Iranian Journal of Basic Medical Sciences

Iranian Journal of Basic Medical Sciences

Down-regulation of AGXT2L1 promotes the development of nonalcoholic fatty liver disease

Document Type : Original Article

Authors
Department of Radiation Oncology, Guangdong Provincial People’s Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China
10.22038/ijbms.2026.89567.19546
Abstract
Objective(s): To investigate the role of alanine-glyoxylate aminotransferase 2-like1 (AGXT2L1) in Nonalcoholic fatty liver disease (NAFLD) and its underlying mechanisms.
Materials and Methods: Changes in AGXT2L1 expression during NASH progression were analyzed using tissue samples, cell experiments, and animal models. RNA sequencing was performed on experimental mice to explore potential mechanisms by assessing inflammatory factors, cell apoptosis, and endoplasmic reticulum stress.
Results: Compared with normal tissues, AGXT2L1 expression was reduced in multiple liver diseases. Both in vitro and in vivo experiments confirmed that down-regulation of AGXT2L1 exacerbated NASH severity. RNA sequencing initially indicated that abnormal AGXT2L1 expression primarily affects phospholipid metabolism. Additionally, animal experiments showed that AGXT2L1 deficiency increased the number of apoptotic hepatocytes and elevated the expression of endoplasmic reticulum stress markers.
Conclusion: Decreased AGXT2L1 expression is an evident alteration in liver injury. It has been indicated that down-regulation of AGXT2L1 promotes NAFLD development, possibly through three pathways: activation of inflammatory responses, promotion of hepatocyte apoptosis, and enhancement of endoplasmic reticulum stress.
Keywords
Subjects

