Anti-Inflammatory Effects of the Iron Chelator, DIBI, in Experimental Acute Lung Injury.

Iron plays a critical role in the immune response to inflammation and infection due to its role in the catalysis of reactive oxygen species (ROS) through the Haber-Weiss and Fenton reactions. However, ROS overproduction can be harmful and damage healthy cells. Therefore, iron chelation represents an innovative pharmacological approach to limit excess ROS formation and the related pro-inflammatory mediator cascades.

Lung-Protective Ventilation Attenuates Mechanical Injury While Hypercapnia Attenuates Biological Injury in a Rat Model of Ventilator-Associated Lung Injury.

Lung-protective mechanical ventilation is known to attenuate ventilator-associated lung injury (VALI), but often at the expense of hypoventilation and hypercapnia. It remains unclear whether the main mechanism by which VALI is attenuated is a product of limiting mechanical forces to the lung during ventilation, or a direct biological effect of hypercapnia. Acute lung injury (ALI) was induced in 60 anesthetized rats by the instillation of 1.

VIP reduction in the pancreas of F508del homozygous CF mice and early signs of Cystic Fibrosis Related Diabetes (CFRD).

Vasoactive intestinal peptide (VIP), a 28-amino acid neuropeptide with potent anti-inflammatory, bronchodilatory and immunomodulatory functions, is secreted by intrinsic neurons innervating all exocrine glands, including the pancreas, in which it exerts a regulatory function in the secretion of insulin and glucagon. Cystic fibrosis-related diabetes (CFRD) is the most common co-morbidity associated with cystic fibrosis (CF), impacting approximately 50% of adult patients. We recently demonstrated a 50% reduction of VIP abundance in the lungs, duodenum and sweat glands of C57Bl/6 CF mice homozygous for the F508del-CFTR disease-causing mutation.

Disrupted local innervation results in less VIP expression in CF mice tissues.

Vasoactive Intestinal Peptide (VIP) is the major physiological agonist of the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) chloride channel activity. VIP functions as a neuromodulator and neurotransmitter secreted by neurons innervating all exocrine glands. VIP is also a potent vasodilator and bronchodilator that regulates exocrine gland secretions, contributing to local innate defense by stimulating the movement of water and chloride transport across intestinal and tracheobronchial epithelia.

Changes in the R-region interactions depend on phosphorylation and contribute to PKA and PKC regulation of the cystic fibrosis transmembrane conductance regulator chloride channel.

The CFTR chloride channel is regulated by phosphorylation at PKA and PKC consensus sites within its regulatory region (R-region) through a mechanism, which is still not completely understood. We used a split-CFTR construct expressing the N-term-TMD1-NBD1 (Front Half; FH), TMD2-NBD2-C-Term (Back Half; BH), and the R-region as separate polypeptides (Split-R) in BHK cells, to investigate in situ how different phosphorylation conditions affect the R-region interactions with other parts of the protein. In proximity ligation assays, we studied the formation of complexes between the R-region and each half of the Split-CFTR.

Working to Have a Normal Life With Cystic Fibrosis in an Adherence-Driven Health Care System.

Background: Adults with cystic fibrosis (CF) must continuously manage their condition, while working for a living, and want a normal life. Adherence rates to treatments/medications are less than optimal. Existing theory offers little to explain adherence rates.

Animal Models in the Pathophysiology of Cystic Fibrosis.

Our understanding of the multiorgan pathology of cystic fibrosis (CF) has improved impressively during the last decades, but we still lack a full comprehension of the disease progression. Animal models have greatly contributed to the elucidation of specific mechanisms involved in CF pathophysiology and the development of new therapies. Soon after the cloning of the CF transmembrane conductance regulator () gene in 1989, the first mouse model was generated and this model has dominated CF research ever since.

Iron chelation as novel treatment for lung inflammation in cystic fibrosis.

Cystic fibrosis (CF) is an autosomal recessive genetic disorder that results in defective cystic fibrosis transmembrane conductance regulator (CFTR) protein expression and function in various tissues. The leading cause of CF mortality and morbidity is the progressive destruction of the lungs due to recurrent infections and chronic inflammation. CFTR defect also affects immune cells, including neutrophils, resulting in ineffective, severe and persistent inflammatory response.

Modeling cystic fibrosis disease progression in patients with the rare CFTR mutation P67L.

Background: The progression of cystic fibrosis (CF) in patients with the rare mutation P67L was examined to determine if it induced a milder form of CF compared to the common severe ΔF508 mutation.

Methods: Parameters of lung function, level of bacterial infection, nutritional status and hospitalization were used to represent CF progression. Age at diagnosis and pancreatic status were used to assess CF presentation.

ClC Channels and Transporters: Structure, Physiological Functions, and Implications in Human Chloride Channelopathies.

The discovery of ClC proteins at the beginning of the 1990s was important for the development of the Cl transport research field. ClCs form a large family of proteins that mediate voltage-dependent transport of Cl ions across cell membranes. They are expressed in both plasma and intracellular membranes of cells from almost all living organisms.

The role of ghrelin in the regulation of glucose homeostasis.

Ghrelin is a 28-amino acid (aa) stomach-derived peptide discovered in 1999 as the endogenous ligand for growth hormone secretagogue-receptor (GHS-R). Ghrelin-producing cells constitute a distinct group of endocrine cells dispersed throughout the gastric mucosa and to a lesser extent in the small intestine and the endocrine pancreas. Ghrelin plasma levels rise during fasting and chronic caloric restriction to stimulate food intake and fat storage and to prevent life-threatening falls in blood glucose.

