Biomedical subjects

Takayuki Fukuda

Publications and source records attributed to Takayuki Fukuda.

6 recordsLinked to original sources

PubMed2006

Engineered bio-nanocapsules, the selective vector for drug delivery system.

The bio-nanocapsule (BNC) is our concept of artificial hollow nanoparticles that have been designed and produced through biotechnological procedures. We proposed an empty virus-like particle, which consists of a recombinant L envelope protein of hepatitis B virus (HBV) and a lipid derived from the host cell, as an engineered BNC. Although this BNC was first developed as an immunogen of hepatitis B vaccine, the pre-S1 region in N-terminus of L envelope protein confers hepatocyte specific infectivity of HBV on the BNC. This recombinant BNC is now being developed as a novel platform of drug delivery system (DDS) vector for selective delivery.

Biomedical Engineering↗

PubMed2005

Identification of cell surface marker candidates on SV-T2 cells using DNA microarray on DLC-coated glass.

We analyzed gene expression profiles of normal mouse fibroblast BALB/c 3T3 cells and its SV40 transformant SV-T2 cells using our originally developed cell surface marker DNA microarray, which is prepared on a diamond-like carbon-coated glass. As a result, CD62L and IL-6 receptor alpha gene expressions were upregulated in SV-T2 and were thought to be candidates for call surface markers of the cells. The result of microarray analysis was validated by real-time quantitative PCR immunohistochemistry and biological assays. These data show that our cell surface marker DNA microarray should be useful in finding the candidates of cell type-specific surface markers.

Animals↗

PubMed2005

Methyl-CpG binding protein 2 gene (MECP2) variations in Japanese patients with Rett syndrome: pathological mutations and polymorphisms.

A total of 45 different mutations of methyl-CpG-binding protein 2 gene (MECP2) were identified in 145 of 219 Japanese patients with typical or atypical Rett syndrome (RTT) (66.2%). A missense mutation, T158M was the most common mutation of MECP2, identified in 22 (19.1%) patients, followed by four nonsense mutations, R168X (14.8%), R270X (13.0%), R255X (9.6%), and R294X (6.1%) in 115 patients with classical RTT. Two missense mutations, R133C (33.3%) and R306C (23.3%), and a nonsense mutation, R294X (13.3%), were common in 30 patients with atypical RTT, including the preserved speech variant (PSV). Frameshift mutations due to nucleotide deletion or insertion were identified in 22 patients with MECP2 mutations, and one of them had a 3.6 kb deletion encompassing exons 3 and 4. Three patients with classical RTT had a splicing anomaly. The wide spectrum of phenotypic variability in patients with RTT has been considered to be correlated with the mutation type and location in MECP2, and X-inactivation. However, most patients showed a random X-inactivation pattern evaluated by an androgen receptor gene polymorphism in this study, suggesting that a skewed X-inactivation might not be a main modification factor on clinical phenotypes of RTT. In addition, three new missense mutations, P176R, A378V and T479M, were identified in patients with RTT, but also in healthy Japanese, indicating that these mutations are non-pathogenic in Japanese. Information about rare polymorphic variations is very important for the molecular diagnosis of RTT, although rare polymorphic variants might differ among ethnic groups.

Adolescent↗

PubMed2005

The specific delivery of proteins to human liver cells by engineered bio-nanocapsules.

A bio-nanocapsule (BNC), composed of the surface antigen (sAg) of the hepatitis B virus, is an efficient nanomachine with which to accomplish the liver-specific delivery of genes and drugs. Approximately 110 molecules of sAg are associated to form a BNC particle with an average diameter of 130 nm. The L protein is an sAg peptide composed mainly of preS and S regions. The preS region, with specific affinity for human hepatocytes, is localized in the N-terminus. The S region following the preS has two transmembrane regions responsible for the formation of particles. In this study, the fusion of emerald green fluorescent protein (EGFP) at the C-terminus of the S region was designed to deliver proteins to human hepatocytes. Truncation of the C-terminus of the S region was required to obtain sufficient expression levels in Cos7 cells. The nanoparticles that were produced delivered EGFP to human hepatoma cells, displaying the EGFP moiety outside, or enclosing it inside. However, only a single orientation characterizes the particle, so that either type of L fusion particle could be effectively and independently separated by an antibody affinity column. The dual C-terminal topologies of the L fusion particles designed in this study could be applied to various proteins for the C-terminal moiety of the L fusion proteins, depending on the character of the proteins, such as cytoplasmic proteins, as well as cytokines or ligands to cell surface receptors. We suggest that this fusion design is the most efficient way to prepare a BNC that delivers proteins to specific cells or tissues.

Amino Acid Sequence↗

PubMed2004

Mutations of ARX are associated with striking pleiotropy and consistent genotype-phenotype correlation.

We recently identified mutations of ARX in nine genotypic males with X-linked lissencephaly with abnormal genitalia (XLAG), and in several female relatives with isolated agenesis of the corpus callosum (ACC). We now report 13 novel and two recurrent mutations of ARX, and one nucleotide change of uncertain significance in 20 genotypic males from 16 families. Most had XLAG, but two had hydranencephaly and abnormal genitalia, and three males from one family had Proud syndrome or ACC with abnormal genitalia. We obtained detailed clinical information on all 29 affected males, including the nine previously reported subjects. Premature termination mutations consisting of large deletions, frameshifts, nonsense mutations, and splice site mutations in exons 1 to 4 caused XLAG or hydranencephaly with abnormal genitalia. Nonconservative missense mutations within the homeobox caused less severe XLAG, while conservative substitution in the homeodomain caused Proud syndrome. A nonconservative missense mutation near the C-terminal aristaless domain caused unusually severe XLAG with microcephaly and mild cerebellar hypoplasia. In addition, several less severe phenotypes without malformations have been reported, including mental retardation with cryptogenic infantile spasms (West syndrome), other seizure types, dystonia or autism, and nonsyndromic mental retardation. The ARX mutations associated with these phenotypes have included polyalanine expansions or duplications, missense mutations, and one deletion of exon 5. Together, the group of phenotypes associated with ARX mutations demonstrates remarkable pleiotropy, but also comprises a nearly continuous series of developmental disorders that begins with hydranencephaly, lissencephaly, and agenesis of the corpus callosum, and ends with a series of overlapping syndromes with apparently normal brain structure.

Abnormalities, Multiple↗

PubMed2002

Mutation of ARX causes abnormal development of forebrain and testes in mice and X-linked lissencephaly with abnormal genitalia in humans.

Male embryonic mice with mutations in the X-linked aristaless-related homeobox gene (Arx) developed with small brains due to suppressed proliferation and regional deficiencies in the forebrain. These mice also showed aberrant migration and differentiation of interneurons containing gamma-aminobutyric acid (GABAergic interneurons) in the ganglionic eminence and neocortex as well as abnormal testicular differentiation. These characteristics recapitulate some of the clinical features of X-linked lissencephaly with abnormal genitalia (XLAG) in humans. We found multiple loss-of-function mutations in ARX in individuals affected with XLAG and in some female relatives, and conclude that mutation of ARX causes XLAG. The present report is, to our knowledge, the first to use phenotypic analysis of a knockout mouse to identify a gene associated with an X-linked human brain malformation.

Alleles↗