Littérature scientifique sur le sujet « Sar/spr »

Focal Inhibitory Interneuron Loss and Principal Cell Hyperexcitability in the Rat Hippocampus After Microinjection of a Neurotoxic Conjugate of Saporin and a Peptidase-Resistant Analog of Substance P Martin JL, Sloviter RS J Comp Neurol 2001;436:127–152 Episodes of prolonged seizures or head trauma produce chronic hippocampal network hyperexcitability hypothesized to result primarily from inhibitory interneuron loss or dysfunction. The possibly causal role of inhibitory neuron failure in the development of epileptiform pathophysiology remains unclear because global neurologic injuries produce such a multitude of effects. The recent finding that Substance P receptors (SPRs) are expressed exclusively in the rat hippocampus by inhibitory interneurons provided the rationale for attempting to ablate interneurons selectively by using neurotoxic conjugates of SPR ligands and the ribosome inactivating protein saporin that specifically target Substance P receptor-expressing cells. Whereas intrahippocampal microinjection of a conjugate of native SP and saporin produced significant nonspecific damage at concentrations needed to produce even limited selective loss of SPR-positive cells, a conjugate of saporin and the more potent and peptidase-resistant SP analog [Sar(9), Met(O(2))(11)] Substance P (SSP-saporin) caused negligible nonspecific damage at the injection site, and a virtually complete loss of SPR-like immunoreactivity (LI) up to 1 mm from the injection site. Within the SPR depletion zone, immunoreactivities for most GABA-, parvalbumin-, so-matostatin-, and cholecystokinin-immunoreactive cells and fibers were eliminated. The few interneurons detectable within the affected zone were devoid of SPR-LI. The apparent loss of interneurons was selective in that calbindin- and glutamate receptor subunit 2 (GluR2)-positive principal cells survived within the affected zone, as did myelinated fibers and the extrinsic calretinin- and tyrosine hydroxylase—immunoreactive terminals of subcortical afferents. An apparent lack of reactive synaptic reorganization in response to interneuron loss was indicated by zinc transporter-3 (ZnT3)—and beta-synu-clein—LI, as well as by Timm staining, all of which revealed relatively normal patterns of excitatory terminal distribution. Control injections produced minor damage at the injection site, but no apparent specific loss of SPR-LI. One to 12 weeks after injection of SSP-saporin, extracellular electrophysiological field responses recorded in the CA1 pyramidal and dentate granule cell layers in response to afferent stimulation were blindly evaluated simultaneously in two sites 1–2 mm apart along the longitudinal hippocampal axis. SSP-saporin-treated rats exhibited relatively normal responses in some sites, whereas disinhibition and hyperexcitability indistinguishable from the pathophysiology produced by experimental status epilepticus were simultaneously recorded at adjacent sites. Anatomic analysis of the recording sites in each animal revealed that epileptiform pathophysiology was consistently observed only within areas of SPR ablation, whereas relatively normal evoked responses were recorded from immediately adjacent and relatively unaffected regions. These data establish the efficacy of [Sar(9), Met(O(2))(11)] Substance P-saporin for producing a selective and spatially extensive ablation of hippocampal inhibitory interneurons in vivo and a highly focal disinhibition that was restricted to the site of interneuron loss. These results also demonstrate that the “epileptic” pathophysiology produced by experimental status epilepticus or head trauma can be replicated by focal interneuron loss per se, without involving principal cell loss and other interpretive confounds inherent in the use of global neurologic injury models.

Drug-resistant Staphylococcus aureus is an imminent threat to public health, increasing the importance of drug discovery utilizing unexplored bacterial pathways and enzyme targets. De novo pyrimidine biosynthesis is a specialized, highly conserved pathway implicated in both the survival and virulence of several clinically relevant pathogens. Class I dihydroorotase (DHOase) is a separate and distinct enzyme present in gram positive bacteria (i.e., S. aureus, B. anthracis) that converts carbamoyl-aspartate (Ca-asp) to dihydroorotate (DHO)—an integral step in the de novo pyrimidine biosynthesis pathway. This study sets forth a high-throughput screening (HTS) of 3000 fragment compounds by a colorimetry-based enzymatic assay as a primary screen, identifying small molecule inhibitors of S. aureus DHOase (SaDHOase), followed by hit validation with a direct binding analysis using surface plasmon resonance (SPR). Competition SPR studies of six hit compounds and eight additional analogs with the substrate Ca-asp determined the best compound to be a competitive inhibitor with a KD value of 11 µM, which is 10-fold tighter than Ca-asp. Preliminary structure–activity relationship (SAR) provides the foundation for further structure-based antimicrobial inhibitor design against S. aureus.

