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Am J Physiol Lung Cell Mol Physiol 294: L1233-L1237, 2008. First published April 18, 2008; doi:10.1152/ajplung.00076.2007
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Overexpression of the Na-K-ATPase {alpha}2-subunit improves lung liquid clearance during ventilation-induced lung injury

Yochai Adir,1,2 Lynn C. Welch,1 Vidas Dumasius,1 Phillip Factor,3 Jacob I. Sznajder,1 and Karen M. Ridge1,4

1Division of Pulmonary and Critical Care Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois; 2Division of Pulmonary Medicine, Carmel Medical Center, Rappaport Family Institute for Research in the Medical Sciences, Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel; 3Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York; and 4Jesse Brown Veterans Administration Medical Center-Lakeside Division, Chicago, Illinois

Submitted 27 February 2007 ; accepted in final form 9 April 2008


   ABSTRACT
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 ABSTRACT
METHODS
 RESULTS
 DISCUSSION
 GRANTS
 REFERENCES
 
Mechanical ventilation with high tidal volumes (HVT) impairs lung liquid clearance (LLC) and downregulates alveolar epithelial Na-K-ATPase. We have previously reported that the Na-K-ATPase {alpha}2-subunit contributes to LLC in normal rat lungs. Here we tested whether overexpression of Na-K-ATPase {alpha}2-subunit in the alveolar epithelium would increase clearance in a HVT model of lung injury. We infected rat lungs with a replication-incompetent adenovirus that expresses Na-K-ATPase {alpha}2-subunit gene (Ad{alpha}2) 7 days before HVT mechanical ventilation. HVT ventilation decreased LLC by ~50% in untreated, sham, and Adnull-infected rats. Overexpression of Na-K-ATPase {alpha}2-subunit prevented the decrease in clearance caused by HVT and was associated with significant increases in Na-K-ATPase {alpha}2 protein abundance and activity in peripheral lung basolateral membrane fractions. Ouabain at 10–5 M, a concentration that inhibits the {alpha}2 but not the Na-K-ATPase {alpha}1, decreased LLC in Ad{alpha}2-infected rats to the same level as sham and Adnull-infected lungs, suggesting that the increased clearance in Ad{alpha}2 lungs was due to Na-K-ATPase {alpha}2 expression and activity. In summary, we provide evidence that augmentation of the Na-K-ATPase {alpha}2-subunit, via gene transfer, may accelerate LLC in the injured lung.

acute respiratory distress syndrome; acute lung injury; experimental models; gene therapy

CLEARANCE OF PULMONARY EDEMA occurs via vectorial Na+ transport where water follows the Na+ gradients isosmotically. Na+ enters the alveolar epithelial cells mainly via apical amiloride-sensitive sodium channels and is extruded by the basolaterally located Na-K-ATPases (3, 8, 20, 21, 27, 30, 31). The Na-K-ATPase is a heteromeric enzyme composed of an {alpha}- and β-subunit. The {alpha}-subunit is the catalytic component of the enzyme containing the binding site for ATP as well as the receptor site for cardiac glycosides (22, 26). Four {alpha}-isoforms have been identified, each with a unique tissue distribution (28). The Na-K-ATPase {alpha}1- and {alpha}2-subunits have been reported in lung (25, 29). The smaller β-subunit is a glycosylated transmembrane molecule that controls {alpha}-/β-assembly and insertion of the Na-K-ATPase into the plasma membrane (29, 31).

In human lungs, the alveolar surface area available for fluid reabsorption and gas exchange is ~100 m2 and is composed of alveolar epithelial type I (ATI) and type II (ATII) cells (7). ATII cells cover 2–5%, whereas ATI cells cover ~95% of the surface area (7). Previous studies have shown that ATII cells are the main site for active sodium transport where ATI cells lack the Na-K-ATPase and serve as a barrier with no part in fluid clearance (13). However, recent reports demonstrated that ATI cells express the Na-K-ATPase {alpha}1-, {alpha}2-, and β1-isoforms and epithelial sodium channels (4, 15, 24), and, more importantly, ATI cells have a significant role in lung liquid clearance. Ridge et al. (24) reported that the Na-K-ATPase {alpha}2-subunit is responsible for ~60% of basal lung liquid clearance, and ~80% of the catecholamine-mediated increase in clearance occurs via upregulation of the Na-K-ATPase {alpha}2 in ATI cells.

