Modulating TRPV4 channels with paclitaxel and lithium.

Transient receptor potential V4 (TRPV4), a plasma membrane calcium channel, is implicated as a contributor to the initiation of chemotherapy-induced peripheral neuropathy (CIPN). Paclitaxel (PTX) is a commonly used anticancer drug that causes CIPN and lithium has been shown to prevent CIPN. However, the direct effect of PTX and lithium on TRPV4 is not clear. This study investigated these actions using biochemical, pharmacological, and electrophysiological approaches using a neuronal cell line (SH-SY5Y). The addition of pharmacologically appropriate levels of PTX increased the expression of TRPV4, TRPV4 currents, and TRPV4-dependent calcium fluxes. Prolonged exposure to PTX amplified the acute effects of TRPV4 expression, currents, and calcium fluxes. Pretreatment with lithium (1 mM) decreased TRPV4 currents and calcium fluxes in the absence and presence of PTX. These findings enhance our understanding of the properties and regulation of TRPV4, the cellular mechanisms of PTX-induced neuropathy, and the mechanism of lithium for prevention of CIPN.