Ion channel Piezo1 activation aggravates the endothelial dysfunction under a high glucose environment.

BACKGROUND: Vasculopathy is the most common complication of diabetes. Endothelial cells located in the innermost layer of blood vessels are constantly affected by blood flow or vascular components; thus, their mechanosensitivity plays an important role in mediating vascular regulation. Endothelial damage, one of the main causes of hyperglycemic vascular complications, has been extensively studied. However, the role of mechanosensitive signaling in hyperglycemic endothelial damage remains unclear. METHODS: Vascular endothelial-specific Piezo1 knockout mice were generated to investigate the effects of Piezo1 on Streptozotocin-induced hyperglycemia and vascular endothelial injury. In vitro activation or knockdown of Piezo1 was performed to evaluate the effects on the proliferation, migration, and tubular function of human umbilical vein endothelial cells in high glucose. Reactive oxygen species production, mitochondrial membrane potential alternations, and oxidative stress-related products were used to assess the extent of oxidative stress damage caused by Piezo1 activation. RESULTS: Our study found that in VECreERT2;Piezo1flox/flox mice with Piezo1 conditional knockout in vascular endothelial cells, Piezo1 deficiency alleviated streptozotocin-induced hyperglycemia with reduced apoptosis and abscission of thoracic aortic endothelial cells, and decreased the inflammatory response of aortic tissue caused by high glucose. Moreover, the knockout of Piezo1 showed a thinner thoracic aortic wall, reduced tunica media damage, and increased endothelial nitric oxide synthase expression in transgenic mice, indicating the relief of endothelial damage caused by hyperglycemia. We also showed that Piezo1 activation aggravated oxidative stress injury and resulted in severe dysfunction through the Ca2+-induced CaMKII-Nrf2 axis in human umbilical vein endothelial cells. In Piezo1 conditional knockout mice, Piezo1 deficiency partially restored superoxide dismutase activity and reduced malondialdehyde content in the thoracic aorta. Mechanistically, Piezo1 deficiency decreased CaMKII phosphorylation and restored the expression of Nrf2 and its downstream molecules HO-1 and NQO1. CONCLUSION: In summary, our study revealed that Piezo1 is involved in high glucose-induced oxidative stress injury and aggravated endothelial dysfunction, which have great significance for alleviating endothelial damage caused by hyperglycemia.

USP18 Curbs the Progression of Metabolic Hypertension by Suppressing JAK/STAT Pathway.

Hypertension is a pathological state of the metabolic syndrome that increases the risk of cardiovascular disease. Managing hypertension is challenging, and we aimed to identify the pathogenic factors and discern therapeutic targets for metabolic hypertension (MHR). An MHR rat model was established with the combined treatment of a high-sugar, high-fat diet and ethanol. Histopathological observations were performed using hematoxylin-eosin and Sirius Red staining. Transcriptome sequencing was performed to screen differentially expressed genes. The role of ubiquitin-specific protease 18 (USP18) in the proliferation, apoptosis, and oxidative stress of HUVECs was explored using Cell Counting Kit-8, flow cytometry, and enzyme-linked immunosorbent assays. Moreover, USP18 downstream signaling pathways in MHR were screened, and the effects of USP18 on these signaling pathways were investigated by western blotting. In the MHR model, total cholesterol and low-density lipoprotein levels increased, while high-density lipoprotein levels decreased. Moreover, high vessel thickness and percentage of collagen were noted along with increased malondialdehyde, decreased superoxide dismutase and catalase levels. The staining results showed that the MHR model exhibited an irregular aortic intima and disordered smooth muscle cells. There were 78 differentially expressed genes in the MHR model, and seven hub genes, including USP18, were identified. USP18 overexpression facilitated proliferation and reduced apoptosis and oxidative stress in HUVECs treated with Ang in vitro. In addition, the JAK/STAT pathway was identified as a USP18 downstream signaling pathway, and USP18 overexpression inhibited the expression of JAK/STAT pathway-related proteins. Conclusively, USP18 restrained MHR progression by promoting cell proliferation, reversing apoptosis and oxidative stress, and suppressing the JAK/STAT pathway.

Procyanidin B2 alleviates oxidized low-density lipoprotein-induced cell injury, inflammation, monocyte chemotaxis, and oxidative stress by inhibiting the nuclear factor kappa-B pathway in human umbilical vein endothelial cells.

