scholarly journals Progress Toward The Synthesis Of Labeled Derivatives Of The Cystic Fibrosis Drug Ivacaftor

2021 ◽  
Author(s):  
Salma Elmallah
Keyword(s):  
Cystic Fibrosis ◽  
Plasma Membrane ◽  
Genetic Diseases ◽  
Early Death ◽  
Open Probability ◽  
Gene Encoding ◽  
Short Period ◽  
Cftr Mutations ◽  
Cftr Protein ◽  
Orally Bioavailable

Cystic fibrosis (CF) is one of the most common genetic diseases, affecting approximately 70,000 people worldwide causing severe complications and often leading to early death. CF is caused by a mutation in the gene encoding for the cystic fibrosis transmembrane conductance regulator (CFTR) protein which is responsible for fluid and ion transport through epithelial membranes maintaining the formation of a thin slippery mucous layer. CFTR mutations either lead to a trafficking defect where the CFTR protein does not reach the plasma membrane or a gating defect where CFTR protein at the plasma membrane does not function properly. Treatment of cystic fibrosis usually addresses the symptoms to overcome the complications of the disease such as pneumonia, lung infections, pancreatitis, maldigestion and infertility. Vertex pharmaceuticals has been interested in developing small molecules that have the ability to interact with mutated CFTR proteins, aiding in their delivery to the cell membrane and/or restoring their channel function. VX-770 is an orally bioavailable potentiator that has the ability to improve the gating activity and increasing the open probability of CFTR protein in patients carrying the G551D mutation. VX770, Ivacaftor, was recently approved by the US FDA after showing very good improvements in the lung function in CF patients with good safety profile. Our research is focusing on the synthesis of VX770 under mild conditions and formation of labeled derivatives to help in the understanding of its exact mode of action. Different methods were developed toward the synthesis of the two main components, LHS and RHS, of VX770 by using less harsh conditions for a short period of time. We were successfully able to make two photoaffinity labeled derivatives, aryl azide and benzophenone derivatives, which will be beneficial in tracking the drug molecule and revealing the exact site of interaction between the drug and the protein. Synthesis of VX770 fragments was is another focus of interest in our research as they will provide us with information about the best positions for further derivatization.

scholarly journals Progress Toward The Synthesis Of Labeled Derivatives Of The Cystic Fibrosis Drug Ivacaftor

2021 ◽  
Author(s):  
Salma Elmallah
Keyword(s):  
Cystic Fibrosis ◽  
Plasma Membrane ◽  
Genetic Diseases ◽  
Early Death ◽  
Open Probability ◽  
Gene Encoding ◽  
Short Period ◽  
Cftr Mutations ◽  
Cftr Protein ◽  
Orally Bioavailable

Cystic fibrosis (CF) is one of the most common genetic diseases, affecting approximately 70,000 people worldwide causing severe complications and often leading to early death. CF is caused by a mutation in the gene encoding for the cystic fibrosis transmembrane conductance regulator (CFTR) protein which is responsible for fluid and ion transport through epithelial membranes maintaining the formation of a thin slippery mucous layer. CFTR mutations either lead to a trafficking defect where the CFTR protein does not reach the plasma membrane or a gating defect where CFTR protein at the plasma membrane does not function properly. Treatment of cystic fibrosis usually addresses the symptoms to overcome the complications of the disease such as pneumonia, lung infections, pancreatitis, maldigestion and infertility. Vertex pharmaceuticals has been interested in developing small molecules that have the ability to interact with mutated CFTR proteins, aiding in their delivery to the cell membrane and/or restoring their channel function. VX-770 is an orally bioavailable potentiator that has the ability to improve the gating activity and increasing the open probability of CFTR protein in patients carrying the G551D mutation. VX770, Ivacaftor, was recently approved by the US FDA after showing very good improvements in the lung function in CF patients with good safety profile. Our research is focusing on the synthesis of VX770 under mild conditions and formation of labeled derivatives to help in the understanding of its exact mode of action. Different methods were developed toward the synthesis of the two main components, LHS and RHS, of VX770 by using less harsh conditions for a short period of time. We were successfully able to make two photoaffinity labeled derivatives, aryl azide and benzophenone derivatives, which will be beneficial in tracking the drug molecule and revealing the exact site of interaction between the drug and the protein. Synthesis of VX770 fragments was is another focus of interest in our research as they will provide us with information about the best positions for further derivatization.