The ability of AGP to bind circulating lipopolysaccharide (LPS) in plasma is believed to help reduce the proinflammatory effect of bacterial lipid A molecules. Here, for the first time we have characterized human AGP binding characteristics of the LPS from a number of pathogenic Gram-negative bacteria:Escherichia coli,Salmonella typhimurium,Klebsiella pneumonia,Pseudomonas aeruginosa, andSerratia marcescens. The binding affinity and structure activity relationships (SAR) of the AGP-LPS interactions were characterized by surface plasma resonance (SPR). In order to dissect the contribution of the lipid A, core oligosaccharide andO-antigen polysaccharide components of LPS, the AGP binding affinity of LPS from smooth strains, were compared to lipid A, Kdo2-lipid A,Ra,Rd, andRerough LPS mutants. The SAR analysis enabled by the binding data suggested that, in addition to the important role played by the lipid A and core components of LPS, it is predominately the unique species- and strain-specific carbohydrate structure of theO-antigen polysaccharide that largely determines the binding affinity for AGP. Together, these data are consistent with the role of AGP in the binding and transport of LPS in plasma during acute-phase inflammatory responses to invading Gram-negative bacteria.

Clofazimine and Arbidol have both been reported to be effective in vitro SARS-CoV-2 fusion inhibitors. Both are promising drugs that have been repurposed for the treatment of COVID-19 and have been used in several previous and ongoing clinical trials. Small-molecule bindings to expressed constructs of the trimeric S2 segment of Spike and the full-length SARS-CoV-2 Spike protein were measured using a Surface Plasmon Resonance (SPR) binding assay. We demonstrate that Clofazimine, Toremifene, Arbidol and its derivatives bind to the S2 segment of the Spike protein. Clofazimine provided the most reliable and highest-quality SPR data for binding with S2 over the conditions explored. A molecular docking approach was used to identify the most favorable binding sites on the S2 segment in the prefusion conformation, highlighting two possible small-molecule binding sites for fusion inhibitors. Results related to molecular docking and modeling of the structure–activity relationship (SAR) of a newly reported series of Clofazimine derivatives support the proposed Clofazimine binding site on the S2 segment. When the proposed Clofazimine binding site is superimposed with other experimentally determined coronavirus structures in structure–sequence alignments, the changes in sequence and structure may rationalize the broad-spectrum antiviral activity of Clofazimine in closely related coronaviruses such as SARS-CoV, MERS, hCoV-229E, and hCoV-OC43.

According to World Health Organization (WHO) cancer is one of top non- infectious death causes worldwide. In this context, as such the searching of new potent and safe anticancer drugs is a hot point for pharmacy industry and academic investigation. Despite protein kinases have been one of the most explored anticancer targets, its evolutionary degenerated parents, pseudokinases, have attracted the attention of scientific community during the last decade. Integrin Linked Kinase (ILK) is a member of the human pseudokinome that has been claimed and validated as a prommissing target for neoplastic diseases. The only well-known ILK inhibitor, CPD22, has probed its activity in phenotypic assays, however very few knowledge regarding its mechanism of action at molecular level is available. Using chemoinformatic and molecular modelling techniques we were able to elucidate if this molecule is able to bind to ILK and how. Additionally, our model explains the SAR raised from the optimization campaign, and SPR experiments have probed, by first time, that this molecule binds to ILK, thus supporting the hypothesis of inhibition by direct binding and the computational model as well.