BACKGROUND: Oxidized low-density lipoprotein (ox-LDL) can initiate and affect almost all atherosclerotic events including endothelial dysfunction. In this text, the role and underlying molecular basis of procyanidin B2 (PCB2) with potential anti-oxidant and anti-inflammatory activities in ox-LDL-induced HUVEC injury were examined. METHODS: HUVECs were treated with ox-LDL in the presence or absence of PCB2. Cell viability and apoptotic rate were examined by CCK-8 assay and flow cytometry, respectively. The mRNA and protein levels of genes were tested by RT-qPCR and western blot assays, respectively. Potential downstream targets and pathways of apple procyanidin oligomers were examined by bioinformatics analysis for the GSE9647 dataset. The effect of PCB2 on THP-1 cell migration was examined by recruitment assay. The effect of PCB2 on oxidative stress was assessed by reactive oxygen species (ROS) level, malondialdehyde (MDA) content, and mitochondrial membrane potential (MMP). RESULTS: ox-LDL reduced cell viability, induced cell apoptosis, and facilitated the expression of oxidized low-density lipoprotein receptor 1 (LOX-1), C-C motif chemokine ligand 2 (MCP-1), vascular cell adhesion protein 1 (VCAM-1) in HUVECs. PCB2 alleviated ox-LDL-induced cell injury in HUVECs. Apple procyanidin oligomers triggered the differential expression of 592 genes in HUVECs (|log2fold-change| > 0.58 and adjusted p-value < 0.05). These dysregulated genes might be implicated in apoptosis, endothelial cell proliferation, inflammation, and monocyte chemotaxis. PCB2 inhibited C-X-C motif chemokine ligand 1/8 (CXCL1/8) expression and THP-1 cell recruitment in ox-LDL-stimulated HUVECs. PCB2 inhibited ox-LDL-induced oxidative stress and nuclear factor kappa-B (NF-κB) activation in HUVECs. CONCLUSION: PCB2 weakened ox-LDL-induced cell injury, inflammation, monocyte recruitment, and oxidative stress by inhibiting the NF-κB pathway in HUVECs.

Oral cancer cell to endothelial cell communication via exosomal miR-21/RMND5A pathway.

Required for meiotic nuclear division 5 homolog A (RMND5A), a novel ubiquitin E3 Ligase, has been reported to correlate with poor prognosis of several cancers. However, its role in endothelial cells has not been reported. In this study, overexpression of RMND5A in human umbilical vein endothelial cells (HUVECs) was performed via lentiviral infection, followed by MTT, would healing and tube formation assay as well as signaling analysis. Moreover, crosstalk between HUVECs and oral squamous cell carcinoma (OSCC) cells was investigated by indirect co-culture with condition medium or tumor cell derived exosomes. Our results showed that overexpression of RMND5A reduced the proliferation, migration and tube formation ability of HUVECs by inhibiting the activation of ERK and NF-κB pathway. Interestingly, OSCC cells can inhibit RMND5A expression of endothelial cells via exosomal miR-21. In summary, our present study unveils that OSCC cells can activate endothelial cells via exosomal miR-21/RMND5A pathway to promote angiogenesis, which may provide novel therapeutic targets for the treatment of OSCC.

Tumor-derived exosomal miR-1247-3p promotes angiogenesis in bladder cancer by targeting FOXO1.

Tumor-derived exosomes are highly correlated with tumor progression and angiogenesis. This study was designed to probe the role of tumor-derived exosomal miR-1247-3p in mediating the angiogenesis in bladder cancer. Exosomes isolation from the culture medium of normal or bladder cancer cell lines was performed using a differential centrifugation method. miR-1247-3p expression in exosomes and cells was detected by quantitative real-time PCR (qRT-PCR). The effect of exosomes on the angiogenesis of human umbilical vein endothelial cells (HUVECs) was assessed using cell counting kit-8 (CCK-8), transwell and tube formation assays. The interaction between miR-1247-3p and forkhead box protein O1 (FOXO1) was studied using luciferase reporter and RNA pull down assays. Exosomes were successfully isolated from T24, UM-UC-3, and SV-HUC-1 cells, as confirmed by corresponding identifications. Functional experiments revealed that exosomes derived from T24 and UM-UC-3 cells significantly enhanced the abilities of proliferation, migration, angiogenesis, and vascular endothelial-derived growth factor (VEGF) secretion in HUVECs. miR-1247-3p was highly expressed in exosomes derived from T24 and UM-UC-3 cells, and exosomes derived from miR-1247-3p inhibitor-transfected cells reduced HUVEC viability, migration, tube formation, and VEGF level. FOXO1 was confirmed as a direct target of miR-1247-3p. Rescue assays suggested that the effect of miR-1247-3p inhibition on the viability, migration, and angiogenesis of HUVECs was partly abrogated by the knockdown of FOXO1. Our data suggest that miR-1247-3p is up-regulated in tumor-derived exosomes, thereby inhibiting FOXO1 expression and facilitating angiogenesis in bladder cancer.

