PECAM-1 Expression Research Articles

Leukemia Inhibitory Factor Receptor inhibition by EC359 reduces atherosclerotic stenosis grade in Ldlr-/- mice

Cytokines are involved in all stages of atherosclerosis, generally contributing to disease progression. Previously, members of the IL-6 cytokine family, such as Interleukin-6, oncostatin M, and cardiotrophin-1, have been extensively studied in atherosclerosis. However, the role of leukemia inhibitory factor (LIF), member of the IL-6 family, and its receptor (LIFR), remains to be further elucidated. Therefore, the aim of this study is to provide insight in LIF receptor signalling in atherosclerosis development.Single-cell RNA sequencing analysis of human carotid artery plaques revealed that mast cells highly express LIF, whereas LIFR was specifically expressed on activated endothelial cells. A similar expression pattern of Lifr was observed in mouse atherosclerotic plaques. Next, female Western-type diet fed Ldlr-/- mice were treated with LIF receptor inhibitor EC359 (5 mg/kg s.c., n=15) or control solvent (n=15) three times per week for eight weeks. Stenosis grade was reduced in the aortic root of EC359 treated mice compared to control mice, but treatment did not affect plaque composition. Serum cholesterol levels were significantly reduced in EC359 treated mice, likely attributed to a reduction in VLDL cholesterol levels. Furthermore, LIF receptor inhibition reduced Pecam1 and Vcam1 expression in the aorta. Consequently, immune cell infiltration was reduced in aortic plaques of EC359 treated mice compared to control mice.Conclusively, we demonstrated that LIF receptor is a potential therapeutic target in atherosclerosis by reducing plaque size, attributed to lower serum cholesterol levels, reduced endothelial activation and less immune cell infiltration in the plaque.

Effects of Panax notoginseng saponins on alleviating low shear induced endothelial inflammation and thrombosis via Piezo1 signalling

Ethnopharmacological relevancePanax notoginseng saponins (PNS) are the major effective components of Panax notoginseng (burk) F.H.Chen which is one of the classic promoting blood circulation herbs in traditional Chinese medicine. PNS is widely used in China for the treatment of cerebral ischemic stroke. Pathological low shear stress is a causal factor in endothelial inflammation and thrombosis. However, the mechanism of PNS against low shear related endothelial inflammation is still unclear. Aim to the studyThis study aims to investigate the effects of PNS against endothelial inflammation induced by low shear stress and to explore the underlying mechanical and biological mechanisms. Materials and methodsMouse model of carotid partial ligation for inducing low endothelial shear stress was established, the pharmacodynamic effect and mechanism of PNS against endothelial inflammation induced by low shear stress through Piezo1 were explored. Yoda1-evoked Piezo1 activation and expression in human umbilical vein endothelial cells (HUVECs) were determined at static condition. Microfluidic channel systems were used to apply shear stress on HUVECs and Piezo1 siRNA HUVECs to determine PECAM-1, p-YAP and VCAM-1 expression. And platelet rich plasma (PRP) was introduced to low shear treated endothelial cells surface to observe the adhesion and activation by fluorescence imaging and flowcytometry. ResultsPNS attenuated endothelial inflammation and improved blood flow in a reasonable dose response pattern in carotid partial ligation mouse model by influencing Piezo1 and PECAM-1 expression, while suppressing yes-associated protein (YAP) nuclear translocation. We found Piezo1 sensed abnormal shear stress and transduced these mechanical signals by different pathways in HUVECs, and PNS relieved endothelial inflammation induced by low shear stress through Piezo1. We also found Piezo1 signalling has interaction with PECAM-1 under low shear stress, which were involved in platelets adhesion to endothelial cells. Low shear stress increased YAP nuclear translocation and increased VCAM-1 expression in HUVECs which might activate platelets. PNS inhibited low shear induced Piezo1 and PECAM-1 expression and YAP nuclear translocation in HUVECs, furthermore inhibited platelet adhesion and activation on dysfunctional endothelial cells induced by low shear stress. ConclusionPNS ameliorated endothelial inflammation and thrombosis induced by low shear stress through modulation of the Piezo1 channel, PECAM-1 expression, and YAP nuclear translocation. PNS might serve as a potential therapeutic candidate for ameliorating endothelial inflammation induced by abnormal blood shear stress.

Transient heat stress protects from severe endothelial damage and dysfunction during prolonged experimental ex-vivo lung perfusion.

