The low molecular weight fraction of commercial human serum albumin induces acetylation of α-tubulin and reduces transcytosis in retinal endothelial cells.
It has long been appreciated that the microtubule network plays a critical role in endothelial cell function. Chemical inhibition of tubulin polymerization has been shown to drastically increases endothelial permeability via interactions with the actin cytoskeleton. Conversely, stabilization of microtubules significantly decreases vascular permeability. The purpose of this investigation was to determine if the low molecular weight fraction of commercial 5% human serum albumin (LMWF5A) alters endothelial cell cytoskeletal dynamics and function. To investigate this, human retinal endothelial cells (HREC) were treated with LMWF5A and the acetylation of α-tubulin was determined by immunofluorescent staining and immunoblotting. In addition, permeability assays were performed to evaluate functional changes. We found that HREC treated with LMWF5A exhibit a rapid increase in the amount and distribution of acetylated α-tubulin. This was accompanied by a reduction in macromolecular permeability. Calcium depletion and inhibition of PI3-kinase reduced LMWF5A-induced acetylation while p38 MAPK inhibition potentiated this effect. These findings suggest that LMWF5A mediates changes in the microtubule network and reduces transcytosis in HREC.
Swedish Medical Center, Trauma Research Department, 501 E. Hampden Ave, Englewood, CO 80113, USA; St. Anthony Hospital, Trauma Research Department, 11600 W. 2nd Pl, Lakewood, CO 80228, USA; Medical Center of Plano, Trauma Research Department, 3901 W. 15th St, Plano, TX 75075, USA; Penrose Hospital, Trauma Research Department, 2222 N Nevada Ave, Colorado Springs, CO 80907, USA; Ampio Pharmaceuticals Inc, 373 Inverness Parkway Suite 200, Englewood, CO 80112, USA. Electronic address: gthomas@ampiopharma.com.
Gregory W
GW
Thomas
Swedish Medical Center, Trauma Research Department, 501 E. Hampden Ave, Englewood, CO 80113, USA; St. Anthony Hospital, Trauma Research Department, 11600 W. 2nd Pl, Lakewood, CO 80228, USA; Medical Center of Plano, Trauma Research Department, 3901 W. 15th St, Plano, TX 75075, USA; Penrose Hospital, Trauma Research Department, 2222 N Nevada Ave, Colorado Springs, CO 80907, USA; Ampio Pharmaceuticals Inc, 373 Inverness Parkway Suite 200, Englewood, CO 80112, USA. Electronic address: lrael@ampiopharma.com.
Leonard T
LT
Rael
Swedish Medical Center, Trauma Research Department, 501 E. Hampden Ave, Englewood, CO 80113, USA; St. Anthony Hospital, Trauma Research Department, 11600 W. 2nd Pl, Lakewood, CO 80228, USA; Medical Center of Plano, Trauma Research Department, 3901 W. 15th St, Plano, TX 75075, USA; Penrose Hospital, Trauma Research Department, 2222 N Nevada Ave, Colorado Springs, CO 80907, USA; Ampio Pharmaceuticals Inc, 373 Inverness Parkway Suite 200, Englewood, CO 80112, USA. Electronic address: mhausburg@ampiopharma.com.
Melissa
M
Hausburg
Swedish Medical Center, Trauma Research Department, 501 E. Hampden Ave, Englewood, CO 80113, USA; St. Anthony Hospital, Trauma Research Department, 11600 W. 2nd Pl, Lakewood, CO 80228, USA; Medical Center of Plano, Trauma Research Department, 3901 W. 15th St, Plano, TX 75075, USA; Penrose Hospital, Trauma Research Department, 2222 N Nevada Ave, Colorado Springs, CO 80907, USA; Ampio Pharmaceuticals Inc, 373 Inverness Parkway Suite 200, Englewood, CO 80112, USA. Electronic address: efredrick@ampiopharma.com.
Elizabeth D
ED
Frederick
Somalogic Inc, 2945 Wilderness Pl, Boulder, CO 80301, USA. Electronic address: ebrody@somalogic.com.
Edward
E
Brody
Swedish Medical Center, Trauma Research Department, 501 E. Hampden Ave, Englewood, CO 80113, USA; St. Anthony Hospital, Trauma Research Department, 11600 W. 2nd Pl, Lakewood, CO 80228, USA; Medical Center of Plano, Trauma Research Department, 3901 W. 15th St, Plano, TX 75075, USA; Penrose Hospital, Trauma Research Department, 2222 N Nevada Ave, Colorado Springs, CO 80907, USA; Ampio Pharmaceuticals Inc, 373 Inverness Parkway Suite 200, Englewood, CO 80112, USA. Electronic address: dbaror@ampiopharma.com.
David
D
Bar-Or
D000107:Acetylation / Q000187:drug effects; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D002199:Capillary Permeability / Q000187:drug effects; D002463:Cell Membrane Permeability / Q000187:drug effects; D002478:Cells, Cultured; D002867:Chromones / Q000494:pharmacology; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D008856:Microscopy, Fluorescence; D008970:Molecular Weight; D009025:Morpholines / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011725:Pyridines / Q000494:pharmacology; D012160:Retina / Q000166:cytology; D012709:Serum Albumin / Q000737:chemistry / Q000494:pharmacology*; D057900:Transcytosis / Q000187:drug effects*; D014404:Tubulin / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism
D002118:Calcium; D002867:Chromones; D007093:Imidazoles; D009025:Morpholines; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011725:Pyridines; D012709:Serum Albumin; D014404:Tubulin; D048051:p38 Mitogen-Activated Protein Kinases; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C093642:SB 203580
Acetylated α-tubulin; Calcium mobilization; Endothelial cells; Low molecular weight fraction of commercial 5% albumin; PI3-Kinase; p38 MAPK