Monoclonal antibody HK4013 recognizes an epitope specific for gastric subtype of H+,K(+)-ATPase

Monoclonal antibody HK4013 raised against hog gastric vesicles dose-dependently inhibited gastric H+,K(+)-ATPase activity, formation of phosphoenzyme from ATP, and proton uptake into gastric vesicles. This antibody did not cross-react with related P-type ATPases such as hog kidney Na+,K(+)-ATPase or rabbit sarcoplasmic reticulum Ca(2+)-ATPase. It did not bind to the solubilized gastric H+,K(+)-ATPase, indicating that this antibody recognizes a higher-order structural epitope. The epitope is present on the cytosolic surface of H+,K(+)-ATPase. The addition of K+ to a solution containing gastric H+,K(+)-ATPase decreased the fluorescence intensity of the enzyme labeled with fluorescein isothiocyanate (FITC), showing the conformational transition from the E1 to E2K+ form. When H+,K(+)-ATPase was preincubated with HK4013, the addition of K+ did not decrease but increased the FITC fluorescence, indicating that this antibody changed the conformational state, at least near the ATP binding site. This is in contrast with the case of monoclonal antibody HK4001, which inhibited the decrease of the fluorescence. The fact that these two antibodies recognize different epitopes is consistent with previously reported facts that monoclonal antibody HK4001 inhibits the ouabain-insensitive K(+)-ATPase activity of rat distal colon but antibody HK4013 does not, and that the former stains the rabbit distal H+,K(+)-ATPase but the latter does not.

Identification of a breakpoint cluster region 3' of the ribophorin I gene at 3q21 associated with the transcriptional activation of the EVI1 gene in acute myelogenous leukemias with inv(3)(q21q26)

Structural alterations occur in the long arm of chromosome 3 in approximately 2% of patients with acute myelogenous leukemia (AML) or myelodysplastic syndrome (MDS). The major alterations are inv(3)(q21q26) and t(3:3)(q21;q26) and are often classified as the 3q21q26 syndrome. We previously reported that the EVI1 gene is transcriptionally activated in AMLs with t(3;3)(q21;q26) and inv(3)(q21q26) and that the chromosomal breakpoints at 3q26 in the translocations were 5' of the EVI1 gene, whereas the breakpoints in the inversion cases were 3' of the gene. In these studies, four additional cases of AML with inv(3)(q21q26) are shown to express the EVI1 gene and to have breakpoints 3' of the gene. To characterize the 3q21 breakpoint region, cosmid and phage clones were isolated that cover approximately 100 kb. At 3q21, the breakpoints for both AMLs with t(3;3)(q21;q26) and inv(3)(q21q26) were found to cluster over a region of approximately 50 kb downstream of the Ribophorin I gene. The results indicate a common mechanism for the translocations and inversions and support the hypothesis that the transcriptional activation of the EVI1 gene is mediated by enhancer elements associated with the Ribophorin I gene.

Rifampicin prevents the aggregation and neurotoxicity of amyloid beta protein in vitro

The aggregation and cerebral deposition of amyloid beta protein (A beta), which is a major component of senile plaques in Alzheimer's disease (AD) brains, is believed to be involved in the pathogenesis of AD. Inhibition of A beta aggregation would seem to be a promising strategy for the treatment of AD. Here, we show that rifampicin, which is an antibiotic widely used in the treatment of tuberculosis and leprosy, inhibited the aggregation and fibril formation of synthetic A beta 1-40 peptide in a dose-dependent manner at reasonable concentrations. Furthermore, rifampicin was found to prevent A beta 1-40-induced neurotoxicity on rat pheochromocytoma PC12 cells. Rifampicin may have therapeutic potential as an agent for inhibiting the initial step of amyloid formation in AD.