Mechanical ventilation is used in the care of patients with acute respiratory failure; however, ventilation with high tidal volumes (HVT) may have deleterious effects and cause lung injury (1, 6, 32). It has been demonstrated that mechanical ventilation with HVT increases microvascular filtration coefficient in isolated lungs, produces pulmonary edema in intact animals, and also decreases alveolar epithelial Na-K-ATPase and active Na+ transport, thus impairing lung liquid clearance (1, 9, 32, 33).

Recently, we have demonstrated that adenoviral-mediated gene transfer results in overexpression of Na-K-ATPase subunits in the alveolar epithelium (12). Overexpression of the Na-K-ATPase {alpha}2-subunit was associated with a ~250% increase in lung liquid clearance (LLC) in normal rats (24), and a recent study suggests that Na-K-ATPase β1-subunit gene overexpression in the alveolar epithelium increases Na-K-ATPase function and LLC in a model of HVT (10). Therefore, we hypothesized that Na-K-ATPase {alpha}2-subunit (which is normally expressed in ATI cells) overexpression in the alveolar epithelium could positively affect LLC during HVT-induced lung injury in rats. To test this hypothesis, we infected rat lungs with a replication-incompetent adenovirus that expresses a rat Na-K-ATPase {alpha}2-subunit gene (Ad{alpha}2) compared with sham and Adnull-infected controls 7 days before HVT mechanical ventilation and measurement of LLC.


   METHODS
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 ABSTRACT
 METHODS
RESULTS
 DISCUSSION
 GRANTS
 REFERENCES
 
Adenovirus delivery. Replication-incompetent (E1a–/E3–) human type 5 adenoviruses containing expression cassettes with a human immediate/early CMV promoter/enhancer and a rat Na-K-ATPase {alpha}2-subunit cDNA (Ad{alpha}2) or no cDNA (AdNull) were constructed, propagated, purified, and titered as previously described (10). The use of animals for this study was approved by the Northwestern University Institutional Animal Care and Use Committee, according to the NIH guidelines. All animals were provided food and water ad libitum and were maintained on a 12:12-h light-dark cycle. Rats were anesthetized with 40 mg/kg pentobarbital intraperitoneally and orally intubated with a 14-g plastic catheter before adenoviral infection (24). Three experimental groups were studied: sham-surfactant, AdNull, and Ad{alpha}2. A mixture of adenovirus in a 50% surfactant/50% dialysis buffer vehicle was administered in four aliquots of 200 µl. Rats were rotated 90° between instillations given at 5-min intervals. Immediately before instillation, a forced exhalation was achieved by circumferential compression of the thorax. Compression was relinquished after endotracheal instillation of 200 µl of virus/vehicle followed by 800 µl of air. Rats were allowed to recover before extubation. Infected animals were maintained in separate isolator cages for 7 days before conducting experimental protocols.

HVT mechanical ventilation. Rats were anesthetized with pentobarbital (50 mg/kg ip), tracheotomized, and ventilated for 40 min with a HVT of 40 ml/kg (maximum peak airway pressures <35 cmH2O) and a respiratory rate of 50 breathes/min and compared with nonventilated controls.

Measurement of LLC. The isolated, fluid-filled, perfused lung preparation was performed immediately following HVT ventilation as previously described (1, 2, 10, 16). Changes in concentration of Evans blue-tagged albumin instilled into the air space were used to estimate the volume of fluid removed from the alveolar air space. The total unidirectional flux of Na+ from the alveolar space (i.e., active transport and passive movement) was calculated from the rate of loss of 22Na+ from the air spaces. Passive Na+ flux was calculated by subtracting the active Na+ flux (calculated from the rate of net fluid clearance) from total Na+ flux (27). Similarly, the flux of mannitol was calculated from the rate of loss of [3H]mannitol from the air spaces (27). Albumin flux from the pulmonary circulation into the alveolar space was determined from the fraction of FITC-labeled albumin, placed in the perfusate that appeared in the alveolar instillate during the experimental protocol.

