Purification and characterization of an abnormal factor IX (Christmas factor) molecule. Factor IX Chapel Hill

Human Factor IX (Christmas factor) was isolated from the plasma of a patient with mild hemophilia B. The patient's plasma contained 5% Factor IX clotting activity but 100% Factor IX antigenic activity as determined by immunological assays, which included inhibitor neutralization and a radioimmunoassay for Factor IX. This abnormal Factor IX is called Factor IX Chapel Hill (Factor IXCH). Both normal Factor IX and Factor IXCH have tyrosine as the NH2-terminal amino acid. The two proteins have a similar molecular weight, a similar amino acid analysis, the same number of gamma-carboxyglutamic acid residues (10 gamma-carboxyglutamic acid residues), and a similar carbohydrate content. Both exist as a single-chain glycoprotein in plasma. The major difference between normal Factor IX and Factor IXCH is that the latter exhibits delayed activation to Factor IXa in the presence of Factor XIa and Ca2+. Thus, Factor IXCH differs from other previously described abnormal Factor IX molecules.     

Regulatory mechanism of human factor IX gene: protein binding at the Leyden-specific region

Hemophilia B-Leyden is characterized by the gradual amelioration of bleeding after the onset of puberty. All Leyden phenotype mutations found to date lie within the Leyden-specific region, which spans roughly nt-40 to +20 in the 5' end of the human factor IX gene. With HepG2 cell nuclear extracts, the Leyden-specific region and its immediate neighboring region of the normal factor IX gene showed five DNase I footprints: FP-I (nt +4 to +19), FP-II (nt -16 to -3), FP-III (nt -27 to -19), FP-IV (nt -67 to -49), and FP-V (nt -99 to -77). Protein binding affinities of short oligonucleotides containing sequences of FP-I, FP-II, or FP-III were substantially reduced in the presence of Leyden phenotype mutations in these areas, correlating well with the negative effects of these mutations on factor IX gene expression. A Leyden phenotype mutation at nt -20 (T to A) caused a loss of both footprints FP-III and FP-II but generated a new footprint, FP-III' (nt -34 to -23), partially overlapping with FP-III, indicating mutation-dependent competitive protein binding at these sites. Although the FP-III' area contains an androgen responsive element-like sequence, the nuclear protein that binds at FP-III' is not androgen receptor. The protein was not recognized by anti-androgen receptor antibody and, furthermore, was present not only in liver but also in both androgen receptor-positive and androgen receptor-negative cells in electrophoretic mobility shift assays. The nuclear concentration of this protein increased significantly upon treatment of the HepG2 cells with testosterone. Its binding affinity to an oligonucleotide (-32sub) containing the FP-III' sequence was greatly reduced in the presence of exogenous androgen receptor, suggesting a possible interaction of this protein with androgen receptor. The affinities of both this protein and a protein which binds to FP-III (presumably HNF-4) to -32sub with a mutation at nt -26 were grossly lowered. These findings suggest that the amelioration of hemophilia B-Leyden with a mutation at nt -20 after puberty involves binding of a specific non-androgen receptor nuclear protein at FP-III' and it is able to substitute for the function of a protein bound at FP-III in the normal gene optimally through its elevated interaction with androgen receptor upon a surge of testosterone.(ABSTRACT TRUNCATED AT 400 WORDS)     

Purification of human factor IX by chromatography of a coagulation factor concentrate

A purification procedure for, and some properties of, coagulation factor IX are described. The coagulation factor concentrate used for the treatment of hemophilia B patients was employed as the starting material. The isolation procedure consists of chromatography in DEAE-cellulose, two chromatographies in hydroxyapatite gel and two gel filtrations in Sephadex G-200. Only trace amounts of factors II, VII and X were present in the final preparation and the specific activity of factor IX was 159 corresponding 10,300 times purification from plasma. The molecular weight was estimated to be 76,000 in gel filtration and 86,000 in sodium dodecyl sulfate disc gel electrophoresis. Three activity peaks with pIs 4.15, 4.25 and 4.40 were obtained by isoelectric focusing.     