A time course study for optimal harvest of peripheral blood progenitor cells by granulocyte colony-stimulating factor in healthy volunteers

In a search for the optimal method to harvest peripheral blood progenitor cells (PBPC) without myeloablative chemotherapy, we administered recombinant human granulocyte colony-stimulating factor (G-CSF) to adult, healthy volunteers and investigated the mobilization rate of the PBPC. The consecutive subcutaneous administration of G-CSF in a dose of 2 micrograms/kg/d for 5 days significantly increased colony-forming units-granulocyte/macrophage (CFU-GM) up to 2340 +/- 980 per mL whole blood with a 30 +/- 21-fold mobilization of PBPC, range 11- to 76-fold. Burst-forming units-erythroid (BFU-E) and mixed erythroid progenitors (CFU-Mix) were also increased, and the mobilization rate was 8.4 +/- 4.5-fold and 7.6 +/- 4.7-fold, respectively. A time course study of PBPC after final G-CSF injection was done for 0 to 30 hours on days 1, 3, and 5. After a single administration of G-CSF (day 1), there was no increment of PBPC during the subsequent 30 hours, but the white blood cell count (WBC) markedly increased. Three days after the injection of G-CSF, no increase of CFU-GM was seen during the first 2 hours, then a significant, time-dependent increase occurred for up to 30 hours. Five days after the injection of G-CSF, there was no increase of CFU-GM during the first 2 hours, and the significant increase at 24 hours was maintained for up to 30 hours. BFU-E and CFU-Mix showed the same pattern of expansion as seen with CFU-GM. Thus, subcutaneous administration of 2 micrograms/kg/d G-CSF for 5 days will lead to a successful PBPC harvest for transplantation, and the most suitable period for this is 24 to 30 hours after the final G-CSF administration.

3-Aminothymidine inhibits growth of cultured human T-cell acute lymphoblastoid leukemia cells

N3-Aminated derivatives of thymidine, deoxyuridine and deoxycytidine were synthesized and their cell growth inhibition activity was tested using two cultured human cell lines, CCRF-HSB-2 and KB. Among the compounds tested, 3-aminothymidine showed growth inhibition activity against CCRF-HSB-2 cells and inhibited DNA synthesis in these cells.

Recombinant human non-glycosylated granulocyte-macrophage colony-stimulating factor in allogeneic bone marrow transplantation: double-blind placebo-controlled phase III clinical trial

In a randomized double-blind placebo-controlled phase III clinical trial, the effects of a non-glycosylated recombinant human granulocyte-macrophage colony-stimulating factor (CSF 39-300) were investigated in patients who had received allogeneic bone marrow transplantation. CSF 39-300 was administered at a daily dose of 10 micrograms/kg (maximum dose, 300 micrograms/body) via three-hour intravenous infusions from days 1 to 21 following reinfusion of the marrow. Twenty-eight patients received CSF 39-300 and 25, placebo. The median number of days to recovery for leucocytes (> or = 1000/mm3), neutrophils (> or = 500/mm3), lymphocytes (> or = 300/mm3) and reticulocytes (> or = 20/1000) were significantly shortened (16 vs 20, 17 vs 21 and 22 vs 28, respectively) with CSF 39-300. The duration of stay in laminar-air-flow room after transplantation was also significantly shortened in the CSF 39-300 group (21 vs 30 days). There was no significant difference in the incidence of acute or chronic graft-versus-host disease between the two groups. A follow-up during the year after transplantation revealed there to be no significant difference in either survival rate or leukemia relapse rate between the two groups. CSF 39-300 is therefore considered useful after allogeneic bone marrow transplantation, especially in the early period.

Adhesion of NFS-60 myeloid leukemia cells to MC3T3-G2/PA6 stromal cells induces granulocyte colony-stimulating factor production

