Abstract
Nerve growth factor is a neurotrophin that promotes cell growth, differentiation, survival and death through two different receptors: TrkA(NTR) and p75(NTR). Nerve growth factor serum concentrations increase during many inflammatory and autoimmune diseases, glomerulonephritis, chronic kidney disease, end-stage renal disease and, particularly, in renal transplant. Considering that nerve growth factor exerts beneficial effects in the treatment of major central and peripheral neurodegenerative diseases, skin and corneal ulcers, we asked whether nerve growth factor could also exert a role in Cyclosporine A-induced graft nephrotoxicity. Our hypothesis was raised from basic evidence indicating that Cyclosporine A-inhibition of calcineurin-NFAT pathway increases nerve growth factor expression levels. Therefore, we investigated the involvement of nerve growth factor and its receptors in the damage exerted by Cyclosporine A in tubular renal cells, HK-2. Our results showed that in HK-2 cells combined treatment with Cyclosporine A + nerve growth factor induced a significant reduction in cell vitality concomitant with a down-regulation of Cyclin D1 and up-regulation of p21 levels respect to cells treated with Cyclosporine A alone. Moreover functional experiments showed that the co-treatment significantly up-regulated human p21promoter activity by involvement of the Sp1 transcription factor, whose nuclear content was negatively regulated by activated NFATc1. In addition we observed that the combined exposure to Cyclosporine A + nerve growth factor promoted an up-regulation of p75 (NTR) and its target genes, p53 and BAD leading to the activation of intrinsic apoptosis. Finally, the chemical inhibition of p75(NTR) down-regulated the intrinsic apoptotic signal. We describe two new mechanisms by which nerve growth factor promotes growth arrest and apoptosis in tubular renal cells exposed to Cyclosporine A.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Apoptosis / drug effects*
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Cell Line
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Cell Survival / drug effects
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Cyclin D1 / antagonists & inhibitors
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Cyclin D1 / genetics
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Cyclin D1 / metabolism
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Cyclosporine / pharmacology*
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Drug Synergism
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Enzyme Inhibitors / pharmacology*
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Epithelial Cells / cytology
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Epithelial Cells / drug effects*
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Epithelial Cells / metabolism
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Gene Expression Regulation
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Humans
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Kidney Tubules, Proximal / cytology
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Kidney Tubules, Proximal / drug effects*
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Kidney Tubules, Proximal / metabolism
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NFATC Transcription Factors / agonists
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NFATC Transcription Factors / genetics
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NFATC Transcription Factors / metabolism
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Nerve Growth Factor / pharmacology*
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Nerve Tissue Proteins / agonists
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Nerve Tissue Proteins / genetics
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Nerve Tissue Proteins / metabolism
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Promoter Regions, Genetic
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Receptors, Nerve Growth Factor / agonists
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Receptors, Nerve Growth Factor / genetics
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Receptors, Nerve Growth Factor / metabolism
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Signal Transduction
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Sp1 Transcription Factor / antagonists & inhibitors
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Sp1 Transcription Factor / genetics
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Sp1 Transcription Factor / metabolism
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Tumor Suppressor Protein p53 / agonists
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Tumor Suppressor Protein p53 / genetics
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Tumor Suppressor Protein p53 / metabolism
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bcl-Associated Death Protein / agonists
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bcl-Associated Death Protein / genetics
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bcl-Associated Death Protein / metabolism
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p21-Activated Kinases / genetics
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p21-Activated Kinases / metabolism
Substances
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BAD protein, human
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Enzyme Inhibitors
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NFATC Transcription Factors
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NFATC1 protein, human
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NGF protein, human
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NGFR protein, human
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Nerve Tissue Proteins
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Receptors, Nerve Growth Factor
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Sp1 Transcription Factor
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Tumor Suppressor Protein p53
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bcl-Associated Death Protein
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Cyclin D1
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Cyclosporine
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Nerve Growth Factor
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p21-Activated Kinases
Grants and funding
The study was supported by "Associazione Sud Italia Trapiantati":
http://www.asitonline.it/. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.