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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 mouse (a, b) and rat (c, d) biopsies. Immunogold labeling of Neph1 (arrowheads) in kidney. a Neph1 in normal mouse kidney, localized to the foot processes close to the SD. b Neph1 is reduced in ADR on day 14 both in areas with and those without FPE. c Neph1 in normal rat kidney, localized mainly to the SD. d Neph1 is reduced in PAN on day 4 both in areas with and those without FPE. P = Podocyte; E = endothelial cell. Scale bars = 200 nm.
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Figure 2: iEM of mouse (a, b) and rat (c, d) biopsies. Immunogold labeling of Neph1 (arrowheads) in kidney. a Neph1 in normal mouse kidney, localized to the foot processes close to the SD. b Neph1 is reduced in ADR on day 14 both in areas with and those without FPE. c Neph1 in normal rat kidney, localized mainly to the SD. d Neph1 is reduced in PAN on day 4 both in areas with and those without FPE. P = Podocyte; E = endothelial cell. Scale bars = 200 nm.

Mentions: Neph1 was significantly reduced in total amount (1.1 ± 0.2 and 0.8 ± 0.1 Au/μm2) both in areas with (1.0 ± 0.2 and 0.6 ± 0.1 Au/μm2) and those without FPE (1.2 ± 0.1 and 0.9 ± 0.1 Au/μm2) in the ADR day 7 and day 14 groups (fig. 2b), respectively, compared to controls (2.7 ± 0.3 Au/μm2; fig. 2a; table 4). Nephrin was unchanged on day 7 but slightly reduced on day 14 (table 5).


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 mouse (a, b) and rat (c, d) biopsies. Immunogold labeling of Neph1 (arrowheads) in kidney. a Neph1 in normal mouse kidney, localized to the foot processes close to the SD. b Neph1 is reduced in ADR on day 14 both in areas with and those without FPE. c Neph1 in normal rat kidney, localized mainly to the SD. d Neph1 is reduced in PAN on day 4 both in areas with and those without FPE. P = Podocyte; E = endothelial cell. Scale bars = 200 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 2: iEM of mouse (a, b) and rat (c, d) biopsies. Immunogold labeling of Neph1 (arrowheads) in kidney. a Neph1 in normal mouse kidney, localized to the foot processes close to the SD. b Neph1 is reduced in ADR on day 14 both in areas with and those without FPE. c Neph1 in normal rat kidney, localized mainly to the SD. d Neph1 is reduced in PAN on day 4 both in areas with and those without FPE. P = Podocyte; E = endothelial cell. Scale bars = 200 nm.
Mentions: Neph1 was significantly reduced in total amount (1.1 ± 0.2 and 0.8 ± 0.1 Au/μm2) both in areas with (1.0 ± 0.2 and 0.6 ± 0.1 Au/μm2) and those without FPE (1.2 ± 0.1 and 0.9 ± 0.1 Au/μm2) in the ADR day 7 and day 14 groups (fig. 2b), respectively, compared to controls (2.7 ± 0.3 Au/μm2; fig. 2a; table 4). Nephrin was unchanged on day 7 but slightly reduced on day 14 (table 5).

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