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Tweak induces proliferation in renal tubular epithelium: a role in uninephrectomy induced renal hyperplasia.

Sanz AB, Sanchez-Niño MD, Izquierdo MC, Jakubowski A, Justo P, Blanco-Colio LM, Ruiz-Ortega M, Egido J, Ortiz A - J. Cell. Mol. Med. (2009)

Bottom Line: In this regard, TWEAK knock-out mice with AKI displayed less tubular apoptosis and proliferation, as well as improved renal function.In conclusion, TWEAK actions in tubular cells are context dependent.This may be relevant for compensatory renal hyperplasia following nephrectomy.

View Article: PubMed Central - PubMed

Affiliation: Fundación Jiménez Díaz, Universidad Autónoma de Madrid, Fundación Renal Iñigo Alvarez de Toledo, Madrid, Spain.

ABSTRACT
The tumour necrosis factor (TNF) family member TWEAK activates the Fn14 receptor and has pro-apoptotic, proliferative and pro-inflammatory actions that depend on the cell type and the microenvironment. We explored the proliferative actions of TWEAK on cultured tubular cells and in vivo on renal tubules. Additionally, we studied the role of TWEAK in compensatory proliferation following unilateral nephrectomy and in an inflammatory model of acute kidney injury (AKI) induced by a folic acid overdose. TWEAK increased the proliferation, cell number and cyclin D1 expression of cultured tubular cells, in vitro. Exposure to serum increased TWEAK and Fn14 expression and the proliferative response to TWEAK. TWEAK activated the mitogen-activated protein kinases ERK and p38, the phosphatidyl-inositol 3-kinase (PI3K)/Akt pathway and NF-kappaB. TWEAK-induced proliferation was prevented by inhibitors of these protein kinases and by the NF-kappaB inhibitor parthenolide. TWEAK-induced tubular cell proliferation as assessed by PCNA and cyclin D1 expression in the kidneys of adult healthy mice in vivo. By contrast, TWEAK knock-out mice displayed lower tubular cell proliferation in the remnant kidney following unilateral nephrectomy, a non-inflammatory model. This is consistent with TWEAK-induced proliferation on cultured tubular cells in the absence of inflammatory cytokines. Consistent with our previously published data, in the presence of inflammatory cytokines TWEAK promoted apoptosis, not proliferation, of cultured tubular cells. In this regard, TWEAK knock-out mice with AKI displayed less tubular apoptosis and proliferation, as well as improved renal function. In conclusion, TWEAK actions in tubular cells are context dependent. In a non-inflammatory milieu TWEAK induces proliferation of tubular epithelium. This may be relevant for compensatory renal hyperplasia following nephrectomy.

