The extracellular matrix can regulate vascular cell migration, proliferation, and survival: relationships to vascular disease

Endovascular Drug Delivery

Drug-eluting stents (DES) and balloons revolutionize atherosclerosis treatment by targeting hyperplastic tissue responses through effective local drug delivery strategies. This review examines approved and emerging endovascular devices, discussing drug release mechanisms and their impacts on arterial drug distribution. It emphasizes the crucial role of drug delivery in modern cardiovascular care and highlights how device technologies influence vascular behavior based on lesion morphology. The future holds promise for lesion-specific treatments, particularly in the superficial femoral artery, with recent CE-marked devices showing encouraging results. Exciting strategies and new patents focus on local drug delivery to prevent restenosis, shaping the future of interventional outcomes. In summary, as we navigate the ever-evolving landscape of cardiovascular intervention, it becomes increasingly evident that the future lies in tailoring treatments to the specific characteristics of each lesion. By leveraging cutting-edge technologies and harnessing the potential of localized drug delivery, we stand poised to usher in a new era of precision medicine in vascular intervention.

Fibulin 1, targeted by microRNA-24-3p, promotes cell proliferation and migration in vascular smooth muscle cells, contributing to the development of atherosclerosis in APOE-/- mice

Extracellular matrix (ECM) and vascular smooth muscle cells (VSMCs) are the main components of atherosclerosis (AS) plaque. VSMCs participate in plaque formation through phenotypic transformation. The complex interplay between ECM and VSMCs plays vital roles in the progression of AS throughout the disease. An in-depth investigation into the functions of ECM-related molecules in VSMC development might contribute to deciphering the complexity of AS pathogenesis. In this study, the roles and molecular mechanisms of the ECM-related molecule Fibulin-1 (FBLN1) in the development of AS and VSMCs were explored using RNA sequencing, bioinformatics analysis, and cell experiments. Furthermore, the expression of FBLN1, as determined by western blot analysis, immunohistochemistry, and real-time quantitative PCR, was significantly increased in AS vascular samples compared to normal vascular samples. Silencing the FBLN1 through AAV viral injection in mice revealed an improvement in AS. Functional analyses revealed that FBLN1 promoted VSMC proliferation, migration, and wound healing. Combined with RNA sequencing and TargetScan7.2 prediction data, 22 microRNAs (miRNAs) were found to have the potential for direct interaction with the FBLN1 3'UTR in VSMCs. Among these 22 miRNAs, it was demonstrated that microRNA-24-3p (miR-24-3p) could negatively regulate FBLN1 expression by directly binding to the FBLN1 3'UTR. Moreover, miR-24-3p inhibited cell proliferation, migration, and wound healing, and suppressed the expression of Ki67, matrix metalloproteinase-2 and -9 (MMP2/9) by targeting FBLN1 in VSMCs. Meanwhile, inhibition of FBLN1 expression could restrain VSMC phenotypic transformation. In conclusion, miR-24-3p inhibited VSMC proliferation and migration by targeting FBLN1. Additionally, multiple miRNAs with the potential to interact with the FBLN1 3'UTR were identified. These findings might deepen our understanding of ECM gene regulatory networks and the complex etiology of AS.

Rutin promotes osteogenic differentiation of mesenchymal stem cells (MSCs) by increasing ECM deposition and inhibiting p53 expression

Mesenchymal stem cells (MSCs) are an important source of cells for bone regeneration. Although the utilization of MSCs along with growth factors and scaffolds is a beneficial clinical approach for bone tissue engineering, there is need for improvement on the effectiveness of MSC osteogenesis and differentiation. Rutin is a natural flavonoid and a major component for cell proliferation and bone development. However, studies on the mechanism through which rutin regulates osteogenesis and MSC differentiation are limited. Therefore, this study aimed to investigate the effect and mechanisms of rutin on osteogenic differentiation of MSCs. MSCs were extracted from umbilical cords and treated with rutin, followed by the examination of osteogenesis-related markers. Rutin treatment promoted the differentiation of MSCs towards the osteogenic lineage rather than the adipogenic lineage and increased the expression of osteogenic markers. RNA sequencing and bioinformatic analysis indicated that rutin regulated p53, a key gene in regulating the osteogenic differentiation of MSCs. Additionally, cellular experiments showed that rutin-induced decrease in p53 expression increased the formation of extracellular matrix (ECM) by promoting p65 phosphorylation and caspase-3 cleavage. Conclusively, this study demonstrates the importance of rutin in osteogenesis and indicates that rutin possesses potential pharmaceutical application for bone regeneration and bone tissue engineering.

Proteomics Studies Suggest That Nitric Oxide Donor Furoxans Inhibit In Vitro Vascular Smooth Muscle Cell Proliferation by Nitric Oxide-Independent Mechanisms

Physiologically, smooth muscle cells (SMC) and nitric oxide (NO) produced by endothelial cells strictly cooperate to maintain vasal homeostasis. In atherosclerosis, where this equilibrium is altered, molecules providing exogenous NO and able to inhibit SMC proliferation may represent valuable antiatherosclerotic agents. Searching for dual antiproliferative and NO-donor molecules, we found that furoxans significantly decreased SMC proliferation in vitro, albeit with different potencies. We therefore assessed whether this property is dependent on their thiol-induced ring opening. Indeed, while furazans (analogues unable to release NO) are not effective, furoxans' inhibitory potency parallels with the electron-attractor capacity of the group in 3 of the ring, making this effect tunable. To demonstrate whether their specific block on G1-S phase could be NO-dependent, we supplemented SMCs with furoxans and inhibitors of GMP- and/or of the polyamine pathway, which regulate NO-induced SMC proliferation, but they failed in preventing the antiproliferative effect. To find the real mechanism of this property, our proteomics studies revealed that eleven cellular proteins (with SUMO1 being central) and networks involved in cell homeostasis/proliferation are modulated by furoxans, probably by interaction with adducts generated after degradation. Altogether, thanks to their dual effect and pharmacological flexibility, furoxans may be evaluated in the future as antiatherosclerotic molecules.

A class of peptides designed to replicate and enhance the Receptor for Hyaluronic Acid Mediated Motility binding domain

The extra-cellular matrix (ECM) is a complex and rich microenvironment that is exposed and over-expressed across several injury or disease pathologies. Biomaterial therapeutics are often enriched with peptide binders to target the ECM with greater specificity. Hyaluronic acid (HA) is a major component of the ECM, yet to date, few HA adherent peptides have been discovered. A class of HA binding peptides was designed using B(X₇)B hyaluronic acid binding domains inspired from the helical face of the Receptor for Hyaluronic Acid Mediated Motility (RHAMM). These peptides were bioengineered using a custom alpha helical net method, allowing for the enrichment of multiple B(X₇)B domains and the optimisation of contiguous and non-contiguous domain orientations. Unexpectedly, the molecules also exhibited the behaviour of nanofiber forming self-assembling peptides and were investigated for this characteristic. Ten 23-27 amino acid residue peptides were assessed. Simple molecular modelling was used to depict helical secondary structures. Binding assays were performed with varying concentrations (1-10 mg/mL) and extra-cellular matrices (HA, collagens I-IV, elastin, and Geltrex). Concentration mediated secondary structures were assessed using circular dichroism (CD), and higher order nanostructures were visualized using transmission electron microscopy (TEM). All peptides formed the initial apparent 3₁₀/alpha-helices, yet peptides 17x-3, 4, BHP3 and BHP4 were HA specific and potent (i.e., a significant effect) binders at increasing concentrations. These peptides shifted from apparent 3₁₀/alpha-helical structures at low concentration to beta-sheets at increasing concentration and also formed nanofibers which are noted as self-assembling structures. Several of the HA binding peptides outperformed our positive control (mPEP35) at 3-4 times higher concentrations, and were enhanced by self-assembly as each of these groups had observable nanofibers. STATEMENT OF SIGNIFICANCE: Specific biomolecules or peptides have played a crucial role in developing materials or systems to deliver key drugs and therapeutics to a broad spectrum of diseases and disorders. In these diseased tissues, cells build protein/sugar networks, which are uniquely exposed and great targets to deliver drugs to. Hyaluronic acid (HA) is involved in every stage of injury and is abundant in cancer. To date, only two HA specific peptides have been discovered. In our work, we have designed a way to model and trace binding regions as they appear on the face of a helical peptide. Using this method we have created a family of peptides enriched with HA binding domains that stick with 3-4 higher affinity than those previously discovered.

