Small molecule dual-inhibitors of TRPV4 and TRPA1 for attenuation of inflammation and pain

Abstract

TRPV4 ion channels represent osmo-mechano-TRP channels with pleiotropic function and wide-spread expression. One of the critical functions of TRPV4 in this spectrum is its involvement in pain and inflammation. However, few small-molecule inhibitors of TRPV4 are available. Here we developed TRPV4-inhibitory molecules based on modifications of a known TRPV4-selective tool-compound, GSK205. We not only increased TRPV4-inhibitory potency, but surprisingly also generated two compounds that potently co-inhibit TRPA1, known to function as chemical sensor of noxious and irritant signaling. We demonstrate TRPV4 inhibition by these compounds in primary cells with known TRPV4 expression - articular chondrocytes and astrocytes. Importantly, our novel compounds attenuate pain behavior in a trigeminal irritant pain model that is known to rely on TRPV4 and TRPA1. Furthermore, our novel dual-channel blocker inhibited inflammation and pain-associated behavior in a model of acute pancreatitis – known to also rely on TRPV4 and TRPA1. Our results illustrate proof of a novel concept inherent in our prototype compounds of a drug that targets two functionally-related TRP channels, and thus can be used to combat isoforms of pain and inflammation in-vivo that involve more than one TRP channel. This approach could provide a novel paradigm for treating other relevant health conditions.

Calcium signaling of in situ chondrocytes in articular cartilage under compressive loading: Roles of calcium sources and cell membrane ion channels

“…TRPV4 ion channel can be activated by various stimuli, including osmotic stress, mechanical loading, and heat. TRPV4 plays a key role in regulating calcium homeostasis and matrix metabolism in cartilage, while TRPV4‐dysfunction is associated with the development of osteoarthritis . In the compressed cartilage, both mechanical loading and osmotic stress can activate the TRPV4 channel and initiate the [Ca 2+ ] i transients.…”

“…TRPV4 plays a key role in regulating calcium homeostasis and matrix metabolism in cartilage, 10,41 while TRPV4-dysfunction is associated with the development of osteoarthritis. [42][43][44] In the compressed cartilage, both mechanical loading and osmotic stress can activate the TRPV4 channel and initiate the [Ca 2þ ] i transients. In this study, inhibition of TRPV4 significantly reduced the [Ca 2þ ] i responses in loaded cartilage.…”

Pleiotropic function of TRPV4 ion channels in the central nervous system

“…Neuronal TRPV4 channels may therefore be an important therapeutic target for cognitive, motor and ageing-related disorders. TRPV4 inhibitors have been described and were recently described as orally available compounds (Jia et al 2004;Krause et al 2005;Phan et al 2009;Vincent et al 2009;Morty & Kuebler, 2014;Feetham et al 2015;Qi et al 2015) and also as 'dual inhibitors' of TRPV4 and TRPA1 (Kanju et al 2016), which might be an attractive possibility given the postulated function of astrocytic TRPA1 (Lee et al 2012;Shigetomi et al 2012Shigetomi et al , 2013Wei et al 2016). Such inhibitors, if they are intended for oral use, will have to pass through the blood-brain barrier (although, for example, the blood-brain barrier is more penetrable in certain CNS disorders, such as multiple sclerosis).…”

“…) and also as ‘dual inhibitors’ of TRPV4 and TRPA1 (Kanju et al . ), which might be an attractive possibility given the postulated function of astrocytic TRPA1 (Lee et al . ; Shigetomi et al .…”

Systems approaches in osteoarthritis: Identifying routes to novel diagnostic and therapeutic strategies

“…Defining differential mechanotransduction pathways for age‐ and trauma‐associated OA could establish therapeutic targets. Modifications to a known small molecule TRPV4‐antagonist has shown analgesic and anti‐inflammatory properties that could have potential in a number of conditions including osteoarthritis 78. This case‐study demonstrates that a systems orientated approach (running in this case from ‘top down’) can reveal regulatory targets by modelling the integration of mechanical signals to establishing common mechanotransduction mechanisms and unravelling age‐associated contribution to biomechanical failures.…”