Yuta Chiba

Dental epithelial stem cells give rise to four types of dental epithelial cells: inner enamel epithelium (IEE), outer enamel epithelium (OEE), stratum intermedium (SI), and stellate reticulum (SR). IEE cells further differentiate into enamel-forming ameloblasts, which play distinct roles, and are essential for enamel formation. These are conventionally classified by their shape, although their transcriptome and biological roles are yet to be fully understood. Here, we aimed to use single-cell RN

There is growing evidence showing that tight junctions play an important role in developing enamel. Claudins are one of the main components of tight junctions and may have pivotal functions in modulating various cellular events, such as regulating cell differentiation and proliferation. Mutations in <i>CLDN10</i> of humans are associated with HELIX syndrome and cause enamel defects. However, current knowledge regarding the expression patterns of claudins and the function of <i>Cldn10</i> during

The development of ectodermal organs, such as teeth, requires epithelial-mesenchymal interactions. Basic helix-loop-helix (bHLH) transcription factors regulate various aspects of tissue development, and we have previously identified a bHLH transcription factor, AmeloD, from a tooth germ cDNA library. Here, we provide both <i>in vitro</i> and <i>in vivo</i> evidence that AmeloD is important in tooth development. We created <i>AmeloD</i>-knockout (KO) mice to identify the <i>in vivo</i> functions

Organ development is dictated by the regulation of genes preferentially expressed in tissues or cell types. Gene expression profiling and identification of specific genes in organs can provide insights into organogenesis. Therefore, genome-wide analysis is a powerful tool for clarifying the mechanisms of development during organogenesis as well as tooth development. Single-cell RNA sequencing (scRNA-seq) is a suitable tool for unraveling the gene expression profile of dental cells. Using scRNA-s

Dental enamel, the hardest tissue in the human body, is derived from dental epithelial cell ameloblast-secreted enamel matrices. Enamel mineralization occurs in a strictly synchronized manner along with ameloblast maturation in association with ion transport and pH balance, and any disruption of these processes results in enamel hypomineralization. G protein-coupled receptors (GPCRs) function as transducers of external signals by activating associated G proteins and regulate cellular physiology.

Keratins are typical intermediate filament proteins of the epithelium that exhibit highly specific expression patterns related to the epithelial type and stage of cellular differentiation. They are important for cytoplasmic stability and epithelial integrity and are involved in various intracellular signaling pathways. Several keratins are associated with enamel formation. However, information on their expression patterns during tooth development remains lacking. In this study, we analyzed the s

The epithelial-mesenchymal interactions are essential for the initiation and regulation of the development of teeth. Following the initiation of tooth development, numerous growth factors are secreted by the dental epithelium and mesenchyme that play critical roles in cellular differentiation. During tooth morphogenesis, the dental epithelial stem cells differentiate into several cell types, including inner enamel epithelial cells, which then differentiate into enamel matrix-secreting ameloblast

Enamel is formed by the repetitive secretion of a tooth-specific extracellular matrix and its decomposition. Calcification of the enamel matrix via hydroxyapatite (HAP) maturation requires pH cycling to be tightly regulated through the neutralization of protons released during HAP synthesis. We found that Gpr115, which responds to changes in extracellular pH, plays an important role in enamel formation. Gpr115-deficient mice show partial enamel hypomineralization, suggesting that other pH-respon

The coordination of dental cells is essential for tooth development. Various dental epithelial cell types are involved in tooth development, and each cell type plays a distinct role; however, the functional role of the outer enamel epithelium (OEE) remains unclear. We performed single-cell RNA-sequence (scRNA-seq) analysis of postnatal day (P) 7 incisors and embryonic day (E) 14 P1 molars of the mouse tooth germ to reveal the gene expression profile and role of OEE during tooth development. We i

An 84-year-old Japanese woman presented with left hemiplegia 8 months after completing chemotherapy for mantle cell lymphoma. Brain magnetic resonance imaging (MRI) revealed a hyperintense lesion extending from the right parietal lobe to the left parietal lobe. Compared with these MRI results, ¹⁸F-THK5351 PET revealed more extensive accumulation. A brain biopsy showed progressive multifocal leukoencephalopathy (PML). Immunohistochemistry and John Cunningham virus (JCV) DNA-polymerase

The process of sexual reproduction in eukaryotes starts when gametes from two different sexes encounter each other. <i>Paramecium</i>, a unicellular eukaryote, undergoes conjugation and uses a gametic nucleus to enter the sexual reproductive process. The molecules responsible for recognizing mating partners, hypothetically called mating-type substances, are still unclear. We have identified an O³-type mating substance polypeptide and its gene sequence using protein chemistry, molecula

These findings indicate that Dsc3 is essential for SI structural integrity and its signaling support to ameloblasts.

The process of sexual reproduction in eukaryotes starts when gametes from two different sexes encounter each other. Paramecium, a unicellular eukaryote, undergoes conjugation and uses a gametic nucleus to enter the sexual reproductive process. The molecules responsible for recognizing mating partners, hypothetically called mating-type substances, are still unclear. We have identified an O3-type mating substance polypeptide and its gene sequence using protein chemistry, molecular genetics, immuno