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Teeth are comprised of epithelial and mesenchymal cells, and regenerative teeth rely on the regeneration of both cell types. Transcription factors play a pivotal role in cell fate determination. In this study, we establish fluorescence models based on transcription factors to monitor and analyze dental epithelial cells. Using Pitx2-P2A-copGFP mice, we observe that Pitx2+ epithelial cells, when combined with E14.5 dental mesenchymal cells, are sufficient for the reconstitution of teeth. Induced-Pitx2+ cells, directly isolated from the embryoid body that employs the Pitx2-GFP embryonic stem cell line, exhibit the capacity to differentiate into ameloblasts and develop into teeth when combined with dental mesenchymal cells. The regenerated teeth exhibit a complete structure, including dental pulp, dentin, enamel, and periodontal ligaments. Subsequent exploration via RNA-seq reveals that induced-Pitx2+ cells exhibit enrichment in genes associated with FGF receptors and WNT ligands compared with induced-Pitx2- cells. Our results indicate that both primary Pitx2+ and induced Pitx2+ cells possess the capability to differentiate into enamel-secreting ameloblasts and grow into teeth when combined with dental mesenchymal cells. [ABSTRACT FROM AUTHOR]

Ecto‐mesenchymal cells of mammalian tooth germ develops from cranial neural crest cells. These cells are recognised as a promising source for tooth development and regeneration. Despite the high heterogeneity of the neural crest, the cellular landscape of in vitro cultured cranial neural crest cells (CNCCs) for odontogenesis remains unclear. In this study, we used large‐scale single‐cell RNA sequencing to analyse the cellular landscape of in vitro cultured mouse CNCCs for odontogenesis. We revealed distinct cell trajectories from primary cells to passage 5 and identified a rare Alx3+/Barx1+ sub‐population in primary CNCCs that differentiated into two odontogenic clusters characterised by the up‐regulation of Pax9/Bmp3 and Lhx6/Dmp1. We successfully induced whole tooth‐like structures containing enamel, dentin, and pulp under the mouse renal capsule using in vitro cultured cells from both cranial and trunk neural crests with induction rates of 26.7% and 22.1%, respectively. Importantly, we confirmed only cells sorted from odontogenic path can induce tooth‐like structures. Cell cycle and DNA replication genes were concomitantly upregulated in the cultured NCCs of the tooth induction groups. Our data provide valuable insights into the cell heterogeneity of in vitro cultured CNCCs and their potential as a source for tooth regeneration. [ABSTRACT FROM AUTHOR]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ydbio.2007.11.033 Byline: Jong-Min Lee (a), Jae-Young Kim (a)(b), Kyoung-Won Cho (a), Min-Jung Lee (a), Sung-Won Cho (a), Sungwook Kwak (a), Jinglei Cai (a), Han-Sung Jung (a) Keywords: Wnt11; Fgfr1b; Palatogenesis; Palatal growth; Palatal fusion; Cell proliferation; Apoptosis; z-VAD-fmk; Wnt11 siRNA Abstract: Various cellular and molecular events underlie the elevation and fusion of the developing palate that occurs during embryonic development. This includes convergent extension, where the medial edge epithelium is intercalated into the midline epithelial seam. We examined the expression patterns of Wnt11 and Fgfr1b - which are believed to be key factors in convergent extension - in mouse palate development. Wnt-11 overexpression and beads soaked in SU5402 (an Fgfr1 inhibitor) were employed in in vitro organ cultures. The results suggested that interactions between Wnt11 and Fgfr1b are important in modulating cellular events such as cell proliferation for growth and apoptosis for fusion. Moreover, the Wnt11 siRNA results showed that Wnt11-induced apoptosis was necessary for palatal fusion. In summary, Fgfr1b induces cell proliferation in the developing palate mesenchyme so that the palate grows and contacts each palatal shelf, with negative feedback of Fgfs triggered by excessive cell proliferation then inhibiting the expression of Fgfr1b and activating the expression of Wnt11 to fuse each palate by activating apoptosis. Author Affiliation: (a) Division in Anatomy and Developmental Biology, Department of Oral Biology, Research Center for Orofacial Hard Tissue Regeneration, Brain Korea 21 project, Oral Science Research Center, College of Dentistry, Yonsei Center of Biotechnology, Yonsei University, 134 Shinchon-Dong, Seodaemoon-Gu, Seoul, 120-752, Seoul, Republic of Korea (b) Department of Biochemistry, School of Dentistry, Kyungpook National University, Seoul, Republic of Korea Article History: Received 12 July 2007; Revised 20 November 2007; Accepted 28 November 2007

