NAA enhances cell yields by inhibiting apoptosis pathway
The in vitro cell culturing witnessed its applications in both scientific research and industrial activities, its optimization leads to practical benefits, either through shortening the doubling time, or simplification of engineering requests, or both. Literature searching highlighted a role of a synthetic auxin derivative 1-Naphthaleneacetic acid (NAA) in optimizing plant cell culturing. Here, by measuring  cell counts and their activities via CCK8 tests, we observed an up to 2-fold increase in the yield of in vitro cultured human cells. We tested different types of human cell lines and primary natural killer cells, found that NAA was effective in all the cells tested. The PI staining and FACS analysis suggested that NAA did not affect the cell cycling. Apoptosis-specific dye staining analysis implicated that NAA rescued cell death. We further did bulk RNA sequencing and identified the lipid metabolism-engaging and anti-apoptosis gene, ANGPTL4, was enhanced in expression upon NAA treatment. Studies on ANGPTL4 knockout cells indicated that ANGPTL4 is required for NAA-mediated response. Thus, our data identified a beneficial role of NAA in human cell culturing and highlighted its potency in the in vitro cell culturing Overall design: In order to explore the effect of plant auxin NAA on the function of mammalian cells, we tested NAA in different cancer cells. It was found that 300um NAA could improve the proliferation of many cell lines, and this proliferation effect was caused by inhibiting apoptosis. RNA-seq analysis showed that NAA interacted with intracellular ANGPTL4 to exert anti-apoptosis effect, and explored the functional effect of NAA in animal cells.