Single cell analysis reveals the roles and regulatory mechanisms of type-I interferons in Parkinson's disease.

The pathogenesis of Parkinson's disease (PD) is strongly associated with neuroinflammation, and type I interferons (IFN-I) play a crucial role in regulating immune and inflammatory responses. However, the specific features of IFN in different cell types and the underlying mechanisms of PD have yet to be fully described. In this study, we analyzed the GSE157783 dataset, which includes 39,024 single-cell RNA sequencing results for five PD patients and six healthy controls from the Gene Expression Omnibus database. After cell type annotation, we intersected differentially expressed genes in each cell subcluster with genes collected in The Interferome database to generate an IFN-I-stimulated gene set (ISGs). Based on this gene set, we used the R package AUCell to score each cell, representing the IFN-I activity. Additionally, we performed monocle trajectory analysis, and single-cell regulatory network inference and clustering (SCENIC) to uncover the underlying mechanisms. In silico gene perturbation and subsequent experiments confirm NFATc2 regulation of type I interferon response and neuroinflammation. Our analysis revealed that microglia, endothelial cells, and pericytes exhibited the highest activity of IFN-I. Furthermore, single-cell trajectory detection demonstrated that microglia in the midbrain of PD patients were in a pro-inflammatory activation state, which was validated in the 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mouse model as well. We identified transcription factors NFATc2, which was significantly up-regulated and involved in the expression of ISGs and activation of microglia in PD. In the 1-Methyl-4-phenylpyridinium (MPP+)-induced BV2 cell model, the suppression of NFATc2 resulted in a reduction in IFN-ß levels, impeding the phosphorylation of STAT1, and attenuating the activation of the NF-κB pathway. Furthermore, the downregulation of NFATc2 mitigated the detrimental effects on SH-SY5Y cells co-cultured in conditioned medium. Our study highlights the critical role of microglia in type I interferon responses in PD. Additionally, we identified transcription factors NFATc2 as key regulators of aberrant type I interferon responses and microglial pro-inflammatory activation in PD. These findings provide new insights into the pathogenesis of PD and may have implications for the development of novel therapeutic strategies.

Overexpression of HSP27 accelerates stress-induced gastric ulcer healing via the CXCL12/CXCR4 axis.

Chronic stress often triggers gastrointestinal complications, including gastric injury and ulcers. Understanding the role of heat shock protein 27 (HSP27) in stress-induced gastric ulcers could unveil novel therapeutic targets. Here, we established a stress-induced gastric ulcer rat model using water immersion restraint stress and administered adenovirus-packaged HSP27 overexpression vector. Gastric ulcer severity was scored, and mucosal changes were assessed. Gastric epithelial and endothelial cells were treated with lipopolysaccharide and transfected with HSP27 overexpression vectors to evaluate cell viability, migration and angiogenesis. Expression levels of HSP27, C-X-C motif chemokine ligand 12 (CXCL12) and C-X-C motif chemokine receptor 4 (CXCR4) were measured in tissues and cells. HSP27 expression was initially low during stress-induced gastric ulceration but increased during ulcer healing. HSP27 overexpression accelerated ulcer healing in rats, promoting gastric epithelial cell proliferation and migration and gastric endothelial cell angiogenesis through the CXCL12/CXCR4 axis. Inhibitor IT1t reversed the effects of HSP27 overexpression on cell proliferation, migration and angiogenesis. In summary, HSP27 overexpression facilitated ulcer healing, which was partially mediated by the CXCL12/CXCR4 axis.

Lack of Laminar Shear Stress Facilitates the Endothelial Uptake of Very Small Superparamagnetic Iron Oxide Nanoparticles by Modulating the Endothelial Surface Layer.

Purpose: To study whether the absence of laminar shear stress (LSS) enables the uptake of very small superparamagnetic iron oxide nanoparticles (VSOP) in endothelial cells by altering the composition, size, and barrier function of the endothelial surface layer (ESL). Methods and Results: A quantitative particle exclusion assay with living human umbilical endothelial cells using spinning disc confocal microscopy revealed that the dimension of the ESL was reduced in cells cultivated in the absence of LSS. By combining gene expression analysis, flow cytometry, high pressure freezing/freeze substitution immuno-transmission electron microscopy, and confocal laser scanning microscopy, we investigated changes in ESL composition. We found that increased expression of the hyaluronan receptor CD44 by absence of shear stress did not affect the uptake rate of VSOPs. We identified collagen as a previously neglected component of ESL that contributes to its barrier function. Experiments with inhibitor halofuginone and small interfering RNA (siRNA) demonstrated that suppression of collagen expression facilitates VSOP uptake in endothelial cells grown under LSS. Conclusion: The absence of laminar shear stress disturbs the barrier function of the ESL, facilitating membrane accessibility and endocytic uptake of VSOP. Collagen, a previously neglected component of ESL, contributes to its barrier function.

