Table 1.

Epigenetic dysregulation in aging: DNA (de)methylation.

Gene	Regulation	Epigenetic modification	Observed in	Sample size	Approach	Methods	Reference
GABRA2	↑	Methylation	Human	125	Targeted	BS, Methylight PCR	Siegmund et al., 2007
GAD1	↑	(promoter region)			(50 loci)
HOXA1	↑
NEUROD1	↑
NEUROD2	↑
PGR	↑
STK11	↑
SYK	↑
IFN-γ	↑↑			784	Targeted (9 loci)	BS	Madrigano et al., 2012
RUNX3	↑↑			26	Targeted (7 loci)	BS, MS-PCR	So et al., 2006
ERß	↑↑			7–10	Targeted (1 locus)	BS, MS-PCR, Pyrosequencing, ChIP	Westberry et al., 2011
APP	↓	Methylation	Human	16	Targeted	BS	Tohgi et al., 1999
GCF	↓	Methylation (binding sites)			(18 loci)
SP1	↑↑	Methylation (interaction sites)

Protein/(Hydroxy) Methylated base	Regulation	Modification in	Observed in	Sample size	Methods	Reference
DNMT1	↓	Expression	Fibroblasts (fetal lung)	-	DNMT assay ChIP, RT-PCR	Lopatina et al., 2002; Pan et al., 2013
DNMT3a2	↓		Mice (12 month old)	15	IHC	Oliveira et al., 2012
DNMT3a	↑		Mouse Hippocampus	48	IHC	Chouliaras et al., 2011a
5-mC	↑		(DG, CA1–2 and 3)			Chouliaras et al., 2011b
5-hmC	↑			4	HPLC	Munzel et al., 2010; Song et al., 2011b

^↑indicates increased expression levels and

^↓indicates decreased expression levels.

Abbreviations: 5-hmC, 5-hydroxymethylcytosine; 5-mC, 5-methylcytosine; APP, amyloid β precursor protein; CA, cornu ammonis; DG, dentate gyrus; DNMT, DNA methyltransferase; ER, estrogen receptor; GABRA2, γ-aminobutyric acid receptor subunit alpha-2; GAD1, glutamate decarboxylase 1; GCF, granulocyte chemotactic factor; HOXA1, homeobox protein A1; IFN-γ, interferon γ; NEUROD, neurogenic differentiation factor; PGR, progesterone receptor; RUNX3, runt-related transcription factor 3; SP1, specificity factor 1; STK11, serine/threonine kinase 11; SYK, spleen tyrosine kinase; BS, bisulfite sequencing; PCR, polymerase chain reaction; MS-PCR, methylation specific-PCR; RT-PCR, real time-PCR; ChIP; chromatin immunoprecipitation; IHC, immunohistochemistry; HPLC: high-performance liquid chromatography.