The microtubule system in endothelial barrier dysfunction: disassembly of peripheral microtubules and microtubules reorganization in internal cytoplasm

Endothelial cell barrier dysfunction is often associated with dramatic cytoskeletal reorganization, activation of actomyosin contraction and finally gap formation. At present time the role of microtubules in endothelial cell barrier regulation is not fully understood, however a number of observations allow to assume that microtubules reaction is the extremely important part in development of endothelial dysfunction. These observations have been forced us to examine the role of microtubule system reorganization in endothelial cell barrier regulation. In quiescent endothelial cells microtubule density is the highest in the centrosome region and insignificant near the cell margin. The analysis of microtubules distribution after specific antibodies staining using the method of measurement of their fluorescence intensity has shown that in control endothelial cells the reduction of fluorescence intensity from the cell center to its periphery is described by the equation of an exponential regression. The hormone agent, thrombin (25 nM), causes rapid increase of endothelial cell barrier permeability accompanied by fast decrease in quantity of peripheral microtubules and reorganization of microtubule system in internal cytoplasm of endothelial cells (the decrease of fluorescence intensity is described by the equation of linear regress already through 10 min after the beginning of the treatment). Both effects are reversible -- through 60 min after the beginning of the treatment the microtubule network does not differ from normal one, so the microtubule system is capable to adapt for influence of a natural regulator thrombin. The microtubules reaction develops more quickly, than reorganization of the actin filaments system, which responsible for the subsequent changes in the cell shape during barrier dysfunction. Apparently, the microtubules are the first part in a circuit of the reactions leading to the pulmonary endothelial cell barrier compromise.     

Phosphatase 2A is involved in endothelial cell microtubule remodeling and barrier regulation

We have recently shown that microtubule (MT) inhibitor, nocodazole (2-5 microM) significantly increases endothelial cells (EC) actomyosin contraction and permeability indicating the importance of MT in maintaining the EC barrier (Verin et al. [2001]: Cell Mol Physiol 281:L565-L574). Okadaic acid (OA, 2-5 nM), a powerful inhibitor of protein phosphatase 2A (PP2A), significantly potentiates the effect of submaximal concentrations of nocodazole (50-200 nM) on transendothelial electrical resistance (TER) suggesting the involvement of PP2A activity in the MT-mediated EC barrier regulation. Immunofluorescent staining of EC revealed that in control cells PP2A distributes in a pattern similar to MT. Consistent with these results, we demonstrated that significant amounts of PP2A were present in MT-enriched EC fractions indicating tight association of PP2A with MT in endothelium. Treatment of EC with OA leads to disappearance of MT-like PP2A staining suggesting dissociation of PP2A from the MT network. Next, we examined the effect of PP2A inhibition on phosphorylation status of MT-associated protein tau, which in its unphosphorylated form promotes MT assembly. OA caused significant increases in tau phosphorylation confirming that tau is a substrate for PP2A in endothelium. Immunofluorescent experiments demonstrated that the OA-induced increases in tau phosphorylation strongly correlated with translocation of phospho-tau to cell periphery and disassembly of peripheral MT. These results suggest the involvement of PP2A-mediated tau dephosphorylation in alteration of EC MT structure and highlight the potential importance of PP2A in the regulation of EC the MT cytoskeleton and barrier function.     

Sites of actin filament initiation and reorganization in cold-treated tobacco cells

Cytoskeletal proteins assemble into dynamic polymers that play many roles in nuclear and cell division, signal transduction, and determination of cell shape and polarity. The distribution and dynamics of microtubules (MTs) and actin filaments (AFs) are determined, among other factors, by the location of their nucleation sites. Whereas the sites of microtubule nucleation in plants are known to be located under the plasma membrane and on the nuclear envelope during interphase, there is a striking lack of information about nucleation sites of AFs. In the studies reported herein, low temperature (0 °C) was used to de‐polymerize AFs and MTs in tobacco BY‐2 (Nicotiana tabacum L.) cells at interphase. The extent of de‐polymerization of cytoskeletal filaments in interphase cells during cold treatment and the subcellular distribution of nucleation sites during subsequent recovery at 25 °C were monitored by means of fluorescence microscopy. The results show that AFs re‐polymerized rapidly from sites located in the cortical region and on the nuclear envelope, similarly to the initiation sites of MTs. In contrast to MTs, however, complete reconstitution of AFs was preceded by the formation of transient actin structures including actin dots, rods, and filaments with a dotted signal. Immunoblotting of soluble and sedimentable protein fractions showed no changes in the relative amounts of free and membrane‐bound actin or tubulin.     