RSAD2 is abundant in atherosclerotic plaques and promotes interferon-induced CXCR3-chemokines in human smooth muscle cells.

In atherosclerotic lesions, monocyte-derived macrophages are major source of interferon gamma (IFN-γ), a pleotropic cytokine known to regulate the expression of numerous genes, including the antiviral gene RSAD2. While RSAD2 was reported to be expressed in endothelial cells of human carotid lesions, its significance for the development of atherosclerosis remains utterly unknown. Here, we harnessed publicly available human carotid atherosclerotic data to explore RSAD2 in lesions and employed siRNA-mediated gene-knockdown to investigate its function in IFN-γ-stimulated human aortic smooth muscle cells (hAoSMCs). Silencing RSAD2 in IFN-γ-stimulated hAoSMCs resulted in reduced expression and secretion of key CXCR3-chemokines, CXCL9, CXCL10, and CXCL11. Conditioned medium from RSAD2-deficient hAoSMCs exhibited diminished monocyte attraction in vitro compared to conditioned medium from control cells. Furthermore, RSAD2 transcript was elevated in carotid lesions where it was expressed by several different cell types, including endothelial cells, macrophages and smooth muscle cells. Interestingly, RSAD2 displayed significant correlations with CXCL10 (r = 0.45, p = 0.010) and CXCL11 (r = 0.53, p = 0.002) in human carotid lesions. Combining our findings, we uncover a novel role for RSAD2 in hAoSMCs, which could potentially contribute to monocyte recruitment in the context of atherosclerosis.

Fasting upregulates the monocarboxylate transporter MCT1 at the rat blood-brain barrier through PPAR δ activation.

BACKGROUND: The blood-brain barrier (BBB) is pivotal for the maintenance of brain homeostasis and it strictly regulates the cerebral transport of a wide range of endogenous compounds and drugs. While fasting is increasingly recognized as a potential therapeutic intervention in neurology and psychiatry, its impact upon the BBB has not been studied. This study was designed to assess the global impact of fasting upon the repertoire of BBB transporters. METHODS: We used a combination of in vivo and in vitro experiments to assess the response of the brain endothelium in male rats that were fed ad libitum or fasted for one to three days. Brain endothelial cells were acutely purified and transcriptionaly profiled using RNA-Seq. Isolated brain microvessels were used to assess the protein expression of selected BBB transporters through western blot. The molecular mechanisms involved in the adaptation to fasting were investigated in primary cultured rat brain endothelial cells. MCT1 activity was probed by in situ brain perfusion. RESULTS: Fasting did not change the expression of the main drug efflux ATP-binding cassette transporters or P-glycoprotein activity at the BBB but modulated a restrictive set of solute carrier transporters. These included the ketone bodies transporter MCT1, which is pivotal for the brain adaptation to fasting. Our findings in vivo suggested that PPAR δ, a major lipid sensor, was selectively activated in brain endothelial cells in response to fasting. This was confirmed in vitro where pharmacological agonists and free fatty acids selectively activated PPAR δ, resulting in the upregulation of MCT1 expression. Moreover, dosing rats with a specific PPAR δ antagonist blocked the upregulation of MCT1 expression and activity induced by fasting. CONCLUSIONS: Altogether, our study shows that fasting affects a selected set of BBB transporters which does not include the main drug efflux transporters. Moreover, we describe a previously unknown selective adaptive response of the brain vasculature to fasting which involves PPAR δ and is responsible for the up-regulation of MCT1 expression and activity. Our study opens new perspectives for the metabolic manipulation of the BBB in the healthy or diseased brain.

