Mutation analysis of the acid ceramidase gene in Japanese patients with Farber disease

Farber disease is a rare lysosomal storage disease, characterized by the accumulation of ceramide in tissues due to acid ceramidase deficiency. Here we report the identification of three novel mutations in the acid ceramidase gene from two Japanese patients. Patient 1 showed joint problems at around 10 months of age and the patient is now emaciated, with multiple nodules and mild neurological problems at 10 years of age. Patient 2 had consanguineous parents and showed joint contractures at around 8 months of age. He showed neurological symptoms around 2 years of age and died at 6 years owing to respiratory failure. The diagnosis was made clinically and was confirmed by enzymatic assay of acid ceramidase. Molecular analysis of cultured skin fibroblasts showed normal mRNA levels expressed in both patients. By direct sequencing of cDNA, missense mutations of V97E in exon 4 and G235R in exon 9 were detected in patient 1 and 96delV in exon 4 was homozygously identified in patient 2. These mutations were also confirmed in genomic DNA. Expression of mutated acid ceramidase cDNA in COS-1 cells showed acid ceramidase activity decreased to 35%, 2% and 37% of control value, respectively. We also found a new polymorphism V3691 in exon 14 in the allele from the mother of patient 1. To date, 13 mutations, including our newly identified mutations, have been reported. All these mutations were genetically private and genotype-phenotype correlations could not be made.

Characterization of genomic sequence coding for bromelain inhibitors in pineapple and expression of its recombinant isoform

Bromelain inhibitor (BI) is a cysteine proteinase inhibitor isolated from pineapple stem (Reddy, M. N., Keim, P. S., Heinrikson, R. L., and Kézdy, F. J. (1975) J. Biol. Chem. 250, 1741-1750). It consists of eight isoinhibitors, and each isoinhibitor has a two-chain structure. In this study, the genomic DNA has been cloned and found to encode a precursor protein with 246 amino acids (M(r) = approximately 27,500) containing three isoinhibitor domains (BI-III, -VI, and -VII) that are 93% identical to one another in amino acid sequences. The gene structure indicated that these isoinhibitors are produced by removal of the N-terminal pre-peptide (19 residues), 3 interchain peptides (each 5 residues), 2 interdomain peptides (each 19 residues), and the C-terminal pro-peptide (18 residues). Moreover, all the amino acid sequences of bromelain isoinhibitors could be explained by removal of one or two amino acids from BI-III, -VI, and -VII with exopeptidases. A recombinant single-chain BI-VI with and without the interchain peptide showed the same and no bromelain inhibitory activity as compared with the native BI-VI, respectively. These results indicate that the interchain peptide plays an important role of the folding process of the mature isoinhibitors.

Basigin expression and hormonal regulation in the rat uterus during the peri-implantation period

Basigin is essential for fertilization and implantation. The aim of this study was to determine the expression and hormonal regulation of the basigin gene in the rat uterus during the peri-implantation period. Basigin mRNA was localized strongly in the luminal epithelium on day 1 of pregnancy and gradually decreased to a basal concentration from day 3 to day 5 of pregnancy. Basigin mRNA and protein were expressed strongly in the implanting blastocyst and primary decidua on day 6 of pregnancy. A similar expression pattern was also induced in the uterus after delayed implantation was terminated by oestrogen treatment and the embryo implanted, whereas expression was not detected during delayed implantation. Basigin expression was not detected on day 6 of pseudopregnancy. Basigin mRNA was expressed strongly in the decidua on days 7 and 8 of pregnancy. Furthermore, both basigin mRNA and protein were induced in the decidua during artificial decidualization. In addition, oestrogen stimulated strong expression of basigin mRNA in the uterine epithelium of ovariectomized rats. These findings indicate that basigin may play a role during implantation and decidualization in rats.

A case of mixed membranous nephropathy and purpura nephritis

We report the case of a 71-year-old man with mixed glomerular lesions, membranous and necrotizing changes. The patient had abdominal pain and purpurat on the extremities and trunk, followed by melena, and after admission to hospital, proteinuria and occult blood were noted. Laboratory findings were negative for autoimmune disease and viral hepatitis. Renal biopsy showed segmental necrotizing changes and mesangial proliferation with spike formation. Immunofluorescence revealed a granular deposition of IgA predominantly in the mesangial area in contrast to the granular IgG deposition along the glomerular capillary loops. Moreover, electron-microscopically, mesangial as well as subepithelial electron-dense deposits were observed. These data suggest that the patient had 2 distinct types of glomerulonephritis simultaneously: idiopathic membranous nephropathy and purpura nephritis.