ERp29 Attenuates Nicotine-Induced Endoplasmic Reticulum Stress and Inhibits Choroidal Neovascularization.

Nicotine-induced endoplasmic reticulum (ER) stress in retinal pigment epithelium (RPE) cells is thought to be one pathological mechanism underlying age-related macular degeneration (AMD). ERp29 attenuates tobacco extract-induced ER stress and mitigates tight junction damage in RPE cells. Herein, we aimed to further investigate the role of ERp29 in nicotine-induced ER stress and choroidal neovascularization (CNV). We found that the expression of ERp29 and GRP78 in ARPE-19 cells was increased in response to nicotine exposure. Overexpression of ERp29 decreased the levels of GRP78 and the C/EBP homologous protein (CHOP). Knockdown of ERp29 increased the levels of GRP78 and CHOP while reducing the viability of ARPE-19 cells under nicotine exposure conditions. In the ARPE-19 cell/macrophage coculture system, overexpression of ERp29 decreased the levels of M2 markers and increased the levels of M1 markers. The viability, migration and tube formation of human umbilical vein endothelial cells (HUVECs) were inhibited by conditioned medium from the ERp29-overexpressing group. Moreover, overexpression of ERp29 inhibits the activity and growth of CNV in mice exposed to nicotine in vivo. Taken together, our results revealed that ERp29 attenuated nicotine-induced ER stress, regulated macrophage polarization and inhibited CNV.

TNF-α stimulated exosome derived from fibroblast-like synoviocytes isolated from rheumatoid arthritis patients promotes HUVEC migration, invasion and angiogenesis by targeting the miR-200a-3p/KLF6/VEGFA axis.

The pathogenesis of rheumatoid arthritis (RA) is heavily impacted by the inflammation and activation of fibroblast-like synoviocytes (FLS). The objective of this investigation is to clarify the involvement of exosomes derived from FLS stimulated by tumour necrosis factor α (TNF-α) in angiogenesis and the underlying mechanisms. FLS cells were obtained from synovial fluid of RA patients and exosomes were obtained from FLS cell supernatant with TNF-α stimulation by ultracentrifugation. Exosomes were subsequently analysed using transmission electron microscopy, nanoparticle tracking analysis, and western blotting. The functional effects of exosomes with TNF-α stimulation on human umbilical vein endothelial cells (HUVEC) migration, invasion, and angiogenesis was evaluated using wound scratch healing test, transwell invasion assay, and tube formation assay. DNA nanoball-seq (DNBSEQ) sequencing platform was utilised to analysis different expression miRNA from exosomes, miRNA and mRNA from HUVEC. The expression level of miR-200a-3p was determined through quantitative real-time polymerase chain reaction (qRT-PCR). The quantification of KLF6 and VEGFA expression levels were performed by qRT-PCR and western blot analysis. The validation of the association between miR-200a-3p and KLF6 was established through a fluorescence enzyme reporting assay. In comparison to exosome induced by PBS, exosome induced by TNF-α exhibited a substantial exacerbation of invasion, migration, and angiogenesis in HUVEC. 4 miRNAs in exosomes and HUVEC cells, namely miR-1246, miR-200a-3p, miR-30a-3p, and miR-99b-3p was obtained. MiR-200a-3p maintained high consistency with the sequencing results. We obtained 5 gene symbols, and KLF6 was chose for further investigation. The expression of miR-200a-3p in exosomes induced by TNF-α and in HUVEC treated with these exosomes demonstrated a significantly increase. Additionally, HUVEC cells displayed a notable decrease in KLF6 expression and a significant elevation in VEGFA expression. This was further confirmed by the fluorescence enzyme report assay, which provided evidence of the direct targeting of KLF6 by miR-200a-3p. Exosomes induced by TNF-α have the ability to enhance the migration, invasion, and angiogenesis of HUVEC cells via the miR-200a-3p/KLF6/VEGFA axis.

BMP4 inhibits corneal neovascularization by interfering with tip cells in angiogenesis.

