High prevalence of mutations in perilipin 1 in patients with precocious acute coronary syndrome

Perilipin 1: a systematic review on its functions on lipid metabolism and atherosclerosis in mice and humans

The function of perilipin 1 in human metabolism was recently highlighted by the description of PLIN1 variants associated with various pathologies. These include severe familial partial lipodystrophy and early onset acute coronary syndrome. Additionally, certain variants have been reported to have a protective effect on cardiovascular diseases. The role of this protein remains controversial in mice and variant interpretation in humans is still conflicting. This literature review has two primary objectives (i) to clarify the function of the PLIN1 gene in lipid metabolism and atherosclerosis by examining functional studies performed in cells (adipocytes) and mice and (ii) to understand the impact of PLIN1 variants identified in humans based on the variant's location within the protein and the type of variant (missense or frameshift). To achieve these objectives, we conducted an extensive analysis of the relevant literature on perilipin 1, its function in cellular models and mice, and the consequences of its mutations in humans. We also utilized bioinformatics tools and consulted the Human Genetics Cardiovascular Disease Knowledge Portal to enhance the pathogenicity assessment of PLIN1 missense variants.

A Rare Mutation in LMNB2 Associated with Lipodystrophy Drives Premature Cell Senescence

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.