Behaviour of a sperm surface transmembrane glycoprotein basigin during epididymal maturation and its role in fertilization in mice

Basigin (bsg) is a transmembrane glycoprotein belonging to an immunoglobulin superfamily and is localized on the surface of the sperm tail. The behaviour of bsg during epididymal maturation and its role in fertilization were examined using an anti-bsg antibody. Spermatozoa from caput, corpus and cauda epididymides were immunostained by indirect immunofluorescence (IIF). Immunostaining revealed that bsg is localized on the principal piece of caput spermatozoa and the molecule was found on the middle piece during transit in the corpus and cauda epididymides. Concomitantly, the molecular mass of bsg was reduced from 37 kDa (testis) to 26 kDa (cauda epididymidis). IVF experiments were designed to assess the effect of anti-bsg antibody on the fertilization events. Anti-bsg antibody significantly inhibited primary binding to the cumulus-invested oocytes with intact zonae pellucidae in a dose-dependent manner. Consequently, the fertilization rate of cumulus-invested oocytes with intact zonae pellucidae was also inhibited. The bsg molecule was also detected on the head of live capacitated spermatozoa by IIF under IVF conditions. These findings indicate that testicular bsg is a glycosylated protein that undergoes molecular processing and deglycosylation during its transit in the epididymis. The bsg molecule that was detected on the sperm head after capacitation may facilitate the primary binding or might be involved in distinct events required for primary binding of spermatozoa to the zona pellucida during capacitation and sperm-cumulus interaction.

Impact of final coronary flow velocity reserve on late outcome following stent implantation

Aims To assess whether coronary flow velocity reserve following stent implantation is predictive of the subsequent need of target lesion revascularization. Methods and Results The outcome was examined of 417 patients enrolled in a multicentre prospective randomized study (DESTINI), who received a successful single vessel stent implantation in native coronary arteries and in whom coronary flow velocity reserve was measured. Logistic regression analysis and the receiver operator characteristic curve were used. When compared with 358 patients not requiring target lesion revascularization, 59 patients (14%) who underwent target lesion revascularization had a lower final coronary flow velocity reserve (2.33 +/- 0.87 vs 2.48+/- 0.80, P= 0.20) and smaller final minimal lumen diameter (2.62 +/- 0.66 mm vs 2.73+/- 0.60, P= 0.19); however, those differences were not statistically significant. Patients with a coronary flow velocity reserve of < 2.0 (n=109, 26%) exhibited a significantly higher target lesion revascularization rate than patients with a coronary flow velocity reserve of > or = 2.0 (22% vs 11%, P= 0.010). This difference remained significant (odds ratio=2.01, 95% CI=1.11 to 3.66) after adjustment for other variables that were also correlated with the incidence of target lesion revascularization. Conclusion The presence of a final coronary flow velocity reserve of < 2.0 is an independent predictor of the need for target lesion revascularization after stent implantation in native coronary artery lesions.

Disruption of the midkine gene (Mdk) resulted in altered expression of a calcium binding protein in the hippocampus of infant mice and their abnormal behaviour

BACKGROUND

Midkine (MK) is a growth factor implicated in the development and repair of various tissues, especially neural tissues. However, its in vivo function has not been clarified.

RESULTS

Knockout mice lacking the MK gene (Mdk) showed no gross abnormalities. We closely analysed postnatal brain development in Mdk(-/-) mice using calcium binding proteins as markers to distinguish neuronal subpopulations. Intense and prolonged calretinin expression was found in the dentate gyrus granule cell layer of the hippocampus of infant Mdk(-/-) mice. In infant Mdk(+/+) mice, calretinin expression in the granule cell layer was weaker, and had disappeared by 4 weeks after birth, when calretinin expression still persisted in Mdk(-/-) mice. Furthermore, 4 weeks after birth, Mdk(-/-) mice showed a deficit in their working memory, as revealed by a Y-maze test, and had an increased anxiety, as demonstrated by the elevated plus-maze test.

