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Distribution of GBM heparan sulfate proteoglycan core protein and side chains in human glomerular diseases
J van den Born1, L P van den Heuvel, M A Bakker
1Department of Medicine, University of Nijmegen, The Netherlands.
Insights
Researchers studied kidney tissue from 95 patients with various glomerulopathies. They found significant changes in heparan sulfate (HS) and heparan sulfate proteoglycan (HSPG) distribution in diseased kidneys, suggesting these molecules play a role in kidney disease progression.
Area of Science:
- Nephrology
- Molecular Biology
- Immunohistochemistry
Background:
- Heparan sulfate proteoglycans (HSPG) are crucial components of the glomerular basement membrane (GBM).
- Alterations in GBM composition are implicated in the pathogenesis of various glomerulopathies.
Purpose of the Study:
- To investigate the glomerular distribution of HSPG core protein and heparan sulfate (HS) side chains in normal and diseased human kidney tissues.
- To assess the utility of monoclonal antibodies (mAbs) against HSPG core and HS in diagnosing and understanding glomerulopathies.
Main Methods:
- Utilized monoclonal antibodies (mAbs) targeting HSPG core protein (JM-72) and HS side chains (JM-403).
- Examined 95 human kidney biopsies across twelve glomerulopathies and four normal controls using cryostat sections.
- Analyzed staining patterns in the GBM, mesangial matrix, and amyloid deposits.
Main Results:
- Normal kidneys showed homogenous GBM staining for both HSPG core and HS.
- Segmental or absent GBM staining for HS was observed in lupus nephritis, membranous GN, minimal change disease, and diabetic nephropathy.
- HSPG core protein was found in the mesangial matrix in several proliferative and sclerotic glomerulopathies.
- Amyloid deposits stained positively for HSPG core and, to a lesser extent, HS.
- Irregular GBM staining for HSPG core was noted in membranous GN stages II and III.
Conclusions:
- Significant alterations in the glomerular distribution of HS and HSPG core protein occur in various human glomerulopathies.
- These findings highlight the potential of mAbs against HSPG and HS as diagnostic and prognostic tools in kidney disease.
- The study underscores the importance of HSPG and HS in maintaining glomerular structure and function.
Abstract:
Using monoclonal antibodies (mAbs) recognizing either the core protein or the heparan sulfate (HS) side chain of human GBM heparan sulfate proteoglycan (HSPG), we investigated their glomerular distribution on cryostat sections of human kidney tissues. The study involved 95 biopsies comprising twelve different glomerulopathies. Four normal kidney specimens served as controls. A homogenous to linear staining of the GBM was observed in the normal kidney with anti-HSPG-core mAb (JM-72) and anti-HS mAb (JM-403). In human glomerulopathies the major alteration was a segmental or total absence of GBM staining with anti-HS mAb JM-403, which is most pronounced in lupus nephritis, membranous glomerulonephritis (GN), minimal change disease and diabetic nephropathy, whereas the HSPG-core staining by mAb JM-72 was unaltered. In addition we found HSPG-core protein in the mesangial matrix when this was increased in membranoproliferative GN Type I, Schönlein-Henoch GN, IgA nephropathy, lupus nephritis, diabetic nephropathy and in focal glomerulosclerosis. Also staining with the anti-HS mAb JM-403 became positive within the mesangium, although to a lesser extent. Furthermore, amyloid deposits in AL and AA amyloidosis clearly stained with anti-HSPG-core mAb JM-72, and to a lesser degree with anti-HS mAb JM-403. Finally, in membranous GN (stage II and III), the GBM staining with anti-HSPG-core mAb JM-72 became irregular or granular, probably related to the formation of spikes. In conclusion, major alterations were observed in the glomerular distribution of HS and HSPG-core in various human glomerulopathies. The mAbs can be useful to further delineate the significance of HSPG and HS for glomerular diseases.