Global trends and Frontier topics about vascular smooth muscle cells phenotype switch: A bibliometric analysis from 1999 to 2021

Objective: Vascular smooth muscle cell phenotype switch (VSMCPS) plays a significant role in vascular remodeling. This study aimed to conduct a bibliometric analysis and visualize the knowledge map of research on VSMCPS. Methods: We retrieved publications focusing on VSMCPS from the Web of Science Core Collection database (SCI-EXPANDED) from 1999 to 2021. Using bibliometric tools, VOSviewer and CiteSpace, we identified the most productive researchers, journals, institutions, and countries. At the same time, the trends, hot topics, and knowledge networks were analyzed and visualized. Results: A total of 2213 publications were included in this analysis. The number of annual publications in the VSMCPS field exhibited an upward trend and could be roughly divided into three phases. Until 2006, the most prolific authors were from the United States. As of 2008, the number of articles published in China increased dramatically to reach 126 papers in 2020. As of 2014, China was the most productive country in this field. The United States ranked first in the number of highly-influential authors, institutions, and literature from 1999 to 2022. Owens GK, Hata, Akiko, and Wen, jin-kun were the most prolific authors. Arteriosclerosis Thrombosis and Vascular Biology, Circulation Research, and Cardiovascular Research were the top-ranked journals in this field. "Vascular remodeling," "atherosclerosis," "neointima," "hypertension", and "inflammation" were the main researched topics. New diseases, new mechanisms, and new phenotype (e.g., micro RNA, macrophage-like-cell, hypoxia, autophagy, long noncoding RNA, oxidative stress, endoplasmic reticulum stress, senescence, aging, abdominal aortic aneurysm, and aortic dissection) represent the trending topics in recent years. Conclusion: This study systematically analyzed and visualized the knowledge map of VSMCPS over the past 2 decades. Our findings provide a comprehensive overview for scholars who want to understand current trends and new research frontiers in this area.

Exploring the difference in the mechanics of vascular smooth muscle cells from wild-type and apolipoprotein-E knockout mice

Atherosclerosis-related cardiovascular diseases are a leading cause of mortality worldwide. Vascular smooth muscle cells (VSMCs) comprise the medial layer of the arterial wall and undergo phenotypic switching during atherosclerosis to a synthetic phenotype capable of proliferation and migration. The surrounding environment undergoes alterations in extracellular matrix (ECM) stiffness and composition and an increase in cholesterol content. Using an atherosclerotic murine model, we analyzed how the mechanics of VSMCs isolated from Western diet-fed apolipoprotein-E knockout (ApoE-/-) and wild-type (WT) mice were altered during atherosclerosis. Increased stiffness of ApoE-/- VSMCs correlated with a greater degree of stress fiber alignment, as evidenced by atomic force microscopy (AFM)-generated force maps and stress fiber topography images. On type-1 collagen (COL1)-coated polyacrylamide (PA) gels (referred to as substrate) of varying stiffness, ApoE-/- VSMCs had lower adhesion forces to COL1 and N-cadherin (N-Cad) compared with WT cells. ApoE-/- VSMC stiffness was significantly greater than that of WT cells. Cell stiffness increased with increasing substrate stiffness for both ApoE-/- and WT VSMCs. In addition, ApoE-/- VSMCs showed an enhanced migration capability on COL1-coated substrates and a general decreasing trend in migration capacity with increasing substrate stiffness, correlating with lowered adhesion forces as compared with WT VSMCs. Altogether, these results demonstrate the potential contribution of the alteration in VSMC mechanics in the development of atherosclerosis.

Endothelial-Smooth Muscle Cell Interactions in a Shear-Exposed Intimal Hyperplasia on-a-Dish Model to Evaluate Therapeutic Strategies

Intimal hyperplasia (IH) represents a major challenge following cardiovascular interventions. While mechanisms are poorly understood, the inefficient preventive methods incentivize the search for novel therapies. A vessel-on-a-dish platform is presented, consisting of direct-contact cocultures with human primary endothelial cells (ECs) and smooth muscle cells (SMCs) exposed to both laminar pulsatile and disturbed flow on an orbital shaker. With contractile SMCs sitting below a confluent EC layer, a model that successfully replicates the architecture of a quiescent vessel wall is created. In the novel IH model, ECs are seeded on synthetic SMCs at low density, mimicking reendothelization after vascular injury. Over 3 days of coculture, ECs transition from a network conformation to confluent 2D islands, as promoted by pulsatile flow, resulting in a "defected" EC monolayer. In defected regions, SMCs incorporated plasma fibronectin into fibers, increased proliferation, and formed multilayers, similarly to IH in vivo. These phenomena are inhibited under confluent EC layers, supporting therapeutic approaches that focus on endothelial regeneration rather than inhibiting proliferation, as illustrated in a proof-of-concept experiment with Paclitaxel. Thus, this in vitro system offers a new tool to study EC-SMC communication in IH pathophysiology, while providing an easy-to-use translational disease model platform for low-cost and high-content therapeutic development.

Extracellular matrix regulates force transduction at VE-cadherin junctions

Increased tension on VE-cadherin (VE-cad) complexes activates adaptive cell stiffening and local cytoskeletal reinforcement--two key signatures of intercellular mechanotransduction. Here we demonstrate that tugging on VE-cad receptors initiates a cascade that results in downstream integrin activation. The formation of new integrin adhesions potentiates vinculin and actin recruitment to mechanically reinforce stressed cadherin adhesions. This cascade differs from documented antagonistic effects of integrins on intercellular junctions. We identify focal adhesion kinase, Abl kinase, and RhoA GTPase as key components of the positive feedback loop. Results further show that a consequence of integrin involvement is the sensitization of intercellular force transduction to the extracellular matrix (ECM) not by regulating junctional tension but by altering signal cascades that reinforce cell-cell adhesions. On type 1 collagen or fibronectin substrates, integrin subtypes α2β1 and α5β1, respectively, differentially control actin remodeling at VE-cad adhesions. Specifically, ECM-dependent differences in VE-cad force transduction mirror differences in the rigidity sensing mechanisms of α2β1 and α5β1 integrins. The findings verify the role of integrins in VE-cad force transduction and uncover a previously unappreciated mechanism by which the ECM impacts the mechanical reinforcement of interendothelial junctions.

Physico-mechanical and biological evaluation of heparin/VEGF-loaded electrospun polycaprolactone/decellularized rat aorta extracellular matrix for small-diameter vascular grafts

Although the continuous development of small-diameter vascular grafts (SDVGs) (D < 5 mm) continues, most vascular grafts are made from synthetic polymers, which lead to serious complications from arteriosclerosis, thrombosis, and vascular ischemia. Here, to address these shortcomings, we combine synthetic polymers with natural decellularized small-diameter vessels and loaded with growth factor. We fabricated vascular grafts by electrospinning polycaprolactone (PCL) to decellularized rat aorta matrix (ECM) followed by heparin and vascular endothelial growth factor (VEGF) loading. In- vitro studies showed that PCL/ECM/VEGF vascular grafts, showed excellent hemocompatibility and biocompatibility properties. The vascular grafts implanted into the rat aorta revealed that the PCL/ECM/VEGF grafts promotes endothelial cells and smooth-muscle cells infiltration with a rate of FLK-1, ICAM1, and a-SMA distribution higher than that of the PCL and PCL/ECM vascular grafts at 2 weeks and 4 weeks after implantation. The PCL/ECM/VEGF vascular graft should be considered for potential small-diameter vascular grafts in clinical fields.

A Model for Cell Proliferation in a Developing Organism

In mathematical biology, there is a great deal of interest in producing continuum models by scaling discrete agent-based models governed by local stochastic rules. We discuss a particular example of this approach: a model for the proliferation of neural crest cells that can help us understand the development of Hirschprung's disease, a potentially-fatal condition in which the enteric nervous system of a new-born child does not extend all the way through the intestine and colon. Our starting point is a discrete-state, continuous-time Markov chain model proposed by Hywood et al. (2013a) for the location of the neural crest cells that make up the enteric nervous system. Hywood et al. (2013a) scaled their model to derive an approximate second order partial differential equation describing how the limiting expected number of neural crest cells evolve in space and time. In contrast, we exploit the relationship between the above-mentioned Markov chain model and the well-known Yule-Furry process to derive the exact form of the scaled version of the process. Furthermore, we provide expressions for other features of the domain agent occupancy process, such as the variance of the marginal occupancy at a particular site, the distribution of the number of agents that are yet to reach a given site and a stochastic description of the process itself.