SARS-CoV-2 causes dysfunction in human iPSC-derived brain microvascular endothelial cells potentially by modulating the Wnt signaling pathway.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19), which is associated with various neurological symptoms, including nausea, dizziness, headache, encephalitis, and epileptic seizures. SARS-CoV-2 is considered to affect the central nervous system (CNS) by interacting with the blood-brain barrier (BBB), which is defined by tight junctions that seal paracellular gaps between brain microvascular endothelial cells (BMECs). Although SARS-CoV-2 infection of BMECs has been reported, the detailed mechanism has not been fully elucidated. METHODS: Using the original strain of SARS-CoV-2, the infection in BMECs was confirmed by a detection of intracellular RNA copy number and localization of viral particles. BMEC functions were evaluated by measuring transendothelial electrical resistance (TEER), which evaluates the integrity of tight junction dynamics, and expression levels of proinflammatory genes. BMEC signaling pathway was examined by comprehensive RNA-seq analysis. RESULTS: We observed that iPSC derived brain microvascular endothelial like cells (iPSC-BMELCs) were infected with SARS-CoV-2. SARS-CoV-2 infection resulted in decreased TEER. In addition, SARS-CoV-2 infection decreased expression levels of tight junction markers CLDN3 and CLDN11. SARS-CoV-2 infection also increased expression levels of proinflammatory genes, which are known to be elevated in patients with COVID-19. Furthermore, RNA-seq analysis revealed that SARS-CoV-2 dysregulated the canonical Wnt signaling pathway in iPSC-BMELCs. Modulation of the Wnt signaling by CHIR99021 partially inhibited the infection and the subsequent inflammatory responses. CONCLUSION: These findings suggest that SARS-CoV-2 infection causes BBB dysfunction via Wnt signaling. Thus, iPSC-BMELCs are a useful in vitro model for elucidating COVID-19 neuropathology and drug development.

Single-cell 'omic profiles of human aortic endothelial cells in vitro and human atherosclerotic lesions ex vivo reveal heterogeneity of endothelial subtype and response to activating perturbations.

Heterogeneity in endothelial cell (EC) sub-phenotypes is becoming increasingly appreciated in atherosclerosis progression. Still, studies quantifying EC heterogeneity across whole transcriptomes and epigenomes in both in vitro and in vivo models are lacking. Multiomic profiling concurrently measuring transcriptomes and accessible chromatin in the same single cells was performed on six distinct primary cultures of human aortic ECs (HAECs) exposed to activating environments characteristic of the atherosclerotic microenvironment in vitro. Meta-analysis of single-cell transcriptomes across 17 human ex vivo arterial specimens was performed and two computational approaches quantitatively evaluated the similarity in molecular profiles between heterogeneous in vitro and ex vivo cell profiles. HAEC cultures were reproducibly populated by four major clusters with distinct pathway enrichment profiles and modest heterogeneous responses: EC1-angiogenic, EC2-proliferative, EC3-activated/mesenchymal-like, and EC4-mesenchymal. Quantitative comparisons between in vitro and ex vivo transcriptomes confirmed EC1 and EC2 as most canonically EC-like, and EC4 as most mesenchymal with minimal effects elicited by siERG and IL1B. Lastly, accessible chromatin regions unique to EC2 and EC4 were most enriched for coronary artery disease (CAD)-associated single-nucleotide polymorphisms from Genome Wide Association Studies (GWAS), suggesting that these cell phenotypes harbor CAD-modulating mechanisms. Primary EC cultures contain markedly heterogeneous cell subtypes defined by their molecular profiles. Surprisingly, the perturbations used here only modestly shifted cells between subpopulations, suggesting relatively stable molecular phenotypes in culture. Identifying consistently heterogeneous EC subpopulations between in vitro and ex vivo models should pave the way for improving in vitro systems while enabling the mechanisms governing heterogeneous cell state decisions.

Statins improve cardiac endothelial function to prevent heart failure with preserved ejection fraction through upregulating circRNA-RBCK1.

Heart failure with preserved ejection fraction (HFpEF) is associated with endothelial dysfunction. We have previously reported that statins prevent endothelial dysfunction through inhibition of microRNA-133a (miR-133a). This study is to investigate the effects and the underlying mechanisms of statins on HFpEF. Here, we show that statins upregulate the expression of a circular RNA (circRNA-RBCK1) which is co-transcripted with the ring-B-box-coiled-coil protein interacting with protein kinase C-1 (RBCK1) gene. Simultaneously, statins increase activator protein 2 alpha (AP-2α) transcriptional activity and the interaction between circRNA-RBCK1 and miR-133a. Furthermore, AP-2α directly interacts with RBCK1 gene promoter in endothelial cells. In vivo, lovastatin improves diastolic function in male mice under HFpEF, which is abolished by loss function of endothelial AP-2α or circRNA-RBCK1. This study suggests that statins upregulate the AP-2α/circRNA-RBCK1 signaling to suppress miR-133a in cardiac endothelial cells and prevent diastolic dysfunction in HFpEF.

Toll-like receptor 4 in pancreatic damage and immune infiltration in acute pancreatitis.

