Arteriosclerosis, Thrombosis, and Vascular Biology最新文献

Background: Abnormal levels of VWF (von Willebrand Factor) are a risk factor for venous thromboembolism (VTE) and bleeding. Genome-wide association studies for VWF have identified novel candidate genes that may regulate VWF levels in humans, including RAB5C (RAS-associated protein RAB5C). We hypothesized that RAB5C regulates VWF release from endothelial cells.

Methods: We studied the effect of RAB5C on vesicle trafficking in human endothelial cells. We performed CRISPR (clustered regularly interspaced short palindromic repeats) interference targeting 2 genetic variants linked to altered VWF levels and evaluated RAB5C expression by reverse transcription-quantitative polymerase chain reaction. We silenced RAB5C or overexpressed RAB5C wild-type, constitutive active or dominant negative; and then, we measured VWF exocytosis from human umbilical vein endothelial cells to the media by ELISA. We performed proximity labeling and mass spectrometry to identify intracellular signaling pathways mediating the effects of RAB5C on VWF exocytosis.

Results: We found that 2 genetic variants (rs9915255 and rs9912088 identified by genome-wide association studies for VWF levels) regulate RAB5C expression in stem cell-derived endothelial cells. We next silenced or overexpressed RAB5C in endothelial cells to assess its effect on VWF release. RAB5C silencing decreased VWF release after histamine stimulation, whereas overexpression of RAB5C or constitutively active RAB5C increased endothelial VWF release. To explore the intracellular signaling pathway mediating the effects of RAB5C on VWF exocytosis, we performed proximity labeling and mass spectrometry. We identified 147 proteins proximal to RAB5C, many of which are involved in vesicle trafficking. From this screen, we identified SNAP29 (synaptosome-associated protein 29), a SNARE (soluble NSF attachment receptor)-associated protein that plays a crucial role in vesicle fusion, as a key RAB5C interactor regulating VWF exocytosis.

Conclusions: Taken together, our data demonstrate that RAB5C regulates VWF release in part through SNAP29 control of vesicle trafficking in endothelial cells. These findings validate genetic epidemiology data linking RAB5C to VWF levels in humans and provide new insights into the molecular mechanisms regulating VWF exocytosis.

Background: In Kawasaki disease (KD), coronary arteritis occurring in infancy can lead to long-term sequelae, such as luminal dilatation, stenosis, intimal thickening, and calcification. However, the long-term evolution of these lesions, particularly the effect of superimposed atherosclerosis in adulthood, remains poorly understood. This study aimed to investigate coronary artery lesions in adults with a history of KD and clarify the relationship between sequelae of vasculitis and atherosclerosis.

Methods: We analyzed 7 autopsy cases of sudden cardiac death in adults with a confirmed history of KD and documented coronary artery aneurysms. Clinical data, including acute-phase treatment history, body mass index, heart weight, coronary risk factors, and detailed coronary histopathology, were evaluated.

Results: All aneurysms were located at the coronary ostia and showed marked intimal thickening with severe calcification, leading to luminal narrowing. Thrombotic occlusion within the aneurysm was identified in 1 case. In 3 patients aged older than 30 years, atherosclerotic changes were observed in the thickened intima of persistent aneurysmal segments or dilated portions. One patient with a regressed aneurysm died of acute myocardial infarction caused by plaque rupture. Sequelae of vasculitis were widely distributed in nonaneurysmal coronary branches, and atherosclerotic changes were also noted in these regions.

Conclusions: In adults with persistent coronary aneurysms due to KD, atherosclerotic lesions may develop not only in aneurysmal segments but also in nondilated arteries with scarring due to vasculitis. Individuals with prior KD and coronary aneurysms may require long-term management for thrombotic risk and the prevention of atherosclerosis, beginning in early adulthood.

Arterial dilation can lead to aneurysm formation, most commonly affecting the aorta and intracranial arteries. Platelets are now recognized as key mediators of vascular inflammation and remodeling, contributing to the initiation and progression of several vascular diseases. While the role of platelets in abdominal aortic aneurysm formation has gained considerable attention and is under active investigation, their contribution to intracranial aneurysm pathophysiology remains poorly understood. In this review, we summarize current mechanistic and preclinical evidence on the development and rupture of intracranial aneurysms. We discuss how platelet interactions with leukocytes, vascular cells, and their procoagulant role may influence inflammatory and tissue damage within the intracranial aneurysm, highlighting gaps in knowledge that could reveal new mechanisms.

