👤 Eleanor Sanderson

We tested whether genetically proxied non-high-density lipoprotein cholesterol (non-HDL-C)-lowering drug targets reduce risk of all-cause dementia. We included 1,091,775 individuals from three prospective general population cohorts with individual-level data and two consortia with summary-level data. We selected genetic variants within HMGCR, NPC1L1, PCSK9, ANGPTL4, LPL, and CETP associated with non-HDL-C. These variants were used as exposures in Cox regression and one- and two-sample Mendelian randomization. Results were meta-analyzed. Meta-analysis of one-sample Mendelian randomization odds ratios per 1 mmol/L (39 mg/dL) lower non-HDL-C was 0.24 (0.18-0.31) for HMGCR, 0.18 (0.12-0.25) for NPC1L1, 0.97 (0.70-1.35) for PCSK9, 1.66 (0.52-5.36) for ANGPTL4, 1.41 (0.63-3.16) for LPL, and 0.30 (0.26-0.34) for CETP. Cox regression and two-sample Mendelian randomization results were mostly directionally consistent. Genetic lowering of non-HDL cholesterol via HMGCR, NPC1L1, and CETP reduces the risk of dementia. This reflects the effect of lifelong differences in non-HDL cholesterol on risk of dementia. Variants in HMGCR, NPC1L1, and CETP reduce the risk of dementia via non-high-density lipoprotein cholesterol (non-HDL-C). An effect of PCSK9, ANGPTL4, and LPL variants on dementia risk cannot be excluded. This reflects the effect of lifelong lower non-HDL-C on risk of dementia. Show less

Little is known about the role of the transcription factor peroxisome proliferator-activated receptor (PPAR) beta/delta in liver. Here we set out to better elucidate the function of PPARbeta/delta in liver by comparing the effect of PPARalpha and PPARbeta/delta deletion using whole genome transcriptional profiling and analysis of plasma and liver metabolites. In fed state, the number of genes altered by PPARalpha and PPARbeta/delta deletion was similar, whereas in fasted state the effect of PPARalpha deletion was much more pronounced, consistent with the pattern of gene expression of PPARalpha and PPARbeta/delta. Minor overlap was found between PPARalpha- and PPARbeta/delta-dependent gene regulation in liver. Pathways upregulated by PPARbeta/delta deletion were connected to innate immunity and inflammation. Pathways downregulated by PPARbeta/delta deletion included lipoprotein metabolism and various pathways related to glucose utilization, which correlated with elevated plasma glucose and triglycerides and reduced plasma cholesterol in PPARbeta/delta-/- mice. Downregulated genes that may underlie these metabolic alterations included Pklr, Fbp1, Apoa4, Vldlr, Lipg, and Pcsk9, which may represent novel PPARbeta/delta target genes. In contrast to PPARalpha-/- mice, no changes in plasma free fatty acid, plasma beta-hydroxybutyrate, liver triglycerides, and liver glycogen were observed in PPARbeta/delta-/- mice. Our data indicate that PPARbeta/delta governs glucose utilization and lipoprotein metabolism and has an important anti-inflammatory role in liver. Overall, our analysis reveals divergent roles of PPARalpha and PPARbeta/delta in regulation of gene expression in mouse liver. Show less