High Mannose N-Glycans Promote Migration of Bone-Marrow-Derived Mesenchymal Stromal Cells

Abstract

For hundreds of indications, mesenchymal stromal cells (MSCs) have not achieved the expected therapeutic efficacy due to an inability of the cells to reach target tissues. We show that inducing high mannose N-glycans either chemically, using the mannosidase I inhibitor Kifunensine, or genetically, using an shRNA to silence the expression of mannosidase I A1 (MAN1A1), strongly increases the motility of MSCs. We show that treatment of MSCs with Kifunensine increases cell migration toward bone fracture sites after percutaneous injection, and toward lungs after intravenous injection. Mechanistically, high mannose N-glycans reduce the contact area of cells with its substrate. Silencing MAN1A1 also makes cells softer, suggesting that an increase of high mannose N-glycoforms may change the physical properties of the cell membrane. To determine if treatment with Kifunensine is feasible for future clinical studies, we used mass spectrometry to analyze the N-glycan profile of MSCs over time and demonstrate that the effect of Kifunensine is both transitory and at the expense of specific N-glycoforms, including fucosylations. Finally, we also investigated the effect of Kifunensine on cell proliferation, differentiation, and the secretion profile of MSCs. Our results support the notion of inducing high mannose N-glycans in MSCs in order to enhance their migration potential.

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

“…We recently showed that inducing high mannose N-glycans using Kifunensine also promotes migration of MSCs [13] and cancer cells [33]. Kifunensine also affected the secretion of angiogenic factors, osteogenesis, and adipogenesis in a very similar fashion to 3F-Neu5Ac [13].…”

“…We recently showed that inducing high mannose N-glycans using Kifunensine also promotes migration of MSCs [13] and cancer cells [33]. Kifunensine also affected the secretion of angiogenic factors, osteogenesis, and adipogenesis in a very similar fashion to 3F-Neu5Ac [13]. Since high-mannose N-glycans are not sialylated, perhaps both Kifunensine and 3F-Neu5Ac affect the cells through a common mechanism by reducing terminal sialic acid.…”

“…However, it has been shown that engineering glycosylations increases homing of MSCs to the bone marrow [15]. We have shown that inducing N-glycan core-fucosylations or high mannose N-glycans promote migration of MSCs [13,16]. Sialylations of N-glycans are known to play essential roles in the immune system and cancer [17,18].…”

“…Based on recent developments in the detection and modulation of N-linked glycosylations (N-glycans), we propose to harness these post-translational modifications to improve MSC's motility and survival. Some key advantages are that N-glycoforms can be modified without genetic modification and that these changes are only transient, depending on protein turnover [13].…”

Antitumor activity of a lectibody targeting cancer-associated high-mannose glycans

“…12 A recent publication assessing the impact of high-mannose glycans on bone-marrow-derived mesenchymal stromal cells has provided evidence that these glycans alter the physical and structural properties of the cells themselves, decreasing their size and increasing motility, which may in part explain the greater metastatic potential seen in other cell lines. 53 Given the growing body of evidence indicating the close association between the abundance of high-mannose glycans on cancer cells and increased cell migration and metastatic potential, it is of high clinical significance to uncover the cause and process leading to high-mannose overexpression in cancer and to scrutinize its functions in tumor microenvironments and metastasis. In this regard, AvFc may provide a valuable tool to probe and monitor high-mannose glycan accumulation on cell surface, thereby facilitating such investigations.…”