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Axl Expression in Renal Mesangial Cells Is Regulated by Sp1, Ap1, MZF1, and Ep300, and the IL-6/miR-34a Pathway

Axl receptor tyrosine kinase expression in the kidney contributes to a variety of inflammatory renal disease by promoting glomerular proliferation. Axl expression in the kidney is negligible in healthy individuals but upregulated under inflammatory conditions. Little is known about Axl transcription...

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Autores principales: Adams, David E., Zhen, Yuxuan, Qi, Xiaoyang, Shao, Wen-Hai
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9221537/
https://www.ncbi.nlm.nih.gov/pubmed/35740998
http://dx.doi.org/10.3390/cells11121869
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author Adams, David E.
Zhen, Yuxuan
Qi, Xiaoyang
Shao, Wen-Hai
author_facet Adams, David E.
Zhen, Yuxuan
Qi, Xiaoyang
Shao, Wen-Hai
author_sort Adams, David E.
collection PubMed
description Axl receptor tyrosine kinase expression in the kidney contributes to a variety of inflammatory renal disease by promoting glomerular proliferation. Axl expression in the kidney is negligible in healthy individuals but upregulated under inflammatory conditions. Little is known about Axl transcriptional regulation. We analyzed the 4.4 kb mouse Axl promoter region and found that many transcription factor (TF)-binding sites and regulatory elements are located within a 600 bp fragment proximal to the translation start site. Among four TFs (Sp1, Ap1, MZF1, and Ep300) identified, Sp1 was the most potent TF that promotes Axl expression. Luciferase assays confirmed the siRNA results and revealed additional mechanisms that regulate Axl expression, including sequences encoding a 5′-UTR mini-intron and potential G-quadruplex forming regions. Deletion of the Axl 5′-UTR mini-intron resulted in a 3.2-fold increases in luciferase activity over the full-length UTR (4.4 kb Axl construct). The addition of TMPyP4, a G-quadruplex stabilizer, resulted in a significantly decreased luciferase activity. Further analysis of the mouse Axl 3′-UTR revealed a miRNA-34a binding site, which inversely regulates Axl expression. The inhibitory role of miRNA-34a in Axl expression was demonstrated in mesangial cells using miRNA-34a mimicry and in primary kidney cells with IL-6 stimulated STAT3 activation. Taken together, Axl expression in mouse kidney is synergistically regulated by multiple factors, including TFs and secondary structures, such as mini-intron and G-quadruplex. A unique IL6/STAT3/miRNA-34a pathway was revealed to be critical in inflammatory renal Axl expression.
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spelling pubmed-92215372022-06-24 Axl Expression in Renal Mesangial Cells Is Regulated by Sp1, Ap1, MZF1, and Ep300, and the IL-6/miR-34a Pathway Adams, David E. Zhen, Yuxuan Qi, Xiaoyang Shao, Wen-Hai Cells Article Axl receptor tyrosine kinase expression in the kidney contributes to a variety of inflammatory renal disease by promoting glomerular proliferation. Axl expression in the kidney is negligible in healthy individuals but upregulated under inflammatory conditions. Little is known about Axl transcriptional regulation. We analyzed the 4.4 kb mouse Axl promoter region and found that many transcription factor (TF)-binding sites and regulatory elements are located within a 600 bp fragment proximal to the translation start site. Among four TFs (Sp1, Ap1, MZF1, and Ep300) identified, Sp1 was the most potent TF that promotes Axl expression. Luciferase assays confirmed the siRNA results and revealed additional mechanisms that regulate Axl expression, including sequences encoding a 5′-UTR mini-intron and potential G-quadruplex forming regions. Deletion of the Axl 5′-UTR mini-intron resulted in a 3.2-fold increases in luciferase activity over the full-length UTR (4.4 kb Axl construct). The addition of TMPyP4, a G-quadruplex stabilizer, resulted in a significantly decreased luciferase activity. Further analysis of the mouse Axl 3′-UTR revealed a miRNA-34a binding site, which inversely regulates Axl expression. The inhibitory role of miRNA-34a in Axl expression was demonstrated in mesangial cells using miRNA-34a mimicry and in primary kidney cells with IL-6 stimulated STAT3 activation. Taken together, Axl expression in mouse kidney is synergistically regulated by multiple factors, including TFs and secondary structures, such as mini-intron and G-quadruplex. A unique IL6/STAT3/miRNA-34a pathway was revealed to be critical in inflammatory renal Axl expression. MDPI 2022-06-09 /pmc/articles/PMC9221537/ /pubmed/35740998 http://dx.doi.org/10.3390/cells11121869 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Adams, David E.
Zhen, Yuxuan
Qi, Xiaoyang
Shao, Wen-Hai
Axl Expression in Renal Mesangial Cells Is Regulated by Sp1, Ap1, MZF1, and Ep300, and the IL-6/miR-34a Pathway
title Axl Expression in Renal Mesangial Cells Is Regulated by Sp1, Ap1, MZF1, and Ep300, and the IL-6/miR-34a Pathway
title_full Axl Expression in Renal Mesangial Cells Is Regulated by Sp1, Ap1, MZF1, and Ep300, and the IL-6/miR-34a Pathway
title_fullStr Axl Expression in Renal Mesangial Cells Is Regulated by Sp1, Ap1, MZF1, and Ep300, and the IL-6/miR-34a Pathway
title_full_unstemmed Axl Expression in Renal Mesangial Cells Is Regulated by Sp1, Ap1, MZF1, and Ep300, and the IL-6/miR-34a Pathway
title_short Axl Expression in Renal Mesangial Cells Is Regulated by Sp1, Ap1, MZF1, and Ep300, and the IL-6/miR-34a Pathway
title_sort axl expression in renal mesangial cells is regulated by sp1, ap1, mzf1, and ep300, and the il-6/mir-34a pathway
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9221537/
https://www.ncbi.nlm.nih.gov/pubmed/35740998
http://dx.doi.org/10.3390/cells11121869
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