The pulmonary endothelium is the primary target of lung ischemia-reperfusion injury leading to primary graft dysfunction after lung transplantation. We hypothesized that treating damaged rat lungs by a transient heat stress during ex-vivo lung perfusion (EVLP) to elicit a pulmonary heat shock response could protect the endothelium from severe reperfusion injury. Rat lungs damaged by 1h warm ischemia were reperfused on an EVLP platform for up to 6h at a constant temperature (T°) of 37°C (EVLP37°C group), or following a transient heat stress (HS) at 41.5°C from 1 to 1.5h of EVLP (EVLPHS group). A group of lungs exposed to 1h EVLP only (pre-heating conditions) was added as control (Baseline group). In a first protocol, we measured lung heat sock protein expression (HSP70, HSP27 and Hsc70) at selected time-points (n=5/group at each time). In a second protocol, we determined (n=5/group) lung weight gain (edema), pulmonary compliance, oxygenation capacity, pulmonary artery pressure (PAP) and vascular resistance (PVR), the expression of PECAM-1 (CD31) and phosphorylation status of Src-kinase and VE-cadherin in lung tissue, as well as the release in perfusate of cytokines (TNFα, IL-1β) and endothelial biomarkers (sPECAM, von Willebrand Factor -vWF-, sE-selectin and sICAM-1). Histological and immunofluorescent studies assessed perivascular edema and formation of 3-nitrotyrosine (a marker of peroxinitrite) in CD31 lung endothelium. HS induced an early (3h) and persisting expression of HSP70 and HSP27, without influencing Hsc70. Lungs from the EVLP37°C group developed massive edema, low compliance and oxygenation, elevated PAP and PVR, substantial release of TNFα, IL-1β, s-PECAM, vWF, E-selectin and s-ICAM, as well as significant Src-kinase activation, VE-cadherin phosphorylation, endothelial 3-NT formation and reduced CD31 expression. In marked contrast, all these alterations were either abrogated or significantly attenuated by HS treatment. The therapeutic application of a transient heat stress during EVLP of damaged rat lungs reduces endothelial permeability, attenuates pulmonary vasoconstriction, prevents src-kinase activation and VE-cadherin phosphorylation, while reducing endothelial peroxinitrite generation and the release of cytokines and endothelial biomarkers. Collectively, these data demonstrate that therapeutic heat stress may represent a promising strategy to protect the lung endothelium from severe reperfusion injury.

Abstract 105: Neutrophil Cracr2a Is Crucial For Calcium Signaling And Enhances Neutrophil Adhesive Function Under Thromboinflammatory Conditions

Ca 2+ release-activated channel regulator 2A (CRACR2A) is a Ca 2+ -binding protein that facilitates store-operated Ca 2+ entry during T cell activation. However, it is unknown whether neutrophil CRACR2A regulates neutrophil functions in inflammation. Our confocal intravital microscopy (IVM) revealed that compared to wild-type (WT) mice, myeloid-specific cracr2a conditional knockout (CKO, cracr2a fl/fl;Lyz-cre ) mice exhibited a significant increase in neutrophil rolling and a decrease in neutrophil adhesion, crawling, and transmigration on ear and cremaster venules in TNF-α-induced inflammation. Deletion of neutrophil cracr2a impaired β2 integrin function without affecting the expression of L-selectin, PECAM-1, and JAM-A. Neutrophil cracr2a increased Ca 2+ mobilization after stimulation with fMLP, A23187, and thapsigargin by its rapid interaction with STIM1. Due to the lack of CRACR2A inhibitors, we generated CRACR2A-deleted HL60 cells using CRISPR/Cas9. CRACR2A deletion in differentiated HL60 cells recapitulated the defects seen in cracr2a-null neutrophils, including reduced β2 integrin function and Ca 2+ mobilization after agonist stimulation. Since excessively recruited neutrophils cause brain damage in ischemic stroke, we examined whether neutrophil cracr2a contributes to stroke pathology. Using a transient middle cerebral artery occlusion (tMCAO)-induced ischemic stroke model, we found that compared to WT mice, cracr2a CKO mice exhibited improved neurological deficits and reduced infarct volume. Longitudinal 4D IVM of mouse brain revealed that neutrophil cracr2a is crucial for neutrophil adhesion and transmigration on cerebral vessels 16-24 hours after tMCAO and upregulated αMβ2 integrin on adherent neutrophils. Further, single-cell behavior analysis of 4D IVM showed that a proinflammatory subset of neutrophils arise in WT mice, but not cracr2a CKO mice, after tMCAO. We observed that the number of circulating pro-inflammatory neutrophils was markedly decreased 24 hours after tMCAO in cracr2a CKO mice compared with WT mice. Our findings indicate that neutrophil CRACR2A is a key regulator for Ca 2+ signaling and enhances neutrophil pro-inflammatory and adhesive activities in vascular inflammation and ischemic stroke.

Development of VEGF mimetic QK peptide on polycaprolactone nanofiber for vascular tissue engineering

Electrospinning allows promoting vascular tissue formation. Polycaprolactone (PCL) is a promising polymer for vascular tissue engineering because of its great mechanical strength and efficient fabrication. However, PCL shows limited biocompatibility owing to its hydrophobic structure. PCL nanofibers can be modified by peptides to improve biological activity. KLTWQELYQLKYKGI (QK) is a peptide that mimics the Vascular Endothelial Growth Factor (VEGF) by organizing endothelial cells. It is critically important to identify the optimum concentration of QK peptide conjugation onto PCL nanofiber for vascularization. Thus, PCL nanofibers were conjugated by different QK peptide concentrations (10 µM, 100 µM and 1000 µM). QK conjugated nanofibers were characterized by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) analysis. The vascularization was evaluated by Live and Dead staining assay, real time PCR of platelet/endothelial cell adhesion molecule (PECAM-1), VEGF and vascular endothelial-cadherin (VE-cadherin) genes and VEGF immunofluorescence analysis. The surfaces of PCL nanofibers were modified by different concentrations of QK peptide. The roughness of nanofibers increased depending on the increased concentration of QK peptide. The higher cell attachment and cell viability were observed in 1000 µM of QK peptide. 1000 µM of QK peptide showed higher vasculogenic potential in terms of PECAM, VEGF, and VE-cadherin gene expression than all the other experimental groups. In the same on gene expression analysis by qPCR, 1000 µM concentration of QK peptide showed the higher VEGF protein than the other experimental groups. 1000 µM concentration of QK peptide can be used to improve the vasculogenic property of PCL nanofibers.