To examine the interaction between immature myeloid cells and stromal cells in the induction of granulocyte colony-stimulating factor (G-CSF) production, stromal cells of the MC3T3-G2/PA6 (PA6) murine cell line, which has preadipocyte characteristics and can support hematopoiesis, were cocultured with various myeloid cell lines and G-CSF mRNA expression was examined by Northern and reverse transcriptase-polymerase chain reaction analyses. A significant amount of G-CSF mRNA was induced by the culture of an interleukin-3/G-CSF-dependent murine myeloid leukemia cell line, NFS-60, on PA6 stromal cells for 16 hours. Using a G-CSF-dependent subline of DA-1 (DA-1N), the biologic activity of G-CSF was also detected in PA6/NFS-60 coculture supernatants, but not in the culture supernatant of PA6 or NFS-60 alone. Direct contact of NFS-60 cells with the PA6 stromal layer was essential for the induction of G-CSF mRNA, as indicated by the following observations: (1) NFS-60 cells efficiently adhered to PA6 cells; (2) medium conditioned by NFS-60 cells did not contain the activity to induce G-CSF mRNA in PA6 cells; and (3) induction of G-CSF mRNA was not observed when NFS-60 cells were separated from PA6 cells by a microporous membrane (0.45-microns pore size). Several other myeloid cell lines, including FDC-P2, 32Dcl3, WEHI-3, and DA-1, did not induce G-CSF mRNA expression after the coculture with PA6 cells, although significant numbers of these cells adhered to PA6 cells. Therefore, NFS-60 cells may express or overexpress a molecule that is involved in adhesion-mediated induction of G-CSF production.

Involvement of the sympathetic nervous system in antihypertensive effect of cicletanine in salt-loaded young spontaneously hypertensive rats

We examined the role of the sympathetic nervous system in the antihypertensive effect of long-term (4-week) administration of cicletanine (50 mg/100 g in diet) in young (6 week-old) spontaneously hypertensive rats (SHR) fed an 8.0% salt-containing diet. Salt loading accelerated the development of hypertension in young SHR (mean blood pressure [BP]: 158 +/- 3 v 196 +/- 5 mm Hg, P < .01). Although cicletanine did not affect mean BP in non-salt-loaded SHR, it reversed salt-induced hypertension (155 +/- 3 mm Hg, P < .01). Salt loading elevated plasma norepinephrine (NE) (246 +/- 16 v 451 +/- 87 pg/mL, P < .05) but simultaneous administration of cicletanine inhibited the increase in plasma NE with salt loading (234 +/- 12 pg/mL, P < .01). Hexamethonium, a ganglionic blocking agent, produced a greater hypotensive effect in salt-loaded than in non-salt-loaded SHR (-40 +/- 4 v -78 +/- 4 mm Hg, P < .01). In salt-loaded SHR with cicletanine, however, the hypotensive effect of hexamethonium was suppressed compared with salt-loaded SHR without cicletanine (-52 +/- 4 mm Hg, P < .01). Both plasma NE (r = 0.608, P < .01) and decrease in mean BP with hexamethonium (r = -0.798, P < .01) correlated with baseline mean BP. Thus, cicletanine inhibited the salt-induced rise in mean BP of young SHR, possibly through the suppression of enhanced sympathetic nerve activity.

Allogeneic bone marrow transplantation in Japan

Allogeneic bone marrow transplantation (BMT) is being used increasingly to treat diverse diseases in Japan. The distinctive aspects of allogeneic BMT in Japan include the lower incidence of acute graft-versus-host disease, which may be attributable to less disparity in histocompatibility antigens in Japanese. Research in the field of allogeneic BMT in Japan has covered the use of recombinant hemopoietic growth factors, especially granulocyte colony-stimulating factor, and novel immunosuppressive agents.

Regulation of recombinant human granulocyte colony-stimulation factor production using herpes simplex virus 1 thymidine kinase gene

For chronic neutropenic patients requiring long-term injection of recombinant human granulocyte colony-stimulating factor (rhG-CSF), a cellular transplantation system that can produce this cytokine stably and deliver it in a regulatory manner would be advantageous. In this study we aimed at developing a regulation system at cellular level using suicide vectors. We introduced the herpes simplex virus type 1 thymidine kinase (HSV-TK) gene into the rhG-CSF-producing NIH3T3 cells and examined if ganciclovir (GCV) treatment of the cells could control the rhG-CSF production in vitro. The cells transfected with the HSV-TK gene showed a > 100-fold increase in sensitivity to GCV compared with the parent cells, and the median inhibitory dose of GCV to the transfected cells was less than 1.6 microM. The total amount of rhG-CSF production by these cells was strongly suppressed by GCV treatment. This regulatory method may be applicable to cytokine supplement gene therapy.