Experimental protocols. Six experimental groups of rats were used in this study: nonventilated/noninfected (n = 6), Ad{alpha}2-infected nonventilated (n = 6), noninfected HVT (n = 6), Ad{alpha}2-infected + HVT (n = 6), Adnull + HVT (n = 4), and sham + HVT (n = 4). LLC was measured for two consecutive hours. In the first hour, LLC was measured in nonventilated/ventilated rats and infected/noninfected rats to assess the effect of the major intervention on edema clearance. In the second hour, ouabain (10–5 M) was administrated via the vascular perfusate to evaluate the role of Na-K-ATPase {alpha}2-subunit. LLC is expressed as percentage of the instillate volume.

Isolation and culture of alveolar epithelial cells. ATII cells were isolated from pathogen-free male Sprague-Dawley rats (200–225 g) as previously described. Briefly, the lungs were perfused via the pulmonary artery, lavaged, and digested with elastase (30 U/ml). ATII cells were purified by differential adherence to IgG-pretreated dishes, and cell viability was assessed by trypan blue exclusion (>95%). Cells were suspended in DMEM containing 10% FBS with 2 mM L-glutamine, 40 µg/ml gentamicin, 100 U/ml penicillin, and 100 µg/ml streptomycin and placed in culture for 7 days before the start of all experimental conditions. Cells were incubated in a humidified atmosphere of 5% CO2/95% air at 37°C.

Basolateral cell membrane isolation and Western blot analysis. Approximately two millimeters of peripheral lung tissue were collected from each lobe and homogenized to obtain whole cell lysates and basolateral membranes (BLM) as previously described (12, 17). Briefly, cell lysates were prepared by addition of lysis buffer (20 mM Tris, pH 7.5, 150 mM NaCl, 1 mM EDTA, 1 mM EGTA, 1% Triton X-100, 2.5 mM sodium pyrophosphate, 1 mM Na3VO4, 1 µg/ml leupeptin, 1 mM PMSF) and centrifugation at 14,000 g to eliminate the insoluble material. BLM were prepared using Percoll gradient centrifugation as previously described (12, 17). Peripheral lung tissue was homogenized in a buffer containing 300 mM mannitol in 12 mM Tris-HEPES, pH 7.6, and protease inhibitors as described above and centrifuged twice to discard the nuclear and mitochondrial pellet. Supernatant was centrifuged at 48,000 g for 30 min, and the BLM fraction was recovered after the membrane pellet was centrifuged in a 16% Percoll gradient at 48,000 g for 30 min. An equal amount of proteins from cell lysates or BLMs was resolved by 10% SDS-PAGE and analyzed by immunoblotting with specific monoclonal anti-rat Na-K-ATPase {alpha}2 (McB2, generous gift of K. Sweadner, Harvard University). The density of the bands was quantified and normalized to sham-infected controls.

Na-K-ATPase activity. Na-K-ATPase activity was determined by [32P]ATP hydrolysis as described before (18, 24). Briefly, ATII cells were placed on ice, and aliquots (~10 µg protein) were transferred to the Na-K-ATPase assay medium (final volume 100 µl) containing in mM: 50 NaCl, 5 KCl, 10 MgCl2, 1 EGTA, 50 Tris·HCl, 7 Na2ATP, and [{gamma}-32P]ATP (specific activity 3,000 Ci/mmol) in trace amounts (3.3 nCi/µl). The samples were then incubated at 37°C for 30 min, and the reaction was terminated by addition of 700 µl of TCA/charcoal (5%/10% wt/vol) suspension and rapid cooling to 4°C. After separating the charcoal phase (12,000 g for 5 min) containing the unhydrolyzed nucleotide, the liberated 32P was counted in an aliquot (200 µl) from the supernatant. Na-K-ATPase activity was calculated as the difference between test samples (total ATPase activity) and samples assayed in the same medium, but devoid of Na+ and K+ and in the presence of 4 mM ouabain (ouabain-insensitive ATPase activity) (18, 24). Results are expressed as mean nmol Pi/mg protein/hour of triplicate measurements from three animals per group.

Statistical analysis. Data are presented as mean values ± SD. One-way analysis of variance was used when multiple comparisons were made. Differences among groups were considered significant when P value was <0.05.


