Efeito protetor de Cecropia pachystachya contra a citotoxidade do preproIAPP é independente da homeostasia do Ca2+: conhecimento revelado por um modelo de levedura de desregulação de Ca2+ mediada pelo preproIAPP
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2021
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Edições Universitárias Lusófonas
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Apesar dos avanços na terapêutica, a diabetes tipo 2 é uma epidemia com números alarmantes a nível mundial. Novas estratégias de prevenção e tratamentos são imperativas. Um potencial alvo de investigação é a agregação do Polipéptido Amilóide dos Ilhéus (IAPP), um dos responsáveis pela disfunção das células-ß pancreáticas. Para estudar o impacto do IAPP na sinalização do cálcio (Ca2+), desenvolvemos um modelo de levedura com um duplo sistema de reporte que, de forma independente, expressa preproIAPP (ppIAPP) e possui o gene lacZ sob o controlo da região promotora do Crz1. Neste sistema, o ppIAPP induziu uma ativação exacerbada do Crz1, um fator de transcrição ativado pela via Ca2+/calmodulina/calcineurina. Com base nos efeitos medicinais descritos para plantas Urticaceae, testámos o potencial protetor de Cecropia pachystachya contra a citotoxicidade induzida pelo IAPP no modelo de levedura desenvolvido. Embora o extrato de C. pachystachya não tenha atenuado a toxicidade do ppIAPP, o tratamento com a fração enriquecida de C. pachystachya (EFF-Cp) melhorou significativamente a viabilidade celular. A bioatividade do extrato e fração de C. pachystachya na regulação da homeostasia do Ca2+ foi também avaliada. Nenhum dos tratamentos impediu a ativação do Crz1, sugerindo que a proteção conferida pela EFF-Cp contra a toxicidade do ppIAPP é mediada por mecanismos independentes do Ca2+. Palavras-chave: Amilina; Cecropia pachystachya; Diabetes; Polipéptido Amilóide dos Ilhéus (IAPP); Sinalização do cálcio
Despite the progresses in therapeutics, type 2 diabetes is still an epidemic with alarming numbers worldwide. New strategies for prevention and treatments are imperative. A venue of research with potential is the aggregation of Islet Amyloid PolyPeptide (IAPP), a contributor to pancreatic β-cell dysfunction. To address the impact of IAPP on calcium (Ca2+) signalling, we developed a dual reporter yeast model independently expressing preproIAPP-GFP (ppIAPP) and encoding the lacZ gene under the control of Crz1-recognition elements. In this reporter system, ppIAPP induced Crz1 hyperactivation, a yeast transcription factor activated by the Ca2+/calmodulin/calcineurin pathway, which was followed by the increase in β-galactosidase activity. Encouraged by the reported healthy effects of Urticaceae plants against metabolic disturbances, we tested the protective potential of Cecropia pachystachya against IAPP-induced cytotoxicity using the newly designed yeast model. Although C. pachystachya extract exerted no beneficial effects towards the prevention of ppIAPP cytotoxicity, treatment with C. pachystachya enriched C-glycosyl flavonoid fraction (EFF-Cp) significantly improved viability of ppIAPP-expressing cells. Potential bioactivities of C. pachystachya extract and EFF-Cp towards the restoration of Ca2+ homeostasis disrupted by ppIAPP expression were also assessed. Neither prevented Crz1 hyperactivation, suggesting that the EFF-Cp-induced protection against ppIAPP toxicity was mediated by Ca2+-independent mechanisms. Keywords: Amylin, Calcium signaling; Cecropia pachystachya; Diabetes; Islet Amyloid Polypeptide (IAPP)
Despite the progresses in therapeutics, type 2 diabetes is still an epidemic with alarming numbers worldwide. New strategies for prevention and treatments are imperative. A venue of research with potential is the aggregation of Islet Amyloid PolyPeptide (IAPP), a contributor to pancreatic β-cell dysfunction. To address the impact of IAPP on calcium (Ca2+) signalling, we developed a dual reporter yeast model independently expressing preproIAPP-GFP (ppIAPP) and encoding the lacZ gene under the control of Crz1-recognition elements. In this reporter system, ppIAPP induced Crz1 hyperactivation, a yeast transcription factor activated by the Ca2+/calmodulin/calcineurin pathway, which was followed by the increase in β-galactosidase activity. Encouraged by the reported healthy effects of Urticaceae plants against metabolic disturbances, we tested the protective potential of Cecropia pachystachya against IAPP-induced cytotoxicity using the newly designed yeast model. Although C. pachystachya extract exerted no beneficial effects towards the prevention of ppIAPP cytotoxicity, treatment with C. pachystachya enriched C-glycosyl flavonoid fraction (EFF-Cp) significantly improved viability of ppIAPP-expressing cells. Potential bioactivities of C. pachystachya extract and EFF-Cp towards the restoration of Ca2+ homeostasis disrupted by ppIAPP expression were also assessed. Neither prevented Crz1 hyperactivation, suggesting that the EFF-Cp-induced protection against ppIAPP toxicity was mediated by Ca2+-independent mechanisms. Keywords: Amylin, Calcium signaling; Cecropia pachystachya; Diabetes; Islet Amyloid Polypeptide (IAPP)
Descrição
Biomedical and biopharmaceutical research : jornal de investigação biomédica e biofarmacêutica
Palavras-chave
CIÊNCIAS FARMACÊUTICAS, DIABETES TIPO 2, CÁLCIO, PHARMACEUTICAL SCIENCES, TYPE 2 DIABETES, CALCIUM