Question: Are microRNA (miR) regulated through DNA methylation of their promoters?

Context:
We found that Tcf3 down-regulation in the context of constitutively active Wnt signaling does not result from promoter DNA methylation but is likely to be caused by a plethora of mechanisms at both the RNA and protein level as shown by the observed decrease in activating histone marks (H3K4me3 and H3-acetylation) and the upregulation of miR-211, a novel Wnt-regulated microRNA that targets Tcf3 and attenuates early neural differentiation in mouse ESCs
ene silencing of MIR22 in acute lymphoblastic leukaemia involves histone modifications independent of promoter DNA methylation
Whereas a CpG island was identified within the promoter element of MIR22, no promoter DNA methylation was detected in these cells
xtensive promoter DNA hypermethylation and hypomethylation is associated with aberrant microRNA expression in chronic lymphocytic leukemia
Integration of DNA methylation and miRNA promoter data led to the identification of 128 recurrent miRNA targets for aberrant promoter DNA methylation
Together, our findings characterize the role of epigenetic changes in the regulation of miRNA transcription and create a repository of disease-specific promoter regions that may provide additional insights into the pathogenesis of CLL
NA methylation of microRNA genes in multiple myeloma
Recently, epigenetic dysregulation of tumor-suppressor miRNA genes by promoter DNA methylation has been implicated in human cancers, including multiple myeloma (MM)
ethylation of tumor suppressor microRNAs
Dysregulation of miRNA expression involved in cancer can be triggered by multiple mechanisms including aberrant DNA methylation of the miRNA gene promoter
Of note, DNA methylation of tumor suppressor miRNAs has been implicated in various human cancers
Moreover, miRNA silencing mediated by aberrant promoter DNA methylation can potentially be reversed by hypomethylating agents, and hence may pose a new therapeutic target in cancer
 In this review, the authors will focus on the aberrant methylation of miRNAs in the pathogenesis of lymphoid malignancies including chronic lymphocytic leukemia, multiple myeloma and acute lymphoblastic leukemia
Here, we review those miRNAs implicated in AD that are regulated by promoter DNA methylation and/or chromatin modifications and, which frequently direct the expression of constituents of the epigenetic machinery, concluding with the delineation of a complex epigenetic-miRNA regulatory network and its alterations in AD
Furthermore, we also discuss epigenetic dysregulation of tumor-suppressor miRNA genes by promoter DNA methylation and the interaction of DNA methylation with miRNAs involved in the regulation of HSC activation and liver fibrosi
Instead, the cell type-specific silencing of these genes is due to enhanced p21 mRNA degradation, 14-3-3sigma promoter DNA methylation and reduced processing of the miR-34a primary transcript
Some tumor-suppressive miRNAs are known to be epigenetically silenced by promoter DNA methylation in cancer
In the present study, we aimed to identify miRNA genes that are silenced by DNA hypermethylation in hepatocellular carcinoma (HCC)
It was found that miR-335, which is harbored within an intron of its protein-coding host gene, MEST, was downregulated by aberrant promoter hypermethylation via further methylation assays, including methylation-specific PCR, combined bisulfite and restriction analysis, bisulfite sequencing analysis and 5-aza-2'-deoxycytidine treatment
he levels of miR-335/MEST methylation were significantly higher in 18 (90%) out of 20 primary HCC tumors, compared to their non-tumor tissue counterparts (P<0.001)
In conclusion, our results indicate that expression of miR-335 is reduced by aberrant DNA methylation in HCC.

Answer: Dysregulation of miRNA expression involved in cancer and Alzheimer's disease can be triggered by multiple mechanisms including aberrant DNA methylation of the miRNA gene promoter. Epigenetic dysregulation of tumor-suppressor miRNA genes by promoter DNA methylation has been implicated in human cancers, including multiple myeloma (MM).
Dysregulation of miRNA expression involved in cancer can be triggered by multiple mechanisms including aberrant DNA methylation of the miRNA gene promoterRecently, epigenetic dysregulation of tumor-suppressor miRNA genes by promoter DNA methylation has been implicated in human cancers, including multiple myeloma (MM)
Exact answer: yes