Fluorinated Galactoses Inhibit Galactose-1-Phosphate Uridyltransferase and Metabolically Induce Galactosemia-like Phenotypes in HEK-293 Cells.
Verena JanesSimona GrabanyJulien DelbrouckStéphane P VincentJohannes GottschalkLothar EllingFranz-Georg HanischPublished in: Cells (2020)
Genetic defects of human galactose-1-phosphate uridyltransferase (hGALT) and the partial loss of enzyme function result in an altered galactose metabolism with serious long-term developmental impairment of organs in classic galactosemia patients. In search for cellular pathomechanisms induced by the stressor galactose, we looked for ways to induce metabolically a galactosemia-like phenotype by hGALT inhibition in HEK293 cells. In kinetic studies, we provide evidence for 2-fluorinated galactose-1-phosphate (F-Gal-1-P) to competitively inhibit recombinant hGALT with a KI of 0.9 mM. Contrasting with hepatic cells, no alterations of N-glycoprofiles in MIG (metabolic induction of galactosemia)-HEK293 cells were revealed for an inducible secretory netrin-1 probe by MALDI-MS. Differential fluorescence-activated cell sorting demonstrated reduced surface expression of N-glycosylated CD109, EGFR, DPP4, and rhMUC1. Membrane raft proteomes exhibited dramatic alterations pointing to an affection of the unfolded protein response, and of targeted protein traffick. Most prominent, a negative regulation of oxidative stress was revealed presumably as a response to a NADPH pool depletion during reduction of Gal/F-Gal. Cellular perturbations induced by fluorinated galactoses in normal epithelial cells resemble proteomic changes revealed for galactosemic fibroblasts. In conclusion, the metabolic induction of galactosemia-like phenotypes in healthy epithelial/neuronal cells could support studies on the molecular pathomechanisms in classic galactosemia, in particular under conditions of low galactose stress and residual GALT activity.
Keyphrases
- induced apoptosis
- cell cycle arrest
- oxidative stress
- endoplasmic reticulum stress
- end stage renal disease
- single cell
- chronic kidney disease
- signaling pathway
- mass spectrometry
- endothelial cells
- stem cells
- cell death
- radiation therapy
- multiple sclerosis
- dna methylation
- dna damage
- binding protein
- blood brain barrier
- cell proliferation
- pi k akt
- quantum dots
- cell therapy
- extracellular matrix
- neoadjuvant chemotherapy
- induced pluripotent stem cells
- peritoneal dialysis