Rapamycin modulates the eNOS vs. shear stress relationship

Cheng, Caroline; Tempel, Dennie; Oostlander, A.E.; Helderman, Frank; Gijsen, Frank; Wentzel, Jolanda J.; Haperen, Rien van; Haitsma, David B.; Serruys, Patrick W.; Steen, A.F.W. van der; Crom, Rini de; Krams, Rob

doi:10.1093/cvr/cvm103

Cited by 62 publications

(55 citation statements)

References 16 publications

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“…qPCR analysis was performed for transcripts of mouse FRG, FGD1 through FGD6, endothelial nitric oxide synthase, p21 CIP1 , and CD31, as well as for human VEGF receptor (VEGFR) 1/2, Notch1/4, DLL4, jagged1, ephrin B2/B4, NRP1/2, p53, and Hey1. Target mRNA expression levels are reported relative to the housekeeping genes, hypoxanthine guanine phosphoribosyl transferase (Hprt1) in murine samples and ␤-actin in the human samples, as previously described 14 (All primer sequences are provided in Tables I and II in the online-only Data Supplement). For Western blot analysis, samples were lysed in NP40 buffer and analyzed on a 1.5% SDS-PAGE gel, followed by Western blotting with 1:1000 rat anti-p21 CIP1 and anti-p53 antibody (Abcam, Cambridge, UK); 1:500 rabbit anti-cdc42, anti-Rac1, and anti-RhoA antibody (Abcam, Cambridge, UK); and 1:500 mouse anti-FGD5 antibody (Bioscience, Temse, Belgium) for protein detection.…”

Section: Qpcr and Western Blot Analysismentioning

confidence: 99%

Endothelial Cell–Specific FGD5 Involvement in Vascular Pruning Defines Neovessel Fate in Mice

et al. 2012

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Background-New vessel formation contributes to organ development during embryogenesis and tissue repair in response to mechanical damage, inflammation, and ischemia in adult organisms. Early angiogenesis includes formation of an excessive primitive network that needs to be reorganized into a secondary vascular network with higher hierarchical structure. Vascular pruning, the removal of aberrant neovessels by apoptosis, is a vital step in this process. Although multiple molecular pathways for early angiogenesis have been identified, little is known about the genetic regulators of secondary network development. Methods and Results-Using a transcriptomics approach, we identified a new endothelial specific gene named FYVE, RhoGEF, and PH domain-containing 5 (FGD5) that plays a crucial role in vascular pruning. Loss-and gain-of-function studies demonstrate that FGD5 inhibits neovascularization, indicated by in vitro tube-formation, aortic-ring, and coated-bead assays and by in vivo coated-bead plug assays and studies in the murine retina model. FGD5 promotes apoptosis-induced vaso-obliteration via induction of the hey1-p53 pathway by direct binding and activation of cdc42. Indeed, FGD5 correlates with apoptosis in endothelial cells during vascular remodeling and was linked to rising p21 Key Words: angiogenesis-inducing agents Ⅲ apoptosis Ⅲ endothelium Ⅲ FGD5 Ⅲ models, animal V ascularization during development and regeneration plays a vital role in adult disease progression, including tumor growth and metastasis, arthritis, diabetic retinopathy, and cardiovascular disease. Vascular growth in both development and disease consists of a strictly orchestrated, multistep process that requires integrated activation of several molecular pathways. During early vascular growth, a dense primary vascular network without functional arterial and venous distinction is formed in response to low-oxygen conditions. This primitive system, consisting of small capillaries, is relatively unstable, with tip and stalk cell vessel structures expanding and collapsing at a high rate. Transition of this primary network into a stable secondary vasculature with a defined arterial/venous hierarchy of larger vessels that branch into a restricted capillary field requires intensive vascular remodeling, a late angiogenic process that includes neovessel stabilization and pruning of redundant vessel structures. 1,2 Editorial see p 3063 Clinical Perspective on p 3158The molecular regulation by angiogenic factors such as vascular endothelial growth factor (VEGF)-A and fibroblast growth factor that promote growth of the primary vasculature has been studied extensively. In contrast, the key molecular pathways that regulate the reorganization of this early network into the more mature secondary vascular structure are still largely undefined. For the process of vascular pruning, vaso-obliteration by apoptosis induced by hyperoxia has been described, 3 but little is known about the molecular regulation of this important aspect in vascular remodeling that dete...

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Section: Qpcr and Western Blot Analysismentioning

confidence: 99%

Endothelial Cell–Specific FGD5 Involvement in Vascular Pruning Defines Neovessel Fate in Mice

et al. 2012

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“…Thus, our results indicate that rapamycin acts as a vasodilator, in agreement with prior reports. 63,64 A link between the inhibition of mTOR and the activation of eNOS had been suggested by studies showing that Akt, which phosphorylates eNOS and increases NO production, 65 can be activated by rapamycin treatment, 66,67 and conversely, that activation of mTOR results in Akt inhibition. 66,68 Restoration of vascular density in AD mice required NO synthase activity, suggesting that mTOR has a critical role in the inhibition of NO release in brain vascular endothelium during the progression of AD-like disease in mice ( Figure 5).…”

