RESUMEN
A new series of aryl-based synthetic mimics of antimicrobial peptides (SMAMPs) with antimicrobial activity and selectivity have been developed via systematic tuning of the aromatic groups and charge. The addition of a pendant aromatic group improved the antimicrobial activity against Gram-negative bacteria, while the addition of charge improved the selectivity. SMAMP 4 with six charges and a naphthalene central ring demonstrated a selectivity of 200 against both Staphylococcus aureus and Escherichia coli , compared with a selectivity of 8 for the peptide MSI-78. In addition to the direct antimicrobial activity, SMAMP 4 exhibited specific immunomodulatory activities in macrophages both in the presence and in the absence of lipopolysaccharide, a TLR agonist. SMAMP 4 also induced the production of a neutrophil chemoattractant, murine KC, in mouse primary cells. This is the first nonpeptidic SMAMP demonstrating both good antimicrobial and immunomodulatory activities.
Asunto(s)
Antiinfecciosos/química , Péptidos Catiónicos Antimicrobianos/química , Bacterias/efectos de los fármacos , Materiales Biomiméticos/química , Factores Inmunológicos/química , Animales , Antiinfecciosos/farmacología , Péptidos Catiónicos Antimicrobianos/farmacología , Materiales Biomiméticos/farmacología , Línea Celular , Escherichia coli/efectos de los fármacos , Infecciones por Escherichia coli/tratamiento farmacológico , Factores Inmunológicos/farmacología , Macrófagos/efectos de los fármacos , Ratones , Modelos Moleculares , Infecciones Estafilocócicas/tratamiento farmacológico , Staphylococcus aureus/efectos de los fármacosRESUMEN
Complement C1s protease inhibitors have potential utility in the treatment of diseases associated with activation of the classical complement pathway such as humorally mediated graft rejection, ischemia-reperfusion injury (IRI), vascular leak syndrome, and acute respiratory distress syndrome (ARDS). The utility of biphenylsulfonyl-thiophene-carboxamidine small-molecule C1s inhibitors are limited by their poor in vivo pharmacokinetic properties. Pegylation of a potent analog has provided compounds with good potency and good in vivo pharmacokinetic properties.
Asunto(s)
Amidas/química , Complemento C1s/antagonistas & inhibidores , Diseño de Fármacos , Polietilenglicoles/química , Inhibidores de Proteasas/síntesis química , Tiofenos/química , Animales , Complemento C1s/metabolismo , Semivida , Inhibidores de Proteasas/química , Inhibidores de Proteasas/farmacocinética , RatasRESUMEN
We have developed a novel series of potent and selective factor Xa inhibitors that employ a key 7-fluoroindazolyl moiety. The 7-fluoro group on the indazole scaffold replaces the carbonyl group of an amide that is found in previously reported factor Xa inhibitors. The structure of a factor Xa cocrystal containing 7-fluoroindazole 51a showed the 7-fluoro atom hydrogen-bonding with the N-H of Gly216 (2.9 A) in the peptide backbone. Thus, the 7-fluoroindazolyl moiety not only occupied the same space as the carbonyl group of an amide found in prior factor Xa inhibitors but also maintained a hydrogen bond interaction with the protein's beta-sheet domain. The structure-activity relationship for this series was consistent with this finding, as the factor Xa inhibitory potencies were about 60-fold greater (DeltaDelta G approximately 2.4 kcal/mol) for the 7-fluoroindazoles 25a and 25c versus the corresponding indazoles 25b and 25d. Highly convergent synthesis of these factor Xa inhibitors is also described.
Asunto(s)
Inhibidores del Factor Xa , Indazoles/síntesis química , Inhibidores de Serina Proteinasa/síntesis química , Células CACO-2 , Permeabilidad de la Membrana Celular , Cristalografía por Rayos X , Factor Xa/química , Humanos , Enlace de Hidrógeno , Técnicas In Vitro , Indazoles/química , Indazoles/farmacología , Microsomas Hepáticos/enzimología , Modelos Moleculares , Conformación Proteica , Inhibidores de Serina Proteinasa/química , Inhibidores de Serina Proteinasa/farmacología , Relación Estructura-Actividad , TermodinámicaRESUMEN
Complement activation has been implicated in disease states such as hereditary angioedema, ischemia-reperfusion injury, acute respiratory distress syndrome, and acute transplant rejection. Even though the complement cascade provides several protein targets for potential therapeutic intervention only two complement inhibitors have been approved so far for clinical use including anti-C5 antibodies for the treatment of paroxysmal nocturnal hemoglobinuria and purified C1-esterase inhibitor replacement therapy for the control of hereditary angioedema flares. In the present study, optimization of potency and physicochemical properties of a series of thiophene amidine-based C1s inhibitors with potential utility as intravenous agents for the inhibition of the classical pathway of complement is described.
