Signaling Pathway In Endothelial Cells Research Articles

PDPN/CCL2/STAT3 feedback loop alter CAF heterogeneity to promote angiogenesis in colorectal cancer.

Colorectal cancer (CRC) is one of the common clinical malignancies and the fourth leading cause of cancer-related death in the world. The tumor microenvironment (TME) plays a crucial role in promoting tumor angiogenesis, and cancer-associated fibroblasts (CAFs) are one of the key components of the tumor microenvironment. However, due to the high heterogeneity of CAFs, elucidating the molecular mechanism of CAF-mediated tumor angiogenesis remained elusive. In our study, we found that there is pro-angiogenic functional heterogeneity of CAFs in colorectal cancer and we clarified that Podoplanin (PDPN) can specifically label CAF subpopulations with pro-angiogenic functions. We also revealed that PDPN + CAF could maintain CAF heterogeneity by forming a PDPN/CCL2/STAT3 feedback loop through autocrine CCL2, while activate STAT3 signaling pathway in endothelial cells to promote angiogenesis through paracrine CCL2. We demonstrated WP1066 could inhibit colorectal cancer angiogenesis by blocking both the PDPN/CCL2/STAT3 feedback loop in CAFs and the STAT3 signaling pathway in endothelial cells. Altogether, our study suggests that STAT3 could be a potential therapeutic target for blocking angiogenesis in colorectal cancer. We provide theoretical basis and new therapeutic strategies for the clinical treatment of colorectal cancer.

Control of inflammatory lung injury and repair by metabolic signaling in endothelial cells.

Sepsis-induced inflammatory lung injury includes acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). There are currently no effective treatments for ALI/ARDS, but clinical outcomes could be improved by inhibiting lung injury and/or promoting post-sepsis vascular repair. In this review, we describe studies of endothelial cell metabolic pathways in sepsis-induced ALI/ARDS and vascular repair and identify areas of research that deserve attention in future studies. We also describe studies of metabolic interventions that aim to inhibit ALI/ARDS and/or promote post-sepsis vascular repair, including those that target endothelial cell metabolites, endothelial cell metabolic signaling pathways, and endothelial cell metabolism. Endothelial cells are integral to both the injury and repair phases of ALI/ARDS. During the injury phase of ALI/ARDS, lung endothelial cell survival decreases, and lung endothelial cell-to-endothelial cell (EC-EC) junctions are weakened. During the repair phase after sepsis-induced lung injury, lung endothelial cell proliferation and lung EC-EC junction reannealing occur. These crucial aspects of ALI/ARDS and post-sepsis vascular repair, that is, endothelial cell viability, growth, and junction integrity, are controlled by a myriad of metabolites and metabolic signaling pathways in endothelial cells. Metabolic signaling pathways in endothelial cells represent a novel class of putative targets for the prevention and treatment of sepsis-induced inflammatory lung injury. Therapies that target metabolic signaling in endothelial cells are currently being explored as potential treatments for sepsis-induced inflammatory lung injury.

Pleiotrophin Activates cMet- and mTORC1-Dependent Protein Synthesis through PTPRZ1-The Role of ανβ3 Integrin.

Pleiotrophin (PTN) is a secreted factor that regulates endothelial cell migration through protein tyrosine phosphatase receptor zeta 1 (PTPRZ1) and αvβ3 integrin. Genetic deletion of Ptprz1 results in enhanced endothelial cell proliferation and migration, due to the decreased expression of β3 integrin and the subsequent, enhanced cMet phosphorylation. In the present study, we investigated the effect of PTN and PTPRZ1 on activating the mTORC1 kinase and protein synthesis and identified part of the implicated signaling pathway in endothelial cells. PTN or genetic deletion of Ptprz1 activates protein synthesis in a mTORC1-dependent manner, as shown by the enhanced phosphorylation of the mTORC1-downstream targets ribosomal protein S6 kinase 1 (SK61) and 4E-binding protein 1 (4EBP1) and the upregulation of HIF-1α. The cMet tyrosine kinase inhibitor crizotinib abolishes the stimulatory effects of PTN or PTPRZ1 deletion on mTORC1 activation and protein synthesis, suggesting that mTORC1 activation is downstream of cMet. The mTORC1 inhibitor rapamycin abolishes the stimulatory effect of PTN or PTPRZ1 deletion on endothelial cell migration, suggesting that mTORC1 is involved in the PTN/PTPRZ1-dependent cell migration. The αvβ3 integrin blocking antibody LM609 and the peptide PTN112-136, both known to bind to ανβ3 and inhibit PTN-induced endothelial cell migration, increase cMet phosphorylation and activate mTORC1, suggesting that cMet and mTORC1 activation are required but are not sufficient to stimulate cell migration. Overall, our data highlight novel aspects of the signaling pathway downstream of the PTN/PTPRZ1 axis that regulates endothelial cell functions.