Peroxynitrous acid-modified extracellular matrix alters gene and protein expression in human coronary artery smooth muscle cells and induces a pro-inflammatory phenotype

Leukocytes produce oxidants at inflammatory sites, including within the artery wall during the development of atherosclerosis. Developing lesions contain high numbers of activated leukocytes that generate reactive nitrogen species, including peroxynitrite/peroxynitrous acid (ONOO^-/ONOOH), as evidenced by the presence of oxidized/nitrated molecules including extracellular matrix (ECM) proteins. ECM materials are critical for arterial wall integrity, function, and determine cell phenotype, with smooth muscle cells undergoing a phenotypic switch from quiescent/contractile to proliferative/synthetic during disease development. We hypothesized that ECM modification by ONOO^-/ONOOH might drive this switch, and thereby potentially contribute to atherogenesis. ECM generated by primary human coronary artery smooth muscle cells (HCASMCs) was treated with increasing ONOO^-/ONOOH concentrations (1-1000 μM). This generated significant damage on laminin, fibronectin and versican, and lower levels on collagens and glycosaminoglycans, together with the increasing concentrations of the damage biomarker 3-nitrotyrosine. Adhesion of naïve HCASMC to ECM modified by 1 μM ONOO^-/ONOOH was enhanced, but significantly diminished by higher ONOO^-/ONOOH treatment. Cell proliferation and metabolic activity were significantly enhanced by 100 μM ONOO^-/ONOOH pre-treatment. These changes were accompanied by increased expression of genes involved in mitosis (PCNA, CCNA1, CCNB1), ECM (LAMA4, LAMB1, VCAN, FN1) and inflammation (IL-1B, IL-6, VCAM-1), and corresponding protein secretion (except VCAM-1) into the medium. These changes induced by modified ECM are consistent with HCASMC switching to a synthetic/proliferative/pro-inflammatory phenotype, together with ECM remodelling. These changes model those in atherosclerosis, suggesting a link between oxidant-modified ECM and disease progression, and highlight the potential of targeting oxidant generation as a therapeutic strategy.

Syndecan-1 Is Overexpressed in Human Thoracic Aneurysm but Is Dispensable for the Disease Progression in a Mouse Model

Glycosaminoglycans (GAGs) pooling has long been considered as one of the histopathological characteristics defining thoracic aortic aneurysm (TAA) together with smooth muscle cells (SMCs) apoptosis and elastin fibers degradation. However, little information is known about GAGs composition or their potential implication in TAA pathology. Syndecan-1 (SDC-1) is a heparan sulfate proteoglycan that is implicated in extracellular matrix (ECM) interaction and assembly, regulation of SMCs phenotype, and various aspects of inflammation in the vascular wall. Therefore, the aim of this study was to determine whether SDC-1 expression was regulated in human TAA and to analyze its role in a mouse model of this disease. In the current work, the regulation of SDC-1 was examined in human biopsies by RT-qPCR, ELISA, and immunohistochemistry. In addition, the role of SDC-1 was evaluated in descending TAA in vivo using a mouse model combining both aortic wall weakening and hypertension. Our results showed that both SDC-1 mRNA and protein are overexpressed in the media layer of human TAA specimens. RT-qPCR experiments revealed a 3.6-fold overexpression of SDC-1 mRNA (p = 0.0024) and ELISA assays showed that SDC-1 protein was increased 2.3 times in TAA samples compared with healthy counterparts (221 ± 24 vs. 96 ± 33 pg/mg of tissue, respectively, p = 0.0012). Immunofluorescence imaging provided evidence that SMCs are the major cell type expressing SDC-1 in TAA media. Similarly, in the mouse model used, SDC-1 expression was increased in TAA specimens compared to healthy samples. Although its protective role against abdominal aneurysm has been reported, we observed that SDC-1 was dispensable for TAA prevalence or rupture. In addition, SDC-1 deficiency did not alter the extent of aortic wall dilatation, elastin degradation, collagen deposition, or leukocyte recruitment in our TAA model. These findings suggest that SDC-1 could be a biomarker revealing TAA pathology. Future investigations could uncover the underlying mechanisms leading to regulation of SDC-1 expression in TAA.

3D Tissue-Engineered Vascular Drug Screening Platforms: Promise and Considerations

Despite the efforts devoted to drug discovery and development, the number of new drug approvals have been decreasing. Specifically, cardiovascular developments have been showing amongst the lowest levels of approvals. In addition, concerns over the adverse effects of drugs to the cardiovascular system have been increasing and resulting in failure at the preclinical level as well as withdrawal of drugs post-marketing. Besides factors such as the increased cost of clinical trials and increases in the requirements and the complexity of the regulatory processes, there is also a gap between the currently existing pre-clinical screening methods and the clinical studies in humans. This gap is mainly caused by the lack of complexity in the currently used 2D cell culture-based screening systems, which do not accurately reflect human physiological conditions. Cell-based drug screening is widely accepted and extensively used and can provide an initial indication of the drugs' therapeutic efficacy and potential cytotoxicity. However, in vitro cell-based evaluation could in many instances provide contradictory findings to the in vivo testing in animal models and clinical trials. This drawback is related to the failure of these 2D cell culture systems to recapitulate the human physiological microenvironment in which the cells reside. In the body, cells reside within a complex physiological setting, where they interact with and respond to neighboring cells, extracellular matrix, mechanical stress, blood shear stress, and many other factors. These factors in sum affect the cellular response and the specific pathways that regulate variable vital functions such as proliferation, apoptosis, and differentiation. Although pre-clinical in vivo animal models provide this level of complexity, cross species differences can also cause contradictory results from that seen when the drug enters clinical trials. Thus, there is a need to better mimic human physiological conditions in pre-clinical studies to improve the efficiency of drug screening. A novel approach is to develop 3D tissue engineered miniaturized constructs in vitro that are based on human cells. In this review, we discuss the factors that should be considered to produce a successful vascular construct that is derived from human cells and is both reliable and reproducible.

An update on the phenotypic switching of vascular smooth muscle cells in the pathogenesis of atherosclerosis

Vascular smooth muscle cells (VSMCs) are involved in phenotypic switching in atherosclerosis. This switching is characterized by VSMC dedifferentiation, migration, and transdifferentiation into other cell types. VSMC phenotypic transitions have historically been considered bidirectional processes. Cells can adopt a physiological contraction phenotype or an alternative "synthetic" phenotype in response to injury. However, recent studies, including lineage tracing and single-cell sequencing studies, have shown that VSMCs downregulate contraction markers during atherosclerosis while adopting other phenotypes, including macrophage-like, foam cell, mesenchymal stem-like, myofibroblast-like, and osteochondral-like phenotypes. However, the molecular mechanism and processes regulating the switching of VSMCs at the onset of atherosclerosis are still unclear. This systematic review aims to review the critical outstanding challenges and issues that need further investigation and summarize the current knowledge in this field.

A collagen I derived matricryptin increases aorta vascular wall remodeling after induced thrombosis in mouse

Matricryptins are collagen fragments proteolytically released from the extracellular matrix (ECM) with biological activity that can regulate several processes involved in ECM remodeling. Vessel wall matrix reorganization after lesion is important to the recovery of vascular function. This study aimed to analyze the effect of the peptide p1158/59 (Lindsey, 2015) on thrombosis, neointimal formation, and vascular remodeling of C57BL6 mice abdominal aorta. We used a FeCl₃ induced vascular injury mice model and analyzed thrombus size, neointima formation, gelatinase activities in situ, re-endothelization, and collagen fibers organization on the arterial wall using polarization microscopy. As result, we observed that 2 days after injury the treatment with p1158/59 increased thrombus size and gelatinase activity, vascular lesion and it did not recover the endothelium loss induced by the chemical injury. We also observed that the peptide increased neointima growth and collagen birefringence, indicating collagen fibers reorganization. It also promoted increased re-endothelization and decreased activity of gelatinases 14 days after injury. Thus, we conclude that the peptide p1158/59 impaired the initial thrombosis recovery 2 days after injury but was able to induce vascular ECM remodeling after 14 days, improving vessel re-endothelization, collagen fibers deposition, and organization.

