title: Protein arginine methylation is more prone to inhibition by S-adenosylhomocysteine than DNA methylation in vascular endothelial cells.
abstract: Methyltransferases use S-adenosylmethionine (AdoMet) as methyl group donor, forming S-adenosylhomocysteine (AdoHcy) and methylated substrates, including DNA and proteins. AdoHcy inhibits most methyltransferases. Accumulation of intracellular AdoHcy secondary to Hcy elevation elicits global DNA hypomethylation. We aimed at determining the extent at which protein arginine methylation status is affected by accumulation of intracellular AdoHcy. AdoHcy accumulation in human umbilical vein endothelial cells was induced by inhibition of AdoHcy hydrolase by adenosine-2,3-dialdehyde (AdOx). As a measure of protein arginine methylation status, the levels of monomethylarginine (MMA) and asymmetric and symmetric dimethylated arginine residues (ADMA and SDMA, respectively) in cell protein hydrolysates were measured by HPLC. A 10% decrease was observed at a 2.5-fold increase of intracellular AdoHcy. Western blotting revealed that the translational levels of the main enzymes catalyzing protein arginine methylation, protein arginine methyl transferases (PRMTs) 1 and 5, were not affected by AdoHcy accumulation. Global DNA methylation status was evaluated by measuring 5-methylcytosine and total cytosine concentrations in DNA hydrolysates by LC-MS/MS. DNA methylation decreased by 10% only when intracellular AdoHcy concentration accumulated to 6-fold of its basal value. In conclusion, our results indicate that protein arginine methylation is more sensitive to AdoHcy accumulation than DNA methylation, pinpointing a possible new player in methylation-related pathology.
authors: Institute for Medicines and Pharmaceutical Sciences (iMed.UL), Faculty of Pharmacy, University of Lisbon, Lisbon, Portugal.
authors: Ruben
authors: R
authors: Esse
authors: Monica S
authors: MS
authors: Rocha
authors: Madalena
authors: M
authors: Barroso
authors: Cristina
authors: C
authors: Florindo
authors: Tom
authors: T
authors: Teerlink
authors: Robert M
authors: RM
authors: Kok
authors: Yvo M
authors: YM
authors: Smulders
authors: Isabel
authors: I
authors: Rivera
authors: Paula
authors: P
authors: Leandro
authors: Pieter
authors: P
authors: Koolwijk
authors: Rita
authors: R
authors: Castro
authors: Henk J
authors: HJ
authors: Blom
authors: Isabel Tavares
authors: IT
authors: de Almeida
mesh_terms: D001120:Arginine / Q000378:metabolism*; D002478:Cells, Cultured; D019175:DNA Methylation; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012436:S-Adenosylmethionine / Q000378:metabolism*
chemical_list: D012436:S-Adenosylmethionine; D001120:Arginine