Toxicity of ricin and volkensin, two ribosome-inactivating proteins, to microglia, astrocyte, and neuron cultures

Abstract

Ricin and volkensin, two potent toxins belonging to the family of ribosome‐ inactivating proteins (RIPs), have been largely exploited in recent years in in vivo experiments of neuronal degeneration consequent to suicide transport or immunolesioning. We have determined both the toxicity of, and the inhibition of, protein synthesis by ricin and volkensin in in vitro cultures enriched in microglial cells, astrocytes, or neurons. In microglial cultures, 50% of toxicity (estimated by LDH released from dead cells) after 24 h exposure to RIPs was obtained with volkensin at 2.2×10−12 M concentration and 50% of protein synthesis inhibition at 2×10−14 M concentration. Both values were higher by about one order of magnitude in astrocyte‐enriched cultures. Toxicity of, and inhibition of, protein synthesis by, ricin were lower for both cell types by about 1 order of magnitude as compared to volkensin. Cerebellar granule neurons in culture survived remarkably well to 24 h exposure to ricin or volkensin, although their protein synthesis was effectively inhibited by the two toxins with a potency similar to that found for astrocytes. These results demonstrate that glial cells, in particular microglia, are very sensitive to RIPs toxicity and should, therefore, be a primary target of these toxins when injected in vivo. Thus, the damage observed after in vivo experiments could be partly related to diffusion of toxic substances from early‐affected glial cells. GLIA 20:203‐209, 1997. © 1997 Wiley‐Liss, Inc.

Astrocytic Toll-Like Receptor 3 Is Associated with Ischemic Preconditioning- Induced Protection against Brain Ischemia in Rodents

“…The pellet was resuspended and cultured in flasks at a concentration of 2×10 6 cells/mL. On day 19 of culture, the flasks were shaken again to exclude microglial contamination [35], and astrocytes remaining in the flasks were harvested. The pellet was resuspended to a concentration of 1–2×10 5 cells/mL with culture medium containing 20% fetal bovine serum.…”

Insulin-like Growth Factor-1-mediated Neuroprotection against Oxidative Stress Is Associated with Activation of Nuclear Factor κB

“…Cell Cultures-Primary cultures of rat cerebellar granule neurons were prepared from 8-day-old Sprague-Dawley (Charles River, Sulzfeld, Germany) rat pups, as described previously (26). Neurons dissociated from cerebellar were plated at different densities (see below) on plastic dishes coated with poly-L-lysine (10 g/ml) and grown in basal modified Eagle's medium containing 10% heat-inactivated fetal calf serum, 25 mM KCl, 2 mM glutamine, and 100 g/ml gentamicin.…”

Interaction of volkensin with HeLa cells: binding, uptake, intracellular localization, degradation and exocytosis

“…It also has the highest cytotoxicity, inhibiting protein synthesis by HeLa cells with an IC 50 (concentration giving 50 % inhibition) of 0.3 pM, approximately 1/3 that of ricin. Volkensin is also more toxic than ricin to nervous cells [13]. Toxic type 2 RIPs, like other lectins, are retrogradely transported along axons, and have been used to produce selective lesions in the nervous system by a technique termed 'molecular neurosurgery'.…”