Effects of LDL-apheresis on serum lipoprotein (a), C4b binding protein, protein C, protein S, and complement components

The leakage of proteins in the immature neonatal lung can reduce the effect of exogenous surfactant. The effect of ethamsylate, a more specific prostaglandin inhibitor than indomethacin and aspirin-like drugs, on alveolar albumin leak was studied in a group of 27 immature newborn rabbits (gestational age 27 days). A pilot study was carried out using 4 animals and low-dose ethamsylate (10 mg/kg). A second group of animals (n = 12) received at birth, by intravenous injection, ethamsylate (50 mg/kg) and 10% human albumin (7 ml/kg). Animals not receiving ethamsylate (n = 11) served as control group. After 30 min of artificial ventilation with standard tidal volume (10 ml/kg) the lungs were lavaged and the amount of human albumin in lung lavage fluid was determined by immunodiffusion. No statistically significant differences were found in lung-thorax compliance and vascular to alveolar albumin leak between ethamsylate-treated animals and controls (p > 0.5). However, there was a statistically significant negative correlation between protein leak and lung compliance (r = -0.41; p < 0.04). These results suggest no direct influence of early ethamsylate administration on neonatal lung permeability in the immature neonate confirming that lung permeability is inversely related to compliance.     

Recombinant human factor IX: replacement therapy, prophylaxis, and pharmacokinetics in canine hemophilia B

Recombinant human factor IX (rFIX) has been expressed in transduced cultured cell systems since 1985. Because there has been limited in vivo testing of rFIX in hemophilia B subjects, this study was undertaken using the severe hemophilia B canines of the Chapel Hill strain. Three groups of hemophilic dogs received either 50, 100, or 200 IU/kg of rFIX. As a control, a fourth group of hemophilic dogs received 50 IU/kg of a high purity, plasma-derived human FIX (pdFIX). The coagulant and hemostatic effects of rFIX and pdFIX were similar with all comparative dosing regimens. Based on activity data, the elimination half-life of rFIX was 18.9 +/- 2.3 hours and pdFIX was 17.9 +/- 2.1 hours. A prophylactic regimen administering rFIX daily resulted in a continuous therapeutic level of plasma FIX and was accompanied by a two-fold increase in recovery levels by day 5, compared to that observed with administration of a single bolus. The mechanisms of the high to complete recovery of FIX with the prophylactic regimen could depend not only on the degree of saturation of the vascular endothelial binding sites but also on the altered dynamics of the balance of FIX distribution between the intravascular and extravascular compartments. The pharmacokinetic (PK) parameters for rFIX and pdFIX were similar. However, the relative PK values for V1 and V5s of both products on day 5 differed greatly from day 1 and may reflect the changing equilibrium of FIX between compartments with elevated levels of plasma FIX. Neutralizing antihuman FIX antibodies resulting from human FIX antigen being administered to FIX deficient dogs were observed beginning at 14 days. The antigenicity of rFIX and pdFIX appeared to be comparable. Despite the very different procedures used for production of rFIX and pdFIX products, in vivo testing in hemophilia B dogs showed the functional behavior of these products is similar; they are highly effective for replacement therapy and for prophylaxis.     

Identification of gamma-carboxyglutamic acid residues in bovine factors IX and X, and in a new vitamin K-dependent protein

A spectrophotometric assay was developed for measuring the uptake of the antibiotic actinobolin by hydroxylapatite (HAP) or powdered human enamel. The assay is sufficiently sensitive to detect less than 2.0 mug actinobolin/ml of: 0.01 M sodium phosphate buffer at pH 5.5, 7.0, or 8.0; deionized water; deionized water containing 1% salivary supernatant; or each of the above indicated solvent systems containing 1-5 parts per million sodium fluoride. The utility of the assay system has been demonstrated by date which show that approximately 5-7 mug of actinobolin are bound per 10 mg of HAP or powdered enamel.     