CONCLUSION

Midkine plays an important role in the regulation of postnatal development of the hippocampus.

The unique sites in SulA protein preferentially cleaved by ATP-dependent Lon protease from Escherichia coli

SulA protein is known to be one of the physiological substrates of Lon protease, an ATP-dependent protease from Escherichia coli. In this study, we investigated the cleavage specificity of Lon protease toward SulA protein. The enzyme was shown to cleave approximately 27 peptide bonds in the presence of ATP. Among them, six peptide bonds were cleaved preferentially in the early stage of digestion, which represented an apparently unique cleavage sites with mainly Leu and Ser residues at the P1, and P1' positions, respectively, and one or two Gln residues in positions P2-P5. They were located in the central region and partly in the C-terminal region, both of which are known to be important for the function of SulA, such as inhibition of cell growth and interaction with Lon protease, respectively. The other cleavage sites did not represent such consensus sequences, though hydrophobic or noncharged residues appeared to be relatively preferred at the P1 sites. On the other hand, the cleavage in the absence of ATP was very much slower, especially in the central region, than in the presence of ATP. The central region was predicted to be rich in alpha helix and beta sheet structures, suggesting that the enzyme required ATP for disrupting such structures prior to cleavage. Taken together, SulA is thought to contain such unique cleavage sites in its functionally and structurally important regions whose preferential cleavage accelerates the ATP-dependent degradation of the protein by Lon protease.

Syndecan-4 deficiency leads to high mortality of lipopolysaccharide-injected mice

Syndecan-4 is a transmembrane heparan sulfate proteoglycan belonging to the syndecan family. Following intraperitoneal injection of lipopolysaccharide (LPS), syndecan-4-deficient mice exhibited high mortality compared with wild-type controls. Severe endotoxin shock was observed in the deficient mice: systolic blood pressure and left ventricular fractional shortening were lower in the deficient mice than in the wild-type controls 9 h after LPS injection. Although histological examinations revealed no apparent differences between two groups, the plasma level of interleukin (IL)-1beta was higher in the deficient mice than in the wild-type controls 9 h after LPS injection. Consistent with the regulatory roles of syndecan-4, its expression in monocytes and endothelial cells of microvasculature increased in the wild-type mice after LPS administration. Although IL-1beta was produced to the same extent by macrophages from syndecan-4-deficient and wild-type mice after LPS stimulation, inhibition of its production by transforming growth factor-beta1 was impaired in the syndecan-4-deficient macrophages. These results indicate that syndecan-4 could be involved in prevention of endotoxin shock, at least partly through the inhibitory action of transforming growth factor-beta1 on IL-1beta production.

Antisense oligodeoxynucleotide targeted to Midkine, a heparin-binding growth factor, suppresses tumorigenicity of mouse rectal carcinoma cells

Midkine (MK), a heparin-binding growth factor, is overexpressed in a wide range of human carcinomas and is believed to contribute to tumorigenesis and tumor progression. To develop an antitumor reagent, we designed a phosphorothioate antisense oligodeoxynucleotide molecule based on the secondary structure of MK mRNA. The antisense MK at the dosage of 5 microM suppressed MK production by CMT-93 mouse rectal carcinoma cells after cationic liposome-mediated transfection, to 13% of that in control cultures. The growth of CMT-93 cells and their colony formation in soft agar were inhibited by the addition of the antisense MK, whereas the control reagent, the sense MK, showed no effects. On s.c. injection into nude mice, CMT-93 cells transfected with the antisense MK formed tumors much smaller than those by control cells. Finally, untreated CMT-93 cells were inoculated to nude mice, and 7 days later the antisense MK (50 microM) with atelocollagen was directly injected into the preformed tumor region to evaluate the curative effect; the injection was repeated at the interval of 2 weeks. During the period of 10-41 days after initiation of therapy, the rate of increase of tumor volume treated with the antisense MK was found to be about 4.2-fold lower than that seen after treatment with the sense MK. On this occasion, proliferation of tumor cells as estimated by 5-bromodeoxyuridine incorporation was strongly inhibited, whereas angiogenesis was less affected. These findings strongly suggested the usefulness of MK antisense oligodeoxynucleotide as a new reagent for cancer therapy.