Angiotensin II depends on hippo/YAP signaling to reprogram angiogenesis and promote liver fibrosis

Liver fibrosis is a chronic pathological process in which the abnormal proliferation of connective tissue is induced by various pathogenic factors. During the process of fibrosis, excessive angiogenesis is observed. Physiological angiogenesis has the potential to impede the progression of liver fibrosis through augmenting matrix metalloenzyme activity; however, pathological angiogenesis can exacerbate liver fibrosis by promoting collagen accumulation. Therefore, a key scientific research focus in the treatment of liver diseases is to search for the “on-off” mechanism that regulates angiogenesis from normal proliferation to pathological proliferation. In this study, we found that excessive angiogenesis appeared during the initial phase of hepatic fibrosis without mesenchymal characteristics. In addition, angiogenesis accompanied by significant endothelial-to-mesenchymal transition (EndMT) was observed in mice after the intraperitoneal injection of angiotensin II (Ang II). Interestingly, the changes in Yes-associated protein (YAP) activity in endothelial cells (ECs) can affect the regulation of angiogenesis by Ang II. The results of in vitro experiments revealed that the regulatory influence of Ang II on ECs was significantly attenuated upon suppression of YAP activity. Furthermore, the function of Ang II in regulating angiogenesis during fibrosis was investigated in liver-specific transgenic mice. The results revealed that Ang II gene deletion could restrain liver fibrosis and EndMT. Meanwhile, Ang II deletion downregulated the profibrotic YAP signaling pathway in ECs. The small molecule AT1R agonist olmesartan targeting Ang II-YAP signaling could also alleviate liver fibrosis. In conclusion, this study identified Ang II as a pivotal regulator of EndMT during the progression of liver fibrosis and evaluated the therapeutic effect of the Ang II-targeted drug olmesartan on liver fibrosis.

Coronary Microvascular Dysfunction is Associated with Augmented Lysosomal Signaling in Hypercholesterolemic Mice.

Accumulating evidence indicates that coronary microvascular dysfunction (CMD) caused by hypercholesterolemia can lead to myocardial ischemia, with or without obstructive atherosclerotic coronary artery disease (CAD). However, the molecular pathways associated with compromised coronary microvascular function prior to the development of myocardial ischemic injury remain poorly defined. In this study, we investigated the effects of hypercholesterolemia on the function and integrity of the coronary microcirculation in mice and the underlying mechanisms. Mice were fed with a hypercholesterolemic Paigen's diet (PD) for 8 weeks. Echocardiography data showed that PD caused CMD, characterized by significant reductions in coronary blood flow and coronary flow reserve (CFR), but did not affect cardiac remodeling or dysfunction. Immunofluorescence studies revealed that PD-induced CMD was associated with activation of coronary arterioles inflammation and increased myocardial inflammatory cell infiltration. These pathological changes occurred in parallel with the upregulation of lysosomal signaling pathways in endothelial cells (ECs). Treating hypercholesterolemic mice with the cholesterol-lowering drug ezetimibe significantly ameliorated PD-induced adverse effects, including hypercholesterolemia, steatohepatitis, reduced CFR, coronary EC inflammation, and myocardial inflammatory cell infiltration. In cultured mouse cardiac endothelial cells (MCECs), 7-ketocholesterol (7K) increased mitochondrial reactive oxygen species (ROS) and inflammatory responses. Meanwhile, 7K induced the activation of TFEB and lysosomal signaling in MCECs, whereas the lysosome inhibitor bafilomycin A1 blocked 7K-induced TFEB activation and exacerbated 7K-induced inflammation and cell death. Interestingly, ezetimibe synergistically enhanced 7K-induced TFEB activation and attenuated 7K-induced mitochondrial ROS and inflammatory responses in MCECs. These results suggest that CMD can develop and precede detectable cardiac functional or structural changes in the setting of hypercholesterolemia, and that upregulation of TFEB-mediated lysosomal signaling in ECs plays a protective role against CMD.

