A lipodystrophy-causing lamin A mutant alters conformation and epigenetic regulation of the anti-adipogenic <i>MIR335</i> locus

Abstract

Mutations in the <i>Lamin A/C</i> (<i>LMNA</i>) 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 <i>MIR335</i> microRNA gene in human adipocyte progenitor cells. The R482W mutation results in a loss of function of differentiation-dependent lamin A binding to the <i>MIR335</i> locus. This impairs H3K27 methylation and instead favors H3K27 acetylation on <i>MIR335</i> enhancers. The lamin A mutation further promotes spatial clustering of <i>MIR335</i> enhancer and promoter elements along with overexpression of the <i>MIR355</i> 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.