KSGal6ST Is Essential for the 6-Sulfation of Galactose within Keratan Sulfate in Early Postnatal Brain

Abstract

SummaryKeratan sulfate (KS) comprises repeating disaccharides of galactose (Gal) and N-acetylglucosamine (GlcNAc). Residues of Gal and GlcNAc in KS are potentially modified with sulfate at their C-6 positions. The 5D4 monoclonal antibody recognizes KS structures containing Gal and GlcNAc, both 6-sulfated, and has been used most extensively to evaluate KS expression in mammalian brains. We previously showed that GlcNAc6ST1 is an enzyme responsible for the synthesis of the 5D4 epitope in developing brain and in the adult brain, where it is induced after injury. It has been unclear which sulfotransferase is responsible for Gal-6-sulfation within the 5D4 KS epitope in developing brains. We produced mice deficient in KSGal6ST, a Gal-6-sulfotransferase. Western blotting and immunoprecipitation revealed that all 5D4-immunoreactivity to proteins, including phosphacan, were abolished in KSGal6ST-deficient postnatal brains. Likewise, the 5D4 epitope, expressed primarily in the cortical marginal zone and subplate and dorsal thalamus, was eliminated in KSGal6ST-deficient mice. Disaccharide analysis showed the loss of Gal-6-sulfate in KS of the KSGal6ST-deficient brains. Transfection studies revealed that GlcNAc6ST1 and KSGal6ST cooperated in the expression of the 5D4 KS epitope in HeLa cells. These results indicate that KSGal6ST is essential for C-6 sulfation of Gal within KS in early postnatal brains. (J Histochem Cytochem 62:145-156, 2014)

Keratan sulfate (KS)‐proteoglycans and neuronal regulation in health and disease: the importance of KS‐glycodynamics and interactive capability with neuroregulatory ligands

“…Phosphacan is present in early postnatal brains in mice, the 5D4 epitope on KS requires the action of the sulfotransferase GlcNAc6ST1 (Hoshino et al . ), and this mitigates AD pathology (Zhang et al . ).…”

“GAG-ing with the neuron”: The role of glycosaminoglycan patterning in the central nervous system

“…It is expressed in different cell types in the CNS, including activated microglia and macrophages, as well as oligodendrocyte precursor cells (Dou and Levine, 1994;. Phosphacan, a highly expressed PG in the CNS containing CS and/or KS side chains, exists as a transmembrane receptor phosphatase and as a cleaved molecule that can be released to the ECM (Hoshino et al, 2014;Margolis et al, 1996).The levels of phosphacan and phosphacan-KS increase significantly in late embryonic period and well into postnatal development (Maeda et al, 1995). A form of phosphacan bearing CS and KS has been shown in rat CNS postnatally (Butler et al, 2004).…”

“…GlcNAc6ST1 is induced in the brain and spinal cord of adult mice after injury, and the loss of KS facilitates axonal regeneration (Hoshino et al, 2014;Zhang et al, 2006a). On the other hand, phosphacan inhibits cell adhesion to tenascin (Grumet et al, 1994) and promotes neurite extension of cortical neurons (Maeda et al, 1995).…”

Keratan sulfate: An up-to-date review

“…[26], the authors have reported the use of an anti-KS 5D4 antibody against the Gal6S-GlcNAc6S epitope of KS. In a recent work of Hoshino and co-authors, the other sulfotransferase KSGal6ST, responsible to place sulfation at the 6C-position of Gal units in KS, was also examined in terms to its specificity with 5D4 reactivity in developing brains [37]. By examining brains of GlcNAc6ST1-or KSGal6ST-deficient mice at postnatal periods, the authors were able to observe that the 5D4 epitope, formed primarily in the cortical marginal zone, subplate and dorsal thalamus, was completely eliminated in any cases.…”

“…By examining brains of GlcNAc6ST1-or KSGal6ST-deficient mice at postnatal periods, the authors were able to observe that the 5D4 epitope, formed primarily in the cortical marginal zone, subplate and dorsal thalamus, was completely eliminated in any cases. Hence, a cooperative expression of both sulfotransferases is required for the proper neural development in mice, as seen by the immunoreactivity of the 5D4 KS epitope [37].…”