#1504 Pediatr Res 2006

Pediatric research, 2011

The effects of estradiol (E2) and progesterone (P) on alveolar epithelial Na+ transport were studied in isolated alveolar epithelial cells from 18- to 19-d GA rat fetuses, grown to confluence in serum-free media supplemented with E2 (0-1 μM) and P (0-2.8 μM). Short-circuit currents (ISC) were measured, showing an increase by E2 and P in a dose-dependent manner. The Na,K-ATPase subunits -α1 and -β1 were detected by Western blotting, but total expression was not significantly altered. Furthermore, all three epithelial Na+ channel (ENaC) subunits -α, -β, and -γ were detected, with trends toward a higher expression in the presence of E2 and P. Real-time PCR revealed an increase of α- and β-ENaC expression but no alteration of γ-ENaC. In addition, the mRNA expression of cystic fibrosis transmembrane conductance regulator (CFTR) and Na,K-ATPase-β1 subunit were elevated in the presence of E2 and P. Single-channel patch clamp analysis demonstrated putative highly selective and nonselective ...

Pediatric Research, 2006

Abbreviations: AFC, alveolar fluid clearance; BPD, bronchopulmonary dysplasia; E2, 17-␤-estradiol (pg/mL ϫ 3.671 ϭ pmol/L); ENaC, epithelial sodium channel; ICI 182.780, 7␣-[9-[(4,4,5,5,5-pentafluoropentyl)sulfinyl] nonyl]-estra-1,3,5(10)-triene-3,1 7␤-diol; P, progesterone (ng/mL ϫ 3.18 ϭ nmol/L); RTI 3021-022,

American Journal of Physiology-Lung Cellular and Molecular Physiology, 2017

Alveolar fluid clearance mediates perinatal lung transition to air breathing in newborn infants, which is accomplished by epithelial Na+ channels (ENaC) and Na-K-ATPase. Male sex represents a major risk factor for developing respiratory distress, especially in preterm infants. We previously showed that male sex is associated with reduced epithelial Na+ transport, possibly contributing to the sexual dimorphism in newborn respiratory distress. This study aimed to determine sex-specific effects of sex steroids on epithelial Na+ transport. The effects of testosterone, 5α-dihydrotestosterone (DHT), estradiol, and progesterone on Na+ transport and Na+ channel expression were determined in fetal distal lung epithelial (FDLE) cells of male and female rat fetuses by Ussing chamber and mRNA expression analyses. DHT showed a minor effect only in male FDLE cells by decreasing epithelial Na+ transport. However, flutamide, an androgen receptor antagonist, did not abolish the gender imbalance, and...

PLOS ONE, 2015

Respiratory distress syndrome (RDS) is the most frequent pulmonary complication in preterm infants. RDS incidence differs between genders, which has been called the male disadvantage. Besides maturation of the surfactant system, Na + transport driven alveolar fluid clearance is crucial for the prevention of RDS. Na + transport is mediated by the epithelial Na + channel (ENaC) and the Na,K-ATPase, therefore potential differences in their expression or activity possibly contribute to the gender imbalance observed in RDS. Fetal distal lung epithelial (FDLE) cells of rat fetuses were separated by sex and analyzed regarding expression and activity of the Na + transporters. Ussing chamber experiments showed a higher baseline short-circuit current (I SC ) and amiloride-sensitive ΔI SC in FDLE cells of female origin. In addition, maximal amiloride-sensitive ΔI SC and maximal ouabain-sensitive ΔI SC of female cells were higher when measured in the presence of a permeabilized basolateral or apical membrane, respectively. The number of FDLE cells per fetus recoverable during cell isolation was also significantly higher in females. In addition, lung wet-to-dry weight ratio was lower in fetal and newborn female pups. Female derived FDLE cells had higher mRNA levels of the ENaC-and Na,K-ATPase subunits. Furthermore, estrogen (ER) and progesterone receptor (PR) mRNA levels were higher in female cells, which might render female cells more responsive, while concentrations of placenta-derived sex steroids do not differ between both genders during fetal life. Inhibition of ER-β abolished the sex differences in Na + transport and female cells were more responsive to estradiol stimulation. In conclusion, a higher alveolar Na + transport, possibly attributable to a higher expression of hormone receptors in female FDLE cells, provides an explanation for the well known sexrelated difference in RDS occurrence and outcome.