Asunto(s)
Complemento C1s/antagonistas & inhibidores , Compuestos Heterocíclicos/química , Compuestos Heterocíclicos/farmacología , Animales , Sitios de Unión , Semivida , Modelos Moleculares , Estructura Molecular , Ratas , Relación Estructura-ActividadRESUMEN
The binding of lead compounds and drugs to human serum albumin (HSA) is a ubiquitous problem in drug discovery since it modulates the availability of the leads and drugs to their intended target, which is linked to biological efficacy. In our continuing efforts to identify small molecule alpha(V)beta(3) and alpha(V)beta(5) dual antagonists, we recently reported indoles 2-4 as potent and selective alpha(V)beta(3)/alpha(V)beta(5) antagonists with good oral bioavailability profile. In spite of subnanomolar binding affinity of these compounds to human alpha(V)beta(3) and alpha(V)beta(5) integrins, high HSA binding (96.5-97.3%) emerged as a limiting feature for these leads. Structure-activity HSA binding data of organic acids reported in the literature have demonstrated that the incorporation of polar groups into a given molecule can dramatically decrease the affinity toward HSA. We sought to apply this strategy by examining the effects of such modifications in both the central core constrain and the substituent beta to the carboxylate. Most of these derivatives were prepared in good yields through a cesium fluoride-catalyzed coupling reaction. This reaction was successful with a variety of nitrogen-containing scaffolds (20, 33, and 43) and selected acetylenic derivatives (16, 19, and 34). Among the compounds synthesized, the 3-[5-[2-(5,6,7,8-tetrahydro [1,8]naphthyridin-2-yl)ethoxy]indol-1-yl]-3-[5-(N,N-dimethylaminomethyl)-3-pyridyl]propionic acid (25) was found to be the most promising derivative within this novel series with a subnanomolar affinity for both alpha(v)beta(3) and alpha(v)beta(5) (IC(50) = 0.29 and 0.16 nM, respectively), similar to our initial lead receptor antagonists 2-4, and exhibiting a low HSA protein binding (40% bound, K(d) = 1.1+/-0.4 x 10(3) microM) and an improved in vitro stability profile toward human and mouse microsomes (99.9% and 98.7% remaining after 10 min). Moreover, the selectivity of 25 toward alpha(5)beta(1) and IIbIIIa integrins was perfectly maintained when compared to the parent leads 2-4. Thus, compound 25 was selected as a new lead with improved drug-like properties for further evaluations in the field of oncology and osteoporosis.
Asunto(s)
Integrina alfaVbeta3/antagonistas & inhibidores , Integrinas/antagonistas & inhibidores , Receptores de Vitronectina/antagonistas & inhibidores , Albúmina Sérica/metabolismo , Alquinos/síntesis química , Alquinos/química , Bencimidazoles/química , Esterificación , Humanos , Hipoxantinas/síntesis química , Hipoxantinas/química , Indoles/síntesis química , Indoles/química , Estructura Molecular , Propionatos/síntesis química , Propionatos/química , Unión Proteica , Relación Estructura-ActividadRESUMEN
Development of alphavbeta3-integrin inhibitors has been hampered by a lack of pharmacodynamic endpoints to identify doses that inhibit alphavbeta3 in vivo. To address this need, we developed an alphavbeta3 radioreceptor assay (RRA) that could be performed in 100% plasma. The RRA was based on 125I-echistatin binding to plate-immobilized alphavbeta3. Small molecule alphavbeta3 inhibitors efficiently competed echistatin binding to alphavbeta3 when the assay was carried out in buffer. However, when carried out in 100% plasma, the RRA revealed a 45 to >3000-fold loss in compound potencies. The losses in potency reflected, in part, the high plasma protein binding by the compounds examined. The RRA was adapted as an ex vivo pharmacodynamic model. Echistatin binding was measured in the presence of plasma harvested at timed intervals from rats dosed with select compounds. Using this pharmacodynamic model, compound and dose selection was optimized for further testing in models of corneal angiogenesis. Moderate anti-angiogenic activity was achieved when rats were dosed sufficient to achieve sustained (>50%) plasma inhibition through the trough interval. Thus, the RRA provided a simple technique to rank order compound potency in plasma, and could find general use as an ex vivo pharmacodynamic assay to select compounds and doses for preclinical and clinical proof-of-principle studies.