Cystic fibrosis transmembrane conductance regulator dysfunction in VIP knockout mice.

Vasoactive intestinal peptide (VIP), a neuropeptide, controls multiple functions in exocrine tissues, including inflammation, and relaxation of airway and vascular smooth muscles, and regulates CFTR-dependent secretion, which contributes to mucus hydration and local innate defense of the lung. We had previously reported that VIP stimulates the VPAC1 receptor, PKCϵ signaling cascade, and increases CFTR stability and function at the apical membrane of airway epithelial cells by reducing its internalization rate. Moreover, prolonged VIP stimulation corrects the molecular defects associated with F508del, the most common CFTR mutation responsible for the genetic disease cystic fibrosis.

VIP regulates CFTR membrane expression and function in Calu-3 cells by increasing its interaction with NHERF1 and P-ERM in a VPAC1- and PKCε-dependent manner.

Vasoactive intestinal peptide (VIP) is a topical airway gland secretagogue regulating fluid secretions, primarily by stimulating cystic fibrosis transmembrane conductance regulator (CFTR)-dependent chloride secretion that contributes to the airways innate defense mechanism. We previously reported that prolonged VIP stimulation of pituitary adenylate cyclase-activating peptide receptors (VPAC1) in airway cells enhances CFTR function by increasing its membrane stability. In the present study, we identified the key effectors in the VIP signaling cascade in the human bronchial serous cell line Calu-3.

VIP-dependent increase in F508del-CFTR membrane localization is mediated by PKCε.

The most common cystic fibrosis causing mutation F508del induces early degradation and reduced trafficking of cystic fibrosis transmembrane conductance regulator (CFTR) chloride channels to the apical membrane of epithelial cells. In the human nasal epithelial cells JME/CF15, we previously reported that vasoactive intestinal peptide (VIP) exposure corrects trafficking and membrane insertion of functional F508del-CFTR channels at 37°C. Correction of trafficking was PKA dependent, whereas enhanced membrane localization involved PKC.

Rescue of functional F508del cystic fibrosis transmembrane conductance regulator by vasoactive intestinal peptide in the human nasal epithelial cell line JME/CF15.

F508del is the most common cystic fibrosis-causing mutation that induces early degradation and poor trafficking of cystic fibrosis transmembrane conductance regulator (CFTR) chloride channels to the apical membrane of epithelial cells. Our previous work in bronchial serous cells showed that vasoactive intestinal peptide (VIP) stimulation of the VPAC(1) receptor enhances CFTR-dependent chloride secretion by increasing its membrane insertion by a protein kinase C (PKC)-dependent pathway. In the present study, we investigated the effect of VIP on F508del-CFTR activity and membrane insertion in the human nasal epithelial cell line JME/CF15, which also expresses the VPAC(1) receptor.

PKC phosphorylation modulates PKA-dependent binding of the R domain to other domains of CFTR.

Activity of the CFTR channel is regulated by phosphorylation of its regulatory domain (RD). In a previous study, we developed a bicistronic construct called DeltaR-Split CFTR, which encodes the front and back halves of CFTR as separate polypeptides without the RD. These fragments assemble to form a constitutively active CFTR channel.

Vasoactive intestinal peptide increases cystic fibrosis transmembrane conductance regulator levels in the apical membrane of Calu-3 cells through a protein kinase C-dependent mechanism.

Noncholinergic neurons contribute to innate airway defenses by releasing vasoactive intestinal peptides (VIP), which stimulates the submucosal glands to produce a bicarbonate-rich fluid containing mucins and antimicrobial factors. VIP elevates cAMP and activates cystic fibrosis transmembrane conductance regulator (CFTR) channels; however, its effects on surface expression have not been investigated. We studied CFTR levels in the apical membrane of polarized Calu-3 cell monolayers, a widely used model for submucosal gland serous cells.

Phosphorylation of CFTR by PKA promotes binding of the regulatory domain.

The unphosphorylated regulatory (R) domain of the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) is often viewed as an inhibitor that is released by phosphorylation. To test this notion, we studied domain interactions using CFTR channels assembled from three polypeptides. Nucleotides encoding the R domain (aa 635-836) were replaced with an internal ribosome entry sequence so that amino- and carboxyl-terminal half-molecules would be translated from the same mRNA transcript.

Pharmacological and signaling properties of endogenous P2Y1 receptors in cystic fibrosis transmembrane conductance regulator-expressing Chinese hamster ovary cells.

The cystic fibrosis (CF) transmembrane conductance regulator (CFTR) is a cAMP-dependent Cl(-) channel that is defective in CF disease. CFTR activity has been shown to be regulated by the G(q)/phospholipase C-linked P2Y2 subtype of P2Y nucleotide receptors (P2YR) in various systems. Here, we tested whether other P2YR may exert a regulation on CFTR activity and whether CFTR may in turn exert a regulation on P2YR signaling.

Stimulatory and inhibitory protein kinase C consensus sequences regulate the cystic fibrosis transmembrane conductance regulator.

Protein kinase C (PKC) phosphorylation stimulates the cystic fibrosis transmembrane conductance regulator (CFTR) channel and enhances its activation by protein kinase A (PKA) through mechanisms that remain poorly understood. We have examined the effects of mutating consensus sequences for PKC phosphorylation and report here evidence for both stimulatory and inhibitory sites. Sequences were mutated in subsets and the mutants characterized by patch clamping.