Dataset Information

Distance constraints on activation of TRPV4 channels by AKAP150-bound PKCα in arterial myocytes.

ABSTRACT: TRPV4 (transient receptor potential vanilloid 4) channels are Ca²⁺-permeable channels that play a key role in regulating vascular tone. In arterial myocytes, opening of TRPV4 channels creates local increases in Ca²⁺ influx, detectable optically as "TRPV4 sparklets." TRPV4 sparklet activity can be enhanced by the action of the vasoconstrictor angiotensin II (AngII). This modulation depends on the activation of subcellular signaling domains that comprise protein kinase C α (PKCα) bound to the anchoring protein AKAP150. Here, we used super-resolution nanoscopy, patch-clamp electrophysiology, Ca²⁺ imaging, and mathematical modeling approaches to test the hypothesis that AKAP150-dependent modulation of TRPV4 channels is critically dependent on the distance between these two proteins in the sarcolemma of arterial myocytes. Our data show that the distance between AKAP150 and TRPV4 channel clusters varies with sex and arterial bed. Consistent with our hypothesis, we further find that basal and AngII-induced TRPV4 channel activity decays exponentially as the distance between TRPV4 and AKAP150 increases. Our data suggest a maximum radius of action of ∼200 nm for local modulation of TRPV4 channels by AKAP150-associated PKCα.

SUBMITTER: Tajada S

PROVIDER: S-EPMC5460949 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature

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Distance constraints on activation of TRPV4 channels by AKAP150-bound PKCα in arterial myocytes.

Tajada Sendoa S Moreno Claudia M CM O'Dwyer Samantha S Woods Sean S Sato Daisuke D Navedo Manuel F MF Santana L Fernando LF

The Journal of general physiology 20170515 6

TRPV4 (transient receptor potential vanilloid 4) channels are Ca<sup>2+</sup>-permeable channels that play a key role in regulating vascular tone. In arterial myocytes, opening of TRPV4 channels creates local increases in Ca<sup>2+</sup> influx, detectable optically as "TRPV4 sparklets." TRPV4 sparklet activity can be enhanced by the action of the vasoconstrictor angiotensin II (AngII). This modulation depends on the activation of subcellular signaling domains that comprise protein kinase C α (P ...[more]

PMID: 28507079

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Project description:Background: Dysregulation of TRPV4-mediated signaling has been associated with inflammation and tissue fibrosis, both of which are key features in the pathophysiology of lymphatic system diseases; however, the expression and functional roles of lymphatic TRPV4 channels remain largely unexplored. Methods: We generated a single-cell RNA sequencing dataset from microdissected mouse collecting lymphatic vessels to characterize the expression of Trpv4. Using a novel Trpv4fx/fx mouse strain and the Cre-lines Prox1-CreERT2 and LysM-Cre we assessed the role of TRPV4 channels in lymphatic endothelial cells (LECs) and peri-lymphatic myeloid cells, respectively. Confocal microscopy and extensive functional experimentation on isolated and pressurized lymphatics, including measurements of intracellular calcium activity, were employed to validate our scRNAseq findings and to elucidate the underlying mechanisms. Clinical significance was assessed using biopsies from breast cancer-related lymphedema (BCRL) patients. Results: We characterized the single-cell transcriptome of collecting lymphatic vessels and surrounding tissues. Trpv4 was highly enriched in LECs and in a subset of Lyve1+ macrophages displaying a tissue-resident profile. In clinical samples, BCRL was associated with increased infiltration of macrophages co-expressing LYVE1 and TRPV4. Pharmacological activation of TRPV4 channels led to contractile dysregulation in isolated collecting lymphatics. The response was multi-phasic, including initial vasospasm and subsequent vasodilation and inhibition of contractions, which was associated with the activation of thromboxane A2 receptors (TXA2Rs) in lymphatic muscle cells (LMCs) by secreted prostanoids from TRPV4+ myeloid cells, and increased nitric oxide (and perhaps other vasodilatory prostanoids) from LECs. The TXA2R-mediated vasospasm resulted from increased mobilization of calcium from intracellular stores through IP3 receptors and store-operated calcium entry. Conclusions: Our results uncovered a novel mechanism of lymphatic contractile dysregulation mediated by the crosstalk between TRPV4-expressing myeloid cells, including LYVE1+ macrophages, and LMCs or LECs. These findings highlight potentially important roles of TRPV4 channels in lymphatic dysfunction associated with inflammation, including secondary lymphedema.

Dataset Information

Distance constraints on activation of TRPV4 channels by AKAP150-bound PKCα in arterial myocytes.

Publications

Distance constraints on activation of TRPV4 channels by AKAP150-bound PKCα in arterial myocytes.

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