👤 Alan Daugherty

The comparative roles of triglyceride-rich lipoproteins (TRLs) and low-density lipoproteins (LDLs) in abdominal aortic aneurysm (AAA) pathogenesis are unclear. To evaluate the putative causal role of TRLs in AAA, quantify the relative effect on AAA risk ("aneurysmogenicity") of TRL vs LDL particles, and prioritize lipid-lowering drug targets for AAA prevention and treatment. We performed summary-level and individual-level Mendelian randomization (MR) analyses. Genetic variants were selected from 383,983 UK Biobank participants and ranked into 10 sets of variants where set 1 predominantly affected LDL cholesterol (LDL-C) and set 10 predominantly affected TRL cholesterol (TRL-C; and with mixed effects for intermediate variant sets). AAA outcome data were obtained from AAAgen (37,214 cases), FinnGen (4,439 cases), and the VA Million Veteran Program (MVP; 23,848 cases). Multivariable MR was used to assess the independent roles of LDL-C and TRL-C in AAA. For each set of variants, MR or logistic regression was used to estimate AAA odds ratios (ORs) per 10 mg/dL higher apolipoprotein B (apoB). Interaction analyses were conducted between a statin-like LDL-C-lowering variant set (set 3) and a TRL-C-lowering variant set (set 10). Drug-target MR was performed to evaluate lipid-lowering targets relevant to LDL-C- and TRL-C-lowering. Genetically predicted LDL-C and TRL-C concentrations were each associated independently with genetic liability for AAA after mutual adjustment, with 3.0 to 5.5 times stronger associations for TRL-C compared to LDL-C on a per-cholesterol basis. In AAAgen, the AAA OR per 10 mg/dL increased apoB concentrations were 1.10 (95% CI, 1.05-1.14) for variant set 1 (LDL-C-predominant) and 1.89 (95% CI, 1.69-2.11) for variant set 10 (TRL-C-predominant). Using the ratio of log(OR) per 10 mg/dL apoB for set 10 versus set 1 as a conservative estimate of relative aneurysmogenicity, TRLs were approximately 3.2 to 6.9 times more aneurysmogenic than LDLs across the three studies. No evidence of interaction was observed between LDLs and TRLs, indicating additive contribution to AAA risk. Drug-target MR supported strong protective associations for genetically proxied inhibition of TRL-pathway targets, particularly TRLs are at least threefold more aneurysmogenic than LDLs on a per-particle basis. Therapeutic strategies targeting TRL-C -especially via Show less

Abdominal aortic aneurysm (AAA) is a life-threatening vascular disease with no effective pharmacological treatments. The causal role of triglycerides (TGs) in AAA development remains unclear and controversial. Mendelian randomization was applied to assess causal relationships between lipoproteins, circulating proteins, metabolites, and the risk of AAA. To test the hypothesis that elevated plasma TG levels accelerate AAA development, we used Mendelian randomization analyses integrating genetic, proteomic, and metabolomic data identified causal relationships between elevated TG-rich lipoproteins, TG metabolism-related proteins/metabolites, and AAA risk. In the angiotensin II infusion AAA model, most These findings identify hypertriglyceridemia as a key contributor to AAA pathogenesis and suggest that targeting TG-rich lipoproteins may be a promising therapeutic strategy for AAA. Show less

Abdominal aortic aneurysm (AAA) is a life-threatening vascular disease without effective medications. This study integrated genetic, proteomic, and metabolomic data to identify causation between increased triglyceride (TG)-rich lipoproteins and AAA risk. Three hypertriglyceridemia mouse models were employed to test the hypothesis that increased plasma TG concentrations accelerate AAA development and rupture. In the angiotensin II-infusion AAA model, most Show less

Metformin, a biguanide antihyperglycemic agent, prevents angiotensin II (AngII)-induced abdominal aortic aneurysm formation in apolipoprotein E-deficient (ApoE-/-) mice. Low-density lipoprotein receptor-deficient (LDLR-/-) mice, a commonly used hypercholesterolemic model, closely mimics the lipoprotein distribution in humans. In addition, LDLR-/- mice exhibit characteristics of glucose metabolism that are distinct from ApoE-/- mice. However, it remains unknown whether metformin suppresses AngII-induced aortic aneurysm formation in LDLR-/- mice. Male LDLR-/- mice at 9 weeks of age were administered either vehicle or metformin in drinking water and fed a Western diet. Subsequently, AngII was infused into mice for 4 weeks. Mass spectrometry analysis determined plasma metformin concentrations in mice administered the drug. Metformin administration resulted in lower body weight compared to the vehicle group, indicating effective metformin administration. However, ex vivo measurements demonstrated that metformin failed to prevent AngII-induced ascending aortic dilatations, and did not reduce aortic diameters in the suprarenal abdominal region. In conclusion, metformin did not attenuate AngII-induced aortic aneurysm formation in either the ascending or suprarenal abdominal region of LDLR-/- mice. The online version contains supplementary material available at 10.1038/s41598-025-33367-y. Show less

Protein phosphatase 6 (PP6) is an essential Ser/Thr phosphatase conserved among eukaryotes. The Saccharomyces cerevisiae homologue of PP6 called Sit4 depends on association with SAPS domain subunits. This study used a human SAPS domain subunit FLAG-PP6R1 to identify endogenous interacting proteins. Mass spectrometry identified coprecipitating proteins as PP6 catalytic subunit and three ankyrin repeat proteins (Ankrd28, Ankrd44, and Ankrd52). These proteins have extensive sequence identity to one another but segregate into separate branches on a phylogenetic tree for vertebrate species, suggesting individual biological functions. Tagged Ankrd28 coprecipitated with PP6, not with PP2A or PP4, and with SAPS domain subunits PP6R1 and PP6R3. Tagged PP6 coprecipitated endogenous SAPS domain subunits and Ankrd28. The C-terminal region of PP6R1 was sufficient to coprecipitate Ankrd28, but not PP6, demonstrating that PP6R1 acts as a scaffold with separate regions for binding to PP6 and to Ankrd28. Endogenous PP6 holoenzymes with PP6R1 and PP6R3 subunits were resolved by DEAE chromatography and eluted together with Ankrd28 at Mr > 440 kDa from Superose 12. Knockdown of PP6R1 or Ankrd28, but not PP6R3, produced equivalent enhancement of IkappaBepsilon degradation in response to TNFalpha. The results suggest that PP6 functions as a heterotrimer, composed of the PP6 catalytic subunit bound to a SAPS domain scaffold subunit that associates with Ankrd28. We propose that the SAPS and ankyrin repeat regulatory subunits determine the function and specificity of PP6. Show less