title: Exosomal transfer from human renal proximal tubule cells to distal tubule and collecting duct cells.
abstract: OBJECTIVE
  Exosomes are 50-90nm extracellular membrane particles that may mediate trans-cellular communication between cells and tissues. We have reported that human urinary exosomes contain miRNA that are biomarkers for salt sensitivity and inverse salt sensitivity of blood pressure. This study examines exosomal transfer between cultured human renal proximal tubule cells (RPTCs) and from RPTCs to human distal tubule and collecting duct cells.
  
  
  METHODS
  For RPTC-to-RPTC exosomal transfer, we utilized 5 RPTC lines producing exosomes that were fluorescently labeled with exosomal-specific markers CD63-EGFP or CD9-RFP. Transfer between RPTCs was demonstrated by co-culturing CD63-EGFP and CD9-RFP stable clones and performing live confocal microscopy. For RPTC-to-distal segment exosomal transfer, we utilized 5 distal tubule and 3 collecting duct immortalized cell lines.
  
  
  RESULTS
  Time-lapse videos revealed unique proximal tubule cellular uptake patterns for exosomes and eventual accumulation into the multivesicular body. Using culture supernatant containing exosomes from 3 CD9-RFP and 2 CD63-EGFP RPTC cell lines, all 5 distal tubule cell lines and all 3 collecting duct cell lines showed exosomal uptake as measured by microplate fluorometry. Furthermore, we found that RPTCs stimulated with fenoldopam (dopamine receptor agonist) had increased production of exosomes, which upon transfer to distal tubule and collecting duct cells, reduced the basal reactive oxygen species (ROS) production rates in those recipient cells.
  
  
  CONCLUSIONS
  Due to the complex diversity of exosomal contents, this proximal-to-distal vesicular inter-nephron transfer may represent a previously unrecognized trans-renal communication system.
authors: The University of Virginia Health System, Department of Pathology, Charlottesville, VA, USA. Electronic address: jjg5b@virginia.edu.
authors: John J
authors: JJ
authors: Gildea
authors: The University of Virginia Health System, Department of Pathology, Charlottesville, VA, USA.
authors: Joscelyn E
authors: JE
authors: Seaton
authors: The University of Virginia Health System, Department of Pathology, Charlottesville, VA, USA.
authors: Ken G
authors: KG
authors: Victor
authors: The University of Virginia Health System, Department of Pathology, Charlottesville, VA, USA.
authors: Camellia M
authors: CM
authors: Reyes
authors: The University of Virginia Health System, Department of Pathology, Charlottesville, VA, USA.
authors: Dora
authors: D
authors: Bigler Wang
authors: The University of Virginia Health System, Department of Pathology, Charlottesville, VA, USA.
authors: Abigail C
authors: AC
authors: Pettigrew
authors: The University of Virginia Health System, Department of Pathology, Charlottesville, VA, USA.
authors: Crystal E
authors: CE
authors: Courtner
authors: The University of Virginia Health System, Department of Pathology, Charlottesville, VA, USA.
authors: Neema
authors: N
authors: Shah
authors: The University of Virginia Health System, Department of Pathology, Charlottesville, VA, USA.
authors: Hanh T
authors: HT
authors: Tran
authors: The University of Virginia Health System, Department of Pathology, Charlottesville, VA, USA.
authors: Robert E
authors: RE
authors: Van Sciver
authors: The University of Virginia Health System, Department of Pathology, Charlottesville, VA, USA.
authors: Julia M
authors: JM
authors: Carlson
authors: The University of Virginia Health System, Department of Pathology, Charlottesville, VA, USA.
authors: Robin A
authors: RA
authors: Felder
mesh_terms: D002450:Cell Communication; D002460:Cell Line; D055354:Exosomes / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007668:Kidney / Q000166:cytology / Q000378:metabolism; D007685:Kidney Tubules, Collecting / Q000166:cytology / Q000378:metabolism*; D007686:Kidney Tubules, Distal / Q000166:cytology / Q000378:metabolism*; D007687:Kidney Tubules, Proximal / Q000166:cytology / Q000378:metabolism*; D035683:MicroRNAs / Q000235:genetics; D009399:Nephrons / Q000378:metabolism; D060245:Tetraspanin 29 / Q000235:genetics; D060149:Tetraspanin 30 / Q000235:genetics
chemical_list: C554586:CD63 protein, human; C554869:CD9 protein, human; D035683:MicroRNAs; D060245:Tetraspanin 29; D060149:Tetraspanin 30
keywords: Collecting duct; Distal tubule; Dopamine; Exosomes; Proximal tubule; ROS