Epsin-mediated degradation of IP3R1 fuels atherosclerosis

Exploring the Mechanism of Fufang Danshen Tablet against Atherosclerosis by Network Pharmacology and Experimental Validation

Atherosclerosis is the main pathological basis of cardiovascular diseases (CVDs). Fufang Danshen Tablet (FDT) is a traditional Chinese medicine that has been clinically used to treat CVDs for more than 40 years. Nevertheless, owing to the complexity of the ingredients, the pharmacological mechanism of FDT in the treatment of CVDs has not been fully elucidated. In this study, an integrated strategy of UFLC-Q-TOF-MS/MS, network pharmacology, molecular biology, and transcriptomics was used to elucidate the mechanisms of action of FDT in the treatment of atherosclerosis. In total, 22 absorbed constituents were identified in rat serum after oral administration of FDT. In silico, network pharmacology studies have shown that FDT regulates four key biological functional modules for the treatment of atherosclerosis: oxidative stress, cell apoptosis, energy metabolism, and immune/inflammation. In animal experiments, FDT exerted protective effects against atherosclerosis by reducing the plaque area and lipid levels in ApoE-/- mice. Furthermore, we found that FDT inhibited inflammatory macrophage accumulation by regulating the expression of Selp and Ccl2, which are both involved in monocyte adhesion and migration. The inhibition of monocyte recruitment by FDT is a new perspective to elucidate the anti-atherosclerotic mechanism of FDT, which has not been adopted in previous studies on FDT. Our results may help to elucidate the therapeutic mechanism of FDT against CVDs and provide potential therapeutic targets.

Epsin Endocytic Adaptor Proteins in Angiogenic and Lymphangiogenic Signaling

Circulating vascular endothelial growth factor (VEGF) ligands and receptors are central regulators of vasculogenesis, angiogenesis, and lymphangiogenesis. In response to VEGF ligand binding, VEGF receptor tyrosine kinases initiate the chain of events that transduce extracellular signals into endothelial cell responses such as survival, proliferation, and migration. These events are controlled by intricate cellular processes that include the regulation of gene expression at multiple levels, interactions of numerous proteins, and intracellular trafficking of receptor-ligand complexes. Endocytic uptake and transport of macromolecular complexes through the endosome-lysosome system helps fine-tune endothelial cell responses to VEGF signals. Clathrin-dependent endocytosis remains the best understood means of macromolecular entry into cells, although the importance of non-clathrin-dependent pathways is increasingly recognized. Many of these endocytic events rely on adaptor proteins that coordinate internalization of activated cell-surface receptors. In the endothelium of both blood and lymphatic vessels, epsins 1 and 2 are functionally redundant adaptors involved in receptor endocytosis and intracellular sorting. These proteins are capable of binding both lipids and proteins and are important for promoting curvature of the plasma membrane as well as binding ubiquitinated cargo. Here, we discuss the role of epsin proteins and other endocytic adaptors in governing VEGF signaling in angiogenesis and lymphangiogenesis and discuss their therapeutic potential as molecular targets.

A mini review on selenium quantum dots: synthesis and biomedical applications

In recent years, the demand for advanced biomedical nanomaterials has seen a noticeable surge. Among the essential trace elements in the human body, selenium has gained recognition for its anti-cancer, antioxidant, and immune regulatory properties. However, traditional selenium-based semiconductor quantum dots (QDs) are often comprised of heavy metal elements that tend to be toxic, thereby limiting their usage in biomedical applications. Fortunately, the advent of elemental selenium quantum dots (SeQDs), a new kind of fluorescent nanomaterial with unique physicochemical properties, has provided a solution to this problem. These SeQDs are known for their low toxicity and good biocompatibility, making them a promising candidate for biomedical applications. In this mini-review, we delve into the synthesis methods of fluorescent SeQDs and the latest progress in their applications in bioimaging, biosensing, and diagnosis treatment. Finally, we identify the major challenges and future prospects in the field of SeQDs.