Argon plasma-modified bacterial nanocellulose: Cell-specific differences in the interaction with fibroblasts and endothelial cells

Unique properties of bacterial nanocelullose (BNC), such as high purity, water retention, nanofibrillar structure and non-cytotoxicity, allow its application in regenerative medicine, particularly for active wound healing and for skin tissue engineering. However, its biological activity is not fully sufficient to be considered a good cell scaffold. This can be enhanced by physicochemical modifications, particularly plasma treatment. In this work, air-dried (AD) or lyophilized (L) BNC samples were modified in a direct current Ar+ plasma discharge (PM). BNC_AD samples showed higher surface roughness, tensile strength and Young's modulus but a lower swelling ratio than BNC_L samples. The swelling ratio of BNC_L samples further increased after PM. The samples were subjected to six-day in vitro cell culture tests with normal human dermal fibroblasts (NHDFs) or human umbilical vein endothelial cells (HUVECs), i.e. cell types important for skin defect healing. NHDFs adhered in higher numbers, by a larger cell spreading area and reached higher cell population densities on PM samples than on unmodified samples. However, in HUVECs, this effect of PM on cell growth was less pronounced or even opposite, especially on mechanically weaker and more swellable BNC_L. At the same time, both cell types preferred mechanically stronger BNC_AD for their adhesion and growth, which was more apparent in HUVECs. The expression of mRNA for markers of cell adhesion and phenotypic maturation in NHDFs (talin, vinculin, CD90) was generally similar on BNC_PM and on tissue culture polystyrene. In HUVECs, the expression of vinculin and PECAM-1 on all BNC samples was lower than on polystyrene, but the expression of KDR (VEGF receptor 2) was higher, especially on BNC_PM. These results indicate cell type-specific differences in the response to various BNC modifications, which must be properly balanced to accommodate various cell types needed for wound healing and skin tissue engineering.

Coronary microthrombi in the failing human heart: the role of von Willebrand factor and PECAM-1

The recognition of microthrombi in the heart microcirculation has recently emerged from studies in COVID-19 decedents. The present study investigated the ultrastructure of coronary microthrombi in heart failure (HF) due to cardiomyopathies that are unrelated to COVID-19 infection. In addition, we have investigated the role of von Willebrand factor (VWF) and PECAM-1 in microthrombus formation. We used electron microscopy to investigate the occurrence of microthrombi in patients with HF due to dilated (DCM, n = 7), inflammatory (MYO, n = 6) and ischemic (ICM, n = 7) cardiomyopathy and 4 control patients. VWF and PECAM-1 was studied by quantitative immunohistochemistry and Western blot. In comparison to control, the number of microthrombi was increased 7–9 times in HF. This was associated with a 3.5-fold increase in the number of Weibel–Palade bodies (WPb) in DCM and MYO compared to control. A fivefold increase in WPb in ICM was significantly different from control, DCM and MYO. In Western blot, VWF was increased twofold in DCM and MYO, and more than threefold in ICM. The difference between ICM and DCM and MYO was statistically significant. These results were confirmed by quantitative immunohistochemistry. Compared to control, PECAM-1 was by approximatively threefold increased in all groups of patients. This is the first study to demonstrate the occurrence of microthrombi in the failing human heart. The occurrence of microthrombi is associated with increased expression of VWF and the number of WPb, being more pronounced in ICM. These changes are likely not compensated by increases in PECAM-1 expression.

Protective effect of FAK inhibitor PF-562271 against human umbilical vein endothelial cell injury induced by aging platelets

To investigate the protective effect of PF-562271, a FAK inhibitor, against aging platelet-induced injury in human umbilical vein endothelial cells (HUVECs). Cultured HUVECs were treated with vehicle, lipopolysaccharide (LPS), LPS+aging platelets, or LPS+aging platelets+PF-562271. The changes in protein expressions of FAK, pFAK and PECAM-1 in the treated cells were detected using Western blotting and immunofluorescence assay, and the level of reactive oxygen species (ROS) was detected with flow cytometry. The changes of barrier function of the cells were assessed with cell permeability test and transendothelial cell resistance test. RT-qPCR was used to analyze mRNA expressions of inflammatory factors, and pro-inflammatory cytokine levels in the culture supernatants was determined with enzyme-linked immunosorbent assay. Immunofluorescence assay was used to examine the effect of the ROS inhibitor vitamin C on PECAM-1 expression in the cells with different treatments. Treatment of HUVECs with LPS and aging platelets significantly increased cellular protein expressions of FAK, pFAK and PECAM-1, which were effectively lowered by addition of PF-562271 (P < 0.05). LPS and aged platelets obviously enhanced ROS production in the cells, which was inhibited by the addition of PF-562271 (P < 0.001). PF-562271 significantly alleviated the damage of endothelial cell barrier function of the cells caused by LPS and aging platelets (P < 0.01). The expressions of TNF-α, IL-6 and IL-8 in HUVECs increased significantly after exposure to LPS and aging platelets, and were obviously lowered after treatment with PF-562271 (P < 0.05). Treatment with vitamin C significantly decreased the expression of PECAM-1 protein in the cells (P < 0.01). The FAK inhibitor PF-562271 alleviates endothelial cell damage induced by LPS and aging platelets by lowering cellular oxidative stress levels and reducing inflammatory responses.

