Background: Clostridium difficile infections (CDIs) caused by Clostridium difficile toxin A (TcdA) lead to severe ulceration, inflammation and bleeding of the colon, and are difficult to treat. Aim: The study aimed to evaluate the effect of rifaximin on TcdA-induced apoptosis in intestinal epithelial cells and investigate the role of PXR in its mechanism of action. Methods: Caco‐2 cells were incubated with TcdA and treated with rifaximin (0.1−10 μM) with or without ketoconazole (10 μM). The transepithelial electrical resistance (TEER) and viability of the treated cells was determined. Also, the expression of zona occludens‐1 (ZO‐1), toll‐like receptor 4 (TLR4), Bcl‐2‐associated X protein (Bax), transforming growth factor‐β‐activated kinase‐1 (TAK1), myeloid differentiation factor 88 (MyD88) and nuclear factor‐kappaB (NF‐κB) was determined. Results Rifaximin treatment (0.1, 1.0 and 10 μM) caused a significant and concentration-dependent increase in the TEER of Caco-2 cells (360%, 480% and 680% vs TcdA treatment) 24 hours after the treatment and improved their viability (61%, 79% and 105%). Treatment also concentration-dependently decreased the expression of Bax protein (–29%, –65% and –77%) and increased the expression of ZO-1 (25%, 54% and 87%) and occludin (71%, 114% and 262%) versus TcdA treatment. The expression of TLR4 (–33%, –50% and –75%), MyD88 (–29%, –60% and –81%) and TAK1 (–37%, –63% and –79%) were also reduced with rifaximin versus TcdA treatment. Ketoconazole treatment inhibited these effects. Conclusions: Rifaximin improved TcdA‐induced toxicity in Caco‐2 cells by the PXR‐dependent TLR4/MyD88/NF‐κB pathway mechanism, and may be useful in the treatment of CDIs.

Rifaximin improves Clostridium difficile toxin A-induced toxicity in Caco-2 cells by the PXR-dependent TLR4/MyD88 /NF-?B pathway / Esposito, Giuseppe; Nobile, Nicola; Gigli, Stefano; Seguella, Luisa; Pesce, Marcella; D'Alessandro, Alessandra; Bruzzese, Eugenia; Capoccia, Elena; Steardo, Luca; Cuomo, Rosario; Sarnelli, Giovanni. - In: FRONTIERS IN PHARMACOLOGY. - ISSN 1663-9812. - 7:May(2016). [10.3389/fphar.2016.00120]

Rifaximin improves Clostridium difficile toxin A-induced toxicity in Caco-2 cells by the PXR-dependent TLR4/MyD88 /NF-?B pathway

PESCE, MARCELLA;D'ALESSANDRO, ALESSANDRA;BRUZZESE, EUGENIA;CUOMO, ROSARIO;SARNELLI, GIOVANNI
2016

Abstract

Background: Clostridium difficile infections (CDIs) caused by Clostridium difficile toxin A (TcdA) lead to severe ulceration, inflammation and bleeding of the colon, and are difficult to treat. Aim: The study aimed to evaluate the effect of rifaximin on TcdA-induced apoptosis in intestinal epithelial cells and investigate the role of PXR in its mechanism of action. Methods: Caco‐2 cells were incubated with TcdA and treated with rifaximin (0.1−10 μM) with or without ketoconazole (10 μM). The transepithelial electrical resistance (TEER) and viability of the treated cells was determined. Also, the expression of zona occludens‐1 (ZO‐1), toll‐like receptor 4 (TLR4), Bcl‐2‐associated X protein (Bax), transforming growth factor‐β‐activated kinase‐1 (TAK1), myeloid differentiation factor 88 (MyD88) and nuclear factor‐kappaB (NF‐κB) was determined. Results Rifaximin treatment (0.1, 1.0 and 10 μM) caused a significant and concentration-dependent increase in the TEER of Caco-2 cells (360%, 480% and 680% vs TcdA treatment) 24 hours after the treatment and improved their viability (61%, 79% and 105%). Treatment also concentration-dependently decreased the expression of Bax protein (–29%, –65% and –77%) and increased the expression of ZO-1 (25%, 54% and 87%) and occludin (71%, 114% and 262%) versus TcdA treatment. The expression of TLR4 (–33%, –50% and –75%), MyD88 (–29%, –60% and –81%) and TAK1 (–37%, –63% and –79%) were also reduced with rifaximin versus TcdA treatment. Ketoconazole treatment inhibited these effects. Conclusions: Rifaximin improved TcdA‐induced toxicity in Caco‐2 cells by the PXR‐dependent TLR4/MyD88/NF‐κB pathway mechanism, and may be useful in the treatment of CDIs.
2016
Rifaximin improves Clostridium difficile toxin A-induced toxicity in Caco-2 cells by the PXR-dependent TLR4/MyD88 /NF-?B pathway / Esposito, Giuseppe; Nobile, Nicola; Gigli, Stefano; Seguella, Luisa; Pesce, Marcella; D'Alessandro, Alessandra; Bruzzese, Eugenia; Capoccia, Elena; Steardo, Luca; Cuomo, Rosario; Sarnelli, Giovanni. - In: FRONTIERS IN PHARMACOLOGY. - ISSN 1663-9812. - 7:May(2016). [10.3389/fphar.2016.00120]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/633247
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