scholarly journals Therapeutic Approaches for Patients with Cystic Fibrosis Not Eligible for Current CFTR Modulators

Cells ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2793
Author(s):  
Isabelle Fajac ◽  
Isabelle Sermet
Keyword(s):  
Cystic Fibrosis ◽  
Protein Function ◽  
Protein A ◽  
Autosomal Recessive Disorder ◽  
New Drugs ◽  
Gene Encoding ◽  
Disease Modifying Drugs ◽  
Cftr Mutations ◽  
Cftr Protein ◽  
Cftr Modulators

Cystic fibrosis is a severe autosomal recessive disorder caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene encoding the CFTR protein, a chloride channel expressed in many epithelial cells. New drugs called CFTR modulators aim at restoring the CFTR protein function, and they will benefit many patients with cystic fibrosis in the near future. However, some patients bear rare mutations that are not yet eligible for CFTR modulators, although they might be amenable to these new disease-modifying drugs. Moreover, more than 10% of CFTR mutations do not produce any CFTR protein for CFTR modulators to act upon. The purpose of this review is to provide an overview of different approaches pursued to treat patients bearing mutations ineligible for CFTR modulators. One approach is to broaden the numbers of mutations eligible for CFTR modulators. This requires developing strategies to evaluate drugs in populations bearing very rare genotypes. Other approaches aiming at correcting the CFTR defect develop new mutation-specific or mutation-agnostic therapies for mutations that do not produce a CFTR protein: readthrough agents for nonsense mutations, nucleic acid-based therapies, RNA- or DNA-based, and cell-based therapies. Most of these approaches are in pre-clinical development or, for some of them, early clinical phases. Many hurdles and challenges will have to be solved before they can be safely translated to patients.

scholarly journals Molecular pathology of the R117H cystic fibrosis mutation is explained by loss of a hydrogen bond

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Márton A Simon ◽  
László Csanády
Keyword(s):  
Cystic Fibrosis ◽  
Hydrogen Bond ◽  
Molecular Pathology ◽  
Atp Hydrolysis ◽  
Salt Water ◽  
Anion Channel ◽  
Open Probability ◽  
Binding Domains ◽  
State Dependent ◽  
Cftr Mutations

The phosphorylation-activated anion channel CFTR is gated by an ATP hydrolysis cycle at its two cytosolic nucleotide binding domains, and is essential for epithelial salt-water transport. A large number of CFTR mutations cause cystic fibrosis. Since recent breakthrough in targeted pharmacotherapy, CFTR mutants with impaired gating are candidates for stimulation by potentiator drugs. Thus, understanding the molecular pathology of individual mutations has become important. The relatively common R117H mutation affects an extracellular loop, but nevertheless causes a strong gating defect. Here we identify a hydrogen bond between the side chain of arginine 117 and the backbone carbonyl group of glutamate 1124 in the cryo-electronmicroscopic structure of phosphorylated, ATP-bound CFTR. We address the functional relevance of that interaction for CFTR gating using macroscopic and microscopic inside-out patch-clamp recordings. Employing thermodynamic double-mutant cycles, we systematically track gating-state dependent changes in the strength of the R117-E1124 interaction. We find that the H-bond is formed only in the open state, but neither in the short-lived "flickery" nor in the long-lived 'interburst' closed state. Loss of this H-bond explains the strong gating phenotype of the R117H mutant, including robustly shortened burst durations and strongly reduced intraburst open probability. The findings may help targeted potentiator design.

scholarly journals Cytoskeleton regulators CAPZA2 and INF2 associate with CFTR to control its plasma membrane levels under EPAC1 activation