The comparative analysis of Vascular Endothelial Growth Factor-A (VEGF-A) impacts in Ovarian Hyper Stimulation Syndrome and Obesity

Ovarian Hyper Stimulation Syndrome (OHSS) is an iatrogenic complication that arises during in-vitro fertilization (IVF) procedures for infertility treatment, representing a growing global concern. This disorder is characterized by several risk factors, clinical features and laboratory manifestations. The underlying pathophysiology involves proinflammatory mediators, with VEGF-A playing a pivotal role. VEGF-A significantly impacts vasculature and contributes to the resulting pathophysiology of OHSS and other related diseases. Interestingly, obesity, another example, demonstrates distinct VEGF-A effects on vasculature, differing from its role in OHSS. In this review article, our aim is to describe pathophysiology of OHSS and obesity as well as providing updated insights into these disorders, highlighting how VEGF-A modulates vasculature through unique intracellular signaling pathways in endothelial cells.

Anthrahydroquinone‑2,6‑disulfonate attenuates PQ‑induced acute lung injury through decreasing pulmonary microvascular permeability via inhibition of the PI3K/AKT/eNOS pathway.

In paraquat (PQ)‑induced acute lung injury (ALI)/ acute respiratory distress syndrome, PQ disrupts endothelial cell function and vascular integrity, which leads to increased pulmonary leakage. Anthrahydroquinone‑2,6‑disulfonate (AH2QDS) is a reducing agent that attenuates the extent of renal injury and improves survival in PQ‑intoxicated Sprague‑Dawley (SD) rats. The present study aimed to explore the beneficial role of AH2QDS in PQ‑induced ALI and its related mechanisms. A PQ‑intoxicated ALI model was established using PQ gavage in SD rats. Human pulmonary microvascular endothelial cells (HPMECs) were challenged with PQ. Superoxide dismutase, malondialdehyde, reactive oxygen species and nitric oxide (NO) fluorescence were examined to detect the level of oxidative stress in HPMECs. The levels of TNF‑α, IL‑1β and IL‑6 were assessed using an ELISA. Transwell and Cell Counting Kit‑8 assays were performed to detect the migration and proliferation of the cells. The pathological changes in lung tissues and blood vessels were examined by haematoxylin and eosin staining. Evans blue staining was used to detect pulmonary microvascular permeability. Western blotting was performed to detect target protein levels. Immunofluorescence and immunohistochemical staining were used to detect the expression levels of target proteins in HPMECs and lung tissues. AH2QDS inhibited inflammatory responses in lung tissues and HPMECs, and promoted the proliferation and migration of HPMECs. In addition, AH2QDS reduced pulmonary microvascular permeability by upregulating the levels of vascular endothelial‑cadherin, zonula occludens‑1 and CD31, thereby attenuating pathological changes in the lungs in rats. Finally, these effects may be related to the suppression of the phosphatidylinositol‑3‑kinase (PI3K)/protein kinase B (AKT)/endothelial‑type NO synthase (eNOS) signalling pathway in endothelial cells. In conclusion, AH2QDS ameliorated PQ‑induced ALI by improving alveolar endothelial barrier disruption via modulation of the PI3K/AKT/eNOS signalling pathway, which may be an effective candidate for the treatment of PQ‑induced ALI.

#2928 Fabry disease may imbalance integrin α3 related to endothelial dysfunction

Abstract Background and Aims Fabry Disease (FD) is a rare disease characterized by a mutation in the GLA gene and consequently by the functional anomaly of the α-Galactosidase A (α-Gal) enzyme. The lack of this functional enzyme leads to lysosomal accumulation of glycosphingolipids, mainly globotriaosylceramide (Gb3), in different cell types, causing several symptoms throughout the body, which aggravate during the patient's longevity. We already demonstrated that exposure of endothelial cells to chloroquine, to mimic FD effects, leads to lysosomal accumulation in human endothelial cells. In the present study, we analyzed the endothelial changes in ultrastructural morphology and cell adhesion under evaluation of Integrin α3 expression, an important integrin that stabilizes cell adhesion and is involved in several signaling pathways in endothelial cells. Method Human endothelial cells (EA.hy926, ATCC CRL-2922) were exposed to chloroquine diphosphate (0.5 µg/mL) for 72 hours. The ultrastructural morphology was analyzed through scanning electron microscopy (SEM) and the Integrin α3 expression was analyzed through Western Blot and RT-qPCR. Results Through SEM (Fig. 1C-F) it was observed that after the exposure to chloroquine diphosphate, there was a decrease in cell expansion and adhesion and an increase in vesicular content. Curiously, the analysis of the Integrin α3 gene (ITGA3) and protein expression (Fig. 1A-B) demonstrated a significant increase (P < 0.05) in cells that were exposed to chloroquine diphosphate compared to non-exposed cells (control cells). Conclusion The in vitro condition of the FD in human endothelial cells demonstrated an increase in Integrin α3; however, there was a decrease in cell adhesion and expansion. The evaluation of the Integrin α3 expression could be important for monitoring the endothelial dysfunction in FD, as it is intrinsically involved in cell adhesion, remodeling, and fibrosis. These important changes can lead to renal impairment, proteinuria, and decreased glomerular filtration rate.

