L28- Cf 2 Flashcards
How many are carriers for CFTR mutation
1 in 25
What does CFTR mean
Cf transmembrane conductance regulatory
What does 7q31.2 mean
CFTR is on chr 7, long P arm, at region 3, band 1 and subband 2
How long is it
189kb and 1480 aa
What % of mutations are missense (change in aa)
40%
What is the most common mutation and what class is it
Phe508 deletion which is a class 2 because it doesn’t get trafficked from er to the membrane due to incorrect folding
What % are the gly551asp mutation
3% (glycine change to aspartic acid)
What type of class is this
Class 3 because it gets trafficked to the membrane but reduced channel opening and gating activity
What is class 1 and what’s it caused by
No mrna or protein produced due to premature stop codon or splicing defects
What is class 2
Proteins not trafficked to membrnae
What is class 3 and 4
gating issues for class 3 and class 4 is issues / alteration in conductance
What are the rare class 5 and 6 mutations
Less CFTR protein is produced and class 6 is abnormally high turnover of CFTR on cell membrane
What secondary messenger activates the CFTR anion channel
Camp via pka phos activation of CFTR
What is CFTR gated by
Atp gated
What conductance does it usually cause
Cl conductance but can also be thiocyanate and hco
What are the 5 domains
2 membrane spinning domains (pore forming MSD)
2 nucleotide binding domains NBD(atp binding and hydrolysis)
1 regulatory R domain (what gets phos by pka)
What is atp and phosphorylation needed for (Shepard and Walsh 1999)
Needed for channel activation, gating activity channel opening or closing via hydrolysis
Which article discusses why phe508 doesn’t get trafficked to membrane
Scott- ward 2009
What recognises the mutation and targets it for proteasomes deg
Er quality control system erqc
What binds to the phe508 mutation and allows erqc recognition
Hsp70
Which domain does phe508 occur in same as gly551asp
Nbd1
How does the gly change to asp affect gating as a class 3 mutation
Occurs in one of the atp binding sites so atp can’t bind and affects gating activity (sheppard and Walsh 1999)
Which other channels other than enac does CFTR regulate
Cl channels eg ORCC, CaCC (outward rectifying)
K channels
Anion exchanger SLC26 family
Through what domain of CFTR do some have direct interaction
PDZ domain
Is CFTR expressed evenly on all epi cells
No. Expressed on ionocytes a lot more which is a therapeutic target
Which article talks about other channels and the asl homeostasis
Haq et Al 2015
Which 3 channels are important for asl homeostasis which are all modulated by CFTR
CaCC, slc26a, enac
What are the 2 layers of asl
Periciliary layer pcl which is kept water for cilia movement
Then gel-mucin made mucus on top
In normal airways not cf, which protein regulates enac so no na hyper absorption
Splunc1
Which conditions is this lost in
Low ph/acidic ph eg when CFTR doesn’t work
What does water leaving the pcl mean
Compression of the ciliary layer as mucus builds up
What does slc26a do for homeostasis
Uses the Cl/HCO exchanger it has to secrete HCO for ph regulation therefore increasing splunc1 action and maintains bacterial barrier
Which article discusses in copd lectures suggested which things cause mucus hypersecretion in cf too
Kim 2013
Th2,th17, infections, NE, oxidative stress
How does mucus actually increase
Goblet cell hyperplasia and submucosal gland hypertrophy
Which 4 effects does acidification in cf cause
Mucus misfolding/ viscosity
Amp/antimicrobial impaired
reduced sphingipid metabolism
Reduced control of ion transport (splunc 1)
Which spingolipud accumulates in cf due to the ph affecting metabolism enzymes (brodlie et Al 2010)
Ceramide (
What does ceramide accumulation do (brodlie 2010)
Increases chronic inflammation through death of airway epi cells, proinflam cytokines and susceptibility to pa
Which infections seen in younger cf patients
S aureus mainly but also hinfleunzae
Pa is in older
What % does mrsa affect in cf which is more virulent as methicillin resistant
5-15%
What sorts of things can if sa is pathogenic do
Damage to epi cells, inflammation and infiltration of other pathognes
When is fev1 worse than just if cf have sa alone (schwerdt et Al 2018)
If co colonised with pa so could be synergistic
When is sa most common in cf (schwerdt 2018)
7-19years (schwerdt 2018)
Which article discusses more saureus and airway epi cells
Silva 2004
Which antimicrobial things needed to fight saureus
Lysozymes, lactoferrins, slpI
How can saureus induce apoptosis and necrosis in epi cells causing more inflammation and damage
Has an a-toxin which forms pores in membrane by cleaving phospholipids
Which pathways of inflammation can saureus and pa induce
Nfkb and il8
Which article discusses cf, pa and inflammation
Hart 2002
Which th response does pa trigger which was linked to mucus hypersecretion in Kim 2013
Th2
Why would the f508 deletion reduce clearance of pa
Because usually internalised through the cf and then cleared in the cell
Which exo polysaccharides do pa produce which can block neutrophil protection
Alginate
Which process of signalling allows pa to produce biofilms and also alginate (virulence)
Quorum sensing
What do they release which causes damage to airway and low fev1
Proteases, elastases, lipases
Which liquid in lungs do they reduce causing collapse
Surfactant
How do they increase during inflammation/ chronic inflammation (malhotra 2019)
Aea nitrates which build up during inflammation
Which bacteria is harder to treat than pa and saureus
Non tuberculous mycobacterium
Why would someone with ntm not have a transplant
Cannot be immunosuppressed as ntm severely reduces lung function
Which types of remodelling can neutrophilic inflammation cause
Bronchitis and bronchiectasis in cf (progressive and persistent inflammation)
Other than neutrophils what else is seen in cf inflammation and remodelling
TNFa, il 1b, il17, il6, il8
What % of wbc are neutrophils
60%
Other than hyperplasia of goblet cells why other remodelling occurs in cf
Thickening of reticular basement membrane and smooth muscle of airway due to hyperplasia
What is the reticular basement membrane
The layer under epi cells before the submucosa begins then smooth muscle
Which cytokines associated with cf can cause basal cell hyperplasia (thick bm) (adam et Al 2015)
Il1b, il6, tnfa
Which part of pa can cause goblet cell hyperplasia
Lps
What are Ali cell cultures
Airway liquid interface cultures
Samples from nose of lower airways via a brush sample taken to study airways of cf
Which equipment is used to measure ion transport/ study channels in the Ali cultures
Ussing chamber
Why is a gradient present / polarised cells in epi cells
Polarised between the apical and baso lateral site
What activates CFTR electrical movement in ussing chamber if functional
Foreskolin
What would happen if a CFTR inhibitor added if functional
Massive drop in electrical movement
How is this different to if not functional eg Cf patients
No electrical movement change when foreskolin or the inhibitor added through CFTR
Which Cl channel works for both cf and non cf seen when utp added to ussing chamber showing potential therapy
Tmem16a
