Fig 2: Regulatory role of GATA4 in cellular and plasma TG homeostasis.a, b Quantification of TG (a) or TC (b) level in HepG2 cells treated with or without oleic acid (OA). P values and 95% CIs are indicated, and independent measurements of n = 5 are plotted. c Data for participants with plasma TG ≥ 200 mg/dl (left) and plasma TC ≥ 240 mg/dl (right) were retrieved from the TWB cohort and sequentially stratified by the rs2409674 and rs651821 genotypes. Mean values are indicated. Statistical difference between two groups was determined by the Student’s t test. d Immunoblot showing APOA5 expression and phosphorylation of GATA4 at serine 105 following treatment of HepG2 cells to phenylephrine. All blots derive from the same experiment and were processed in parallel. e Histogram showing the relative rs651821 site enrichment after ChIP with normal mouse IgG or anti-GATA4 using HepG2 and Huh7 cells treated with or without 20 μM phenylephrine for 3 h. f Quantification of OA-induced TG level in HepG2 cells co-treated with or without 10 nM silodosin and 20 μM phenylephrine. P values and 95% CIs are indicated, and independent measurements of n = 6 are plotted.

Fig 3: Integrated analyses to prioritize the causal variant at locus 11q23.3.a Regional association plot for hyperlipidemia in association with the top SNP rs662799 (purple diamond). The other GWAS-detected/imputed SNPs are displayed by color showing their degrees of linkage (r2) with rs662799. b The eQTL correlation between APOA5 expression and the rs651821 genotype (left) or rs662799 (right) in liver tissues, for which the plot and P values were queried from the GTEx Portal. c Visualization of epigenetic regulation in HepG2 cells including histone modifications, DNase hypersensitivity region (DHS), and transcription factor binding sites (TFBS) upstream of APOA5 (UCSC Genome Browser http://genome.ucsc.edu/cgi-bin/hgPublicSessions, session name: Liver_APOA5p). The locations of the two candidate SNPs (rs651821 and rs662799) as well as the previously described rs2266788 are indicated. DNA fragments used for reporter analysis in the present study are indicated (elements A to D).

Fig 4: Model of the regulatory mechanism for rs651821 mediating APOA5 expression through GATA4, thereby promoting TG hydrolysis in liver.The figure was created with BioRender.com.

Fig 5: ApoA-V Q252X associates with lipoproteins.125I radiolabeled WT or Q252X apoA-V recombinant protein was incubated with A. apoa5 KO and B. human plasma then separated by FPLC. Data shown as percent total eluted counts. Fractions corresponding to the elution range of VLDL, LDL and HDL particles are indicated. C. DMPC clearance for equivalent moles WT apoA-V and apoA-V Q252X recombinant protein (N=5). D. apoa5 KO mice expressing WT or Q252X apoA-V were administered 5μg WT or Q252X apoA-V synthetic HDL (rHDL). Percent initial TG over time. (N=5-6). E. Area under the curve (AUC) for mice shown in G. F. apoa5 KO mice were administered 20μg WT or Q252X apoA-V rHDL. Percent initial TG over time (N=7). G. AUC for mice shown in F. A-B. Points indicate single value. C-G. Mean with SEM (brackets). Unpaired 2-tailed t-test. p<0.001 = ***, p<0.0001 = **** vs. Buffer. p<0.05 = $, p<0.01 = $$, p<0.001 = $$$, p<0.0001 = $$$$ vs. WT. p<0.01 = ## vs. Q252X. apoA-I, apolipoprotein A-I; apoA-V, apolipoprotein A5; auc, area under the curve; DMPC, dimyristoyl phosphatidylcholine; FPLC, fast protein liquid chromatography; HDL, high-density lipoprotein; KO, knockout; LDL, low-density lipoprotein; rHDL, synthetic HDL with recombinant apoA-V protein; TG, triglyceride; VLDL, very low-density lipoprotein.