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Background Development of placenta and differentiation of trophoblast is a hallmark event for successful pregnancy. Trophoblast stem (TS) cells proliferate and differentiate into TS-like cytotrophoblasts (CTBs), further formulate the differentiated subtypes, syncytiotrophoblasts (STBs) and invasive extravillous tropholoblasts (EVTs). Defective differentiation of TS-like CTBs is associated with severe gestational diseases. Protein glycosylation is an essential form of posttranslational modification. However, glycosylation-related mechanism controlling TS-like CTBs differentiation remains unknown. This study aims to investigate the function of high-mannose type glycans and ALG3 on TS-like CTBs differentiation. Furthermore, the mechanism of high-mannose and ITGAM during TS-like CTBs differentiation were explored.Methods Employing lectin microarray, the glycosylation expression traits were compared in the villi of miscarriage patients and healthy women. The expression of high-mannose and ALG3 were investigated by immunoblotting and immunofluorescence assays. The glycosylation proteins were screened by pull down and LC-MS/MS detection. Signaling pathway were screened by the human phosphokinase antibody array. The differentiation of TS-like CTBs were measured by immunoblotting and immunofluorescence assays.Results Lectin microarray results revealed that increased level of high-mannose type glycans on the TS-like CTBs of miscarriage patients compared with normal pregnancy women. Meantime, ALG3 levels increased in TS-like CTBs of miscarriage patients. Upregulating high-mannose type glycans by ALG3 hampered TS-like CTBs differentiated into STBs and EVTs, and arrested TS-like CTBs in the property stage. Furthermore, high level of high-mannose type glycans on ITGAM inhibited the binding of ITGAM and Fn, inactivating the p-STAT1 signaling pathway, further inhibiting TS-like CTBs differentiation potential.Conclusions These findings reveal that high-mannose type glycans, especially on ITGAM, hampered binding of ITGAM and Fn, which leads to the impaired TS-like CTBs differentiation by p-STAT1 signaling pathway. The present study provides novel insight into the function and mechanism of α1,3-linked high-mannose type glycans in TS-like CTBs differentiation in human placenta, which can also be used as a glycol molecular target for the treatment of miscarriage.

Peritoneal metastasis is the main cause of poor prognoses and high mortality in ovarian cancer patients. Abnormal protein glycosylation modification is associated with cancer malignancy. Elevated α1,3-mannosyltransferase 3 (ALG3), which catalyzes the α1,3-mannosylation of glycoproteins, has been found in some malignant tumors. However, the pathological significance of ALG3 and its regulatory mechanism in ovarian cancer metastasis is unclear. The results showed that the level of ALG3/α1,3-mannosylation was higher in human ovarian cancer tissues compared with normal ovarian tissues, as measured by Lectin chip, Western blot and Lectin blot analyses, as well as ovarian tissue microarray analysis. ALG3 was also correlated with the poor prognosis of ovarian cancer patients, according to survival analysis. The downregulation of ALG3 decreased the proliferation, stemness and peritoneal metastasis of ovarian cancer cells. The increase in urokinase plasminogen activator receptor (uPAR) α1,3-mannosylation catalyzed by ALG3 enhanced urokinase plasminogen activator (uPA)/uPAR activation and the interaction of uPAR with a disintegrin and metalloproteinase 8 (ADAM8), which promoted ovarian cancer peritoneal metastasis via the ADAM8/Ras/ERK pathway. Furthermore, decreased ALG3 suppressed ascites formation and the peritoneal metastasis of ovarian cancer cells in mice. This study highlights ALG3 as a potential diagnostic biomarker and prospective therapeutic target for ovarian cancer.