脂多糖致急性肺血管内皮屏障功能失调小鼠FLI-1蛋白表达的变化及其意义

目的: 观察感染性急性肺损伤(ALI)肺血管内皮屏障功能失调小鼠肺组织中弗里德白血病病毒插入位点1(FLI-1)蛋白表达的变化,以探讨FLI-1在感染性ALI肺血管内皮屏障功能失调发生发展中的意义。方法: SPF级雄性ICR小鼠60只,腹腔注射脂多糖(LPS,7.5 mg/kg)复制ALI模型,在给予LPS 0 h、12 h、24 h、48 h后,检测小鼠肺血管内皮屏障通透性和肺湿干重比,ELISA法检测肺泡灌洗液中TNF-α和IL-6含量,Western blot法检测肺组织FLI-1和Src酪氨酸激酶(SRC)蛋白的表达。结果: 与0 h组比较,12 h组、24 h组肺血管内皮屏障通透性分别升高74.3%和162.4%,而48 h组较24 h组降低27.0%(P均＜0.05);与0 h组比较,12 h组、24 h组肺湿干重比分别升高50.1%和122.9%,而48 h组较24 h组降低10.7%(P均＜0.05);与0 h组比较,12 h、24 h肺泡灌洗液IL-6和TNF-α含量均显著升高,而48 h肺泡灌洗液IL-6和TNF-α含量较24 h分别下降28.3%和21.6%(P均＜ 0.05);与0 h组比较,12 h组、24 h组肺组织FLI-1蛋白表达水平分别下调20.4%和56.9%,而48 h组较24 h组上调18.2%(P均＜0.05);与0 h组比较,12 h组、24 h组肺组织SRC蛋白表达水平分别上调76.8%和176.7%,而48 h组较24 h组下调33.4%(P均＜0.05);肺血管内皮屏障通透性与FLI-1蛋白表达水平呈显著负相关(r= -0.8992,P＜0.01),而与SRC蛋白表达水平呈显著正相关(r=0.8918,P＜0.01),肺组织FLI-1与SRC蛋白表达呈显著负相关(r=-0.8087,P=0.0014)。结论: FLI-1可能参与LPS诱导的急性肺损伤肺血管内皮屏障功能失常过程。     

Subpopulations of tau interact with microtubules and actin filaments in various cell types

It has been demonstrated that microtubule-associated proteins (MAPs) interact with tubulin in vitro and in vivo. However, there is no clear evidence on the possible roles of the interactions of MAPs in vivo with other cytoskeletal components in maintaining the integrity of the cell architecture. To address this question we extracted the neuronal cytoskeleton from brain cells and studied the selective dissociation of specific molecular isospecies of tau protein under various experimental conditions. Tau, and in some cases MPA-2, were analysed by the use of anti-idiotypic antibodies that recognize epitopes on their tubulin binding sites. Fractions of microtubule-bound tau isoforms were extracted with 0.35 M NaCl or after the addition of nocodazole to allow microtubule depolymerization. Protein eluted with this inhibitor contained most of the assembled tubulin dimer pool and part of the remaining tau and MAP-2. When the remaining cytoskeletal pellet was treated with cytochalasin D to allow depolymerization of actin filaments, only tau isoforms were extracted. Immunoprecipitation studies along with immunolocalization experiments in cell lines containing tau-like components supported the findings on the roles of tau isospecies as linkers between tubulin in the microtubular structure with actin filaments. Interestingly, in certain types of cells, antibody-reactive tau isospecies were detected by immunofluorescence with a discrete distribution pattern along actin filaments, which was affected by cytochalasin disruption of the actin filament network. These results suggest the possible in vivo roles of subsets of tau protein in modulating the interactions between microtubules and actin filaments.     

