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Increased mRNA expression of metalloproteinase-9 in peripheral blood monocytes from patients with immunoglobulin A
H Koide1, T Nakamura, I Ebihara
1Division of Nephrology, Department of Medicine, Juntendo University School of Medicine, Koto Hospital, Tokyo, Japan.
Abstract:
We examined metalloproteinase (MMP)-1, -2, -3, and -9 mRNA expression by peripheral blood monocytes from 50 patients with immunoglobulin A (IgA) nephropathy, 20 with membranous nephropathy, 10 with minimal-change nephrotic syndrome, five with focal glomerulosclerosis, 30 with non-IgA proliferative glomerulonephritis, and 40 healthy normal controls who were comparable with regard to age and sex. Monocytes from patients with IgA nephropathy expressed a higher level of MMP-9 mRNA than those from patients with other forms of glomerulonephritis or from healthy controls (MMP-9 to glyceraldehyde-3-phosphate dehydrogenase ratio: IgA nephropathy, 1.68 +/- 0.24; membranous nephropathy, 0.22 +/- 0.08; minimal-change nephrotic syndrome, 0.24 +/- 0.06; focal glomerulosclerosis, 0.32 +/- 0.08; non-IgA proliferative glomerulonephritis, 0.30 +/- 0.12; and healthy controls, 0.16 +/- 0.04). When the biopsy specimens were classified into four grades according to the severity of glomerular and interstitial pathology, highly significant differences were observed among MMP-9 mRNA levels in monocytes from all four groups of patients with IgA nephropathy (grade I, 0.44 +/- 0.09; grade II, 1.06 +/- 0.26; grade III, 2.22 +/- 0.68; grade IV, 2.86 +/- 0.88). In addition, MMP-9 mRNA levels from patients with IgA nephropathy correlated with urinary protein excretion (P < 0.001). However, we detected minimal mRNA expression of MMP-1, -2, and -3 by peripheral blood monocytes from patients with IgA nephropathy or other forms of glomerulonephritis and from normal healthy controls. Our results suggest that increased MMP-9 mRNA expression in circulating monocytes may contribute to the progression of IgA nephropathy.
Insights
Increased matrix metalloproteinase-9 (MMP-9) mRNA in monocytes is linked to immunoglobulin A (IgA) nephropathy progression. This finding suggests MMP-9 may play a role in the disease
Area of Science:
- Nephrology
- Immunology
- Molecular Biology
Background:
- Immunoglobulin A (IgA) nephropathy is a common form of glomerulonephritis.
- The role of matrix metalloproteinases (MMPs) in IgA nephropathy pathogenesis is not fully understood.
Purpose of the Study:
- To investigate the mRNA expression of MMP-1, -2, -3, and -9 in peripheral blood monocytes of patients with various glomerulonephritis types.
- To determine the correlation between MMP-9 expression and disease severity and urinary protein excretion in IgA nephropathy.
Main Methods:
- Quantitative analysis of MMP-1, -2, -3, and -9 mRNA expression in monocytes using RT-PCR.
- Comparison of MMP expression levels between patients with IgA nephropathy, other glomerulonephritis types, and healthy controls.
- Correlation analysis of MMP-9 mRNA levels with histological grading and urinary protein excretion.
Main Results:
- Monocytes from IgA nephropathy patients showed significantly higher MMP-9 mRNA expression compared to other glomerulonephritis groups and healthy controls.
- MMP-9 mRNA levels in IgA nephropathy correlated positively with disease severity (histological grades) and urinary protein excretion.
- Minimal mRNA expression of MMP-1, -2, and -3 was observed across all groups.
Conclusions:
- Elevated MMP-9 mRNA expression in circulating monocytes is a characteristic feature of IgA nephropathy.
- Increased MMP-9 may contribute to the progression of kidney damage in IgA nephropathy.
- MMP-9 warrants further investigation as a potential biomarker or therapeutic target in IgA nephropathy.