ICAM-1 Expression In Endothelial Cells Research Articles

Modeling lung endothelial dysfunction in sepsis-associated ARDS using a microphysiological system.

Endothelial dysfunction is a critical feature of acute respiratory distress syndrome (ARDS) associated with higher disease severity and worse outcomes. Preclinical invivo models of sepsis and ARDS have failed to yield useful therapies in humans, perhaps due to interspecies differences in inflammatory responses and heterogeneity of human host responses. Use of microphysiological systems (MPS) to investigate lung endothelial function may shed light on underlying mechanisms and targeted treatments for ARDS. We assessed the response to plasma from critically ill sepsis patients in our lung endothelial MPS through measurement of endothelial permeability, expression of adhesion molecules, and inflammatory cytokine secretion. Sepsis plasma induced areas of endothelial cell (EC) contraction, loss of cellular coverage, and luminal defects. EC barrier function was significantly worse following incubation with sepsis plasma compared to healthy plasma. EC ICAM-1 expression, IL-6 and soluble ICAM-1 secretion increased significantly more after incubation with sepsis plasma compared with healthy plasma. Plasma from sepsis patients who developed ARDS further increased IL-6 and sICAM-1 compared to plasma from sepsis patients without ARDS and healthy plasma. Our results demonstrate the proof of concept that lung endothelial MPS can enable interrogation of specific mechanisms of endothelial dysfunction that promote ARDS in sepsis patients.

Modeling lung endothelial dysfunction in sepsis-associated ARDS using a microphysiological system.

Endothelial dysfunction is a critical feature of acute respiratory distress syndrome (ARDS) associated with higher disease severity and worse outcomes. Preclinical invivo models of sepsis and ARDS have failed to yield useful therapies in humans, perhaps due to interspecies differences in inflammatory responses and heterogeneity of human host responses. Use of microphysiological systems (MPS) to investigate lung endothelial function may shed light on underlying mechanisms and targeted treatments for ARDS. We assessed the response to plasma from critically ill sepsis patients in our lung endothelial MPS through measurement of endothelial permeability, expression of adhesion molecules, and inflammatory cytokine secretion. Sepsis plasma induced areas of endothelial cell (EC) contraction, loss of cellular coverage, and luminal defects. EC barrier function was significantly worse following incubation with sepsis plasma compared to healthy plasma. EC ICAM-1 expression, IL-6 and soluble ICAM-1 secretion increased significantly more after incubation with sepsis plasma compared with healthy plasma. Plasma from sepsis patients who developed ARDS further increased IL-6 and sICAM-1 compared to plasma from sepsis patients without ARDS and healthy plasma. Our results demonstrate the proof of concept that lung endothelial MPS can enable interrogation of specific mechanisms of endothelial dysfunction that promote ARDS in sepsis patients.

ANGPTL3 is a novel HDL component that regulates HDL function

BackgroundAngiopoietin-like protein 3 (ANGPTL3) is secreted by hepatocytes and inhibits lipoprotein lipase and endothelial lipase activity. Previous studies reported the correlation between plasma ANGPTL3 levels and high-density lipoprotein (HDL). Recently ANGPTL3 was found to preferentially bind to HDL in healthy human circulation. Here, we examined whether ANGPTL3, as a component of HDL, modulates HDL function and affects HDL other components in human and mice with non-diabetes or type 2 diabetes mellitus.MethodsHDL was isolated from the plasma of female non-diabetic subjects and type-2 diabetic mellitus (T2DM) patients. Immunoprecipitation, western blot, and ELISA assays were used to examine ANGPTL3 levels in HDL. Db/m and db/db mice, AAV virus mediated ANGPTL3 overexpression and knockdown models and ANGPTL3 knockout mice were used. The cholesterol efflux capacity induced by HDL was analyzed in macrophages preloaded with fluorescent cholesterol. The anti-inflammation capacity of HDL was assessed using flow cytometry to measure VCAM-1 and ICAM-1 expression levels in TNF-α-stimulated endothelial cells pretreated with HDL.ResultsANGPTL3 was found to bind to HDL and be a component of HDL in both non-diabetic subjects and T2DM patients. Flag-ANGPTL3 was found in the HDL of transgenic mice overexpressing Flag-ANGPTL3. ANGPLT3 of HDL was positively associated with cholesterol efflux in female non-diabetic controls (r = 0.4102, p = 0.0117) but not in female T2DM patients (r = − 0.1725, p = 0.3224). Lower ANGPTL3 levels of HDL were found in diabetic (db/db) mice compared to control (db/m) mice and were associated with reduced cholesterol efflux and inhibition of VCAM-1 and ICAM-1 expression in endothelial cells (p < 0.05 for all). Following AAV-mediated ANGPTL3 cDNA transfer in db/db mice, ANGPTL3 levels were found to be increased in HDL, and corresponded to increased cholesterol efflux and decreased ICAM-1 expression. In contrast, knockdown of ANGPTL3 levels in HDL by AAV-mediated shRNA transfer led to a reduction in HDL function (p < 0.05 for both). Plasma total cholesterol, total triglycerides, HDL-c, protein components of HDL and the cholesterol efflux function of HDL were lower in ANGPTL3−/− mice than ANGPTL3+/+ mice, suggesting that ANGPTL3 in HDL may regulate HDL function by disrupting the balance of protein components in HDL.ConclusionANGPTL3 was identified as a component of HDL in humans and mice. ANGPTL3 of HDL regulated cholesterol efflux and the anti-inflammatory functions of HDL in T2DM mice. Both the protein components of HDL and cholesterol efflux capacity of HDL were decreased in ANGPTL3−/− mice. Our findings suggest that ANGPTL3 in HDL may regulate HDL function by disrupting the balance of protein components in HDL. Our study contributes to a more comprehensive understanding of the role of ANGPTL3 in lipid metabolism.

