| 11. |
- Diwakarla, Shanti, et al.
(författare)
-
Aryl Sulfonamide Inhibitors of Insulin-Regulated Aminopeptidase Enhance Spine Density in Primary Hippocampal Neuron Cultures
- 2016
-
Ingår i: ACS Chemical Neuroscience. - : American Chemical Society (ACS). - 1948-7193. ; 7:10, s. 1383-1392
-
Tidskriftsartikel (refereegranskat)abstract
- The zinc metallopeptidase insulin regulated aminopeptidase (IRAP), which is highly expressed in the hippocampus and other brain regions associated with cognitive function, has been identified as a high-affinity binding site of the hexapeptide angiotensin IV (Ang IV). This hexapeptide is thought to facilitate learning and memory by binding to the catalytic site of IRAP to inhibit its enzymatic activity. In support of this hypothesis, low molecular weight, nonpeptide specific inhibitors of TRAP have been shown to enhance memory in rodent models. Recently, it was demonstrated that linear and macrocyclic Ang IV-derived peptides can alter the shape and increase the number of dendritic spines in hippocampal cultures, properties associated with enhanced cognitive performance. After screening a library of 10 500 drug like substances for their ability to inhibit IRAP, we identified a series of low molecular weight aryl sulfonamides, which exhibit no structural similarity to Ang IV, as moderately potent IRAP inhibitors:A structural and biological characterization of three of these aryl sulfonamides was performed. Their binding modes to human IRAP were explored by docking calculations combined with molecular dynamics simulations and binding affinity estimations using the linear interaction energy method. Two alternative binding modes emerged from this analysis, both of which correctly rank the ligands according to their experimental binding affinities for this series of compounds. Finally, we show that two of these drug-like IRAP inhibitors can alter dendritic spine morphology and increase spine density in primary cultures of hippocampal neurons.
|
|
| 12. |
- Diwakarla, Shanti, et al.
(författare)
-
Binding to and Inhibition of Insulin-Regulated Aminopeptidase (IRAP) by Macrocyclic Disulfides Enhances Spine Density
- 2016
-
Ingår i: Molecular Pharmacology. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 0026-895X .- 1521-0111. ; 89:4, s. 413-424
-
Tidskriftsartikel (refereegranskat)abstract
- Angiotensin IV (Ang IV) and related peptide analogues, as well as non-peptide inhibitors of insulin-regulated aminopeptidase (IRAP), have previously been shown to enhance memory and cognition in animal models. Furthermore, the endogenous IRAP substrates oxytocin and vasopressin are known to facilitate learning and memory. In this study, the two recently synthesized 13-membered macrocylic competitive IRAP inhibitors HA08 and HA09, which were designed to mimic the N-terminal of oxytocin and vasopressin, were assessed and compared based on their ability to bind to the IRAP active site, and alter dendritic spine density in rat hippocampal primary cultures. The binding modes of the IRAP inhibitors HA08, HA09 and of Ang IV in either the extended or γ-turn conformation at the C-terminal to human IRAP were predicted by docking and molecular dynamics (MD) simulations. The binding free energies calculated with the linear interaction energy (LIE) method, which are in excellent agreement with experimental data and simulations, have been used to explain the differences in activities of the IRAP inhibitors, both of which are structurally very similar, but differ only with regard to one stereogenic center. In addition, we show that HA08, which is 100-fold more potent than the epimer HA09, can enhance dendritic spine number and alter morphology, a process associated with memory facilitation. Therefore, HA08, one of the most potent IRAP inhibitors known today, may serve as a suitable starting point for medicinal chemistry programs aided by MD simulations aimed at discovering more drug-like cognitive enhancers acting via augmenting synaptic plasticity.
|
|
| 13. |
- Engen, Karin, et al.
(författare)
-
Identification of Drug-Like Inhibitors of Insulin-Regulated Aminopeptidase Through Small-Molecule Screening
- 2016
-
Ingår i: Assay and drug development technologies. - : Mary Ann Liebert Inc. - 1540-658X .- 1557-8127. ; 14:3, s. 180-193
-
Tidskriftsartikel (refereegranskat)abstract
- Intracerebroventricular injection of angiotensin IV, a ligand of insulin-regulated aminopeptidase (IRAP), has been shown to improve cognitive functions in several animal models. Consequently, IRAP is considered a potential target for treatment of cognitive disorders. To identify nonpeptidic IRAP inhibitors, we adapted an established enzymatic assay based on membrane preparations from Chinese hamster ovary cells and a synthetic peptide-like substrate for high-throughput screening purposes. The 384-well microplate-based absorbance assay was used to screen a diverse set of 10,500 compounds for their inhibitory capacity of IRAP. The assay performance was robust with Z-values ranging from 0.81 to 0.91, and the screen resulted in 23 compounds that displayed greater than 60% inhibition at a compound concentration of 10M. After hit confirmation experiments, purity analysis, and promiscuity investigations, three structurally different compounds were considered particularly interesting as starting points for the development of small-molecule-based IRAP inhibitors. After resynthesis, all three compounds confirmed low M activity and were shown to be rapidly reversible. Additional characterization included activity in a fluorescence-based orthogonal assay and in the presence of a nonionic detergent and a reducing agent, respectively. Importantly, the characterized compounds also showed inhibition of the human ortholog, prompting our further interest in these novel IRAP inhibitors.