An intrinsic guanine nucleotide exchange inhibitor in Gi2 alpha. Significance of G-protein self-suppression which antagonizes receptor signal

The alpha subunit of Gi2 (Gi2 alpha) is a member of the heterotrimeric G protein family, which transduces receptor signals as a proto-oncogene product. We have found a novel self-suppressive region in Gi2 alpha near its C terminus. A polypeptide consisting of residues 338-352 of Gi2 alpha (Gi2 alpha-339-352) antagonizes receptor- and receptor peptide-stimulated Gi2 alpha activation, without affecting basal activity. Antagonism by Gi2 alpha-338-352 is attributable to an interaction with activated Gi2 alpha, which is not competitive with receptor polypeptides. Combined with the reports suggesting the presence of self-suppressive domains in a juxta-C-terminal portion of Gi2 alpha and G(o) alpha, this study supports the hypothesis that Gi2 alpha-338-352 constitutes an intrinsic guanine nucleotide exchange inhibitor, which in turn antagonizes receptor stimulation, suggesting that G proteins are activated by receptors through relaxation of a self-suppressive conformation.

Richter's syndrome showing pronounced lymphadenopathy in response to administration of granulocyte colony-stimulating factor

A patient with Richter's syndrome developed rapid generalized lymph node enlargement with a decrease of peripheral blood lymphocytes after recombinant human granulocyte colony-stimulating factor (rhG-CSF) therapy for neutropenia induced by chemotherapy. The lymphadenopathy subsided spontaneously following discontinuation of rhG-CSF medication. Reinstitution of rhG-CSF therapy was followed by the same response as during initial therapy. Histopathologically, the lesions were characteristic of diffuse large cell lymphoma (DLL) with no evidence of myeloid cell involvement. No spontaneous contraction of enlarged lymph nodes followed withdrawal of the second course, but the enlargement subsided with chemotherapy. The patient died of myocardial infarction. All residual tumors examined post mortem presented microscopic features of small lymphocytic lymphoma (SLL), and G-CSF receptor was demonstrated on these neoplastic cells by Northern blot hybridization analysis. This observation indicates that some B cell malignancies may retain G-CSF receptor and respond to G-CSF.

Racemization of Asp23 residue affects the aggregation properties of Alzheimer amyloid beta protein analogues

The beta proteins in amyloid deposits of Alzheimer's disease have been found to be racemized and/or isomerized at their Asp residues (Roher, A. E., Lowenson, J. D., Clarke, S., Wolkow, C., Wang, R., Cotter, R. J., Reardon, I. M., Zurcher-Neely, H. A., Heinrikson, R. L., Ball, M. J., and Greenberg, B. D. (1993) J. Biol. Chem. 268, 3072-3083). To elucidate the effect of racemization on the aggregation properties of beta proteins, we synthesized four beta protein analogues in which D-Asp was substituted for L-Asp residues, i.e. normal beta 1-35, [D-Asp7]beta 1-35, [D-Asp23]beta 1-35, and [D-Asp7,D-Asp23]beta 1-35. The aggregation and fibril formation of the peptides were examined by means of spectrophotometry, sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS-PAGE), and electron microscopy. Of the four peptides, [D-Asp23]beta 1-35 showed the earliest increase in turbidity and appearance of a smear in SDS-PAGE. This was followed by [D-Asp7,D-Asp23]beta 1-35 and normal beta 1-35. [D-Asp7]beta 1-35 was considerably delayed in showing these signs of aggregation. Corresponding with the increase in turbidity and the appearance of a smear in SDS-PAGE, fibril formation was observed in electron microscopy. These results reveal that the aggregation properties of beta 1-35 peptides are affected by racemization of their Asp residues depending on their position. Racemization at amino acid position 23 accelerated the peptide aggregation and fibril formation, while that at position 7 slowed down this reaction. This suggests that the site-specific racemization of beta protein may be involved in the amyloid fibril formation in Alzheimer's disease.