   RESULTS
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 RESULTS
DISCUSSION
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LLC. LLC was increased ~70% in rats infected with Ad{alpha}2 compared with control (n = 6), Adnull-infected (n = 4), or sham-infected rats (n = 4) (Fig. 1). In rats ventilated with HVT, LLC decreased by ~50% in noninfected control (n = 6), sham-infected (n = 4), and Adnull-infected (n = 4) rat lungs compared with nonventilated/noninfected control lungs (n = 6). Overexpression of the Na-K-ATPase {alpha}2-subunit restored the lung's ability to clear edema in rats exposed to HVT ventilation for 40 min (from 12% to 20.4% per hour) (Fig. 1).


Figure 1
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  		Fig. 1. Lung liquid clearance was increased in rat lungs with overexpressed Na-K-ATPase {alpha}2-subunit cDNA (Ad{alpha}2) compared with uninfected control (CT) rat lungs. Lung liquid clearance in Ad{alpha}2 lungs ventilated with high tidal volume (HVT) was 3-fold greater than in the other HVT groups and similar to nonventilated Ad{alpha}2 lungs. Data represent means ± SE. *P < 0.01. n.s., Not significant.

 
In rodent tissue, it is possible to distinguish physiologically between the Na-K-ATPase {alpha}1- and {alpha}2-subunits due to the large difference in their affinity for ouabain. The Na-K-ATPase {alpha}2-subunit, but not the Na-K-ATPase {alpha}1-subunit, is inhibited by 10 µM ouabain (24), whereas >1 mM ouabain is needed to inhibit the rat Na-K-ATPase {alpha}1-subunit (24). We determined the contribution of the Na-K-ATPase {alpha}2-subunit to LLC by perfusing 10 µM ouabain through the pulmonary circulation of the isolated rat lung model. In the presence of 10 µM ouabain, LLC was decreased ~60% in noninfected control, Adnull-, and sham-infected HVT rats compared with nonventilated/noninfected control rats, suggesting that the Na-K-ATPase {alpha}2 is important in LLC (Fig. 2). Importantly, in rat lungs infected with Ad{alpha}2 and subsequently ventilated with HVT, ~80% of the increase in LLC was due to the high-affinity ouabain-sensitive Na-K-ATPase {alpha}2-subunit (Fig. 2). Alveolar epithelial permeability to small solutes (22Na+ and [3H]mannitol) increased in rats ventilated with HVT for 40 min compared with noninfected, nonventilated control rats (Fig. 3). Evans blue dye-bound albumin instilled in the air space was not detected in the perfusate or bath compartments in any of the experimental groups. The movement of FITC-albumin from the pulmonary circulation into air space was increased in animals ventilated with HVT (Fig. 3).


Figure 2
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  		Fig. 2. Lung liquid clearance in isolated rat lungs was increased in HVT rat Na-K-ATPase {alpha}2-subunit cDNA (Ad{alpha}2) lungs compared with HVT lungs from uninfected control (CT), no cDNA (Adnull), and sham-infected rat lungs. Ouabain (5 x 10–5 M, black bars) inhibited the Ad{alpha}2-increased clearance. Data represent means ± SE. *P < 0.001 HVT Ad{alpha}2 (without ouabain, open bars) vs. all other ventilated groups.

 

Figure 3
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  		Fig. 3. Alveolar barrier permeability to solutes was assessed by measuring the flux of 22Na+ (black bars), [3H]mannitol (white bars) (A), and FITC-albumin (B) between the air space and vascular compartments of isolated rat lungs. Data represent means ± SE. CT, noninfected controls. In A, *P < 0.05 nonventilated controls vs. HVT control sham and Adnull. In B, *P < 0.05 vs. nonventilated, noninfected control subjects.

 
To determine whether the changes in LLC were due to changes in the expression and function of the Na-K-ATPase, we isolated BLM from peripheral lung tissue or ATII cells from HVT-ventilated and nonventilated rats infected with Ad{alpha}2, Adnull, or control, noninfected rats. As shown in Figs. 4 and 5, HVT resulted in a significant decrease in Na-K-ATPase {alpha}1, {alpha}2, and β1 protein abundance and Na-K-ATPase activity in Adnull and control, noninfected rats compared with nonventilated, Adnull-infected and control, noninfected rats. In contrast, there was an ~57% and 49% increase in Na-K-ATPase {alpha}2 protein abundance and Na-K-ATPase activity, respectively, in nonventilated, Ad{alpha}2-infected rats. Importantly, Na-K-ATPase {alpha}2 protein abundance and Na-K-ATPase activity was maintained in HVT-ventilated Ad{alpha}2 rats compared with HVT-ventilated Adnull-infected rats. These results suggest that overexpression of the Na-K-ATPase {alpha}2 protein maintains the Na-K-ATPase activity which then contributes to the restoration of LLC in rats exposed to HVT ventilation.