1. Quek J, Chan KE, Wong ZY, Tan C, Tan B, Lim WH, et al. Global prevalence of non-alcoholic fatty liver disease and non-alcoholic steatohepatitis in the overweight and obese population: A systematic review and meta-analysis. Lancet Gastroenterol Hepatol 2023; 8: 20-30.
2. Devarbhavi H, Asrani SK, Arab JP, Nartey YA, Pose E, Kamath PS. Global burden of liver disease: 2023 update. J Hepatol 2023; 79: 516-537.
3. Powell EE, Wong VW, Rinella M. Non-alcoholic fatty liver disease. Lancet 2021; 397: 2212-2224.
4. Teng ML, Ng CH, Huang DQ, Chan KE, Tan DJ, Lim WH, et al. Global incidence and prevalence of nonalcoholic fatty liver disease. Clin Mol Hepatol 2023; 29: S32-S42.
5. Friedman SL, Neuschwander-Tetri BA, Rinella M, Sanyal AJ. Mechanisms of NAFLD development and therapeutic strategies. Nat Med 2018; 24: 908-922.
6. Grander C, Grabherr F, Tilg H. Non-alcoholic fatty liver disease: Pathophysiological concepts and treatment. Cardiovasc Res 2023; 119: 1787-1798.
7. Tilg H, Moschen AR. Evolution of inflammation in nonalcoholic fatty liver disease: The multiple parallel hits hypothesis. Hepatology 2010; 52: 1836-1846.
8. Tilg H, Adolph TE, Moschen AR. Multiple parallel hits hypothesis in nonalcoholic fatty liver disease: Revisited after a decade. Hepatology 2021; 73: 833-842.
9. Van der Veen JN, Kennelly JP, Wan S, Vance JE, Jacobs RL, Vance DE. The critical role of phosphatidylcholine and phosphatidylethanolamine metabolism in health and disease. Biochim Biophys Acta Biomembr 2017; 1859: 1558-1572.
10. Rong S, Xia M, Vale G, Wang S, Kim CW, Li S, et al. DGAT2 inhibition blocks SREBP-1 cleavage and improves hepatic steatosis by increasing phosphatidylethanolamine in the ER. Cell Metab 2024; 36: 617-629.
11. Petkevicius K, Palmgren H, Glover MS, Ahnmark A, Andréasson AC, Madeyski-Bengtson K, et al. TLCD1 and TLCD2 regulate cellular phosphatidylethanolamine composition and promote the progression of non-alcoholic steatohepatitis. Nat Commun 2022; 13: 6020.
12. Gibellini F, Smith TK. The Kennedy pathway--De novo synthesis of phosphatidylethanolamine and phosphatidylcholine. IUBMB Life 2010; 62: 414-428.
13. Ballesteros U, González-Ramirez EJ, de la Arada I, Sot J, Etxaniz A, Goñi FM, et al. Effects of a N-maleimide-derivatized phosphatidylethanolamine on the architecture and properties of lipid bilayers. Int J Mol Sci 2023; 24: 16570.
14. Korbecki J, Bosiacki M, Kupnicka P, Barczak K, Ziętek P, Chlubek D, et al. Biochemistry and diseases related to the interconversion of phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine. Int J Mol Sci 2024; 25: 10745.
15. Vance JE. Phospholipid synthesis and transport in mammalian cells. Traffic 2015; 16: 1-18.
16. Shama S, Jang H, Wang X, Zhang Y, Shahin NN, Motawi TK, et al. Phosphatidylethanolamines are associated with nonalcoholic fatty liver disease (NAFLD) in obese adults and induce liver cell metabolic perturbations and hepatic stellate cell activation. Int J Mol Sci 2023; 24: 1034.
17. Veiga-da-Cunha M, Hadi F, Balligand T, Stroobant V, Van Schaftingen E. Molecular identification of hydroxylysine kinase and of ammoniophospholyases acting on 5-phosphohydroxy-L-lysine and phosphoethanolamine. J Biol Chem 2012; 287: 7246-7255.
18. Schiroli D, Cirrincione S, Donini S, Peracchi A. Strict reaction and substrate specificity of AGXT2L1, the human O-phosphoethanolamine phospho-lyase. IUBMB Life 2013; 65: 645-650.
19. Ding Q, Kang J, Dai J, Tang M, Wang Q, Zhang H, et al. AGXT2L1 is down-regulated in hepatocellular carcinoma and associated with abnormal lipogenesis. J Clin Pathol 2016; 69: 215-220.
20. Hernández-Alvarez MI, Sebastián D, Vives S, Ivanova S, Bartoccioni P, Kakimoto P, et al. Deficient endoplasmic reticulum-mitochondrial phosphatidylserine transfer causes liver disease. Cell 2019; 177: 881-895.
21. Deng Y, Wu L, Ding Q, Yu H. AGXT2L1 is downregulated in carcinomas of the digestive system. Oncol Lett 2020; 20: 1318-1326. 
22. Aissa AF, Tryndyak V, de Conti A, Melnyk S, Gomes TD, Bianchi ML, et al. Effect of methionine-deficient and methionine-supplemented diets on the hepatic one-carbon and lipid metabolism iثn mice. Mol Nutr Food Res 2014; 58: 1502-1512. 
23. Shao L, Vawter MP. Shared gene expression alterations in schizophrenia and bipolar disorder. Biol Psychiatry 2008; 64: 89-97.
24. Schillaci FA, Lanza G, Salluzzo MG, L’Episcopo F, Ferri R, Salemi M. The role of ETNPPL in dopaminergic neuron stability: Insights from neuromelanin-associated protein expression in Parkinson’s disease. Int J Mol Sci 2024; 25: 13107.
25. Pawlak M, Lefebvre P, Staels B. Molecular mechanism of PPAR action and its impact on lipid metabolism, inflammation and fibrosis in non-alcoholic fatty liver disease. J Hepatol 2015; 62: 720-733.
26. Chen H, Tan H, Wan J, Zeng Y, Wang J, Wang H, et al. PPAR-γ signaling in nonalcoholic fatty liver disease: Pathogenesis and therapeutic targets. Pharmacol Ther 2023; 245: 108391.