title: Knockdown of ApoL1 in Zebrafish Larvae Affects the Glomerular Filtration Barrier and the Expression of Nephrin.
abstract: APOL1, a secreted high-density lipoprotein, is expressed in different human tissues. Genetic variants of APOL1 are described to be associated with the development of end stage renal diseases in African Americans. In human kidney, APOL1 is mainly expressed in podocytes that are responsible for proper blood filtration. Since mice do not express ApoL1, the zebrafish is an ideal model to study the role of ApoL1. Injection of morpholinos against zApoL1 into zebrafish eggs and larvae, respectively, induces severe edema indicating a leakage of the filtration barrier. This was demonstrated in zApoL1 knockdown larvae by intravascular injection of fluorescently-labeled 10- and 500-kDa dextrans and by clearance of the vitamin D-binding protein from the circulation. Immunohistochemistry and RT-PCR revealed the reduction of nephrin, a podocyte-specific protein essential for blood filtration. Coinjection of human nephrin mRNA rescued the zApoL1 knockdown induced phenotype. Reduced APOL1 and nephrin levels were also found in biopsies of patients suffering from end stage renal diseases. Our results demonstrate that zApoL1 is essential for proper blood filtration in the zebrafish glomerulus and that zApoL1 affects the expression of nephrin.
authors.affiliation: Institute of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany.|Department of Anatomy and Histology, Faculty of Veterinary Medicine, Assiut University, Assiut, Egypt.
authors.forename: Ahmed M
authors.initials: AM
authors.lastname: Kotb
authors.affiliation: Institute of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany.
authors.forename: Ole
authors.initials: O
authors.lastname: Simon
authors.affiliation: Institute of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany.
authors.forename: Antje
authors.initials: A
authors.lastname: Blumenthal
authors.affiliation: Institute of Pathology, University Medicine Greifswald, Greifswald, Germany.
authors.forename: Silke
authors.initials: S
authors.lastname: Vogelgesang
authors.affiliation: Institute of Pathology, University Medicine Greifswald, Greifswald, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Dombrowski
authors.affiliation: Department of Nephropathology, Institute of Pathology, University Hospital Erlangen, Erlangen, Germany.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Amann
authors.affiliation: Department of Urology, University Medicine Greifswald, Greifswald, Germany.
authors.forename: Uwe
authors.initials: U
authors.lastname: Zimmermann
authors.affiliation: Institute of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany.
authors.forename: Karlhans
authors.initials: K
authors.lastname: Endlich
authors.affiliation: Institute of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany.
authors.forename: Nicole
authors.initials: N
authors.lastname: Endlich
mesh_terms: D000818:Animals; D001053:Apolipoproteins / Q000172:deficiency* / Q000235:genetics*; D004487:Edema / Q000378:metabolism; D004727:Endothelium / Q000378:metabolism; D005786:Gene Expression Regulation / Q000235:genetics*; D060730:Glomerular Filtration Barrier / Q000378:metabolism*; D007814:Larva / Q000235:genetics* / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics*; D009928:Organ Specificity; D010496:Pericardium / Q000378:metabolism; D050199:Podocytes / Q000378:metabolism; D015027:Zebrafish / Q000235:genetics* / Q000378:metabolism; D029961:Zebrafish Proteins / Q000172:deficiency* / Q000235:genetics*
chemical_list: C000621446:ApoL1 protein, zebrafish; D001053:Apolipoproteins; D008565:Membrane Proteins; D029961:Zebrafish Proteins; C113267:nephrin