Figure 4
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  		Fig. 4. Representative Western blot for Na-K-ATPase {alpha}1- and {alpha}2-subunit protein (10 µg/lane) abundance in basolateral membranes isolated from peripheral lungs of rats ventilated with HVT for 40 min. Quantitative densitometric scan of blots are depicted in bar graphs. Data are means ± SD, n = 3. *P < 0.05. **P < 0.001 compared with nonventilated control.

 

Figure 5
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  		Fig. 5. Effect of mechanical ventilation on Na-K-ATPase activity. Na-K-ATPase activity decreased in primary alveolar epithelial type II cells isolated from rat lungs infected with either Adnull or Ad{alpha}2 and ventilated with HVT for 40 min. Bars represent means ± SD.

 

   DISCUSSION
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 METHODS
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Although mechanical ventilation is a life-saving procedure in patients with acute respiratory failure, it can also induce or worsen acute lung injury (1). Previous studies have shown that ventilation with HVT can disrupt the alveolo-capillary barrier, which results in leakage of fluid and blood constituents into the alveolar spaces as well release of inflammatory mediators (1, 5, 9, 23, 32, 33). Other reports have demonstrated that mechanical ventilation with HVT diminishes LLC. These changes were associated with decreased Na-K-ATPase activity in alveolar epithelial cells isolated from HVT-ventilated lungs (6, 9). Recently, several studies reported that both ATI and ATII cells have a role in active sodium transport and that ATI express both the Na-K-ATPase {alpha}1 and the {alpha}2 isozymes (4, 16, 24). It has also been suggested that the Na-K-ATPase {alpha}2 contributes to the active Na+ transport and LLC, which can be further increased by stimulation of the β-adrenergic receptor or by adenovirus-mediated overexpression of the Na-K-ATPase {alpha}2-subunit in noninjured, normal rat lungs (24).

In basal conditions, the Na-K-ATPase {alpha}1 is working at ~20–50% of its maximum capacity, whereas the Na-K-ATPase {alpha}2 is working at 1/20th of its Vmax (18). A previous report demonstrated that overexpression of the Na-K-ATPase {alpha}1 subunit in the rat epithelium did not increase Na-K-ATPase activity or LLC; however, overexpression of the Na-K-ATPase β1-subunit resulted in increased fluid clearance from rat lungs (12). Here, we report that overexpression of the Na-K-ATPase {alpha}2, which has been reported to be localized to rat ATI cells (24), plays an important role in LLC in the injured lung. We speculate that is due to the Na-K-ATPase {alpha}2-subunit's large reserve capacity to exchanging Na+ and K+ compared with the Na-K-ATPase {alpha}1-subunit. Since the ATI cells cover more than 95% of the alveolar surface area and express key transport proteins (i.e., Na+ channels and Na-K-ATPase), our results support the concept that ATI cells have an active role in LLC. HVT causes epithelial cell injury, including ATI cell damage, leading to edema in part due to the decreased ability of ATI cells to respond to the increased need of edema resolution. In patients with adult respiratory distress syndrome, impaired ability of the lung to clear edema was associated with worse outcomes (33), which prompted us to study whether overexpression of the Na-K-ATPase {alpha}2 would upregulate alveolar Na-K-ATPase function and sustain LLC in a HVT model of acute lung injury previously shown to impair alveolar active Na+ transport (16).

In the present study, we provide evidence that overexpressing the Na-K-ATPase {alpha}2 significantly increased LLC in a model of HVT ventilation in rats. HVT reduced LLC by ~50% in untreated, sham, and Adnull-infected controls confirming that this HVT model impairs alveolar fluid clearance in rats. Notably, overexpression of Na-K-ATPase {alpha}2-subunit was protective in rats ventilated with HVT as LLC was ~350% higher than in the other HVT groups. Clearance in the Ad{alpha}2/HVT lungs was 70% greater than nonventilated, uninfected controls and similar to Ad{alpha}2-overexpressing nonventilated lungs (see Fig. 1).