A novel resin glycoside, merremin (tuguajalapin X dimer), from Merremia hungaiensis

A novel resin glycoside, merremin (1), has been isolated from the root of Merremia hungaiensis (Convolvulaceae). The structure has been determined to be an ester-type dimer of tuguajalapin X (2) on the basis of chemical and spectral data.     

Regulation of organelle movement in melanophores by protein kinase A (PKA), protein kinase C (PKC), and protein phosphatase 2A (PP2A)

We used melanophores, cells specialized for regulated organelle transport, to study signaling pathways involved in the regulation of transport. We transfected immortalized Xenopus melanophores with plasmids encoding epitope-tagged inhibitors of protein phosphatases and protein kinases or control plasmids encoding inactive analogues of these inhibitors. Expression of a recombinant inhibitor of protein kinase A (PKA) results in spontaneous pigment aggregation. alpha-Melanocyte-stimulating hormone (MSH), a stimulus which increases intracellular cAMP, cannot disperse pigment in these cells. However, melanosomes in these cells can be partially dispersed by PMA, an activator of protein kinase C (PKC). When a recombinant inhibitor of PKC is expressed in melanophores, PMA-induced pigment dispersion is inhibited, but not dispersion induced by MSH. We conclude that PKA and PKC activate two different pathways for melanosome dispersion. When melanophores express the small t antigen of SV-40 virus, a specific inhibitor of protein phosphatase 2A (PP2A), aggregation is completely prevented. Conversely, overexpression of PP2A inhibits pigment dispersion by MSH. Inhibitors of protein phosphatase 1 and protein phosphatase 2B (PP2B) do not affect pigment movement. Therefore, melanosome aggregation is mediated by PP2A.     

P-glycoprotein (PGP), and not lung resistance-related protein (LRP), is a negative prognostic factor in secondary leukemias

A novel human cell line, TOM-2, was established from a rare uterine cervical cancer, glassy cell carcinoma (GCC). TOM-2 is the second established GCC cell line so far reported. The cells were intermediately or poorly differentiated with dysplastic nuclei and polygonal shape and secreted two tumor markers and cytokines, i.e., CA-125 and SCC, interleukin (1L)-1alpha, -6, and -8, and TNF-alpha. Growth of TOM-2 was so strongly dependent on population density that it was not possible to determine the plating efficiency. In mass culture, the following characteristics were observed: doubling time, 83 h; mode of chromosome number, 79; human papillomavirus type 18 DNA, detectable; tumorigenicity, easily transplantable into subcutis of nude mice; chemosensitivity in vitro, considerably sensitive to Cisplatin and 5-FU but not to 9 other antineoplastic agents. This novel cell line will be useful for developing new therapeutic strategies for the rare cancer, GCC.     

A cross-over pharmacokinetic study of a double viral inactivated factor IX concentrate (15 nm filtration and SD) compared to a SD factor IX concentrate

A double blind randomized cross-over multi-center study has been conducted to compare the pharmacokinetic and coagulation activation markers of high-purity factor IX concentrate subjected to both solvent/ detergent (SD) treatment and 15 nm-filtration (FIX-SD-15) with the licensed product subjected only to solvent-detergent (FIX-SD). This filtration process allows the elimination of small particles, such as non-enveloped viruses (i.e., hepatitis A and parvovirus B19). Eleven severe hemophilia B patients (FIX coagulant activity <2 IU/dl) received one infusion of 60 IU/kg of FIX-SD and one infusion of 60 IU/kg of FIX-SD-15 at least at 10 days interval. Blood samples were obtained before and at various time up to 72 h after infusion. The decay curves of factor IX (FIX:C and FIX:Ag) were evaluated by a model independent method. Bioequivalence was found between the two concentrates using the Schuirmann test. The mean FIX:C and FIX:Ag recovery of FIX-SD-15 was 1.08 and 0.89 IU/dl/IU/kg respectively with a mean half-life of 33.3 h for FIX:C and 25.6 h for FIX:Ag. Six months after initial enrollment, pharmacokinetic parameters were similar in the 7 patients tested. There was no significant variation of prothrombin fragment 1+2 and thrombin-antithrombin complexes measured up to 6 h after infusion, indicating that there was no activation process after administration of FIX. In conclusion, these data demonstrate that the introduction of a 15 nm filtration does not alter the pharmacokinetic profile of a well characterized SD FIX concentrate while providing additional viral safety.     

