title: Angiotensin II induces membrane trafficking of natively expressed transient receptor potential vanilloid type 4 channels in hypothalamic 4B cells.
abstract: Transient receptor potential vanilloid family type 4 (TRPV4) channels are expressed in central neuroendocrine neurons and have been shown to be polymodal in other systems. We previously reported that in the rodent, a model of dilutional hyponatremia associated with hepatic cirrhosis, TRPV4 expression is increased in lipid rafts from the hypothalamus and that this effect may be angiotensin dependent. In this study, we utilized the immortalized neuroendocrine rat hypothalamic 4B cell line to more directly test the effects of angiotensin II (ANG II) on TRPV4 expression and function. Our results demonstrate the expression of corticotropin-releasing factor (CRF) transcripts, for sex-determining region Y (SRY) (male genotype), arginine vasopressin (AVP), TRPV4, and ANG II type 1a and 1b receptor in 4B cells. After a 1-h incubation in ANG II (100 nM), 4B cells showed increased TRPV4 abundance in the plasma membrane fraction, and this effect was prevented by the ANG II type 1 receptor antagonist losartan (1 μM) and by a Src kinase inhibitor PP2 (10 μM). Ratiometric calcium imaging experiments demonstrated that ANG II incubation potentiated TRPV4 agonist (GSK 1016790A, 20 nM)-induced calcium influx (control 18.4 ± 2.8% n = 5 and ANG II 80.5 ± 2.4% n = 5). This ANG II-induced increase in calcium influx was also blocked by 1 μM losartan and 10 μM PP2 (losartan 26.4 ± 3.8% n = 5 and PP2 19.7 ± 3.9% n = 5). Our data suggests that ANG II can increase TRPV4 channel membrane expression in 4B cells through its action on AT1R involving a Src kinase pathway.
authors: Department of Integrative Physiology and Anatomy and Cardiovascular Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas;
authors: Ashwini
authors: A
authors: Saxena
authors: Department of Integrative Physiology and Anatomy and Cardiovascular Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas;
authors: Martha
authors: M
authors: Bachelor
authors: Department of Pharmacology and Neuroscience & North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas; and.
authors: Yong H
authors: YH
authors: Park
authors: Department of Pharmacology & Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, Texas.
authors: Flavia R
authors: FR
authors: Carreno
authors: Department of Integrative Physiology and Anatomy and Cardiovascular Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas;
authors: T Prashant
authors: TP
authors: Nedungadi
authors: Department of Integrative Physiology and Anatomy and Cardiovascular Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas; Tom.Cunningham@unthsc.edu.
authors: J Thomas
authors: JT
authors: Cunningham
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D002478:Cells, Cultured; D007031:Hypothalamus / Q000187:drug effects* / Q000378:metabolism* / Q000473:pathology; D007930:Leucine / Q000031:analogs & derivatives / Q000494:pharmacology; D021962:Membrane Microdomains / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D009025:Morpholines / Q000494:pharmacology; D021381:Protein Transport / Q000187:drug effects; D011758:Pyrroles / Q000494:pharmacology; D051381:Rats; D044140:Receptor, Angiotensin, Type 1 / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D013449:Sulfonamides / Q000494:pharmacology; D050916:TRPV Cation Channels / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: C573308:HC-067047; D009025:Morpholines; C530602:N-(1-((4-(2-(((2,4-dichlorophenyl)sulfonyl)amino)-3-hydroxypropanoyl)-1-piperazinyl)carbonyl)-3-methylbutyl)-1-benzothiophene-2-carboxamide; D011758:Pyrroles; D044140:Receptor, Angiotensin, Type 1; D013449:Sulfonamides; D050916:TRPV Cation Channels; C486577:Trpv4 protein, rat; D000804:Angiotensin II; D019061:src-Family Kinases; D007930:Leucine; D002118:Calcium
keywords: 4B; SRC kinase; SRY; TRPV4; angiotensin; hypothalamus