Details

Autor(en) / Beteiligte

• Weyer, Kathrin
• Storm, Tina
• Shan, Jingdong
• Vainio, Seppo
• Kozyraki, Renata
• Verroust, Pierre J.
• Christensen, Erik I.
• Nielsen, Rikke

Titel

Mouse model of proximal tubule endocytic dysfunction

Ist Teil von

• Nephrology, dialysis, transplantation, 2011-11, Vol.26 (11), p.3446-3451

Ort / Verlag

Oxford: Oxford University Press

Erscheinungsjahr

2011

Quelle

Oxford Journals 2020 Medicine

Beschreibungen/Notizen

• Background. Several studies have indicated the central role of the megalin/cubilin multiligand endocytic receptor complex in protein reabsorption in the kidney proximal tubule. However, the poor viability of the existing megalin-deficient mice precludes further studies and comparison of homogeneous groups of mice. Methods. Megalin- and/or cubilin-deficient mice were generated using a conditional Cre-loxP system, where the Cre gene is driven by the Wnt4 promoter. Kidney tissues from the mice were analysed for megalin and cubilin expression by quantitative reverse transcription-polymerase chain reaction, western blotting and immunohistochemistry. Renal albumin uptake was visualized by immunohistochemistry. Twenty-four-hour urine samples were collected in metabolic cages and analysed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and western blotting. Urinary albumin/creatinine ratios were measured by ELISA and the alkaline picrate method. Results. The Meglox/lox ;Cre+ , Cubnlox/lox ;Cre+ and Meglox/lox , Cubnlox/lox ;Cre+ mice were all viable, fertile and developed normal kidneys. Megalin and/or cubilin expression, assessed by immunohistology and western blotting, was reduced by >89%. Consistent with this observation, the mice excreted megalin and cubilin ligands such as transferrin and albumin in addition to low-molecular weight proteins. We further show that megalin/cubilin double-deficient mice excrete albumin with an average of 1.45 ± 0.54 mg/day, suggesting a very low albumin concentration in the glomerular ultrafiltrate. Conclusions. We report here the efficient genetic ablation of megalin, cubilin or both, using a Cre transgene driven by the Wnt4 promoter. The viable megalin/cubilin double-deficient mice now allow for detailed large-scale group analysis, and we anticipate that the mice will be of great value as an animal model for proximal tubulopathies with disrupted endocytosis.