Asns-flox Mouse

Asns, also known as asparagine synthetase (glutamine-hydrolyzing), is an enzyme that catalyzes the biosynthesis of asparagine, a non-essential amino acid. It is involved in multiple metabolic pathways, such as amino acid metabolism, and plays a crucial role in maintaining glutamine homeostasis [3]. Its function is essential for various biological processes, including cell differentiation and the response to metabolic stressors. Genetic models, like gene knockout mouse models, can be used to study its role in these processes.

In CD8+ T cells, the expression dynamics of Asns are critical for cell differentiation. Its expression peaks for effector T cells and decays during memory formation. Disrupting these dynamics by overexpressing Asns promotes an effector phenotype and enhances the anti-tumor response of adoptively transferred CD8+ T cells in a mouse melanoma model [1]. In osteosarcoma, NAT10 enhances the mRNA stability of ATF4 through ac4C modification, and ATF4 induces the transcription of Asns, which facilitates tumor progression. Inhibiting NAT10 suppresses osteosarcoma progression in vivo [2]. In clear cell renal cell carcinoma (ccRCC), Asns expression is increased, associated with advanced clinicopathological characteristics and T lymphocyte infiltration, and serves as an independent prognostic factor [4]. In acute liver injury, hepatocyte-specific Asns deletion in mice makes them more prone to pericentral liver damage after toxin exposure, and this can be reverted by intravenous administration of asparagine [5]. In pancreatic ductal adenocarcinoma (PDAC), inhibiting Asns by a glutamine antagonist reduces asparagine production and blocks tumor growth, and PDAC cells upregulate Asns as a metabolic adaptation [6].

In conclusion, Asns plays essential roles in cell differentiation, metabolism, and the response to stress in various biological systems. Studies using gene knockout or conditional knockout mouse models have revealed its significance in cancer, including melanoma, osteosarcoma, ccRCC, and PDAC, as well as in acute liver injury. Understanding Asns function provides insights into disease mechanisms and potential therapeutic targets.