Twenty-Five Novel Loci for Carotid Intima-Media Thickness: A Genome-Wide Association Study in >45 000 Individuals and Meta-Analysis of >100 000 Individuals

OBJECTIVE

Carotid artery intima-media thickness (cIMT) is a widely accepted marker of subclinical atherosclerosis. Twenty susceptibility loci for cIMT were previously identified and the identification of additional susceptibility loci furthers our knowledge on the genetic architecture underlying atherosclerosis. Approach and Results: We performed 3 genome-wide association studies in 45 185 participants from the UK Biobank study who underwent cIMT measurements and had data on minimum, mean, and maximum thickness. We replicated 15 known loci and identified 20 novel loci associated with cIMT at P<5×10^-8. Seven novel loci (ZNF385D, ADAMTS9, EDNRA, HAND2, MYOCD, ITCH/EDEM2/matrix metalloproteinase [MMP]24, and MRTFA) were identified in all 3 phenotypes. An additional new locus (LOXL1) was identified in the meta-analysis of the 3 phenotypes. Sex interaction analysis revealed sex differences in 7 loci including a novel locus (SYNE3) in males. Meta-analysis of UK Biobank data with a previous meta-analysis led to identification of three novel loci (APOB, FIP1L1, and LOXL4). Transcriptome-wide association analyses implicated additional genes ARHGAP42, NDRG4, and KANK2. Gene set analysis showed an enrichment in extracellular organization and the PDGF (platelet-derived growth factor) signaling pathway. We found positive genetic correlations of cIMT with coronary artery disease r_g=0.21 (P=1.4×10^-7), peripheral artery disease r_g=0.45 (P=5.3×10^-5), and systolic blood pressure r_g=0.30 (P=4.0×10^-18). A negative genetic correlation between average of maximum cIMT and high-density lipoprotein was found r_g=-0.12 (P=7.0×10^-4).

CONCLUSIONS

Genome-wide association meta-analyses in >100 000 individuals identified 25 novel loci associated with cIMT providing insights into genes and tissue-specific regulatory mechanisms of proatherosclerotic processes. We found evidence for shared biological mechanisms with cardiovascular diseases.

The Role of Decorin and Biglycan Signaling in Tumorigenesis

The complex and adaptive nature of malignant neoplasm constitute a major challenge for the development of effective anti-oncogenic therapies. Emerging evidence has uncovered the pivotal functions exerted by the small leucine-rich proteoglycans, decorin and biglycan, in affecting tumor growth and progression. In their soluble forms, decorin and biglycan act as powerful signaling molecules. By receptor-mediated signal transduction, both proteoglycans modulate key processes vital for tumor initiation and progression, such as autophagy, inflammation, cell-cycle, apoptosis, and angiogenesis. Despite of their structural homology, these two proteoglycans interact with distinct cell surface receptors and thus modulate distinct signaling pathways that ultimately affect cancer development. In this review, we summarize growing evidence for the complex roles of decorin and biglycan signaling in tumor biology and address potential novel therapeutic implications.

Exosome-eluting stents for vascular healing after ischaemic injury

Drug-eluting stents implanted after ischaemic injury reduce the proliferation of endothelial cells and vascular smooth muscle cells and thus neointimal hyperplasia. However, the eluted drug also slows down the re-endothelialization process, delays arterial healing and can increase the risk of late restenosis. Here we show that stents releasing exosomes derived from mesenchymal stem cells in the presence of reactive oxygen species enhance vascular healing in rats with renal ischaemia-reperfusion injury, promoting endothelial cell tube formation and proliferation, and impairing the migration of smooth muscle cells. Compared with drug-eluting stents and bare-metal stents, the exosome-coated stents accelerated re-endothelialization and decreased in-stent restenosis 28 days after implantation. We also show that exosome-eluting stents implanted in the abdominal aorta of rats with unilateral hindlimb ischaemia regulated macrophage polarization, reduced local vascular and systemic inflammation, and promoted muscle tissue repair.

Intimal Hyperplasia and Arteriovenous Fistula Failure: Looking Beyond Size Differences

The development of venous intimal hyperplasia (IH) has been historically associated with failure of arteriovenous fistulas (AVF) used for hemodialysis. This long-standing assumption, based on histological observations, has been recently challenged by clinical studies indicating that the size of the intima by itself is not enough to explain stenosis or AVF maturation failure. Irrespective of this lack of association, IH is present in most native veins and fistulas, is prominent in many cases, and suggests a role in the vein that may not be reflected by its dimensions. Therefore, the contribution of IH to AVF dysfunction remains controversial. Using only clinical data and avoiding extrapolations from animal models, we critically discuss the biological significance of IH in vein remodeling, vascular access function, and the response of the venous wall to repeated trauma in hemodialysis patients. We address questions and pose new ones such as: What are the factors that contribute to IH in pre-access veins and AVFs? Do cellular phenotypes and composition of the intima influence AVF function? Are there protective roles of the venous intima? This review explores these possibilities, with hopes of rekindling a critical discussion about venous IH that goes beyond thickness and AVF outcomes.

The dynamic change of phenotypic markers of smooth muscle cells in an animal model of cerebral small vessel disease

BACKGROUND

The pathological character of cerebral small vessel disease (CSVD) is the dysfunction of cerebral small arteries caused by risk factors. A switch from the contractile phenotype to the synthetic phenotype of vascular smooth muscle cells (SMCs) can decrease the contractility of arteries. The alteration of the vascular wall extracellular matrix (ECM) is found to regulate the process. We speculated that SMCs phenotype changes may also occur in CSVD induced by hypertension and the alteration of ECM especially fibronectin and laminin may regulate the process.

METHOD

Male spontaneously hypertensive rats (SHR) were used as a CSVD animal model. SMCs phenotypic markers and the ECM expression of the cerebral small arteries of SHR at different ages were evaluated by immunofluorescence. The phenotype changes of primary brain microvascular SMCs cultured on laminin-coating dish or fibronectin-coating dish were evaluated by western blot.

RESULT

A switch from the contractile phenotype to synthetic phenotype in SHR at 10 and 22 weeks of age was observed. Meanwhile, increased expression of fibronectin and a temporary decline of laminin was found in small arteries of SHR at 22 weeks. In vitro experiments also convinced that SMCs cultured on a fibronectin-coating dish failed to maintain contractile phenotype. While at 50 weeks, significant drops of both synthetic and contractile phenotypic markers were witnessed in SHR, with high expressions of four kinds of ECM.

CONCLUSION

SMCs in cerebral small arteries exhibited a switch from the contractile phenotype to synthetic phenotype during the chronic process of hypertension and aging. Moreover, the change of fibronectin and laminin may regulate the process.

Primary Ciliary Signaling in the Skin-Contribution to Wound Healing and Scarring

Primary cilia (PC) are solitary, post-mitotic, microtubule-based, and membrane-covered protrusions that are found on almost every mammalian cell. PC are specialized cellular sensory organelles that transmit environmental information to the cell. Signaling through PC is involved in the regulation of a variety of cellular processes, including proliferation, differentiation, and migration. Conversely, defective, or abnormal PC signaling can contribute to the development of various pathological conditions. Our knowledge of the role of PC in organ development and function is largely based on ciliopathies, a family of genetic disorders with mutations affecting the structure and function of PC. In this review, we focus on the role of PC in their major signaling pathways active in skin cells, and their contribution to wound healing and scarring. To provide comprehensive insights into the current understanding of PC functions, we have collected data available in the literature, including evidence across cell types, tissues, and animal species. We conclude that PC are underappreciated subcellular organelles that significantly contribute to both physiological and pathological processes of the skin development and wound healing. Thus, PC assembly and disassembly and PC signaling may serve as attractive targets for antifibrotic and antiscarring therapies.

Endothelial TGF-β signaling instructs smooth muscle cell development in the cardiac outflow tract

The development of the cardiac outflow tract (OFT), which connects the heart to the great arteries, relies on a complex crosstalk between endothelial (ECs) and smooth muscle (SMCs) cells. Defects in OFT development can lead to severe malformations, including aortic aneurysms, which are frequently associated with impaired TGF-β signaling. To better understand the role of TGF-β signaling in OFT formation, we generated zebrafish lacking the TGF-β receptor Alk5 and found a strikingly specific dilation of the OFT: alk5-/- OFTs exhibit increased EC numbers as well as extracellular matrix (ECM) and SMC disorganization. Surprisingly, endothelial-specific alk5 overexpression in alk5-/- rescues the EC, ECM, and SMC defects. Transcriptomic analyses reveal downregulation of the ECM gene fibulin-5, which when overexpressed in ECs ameliorates OFT morphology and function. These findings reveal a new requirement for endothelial TGF-β signaling in OFT morphogenesis and suggest an important role for the endothelium in the etiology of aortic malformations.

