The Role of the Immune Microenvironment on Osteoblast Differentiation

Osteoblasts, derived from mesenchymal stem cells (MSCs) in the bone marrow, are responsible for bone formation. Osteoblast differentiation is orchestrated by a spectrum of biological signals, with immune-derived components serving as indispensable regulators in this network. Dysfunctional osteoblast differentiation underlies bone-related pathologies such as osteoarthritis, rheumatoid arthritis, and osteoporosis, where immune dysregulation drives inflammatory cascades that disrupt the osteoblast-osteoclast equilibrium. This bidirectional crosstalk has propelled the emergence of osteoimmunology as a pivotal discipline. By analyzing immune cells and cytokines in the immune microenvironment, we synthesize evidence on their roles in regulating osteoblast differentiation, with focus on inflammatory bone disorders, particularly in osteoarthritis. Thus, bone growth, development, and healing are intrinsically coupled with the dynamics of the immune microenvironment, which contributes to subchondral bone sclerosis and disease progression in osteoarthritis. Therefore, targeting immune-osteoblast crosstalk offers therapeutic potential for bone pathologies. This review consolidates recent advances in understanding how the immune microenvironment impacts osteoblast differentiation, aiming to provide novel insights for clinical strategies targeting bone repair and disease mitigation.