Dexamethasone reduces Cftr channel activity in FDLE cells.

<p>Graphs represent the mean + SEM of I_SC in response to 100 nM dexamethasone for 24, 48 and 72 h measured in Ussing chambers. <b>A:</b> Forskolin-induced I_SC (n = 25–56, *** p<0.001, ANOVA with Tukey's <i>post hoc</i> test). <b>B:</b> Glibenclamide-sensitive I_SC (n = 25–55, *** p<0.001, ANOVA with Tukey's <i>post hoc</i> test). <b>C:</b> Typical current tracing of FDLE monolayers.</p

LY-294002 prevents the increase of CFTR activity induced by dexamethasone in Calu-3 cells.

<p>Graphs represent the mean + SEM of I_SC in response to 100 nM dexamethasone and LY-294002 for 24 h measured in Ussing chambers. <b>A:</b> Forskolin-induced I_SC (n = 12–18, ** p<0.01, *** p<0.001, ANOVA with Tukey's <i>post hoc</i> test). <b>B:</b> CFTR_inh172-sensitive I_SC (n = 12–18, * p<0.05, ** p<0.01, *** p<0.001, ANOVA with Tukey's <i>post hoc</i> test).</p

Dexamethasone reduces CFTR/Cftr mRNA expression and channel activity in adult alveolar cells.

<p><b>A/B:</b> primary adult ATII cells. <b>A:</b> Graph represents the mean + SEM for normalized Cftr mRNA expression in response to 100 nM dexamethasone for 24 h acquired by RT-qPCR (n = 6, *** p<0.001 by T-test compared to control monolayers without dexamethasone addition). <b>B:</b> Graph represents the mean + SEM of I_SC in response to 100 nM dexamethasone for 24 h measured in Ussing chambers. Forskolin-induced I_SC (n = 29–31, * p<0.05 by T-test compared to control monolayers without dexamethasone addition) and glibenclamide-sensitive I_SC (n = 27–28). <b>C:</b> A549 cells. Graph represents the mean + SEM for normalized CFTR mRNA expression in response to 100 nM dexamethasone for 24 h acquired by RT-qPCR (n = 8, *** p<0.001, T-test compared to control cells without dexamethasone addition).</p

Gene-specific primers.

<p>Gene-specific primers.</p

Dexamethasone reduces CFTR/Cftr mRNA expression and increases channel activity in airway epithelial cells.

<p><b>A/B:</b> Graphs represent the mean + SEM for normalized CFTR/Cftr mRNA expression in response to 100 nM dexamethasone for 24 h acquired by RT-qPCR. <b>A:</b> 16HBE14o- cells (n = 8, *** p<0.001, T-test compared to control cells without dexamethasone addition). <b>B:</b> Primary rat airway epithelial cells (n = 7–8, *** p<0.001, T-test compared to control cells without dexamethasone addition). <b>C:</b> Typical current tracing of primary airway epithelial cells. D/E: Graphs represent the mean + SEM of I_SC in response to 100 nM dexamethasone for 24 h measured in Ussing chambers. <b>D:</b> Forskolin-induced I_SC (n = 20–23, ** p<0.01, T-test compared to control cells without dexamethasone addition). E: CFTR₁₇₂inh-sensitive I_SC (n = 19–20, ** p<0.01, T-test compared to control cells without dexamethasone addition).</p

Dexamethasone reduces Cftr mRNA expression in FDLE cells.

<p>Graphs represent the mean + SEM for normalized Cftr mRNA expression acquired by RT-qPCR. <b>A:</b> Dose-response curve of dexamethasone effect (1 nM–1 μM for 24 h, n = 4, ** p<0.01; *** p<0.001, ANOVA with Dunnett's <i>post hoc</i> test compared to control monolayers without dexamethasone addition). <b>B:</b> Time course of Cftr mRNA expression in response to 100 nM dexamethasone for 6, 12 and 24 h (n = 4, * p<0.05; ** p<0.01; *** p<0.001, T-test).</p

Mifepristone restores CFTR mRNA expression and reduces channel activity in the presence of dexamethasone in Calu-3 cells.

<p><b>A:</b> Graph represents the mean + SEM for normalized CFTR mRNA expression in response to 100 nM dexamethasone and mifepristone for 24 h acquired by RT-qPCR (n = 3–4, * p<0.05, ** p<0.01, *** p<0.001, ANOVA with Tukey's <i>post hoc</i> test). <b>B/C:</b> Graphs represent the mean + SEM of I_SC in response to 100 nM dexamethasone and mifepristone for 24 h measured in Ussing chambers. <b>B:</b> Forskolin-induced I_SC (n = 7–12, * p<0.05, ** p<0.01, ANOVA with Tukey's <i>post hoc</i> test). <b>C:</b> CFTR_inh172-sensitive I_SC (n = 7–12, * p<0.05, ANOVA with Tukey's <i>post hoc</i> test).</p

Dexamethasone reduces CFTR mRNA expression and increases channel activity in Calu-3 cells.

<p><b>A:</b> Graph represents the mean + SEM for normalized CFTR mRNA expression in response to 100 nM dexamethasone for 24 h acquired by RT-qPCR (n = 6, *** p<0.001, T-test compared to control cells without dexamethasone addition). <b>B/C/E/F:</b> Graphs represent the mean + SEM of I_SC in response to 100 nM dexamethasone for 24 h measured in Ussing chambers. <b>B:</b> Forskolin-induced I_SC (n = 12, *** p<0.001, T-test compared to control cells without dexamethasone addition). <b>C:</b> Glibenclamide-sensitive I_SC (n = 6, ** p<0.01, T-test compared to control cells without dexamethasone addition). <b>D:</b> Typical current tracing of Calu-3 cells. <b>E:</b> Forskolin-induced I_SC measured in Cl^--free solution (n = 14–16, ns = not significant). <b>F:</b> Forskolin-induced I_SC measured in HCO₃^--free solution (n = 16, * p<0.05, T-test compared to control cells without dexamethasone addition).</p

Primer sequences.

<p>Primer sequences.</p

Therapeutic potential of mesenchymal stem cells for pulmonary complications associated with preterm birth

Preterm infants frequently suffer from pulmonary complications resulting in significant morbidity and mortality. Physiological and structural lung immaturity impairs perinatal lung transition to air breathing resulting in respiratory distress. Mechanical ventilation and oxygen supplementation ensure sufficient oxygen supply but enhance inflammatory processes which might lead to the establishment of a chronic lung disease called bronchopulmonary dysplasia (BPD). Current therapeutic options to prevent or treat BPD are limited and have salient side effects, highlighting the need for new therapeutic approaches. Mesenchymal stem cells (MSCs) have demonstrated therapeutic potential in animal models of BPD. This review focuses on MSC-based therapeutic approaches to treat pulmonary complications and critically compares results obtained in BPD models. Thereby bottlenecks in the translational systems are identified that are preventing progress in combating BPD. Notably, current animal models closely resemble the so-called "old" BPD with profound inflammation and injury, whereas clinical improvements shifted disease pathology towards a "new" BPD in which arrest of lung maturation predominates. Future studies need to evaluate the utility of MSC-based therapies in animal models resembling the "new" BPD though promising in vitro evidence suggests that MSCs do possess the potential to stimulate lung maturation. Furthermore, we address the mode-of-action of MSC-based therapies with regard to lung development and inflammation/fibrosis. Their therapeutic efficacy is mainly attributed to an enhancement of regeneration and immunomodulation due to paracrine effects. In addition, we discuss current improvement strategies by genetic modifications or precondition of MSCs to enhance their therapeutic efficacy which could also prove beneficial for BPD therapies