Objective To investigate the effects of Echinococcus multilocularis on the phenotypic transformations of glucose metabolism, polarization types and inflammatory responses in macrophages, so as to provide insights into elucidation of echinococcosis pathogenesis. Methods Bone marrow cells were isolated from C57BL/6J mice at ages of 6 to 8 weeks, and induced into bone marrow-derived macrophages (BMDMs) with mouse macrophage colony-stimulating factor (M-CSF), which served as controls (BMDMs-M0). BMDMs-M0 induced M2 macrophages by interleukin-4 for 24 hours served as the IL-4 induction group, and BMDMs-M0 co-cultured with 2.4 ng/mL E. multilocularis cystic fluid (CF) served as the BMDM-CF co-culture group, while BMDMs-M0 co-cultured with E. multilocularis protoscolex (PSC) at a ratio of 500:1 served as the BMDM-PSC co-culture group. The types of polarization of BMDMs co-cultured with E. multilocularis CF and PSC were analyzed using flow cytometry, and the expression of macrophage markers, inflammatory factors, and glucose metabolism-related enzymes was quantified using fluorescent quantitative real-time PCR (qPCR) and Western blotting assays. Results There were significant differences among the four groups in terms of Arginase-1 (Arg1) (F = 1 457.00, P < 0.000 1), macrophages-derived C-C motif chemokine 22 (Ccl22) (F = 22 203.00, P < 0.000 1), resistin-like α (Retnla) (F = 151.90, P < 0.000 1), inducible nitric oxide synthase (iNOS) (F = 107.80, P < 0.001), hexokinase (HK) (F = 9 389.00, P < 0.000 1), pyruvate kinase (PK) (F = 641.40, P < 0.001), phosphofructokinase 1 (PFK1) (F = 43.97, P < 0.01), glucokinase (GK) (F = 432.50, P < 0.000 1), pyruvate dehydrogenase kinases1 (PDK1) (F = 737.30, P < 0.000 1), lactic dehydrogenase (LDH) (F = 3 632.00, P < 0.000 1), glucose transporter 1 (GLUT1) (F = 532.40, P < 0.000 1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) (F = 460.00, P < 0.000 1), citrate synthase (CS) (F = 5 642.00, P < 0.01), glycogen synthase1 (GYS1) (F = 273.30, P < 0.000 1), IL-6 (F = 1 823.00, P < 0.000 1), IL-10 (F = 291.70, P < 0.000 1), IL-1β (F = 986.60, P < 0.000 1), and tumor necrosis factor (TNF)-α (F = 334.80, P < 0.000 1) and transforming growth factor (TGF)-β mRNA expression (F = 163.30, P < 0.001). The proportion of M2 macrophages was significantly higher than that of M1 macrophages in the BMDM-PSC co-culture group [(22.87% ±1.48%) vs. (1.70% ±0.17%); t = 24.61, P < 0.001], and the proportion of M2 macrophages was significantly higher than that of M1 macrophages in the BMDM-CF co-culture group [(20.07% ±0.64%) vs. (1.93% ±0.25%); t = 45.73, P < 0.001]. The mRNA expression of M2 macrophages markers Arg1, Ccl22 and Retnla was significantly higher in the BMDM-CF and BMDM-PSC co-culture groups than in the control group (all P values < 0.01), and no significant difference was seen in the mRNA expression of the M1 macrophage marker iNOS among the three groups (P > 0.05), while qPCR assay quantified higher mRNA expression of key glycolytic enzymes HK, PK and PFK, as well as inflammatory factors IL-10, IL-1β, TNF-α and TGF-β in the BMDM-CF and BMDM-PSC co-culture groups than in the control group (all P values < 0.01). Western blotting assay determined higher HK, PK and PFK protein expression in the BMDM-PSC co-culture group than in the control group (all P values < 0.05), and qPCR quantified higher GLUT1, GAPDH and IL-6 mRNA expression in the BMDM-CF co-culture group than in the control group (all P values < 0.05), while higher HK, PK and PFK protein and mRNA expression (all P values < 0.01), as well as lower IL-6 and TNF-α and higher TGF-β mRNA expression (both P values < 0.05) was detected in the IL-4 induction group than in the control group. Glycolytic stress test showed no significant difference in the extracellular acidification rate (ECAR) of mouse BMDM among the control group, IL-4 induction group and BMDM-PSC co-culture group (F = 124.4, P < 0.05), and a higher ECAR was seen in the BMDM-PSC co-culture group and a lower ECAR was found in the IL-4 induction group than in the control group (both P values < 0.05). Conclusions Treatment of E. multilocularis CF or PSC mainly causes polarization of BMDM into M2 macrophages, and phenotypic transformation of glucose metabolism into high-energy and high-glycolytic metabolism, and affects inflammatory responses in BMDM.

