Role of TLR4/MyD88/NF‑κB signaling in the contrast‑induced injury of renal tubular epithelial cells

Abstract

The aim of the present study was to explore the role of toll-like receptor 4 (TLR4)/myeloid differentiation primary response 88 (MyD88)/nuclear factor (NF)-κB signaling in the contrast-induced injury of renal tubular epithelial cells, and to investigate the potential mechanisms. HK-2 cells cultured in vitro were randomly divided into six groups as follows: i) The blank group; ii) the iohexol group; iii) the NF-κB RNAi group (NF-κB siRNA + iohexol); iv) the TLR4 RNAi group (TLR4 siRNA + iohexol); v) the NF-κB blocker group (PDTC + iohexol); and vi) the TLR4 blocker group (CLI-095 + iohexol). The expression of the TLR4/MyD88/NF-κB signaling pathway proteins was detected by reverse transcription-quantitative (RT-q)PCR and western blot analysis, and the cellular proliferation rate was determined using the Cell Counting Kit-8 assay. The mRNA expression levels of the inflammatory cytokines tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 were also detected using RT-qPCR, and apoptosis was assessed by flow cytometry and western blotting to detect apoptosis-associated proteins (caspase-3, caspase-9 and cleaved caspase-9). Compared with the blank group, the apoptotic rates and the expression levels of TLR4, MyD88, NF-κB, caspase-3, cleaved caspase-9, TNF-α, IL-1β and IL-6 were upregulated in the iohexol group (P<0.001). However, when TLR4 or NF-κB were blocked or silenced, these effects were reversed (P<0.001). Collectively, the results of the present study indicated that TLR4/MyD88/NF-κB signaling is involved in the contrast-induced injury of renal tubular epithelial cells by inducing inflammation and apoptosis.

Kluyveromyces marxianus Ameliorates High-Fat-Diet-Induced Kidney Injury by Affecting Gut Microbiota and TLR4/NF-κB Pathway in a Mouse Model

“…13 Cellular Microbiology cytokine levels of IL-1β and IL-6, which is consistent with the report that K. marxianus has anti-inflammatory potential [44], and its treatment may be beneficial to improve gut inflammation since gut is a source of inflammation in CHD [48]. The inflammatory TLR4/NF-κB axis promotes KI development and progression [14,49], and the inhibition of the signaling pathways has been widely reported to control KI development [15,50]. The present findings also approved that K. marxianus treatment shows protective function for KI by downregulating the expression of TLR4/ NF-κB (Figure 9).…”

Toll-Like Receptors in Acute Kidney Injury

“…Furthermore, in MyD88−/− mice, the anti-apoptotic bcl-2 protein is elevated compared to wild type mice, which results in protection from death [82]. In vitro analyses confirmed the notion that TLR4/MyD88/NF-κB axis regulates inflammatory response and apoptosis after renal injury [89]. In the context of renal damage, TLR4 can be activated by alarmins (endogenous ligands for TLR4; i.e., HGMB1 and Hsp70) as a consequence of cellular stress, amplifying kidney injury [90].…”

Identification and validation of hub genes in drug induced acute kidney injury basing on integrated transcriptomic analysis

“…By promoting inflammation, programmed cell death, and endoplasmic reticulum stress, TLR4 has been linked to several acute and chronic renal disorders ( 34 ). Studies on contrast-induced AKI have found that contrast media increased the expression of TLR4 and up-regulate TLR4-related downstream inflammatory pathways ( 35 , 36 ). Ginsenoside Rb1/atorvastatin both attenuate renal injury by inhibiting the activation of TLR4)/NF-κB signaling pathway triggered by contrast media ( 37 , 38 ).…”