Mangione Renata, Cirnigliaro Lara, Saab Miriam Wissam, Pettinato Fabio, Barbato Alessandro, Distefano Alfio, Spina Enrico La, Lazzarino Giuseppe, Volti Giovanni Li, Longhitano Lucia, Tibullo Daniele, Pittalà Alessandra, Giallongo Cesarina, Di Pietro Valentina, Tabbi Giovanni, Longo Salvatore Antonio, Graziani Andrea, Tavazzi Barbara, Amorini Angela Maria, Lazzarino Giacomo, Barone Rita
Departmental Faculty of Medicine, UniCamillus, Saint Camillus International University of Health and Medical Sciences, Via di S. Alessandro 8, 00131, Rome, Italy.
Child Neuropsychiatry- Department of Clinical and Experimental Medicine, University of Catania, Via S. Sofia 89, 95123, Catania, Italy.
Sci Rep. 2025 May 7;15(1):15929. doi: 10.1038/s41598-025-98846-8.
Phosphomannomutase-2 (PMM2) deficiency represents the most common congenital disorder of glycosylation (CDG). Currently, little is known about cell metabolic alterations occurring in these patients. Here, we quantified compounds connected to protein glycosylation (GDP-mannose, UDP-derivatives), energy metabolism (high-energy phosphates, nicotinic coenzymes, oxypurines), oxidative/nitrosative stress (GSH, nitrite, nitrate) and free amino acids in extracts of peripheral blood mononucleated cells (PBMCs), of seven PMM2-CDG patients and ten control healthy donors. Besides marked GDP-mannose decrease, PBMCs of PMM2-CDG patients had higher UDP-glucose (UDP-Glc), UDP-galactose (UDP-Gal) and UDP-Glucuronic levels, lower ATP, GTP and UTP levels, abnormal ATP/ADP, ATP/AMP and NAD/NADH ratios, increased xanthine, uric acid and nitrite + nitrate levels, and decreased GSH and free amino acids concentrations. These results suggest a new, conceivable metabolic route leading to the increase of specific UDP-derivatives (UDP-Glc, UDP-Gal and UDP-Glucuronic), also potentially explaining the glycogen abnormalities recently found in PMM2-CDG patients. Altogether, this study highlighted various metabolic changes caused by PMM2 deficiency, illustrating the widespread effects of PMM2 mutations (beyond N-glycan biosynthesis) that may significantly vary depending on the cell line considered. Using PBMCs, as a cellular model of lower invasiveness than skin fibroblast, may advantage cell metabolism studies to investigate new therapies specifically targeted to PMM2 deficiency.
磷酸甘露糖变位酶-2（PMM2）缺乏症是最常见的先天性糖基化障碍（CDG）。目前，对于这些患者体内发生的细胞代谢改变知之甚少。在此，我们对7例PMM2-CDG患者和10例健康对照者外周血单个核细胞（PBMC）提取物中与蛋白质糖基化相关的化合物（GDP-甘露糖、UDP衍生物）、能量代谢（高能磷酸盐、烟碱辅酶、氧化嘌呤）、氧化/亚硝化应激（谷胱甘肽、亚硝酸盐、硝酸盐）和游离氨基酸进行了定量分析。除了GDP-甘露糖显著降低外，PMM2-CDG患者的PBMC中UDP-葡萄糖（UDP-Glc）、UDP-半乳糖（UDP-Gal）和UDP-葡萄糖醛酸水平较高，ATP、GTP和UTP水平较低，ATP/ADP、ATP/AMP和NAD/NADH比值异常，黄嘌呤、尿酸以及亚硝酸盐+硝酸盐水平升高，谷胱甘肽和游离氨基酸浓度降低。这些结果提示了一条新的、可设想的代谢途径，导致特定UDP衍生物（UDP-Glc、UDP-Gal和UDP-葡萄糖醛酸）增加，这也可能解释了最近在PMM2-CDG患者中发现的糖原异常。总之，本研究突出了PMM2缺乏引起的各种代谢变化，阐明了PMM2突变的广泛影响（超出N-聚糖生物合成），其可能因所考虑的细胞系不同而有显著差异。使用PBMC作为一种侵袭性低于皮肤成纤维细胞的细胞模型，可能有利于细胞代谢研究，以探索专门针对PMM2缺乏症的新疗法。
