Targeting PPARγ-NF-κB: (+)-catechin reverses Clostridioides difficile toxin A-induced intestinal barrier dysfunction.

BACKGROUND: Clostridioides difficile toxin A (TcdA) is a key factor in antibiotic-associated intestinal epithelial injury. (+)-Catechin (CC) exhibits anti-inflammatory and antioxidant properties, but its role in protecting intestinal epithelial barrier function during TcdA exposure remains unclear. METHODS: Human colon epithelial Caco-2 cells were treated with TcdA to induce barrier dysfunction, followed by CC at varying concentrations. Barrier integrity was assessed using trans-epithelial electrical resistance (TEER), Lucifer yellow paracellular flux, and lactate dehydrogenase (LDH) release. The involvement of peroxisome proliferator-activated receptor gamma (PPARγ) and nuclear factor kappa B (NF-κB) signaling was evaluated using short hairpin RNA (shRNA)-mediated PPARγ knockdown. RESULTS: TcdA treatment disrupted Caco-2 barrier function, indicated by decreased TEER, increased Lucifer yellow flux, and elevated LDH release. TcdA treatment also reduced PPARγ expression and was associated with increased activation of the NF-κB signaling pathway. CC treatment significantly alleviated these effects in a concentration-dependent manner, with 100 μg/mL showing optimal protection. PPARγ knockdown partially attenuated the protective effects of CC and diminished its inhibitory effect on NF-κB activation, suggesting that PPARγ contributes to the barrier-protective role of CC. CONCLUSION: CC attenuates TcdA-induced intestinal epithelial barrier dysfunction and is associated with modulation of the PPARγ-NF-κB signaling pathway.