Non-canonical STING-PERK pathway dependent epigenetic regulation of vascular endothelial dysfunction via integrating IRF3 and NF-κB in inflammatory response

Inflammation-driven endothelial dysfunction is the major initiating factor in atherosclerosis, while the underlying mechanism remains elusive. Here, we report that the non-canonical stimulator of interferon genes (STING)-PKR-like ER kinase (PERK) pathway was significantly activated in both human and mice atherosclerotic arteries. Typically, STING activation leads to the activation of interferon regulatory factor 3 (IRF3) and nuclear factor-kappa B (NF-κB)/p65, thereby facilitating IFN signals and inflammation. In contrast, our study reveals the activated non-canonical STING-PERK pathway increases scaffold protein bromodomain protein 4 (BRD4) expression, which encourages the formation of super-enhancers on the proximal promoter regions of the proinflammatory cytokines, thereby enabling the transactivation of these cytokines by integrating activated IRF3 and NF-κB via a condensation process. Endothelium-specific STING and BRD4 deficiency significantly decreased the plaque area and inflammation. Mechanistically, this pathway is triggered by leaked mitochondrial DNA (mtDNA) via mitochondrial permeability transition pore (mPTP), formed by voltage-dependent anion channel 1 (VDAC1) oligomer interaction with oxidized mtDNA upon cholesterol oxidation stimulation. Especially, compared to macrophages, endothelial STING activation plays a more pronounced role in atherosclerosis. We propose a non-canonical STING-PERK pathway-dependent epigenetic paradigm in atherosclerosis that integrates IRF3, NF-κB and BRD4 in inflammatory responses, which provides emerging therapeutic modalities for vascular endothelial dysfunction.

Steady-state regulation of COPII-dependent secretory cargo sorting by inositol trisphosphate receptors, calcium, and penta EF hand proteins

Recently, we demonstrated that agonist-stimulated Ca2+ signaling involving IP3 receptors modulates ER export rates through activation of the penta-EF Hand proteins apoptosis-linked gene-2 (ALG-2) and peflin. It is unknown, however, whether IP3Rs and penta-EF proteins regulate ER export rates at steady state. Here we tested this idea in normal rat kidney epithelial cells by manipulation of IP3R isoform expression. Under standard growth conditions, spontaneous cytosolic Ca2+ oscillations occurred simultaneously in successive groups of contiguous cells, generating intercellular Ca2+ waves that moved across the monolayer periodically. Depletion of IP3R-3, typically the least promiscuous IP3R isoform, caused increased cell participation in intercellular Ca2+ waves in unstimulated cells. The increased spontaneous signaling was sufficient to cause increased ALG-2 and COPII coat subunit Sec31A and decreased peflin localization at ER exit sites, resulting in increased ER-to-Golgi transport of the COPII client cargo VSV-G. The elevated ER-to-Golgi transport caused greater concentration of VSV-G at ER exit sites and had reciprocal effects on transport of VSV-G and a bulk-flow cargo, though both cargos equally required Sec31A. Inactivation of client cargo sorting using 4-phenylbutyrate had opposing reciprocal effects on client and bulk-flow cargo and neutralized any effect of ALG-2 activation on transport. This work extends our knowledge of ALG-2 mechanisms and indicates that in normal rat kidney cells, IP3R isoforms regulate homeostatic Ca2+ signaling that helps determine the basal secretion rate and stringency of COPII-dependent cargo sorting.

Research progress on post-translational modification of proteins and cardiovascular diseases

Cardiovascular diseases (CVDs) such as atherosclerosis, myocardial remodeling, myocardial ischemia-reperfusion (I/R) injury, heart failure, and oxidative stress are among the greatest threats to human health worldwide. Cardiovascular pathogenesis has been studied for decades, and the influence of epigenetic changes on CVDs has been extensively studied. Post-translational modifications (PTMs), including phosphorylation, glycosylation, methylation, acetylation, ubiquitination, ubiquitin-like and nitrification, play important roles in the normal functioning of the cardiovascular system. Over the past decade, with the application of high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), an increasing number novel acylation modifications have been discovered, including propionylation, crotonylation, butyrylation, succinylation, lactylation, and isonicotinylation. Each change in protein conformation has the potential to alter protein function and lead to CVDs, and this process is usually reversible. This article summarizes the mechanisms underlying several common PTMs involved in the occurrence and development of CVDs.

