👤 Salwa Afkir

The chimeric cytokine IC7Fc conveys the metabolic signaling properties of the glycoprotein 130 receptor cytokines interleukin-6 and ciliary neurotrophic factor via membrane-bound signaling. IC7Fc was previously shown to slow the progression of type 2 diabetes mellitus, and here, we demonstrate its effect on atherosclerotic development. In APOE*3-Leiden.CETP mice, an atherosclerosis-prone model with a humanized lipoprotein metabolism, IC7Fc markedly lowered plasma triglyceride and total cholesterol levels. This was mechanistically explained by an inhibition of de novo lipogenesis in the liver, increased synthesis of bile acids from cholesterol, and down-regulated apolipoprotein B synthesis, which resulted in decreased cholesterol secretion in very low-density lipoprotein particles. As a consequence, IC7Fc treatment considerably reduced atherosclerotic lesion formation and vascular inflammation compared with current antihyperlipidemic therapy. In conclusion, IC7Fc is a promising pharmacological treatment for cardiometabolic diseases targeting hyperlipidemia and inflammation. Show less

LIPC encodes hepatic lipase (HL), a liver-bound protein with both phospholipase and triglyceride lipase activity, and involved in the catabolism of circulating lipoproteins. We recently identified the gain-of-function variant HL-E97G, with selectively increased phospholipase activity, as a new genetic cause of familial combined hypocholesterolaemia in humans. The role of HL in the development of atherosclerosis remains controversial. In this context, the action of HL-E97G on the development of atherosclerosis remains unknown. To evaluate the lipid-lowering and anti-atherogenic properties of HL-E97G vs. wildtype HL (HL-WT) in hypercholesterolaemic APOE*3-Leiden.CETP mice, a well-established model for human-like lipoprotein metabolism, and to assess dependence of these effects on the LDL receptor (LDLR) pathway in LDLR-deficient (Ldlr-/-) mice. APOE*3.Leiden.CETP mice or Ldlr-/- mice received an intravenous injection of AAV8 expressing either eGFP (control), HL-WT or HL-E97G (3 × 1011 GC/mouse) while being fed pro-atherogenic diets. Plasma cholesterol levels were measured monthly, and aortic atherosclerotic lesion sizes were assessed at termination. HL-E97G largely decreased plasma total cholesterol exposure in APOE*3-Leiden.CETP mice (-63% vs. control; -58% vs. HL-WT), resulting at least in part from increased uptake of (V)LDL by the liver, accompanied by a marked decrease in atherosclerotic lesion size (-98% vs. control; -97% vs. HL-WT) in the aortic root. Importantly, HL-E97G also strongly reduced plasma cholesterol exposure in Ldlr-/- mice (-80% vs. control; -77% vs. HL-WT), and decreased atherosclerotic lesion size in the aortic root (-54% vs. control; -41% vs. HL-WT) and the aortic arch (-73% vs. control; -70% vs. HL-WT). HL-E97G strongly reduces plasma cholesterol levels, by increasing the uptake of (V)LDL, to decrease atherosclerosis development in mice independently of the LDLR pathway. These data suggest that modulating HL function is a promising tool in patients with familial hypercholesterolaemia. Show less

[D APOE*3-Leiden.CETP mice were treated with saline, acyl-ExD3 or acyl-ExF1 via intraperitoneal injections for 6 weeks or intracerebroventricular infusion for 18 days. Body weight and composition were monitored at regular intervals, as were plasma glucose, triglyceride and cholesterol levels. At endpoint, mice were injected with very low-density lipoprotein (VLDL)-like particles containing glycerol tri[ Upon peripheral treatment, body weight gain was prevented and plasma glucose levels were reduced by acyl-ExF1, but circulating lipids were not affected by either acyl-ExF1 or acyl-ExD3. In contrast, central administration of either agonist strongly reduced plasma triglyceride and cholesterol levels, but did not affect glucose levels. Acyl-ExD3 and acyl-ExF1 increased [ The oppositely biased GLP-1 receptor agonists acyl-ExD3 and acyl-ExF1 do not differentially affect lipid metabolism in APOE*3-Leiden.CETP mice, while effects on glucose homeostasis and prevention of body weight gain are more pronounced upon peripheral acyl-ExF1 treatment. Show less

