Abstract |
The rare disease Primary Hyperoxaluria Type I (PH1) results from the deficit of liver peroxisomal alanine:glyoxylate aminotransferase (AGT), as a consequence of inherited mutations on the AGXT gene frequently leading to protein misfolding. Pharmacological chaperone (PC) therapy is a newly developed approach for misfolding diseases based on the use of small molecule ligands able to promote the correct folding of a mutant enzyme. In this report, we describe the interaction of amino-oxyacetic acid (AOA) with the recombinant purified form of two polymorphic species of AGT, AGT-Ma and AGT-Mi, and with three pathogenic variants bearing previously identified folding defects: G41R-Ma, G170R-Mi, and I244T-Mi. We found that for all these enzyme AOA (i) forms an oxime at the active site, (ii) behaves as a slow, tight-binding inhibitor with KI values in the nanomolar range, and (iii) increases the thermal stability. Furthermore, experiments performed in mammalian cells revealed that AOA acts as a PC by partly preventing the intracellular aggregation of G41R-Ma and by promoting the correct peroxisomal import of G170R-Mi and I244T-Mi. Based on these data, we carried out a small-scale screening campaign. We identified four AOA analogues acting as AGT inhibitors, even if only one was found to act as a PC. The possible relationship between the structure and the PC activity of these compounds is discussed. Altogether, these results provide the proof-of-principle for the feasibility of a therapy with PCs for PH1-causing variants bearing folding defects and provide the scaffold for the identification of more specific ligands.
|
Authors | Elisa Oppici, Riccardo Montioli, Mirco Dindo, Laura Maccari, Valentina Porcari, Antonio Lorenzetto, Sara Chellini, Carla Borri Voltattorni, Barbara Cellini |
Journal | ACS chemical biology
(ACS Chem Biol)
Vol. 10
Issue 10
Pg. 2227-36
(Oct 16 2015)
ISSN: 1554-8937 [Electronic] United States |
PMID | 26161999
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
|
Chemical References |
- Molecular Chaperones
- Aminooxyacetic Acid
- Transaminases
- glyoxylate aminotransferase
- Alanine
|
Topics |
- Alanine
(genetics)
- Aminooxyacetic Acid
(chemistry, metabolism, pharmacology)
- Blotting, Western
- Fluorescent Antibody Technique
- Genetic Variation
- Humans
- Hyperoxaluria, Primary
(enzymology, genetics)
- Molecular Chaperones
(metabolism)
- Protein Folding
(drug effects)
- Protein Stability
- Transaminases
(genetics, metabolism)
|