The basement membrane as a structured surface - role in vascular health and disease

The basement membrane (BM) is a thin specialized extracellular matrix that functions as a cellular anchorage site, a physical barrier and a signaling hub. While the literature on the biochemical composition and biological activity of the BM is extensive, the central importance of the physical properties of the BM, most notably its mechanical stiffness and topographical features, in regulating cellular function has only recently been recognized. In this Review, we focus on the biophysical attributes of the BM and their influence on cellular behavior. After a brief overview of the biochemical composition, assembly and function of the BM, we describe the mechanical properties and topographical structure of various BMs. We then focus specifically on the vascular BM as a nano- and micro-scale structured surface and review how its architecture can modulate endothelial cell structure and function. Finally, we discuss the pathological ramifications of the biophysical properties of the vascular BM and highlight the potential of mimicking BM topography to improve the design of implantable endovascular devices and advance the burgeoning field of vascular tissue engineering.

Tuning the selective permeability of polydisperse polymer networks

We study the permeability and selectivity ('permselectivity') of model membranes made of polydisperse polymer networks for molecular penetrant transport, using coarse-grained, implicit-solvent computer simulations. In our work, permeability P is determined on the linear-response level using the solution-diffusion model, P = KDin, i.e., by calculating the equilibrium penetrant partition ratio K and penetrant diffusivity Din inside the membrane. We vary two key parameters, namely the network-network interaction, which controls the degree of swelling and collapse of the network, and the network-penetrant interaction, which tunes the selective penetrant uptake and microscopic energy landscape for diffusive transport. We find that the partitioning K covers four orders of magnitude and is a non-monotonic function of the parameters, well interpreted by a second-order virial expansion of the free energy of transferring one penetrant from a reservoir into the membrane. Moreover, we find that the penetrant diffusivity Din in the polydisperse networks, in contrast to highly ordered membrane structures, exhibits relatively simple exponential decays. We propose a semi-empirical scaling law for the penetrant diffusion that describes the simulation data for a wide range of densities and interaction parameters. The resulting permeability P turns out to follow the qualitative behavior (including maximization and minimization) of partitioning. However, partitioning and diffusion are typically anti-correlated, yielding large quantitative cancellations, controlled and fine-tuned by the network density and interactions, as rationalized by our scaling laws. We finally demonstrate that even small changes of network-penetrant interactions, e.g., by half a kBT, modify the permselectivity by almost one order of magnitude.

Extracellular matrix compression temporally regulates microvascular angiogenesis

Mechanical cues influence tissue regeneration, and although vasculature is known to be mechanically sensitive, little is known about the effects of bulk extracellular matrix deformation on the nascent vessel networks found in healing tissues. Previously, we found that dynamic matrix compression in vivo potently regulated revascularization during bone tissue regeneration; however, whether matrix deformations directly regulate angiogenesis remained unknown. Here, we demonstrated that load initiation time, magnitude, and mode all regulate microvascular growth, as well as upstream angiogenic and mechanotransduction signaling pathways. Immediate load initiation inhibited angiogenesis and expression of early sprout tip cell selection genes, while delayed loading enhanced microvascular network formation and upstream signaling pathways. This research provides foundational understanding of how extracellular matrix mechanics regulate angiogenesis and has critical implications for clinical translation of new regenerative medicine therapies and physical rehabilitation strategies designed to enhance revascularization during tissue regeneration.

Smooth muscle cell-specific fibronectin-EDA mediates phenotypic switching and neointimal hyperplasia

Fibronectin-splice variant containing extra domain A (Fn-EDA) is associated with smooth muscle cells (SMCs) following vascular injury. The role of SMC-derived Fn-EDA in SMC phenotypic switching or its implication in neointimal hyperplasia remains unclear. Herein, using human coronary artery sections with a bare metal stent, we demonstrate the expression of Fn-EDA in the vicinity of SMC-rich neointima and peri-strut areas. In mice, Fn-EDA colocalizes with SMCs in the neointima of injured carotid arteries and promotes neointima formation in the comorbid condition of hyperlipidemia by potentiating SMC proliferation and migration. No sex-based differences were observed. Mechanistic studies suggested that Fn-EDA mediates integrin- and TLR4-dependent proliferation and migration through activation of FAK/Src and Akt1/mTOR signaling, respectively. Specific deletion of Fn-EDA in SMCs, but not in endothelial cells, reduced intimal hyperplasia and suppressed the SMC synthetic phenotype concomitant with decreased Akt1/mTOR signaling. Targeting Fn-EDA in human aortic SMCs suppressed the synthetic phenotype and downregulated Akt1/mTOR signaling. These results reveal that SMC-derived Fn-EDA potentiates phenotypic switching in human and mouse aortic SMCs and neointimal hyperplasia in the mouse. We suggest that targeting Fn-EDA could be explored as a potential therapeutic strategy to reduce neointimal hyperplasia.

Differential Roles of Endothelial Cell-Derived and Smooth Muscle Cell-Derived Fibronectin Containing Extra Domain A in Early and Late Atherosclerosis

OBJECTIVE

The extracellular matrix of atherosclerotic arteries contains abundant deposits of cellular Fn-EDA (fibronectin containing extra domain A), suggesting a functional role in the pathophysiology of atherosclerosis. Fn-EDA is synthesized by several cell types, including endothelial cells (ECs) and smooth muscle cells (SMCs), which are known to contribute to different stages of atherosclerosis. Although previous studies using global Fn-EDA-deficient mice have demonstrated that Fn-EDA is proatherogenic, the cell-specific role of EC versus SMC-derived-Fn-EDA in atherosclerosis has not been investigated yet. Approach and Results: To determine the relative contribution of different pools of Fn-EDA in atherosclerosis, we generated mutant strains lacking Fn-EDA in the ECs (Fn-EDAEC-KO) or smooth muscle cells (Fn-EDASMC-KO) on apolipoprotein E-deficient (Apoe-/-) background. The extent of atherosclerotic lesion progression was evaluated in whole aortae, and cross-sections of the aortic sinus in male and female mice fed a high-fat Western diet for either 4 weeks (early atherosclerosis) or 14 weeks (late atherosclerosis). Irrespective of sex, Fn-EDAEC-KO, but not Fn-EDASMC-KO mice, exhibited significantly reduced early atherogenesis concomitant with decrease in inflammatory cells (neutrophil and macrophage) and VCAM-1 (vascular cell adhesion molecule-1) expression levels within the plaques. In late atherosclerosis model, irrespective of sex, Fn-EDASMC-KO mice exhibited significantly reduced atherogenesis, but not Fn-EDAEC-KO mice, that was concomitant with decreased macrophage content within plaques. Lesional SMCs, collagen content, and plasma inflammatory cytokines (TNF-α [tumor necrosis factor-α] and IL-1β [interleukin-1β]), total cholesterol, and triglyceride levels were comparable among groups.

CONCLUSIONS

EC-derived Fn-EDA contributes to early atherosclerosis, whereas SMC-derived Fn-EDA contributes to late atherosclerosis.

Melatonin enhances atherosclerotic plaque stability by inducing prolyl-4-hydroxylase α1 expression

OBJECTIVE

Melatonin, an endogenous neurohormone secreted predominately by the pineal gland, has a variety of physiological functions. However, its protective role in atherosclerosis is not clear. In this study, we sought to investigate the potential effects of melatonin in modulating atherosclerotic plaque stability in apolipoprotein E knockout (ApoE) mice.

METHOD AND RESULTS

Smooth muscle cells were treated with melatonin, which significantly increased mRNA and protein levels of a key intracellular enzyme essential for collagen maturation and secretion, prolyl-4-hydroxylase α1 (P4Hα1). Mechanistically, melatonin increased Akt phosphorylation and transcriptional activation of specificity protein 1 (Sp1), which bound with the P4Hα1 promoter and then induced P4Hα1 expression. Pretreatment with either Akt inhibitor LY294002 or Sp1 inhibitor mithramycin A (MTM) could inhibit melatonin-induced P4Hα1 expression. Finally, atherosclerotic lesions were induced by placing a perivascular collar on the right common carotid artery of ApoE mice, which were received with or without different doses of melatonin or MTM. High-dose melatonin enhanced atherosclerotic plaque stability in ApoE mice in vivo by inducing the expression of P4Hα1, which was reversed by MTM.

CONCLUSION

We propose that melatonin supplementation may provide a novel and promising approach to atherosclerosis treatment.