Platelet endothelial cell adhesion molecule‐1 (PECAM1) plays a critical role in the maintenance of human vascular endothelial barrier function

Cardiovascular endothelial barrier dysfunction is associated with a number of cardiovascular diseases. This study aims to investigate the role of platelet endothelial cell adhesion molecule‐1 (PECAM1) in the maintenance of the vascular endothelial barrier integrate. Human umbilical vein endothelial cells (HUVECs) were cultured into monolayers using as an in vitro model to assess the endothelial barrier function. Knockdown of the gene of PECAM1 markedly reduced the transendothelial resistance and increased the permeability of the HUVEC monolayers. From the wild HUVECs, we detected a complex of PECAM1, claudin1, occluding and endothelial cell selective adhesion molecule (ESAM); such a complex was not detected in the PECAM1‐deficient HUVECs. Knockdown of either claudin1, or occludin, or ESAM, did not affect the formation of the tight junction (TJ) complex. Exposure to recombinant interleukin (IL)‐13 inhibited the expression of PECAM1 and down‐regulated the HUVEC monolayer barrier function. PECAM1 plays an important role in the formation of TJ complex. Copyright © 2015 John Wiley & Sons, Ltd.     

The morphogenesis of lobed plant cells in the mesophyll and epidermis: organization and distinct roles of cortical microtubules and actin filaments

The morphogenesis of lobed plant cells has been considered to be controlled by microtubule (MT) and/or actin filament (AF) organization. In this article, a comprehensive mechanism is proposed, in which distinct roles are played by these cytoskeletal components. First, cortical MT bundles and, in the case of pavement cells, radial MT arrays combined with MT bundles determine the deposition of local cell wall thickenings, the cellulose microfibrils of which copy the orientation of underlying MTs. Cell growth is thus locally prevented and, consequently, lobes and constrictions are formed. Arch-like tangential expansion is locally imposed at the external periclinal wall of pavement cells by the radial arrangement of cellulose microfibrils at every wall thickening. Whenever further elongation of the original cell lobes occurs, AF patches assemble at the tips of growing lobes. Intercellular space formation is promoted or prevented by the opposite or alternate, respectively, arrangement of cortical MT arrays between neighboring cells. The genes that are possibly involved in the molecular regulation of the above morphogenetic procedure by MT and AF array organization are reviewed.     

Low concentration of LatB dramatically changes the microtubule organization and the timing of vegetative nucleus/generative cell entrance in tobacco pollen tubes

Low concentration of LatB inhibits not only the actin polymerization, but also induces profound alteration of MT distribution in pollen tubes of Nicotiana tabacum. The short randomly oriented MTs in the apical and subapical regions, became organized as bundles forming subapical rings or basket-like structures, surrounding the apex. Moreover, the depolymerization of AFs in the cortical regions of the apex and subapical region affects the timing of entrance of the vegetative nucleus and generative cell into the pollen tube.     

Ischemic preconditioning and superoxide dismutase protect against endothelial dysfunction and endothelium glycocalyx disruption in the postischemic guinea-pig hearts

The effect of ischemic preconditioning and superoxide dismutase (SOD) on endothelial glycocalyx and endothelium-dependent vasodilation in the postischemic isolated guinea-pig hearts was examined. Seven groups of hearts were used: group 1 underwent sham aerobic perfusion; group 2 was subjected to 40 min global ischemia without reperfusion; group 3, 40 min ischemia followed by 40 min reperfusion; group 4 was preconditioned with three cycles of 5 min global ischemia followed by 5 min of reperfusion (IPC), prior to 40 min ischemia; group 5 was subjected to IPC prior to standard ischemia/reperfusion; group 6 underwent standard ischemia/reperfusion and SOD infusion (150 U/ml) was begun 5 min before 40 min ischemia and continued during the initial 5 min of the reperfusion period; group 7 was subjected to 80 min aerobic perfusion with NO-synthase inhibitor, L-NAME, to produce a model of endothelial dysfunction independent from the ischemia/reperfusion. Coronary flow responses to acetylcholine (ACh) and sodium nitroprusside (SNP) were used as measures of endothelium-dependent and endothelium-independent vascular function, respectively. Reduction in coronary flow caused by NO-synthase inhibitor, L-NAME, served as a measure of a basal endothelium-dependent vasodilator tone. After completion of each experimental protocol, the hearts were stained with ruthenium red or lanthanum chloride for electron microscopy evaluation of the endothelial glycocalyx. While ischemia led only to a slightly flocculent appearance of the glycocalyx, in ischemia/reperfused hearts the glycocalyx was disrupted, suggesting that it is the reperfusion injury which leads to the glycocalyx injury. Moreover, the coronary flow responses to ACh and L-NAME were impaired, while the responses to SNP were unchanged in the ischemia/reperfused hearts. The disruption of the glycocalyx and the deterioration of ACh and L-NAME responses was prevented by IPC. In addition, the alterations in the glycocalyx and the impairment of ACh responses were prevented by SOD. The glycocalyx appeared to be not changed in the hearts subjected to 80 min aerobic perfusion with L-NAME. In conclusion: (1) the impairment of the endothelium-dependent coronary vasodilation is paralleled by the endothelial glycocalyx disruption in the postischemic guinea-pig hearts; (2) both these changes are prevented by SOD, suggesting the role of free radicals in the mechanism of their development; (3) both changes are prevented by IPC. We hypothesize, therefore, that alterations in the glycocalyx contribute to the mechanism of the endothelial dysfunction in the postischemic hearts.     