|
|
| 14. |
- Grönbladh, Alfhild, et al.
(författare)
-
[(35)S]GTPγS autoradiography for studies of opioid receptor functionality
- 2015
-
Ingår i: Methods in Molecular Biology. - New York, NY : Springer New York. - 1064-3745 .- 1940-6029. ; 1230, s. 169-176
-
Tidskriftsartikel (refereegranskat)abstract
- The opioid receptors have been an interesting target for the drug industry for decades. These receptors were pharmacologically characterized in the 1970s and several drugs and peptides have emerged over the years. In 2012, the crystal structures were also demonstrated, with new data on the receptor sites, and thus new possibilities will appear. The role of opioids in the brain has attracted considerable interest in several diseases, especially pain and drug dependence. The opioid receptors are G-protein-coupled receptors (GPCR) that are Gi-coupled which make them suitable for studying the receptor functionality. The [(35)S]GTPγS autoradiography assay is a good option that has the benefit of generating both anatomical and functional data in the area of interest. It is based on the first step of the signaling mechanism of GPCRs. When a ligand binds to the receptor GTP will replace GDP on the α-subunit of the G protein, leading to a dissociation of the βγ-subunit. These subunits will start a cascade of second messengers and subsequently a physiological response.
|
|
| 15. |
- Grönbladh, Alfhild, et al.
(författare)
-
The neurobiology and addiction potential of anabolic androgenic steroids and the effects of growth hormone
- 2016
-
Ingår i: Brain Research Bulletin. - : Elsevier BV. - 0361-9230 .- 1873-2747. ; 126, s. 127-137
-
Forskningsöversikt (refereegranskat)abstract
- Anabolic androgenic steroids (AAS) are substances that mimic the hormone testosterone, and primarily act via the androgen receptor. In addition to their physiological effect on muscle tissue and growth, research from the last decade has shown that AAS have a pronounced impact on the central nervous system. A large number of studies have demonstrated that AAS affect the mesolimbic reward system in the brain. However, whether the direct effects of AAS on endorphins, dopamine, serotonin and GABA etc. and on the corresponding and related systems lead to dependence needs to be further elucidated. According to recent studies, the prevalence of AAS dependence among AAS users has been estimated to be approximately 30%, and polysubstance use, of both pharmaceutical drugs and narcotics, within this group is common. The present review primarily discusses AAS in the context of addiction and dependence, and further addresses the issue of using multiple substances, i.e. stimulants and opiates in combination with AAS. In addition, aspects of the treatment of AAS dependence, the connection between AAS abuse and cognition, and AAS-induced neurotoxicity are presented. Currently, performance enhancing drugs are frequently used in combination with AAS. Therefore, a large section on growth hormone and insulin-like growth factor is also included.
|
|
| 16. |
|
|
| 17. |
- Hallberg, Mathias, 1971-, et al.
(författare)
-
From the Anti-Nociceptive Substance P Metabolite Substance P (1-7) to Small Peptidomimetics
- 2018
-
Ingår i: Current protein and peptide science. - : Bentham Science Publishers Ltd.. - 1389-2037 .- 1875-5550. ; 19:11, s. 1038-1048
-
Forskningsöversikt (refereegranskat)abstract
- Substance P (SP) is associated with pain and inflammatory processes and is released from terminals of specific sensory nerves. This undecapeptide that mediates its effects through the neurokinin type 1 (NK1) receptor, is rapidly degraded in vivo to smaller fragments. The heptapeptide SP(1-7) with a hitherto unknown receptor, is a major bioactive fragment and displays often opposite actions to those induced by SP. Hence, SP(1-7) elicits anti-nociceptive and anti-hyperalgesic effects. These observations have attracted a substantial interest and in this mini-review the efforts to transform the heptapeptide SP(1-7) into more drug-like small-molecule SP(1-7) peptidomimetics as a potential new class of analgesics are summarized. Structure-activity relationship studies and subsequent amidation of the C-terminal and truncations from the N-terminal of the heptapeptide delivered the bioactive dipeptide amide Gln-Phe-NH2 showing a high affinity at the SP(1-7) binding site. Similarly, endomorphin-2, an endogenous opioid ligand containing a C-terminal carboxamide group, demonstrated a high affinity at the SP(1-7) binding site. Endomorphin-2 subjected to truncations yielded the potent dipeptide amide Phe-Phe-NH2. Structural optimization of the latter furnished more drug-like high affinity ligands and among those a constrained cis-3-phenylpyrrolidine derivative that after peripheral administration produced a significant anti-allodynic effect in a mouse SNI model of neuropathic pain. This SP(1-7) peptidomimetic was as effective as SP(1-7) in alleviating mechanical allodynia in mice. Although, additional structural modifications are needed to achieve compounds exhibiting high/fair bioavailability after oral administration, the examples presented herein demonstrate that the bioactive peptides SP(1-7) and endomorphin-2 can be converted into low molecular weight compounds that are able to mimic the in vivo actions of the heptapeptide SP(1-7).