BIOFUNCTIONALIZED 3D-BIOPRINTED VASCULAR-LIKE STRUCTURES: AN ADVANCED APPROACH TO PROMOTE ENDOTHELIAL TISSUE REGENERATION

Biofabrication is a popular technique to produce personalized constructs for tissue engineering. In this study we combined laponite (Lap), gellan gum (GG) with platelet-rich plasma (PRP) aiming to enhance the endothelial regeneration through the synergistic effects of their individual properties. Laponite has the ability to form porous three-dimensional networks mimicking the extracellular matrix structure, and PRP delivery of growth factors stimulates the endothelial cell proliferation and migration, offering a composite bioink for cell growth and support. The sustained release of these growth factors from the GG-laponite-PRP composite material over time provides a continuous source of stimulation for the cells, leading to more effective tissue engineering strategies for endothelial tissue regeneration. Four blend compositions comprising 1% w/v GG and 0.5 or 1% w/v Lap and 25% v/v PRP were combined with Wharton jelly mesenchymal stem cells (WJ-MSCs) and bioprinted into vessel-like structures with an inner diameter of 3 mm and a wall thickness of 1 mm. Stress/strain analysis revealed the elastomeric properties of the hydrogels with Young modulus values of 10 MPa. Increasing the Lap concentration led to a non-significant decrease of swelling ratio from 93 to 91%. Live/dead assay revealed cell viability of at least 76%, with the 0.5%Lap-GG viability exceeding 99% on day 21. Gradual increase of glycosaminoglycans accumulation and collagen production indicate promotion of ECM formation. The expression and membranous localization of PECAM-1 from day 7 and the granular intracellular localization of vWF after 2 weeks demonstrate in vitro endothelial functionality. In vivo subcutaneous implantation indicated the absence of any adverse immunological reactions. The results reveal the expression of both vWF and PECAM-1 by WJ-MSCs entrapped in all four construct compositions with significantly higher expression of vWF in the presence of PRP.

Polymer-Based Electrospun Vascular Grafts: A Study of Constructs and Endothelial Interactions

This study investigates tissue-engineered vascular grafts using electrospun polycaprolactone (PCL) and poly(l-lactide-co-caprolactone) (PLCL) polymers. The goal is to assess human umbilical endothelial cell (HUVEC) adhesion and proliferation on the fabricated grafts. Electrospinning produces nanofibrous scaffolds mimicking the ECM, fostering a suitable environment for cellular growth. Tubular surfaces from PCL and PLCL with randomly distributed fibers are cultured with HUVECs. The scaffolds underwent MTS analysis to assess cell viability, along with PECAM1 and PCDH12 gene expression analysis to observe cell-scaffold interactions. In the MTS analysis, on the 14th day, the PCL samples exhibit a 20% higher proliferation value than the control group, while the PLCL samples show an 8% increase. However, upon examining gene expression analyses, it is evident that the PLCL samples demonstrated a higher fold-change in both PECAM1 and PCDH12 gene expressions on days 3, 7, and 14 compared to the PCL samples. The outcomes demonstrate the potential of the developed electrospun vascular grafts for cardiovascular tissue engineering.

Coculture model of a liver sinusoidal endothelial cell barrier and HepG2/C3a spheroids-on-chip in an advanced fluidic platform

The liver is one of the main organs involved in the metabolism of xenobiotics and a key organ in toxicity studies. Prior to accessing the hepatocytes, xenobiotics pass through the hepatic sinusoid formed by liver sinusoidal endothelial cells (LSECs). The LSECs barrier regulates the kinetics and concentrations of the xenobiotics before their metabolic processing by the hepatocytes. To mimic this physiological situation, we developed an invitro model reproducing an LSECs barrier in coculture with a hepatocyte biochip, using a fluidic platform. This technology made dynamic coculture and tissue crosstalk possible. SK-HEP-1 and HepG2/C3a cells were used as LSECs and as hepatocyte models, respectively. We confirmed the LSECs phenotype by measuring PECAM-1 and stabilin-2 expression levels and the barrier's permeability/transport properties with various molecules. The tightness of the SK-HEP-1 barrier was enhanced in the dynamic coculture. The morphology, albumin secretion, and gene expression levels of markers of HepG2/C3a were not modified by coculture with the LSECs barrier. Using acetaminophen, a well-known hepatotoxic drug, to study tissue crosstalk, there was a reduction in the expression levels of the LSECs markers stabilin-2 and PECAM-1, and a modification of those of CLEC4M and KDR. No HepG2/C3a toxicity was observed. The metabolisation of acetaminophen by HepG2/C3a monocultures and cocultures was confirmed. Although primary cells are required to propose a fully relevant model, the present approach highlights the potential of our system for investigating xenobiotic metabolism and toxicity.