Hypoxic trophoblast‐derived sFlt‐1 may contribute to endothelial dysfunction: implication for the mechanism of trophoblast—endothelial dysfunction in preeclampsia

The maternal systemic disorder of widespread endothelial dysfunction is a primary focus in understanding the development of preeclampsia. sFlt‐1 (soluble fms‐like tyrosine kinase receptor 1), an endogenous inhibitor of VEGF (vascular endothelial growth factor), may play important roles in endothelial dysfunction. The present study aimed to determine whether hypoxic trophoblast‐derived sFlt‐1 could lead to endothelial dysfunction by establishing a cocultured model of anoxic TEV‐1s (human first‐trimester extravillous trophoblasts) and HUVECs (human umbilical vein endothelial cells). The results showed that the hypoxic treatment significantly promoted sFlt‐1 mRNA and protein expression in TEV‐1s in a time‐dependent manner compared with the effect in HUVECs. When HUVECs were cocultured with anoxic TEV‐1s, the endothelial function, which was characterized by NO (nitric oxide) synthesis and monolayer barrier function of HUVECs, were notably decreased, accompanied by increasing sFlt‐1 and decreasing VEGF in cell‐conditioned medium. Moreover, the observed endothelial dysfunction described above was consistent with the dysfunction observed in VEGF siRNA‐treated cultures. The findings presented herein imply that chronically hypoxic trophoblasts may release sufficient sFlt‐1 to cause endothelial dysfunction by depriving cells of VEGF activity.     

P-glycoprotein in blood-brain barrier endothelial cells: interaction and oligomerization with caveolins

P-glycoprotein (P-gp), an adenosine triphosphate (ATP)-binding cassette transporter which acts as a drug efflux pump, is highly expressed at the blood-brain barrier (BBB) where it plays an important role in brain protection. Recently, P-gp has been reported to be located in the caveolae of multidrug-resistant cells. In this study, we investigated the localization and the activity of P-gp in the caveolae of endothelial cells of the BBB. We used an in vitro model of the BBB which is formed by co-culture of bovine brain capillary endothelial cells (BBCEC) with astrocytes. Caveolar microdomains isolated from BBCEC are enriched in P-gp, cholesterol, caveolin-1, and caveolin-2. Moreover, P-gp interacts with caveolin-1 and caveolin-2; together, they form a high molecular mass complex. P-gp in isolated caveolae is able to bind its substrates, and the caveolae-disrupting agents filipin III and nystatin decrease P-gp transport activity. In addition, mutations in the caveolin-binding motif present in P-gp reduced the interaction of P-gp with caveolin-1 and increased the transport activity of P-gp. Thus, P-gp expressed at the BBB is mainly localized in caveolae and its activity may be modulated by interaction with caveolin-1.     

Free radical-induced endothelial membrane dysfunction at the site of blood-brain barrier: Relationship between lipid peroxidation,Na,K-ATPase activity,and51Cr release

Na,K-ATPase activity, membrane lipid peroxidation (TBARM), and membrane leakiness for small molecules were examined in rat cerebromicrovascular endothelial cells (RCEC) following exposure to hydrogen peroxide and xanthine/xanthine oxidase. Whereas short-term (15–30 min) exposure to either oxidant decreased ouabain-sensitive⁸⁶Rb uptake and increased TBARM in a concentration-dependent fashion, significant release of⁵¹Cr (30–40%) from cells was observed only after one hour exposure to the oxidants. By comparison, much longer exposure times (i.e., 4 hours) were needed to induce significant lactate dehydrogenase release from oxidant-treated cells. The oxidant-evoked decrease in Na,K-ATPase activity and increases in TBARM and RCEC permeability were abolished in the presence of the steroid antioxidants U-74500A and U-74389G (5–20 M). Reduced glutathione (4 mM) partially attenuated oxidant-induced changes, whereas ascorbic acid (2 mM) and the disulfide bond-protecting agent, dithiothreitol (1 mM), were ineffective. These results suggest that the oxidant-induced loss of Na,K-ATPase activity in RCEC results primarily from changes in membrane lipids, and implicate both the inhibition of Na,K-ATPase and membrane lipid peroxidation in the mechanism responsible for the delayed free radical-induced increase in RCEC membrane permeability.     

