J Cell Biol. 2017 Sep 4;216(9):2731-2743. doi: 10.1083/jcb.201701043. Epub 2017 Jul 27.
A lipodystrophy-causing lamin A mutant alters conformation and epigenetic regulation of the anti-adipogenic MIR335 locus.
Oldenburg A1, Briand N1, Sørensen AL1, Cahyani I1, Shah A1, Moskaug JØ1,2, Collas P3,2.
Mutations in the Lamin A/C (LMNA) gene-encoding nuclear LMNA cause laminopathies, which include partial lipodystrophies associated with metabolic syndromes. The lipodystrophy-associated LMNA p.R482W mutation is known to impair adipogenic differentiation, but the mechanisms involved are unclear. We show in this study that the lamin A p.R482W hot spot mutation prevents adipogenic gene expression by epigenetically deregulating long-range enhancers of the anti-adipogenic MIR335 microRNA gene in human adipocyte progenitor cells. The R482W mutation results in a loss of function of differentiation-dependent lamin A binding to the MIR335 locus. This impairs H3K27 methylation and instead favors H3K27 acetylation on MIR335 enhancers. The lamin A mutation further promotes spatial clustering of MIR335 enhancer and promoter elements along with overexpression of the MIR355 gene after adipogenic induction. Our results link a laminopathy-causing lamin A mutation to an unsuspected deregulation of chromatin states and spatial conformation of an miRNA locus critical for adipose progenitor cell fate.