| 1. |
- Love, Dominic T., et al.
(författare)
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The role of the myeloperoxidase-derived oxidant hypothiocyanous acid (HOSCN) in the induction of mitochondrial dysfunction in macrophages
- 2020
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Ingår i: Redox Biology. - : Elsevier BV. - 2213-2317. ; 36
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Tidskriftsartikel (refereegranskat)abstract
- A host of chronic inflammatory diseases are accelerated by the formation of the powerful oxidant hypochlorous acid (HOCl) by myeloperoxidase (MPO). In the presence of thiocyanate (SCN-), the production of HOCl by MPO is decreased in favour of the formation of a milder oxidant, hypothiocyanous acid (HOSCN). The role of HOSCN in disease has not been fully elucidated, though there is increasing interest in using SCN- therapeutically in different disease settings. Unlike HOCl, HOSCN can be detoxified by thioredoxin reductase, and reacts selectively with thiols to result in reversible modifications, which could potentially reduce the extent of MPO-induced damage during chronic inflammation. In this study, we show that exposure of macrophages, a key inflammatory cell type, to HOSCN results in the reversible modification of multiple mitochondrial proteins, leading to increased mitochondrial membrane permeability, decreased oxidative phosphorylation and reduced formation of ATP. The increased permeability and reduction in ATP could be reversed by pre-treatment of the macrophages with cyclosporine A, implicating a role for the mitochondrial permeability transition pore. HOSCN also drives cells to utilise fatty acids as an energetic substrate after the inhibition of oxidative phosphorylation. Raman imaging studies highlighted the ability of HOSCN to perturb the electron transport chain of mitochondria and redistribute these organelles within the cell. Taken together, these data provide new insight into the pathways by which HOSCN can induce cytotoxicity and cellular damage, which may have relevance for the development of inflammatory disease, and therapeutic strategies to reduce HOCl-induced damage by supplementation with SCN-.
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| 2. |
- Ninchoji, Takeshi, et al.
(författare)
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eNOS-induced vascular barrier disruption in retinopathy by c-Src activation and tyrosine phosphorylation of VE-cadherin
- 2021
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Ingår i: eLIFE. - : eLife Sciences Publications Ltd. - 2050-084X. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Background:Hypoxia and consequent production of vascular endothelial growth factor A (VEGFA) promote blood vessel leakiness and edema in ocular diseases. Anti-VEGFA therapeutics may aggravate hypoxia; therefore, therapy development is needed.Methods:Oxygen-induced retinopathy was used as a model to test the role of nitric oxide (NO) in pathological neovascularization and vessel permeability. Suppression of NO formation was achieved chemically using L-NMMA, or genetically, in endothelial NO synthase serine to alanine (S1176A) mutant mice.Results:Suppression of NO formation resulted in reduced retinal neoangiogenesis. Remaining vascular tufts exhibited reduced vascular leakage through stabilized endothelial adherens junctions, manifested as reduced phosphorylation of vascular endothelial (VE)-cadherin Y685 in a c-Src-dependent manner. Treatment with a single dose of L-NMMA in established retinopathy restored the vascular barrier and prevented leakage.Conclusions:We conclude that NO destabilizes adheren junctions, resulting in vascular hyperpermeability, by converging with the VEGFA/VEGFR2/c-Src/VE-cadherin pathway.
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| 3. |
- Nitzsche, Anja, 1985-, et al.
(författare)
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Paladin is a phosphoinositide phosphatase regulating endosomal VEGFR2 signalling and angiogenesis
- 2021
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Ingår i: EMBO Reports. - : EMBO Press. - 1469-221X .- 1469-3178. ; 22:2
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Tidskriftsartikel (refereegranskat)abstract
- Cell signalling governs cellular behaviour and is therefore subject to tight spatiotemporal regulation. Signalling output is modulated by specialized cell membranes and vesicles which contain unique combinations of lipids and proteins. The phosphatidylinositol 4,5-bisphosphate (PI(4,5)P-2), an important component of the plasma membrane as well as other subcellular membranes, is involved in multiple processes, including signalling. However, which enzymes control the turnover of non-plasma membrane PI(4,5)P-2, and their impact on cell signalling and function at the organismal level are unknown. Here, we identify Paladin as a vascular PI(4,5)P-2 phosphatase regulating VEGFR2 endosomal signalling and angiogenesis. Paladin is localized to endosomal and Golgi compartments and interacts with vascular endothelial growth factor receptor 2 (VEGFR2) in vitro and in vivo. Loss of Paladin results in increased internalization of VEGFR2, over-activation of extracellular regulated kinase 1/2, and hypersprouting of endothelial cells in the developing retina of mice. These findings suggest that inhibition of Paladin, or other endosomal PI(4,5)P-2 phosphatases, could be exploited to modulate VEGFR2 signalling and angiogenesis, when direct and full inhibition of the receptor is undesirable.
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| 4. |
- Sjöberg, Elin, et al.
(författare)
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Endothelial VEGFR2-PLCγ signaling regulates vascular permeability and antitumor immunity through eNOS/Src
- 2023
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Ingår i: Journal of Clinical Investigation. - : American Society For Clinical Investigation. - 0021-9738 .- 1558-8238. ; 133:20
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Tidskriftsartikel (refereegranskat)abstract
- Endothelial phospholipase C gamma (PLC gamma) is essential for vascular development; however, its role in healthy, mature, or pathological vessels is unexplored. Here, we show that PLC gamma was prominently expressed in vessels of several human cancer forms, notably in renal cell carcinoma (RCC). High PLC gamma expression in clear cell RCC correlated with angiogenic activity and poor prognosis, while low expression correlated with immune cell activation. PLC gamma was induced downstream of vascular endothelial growth factor receptor 2 (VEGFR2) phosphosite Y1173 (pY1173). Heterozygous Vegfr2Y1173F/+ mice or mice lacking endothelial PLC gamma (Plcg1iECKO) exhibited a stabilized endothelial barrier and diminished vascular leakage. Barrier stabilization was accompanied by decreased expression of immunosuppressive cytokines, reduced infiltration of B cells, helper T cells and regulatory T cells, and improved response to chemo-and immunotherapy. Mechanistically, pY1173/PLC gamma signaling induced Ca2+/protein kinase C-dependent activation of endothelial nitric oxide synthase (eNOS), required for tyrosine nitration and activation of Src. Src-induced phosphorylation of VE-cadherin at Y685 was accompanied by disintegration of endothelial junctions. This pY1173/PLC gamma/eNOS/Src pathway was detected in both healthy and tumor vessels in Vegfr2Y1173F/+ mice, which displayed decreased activation of PLC gamma and eNOS and suppressed vascular leakage. Thus, we believe that we have identified a clinically relevant endothelial PLC gamma pathway downstream of VEGFR2 pY1173, which destabilizes the endothelial barrier and results in loss of antitumor immunity.
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