Quantitative structure-activity/property relationships (QSAR/QSPR) approaches that have been applied with success in a number of studies are currently used as indispensable tools in the computational analysis of nanomaterials. Evolution of nano-QSAR methodology to the ranks of novel field of knowledge has resulted in the development of new so-called “nano-descriptors” and extension of the statistical approaches domain. This brief review focuses on the critical analysis of advantages and disadvantages of existing methods of nanoparticles' representation and their analysis in framework of structure-activity relationships. It summarizes recent QSAR/QSPR studies on inorganic nanomaterials. Here the authors describe practices for the QSAR modeling of inorganic nanoparticles, existing datasets, and discuss applicable descriptors and future perspectives of this field. About 50 different (Q)SAR/SPR models for inorganic nanomaterials have been developed during the past 5 years. An analysis of these peer reviewed publications shows that the most popular property of nanoparticles modeled via QSAR is their toxicity towards different bacteria, cell lines, and microorganisms. It has been clearly shown how nano-QSAR can contribute to the elucidation of toxicity mechanisms and different physical properties of inorganic nanomaterials.

For new chemical substances that are notified within the European Union, data sets have to be submitted to the National Competent Authorities. The data submitted have to demonstrate the physicochemical and toxic properties of the new chemical, such as solubility, partition coefficients and spectra, as well as acute toxic properties and the potential to cause local irritant or corrosive effects. In order to minimise testing for notification purposes (for example, animal testing), it is necessary to develop stepwise assessment procedures, including structure-activity considerations, alternative methods (for example, in vitro tests), and computerised structure-activity relationship (SAR) models. An electronic database was developed which contains physicochemical and toxicological data on approximately 1300 chemical substances. It is used for regulatory structure-property relationship (SPR) and SAR considerations, and for the development of rules for a decision support system (DSS) for the introduction of alternative methods into local irritancy/corrosivity testing strategies. The information stored in the database is derived from proprietary data, so it is not possible to publish the data directly. Therefore, the database is evaluated by regulators, and the information derived from the data is used for the development of scientific information about SARs. This information can be published, for example, by means of tables correlating measured physicochemical values and specific toxic effects caused by the measured chemical. This information is introduced to the public by means of a DSS that predicts local irritant/corrosive potential of a chemical by listing so-called exception rules of the kind IF (physicochemical property) A THEN not (toxic) Effect B and so-called structural rules of the kind IF Substructure A THEN Effect B. These DSS rules “translate” proprietary data into scientific knowledge that can be published.

Influenza is a highly contagious, acute respiratory illness, which represents one of the main health issues worldwide. Even though some antivirals are available, the alarming increase in virus strains resistant to them highlights the need to find new drugs. Previously, Superti et al. deeply investigated the mechanism of the anti-influenza virus effect of bovine lactoferrin (bLf) and the role of its tryptic fragments (the N- and C-lobes) in antiviral activity. Recently, through a truncation library, we identified the tetrapeptides, Ac-SKHS-NH2 (1) and Ac-SLDC-NH2 (2), derived from bLf C-lobe fragment 418–429, which were able to bind hemagglutinin (HA) and inhibit cell infection in a concentration range of femto- to picomolar. Starting from these results, in this work, we initiated a systematic SAR study on the peptides mentioned above, through an alanine scanning approach. We carried out binding affinity measurements by microscale thermophoresis (MST) and surface plasmon resonance (SPR), as well as hemagglutination inhibition (HI) and virus neutralization (NT) assays on synthesized peptides. Computational studies were performed to identify possible ligand–HA interactions. Results obtained led to the identification of an interesting peptide endowed with broad anti-influenza activity and able to inhibit viral infection to a greater extent of reference peptide.

