The laminin-411 protein is vital for the formation of the myelin membrane by oligodendrocytes, report researchers from Japan. Furthermore, the A4G47 peptide from the E8 region of laminin-411 was found to be the main active amino acid sequence that drives myelin formation. The research findings have the potential to transform current cell culture practices to study myelination and may enable the development of novel therapeutic agents to treat demyelinating diseases.
Myelin refers to the protective membrane that surrounds the axon—a long fiber-like projection of a nerve cell. The myelin sheath, mainly composed of lipids or other organic compounds, functions as an electrical insulator to ensure the rapid conduction of nerve signals. Any damage to the surrounding myelin membrane can disrupt the transmission of nerve signals and lead to a range of nerve disorders.
Oligodendrocytes (OLs) are the cells that form myelin sheaths around the nerve cells located within the brain and spinal cord. In recent years, several studies have investigated the development and differentiation of OLs and the underlying mechanisms involved in myelination or myelin formation. Reports suggest that laminin (LM), a large extracellular matrix (ECM) protein composed of multiple functional units, influences the myelination process of OLs. However, the specific protein units within LM that are responsible have not yet been discovered.
To identify and elucidate the role of LM protein on OL differentiation and myelination, a team of scientists led by Associate Professor Nobuharu Suzuki from the Department of Clinical Bioanalysis and Molecular Biology, Institute of Science Tokyo (Science Tokyo), Japan, have conducted a new study. Their research findings were made available online in the journal Glia on May 08, 2025, and will be published in Volume 73, Issue 8, in August 2025. Notably, an image from this study, published on June 23, 2025—created by Suzuki—was selected as the cover illustration for the 2025 Issue 8 of Glia, highlighting the scientific and visual impact of the research.
The present study, a collaborative research project involving researchers from Tokyo University of Pharmacy and Life Sciences and Osaka University, employed innovative molecular biology-based approaches and tools to reveal the functions of LM. Initially, the researchers examined the expression of LM in the brain and spinal cord tissue of mice at the age of around two weeks, where/when OLs actively form myelin sheaths around axons. They observed that LM alpha1 (α1), α2, and α4 chains were expressed in the perivascular basement membrane of the brain and spinal cord in the mice.
"Building on the findings from our previous studies, we focused on the expression and function of alpha chains of LM, namely α1, α2, α3, α4, and α5, in this study," says Suzuki, sharing further insights about the study. Thereafter, the scientists utilized artificially produced 'recombinant' proteins made from the α1, α2, and α4 chains of LM to identify the exact protein fragment that supports myelination by OLs. Results obtained via western blotting and immunocytochemistry—techniques to detect specific proteins within cells—indicated that LM-411 (artificial protein made from the α4 chain of LM) promoted the differentiation of OLs and the formation of the myelin membrane.
Finally, to identify the active region of the LM protein involved in myelination of OLs, the scientists focused on the E8 and E3 fragments. Their analyses revealed that the E8 fragment of the LM-411 protein was critical for myelin membrane formation. Contrastingly, the E3 fragments did not significantly influence the morphological differentiation of OLs. Furthermore, they identified A4G47 peptide—a short chain of amino acids derived from the LM-411E8 fragment—to be the main functional element that drives myelination by OLs.
Suzuki concludes by highlighting the potential applications of the present study, "LM-411, LM-411E8, and A4G47 are expected to serve as novel molecular tools for promoting myelination, with potential applications in the treatment of diseases such as multiple sclerosis, Alzheimer's disease, depression, and age-related cognitive decline."
Taken together, this study marks the first-ever discovery of a myelination-promoting peptide derived from an ECM protein and advances our understanding of myelin sheath formation.
