Inhibition of gastric H+,K+-ATPase by new dihydropyrazole derivative KYY-008

Parkinson's disease-associated ATP13A2/PARK9 functions as a lysosomal H+,K+-ATPase

Mutations in the human ATP13A2 (PARK9), a lysosomal ATPase, cause Kufor-Rakeb Syndrome, an early-onset form of Parkinson's disease (PD). Here, we demonstrate that ATP13A2 functions as a lysosomal H⁺,K⁺-ATPase. The K⁺-dependent ATPase activity and the lysosomal K⁺-transport activity of ATP13A2 are inhibited by an inhibitor of sarco/endoplasmic reticulum Ca²⁺-ATPase, thapsigargin, and K⁺-competitive inhibitors of gastric H⁺,K⁺-ATPase, such as vonoprazan and SCH28080. Interestingly, these H⁺,K⁺-ATPase inhibitors cause lysosomal alkalinization and α-synuclein accumulation, which are pathological hallmarks of PD. Furthermore, PD-associated mutants of ATP13A2 show abnormal expression and function. Our results suggest that the H⁺/K⁺-transporting function of ATP13A2 contributes to acidification and α-synuclein degradation in lysosomes.

Nine geranylgeranylated derivatives isolated from the roots of Rhus chinensis Mill

Nine undescribed geranylgeranylated derivatives (chinensens A-G), including malic acid derivative (A) and phenolic derivatives (B-E), as well as two pairs of enantiomers, [(R), (S)]-chinensens F and [(R), (S)]-chinensens G, were isolated from the roots of Rhus chinensis Mill. Their structures were elucidated by UV, IR, HRESIMS, 1D and 2D NMR spectra, as well as optical rotations. The 95% EtOH extract (95% EXT, 500 mg/kg, p. o.) of the roots of Rhus chinensis and the 95% EtOH fraction (95% FRA, 500 mg/kg, p. o.) from the microporous resin column significantly alleviated indomethacin-induced or water immersion-restraint stress-induced damage in rat gastric mucosa with inhibitory rates from 53% to 89%. The racemic mixture (chinensen G) and its enantiomers [(R), (S)]-chinensens G showed weak activities against H⁺,K⁺-ATPase (20%-24%) at a concentration of 0.1 mM, respectively.