Nejvíce citovaný článek - PubMed ID 27208881
Comparison of human glutamate carboxypeptidases II and III reveals their divergent substrate specificities
Glutamate carboxypeptidase II (GCPII, also known as PSMA or FOLH1) is responsible for the cleavage of N-acetyl-aspartyl-glutamate (NAAG) to N-acetyl-aspartate and glutamate in the central nervous system and facilitates the intestinal absorption of folate by processing dietary folyl-poly-γ-glutamate in the small intestine. The physiological function of GCPII in other organs like kidneys is still not known. GCPII inhibitors are neuroprotective in various conditions (e.g., ischemic brain injury) in vivo; however, their utilization as potential drug candidates has not been investigated in regard to not yet known GCPII activities. To explore the GCPII role and possible side effects of GCPII inhibitors, we performed parallel metabolomic and lipidomic analysis of the cerebrospinal fluid (CSF), urine, plasma, and brain tissue of mice with varying degrees of GCPII deficiency (fully deficient in Folh1, -/-; one allele deficient in Folh1, +/-; and wild type, +/+). Multivariate analysis of metabolites showed no significant differences between wild-type and GCPII-deficient mice (except for NAAG), although changes were observed between the sex and age. NAAG levels were statistically significantly increased in the CSF, urine, and plasma of GCPII-deficient mice. However, no difference in NAAG concentrations was found in the whole brain lysate likely because GCPII, as an extracellular enzyme, can affect only extracellular and not intracellular NAAG concentrations. Regarding the lipidome, the most pronounced genotype-linked changes were found in the brain tissue. In brains of GCPII-deficient mice, we observed statistically significant enrichment in phosphatidylcholine-based lipids and reduction of sphingolipids and phosphatidylethanolamine plasmalogens. We hypothesize that the alteration of the NAA-NAAG axis by absent GCPII activity affected myelin composition. In summary, the absence of GCPII and thus similarly its inhibition do not have detrimental effects on metabolism, with just minor changes in the brain lipidome.
- Klíčová slova
- FOLH1, N-acetyl-aspartyl-glutamate, folyl-poly-γ-glutamyl hydrolase I, glutamate carboxypeptidase II, lipidomics, metabolomics,
- MeSH
- dipeptidy metabolismus MeSH
- glutamátkarboxypeptidasa II * genetika metabolismus MeSH
- kyselina glutamová MeSH
- lipidomika * MeSH
- lipidy chemie MeSH
- metabolomika * MeSH
- mozek metabolismus MeSH
- myši MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- dipeptidy MeSH
- Folh1 protein, mouse MeSH Prohlížeč
- glutamátkarboxypeptidasa II * MeSH
- isospaglumic acid MeSH Prohlížeč
- kyselina glutamová MeSH
- lipidy MeSH
Human glutamate carboxypeptidase 2 (GCP2) from the M28B metalloprotease group is an important target for therapy in neurological disorders and an established tumor marker. However, its physiological functions remain unclear. To better understand general roles, we used the model organism Caenorhabditis elegans to genetically manipulate its three existing orthologous genes and evaluate the impact on worm physiology. The results of gene knockout studies showed that C. elegans GCP2 orthologs affect the pharyngeal physiology, reproduction, and structural integrity of the organism. Promoter-driven GFP expression revealed distinct localization for each of the three gene paralogs, with gcp-2.1 being most abundant in muscles, intestine, and pharyngeal interneurons, gcp-2.2 restricted to the phasmid neurons, and gcp-2.3 located in the excretory cell. The present study provides new insight into the unique phenotypic effects of GCP2 gene knockouts in C. elegans, and the specific tissue localizations. We believe that elucidation of particular roles in a non-mammalian organism can help to explain important questions linked to physiology of this protease group and in extension to human GCP2 involvement in pathophysiological processes.
- Klíčová slova
- N-acetyl-aspartyl-glutamate, folate hydrolase 1, phenotyping, promoter-driven GFP expression, prostate-specific membrane antigen,
- MeSH
- Caenorhabditis elegans * genetika MeSH
- karboxypeptidasy genetika metabolismus MeSH
- lidé MeSH
- promotorové oblasti (genetika) MeSH
- proteiny Caenorhabditis elegans * genetika metabolismus MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- glutamate carboxypeptidase MeSH Prohlížeč
- karboxypeptidasy MeSH
- proteiny Caenorhabditis elegans * MeSH
Prostate-specific membrane antigen (PSMA) is a well-characterized tumor marker associated with prostate cancer and neovasculature of most solid tumors. PSMA-specific ligands are thus being developed to deliver imaging or therapeutic agents to cancer cells. Here, we report on a crystal structure of human PSMA in complex with A9g, a 43-bp PSMA-specific RNA aptamer, that was determined to the 2.2 Å resolution limit. The analysis of the PSMA/aptamer interface allows for identification of key interactions critical for nanomolar binding affinity and high selectivity of A9g for human PSMA. Combined with in silico modeling, site-directed mutagenesis, inhibition experiments and cell-based assays, the structure also provides an insight into structural changes of the aptamer and PSMA upon complex formation, mechanistic explanation for inhibition of the PSMA enzymatic activity by A9g as well as its ligand-selective competition with small molecules targeting the internal pocket of the enzyme. Additionally, comparison with published protein-RNA aptamer structures pointed toward more general features governing protein-aptamer interactions. Finally, our findings can be exploited for the structure-assisted design of future A9g-based derivatives with improved binding and stability characteristics.
