Aims Lipoprotein(a) [Lp(a)] is elevated in 20–30% of people. This study aimed to assess the effect of statins on Lp(a) levels. Methods and results This subject-level meta-analysis includes 5256 patients (1371 on placebo and 3885 on statin) from six randomized trials, three statin-vs.-placebo trials, and three statin-vs.-statin trials, with pre- and on-treatment (4–104 weeks) Lp(a) levels. Statins included atorvastatin 10 mg/day and 80 mg/day, pravastatin 40 mg/day, rosuvastatin 40 mg/day, and pitavastatin 2 mg/day. Lipoprotein(a) levels were measured with the same validated assay. The primary analysis of Lp(a) is based on the log-transformed data. In the statin-vs.-placebo pooled analysis, the ratio of geometric means [95% confidence interval (CI)] for statin to placebo is 1.11 (1.07–1.14) (P < 0.0001), with ratio >1 indicating a higher increase in Lp(a) from baseline in statin vs. placebo. The mean percent change from baseline ranged from 8.5% to 19.6% in the statin groups and −0.4% to −2.3% in the placebo groups. In the statin-vs.-statin pooled analysis, the ratio of geometric means (95% CI) for atorvastatin to pravastatin is 1.09 (1.05–1.14) (P < 0.0001). The mean percent change from baseline ranged from 11.6% to 20.4% in the pravastatin group and 18.7% to 24.2% in the atorvastatin group. Incubation of HepG2 hepatocytes with atorvastatin showed an increase in expression of LPA mRNA and apolipoprotein(a) protein. Conclusion This meta-analysis reveals that statins significantly increase plasma Lp(a) levels. Elevations of Lp(a) post-statin therapy should be studied for effects on residual cardiovascular risk.

Supplementary key words lipid metabolism • apolipoprotein C-III • apolipoprotein E • triglyceride-rich lipoprotein clearance • fatty acids • lipase • lipoprotein lipase Elevated plasma triglyceride (TG) levels are an independent risk factor for CVD and all-cause mortality (1). The concentration of plasma TG levels reflects a balance between de novo synthesis in the liver (VLDLs), intestinal absorption of dietary lipids (chylomicrons), lipolysis in the peripheral circulation, and hepatic clearance. TG-rich lipoproteins (TRLs) carry TGs in the blood and are rapidly hydrolyzed by LPL, thereby releasing free FAs for energy production or storage in the surrounding tissues (2-4). The remnant TRLs are subsequently rapidly cleared in the liver by the interaction of apolipoproteins on TRLs with the three main hepatic receptors, heparan sulfate proteoglycan syndecan-1 (SDC1), LDL receptor (LDLR), and LDLR-related protein 1 (LRP1) (5). TRLs carry several apolipoproteins, including apoB, apoE, apoAV, and apoC-III. ApoB and apoE serve as ligands for LDLR and LRP1, promoting hepatic TLR clearance (6-10). In contrast, hepatic SDC1 recognizes apoE and apoAV, dependent on the interaction of these apolipoproteins with the heparan sulfate side chains on SDC1 (9). Human apoE is a 299 amino acid polymorphic glycoprotein Abstract Hypertriglyceridemia results from accumulation of triglyceride (TG)-rich lipoproteins (TRLs) in the circulation and is associated with increased CVD risk. ApoC-III is an apolipoprotein on TRLs and a prominent negative regulator of TG catabolism. We recently established that in vivo apoC-III predominantly inhibits LDL receptor-mediated and LDL receptor-related protein 1-mediated hepatic TRL clearance and that apoC-III-enriched TRLs are preferentially cleared by syndecan-1 (SDC1). In this study, we determined the impact of apoE, a common ligand for all three receptors, on apoC-III metabolism using apoC-III antisense oligonucleotide (ASO) treatment in mice lacking apoE and functional SDC1 (Apoe / Ndst1 f/f Alb-Cre +). ApoC-III ASO treatment significantly reduced plasma TG levels in Apoe / Ndst1 f/f Alb-Cre + mice without reducing hepatic VLDL production or improving hepatic TRL clearance. Further analysis revealed that apoC-III ASO treatment lowered plasma TGs in Apoe / Ndst1 f/f Alb-Cre + mice, which was associated with increased LPL activity in white adipose tissue in the fed state. Finally, clinical data confirmed that ASO-mediated lowering of APOC-III via volanesorsen can reduce plasma TG levels independent of the APOE isoform genotype. Our data indicate that apoE determines the metabolic impact of apoC-III as we establish that apoE is essential to mediate inhibition of TRL clearance by apoC-III and that, in the absence of functional apoE, apoC-III inhibits tissue LPL activity.-Ramms, B.

We identify the prolyl-tRNA synthetase (PRS) inhibitor halofuginone, a compound in clinical trials for anti-fibrotic and anti-inflammatory applications, as a potent inhibitor of SARS-CoV-2 infection and replication. The interaction of SARS-CoV-2 spike protein with cell surface heparan sulfate (HS) promotes viral entry. We find that halofuginone reduces HS biosynthesis, thereby reducing spike protein binding, SARS-CoV-2 pseudotyped virus, and authentic SARS-CoV-2 infection. Halofuginone also potently suppresses SARS-CoV-2 replication post-entry. Utilizing analogues of halofuginone and small molecule inhibitors of the PRS, we establish that inhibition of HS presentation and viral replication is dependent on proline tRNA synthesis opposed to PRS activation of the integrated stress response (ISR). Moreover, we provide evidence that these effects are mediated by the depletion of proline tRNAs. In line with this, we find that SARS-CoV-2 polyproteins, as well as several HS proteoglycans, are particularly proline-rich, which may make them vulnerable to halofuginone translational suppression. Halofuginone is orally bioavailable, has been evaluated in a phase I clinical trial in humans and distributes to SARS-CoV-2 target organs, including the lung, making it a promising clinical trial candidate for the treatment of COVID-19.

Heparan Sulfate (HS) is a cell signaling molecule linked to pathological processes ranging from cancer to viral entry, yet fundamental aspects of its biosynthesis remain incompletely understood. Here, the binding preferences of the uronyl 2-O-sulfotransferase (HS2ST) are examined with variably-sulfated hexasaccharides. Surprisingly, heavily sulfated oligosaccharides formed by later-acting sulfotransferases bind more tightly to HS2ST than those corresponding to its natural substrate or product. Inhibition assays also indicate that the IC50 values correlate simply with degree of oligosaccharide sulfation. Structural analysis predicts a mode of inhibition in which 6-O-sulfate groups located on glucosamine residues present in highly-sulfated oligosaccharides occupy the canonical binding site of the nucleotide cofactor. The unexpected finding that oligosaccharides associated with later stages in HS biosynthesis inhibit HS2ST indicates that the enzyme must be separated temporally and/or spatially from downstream products during biosynthesis in vivo, and highlights a challenge for the enzymatic synthesis of lengthy HS chains in vitro.

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