In rodent tissues the Na-K-ATPase {alpha}1- and {alpha}2-subunits can be distinguished by their low and high affinity for ouabain, respectively (22, 25, 26). As shown in Fig. 2, ouabain at 10–5 M, a concentration that predominantly inhibits the Na-K-ATPase {alpha}2, decreased LLC in Ad{alpha}2-infected lungs to the same level as sham and Adnull-infected lungs suggesting that the observed increases in LLC in Ad{alpha}2 lungs are due to increased Na-K-ATPase {alpha}2 activity. Western blot analysis of BLMs isolated from the peripheral lung of HVT rats demonstrated that {alpha}2-subunit gene transfer significantly increased the abundance of the {alpha}2-subunit protein, whereas HVT significantly decreased the {alpha}1-subunit protein in all rat lungs including HVT-Ad{alpha}2 rats. Also, we observed that {alpha}2-subunit overexpression was associated with a significant increase in Na-K-ATPase activity in BLM fractions isolated from the peripheral lung.

We have previously shown that adenoviral-mediated gene transfer can result in sustained overexpression of Na-K-ATPase in the lung for at least 10 days in rats, and overexpression of the Na-K-ATPase β1-subunit had beneficial effect in hyperoxic lung injury and restored LLC in the rat models of ventilator-induced lung injury and acute left atrial pressure elevation (1, 2, 10). During acute lung injury reduction of active Na+ transport, absorptive capacity and impairment of alveolar barrier function shifts transalveolar fluid balance toward air space edema accumulation which represents a significant challenge in the treatment of these patients. Adenoviral-mediated gene expression facilitates prolonged transgene expression and reduced host responses (14). High-efficient gene transfer to severely injured and edematous rats lungs has been previously demonstrated (11, 19), which is encouraging for the design of gene transfer strategies to treat patients with acute lung injury.

In summary, we provide the first evidence that overexpression of the {alpha}2 Na-K-ATPase subunit has a beneficial effect on the HVT ventilation-injured lung by upregulating LLC. Since the {alpha}2 Na-K-ATPase is expressed in ATI cells, which cover more than 95% of the alveolar surface area, our results support the notion that ATI cells may have a significant role in LLC, and augmentation of alveolar Na-K-ATPase function, via gene transfer, is of benefit during ventilation-induced lung injury.


   GRANTS
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 ABSTRACT
 METHODS
 RESULTS
 DISCUSSION
 GRANTS
REFERENCES
 
This work was funded in part by Veterans Affairs Merit (K. M. Ridge) and National Heart, Lung, and Blood Institute Grant HL-48129 (J. I. Sznajder).


   FOOTNOTES
 

Address for reprint requests and other correspondence: K. M. Ridge, Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern Univ., 240 E. Huron, McGaw M300, Chicago, IL 60611 (e-mail: kridge{at}northwestern.edu)

The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.


   REFERENCES
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 ABSTRACT
 METHODS
 RESULTS
 DISCUSSION
 GRANTS
 REFERENCES
 

