Mir140 is a microRNA that plays significant roles in various biological processes. It is involved in cartilage development [3,4,6]. In skeletal progenitor cells and chondrocytes, it regulates aspects of cellular function, thus contributing to skeletal development [4]. Dysregulation of Mir140 can lead to skeletal dysplasias, highlighting its importance in normal skeletal formation [4,5].

In obesity-related bone deterioration, conditional knockout of BMM miR-140 in mice showed resistance to obesity-induced bone deterioration. This indicates that Mir140 in bone marrow macrophages (BMMs) promotes obesity-induced bone deterioration, likely by regulating the differentiation of skeletal stem/progenitor cells (SSPCs) towards adipocytes as it has the function of promoting adipogenesis [1]. In knee osteoarthritis, exosomes derived from human urine-derived stem cells overexpressing miR-140-5p alleviated the condition in a rat model. This was achieved through down-regulation of VEGFA, enhancing chondrocyte proliferation, migration, and extracellular matrix secretion, as well as cartilage regeneration and subchondral bone remodeling [2].

In conclusion, Mir140 is crucial for cartilage development and skeletal formation. Its dysregulation can lead to skeletal dysplasias. In the context of obesity-related bone deterioration and knee osteoarthritis, findings from gene-knockout or over-expression models in mice have revealed its role in disease progression and potential as a therapeutic target. Understanding Mir140's function contributes to the development of treatments for these bone-related diseases.