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ydbio.2007.01.002 Byline: Jinglei Cai, Sung-Won Cho, Jae-Young Kim, Min-Jung Lee, Yoon-Geun Cha, Han-Sung Jung Keywords: Tooth patterning; Tooth size; Cusp size; Cusp number; Tooth number; Reaction diffusion mechanism; Rodent Abstract: Mice and rats, two species of rodents, show some dental similarities such as tooth number and cusp number, and differences such as tooth size and cusp size. In this study, the tooth size, tooth number, cusp size and cusp number, which are four major factors of the tooth patterning, were investigated by the heterospecific recombinations of tissues from the molar tooth germs of mice and rats. Our results suggest that the dental epithelium and mesenchyme determine the cusp size and tooth size respectively and the cusp number is co-regulated by the tooth size and cusp size. It is also suggested that the mesenchymal cell number regulates not the tooth size but the tooth number. The relationships among these factors in tooth patterning including micropatterning (cusp size and cusp number) and macropatterning (tooth size and tooth number) were analyzed in a reaction diffusion mechanism. Key molecules determining the patterning of teeth remains to be elucidated for controlling the tooth size and cusp size of bioengineered tooth. Author Affiliation: Division in Anatomy and Developmental Biology, Department of Oral Biology, Research Center for Orofacial Hard Tissue Regeneration, Brain Korea 21 project, Oral Science Research Center, College of Dentistry, Yonsei Center of Biotechnology, Yonsei University, 134 Shinchon-Dong, Seodaemoon-Gu, Seoul 120-752, South Korea Article History: Received 21 July 2006; Revised 21 November 2006; Accepted 3 January 2007

The spatiotemporal relationships in high-resolution during odontogenesis remain poorly understood. We report a cell lineage and atlas of developing mouse teeth. We performed a large-scale (92,688 cells) single cell RNA sequencing, tracing the cell trajectories during odontogenesis from embryonic days 10.5 to 16.5. Combined with an assay for transposase-accessible chromatin with high-throughput sequencing, our results suggest that mesenchymal cells show the specific transcriptome profiles to distinguish the tooth types. Subsequently, we identified key gene regulatory networks in teeth and bone formation and uncovered spatiotemporal patterns of odontogenic mesenchymal cells. CD24 + and Plac8 + cells from the mesenchyme at the bell stage were distributed in the upper half and preodontoblast layer of the dental papilla, respectively, which could individually induce nonodontogenic epithelia to form tooth-like structures. Specifically, the Plac8 + tissue we discovered is the smallest piece with the most homogenous cells that could induce tooth regeneration to date. Our work reveals previously unknown heterogeneity and spatiotemporal patterns of tooth germs that may lead to tooth regeneration for regenerative dentistry., Competing Interests: Conflict of interest The authors declare that they have no conflict of interest., (Copyright © 2022 Science China Press. Published by Elsevier B.V. All rights reserved.)

Background: Hematopoiesis is a progressive process collectively controlled by an elaborate network of transcription factors (TFs). Among these TFs, GATA2 has been implicated to be critical for regulating multiple steps of hematopoiesis in mouse models. However, whether similar function of GATA2 is conserved in human hematopoiesis, especially during early embryonic development stage, is largely unknown., Results: To examine the role of GATA2 in human background, we generated homozygous GATA2 knockout human embryonic stem cells (GATA2 (-/-) hESCs) and analyzed their blood differentiation potential. Our results demonstrated that GATA2 (-/-) hESCs displayed attenuated generation of CD34(+)CD43(+) hematopoietic progenitor cells (HPCs), due to the impairment of endothelial to hematopoietic transition (EHT). Interestingly, GATA2 (-/-) hESCs retained the potential to generate erythroblasts and macrophages, but never granulocytes. We further identified that SPI1 downregulation was partially responsible for the defects of GATA2 (-/-) hESCs in generation of CD34(+)CD43(+) HPCs and granulocytes. Furthermore, we found that GATA2 (-/-) hESCs restored the granulocyte potential in the presence of Notch signaling., Conclusion: Our findings revealed the essential roles of GATA2 in EHT and granulocyte development through regulating SPI1, and uncovered a role of Notch signaling in granulocyte generation during hematopoiesis modeled by human ESCs.