Vascular endothelial growth factor receptor 2 contributes to shear stress-induced endothelial nitric oxide synthase expression in human lung microvascular endothelial cells

Introduction: Physiological shear stress (pSS) helps to maintain endothelial homeostasis via numerous intracellular signaling pathways. We previously showed that pSS upregulates mRNA and protein levels of endothelial nitric oxide synthase (eNOS) in primary human lung microvascular endothelial cells (hLMVECs), and that phosphorylation of Akt (p-Akt), a phosphatidylinositol 3-kinase (PI3K) target, is increased. Upstream regulatory mechanisms for these responses have not been fully studied. Since vascular endothelial growth factor receptor 2 (VEGFR2) is an integral component of the mechanosensory complex that transduces shear stress-mediated signaling pathways in endothelial cells, we hypothesized that VEGFR2 is required for shear stress-induced eNOS expression and PI3K activation in hLMVECs. Methods: We cultured early passage (p≤7) primary hLMVECs from 4 unique donor lots in standard 6-well culture plates using a fixed volume (depth) and viscosity of tissue culture media. We exposed cells to shear stress for 24 hours using an orbital shaker and calculated the magnitude of shear stress exerted on hLMVECs using the extended solution to Stokes’ second problem. We defined the magnitude of pSS as 12 dyn/cm2. In some experiments, we exposed cells to pSS in the presence of chemical inhibitors of VEGFR2 (SU5416; 5 or 10 μM) or PI3K (LY294002; 10 μM). We collected whole cell lysates and performed immunoblotting to probe for phosphorylated eNOS (p-eNOS; Serine 1177), total eNOS, p-Akt (Serine 473), total Akt and housekeeping protein β-tubulin. Potential interactions between chemical inhibitors and pSS on protein expression and phosphorylation were analyzed by two-way ANOVA. Results: After 24 hours of pSS exposure, total eNOS levels were significantly (p<0.05) increased in hLMVECs, although the p-eNOS/eNOS ratio was not changed (p=0.85). Conversely, 24 hours of pSS exposure increased the p-Akt/Akt ratio (p<0.05) but did not increase total Akt levels (p=0.88). Inhibition of VEGFR2 activity with SU5416 attenuated pSS-induced changes in total eNOS levels (p<0.05 for interaction) but did not attenuate pSS-induced increases in the p-Akt/Akt ratio (p=0.91 for interaction). Inhibition of PI3K activity using LY294002 did not modify the effects of pSS on total eNOS levels (p=0.25 for interaction) or p-Akt/Akt ratio (p=0.47 for interaction). Conclusions: We conclude that VEGFR2 activity is necessary for pSS-mediated increases in eNOS protein levels, but not PI3K activity, in hLMVECs. Furthermore, neither VEGFR2 nor PI3K activity appear to be required for pSS-mediated eNOS phosphorylation in these cells. Collectively, these data suggest that shear stress regulates hLMVEC eNOS signaling via multiple signaling pathways. This complex regulation may have important implications for local nitric oxide bioavailability under pathological conditions that modify shear stress (e.g., pulmonary embolism, pulmonary hypertension). This work is supported by NIH grants HL126514 and HL159906. This is the full abstract presented at the American Physiology Summit 2024 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.

Fuyuan decoction prevents nasopharyngeal carcinoma metastasis by inhibiting circulating tumor cells/ endothelial cells interplay and enhancing anti-cancer immune response.

