Citation

  • Authors: Varlet AA. et al.
  • Year: 2022
  • Journal: Cells 11 50
  • Applications: in vitro / siRNA / INTERFERin
  • Cell type: Human primary fibroblasts
    Description: Primary human fibroblast cells

Method

For siRNA transfection, fibroblasts were seeded on coverslips at a density of 3.104 cells/well. INTERFERin® siRNA Transfection Reagent (Polyplus Transfection, Illkirch, France) was used to transfect 50 nM of either siRNA negative control or siRNA targeting LMNB2 mRNA. The efficiency of siRNA was analyzed 41 h post-transfection by immunofluorescence.

Abstract

Many proteins are causative for inherited partial lipodystrophies, including lamins, the essential constituents of the nuclear envelope scaffold called the lamina. By performing high throughput sequencing on a panel of genes involved in lipodystrophies, we identified a heterozygous mutation in LMNB2 gene (c.700C > T p.(Arg234Trp)) in a female patient presenting early onset type II diabetes, hypertriglyceridemia, and android fat distribution. This mutation is rare in the general population (frequency 0.013% in GnomAD) and was predicted pathogenic by a set of pathogenicity prediction software. Patient-derived fibroblasts showed nuclear shape abnormalities and premature senescence features, which are two typical cellular phenotypes associated with laminopathies. Moreover, we observed an atypical aggregation of lamin B2 in nucleoplasm, which co-distributes with emerin and lamin A/C, along with an abnormal distribution of lamin A/C at the nuclear envelope. Finally, reducing lamin B2 expression level by siRNA targeted toward LMNB2 transcripts resulted in decreased nuclear anomalies and senescence-associated beta-galactosidase, suggesting a role of the mutated protein in the occurrence of the observed cellular phenotype. Altogether, these results suggest that mutations in lamin B2 could produce premature senescence and partial lipodystrophy features as observed with certain mutants of lamin A/C.

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