RESUMEN
Dopamine is an important neurotransmitter that regulates numerous essential functions, including cognition and voluntary movement. As such, it serves as an important scaffold for synthesis of novel analogues as part of drug development effort to obtain drugs for treatment of neurodegenerative diseases, such as Parkinson's disease. To that end, similarity search of the ZINC database based on two known dopamine-1 receptor (D1R) agonists, dihydrexidine (DHX) and SKF 38393, respectively, was used to predict novel chemical entities with potential binding to D1R. Three compounds that showed the highest similarity index were selected for synthesis and bioactivity profiling. All main synthesis products as well as the isolated intermediates, were properly characterized. The physico-chemical analyses were performed using HRESIMS, GC/MS, LC/MS with UV-Vis detection, and FTIR, 1H NMR and 13C NMR spectroscopy. Binding to D1 and D2 receptors and inhibition of dopamine reuptake via dopamine transporter were measured for the synthesized analogues of DHX and SKF 38393.
Asunto(s)
Catecolaminas , Receptores de Dopamina D1 , 2,3,4,5-Tetrahidro-7,8-dihidroxi-1-fenil-1H-3-benzazepina/farmacología , Fenantridinas/farmacología , Receptores de Dopamina D1/metabolismoRESUMEN
Yes-associated protein (YAP) and PDZ-binding motif (TAZ) have emerged as important regulators of pathologic fibroblast activation in fibrotic diseases. Agonism of Gαs-coupled G protein coupled receptors (GPCRs) provides an attractive approach to inhibit the nuclear localization and function of YAP and TAZ in fibroblasts that inhibits or reverses their pathological activation. Agonism of the dopamine D1 GPCR has proven effective in preclinical models of lung and liver fibrosis. However, the molecular mechanisms coupling GPCR agonism to YAP and TAZ inactivation in fibroblasts remain incompletely understood. Here, using human lung fibroblasts, we identify critical roles for the cAMP effectors EPAC1/2, the small GTPase RAP2c, and the serine/threonine kinase MAP4K7 as the essential elements in the downstream signaling cascade linking GPCR agonism to LATS1/2-mediated YAP and TAZ phosphorylation and nuclear exclusion in fibroblasts. We further show that this EPAC/RAP2c/MAP4K7 signaling cascade is essential to the effects of dopamine D1 receptor agonism on reducing fibroblast proliferation, contraction, and extracellular matrix production. Targeted modulation of this cascade in fibroblasts may prove a useful strategy to regulate YAP and TAZ signaling and fibroblast activities central to tissue repair and fibrosis.
Asunto(s)
Fibroblastos/enzimología , Factores de Intercambio de Guanina Nucleótido/metabolismo , Receptores de Dopamina D1/metabolismo , Proteínas Coactivadoras Transcripcionales con Motivo de Unión a PDZ/metabolismo , Proteínas Señalizadoras YAP/metabolismo , Proteínas ras/metabolismo , Células Cultivadas , Agonistas de Dopamina/farmacología , Fibroblastos/efectos de los fármacos , Fibroblastos/patología , Fibrosis , Factores de Intercambio de Guanina Nucleótido/genética , Humanos , Fenantridinas/farmacología , Fosforilación , Proteínas Serina-Treonina Quinasas/metabolismo , Receptores de Dopamina D1/agonistas , Transducción de Señal , Proteínas Coactivadoras Transcripcionales con Motivo de Unión a PDZ/genética , Proteínas Señalizadoras YAP/genética , Proteínas ras/genéticaRESUMEN
Levodopa is the standard-of-care for Parkinson's disease, but continued loss of dopamine neurons with disease progression decreases its bioconversion to dopamine, leading to increased side effects and decreased efficacy. In theory, dopamine agonists could equal levodopa, but no approved oral "dopamine agonist" matches the efficacy of levodopa. There are consistent data in both primate models and in Parkinson's disease showing that selective high intrinsic activity D1 agonists can equal levodopa in efficacy. There are, however, no data on whether such compounds would be effective in severe disease when levodopa efficacy is low or absent. We compared two approved antiparkinson drugs (levodopa and the D2/3 agonist bromocriptine) with the experimental selective D1 full agonist dihydrexidine in two severely parkinsonian MPTP-treated non-human primates. Bromocriptine caused no discernible improvement in parkinsonian signs, whereas levodopa caused a small transient improvement in one of the two subjects. Conversely, the full D1 agonist dihydrexidine caused a dramatic improvement in both subjects, decreasing parkinsonian signs by ca. 75%. No attenuation of dihydrexidine effects was observed when the two subjects were pretreated with the D2 antagonist remoxipride. These data provide evidence that selective D1 agonists may provide profound antiparkinson symptomatic relief even when the degree of nigrostriatal degeneration is so severe that current drugs are ineffective. Until effective disease-modifying therapies are discovered, high intrinsic activity D1 agonists may offer a major therapeutic advance in improving the quality of life, and potentially the longevity, of late stage Parkinson's patients.
Asunto(s)
Antiparkinsonianos/farmacología , Encéfalo/efectos de los fármacos , Agonistas de Dopamina/farmacología , Levodopa/farmacología , Actividad Motora/efectos de los fármacos , Trastornos Parkinsonianos/tratamiento farmacológico , Fenantridinas/farmacología , Receptores de Dopamina D1/agonistas , 1-Metil-4-fenil-1,2,3,6-Tetrahidropiridina , Animales , Encéfalo/metabolismo , Encéfalo/patología , Encéfalo/fisiopatología , Bromocriptina/farmacología , Chlorocebus aethiops , Modelos Animales de Enfermedad , Masculino , Trastornos Parkinsonianos/inducido químicamente , Trastornos Parkinsonianos/metabolismo , Trastornos Parkinsonianos/fisiopatología , Receptores de Dopamina D1/metabolismo , Receptores de Dopamina D2/agonistas , Receptores de Dopamina D2/metabolismoRESUMEN
Medications that enhance dopaminergic neurotransmission can be useful in the pharmacotherapy of posttraumatic stress disorder (PTSD), which manifests as fearful memory retrieval, anxiety and depression. We examined the effects of subchronic (15 days) treatment with select dopaminergic medications, including bromocriptine, modafinil, dihydrexidine, rotigotine and pramipexole, in a mouse model of PTSD induced by single prolonged stress (mSPS). The potential antidepressant-like and anxiolytic effects of the medications were measured by the forced swim test (FST) and the elevated plus maze (EPM) test, respectively. In addition, we studied the effects of these medications on memory retrieval in an auditory fear conditioning (FC) test, on ultrasonic vocalizations (USVs) induced by restraint stress, and on spontaneous locomotor activity (SLA). We report that a single exposure to a severe and complex set of stressors several days before testing increased immobility time in the FST and freezing in the FC paradigm and reduced the time spent in the open arms of the EPM. The stressed mice also displayed increased USVs, especially the short type. While none of the tested dopamine-mimetics exhibited anxiolytic-like effects, rotigotine produced antidepressant-like activity specifically in the mSPS-exposed animals. Moreover, both rotigotine and pramipexole shortened the duration of freezing in the fear conditioning test, but only in the mSPS-exposed mice. This study supports the hypothesis that the activation of dopaminergic D2/D3 receptors may be a promising pharmacotherapy for PTSD.