Docosahexaenoic Acid Reduces Amyloid-β Induced Toxicity in Cells of the Neurovascular Unit

Abstract

Alzheimer's disease (AD) is characterized by the accumulation of amyloid-β peptides (Aβ) as perivascular deposits and senile plaques in the brain. The intake of the polyunsaturated fatty acid docosahexaenoic acid (DHA) has been associated with decreased amyloid deposition and reduced risk in AD in several epidemiological trials; however the exact underlying molecular mechanism remains to be elucidated. The aim of the study was to test whether DHA can exert a direct protective effect on the elements of the neurovascular unit, such as neurons, glial cells, brain endothelial cells, and pericytes, treated with Aβ42 (15 μM). A dose-dependent high cellular toxicity was found in viability assays in all cell types and on acute hippocampal slices after treatment with Aβ42 small oligomers prepared in situ from an isopeptide precursor. The cell morphology also changed dramatically in all cell types. In brain endothelial cells, damaged barrier function and increased para- and transcellular permeability were observed after peptide treatment. The production of reactive oxygen species was elevated in pericytes and endothelial and glial cells. DHA (30 μM) significantly decreased the Aβ42-induced toxic effects in all cell types measured by viability assays, and protected the barrier integrity and functions of brain endothelial cells. DHA also decreased the elevated rhodamine 123 accumulation in brain endothelial cells pre-treated with Aβ42 indicating an effect on efflux pump activity. These results indicate for the first time that DHA can protect not only neurons but also the other elements of the neurovascular unit from the toxic effects of Aβ42 and this effect may be beneficial in AD.

A versatile lab-on-a-chip tool for modeling biological barriers

“…Samples from the luminal and abluminal compartments were collected. Permeability measurements were also performed on Transwell inserts using 500 l volumes with marker molecules for the upper and 1500 l for the lower compartments [24,25]. During the experiments inserts were kept in 12-well plates (Corning, USA) and inserts were moved after 20, 40 and 60 min to the next well of the plate.…”

“…Triple primary co-culture BBB model was assessed as shown in Fig. 2 and described previously [15,24,29].…”

“…Brain microvascular endothelial cell line hCMEC/D3 [9] and primary rat brain endothelial cells [23][24][25] were used as models of the blood-brain barrier on the chip. Cultures of hCMEC/D3 cells (≤passage number 35) were grown in MCDB 131 medium (Pan Biotech) supplemented with 5% FBS, GlutaMAX (100×, Life Technologies, USA), lipid supplement (100×, Life Technologies, USA), 10 g/ml ascorbic acid, 550 nM hydrocortisone, 100 g/ml heparin, 1 ng/ml basic fibroblast growth factor (bFGF, Roche, USA), insulin (2.5 g/ml), transferrin (2.5 g/ml), sodium selenite (2.5 ng/ml) and 50 g/ml gentamicin.…”

“…Permeability of Evans blue-labeled albumin (EBA, MW: 67 kDa) was also tested across cell monolayers as previously described [24,25]. For the assay cell culture medium was changed in the lower compartment of the chip to 500 l Ringer-Hepes solution (118 mM NaCl, 4.8 mM KCl, 2.5 mM CaCl 2 , 1.2 mM MgSO 4 , 5.5 mM d-glucose, 10 mM Hepes, pH 7.4).…”

Role of GDF15 in radiosensitivity of breast cancer cells

“…The RTCA-SP instrument (ACEA Biosciences, US) measures impedance continuously and is automatized to non-invasively quantify adherent cell proliferation and viability in realtime. This method has been effectively utilized previously to quantify and measure the number, adherence, growth, and viability of cells [20][21][22][23][24]. 50 µL of cell culture medium was added to each well of the microtiter E-plates for impedance background measurements, and then 50 µL cell suspensions were dispensed at the density of 10 3 cells/well.…”