Corneal neovascularization (CNV) can lead to impaired corneal transparency, resulting in vision loss or blindness. The primary pathological mechanism underlying CNV is an imbalance between pro-angiogenic and anti-angiogenic factors, with inflammation playing a crucial role. Notably, a vascular endothelial growth factor（VEGF）-A gradient triggers the selection of single endothelial cells（ECs） into primary tip cells that guide sprouting, while a dynamic balance between tip and stalk cells maintains a specific ratio to promote CNV. Despite the central importance of tip-stalk cell selection and shuffling, the underlying mechanisms remain poorly understood. In this study, we examined the effects of bone morphogenetic protein 4 (BMP4) on VEGF-A-induced lumen formation in human umbilical vein endothelial cells (HUVECs) and CD34-stained tip cell formation. In vivo, BMP4 inhibited CNV caused by corneal sutures. This process was achieved by BMP4 decreasing the protein expression of VEGF-A and VEGFR2 in corneal tissue after corneal suture injury. By observing the ultrastructure of the cornea, BMP4 inhibited the sprouting of tip cells and brought forward the appearance of intussusception. Meanwhile, BMP4 attenuated the inflammatory response by inhibiting neutrophil extracellular traps （NETs）formation through the NADPH oxidase-2（NOX-2）pathway. Our results indicate that BMP4 inhibits the formation of tip cells by reducing the generation of NETs, disrupting the dynamic balance of tip and stalk cells and thereby inhibiting CNV, suggesting that BMP4 may be a potential therapeutic target for CNV.

Different stimuli induce endothelial dysfunction and promote atherosclerosis through the Piezo1/YAP signaling axis.

Vascular endothelial dysfunction is the initial step in atherosclerosis (AS). AS tends to occur at vascular bifurcations and curves, and endothelial cells(ECs) are highly susceptible to injury due to mechanical forces induced by disturbed flow (DF) with inconsistent blood flow directions. However, the pathogenesis of endothelial cell dysfunction in AS remains unclear and needs further study. Here, we found that Piezo1 expression was significantly increased in DF- and oxidized low-density lipoprotein(ox-LDL)-treated HUVECs in vitro and a model of atherosclerotic plaque growth in ApoE-/- mice fed a Western diet. Furthermore, Piezo1 upregulated autophagy levels in the HUVECs model, which was reversed by Piezo1 knockdown with a lentivirus-mediated shRNA system. Mechanistically, the level of Yes-associated protein (YAP), a transcriptional coactivator in the Hippo pathway, was significantly elevated in the DF- and ox-LDL-induced HUVECs model, and this effect was further inhibited by Piezo1 knockdown. Moreover, the Piezo1 agonist Yoda1 inhibited the protein level of microtubule-associated protein 1 light chain 3-II(LC3-II) and increased the protein level of sequestosome1(p62/SQSTM1) in a dose-dependent manner, while significantly promoting the protein expression and nuclear translocation of YAP. The YAP inhibitor CA3 weakened Yoda1-mediated inhibition of autophagy. Our results suggest that Piezo1 may regulate endothelial autophagy by promoting YAP activation and nuclear translocation, thereby contributing to vascular endothelial dysfunction.

Extracellular shuttling miR-21 contributes to esophageal cancers and human umbilical vein endothelial cell communication in the tumor microenvironment and promotes tumor angiogenesis by targeting phosphatase and tensinhomolog.

BACKGROUND: Cell-cell communication by carcinoma-derived exosomes can influence the tumor microenvironment (TME) and regulate cancer progression. Based on the overexpression of microRNA-21-5p (miR-21) in plasma from patients diagnosed with esophageal squamous cell carcinoma (ESCC) and exosomes from ESCC cell lines identified earlier, this study aimed to explore the influence of exosomal miR-21 within the TME. METHOD: ScRNA-Seq and Bulk RNA-Seq were integrated to elucidate the communication between cancer and endothelial cells. The functionality and mechanisms by which exo-miR-21 derived from carcinoma regulate endothelial cell-mediated angiogenesis were assessed using a cocultivation model of EC9706 cells and recipient human umbilical vein endothelial cells (HUVECs), through blood vessel formation experiments, luciferase reporter assays, RT-qPCR, and western blot analysis. RESULT: A total of 3842 endothelial cells were extracted from the scRNA-seq data of ESCC samples and reclustered into five cell subtype. Cell-cell communication analysis revealed cancer cells presented a strong interaction with angiogenesis-like endothelial cells in secreted signaling. MiR-21 was unregulated in ESCC and the carcinoma-derived exo-miR-21 was significantly raised in HUVECs. The exo-miR-21 promoted the proliferation and migration of HUVECs while also enhancing, closed mesh count, and junction number in HUVECs. Mechanistically, dual-luciferase reporter assay revealed that PTEN was the target of miR-21. Meanwhile, p-Akt was significantly increased and suppressed by inhibition of miR-21 and PI3K inhibitor LY294002. CONCLUSION: Exo-miR-21-mediated communication between endothelial and cancer cells plays a pivotal role in promoting the angiogenesis of ESCC. Therefore, controlling exo-miR-21 could serve as a novel therapeutic strategy for ESCC by targeting angiogenesis.