Acute pancreatitis is a complex inflammatory disease resulting in extreme pain and can result in significant morbidity and mortality. It can be caused by several factors ranging from genetics, alcohol use, gall stones, and ductal obstruction caused by calcification or neutrophil extracellular traps. Acute pancreatitis is also characterized by immune cell infiltration of neutrophils and M1 macrophages. Toll-like receptor 4 (TLR4) is a pattern recognition receptor that has been noted to respond to endogenous ligands such as high mobility group box 1 (HMGB1) protein and or exogenous ligands such as lipopolysaccharide both of which can be present during the progression of acute pancreatitis. This receptor can be found on a variety of cell types from endothelial cells to resident and infiltrating immune cells leading to production of pro-inflammatory cytokines as well as immune cell activation and maturation resulting in the furthering of pancreatic damage during acute pancreatitis. In this review we will address the various mechanisms mediated by TLR4 in the advancement of acute pancreatitis and how targeting this receptor could lead to improved outcomes for patients suffering from this condition.

The high-density lipoprotein cholesterol (HDL-C)-concentration-dependent association between anti-inflammatory capacity and sepsis: A single-center cross-sectional study.

INTRODUCTION: Known to have pleiotropic functions, high-density lipoprotein (HDL) helps to regulate systemic inflammation during sepsis. As preserving HDL-C level is a promising therapeutic strategy for sepsis, the interaction between HDL and sepsis worth further investigation. This study aimed to determine the impact of sepsis on HDL's anti-inflammatory capacity and explore its correlations with disease severity and laboratory parameters. METHODS AND MATERIALS: We enrolled 80 septic subjects admitted to the intensive care unit and 50 controls admitted for scheduled coronary angiography in this cross-sectional study. We used apolipoprotein-B depleted (apoB-depleted) plasma to measure the anti-inflammatory capacity of HDL-C. ApoB-depleted plasma's anti-inflammatory capacity is defined as its ability to suppress tumor necrosis factor-α-induced vascular cell adhesion molecule-1 (VCAM-1) expression in human umbilical-vein endothelial cells. A subgroup analysis was conducted to investigate in septic subjects according to disease severity. RESULTS: ApoB-depleted plasma's anti-inflammatory capacity was reduced in septic subjects relative to controls (VCAM-1 mRNA fold change: 50.1% vs. 35.5%; p < 0.0001). The impairment was more pronounced in septic subjects with than in those without septic shock (55.8% vs. 45.3%, p = 0.0022). Both associations were rendered non-significant with the adjustment for the HDL-C level. In sepsis patients, VCAM-1 mRNA fold change correlated with the SOFA score (Spearman's r = 0.231, p = 0.039), lactate level (r = 0.297, p = 0.0074), HDL-C level (r = -0.370, p = 0.0007), and inflammatory markers (C-reactive protein level: r = 0.441, p <0.0001; white blood cell: r = 0.353, p = 0.0013). CONCLUSION: ApoB-depleted plasma's anti-inflammatory capacity is reduced in sepsis patients and this association depends of HDL-C concentration. In sepsis patients, this capacity correlates with disease severity and inflammatory markers. These findings explain the prognostic role of the HDL-C level in sepsis and indirectly support the rationale for targeting HDL-C as sepsis treatment.

[Dynamic observation on capillarization of liver sinusoidal endothelial cells induced by Echinococcus multilocularis infection].