Platelet and endothelial cell responses under concurrent shear stress and tensile strain

Thrombosis can lead to significant mortality and morbidity. Both platelets and vascular endothelial cells play significant roles in thrombosis. Platelets' response to blood flow-induced shear stress can vary greatly depending on shear stress magnitude, pattern and shear exposure time. Endothelial cells are also sensitive to the biomechanical environment. Endothelial cell activation and dysfunction can occur under low oscillatory shear stress and low tensile strain. Platelet and endothelial cell interaction can also be affected by mechanical conditions. The goal of this study was to investigate how blood flow-induced shear stress, vascular wall tensile strain, platelet-endothelial cell stress history, and platelet-endothelial cell interaction affect platelet thrombogenicity. Platelets and human coronary artery endothelial cells were pretreated with physiological and pathological shear stress and/or tensile strain separately. The pretreated cells were then put together and exposed to pulsatile shear stress and cyclic tensile strain simultaneously in a shearing-stretching device. Following treatment, platelet thrombin generation rate, platelet and endothelial cell activation, and platelet adhesion to endothelial cells was measured. The results demonstrated that shear stress pretreatment of endothelial cells and platelets caused a significant increase in platelet thrombin generation rate, cell surface phosphatidylserine expression, and adhesion to endothelial cells. Shear stress pretreatment of platelets and endothelial cells attenuated endothelial cell ICAM-1 expression under stenosis conditions, as well as vWF expression under recirculation conditions. These results indicate that platelets are sensitized by prior shearing, while in comparison, the interaction with shear stress-pretreated platelets may reduce endothelial cell sensitivity to pathological shear stress and tensile strain.

The Polyanionic Drug Suramin Neutralizes Histones and Prevents Endotheliopathy.

Drugs are needed to protect against the neutrophil-derived histones responsible for endothelial injury in acute inflammatory conditions such as trauma and sepsis. Heparin and other polyanions can neutralize histones but challenges with dosing or side effects such as bleeding limit clinical application. In this study, we demonstrate that suramin, a widely available polyanionic drug, completely neutralizes the toxic effects of individual histones, but not citrullinated histones from neutrophil extracellular traps. The sulfate groups on suramin form stable electrostatic interactions with hydrogen bonds in the histone octamer with a dissociation constant of 250 nM. In cultured endothelial cells (Ea.Hy926), histone-induced thrombin generation was significantly decreased by suramin. In isolated murine blood vessels, suramin abolished aberrant endothelial cell calcium signals and rescued impaired endothelial-dependent vasodilation caused by histones. Suramin significantly decreased pulmonary endothelial cell ICAM-1 expression and neutrophil recruitment caused by infusion of sublethal doses of histones invivo. Suramin also prevented histone-induced lung endothelial cell cytotoxicity invitro and lung edema, intra-alveolar hemorrhage, and mortality in mice receiving a lethal dose of histones. Protection of vascular endothelial function from histone-induced damage is a novel mechanism of action for suramin with therapeutic implications for conditions characterized by elevated histone levels.

Soluble guanylate cyclase stimulator praliciguat promotes ischemic leg reperfusion in db/db mice