American Journal of Physiology-lung Cellular and Molecular Physiology, 2017

Alveolar fluid clearance mediates perinatal lung transition to air breathing in newborn infants, which is accomplished by epithelial Na ϩ channels (ENaC) and Na-K-ATPase. Male sex represents a major risk factor for developing respiratory distress, especially in preterm infants. We previously showed that male sex is associated with reduced epithelial Na ϩ transport, possibly contributing to the sexual dimorphism in newborn respiratory distress. This study aimed to determine sex-specific effects of sex steroids on epithelial Na ϩ transport. The effects of testosterone, 5␣-dihydrotestosterone (DHT), estradiol, and progesterone on Na ϩ transport and Na ϩ channel expression were determined in fetal distal lung epithelial (FDLE) cells of male and female rat fetuses by Ussing chamber and mRNA expression analyses. DHT showed a minor effect only in male FDLE cells by decreasing epithelial Na ϩ transport. However, flutamide, an androgen receptor antagonist, did not abolish the gender imbalance, and testosterone lacked any effect on Na ϩ transport in male and female FDLE cells. In contrast, estradiol and progesterone increased Na ϩ transport and Na ϩ channel expression especially in females, and prevented the inhibiting effect of DHT in males. Estrogen receptor inhibition decreased Na ϩ channel expression and eliminated the sex differences. In conclusion, female sex steroids stimulate Na ϩ transport especially in females and prevent the inhibitory effect of DHT in males. The ineffectiveness of testosterone suggests that Na ϩ transport is largely unaffected by androgens. Thus, the higher responsiveness of female cells to female sex steroids explains the higher Na ϩ transport activity, possibly leading to a functional advantage in females.

PloS one, 2014

Airway epithelial mucus hypersecretion and mucus plugging are prominent pathologic features of chronic inflammatory conditions of the airway (e.g. asthma and cystic fibrosis) and in most of these conditions, women have worse prognosis compared with male patients. We thus investigated the effects of estradiol on mucus expression in primary normal human bronchial epithelial cells from female donors grown at an air liquid interface (ALI). Treatment with estradiol in physiological ranges for 2 weeks caused a concentration-dependent increase in the number of PAS-positive cells (confirmed to be goblet cells by MUC5AC immunostaining) in ALI cultures, and this action was attenuated by estrogen receptor beta (ER-β) antagonist. Protein microarray data showed that nuclear factor of activated T-cell (NFAT) in the nuclear fraction of NHBE cells was increased with estradiol treatment. Estradiol increased NFATc1 mRNA and protein in ALI cultures. In a human airway epithelial (1HAE0) cell line, NFAT...

Journal of Endocrinology, 2014

Changes in the androgen levels in asthmatic men may be associated with the severity of asthma. 23 Androgens induce a nongenomic relaxation in airway smooth muscle but their underlying 24 mechanisms remain unclear. The aim of this study was to investigate the potential 25 bronchorelaxing action of testosterone (TES) and its metabolites (5α-and 5β-DHT). A 26 preventive effect of the OVA-induced bronchospasm was observed in sensitized guinea pigs for 27 each androgen. Androgens were studied in response to bronchoconstrictors: carbachol (CCh) and 28 KCl in isolated trachea rings with and without epithelium from non-sensitized and sensitized 29 animals as well as on ovalbumin (OVA)-induced contraction. Androgens concentration-30 dependently abolished the contraction to CCh, KCl and OVA. There were significant differences 31 in the sensitivity to the relaxation induced by each androgen. 5β-DHT was more potent to relax 32 KCl-induced contraction while TES and 5α-DHT were more potent on CCh-and OVA-induced 33 contraction. No differences were found in preparations with and without epithelium or in the 34 presence of a nitric oxide synthase inhibitor or an inhibitor of the K + channels. These data 35 discard the epithelium-, nitric oxide-and K + channels-dependent pathway in androgen-induced 36 relaxation. However, in fura 2-loaded, dissociated tracheal myocytes, physiological 37 concentrations of androgens decreased the KCl-induced [Ca 2+ ] i increment. 5β-DHT was the most 38 potent to decrease KCl-induced [Ca 2+ ] i increment and prevent bronchospasm. We suggest that 39 androgen-induced brochorelaxation was mediated via decreased Ca 2+ influx through L-type

