1. The role of plasmalemma vesicle-associated protein in pathological breakdown of blood-brain and blood-retinal barriers : potential novel therapeutic target for cerebral edema and diabetic macular edemaEsmeralda K. Bosma, Cornelis J. F. van Noorden, Reinier O. Schlingemann, Ingeborg Klaassen, 2018, review article Abstract: Breakdown of the blood–brain barrier (BBB) or inner blood–retinal barrier (BRB), induced by pathologically elevated levels of vascular endothelial growth factor (VEGF) or other mediators, can lead to vasogenic edema and significant clinical problems such as neuronal morbidity and mortality, or vision loss. Restoration of the barrier function with corticosteroids in the brain, or by blocking VEGF in the eye are currently the predominant treatment options for brain edema and diabetic macular edema, respectively. However, corticosteroids have side effects, and VEGF has important neuroprotective, vascular protective and wound healing functions, implying that long-term anti-VEGF therapy may also induce adverse effects. We postulate that targeting downstream effector proteins of VEGF and other mediators that are directly involved in the regulation of BBB and BRB integrity provide more attractive and safer treatment options for vasogenic cerebral edema and diabetic macular edema. The endothelial cell-specific protein plasmalemma vesicle-associated protein (PLVAP), a protein associated with trans-endothelial transport, emerges as candidate for this approach. PLVAP is expressed in a subset of endothelial cells throughout the body where it forms the diaphragms of caveolae, fenestrae and trans-endothelial channels. However, PLVAP expression in brain and eye barrier endothelia only occurs in pathological conditions associated with a compromised barrier function such as cancer, ischemic stroke and diabetic retinopathy. Here, we discuss the current understanding of PLVAP as a structural component of endothelial cells and regulator of vascular permeability in health and central nervous system disease. Besides providing a perspective on PLVAP identification, structure and function, and the regulatory processes involved, we also explore its potential as a novel therapeutic target for vasogenic cerebral edema and retinal macular edema.
Keywords: plasmalemma vesicle-associated protein, blood-brain barrier, blood-retinal barrier, cerebral edema, diabetic macular edema
Published in DiRROS: 06.08.2024; Views: 78; Downloads: 51
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2. Quantitative assessment of the apical and basolateral membrane expression of VEGFR2 and NRP2 in VEGF-A-stimulated cultured human umbilical vein endothelial cellsEsmeralda K. Bosma, Shahan Darwesh, Jia Y. Zheng, Cornelis J. F. van Noorden, Reinier O. Schlingemann, Ingeborg Klaassen, 2022, original scientific article Abstract: Endothelial cells (ECs) form a precisely regulated polarized monolayer in capillary walls. Vascular endothelial growth factor-A (VEGF-A) induces endothelial hyperpermeability, and VEGF-A applied to the basolateral side, but not the apical side, has been shown to be a strong barrier disruptor in blood–retinal barrier ECs. We show here that VEGF-A presented to the basolateral side of human umbilical vein ECs (HUVECs) induces higher permeability than apical stimulation, which is similar to results obtained with bovine retinal ECs. We investigated with immunocytochemistry and confocal imaging the distribution of VEGF receptor-2 (VEGFR2) and neuropilin-2 (NRP2) in perinuclear apical and basolateral membrane domains. Orthogonal z-sections of cultured HUVECs were obtained, and the fluorescence intensity at the apical and basolateral membrane compartments was measured. We found that VEGFR2 and NRP2 are evenly distributed throughout perinuclear apical and basolateral membrane compartments in unstimulated HUVECs grown on Transwell inserts, whereas basolateral VEGF-A stimulation induces a shift toward basolateral VEGFR2 and NRP2 localization. When HUVECs were grown on coverslips, the distribution of VEGFR2 and NRP2 across the perinuclear apical and basolateral membrane domains was different. Our findings demonstrate that HUVECs dynamically regulate VEGFR2 and NRP2 localization on membrane microdomains, depending on growth conditions and the polarity of VEGF-A stimulation.
Keywords: endotelijske celice, EGF, celična biologija
Published in DiRROS: 17.07.2024; Views: 116; Downloads: 105
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3. Diferential roles of eNOS in late efects ofVEGF‑A on hyperpermeability in diferent types of endothelial cellsEsmeralda K. Bosma, Shahan Darwesh, Yasmin I. Habani, Maxime Cammeraat, Paola Serrano Martinez, Mathilda E. van Breest Smallenburg, JiaY. Zheng, Ilse M.C. Vogels, Cornelis J. F. van Noorden, Reinier O. Schlingemann, Ingeborg Klaassen, 2023, original scientific article Abstract: Vascular endothelial growth factor (VEGF)-A induces endothelial hyperpermeability, but the molecular
pathways remain incompletely understood. Endothelial nitric oxide synthase (eNOS) regulates acute
efects of VEGF-A on permeability of endothelial cells (ECs), but it remains unknown whether and how
eNOS regulates late efects of VEGF-A-induced hyperpermeability. Here we show that VEGF-A induces
hyperpermeability via eNOS-dependent and eNOS-independent mechanisms at 2 days after VEGF-A
stimulation. Silencing of expression of the eNOS gene (NOS3) reduced VEGF-A-induced permeability
for dextran (70 kDa) and 766 Da-tracer in human dermal microvascular ECs (HDMVECs), but not in
human retinal microvascular ECs (HRECs) and human umbilical vein ECs (HUVECs). However, silencing
of NOS3 expression in HRECs increased permeability to dextran, BSA and 766 Da-tracer in the absence
of VEGF-A stimulation, suggesting a barrier-protective function of eNOS. We also investigated how
silencing of NOS3 expression regulates the expression of permeability-related transcripts, and
found that NOS3 silencing downregulates the expression of PLVAP, a molecule associated with
trans-endothelial transport via caveolae, in HDMVECs and HUVECs, but not in HRECs. Our fndings
underscore the complexity of VEGF-A-induced permeability pathways in ECs and the role of eNOS
therein, and demonstrate that diferent pathways are activated depending on the EC phenotype.
Keywords: endocytosis, RNAi, hyperpermeability
Published in DiRROS: 15.07.2024; Views: 156; Downloads: 117
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