OBJECTIVE: To investigate the capillarization of liver sinusoidal endothelial cells (LSECs) and its association with hepatic fibrosis during the development of alveolar echinococcosis, so as to provide the basis for unraveling the mechanisms underlying the role of LSEC in the development and prognosis of hepatic injuries and hepatic fibrosis caused by alveolar echinococcosis. METHODS: Forty C57BL/6 mice at ages of 6 to 8 weeks were randomly divided into a control group and 1-, 2- and 4-week infection groups, of 10 mice in each group. Each mouse in the infection groups was intraperitoneally injected with 2 000 Echinococcus multilocularis protoscoleces, while each mouse in the control group was given an equal volume of phosphate-buffered saline using the same method. All mice were sacrificed 1, 2 and 4 weeks post-infection and mouse livers were collected. The pathological changes of livers were observed using hematoxylin-eosin (HE) staining, and hepatic fibrosis was evaluated through semi-quantitative analysis of Masson's trichrome staining-positive areas. The activation of hepatic stellate cells (HSCs) and extracellular matrix (ECM) deposition were examined using immunohistochemical staining of α-smooth muscle actin (α-SMA) and collagen type I alpha 1 (COL1A1), and the fenestrations on the surface of LSECs were observed using scanning electron microscopy. Primary LSECs were isolated from mouse livers, and the mRNA expression of LSEC marker genes Stabilin-1, Stabilin-2, Ehd3, CD209b, GATA4 and Maf was quantified using real-time fluorescence quantitative PCR (qPCR) assay. RESULTS: Destruction of local liver lobular structure was observed in mice 2 weeks post-infection with E. multilocularis protoscoleces, and hydatid cysts, which were surrounded by granulomatous tissues, were found in mouse livers 4 weeks post-infection. Semi-quantitative analysis of Masson's trichrome staining showed a significant difference in the proportion of collagen fiber contents in mouse livers among the four groups (F = 26.060, P < 0.001), and a higher proportion of collagen fiber contents was detected in mouse livers in the 4-week infection group [(11.29 ± 2.58)%] than in the control group (P < 0.001). Immunohistochemical staining revealed activation of a few HSCs and ECM deposition in mouse livers 1 and 2 weeks post-infection, and abundant brown-yellow stained α-SMA and COL1A1 were deposited in the lesion areas in mouse livers 4 weeks post-infection, which spread to surrounding tissues. Semi-quantitative analysis revealed significant differences in α-SMA (F = 7.667, P < 0.05) and COL1A1 expression (F = 6.530, P < 0.05) in mouse levers among the four groups, with higher α-SMA [(7.13 ± 3.68)%] and COL1A1 expression [(13.18 ± 7.20)%] quantified in mouse livers in the 4-week infection group than in the control group (both P values < 0.05). Scanning electron microscopy revealed significant differences in the fenestration frequency (F = 37.730, P < 0.001) and porosity (F = 16.010, P < 0.001) on the surface of mouse LSECs among the four groups, and reduced fenestration frequency and porosity were observed in the 1-[(1.22 ± 0.48)/µm2 and [(3.05 ± 0.91)%] and 2-week infection groups [(3.47 ± 0.10)/µm2 and (7.57 ± 0.23)%] groups than in the control group (all P values < 0.001). There was a significant difference in the average fenestration diameter on the surface of mouse LSECs among the four groups (F = 15.330, P < 0.001), and larger average fenestration diameters were measured in the 1-[(180.80 ± 16.42) nm] and 2-week infection groups [(161.70 ± 3.85) nm] than in the control group (both P values < 0.05). In addition, there were significant differences among the four groups in terms of Stabilin-1 (F = 153.100, P < 0.001), Stabilin-2 (F = 57.010, P < 0.001), Ehd3 (F = 31.700, P < 0.001), CD209b (F = 177.400, P < 0.001), GATA4 (F = 17.740, P < 0.001), and Maf mRNA expression (F = 72.710, P < 0.001), and reduced mRNA expression of Stabilin-1, Stabilin-2, Ehd3, CD209b, GATA4 and Maf genes was quantified in three infection groups than in the control group (all P values < 0.001). CONCLUSIONS: E. multilocularis infections may induce capillarization of LSECs in mice, and result in a reduction in the expression of functional and phenotypic marker genes of LSECs, and capillarization of LSECs occurs earlier than activation of HSC and development of hepatic fibrosis.

Disulfiram Reduces Atherosclerosis and Enhances Efferocytosis, Autophagy, and Atheroprotective Gut Microbiota in Hyperlipidemic Mice.

BACKGROUND: Pyroptosis executor GsdmD (gasdermin D) promotes atherosclerosis in mice and humans. Disulfiram was recently shown to potently inhibit GsdmD, but the in vivo efficacy and mechanism of disulfiram's antiatherosclerotic activity is yet to be explored. METHODS AND RESULTS: We used human/mouse macrophages, endothelial cells, and smooth muscle cells and a hyperlipidemic mouse model of atherosclerosis to determine disulfiram antiatherosclerotic efficacy and mechanism. The effects of disulfiram on several atheroprotective pathways such as autophagy, efferocytosis, phagocytosis, and gut microbiota were determined. Atomic force microscopy was used to determine the effects of disulfiram on the biophysical properties of the plasma membrane of macrophages. Disulfiram-fed hyperlipidemic apolipoprotein E-/- mice showed significantly reduced interleukin-1ß release upon in vivo Nlrp3 (NLR family pyrin domain containing 3) inflammasome activation. Disulfiram-fed mice showed smaller atherosclerotic lesions (~27% and 29% reduction in males and females, respectively) and necrotic core areas (~50% and 46% reduction in males and females, respectively). Disulfiram induced autophagy in macrophages, smooth muscle cells, endothelial cells, hepatocytes/liver, and atherosclerotic plaques. Disulfiram modulated other atheroprotective pathways (eg, efferocytosis, phagocytosis) and gut microbiota. Disulfiram-treated macrophages showed enhanced phagocytosis/efferocytosis, with the mechanism being a marked increase in cell-surface expression of efferocytic receptor MerTK. Atomic force microscopy analysis revealed altered biophysical properties of disulfiram-treated macrophages, showing increased order-state of plasma membrane and increased adhesion strength. Furthermore, 16sRNA sequencing of disulfiram-fed hyperlipidemic mice showed highly significant enrichment in atheroprotective gut microbiota Akkermansia and a reduction in atherogenic Romboutsia species. CONCLUSIONS: Taken together, our data show that disulfiram can simultaneously modulate several atheroprotective pathways in a GsdmD-dependent as well as GsdmD-independent manner.