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TWEAK increases cell proliferation in cultured murine (A–D) and human (E) renal tubular cells. (A) and (B) Quantification by flow cytometry of tubular cell number following treatment with TWEAK: (A) Time–response to 100 ng/ml TWEAK in serum-deprived cells, **P < 0.005 versus its corresponding control; *P < 0.05 versus control. Mean (±S.E.M.) of four independent experiments. (B) Dose–response at 18 hrs, *P < 0.02 versus 0% FBS. Mean (±S.E.M.) of four independent experiments. Cells cultured in 5% FBS medium were used as positive controls. (C) Treatment with 100 ng/ml TWEAK for 18 hrs induced cell proliferation (flow cytometry of DNA content). Note the increased proportion of cells in the S and M phase of the cell cycle (/––––/), without changes in the apoptotic rate (arrow). Mean (±S.E.M.) of four experiments, *P < 0.002 versus control. (D) ITEM-4, a neutralizing anti-Fn14 antibody and an anti-TWEAK antibody prevented proliferation induced by 100 ng/ml TWEAK at 18 hrs, as assessed by BrdU incorporation. Mean (±S.E.M.) of four independent experiments. *P < 0.005 versus control; #P < 0.003 versus TWEAK alone. (E) TWEAK-induced proliferation in human HK2 tubular cells as assessed by BrdU incorporation dose–response at 18 hrs, *P < 0.02 versus 0% FBS. **P < 0.001 versus 0% FBS. Mean (±S.E.M.) of four independent experiments. Cells cultured in 5% FBS medium were used as positive controls.
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fig01: TWEAK increases cell proliferation in cultured murine (A–D) and human (E) renal tubular cells. (A) and (B) Quantification by flow cytometry of tubular cell number following treatment with TWEAK: (A) Time–response to 100 ng/ml TWEAK in serum-deprived cells, **P < 0.005 versus its corresponding control; *P < 0.05 versus control. Mean (±S.E.M.) of four independent experiments. (B) Dose–response at 18 hrs, *P < 0.02 versus 0% FBS. Mean (±S.E.M.) of four independent experiments. Cells cultured in 5% FBS medium were used as positive controls. (C) Treatment with 100 ng/ml TWEAK for 18 hrs induced cell proliferation (flow cytometry of DNA content). Note the increased proportion of cells in the S and M phase of the cell cycle (/––––/), without changes in the apoptotic rate (arrow). Mean (±S.E.M.) of four experiments, *P < 0.002 versus control. (D) ITEM-4, a neutralizing anti-Fn14 antibody and an anti-TWEAK antibody prevented proliferation induced by 100 ng/ml TWEAK at 18 hrs, as assessed by BrdU incorporation. Mean (±S.E.M.) of four independent experiments. *P < 0.005 versus control; #P < 0.003 versus TWEAK alone. (E) TWEAK-induced proliferation in human HK2 tubular cells as assessed by BrdU incorporation dose–response at 18 hrs, *P < 0.02 versus 0% FBS. **P < 0.001 versus 0% FBS. Mean (±S.E.M.) of four independent experiments. Cells cultured in 5% FBS medium were used as positive controls.

Mentions: Human proximal tubular epithelial (HK-2) cells (ATCC, Rockville, MD, USA) were grown on the same media as the MCT cells plus 5 μg/ml insulin, 5 μg/ml transferrin, 5 ng/ml sodium selenite, and 5 ng/ml hydrocortisone [15]. Results for these cells are only shown in Fig. 1E.


Tweak induces proliferation in renal tubular epithelium: a role in uninephrectomy induced renal hyperplasia.

Sanz AB, Sanchez-Niño MD, Izquierdo MC, Jakubowski A, Justo P, Blanco-Colio LM, Ruiz-Ortega M, Egido J, Ortiz A - J. Cell. Mol. Med. (2009)

TWEAK increases cell proliferation in cultured murine (A–D) and human (E) renal tubular cells. (A) and (B) Quantification by flow cytometry of tubular cell number following treatment with TWEAK: (A) Time–response to 100 ng/ml TWEAK in serum-deprived cells, **P < 0.005 versus its corresponding control; *P < 0.05 versus control. Mean (±S.E.M.) of four independent experiments. (B) Dose–response at 18 hrs, *P < 0.02 versus 0% FBS. Mean (±S.E.M.) of four independent experiments. Cells cultured in 5% FBS medium were used as positive controls. (C) Treatment with 100 ng/ml TWEAK for 18 hrs induced cell proliferation (flow cytometry of DNA content). Note the increased proportion of cells in the S and M phase of the cell cycle (/––––/), without changes in the apoptotic rate (arrow). Mean (±S.E.M.) of four experiments, *P < 0.002 versus control. (D) ITEM-4, a neutralizing anti-Fn14 antibody and an anti-TWEAK antibody prevented proliferation induced by 100 ng/ml TWEAK at 18 hrs, as assessed by BrdU incorporation. Mean (±S.E.M.) of four independent experiments. *P < 0.005 versus control; #P < 0.003 versus TWEAK alone. (E) TWEAK-induced proliferation in human HK2 tubular cells as assessed by BrdU incorporation dose–response at 18 hrs, *P < 0.02 versus 0% FBS. **P < 0.001 versus 0% FBS. Mean (±S.E.M.) of four independent experiments. Cells cultured in 5% FBS medium were used as positive controls.
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Related In: Results  -  Collection