Distant metastasis is a major cause of treatment failure in cancer patients and a key challenge to improving cancer care today. We hypothesized that enhancing anti-cancer immune response and inhibiting circulating tumor cells (CTCs) adhesion and transendothelial migration through synergistic multi-target approaches may effectively prevent cancer metastasis. "Fuyuan Decoction" (FYD) is a traditional Chinese medicine compound that is widely used to prevent postoperative metastasis in cancer patients, but its underlying mechanism remains unclear. In this work, we systematically elucidated the underlying molecular mechanism by which FYD prevents cancer metastasis through multi-compound and multi-target synergies in vitro and in vivo. FYD significantly prevented cancer metastasis at non-cytotoxic concentrations by suppressing the adhesion of CTCs to endothelial cells and their subsequent transendothelial migration, as well as enhancing anti-cancer immune response. Mechanistically, FYD interrupts adhesion of CTCs to vascular endothelium by inhibiting TNF-α-induced CAMs expression via regulation of the NF-κB signaling pathway in endothelial cells. FYD inhibits invasion and migration of CTCs by suppressing EMT, PI3K/AKT and FAK signaling pathways. Moreover, FYD enhances the anti-cancer immune response by significantly increasing the population of Tc and NK cells in the peripheral immune system. In addition, the chemical composition of FYD was determined by UPLC-HRMS, and the results indicated that multiple compounds in FYD prevents cancer metastasis through multi-target synergistic treatment. This study provides a modern medical basis for the application of FYD in the prevention of cancer metastasis, and suggesting that multi-drug and multi-target synergistic therapy may be one of the most effective ways to prevent cancer metastasis.

Engineered Wnt7a ligands rescue blood-brain barrier and cognitive deficits in a COVID-19 mouse model.

Respiratory infection with SARS-CoV-2 causes systemic vascular inflammation and cognitive impairment. We sought to identify the underlying mechanisms mediating cerebrovascular dysfunction and inflammation following mild respiratory SARS-CoV-2 infection. To this end, we performed unbiased transcriptional analysis to identify brain endothelial cell signalling pathways dysregulated by mouse adapted SARS-CoV-2 MA10 in aged immunocompetent C57Bl/6 mice in vivo. This analysis revealed significant suppression of Wnt/β-catenin signalling, a critical regulator of blood-brain barrier (BBB) integrity. We therefore hypothesized that enhancing cerebrovascular Wnt/β-catenin activity would offer protection against BBB permeability, neuroinflammation, and neurological signs in acute infection. Indeed, we found that delivery of cerebrovascular-targeted, engineered Wnt7a ligands protected BBB integrity, reduced T-cell infiltration of the brain, and reduced microglial activation in SARS-CoV-2 infection. Importantly, this strategy also mitigated SARS-CoV-2 induced deficits in the novel object recognition assay for learning and memory and the pole descent task for bradykinesia. These observations suggest that enhancement of Wnt/β-catenin signalling or its downstream effectors could be potential interventional strategies for restoring cognitive health following viral infections.

Single-cell RNA-seq analysis decodes the kidney microenvironment induced by polystyrene microplastics in mice receiving a high-fat diet

In recent years, the environmental health issue of microplastics has aroused an increasingly significant concern. Some studies suggested that exposure to polystyrene microplastics (PS-MPs) may lead to renal inflammation and oxidative stress in animals. However, little is known about the essential effects of PS-MPs with high-fat diet (HFD) on renal development and microenvironment. In this study, we provided the single-cell transcriptomic landscape of the kidney microenvironment induced by PS-MPs and HFD in mouse models by unbiased single-cell RNA sequencing (scRNA-seq). The kidney injury cell atlases in mice were evaluated after continued PS-MPs exposure, or HFD treated for 35 days. Results showed that PS-MPs plus HFD treatment aggravated the kidney injury and profibrotic microenvironment, reshaping mouse kidney cellular components. First, we found that PS-MPs plus HFD treatment acted on extracellular matrix organization of renal epithelial cells, specifically the proximal and distal convoluted tubule cells, to inhibit renal development and induce ROS-driven carcinogenesis. Second, PS-MPs plus HFD treatment induced activated PI3K-Akt, MAPK, and IL-17 signaling pathways in endothelial cells. Besides, PS-MPs plus HFD treatment markedly increased the proportions of CD8+ effector T cells and proliferating T cells. Notably, mononuclear phagocytes exhibited substantial remodeling and enriched in oxidative phosphorylation and chemical carcinogenesis pathways after PS-MPs plus HFD treatment, typified by alterations tissue-resident M2-like PF4+ macrophages. Multispectral immunofluorescence and immunohistochemistry identified PF4+ macrophages in clear cell renal cell carcinoma (ccRCC) and adjacent normal tissues, indicating that activate PF4+ macrophages might regulate the profibrotic and pro-tumorigenic microenvironment after renal injury. In conclusion, this study first systematically revealed molecular variation of renal cells and immune cells in mice kidney microenvironment induced by PS-MPs and HFD with the scRNA-seq approach, which provided a molecular basis for decoding the effects of PS-MPs on genitourinary injury and understanding their potential profibrotic and carcinogenesis in mammals.Graphical

NeuroD1 Regulated Endothelial Gene Expression to Modulate Transduction of AAV-PHP.eB and Recovery Progress after Ischemic Stroke.

