Echinococcus granulosus sensu lato promotes osteoclast differentiation through DUSP4-MAPK signaling in osseous echinococcosis

haohao sun ¹ yaqing liu ¹ yiping huang ¹ kangjun xiong ¹ zhendong zhang ¹ weishan wang ¹ yi dai ¹ jing li ¹ qi li ¹ sibo wang ^2* Chenhui Shi ^1*

• ¹ First Affiliated Hospital, School of Medicine, Shihezi University, Shihezi, Xinjiang Uyghur Region, China
• ² Xi'an Honghui Hospital, Xi'an, Shaanxi Province, China

： Cystic echinococcosis (CE), a zoonotic disease with global distribution, particularly affects grazing areas such as northwest China. Osseous echinococcosis accounts for approximately 4% of all CE, but its insidious onset and lack of early diagnostic tools contribute to delayed detection and a high disability rate. Despite its significant clinical impact, the pathogenesis of bone destruction caused by the tapeworm Echinococcus granulosus (E. granulosus) has not been thoroughly investigated. Bone destruction is largely attributed to the overactivation of osteoclasts, which are multinucleated giant cells responsible for bone resorption and closely associated with abnormal bone metabolism. This study investigated the effects of E. granulosus larvae -2 protoscoleces (PSC)on osteoclast differentiation and function. In vitro experiments revealed that PSC significantly enhanced the nuclear factor-kappa B ligand (RANKL)-induced formation of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated osteoclasts. Transcriptome sequencing showed that PSC intervention led to the significant downregulation of dual-specificity protein phosphatase 4 (DUSP4), a dephosphorylated enzyme commonly expressed in eukaryotic cells. Overexpression of DUSP4 exerted notable negative regulatory effects on osteoclast formation by suppressing the expression of osteoclast differentiation marker genes at both the mRNA and protein levels. These effects were mediated through the inhibition of RANKL-induced activation of mitogen-activated protein kinase (MAPK) signaling pathway, including ERK, JNK, and p38. In a mouse model of osseous echinococcosis, DUSP4 overexpression via lentiviral transduction significantly attenuated bone destruction and osteoclast formation. These findings suggest that PSC promotes RANKL-induced differentiation of bone marrow macrophages into osteoclasts by downregulating DUSP4, which otherwise inhibits osteoclast activation and bone loss through suppression of the MAPK signaling pathway. This study highlights the potential of targeting DUSP4 and MAPK signaling as therapeutic strategies for managing bone destruction in osseous echinococcosis and similar osteoclast-mediated bone diseases.Cystic echinococcosis (CE) is a zoonotic disease caused by the larval stage of the fine-grained tapeworm Echinococcus granulosus (E. granulosus). Following accidental ingestion of E. granulosus eggs through contaminated food/water, the eggs hatch into oncospheres within the digestive tract. These larvae subsequently penetrate the intestinal wall, enter the bloodstream,