DUSP1 and asthma: In monocytes from asthma patients, vitamin D pretreatment increased glucocorticoid receptor binding to the DUSP1 (a gene encoding dual specificity phosphatase 1, a protein responsible for the inhibition of pro-inflammatory cytokines production) promoter and enhanced histone H4 acetylation at the glucocorticoid response elements of this genomic region [236].