Ces1g, also known as carboxylesterase 1g/esterase-x, is a carboxylesterase enzyme. It plays a role in metabolic control, particularly in lipid metabolism pathways, and is important for maintaining normal physiological functions related to lipid homeostasis [1,2]. Genetic models, especially knockout mouse models, have been crucial for studying its functions.

Ces1g -/- Ldlr -/- double knockout (DKO) mice, when fed a Western diet, showed decreased plasma cholesterol and TG levels and reduced atherosclerotic lesions compared to Ldlr -/- mice. Global inactivation of Ces1g inhibited intestinal cholesterol and fat absorption, increased macrophage cholesterol efflux, and promoted M2 macrophage polarization [1]. In contrast, knockdown of hepatic Ces1g in Apoe -/- mice led to hyperlipidemia and exacerbated atherogenesis [1]. Also, Ces1g deficiency in mice resulted in weight gain, insulin resistance, fatty liver, and hyperlipidemia, while restoration of its expression only in the liver reduced hepatic steatosis and improved insulin signaling [2].

In conclusion, Ces1g plays a critical role in lipid metabolism. Studies using Ces1g -/- mouse models have revealed its importance in preventing atherosclerosis and maintaining normal lipid and insulin-related physiological states, highlighting its potential as a target for treating lipid-related diseases.

References:

1. Xu, Jiesi, Xu, Yang, Xu, Yanyong, Yin, Liya, Zhang, Yanqiao. 2017. Global inactivation of carboxylesterase 1 (Ces1/Ces1g) protects against atherosclerosis in Ldlr -/- mice. In Scientific reports, 7, 17845. doi:10.1038/s41598-017-18232-x. https://pubmed.ncbi.nlm.nih.gov/29259301/

2. Bahitham, Wesam, Watts, Russell, Nelson, Randal, Lian, Jihong, Lehner, Richard. 2016. Liver-specific expression of carboxylesterase 1g/esterase-x reduces hepatic steatosis, counteracts dyslipidemia and improves insulin signaling. In Biochimica et biophysica acta, 1861, 482-90. doi:10.1016/j.bbalip.2016.03.009. https://pubmed.ncbi.nlm.nih.gov/26976727/