AJP: Lung Cellular and Molecular Physiology, 2011

Cell membrane phospholipids, like phosphatidylinositol 4,5-bisphosphate [PI( 4 , 5 )P2], can regulate epithelial Na channel (ENaC) activity. Gender differences in lung ENaC expression have also been demonstrated. However, the effects in vivo on alveolar fluid clearance are uncertain. Thus PI( 4 , 5 )P2 effects on alveolar fluid clearance were studied in male and female rats. An isosmolar 5% albumin solution was intrapulmonary instilled; alveolar fluid clearance was studied for 1 h. Female rats had a 37 ± 19% higher baseline alveolar fluid clearance than male rats. Bilateral ovariectomy attenuated this gender difference. Compared with controls, PI( 4 , 5 )P2 instillation (300 μM) increased alveolar fluid clearance by ∼93% in both genders. Amiloride or the specific αENaC small-interfering RNA inhibited baseline and PI( 4 , 5 )P2-stimulated alveolar fluid clearance in both genders, indicating a dependence on amiloride-sensitive pathways. The fraction of amiloride inhibition was greater...

Cummings, James J. Nitric oxide decreases lung liquid production in fetal lambs. J. Appl. Physiol. 83(5): 1538-1544, 1997.-To examine the effect of nitric oxide on fetal lung liquid production, I measured lung liquid production in fetal sheep at 130 Ϯ 5 days gestation (range 122-137 days) before and after intrapulmonary instillation of nitric oxide. Thirtyone studies were done in which net lung luminal liquid production (Jv) was measured by plotting the change in lung luminal liquid concentration of radiolabeled albumin, an impermeant tracer that was mixed into the lung liquid at the start of each study. To see whether changes in Jv might be associated with changes in pulmonary hemodynamics, pulmonary and systemic pressures were measured and left pulmonary arterial flow was measured by an ultrasonic Doppler flow probe. Variables were measured during a 1-to 2-h control period and for 4 h after a small bolus of isotonic saline saturated with nitric oxide gas (10 or 100%) was instilled into the lung liquid. Control (saline) instillations (n ϭ 6) caused no change in any variable over 6 h. Nitric oxide instillation significantly decreased Jv and increased pulmonary blood flow; these effects were sustained for 1-2 h. There was also a significant but transient decrease in pulmonary arterial pressure. Thus intrapulmonary nitric oxide causes a significant decrease in lung liquid and is associated with a decrease in pulmonary vascular resistance. In a separate series of experiments either amiloride or benzamil, which blocks Na ϩ transport, was mixed into the lung liquid before nitric oxide instillation; still, there was a similar reduction in lung liquid production. Thus the reduction in lung liquid secretion caused by nitric oxide does not appear to depend on apical Na ϩ efflux. pulmonary circulation; ion transport; birth transition; fetus

Respiratory Physiology & Neurobiology, 2003

The aim of this animal study was to test the hypothesis that low and high doses of 17b-estradiol (E 2 ) may differentially influence airway responsiveness. Ovariectomized female rats received either placebo or E 2 (10 or 100 mg/kg per day) for 21 days. The concentration of inhaled acetylcholine (ACh) required to double pulmonary resistance (EC 200 RL) was calculated as the in vivo index of airway responsiveness. Ex vivo airway responsiveness was evaluated by the cumulative concentration-response curve (CCRC) of isolated tracheal segments. Rats treated with low-dose E 2 were less responsive to ACh than rats given either placebo or high-dose E 2 (P 0/0.003). Ex vivo, low-dose E 2 treatment decreased (P0/0.01) and high-dose E 2 increased the potency of ACh (P B/0.001) compared to placebo. E 2 treatment did not alter smooth muscle cross-sectional area or epithelium thickness. Accumulation of liquid within the tracheal mucosa was moderately enhanced by high-dose E 2 treatment compared with animals given either placebo or low-dose E 2 (P0/0.03). We conclude that E 2 treatment has differential, dose-dependent effects on airway responsiveness to acetylcholine. #