Epsin1-mediated exosomal sorting of Dll4 modulates the tubular-macrophage crosstalk in diabetic nephropathy

Tubular epithelial cells (TECs) play critical roles in the development of diabetic nephropathy (DN), and can activate macrophages through the secretion of exosomes. However, the mechanism(s) of TEC-exosomes in macrophage activation under DN remains unknown. By mass spectrometry, 1,644 differentially expressed proteins, especially Dll4, were detected in the urine exosomes of DN patients compared with controls, which was confirmed by western blot assay. Elevated Epsin1 and Dll4/N1ICD expression was observed in kidney tissues in both DN patients and db/db mice and was positively associated with tubulointerstitial damage. Exosomes from high glucose (HG)-treated tubular cells (HK-2) with Epsin1 knockdown (KD) ameliorated macrophage activation, TNF-α, and IL-6 expression, and tubulointerstitial damage in C57BL/6 mice in vivo. In an in vitro study, enriched Dll4 was confirmed in HK-2 cells stimulated with HG, which was captured by THP-1 cells and promoted M1 macrophage activation. In addition, Epsin1 modulated the content of Dll4 in TEC-exosomes stimulated with HG. TEC-exosomes with Epsin1-KD significantly inhibited N1ICD activation and iNOS expression in THP-1 cells compared with incubation with HG alone. These findings suggested that Epsin1 could modulate tubular-macrophage crosstalk in DN by mediating exosomal sorting of Dll4 and Notch1 activation.

Non-inositol 1,4,5-trisphosphate (IP3) receptor IP3-binding proteins

Conventionally, myo-D-inositol 1, 4,5-trisphosphate (IP₃) is thought to exert its second messenger effects through the gating of IP₃R Ca²⁺ release channels, located in Ca²⁺-storage organelles like the endoplasmic reticulum. However, there is considerable indirect evidence to support the concept that IP₃ might interact with other, non-IP₃R proteins within cells. To explore this possibility further, the Protein Data Bank was searched using the term "IP3". This resulted in the retrieval of 203 protein structures, the majority of which were members of the IP₃R/ryanodine receptor superfamily of channels. Only 49 of these structures were complexed with IP₃. These were inspected for their ability to interact with the carbon-1 phosphate of IP₃, since this is the least accessible phosphate group of its precursor, phosphatidylinositol 4,5-bisphosphate (PI(4,5)P₂). This reduced the number of structures retrieved to 35, of which 9 were IP₃Rs. The remaining 26 structures represent a diverse range of proteins, including inositol-lipid metabolizing enzymes, signal transducers, PH domain containing proteins, cytoskeletal anchor proteins, the TRPV4 ion channel, a retroviral Gag protein and fibroblast growth factor 2. Such proteins may impact on IP₃ signalling and its effects on cell-biology. This represents an area open for exploration in the field of IP₃ signalling.

Targeting Epsins to Inhibit Fibroblast Growth Factor Signaling While Potentiating Transforming Growth Factor-β Signaling Constrains Endothelial-to-Mesenchymal Transition in Atherosclerosis

BACKGROUND

Epsin endocytic adaptor proteins are implicated in the progression of atherosclerosis; however, the underlying molecular mechanisms have not yet been fully defined. In this study, we determined how epsins enhance endothelial-to-mesenchymal transition (EndoMT) in atherosclerosis and assessed the efficacy of a therapeutic peptide in a preclinical model of this disease.

METHODS

Using single-cell RNA sequencing combined with molecular, cellular, and biochemical analyses, we investigated the role of epsins in stimulating EndoMT using knockout in Apoe-/- and lineage tracing/proprotein convertase subtilisin/kexin type 9 serine protease mutant viral-induced atherosclerotic mouse models. The therapeutic efficacy of a synthetic peptide targeting atherosclerotic plaques was then assessed in Apoe-/- mice.

