The periosteum plays a critical role in bone repair and is significantly influenced by the surrounding immune microenvironment. In this study, we employed 10× single-cell RNA sequencing to create a detailed cellular atlas of the swine cranial periosteum, highlighting the cellular dynamics and interactions essential for cranial bone injury repair. We noted that such injuries lead to an increase in M2 macrophages, which are key in modulating the periosteum’s immune response and driving the bone regeneration process. These macrophages actively recruit periosteal stromal cells (PSCs) by secreting Neuregulin 1 (NRG1), a crucial factor in initiating bone regeneration. This recruitment process emphasizes the critical role of PSCs in effective bone repair, positioning them as primary targets for therapeutic interventions. Our results indicate that enhancing the interaction between M2 macrophages and PSCs could significantly improve the outcomes of treatments aimed at cranial bone repair and regeneration.

Tooth germ development is a precisely orchestrated process dependent on integrated cellular interactions and molecular signals, yet its regulatory mechanisms remain incompletely defined. Here, we constructed a high-resolution cellular atlas of miniature pig tooth germs using 10× single-cell RNA sequencing to investigate the molecular mechanisms underlying tooth mineralization. By leveraging cellular heterogeneity and dynamic gene expression trajectories in epithelial and mesenchymal populations, we identified microfibril-associated protein 5 (MFAP5) as a previously unrecognized regulator of the odontogenic program. Functional assays demonstrate that MFAP5, an extracellular matrix component, is indispensable for mesenchymal differentiation and matrix mineralization in vitro. Mechanistically, MFAP5 engages Integrin alpha-5 (ITGA5) to activate Extracellular Signal-Regulated Kinase/Mitogen-Activated Protein Kinase (ERK/MAPK) signaling in odontoblast-lineage cells, thereby promoting odontoblast differentiation and dentin deposition. Collectively, our single-cell–resolved analyses uncovered a MFAP5–ITGA5–ERK/MAPK signaling axis that operates in a cell-state–specific manner during tooth germ mineralization, providing new mechanistic insights into odontogenic differentiation and a potential molecular basis for dental tissue regeneration strategies.

Epigenetic regulation provides new insights into the mechanisms of osteogenic differentiation and identifies potential targets for treating bone-related diseases. However, the specific regulatory networks and mechanisms involved still need further investigation. In this study, we identify PRMT7 as a novel epigenetic regulator of mesenchymal stem cells (MSCs) osteogenic commitment. Conditional knockout of Prmt7 in mice reveals a significant impairment in osteogenesis and bone regeneration, specifically in females, affecting both femurs and mandibles, with no noticeable effect in males. Mechanistically, PRMT7 modulates MSCs osteogenic differentiation by activating PTEN. Specifically, PRMT7 enhances PTEN transcription by increasing H3R2me1 levels at the PTEN promoter. Additionally, PRMT7 interacts with the PTEN protein and stabilizes nuclear PTEN, revealing an unprecedented pathway. Notably, overexpression of PTEN alleviates the osteogenic deficits observed in Prmt7-deficient mice. This research establishes PRMT7 as a potential therapeutic target for promoting bone formation/regeneration and offers novel molecular insights into the PRMT7–PTEN regulatory axis, underscoring its significance in bone biology and regenerative medicine.

The periosteum plays a central role in skeletal regeneration by serving as a reservoir of skeletal stem cells and a dynamic regenerative niche. However, in vitro models that faithfully preserve its cellular complexity, long‐term stability, and functional capacity remain limited, restricting mechanistic studies and translational applications. Here, we establish a long‐term expandable periosteal organoid system that can be stably propagated for over 20 passages while preserving cellular heterogeneity, multilineage differentiation potential, and genomic integrity. Single‐cell transcriptomic analysis reveals sustained maintenance of core periosteal lineages and regenerative signaling programs over extended culture. Functionally, these organoids reconstruct a niche‐like microenvironment that supports hematopoietic stem cell (HSC) maintenance, preserves stem cell fitness, and attenuates aging‐associated functional decline under prolonged ex vivo conditions. Upon transplantation, periosteal organoids robustly engraft and actively participate in tissue repair, promoting vascularized bone formation and reconstruction of marrow‐like structures across multiple defect models. Mechanistically, we identify ZFP575 as a 3D niche‐dependent regulator required for maintaining in vivo osteogenic competence. Together, our findings establish periosteal organoids as a physiologically relevant and functionally competent regenerative platform, providing a versatile system for modeling skeletal repair and stem cell‐niche interactions.