Psoriatic T cells reduce epidermal turnover time and affect cell proliferation contributed from differential gene expression

Abstract Context Graves’ orbitopathy (GO) is an autoimmune disease that persists when immunosuppression is achieved. Orbital fibroblasts from GO patients display peculiar phenotypes even if not exposed to autoimmunity, possibly reflecting genetic or epigenetic mechanisms, which we investigated here. Objective We aimed to explore potential genetic or epigenetic differences using primary cultures of orbital fibroblasts from GO and control patients. Methods Cell proliferation, hyaluronic acid (HA) secretion, and HA synthases (HAS) were measured. Next-generation sequencing and gene expression analysis of the whole genome were performed, as well as real-time-PCR of selected genes and global DNA methylation assay on orbital fibroblasts from 6 patients with GO and 6 control patients from a referral center. Results Cell proliferation was higher in GO than in control fibroblasts. Likewise, HA in the cell medium was higher in GO fibroblasts. HAS-1 and HAS-2 did not differ between GO and control fibroblasts, whereas HAS-3 was more expressed in GO fibroblasts. No relevant gene variants were detected by whole-genome sequencing. However, 58 genes were found to be differentially expressed in GO compared with control fibroblasts, and RT-PCR confirmed the findings in 10 selected genes. We postulated that the differential gene expression was related to an epigenetic mechanism, reflecting diverse DNA methylation, which we therefore measured. In support of our hypothesis, global DNA methylation was significantly higher in GO fibroblasts. Conclusions We propose that, following an autoimmune insult, DNA methylation elicits differential gene expression and sustains the maintenance of GO.

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Histone acetylation is associated with differential gene expression in the rapid and robust memory CD8+ T-cell response

Blood ◽

10.1182/blood-2006-02-005520 ◽

2006 ◽

Vol 108 (10) ◽

pp. 3363-3370 ◽

Cited By ~ 47

Author(s):

Monchou Fann ◽

Jason M. Godlove ◽

Marta Catalfamo ◽

William H. Wood ◽

Francis J. Chrest ◽

...

Keyword(s):

Gene Expression ◽

T Cells ◽

T Cell ◽

Differential Gene Expression ◽

Cd8 T Cells ◽

Cd8 T Cell ◽

T Cell Response ◽

Memory Cd8 T Cells ◽

Differential Gene ◽

H3k9 Acetylation

Abstract To understand the molecular basis for the rapid and robust memory T-cell responses, we examined gene expression and chromatin modification by histone H3 lysine 9 (H3K9) acetylation in resting and activated human naive and memory CD8+ T cells. We found that, although overall gene expression patterns were similar, a number of genes are differentially expressed in either memory or naive cells in their resting and activated states. To further elucidate the basis for differential gene expression, we assessed the role of histone H3K9 acetylation in differential gene expression. Strikingly, higher H3K9 acetylation levels were detected in resting memory cells, prior to their activation, for those genes that were differentially expressed following activation, indicating that hyperacetylation of histone H3K9 may play a role in selective and rapid gene expression of memory CD8+ T cells. Consistent with this model, we showed that inducing high levels of H3K9 acetylation resulted in an increased expression in naive cells of those genes that are normally expressed differentially in memory cells. Together, these findings suggest that differential gene expression mediated at least in part by histone H3K9 hyperacetylation may be responsible for the rapid and robust memory CD8+ T-cell response.

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