New insights into the expression and role of platelet FXIII-A

25 p.-6 fig.Background: The A subunit of factor XIII (FXIII-A) functions as an intracellular transglutaminase (TG) in the megakaryocyte/platelet lineage, where it probably participates in the cytoskeletal remodeling associated with cell activation. However, so far, the precise role of cellular FXIII (cFXIII) and the functional consequences of its absence in FXIII-A-deficient patients are unknown. Objectives and methods: In this study, we used platelets from four patients with congenital deficiency of FXIII-A to study the role of cFXIII in platelet functions. Results: We found that FXIII-A represents the only detectable source of TG activity in platelets and that the binding of fibrinogen in response to thrombin receptor agonist peptide (TRAP) stimulation was significantly reduced in platelets from the patients. In agreement with this, in control platelets, monodansyl-cadaverine (MDC), a competitive amino-donor for TGs, inhibited fibrinogen binding induced by TRAP in a dose-dependent manner. Moreover, upon adhesion to fibrinogen, normal platelets incubated with MDC as well as FXIII-A-deficient platelets showed a distinct extension pattern with reduced lamellipodia and increased filopodia formation, suggesting a delay in spreading. Conclusions: These findings provide evidence for the direct involvement of cFXIII-dependent TG activity in the regulation of platelet functionsThis work was supported by grants from the Dirección General de Investigación del Ministerio de Educación y Ciencia (BFU2006-00914) and Fundación Rodríguez Pascual. A. Jayo was recipient of a fellowship from the Ministerio de Educación y Ciencia. I. Conde holds a research contract from the Consejo Superior de Investigaciones Científica

Monoclinic polymorph of 2-(pyrimidin-2-ylsulfan­yl)acetic acid

The title compound, C6H6N2O2S, is a new polymorphic form of 2-(pyrimidin-2-ylsulfan­yl)acetic acid. Unlike the previous orthorhombic polymorph [Pan & Chen (2009 ▶) Acta Cryst. E65, o652], the mol­ecules are not planar: the aromatic ring makes an angle of 80.67 (17)° with the carboxyl plane. In the crystal, mol­ecules are linked by O—H⋯N hydrogen bonds into chains along [02]

Phenyl­hydrazinium (6-carb­oxy­pyridine-2-carboxyl­ato)(pyridine-2,6-dicarboxyl­ato)cobaltate(II)–pyridine-2,6-dicarb­oxy­lic acid–water (1/1/3)

The asymmetric unit of the title compound, (C6H9N2)[Co(C7H3NO4)(C7H4NO4)]·C7H5NO4·3H2O, contains one (6-carb­oxy­pyridine-2-carboxyl­ato)(pyridine-2,6-dicarboxyl­ato)cobaltate(II) anion, one phenyl­hydrazinium cation, one pyridine-2,6-dicarb­oxy­lic acid mol­ecule and three uncoordin­ated water mol­ecules, part of which are disordered. The CoII ion is coordinated by a pyridine-2,6-dicarboxyl­ate ion and a 6-carb­oxy­pyridine-2-carboxyl­ate ligand almost perpendicular to each other [the angle between the least-squares planes is 87.38 (4)°] and is surrounded by two O atoms and two N atoms in the equatorial plane and two O atoms in axial positions, resulting in a distorted octa­hedral coordination geometry. There is an extensive three-dimensional network of O—H⋯O and N—H⋯O hydrogen bonds, which link the components

Type II Glanzmann thrombasthenia in a compound heterozygote for the [alpha]IIb gene. A novel missense mutation in exon 27 that results in enhanced skipping of exon 28

8 páginas, 5 figuras -- PAGS nros. 1352-1359Background and Objectives. Glanzmann thrombasthenia is an autosomal recessive bleeding disorder characterized by a life-long hemorrhagic tendency and absent or severely reduced platelet aggregation in response to agonists, caused by quantitative or qualitative abnormalities in the platelet fibrinogen receptor, integrin αIIbβ3. The aim of this study was to identify the molecular genetic defect and determine its functional consequences in a patient with type II Glanzmann thrombasthenia. Design and Methods. The expression of platelet αIIbβ3 was determined by flow cytometry and western blotting. Mutations were identified by sequencing both cDNA and genomic DNA. Functional characterization was assessed by exontrap and transient transfection analysis. Results. Flow cytometry and western blot analysis revealed markedly reduced levels of platelet αIIbβ3, which may account for the residual fibrinogen binding detected upon platelet activation. Sequencing of genomic DNA revealed the presence of two mutations in the αIIb gene: a C1750T transition in the last codon of exon 17 changing Arg553 to STOP, and a C2829T transition in exon 27 that changes Pro912 to Leu. Sequence analysis of reversely transcribed αIIb mRNA did not detect cDNA from the C1750T mutant allele, and revealed a significant increase of the physiological splicing out of exon 28 in the cDNA carrying the C2829T mutation. Transient expression of [912Leu]αIIb in CHO-β3 cells showed a marked reduction in the rate of surface expression of αIIbβ3. Interpretation and Conclusions. The results suggest that the thrombasthenic phenotype is the result of reduced availability of αIIb-mRNA, enhanced expression of exon 28- deleted transcripts, and defective processing of [912Leu]αIIbFunding: this work was supported by a grant from the Dirección General de Investigación of the Ministerio de Educación y Ciencia (BMC2003-01409). A. Jayo is recipient of a fellowship from the Ministerio de Educación y CienciaPeer reviewe

