RESUMO
Aniridia is a panocular disease causing progressive severe visual impairment and blindness due to PAX-6 haploinsufficiency. One of the most disabling ocular symptoms is aniridia-related keratopathy (ARK), a progressive corneal opacification due to epithelial impairment, vascular and conjunctival pathologies. There is currently no available treatment to prevent progressive visual loss. For this aim, we have used mutant limbal cells for phenotypic screening using FDA-approved and bio-actives drug library and found Duloxetine, a serotonin and norepinephrine reuptake inhibitor used against severe depression as able to enhance endogenous PAX6 expression and target genes, which returned fairly to amounts found in normal limbal cells. In addition, Duloxetine could restore cell migration of the mutant cells. Furthermore, we show that Duloxetine activates PAX6 through inhibition of the ERK pathway on limbal mutant cells. This observation fits the recent report that MEK inhibitors enhance PAX6 in vivo, partially rescuing aniridia developmental phenotype of Pax6+/- mice. The discovery of an unique compound able to enhance PAX6 activity and that could be locally administered using eye drops associated with drug repurposing is expected to lead to rapid development of applicable drugs for the topical (eye drops) treatment of aniridia.
Assuntos
Aniridia , Haploinsuficiência , Animais , Aniridia/genética , Cloridrato de Duloxetina/farmacologia , Proteínas do Olho/metabolismo , Sistema de Sinalização das MAP Quinases , Camundongos , Quinases de Proteína Quinase Ativadas por Mitógeno/genética , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Soluções Oftálmicas , Fator de Transcrição PAX6/genética , Transdução de Sinais , Células-Tronco/patologiaRESUMO
Aniridia is a panocular inherited rare eye disease linked to heterozygous mutations on the PAX6 gene, which fail to properly produce sufficient protein essential for normal eye development and function. Most of the patients suffer from aniridia-related keratopathy, a progressive opacification of the cornea. There is no effective treatment for this blinding disease. Here we screen for small compounds and identified Ritanserin, a serotonin 2A receptor antagonist, that can rescue PAX6 haploinsufficiency of mutant limbal cells, defective cell migration and PAX6-target gene expression. We further demonstrated that Ritanserin activates PAX6 production through the selective inactivation of the MEK/ERK signaling pathway. Our data strongly suggest that repurposing this therapeutic molecule could be effective in preventing or treating existing blindness by restoring corneal transparency.
Assuntos
Proteína Quinase 1 Ativada por Mitógeno/genética , Proteína Quinase 3 Ativada por Mitógeno/genética , Soluções Oftálmicas/farmacologia , Fator de Transcrição PAX6/genética , Ritanserina/farmacologia , Antagonistas da Serotonina/farmacologia , Células-Tronco/efeitos dos fármacos , Aniridia/tratamento farmacológico , Aniridia/genética , Aniridia/metabolismo , Aniridia/patologia , Linhagem Celular , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Reposicionamento de Medicamentos/métodos , Epitélio Corneano/efeitos dos fármacos , Epitélio Corneano/metabolismo , Epitélio Corneano/patologia , Regulação da Expressão Gênica , Células HEK293 , Haploinsuficiência , Humanos , Limbo da Córnea/efeitos dos fármacos , Limbo da Córnea/metabolismo , Limbo da Córnea/patologia , Proteína Quinase 1 Ativada por Mitógeno/antagonistas & inibidores , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/antagonistas & inibidores , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Modelos Biológicos , Fator de Transcrição PAX6/agonistas , Fator de Transcrição PAX6/metabolismo , Receptor 5-HT2A de Serotonina/genética , Receptor 5-HT2A de Serotonina/metabolismo , Transdução de Sinais/efeitos dos fármacos , Células-Tronco/metabolismo , Células-Tronco/patologiaRESUMO
Diabetic retinopathy (DR) remains a major cause of vision loss, due to macular edema, retinal ischemia and death of retinal neurons. We previously demonstrated that acute administration of glibenclamide into the vitreous, or given orally at a non-hypoglycemic dose, protected the structure and the function of the retina in three animal models that each mimic aspects of diabetic retinopathy in humans. In this pilot study, we investigated whether one year of chronic oral glibenclamide, in a non-hypoglycemic regimen (Amglidia®, 0.4 mg/kg, Ammtek/Nordic Pharma, 5 d/week), could alleviate the retinopathy that develops in the Goto-Kakizaki (GK) rat. In vivo, retinal function was assessed by electroretinography (ERG), retinal thickness by optical coherence tomography (OCT) and retinal perfusion by fluorescein and indocyanin green angiographies. The integrity of the retinal pigment epithelium (RPE) that constitutes the outer retinal barrier was evaluated by quantitative analysis of the RPE morphology on flat-mounted fundus ex vivo. Oral glibenclamide did not significantly reduce the Hb1Ac levels but still improved retinal function, as witnessed by the reduction in scotopic implicit times, limited diabetes-induced neuroretinal thickening and the extension of ischemic areas, and it improved the capillary coverage. These results indicate that low doses of oral glibenclamide could still be beneficial for the prevention of type 2 diabetic retinopathy. Whether the retinas ofpatients treated specifically with glibenclamideare less at risk of developing diabetic complications remains to be demonstrated.
