Hepatocyte-Specific Phgdh-Deficient Mice Culminate in Mild Obesity, Insulin Resistance, and Enhanced Vulnerability to Protein Starvation

• Published in: Nutrients Vol. 13; no. 10; p. 3468
• Main Authors: Hamano, Momoko, Esaki, Kayoko, Moriyasu, Kazuki, Yasuda, Tokio, Mohri, Sinya, Tashiro, Kosuke, Hirabayashi, Yoshio, Furuya, Shigeki
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 29.09.2021; MDPI
• Subjects: Albumins; Body weight; Cell culture; Dehydrogenases; Enzymatic activity; Gene expression; Glucose; Glucose metabolism; Glucose tolerance; Hepatocytes; Inflammation; Inflammatory response; Insulin; Insulin resistance; insulin signaling; Insulin-like growth factors; Kinases; l -serine deficiency; L-Serine; Liver; Nutrition research; Obesity; Phgdh; Phosphoglycerate dehydrogenase; Physiology; Proteins; RNA polymerase; Software; Starvation; Steatosis; Stress response; United States > US; Japan
• ISSN: 2072-6643; 2072-6643
• DOI: 10.3390/nu13103468

l-Serine (Ser) is synthesized de novo from 3-phosphoglycerate via the phosphorylated pathway committed by phosphoglycerate dehydrogenase (Phgdh). A previous study reported that feeding a protein-free diet increased the enzymatic activity of Phgdh in the liver and enhanced Ser synthesis in the rat liver. However, the nutritional and physiological functions of Ser synthesis in the liver remain unclear. To clarify the physiological significance of de novo Ser synthesis in the liver, we generated liver hepatocyte-specific Phgdh KO (LKO) mice using an albumin-Cre driver. The LKO mice exhibited a significant gain in body weight compared to Floxed controls at 23 weeks of age and impaired systemic glucose metabolism, which was accompanied by diminished insulin/IGF signaling. Although LKO mice had no apparent defects in steatosis, the molecular signatures of inflammation and stress responses were evident in the liver of LKO mice. Moreover, LKO mice were more vulnerable to protein starvation than the Floxed mice. These observations demonstrate that Phgdh-dependent de novo Ser synthesis in liver hepatocytes contributes to the maintenance of systemic glucose tolerance, suppression of inflammatory response, and resistance to protein starvation.