Mussaendoside O, a N-triterpene cycloartane saponin, attenuates RANKL-induced osteoclastogenesis and inhibits lipopolysaccharide-induced bone loss

Minju Gal; Okwha Kim; Phuong Thao Tran; Le Thanh Huong; Nguyen Xuan Nhiem; Phan Van Kiem; Nguyen Hai Dang; Jeong-Hyung Lee

doi:10.1016/j.phymed.2022.154378

Mussaendoside O, a N-triterpene cycloartane saponin, attenuates RANKL-induced osteoclastogenesis and inhibits lipopolysaccharide-induced bone loss

Phytomedicine. 2022 Oct:105:154378. doi: 10.1016/j.phymed.2022.154378. Epub 2022 Aug 3.

Authors

Minju Gal¹, Okwha Kim², Phuong Thao Tran¹, Le Thanh Huong³, Nguyen Xuan Nhiem⁴, Phan Van Kiem⁴, Nguyen Hai Dang⁵, Jeong-Hyung Lee⁶

Affiliations

¹ Department of Biochemistry, College of Natural Sciences, Kangwon National University, Chuncheon, Gangwon-Do 24341, Republic of Korea.
² Kangwon Institute of Inclusive Technology, Kangwon National University, Chuncheon, Gangwon-Do 24341, Republic of Korea.
³ University of Science and Technology of Hanoi, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam.
⁴ Institute of Marine Biochemistry, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam.
⁵ University of Science and Technology of Hanoi, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam. Electronic address: nguyen-hai.dang@usth.edu.vn.
⁶ Department of Biochemistry, College of Natural Sciences, Kangwon National University, Chuncheon, Gangwon-Do 24341, Republic of Korea; Kangwon Institute of Inclusive Technology, Kangwon National University, Chuncheon, Gangwon-Do 24341, Republic of Korea. Electronic address: jhlee36@kangwon.ac.kr.

PMID: 35961265
DOI: 10.1016/j.phymed.2022.154378

Abstract

Background: Elevated activity of osteoclasts (OCs) is linked to osteolytic bone diseases, such as osteoporosis and rheumatoid arthritis. Developing natural anti-osteoclastogenic compounds with greater efficacy and fewer adverse effects is crucial for preventing or treating osteolytic bone diseases. N-triterpene cycloartane saponins (NTCSs) are rarely found in nature, and their inhibitory effects on OC differentiation in vitro and in vivo have not yet been explored.

Purpose: This study was aimed to investigate the effect of mussaendoside O, an NTCS isolated from Mussaenda pubescens, on RANKL-induced OC differentiation and its underlying mechanism in vitro, and lipopolysaccharide (LPS)-induced bone resorption in a mouse model.

Methods: The content of mussaendoside O in methanol extract of M. pubescens was determined by HPLC. The inhibitory effects of mussaendoside O on RANKL-induced OC formation were assessed using TRAP staining, western blotting, immunofluorescence staining, and real-time qPCR. Meanwhile, the effects of mussaendoside O on LPS-induced inflammatory responses were assessed using a Griess reagent and qPCR. The effects of mussaendoside O on LPS-induced bone resorption in a mouse model were evaluated using micro-CT and immunohistochemical staining.

Results: Mussaendoside O inhibited RANKL-induced TRAP-positive multinucleated OC formation in a concentration-dependent manner without affecting cell viability. However, mussaendoside O did not inhibit LPS-induced mRNA expression of COX-2, iNOS, and TNF-α. Mice orally administrated with mussaendoside O exhibited significant protection from LPS-induced bone resorption and OC formation. At the molecular level, mussaendoside O suppressed RANKL-activated phosphorylation of p38 MAPK and JNK, as well as c-Fos expression. In addition, mussaendoside O suppressed RANKL-induced NFATc1 activation and the expression of its target genes, including OSCAR, DC-STAMP, CtsK, and TRAP.

Conclusion: Mussaendoside O attenuates OC differentiation in vitro and LPS-induced bone resorption in a mouse model by inhibiting the RANKL-activated c-Fos/NFATc1 signaling pathways. Therefore, mussaendoside O may be a valuable lead compound for preventing or treating of osteolytic bone diseases.

Keywords: Bone loss; Mussaendoside O; N-triterpene cycloartane saponin; NFATc1; Osteoclastogenesis; c-Fos.

MeSH terms

Animals
Bone Resorption*
Cell Differentiation
Lipopolysaccharides
Mice
NFATC Transcription Factors
Osteoclasts
Osteogenesis
RANK Ligand
Saponins*
Triterpenes*

Substances

Lipopolysaccharides
NFATC Transcription Factors
RANK Ligand
Saponins
Triterpenes
mussaendoside O
cycloartane