Role of Endothelial Regeneration and Overloading of Enterocytes with Lipids in Capturing of Lipoproteins by Basement Membrane of Rat Aortic Endothelium

Abstract

Atherosclerosis is a complex non-monogenic disease related to endothelial damage in elastic-type arteries and incorrect feeding. Here, using cryodamage of endothelial cells (ECs) of rat abdominal aorta, we examined the role of the EC basement membrane (BM) for re-endothelization endothelial regeneration and its ability to capture low density lipoproteins (LDLs). Regeneration of endothelium induced thickening of the ECBM. Secretion of the BM components occurred in the G2-phase. Multiple regenerations, as well as arterial hypertension and aging, also led to the thickening of the BM. Under these conditions, the speed of re-endothelialization increased. The thick BM captured more LDLs. LDLs formed after overloading of rats with lipids acquired higher affinity to the BM, presumably due to the prolonged transport of chylomicrons through neuraminidase-positive endo-lysosomes. These data provide new molecular and cellular mechanisms of atherogenesis.

The Diffusion Model of Intra-Golgi Transport Has Limited Power

“…For electron microscopy (EM), the samples were prepared as described previously [ 6 , 9 , 56 , 57 , 58 , 59 , 60 ]. All manipulations were carried out at room temperature (~21 °C) unless otherwise stated.…”

Intracellular Membrane Transport in Vascular Endothelial Cells

“…Images ( A , B , F ) are from Figures 142, 170 and 144 (correspondingly) by Volkova et al [ 10 ]. Images ( D , E , H ) are taken from Figure 2A and supplementary images (correspondingly) presented by Sesorova et al [ 16 ]. The image ( G ) is taken from Figure 3E presented by Cottarelli et al [ 17 ].…”

“…COPII buds are not found in quiescent ECs of adult organisms [ 16 ]. They are observed only in regenerating ECs when the EC is in the G2 phase of the cell cycle.…”

“…They are observed only in regenerating ECs when the EC is in the G2 phase of the cell cycle. During this phase, ECs synthesize membrane proteins for their consecutive division [ 4 , 16 , 27 ]. Similarly, in other tissue cells of adult organisms, COPII buds are found only in cells during their G2 phase or in cells forming large secretory granules, namely, in fibroblasts, in pancreas, and in goblet cells [ 28 , 29 , 30 , 31 ].…”

“…For instance, in the liver, there are no secretory granules and therefore very low density lipoproteins (VLDL) are transported towards the Disses space in Golgi-to-PM carriers. In enterocytes of the whole small intestine, ER exit sites are not found [ 4 , 16 , 27 , 32 ]. After inhibition of COPII, chylomicrons are still formed in the smooth ER [ 32 ].…”