Characterization of NAADP-mediated calcium signaling in human spermatozoa

Ca(2+) signaling in spermatozoa plays a crucial role during processes such as capacitation and release of the acrosome, but the underlying molecular mechanisms still remain unclear. Nicotinic acid adenine dinucleotide phosphate (NAADP) is a potent Ca(2+)-releasing second messenger in a variety of cellular processes. The presence of a NAADP synthesizing enzyme in sea urchin sperm has been previously reported, suggesting a possible role of NAADP in sperm Ca(2+) signaling. In this work we used in vitro enzyme assays to show the presence of a novel NAADP synthesizing enzyme in human sperm, and to characterize its sensitivity to Ca(2+) and pH. Ca(2+) fluorescence imaging studies demonstrated that the permeable form of NAADP (NAADP-AM) induces intracellular [Ca(2+)] increases in human sperm even in the absence of extracellular Ca(2+). Using LysoTracker, a fluorescent probe that selectively accumulates in acidic compartments, we identified two such stores in human sperm cells. Their acidic nature was further confirmed by the reduction in staining intensity observed upon inhibition of the endo-lysosomal proton pump with Bafilomycin, or after lysosomal bursting with glycyl-l-phenylalanine-2-naphthylamide. The selective fluorescent NAADP analog, Ned-19, stained the same subcellular regions as LysoTracker, suggesting that these stores are the targets of NAADP action.

Ion channels in sperm motility and capacitation

Spermatozoa depend upon ion channels to rapidly exchange information with the outside world and to fertilise the egg. These efficient ion transporters participate in many of the most important sperm processes, such as motility and capacitation. It is well known that sperm swimming is regulated by [Ca2+]i. In the sea urchin sperm speract, a decapeptide isolated from egg outer envelope, induces changes in intracellular Ca2+ ([Ca2+]i), Na+, cAMP and cGMP, membrane potential (Em) and pH (pHi). Photoactivation of a speract analogue induces Ca2+ fluctuations that generate turns that are followed by straighter swimming paths. A fast component of the [Ca2+], increase that most likely occurs through voltage dependent Ca2+ channels (Ca(v)s) is essential for these turns. The Ca(v)s involved are modulated by the Em changes triggered by speract. On the other hand, mammalian sperm gain the ability to fertilise the egg after undergoing a series of physiological changes in the female tract. This maturational process, known as capacitation, encompasses increases in [Ca2+]i and pHi, as well as an Em hyperpolarization in mouse sperm. Our electrophysiological, immunological and molecular-biological experiments indicate that inwardly rectifying K+ channels regulated by ATP (KATP channels) and epithelial Na+ channels (ENaCs) are functionally present in mouse spermatogenic cells and sperm. Notably, pharmacological experiments indicate that the opening of KATP channels and closure of ENaCs may contribute to the hyperpolarization that accompanies mouse sperm capacitation. Remarkably, both in the sea urchin sperm speract response and in the mouse sperm capacitation, Em hyperpolarization seems necessary to remove inactivation from Ca(v) channels so they can then open.

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.

Ion transport in sperm signaling

Ion channels and transporters, key elements in sperm-egg signaling and environmental sensing, are essential for fertilization. External cues and components from the outer envelopes of the egg influence sperm ion permeability and behavior. Combining in vivo measurements of membrane potential, intracellular ions, and second messengers with new molecular approaches and reconstitution strategies are revealing how sperm ion channels participate in motility, sperm maturation, and the acrosome reaction. Sperm are tiny differentiated terminal cells unable to synthesize proteins and difficult to characterize electrophysiologically. Spermatogenic cells, the progenitors of sperm, have become useful tools for probing sperm ion channels since they are larger and molecular biology techniques can be applied. These complementary strategies are opening new avenues to determine how sperm ion channels function in gamete signaling.

Time-resolved sperm responses to an egg peptide measured by stopped-flow fluorometry

Speract, a decapeptide from sea urchin egg jelly, induces various sperm responses. Stopped-flow fluorometry was used to examine the binding of labeled speract and the intracellular changes in pH (pH(i)) and Ca2+ ([Ca2+]i) it induces in sperm. We observed significant time delays for the increase in pH(i) and [Ca2+]i induced by 200 nM speract (69 and 190 ms, respectively). Also, we found that the receptor undergoes a pH(i)-dependent affinity change at around 129 ms. These time delays probably reflect biochemical processes underlying each sperm response to speract that circumscribe the time sequence of the signaling events.

SSCP analysis by RT-PCR for the prenatal diagnosis of Niemann-Pick disease type C

The molecular prenatal diagnosis of Niemann-Pick disease type C (NPC) is presented. The proband with a late infantile type of NPC was a compound heterozygote of a paternal missense mutation, T529G, and a maternal 2 bp deletion at nt 350 of the NPC1 gene. These mutations were detected by single-strand conformation polymorphism (SSCP) analysis of RT-PCR products. When the proband was aged 4 years 3 months, prenatal diagnosis for the second child was performed using both biochemical and molecular methods. SSCP analysis for the parental mutations using cDNA from cultured amniotic fluid cells revealed the absence of both mutations and the fetus was diagnosed as being unaffected. This diagnosis was supported by a normal level of cholesterol esterification using cultured amniotic fluid cells. After the child's birth, when he was 21 months old, the diagnosis was confirmed by SSCP analysis of genomic DNAs of his family. This analysis also revealed a unique variation of intron 13, IVS13+753-758 del TTTTTT, that was shared only by the proband and the father, and was suspected as being linked to the T529G missense mutation. A combination of both biochemical and molecular analyses is very useful and reliable for prenatal diagnosis of Niemann-Pick disease type C.

