Chronic cough relief by allosteric modulation of P2X3 without taste disturbance.

P2X receptors are cation channels that sense extracellular ATP. Many therapeutic candidates targeting P2X receptors have begun clinical trials or acquired approval for the treatment of refractory chronic cough (RCC) and other disorders. However, the present negative allosteric modulation of P2X receptors is primarily limited to the central pocket or the site below the left flipper domain. Here, we uncover a mechanism of allosteric regulation of P2X3 in the inner pocket of the head domain (IP-HD), and show that the antitussive effects of quercetin and PSFL2915 (our nM-affinity P2X3 inhibitor optimized based on quercetin) on male mice and guinea pigs were achieved by preventing allosteric changes of IP-HD in P2X3. While being therapeutically comparable to the newly licensed P2X3 RCC drug gefapixant, quercetin and PSFL2915 do not have an adverse effect on taste as gefapixant does. Thus, allosteric modulation of P2X3 via IP-HD may be a druggable strategy to alleviate RCC.

Eriodictyol attenuates cisplatin-induced kidney injury by inhibiting oxidative stress and inflammation.

Eriodictyol, a flavonoid present in citrus fruits, has been reported to have antioxidant and anti-inflammatory effects. In this study, the protective effects of eriodictyol on cisplatin (CP)-induced kidney injury were detected. CP-induced kidney injury model was established by administration of CP (20mg/kg). The results showed that treatment of eriodictyol inhibited the production of blood urea nitrogen (BUN), creatinine, MDA, TBARS, reactive oxygen species (ROS), as well as the production of TNF-α, and IL-1ß in kidney tissues induced by CP. Eriodictyol also up-regulated the activities of SOD, CAT, and GSH-PX decreased by CP. Furthermore, eriodictyol was found to up-regulate the expression of Nrf2/HO-1 and inhibited CP-induced NF-κB activation in kidney tissues. In conclusion, eriodictyol protected against CP-induced kidney injury through activating Nrf2 and inhibiting NF-κB activation.