Immune Netw.  2022 Jun;22(3):e25. 10.4110/in.2022.22.e25.

IL-34 Aggravates Steroid-Induced Osteonecrosis of the Femoral Head via Promoting Osteoclast Differentiation

• Wang F
• Min HS
• Shan H
• Yin F
• Jiang C
• Zong Y
• Ma X
• Lin Y
• Zhou Z
• Yu X

• KMID: 2536252
• DOI: http://doi.org/10.4110/in.2022.22.e25

Abstract

IL-34 can promote osteoclast differentiation and activation, which may contribute to steroidinduced osteonecrosis of the femoral head (ONFH). Animal model was constructed in both BALB/c and IL-34 deficient mice to detect the relative expression of inflammation cytokines. Micro-CT was utilized to reveal the internal structure. In vitro differentiated osteoclast was induced by culturing bone marrow-derived macrophages with IL-34 conditioned medium or M-CSF. The relative expression of pro-inflammation cytokines, osteoclast marker genes, and relevant pathways molecules was detected with quantitative real-time RT-PCR, ELISA, and Western blot. Up-regulated IL-34 expression could be detected in the serum of ONFH patients and femoral heads of ONFH mice. IL-34 deficient mice showed the resistance to ONFH induction with the up-regulated trabecular number, trabecular thickness, bone value fraction, and down-regulated trabecular separation. On the other hand, inflammatory cytokines, such as TNF-α, IFN-γ, IL-6, IL-12, IL-2, and IL-17A, showed diminished expression in IL-34 deficient ONFH induced mice. IL-34 alone or works in coordination with M-CSF to promote osteoclastogenesis and activate ERK, STAT3, and non-canonical NF-κB pathways. These data demonstrate that IL-34 can promote the differentiation of osteoclast through ERK, STAT3, and non-canonical NF-κB pathways to aggravate steroid-induced ONFH, and IL-34 can be considered as a treatment target.

Keyword

IL34; Osteonecrosis; Osteoclast; M-CSF; Inflammation