AAV-PHP.eB depends on endothelial cells to highly transduce the central nervous system (CNS) and is widely used for intravenous gene therapy. However, the transduction profile and therapeutic efficiency after endothelial cell injury such as ischemic stroke is largely unknown. In this study, we tested the transduction profiles of AAV-PHP.eB and developed intravenous NeuroD1 gene therapy to treat ischemic stroke in mice. We found that AAV-PHP.eB-GFP control virus crossed the BBB and infected brain cells efficiently in normal brain. However, after stroke, AAV-PHP.eB-GFP control virus was highly restricted in the blood vessels. Surprisingly, after switching to therapeutic vector AAV-PHP.eB-NeuroD1-GFP, the viral vector successfully crossed blood vessels and infected brain cells. Using Tie2-cre transgenic mice, we demonstrated that NeuroD1 regulated endothelial gene expression to modulate AAV-PHP.eB transduction. Following the changes of signaling pathways in endothelial cells, NeuroD1 effectively protected BBB integrity, attenuated neuroinflammation, inhibited neuron apoptosis and rescued motor deficits after ischemic stroke. Moreover, NeuroD1 over-expression in brain cells further promoted neural regeneration. These results indicate that intravenous gene therapy using AAV-PHP.eB for ischemic stroke differs from intracranial gene therapy and NeuroD1 intravenous delivery using AAV-PHP.eB efficiently rescue both vascular damage and neuronal loss, providing an advancing therapeutic treatment for stroke.

Modulation of SEMA4D-modified titanium surface on M2 macrophage polarization via activation of Rho/ROCK-mediated lactate release of endothelial cells: In vitro and in vivo

SEMA4D-modified titanium surfaces can indirectly regulate macrophages through endothelial cells to achieve an anti-inflammatory effect, which is beneficial for healing soft tissues around the gingival abutment. However, the mechanism of surface-induced cellular phenotypic changes in SEMA4D-modified titanium has not yet been elucidated. SEMA4D activates the RhoA signaling pathway in endothelial cells, which coordinates metabolism and cytoskeletal remodeling. This study hypothesized that endothelial cells inoculated on SEMA4D-modified titanium surfaces can direct M2 polarization of macrophages via metabolites. An indirect co-culture model of endothelial cells and macrophages was constructed in vitro, and specific inhibitors were employed. Subsequently, endothelial cell adhesion and migration, metabolic changes, Rho/ROCK1 expression, and inflammatory expression of macrophages were assessed via immunofluorescence microscopy, specific kits, qRT-PCR, and Western blotting. Moreover, an in vivo rat bilateral maxillary implant model was constructed to evaluate the soft tissue healing effect. The in vitro experiments showed that the SEMA4D group had stronger endothelial cell adhesion and migration, increased Rho/ROCK1 expression, and enhanced release of lactate. Additionally, decreased macrophage inflammatory expression was observed. In contrast, the inhibitor group partially suppressed lactate metabolism and motility, whereas increased inflammatory expression. The in vivo analyses indicated that the SEMA4D group had faster and better angiogenic and anti-inflammatory effects, especially in the early stage. In conclusion, via the Rho/ROCK1 signaling pathway, the SEMA4D-modified titanium surface promotes endothelial cell adhesion and migration and lactic acid release, then the paracrine lactic acid promotes the polarization of macrophages to M2, thus obtaining the dual effects of angiogenesis and anti-inflammation.

The bisphosphonates alendronate and zoledronate induce adaptations of aerobic metabolism in permanent human endothelial cells

Nitrogen-containing bisphosphonates (NBPs), compounds that are widely used in the treatment of bone disorders, may cause side effects related to endothelial dysfunction. The aim of our study was to investigate the effects of chronic 6-day exposure to two common bone-preserving drugs, alendronate and zoledronate, on endothelial function and oxidative metabolism of cultured human endothelial cells (EA.hy926). NBPs reduced cell viability, induced oxidative stress and a pro-inflammatory state and downregulated the prenylation-dependent ERK1/2 signaling pathway in endothelial cells. In addition, NBPs induced increased anaerobic respiration and slightly increased oxidative mitochondrial capacity, affecting mitochondrial turnover through reduced mitochondrial fission. Moreover, by blocking the mevalonate pathway, NBPs caused a significant decrease in the level of coenzyme Q10, thereby depriving endothelial cells of an important antioxidant and mitochondrial electron carrier. This resulted in increased formation of reactive oxygen species (ROS), upregulation of antioxidant enzymes, and impairment of mitochondrial respiratory function. A general decrease in mitochondrial respiration occurred with stronger reducing fuels (pyruvate and glutamate) in NBP-treated intact endothelial cells, and significantly reduced phosphorylating respiration was observed during the oxidation of succinate and especially malate in NBP-treated permeabilized endothelial cells. The observed changes in oxidative metabolism caused a decrease in ATP levels and an increase in oxygen levels in NBP-treated cells. Thus, NBPs modulate the energy metabolism of endothelial cells, leading to alterations in the cellular energy state, coenzyme Q10 redox balance, mitochondrial respiratory function, and mitochondrial turnover.