RESULTS

Single-cell RNA sequencing and lineage tracing revealed that epsins 1 and 2 promote EndoMT and that the loss of endothelial epsins inhibits EndoMT marker expression and transforming growth factor-β signaling in vitro and in atherosclerotic mice, which is associated with smaller lesions in the Apoe-/- mouse model. Mechanistically, the loss of endothelial cell epsins results in increased fibroblast growth factor receptor-1 expression, which inhibits transforming growth factor-β signaling and EndoMT. Epsins directly bind ubiquitinated fibroblast growth factor receptor-1 through their ubiquitin-interacting motif, which results in endocytosis and degradation of this receptor complex. Consequently, administration of a synthetic ubiquitin-interacting motif-containing peptide atheroma ubiquitin-interacting motif peptide inhibitor significantly attenuates EndoMT and progression of atherosclerosis.

CONCLUSIONS

We conclude that epsins potentiate EndoMT during atherogenesis by increasing transforming growth factor-β signaling through fibroblast growth factor receptor-1 internalization and degradation. Inhibition of EndoMT by reducing epsin-fibroblast growth factor receptor-1 interaction with a therapeutic peptide may represent a novel treatment strategy for atherosclerosis.

Epsin Nanotherapy Regulates Cholesterol Transport to Fortify Atheroma Regression

BACKGROUND

Excess cholesterol accumulation in lesional macrophages elicits complex responses in atherosclerosis. Epsins, a family of endocytic adaptors, fuel the progression of atherosclerosis; however, the underlying mechanism and therapeutic potential of targeting Epsins remains unknown. In this study, we determined the role of Epsins in macrophage-mediated metabolic regulation. We then developed an innovative method to therapeutically target macrophage Epsins with specially designed S2P-conjugated lipid nanoparticles, which encapsulate small-interfering RNAs to suppress Epsins.

METHODS

We used single-cell RNA sequencing with our newly developed algorithm MEBOCOST (Metabolite-mediated Cell Communication Modeling by Single Cell Transcriptome) to study cell-cell communications mediated by metabolites from sender cells and sensor proteins on receiver cells. Biomedical, cellular, and molecular approaches were utilized to investigate the role of macrophage Epsins in regulating lipid metabolism and transport. We performed this study using myeloid-specific Epsin double knockout (LysM-DKO) mice and mice with a genetic reduction of ABCG1 (ATP-binding cassette subfamily G member 1; LysM-DKO-ABCG1fl/+). The nanoparticles targeting lesional macrophages were developed to encapsulate interfering RNAs to treat atherosclerosis.

RESULTS

We revealed that Epsins regulate lipid metabolism and transport in atherosclerotic macrophages. Inhibiting Epsins by nanotherapy halts inflammation and accelerates atheroma resolution. Harnessing lesional macrophage-specific nanoparticle delivery of Epsin small-interfering RNAs, we showed that silencing of macrophage Epsins diminished atherosclerotic plaque size and promoted plaque regression. Mechanistically, we demonstrated that Epsins bound to CD36 to facilitate lipid uptake by enhancing CD36 endocytosis and recycling. Conversely, Epsins promoted ABCG1 degradation via lysosomes and hampered ABCG1-mediated cholesterol efflux and reverse cholesterol transport. In a LysM-DKO-ABCG1fl/+ mouse model, enhanced cholesterol efflux and reverse transport due to Epsin deficiency was suppressed by the reduction of ABCG1.

CONCLUSIONS

Our findings suggest that targeting Epsins in lesional macrophages may offer therapeutic benefits for advanced atherosclerosis by reducing CD36-mediated lipid uptake and increasing ABCG1-mediated cholesterol efflux.

