ANGPTL2 deletion inhibits osteoclast generation by modulating NF-κB/MAPKs/Cyclin pathways

Journal Article · Sat Sep 15 04:00:00 EDT 2018 · Biochemical and Biophysical Research Communications

DOI:https://doi.org/10.1016/J.BBRC.2018.07.065· OSTI ID:23103677

Li, Wei-Ming; Han, Chen-Long ^[1]; Liu, Chen ^[2]; Xing, Hai-Yang ^[3]; Ding, De-Chen ^[4]

---

1. The First Affiliated Hospital of Harbin Medical University, Harbin, 150001 (China)
2. The Second Affiliated Hospital of Harbin Medical University, Harbin, 150001 (China)
3. Cang Zhou Hospital of Integrated Traditional Chinese and Western Medicine of Hebei Province, CangZhou, 061001 (China)
4. Yishui People's Hospital, Yishui, 276400 (China)

Highlights: • ANGPTL2 is associated with the osteoclast development. • Inhibition of ANGPTL2 reduces the proliferation of osteoclast precursors. • ANGPTL2 deficiency alleviates ovariectomy (OVX)-induced bone loss. Osteoclasts are multinucleated cells essential for bone-resorption. Successful repair of bone defciencies still remains a great challenge worldwide. The signaling factor angiopoietin-like protein 2 (ANGPTL2), one of eight ANGPTL proteins, functions in maintenance of tissue homeostasis partly through regulating inflammation. In the study, ANGPTL2 expression was promoted during osteoclast development and that suppressing ANGPTL2 alleviated osteoclast production regulated by macrophage colony-stimulating factor (M-CSF) and receptor activator of NF-κB ligand (RANKL). The results suggested that ANGPTL2 knockdown inhibited M-CSF-caused proliferation of osteoclast precursor cells. Further, ANGPTL2 silence reduced nuclear factor of activated T cell c 1 (NFATC1) and NFATC4 expressions in M-CSF-treated cells, along with decreased Runx2, OPN and Colla1. Moreover, silencing ANGPTL2 down-regulated M-CSF-promoted expressions of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, and chemoattractant protein-1 (CCL-2). Consistently, ANGPTL2 knockdown reduced M-CSF-enhanced activation of IKKα, IκBα and nuclear factor κB (NF-κB) and mitogen-activated protein kinases (MAPKs) (p38 MAPK, ERK1/2 MAPK and JNK MAPK). Additionally, knockdown of ANGPTL2 inhibited the induction of Cyclin D1, Cyclin D2 and Cyclin E1 due to M-CSF exposure. In vivo, we confirmed that ANGPTL2 knockout (KO) mice were protected against osteoporosis induced by ovariectomy (OVX), as proved by the improved bone loss and bone mineral density (BMD). Decreased expression of NFATCs was also observed in OVX-induced mice in the absence of ANGPTL2. Elevated release of pro-inflammatory cytokines was abrogated by ANGPTL2 knockout in femoral heads of mice with OVX operation, accompanied with a significant reduction of phosphorylated NF-κB and MAPKs signaling pathways. And down-regulated expression of Cyclin D1, Cyclin D2 and Cyclin E1 was observed in OVX-operated mice with ANGPTL2 knockout. Therefore, our study indicated that ANGPTL2 played an essential role in osteoclast generation through regulating the proliferation and inflammation of osteoclast lineage cells, providing new insights into the therapeutic strategy to alleviate bone loss.

• OSTI ID: 23103677
• Journal Information: Biochemical and Biophysical Research Communications, Journal Name: Biochemical and Biophysical Research Communications Journal Issue: 3 Vol. 503; ISSN BBRCA9; ISSN 0006-291X
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
BONE MINERAL DENSITY
INFLAMMATION
LYMPHOKINES
MACROPHAGES
MICE
OSTEOPOROSIS
PHOSPHOTRANSFERASES