Age-related changes in scavenger receptor-mediated endocytosis in rat liver sinusoidal endothelial cells.
Liver sinusoidal endothelial cells (LSECs) play an essential role in systemic waste clearance by effective endocytosis of blood-borne waste macromolecules. We aimed to study LSECs' scavenger function during aging, and whether age-related morphological changes (eg, defenestration) affect this function, in F344/BN F1 rats. Endocytosis of the scavenger receptor ligand formaldehyde-treated serum albumin was significantly reduced in LSECs from old rats. Ligand degradation, LSEC protein expression of the major scavenger receptors for formaldehyde-treated serum albumin endocytosis, stabilin-1 and stabilin-2, and their staining patterns along liver sinusoids, was similar at young and old age, suggesting that other parts of the endocytic machinery are affected by aging. Formaldehyde-treated serum albumin uptake per cell, and cell porosity evaluated by electron microscopy, was not correlated, indicating that LSEC defenestration is not linked to impaired endocytosis. We report a significantly reduced LSEC endocytic capacity at old age, which may be especially important in situations with increased circulatory waste loads.
Simon-Santamaria
Jaione
J
Department of Medical Biology, University of Tromsø, NO-9037 Tromsø, Norway.
Malovic
Ivana
I
Warren
Alessandra
A
Oteiza
Ana
A
Le Couteur
David
D
Smedsrød
Bård
B
McCourt
Peter
P
Sørensen
Karen Kristine
KK
D000375:Aging / Q000378:metabolism*; D000818:Animals; D015816:Cell Adhesion Molecules, Neuronal / Q000378:metabolism; D002478:Cells, Cultured; D004705:Endocytosis; D042783:Endothelial Cells / Q000378:metabolism*; D005557:Formaldehyde / Q000378:metabolism; D008099:Liver / Q000166:cytology* / Q000648:ultrastructure; D008297:Male; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D051381:Rats; D011916:Rats, Inbred F344; D011956:Receptors, Cell Surface / Q000378:metabolism; D012710:Serum Albumin, Bovine / Q000378:metabolism
D015816:Cell Adhesion Molecules, Neuronal; D011956:Receptors, Cell Surface; C486732:Stab1 protein, mouse; C486733:Stab2 protein, mouse; D005557:Formaldehyde; D012710:Serum Albumin, Bovine