Section: Discussionmentioning

confidence: 99%

Chronic Rapamycin Restores Brain Vascular Integrity and Function Through NO Synthase Activation and Improves Memory in Symptomatic Mice Modeling Alzheimer’s Disease

Lin¹,

Zheng

Halloran

et al. 2013

J Cereb Blood Flow Metab

181

204

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Vascular pathology is a major feature of Alzheimer's disease (AD) and other dementias. We recently showed that chronic administration of the target-of-rapamycin (TOR) inhibitor rapamycin, which extends lifespan and delays aging, halts the progression of AD-like disease in transgenic human (h)APP mice modeling AD when administered before disease onset. Here we demonstrate that chronic reduction of TOR activity by rapamycin treatment started after disease onset restored cerebral blood flow (CBF) and brain vascular density, reduced cerebral amyloid angiopathy and microhemorrhages, decreased amyloid burden, and improved cognitive function in symptomatic hAPP (AD) mice. Like acetylcholine (ACh), a potent vasodilator, acute rapamycin treatment induced the phosphorylation of endothelial nitric oxide (NO) synthase (eNOS) and NO release in brain endothelium. Administration of the NOS inhibitor L-NG-Nitroarginine methyl ester reversed vasodilation as well as the protective effects of rapamycin on CBF and vasculature integrity, indicating that rapamycin preserves vascular density and CBF in AD mouse brains through NOS activation. Taken together, our data suggest that chronic reduction of TOR activity by rapamycin blocked the progression of AD-like cognitive and histopathological deficits by preserving brain vascular integrity and function. Drugs that inhibit the TOR pathway may have promise as a therapy for AD and possibly for vascular dementias.

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“…Reverse transcription of macrophage RNA was performed at 42°C, using oligo(dT) [12][13][14][15][16][17][18] and Superscript II Reverse Transcriptase (Invitrogen). TaqMan gene expression assays (Applied Biosystems, Foster City, CA) for IL-6, MCP1, Rantes, and TNFa were then performed on an ABI Prism 7300 sequence detector system (Applied Biosystems) in 25-L reaction volumes containing 13 Universal PCR Master Mix (Applied Biosystems).…”

Section: Real-time Quantitative Rt-pcrmentioning

confidence: 99%

“…9,10 Third, everolimus prevents lipid accumulation in macrophages and SMCs due to inhibition of endogenous cholesterol synthesis, 11 downregulation of low-density lipoprotein (LDL) receptors and scavenger receptors, 12,13 as well as upregulation of cholesterol efflux genes. 12,13 Other beneficial effects include upregulation of endothelial nitric oxide synthase (eNOS) in low shear regions, which are susceptible to atherosclerosis, 14 and inhibition of hyaluronan deposition by SMCs, 15 a product that stimulates monocyte adhesion to the extracellular matrix. Studies in different animal models confirm the general notion that everolimus strongly inhibits plaque progression.…”

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confidence: 99%

Everolimus Triggers Cytokine Release by Macrophages

Martinet

Verheye²,

Meyer³

et al. 2012

ATVB

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Objective-Stent-based delivery of the mammalian target of rapamycin (mTOR) inhibitor everolimus is a promising strategy for the treatment of coronary artery disease. We studied potential adverse effects associated with mTOR inhibition. Methods and Results-Macrophages in culture were either treated with everolimus or starved to inhibit mTOR. Everolimus led to inhibition of protein translation, activation of p38 MAPK, and the release of proinflammatory cytokines (eg, IL-6, TNFa) and chemokines (eg, MCP1, Rantes) before induction of autophagic death. These effects were also observed with rapamycin, but not after starvation. Everolimus-induced cytokine release was similar in macrophages lacking the essential autophagy gene Atg7 but was inhibited when macrophages were cotreated with p38 MAPK inhibitor SB202190 or the glucocorticoid clobetasol. Combined stent-based delivery of clobetasol and everolimus in rabbit plaques downregulated TNFa expression as compared with everolimus-treated plaques but did not affect the ability of everolimus to induce macrophage clearance. Conclusion-mTOR inhibition by everolimus triggers cytokine release in macrophages through inhibition of protein translation and p38 activation. These findings provide a rationale for combined local treatment of atherosclerotic plaques with everolimus and an anti-inflammatory agent. (Arterioscler Thromb Vasc Biol . 2012;32:1228-1235 .)

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Rapamycin modulates the eNOS vs. shear stress relationship

Abstract: Rapamycin is associated with high eNOS in low shear regions, i.e. in atherogenic regions, protecting these regions against atherosclerosis, and is associated with a reduction of eNOS at high shear stress affecting vasomotion in these regions.

Cited by 62 publications

References 16 publications

Endothelial Cell–Specific FGD5 Involvement in Vascular Pruning Defines Neovessel Fate in Mice

Endothelial Cell–Specific FGD5 Involvement in Vascular Pruning Defines Neovessel Fate in Mice

Chronic Rapamycin Restores Brain Vascular Integrity and Function Through NO Synthase Activation and Improves Memory in Symptomatic Mice Modeling Alzheimer’s Disease

Everolimus Triggers Cytokine Release by Macrophages

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