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The vasculature is crucial for tissue development and survival, and the stability of blood vessels to perform these functions relies on the interplay between endothelial cells (ECs) and mural cells. Pericytes are a subtype of mural cells found in the microvasculature that extend their processes to wrap around the endothelial monolayer. Pericytes are recruited during vessel growth through the excretion of soluble factors from ECs where they stabilize angiogenic sprouts and induce maturation of the resident cells. Alterations in these interactions between ECs and pericytes are associated with aberrant vessel growth and disrupted vasculature function characteristic of numerous diseases. Therefore, deeper understanding of the cross-talk between these cell types has numerous implications for understanding morphogenesis and elucidating disease mechanisms. In this review, we highlight recent advances and current trends studying the interactions between ECs and pericytes in vitro. We begin by analyzing three-dimensional hydrogel platforms that mimic the tissue extracellular matrix to investigate signaling pathways and altered vascular function in disease-specific cells. We next examine how microfluidic vasculature-on-a-chip platforms have elucidated the interplay of these vascular cells during angiogenesis and vascular network formation under controlled physiochemical cues and interstitial flow. Additionally, studies have utilized microvessels to measure the effect of shear stress on barrier function through the control of luminal flow and the impact of inflammation on these vascular cell interactions. Finally, we briefly highlight self-assembling human blood vessel organoids, an emerging high-throughput platform to study ECs and pericyte interactions.

The placenta mediates transport of nutrients, such as inorganic phosphate (Pi), between the maternal and fetal circulatory systems. The placenta itself also requires high levels of nutrient uptake as it develops, to provide critical support for fetal development. This study aimed to determine placental Pi transport mechanisms using in vitro and in vivo models. We observed that Pi (P33) uptake in BeWo cells is sodium-dependent, and that SLC20A1/Slc20a1 is the most highly expressed placental sodium-dependent transporter in mouse (microarray) and human cell line (RT-PCR) and term placenta (RNA-seq), supporting that normal growth and maintenance of the mouse and human placenta requires SLC20A1/Slc20a1. Slc20a1 wildtype (Slc20a1+/+) and knockout (Slc20a1-/-) mice were produced through timed intercrosses, and displayed yolk sac (YS) angiogenesis failure as expected at E10.5. E9.5 tissues were analyzed to test whether placental morphogenesis requires Slc20a1. At E9.5 the developing placenta was reduced in size in Slc20a1-/-. Multiple structural abnormalities were also observed in the Slc20a1-/- chorioallantois. We determined that MCT1+ cells were reduced in developing Slc20a1-/- placenta, confirming that Slc20a1 loss reduced trophoblast syncytiotrophoblast 1 (SynT-I) coverage. Next, we examined cell type-specific Slc20a1 expression and SynT molecular pathways in silico, and identified Notch/Wnt as a pathway of interest that regulates trophoblast differentiation. We further observed that specific trophoblast lineage express Notch/Wnt genes that associate with endothelial cell tip-and-stalk cell markers. In conclusion, our findings support that Slc20a1 mediates symport of Pi into SynT cells, providing critical support for their differentiation and angiogenic mimicry function at the developing maternal-fetal interface.

Platelets have a pivotal role in maintaining cardiovascular homeostasis. They are kept docile by endothelial-derived mediators. Aberration in haemostatic balance predisposes an individual to an elevated risk of a prothrombotic environment. Anti-platelet therapy has been a key component to reduce this risk. However, understanding how these medications affect the balance between the activation and inhibition of platelets is critical. There is no evidence that a key anti-platelet therapy – aspirin, may not be the most efficacious medicine of choice, as it can compromise both platelet inhibition and activation pathways. In this review, the rationale of aspirin as an anti-thrombotic drug has been critically discussed. This review looks at how recently published trials are raising key questions about the efficacy and safety of aspirin in countering cardiovascular diseases. There is an increasing portfolio of evidence that identifies that although aspirin is a very cheap and accessible drug, it may be used in a manner that is not always beneficial to a patient, and a more nuanced and targeted use of aspirin may increase its clinical benefit and maximize patient response. The questions about the use of aspirin raise the potential for changes in its clinical use for dual anti-platelet therapy. This highlights the need to ensure that treatment is targeted in the most effective manner and that other anti-platelet therapies may well be more efficacious and beneficial for CVD patients in their standard and personalized approaches.

Remodelling of cell–cell junctions is crucial for proper tissue development and barrier function. The cadherin-based adherens junctions anchor via β-catenin and α-catenin to the actomyosin cytoskeleton, together forming a junctional mechanotransduction complex. Tension-induced conformational changes in the mechanosensitive α-catenin protein induce junctional vinculin recruitment. In endothelial cells, vinculin protects the remodelling of VE–cadherin junctions. In this study, we have addressed the role of vinculin in endothelial barrier function in the developing vasculature. In vitro experiments, using endothelial cells in which α-catenin was replaced by a vinculin-binding-deficient mutant, showed that junctional recruitment of vinculin promotes endothelial barrier function. To assess the role of vinculin within blood vessels in vivo, we next investigated barrier function in the vasculature of vcl knockout zebrafish. In the absence of vinculin, sprouting angiogenesis and vessel perfusion still occurred. Intriguingly, the absence of vinculin made the blood vessels more permeable for 10 kDa dextran molecules but not for larger tracers. Taken together, our findings demonstrate that vinculin strengthens the endothelial barrier and prevents vascular leakage in developing vessels.