A midkine promoter-based conditionally replicative adenovirus for treatment of pediatric solid tumors and bone marrow tumor purging

The treatment of advanced neuroblastoma (NB) or Ewing's sarcoma (ES) is one of the major challenges in pediatric oncology. Both malignancies are refractory to conventional therapies and have an extremely poor prognosis. High-dose myeloablative radiochemotherapy with autologous bone marrow or peripheral blood stem cell rescue is one of the most aggressive treatments attempted for these diseases but is often undermined by residual tumor cells contaminating the graft. Thus, in this approach, purging of tumor cells from the graft is key to the prevention of relapse after transplantation. We investigated a novel approach to eliminate tumor cells from the bone marrow or peripheral blood stem cell graft without causing stem cell damage through the use of a conditionally replicative adenovirus (Ad). ES and NB are sensitive to Ad infection, and advanced NBs express a high level of the growth/differentiation factor midkine (MK). We confirmed in this study that ES cell lines (SK-ES-1 and RD-ES) are also sensitive to Ad infection and express high levels of MK. In contrast, CD34+ stem cells are refractory to Ad infection and express very little MK. A conditionally replicative Ad in which the expression of E1 is controlled by the MK promoter achieved good levels of viral replication in NB or ES and induced remarkable tumor cell killing. On the other hand, this virus caused no damage to CD34+ cells even after 3 h of infection at a dose of 1000 multiplicity of infection. We concluded that application of this replication-competent Ad to hematopoietic grafts could be a simple but effective procedure to achieve complete tumor cell purging.

In vivo gene electroporation of glial cell line-derived neurotrophic factor (GDNF) into skeletal muscle of SOD1 mutant mice

Motor neurons degenerate with intracellular vacuolar change and eventually disappear in spinal cords of SOD1 mutant mice, resembling human amyotrophic lateral sclerosis (ALS). The GDNF gene was electroporatically transferred into the leg muscles of SOD1 mutant mice and expressed in muscle cells. This gene therapy with GDNF delayed the deterioration of motor performance, being retrogradely transported into spinal motor neurons. However, the number of the motor neurons and survival of the mutant mice were not improved by GDNF treatment. These results indicate that in vivo gene electroporation of GDNF into muscles could be an appropriate therapeutic approach to ameliorate an early dysfunction of motor neurons in SOD1 mutant mice, but further improvement is needed to use this gene transfer as an effective treatment of ALS.

Elevated gastrin secretion by in vivo gene electroporation in skeletal muscle

Whether or not in vivo gene transfer of gastrin gene into skeletal muscle by electroporation could modify gastrin secretion was examined. The expression plasmid vector, either pMEPrGaspA encoding the rat gastrin gene or pEGFP-N1 encoding the GFP reporter gene was injected into M. rectus abdominis of rats or M. biceps formis of mice. Subsequently, square electric pulses of direct current were applied six times at 25 V with a loading period of 100 msec per pulse. Clear foreign gene expression in the skeletal muscle was demonstrated by both GFP fluorescence and immunostaining of rat gastrin. Time course changes in plasma gastrin levels after transfection revealed that in rats, gastrin gene transfer significantly increased the plasma gastrin level for 4 weeks post-transfection (P<0.05), but the difference diminished at the end of the 10-week period. In mice, plasma gastrin level elevated similarly for 3 weeks, and pH of gastric contents decreased in the gastrin gene transfected group compared with the control counterpart (P<0.05). These findings suggest that localized in vivo gene transfer by electroporation allows skeletal muscle to become an artificial endocrine tissue for hormonal manipulation of animals.

In situ visualization of ultraviolet-light-induced DNA damage repair in locally irradiated human fibroblasts

