Skeletal and cartilage diseases are common diseases with societal and economic impacts. The most common skeletal diseases include osteoporosis, femoral head necrosis, lumbar muscle degeneration, and bone tumors and common cartilage disorders include intervertebral disc degeneration and disc herniation. These diseases are characterized by dysfunctions of bone- or cartilage-derived stem or progenitor cells, and aberrant activation of signaling pathways, e.g., NF-κB, SIRT1, and other related signaling pathways.

The development, growth, and regeneration of bone, cartilage, and intervertebral disc rely on the resident stem or progenitor cells, such as bone marrow-derived mesenchymal stem cells, cartilage stem, or progenitor cells, and intervertebral disc stem cells including nucleus pulposus, annulus fibrosis, and notochord cell progenitor cells. Functional deficiency of stem or of progenitor cells is considered a hallmark of various skeletal-related diseases. However, the origin, tempo-spatial distribution, heterogeneity, and functions of stem and progenitor cells in bone/cartilage diseases remain unclear. Advances in single-cell sequencing techniques for individual omics and multi-omics profiling in single cells have made it possible to uncover the pathogenesis of skeletal-related diseases. Large-scale high-throughput genomic analysis speeds up the identification of new drug targets and the development of specific targeted therapies for bone diseases and disorders.

The aim of this Special Issue is to collate research that elucidates the origin, tempo-spatial distribution, heterogeneity, and functions of stem and progenitor cells derived from bone or cartilage. We also welcome original or review articles related to novel therapeutic strategies for bone/cartilage diseases, such as new drug discovery, stem cells therapy, etc.

Potential topics include but are not limited to the following:

• Identification of potential resident stem and progenitor cells in intervertebral discs, including nucleus pulposus, annulus fibrosis, hyaline cartilaginous endplates, and disc perichondrium
• Mechanisms of the signaling pathways and cascade response of stem and progenitor cells in bone and cartilage diseases
• Characterization of new candidate markers for resident stem and progenitor cells in bone and cartilage diseases
• Discovery of novel therapeutic methods targeting resident stem and progenitor cells in bone and cartilaginous cells, including drug and stem cells therapy
• stablishment of high-throughput virtual screening approaches, i.e. molecular docking analysis and molecular dynamics simulation, to assess and verify drug properties in treating bone and cartilage diseases