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fig01: TWEAK increases cell proliferation in cultured murine (A–D) and human (E) renal tubular cells. (A) and (B) Quantification by flow cytometry of tubular cell number following treatment with TWEAK: (A) Time–response to 100 ng/ml TWEAK in serum-deprived cells, **P < 0.005 versus its corresponding control; *P < 0.05 versus control. Mean (±S.E.M.) of four independent experiments. (B) Dose–response at 18 hrs, *P < 0.02 versus 0% FBS. Mean (±S.E.M.) of four independent experiments. Cells cultured in 5% FBS medium were used as positive controls. (C) Treatment with 100 ng/ml TWEAK for 18 hrs induced cell proliferation (flow cytometry of DNA content). Note the increased proportion of cells in the S and M phase of the cell cycle (/––––/), without changes in the apoptotic rate (arrow). Mean (±S.E.M.) of four experiments, *P < 0.002 versus control. (D) ITEM-4, a neutralizing anti-Fn14 antibody and an anti-TWEAK antibody prevented proliferation induced by 100 ng/ml TWEAK at 18 hrs, as assessed by BrdU incorporation. Mean (±S.E.M.) of four independent experiments. *P < 0.005 versus control; #P < 0.003 versus TWEAK alone. (E) TWEAK-induced proliferation in human HK2 tubular cells as assessed by BrdU incorporation dose–response at 18 hrs, *P < 0.02 versus 0% FBS. **P < 0.001 versus 0% FBS. Mean (±S.E.M.) of four independent experiments. Cells cultured in 5% FBS medium were used as positive controls.
Mentions: Human proximal tubular epithelial (HK-2) cells (ATCC, Rockville, MD, USA) were grown on the same media as the MCT cells plus 5 μg/ml insulin, 5 μg/ml transferrin, 5 ng/ml sodium selenite, and 5 ng/ml hydrocortisone [15]. Results for these cells are only shown in Fig. 1E.

Bottom Line: In this regard, TWEAK knock-out mice with AKI displayed less tubular apoptosis and proliferation, as well as improved renal function.In conclusion, TWEAK actions in tubular cells are context dependent.This may be relevant for compensatory renal hyperplasia following nephrectomy.

View Article: PubMed Central - PubMed

Affiliation: Fundación Jiménez Díaz, Universidad Autónoma de Madrid, Fundación Renal Iñigo Alvarez de Toledo, Madrid, Spain.

ABSTRACT
The tumour necrosis factor (TNF) family member TWEAK activates the Fn14 receptor and has pro-apoptotic, proliferative and pro-inflammatory actions that depend on the cell type and the microenvironment. We explored the proliferative actions of TWEAK on cultured tubular cells and in vivo on renal tubules. Additionally, we studied the role of TWEAK in compensatory proliferation following unilateral nephrectomy and in an inflammatory model of acute kidney injury (AKI) induced by a folic acid overdose. TWEAK increased the proliferation, cell number and cyclin D1 expression of cultured tubular cells, in vitro. Exposure to serum increased TWEAK and Fn14 expression and the proliferative response to TWEAK. TWEAK activated the mitogen-activated protein kinases ERK and p38, the phosphatidyl-inositol 3-kinase (PI3K)/Akt pathway and NF-kappaB. TWEAK-induced proliferation was prevented by inhibitors of these protein kinases and by the NF-kappaB inhibitor parthenolide. TWEAK-induced tubular cell proliferation as assessed by PCNA and cyclin D1 expression in the kidneys of adult healthy mice in vivo. By contrast, TWEAK knock-out mice displayed lower tubular cell proliferation in the remnant kidney following unilateral nephrectomy, a non-inflammatory model. This is consistent with TWEAK-induced proliferation on cultured tubular cells in the absence of inflammatory cytokines. Consistent with our previously published data, in the presence of inflammatory cytokines TWEAK promoted apoptosis, not proliferation, of cultured tubular cells. In this regard, TWEAK knock-out mice with AKI displayed less tubular apoptosis and proliferation, as well as improved renal function. In conclusion, TWEAK actions in tubular cells are context dependent. In a non-inflammatory milieu TWEAK induces proliferation of tubular epithelium. This may be relevant for compensatory renal hyperplasia following nephrectomy.

Show MeSH
Related in: MedlinePlus