Primary cilia regulate the osmotic stress response of renal epithelial cells through TRPM3

• Published in: American journal of physiology. Renal physiology Vol. 312; no. 4; p. F791
• Main Authors: Siroky, Brian J, Kleene, Nancy K, Kleene, Steven J, Varnell, Jr, Charles D, Comer, Raven G, Liu, Jialiu, Lu, Lu, Pachciarz, Nolan W, Bissler, John J, Dixon, Bradley P
• Format: Journal Article
• Language: English
• Published: United States 01-04-2017
• Subjects: Animals; Cell Line; Cilia - metabolism; CRISPR-Cas Systems; Epithelial Cells - drug effects; Epithelial Cells - metabolism; GABA Plasma Membrane Transport Proteins - genetics; GABA Plasma Membrane Transport Proteins - metabolism; Gene Editing; Hydroxyprostaglandin Dehydrogenases - genetics; Hydroxyprostaglandin Dehydrogenases - metabolism; Kidney Tubules, Collecting - drug effects; Kidney Tubules, Collecting - metabolism; Mice; Mice, Inbred C57BL; Mice, Transgenic; Osmoregulation - drug effects; Osmotic Pressure - drug effects; Saline Solution, Hypertonic - pharmacology; Signal Transduction; Transfection; TRPM Cation Channels - genetics; TRPM Cation Channels - metabolism; TRPV Cation Channels - genetics; TRPV Cation Channels - metabolism; osmoregulation; primary cilium; TRPV4; TRPM3
• ISSN: 1522-1466
• DOI: 10.1152/ajprenal.00465.2015

Primary cilia sense environmental conditions, including osmolality, but whether cilia participate in the osmotic response in renal epithelial cells is not known. The transient receptor potential (TRP) channels TRPV4 and TRPM3 are osmoresponsive. TRPV4 localizes to cilia in certain cell types, while renal subcellular localization of TRPM3 is not known. We hypothesized that primary cilia are required for maximal activation of the osmotic response of renal epithelial cells and that ciliary TRPM3 and TRPV4 mediate that response. Ciliated [murine epithelial cells from the renal inner medullary collecting duct (mIMCD-3) and 176-5] and nonciliated (176-5Δ) renal cells expressed
and
Ciliary expression of TRPM3 was observed in mIMCD-3 and 176-5 cells and in wild-type mouse kidney tissue. TRPV4 was identified in cilia and apical membrane of mIMCD-3 cells by electrophysiology and in the cell body by immunofluorescence. Hyperosmolal stress at 500 mOsm/kg (via NaCl addition) induced the osmotic response genes betaine/GABA transporter (
) and aldose reductase (
) in all ciliated cell lines. This induction was attenuated in nonciliated cells. A TRPV4 agonist abrogated
and
induction in ciliated and nonciliated cells. A TRPM3 agonist attenuated
and
induction in ciliated cells only. TRPM3 knockout attenuated
induction. Viability under osmotic stress was greater in ciliated than nonciliated cells.
induction was also less in nonciliated than ciliated cells when mannitol was used to induce hyperosmolal stress. These findings suggest that primary cilia are required for the maximal osmotic response in renal epithelial cells and that TRPM3 is involved in this mechanism. TRPV4 appears to modulate the osmotic response independent of cilia.