Changed Histone Acetylation Patterns in Normal-Appearing White Matter and Early Multiple Sclerosis Lesions

Dysregulated expression of downstream effectors of developmental myelination pathway in the NAWM of a subset of patients with chronic MS. Quantitative real-time PCR analysis of transcripts involved in the Wnt (i.e., TCF7L2), BMP4 (i.e., ID2), and Notch (i.e., JAG1) pathway. The levels of the neural stem cell marker SOX2, myelin genes (i.e., MAL, MOG, and MBP), and tubulin α (TUBA) were also determined. The RNA was isolated from NAWM samples from the frontal lobes of patients with chronic MS and non-neurological controls. The values of the qRT-PCR of the target genes were referred to those of transcripts for the ribosomal protein 60S subunit. Note that the same patients with high levels of TCF7L2 were also the ones with high levels of ID2 and SOX2. Each patient is identified by the same color in all diagrams (two-tailed t test with Welch's correction; *p < 0.05; **p < 0.01).

Correlation between TCF7L2 and MOG transcripts levels. A, Linear regression curve addressing the relations between TCF7L2 and MOG transcript levels in control and MS patients. Note the presence of two subgroups of female patterns, one displaying a linear positive correlation between the two variables and one with a negative correlation. No correlation was detected in males. B, Correlation plot between TCF7L2 transcripts levels and disease duration in MS patients. Linear regression of the female but not male transcript levels is significantly different from zero; p < 0.05.

Selective changes of histone deacetylase transcript levels in the frontal lobes of chronic MS brains. Quantitative RT-PCR of RNA isolated from white matter samples in the frontal cortex of non-neurological controls and MS patients to detect transcript levels of histone deacetylases. The relative levels of expression were first normalized to the transcript levels of the ribosomal protein of the 60S subunit and then expressed as fold changes over the average values calculated in male or female non-neurological controls. The individual values are shown as triangles for females and circles for males. The median value of the ranking distribution is shown by a line.

Increased levels of histone acetyltransferase transcripts in the frontal lobes of a subset of patients with chronic MS. Quantitative RT-PCR of RNA isolated from white matter samples in the frontal cortex of non-neurological controls and MS patients to detect transcript levels of distinct classes of histone acetyltransferases, including MYST3, MYST4, and TIP60 (A), and P300, PCAF, GCN5, and CBP (B). The relative levels of expression were normalized to the levels of 60S RNA protein transcripts and then expressed as fold changes over the average values calculated in male or female non-neurological controls. The individual values are shown as triangles for females and circles for males. The median value of the ranking distribution is shown by a line. Note the increased levels of P300 and CBP in female MS patients compared with controls (two-tailed t test with Welch's correction; *p < 0.05; **p < 0.01). C, Correlation between P300 or CBP levels and TCF7L2. Linear regression of female but not male MS patients is significantly different from zero; p < 0.05.

Increased histone H3 acetylation in the region corresponding to TCF7L2, and TUBA, in chromatin samples from MS patients. A, B, TCF7L2 and TUBA gene loci from UCSC genome browser. The regions amplified in the ChIP experiment are shown as black boxes. C, D, After isolation of chromatin from the NAWM of the frontal lobes of patients with chronic MS and non-neurological controls, samples were immunoprecipitated with antibodies against acetyl-H3 and then assayed using quantitative PCR. The values are referred as percentage of enrichment of the signal in the immunoprecipitated samples relative to nonprecipitated chromatin (i.e., input control). Note the more prominent acetylation in female MS patients compared with controls detected at the TCF7L2 locus (C), but not at the constitutively expressed TUBA locus (D) patients (two-tailed t test with Welch's correction; *p < 0.05; **p < 0.01). Error bars indicate SEM.