RESUMO
Although most acute skin wounds heal rapidly, non-healing skin ulcers represent an increasing and substantial unmet medical need that urgently requires effective therapeutics. Keratinocytes resurface wounds to re-establish the epidermal barrier by transitioning to an activated, migratory state, but this ability is lost in dysfunctional chronic wounds. Small-molecule regulators of keratinocyte plasticity with the potential to reverse keratinocyte malfunction in situ could offer a novel therapeutic approach in skin wound healing. Utilizing high-throughput phenotypic screening of primary keratinocytes, we identify such small molecules, including bromodomain and extra-terminal domain (BET) protein family inhibitors (BETi). BETi induce a sustained activated, migratory state in keratinocytes in vitro, increase activation markers in human epidermis ex vivo and enhance skin wound healing in vivo. Our findings suggest potential clinical utility of BETi in promoting keratinocyte re-epithelialization of skin wounds. Importantly, this novel property of BETi is exclusively observed after transient low-dose exposure, revealing new potential for this compound class.
Assuntos
Proteínas de Ciclo Celular/genética , Epiderme/efeitos dos fármacos , Reepitelização/efeitos dos fármacos , Úlcera Cutânea/tratamento farmacológico , Bibliotecas de Moléculas Pequenas/farmacologia , Fatores de Transcrição/genética , Ferimentos não Penetrantes/tratamento farmacológico , Animais , Proteínas de Ciclo Celular/antagonistas & inibidores , Proteínas de Ciclo Celular/metabolismo , Modelos Animais de Doenças , Epiderme/metabolismo , Epiderme/patologia , Transferência Ressonante de Energia de Fluorescência , Regulação da Expressão Gênica , Ensaios de Triagem em Larga Escala , Humanos , Queratinócitos/efeitos dos fármacos , Queratinócitos/metabolismo , Queratinócitos/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Cultura Primária de Células , Isoformas de Proteínas/antagonistas & inibidores , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Precursores de Proteínas/antagonistas & inibidores , Precursores de Proteínas/genética , Precursores de Proteínas/metabolismo , Reepitelização/genética , Úlcera Cutânea/genética , Úlcera Cutânea/metabolismo , Úlcera Cutânea/patologia , Bibliotecas de Moléculas Pequenas/química , Relação Estrutura-Atividade , Fatores de Transcrição/antagonistas & inibidores , Fatores de Transcrição/metabolismo , Transcrição Gênica , Ferimentos não Penetrantes/genética , Ferimentos não Penetrantes/metabolismo , Ferimentos não Penetrantes/patologiaRESUMO
Myeloperoxidase (MPO) is a leukocyte-derived redox enzyme that has been linked to oxidative stress and damage in many inflammatory states, including cardiovascular disease. We have discovered aminopyridines that are potent mechanism-based inhibitors of MPO, with significant selectivity over the closely related thyroid peroxidase. 1-((6-Aminopyridin-3-yl)methyl)-3-(4-bromophenyl)urea (Aminopyridine 2) inhibited MPO in human plasma and blocked MPO-dependent vasomotor dysfunction ex vivo in rat aortic rings. Aminopyridine 2 also showed high oral bioavailability and inhibited MPO activity in vivo in a mouse model of peritonitis. Aminopyridine 2 could effectively be administered as a food admixture, making it an important tool for assessing the relative importance of MPO in preclinical models of chronic inflammatory disease.
Assuntos
Aminopiridinas/farmacologia , Inibidores Enzimáticos/farmacologia , Peroxidase/antagonistas & inibidores , Animais , Aorta/efeitos dos fármacos , Aorta/metabolismo , Disponibilidade Biológica , Humanos , Inflamação/tratamento farmacológico , Inflamação/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Ratos , Ratos Sprague-DawleyRESUMO
Small interfering RNA (siRNA) is a novel therapeutic modality that benefits from nanoparticle mediated delivery. The most clinically advanced siRNA-containing nanoparticles are polymer-coated supramolecular assemblies of siRNA and lipids (lipid nanoparticles or LNPs), which protect the siRNA from nucleases, modulate pharmacokinetics of the siRNA, and enable selective delivery of siRNA to target cells. Understanding the mechanisms of assembly and delivery of such systems is complicated by the complexity of the dynamic supramolecular assembly as well as by its subsequent interactions with the biological milieu. We have developed an ex vivo method that provides insight into how LNPs behave when contacted with biological fluids. Pulsed gradient spin echo (PGSE) NMR was used to directly measure the kinetics of poly(ethylene) glycol (PEG) shedding from siRNA encapsulated LNPs in rat serum. The method represents a molecularly specific, real-time, quantitative, and label-free way to monitor the behavior of a nanoparticle surface coating. We believe that this method has broad implications in gaining mechanistic insights into how nanoparticle-based drug delivery vehicles behave in biofluids and is versatile enough to be applied to a diversity of systems.
Assuntos
Análise Química do Sangue/métodos , Lipídeos/química , Espectroscopia de Ressonância Magnética , Nanopartículas/química , Polietilenoglicóis/análise , RNA Interferente Pequeno/química , Animais , Lipossomos/química , Masculino , RatosRESUMO
Myeloperoxidase (MPO) is a heme-containing peroxidase from phagocytic cells, which plays an important role in the innate immune response. The primary anti-microbial function of MPO is achieved by catalyzing the oxidation of halides by hydrogen peroxide (H2O2). Upon activation of phagocytes, MPO activity is detectable in both phagosomes and extracellularly, where it can remain or transcytose into interstitial compartments. Activated MPO leads to oxidative stress and tissue damage in many inflammatory states, including cardiovascular disease. Starting from a low molecular weight (LMW) high throughput screening (HTS) hit, here we report the discovery of a novel pyrrolidinone indole (IN-4) as a highly potent MPO inhibitor. This compound displays similar in vitro potency across peroxidation, plasma and NETosis assays. In a dilution/dialysis study, <5% of the original MPO activity was detected post-incubation of MPO with IN-4, suggesting irreversible enzyme inhibition. A fast MPO inactivation rate (kinact/Ki) and low partition ratio (k3/k4) make IN-4 kinetic properties attractive for an MPO inhibitor. This compound also displays significant selectivity over the closely related thyroid peroxidase (TPO), and is selective for extracellular MPO over intracellular (neutrophil) MPO. Moreover, IN-4 shows good exposure, low clearance and high oral bioavailability in mice, rats and dogs. The high in vitro MPO activity and high oral exposure observed with IN-4 result in a dose-dependent inhibition of MPO activity in three mouse models of inflammation. In conclusion, IN-4 is a novel, potent, mechanism-based and selective MPO inhibitor, which may be used as superior therapeutic agent to treat multiple inflammatory conditions, including cardiovascular disease.