Beneficial effects of Glc-1,6-P2 modulation on mutant phosphomannomutase-2

: The metabolite Glucose-1,6-bisphosphate (Glc-1,6-P2) plays a vital role in human metabolism, and is a crucial activator and stabilizer for phosphomannomutase-2 (PMM2) - mutations within this protein propagate the most common congenital disorder of glycosylation (PMM2-CDG). In vivo, Glc-1,6-P2 is hydrolysed by phosphomannomutase-1 (PMM1), predominantly in the brain, under the influence of inosine monophosphate (IMP). In the present study, we employed knock-out PMM1 in Arg141His/Phe119LeuPMM2 patient-derived fibroblasts and investigated the phenotypic improvement. Increased Glc-1,6-P2 was associated with glycosylation enhancement, confirmed by glycan profiling. The prevalence of previously identified PMM2-CDG biomarkers, such as LAMP1, PTX3 and lysosomal enzymes showed empirical increases - these findings were corroborated by metabolomic and proteomic analysis. Moreover, our results support the potential of Glc-1,6-P2 modulation for PMM2-CDG, potentiating novel perspectives in drug discovery.