Cryptosporidium parvum: effect of multi-drug reversing agents on the expression and function of ATP-binding cassette transporters.
In the present study, the gene expression of three multidrug resistance (MDR) and resistance-associated protein (MRP) transport proteins or efflux pumps was characterized and the phenotypic evidence for such pumps was demonstrated in cultured Madin-Darby canine kidney (MDCK) cells. A gradient for the fluorescent probe calcein was established between parasite and host cell suggestive of a parasite extrusion pump at the parasite-host interface. This gradient was decreased in a glucose-free medium containing 2-deoxyglucose or 3-O-methylglucose, by probenecid, and by the isoflavonoid, narigenin, suggesting that the calcein extrusion was energy-dependent and involved an MRP-like pump. While neither MDR or MRP inhibiters significantly affected transcript levels of any of the ABC transporters, transcript levels of the Cryptosporidium parvum ABC protein (CpABC1), an MRP transporter, were consistently expressed 4 logs higher than either CpABC3 or CpABC2, suggesting a prominent role in the intracellular stages of the parasite.
Bonafonte
María-Teresa
MT
Veterans Affairs Medical Center, 1670 Clairmont Road, Decatur, GA 30033, USA.
Romagnoli
Pablo A
PA
McNair
Nina
N
Shaw
Andrew P
AP
Scanlon
Mary
M
Leitch
Gordon J
GJ
Mead
Jan R
JR
D019325:3-O-Methylglucose / Q000494:pharmacology; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000037:antagonists & inhibitors; D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D016785:Cryptosporidium parvum / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D016572:Cyclosporine / Q000494:pharmacology*; D003847:Deoxyglucose / Q000494:pharmacology; D018432:Drug Resistance, Multiple / Q000187:drug effects / Q000235:genetics; D044950:Flavanones / Q000494:pharmacology; D005452:Fluoresceins; D005456:Fluorescent Dyes; D015870:Gene Expression / Q000187:drug effects; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000037:antagonists & inhibitors; D011339:Probenecid / Q000494:pharmacology*; D014700:Verapamil / Q000494:pharmacology*
D019325:3-O-Methylglucose; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D018528:ATP-Binding Cassette Transporters; D016572:Cyclosporine; D003847:Deoxyglucose; D044950:Flavanones; D005452:Fluoresceins; D005456:Fluorescent Dyes; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D011339:Probenecid; D014700:Verapamil; C005273:naringenin; C007740:fluorexon