Background: Antithrombin resistance (ATR) is a congenital thrombotic predisposition caused by abnormal prothrombin (FII). Abnormal FII with ATR characteristics, when converted to thrombin (FIIa), shows a reduced affinity of binding to AT, resulting in reduced anti-FIIa and a thrombotic tendency. Data on the efficacy of anticoagulants in ATR are currently insufficient.

Methods: Mouse models of ATR were generated to investigate the efficacy of anticoagulants. Because FII R596L, which causes ATR in humans, was considered to correspond to R593L in mice based on gene sequence analysis, knock-in mice that systemically express FII R593L were generated. First, the nature of ATR was confirmed by blood coagulation analysis. We then evaluated thrombotic tendency at the individual level using an inferior vena cava stenosis model, and evaluated the antithrombotic effects of unfractionated heparin, low molecular weight heparin, synthetic pentasaccharide, and direct oral anticoagulants.

Results: In coagulation studies, R593L Homo and Hetero mice (R593L Homo and Hetero, respectively) exhibited lower FII antigen levels and lower FIIa generation potential than wild-type mice, but residual FIIa activity after addition of AT confirmed the presence of ATR properties. In the inferior vena cava stenosis model, significantly higher thrombus formation was maintained in R593L Homo and Hetero compared with wild-type, even 96 hours after inferior vena cava stenosis. In anticoagulant administration experiments, anticoagulants with anti-FIIa effects appeared more effective against FII R593L.

Conclusions: Knock-in of FII R593L produced ATR model mice, which showed a strong thrombotic tendency. Evaluation of antithrombotic therapies showed that anticoagulants with anti-FIIa effects were highly effective.

Enhancers are regulatory DNA sequences that increase the transcription of a target gene when bound by transcription factors. Decades of research endeavors have shed light on the crucial roles of enhancers in cardiovascular development and disease. Besides working as cis-regulatory elements, enhancers also play critical roles in transactivating mechanisms such as enhancer RNA transcription and transcriptional condensates. Technological advances, such as single-cell multiomics, CRISPR (clustered regularly interspaced short palindromic repeats)-based enhancer perturbation screens, and machine learning technologies, provide us with unprecedented opportunities to gain novel insights into the dynamic function of cardiovascular enhancers. In this brief review, we discuss cutting-edge techniques that are being or can be leveraged to fill knowledge gaps in studying cardiovascular enhancers. Like gene expression, enhancers display functional dynamics in concordance with specific cellular stress. We summarize the findings of inducible enhancer functions in the cardiovascular system. We also discuss several recent studies that are advancing our understanding of cardiovascular enhancer functions and are potentially paradigm-shifting. These insights have great potential to inform novel therapeutic strategies targeting enhancer-mediated gene dysregulation in cardiovascular disease.

Background: Marfan syndrome is an inherited disorder caused by FBN1 gene mutations, which can lead to thoracic aortic aneurysm and dissection. Selective AT₁ (angiotensin II type 1) receptor blockade is a preventive option against Marfan syndrome aortopathy, and recent clinical studies demonstrated that the inhibitory effect of an ARB (AT₁ receptor blocker) losartan on aortic aneurysm growth is equivalent to that of β-blockers. At present, several ARBs are clinically available, and they have drug-specific differences in pharmacological properties. Especially, inverse agonism of ARBs has potential benefits for cardiovascular protection, but its impact on Marfan syndrome aortopathy remains poorly understood.

Methods: Candesartan-7H is a candesartan derivative that lacks the carboxyl group critical for inverse agonist activity and works as a neutral antagonist for the AT₁ receptor. Candesartan cilexetil (1 mg/kg per day), candesartan-7H (1 or 20 mg/kg per day), or vehicle was administered to Fbn1^C1041G/+ mice, and aortic dilatation was analyzed using echocardiography, histological staining, and in situ MMP (matrix metalloproteinase) assay. Activation of TGF-β (transforming growth factor β) signaling and mechanosensitive signaling was studied using Western blot and immunohistochemical analysis.

Results: Candesartan cilexetil (1 mg/kg per day) and candesartan-7H (20 mg/kg per day) lowered blood pressures equally in Fbn1^C1041G/+ mice. Progressive dilatation of the aorta in association with aortic wall thickening, degeneration of elastic fibers, deposition of collagen, MMP activation, and TGF-β signaling activation in Fbn1^C1041G/+ mice was significantly suppressed by treatment with candesartan cilexetil (1 mg/kg per day), but not by candesartan-7H, even at 20 mg/kg per day. In addition, candesartan cilexetil, but not candesartan-7H, suppressed activation of mechanosensitive signaling involving focal adhesion kinase, p38 mitogen-activated protein kinase, and early growth response-1 in the ascending aorta of Fbn1^C1041G/+ mice.