Scalable and stable human pluripotent stem cell-derived microvascular-like endothelial cells for cardiac regeneration and disease modelling applications

Abstract Introduction The microvasculature is a vital constituent of the adult human vasculature 1. Cardiac tissue engineering, in vitro models of cardiac remodelling and regeneration, and disease models of the microvasculature would benefit from the inclusion of well-characterised, phenotypically stable microvascular-like endothelial cells (ECs) that could be generated at scale without xenogeneic reagents. Primary microvascular ECs have been utilised for such applications however, they are susceptible to passaging-induced senescence². Moreover, alternative solutions including current protocols for the derivation of human pluripotent stem cell-derived ECs (hPSC-ECs) generate cells with a heterogenous vascular identity that often transdifferentiate into non-EC lineages³. Purpose The purpose of this study was to create a 3D, xenogeneic-free differentiation protocol that yielded stable hPSC-derived microvascular-like ECs (hPSC-MVECs) at scale. Methods Endothelial differentiation of hPSCs was conducted in 2D adherent monolayers and within stirred 3D bioreactors for 12 days. Thereafter, CD31pos ECs were isolated via fluorescence-activated cell sorting (FACS) and cultured for a further 14 days. Gene expression analysis of hPSCs undergoing 2D and 3D differentiation was evaluated via RT-qPCR. The day 26 hPSC-ECs were treated with VEGFA (0 – 50 ng/ml) for a further 7 days and evaluated for CD31 expression via high-content image analysis. The angiogenic profiles of 2D-, 3D-, and 3D-hPSC-ECs cultured in high concentration VEGFA (herein, 3D+V), relative to primary Human Cardiac Microvascular Endothelial Cells (HMVEC-Cs) was assessed using the Proteome Profiler Human Angiogenesis Array. Transcriptomic analysis of these EC populations was subsequently conducted via single-cell RNA sequencing (scRNA-seq). Results Complex vascular clusters emerged by day 12 of the 3D differentiation protocol (fig. 1). The emergent 3D hPSC-ECs had a comparable expression of PECAM1 and CDH5 relative to 2D-derived hPSC-ECs however, VEGFA expression was significantly reduced (P&amp;lt;0.01, fig. 2A). VEGFA treatment at 50 ng/ml yielded phenotypically stable hPSC-ECs (3D+V, fig. 2B). Principal component analysis of the angiogenic factors assayed for revealed 3D+V hPSC-ECs clustered with HMVEC-Cs (fig. 2C). scRNA-seq identified a subset of 3D-derived hPSC-ECs expressing genes associated with microvascular vessels (GMFG, PLVAP), capillary ECs (RGCC, GLUL), and angiogenic tip cells (ESM1, HSPG2). Conclusion The scalable and xenogeneic-free 3D protocol outlined within allows for the attainment of hPSC-derived microvascular-like ECs with high angiogenic potential. The absence of Matrigel enhances the translational capacity of the hPSC-MVECs arising from this protocol that could now be derived from patient-specific hPSC lines for evaluation in pre-clinical models of post-myocardial infarction cardiac regeneration or for in vivo models of cardiac remodelling and microvasculature disease.

Abstract 15041: Single-Cell RNA Sequencing Reveals Four Distinctive Endothelial Subpopulations Through Mouse Endothelial Aging

Introduction: Endothelial cell (EC) dysfunction is a hallmark of vascular aging, contributing to age-related vascular diseases. Elucidating EC aging at the single cell level has significant scientific and therapeutic potential. Research Question: What is the landscape of EC aging at the single cell level? Methods: Mouse aortas were harvested from 1-, 10-, and 20 month-old mice (n=2 males and 2 females at each time point). Pooled single-cell suspensions were prepared, and PECAM1+ cells were enriched by magnetic-activated cell sorting. Results: Single cell RNA sequencing revealed 879 ECs, categorized into six subpopulations (EC 1-6). Of the three canonical EC markers ( Pecam1 , Cdh5, and Kdr ) EC1 and 2 showed higher expression of Pecam1 , whereas EC3 and 4 showed higher expression of Cdh5 and Kdr . ECs from young (1 month-old), middle-aged (10 month-old), and elderly mice (20 month-old) were enriched in EC1, EC3, and EC4, respectively. Gene regulatory network analysis identified specific regulons for each EC subcluster. EC1 displayed progenitor-like features ( Isl1 as one of the top regulons, Procr and Cd34 as highly expressed genes) with high angiogenic potential ( Twist1 as one of the top regulons, Timp2 , Mmp14 , and Mmp2 as highly expressed genes) and the longest G1 phase suggesting its quiescence. EC3 cells exhibited high proliferative status demonstrated by G2M or S phase, accompanied by upregulation of stress-responsive TF Atf3 and NF-κB family members. EC4 demonstrated pronounced Pparg regulon activity. Genes directly regulated by Pparg ( Scarb1 and Cd36 ), and genes involved in fatty acid metabolism and atherogenesis ( Tcf15 , Fabp4 , Gpihbp1 , Lpl , and Meox2) were highly expressed in EC4 and EC3. Conclusions: Our analysis identified four distinct EC subpopulations through the aging process of mouse aortic ECs: EC1, Pecam1 h progenitor-like EC; EC2, Pecam1 h common EC; EC3, Cdh5 h Kdr h inflammatory atherogenic EC; and EC4, Cdh5 h Kdr h non-inflammatory atherogenic EC.

