Costimulation with angiotensin II and interleukin 6 augments angiotensinogen expression in cultured human renal proximal tubular cells

Augmented intrarenal ANG II stimulates IL-6, which contributes to renal injury. The expression of intrarenal angiotensinogen (AGT) is enhanced by increased intrarenal ANG II in human renin/human AGT double transgenic mice. ANG II also augments AGT expression in hepatocytes and cardiac myocytes. However, the mechanisms underlying AGT augmentation by ANG II and the contribution of IL-6 to this system are poorly understood. This study was performed in human renal proximal tubular epithelial cells (HRPTECs) to test the hypothesis that IL-6 contributes to the upregulation of AGT expression by ANG II. Human kidney-2 (HK-2) cells, immortalized HRPTECs, were incubated with 10−7 M ANG II and/or 10 ng/ml IL-6 for up to 24 h. AGT mRNA and protein expressions were measured by real-time RT-PCR and ELISA, respectively. The activities of NF-κB and STAT3 were evaluated by Western blotting and EMSA. Stimulation with either ANG II or IL-6 did not significantly alter AGT mRNA or protein expression. In contrast, costimulation with ANG II and IL-6 significantly increased AGT mRNA and protein expressions (1.26 ± 0.10 and 1.16 ± 0.13 over control, respectively). Olmesartan, an ANG II type 1 receptor blocker, and an IL-6 receptor antibody individually inhibited this synergistic effect. NF-κB was also activated by costimulation with ANG II and IL-6. Phosphorylation and activity of STAT3 were increased by stimulation with IL-6 alone and by costimulation. The present study indicates that IL-6 plays an important role in ANG II-mediated augmentation of AGT expression in human renal proximal tubular cells.

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Reactive oxygen species blockade and action of insulin on expression of angiotensinogen gene in proximal tubular cells

Journal of Endocrinology ◽

10.1677/joe.1.05871 ◽

2004 ◽

Vol 183 (3) ◽

pp. 535-550 ◽

Cited By ~ 36

Author(s):

Tusty-Jiuan Hsieh ◽

Pierre Fustier ◽

Chih-Chang Wei ◽

Shao-Ling Zhang ◽

Janos G Filep ◽

...

Keyword(s):

High Glucose ◽

Diabetic Rat ◽

Ros Generation ◽

Ang Ii ◽

Proximal Tubular Cells ◽

Tubular Cells ◽

Gf 109203X ◽

Proximal Tubular ◽

Renal Proximal Tubular Cells ◽

Renal Proximal Tubular

We reported previously that insulin inhibits the stimulatory effect of high glucose on the expression of angiotensinogen (ANG) gene in both rat immortalized renal proximal tubular cells (IRPTCs) and non-diabetic rat renal proximal tubular cells (RPTCs), but has no effect in diabetic rat RPTCs. In the present study we investigated whether hyperglycaemia-induced resistance to the insulin-induced inhibition of expression of the ANG gene is mediated via the generation of reactive oxygen species (ROS) in RPTCs. Rat IRPTCs were cultured for 2 weeks in high-glucose (25 mM) or normal-glucose (5 mM) medium plus angiotensin II (Ang II) with or without a superoxide scavenger (tiron), or inhibitors of: NADPH oxidase (diphenylene iodinium, DPI), Ang II type 1 and 2 receptors (losartan and PD123319), angiotensin-converting enzyme (perindopril), protein kinase C (GF 109203X), or glutamine:fructose-6-phosphate amino-transferase (azaserine). Cellular generation of ROS, and ANG and renin mRNA levels were assessed by lucigenin assay and specific reverse transcriptase-PCR respectively. Phosphorylation of p44/42 mitogen-activated protein kinase (p44/42 MAPK) was evaluated by western blotting. Prolonged exposure of IRPTCs to high concentrations of glucose or Ang II evoked generation of ROS and resistance to the insulin-induced inhibition of expression of the ANG gene and of p44/42 MAPK phosphorylation. Co-incubation of IRPTCs with tiron, DPI, losartan, PD123319, perindopril, GF 109203X or azaserine prevented ROS generation, restoring the inhibitory action of insulin on ANG gene expression and on p44/42 MAPK phosphorylation. In conclusion, our studies demonstrate that blockade of both ROS generation and activation of the intrarenal renin–angiotensin system improves the inhibitory action of insulin on ANG gene expression in IRPTCs in conditions of high glucose.

