BACKGROUND/PURPOSE It remains unclear what role curcumin plays in the autophagy of osteoclast precursors (OCPs) during osteoclastogenesis, since some researchers found that curcumin has the ability to inhibit osteoclastogenesis. While others have considered it as an autophagy activator. This study aimed to determine the effect of curcumin-regulated autophagy on osteoclastogenesis. RESULTS The results revealed that direct administration of curcumin enhanced the OCP autophagy response in bone marrow-derived macrophages (BMMs). Curcumin could also abate RANKL's stimulatory effect on OCP autophagy and osteoclastogenesis. Autophagic suppression related to pharmacological inhibitors or gene silencing could further enhance the inhibitory effect of curcumin on osteoclastogenesis. As expected, curcumin ameliorated ovariectomy (OVX)-induced bone loss and its effect could be promoted by an autophagy inhibitor (chloroquine). CONCLUSIONS In conclusion, curcumin can directly enhance the autophagic activity of OCPs, which inhibits its anti-osteoclastogeneic effects. Autophagy inhibition-based drugs are expected to enhance curcumin's efficacy in treating osteoporosis.

中文翻译：

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姜黄素激活的自噬在其抗破骨细胞作用中起着负面作用。

背景/目的姜黄素在破骨细胞形成过程中在破骨细胞前体（OCP）自噬中起什么作用尚不清楚，因为一些研究人员发现姜黄素具有抑制破骨细胞形成的能力。而其他人则认为它是自噬激活剂。这项研究旨在确定姜黄素调节的自噬对破骨细胞形成的影响。结果结果表明，直接给予姜黄素可增强骨髓源性巨噬细胞（BMM）的OCP自噬反应。姜黄素还可以减轻RANKL对OCP自噬和破骨细胞生成的刺激作用。与药理学抑制剂或基因沉默相关的自噬抑制作用可进一步增强姜黄素对破骨细胞形成的抑制作用。不出所料 姜黄素可改善卵巢切除术（OVX）引起的骨质流失，其作用可通过自噬抑制剂（氯喹）来促进。结论总之，姜黄素可直接增强OCP的自噬活性，从而抑制其抗成骨作用。基于自噬抑制的药物有望增强姜黄素治疗骨质疏松症的功效。