Cyclic AMP effectors in African trypanosomes revealed by genome-scale RNA interference library screening for resistance to the phosphodiesterase inhibitor CpdA

One of the most promising new targets for trypanocidal drugs to emerge in recent years is the cyclic AMP (cAMP) phosphodiesterase (PDE) activity encoded by TbrPDEB1 and TbrPDEB2. These genes were genetically confirmed as essential, and a high-affinity inhibitor, CpdA, displays potent antitrypanosomal activity. To identify effectors of the elevated cAMP levels resulting from CpdA action and, consequently, potential sites for adaptations giving resistance to PDE inhibitors, resistance to the drug was induced. Selection of mutagenized trypanosomes resulted in resistance to CpdA as well as cross-resistance to membrane-permeable cAMP analogues but not to currently used trypanocidal drugs. Resistance was not due to changes in cAMP levels or in PDEB genes. A second approach, a genome-wide RNA interference (RNAi) library screen, returned four genes giving resistance to CpdA upon knockdown. Validation by independent RNAi strategies confirmed resistance to CpdA and suggested a role for the identified cAMP Response Proteins (CARPs) in cAMP action. CARP1 is unique to kinetoplastid parasites and has predicted cyclic nucleotide binding-like domains, and RNAi repression resulted in >100-fold resistance. CARP2 and CARP4 are hypothetical conserved proteins associated with the eukaryotic flagellar proteome or with flagellar function, with an orthologue of CARP4 implicated in human disease. CARP3 is a hypothetical protein, unique to Trypanosoma. CARP1 to CARP4 likely represent components of a novel cAMP signaling pathway in the parasite. As cAMP metabolism is validated as a drug target in Trypanosoma brucei, cAMP effectors highly divergent from the mammalian host, such as CARP1, lend themselves to further pharmacological development.

Medienart:

E-Artikel

Erscheinungsjahr:

2013

Erschienen:

2013

Enthalten in:

Zur Gesamtaufnahme - volume:57

Enthalten in:

Antimicrobial agents and chemotherapy - 57(2013), 10 vom: 03. Okt., Seite 4882-93

Sprache:

Englisch

Beteiligte Personen:

Gould, Matthew K [VerfasserIn]
Bachmaier, Sabine [VerfasserIn]
Ali, Juma A M [VerfasserIn]
Alsford, Sam [VerfasserIn]
Tagoe, Daniel N A [VerfasserIn]
Munday, Jane C [VerfasserIn]
Schnaufer, Achim C [VerfasserIn]
Horn, David [VerfasserIn]
Boshart, Michael [VerfasserIn]
de Koning, Harry P [VerfasserIn]

Links:

Volltext

Themen:

Cyclic AMP
E0399OZS9N
Journal Article
Phosphodiesterase Inhibitors
Protozoan Proteins
Research Support, Non-U.S. Gov't
Trypanocidal Agents

Anmerkungen:

Date Completed 09.04.2014

Date Revised 15.11.2023

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1128/AAC.00508-13

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM229381049