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Updated: Jul 6, 2026
Detection of MicroRNA Expression in the Kidneys of Immunoglobulin A Nephropathic Mice
Published on: July 8, 2020
Downregulated expression in high IgA (HIGA) mice and the renal protective role of meprinbeta
Hiromitsu Yoshimura1, Masayoshi Ito, Yusuke Kuwahara
1Molecular Function and Pharmacology Laboratories, Taisho Pharmaceutical Co., Ltd, Saitama, 331-9530, Japan. hi.yoshimura@po.rd.taisho.co.jp
Abstract:
This study discusses the critical role of the metalloproteinase meprinbeta in the progression of glomerulonephritis. Using a microarray technique, the gene expression profiles in glomeruli isolated from high serum IgA (HIGA) mice with a purity of 97% or greater were examined. HIGA mice are a valid model of human IgA nephropathy (IgAN), with the typical pathological features of this condition, including a consistently high serum IgA level as well as dominant mesangial IgA deposition and mesangial enlargement. Among the many upregulated/downregulated genes after the development of IgAN, the downregulation of meprinbeta was intriguing. The expression level of the meprinbeta gene at 40 weeks of age was 52% of that observed at 8 weeks of age (prior to the development of IgAN), although in the control BALB/c mice, a 2.19-fold elevation was seen. These results were also confirmed by semi-quantitative RT-PCR and immunostaining analyses. As meprinbeta is a subunit of metalloproteinase meprins (meprin A, meprin B) and meprins are capable of proteolytically degrading extracellular matrix (ECM) components and proteolytically processing bioactive peptides, the downregulation of meprinbeta may contribute to the progression of glomerulonephritis and the eventual glomerular scarring. This working hypothesis was examined using an in vivo meprinbeta inhibition study. The inhibition of meprins by actinonin exacerbated some parameters of renal injury in mice afflicted with anti-glomerular basement membrane (anti-GBM) antibody-associated nephritis. These in vitro and in vivo results suggest that meprinbeta may play a protective role against the progression of renal injury through the degradation of ECM and bioactive peptides.
Insights
Meprinbeta, a metalloproteinase, plays a protective role in kidney disease. Its downregulation in IgA nephropathy suggests it may prevent glomerular scarring by degrading extracellular matrix and bioactive peptides.
Area of Science:
- Nephrology
- Molecular Biology
- Biochemistry
Background:
- Glomerulonephritis, particularly IgA nephropathy (IgAN), is a significant cause of kidney disease.
- High serum IgA levels and mesangial expansion are hallmarks of IgAN.
- The role of specific metalloproteinases in IgAN progression is not fully understood.
Purpose of the Study:
- To investigate the role of metalloproteinase meprinbeta in the progression of glomerulonephritis.
- To examine gene expression profiles in a mouse model of IgA nephropathy.
- To determine if meprinbeta downregulation contributes to kidney damage.
Main Methods:
- Gene expression profiling using microarray in glomeruli from high serum IgA (HIGA) mice.
- Validation of gene expression changes using semi-quantitative RT-PCR and immunostaining.
- In vivo inhibition of meprins using actinonin in an anti-GBM nephritis model.
Main Results:
- Meprinbeta gene expression was significantly downregulated in HIGA mice with established IgAN compared to younger mice.
- Control mice showed an elevation in meprinbeta expression, contrasting with the downregulation in the disease model.
- Inhibition of meprins exacerbated renal injury in a mouse model of nephritis, suggesting a protective role for meprinbeta.
Conclusions:
- Meprinbeta downregulation may contribute to glomerulonephritis progression and glomerular scarring.
- Meprinbeta likely plays a protective role in renal injury by degrading extracellular matrix and bioactive peptides.
- Targeting meprinbeta could be a potential therapeutic strategy for kidney diseases.