2020 ◽  
Vol 477 (13) ◽  
pp. 2561-2580
Author(s):  
João D. Santos ◽  
Francisco R. Pinto ◽  
João F. Ferreira ◽  
Margarida D. Amaral ◽  
Manuela Zaccolo ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Protein A ◽  
Bioinformatic Analysis ◽  
Apical Surface ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Gene Encoding ◽  
Cftr Protein ◽  
Related Proteins ◽  
Cystic Fibrosis Transmembrane

Cystic Fibrosis (CF), the most common lethal autosomic recessive disorder among Caucasians, is caused by mutations in the gene encoding the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) protein, a cAMP-regulated chloride channel expressed at the apical surface of epithelial cells. Cyclic AMP regulates both CFTR channel gating through a protein kinase A (PKA)-dependent process and plasma membane (PM) stability through activation of the exchange protein directly activated by cAMP1 (EPAC1). This cAMP effector, when activated promotes the NHERF1:CFTR interaction leading to an increase in CFTR at the PM by decreasing its endocytosis. Here, we used protein interaction profiling and bioinformatic analysis to identify proteins that interact with CFTR under EPAC1 activation as possible regulators of this CFTR PM anchoring. We identified an enrichment in cytoskeleton related proteins among which we characterized CAPZA2 and INF2 as regulators of CFTR trafficking to the PM. We found that CAPZA2 promotes wt-CFTR trafficking under EPAC1 activation at the PM whereas reduction of INF2 levels leads to a similar trafficking promotion effect. These results suggest that CAPZA2 is a positive regulator and INF2 a negative one for the increase of CFTR at the PM after an increase of cAMP and concomitant EPAC1 activation. Identifying the specific interactions involving CFTR and elicited by EPAC1 activation provides novel insights into late CFTR trafficking, insertion and/or stabilization at the PM and highlighs new potential therapeutic targets to tackle CF disease.

scholarly journals Impact of Altered Gut Microbiota and Its Metabolites in Cystic Fibrosis

Metabolites ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 123
Author(s):  
Aravind Thavamani ◽  
Iman Salem ◽  
Thomas J. Sferra ◽  
Senthilkumar Sankararaman
Keyword(s):  
Cystic Fibrosis ◽  
Genetic Disorder ◽  
Vital Role ◽  
Immune Functions ◽  
Gene Encoding ◽  
Gut Dysbiosis ◽  
Multiple Organs ◽  
Fluid Regulation ◽  
Cftr Protein ◽  
Cystic Fibrosis Transmembrane

Cystic fibrosis (CF) is the most common lethal, multisystemic genetic disorder in Caucasians. Mutations in the gene encoding the cystic fibrosis transmembrane regulator (CFTR) protein are responsible for impairment of epithelial anionic transport, leading to impaired fluid regulation and pH imbalance across multiple organs. Gastrointestinal (GI) manifestations in CF may begin in utero and continue throughout the life, resulting in a chronic state of an altered intestinal milieu. Inherent dysfunction of CFTR leads to dysbiosis of the gut. This state of dysbiosis is further perpetuated by acquired factors such as use of antibiotics for recurrent pulmonary exacerbations. Since the gastrointestinal microbiome and their metabolites play a vital role in nutrition, metabolic, inflammatory, and immune functions, the gut dysbiosis will in turn impact various manifestations of CF—both GI and extra-GI. This review focuses on the consequences of gut dysbiosis and its metabolic implications on CF disease and possible ways to restore homeostasis.

scholarly journals Evidence for the Involvement of Lipid Rafts and Plasma Membrane Sphingolipid Hydrolases in Pseudomonas aeruginosa Infection of Cystic Fibrosis Bronchial Epithelial Cells

2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Domitilla Schiumarini ◽  
Nicoletta Loberto ◽  
Giulia Mancini ◽  
Rosaria Bassi ◽  
Paola Giussani ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Plasma Membrane ◽  
Epithelial Cells ◽  
Inflammatory Response ◽  
Lipid Rafts ◽  
Wide Spectrum ◽  
Bronchial Epithelial Cells ◽  
Gene Encoding ◽  
Bronchial Epithelial

