Abstract
Tubular epithelial cells take up and degrade plasma albumin filtered by the glomerulus. Tubular damage resulting in reduced albumin uptake or degradation has been suggested as one mechanism contributing to albuminuria in kidney disease. This study investigated whether tubular albumin uptake or degradation is altered in acute and chronic glomerular disease. Mouse models of acute glomerular injury (anti-GBM disease and LPS-induced albuminuria) and chronic disease (streptozotocin-induced diabetes and db/db mice) were examined. Mice were injected intravenously with Alexa-albumin plus DQ-albumin and killed 20 minutes later. Tubular uptake of albumin (Alexa-albumin) and albumin degradation (Dye Quenched (DQ)-albumin) was assessed in tissue sections via confocal microscopy. Tubular uptake of Alexa-albumin in the models of diabetic nephropathy was not different to normal mice. However, the fluorescence signal resulting from degradation of DQ-albumin was significantly reduced in db/db mice, and the ratio of degraded to intact albumin was reduced in both models. The ratio of degraded to intact albumin in tubules was also reduced in the anti-GBM model. In the LPS model, both tubular uptake and degradation of albumin were significantly reduced, with a substantial reduction in the ratio of degraded to intact albumin in tubules. LPS stimulation of cultured tubular epithelial cells inhibited albumin uptake, indicating a direct role for LPS in modifying tubular handling of albumin. In conclusion, reduced degradation of filtered albumin in the proximal tubule is a common feature of glomerular diseases. This may be a general mechanism whereby tubular dysfunction contributes to the development of albuminuria.
| Original language | English |
|---|---|
| Pages (from-to) | 241-249 |
| Number of pages | 9 |
| Journal | Clinical and Experimental Pharmacology and Physiology |
| Volume | 45 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - 1 Mar 2018 |
Keywords
- albuminuria
- anti-GBM disease
- diabetic nephropathy
- LPS
Cite this
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Reduced tubular degradation of glomerular filtered plasma albumin is a common feature in acute and chronic kidney disease. / Han, Yingjie; Ly, Nguyen D K; Tesch, Greg H; Poronnik, Philip; Nikolic-Paterson, David J.
In: Clinical and Experimental Pharmacology and Physiology, Vol. 45, No. 3, 01.03.2018, p. 241-249.Research output: Contribution to journal › Article › Research › peer-review
TY - JOUR
T1 - Reduced tubular degradation of glomerular filtered plasma albumin is a common feature in acute and chronic kidney disease
AU - Han, Yingjie
AU - Ly, Nguyen D K
AU - Tesch, Greg H
AU - Poronnik, Philip
AU - Nikolic-Paterson, David J
PY - 2018/3/1
Y1 - 2018/3/1
N2 - Tubular epithelial cells take up and degrade plasma albumin filtered by the glomerulus. Tubular damage resulting in reduced albumin uptake or degradation has been suggested as one mechanism contributing to albuminuria in kidney disease. This study investigated whether tubular albumin uptake or degradation is altered in acute and chronic glomerular disease. Mouse models of acute glomerular injury (anti-GBM disease and LPS-induced albuminuria) and chronic disease (streptozotocin-induced diabetes and db/db mice) were examined. Mice were injected intravenously with Alexa-albumin plus DQ-albumin and killed 20 minutes later. Tubular uptake of albumin (Alexa-albumin) and albumin degradation (Dye Quenched (DQ)-albumin) was assessed in tissue sections via confocal microscopy. Tubular uptake of Alexa-albumin in the models of diabetic nephropathy was not different to normal mice. However, the fluorescence signal resulting from degradation of DQ-albumin was significantly reduced in db/db mice, and the ratio of degraded to intact albumin was reduced in both models. The ratio of degraded to intact albumin in tubules was also reduced in the anti-GBM model. In the LPS model, both tubular uptake and degradation of albumin were significantly reduced, with a substantial reduction in the ratio of degraded to intact albumin in tubules. LPS stimulation of cultured tubular epithelial cells inhibited albumin uptake, indicating a direct role for LPS in modifying tubular handling of albumin. In conclusion, reduced degradation of filtered albumin in the proximal tubule is a common feature of glomerular diseases. This may be a general mechanism whereby tubular dysfunction contributes to the development of albuminuria.
AB - Tubular epithelial cells take up and degrade plasma albumin filtered by the glomerulus. Tubular damage resulting in reduced albumin uptake or degradation has been suggested as one mechanism contributing to albuminuria in kidney disease. This study investigated whether tubular albumin uptake or degradation is altered in acute and chronic glomerular disease. Mouse models of acute glomerular injury (anti-GBM disease and LPS-induced albuminuria) and chronic disease (streptozotocin-induced diabetes and db/db mice) were examined. Mice were injected intravenously with Alexa-albumin plus DQ-albumin and killed 20 minutes later. Tubular uptake of albumin (Alexa-albumin) and albumin degradation (Dye Quenched (DQ)-albumin) was assessed in tissue sections via confocal microscopy. Tubular uptake of Alexa-albumin in the models of diabetic nephropathy was not different to normal mice. However, the fluorescence signal resulting from degradation of DQ-albumin was significantly reduced in db/db mice, and the ratio of degraded to intact albumin was reduced in both models. The ratio of degraded to intact albumin in tubules was also reduced in the anti-GBM model. In the LPS model, both tubular uptake and degradation of albumin were significantly reduced, with a substantial reduction in the ratio of degraded to intact albumin in tubules. LPS stimulation of cultured tubular epithelial cells inhibited albumin uptake, indicating a direct role for LPS in modifying tubular handling of albumin. In conclusion, reduced degradation of filtered albumin in the proximal tubule is a common feature of glomerular diseases. This may be a general mechanism whereby tubular dysfunction contributes to the development of albuminuria.
KW - albuminuria
KW - anti-GBM disease
KW - diabetic nephropathy
KW - LPS
UR - http://www.scopus.com/inward/record.url?scp=85035220152&partnerID=8YFLogxK
U2 - 10.1111/1440-1681.12878
DO - 10.1111/1440-1681.12878
M3 - Article
VL - 45
SP - 241
EP - 249
JO - Clinical and Experimental Pharmacology and Physiology
JF - Clinical and Experimental Pharmacology and Physiology
SN - 0305-1870
IS - 3
ER -