Nicaraven partially attenuates radiation-induced expression of adhesion molecules in the murine lung

Thoracic irradiation has been found to promote cancer metastasis in the lungs, but the relevant mechanism remains unclear. Adhesion and extracellular matrix (ECM) molecules, major components of the tissue microenvironment, play a critical role in cancer metastasis. We have found that nicaraven, a small chemical compound, effectively protects normal tissue (stem) cells against radiation-induced injuries and attenuates cancer metastasis. In this study, we tried to investigate whether nicaraven regulates adhesion and ECM molecules expressions in the irradiated lungs. To find the potential adhesion and ECM molecules are regulated by nicaraven in the irradiated lungs, we collected the lungs from mice 24 h after thorax irradiation with a single dose of 5 Gy X-rays, and then widely evaluated the expression of adhesion and ECM molecules by RT-PCR assay. Our data showed that several adhesion and ECM molecules were up- or down-regulated in the irradiated murine lungs. Interestingly, nicaraven effectively attenuated radiation-enhanced expressions of Itga2 and Pecam1 in the murine lungs. Our study demonstrated that nicaraven suppresses the adhesion and ECM remodeling in the irradiated lungs, which may contribute to attenuate the radiation-induced enhancement of lung metastasis. Further study is warranted to determine how nicaraven regulates the expression of adhesion and ECM molecules and prevents cancer metastasis after irradiation.

TLR7/TLR8 activation and susceptibility genes synergize to breach gut barrier in a mouse model of lupus.

Mounting evidence suggests that increased gut permeability, or leaky gut, and the resulting translocation of pathobionts or their metabolites contributes to the pathogenesis of Systemic Lupus Erythematosus. However, the mechanisms underlying the induction of gut leakage remain unclear. In this study, we examined the effect of a treatment with a TLR7/8 agonist in the B6.Sle1.Sle2.Sle3 triple congenic (TC) mouse, a spontaneous mouse model of lupus without gut leakage. Lupus-prone mice (TC), TC.Rag1-/- mice that lack B and T cells, and congenic B6 healthy controls were treated with R848. Gut barrier integrity was assessed by measuring FITC-dextran in the serum following oral gavage. Claudin-1 and PECAM1 expression as well as the extent of CD45+ immune cells, B220+ B cells, CD3+ T cells and CD11b+ myeloid cells were measured in the ileum by immunofluorescence. NKp46+ cells were measured in the ileum and colon by immunofluorescence. Immune cells in the ileum were also analyzed by flow cytometry. R848 decreased gut barrier integrity in TC but not in congenic control B6 mice. Immunofluorescence staining of the ileum showed a reduced expression of the tight junction protein Claudin-1, endothelial cell tight junction PECAM1, as well as an increased infiltration of immune cells, including B cells and CD11b+ cells, in R848-treated TC as compared to untreated control mice. However, NKp46+ cells which play critical role in maintaining gut barrier integrity, had a lower frequency in treated TC mice. Flow cytometry showed an increased frequency of plasma cells, dendritic cells and macrophages along with a decreased frequency of NK cells in R848 treated TC mice lamina propria. In addition, we showed that the R848 treatment did not induce gut leakage in TC.Rag1-/- mice that lack mature T and B cells. These results demonstrate that TLR7/8 activation induces a leaky gut in lupus-prone mice, which is mediated by adaptive immune responses. TLR7/8 activation is however not sufficient to breach gut barrier integrity in non-autoimmune mice.

Molecular Mechanisms Behind Vascular Mimicry as the Target for Improved Breast Cancer Management.

Breast cancer has a high incidence and mortality rate in women due to metastasis and drug resistance which is associated with vasculogenic mimicry (VM). We purposed to explore VM formulation in breast cancer and mechanism of which is involved in EphA2/PIK3R1/CTNNB1 in the present study. The expression of EphA2/PIK3R1/CTNNB1 and breast cancer patient prognosis was analyzed from TCGA data, both gene and protein expression as well as VM were measured in human breast cancer tissue samples collected in our study. The relationship between EphA2/PIK3R1/CTNNB1 and the formation of VM in breast cancer and its possible regulatory mechanism was explored. The results of the bioinformatics analysis based on TCGA showed that the expression of PIK3R1/ CTNNB1/ PECAM1 (CD31) in tumor tissues was significantly lower than that in normal tissues. EphA2 was positively correlated with PIK3R1, PIK3R1 with CTNNB1, and CTNNB1 with PECAM1 expression in breast cancer tissues. The results of detection in breast cancer and adjacent tissues indicated that the expression of EphA2/PIK3R1/CTNNB1 in cancer tissues was significantly lower than that in adjacent tissues. The expression of PIK3R1 was positively correlated with EphA2 and CTNNB1 expression, respectively, as well as EphA2 expression correlated with CTNNB1 expression positively. VM formation was significantly increased in breast cancer tissues compared with adjacent tissues. Our results suggested that the formation of VM in breast cancer may be related to the EphA2/PIK3R1/CTNNB1 molecular signaling pathway.