Extracellular Matrix Proteins and Substrate Stiffness Synergistically Regulate Vascular Smooth Muscle Cell Migration and Cortical Cytoskeleton Organization

Vascular smooth muscle cell (VSMC) migration is a critical step in the progression of cardiovascular disease and aging. Migrating VSMCs encounter a highly heterogeneous environment with the varying extracellular matrix (ECM) composition due to the differential synthesis of collagen and fibronectin (FN) in different regions and greatly changing stiffness, ranging from the soft necrotic core of plaques to hard calcifications within blood vessel walls. In this study, we demonstrate an application of a two-dimensional (2D) model consisting of an elastically tunable polyacrylamide gel of varying stiffness and ECM protein coating to study VSMC migration. This model mimics the in vivo microenvironment that VSMCs experience within a blood vessel wall, which may help identify potential therapeutic targets for the treatment of atherosclerosis. We found that substrate stiffness had differential effects on VSMC migration on type 1 collagen (COL1) and FN-coated substrates. VSMCs on COL1-coated substrates showed significantly diminished migration distance on stiffer substrates, while on FN-coated substrates VSMCs had significantly increased migration distance. In addition, cortical stress fiber orientation increased in VSMCs cultured on more rigid COL1-coated substrates, while decreasing on stiffer FN-coated substrates. On both proteins, a more disorganized cytoskeletal architecture was associated with faster migration. Overall, these results demonstrate that different ECM proteins can cause substrate stiffness to have differential effects on VSMC migration in the progression of cardiovascular diseases and aging.

Effects of a Matrix Metalloproteinase Inhibitor-Eluting Stent on In-Stent Restenosis

Background

The aim of this study was to compare changes in the extracellular matrix after implantation of a stent that elutes a matrix metalloproteinase (MMP) inhibitor (GM6001); and to determine the effects of the GM6001-eluting stent upon prevention of in-stent restenosis (ISR).

Material/Methods

We included 48 Guangxi Bama mini-pigs in this study. A GM6001-eluting stent was placed in one iliac artery and a stent that did not elute GM6001 was placed in the contralateral iliac artery. The iliac arteries were removed at 6 hours as well as 1, 7, 14, 56, 84, and 336 days after stent placement. Arteries were analyzed for morphometry, gelatinase content, different phenotypes of vascular smooth muscle cells (VSMCs), collagen content, apoptotic rate, and cell density.

Results

The vascular lumen areas of the GM6001 group were significantly increased and the neointimal areas were significantly reduced compared with the control group from the 7 days to the 336 days. In the 2 groups, expression of MMP-2 and MMP-9 peaked simultaneously, but GM6001-eluting stents inhibited expression of MMP-2 and MMP-9 in the vascular media and neointima (especially around the struts) significantly. In the GM6001 group, expression of tissue inhibitor of matrix metalloproteinase (TIMP)-1, TIMP-2, myosin heavy chain 10 (MYH-10, marker of the proliferative phenotype of VSMCs), collagen content, percentage of apoptotic cells, and cell density were also decreased significantly compared with those in the control group.

Conclusion

Use of GM6001-eluting stents resulted in persistent and potent inhibition of intimal hyperplasia, an increase in luminal area, and no obvious thrombosis in the arteries of the mini-pigs.

Biglycan and atherosclerosis: Lessons from high cardiovascular risk conditions

Atherosclerosis (ATH) is a chronic, dynamic, evolutive process involving morphological and structural subversion of artery walls, leading to the formation of atherosclerotic plaques. ATH generally initiates during the childhood, occurring as a result of a number of changes in the intima tunica and in the media of arteries. A key event occurring during the pathobiology of ATH is the accumulation of lipoproteins in the sub-intimal spaces mediated by extracellular matrix (ECM) molecules, especially by the chondroitin sulfate/dermatan sulfate (CS/DS) -containing proteoglycans (CS/DSPGs). Among them, the proteoglycan biglycan (BGN) is critically involved in the onset and progression of ATH and evidences show that BGN represents the missing link between the pro-atherogenic status induced by both traditional and non-traditional cardiovascular risk factors and the development and progression of vascular damage. In the light of these findings, the role of BGN in dyslipidemia, hypertension, cigarette smoking, diabetes, chronic kidney disease and inflammatory status is briefly analyzed and discussed in order to shed new light on the underlying mechanisms governing the association between BGN and ATH.

Multiphoton microscopy of the dermoepidermal junction and automated identification of dysplastic tissues with deep learning

Histopathological image analysis performed by a trained expert is currently regarded as the gold-standard for the diagnostics of many pathologies, including cancers. However, such approaches are laborious, time consuming and contain a risk for bias or human error. There is thus a clear need for faster, less intrusive and more accurate diagnostic solutions, requiring also minimal human intervention. Multiphoton microscopy (MPM) can alleviate some of the drawbacks specific to traditional histopathology by exploiting various endogenous optical signals to provide virtual biopsies that reflect the architecture and composition of tissues, both in-vivo or ex-vivo. Here we show that MPM imaging of the dermoepidermal junction (DEJ) in unstained fixed tissues provides useful cues for a histopathologist to identify the onset of non-melanoma skin cancers. Furthermore, we show that MPM images collected on the DEJ, besides being easy to interpret by a trained specialist, can be automatically classified into healthy and dysplastic classes with high precision using a Deep Learning method and existing pre-trained convolutional neural networks. Our results suggest that deep learning enhanced MPM for in-vivo skin cancer screening could facilitate timely diagnosis and intervention, enabling thus more optimal therapeutic approaches.

Fiber Scaffold Patterning for Mending Hearts: 3D Organization Bringing the Next Step

Heart failure (HF) is a leading cause of death worldwide. The most common conditions that lead to HF are coronary artery disease, myocardial infarction, valve disorders, high blood pressure, and cardiomyopathy. Due to the limited regenerative capacity of the heart, the only curative therapy currently available is heart transplantation. Therefore, there is a great need for the development of novel regenerative strategies to repair the injured myocardium, replace damaged valves, and treat occluded coronary arteries. Recent advances in manufacturing technologies have resulted in the precise fabrication of 3D fiber scaffolds with high architectural control that can support and guide new tissue growth, opening exciting new avenues for repair of the human heart. This review discusses the recent advancements in the novel research field of fiber patterning manufacturing technologies for cardiac tissue engineering (cTE) and to what extent these technologies could meet the requirements of the highly organized and structured cardiac tissues. Additionally, future directions of these novel fiber patterning technologies, designs, and applicability to advance cTE are presented.

Coronary Artery Disease: From Mechanism to Clinical Practice

In most developed countries, coronary artery disease (CAD), mostly caused by atherosclerosis of coronary arteries, is one of the primary causes of death. From 1990s to 2000s, mortality caused by acute MI declined up to 50%. The incidence of CAD is related with age, gender, economic, etc. Atherosclerosis contains some highly correlative processes such as lipid disturbances, thrombosis, inflammation, vascular smooth cell activation, remodeling, platelet activation, endothelial dysfunction, oxidative stress, altered matrix metabolism, and genetic factors. Risk factors of CAD exist among many individuals of the general population, which includes hypertension, lipids and lipoproteins metabolism disturbances, diabetes mellitus, chronic kidney disease, age, genders, lifestyle, cigarette smoking, diet, obesity, and family history. Angina pectoris is caused by myocardial ischemia in the main expression of pain in the chest or adjoining area, which is usually a result of exertion and related to myocardial function disorder. Typical angina pectoris would last for minutes with gradual exacerbation. Rest, sit, or stop walking are the usual preference for patients with angina, and reaching the maximum intensity in seconds is uncommon. Rest or nitroglycerin usage can relieve typical angina pectoris within minutes. So far, a widely accepted angina pectoris severity grading system included CCS (Canadian Cardiovascular Society) classification, Califf score, and Goldman scale. Patients with ST-segment elevated myocardial infarction (STEMI) may have different symptoms and signs of both severe angina pectoris and various complications. The combination of rising usage of sensitive MI biomarkers and precise imaging techniques, including electrocardiograph (ECG), computed tomography, and cardiac magnetic resonance imaging, made the new MI criteria necessary. Complications of acute myocardial infarction include left ventricular dysfunction, cardiogenic shock, structural complications, arrhythmia, recurrent chest discomfort, recurrent ischemia and infarction, pericardial effusion, pericarditis, post-myocardial infarction syndrome, venous thrombosis pulmonary embolism, left ventricular aneurysm, left ventricular thrombus, and arterial embolism.

