The project of the PhD focused the attention on Paraoxonase2 (PON2), an antioxidant enzymes that is part of the PONs family. Oxidative stress and inflammation selectively affect the expression of PON2, which suggests their potential implication in inflammatory bowel disease (IBD), however its role in the intestinal tract and the dietary factors involved in its modulation remain unclear. The aim of my thesis was investigate the effect of high-glucose (HG) chronic exposure on PON2 modulation. It is know that hyperglycaemia is involved in the development gastrointestinal diseases. In the first part of my thesis to better characterize this cell model, CaCo-2 cells were treated in HG concentration (50mM) or physiological glucose condition (25mM) at 4h, 24, 48h and 1 week. Results showed that HG-treatment induced a significant time-dependent increase in glyco-oxidation with a significantly decrease in total antioxidant intracellular defence. A decrease in PON2 mRNA levels, protein expression and activity were observed after treatment. Moreover, chronic HG-treatment was able to induced the intrinsic and extrinsic apoptotic pathway, suppress autophagy and altered metabolic profile and mitochondria. The second part of my thesis aimed to investigate the potential positive effect of polyphenols from apples on PON2 and glyco-oxidative stress in intestinal cells. Polyphenols was extracted from Calvilla White Winter and Golden Delicious apples. Calville W.W and pure compound phloretin showed the best antioxidant ant anti-glycative results. Moreover, chronic HG-cells treated with polyphenols showed an increase in PON2 expression and activity with a conseguent decrease of glyco-oxidative damage, an improved mitochondrial function and the inhibition of apoptotic pathways. The effect was related to the quantitative and qualitative polyphenols content. In conclusion, the results could be useful to understand the diet modulation of PON2 and its role in intestinal cells dysfunction.
Il mio progetto di dottorato ha focalizzato l'attenzione sulla paraoxonase-2 (PON2), un enzima antiossidante che fa parte della famiglia PONs. E’ noto che lo stress ossidativo e l'infiammazione ne influenzano l'espressione, il che suggerisce una potenziale implicazione nella malattie infiammatorie intestinali (IBD). Tuttavia il suo ruolo a livello intestinale e i fattori dietetici coinvolti nella sua modulazione rimangono poco chiari. Lo scopo della mia tesi è stato studiare l'effetto dell'esposizione cronica ad alte concentrazioni di glucosio (HG) sulla modulazione di PON2. È noto che l'iperglicemia è coinvolta nello sviluppo di malattie gastrointestinali. Nella prima parte della mia tesi per caratterizzare questo modello cellulare, le cellule intestinali CaCo-2 sono state trattate in alte concentrazione di glucosio (50 mM) o in condizioni fisiologiche (25 mM) per 4, 24, 48 ore e 1 settimana. I risultati hanno mostrato che il trattamento HG ha indotto un significativo aumento tempo dipendente della glico-ossidazione con una significativa riduzione delle difese antiossidanti totali. HG ha ridotto significativamente i livelli di mRNA, l’ espressione proteica e l’ attività della PON2. Inoltre il trattamento è stato in grado di indurre la via apoptotica intrinseca ed estrinseca, inibire l'autofagia, alterare il profilo metabolico ed i mitocondri. Nella seconda parte della mia tesi, utilizzando lo stesso modello cellulare ho indagato l’ effetto dei polifenoli di mela nella modulazione della PON2 e sullo stress glico-ossidativo. I polifenoli sono stati estratti dalle mele Calvilla White Winter e Golden Delicious. Calville W.W e la floretina hanno mostrato migliori capacità anti-ossidanti ed anti-glicative. Inoltre, le cellule-HG trattate con i polifenoli hanno mostrato un aumento dell'espressione e dell'attività di PON2 con una conseguente riduzione del danno glico-ossidativo, una migliore funzione mitocondriale e l'inibizione delle vie apoptotiche. L'effetto era correlato al contenuto ed alla tipologia di polifenoli. In conclusione, i risultati potrebbero essere utili per comprendere in che modo la dieta modula la PON2 ed il suo ruolo nella disfunzione delle cellule intestinali.
Role of Paraoxonase2 in intestinal cells and its modulation by dietary factors / Morresi, Camilla. - (2020 Mar 24).
Role of Paraoxonase2 in intestinal cells and its modulation by dietary factors
MORRESI, CAMILLA
2020-03-24
Abstract
The project of the PhD focused the attention on Paraoxonase2 (PON2), an antioxidant enzymes that is part of the PONs family. Oxidative stress and inflammation selectively affect the expression of PON2, which suggests their potential implication in inflammatory bowel disease (IBD), however its role in the intestinal tract and the dietary factors involved in its modulation remain unclear. The aim of my thesis was investigate the effect of high-glucose (HG) chronic exposure on PON2 modulation. It is know that hyperglycaemia is involved in the development gastrointestinal diseases. In the first part of my thesis to better characterize this cell model, CaCo-2 cells were treated in HG concentration (50mM) or physiological glucose condition (25mM) at 4h, 24, 48h and 1 week. Results showed that HG-treatment induced a significant time-dependent increase in glyco-oxidation with a significantly decrease in total antioxidant intracellular defence. A decrease in PON2 mRNA levels, protein expression and activity were observed after treatment. Moreover, chronic HG-treatment was able to induced the intrinsic and extrinsic apoptotic pathway, suppress autophagy and altered metabolic profile and mitochondria. The second part of my thesis aimed to investigate the potential positive effect of polyphenols from apples on PON2 and glyco-oxidative stress in intestinal cells. Polyphenols was extracted from Calvilla White Winter and Golden Delicious apples. Calville W.W and pure compound phloretin showed the best antioxidant ant anti-glycative results. Moreover, chronic HG-cells treated with polyphenols showed an increase in PON2 expression and activity with a conseguent decrease of glyco-oxidative damage, an improved mitochondrial function and the inhibition of apoptotic pathways. The effect was related to the quantitative and qualitative polyphenols content. In conclusion, the results could be useful to understand the diet modulation of PON2 and its role in intestinal cells dysfunction.File | Dimensione | Formato | |
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