Aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that plays a crucial role in bone remodeling through altering the interplay between bone-forming osteoblasts and bone-resorbing osteoclasts. While effects of AhR signaling in osteoblasts are well understood, the role and mechanism of AhR signaling in regulating osteoclastogenesis is not widely understood. AhR, when binding with exogenous ligands (environmental pollutants such as polycylic aryl hydrocarbon (PAH), dioxins) or endogenous ligand indoxyl-sulfate (IS), has dual functions that are mediated by the nature of the binding ligand, binding time, and specific pathways of distinct ligands. In this review, AhR is discussed with a focus on (i) the role of AhR in osteoclast differentiation and function and (ii) the mechanisms of AhR signaling in inhibiting or promoting osteoclastogenesis. These findings facilitate an understanding of the role of AhR in the functional regulation of osteoclasts and in osteoclast-induced bone destructive conditions such as rheumatoid arthritis and cancer.

中文翻译：

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芳基烃受体（AhR）在破骨细胞分化和功能中的作用

芳烃受体（AhR）是一种配体激活的转录因子，通过改变成骨成骨细胞和吸收骨破骨细胞之间的相互作用，在骨重塑中起关键作用。虽然AhR信号在成骨细胞中的作用已广为人知，但AhR信号在调节破骨细胞形成中的作用和机制尚未广泛了解。当与外源性配体（环境污染物，例如多环芳基烃（PAH），二恶英）或内源性配体吲哚硫酸盐（IS）结合时，AhR具有双重功能，这由结合配体的性质，结合时间和特异性决定不同配体的途径。在这篇评论中 对AhR的讨论主要集中在（i）AhR在破骨细胞分化和功能中的作用以及（ii）AhR信号传导在抑制或促进破骨细胞形成中的机制。这些发现促进了对AhR在破骨细胞功能调节和破骨细胞诱导的骨破坏性疾病如类风湿关节炎和癌症中的作用的理解。