Glycosylation as a tracer of off-target Cre-lox activation in development.

The Cre-lox system is one of the most widely used methods for lineage-specific and inducible genome editing in vivo. However, incomplete penetrance and off-target effects due to transient promoter expression in a stem or pluripotent precursor cell can be problematic and difficult to detect, especially if the target gene is not normally present in the fully differentiated but off-target cells. Yet, the loss of the target gene through the transient expression of Cre may impact the differentiation of those cells by virtue of transient expression in a precursor population.

IgG sialylation occurs via the FcRn-mediated recycling pathway in endothelial cells.

IgG is a key mediator of immune responses throughout the human body, and the structure of the conserved glycan on the Fc region has been identified as a key inflammatory switch regulating its downstream effects. In particular, the absence of terminal sialic acid has been shown to increase the affinity of IgG for activating Fc receptors, cascading the inflammatory response in a variety of diseases and conditions. Previously, we have shown that IgG sialylation is mediated by B cell-extrinsic processes.

Acute and chronic lung inflammation drives changes in epithelial glycans.

Introduction: Asthma is the most common chronic inflammatory disease and it is characterized by leukocyte infiltration and tissue remodeling, with the latter generally referring to collagen deposition and epithelial hyperplasia. Changes in hyaluronin production have also been demonstrated, while mutations in fucosyltransferases reportedly limit asthmatic inflammation.

Methods: Given the importance of glycans in cellular communication and to better characterize tissue glycosylation changes associated with asthma, we performed a comparative glycan analysis of normal and inflamed lungs from a selection of murine asthma models.

Divergent Golgi trafficking limits B cell-mediated IgG sialylation.

The degree of α2,6-linked sialylation on IgG glycans is associated with a variety of inflammatory conditions and is thought to drive IgG anti-inflammatory activity. Previous findings revealed that ablation of β-galactoside α2,6-sialyltransferase 1 (ST6Gal1) in B cells failed to alter IgG sialylation in vivo, yet resulted in the loss of B cell surface α2,6 sialylation, suggesting divergent pathways for IgG and cell surface glycoprotein glycosylation and trafficking. Employing both B cell hybridomas and ex vivo murine B cells, we discovered that IgG was poorly sialylated by ST6Gal1 and highly core fucosylated by α1,6-fucosyltransferase 8 (Fut8) in cell culture.

Antigen presenting cell response to polysaccharide A is characterized by the generation of anti-inflammatory macrophages.

Polysaccharide A (PSA) is the immunodominant capsular carbohydrate from the gram negative commensal microbe Bacteroides fragilis that has shown remarkable potency in ameliorating many rodent models of inflammatory disease by eliciting downstream suppressive CD4+ T cells. PSA is composed of a zwitterionic repeating unit that allows it to be processed by antigen presenting cells (APCs) and presented by MHCII in a glycosylation-dependent manner. While previous work has uncovered much about the interactions between MHCII and PSA, as well as the downstream T cell response, little is known about how PSA affects the phenotype of MHCII+ APCs, including macrophages.