Rnd3 suppresses endothelial cell pyroptosis in atherosclerosis through regulation of ubiquitination of TRAF6.

As the main pathological basis for various cardiovascular and cerebrovascular diseases, atherosclerosis has become one of the leading causes of death and disability worldwide. Emerging evidence has suggested that Rho GTPase Rnd3 plays an indisputable role in cardiovascular diseases, although its function in atherosclerosis remains unclear. Here, we found a significant correlation between Rnd3 and pyroptosis of aortic endothelial cells (ECs). ApoeKO mice were utilized as a model for atherosclerosis. Endothelium-specific transgenic mice were employed to disrupt the expression level of Rnd3 in vivo. Mechanistic investigation of the impact of Rnd3 on endothelial cell pyroptosis was carried out using liquid chromatography tandem mass spectrometry (LC-MS/MS), co-immunoprecipitation (Co-IP) assays, and molecular docking. Evidence from gain-of-function and loss-of-function studies denoted a protective role for Rnd3 against ECs pyroptosis. Downregulation of Rnd3 sensitized ECs to pyroptosis under oxidized low density lipoprotein (oxLDL) challenge and exacerbated atherosclerosis, while overexpression of Rnd3 effectively prevented these effects. LC-MS/MS, Co-IP assay, and molecular docking revealed that Rnd3 negatively regulated pyroptosis signaling by direct interaction with the ring finger domain of tumor necrosis factor receptor-associated factor 6 (TRAF6). This leads to the suppression of K63-linked TRAF6 ubiquitination and the promotion of K48-linked TRAF6 ubiquitination, inhibiting the activation of NF-κB and promoting the degradation of TRAF6. Moreover, TRAF6 knockdown countered Rnd3 knockout-evoked exacerbation of EC pyroptosis in vivo and vitro. These findings establish a critical functional connection between Rnd3 and the TRAF6/NF-κB/NLRP3 signaling pathway in ECs, indicating the essential role of Rnd3 in preventing pyroptosis of ECs.

CXCL8 Promotes Endothelial-to-Mesenchymal Transition of Endothelial Cells and Protects Cells from Erastin-Induced Ferroptosis via CXCR2-Mediated Activation of the NF-κB Signaling Pathway.

CXCL8-CXCR1/CXCR2 signaling pathways might form complex crosstalk among different cell types within the ovarian tumor microenvironment, thereby modulating the behaviors of different cells. This study aimed to investigate the expression pattern of CXCL8 in the ovarian tumor microenvironment and its impact on both endothelial-to-mesenchymal transition (EndMT) and ferroptosis of endothelial cells. The human monocytic cell line THP-1 and the human umbilical vein endothelial cell line PUMC-HUVEC-T1 were used to conduct in vitro studies. Erastin was used to induce ferroptosis. Results showed that tumor-associated macrophages are the major source of CXCL8 in the tumor microenvironment. CXCL8 treatment promoted the nucleus entrance of NF-κB p65 and p65 phosphorylation via CXCR2 in endothelial cells, suggesting activated NF-κB signaling. Via the NF-κB signaling pathway, CXCL8 enhanced TGF-β1-induced EndMT of PUMC-HUVEC-T1 cells and elevated their expression of SLC7A11 and GPX4. These trends were drastically weakened in groups with CXCR2 knockdown or SB225002 treatment. TPCA-1 reversed CXCL8-induced upregulation of SLC7A11 and GPX4. CXCL8 protected endothelial cells from erastin-induced ferroptosis. However, these protective effects were largely canceled when CXCR2 was knocked down. In summary, CXCL8 can activate the NF-κB signaling pathway in endothelial cells in a CXCR2-dependent manner. The CXCL8-CXCR2/NF-κB axis can enhance EndMT and activate SLC7A11 and GPX4 expression, protecting endothelial cells from ferroptosis.