Genome-wide association study of the human brain functional connectome reveals strong vascular component underlying global network efficiency

Complex brain networks play a central role in integrating activity across the human brain, and such networks can be identified in the absence of any external stimulus. We performed 10 genome-wide association studies of resting state network measures of intrinsic brain activity in up to 36,150 participants of European ancestry in the UK Biobank. We found that the heritability of global network efficiency was largely explained by blood oxygen level-dependent (BOLD) resting state fluctuation amplitudes (RSFA), which are thought to reflect the vascular component of the BOLD signal. RSFA itself had a significant genetic component and we identified 24 genomic loci associated with RSFA, 157 genes whose predicted expression correlated with it, and 3 proteins in the dorsolateral prefrontal cortex and 4 in plasma. We observed correlations with cardiovascular traits, and single-cell RNA specificity analyses revealed enrichment of vascular related cells. Our analyses also revealed a potential role of lipid transport, store-operated calcium channel activity, and inositol 1,4,5-trisphosphate binding in resting-state BOLD fluctuations. We conclude that that the heritability of global network efficiency is largely explained by the vascular component of the BOLD response as ascertained by RSFA, which itself has a significant genetic component.

Individualized References of Carotid Stiffening Quantified With Ultrafast Ultrasound Imaging: Model Construction and Preliminary Validation

To establish and preliminarily validate an individualized reference of carotid stiffness quantified by ultrafast pulse wave velocity (ufPWV), our study included 225 healthy individuals in the modeling cohort and 628 individuals in the validation cohort. All participants underwent assessment of carotid intima-media thickness (cIMT), pulse wave velocity-beginning of systole and pulse wave velocity-end of systole (PWV-ES). A threshold equation of estimated PWV-ES was obtained by multiple linear regression analysis in the modeling cohort as follows: estimated PWV-ES (m/s) = 0.080 × age (y) + 0.767 × low-density lipoprotein (mmol/L) + 0.040 × systolic blood pressure (mm Hg) + 0.372 × sex (male = 1, female = 0) - 2.803. With this equation, the validation cohort was divided into the low PWV-ES (actual PWV-ES ≤ estimated PWV-ES) and high PWV-ES (actual PWV-ES > estimated PWV-ES) groups. A clear boundary was found to be present between the low PWV-ES and high PWV-ES groups in the validation cohort. Participants with increasing PWV-ES increased with age gradually. We further subdivided participants into cIMT subgroups using a cutoff thickness of 0.050 cm. Diagnostic performance analysis revealed that the sensitivity and specificity of the threshold equation were 78.9% and 73.9%, respectively. We established and validated a novel individualized reference equation for estimated PWV-ES, which can likely expand the application of prospective ufPWV assessment.

Effect of vinyl chloride exposure on cardiometabolic toxicity

Vinyl chloride (VC) is an organochlorine mainly used to manufacture its polymer polyvinyl chloride, which is extensively used in the manufacturing of consumer products. Recent studies suggest that chronic low dose VC exposure affects glucose homeostasis in high fat diet-fed mice. Our data suggest that even in the absence of high fat diet, exposure to VC (0.8 ppm, 6 h/day, 5 day/week, for 12 weeks) induces glucose intolerance (1.0 g/kg, i.p.) in male C57BL/6 mice. This was accompanied with the depletion of hepatic glutathione and a modest increase in lung interstitial macrophages. VC exposure did not affect the levels of circulating immune cells, endothelial progenitor cells, platelet-immune cell aggregates, and cytokines and chemokines. The acute challenge of VC-exposed mice with LPS did not affect lung immune cell composition or plasma IL-6. To examine the effect of VC exposure on vascular inflammation and atherosclerosis, LDL receptor-KO mice on C57BL/6 background maintained on western diet were exposed to VC for 12 weeks (0.8 ppm, 6 h/day, 5 day/week). Unlike the WT C57BL/6 mice, VC exposure did not affect glucose tolerance in the LDL receptor-KO mice. Plasma cytokines, lesion area in the aortic valve, and markers of lesional inflammation in VC-exposed LDL receptor-KO mice were comparable with the air-exposed controls. Collectively, despite impaired glucose tolerance and modest pulmonary inflammation, chronic low dose VC exposure does not affect surrogate markers of cardiovascular injury, LPS-induced acute inflammation in C57BL/6 mice, and chronic inflammation and atherosclerosis in the LDL receptor-KO mice.