Lower-limb peripheral artery disease (PAD) is a prevalent and challenging complication of diabetes, requiring innovating therapies. Praliciguat is an orally available stimulator of soluble guanylate cyclase (sGC) reported to have favorable effects on metabolic and hemodynamic endpoints in preclinical and clinical studies, suggesting the potential for benefit in PAD. We evaluated the effect of praliciguat on hindlimb ischemia recovery in a mouse model of diabetes and investigated the molecular mechanism of sGC stimulation. Hindlimb ischemia was induced in db/db mice by ligation and excision of the left femoral artery. Praliciguat 10 mg/kg/day ( n = 10 mice) or vehicle ( n = 10) were administered in the diet for 31 days starting 3 days before surgery. Foot perfusion was assessed with a Laser Doppler Imager and reported as a ratio in the ischemic versus non-ischemic limb. Ischemic leg function was assessed with a 4-point scale: 0, plantar/toe flexion in response to tail traction; 1, plantar but not toe flexion; 2, no flexion; 3, foot dragging. Ischemic foot perfusion and function were better 28 days after surgery in praliciguat than in vehicle treated mice (mean ± SD: perfusion 1.05 ± 0.23 vs. 0.38 ± 0.16; P < 0.0001; function 1.14 ± 0.36 vs. 1.73 ± 0.80; P = 0.03). Praliciguat did not impact angiogenesis. Arteriolar diameter was higher (9.88 ± 0.96 vs. 8.57 ± 0.64 μm; P = 0.004) and ICAM-1 expression lower (186 ± 41 vs. 403 ± 177% of healthy muscle; P = 0.005) in the ischemic limb of mice treated with praliciguat than with vehicle. Praliciguat attenuated accumulation of oxidative pro-angiogenic and pro-inflammatory muscle fibers. In cultured myoblasts praliciguat significantly downregulated Myh2 and Cxcl12 mRNA expression. Conditioned medium from praliciguat-treated myoblast decreased ICAM-1 mRNA expression in HUVECs. These results suggest that praliciguat restored perfusion and function in the ischemic muscle of db/db mice by increasing arteriolar diameter and decreasing ICAM-1 expression in endothelial cells via downregulation of Cxcl12 in myocytes.

450-P: Soluble Guanylate Cyclase Stimulator Praliciguat Promotes Ischemic Leg Reperfusion in db/db Mice

Background: Lower-limb peripheral artery disease (PAD) is a prevalent and challenging complication of diabetes, requiring innovating therapies. Praliciguat is an orally available stimulator of soluble guanylate cyclase reported to have favorable effects on metabolic and hemodynamic endpoints in preclinical and clinical studies, suggesting the potential for benefit in PAD. We evaluated the effect of praliciguat on hindlimb ischemia recovery in a mouse model of diabetes. Methods: Hindlimb ischemia was induced in db/db mice by ligation and excision of the left femoral artery. Praliciguat 10mg/kg/day (N=mice) or vehicle (N=10) were administered in the diet for 31 days. Foot perfusion was assessed with a Laser Doppler Imager and reported as a ratio in the ischemic versus non-ischemic limb. Ischemic leg function was assessed with a 4-point scale: 0, plantar/toe flexion in response to tail traction; 1, plantar but not toe flexion; 2, no flexion; 3, foot dragging. Results: Ischemic foot perfusion and function were better 28 days after surgery in praliciguat than in vehicle treated mice (mean ± SD: perfusion 1.± 0.23 vs. 0.38 ± 0.16; p&amp;lt;0.0001; function 1.14 ± 0.36 vs. 1.73 ± 0.80; p=0.03) . Praliciguat did not impact angiogenesis. Arteriolar diameter was higher (9.88 ± 0.96 vs. 8.57 ± 0.64 µm; p=0.004) and ICAM-1 expression lower (186 ± 41 vs. 403 ± 177 % of healthy muscle; p=0.005) in the ischemic limb of mice treated with praliciguat than with vehicle. Praliciguat attenuated accumulation of oxidative pro-angiogenic and pro-inflammatory muscle fibers. In cultured myoblasts praliciguat significantly downregulated Myh2 and Cxcl12 mRNA expression. Conditioned medium from praliciguat-treated myoblast decreased ICAM-1 mRNA expression in HUVECs. Conclusion: These results suggest that praliciguat restored perfusion and function in the ischemic muscle of db/db mice by increasing arteriolar diameter and decreasing ICAM-1 expression in endothelial cells via downregulation of Cxcl12 in myocytes. Disclosure N.Foussard: None. E.S.Buys: Employee; Cyclerion Therapeutics, Inc. K.Mohammedi: Board Member; Lilly, Novo Nordisk, Sanofi, Research Support; Cyclerion Therapeutics, Inc., Speaker's Bureau; Abbott, AstraZeneca. M.Renault: None.

Abstract 500: Silencing Apolipoprotein C3 Prevents Diabetic Kidney Disease And Atherosclerosis In A Mouse Model Of Type 2 Diabetes

