark pair production including jet substructure observables. The simulation of the underlying event provided by the new tunes is interfaced to a higher-order matrix-element calculation. For the first time, predictions from pythia8 obtained with tunes based on NLO or NNLO PDFs are shown to reliably describe minimum-bias and underlying-event data with a similar level of agreement to predictions from tunes using LO PDF sets.

Rapid induction of cAMP/PKA pathway during retinoic acid-induced acute promyelocytic leukemia cell differentiation

The second messenger cyclic adenosine monophosphate (cAMP) plays an important role in cell proliferation, differentiation and apoptosis. In the present work, we evaluated the cAMP signaling in acute promyelocytic leukemia (APL) cells in the context of differentiation induced by all-trans retinoic acid (ATRA). There was a marked increase in the intracellular cAMP level within a few minutes after treatment with ATRA in APL cell line NB4 and fresh APL cells, whereas no such phenomenon was observed in NB4-R1 cells that are resistant to ATRA-induced maturation. In addition, the basal level of intracellular cAMP was lower in NB4-R1 than in NB4 cells. Mechanistic study showed that this induction of cAMP was mediated through the activation of adenylate cyclase. Moreover, we found that cAMP-dependent protein kinase (PKA) activity was quickly upregulated in parallel in ATRA-treated NB4 cells, and the phosphorylation of RARalpha by PKA could increase its transactivation effect. Use of H-89, an inhibitor of PKA, could partially suppress the transcriptional expression of ATRA target genes and ATRA-induced differentiation of APL cells. Taken together, we suggested a crosstalk between ATRA-induced cytosolic pathway and nuclear pathway in APL cell differentiation.

Bone marrow stromal cells prevent apoptosis of lymphoma cells by upregulation of anti-apoptotic proteins associated with activation of NF-kappaB (RelB/p52) in non-Hodgkin's lymphoma cells

Stromal cells are an essential component of the bone marrow microenvironment that regulate or supports tumor survival. In this study we therefore studied the role of stromal cells in lymphoma cell survival. We demonstrated that adhesion of the B-cell lymphoma cell lines SUDH-4 and 10 to bone marrow stroma inhibited mitoxantrone-induced apoptosis. This adhesion-dependent inhibition of mitoxantrone-induced apoptosis correlated with decreased activation of caspases-8 and 9, and cleavage of caspase 3 and PARP. Electrophoretic mobility shift assays (EMSA) analysis demonstrated significantly increased NF-kappaB binding activity in lymphoma cells adhered to stroma cells compared to lymphoma cells in suspension. This DNA binding activity could be attributed to cell adhesion-mediated proteolysis of the NF-kappaB precursor, p100 (NF-kappaB2). This resulted in the generation of active p52, which translocated to the nucleus in complex with p65 and RelB. Coculture with stromal cells also induced expression of the NF-kappaB-regulated anti-apoptotic molecules, XIAP, cIAP(1) and cIAP(2). Inhibition of NF-kappaB significantly suppressed HS-5-induced protection against apoptosis in lymphoma cell lines as well as in primary lymphoma cells. Thus, bone marrow stroma protects B-cell lymphoma cells against apoptosis, at least in part through activation of NF-kappaB dependent mechanism involving up-regulation of NF-kappaB regulated antiapoptotic proteins. Consequently, this study suggests a new approach to decrease the resistance of lymphoma to chemotherapy.

Electrostatic interactions modulate the RNA-binding and transactivation specificities of the human immunodeficiency virus and simian immunodeficiency virus Tat proteins

The transcriptional activating (Tat) proteins from human immunodeficiency virus and simian immunodeficiency virus are sequence-specific RNA-binding proteins. In human immunodeficiency virus Tat, a single arginine residue, flanked on each side by three to four basic amino acids, mediates specific binding to a bulge region in trans-acting responsive element (TAR) RNA. We have systematically mutated the flanking charged residues and found that, in addition to the position of the sequence-specific arginine, the particular arrangement of nonspecific electrostatic interactions is an important determinant of RNA-binding specificity and transactivation activity. These additional electrostatic contacts may help stabilize the structure of TAR RNA when bound to arginine. One critical electrostatic interaction, located two residues N-terminal to the arginine, is absent in the simian immunodeficiency virus Tat protein and accounts for the difference in promoter specificities of the human and simian immunodeficiency viral proteins.

Osmotic properties of boar spermatozoa and their relevance to cryopreservation

A series of six experiments was conducted to determine the fundamental cryobiological properties of boar spermatozoa to develop optimal approaches for cryopreserving this important cell type. In the first experiments, boar spermatozoa samples were diluted in various osmolalities of experimental solutions (185-900 mOsmol kg-1) to provide hypo-, iso-, and hyperosmotic conditions. Equilibrium cell volumes (Expts 1 and 2) were measured after exposure for 3 min and the change in cell volume was measured over time using an electronic particle counter (Expt 3). The isosmotic cell volume was found to be 26.3 +/- 0.39 microns 3 (mean +/- SEM; n = 5). Over this range of osmolalities, boar spermatozoa behaved as linear osmometers (a linear volume versus 1/osm plot, r2 = 0.99) with an osmotically inactive cell fraction of 67.4 +/- 4.5%. The rate of water permeability (Lp) was determined to be 1.03 +/- 0.05 microns min-1 atm-1, which was consistent within and among donors (P > 0.130). A second series of experiments was performed to determine the effect of temperature and osmolality on boar sperm motility (Expt 4), and the effect of osmolality on the integrity of the sperm plasma membrane and its temperature dependence. Plasma membrane integrity was measured before and after boar spermatozoa were returned to an isosmolality (Expt 6). Motility was not affected at 30 degrees C, relative to that at room temperature, but was significantly decreased (P < 0.05) at 8 degrees C and 0 degree C (yielding a relative reduction to 85% and 35% of original motility, respectively; n = 6). Sperm motility was not significantly decreased (P > 0.05) until the osmolality reached 210 mOsmol kg-1, at which time motility began to decrease from 95% to 10% of the original value at 90 mOsmol kg-1. The integrity of the plasma membrane of boar spermatozoa was found to be dependent on temperature, donor and osmolality, decreasing significantly (P < 0.05) below room temperature, and below 185 mOsmol kg-1 (P < 0.05). There was no significant difference (P > 0.10) in the integrity of the plasma membrane of the samples before and after returning to 290 mOsmol kg-1, indicating that osmotic damage occurs during the initial change from isosmotic to hyposmotic media. These osmotic characteristics could be used to determine optimal conditions for cryopreservation of boar spermatozoa.