👤 Ruan Kruger

Although conventional lipids (high density lipoprotein cholesterol (HDLC), low density lipoprotein cholesterol (LDLC), total cholesterol (TC) and triglycerides (TG)) are therapeutic targets to manage and prevent atherosclerotic cardiovascular disease (CVD), apolipoprotein (Apo) levels have sparked interest for their potential to improve CVD risk prediction. This study explored the relationships of traditional CVD risk factors with conventional lipids, as well as ApoA1, ApoB and its ratio (ApoB: ApoA1) in South African adults of African ancestry. This study included 1697 adults (aged 29 to 94) from the Prospective Urban Rural Epidemiology (PURE) study. The CVD risk markers included body mass index (BMI), physical activity index, tobacco use, dietary fat intake, γ-glutamyl transferase (γGT) and glycated haemoglobin (HbA1C). Conventional lipids were measured in serum samples using standard methodology, while ApoA1 and ApoB were measured using a multiplex magnetic bead immunoassay. Stratified into tertiles of conventional lipid and Apo levels, trends emerged across multiple CVD risk markers, including BMI, tobacco use, fat intake, γGT and HbA1C levels. Higher tertiles of LDLC, TC, TG, ApoB and ApoB: ApoA1, along with the lowest tertiles of HDLC and ApoA1 exhibited higher prevalence of Type II diabetes mellitus (all p ≤ 0.024) and overweight or obesity (all except for TC, p ≤ 0.024). HDLC was negatively associated and LDLC, TC, and TG were positively associated with BMI (all p < 0.001) and HbA1C (all except for TC, p ≤ 0.005). Similarly, ApoA1 associated negatively with BMI (β=-0.067 (-0.125; -0.010), p = 0.022) and HbA1C (β=-0.071 (-0.122; -0.020), p = 0.007), while ApoB associated positively with BMI (β = 0.168 (0.117; 0.218), p < 0.001). The ApoB: ApoA1 showed positive associations with BMI (β = 0.213 (0.163; 0.263), p < 0.001) and HbA1C (β = 0.123 (0.074; 0.172), p < 0.001). In South African adults of African ancestry, ApoA1, ApoB and ApoB: ApoA1 levels are associated with various established CVD risk markers and suggests that these apolipoproteins may provide additional mechanistic insights beyond the conventional lipids to understand the aetiology of early cardiometabolic disease development. Show less

The placenta is a vital fetal organ that plays an important role in maintaining fetal sex hormone homeostasis. Xenobiotics can alter placental sex-steroidogenic enzymes and transporters, including enzymes such as aromatase (CYP19A1) and the hydroxysteroid dehydrogenases (HSDs) but studying how compounds disrupt in vivo placental metabolism is complex. Utilizing high-throughput in vitro models is critical to predict the disruption of placental sex-steroidogenic enzymes and transporters, particularly by drug candidates in the early stages of drug discovery. JAR and JEG-3 cells are the most common, simple, and cost-effective placental cell models that are capable of high-throughput screening, but how well they express the sex-steroidogenic enzymes and transporters is not well known. Here, we compared the proteomes of JAR and JEG-3 cells in the presence and absence of physiologically relevant concentrations of dehydroepiandrosterone (DHEA, 8 µM) and testosterone (15 nM) to aid the characterization of sex-steroidogenic enzymes and transporters in these cell models. Global proteomics analysis detected 2931 and 3449 proteins in JAR cells and JEG-3 cells, respectively. However, dramatic differences in sex-steroidogenic enzymes and transporters were observed between these cells. In particular, the basal expression of steroid sulfatase (STS), HSD17B1, and HSD17B7 were unique to JEG-3 cells. JEG-3 cells also showed significantly higher protein levels of aldo-keto reductase (AKR) 1A1 and AKR1B1, while JAR cells showed significantly higher levels of HSD17B4 and HSDB12. Aldehyde dehydrogenase (ALDH) 3A2 and HSD17B11 enzymes as well as the transporters sterol O-acyltransferase (SOAT) 1 and ATP binding cassette subfamily G2 (ABCG2) were comparable between the cell lines, whereas sulfotransferases (SULTs) were uniquely present within JAR cells. Androgen treatments significantly lowered HSD17B11, HSD17B4, HSD17B12, and ALDH3A2 levels in JAR cells. DHEA treatment significantly raised the level of HSD17B1 by 51 % in JEG-3 cells, whereas CYP19A1 was increased to significant levels in both JAR and JEG-3 cells after androgen treatments. The proteomics data were supported by a complementary targeted metabolomics analysis of culture media in the DHEA (8 µM) and testosterone (15 nM) treated groups. This study has indicated that untreated JEG-3 cells express more sex-steroidogenic enzymes and transporters. Nevertheless, JEG-3 and JAR cells are unique and their respective proteomics data can be used to select the best model depending on the hypothesis. Show less