Activation of transient receptor potential vanilloid 1 by lipoxygenase metabolites depends on PKC phosphorylation

Abstract

Peripheral neuronal activation by inflammatory mediators is a multifaceted physiological response that involves a multitude of regulated cellular functions. One key pathway that has been shown to be involved in inflammatory pain is Gq/GPCR, whose activation by inflammatory mediators is followed by the regulated response of the cation channel transient receptor potential vanilloid 1 (TRPV1). However, the mechanism that underlies TRPV1 activation downstream of the Gq/GPCR pathway has yet to be fully defined. In this study, we employ pharmacological and molecular biology tools to dissect this activation mechanism perforated-patch recordings and calcium imaging of both neurons and a heterologous system. We showed that TRPV1 activity downstream of Gq/GPCR activation only produced a subdued current, which was noticeably different from the robust current that is typical of TRPV1 activation by exogenous stimuli. Moreover, we specifically demonstrated that 2 pathways downstream of Gq/GPCR signaling, namely endovanilloid production by lipoxygenases and channel phosphorylation by PKC, converge on TRPV1 to evoke a tightly regulated response. Of importance, we show that only when both pathways are acting on TRPV1 is the inflammatory-mediated response achieved. We propose that the requirement of multiple signaling events allows subdued TRPV1 activation to evoke regulated neuronal response during inflammation.-Kumar R., Hazan, A., Geron, M., Steinberg, R., Livni, L., Matzner, H., Priel, A. Activation of transient receptor potential vanilloid 1 by lipoxygenase metabolites depends on PKC phosphorylation.

GTL-1, a Calcium Activated TRPM Channel, Enhances Nociception

“…Voltage-clamp recordings from transfected HEK293T cell were carried out as previously described (Kumar et al, 2017;Geron et al, 2018). Briefly, membrane currents were recorded under the voltage-clamp using an Axopatch 200B patch-clamp amplifier (Molecular Devices, Sunnyvale, CA, USA).…”

“…The inside-out configuration was performed as previously described (Kumar et al, 2017). Briefly, both the pipette solution and intracellular solutions constituted (mM): 150 NaCl, 2.8 KCl, 2 CaCl 2 , and 10 HEPES, adjusted to pH 7.4 with NaOH.…”

“…The perforated-patch configuration was carried out as previously described (Priel and Silberberg, 2004;Kumar et al, 2017). Briefly, the pipette solution constituted (mM): 75 K 2 SO 4 , 55 KCl, 5 MgSO 4 , 10 HEPES, adjusted to pH 7.2 with KOH.…”

Topically injected adrenocorticotropic hormone induces mechanical hypersensitivity on a full‐thickness cutaneous wound model in rats

“…Accordingly, this leads to our second hypothesis that the antagonists for the four ion channels cancel ACTH‐induced mechanical hypersensitivity. It is well known that TRPV1 and TRPA1 are activated by PKC‐ and/or PKA‐induced phosphorylation . Additionally, ACTH‐binding MC2R activates PKC and PKA .…”

Na+/Ca2+ exchanger 1 is a key mechanosensitive molecule of the esophageal myenteric neurons

“…[20][21][22] Neuronal [Ca 2+ ] cyt homeostasis is precisely controlled by multiple cellular mechanisms, including extracellular Ca 2+ entry through the plasma membrane. 23,24 Different Ca 2+ entry pathways, such as voltage-gated Ca 2+ channels (VGCC), 25,26 receptor-operated Ca 2+ channels (ROC) 27,28 and store-operated Ca 2+ channels (SOC) 29,30 have been identified in various types of neurons, including enteric neurons. Ca 2+ -permeable channels activated by mechanical stretch, so-called stretch-activated cation channels (SAC), have also been found in the enteric neurons.…”