Reactive Oxygen Species and Endothelial Ca2+ Signaling: Brothers in Arms or Partners in Crime?

An increase in intracellular Ca²⁺ concentration ([Ca²⁺]_i) controls virtually all endothelial cell functions and is, therefore, crucial to maintain cardiovascular homeostasis. An aberrant elevation in endothelial can indeed lead to severe cardiovascular disorders. Likewise, moderate amounts of reactive oxygen species (ROS) induce intracellular Ca²⁺ signals to regulate vascular functions, while excessive ROS production may exploit dysregulated Ca²⁺ dynamics to induce endothelial injury. Herein, we survey how ROS induce endothelial Ca²⁺ signals to regulate vascular functions and, vice versa, how aberrant ROS generation may exploit the Ca²⁺ handling machinery to promote endothelial dysfunction. ROS elicit endothelial Ca²⁺ signals by regulating inositol-1,4,5-trisphosphate receptors, sarco-endoplasmic reticulum Ca²⁺-ATPase 2B, two-pore channels, store-operated Ca²⁺ entry (SOCE), and multiple isoforms of transient receptor potential (TRP) channels. ROS-induced endothelial Ca²⁺ signals regulate endothelial permeability, angiogenesis, and generation of vasorelaxing mediators and can be exploited to induce therapeutic angiogenesis, rescue neurovascular coupling, and induce cancer regression. However, an increase in endothelial [Ca²⁺]_i induced by aberrant ROS formation may result in endothelial dysfunction, inflammatory diseases, metabolic disorders, and pulmonary artery hypertension. This information could pave the way to design alternative treatments to interfere with the life-threatening interconnection between endothelial ROS and Ca²⁺ signaling under multiple pathological conditions.

Epsins Negatively Regulate Aortic Endothelial Cell Function by Augmenting Inflammatory Signaling

Background: The endothelial epsin 1 and 2 endocytic adaptor proteins play an important role in atherosclerosis by regulating the degradation of the calcium release channel inositol 1,4,5-trisphosphate receptor type 1 (IP3R1). In this study, we sought to identify additional targets responsible for epsin-mediated atherosclerotic endothelial cell activation and inflammation in vitro and in vivo. Methods: Atherosclerotic ApoE^-/- mice and ApoE^-/- mice with an endothelial cell-specific deletion of epsin 1 on a global epsin 2 knock-out background (EC-iDKO/ApoE^-/-), and aortic endothelial cells isolated from these mice, were used to examine inflammatory signaling in the endothelium. Results: Inflammatory signaling was significantly abrogated by both acute (tumor necrosis factor-α (TNFα) or lipopolysaccharide (LPS)) and chronic (oxidized low-density lipoprotein (oxLDL)) stimuli in EC-iDKO/ApoE^-/- mice and murine aortic endothelial cells (MAECs) isolated from epsin-deficient animals when compared to ApoE^-/- controls. Mechanistically, the epsin ubiquitin interacting motif (UIM) bound to Toll-like receptors (TLR) 2 and 4 to potentiate inflammatory signaling and deletion of the epsin UIM mitigated this interaction. Conclusions: The epsin endocytic adaptor proteins potentiate endothelial cell activation in acute and chronic models of atherogenesis. These studies further implicate epsins as therapeutic targets for the treatment of inflammation of the endothelium associated with atherosclerosis.

EVA1A Plays an Important Role by Regulating Autophagy in Physiological and Pathological Processes

Eva-1 homolog A (EVA1A) is regarded as TMEM166 (transmembrane protein 166) or FAM176A (family with sequence similarity 176) and a lysosome and endoplasmic reticulum-associated protein involved in regulating autophagy and apoptosis. EVA1A regulates embryonic neurogenesis, cardiac remodeling, islet alpha-cell functions, acute liver failure, and hepatitis B virus replication. However, the related mechanisms are not fully clear. Autophagy is a process in which cells transfer pathogens, abnormal proteins and organelles to lysosomes for degradation. It plays an important role in various physiological and pathological processes, including cancer, aging, neurodegeneration, infection, heart disease, development, cell differentiation and nutritional starvation. Recently, there are many studies on the important role of EVA1A in many physiological and pathological processes by regulating autophagy. However, the related molecular mechanisms need further study. Therefore, we summarize the above-mentioned researches about the role of EVA1A in physiological and pathological processes through regulating autophagy in order to provide theoretical basis for future researches.