Investigation into the mode of action of R-91650, an arylpiperazinyl fluoroquinolone, on feline immunodeficiency virus replication inhibitory activity

The mode of action of R-91650, an arylpiperazinyl fluoroquinolone, on feline immunodeficiency virus (FIV) replication inhibitory activity was investigated. R-91650 inhibited replication of FIV at non-cytotoxic concentration levels in both acutely infected peripheral blood mononuclear cells and chronically infected P-CrFK cells. The compound reduced the intracellular p24 concentration levels in P-CrFK cells in a dose-dependent manner. Northern blot analysis revealed that R-91650 selectively prevented the accumulation of FIV mRNA in P-CrFK cells. However, the compound did not inhibit FIV-long terminal repeat (LTR) promoter activity in the reporter gene expression analysis. These data suggest that R-91650 is a novel inhibitor of FIV replication that inhibits a certain step or steps following transcription initiation of the FIV-LTR promoter.

Real-time measurements of the interactions between fluorescent speract and its sperm receptor

Lytechinus pictus sea urchin sperm express receptors for speract, a sperm-activating peptide derived from the homologous egg jelly coat. We found that the fluorescence of fluorophore-labeled, active, speract analogs is quenched upon receptor binding. This property allowed us to perform real-time measurements of speract-receptor interactions using intact sperm and to determine, for the first time, their association (k(on)) and dissociation (k(off)) rate constants. The high k(on) (2.4 x 10(7) M(-1 )s(-1)) and low k(off) (4.4 x 10(-6) s(-1) (95%) and 3.7 x 10(-4) s(-1) (5%)) can account for the sperm response to picomolar concentrations of speract. We also examined the influence of extracellular ions on speract-receptor interactions using the fluorescence quenching method described in this study. The association rate of speract to the receptor is dramatically reduced in Na(+)-free seawater (NaFSW), divalent cation-free seawater (DCFSW), and high-K(+) seawater (HKSW). In seawater speract induces an increase in intracellular pH (pHi), while it is unable to do so in either NaFSW or HKSW. To test if the lack of this pHi change causes the reduction in the speract association rate, pHi was increased with NH(4)Cl (10 mM) at the time labeled speract was added. Interestingly, this procedure completely (in HKSW) or partially (in NaFSW and DCFSW) restored the speract association rate to its receptor. These findings indicate that an increase in sperm pHi positively affects the receptor binding activity for this peptide and may partially explain the positive binding cooperativity displayed by the speract receptor.

8-Difluoromethoxy-4-quinolone derivatives as anti-feline immunodeficiency virus (FIV) agents: important structural features for inhibitory activity of FIV replication

The inhibitory activities of various 8-difluoromethoxy-4-quinolone derivatives against feline immunodeficiency virus (FIV) replication in the chronically infected cell line P-CrFK were investigated. Certain derivatives were found to inhibit FIV production from P-CrFK cells in a dose-dependent manner without exhibiting cytotoxic effects at inhibitory concentrations. Based on this study, the structures important for anti-FIV activity are suggested to be (i) a carboxyl group at position C-3, and (ii) an aromatic modification at position 4 of the C-7 piperazinyl moiety.

Mutation analysis of two Japanese patients with Fanconi-Bickel syndrome

Fanconi-Bickel syndrome (FBS), or glycogen storage disease type XI, is a rare autosomal recessive disorder characterized by hepatorenal glycogen accumulation, Fanconi nephropathy, and impaired utilization of glucose and galactose. Recently, this disease was elucidated to link mutations in the glucose transporter 2 (GLUT2) gene. Only three mutations in three FBS families have been reported. Therefore, it is important to elucidate mutations in the GLUT2 gene in FBS by answering the question of whether the syndrome is a single gene disease. In this report, we describe two patients in two unrelated families clinically diagnosed with FBS. No mutation in the entire protein coding region of the GLUT2 gene was detected in patient 1, which suggested that no mutation existed in the GLUT2 gene, or that some mutations had affected the expression of the GLUT2 gene. In patient 2, a novel homozygous nonsense mutation (W420X, Trp at codon 420 to stop codon) was detected. These results support the correlation between GLUT2 gene mutation and FBS syndrome. However, many patients must be analyzed to determine whether other genes are involved in FBS.

Glycogen storage disease type Ia: molecular diagnosis of 51 Japanese patients and characterization of splicing mutations by analysis of ectopically transcribed mRNA from lymphoblastoid cells

Glycogen storage disease type Ia (GSD-Ia) is an autosomal recessive disorder of glycogen metabolism caused by a deficiency of glucose-6-phosphatase (G6Pase) that is expressed in the liver, kidney, and intestinal mucosa. Clinical manifestations include short stature, hepatomegaly, hypoglycemia, hyperuricemia, and lactic acidemia. To elucidate a spectrum of the G6Pase gene mutations and their frequencies, we analyzed mutations in 51 unrelated Japanese patients with GSD-Ia. The most prevalent mutation was g727t, accounting for 88 of 102 mutant alleles examined, followed by R170X mutation, which accounted for 6 mutant alleles, and R83H mutation which was observed in 3 mutant alleles. In addition, 3 different, novel mutations, IVS1-1g<a, Gly122-to-Asp (G122D) and His179-to-Pro (H179P), were identified. We were able to detect "ectopically" transcribed G6Pase-mRNA in Epstein-Barr virus-transformed lymphoblastoid cells and observed aberrant mRNA splicing associated with the g727t and IVS1-1g<a mutations. To our knowledge, this is the first report that ectopic expression can be utilized for the characterization of GSD-Ia mutations. Our findings suggest that a screening for the g727t, R170X, and R83H mutations by simple DNA-based diagnostic methods can detect 95% of the G6Pase mutant alleles in Japanese patients with GSD-Ia, and remaining mutations can be identified and characterized by the direct sequencing of genomic DNA and/or the analysis of ectopically expressed mRNA. The noninvasive molecular diagnosis for GSD-Ia may ultimately replace the conventional means of enzymatic diagnosis that requires liver biopsy.

A 130-kDa membrane protein of sperm flagella is the receptor for asterosaps, sperm-activating peptides of starfish Asterias amurensis

Spermatozoa of the starfish, Asterias amurensis, have a specific receptor for asterosap, a sperm-activating peptide isolated from the jelly coat of homologous eggs. We characterized the receptor by using several asterosap derivatives. Analysis of equilibrium binding of radioactive di-iodinated Bolton-Hunter reagent-labeled asterosap ((125)I(2)-BHP15) to the spermatozoa indicated that the cell has 1.1 x 10(5) binding sites of high affinity (K(d) = 57 pM), and also the receptor showed positive cooperativity for asterosap binding. When spermatozoa were treated with fluorophore-labeled asterosap, the sperm flagella were labeled, indicating that the receptors are mostly localized in the sperm tail. When spermatozoa were reacted with radioactive asterosap prelabeled with photoaffinity cross-linkers, a single 130-kDa membrane protein of sperm flagella was specifically radiolabeled. This result was reproducible regardless of the length of spacer arm of cross-linkers so far studied. Therefore, the 130-kDa protein is likely to be the receptor for asterosaps. Modification of asterosap at the N-terminal region with bulky molecules such as carboxyfluorescein did not affect the activity of asterosap, suggesting that the N-terminus of asterosap is not involved in the ligand-receptor interaction. On the other hand, S-alkylated asterosaps did not compete with (125)I(2)-BHP15 for binding to the receptor, indicating that disulfide linkage of asterosap is essential for the ligand-receptor interaction. The properties of the receptor, high affinity and high concentration, enabled us to apply the fluorescence polarization technique to study the molecular interaction between asterosap and the receptor. Using this method, we performed binding experiments in almost real time and found that divalent cations are significantly involved in the interaction between asterosap and the receptor.

[A case of spinal muscular atrophy with marked calf hypertrophy and adolescent onset]

We report on a 41-year-old male patient with spinal muscular atrophy (SMA). He had slowly progressive muscular weakness and hypertrophic calves since 14 years of age. The upper arms were slightly, and the thighs moderately atrophic, but the calves were remarkably hypertrophic. There was muscle weakness of both the upper and lower limbs, being more proximal in distribution. He had a positive Gowers' sign and his gait was slightly waddling. Serum creatine kinase level was elevated (518IU/l). Electromyogram revealed a neurogenic pattern. Muscle biopsy of the left biceps brachii showed chronic neurogenic changes. Immunohistochemical examination and Western blot analysis using anti-dystrophin antibodies showed no abnormality. DNA analysis with multiplex PCR proved no deletion in the dystrophin gene, while deletions of exons 7 and 8 of the telomeric copy of survival motor neuron gene were detected. In 1978, Pearn et al. described a new variant syndrome of SMA, characterized by adolescent onset, gross hypertrophy of calves, and a slowly progressive clinical course. The present case is compatible with this syndrome. Therefore, it is suggested that this syndrome, mimicking Becker muscular dystrophy, is not an independent clinical entity, although the phenotype of this syndrome is different from that of typical SMA.

A case of chronic infantile type of fucosidosis: clinical and magnetic resonance image findings

Fucosidosis is a rare autosomal recessive disorder resulting from a deficiency of alpha-L-fucosidase. In this report, we describe clinical and magnetic resonance image (MRI) findings of a chronic infantile type patient heterozygous for a nonsense mutation and a large deletion. The disease onset occurred at 2-3 years of age. She was bound to a wheelchair at 6 years of age, and developed dystonia at the age of 13 years. Brain MRI at 13 years of age showed marked cerebral and cerebellar atrophy, high intensities in the white matter of the frontal and occipital lobes, and low intensities of the bilateral thalamus, striatum, substantia nigra, red nucleus and mamillary bodies on T2-weighted images. The low intensities of basal ganglia on T2-weighted images seems characteristic of lesions in fucosidosis.

Synthesis and anti-HIV activity of arylpiperazinyl fluoroquinolones: a new class of anti-HIV agents

Synthesis and anti-HIV activity of a series of novel arylpiperazinyl fluoroquinolones are reported. In the SAR study, the aryl substituents on the piperazine nitrogen were found to play an important role for the anti-HIV-1 activity. A few of the compounds exhibited potent anti-HIV activity: IC50=0.06 microM in chronically infected cells.

Mutation analysis of a Japanese patient with fucosidosis

Fucosidosis is a rare autosomal recessive disorder resulting from a deficiency of alpha-L-fucosidase. Recently, various mutations have been reported in this disease, but it is difficult to elucidate the phenotype from the genetic mutations. We report a patient with chronic infantile type fucosidosis, with a compound heterozygote of a nonsense mutation (W148X, Trp at codon 148 to stop codon) and a large deletion, including all exons. This is the first report of a large deletion demonstrated in fucosidosis. It is interesting that this patient has a relatively mild clinical course despite the absence of the mRNA. This case also indicates the difficulty in determining the phenotype from the genotype in fucosidosis.

Remission of progressive multifocal leukoencephalopathy following highly active antiretroviral therapy in a patient with HIV infection

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease resulting from lytic infection of oligodendrocytes by the papovavirus JC (JCV). PML has also been recognized as an AIDS-defining illness. The incidence of PML has increased since 1987 and it occurs in up to 4% of patients with AIDS. To date, there is no treatment available for PML and it usually results in death within 3-6 months of diagnosis. However, there are some reports of remission of PML after antiretroviral therapy. We report a 12-year-old child with hemophilia B and developing AIDS with the onset of PML. With highly active antiretroviral therapy, PML subsided with an increase of CD4 count from 10 to 300/microl in spite of about 1.0 X 10(4) human immunodeficiency virus (HIV)-1-RNA copies. He has survived more than 1 year without specific therapy against JCV. Highly active antiretroviral therapy appears to have improved his prognosis in HIV-associated PML.

Sequence analysis of cDNAs encoding precursors of starfish asterosaps

To understand how starfish sperm activating peptides (asterosaps) are synthesized in the ovary, we cloned cDNAs encoding asterosaps and elucidated their nucleotide sequences. The mRNA encoding asterosaps was synthesized only in the oocytes, but not in the follicle cells, and the length was 3.7 kb. The cDNA clones contained multiple isoforms of asterosaps. We assume that asterosap precursors are large prepolypeptide chains with an unusual "rosary-type" structure made of 10 successive similar stretches of 51-55 residues. Each stretch finishes with a "spacer" of 17-21 residues immediately followed by the sequence of one asterosap isoform. The N-terminal of this precursor has 19-21 successive glutamine-rich repeating units. Maturation of the precursor may require endopeptidases that cleave both C- and N-sites of lysine-arginine.

Undetectable dystrophin can still result in a relatively benign phenotype of dystrophinopathy

We present here a 28-year-old male patient with Becker muscular dystrophy whose skeletal muscle showed an absence of dystrophin. He has had progressive and predominantly proximal muscular wasting since 5 years of age, but was able to walk until 26 years of age. He showed hypertrophic calves, cardiomyopathy, and an elevated serum creatine kinase level (934 U/1). A skeletal muscle biopsy revealed advanced chronic myopathic changes. Immunohistochemical examination using anti-dystrophin antibodies against C-terminus showed deficiency of the protein. Rod domain and N-terminus were also absent in almost all muscle fibers, but only in a small part of the sample, they were faintly stained. beta-Dystroglycan and utrophin were present only in a small number of muscle fibers. DNA and RT-PCR analysis showed a frame-shift deletion of exons 3-7 in the dystrophin gene. In such an exceptional case as this one, it is important to investigate the factors which determine the severity of dystrophinopathy.

Molecular heterogeneity of Krabbe disease

Krabbe disease (globoid cell leukodystrophy) is an autosomal recessive neurodegenerative disorder that affects both the central and peripheral nervous system due to an enzymatic defect of galactocerebrosidase (GALC). Following its cloning, many mutations in the galactocerebrosidase gene have been reported, but the correlation between phenotype and genotype was not clear in many cases. In this study we further investigated the molecular defects in another 10 patients (6 Japanese and 4 non-Japanese), using cultured skin fibroblasts, and found 10 mutations, of which 8 were novel, including a nonsense mutation (W647X) and 7 missense mutations (G43R, S52F, T262I, Y319C. W410G, R515H, T652R) in the coding region. Some phenotype-specific mutations were found but the other mutations were private. Mutations reported so far have been distributed over the whole GALC gene and it is difficult to speculate on functional domains of the GALC protein and phenotypically specific regions.

Ion channels in sperm physiology

Fertilization is a matter of life or death. In animals of sexual reproduction, the appropriate communication between mature and competent male and female gametes determines the generation of a new individual. Ion channels are key elements in the dialogue between sperm, its environment, and the egg. Components from the outer layer of the egg induce ion permeability changes in sperm that regulate sperm motility, chemotaxis, and the acrosome reaction. Sperm are tiny differentiated terminal cells unable to synthesize protein and difficult to study electrophysiologically. Thus understanding how sperm ion channels participate in fertilization requires combining planar bilayer techniques, in vivo measurements of membrane potential, intracellular Ca2+ and intracellular pH using fluorescent probes, patch-clamp recordings, and molecular cloning and heterologous expression. Spermatogenic cells are larger than sperm and synthesize the ion channels that will end up in mature sperm. Correlating the presence and cellular distribution of various ion channels with their functional status at different stages of spermatogenesis is contributing to understand their participation in differentiation and in sperm physiology. The multi-faceted approach being used to unravel sperm ion channel function and regulation is yielding valuable information about the finely orchestrated events that lead to sperm activation, induction of the acrosome reaction, and in the end to the miracle of life.

A new fluoroquinolone derivative exhibits inhibitory activity against human immunodeficiency virus type 1 replication

The inhibitory activity of several fluoroquinolone antibiotics against human immunodeficiency virus type 1 (HIV-1) replication was investigated. R-71762, (+/-) 9-fluoro-3-fluoromethyl-2, 3-dihydro-10-[4-(2-pyridyl)-1-piperazinyl]-7-oxo-7H-pyrido[1,2, 3-de][1,4]benzoxazine-6-carboxylic acid, protected MT-4 cells from HIV-1-induced cytopathic effects. Furthermore, the compound inhibited virus replication both in acutely and in chronically HIV-1-infected cells. On the other hand, ofloxacin, levofloxacin, ciprofloxacin, norfloxacin and enoxacin, that were previously reported to be protective against HIV-1-induced cytopathic effects, did not show any protective activity in our assay system. These results indicate that R-71762 is a novel inhibitor of HIV-1 replication and is effective even in HIV-1 chronically infected cells.

Biologically active oligodeoxyribonucleotides. Part 11: The least phosphate-modification of quadruplex-forming hexadeoxyribonucleotide TGGGAG, bearing 3-and 5-end-modification, with anti-HIV-1 activity

We have found that a hexadeoxyribonucleotide (5'TGGGAG3', R-95288), Koizumi, M. et al. Bioorganic & Medicinal Chemistry, 1997, 5, 2235, bearing a 3,4-dibenzyloxybenzyl (3,4-DBB) group at the 5'-end and a 2-hydroxyethylphosphate at the 3'-end, has high anti-HIV-1 activity and the least cytotoxicity in vitro and in vivo. In order to synthesize more potent hexadeoxyribonucleotides, we substituted phosphodiester (P-O) bonds in the 6-mer with the least phosphorothioate (P-S), phosphoramidate (P-N), or methylphosphonate (P-Me) bonds. When more than two P-N or P-Me bonds were introduced into a 6-mer, the phosphate-modified 6-mers had weak or no anti-HIV- activity, in spite of quadruplex structure formation. However, when P-S bonds were substituted for P-O bonds, anti-HIV-1 activity of their 6-mers did not dramatically decrease, compared with compounds substituted with P-N or P-Me bonds. The results suggest that the formation of a quadruplex structure is not always sufficient for anti-HIV-1 activity of the 6-mer, and that net negative charges derived from P-O or P-S bonds in the quadruplex are important for anti-HIV-1 activity. Moreover, among various phosphate-modified ODNs, we found that the anti-HIV-1 activity of ODN PS7 with only one P-S bond was the same as that of R-95288, both having a high stability in human plasma.

Mutational analyses in four Japanese families with X-linked liver phosphorylase kinase deficiency type 1

We analysed the gene of the human alpha-subunit of liver phosphorylase kinase (PHKA2) in four Japanese families with X-linked liver phosphorylase kinase deficiency type 1 by RT-PCR followed by PCR-single-strand conformation polymorphism and direct DNA sequencing. In this study, two novel mutations (Y116D and 2675A-->G) and one mutation previously reported (P1205L) were identified, revealing molecular heterogeneity in Japanese patients. Considering the dissimilarity in phenotype among our patients even with an identical mutation in the PHKA2 gene, it seems that each genetic deficiency in this gene may not be the only factor to determine the clinical heterogeneity in this disease.

Biologically active oligodeoxyribonucleotides. 5. 5'-End-substituted d(TGGGAG) possesses anti-human immunodeficiency virus type 1 activity by forming a G-quadruplex structure

A series of hexadeoxyribonucleotides (6-mers), d(TGGGAG), substituted with a variety of aromatic groups at the 5'-end were synthesized and tested for anti-human immunodeficiency virus type 1 (HIV-1) activity. While unmodified d(TGGGAG) (31) had no anti-HIV-1 activity, compound 23 with a 3,4-di(benzyloxy)benzyl (DBB) group at the 5'-end potently inhibited the HIV-1IIIB-induced cytopathicity of MT-4 cells in vitro (IC50 = 0.37 microM) without cytotoxicity up to 40 microM. A thermal denaturation study on the 5'-end-substituted 6-mers by means of the circular dichroism (CD) spectra demonstrated that the aromatic substituent attached at the 5'-end of the 6-mer strongly enhanced the formation of a parallel helical structure consisting of four strands (quadruplex). On the contrary, compound 36, in which one of the guanosines of 23 was replaced by a thymidine, did not form a quadruplex, thus exhibiting no anti-HIV-1 activity. Moreover, both compound 15, with a tert-butyldiphenylsilyl group solely at its 3'-end, and compound 21, with a relatively small substituent, a benzyl group, at the 5'-end, formed quadruplexes but had no anti-HIV-1 activity. These findings led us to the conclusion that both the quadruplex structure and the aromatic substituent with adequate size at the 5'-end are crucial for the interaction of the 5'-end-substituted 6-mers with the V3 loop as well as the CD4 binding site on viral gp120, resulting in anti-HIV-1 activity.

Structure-activity relationship of HIV-1 protease inhibitors containing AHPBA. Part III: Modification of P2 site

The structure-activity relationship of HIV-1 protease (HIV-1 PR) inhibitors containing AHPBA (3-amino-2-hydroxy-4-phenylbutanoic acid) is discussed. In order to solve the problem of poor oral bioavailability, small-sized dipeptide HIV-1 protease inhibitors containing cyclic urethanes or benzamides at the P2 site were designed and prepared. The substitution patterns of the benzamides contributed significantly to their HIV-1 PR inhibitory activities, and it was shown that the choice of P2-residues was very important. Highly potent inhibitors possessing subnanomolar IC50 values and exhibiting good antiviral potency have been identified. In this class, inhibitor 18 was the most potent (IC90 (CEM/HIV-1 IIIB) 0.11 microM) and showed good oral bioavailability in dogs.

Suppressed UDP-galactose: ceramide galactosyltransferase and myelin protein mRNA in twitcher mouse brain

The developmental changes in expression of steady-state mRNA that encode proteins that are important for myelination (myelin basic protein, myelin-associated glycoprotein, proteolipid protein, UDP-galactose: ceramide galactosyltransferase) and glial fibrillary acidic protein were investigated in the brain of the twitcher mouse, a model of human globoid cell leukodystrophy. This disease is caused by a mutation in the gene encoding the lysosomal enzyme, galactosylceramidase, which catalyzes the degradation of the myelin lipid galactosylceramide. Before postnatal day (PND) 20, the levels of myelin protein mRNA were similar in twitcher and normal mice. With progression of demyelination after PND 25-30, myelin protein mRNA levels gradually decreased. The period of maximum expression of the myelin protein genes in twitcher mice was, however, similar to that of normal control mice. mRNA levels for the gene that encodes the enzyme UDP-galactose:ceramide galactosyltransferase which is responsible for catalyzing the final step in galactosylceramide synthesis, was exceptionally down-regulated from the early stages of the disease. The increase of glial fibrillary acidic protein (GFAP) mRNA levels preceded morphological evidence of demyelination.

Human galactocerebrosidase gene: promoter analysis of the 5'-flanking region and structural organization

Galactocerebrosidase (GALC; EC 3.2.1.46) is a lysosomal enzyme which hydrolyzes several galactolipids and the deficiency of GALC is responsible for Krabbe disease. Recently, we cloned cDNAs for human and murine GALC. In this study we characterized the genomic organization and the promoter of the human gene. The gene was about 60 kb in length and consisted of 17 exons as reported by Luzi et al. DNA sequence analysis showed that the 5'-flanking region of the first exon was GC-rich and had not typical TATA-box but ten GC-box-like sequences within a 200 bp sequence upstream from the initiation codon. Another inframe ATG, which has better Kozak consensus sequence, was found at 48 bp upstream to the first ATG reported]. Promoter analysis using a luciferase assay in COS 7 cells showed that the -149 to -112 nucleotide (from the initiation codon A) region has dominant promoter activity. In this region three GC-box-like sequence and one YY1 binding site were detected. Primer extension revealed several transcription start sites within the region of -146 to -103 nucleotide. In this study we firstly demonstrated that the YY1 binding site and subsequent GC-box-like sequences could be a promoter in a housekeeping gene.

Biologically active oligodeoxyribonucleotides. 10: anti-HIV-1 activity and stability of modified hexanucleotides containing glycerol-skeleton

Deoxyribose-moieties of modified hexadeoxyribonucleotide 1, which exhibits anti-HIV-1 activity, were partially replaced with glycerol-moieties. Compound 7 with two glycerylguanines at its 3'-end showed more potent anti-HIV-1 activity and more stability against digestion by nucleases than the parent compound 1.

Design and anti-HIV-1 activity of hammerhead and hairpin ribozymes containing a stable loop

Three ribozymes, a hairpin ribozyme (HR112) and two hammerhead ribozymes (RZ115 and RZ119) containing a 5'C(UUCG)G3' loop were designed to cleave the U5 region in the long terminal repeat (LTR) of HIV-1 RNA. The t1/2 values of chemically synthesized substrates mediated by three ribozymes were measured. The transformed CEM cells possessing these three ribozyme-encoding genes were challenged with a HIV-1IIIB strain, and two of these three ribozymes, HR112 and RZ119, were shown to possess strong anti-HIV-1 activity.

Biologically active oligodeoxyribonucleotides--IX. Synthesis and anti-HIV-1 activity of hexadeoxyribonucleotides, TGGGAG, bearing 3'- and 5'-end-modification

We have determined that hexadeoxyribonucleotides (5'TGGGAG3'), with modified aromatic groups such as a trityl group at the 5'-end, have anti-HIV-1 activity in vitro. The 6-mer bearing a 3,4-dibenzyloxybenzyl (3,4-DBB) group at the 5'-end had the most potent activity and the least cytotoxicity. When the 3'-end of the 5'-(3,4-DBB)-modified 6-mer was substituted with a 2-hydroxyethylphosphate, a 2-hydroxyethylthiophosphate, or a methylphosphate group at the 3'-end, anti-HIV-1 activity increased. Moreover, among various 3'- and 5'-end-modified 6-mers that were tested, the 6-mer (R-95288) bearing a 3,4-DBB group at the 5'-end and a 2-hydroxyethylphosphate group at the 3'-end was the most stable, when incubated with mouse, rat, or human plasma. Therefore, R-95288 was chosen as the best candidate for possible use in therapy on the basis of its anti-HIV-1 activity.

Characterization of one monoclonal antibody against feline immunodeficiency virus p24 and its application to antigen capture ELISA

Several monoclonal antibodies (mAbs) were produced against feline immunodeficiency virus (FIV) p24 capsid antigen. One of these, F2710, reacted strongly, not only with viral p24 and recombinant p24, but also with p50 Gag precursor protein in Western blot. Epitope mapping analysis revealed that mAb F2710 recognizes a heptapeptide, SFIDRLF, in the FIV p24 amino acid sequence. As this portion of FIV p24 is highly conserved among various FIV strains, the mAb seems to be a useful tool for detecting FIV p24 antigen in various samples. By means of this mAb and rabbit anti-p24 polyclonal antibody, an antigen capture ELISA was developed. The ELISA detected viral p24 antigen with good linearity. The lower detection limit of this assay is 40 pg/ml of recombinant p24 antigen, which is at least as sensitive as the reverse transcriptase assay in detecting FIV virion. Thus, this system is valuable for monitoring FIV replication in vitro.

Development of HIV-1 protease expression methods using the T7 phage promoter system

New and simple human immunodeficiency virus type 1 (HIV-1) protease expression methods in Escherichia coli were developed using the T7 phage promoter system. In order to suppress leaky HIV-1 protease expression under the control of the T7 polymerase, two new methods were tested. One involved the introduction of supplementary T7 promoter regions into host cells [E. coli BL-21 (DE3)] containing the HIV-1 protease gene under the control of the T7 promoter. It was expected that the supplementary T7 promoter regions would compete with the HIV-1 protease expression vector for the T7 polymerase binding. The other involved the infection of late-log-phase cultures of E. coli JM109 harboring the same HIV-1 protease expression vector with the M13 phage expressing T7 polymerase. Both methods were effective, and transformants with the mature HIV-1 protease expression vector showed ten times higher HIV-1 protease activity than activities obtained with the autoprocessing vector. The expression systems described here are convenient and are also easily applicable for the expression of other proteins toxic for E. coli.

In vitro and ex vivo anti-human immunodeficiency virus (HIV) activities of a new water-soluble HIV protease inhibitor, R-87366, containing (2S,3S)-3-amino-2-hydroxy-4-phenylbutanoic acid

In a series of compounds containing (2S,3S)-3-amino-2-hydroxy-4-phenylbutanoic acid (AHPBA), a transitionstate mimetic, R-87366:(2S,3S)-3-[N-(quinoxaline-2-carbonyl)-L-asparaginyl]amino- 2-hydroxy-4-phenylbutanoyl-L-proline tert-butylamide, was found to be a potent human immunodeficiency virus protease inhibitor (Ki value was 11 nM) and anti-HIV agent (IC90 value was 0.5 microM for HIV-1IIIB acutely infected cells) with moderate water-solubility (4.2 mg/ml at 25 degrees C). The compound was also active in chronically infected Molt-4/HIV-1IIIB cells, and inhibited the proteolytic processing of p55 into p17, suggesting that its anti-HIV activity was derived from HIV protease inhibition. The compound showed more potent activity (IC90 value was 0.03-0.25 microM) against clinical isolates of HIV in 5 out of 6 patients examined with varying clinical status in an ex vivo assay. One isolate, however, from the sixth patient, was less sensitive to R-87366 (IC90 value was 0.5 microM). In experiments with this strain, R-87366 showed comparatively low efficacy in acutely infected peripheral blood mononuclear cell (PBMC). This result suggests that the diversity of sensitivity shown in the ex vivo assay could be caused by the viral property itself. As a result of the determination of nucleic acid sequences in the clinical isolates, some amino acids were found to be substituted in the protease region, in contrast to the HIV-1 clade B consensus sequence, and some of them have been reported to contribute to the susceptibility of HIV protease inhibitors.

Inhibition of HIV-1 protease by oxim derivatives

In cell-free proteolytic processing using recombinant HIV-1 protease and Gag precursor polypeptide, certain simple oxim derivatives containing halogenomethylketone and phenyl moieties displayed HIV-1 protease inhibitory activity. Their Ki values ranged from 2.1 microM to 6.3 microM and they did not inhibit significantly other aspartic acid proteases. Both the halogenomethylketone moiety and the oxim structure were essential for the observed inhibition. Molecular modeling analysis suggested that these compounds are recognized by the HIV-1 protease as the P1 and P1' part of the substrate. In addition, one potent derivative showed inhibition of viral maturation in HIV-1IIIB chronically infected Molt-4 cells. These results indicate that it is possible to develop new and specific nonpeptidyl HIV protease inhibitors of low molecular weight.

Structure-activity relationships of HIV-1 PR inhibitors containing AHPBA--II. Modification of pyrrolidine ring at P1' proline

Systematic replacement in the 3- or 4-position of the pyrrolidine ring at P1' proline was carried out. Compound 26, which has a Cl atom in the 4(S)-position was the most active among inhibitors substituted with other halogen atoms or other substituents. Furthermore, the replacement of the Z group in compound 26 with five- or six-membered fused aromatic heterocycle carbonyl groups produced more potent inhibitors. 7-Methoxybenzofuran-2-carbonyl derivative (44) was the best of these and showed Ki = 4.5 nM against HIV PR and IC90S 0.58 microM and 0.06 microM in chronic and acute infections, respectively. These results suggest that the combination of the 4(S)-CI atom and fused bicyclic heterocycles may be effective in improving their cellular penetration.

Structure and function of asterosaps, sperm-activating peptides from the jelly coat of starfish eggs

Jelly coat of starfish eggs has the capacity to activate homologous spermatozoa and induce the acrosome reaction. We have isolated 12 sperm-activating peptides (SAPs) from the egg jelly of the starfish, Asterias amurensis. Eleven SAPs were structurally identified by sequence analysis and electro-spray ionisation mass spectrometry. All of them are glutamine-rich tetratriacontapeptides with an intramolecular disulphide linkage between Cys8 and Cys32. They are much larger than sea urchin SAPs and do not show any significant sequence similarities to known proteins. Thus we have collectively named them asterosaps. The amino terminal region, where structural diversity of asterosaps is observed, is not important for their activity, whereas the disulphide linkage is essential. Asterosaps do not induce the acrosome reaction by themselves, but are able to induce the acrosome reaction in combination with an egg jelly glycoconjugate named ARIS. Furthermore, anti-asterosap rabbit antibody significantly decreased the acrosome reaction-inducing activity of the jelly solution and the activity was restored by addition of excess asterosap. These results support our hypothesis that the main physiological role of SAPs is the induction of the acrosome reaction in cooperation with two other jelly components, ARIS and Co-ARIS.