[Mechanism of astragaloside â £ combined with Panax notoginseng saponins in regulating angiogenesis to treat cerebral ischemia based on network pharmacology and experimental verification].

Network pharmacology and animal and cell experiments were employed to explore the mechanism of astragaloside Ⅳ(AST Ⅳ) combined with Panax notoginseng saponins(PNS) in regulating angiogenesis to treat cerebral ischemia. The method of network pharmacology was used to predict the possible mechanisms of AST Ⅳ and PNS in treating cerebral ischemia by mediating angiogenesis. In vivo experiment: SD rats were randomized into sham, model, and AST Ⅳ(10 mg·kg~(-1)) + PNS(25 mg·kg~(-1)) groups, and the model of cerebral ischemia was established with middle cerebral artery occlusion(MCAO) method. AST Ⅳ and PNS were administered by gavage twice a day. the Longa method was employed to measure the neurological deficits. The brain tissue was stained with hematoxylin-eosin(HE) to reveal the pathological damage. Immunohistochemical assay was employed to measure the expression of von Willebrand factor(vWF), and immunofluorescence assay to measure the expression of vascular endothelial growth factor A(VEGFA). Western blot was employed to determine the protein levels of vascular endothelial growth factor receptor 2(VEGFR2), VEGFA, phosphorylated phosphatidylinositol 3-kinase(p-PI3K), and phosphorylated protein kinase B(p-AKT) in the brain tissue. In vitro experiment: the primary generation of rat brain microvascular endothelial cells(rBEMCs) was cultured and identified. The third-generation rBMECs were assigned into control, model, AST Ⅳ(50 µmol·L~(-1)) + PNS(30 µmol·L~(-1)), LY294002(PI3K/AKT signaling pathway inhibitor), 740Y-P(PI3K/AKT signaling pathway agonist), AST Ⅳ + PNS + LY294002, and AST Ⅳ + PNS + 740Y-P groups. Oxygen glucose deprivation/re-oxygenation(OGD/R) was employed to establish the cell model of cerebral ischemia-reperfusion injury. The cell counting kit-8(CCK-8) and scratch assay were employed to examine the survival and migration of rBEMCs, respectively. Matrigel was used to evaluate the tube formation from rBEMCs. The Transwell assay was employed to examine endothelial cell permeability. Western blot was employed to determine the expression of VEGFR2, VEGFA, p-PI3K, and p-AKT in rBEMCs. The results of network pharmacology analysis showed that AST Ⅳ and PNS regulated 21 targets including VEGFA and AKT1 of angiogenesis in cerebral infarction. Most of these 21 targets were involved in the PI3K/AKT signaling pathway. The in vivo experiments showed that compared with the model group, AST Ⅳ + PNS reduced the neurological deficit score(P<0.05) and the cell damage rate in the brain tissue(P<0.05), promoted the expression of vWF and VEGFA(P<0.01) and angiogenesis, and up-regulated the expression of proteins in the PI3K/AKT pathway(P<0.05, P<0.01). The in vitro experiments showed that compared with the model group, the AST Ⅳ + PNS, 740Y-P, AST Ⅳ + PNS + LY294002, and AST Ⅳ + PNS + 740Y-P improved the survival of rBEMCs after OGD/R, enhanced the migration of rBEMCs, increased the tubes formed by rBEMCs, up-regulated the expression of proteins in the PI3K/AKT pathway, and reduced endothelial cell permeability(P<0.05, P<0.01). Compared with the LY294002 group, the AST Ⅳ + PNS + LY294002 group showed increased survival rate, migration rate, and number of tubes, up-regulated expression of proteins in the PI3K/AKT pathway, and decreased endothelial cell permeability(P<0.05,P<0.01). Compared with the AST Ⅳ + PNS and 740Y-P groups, the AST Ⅳ + PNS + 740Y-P group presented increased survival rate, migration rate, and number of tubes and up-regulated expression of proteins in the PI3K/AKT pathway, and reduced endothelial cell permeability(P<0.01). This study indicates that AST Ⅳ and PNS can promote angiogenesis after cerebral ischemia by activating the PI3K/AKT signaling pathway.