Objective To investigate the effect of exosomes derived from Echinococcus multilocularis on macrophage polarization after treatment for different durations and concentrations. Methods A total of 60 BALB/c mice were used for modeling, among which 4 mice were selected to observe the growth of abdominal lesions on 7.0T MRI. The mice for modeling were dissected, and the protoscoleces was taken from the abdominal lesion and cultured in vitro ; ultracentrifugation was used to extract the exosomes from the supernatant, and transmission electron microscopy and Western blotting were used for the characterization of exosomes. The macrophages without exosome treatment were established as control group, and the macrophages co-cultured with different concentrations of exosomes derived from Echinococcus multilocularis were established as experimental group (10 μg/mL group and 50 μg/mL group) and were cultured for 48 and 72 hours. The morphological changes of macrophages were observed under a microscope, and flow cytometry and ELISA were used to observe polarization state. A one-way analysis of variance was used for comparison of normally distributed continuous data between multiple groups, and the least significant difference t -test was used for further comparison between two groups. Results The results of 7.0T MRI showed the formation of diffuse lesions with different sizes in the abdominal cavity of mice, and the exosomes derived from Echinococcus multilocularis were approximately 100 nm in diameter and were cup-shaped or saucer-shaped, with the positive expression of the surface markers CD9, TSG101, and CD63. After co-culture, most of the cells in the experimental group were elongated with an irregular and polygonal shape. Flow cytometry showed that after 48 hours of co-culture, the positive rates of CD16/32, CD206, and CD369 in the control group were 99.53%±0.06%, 90.27%±0.21%, and 2.40%±0.20%, respectively; compared with the control group, except that the 10 μg/mL exosome group had a significant reduction in the positive rate of CD369 (0.80%±0.00%) ( P < 0.05), all the other groups had a significant increase in the positive rates of CD16/32, CD206, and CD369 (all P < 0.000 1); after 72 hours of co-culture, the positive rates of CD16/32, CD206, and CD369 in the control group were 99.67%±0.06%, 85.47%±0.55%, and 6.60%±0.20%, respectively, and compared with the control group, the experimental group had significant increases in the positive rates of CD16/32, CD206, and CD369 (all P < 0.05). ELISA showed that after 48 hours of co-culture, the levels of IL-6 and TNFα in the control group were 58.53±15.52 pg/mL and 320.70±5.30 pg/mL, respectively, and when the exosome concentration was 50 μg/mL, the level of IL-6 in the experimental group was 98.81±15.55 pg/mL, which was higher than that in the control group ( P < 0.05); after 72 hours of co-culture, the levels of IL-6 and TNFα in the control group were 76.22±9.68 pg/mL and 323.90±87.37 pg/mL, respectively, and when the exosome concentration was 10 μg/mL, the level of TNFα was 164.20±14.17 pg/mL, which was significantly lower than that in the control group ( P < 0.05); when the exosome concentration was 50 μg/mL, the level of IL-6 was 99.52±8.35 pg/mL, which was significantly higher than that in the control group ( P < 0.05). Conclusion Exosomes derived from Echinococcus multilocularis can regulate macrophage polarization and induce M2-like polarization of macrophages after co-culture at a concentration of 10 μg /mL for 72 hours, and further studies are needed to clarify the specific method.