Cystic fibrosis (CF) is the most common autosomal genetic recessive disease caused by mutations of gene encoding for the cystic fibrosis transmembrane conductance regulator. Patients with CF display a wide spectrum of symptoms, the most severe being chronic lung infection and inflammation, which lead to onset of cystic fibrosis lung disease. Several studies indicate that sphingolipids play a regulatory role in airway inflammation. The inhibition and downregulation of GBA2, the enzyme catabolizing glucosylceramide to ceramide, are associated with a significant reduction of IL-8 production in CF bronchial epithelial cells. Herein, we demonstrate that GBA2 plays a role in the proinflammatory state characterizing CF cells. We also report for the first time that Pseudomonas aeruginosa infection causes a recruitment of plasma membrane-associated glycosphingolipid hydrolases into lipid rafts of CuFi-1-infected cells. This reorganization of cell membrane may be responsible for activation of a signaling cascade, culminating in aberrant inflammatory response in CF bronchial epithelial cells upon bacterial infection. Taken together, the presented data further support the role of sphingolipids and their metabolic enzymes in controlling the inflammatory response in CF.

scholarly journals The Distribution and Role of the CFTR Protein in the Intracellular Compartments

Membranes ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 804
Author(s):  
Agnieszka Lukasiak ◽  
Miroslaw Zajac
Keyword(s):  
Cystic Fibrosis ◽  
Physiological Role ◽  
Anion Channel ◽  
Fluid Secretion ◽  
Hereditary Disease ◽  
Gene Encoding ◽  
Pharmacological Agents ◽  
Intracellular Compartments ◽  
Cftr Protein

Cystic fibrosis is a hereditary disease that mainly affects secretory organs in humans. It is caused by mutations in the gene encoding CFTR with the most common phenylalanine deletion at position 508. CFTR is an anion channel mainly conducting Cl− across the apical membranes of many different epithelial cells, the impairment of which causes dysregulation of epithelial fluid secretion and thickening of the mucus. This, in turn, leads to the dysfunction of organs such as the lungs, pancreas, kidney and liver. The CFTR protein is mainly localized in the plasma membrane; however, there is a growing body of evidence that it is also present in the intracellular organelles such as the endosomes, lysosomes, phagosomes and mitochondria. Dysfunction of the CFTR protein affects not only the ion transport across the epithelial tissues, but also has an impact on the proper functioning of the intracellular compartments. The review aims to provide a summary of the present state of knowledge regarding CFTR localization and function in intracellular compartments, the physiological role of this localization and the consequences of protein dysfunction at cellular, epithelial and organ levels. An in-depth understanding of intracellular processes involved in CFTR impairment may reveal novel opportunities in pharmacological agents of cystic fibrosis.

scholarly journals Elexacaftor is a CFTR potentiator and acts synergistically with ivacaftor during acute and chronic treatment

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ciaran A. Shaughnessy ◽  
Pamela L. Zeitlin ◽  
Preston E. Bratcher
Keyword(s):  
Cystic Fibrosis ◽  
Early Death ◽  
New Combination ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Acute And Chronic Treatment ◽  
Cftr Mutations ◽  
Small Molecule Modulators ◽  
Cystic Fibrosis Transmembrane

AbstractCystic fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR), which lead to early death due to progressive lung disease. The development of small-molecule modulators that directly interact with CFTR to aid in protein folding (“correctors”) and/or increase channel function (“potentiators”) have proven to be highly effective in the therapeutic treatment of CF. Notably, incorporation of the next-generation CFTR corrector, elexacaftor, into a triple combination therapeutic (marketed as Trikafta) has shown tremendous clinical promise in treating CF caused by F508del-CFTR. Here, we report on a newly-described role of elexacaftor as a CFTR potentiator. We explore the acute and chronic actions, pharmacology, and efficacy of elexacaftor as a CFTR potentiator in restoring function to multiple classes of CFTR mutations. We demonstrate that the potentiating action of elexacaftor exhibits multiplicative synergy with the established CFTR potentiator ivacaftor in rescuing multiple CFTR class defects, indicating that a new combination therapeutic of ivacaftor and elexacaftor could have broad impact on CF therapies.