A monocyte chemotactic factor, S19 ribosomal protein dimer, in phagocytic clearance of apoptotic cells

HL-60 cells derived from a human promyelocytic leukemia underwent apoptosis by heat treatment. When the heat-treated HL-60 cells were injected into guinea pig skin, monocyte/macrophage infiltration was observed 24 or 36 hours later, and the apoptotic cells were phagocytically cleared by 48 hours after their injection. The infiltration and clearance patterns were quite different from those observed in injection of necrotic or boil-fixed HL-60 cells. The apoptotic cells released a monocyte chemotactic factor in vitro 24 hours after the heat treatment. The chemotactic factor generated was identified as the cross-linked homodimer of S19 ribosomal protein by its immunologic and physicochemical properties. A serine protease that inactivates the monocyte chemotactic factor was also released from the apoptotic cells 30 hours after the heat treatment. A super infusion of this protease into the skin where the apoptotic cells had been injected diminished the number of infiltrated monocytes. The present results indicate an important role of the S19 ribosomal protein dimer in the phagocytic clearance of apoptotic cells.     

Call for post-licensing human pharmacokinetic studies of administration of recombinant factor IX

Freeze-dried flowers of the Akinowasuregusa (Hemerocallis fulva L. var. sempervirona M. Hotta), a Hemerocallis genus of the lily family, were fed to C57BL strain mice. The slow wave sleep and paradoxical sleep of the Hemerocallis-treated group increased during the dark period. The differences between the control group and the Hemerocallis-treated group were significant (P < 0.05). The Hemerocallis feeding did not cause a change in sleep time during the light period. As a result, there was no significant change in the sleep-time percentage over a 24-h period.     

Long-term expression of human clotting factor IX from retrovirally transduced primary human keratinocytes in vivo

A persistent obstacle that has hampered gene transfer experiments is the short-term nature of transgene expression in vivo. In this article we present evidence for sustained expression from primary human keratinocytes, using the retroviral vector MFG. Primary keratinocytes were transduced in culture with the MFG retroviral vector containing the coding region from factor IX cDNA. Transduced keratinocytes, which secreted on average 830 ng of factor IX/10(6) cells/24 hr in tissue culture, were used to form a bilayered skin equivalent and grafted onto nude mice under a silicone transplantation chamber. Between 0.1 and 2.75 ng of human factor IX per milliliter was found in mouse plasma for more than 1 year, suggesting that keratinocyte stem cells were both transduced and grafted. The results show, for the first time, that long-term expression is obtainable in retrovirally transduced keratinocytes after transplantation.     

Functional consequences of the Ser334-->Pro mutation in a human factor X variant (factor XMarseille)

