Figure 3.

Marked toxicity of mutated SOD1–expressing astrocytes to motor neurons. (a,b) ESMNs show shorter axonal lengths (a) and smaller cell body diameters (b) when plated on AMLs expressing SOD1^G93A, compared with their counterparts plated on ^NTgAMLs (Kolmogorov-Smirnov test; P < 0.005). (c) The decay in numbers of ^eGFPPMNs plated on ^G93AAMLs is greater (F_3,37 = 6.3, P = 0.0015) than that of eGFPPMNs plated on NTgAMLs. (d) At 7 d after plating, there are consistently fewer ^eGFPPMNs (P < 0.01) in ^{G93A, G37R} and ^G85RAML cocultures than in ^NTgAML cocultures. However, ^WT and ^NTgAML cocultures have similar (P > 0.05) numbers of ^NTgPMNs. (e,f) ESMNs plated on either ^NTg or ^TgAMLs behave similarly to PMNs. (g) There are comparable numbers (P > 0.05) of ^NTg and ^G37RPMNs surviving at all time points after plating on ^NTgAMLs. There are fewer (*P < 0.01) ^NTg and ^G37RPMNs surviving on ^G93AAMLs than on ^NTgAMLs. The loss of ^G37RPMNs plated on ^G93AAMLs is comparable (P > 0.05) to that of ^NTgPMNs. Values represent means ± s.e.m. from at least three independent experiments performed at least in triplicate, analyzed by two-way ANOVA followed by a Newman-Keuls post hoc test. Tg, transgenic.