CircDLGAP4 induces autophagy and improves endothelial cell dysfunction in atherosclerosis by targeting PTPN4 with miR-134-5p.

OBJECTIVE: Circular RNAs (circRNAs), a new subgroup of non-coding RNAs in the human transcriptome, are crucial in atherosclerosis (AS). Here, a newly identified circRNA circDLGAP4 was demonstrated to be downregulated in oxidized forms of low-density lipoprotein (ox-LDL)-induced HUVECs. METHODS: This research adopted ox-LDL to stimulate human umbilical vein endothelial cells (HUVECs) to mimic AS in vitro. To further validate the protective action of circDLGAP4 in AS, a mouse model of AS was constructed with a high-fat diet. Functional assays evaluated circDLGAP4 role in AS in vitro and in vivo. Moreover, mechanism assays evaluated association of circDLGAP4/miR-134-5p/PTPN4. RESULTS: CircDLGAP4 was induced to promote cell proliferative behavior and autophagy, inhibit apoptotic and inflammatory activities in ox-LDL-treated HUVECs, and attenuated endothelial barrier function. CircDLGAP4 regulated PTPN4 by directly targeting miR-134-5p. Meanwhile, inhibiting miR-134-5p reduced ox-LDL-induced cell dysfunction. Knockout of PTPN4 reversed circDLGAP4 overexpression or miR-134-5p downregulation in vitro. In addition, reducing circDLGAP4 or overexpressing miR-134-5p increased the red atherosclerotic plaque and lesion area of AS mice, reduced autophagy level, and promoted the release of inflammatory cytokines. CONCLUSION: This study extends the role of circRNA in AS by inducing autophagy and improving endothelial dysfunction in AS via the circDLGAP4/miR-134-5p/PTPN4 axis.

Hypoxia-induced tumor exosomes promote angiogenesis through miR-1825/TSC2/mTOR axis in oral squamous cell carcinoma.

BACKGROUND: Oral squamous cell carcinoma (OSCC) is characterized by enhanced angiogenesis resulting in poor prognosis despite improvements in diagnostic/therapeutic techniques. Here, we aimed at investigating potential roles of miR-1825 enclosed in OSCC-derived exosomes on angiogenesis under hypoxic conditions. METHODS: Effects of miR-1825 mimic/inhibitor as well as hypoxia-induced tumor derived exosomes on human umbilical vein endothelial cells (HUVECs) were evaluated using cell viability, migration/invasion, tube formation, and spheroid-based 3D angiogenesis assays. RESULTS: Hypoxic conditions caused significant increase in miR-1825 levels in OSCC cells and hiTDEs. miR-1825 alone and within hiTDEs promoted endothelial cell viability, migration, invasion, and angiogenic potential, which is reversed via inhibition of miR-1825 expression. miR-1825 within hiTDEs altered the angiogenesis potential of HUVEC cells via deregulation of TSC2/mTOR axis. CONCLUSIONS: We showed that hypoxia led to OSCC-derived exosome mediated transfer of miR-1825 to HUVECs and enhanced angiogenesis in OSCC in vitro.

ZLDI-8 suppresses angiogenesis and vasculogenic mimicry in drug-resistant NSCLC in vitro and in vivo.

AIMS: The chemotherapy drugs for NSCLC often face the consequences of treatment failure due to acquired drug resistance. Tumor chemotherapy resistance is often accompanied by angiogenesis. Here, we aimed to investigate the effect and underlying mechanisms of ADAM-17 inhibitor ZLDI-8 we found before on angiogenesis and vasculogenic mimicry(VM) in drug-resistant NSCLC. MAIN METHODS: The tube formation assay was used to evaluate angiogenesis and VM. Migration and invasion were assessed with transwell assays in the co-culture condition. To explore the underlying mechanisms of how ZLDI-8 inhibited tubes formation, ELISA assay and western blot assay were preformed. The effects of ZLDI-8 on angiogenesis in vivo were investigated in Matrigel plug, CAM and Rat aortic ring assays. KEY FINDINGS: In the present study, ZLDI-8 significantly inhibited the tube formation of human umbilical vein endothelial cells (HUVECs) in either normal medium or in tumor supernatants. Furthermore, ZLDI-8 also inhibited VM tubes formation of A549/Taxol cells. In the co-culture assay, the interaction between lung cancer cells and HUVECs promotes increased cell migration and invasion, while ZLDI-8 eliminates this promotion. Moreover, the VEGF secretion were decreased by ZLDI-8 and the expression of Notch1, Dll4, HIF1α and VEGF were inhibited by ZLDI-8. In addition, ZLDI-8 can inhibit blood vessel formation in the Matrigel plug, CAM and Rat aortic ring assays. SIGNIFICANCE: ZLDI-8 inhibits angiogenesis and VM in drug-resistant NSCLC through suppressing Notch1-HIF1α-VEGF signaling pathway. This study lays the foundation for the discovery of drugs that inhibit angiogenesis and VM in drug resistant NSCLC.

