Major methylation alterations on the CpG markers of inflammatory immune associated genes after IVIG treatment in Kawasaki disease

Abstract

BackgroundKawasaki disease (KD) is an autoimmune disease preferentially attacking children younger than five years worldwide. So far, the principal treatment to KD is the administration of Intravenous immunoglobulin (IVIG). Although DNA methylation plays important regulation roles in diseases, few studies investigated the regulation roles of DNA methylation in KD.MethodsIn this study, we focused not only on the DNA methylation alterations resulted from KD onset but also on DNA methylation alterations resulted from IVIG administration. To do so, we investigated the effects of KD’s onset and IVIG administration on CpG marker’s methylation alterations.ResultsWe first found that DNA methylation alterations reflecting disease onset or IVIG administration are contributed mainly by the CpG markers on autosomes. In addition, we also demonstrated that some CpG markers carry methylation alteration among samples, forcing the expression abundance of the downstream genes to be also altered and negatively correlated with methylation profile. Finally, compared with KD’s onset, IVIG administration brings stronger impact on methylation alteration. And, such alterations were conducted mainly by hyper-methylating CpG markers, forcing the corresponding genes to keep lower expression levels. Moreover, the genes regulated by the altered CpG markers with IVIG administration are enriched in the pathways associated with inflammatory immune response.ConclusionsIn summary, our result provides researchers with another way into the regulation mechanism through which IVIG represses excessive inflammatory responses.

HAMP promoter hypomethylation and increased hepcidin levels as biomarkers for Kawasaki disease

“…We collected whole blood samples from the subjects and then carried out white blood cell (WBC) enrichment [17,18]. We then collected the DNA samples with bisulfite using a technique that was previously described in another study [18,26].…”

“…The M450 K BeadChip program can detect approximately 450,000 CpG methylation markers and spans the entire human genome. We applied 200 ng of bisulfite-converted genomic DNA in each M450 K BeadChip assay according to the manufacturer's instructions [17,18]. Afterwards, we calculated the percentage of cytosine methylation for each CpG marker of every sample, which we referred to as β values.…”

“…Since hypomethylation resulted in gene expression [17], we determined that DNA methylation profiles were associated with gene expression. Plasma hepcidin expressions were higher in pre-IVIG KD patients than in the febrile controls and decreased after receiving IVIG CAL, coronary artery lesion; Hb, hemoglobin; The data are presented as mean ± standard error.…”

“…We have previously reported that IVIG administration significantly affects methylation pattern alterations in KD patients [17][18][19]. In short, DNA methylation can affect an inactive gene through DNA methyltransferases [20].…”

Epigenetic Regulation of Macrophage Marker Expression Profiles in Kawasaki Disease

“…DNA samples taken from the 12 healthy controls, and the 12 Kawasaki disease patients at two time points, 24 h prior to IVIG therapy (KD1) and 21 days after IVIG therapy (KD2) were then used to examine DNA methylation patterns of M1 and M2 macrophage surface markers. Two hundred nanograms of bisulfite-converted genomic DNA were then applied to the Illumina HumanMethylation450 (M450K) BeadChip assay as described in previously (11,17). Cytosine methylation percentages (β values) were then calculated for each CpG marker within in the promoter region of all M1 and M2 markers included.…”