The expression patterns of β1,4 galactosyltransferase I and V mRNAs, and Galβ1-4GlcNAc group in rat gastrocnemius muscles post sciatic nerve injury

Abstract

Glycosylation is one of the most important post-translational modifications. It is clear that the single step of beta1,4-galactosylation is performed by a family of beta1,4-galactosyltransferases (beta1,4-GalTs), and that each member of this family may play a distinct role in different tissues and cells. beta1,4-GalT I and V are involved in the biosynthesis of N-linked oligosaccharides and play roles in sciatic nerve regeneration after sciatic nerve injury. In the present study, the expression of beta1,4-galactosyltransferase (beta1,4-GalT) I, V mRNAs and Galbeta1-4GlcNAc group were examined in rat gastrocnemius muscles after sciatic nerve crush and transection. Real time PCR revealed that beta1,4-GalT I and V mRNAs expressed at a high level in normal gastrocnemius muscles and decreased gradually from 6 h, reached the lowest level at 2 weeks, then restored gradually to relatively normal level at 4 weeks after sciatic nerve crush. In contrast, in sciatic nerve transection model, beta1,4-GalT I and V mRNAs decreased gradually from 6 h, and remained on a low level at 4 weeks in gastrocnemius muscles after sciatic nerve transection. In situ hybridization indicated that beta1,4-GalT I and V mRNAs localized in numerous myocytes and muscle satellite cells under normal conditions and at 4 weeks after sciatic nerve crush, and in a few muscle satellite cells at 4 weeks after sciatic nerve transection. Furthermore, lectin blotting showed that the expression level of the Galbeta1-4GlcNAc group decreased from 6 h, reached the lowest level at 2 weeks, and restored to relatively normal level at 4 weeks after sciatic nerve crush. RCA-I lectin histochemistry demonstrated that Galbeta1-4GlcNAc group localized in numerous membranes of myocytes and muscle satellite cells in normal and at 4 weeks after sciatic nerve crush, and in a few muscle satellite cells at 2 and 4 weeks after sciatic nerve transection. These results indicated that the expressions of beta1,4-GalT I, V mRNAs and Galbeta1-4GlcNAc group were involved in the process of denervation and reinnervation, which suggests that beta1,4-GalT I, V mRNAs and Galbeta1-4GlcNAc group may play an important role in the muscle regeneration.

B4GALT family mediates the multidrug resistance of human leukemia cells by regulating the hedgehog pathway and the expression of p-glycoprotein and multidrug resistance-associated protein 1

“…7 As a house keeping enzyme, β 1, 4-Gal-T1 is thought to be the key enzyme to have important roles in many biological events, including morphogenesis, mammalian fertilization, brain development, cellular adhesion, and so on 8, 9, 10, 11. Abnormal expression of β 1, 4-Gal-T has been shown to be implicated in a number of diseases 12, 13, 14, 15 , and levels of cell surface β 1, 4-Gal-T could be influenced by many factors. Literatures show that estrogen and arachidonic acid promote proliferation and cell adhesion of human breast cancer cells by inducing β 1, 4-Gal-T1 expression.1 3, 16 In embryonic stem cells, β 1, 4-Gal-T1 expression is regulated by a novel ubiquitin-conjugating enzyme accounting for intercellular adhesion and embryonic development.…”

Expression of the hyaluronan receptor LYVE‐1 is not restricted to the lymphatic vasculature; LYVE‐1 is also expressed on embryonic blood vessels

“…Sciatic nerve injury leads to a variety of changes in muscle morphology and biochemistry, including inflammation 2, 3. The immune system is known to play a specific role in certain muscle disorders,4, 5 as well as after denervation.…”

FYN‐dependent muscle–immune interaction after sciatic nerve injury

“…However, it appears that different target cell populations can play different roles during different phases of the post‐injury response. Because immediate treatment is most effective for structural and functional recovery2, 3 we focused on the initial events taking place in the denervated muscle following sciatic injury.…”

“…Sciatic nerve injury leads to a variety of changes in muscle morphology and biochemistry, including inflammation. 2,3 The immune system is known to play a specific role in certain muscle disorders, 4,5 as well as after denervation. Following sciatic nerve injury, immunological changes in the gastrocne-mius muscle include invasion by T cells and increased expression of immune regulators such as major histocompatibility complex (MHC) and B7 molecules.…”