On-Chip Replication of Extremely Early-Stage Tumor Behavior

Cancer is a multistep progressive disease that generally involves tumor growth, invasion, and metastasis. It is crucial to understand tumor progression for tumor diagnosis and therapy. However, tumor progression at an extremely early stage (EES) is barely demonstrated because EES tumors are too small to be detected by imaging. Herein, we, for the first time, replicated tumor progression at the EES on a microfluidic chip and uncovered the tumor behaviors affected by the tumor microenvironment. To mimic the progression of a single solid tumor at the EES, a HeLa cell spheroid was seeded and cultured on the chip, and a microvascular network was developed to integrate the microphysiological contexts around the tumor. We revealed not only the growth patterns and cell behaviors of tumor spheroids of different sizes under angiogenesis and fibroblast conditions but also the effect of tumor progression on peritumoral angiogenesis. We found that smaller tumors were more aggressive and that endotheliocytes and fibroblasts significantly accelerated both the proliferation and migration of tumor cells. In addition, we also first present the dynamic epithelial-mesenchymal transition process of tumor cells and the formation of vasculogenic mimicry at the EES. This work can provide insights for understanding tumor progression at the EES and offer new ideas for tumor therapy.

Endocytic Adaptors in Cardiovascular Disease

Endocytosis is the process of actively transporting materials into a cell by membrane engulfment. Traditionally, endocytosis was divided into three forms: phagocytosis (cell eating), pinocytosis (cell drinking), and the more selective receptor-mediated endocytosis (clathrin-mediated endocytosis); however, other important endocytic pathways (e.g., caveolin-dependent endocytosis) contribute to the uptake of extracellular substances. In each, the plasma membrane changes shape to allow the ingestion and internalization of materials, resulting in the formation of an intracellular vesicle. While receptor-mediated endocytosis remains the best understood pathway, mammalian cells utilize each form of endocytosis to respond to their environment. Receptor-mediated endocytosis permits the internalization of cell surface receptors and their ligands through a complex membrane invagination process that is facilitated by clathrin and adaptor proteins. Internalized vesicles containing these receptor-ligand cargoes fuse with early endosomes, which can then be recycled back to the plasma membrane, delivered to other cellular compartments, or destined for degradation by fusing with lysosomes. These intracellular fates are largely determined by the interaction of specific cargoes with adaptor proteins, such as the epsins, disabled-homolog 2 (Dab2), the stonin proteins, epidermal growth factor receptor substrate 15, and adaptor protein 2 (AP-2). In this review, we focus on the role of epsins and Dab2 in controlling these sorting processes in the context of cardiovascular disease. In particular, we will focus on the function of epsins and Dab2 in inflammation, cholesterol metabolism, and their fundamental contribution to atherogenicity.

Epsins in vascular development, function and disease

Epsins are a family of adaptor proteins involved in clathrin-dependent endocytosis. In the vasculature, epsins 1 and 2 are functionally redundant members of this family that are expressed in the endothelial cells of blood vessels and the lymphatic system throughout development and adulthood. These proteins contain a number of peptide motifs that allow them to interact with lipid moieties and a variety of proteins. These interactions facilitate the regulation of a wide range of cell signaling pathways. In this review, we focus on the involvement of epsins 1 and 2 in controlling vascular endothelial growth factor receptor signaling in angiogenesis and lymphangiogenesis. We also discuss the therapeutic implications of understanding the molecular mechanisms of epsin-mediated regulation in diseases such as atherosclerosis and diabetes.