Proteomic analysis of decellularized pancreatic matrix identifies collagen V as a critical regulator for islet organogenesis from human pluripotent stem cells

In pancreatic tissue engineering, generating human pancreatic islet organoids from stem cells has been challenging due mainly to a poor understanding of niches required for multicellular tissue self-assembly in vitro. In this study, we aimed to identify bioactive, chemically defined niches from natural, biological materials for islet development in vitro. We investigated the proteomics of decellularized rat pancreatic extracellular matrix (dpECM) hydrogel using advanced bioinformatics analysis, and identified that type V collagen (ColV) is constantly and abundantly present in dpECM hydrogel. Niches provided to human pluripotent stem cells (iPSCs) by presenting ColV in matrix coating substrates permitted stem cells progression into islet-like organoids that consist of all major pancreatic endocrine cell types, i.e. α, β, δ, and pancreatic polypeptide cells. In the presence of ColV niches, gene expressions of all key pancreatic transcription factors and major hormone genes significantly increased in iPSC-derived organoids. Most importantly, ColV-containing microenvironment resulted in enhanced glucose responsive secretions of both insulin and glucagon hormone from organoids. The study demonstrates that ColV is a critical regulator that augments islet self-assembly from iPSCs, and it is feasible to utilize natural biomaterials to build tissue cues essential for multicellular tissue production in vitro.

Vascular smooth muscle cells in atherosclerosis

Vascular smooth muscle cells (VSMCs) are a major cell type present at all stages of an atherosclerotic plaque. According to the 'response to injury' and 'vulnerable plaque' hypotheses, contractile VSMCs recruited from the media undergo phenotypic conversion to proliferative synthetic cells that generate extracellular matrix to form the fibrous cap and hence stabilize plaques. However, lineage-tracing studies have highlighted flaws in the interpretation of former studies, revealing that these studies had underestimated both the content and functions of VSMCs in plaques and have thus challenged our view on the role of VSMCs in atherosclerosis. VSMCs are more plastic than previously recognized and can adopt alternative phenotypes, including phenotypes resembling foam cells, macrophages, mesenchymal stem cells and osteochondrogenic cells, which could contribute both positively and negatively to disease progression. In this Review, we present the evidence for VSMC plasticity and summarize the roles of VSMCs and VSMC-derived cells in atherosclerotic plaque development and progression. Correct attribution and spatiotemporal resolution of clinically beneficial and detrimental processes will underpin the success of any therapeutic intervention aimed at VSMCs and their derivatives.

Rutin promotes the formation and osteogenic differentiation of human periodontal ligament stem cell sheets in vitro

Cell sheet technology is a novel tissue engineering technology that has been rapidly developed in recent years. As a novel technology, cell sheet technology is expected to become one of the preferred methods for cell transplantation. The present study investigated the biological effects of rutin on the formation of periodontal ligament stem cell (PDLSC) sheets and their resultant osteogenic properties. The results of Cell Counting Kit-8 (CCK-8) assay demonstrated that a concentration of 1×10⁻⁶ mol/l rutin promoted the proliferation of PDLSCs more effectively compared with other designed concentrations. Rutin-modified cell sheets could be induced by complete medium supplemented with 20 µg/ml vitamin C (VC) and 1×10⁻⁶ mol/l rutin. Rutin-modified cell sheets appeared thicker and more compact compared with the VC-induced PDLSC sheets, demonstrating more layers of cells (3 or 4 layers), which secreted a richer extracellular matrix (ECM). Furthermore, the improved cell sheets exhibited varying degrees of increases in the mRNA and protein expression of collagen type I (COL1), alkaline phosphatase (ALP), runt-related transcription factor 2 (RUNX2) and osteopontin (OPN). Combined treatment with VC and rutin promoted the formation of PDLSC sheets and enhanced the osteogenic differentiation potential of the cell sheets. Therefore, rutin-modified cell sheets of PDLSCs are expected to play an important role in the treatment of periodontal tissue regeneration by stem cells.

Nano-mechanical mapping of interdependent cell and ECM mechanics by AFM force spectroscopy

Extracellular matrix (ECM), as a dynamic component of the tissue, influences cell behavior and plays an important role in cell mechanics and tissue homeostasis. Reciprocally, this three-dimensional scaffold is dynamically, structurally and mechanically modified by cells. In the field of biophysics, the independent role of cell and ECM mechanics has been largely investigated; however, there is a lack of experimental data reporting the interdependent interplay between cell and ECM mechanics, measured simultaneously. Here, using Atomic Force Microscopy (AFM) we have characterized five different decellularized matrices diverse in their topography, ECM composition and stiffness and cultured them with normal and pathological fibroblasts (scar and Dupuytren's). We investigated the change in topography and elasticity of these matrices due to cell seeding, by using AFM peak force imaging and mechanical mapping, respectively. We found normal fibroblasts soften these matrices more than pathological fibroblasts, suggesting that pathological fibroblasts are profoundly influencing tissue stiffening in fibrosis. We detected different ECM composition of decellularized matrices used here influences fibroblast stiffness, thus highlighting that cell mechanics not only depends on ECM stiffness but also on their composition. We used confocal microscopy to assess fibroblasts invasion and found pathological fibroblasts were invading the matrices deeper than normal fibroblasts.

Association of TATA box-binding protein-associated factor RNA polymerase I subunit C (TAF1C) with T2DM

Proteins differential expression in type 2 diabetes mellitus (T2DM) can be due to etiological factors or pathological changes, such proteins can be utilized as biomarkers. Identification of a marker protein out of thousands became a feasible task during the proteomics era by using liquid chromatography-tandem mass spectrometry (LC-MS/MS). In this study, blood samples were obtained from 80 Bahraini subjects with and without T2DM, a subset was used for proteomic analysis by LC-MS/MS, while all samples were used for ELISA analysis of 3 proteins, TATA-box binding protein-associated factor RNA polymerase-1-C (TAF1C), ceruloplasmin (CERP) and fibronectin (FN). The former 2 proteins were selected from the T2DM-protein-panel identified by LC-MS/MS, and the latter was analyzed for validation of the setting. The main findings of the proteomic analysis are i. Identifications of 62 differentially expressed proteins in T2DM, ii. Upregulation of 71% of the identified proteins. While the ELISA analysis showed that; both TAF1C and FN were significantly increased in T2DM (P0.015 and P0.001, respectively), while CERP was not (P0.088). Logistic regression analysis: i. confirmed the above associations after correction for covariates, ii. Revealed an interaction between age and gender that affect the association of the proteins with T2DM. In conclusion, knowing that TAF1C is a prerequisite in ribosomal biogenesis, our ELISA results are suggestive of increased protein synthesis in T2DM, explaining the observed upregulation of the proteins identified by LC-MSMS. The association between T2DM and TAF1C is a novel finding that might open a new avenue in DM research.

Arterial Remodeling and Dysfunction in the ZSF1 Rat Model of Heart Failure With Preserved Ejection Fraction

BACKGROUND

The interplay between the stiffened heart and vessels has long been viewed as a core mechanism in heart failure with preserved ejection fraction, but the incremental vascular molecular remodeling mechanisms from systemic arterial hypertension to heart failure with preserved ejection fraction remain poorly investigated. Our aim was to characterize central arterial remodeling and dysfunction in ZSF1 obese rats and to compare it with hypertensive ZSF1 lean and healthy Wistar-Kyoto controls.

METHODS AND RESULTS

Twenty-week-old male ZSF1 obese (n=9), lean (n=9), and Wistar-Kyoto rats (n=9) underwent left ventricular pressure-volume loop evaluation and synchronous acquisition of ascending aortic flow and pressure. Aortic rings underwent functional evaluation, histology, and molecular biology studies. Although mean arterial pressure, characteristic aortic impedance, and reactivity to phenylephrine were similarly increased in hypertensive ZSF1 lean and obese, only ZSF1 obese showed impaired relaxation and upward-shifted end-diastolic pressure-volume relationships despite preserved systolic function indexes, denoting heart failure with preserved ejection fraction. ZSF1 obese phenotype further showed decreased aortic compliance, increased wave reflection, and impaired direct NO donor and endothelial-mediated vasodilation which were accompanied on structural and molecular grounds by aortic media thickening, higher collagen content and collagen/elastin ratio, increased fibronectin and α-5 integrin protein expression and upregulated TGF (transforming growth factor)-β and CTGF (connective tissue growth factor) levels.