  1. Adir Y, Factor P, Dumasius V, Ridge KM, Sznajder JI. Na,K-ATPase gene transfer increases liquid clearance during ventilation-induced lung injury. Am J Respir Crit Care Med 168: 1445–1448, 2003.[Abstract/Free Full Text]
  2. Azzam ZS, Dumasius V, Saldias FJ, Adir Y, Sznajder JI, Factor P. Na,K-ATPase overexpression improves alveolar fluid clearance in a rat model of elevated left atrial pressure. Circulation 105: 497–501, 2002.[Abstract/Free Full Text]
  3. Bertorello AM, Ridge KM, Chibalin AV, Katz AI, Sznajder JI. Isoproterenol increases Na+-K+-ATPase activity by membrane insertion of {alpha}-subunits in lung alveolar cells. Am J Physiol Lung Cell Mol Physiol 276: L20–L27, 1999.[Abstract/Free Full Text]
  4. Borok Z, Liebler JM, Lubman RL, Foster MJ, Zhou B, Li X, Zabski SM, Kim KJ, Crandall ED. Na transport proteins are expressed by rat alveolar epithelial type I cells. Am J Physiol Lung Cell Mol Physiol 282: L599–L608, 2002.[Abstract/Free Full Text]
  5. Carlton DP, Cummings JJ, Scheerer RG, Poulain FR, Bland RD. Lung overexpansion increases pulmonary microvascular protein permeability in young lambs. J Appl Physiol 69: 577–583, 1990.[Abstract/Free Full Text]
  6. Corbridge TC, Wood LD, Crawford GP, Chudoba MJ, Yanos J, Sznajder JI. Adverse effects of large tidal volume and low PEEP in canine acid aspiration. Am Rev Respir Dis 142: 311–315, 1990.[Web of Science][Medline]
  7. Crandall ED, Matthay MA. Alveolar epithelial transport. Basic science to clinical medicine. Am J Respir Crit Care Med 163: 1021–1029, 2001.[Free Full Text]
  8. Dada LA, Chandel NS, Ridge KM, Pedemonte C, Bertorello AM, Sznajder JI. Hypoxia-induced endocytosis of Na,K-ATPase in alveolar epithelial cells is mediated by mitochondrial reactive oxygen species and PKC-zeta. J Clin Invest 111: 1057–1064, 2003.[CrossRef][Web of Science][Medline]
  9. Dreyfuss D, Basset G, Soler P, Saumon G. Intermittent positive-pressure hyperventilation with high inflation pressures produces pulmonary microvascular injury in rats. Am Rev Respir Dis 132: 880–884, 1985.[Web of Science][Medline]
  10. Factor P, Dumasius V, Brown LA, Sznajder JI. Adenovirus-mediated transfer of an Na+/K+-ATPase beta1 subunit gene improves alveolar fluid clearance and survival in hyperoxic rats. Hum Gene Ther 11: 2231–2242, 2000.[CrossRef][Web of Science][Medline]
  11. Factor P, Mendez M, Mutlu GM, Dumasius V. Acute hyperoxic lung injury does not impede adenoviral-mediated alveolar gene transfer. Am J Respir Crit Care Med 165: 521–526, 2002.[Abstract/Free Full Text]
  12. Factor P, Saldias F, Ridge K, Dumasius V, Zabner J, Jaffe HA, Blanco G, Barnard M, Mercer R, Perrin R, Sznajder JI. Augmentation of lung liquid clearance via adenovirus-mediated transfer of a Na,K-ATPase beta1 subunit gene. J Clin Invest 102: 1421–1430, 1998.[Web of Science][Medline]
  13. Johnson M, Widdicombe J, Allen L, Barbry P, Dobbs L. Alveolar epithelial type I cells contain transport proteins and transport sodium, supporting an active role for type I cells in regulation of lung liquid homeostasis. Proc Natl Acad Sci USA 99: 1966–1971, 2002.[Abstract/Free Full Text]
  14. Kim IH, Jozkowicz A, Piedra PA, Oka K, Chan L. Lifetime correction of genetic deficiency in mice with a single injection of helper-dependent adenoviral vector. Proc Natl Acad Sci USA 98: 13282–13287, 2001.[Abstract/Free Full Text]
  15. Lecuona E, Saldias F, Comellas A, Ridge K, Guerrero C, Sznajder JI. Ventilator-associated lung injury decreases lung ability to clear edema and downregulates alveolar epithelial cell Na,K-adenosine triphosphatase function. Chest 116: 29S–30S, 1999.[CrossRef][Web of Science][Medline]
  16. Lecuona E, Saldias F, Comellas A, Ridge K, Guerrero C, Sznajder JI. Ventilator-associated lung injury decreases lung ability to clear edema in rats. Am J Respir Crit Care Med 159: 603–609, 1999.[Abstract/Free Full Text]