Multiple DNA conformational changes induced by an initiator protein precede the nicking reaction in a rolling circle replication origin

The core origin for plus strand DNA replication of filamentous bacteriophage f1 binds the initiator protein (gpII), which subsequently introduces a specific nick in the plus strand. The core origin consists of a nicking region and a binding region. The binding of gpII occurs in two steps, forming a binding intermediate (complex I) and a functional complex for nicking (complex II). Results of gel retardation experiments using circularly permuted DNA fragments and direct visualization by electron microscopy show that gpII induces successive bends within the binding region upon formation of the complexes. We show that gpII binding induces duplex melting in the nicking region using KMnO4 modification of unpaired thymidine residues as a probe for melting. Origin binding occurred in the absence of superhelicity of DNA and Mg2+, whereas duplex melting required superhelical DNA, but not Mg2+. Deletion analyses indicated that hypothetical formation of a cruciform around the nicking site is not necessary for either melting or nicking. A mutation in gpII resulted in stimulation of duplex melting and nicking without showing obvious effects on bending. This suggests that the mechanism of melting involves local interaction between gpII and the nicking region. Furthermore, using synthetic oligonucleotide substrates, we show that the nicking reaction takes place efficiently when the nicking region is single-stranded and the binding region is double-stranded. These results indicate that the nicking reaction is preceded by an ordered series of protein-induced DNA-conformational changes: successive bending of the origin upon gpII binding, followed by duplex melting that requires negative superhelicity.

C-terminal topology of gastric H+,K(+)-ATPase

An antibody was prepared against a peptide corresponding to residues 1024-1034 (the putative C-terminus) of the alpha-subunit of hog gastric H+,K(+)-ATPase. The antibody bound to a 95 kDa band of H+,K(+)-ATPase that was solubilized in SDS, but not to that of Na+,K(+)-ATPase. It also bound to products of tryptic digestion that included C-terminal fragments of the H+,K(+)-ATPase alpha-subunit. The same amount of the antibody bound to both intact (tight) and lyophilized (leaky) inside-out gastric vesicles, indicating that its epitope is present on the cytosolic side of the vesicles. This finding was further confirmed by using fluorescence-immunolocalization techniques and streptolysin-O to permeabilize newt oxyntic cells. Stimulation of isolated newt oxyntic cells with dibutyryl cyclic AMP induces fusion of tubulovesicles with the apical membrane, so that the luminal domains of the H+,K(+)-ATPase alpha-subunit directly face the cell-suspension medium. The antibody did not bind to the stimulated intact cell, but bound to cells permeabilized with streptolysin-O, indicating that it binds from the cytoplasmic side to the C-terminus of the H+,K(+)-ATPase alpha-subunit in apical and tubulovesicular membrane, and also that the H+,K(+)-ATPase alpha-subunit has an even number of transmembrane domains.

Effect of long-term cyclic mechanical load on protein synthesis and morphological changes in cultured myocardial cells from neonatal rat

We studied the effect of prolonged cyclic mechanical stimulation on protein synthesis and morphological changes in cultured cardiac myocytes isolated from 3-day-old neonatal rats to develop an in vitro model for cardiac hypertrophy induced by a mechanical load. Myocardial cells were cultured on deformative culture plates with M-199 culture medium in the presence or absence of fetal calf serum (FCS), and a cyclic mechanical load was applied for 2 hours up to 15 days. Mechanical stimulation for 2 hours increased the 14C-phenylalanine incorporation rate of myocardial cells, both in the absence and presence of FCS or when the myocardial cells were either beating or arrested with tetrodotoxin. The incorporation rate always increased by mechanical stimulation during 15 days of cell culture as compared to cells that sustained no mechanical stress. The cell size and protein content, which increased gradually with mechanical stimulation and reached a maximum at 10 days, were even greater in the presence of FCS. Within 10 days myocardial cells had aligned in the direction of the maximal cyclic mechanical load. In these cells electron microscopy revealed an increase in the number of myofilaments associated with the development of mitochondria as recognized in the adult myocardial cells. These results indicate that long-term cyclic mechanical loading of cultured myocardial cells may be a good in vitro model for the study of cardiac hypertrophy.

