Induction of intracellular glutathione in alveolar type II pneumocytes following BCNU exposure

1994 ◽  
Vol 266 (2) ◽  
pp. L125-L130 ◽  
Author(s):  
S. G. Jenkinson ◽  
R. A. Lawrence ◽  
C. A. Zamora ◽  
S. M. Deneke
Keyword(s):  
Intracellular Transport ◽  
Oxidant Stress ◽  
Alveolar Type ◽  
Synthetase Activity ◽  
Type Ii ◽  
Gamma Glutamyl Transpeptidase ◽  
Type Ii Pneumocytes ◽  
Oxidant Damage ◽  
Glutamylcysteine Synthetase ◽  
Glutamyl Transpeptidase

N,N'-bis(2-chloroethyl)-N-nitro-sourea (BCNU) is a potent inhibitor of glutathione reductase (GSSG-Red) activity in both tissues and cells. We examined the effects of treating alveolar type II cells with BCNU and found that a marked decrease in cellular GSSG-Red activity occurred in these cells associated with a time-dependent increase in cellular glutathione (GSH) concentrations. The increase in GSH was not found to be related to changes in cellular gamma-glutamyl transpeptidase activity, gamma-glutamylcysteine synthetase activity, nor increased intracellular transport of cystine. When the BCNU-exposed cells were incubated with hydrogen peroxide to produce oxidant stress, the cells exhibited increased susceptibility to oxidant damage when compared with controls, despite the fact that cellular concentrations of GSH were markedly elevated.

scholarly journals Glutathione replenishment capacity is lower in isolated perivenous than in periportal hepatocytes

1988 ◽  
Vol 254 (2) ◽  
pp. 411-417 ◽  
Author(s):  
Y Kera ◽  
K E Penttilä ◽  
K O Lindros
Keyword(s):  
Glutathione Synthetase ◽  
Synthetase Activity ◽  
Gamma Glutamyl Transpeptidase ◽  
Zonal Distribution ◽  
Significant Difference ◽  
Glutamylcysteine Synthetase ◽  
Gsh Metabolism ◽  
Collagenase Perfusion ◽  
Sulphur Amino Acids ◽  
Glutamyl Transpeptidase

The zonal distribution of GSH metabolism was investigated by comparing hepatocytes obtained from the periportal (zone 1) or perivenous (zone 3) region by digitonin/collagenase perfusion. Freshly isolated periportal and perivenous cells had similar viability (dye exclusion, lactate dehydrogenase leakage and ATP content) and GSH content (2.4 and 2.7 mumol/g respectively). During incubation, periportal cells slowly accumulated GSH (0.35 mumol/h per g), whereas in perivenous cells a decrease occurred (-0.14 mumol/h per g). Also, in the presence of either L-methionine or L-cysteine (0.5 mM) periportal hepatocytes accumulated GSH much faster (3.5 mumol/h per g) than did perivenous cells (1.9 mumol/h per g). These periportal-perivenous differences were also found in cells from fasted rats. Efflux of GSH was faster from perivenous cells than from periportal cells, but this difference only explained 10-20% of the periportal-perivenous difference in accumulation. Furthermore, periportal cells accumulated GSH to a plateau 26-40% higher than in perivenous cells. There was no significant difference in gamma-glutamylcysteine synthetase or glutathione synthetase activity between the periportal and perivenous cell preparations. The periportal-perivenous difference in GSH accumulation was unaffected by inhibition of gamma-glutamyl transpeptidase or by 5 mM-glutamate or -glutamine, but was slightly diminished by 2 mM-L-methionine. This suggests differences between periportal and perivenous cells in their metabolism and/or transport of (sulphur) amino acids. Our results suggest that a lower GSH replenishment capacity of the hepatocytes from the perivenous region may contribute to the greater vulnerability of this region to xenobiotic damage.

Peroxynitrite Inhibition of Oxygen Consumption and Ion Transport in Alveolar Type II Pneumocytes

CHEST Journal ◽  
1994 ◽  
Vol 105 (3) ◽  
pp. 74S ◽  
Author(s):  
Sadis Matalon ◽  
Ping Hu ◽  
H. Ischiropoulos ◽  
Joseph S. Beckman
Keyword(s):  
Oxygen Consumption ◽  
Ion Transport ◽  
Alveolar Type ◽  
Type Ii ◽  
Type Ii Pneumocytes

scholarly journals ICAM-1 and integrin expression on isolated human alveolar type II pneumocytes

1994 ◽  
Vol 7 (4) ◽  
pp. 736-739 ◽  
Author(s):  
J. Guzman ◽  
T. Izumi ◽  
S. Nagai ◽  
U. Costabel
Keyword(s):  
Alveolar Type ◽  
Integrin Expression ◽  
Type Ii ◽  
Type Ii Pneumocytes

scholarly journals Effect of Hyaluronic Acid on the Differentiation of Mesenchymal Stem Cells into Mature Type II Pneumocytes

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2928
Author(s):  
Francesca Della Sala ◽  
Mario di Gennaro ◽  
Gianluca Lista ◽  
Francesco Messina ◽  
Luigi Ambrosio ◽  
...  
Keyword(s):  
Hyaluronic Acid ◽  
Lung Surfactant ◽  
Repair Process ◽  
Surfactant Protein ◽  
Alveolar Type ◽  
Type Ii ◽  
Type Ii Pneumocytes ◽  
Mature Type ◽  
Pulmonary Damage ◽  
Msc Differentiation

Hyaluronic acid (HA) is an essential component of the extracellular matrix (ECM) of the healthy lung, playing an important role in the structure of the alveolar surface stabilizing the surfactant proteins. Alveolar type II (ATII) cells are the fundamental element of the alveolus, specializing in surfactant production. ATII cells represent the main target of lung external lesion and a cornerstone in the repair process of pulmonary damage. In this context, knowledge of the factors influencing mesenchymal stem cell (MSC) differentiation in ATII cells is pivotal in fulfilling therapeutic strategies based on MSCs in lung regenerative medicine. To achieve this goal, the role of HA in promoting the differentiation of MSCs in mature Type II pneumocytes capable of secreting pulmonary surfactant was evaluated. Results demonstrated that HA, at a specific molecular weight can greatly increase the expression of lung surfactant protein, indicating the ability of HA to influence MSC differentiation in ATII cells.

Endocytosed SP-A and surfactant lipids are sorted to different organelles in rat type II pneumocytes

2001 ◽  
Vol 281 (2) ◽  
pp. L345-L360 ◽  
Author(s):  
Heide Wissel ◽  
Andrea Lehfeldt ◽  
Petra Klein ◽  
Torsten Müller ◽  
Paul A. Stevens
Keyword(s):  
Cell Surface ◽  
Intracellular Transport ◽  
Protein A ◽  
Lamellar Body ◽  
Surfactant Protein ◽  
Type Ii Cells ◽  
Type Ii ◽  
Lamellar Bodies ◽  
Type Ii Pneumocytes ◽  
Early Endosomes

Intracellular transport of endocytosed surfactant protein A (SP-A) and lipid was investigated in isolated rat type II cells. After internalization, SP-A and lipid are taken up via the coated-pit pathway and reside in a common compartment, positive for the early endosomal marker EEA1 but negative for the lamellar body marker 3C9. SP-A then recycles rapidly to the cell surface via Rab4-associated recycling vesicles. Internalized lipid is transported toward a Rab7-, CD63-, 3C9-positive compartment, i.e., lamellar bodies. Inhibition of calmodulin led to inhibition of uptake and transport out of the EEA1-positive endosome and thus of resecretion of both components. Inhibition of intravesicular acidification (bafilomycin A1) led to decreased uptake of both surfactant components. It inhibited transport out of early endosomes for lipid only, not for SP-A. We conclude that in type II cells, endocytosed SP-A and lipid are transported toward a common early endosomal compartment. Thereafter, both components dissociate. SP-A is rapidly recycled to the cell surface and does not enter classic lamellar bodies. Lipid is transported toward lamellar bodies.

Amiloride-inhibitable Na+ conductive pathways in alveolar type II pneumocytes

1991 ◽  
Vol 260 (2) ◽  
pp. L90-L96 ◽  
Author(s):  
S. Matalon ◽  
R. J. Bridges ◽  
D. J. Benos
Keyword(s):  
Membrane Vesicle ◽  
Membrane Vesicles ◽  
Na Channel ◽  
Plasma Membrane Vesicle ◽  
Alveolar Type ◽  
Type Ii ◽  
Type Ii Pneumocytes ◽  
The Difference ◽  
22Na Uptake ◽  
Na Uptake

The purpose of these studies was to document the existence of electrogenic Na+ uptake by membrane vesicles of rabbit alveolar type II (ATII) cells and the extent to which this process was inhibited by amiloride. ATII cells (greater than 85% pure) were obtained by elastase digestion of lung tissue followed by Percoll centrifugation, and an enriched plasma membrane vesicle fraction was obtained by differential centrifugation. 22Na+ uptake into these vesicles was measured in the presence of a negative inside membrane potential, produced by the addition of the K+ ionophore valinomycin (10 microM) after all external K+ was removed. Electrogenic (valinomycin-sensitive) Na+ uptake (ELNa) was defined as the difference in uptake in the presence and absence of valinomycin. ELNa, normalized per milligram protein, was twice as high across ATII cells than alveolar macrophage membrane vesicles, was inhibited by amiloride (50% inhibitory concentration = 10 microM), and was decreased in the presence of an outwardly directed proton gradient (pHin 6.8; pHout 7.8), suggesting that it was not mediated by Na(+)-H+ antiport. Furthermore, ELNa was equally inhibited by increasing concentrations of amiloride and benzamil but was more sensitive to 5-(N-ethyl-N-isopropyl)-2'-4'-amiloride in concentrations of 10–1,000 microM. These findings indicate that a fraction of Na+ transport across ATII membrane vesicles occurs through a conductive pathway, probably a channel, that has different sensitivity to amiloride and its analogues than the previously described epithelial high amiloride-affinity Na+ channel.

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