Exosomal GAPDH from Proximal Tubule Cells Regulate ENaC Activity.
Exosomes are nanometer-scale, cell-derived vesicles that contain various molecules including nucleic acids, proteins, and lipids. These vesicles can release their cargo into adjacent or distant cells and mediate intercellular communication and cellular function. Here we examined the regulation of epithelial sodium channels in mpkCCD cells and distal tubule Xenopus 2F3 cells by exosomes isolated from proximal tubule LLC-PK1 cells. Cultured mpkCCD cells were stained with CTX coupled to a green fluorophore in order to label the cell membranes and freshly isolated exosomes from LLC-PK1 cells were labeled with the red lipophilic dye PKH26 in order to visualize uptake of exosomes into the cells. Single-channel patch clamp recordings showed the open probability of ENaC in Xenopus 2F3 cells and in freshly isolated split-open tubules decreased in response to exogenous application of exosomes derived from LLC-PK1 proximal tubule cells. Active GAPDH was identified within exosomes derived from proximal tubule LLC-PK1 cells. The effect on ENaC activity in Xenopus 2F3 cells was blunted after application of exosomes transfected with the GAPDH inhibitor heptelidic acid. Also, we show GAPDH and ENaC subunits associate in mpkCCD cells. These studies examine a potential role for exosomes in the regulation of ENaC activity and examine a possible mechanism for communication from proximal tubule cells to distal tubule and collecting duct cells.
Department of Radiation Oncology, Emory University School of Medicine, Atlanta, Georgia.
Kishore Kumar
KK
Jella
College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, Jiangsu Province, China.
Ling
L
Yu
Department of Physiology, Emory University School of Medicine, Atlanta, Georgia.
Qiang
Q
Yue
Department of Physiology, Emory University School of Medicine, Atlanta, Georgia.
Daniel
D
Friedman
Department of Physiology, Emory University School of Medicine, Atlanta, Georgia.
Billie J
BJ
Duke
Department of Physiology and Functional Genomics and Department of Medicine Division of Nephrology, Hypertension, and Renal Transplantation, University of Florida College of Medicine, Gainesville, Florida, United States of America.
Abdel A
AA
Alli
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D053503:Epithelial Sodium Channels / Q000737:chemistry / Q000378:metabolism*; D055354:Exosomes / Q000378:metabolism*; D005260:Female; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000378:metabolism*; D007687:Kidney Tubules, Proximal / Q000166:cytology*; D008297:Male; D051379:Mice; D021381:Protein Transport
D053503:Epithelial Sodium Channels; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases