Cytochemical analysis of storage materials in cultured skin fibroblasts from patients with I-cell disease.

Background: In cultured fibroblasts from I-cell disease patients the transport of many lysosomal enzymes is defective, and affected cells contain inclusion bodies filled with undegraded substrates. However, the contents of these inclusion bodies have not been well characterized yet. We attempted to identify accumulated substances in cultured I-cell disease fibroblasts cytochemically.

Hsp90 inhibitors suppress HCV replication in replicon cells and humanized liver mice.

Persistent infection with hepatitis C virus (HCV) is a major cause of liver diseases such as chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. Here we report that inhibition of heat shock protein 90 (Hsp90) is highly effective in suppressing HCV genome replication. In HCV replicon cells, HCV replication was reduced by Hsp90 inhibitors and by knockdown of endogenous Hsp90 expression mediated by small-interfering RNA (siRNA).

SARS-CoV spike protein-expressing recombinant vaccinia virus efficiently induces neutralizing antibodies in rabbits pre-immunized with vaccinia virus.

A vaccine for severe acute respiratory syndrome (SARS) is being intensively pursued against its re-emergence. We generated a SARS coronavirus (SARS-CoV) spike protein-expressing recombinant vaccinia virus (RVV-S) using highly attenuated strain LC16m8. Intradermal administration of RVV-S into rabbits induced neutralizing (NT) antibodies against SARS-CoV 1 week after administration and the NT titer reached 1:1000 after boost immunization with RVV-S.

Genetic factors in the treatment of bronchial asthma.

Owing to the recent vast progress in analytical tools and procedures to elucidate the relationship between genes and diseases, many candidate genes leading to the development of bronchial asthma have been reported. However, the quantitative phenotypes of asthma, such as decrease in forced expiratory volume in the first second, serum hyper-IgE, bronchial hyperresponsiveness and blood hyper-eosinophilia, do not represent this disease completely. On the other hand, eosinophilic inflammation of the bronchial mucosa represents accurately the feature of bronchial asthma, although accurate quantification of its status is difficult.

Phospholipid storage in the myocardium of a unique Japanese case of idiopathic cardiomyopathy.

Background: A unique adult male patient who developed cardiomyopathy was first suspected to have cardiac Fabry disease based on the pathological findings in heart tissues obtained on biopsy, but the alpha-galactosidase activity in his leukocytes was normal and no mutation was detected in the coding region of the alpha-galactosidase gene. We identified accumulated materials in the myocardium of this patient.

Methods: Pathological and biochemical analyses were performed using the autopsied heart tissues as samples.

Serine palmitoyltransferase inhibitor suppresses HCV replication in a mouse model.

Serine palmitoyltransferase (SPT) is a first-step enzyme in the sphingolipid biosynthetic pathway. Myriocin is an inhibitor of SPT and suppresses replication of the hepatitis C virus (HCV) replicon. However, it is still unknown whether this SPT inhibitor suppresses HCV replication in vivo.

[Impairment of the ubiquitin-proteasome system and neurodegeneration].

There are growing lines of evidence addressing the importance of the ubiquitin-proteasome system (UPS) that catalyzes various biological reactions rapidly, methodically, exhaustively, and unidirectionally. UPS is responsible for a diverse array of biologically important cellular processes, such as cell-cycle progression, signaling cascades and developmental programs. This system is also involved in the protein quality control, which maintains the homeostasis of the cell.

Capillary morphogenesis gene (CMG)-1 is among the genes differentially expressed in mouse male germ line stem cells and embryonic stem cells.

We recently established a technique to expand male germ line stem (GS) cells in long-term culture without losing their spermatogenic capacity. To gain insight into the genetic program of these cells, we compared the mRNA expression profile of GS cells with that of embryonic stem (ES) cells using DNA microarrays. We found 79 genes that were upregulated in GS cells compared to ES cells, including synaptonemal complex protein-1, deleted in azoospermia-like, ubiquitin-conjugating enzyme E2B, and ubiquitin carboxy-terminal hydrolase L1, all of which are functionally important for spermatogenesis.

The orphan nuclear receptor GCNF recruits DNA methyltransferase for Oct-3/4 silencing.

Somatic DNA methylation patterns are determined in part by the de novo methylation that occurs after early embryonic demethylation. Oct-3/4, a pluripotency gene, is unmethylated in the blastocyst, but undergoes de novo methylation and silencing during gastrulation. Here we show that the transcriptional repressor GCNF recruits DNA methyltransferase to the Oct-3/4 promoter and facilitates its methylation.

Characterization of binding activity between nuclear factor of activated T cells and calcineurin by amplified luminescent proximity homogeneous assay.

For quantitative evaluation of the relationship between biological binding partners, including protein-protein interactions, a novel analyzing system, amplified luminescent proximity homogeneous assay (ALPHA), has been developed. We here employed ALPHA for accurate assessment of the binding properties between nuclear factor of activated T cells 1 (NFAT1) and calcineurin (CN), which is essential for Ca2+-dependent regulation of immune responses. A recombinant protein of the Ca2+ regulatory domain (CRD) of NFAT1 was prepared and its binding activity with biotinylated CN was determined by ALPHA (Kd = 0.

Maintenance of Mouse, Rat, and Pig Pancreatic Islet Functions by Coculture with Human Islet-Derived Fibroblasts.

Development of an efficient preculture system of islets is ideal. Toward that goal, we constructed a human pancreatic islet-derived fibroblast cell line MNNK-1 for a source as a coculture system for freshly isolated islets to maintain islet functions. Human pancreatic islet cells were nucleofected with a plasmid vector pYK-1 expressing simian virus 40 large T antigen gene (SV40T) and hygromycin resistance gene (HygroR).

Corrective effect on Fabry mice of yeast recombinant human alpha-galactosidase with N-linked sugar chains suitable for lysosomal delivery.

We have previously reported the production of a recombinant alpha-galactosidase with engineered N-linked sugar chains facilitating uptake and transport to lysosomes in a Saccharomyces cerevisiae mutant. In this study, we improved the purification procedure, allowing us to obtain a large amount of highly purified enzyme protein with mannose-6-phosphate residues at the non-reducing ends of sugar chains. The products were incorporated into cultured fibroblasts derived from a patient with Fabry disease via mannose-6-phosphate receptors.

Intracellular-diced dsRNA has enhanced efficacy for silencing HCV RNA and overcomes variation in the viral genotype.

RNA interference (RNAi) can be used to inhibit viral replication in mammalian cells and therefore could be a powerful new antiviral therapy. Small interfering RNA (siRNA) may be effective for RNAi, but there are some technical problems that must be solved in each case, for example, predicting the effective siRNA target site and targeting heterogeneous sequences in a virus population. We show here that diced siRNA generated from long double-stranded RNA (dsRNA) is highly effective for inducing RNAi in HuH-7 cells harboring hepatitis C virus (HCV) replicons and can overcome variations in the HCV genotype.

[Regulation of the protein degradation pathway by the ubiquitin family: its implication in neurodegenerative diseases].

Growing lines of evidence suggest that the neurodegenerative diseases are tightly linked to the ubiquitin and the proteasome pathway (UPP), which plays a pivotal role in selective protein degradation in the cells. Genetic mutations in the ubiquitin pathway (ie; parkin and Uchll) cause familial Parkinson's disease (PD), and sequestration of such UPP enzymes in the inclusion bodies are observed in not only sporadic forms of PD but also in other neurodegenerative diseases. These evidences place the reduction of UPP as a central mechanism underlying the pathogenesis and progression of neurodegenerative diseases linked to inclusion body formation.

[Regenerative medicine of skeletal muscle].

In the dystrophin-deficient mdx mice, an animal model of Duchenne muscular dystrophy (DMD), damaged skeletal muscles are efficiently regenerated and thus the animals thrive. The phenotypic differences between DMD patients and mdx mice suggest the existence of factors that modulate the muscle wasting in the mdx mice. To identify these factors, we searched for mRNAs affected by the mdx mutation using cDNA microarrays with newly established skeletal muscle cell lines derived from mdx and normal mice.

Comparison of the effects of agalsidase alfa and agalsidase beta on cultured human Fabry fibroblasts and Fabry mice.

We compared two recombinant alpha-galactosidases developed for enzyme replacement therapy for Fabry disease, agalsidase alfa and agalsidase beta, as to specific alpha-galactosidase activity, stability in plasma, mannose 6-phosphate (M6P) residue content, and effects on cultured human Fabry fibroblasts and Fabry mice. The specific enzyme activities of agalsidase alfa and agalsidase beta were 1.70 and 3.

Development of a microscopic platform for real-time monitoring of biomolecular interactions.

We developed a new microscopic platform for the real-time analysis of molecular interactions by combining microbead-tagging techniques with total internal reflection fluorescent microscopy (TIRFM). The optical manipulation of probe microbeads, followed by photo immobilization on a solid surface, enabled us to generate arrays with extremely high density (>100 microbeads in a 25 microm x 25 microm area), and TIRFM made it possible to monitor the binding reactions of fluorescently labeled targets onto probe microbeads without removal of free targets. We demonstrated the high performance of this platform through analyses of interactions between antigen and antibody and between small compounds and proteins.

Large- and small-scale purification of mammalian 26S proteasomes.

The 26S proteasome is an ATP-dependent protease known to collaborate with ubiquitin, whose polymerization acts as a marker for regulated and enforced destruction of unnecessary proteins in eukaryotic cells. It is an unusually large multi-subunit protein complex, consisting of a central catalytic machine (called the 20S proteasome or CP/core particle) and two terminal regulatory subcomplexes, termed PA700 or RP/regulatory particle, that are attached to both ends of the central portion in opposite orientations to form an enzymatically active proteasome. To date, proteolysis driven by the ubiquitin-proteasome system has been shown to be involved in a diverse array of biologically important processes, such as the cell cycle, immune response, signaling cascades, and developmental programs; and the field continues to expand rapidly.

Spermatogonial cell-mediated activation of an IkappaBzeta-independent nuclear factor-kappaB pathway in Sertoli cells induces transcription of the lipocalin-2 gene.

In spermatogenesis, Sertoli cells serve as supporting cells for the proliferation and differentiation of germ cells. However, it appears that Sertoli cell function is regulated by adjacent spermatogonial cells in the testis because expression of lipocalin-2 mRNA, which encodes an iron-siderophore-binding protein, is barely detectable in Sertoli cells of germ cell-deficient W/Wv mice, and more abundantly expressed in jsd/jsd mice. By employing a coculture system comprising immortalized Sertoli cells (designated as Sertoli-B) and c-Kit(+) spermatogonial cells from 7-d-old mouse testis, we found that lipocalin-2 gene transcription in Sertoli cells is induced by a factor secreted from spermatogonial cells.

Organelle degradation during the lens and erythroid differentiation is independent of autophagy.

Autophagy is a bulk degradation system within cells through which cytoplasmic components are degraded within lysosomes. Primary roles of autophagy are starvation adaptation and intracellular protein quality control. In contrast to the ubiquitin-proteasome system, autophagy can also degrade organelles.

Purification and assay of the chaperone-dependent ubiquitin ligase of the carboxyl terminus of Hsc70-interacting protein.

It is notable that both chaperone and ubiquitin-proteasome systems are required for the removal of aberrant cellular proteins to ensure protein homeostasis in cells. However, the entity that links the two systems had remained elusive. The carboxyl terminus of Hsc70-interacting protein (CHIP), originally identified as a cochaperone of Hsc70, has both a TPR motif and a U-box domain.

Expression and assay of glycoprotein-specific ubiquitin ligases.

N-linked glycosylation of proteins that takes place in the endoplasmic reticulum (ER) plays a key role in protein quality control. Misfolded proteins or unassembled protein complexes that fail to achieve their functional states in the ER are retrotranslocated into the cytosol and degraded by the ubiquitin-proteasome system in a process called ER-associated degradation (ERAD). N-linked glycoprotein-specific ubiquitin ligase complexes, SCF(Fbs1) and SCF(Fbs2), appear to participate in ERAD for selective elimination of aberrant glycoproteins in the cytosol.

In vitro systems for NEDD8 conjugation by Ubc12.

Nedd8 is a ubiquitin-like molecule that is highly conserved in eukaryotes. Similar to ubiquitin, Nedd8 attaches to target proteins through an enzymatic cascade composed of Nedd8-specific E1 (activating)- and E2 (conjugating)-enzymes. The E1 for Nedd8 is a heterodimer of APP-BP1 and Uba3, while the E2 is Ubc12.

Interaction of N1,N12-diacetylspermine with polyamine transport systems of polarized porcine renal cell line LLC-PK1.

LLC-PK(1) cells grown on porous membrane filters were employed as a model system to explore the renal transport of polyamines. The polarity of LLC-PK(1) monolayers was confirmed by the exclusive appearance of a Na(+)-dependent alpha-methylglucoside transport system on the apical surface. The uptake of free polyamines from the basolateral side of monolayers was consistent with the existence of a single class of transport system, while the existence of two kinetically distinct polyamine transport systems with higher and lower affinities on apical membranes was suggested.