Diabetes increases the risk of both cardiovascular disease and kidney disease. Notably, most of the excess cardiovascular risk in people with diabetes is in those with kidney disease. Apolipoprotein C3 (APOC3) is a small apolipoprotein that is elevated by insulin-insufficiency and regulates plasma triglyceride levels. To test if APOC3, and the dyslipidemia it represents, play a role in diabetic kidney disease (DKD) and associated atherosclerosis, we treated BTBR wildtype (WT) and leptin-deficient (OB; diabetic) mice with an antisense oligonucleotide (ASO) to APOC3 or a control ASO (cASO), all in the setting of human-like dyslipidemia (accomplished by administration of an ASO targeting the LDLR). APOC3 ASO treatment reduced triglycerides, triglyceride-rich lipoproteins. It prevented diabetes-accelerated atherosclerosis in the aortic sinus, brachiocephalic artery, and aorta (sinus lesion: 67926 ± 8486 μm 2 lesion in cASO-treated OB mice compared to 38589 ± 9507 μm 2 in APOC3 ASO-treated OB mice, p&lt;0.05, n=12-15). The reduction in lesion size with APOC3 treatment was associated with fewer macrophages and reduced perilipin 2 staining (a marker for lipid droplet formation). In the kidney, diabetes resulted in a dramatic increase in glomerular hypertrophy, neutral lipid accumulation, APOC3, and APOE-accumulation, which APOC3 ASO-treatment attenuated. Furthermore, diabetes resulted in monocyte recruitment, macrophage accumulation, and macrophage lipid loading in the glomeruli, all of which was dramatically suppressed in the setting of APOC3 silencing (36% of glomerular macrophages were lipid loaded in OB cASO mice whereas only 9% were lipid loaded in APOC3-ASO treated mice, p&lt;0.0001). The recruitment was driven by increased endothelial cell ICAM1 expression, but monocyte lipid loading may also contribute. Intriguingly, APOC3-ASO treatment reduced diabetes-associated urinary albumin creatinine ratio but did not affect it in non-diabetic mice (WT mice: 374 ± 71 μg albumin/mg creatinine, OB cASO mice: 4648 ± 1021 μg/mg and OB mice with APOC3 ASO: 2341 ± 439 μg/mg, p&lt;0.05, n=12-14). Together, this suggests that targeting APOC3 and diabetic dyslipidemia might be beneficial for both diabetes-accelerated atherosclerosis and kidney disease.

CD40 Expressed in Endothelial Cells Promotes Upregulation of ICAM-1 But Not Pro-Inflammatory Cytokines, NOS2 and P2X7 in the Diabetic Retina.

PurposeCD40 is an upstream inducer of inflammation in the diabetic retina. CD40 is upregulated in retinal endothelial cells in diabetes. The purpose of this study was to determine whether expression of CD40 in endothelial cells is sufficient to promote inflammatory responses in the retina of diabetic mice.MethodsTransgenic mice with CD40 expression restricted to endothelial cells (Trg-CD40 EC), transgenic control mice (Trg-Ctr), B6, and CD40−/− mice were made diabetic using streptozotocin. Leukostasis was assessed using FITC-conjugated ConA. Pro-inflammatory molecule expression was examined by real-time PCR, immunohistochemistry, ELISA, or flow cytometry. Release of ATP was assessed by ATP bioluminescence.ResultsDiabetic B6 and Trg-CD40 EC mice exhibited increased retinal mRNA levels of ICAM-1, higher ICAM-1 expression in endothelial cells, and increased leukostasis. These responses were not detected in diabetic mice that lacked CD40 (CD40−/− and Trg-Ctr). Diabetic B6 but not Trg-CD40 EC mice upregulated TNF-α, IL-1β, and NOS2 mRNA levels. CD40 stimulation in retinal endothelial cells upregulated ICAM-1 but not TNF-α, IL-1β, or NOS2. CD40 ligation did not trigger ATP release by retinal endothelial cells or pro-inflammatory cytokine production in bystander myeloid cells. In contrast to diabetic B6 mice, diabetic Trg-CD40 EC mice did not upregulate P2X7 mRNA levels in the retina.ConclusionsEndothelial cell CD40 promotes ICAM-1 upregulation and leukostasis. In contrast, endothelial cell CD40 does not lead to pro-inflammatory cytokine and NOS2 upregulation likely because it does not activate purinergic-mediated pro-inflammatory molecule expression by myeloid cells or induce expression of these pro-inflammatory molecules in endothelial cells.

Platelet Microparticles Enriched in miR-223 Reduce ICAM-1-Dependent Vascular Inflammation in Septic Conditions.

In the process of sepsis, activated platelets shed microvesicles containing microRNAs (miRNAs), which can be internalized by distinct recipient cells in circulation, consequently eliciting a potent capability to regulate their cellular functions in different diseases. In the present study, activated human platelets transferring miR-223 into endothelial cells via platelet-derived microparticles (PMPs) was investigated in vitro during septic conditions with a proposed mechanism involving in downregulation of the enhanced expression of intercellular adhesion molecule-1 (ICAM-1). The uptake of PMPs encasing miR-223 and the adhesion of peripheral blood mononuclear cells (PBMCs) on human coronary artery endothelial cells (HCAECs) were observed by immunofluorescence microscopy upon co-culture with PMPs isolated from sepsis or control plasma. The expression of miR-223-3p and its gene target ICAM1 in HCAECs were quantified by RT-qPCR and ELISA after the cells were incubated with septic or control PMPs, whose levels were induced with thrombin-receptor activating peptide (TRAP). Leukocyte-depleted platelets (LDPs) from septic patients showed a decreased miR-223 level, while septic plasma and PMPs revealed an elevated miRNA level compared to control samples. Similarly, TRAP-activated LDPs demonstrated a reduced intracellular miR-223 expression, while increased levels in the supernatant and PMP isolates were observed vs. untreated samples. Furthermore, TNF-α alone resulted in decreased miR-223 and elevated ICAM1 levels in HCAECs, while PMPs raised the miRNA level that was associated with downregulated ICAM1 expression at both mRNA and protein levels under TNF-α treatment. Importantly, miR-223 was turned out not to be newly synthesized as shown in unchanged pre-miR-223 level, and mature miR-223 expression was also elevated in the presence of PMPs in HCAECs after transfection with Dicer1 siRNA. In addition, septic PMPs containing miR-223 decreased ICAM1 with a reduction of PBMC binding to HCAECs. In conclusion, septic platelets released PMPs carrying functional miR-223 lower ICAM1 expression in endothelial cells, which may be a protective role against excessive sepsis-induced vascular inflammation.