Drug development is a very time, capital, and labor-intensive process. It was anticipated that bringing a novel chemical entity to market would take over a billion dollars and around 14 years [1]. In addition, drug development is characterized by a very high attrition rate both in preclinical and clinical studies. It was reported that only 40% of drug candidates with the most drug-like properties could make their way into clinical trials, and only 10% of these can eventually reach FDA approval [2]. After analyzing the data from seven UK‐based pharmaceutical companies from 1964 through 1985, Prentis et al. found that 39% of failure was attributed to poor pharmacokinetic (PK) profiles in humans, 29% was attributed to a lack of clinical efficacy, 21% was attributed to toxicity and adverse effects, and about 6% was attributed to commercial limitations [3]. When a drug candidate is identified with one of these issues (except the commercial limitations), normally, a new round of structureactivity or structure-property relationship (SAR/SPR) studies is carried out to generate a new chemical entity with improved profiles, and in most cases, such a process is time and labor-intensive. Alternatively, prodrug strategy can be leveraged to efficiently address associated drug developability issues without making enormous derivatives. Prodrug strategy has been demonstrated to be very successful and fruitful in drug development, with around 20% of approved drugs from 2008 through 2020 being clarified as prodrugs [4]. In recent years, prodrug strategy has also been leveraged to address the delivery issues associated with gasotransmitters, including NO, H2S, CO as well as SO2 [5-8]. In this thematic issue, six excellent reviews were included, focusing on varied prodrug strategies in addressing different drug developability issues associated with anticancer drugs, central nervous system (CNS) drugs, and gasotransmitters....

Although Malaria rates are on the decline due to the efforts of the World Health Organization and other organizations dedicated to the eradication of this disease, a relaxed attitude towards the development of new antimalarial entities would be flawed. Due to the emergence of resistance in the parasite, the almost 50% world-wide reduction in malarial death rates that have been produced over the past 15 years are threatening to be lost New drugs are urgently needed and our approach focuses on the re-evaluation and optimization of the historic antimalarial ICI 56,780. Due to its causal prophylactic activity, along with its ability to prevent transmission and potent blood schizonticidal activities, it was revisited with the hopes of first understanding which functionalities were responsible to the compound's activity. Secondly, we wanted to optimize the substituents in the 3, 6 and 7-positions. Finally and most importantly, we wanted to address the cross-resistance problem of the ICI 56,780 scaffold. Initial, analogues showed the importance of the ester in facilitating the convergence of the RI towards 1. Although those analogues lost activity in W2, TM90-C2B, and Pb, they were our first glimpse at this important trend that was later exploited in our 3-halo-6-butyl-7-(2-phenoxyethoxy)quinolin-4(1H)-one and 3-halo-6-butyl-2-methyl-7-(2-phenoxyethoxy)quinolin-4(1H)-ones which showed RI values of < 5 for our best analogues. Although our lead compound 3-bromo-6-butyl-2-methyl7-(2phenoxyethoxy)quinolin-4(1H) one possessed decreased activities as compared to ICI 56,780 at 2.60 nM for W2, 12.2 nM for TM90-C2B and 2.12 nM for Pb, it had 100% inhibition of parasite development on day 6 PE in our scouting assay and 61% inhibition on day 6in our Thompson model, increased from the < 2% value given by the ICI 56,780. Solubility and unfavorable in vivo stability were still major issues for this scaffold. Therefore, a series of piperazinyl 4(1H)-quinolones with greatly enhanced solubility were designed and tested in detailed structure activity relationships and structure property relationship studies. Initial results showed that 7-piperazinyl-4(1H)-quinolones possessed greatly increased solubilities when compared to ICI 56,780 analogues. Primarily, the linker length and the piperazine core was probed. This showed that compounds with a single carbon spacer were most active. Further testing of the 6-position gave methyl 6-methyl-4-oxo-7-((4-phenylpiperazin-1-yl)methyl)-1,4-dihydroquinoline-3-carboxylate with W2 and TM90-C2B values of 0.435 nM and 147 nM respectively. Substitution on the piperazinyl phenyl gave the most active compounds however the RI of >1500 was unacceptable. Because of this, 3-halo substituents were added to these quinolones with promising results. With RIs of < 3, the compounds were promising, however they were not active in vivo. However, methyl 6-methoxy-4-oxo-7-((4-(4-(trifluoromethyl)phenyl)piperazin-1-yl)methyl)-1,4-dihydroquinoline-3-carboxylate and methyl 6-methyl-4-oxo-7-((4-(4-(trifluoromethyl)phenyl)piperazin-1-yl)methyl)-1,4-dihydroquinoline-3-carboxylate both gave cures in our in vivo Thomson model. These studies highlight the potential in using detailed structural activity and structural property studies to re-evaluate and optimize historic antimalarials. These studies have introduced a new generation of soluble 4(1H)-quinolones with high potency against P. falciparum.