scholarly journals Overcoming Immunological Challenges to Helper-Dependent Adenoviral Vector-Mediated Long-Term CFTR Expression in Mouse Airways

Genes ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 565
Author(s):  
Huibi Cao ◽  
Rongqi Duan ◽  
Jim Hu
Keyword(s):  
Cystic Fibrosis ◽  
Gene Therapy ◽  
Immune Responses ◽  
Mouse Lung ◽  
Host Immune Responses ◽  
Gene Therapy Vectors ◽  
Cftr Mutations ◽  
Cftr Protein ◽  
Cluster Of Differentiation ◽  
Mouse Lungs

Cystic Fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, and CF patients require life-long treatment. Although CFTR modulators show a great potential for treating most CF patients, some individuals may not tolerate the treatment. In addition, there is no effective therapy for patients with some rare CFTR mutations, such as class I CF mutations, which lead to a lack of CFTR protein production. Therefore, other therapeutic strategies, such as gene therapy, have to be investigated. Currently, immune responses to gene therapy vectors and transgene products are a major obstacle to applying CF gene therapy to clinical applications. In this study, we examined the effects of cyclophosphamide on the modulation of host immune responses and for the improvement of the CFTR transgene expression in the repeated delivery of helper-dependent adenoviral (HD-Ad) vectors to mouse lungs. We have found that cyclophosphamide significantly decreased the expression of T cell genes, such as CD3 (cluster of differentiation 3) and CD4, and reduced their infiltration into mouse lung tissues. We have also found that the levels of the anti-adenoviral antibody and neutralizing activity as well as B-cell infiltration into the mouse lung tissues were significantly reduced with this treatment. Correspondingly, the expression of the human CFTR transgene has been significantly improved with cyclophosphamide administration compared to the group with no treatment. These data suggest that the sustained expression of the human CFTR transgene in mouse lungs through repeated vector delivery can be achieved by transient immunosuppression.

scholarly journals Molecular pathology of a cystic fibrosis mutation is explained by loss of a hydrogen bond

2021 ◽  
Author(s):  
Márton A Simon ◽  
LászlÓ Csanády
Keyword(s):  
Cystic Fibrosis ◽  
Hydrogen Bond ◽  
Molecular Pathology ◽  
Atp Hydrolysis ◽  
Salt Water ◽  
Anion Channel ◽  
Open Probability ◽  
Binding Domains ◽  
State Dependent ◽  
Cftr Mutations

The phosphorylation-activated anion channel CFTR is gated by an ATP hydrolysis cycle at its two cytosolic nucleotide binding domains, and is essential for epithelial salt-water transport. A large number of CFTR mutations cause cystic fibrosis. Since recent breakthrough in targeted pharmacotherapy, CFTR mutants with impaired gating are candidates for stimulation by potentiator drugs. Thus, understanding the molecular pathology of individual mutations has become important. The relatively common R117H mutation affects an extracellular loop, but nevertheless causes a strong gating defect. Here we identify a hydrogen bond between the side chain of arginine 117 and the backbone carbonyl group of glutamate 1124 in the cryo-electronmicroscopic structure of phosphorylated, ATP-bound CFTR. We address the functional relevance of that interaction for CFTR gating using macroscopic and microscopic inside-out patch-clamp recordings. Employing thermodynamic double-mutant cycles, we systematically track gating-state dependent changes in the strength of the R117-E1124 interaction. We find that the H-bond is formed only in the open state, but neither in the short-lived "flickery" nor in the long-lived "interburst" closed state. Loss of this H-bond explains the entire gating phenotype of the R117H mutant, including robustly shortened burst durations and strongly reduced intraburst open probability. The findings may help targeted potentiator design.

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