Hyperbaric Oxygen Exposure Reduces ICAM-1 And HIF1? Expression in Brain Endothelial Cells from Experimental Cerebral Malaria Mice

This study aimed to reveal the role of ICAM-1 and HIF-1? in brain endothelial cell of cerebral malariamice model after exposure to 2.4 absolute atmospheres (ATA) hyperbaric oxygen (HBO). Thirty-nineC57BL/6 mice were divided into three groups: control negative (normal mice without any exposure),control positive (Plasmodium berghei ANKA [PbA] infection without HBO exposure), and treatment (PbAinfection and exposed to HBO for 10 sessions after the parasite grew). Parasitemia and clinical symptomswere observed every day. Brain tissues were isolated on day 13 post-infection for histopathological andimmunohistochemical examination (observed at 400x magnification in 10 visual fields). HBO decreasedHIF-1? and ICAM-1 expression in endothelial cells. There was a moderate correlation between HIF-1? andICAM-1 expression. Ten HBO sessions prevented cerebral malaria, as denoted by the decreased expressionof ICAM-1 and HIF-1? in brain vascular endothelial cells from the experimental mice.

Calreticulin induced endothelial ICAM-1 up-regulation associated with tristetraprolin expression alteration through PI3K/Akt/eNOS/p38 MAPK signaling pathway in rheumatoid arthritis

The present study was undertaken to determine whether extracellular calreticulin (CRT) participates in the regulation of ICAM-1in rheumatoid arthritis (RA) and further explore the potential mechanism. Our results showed that ICAM-1 and VCAM-1 levels were positively correlated with CRT levels in RA serum and synovial fluid, respectively. In RA synovial tissue, increased co-expressions of CRT and ICAM-1 in vascular endothelium and perivascular areas and elevated co-location of CRT and VCAM-1 localized predominantly to lining layer were observed compared to those in OA. In in vitro HUVECs model, enhanced ICAM-1expression and increased phosphorylation levels of Akt and eNOS were detected in the presence of CRT. Increased phosphorylated eNOS was significantly inhibited by a PI3K inhibitor LY294002 and elevated ICAM-1expression was partially blocked by the inhibitors of both PI3K and eNOS (L-NAME). It has been certified that the RNA-binding protein TTP targets AU-rich elements in the ICAM-1 3′-UTR and suppresses ICAM-1 expression. Knocking down TTP in HUVECs led to an increased induction of ICAM-1 by CRT. We have currently known that activation of p38 downstream kinase MK-2 leads to phosphorylation and inactivation of human TTP. The block of p38 MAPK/MK-2 signaling led to decreased protein expression and mRNA stability of TTP and ICAM-1. Furthermore, L-NAME and/or LY294002 pre-treated HUVECs manifested decreased p38 and MK-2 phosphorylation, which was accompanied by reduced TTP and ICAM-1 protein expression as well as decreased mRNA stability. Our results suggested that CRT could promote ICAM-1 expression in endothelial cells through PI3K/Akt/eNOS/p38 MAPK signaling mediated TTP accumulation, probably in an inactive form, which may provide a possible proinflammatory mechanism of CRT in RA.

Angiopoietin-Like Protein 3 Directly Regulates HDL Metabolism and Function

Background: Angiopoietin-like protein 3 (ANGPTL3) is produced by hepatocytes. Once secreted, it inhibits endothelial lipase activity and regulates angiogenesis. We previously reported the positive association between serum ANGPTL3 and HDL function in nondiabetic participants. Hereby, we investigated whether ANGPTL3 directly modulates HDL function. Methods: HDLs were isolated from plasma. ANGPTL3 in HDLs was studied by western blot and ELISA. Cholesterol efflux to HDLs was analyzed in macrophages preloaded with fluorescent cholesterol. Recombinant human ANGPTL3 was subjected to endothelial cells treated with TNF-α and ICAM-1 expression was analyzed by FACS. Similar experiments were repeated in db mice injected with AAV encoding human ANGPTL3 cDNA or shRNA. Results: ANGPTL3 was present in human HDLs, which were lower in T2DM patients than controls (p=0.04). ANGPLT3 in HDLs was positively associated with cholesterol efflux in nondiabetic controls (r=0.33, p=0.044) but not in T2DM patients (r=0.05, p=0.77). Recombinant ANGPTL3 reduced ICAM-1 expression in endothelial cells exposed to TNF-α (p=0.0001). Similarly, ANGPTL3 levels in HDLs were lower in db mice at 18 weeks old than 8 weeks old, which was accompanied with reduced cholesterol reflux to HDLs and rendered inhibition of ICAM-1 expression in endothelial cells (p&amp;lt;0.for all). Following AAV-mediated ANGPTL3 cDNA transfer, ANGTL3 levels were increased in HDLs of db mice, which increased cholesterol efflux and decreased ICAM-1 expression compared with db mice with vector transfer. Vice versa, decreased ANGPTL3 levels in HDLs by AAV-mediated shRNA transfer abrogated HDL function mentioned above (p&amp;lt;0.for both). When placed on high fat diet for 10 weeks, atherosclerotic plaque was larger in db mice with ANGPTL3 shRNA transfer than other gene transferred groups (p&amp;lt;0.05). Conclusion: ANGPTL3 is a HDL component and direct regulates HDL function. Decrease of ANGPTL3 expression may reduce HDL function and accelerate atherosclerosis in T2DM. Disclosure L. Yang: None. Y. Wang: None. Y. Fu: None. J. Lang: None. D. Zhao: None. Y. Feng: None.