Phosphorylase b kinase from rabbit skeletal muscle can be phosphorylated and activated by a cyclic nucleotide- and Ca2(+)-independent protein kinase previously identified as an autophosphorylation-dependent multifunctional protein kinase (auto-kinase) from brain and liver (Yang et al., J. Biol. Chem. 262, 7034-7040 (1987) and Yang et al. J. Biol. Chem. 262, 9421-9427 (1987)). This independent kinase phosphorylates both alpha and beta subunits of phosphorylase b kinase and results in a approximately 5-fold activation of the kinase when 0.55 and 0.5 mol of phosphate are incorporated into the alpha and beta subunits, respectively. Activation of phosphorylase b kinase catalyzed by auto-kinase is about 70% of that observed with cAMP-dependent protein kinase. Analysis of phosphopeptide maps of alpha and beta subunits further reveals that both kinases phosphorylate almost the same sites on both alpha and beta subunits, suggesting that activation of phosphorylase b kinase by the two kinases may be through a common molecular action mechanism. Taken together with the previous result that auto-kinase can inactivate glycogen synthase, the present study provides initial evidence that a coordinate control mechanism for simultaneous regulation of glycogenolysis and glycogenesis can be modulated by autophosphorylation-dependent protein kinase in a cAMP- and Ca2(+)-independent pathway, representing a new mode of control mechanism for the regulation of glycogen metabolism in cells.     

Effect of granulocyte proteases on human coagulation factors IX and X. The protective effect of calcium

The inactivation of the zymogen and active forms of Factors IX and X by the effect of granulocyte proteases was investigated. As deduced from the apparent first-order inactivation rate constants, Factors IXa and Xa were about ten times as sensitive to proteolytic inactivation as the zymogen factors. In the presence of 2.5mM CaCl2 the rate of inactivation of zymogens decreased to one half. With the active factors, calcium caused complete resistance to proteolysis, prevailing for 15 min. The analysis of resistance to proteolysis, prevailing for 15 min. The analysis of resistance to proteolysis led us to the conclusion that the observed phenomenon was related to the calcium binding ability of the factors studied and can probably be explained by the protection of the active sites of enzymes.     

Neutrophil elastase cleavage of human factor IX generates an activated factor IX-like product devoid of coagulant function

In preliminary studies, the generation of thrombin in vivo was found to induce a 92% loss of functional activity of factor IX (F.IX) despite the detection by Western blotting of a product resembling activated F.IX (F.IXa) and a 25% increase in F.IX antigen levels (Hoogendoorn et al, Thromb Haemost 69:1127, 1993 [abstr]). These changes were associated with evidence of increased elastase availability. To study the possibility that these two observations were related, a detailed physical and functional characterization of the hydrolysis of purified human F.IX by human neutrophil elastase (HNE) was performed in vitro. An activated partial thromboplastin time (aPTT) clotting assay demonstrated that, although HNE eliminated the potential of F.IX to be activated, it only marginally reduced the F.IXa activity. Reducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) indicated that HNE treatment of F.IX generated cleavage products of 30 and 20 kD that could not be distinguished from the respective heavy and light chain peptides that were identified in parallel studies when F.IX was activated by activated bovine F.XI (F.XIa), one of its physiological activators. In addition, nonreducing SDS-PAGE demonstrated that HNE-treated F.IX formed no complexes with antithrombin III (ATIII) in the presence of heparin. Furthermore, HNE-treated F.IX was unable to (1) bind the active site probe p-aminobenzamidine; (2) hydrolyze the synthetic peptide substrate CH3SO2-Leu-Gly-Arg-p-nitroanilide; and (3) activate human factor X (F.X). In contrast to dansyl-Glu-Gly-Arg-chloromethyl ketone (dEGR)-inactivated F.IXa, HNE-treated F.IX (0.01 to 10,000 pmol/L) failed to inhibit the clotting activity of F.IXa (10 pmol/L) in the aPTT. NH2-terminal sequencing indicated that HNE cleaved human F.IX at Thr140, Thr144, Ile164, Thr172, and Val181. The cleavages at Thr140/Thr144 and at Thr172/Val181 are both very close to the normal F.XIa alpha-(Arg145) and beta-(Arg180) cleavage sites, respectively. In summary, the results suggest that the activatability of F.IX is eliminated after cleavage by HNE and that the inability of HNE-treated F.IX to support F.IXa-like coagulant function is a consequence of improper active site formation. These in vitro observations support the possibility that increased HNE cleavage of F.IX in vivo may contribute to the disregulation of hemostasis that occurs in conditions such as disseminated intravascular coagulation (DIC).