Klotho expression is reduced in COPD airway epithelial cells: effects on inflammation and oxidant injury.
Bottom Line: Moreover, the effect of KL on CSE-mediated inflammation and hydrogen peroxide-induced cellular injury/apoptosis was determined using siRNAs.CSE and TNFα (tumour necrosis factor α) decreased KL expression and release from airway epithelial cells, which was associated with enhanced pro-inflammatory cytokine expression.These effects involved the NF-κB (nuclear factor κB), MAPK (mitogen-activated protein kinase) and Nrf2 (nuclear factor erythroid 2-related factor 2) pathways.
Affiliation: Department of Respiratory Medicine, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029, China.Show MeSH
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Mentions: The effect of KL knockdown on oxidative damage was also assessed. Cells depleted of KL by using siRNA3 produced more ROS in response to 200 μM H2O2 than those treated with control siRNA (Figure 7A). Apoptosis was also significantly increased by KL knockdown in the presence of 200 μM H2O2 (Figure 7B), which may account for the reduced cell viability observed in response to 5% CSE (Figure 7C). An enhanced activation of Akt/PKB (protein kinase B), p38 MAPK and ERK1/2 pathways was observed in the presence of KL knockdown under the conditions of oxidative stress (Figure 8A and 8B). Furthermore, KL knockdown significantly accelerated Nrf2 (nuclear factor erythroid 2-related factor 2) consumption and reduced the ability of the cells to induce an endogenous antioxidant response, as measured by total Nrf2 expression and nuclear localization (Figure 8C). Our results suggest that the lack of intercellular KL increased sensitivity to oxidative stress and exacerbated cellular injury in bronchial epithelial cells.
Affiliation: Department of Respiratory Medicine, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029, China.