L'angiogenèse, ou processus de formation de nouveaux vaisseaux sanguins, joue un rôle majeur dans la progression de nombreux cancers et diverses pathologies oculaires. Les récepteurs aux chimiokines CXCR2 sont impliqués dans ces processus en médiant la prolifération cellulaire, l'inflammation et la formation de nouveaux vaisseaux sanguins. Le but de cette thèse a donc été de développer des antagonistes des récepteurs CXCR2 pour inhiber ces mécanismes pathologiques, et en particulier l'angiogenèse pathologique tumorale et oculaire. Sur la base de recherches antérieures, nous avons étudié de nouveaux analogues de N,N'-diarylurée comme inhibiteurs de la voie ELR+CXCL-CXCR2, pour le traitement du cancer. Deux séries d'analogues ont été synthétisées afin d'étudier la relation structure-activité et d'optimiser un composé lead. Des évaluations sur des lignées cellulaires de cancer du rein, de la tête et du cou et de mélanomes uvéaux, ainsi que sur des cultures sphéroïdes 3D ont identifié un composé lead optimisé, montrant une inhibition significative de l'invasion, de la migration et de la néo-angiogenèse. De plus, des études de pharmacologie, de pharmacodynamie et de polymorphisme ont été réalisées. Dans le cadre des pathologies oculaires angiogéniques, le développement d'une seconde famille de composés a été poursuivi, avec notamment l'étude de nouvelles voies de synthèse en vue d'une montée en échelle pour une future production industrielle et des études de formulation afin de réaliser des préparations de principes actifs sous forme de collyre. Enfin, une nouvelle série de composés à visée anticancéreuse a été conçue et une voie de synthèse a été développée pour obtenir une première série d'analogues. L'évaluation des activités biologiques de ces composés a permis de dégager une relation de structure-activité préliminaire
Angiogenesis, the process of forming new blood vessels, plays a crucial role in the progression of various cancers and ocular diseases. CXCR2 chemokine receptors are implicated in these processes by mediating cell proliferation, inflammation, and the formation of new blood vessels. This thesis aims to develop CXCR2 receptor antagonists to inhibit these pathological mechanisms, particularly pathological tumor and ocular angiogenesis. Based on previous research, we investigated new N,N'-diarylurea analogues as inhibitors of the ELR+CXCL-CXCR2 pathway for cancer treatment. Two series of analogues were synthesized to study the structure-activity relationship and to optimize a lead compound. Evaluations on renal, head and neck cancer, and uveal melanoma cell lines, as well as on 3D spheroid cultures, identified an optimized lead compound showing significant inhibition of invasion, migration, and neo-angiogenesis. Additionally, pharmacology, pharmacodynamics, and polymorphism studies were conducted.In the context of ocular angiogenic diseases, the development of a second family of compounds was pursued, including the study of new synthetic routes for scaling up for future industrial production and formulation studies to create active ingredient preparations in the form of eye drops.Finally, a new series of anticancer compounds was designed, and a synthetic route was developed to obtain a first series of analogues. The evaluation of the biological activities of these compounds allowed the establishment of a preliminary structure-activity relationship

Quantitative structure-activity/property relationships (QSAR/QSPR) approaches that have been applied with success in a number of studies are currently used as indispensable tools in the computational analysis of nanomaterials. Evolution of nano-QSAR methodology to the ranks of novel field of knowledge has resulted in the development of new so-called “nano-descriptors” and extension of the statistical approaches domain. This brief review focuses on the critical analysis of advantages and disadvantages of existing methods of nanoparticles' representation and their analysis in framework of structure-activity relationships. It summarizes recent QSAR/QSPR studies on inorganic nanomaterials. Here the authors describe practices for the QSAR modeling of inorganic nanoparticles, existing datasets, and discuss applicable descriptors and future perspectives of this field. About 50 different (Q)SAR/SPR models for inorganic nanomaterials have been developed during the past 5 years. An analysis of these peer reviewed publications shows that the most popular property of nanoparticles modeled via QSAR is their toxicity towards different bacteria, cell lines, and microorganisms. It has been clearly shown how nano-QSAR can contribute to the elucidation of toxicity mechanisms and different physical properties of inorganic nanomaterials.