An arresten-derived anti-angiogenic peptide triggers apoptotic cell death in endothelial cells.

BACKGROUND: In recent years, anti-angiogenic peptides have received considerable attention as candidates for cancer treatment. Arresten is an angiogenesis inhibitor that cleaves from the α1 chain of type IV collagen and stimulates apoptosis in endothelial cells. We have recently indicated that a peptide corresponding to the amino acid 78 to 86 of arresten, so-called Ars, prevented the migration and tube formation of HUVECs and the colon carcinoma growth in mice significantly. The current study aimed to determine whether induction of apoptotic cell death in endothelial cells is one of the biochemical mechanisms of this anti-angiogenic peptide. METHODS AND RESULTS: This hypothesis was assessed using the MTT assay, cell cycle analysis, Annexin V-FITC/PI staining, BCL2, CASP8, CASP9, p53, and CDKN2A gene expression studies as well as evaluating apoptosis in tumor tissues by TUNEL assay. Results demonstrated that 40 µM of Ars significantly stimulated 46.2% of early and late apoptosis in HUVECs compared to 13.6% in the untreated cells and did not significantly alter the cell cycle distribution. Moreover, BCL2 and CASP8 were down-regulated, while CASP9 and p53 were up-regulated in endothelial cells. CDKN2A gene expression, the regulator of G1 cell cycle arrest, was not significantly altered. CONCLUSIONS: It might be suggested that Ars induced apoptosis in endothelial cells through the mitochondrial pathway and had no effect on the cell cycle. Besides, Ars induced apoptosis significantly in vivo. However, further studies are required to confirm the detailed molecular mechanism of Ars, this peptide has the potential to be optimized for clinical translations.

Endothelial Mitochondria-Associated Membranes (MAMs) Isolation by Percoll Step Gradients.

Mitochondria-associated membranes (MAMs) are regions where the endoplasmic reticulum (ER) interacts with mitochondria and regulate lipid trafficking, calcium signaling, ER stress, and inflammation activation. Isolation of MAMs from endothelial cells is vital for studying insight into the immune regulation of many inflammatory diseases. Endothelial cells (ECs) are critical innate immune cells due to their paracrine function of secreting interleukins, chemokines, cytokines, and growth factors, as well as expressing levels of pattern recognition receptors including toll-like receptors (TLRs). Furthermore, ECs regulate and recruit monocytes by expressing adhesion molecules including vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), P-selectin, and E-selectin, to facilitate monocyte diapedesis in areas of damage and inflammation. This protocol consists of step-by-step instructions on isolating pure MAMs and other subcellular fractions from endothelial cells, which is critical to understanding ER and mitochondria crosstalks in endothelial functions in health and disease.

Salvianic acid A sodium facilitates cardiac microvascular endothelial cell proliferation by enhancing the hypoxia-inducible factor-1 alpha/vascular endothelial growth factor signalling pathway post-myocardial infarction.

Cardiac microvascular endothelial cells (CMECs) are important cells surrounding the cardiomyocytes in the heart that maintain microenvironment homeostasis. Salvianic acid A sodium (SAAS) has been reported to prevent myocardial infarction (MI) injury. However, the role of SAAS on CMEC proliferation remains unclear. CEMCs exposed to oxygen glucose deprivation (OGD) were used to explore the angiogenic abilities of SAAS. In vivo, C57BL/6 mice were divided into three groups: sham, MI and SAAS + MI groups. Compared to OGD group, SAAS led to a reduction in the apoptotic rate and an increase of the proliferation in vitro. Additionally, SAAS increased the protein levels of Bcl2, HIF-1α and vascular endothelial growth factor (VEGF) with the reduction of Bax. In terms of the specific mechanisms, SAAS might inhibit HIF-1α ubiquitination and enhance the HIF-1α/VEGF signalling pathway to increase CMEC proliferation. Furthermore, SAAS increased the density of vessels, inhibited myocardial fibrosis and improved cardiac dysfunction in vivo. The present study has revealed that SAAS could potentially be used as an active substance to facilitate CMEC proliferation post-MI.

Spatial transcriptomics reveals discrete tumour microenvironments and autocrine loops within ovarian cancer subclones.