Post‐septic Down‐regulation of Sulfatase‐1 Suppresses Pulmonary Endothelial ICAM‐1 Expression

RationalePost‐septic compensatory anti‐inflammatory syndrome (CARS) is a state of immunoparalysis that leaves patients susceptible to secondary infections. Interestingly, CARS coincides with post‐septic reconstitution of the pulmonary endothelial glycocalyx, a heparan sulfate (HS)‐enriched layer that regulates endothelial‐neutrophil adhesion and is degraded during early sepsis. CARS is generally described as a consequence of impaired leukocyte function, with little understanding of the role of the post‐septic endothelium. We hypothesized that the post‐septic pulmonary endothelial glycocalyx is characterized by changes in HS sulfation (via changes in sulfatase expression), leading to impaired endothelial inflammatory responses.MethodsWe induced sepsis in male C57BL/6J mice with cecal ligation and puncture (CLP). To recapitulate CARS, post‐septic mice (3 days after CLP) animals were treated with intratracheal lipopolysaccharide (LPS), and the degree of inflammation was assessed thereafter by bronchoalveolar lavage (BAL) cell count and protein concentration. To determine changes in post‐septic pulmonary endothelial gene expression during CARS, we flow‐sorted pulmonary endothelial cells and performed RNA microarray and confirmatory qRT‐PCR. To determine post‐septic changes in HS sulfation, we performed mass spectrometry of HS isolated from either the pulmonary endothelial glycocalyx or the plasma of post‐CLP or post‐sham mice. We determined the impact of altered endothelial HS sulfation on CARS by either (a) degrading HS from the endothelial glycocalyx by intravenous heparinase I or (b) administering exogenous sulfated HS intravenously prior to intratracheal LPS. We specifically measured the effect of sulfatase‐1 (sulf‐1, an extracellular enzyme that specifically cleaves 6‐O sulfate of HS) on endothelial cell ICAM‐1 expression using siRNA.ResultsIn comparison to sham mice, post‐septic mice showed decreased cellular and protein infiltration in BAL fluid 48 hrs after intratracheal LPS (n=5–6, P &lt; 0.05). Microarray and qRT‐PCR analyses of flow‐sorted endothelial cells (harvested 48 hrs after CLP or sham) detected downregulation of sulf‐1 in CLP mice (n=3–4, P &lt; 0.05). While these changes correlated with increased 6‐O sulfation in the endothelial glycocalyx and circulating HS, experimental modulation of these HS compartments did not influence CARS. However, in vitro, transfection of siRNA targeted to sulf‐1 resulted in 90% reduction of sulf‐1 mRNA and down‐regulation of ICAM‐1 by 57–70% (n=2). These in vitro changes surprisingly occurred independently of HS 6‐O sulfation.ConclusionsConcurrently with CARS, post‐septic pulmonary endothelial cells undergo downregulation of sulf‐1, causing loss of endothelial ICAM‐1 expression. Surprisingly, this impaired ICAM‐1 expression occurred in the absence of changes in HS 6‐O sulfation.Support or Funding InformationDepartment of Defense PR150655 (to EPS)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Inhibition of IL-8-mediated endothelial adhesion, VSMCs proliferation and migration by siRNA-TMEM98 suggests TMEM98's emerging role in atherosclerosis.

Transmembrane protein 98 (TMEM98), known as a novel gene related to lung cancer, hepatocellular carcinoma, differentiation of T helper 1 cells and normal eye development, has no defined role reported in terms of atherosclerosis (AS). To investigate the potential involvement of TMEM98 during AS processes, its obvious secretion and expression has been initially characterized in hyperlipidemia patients’ serum and AS mice's serum respectively. We then explored the possible role of TMEM98 in the pathogenesis of AS in vitro. IL-8, a pro-atherogenesis cytokine, was used to induce the expression of TMEM98 in both endothelial cells (ECs) and vascular smooth muscle cells (VSMCs). Collectively, TMEM98 expression significantly increased in ECs and VSMCs, both induced by IL-8. Additionally, the adhesion ability of monocytes to ECs as well as the proliferation and migration of VSMCs were all decreased after siRNA-TMEM98 treatment. Furthermore, siRNA-TMEM98 dramatically inhibited the expression of ICAM-1 in ECs and the expression of p-AKT, p-GSK3β and Cyclin D1 from VSMCs, and AKT agonist partially restored the proliferation and migration of VSMC after siRNA-TMEM98 treatment. Taken together, siRNA-TMEM98 inhibits IL-8 mediated EC adhesion by down-regulating the expression of ICAM-1. Additionally, it also hinders the proliferation and migration of VSMCs through suppressing the AKT/GSK3β/Cyclin D1 signaling pathway. Our study provides sufficient evidence to support that TMEM98 could be a novel gene associated with AS for the first time.

