Leukemia inhibitory factor

Leukemia inhibitory factor, or LIF, is a cytokine of the interleukin-6 family that regulates cell growth by suppressing differentiation; when LIF levels fall, affected cells begin to differentiate. It signals by binding to the LIF receptor alpha subunit, which pairs with the shared gp130 signal-transducing subunit to activate the JAK-STAT and MAPK signaling cascades inside the cell. Its best-established practical use is in stem cell culture, where recombinant LIF is added to culture media as an alternative to feeder cell layers, promoting self-renewal of pluripotent stem cells by recruiting the transcription factor STAT3 and reducing spontaneous differentiation during laboratory expansion. Recombinant LIF has also been produced experimentally in rice plants as an alternative manufacturing method for stem-culture-grade material. Beyond laboratory use, LIF has been studied in reproductive medicine, where research suggests recombinant human LIF might improve embryo implantation rates in women with unexplained infertility, building on evidence that p53-regulated LIF supports embryo implantation in mouse models and potentially in humans, though this reproductive application remains investigational rather than an approved therapeutic use.