Myelin Synthesis Pathway (via Methylcobalamin) (None)

The myelin synthesis pathway via methylcobalamin (MeCbl) refers to the biological processes by which methylcobalamin, an active form of vitamin B12, supports and promotes the formation and regeneration of myelin sheaths in the nervous system. MeCbl acts as a coenzyme for methionine synthase, facilitating the conversion of homocysteine to methionine, which is crucial for generating S-adenosylmethionine (SAM), a universal methyl group donor involved in DNA, protein, and lipid methylation. It supports phospholipid synthesis, promotes Schwann cell differentiation and increases expression of myelin basic protein (MBP), enhancing lecithin synthesis and accelerating peripheral nerve regeneration after injury. Methylcobalamin supplementation is used therapeutically in various neuropathies. Deficiency leads to impaired methionine synthase activity, resulting in defective DNA/lipid/protein methylation cycles—ultimately causing demyelination seen in subacute combined degeneration.

Methylcobalamin acts as a cofactor for methionine synthase, promoting methionine and SAM synthesis, which are crucial for phospholipid/myelin production and nerve regeneration. It also modulates Erk1/2 and Akt signaling pathways to enhance myelination.