- MeSH
- antigeny povrchové chemie MeSH
- aptamery nukleotidové chemie MeSH
- buňky PC-3 MeSH
- glutamátkarboxypeptidasa II chemie MeSH
- HEK293 buňky MeSH
- interakční proteinové domény a motivy MeSH
- lidé MeSH
- ligandy MeSH
- molekulární struktura MeSH
- nádorové biomarkery chemie MeSH
- nádory prostaty metabolismus MeSH
- vazba proteinů MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
- Názvy látek
- A9g RNA aptamer MeSH Prohlížeč
- antigeny povrchové MeSH
- aptamery nukleotidové MeSH
- FOLH1 protein, human MeSH Prohlížeč
- glutamátkarboxypeptidasa II MeSH
- ligandy MeSH
- nádorové biomarkery MeSH
A series of carbamate-based inhibitors of glutamate carboxypeptidase II (GCPII) were designed and synthesized using ZJ-43, N-[[[(1S)-1-carboxy-3-methylbutyl]amino]carbonyl]-l-glutamic acid, as a molecular template in order to better understand the impact of replacing one of the two nitrogen atoms in the urea-based GCPII inhibitor with an oxygen atom. Compound 7 containing a C-terminal 2-oxypentanedioic acid was more potent than compound 5 containing a C-terminal glutamic acid (2-aminopentanedioic acid) despite GCPII's preference for peptides containing an N-terminal glutamate as substrates. Subsequent crystallographic analysis revealed that ZJ-43 and its two carbamate analogs 5 and 7 with the same (S,S)-stereochemical configuration adopt a nearly identical binding mode while (R,S)-carbamate analog 8 containing a d-leucine forms a less extensive hydrogen bonding network. QM and QM/MM calculations have identified no specific interactions in the GCPII active site that would distinguish ZJ-43 from compounds 5 and 7 and attributed the higher potency of ZJ-43 and compound 7 to the free energy changes associated with the transfer of the ligand from bulk solvent to the protein active site as a result of the lower ligand strain energy and solvation/desolvation energy. Our findings underscore a broader range of factors that need to be taken into account in predicting ligand-protein binding affinity. These insights should be of particular importance in future efforts to design and develop GCPII inhibitors for optimal inhibitory potency.
- Klíčová slova
- Crystal structure, Glutamate carboxypeptidase II, Metallopeptidase, Prostate-specific membrane antigen,
- MeSH
- buněčné linie MeSH
- Drosophila genetika MeSH
- enzymatické testy MeSH
- glutamátkarboxypeptidasa II antagonisté a inhibitory chemie metabolismus MeSH
- inhibitory proteas chemická syntéza chemie metabolismus MeSH
- karbamáty chemická syntéza chemie metabolismus MeSH
- katalytická doména MeSH
- kvantová teorie MeSH
- lidé MeSH
- močovina analogy a deriváty chemická syntéza chemie metabolismus MeSH
- molekulární modely MeSH
- stereoizomerie MeSH
- vazba proteinů MeSH
- vodíková vazba MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
- Názvy látek
- glutamátkarboxypeptidasa II MeSH
- inhibitory proteas MeSH
- karbamáty MeSH
- močovina MeSH
- ZJ43 MeSH Prohlížeč
Glutamate carboxypeptidase II (GCPII), also known as prostate-specific membrane antigen (PSMA) or folate hydrolase, is a metallopeptidase expressed predominantly in the human brain and prostate. GCPII expression is considerably increased in prostate carcinoma, and the enzyme also participates in glutamate excitotoxicity in the brain. Therefore, GCPII represents an important diagnostic marker of prostate cancer progression and a putative target for the treatment of both prostate cancer and neuronal disorders associated with glutamate excitotoxicity. For the development of novel therapeutics, mouse models are widely used. However, although mouse GCPII activity has been characterized, a detailed comparison of the enzymatic activity and tissue distribution of the mouse and human GCPII orthologs remains lacking. In this study, we prepared extracellular mouse GCPII and compared it with human GCPII. We found that mouse GCPII possesses lower catalytic efficiency but similar substrate specificity compared with the human protein. Using a panel of GCPII inhibitors, we discovered that inhibition constants are generally similar for mouse and human GCPII. Furthermore, we observed highest expression of GCPII protein in the mouse kidney, brain, and salivary glands. Importantly, we did not detect GCPII in the mouse prostate. Our data suggest that the differences in enzymatic activity and inhibition profile are rather small; therefore, mouse GCPII can approximate human GCPII in drug development and testing. On the other hand, significant differences in GCPII tissue expression must be taken into account when developing novel GCPII-based anticancer and therapeutic methods, including targeted anticancer drug delivery systems, and when using mice as a model organism.
- Klíčová slova
- glutamate carboxypeptidase II, mouse animal model, neuronal disorders, prostate cancer, prostate‐specific membrane antigen,
- Publikační typ
- časopisecké články MeSH