We have developed a novel method that uses a microfilter mask to produce ultraviolet-induced DNA lesions in localized areas of the cell nucleus. This technique allows us to visualize localized DNA repair in situ using immunologic probes. Two major types of DNA photoproducts [cyclobutane pyrimidine dimers and (6-4) photoproducts] were indeed detected in several foci per nucleus in normal human fibroblasts. They were repaired at those localized sites at different speeds, indicating that DNA photoproducts remain in relatively fixed nuclear positions during repair. A nucleotide excision repair protein, proliferating cell nuclear antigen, was recruited to the sites of DNA damage within 30 min after ultraviolet exposure. The level of proliferating cell nuclear antigen varied with DNA repair activity and diminished within 24 h. In contrast, almost no proliferating cell nuclear antigen fluorescence was observed within 3 h in xeroderma pigmentosum fibroblasts, which could not repair either type of photolesion. These results demonstrate that this technique is useful for visualizing the normal nucleotide excision repair process in vivo. Interestingly, however, in xeroderma pigmentosum cells, proliferating cell nuclear antigen appeared at ultraviolet damage sites after a delay and persisted as late as 72 h after ultraviolet exposure. This result suggests that this technique is also valuable for examining an incomplete or stalled nucleotide excision repair process caused by the lack of a single functional nucleotide excision repair protein. Thus, the technique provides a powerful approach to understanding the temporal and spatial interactions between DNA damage and damage-binding proteins in vivo.

Midkine binds to 37-kDa laminin binding protein precursor, leading to nuclear transport of the complex

Midkine (MK) is a heparin binding multifunctional protein that promotes cell survival and cell migration. MK was found to bind to 37-kDa laminin binding protein precursor (LBP), a precursor of 67-kDa laminin receptor, with K(d) of 1.1 nM between MK and LBP-glutathione-S-transferase fusion protein. The binding was inhibited by laminin, anti-LBP, amyloid beta-peptide, and heparin; the latter two are known to bind to MK. In CMT-93 mouse rectal carcinoma cells, LBP was mostly located in the cytoplasm as revealed by immunostaining with anti-LBP antibody. That a portion of LBP or 67-kDa laminin receptor was located at the surface of these cells was verified by inhibition of cell attachment to laminin-coated dishes by anti-LBP antibody. When MK was added to culture medium of these cells, a part of LBP migrated to the nucleus. The movement occurred concomitantly with nuclear transport of biotin-labeled MK. These findings suggested that the binding of MK to LBP caused nuclear translocation of the molecular complex.

Alcoholism, ALDH2*2 allele and the A1 allele of the dopamine D2 receptor gene: an association study

The inactive form of aldehyde dehydrogenase-2 (ALDH2) is regarded as a protective factor against the development of alcoholism, and alcoholics with inactive ALDH2 are considered to be relatively homogeneous. This examination of a possible allelic association of the dopamine D2 receptor (DRD2) gene TaqI A polymorphism failed to detect significant differences between 583 Japanese alcoholics and 295 unrelated Japanese controls, or between alcoholic subjects with different ALDH2 genotypes. Despite the significantly higher frequency of the DRD2 A1 allele in the 207 alcoholics with inactive ALDH2 than in the 376 alcoholics with active ALDH2, multiple logistic regression analysis (controlled for the ALDH2 genotype) revealed no association between the TaqI A polymorphism and alcoholism. Nor did the frequency of the DRD2 TaqI A polymorphism differ in alcoholic subjects grouped by several pertinent clinical characteristics, including severity of alcoholism. Although there remains a possibility that the DRD2 TaqI A polymorphism plays some role in modifying the phenotype of the disease, these results suggest that neither the A1 allele nor the homozygous A1 genotype is associated with alcoholism.

Enhancement of diphtheria toxin-induced apoptosis in Vero cells by combination treatment with brefeldin A and okadaic acid

In the present study, we compared the abilities of ricin and diphtheria toxin to induce apoptosis in Vero cells. The cytolysis and DNA fragmentation by ricin paralleled its protein synthesis inhibitory activity. However, unlike ricin, diphtheria toxin could induce neither cytolysis nor DNA fragmentation in Vero cells up to very high concentration, in spite of the fact that Vero cells were even more sensitive to protein synthesis inhibition by diphtheria toxin than ricin. Interestingly, coexistence of brefeldin A (BFA) and okadaic acid (OA) significantly enhanced diphtheria toxin-mediated cytolysis and DNA fragmentation without affecting the activity of protein synthesis inhibition. Ammonium chloride almost completely abolished the ability of diphtheria toxin to induce apoptosis in the presence of BFA and OA as well as the protein synthesis inhibitory activity. The mutant CRM 197, which does not catalyze the ADP ribosylation of elongation factor-2 (EF-2), failed to induce apoptosis in Vero cells even in the presence of BFA and OA. Thus, translocation of diphtheria toxin into the cytosol and subsequent enzymatic inactivation of EF-2 may be necessary steps to induce apoptosis. Taken together our results suggest that protein synthesis inhibition by toxins is not sufficient to induce apoptosis, and underlying mechanisms of apoptosis induction may be distinct between ricin and diphtheria toxin. Since a morphological change in the Golgi complex was observed in Vero cells treated with BFA and OA, modulation of the Golgi complex by these reagents may be partly responsible for enhanced apoptosis induction by diphtheria toxin.