CONCLUSIONS

Functional, molecular, and structural disturbances of central vessels and their potentially underlying pathways were newly characterized in experimental heart failure with preserved ejection fraction rendering the ZSF1 obese rat model suitable for preclinical testing.

Hyaluronic Acid Nanoparticle Composite Films Confer Favorable Time-Dependent Biofunctions for Vascular Wound Healing

Vascular stent implantation is the primary treatment for coronary artery disease. Surface modification of coronary stents is a topic of interest to prevent thrombosis and restenosis and to promote endothelization. However, bioactive coatings on implants have not yet been fully developed for the time-ordered biological requirements of vascular stents. The first month after vascular stent implantation, the pathological changes in the injured vascular tissue are complex and time-ordered. Therefore, vascular stents possess time-dependent biofunctions with early phase anticoagulant and anti-inflammatory properties. In the later stage, inhibitory effects on smooth muscle cell proliferation and the promotion of endothelial cell adhesion might meet the requirements of vascular repair. We fabricated three types of hyaluronic acid nanoparticles (HA-NPs) by subjecting HA and poly(ether imide) to ethyl(dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide coupling reaction. The HA-NPs prepared by HA with a molecular weight of 100 kDa showed the best stability in a hyaluronidase environment. HA-NP composite films (HA-NCFs) were then fabricated by coimmobilizing selected HA-NPs (100 kDa) and HA molecules (100 kDa) through amide reaction on PDA/HD coated 316 L stainless steel surfaces. The detachment behavior of HA-NPs (100 kDa) in PBS for 20 days indicated that the HA-NPs (100 kDa) gradually detached from the surface. In vitro tests (anticoagulant and anti-inflammatory tests, endothelial cells, and smooth muscle cells seeding, and bacterial adhesion test) indicated that the newly fabricated HA-NCFs have inhibitory effects on the adhesion of fibrinogen, platelets, macrophages, bacteria, SMCs, and ECs. As the HA-NPs detached from the surface, the HA-NCFs showed excellent gradual comprehensive biocompatibility, which promoted adhesion and proliferation of ECs while still exerting inhibitory effects on the platelets, macrophages, and SMCs. Finally, in vivo SS wire implantation test (aortic implantation in healthy Sprague-Dawley rats) showed that HA-NCFs possessed anti-inflammatory properties, inhibited the proliferation of smooth muscle cells, and promoted re-endothelialization. In particular, HA-NCFs with time-dependent biofunctions showed better antirestenosis effects than those of surfaces modified with molecular HA, which exhibited constant biocompatibility. This study provides an important basis for the construction of HA-NP composite films with favorable time-dependent biofunctions for the time-ordered biological requirements of vascular stent.

Emerging regulators of vascular smooth muscle cell migration

Vascular smooth muscle cells (VSMCs) are the predominant cell type in the blood vessel wall and normally adopt a quiescent, contractile phenotype. VSMC migration is tightly controlled, however, disease associated changes in the soluble and insoluble environment promote VSMC migration. Classically, studies investigating VSMC migration have described the influence of soluble factors. Emerging data has highlighted the importance of insoluble factors, including extracellular matrix stiffness and porosity. In this review, we will recap on the important signalling pathways that regulate VSMC migration and reflect on the potential importance of emerging regulators of VSMC function.

Layer-by-layer assembly of nanofilms to control cell functions

Control of cell functions by layer-by-layer assembly has a great challenge in tissue engineering and biomedical applications. We summarize current hot approaches in this review.

Potential injurious effects of the fine particulate PM2.5 on the progression of atherosclerosis in apoE-deficient mice by activating platelets and leukocytes

INTRODUCTION

Exposure to the fine particulate matter PM2.5 is strongly associated with atherosclerotic diseases, creating considerable public concern. Nevertheless, the mechanisms have not been fully elucidated. We exposed atherosclerosis-prone apoE-deficient mice to PM2.5 to begin investigating these mechanisms.

MATERIAL AND METHODS

Thirty-two 8-week-old male apoE^-/- mice were divided to two groups fed with high-fat diet: a control group instilled with 0.9% saline, and an experimental group instilled with PM2.5 (30 mg/kg/day) for 8 weeks. We measured PM2.5 in whole blood by the ICP-MS method, and lipids and inflammatory factors by standard methods. The whole descending arteries were stained with oil red O; Aortic roots were stained with Movat, Sirius Red and immunohistochemical stains for pathological analysis; Brachiocephalic arteries for scanning electron microscopy, the descending arteries for Q-PCR. Echocardiography was used to evaluate cardiac function.

RESULTS

In PM2.5 group, we observed elevated heavy metal components, consistent with higher amounts of platelets in total blood. The PM2.5 group also had elevated serum inflammatory factor levels. Finally, the PM2.5 group showed larger atherosclerotic plaques (p = 0.0231), higher numbers of lesion macrophages (p = 0.0183), greater injury to endothelial layers with greater adherence of platelets and leukocytes, elevated inflammatory factor levels, the NAD(P)H oxidase subunits p22phox and p47phox (p = 0.0079 and p = 0.0294), the M1/M2 associated markers IL-6, TNF-α (p = 0.0291, p = 0.0286), iNOS, IL-12 (p = 0.0122 and p = 0.0280) and arginase-1, and CD206 (p = 0.0216 and p = 0.0317).

CONCLUSIONS

PM2.5 exposure activated circulating leukocytes, platelets and associated inflammatory factors, contributing to the progression of atherosclerosis in apoE^-/- mice.

A Review of Integrin-Mediated Endothelial Cell Phenotype in the Design of Cardiovascular Devices

Sustained biomaterial thromboresistance has long been a goal and challenge in blood-contacting device design. Endothelialization is one of the most successful strategies to achieve long-term thromboresistance of blood-contacting devices, with the endothelial cell layer providing dynamic hemostatic regulation. It is well established that endothelial cell behavior is influenced by interactions with the underlying extracellular matrix (ECM). Numerous researchers have sought to exploit these interactions to generate improved blood-contacting devices by investigating the expression of hemostatic regulators in endothelial cells on various ECM coatings. The ability to select substrates that promote endothelial cell-mediated thromboresistance is crucial to advancing material design strategies to improve cardiovascular device outcomes. This review provides an overview of endothelial cell regulation of hemostasis, the major components found within the cardiovascular basal lamina, and the interactions of endothelial cells with prominent ECM components of the basement membrane. A summary of ECM-mimetic strategies used in cardiovascular devices is provided with a focus on the effects of key adhesion modalities on endothelial cell regulators of hemostasis.

Synergistic effect of PCPE1 and sFRP2 on the processing of procollagens via BMP1

Procollagen processing is essential for organ development and tissue functions. Both procollagen C-proteinase enhancer 1 (PCPE1) and secreted frizzled-related protein 2 (sFRP2) play vital roles in collagen formation via regulating the procollagen C-proteinase activity of bone morphogenetic protein 1 (BMP1). However, whether the two proteins exert a synergistic effect on BMP1 activity remains unclear. Here, simultaneous knockdown of sFRP2 and PCPE1 led to less collagen formation in mouse embryonic fibroblasts and dorsalized phenotypes in zebrafish embryos. Further studies revealed a direct interaction between the Frizzled domain of sFRP2 and the complement/Uegf/BMP-1 domain of PCPE1, which enhances the cleavage activity of BMP1 on procollagen. These results suggest that double silencing of sFRP2 and PCPE1 may provide a strategy for treating fibrosis diseases caused by collagen deposition.

Caring for cells in microsystems: principles and practices of cell-safe device design and operation

Microfluidic device designers and users continually question whether cells are 'happy' in a given microsystem or whether they are perturbed by micro-scale technologies. This issue is normally brought up by engineers building platforms, or by external reviewers (academic or commercial) comparing multiple technological approaches to a problem. Microsystems can apply combinations of biophysical and biochemical stimuli that, although essential to device operation, may damage cells in complex ways. However, assays to assess the impact of microsystems upon cells have been challenging to conduct and have led to subjective interpretation and evaluation of cell stressors, hampering development and adoption of microsystems. To this end, we introduce a framework that defines cell health, describes how device stimuli may stress cells, and contrasts approaches to measure cell stress. Importantly, we provide practical guidelines regarding device design and operation to minimize cell stress, and recommend a minimal set of quantitative assays that will enable standardization in the assessment of cell health in diverse devices. We anticipate that as microsystem designers, reviewers, and end-users enforce such guidelines, we as a community can create a set of essential principles that will further the adoption of such technologies in clinical, translational and commercial applications.