Growth of brain microvessel endothelial cells on collagen gels: Applications to the study of blood-brain barrier physiology and CNS inflammation

Summary Brain microvessel endothelial cells (BMEC) exhibit the tendency to migrate through 3.0-vm pore semipermeable inserts and establish monolayers on both apical and basal filter surfaces. This can potentially lead to complications in accurately assessing a wide variety of physiologic parameters uniquely associated with these cells. To avoid this problem, we have explored growing BMEC on Transwell filters coated with hydrated collagen gels. BMEC seeded on such gels grow as a monolayer until confluency, but do not invade the subendothelial collagen matrix or the underlying support filter. Furthermore, BMEC grown in this manner exhibit biochemical, morphologic, and electrophysiologic properties reflective of the endothelial cells that comprise the blood-brain barrier in vivo. Although the collagen gel acts as an impenetrable barrier to BMEC, and thus ensures the growth of only a single layer of cells, it nevertheless can be infiltrated by monocytes that have been stimulated by a chemotaxin to undergo diapedesis. Thus, growing BMEC on collagen gel-coated Transwells has broad applications for the in vitro study of both blood-brain barrier physiology as well as the mechanisms underlying central nervous system inflammation.     

The role of endothelial dysfunction and oxidative stress in cerebrovascular diseases

Cerebrovascular diseases (CBD) are one of the most dangerous complications of atherosclerosis. The clinical consequences of CBD deeply impact quality of life and the prognosis of patients. Atherosclerosis is the main cause of CBD development. Hypertension, dyslipidemia, diabetes, smoking, obesity, and other risk factors explain the higher CBD incidence in the general population, as they are able to anticipate the clinical expression of atherosclerosis. These risk factors are effectively able to promote endothelial dysfunction which is the premise for the early, clinical expression of atherosclerosis. The mechanisms by which risk factors can influence the occurrence of CBD are different and not fully understood. The inflammatory background of atherosclerosis can explain a great part of it. In particular, the oxidative stress may promote the development of vascular lesions by negatively influencing biochemical cellular processes of the endothelium, thus predisposing the vascular tree to morphological and functional damages. The aim of this narrative review is to evaluate the role of endothelial dysfunction and oxidative stress in CBD development.     

Role of N-WASP in Endothelial Monolayer Formation and Integrity

Endothelial cells (ECs) form a monolayer that serves as a barrier between the blood and the underlying tissue. ECs tightly regulate their cell-cell junctions, controlling the passage of soluble materials and immune cells across the monolayer barrier. We studied the role of N-WASP, a key regulator of Arp2/3 complex and actin assembly, in EC monolayers. We report that N-WASP regulates endothelial monolayer integrity by affecting the organization of cell junctions. Depletion of N-WASP resulted in an increase in transendothelial electrical resistance, a measure of monolayer integrity. N-WASP depletion increased the width of cell-cell junctions and altered the organization of F-actin and VE-cadherin at junctions. N-WASP was not present at cell-cell junctions in monolayers under resting conditions, but it was recruited following treatment with sphingosine-1-phosphate. Taken together, our results reveal a novel role for N-WASP in remodeling EC junctions, which is critical for monolayer integrity and function.     

Blood-brain barrier alterations in bacterial meningitis: Development of an in vitro model and observations on the effects of lipopolysaccharide

Summary To further examine the effects of purifiedHaemophilus influenzae type b lipopolysaccharide (LPS) on blood-brain barrier permeability, we have developed an in vitro model of the BBB. Microvascular endothelial cells were isolated from rat cerebral cortices by enzymatic digestion, dextran centrifugation, and separation on percoll gradients. The cells were determined to be endothelial in origin by positive fluorescent staining for Factor VIII-related antigen and the ability to take up acetylated low density lipoproteins, and their cerebral origin by the formation of junctional complexes in vitro. Cells were seeded onto semipermeable polycarbonate filters and permeability assessed by measuring traversal of radioactive albumin across the monolayer. Treatment of the cells with LPS at concentrations of 1.0μg/ml and 0.1μg/ml for 4 h led to statistically significant increases in albumin permeability of 4.6% (P=0.001) and 5.6% (P<0.001), respectively, without evidence of cell death as assessed by release of lactate dehydrogenase into the media. These results indicate that LPS significantly increases albumin permeability across a monolayer of cerebral microvascular endothelial cells in the absence of host inflammatory cells. Future studies on the effects of LPS on intracellular regulation will determine the mechanisms responsible for these alterations. Supported by a research grant (RO1-AI17904) and a training grant (T32-AI07046) from the National Institute of Allergy and Infectious Diseases, Bethesda, MD. W. Michael Scheld is an established investigator of the American Heart Association.     

