OTUB1 Overexpression in Mesangial Cells Is a Novel Regulator in the Pathogenesis of Glomerulonephritis through the Decrease of DCN Level

Yan Zhang,Zhigang Zhang,Zhonghua Zhao,Hongxia Zhang,Weina Jiang,Yan Wang,Tong Jin,Yu Sun,Yanan Song,Huijuan Wu,Ruimin Hu,Xin Mao

doi:10.1371/journal.pone.0029654

Yan Zhang, Zhigang Zhang + Show 10 more

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https://doi.org/10.1371/journal.pone.0029654

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Journal: PloS one	Publication Date: Jan 18, 2012
Citations: 45	License type: CC BY 4.0

Affiliation: Shanghai Medical College of Fudan University

Abstract

BackgroundOTUB1 is a member of OTUs (Ovarian-tumor-domain-containing proteases), a deubiquitinating enzymes family (DUBs), which was shown as a proteasome-associated DUB to be involved in the proteins Ub-dependent degradation. It has been reported that OTUB1 was expressed in kidney tissue. But its concrete cellular location and function in the kidney remain unclear. Decorin (DCN) in mesangial cells (MC) is considered to be a potentially important factor for antagonizing glomerulonephritides, and its degradation is mediated by ubiquitination. The aim of this study is to investigate the role of OTUB1 expression in MC and its relationship with DCN during glomerulonephritis.Methodology/Principal FindingsUsing quantitative RT-PCR and Western blot, we demonstrated that OTUB1 mRNA and protein were constitutively expressed in cultured rat MC and found to be upregulated by the stimulation of IL-1β or ATS. OTUB1 overexpression was detected in the mesangial area of glomeruli in some immunocomplex mediated nephritides such as IgA nephropathy, acute diffuse proliferative glomerulonephritis and lupus nephritis by immunohistochemistry. The immunoprecipitation assay demonstrated that OTUB1 interacted with DCN. The overexpression of OTUB1 enhanced the ubiquitination and degradation of DCN in MC.Conclusion/SignificanceThese data showed the inflammatory injury could up-regulate OTUB1 expression in MC, which might attribute the promoting effect of OTUB1 on glomerulonephritides to the decrease of DCN level.

Highlights

Ovarian-tumor-domain-containing proteases (OTUs) are part of the deubiquitinating enzymes (DUBs) family [1,2]
The expression of OTUB1 in cultured mesangial cells (MC) In cultured MC, OTUB1 mRNA was found with an amplified fragment of 850 bp by using Reverse transcription (RT)-PCR (Figure 1a), and OTUB1 protein expression was confirmed by Western blot with a molecular weight of 36 kD (Figure 1b)
Immunofluorescence detection of OTUB1 was performed with positive fluorescent signals in the cytoplasm and nuclei of MC compared to the corresponding control (Figure 1c)

Summary

Introduction

Ovarian-tumor-domain-containing proteases (OTUs) are part of the deubiquitinating enzymes (DUBs) family [1,2]. They have been implicated to play an important role in mediating the processes of proteins ubiquitination and degradation through ubiquitin-proteasome pathway (UPP). DUBs can hydrolyze isopeptide bonds between ubiquitin and folded proteins, remove the ubiquitin or polyubiquitins from target proteins, and interfere the degradation of substrates in the Ub-dependent pathway [4]. OTUB1 is a member of OTUs (Ovarian-tumor-domain-containing proteases), a deubiquitinating enzymes family (DUBs), which was shown as a proteasome-associated DUB to be involved in the proteins Ub-dependent degradation. It has been reported that OTUB1 was expressed in kidney tissue. The aim of this study is to investigate the role of OTUB1 expression in MC and its relationship with DCN during glomerulonephritis

Objectives

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Conclusion