Platelets modulate endothelial cell response to dynamic shear stress through PECAM-1

IntroductionBoth vascular endothelial cells and platelets are sensitive to blood flow induced shear stress. We have recently reported that platelet-endothelial cell interaction could greatly affect platelet activation under flow. In the present study, we aimed to investigate how platelet-endothelial cell interaction affected endothelial cell inflammatory responses under flow. Materials and methodsHuman coronary artery endothelial cells were exposed to normal or low pulsatile shear stress with or without the presence of platelets. Following shear exposure, endothelial cell ICAM-1 expression was measured using ELISA, Western blot and PCR; cell surface PECAM-1 expression/phosphorylation was measured using ELISA. Platelet adhesion to endothelial cells was quantified using immunofluorescence microscopy. To determine the role of PECAM-1 in platelet-endothelial cell interaction, endothelial cell PECAM-1 expression was suppressed using siRNA. ResultsPathological low shear stress induced a significant increase in endothelial cell ICAM-1 expression, at both protein and mRNA levels. Platelet adhesion to endothelial cells increased significantly under low shear stress, co-localizing with PECAM-1 at endothelial cell junctions. The presence of platelets inhibited low shear stress-induced ICAM-1 upregulation. When endothelial cell PECAM-1 expression was suppressed, platelet adhesion to endothelial cells under low shear stress decreased significantly; endothelial cell ICAM-1 expression was not affected by shear stress, with or without platelets. ConclusionsThese results suggested that PECAM-1 could mediate platelet adhesion to endothelial cells under shear stress. Platelets binding to endothelial cells interfered with endothelial cell mechanotransduction through PECAM-1, affecting endothelial cell inflammatory responses towards pathological shear flow.

Novel approach to study the cardiovascular effects and mechanism of action of urban particulate matter using lung epithelial-endothelial tetra-culture system

In vitro models have become increasingly sophisticated, and their usefulness in supporting toxicity testing is well established. The present study was designed to establish a novel in vitro model that mimics the cellular network surrounding airways and pulmonary blood vessels, to study the cardiovascular toxic effects of particulate matter (PM). Transwell culture method was used to develop a novel tetra-culture system consisting of tri-cultures (one lung epithelial and two immune cell lines) in the apical chamber and endothelial cells in the basolateral chamber. Tri-cultures were exposed to standard reference material (SRM) 1648a, an urban PM. SRM 1648a did not show cytotoxic effects; however, it increased IL-6 level in apical and basolateral chambers. The cells in the basolateral chamber showed increased monocyte adhesion. Furthermore, exposure of tri-cultured cells to SRM 1648a in the apical chamber induced ICAM-1 expression in endothelial cells in the basolateral chamber by activating the IL-6/STAT3 pathway. In conclusion, a tetra-culture system was established to facilitate the identification of cellular adhesion molecule expression induced by the interaction between pulmonary epithelial and endothelial cells. The tetra-culture system will contribute to elucidation of the relationships between inhalable PM and cardiovascular diseases.

AMA0428, A Potent Rock Inhibitor, Attenuates Early and Late Experimental Diabetic Retinopathy