Investigating Trans-differentiation of Glioblastoma Cells in an In Vitro 3D Model of the Perivascular Niche.

Glioblastoma multiforme (GBM) is the deadliest form of brain cancer, responsible for over 50% of adult brain tumors. A specific region within the GBM environment is known as the perivascular niche (PVN). This area is defined as within approximately 100 µm of vasculature and plays an important role in the interactions between endothelial cells (ECs), astrocytes, GBM cells, and stem cells. We have designed a 3D in vitro model of the PVN comprising either collagen Type 1 or HyStem-C, human umbilical vein ECs (HUVECs), and LN229 (GBM) cells. HUVECs were encapsulated within the hydrogels to form vascular networks. After 7 days, LN229 cells were co-cultured to investigate changes in both cell types. Over a 14 day culture period, we measured alterations in HUVEC networks, the contraction of the hydrogels, trans-differentiation of LN229 cells, and the concentrations of two chemokines; CXCL12 and TGF-ß. Increased cellular proliferation ranging from 10- to 16-fold was exhibited in co-cultures from days 8 to 14. This was accompanied with a decrease in the height of hydrogels of up to 68%. These changes in the biomaterial scaffold indicate that LN229-HUVEC interactions promote changes to the matrix. TGF-ß and CXCL12 secretion increased approximately 2-2.6-fold each from day 8 to 14 in all co-cultures. The expression of CXCL12 correlated with cell colocalization, indicating a chemotactic role in enabling the migration of LN229 cells toward HUVECs in co-cultures. von Willebrand factor (vWF) was co-expressed with glial fibrillary acidic protein (GFAP) in up to 15% of LN229 cells after 24 h in co-culture. Additionally, when LN229 cells were co-cultured with human brain microvascular ECs, the percentages of GFAP+/vWF+ cells were up to 20% higher than that in co-cultures with HUVECs in collagen (2.2 mg/mL) and HyStem-C gels on day 14. The expression of vWF indicates the early stages of trans-differentiation of LN229 cells to an EC phenotype. Designing in vitro models of trans-differentiation may provide additional insights into how vasculature and cellular phenotypes are altered in GBM.

Phosphoenolpyruvate induces endothelial dysfunction and cell senescence through stimulation of metabolic reprogramming.

Endothelial dysfunction is a key early link in the pathogenesis of atherosclerosis, and the accumulation of senescent vascular endothelial cells causes endothelial dysfunction. Phosphoenolpyruvate (PEP), which is a high-energy glycolytic intermediate, protects against ischemia-reperfusion injury in isolated rat lung, heart, and liver tissue by quickly providing ATP. However, it was reported that serum PEP concentrations are 13-fold higher in healthy elderly compare to the young. Unlike that of other cell types, the energy required for the physiological function of endothelial cells is mainly derived from glycolysis. Recently, it is unclear whether circulating accumulation of PEP affects endothelial cell function. In this study, we found for the first time that 50-250 µM of PEP significantly promoted THP-1 monocyte adhesion to human umbilical vein endothelial cells (HUVECs) through increased expression of vascular endothelial adhesion factor 1 (VCAM1) and intercellular adhesion factor 1 (ICAM1) in HUVECs. Meanwhile, 50-250 µM of PEP decreased the expression of endothelial nitric oxide synthase (eNOS) and cellular level of nitric oxide (NO) in HUVECs. Moreover, PEP increased levels of ROS, enhanced the numbers of SA-ß-Gal-positive cells and upregulated the expression of cell cycle inhibitors such as p21, p16 and the phosphorylation level of p53 on Ser15, and the expression of proinflammatory factors including TNF-α, IL-1ß, IL-6, IL-8, IL-18 and MCP-1 in HUVECs. Furthermore, PEP increased both oxygen consumption rate (OCR) and glycolysis rate, and was accompanied by reduced NAD+/NADH ratios and enhanced phosphorylation levels of AMPKα (Thr172), p38 MAPK (T180/Y182) and NF-κB p65 (Ser536) in HUVECs. Notably, PEP had no significant effect on hepG2 cells. In conclusion, these results demonstrated that PEP induced dysfunction and senescence in vascular endothelial cells through stimulation of metabolic reprogramming.

STIM1-regulated exosomal EBV-LMP1 empowers endothelial cells with an aggressive phenotype by activating the Akt/ERK pathway in nasopharyngeal carcinoma.

