Biomaterial Database

Gentamicin-induced alterations in phospholipid metabolism in cultured human proximal tubular cells. 1987

S Chatterjee

Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21205.

The effects of gentamicin on phospholipid levels and metabolism and the uptake of phosphatidylcholine (PC) adsorbed to low-density lipoprotein (LDL) were investigated in cultured human proximal tubular (PT) cells. Cells incubated with gentamicin (0.3 mM) for one to 21 days had a similar increase in the cell number and protein as compared to control cells. However, the cellular levels of phosphatidylcholine (PC) and sphingomyelin (SM), but not other phospholipids, increased in a time-dependent manner. Incubation of gentamicin (0.3 to 3.0 mM) resulted in a concentration-dependent increase in the cellular levels of PC (50% to 320%) and SM (20% to 40%). Gentamicin stimulated the incorporation of [14C]-acetate into diacylglycerol, PC, and SM in the order of 300%, 66%, and 20%, respectively, but not into lysophosphatidylcholine (LPC). Similarly, gentamicin stimulated the incorporation of [14C]-choline into PC and SM in the order of 300% and 172%, respectively, but not into LPC as compared to control cells. In addition, gentamicin also stimulated the incorporation of [14C]-choline into cytidine diphosphocholine (CDP-choline). However, the endocytosis of [14C]-PC-LDL was lower in cells incubated with gentamicin than in control cells. Thus, exogenously derived PC on LDL does not contribute to the increased cellular levels of PC in PT cells incubated with gentamicin. The activity of cytidine triphosphate (CTP):phosphocholine cytidyltransferase was moderately lower in cells incubated with gentamicin as compared to control. By contrast, the activity of phospholipase A1 and phospholipase C was twofold lower in cells incubated with gentamicin for 21 days as compared to control. Thus, increased incorporation of [14C]-acetate and [14C]-choline into PC in cells incubated with gentamicin may not only be due to increased endogenous synthesis but to decreased catabolism of newly synthesized PC. We conclude that gentamicin impairs the lysosomal catabolism of PC, leading to its accumulation in PT cells. This phenomenon may be an indication of gentamicin-induced nephrotoxicity in man.

UI	MeSH Term	Description	Entries
D007687	Kidney Tubules, Proximal	The renal tubule portion that extends from the BOWMAN CAPSULE in the KIDNEY CORTEX into the KIDNEY MEDULLA. The proximal tubule consists of a convoluted proximal segment in the cortex, and a distal straight segment descending into the medulla where it forms the U-shaped LOOP OF HENLE.	Proximal Kidney Tubule,Proximal Renal Tubule,Kidney Tubule, Proximal,Proximal Kidney Tubules,Proximal Renal Tubules,Renal Tubule, Proximal,Renal Tubules, Proximal,Tubule, Proximal Kidney,Tubule, Proximal Renal,Tubules, Proximal Kidney,Tubules, Proximal Renal
D008077	Lipoproteins, LDL	A class of lipoproteins of small size (18-25 nm) and light (1.019-1.063 g/ml) particles with a core composed mainly of CHOLESTEROL ESTERS and smaller amounts of TRIGLYCERIDES. The surface monolayer consists mostly of PHOSPHOLIPIDS, a single copy of APOLIPOPROTEIN B-100, and free cholesterol molecules. The main LDL function is to transport cholesterol and cholesterol esters to extrahepatic tissues.	Low-Density Lipoprotein,Low-Density Lipoproteins,beta-Lipoprotein,beta-Lipoproteins,LDL(1),LDL(2),LDL-1,LDL-2,LDL1,LDL2,Low-Density Lipoprotein 1,Low-Density Lipoprotein 2,LDL Lipoproteins,Lipoprotein, Low-Density,Lipoproteins, Low-Density,Low Density Lipoprotein,Low Density Lipoprotein 1,Low Density Lipoprotein 2,Low Density Lipoproteins,beta Lipoprotein,beta Lipoproteins
D009713	Nucleotidyltransferases	A class of enzymes that transfers nucleotidyl residues. EC 2.7.7.	Nucleotidyltransferase
D010740	Phospholipases	A class of enzymes that catalyze the hydrolysis of phosphoglycerides or glycerophosphatidates. EC 3.1.-.	Lecithinases,Lecithinase,Phospholipase
D010743	Phospholipids	Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.	Phosphatides,Phospholipid
D011506	Proteins	Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.	Gene Products, Protein,Gene Proteins,Protein,Protein Gene Products,Proteins, Gene
D002478	Cells, Cultured	Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.	Cultured Cells,Cell, Cultured,Cultured Cell
D005839	Gentamicins	A complex of closely related aminoglycosides obtained from MICROMONOSPORA purpurea and related species. They are broad-spectrum antibiotics, but may cause ear and kidney damage. They act to inhibit PROTEIN BIOSYNTHESIS.	Gentamicin Sulfate (USP),Gentamycin,G-Myticin,Garamycin,Gentacycol,Gentamicin,Gentamicin Sulfate,Gentamycins,Gentavet,Genticin,G Myticin,GMyticin,Sulfate, Gentamicin
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D019916	Choline-Phosphate Cytidylyltransferase	An enzyme that catalyzes the transfer of cytidylate (CMP) to choline phosphate to form CDPcholine. It is the rate-limiting enzyme in the choline pathway for the biosynthesis of phosphatidylcholine. Its activity is increased by glucocorticoids. EC 2.7.7.15.	CTP Phosphocholine Cytidylyltransferase,CDP-Choline Synthetase,CTP Phosphocholine Cytidylyl-Transferase,CTP Phosphorylcholine Cytidyltransferase,Phosphocholine Cytidyltransferase,Phosphorylcholine Cytidyl Transferase,CDP Choline Synthetase,CTP Phosphocholine Cytidylyl Transferase,Choline Phosphate Cytidylyltransferase,Cytidyl Transferase, Phosphorylcholine,Cytidyltransferase, CTP Phosphorylcholine,Cytidyltransferase, Phosphocholine,Cytidylyl-Transferase, CTP Phosphocholine,Cytidylyltransferase, CTP Phosphocholine,Cytidylyltransferase, Choline-Phosphate,Phosphocholine Cytidylyl-Transferase, CTP,Phosphocholine Cytidylyltransferase, CTP,Phosphorylcholine Cytidyltransferase, CTP,Synthetase, CDP-Choline,Transferase, Phosphorylcholine Cytidyl