Possible role for cellular FXIII in monocyte-derived dendritic cell motility

19 p.- 5 fig.The A subunit of plasma factor XIII (FXIII-A) is thought to function as an intracellular transglutaminase (TG) in the monocyte/macrophage lineage to regulate certain intracellular processes involving cytoskeleton remodeling, but its precise role and the functional consequences of its absence remain poorly understood. In the present study, we show that cellular FXIII (cFXIII) expression is largely upregulated during in vitro differentiation of monocytes into dendritic cells (DCs). Monodansyl-cadaverine, a competitive substrate of TG activity, inhibited basal and CCL19-stimulated migration of mature DCs. In agreement, FXIII-A-deficient DCs showed a reduced chemotactic response to CCL19. Consistent with these findings, CHO cells stably expressing human FXIII-A showed enhanced motility in transwell and scratch-wound assays. These cells displayed increased formation of membrane blebs, dynamic cell protrusions implicated in cell movement that were also observed in DCs. The results provide evidence suggesting that upregulation of cFXIII in DCs has a role in regulating cell motilityThis work was supported by grants from the Dirección General de Investigación del Ministerio de Educación y Ciencia (BFU2006-00914) and Fundación Rodríguez Pascual. A. Jayo was recipient of a fellowship from the Ministerio de Educación y Ciencia. I. Conde holds a research contract from the Consejo Superior de Investigaciones CientíficasPeer reviewe

catena-Poly[[(1,10-phenanthroline-κ(2) N,N')copper(II)]-μ-2,2'-iminodibenzoato-κ(4) O,O':O'',O''']

The structure of the title compound, [Cu(C14H9NO4)(C12H8N2)] n , consists of zigzag polymeric chains along the c axis. The asymmetric unit contains one Cu(II) atom which is coordinated by one 2,2'-imino-dibenzoate ligand and a one phenanthroline unit. Two intra-molecular N-H⋯O hydrogen bonds occur. The supra-molecular structure is characterized by weak C-H⋯O hydrogen bonds and π-π stacking inter-actions, forming a three-dimensional supramolecular network. The shortest centroid-centroid distances between neighbouring phenanthroline aromatic rings and 2,2'-imino-dibenzoate rings are 3.684 (1) and 3.640 Å, respectively. The shortest intra-chain Cu⋯Cu distance is 7.2885 (9) and the shortest Cu⋯Cu distance between Cu atoms in different chains is 7.1103 (6) Å

Naproxen co-crystals with pyridinecarboxamide isomers

A screening of naproxen cocrystals with coformers picolinamide, nicotinamide, isonicotinamide, and pyrazinamide is performed by the Kofler contact method and mechanochemistry. The solids obtained by mechanochemistry are characterized by differential scanning calorimetry, DSC, polarized light thermomicroscopy, PLTM, infrared spectroscopy, FTIR, and X-ray powder diffraction, XRPD. No cocrystal could be prepared under the experimental conditions investigated between naproxen and pyrazinamide, which bears two aromatic nitrogen atoms, ortho and meta to the amide group. For the o-, m-, and p-pyridinecarboxamide isomers, regardless of the aromatic nitrogen position, the coformer interacts with naproxen to give rise to new cocrystals: naproxen:picolinamide, naproxen2:nicotinamide, and naproxen:isonicotinamide. A supramolecular acid:aromatic nitrogen heterosynthon is found in all these cocrystals. The structure of the new naproxen:isonicotinamide compound was solved by single-crystal X-ray diffraction, SXD. As nicotinamide has FDA/GRAS status the naproxen:nicotinamide (2:1) cocrystal is of special relevance

Copper(II) complexes with 2,5-bis(2-pyridyl)pyrazine and 1,1,3,3-tetracyano-2-ethoxypropenide anion: Syntheses, crystal structures and magnetic properties

International audienceThe copper(II) complexes of formula [Cu2(2,5-dpp)(H2O)4(CF3SO3)4] · 2H2O (1) and [Cu2(2,5-dpp)(H2O)2(tcnoet)4]n (2) [2,5-dpp = 2,5-bis(2-pyridyl)pyrazine and tcnoet− = 1,1,3,3-tetracyano-2-ethoxypropenide anion] have been prepared and their structures determined by X-ray crystallographic methods. Compound 1 is a dinuclear complex where the 2,5-dpp molecule acts as a bis-bidentate bridge between the two copper centers, the electroneutrality being achieved by four terminally bound triflate anions. Each copper(II) ion presents an elongated octahedral CuN2O4 environment with two nitrogen atoms from 2,5-dpp and two water molecules in the basal plane and two triflate-oxygen atoms in the axial positions. Compound 2 is a zigzag chain of copper(II) ions with regular alternating 2,5-dpp and double tcnoet groups as bridges. Each copper(II) ion exhibits an elongated octahedral CuN5O surrounding with four nitrogen atoms, two from 2,5-dpp, one from a terminally bound tcnoet and the other from a bridging tcnoet occupying the equatorial positions and a water oxygen and a nitrogen from a monodentate tcnoet in the axial sites. The values of the copper–copper separation across 2,5-dpp are 6.763(1) (1) and 6.754(1) Å (2) whereas that through the double tcnoet bridge is 9.559(1) Å (2). The investigation of the magnetic properties of 1 and 2 in the temperature range 1.9–295 K reveal a Curie law behaviour for 1 and a very weak ferromagnetic interaction for 2. The poor ability of the 2,5-dpp ligand to mediate magnetic interactions between the copper(II) ions in the 2,5-dpp-bridged copper(II) complexes contrast with the somewhat better ability of the pyrazine ring in related pyrazine-bridged copper(II) complexes