EPITHELIX

Evaluation of Compound Efficacy for Treating Cystic Fibrosis

Aims:

  1. Evaluation of Corrector, Activator or Potentiator of mutated CFTR on human airway epithelium from Cystic Fibrosis donors (MucilAir™-CF)
  2. Evaluation of restore of mucociliary clearance on human airway epithelium from Cystic Fibrosis donors (MucilAir™-CF)

Strength of Epithelix:

Epithelix has a large collection of CF cells with well characterized genotypes established by certified laboratories. MucilAir™-CF replicates the major phenotypes of CF diseases: absence of chloride current, impaired muco-ciliary clearance, etc… Epithelix possesses the most advanced equipments and expertise for studying the Cystic Fibrosis diseases. Epithelix provides the following services:

A. Evaluation of Corrector, Activator or Potentiator of delta-F508 CFTR on human airway epithelium from Cystic Fibrosis donors (MucilAir™-CF)

Cystic fibrosis is a disease caused by mutations of a gene called Cystic Fibrosis Transmembrane Regulator (CFTR). CFTR is a cyclic AMP regulated chloride channel. The most frequent mutation (70% of the patients) is homozygous delta-F508. Instead being located on the apical surface of the differentiated airway epithelium, the mutated CFTR is trapped in the Endoplasmic Reticulum (ER). As consequence, the secretion of the chloride is defective, leading to abnormal mucociliary clearance, chronic bacterial infection and inflammation. Therefore, theoretically the most effectively means to treat the CF disease is to restore/improve the function of the mutated CFTR. Depending on the effect of the drugs, the drug candidates could be classified into 3 classes:

  1. Corrector, which can help the mutated CFTR to escape from the ER and reach the cytoplasmic membrane.
  2. Activator, which can directly activate normal and/or the mutated CFTR when added to the buffer.
  3. Potentiator, which can increase the amplitude/duration of CFTR activation by another activator.

In order to monitor the ion channel activity of CFTR, a special apparatus to record ion channel currents called Ussing chambers could be used. Epithelix is equipped with a modified Ussing chamber commercialized by Physiologic Instrument (EasyMount system, VCC-MC 8 channel, Acquire and analyses software). When trimmed, the Transwell Costar inserts can be easily placed into the chamber with EasyMount Inserts. Using different experimental schema, one could assess the effects of the three distinct classes of molecules.

Figure: Examples of activators, potentiators

B. Evaluation of restore of mucociliary clearance on human airway epithelium from Cystic Fibrosis donors (MucilAir™-CF)

One of the main problems in the pathology of the cystic fibrosis is the poor effectiveness of the mucociliary clearance. It leads inevitably to chronic infections of the lung with pathogen (virus and especially bacteria). With recurrent treatments with antibiotics, the bacteria become more and more resistant to antibiotics available on the market. No matter what is the underlying action mechanism of the drug, if it could improve the mucociliary clearance, it might be effective in treating CF disease. Therefore, we have developed a protocol allowing quantifying the efficacy of drugs on the mucociliary clearance.

The mucociliary clearance is monitored using a Ds-5mc camera (Nikon) connected to a DMIRE2 microscope (Leica). Microbeads of 5 μm are added onto the apical surface of the MucilAir™ (CF or Normal) pre-incubated or not with the drug. Then, 1 minute movies showing the movement of the small beads are taken and analyzed using the imaging software Image Pro Plus (Mediacy). The movement of the beads is tracked and velocity of each particle is calculated in order to know the speed of the mucociliary clearance. For these experiments, CF epithelia will be pre-incubated during 48 hours with a candidate drug before evaluating the mucociliary clearance.

Figure: This graph summarizes the results obtained on mucociliary clearance before and after addition of microbeads diluted into a solution of Compound X on MucilAir™-CF. The results reported here correspond to the average velocities obtained on 9 movies recorded on 3 independent inserts. Error bars corresponds to the SEM. Compound X has the capability to immediately restore the mucociliary clearance of MucilAir™-CF. The beneficial effect of compound X is observed within the first minute, however, we have observed a greater effect starting from 20 minutes. This enhanced effect reached a maximum after 120 minutes. The effect of compound X persists during the times tested (48 hours) but the effects are less pronounced than those observed at 120 minutes time point. The mucociliary clearance of MucilAir™-CF, without any treatment, was null in the tested conditions.

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