BACKGROUND: Stromal interaction molecule 1 (STIM1)-mediated Ca2+ signaling regulates tumor angiogenesis in nasopharyngeal carcinoma (NPC), an Epstein-Barr virus (EBV)-related human malignancy. However, the mechanism by which STIM1 modulates endothelial functional phenotypes contributing to tumor angiogenesis remains elusive. METHODS: NPC cell-derived exosomes were isolated via differential centrifugation and observed using transmission electron microscopy. Exosome particle sizes were assessed by nanoparticle tracking analysis (NTA). Uptake of exosomes by recipient ECs was detected by fluorescent labeling of the exosomes with PKH26. Tumor angiogenesis-associated profiles were characterized by determining cell proliferation, migration, tubulogenesis and permeability in human umbilical vein endothelial cells (HUVECs). Activation of the Akt/ERK pathway was assessed by detecting the phosphorylation levels using Western blotting. A chick embryo chorioallantoic membrane (CAM) xenograft model was employed to study tumor-associated neovascularization in vivo. RESULTS: We found that NPC cell-derived exosomes harboring EBV-encoded latent membrane protein 1 (LMP1) promoted proliferation, migration, tubulogenesis and permeability by activating the Akt/ERK pathway in ECs. STIM1 silencing reduced LMP1 enrichment in NPC cell-derived exosomes, thereby reversing its pro-oncogenic effects in an Akt/ERK pathway-dependent manner. Furthermore, STIM1 knockdown in NPC cells blunted tumor-induced vascular network formation and inhibited intra-tumor neovascularization in the chorioallantoic membrane (CAM) xenograft model. CONCLUSION: STIM1 regulates tumor angiogenesis by controlling exosomal EBV-LMP1 delivery to ECs in the NPC tumor microenvironment. Blocking exosome-mediated cell-to-cell horizontal transfer of EBV-associated oncogenic signaling molecules may be an effective therapeutic strategy for NPC.

LncRNA NIPA1-SO confers atherosclerotic protection by suppressing the transmembrane protein NIPA1.

Long non-coding RNAs (lncRNAs) are emerging as important players in gene regulation and cardiovascular diseases. However, the roles of lncRNAs in atherosclerosis are poorly understood. In the present study, we found that the levels of NIPA1-SO were decreased while those of NIPA1 were increased in human atherosclerotic plaques. Furthermore, NIPA1-SO negatively regulated NIPA1 expression in human umbilical vein endothelial cells (HUVECs). Mechanistically, NIPA1-SO interacted with the transcription factor FUBP1 and the NIPA1 gene. The effect of NIPA1-SO on NIPA1 protein levels was reversed by the knockdown of FUBP1. NIPA1-SO overexpression increased, whilst NIPA1-SO knockdown decreased BMPR2 levels; these effects were enhanced by the knockdown of NIPA1. The overexpression of NIPA1-SO reduced while NIPA1-SO knockdown increased monocyte adhesion to HUVECs; these effects were diminished by the knockdown of BMPR2. The lentivirus-mediated-overexpression of NIPA1-SO or gene-targeted knockout of NIPA1 in low-density lipoprotein receptor-deficient mice reduced monocyte-endothelium adhesion and atherosclerotic lesion formation. Collectively, these findings revealed a novel anti-atherosclerotic role for the lncRNA NIPA1-SO and highlighted its inhibitory effects on vascular inflammation and intracellular cholesterol accumulation by binding to FUBP1 and consequently repressing NIPA1 expression.

Connexin43 overexpression promotes bone regeneration by osteogenesis and angiogenesis in rat glucocorticoid-induced osteonecrosis of the femoral head.

Glucocorticoids induced osteonecrosis of the femoral head (GIONFH) is a devastating orthopedic disease. Previous studies suggested that connexin43 is involved in the process of osteogenesis and angiogenesis. However, the role of Cx43 potentiates in the osteogenesis and angiogenesis of bone marrow-derived stromal stem cells (BMSCs) in GIONFH is still not investigated. In this study, BMSCs were isolated and transfected with green fluorescent protein or the fusion gene encoding GFP and Cx43. The osteogenic differentiation of BMSCs were detected after transfected with Cx43. In addition, the migration abilities and angiogenesis of human umbilical vein endothelial cells (HUVECs) were been detected after induced by transfected BMSCs supernatants in vitro. Finally, we established GC-ONFH rat model, then, a certain amount of transfected or controlled BMSCs were injected into the tibia of the rats. Immunohistological staining and micro-CT scanning results showed that the transplanted experiment group had significantly promoted more bone regeneration and vessel volume when compared with the effects of the negative or control groups. This study demonstrated for the first time that the Cx43 overexpression in BMSCs could promote bone regeneration as seen in the osteogenesis and angiogenesis process, suggesting that Cx43 may serve as a therapeutic gene target for GIONFH treatment.

