Comprehensive analysis of lysine crotonylation in proteome of maintenance hemodialysis patients

INTRODUCTION: Histone post-translational modifications (PTMs) carry epigenetic information to regulate diverse cellular processes at the chromatin level. Crotonylation, one of the most important and common PTMs, plays a key role in the regulation of various biological processes. However, no study has evaluated the role of lysine crotonylation in maintenance hemodialysis patients (MHP). METHODS: Here, we comparatively evaluated the crotonylation proteome of normal controls (NC) and MHP using liquid chromatography tandem mass spectrometry (LC-MS/MS) coupled with highly sensitive immune-affinity purification. RESULTS: A total of 1109 lysine modification sites distributed on 347 proteins were identified, including 93 and 252 crotonylated upregulated and downregulated proteins, respectively. Thus, a decrease in crotonylation of histone proteins was observed in patients with kidney failure undergoing maintenance hemodialysis. Intensive bioinformatic analysis revealed that most of the crotonylated proteins were distributed in the cytoplasm, nucleus, mitochondria, and extracellular region. Gene ontology enrichment analysis showed that the crotonylated proteins were significantly enriched in the platelet alpha granule lumen, platelet degranulation, and cell adhesion molecule binding. In addition, protein domain, including fibrinogen alpha/beta/gamma chain, zinc finger, and WD40-repeat-containing domain, were significantly enriched in crotonylated proteins. Kyoto Encyclopedia of Genes and Genomes (KEGG)-based functional enrichment analysis revealed that crotonylated proteins were enriched in complement and coagulation cascades, cardiac muscle contraction, and hematopoietic cell lineage, all of which have important associations with hemodialysis complications. CONCLUSIONS: This is the first report on the global crotonylation proteome of MHP. Lysine crotonylation was found to play important regulatory roles in pathophysiological processes in MHP.