Dataset Information

Endothelial Immune Activation by Medin: Potential Role in Cerebrovascular Disease and Reversal by Monosialoganglioside-Containing Nanoliposomes.

ABSTRACT: Background The function of medin, one of the most common human amyloid proteins that accumulates in the vasculature with aging, remains unknown. We aim to probe medin's role in cerebrovascular disease by comparing cerebral arterial medin content between cognitively normal and vascular dementia (VaD) patients and studying its effects on endothelial cell (EC) immune activation and neuroinflammation. We also tested whether monosialoganglioside-containing nanoliposomes could reverse medin's adverse effects. Methods and Results Cerebral artery medin and astrocyte activation were measured and compared between VaD and cognitively normal elderly brain donors. ECs were exposed to physiologic dose of medin (5 ?mol/L), and viability and immune activation (interleukin-8, interleukin-6, intercellular adhesion molecule-1, and plasminogen activator inhibitor-1) were measured without or with monosialoganglioside-containing nanoliposomes (300 ?g/mL). Astrocytes were exposed to vehicle, medin, medin-treated ECs, or their conditioned media, and interleukin-8 production was compared. Cerebral collateral arterial and parenchymal arteriole medin, white matter lesion scores, and astrocyte activation were higher in VaD versus cognitively normal donors. Medin induced EC immune activation (increased interleukin-8, interleukin-6, intercellular adhesion molecule-1, and plasminogen activator inhibitor-1) and reduced EC viability, which were reversed by monosialoganglioside-containing nanoliposomes. Interleukin-8 production was augmented when astrocytes were exposed to medin-treated ECs or their conditioned media. Conclusions Cerebral arterial medin is higher in VaD compared with cognitively normal patients. Medin induces EC immune activation that modulates astrocyte activation, and its effects are reversed by monosialoganglioside-containing nanoliposomes. Medin is a candidate novel risk factor for aging-related cerebrovascular disease and VaD.

SUBMITTER: Karamanova N

PROVIDER: S-EPMC7033828 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature

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Endothelial Immune Activation by Medin: Potential Role in Cerebrovascular Disease and Reversal by Monosialoganglioside-Containing Nanoliposomes.

Karamanova Nina N Truran Seth S Serrano Geidy E GE Beach Thomas G TG Madine Jillian J Weissig Volkmar V Davies Hannah A HA Veldhuizen Jaimeson J Nikkhah Mehdi M Hansen Michael M Zhang Weiyang W D'Souza Karen K Franco Daniel A DA Migrino Raymond Q RQ

Journal of the American Heart Association 20200113 2

Background The function of medin, one of the most common human amyloid proteins that accumulates in the vasculature with aging, remains unknown. We aim to probe medin's role in cerebrovascular disease by comparing cerebral arterial medin content between cognitively normal and vascular dementia (VaD) patients and studying its effects on endothelial cell (EC) immune activation and neuroinflammation. We also tested whether monosialoganglioside-containing nanoliposomes could reverse medin's adverse ...[more]

PMID: 31928157

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Project description:Medin, a 50-amino-acid cleavage product of the milk fat globule-EGF factor 8 protein, is one of the most common forms of localized amyloid found in the vasculature of individuals older than 50 years. Medin induces endothelial dysfunction and vascular inflammation, yet despite its prevalence in the human aorta and multiple arterial beds, little is known about the nature of its pathology. Medin oligomers have been implicated in the pathology of aortic aneurysm, aortic dissection, and more recently, vascular dementia. Recent in vitro biomechanical measurements found increased oligomer levels in aneurysm patients with altered aortic wall integrity. Our results suggest an oligomer-mediated toxicity mechanism for medin pathology. Using lipid bilayer electrophysiology, we show that medin oligomers induce ionic membrane permeability by pore formation. Pore activity was primarily observed for preaggregated medin species from the growth-phase and rarely for lag-phase species. Atomic force microscopy (AFM) imaging of medin aggregates at different stages of aggregation revealed the gradual formation of flat domains resembling the morphology of supported lipid bilayers. Transmission electron microscopy images showed the coexistence of compact oligomers, largely consistent with the AFM data, and larger protofibrillar structures. Circular dichroism spectroscopy revealed the presence of largely disordered species and suggested the presence of ?-sheets. This observation and the significantly lower thioflavin T fluorescence emitted by medin aggregates compared to amyloid-? fibrils, along with the absence of amyloid fibers in the AFM and transmission electron microscopy images, suggest that medin aggregation into pores follows a nonamyloidogenic pathway. In silico modeling by molecular dynamics simulations provides atomic-level structural detail of medin pores with the CNpNC barrel topology and diameters comparable to values estimated from experimental pore conductances.

Project description:AimsMedin is a common amyloidogenic protein in humans that accumulates in arteries with advanced age and has been implicated in vascular degeneration. Medin's effect on endothelial function remains unknown. The aims are to assess medin's effects on human arteriole endothelial function and identify potential mechanisms underlying medin-induced vascular injury.Methods and resultsEx vivo human adipose and leptomeningeal arterioles were exposed (1 h) to medin (0.1, 1, or 5 µM) without or with FPS-ZM1 [100 µM, receptor for advanced glycation endproducts (RAGE)-specific inhibitor] and endothelium-dependent function (acetylcholine dilator response) and endothelium-independent function (dilator response to nitric oxide donor diethylenetriamine NONOate) were compared with baseline control. Human umbilical vein endothelial cells were exposed to medin without or with FPS-ZM1 and oxidative and nitrative stress, cell viability, and pro-inflammatory signaling measures were obtained. Medin caused impaired endothelial function (vs. baseline response: -45.2 ± 5.1 and -35.8 ± 7.9% in adipose and leptomeningeal arterioles, respectively, each P < 0.05). Dilator response to NONOate was not significantly changed. Medin decreased arteriole and endothelial cell nitric oxide production, increased superoxide production, reduced endothelial cell viability, proliferation, and migration. Medin increased gene and protein expression of interleukin-6 and interleukin-8 via activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB). Medin-induced endothelial dysfunction and oxidative stress were reversed by antioxidant polyethylene glycol superoxide dismutase and by RAGE inhibitor FPS-ZM1.ConclusionsMedin causes human microvascular endothelial dysfunction through oxidative and nitrative stress and promotes pro-inflammatory signaling in endothelial cells. These effects appear to be mediated via RAGE. The findings represent a potential novel mechanism of vascular injury.

Dataset Information

Endothelial Immune Activation by Medin: Potential Role in Cerebrovascular Disease and Reversal by Monosialoganglioside-Containing Nanoliposomes.

Publications

Endothelial Immune Activation by Medin: Potential Role in Cerebrovascular Disease and Reversal by Monosialoganglioside-Containing Nanoliposomes.

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