ABSTRACTPurpose: Diabetic retinopathy (DR) is characterized by an early stage of inflammation and vessel leakage, and an advanced vasoproliferative stage. Also, neurodegeneration might play an important role in disease pathogenesis. The aim of this study was to investigate the effect of the Rho kinase (ROCK) inhibitor, AMA0428, on these processes.Methods: The response to ROCK inhibition by AMA0428 (1 µg) was studied in vivo using the murine model for streptozotocin (STZ)-induced diabetes, focusing on early non-proliferative DR features and the oxygen-induced retinopathy (OIR) model to investigate proliferative DR. Intravitreal (IVT) administration of AMA0428 was compared with murine anti-VEGF-R2 antibody (DC101, 6.2 µg) and placebo (H2O/PEG; 1C8). Outcome was assessed by analyzing leukostasis using fluorescein isothiocyanate coupled concanavalin A (FITC-ConA) and vessel leakage (bovine serum albumin conjugated with fluorescein isothiocyanate; FITC-BSA)/neovascularization and neurodegeneration by immunohistological approaches (hematoxylin and eosin (H&E), terminal deoxynucleotidyl transferase–mediated biotinylated UTP nick end labeling (TUNEL), Brn3a). ELISA and Western blotting were employed to unravel the consequences of ROCK inhibition (1 µM AMA0428) on myosin phosphatase target protein (MYPT)-1 phosphorylation, endothelial nitric oxide synthase (eNOS) phosphorylation, and vascular endothelial growth factor (VEGF) levels in retinas of diabetic mice, on NF-κβ activity and ICAM-1 expression in endothelial cells (ECs).Results: In vivo, AMA0428 significantly reduced vessel leakage and neovascularization, respectively, in the STZ and OIR model, comparable to DC101 therapy. Additionally, the ROCK inhibitor decreased neurodegeneration in both models and inhibited leukostasis by 30% (p < 0.05) in the STZ model (p < 0.05), while DC101 had no positive effect on the outcome of these latter processes. ROCK activity was upregulated in the diabetic retina and AMA0428 administration resulted in decreased phospho-MYPT-1, enhanced phospho-eNOS, and reduced VEGF levels. In vitro, AMA0428 interfered with NF-κβ activity, thereby inhibiting ICAM-1 expression in ECs.Conclusions: Targeting ROCK with AMA0428 effectively attenuated outcome in an early DR model (STZ) and a late vasoproliferative retinopathy model (OIR). These findings make AMA0428 a promising candidate with an additional anti-inflammatory and neuroprotective benefit for DR patients, as compared with anti-VEGF treatment.

Ac-SDKP suppresses TNF-α-induced ICAM-1 expression in endothelial cells via inhibition of IκB kinase and NF-κB activation.

N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) is a naturally occurring tetrapeptide that prevents inflammation and fibrosis in hypertension and other cardiovascular diseases. We previously showed that, in angiotensin II-induced hypertension, Ac-SDKP decreased the activation of nuclear transcription factor NF-κB, whereas, in experimental autoimmune myocarditis and hypertension animal models, it also reduced the expression of endothelial leukocyte adhesion molecule ICAM-1. However, the mechanisms by which Ac-SDKP downregulated ICAM-1 expression are still unclear. TNF-α is a proinflammatory cytokine that induces ICAM-1 expression in various cell types via TNF receptor 1 and activation of the classical NF-κB pathway. We hypothesized that in endothelial cells Ac-SDKP suppresses TNF-α-induced ICAM-1 expression by decreasing IKK phosphorylation that as a consequence leads to a decrease of IκB phosphorylation and NF-κB activation. To test this hypothesis, human coronary artery endothelial cells were treated with Ac-SDKP and then stimulated with TNF-α. We found that TNF-α-induced ICAM-1 expression was significantly decreased by Ac-SDKP in a dose-dependent manner. Ac-SDKP also decreased TNF-α-induced NF-κB translocation from cytosol to nucleus, as assessed by electrophoretic mobility shift assay, which correlated with a decrease in IκB phosphorylation. In addition, we found that Ac-SDKP decreased TNF-α-induced IKK phosphorylation and IKK-β expression. However, Ac-SDKP had no effect on TNF-α-induced phosphorylation of p38 MAP kinase or ERK. Thus we conclude that Ac-SDKP inhibition of TNF-α activation of canonical, i.e., IKK-β-dependent, NF-κB pathway and subsequent decrease in ICAM-1 expression is achieved via inhibition of IKK-β.

Effect of salvianolic acid B on TNF-α induced cerebral microcirculatory changes in a micro-invasive mouse model

PurposeTo investigate the effects of salvianolic acid B (SAB) on tumor necrosis factor α (TNF-α) induced alterations of cerebral microcirculation with a bone-abrading model. MethodsThe influences of craniotomy model and bone-abrading model on cerebral microcirculation were compared. The bone-abrading method was used to detect the effects of intracerebroventricular application of 40 μg/kg·bw TNF-α on cerebral venular leakage of fluorescein isothiocyanate (FITC)-albulmin and the rolling and adhesion of leukocytes on venules with fluorescence tracer rhodamine 6G. The therapeutical effects of SAB on TNF-α induced microcirculatory alteration were observed, with continuous intravenous injection of 5 mg/kg·h SAB starting at 20 min before or 20 min after TNF-α administration, respectively. The expressions of CD11b/CD18 and CD62L in leukocytes were measured with flow cytometry. Immunohistochemical staining was also used to detect E-selectin and ICAM-1 expression in endothelial cells. ResultsCompared with craniotomy method, the bone-abrading method preserved a higher erythrocyte velocity in cerebral venules and more opening capillaries. TNF-α intervention only caused responses of vascular hyperpermeability and leukocyte rolling on venular walls, without leukocyte adhesion and other hemodynamic changes. Pre- or post-SAB treatment attenuated those responses and suppressed the enhanced expressions of CD11b/CD18 and CD62L in leukocytes and E-selectin and ICAM-1 in endothelial cells induced by TNF-α. ConclusionsThe pre- and post-applications of SAB during TNF-α stimulation could suppress adhesive molecular expression and subsequently attenuate the increase of cerebral vascular permeability and leukocyte rolling.