Critical role of autophagy regulator Beclin1 in endothelial cell inflammation and barrier disruption

Leonard, Antony; Millar, Michelle Warren; Slavin, Spencer; Bijli, Kaiser M.; Santos, Dawling A. Dionisio; Dean, David A.; Fazal, Fabeha; Rahman, Arshad

doi:10.1016/j.cellsig.2019.04.013

Cited by 27 publications

(34 citation statements)

References 57 publications

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“…Despite this, ATG7 knockdown inhibited thrombin-induced nuclear activation of RelA/p65, as assessed by DNA binding activity of RelA/p65 in the nucleus. A similar observation was made upon Beclin1 silencing in our previous work 39 . The normal liberation from IκBα and activating phosphorylation, but diminished DNA binding activity of RelA/p65 points to a possible defect in the translocation of the released RelA/p65 to the nucleus.…”

Section: Discussionsupporting

confidence: 88%

“…We have recently shown that silencing of another autophagy protein Beclin1 leads to an impaired translocation of RelA/p65 to the nucleus upon thrombin challenge 39 . This raises possibility that the impaired DNA binding in ATG7 deficient cells may be attributed to disruption of RelA/p65 nuclear translocation.…”

Section: Atg7 Mediates Thrombin-induced Inflammation Via Nf-κb Activamentioning

confidence: 99%

“…Human pulmonary artery endothelial cells (HPAEC) were purchased from Lonza (Walkersville, MD). They were cultured in 0.1% gelatin-coated flasks as described previously 39 in endothelial basal medium 2 (EBM2) containing 10% FBS and bullet kit additives (BioWhittaker, Walkersville, MD). Experiments were performed with HPAEC which were between passages 4 and 7.…”

Section: Reagents Human α-Thrombin Was Purchased From Enzyme Researcmentioning

confidence: 99%

“…The cells were then washed two times with PBS and allowed to grow to confluency in EBM2 medium containing 10% FBS. 39 .…”

Section: Reagents Human α-Thrombin Was Purchased From Enzyme Researcmentioning

confidence: 99%

“…Equal amount of nuclear proteins was analyzed for RelA/p65 nuclear translocation by immunoblotting. The DNA binding activity of RelA/p65 was determined using an ELISA-based DNA binding assay kit (Cayman Chemical, Ann Arbor, MI) as described 39 .…”

Section: Elisamentioning

confidence: 99%

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Autophagy protein ATG7 is a critical regulator of endothelial cell inflammation and permeability

Shadab

Millar

Slavin

et al. 2020

Sci Rep

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Endothelial cell (EC) inflammation and permeability are critical pathogenic mechanisms in many inflammatory conditions including acute lung injury. In this study, we investigated the role of ATG7, an essential autophagy regulator with no autophagy-unrelated functions, in the mechanism of EC inflammation and permeability. Knockdown of ATG7 using si-RNA significantly attenuated thrombin-induced expression of proinflammatory molecules such as IL-6, MCP-1, ICAM-1 and VCAM-1. Mechanistic study implicated reduced NF-κB activity in the inhibition of EC inflammation in ATG7silenced cells. Moreover, depletion of ATG7 markedly reduced the binding of RelA/p65 to DNA in the nucleus. Surprisingly, the thrombin-induced degradation of IκBα in the cytosol was not affected in ATG7-depleted cells, suggesting a defect in the translocation of released RelA/p65 to the nucleus in these cells. This is likely due to suppression of thrombin-induced phosphorylation and thereby inactivation of Cofilin1, an actin-depolymerizing protein, in ATG7-depleted cells. Actin stress fiber dynamics are required for thrombin-induced translocation of RelA/p65 to the nucleus, and indeed our results showed that ATG7 silencing inhibited this response via inactivation of Cofilin1. ATG7 silencing also reduced thrombin-mediated EC permeability by inhibiting the disassembly of VE-cadherin at adherens junctions. Together, these data uncover a novel function of ATG7 in mediating EC inflammation and permeability, and provide a mechanistic basis for the linkage between autophagy and EC dysfunction. Endothelial cell (EC) inflammation and permeability represent two major pathogenic features of many inflammatory conditions including acute lung injury (ALI) 1-3. ECs form the lining of the blood vessels of many organs such as the lung, heart, brain, kidney, and liver etc. Thus, ECs play an important role as a gate-keeper, preserving vascular integrity and providing a natural barrier to circulating blood, together maintaining homeostasis 4,5. Previous studies on EC inflammation and barrier function have shown that vascular EC exposed to bacterial, chemical, and mechanical insults secrete inflammatory and chemotactic molecules, and demonstrate loss of barrier integrity 6. Among the major causes for the exhibition of such inflammation and barrier disruption include activation of the transcription factor NF-κB and disassembly of adherens junctions (AJs) 7,8. NF-κB is a ubiquitously expressed family of transcription factors which play important roles in various processes including inflammation, cell proliferation, differentiation, and survival 9,10. The NF-κB family is comprised of five members: Rel (c-Rel), Rel A (p65), Rel B, NF-κB1 (p105/p50), and NF-κB2 (p100/p52) 11,12. In inactive conditions NF-κB remains in the cytoplasm while bound to its inhibitory protein IκBα 9. During an inflammatory response, IκBα undergoes phosphorylation at Ser32 and Ser36 leading to its proteasome-mediated degradation and subsequent release of NF-κB (predominantly RelA/p65 homodimer in EC) 1...

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Section: Discussionsupporting

confidence: 88%

Section: Atg7 Mediates Thrombin-induced Inflammation Via Nf-κb Activamentioning

confidence: 99%

Section: Reagents Human α-Thrombin Was Purchased From Enzyme Researcmentioning

confidence: 99%

“…The cells were then washed two times with PBS and allowed to grow to confluency in EBM2 medium containing 10% FBS. 39 .…”

Section: Reagents Human α-Thrombin Was Purchased From Enzyme Researcmentioning

confidence: 99%

Section: Elisamentioning

confidence: 99%

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Autophagy protein ATG7 is a critical regulator of endothelial cell inflammation and permeability

Shadab

Millar

Slavin

et al. 2020

Sci Rep

Self Cite

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show abstract

Autophagy in the vasculature

Steenput

Neutel

Hermans

et al. 2022

Autophagy in Health and Disease

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Trimethylamine-N-oxide (TMAO) promotes balloon injury-induced neointimal hyperplasia via upregulating Beclin1 and impairing autophagic flux

Hong¹,

Que²,

Zhong³

et al. 2022

Biomedicine & Pharmacotherapy

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Critical role of autophagy regulator Beclin1 in endothelial cell inflammation and barrier disruption

Cited by 27 publications

References 57 publications

Autophagy protein ATG7 is a critical regulator of endothelial cell inflammation and permeability

Autophagy protein ATG7 is a critical regulator of endothelial cell inflammation and permeability

Autophagy in the vasculature

Trimethylamine-N-oxide (TMAO) promotes balloon injury-induced neointimal hyperplasia via upregulating Beclin1 and impairing autophagic flux

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