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Macrophage-derived IL-6 contributes to ANG II-mediated angiotensinogen stimulation in renal proximal tubular cells

AJP Renal Physiology ◽

10.1152/ajprenal.00482.2015 ◽

2016 ◽

Vol 310 (10) ◽

pp. F1000-F1007 ◽

Cited By ~ 13

Author(s):

Ryan O'Leary ◽

Harrison Penrose ◽

Kayoko Miyata ◽

Ryousuke Satou

Keyword(s):

Culture Medium ◽

Ang Ii ◽

Proximal Tubular Cells ◽

Tubular Cells ◽

Ras Activation ◽

Stat3 Phosphorylation ◽

Proximal Tubular ◽

Renal Proximal Tubular Cells ◽

Intrarenal Ras ◽

Renal Proximal Tubular

The development of ANG II-dependent hypertension involves increased infiltration of macrophages (MΦ) and T cells into the kidney and the consequent elevation of intrarenal cytokines including IL-6, which facilitates the progression of hypertension and associated kidney injury. Intrarenal renin-angiotensin system (RAS) activation, including proximal tubular angiotensinogen (AGT) stimulation, has also been regarded as a cardinal mechanism contributing to these diseases. However, the interaction between immune cells and intrarenal RAS activation has not been fully delineated. Therefore, the present study investigated whether ANG II-treated MΦ induce AGT upregulation in renal proximal tubular cells (PTCs). MΦ were treated with 0–10−6 M ANG II for up to 48 h. PTCs were incubated with the collected medium from MΦ. In ANG II-treated MΦ, IL-6 mRNA and protein levels were increased (1.86 ± 0.14, protein level, ratio to control); moreover, IL-6 levels were higher than TNF-α and IL-1β in culture medium isolated from ANG II-treated MΦ. Elevated AGT expression (1.69 ± 0.04, ratio to control) accompanied by phosphorylated STAT3 were observed in PTCs that received culture medium from ANG II-treated MΦ. The addition of a neutralizing IL-6 antibody to the collected medium attenuated phosphorylation of STAT3 and AGT augmentation in PTCs. Furthermore, a JAK2 inhibitor also suppressed STAT3 phosphorylation and AGT augmentation in PTCs. These results demonstrate that ANG II-induced IL-6 elevation in MΦ enhances activation of the JAK-STAT pathway and consequent AGT upregulation in PTCs, suggesting involvement of an immune response in driving intrarenal RAS activity.

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IL-17A stimulates granulocyte colony-stimulating factor production via ERK1/2 but not p38 or JNK in human renal proximal tubular epithelial cells

AJP Renal Physiology ◽

10.1152/ajprenal.00113.2011 ◽

2012 ◽

Vol 302 (2) ◽

pp. F244-F250 ◽

Cited By ~ 13

Author(s):

Yuki Hirai ◽

Masayuki Iyoda ◽

Takanori Shibata ◽

Yoshihiro Kuno ◽

Mio Kawaguchi ◽

...

Keyword(s):

Tubular Epithelial Cells ◽

Rt Pcr ◽

Proximal Tubular Cells ◽

Tubular Cells ◽

Proximal Tubular Epithelial Cells ◽

Proximal Tubular ◽

Renal Proximal Tubular Cells ◽

Renal Proximal Tubular ◽

Stimulating Factor ◽

Stimulation Of

We investigated the potential role of IL-17A in the induction of granulocyte colony-stimulating factor (G-CSF), a critical granulopoietic growth factor, in human renal proximal tubular epithelial cells. Human renal proximal tubular cells (HK-2, ATCC) were used to characterize the effects of IL-17A or IL-17F on G-CSF production, using ELISA, real-time RT-PCR, and immunoblotting. The cell surface expression of IL-17 receptors (IL-17Rs) was analyzed by flow cytometry. IL-17A stimulation of proximal tubular cells led to a dose- and time-dependent increase in secreted G-CSF. This effect was dependent on mRNA transcription and protein translation. Real-time RT-PCR demonstrated that G-CSF mRNA expression reached a maximum level at 6 h following IL-17A stimulation and that this increase was dose dependent. Both IL-17RA and IL-17RC were expressed on proximal tubular cells. IL-17A also enhanced TNF-α- or IL-1β-mediated G-CSF secretion from cells. Additionally, IL-17A induced MAPK (ERK1/2 but not p38 MAPK or JNK) activation, and pharmacological inhibitors of MEK1/2 (U0126) but not of p38 MAPK (SB203580) or JNK (SP600125), significantly blocked the IL-17A-mediated G-CSF release. We demonstrated the potential ability of IL-17A to induce G-CSF in renal proximal tubular cells. It is proposed that IL-17A may play an important role in neutrophil transmigration and activation via stimulation of G-CSF in tubular injury.

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