Characterization of larvicidal toxin protein from Bacillus thuringiensis serovar japonensis strain Buibui specific for scarabaeid beetles

The delta-endo toxin proteins from Bacillus thuringiensis which kill the larvae of various scarabaeid beetles such as Anomala cuprea, A. rufocuprea and Popillia japonica were purified by DEAE ion exchange chromatography. A protein with a molecular size of 130 kDa was purified. During the purification a minor peak was also detected which was estimated to be 67 kDa by SDS-PAGE. Both 130 and 67 kDa proteins showed larvicidal activity against A. cuprea. The lethal concentration of the 130 kDa protein which killed 50% of the larvae tested (LC50) against A. cuprea was 2 micrograms g-1 compost. A comparison by SDS-PAGE of the V8 protease digestion pattern of the 130 and 67 kDa larvicidal proteins showed that proteolytic resistant core peptides of approximately 60 kDa molecular size were resulted. The N-terminus amino acid sequence of the 130 and 67 kDa proteins was determined to be NH2-XXPNNQNEYEIIDAL and NH2-XSRNPGTFI, respectively, which is not identical to the sequence of CryIA, CryIB, CryIC and CryIII proteins.

Activation of G protein-coupled K+ channels by dopamine in human GH-producing cells

Dopamine (DA) inhibited the secretion of growth hormone (GH) from cultured human GH-secreting adenoma cells. The mechanism of this DA effect on these cultured cells was investigated with electrophysiological techniques. Under current clamp, DA (10(-6) M) hyperpolarized the membrane and arrested Ca(2+)-dependent action potentials. Voltage clamp experiments revealed that this membrane hyperpolarization was the result of a K+ conductance increase caused by DA. The current-voltage relationship of the DA-induced K+ current showed an inward-going rectification. Application of sulpiride (10(-6) M) abolished the DA-induced K+ current, indicating that the hyperpolarization was caused by the activation of D2-like receptors. Pertussis toxin (PTX) treatment eliminated the DA-induced K+ current as well as the DA-induced inhibition of GH secretion. An intracellular application of guanosine-5'-O-(3-thiotriphosphate) (100 microM) evoked a spontaneous increase in the K+ current in the absence of an agonist, and the application of DA did not further increase conductance. Intracellular application of guanosine-5'-O-(2-thiodiphosphate) (2 mM) inhibited the DA-induced K+ current. These results indicate that the DA-induced K+ channel is coupled to a G protein. When adenosine 3',5'-cyclic monophosphate (cAMP, 100 microM) was added to the patch-pipette solution, the DA-induced K+ current was still observed, indicating that the DA-induced K+ current was not caused by an inhibition of cAMP production.(ABSTRACT TRUNCATED AT 250 WORDS)

Molecular cloning and characterization of G-CSF induced gene cDNA

G-CSF (granulocyte colony-stimulating factor) is known to specifically stimulate the production and the functional activation of neutrophils. To investigate the intracellular signaling pathway of myeloid cells stimulated by G-CSF, we isolated new genes whose expression was induced by G-CSF. First of all, we constructed lambda gt10 cDNA library from G-CSF-stimulated mononuclear cells (MNC) of a chronic myelogenous leukemia (CML) patient (CML-MNC) and screened the cDNA library by a differential hybridization method. The 24 candidate clones which specifically hybridized with G-CSF-stimulated CML-MNC cDNA probes, but not with unstimulated CML-MNC cDNA probes, were obtained after 8 x 10(4) individual clones had been screened. One of these clones, GIG-1 (G-CSF-induced gene-1), was further characterized. The size of the GIG-1 mRNA was about 0.9kb. The GIG-1 mRNA was expressed mainly in the myeloid leukemic cell lines.