Mesenchymal Stromal Cells Regulate Sialylations of N-Glycans, Affecting Cell Migration and Survival

Abstract

N-Glycosylations are an important post-translational modification of proteins that can significantly impact cell function. Terminal sialic acid in hybrid or complex N-glycans has been shown to be relevant in various types of cancer, but its role in non-malignant cells remains poorly understood. We have previously shown that the motility of human bone marrow derived mesenchymal stromal cells (MSCs) can be modified by altering N-glycoforms. The goal of this study was to determine the role of sialylated N-glycans in MSCs. Here, we show that IFN-gamma or exposure to culture media low in fetal bovine serum (FBS) increases sialylated N-glycans, while PDGF-BB reduces them. These stimuli alter mRNA levels of sialyltransferases such as ST3Gal1, ST6Gal1, or ST3Gal4, suggesting that sialylation of N-glycans is regulated by transcriptional control of sialyltransferases. We next show that 2,4,7,8,9-pentaacetyl-3Fax-Neu5Ac-CO2Me (3F-Neu5Ac) effectively inhibits sialylations in MSCs. Supplementation with 3F-Neu5Ac increases adhesion and migration of MSCs, as assessed by both videomicroscopy and wound/scratch assays. Interestingly, pre-treatment with 3F-Neu5Ac also increases the survival of MSCs in an in vitro ischemia model. We also show that pre-treatment or continuous treatment with 3F-Neu5Ac inhibits both osteogenic and adipogenic differentiation of MSCs. Finally, secretion of key trophic factors by MSCs is variably affected upon exposure to 3F-Neu5Ac. Altogether, our experiments suggest that sialylation of N-glycans is tightly regulated in response to environmental cues and that glycoengineering MSCs to reduce sialylated N-glycans could be beneficial to increase both cell migration and survival, which may positively impact the therapeutic potential of the cells.

Cytokines in the Immune Microenvironment Change the Glycosylation of IgG by Regulating Intracellular Glycosyltransferases

“…The regulatory effects of cytokines on glycosylation enzymes are examined in limited studies and are poorly understood and controversial. For example, IFN-γ increases sialylated N-glycan structures due to upregulated mRNA levels of sialyltransferases (ST6GAL1) in human bone marrow-derived mesenchymal stromal cells (MSCs) to influence migration and survival ( 52 ). However, another study reported that IFN-γ decreased the expression of ST6GAL1 in LPS-induced B cell cultures ( 44 ).…”

Cutaneous Lymphocyte Antigen Is a Potential Therapeutic Target in Cutaneous T-Cell Lymphoma

“…ST3Gal-4 involvement in cancer cell migration processes was previously described. However, except for stem/stromal cell biology, its role in cell survival remains not wellestablished (Guerrero et al, 2020;Templeton et al, 2021). Our results suggest that targeting ST3Gal-4 sialyl transferase in the context of CTCL could represent another strategy to induce tumor cell death.…”

“…Our results suggest that targeting ST3Gal-4 sialyl transferase in the context of CTCL could represent another strategy to induce tumor cell death. However, alternative therapeutic drugs are necessary because current inhibitors of sialyltransferase are not ST3Gal-4 specific and may have therefore important side effects (Templeton et al, 2021). These unexpected effects include an increase in tumor cell survival as observed in human multiple myeloma cells (Natoni et al, 2020).…”

The Applications of Metabolic Glycoengineering

“…Both Ac 5 ManNTProp and Ac 5 ManNTBut, which display thiol groups on the cell surface, were found to suppress adipogenic differentiation in hADSCs, but they did not interfere with differentiation to a glial lineage ( Du et al, 2021 ). Moreover, both osteogenic and adipogenic differentiation were inhibited, when MSCs were pre- or continuous treated with 3F-Neu5Ac ( Templeton et al, 2021 ).…”

“…The cells enhanced trophic factor release by optimizing stiffness of the polymer coating, which reduced the required number of cells through augmenting the efficacy of each NPC. On the other hand, supplementation with 3F-Neu5Ac was found to improve adhesion and elevate the rate of migration of MSCs, thereby promoting their survival in an in vitro ischemia model ( Templeton et al, 2021 ). In summary, MGE can effectively modulate cell biological behaviors ( Table 1 ).…”