A mutation in the 3′-UTR of the HDAC6 gene abolishing the post-transcriptional regulation mediated by hsa-miR-433 is linked to a new form of dominant X-linked chondrodysplasia

Abstract

A family with dominant X-linked chondrodysplasia was previously described. The disease locus was ascribed to a 24 Mb interval in Xp11.3-q13.1. We have identified a variant (c.*281A>T) in the 3' untranslated region (UTR) of the HDAC6 gene that totally segregates with the disease. The variant is located in the seed sequence of hsa-miR-433. Our data showed that, in MG63 osteosarcoma cells, hsa-miR-433 (miR433) down-regulated both the expression of endogenous HDAC6 and that of an enhanced green fluorescent protein-reporter mRNA bearing the wild-type 3'-UTR of HDAC6. This effect was totally abrogated when the reporter mRNA bore the mutated HDAC6 3'-UTR. The HDAC6 protein was found to be over-expressed in thymus from an affected male fetus. Concomitantly, the level of total alpha-tubulin, a target of HDAC6, was found to be increased in the affected fetal thymus, whereas the level of acetylated alpha-tubulin was found to be profoundly decreased. Skin biopsies were obtained from a female patient who presented a striking body asymmetry with hypotrophy of the left limbs. The mutated HDAC6 allele was expressed in 31% of left arm-derived fibroblasts, whereas it was not expressed in the right arm. Overexpression of HDAC6 was observed in left arm-derived fibroblasts. Altogether these results strongly suggest that this HDAC6 3'-UTR variant suppressed hsa-miR-433-mediated post-transcriptional regulation causing the overexpression of HDAC6. This variant is likely to constitute the molecular cause of this new form of X-linked chondrodysplasia. This represents to our knowledge the first example of a skeletal disease caused by the loss of a miRNA-mediated post-transcriptional regulation on its target mRNA.

Analysis of post-transcriptional regulation using the FunREG method

“…Although less potent than the siRNA, but in agreement with the literature [14,15], miR-98 and Let7a efficiently reduced eGFP expression through c-myc 3 -UTR by destabilizing the mRNA, with limited effects on translation efficiency [35]. Finally, we assessed the capacity of FunREG to reveal post-transcriptional changes from one cell type to another in different pathological contexts (see [19,32]). We first compared cisARS function in cancerous and normal hepatocytes.…”

“…Genetic changes influencing mRNA decay or translation could also originate from normal events such as polymorphism [1]. In a collaborative work performed with our team, Benoît Arveiler and colleagues recently reported an example of such a genetic defect, which abrogates the regulation of HDAC6 (histone deacetylase 6) expression by miR-433 (see below and [19]). On the other hand, the expression of numerous transRFs (either RBP or miRNA) is altered in diseased tissues [1,10,17].…”

MicroRNA-221 governs tumor suppressor HDAC6 to potentiate malignant progression of liver cancer

“…15 For instance, miR-433 suppresses HDAC6 in human osteosarcoma cells, and a mutation of the miR-433-binding site in HDAC6 mRNA 3'-UTR negates this post-transcriptional regulation in dominant X-linked chondrodysplasia [28]. In addition, it has been reported that in mesenchymal stem cells derived from human adipose tissue, miR-22 promotes osteogenic differentiation and inhibits adipogenic differentiation by suppressing HDAC6 expression [29].…”

Limited efficacy of specific HDAC6 inhibition in urothelial cancer cells

“…The mechanisms involved in regulation of HDAC6 expression are poorly characterized, but interestingly, regulation by one specific micro-RNA, hsa-miR-433 is documented. 39 In order to exclude that factors like HIF1 and HSP90 may be involved we analyzed expression levels of both proteins. Especially HSP90 has been reported to regulate functional integrity and turnover of many proteins e.g., the androgen receptor.…”