Expression of midkine in the cochlea

Midkine (MK) is one of a new family of heparin-binding growth factors involved in the regulation of growth and differentiation. We have analyzed expression of MK in the cochlea using ICR mice within 1 day from birth. The expression of MK in the cochlea was confirmed by Western blotting and immunohistochemistry. Anti-MK immunoreactivity was observed in the stria vascularis, spiral prominence, spiral ganglion, and ganglion nerve fibers. These findings suggest that MK plays a role in the development of the cochlea.

Functional analysis of promoter activity of murine beta-1,6-N-acetylglucosaminyltransferase

In the mouse, beta-1,6-N-acetylglucosaminyltransferase (IGnT) forms branches in poly-N-acetyllactosamines, which are good scaffolds for oncodevelopmental cell-surface antigens and recognition markers. There are two isoforms of IGnT, IGnT A and B, which are produced by alternative splicing of the IGnT gene; the unique portion is encoded by exon 1 and common portion is encoded by exons 2 and 3. Thus, the expression of each isoform is controlled by a different promoter. Here, we identified the regulatory regions of the mouse IGnT A and B genes. The promoter regions for IGnT A and B did not contain putative TATA or CAAT boxes, but each contained GT boxes. The upstream regulatory region of each gene was examined by transient luciferase reporter gene transfection experiments and gel mobility shift assay. Promoter activity for each gene was detected in F9 embryonal carcinoma cells, which express IGnT A and B, but not in N2a cells, which do not express the gene. Deletion analysis demonstrated that the regions 308 bp upstream from the transcriptional initiation site of IGnT A and 430 bp upstream from the transcriptional initiation site of IGnT B showed minimal promoter activity. Mutation of the single GT box in IGnT A and two GT boxes in IGnT B caused marked reduction of the promoter activity. These findings provided strong evidence that the GT boxes play crucial roles in transcriptional regulation of the genes.

Midkine is involved in neutrophil infiltration into the tubulointerstitium in ischemic renal injury

Midkine (MK) is a multifunctional heparin-binding protein and promotes migration of neutrophils, macrophages, and neurons. In the normal mouse kidney, MK is expressed in the proximal tubules. After renal ischemic reperfusion injury, its expression in proximal tubules was increased. Immediate increase of MK expression was found when renal proximal tubular epithelial cells in culture were exposed to 5 mM H(2)O(2). Histologically defined tubulointerstitial damage was less severe in MK-deficient (Mdk(-/-)) than in wild-type (Mdk(+/+)) mice at 2 and 7 days after ischemic reperfusion injury. Within 2 days after ischemic injury, inflammatory leukocytes, of which neutrophils were the major population, were recruited to the tubulointerstitium. The numbers of infiltrating neutrophils and also macrophages were lower in Mdk(-/-) than in Mdk(+/+) mice. Induction of macrophage inflammatory protein-2 and macrophage chemotactic protein-1, chemokines for neutrophils and macrophages, respectively, were also suppressed in Mdk(-/-) mice. Furthermore, renal tubular epithelial cells in culture expressed macrophage inflammatory protein-2 in response to exogenous MK administration. These results suggested that MK enhances migration of inflammatory cells upon ischemic injury of the kidney directly and also through induction of chemokines, and contributes to the augmentation of ischemic tissue damage.

Unidimensional scale for dementia

A cognitive test comprising 27 subscales was administered to 262 demented patients and 92 normal subjects. Principal factor analysis followed by varimax and Harris-Kaiser rotation and Guttman's scalogram analysis was performed. The analysis yielded three factors, i.e. "recent memory", "immediate memory or attention" and "remote memory". The relationships between the three-dimensional distribution of the scores and the DSM-IIIR grade of dementia indicated the existence of a continuum of dementia severity. Scalogram analysis showed unidimensionality in the difficulty level of the subscales as well as in the severity of the cases. Thus, the simple summary score can be used as a good measure of the severity of dementia.