Asunto(s)
Integrina alfaVbeta3/antagonistas & inhibidores , Integrina alfaVbeta3/sangre , Ensayo de Unión Radioligante/métodos , Inhibidores de la Angiogénesis/farmacocinética , Inhibidores de la Angiogénesis/farmacología , Animales , Plaquetas/efectos de los fármacos , Plaquetas/metabolismo , Proteínas Sanguíneas/metabolismo , Córnea/irrigación sanguínea , Córnea/efectos de los fármacos , Evaluación Preclínica de Medicamentos , Técnicas In Vitro , Péptidos y Proteínas de Señalización Intercelular , Masculino , Neovascularización Patológica/prevención & control , Péptidos/sangre , Péptidos/farmacocinética , Unión Proteica , Ratas , Ratas Sprague-DawleyRESUMEN
Plasmodium falciparum pathogenesis is affected by various cell types in the blood, including platelets, which can kill intraerythrocytic malaria parasites. Platelets could mediate these antimalarial effects through human defense peptides (HDPs), which exert antimicrobial effects by permeabilizing membranes. Therefore, we screened a panel of HDPs and determined that human platelet factor 4 (hPF4) kills malaria parasites inside erythrocytes by selectively lysing the parasite digestive vacuole (DV). PF4 rapidly accumulates only within infected erythrocytes and is required for parasite killing in infected erythrocyte-platelet cocultures. To exploit this antimalarial mechanism, we tested a library of small, nonpeptidic mimics of HDPs (smHDPs) and identified compounds that kill P. falciparum by rapidly lysing the parasite DV while sparing the erythrocyte plasma membrane. Lead smHDPs also reduced parasitemia in a murine malaria model. Thus, identifying host molecules that control parasite growth can further the development of related molecules with therapeutic potential.
Asunto(s)
Antimaláricos/aislamiento & purificación , Antimaláricos/metabolismo , Plasmodium falciparum/efectos de los fármacos , Factor Plaquetario 4/metabolismo , Animales , Supervivencia Celular/efectos de los fármacos , Modelos Animales de Enfermedad , Eritrocitos/parasitología , Malaria/tratamiento farmacológico , Malaria/parasitología , Ratones , Carga de Parásitos , Parasitemia/tratamiento farmacológico , Parasitemia/parasitologíaRESUMEN
2-(2-Chloro-6-fluorophenyl)acetamides having 2,2-difluoro-2-aryl/heteroaryl-ethylamine P3 and oxyguanidine P1 substituents are potent thrombin inhibitors (K(i)=0.9-33.9 nM). 2-(5-Chloro-pyridin-2-yl)-2,2-difluoroethylamine was the best P3 substituent, yielding the most potent inhibitor (K(i)=0.7 nM). Replacing the P3 heteroaryl group with a phenyl ring or replacing the difluoro substitution with dimethyl or cyclopropyl groups in the linker reduced the affinity for thrombin significantly. The aminopyridine P1s also provided an increase in potency.
Asunto(s)
Acetamidas/síntesis química , Acetamidas/farmacología , Anticoagulantes/síntesis química , Anticoagulantes/farmacología , Hidrocarburos Halogenados/síntesis química , Hidrocarburos Halogenados/farmacología , Trombina/antagonistas & inhibidores , Acetamidas/química , Anticoagulantes/química , Cristalografía por Rayos X , Evaluación Preclínica de Medicamentos , Humanos , Hidrocarburos Halogenados/química , Estructura Molecular , Relación Estructura-Actividad , Trombina/químicaRESUMEN
We describe the synthesis and structure/activity relationship of RGD mimetics that are potent inhibitors of the integrin alpha(v)beta3. Indol-1-yl propionic acids containing a variety of basic moieties at the 5-position, as well as substitutions alpha and beta to the carboxy terminus were synthesized and evaluated. Novel compounds with improved potency have been identified.