|
|
| 18. |
- Hallberg, Mathias
(författare)
-
Neuropeptides : Metabolism to Bioactive Fragments and the Pharmacology of Their Receptors
- 2015
-
Ingår i: Medicinal research reviews (Print). - : Wiley. - 0198-6325 .- 1098-1128. ; 35:3, s. 464-519
-
Forskningsöversikt (refereegranskat)abstract
- The proteolytic processing of neuropeptides has an important regulatory function and the peptide fragments resulting from the enzymatic degradation often exert essential physiological roles. The proteolytic processing generates, not only biologically inactive fragments, but also bioactive fragments that modulate or even counteract the response of their parent peptides. Frequently, these peptide fragments interact with receptors that are not recognized by the parent peptides. This review discusses tachykinins, opioid peptides, angiotensins, bradykinins, and neuropeptide Y that are present in the central nervous system and their processing to bioactive degradation products. These well-known neuropeptide systems have been selected since they provide illustrative examples that proteolytic degradation of parent peptides can lead to bioactive metabolites with different biological activities as compared to their parent peptides. For example, substance P, dynorphin A, angiotensin I and II, bradykinin, and neuropeptide Y are all degraded to bioactive fragments with pharmacological profiles that differ considerably from those of the parent peptides. The review discusses a selection of the large number of drug-like molecules that act as agonists or antagonists at receptors of neuropeptides. It focuses in particular on the efforts to identify selective drug-like agonists and antagonists mimicking the effects of the endogenous peptide fragments formed. As exemplified in this review, many common neuropeptides are degraded to a variety of smaller fragments but many of the fragments generated have not yet been examined in detail with regard to their potential biological activities. Since these bioactive fragments contain a small number of amino acid residues, they provide an ideal starting point for the development of drug-like substances with ability to mimic the effects of the degradation products. Thus, these substances could provide a rich source of new pharmaceuticals. However, as discussed herein relatively few examples have so far been disclosed of successful attempts to create bioavailable, drug-like agonists or antagonists, starting from the structure of endogenous peptide fragments and applying procedures relying on stepwise manipulations and simplifications of the peptide structures.
|
|
| 19. |
- Isaksson, Rebecka, et al.
(författare)
-
A Series of Analogues to the AT2R Prototype Antagonist C38 Allow Fine Tuning of the Previously Reported Antagonist Binding Mode
- 2019
-
Ingår i: ChemistryOpen. - : Wiley. - 2191-1363. ; 8:1, s. 114-125
-
Tidskriftsartikel (refereegranskat)abstract
- We here report on our continued studies of ligands binding tothe promising drug target angiotensin II type 2 receptor (AT2R). Two series of compounds were synthesized and investigated. The first series explored the effects of adding small substituents to the phenyl ring of the known selective nonpeptide AT2R antagonist C38, generating small but significant shifts in AT2R affinity. One compound in the first series was equipotent to C38 and showed similar kinetic solubility, and stability in both human and mouse liver microsomes. The second series was comprised of new bicyclic derivatives, amongst which one ligand exhibited a five-fold improved affinity to AT2R ascompared to C38. The majority of the compounds in the second series, including the most potent ligand, were inferior to C38 with regard to stability in both human and mouse microsomes. In contrast to our previously reported findings, ligands with shorter carbamate alkyl chains only demonstrated slightly improved stability in microsomes. Based on data presented herein, a more adequate, tentative model of the binding modes of ligand analogues to the prototype AT2R antagonist C38 is proposed, as deduced from docking redefined by molecular dynamic simulations.
|
|
| 20. |
|
|