Lenvatinib improves anti-PD-1 therapeutic efficacy by promoting vascular normalization via the NRP-1-PDGFRβ complex in hepatocellular carcinoma.

The limited response to immune checkpoint blockades (ICBs) in patients with hepatocellular carcinoma (HCC) highlights the urgent need for broadening the scope of current immunotherapy approaches. Lenvatinib has been shown a potential synergistic effect with ICBs. This study investigated the optimal method for combining these two therapeutic agents and the underlying mechanisms. The effect of lenvatinib at three different doses on promoting tissue perfusion and vascular normalization was evaluated in both immunodeficient and immunocompetent mouse models. The underlying mechanisms were investigated by analyzing the vascular morphology of endothelial cells and pericytes. The enhanced immune infiltration of optimal-dose lenvatinib and its synergistic effect of lenvatinib and anti-PD-1 antibody was further evaluated by flow cytometry and immunofluorescence imaging. There was an optimal dose that superiorly normalized tumor vasculature and increased immune cell infiltration in both immunodeficient and immunocompetent mouse models. An adequate concentration of lenvatinib strengthened the integrity of human umbilical vein endothelial cells by inducing the formation of the NRP-1-PDGFRβ complex and activating the Crkl-C3G-Rap1 signaling pathway in endothelial cells. Additionally, it promoted the interaction between endothelial cells and pericytes by inducing tyrosine-phosphorylation in pericytes. Furthermore, the combination of an optimal dose of lenvatinib and an anti-PD-1 antibody robustly suppressed tumor growth. Our study proposes a mechanism that explains how the optimal dose of lenvatinib induces vascular normalization and confirms its enhanced synergistic effect with ICBs.

Cobra venom P-III class metalloproteinase atrase A induces inflammatory response and cell apoptosis in endothelial cells via its metalloproteinase domain

Snake venom metalloproteinases (SVMPs), which are a critical component of viperid and crotalid venoms, play various important roles in the pathogenesis of snakebite envenomation. The SVMPs from elapid venoms are not well elucidated, as compared with those from viperid and crotalid venoms. Atrase A is a nonhemorrhagic P-III SVMP purified from Naja atra venom that possesses only weak fibrinogenolytic activity. In our prior study, we found that atrase A detached adherent cells from the substrate. In this work, we investigated further the effect and mechanism of atrase A on endothelial cells. Oxidative damage, inflammatory mediators, apoptosis, and activation of the NF-κB and MAPK signaling pathways were measured after HMEC-1 cells were exposed to atrase A. The results showed that HMEC-1 cells released inflammatory mediators, exihibited oxidative damage and apoptosis after exposure to atrase A. The Western blot analysis results revealed that atrase A increased Bax/Bcl-2 and caspase-3 levels and activated the NF-κB and MAPK signaling pathways in endothelial cells. The effects on endothelial cells were nearly completely abolished after atrase A was treated with ethylenediamine tetraacetic acid. These results showed that atrase A led to an inflammatory response, cellular injury and apoptosis in endothelial cells, and this effect was due to its metalloproteinase domain. The study contributes to a better understanding of the structures and functions of cobra venom P-III class metalloproteinases.

LKB1/STK11 Tumor Suppressor Reduces Angiogenesis by Directly Interacting with VEGFR2 in Tumorigenesis.

Cervical tumors represent a prevalent form of cancer affecting women worldwide; current treatment options involve surgery, radiotherapy, and chemotherapy. Angiogenesis, the process of new blood vessel formation, is a crucial factor in cervical tumor growth. The molecular mechanisms underlying the effects of the liver kinase B1 (LKB1/STK11) tumor suppressor protein on tumor angiogenesis have not been elucidated. Therefore, we investigated the role of LKB1 in cervical tumor angiogenesis both in vitro and in vivo in this study. Our results demonstrated that LKB1 inhibited cervical tumor angiogenesis by suppressing the expression of angiogenesis-related factors such as vascular endothelial growth factor (VEGF) and hypoxia inducible factor-1α. LKB1 directly affected both carcinoma and vascular endothelial cells, resulting in a significant reduction in tumor growth and angiogenesis. Furthermore, LKB1 was found to bind to VEGF receptor 2 (VEGFR-2) and target the VEGFR-2-mediated protein kinase B/mechanistic target of rapamycin signaling pathway in endothelial cells, thereby reducing cervical tumor growth and angiogenesis. Our study provides new insights into the molecular mechanisms underlying the anti-tumor and anti-angiogenic effects of LKB1 in cervical cancer. These findings will help develop new therapeutic strategies for cervical cancer.