Echinococcus multilocularis drives the polarization of macrophages by regulating the RhoA-MAPK signaling pathway and thus affects liver fibrosis

Abstract

Echinococcus multilocularis is a small parasite that causes alveolar echinococcosis. It primarily induces liver disorder, such as liver fibrosis and even liver cancer, which severely endangers human lives. This study aims to explore the efficacy of Echinococcus multilocularis soluble antigen in preventing and alleviating alveolar echinococcosis-induced liver fibrosis and determine the underlying mechanism. We first identified the optimal dose and time of Echinococcus multilocularis soluble antigen. The protein levels of key genes in the RhoA-MAPK signaling pathway were remarkably upregulated in RAW264.7 and Ana-1 cells induced with 80 μg/mL Echinococcus multilocularis soluble antigen for 8 h. Interestingly, the upregulated expression levels were remarkably reversed by the RhoA, JNK, ERK, or p38 inhibitor, confirming the significance of the RhoA-MAPK signaling pathway. In addition, the relative contents of M2 polarization markers IL-10 and Arg-1 in macrophages induced with 80 μg/mL Echinococcus multilocularis soluble antigen for 8 h increased, whereas those of M1 polarization markers IL-12 and NOS-2 decreased. Mouse hepatic stellate cells were the key components of the hepatocellular carcinoma tumor microenvironment. Hepatic stellate cells were activated by Echinococcus multilocularis soluble antigen and transformed into the morphology of myofibroblasts in response to liver disorders. By detecting the marker of myofibroblast formation, RhoA inhibitor remarkably reduced the positive expression of α-SMA in mouse hepatic stellate cells induced with Echinococcus multilocularis soluble antigen. Therefore, Echinococcus multilocularis soluble antigen remarkably activated the RhoA-MAPK pathways in macrophages, further inducing the polarization of macrophages and ultimately causing liver fibrosis. Hypothesis: We hypothesize that infection with Echinococcus multilocularis activates the RhoA-MAPK signaling pathway and subsequently induces macrophage polarization to promote hepatic stellate cells activation leading to liver fibrosis. Aims: To investigate the mechanism by which soluble antigen of Echinococcus multilocularis affects liver fibrosis through the RhoA-MAPK pathway driving polarization of macrophages. Goals: To identify new pathways of intervention and drug targets for the regulation of macrophage polarity phenotype switching and the attenuation or inhibition of the development and treatment of liver fibrosis caused by Echinococcus multilocularis infection.

Endogenous IL-33 Accelerates Metacestode Growth during Late-Stage Alveolar Echinococcosis

“…CD206 + macrophages have been described to promote angiogenesis and produce chemokines supporting tumor growth ( 29 , 30 ). AE was shown to be associated with periparasitic accumulation of monocyte-derived M1 macrophages during the early phase of infection, which acquire a M2 phenotype (CD206 + ) during the chronic stage of infection ( 31 , 32 ). These macrophages are considered to favor parasite growth because they secrete the anti-inflammatory cytokine IL-10 and the fibrogenic cytokine TGF-β1, which has a dual role: slowing the parasite growth on one hand, and having immunosuppressive properties on the other ( 32 – 34 ).…”

“…AE was shown to be associated with periparasitic accumulation of monocyte-derived M1 macrophages during the early phase of infection, which acquire a M2 phenotype (CD206 + ) during the chronic stage of infection ( 31 , 32 ). These macrophages are considered to favor parasite growth because they secrete the anti-inflammatory cytokine IL-10 and the fibrogenic cytokine TGF-β1, which has a dual role: slowing the parasite growth on one hand, and having immunosuppressive properties on the other ( 32 – 34 ). Interestingly, we observed in IL-33 −/− mice both a decrease in CD206 + tolerogenic macrophages and lower concentrations of IL-10 and TGF-β1 in the peritoneal cavity, compared to those in WT mice.…”

Wnt family member 1 (Wnt1) overexpression-induced M2 polarization of microglia alleviates inflammation-sensitized neonatal brain injuries

“…Microglial cells are macrophages derived from the mesoderm and are of two types, M1 and M2, after activation [ 33 ]. M2 microglia polarization is associated with numerous diseases, including cancers, inflammation, and fibrosis diseases [ 30 , 31 , 34 ]. Activated M2 microglia are involved in a series of immune responses, such as phagocytosis of apoptotic and damaged cells [ 35 ], inflammatory responses, and [ 36 ] tissue repair [ 37 ], which play a neuroprotective role.…”

“…Immunofluorescence staining was performed as previous described [ 31 ]. BV2 cells were cultured in Dulbecco’s modified Eagle’s medium supplemented with 10% fetal bovine serum and then infected with GFP-tagged LC3 lentivirus (GeneChem, Shanghai, China) according to the manufacturer’s protocol.…”

Advances in the pharmacological treatment of hepatic alveolar echinococcosis: From laboratory to clinic

“…MAPK signaling pathway is crucial for parasitic infection ( Zhao et al, 2019 ). Shigui Chong et al found that soluble antigen of Echinococcus multilocularis induces macrophage polarization after alveolar echinococcosis infection through RhoA MAPK signal pathway ( Chong et al, 2022 ). Emmpk1, a host extracellular signal regulated kinase (ERK), could activate parasitic MAPK cascade as it could be phosphorylated by multilocular Echinococcus cysts in vitro ( Hemphill et al, 2002 ; Spiliotis et al, 2006 ).…”