Department of Nephrology, The key Laboratory for the Prevention and Treatment of Chronic Kidney Disease of Chongqing, Kidney Center of PLA, Xinqiao Hospital, Army Medical University (The Third Military Medical University), Chongqing 400037, PR China.
Department of Nephrology, The key Laboratory for the Prevention and Treatment of Chronic Kidney Disease of Chongqing, Kidney Center of PLA, Xinqiao Hospital, Army Medical University (The Third Military Medical University), Chongqing 400037, PR China.
Life Sci. 2019 Aug 15;231:116570. doi: 10.1016/j.lfs.2019.116570. Epub 2019 Jun 14.
Systemic inflammation is a main hallmark of chronic kidney disease (CKD), but the underlying mechanisms of pathogenesis of CKD-associated systemic inflammation is unclear. Current study was designed to investigate the relationship between indoxyl sulphate (IS) and CKD-associated systemic inflammation along with the protective effects of Klotho in CKD.
IS serum levels from patients were detected by high-performance liquid chromatography (HPLC), and Serum Klotho, IL-6 and TNF-α were measured separately by ELISA and Real-Time PCR analysis. Monocytes were incubated with or without Klotho, while the expressions of retinoic acid-inducible gene I (RIG-I) and NF-κB were analyzed through Western blot assay. Heterozygous kl/kl (kl/+) mice or WT mice were treated with 5/6 renal damage. Thereafter, the CKD mice were intraperitoneally injected with recombinant Klotho protein or PBS.
It shows that in 286 CKD patients, the serum levels of inflammatory factors were positively related with IS, but negatively related with Klotho. Klotho significantly inhibited IS-induced RIG-I/NF-κB activation and productions of both IL-6 and TNF-α in cultured monocytes. In vivo, along with the increase of IS and decrease of Klotho in the serum, the activation of RIG-I/NF-κB signaling was observed in peripheral blood monocytes in both CKD mice and patients. Notably, higher levels of IL-6 and TNF-α were detected in kl+/- mice given CKD. Klotho administration has evidently attenuated RIG-I/NF-κB activation in monocytes and systemic inflammation in CKD mice.
The findings suggest that Klotho can suppress CKD-associated systemic inflammation through inhibiting IS-induced RIG-1/NF-κB activation and monocyte inflammatory factor release.
全身性炎症是慢性肾脏病（CKD）的主要标志，但 CKD 相关全身性炎症的发病机制尚不清楚。本研究旨在探讨硫酸吲哚酚（IS）与 CKD 相关全身性炎症的关系，以及 Klotho 在 CKD 中的保护作用。
采用高效液相色谱法（HPLC）检测患者血清中 IS 水平，ELISA 和实时 PCR 分析分别检测血清 Klotho、IL-6 和 TNF-α。用 Klotho 孵育单核细胞，通过 Western blot 分析检测视黄酸诱导基因 I（RIG-I）和 NF-κB 的表达。杂合型 kl/kl（kl/+）小鼠或 WT 小鼠接受 5/6 肾损伤治疗。此后，将 CKD 小鼠用重组 Klotho 蛋白或 PBS 腹腔注射。
在 286 例 CKD 患者中，炎症因子的血清水平与 IS 呈正相关，与 Klotho 呈负相关。Klotho 显著抑制 IS 诱导的 RIG-I/NF-κB 激活及培养单核细胞中 IL-6 和 TNF-α的产生。在体内，随着血清中 IS 的增加和 Klotho 的减少，在 CKD 小鼠和患者的外周血单核细胞中观察到 RIG-I/NF-κB 信号的激活。值得注意的是，在给予 CKD 的 kl+/- 小鼠中检测到更高水平的 IL-6 和 TNF-α。Klotho 给药明显减弱了 CKD 小鼠单核细胞中 RIG-I/NF-κB 的激活和全身性炎症。
这些发现表明，Klotho 可通过抑制 IS 诱导的 RIG-1/NF-κB 激活和单核细胞炎症因子释放来抑制 CKD 相关的全身性炎症。
