Centro de Investigaciones en Química Biológica de Córdoba, CIQUIBIC, CONICET, and Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, the Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA, the Córdoba, Argentina.
Instituto de Farmacología Experimental de Córdoba, IFEC, CONICET, and Departamento de Farmacología Otto Orsingher, Facultad de Ciencias Químicas, the Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA, the Córdoba, Argentina.
J Nutr. 2023 Apr;153(4):979-987. doi: 10.1016/j.tjnut.2023.02.036. Epub 2023 Mar 2.
Post-translational modifications are key factors in the modulation of nuclear protein functions controlling cell physiology and an individual's health.
This study examined the influence of protein restriction during the perinatal period on the nuclear O-N-acetylgalactosamine (O-GalNAc) glycosylation of cells from the liver and parts of the brain in the rat.
Pregnant Wistar rats were divided into 2 groups on day 14 of pregnancy and fed ad libitum 1 of 2 isocaloric diets containing 24% (well-fed) or 8% (protein-restricted diet) casein until the end of the experiment. Male pups were studied after weaning at 30 d of life. Animals and their organ/tissues (liver, cerebral cortex, cerebellum and hippocampus) were weighed. Cell nuclei were purified, and the presence in nucleus and cytoplasm of all factors required for the initiation of O-GalNAc glycan biosynthesis, i.e., the sugar donor (UDP-GalNAc), enzyme activity (ppGalNAc-transferase) and the glycosylation product (O-GalNAc glycans), were evaluated by western blotting, fluorescent microscopy, enzyme activity, enzyme-lectin sorbent assay and mass spectrometry.
The perinatal protein deficit reduced progeny weight, as well as the cerebral cortex and cerebellum weight. UDP-GalNAc levels in the cytoplasm and nuclei of the liver, the cerebral cortex, cerebellum, or hippocampus were not affected by the perinatal dietary protein deficits. However, this deficiency affected the ppGalNAc-transferase activity localized in the cerebral cortex and hippocampus cytoplasm as well as in the liver nucleus, thus reducing the "writing" ppGalNAc-transferase activity of O-GalNAc glycans. In addition, liver nucleoplasm from protein-restricted offspring revealed a significant reduction in the expression of O-GalNAc glycans on important nuclear proteins.
Our results report an association between the consumption of a protein-restricted diet by the dam and her progeny with the modulation in the offspring' liver nuclei O-GalNAc glycosylation, which may ultimately regulate nuclear protein functions.
翻译后修饰是调节核蛋白功能、控制细胞生理学和个体健康的关键因素。
本研究探讨了围产期蛋白质限制对大鼠肝脏和部分脑区细胞核 O-N-乙酰半乳糖胺（O-GalNAc）糖基化的影响。
妊娠第 14 天，将 Wistar 孕鼠分为 2 组，分别给予 2 种等热量饮食，其中 1 种含 24%（充足喂养）或 8%（蛋白质限制饮食）酪蛋白，直至实验结束。雄性幼鼠于 30 日龄断奶后进行研究。称取动物及其器官/组织（肝脏、大脑皮质、小脑和海马）的重量。纯化细胞核，通过 Western 印迹、荧光显微镜、酶活性、酶-凝集素吸附试验和质谱法评估核和细胞质中所有起始 O-GalNAc 聚糖生物合成所需的因素（糖供体 UDP-GalNAc、酶活性（ppGalNAc-转移酶）和糖基化产物（O-GalNAc 聚糖）的存在情况。
围产期蛋白质缺乏降低了后代的体重以及大脑皮质和小脑的重量。细胞质和细胞核中 UDP-GalNAc 的水平在肝脏、大脑皮质、小脑或海马中不受围产期饮食蛋白质缺乏的影响。然而，这种缺乏影响了定位在大脑皮质和海马细胞质以及肝脏核中的 ppGalNAc-转移酶活性，从而降低了 O-GalNAc 聚糖的“书写”ppGalNAc-转移酶活性。此外，蛋白质限制后代的肝脏核质体显示 O-GalNAc 聚糖在重要核蛋白上的表达显著减少。
我们的研究结果报告了母体及其后代摄入限制蛋白质的饮食与后代肝脏核 O-GalNAc 糖基化的调节之间存在关联，这可能最终调节核蛋白的功能。