High-grade serous ovarian carcinoma (HGSOC) is genetically unstable and characterised by the presence of subclones with distinct genotypes. Intratumoural heterogeneity is linked to recurrence, chemotherapy resistance, and poor prognosis. Here, we use spatial transcriptomics to identify HGSOC subclones and study their association with infiltrating cell populations. Visium spatial transcriptomics reveals multiple tumour subclones with different copy number alterations present within individual tumour sections. These subclones differentially express various ligands and receptors and are predicted to differentially associate with different stromal and immune cell populations. In one sample, CosMx single molecule imaging reveals subclones differentially associating with immune cell populations, fibroblasts, and endothelial cells. Cell-to-cell communication analysis identifies subclone-specific signalling to stromal and immune cells and multiple subclone-specific autocrine loops. Our study highlights the high degree of subclonal heterogeneity in HGSOC and suggests that subclone-specific ligand and receptor expression patterns likely modulate how HGSOC cells interact with their local microenvironment.

Mesenchymal glioma stem cells trigger vasectasia-distinct neovascularization process stimulated by extracellular vesicles carrying EGFR.

Targeting neovascularization in glioblastoma (GBM) is hampered by poor understanding of the underlying mechanisms and unclear linkages to tumour molecular landscapes. Here we report that different molecular subtypes of human glioma stem cells (GSC) trigger distinct endothelial responses involving either angiogenic or circumferential vascular growth (vasectasia). The latter process is selectively triggered by mesenchymal (but not proneural) GSCs and is mediated by a subset of extracellular vesicles (EVs) able to transfer EGFR/EGFRvIII transcript to endothelial cells. Inhibition of the expression and phosphorylation of EGFR in endothelial cells, either pharmacologically (Dacomitinib) or genetically (gene editing), abolishes their EV responses in vitro and disrupts vasectasia in vivo. Therapeutic inhibition of EGFR markedly extends anticancer effects of VEGF blockade in mice, coupled with abrogation of vasectasia and prolonged survival. Thus, vasectasia driven by intercellular transfer of oncogenic EGFR may represent a new therapeutic target in a subset of GBMs.

Eph-ephrin signaling couples endothelial cell sorting and arterial specification.

Cell segregation allows the compartmentalization of cells with similar fates during morphogenesis, which can be enhanced by cell fate plasticity in response to local molecular and biomechanical cues. Endothelial tip cells in the growing retina, which lead vessel sprouts, give rise to arterial endothelial cells and thereby mediate arterial growth. Here, we have combined cell type-specific and inducible mouse genetics, flow experiments in vitro, single-cell RNA sequencing and biochemistry to show that the balance between ephrin-B2 and its receptor EphB4 is critical for arterial specification, cell sorting and arteriovenous patterning. At the molecular level, elevated ephrin-B2 function after loss of EphB4 enhances signaling responses by the Notch pathway, VEGF and the transcription factor Dach1, which is influenced by endothelial shear stress. Our findings reveal how Eph-ephrin interactions integrate cell segregation and arteriovenous specification in the vasculature, which has potential relevance for human vascular malformations caused by EPHB4 mutations.

The novel molecular mechanism of pulmonary fibrosis: insight into lipid metabolism from reanalysis of single-cell RNA-seq databases.

Pulmonary fibrosis (PF) is a severe pulmonary disease with limited available therapeutic choices. Recent evidence increasingly points to abnormal lipid metabolism as a critical factor in PF pathogenesis. Our latest research identifies the dysregulation of low-density lipoprotein (LDL) is a new risk factor for PF, contributing to alveolar epithelial and endothelial cell damage, and fibroblast activation. In this study, we first integrative summarize the published literature about lipid metabolite changes found in PF, including phospholipids, glycolipids, steroids, fatty acids, triglycerides, and lipoproteins. We then reanalyze two single-cell RNA-sequencing (scRNA-seq) datasets of PF, and the corresponding lipid metabolomic genes responsible for these lipids' biosynthesis, catabolism, transport, and modification processes are uncovered. Intriguingly, we found that macrophage is the most active cell type in lipid metabolism, with almost all lipid metabolic genes being altered in macrophages of PF. In type 2 alveolar epithelial cells, lipid metabolic differentially expressed genes (DEGs) are primarily associated with the cytidine diphosphate diacylglycerol pathway, cholesterol metabolism, and triglyceride synthesis. Endothelial cells are partly responsible for sphingomyelin, phosphatidylcholine, and phosphatidylethanolamines reprogramming as their metabolic genes are dysregulated in PF. Fibroblasts may contribute to abnormal cholesterol, phosphatidylcholine, and phosphatidylethanolamine metabolism in PF. Therefore, the reprogrammed lipid profiles in PF may be attributed to the aberrant expression of lipid metabolic genes in different cell types. Taken together, these insights underscore the potential of targeting lipid metabolism in developing innovative therapeutic strategies, potentially leading to extended overall survival in individuals affected by PF.