Arterial stiffening is a hallmark of aging and cardiovascular disease. While it is well established that vascular smooth muscle cells (SMCs) contribute to arterial stiffness by synthesizing and remodeling the arterial extracellular matrix, the direct contributions of SMC contractility and mechanosensors to arterial stiffness, and particularly the arterial response to pressure, remain less well understood despite being a long-standing question of biomedical importance. Here, we have examined this issue by combining the use of pressure myography of intact carotid arteries, pharmacologic inhibition of contractility, and genetic deletion of SMC focal adhesion kinase (FAK). Biaxial inflation-extension tests performed at physiological pressures showed that acute inhibition of cell contractility with blebbistatin or EGTA altered vessel geometry and preferentially reduced circumferential, as opposed to axial, arterial stiffness in wild-type mice. Similarly, genetic deletion of SMC FAK, which attenuated arterial contraction to KCl, reduced vessel wall thickness and circumferential arterial stiffness in response to pressure while having minimal effect on axial mechanics. Moreover, these effects of FAK deletion were lost by treating arteries with blebbistatin or by inhibiting myosin light-chain kinase. The expression of arterial fibrillar collagens, the integrity of arterial elastin, or markers of SMC differentiation were not affected by the deletion of SMC FAK. Our results connect cell contractility and SMC FAK to the regulation of arterial wall thickness and directionally specific arterial stiffening.

Marfan syndrome (MFS) is a connective tissue disorder causing aortic aneurysm formation. Currently, only prophylactic aortic surgery and blood pressure-lowering drugs are available to reduce the risk of aortic rupture. Upon whole genome sequencing of a Marfan family, we identified a complement gene C1R variant (p.Ser152Leu), which is associated with severe aortic patients. Therefore, we assessed the role of complement activation in MFS aortic tissue. Expression of various complement genes and proteins was detected in human and murine MFS aneurysm tissue, which prompted us to study complement inhibition in MFS mice. Treatment of the Fbn1 ^C1041G/+ MFS mice with human plasma-derived C1-esterase inhibitor Cetor® resulted in reduced complement deposition, decreased macrophage influx in the aorta, and lower circulating TNFα levels. However, in line with previous anti-inflammatory treatments, complement inhibition did not change the aortic dilatation rate in this MFS mouse model. Thus, while complement factors/component 3 activation were detected in human/murine MFS aorta, Cetor® had no effect on aortic dilatation in MFS mice, indicating that complement inhibition is not a suitable treatment strategy in MFS.

The emergence of the organoid simulates the native organs and this mini organ offers an excellent platform for probing multicellular interaction, disease modeling and drug discovery. Blood vessels constitute the instructive vascular niche which is indispensable for organ development, function and regeneration. Therefore, it is expected that the introduction of infiltrated blood vessels into the organoid might further pump vitality and credibility into the system. While the field is emerging and growing with new concepts and methodologies, this review aims at presenting various sources of vascular ingredients for constructing vascularized organoids and the paired methodology including de- and recellularization, bioprinting and microfluidics. Representative vascular organoids corresponding to specific tissues are also summarized and discussed to elaborate on the next generation of organoid development.

The present study aimed to assess the role of urocortin II (UII) in the process of vascular calcification in vitro by using a calcification model, to detect the changes in the mRNA and protein levels of associated markers in rat adventitial fibroblasts (AFs) during their phenotypic transformation to osteoblast cellsto clarify the main signal transduction pathway of UII responsible for regulating vascular calcification and AF phenotypic transformation of osteoblast cells, and to prove that UII was an endogenous factor promoting vascular calcification, so as to provide an effective experimental basis for the clinical regulation of related diseases caused by vascular calcification. Finally, we successfully constructed the calcified cell model, found that UII was an endogenous substance regulating vascular calcification, regulated the vascular calcification by promoting apoptosis and inhibiting autophagy through up- and downregulated BAX and BCL-2/BECLIN 1 (BECN1) level, and the Wnt/β-catenin signaling pathway was involved.

Atherosclerosis is characterised by abnormal lipid and cell accumulation within arterial layers that leads to disturbed blood flow. Modified cholesterol forms such as oxidised low-density lipoprotein (oxLDL) enter cells altering their phenotype, triggering over-exuberant repair and arterial occlusion, myocardial infarction or stroke. We hypothesised that oxLDL enters vascular wall cells and induces interleukin-1β (IL-1β) secretion, potentially via a caspase-1/NLRP3 mechanism. Human coronary artery endothelial cells (HCAEC) and smooth muscle cells (HCASMC), isolated from different donors, were cultured and stimulated (primed) with pro-inflammatory cytokines TNFα and IL-1α (10 ng/mL each, for 48 h), followed by incubation with human oxLDL (10–50 ug/mL) for up to 6 h. Inhibitors of caspase-1 (YVAD), NLRP3 (MCC950) and gasdermin D (disulfiram) were added 1 h before oxLDL. Cell lysates and culture supernatants were collected and analysed for IL-1β using ELISA. Microscopy imaging showed oxLDL entered stimulated cells and formed particles. OxLDL at 20 and 50 ug/mL induced the maximum release of IL-1β from stimulated HCASMCs and HCAECs, respectively, compared to control. Inhibition of either NLRP3, caspase-1 or gasdermin D significantly reduced the release of IL-1β (4-fold, P < 0.0001; 14-fold, P < 0.0001, 1.5-fold, P < 0.0003, respectively) in HCAEC. In contrast, in HCASMCs, only caspase-1 inhibition reduced the release of IL-1β (2.1-fold, P < 0.0001). HCAECs and HCASMCs elicited the release of IL-1β in response to the same stimulus via different mechanisms. In HCAECs, released IL-1β potentially exits via a GSDMD-induced membrane pore. These data suggest that caspase-1 or gasdermin D inhibition is likely to be effective vessel wall cell-specific strategies for the reduction of atherosclerosis.