Guanine-rich oligonucleotide modified at the 5' terminal by dimethoxytrityl residue inhibits HIV-1 replication by specific interaction with the envelope glycoprotein

Previous studies have shown that a guanine-rich oligonucleotide SA-1042, DmTr-TGGGAGGTGGGTCTG, neutralizes HIV-1 infectivity, blocks syncytium formation and inhibits the binding of recombinant gp120 to immobilized soluble CD4 in vitro (Furukawa et al., 1994). We have now investigated the precise mode of action of SA-1042. We show here that SA-1042 specifically antagonizes the binding of anti-V3 loop antibodies or anti-CD4 binding-site antibodies to recombinant gp120, and also blocks the binding of an anti-V3 loop antibody to the V3 peptide (gp120IIIB: aa302-324). In contrast, SA-1042 does not inhibit gp120 binding of monoclonal antibodies directed to other regions of gp120, such as the conserved N-terminal regions (gp120IIIB: aa35-108 or gp120IIIB: aa72-130) or the C-terminal region (gp120IIIB: aa481-496). Furthermore, SA-1042 does not interfere with the binding of monoclonal antibodies directed to other molecules, gp41, CD4, CD11a, CD18, CD26, CD44 or CD54. These data suggest that SA-1042 exerts its antiviral effects by targeting the V3 loop as well as the CD4 binding site on gp120.

Molecular cloning and expression of cDNA for murine galactocerebrosidase and mutation analysis of the twitcher mouse, a model of Krabbe's disease

The cDNA for a murine galactocerebrosidase was isolated from a murine testis cDNA library on the basis of its homology with the cDNA for human galactocerebrosidase and a PCR method was used to clone the 5' end. It has a 2,278-nucleotide sequence including a 2,004-nucleotide open reading frame, which encodes 668 amino acid residues. The identity between the human and murine amino acid sequences was very high, being calculated to be 84%. Sequencing of cDNA from liver of the twitcher mouse revealed a nonsense mutation at codon 339 (TGG-->TGA). The most abundant mRNA of the murine galactocerebrosidase gave a 3.6-kb band, which was not detected in twitcher mice. This suggests that the cDNA (2,278 bp) we characterized represents a minor species generated by an alternate poly(A) signal and that most of the mRNA has a much longer 3'-untranslated region. Genome analysis revealed that this mutation was homozygous in the twitcher and heterozygous in the carrier but was not present in normal mice. The normal mouse cDNA but not the mutant cDNA of the galactocerebrosidase transfected into COS1 cells gave rise to an increase in enzymatic activity. We concluded that this mutation results in the deficiency of galactocerebrosidase in the twitcher mouse.

Molecular defects in Krabbe disease

Krabbe disease (globoid cell leukodystrophy) is an autosomal recessive neurodegenerative disorder that affects both the central and peripheral nervous systems due to an enzymatic defect of the galactocerebrosidase. In this study, molecular defects in Krabbe disease were investigated in 11 patients (seven Japanese and four non-Japanese) using cultured skin fibroblasts. A Japanese late infantile patient had a missense mutation of Pro at codon 302 to Ala and a non-Japanese patient had a missense mutation of Val at codon 550 to Gly. The reduced enzymatic activities expressed from the cDNAs with these missense mutations and from the previously reported nonsense mutation (E369X, Glu at codon 369 to stop codon) were confirmed. Genomic DNA analyses revealed that the P302A and E369X mutations were heterozygous and the V550G mutation was homozygous in these patients. A 12 base deletion with a 3 base insertion was found in three unrelated Japanese infantile patients, but not in 30 controls. The mutation was homozygous in two patients and heterozygous in one patient. We could not find any confirmed mutation in the coding region in the other six patients. These findings suggest that mutations in infantile and late infantile patients are relatively heterogeneous.

Design and anti-HIV-1 activity of ribozymes that cleave HIV-1 LTR

A hairpin ribozyme (HR112) and two hammerhead ribozymes (RZ115 and RZ119) containing a 5'C(UUCG)G3' loop were designed to cleave the long terminal repeat (LTR) of HIV-1. When the ribozyme catalyzed RNA cleavage reaction for a chemically synthesized 19 mer (LTR 19) was measured, the t 1/2 value of LTR 19 mediated by RZ115 was smaller than that of the RZ119 case. Moreover, the transformed CEM cells harboring the gene encoding these ribozymes were challenged with a HIV-1IIIB strain, two ribozymes, HR112 and RZ119 possessed strong anti-HIV-1 activity. However, the anti-HIV-1 activity displayed by RZ115 was weak. On the basis of secondary structure predictions of the RNA transcribed with the gene encoding ribozymes, the secondary structure of the transcribed RNA with RZ115 sequences was observed to be different from those with the other ribozymes. It has been demonstrated that the secondary structures of transcribed RNAs can possibly influence the anti-HIV-1 activity.

Electron microscopic studies on the inhibition of degranulation of rat mast cells by a novel anti-allergic agent, PTPC

When rat mast cells sensitized by IgE antibody were exposed to antigen, transmission electron microscopy revealed alteration of the granules, cavity formation by fusion of the perigranular membrane and granule release by the fusion of the cavity membrane with the mast cell membrane. Scanning electron microscopy disclosed the extrusion of smooth and round bodies from pores formed on the cell surface. These changes were accompanied by the release of histamine. The inhibition of this degranulation by a novel anti-allergic agent, 6-(1-pyrrolidinyl)-N-(1H-tetrazol-5-yl)-2-pyrazinecarboxamide (PTPC), was evaluated quantitatively as an inhibition of the granule alteration and cavity formation. At a concentration of 100 nM, PTPC inhibited the granule alteration and cavity formation as well as histamine release. In the same concentration, PTPC significantly increased the cyclic AMP content in the mast cells. These results suggest that the inhibition of the morphological changes in mast cells by PTPC might be due to the increased cyclic AMP caused by the agent and plays an important role in the suppression of chemical mediators release.