Physiologic Responses to Dietary Sulfur Amino Acid Restriction in Mice Are Influenced by Atf4 Status and Biological Sex.

Background Dietary sulfur amino acid restriction (SAAR) improves body composition and metabolic health across several model organisms in part through induction of the integrated stress response (ISR). Objective We investigate the hypothesis that activating transcription factor 4 (ATF4) acts as a converging point in the ISR during SAAR. Methods Using liver-specific or global gene ablation strategies, in both female and male mice, we address the role of ATF4 during dietary SAAR. Results We show that ATF4 is dispensable in the chronic induction of the hepatokine fibroblast growth factor 21 while being essential for the sustained production of endogenous hydrogen sulfide. We also affirm that biological sex, independent of ATF4 status, is a determinant of the response to dietary SAAR. Conclusions Our results suggest that auxiliary components of the ISR, which are independent of ATF4, are critical for SAAR-mediated improvements in metabolic health in mice.