Three novel low molecular weight (LMW) polypeptide fragments of a proteolipid
protein human PLP / DM20 are designated PIRP-M, PIRP-L and PIRP-J, and are growth factors for oligodendrocytes with anti-apoptotic activity. They are encoded by mRNA from an IRES. Fusion polypeptides of such a LMW polypeptide,
DNA encoding the LMW polypeptide and fusion polypeptide, expression vectors comprising such
DNA, and cells expressing such polypeptides, or pharmaceutical compositions thereof, are useful for stimulating
neural stem cell differentiation, maturation along the oligodendrocytic pathway and proliferation of oligodendrocytes or precursors. These compositions can protect oligodendrocytes (and nonneural cells) from apoptotic death. Thus, the present composition is used to treat a
disease or condition in which such differentiation, maturation and proliferation or inhibition of
cell death, including
remyelination or stimulation of oligodendroglia or Schwann cells, is desirable. Disorders include
multiple sclerosis, trauma with Parkinson's-like symptoms, hypoxic ischerriia and
spinal cord trauma.