RGD-containing peptides inhibit the synthesis of myelin-like membrane by cultured oligodendrocytes.

Abstract

Abstract.A synthetic peptide derived from the fibronectin cell-binding domain, GRGDSP, inhibits the adhesion of rat oligodendrocytes to a number of substrates. However, while GRGDSP inhibited the adhesion of cells in a short term adhesion assay, the presence of the peptide did not prevent cells from adhering and thriving in longer term culture. The morphological characteristics of individual cells cultured with 0.1 mg/ml GRGDSP were similar to untreated cultures; small rounded cell bodies radiating numerous fine processes. Peptide-treated cultures were inhibited in their ability to produce myelin specific components. The characteristic developmental peak in sulfolipid synthesis which occurs both in vivo and in vitro was completely inhibited when cells were cultured with GRGDSP. In addition, the synthesis of myelin basic protein was inhibited. Ultrastructurally, cells treated with GRGDSP showed a greatly reduced number of multilamellar myelin-like membrane figures than cells grown without peptide or those grown with GRADSP. Cultured oligodendrocytes did not become sensitive to inhibition of sulfolipid synthesis by GRGDSP until a period immediately preceding the peak in sulfolipid biosynthesis. The effects of pretreatment with peptide for 5 d before this time were completely reversible. Pretreatment which extended into the time of peak myelin synthesis resulted in permanent impairment in the cell's ability to synthesize sulfolipid. The oligodendrocyte's ability to synthesize a myelin-like membrane in culture is, in part, inherent since it occurs in the absence of neurons. The present results indicate that myelin membrane production is also subject to external control since it appears that occupancy of an RGD-dependent cell surface receptor during a critical period of in vitro development is required for the oligodendrocyte to produce myelin-like membrane.

Reversible inhibition of oligodendrocyte progenitor differentiation by a monoclonal antibody against surface galactolipids.

“…In favor ofthis model, immature myoblast differentiation has been reversibly inhibited by an antibody against the extracellular matrix protein integrin (38); 04 antibody greatly enhanced OL aggregation, leading to the stimulation ofmyelinogenesis (19); cell-substrate adhesion is critical for the development of lamb OLs in culture (39,40); the adhesion glycoprotein laminin and the platelet glycoprotein thrombospondin (41) have distinct functional domains for sulfatide binding, suggesting a possible role for sulfatide in cellular adhesion; myelinogenic expression can be blocked by a tripeptide sequence common to a number of cell binding molecules (42). In the latter case, the inhibition they observed appeared later in myelinogenesis than reported here for RmAb and was irreversible when the tripeptide was presented to the cells during optimal myelinogenic expression.…”

O2A progenitor cells transplanted into the neonatal rat brain develop into oligodendrocytes but not astrocytes.

“…The medium was decanted and the cells were pelleted by centrifugation. The pellet was resuspended in culture medium, sequentially filtered through 25 …”

Axonal Proteins Involved in Myelination: Characterization of a Collagen-Like Protein

“…[ 1993] have shown that the survival of developing oligodendroglia was promoted by neuronal cell surface or ECM-bound neuronal signaling molecules. Though little is understood about the influence of ECM on CNS myelination, an arginine-glycine-aspartic acid containing ECM component has been implicated in oligodendrocyte adhesion and myelin synthesis in vitro [Cardwell and Rome, 1988a;1988b;Malek-Hcdayat and Rome, 1994], Here we report the isolation and partial characteriza tion of the 140-and 120-kD G21.3-immunoreactive pro teins in CNS and PNS.…”

“…Pre vious studies have demonstrated that elaboration of the Schwann cell basal lamina is a necessary step in subse quent normal Schwann cell development, which includes ensheathment and myelination of axons Carey and Bunge, 1981;Moya et al, 1980]. A matrix requirement has yet to be determined foroligodendroglia, while there is evidence supporting the importance of ECM in myelinogenesis in vitro [Lubetzki-Korn et al, 1983;Ovadia et al, 1984;Cardwell and Rome, 1988b;Rome et al, 1990;Agrcsti ct al., 1991;Malek-Hcdayat and Rome, 1994], Barres ct al. [ 1993] have shown that the survival of developing oligodendroglia was promoted by neuronal cell surface or ECM-bound neuronal signaling molecules.…”