Nutrient Deprivation Elicits a Transcriptional and Translational Inflammatory Response Coupled to Decreased Protein Synthesis

Abstract

Summary: Nutrient deprivation inhibits mRNA translation through mTOR and eIF2α signaling, but it is unclear how the translational program is controlled to reflect the degree of a metabolic stress. In a model of breast cellular transformation, various forms of nutrient deprivation differentially affect the rate of protein synthesis and its recovery over time. Genome-wide translational profiling of glutamine-deprived cells reveals a rapid upregulation of mRNAs containing uORFs and downregulation of ribosomal protein mRNAs, which are followed by selective translation of cytokine and inflammatory mRNAs. Transcription and translation of inflammatory and cytokine genes are stimulated in response to diverse metabolic stresses and depend on eIF2α phosphorylation, with the extent of stimulation correlating with the decrease in global protein synthesis. In accord with the inflammatory stimulus, glutamine deprivation stimulates the migration of transformed cells. Thus, pro-inflammatory gene expression is coupled to metabolic stress, and this can affect cancer cell behavior upon nutrient limitation. : Deprivation of some nutrients may impose more constraints on mRNA translation than others. Gameiro and Struhl describe a relationship between translational repression and pro-inflammatory gene expression in response to various metabolic stresses. The pro-inflammatory transcriptional and translational response is not triggered by mTOR inhibition, per se, and requires eIF2α phosphorylation. Keywords: inflammation, glutamine, metabolism, translational control, protein synthesis, cancer, mTOR, eIF2α