Angiopoietin-like 3 (ANGPTL3) and 4 (ANGPTL4) inhibit lipoprotein lipase to regulate tissue fatty acid (FA) uptake from triglyceride (TG)-rich lipoproteins such as very low density lipoproteins (VLDL). While pharmacological inhibition of ANGPTL3 is being evaluated as a lipid-lowering strategy, systemic ANGPTL4 inhibition is not pursued due to adverse effects. This study aims to compare the therapeutic potential of liver-specific Angptl3 and Angptl4 silencing to attenuate hyperlipidemia and atherosclerosis development in APOE*3-Leiden.CETP mice, a well-established humanized model for lipoprotein metabolism. Mice were subcutaneously injected twice per week with saline or liver-targeted antisense oligonucleotides against Angptl3, Angptl4, both, or a scrambled oligonucleotide. Plasma lipid levels, VLDL clearance, and hepatic VLDL production were determined, and atherosclerosis development was assessed. For toxicological evaluation, cynomolgus monkeys were treated with three dosages of liver-targeted ANGPTL4-silencing oligonucleotides. Liver-targeted Angptl4 silencing reduced plasma TGs (-48%) and total cholesterol (-56%), explained by higher VLDL-derived FA uptake by brown adipose tissue and lower VLDL production by the liver. Accordingly, Angptl4 silencing reduced atherosclerotic lesion size (-86%) and improved lesion stability. Hepatic Angptl3 silencing similarly attenuated hyperlipidemia and atherosclerosis development. While Angptl3 and Angptl4 silencing lowered plasma TGs in the refed and fasted state, respectively, combined Angptl3/4 silencing lowered plasma TGs independent of the nutritional state. In cynomolgus monkeys, anti-ANGPTL4 ASO treatment was well tolerated without adverse effects. Liver-targeted Angptl4 silencing potently attenuates hyperlipidemia and atherosclerosis development in APOE*3-Leiden.CETP mice, and liver-targeted ANGPTL4 silencing is well tolerated in non-human primates. These data warrant further clinical development of liver-targeted ANGPTL4 silencing. Show less

Brown adipose tissue (BAT) contributes to cardiometabolic health by taking up glucose and lipids for oxidation, a process that displays a strong diurnal rhythm. While aging has been shown to reduce thermogenic characteristics of BAT, it is as yet unknown whether this reduction is specific to the time of day. Therefore, we assessed whole-body and BAT energy metabolism in young and middle-aged male and female C57BL/6J mice and studied the consequences for lipid metabolism in humanized APOE*3-Leiden.CETP mice (also on a C57BL/6J background). We demonstrate that in middle-aged versus young mice body temperature is lower in both male and female mice, while uptake of triglyceride (TG)-derived fatty acids (FAs) by BAT, reflecting metabolic activity, is attenuated at its peak at the onset of the dark (wakeful) phase in female mice. This coincided with delayed plasma clearance of TG-rich lipoproteins and TG-depleted lipoprotein core remnants, and elevated plasma TGs at the same time point. Furthermore, middle-aged female mice showed increased adiposity, accompanied by lipid accumulation, increased expression of genes involved in lipogenesis, and reduced expression of genes involved in fat oxidation and the intracellular clock machinery in BAT. Peak abundance of lipoprotein lipase (LPL), a crucial regulator of FA uptake, was attenuated in BAT. Our findings suggest that LPL is a potential therapeutic target for restoring diurnal metabolic BAT activity, and that efficiency of strategies targeting BAT may be improved by including time of day as an important factor. Show less