Salicylate restores transport function and anion exchanger activity of missense pendrin mutations.
The SLC26A4 gene encodes the transmembrane protein pendrin, which is involved in the homeostasis of the ion concentration of the endolymph of the inner ear, most likely by acting as a chloride/bicarbonate transporter. Mutations in the SLC26A4 gene cause sensorineuronal hearing loss. However, the mechanisms responsible for such loss have remained unknown. Therefore, in this study, we focused on the function of ten missense pendrin mutations (p.P123S (Pendred syndrome), p.M147V (NSEVA), p.K369E (NSEVA), p.A372V (Pendred syndrome/NSEVA), p.N392Y (Pendred syndrome), p.C565Y (NSEVA), p.S657N (NSEVA), p.S666F (NSEVA), p.T721M (NSEVA) and p.H723R (Pendred syndrome/NSEVA)) reported in Japanese patients, and analyzed their cellular localization and anion exchanger activity using HEK293 cells transfected with each mutant gene. Immunofluorescent staining of the cellular localization of the pendrin mutants revealed that p.K369E and p.C565Y, as well as wild-type pendrin, were transported to the plasma membrane, while 8 other mutants were retained in the cytoplasm. Furthermore, we analyzed whether salicylate, as a pharmacological chaperone, restores normal plasma membrane localization of 8 pendrin mutants retained in the cytoplasm to the plasma membrane. Incubation with 10 mM of salicylate of the cells transfected with the mutants induced the transport of 4 pendrin mutants (p.P123S, p.M147V, p.S657Y and p.H723R) from the cytoplasm to the plasma membrane and restored the anion exchanger activity. These findings suggest that salicylate might contribute to development of a new method of medical treatment for sensorineuronal hearing loss caused by the mutation of the deafness-related proteins, including pendrin.
Ishihara
Kenji
K
Department of Bioengineering and Robotics, Graduate School of Engineering, Tohoku University, Sendai, Miyagi, Japan.
Okuyama
Shuhei
S
Kumano
Shun
S
Iida
Koji
K
Hamana
Hiroshi
H
Murakoshi
Michio
M
Kobayashi
Toshimitsu
T
Usami
Shinichi
S
Ikeda
Katsuhisa
K
Haga
Yoichi
Y
Tsumoto
Kohei
K
Nakamura
Hiroyuki
H
Hirasawa
Noriyasu
N
Wada
Hiroshi
H
D044466:Asian People / Q000235:genetics; D001692:Biological Transport; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002470:Cell Survival; D003593:Cytoplasm / Q000378:metabolism; D006319:Hearing Loss, Sensorineural / Q000188:drug therapy* / Q000208:ethnology / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007564:Japan; D026901:Membrane Transport Proteins / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D008856:Microscopy, Fluorescence; D020125:Mutation, Missense; D021381:Protein Transport; D012459:Salicylates / Q000494:pharmacology*; D000076988:Sulfate Transporters; D014162:Transfection
D026901:Membrane Transport Proteins; C085609:SLC26A4 protein, human; D012459:Salicylates; D000076988:Sulfate Transporters