Conclusions: Our findings support a crucial role of inverse agonist activity of ARB for the prevention of mechanical stress-induced AT₁ receptor activation and aortic aneurysm progression in Marfan syndrome mice.

Despite a growing therapeutic arsenal, atherosclerotic cardiovascular disease remains the major cause of mortality worldwide. Hepatic lipase, encoded by the gene LIPC (lipase C, hepatic type), is a protein that has recently regained interest in this context. In this review, we provide a comprehensive overview of the versatile roles of hepatic lipase in lipoprotein metabolism, with a focus on the recently discovered LIPC-E97G (point mutation replacing glutamic acid with glycine at position 97) variant. Specifically, we discuss the roles of hepatic lipase in the metabolism of high-density lipoproteins and apoB-containing lipoproteins, as elucidated through in vitro, in vivo, and genetic studies. We also explore the complex interplay between the antiatherogenic and proatherogenic effects of hepatic lipase, highlighting a predominance of antiatherogenic functions for hepatic lipase. Lastly, we briefly discuss how the knowledge on the function of hepatic lipase can potentially be harnessed for the treatment of atherosclerotic cardiovascular disease.

Sex and reproductive history are established nontraditional risk factors for cardiovascular disease, but their relevance for peripheral artery disease (PAD) remains unclear. This narrative review examines the current evidence surrounding underlying mechanisms and associations between female sex, reproductive factors, and the development of atherosclerosis, focusing on PAD specifically. Overall, there is a paucity of evidence regarding the association between sex-specific risk factors and PAD. However, hypertensive disorders of pregnancy, gestational diabetes, and adverse pregnancy outcomes are significantly associated with increased incident PAD. Further work is needed to improve the mechanistic understanding of associations between sex-specific risk factors and PAD. In addition, increased clinician awareness may facilitate earlier risk factor detection and preventative strategies. In future, integrating reproductive history into cardiovascular risk assessment may enable more personalized care and ultimately reduce PAD burden among women.

Background: RIPK3 (receptor-interacting protein kinase 3) has context-specific roles that are frequently associated with cellular damage and death. We previously found that hypoxia can trigger elevated levels of RIPK3 in endothelial cells (ECs), which contributes to lethal vascular rupture during mouse embryonic development. However, it is unknown whether elevated RIPK3 likewise compromises endothelial barrier function in adult vasculature under hypoxic conditions such as ischemia-reperfusion (I/R) injury.

Methods: Twelve-week-old male and female littermate control or inducible EC-specific Ripk3 knockout (Ripk3^iECKO) mice were exposed to surgical intestinal I/R injury. Clodronate liposomes were used to reduce circulating monocytes in vivo. Immortalized murine EC (MS1 [mile sven 1) and murine macrophage (BMA3.1A7 [bone marrow A clone 3.187]) lines were used for in vitro experiments.

Results: Ripk3^iECKO mice displayed an unexpected increase in small intestinal vascular permeability after I/R injury, rather than the decrease we predicted. Subsequent analyses using multiplex cytokine assays revealed significantly elevated levels of IL-6 (interleukin-6) in the serum and small intestinal tissue of I/R-injured Ripk3^iECKO mice. Upon TNFα (tumor necrosis factor-alpha) stimulation of immortalized murine Ripk3 knockout ECs grown in vitro, we found increased transcription and secretion of IL-6. These cells also expressed elevated levels of VCAM-1 (vascular cell adhesion molecule-1), which was likewise upregulated in the small intestines of Ripk3^iECKO mice. Using an IL-6 neutralizing antibody, we found that IL-6 triggered VCAM-1 elevation in Ripk3 knockout cells. This VCAM-1 expression correlated with enhanced macrophage binding to Ripk3 knockout cells and increased accumulation of leukocytes in Ripk3^iECKO small intestines following I/R injury. Importantly, reduction of circulating monocytes with clodronate liposomes led to rescue of IR injury-induced vascular permeability in Ripk3^iECKO mice.

Conclusions: Endothelial RIPK3 suppresses EC activation and inflammation associated with IL-6 and VCAM-1 elevation to protect the vascular barrier in the context of intestinal I/R injury. Thus, endothelial RIPK3 plays surprisingly beneficial roles that reduce I/R injury-induced vascular dysfunction.