Osteopontin mediation of disturbed flow-induced endothelial mesenchymal transition through CD44 is a novel mechanism of neointimal hyperplasia in arteriovenous fistulae for hemodialysis access.

In dysfunctional arteriovenous fistulae (AVF) for hemodialysis access, neointimal hyperplasia (NH) is prone to occur in the region exposed to disturbed flow. We hypothesized that disturbed flow contributes to NH in AVF by inducing endothelial mesenchymal transition (EndMT) through activation of the osteopontin/CD44 axis. In rats with aortocaval fistula, a rodent model of AVF, we demonstrated development of EndMT and expression of osteopontin and CD44 specifically in the vicinity of the arteriovenous junction using immunostaining. Duplex scan confirmed this region was exposed to a disturbed flow. A mixed ultrastructural phenotype of endothelium and smooth muscle cells was found in luminal endothelial cells of the arteriovenous junction by electron microscopy ascertaining the presence of EndMT. Endothelial lineage tracing using Cdh5-Cre/ERT2;ROSA26-tdTomato transgenic mice showed that EndMT was involved in NH of AVF since the early stage and that the endothelial-derived cells contributed to 24% of neointimal cells. In human umbilical vein endothelial cells (HUVECs) in culture, osteopontin treatment induced EndMT, which was suppressed by CD44 knockdown. Exposure to low oscillatory wall shear stress using a parallel-plate system induced EndMT in HUVECs, also suppressed by osteopontin or CD44 knockdown. In AVF of CD44 knockout mice, EndMT was mitigated and NH decreased by 35% compared to that in wild-type mice. In dysfunctional AVF of patients with uremia, expressions of osteopontin, CD44, and mesenchymal markers in endothelial cells overlying the neointima was also found by immunostaining. Thus, the osteopontin/CD44 axis regulates disturbed flow-induced EndMT, plays an important role in neointimal hyperplasia of AVF, and may act as a potential therapeutic target to prevent AVF dysfunction.

Bone marrow stromal cell-derived exosomal circular RNA improves diabetic foot ulcer wound healing by activating the nuclear factor erythroid 2-related factor 2 pathway and inhibiting ferroptosis.

BACKGROUND: Diabetic foot ulcer (DFU) remains a serious chronic diabetic complication that can lead to disability. CircRNA-itchy E3 ubiquitin protein ligase (circ-ITCH) was observed to be down-regulated in diabetic retinopathy and diabetic nephropathy, and overexpression of circ-ITCH could inhibit the processes of these diseases. However, the detailed physiological and pathological functions of circ-ITCH in wound healing of DFU remain undetermined. METHODS: Exosomes derived from bone marrow stromal cells (BMSCs) were isolated and identified. Cell viability and angiogenesis of human umbilical vein endothelial cells (HUVECs) were evaluated by cell counting kit-8 (CCK-8) and tube formation assays, respectively. The interplays of circ-ITCH, TATA-Box-binding protein associated factor 15 (TAF15) and nuclear factor erythroid 2-related factor 2 (Nrf2) mRNA were analysed by RNA immunoprecipitation (RIP), fluorescence in situ hybridization (FISH) combined immunofluorescent staining and RNA pull-down assays. qRT-PCR, western blot or immunohistochemistry (IHC) were used to measure the expression of circ-ITCH, TAF15, Nrf2, vascular endothelial growth factor (VEGFR) and ferroptosis-related makers. The mice DFU model was established to verify the in vitro results. RESULTS: Circ-ITCH was down-regulated in in vitro and in vivo models of DFU. Deferoxamine (DFO), an iron chelating agent, improved the viability and angiogenic ability of high glucose (HG)-treated HUVECs. Overexpression of circ-ITCH or co-cultured with exosomal circ-ITCH from BMSCs could alleviate HG-induced ferroptosis and improve the angiogenesis ability of HUVECs. Circ-ITCH in HUVECs recruited TAF15 protein to stabilize Nrf2 mRNA, thus activating the Nrf2 signalling pathway and suppressing ferroptosis. Exosomal circ-ITCH from BMSCs also accelerated the wound healing process by inhibiting ferroptosis in the DFU mice in a time-dependent manner. CONCLUSION: Exosomal circ-ITCH from BMSCs inhibited ferroptosis and improved the angiogenesis of HUVECs through activation of the Nrf2 signalling pathway by recruiting TAF15 protein, ultimately accelerating the wound healing process in DFU.