The effects of different exercise modes for preventing endothelial dysfunction of arteries and bone loss in ovariectomized rats

[Purpose]

Several epidemiological studies have demonstrated that there are positive correlations between vascular disorders and bone loss in postmenopausal women. The aim of the present study was to examine the effect of different types of exercise (e.g., climbing and swimming) for preventing endothelial dysfunction of arteries and bone loss in ovariectomized rats.

[Methods]

Twenty Sprague-Dawley female rats were randomly divided into three groups: ovariectomy (OVX) plus treatment with vitamin D₃ and nicotine (VDN) (control rats [Con], n = 7), which is an animal model for endothelial dysfunction and bone loss; voluntary climbing resistance exercise with OVX plus VDN (climbing rats [Clim], n = 6), and swimming exercise with OVX plus VDN (swimming rats [Swim], n = 7). The period of exercise training was 8 weeks.

[Results]

The endothelin-1 (ET-1) protein levels were significantly lower in the Clim and Swim groups than in the Con. The endothelial nitric oxide synthase protein levels were significantly higher in the Swim group than in the Con, but they did not differ between the Clim and Con groups. The cortical bone mineral density in the tibia and breaking energy of the femur were significantly higher in the Clim group than in the Con, but this positive effect was not seen in the Swim group.

[Conclusion]

Voluntary climbing exercise decreased arterial ET-1 protein levels and prevented bone loss in a postmenopause-model rat combining OVX and VDN. Conversely, swimming suppressed endothelial dysfunction of the arteries but did not prevent bone loss. Thus, the type of exercise should be cautiously chosen for enhancing vascular function and bone status, especially in females after menopause.     

Significance of neutrophil microparticles in ischaemia‐reperfusion: Pro‐inflammatory effectors of endothelial senescence and vascular dysfunction

Endothelial senescence is an emerging cause of vascular dysfunction. Because microparticles are effectors of endothelial inflammation and vascular injury after ischaemia‐reperfusion, we examined leucocyte‐derived microparticles of spleen origin as possible contributors. Microparticles were generated from primary rat splenocytes by either lipopolysaccharide or phorbol‐myristate‐acetate/calcium ionophore, under conditions mimicking innate and adaptive immune responses. Incubation of primary porcine coronary endothelial cells with either type of microparticles, but not with those from unstimulated splenocytes, leads to a similar threefold raise in senescence‐associated β‐galactosidase activity within 48 hours, indicating accelerated senescence, to endothelial oxidative stress, and a fivefold and threefold increase in p21 and p16 senescence markers after 24 hours. After 12‐hour incubation, the endothelial‐dependent relaxation of coronary artery rings was reduced by 50%, at distinct optimal microparticle concentration. In vitro, microparticles were pro‐thrombotic by up‐regulating the local angiotensin system, by prompting tissue factor activity and a secondary generation of pro‐coagulant endothelial microparticles. They initiated an early pro‐inflammatory response by inducing phosphorylation of NF‐κB, MAP kinases and Akt after 1 hour, and up‐regulated VCAM‐1 and ICAM‐1 at 24 hours. Accordingly, VCAM‐1 and COX‐2 were also up‐regulated in the coronary artery endothelium and eNOS down‐regulated. Lipopolysaccharide specifically favoured the shedding of neutrophil‐ and monocyte‐derived microparticles. A 80% immuno‐depletion of neutrophil microparticles reduced endothelial senescence by 55%, indicating a key role. Altogether, data suggest that microparticles from activated splenocytes prompt early pro‐inflammatory, pro‐coagulant and pro‐senescent responses in endothelial cells through redox‐sensitive pathways. The control of neutrophil shedding could preserve the endothelium at site of ischaemia‐reperfusion–driven inflammation and delay its dysfunction.