  17. Litvan J, Briva A, Wilson MS, Budinger GR, Sznajder JI, Ridge KM. Beta-adrenergic receptor stimulation and adenoviral overexpression of superoxide dismutase prevent the hypoxia-mediated decrease in Na,K-ATPase and alveolar fluid reabsorption. J Biol Chem 281: 19892–19898, 2006.[Abstract/Free Full Text]
  18. Lytton J, Lin JC, Guidotti G. Identification of two molecular forms of (Na+,K+)-ATPase in rat adipocytes. Relation to insulin stimulation of the enzyme. J Biol Chem 260: 1177–1184, 1985.[Abstract/Free Full Text]
  19. Machado-Aranda D, Adir Y, Young JL, Briva A, Budinger GR, Yeldandi AV, Sznajder JI, Dean DA. Gene transfer of the Na+,K+-ATPase beta1 subunit using electroporation increases lung liquid clearance. Am J Respir Crit Care Med 171: 204–211, 2005.[Abstract/Free Full Text]
  20. Matthay MA, Landolt CC, Staub NC. Differential liquid and protein clearance from the alveoli of anesthetized sheep. J Appl Physiol 53: 96–104, 1982.[Abstract/Free Full Text]
  21. Mutlu GM, Sznajder JI. Mechanisms of pulmonary edema clearance. Am J Physiol Lung Cell Mol Physiol 289: L685–L695, 2005.[Abstract/Free Full Text]
  22. Orlowski J, Lingrel JB. Differential expression of the Na,K-ATPase alpha1 and alpha2 genes in murine myogenic cell line. J Biol Chem 263: 17817–17821, 1988.[Abstract/Free Full Text]
  23. Ranieri VM, Giunta F, Suter PM, Slutsky AS. Mechanical ventilation as a mediator of multisystem organ failure in acute respiratory distress syndrome. JAMA 284: 43–44, 2000.[Free Full Text]
  24. Ridge K, Dada L, Lecuona E, Bertorello A, Katz A, Mochly-Rosen D, Sznajder J. Dopamine-induced exocytosis of the Na,K-ATPase is dependent on the activation of protein kinase C delta and epsilon. Mol Biol Cell 13: 1381–1389, 2002.[Abstract/Free Full Text]
  25. Ridge KM, Olivera WG, Saldias F, Azzam Z, Horowitz S, Rutschman DH, Dumasius V, Factor P, Sznajder JI. Alveolar type 1 cells express the alpha2 Na,K-ATPase, which contributes to lung liquid clearance. Circ Res 92: 453–460, 2003.[Abstract/Free Full Text]
  26. Ridge KM, Rutschman DH, Factor P, Katz AI, Bertorello AM, Sznajder JL. Differential expression of Na-K-ATPase isoforms in rat alveolar epithelial cells. Am J Physiol Lung Cell Mol Physiol 273: L246–L255, 1997.[Abstract/Free Full Text]
  27. Russo JJ, Manuli MA, Ismail-Beigi F, Sweadner KJ, Edelman IS. Na-K-ATPase in adipocyte differentiation in culture. Am J Physiol Cell Physiol 259: C968–C977, 1990.[Abstract/Free Full Text]
  28. Rutschman DH, Olivera W, Sznajder JI. Active transport and passive liquid movement in isolated perfused rat lungs. J Appl Physiol 75: 1574–1580, 1993.[Abstract/Free Full Text]
  29. Shull MM, Pugh DG, Lingrel JB. Characterization of the human Na,K-ATPase alpha 2 gene and identification of intragenic restriction fragment length polymorphisms. J Biol Chem 264: 17532–17543, 1989.[Abstract/Free Full Text]
  30. Shyjan AW, Levenson R. Antisera specific for the alpha 1, alpha 2, alpha 3, and beta subunits of the Na,K-ATPase: differential expression of alpha and beta subunits in rat tissue membranes. Biochemistry 28: 4531–4535, 1989.[CrossRef][Web of Science][Medline]
  31. Skou JC. The Na-K pump. NIPS 7: 95–100, 1992.[Abstract/Free Full Text]
  32. Sznajder JI, Factor P, Ingbar DH. Invited review: lung edema clearance: role of Na-K-ATPase. J Appl Physiol 93: 1860–1866, 2002.[Abstract/Free Full Text]
  33. Ware LB, Matthay M. Alveolar fluid clearance is impaired in the majority of patients with acute lung injury and the acute respiratory distress syndrome. Am J Respir Crit Care Med 163: 1376–1383, 2001.[Abstract/Free Full Text]



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E. N. Z. Yu, Z. P. Traylor, and I. C. Davis
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