Efficient reprogramming of human fibroblasts using RNA reprogramming with DAPT and iDOT1L under normoxia conditions

The next generation of regenerative dentistry: From tooth development biology to periodontal tissue, dental pulp, and whole tooth reconstruction in the clinical setting

In modern dentistry, prosthetic approaches such as implants and dentures have been developed as symptomatic solutions for tooth loss. However, the complete regeneration of teeth and periodontal tissue, an ultimate aspiration of humanity, remains unachieved. Recent advancements in fundamental scientific technologies, including single-cell RNA sequencing and spatial transcriptomics, have significantly advanced our molecular understanding of tooth development, paving the way toward achieving this goal. This review summarizes the fundamental processes of tooth development in humans and mice, recent findings from basic research, and current clinical applications in dental regenerative medicine, including periodontal, alveolar bone, and dental pulp regeneration using cellular approaches. Building on accumulated scientific knowledge, the complete regeneration of teeth and periodontal tissues may be achievable in the near future. We discuss the potential of emerging approaches, such as organoids derived from pluripotent stem cells and xenotransplantation using genetically modified animals, to transform dental medicine. These innovative concepts and integrated technologies hold the promise of enabling the regeneration of fully functional teeth and periodontal tissues.

A passage-free, simplified, and scalable novel method for iPSC generation in three-dimensional culture

Induced pluripotent stem cells (iPSCs) have immense potential for use in disease modeling, etiological studies, and drug discovery. However, the current workflow for iPSC generation and maintenance poses challenges particularly during the establishment phase when specialized skills are required. Although three-dimensional culture systems offer scalability for maintaining established iPSCs, the enzymatic dissociation step is complex and time-consuming. In this study, a novel approach was developed to address these challenges by enabling iPSC generation, maintenance, and differentiation without the need for two-dimensional culture or enzymatic dissociation. This streamlined method offers a more convenient workflow, reduces variability and labor for technicians, and opens up avenues for advancements in iPSC research and broader applications.

Induction of periodontal ligament-derived mesenchymal stromal cell-like cells from human induced pluripotent stem cells

Introduction

Periodontal disease is a common oral infection which affects the tooth-supportive tissues directly. Considering the limitation of present regenerative treatments for severe periodontal cases, cytotherapies have been gradually introduced. Human periodontal ligament-derived mesenchymal stromal cells (hPDLMSCs), while identified as one of the promising cell sources for periodontal regenerative therapy, still hold some problems in the clinical application especially their limited life span. To solve the problems, human induced pluripotent stem cells (hiPSCs) are taken into consideration as a robust supply for hPDLMSCs.

Methods

The induction of hPDLMSCs was performed based on the generation of neural crest-like cells (NCLCs) from hiPSCs. Fibronectin and laminin were tested as coating materials for NCLCs differentiation when following previous protocol, and the characteristics of induced cells were identified by flow cytometry and RT-qPCR for evaluating the induction efficiency. Subsequently, selected dental ectoderm signaling-related cytokines were applied for hPDLMSCs induction for 14 days, and dental mesenchyme-related genes, dental follicle-related genes and hPDL-related genes were tested by RT-qPCR for the evaluation of differentiation.

Results

Compared to the 58% in laminin-coated condition, fibronectin-coated condition had a higher induction efficiency of CD271high cells as 86% after 8-day induction, while the mesenchymal potential of induced NCLCs was similar between two coating materials.It was shown that the gene expressions of dental mesenchyme, dental follicles and hPDL cells were significantly enhanced with the stimulation of the combination with fibroblast growth factor 8b (FGF8b), FGF2, and bone morphogenetic protein 4 (BMP4).

Conclusion

FN coating was more effective in NCLCs induction, and the FGF8b+FGF2+BMP4 growth factor cocktail was effective in hPDLMSC-like cell generation. These findings underscored the likely regenerative potential of hiPSCs as an applicable and promising curative strategy for periodontal diseases.