Abstract
Angiogenin is a 14 kDa protein originally identified as an angiogenic protein. Recent development has shown that angiogenin acts on both endothelial cells and neuronal cells. Loss-of-function mutations in the coding region of the ANG gene have recently been identified in patients with amyotrophic lateral sclerosis. Angiogenin has been shown to control motor neuron survival and protect neurons from apoptosis under various stress conditions. In this article, we characterize the anti-apoptotic activity of angiogenin in pluripotent P19 mouse embryonal carcinoma cells. Angiogenin prevents serum withdrawal-induced apoptosis. Angiogenin upregulates anti-apoptotic genes, including Bag1, Bcl-2, Hells, Nf-kappab and Ripk1, and downregulates pro-apoptotic genes, such as Bak1, Tnf, Tnfr, Traf1 and Trp63. Knockdown of Bcl-2 largely abolishes the anti-apoptotic activity of angiogenin, whereas the inhibition of Nf-kappab activity results in a partial, but significant, inhibition of the protective activity of angiogenin. Thus, angiogenin prevents stress-induced cell death through both the Bcl-2 and Nf-kappab pathways.