E2F2 modulates cell adhesion through the transcriptional regulation of PECAM1 in multiple myeloma.

Multiple myeloma (MM) is the second most common haematological malignancy. Despite the development of new drugs and treatments in recent years, the therapeutic outcomes of patients are not satisfactory. It is necessary to further investigate the molecular mechanism underlying MM progression. Herein, we found that high E2F2 expression was correlated with poor overall survival and advanced clinical stages in MM patients. Gain- and loss-of-function studies showed that E2F2 inhibited cell adhesion and consequently activated cell epithelial-to-mesenchymal transition (EMT) and migration. Further experiments revealed that E2F2 interacted with the PECAM1 promoter to suppress its transcriptional activity. The E2F2-knockdown-mediated promotion of cell adhesion was significantly reversed by the repression of PECAM1 expression. Finally, we observed that silencing E2F2 significantly inhibited viability and tumour progression in MM cell models and xenograft mouse models respectively. This study demonstrates that E2F2 plays a vital role as a tumour accelerator by inhibiting PECAM1-dependent cell adhesion and accelerating MM cell proliferation. Therefore, E2F2 may serve as a potential independent prognostic marker and therapeutic target for MM.

(097) A Novel Therapeutic Strategy for Recovery from Cavernous Veno-Occlusive Dysfunction through Chronic Administration of Hepatocyte Growth Factor and a JNK Inhibitor in a Rat Model of Cavernous Nerve Injury

Abstract Introduction Structural alterations of penis including cavernosal apoptosis and fibrosis induce venous leakage in the corpus cavernosum or cavernosal veno-occlusive dysfunction, a key pathophysiology of erectile dysfunction (ED) after radical prostatectomy. Objective We aimed to determine if JNK inhibition in combination with intracavernosal administration of hepatocyte growth factor (HGF) would completely restore cavernosal veno-occlusive function (CVOF) in a rat model of ED induced by bilateral CN crush injury (CNCI). Methods A total of forty-two male Sprague-Dawley rats were randomly assigned to sham control (S), CNCI (I) and CNCI treated with combination of JNK inhibitors and HGF (J+H) for 5 weeks after surgery. All rats in each group were evaluated by dynamic infusion cavernosometry (DIC), caspase-3 activity assay, Masson’s trichrome staining, immunohistochemical staining of α-smooth muscle actin (α-SMA) and immunoblotting at 5 weeks after surgery. Results Regarding CVOF, Group I showed a decreased papaverine response, an increased maintenance and drop rates compared to Group S. Group J+H showed significant improvements in the three DIC parameters compared to Group I. There were no differences in papaverine response and drop rate between Group J+H and Group S. Regarding the structural integrity of corpus cavernosum, Group I had an increased caspase-3 activity, decreased SM/collagen ratio, decreased content of SM, decreased protein expression of PECAM-1, and decreased phosphorylation of c-Jun and c-Met. Group J+H had significant alleviation in the histological and molecular derangement compared to Group I. There were no differences in caspase-3 activity, SM content, PECAM-1 protein expression, c-Jun phosphorylation and c-Met phosphorylation between Group J+H and Group S. Conclusions Our data indicate that chronic administration of JNK inhibitors and HGF may restore CVOF to the level comparable to sham control level through preservation of structural integrity of the corpus cavernosum. Combination of JNK inhibition and HGF might be a potential therapeutic option for recovering from CVOD. Disclosure No

A Systematic Study of Traditional Chinese Medicine for the Treatment of Lung Adenocarcinoma Using a Reverse Network of Key Targets Based on Bioinformatics and Molecular Docking: Curcumin and Trans-Resveratrol as Potential Drug Candidates for Lung Adenocarcinoma

