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. Author manuscript; available in PMC: 2018 May 17.
Published in final edited form as: Neuron. 2017 May 17;94(4):759–773.e8. doi: 10.1016/j.neuron.2017.04.043

Figure 1. Multiple astrocyte-secreted factors support microglial survival.

Figure 1

(A) Serum-free rat primary microglia cultured in basal medium or astrocyte conditioned medium (ACM, 20 μg/mL) for 5 days. ACM improved survival, as assessed by accumulation of calcein (green) and exclusion of ethidium dimers (red). (B) Dose-response curves of fractionated ACM. Survival activity of unfractionated ACM (black) was not fully recovered in either heparin column flowthrough (Hep FT, blue) or eluate (Hep EL, gray) fractions. Recovered activity with combined fractions (red) indicates multiple active components. Doses represent complete ACM protein concentration or equivalent volume of each fraction. Lines represent Hill equation fits. (C) Survival activity of the Hep EL fraction can be complemented by CSF-1 and TGF-β2. (D) Survival activity of the Hep FT fraction can be complemented by free cholesterol. Some data replotted from (C). Averages are mean ± sem. Scale bars = 80 μm. * P < 0.001 one-way ANOVA across all groups in the panel with Dunnett’s comparison to the leftmost (no additive) condition.