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Neph1 is reduced in primary focal segmental glomerulosclerosis, minimal change nephrotic syndrome, and corresponding experimental animal models of adriamycin-induced nephropathy and puromycin aminonucleoside nephrosis.

Hulkko J, Patrakka J, Lal M, Tryggvason K, Hultenby K, Wernerson A - Nephron Extra (2014)

Bottom Line: We localized Neph1 mainly to, and in close proximity to, the SD.Double staining of Neph1 and nephrin showed the proteins to be in close connection in the SD.The reduction of Neph1 was also seen in areas with and without FPE.

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical Science, Intervention and Technology, Stockholm, Sweden.

ABSTRACT

Background/aims: The transmembrane proteins Neph1 and nephrin form a complex in the slit diaphragm (SD) of podocytes. As recent studies indicate an involvement of this complex in the polymerization of the actin cytoskeleton and proteinuria, we wanted to study the subcellular localization of Neph1 in the normal human kidney and its expression in focal segmental glomerulosclerosis (FSGS), minimal change nephrotic syndrome (MCNS), and the corresponding experimental models of Adriamycin-induced nephropathy (ADR) and puromycin aminonucleoside nephrosis (PAN). All these disorders are characterized by substantial foot process effacement (FPE) and proteinuria.

Materials and methods: Kidney biopsies from patients with primary FSGS (perihilar type) and MCNS were compared to normal renal tissue. Mouse and rat kidney cortices from days 7 and 14 after Adriamycin injection and days 2 and 4 after puromycin aminonucleoside injection, respectively, were compared to control mouse and rat kidney. Polyclonal antibodies against Neph1 and nephrin were used for immunoelectron microscopy, and semiquantification was performed.

Results: We localized Neph1 mainly to, and in close proximity to, the SD. Double staining of Neph1 and nephrin showed the proteins to be in close connection in the SD. The total amount of Neph1 in the podocytes was significantly reduced in FSGS, MCNS, ADR, and PAN. The reduction of Neph1 was also seen in areas with and without FPE. Nephrin was reduced in MCNS and PAN but unchanged in FSGS.

Conclusion: With nephrin (but not Neph1) unchanged in FSGS, there might be a disruption of the complex and an involvement of Neph1 in its pathogenesis.

No MeSH data available.


Related in: MedlinePlus

iEM of human biopsies. Immunogold labeling of Neph1 (arrowheads) in kidney. a Neph1 in normal human kidney, localized to the foot processes close to the SD. b Double labeling of Neph1 (10 nm; arrow) and nephrin (5 nm; arrowheads) in the foot process in normal human kidney. c, d Labeling of Neph1 in FSGS (c) and MCNS (d). P = Podocyte; E = endothelial cell. Scale bars = 300 nm (a, c, d) and 100 nm (b).
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Figure 1: iEM of human biopsies. Immunogold labeling of Neph1 (arrowheads) in kidney. a Neph1 in normal human kidney, localized to the foot processes close to the SD. b Double labeling of Neph1 (10 nm; arrow) and nephrin (5 nm; arrowheads) in the foot process in normal human kidney. c, d Labeling of Neph1 in FSGS (c) and MCNS (d). P = Podocyte; E = endothelial cell. Scale bars = 300 nm (a, c, d) and 100 nm (b).

Mentions: We localized Neph1 mainly to, and in close proximity to, the SD and to the podocyte cytoplasm (fig. 1a). Expression was also observed in the glomerular endothelium (0.5 ± 0.3 Au/μm2) but only negligible amounts in the GBM (0.1 ± 0.0 Au/μm2). There was no change in the amount of Neph1 in the endothelium of diseased tissue (data not shown) compared to that of controls. Double staining of Neph1 and nephrin in normal human kidney showed the proteins in close connection in the SD (fig. 1b).


Neph1 is reduced in primary focal segmental glomerulosclerosis, minimal change nephrotic syndrome, and corresponding experimental animal models of adriamycin-induced nephropathy and puromycin aminonucleoside nephrosis.

Hulkko J, Patrakka J, Lal M, Tryggvason K, Hultenby K, Wernerson A - Nephron Extra (2014)

iEM of human biopsies. Immunogold labeling of Neph1 (arrowheads) in kidney. a Neph1 in normal human kidney, localized to the foot processes close to the SD. b Double labeling of Neph1 (10 nm; arrow) and nephrin (5 nm; arrowheads) in the foot process in normal human kidney. c, d Labeling of Neph1 in FSGS (c) and MCNS (d). P = Podocyte; E = endothelial cell. Scale bars = 300 nm (a, c, d) and 100 nm (b).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4202611&req=5

Figure 1: iEM of human biopsies. Immunogold labeling of Neph1 (arrowheads) in kidney. a Neph1 in normal human kidney, localized to the foot processes close to the SD. b Double labeling of Neph1 (10 nm; arrow) and nephrin (5 nm; arrowheads) in the foot process in normal human kidney. c, d Labeling of Neph1 in FSGS (c) and MCNS (d). P = Podocyte; E = endothelial cell. Scale bars = 300 nm (a, c, d) and 100 nm (b).
Mentions: We localized Neph1 mainly to, and in close proximity to, the SD and to the podocyte cytoplasm (fig. 1a). Expression was also observed in the glomerular endothelium (0.5 ± 0.3 Au/μm2) but only negligible amounts in the GBM (0.1 ± 0.0 Au/μm2). There was no change in the amount of Neph1 in the endothelium of diseased tissue (data not shown) compared to that of controls. Double staining of Neph1 and nephrin in normal human kidney showed the proteins in close connection in the SD (fig. 1b).

Bottom Line: We localized Neph1 mainly to, and in close proximity to, the SD.Double staining of Neph1 and nephrin showed the proteins to be in close connection in the SD.The reduction of Neph1 was also seen in areas with and without FPE.

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical Science, Intervention and Technology, Stockholm, Sweden.

ABSTRACT

Background/aims: The transmembrane proteins Neph1 and nephrin form a complex in the slit diaphragm (SD) of podocytes. As recent studies indicate an involvement of this complex in the polymerization of the actin cytoskeleton and proteinuria, we wanted to study the subcellular localization of Neph1 in the normal human kidney and its expression in focal segmental glomerulosclerosis (FSGS), minimal change nephrotic syndrome (MCNS), and the corresponding experimental models of Adriamycin-induced nephropathy (ADR) and puromycin aminonucleoside nephrosis (PAN). All these disorders are characterized by substantial foot process effacement (FPE) and proteinuria.

Materials and methods: Kidney biopsies from patients with primary FSGS (perihilar type) and MCNS were compared to normal renal tissue. Mouse and rat kidney cortices from days 7 and 14 after Adriamycin injection and days 2 and 4 after puromycin aminonucleoside injection, respectively, were compared to control mouse and rat kidney. Polyclonal antibodies against Neph1 and nephrin were used for immunoelectron microscopy, and semiquantification was performed.

Results: We localized Neph1 mainly to, and in close proximity to, the SD. Double staining of Neph1 and nephrin showed the proteins to be in close connection in the SD. The total amount of Neph1 in the podocytes was significantly reduced in FSGS, MCNS, ADR, and PAN. The reduction of Neph1 was also seen in areas with and without FPE. Nephrin was reduced in MCNS and PAN but unchanged in FSGS.

Conclusion: With nephrin (but not Neph1) unchanged in FSGS, there might be a disruption of the complex and an involvement of Neph1 in its pathogenesis.

No MeSH data available.


Related in: MedlinePlus