Background Lung adenocarcinoma (LUAD) is a dominant tumor with high morbidity and mortality. In spite of innovations in surgery, chemotherapy, and targeted therapies, the prognosis for patients with LUAD remains unsatisfactory. Therefore, it is particularly important to study the biological markers of the occurrence, development, and prognosis of this disease. Methods In this study, 3 datasets were selected from the Gene Expression Omnibus (GEO) database to screen differentially expressed genes (DEGs). Then, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed using Database Annotation, Visualization and Integrated Discovery (DAVID). In addition, a protein-protein interaction network was performed and 10 key genes were analyzed. Gene and protein expression were analyzed using The Cancer Genome Atlas (TCGA) and The Human Protein Atlas (HPA) databases, respectively. Then, overall survival (OS) rate was analyzed using Kaplan-Meier plotter database. The chemical components were downloaded from the HERB database. Finally, the chemical constituents were docked with 10 targets by molecular docking. By using in vitro studies, we evaluated the effects of curcumin and trans-resveratrol on the proliferation of LUAD cells. Results A total of 122 upregulated and 434 downregulated genes were identified. Then, 10 key genes (glyceraldehyde-3-phosphate dehydrogenase (GAPDH), interleukin-1 beta (IL1B), von Willebrand factor (VWF), matrix metalloproteinase-9 (MMP9), CD44 antigen (CD44), transcription factor Jun (JUN), platelet endothelial cell adhesion molecule (PECAM1), hematopoietic progenitor cell antigen CD34 (CD34), peroxisome proliferator-activated receptor gamma (PPARG), and collagen alpha-1(I) chain (COL1A1)) were obtained. TCGA results showed that GAPDH, MMP9, and COL1A1 were upregulated, while IL-1B, VWF, CD44, JUN, PECAM1, CD34, and PPARG were downregulated in cancer tissues. Kaplan-Meier plotter analysis also showed that high expression of GAPDH, PPARG, and COL1A1, and low expression of VWF, PECAM1, CD34, PPARG, and COL1A1 were associated with poor prognosis in LUAD. Combined with gene expression, staging, immunohistochemistry, and OS prognostic analysis, the results showed that COL1A1 was a potential target for the occurrence and prognosis of LUAD. In addition, 2 key components (curcumin and trans-resveratrol) had good docking effect with COL1A1. We found that curcumin and trans-resveratrol significantly inhibited the proliferation of LUAD cells and significantly decreased the expression of COL1A1 and MMP9. Conclusion In conclusion, our study identified the potential target of LUAD and the main traditional Chinese medicine components (curcumin and trans-resveratrol) for LUAD treatment. This study provides potential therapeutic targets and treatment strategies for the treatment of LUAD.

Angiogenic genes and proteins are differentially expressed in left and right ventricular tissue in perinatal sheep hearts

Birth places a great stress on the fetal heart due to increased cardiac workload, following a disconnection from the low-resistance placenta and closure of fetal shunts. The mechanisms that regulate myocardial microvascular growth and development during the perinatal period are largely unknown. We hypothesized that birth stimulates an increase in angiogenic gene and protein expression in a ventricular dependent manner to reflect the changing roles for the left and right ventricles (LV, RV). Fetal (135 d gestation, dGA; term=147 dGA) and neonatal (1 and 5 postnatal days, PD) sheep LV and RV were snap frozen. Gene expression of key angiogenic regulators ( VEGFA, VEGFR1, VEGFR2, ANGPT1, ANGPT2, PGC1A), endothelial cell growth ( DDL4, NOTCH4, SPP1, PECAM1, NCL), nitric oxide synthesis ( NOS2, NOS3), and extracellular matrix (ECM) remodeling ( MMP2, MMP9, THBS1) were quantified using real-time qPCR (n=12/age group). Protein expression of VEGFA and VEGF-R2 were measured by Western blot (n=5/age group). Data were analyzed by two-way ANOVA with Tukey’s post-hoc test to determine effects of age, ventricle, and interaction. Significance was set at P&lt;0.05. At 135 dGA, all angiogenic, nitric oxide synthesis, ECM, DDL4, SPP1, and PECAM1 mRNA expression levels were higher in the RV vs. LV. At PD1, there were no differences between LV and RV. At PD5, VEGFA, VEGFR1, ANGPT1, ANGPT2, PGC1A, DDL4, SPP1, PECAM1, NCL, MMP2, and THBS1 mRNA expression levels were again higher in the RV vs. LV. At 135 dGA, VEGFA and VEGF-R2 protein expression levels were 76% and 72% lower, respectively, in the RV vs. LV. Within each ventricle, age related changes to mRNA expression patterns were unique. In the LV, mRNA expression of NOTCH4 and NCL increased stepwise from 135 dGA to PD5; however, in the RV, both were upregulated at PD1 but returned to fetal levels by PD5. In contrast, all angiogenic, ECM, DDL4, SPP1, PECAM1, and NOS2 genes were downregulated in the RV at PD1 but all returned to fetal levels by PD5. In the LV, VEGF-R2 protein expression was 56% and 73% lower at PD 1 and 5, respectively, vs. 135 dGA. In summary, gene and protein expression patterns involved in angiogenesis and vascular remodeling change over the perinatal period and are differentially expressed in the ventricles. Greater angiogenic gene expression levels in the RV vs. the LV at 135 dGA might be due to the RV serving as the main systemic pump in utero, thus requiring relatively increased microcirculation. However, reduced VEGFA and VEGF-R2 protein levels at 135 dGA contradict this hypothesis; histological studies to determine vascularity are ongoing. Likewise, the subsequent downregulation of angiogenic genes in the RV at PD1 might be due to the RV’s sudden decrease in cardiac output as the LV becomes the main pump. The underlying reasons for why LV angiogenic genes are not significantly upregulated in the early postnatal period, given its new role as the main systemic pump, are yet to be elucidated. NIH R21-HL152112 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.