title: Exocytosis-Mediated Urinary Full-Length Megalin Excretion Is Linked With the Pathogenesis of Diabetic Nephropathy.
abstract: Efficient biomarkers for diabetic nephropathy (DN) have not been established. Using ELISA, we found previously that urinary levels of full-length megalin (C-megalin), a multiligand endocytic receptor in proximal tubules, was positively correlated with DN progression in patients with type 2 diabetes mellitus (T2DM). Here, we found that urinary extracellular vesicle (UEV) excretion and C-megalin content in UEVs or in their exosomal fraction increased along with the progression of the albuminuric stages in patients with T2DM. Cultured immortalized rat proximal tubule cells (IRPTCs) treated with fatty acid-free BSA or advanced glycation end product-modified BSA (AGE-BSA), endocytic ligands of megalin, increased EV excretion, and their C-megalin content. C-megalin excretion from IRPTCs via extracellular vesicles was significantly blocked by an exosome-specific inhibitor, GW4869, indicating that this excretion is mainly exocytosis-mediated. AGE-BSA treatment of IRPTCs caused apparent lysosomal dysfunction, which stimulated multivesicular body formation, resulting in increased exosomal C-megalin excretion. In a high-fat diet-induced, megalin-mediated kidney injury model in mice, urinary C-megalin excretion also increased via UEVs. Collectively, exocytosis-mediated urinary C-megalin excretion is associated with the development and progression of DN in patients with T2DM, particularly due to megalin-mediated lysosomal dysfunction in proximal tubules, and hence it could be a candidate biomarker linked with DN pathogenesis.
authors.affiliation: Division of Clinical Nephrology and Rheumatology, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata, Niigata, Japan.|Department of Applied Molecular Medicine, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata, Niigata, Japan.
authors.forename: Shankhajit
authors.initials: S
authors.lastname: De
authors.affiliation: Department of Applied Molecular Medicine, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata, Niigata, Japan.
authors.forename: Shoji
authors.initials: S
authors.lastname: Kuwahara
authors.affiliation: Department of Clinical Nutrition Science, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata, Niigata, Japan.
authors.forename: Michihiro
authors.initials: M
authors.lastname: Hosojima
authors.affiliation: Division of Clinical Nephrology and Rheumatology, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata, Niigata, Japan.
authors.forename: Tomomi
authors.initials: T
authors.lastname: Ishikawa
authors.affiliation: Division of Clinical Nephrology and Rheumatology, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata, Niigata, Japan.
authors.forename: Ryohei
authors.initials: R
authors.lastname: Kaseda
authors.affiliation: Division of Clinical Nephrology and Rheumatology, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata, Niigata, Japan.|Department of Applied Molecular Medicine, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata, Niigata, Japan.
authors.forename: Piyali
authors.initials: P
authors.lastname: Sarkar
authors.affiliation: Division of Molecular and Cellular Medicine, National Cancer Center Research Institute, Chuo-ku, Tokyo, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Yoshioka
authors.affiliation: Department of Clinical Nutrition Science, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata, Niigata, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Kabasawa
authors.affiliation: Division of Clinical Nephrology and Rheumatology, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata, Niigata, Japan.
authors.forename: Tomomichi
authors.initials: T
authors.lastname: Iida
authors.affiliation: Division of Clinical Nephrology and Rheumatology, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata, Niigata, Japan.
authors.forename: Sawako
authors.initials: S
authors.lastname: Goto
authors.affiliation: Division of Clinical Nephrology and Rheumatology, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata, Niigata, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Toba
authors.affiliation: Division of Clinical Nephrology and Rheumatology, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata, Niigata, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Higuchi
authors.affiliation: Health Administration Center, Niigata University, Nishi-ku, Niigata, Niigata, Japan.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Suzuki
authors.affiliation: Department of Pediatrics, Yoshida Hospital, Tsubame, Niigata, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Hara
authors.affiliation: Diagnostics Research Department, Life Innovation Research Institute, DENKA Innovation Center, Denka Co., Ltd., Machida, Tokyo, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kurosawa
authors.affiliation: Division of Clinical Nephrology and Rheumatology, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata, Niigata, Japan.
authors.forename: Ichiei
authors.initials: I
authors.lastname: Narita
authors.affiliation: Diagnostics Research Department, Life Innovation Research Institute, DENKA Innovation Center, Denka Co., Ltd., Machida, Tokyo, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Hirayama
authors.affiliation: Division of Molecular and Cellular Medicine, National Cancer Center Research Institute, Chuo-ku, Tokyo, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Ochiya
authors.affiliation: Department of Applied Molecular Medicine, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata, Niigata, Japan akisaito@med.niigata-u.ac.jp.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Saito
mesh_terms: D058186:Acute Kidney Injury / Q000378:metabolism; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000378:metabolism* / Q000652:urine; D003928:Diabetic Nephropathies / Q000209:etiology / Q000378:metabolism* / Q000652:urine; D059305:Diet, High-Fat; D005089:Exocytosis; D000067128:Extracellular Vesicles / Q000378:metabolism* / Q000648:ultrastructure; D005260:Female; D017127:Glycation End Products, Advanced / Q000494:pharmacology; D006801:Humans; D015151:Immunoblotting; D007687:Kidney Tubules, Proximal / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D026561:Low Density Lipoprotein Receptor-Related Protein-2 / Q000378:metabolism*; D008297:Male; D051379:Mice; D035683:MicroRNAs; D046529:Microscopy, Electron, Transmission; D016253:Microscopy, Immunoelectron; D008875:Middle Aged; D012333:RNA, Messenger; D051381:Rats; D012710:Serum Albumin, Bovine / Q000494:pharmacology
chemical_list: D017127:Glycation End Products, Advanced; D026561:Low Density Lipoprotein Receptor-Related Protein-2; D035683:MicroRNAs; D012333:RNA, Messenger; C081628:advanced glycation end products-bovine serum albumin; D012710:Serum Albumin, Bovine